--- 1/draft-ietf-nfsv4-rfc3530bis-03.txt 2010-07-09 20:13:27.000000000 +0200 +++ 2/draft-ietf-nfsv4-rfc3530bis-04.txt 2010-07-09 20:13:29.000000000 +0200 @@ -1,31 +1,33 @@ NFSv4 T. Haynes -Internet-Draft Editor -Intended status: Standards Track March 05, 2010 -Expires: September 6, 2010 +Internet-Draft D. Noveck +Intended status: Standards Track Editors +Expires: January 8, 2011 July 07, 2010 NFS Version 4 Protocol - draft-ietf-nfsv4-rfc3530bis-03.txt + draft-ietf-nfsv4-rfc3530bis-04.txt Abstract The Network File System (NFS) version 4 is a distributed filesystem protocol which owes heritage to NFS protocol version 2, RFC 1094, and version 3, RFC 1813. Unlike earlier versions, the NFS version 4 protocol supports traditional file access while integrating support for file locking and the mount protocol. In addition, support for strong security (and its negotiation), compound operations, client caching, and internationalization have been added. Of course, attention has been applied to making NFS version 4 operate well in an - Internet environment. This document replaces RFC 3530 as the - definition of the NFS version 4 protocol. + Internet environment. + + This document, together with the companion XDR description document, + replaces RFC 3530 as the definition of the NFS version 4 protocol. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1]. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the @@ -40,21 +42,21 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - This Internet-Draft will expire on September 6, 2010. + This Internet-Draft will expire on January 8, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -71,263 +73,325 @@ modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents - 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 7 - 1.1. Changes since RFC 3530 . . . . . . . . . . . . . . . . . 7 - 1.2. Changes since RFC 3010 . . . . . . . . . . . . . . . . . 7 - 1.3. NFS Version 4 Goals . . . . . . . . . . . . . . . . . . 8 - 1.4. Inconsistencies of this Document with Section 18 . . . . 9 - 1.5. Overview of NFS version 4 Features . . . . . . . . . . . 9 - 1.5.1. RPC and Security . . . . . . . . . . . . . . . . . . 9 - 1.5.2. Procedure and Operation Structure . . . . . . . . . . 10 - 1.5.3. Filesystem Model . . . . . . . . . . . . . . . . . . 10 - 1.5.4. OPEN and CLOSE . . . . . . . . . . . . . . . . . . . 12 - 1.5.5. File locking . . . . . . . . . . . . . . . . . . . . 12 - 1.5.6. Client Caching and Delegation . . . . . . . . . . . . 13 - 1.6. General Definitions . . . . . . . . . . . . . . . . . . 13 - 2. Protocol Data Types . . . . . . . . . . . . . . . . . . . . . 15 - 2.1. Basic Data Types . . . . . . . . . . . . . . . . . . . . 15 - 2.2. Structured Data Types . . . . . . . . . . . . . . . . . 17 - 3. RPC and Security Flavor . . . . . . . . . . . . . . . . . . . 22 - 3.1. Ports and Transports . . . . . . . . . . . . . . . . . . 22 - 3.1.1. Client Retransmission Behavior . . . . . . . . . . . 23 - 3.2. Security Flavors . . . . . . . . . . . . . . . . . . . . 23 - 3.2.1. Security mechanisms for NFS version 4 . . . . . . . . 24 - 3.3. Security Negotiation . . . . . . . . . . . . . . . . . . 26 - 3.3.1. SECINFO . . . . . . . . . . . . . . . . . . . . . . . 26 - 3.3.2. Security Error . . . . . . . . . . . . . . . . . . . 27 - 3.3.3. Callback RPC Authentication . . . . . . . . . . . . . 27 - 4. Filehandles . . . . . . . . . . . . . . . . . . . . . . . . . 29 - 4.1. Obtaining the First Filehandle . . . . . . . . . . . . . 29 - 4.1.1. Root Filehandle . . . . . . . . . . . . . . . . . . . 29 - 4.1.2. Public Filehandle . . . . . . . . . . . . . . . . . . 30 - 4.2. Filehandle Types . . . . . . . . . . . . . . . . . . . . 30 - 4.2.1. General Properties of a Filehandle . . . . . . . . . 30 - 4.2.2. Persistent Filehandle . . . . . . . . . . . . . . . . 31 - 4.2.3. Volatile Filehandle . . . . . . . . . . . . . . . . . 31 - 4.2.4. One Method of Constructing a Volatile Filehandle . . 33 - 4.3. Client Recovery from Filehandle Expiration . . . . . . . 33 - 5. File Attributes . . . . . . . . . . . . . . . . . . . . . . . 34 - 5.1. Mandatory Attributes . . . . . . . . . . . . . . . . . . 35 - 5.2. Recommended Attributes . . . . . . . . . . . . . . . . . 35 - 5.3. Named Attributes . . . . . . . . . . . . . . . . . . . . 36 - 5.4. Classification of Attributes . . . . . . . . . . . . . . 36 - 5.5. Mandatory Attributes - Definitions . . . . . . . . . . . 37 - 5.6. Recommended Attributes - Definitions . . . . . . . . . . 39 - 5.7. Time Access . . . . . . . . . . . . . . . . . . . . . . 45 - 5.8. Interpreting owner and owner_group . . . . . . . . . . . 46 - 5.9. Character Case Attributes . . . . . . . . . . . . . . . 48 - 5.10. Quota Attributes . . . . . . . . . . . . . . . . . . . . 48 - 5.11. Access Control Lists . . . . . . . . . . . . . . . . . . 49 - 5.11.1. ACE type . . . . . . . . . . . . . . . . . . . . . . 50 - 5.11.2. ACE Access Mask . . . . . . . . . . . . . . . . . . . 51 - 5.11.3. ACE flag . . . . . . . . . . . . . . . . . . . . . . 53 - 5.11.4. ACE who . . . . . . . . . . . . . . . . . . . . . . . 55 - 5.11.5. Mode Attribute . . . . . . . . . . . . . . . . . . . 56 - 5.11.6. Mode and ACL Attribute . . . . . . . . . . . . . . . 57 - 5.11.7. mounted_on_fileid . . . . . . . . . . . . . . . . . . 57 - 6. Filesystem Migration and Replication . . . . . . . . . . . . 58 - 6.1. Replication . . . . . . . . . . . . . . . . . . . . . . 59 - 6.2. Migration . . . . . . . . . . . . . . . . . . . . . . . 59 - 6.3. Interpretation of the fs_locations Attribute . . . . . . 60 - 6.4. Filehandle Recovery for Migration or Replication . . . . 61 - 7. NFS Server Name Space . . . . . . . . . . . . . . . . . . . . 61 - 7.1. Server Exports . . . . . . . . . . . . . . . . . . . . . 61 - 7.2. Browsing Exports . . . . . . . . . . . . . . . . . . . . 62 - 7.3. Server Pseudo Filesystem . . . . . . . . . . . . . . . . 62 - 7.4. Multiple Roots . . . . . . . . . . . . . . . . . . . . . 63 - 7.5. Filehandle Volatility . . . . . . . . . . . . . . . . . 63 - 7.6. Exported Root . . . . . . . . . . . . . . . . . . . . . 63 - 7.7. Mount Point Crossing . . . . . . . . . . . . . . . . . . 63 - 7.8. Security Policy and Name Space Presentation . . . . . . 64 - 8. File Locking and Share Reservations . . . . . . . . . . . . . 65 - 8.1. Locking . . . . . . . . . . . . . . . . . . . . . . . . 65 - 8.1.1. Client ID . . . . . . . . . . . . . . . . . . . . . . 66 - 8.1.2. Server Release of Clientid . . . . . . . . . . . . . 69 - 8.1.3. lock_owner and stateid Definition . . . . . . . . . . 69 - 8.1.4. Use of the stateid and Locking . . . . . . . . . . . 71 - 8.1.5. Sequencing of Lock Requests . . . . . . . . . . . . . 73 - 8.1.6. Recovery from Replayed Requests . . . . . . . . . . . 74 - 8.1.7. Releasing lock_owner State . . . . . . . . . . . . . 74 - 8.1.8. Use of Open Confirmation . . . . . . . . . . . . . . 75 - 8.2. Lock Ranges . . . . . . . . . . . . . . . . . . . . . . 76 - 8.3. Upgrading and Downgrading Locks . . . . . . . . . . . . 76 - 8.4. Blocking Locks . . . . . . . . . . . . . . . . . . . . . 77 - 8.5. Lease Renewal . . . . . . . . . . . . . . . . . . . . . 77 - 8.6. Crash Recovery . . . . . . . . . . . . . . . . . . . . . 78 - 8.6.1. Client Failure and Recovery . . . . . . . . . . . . . 78 - 8.6.2. Server Failure and Recovery . . . . . . . . . . . . . 79 - 8.6.3. Network Partitions and Recovery . . . . . . . . . . . 81 - 8.7. Recovery from a Lock Request Timeout or Abort . . . . . 84 - 8.8. Server Revocation of Locks . . . . . . . . . . . . . . . 85 - 8.9. Share Reservations . . . . . . . . . . . . . . . . . . . 86 - 8.10. OPEN/CLOSE Operations . . . . . . . . . . . . . . . . . 87 - 8.10.1. Close and Retention of State Information . . . . . . 87 - 8.11. Open Upgrade and Downgrade . . . . . . . . . . . . . . . 88 - 8.12. Short and Long Leases . . . . . . . . . . . . . . . . . 89 - 8.13. Clocks, Propagation Delay, and Calculating Lease - Expiration . . . . . . . . . . . . . . . . . . . . . . . 89 - 8.14. Migration, Replication and State . . . . . . . . . . . . 90 - 8.14.1. Migration and State . . . . . . . . . . . . . . . . . 90 - 8.14.2. Replication and State . . . . . . . . . . . . . . . . 91 - 8.14.3. Notification of Migrated Lease . . . . . . . . . . . 91 - 8.14.4. Migration and the Lease_time Attribute . . . . . . . 92 - 9. Client-Side Caching . . . . . . . . . . . . . . . . . . . . . 93 - 9.1. Performance Challenges for Client-Side Caching . . . . . 93 - 9.2. Delegation and Callbacks . . . . . . . . . . . . . . . . 94 - 9.2.1. Delegation Recovery . . . . . . . . . . . . . . . . . 95 - 9.3. Data Caching . . . . . . . . . . . . . . . . . . . . . . 97 - 9.3.1. Data Caching and OPENs . . . . . . . . . . . . . . . 98 - 9.3.2. Data Caching and File Locking . . . . . . . . . . . . 99 - 9.3.3. Data Caching and Mandatory File Locking . . . . . . . 100 - 9.3.4. Data Caching and File Identity . . . . . . . . . . . 101 - 9.4. Open Delegation . . . . . . . . . . . . . . . . . . . . 102 - 9.4.1. Open Delegation and Data Caching . . . . . . . . . . 104 - 9.4.2. Open Delegation and File Locks . . . . . . . . . . . 105 - 9.4.3. Handling of CB_GETATTR . . . . . . . . . . . . . . . 106 - 9.4.4. Recall of Open Delegation . . . . . . . . . . . . . . 109 - 9.4.5. Clients that Fail to Honor Delegation Recalls . . . . 111 - 9.4.6. Delegation Revocation . . . . . . . . . . . . . . . . 111 - 9.5. Data Caching and Revocation . . . . . . . . . . . . . . 112 - 9.5.1. Revocation Recovery for Write Open Delegation . . . . 112 - 9.6. Attribute Caching . . . . . . . . . . . . . . . . . . . 113 - 9.7. Data and Metadata Caching and Memory Mapped Files . . . 115 - 9.8. Name Caching . . . . . . . . . . . . . . . . . . . . . . 117 - 9.9. Directory Caching . . . . . . . . . . . . . . . . . . . 118 - 10. Minor Versioning . . . . . . . . . . . . . . . . . . . . . . 119 - 11. Internationalization . . . . . . . . . . . . . . . . . . . . 122 - 11.1. Stringprep profile for the utf8str_cs type . . . . . . . 123 - 11.1.1. Intended applicability of the nfs4_cs_prep profile . 123 - 11.1.2. Character repertoire of nfs4_cs_prep . . . . . . . . 123 - 11.1.3. Mapping used by nfs4_cs_prep . . . . . . . . . . . . 123 - 11.1.4. Normalization used by nfs4_cs_prep . . . . . . . . . 124 - 11.1.5. Prohibited output for nfs4_cs_prep . . . . . . . . . 124 - 11.1.6. Bidirectional output for nfs4_cs_prep . . . . . . . . 124 - 11.2. Stringprep profile for the utf8str_cis type . . . . . . 124 - 11.2.1. Intended applicability of the nfs4_cis_prep profile . 125 - 11.2.2. Character repertoire of nfs4_cis_prep . . . . . . . . 125 - 11.2.3. Mapping used by nfs4_cis_prep . . . . . . . . . . . . 125 - 11.2.4. Normalization used by nfs4_cis_prep . . . . . . . . . 125 - 11.2.5. Prohibited output for nfs4_cis_prep . . . . . . . . . 125 - 11.2.6. Bidirectional output for nfs4_cis_prep . . . . . . . 126 - 11.3. Stringprep profile for the utf8str_mixed type . . . . . 126 - 11.3.1. Intended applicability of the nfs4_mixed_prep - profile . . . . . . . . . . . . . . . . . . . . . . . 126 - 11.3.2. Character repertoire of nfs4_mixed_prep . . . . . . . 126 - 11.3.3. Mapping used by nfs4_cis_prep . . . . . . . . . . . . 126 - 11.3.4. Normalization used by nfs4_mixed_prep . . . . . . . . 126 - 11.3.5. Prohibited output for nfs4_mixed_prep . . . . . . . . 126 - 11.3.6. Bidirectional output for nfs4_mixed_prep . . . . . . 127 - 11.4. UTF-8 Related Errors . . . . . . . . . . . . . . . . . . 127 - 12. Error Definitions . . . . . . . . . . . . . . . . . . . . . . 128 - 13. NFS version 4 Requests . . . . . . . . . . . . . . . . . . . 133 - 13.1. Compound Procedure . . . . . . . . . . . . . . . . . . . 133 - 13.2. Evaluation of a Compound Request . . . . . . . . . . . . 134 - 13.3. Synchronous Modifying Operations . . . . . . . . . . . . 135 - 13.4. Operation Values . . . . . . . . . . . . . . . . . . . . 135 - 14. NFS version 4 Procedures . . . . . . . . . . . . . . . . . . 135 - 14.1. Procedure 0: NULL - No Operation . . . . . . . . . . . . 135 - 14.2. Procedure 1: COMPOUND - Compound Operations . . . . . . 136 - 14.3. Operation 3: ACCESS - Check Access Rights . . . . . . . 139 - 14.4. Operation 4: CLOSE - Close File . . . . . . . . . . . . 142 - 14.5. Operation 5: COMMIT - Commit Cached Data . . . . . . . . 143 - 14.6. Operation 6: CREATE - Create a Non-Regular File Object . 146 - 14.7. Operation 7: DELEGPURGE - Purge Delegations Awaiting - Recovery . . . . . . . . . . . . . . . . . . . . . . . . 149 - 14.8. Operation 8: DELEGRETURN - Return Delegation . . . . . . 150 - 14.9. Operation 9: GETATTR - Get Attributes . . . . . . . . . 151 - 14.10. Operation 10: GETFH - Get Current Filehandle . . . . . . 153 - 14.11. Operation 11: LINK - Create Link to a File . . . . . . . 154 - 14.12. Operation 12: LOCK - Create Lock . . . . . . . . . . . . 156 - 14.13. Operation 13: LOCKT - Test For Lock . . . . . . . . . . 160 - 14.14. Operation 14: LOCKU - Unlock File . . . . . . . . . . . 162 - 14.15. Operation 15: LOOKUP - Lookup Filename . . . . . . . . . 164 - 14.16. Operation 16: LOOKUPP - Lookup Parent Directory . . . . 166 - 14.17. Operation 17: NVERIFY - Verify Difference in - Attributes . . . . . . . . . . . . . . . . . . . . . . . 167 - 14.18. Operation 18: OPEN - Open a Regular File . . . . . . . . 169 - 14.19. Operation 19: OPENATTR - Open Named Attribute - Directory . . . . . . . . . . . . . . . . . . . . . . . 179 - 14.20. Operation 20: OPEN_CONFIRM - Confirm Open . . . . . . . 181 - 14.21. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access . 184 - 14.22. Operation 22: PUTFH - Set Current Filehandle . . . . . . 185 - 14.23. Operation 23: PUTPUBFH - Set Public Filehandle . . . . . 186 - 14.24. Operation 24: PUTROOTFH - Set Root Filehandle . . . . . 188 - 14.25. Operation 25: READ - Read from File . . . . . . . . . . 188 - 14.26. Operation 26: READDIR - Read Directory . . . . . . . . . 191 - 14.27. Operation 27: READLINK - Read Symbolic Link . . . . . . 195 - 14.28. Operation 28: REMOVE - Remove Filesystem Object . . . . 196 - 14.29. Operation 29: RENAME - Rename Directory Entry . . . . . 199 - 14.30. Operation 30: RENEW - Renew a Lease . . . . . . . . . . 202 - 14.31. Operation 31: RESTOREFH - Restore Saved Filehandle . . . 204 - 14.32. Operation 32: SAVEFH - Save Current Filehandle . . . . . 205 - 14.33. Operation 33: SECINFO - Obtain Available Security . . . 206 - 14.34. Operation 34: SETATTR - Set Attributes . . . . . . . . . 210 - 14.35. Operation 35: SETCLIENTID - Negotiate Clientid . . . . . 213 - 14.36. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid . . 216 - 14.37. Operation 37: VERIFY - Verify Same Attributes . . . . . 220 - 14.38. Operation 38: WRITE - Write to File . . . . . . . . . . 222 - 14.39. Operation 39: RELEASE_LOCKOWNER - Release Lockowner - State . . . . . . . . . . . . . . . . . . . . . . . . . 226 - 14.40. Operation 10044: ILLEGAL - Illegal operation . . . . . . 228 - 15. NFS version 4 Callback Procedures . . . . . . . . . . . . . . 228 - 15.1. Procedure 0: CB_NULL - No Operation . . . . . . . . . . 229 - 15.2. Procedure 1: CB_COMPOUND - Compound Operations . . . . . 229 - 15.2.7. Operation 3: CB_GETATTR - Get Attributes . . . . . . 231 - 15.2.8. Operation 4: CB_RECALL - Recall an Open Delegation . 232 - 15.2.9. Operation 10044: CB_ILLEGAL - Illegal Callback - Operation . . . . . . . . . . . . . . . . . . . . . . 234 - 16. Security Considerations . . . . . . . . . . . . . . . . . . . 234 - 17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 236 - 17.1. Named Attribute Definition . . . . . . . . . . . . . . . 236 - 17.2. ONC RPC Network Identifiers (netids) . . . . . . . . . . 236 - 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 238 - 18.1. Normative References . . . . . . . . . . . . . . . . . . 238 - 18.2. Informative References . . . . . . . . . . . . . . . . . 238 - Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 240 - Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 240 - Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 240 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 8 + 1.1. Changes since RFC 3530 . . . . . . . . . . . . . . . . . 8 + 1.2. Changes since RFC 3010 . . . . . . . . . . . . . . . . . 8 + 1.3. NFS Version 4 Goals . . . . . . . . . . . . . . . . . . 10 + 1.4. Inconsistencies of this Document with the companion + document NFS Version 4 Protocol . . . . . . . . . . . . 10 + 1.5. Overview of NFS version 4 Features . . . . . . . . . . . 11 + 1.5.1. RPC and Security . . . . . . . . . . . . . . . . . . 11 + 1.5.2. Procedure and Operation Structure . . . . . . . . . 11 + 1.5.3. Filesystem Model . . . . . . . . . . . . . . . . . . 12 + 1.5.4. OPEN and CLOSE . . . . . . . . . . . . . . . . . . . 14 + 1.5.5. File Locking . . . . . . . . . . . . . . . . . . . . 14 + 1.5.6. Client Caching and Delegation . . . . . . . . . . . 14 + 1.6. General Definitions . . . . . . . . . . . . . . . . . . 15 + 2. Protocol Data Types . . . . . . . . . . . . . . . . . . . . . 17 + 2.1. Basic Data Types . . . . . . . . . . . . . . . . . . . . 17 + 2.2. Structured Data Types . . . . . . . . . . . . . . . . . 18 + 3. RPC and Security Flavor . . . . . . . . . . . . . . . . . . . 24 + 3.1. Ports and Transports . . . . . . . . . . . . . . . . . . 24 + 3.1.1. Client Retransmission Behavior . . . . . . . . . . . 25 + 3.2. Security Flavors . . . . . . . . . . . . . . . . . . . . 25 + 3.2.1. Security mechanisms for NFS version 4 . . . . . . . 26 + 3.3. Security Negotiation . . . . . . . . . . . . . . . . . . 28 + 3.3.1. SECINFO . . . . . . . . . . . . . . . . . . . . . . 28 + 3.3.2. Security Error . . . . . . . . . . . . . . . . . . . 28 + 3.3.3. Callback RPC Authentication . . . . . . . . . . . . 29 + 4. Filehandles . . . . . . . . . . . . . . . . . . . . . . . . . 31 + 4.1. Obtaining the First Filehandle . . . . . . . . . . . . . 31 + 4.1.1. Root Filehandle . . . . . . . . . . . . . . . . . . 31 + 4.1.2. Public Filehandle . . . . . . . . . . . . . . . . . 31 + 4.2. Filehandle Types . . . . . . . . . . . . . . . . . . . . 32 + 4.2.1. General Properties of a Filehandle . . . . . . . . . 32 + 4.2.2. Persistent Filehandle . . . . . . . . . . . . . . . 33 + 4.2.3. Volatile Filehandle . . . . . . . . . . . . . . . . 33 + 4.2.4. One Method of Constructing a Volatile Filehandle . . 35 + 4.3. Client Recovery from Filehandle Expiration . . . . . . . 35 + 5. File Attributes . . . . . . . . . . . . . . . . . . . . . . . 36 + 5.1. REQUIRED Attributes . . . . . . . . . . . . . . . . . . 37 + 5.2. RECOMMENDED Attributes . . . . . . . . . . . . . . . . . 37 + 5.3. Named Attributes . . . . . . . . . . . . . . . . . . . . 38 + 5.4. Classification of Attributes . . . . . . . . . . . . . . 39 + 5.5. Set-Only and Get-Only Attributes . . . . . . . . . . . . 40 + 5.6. REQUIRED Attributes - List and Definition References . . 40 + 5.7. RECOMMENDED Attributes - List and Definition + References . . . . . . . . . . . . . . . . . . . . . . . 41 + 5.8. Attribute Definitions . . . . . . . . . . . . . . . . . 42 + 5.8.1. Definitions of REQUIRED Attributes . . . . . . . . . 42 + 5.8.2. Definitions of Uncategorized RECOMMENDED + Attributes . . . . . . . . . . . . . . . . . . . . . 44 + 5.9. Interpreting owner and owner_group . . . . . . . . . . . 50 + 5.10. Character Case Attributes . . . . . . . . . . . . . . . 52 + 6. Access Control Attributes . . . . . . . . . . . . . . . . . . 53 + 6.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . 53 + 6.2. File Attributes Discussion . . . . . . . . . . . . . . . 54 + 6.2.1. Attribute 12: acl . . . . . . . . . . . . . . . . . 54 + 6.2.2. Attribute 33: mode . . . . . . . . . . . . . . . . . 68 + 6.3. Common Methods . . . . . . . . . . . . . . . . . . . . . 68 + 6.3.1. Interpreting an ACL . . . . . . . . . . . . . . . . 68 + 6.3.2. Computing a Mode Attribute from an ACL . . . . . . . 69 + 6.4. Requirements . . . . . . . . . . . . . . . . . . . . . . 70 + 6.4.1. Setting the mode and/or ACL Attributes . . . . . . . 71 + 6.4.2. Retrieving the mode and/or ACL Attributes . . . . . 72 + 6.4.3. Creating New Objects . . . . . . . . . . . . . . . . 72 + 7. Multi-Server Namespace . . . . . . . . . . . . . . . . . . . 74 + 7.1. Location Attributes . . . . . . . . . . . . . . . . . . 74 + 7.2. File System Presence or Absence . . . . . . . . . . . . 75 + 7.3. Getting Attributes for an Absent File System . . . . . . 76 + 7.3.1. GETATTR Within an Absent File System . . . . . . . . 76 + 7.3.2. READDIR and Absent File Systems . . . . . . . . . . 77 + 7.4. Uses of Location Information . . . . . . . . . . . . . . 78 + 7.4.1. File System Replication . . . . . . . . . . . . . . 78 + 7.4.2. File System Migration . . . . . . . . . . . . . . . 79 + 7.4.3. Referrals . . . . . . . . . . . . . . . . . . . . . 80 + 7.5. Location Entries and Server Identity . . . . . . . . . . 80 + 7.6. Additional Client-side Considerations . . . . . . . . . 81 + 7.7. Effecting File System Transitions . . . . . . . . . . . 82 + 7.7.1. File System Transitions and Simultaneous Access . . 83 + 7.7.2. Filehandles and File System Transitions . . . . . . 83 + 7.7.3. Fileids and File System Transitions . . . . . . . . 84 + 7.7.4. Fsids and File System Transitions . . . . . . . . . 85 + 7.7.5. The Change Attribute and File System Transitions . . 85 + 7.7.6. Lock State and File System Transitions . . . . . . . 86 + 7.7.7. Write Verifiers and File System Transitions . . . . 88 + 7.7.8. Readdir Cookies and Verifiers and File System + Transitions . . . . . . . . . . . . . . . . . . . . 88 + 7.7.9. File System Data and File System Transitions . . . . 88 + 7.8. Effecting File System Referrals . . . . . . . . . . . . 90 + 7.8.1. Referral Example (LOOKUP) . . . . . . . . . . . . . 90 + 7.8.2. Referral Example (READDIR) . . . . . . . . . . . . . 94 + 7.9. The Attribute fs_locations . . . . . . . . . . . . . . . 97 + 7.9.1. Inferring Transition Modes . . . . . . . . . . . . . 98 + 8. NFS Server Name Space . . . . . . . . . . . . . . . . . . . . 99 + 8.1. Server Exports . . . . . . . . . . . . . . . . . . . . . 100 + 8.2. Browsing Exports . . . . . . . . . . . . . . . . . . . . 100 + 8.3. Server Pseudo Filesystem . . . . . . . . . . . . . . . . 100 + 8.4. Multiple Roots . . . . . . . . . . . . . . . . . . . . . 101 + 8.5. Filehandle Volatility . . . . . . . . . . . . . . . . . 101 + 8.6. Exported Root . . . . . . . . . . . . . . . . . . . . . 101 + 8.7. Mount Point Crossing . . . . . . . . . . . . . . . . . . 102 + 8.8. Security Policy and Name Space Presentation . . . . . . 102 + 9. File Locking and Share Reservations . . . . . . . . . . . . . 103 + 9.1. Locking . . . . . . . . . . . . . . . . . . . . . . . . 104 + 9.1.1. Client ID . . . . . . . . . . . . . . . . . . . . . 104 + 9.1.2. Server Release of Clientid . . . . . . . . . . . . . 107 + 9.1.3. lock_owner and stateid Definition . . . . . . . . . 107 + 9.1.4. Use of the stateid and Locking . . . . . . . . . . . 109 + 9.1.5. Sequencing of Lock Requests . . . . . . . . . . . . 111 + 9.1.6. Recovery from Replayed Requests . . . . . . . . . . 112 + 9.1.7. Releasing lock_owner State . . . . . . . . . . . . . 112 + 9.1.8. Use of Open Confirmation . . . . . . . . . . . . . . 113 + 9.2. Lock Ranges . . . . . . . . . . . . . . . . . . . . . . 114 + 9.3. Upgrading and Downgrading Locks . . . . . . . . . . . . 114 + 9.4. Blocking Locks . . . . . . . . . . . . . . . . . . . . . 115 + 9.5. Lease Renewal . . . . . . . . . . . . . . . . . . . . . 115 + 9.6. Crash Recovery . . . . . . . . . . . . . . . . . . . . . 116 + 9.6.1. Client Failure and Recovery . . . . . . . . . . . . 117 + 9.6.2. Server Failure and Recovery . . . . . . . . . . . . 117 + 9.6.3. Network Partitions and Recovery . . . . . . . . . . 119 + 9.7. Recovery from a Lock Request Timeout or Abort . . . . . 122 + 9.8. Server Revocation of Locks . . . . . . . . . . . . . . . 123 + 9.9. Share Reservations . . . . . . . . . . . . . . . . . . . 124 + 9.10. OPEN/CLOSE Operations . . . . . . . . . . . . . . . . . 125 + 9.10.1. Close and Retention of State Information . . . . . . 125 + 9.11. Open Upgrade and Downgrade . . . . . . . . . . . . . . . 126 + 9.12. Short and Long Leases . . . . . . . . . . . . . . . . . 127 + 9.13. Clocks, Propagation Delay, and Calculating Lease + Expiration . . . . . . . . . . . . . . . . . . . . . . . 127 + 9.14. Migration, Replication and State . . . . . . . . . . . . 128 + 9.14.1. Migration and State . . . . . . . . . . . . . . . . 128 + 9.14.2. Replication and State . . . . . . . . . . . . . . . 129 + 9.14.3. Notification of Migrated Lease . . . . . . . . . . . 129 + 9.14.4. Migration and the Lease_time Attribute . . . . . . . 130 + 10. Client-Side Caching . . . . . . . . . . . . . . . . . . . . . 131 + 10.1. Performance Challenges for Client-Side Caching . . . . . 131 + 10.2. Delegation and Callbacks . . . . . . . . . . . . . . . . 132 + 10.2.1. Delegation Recovery . . . . . . . . . . . . . . . . 133 + 10.3. Data Caching . . . . . . . . . . . . . . . . . . . . . . 135 + 10.3.1. Data Caching and OPENs . . . . . . . . . . . . . . . 136 + 10.3.2. Data Caching and File Locking . . . . . . . . . . . 137 + 10.3.3. Data Caching and Mandatory File Locking . . . . . . 138 + 10.3.4. Data Caching and File Identity . . . . . . . . . . . 139 + 10.4. Open Delegation . . . . . . . . . . . . . . . . . . . . 140 + 10.4.1. Open Delegation and Data Caching . . . . . . . . . . 142 + 10.4.2. Open Delegation and File Locks . . . . . . . . . . . 143 + 10.4.3. Handling of CB_GETATTR . . . . . . . . . . . . . . . 144 + 10.4.4. Recall of Open Delegation . . . . . . . . . . . . . 147 + 10.4.5. Clients that Fail to Honor Delegation Recalls . . . 149 + 10.4.6. Delegation Revocation . . . . . . . . . . . . . . . 149 + 10.5. Data Caching and Revocation . . . . . . . . . . . . . . 150 + 10.5.1. Revocation Recovery for Write Open Delegation . . . 150 + 10.6. Attribute Caching . . . . . . . . . . . . . . . . . . . 151 + 10.7. Data and Metadata Caching and Memory Mapped Files . . . 153 + 10.8. Name Caching . . . . . . . . . . . . . . . . . . . . . . 155 + 10.9. Directory Caching . . . . . . . . . . . . . . . . . . . 156 + 11. Minor Versioning . . . . . . . . . . . . . . . . . . . . . . 157 + 12. Internationalization . . . . . . . . . . . . . . . . . . . . 160 + 12.1. Use of UTF-8 . . . . . . . . . . . . . . . . . . . . . . 161 + 12.1.1. Relation to Stringprep . . . . . . . . . . . . . . . 161 + 12.1.2. Normalization, Equivalence, and Confusability . . . 162 + 12.2. String Type Overview . . . . . . . . . . . . . . . . . . 164 + 12.2.1. Overall String Class Divisions . . . . . . . . . . . 164 + 12.2.2. Divisions by Typedef Parent types . . . . . . . . . 165 + 12.2.3. Individual Types and Their Handling . . . . . . . . 166 + 12.3. Errors Related to Strings . . . . . . . . . . . . . . . 167 + 12.4. Types with Pre-processing to Resolve Mixture Issues . . 168 + 12.4.1. Processing of Principal Strings . . . . . . . . . . 168 + 12.4.2. Processing of Server Id Strings . . . . . . . . . . 168 + 12.5. String Types without Internationalization Processing . . 169 + 12.6. Types with Processing Defined by Other Internet Areas . 169 + 12.7. String Types with NFS-specific Processing . . . . . . . 170 + 12.7.1. Handling of File Came Components . . . . . . . . . . 171 + 12.7.2. Processing of Link Text . . . . . . . . . . . . . . 178 + 12.7.3. Processing of Principal Prefixes . . . . . . . . . . 179 + 13. Error Values . . . . . . . . . . . . . . . . . . . . . . . . 179 + 13.1. Error Definitions . . . . . . . . . . . . . . . . . . . 180 + 13.1.1. General Errors . . . . . . . . . . . . . . . . . . . 181 + 13.1.2. Filehandle Errors . . . . . . . . . . . . . . . . . 183 + 13.1.3. Compound Structure Errors . . . . . . . . . . . . . 184 + 13.1.4. File System Errors . . . . . . . . . . . . . . . . . 185 + 13.1.5. State Management Errors . . . . . . . . . . . . . . 187 + 13.1.6. Security Errors . . . . . . . . . . . . . . . . . . 188 + 13.1.7. Name Errors . . . . . . . . . . . . . . . . . . . . 188 + 13.1.8. Locking Errors . . . . . . . . . . . . . . . . . . . 189 + 13.1.9. Reclaim Errors . . . . . . . . . . . . . . . . . . . 190 + 13.1.10. Client Management Errors . . . . . . . . . . . . . . 191 + 13.1.11. Attribute Handling Errors . . . . . . . . . . . . . 191 + 13.2. Operations and their valid errors . . . . . . . . . . . 192 + 13.3. Callback operations and their valid errors . . . . . . . 199 + 13.4. Errors and the operations that use them . . . . . . . . 199 + 14. NFS version 4 Requests . . . . . . . . . . . . . . . . . . . 204 + 14.1. Compound Procedure . . . . . . . . . . . . . . . . . . . 204 + 14.2. Evaluation of a Compound Request . . . . . . . . . . . . 205 + 14.3. Synchronous Modifying Operations . . . . . . . . . . . . 206 + 14.4. Operation Values . . . . . . . . . . . . . . . . . . . . 206 + 15. NFS version 4 Procedures . . . . . . . . . . . . . . . . . . 206 + 15.1. Procedure 0: NULL - No Operation . . . . . . . . . . . . 206 + 15.2. Procedure 1: COMPOUND - Compound Operations . . . . . . 207 + 15.3. Operation 3: ACCESS - Check Access Rights . . . . . . . 209 + 15.4. Operation 4: CLOSE - Close File . . . . . . . . . . . . 212 + 15.5. Operation 5: COMMIT - Commit Cached Data . . . . . . . . 213 + 15.6. Operation 6: CREATE - Create a Non-Regular File Object . 216 + 15.7. Operation 7: DELEGPURGE - Purge Delegations Awaiting + Recovery . . . . . . . . . . . . . . . . . . . . . . . . 218 + 15.8. Operation 8: DELEGRETURN - Return Delegation . . . . . . 219 + 15.9. Operation 9: GETATTR - Get Attributes . . . . . . . . . 220 + 15.10. Operation 10: GETFH - Get Current Filehandle . . . . . . 221 + 15.11. Operation 11: LINK - Create Link to a File . . . . . . . 222 + 15.12. Operation 12: LOCK - Create Lock . . . . . . . . . . . . 224 + 15.13. Operation 13: LOCKT - Test For Lock . . . . . . . . . . 228 + 15.14. Operation 14: LOCKU - Unlock File . . . . . . . . . . . 229 + 15.15. Operation 15: LOOKUP - Lookup Filename . . . . . . . . . 230 + 15.16. Operation 16: LOOKUPP - Lookup Parent Directory . . . . 232 + 15.17. Operation 17: NVERIFY - Verify Difference in + Attributes . . . . . . . . . . . . . . . . . . . . . . . 233 + 15.18. Operation 18: OPEN - Open a Regular File . . . . . . . . 234 + 15.19. Operation 19: OPENATTR - Open Named Attribute + Directory . . . . . . . . . . . . . . . . . . . . . . . 243 + 15.20. Operation 20: OPEN_CONFIRM - Confirm Open . . . . . . . 244 + 15.21. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access . 246 + 15.22. Operation 22: PUTFH - Set Current Filehandle . . . . . . 248 + 15.23. Operation 23: PUTPUBFH - Set Public Filehandle . . . . . 248 + 15.24. Operation 24: PUTROOTFH - Set Root Filehandle . . . . . 250 + 15.25. Operation 25: READ - Read from File . . . . . . . . . . 250 + 15.26. Operation 26: READDIR - Read Directory . . . . . . . . . 252 + 15.27. Operation 27: READLINK - Read Symbolic Link . . . . . . 256 + 15.28. Operation 28: REMOVE - Remove Filesystem Object . . . . 257 + 15.29. Operation 29: RENAME - Rename Directory Entry . . . . . 259 + 15.30. Operation 30: RENEW - Renew a Lease . . . . . . . . . . 261 + 15.31. Operation 31: RESTOREFH - Restore Saved Filehandle . . . 262 + 15.32. Operation 32: SAVEFH - Save Current Filehandle . . . . . 263 + 15.33. Operation 33: SECINFO - Obtain Available Security . . . 263 + 15.34. Operation 34: SETATTR - Set Attributes . . . . . . . . . 266 + 15.35. Operation 35: SETCLIENTID - Negotiate Clientid . . . . . 269 + 15.36. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid . . 272 + 15.37. Operation 37: VERIFY - Verify Same Attributes . . . . . 276 + 15.38. Operation 38: WRITE - Write to File . . . . . . . . . . 277 + 15.39. Operation 39: RELEASE_LOCKOWNER - Release Lockowner + State . . . . . . . . . . . . . . . . . . . . . . . . . 281 + + 15.40. Operation 10044: ILLEGAL - Illegal operation . . . . . . 282 + 16. NFS version 4 Callback Procedures . . . . . . . . . . . . . . 283 + 16.1. Procedure 0: CB_NULL - No Operation . . . . . . . . . . 283 + 16.2. Procedure 1: CB_COMPOUND - Compound Operations . . . . . 284 + 16.2.6. Operation 3: CB_GETATTR - Get Attributes . . . . . . 285 + 16.2.7. Operation 4: CB_RECALL - Recall an Open Delegation . 286 + 16.2.8. Operation 10044: CB_ILLEGAL - Illegal Callback + Operation . . . . . . . . . . . . . . . . . . . . . 287 + 17. Security Considerations . . . . . . . . . . . . . . . . . . . 288 + 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 290 + 18.1. Named Attribute Definition . . . . . . . . . . . . . . . 290 + 18.2. ONC RPC Network Identifiers (netids) . . . . . . . . . . 290 + 19. References . . . . . . . . . . . . . . . . . . . . . . . . . 291 + 19.1. Normative References . . . . . . . . . . . . . . . . . . 291 + 19.2. Informative References . . . . . . . . . . . . . . . . . 292 + Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 294 + Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 294 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 294 1. Introduction 1.1. Changes since RFC 3530 - This document obsoletes RFC 3530 [10] as the authoritative document - describing NFSv4, without introducing any over-the-wire protocol - changes. The main changes from RFC 3530 are: + This document, together with the companion XDR description document + [2], obsoletes RFC 3530 [11] as the authoritative document describing + NFSv4. It does not introduce any over-the-wire protocol changes, in + the sense that previously valid requests requests remain valid. + However, some requests previously defined as invalid, although not + generally rejected, are now explicitly allowed, in that + internationalization handling has been generalized and liberalized. + The main changes from RFC 3530 are: - o The RPC definition has been moved to a companion document [2] + o The XDR definition has been moved to a companion document [2] o Updates for the latest IETF intellectual property statements + o There is a restructured and more complete explanation of multi- + server namespace features. In particular, this explanation + explicitly describes handling of inter-server referrals, even + where neither migration nor replication is involved. + + o More liberal handling of internationalization for file names and + user and group names, with the elimination of restrictions imposed + by stringprep, with the recognition that rules for the forms of + these name are the province of the receiving entity. + + o Updating handling of domain names to reflect IDNA. + + o Restructuring of string types to more appropriately reflect the + reality of required string processing. + o LIPKEY SPKM/3 has been moved from being mandatory to optional o Some clarification on a client re-establishing callback information to the new server if state has been migrated 1.2. Changes since RFC 3010 This definition of the NFS version 4 protocol replaces or obsoletes - the definition present in [11]. While portions of the two documents + the definition present in [12]. While portions of the two documents have remained the same, there have been substantive changes in - others. The changes made between [11] and this document represent + others. The changes made between [12] and this document represent implementation experience and further review of the protocol. While some modifications were made for ease of implementation or clarification, most updates represent errors or situations where the - [11] definition were untenable. + [12] definition were untenable. The following list is not all inclusive of all changes but presents some of the most notable changes or additions made: o The state model has added an open_owner4 identifier. This was done to accommodate Posix based clients and the model they use for file locking. For Posix clients, an open_owner4 would correspond to a file descriptor potentially shared amongst a set of processes and the lock_owner4 identifier would correspond to a process that is locking a file. @@ -363,21 +427,21 @@ o Remove use of the pathname4 data type from LOOKUP and OPEN in favor of having the client construct a sequence of LOOKUP operations to achieive the same effect. o Clarification of the internationalization issues and adoption of the new stringprep profile framework. 1.3. NFS Version 4 Goals The NFS version 4 protocol is a further revision of the NFS protocol - defined already by versions 2 [12] and 3 [13]. It retains the + defined already by versions 2 [13] and 3 [14]. It retains the essential characteristics of previous versions: design for easy recovery, independent of transport protocols, operating systems and filesystems, simplicity, and good performance. The NFS version 4 revision has the following goals: o Improved access and good performance on the Internet. The protocol is designed to transit firewalls easily, perform well where latency is high and bandwidth is low, and scale to very large numbers of clients per server. @@ -394,52 +458,53 @@ The protocol features a filesystem model that provides a useful, common set of features that does not unduly favor one filesystem or operating system over another. o Designed for protocol extensions. The protocol is designed to accept standard extensions that do not compromise backward compatibility. -1.4. Inconsistencies of this Document with Section 18 +1.4. Inconsistencies of this Document with the companion document NFS + Version 4 Protocol - Section 18, RPC Definition File, contains the definitions in XDR - description language of the constructs used by the protocol. Prior - to Section 18, several of the constructs are reproduced for purposes + [2], NFS Version 4 Protocol, contains the definitions in XDR + description language of the constructs used by the protocol. Inside + this document, several of the constructs are reproduced for purposes of explanation. The reader is warned of the possibility of errors in - the reproduced constructs outside of Section 18. For any part of the - document that is inconsistent with Section 18, Section 18 is to be - considered authoritative. + the reproduced constructs outside of [2]. For any part of the + document that is inconsistent with [2], [2] is to be considered + authoritative. 1.5. Overview of NFS version 4 Features To provide a reasonable context for the reader, the major features of NFS version 4 protocol will be reviewed in brief. This will be done to provide an appropriate context for both the reader who is familiar with the previous versions of the NFS protocol and the reader that is new to the NFS protocols. For the reader new to the NFS protocols, there is still a fundamental knowledge that is expected. The reader should be familiar with the XDR and RPC protocols as described in [3] - and [14]. A basic knowledge of filesystems and distributed + and [15]. A basic knowledge of filesystems and distributed filesystems is expected as well. 1.5.1. RPC and Security As with previous versions of NFS, the External Data Representation (XDR) and Remote Procedure Call (RPC) mechanisms used for the NFS - version 4 protocol are those defined in [3] and [14]. To meet end to + version 4 protocol are those defined in [3] and [15]. To meet end to end security requirements, the RPCSEC_GSS framework [4] will be used to extend the basic RPC security. With the use of RPCSEC_GSS, various mechanisms can be provided to offer authentication, integrity, and privacy to the NFS version 4 protocol. Kerberos V5 - will be used as described in [15] to provide one security framework. + will be used as described in [16] to provide one security framework. The LIPKEY GSS-API mechanism described in [5] will be used to provide for the use of user password and server public key by the NFS version 4 protocol. With the use of RPCSEC_GSS, other mechanisms may also be specified and used for NFS version 4 security. To enable in-band security negotiation, the NFS version 4 protocol has added a new operation which provides the client a method of querying the server about its policies regarding which security mechanisms must be used for access to the server's filesystem resources. With this, the client can securely match the security @@ -541,39 +606,46 @@ application specific data with a regular file or directory. One significant addition to the recommended set of file attributes is the Access Control List (ACL) attribute. This attribute provides for directory and file access control beyond the model used in previous versions of the NFS protocol. The ACL definition allows for specification of user and group level access control. 1.5.3.3. Filesystem Replication and Migration - With the use of a special file attribute, the ability to migrate or - replicate server filesystems is enabled within the protocol. The + With the use of a special file attribute, the ability to inform the + client of filesystem locations on another server is enabled. The filesystem locations attribute provides a method for the client to - probe the server about the location of a filesystem. In the event of - a migration of a filesystem, the client will receive an error when - operating on the filesystem and it can then query as to the new file - system location. Similar steps are used for replication, the client - is able to query the server for the multiple available locations of a - particular filesystem. From this information, the client can use its - own policies to access the appropriate filesystem location. + probe the server about the location of a filesystem. In the event + that a fileystems is not present on server the client will receive an + error when attempting to operate on the filesystem and it can then + query as to the correct filesystem location. Thus is allowed + construction of multi-server namespaces.. + + These features also allow file system replication and migration. In + the event of a migration of a filesystem, the client will receive an + error when operating on the filesystem and it can then query location + attribute to determine the new file system location. Similar steps + are used for replication, the client is able to query the server for + the multiple available locations of a particular filesystem. From + this information, the client can use its own policies to access the + appropriate filesystem location. 1.5.4. OPEN and CLOSE The NFS version 4 protocol introduces OPEN and CLOSE operations. The OPEN operation provides a single point where file lookup, creation, and share semantics can be combined. The CLOSE operation also provides for the release of state accumulated by OPEN. -1.5.5. File locking +1.5.5. File Locking With the NFS version 4 protocol, the support for byte range file locking is part of the NFS protocol. The file locking support is structured so that an RPC callback mechanism is not required. This is a departure from the previous versions of the NFS file locking protocol, Network Lock Manager (NLM). The state associated with file locks is maintained at the server under a lease-based model. The server defines a single lease period for all state held by a NFS client. If the client does not renew its lease within the defined period, all state associated with the client's lease may be released @@ -690,31 +762,31 @@ Stateids composed of all bits 0 or all bits 1 have special meaning and are reserved values. Verifier A 64-bit quantity generated by the client that the server can use to determine if the client has restarted and lost all previous lock state. 2. Protocol Data Types The syntax and semantics to describe the data types of the NFS - version 4 protocol are defined in the XDR [14] and RPC [3] documents. + version 4 protocol are defined in the XDR [15] and RPC [3] documents. The next sections build upon the XDR data types to define types and structures specific to this protocol. 2.1. Basic Data Types These are the base NFSv4 data types. - +---------------+---------------------------------------------------+ + +----------------+--------------------------------------------------+ | Data Type | Definition | - +---------------+---------------------------------------------------+ + +----------------+--------------------------------------------------+ | int32_t | typedef int int32_t; | | uint32_t | typedef unsigned int uint32_t; | | int64_t | typedef hyper int64_t; | | uint64_t | typedef unsigned hyper uint64_t; | | attrlist4 | typedef opaque attrlist4<>; | | | Used for file/directory attributes. | | bitmap4 | typedef uint32_t bitmap4<>; | | | Used in attribute array encoding. | | changeid4 | typedef uint64_t changeid4; | | | Used in the definition of change_info4. | @@ -734,54 +806,58 @@ | | Various defined file types. | | nfsstat4 | enum nfsstat4; | | | Return value for operations. | | offset4 | typedef uint64_t offset4; | | | Various offset designations (READ, WRITE, LOCK, | | | COMMIT). | | qop4 | typedef uint32_t qop4; | | | Quality of protection designation in SECINFO. | | sec_oid4 | typedef opaque sec_oid4<>; | | | Security Object Identifier. The sec_oid4 data | - | | type is not really opaque. Instead it contains an | - | | ASN.1 OBJECT IDENTIFIER as used by GSS-API in the | - | | mech_type argument to GSS_Init_sec_context. See | - | | [6] for details. | + | | type is not really opaque. Instead it contains | + | | an ASN.1 OBJECT IDENTIFIER as used by GSS-API in | + | | the mech_type argument to GSS_Init_sec_context. | + | | See [6] for details. | | seqid4 | typedef uint32_t seqid4; | | | Sequence identifier used for file locking. | | utf8string | typedef opaque utf8string<>; | | | UTF-8 encoding for strings. | - | utf8str_cis | typedef utf8string utf8str_cis; | - | | Case-insensitive UTF-8 string. | - | utf8str_cs | typedef utf8string utf8str_cs; | - | | Case-sensitive UTF-8 string. | - | utf8str_mixed | typedef utf8string utf8str_mixed; | - | | UTF-8 strings with a case sensitive prefix and a | - | | case insensitive suffix. | - | component4 | typedef utf8str_cs component4; | + | utf8_should | typedef utf8string utf8_should; | + | | String expected to be UTF8 but no validation | + | utf8val_should | typedef utf8string utf8val_should; | + | | String SHOULD be sent UTF8 and SHOULD be | + | | validated | + | utf8val_must | typedef utf8string utf8val_must; | + | | String MUST be sent UTF8 and MUST be validated | + | ascii_must | typedef utf8string ascii_must; | + | | String MUST be sent as ASCII and thus is | + | | automatically UTF8 | + | comptag4 | typedef utf8_should comptag4; | + | | Tag should be UTF8 but is not checked | + | component4 | typedef utf8val_should component4; | | | Represents path name components. | - | linktext4 | typedef utf8str_cs linktext4; | + | linktext4 | typedef utf8val_should linktext4; | | | Symbolic link contents. | | pathname4 | typedef component4 pathname4<>; | | | Represents path name for fs_locations. | | nfs_lockid4 | typedef uint64_t nfs_lockid4; | | verifier4 | typedef opaque verifier4[NFS4_VERIFIER_SIZE]; | | | Verifier used for various operations (COMMIT, | | | CREATE, EXCHANGE_ID, OPEN, READDIR, WRITE) | | | NFS4_VERIFIER_SIZE is defined as 8. | - +---------------+---------------------------------------------------+ + +----------------+--------------------------------------------------+ End of Base Data Types Table 1 2.2. Structured Data Types - 2.2.1. nfstime4 struct nfstime4 { int64_t seconds; uint32_t nseconds; }; The nfstime4 structure gives the number of seconds and nanoseconds since midnight or 0 hour January 1, 1970 Coordinated Universal Time (UTC). Values greater than zero for the seconds field denote dates @@ -837,21 +913,21 @@ uint64_t major; uint64_t minor; }; This type is the filesystem identifier that is used as a mandatory attribute. 2.2.6. fs_location4 struct fs_location4 { - utf8str_cis server<>; + utf8val_must server<>; pathname4 rootpath; }; 2.2.7. fs_locations4 struct fs_locations4 { pathname4 fs_root; fs_location4 locations<>; }; @@ -895,22 +971,22 @@ struct clientaddr4 { /* see struct rpcb in RFC 1833 */ string r_netid<>; /* network id */ string r_addr<>; /* universal address */ }; The clientaddr4 structure is used as part of the SETCLIENTID operation to either specify the address of the client that is using a clientid or as part of the callback registration. The r_netid and - r_addr fields are specified in [16], but they are underspecified in - [16] as far as what they should look like for specific protocols. + r_addr fields are specified in [17], but they are underspecified in + [17] as far as what they should look like for specific protocols. For TCP over IPv4 and for UDP over IPv4, the format of r_addr is the US-ASCII string: h1.h2.h3.h4.p1.p2 The prefix, "h1.h2.h3.h4", is the standard textual form for representing an IPv4 address, which is always four octets long. Assuming big-endian ordering, h1, h2, h3, and h4, are respectively, the first through fourth octets each converted to ASCII-decimal. @@ -924,23 +1000,23 @@ over IPv4 the value of r_netid is the string "udp". For TCP over IPv6 and for UDP over IPv6, the format of r_addr is the US-ASCII string: x1:x2:x3:x4:x5:x6:x7:x8.p1.p2 The suffix "p1.p2" is the service port, and is computed the same way as with universal addresses for TCP and UDP over IPv4. The prefix, "x1:x2:x3:x4:x5:x6:x7:x8", is the standard textual form for - representing an IPv6 address as defined in Section 2.2 of [17]. + representing an IPv6 address as defined in Section 2.2 of [18]. Additionally, the two alternative forms specified in Section 2.2 of - [17] are also acceptable. + [18] are also acceptable. For TCP over IPv6 the value of r_netid is the string "tcp6". For UDP over IPv6 the value of r_netid is the string "udp6". 2.2.11. cb_client4 struct cb_client4 { unsigned int cb_program; clientaddr4 cb_location; }; @@ -1006,68 +1082,68 @@ is read-only. The starting value of the seqid field is undefined. The server is required to increment the seqid field monotonically at each transition of the stateid. This is important since the client will inspect the seqid in OPEN stateids to determine the order of OPEN processing done by the server. 3. RPC and Security Flavor The NFS version 4 protocol is a Remote Procedure Call (RPC) application that uses RPC version 2 and the corresponding eXternal - Data Representation (XDR) as defined in [3] and [14]. The RPCSEC_GSS + Data Representation (XDR) as defined in [3] and [15]. The RPCSEC_GSS security flavor as defined in [4] MUST be used as the mechanism to deliver stronger security for the NFS version 4 protocol. 3.1. Ports and Transports Historically, NFS version 2 and version 3 servers have resided on - port 2049. The registered port 2049 [18] for the NFS protocol should + port 2049. The registered port 2049 [19] for the NFS protocol should be the default configuration. Using the registered port for NFS services means the NFS client will not need to use the RPC binding - protocols as described in [16]; this will allow NFS to transit + protocols as described in [17]; this will allow NFS to transit firewalls. Where an NFS version 4 implementation supports operation over the IP network protocol, the supported transports between NFS and IP MUST be among the IETF-approved congestion control transport protocols, which include TCP and SCTP. To enhance the possibilities for interoperability, an NFS version 4 implementation MUST support operation over the TCP transport protocol, at least until such time as a standards track RFC revises this requirement to use a different IETF-approved congestion control transport protocol. If TCP is used as the transport, the client and server SHOULD use persistent connections. This will prevent the weakening of TCP's congestion control via short lived connections and will improve performance for the WAN environment by eliminating the need for SYN handshakes. - As noted in the Security Considerations section, the authentication - model for NFS version 4 has moved from machine-based to principal- - based. However, this modification of the authentication model does - not imply a technical requirement to move the TCP connection - management model from whole machine-based to one based on a per user - model. In particular, NFS over TCP client implementations have - traditionally multiplexed traffic for multiple users over a common - TCP connection between an NFS client and server. This has been true, - regardless whether the NFS client is using AUTH_SYS, AUTH_DH, - RPCSEC_GSS or any other flavor. Similarly, NFS over TCP server - implementations have assumed such a model and thus scale the - implementation of TCP connection management in proportion to the - number of expected client machines. It is intended that NFS version - 4 will not modify this connection management model. NFS version 4 - clients that violate this assumption can expect scaling issues on the - server and hence reduced service. + As noted in Section 17, the authentication model for NFS version 4 + has moved from machine-based to principal- based. However, this + modification of the authentication model does not imply a technical + requirement to move the TCP connection management model from whole + machine-based to one based on a per user model. In particular, NFS + over TCP client implementations have traditionally multiplexed + traffic for multiple users over a common TCP connection between an + NFS client and server. This has been true, regardless whether the + NFS client is using AUTH_SYS, AUTH_DH, RPCSEC_GSS or any other + flavor. Similarly, NFS over TCP server implementations have assumed + such a model and thus scale the implementation of TCP connection + management in proportion to the number of expected client machines. + + It is intended that NFS version 4 will not modify this connection + management model. NFS version 4 clients that violate this assumption + can expect scaling issues on the server and hence reduced service. Note that for various timers, the client and server should avoid inadvertent synchronization of those timers. For further discussion - of the general issue refer to [19]. + of the general issue refer to [20]. 3.1.1. Client Retransmission Behavior When processing a request received over a reliable transport such as TCP, the NFS version 4 server MUST NOT silently drop the request, except if the transport connection has been broken. Given such a contract between NFS version 4 clients and servers, clients MUST NOT retry a request unless one or both of the following are true: o The transport connection has been broken @@ -1108,21 +1184,21 @@ 3.2.1. Security mechanisms for NFS version 4 The use of RPCSEC_GSS requires selection of: mechanism, quality of protection, and service (authentication, integrity, privacy). The remainder of this document will refer to these three parameters of the RPCSEC_GSS security as the security triple. 3.2.1.1. Kerberos V5 as a security triple - The Kerberos V5 GSS-API mechanism as described in [15] MUST be + The Kerberos V5 GSS-API mechanism as described in [16] MUST be implemented and provide the following security triples. column descriptions: 1 == number of pseudo flavor 2 == name of pseudo flavor 3 == mechanism's OID 4 == mechanism's algorithm(s) 5 == RPCSEC_GSS service @@ -1136,82 +1212,80 @@ for privacy. Note that the pseudo flavor is presented here as a mapping aid to the implementor. Because this NFS protocol includes a method to negotiate security and it understands the GSS-API mechanism, the pseudo flavor is not needed. The pseudo flavor is needed for NFS version 3 since the security negotiation is done via the MOUNT protocol. For a discussion of NFS' use of RPCSEC_GSS and Kerberos V5, please - see [20]. + see [21]. Users and implementors are warned that 56 bit DES is no longer considered state of the art in terms of resistance to brute force - attacks. Once a revision to [15] is available that adds support for + attacks. Once a revision to [16] is available that adds support for AES, implementors are urged to incorporate AES into their NFSv4 over Kerberos V5 protocol stacks, and users are similarly urged to migrate to the use of AES. 3.2.1.2. LIPKEY as a security triple The LIPKEY GSS-API mechanism as described in [5] MAY be implemented and provide the following security triples. The definition of the - columns matches the previous subsection "Kerberos V5 as security - triple". + columns matches those in Section 3.2.1.1. 1 2 3 4 5 -------------------------------------------------------------------- 390006 lipkey 1.3.6.1.5.5.9 negotiated rpc_gss_svc_none 390007 lipkey-i 1.3.6.1.5.5.9 negotiated rpc_gss_svc_integrity 390008 lipkey-p 1.3.6.1.5.5.9 negotiated rpc_gss_svc_privacy The mechanism algorithm is listed as "negotiated". This is because LIPKEY is layered on SPKM-3 and in SPKM-3 [5] the confidentiality and integrity algorithms are negotiated. Since SPKM-3 specifies HMAC-MD5 for integrity as MANDATORY, 128 bit cast5CBC for confidentiality for privacy as MANDATORY, and further specifies that HMAC-MD5 and cast5CBC MUST be listed first before weaker algorithms, specifying "negotiated" in column 4 does not impair interoperability. In the event an SPKM-3 peer does not support the mandatory algorithms, the other peer is free to accept or reject the GSS-API context creation. Because SPKM-3 negotiates the algorithms, subsequent calls to LIPKEY's GSS_Wrap() and GSS_GetMIC() by RPCSEC_GSS will use a quality - of protection value of 0 (zero). See section 5.2 of [21] for an + of protection value of 0 (zero). See section 5.2 of [22] for an explanation. LIPKEY uses SPKM-3 to create a secure channel in which to pass a user name and password from the client to the server. Once the user name and password have been accepted by the server, calls to the LIPKEY context are redirected to the SPKM-3 context. See [5] for more details. 3.2.1.3. SPKM-3 as a security triple The SPKM-3 GSS-API mechanism as described in [5] MAY be implemented and provide the following security triples. The definition of the - columns matches the previous subsection "Kerberos V5 as security - triple". + columns matches those in Section 3.2.1.1. 1 2 3 4 5 -------------------------------------------------------------------- 390009 spkm3 1.3.6.1.5.5.1.3 negotiated rpc_gss_svc_none 390010 spkm3i 1.3.6.1.5.5.1.3 negotiated rpc_gss_svc_integrity 390011 spkm3p 1.3.6.1.5.5.1.3 negotiated rpc_gss_svc_privacy For a discussion as to why the mechanism algorithm is listed as - "negotiated", see Section 3.2.1.2 "LIPKEY as a security triple." + "negotiated", see Section 3.2.1.2. Because SPKM-3 negotiates the algorithms, subsequent calls to SPKM- 3's GSS_Wrap() and GSS_GetMIC() by RPCSEC_GSS will use a quality of - protection value of 0 (zero). See section 5.2 of [21] for an + protection value of 0 (zero). See section 5.2 of [22] for an explanation. Even though LIPKEY is layered over SPKM-3, SPKM-3 is specified as a mandatory set of triples to handle the situations where the initiator (the client) is anonymous or where the initiator has its own certificate. If the initiator is anonymous, there will not be a user name and password to send to the target (the server). If the initiator has its own certificate, then using passwords is superfluous. @@ -1222,21 +1296,21 @@ mechanism is to be used for its communication with the server. The NFS server may have multiple points within its filesystem name space that are available for use by NFS clients. In turn the NFS server may be configured such that each of these entry points may have different or multiple security mechanisms in use. The security negotiation between client and server must be done with a secure channel to eliminate the possibility of a third party intercepting the negotiation sequence and forcing the client and server to choose a lower level of security than required or desired. - See Section 16 "Security Considerations" for further discussion. + See Section 17 for further discussion. 3.3.1. SECINFO The new SECINFO operation will allow the client to determine, on a per filehandle basis, what security triple is to be used for server access. In general, the client will not have to use the SECINFO operation except during initial communication with the server or when the client crosses policy boundaries at the server. It is possible that the server's policies change during the client's interaction therefore forcing the client to negotiate a new security triple. @@ -1246,23 +1320,23 @@ Based on the assumption that each NFS version 4 client and server must support a minimum set of security (i.e., LIPKEY, SPKM-3, and Kerberos-V5 all under RPCSEC_GSS), the NFS client will start its communication with the server with one of the minimal security triples. During communication with the server, the client may receive an NFS error of NFS4ERR_WRONGSEC. This error allows the server to notify the client that the security triple currently being used is not appropriate for access to the server's filesystem resources. The client is then responsible for determining what security triples are available at the server and choose one which is - appropriate for the client. See Section 14.33 for the "SECINFO" - operation for further discussion of how the client will respond to - the NFS4ERR_WRONGSEC error and use SECINFO. + appropriate for the client. See Section 15.33 for further discussion + of how the client will respond to the NFS4ERR_WRONGSEC error and use + SECINFO. 3.3.3. Callback RPC Authentication Except as noted elsewhere in this section, the callback RPC (described later) MUST mutually authenticate the NFS server to the principal that acquired the clientid (also described later), using the security flavor the original SETCLIENTID operation used. For AUTH_NONE, there are no principals, so this is a non-issue. @@ -1348,50 +1422,50 @@ for a filesystem object. The contents of the filehandle are opaque to the client. Therefore, the server is responsible for translating the filehandle to an internal representation of the filesystem object. 4.1. Obtaining the First Filehandle The operations of the NFS protocol are defined in terms of one or more filehandles. Therefore, the client needs a filehandle to initiate communication with the server. With the NFS version 2 - protocol [12] and the NFS version 3 protocol [13], there exists an + protocol [13] and the NFS version 3 protocol [14], there exists an ancillary protocol to obtain this first filehandle. The MOUNT protocol, RPC program number 100005, provides the mechanism of translating a string based filesystem path name to a filehandle which can then be used by the NFS protocols. The MOUNT protocol has deficiencies in the area of security and use via firewalls. This is one reason that the use of the public - filehandle was introduced in [22] and [23]. With the use of the + filehandle was introduced in [23] and [24]. With the use of the public filehandle in combination with the LOOKUP operation in the NFS version 2 and 3 protocols, it has been demonstrated that the MOUNT protocol is unnecessary for viable interaction between NFS client and server. Therefore, the NFS version 4 protocol will not use an ancillary protocol for translation from string based path names to a filehandle. Two special filehandles will be used as starting points for the NFS client. 4.1.1. Root Filehandle The first of the special filehandles is the ROOT filehandle. The ROOT filehandle is the "conceptual" root of the filesystem name space at the NFS server. The client uses or starts with the ROOT filehandle by employing the PUTROOTFH operation. The PUTROOTFH operation instructs the server to set the "current" filehandle to the ROOT of the server's file tree. Once this PUTROOTFH operation is used, the client can then traverse the entirety of the server's file tree with the LOOKUP operation. A complete discussion of the server - name space is in the section "NFS Server Name Space". + name space is in Section 8. 4.1.2. Public Filehandle The second special filehandle is the PUBLIC filehandle. Unlike the ROOT filehandle, the PUBLIC filehandle may be bound or represent an arbitrary filesystem object at the server. The server is responsible for this binding. It may be that the PUBLIC filehandle and the ROOT filehandle refer to the same filesystem object. However, it is up to the administrative software at the server and the policies of the server administrator to define the binding of the PUBLIC filehandle @@ -1434,22 +1508,22 @@ doing a byte-by-byte comparison. However, the client MUST NOT otherwise interpret the contents of filehandles. If two filehandles from the same server are equal, they MUST refer to the same file. Servers SHOULD try to maintain a one-to-one correspondence between filehandles and files but this is not required. Clients MUST use filehandle comparisons only to improve performance, not for correct behavior. All clients need to be prepared for situations in which it cannot be determined whether two filehandles denote the same object and in such cases, avoid making invalid assumptions which might cause incorrect behavior. Further discussion of filehandle and attribute - comparison in the context of data caching is presented in the section - "Data Caching and File Identity". + comparison in the context of data caching is presented in + Section 10.3.4. As an example, in the case that two different path names when traversed at the server terminate at the same filesystem object, the server SHOULD return the same filehandle for each path. This can occur if a hard link is used to create two file names which refer to the same underlying file object and associated data. For example, if paths /a/b/c and /a/d/c refer to the same file, the server SHOULD return the same filehandle for both path names traversals. 4.2.2. Persistent Filehandle @@ -1590,851 +1663,1015 @@ GETFH Note that the COMPOUND procedure does not provide atomicity. This example only reduces the overhead of recovering from an expired filehandle. 5. File Attributes To meet the requirements of extensibility and increased interoperability with non-UNIX platforms, attributes must be handled - in a flexible manner. The NFS version 3 fattr3 structure contains a - fixed list of attributes that not all clients and servers are able to + in a flexible manner. The NFSv3 fattr3 structure contains a fixed + list of attributes that not all clients and servers are able to support or care about. The fattr3 structure can not be extended as new needs arise and it provides no way to indicate non-support. With - the NFS version 4 protocol, the client is able query what attributes - the server supports and construct requests with only those supported + the NFSv4.0 protocol, the client is able query what attributes the + server supports and construct requests with only those supported attributes (or a subset thereof). - To this end, attributes are divided into three groups: mandatory, - recommended, and named. Both mandatory and recommended attributes - are supported in the NFS version 4 protocol by a specific and well- - defined encoding and are identified by number. They are requested by - setting a bit in the bit vector sent in the GETATTR request; the - server response includes a bit vector to list what attributes were - returned in the response. New mandatory or recommended attributes - may be added to the NFS protocol between major revisions by - publishing a standards-track RFC which allocates a new attribute - number value and defines the encoding for the attribute. See - Section 10 "Minor Versioning" for further discussion. + To this end, attributes are divided into three groups: REQUIRED, + RECOMMENDED, and named. Both REQUIRED and RECOMMENDED attributes are + supported in the NFSv4.0 protocol by a specific and well-defined + encoding and are identified by number. They are requested by setting + a bit in the bit vector sent in the GETATTR request; the server + response includes a bit vector to list what attributes were returned + in the response. New REQUIRED or RECOMMENDED attributes may be added + to the NFSv4 protocol as part of a new minor version by publishing a + standards-track RFC which allocates a new attribute number value and + defines the encoding for the attribute. See Section 11 for further + discussion. Named attributes are accessed by the new OPENATTR operation, which accesses a hidden directory of attributes associated with a file system object. OPENATTR takes a filehandle for the object and returns the filehandle for the attribute hierarchy. The filehandle for the named attributes is a directory object accessible by LOOKUP or READDIR and contains files whose names represent the named attributes and whose data bytes are the value of the attribute. For example: - LOOKUP "foo" ; look up file - GETATTR attrbits - OPENATTR ; access foo's named attributes - LOOKUP "x11icon" ; look up specific attribute - READ 0,4096 ; read stream of bytes + +----------+-----------+---------------------------------+ + | LOOKUP | "foo" | ; look up file | + | GETATTR | attrbits | | + | OPENATTR | | ; access foo's named attributes | + | LOOKUP | "x11icon" | ; look up specific attribute | + | READ | 0,4096 | ; read stream of bytes | + +----------+-----------+---------------------------------+ Named attributes are intended for data needed by applications rather than by an NFS client implementation. NFS implementors are strongly - encouraged to define their new attributes as recommended attributes + encouraged to define their new attributes as RECOMMENDED attributes by bringing them to the IETF standards-track process. - The set of attributes which are classified as mandatory is + The set of attributes which are classified as REQUIRED is deliberately small since servers must do whatever it takes to support - them. A server should support as many of the recommended attributes + them. A server should support as many of the RECOMMENDED attributes as possible but by their definition, the server is not required to - support all of them. Attributes are deemed mandatory if the data is + support all of them. Attributes are deemed REQUIRED if the data is both needed by a large number of clients and is not otherwise reasonably computable by the client when support is not provided on the server. Note that the hidden directory returned by OPENATTR is a convenience for protocol processing. The client should not make any assumptions about the server's implementation of named attributes and whether the underlying filesystem at the server has a named attribute directory or not. Therefore, operations such as SETATTR and GETATTR on the named attribute directory are undefined. -5.1. Mandatory Attributes +5.1. REQUIRED Attributes - These MUST be supported by every NFS version 4 client and server in - order to ensure a minimum level of interoperability. The server must - store and return these attributes and the client must be able to - function with an attribute set limited to these attributes. With - just the mandatory attributes some client functionality may be - impaired or limited in some ways. A client may ask for any of these - attributes to be returned by setting a bit in the GETATTR request and - the server must return their value. + These MUST be supported by every NFSv4.0 client and server in order + to ensure a minimum level of interoperability. The server MUST store + and return these attributes and the client MUST be able to function + with an attribute set limited to these attributes. With just the + REQUIRED attributes some client functionality may be impaired or + limited in some ways. A client may ask for any of these attributes + to be returned by setting a bit in the GETATTR request and the server + must return their value. -5.2. Recommended Attributes +5.2. RECOMMENDED Attributes These attributes are understood well enough to warrant support in the - NFS version 4 protocol. However, they may not be supported on all - clients and servers. A client may ask for any of these attributes to - be returned by setting a bit in the GETATTR request but must handle - the case where the server does not return them. A client may ask for - the set of attributes the server supports and should not request + NFSv4.0 protocol. However, they may not be supported on all clients + and servers. A client may ask for any of these attributes to be + returned by setting a bit in the GETATTR request but must handle the + case where the server does not return them. A client may ask for the + set of attributes the server supports and SHOULD NOT request attributes the server does not support. A server should be tolerant of requests for unsupported attributes and simply not return them rather than considering the request an error. It is expected that servers will support all attributes they comfortably can and only fail to support attributes which are difficult to support in their operating environments. A server should provide attributes whenever they don't have to "tell lies" to the client. For example, a file modification time should be either an accurate time or should not be supported by the server. This will not always be comfortable to clients but the client is better positioned decide whether and how to fabricate or construct an attribute or whether to do without the attribute. 5.3. Named Attributes - These attributes are not supported by direct encoding in the NFS - Version 4 protocol but are accessed by string names rather than - numbers and correspond to an uninterpreted stream of bytes which are - stored with the filesystem object. The name space for these - attributes may be accessed by using the OPENATTR operation. The - OPENATTR operation returns a filehandle for a virtual "attribute - directory" and further perusal of the name space may be done using - READDIR and LOOKUP operations on this filehandle. Named attributes - may then be examined or changed by normal READ and WRITE and CREATE - operations on the filehandles returned from READDIR and LOOKUP. - Named attributes may have attributes. + These attributes are not supported by direct encoding in the NFSv4 + protocol but are accessed by string names rather than numbers and + correspond to an uninterpreted stream of bytes which are stored with + the file system object. The name space for these attributes may be + accessed by using the OPENATTR operation. The OPENATTR operation + returns a filehandle for a virtual "named attribute directory" and + further perusal and modification of the name space may be done using + operations that work on more typical directories. In particular, + READDIR may be used to get a list of such named attributes and LOOKUP + and OPEN may select a particular attribute. Creation of a new named + attribute may be the result of an OPEN specifying file creation. - It is recommended that servers support arbitrary named attributes. A + Once an OPEN is done, named attributes may be examined and changed by + normal READ and WRITE operations using the filehandles and stateids + returned by OPEN. + + Named attributes and the named attribute directory may have their own + (non-named) attributes. Each of objects must have all of the + REQUIRED attributes and may have additional RECOMMENDED attributes. + However, the set of attributes for named attributes and the named + attribute directory need not be as large as, and typically will not + be as large as that for other objects in that file system. + + Named attributes and the named attribute directory may be the target + of delegations (in the case of the named attribute directory these + will be directory delegations). However, since granting of + delegations or not is within the server's discretion, a server need + not support delegations on named attributes or the named attribute + directory. + + It is RECOMMENDED that servers support arbitrary named attributes. A client should not depend on the ability to store any named attributes in the server's filesystem. If a server does support named attributes, a client which is also able to handle them should be able - to copy a file's data and meta-data with complete transparency from + to copy a file's data and metadata with complete transparency from one location to another; this would imply that names allowed for regular directory entries are valid for named attribute names as well. + In NFSv4.0, the structure of named attribute directories is + restricted in a number of ways, in order to prevent the development + of non-interoperable implementations in which some servers support a + fully general hierarchical directory structure for named attributes + while others support a limited set, but fully adequate to the + feature's goals. In such an environment, clients or applications + might come to depend on non-portable extensions. The restrictions + are: + + o CREATE is not allowed in a named attribute directory. Thus, such + objects as symbolic links and special files are not allowed to be + named attributes. Further, directories may not be created in a + named attribute directory so no hierarchical structure of named + attributes for a single object is allowed. + + o If OPENATTR is done on a named attribute directory or on a named + attribute, the server MUST return NFS4ERR_WRONG_TYPE. + + o Doing a RENAME of a named attribute to a different named attribute + directory or to an ordinary (i.e. non-named-attribute) directory + is not allowed. + + o Creating hard links between named attribute directories or between + named attribute directories and ordinary directories is not + allowed. + Names of attributes will not be controlled by this document or other - IETF standards track documents. See Section 17 "IANA Considerations" - for further discussion. + IETF standards track documents. See Section 18 for further + discussion. 5.4. Classification of Attributes - Each of the Mandatory and Recommended attributes can be classified in - one of three categories: per server, per filesystem, or per - filesystem object. Note that it is possible that some per filesystem + Each of the REQUIRED and RECOMMENDED attributes can be classified in + one of three categories: per server, per file system, or per file + system object. Note that it is possible that some per file system attributes may vary within the filesystem. See the "homogeneous" attribute for its definition. Note that the attributes time_access_set and time_modify_set are not listed in this section because they are write-only attributes corresponding to time_access and time_modify, and are used in a special instance of SETATTR. o The per server attribute is: lease_time o The per filesystem attributes are: - supp_attr, fh_expire_type, link_support, symlink_support, + supported_attrs, fh_expire_type, link_support, symlink_support, unique_handles, aclsupport, cansettime, case_insensitive, case_preserving, chown_restricted, files_avail, files_free, files_total, fs_locations, homogeneous, maxfilesize, maxname, - maxread, maxwrite, no_trunc, space_avail, space_free, space_total, - time_delta + maxread, maxwrite, no_trunc, space_avail, space_free, + space_total, time_delta, o The per filesystem object attributes are: type, change, size, named_attr, fsid, rdattr_error, filehandle, - ACL, archive, fileid, hidden, maxlink, mimetype, mode, numlinks, - owner, owner_group, rawdev, space_used, system, time_access, - time_backup, time_create, time_metadata, time_modify, - mounted_on_fileid + acl, archive, fileid, hidden, maxlink, mimetype, mode, + numlinks, owner, owner_group, rawdev, space_used, system, + time_access, time_backup, time_create, time_metadata, + time_modify, mounted_on_fileid For quota_avail_hard, quota_avail_soft, and quota_used see their definitions below for the appropriate classification. -5.5. Mandatory Attributes - Definitions +5.5. Set-Only and Get-Only Attributes - +-----------------+----+------------+--------+----------------------+ - | Name | Id | Data Type | Access | Description | - +-----------------+----+------------+--------+----------------------+ - | supp_attr | 0 | bitmap | READ | The bit vector which | - | | | | | would retrieve all | - | | | | | mandatory and | - | | | | | recommended | - | | | | | attributes that are | - | | | | | supported for this | - | | | | | object. The scope of | - | | | | | this attribute | - | | | | | applies to all | - | | | | | objects with a | - | | | | | matching fsid. | - | type | 1 | nfs4_ftype | READ | The type of the | - | | | | | object (file, | - | | | | | directory, symlink, | - | | | | | etc.) | - | fh_expire_type | 2 | uint32 | READ | Server uses this to | - | | | | | specify filehandle | - | | | | | expiration behavior | - | | | | | to the client. See | - | | | | | Section 4 | - | | | | | "Filehandles" for | - | | | | | additional | - | | | | | description. | - | change | 3 | uint64 | READ | A value created by | - | | | | | the server that the | - | | | | | client can use to | - | | | | | determine if file | - | | | | | data, directory | - | | | | | contents or | - | | | | | attributes of the | - | | | | | object have been | - | | | | | modified. The server | - | | | | | may return the | - | | | | | object's | - | | | | | time_metadata | - | | | | | attribute for this | - | | | | | attribute's value | - | | | | | but only if the | - | | | | | filesystem object | - | | | | | can not be updated | - | | | | | more frequently than | - | | | | | the resolution of | - | | | | | time_metadata. | - | size | 4 | uint64 | R/W | The size of the | - | | | | | object in bytes. | - | link_support | 5 | bool | READ | True, if the | - | | | | | object's filesystem | - | | | | | supports hard links. | - | symlink_support | 6 | bool | READ | True, if the | - | | | | | object's filesystem | - | | | | | supports symbolic | - | | | | | links. | - | named_attr | 7 | bool | READ | True, if this object | - | | | | | has named | - | | | | | attributes. In other | - | | | | | words, object has a | - | | | | | non-empty named | - | | | | | attribute directory. | - | fsid | 8 | fsid4 | READ | Unique filesystem | - | | | | | identifier for the | - | | | | | filesystem holding | - | | | | | this object. fsid | - | | | | | contains major and | - | | | | | minor components | - | | | | | each of which are | - | | | | | uint64. | - | unique_handles | 9 | bool | READ | True, if two | - | | | | | distinct filehandles | - | | | | | guaranteed to refer | - | | | | | to two different | - | | | | | filesystem objects. | - | lease_time | 10 | nfs_lease4 | READ | Duration of leases | - | | | | | at server in | - | | | | | seconds. | - | rdattr_error | 11 | enum | READ | Error returned from | - | | | | | getattr during | - | | | | | readdir. | - | filehandle | 19 | nfs_fh4 | READ | The filehandle of | - | | | | | this object | - | | | | | (primarily for | - | | | | | readdir requests). | - +-----------------+----+------------+--------+----------------------+ + Some REQUIRED and RECOMMENDED attributes are set-only, i.e. they can + be set via SETATTR but not retrieved via GETATTR. Similarly, some + REQUIRED and RECOMMENDED attributes are get-only, i.e. they can be + retrieved GETATTR but not set via SETATTR. If a client attempts to + set a get-only attribute or get a set-only attributes, the server + MUST return NFS4ERR_INVAL. + +5.6. REQUIRED Attributes - List and Definition References + + The list of REQUIRED attributes appears in Table 2. The meaning of + the columns of the table are: + + o Name: the name of attribute + + o Id: the number assigned to the attribute. In the event of + conflicts between the assigned number and [2], the latter is + authoritative. + + o Data Type: The XDR data type of the attribute. + + o Acc: Access allowed to the attribute. R means read-only (GETATTR + may retrieve, SETATTR may not set). W means write-only (SETATTR + may set, GETATTR may not retrieve). R W means read/write (GETATTR + may retrieve, SETATTR may set). + + o Defined in: the section of this specification that describes the + attribute. + + +-----------------+----+------------+-----+------------------+ + | Name | Id | Data Type | Acc | Defined in: | + +-----------------+----+------------+-----+------------------+ + | supported_attrs | 0 | bitmap4 | R | Section 5.8.1.1 | + | type | 1 | nfs_ftype4 | R | Section 5.8.1.2 | + | fh_expire_type | 2 | uint32_t | R | Section 5.8.1.3 | + | change | 3 | uint64_t | R | Section 5.8.1.4 | + | size | 4 | uint64_t | R W | Section 5.8.1.5 | + | link_support | 5 | bool | R | Section 5.8.1.6 | + | symlink_support | 6 | bool | R | Section 5.8.1.7 | + | named_attr | 7 | bool | R | Section 5.8.1.8 | + | fsid | 8 | fsid4 | R | Section 5.8.1.9 | + | unique_handles | 9 | bool | R | Section 5.8.1.10 | + | lease_time | 10 | nfs_lease4 | R | Section 5.8.1.11 | + | rdattr_error | 11 | enum | R | Section 5.8.1.12 | + | filehandle | 19 | nfs_fh4 | R | Section 5.8.1.13 | + +-----------------+----+------------+-----+------------------+ Table 2 -5.6. Recommended Attributes - Definitions +5.7. RECOMMENDED Attributes - List and Definition References - +-------------------+----+--------------+--------+------------------+ - | Name | Id | Data Type | Access | Description | - +-------------------+----+--------------+--------+------------------+ - | ACL | 12 | nfsace4<> | R/W | The access | - | | | | | control list for | - | | | | | the object. | - | aclsupport | 13 | uint32 | READ | Indicates what | - | | | | | types of ACLs | - | | | | | are supported on | - | | | | | the current | - | | | | | filesystem. | - | archive | 14 | bool | R/W | True, if this | - | | | | | file has been | - | | | | | archived since | - | | | | | the time of last | - | | | | | modification | - | | | | | (deprecated in | - | | | | | favor of | - | | | | | time_backup). | - | cansettime | 15 | bool | READ | True, if the | - | | | | | server is able | - | | | | | to change the | - | | | | | times for a | - | | | | | filesystem | - | | | | | object as | - | | | | | specified in a | - | | | | | SETATTR | - | | | | | operation. | - | case_insensitive | 16 | bool | READ | True, if | - | | | | | filename | - | | | | | comparisons on | - | | | | | this filesystem | - | | | | | are case | - | | | | | insensitive. | - | case_preserving | 17 | bool | READ | True, if | - | | | | | filename case on | - | | | | | this filesystem | - | | | | | are preserved. | - | chown_restricted | 18 | bool | READ | If TRUE, the | - | | | | | server will | - | | | | | reject any | - | | | | | request to | - | | | | | change either | - | | | | | the owner or the | - | | | | | group associated | - | | | | | with a file if | - | | | | | the caller is | - | | | | | not a privileged | - | | | | | user (for | - | | | | | example, "root" | - | | | | | in UNIX | - | | | | | operating | - | | | | | environments or | - | | | | | in Windows 2000 | - | | | | | the "Take | - | | | | | Ownership" | - | | | | | privilege). | - | fileid | 20 | uint64 | READ | A number | - | | | | | uniquely | - | | | | | identifying the | - | | | | | file within the | - | | | | | filesystem. | - | files_avail | 21 | uint64 | READ | File slots | - | | | | | available to | - | | | | | this user on the | - | | | | | filesystem | - | | | | | containing this | - | | | | | object - this | - | | | | | should be the | - | | | | | smallest | - | | | | | relevant limit. | - | files_free | 22 | uint64 | READ | Free file slots | - | | | | | on the | - | | | | | filesystem | - | | | | | containing this | - | | | | | object - this | - | | | | | should be the | - | | | | | smallest | - | | | | | relevant limit. | - | files_total | 23 | uint64 | READ | Total file slots | - | | | | | on the | - | | | | | filesystem | - | | | | | containing this | - | | | | | object. | - | fs_locations | 24 | fs_locations | READ | Locations where | - | | | | | this filesystem | - | | | | | may be found. If | - | | | | | the server | - | | | | | returns | - | | | | | NFS4ERR_MOVED as | - | | | | | an error, this | - | | | | | attribute MUST | - | | | | | be supported. | - | hidden | 25 | bool | R/W | True, if the | - | | | | | file is | - | | | | | considered | - | | | | | hidden with | - | | | | | respect to the | - | | | | | Windows API. | - | homogeneous | 26 | bool | READ | True, if this | - | | | | | object's | - | | | | | filesystem is | - | | | | | homogeneous, | - | | | | | i.e., are per | - | | | | | filesystem | - | | | | | attributes the | - | | | | | same for all | - | | | | | filesystem's | - | | | | | objects? | - | maxfilesize | 27 | uint64 | READ | Maximum | - | | | | | supported file | - | | | | | size for the | - | | | | | filesystem of | - | | | | | this object. | - | maxlink | 28 | uint32 | READ | Maximum number | - | | | | | of links for | - | | | | | this object. | - | maxname | 29 | uint32 | READ | Maximum filename | - | | | | | size supported | - | | | | | for this object. | - | maxread | 30 | uint64 | READ | Maximum read | - | | | | | size supported | - | | | | | for this object. | - | maxwrite | 31 | uint64 | READ | Maximum write | - | | | | | size supported | - | | | | | for this object. | - | | | | | This attribute | - | | | | | SHOULD be | - | | | | | supported if the | - | | | | | file is | - | | | | | writable. Lack | - | | | | | of this | - | | | | | attribute can | - | | | | | lead to the | - | | | | | client either | - | | | | | wasting | - | | | | | bandwidth or not | - | | | | | receiving the | - | | | | | best | - | | | | | performance. | - | mimetype | 32 | utf8<> | R/W | MIME body | - | | | | | type/subtype of | - | | | | | this object. | - | mode | 33 | mode4 | R/W | UNIX-style mode | - | | | | | and permission | - | | | | | bits for this | - | | | | | object. | - | no_trunc | 34 | bool | READ | True, if a name | - | | | | | longer than | - | | | | | name_max is | - | | | | | used, an error | - | | | | | be returned and | - | | | | | name is not | - | | | | | truncated. | - | numlinks | 35 | uint32 | READ | Number of hard | - | | | | | links to this | - | | | | | object. | - | owner | 36 | utf8<> | R/W | The string name | - | | | | | of the owner of | - | | | | | this object. | - | owner_group | 37 | utf8<> | R/W | The string name | - | | | | | of the group | - | | | | | ownership of | - | | | | | this object. | - | quota_avail_hard | 38 | uint64 | READ | For definition | - | | | | | see Section 5.10 | - | | | | | "Quota | - | | | | | Attributes" | - | | | | | below. | - | quota_avail_soft | 39 | uint64 | READ | For definition | - | | | | | see Section 5.10 | - | | | | | "Quota | - | | | | | Attributes" | - | | | | | below. | - | quota_used | 40 | uint64 | READ | For definition | - | | | | | see Section 5.10 | - | | | | | "Quota | - | | | | | Attributes" | - | | | | | below. | - | rawdev | 41 | specdata4 | READ | Raw device | - | | | | | identifier. UNIX | - | | | | | device | - | | | | | major/minor node | - | | | | | information. If | - | | | | | the value of | - | | | | | type is not | - | | | | | NF4BLK or | - | | | | | NF4CHR, the | - | | | | | value return | - | | | | | SHOULD NOT be | - | | | | | considered | - | | | | | useful. | - | space_avail | 42 | uint64 | READ | Disk space in | - | | | | | bytes available | - | | | | | to this user on | - | | | | | the filesystem | - | | | | | containing this | - | | | | | object - this | - | | | | | should be the | - | | | | | smallest | - | | | | | relevant limit. | - | space_free | 43 | uint64 | READ | Free disk space | - | | | | | in bytes on the | - | | | | | filesystem | - | | | | | containing this | - | | | | | object - this | - | | | | | should be the | - | | | | | smallest | - | | | | | relevant limit. | - | space_total | 44 | uint64 | READ | Total disk space | - | | | | | in bytes on the | - | | | | | filesystem | - | | | | | containing this | - | | | | | object. | - | space_used | 45 | uint64 | READ | Number of | - | | | | | filesystem bytes | - | | | | | allocated to | - | | | | | this object. | - | system | 46 | bool | R/W | True, if this | - | | | | | file is a | - | | | | | "system" file | - | | | | | with respect to | - | | | | | the Windows API. | - | time_access | 47 | nfstime4 | READ | The time of last | - | | | | | access to the | - | | | | | object by a read | - | | | | | that was | - | | | | | satisfied by the | - | | | | | server. | - | time_access_set | 48 | settime4 | WRITE | Set the time of | - | | | | | last access to | - | | | | | the object. | - | | | | | SETATTR use | - | | | | | only. | - | time_backup | 49 | nfstime4 | R/W | The time of last | - | | | | | backup of the | - | | | | | object. | - | time_create | 50 | nfstime4 | R/W | The time of | - | | | | | creation of the | - | | | | | object. This | - | | | | | attribute does | - | | | | | not have any | - | | | | | relation to the | - | | | | | traditional UNIX | - | | | | | file attribute | - | | | | | "ctime" or | - | | | | | "change time". | - | time_delta | 51 | nfstime4 | READ | Smallest useful | - | | | | | server time | - | | | | | granularity. | - | time_metadata | 52 | nfstime4 | READ | The time of last | - | | | | | meta-data | - | | | | | modification of | - | | | | | the object. | - | time_modify | 53 | nfstime4 | READ | The time of last | - | | | | | modification to | - | | | | | the object. | - | time_modify_set | 54 | settime4 | WRITE | Set the time of | - | | | | | last | - | | | | | modification to | - | | | | | the object. | - | | | | | SETATTR use | - | | | | | only. | - | mounted_on_fileid | 55 | uint64 | READ | Like fileid, but | - | | | | | if the target | - | | | | | filehandle is | - | | | | | the root of a | - | | | | | filesystem | - | | | | | return the | - | | | | | fileid of the | - | | | | | underlying | - | | | | | directory. | - +-------------------+----+--------------+--------+------------------+ + The RECOMMENDED attributes are defined in Table 3. The meanings of + the column headers are the same as Table 2; see Section 5.6 for the + meanings. + + +-------------------+----+--------------+-----+------------------+ + | Name | Id | Data Type | Acc | Defined in: | + +-------------------+----+--------------+-----+------------------+ + | acl | 12 | nfsace4<> | R W | Section 6.2.1 | + | aclsupport | 13 | uint32_t | R | Section 6.2.1.2 | + | archive | 14 | bool | R W | Section 5.8.2.1 | + | cansettime | 15 | bool | R | Section 5.8.2.2 | + | case_insensitive | 16 | bool | R | Section 5.8.2.3 | + | case_preserving | 17 | bool | R | Section 5.8.2.4 | + | chown_restricted | 18 | bool | R | Section 5.8.2.5 | + | fileid | 20 | uint64_t | R | Section 5.8.2.6 | + | files_avail | 21 | uint64_t | R | Section 5.8.2.7 | + | files_free | 22 | uint64_t | R | Section 5.8.2.8 | + | files_total | 23 | uint64_t | R | Section 5.8.2.9 | + | fs_locations | 24 | fs_locations | R | Section 5.8.2.10 | + | hidden | 25 | bool | R W | Section 5.8.2.11 | + | homogeneous | 26 | bool | R | Section 5.8.2.12 | + | maxfilesize | 27 | uint64_t | R | Section 5.8.2.13 | + | maxlink | 28 | uint32_t | R | Section 5.8.2.14 | + | maxname | 29 | uint32_t | R | Section 5.8.2.15 | + | maxread | 30 | uint64_t | R | Section 5.8.2.16 | + | maxwrite | 31 | uint64_t | R | Section 5.8.2.17 | + | mimetype | 32 | utf8<> | R W | Section 5.8.2.18 | + | mode | 33 | mode4 | R W | Section 6.2.2 | + | mounted_on_fileid | 55 | uint64_t | R | Section 5.8.2.19 | + | no_trunc | 34 | bool | R | Section 5.8.2.20 | + | numlinks | 35 | uint32_t | R | Section 5.8.2.21 | + | owner | 36 | utf8<> | R W | Section 5.8.2.22 | + | owner_group | 37 | utf8<> | R W | Section 5.8.2.23 | + | quota_avail_hard | 38 | uint64_t | R | Section 5.8.2.24 | + | quota_avail_soft | 39 | uint64_t | R | Section 5.8.2.25 | + | quota_used | 40 | uint64_t | R | Section 5.8.2.26 | + | rawdev | 41 | specdata4 | R | Section 5.8.2.27 | + | space_avail | 42 | uint64_t | R | Section 5.8.2.28 | + | space_free | 43 | uint64_t | R | Section 5.8.2.29 | + | space_total | 44 | uint64_t | R | Section 5.8.2.30 | + | space_used | 45 | uint64_t | R | Section 5.8.2.31 | + | system | 46 | bool | R W | Section 5.8.2.32 | + | time_access | 47 | nfstime4 | R | Section 5.8.2.33 | + | time_access_set | 48 | settime4 | W | Section 5.8.2.34 | + | time_backup | 49 | nfstime4 | R W | Section 5.8.2.35 | + | time_create | 50 | nfstime4 | R W | Section 5.8.2.36 | + | time_delta | 51 | nfstime4 | R | Section 5.8.2.37 | + | time_metadata | 52 | nfstime4 | R | Section 5.8.2.38 | + | time_modify | 53 | nfstime4 | R | Section 5.8.2.39 | + | time_modify_set | 54 | settime4 | W | Section 5.8.2.40 | + +-------------------+----+--------------+-----+------------------+ Table 3 -5.7. Time Access +5.8. Attribute Definitions - As defined above, the time_access attribute represents the time of - last access to the object by a read that was satisfied by the server. - The notion of what is an "access" depends on server's operating - environment and/or the server's filesystem semantics. For example, - for servers obeying POSIX semantics, time_access would be updated - only by the READLINK, READ, and READDIR operations and not any of the - operations that modify the content of the object. Of course, setting - the corresponding time_access_set attribute is another way to modify - the time_access attribute. +5.8.1. Definitions of REQUIRED Attributes - Whenever the file object resides on a writable filesystem, the server - should make best efforts to record time_access into stable storage. - However, to mitigate the performance effects of doing so, and most - especially whenever the server is satisfying the read of the object's - content from its cache, the server MAY cache access time updates and - lazily write them to stable storage. It is also acceptable to give - administrators of the server the option to disable time_access - updates. +5.8.1.1. Attribute 0: supported_attrs -5.8. Interpreting owner and owner_group + The bit vector which would retrieve all REQUIRED and RECOMMENDED + attributes that are supported for this object. The scope of this + attribute applies to all objects with a matching fsid. - The recommended attributes "owner" and "owner_group" (and also users +5.8.1.2. Attribute 1: type + + Designates the type of an object in terms of one of a number of + special constants: + + o NF4REG designates a regular file. + + o NF4DIR designates a directory. + + o NF4BLK designates a block device special file. + + o NF4CHR designates a character device special file. + + o NF4LNK designates a symbolic link. + + o NF4SOCK designates a named socket special file. + + o NF4FIFO designates a fifo special file. + + o NF4ATTRDIR designates a named attribute directory. + + o NF4NAMEDATTR designates a named attribute. + + Within the explanatory text and operation descriptions, the following + phrases will be used with the meanings given below: + + o The phrase "is a directory" means that the object is of type + NF4DIR or of type NF4ATTRDIR. + + o The phrase "is a special file" means that the object is of one of + the types NF4BLK, NF4CHR, NF4SOCK, or NF4FIFO. + + o The phrase "is an ordinary file" means that the object is of type + NF4REG or of type NF4NAMEDATTR. + +5.8.1.3. Attribute 2: fh_expire_type + + Server uses this to specify filehandle expiration behavior to the + client. See Section 4 for additional description. + +5.8.1.4. Attribute 3: change + + A value created by the server that the client can use to determine if + file data, directory contents or attributes of the object have been + modified. The server may return the object's time_metadata attribute + for this attribute's value but only if the file system object can not + be updated more frequently than the resolution of time_metadata. + +5.8.1.5. Attribute 4: size + + The size of the object in bytes. + +5.8.1.6. Attribute 5: link_support + + True, if the object's file system supports hard links. + +5.8.1.7. Attribute 6: symlink_support + + True, if the object's file system supports symbolic links. + +5.8.1.8. Attribute 7: named_attr + + True, if this object has named attributes. In other words, object + has a non-empty named attribute directory. + +5.8.1.9. Attribute 8: fsid + + Unique file system identifier for the file system holding this + object. fsid contains major and minor components each of which are of + data type uint64_t. + +5.8.1.10. Attribute 9: unique_handles + + True, if two distinct filehandles guaranteed to refer to two + different file system objects. + +5.8.1.11. Attribute 10: lease_time + + Duration of leases at server in seconds. + +5.8.1.12. Attribute 11: rdattr_error + + Error returned from an attempt to retrieve attributes during a + READDIR operation. + +5.8.1.13. Attribute 19: filehandle + + The filehandle of this object (primarily for READDIR requests). + +5.8.2. Definitions of Uncategorized RECOMMENDED Attributes + + The definitions of most of the RECOMMENDED attributes follow. + Collections that share a common category are defined in other + sections. + +5.8.2.1. Attribute 14: archive + + True, if this file has been archived since the time of last + modification (deprecated in favor of time_backup). + +5.8.2.2. Attribute 15: cansettime + + True, if the server able to change the times for a file system object + as specified in a SETATTR operation. + +5.8.2.3. Attribute 16: case_insensitive + + True, if file name comparisons on this file system are case + insensitive. + +5.8.2.4. Attribute 17: case_preserving + + True, if file name case on this file system is preserved. + +5.8.2.5. Attribute 18: chown_restricted + + If TRUE, the server will reject any request to change either the + owner or the group associated with a file if the caller is not a + privileged user (for example, "root" in UNIX operating environments + or in Windows 2000 the "Take Ownership" privilege). + +5.8.2.6. Attribute 20: fileid + + A number uniquely identifying the file within the file system. + +5.8.2.7. Attribute 21: files_avail + + File slots available to this user on the file system containing this + object - this should be the smallest relevant limit. + +5.8.2.8. Attribute 22: files_free + + Free file slots on the file system containing this object - this + should be the smallest relevant limit. + +5.8.2.9. Attribute 23: files_total + + Total file slots on the file system containing this object. + +5.8.2.10. Attribute 24: fs_locations + + Locations where this file system may be found. If the server returns + NFS4ERR_MOVED as an error, this attribute MUST be supported. + +5.8.2.11. Attribute 25: hidden + + True, if the file is considered hidden with respect to the Windows + API. + +5.8.2.12. Attribute 26: homogeneous + + True, if this object's file system is homogeneous, i.e. are per file + system attributes the same for all file system's objects. + +5.8.2.13. Attribute 27: maxfilesize + + Maximum supported file size for the file system of this object. + +5.8.2.14. Attribute 28: maxlink + + Maximum number of links for this object. + +5.8.2.15. Attribute 29: maxname + + Maximum file name size supported for this object. + +5.8.2.16. Attribute 30: maxread + + Maximum read size supported for this object. + +5.8.2.17. Attribute 31: maxwrite + + Maximum write size supported for this object. This attribute SHOULD + be supported if the file is writable. Lack of this attribute can + lead to the client either wasting bandwidth or not receiving the best + performance. + +5.8.2.18. Attribute 32: mimetype + + MIME body type/subtype of this object. + +5.8.2.19. Attribute 55: mounted_on_fileid + + Like fileid, but if the target filehandle is the root of a file + system, this attribute represents the fileid of the underlying + directory. + + UNIX-based operating environments connect a file system into the + namespace by connecting (mounting) the file system onto the existing + file object (the mount point, usually a directory) of an existing + file system. When the mount point's parent directory is read via an + API like readdir(), the return results are directory entries, each + with a component name and a fileid. The fileid of the mount point's + directory entry will be different from the fileid that the stat() + system call returns. The stat() system call is returning the fileid + of the root of the mounted file system, whereas readdir() is + returning the fileid stat() would have returned before any file + systems were mounted on the mount point. + + Unlike NFSv3, NFSv4.0 allows a client's LOOKUP request to cross other + file systems. The client detects the file system crossing whenever + the filehandle argument of LOOKUP has an fsid attribute different + from that of the filehandle returned by LOOKUP. A UNIX-based client + will consider this a "mount point crossing". UNIX has a legacy + scheme for allowing a process to determine its current working + directory. This relies on readdir() of a mount point's parent and + stat() of the mount point returning fileids as previously described. + The mounted_on_fileid attribute corresponds to the fileid that + readdir() would have returned as described previously. + + While the NFSv4.0 client could simply fabricate a fileid + corresponding to what mounted_on_fileid provides (and if the server + does not support mounted_on_fileid, the client has no choice), there + is a risk that the client will generate a fileid that conflicts with + one that is already assigned to another object in the file system. + Instead, if the server can provide the mounted_on_fileid, the + potential for client operational problems in this area is eliminated. + + If the server detects that there is no mounted point at the target + file object, then the value for mounted_on_fileid that it returns is + the same as that of the fileid attribute. + + The mounted_on_fileid attribute is RECOMMENDED, so the server SHOULD + provide it if possible, and for a UNIX-based server, this is + straightforward. Usually, mounted_on_fileid will be requested during + a READDIR operation, in which case it is trivial (at least for UNIX- + based servers) to return mounted_on_fileid since it is equal to the + fileid of a directory entry returned by readdir(). If + mounted_on_fileid is requested in a GETATTR operation, the server + should obey an invariant that has it returning a value that is equal + to the file object's entry in the object's parent directory, i.e. + what readdir() would have returned. Some operating environments + allow a series of two or more file systems to be mounted onto a + single mount point. In this case, for the server to obey the + aforementioned invariant, it will need to find the base mount point, + and not the intermediate mount points. + +5.8.2.20. Attribute 34: no_trunc + + If this attribute is TRUE, then if the client uses a file name longer + than name_max, an error will be returned instead of the name being + truncated. + +5.8.2.21. Attribute 35: numlinks + + Number of hard links to this object. + +5.8.2.22. Attribute 36: owner + + The string name of the owner of this object. + +5.8.2.23. Attribute 37: owner_group + + The string name of the group ownership of this object. + +5.8.2.24. Attribute 38: quota_avail_hard + + The value in bytes which represents the amount of additional disk + space beyond the current allocation that can be allocated to this + file or directory before further allocations will be refused. It is + understood that this space may be consumed by allocations to other + files or directories. + +5.8.2.25. Attribute 39: quota_avail_soft + + The value in bytes which represents the amount of additional disk + space that can be allocated to this file or directory before the user + may reasonably be warned. It is understood that this space may be + consumed by allocations to other files or directories though there is + a rule as to which other files or directories. + +5.8.2.26. Attribute 40: quota_used + + The value in bytes which represent the amount of disc space used by + this file or directory and possibly a number of other similar files + or directories, where the set of "similar" meets at least the + criterion that allocating space to any file or directory in the set + will reduce the "quota_avail_hard" of every other file or directory + in the set. + + Note that there may be a number of distinct but overlapping sets of + files or directories for which a quota_used value is maintained. + E.g. "all files with a given owner", "all files with a given group + owner". etc. + + The server is at liberty to choose any of those sets but should do so + in a repeatable way. The rule may be configured per file system or + may be "choose the set with the smallest quota". + +5.8.2.27. Attribute 41: rawdev + + Raw device identifier; the UNIX device major/minor node information. + If the value of type is not NF4BLK or NF4CHR, the value returned + SHOULD NOT be considered useful. + +5.8.2.28. Attribute 42: space_avail + + Disk space in bytes available to this user on the file system + containing this object - this should be the smallest relevant limit. + +5.8.2.29. Attribute 43: space_free + + Free disk space in bytes on the file system containing this object - + this should be the smallest relevant limit. + +5.8.2.30. Attribute 44: space_total + + Total disk space in bytes on the file system containing this object. + +5.8.2.31. Attribute 45: space_used + + Number of file system bytes allocated to this object. + +5.8.2.32. Attribute 46: system + + This attribute is TRUE if this file is a "system" file with respect + to the Windows operating environment. + +5.8.2.33. Attribute 47: time_access + + The time_access attribute represents the time of last access to the + object by a read that was satisfied by the server. The notion of + what is an "access" depends on server's operating environment and/or + the server's file system semantics. For example, for servers obeying + POSIX semantics, time_access would be updated only by the READLINK, + READ, and READDIR operations and not any of the operations that + modify the content of the object. Of course, setting the + corresponding time_access_set attribute is another way to modify the + time_access attribute. + + Whenever the file object resides on a writable file system, the + server should make best efforts to record time_access into stable + storage. However, to mitigate the performance effects of doing so, + and most especially whenever the server is satisfying the read of the + object's content from its cache, the server MAY cache access time + updates and lazily write them to stable storage. It is also + acceptable to give administrators of the server the option to disable + time_access updates. + +5.8.2.34. Attribute 48: time_access_set + + Set the time of last access to the object. SETATTR use only. + +5.8.2.35. Attribute 49: time_backup + + The time of last backup of the object. + +5.8.2.36. Attribute 50: time_create + + The time of creation of the object. This attribute does not have any + relation to the traditional UNIX file attribute "ctime" or "change + time". + +5.8.2.37. Attribute 51: time_delta + + Smallest useful server time granularity. + +5.8.2.38. Attribute 52: time_metadata + + The time of last metadata modification of the object. + +5.8.2.39. Attribute 53: time_modify + + The time of last modification to the object. + +5.8.2.40. Attribute 54: time_modify_set + + Set the time of last modification to the object. SETATTR use only. + +5.9. Interpreting owner and owner_group + + The RECOMMENDED attributes "owner" and "owner_group" (and also users and groups within the "acl" attribute) are represented in terms of a UTF-8 string. To avoid a representation that is tied to a particular underlying implementation at the client or server, the use of the - UTF-8 string has been chosen. Note that section 6.1 of [24] provides - additional rationale. It is expected that the client and server will - have their own local representation of owner and owner_group that is - used for local storage or presentation to the end user. Therefore, - it is expected that when these attributes are transferred between the - client and server that the local representation is translated to a - syntax of the form "user@dns_domain". This will allow for a client - and server that do not use the same local representation the ability - to translate to a common syntax that can be interpreted by both. + UTF-8 string has been chosen. Note that section 6.1 of RFC2624 [25] + provides additional rationale. It is expected that the client and + server will have their own local representation of owner and + owner_group that is used for local storage or presentation to the end + user. Therefore, it is expected that when these attributes are + transferred between the client and server that the local + representation is translated to a syntax of the form "user@ + dns_domain". This will allow for a client and server that do not use + the same local representation the ability to translate to a common + syntax that can be interpreted by both. Similarly, security principals may be represented in different ways by different security mechanisms. Servers normally translate these representations into a common format, generally that used by local storage, to serve as a means of identifying the users corresponding to these security principals. When these local identifiers are translated to the form of the owner attribute, associated with files created by such principals they identify, in a common format, the users associated with each corresponding set of security principals. The translation used to interpret owner and group strings is not specified as part of the protocol. This allows various solutions to be employed. For example, a local translation table may be consulted - that maps between a numeric id to the user@dns_domain syntax. A name - service may also be used to accomplish the translation. A server may - provide a more general service, not limited by any particular - translation (which would only translate a limited set of possible - strings) by storing the owner and owner_group attributes in local - storage without any translation or it may augment a translation + that maps between a numeric identifier to the user@dns_domain syntax. + A name service may also be used to accomplish the translation. A + server may provide a more general service, not limited by any + particular translation (which would only translate a limited set of + possible strings) by storing the owner and owner_group attributes in + local storage without any translation or it may augment a translation method by storing the entire string for attributes for which no translation is available while using the local representation for those cases in which a translation is available. Servers that do not provide support for all possible values of the - owner and owner_group attributes, should return an error + owner and owner_group attributes, SHOULD return an error (NFS4ERR_BADOWNER) when a string is presented that has no translation, as the value to be set for a SETATTR of the owner, owner_group, or acl attributes. When a server does accept an owner or owner_group value as valid on a SETATTR (and similarly for the - owner and group strings in an acl), it is promising to return that - same string when a corresponding GETATTR is done. Configuration - changes and ill-constructed name translations (those that contain - aliasing) may make that promise impossible to honor. Servers should - make appropriate efforts to avoid a situation in which these - attributes have their values changed when no real change to ownership - has occurred. + owner and group strings in an acl), it needs to try to return that + same string for which see below) when a corresponding GETATTR is + done. For some internationalization-related exceptions where this is + not possible, see below. Configuration changes (including changes + from the mapping of the string to the local representation) and ill- + constructed name translations (those that contain aliasing) may make + that promise impossible to honor. Servers should make appropriate + efforts to avoid a situation in which these attributes have their + values changed when no real change to ownership has occurred. The "dns_domain" portion of the owner string is meant to be a DNS domain name. For example, user@ietf.org. Servers should accept as valid a set of users for at least one domain. A server may treat other domains as having no valid translations. A more general service is provided when a server is capable of accepting users for multiple domains, or for all domains, subject to security constraints. + As mentioned above, it is desirable that a server when accepting a + string of the form user@domain or group@domain in an attribute, + return this same string when that corresponding attribute is fetched. + Internationalization issues (for a general discussion of which see + Section 12) make this impossible and the client needs to take note of + the following situations: + + o The string representing the domain may be converted to equivalent + U-label, if presented using a form other a a U-label. See + Section 12.6 for details. + + o The user or group may be returned in a different form, due to + normalization issues, although it will always be a canonically + equivalent string. See See Section 12.7.3 for details. + In the case where there is no translation available to the client or server, the attribute value must be constructed without the "@". Therefore, the absence of the @ from the owner or owner_group attribute signifies that no translation was available at the sender and that the receiver of the attribute should not use that string as a basis for translation into its own internal format. Even though the attribute value can not be translated, it may still be useful. In the case of a client, the attribute string may be used for local display of ownership. - To provide a greater degree of compatibility with previous versions - of NFS (i.e., v2 and v3), which identified users and groups by 32-bit - unsigned uid's and gid's, owner and group strings that consist of - decimal numeric values with no leading zeros can be given a special + To provide a greater degree of compatibility with NFSv3, which + identified users and groups by 32-bit unsigned user identifiers and + group identifiers, owner and group strings that consist of decimal + numeric values with no leading zeros can be given a special interpretation by clients and servers which choose to provide such support. The receiver may treat such a user or group string as - representing the same user as would be represented by a v2/v3 uid or + representing the same user as would be represented by an NFSv3 uid or gid having the corresponding numeric value. A server is not obligated to accept such a string, but may return an NFS4ERR_BADOWNER instead. To avoid this mechanism being used to subvert user and group translation, so that a client might pass all of the owners and groups in numeric form, a server SHOULD return an NFS4ERR_BADOWNER error when there is a valid translation for the user or owner designated in this way. In that case, the client must use the appropriate name@domain string and not the special form for compatibility. The owner string "nobody" may be used to designate an anonymous user, which will be associated with a file created by a security principal that cannot be mapped through normal means to the owner attribute. -5.9. Character Case Attributes +5.10. Character Case Attributes With respect to the case_insensitive and case_preserving attributes, each UCS-4 character (which UTF-8 encodes) has a "long descriptive - name" [25] which may or may not included the word "CAPITAL" or + name" RFC1345 [26] which may or may not include the word "CAPITAL" or "SMALL". The presence of SMALL or CAPITAL allows an NFS server to implement unambiguous and efficient table driven mappings for case - insensitive comparisons, and non-case-preserving storage. For - general character handling and internationalization issues, see - Section 1 "Internationalization". + insensitive comparisons, and non-case-preserving storage, although + there are variations that occur additional characters with a name + including "SMALL" or "CAPITAL" are added in a subsequent version of + Unicode. -5.10. Quota Attributes + For general character handling and internationalization issues, see + Section 12. For details regarding case mapping, see the section + Case-based Mapping Used for Component4 Strings. - For the attributes related to filesystem quotas, the following - definitions apply: +6. Access Control Attributes - quota_avail_soft The value in bytes which represents the amount of - additional disk space that can be allocated to this file or - directory before the user may reasonably be warned. It is - understood that this space may be consumed by allocations to other - files or directories though there is a rule as to which other - files or directories. + Access Control Lists (ACLs) are file attributes that specify fine + grained access control. This chapter covers the "acl", "aclsupport", + "mode", file attributes, and their interactions. Note that file + attributes may apply to any file system object. - quota_avail_hard The value in bytes which represent the amount of - additional disk space beyond the current allocation that can be - allocated to this file or directory before further allocations - will be refused. It is understood that this space may be consumed - by allocations to other files or directories. +6.1. Goals - quota_used The value in bytes which represent the amount of disc - space used by this file or directory and possibly a number of - other similar files or directories, where the set of "similar" - meets at least the criterion that allocating space to any file or - directory in the set will reduce the "quota_avail_hard" of every - other file or directory in the set. + ACLs and modes represent two well established models for specifying + permissions. This chapter specifies requirements that attempt to + meet the following goals: - Note that there may be a number of distinct but overlapping sets - of files or directories for which a quota_used value is maintained - (e.g., "all files with a given owner", "all files with a given - group owner", etc.). + o If a server supports the mode attribute, it should provide + reasonable semantics to clients that only set and retrieve the + mode attribute. - The server is at liberty to choose any of those sets but should do - so in a repeatable way. The rule may be configured per-filesystem - or may be "choose the set with the smallest quota". + o If a server supports ACL attributes, it should provide reasonable + semantics to clients that only set and retrieve those attributes. -5.11. Access Control Lists + o On servers that support the mode attribute, if ACL attributes have + never been set on an object, via inheritance or explicitly, the + behavior should be traditional UNIX-like behavior. - The NFS version 4 ACL attribute is an array of access control entries - (ACE). Although, the client can read and write the ACL attribute, - the NFSv4 model is the server does all access control based on the - server's interpretation of the ACL. If at any point the client wants - to check access without issuing an operation that modifies or reads - data or metadata, the client can use the OPEN and ACCESS operations - to do so. There are various access control entry types, as defined - in the Section "ACE type". The server is able to communicate which - ACE types are supported by returning the appropriate value within the - aclsupport attribute. Each ACE covers one or more operations on a - file or directory as described in the Section "ACE Access Mask". It - may also contain one or more flags that modify the semantics of the - ACE as defined in the Section "ACE flag". + o On servers that support the mode attribute, if the ACL attributes + have been previously set on an object, either explicitly or via + inheritance: - The NFS ACE attribute is defined as follows: + * Setting only the mode attribute should effectively control the + traditional UNIX-like permissions of read, write, and execute + on owner, owner_group, and other. + + * Setting only the mode attribute should provide reasonable + security. For example, setting a mode of 000 should be enough + to ensure that future opens for read or write by any principal + fail, regardless of a previously existing or inherited ACL. + + o When a mode attribute is set on an object, the ACL attributes may + need to be modified so as to not conflict with the new mode. In + such cases, it is desirable that the ACL keep as much information + as possible. This includes information about inheritance, AUDIT + and ALARM ACEs, and permissions granted and denied that do not + conflict with the new mode. + +6.2. File Attributes Discussion + +6.2.1. Attribute 12: acl + + The NFSv4.0 ACL attribute contains an array of access control entries + (ACEs) that are associated with the file system object. Although the + client can read and write the acl attribute, the server is + responsible for using the ACL to perform access control. The client + can use the OPEN or ACCESS operations to check access without + modifying or reading data or metadata. + + The NFS ACE structure is defined as follows: typedef uint32_t acetype4; typedef uint32_t aceflag4; typedef uint32_t acemask4; struct nfsace4 { acetype4 type; aceflag4 flag; acemask4 access_mask; - utf8str_mixed who; + utf8_must who; }; - To determine if a request succeeds, each nfsace4 entry is processed - in order by the server. Only ACEs which have a "who" that matches - the requester are considered. Each ACE is processed until all of the + To determine if a request succeeds, the server processes each nfsace4 + entry in order. Only ACEs which have a "who" that matches the + requester are considered. Each ACE is processed until all of the bits of the requester's access have been ALLOWED. Once a bit (see below) has been ALLOWED by an ACCESS_ALLOWED_ACE, it is no longer considered in the processing of later ACEs. If an ACCESS_DENIED_ACE is encountered where the requester's access still has unALLOWED bits in common with the "access_mask" of the ACE, the request is denied. - However, unlike the ALLOWED and DENIED ACE types, the ALARM and AUDIT - ACE types do not affect a requester's access, and instead are for - triggering events as a result of a requester's access attempt. + When the ACL is fully processed, if there are bits in the requester's + mask that have not been ALLOWED or DENIED, access is denied. - Therefore, all AUDIT and ALARM ACEs are processed until end of the - ACL. When the ACL is fully processed, if there are bits in - requester's mask that have not been considered whether the server - allows or denies the access is undefined. If there is a mode - attribute on the file, then this cannot happen, since the mode's - MODE4_*OTH bits will map to EVERYONE@ ACEs that unambiguously specify - the requester's access. + Unlike the ALLOW and DENY ACE types, the ALARM and AUDIT ACE types do + not affect a requester's access, and instead are for triggering + events as a result of a requester's access attempt. Therefore, AUDIT + and ALARM ACEs are processed only after processing ALLOW and DENY + ACEs. - The NFS version 4 ACL model is quite rich. Some server platforms may + The NFSv4.0 ACL model is quite rich. Some server platforms may provide access control functionality that goes beyond the UNIX-style mode attribute, but which is not as rich as the NFS ACL model. So that users can take advantage of this more limited functionality, the - server may indicate that it supports ACLs as long as it follows the - guidelines for mapping between its ACL model and the NFS version 4 - ACL model. + server may support the acl attributes by mapping between its ACL + model and the NFSv4.0 ACL model. Servers must ensure that the ACL + they actually store or enforce is at least as strict as the NFSv4 ACL + that was set. It is tempting to accomplish this by rejecting any ACL + that falls outside the small set that can be represented accurately. + However, such an approach can render ACLs unusable without special + client-side knowledge of the server's mapping, which defeats the + purpose of having a common NFSv4 ACL protocol. Therefore servers + should accept every ACL that they can without compromising security. + To help accomplish this, servers may make a special exception, in the + case of unsupported permission bits, to the rule that bits not + ALLOWED or DENIED by an ACL must be denied. For example, a UNIX- + style server might choose to silently allow read attribute + permissions even though an ACL does not explicitly allow those + permissions. (An ACL that explicitly denies permission to read + attributes should still be rejected.) The situation is complicated by the fact that a server may have multiple modules that enforce ACLs. For example, the enforcement for - NFS version 4 access may be different from the enforcement for local - access, and both may be different from the enforcement for access - through other protocols such as SMB. So it may be useful for a - server to accept an ACL even if not all of its modules are able to - support it. + NFSv4.0 access may be different from, but not weaker than, the + enforcement for local access, and both may be different from the + enforcement for access through other protocols such as SMB. So it + may be useful for a server to accept an ACL even if not all of its + modules are able to support it. - The guiding principle in all cases is that the server must not accept - ACLs that appear to make the file more secure than it really is. + The guiding principle with regard to NFSv4 access is that the server + must not accept ACLs that appear to make access to the file more + restrictive than it really is. -5.11.1. ACE type +6.2.1.1. ACE Type - +-------+-----------------------------------------------------------+ - | Type | Description | - +-------+-----------------------------------------------------------+ - | ALLOW | Explicitly grants the access defined in acemask4 to the | - | | file or directory. | - | DENY | Explicitly denies the access defined in acemask4 to the | - | | file or directory. | - | AUDIT | LOG (system dependent) any access attempt to a file or | - | | directory which uses any of the access methods specified | - | | in acemask4. | - | ALARM | Generate a system ALARM (system dependent) when any | - | | access attempt is made to a file or directory for the | - | | access methods specified in acemask4. | - +-------+-----------------------------------------------------------+ + The constants used for the type field (acetype4) are as follows: - Table 4 + const ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000; + const ACE4_ACCESS_DENIED_ACE_TYPE = 0x00000001; + const ACE4_SYSTEM_AUDIT_ACE_TYPE = 0x00000002; + const ACE4_SYSTEM_ALARM_ACE_TYPE = 0x00000003; + All four but types are permitted in the acl attribute. - A server need not support all of the above ACE types. The bitmask - constants used to represent the above definitions within the - aclsupport attribute are as follows: + +------------------------------+--------------+---------------------+ + | Value | Abbreviation | Description | + +------------------------------+--------------+---------------------+ + | ACE4_ACCESS_ALLOWED_ACE_TYPE | ALLOW | Explicitly grants | + | | | the access defined | + | | | in acemask4 to the | + | | | file or directory. | + | ACE4_ACCESS_DENIED_ACE_TYPE | DENY | Explicitly denies | + | | | the access defined | + | | | in acemask4 to the | + | | | file or directory. | + | ACE4_SYSTEM_AUDIT_ACE_TYPE | AUDIT | LOG (in a system | + | | | dependent way) any | + | | | access attempt to a | + | | | file or directory | + | | | which uses any of | + | | | the access methods | + | | | specified in | + | | | acemask4. | + | ACE4_SYSTEM_ALARM_ACE_TYPE | ALARM | Generate a system | + | | | ALARM (system | + | | | dependent) when any | + | | | access attempt is | + | | | made to a file or | + | | | directory for the | + | | | access methods | + | | | specified in | + | | | acemask4. | + +------------------------------+--------------+---------------------+ + + The "Abbreviation" column denotes how the types will be referred to + throughout the rest of this chapter. + +6.2.1.2. Attribute 13: aclsupport + + A server need not support all of the above ACE types. This attribute + indicates which ACE types are supported for the current file system. + The bitmask constants used to represent the above definitions within + the aclsupport attribute are as follows: const ACL4_SUPPORT_ALLOW_ACL = 0x00000001; const ACL4_SUPPORT_DENY_ACL = 0x00000002; const ACL4_SUPPORT_AUDIT_ACL = 0x00000004; const ACL4_SUPPORT_ALARM_ACL = 0x00000008; - The semantics of the "type" field follow the descriptions provided - above. - - The constants used for the type field (acetype4) are as follows: - - const ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000; - const ACE4_ACCESS_DENIED_ACE_TYPE = 0x00000001; - const ACE4_SYSTEM_AUDIT_ACE_TYPE = 0x00000002; - const ACE4_SYSTEM_ALARM_ACE_TYPE = 0x00000003; + Servers which support either the ALLOW or DENY ACE type SHOULD + support both ALLOW and DENY ACE types. Clients should not attempt to set an ACE unless the server claims support for that ACE type. If the server receives a request to set an ACE that it cannot store, it MUST reject the request with NFS4ERR_ATTRNOTSUPP. If the server receives a request to set an ACE that it can store but cannot enforce, the server SHOULD reject the request with NFS4ERR_ATTRNOTSUPP. - Example: suppose a server can enforce NFS ACLs for NFS access but - cannot enforce ACLs for local access. If arbitrary processes can run - on the server, then the server SHOULD NOT indicate ACL support. On - the other hand, if only trusted administrative programs run locally, - then the server may indicate ACL support. - -5.11.2. ACE Access Mask - - The access_mask field contains values based on the following: - - +-------------------+-----------------------------------------------+ - | Access | Description | - +-------------------+-----------------------------------------------+ - | READ_DATA | Permission to read the data of the file | - | LIST_DIRECTORY | Permission to list the contents of a | - | | directory | - | WRITE_DATA | Permission to modify the file's data | - | ADD_FILE | Permission to add a new file to a directory | - | APPEND_DATA | Permission to append data to a file | - | ADD_SUBDIRECTORY | Permission to create a subdirectory to a | - | | directory | - | READ_NAMED_ATTRS | Permission to read the named attributes of a | - | | file | - | WRITE_NAMED_ATTRS | Permission to write the named attributes of a | - | | file | - | EXECUTE | Permission to execute a file | - | DELETE_CHILD | Permission to delete a file or directory | - | | within a directory | - | READ_ATTRIBUTES | The ability to read basic attributes | - | | (non-acls) of a file | - | WRITE_ATTRIBUTES | Permission to change basic attributes | - | | (non-acls) of a file | - | DELETE | Permission to Delete the file | - | READ_ACL | Permission to Read the ACL | - | WRITE_ACL | Permission to Write the ACL | - | WRITE_OWNER | Permission to change the owner | - | SYNCHRONIZE | Permission to access file locally at the | - | | server with synchronous reads and writes | - +-------------------+-----------------------------------------------+ + Support for any of the ACL attributes is optional (albeit, + RECOMMENDED). - Table 5 +6.2.1.3. ACE Access Mask The bitmask constants used for the access mask field are as follows: const ACE4_READ_DATA = 0x00000001; const ACE4_LIST_DIRECTORY = 0x00000001; const ACE4_WRITE_DATA = 0x00000002; const ACE4_ADD_FILE = 0x00000002; const ACE4_APPEND_DATA = 0x00000004; const ACE4_ADD_SUBDIRECTORY = 0x00000004; const ACE4_READ_NAMED_ATTRS = 0x00000008; @@ -2443,420 +2680,2020 @@ const ACE4_DELETE_CHILD = 0x00000040; const ACE4_READ_ATTRIBUTES = 0x00000080; const ACE4_WRITE_ATTRIBUTES = 0x00000100; const ACE4_DELETE = 0x00010000; const ACE4_READ_ACL = 0x00020000; const ACE4_WRITE_ACL = 0x00040000; const ACE4_WRITE_OWNER = 0x00080000; const ACE4_SYNCHRONIZE = 0x00100000; - Server implementations need not provide the granularity of control - that is implied by this list of masks. For example, POSIX-based - systems might not distinguish APPEND_DATA (the ability to append to a - file) from WRITE_DATA (the ability to modify existing contents); both - masks would be tied to a single "write" permission. When such a - server returns attributes to the client, it would show both - APPEND_DATA and WRITE_DATA if and only if the write permission is - enabled. + Note that some masks have coincident values, for example, + ACE4_READ_DATA and ACE4_LIST_DIRECTORY. The mask entries + ACE4_LIST_DIRECTORY, ACE4_ADD_FILE, and ACE4_ADD_SUBDIRECTORY are + intended to be used with directory objects, while ACE4_READ_DATA, + ACE4_WRITE_DATA, and ACE4_APPEND_DATA are intended to be used with + non-directory objects. - If a server receives a SETATTR request that it cannot accurately - implement, it should error in the direction of more restricted - access. For example, suppose a server cannot distinguish overwriting - data from appending new data, as described in the previous paragraph. - If a client submits an ACE where APPEND_DATA is set but WRITE_DATA is - not (or vice versa), the server should reject the request with - NFS4ERR_ATTRNOTSUPP. Nonetheless, if the ACE has type DENY, the - server may silently turn on the other bit, so that both APPEND_DATA - and WRITE_DATA are denied. +6.2.1.3.1. Discussion of Mask Attributes + ACE4_READ_DATA -5.11.3. ACE flag + Operation(s) affected: - The "flag" field contains values based on the following descriptions. + READ - ACE4_FILE_INHERIT_ACE Can be placed on a directory and indicates - that this ACE should be added to each new non-directory file - created. + OPEN - ACE4_DIRECTORY_INHERIT_ACE Can be placed on a directory and - indicates that this ACE should be added to each new directory - created. + Discussion: - ACE4_INHERIT_ONLY_ACE Can be placed on a directory but does not - apply to the directory, only to newly created files/directories as - specified by the above two flags. + Permission to read the data of the file. - ACE4_NO_PROPAGATE_INHERIT_ACE Can be placed on a directory. - Normally when a new directory is created and an ACE exists on the - parent directory which is marked ACL4_DIRECTORY_INHERIT_ACE, two - ACEs are placed on the new directory. One for the directory - itself and one which is an inheritable ACE for newly created - directories. This flag tells the server to not place an ACE on - the newly created directory which is inheritable by subdirectories - of the created directory. + Servers SHOULD allow a user the ability to read the data of the + file when only the ACE4_EXECUTE access mask bit is allowed. - ACE4_SUCCESSFUL_ACCESS_ACE_FLAG + ACE4_LIST_DIRECTORY - ACL4_FAILED_ACCESS_ACE_FLAG The ACE4_SUCCESSFUL_ACCESS_ACE_FLAG - (SUCCESS) and ACE4_FAILED_ACCESS_ACE_FLAG (FAILED) flag bits - relate only to ACE4_SYSTEM_AUDIT_ACE_TYPE (AUDIT) and - ACE4_SYSTEM_ALARM_ACE_TYPE (ALARM) ACE types. If during the - processing of the file's ACL, the server encounters an AUDIT or - ALARM ACE that matches the principal attempting the OPEN, the - server notes that fact, and the presence, if any, of the SUCCESS - and FAILED flags encountered in the AUDIT or ALARM ACE. Once the - server completes the ACL processing, and the share reservation - processing, and the OPEN call, it then notes if the OPEN succeeded - or failed. If the OPEN succeeded, and if the SUCCESS flag was set - for a matching AUDIT or ALARM, then the appropriate AUDIT or ALARM - event occurs. If the OPEN failed, and if the FAILED flag was set - for the matching AUDIT or ALARM, then the appropriate AUDIT or - ALARM event occurs. Clearly either or both of the SUCCESS or - FAILED can be set, but if neither is set, the AUDIT or ALARM ACE - is not useful. + Operation(s) affected: - The previously described processing applies to that of the ACCESS - operation as well. The difference being that "success" or - "failure" does not mean whether ACCESS returns NFS4_OK or not. - Success means whether ACCESS returns all requested and supported - bits. Failure means whether ACCESS failed to return a bit that - was requested and supported. + READDIR - ACE4_IDENTIFIER_GROUP Indicates that the "who" refers to a GROUP as - defined under UNIX. + Discussion: + + Permission to list the contents of a directory. + + ACE4_WRITE_DATA + + Operation(s) affected: + + WRITE + + OPEN + + SETATTR of size + + Discussion: + + Permission to modify a file's data. + + ACE4_ADD_FILE + + Operation(s) affected: + + CREATE + LINK + + OPEN + + RENAME + + Discussion: + + Permission to add a new file in a directory. The CREATE + operation is affected when nfs_ftype4 is NF4LNK, NF4BLK, + NF4CHR, NF4SOCK, or NF4FIFO. (NF4DIR is not listed because it + is covered by ACE4_ADD_SUBDIRECTORY.) OPEN is affected when + used to create a regular file. LINK and RENAME are always + affected. + + ACE4_APPEND_DATA + + Operation(s) affected: + + WRITE + + OPEN + + SETATTR of size + + Discussion: + + The ability to modify a file's data, but only starting at EOF. + This allows for the notion of append-only files, by allowing + ACE4_APPEND_DATA and denying ACE4_WRITE_DATA to the same user + or group. If a file has an ACL such as the one described above + and a WRITE request is made for somewhere other than EOF, the + server SHOULD return NFS4ERR_ACCESS. + + ACE4_ADD_SUBDIRECTORY + + Operation(s) affected: + + CREATE + + RENAME + + Discussion: + + Permission to create a subdirectory in a directory. The CREATE + operation is affected when nfs_ftype4 is NF4DIR. The RENAME + operation is always affected. + + ACE4_READ_NAMED_ATTRS + + Operation(s) affected: + + OPENATTR + + Discussion: + + Permission to read the named attributes of a file or to lookup + the named attributes directory. OPENATTR is affected when it + is not used to create a named attribute directory. This is + when 1.) createdir is TRUE, but a named attribute directory + already exists, or 2.) createdir is FALSE. + + ACE4_WRITE_NAMED_ATTRS + + Operation(s) affected: + + OPENATTR + + Discussion: + + Permission to write the named attributes of a file or to create + a named attribute directory. OPENATTR is affected when it is + used to create a named attribute directory. This is when + createdir is TRUE and no named attribute directory exists. The + ability to check whether or not a named attribute directory + exists depends on the ability to look it up, therefore, users + also need the ACE4_READ_NAMED_ATTRS permission in order to + create a named attribute directory. + + ACE4_EXECUTE + + Operation(s) affected: + + READ + + OPEN + + REMOVE + + RENAME + LINK + + CREATE + + Discussion: + + Permission to execute a file. + + Servers SHOULD allow a user the ability to read the data of the + file when only the ACE4_EXECUTE access mask bit is allowed. + This is because there is no way to execute a file without + reading the contents. Though a server may treat ACE4_EXECUTE + and ACE4_READ_DATA bits identically when deciding to permit a + READ operation, it SHOULD still allow the two bits to be set + independently in ACLs, and MUST distinguish between them when + replying to ACCESS operations. In particular, servers SHOULD + NOT silently turn on one of the two bits when the other is set, + as that would make it impossible for the client to correctly + enforce the distinction between read and execute permissions. + + As an example, following a SETATTR of the following ACL: + + nfsuser:ACE4_EXECUTE:ALLOW + + A subsequent GETATTR of ACL for that file SHOULD return: + + nfsuser:ACE4_EXECUTE:ALLOW + + Rather than: + + nfsuser:ACE4_EXECUTE/ACE4_READ_DATA:ALLOW + + ACE4_EXECUTE + + Operation(s) affected: + + LOOKUP + + Discussion: + + Permission to traverse/search a directory. + + ACE4_DELETE_CHILD + + Operation(s) affected: + + REMOVE + + RENAME + + Discussion: + + Permission to delete a file or directory within a directory. + See Section 6.2.1.3.2 for information on ACE4_DELETE and + ACE4_DELETE_CHILD interact. + + ACE4_READ_ATTRIBUTES + + Operation(s) affected: + + GETATTR of file system object attributes + + VERIFY + + NVERIFY + + READDIR + + Discussion: + + The ability to read basic attributes (non-ACLs) of a file. On + a UNIX system, basic attributes can be thought of as the stat + level attributes. Allowing this access mask bit would mean the + entity can execute "ls -l" and stat. If a READDIR operation + requests attributes, this mask must be allowed for the READDIR + to succeed. + + ACE4_WRITE_ATTRIBUTES + + Operation(s) affected: + + SETATTR of time_access_set, time_backup, + + time_create, time_modify_set, mimetype, hidden, system + + Discussion: + + Permission to change the times associated with a file or + directory to an arbitrary value. Also permission to change the + mimetype, hidden and system attributes. A user having + ACE4_WRITE_DATA or ACE4_WRITE_ATTRIBUTES will be allowed to set + the times associated with a file to the current server time. + + ACE4_DELETE + + Operation(s) affected: + + REMOVE + + Discussion: + + Permission to delete the file or directory. See + Section 6.2.1.3.2 for information on ACE4_DELETE and + ACE4_DELETE_CHILD interact. + + ACE4_READ_ACL + + Operation(s) affected: + + GETATTR of acl + + NVERIFY + + VERIFY + + Discussion: + + Permission to read the ACL. + + ACE4_WRITE_ACL + + Operation(s) affected: + + SETATTR of acl and mode + + Discussion: + + Permission to write the acl and mode attributes. + + ACE4_WRITE_OWNER + + Operation(s) affected: + + SETATTR of owner and owner_group + + Discussion: + + Permission to write the owner and owner_group attributes. On + UNIX systems, this is the ability to execute chown() and + chgrp(). + + ACE4_SYNCHRONIZE + + Operation(s) affected: + + NONE + + Discussion: + + Permission to access file locally at the server with + synchronized reads and writes. + + Server implementations need not provide the granularity of control + that is implied by this list of masks. For example, POSIX-based + systems might not distinguish ACE4_APPEND_DATA (the ability to append + to a file) from ACE4_WRITE_DATA (the ability to modify existing + contents); both masks would be tied to a single "write" permission. + When such a server returns attributes to the client, it would show + both ACE4_APPEND_DATA and ACE4_WRITE_DATA if and only if the write + permission is enabled. + + If a server receives a SETATTR request that it cannot accurately + implement, it should err in the direction of more restricted access, + except in the previously discussed cases of execute and read. For + example, suppose a server cannot distinguish overwriting data from + appending new data, as described in the previous paragraph. If a + client submits an ALLOW ACE where ACE4_APPEND_DATA is set but + ACE4_WRITE_DATA is not (or vice versa), the server should either turn + off ACE4_APPEND_DATA or reject the request with NFS4ERR_ATTRNOTSUPP. + +6.2.1.3.2. ACE4_DELETE vs. ACE4_DELETE_CHILD + + Two access mask bits govern the ability to delete a directory entry: + ACE4_DELETE on the object itself (the "target"), and + ACE4_DELETE_CHILD on the containing directory (the "parent"). + + Many systems also take the "sticky bit" (MODE4_SVTX) on a directory + to allow unlink only to a user that owns either the target or the + parent; on some such systems the decision also depends on whether the + target is writable. + + Servers SHOULD allow unlink if either ACE4_DELETE is permitted on the + target, or ACE4_DELETE_CHILD is permitted on the parent. (Note that + this is true even if the parent or target explicitly denies one of + these permissions.) + + If the ACLs in question neither explicitly ALLOW nor DENY either of + the above, and if MODE4_SVTX is not set on the parent, then the + server SHOULD allow the removal if and only if ACE4_ADD_FILE is + permitted. In the case where MODE4_SVTX is set, the server may also + require the remover to own either the parent or the target, or may + require the target to be writable. + + This allows servers to support something close to traditional UNIX- + like semantics, with ACE4_ADD_FILE taking the place of the write bit. + +6.2.1.4. ACE flag The bitmask constants used for the flag field are as follows: const ACE4_FILE_INHERIT_ACE = 0x00000001; const ACE4_DIRECTORY_INHERIT_ACE = 0x00000002; const ACE4_NO_PROPAGATE_INHERIT_ACE = 0x00000004; const ACE4_INHERIT_ONLY_ACE = 0x00000008; const ACE4_SUCCESSFUL_ACCESS_ACE_FLAG = 0x00000010; const ACE4_FAILED_ACCESS_ACE_FLAG = 0x00000020; const ACE4_IDENTIFIER_GROUP = 0x00000040; A server need not support any of these flags. If the server supports flags that are similar to, but not exactly the same as, these flags, the implementation may define a mapping between the protocol-defined - flags and the implementation-defined flags. Again, the guiding - principle is that the file not appear to be more secure than it - really is. + flags and the implementation-defined flags. For example, suppose a client tries to set an ACE with ACE4_FILE_INHERIT_ACE set but not ACE4_DIRECTORY_INHERIT_ACE. If the server does not support any form of ACL inheritance, the server should reject the request with NFS4ERR_ATTRNOTSUPP. If the server supports a single "inherit ACE" flag that applies to both files and directories, the server may reject the request (i.e., requiring the client to set both the file and directory inheritance flags). The server may also accept the request and silently turn on the ACE4_DIRECTORY_INHERIT_ACE flag. -5.11.4. ACE who +6.2.1.4.1. Discussion of Flag Bits - There are several special identifiers ("who") which need to be - understood universally, rather than in the context of a particular - DNS domain. Some of these identifiers cannot be understood when an - NFS client accesses the server, but have meaning when a local process - accesses the file. The ability to display and modify these - permissions is permitted over NFS, even if none of the access methods - on the server understands the identifiers. + ACE4_FILE_INHERIT_ACE + Any non-directory file in any sub-directory will get this ACE + inherited. - +-----------------+------------------------------------------------+ + ACE4_DIRECTORY_INHERIT_ACE + Can be placed on a directory and indicates that this ACE should be + added to each new directory created. + If this flag is set in an ACE in an ACL attribute to be set on a + non-directory file system object, the operation attempting to set + the ACL SHOULD fail with NFS4ERR_ATTRNOTSUPP. + + ACE4_INHERIT_ONLY_ACE + Can be placed on a directory but does not apply to the directory; + ALLOW and DENY ACEs with this bit set do not affect access to the + directory, and AUDIT and ALARM ACEs with this bit set do not + trigger log or alarm events. Such ACEs only take effect once they + are applied (with this bit cleared) to newly created files and + directories as specified by the above two flags. + If this flag is present on an ACE, but neither + ACE4_DIRECTORY_INHERIT_ACE nor ACE4_FILE_INHERIT_ACE is present, + then an operation attempting to set such an attribute SHOULD fail + with NFS4ERR_ATTRNOTSUPP. + + ACE4_NO_PROPAGATE_INHERIT_ACE + Can be placed on a directory. This flag tells the server that + inheritance of this ACE should stop at newly created child + directories. + + ACE4_SUCCESSFUL_ACCESS_ACE_FLAG + + ACE4_FAILED_ACCESS_ACE_FLAG + The ACE4_SUCCESSFUL_ACCESS_ACE_FLAG (SUCCESS) and + ACE4_FAILED_ACCESS_ACE_FLAG (FAILED) flag bits may be set only on + ACE4_SYSTEM_AUDIT_ACE_TYPE (AUDIT) and ACE4_SYSTEM_ALARM_ACE_TYPE + (ALARM) ACE types. If during the processing of the file's ACL, + the server encounters an AUDIT or ALARM ACE that matches the + principal attempting the OPEN, the server notes that fact, and the + presence, if any, of the SUCCESS and FAILED flags encountered in + the AUDIT or ALARM ACE. Once the server completes the ACL + processing, it then notes if the operation succeeded or failed. + If the operation succeeded, and if the SUCCESS flag was set for a + matching AUDIT or ALARM ACE, then the appropriate AUDIT or ALARM + event occurs. If the operation failed, and if the FAILED flag was + set for the matching AUDIT or ALARM ACE, then the appropriate + AUDIT or ALARM event occurs. Either or both of the SUCCESS or + FAILED can be set, but if neither is set, the AUDIT or ALARM ACE + is not useful. + + The previously described processing applies to ACCESS operations + even when they return NFS4_OK. For the purposes of AUDIT and + ALARM, we consider an ACCESS operation to be a "failure" if it + fails to return a bit that was requested and supported. + + ACE4_IDENTIFIER_GROUP + Indicates that the "who" refers to a GROUP as defined under UNIX + or a GROUP ACCOUNT as defined under Windows. Clients and servers + MUST ignore the ACE4_IDENTIFIER_GROUP flag on ACEs with a who + value equal to one of the special identifiers outlined in + Section 6.2.1.5. + +6.2.1.5. ACE Who + + The "who" field of an ACE is an identifier that specifies the + principal or principals to whom the ACE applies. It may refer to a + user or a group, with the flag bit ACE4_IDENTIFIER_GROUP specifying + which. + + There are several special identifiers which need to be understood + universally, rather than in the context of a particular DNS domain. + Some of these identifiers cannot be understood when an NFS client + accesses the server, but have meaning when a local process accesses + the file. The ability to display and modify these permissions is + permitted over NFS, even if none of the access methods on the server + understands the identifiers. + + +---------------+--------------------------------------------------+ | Who | Description | - +-----------------+------------------------------------------------+ - | "OWNER" | The owner of the file. | - | "GROUP" | The group associated with the file. | - | "EVERYONE" | The world. | - | "INTERACTIVE" | Accessed from an interactive terminal. | - | "NETWORK" | Accessed via the network. | - | "DIALUP" | Accessed as a dialup user to the server. | - | "BATCH" | Accessed from a batch job. | - | "ANONYMOUS" | Accessed without any authentication. | - | "AUTHENTICATED" | Any authenticated user (opposite of ANONYMOUS) | - | "SERVICE" | Access from a system service. | - +-----------------+------------------------------------------------+ + +---------------+--------------------------------------------------+ + | OWNER | The owner of the file | + | GROUP | The group associated with the file. | + | EVERYONE | The world, including the owner and owning group. | + | INTERACTIVE | Accessed from an interactive terminal. | + | NETWORK | Accessed via the network. | + | DIALUP | Accessed as a dialup user to the server. | + | BATCH | Accessed from a batch job. | + | ANONYMOUS | Accessed without any authentication. | + | AUTHENTICATED | Any authenticated user (opposite of ANONYMOUS) | + | SERVICE | Access from a system service. | + +---------------+--------------------------------------------------+ - Table 6 + Table 4 - To avoid conflict, these special identifiers are distinguish by an - appended "@" and should appear in the form "xxxx@" (note: no domain + To avoid conflict, these special identifiers are distinguished by an + appended "@" and should appear in the form "xxxx@" (with no domain name after the "@"). For example: ANONYMOUS@. -5.11.5. Mode Attribute + The ACE4_IDENTIFIER_GROUP flag MUST be ignored on entries with these + special identifiers. When encoding entries with these special + identifiers, the ACE4_IDENTIFIER_GROUP flag SHOULD be set to zero. - The NFS version 4 mode attribute is based on the UNIX mode bits. The +6.2.1.5.1. Discussion of EVERYONE@ + + It is important to note that "EVERYONE@" is not equivalent to the + UNIX "other" entity. This is because, by definition, UNIX "other" + does not include the owner or owning group of a file. "EVERYONE@" + means literally everyone, including the owner or owning group. + +6.2.2. Attribute 33: mode + + The NFSv4.0 mode attribute is based on the UNIX mode bits. The following bits are defined: const MODE4_SUID = 0x800; /* set user id on execution */ const MODE4_SGID = 0x400; /* set group id on execution */ const MODE4_SVTX = 0x200; /* save text even after use */ const MODE4_RUSR = 0x100; /* read permission: owner */ const MODE4_WUSR = 0x080; /* write permission: owner */ const MODE4_XUSR = 0x040; /* execute permission: owner */ const MODE4_RGRP = 0x020; /* read permission: group */ const MODE4_WGRP = 0x010; /* write permission: group */ const MODE4_XGRP = 0x008; /* execute permission: group */ const MODE4_ROTH = 0x004; /* read permission: other */ const MODE4_WOTH = 0x002; /* write permission: other */ const MODE4_XOTH = 0x001; /* execute permission: other */ Bits MODE4_RUSR, MODE4_WUSR, and MODE4_XUSR apply to the principal identified in the owner attribute. Bits MODE4_RGRP, MODE4_WGRP, and - MODE4_XGRP apply to the principals identified in the owner_group - attribute. Bits MODE4_ROTH, MODE4_WOTH, MODE4_XOTH apply to any - principal that does not match that in the owner group, and does not - have a group matching that of the owner_group attribute. + MODE4_XGRP apply to principals identified in the owner_group + attribute but who are not identified in the owner attribute. Bits + MODE4_ROTH, MODE4_WOTH, MODE4_XOTH apply to any principal that does + not match that in the owner attribute, and does not have a group + matching that of the owner_group attribute. - The remaining bits are not defined by this protocol and MUST NOT be - used. The minor version mechanism must be used to define further bit - usage. + Bits within the mode other than those specified above are not defined + by this protocol. A server MUST NOT return bits other than those + defined above in a GETATTR or READDIR operation, and it MUST return + NFS4ERR_INVAL if bits other than those defined above are set in a + SETATTR, CREATE, OPEN, VERIFY or NVERIFY operation. - Note that in UNIX, if a file has the MODE4_SGID bit set and no - MODE4_XGRP bit set, then READ and WRITE must use mandatory file - locking. +6.3. Common Methods -5.11.6. Mode and ACL Attribute + The requirements in this section will be referred to in future + sections, especially Section 6.4. + +6.3.1. Interpreting an ACL + +6.3.1.1. Server Considerations + + The server uses the algorithm described in Section 6.2.1 to determine + whether an ACL allows access to an object. However, the ACL may not + be the sole determiner of access. For example: + + o In the case of a file system exported as read-only, the server may + deny write permissions even though an object's ACL grants it. + + o Server implementations MAY grant ACE4_WRITE_ACL and ACE4_READ_ACL + permissions to prevent a situation from arising in which there is + no valid way to ever modify the ACL. + + o All servers will allow a user the ability to read the data of the + file when only the execute permission is granted (i.e. If the ACL + denies the user the ACE4_READ_DATA access and allows the user + ACE4_EXECUTE, the server will allow the user to read the data of + the file). + + o Many servers have the notion of owner-override in which the owner + of the object is allowed to override accesses that are denied by + the ACL. This may be helpful, for example, to allow users + continued access to open files on which the permissions have + changed. + + o Many servers have the notion of a "superuser" that has privileges + beyond an ordinary user. The superuser may be able to read or + write data or metadata in ways that would not be permitted by the + ACL. + +6.3.1.2. Client Considerations + + Clients SHOULD NOT do their own access checks based on their + interpretation the ACL, but rather use the OPEN and ACCESS operations + to do access checks. This allows the client to act on the results of + having the server determine whether or not access should be granted + based on its interpretation of the ACL. + + Clients must be aware of situations in which an object's ACL will + define a certain access even though the server will not enforce it. + In general, but especially in these situations, the client needs to + do its part in the enforcement of access as defined by the ACL. To + do this, the client MAY send the appropriate ACCESS operation prior + to servicing the request of the user or application in order to + determine whether the user or application should be granted the + access requested. For examples in which the ACL may define accesses + that the server doesn't enforce see Section 6.3.1.1. + +6.3.2. Computing a Mode Attribute from an ACL + + The following method can be used to calculate the MODE4_R*, MODE4_W* + and MODE4_X* bits of a mode attribute, based upon an ACL. + + First, for each of the special identifiers OWNER@, GROUP@, and + EVERYONE@, evaluate the ACL in order, considering only ALLOW and DENY + ACEs for the identifier EVERYONE@ and for the identifier under + consideration. The result of the evaluation will be an NFSv4 ACL + mask showing exactly which bits are permitted to that identifier. + + Then translate the calculated mask for OWNER@, GROUP@, and EVERYONE@ + into mode bits for, respectively, the user, group, and other, as + follows: + + 1. Set the read bit (MODE4_RUSR, MODE4_RGRP, or MODE4_ROTH) if and + only if ACE4_READ_DATA is set in the corresponding mask. + + 2. Set the write bit (MODE4_WUSR, MODE4_WGRP, or MODE4_WOTH) if and + only if ACE4_WRITE_DATA and ACE4_APPEND_DATA are both set in the + corresponding mask. + + 3. Set the execute bit (MODE4_XUSR, MODE4_XGRP, or MODE4_XOTH), if + and only if ACE4_EXECUTE is set in the corresponding mask. + +6.3.2.1. Discussion + + Some server implementations also add bits permitted to named users + and groups to the group bits (MODE4_RGRP, MODE4_WGRP, and + MODE4_XGRP). + + Implementations are discouraged from doing this, because it has been + found to cause confusion for users who see members of a file's group + denied access that the mode bits appear to allow. (The presence of + DENY ACEs may also lead to such behavior, but DENY ACEs are expected + to be more rarely used.) + + The same user confusion seen when fetching the mode also results if + setting the mode does not effectively control permissions for the + owner, group, and other users; this motivates some of the + requirements that follow. + +6.4. Requirements The server that supports both mode and ACL must take care to synchronize the MODE4_*USR, MODE4_*GRP, and MODE4_*OTH bits with the ACEs which have respective who fields of "OWNER@", "GROUP@", and "EVERYONE@" so that the client can see semantically equivalent access permissions exist whether the client asks for owner, owner_group and mode attributes, or for just the ACL. - Because the mode attribute includes bits (e.g., MODE4_SVTX) that have - nothing to do with ACL semantics, it is permitted for clients to - specify both the ACL attribute and mode in the same SETATTR - operation. However, because there is no prescribed order for - processing the attributes in a SETATTR, the client must ensure that - ACL attribute, if specified without mode, would produce the desired - mode bits, and conversely, the mode attribute if specified without - ACL, would produce the desired "OWNER@", "GROUP@", and "EVERYONE@" - ACEs. + In this section, much is made of the methods in Section 6.3.2. Many + requirements refer to this section. But note that the methods have + behaviors specified with "SHOULD". This is intentional, to avoid + invalidating existing implementations that compute the mode according + to the withdrawn POSIX ACL draft (1003.1e draft 17), rather than by + actual permissions on owner, group, and other. -5.11.7. mounted_on_fileid +6.4.1. Setting the mode and/or ACL Attributes - UNIX-based operating environments connect a filesystem into the - namespace by connecting (mounting) the filesystem onto the existing - file object (the mount point, usually a directory) of an existing - filesystem. When the mount point's parent directory is read via an - API like readdir(), the return results are directory entries, each - with a component name and a fileid. The fileid of the mount point's - directory entry will be different from the fileid that the stat() - system call returns. The stat() system call is returning the fileid - of the root of the mounted filesystem, whereas readdir() is returning - the fileid stat() would have returned before any filesystems were - mounted on the mount point. +6.4.1.1. Setting mode and not ACL - Unlike NFS version 3, NFS version 4 allows a client's LOOKUP request - to cross other filesystems. The client detects the filesystem - crossing whenever the filehandle argument of LOOKUP has an fsid - attribute different from that of the filehandle returned by LOOKUP. - A UNIX-based client will consider this a "mount point crossing". - UNIX has a legacy scheme for allowing a process to determine its - current working directory. This relies on readdir() of a mount - point's parent and stat() of the mount point returning fileids as - previously described. The mounted_on_fileid attribute corresponds to - the fileid that readdir() would have returned as described - previously. + When any of the nine low-order mode bits are subject to change, + either because the mode attribute was set or because the + mode_set_masked attribute was set and the mask included one or more + bits from the nine low-order mode bits, and no ACL attribute is + explicitly set, the acl attribute must be modified in accordance with + the updated value of those bits. This must happen even if the value + of the low-order bits is the same after the mode is set as before. - While the NFS version 4 client could simply fabricate a fileid - corresponding to what mounted_on_fileid provides (and if the server - does not support mounted_on_fileid, the client has no choice), there - is a risk that the client will generate a fileid that conflicts with - one that is already assigned to another object in the filesystem. - Instead, if the server can provide the mounted_on_fileid, the - potential for client operational problems in this area is eliminated. + Note that any AUDIT or ALARM ACEs are unaffected by changes to the + mode. - If the server detects that there is no mounted point at the target - file object, then the value for mounted_on_fileid that it returns is - the same as that of the fileid attribute. + In cases in which the permissions bits are subject to change, the acl + attribute MUST be modified such that the mode computed via the method + in Section 6.3.2 yields the low-order nine bits (MODE4_R*, MODE4_W*, + MODE4_X*) of the mode attribute as modified by the attribute change. + The ACL attributes SHOULD also be modified such that: - The mounted_on_fileid attribute is RECOMMENDED, so the server SHOULD - provide it if possible, and for a UNIX-based server, this is - straightforward. Usually, mounted_on_fileid will be requested during - a READDIR operation, in which case it is trivial (at least for UNIX- - based servers) to return mounted_on_fileid since it is equal to the - fileid of a directory entry returned by readdir(). If - mounted_on_fileid is requested in a GETATTR operation, the server - should obey an invariant that has it returning a value that is equal - to the file object's entry in the object's parent directory, i.e., - what readdir() would have returned. Some operating environments - allow a series of two or more filesystems to be mounted onto a single - mount point. In this case, for the server to obey the aforementioned - invariant, it will need to find the base mount point, and not the - intermediate mount points. + 1. If MODE4_RGRP is not set, entities explicitly listed in the ACL + other than OWNER@ and EVERYONE@ SHOULD NOT be granted + ACE4_READ_DATA. -6. Filesystem Migration and Replication + 2. If MODE4_WGRP is not set, entities explicitly listed in the ACL + other than OWNER@ and EVERYONE@ SHOULD NOT be granted + ACE4_WRITE_DATA or ACE4_APPEND_DATA. - With the use of the recommended attribute "fs_locations", the NFS - version 4 server has a method of providing filesystem migration or - replication services. For the purposes of migration and replication, - a filesystem will be defined as all files that share a given fsid - (both major and minor values are the same). + 3. If MODE4_XGRP is not set, entities explicitly listed in the ACL + other than OWNER@ and EVERYONE@ SHOULD NOT be granted + ACE4_EXECUTE. - The fs_locations attribute provides a list of filesystem locations. - These locations are specified by providing the server name (either - DNS domain or IP address) and the path name representing the root of - the filesystem. Depending on the type of service being provided, the - list will provide a new location or a set of alternate locations for - the filesystem. The client will use this information to redirect its - requests to the new server. + Access mask bits other those listed above, appearing in ALLOW ACEs, + MAY also be disabled. -6.1. Replication + Note that ACEs with the flag ACE4_INHERIT_ONLY_ACE set do not affect + the permissions of the ACL itself, nor do ACEs of the type AUDIT and + ALARM. As such, it is desirable to leave these ACEs unmodified when + modifying the ACL attributes. - It is expected that filesystem replication will be used in the case - of read-only data. Typically, the filesystem will be replicated on - two or more servers. The fs_locations attribute will provide the - list of these locations to the client. On first access of the - filesystem, the client should obtain the value of the fs_locations - attribute. If, in the future, the client finds the server - unresponsive, the client may attempt to use another server specified - by fs_locations. + Also note that the requirement may be met by discarding the acl in + favor of an ACL that represents the mode and only the mode. This is + permitted, but it is preferable for a server to preserve as much of + the ACL as possible without violating the above requirements. + Discarding the ACL makes it effectively impossible for a file created + with a mode attribute to inherit an ACL (see Section 6.4.3). - If applicable, the client must take the appropriate steps to recover - valid filehandles from the new server. This is described in more - detail in the following sections. +6.4.1.2. Setting ACL and not mode -6.2. Migration + When setting the acl and not setting the mode or mode_set_masked + attributes, the permission bits of the mode need to be derived from + the ACL. In this case, the ACL attribute SHOULD be set as given. + The nine low-order bits of the mode attribute (MODE4_R*, MODE4_W*, + MODE4_X*) MUST be modified to match the result of the method + Section 6.3.2. The three high-order bits of the mode (MODE4_SUID, + MODE4_SGID, MODE4_SVTX) SHOULD remain unchanged. - Filesystem migration is used to move a filesystem from one server to - another. Migration is typically used for a filesystem that is - writable and has a single copy. The expected use of migration is for - load balancing or general resource reallocation. The protocol does - not specify how the filesystem will be moved between servers. This - server-to-server transfer mechanism is left to the server - implementor. However, the method used to communicate the migration - event between client and server is specified here. +6.4.1.3. Setting both ACL and mode - Once the servers participating in the migration have completed the - move of the filesystem, the error NFS4ERR_MOVED will be returned for - subsequent requests received by the original server. The - NFS4ERR_MOVED error is returned for all operations except PUTFH and - GETATTR. Upon receiving the NFS4ERR_MOVED error, the client will - obtain the value of the fs_locations attribute. The client will then - use the contents of the attribute to redirect its requests to the - specified server. To facilitate the use of GETATTR, operations such - as PUTFH must also be accepted by the server for the migrated file - system's filehandles. Note that if the server returns NFS4ERR_MOVED, - the server MUST support the fs_locations attribute. + When setting both the mode (includes use of either the mode attribute + or the mode_set_masked attribute) and the acl attribute in the same + operation, the attributes MUST be applied in this order: mode (or + mode_set_masked), then ACL. The mode-related attribute is set as + given, then the ACL attribute is set as given, possibly changing the + final mode, as described above in Section 6.4.1.2. - If the client requests more attributes than just fs_locations, the - server may return fs_locations only. This is to be expected since - the server has migrated the filesystem and may not have a method of - obtaining additional attribute data. +6.4.2. Retrieving the mode and/or ACL Attributes - The server implementor needs to be careful in developing a migration - solution. The server must consider all of the state information - clients may have outstanding at the server. This includes but is not - limited to locking/share state, delegation state, and asynchronous - file writes which are represented by WRITE and COMMIT verifiers. The - server should strive to minimize the impact on its clients during and - after the migration process. + This section applies only to servers that support both the mode and + ACL attributes. -6.3. Interpretation of the fs_locations Attribute + Some server implementations may have a concept of "objects without + ACLs", meaning that all permissions are granted and denied according + to the mode attribute, and that no ACL attribute is stored for that + object. If an ACL attribute is requested of such a server, the + server SHOULD return an ACL that does not conflict with the mode; + that is to say, the ACL returned SHOULD represent the nine low-order + bits of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) as + described in Section 6.3.2. - The fs_location attribute is structured in the following way: + For other server implementations, the ACL attribute is always present + for every object. Such servers SHOULD store at least the three high- + order bits of the mode attribute (MODE4_SUID, MODE4_SGID, + MODE4_SVTX). The server SHOULD return a mode attribute if one is + requested, and the low-order nine bits of the mode (MODE4_R*, + MODE4_W*, MODE4_X*) MUST match the result of applying the method in + Section 6.3.2 to the ACL attribute. + +6.4.3. Creating New Objects + + If a server supports any ACL attributes, it may use the ACL + attributes on the parent directory to compute an initial ACL + attribute for a newly created object. This will be referred to as + the inherited ACL within this section. The act of adding one or more + ACEs to the inherited ACL that are based upon ACEs in the parent + directory's ACL will be referred to as inheriting an ACE within this + section. + + Implementors should standardize on what the behavior of CREATE and + OPEN must be depending on the presence or absence of the mode and ACL + attributes. + + 1. If just the mode is given in the call: + + In this case, inheritance SHOULD take place, but the mode MUST be + applied to the inherited ACL as described in Section 6.4.1.1, + thereby modifying the ACL. + + 2. If just the ACL is given in the call: + + In this case, inheritance SHOULD NOT take place, and the ACL as + defined in the CREATE or OPEN will be set without modification, + and the mode modified as in Section 6.4.1.2 + + 3. If both mode and ACL are given in the call: + + In this case, inheritance SHOULD NOT take place, and both + attributes will be set as described in Section 6.4.1.3. + + 4. If neither mode nor ACL are given in the call: + + In the case where an object is being created without any initial + attributes at all, e.g. an OPEN operation with an opentype4 of + OPEN4_CREATE and a createmode4 of EXCLUSIVE4, inheritance SHOULD + NOT take place. Instead, the server SHOULD set permissions to + deny all access to the newly created object. It is expected that + the appropriate client will set the desired attributes in a + subsequent SETATTR operation, and the server SHOULD allow that + operation to succeed, regardless of what permissions the object + is created with. For example, an empty ACL denies all + permissions, but the server should allow the owner's SETATTR to + succeed even though WRITE_ACL is implicitly denied. + + In other cases, inheritance SHOULD take place, and no + modifications to the ACL will happen. The mode attribute, if + supported, MUST be as computed in Section 6.3.2, with the + MODE4_SUID, MODE4_SGID and MODE4_SVTX bits clear. If no + inheritable ACEs exist on the parent directory, the rules for + creating acl attributes are implementation defined. + +6.4.3.1. The Inherited ACL + + If the object being created is not a directory, the inherited ACL + SHOULD NOT inherit ACEs from the parent directory ACL unless the + ACE4_FILE_INHERIT_FLAG is set. + + If the object being created is a directory, the inherited ACL should + inherit all inheritable ACEs from the parent directory, those that + have ACE4_FILE_INHERIT_ACE or ACE4_DIRECTORY_INHERIT_ACE flag set. + If the inheritable ACE has ACE4_FILE_INHERIT_ACE set, but + ACE4_DIRECTORY_INHERIT_ACE is clear, the inherited ACE on the newly + created directory MUST have the ACE4_INHERIT_ONLY_ACE flag set to + prevent the directory from being affected by ACEs meant for non- + directories. + + When a new directory is created, the server MAY split any inherited + ACE which is both inheritable and effective (in other words, which + has neither ACE4_INHERIT_ONLY_ACE nor ACE4_NO_PROPAGATE_INHERIT_ACE + set), into two ACEs, one with no inheritance flags, and one with + ACE4_INHERIT_ONLY_ACE set. This makes it simpler to modify the + effective permissions on the directory without modifying the ACE + which is to be inherited to the new directory's children. + +7. Multi-Server Namespace + + NFSv4 supports attributes that allow a namespace to extend beyond the + boundaries of a single server. It is RECOMMENDED that clients and + servers support construction of such multi-server namespaces. Use of + such multi-server namespaces is OPTIONAL however, and for many + purposes, single-server namespace are perfectly acceptable. Use of + multi-server namespaces can provide many advantages, however, by + separating a file system's logical position in a namespace from the + (possibly changing) logistical and administrative considerations that + result in particular file systems being located on particular + servers. + +7.1. Location Attributes + + NFSv4 contains RECOMMENDED attributes that allow file systems on one + server to be associated with one or more instances of that file + system on other servers. These attributes specify such file system + instances by specifying a server address target (either as a DNS name + representing one or more IP addresses or as a literal IP address) + together with the path of that file system within the associated + single-server namespace. + + The fs_locations RECOMMENDED attribute allows specification of the + file system locations where the data corresponding to a given file + system may be found. + +7.2. File System Presence or Absence + + A given location in an NFSv4 namespace (typically but not necessarily + a multi-server namespace) can have a number of file system instance + locations associated with it via the fs_locations attribute. There + may also be an actual current file system at that location, + accessible via normal namespace operations (e.g. LOOKUP). In this + case, the file system is said to be "present" at that position in the + namespace and clients will typically use it, reserving use of + additional locations specified via the location-related attributes to + situations in which the principal location is no longer available. + + When there is no actual file system at the namespace location in + question, the file system is said to be "absent". An absent file + system contains no files or directories other than the root. Any + reference to it, except to access a small set of attributes useful in + determining alternate locations, will result in an error, + NFS4ERR_MOVED. Note that if the server ever returns the error + NFS4ERR_MOVED, it MUST support the fs_locations attribute. + + While the error name suggests that we have a case of a file system + which once was present, and has only become absent later, this is + only one possibility. A position in the namespace may be permanently + absent with the set of file system(s) designated by the location + attributes being the only realization. The name NFS4ERR_MOVED + reflects an earlier, more limited conception of its function, but + this error will be returned whenever the referenced file system is + absent, whether it has moved or not. + + Except in the case of GETATTR-type operations (to be discussed + later), when the current filehandle at the start of an operation is + within an absent file system, that operation is not performed and the + error NFS4ERR_MOVED returned, to indicate that the file system is + absent on the current server. + + Because a GETFH cannot succeed if the current filehandle is within an + absent file system, filehandles within an absent file system cannot + be transferred to the client. When a client does have filehandles + within an absent file system, it is the result of obtaining them when + the file system was present, and having the file system become absent + subsequently. + + It should be noted that because the check for the current filehandle + being within an absent file system happens at the start of every + operation, operations that change the current filehandle so that it + is within an absent file system will not result in an error. This + allows such combinations as PUTFH-GETATTR and LOOKUP-GETATTR to be + used to get attribute information, particularly location attribute + information, as discussed below. + +7.3. Getting Attributes for an Absent File System + + When a file system is absent, most attributes are not available, but + it is necessary to allow the client access to the small set of + attributes that are available, and most particularly that which gives + information about the correct current locations for this file system, + fs_locations. + +7.3.1. GETATTR Within an Absent File System + + As mentioned above, an exception is made for GETATTR in that + attributes may be obtained for a filehandle within an absent file + system. This exception only applies if the attribute mask contains + at least the fs_locations attribute bit, which indicates the client + is interested in a result regarding an absent file system. If it is + not requested, GETATTR will result in an NFS4ERR_MOVED error. + + When a GETATTR is done on an absent file system, the set of supported + attributes is very limited. Many attributes, including those that + are normally REQUIRED, will not be available on an absent file + system. In addition to the fs_locations attribute, the following + attributes SHOULD be available on absent file systems, in the case of + RECOMMENDED attributes at least to the same degree that they are + available on present file systems. + + fsid: This attribute should be provided so that the client can + determine file system boundaries, including, in particular, the + boundary between present and absent file systems. This value must + be different from any other fsid on the current server and need + have no particular relationship to fsids on any particular + destination to which the client might be directed. + + mounted_on_fileid: For objects at the top of an absent file system + this attribute needs to be available. Since the fileid is one + which is within the present parent file system, there should be no + need to reference the absent file system to provide this + information. + + Other attributes SHOULD NOT be made available for absent file + systems, even when it is possible to provide them. The server should + not assume that more information is always better and should avoid + gratuitously providing additional information. + + When a GETATTR operation includes a bit mask for the attribute + fs_locations, but where the bit mask includes attributes which are + not supported, GETATTR will not return an error, but will return the + mask of the actual attributes supported with the results. + + Handling of VERIFY/NVERIFY is similar to GETATTR in that if the + attribute mask does not include fs_locations the error NFS4ERR_MOVED + will result. It differs in that any appearance in the attribute mask + of an attribute not supported for an absent file system (and note + that this will include some normally REQUIRED attributes), will also + cause an NFS4ERR_MOVED result. + +7.3.2. READDIR and Absent File Systems + + A READDIR performed when the current filehandle is within an absent + file system will result in an NFS4ERR_MOVED error, since, unlike the + case of GETATTR, no such exception is made for READDIR. + + Attributes for an absent file system may be fetched via a READDIR for + a directory in a present file system, when that directory contains + the root directories of one or more absent file systems. In this + case, the handling is as follows: + + o If the attribute set requested includes fs_locations, then + fetching of attributes proceeds normally and no NFS4ERR_MOVED + indication is returned, even when the rdattr_error attribute is + requested. + + o If the attribute set requested does not include fs_locations, then + if the rdattr_error attribute is requested, each directory entry + for the root of an absent file system, will report NFS4ERR_MOVED + as the value of the rdattr_error attribute. + + o If the attribute set requested does not include either of the + attributes fs_locations or rdattr_error then the occurrence of the + root of an absent file system within the directory will result in + the READDIR failing with an NFS4ERR_MOVED error. + + o The unavailability of an attribute because of a file system's + absence, even one that is ordinarily REQUIRED, does not result in + any error indication. The set of attributes returned for the root + directory of the absent file system in that case is simply + restricted to those actually available. + +7.4. Uses of Location Information + + The location-bearing attribute of fs_locations provides, together + with the possibility of absent file systems, a number of important + facilities in providing reliable, manageable, and scalable data + access. + + When a file system is present, these attributes can provide + alternative locations, to be used to access the same data, in the + event of server failures, communications problems, or other + difficulties that make continued access to the current file system + impossible or otherwise impractical. Under some circumstances + multiple alternative locations may be used simultaneously to provide + higher performance access to the file system in question. Provision + of such alternate locations is referred to as "replication" although + there are cases in which replicated sets of data are not in fact + present, and the replicas are instead different paths to the same + data. + + When a file system is present and becomes absent, clients can be + given the opportunity to have continued access to their data, at an + alternate location. In this case, a continued attempt to use the + data in the now-absent file system will result in an NFS4ERR_MOVED + error and at that point the successor locations (typically only one + but multiple choices are possible) can be fetched and used to + continue access. Transfer of the file system contents to the new + location is referred to as "migration", but it should be kept in mind + that there are cases in which this term can be used, like + "replication", when there is no actual data migration per se. + + Where a file system was not previously present, specification of file + system location provides a means by which file systems located on one + server can be associated with a namespace defined by another server, + thus allowing a general multi-server namespace facility. A + designation of such a location, in place of an absent file system, is + called a "referral". + + Because client support for location-related attributes is OPTIONAL, a + server may (but is not required to) take action to hide migration and + referral events from such clients, by acting as a proxy, for example. + +7.4.1. File System Replication + + The fs_locations attribute provides alternative locations, to be used + to access data in place of or in addition to the current file system + instance. On first access to a file system, the client should obtain + the value of the set of alternate locations by interrogating the + fs_locations attribute. + + In the event that server failures, communications problems, or other + difficulties make continued access to the current file system + impossible or otherwise impractical, the client can use the alternate + locations as a way to get continued access to its data. Multiple + locations may be used simultaneously, to provide higher performance + through the exploitation of multiple paths between client and target + file system. + + The alternate locations may be physical replicas of the (typically + read-only) file system data, or they may reflect alternate paths to + the same server or provide for the use of various forms of server + clustering in which multiple servers provide alternate ways of + accessing the same physical file system. + + Multiple server addresses, whether they are derived from a single + entry with a DNS name representing a set of IP addresses, or from + multiple entries each with its own server address may correspond to + the same actual server. + +7.4.2. File System Migration + + When a file system is present and becomes absent, clients can be + given the opportunity to have continued access to their data, at an + alternate location, as specified by the fs_locations attribute. + Typically, a client will be accessing the file system in question, + get an NFS4ERR_MOVED error, and then use the fs_locations attribute + to determine the new location of the data. + + Such migration can be helpful in providing load balancing or general + resource reallocation. The protocol does not specify how the file + system will be moved between servers. It is anticipated that a + number of different server-to-server transfer mechanisms might be + used with the choice left to the server implementer. The NFSv4 + protocol specifies the method used to communicate the migration event + between client and server. + + The new location may be an alternate communication path to the same + server, or, in the case of various forms of server clustering, + another server providing access to the same physical file system. + + When an alternate location is designated as the target for migration, + it must designate the same data. Where file systems are writable, a + change made on the original file system must be visible on all + migration targets. Where a file system is not writable but + represents a read-only copy (possibly periodically updated) of a + writable file system, similar requirements apply to the propagation + of updates. Any change visible in the original file system must + already be effected on all migration targets, to avoid any + possibility, that a client in effecting a transition to the migration + target will see any reversion in file system state. + +7.4.3. Referrals + + Referrals provide a way of placing a file system in a location within + the namespace essentially without respect to its physical location on + a given server. This allows a single server or a set of servers to + present a multi-server namespace that encompasses file systems + located on multiple servers. Some likely uses of this include + establishment of site-wide or organization-wide namespaces, or even + knitting such together into a truly global namespace. + + Referrals occur when a client determines, upon first referencing a + position in the current namespace, that it is part of a new file + system and that the file system is absent. When this occurs, + typically by receiving the error NFS4ERR_MOVED, the actual location + or locations of the file system can be determined by fetching the + fs_locations attribute. + + The locations-related attribute may designate a single file system + location or multiple file system locations, to be selected based on + the needs of the client. + + Use of multi-server namespaces is enabled by NFSv4 but is not + required. The use of multi-server namespaces and their scope will + depend on the applications used, and system administration + preferences. + + Multi-server namespaces can be established by a single server + providing a large set of referrals to all of the included file + systems. Alternatively, a single multi-server namespace may be + administratively segmented with separate referral file systems (on + separate servers) for each separately-administered portion of the + namespace. Any segment or the top-level referral file system may use + replicated referral file systems for higher availability. + + Generally, multi-server namespaces are for the most part uniform, in + that the same data made available to one client at a given location + in the namespace is made available to all clients at that location. + +7.5. Location Entries and Server Identity + + As mentioned above, a single location entry may have a server address + target in the form of a DNS name which may represent multiple IP + addresses, while multiple location entries may have their own server + address targets, that reference the same server. + + When multiple addresses for the same server exist, the client may + assume that for each file system in the namespace of a given server + network address, there exist file systems at corresponding namespace + locations for each of the other server network addresses. It may do + this even in the absence of explicit listing in fs_locations. Such + corresponding file system locations can be used as alternate + locations, just as those explicitly specified via the fs_locations + attribute. + + If a single location entry designates multiple server IP addresses, + the client cannot assume that these addresses are multiple paths to + the same server. In most case they will be, but the client MUST + verify that before acting on that assumption. When two server + addresses are designated by a single location entry and they + correspond to different servers, this normally indicates some sort of + misconfiguration, and so the client should avoid use such location + entries when alternatives are available. When they are not, clients + should pick one of IP addresses and use it, without using others that + are not directed to the same server. + +7.6. Additional Client-side Considerations + + When clients make use of servers that implement referrals, + replication, and migration, care should be taken so that a user who + mounts a given file system that includes a referral or a relocated + file system continues to see a coherent picture of that user-side + file system despite the fact that it contains a number of server-side + file systems which may be on different servers. + + One important issue is upward navigation from the root of a server- + side file system to its parent (specified as ".." in UNIX), in the + case in which it transitions to that file system as a result of + referral, migration, or a transition as a result of replication. + When the client is at such a point, and it needs to ascend to the + parent, it must go back to the parent as seen within the multi-server + namespace rather issuing a LOOKUPP call to the server, which would + result in the parent within that server's single-server namespace. + In order to do this, the client needs to remember the filehandles + that represent such file system roots, and use these instead of + issuing a LOOKUPP to the current server. This will allow the client + to present to applications a consistent namespace, where upward + navigation and downward navigation are consistent. + + Another issue concerns refresh of referral locations. When referrals + are used extensively, they may change as server configurations + change. It is expected that clients will cache information related + to traversing referrals so that future client side requests are + resolved locally without server communication. This is usually + rooted in client-side name lookup caching. Clients should + periodically purge this data for referral points in order to detect + changes in location information. When the change_policy attribute + changes for directories that hold referral entries or for the + referral entries themselves, clients should consider any associated + cached referral information to be out of date. + +7.7. Effecting File System Transitions + + Transitions between file system instances, whether due to switching + between replicas upon server unavailability, or in response to + server-initiated migration events are best dealt with together. This + is so even though for the server, pragmatic considerations will + normally force different implementation strategies for planned and + unplanned transitions. Even though the prototypical use cases of + replication and migration contain distinctive sets of features, when + all possibilities for these operations are considered, there is an + underlying unity of these operations, from the client's point of + view, that makes treating them together desirable. + + A number of methods are possible for servers to replicate data and to + track client state in order to allow clients to transition between + file system instances with a minimum of disruption. Such methods + vary between those that use inter-server clustering techniques to + limit the changes seen by the client, to those that are less + aggressive, use more standard methods of replicating data, and impose + a greater burden on the client to adapt to the transition. + + The NFSv4 protocol does not impose choices on clients and servers + with regard to that spectrum of transition methods. The NFSv4.0 + protocol does not provide the servers a means of communicating the + transiation methods. In the NFSv4.1 protocol [27], an additional + attribute "fs_locations_info" is presented, which will define the + specific choices that can be made, how these choices are communicated + to the client and how the client is to deal with any discontinuities. + + In the sections below, references will be made to various possible + server issues as a way of illustrating the transition scenarios that + clients may deal with. The intent here is not to define or limit + server implementations but rather to illustrate the range of issues + that clients may face. Again, as the NFSv4.0 protocol does not have + an explict means of communicating these issues to the client, the + intent is to document the problems that can be faced in a multi- + server name space and allow the client to use the inferred + transitions available via fs_locations and other attributes (see + Section 7.9.1). + + In the discussion below, references will be made to a file system + having a particular property or of two file systems (typically the + source and destination) belonging to a common class of any of several + types. Two file systems that belong to such a class share some + important aspect of file system behavior that clients may depend upon + when present, to easily effect a seamless transition between file + system instances. Conversely, where the file systems do not belong + to such a common class, the client has to deal with various sorts of + implementation discontinuities which may cause performance or other + issues in effecting a transition. + + While fs_locations is available, default assumptions with regard to + such classifications have to be inferred (see Section 7.9.1 for + details). + + In cases in which one server is expected to accept opaque values from + the client that originated from another server, the servers SHOULD + encode the "opaque" values in big endian byte order. If this is + done, servers acting as replicas or immigrating file systems will be + able to parse values like stateids, directory cookies, filehandles, + etc. even if their native byte order is different from that of other + servers cooperating in the replication and migration of the file + system. + +7.7.1. File System Transitions and Simultaneous Access + + When a single file system may be accessed at multiple locations, + whether this is because of an indication of file system identity as + reported by the fs_locations attribute, the client will, depending on + specific circumstances as discussed below, either: + + o The client accesses multiple instances simultaneously, as + representing alternate paths to the same data and metadata. + + o The client accesses one instance (or set of instances) and then + transitions to an alternative instance (or set of instances) as a + result of network issues, server unresponsiveness, or server- + directed migration. + +7.7.2. Filehandles and File System Transitions + + There are a number of ways in which filehandles can be handled across + a file system transition. These can be divided into two broad + classes depending upon whether the two file systems across which the + transition happens share sufficient state to effect some sort of + continuity of file system handling. + + When there is no such co-operation in filehandle assignment, the two + file systems are reported as being in different _handle_ classes. In + this case, all filehandles are assumed to expire as part of the file + system transition. Note that this behavior does not depend on + fh_expire_type attribute and depends on the specification of the + FH4_VOL_MIGRATION bit. + + When there is co-operation in filehandle assignment, the two file + systems are reported as being in the same _handle_ classes. In this + case, persistent filehandles remain valid after the file system + transition, while volatile filehandles (excluding those that are only + volatile due to the FH4_VOL_MIGRATION bit) are subject to expiration + on the target server. + +7.7.3. Fileids and File System Transitions + + The issue of continuity of fileids in the event of a file system + transition needs to be addressed. The general expectation had been + that in situations in which the two file system instances are created + by a single vendor using some sort of file system image copy, fileids + will be consistent across the transition while in the analogous + multi-vendor transitions they will not. This poses difficulties, + especially for the client without special knowledge of the transition + mechanisms adopted by the server. Note that although fileid is not a + REQUIRED attribute, many servers support fileids and many clients + provide API's that depend on fileids. + + It is important to note that while clients themselves may have no + trouble with a fileid changing as a result of a file system + transition event, applications do typically have access to the fileid + (e.g. via stat), and the result of this is that an application may + work perfectly well if there is no file system instance transition or + if any such transition is among instances created by a single vendor, + yet be unable to deal with the situation in which a multi-vendor + transition occurs, at the wrong time. + + Providing the same fileids in a multi-vendor (multiple server + vendors) environment has generally been held to be quite difficult. + While there is work to be done, it needs to be pointed out that this + difficulty is partly self-imposed. Servers have typically identified + fileid with inode number, i.e. with a quantity used to find the file + in question. This identification poses special difficulties for + migration of a file system between vendors where assigning the same + index to a given file may not be possible. Note here that a fileid + is not required to be useful to find the file in question, only that + it is unique within the given file system. Servers prepared to + accept a fileid as a single piece of metadata and store it apart from + the value used to index the file information can relatively easily + maintain a fileid value across a migration event, allowing a truly + transparent migration event. + + In any case, where servers can provide continuity of fileids, they + should, and the client should be able to find out that such + continuity is available and take appropriate action. Information + about the continuity (or lack thereof) of fileids across a file + system transition is represented by specifying whether the file + systems in question are of the same _fileid_ class. + + Note that when consistent fileids do not exist across a transition + (either because there is no continuity of fileids or because fileid + is not a supported attribute on one of instances involved), and there + are no reliable filehandles across a transition event (either because + there is no filehandle continuity or because the filehandles are + volatile), the client is in a position where it cannot verify that + files it was accessing before the transition are the same objects. + It is forced to assume that no object has been renamed, and, unless + there are guarantees that provide this (e.g. the file system is read- + only), problems for applications may occur. Therefore, use of such + configurations should be limited to situations where the problems + that this may cause can be tolerated. + +7.7.4. Fsids and File System Transitions + + Since fsids are generally only unique within a per-server basis, it + is likely that they will change during a file system transition. + Clients should not make the fsids received from the server visible to + applications since they may not be globally unique, and because they + may change during a file system transition event. Applications are + best served if they are isolated from such transitions to the extent + possible. + +7.7.5. The Change Attribute and File System Transitions + + Since the change attribute is defined as a server-specific one, + change attributes fetched from one server are normally presumed to be + invalid on another server. Such a presumption is troublesome since + it would invalidate all cached change attributes, requiring + refetching. Even more disruptive, the absence of any assured + continuity for the change attribute means that even if the same value + is retrieved on refetch no conclusions can drawn as to whether the + object in question has changed. The identical change attribute could + be merely an artifact of a modified file with a different change + attribute construction algorithm, with that new algorithm just + happening to result in an identical change value. + + When the two file systems have consistent change attribute formats, + and we say that they are in the same _change_ class, the client may + assume a continuity of change attribute construction and handle this + situation just as it would be handled without any file system + transition. + +7.7.6. Lock State and File System Transitions + + In a file system transition, the client needs to handle cases in + which the two servers have cooperated in state management and in + which they have not. Cooperation by two servers in state management + requires coordination of client IDs. Before the client attempts to + use a client ID associated with one server in a request to the server + of the other file system, it must eliminate the possibility that two + non-cooperating servers have assigned the same client ID by accident. + + In the case of migration, the servers involved in the migration of a + file system SHOULD transfer all server state from the original to the + new server. When this is done, it must be done in a way that is + transparent to the client. With replication, such a degree of common + state is typically not the case. + + This state transfer will reduce disruption to the client when a file + system transition occurs. If the servers are successful in + transferring all state, the client can attempt to establish sessions + associated with the client ID used for the source file system + instance. If the server accepts that as a valid client ID, then the + client may use the existing stateids associated with that client ID + for the old file system instance in connection with that same client + ID in connection with the transitioned file system instance. + + File systems co-operating in state management may actually share + state or simply divide the identifier space so as to recognize (and + reject as stale) each other's stateids and client IDs. Servers which + do share state may not do so under all conditions or at all times. + The requirement for the server is that if it cannot be sure in + accepting a client ID that it reflects the locks the client was + given, it must treat all associated state as stale and report it as + such to the client. + + The client must establish a new client ID on the destination, if it + does not have one already, and reclaim locks if possible. In this + case, old stateids and client IDs should not be presented to the new + server since there is no assurance that they will not conflict with + IDs valid on that server. + + When actual locks are not known to be maintained, the destination + server may establish a grace period specific to the given file + system, with non-reclaim locks being rejected for that file system, + even though normal locks are being granted for other file systems. + Clients should not infer the absence of a grace period for file + systems being transitioned to a server from responses to requests for + other file systems. + + In the case of lock reclamation for a given file system after a file + system transition, edge conditions can arise similar to those for + reclaim after server restart (although in the case of the planned + state transfer associated with migration, these can be avoided by + securely recording lock state as part of state migration). Unless + the destination server can guarantee that locks will not be + incorrectly granted, the destination server should not allow lock + reclaims and avoid establishing a grace period. (See Section 9.14 + for further details.) + + Information about client identity may be propagated between servers + in the form of client_owner4 and associated verifiers, under the + assumption that the client presents the same values to all the + servers with which it deals. + + Servers are encouraged to provide facilities to allow locks to be + reclaimed on the new server after a file system transition. Often + such facilities may not be available and client should be prepared to + re-obtain locks, even though it is possible that the client may have + its LOCK or OPEN request denied due to a conflicting lock. + + The consequences of having no facilities available to reclaim locks + on the sew server will depend on the type of environment. In some + environments, such as the transition between read-only file systems, + such denial of locks should not pose large difficulties in practice. + When an attempt to re-establish a lock on a new server is denied, the + client should treat the situation as if its original lock had been + revoked. Note that when the lock is granted, the client cannot + assume that no conflicting lock could have been granted in the + interim. Where change attribute continuity is present, the client + may check the change attribute to check for unwanted file + modifications. Where even this is not available, and the file system + is not read-only, a client may reasonably treat all pending locks as + having been revoked. + +7.7.6.1. Transitions and the Lease_time Attribute + + In order that the client may appropriately manage its leases in the + case of a file system transition, the destination server must + establish proper values for the lease_time attribute. + + When state is transferred transparently, that state should include + the correct value of the lease_time attribute. The lease_time + attribute on the destination server must never be less than that on + the source since this would result in premature expiration of leases + granted by the source server. Upon transitions in which state is + transferred transparently, the client is under no obligation to re- + fetch the lease_time attribute and may continue to use the value + previously fetched (on the source server). + + If state has not been transferred transparently because the client ID + is rejected when presented to the new server, the client should fetch + the value of lease_time on the new (i.e. destination) server, and use + it for subsequent locking requests. However the server must respect + a grace period at least as long as the lease_time on the source + server, in order to ensure that clients have ample time to reclaim + their lock before potentially conflicting non-reclaimed locks are + granted. + +7.7.7. Write Verifiers and File System Transitions + + In a file system transition, the two file systems may be clustered in + the handling of unstably written data. When this is the case, and + the two file systems belong to the same _write-verifier_ class, write + verifiers returned from one system may be compared to those returned + by the other and superfluous writes avoided. + + When two file systems belong to different _write-verifier_ classes, + any verifier generated by one must not be compared to one provided by + the other. Instead, it should be treated as not equal even when the + values are identical. + +7.7.8. Readdir Cookies and Verifiers and File System Transitions + + In a file system transition, the two file systems may be consistent + in their handling of READDIR cookies and verifiers. When this is the + case, and the two file systems belong to the same _readdir_ class, + READDIR cookies and verifiers from one system may be recognized by + the other and READDIR operations started on one server may be validly + continued on the other, simply by presenting the cookie and verifier + returned by a READDIR operation done on the first file system to the + second. + + When two file systems belong to different _readdir_ classes, any + READDIR cookie and verifier generated by one is not valid on the + second, and must not be presented to that server by the client. The + client should act as if the verifier was rejected. + +7.7.9. File System Data and File System Transitions + + When multiple replicas exist and are used simultaneously or in + succession by a client, applications using them will normally expect + that they contain data the same data or data which is consistent with + the normal sorts of changes that are made by other clients updating + the data of the file system. (with metadata being the same to the + degree inferred by the fs_locations attribute). However, when + multiple file systems are presented as replicas of one another, the + precise relationship between the data of one and the data of another + is not, as a general matter, specified by the NFSv4 protocol. It is + quite possible to present as replicas file systems where the data of + those file systems is sufficiently different that some applications + have problems dealing with the transition between replicas. The + namespace will typically be constructed so that applications can + choose an appropriate level of support, so that in one position in + the namespace a varied set of replicas will be listed while in + another only those that are up-to-date may be considered replicas. + The protocol does define three special cases of the relationship + among replicas to be specified by the server and relied upon by + clients: + + o When multiple server addresses correspond to the same actual + server, the client may depend on the fact that changes to data, + metadata, or locks made on one file system are immediately + reflected on others. + + o When multiple replicas exist and are used simultaneously by a + client, they must designate the same data. Where file systems are + writable, a change made on one instance must be visible on all + instances, immediately upon the earlier of the return of the + modifying requester or the visibility of that change on any of the + associated replicas. This allows a client to use these replicas + simultaneously without any special adaptation to the fact that + there are multiple replicas. In this case, locks, whether shared + or byte-range, and delegations obtained one replica are + immediately reflected on all replicas, even though these locks + will be managed under a set of client IDs. + + o When one replica is designated as the successor instance to + another existing instance after return NFS4ERR_MOVED (i.e. the + case of migration), the client may depend on the fact that all + changes securely made to data (uncommitted writes are dealt with + in Section 7.7.7) on the original instance are made to the + successor image. + + o Where a file system is not writable but represents a read-only + copy (possibly periodically updated) of a writable file system, + clients have similar requirements with regard to the propagation + of updates. They may need a guarantee that any change visible on + the original file system instance must be immediately visible on + any replica before the client transitions access to that replica, + in order to avoid any possibility that a client, in effecting a + transition to a replica, will see any reversion in file system + state. Since these file systems are presumed not to be suitable + for simultaneous use, there is no specification of how locking is + handled and it generally will be the case that locks obtained one + file system will be separate from those on others. Since these + are going to be read-only file systems, this is not expected to + pose an issue for clients or applications. + +7.8. Effecting File System Referrals + + Referrals are effected when an absent file system is encountered, and + one or more alternate locations are made available by the + fs_locations attribute. The client will typically get an + NFS4ERR_MOVED error, fetch the appropriate location information and + proceed to access the file system on a different server, even though + it retains its logical position within the original namespace. + Referrals differ from migration events in that they happen only when + the client has not previously referenced the file system in question + (so there is nothing to transition). Referrals can only come into + effect when an absent file system is encountered at its root. + + The examples given in the sections below are somewhat artificial in + that an actual client will not typically do a multi-component lookup, + but will have cached information regarding the upper levels of the + name hierarchy. However, these example are chosen to make the + required behavior clear and easy to put within the scope of a small + number of requests, without getting unduly into details of how + specific clients might choose to cache things. + +7.8.1. Referral Example (LOOKUP) + + Let us suppose that the following COMPOUND is sent in an environment + in which /this/is/the/path is absent from the target server. This + may be for a number of reasons. It may be the case that the file + system has moved, or, it may be the case that the target server is + functioning mainly, or solely, to refer clients to the servers on + which various file systems are located. + + o PUTROOTFH + + o LOOKUP "this" + + o LOOKUP "is" + + o LOOKUP "the" + + o LOOKUP "path" + o GETFH + + o GETATTR fsid,fileid,size,time_modify + + Under the given circumstances, the following will be the result. + + o PUTROOTFH --> NFS_OK. The current fh is now the root of the + pseudo-fs. + + o LOOKUP "this" --> NFS_OK. The current fh is for /this and is + within the pseudo-fs. + + o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is + within the pseudo-fs. + + o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and + is within the pseudo-fs. + + o LOOKUP "path" --> NFS_OK. The current fh is for /this/is/the/path + and is within a new, absent file system, but ... the client will + never see the value of that fh. + + o GETFH --> NFS4ERR_MOVED. Fails because current fh is in an absent + file system at the start of the operation and the spec makes no + exception for GETFH. + + o GETATTR fsid,fileid,size,time_modify. Not executed because the + failure of the GETFH stops processing of the COMPOUND. + + Given the failure of the GETFH, the client has the job of determining + the root of the absent file system and where to find that file + system, i.e. the server and path relative to that server's root fh. + Note here that in this example, the client did not obtain filehandles + and attribute information (e.g. fsid) for the intermediate + directories, so that it would not be sure where the absent file + system starts. It could be the case, for example, that /this/is/the + is the root of the moved file system and that the reason that the + lookup of "path" succeeded is that the file system was not absent on + that operation but was moved between the last LOOKUP and the GETFH + (since COMPOUND is not atomic). Even if we had the fsids for all of + the intermediate directories, we could have no way of knowing that + /this/is/the/path was the root of a new file system, since we don't + yet have its fsid. + + In order to get the necessary information, let us re-send the chain + of LOOKUPs with GETFHs and GETATTRs to at least get the fsids so we + can be sure where the appropriate file system boundaries are. The + client could choose to get fs_locations at the same time but in most + cases the client will have a good guess as to where file system + boundaries are (because of where and where not NFS4ERR_MOVED was + received) making fetching of fs_locations unnecessary. + + OP01: PUTROOTFH --> NFS_OK + + - Current fh is root of pseudo-fs. + + OP02: GETATTR(fsid) --> NFS_OK + + - Just for completeness. Normally, clients will know the fsid of + the pseudo-fs as soon as they establish communication with a + server. + + OP03: LOOKUP "this" --> NFS_OK + + OP04: GETATTR(fsid) --> NFS_OK + + - Get current fsid to see where file system boundaries are. The + fsid will be that for the pseudo-fs in this example, so no + boundary. + + OP05: GETFH --> NFS_OK + + - Current fh is for /this and is within pseudo-fs. + + OP06: LOOKUP "is" --> NFS_OK + + - Current fh is for /this/is and is within pseudo-fs. + + OP07: GETATTR(fsid) --> NFS_OK + + - Get current fsid to see where file system boundaries are. The + fsid will be that for the pseudo-fs in this example, so no + boundary. + + OP08: GETFH --> NFS_OK + + - Current fh is for /this/is and is within pseudo-fs. + + OP09: LOOKUP "the" --> NFS_OK + + - Current fh is for /this/is/the and is within pseudo-fs. + + OP10: GETATTR(fsid) --> NFS_OK + - Get current fsid to see where file system boundaries are. The + fsid will be that for the pseudo-fs in this example, so no + boundary. + + OP11: GETFH --> NFS_OK + + - Current fh is for /this/is/the and is within pseudo-fs. + + OP12: LOOKUP "path" --> NFS_OK + + - Current fh is for /this/is/the/path and is within a new, absent + file system, but ... + + - The client will never see the value of that fh + + OP13: GETATTR(fsid, fs_locations) --> NFS_OK + + - We are getting the fsid to know where the file system boundaries + are. In this operation the fsid will be different than that of + the parent directory (which in turn was retrieved in OP10). Note + that the fsid we are given will not necessarily be preserved at + the new location. That fsid might be different and in fact the + fsid we have for this file system might be a valid fsid of a + different file system on that new server. + + - In this particular case, we are pretty sure anyway that what has + moved is /this/is/the/path rather than /this/is/the since we have + the fsid of the latter and it is that of the pseudo-fs, which + presumably cannot move. However, in other examples, we might not + have this kind of information to rely on (e.g. /this/is/the might + be a non-pseudo file system separate from /this/is/the/path), so + we need to have another reliable source information on the + boundary of the file system which is moved. If, for example, the + file system "/this/is" had moved we would have a case of migration + rather than referral and once the boundaries of the migrated file + system was clear we could fetch fs_locations. + + - We are fetching fs_locations because the fact that we got an + NFS4ERR_MOVED at this point means that it most likely that this is + a referral and we need the destination. Even if it is the case + that "/this/is/the" is a file system which has migrated, we will + still need the location information for that file system. + + OP14: GETFH --> NFS4ERR_MOVED + - Fails because current fh is in an absent file system at the start + of the operation and the spec makes no exception for GETFH. Note + that this means the server will never send the client a filehandle + from within an absent file system. + + Given the above, the client knows where the root of the absent file + system is (/this/is/the/path), by noting where the change of fsid + occurred (between "the" and "path"). The fs_locations attribute also + gives the client the actual location of the absent file system, so + that the referral can proceed. The server gives the client the bare + minimum of information about the absent file system so that there + will be very little scope for problems of conflict between + information sent by the referring server and information of the file + system's home. No filehandles and very few attributes are present on + the referring server and the client can treat those it receives as + basically transient information with the function of enabling the + referral. + +7.8.2. Referral Example (READDIR) + + Another context in which a client may encounter referrals is when it + does a READDIR on directory in which some of the sub-directories are + the roots of absent file systems. + + Suppose such a directory is read as follows: + + o PUTROOTFH + + o LOOKUP "this" + + o LOOKUP "is" + + o LOOKUP "the" + + o READDIR (fsid, size, time_modify, mounted_on_fileid) + + In this case, because rdattr_error is not requested, fs_locations is + not requested, and some of attributes cannot be provided, the result + will be an NFS4ERR_MOVED error on the READDIR, with the detailed + results as follows: + + o PUTROOTFH --> NFS_OK. The current fh is at the root of the + pseudo-fs. + + o LOOKUP "this" --> NFS_OK. The current fh is for /this and is + within the pseudo-fs. + + o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is + within the pseudo-fs. + + o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and + is within the pseudo-fs. + + o READDIR (fsid, size, time_modify, mounted_on_fileid) --> + NFS4ERR_MOVED. Note that the same error would have been returned + if /this/is/the had migrated, when in fact it is because the + directory contains the root of an absent file system. + + So now suppose that we re-send with rdattr_error: + + o PUTROOTFH + + o LOOKUP "this" + + o LOOKUP "is" + + o LOOKUP "the" + + o READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid) + + The results will be: + + o PUTROOTFH --> NFS_OK. The current fh is at the root of the + pseudo-fs. + + o LOOKUP "this" --> NFS_OK. The current fh is for /this and is + within the pseudo-fs. + + o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is + within the pseudo-fs. + + o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and + is within the pseudo-fs. + + o READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid) + --> NFS_OK. The attributes for directory entry with the component + named "path" will only contain rdattr_error with the value + NFS4ERR_MOVED, together with an fsid value and a value for + mounted_on_fileid. + + So suppose we do another READDIR to get fs_locations (although we + could have used a GETATTR directly, as in Section 7.8.1). + + o PUTROOTFH + + o LOOKUP "this" + + o LOOKUP "is" + + o LOOKUP "the" + + o READDIR (rdattr_error, fs_locations, mounted_on_fileid, fsid, + size, time_modify) + + The results would be: + + o PUTROOTFH --> NFS_OK. The current fh is at the root of the + pseudo-fs. + + o LOOKUP "this" --> NFS_OK. The current fh is for /this and is + within the pseudo-fs. + + o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is + within the pseudo-fs. + + o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and + is within the pseudo-fs. + + o READDIR (rdattr_error, fs_locations, mounted_on_fileid, fsid, + size, time_modify) --> NFS_OK. The attributes will be as shown + below. + + The attributes for the directory entry with the component named + "path" will only contain + + o rdattr_error (value: NFS_OK) + + o fs_locations + + o mounted_on_fileid (value: unique fileid within referring file + system) + + o fsid (value: unique value within referring server) + + The attributes for entry "path" will not contain size or time_modify + because these attributes are not available within an absent file + system. + +7.9. The Attribute fs_locations + + The fs_locations attribute is structured in the following way: struct fs_location4 { - utf8str_cis server<>; + utf8val_must server<>; pathname4 rootpath; }; struct fs_locations4 { pathname4 fs_root; fs_location4 locations<>; }; - The fs_location struct is used to represent the location of a - filesystem by providing a server name and the path to the root of the - filesystem. For a multi-homed server or a set of servers that use - the same rootpath, an array of server names may be provided. An - entry in the server array is an UTF8 string and represents one of a - traditional DNS host name, IPv4 address, or IPv6 address. It is not - a requirement that all servers that share the same rootpath be listed - in one fs_location struct. The array of server names is provided for + The fs_location4 data type is used to represent the location of a + file system by providing a server name and the path to the root of + the file system within that server's namespace. When a set of + servers have corresponding file systems at the same path within their + namespaces, an array of server names may be provided. An entry in + the server array is a UTF-8 string and represents one of a + traditional DNS host name, IPv4 address, or IPv6 address, or an zero- + length string. A zero-length string SHOULD be used to indicate the + current address being used for the RPC call. It is not a requirement + that all servers that share the same rootpath be listed in one + fs_location4 instance. The array of server names is provided for convenience. Servers that share the same rootpath may also be listed - in separate fs_location entries in the fs_locations attribute. + in separate fs_location4 entries in the fs_locations attribute. - The fs_locations struct and attribute then contains an array of - locations. Since the name space of each server may be constructed - differently, the "fs_root" field is provided. The path represented - by fs_root represents the location of the filesystem in the server's - name space. Therefore, the fs_root path is only associated with the - server from which the fs_locations attribute was obtained. The - fs_root path is meant to aid the client in locating the filesystem at - the various servers listed. + The fs_locations4 data type and fs_locations attribute contain an + array of such locations. Since the namespace of each server may be + constructed differently, the "fs_root" field is provided. The path + represented by fs_root represents the location of the file system in + the current server's namespace, i.e. that of the server from which + the fs_locations attribute was obtained. The fs_root path is meant + to aid the client by clearly referencing the root of the file system + whose locations are being reported, no matter what object within the + current file system the current filehandle designates. The fs_root + is simply the pathname the client used to reach the object on the + current server, the object being that the fs_locations attribute + applies to. - As an example, there is a replicated filesystem located at two - servers (servA and servB). At servA the filesystem is located at - path "/a/b/c". At servB the filesystem is located at path "/x/y/z". - In this example the client accesses the filesystem first at servA - with a multi-component lookup path of "/a/b/c/d". Since the client - used a multi-component lookup to obtain the filehandle at "/a/b/c/d", - it is unaware that the filesystem's root is located in servA's name - space at "/a/b/c". When the client switches to servB, it will need - to determine that the directory it first referenced at servA is now - represented by the path "/x/y/z/d" on servB. To facilitate this, the - fs_locations attribute provided by servA would have a fs_root value - of "/a/b/c" and two entries in fs_location. One entry in fs_location - will be for itself (servA) and the other will be for servB with a - path of "/x/y/z". With this information, the client is able to - substitute "/x/y/z" for the "/a/b/c" at the beginning of its access - path and construct "/x/y/z/d" to use for the new server. + When the fs_locations attribute is interrogated and there are no + alternate file system locations, the server SHOULD return a zero- + length array of fs_location4 structures, together with a valid + fs_root. - See Section 16 "Security Considerations" for a discussion on the - recommendations for the security flavor to be used by any GETATTR - operation that requests the "fs_locations" attribute. + As an example, suppose there is a replicated file system located at + two servers (servA and servB). At servA, the file system is located + at path "/a/b/c". At, servB the file system is located at path + "/x/y/z". If the client were to obtain the fs_locations value for + the directory at "/a/b/c/d", it might not necessarily know that the + file system's root is located in servA's namespace at "/a/b/c". When + the client switches to servB, it will need to determine that the + directory it first referenced at servA is now represented by the path + "/x/y/z/d" on servB. To facilitate this, the fs_locations attribute + provided by servA would have a fs_root value of "/a/b/c" and two + entries in fs_locations. One entry in fs_locations will be for + itself (servA) and the other will be for servB with a path of + "/x/y/z". With this information, the client is able to substitute + "/x/y/z" for the "/a/b/c" at the beginning of its access path and + construct "/x/y/z/d" to use for the new server. -6.4. Filehandle Recovery for Migration or Replication + Note that: there is no requirement that the number of components in + each rootpath be the same; there is no relation between the number of + components in rootpath or fs_root; and the none of the components in + each rootpath and fs_root have to be the same. In the above example, + we could have had a third element in the locations array, with server + equal to "servC", and rootpath equal to "/I/II", and a fourth element + in locations with server equal to "servD", and rootpath equal to + "/aleph/beth/gimel/daleth/he". - Filehandles for filesystems that are replicated or migrated generally - have the same semantics as for filesystems that are not replicated or - migrated. For example, if a filesystem has persistent filehandles - and it is migrated to another server, the filehandle values for the - filesystem will be valid at the new server. + The relationship between fs_root to a rootpath is that the client + replaces the pathname indicated in fs_root for the current server for + the substitute indicated in rootpath for the new server. - For volatile filehandles, the servers involved likely do not have a - mechanism to transfer filehandle format and content between - themselves. Therefore, a server may have difficulty in determining - if a volatile filehandle from an old server should return an error of - NFS4ERR_FHEXPIRED. Therefore, the client is informed, with the use - of the fh_expire_type attribute, whether volatile filehandles will - expire at the migration or replication event. If the bit - FH4_VOL_MIGRATION is set in the fh_expire_type attribute, the client - must treat the volatile filehandle as if the server had returned the - NFS4ERR_FHEXPIRED error. At the migration or replication event in - the presence of the FH4_VOL_MIGRATION bit, the client will not - present the original or old volatile filehandle to the new server. - The client will start its communication with the new server by - recovering its filehandles using the saved file names. + For an example for a referred or migrated file system, suppose there + is a file system located at serv1. At serv1, the file system is + located at "/az/buky/vedi/glagoli". The client finds that object at + "glagoli" has migrated (or is a referral). The client gets the + fs_locations attribute, which contains an fs_root of "/az/buky/vedi/ + glagoli", and one element in the locations array, with server equal + to "serv2", and rootpath equal to "/izhitsa/fita". The client + replaces "/az/buky/vedi/glagoli" with "/izhitsa/fita", and uses the + latter pathname on "serv2". -7. NFS Server Name Space + Thus, the server MUST return an fs_root that is equal to the path the + client used to reach the object the fs_locations attribute applies + to. Otherwise the client cannot determine the new path to use on the + new server. -7.1. Server Exports +7.9.1. Inferring Transition Modes + + When fs_locations is used, information about the specific locations + should be assumed based on the following rules. + + The following rules are general and apply irrespective of the + context. + + o All listed file system instances should be considered as of the + same _handle_ class, if and only if, the current fh_expire_type + attribute does not include the FH4_VOL_MIGRATION bit. Note that + in the case of referral, filehandle issues do not apply since + there can be no filehandles known within the current file system + nor is there any access to the fh_expire_type attribute on the + referring (absent) file system. + + o All listed file system instances should be considered as of the + same _fileid_ class, if and only if, the fh_expire_type attribute + indicates persistent filehandles and does not include the + FH4_VOL_MIGRATION bit. Note that in the case of referral, fileid + issues do not apply since there can be no fileids known within the + referring (absent) file system nor is there any access to the + fh_expire_type attribute. + + o All file system instances servers should be considered as of + different _change_ classes. + + For other class assignments, handling of file system transitions + depends on the reasons for the transition: + + o When the transition is due to migration, that is the client was + directed to new file system after receiving an NFS4ERR_MOVED + error, the target should be treated as being of the same _write- + verifier_ class as the source. + + o When the transition is due to failover to another replica, that + is, the client selected another replica without receiving and + NFS4ERR_MOVED error, the target should be treated as being of a + different _write-verifier_ class from the source. + + The specific choices reflect typical implementation patterns for + failover and controlled migration respectively. + + See Section 17 for a discussion on the recommendations for the + security flavor to be used by any GETATTR operation that requests the + "fs_locations" attribute. + +8. NFS Server Name Space +8.1. Server Exports On a UNIX server the name space describes all the files reachable by pathnames under the root directory or "/". On a Windows NT server the name space constitutes all the files on disks named by mapped disk letters. NFS server administrators rarely make the entire server's filesystem name space available to NFS clients. More often portions of the name space are made available via an "export" feature. In previous versions of the NFS protocol, the root filehandle for each export is obtained through the MOUNT protocol; the client sends a string that identifies the export of name space and the server returns the root filehandle for it. The MOUNT protocol supports an EXPORTS procedure that will enumerate the server's exports. -7.2. Browsing Exports +8.2. Browsing Exports The NFS version 4 protocol provides a root filehandle that clients can use to obtain filehandles for these exports via a multi-component LOOKUP. A common user experience is to use a graphical user interface (perhaps a file "Open" dialog window) to find a file via progressive browsing through a directory tree. The client must be able to move from one export to another export via single-component, progressive LOOKUP operations. This style of browsing is not well supported by the NFS version 2 and @@ -2868,21 +4705,21 @@ An automounter on the client can obtain a snapshot of the server's name space using the EXPORTS procedure of the MOUNT protocol. If it understands the server's pathname syntax, it can create an image of the server's name space on the client. The parts of the name space that are not exported by the server are filled in with a "pseudo filesystem" that allows the user to browse from one mounted filesystem to another. There is a drawback to this representation of the server's name space on the client: it is static. If the server administrator adds a new export the client will be unaware of it. -7.3. Server Pseudo Filesystem +8.3. Server Pseudo Filesystem NFS version 4 servers avoid this name space inconsistency by presenting all the exports within the framework of a single server name space. An NFS version 4 client uses LOOKUP and READDIR operations to browse seamlessly from one export to another. Portions of the server name space that are not exported are bridged via a "pseudo filesystem" that provides a view of exported directories only. A pseudo filesystem has a unique fsid and behaves like a normal, read only filesystem. @@ -2886,62 +4723,63 @@ only. A pseudo filesystem has a unique fsid and behaves like a normal, read only filesystem. Based on the construction of the server's name space, it is possible that multiple pseudo filesystems may exist. For example, /a pseudo filesystem /a/b real filesystem /a/b/c pseudo filesystem /a/b/c/d real filesystem + Each of the pseudo filesystems are considered separate entities and therefore will have a unique fsid. -7.4. Multiple Roots +8.4. Multiple Roots The DOS and Windows operating environments are sometimes described as having "multiple roots". Filesystems are commonly represented as disk letters. MacOS represents filesystems as top level names. NFS version 4 servers for these platforms can construct a pseudo file system above these root names so that disk letters or volume names are simply directory names in the pseudo root. -7.5. Filehandle Volatility +8.5. Filehandle Volatility The nature of the server's pseudo filesystem is that it is a logical representation of filesystem(s) available from the server. Therefore, the pseudo filesystem is most likely constructed dynamically when the server is first instantiated. It is expected that the pseudo filesystem may not have an on disk counterpart from which persistent filehandles could be constructed. Even though it is preferable that the server provide persistent filehandles for the pseudo filesystem, the NFS client should expect that pseudo file system filehandles are volatile. This can be confirmed by checking the associated "fh_expire_type" attribute for those filehandles in question. If the filehandles are volatile, the NFS client must be prepared to recover a filehandle value (e.g., with a multi-component LOOKUP) when receiving an error of NFS4ERR_FHEXPIRED. -7.6. Exported Root +8.6. Exported Root If the server's root filesystem is exported, one might conclude that a pseudo-filesystem is not needed. This would be wrong. Assume the following filesystems on a server: / disk1 (exported) /a disk2 (not exported) /a/b disk3 (exported) Because disk2 is not exported, disk3 cannot be reached with simple LOOKUPs. The server must bridge the gap with a pseudo-filesystem. -7.7. Mount Point Crossing +8.7. Mount Point Crossing The server filesystem environment may be constructed in such a way that one filesystem contains a directory which is 'covered' or mounted upon by a second filesystem. For example: /a/b (filesystem 1) /a/b/c/d (filesystem 2) The pseudo filesystem for this server may be constructed to look like: @@ -2953,21 +4791,21 @@ It is the server's responsibility to present the pseudo filesystem that is complete to the client. If the client sends a lookup request for the path "/a/b/c/d", the server's response is the filehandle of the filesystem "/a/b/c/d". In previous versions of the NFS protocol, the server would respond with the filehandle of directory "/a/b/c/d" within the filesystem "/a/b". The NFS client will be able to determine if it crosses a server mount point by a change in the value of the "fsid" attribute. -7.8. Security Policy and Name Space Presentation +8.8. Security Policy and Name Space Presentation The application of the server's security policy needs to be carefully considered by the implementor. One may choose to limit the viewability of portions of the pseudo filesystem based on the server's perception of the client's ability to authenticate itself properly. However, with the support of multiple security mechanisms and the ability to negotiate the appropriate use of these mechanisms, the server is unable to properly determine if a client will be able to authenticate itself. If, based on its policies, the server chooses to limit the contents of the pseudo filesystem, the server @@ -2986,26 +4824,26 @@ The security policy for /a/b/c is Kerberos with integrity. The server should apply the same security policy to /, /a, and /a/b. This allows for the extension of the protection of the server's namespace to the ancestors of the real shared resource. For the case of the use of multiple, disjoint security mechanisms in the server's resources, the security for a particular object in the server's namespace should be the union of all security mechanisms of all direct descendants. -8. File Locking and Share Reservations +9. File Locking and Share Reservations Integrating locking into the NFS protocol necessarily causes it to be stateful. With the inclusion of share reservations the protocol becomes substantially more dependent on state than the traditional - combination of NFS and NLM [26]. There are three components to + combination of NFS and NLM [28]. There are three components to making this state manageable: o Clear division between client and server o Ability to reliably detect inconsistency in state between client and server o Simple and robust recovery mechanisms In this model, the server owns the state information. The client @@ -3020,51 +4858,51 @@ protocol mechanisms used when a file is opened or created (LOOKUP, CREATE, ACCESS) need to be replaced. The NFS version 4 protocol has an OPEN operation that subsumes the NFS version 3 methodology of LOOKUP, CREATE, and ACCESS. However, because many operations require a filehandle, the traditional LOOKUP is preserved to map a file name to filehandle without establishing state on the server. The policy of granting access or modifying files is managed by the server based on the client's state. These mechanisms can implement policy ranging from advisory only locking to full mandatory locking. -8.1. Locking +9.1. Locking It is assumed that manipulating a lock is rare when compared to READ and WRITE operations. It is also assumed that crashes and network partitions are relatively rare. Therefore it is important that the READ and WRITE operations have a lightweight mechanism to indicate if they possess a held lock. A lock request contains the heavyweight information required to establish a lock and uniquely define the lock owner. The following sections describe the transition from the heavy weight information to the eventual stateid used for most client and server locking and lease interactions. -8.1.1. Client ID +9.1.1. Client ID For each LOCK request, the client must identify itself to the server. This is done in such a way as to allow for correct lock identification and crash recovery. A sequence of a SETCLIENTID operation followed by a SETCLIENTID_CONFIRM operation is required to establish the identification onto the server. Establishment of identification by a new incarnation of the client also has the effect of immediately breaking any leased state that a previous incarnation of the client might have had on the server, as opposed to forcing the new client incarnation to wait for the leases to expire. Breaking the lease state amounts to the server removing all lock, share reservation, and, where the server is not supporting the CLAIM_DELEGATE_PREV claim type, all delegation state associated with same client with the same identity. For discussion of delegation - state recovery, see Section 9.2.1 "Delegation Recovery". + state recovery, see Section 10.2.1. Client identification is encapsulated in the following structure: struct SETCLIENTID4args { nfs_client_id4 client; cb_client4 callback; uint32_t callback_ident; }; The first field, verifier is a client incarnation verifier that is @@ -3160,32 +4998,32 @@ clientid4, instead of the longer and less compact nfs_client_id4 structure. This shorthand client identifier (a clientid) is assigned by the server and should be chosen so that it will not conflict with a clientid previously assigned by the server. This applies across server restarts or reboots. When a clientid is presented to a server and that clientid is not recognized, as would happen after a server reboot, the server will reject the request with the error NFS4ERR_STALE_CLIENTID. When this happens, the client must obtain a new clientid by use of the SETCLIENTID operation and then proceed to any other necessary recovery for the server reboot case (See - Section 8.6.2 "Server Failure and Recovery"). + Section 9.6.2). The client must also employ the SETCLIENTID operation when it receives a NFS4ERR_STALE_STATEID error using a stateid derived from its current clientid, since this also indicates a server reboot which - has invalidated the existing clientid (see Section 8.1.3 "lock_owner - and stateid Definition" for details). + has invalidated the existing clientid (see Section 9.1.3 for + details). See the detailed descriptions of SETCLIENTID and SETCLIENTID_CONFIRM for a complete specification of the operations. -8.1.2. Server Release of Clientid +9.1.2. Server Release of Clientid If the server determines that the client holds no associated state for its clientid, the server may choose to release the clientid. The server may make this choice for an inactive client so that resources are not consumed by those intermittently active clients. If the client contacts the server after this release, the server must ensure the client receives the appropriate error so that it will use the SETCLIENTID/SETCLIENTID_CONFIRM sequence to establish a new identity. It should be clear that the server must be very hesitant to release a clientid since the resulting work on the client to recover from such @@ -3204,21 +5042,21 @@ that changes security flavors, and under the new flavor, there is no mapping to the previous owner) will in rare cases result in NFS4ERR_CLID_INUSE. In that event, when the server gets a SETCLIENTID for a client id that currently has no state, or it has state, but the lease has expired, rather than returning NFS4ERR_CLID_INUSE, the server MUST allow the SETCLIENTID, and confirm the new clientid if followed by the appropriate SETCLIENTID_CONFIRM. -8.1.3. lock_owner and stateid Definition +9.1.3. lock_owner and stateid Definition When requesting a lock, the client must present to the server the clientid and an identifier for the owner of the requested lock. These two fields are referred to as the lock_owner and the definition of those fields are: o A clientid returned by the server as part of the client's use of the SETCLIENTID operation. o A variable length opaque array used to uniquely define the owner @@ -3276,21 +5113,21 @@ o utilize the "seqid" field of each stateid, such that seqid is monotonically incremented for each stateid that is associated with the same index into the locking-state table. By matching the incoming stateid and its field values with the state held at the server, the server is able to easily determine if a stateid is valid for its current instantiation and state. If the stateid is not valid, the appropriate error can be supplied to the client. -8.1.4. Use of the stateid and Locking +9.1.4. Use of the stateid and Locking All READ, WRITE and SETATTR operations contain a stateid. For the purposes of this section, SETATTR operations which change the size attribute of a file are treated as if they are writing the area between the old and new size (i.e., the range truncated or added to the file by means of the SETATTR), even where SETATTR is not explicitly mentioned in the text. If the lock_owner performs a READ or WRITE in a situation in which it has established a lock or share reservation on the server (any OPEN @@ -3382,21 +5219,21 @@ A lock may not be granted while a READ or WRITE operation using one of the special stateids is being performed and the range of the lock request conflicts with the range of the READ or WRITE operation. For the purposes of this paragraph, a conflict occurs when a shared lock is requested and a WRITE operation is being performed, or an exclusive lock is requested and either a READ or a WRITE operation is being performed. A SETATTR that sets size is treated similarly to a WRITE as discussed above. -8.1.5. Sequencing of Lock Requests +9.1.5. Sequencing of Lock Requests Locking is different than most NFS operations as it requires "at- most-one" semantics that are not provided by ONCRPC. ONCRPC over a reliable transport is not sufficient because a sequence of locking requests may span multiple TCP connections. In the face of retransmission or reordering, lock or unlock requests must have a well defined and consistent behavior. To accomplish this, each lock request contains a sequence number that is a consecutively increasing integer. Different lock_owners have different sequences. The server maintains the last sequence number (L) received and the response that @@ -3412,87 +5249,87 @@ received before the last request (L) was sent. If a duplicate of last request (r == L) is received, the stored response is returned. If a request beyond the next sequence (r == L + 2) is received, it is rejected with the return of error NFS4ERR_BAD_SEQID. Sequence history is reinitialized whenever the SETCLIENTID/SETCLIENTID_CONFIRM sequence changes the client verifier. Since the sequence number is represented with an unsigned 32-bit integer, the arithmetic involved with the sequence number is mod 2^32. For an example of modulo arithmetic involving sequence numbers - see [27]. + see [29]. It is critical the server maintain the last response sent to the client to provide a more reliable cache of duplicate non-idempotent - requests than that of the traditional cache described in [28]. The + requests than that of the traditional cache described in [30]. The traditional duplicate request cache uses a least recently used algorithm for removing unneeded requests. However, the last lock request and response on a given lock_owner must be cached as long as the lock state exists on the server. The client MUST monotonically increment the sequence number for the CLOSE, LOCK, LOCKU, OPEN, OPEN_CONFIRM, and OPEN_DOWNGRADE operations. This is true even in the event that the previous operation that used the sequence number received an error. The only exception to this rule is if the previous operation received one of the following errors: NFS4ERR_STALE_CLIENTID, NFS4ERR_STALE_STATEID, NFS4ERR_BAD_STATEID, NFS4ERR_BAD_SEQID, NFS4ERR_BADXDR, NFS4ERR_RESOURCE, NFS4ERR_NOFILEHANDLE. -8.1.6. Recovery from Replayed Requests +9.1.6. Recovery from Replayed Requests As described above, the sequence number is per lock_owner. As long as the server maintains the last sequence number received and follows the methods described above, there are no risks of a Byzantine router re-sending old requests. The server need only maintain the (lock_owner, sequence number) state as long as there are open files or closed files with locks outstanding. LOCK, LOCKU, OPEN, OPEN_DOWNGRADE, and CLOSE each contain a sequence number and therefore the risk of the replay of these operations resulting in undesired effects is non-existent while the server maintains the lock_owner state. -8.1.7. Releasing lock_owner State +9.1.7. Releasing lock_owner State When a particular lock_owner no longer holds open or file locking state at the server, the server may choose to release the sequence number state associated with the lock_owner. The server may make this choice based on lease expiration, for the reclamation of server memory, or other implementation specific details. In any event, the server is able to do this safely only when the lock_owner no longer is being utilized by the client. The server may choose to hold the lock_owner state in the event that retransmitted requests are received. However, the period to hold this state is implementation specific. In the case that a LOCK, LOCKU, OPEN_DOWNGRADE, or CLOSE is retransmitted after the server has previously released the lock_owner state, the server will find that the lock_owner has no files open and an error will be returned to the client. If the lock_owner does have a file open, the stateid will not match and again an error is returned to the client. -8.1.8. Use of Open Confirmation +9.1.8. Use of Open Confirmation In the case that an OPEN is retransmitted and the lock_owner is being used for the first time or the lock_owner state has been previously released by the server, the use of the OPEN_CONFIRM operation will prevent incorrect behavior. When the server observes the use of the lock_owner for the first time, it will direct the client to perform the OPEN_CONFIRM for the corresponding OPEN. This sequence establishes the use of an lock_owner and associated sequence number. Since the OPEN_CONFIRM sequence connects a new open_owner on the server with an existing open_owner on a client, the sequence number may have any value. The OPEN_CONFIRM step assures the server that - the value received is the correct one. See Section 14.20 - "OPEN_CONFIRM - Confirm Open" for further details. + the value received is the correct one. (see Section 15.20 for further + details.) There are a number of situations in which the requirement to confirm an OPEN would pose difficulties for the client and server, in that they would be prevented from acting in a timely fashion on information received, because that information would be provisional, subject to deletion upon non-confirmation. Fortunately, these are situations in which the server can avoid the need for confirmation when responding to open requests. The two constraints are: o The server must not bestow a delegation for any open which would @@ -3518,65 +5355,65 @@ Requiring open confirmation on reclaim-type opens is avoidable because of the nature of the environments in which such opens are done. For CLAIM_PREVIOUS opens, this is immediately after server reboot, so there should be no time for lockowners to be created, found to be unused, and recycled. For CLAIM_DELEGATE_PREV opens, we are dealing with a client reboot situation. A server which supports delegation can be sure that no lockowners for that client have been recycled since client initialization and thus can ensure that confirmation will not be required. -8.2. Lock Ranges +9.2. Lock Ranges The protocol allows a lock owner to request a lock with a byte range and then either upgrade or unlock a sub-range of the initial lock. It is expected that this will be an uncommon type of request. In any case, servers or server filesystems may not be able to support sub- range lock semantics. In the event that a server receives a locking request that represents a sub-range of current locking state for the lock owner, the server is allowed to return the error NFS4ERR_LOCK_RANGE to signify that it does not support sub-range lock operations. Therefore, the client should be prepared to receive this error and, if appropriate, report the error to the requesting application. The client is discouraged from combining multiple independent locking ranges that happen to be adjacent into a single request since the server may not support sub-range requests and for reasons related to the recovery of file locking state in the event of server failure. - As discussed in the section "Server Failure and Recovery" below, the - server may employ certain optimizations during recovery that work - effectively only when the client's behavior during lock recovery is - similar to the client's locking behavior prior to server failure. + As discussed in the Section 9.6.2 below, the server may employ + certain optimizations during recovery that work effectively only when + the client's behavior during lock recovery is similar to the client's + locking behavior prior to server failure. -8.3. Upgrading and Downgrading Locks +9.3. Upgrading and Downgrading Locks If a client has a write lock on a record, it can request an atomic downgrade of the lock to a read lock via the LOCK request, by setting the type to READ_LT. If the server supports atomic downgrade, the request will succeed. If not, it will return NFS4ERR_LOCK_NOTSUPP. The client should be prepared to receive this error, and if appropriate, report the error to the requesting application. If a client has a read lock on a record, it can request an atomic upgrade of the lock to a write lock via the LOCK request by setting the type to WRITE_LT or WRITEW_LT. If the server does not support atomic upgrade, it will return NFS4ERR_LOCK_NOTSUPP. If the upgrade can be achieved without an existing conflict, the request will succeed. Otherwise, the server will return either NFS4ERR_DENIED or NFS4ERR_DEADLOCK. The error NFS4ERR_DEADLOCK is returned if the client issued the LOCK request with the type set to WRITEW_LT and the server has detected a deadlock. The client should be prepared to receive such errors and if appropriate, report the error to the requesting application. -8.4. Blocking Locks +9.4. Blocking Locks Some clients require the support of blocking locks. The NFS version 4 protocol must not rely on a callback mechanism and therefore is unable to notify a client when a previously denied lock has been granted. Clients have no choice but to continually poll for the lock. This presents a fairness problem. Two new lock types are added, READW and WRITEW, and are used to indicate to the server that the client is requesting a blocking lock. The server should maintain an ordered list of pending blocking locks. When the conflicting lock is released, the server may wait the lease period for the first @@ -3590,21 +5427,21 @@ storage would be required to guarantee ordered granting of blocking locks. Servers may also note the lock types and delay returning denial of the request to allow extra time for a conflicting lock to be released, allowing a successful return. In this way, clients can avoid the burden of needlessly frequent polling for blocking locks. The server should take care in the length of delay in the event the client retransmits the request. -8.5. Lease Renewal +9.5. Lease Renewal The purpose of a lease is to allow a server to remove stale locks that are held by a client that has crashed or is otherwise unreachable. It is not a mechanism for cache consistency and lease renewals may not be denied if the lease interval has not expired. The following events cause implicit renewal of all of the leases for a given client (i.e., all those sharing a given clientid). Each of these is a positive indication that the client is still active and that the associated state held at the server, for the client, is @@ -3634,31 +5471,31 @@ renewal and in the worst case one RPC is required every lease period (i.e., a RENEW operation). The number of locks held by the client is not a factor since all state for the client is involved with the lease renewal action. Since all operations that create a new lease also renew existing leases, the server must maintain a common lease expiration time for all valid leases for a given client. This lease time can then be easily updated upon implicit lease renewal actions. -8.6. Crash Recovery +9.6. Crash Recovery The important requirement in crash recovery is that both the client and the server know when the other has failed. Additionally, it is required that a client sees a consistent view of data across server restarts or reboots. All READ and WRITE operations that may have been queued within the client or network buffers must wait until the client has successfully recovered the locks protecting the READ and WRITE operations. -8.6.1. Client Failure and Recovery +9.6.1. Client Failure and Recovery In the event that a client fails, the server may recover the client's locks when the associated leases have expired. Conflicting locks from another client may only be granted after this lease expiration. If the client is able to restart or reinitialize within the lease period the client may be forced to wait the remainder of the lease period before obtaining new locks. To minimize client delay upon restart, lock requests are associated with an instance of the client by a client supplied verifier. This @@ -3674,39 +5511,39 @@ initialization, the server can compare a new verifier to the verifier associated with currently held locks and determine that they do not match. This signifies the client's new instantiation and subsequent loss of locking state. As a result, the server is free to release all locks held which are associated with the old clientid which was derived from the old verifier. Note that the verifier must have the same uniqueness properties of the verifier for the COMMIT operation. -8.6.2. Server Failure and Recovery +9.6.2. Server Failure and Recovery If the server loses locking state (usually as a result of a restart or reboot), it must allow clients time to discover this fact and re- establish the lost locking state. The client must be able to re- establish the locking state without having the server deny valid requests because the server has granted conflicting access to another client. Likewise, if there is the possibility that clients have not yet re-established their locking state for a file, the server must disallow READ and WRITE operations for that file. The duration of this recovery period is equal to the duration of the lease period. A client can determine that server failure (and thus loss of locking state) has occurred, when it receives one of two errors. The NFS4ERR_STALE_STATEID error indicates a stateid invalidated by a reboot or restart. The NFS4ERR_STALE_CLIENTID error indicates a clientid invalidated by reboot or restart. When either of these are - received, the client must establish a new clientid (See Section 8.1.1 - "Client ID") and re-establish the locking state as discussed below. + received, the client must establish a new clientid (see + Section 9.1.1) and re-establish the locking state as discussed below. The period of special handling of locking and READs and WRITEs, equal in duration to the lease period, is referred to as the "grace period". During the grace period, clients recover locks and the associated state by reclaim-type locking requests (i.e., LOCK requests with reclaim set to true and OPEN operations with a claim type of CLAIM_PREVIOUS). During the grace period, the server must reject READ and WRITE operations and non-reclaim locking requests (i.e., other LOCK and OPEN operations) with an error of NFS4ERR_GRACE. @@ -3743,38 +5580,38 @@ requests to be processed during the grace period, it MUST determine that no lock subsequently reclaimed will be rejected and that no lock subsequently reclaimed would have prevented any I/O operation processed during the grace period. Clients should be prepared for the return of NFS4ERR_GRACE errors for non-reclaim lock and I/O requests. In this case the client should employ a retry mechanism for the request. A delay (on the order of several seconds) between retries should be used to avoid overwhelming the server. Further discussion of the general issue is included in - [19]. The client must account for the server that is able to perform + [20]. The client must account for the server that is able to perform I/O and non-reclaim locking requests within the grace period as well as those that can not do so. A reclaim-type locking request outside the server's grace period can only succeed if the server can guarantee that no conflicting lock or I/O request has been granted since reboot or restart. A server may, upon restart, establish a new value for the lease period. Therefore, clients should, once a new clientid is established, refetch the lease_time attribute and use it as the basis for lease renewal for the lease associated with that server. However, the server must establish, for this restart event, a grace period at least as long as the lease period for the previous server instantiation. This allows the client state obtained during the previous server instance to be reliably re-established. -8.6.3. Network Partitions and Recovery +9.6.3. Network Partitions and Recovery If the duration of a network partition is greater than the lease period provided by the server, the server will have not received a lease renewal from the client. If this occurs, the server may free all locks held for the client. As a result, all stateids held by the client will become invalid or stale. Once the client is able to reach the server after such a network partition, all I/O submitted by the client with the now invalid stateids will fail with the server returning the error NFS4ERR_EXPIRED. Once this error is received, the client will suitably notify the application that held the lock. @@ -3863,23 +5700,22 @@ lockowner's sequence. For the two aforementioned edge conditions, the harshest a server can be, and still support a grace period for reclaims, requires that the server record in stable storage information some minimal information. For example, a server implementation could, for each client, save in stable storage a record containing: o the client's id string o a boolean that indicates if the client's lease expired or if there - was administrative intervention (see the section, Server - Revocation of Locks) to revoke a record lock, share reservation, - or delegation + was administrative intervention (see Section 9.8) to revoke a + record lock, share reservation, or delegation o a timestamp that is updated the first time after a server boot or reboot the client acquires record locking, share reservation, or delegation state on the server. The timestamp need not be updated on subsequent lock requests until the server reboots. The server implementation would also record in the stable storage the timestamps from the two most recent server reboots. Assuming the above record keeping, for the first edge condition, @@ -3918,28 +5754,26 @@ When the client receives NFS4ERR_NO_GRACE, it could examine the change attribute of the objects the client is trying to reclaim state for, and use that to determine whether to re-establish the state via normal OPEN or LOCK requests. This is acceptable provided the client's operating environment allows it. In otherwords, the client implementor is advised to document for his users the behavior. The client could also inform the application that its record lock or share reservations (whether they were delegated or not) have been lost, such as via a UNIX signal, a GUI pop-up window, etc. See - Section 9.5, "Data Caching and Revocation" for a discussion of what - the client should do for dealing with unreclaimed delegations on - client state. + Section 10.5, for a discussion of what the client should do for + dealing with unreclaimed delegations on client state. - For further discussion of revocation of locks see Section 8.8 "Server - Revocation of Locks". + For further discussion of revocation of locks see Section 9.8. -8.7. Recovery from a Lock Request Timeout or Abort +9.7. Recovery from a Lock Request Timeout or Abort In the event a lock request times out, a client may decide to not retry the request. The client may also abort the request when the process for which it was issued is terminated (e.g., in UNIX due to a signal). It is possible though that the server received the request and acted upon it. This would change the state on the server without the client being aware of the change. It is paramount that the client re-synchronize state with server before it attempts any other operation that takes a seqid and/or a stateid with the same lock_owner. This is straightforward to do without a special re- @@ -3951,21 +5785,21 @@ not receive a response. From this, the next time the client does a lock operation for the lock_owner, it can send the cached request, if there is one, and if the request was one that established state (e.g., a LOCK or OPEN operation), the server will return the cached result or if never saw the request, perform it. The client can follow up with a request to remove the state (e.g., a LOCKU or CLOSE operation). With this approach, the sequencing and stateid information on the client and server for the given lock_owner will re-synchronize and in turn the lock state will re-synchronize. -8.8. Server Revocation of Locks +9.8. Server Revocation of Locks At any point, the server can revoke locks held by a client and the client must be prepared for this event. When the client detects that its locks have been or may have been revoked, the client is responsible for validating the state information between itself and the server. Validating locking state for the client means that it must verify or reclaim state for each lock currently held. The first instance of lock revocation is upon server reboot or re- initialization. In this instance the client will receive an error @@ -3993,36 +5827,36 @@ by the client. As a result of revocation, the client will receive an error of NFS4ERR_ADMIN_REVOKED. In this instance the client may assume that only the lock_owner's locks have been lost. The client notifies the lock holder appropriately. The client may not assume the lease period has been renewed as a result of a failed operation. When the client determines the lease period may have expired, the client must mark all locks held for the associated lease as "unvalidated". This means the client has been unable to re-establish or confirm the appropriate lock state with the server. As described - in the previous section on crash recovery, there are scenarios in - which the server may grant conflicting locks after the lease period - has expired for a client. When it is possible that the lease period - has expired, the client must validate each lock currently held to - ensure that a conflicting lock has not been granted. The client may - accomplish this task by issuing an I/O request, either a pending I/O - or a zero-length read, specifying the stateid associated with the - lock in question. If the response to the request is success, the - client has validated all of the locks governed by that stateid and - re-established the appropriate state between itself and the server. + in Section 9.6, there are scenarios in which the server may grant + conflicting locks after the lease period has expired for a client. + When it is possible that the lease period has expired, the client + must validate each lock currently held to ensure that a conflicting + lock has not been granted. The client may accomplish this task by + issuing an I/O request, either a pending I/O or a zero-length read, + specifying the stateid associated with the lock in question. If the + response to the request is success, the client has validated all of + the locks governed by that stateid and re-established the appropriate + state between itself and the server. If the I/O request is not successful, then one or more of the locks associated with the stateid was revoked by the server and the client must notify the owner. -8.9. Share Reservations +9.9. Share Reservations A share reservation is a mechanism to control access to a file. It is a separate and independent mechanism from record locking. When a client opens a file, it issues an OPEN operation to the server specifying the type of access required (READ, WRITE, or BOTH) and the type of access to deny others (deny NONE, READ, WRITE, or BOTH). If the OPEN fails the client will fail the application's open request. Pseudo-code definition of the semantics: @@ -4040,21 +5874,21 @@ const OPEN4_SHARE_ACCESS_READ = 0x00000001; const OPEN4_SHARE_ACCESS_WRITE = 0x00000002; const OPEN4_SHARE_ACCESS_BOTH = 0x00000003; const OPEN4_SHARE_DENY_NONE = 0x00000000; const OPEN4_SHARE_DENY_READ = 0x00000001; const OPEN4_SHARE_DENY_WRITE = 0x00000002; const OPEN4_SHARE_DENY_BOTH = 0x00000003; -8.10. OPEN/CLOSE Operations +9.10. OPEN/CLOSE Operations To provide correct share semantics, a client MUST use the OPEN operation to obtain the initial filehandle and indicate the desired access and what if any access to deny. Even if the client intends to use a stateid of all 0's or all 1's, it must still obtain the filehandle for the regular file with the OPEN operation so the appropriate share semantics can be applied. For clients that do not have a deny mode built into their open programming interfaces, deny equal to NONE should be used. @@ -4070,21 +5904,21 @@ failure, NFS4ERR_LOCKS_HELD, if any locks would exist after the CLOSE. The LOOKUP operation will return a filehandle without establishing any lock state on the server. Without a valid stateid, the server will assume the client has the least access. For example, a file opened with deny READ/WRITE cannot be accessed using a filehandle obtained through LOOKUP because it would not have a valid stateid (i.e., using a stateid of all bits 0 or all bits 1). -8.10.1. Close and Retention of State Information +9.10.1. Close and Retention of State Information Since a CLOSE operation requests deallocation of a stateid, dealing with retransmission of the CLOSE, may pose special difficulties, since the state information, which normally would be used to determine the state of the open file being designated, might be deallocated, resulting in an NFS4ERR_BAD_STATEID error. Servers may deal with this problem in a number of ways. To provide the greatest degree assurance that the protocol is being used properly, a server should, rather than deallocate the stateid, mark @@ -4106,21 +5940,21 @@ Servers may avoid this complexity, at the cost of less complete protocol error checking, by simply responding NFS4_OK in the event of a CLOSE for a deallocated stateid, on the assumption that this case must be caused by a retransmitted close. When adopting this approach, it is desirable to at least log an error when returning a no-error indication in this situation. If the server maintains a reply-cache mechanism, it can verify the CLOSE is indeed a retransmission and avoid error logging in most cases. -8.11. Open Upgrade and Downgrade +9.11. Open Upgrade and Downgrade When an OPEN is done for a file and the lockowner for which the open is being done already has the file open, the result is to upgrade the open file status maintained on the server to include the access and deny bits specified by the new OPEN as well as those for the existing OPEN. The result is that there is one open file, as far as the protocol is concerned, and it includes the union of the access and deny bits for all of the OPEN requests completed. Only a single CLOSE will be done to reset the effects of both OPENs. Note that the client, when issuing the OPEN, may not know that the same file is in @@ -4137,40 +5971,40 @@ When multiple open files on the client are merged into a single open file object on the server, the close of one of the open files (on the client) may necessitate change of the access and deny status of the open file on the server. This is because the union of the access and deny bits for the remaining opens may be smaller (i.e., a proper subset) than previously. The OPEN_DOWNGRADE operation is used to make the necessary change and the client should use it to update the server so that share reservation requests by other clients are handled properly. -8.12. Short and Long Leases +9.12. Short and Long Leases When determining the time period for the server lease, the usual lease tradeoffs apply. Short leases are good for fast server recovery at a cost of increased RENEW or READ (with zero length) requests. Longer leases are certainly kinder and gentler to servers trying to handle very large numbers of clients. The number of RENEW requests drop in proportion to the lease time. The disadvantages of long leases are slower recovery after server failure (the server must wait for the leases to expire and the grace period to elapse before granting new lock requests) and increased file contention (if client fails to transmit an unlock request then server must wait for lease expiration before granting new locks). Long leases are usable if the server is able to store lease state in non-volatile memory. Upon recovery, the server can reconstruct the lease state from its non-volatile memory and continue operation with its clients and therefore long leases would not be an issue. -8.13. Clocks, Propagation Delay, and Calculating Lease Expiration +9.13. Clocks, Propagation Delay, and Calculating Lease Expiration To avoid the need for synchronized clocks, lease times are granted by the server as a time delta. However, there is a requirement that the client and server clocks do not drift excessively over the duration of the lock. There is also the issue of propagation delay across the network which could easily be several hundred milliseconds as well as the possibility that requests will be lost and need to be retransmitted. To take propagation delay into account, the client should subtract it @@ -4182,43 +6016,42 @@ before the lease would expire. The server's lease period configuration should take into account the network distance of the clients that will be accessing the server's resources. It is expected that the lease period will take into account the network propagation delays and other network delay factors for the client population. Since the protocol does not allow for an automatic method to determine an appropriate lease period, the server's administrator may have to tune the lease period. -8.14. Migration, Replication and State +9.14. Migration, Replication and State When responsibility for handling a given file system is transferred to a new server (migration) or the client chooses to use an alternate server (e.g., in response to server unresponsiveness) in the context of file system replication, the appropriate handling of state shared between the client and server (i.e., locks, leases, stateids, and clientids) is as described below. The handling differs between migration and replication. For related discussion of file server - state and recover of such see the sections under "File Locking and - Share Reservations". + state and recover of such see the sections under Section 9.6. If server replica or a server immigrating a filesystem agrees to, or is expected to, accept opaque values from the client that originated from another server, then it is a wise implementation practice for the servers to encode the "opaque" values in network byte order. This way, servers acting as replicas or immigrating filesystems will be able to parse values like stateids, directory cookies, filehandles, etc. even if their native byte order is different from other servers cooperating in the replication and migration of the filesystem. -8.14.1. Migration and State +9.14.1. Migration and State In the case of migration, the servers involved in the migration of a filesystem SHOULD transfer all server state from the original to the new server. This must be done in a way that is transparent to the client. This state transfer will ease the client's transition when a filesystem migration occurs. If the servers are successful in transferring all state, the client will continue to use stateids assigned by the original server. Therefore the new server must recognize these stateids as valid. This holds true for the clientid as well. Since responsibility for an entire filesystem is @@ -4242,42 +6075,42 @@ in a RENEW op or a READ op of zero length), the client must be prepared to receive either NFS4ERR_STALE_CLIENTID or NFS4ERR_STALE_STATEID from the new server. The client should then recover its state information as it normally would in response to a server failure. The new server must take care to allow for the recovery of state information as it would in the event of server restart. A client SHOULD re-establish new callback information with the new server as soon as possible, according to sequences described in - sections Section 14.35 and Section 14.36. This ensures that server - operations are not blocked by the inability to recall delegations. + Section 15.35 and Section 15.36. This ensures that server operations + are not blocked by the inability to recall delegations. -8.14.2. Replication and State +9.14.2. Replication and State Since client switch-over in the case of replication is not under server control, the handling of state is different. In this case, leases, stateids and clientids do not have validity across a transition from one server to another. The client must re-establish its locks on the new server. This can be compared to the re- establishment of locks by means of reclaim-type requests after a server reboot. The difference is that the server has no provision to distinguish requests reclaiming locks from those obtaining new locks or to defer the latter. Thus, a client re-establishing a lock on the new server (by means of a LOCK or OPEN request), may have the requests denied due to a conflicting lock. Since replication is intended for read-only use of filesystems, such denial of locks should not pose large difficulties in practice. When an attempt to re-establish a lock on a new server is denied, the client should treat the situation as if his original lock had been revoked. -8.14.3. Notification of Migrated Lease +9.14.3. Notification of Migrated Lease In the case of lease renewal, the client may not be submitting requests for a filesystem that has been migrated to another server. This can occur because of the implicit lease renewal mechanism. The client renews leases for all filesystems when submitting a request to any one filesystem at the server. In order for the client to schedule renewal of leases that may have been relocated to the new server, the client must find out about lease relocation before those leases expire. To accomplish this, all @@ -4293,21 +6126,21 @@ perform an operation on each filesystem associated with the server in question. When the client receives an NFS4ERR_MOVED error, the client can follow the normal process to obtain the new server information (through the fs_locations attribute) and perform renewal of those leases on the new server. If the server has not had state transferred to it transparently, the client will receive either NFS4ERR_STALE_CLIENTID or NFS4ERR_STALE_STATEID from the new server, as described above, and the client can then recover state information as it does in the event of server failure. -8.14.4. Migration and the Lease_time Attribute +9.14.4. Migration and the Lease_time Attribute In order that the client may appropriately manage its leases in the case of migration, the destination server must establish proper values for the lease_time attribute. When state is transferred transparently, that state should include the correct value of the lease_time attribute. The lease_time attribute on the destination server must never be less than that on the source since this would result in premature expiration of leases granted by the source server. Upon migration in which state is @@ -4319,21 +6152,21 @@ sees a real or simulated server reboot), the client should fetch the value of lease_time on the new (i.e., destination) server, and use it for subsequent locking requests. However the server must respect a grace period at least as long as the lease_time on the source server, in order to ensure that clients have ample time to reclaim their locks before potentially conflicting non-reclaimed locks are granted. The means by which the new server obtains the value of lease_time on the old server is left to the server implementations. It is not specified by the NFS version 4 protocol. -9. Client-Side Caching +10. Client-Side Caching Client-side caching of data, of file attributes, and of file names is essential to providing good performance with the NFS protocol. Providing distributed cache coherence is a difficult problem and previous versions of the NFS protocol have not attempted it. Instead, several NFS client implementation techniques have been used to reduce the problems that a lack of coherence poses for users. These techniques have not been clearly defined by earlier protocol specifications and it is often unclear what is valid or invalid client behavior. @@ -4344,21 +6177,21 @@ defines a more limited set of caching guarantees to allow locks and share reservations to be used without destructive interference from client side caching. In addition, the NFS version 4 protocol introduces a delegation mechanism which allows many decisions normally made by the server to be made locally by clients. This mechanism provides efficient support of the common cases where sharing is infrequent or where sharing is read-only. -9.1. Performance Challenges for Client-Side Caching +10.1. Performance Challenges for Client-Side Caching Caching techniques used in previous versions of the NFS protocol have been successful in providing good performance. However, several scalability challenges can arise when those techniques are used with very large numbers of clients. This is particularly true when clients are geographically distributed which classically increases the latency for cache revalidation requests. The previous versions of the NFS protocol repeat their file data cache validation requests at the time the file is opened. This @@ -4368,42 +6201,42 @@ In this case, repeated reference to the server to find that no conflicts exist is expensive. A better option with regards to performance is to allow a client that repeatedly opens a file to do so without reference to the server. This is done until potentially conflicting operations from another client actually occur. A similar situation arises in connection with file locking. Sending file lock and unlock requests to the server as well as the read and write requests necessary to make data caching consistent with the - locking semantics (see Section 9.3.2 "Data Caching and File Locking") - can severely limit performance. When locking is used to provide - protection against infrequent conflicts, a large penalty is incurred. - This penalty may discourage the use of file locking by applications. + locking semantics (see Section 10.3.2) can severely limit + performance. When locking is used to provide protection against + infrequent conflicts, a large penalty is incurred. This penalty may + discourage the use of file locking by applications. The NFS version 4 protocol provides more aggressive caching strategies with the following design goals: o Compatibility with a large range of server semantics. o Provide the same caching benefits as previous versions of the NFS protocol when unable to provide the more aggressive model. o Requirements for aggressive caching are organized so that a large portion of the benefit can be obtained even when not all of the requirements can be met. The appropriate requirements for the server are discussed in later - sections in which specific forms of caching are covered. (see - Section 9.4 "Open Delegation"). + sections in which specific forms of caching are covered (see + Section 10.4). -9.2. Delegation and Callbacks +10.2. Delegation and Callbacks Recallable delegation of server responsibilities for a file to a client improves performance by avoiding repeated requests to the server in the absence of inter-client conflict. With the use of a "callback" RPC from server to client, a server recalls delegated responsibilities when another client engages in sharing of a delegated file. A delegation is passed from the server to the client, specifying the object of the delegation and the type of delegation. There are @@ -4448,32 +6281,32 @@ At the time the client receives a delegation recall, it may have substantial state that needs to be flushed to the server. Therefore, the server should allow sufficient time for the delegation to be returned since it may involve numerous RPCs to the server. If the server is able to determine that the client is diligently flushing state to the server as a result of the recall, the server may extend the usual time allowed for a recall. However, the time allowed for recall completion should not be unbounded. An example of this is when responsibility to mediate opens on a given - file is delegated to a client (see Section 9.4 "Open Delegation"). - The server will not know what opens are in effect on the client. - Without this knowledge the server will be unable to determine if the - access and deny state for the file allows any particular open until - the delegation for the file has been returned. + file is delegated to a client (see Section 10.4). The server will + not know what opens are in effect on the client. Without this + knowledge the server will be unable to determine if the access and + deny state for the file allows any particular open until the + delegation for the file has been returned. A client failure or a network partition can result in failure to respond to a recall callback. In this case, the server will revoke the delegation which in turn will render useless any modified state still on the client. -9.2.1. Delegation Recovery +10.2.1. Delegation Recovery There are three situations that delegation recovery must deal with: o Client reboot or restart o Server reboot or restart o Network partition (full or callback-only) In the event the client reboots or restarts, the failure to renew @@ -4490,23 +6323,22 @@ To allow for this type of client recovery, the server MAY extend the period for delegation recovery beyond the typical lease expiration period. This implies that requests from other clients that conflict with these delegations will need to wait. Because the normal recall process may require significant time for the client to flush changed state to the server, other clients need be prepared for delays that occur because of a conflicting delegation. This longer interval would increase the window for clients to reboot and consult stable storage so that the delegations can be reclaimed. For open delegations, such delegations are reclaimed using OPEN with a claim - type of CLAIM_DELEGATE_PREV. (See Section 9.5 "Data Caching and - Revocation" and Section 14.18 "Operation 18: OPEN" for discussion of - open delegation and the details of OPEN respectively). + type of CLAIM_DELEGATE_PREV. (See Section 10.5 and Section 15.18 for + discussion of open delegation and the details of OPEN respectively). A server MAY support a claim type of CLAIM_DELEGATE_PREV, but if it does, it MUST NOT remove delegations upon SETCLIENTID_CONFIRM, and instead MUST, for a period of time no less than that of the value of the lease_time attribute, maintain the client's delegations to allow time for the client to issue CLAIM_DELEGATE_PREV requests. The server that supports CLAIM_DELEGATE_PREV MUST support the DELEGPURGE operation. When the server reboots or restarts, delegations are reclaimed (using @@ -4542,55 +6374,54 @@ change) will have the same effect. A recall request will fail and revocation of the delegation will result. A client normally finds out about revocation of a delegation when it uses a stateid associated with a delegation and receives the error NFS4ERR_EXPIRED. It also may find out about delegation revocation after a client reboot when it attempts to reclaim a delegation and receives that same error. Note that in the case of a revoked write open delegation, there are issues because data may have been modified by the client whose delegation is revoked and separately by other - clients. See Section 9.5.1 "Revocation Recovery for Write Open - Delegation" for a discussion of such issues. Note also that when - delegations are revoked, information about the revoked delegation - will be written by the server to stable storage (as described in - Section 8.6 "Crash Recovery"). This is done to deal with the case in + clients. See Section 10.5.1 for a discussion of such issues. Note + also that when delegations are revoked, information about the revoked + delegation will be written by the server to stable storage (as + described in Section 9.6). This is done to deal with the case in which a server reboots after revoking a delegation but before the client holding the revoked delegation is notified about the revocation. -9.3. Data Caching +10.3. Data Caching When applications share access to a set of files, they need to be implemented so as to take account of the possibility of conflicting access by another application. This is true whether the applications in question execute on different clients or reside on the same client. Share reservations and record locks are the facilities the NFS version 4 protocol provides to allow applications to coordinate access by providing mutual exclusion facilities. The NFS version 4 protocol's data caching must be implemented such that it does not invalidate the assumptions that those using these facilities depend upon. -9.3.1. Data Caching and OPENs +10.3.1. Data Caching and OPENs In order to avoid invalidating the sharing assumptions that applications rely on, NFS version 4 clients should not provide cached data to applications or modify it on behalf of an application when it would not be valid to obtain or modify that same data via a READ or WRITE operation. - Furthermore, in the absence of open delegation (see Section 9.4 "Open - Delegation") two additional rules apply. Note that these rules are - obeyed in practice by many NFS version 2 and version 3 clients. + Furthermore, in the absence of open delegation (see Section 10.4) two + additional rules apply. Note that these rules are obeyed in practice + by many NFS version 2 and version 3 clients. o First, cached data present on a client must be revalidated after doing an OPEN. Revalidating means that the client fetches the change attribute from the server, compares it with the cached change attribute, and if different, declares the cached data (as well as the cached attributes) as invalid. This is to ensure that the data for the OPENed file is still correctly reflected in the client's cache. This validation must be done at least when the client's OPEN operation includes DENY=WRITE or BOTH thus terminating a period in which other clients may have had the @@ -4613,21 +6444,21 @@ a file OPENed for write. This is complementary to the first rule. If the data is not flushed at CLOSE, the revalidation done after client OPENs as file is unable to achieve its purpose. The other aspect to flushing the data before close is that the data must be committed to stable storage, at the server, before the CLOSE operation is requested by the client. In the case of a server reboot or restart and a CLOSEd file, it may not be possible to retransmit the data to be written to the file. Hence, this requirement. -9.3.2. Data Caching and File Locking +10.3.2. Data Caching and File Locking For those applications that choose to use file locking instead of share reservations to exclude inconsistent file access, there is an analogous set of constraints that apply to client side data caching. These rules are effective only if the file locking is used in a way that matches in an equivalent way the actual READ and WRITE operations executed. This is as opposed to file locking that is based on pure convention. For example, it is possible to manipulate a two-megabyte file by dividing the file into two one-megabyte regions and protecting access to the two regions by file locks on @@ -4691,38 +6522,38 @@ unrelated unlock. However, it would not be valid to write the entire block in which that single written byte was located since it includes an area that is not locked and might be locked by another client. Client implementations can avoid this problem by dividing files with modified data into those for which all modifications are done to areas covered by an appropriate record lock and those for which there are modifications not covered by a record lock. Any writes done for the former class of files must not include areas not locked and thus not modified on the client. -9.3.3. Data Caching and Mandatory File Locking +10.3.3. Data Caching and Mandatory File Locking Client side data caching needs to respect mandatory file locking when it is in effect. The presence of mandatory file locking for a given file is indicated when the client gets back NFS4ERR_LOCKED from a READ or WRITE on a file it has an appropriate share reservation for. When mandatory locking is in effect for a file, the client must check for an appropriate file lock for data being read or written. If a lock exists for the range being read or written, the client may satisfy the request using the client's validated cache. If an appropriate file lock is not held for the range of the read or write, the read or write request must not be satisfied by the client's cache and the request must be sent to the server for processing. When a read or write request partially overlaps a locked region, the request should be subdivided into multiple pieces with each region (locked or not) treated appropriately. -9.3.4. Data Caching and File Identity +10.3.4. Data Caching and File Identity When clients cache data, the file data needs to be organized according to the filesystem object to which the data belongs. For NFS version 3 clients, the typical practice has been to assume for the purpose of caching that distinct filehandles represent distinct filesystem objects. The client then has the choice to organize and maintain the data cache on this basis. In the NFS version 4 protocol, there is now the possibility to have significant deviations from a "one filehandle per object" model @@ -4758,21 +6589,21 @@ fileid attribute for both of the handles, then it cannot be determined whether the two objects are the same. Therefore, operations which depend on that knowledge (e.g., client side data caching) cannot be done reliably. o If GETATTR directed to the two filehandles returns different values for the fileid attribute, then they are distinct objects. o Otherwise they are the same object. -9.4. Open Delegation +10.4. Open Delegation When a file is being OPENed, the server may delegate further handling of opens and closes for that file to the opening client. Any such delegation is recallable, since the circumstances that allowed for the delegation are subject to change. In particular, the server may receive a conflicting OPEN from another client, the server must recall the delegation before deciding whether the OPEN from the other client may be granted. Making a delegation is up to the server and clients should not assume that any particular OPEN either will or will not result in an open delegation. The following is a typical @@ -4820,41 +6651,40 @@ For a read open delegation, opens that cannot be handled locally (opens for write or that deny read access) must be sent to the server. When an open delegation is made, the response to the OPEN contains an open delegation structure which specifies the following: o the type of delegation (read or write) o space limitation information to control flushing of data on close - (write open delegation only, see Section 9.4.1 "Open Delegation - and Data Caching") + (write open delegation only, see Section 10.4.1) o an nfsace4 specifying read and write permissions o a stateid to represent the delegation for READ and WRITE The delegation stateid is separate and distinct from the stateid for the OPEN proper. The standard stateid, unlike the delegation stateid, is associated with a particular lock_owner and will continue to be valid after the delegation is recalled and the file remains open. When a request internal to the client is made to open a file and open delegation is in effect, it will be accepted or rejected solely on the basis of the following conditions. Any requirement for other checks to be made by the delegate should result in open delegation being denied so that the checks can be made by the server itself. o The access and deny bits for the request and the file as described - in Section 8.9 "Share Reservations". + in Section 9.9. o The read and write permissions as determined below. The nfsace4 passed with delegation can be used to avoid frequent ACCESS calls. The permission check should be as follows: o If the nfsace4 indicates that the open may be done, then it should be granted without reference to the server. o If the nfsace4 indicates that the open may not be done, then an @@ -4871,21 +6701,21 @@ The use of delegation together with various other forms of caching creates the possibility that no server authentication will ever be performed for a given user since all of the user's requests might be satisfied locally. Where the client is depending on the server for authentication, the client should be sure authentication occurs for each user by use of the ACCESS operation. This should be the case even if an ACCESS operation would not be required otherwise. As mentioned before, the server may enforce frequent authentication by returning an nfsace4 denying all access with every open delegation. -9.4.1. Open Delegation and Data Caching +10.4.1. Open Delegation and Data Caching OPEN delegation allows much of the message overhead associated with the opening and closing files to be eliminated. An open when an open delegation is in effect does not require that a validation message be sent to the server. The continued endurance of the "read open delegation" provides a guarantee that no OPEN for write and thus no write has occurred. Similarly, when closing a file opened for write and if write open delegation is in effect, the data written does not have to be flushed to the server until the open delegation is recalled. The continued endurance of the open delegation provides a @@ -4934,35 +6764,35 @@ With respect to authentication, flushing modified data to the server after a CLOSE has occurred may be problematic. For example, the user of the application may have logged off the client and unexpired authentication credentials may not be present. In this case, the client may need to take special care to ensure that local unexpired credentials will in fact be available. This may be accomplished by tracking the expiration time of credentials and flushing data well in advance of their expiration or by making private copies of credentials to assure their availability when needed. -9.4.2. Open Delegation and File Locks +10.4.2. Open Delegation and File Locks When a client holds a write open delegation, lock operations may be performed locally. This includes those required for mandatory file locking. This can be done since the delegation implies that there can be no conflicting locks. Similarly, all of the revalidations that would normally be associated with obtaining locks and the flushing of data associated with the releasing of locks need not be done. When a client holds a read open delegation, lock operations are not performed locally. All lock operations, including those requesting non-exclusive locks, are sent to the server for resolution. -9.4.3. Handling of CB_GETATTR +10.4.3. Handling of CB_GETATTR The server needs to employ special handling for a GETATTR where the target is a file that has a write open delegation in effect. The reason for this is that the client holding the write delegation may have modified the data and the server needs to reflect this change to the second client that submitted the GETATTR. Therefore, the client holding the write delegation needs to be interrogated. The server will use the CB_GETATTR operation. The only attributes that the server can reliably query via CB_GETATTR are size and change. @@ -5093,21 +6923,21 @@ CB_GETATTR and responds to the second client as in the last step. This methodology resolves issues of clock differences between client and server and other scenarios where the use of CB_GETATTR break down. It should be noted that the server is under no obligation to use CB_GETATTR and therefore the server MAY simply recall the delegation to avoid its use. -9.4.4. Recall of Open Delegation +10.4.4. Recall of Open Delegation The following events necessitate recall of an open delegation: o Potentially conflicting OPEN request (or READ/WRITE done with "special" stateid) o SETATTR issued by another client o REMOVE request for the file @@ -5135,21 +6965,21 @@ no previous CLOSE operation has been sent to the server, a CLOSE operation must be sent to the server. o If a file has other open references at the client, then OPEN operations must be sent to the server. The appropriate stateids will be provided by the server for subsequent use by the client since the delegation stateid will not longer be valid. These OPEN requests are done with the claim type of CLAIM_DELEGATE_CUR. This will allow the presentation of the delegation stateid so that the client can establish the appropriate rights to perform the OPEN. - (see Section 14.18"Operation 18: OPEN" for details.) + (see Section 15.18 for details.) o If there are granted file locks, the corresponding LOCK operations need to be performed. This applies to the write open delegation case only. o For a write open delegation, if at the time of recall the file is not open for write, all modified data for the file must be flushed to the server. If the delegation had not existed, the client would have done this data flush before the CLOSE operation. @@ -5183,21 +7013,21 @@ closes to the server, except as part of delegation return. Only in the case of closing the open that resulted in obtaining the delegation would clients be likely to do this early, since, in that case, the close once done will not be undone. Regardless of the client's choices on scheduling these actions, all must be performed before the delegation is returned, including (when applicable) the close that corresponds to the open that resulted in the delegation. These actions can be performed either in previous requests or in previous operations in the same COMPOUND request. -9.4.5. Clients that Fail to Honor Delegation Recalls +10.4.5. Clients that Fail to Honor Delegation Recalls A client may fail to respond to a recall for various reasons, such as a failure of the callback path from server to the client. The client may be unaware of a failure in the callback path. This lack of awareness could result in the client finding out long after the failure that its delegation has been revoked, and another client has modified the data for which the client had a delegation. This is especially a problem for the client that held a write delegation. The server also has a dilemma in that the client that fails to @@ -5226,36 +7056,36 @@ time after the server attempted to recall the delegation. This period of time MUST NOT be less than the value of the lease_time attribute. o When the client holds a delegation, it can not rely on operations, except for RENEW, that take a stateid, to renew delegation leases across callback path failures. The client that wants to keep delegations in force across callback path failures must use RENEW to do so. -9.4.6. Delegation Revocation +10.4.6. Delegation Revocation At the point a delegation is revoked, if there are associated opens on the client, the applications holding these opens need to be notified. This notification usually occurs by returning errors for READ/WRITE operations or when a close is attempted for the open file. If no opens exist for the file at the point the delegation is revoked, then notification of the revocation is unnecessary. However, if there is modified data present at the client for the file, the user of the application should be notified. Unfortunately, it may not be possible to notify the user since active applications - may not be present at the client. See Section 9.5.1 "Revocation - Recovery for Write Open Delegation" for additional details. + may not be present at the client. See Section 10.5.1 for additional + details. -9.5. Data Caching and Revocation +10.5. Data Caching and Revocation When locks and delegations are revoked, the assumptions upon which successful caching depend are no longer guaranteed. For any locks or share reservations that have been revoked, the corresponding owner needs to be notified. This notification includes applications with a file open that has a corresponding delegation which has been revoked. Cached data associated with the revocation must be removed from the client. In the case of modified data existing in the client's cache, that data must be removed from the client without it being written to the server. As mentioned, the assumptions made by the client are no @@ -5271,21 +7101,21 @@ open file or on the close. Where the methods available to a client make such notification impossible because errors for certain operations may not be returned, more drastic action such as signals or process termination may be appropriate. The justification for this is that an invariant for which an application depends on may be violated. Depending on how errors are typically treated for the client operating environment, further levels of notification including logging, console messages, and GUI pop-ups may be appropriate. -9.5.1. Revocation Recovery for Write Open Delegation +10.5.1. Revocation Recovery for Write Open Delegation Revocation recovery for a write open delegation poses the special issue of modified data in the client cache while the file is not open. In this situation, any client which does not flush modified data to the server on each close must ensure that the user receives appropriate notification of the failure as a result of the revocation. Since such situations may require human action to correct problems, notification schemes in which the appropriate user or administrator is notified may be necessary. Logging and console messages are typical examples. @@ -5304,21 +7134,21 @@ contents in these situations or mark the results specially to warn users of possible problems. Saving of such modified data in delegation revocation situations may be limited to files of a certain size or might be used only when sufficient disk space is available within the target filesystem. Such saving may also be restricted to situations when the client has sufficient buffering resources to keep the cached copy available until it is properly stored to the target filesystem. -9.6. Attribute Caching +10.6. Attribute Caching The attributes discussed in this section do not include named attributes. Individual named attributes are analogous to files and caching of the data for these needs to be handled just as data caching is for ordinary files. Similarly, LOOKUP results from an OPENATTR directory are to be cached on the same basis as any other pathnames and similarly for directory contents. Clients may cache file attributes obtained from the server and use them to avoid subsequent GETATTR requests. Such caching is write @@ -5398,21 +7228,21 @@ client will either eventually have to write the access time to the server with bad performance effects, or it would never update the server's time_access, thereby resulting in a situation where an application that caches access time between a close and open of the same file observes the access time oscillating between the past and present. The time_access attribute always means the time of last access to a file by a read that was satisfied by the server. This way clients will tend to see only time_access changes that go forward in time. -9.7. Data and Metadata Caching and Memory Mapped Files +10.7. Data and Metadata Caching and Memory Mapped Files Some operating environments include the capability for an application to map a file's content into the application's address space. Each time the application accesses a memory location that corresponds to a block that has not been loaded into the address space, a page fault occurs and the file is read (or if the block does not exist in the file, the block is allocated and then instantiated in the application's address space). As long as each memory mapped access to the file requires a page @@ -5504,21 +7334,21 @@ are record locks for. o Clients and servers MAY deny a record lock on a file they know is memory mapped. o A client MAY deny memory mapping a file that it knows requires mandatory locking for I/O. If mandatory locking is enabled after the file is opened and mapped, the client MAY deny the application further access to its mapped file. -9.8. Name Caching +10.8. Name Caching The results of LOOKUP and READDIR operations may be cached to avoid the cost of subsequent LOOKUP operations. Just as in the case of attribute caching, inconsistencies may arise among the various client caches. To mitigate the effects of these inconsistencies and given the context of typical filesystem APIs, an upper time boundary is maintained on how long a client name cache entry can be kept without verifying that the entry has not been made invalid by a directory change operation performed by another client. @@ -5553,21 +7383,21 @@ directories when the contents of the corresponding directory is modified. For a client to use the change_info4 information appropriately and correctly, the server must report the pre and post operation change attribute values atomically. When the server is unable to report the before and after values atomically with respect to the directory operation, the server must indicate that fact in the change_info4 return value. When the information is not atomically reported, the client should not assume that other clients have not changed the directory. -9.9. Directory Caching +10.9. Directory Caching The results of READDIR operations may be used to avoid subsequent READDIR operations. Just as in the cases of attribute and name caching, inconsistencies may arise among the various client caches. To mitigate the effects of these inconsistencies, and given the context of typical filesystem APIs, the following rules should be followed: o Cached READDIR information for a directory which is not obtained in a single READDIR operation must always be a consistent snapshot @@ -5596,21 +7426,21 @@ directories when the contents of the corresponding directory is modified. For a client to use the change_info4 information appropriately and correctly, the server must report the pre and post operation change attribute values atomically. When the server is unable to report the before and after values atomically with respect to the directory operation, the server must indicate that fact in the change_info4 return value. When the information is not atomically reported, the client should not assume that other clients have not changed the directory. -10. Minor Versioning +11. Minor Versioning To address the requirement of an NFS protocol that can evolve as the need arises, the NFS version 4 protocol contains the rules and framework to allow for future minor changes or versioning. The base assumption with respect to minor versioning is that any future accepted minor version must follow the IETF process and be documented in a standards track RFC. Therefore, each minor version number will correspond to an RFC. Minor version zero of the NFS version 4 protocol is represented by this RFC. The COMPOUND @@ -5710,543 +7540,2072 @@ This rule allows for the introduction of new functionality and forces the use of implementation experience before designating a feature as mandatory. 13. A client MUST NOT attempt to use a stateid, filehandle, or similar returned object from the COMPOUND procedure with minor version X for another COMPOUND procedure with minor version Y, where X != Y. -11. Internationalization +12. Internationalization - The primary issue in which NFS version 4 needs to deal with - internationalization, or I18N, is with respect to file names and - other strings as used within the protocol. The choice of string - representation must allow reasonable name/string access to clients + This chapter describes the string-handling aspects of the NFS version + 4 protocol, and how they address issues related to + internationalization, including issues related to UTF-8, + normalization, string preparation, case folding, and handling of + internationalization issues related to domains. + + The NFS version 4 protocol needs to deal with internationalization, + or I18N, with respect to file names and other strings as used within + the protocol. The choice of string representation must allow for + reasonable name/string access to clients, applications, and users which use various languages. The UTF-8 encoding of the UCS as defined by [7] allows for this type of access and follows the policy described in "IETF Policy on Character Sets and Languages", [8]. - [9], otherwise know as "stringprep", documents a framework for using - Unicode/UTF-8 in networking protocols, so as "to increase the - likelihood that string input and string comparison work in ways that - make sense for typical users throughout the world." A protocol must - define a profile of stringprep "in order to fully specify the - processing options." The remainder of this Internationalization - section defines the NFS version 4 stringprep profiles. Much of - terminology used for the remainder of this section comes from - stringprep. + In implementing such policies, it is important to understand and + respect the nature of NFS version 4 as a means by which client + implementations may invoke operations on remote file systems. Server + implementations act as a conduit to a range of file system + implementations that the NFS version 4 server typically invokes + through a virtual-file-system interface. - There are three UTF-8 string types defined for NFS version 4: - utf8str_cs, utf8str_cis, and utf8str_mixed. Separate profiles are - defined for each. Each profile defines the following, as required by - stringprep: + Keeping this context in mind, one needs to understand that the file + systems with which clients will be interacting will generally not be + devoted solely to access using NFS version 4. Local access and its + requirements will generally be important and often access over other + remote file access protocols will be as well. It is generally a + functional requirement in practice for the users of the NFS version 4 + protocol (although it may be formally out of scope for this document) + for the implementation to allow files created by other protocols and + by local operations on the file system to be accessed using NFS + version 4 as well. - o The intended applicability of the profile + It also needs to be understood that a considerable portion of file + name processing will occur within the implementation of the file + system rather than within the limits of the NFS version 4 server + implementation per se. As a result, cetain aspects of name + processing may change as the locus of processing moves from file + system to file system. As a result of these factors, the protocol + does not enforce uniformity of processing NFS version 4 server + requests on the server as a whole. Because the server interacts with + existing file system implementations, the same server handling will + produce different behavior when interacting with different file + system implementations. To attempt to require uniform behavior, and + treat the the protocol server and the file system as a unified + application, would considerably limit the usefulness of the protocol. - o The character repertoire that is the input and output to - stringprep (which is Unicode 3.2 for referenced version of - stringprep) +12.1. Use of UTF-8 - o The mapping tables from stringprep used (as described in section 3 - of stringprep) + As mentioned above, UTF-8 is used as a convenient way to encode + Unicode which allows clients that have no internationalization + requirements to avoid these issues since the mapping of ASCII names + to UTF-8 is the identity. - o Any additional mapping tables specific to the profile +12.1.1. Relation to Stringprep - o The Unicode normalization used, if any (as described in section 4 - of stringprep) + RFC 3454 [9], otherwise known as "stringprep", documents a framework + for using Unicode/UTF-8 in networking protocols, intended "to + increase the likelihood that string input and string comparison work + in ways that make sense for typical users throughout the world." A + protocol conforming to this framework must define a profile of + stringprep "in order to fully specify the processing options." NFS + version 4, while it does make normative references to stringprep and + uses elements of that framework, it does not, for reasons that are + explained below, conform to that framework, for all of the strings + that are used within it. - o The tables from stringprep listing of characters that are - prohibited as output (as described in section 5 of stringprep) + In addition to some specific issues which have caused stringprep to + add confusion in handling certain characters for certain languages, + there are a number of reasons why stringprep profiles are not + suitable for describing NFS version 4. - o The bidirectional string testing used, if any (as described in - section 6 of stringprep) + o Restricting the character repertoire to Unicode 3.2, as required + by stringprep is unduly constricting. - o Any additional characters that are prohibited as output specific - to the profile + o Many of the character tables in stringprep are inappropriate + because of this limited character repertoire, so that normative + reference to stringprep is not desirable in many case and instead, + we allow more flexibility in the definition of case mapping + tables. - Stringprep discusses Unicode characters, whereas NFS version 4 - renders UTF-8 characters. Since there is a one to one mapping from - UTF-8 to Unicode, where ever the remainder of this document refers to - to Unicode, the reader should assume UTF-8. + o Because of the presence of different file systems, the specifics + of processing are not fully defined and some aspects that are are + RECOMMENDED, rather than REQUIRED. - Much of the text for the profiles comes from [9]. + Despite these issues, in many cases the general structure of + stringprep profiles, consisting of sections which deal with the + applicability of the description, the character repertoire, charcter + mapping, normalization, prohibited characters, and issues of the + handling (i.e. possible prohibition) of bidirectional strings, is a + convenient way to describe the string handling which is needed and + will be used where appropriate. -11.1. Stringprep profile for the utf8str_cs type +12.1.2. Normalization, Equivalence, and Confusability - Every use of the utf8str_cs type definition in the NFS version 4 - protocol specification follows the profile named nfs4_cs_prep. + Unicode has defined several equivalence relationships among the set + of possible strings. Understanding the nature and purpose of these + equivalence relations is important to understand the handling of + unicode strings within NFS version 4. -11.1.1. Intended applicability of the nfs4_cs_prep profile + o Some string pairs are thought as only differing in the way accents + and other diacritics are encoded. Such string pairs are called + "canonically equivalent". For example, the character LATIN SMALL + LETTER E WITH ACUTE (U+00E9) is defined as equivalent to the + string consisting of LATIN SMALL LETTER E followed by COMBINING + ACUTE ACCENT (U+0065, U+0301). - The utf8str_cs type is a case sensitive string of UTF-8 characters. - Its primary use in NFS Version 4 is for naming components and - pathnames. Components and pathnames are stored on the server's - filesystem. Two valid distinct UTF-8 strings might be the same after - processing via the utf8str_cs profile. If the strings are two names - inside a directory, the NFS version 4 server will need to either: + o Additionally there is an equvalence relation of "compatibility + equivalence". Two canonically equivalent strings are necessarily + compatibility equivalent, although not the converse. An example + of compatibility equivalent strings which are not canonically + equivalent are GREEK CAPITAL LETTER OMEGA (U+03A9) and OHM SIGN + (U+2129). These are identical in appearance while other + compatibility equivalent strings are not. Another example would + be "x2" and the two character string denoting x-squared which are + clearly differnt in appearance although compatibility equivalent + and not canonically equivalent. These have Unicode encodings + LATIN SMALL LETTER X, DIGIT TWO (U+0078, U+0032) and LATIN SMALL + LETTER X, SUPERSCRIPT TWO (U+0078, U+00B2), - o disallow the creation of a second name if it's post processed form + One way to deal with these equivalence relations is via + normalization. A normalization form maps all strings to correspond + normalized string in such a fashion that all strings that are + equivalent (canonically or compatibly, depending on the form) are + mapped to the same value. Thus the image of the mapping is a subset + of Unicode strings conceived as the representives of the equivalence + classes defined by the chosed equivalence relation. + + In the NFS version 4 protocol, handling of issues related to + internationalization with regard to normalization follows one of two + basic patterns: + + o For strings whose function is related to other internet standards, + such as server and domain naming, the normalization form defined + by the appropriate internet standards is used. For server and + domain naming, this involves normalization form NKFC as specified + in [10] + + o For other strings, particular those passed by the server to file + system implementations, normalization requirements are the + province of the file system and the job of this specification is + not to specify a particular form but to make sure that + interoperability is maximmized, even when clients and server-based + file systems may have different preferences. + + A related but distinct issue concerns string confusability. This can + occur when two strings (including single-charcter strings) having a + similar appearance. There have been attempts to define uniform + processing in an attempt to avoid such confusion (see stringprep [9]) + but the results have often added to confusion. + + Some examples of possible confusions and proposed processing intended + to reduce/avoid confusions: + + o Deletion of characters supposed to be invisible and appropriately + ignored, justifying their deletion, including, WORD JOINER + (U+2060), and the ZERO WIDTH SPACE (U+200B). + + o Deletion of characters supposed to not bear semantics and only + affect glyph choice, including the ZERO WIDTH NON-JOINER (U+200C) + and the ZERO WIDTH JOINER (U+200D), where the deletion turns out + to be a problem for Farsi speakers. + + o Prohibition of space characters such as the EM SPACE (U+2003), the + EN SPACE (U+2002), and the THIN SPACE (U+2009). + + In addition, character pairs which apprear very similar and could and + often do result in confusion. In addition to what Unicode defines as + "compatibility equivalence", there are a considerable number of + additional character pairs that could cause confusion. This includes + characters such as LATIN CAPITAL LETTER O (U+004F) and DIGIT ZERO + (U+0030), and CYRILLIC SMALL LETTER ER (U+0440) LATIN SMALL LETTER P + (U+0070) (also with MATHEMATICAL BOLD SMALL P (U+1D429) and GREEK + SMALL LETTER RHO (U+1D56, for good measure). + + NFS version 4, as it does with normalization, takes a two-part + approach to this issue: + + o For strings whose function is related to other internet standards, + such as server and domain naming, any string processing to address + the confusability issue is defined by the appropriate internet + standards is used. For server and domain naming, this is the + responsibility of IDNA as described in [10]. + + o For other strings, particularly those passed by the server to file + system implementations, any such preparation requirements + including the choice of how, or whether to address the + confusability issue, are the responsibility of the file system to + define, and for this specification to try to add its own set would + add unacceptably to complexity, and make many files accessible + locally and by other remote file access protocols, inaccessible by + NFS version 4. This specification defines how the protocol + maximizes interoperability in the face of different file system + implementations. + + NFS version 4 does allow file systems to map and to reject + characters, including those likely to result in confusion, since + file systems may choose to do such things. It defines what the + client will see in such cases, in order to limit problems that can + arise when a file name is created and it appears to have a + different name from the one it is assigned when the name is + created. + +12.2. String Type Overview + +12.2.1. Overall String Class Divisions + + NFS version 4 has to deal with with a large set of diffreent types of + strings and because of the different role of each, + internationalization issues will be different for each: + + o For some types of strings, the fundamental internationalization- + related decisions are the province of the file system or the + security-handling functions of the server and the protocol's job + is to establish the rules under which file systems and servers are + allowed to exercise this freedom, to avoid adding to confusion. + + o In other cases, the fundamental internationalization issues are + the responsibility of other IETF groups and our jobis simply to + reference those and perhaps make a few choices as to how they are + to be used (e.g. U-labels vs. A-labels). + + o There are also cases in which a string has a small amount of NFS + version 4 processing which results in one or more strings being + referred to one of the other categories. + + We will divide strings to be dealt with into the following classes: + + MIX indicating that there is small amount of preparatory processing + that either picks an appropriate modes of internationalization + handling or divides the string into a set of (two) strings with a + different mode internationalization handling for each. The + details are discussed in the section "Types with Pre-processing to + Resolve Mixture Issues". + + NIP indicating that, for various reasons, there is no need for + internationalization-specific processing to be performed. The + specifics of the various string types handled in this way are + described in the section "String Types without + Internationalization Processing". + + INET indicating that the string needs to be processed in a fashion + is goverened by non-NFS-specific internet specifications. The + details are discussed in the section "Types with Processing + Defined by Other Internet Areas". + + NFS indicating that the string needs to be processed in a fashion is + goverened by NFSv4-specific consideration. The primary focus is + on enabling flexibility for the various file systems to be + accessed and is described in the section "String Types with NFS- + specific Processing". + +12.2.2. Divisions by Typedef Parent types + + There are a number of different string types within NFS version 4 and + internationalization handling will be different for different types + of strings. Each the types will be in one of four groups based on + the parent type that specifies the nature of its relationship to utf8 + and ascii. + + utf8_should/SHOULD: indicating that strings of this type should be + UTF-8 but clients and servers will not check for valid UTF-8 + encoding. + + utf8val_should/VSHOULD: indicating that strings of this type should + be and generally will be in the form of the UTF-8 encoding of + Unicode. Strings in most cases will be checked by the server for + valid UTF-8 but for certain file systems, such checking may be + inhibited. + + utf8val_must/VMUST: indicating that strings of this type must be in + the form of the UTF-8 encoding of Unicode. Strings will be + checked by the server for valid UTF-8 and the server should ensure + that when sent to the client, they are valid UTF-8. + + ascii_must/ASCII: indicating that strings of this type must be pure + ASCII, and thus automatically UTF-8. The processing of these + string must ensure that they are only have ASCII characters but + this need not be a separate step if any normally required check + for validity inherently assures that only ASCII characters are + present. + +12.2.3. Individual Types and Their Handling + + The first table outlines the handling for the primary string types, + i.e. those not derived as a prefix or a suffix from a mixture type. + + +-----------------+---------+-------+-------------------------------+ + | Type | Parent | Class | Explanation | + +-----------------+---------+-------+-------------------------------+ + | comptag4 | SHOULD | NIP | Should be utf8 but no | + | | | | validation by server or | + | | | | client is to be done. | + | component4 | VSHOULD | NFS | Should be utf8 but clients | + | | | | may need to access file | + | | | | systems with a different name | + | | | | structure. files systems with | + | | | | non-utf8 names. | + | linktext4 | VSHOULD | NFS | Should be utf8 since text may | + | | | | include name components. | + | | | | Because of the need to access | + | | | | existing file systems, this | + | | | | check may be inhibited. | + | fattr4_mimetype | ASCII | NIP | All mime types are ascii so | + | | | | no specific utf8 processing | + | | | | is required, given that you | + | | | | are comparing to that list. | + +-----------------+---------+-------+-------------------------------+ + + Table 5 + + There are a number of string types that are compound in that they may + consist of multiple conjoined strings with different utf8-related + processing for each. + + +---------+--------+-------+----------------------------------------+ + | Type | Parent | Class | Explanation | + +---------+--------+-------+----------------------------------------+ + | prin4 | VMUST | MIX | Consists of two parts separated by an | + | | | | at-sign, a prinpfx4 and a prinsfx4. | + | | | | These are described in the next table. | + | server4 | VMUST | MIX | Is either an IP address (serveraddr4) | + | | | | which has to be pure ascii or a server | + | | | | name svrname4, which is described | + | | | | immediately below. | + +---------+--------+-------+----------------------------------------+ + + Table 6 + + The last table describes the components of the compound types + described above. + + +----------+-------+------+-----------------------------------------+ + | Type | Class | Def | Explanation | + +----------+-------+------+-----------------------------------------+ + | svraddr4 | ASCII | NIP | Server as IP address, whether IPv4 or | + | | | | IPv6, | + | svrname4 | VMUST | INET | Server name as returned by server. Not | + | | | | sent by client, except in | + | | | | VERIFY/NVERIFY. | + | prinsfx4 | VMUST | INET | Suffix part of principal, in the form | + | | | | of a domain name. | + | prinpfx4 | VMUST | NFS | Must match one of a list of valid users | + | | | | or groups for that particular domain. | + +----------+-------+------+-----------------------------------------+ + + Table 7 + +12.3. Errors Related to Strings + + When the client sends an invalid UTF-8 string in a context in which + UTF-8 is required, the server MUST return an NFS4ERR_INVAL error. + When the client sends an invalid UTF-8 string in a context in which + UTF-8 is recommended, the server SHOULD return an NFS4ERR_INVAL + error. These situations apply to cases in which inappropriate + prefixes are detected and where the count includes trailing bytes + that do not constitute a full UCS character. + + Where the client supplied string is valid UTF-8 but contains + characters that are not supported by the server file system as a + value for that string (e.g., names containing characters that have + more than two octets on a file system that supports UCS-2 characters + only, file name components containing slashes on file systems that do + not allow them in filename file name components), the server should + MUST return an NFS4ERR_BADCHAR error. + + Where a UTF-8 string is used as a file name component, and the file + system, while supporting all of the characters within the name, does + not allow that particular name to be used, the server should return + the error NFS4ERR_BADNAME. This includes file system prohibitions of + "." and ".." as file names for certain operations, and other such + similar constraints. It does not include use of strings with non- + preferred normalization modes. + + Where a UTF-8 string is used as a file name component, the file + system implementation MUST NOT return NFS4ERR_BADNAME, simply due to + a normalization mismatch. In such cases the implementation MAY + convert the string to its own preferred normalization mode before + performing the operation. As a result, a client cannot assume that a + file created with a name it specifies will have that name when the + directory is read. It may have instead, the name converted to the + file system's preferred normalization form. + + Where a UTF-8 string is used as other than a file name component and + the string does not meet the normalization requirements specified for + it, the error NFS4ERR_INVAL is returned. + +12.4. Types with Pre-processing to Resolve Mixture Issues + +12.4.1. Processing of Principal Strings + + Strings denoting principals (users or groups) MUST be UTF-8 but since + they consist of a principal prefix, an at-sign, and a domain, all + three of which either are checked for being UTF-8, or inherently are + UTF-8, checking the string as a whole for being UTF-8 is not + required. Although a server implementation may choose to make this + check on the string as whole, for example in converting it to + Unicode, the description within this document, will reflect a + processing model in which such checking happens after the division + into a principal prefix and suffix, the latter being in the form of a + domain name. + + The string should be scanned for at-signs. If there is more that one + at-sign, the string is considered invalid. For cases in which there + are no at-signs or the at-sign appears at the start of end of the + string see Interpreting owner and owner_group Otherwise, the portion + before the at-sign is dealt with as a prinpfx4 and the portion after + is dealt with as a prinsfx4. + +12.4.2. Processing of Server Id Strings + + Server id strings typically appear in responses (as attribute values) + and only appear in requests as attribute value presented to VERIFY + and NVERIFY. With that exception, they are not subject to server + validation and posible rejection. It is not expected that clients + will typically do such validation on receipt of responses but they + may as a way to check for proper server behavior. The responsibility + for sending correct UTF-8 strings is with the server. + + Servers are identified by either server names of IP addresses. Once + an id has been identified as an IP address, then there is no + processing specific to internationalization to be done, since such an + address must be ASCII to be valid. + + Identifiers which are not valid IP addresses are treated as server + names for which see below. There are fifteen top-level domains that + consist of two characters, each within the range a-f. Given that, it + is possible to have a string such as bb.bb.bb.bb, which might be + either an IP address or a server name. It is recommended that in + such cases, a check for a valid server name be done first and the + string interpreted as an IP address only if it found that the string + is not a server name. + +12.5. String Types without Internationalization Processing + + There are a number of types of strings which, for a number of + different reasons, do not require any internationalization-specific + handling, such as valdiation of UTF-8, normaliztion, or character + mapping or checking. This does not necessarily mean that the strings + need not be UTF-8. In some case, other checking on the string + ensures that they are valid UTF-8, without doing any checking + specific to internationalization. + + The following are the specific types: + + comptag4 strings are an aid to debugging and the sender should avoid + confusion by not using anything but valid UTF-8. But any work + validating the string or modifying it would just add complication + to a mechanism whose basic function is best supported by making it + not subject to any checking and having data maximally available to + be looked at in a network trace. + + fattr4_mimetype strings need to be validated by matching against a + list of valid mime types. Since these are all ASCII, no + processing specific to internationaliztion is required since + anything that does not match is invalid and anything which does + not obey the rules of UTF-8 will not be ASCII and consequently + will not match, and will be invalid. + + svraddr4 strings, in order to be valid, need to be ASCII, but if you + check them for validity, you have inherently checked that that + they are ASCII and thus UTF-8. + +12.6. Types with Processing Defined by Other Internet Areas + + There are two types of strings which NFS version 4 deals with whose + processing is defined by other Internet standards, and where issues + related to different handling choices by server operating systems or + server file systems do not apply. + + These are as follows: + + o Server names as they appear in the fs_locations attribute. Note + that for most purposes, such server names will only be sent by the + server to the client. The exception is use of the fs_locations + attribute in a VERIFY or NVERIFY operation. + + o Principal suffixes which are used to denote sets of users and + groups, and are in the form of domain names. + + The general rules for handling all of these domain-related strings + are similar and independent of role of the sender or receiver as + client or sender, although the consequences of failure to obey these + rules may be different for client or server. + + The string sent SHOULD be in the form of a U-label although it MAY be + in the form of an A-label or a UTF-8 string that would not map to + itself when canonicalized by applying ToUnicode(ToASCII(...)). The + receiver needs to be able to accept domain and server names in any of + the formats allowed. The server MUST reject, using the the error + NFS4ERR_INVAL, a string which is not valid UTF-8 or which begins with + "xn--" and violates the rules for a valid A-label. + + When a domain string is part of id@domain or group@domain, the server + SHOULD map domain strings which are A-labels or are UTF-8 domain + names which are not U-labels, to the corresponding U-label, using + ToUnicode(domain) or ToUnicode(ToASCII(domain)). As a result, the + domain name returned within a userid on a GETATTR may not match that + sent when the userid is set using SETATTR, although when this + happens, the domain will be in the form of a U-label. When the + server does not map domain strings which are not U-labels into a + U-label, which it MAY do, it MUST NOT modify the domain and the + domain returned on a GETATTR of the userid MUST be the same as that + using when setting the userid by the SETATTTR. + + The server MAY implement VERIFY and NVERIFY without translating + internal state to a string form, so that, for example, a user + principal which represents a specific numeric user id, will match a + different principal string which represents the same numeric user id. + +12.7. String Types with NFS-specific Processing + + For a number of data types within NFSv4, the primary responsbibility + for internationalization-related handling is that of some entity + other than the server itself (see below for details). In these + situations, the primary responsibility of NFS version 4 is to provide + a framework in which that other entity (file system and server + operating system principal naming framework) to implement its own + decisions while establishing rules to limit interoperability issues. + + This pattern applies to the following data types: + + o In the case of name components (strings of type component4), the + server-side file system implementation (of which there may be more + than one for a particular server) deals with internationalization + issues, in a fashion that is appropriate to NFS version 4, other + remote file access protocols, and local file access methods. See + "Handling of File Came Components" for the detailed treatment. + + o In the case of link text strings (strings of type lintext4), the + issues are similar, but file systems are restricted in the set of + acceptable internationalization-related processing that they may + do, principally because symbolic links may contain name componetns + that, when used, are presented to other file systems and/or other + servers. See "Processing of Link Text" for the detailed + treatment. + + o In the case of principal prefix strings, any decisions regarding + internationalization are the responsibility of the server + operating systems which may make its own rules regarding user and + group name encoding. See "Processing of Principal Prefixes" for + the detailed treatment. + +12.7.1. Handling of File Came Components + + There are a number of places within client and server where file name + components are processed: + + o On the client, file names may be processed as part of forming NFS + version 4 requests. Any such processing will reflect specific + needs of the client's environment and will be treated as out-of- + scope from the viewpoint of this specification. + + o On the server, file names are processed as part of processing NFS + version 4 requests. In practice, parts of the processing will be + implemented within the NFS version 4 server while other parts will + be implemented within the file system. This processing is + described in the sections below. These sections are organized in + a fashion parallel to a stringprep profile. The same sorts of + topics are dealt with but they differ in that there is a wider + range of possible processing choices. + + o On the server, file name components might potentially be subject + to processing as part of generating NFS version 4 responses. This + specification assumes that this processing will be empty and that + file name components will be copied verbatim at this point. The + file name components may be modified as they appear in responses, + relative to the values used in the request but this is only + treated as reflecting changes made as part of request processing. + For example, a change to a file name component made in processing + a CREATE operation will be reflected in the READDIR since the + files created will have names that reflect CREATE-time processing. + + o On the client, responses will need to be properly dealt with and + the relevant issues will be discussed in the sections below. + Primarily, this will involve dealing with the fact that file name + components received in responses may need to be processed to meet + the requirements of the client's internal environment. This will + mainly involve dealing with changes in name components possibly + made by server processing. It also addresses other sorts of + expected behavior that do not involve a returned component4, such + as whether a LOOKUP finds a given component4 or whether a CREATE + or OPEN finds that a specified name already exists. + +12.7.1.1. Nature of Server Processing of Name Components in Request + + The component4 type defines a potentially case sensitive string, + typically of UTF-8 characters. Its use in NFS version 4 is for + representing file name components. Since file systems can implement + case insensitive file name handling, it can be used for both case + sensitive and case insensitive file name handling, based on the + attributes of the file system. + + It may be the case that two valid distinct UTF-8 strings will be the + same after the processing described below. In such a case, a server + may either, + + o disallow the creation of a second name if its post-processed form collides with that of an existing name, or o allow the creation of the second name, but arrange so that after - post processing, the second name is different than the post + post processing, the second name is different than the post- processed form of the first name. -11.1.2. Character repertoire of nfs4_cs_prep +12.7.1.2. Character Repertoire for the Component4 Type - The nfs4_cs_prep profile uses Unicode 3.2, as defined in stringprep's - Appendix A.1 + The RECOMMENDED character repertoire for file name components is a + recent/current version of Unicode, as encoded via UTF-8. There are a + number of alternate character repertoires which may be chosen by the + server based on implementation constraints including the requirements + of the file system being accessed. -11.1.3. Mapping used by nfs4_cs_prep + Two important alternative repertoires are: - The nfs4_cs_prep profile specifies mapping using the following tables - from stringprep: + o One alternate character repertoire is to represent file name + components as strings of bytes with no protocol-defined encoding + of multi-byte characters. Most typically, implementations that + support this single-byte alternative will make it available as an + option set by an administrator for all file systems within a + server or for some particular file systems. If a server accepts + non-UTF-8 strings anywhere within a specific file system, then it + MUST do so throughout the entire file system. - o Table B.1 + o Another alternate character repertoires is the set of codepoints, + representable by the file system, most typically UCS-4. - Table B.2 is normally not part of the nfs4_cs_prep profile as it is - primarily for dealing with case-insensitive comparisons. However, if - the NFS version 4 file server supports the case_insensitive - filesystem attribute, and if case_insensitive is true, the NFS - version 4 server MUST use Table B.2 (in addition to Table B1) when - processing utf8str_cs strings, and the NFS version 4 client MUST - assume Table B.2 (in addition to Table B.1) are being used. + Individual file system implementations may have more restricted + character repertoires, as for example file system that only are + capable of storing names consisting of UCS-2 characters. When this + is the case, and the character repertoire is not restricted to + single-byte characters, characters not within that repertoire are + treated as prohibited and the error NFS4ERR_BADCHAR is returned by + the server when that character is encountered. + + Strings are intended to be in UTF-8 format and servers SHOULD return + NFS4ERR_INVAL, as discussed above, when the characters sent are not + valid UTF-8. When the character repertoire consists of single-byte + characters, UTF-8 is not enforced. Such situations should be + restricted to those where use is within a restricted environment + where a single character mapping locale can be administratively + enforced, allowing a file name to be treated as string of bytes, + rather than as a string of characters. Such an arrangement might be + necessary when NFS version 4 access to a file system containing names + which are not valid UTF-8 needs to be provided. + + However, in any of the following situations, file names have to be + treated as strings of characters and servers MUST return + NFS4ERR_INVAL when file names that are not in UTF-8 format: + + o Case-insensitive comparisons are specified by the file system and + any characters sent contain non-ASCII byte codes. + + o Any normalization constraints are enforced by the server or file + system implementation. + + o The server accepts a given name when creating a file and reports a + different one when the directory is being examined. + + Much of the discussion below regarding normalization and silent + deletion of characters within component4 strings is not applicable + when the server does not enforce UTF-8 component4 strings and treats + them as strings of bytes. A client may determine that a given + filesystem is operating in this mode by performing a LOOKUP using a + non-UTF-8 string, if NFS4ERR_INVAL is not returned, then name + components will be treated as opaque and those sorts of modifications + will not be seen. + +12.7.1.3. Case-based Mapping Used for Component4 Strings + + Case-based mapping is not always a required part of server processing + of name components. However, if the NFS version 4 file server + supports the case_insensitive file system attribute, and if the + case_insensitive attribute is true for a given file system, the NFS + version 4 server must use the Unicode case mapping tables for the + version of Unicode corresponding to the character repertoire. In the + case where the character repertoire is UCS-2 or UCS-4, the case + mapping tables from the latest available version of Unicode should be + used. If the case_preserving attribute is present and set to false, then - the NFS version 4 server MUST use table B.2 to map case when - processing utf8str_cs strings. Whether the server maps from lower to - upper case or the upper to lower case is an implementation - dependency. + the NFS version 4 server MUST use the corresponding Unicode case + mapping table to map case when processing component4 strings. + Whether the server maps from lower to upper case or the upper to + lower case is a matter for implementation choice. -11.1.4. Normalization used by nfs4_cs_prep + Stringprep Table B.2 should not be used for these purpose since it is + limited to Unicode version 3.2 and also because it erroneously maps + the German ligature eszett to the string "ss", whereas later versions + of Unicode contain both lower-case and upper-case versions of Eszett + (SMALL LETTER SHARP S and CAPITAL LETTER SHARP S). - The nfs4_cs_prep profile does not specify a normalization form. A - later revision of this specification may specify a particular - normalization form. Therefore, the server and client can expect that - they may receive unnormalized characters within protocol requests and - responses. If the operating environment requires normalization, then - the implementation must normalize utf8str_cs strings within the - protocol before presenting the information to an application (at the - client) or local filesystem (at the server). + Clients should be aware that servers may have mapped SMALL LETTER + SHARP S to the string "ss" when case-insensitive mapping is in + effect, with result that file whose name contains SMALL LETTER SHARP + S may have that character replaced by "ss" or "SS". -11.1.5. Prohibited output for nfs4_cs_prep +12.7.1.4. Other Mapping Used for Component4 Strings - The nfs4_cs_prep profile specifies prohibiting using the following - tables from stringprep: + Other than for issues of case mapping, an NFS version 4 server SHOULD + limit visible (i.e. those that change the name of file to reflect + those mappings to those from from a subset of the stringprep table + B.1. Note particularly, the mapings from U+200C and U+200D to the + empty string should be avoided, due to their undesirable effect on + some strings in Farsi. - o Table C.3 + Table B.1 may be used but it should be used only if required by the + local file system implementation. For example, if the file system in + question accepts file names containing the MONGOLIAN TODO SOFT HYPHEN + character (U+1806) and they are distinct from the corresponding file + names with this character removed, then using Table B.1 will cause + functional problems when clients attempt to interact with that file + system. The NFS version 4 server implementation including the + filesystem MUST NOT silently remove characters not within Table B.1. - o Table C.4 + If an implementation wishes to eliminate other characters because it + is believed that allowing component name versions that both include + the character and not have while otherwise the same, will contribute + to confusion, it has two options: - o Table C.5 + o Treat the characters as prohibited and return NFS4ERR_BADCHAR. - o Table C.6 + o Eliminate the character as part of the name matching processing, + while retaining it when a file is created. This would be + analogous to file systems that are both case-insensitive and case- + preserving,as dicussed above, or those which are both + normalization-insensitive and normalization-preserving, as + discussed below. The handling will be insensitive to presence of + the chosen characters while preserving the presence or absence of + such chatacters within names. - o Table C.7 + Note that the second of these choices is a desirable way to handle + characters within table B.1, again with the exception of U+200C and + U+200D, which can cause issues for Farsi. - o Table C.8 + In addition to modification due to normalization, discussed below, + clients have to be able to deal with name modifications and other + consequences of character mapping on the server, as discussed above. - o Table C.9 +12.7.1.5. Normalization Issues for Component Strings -11.1.6. Bidirectional output for nfs4_cs_prep + The issues are best discussed separately for the server and the + client. It is important to note that the server and client may have + different approaches to this area, and that the server choice may not + match the client operating environment so the issue of mismatches and + how they will be dealt with by the client is discussed in a later + section. - The nfs4_cs_prep profile does not specify any checking of - bidirectional strings. +12.7.1.5.1. Server Normalization Issues for Component Strings -11.2. Stringprep profile for the utf8str_cis type + The NFS version 4 does not specify required use of a particular + normalization form for component4 strings. Therefore, the server may + receive unnormalized strings or strings that reflect either + normalization form within protocol requests and responses. If the + operating environment requires normalization, then the server + implementation must normalize component4 strings within the protocol + server before presenting the information to the local file system. - Every use of the utf8str_cis type definition in the NFS version 4 - protocol specification follows the profile named nfs4_cis_prep. + With regard to normalization, servers have the following choices, + with the possibility that different choices may be selected for + different file systems. -11.2.1. Intended applicability of the nfs4_cis_prep profile + o Implement a particular normalization form, either NFC, or NFD, in + which case file names received from a client are converted to that + normalization form and as a consequence, the client will always + receive names in that normalization form. If this option is + chosen, then it is impossible to create two files in the same + directory that have different names which map to the same name + when normalized. - The utf8str_cis type is a case insensitive string of UTF-8 - characters. Its primary use in NFS Version 4 is for naming NFS - servers. + o Implement handling which is both normalization-insensitive and + normalization-preserving. This makes it impossible to create two + files in the same directory that have two different canonically + equivalent name, i.e. names which map to the same name when + normalized. However, unlike the previous option, clients will not + have the names that they present modified to meet the server's + normalization constraints. -11.2.2. Character repertoire of nfs4_cis_prep + o Implement normalization-sensitive handling without enforcing a + normalization form constraint on file names. This exposes the + client to the possibility that two files can be created in the + same directory which have different names which map to the same + name when normalized. This may be a significant issue when client + which use different normalization forms are used on the same file + system, but this issue needs to be set against the difficulty of + providing other sorts of normalization handling for some existing + file systems. - The nfs4_cis_prep profile uses Unicode 3.2, as defined in - stringprep's Appendix A.1 +12.7.1.5.2. Client Normalization Issues for Component Strings -11.2.3. Mapping used by nfs4_cis_prep + The client, in processing name components, needs to deal with the + fact that the server may impose normalization on file name components + presented to it. As a result, a file can be created within a + directory and that name may have different name due to normalization + at the server. - The nfs4_cis_prep profile specifies mapping using the following - tables from stringprep: + Client operating environments differ in their handling of canonically + equivalent name. Some environments treat canonically equivalent + strings as essentially equal and we will call these environments + normalization-aware. Others, because of the pattern of their + development with regard to these issues treat different strings as + different, even if they are canonically equivalent. We call these + normalization-unaware. - o Table B.1 + Normalization-aware environments interoperate most normally with + servers that either impose a given normalization form or those that + implement name handling which is both normalization-insensitive and + normalization-preserving name handling. However, clients need to be + prepared to interoperate with servers that have normalization- + sensitive file naming. In this situation, the client needs to be + prepared for the fact that a directory may contain multiple names + that it considers equivalent. - o Table B.2 + Normalization-unaware environments interoperate most normally with + servers that implement normalization-sensitive file naming. However, + clients need to be prepared to interoperate with servers that impose + a given normalization form or that implement name handling which is + both normalization-insensitive and normalization-preserving. In the + former case, a file created with a given name may find it changed to + a different (although related name). In both cases, the client will + have to deal with the fact that it is unable to create two names + within a directory that are canonically equivalent. -11.2.4. Normalization used by nfs4_cis_prep +12.7.1.6. Prohibited Characters for Component Names - The nfs4_cis_prep profile specifies using Unicode normalization form - KC, as described in stringprep. + The NFS version 4 protocol does not specify particular characters + that may not appear in component names. File systems may have their + own set of prohibited characters for which the error NFS4ERR_BADCHAR + should be returned by the server. Clients need to be prepared for + this error to occur whenever file name components are presented to + the server. -11.2.5. Prohibited output for nfs4_cis_prep + Clients whose character repertoire for acceptable characters in file + name components is smaller than the entire scope of UCS-4 may need to + deal with names returned by the server that contain characters + outside that repertoire. It is up to the client whether it simply + ignores these files or modifies the name to meet its own rules for + acceptable names. - The nfs4_cis_prep profile specifies prohibiting using the following - tables from stringprep: + Clients may encounter names that do not consist of valid UTF-8, if + they interact with servers configured to allow this option. They are + not required to deal with this case and may treat the server as not + functioning correctly, or they may handle this as normal. Clients + will normally make this a configuration option. As discussed above, + a client can determine whether a particular file system is being + supported by the server in this mode by issuing a LOOKUP specifying a + name which is not valid UTF-8 and seeing if NFS4ERR_INVAL is + returned. - o Table C.1.2 +12.7.1.7. Bidirectional String Checking for Component Names - o Table C.2.2 + The NFS version 4 protocol does not require processing of component + names to check for and reject bidirectional strings. Such processing + may be a part of the file system implementation but if so, its + particular form will be defined by the file system implementation. + When strings are rejected on this basis, the error NFS4ERR_BADNAME + would be returned. - o Table C.3 + Clients need to be prepared for the fact that the server may reject a + file name component if it consists of a bidirectional string, + returning NFS4ERR_BADNAME. - o Table C.4 + Clients may encounter names with bidirectional strings returned in + responses from the server. If clients treat such strings as not + valid file name components, it is up to the client whether it simply + ignores these files or modifies the name component to meet its own + rules for acceptable name component strings. - o Table C.5 +12.7.2. Processing of Link Text - o Table C.6 + Symbolic link text is defined as utf8_should and therefore the server + SHOULD validate link text on a CREATE and return NFS4ERR_INVAL if it + is is not valid UTF-8. Note that file systems which treat names as + strings of byte are an exception for which such validation need not + be done. One other situation in which an NFS version 4 might choose + (or be configured) not to make such a check is when links within file + system reference names in another which is configured to treat names + as strings of bytes. - o Table C.7 + On the other hand, UTF-8 validation of symbolic link text need not be + done on the data resulting from a READLINK. Such data might have + been stored by an NFS Version 4 server configured to allow non-UTF-8 + link text or it might have resulted from symbolic link text stored + via local file system access or access via another remote file access + protocol. - o Table C.8 + Note that because of the role of the symbolic link, as data stored + and read by the user, other sorts of validations or modifications + should not be done. Note that when component names with the symbolic + link text are used, such checks and modifications will be done at + that time. In particular, - o Table C.9 + o Limitation of the character repertoire MUST NOT be done. This + includes limitations to reflect a particular version of unicode, + or the inability of any particualr file system to store characters + beyond UCS-2. -11.2.6. Bidirectional output for nfs4_cis_prep + o Name mapping, whether for case folding or otherwise MUST NOT be + done. - The nfs4_cis_prep profile specifies checking bidirectional strings as - described in stringprep's section 6. + o Checks for a type of normalization or normalization to a + particular form MUST NOT be done. -11.3. Stringprep profile for the utf8str_mixed type + o Checks for specific characters excluded by the server or file + system MUST NOT be done. - Every use of the utf8str_mixed type definition in the NFS version 4 - protocol specification follows the profile named nfs4_mixed_prep. + o Checks for bidrectional strings MUST NOT be done. -11.3.1. Intended applicability of the nfs4_mixed_prep profile +12.7.3. Processing of Principal Prefixes - The utf8str_mixed type is a string of UTF-8 characters, with a prefix - that is case sensitive, a separator equal to '@', and a suffix that - is fully qualified domain name. Its primary use in NFS Version 4 is - for naming principals identified in an Access Control Entry. + As mentioned above, users and groups are designated as a particular + string at a specified domain. Servers will recognize a set of valid + principals for one or more domains. With regard to the handling of + these strings, the following rules MUST be followed -11.3.2. Character repertoire of nfs4_mixed_prep + o The string MUST be checked by the server for valid UTF-8 and the + error NFS4ERR_INVAL returned if it is not valid. - The nfs4_mixed_prep profile uses Unicode 3.2, as defined in - stringprep's Appendix A.1 + o The character repertoire for the principal prefix string should be + limited to a current version of Unicode when the server is + implemented. However, the client cannot be assured that all + characters it receives as part of a user or group attribute are + those that are defined in the Unicode version it expects to work + with. -11.3.3. Mapping used by nfs4_cis_prep + o No character mapping is to be done, as for example table B.1 in + stringprep, and no case mapping is to be done. The user and group + names are to be treated as case-sensitive. - For the prefix and the separator of a utf8str_mixed string, the - nfs4_mixed_prep profile specifies mapping using the following table - from stringprep: + o Strings must not be rejected based on their normalization. + Servers should do normalization insensitive matching in converting + a user to group to an internal id. The client cannot assume that + the server preserves normalization so a user set to one string + value may be returned as a string which differs in nomralization + and the client must be prepared to deal with that, by, for + example, normalizing the string to the client's prferred form. - o Table B.1 + o There are no checks for specific invalid characters but servers + may limit the characters, with the result that any principal + presented by the client which has such a characters is treated as + invalid. - For the suffix of a utf8str_mixed string, the nfs4_mixed_prep profile - specifies mapping using the following tables from stringprep: + o Specific checks for bidrectional strings are not done but servers + may limit the principal prefix strings to those which are + unidirectional or are of a certain direction, with the result that + any principal presented by the client which done not meet that + criterion will be treated as invaid. - o Table B.1 +13. Error Values - o Table B.2 + NFS error numbers are assigned to failed operations within a Compound + (COMPOUND or CB_COMPOUND) request. A Compound request contains a + number of NFS operations that have their results encoded in sequence + in a Compound reply. The results of successful operations will + consist of an NFS4_OK status followed by the encoded results of the + operation. If an NFS operation fails, an error status will be + entered in the reply and the Compound request will be terminated. -11.3.4. Normalization used by nfs4_mixed_prep +13.1. Error Definitions - The nfs4_mixed_prep profile specifies using Unicode normalization - form KC, as described in stringprep. + Protocol Error Definitions -11.3.5. Prohibited output for nfs4_mixed_prep + +-----------------------------+--------+-------------------+ + | Error | Number | Description | + +-----------------------------+--------+-------------------+ + | NFS4_OK | 0 | Section 13.1.3.1 | + | NFS4ERR_ACCESS | 13 | Section 13.1.6.1 | + | NFS4ERR_ATTRNOTSUPP | 10032 | Section 13.1.11.1 | + | NFS4ERR_ADMIN_REVOKED | 10047 | Section 13.1.5.1 | + | NFS4ERR_BADCHAR | 10040 | Section 13.1.7.1 | + | NFS4ERR_BADHANDLE | 10001 | Section 13.1.2.1 | + | NFS4ERR_BADNAME | 10041 | Section 13.1.7.2 | + | NFS4ERR_BADOWNER | 10039 | Section 13.1.11.2 | + | NFS4ERR_BADTYPE | 10007 | Section 13.1.4.1 | + | NFS4ERR_BADXDR | 10036 | Section 13.1.1.1 | + | NFS4ERR_BAD_COOKIE | 10003 | Section 13.1.1.2 | + | NFS4ERR_BAD_RANGE | 10042 | Section 13.1.8.1 | + | NFS4ERR_BAD_SEQID | 10026 | Section 13.1.8.2 | + | NFS4ERR_BAD_STATEID | 10025 | Section 13.1.5.2 | + | NFS4ERR_CLID_INUSE | 10017 | Section 13.1.10.1 | + | NFS4ERR_DEADLOCK | 10045 | Section 13.1.8.3 | + | NFS4ERR_DELAY | 10008 | Section 13.1.1.3 | + | NFS4ERR_DENIED | 10010 | Section 13.1.8.4 | + | NFS4ERR_DQUOT | 69 | Section 13.1.4.2 | + | NFS4ERR_EXIST | 17 | Section 13.1.4.3 | + | NFS4ERR_EXPIRED | 10011 | Section 13.1.5.3 | + | NFS4ERR_FBIG | 27 | Section 13.1.4.4 | + | NFS4ERR_FHEXPIRED | 10014 | Section 13.1.2.2 | + | NFS4ERR_FILE_OPEN | 10046 | Section 13.1.4.5 | + | NFS4ERR_GRACE | 10013 | Section 13.1.9.1 | + | NFS4ERR_INVAL | 22 | Section 13.1.1.4 | + | NFS4ERR_IO | 5 | Section 13.1.4.6 | + | NFS4ERR_ISDIR | 21 | Section 13.1.2.3 | + | NFS4ERR_LEASE_MOVED | 10031 | Section 13.1.5.4 | + | NFS4ERR_LOCKED | 10012 | Section 13.1.8.5 | + | NFS4ERR_LOCKS_HELD | 10037 | Section 13.1.8.6 | + | NFS4ERR_LOCK_NOTSUPP | 10043 | Section 13.1.8.7 | + | NFS4ERR_LOCK_RANGE | 10028 | Section 13.1.8.8 | + | NFS4ERR_MINOR_VERS_MISMATCH | 10021 | Section 13.1.3.2 | + | NFS4ERR_MLINK | 31 | Section 13.1.4.7 | + | NFS4ERR_MOVED | 10019 | Section 13.1.2.4 | + | NFS4ERR_NAMETOOLONG | 63 | Section 13.1.7.3 | + | NFS4ERR_NOENT | 2 | Section 13.1.4.8 | + | NFS4ERR_NOFILEHANDLE | 10020 | Section 13.1.2.5 | + | NFS4ERR_NOSPC | 28 | Section 13.1.4.9 | + | NFS4ERR_NOTDIR | 20 | Section 13.1.2.6 | + | NFS4ERR_NOTEMPTY | 66 | Section 13.1.4.10 | + | NFS4ERR_NOTSUPP | 10004 | Section 13.1.1.5 | + | NFS4ERR_NOT_SAME | 10027 | Section 13.1.11.3 | + | NFS4ERR_NO_GRACE | 10033 | Section 13.1.9.2 | + | NFS4ERR_NXIO | 6 | Section 13.1.4.11 | + | NFS4ERR_OLD_STATEID | 10024 | Section 13.1.5.5 | + | NFS4ERR_OPENMODE | 10038 | Section 13.1.8.9 | + | NFS4ERR_OP_ILLEGAL | 10044 | Section 13.1.3.3 | + | NFS4ERR_PERM | 1 | Section 13.1.6.2 | + | NFS4ERR_RECLAIM_BAD | 10034 | Section 13.1.9.3 | + | NFS4ERR_RECLAIM_CONFLICT | 10035 | Section 13.1.9.4 | + | NFS4ERR_RESOURCE | 10018 | Section 13.1.3.4 | + | NFS4ERR_RESTOREFH | 10030 | Section 13.1.4.12 | + | NFS4ERR_ROFS | 30 | Section 13.1.4.13 | + | NFS4ERR_SAME | 10009 | Section 13.1.11.4 | + | NFS4ERR_SERVERFAULT | 10006 | Section 13.1.1.6 | + | NFS4ERR_STALE | 70 | Section 13.1.2.7 | + | NFS4ERR_STALE_CLIENTID | 10022 | Section 13.1.10.2 | + | NFS4ERR_STALE_STATEID | 10023 | Section 13.1.5.6 | + | NFS4ERR_SYMLINK | 10029 | Section 13.1.2.8 | + | NFS4ERR_TOOSMALL | 10005 | Section 13.1.1.7 | + | NFS4ERR_WRONGSEC | 10016 | Section 13.1.6.3 | + | NFS4ERR_XDEV | 18 | Section 13.1.4.14 | + +-----------------------------+--------+-------------------+ - The nfs4_mixed_prep profile specifies prohibiting using the following - tables from stringprep: + Table 8 - o Table C.1.2 +13.1.1. General Errors - o Table C.2.2 + This section deals with errors that are applicable to a broad set of + different purposes. - o Table C.3 +13.1.1.1. NFS4ERR_BADXDR (Error Code 10036) - o Table C.4 + The arguments for this operation do not match those specified in the + XDR definition. This includes situations in which the request ends + before all the arguments have been seen. Note that this error + applies when fixed enumerations (these include booleans) have a value + within the input stream which is not valid for the enum. A replier + may pre-parse all operations for a Compound procedure before doing + any operation execution and return RPC-level XDR errors in that case. - o Table C.5 +13.1.1.2. NFS4ERR_BAD_COOKIE (Error Code 10003) - o Table C.6 + Used for operations that provide a set of information indexed by some + quantity provided by the client or cookie sent by the server for an + earlier invocation. Where the value cannot be used for its intended + purpose, this error results. - o Table C.7 +13.1.1.3. NFS4ERR_DELAY (Error Code 10008) - o Table C.8 + For any of a number of reasons, the replier could not process this + operation in what was deemed a reasonable time. The client should + wait and then try the request with a new RPC transaction ID. - o Table C.9 + Some example of situations that might lead to this situation: -11.3.6. Bidirectional output for nfs4_mixed_prep + o A server that supports hierarchical storage receives a request to + process a file that had been migrated. - The nfs4_mixed_prep profile specifies checking bidirectional strings - as described in stringprep's section 6. + o An operation requires a delegation recall to proceed and waiting + for this delegation recall makes processing this request in a + timely fashion impossible. -11.4. UTF-8 Related Errors + In such cases, the error NFS4ERR_DELAY allows these preparatory + operations to proceed without holding up client resources such as a + session slot. After delaying for period of time, the client can then + re-send the operation in question. - Where the client sends an invalid UTF-8 string, the server should - return an NFS4ERR_INVAL error. This includes cases in which - inappropriate prefixes are detected and where the count includes - trailing bytes that do not constitute a full UCS character. +13.1.1.4. NFS4ERR_INVAL (Error Code 22) - Where the client supplied string is valid UTF-8 but contains - characters that are not supported by the server as a value for that - string (e.g., names containing characters that have more than two - octets on a filesystem that supports Unicode characters only), the - server should return an NFS4ERR_BADCHAR error. + The arguments for this operation are not valid for some reason, even + though they do match those specified in the XDR definition for the + request. - Where a UTF-8 string is used as a file name, and the filesystem, - while supporting all of the characters within the name, does not - allow that particular name to be used, the server should return the - error NFS4ERR_BADNAME. This includes situations in which the server - filesystem imposes a normalization constraint on name strings, but - will also include such situations as filesystem prohibitions of "." - and ".." as file names for certain operations, and other such - constraints. +13.1.1.5. NFS4ERR_NOTSUPP (Error Code 10004) -12. Error Definitions + Operation not supported, either because the operation is an OPTIONAL + one and is not supported by this server or because the operation MUST + NOT be implemented in the current minor version. - NFS error numbers are assigned to failed operations within a compound - request. A compound request contains a number of NFS operations that - have their results encoded in sequence in a compound reply. The - results of successful operations will consist of an NFS4_OK status - followed by the encoded results of the operation. If an NFS - operation fails, an error status will be entered in the reply and the - compound request will be terminated. +13.1.1.6. NFS4ERR_SERVERFAULT (Error Code 10006) - A description of each defined error follows: + An error occurred on the server which does not map to any of the + specific legal NFSv4.1 protocol error values. The client should + translate this into an appropriate error. UNIX clients may choose to + translate this to EIO. - NFS4_OK Indicates the operation completed successfully. +13.1.1.7. NFS4ERR_TOOSMALL (Error Code 10005) - NFS4ERR_ACCESS Permission denied. The caller does not have the - correct permission to perform the requested operation. Contrast - this with NFS4ERR_PERM, which restricts itself to owner or - privileged user permission failures. + Used where an operation returns a variable amount of data, with a + limit specified by the client. Where the data returned cannot be fit + within the limit specified by the client, this error results. - NFS4ERR_ATTRNOTSUPP An attribute specified is not supported by the - server. Does not apply to the GETATTR operation. +13.1.2. Filehandle Errors - NFS4ERR_ADMIN_REVOKED Due to administrator intervention, the - lockowner's record locks, share reservations, and delegations have - been revoked by the server. + These errors deal with the situation in which the current or saved + filehandle, or the filehandle passed to PUTFH intended to become the + current filehandle, is invalid in some way. This includes situations + in which the filehandle is a valid filehandle in general but is not + of the appropriate object type for the current operation. - NFS4ERR_BADCHAR A UTF-8 string contains a character which is not - supported by the server in the context in which it being used. + Where the error description indicates a problem with the current or + saved filehandle, it is to be understood that filehandles are only + checked for the condition if they are implicit arguments of the + operation in question. - NFS4ERR_BAD_COOKIE READDIR cookie is stale. +13.1.2.1. NFS4ERR_BADHANDLE (Error Code 10001) - NFS4ERR_BADHANDLE Illegal NFS filehandle. The filehandle failed - internal consistency checks. + Illegal NFS filehandle for the current server. The current file + handle failed internal consistency checks. Once accepted as valid + (by PUTFH), no subsequent status change can cause the filehandle to + generate this error. - NFS4ERR_BADNAME A name string in a request consists of valid UTF-8 - characters supported by the server but the name is not supported - by the server as a valid name for current operation. +13.1.2.2. NFS4ERR_FHEXPIRED (Error Code 10014) - NFS4ERR_BADOWNER An owner, owner_group, or ACL attribute value can - not be translated to local representation. + A current or saved filehandle which is an argument to the current + operation is volatile and has expired at the server. - NFS4ERR_BADTYPE An attempt was made to create an object of a type - not supported by the server. +13.1.2.3. NFS4ERR_ISDIR (Error Code 21) - NFS4ERR_BAD_RANGE The range for a LOCK, LOCKT, or LOCKU operation is - not appropriate to the allowable range of offsets for the server. + The current or saved filehandle designates a directory when the + current operation does not allow a directory to be accepted as the + target of this operation. - NFS4ERR_BAD_SEQID The sequence number in a locking request is - neither the next expected number or the last number processed. +13.1.2.4. NFS4ERR_MOVED (Error Code 10019) - NFS4ERR_BAD_STATEID A stateid generated by the current server - instance, but which does not designate any locking state (either - current or superseded) for a current lockowner-file pair, was - used. + The file system which contains the current filehandle object is not + present at the server. It may have been relocated, migrated to + another server or may have never been present. The client may obtain + the new file system location by obtaining the "fs_locations" or + attribute for the current filehandle. For further discussion, refer + to Section 7 - NFS4ERR_BADXDR The server encountered an XDR decoding error while - processing an operation. +13.1.2.5. NFS4ERR_NOFILEHANDLE (Error Code 10020) - NFS4ERR_CLID_INUSE The SETCLIENTID operation has found that a client - id is already in use by another client. + The logical current or saved filehandle value is required by the + current operation and is not set. This may be a result of a + malformed COMPOUND operation (i.e. no PUTFH or PUTROOTFH before an + operation that requires the current filehandle be set). - NFS4ERR_DEADLOCK The server has been able to determine a file - locking deadlock condition for a blocking lock request. +13.1.2.6. NFS4ERR_NOTDIR (Error Code 20) - NFS4ERR_DELAY The server initiated the request, but was not able to - complete it in a timely fashion. The client should wait and then - try the request with a new RPC transaction ID. For example, this - error should be returned from a server that supports hierarchical - storage and receives a request to process a file that has been - migrated. In this case, the server should start the immigration - process and respond to client with this error. This error may - also occur when a necessary delegation recall makes processing a - request in a timely fashion impossible. + The current (or saved) filehandle designates an object which is not a + directory for an operation in which a directory is required. - NFS4ERR_DENIED An attempt to lock a file is denied. Since this may - be a temporary condition, the client is encouraged to retry the - lock request until the lock is accepted. +13.1.2.7. NFS4ERR_STALE (Error Code 70) - NFS4ERR_DQUOT Resource (quota) hard limit exceeded. The user's - resource limit on the server has been exceeded. + The current or saved filehandle value designating an argument to the + current operation is invalid The file referred to by that filehandle + no longer exists or access to it has been revoked. - NFS4ERR_EXIST File exists. The file specified already exists. +13.1.2.8. NFS4ERR_SYMLINK (Error Code 10029) - NFS4ERR_EXPIRED A lease has expired that is being used in the - current operation. + The current filehandle designates a symbolic link when the current + operation does not allow a symbolic link as the target. - NFS4ERR_FBIG File too large. The operation would have caused a file - to grow beyond the server's limit. +13.1.3. Compound Structure Errors - NFS4ERR_FHEXPIRED The filehandle provided is volatile and has - expired at the server. + This section deals with errors that relate to overall structure of a + Compound request (by which we mean to include both COMPOUND and + CB_COMPOUND), rather than to particular operations. - NFS4ERR_FILE_OPEN The operation can not be successfully processed - because a file involved in the operation is currently open. + There are a number of basic constraints on the operations that may + appear in a Compound request. - NFS4ERR_GRACE The server is in its recovery or grace period which - should match the lease period of the server. +13.1.3.1. NFS_OK (Error code 0) - NFS4ERR_INVAL Invalid argument or unsupported argument for an - operation. Two examples are attempting a READLINK on an object - other than a symbolic link or specifying a value for an enum field - that is not defined in the protocol (e.g., nfs_ftype4). + Indicates the operation completed successfully, in that all of the + constituent operations completed without error. - NFS4ERR_IO I/O error. A hard error (for example, a disk error) - occurred while processing the requested operation. +13.1.3.2. NFS4ERR_MINOR_VERS_MISMATCH (Error code 10021) - NFS4ERR_ISDIR Is a directory. The caller specified a directory in a - non-directory operation. + The minor version specified is not one that the current listener + supports. This value is returned in the overall status for the + Compound but is not associated with a specific operation since the + results must specify a result count of zero. - NFS4ERR_LEASE_MOVED A lease being renewed is associated with a - filesystem that has been migrated to a new server. +13.1.3.3. NFS4ERR_OP_ILLEGAL (Error Code 10044) - NFS4ERR_LOCKE A read or write operation was attempted on a locked - file. + The operation code is not a valid one for the current Compound + procedure. The opcode in the result stream matched with this error + is the ILLEGAL value, although the value that appears in the request + stream may be different. Where an illegal value appears and the + replier pre-parses all operations for a Compound procedure before + doing any operation execution, an RPC-level XDR error may be returned + in this case. - NFS4ERR_LOCK_NOTSUPP Server does not support atomic upgrade or - downgrade of locks. +13.1.3.4. NFS4ERR_RESOURCE (Error Code 10018) - NFS4ERR_LOCK_RANGE A lock request is operating on a sub-range of a - current lock for the lock owner and the server does not support - this type of request. + For the processing of the Compound procedure, the server may exhaust + available resources and can not continue processing operations within + the Compound procedure. This error will be returned from the server + in those instances of resource exhaustion related to the processing + of the Compound procedure. - NFS4ERR_LOCKS_HELD A CLOSE was attempted and file locks would exist - after the CLOSE. +13.1.4. File System Errors - NFS4ERR_MINOR_VERS_MISMATCH The server has received a request that - specifies an unsupported minor version. The server must return a - COMPOUND4res with a zero length operations result array. + These errors describe situations which occurred in the underlying + file system implementation rather than in the protocol or any NFSv4.x + feature. - NFS4ERR_MLINK Too many hard links. +13.1.4.1. NFS4ERR_BADTYPE (Error Code 10007) - NFS4ERR_MOVED The filesystem which contains the current filehandle - object has been relocated or migrated to another server. The - client may obtain the new filesystem location by obtaining the - "fs_locations" attribute for the current filehandle. For further - discussion, refer to the section "Filesystem Migration or - Relocation". + An attempt was made to create an object with an inappropriate type + specified to CREATE. This may be because the type is undefined, + because it is a type not supported by the server, or because it is a + type for which create is not intended such as a regular file or named + attribute, for which OPEN is used to do the file creation. - NFS4ERR_NAMETOOLONG The filename in an operation was too long. +13.1.4.2. NFS4ERR_DQUOT (Error Code 19) - NFS4ERR_NOENT No such file or directory. The file or directory name - specified does not exist. + Resource (quota) hard limit exceeded. The user's resource limit on + the server has been exceeded. - NFS4ERR_NOFILEHANDLE The logical current filehandle value (or, in - the case of RESTOREFH, the saved filehandle value) has not been - set properly. This may be a result of a malformed COMPOUND - operation (i.e., no PUTFH or PUTROOTFH before an operation that - requires the current filehandle be set). +13.1.4.3. NFS4ERR_EXIST (Error Code 17) - NFS4ERR_NO_GRACE A reclaim of client state has fallen outside of the - grace period of the server. As a result, the server can not - guarantee that conflicting state has not been provided to another - client. + A file of the specified target name (when creating, renaming or + linking) already exists. - NFS4ERR_NOSPC No space left on device. The operation would have - caused the server's filesystem to exceed its limit. +13.1.4.4. NFS4ERR_FBIG (Error Code 27) - NFS4ERR_NOTDIR Not a directory. The caller specified a non- - directory in a directory operation. + File too large. The operation would have caused a file to grow + beyond the server's limit. - NFS4ERR_NOTEMPTY An attempt was made to remove a directory that was - not empty. +13.1.4.5. NFS4ERR_FILE_OPEN (Error Code 10046) - NFS4ERR_NOTSUPP Operation is not supported. + The operation is not allowed because a file involved in the operation + is currently open. Servers may, but are not required to disallow + linking-to, removing, or renaming open files. - NFS4ERR_NOT_SAME This error is returned by the VERIFY operation to - signify that the attributes compared were not the same as provided - in the client's request. +13.1.4.6. NFS4ERR_IO (Error Code 5) - NFS4ERR_NXIO I/O error. No such device or address. + Indicates that an I/O error occurred for which the file system was + unable to provide recovery. - NFS4ERR_OLD_STATEID A stateid which designates the locking state for - a lockowner-file at an earlier time was used. +13.1.4.7. NFS4ERR_MLINK (Error Code 31) - NFS4ERR_OPENMODE The client attempted a READ, WRITE, LOCK or SETATTR - operation not sanctioned by the stateid passed (e.g., writing to a - file opened only for read). + The request would have caused the server's limit for the number of + hard links a file may have to be exceeded. - NFS4ERR_OP_ILLEGAL An illegal operation value has been specified in - the argop field of a COMPOUND or CB_COMPOUND procedure. +13.1.4.8. NFS4ERR_NOENT (Error Code 2) - NFS4ERR_PERM Not owner. The operation was not allowed because the - caller is either not a privileged user (root) or not the owner of - the target of the operation. + Indicates no such file or directory. The file or directory name + specified does not exist. - NFS4ERR_RECLAIM_BAD The reclaim provided by the client does not - match any of the server's state consistency checks and is bad. +13.1.4.9. NFS4ERR_NOSPC (Error Code 28) - NFS4ERR_RECLAIM_CONFLICT The reclaim provided by the client has - encountered a conflict and can not be provided. Potentially - indicates a misbehaving client. + Indicates no space left on device. The operation would have caused + the server's file system to exceed its limit. - NFS4ERR_RESOURCE For the processing of the COMPOUND procedure, the - server may exhaust available resources and can not continue - processing operations within the COMPOUND procedure. This error - will be returned from the server in those instances of resource - exhaustion related to the processing of the COMPOUND procedure. +13.1.4.10. NFS4ERR_NOTEMPTY (Error Code 66) - NFS4ERR_RESTOREFH The RESTOREFH operation does not have a saved - filehandle (identified by SAVEFH) to operate upon. + An attempt was made to remove a directory that was not empty. - NFS4ERR_ROFS Read-only filesystem. A modifying operation was +13.1.4.11. NFS4ERR_NXIO (Error Code 5) + + I/O error. No such device or address. + +13.1.4.12. NFS4ERR_RESTOREFH (Error Code 10030) + + The RESTOREFH operation does not have a saved filehandle (identified + by SAVEFH) to operate upon. + +13.1.4.13. NFS4ERR_ROFS (Error Code 30) + + Indicates a read-only file system. A modifying operation was attempted on a read-only filesystem. - NFS4ERR_SAME This error is returned by the NVERIFY operation to - signify that the attributes compared were the same as provided in - the client's request. +13.1.4.14. NFS4ERR_XDEV (Error Code 18) - NFS4ERR_SERVERFAULT An error occurred on the server which does not - map to any of the legal NFS version 4 protocol error values. The - client should translate this into an appropriate error. UNIX - clients may choose to translate this to EIO. + Indicates an attempt to do an operation, such as linking, that + inappropriately crosses a boundary. This may be due to such + boundaries as: - NFS4ERR_SHARE_DENIED An attempt to OPEN a file with a share - reservation has failed because of a share conflict. + o That between file systems (where the fsids are different). - NFS4ERR_STALE Invalid filehandle. The filehandle given in the - arguments was invalid. The file referred to by that filehandle no - longer exists or access to it has been revoked. + o That between different named attribute directories or between a + named attribute directory and an ordinary directory. - NFS4ERR_STALE_CLIENTID A clientid not recognized by the server was - used in a locking or SETCLIENTID_CONFIRM request. + o That between regions of a file system that the file system + implementation treats as separate (for example for space + accounting purposes), and where cross-connection between the + regions are not allowed. - NFS4ERR_STALE_STATEID A stateid generated by an earlier server - instance was used. +13.1.5. State Management Errors - NFS4ERR_SYMLINK The current filehandle provided for a LOOKUP is not - a directory but a symbolic link. Also used if the final component - of the OPEN path is a symbolic link. + These errors indicate problems with the stateid (or one of the + stateids) passed to a given operation. This includes situations in + which the stateid is invalid as well as situations in which the + stateid is valid but designates revoked locking state. Depending on + the operation, the stateid when valid may designate opens, byte-range + locks, file or directory delegations, layouts, or device maps. - NFS4ERR_TOOSMALL The encoded response to a READDIR request exceeds - the size limit set by the initial request. +13.1.5.1. NFS4ERR_ADMIN_REVOKED (Error Code 10047) - NFS4ERR_WRONGSEC The security mechanism being used by the client for + A stateid designates locking state of any type that has been revoked + due to administrative interaction, possibly while the lease is valid. + +13.1.5.2. NFS4ERR_BAD_STATEID (Error Code 10026) + + A stateid generated by the current server instance, but which does + not designate any locking state (either current or superseded) for a + current lockowner-file pair, was used. + +13.1.5.3. NFS4ERR_EXPIRED (Error Code 10011) + + A stateid designates locking state of any type that has been revoked + due to expiration of the client's lease, either immediately upon + lease expiration, or following a later request for a conflicting + lock. + +13.1.5.4. NFS4ERR_LEASE_MOVED (Error Code 10031) + + A lease being renewed is associated with a file system that has been + migrated to a new server. + +13.1.5.5. NFS4ERR_OLD_STATEID (Error Code 10024) + + A stateid with a non-zero seqid value does match the current seqid + for the state designated by the user. + +13.1.5.6. NFS4ERR_STALE_STATEID (Error Code 10023) + + A stateid generated by an earlier server instance was used. + +13.1.6. Security Errors + + These are the various permission-related errors in NFSv4.1. + +13.1.6.1. NFS4ERR_ACCESS (Error Code 13) + + Indicates permission denied. The caller does not have the correct + permission to perform the requested operation. Contrast this with + NFS4ERR_PERM (Section 13.1.6.2), which restricts itself to owner or + privileged user permission failures. + +13.1.6.2. NFS4ERR_PERM (Error Code 1) + + Indicates requester is not the owner. The operation was not allowed + because the caller is neither a privileged user (root) nor the owner + of the target of the operation. + +13.1.6.3. NFS4ERR_WRONGSEC (Error Code 10016) + + Indicates that the security mechanism being used by the client for the operation does not match the server's security policy. The - client should change the security mechanism being used and retry - the operation. + client should change the security mechanism being used and re-send + the operation. SECINFO can be used to determine the appropriate + mechanism. - NFS4ERR_XDEV Attempt to do an operation between different fsids. +13.1.7. Name Errors -13. NFS version 4 Requests + Names in NFSv4 are UTF-8 strings. When the strings are not are of + length zero, the error NFS4ERR_INVAL results. When they are not + valid UTF-8 the error NFS4ERR_INVAL also results, but servers may + accommodate file systems with different character formats and not + return this error. Besides this, there are a number of other errors + to indicate specific problems with names. + +13.1.7.1. NFS4ERR_BADCHAR (Error Code 10040) + + A UTF-8 string contains a character which is not supported by the + server in the context in which it being used. + +13.1.7.2. NFS4ERR_BADNAME (Error Code 10041) + + A name string in a request consisted of valid UTF-8 characters + supported by the server but the name is not supported by the server + as a valid name for current operation. An example might be creating + a file or directory named ".." on a server whose file system uses + that name for links to parent directories. + + This error should not be returned due a normalization issue in a + string. When a file system keeps names in a particular normalization + form, it is the server's responsiblity to do the approproriate + normalization, rather than rejecting the name. + +13.1.7.3. NFS4ERR_NAMETOOLONG (Error Code 63) + + Returned when the filename in an operation exceeds the server's + implementation limit. + +13.1.8. Locking Errors + + This section deal with errors related to locking, both as to share + reservations and byte-range locking. It does not deal with errors + specific to the process of reclaiming locks. Those are dealt with in + the next section. + +13.1.8.1. NFS4ERR_BAD_RANGE (Error Code 10042) + + The range for a LOCK, LOCKT, or LOCKU operation is not appropriate to + the allowable range of offsets for the server. E.g., this error + results when a server which only supports 32-bit ranges receives a + range that cannot be handled by that server. (See Section 15.12.4). + +13.1.8.2. NFS4ERR_BAD_SEQID (Error Code 10026) + + The sequence number (seqid) in a locking request is neither the next + expected number or the last number processed. + +13.1.8.3. NFS4ERR_DEADLOCK (Error Code 10045) + + The server has been able to determine a file locking deadlock + condition for a blocking lock request. + +13.1.8.4. NFS4ERR_DENIED (Error Code 10010) + + An attempt to lock a file is denied. Since this may be a temporary + condition, the client is encouraged to re-send the lock request until + the lock is accepted. See Section 9.4 for a discussion of the re- + send. + +13.1.8.5. NFS4ERR_LOCKED (Error Code 10012) + + A read or write operation was attempted on a file where there was a + conflict between the I/O and an existing lock: + + o There is a share reservation inconsistent with the I/O being done. + + o The range to be read or written intersects an existing mandatory + byte range lock. + +13.1.8.6. NFS4ERR_LOCKS_HELD (Error Code 10037) + + An operation was prevented by the unexpected presence of locks. + +13.1.8.7. NFS4ERR_LOCK_NOTSUPP (Error Code 10043) + + A locking request was attempted which would require the upgrade or + downgrade of a lock range already held by the owner when the server + does not support atomic upgrade or downgrade of locks. + +13.1.8.8. NFS4ERR_LOCK_RANGE (Error Code 10028) + + A lock request is operating on a range that overlaps in part a + currently held lock for the current lock owner and does not precisely + match a single such lock where the server does not support this type + of request, and thus does not implement POSIX locking semantics. See + Section 15.12.5, Section 15.13.5, and Section 15.14.5 for a + discussion of how this applies to LOCK, LOCKT, and LOCKU + respectively. + +13.1.8.9. NFS4ERR_OPENMODE (Error Code 10038) + + The client attempted a READ, WRITE, LOCK or other operation not + sanctioned by the stateid passed (e.g. writing to a file opened only + for read). + +13.1.9. Reclaim Errors + + These errors relate to the process of reclaiming locks after a server + restart. + +13.1.9.1. NFS4ERR_GRACE (Error Code 10013) + + The server is in its recovery or grace period which should at least + match the lease period of the server. A locking request other than a + reclaim could not be granted during that period. + +13.1.9.2. NFS4ERR_NO_GRACE (Error Code 10033) + + A reclaim of client state was attempted in circumstances in which the + server cannot guarantee that conflicting state has not been provided + to another client. As a result, the server can not guarantee that + conflicting state has not been provided to another client. + +13.1.9.3. NFS4ERR_RECLAIM_BAD (Error Code 10034) + + A reclaim attempted by the client does not match the server's state + consistency checks and has been rejected therefore as invalid. + +13.1.9.4. NFS4ERR_RECLAIM_CONFLICT (Error Code 10035) + + The reclaim attempted by the client has encountered a conflict and + cannot be satisfied. Potentially indicates a misbehaving client, + although not necessarily the one receiving the error. The + misbehavior might be on the part of the client that established the + lock with which this client conflicted. + +13.1.10. Client Management Errors + + This sections deals with errors associated with requests used to + create and manage client IDs. + +13.1.10.1. NFS4ERR_CLID_INUSE (Error Code 10017) + + The SETCLIENTID operation has found that a client id is already in + use by another client. + +13.1.10.2. NFS4ERR_STALE_CLIENTID (Error Code 10022) + + A clientid not recognized by the server was used in a locking or + SETCLIENTID_CONFIRM request. + +13.1.11. Attribute Handling Errors + + This section deals with errors specific to attribute handling within + NFSv4. + +13.1.11.1. NFS4ERR_ATTRNOTSUPP (Error Code 10032) + + An attribute specified is not supported by the server. This error + MUST NOT be returned by the GETATTR operation. + +13.1.11.2. NFS4ERR_BADOWNER (Error Code 10039) + + Returned when an owner or owner_group attribute value or the who + field of an ace within an ACL attribute value cannot be translated to + a local representation. + +13.1.11.3. NFS4ERR_NOT_SAME (Error Code 10027) + + This error is returned by the VERIFY operation to signify that the + attributes compared were not the same as those provided in the + client's request. + +13.1.11.4. NFS4ERR_SAME (Error Code 10009) + + This error is returned by the NVERIFY operation to signify that the + attributes compared were the same as those provided in the client's + request. + +13.2. Operations and their valid errors + + This section contains a table which gives the valid error returns for + each protocol operation. The error code NFS4_OK (indicating no + error) is not listed but should be understood to be returnable by all + operations except ILLEGAL. + + Valid error returns for each protocol operation + + +---------------------+---------------------------------------------+ + | Operation | Errors | + +---------------------+---------------------------------------------+ + | ACCESS | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_INVAL, | + | | NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | CLOSE | NFS4ERR_ADMIN_REVOKED, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BAD_SEQID, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_EXPIRED, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_ISDIR, | + | | NFS4ERR_LEASE_MOVED, NFS4ERR_LOCKS_HELD, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_OLD_STATEID, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_STALE_STATEID | + | COMMIT | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_ISDIR, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_RESOURCE, NFS4ERR_ROFS, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_SYMLINK | + | CREATE | NFS4ERR_ACCESS, NFS4ERR_ATTRNOTSUPP, | + | | NFS4ERR_BADCHAR, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADNAME, NFS4ERR_BADOWNER, | + | | NFS4ERR_BADTYPE, NFS4ERR_BADXDR, | + | | NFS4ERR_DELAY, NFS4ERR_DQUOT, | + | | NFS4ERR_EXIST, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NAMETOOLONG, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NOSPC, NFS4ERR_NOTDIR, | + | | NFS4ERR_PERM, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE | + | DELEGPURGE | NFS4ERR_BADXDR, NFS4ERR_NOTSUPP, | + | | NFS4ERR_LEASE_MOVED, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE_CLIENTID | + | DELEGRETURN | NFS4ERR_ADMIN_REVOKED, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_BADXDR, NFS4ERR_EXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NOTSUPP, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_STALE_STATEID | + | GETATTR | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | GETFH | NFS4ERR_BADHANDLE, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE | + | ILLEGAL | NFS4ERR_BADXDR, NFS4ERR_OP_ILLEGAL | + | LINK | NFS4ERR_ACCESS, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_DQUOT, NFS4ERR_EXIST, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_FILE_OPEN, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_ISDIR, | + | | NFS4ERR_MLINK, NFS4ERR_MOVED, | + | | NFS4ERR_NAMETOOLONG, NFS4ERR_NOENT, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOSPC, | + | | NFS4ERR_NOTDIR, NFS4ERR_NOTSUPP, | + | | NFS4ERR_RESOURCE, NFS4ERR_ROFS, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_WRONGSEC, NFS4ERR_XDEV | + | LOCK | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BAD_RANGE, | + | | NFS4ERR_BAD_SEQID, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_BADXDR, NFS4ERR_DEADLOCK, | + | | NFS4ERR_DELAY, NFS4ERR_DENIED, | + | | NFS4ERR_EXPIRED, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, | + | | NFS4ERR_ISDIR, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_LOCK_NOTSUPP, NFS4ERR_LOCK_RANGE, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NO_GRACE, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_OPENMODE, NFS4ERR_RECLAIM_BAD, | + | | NFS4ERR_RECLAIM_CONFLICT, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_STALE_CLIENTID, | + | | NFS4ERR_STALE_STATEID | + | LOCKT | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BAD_RANGE, NFS4ERR_BADXDR, | + | | NFS4ERR_DELAY, NFS4ERR_DENIED, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_ISDIR, | + | | NFS4ERR_LEASE_MOVED, NFS4ERR_LOCK_RANGE, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_STALE_CLIENTID | + | LOCKU | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BAD_RANGE, | + | | NFS4ERR_BAD_SEQID, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_BADXDR, NFS4ERR_EXPIRED, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_ISDIR, | + | | NFS4ERR_LEASE_MOVED, NFS4ERR_LOCK_RANGE, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_OLD_STATEID, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_STALE_STATEID | + | LOOKUP | NFS4ERR_ACCESS, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADXDR, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NAMETOOLONG, NFS4ERR_NOENT, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOTDIR, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_SYMLINK, | + | | NFS4ERR_WRONGSEC | + | LOOKUPP | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_DELAY, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_IO, NFS4ERR_MOVED, NFS4ERR_NOENT, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOTDIR, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_SYMLINK, | + | | NFS4ERR_WRONGSEC | + | NVERIFY | NFS4ERR_ACCESS, NFS4ERR_ATTRNOTSUPP, | + | | NFS4ERR_BADCHAR, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_SAME, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | OPEN | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_ATTRNOTSUPP, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADOWNER, NFS4ERR_BADXDR, | + | | NFS4ERR_BAD_SEQID, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_DELAY, NFS4ERR_DQUOT, | + | | NFS4ERR_EXIST, NFS4ERR_EXPIRED, | + | | NFS4ERR_FBIG, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, NFS4ERR_IO, | + | | NFS4ERR_ISDIR, NFS4ERR_MOVED, | + | | NFS4ERR_NAMETOOLONG, NFS4ERR_NOENT, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOSPC, | + | | NFS4ERR_NOTDIR, NFS4ERR_NOTSUP, | + | | NFS4ERR_NO_GRACE, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_PERM, NFS4ERR_RECLAIM_BAD, | + | | NFS4ERR_RECLAIM_CONFLICT, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_SHARE_DENIED, NFS4ERR_STALE, | + | | NFS4ERR_STALE_CLIENTID, NFS4ERR_SYMLINK, | + | | NFS4ERR_WRONGSEC | + | OPENATTR | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_DQUOT, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_IO, NFS4ERR_MOVED, NFS4ERR_NOENT, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOSPC, | + | | NFS4ERR_NOTSUPP, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE | + | OPEN_CONFIRM | NFS4ERR_ADMIN_REVOKED, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BAD_SEQID, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_BADXDR, NFS4ERR_EXPIRED, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_INVAL, | + | | NFS4ERR_ISDIR, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_STALE_STATEID | + | OPEN_DOWNGRADE | NFS4ERR_ADMIN_REVOKED, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_BAD_SEQID, | + | | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, | + | | NFS4ERR_EXPIRED, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_RESOURCE, NFS4ERR_ROFS, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_STALE_STATEID | + | PUTFH | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, | + | | NFS4ERR_DELAY, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_MOVED, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_WRONGSEC | + | PUTPUBFH | NFS4ERR_DELAY, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_WRONGSEC | + | PUTROOTFH | NFS4ERR_DELAY, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_WRONGSEC | + | READ | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, | + | | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, | + | | NFS4ERR_EXPIRED, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, NFS4ERR_IO, | + | | NFS4ERR_ISDIR, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_LOCKED, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_OPENMODE, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_STALE_STATEID, NFS4ERR_SYMLINK | + | READDIR | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_BAD_COOKIE, | + | | NFS4ERR_DELAY, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOTDIR, | + | | NFS4ERR_NOT_SAME, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE, | + | | NFS4ERR_TOOSMALL | + | READLINK | NFS4ERR_ACCESS, NFS4ERR_BADHANDLE, | + | | NFS4ERR_DELAY, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_ISDIR, | + | | NFS4ERR_MOVED, NFS4ERR_NOTSUP, | + | | NFS4ERR_RESOURCE, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | RELEASE_LOCKOWNER | NFS4ERR_ADMIN_REVOKED, NFS4ERR_BADXDR, | + | | NFS4ERR_EXPIRED, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_LOCKS_HELD, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE_CLIENTID | + | REMOVE | NFS4ERR_ACCESS, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_FILE_OPEN, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, NFS4ERR_IO, | + | | NFS4ERR_MOVED, NFS4ERR_NAMETOOLONG, | + | | NFS4ERR_NOENT, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NOTDIR, NFS4ERR_NOTEMPTY, | + | | NFS4ERR_RESOURCE, NFS4ERR_ROFS, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | RENAME | NFS4ERR_ACCESS, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_DQUOT, NFS4ERR_EXIST, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_FILE_OPEN, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, NFS4ERR_IO, | + | | NFS4ERR_MOVED, NFS4ERR_NAMETOOLONG, | + | | NFS4ERR_NOENT, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NOSPC, NFS4ERR_NOTDIR, | + | | NFS4ERR_NOTEMPTY, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_WRONGSEC, | + | | NFS4ERR_XDEV | + | RENEW | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_BADXDR, NFS4ERR_CB_PATH_DOWN, | + | | NFS4ERR_EXPIRED, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE_CLIENTID | + | RESTOREFH | NFS4ERR_BADHANDLE, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_MOVED, NFS4ERR_RESOURCE, | + | | NFS4ERR_RESTOREFH, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_WRONGSEC | + | SAVEFH | NFS4ERR_BADHANDLE, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_MOVED, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE | + | SECINFO | NFS4ERR_ACCESS, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADNAME, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_INVAL, | + | | NFS4ERR_MOVED, NFS4ERR_NAMETOOLONG, | + | | NFS4ERR_NOENT, NFS4ERR_NOFILEHANDLE, | + | | NFS4ERR_NOTDIR, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT, NFS4ERR_STALE | + | SETATTR | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_ATTRNOTSUPP, NFS4ERR_BADCHAR, | + | | NFS4ERR_BADHANDLE, NFS4ERR_BADOWNER, | + | | NFS4ERR_BADXDR, NFS4ERR_BAD_STATEID, | + | | NFS4ERR_DELAY, NFS4ERR_DQUOT, | + | | NFS4ERR_EXPIRED, NFS4ERR_FBIG, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_ISDIR, | + | | NFS4ERR_LOCKED, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOSPC, | + | | NFS4ERR_OLD_STATEID, NFS4ERR_OPENMODE, | + | | NFS4ERR_PERM, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_STALE_STATEID | + | SETCLIENTID | NFS4ERR_BADXDR, NFS4ERR_CLID_INUSE, | + | | NFS4ERR_INVAL, NFS4ERR_RESOURCE, | + | | NFS4ERR_SERVERFAULT | + | SETCLIENTID_CONFIRM | NFS4ERR_BADXDR, NFS4ERR_CLID_INUSE, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE_CLIENTID | + | VERIFY | NFS4ERR_ACCESS, NFS4ERR_ATTRNOTSUPP, | + | | NFS4ERR_BADCHAR, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_FHEXPIRED, NFS4ERR_GRACE, | + | | NFS4ERR_INVAL, NFS4ERR_IO, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOT_SAME, | + | | NFS4ERR_RESOURCE, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE | + | WRITE | NFS4ERR_ACCESS, NFS4ERR_ADMIN_REVOKED, | + | | NFS4ERR_BADXDR, NFS4ERR_BADHANDLE, | + | | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, | + | | NFS4ERR_DQUOT, NFS4ERR_EXPIRED, | + | | NFS4ERR_FBIG, NFS4ERR_FHEXPIRED, | + | | NFS4ERR_GRACE, NFS4ERR_INVAL, NFS4ERR_IO, | + | | NFS4ERR_ISDIR, NFS4ERR_LEASE_MOVED, | + | | NFS4ERR_LOCKED, NFS4ERR_MOVED, | + | | NFS4ERR_NOFILEHANDLE, NFS4ERR_NOSPC, | + | | NFS4ERR_NXIO, NFS4ERR_OLD_STATEID, | + | | NFS4ERR_OPENMODE, NFS4ERR_RESOURCE, | + | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | + | | NFS4ERR_STALE, NFS4ERR_STALE_STATEID, | + | | NFS4ERR_SYMLINK | + +---------------------+---------------------------------------------+ + + Table 9 + +13.3. Callback operations and their valid errors + + This section contains a table which gives the valid error returns for + each callback operation. The error code NFS4_OK (indicating no + error) is not listed but should be understood to be returnable by all + callback operations with the exception of CB_ILLEGAL. + + Valid error returns for each protocol callback operation + + +-------------+-----------------------------------------------------+ + | Callback | Errors | + | Operation | | + +-------------+-----------------------------------------------------+ + | CB_GETATTR | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, NFS4ERR_DELAY, | + | | NFS4ERR_INVAL, NFS4ERR_SERVERFAULT | + | CB_ILLEGAL | NFS4ERR_BADXDR, NFS4ERR_OP_ILLEGAL | + | CB_RECALL | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, | + | | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, | + | | NFS4ERR_SERVERFAULT | + +-------------+-----------------------------------------------------+ + + Table 10 + +13.4. Errors and the operations that use them + +--------------------------+----------------------------------------+ + | Error | Operations | + +--------------------------+----------------------------------------+ + | NFS4ERR_ACCESS | ACCESS, COMMIT, CREATE, GETATTR, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, READ, | + | | READDIR, READLINK, REMOVE, RENAME, | + | | RENEW, SECINFO, SETATTR, VERIFY, WRITE | + | NFS4ERR_ADMIN_REVOKED | CLOSE, DELEGRETURN, LOCK, LOCKU, OPEN, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, READ, | + | | RELEASE_LOCKOWNER, RENEW, SETATTR, | + | | WRITE | + | NFS4ERR_ATTRNOTSUPP | CREATE, NVERIFY, OPEN, SETATTR, VERIFY | + | NFS4ERR_BADCHAR | CREATE, LINK, LOOKUP, NVERIFY, OPEN, | + | | REMOVE, RENAME, SECINFO, SETATTR, | + | | VERIFY | + | NFS4ERR_BADHANDLE | ACCESS, CB_GETATTR, CB_RECALL, CLOSE, | + | | COMMIT, CREATE, GETATTR, GETFH, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, PUTFH, READ, READDIR, | + | | READLINK, REMOVE, RENAME, RESTOREFH, | + | | SAVEFH, SECINFO, SETATTR, VERIFY, | + | | WRITE | + | NFS4ERR_BADNAME | CREATE, LINK, LOOKUP, OPEN, REMOVE, | + | | RENAME, SECINFO | + | NFS4ERR_BADOWNER | CREATE, OPEN, SETATTR | + | NFS4ERR_BADTYPE | CREATE | + | NFS4ERR_BADXDR | ACCESS, CB_GETATTR, CB_ILLEGAL, | + | | CB_RECALL, CLOSE, COMMIT, CREATE, | + | | DELEGPURGE, DELEGRETURN, GETATTR, | + | | ILLEGAL, LINK, LOCK, LOCKT, LOCKU, | + | | LOOKUP, NVERIFY, OPEN, OPENATTR, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, PUTFH, | + | | READ, READDIR, RELEASE_LOCKOWNER, | + | | REMOVE, RENAME, RENEW, SECINFO, | + | | SETATTR, SETCLIENTID, | + | | SETCLIENTID_CONFIRM, VERIFY, WRITE | + | NFS4ERR_BAD_COOKIE | READDIR | + | NFS4ERR_BAD_RANGE | LOCK, LOCKT, LOCKU | + | NFS4ERR_BAD_SEQID | CLOSE, LOCK, LOCKU, OPEN, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE | + | NFS4ERR_BAD_STATEID | CB_RECALL, CLOSE, DELEGRETURN, LOCK, | + | | LOCKU, OPEN, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, READ, SETATTR, WRITE | + | NFS4ERR_CB_PATH_DOWN | RENEW | + | NFS4ERR_CLID_INUSE | SETCLIENTID, SETCLIENTID_CONFIRM | + | NFS4ERR_DEADLOCK | LOCK | + | NFS4ERR_DELAY | ACCESS, CB_GETATTR, CB_RECALL, CLOSE, | + | | CREATE, GETATTR, LINK, LOCK, LOCKT, | + | | LOOKUPP, NVERIFY, OPEN, OPENATTR, | + | | OPEN_DOWNGRADE, PUTFH, PUTPUBFH, | + | | PUTROOTFH, READ, READDIR, READLINK, | + | | REMOVE, RENAME, SECINFO, SETATTR, | + | | VERIFY, WRITE | + | NFS4ERR_DENIED | LOCK, LOCKT | + | NFS4ERR_DQUOT | CREATE, LINK, OPEN, OPENATTR, RENAME, | + | | SETATTR, WRITE | + | NFS4ERR_EXIST | CREATE, LINK, OPEN, RENAME | + | NFS4ERR_EXPIRED | CLOSE, DELEGRETURN, LOCK, LOCKU, OPEN, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, READ, | + | | RELEASE_LOCKOWNER, RENEW, SETATTR, | + | | WRITE | + | NFS4ERR_FBIG | OPEN, SETATTR, WRITE | + | NFS4ERR_FHEXPIRED | ACCESS, CLOSE, COMMIT, CREATE, | + | | GETATTR, GETFH, LINK, LOCK, LOCKT, | + | | LOCKU, LOOKUP, LOOKUPP, NVERIFY, OPEN, | + | | OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, PUTFH, READ, READDIR, | + | | READLINK, REMOVE, RENAME, RESTOREFH, | + | | SAVEFH, SECINFO, SETATTR, VERIFY, | + | | WRITE | + | NFS4ERR_FILE_OPEN | LINK, REMOVE, RENAME | + | NFS4ERR_GRACE | GETATTR, LOCK, LOCKT, LOCKU, NVERIFY, | + | | OPEN, READ, REMOVE, RENAME, SETATTR, | + | | VERIFY, WRITE | + | NFS4ERR_INVAL | ACCESS, CB_GETATTR, CLOSE, COMMIT, | + | | CREATE, DELEGRETURN, GETATTR, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, NVERIFY, | + | | OPEN, OPEN_CONFIRM, OPEN_DOWNGRADE, | + | | READ, READDIR, READLINK, REMOVE, | + | | RENAME, SECINFO, SETATTR, SETCLIENTID, | + | | VERIFY, WRITE | + | NFS4ERR_IO | ACCESS, COMMIT, CREATE, GETATTR, LINK, | + | | LOOKUP, LOOKUPP, NVERIFY, OPEN, | + | | OPENATTR, READ, READDIR, READLINK, | + | | REMOVE, RENAME, SETATTR, VERIFY, WRITE | + | NFS4ERR_ISDIR | CLOSE, COMMIT, LINK, LOCK, LOCKT, | + | | LOCKU, OPEN, OPEN_CONFIRM, READ, | + | | READLINK, SETATTR, WRITE | + | NFS4ERR_LEASE_MOVED | CLOSE, DELEGPURGE, DELEGRETURN, LOCK, | + | | LOCKT, LOCKU, READ, RELEASE_LOCKOWNER, | + | | RENEW, WRITE | + | NFS4ERR_LOCKED | READ, SETATTR, WRITE | + | NFS4ERR_LOCKS_HELD | CLOSE, RELEASE_LOCKOWNER | + | NFS4ERR_LOCK_NOTSUPP | LOCK | + | NFS4ERR_LOCK_RANGE | LOCK, LOCKT, LOCKU | + | NFS4ERR_MLINK | LINK | + | NFS4ERR_MOVED | ACCESS, CLOSE, COMMIT, CREATE, | + | | DELEGRETURN, GETATTR, GETFH, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, PUTFH, READ, READDIR, | + | | READLINK, REMOVE, RENAME, RESTOREFH, | + | | SAVEFH, SECINFO, SETATTR, VERIFY, | + | | WRITE | + | NFS4ERR_NAMETOOLONG | CREATE, LINK, LOOKUP, OPEN, REMOVE, | + | | RENAME, SECINFO | + | NFS4ERR_NOENT | LINK, LOOKUP, LOOKUPP, OPEN, OPENATTR, | + | | REMOVE, RENAME, SECINFO | + | NFS4ERR_NOFILEHANDLE | ACCESS, CLOSE, COMMIT, CREATE, | + | | DELEGRETURN, GETATTR, GETFH, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, READ, READDIR, | + | | READLINK, REMOVE, RENAME, SAVEFH, | + | | SECINFO, SETATTR, VERIFY, WRITE | + | NFS4ERR_NOSPC | CREATE, LINK, OPEN, OPENATTR, RENAME, | + | | SETATTR, WRITE | + | NFS4ERR_NOTDIR | CREATE, LINK, LOOKUP, LOOKUPP, OPEN, | + | | READDIR, REMOVE, RENAME, SECINFO | + | NFS4ERR_NOTEMPTY | REMOVE, RENAME | + | NFS4ERR_NOTSUP | OPEN, READLINK | + | NFS4ERR_NOTSUPP | DELEGPURGE, DELEGRETURN, LINK, | + | | OPENATTR | + | NFS4ERR_NOT_SAME | READDIR, VERIFY | + | NFS4ERR_NO_GRACE | LOCK, OPEN | + | NFS4ERR_NXIO | WRITE | + | NFS4ERR_OLD_STATEID | CLOSE, DELEGRETURN, LOCK, LOCKU, OPEN, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, READ, | + | | SETATTR, WRITE | + | NFS4ERR_OPENMODE | LOCK, READ, SETATTR, WRITE | + | NFS4ERR_OP_ILLEGAL | CB_ILLEGAL, ILLEGAL | + | NFS4ERR_PERM | CREATE, OPEN, SETATTR | + | NFS4ERR_RECLAIM_BAD | LOCK, OPEN | + | NFS4ERR_RECLAIM_CONFLICT | LOCK, OPEN | + | NFS4ERR_RESOURCE | ACCESS, CLOSE, COMMIT, CREATE, | + | | DELEGPURGE, DELEGRETURN, GETATTR, | + | | GETFH, LINK, LOCK, LOCKT, LOCKU, | + | | LOOKUP, LOOKUPP, OPEN, OPENATTR, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, READ, | + | | READDIR, READLINK, RELEASE_LOCKOWNER, | + | | REMOVE, RENAME, RENEW, RESTOREFH, | + | | SAVEFH, SECINFO, SETATTR, SETCLIENTID, | + | | SETCLIENTID_CONFIRM, VERIFY, WRITE | + | NFS4ERR_RESTOREFH | RESTOREFH | + | NFS4ERR_ROFS | COMMIT, CREATE, LINK, OPEN, OPENATTR, | + | | OPEN_DOWNGRADE, REMOVE, RENAME, | + | | SETATTR, WRITE | + | NFS4ERR_SAME | NVERIFY | + | NFS4ERR_SERVERFAULT | ACCESS, CB_GETATTR, CB_RECALL, CLOSE, | + | | COMMIT, CREATE, DELEGPURGE, | + | | DELEGRETURN, GETATTR, GETFH, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, PUTFH, PUTPUBFH, | + | | PUTROOTFH, READ, READDIR, READLINK, | + | | RELEASE_LOCKOWNER, REMOVE, RENAME, | + | | RENEW, RESTOREFH, SAVEFH, SECINFO, | + | | SETATTR, SETCLIENTID, | + | | SETCLIENTID_CONFIRM, VERIFY, WRITE | + | NFS4ERR_SHARE_DENIED | OPEN | + | NFS4ERR_STALE | ACCESS, CLOSE, COMMIT, CREATE, | + | | DELEGRETURN, GETATTR, GETFH, LINK, | + | | LOCK, LOCKT, LOCKU, LOOKUP, LOOKUPP, | + | | NVERIFY, OPEN, OPENATTR, OPEN_CONFIRM, | + | | OPEN_DOWNGRADE, PUTFH, READ, READDIR, | + | | READLINK, REMOVE, RENAME, RESTOREFH, | + | | SAVEFH, SECINFO, SETATTR, VERIFY, | + | | WRITE | + | NFS4ERR_STALE_CLIENTID | DELEGPURGE, LOCK, LOCKT, OPEN, | + | | RELEASE_LOCKOWNER, RENEW, | + | | SETCLIENTID_CONFIRM | + | NFS4ERR_STALE_STATEID | CLOSE, DELEGRETURN, LOCK, LOCKU, | + | | OPEN_CONFIRM, OPEN_DOWNGRADE, READ, | + | | SETATTR, WRITE | + | NFS4ERR_SYMLINK | COMMIT, LOOKUP, LOOKUPP, OPEN, READ, | + | | WRITE | + | NFS4ERR_TOOSMALL | READDIR | + | NFS4ERR_WRONGSEC | LINK, LOOKUP, LOOKUPP, OPEN, PUTFH, | + | | PUTPUBFH, PUTROOTFH, RENAME, RESTOREFH | + | NFS4ERR_XDEV | LINK, RENAME | + +--------------------------+----------------------------------------+ + Table 11 + +14. NFS version 4 Requests For the NFS version 4 RPC program, there are two traditional RPC procedures: NULL and COMPOUND. All other functionality is defined as a set of operations and these operations are defined in normal XDR/ RPC syntax and semantics. However, these operations are encapsulated within the COMPOUND procedure. This requires that the client combine one or more of the NFS version 4 operations into a single request. The NFS4_CALLBACK program is used to provide server to client signaling and is constructed in a similar fashion as the NFS version @@ -6256,21 +9615,21 @@ NFS4_CALLBACK program. There is no predefined RPC program number for the NFS4_CALLBACK program. It is up to the client to specify a program number in the "transient" program range. The program and port number of the NFS4_CALLBACK program are provided by the client as part of the SETCLIENTID/SETCLIENTID_CONFIRM sequence. The program and port can be changed by another SETCLIENTID/SETCLIENTID_CONFIRM sequence, and it is possible to use the sequence to change them within a client incarnation without removing relevant leased client state. -13.1. Compound Procedure +14.1. Compound Procedure The COMPOUND procedure provides the opportunity for better performance within high latency networks. The client can avoid cumulative latency of multiple RPCs by combining multiple dependent operations into a single COMPOUND procedure. A compound operation may provide for protocol simplification by allowing the client to combine basic procedures into a single request that is customized for the client's environment. The CB_COMPOUND procedure precisely parallels the features of @@ -6287,21 +9646,21 @@ +------------+-----+--------+-----------------------+-- |last status | tag | numres | status + op + results | +------------+-----+--------+-----------------------+-- The numops and numres fields, used in the depiction above, represent the count for the counted array encoding use to signify the number of arguments or results encoded in the request and response. As per the XDR encoding, these counts must match exactly the number of operation arguments or results encoded. -13.2. Evaluation of a Compound Request +14.2. Evaluation of a Compound Request The server will process the COMPOUND procedure by evaluating each of the operations within the COMPOUND procedure in order. Each component operation consists of a 32 bit operation code, followed by the argument of length determined by the type of operation. The results of each operation are encoded in sequence into a reply buffer. The results of each operation are preceded by the opcode and a status code (normally zero). If an operation results in a non-zero status code, the status will be encoded and evaluation of the compound sequence will halt and the reply will be returned. Note @@ -6323,108 +9682,103 @@ processing has proceeded. Therefore, the client should avoid overly complex COMPOUND procedures in the event of the failure of an operation within the procedure. Each operation assumes a "current" and "saved" filehandle that is available as part of the execution context of the compound request. Operations may set, change, or return the current filehandle. The "saved" filehandle is used for temporary storage of a filehandle value and as operands for the RENAME and LINK operations. -13.3. Synchronous Modifying Operations +14.3. Synchronous Modifying Operations NFS version 4 operations that modify the filesystem are synchronous. When an operation is successfully completed at the server, the client can depend that any data associated with the request is now on stable storage (the one exception is in the case of the file data in a WRITE operation with the UNSTABLE option specified). This implies that any previous operations within the same compound request are also reflected in stable storage. This behavior enables the client's ability to recover from a partially executed compound request which may resulted from the failure of the server. For example, if a compound request contains operations A and B and the server is unable to send a response to the client, depending on the progress the server made in servicing the request the result of both operations may be reflected in stable storage or just operation A may be reflected. The server must not have just the results of operation B in stable storage. -13.4. Operation Values +14.4. Operation Values The operations encoded in the COMPOUND procedure are identified by operation values. To avoid overlap with the RPC procedure numbers, operations 0 (zero) and 1 are not defined. Operation 2 is not defined but reserved for future use with minor versioning. -14. NFS version 4 Procedures +15. NFS version 4 Procedures -14.1. Procedure 0: NULL - No Operation +15.1. Procedure 0: NULL - No Operation -14.1.1. SYNOPSIS +15.1.1. SYNOPSIS -14.1.2. ARGUMENT +15.1.2. ARGUMENT void; -14.1.3. RESULT +15.1.3. RESULT void; -14.1.4. DESCRIPTION +15.1.4. DESCRIPTION Standard NULL procedure. Void argument, void response. This procedure has no functionality associated with it. Because of this it is sometimes used to measure the overhead of processing a service request. Therefore, the server should ensure that no unnecessary work is done in servicing this procedure. -14.1.5. ERRORS - - None. - -14.2. Procedure 1: COMPOUND - Compound Operations +15.2. Procedure 1: COMPOUND - Compound Operations -14.2.1. SYNOPSIS +15.2.1. SYNOPSIS compoundargs -> compoundres -14.2.2. ARGUMENT +15.2.2. ARGUMENT union nfs_argop4 switch (nfs_opnum4 argop) { case : ; ... }; struct COMPOUND4args { - utf8str_cs tag; + comptag4 tag; uint32_t minorversion; nfs_argop4 argarray<>; }; -14.2.3. RESULT +15.2.3. RESULT union nfs_resop4 switch (nfs_opnum4 resop) { case : ; ... }; struct COMPOUND4res { nfsstat4 status; - utf8str_cs tag; + comptag4 tag; nfs_resop4 resarray<>; - }; -14.2.4. DESCRIPTION +15.2.4. DESCRIPTION The COMPOUND procedure is used to combine one or more of the NFS operations into a single RPC request. The main NFS RPC program has two main procedures: NULL and COMPOUND. All other operations use the COMPOUND procedure as a wrapper. The COMPOUND procedure is used to combine individual operations into a single RPC request. The server interprets each of the operations in turn. If an operation is executed by the server and the status of that operation is NFS4_OK, then the next operation in the COMPOUND @@ -6491,69 +9845,65 @@ the ILLEGAL return results will set to NFS4ERR_OP_ILLEGAL. The COMPOUND procedure's return results will also be NFS4ERR_OP_ILLEGAL. The definition of the "tag" in the request is left to the implementor. It may be used to summarize the content of the compound request for the benefit of packet sniffers and engineers debugging implementations. However, the value of "tag" in the response SHOULD be the same value as provided in the request. This applies to the tag field of the CB_COMPOUND procedure as well. -14.2.5. IMPLEMENTATION +15.2.5. IMPLEMENTATION Since an error of any type may occur after only a portion of the operations have been evaluated, the client must be prepared to recover from any failure. If the source of an NFS4ERR_RESOURCE error was a complex or lengthy set of operations, it is likely that if the number of operations were reduced the server would be able to evaluate them successfully. Therefore, the client is responsible for dealing with this type of complexity in recovery. -14.2.6. ERRORS - - All errors defined in the protocol - -14.3. Operation 3: ACCESS - Check Access Rights +15.3. Operation 3: ACCESS - Check Access Rights -14.3.1. SYNOPSIS +15.3.1. SYNOPSIS (cfh), accessreq -> supported, accessrights -14.3.2. ARGUMENT +15.3.2. ARGUMENT const ACCESS4_READ = 0x00000001; const ACCESS4_LOOKUP = 0x00000002; const ACCESS4_MODIFY = 0x00000004; const ACCESS4_EXTEND = 0x00000008; const ACCESS4_DELETE = 0x00000010; const ACCESS4_EXECUTE = 0x00000020; struct ACCESS4args { /* CURRENT_FH: object */ uint32_t access; }; -14.3.3. RESULT +15.3.3. RESULT struct ACCESS4resok { uint32_t supported; uint32_t access; }; union ACCESS4res switch (nfsstat4 status) { case NFS4_OK: ACCESS4resok resok4; default: void; }; -14.3.4. DESCRIPTION +15.3.4. DESCRIPTION ACCESS determines the access rights that a user, as identified by the credentials in the RPC request, has with respect to the file system object specified by the current filehandle. The client encodes the set of access rights that are to be checked in the bit mask "access". The server checks the permissions encoded in the bit mask. If a status of NFS4_OK is returned, two bit masks are included in the response. The first, "supported", represents the access rights for which the server can verify reliably. The second, "access", represents the access rights available to the user for the filehandle @@ -6582,21 +9932,21 @@ directory entries. ACCESS4_EXTEND Write new data or add directory entries. ACCESS4_DELETE Delete an existing directory entry. ACCESS4_EXECUTE Execute file (no meaning for a directory). On success, the current filehandle retains its value. -14.3.5. IMPLEMENTATION +15.3.5. IMPLEMENTATION In general, it is not sufficient for the client to attempt to deduce access permissions by inspecting the uid, gid, and mode fields in the file attributes or by attempting to interpret the contents of the ACL attribute. This is because the server may perform uid or gid mapping or enforce additional access control restrictions. It is also possible that the server may not be in the same ID space as the client. In these cases (and perhaps others), the client can not reliably perform an access check with only current file attributes. @@ -6627,134 +9977,97 @@ ACCESS4_DELETE bit if set on an access request on a non-directory object. In these systems, delete permission on a file is determined by the access permissions on the directory in which the file resides, instead of being determined by the permissions of the file itself. Therefore, the mask returned enumerating which access rights can be determined will have the ACCESS4_DELETE value set to 0. This indicates to the client that the server was unable to check that particular access right. The ACCESS4_DELETE bit in the access mask returned will then be ignored by the client. -14.3.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.4. Operation 4: CLOSE - Close File +15.4. Operation 4: CLOSE - Close File -14.4.1. SYNOPSIS +15.4.1. SYNOPSIS (cfh), seqid, open_stateid -> open_stateid -14.4.2. ARGUMENT +15.4.2. ARGUMENT struct CLOSE4args { /* CURRENT_FH: object */ seqid4 seqid; stateid4 open_stateid; }; -14.4.3. RESULT +15.4.3. RESULT union CLOSE4res switch (nfsstat4 status) { case NFS4_OK: stateid4 open_stateid; default: void; }; -14.4.4. DESCRIPTION +15.4.4. DESCRIPTION The CLOSE operation releases share reservations for the regular or named attribute file as specified by the current filehandle. The share reservations and other state information released at the server as a result of this CLOSE is only associated with the supplied stateid. The sequence id provides for the correct ordering. State associated with other OPENs is not affected. If record locks are held, the client SHOULD release all locks before issuing a CLOSE. The server MAY free all outstanding locks on CLOSE but some servers may not support the CLOSE of a file that still has record locks held. The server MUST return failure if any locks would exist after the CLOSE. On success, the current filehandle retains its value. -14.4.5. IMPLEMENTATION +15.4.5. IMPLEMENTATION Even though CLOSE returns a stateid, this stateid is not useful to the client and should be treated as deprecated. CLOSE "shuts down" the state associated with all OPENs for the file by a single open_owner. As noted above, CLOSE will either release all file locking state or return an error. Therefore, the stateid returned by CLOSE is not useful for operations that follow. -14.4.6. ERRORS - - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_SEQID - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCKS_HELD - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_OLD_STATEID - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.5. Operation 5: COMMIT - Commit Cached Data +15.5. Operation 5: COMMIT - Commit Cached Data -14.5.1. SYNOPSIS +15.5.1. SYNOPSIS (cfh), offset, count -> verifier -14.5.2. ARGUMENT +15.5.2. ARGUMENT struct COMMIT4args { /* CURRENT_FH: file */ offset4 offset; count4 count; }; -14.5.3. RESULT +15.5.3. RESULT struct COMMIT4resok { verifier4 writeverf; }; union COMMIT4res switch (nfsstat4 status) { case NFS4_OK: COMMIT4resok resok4; default: void; }; -14.5.4. DESCRIPTION +15.5.4. DESCRIPTION The COMMIT operation forces or flushes data to stable storage for the file specified by the current filehandle. The flushed data is that which was previously written with a WRITE operation which had the stable field set to UNSTABLE4. The offset specifies the position within the file where the flush is to begin. An offset value of 0 (zero) means to flush data starting at the beginning of the file. The count specifies the number of bytes of data to flush. If count is 0 (zero), a flush from offset to @@ -6766,21 +10079,21 @@ COMMIT. The client does this by comparing the write verifier returned from the initial writes and the verifier returned by the COMMIT operation. The server must vary the value of the write verifier at each server event or instantiation that may lead to a loss of uncommitted data. Most commonly this occurs when the server is rebooted; however, other events at the server may result in uncommitted data loss as well. On success, the current filehandle retains its value. -14.5.5. IMPLEMENTATION +15.5.5. IMPLEMENTATION The COMMIT operation is similar in operation and semantics to the POSIX fsync(2) system call that synchronizes a file's state with the disk (file data and metadata is flushed to disk or stable storage). COMMIT performs the same operation for a client, flushing any unsynchronized data and metadata on the server to the server's disk or stable storage for the specified file. Like fsync(2), it may be that there is some modified data or no modified data to synchronize. The data may have been synchronized by the server's normal periodic buffer synchronization activity. COMMIT should return NFS4_OK, @@ -6834,43 +10147,27 @@ one buffer, it might be worthwhile retransmitting all of the buffers in WRITE requests with the stable parameter set to UNSTABLE4 and then retransmitting the COMMIT operation to flush all of the data on the server to stable storage. The timing of these retransmissions is left to the implementor. The above description applies to page-cache-based systems as well as buffer-cache-based systems. In those systems, the virtual memory system will need to be modified instead of the buffer cache. -14.5.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_ISDIR - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.6. Operation 6: CREATE - Create a Non-Regular File Object +15.6. Operation 6: CREATE - Create a Non-Regular File Object -14.6.1. SYNOPSIS +15.6.1. SYNOPSIS (cfh), name, type, attrs -> (cfh), change_info, attrs_set -14.6.2. ARGUMENT +15.6.2. ARGUMENT union createtype4 switch (nfs_ftype4 type) { case NF4LNK: linktext4 linkdata; case NF4BLK: case NF4CHR: specdata4 devdata; case NF4SOCK: case NF4FIFO: case NF4DIR: @@ -6879,52 +10176,56 @@ void; /* server should return NFS4ERR_BADTYPE */ }; struct CREATE4args { /* CURRENT_FH: directory for creation */ createtype4 objtype; component4 objname; fattr4 createattrs; }; -14.6.3. RESULT +15.6.3. RESULT struct CREATE4resok { change_info4 cinfo; bitmap4 attrset; /* attributes set */ }; union CREATE4res switch (nfsstat4 status) { case NFS4_OK: CREATE4resok resok4; default: void; }; -14.6.4. DESCRIPTION +15.6.4. DESCRIPTION The CREATE operation creates a non-regular file object in a directory with a given name. The OPEN operation MUST be used to create a regular file. The objname specifies the name for the new object. The objtype determines the type of object to be created: directory, symlink, etc. If an object of the same name already exists in the directory, the server will return the error NFS4ERR_EXIST. For the directory where the new file object was created, the server returns change_info4 information in cinfo. With the atomic field of the change_info4 struct, the server will indicate if the before and after change attributes were obtained atomically with respect to the file object creation. + If the objname is of zero length, NFS4ERR_INVAL will be returned. + The objname is also subject to the normal UTF-8, character support, + and name checks. See Section 12.3 for further discussion. + If the objname has a length of 0 (zero), or if objname does not obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned. The current filehandle is replaced by that of the new object. The createattrs specifies the initial set of attributes for the object. The set of attributes may include any writable attribute valid for the object type. When the operation is successful, the server will return to the client an attribute mask signifying which attributes were successfully set for the object. @@ -6948,72 +10249,45 @@ object is created in, or whatever else the server's operating environment or filesystem semantics dictate. This applies to the OPEN operation too. Conversely, it is possible the client will specify in createattrs an owner attribute or group attribute or ACL that the principal indicated the RPC call's credentials does not have permissions to create files for. The error to be returned in this instance is NFS4ERR_PERM. This applies to the OPEN operation too. -14.6.5. IMPLEMENTATION +15.6.5. IMPLEMENTATION If the client desires to set attribute values after the create, a SETATTR operation can be added to the COMPOUND request so that the appropriate attributes will be set. -14.6.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ATTRNOTSUPP - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADOWNER - NFS4ERR_BADTYPE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXIST - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NOTDIR - NFS4ERR_PERM - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.7. Operation 7: DELEGPURGE - Purge Delegations Awaiting Recovery +15.7. Operation 7: DELEGPURGE - Purge Delegations Awaiting Recovery -14.7.1. SYNOPSIS +15.7.1. SYNOPSIS clientid -> -14.7.2. ARGUMENT +15.7.2. ARGUMENT struct DELEGPURGE4args { clientid4 clientid; }; -14.7.3. RESULT +15.7.3. RESULT struct DELEGPURGE4res { nfsstat4 status; }; -14.7.4. DESCRIPTION +15.7.4. DESCRIPTION Purges all of the delegations awaiting recovery for a given client. This is useful for clients which do not commit delegation information to stable storage to indicate that conflicting requests need not be delayed by the server awaiting recovery of delegation information. This operation should be used by clients that record delegation information on stable storage on the client. In this case, DELEGPURGE should be issued immediately after doing delegation recovery on all delegations known to the client. Doing so will @@ -7022,103 +10296,76 @@ clients who make requests that conflict with the unrecovered delegations. The set of delegations known to the server and the client may be different. The reason for this is that a client may fail after making a request which resulted in delegation but before it received the results and committed them to the client's stable storage. The server MAY support DELEGPURGE, but if it does not, it MUST NOT support CLAIM_DELEGATE_PREV. -14.7.5. ERRORS - - NFS4ERR_BADXDR - NFS4ERR_NOTSUPP - NFS4ERR_LEASE_MOVED - NFS4ERR_MOVED - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE_CLIENTID - -14.8. Operation 8: DELEGRETURN - Return Delegation +15.8. Operation 8: DELEGRETURN - Return Delegation -14.8.1. SYNOPSIS +15.8.1. SYNOPSIS (cfh), stateid -> -14.8.2. ARGUMENT +15.8.2. ARGUMENT struct DELEGRETURN4args { /* CURRENT_FH: delegated file */ stateid4 deleg_stateid; }; -14.8.3. RESULT +15.8.3. RESULT struct DELEGRETURN4res { nfsstat4 status; }; -14.8.4. DESCRIPTION +15.8.4. DESCRIPTION Returns the delegation represented by the current filehandle and stateid. Delegations may be returned when recalled or voluntarily (i.e., before the server has recalled them). In either case the client must properly propagate state changed under the context of the delegation to the server before returning the delegation. -14.8.5. ERRORS - - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_EXPIRED - NFS4ERR_INVAL - NFS4ERR_LEASE_MOVED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTSUPP - NFS4ERR_OLD_STATEID - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.9. Operation 9: GETATTR - Get Attributes +15.9. Operation 9: GETATTR - Get Attributes -14.9.1. SYNOPSIS +15.9.1. SYNOPSIS (cfh), attrbits -> attrbits, attrvals -14.9.2. ARGUMENT +15.9.2. ARGUMENT struct GETATTR4args { /* CURRENT_FH: directory or file */ bitmap4 attr_request; }; -14.9.3. RESULT +15.9.3. RESULT struct GETATTR4resok { fattr4 obj_attributes; }; union GETATTR4res switch (nfsstat4 status) { case NFS4_OK: GETATTR4resok resok4; default: void; }; -14.9.4. DESCRIPTION +15.9.4. DESCRIPTION The GETATTR operation will obtain attributes for the filesystem object specified by the current filehandle. The client sets a bit in the bitmap argument for each attribute value that it would like the server to return. The server returns an attribute bitmap that indicates the attribute values for which it was able to return, followed by the attribute values ordered lowest attribute number first. The server must return a value for each attribute that the client @@ -7127,187 +10374,133 @@ then it must not return the attribute value and must not set the attribute bit in the result bitmap. The server must return an error if it supports an attribute but cannot obtain its value. In that case no attribute values will be returned. All servers must support the mandatory attributes as specified in the section "File Attributes". On success, the current filehandle retains its value. -14.9.5. IMPLEMENTATION -14.9.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE +15.9.5. IMPLEMENTATION -14.10. Operation 10: GETFH - Get Current Filehandle +15.10. Operation 10: GETFH - Get Current Filehandle -14.10.1. SYNOPSIS +15.10.1. SYNOPSIS (cfh) -> filehandle -14.10.2. ARGUMENT +15.10.2. ARGUMENT /* CURRENT_FH: */ void; -14.10.3. RESULT +15.10.3. RESULT struct GETFH4resok { nfs_fh4 object; }; union GETFH4res switch (nfsstat4 status) { case NFS4_OK: GETFH4resok resok4; default: void; }; -14.10.4. DESCRIPTION +15.10.4. DESCRIPTION This operation returns the current filehandle value. On success, the current filehandle retains its value. -14.10.5. IMPLEMENTATION +15.10.5. IMPLEMENTATION Operations that change the current filehandle like LOOKUP or CREATE do not automatically return the new filehandle as a result. For instance, if a client needs to lookup a directory entry and obtain its filehandle then the following request is needed. PUTFH (directory filehandle) LOOKUP (entry name) GETFH -14.10.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_FHEXPIRED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.11. Operation 11: LINK - Create Link to a File +15.11. Operation 11: LINK - Create Link to a File -14.11.1. SYNOPSIS +15.11.1. SYNOPSIS (sfh), (cfh), newname -> (cfh), change_info -14.11.2. ARGUMENT +15.11.2. ARGUMENT struct LINK4args { /* SAVED_FH: source object */ /* CURRENT_FH: target directory */ component4 newname; }; -14.11.3. RESULT +15.11.3. RESULT struct LINK4resok { change_info4 cinfo; }; union LINK4res switch (nfsstat4 status) { case NFS4_OK: LINK4resok resok4; default: void; }; -14.11.4. DESCRIPTION +15.11.4. DESCRIPTION The LINK operation creates an additional newname for the file represented by the saved filehandle, as set by the SAVEFH operation, in the directory represented by the current filehandle. The existing file and the target directory must reside within the same filesystem on the server. On success, the current filehandle will continue to be the target directory. If an object exists in the target directory with the same name as newname, the server must return NFS4ERR_EXIST. For the target directory, the server returns change_info4 information in cinfo. With the atomic field of the change_info4 struct, the server will indicate if the before and after change attributes were obtained atomically with respect to the link creation. If the newname has a length of 0 (zero), or if newname does not obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned. -14.11.5. IMPLEMENTATION +15.11.5. IMPLEMENTATION Changes to any property of the "hard" linked files are reflected in all of the linked files. When a link is made to a file, the attributes for the file should have a value for numlinks that is one greater than the value before the LINK operation. The statement "file and the target directory must reside within the same filesystem on the server" means that the fsid fields in the attributes for the objects are the same. If they reside on different filesystems, the error, NFS4ERR_XDEV, is returned. On some servers, the filenames, "." and "..", are illegal as newname. In the case that newname is already linked to the file represented by the saved filehandle, the server will return NFS4ERR_EXIST. Note that symbolic links are created with the CREATE operation. -14.11.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXIST - NFS4ERR_FHEXPIRED - NFS4ERR_FILE_OPEN - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_ISDIR - NFS4ERR_MLINK - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NOTDIR - NFS4ERR_NOTSUPP - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_WRONGSEC - NFS4ERR_XDEV - -14.12. Operation 12: LOCK - Create Lock +15.12. Operation 12: LOCK - Create Lock -14.12.1. SYNOPSIS +15.12.1. SYNOPSIS (cfh) locktype, reclaim, offset, length, locker -> stateid -14.12.2. ARGUMENT +15.12.2. ARGUMENT enum nfs_lock_type4 { READ_LT = 1, WRITE_LT = 2, READW_LT = 3, /* blocking read */ WRITEW_LT = 4 /* blocking write */ }; /* * For LOCK, transition from open_owner to new lock_owner */ @@ -7338,21 +10531,21 @@ */ struct LOCK4args { /* CURRENT_FH: file */ nfs_lock_type4 locktype; bool reclaim; offset4 offset; length4 length; locker4 locker; }; -14.12.3. RESULT +15.12.3. RESULT struct LOCK4denied { offset4 offset; length4 length; nfs_lock_type4 locktype; lock_owner4 owner; }; struct LOCK4resok { stateid4 lock_stateid; @@ -7360,21 +10553,21 @@ union LOCK4res switch (nfsstat4 status) { case NFS4_OK: LOCK4resok resok4; case NFS4ERR_DENIED: LOCK4denied denied; default: void; }; -14.12.4. DESCRIPTION +15.12.4. DESCRIPTION The LOCK operation requests a record lock for the byte range specified by the offset and length parameters. The lock type is also specified to be one of the nfs_lock_type4s. If this is a reclaim request, the reclaim parameter will be TRUE; Bytes in a file may be locked even if those bytes are not currently allocated to the file. To lock the file from a specific offset through the end-of-file (no matter how long the file actually is) use a length field with all bits set to 1 (one). If the length is zero, @@ -7387,27 +10580,27 @@ beyond the last byte offset of the 32-bit range, but does not include the last byte offset of the 32-bit and all of the byte offsets beyond it, up to the end of the valid 64-bit range, such a 32-bit server MUST return the error NFS4ERR_BAD_RANGE. In the case that the lock is denied, the owner, offset, and length of a conflicting lock are returned. On success, the current filehandle retains its value. -14.12.5. IMPLEMENTATION +15.12.5. IMPLEMENTATION If the server is unable to determine the exact offset and length of the conflicting lock, the same offset and length that were provided - in the arguments should be returned in the denied results. The File - Locking section contains a full description of this and the other - file locking operations. + in the arguments should be returned in the denied results. Section 9 + contains a full description of this and the other file locking + operations. LOCK operations are subject to permission checks and to checks against the access type of the associated file. However, the specific right and modes required for various type of locks, reflect the semantics of the server-exported filesystem, and are not specified by the protocol. For example, Windows 2000 allows a write lock of a file open for READ, while a POSIX-compliant system does not. When the client makes a lock request that corresponds to a range that @@ -7433,254 +10626,176 @@ indicates whether the lock_owner is known to the server or if the lock_owner is new to the server. In the case that the lock_owner is known to the server and has an established lock_seqid, the argument is just the lock_owner and lock_seqid. In the case that the lock_owner is not known to the server, the argument contains not only the lock_owner and lock_seqid but also the open_stateid and open_seqid. The new lock_owner case covers the very first lock done by the lock_owner and offers a method to use the established state of the open_stateid to transition to the use of the lock_owner. -14.12.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_RANGE - NFS4ERR_BAD_SEQID - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_DEADLOCK - NFS4ERR_DELAY - NFS4ERR_DENIED - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCK_NOTSUPP - NFS4ERR_LOCK_RANGE - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NO_GRACE - NFS4ERR_OLD_STATEID - NFS4ERR_OPENMODE - NFS4ERR_RECLAIM_BAD - NFS4ERR_RECLAIM_CONFLICT - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_CLIENTID - NFS4ERR_STALE_STATEID - -14.13. Operation 13: LOCKT - Test For Lock +15.13. Operation 13: LOCKT - Test For Lock -14.13.1. SYNOPSIS +15.13.1. SYNOPSIS (cfh) locktype, offset, length owner -> {void, NFS4ERR_DENIED -> owner} -14.13.2. ARGUMENT +15.13.2. ARGUMENT struct LOCKT4args { /* CURRENT_FH: file */ nfs_lock_type4 locktype; offset4 offset; length4 length; lock_owner4 owner; }; -14.13.3. RESULT +15.13.3. RESULT union LOCKT4res switch (nfsstat4 status) { case NFS4ERR_DENIED: LOCK4denied denied; case NFS4_OK: void; default: void; }; -14.13.4. DESCRIPTION +15.13.4. DESCRIPTION The LOCKT operation tests the lock as specified in the arguments. If a conflicting lock exists, the owner, offset, length, and type of the conflicting lock are returned; if no lock is held, nothing other than NFS4_OK is returned. Lock types READ_LT and READW_LT are processed in the same way in that a conflicting lock test is done without regard to blocking or non-blocking. The same is true for WRITE_LT and WRITEW_LT. The ranges are specified as for LOCK. The NFS4ERR_INVAL and NFS4ERR_BAD_RANGE errors are returned under the same circumstances as for LOCK. On success, the current filehandle retains its value. -14.13.5. IMPLEMENTATION +15.13.5. IMPLEMENTATION If the server is unable to determine the exact offset and length of the conflicting lock, the same offset and length that were provided - in the arguments should be returned in the denied results. The File - Locking section contains further discussion of the file locking - mechanisms. + in the arguments should be returned in the denied results. Section 9 + contains further discussion of the file locking mechanisms. LOCKT uses a lock_owner4 rather a stateid4, as is used in LOCK to identify the owner. This is because the client does not have to open the file to test for the existence of a lock, so a stateid may not be available. The test for conflicting locks should exclude locks for the current lockowner. Note that since such locks are not examined the possible existence of overlapping ranges may not affect the results of LOCKT. If the server does examine locks that match the lockowner for the purpose of range checking, NFS4ERR_LOCK_RANGE may be returned.. In the event that it returns NFS4_OK, clients may do a LOCK and receive NFS4ERR_LOCK_RANGE on the LOCK request because of the flexibility provided to the server. -14.13.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BAD_RANGE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DENIED - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCK_RANGE - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_CLIENTID - -14.14. Operation 14: LOCKU - Unlock File +15.14. Operation 14: LOCKU - Unlock File -14.14.1. SYNOPSIS +15.14.1. SYNOPSIS (cfh) type, seqid, stateid, offset, length -> stateid -14.14.2. ARGUMENT +15.14.2. ARGUMENT struct LOCKU4args { /* CURRENT_FH: file */ nfs_lock_type4 locktype; seqid4 seqid; stateid4 lock_stateid; offset4 offset; length4 length; }; -14.14.3. RESULT +15.14.3. RESULT union LOCKU4res switch (nfsstat4 status) { case NFS4_OK: stateid4 lock_stateid; default: void; }; -14.14.4. DESCRIPTION +15.14.4. DESCRIPTION The LOCKU operation unlocks the record lock specified by the parameters. The client may set the locktype field to any value that is legal for the nfs_lock_type4 enumerated type, and the server MUST accept any legal value for locktype. Any legal value for locktype has no effect on the success or failure of the LOCKU operation. The ranges are specified as for LOCK. The NFS4ERR_INVAL and NFS4ERR_BAD_RANGE errors are returned under the same circumstances as for LOCK. On success, the current filehandle retains its value. -14.14.5. IMPLEMENTATION +15.14.5. IMPLEMENTATION If the area to be unlocked does not correspond exactly to a lock actually held by the lockowner the server may return the error NFS4ERR_LOCK_RANGE. This includes the case in which the area is not locked, where the area is a sub-range of the area locked, where it overlaps the area locked without matching exactly or the area specified includes multiple locks held by the lockowner. In all of these cases, allowed by POSIX locking semantics, a client receiving this error, should if it desires support for such operations, simulate the operation using LOCKU on ranges corresponding to locks it actually holds, possibly followed by LOCK requests for the sub- ranges not being unlocked. -14.14.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_RANGE - NFS4ERR_BAD_SEQID - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCK_RANGE - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_OLD_STATEID - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.15. Operation 15: LOOKUP - Lookup Filename +15.15. Operation 15: LOOKUP - Lookup Filename -14.15.1. SYNOPSIS +15.15.1. SYNOPSIS (cfh), component -> (cfh) -14.15.2. ARGUMENT +15.15.2. ARGUMENT struct LOOKUP4args { /* CURRENT_FH: directory */ component4 objname; }; -14.15.3. RESULT +15.15.3. RESULT struct LOOKUP4res { /* CURRENT_FH: object */ nfsstat4 status; }; -14.15.4. DESCRIPTION +15.15.4. DESCRIPTION This operation LOOKUPs or finds a filesystem object using the directory specified by the current filehandle. LOOKUP evaluates the component and if the object exists the current filehandle is replaced with the component's filehandle. If the component cannot be evaluated either because it does not exist or because the client does not have permission to evaluate the component, then an error will be returned and the current filehandle will be unchanged. - If the component is a zero length string or if any component does not - obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned. + If the component is of zero length, NFS4ERR_INVAL will be returned. + The component is also subject to the normal UTF-8, character support, + and name checks. See Section 12.3 for further discussion. -14.15.5. IMPLEMENTATION +15.15.5. IMPLEMENTATION If the client wants to achieve the effect of a multi-component lookup, it may construct a COMPOUND request such as (and obtain each filehandle): PUTFH (directory filehandle) LOOKUP "pub" GETFH LOOKUP "foo" GETFH @@ -7709,118 +10824,83 @@ directory. Note that this operation does not follow symbolic links. The client is responsible for all parsing of filenames including filenames that are modified by symbolic links encountered during the lookup process. If the current filehandle supplied is not a directory but a symbolic link, the error NFS4ERR_SYMLINK is returned as the error. For all other non-directory file types, the error NFS4ERR_NOTDIR is returned. -14.15.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADXDR - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTDIR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_SYMLINK - NFS4ERR_WRONGSEC - -14.16. Operation 16: LOOKUPP - Lookup Parent Directory +15.16. Operation 16: LOOKUPP - Lookup Parent Directory -14.16.1. SYNOPSIS +15.16.1. SYNOPSIS (cfh) -> (cfh) -14.16.2. ARGUMENT +15.16.2. ARGUMENT /* CURRENT_FH: object */ void; -14.16.3. RESULT +15.16.3. RESULT struct LOOKUPP4res { /* CURRENT_FH: directory */ nfsstat4 status; }; -14.16.4. DESCRIPTION +15.16.4. DESCRIPTION The current filehandle is assumed to refer to a regular directory or a named attribute directory. LOOKUPP assigns the filehandle for its parent directory to be the current filehandle. If there is no parent directory an NFS4ERR_NOENT error must be returned. Therefore, NFS4ERR_NOENT will be returned by the server when the current filehandle is at the root or top of the server's file tree. -14.16.5. IMPLEMENTATION +15.16.5. IMPLEMENTATION As for LOOKUP, LOOKUPP will also cross mountpoints. If the current filehandle is not a directory or named attribute directory, the error NFS4ERR_NOTDIR is returned. -14.16.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_FHEXPIRED - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTDIR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.17. Operation 17: NVERIFY - Verify Difference in Attributes +15.17. Operation 17: NVERIFY - Verify Difference in Attributes -14.17.1. SYNOPSIS +15.17.1. SYNOPSIS (cfh), fattr -> - -14.17.2. ARGUMENT +15.17.2. ARGUMENT struct NVERIFY4args { /* CURRENT_FH: object */ fattr4 obj_attributes; }; -14.17.3. RESULT +15.17.3. RESULT struct NVERIFY4res { nfsstat4 status; }; -14.17.4. DESCRIPTION +15.17.4. DESCRIPTION This operation is used to prefix a sequence of operations to be performed if one or more attributes have changed on some filesystem object. If all the attributes match then the error NFS4ERR_SAME must be returned. On success, the current filehandle retains its value. -14.17.5. IMPLEMENTATION +15.17.5. IMPLEMENTATION This operation is useful as a cache validation operator. If the object to which the attributes belong has changed then the following operations may obtain new data associated with that object. For instance, to check if a file has been changed and obtain new data if it has: PUTFH (public) LOOKUP "foobar" NVERIFY attrbits attrs @@ -7828,46 +10908,28 @@ In the case that a recommended attribute is specified in the NVERIFY operation and the server does not support that attribute for the filesystem object, the error NFS4ERR_ATTRNOTSUPP is returned to the client. When the attribute rdattr_error or any write-only attribute (e.g., time_modify_set) is specified, the error NFS4ERR_INVAL is returned to the client. -14.17.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ATTRNOTSUPP - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SAME - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.18. Operation 18: OPEN - Open a Regular File +15.18. Operation 18: OPEN - Open a Regular File -14.18.1. SYNOPSIS +15.18.1. SYNOPSIS (cfh), seqid, share_access, share_deny, owner, openhow, claim -> (cfh), stateid, cinfo, rflags, open_confirm, attrset delegation -14.18.2. ARGUMENT +15.18.2. ARGUMENT /* * Various definitions for OPEN */ enum createmode4 { UNCHECKED4 = 0, GUARDED4 = 1, EXCLUSIVE4 = 2, }; @@ -7971,21 +11033,21 @@ */ struct OPEN4args { seqid4 seqid; uint32_t share_access; uint32_t share_deny; open_owner4 owner; openflag4 openhow; open_claim4 claim; }; -14.18.3. RESULT +15.18.3. RESULT struct open_read_delegation4 { stateid4 stateid; /* Stateid for delegation*/ bool recall; /* Pre-recalled flag for delegations obtained by reclaim (CLAIM_PREVIOUS) */ nfsace4 permissions; /* Defines users who don't need an ACCESS call to open for read */ @@ -8040,37 +11102,37 @@ }; union OPEN4res switch (nfsstat4 status) { case NFS4_OK: /* CURRENT_FH: opened file */ OPEN4resok resok4; default: void; }; -14.18.4. WARNING TO CLIENT IMPLEMENTORS +15.18.4. WARNING TO CLIENT IMPLEMENTORS OPEN resembles LOOKUP in that it generates a filehandle for the client to use. Unlike LOOKUP though, OPEN creates server state on the filehandle. In normal circumstances, the client can only release this state with a CLOSE operation. CLOSE uses the current filehandle to determine which file to close. Therefore the client MUST follow every OPEN operation with a GETFH operation in the same COMPOUND procedure. This will supply the client with the filehandle such that CLOSE can be used appropriately. Simply waiting for the lease on the file to expire is insufficient because the server may maintain the state indefinitely as long as another client does not attempt to make a conflicting access to the same file. -14.18.5. DESCRIPTION +15.18.5. DESCRIPTION The OPEN operation creates and/or opens a regular file in a directory with the provided name. If the file does not exist at the server and creation is desired, specification of the method of creation is provided by the openhow parameter. The client has the choice of three creation methods: UNCHECKED, GUARDED, or EXCLUSIVE. If the current filehandle is a named attribute directory, OPEN will then create or open a named attribute file. Note that exclusive create of a named attribute is not supported. If the createmode is @@ -8118,21 +11180,21 @@ The OPEN operation provides for Windows share reservation capability with the use of the share_access and share_deny fields of the OPEN arguments. The client specifies at OPEN the required share_access and share_deny modes. For clients that do not directly support SHAREs (i.e., UNIX), the expected deny value is DENY_NONE. In the case that there is a existing SHARE reservation that conflicts with the OPEN request, the server returns the error NFS4ERR_SHARE_DENIED. For a complete SHARE request, the client must provide values for the owner and seqid fields for the OPEN argument. For additional - discussion of SHARE semantics see Section 8.9 "Share Reservations". + discussion of SHARE semantics see Section 9.9. In the case that the client is recovering state from a server failure, the claim field of the OPEN argument is used to signify that the request is meant to reclaim state previously held. The "claim" field of the OPEN argument is used to specify the file to be opened and the state information which the client claims to possess. There are four basic claim types which cover the various situations for an OPEN. They are as follows: @@ -8155,43 +11217,41 @@ client's delegation state, and the server MUST support the DELEGPURGE operation. For OPEN requests whose claim type is other than CLAIM_PREVIOUS (i.e., requests other than those devoted to reclaiming opens after a server reboot) that reach the server during its grace or lease expiration period, the server returns an error of NFS4ERR_GRACE. For any OPEN request, the server may return an open delegation, which allows further opens and closes to be handled locally on the client - as described in the section Open Delegation. Note that delegation is - up to the server to decide. The client should never assume that - delegation will or will not be granted in a particular instance. It - should always be prepared for either case. A partial exception is - the reclaim (CLAIM_PREVIOUS) case, in which a delegation type is - claimed. In this case, delegation will always be granted, although - the server may specify an immediate recall in the delegation - structure. + as described in Section 10.4. Note that delegation is up to the + server to decide. The client should never assume that delegation + will or will not be granted in a particular instance. It should + always be prepared for either case. A partial exception is the + reclaim (CLAIM_PREVIOUS) case, in which a delegation type is claimed. + In this case, delegation will always be granted, although the server + may specify an immediate recall in the delegation structure. The rflags returned by a successful OPEN allow the server to return information governing how the open file is to be handled. OPEN4_RESULT_CONFIRM indicates that the client MUST execute an OPEN_CONFIRM operation before using the open file. OPEN4_RESULT_LOCKTYPE_POSIX indicates the server's file locking behavior supports the complete set of Posix locking techniques. From this the client can choose to manage file locking state in a way to handle a mis-match of file locking management. If the component is of zero length, NFS4ERR_INVAL will be returned. The component is also subject to the normal UTF-8, character support, - and name checks. See Section 11.4 "UTF-8 Related Errors" for further - discussion. + and name checks. See Section 12.3 for further discussion. When an OPEN is done and the specified lockowner already has the resulting filehandle open, the result is to "OR" together the new share and deny status together with the existing status. In this case, only a single CLOSE need be done, even though multiple OPENs were completed. When such an OPEN is done, checking of share reservations for the new OPEN proceeds normally, with no exception for the existing OPEN held by the same lockowner. If the underlying filesystem at the server is only accessible in a @@ -8206,24 +11266,24 @@ calls do not include the createattrs field. Conversely, if createattrs is specified, and includes owner or group (or corresponding ACEs) that the principal in the RPC call's credentials does not have authorization to create files for, then the server may return NFS4ERR_PERM. In the case of a OPEN which specifies a size of zero (e.g., truncation) and the file has named attributes, the named attributes are left as is. They are not removed. -14.18.6. IMPLEMENTATION +15.18.6. IMPLEMENTATION The OPEN operation contains support for EXCLUSIVE create. The - mechanism is similar to the support in NFS version 3 [13]. As in NFS + mechanism is similar to the support in NFS version 3 [14]. As in NFS version 3, this mechanism provides reliable exclusive creation. Exclusive create is invoked when the how parameter is EXCLUSIVE. In this case, the client provides a verifier that can reasonably be expected to be unique. A combination of a client identifier, perhaps the client network address, and a unique number generated by the client, perhaps the RPC transaction identifier, may be appropriate. If the object does not exist, the server creates the object and stores the verifier in stable storage. For filesystems that do not provide a mechanism for the storage of arbitrary file attributes, the @@ -8294,170 +11354,110 @@ version 4 protocol does not impose any requirement that READs and WRITEs issued for an open file have the same credentials as the OPEN itself, the server still must do appropriate access checking on the READs and WRITEs themselves. If the component provided to OPEN is a symbolic link, the error NFS4ERR_SYMLINK will be returned to the client. If the current filehandle is not a directory, the error NFS4ERR_NOTDIR will be returned. -14.18.7. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_ATTRNOTSUPP - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADOWNER - NFS4ERR_BAD_SEQID - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXIST - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_IO - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NOTDIR - NFS4ERR_NOTSUPP - NFS4ERR_NO_GRACE - NFS4ERR_PERM - NFS4ERR_RECLAIM_BAD - NFS4ERR_RECLAIM_CONFLICT - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_SHARE_DENIED - NFS4ERR_STALE - NFS4ERR_STALE_CLIENTID - NFS4ERR_SYMLINK - NFS4ERR_WRONGSEC - -14.19. Operation 19: OPENATTR - Open Named Attribute Directory +15.19. Operation 19: OPENATTR - Open Named Attribute Directory -14.19.1. SYNOPSIS +15.19.1. SYNOPSIS (cfh) createdir -> (cfh) -14.19.2. ARGUMENT +15.19.2. ARGUMENT struct OPENATTR4args { /* CURRENT_FH: object */ bool createdir; }; -14.19.3. RESULT +15.19.3. RESULT struct OPENATTR4res { /* CURRENT_FH: named attr directory */ nfsstat4 status; }; -14.19.4. DESCRIPTION +15.19.4. DESCRIPTION The OPENATTR operation is used to obtain the filehandle of the named attribute directory associated with the current filehandle. The result of the OPENATTR will be a filehandle to an object of type NF4ATTRDIR. From this filehandle, READDIR and LOOKUP operations can be used to obtain filehandles for the various named attributes associated with the original filesystem object. Filehandles returned within the named attribute directory will have a type of NF4NAMEDATTR. The createdir argument allows the client to signify if a named attribute directory should be created as a result of the OPENATTR operation. Some clients may use the OPENATTR operation with a value of FALSE for createdir to determine if any named attributes exist for the object. If none exist, then NFS4ERR_NOENT will be returned. If createdir has a value of TRUE and no named attribute directory exists, one is created. The creation of a named attribute directory assumes that the server has implemented named attribute support in this fashion and is not required to do so by this definition. -14.19.5. IMPLEMENTATION +15.19.5. IMPLEMENTATION If the server does not support named attributes for the current filehandle, an error of NFS4ERR_NOTSUPP will be returned to the client. -14.19.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_FHEXPIRED - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NOTSUPP - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.20. Operation 20: OPEN_CONFIRM - Confirm Open +15.20. Operation 20: OPEN_CONFIRM - Confirm Open -14.20.1. SYNOPSIS +15.20.1. SYNOPSIS (cfh), seqid, stateid-> stateid -14.20.2. ARGUMENT +15.20.2. ARGUMENT struct OPEN_CONFIRM4args { /* CURRENT_FH: opened file */ stateid4 open_stateid; seqid4 seqid; }; -14.20.3. RESULT +15.20.3. RESULT struct OPEN_CONFIRM4resok { stateid4 open_stateid; }; union OPEN_CONFIRM4res switch (nfsstat4 status) { case NFS4_OK: OPEN_CONFIRM4resok resok4; default: void; }; -14.20.4. DESCRIPTION +15.20.4. DESCRIPTION This operation is used to confirm the sequence id usage for the first time that a open_owner is used by a client. The stateid returned from the OPEN operation is used as the argument for this operation along with the next sequence id for the open_owner. The sequence id passed to the OPEN_CONFIRM must be 1 (one) greater than the seqid passed to the OPEN operation from which the open_confirm value was obtained. If the server receives an unexpected sequence id with respect to the original open, then the server assumes that the client will not confirm the original OPEN and all state associated with the original OPEN is released by the server. On success, the current filehandle retains its value. -14.20.5. IMPLEMENTATION +15.20.5. IMPLEMENTATION A given client might generate many open_owner4 data structures for a given clientid. The client will periodically either dispose of its open_owner4s or stop using them for indefinite periods of time. The latter situation is why the NFS version 4 protocol does not have an explicit operation to exit an open_owner4: such an operation is of no use in that situation. Instead, to avoid unbounded memory use, the server needs to implement a strategy for disposing of open_owner4s that have no current lock, open, or delegation state for any files and have not been used recently. The time period used to determine @@ -8465,26 +11465,25 @@ time period should certainly be no less than the lease time plus any grace period the server wishes to implement beyond a lease time. The OPEN_CONFIRM operation allows the server to safely dispose of unused open_owner4 data structures. In the case that a client issues an OPEN operation and the server no longer has a record of the open_owner4, the server needs to ensure that this is a new OPEN and not a replay or retransmission. Servers must not require confirmation on OPENs that grant delegations - or are doing reclaim operations. See Section 8.1.8 "Use of Open - Confirmation" for details. The server can easily avoid this by - noting whether it has disposed of one open_owner4 for the given - clientid. If the server does not support delegation, it might simply - maintain a single bit that notes whether any open_owner4 (for any - client) has been disposed of. + or are doing reclaim operations. See Section 9.1.8 for details. The + server can easily avoid this by noting whether it has disposed of one + open_owner4 for the given clientid. If the server does not support + delegation, it might simply maintain a single bit that notes whether + any open_owner4 (for any client) has been disposed of. The server must hold unconfirmed OPEN state until one of three events occur. First, the client sends an OPEN_CONFIRM request with the appropriate sequence id and stateid within the lease period. In this case, the OPEN state on the server goes to confirmed, and the open_owner4 on the server is fully established. Second, the client sends another OPEN request with a sequence id that is incorrect for the open_owner4 (out of sequence). In this case, the server assumes the second OPEN request is valid and the first one @@ -8502,289 +11501,229 @@ a stateid but the operation is not OPEN, or it is OPEN_CONFIRM but with the wrong stateid? Then, even if the seqid is correct, the server returns NFS4ERR_BAD_STATEID, because the server assumes the operation is a replay: if the server has no established OPEN state, then there is no way, for example, a LOCK operation could be valid. Third, neither of the two aforementioned events occur for the open_owner4 within the lease period. In this case, the OPEN state is canceled and disposal of the open_owner4 can occur. -14.20.6. ERRORS - - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_SEQID - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_OLD_STATEID - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.21. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access +15.21. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access -14.21.1. SYNOPSIS +15.21.1. SYNOPSIS (cfh), stateid, seqid, access, deny -> stateid -14.21.2. ARGUMENT +15.21.2. ARGUMENT struct OPEN_DOWNGRADE4args { /* CURRENT_FH: opened file */ stateid4 open_stateid; seqid4 seqid; uint32_t share_access; uint32_t share_deny; }; -14.21.3. RESULT +15.21.3. RESULT struct OPEN_DOWNGRADE4resok { stateid4 open_stateid; }; union OPEN_DOWNGRADE4res switch(nfsstat4 status) { case NFS4_OK: OPEN_DOWNGRADE4resok resok4; default: void; }; -14.21.4. DESCRIPTION +15.21.4. DESCRIPTION This operation is used to adjust the share_access and share_deny bits for a given open. This is necessary when a given openowner opens the same file multiple times with different share_access and share_deny flags. In this situation, a close of one of the opens may change the appropriate share_access and share_deny flags to remove bits associated with opens no longer in effect. The share_access and share_deny bits specified in this operation replace the current ones for the specified open file. The share_access and share_deny bits specified must be exactly equal to the union of the share_access and share_deny bits specified for some subset of the OPENs in effect for current openowner on the current file. If that constraint is not respected, the error NFS4ERR_INVAL should be returned. Since share_access and share_deny bits are subsets of those already granted, it is not possible for this request to be denied because of conflicting share reservations. On success, the current filehandle retains its value. -14.21.5. ERRORS - - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_SEQID - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_OLD_STATEID - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.22. Operation 22: PUTFH - Set Current Filehandle +15.22. Operation 22: PUTFH - Set Current Filehandle -14.22.1. SYNOPSIS +15.22.1. SYNOPSIS filehandle -> (cfh) -14.22.2. ARGUMENT +15.22.2. ARGUMENT struct PUTFH4args { nfs_fh4 object; }; -14.22.3. RESULT +15.22.3. RESULT struct PUTFH4res { /* CURRENT_FH: */ nfsstat4 status; }; -14.22.4. DESCRIPTION +15.22.4. DESCRIPTION Replaces the current filehandle with the filehandle provided as an argument. If the security mechanism used by the requester does not meet the requirements of the filehandle provided to this operation, the server MUST return NFS4ERR_WRONGSEC. -14.22.5. IMPLEMENTATION +15.22.5. IMPLEMENTATION Commonly used as the first operator in an NFS request to set the context for following operations. -14.22.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_FHEXPIRED - NFS4ERR_MOVED - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_WRONGSEC - -14.23. Operation 23: PUTPUBFH - Set Public Filehandle +15.23. Operation 23: PUTPUBFH - Set Public Filehandle -14.23.1. SYNOPSIS +15.23.1. SYNOPSIS - -> (cfh) -14.23.2. ARGUMENT +15.23.2. ARGUMENT void; -14.23.3. RESULT +15.23.3. RESULT struct PUTPUBFH4res { /* CURRENT_FH: public fh */ nfsstat4 status; }; -14.23.4. DESCRIPTION +15.23.4. DESCRIPTION Replaces the current filehandle with the filehandle that represents the public filehandle of the server's name space. This filehandle may be different from the "root" filehandle which may be associated with some other directory on the server. - The public filehandle represents the concepts embodied in [22], [23], - [29]. The intent for NFS version 4 is that the public filehandle + The public filehandle represents the concepts embodied in [23], [24], + [31]. The intent for NFS version 4 is that the public filehandle (represented by the PUTPUBFH operation) be used as a method of providing WebNFS server compatibility with NFS versions 2 and 3. The public filehandle and the root filehandle (represented by the PUTROOTFH operation) should be equivalent. If the public and root filehandles are not equivalent, then the public filehandle MUST be a descendant of the root filehandle. -14.23.5. IMPLEMENTATION +15.23.5. IMPLEMENTATION Used as the first operator in an NFS request to set the context for following operations. With the NFS version 2 and 3 public filehandle, the client is able to specify whether the path name provided in the LOOKUP should be evaluated as either an absolute path relative to the server's root or - relative to the public filehandle. [29] contains further discussion + relative to the public filehandle. [31] contains further discussion of the functionality. With NFS version 4, that type of specification is not directly available in the LOOKUP operation. The reason for this is because the component separators needed to specify absolute vs. relative are not allowed in NFS version 4. Therefore, the client is responsible for constructing its request such that the use of either PUTROOTFH or PUTPUBFH are used to signify absolute or relative evaluation of an NFS URL respectively. - Note that there are warnings mentioned in [29] with respect to the + Note that there are warnings mentioned in [31] with respect to the use of absolute evaluation and the restrictions the server may place on that evaluation with respect to how much of its namespace has been made available. These same warnings apply to NFS version 4. It is likely, therefore that because of server implementation details, an NFS version 3 absolute public filehandle lookup may behave differently than an NFS version 4 absolute resolution. - There is a form of security negotiation as described in [30] that + There is a form of security negotiation as described in [32] that uses the public filehandle a method of employing SNEGO. This method is not available with NFS version 4 as filehandles are not overloaded with special meaning and therefore do not provide the same framework as NFS versions 2 and 3. Clients should therefore use the security negotiation mechanisms described in this RFC. -14.23.6. ERRORS - - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_WRONGSEC - -14.24. Operation 24: PUTROOTFH - Set Root Filehandle +15.24. Operation 24: PUTROOTFH - Set Root Filehandle -14.24.1. SYNOPSIS +15.24.1. SYNOPSIS - -> (cfh) -14.24.2. ARGUMENT +15.24.2. ARGUMENT void; -14.24.3. RESULT +15.24.3. RESULT struct PUTROOTFH4res { /* CURRENT_FH: root fh */ nfsstat4 status; }; -14.24.4. DESCRIPTION +15.24.4. DESCRIPTION Replaces the current filehandle with the filehandle that represents the root of the server's name space. From this filehandle a LOOKUP operation can locate any other filehandle on the server. This filehandle may be different from the "public" filehandle which may be associated with some other directory on the server. -14.24.5. IMPLEMENTATION +15.24.5. IMPLEMENTATION Commonly used as the first operator in an NFS request to set the context for following operations. -14.24.6. ERRORS - - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_WRONGSEC - -14.25. Operation 25: READ - Read from File +15.25. Operation 25: READ - Read from File -14.25.1. SYNOPSIS +15.25.1. SYNOPSIS (cfh), stateid, offset, count -> eof, data -14.25.2. ARGUMENT +15.25.2. ARGUMENT struct READ4args { /* CURRENT_FH: file */ stateid4 stateid; offset4 offset; count4 count; }; -14.25.3. RESULT +15.25.3. RESULT struct READ4resok { bool eof; opaque data<>; }; union READ4res switch (nfsstat4 status) { case NFS4_OK: READ4resok resok4; default: void; }; -14.25.4. DESCRIPTION +15.25.4. DESCRIPTION The READ operation reads data from the regular file identified by the current filehandle. The client provides an offset of where the READ is to start and a count of how many bytes are to be read. An offset of 0 (zero) means to read data starting at the beginning of the file. If offset is greater than or equal to the size of the file, the status, NFS4_OK, is returned with a data length set to 0 (zero) and eof is set to TRUE. The READ is subject to access permissions checking. @@ -8814,21 +11753,21 @@ NFS4ERR_INVAL is returned. For a READ with a stateid value of all bits 0, the server MAY allow the READ to be serviced subject to mandatory file locks or the current share deny modes for the file. For a READ with a stateid value of all bits 1, the server MAY allow READ operations to bypass locking checks at the server. On success, the current filehandle retains its value. -14.25.5. IMPLEMENTATION +15.25.5. IMPLEMENTATION It is possible for the server to return fewer than count bytes of data. If the server returns less than the count requested and eof is set to FALSE, the client should issue another READ to get the remaining data. A server may return less data than requested under several circumstances. The file may have been truncated by another client or perhaps on the server itself, changing the file size from what the requesting client believes to be the case. This would reduce the actual amount of data available to the client. It is possible that the server may back off the transfer size and reduce @@ -8836,65 +11775,39 @@ necessitating a smaller read return. If mandatory file locking is on for the file, and if the region corresponding to the data to be read from file is write locked by an owner not associated the stateid, the server will return the NFS4ERR_LOCKED error. The client should try to get the appropriate read record lock via the LOCK operation before re-attempting the READ. When the READ completes, the client should release the record lock via LOCKU. -14.25.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_EXPIRED - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_IO - NFS4ERR_INVAL - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCKED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NXIO - NFS4ERR_OLD_STATEID - NFS4ERR_OPENMODE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.26. Operation 26: READDIR - Read Directory +15.26. Operation 26: READDIR - Read Directory -14.26.1. SYNOPSIS +15.26.1. SYNOPSIS (cfh), cookie, cookieverf, dircount, maxcount, attr_request -> cookieverf { cookie, name, attrs } -14.26.2. ARGUMENT +15.26.2. ARGUMENT struct READDIR4args { /* CURRENT_FH: directory */ nfs_cookie4 cookie; verifier4 cookieverf; count4 dircount; count4 maxcount; bitmap4 attr_request; }; -14.26.3. RESULT +15.26.3. RESULT struct entry4 { nfs_cookie4 cookie; component4 name; fattr4 attrs; entry4 *nextentry; }; struct dirlist4 { entry4 *entries; @@ -8906,21 +11819,21 @@ dirlist4 reply; }; union READDIR4res switch (nfsstat4 status) { case NFS4_OK: READDIR4resok resok4; default: void; }; -14.26.4. DESCRIPTION +15.26.4. DESCRIPTION The READDIR operation retrieves a variable number of entries from a filesystem directory and returns client requested attributes for each entry along with information to allow the client to request additional directory entries in a subsequent READDIR. The arguments contain a cookie value that represents where the READDIR should start within the directory. A value of 0 (zero) for the cookie is used to start reading at the beginning of the directory. For subsequent READDIR requests, the client specifies a @@ -8985,21 +11898,21 @@ values when combining the server's response and local representations to enable a fully formed UNIX directory presentation to the application. For READDIR arguments, cookie values of 1 and 2 should not be used and for READDIR results cookie values of 0, 1, and 2 should not be returned. On success, the current filehandle retains its value. -14.26.5. IMPLEMENTATION +15.26.5. IMPLEMENTATION The server's filesystem directory representations can differ greatly. A client's programming interfaces may also be bound to the local operating environment in a way that does not translate well into the NFS protocol. Therefore the use of the dircount and maxcount fields are provided to allow the client the ability to provide guidelines to the server. If the client is aggressive about attribute collection during a READDIR, the server has an idea of how to limit the encoded response. The dircount field provides a hint on the number of entries based solely on the names of the directory entries. Since it @@ -9022,156 +11935,122 @@ to provide the appropriate response to the client. This prevents the case where the server may accept a cookie value but the underlying directory has changed and the response is invalid from the client's context of its previous READDIR. Since some servers will not be returning "." and ".." entries as has been done with previous versions of the NFS protocol, the client that requires these entries be present in READDIR responses must fabricate them. -14.26.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_BAD_COOKIE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTDIR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_TOOSMALL - -14.27. Operation 27: READLINK - Read Symbolic Link +15.27. Operation 27: READLINK - Read Symbolic Link -14.27.1. SYNOPSIS +15.27.1. SYNOPSIS (cfh) -> linktext -14.27.2. ARGUMENT +15.27.2. ARGUMENT /* CURRENT_FH: symlink */ void; -14.27.3. RESULT +15.27.3. RESULT struct READLINK4resok { linktext4 link; }; union READLINK4res switch (nfsstat4 status) { case NFS4_OK: READLINK4resok resok4; default: void; }; -14.27.4. DESCRIPTION +15.27.4. DESCRIPTION READLINK reads the data associated with a symbolic link. The data is a UTF-8 string that is opaque to the server. That is, whether created by an NFS client or created locally on the server, the data in a symbolic link is not interpreted when created, but is simply stored. On success, the current filehandle retains its value. -14.27.5. IMPLEMENTATION +15.27.5. IMPLEMENTATION A symbolic link is nominally a pointer to another file. The data is not necessarily interpreted by the server, just stored in the file. It is possible for a client implementation to store a path name that is not meaningful to the server operating system in a symbolic link. A READLINK operation returns the data to the client for interpretation. If different implementations want to share access to symbolic links, then they must agree on the interpretation of the data in the symbolic link. The READLINK operation is only allowed on objects of type NF4LNK. The server should return the error, NFS4ERR_INVAL, if the object is not of type, NF4LNK. -14.27.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADHANDLE - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_ISDIR - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTSUPP - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.28. Operation 28: REMOVE - Remove Filesystem Object +15.28. Operation 28: REMOVE - Remove Filesystem Object -14.28.1. SYNOPSIS +15.28.1. SYNOPSIS (cfh), filename -> change_info -14.28.2. ARGUMENT +15.28.2. ARGUMENT struct REMOVE4args { /* CURRENT_FH: directory */ component4 target; }; -14.28.3. RESULT +15.28.3. RESULT struct REMOVE4resok { change_info4 cinfo; }; union REMOVE4res switch (nfsstat4 status) { case NFS4_OK: REMOVE4resok resok4; default: void; }; -14.28.4. DESCRIPTION +15.28.4. DESCRIPTION - The REMOVE operation removes (deletes) a directory entry named by + The REMOVE operation removes (deletes) a directory entry M named by filename from the directory corresponding to the current filehandle. If the entry in the directory was the last reference to the corresponding filesystem object, the object may be destroyed. For the directory where the filename was removed, the server returns change_info4 information in cinfo. With the atomic field of the change_info4 struct, the server will indicate if the before and after change attributes were obtained atomically with respect to the removal. - If the target has a length of 0 (zero), or if target does not obey - the UTF-8 definition, the error NFS4ERR_INVAL will be returned. + If the target is of zero length, NFS4ERR_INVAL will be returned. The + target is also subject to the normal UTF-8, character support, and + name checks. See Section 12.3 for further discussion. On success, the current filehandle retains its value. -14.28.5. IMPLEMENTATION +15.28.5. IMPLEMENTATION NFS versions 2 and 3 required a different operator RMDIR for directory removal and REMOVE for non-directory removal. This allowed clients to skip checking the file type when being passed a non- directory delete system call (e.g., unlink() in POSIX) to remove a directory, as well as the converse (e.g., a rmdir() on a non- directory) because they knew the server would check the file type. - NFS version 4 REMOVE can be used to delete any directory entry independent of its file type. The implementor of an NFS version 4 client's entry points from the unlink() and rmdir() system calls should first check the file type against the types the system call is allowed to remove before issuing a REMOVE. Alternatively, the implementor can produce a COMPOUND call that includes a LOOKUP/VERIFY sequence to verify the file type before a REMOVE operation in the same COMPOUND call. The concept of last reference is server specific. However, if the @@ -9191,112 +12070,89 @@ o The server SHOULD NOT delete the file's directory entry if the file was opened with OPEN4_SHARE_DENY_WRITE or OPEN4_SHARE_DENY_BOTH. o If the file was not opened with OPEN4_SHARE_DENY_WRITE or OPEN4_SHARE_DENY_BOTH, the server SHOULD delete the file's directory entry. However, until last CLOSE of the file, the server MAY continue to allow access to the file via its filehandle. -14.28.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_FILE_OPEN - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTDIR - NFS4ERR_NOTEMPTY - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.29. Operation 29: RENAME - Rename Directory Entry +15.29. Operation 29: RENAME - Rename Directory Entry -14.29.1. SYNOPSIS +15.29.1. SYNOPSIS (sfh), oldname, (cfh), newname -> source_change_info, target_change_info -14.29.2. ARGUMENT +15.29.2. ARGUMENT struct RENAME4args { /* SAVED_FH: source directory */ component4 oldname; /* CURRENT_FH: target directory */ component4 newname; }; -14.29.3. RESULT +15.29.3. RESULT struct RENAME4resok { change_info4 source_cinfo; change_info4 target_cinfo; }; union RENAME4res switch (nfsstat4 status) { case NFS4_OK: RENAME4resok resok4; default: void; }; -14.29.4. DESCRIPTION +15.29.4. DESCRIPTION The RENAME operation renames the object identified by oldname in the source directory corresponding to the saved filehandle, as set by the SAVEFH operation, to newname in the target directory corresponding to the current filehandle. The operation is required to be atomic to the client. Source and target directories must reside on the same filesystem on the server. On success, the current filehandle will continue to be the target directory. If the target directory already contains an entry with the name, newname, the source object must be compatible with the target: either both are non-directories or both are directories and the target must be empty. If compatible, the existing target is removed before the - rename occurs (See Section 14.28.5 IMPLEMENTATION of Section 14.28 - "Operation 28: REMOVE - Remove Filesystem Object" for client and - server actions whenever a target is removed). If they are not - compatible or if the target is a directory but not empty, the server - will return the error, NFS4ERR_EXIST. + rename occurs (See Section 15.28 for client and server actions + whenever a target is removed). If they are not compatible or if the + target is a directory but not empty, the server will return the + error, NFS4ERR_EXIST. If oldname and newname both refer to the same file (they might be hard links of each other), then RENAME should perform no action and return success. For both directories involved in the RENAME, the server returns change_info4 information. With the atomic field of the change_info4 struct, the server will indicate if the before and after change attributes were obtained atomically with respect to the rename. If the oldname refers to a named attribute and the saved and current filehandles refer to different filesystem objects, the server will return NFS4ERR_XDEV just as if the saved and current filehandles represented directories on different filesystems. - If the oldname or newname has a length of 0 (zero), or if oldname or - newname does not obey the UTF-8 definition, the error NFS4ERR_INVAL - will be returned. + If the oldname or newname is of zero length, NFS4ERR_INVAL will be + returned. The oldname and newname are also subject to the normal + UTF-8, character support, and name checks. See Section 12.3 for + further discussion. -14.29.5. IMPLEMENTATION +15.29.5. IMPLEMENTATION The RENAME operation must be atomic to the client. The statement "source and target directories must reside on the same filesystem on the server" means that the fsid fields in the attributes for the directories are the same. If they reside on different filesystems, the error, NFS4ERR_XDEV, is returned. Based on the value of the fh_expire_type attribute for the object, the filehandle may or may not expire on a RENAME. However, server implementors are strongly encouraged to attempt to keep filehandles @@ -9304,75 +12160,47 @@ On some servers, the file names "." and ".." are illegal as either oldname or newname, and will result in the error NFS4ERR_BADNAME. In addition, on many servers the case of oldname or newname being an alias for the source directory will be checked for. Such servers will return the error NFS4ERR_INVAL in these cases. If either of the source or target filehandles are not directories, the server will return NFS4ERR_NOTDIR. -14.29.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXIST - NFS4ERR_FHEXPIRED - NFS4ERR_FILE_OPEN - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NOTDIR - NFS4ERR_NOTEMPTY - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_WRONGSEC - NFS4ERR_XDEV - -14.30. Operation 30: RENEW - Renew a Lease +15.30. Operation 30: RENEW - Renew a Lease -14.30.1. SYNOPSIS +15.30.1. SYNOPSIS clientid -> () -14.30.2. ARGUMENT +15.30.2. ARGUMENT struct RENEW4args { clientid4 clientid; }; -14.30.3. RESULT +15.30.3. RESULT struct RENEW4res { nfsstat4 status; }; -14.30.4. DESCRIPTION +15.30.4. DESCRIPTION The RENEW operation is used by the client to renew leases which it currently holds at a server. In processing the RENEW request, the server renews all leases associated with the client. The associated leases are determined by the clientid provided via the SETCLIENTID operation. -14.30.5. IMPLEMENTATION +15.30.5. IMPLEMENTATION When the client holds delegations, it needs to use RENEW to detect when the server has determined that the callback path is down. When the server has made such a determination, only the RENEW operation will renew the lease on delegations. If the server determines the callback path is down, it returns NFS4ERR_CB_PATH_DOWN. Even though it returns NFS4ERR_CB_PATH_DOWN, the server MUST renew the lease on the record locks and share reservations that the client has established on the server. If for some reason the lock and share reservation lease cannot be renewed, then the server MUST return an @@ -9390,133 +12218,101 @@ o The client uses any principal, RPC security flavor mechanism and service combination that currently has an OPEN file on the server. I.e., the same principal had a successful OPEN operation, the file is still open by that principal, and the flavor, mechanism, and service of RENEW match that of the previous OPEN. The server MUST reject a RENEW that does not use one the aforementioned algorithms, with the error NFS4ERR_ACCESS. -14.30.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADXDR - NFS4ERR_CB_PATH_DOWN - NFS4ERR_EXPIRED - NFS4ERR_LEASE_MOVED - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE_CLIENTID - -14.31. Operation 31: RESTOREFH - Restore Saved Filehandle +15.31. Operation 31: RESTOREFH - Restore Saved Filehandle -14.31.1. SYNOPSIS +15.31.1. SYNOPSIS (sfh) -> (cfh) -14.31.2. ARGUMENT +15.31.2. ARGUMENT /* SAVED_FH: */ void; -14.31.3. RESULT +15.31.3. RESULT struct RESTOREFH4res { /* CURRENT_FH: value of saved fh */ nfsstat4 status; }; -14.31.4. DESCRIPTION +15.31.4. DESCRIPTION Set the current filehandle to the value in the saved filehandle. If there is no saved filehandle then return the error NFS4ERR_RESTOREFH. -14.31.5. IMPLEMENTATION +15.31.5. IMPLEMENTATION Operations like OPEN and LOOKUP use the current filehandle to represent a directory and replace it with a new filehandle. Assuming the previous filehandle was saved with a SAVEFH operator, the previous filehandle can be restored as the current filehandle. This is commonly used to obtain post-operation attributes for the directory, e.g., PUTFH (directory filehandle) SAVEFH GETATTR attrbits (pre-op dir attrs) CREATE optbits "foo" attrs GETATTR attrbits (file attributes) RESTOREFH GETATTR attrbits (post-op dir attrs) -14.31.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_FHEXPIRED - NFS4ERR_MOVED - NFS4ERR_RESOURCE - NFS4ERR_RESTOREFH - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_WRONGSEC - -14.32. Operation 32: SAVEFH - Save Current Filehandle +15.32. Operation 32: SAVEFH - Save Current Filehandle -14.32.1. SYNOPSIS +15.32.1. SYNOPSIS (cfh) -> (sfh) -14.32.2. ARGUMENT +15.32.2. ARGUMENT /* CURRENT_FH: */ void; -14.32.3. RESULT +15.32.3. RESULT struct SAVEFH4res { /* SAVED_FH: value of current fh */ nfsstat4 status; }; -14.32.4. DESCRIPTION +15.32.4. DESCRIPTION Save the current filehandle. If a previous filehandle was saved then it is no longer accessible. The saved filehandle can be restored as the current filehandle with the RESTOREFH operator. On success, the current filehandle retains its value. -14.32.5. IMPLEMENTATION -14.32.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_FHEXPIRED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE +15.32.5. IMPLEMENTATION -14.33. Operation 33: SECINFO - Obtain Available Security +15.33. Operation 33: SECINFO - Obtain Available Security -14.33.1. SYNOPSIS +15.33.1. SYNOPSIS (cfh), name -> { secinfo } -14.33.2. ARGUMENT +15.33.2. ARGUMENT struct SECINFO4args { /* CURRENT_FH: directory */ component4 name; }; -14.33.3. RESULT +15.33.3. RESULT /* * From RFC 2203 */ enum rpc_gss_svc_t { RPC_GSS_SVC_NONE = 1, RPC_GSS_SVC_INTEGRITY = 2, RPC_GSS_SVC_PRIVACY = 3 }; @@ -9536,21 +12332,21 @@ typedef secinfo4 SECINFO4resok<>; union SECINFO4res switch (nfsstat4 status) { case NFS4_OK: SECINFO4resok resok4; default: void; }; -14.33.4. DESCRIPTION +15.33.4. DESCRIPTION The SECINFO operation is used by the client to obtain a list of valid RPC authentication flavors for a specific directory filehandle, file name pair. SECINFO should apply the same access methodology used for LOOKUP when evaluating the name. Therefore, if the requester does not have the appropriate access to LOOKUP the name then SECINFO must behave the same way and return NFS4ERR_ACCESS. The result will contain an array which represents the security mechanisms available, with an order corresponding to server's @@ -9567,21 +12363,21 @@ defined in [6]), the quality of protection (as defined in [6]) and the service type (as defined in [4]). It is possible for SECINFO to return multiple entries with flavor equal to RPCSEC_GSS with different security triple values. On success, the current filehandle retains its value. If the name has a length of 0 (zero), or if name does not obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned. -14.33.5. IMPLEMENTATION +15.33.5. IMPLEMENTATION The SECINFO operation is expected to be used by the NFS client when the error value of NFS4ERR_WRONGSEC is returned from another NFS operation. This signifies to the client that the server's security policy is different from what the client is currently using. At this point, the client is expected to obtain a list of possible security flavors and choose what best suits its policies. As mentioned, the server's security policies will determine when a client request receives NFS4ERR_WRONGSEC. The operations which may @@ -9624,63 +12420,45 @@ whatever security form the client requests and the server supports, since the risks of doing so are on the client. The READDIR operation will not directly return the NFS4ERR_WRONGSEC error. However, if the READDIR request included a request for attributes, it is possible that the READDIR request's security triple does not match that of a directory entry. If this is the case and the client has requested the rdattr_error attribute, the server will return the NFS4ERR_WRONGSEC error in rdattr_error for the entry. - See Section 16 "Security Considerations" for a discussion on the - recommendations for security flavor used by SECINFO. - -14.33.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADNAME - NFS4ERR_BADXDR - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_MOVED - NFS4ERR_NAMETOOLONG - NFS4ERR_NOENT - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTDIR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE + See Section 17 for a discussion on the recommendations for security + flavor used by SECINFO. -14.34. Operation 34: SETATTR - Set Attributes +15.34. Operation 34: SETATTR - Set Attributes -14.34.1. SYNOPSIS +15.34.1. SYNOPSIS (cfh), stateid, attrmask, attr_vals -> attrsset -14.34.2. ARGUMENT +15.34.2. ARGUMENT struct SETATTR4args { /* CURRENT_FH: target object */ stateid4 stateid; fattr4 obj_attributes; }; -14.34.3. RESULT +15.34.3. RESULT struct SETATTR4res { nfsstat4 status; bitmap4 attrsset; }; -14.34.4. DESCRIPTION +15.34.4. DESCRIPTION The SETATTR operation changes one or more of the attributes of a filesystem object. The new attributes are specified with a bitmap and the attributes that follow the bitmap in bit order. The stateid argument for SETATTR is used to provide file locking context that is necessary for SETATTR requests that set the size attribute. Since setting the size attribute modifies the file's data, it has the same locking requirements as a corresponding WRITE. Any SETATTR that sets the size attribute is incompatible with a share @@ -9693,21 +12471,21 @@ specified. When the file size attribute is not set, the special stateid consisting of all bits zero should be passed. On either success or failure of the operation, the server will return the attrsset bitmask to represent what (if any) attributes were successfully set. The attrsset in the response is a subset of the bitmap4 that is part of the obj_attributes in the argument. On success, the current filehandle retains its value. -14.34.5. IMPLEMENTATION +15.34.5. IMPLEMENTATION If the request specifies the owner attribute to be set, the server should allow the operation to succeed if the current owner of the object matches the value specified in the request. Some servers may be implemented in a way as to prohibit the setting of the owner attribute unless the requester has privilege to do so. If the server is lenient in this one case of matching owner values, the client implementation may be simplified in cases of creation of an object followed by a SETATTR. @@ -9754,83 +12532,51 @@ executing such a request. If the server does not support an attribute as requested by the client, the server should return NFS4ERR_ATTRNOTSUPP. A mask of the attributes actually set is returned by SETATTR in all cases. That mask must not include attributes bits not requested to be set by the client, and must be equal to the mask of attributes requested to be set only if the SETATTR completes without error. -14.34.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_ATTRNOTSUPP - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADOWNER - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXPIRED - NFS4ERR_FBIG - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_ISDIR - NFS4ERR_LOCKED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_OLD_STATEID - NFS4ERR_OPENMODE - NFS4ERR_PERM - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.35. Operation 35: SETCLIENTID - Negotiate Clientid +15.35. Operation 35: SETCLIENTID - Negotiate Clientid -14.35.1. SYNOPSIS +15.35.1. SYNOPSIS client, callback, callback_ident -> clientid, setclientid_confirm -14.35.2. ARGUMENT +15.35.2. ARGUMENT struct SETCLIENTID4args { nfs_client_id4 client; cb_client4 callback; uint32_t callback_ident; }; -14.35.3. RESULT +15.35.3. RESULT struct SETCLIENTID4resok { clientid4 clientid; verifier4 setclientid_confirm; }; union SETCLIENTID4res switch (nfsstat4 status) { case NFS4_OK: SETCLIENTID4resok resok4; case NFS4ERR_CLID_INUSE: clientaddr4 client_using; default: void; }; -14.35.4. DESCRIPTION +15.35.4. DESCRIPTION The client uses the SETCLIENTID operation to notify the server of its intention to use a particular client identifier, callback, and callback_ident for subsequent requests that entail creating lock, share reservation, and delegation state on the server. Upon successful completion the server will return a shorthand clientid which, if confirmed via a separate step, will be used in subsequent file locking and file open requests. Confirmation of the clientid must be done via the SETCLIENTID_CONFIRM operation to return the clientid and setclientid_confirm values, as verifiers, to the server. @@ -9843,21 +12589,21 @@ The callback information provided in this operation will be used if the client is provided an open delegation at a future point. Therefore, the client must correctly reflect the program and port numbers for the callback program at the time SETCLIENTID is used. The callback_ident value is used by the server on the callback. The client can leverage the callback_ident to eliminate the need for more than one callback RPC program number, while still being able to determine which server is initiating the callback. -14.35.5. IMPLEMENTATION +15.35.5. IMPLEMENTATION To understand how to implement SETCLIENTID, make the following notations. Let: x be the value of the client.id subfield of the SETCLIENTID4args structure. v be the value of the client.verifier subfield of the SETCLIENTID4args structure. @@ -9960,55 +12706,47 @@ The server returns { d, t }. The server awaits confirmation of { d, k } via SETCLIENTID_CONFIRM { d, t }. The server does NOT remove client (lock/share/ delegation) state for x. The server generates the clientid and setclientid_confirm values and must take care to ensure that these values are extremely unlikely to ever be regenerated. -14.35.6. ERRORS - - NFS4ERR_BADXDR - NFS4ERR_CLID_INUSE - NFS4ERR_INVAL - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - -14.36. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid +15.36. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid -14.36.1. SYNOPSIS +15.36.1. SYNOPSIS clientid, verifier -> - -14.36.2. ARGUMENT +15.36.2. ARGUMENT struct SETCLIENTID_CONFIRM4args { clientid4 clientid; verifier4 setclientid_confirm; }; -14.36.3. RESULT +15.36.3. RESULT struct SETCLIENTID_CONFIRM4res { nfsstat4 status; }; -14.36.4. DESCRIPTION +15.36.4. DESCRIPTION This operation is used by the client to confirm the results from a previous call to SETCLIENTID. The client provides the server supplied (from a SETCLIENTID response) clientid. The server responds with a simple status of success or failure. -14.36.5. IMPLEMENTATION +15.36.5. IMPLEMENTATION The client must use the SETCLIENTID_CONFIRM operation to confirm the following two distinct cases: o The client's use of a new shorthand client identifier (as returned from the server in the response to SETCLIENTID), a new callback value (as specified in the arguments to SETCLIENTID) and a new callback_ident (as specified in the arguments to SETCLIENTID) value. The client's use of SETCLIENTID_CONFIRM in this case also confirms the removal of any of the client's previous relevant @@ -10130,56 +12868,48 @@ confirm the clientid. SETCLIENTID_CONFIRM does not establish or renew a lease. However, if SETCLIENTID_CONFIRM removes relevant leased client state, and that state does not include existing delegations, the server MUST allow the client a period of time no less than the value of lease_time attribute, to reclaim, (via the CLAIM_DELEGATE_PREV claim type of the OPEN operation) its delegations before removing unreclaimed delegations. -14.36.6. ERRORS - - NFS4ERR_BADXDR - NFS4ERR_CLID_INUSE - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE_CLIENTID - -14.37. Operation 37: VERIFY - Verify Same Attributes +15.37. Operation 37: VERIFY - Verify Same Attributes -14.37.1. SYNOPSIS +15.37.1. SYNOPSIS (cfh), fattr -> - -14.37.2. ARGUMENT +15.37.2. ARGUMENT struct VERIFY4args { /* CURRENT_FH: object */ fattr4 obj_attributes; }; -14.37.3. RESULT +15.37.3. RESULT struct VERIFY4res { nfsstat4 status; }; -14.37.4. DESCRIPTION +15.37.4. DESCRIPTION The VERIFY operation is used to verify that attributes have a value assumed by the client before proceeding with following operations in the compound request. If any of the attributes do not match then the error NFS4ERR_NOT_SAME must be returned. The current filehandle retains its value after successful completion of the operation. -14.37.5. IMPLEMENTATION +15.37.5. IMPLEMENTATION One possible use of the VERIFY operation is the following compound sequence. With this the client is attempting to verify that the file being removed will match what the client expects to be removed. This sequence can help prevent the unintended deletion of a file. PUTFH (directory filehandle) LOOKUP (file name) VERIFY (filehandle == fh) PUTFH (directory filehandle) @@ -10191,75 +12921,58 @@ In the case that a recommended attribute is specified in the VERIFY operation and the server does not support that attribute for the filesystem object, the error NFS4ERR_ATTRNOTSUPP is returned to the client. When the attribute rdattr_error or any write-only attribute (e.g., time_modify_set) is specified, the error NFS4ERR_INVAL is returned to the client. -14.37.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ATTRNOTSUPP - NFS4ERR_BADCHAR - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_FHEXPIRED - NFS4ERR_INVAL - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOT_SAME - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - -14.38. Operation 38: WRITE - Write to File +15.38. Operation 38: WRITE - Write to File -14.38.1. SYNOPSIS +15.38.1. SYNOPSIS (cfh), stateid, offset, stable, data -> count, committed, writeverf -14.38.2. ARGUMENT +15.38.2. ARGUMENT enum stable_how4 { UNSTABLE4 = 0, DATA_SYNC4 = 1, FILE_SYNC4 = 2 }; struct WRITE4args { /* CURRENT_FH: file */ stateid4 stateid; offset4 offset; stable_how4 stable; opaque data<>; }; -14.38.3. RESULT +15.38.3. RESULT struct WRITE4resok { count4 count; stable_how4 committed; verifier4 writeverf; }; union WRITE4res switch (nfsstat4 status) { case NFS4_OK: WRITE4resok resok4; default: void; }; -14.38.4. DESCRIPTION +15.38.4. DESCRIPTION The WRITE operation is used to write data to a regular file. The target file is specified by the current filehandle. The offset specifies the offset where the data should be written. An offset of 0 (zero) specifies that the write should start at the beginning of the file. The count, as encoded as part of the opaque data parameter, represents the number of bytes of data that are to be written. If the count is 0 (zero), the WRITE will succeed and return a count of 0 (zero) subject to permissions checking. The server may choose to write fewer bytes than requested by the client. @@ -10325,21 +13038,21 @@ For a WRITE with a stateid value of all bits 0, the server MAY allow the WRITE to be serviced subject to mandatory file locks or the current share deny modes for the file. For a WRITE with a stateid value of all bits 1, the server MUST NOT allow the WRITE operation to bypass locking checks at the server and are treated exactly the same as if a stateid of all bits 0 were used. On success, the current filehandle retains its value. -14.38.5. IMPLEMENTATION +15.38.5. IMPLEMENTATION It is possible for the server to write fewer bytes of data than requested by the client. In this case, the server should not return an error unless no data was written at all. If the server writes less than the number of bytes specified, the client should issue another WRITE to write the remaining data. It is assumed that the act of writing data to a file will cause the time_modified of the file to be updated. However, the time_modified of the file should not be changed unless the contents of the file are @@ -10407,177 +13120,127 @@ attempted the WRITE. The reason is that since the stateid's owner had a read lock, the server either attempted to temporarily effectively upgrade this read lock to a write lock, or the server has no upgrade capability. If the server attempted to upgrade the read lock and failed, it is pointless for the client to re-attempt the upgrade via the LOCK operation, because there might be another client also trying to upgrade. If two clients are blocked trying upgrade the same lock, the clients deadlock. If the server has no upgrade capability, then it is pointless to try a LOCK operation to upgrade. -14.38.6. ERRORS - - NFS4ERR_ACCESS - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADHANDLE - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_DELAY - NFS4ERR_DQUOT - NFS4ERR_EXPIRED - NFS4ERR_FBIG - NFS4ERR_FHEXPIRED - NFS4ERR_GRACE - NFS4ERR_INVAL - NFS4ERR_IO - NFS4ERR_ISDIR - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCKED - NFS4ERR_MOVED - NFS4ERR_NOFILEHANDLE - NFS4ERR_NOSPC - NFS4ERR_NXIO - NFS4ERR_OLD_STATEID - NFS4ERR_OPENMODE - NFS4ERR_RESOURCE - NFS4ERR_ROFS - NFS4ERR_SERVERFAULT - NFS4ERR_STALE - NFS4ERR_STALE_STATEID - -14.39. Operation 39: RELEASE_LOCKOWNER - Release Lockowner State +15.39. Operation 39: RELEASE_LOCKOWNER - Release Lockowner State -14.39.1. SYNOPSIS +15.39.1. SYNOPSIS lockowner -> () -14.39.2. ARGUMENT +15.39.2. ARGUMENT struct RELEASE_LOCKOWNER4args { lock_owner4 lock_owner; }; -14.39.3. RESULT +15.39.3. RESULT struct RELEASE_LOCKOWNER4res { nfsstat4 status; }; -14.39.4. DESCRIPTION +15.39.4. DESCRIPTION This operation is used to notify the server that the lock_owner is no longer in use by the client. This allows the server to release cached state related to the specified lock_owner. If file locks, associated with the lock_owner, are held at the server, the error NFS4ERR_LOCKS_HELD will be returned and no further action will be taken. -14.39.5. IMPLEMENTATION +15.39.5. IMPLEMENTATION The client may choose to use this operation to ease the amount of server state that is held. Depending on behavior of applications at the client, it may be important for the client to use this operation since the server has certain obligations with respect to holding a reference to a lock_owner as long as the associated file is open. Therefore, if the client knows for certain that the lock_owner will no longer be used under the context of the associated open_owner4, it should use RELEASE_LOCKOWNER. -14.39.6. ERRORS - - NFS4ERR_ADMIN_REVOKED - NFS4ERR_BADXDR - NFS4ERR_EXPIRED - NFS4ERR_LEASE_MOVED - NFS4ERR_LOCKS_HELD - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - NFS4ERR_STALE_CLIENTID - -14.40. Operation 10044: ILLEGAL - Illegal operation +15.40. Operation 10044: ILLEGAL - Illegal operation -14.40.1. SYNOPSIS +15.40.1. SYNOPSIS -> () -14.40.2. ARGUMENT +15.40.2. ARGUMENT void; -14.40.3. RESULT +15.40.3. RESULT struct ILLEGAL4res { nfsstat4 status; }; -14.40.4. DESCRIPTION +15.40.4. DESCRIPTION This operation is a placeholder for encoding a result to handle the case of the client sending an operation code within COMPOUND that is - not supported. See the Section 14.2.4 COMPOUND procedure description - for more details. + not supported. See Section 15.2.4 for more details. The status field of ILLEGAL4res MUST be set to NFS4ERR_OP_ILLEGAL. -14.40.5. IMPLEMENTATION +15.40.5. IMPLEMENTATION A client will probably not send an operation with code OP_ILLEGAL but if it does, the response will be ILLEGAL4res just as it would be with any other invalid operation code. Note that if the server gets an illegal operation code that is not OP_ILLEGAL, and if the server checks for legal operation codes during the XDR decode phase, then the ILLEGAL4res would not be returned. -14.40.6. ERRORS - - NFS4ERR_OP_ILLEGAL - -15. NFS version 4 Callback Procedures +16. NFS version 4 Callback Procedures The procedures used for callbacks are defined in the following sections. In the interest of clarity, the terms "client" and "server" refer to NFS clients and servers, despite the fact that for an individual callback RPC, the sense of these terms would be precisely the opposite. -15.1. Procedure 0: CB_NULL - No Operation +16.1. Procedure 0: CB_NULL - No Operation -15.1.1. SYNOPSIS +16.1.1. SYNOPSIS -15.1.2. ARGUMENT +16.1.2. ARGUMENT void; -15.1.3. RESULT +16.1.3. RESULT void; -15.1.4. DESCRIPTION +16.1.4. DESCRIPTION Standard NULL procedure. Void argument, void response. Even though there is no direct functionality associated with this procedure, the server will use CB_NULL to confirm the existence of a path for RPCs from server to client. -15.1.5. ERRORS - - None. - -15.2. Procedure 1: CB_COMPOUND - Compound Operations +16.2. Procedure 1: CB_COMPOUND - Compound Operations -15.2.1. SYNOPSIS +16.2.1. SYNOPSIS compoundargs -> compoundres -15.2.2. ARGUMENT +16.2.2. ARGUMENT enum nfs_cb_opnum4 { OP_CB_GETATTR = 3, OP_CB_RECALL = 4, OP_CB_ILLEGAL = 10044 }; union nfs_cb_argop4 switch (unsigned argop) { case OP_CB_GETATTR: CB_GETATTR4args opcbgetattr; @@ -10578,257 +13241,227 @@ OP_CB_ILLEGAL = 10044 }; union nfs_cb_argop4 switch (unsigned argop) { case OP_CB_GETATTR: CB_GETATTR4args opcbgetattr; case OP_CB_RECALL: CB_RECALL4args opcbrecall; case OP_CB_ILLEGAL: void; }; + struct CB_COMPOUND4args { - utf8str_cs tag; + comptag4 tag; uint32_t minorversion; uint32_t callback_ident; nfs_cb_argop4 argarray<>; }; -15.2.3. RESULT +16.2.3. RESULT union nfs_cb_resop4 switch (unsigned resop) { case OP_CB_GETATTR: CB_GETATTR4res opcbgetattr; case OP_CB_RECALL: CB_RECALL4res opcbrecall; case OP_CB_ILLEGAL: CB_ILLEGAL4res opcbillegal; }; struct CB_COMPOUND4res { nfsstat4 status; - utf8str_cs tag; + comptag4 tag; nfs_cb_resop4 resarray<>; }; -15.2.4. DESCRIPTION +16.2.4. DESCRIPTION The CB_COMPOUND procedure is used to combine one or more of the callback procedures into a single RPC request. The main callback RPC program has two main procedures: CB_NULL and CB_COMPOUND. All other operations use the CB_COMPOUND procedure as a wrapper. In the processing of the CB_COMPOUND procedure, the client may find that it does not have the available resources to execute any or all of the operations within the CB_COMPOUND sequence. In this case, the error NFS4ERR_RESOURCE will be returned for the particular operation within the CB_COMPOUND procedure where the resource exhaustion occurred. This assumes that all previous operations within the CB_COMPOUND sequence have been evaluated successfully. Contained within the CB_COMPOUND results is a 'status' field. This status must be equivalent to the status of the last operation that was executed within the CB_COMPOUND procedure. Therefore, if an operation incurred an error then the 'status' value will be the same error value as is being returned for the operation that failed. - For the definition of the "tag" field, see Section 14.2 "Procedure 1: - COMPOUND - Compound Operations". + For the definition of the "tag" field, see Section 15.2. The value of callback_ident is supplied by the client during SETCLIENTID. The server must use the client supplied callback_ident during the CB_COMPOUND to allow the client to properly identify the server. Illegal operation codes are handled in the same way as they are handled for the COMPOUND procedure. -15.2.5. IMPLEMENTATION +16.2.5. IMPLEMENTATION The CB_COMPOUND procedure is used to combine individual operations into a single RPC request. The client interprets each of the operations in turn. If an operation is executed by the client and the status of that operation is NFS4_OK, then the next operation in the CB_COMPOUND procedure is executed. The client continues this process until there are no more operations to be executed or one of the operations has a status value other than NFS4_OK. -15.2.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_OP_ILLEGAL - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - -15.2.7. Operation 3: CB_GETATTR - Get Attributes +16.2.6. Operation 3: CB_GETATTR - Get Attributes -15.2.7.1. SYNOPSIS +16.2.6.1. SYNOPSIS fh, attr_request -> attrmask, attr_vals -15.2.7.2. ARGUMENT +16.2.6.2. ARGUMENT struct CB_GETATTR4args { nfs_fh4 fh; bitmap4 attr_request; }; -15.2.7.3. RESULT +16.2.6.3. RESULT struct CB_GETATTR4resok { fattr4 obj_attributes; }; union CB_GETATTR4res switch (nfsstat4 status) { case NFS4_OK: CB_GETATTR4resok resok4; default: void; }; -15.2.7.4. DESCRIPTION +16.2.6.4. DESCRIPTION The CB_GETATTR operation is used by the server to obtain the current modified state of a file that has been write delegated. The attributes size and change are the only ones guaranteed to be - serviced by the client. See Section 9.4.3 "Handling of CB_GETATTR" - for a full description of how the client and server are to interact - with the use of CB_GETATTR. + serviced by the client. See Section 10.4.3 for a full description of + how the client and server are to interact with the use of CB_GETATTR. If the filehandle specified is not one for which the client holds a write open delegation, an NFS4ERR_BADHANDLE error is returned. -15.2.7.5. IMPLEMENTATION +16.2.6.5. IMPLEMENTATION The client returns attrmask bits and the associated attribute values only for the change attribute, and attributes that it may change (time_modify, and size). -15.2.7.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_BADXDR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - -15.2.8. Operation 4: CB_RECALL - Recall an Open Delegation +16.2.7. Operation 4: CB_RECALL - Recall an Open Delegation -15.2.8.1. SYNOPSIS +16.2.7.1. SYNOPSIS stateid, truncate, fh -> () -15.2.8.2. ARGUMENT +16.2.7.2. ARGUMENT struct CB_RECALL4args { stateid4 stateid; bool truncate; nfs_fh4 fh; }; -15.2.8.3. RESULT +16.2.7.3. RESULT struct CB_RECALL4res { nfsstat4 status; }; -15.2.8.4. DESCRIPTION +16.2.7.4. DESCRIPTION The CB_RECALL operation is used to begin the process of recalling an open delegation and returning it to the server. The truncate flag is used to optimize recall for a file which is about to be truncated to zero. When it is set, the client is freed of obligation to propagate modified data for the file to the server, since this data is irrelevant. If the handle specified is not one for which the client holds an open delegation, an NFS4ERR_BADHANDLE error is returned. If the stateid specified is not one corresponding to an open delegation for the file specified by the filehandle, an NFS4ERR_BAD_STATEID is returned. -15.2.8.5. IMPLEMENTATION +16.2.7.5. IMPLEMENTATION The client should reply to the callback immediately. Replying does not complete the recall except when an error was returned. The recall is not complete until the delegation is returned using a DELEGRETURN. -15.2.8.6. ERRORS - - NFS4ERR_BADHANDLE - NFS4ERR_BAD_STATEID - NFS4ERR_BADXDR - NFS4ERR_RESOURCE - NFS4ERR_SERVERFAULT - -15.2.9. Operation 10044: CB_ILLEGAL - Illegal Callback Operation +16.2.8. Operation 10044: CB_ILLEGAL - Illegal Callback Operation -15.2.9.1. SYNOPSIS +16.2.8.1. SYNOPSIS -> () -15.2.9.2. ARGUMENT +16.2.8.2. ARGUMENT void; -15.2.9.3. RESULT +16.2.8.3. RESULT /* * CB_ILLEGAL: Response for illegal operation numbers */ struct CB_ILLEGAL4res { nfsstat4 status; }; -15.2.9.4. DESCRIPTION +16.2.8.4. DESCRIPTION This operation is a placeholder for encoding a result to handle the case of the client sending an operation code within COMPOUND that is - not supported. See Section 14.2.4 COMPOUND procedure description for - more details. + not supported. See Section 15.2.4 for more details. The status field of CB_ILLEGAL4res MUST be set to NFS4ERR_OP_ILLEGAL. -15.2.9.5. IMPLEMENTATION +16.2.8.5. IMPLEMENTATION A server will probably not send an operation with code OP_CB_ILLEGAL but if it does, the response will be CB_ILLEGAL4res just as it would be with any other invalid operation code. Note that if the client gets an illegal operation code that is not OP_ILLEGAL, and if the client checks for legal operation codes during the XDR decode phase, then the CB_ILLEGAL4res would not be returned. -15.2.9.6. ERRORS - - NFS4ERR_OP_ILLEGAL - -16. Security Considerations +17. Security Considerations NFS has historically used a model where, from an authentication perspective, the client was the entire machine, or at least the source IP address of the machine. The NFS server relied on the NFS client to make the proper authentication of the end-user. The NFS server in turn shared its files only to specific clients, as identified by the client's source IP address. Given this model, the AUTH_SYS RPC security flavor simply identified the end-user using the client to the NFS server. When processing NFS responses, the client ensured that the responses came from the same IP address and port number that the request was sent to. While such a model is easy to implement and simple to deploy and use, it is certainly not a safe model. Thus, NFSv4 mandates that implementations support a security model that uses end to end authentication, where an end-user on a client mutually authenticates (via cryptographic schemes that do not expose passwords or keys in the clear on the network) to a principal on an NFS server. Consideration should also be given to the integrity and privacy of NFS requests and responses. The issues of end to end mutual authentication, integrity, and privacy are - discussed as part of the section on "RPC and Security Flavor". + discussed as part of Section 3. Note that while NFSv4 mandates an end to end mutual authentication model, the "classic" model of machine authentication via IP address checking and AUTH_SYS identification can still be supported with the caveat that the AUTH_SYS flavor is neither MANDATORY nor RECOMMENDED by this specification, and so interoperability via AUTH_SYS is not assured. For reasons of reduced administration overhead, better performance and/or reduction of CPU utilization, users of NFS version 4 @@ -10856,52 +13489,51 @@ is any GETATTR for the fs_locations attribute. The attack has two steps. First the attacker modifies the unprotected results of some operation to return NFS4ERR_MOVED. Second, when the client follows up with a GETATTR for the fs_locations attribute, the attacker modifies the results to cause the client migrate its traffic to a server controlled by the attacker. Because the operations SETCLIENTID/SETCLIENTID_CONFIRM are responsible for the release of client state, it is imperative that the principal used for these operations is checked against and match - the previous use of these operations. See Section 8.1.1 "Client ID" - for further discussion. + the previous use of these operations. See Section 9.1.1 for further + discussion. -17. IANA Considerations +18. IANA Considerations -17.1. Named Attribute Definition +18.1. Named Attribute Definition The NFS version 4 protocol provides for the association of named attributes to files. The name space identifiers for these attributes are defined as string names. The protocol does not define the specific assignment of the name space for these file attributes. Even though the name space is not specifically controlled to prevent collisions, an IANA registry has been created for the registration of NFS version 4 named attributes. Registration will be achieved through the publication of an Informational RFC and will require not only the name of the attribute but the syntax and semantics of the named attribute contents; the intent is to promote interoperability where common interests exist. While application developers are allowed to define and use attributes as needed, they are encouraged to register the attributes with IANA. -17.2. ONC RPC Network Identifiers (netids) +18.2. ONC RPC Network Identifiers (netids) - The section "Structured Data Types" discussed the r_netid field and - the corresponding r_addr field of a clientaddr4 structure. The NFS - version 4 protocol depends on the syntax and semantics of these - fields to effectively communicate callback information between client - and server. Therefore, an IANA registry has been created to include - the values defined in this document and to allow for future expansion - based on transport usage/availability. Additions to this ONC RPC - Network Identifier registry must be done with the publication of an - RFC. + Section 2.2 discussed the r_netid field and the corresponding r_addr + field of a clientaddr4 structure. The NFS version 4 protocol depends + on the syntax and semantics of these fields to effectively + communicate callback information between client and server. + Therefore, an IANA registry has been created to include the values + defined in this document and to allow for future expansion based on + transport usage/availability. Additions to this ONC RPC Network + Identifier registry must be done with the publication of an RFC. The initial values for this registry are as follows (some of this text is replicated from section 2.2 for clarity): The Network Identifier (or r_netid for short) is used to specify a transport protocol and associated universal address (or r_addr for short). The syntax of the Network Identifier is a US-ASCII string. The initial definitions for r_netid are: "tcp" TCP over IP version 4 @@ -10931,38 +13563,39 @@ 527), then complete universal address is "10.1.3.7.2.15". For the "tcp6" and "udp6" Network Identifiers the Universal Address or r_addr (for IPv6) is a US-ASCII string and is of the form: x1:x2:x3:x4:x5:x6:x7:x8.p1.p2 The suffix "p1.p2" is the service port, and is computed the same way as with universal addresses for "tcp" and "udp". The prefix, "x1:x2: x3:x4:x5:x6:x7:x8", is the standard textual form for representing an - IPv6 address as defined in Section 2.2 of [17]. Additionally, the - two alternative forms specified in Section 2.2 of [17] are also + IPv6 address as defined in Section 2.2 of [18]. Additionally, the + two alternative forms specified in Section 2.2 of [18] are also acceptable. As mentioned, the registration of new Network Identifiers will require the publication of an Information RFC with similar detail as listed above for the Network Identifier itself and corresponding Universal Address. -18. References -18.1. Normative References +19. References + +19.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. - [2] Haynes, T., "NFSv4 Version 0 XDR Description", - draft-ietf-nfsv4-rfc3530bis-dot-x-01 (work in progress), - Mar 2010. + [2] Haynes, T. and D. Noveck, "NFSv4 Version 0 XDR Description", + draft-ietf-nfsv4-rfc3530bis-dot-x-02 (work in progress), + Jul 2010. [3] Srinivasan, R., "RPC: Remote Procedure Call Protocol Specification Version 2", RFC 1831, August 1995. [4] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol Specification", RFC 2203, September 1997. [5] Eisler, M., "LIPKEY - A Low Infrastructure Public Key Mechanism Using SPKM", RFC 2847, June 2000. @@ -10973,113 +13606,135 @@ Technology - Universal Multiple-octet coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual Plane", ISO Standard 10646-1, May 1993. [8] Alvestrand, H., "IETF Policy on Character Sets and Languages", BCP 18, RFC 2277, January 1998. [9] Hoffman, P. and M. Blanchet, "Preparation of Internationalized Strings ("stringprep")", RFC 3454, December 2002. -18.2. Informative References + [10] Klensin, J., "Internationalized Domain Names in Applications + (IDNA): Protocol", draft-ietf-idnabis-protocol-18 (work in + progress), January 2010. - [10] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame, +19.2. Informative References + + [11] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame, C., Eisler, M., and D. Noveck, "Network File System (NFS) version 4 Protocol", RFC 3530, April 2003. - [11] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame, + [12] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame, C., Eisler, M., and D. Noveck, "Network File System (NFS) version 4 Protocol", RFC 3010, December 2000. - [12] Nowicki, B., "NFS: Network File System Protocol specification", + [13] Nowicki, B., "NFS: Network File System Protocol specification", RFC 1094, March 1989. - [13] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS Version 3 + [14] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS Version 3 Protocol Specification", RFC 1813, June 1995. - [14] Srinivasan, R., "XDR: External Data Representation Standard", + [15] Srinivasan, R., "XDR: External Data Representation Standard", RFC 1832, August 1995. - [15] Linn, J., "The Kerberos Version 5 GSS-API Mechanism", RFC 1964, + [16] Linn, J., "The Kerberos Version 5 GSS-API Mechanism", RFC 1964, June 1996. - [16] Srinivasan, R., "Binding Protocols for ONC RPC Version 2", + [17] Srinivasan, R., "Binding Protocols for ONC RPC Version 2", RFC 1833, August 1995. - [17] Hinden, R. and S. Deering, "IP Version 6 Addressing + [18] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 2373, July 1998. - [18] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On- + [19] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On- line Database", RFC 3232, January 2002. - [19] Floyd, S. and V. Jacobson, "The Synchronization of Periodic + [20] Floyd, S. and V. Jacobson, "The Synchronization of Periodic Routing Messages", IEEE/ACM Transactions on Networking 2(2), pp. 122-136, April 1994. - [20] Eisler, M., "NFS Version 2 and Version 3 Security Issues and + [21] Eisler, M., "NFS Version 2 and Version 3 Security Issues and the NFS Protocol's Use of RPCSEC_GSS and Kerberos V5", RFC 2623, June 1999. - [21] Adams, C., "The Simple Public-Key GSS-API Mechanism (SPKM)", + [22] Adams, C., "The Simple Public-Key GSS-API Mechanism (SPKM)", RFC 2025, October 1996. - [22] Callaghan, B., "WebNFS Client Specification", RFC 2054, + [23] Callaghan, B., "WebNFS Client Specification", RFC 2054, October 1996. - [23] Callaghan, B., "WebNFS Server Specification", RFC 2055, + [24] Callaghan, B., "WebNFS Server Specification", RFC 2055, October 1996. - [24] Shepler, S., "NFS Version 4 Design Considerations", RFC 2624, + [25] Shepler, S., "NFS Version 4 Design Considerations", RFC 2624, June 1999. - [25] Simonsen, K., "Character Mnemonics and Character Sets", + [26] Simonsen, K., "Character Mnemonics and Character Sets", RFC 1345, June 1992. - [26] The Open Group, "Protocols for Interworking: XNFS, Version 3W, + [27] Shepler, S., Eisler, M., and D. Noveck, "Network File System + (NFS) Version 4 Minor Version 1 Protocol", RFC 5661, + January 2010. + + [28] The Open Group, "Protocols for Interworking: XNFS, Version 3W, ISBN 1-85912-184-5", February 1998. - [27] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, + [29] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981. - [28] Juszczak, C., "Improving the Performance and Correctness of an + [30] Juszczak, C., "Improving the Performance and Correctness of an NFS Server", USENIX Conference Proceedings , June 1990. - [29] Callaghan, B., "NFS URL Scheme", RFC 2224, October 1997. + [31] Callaghan, B., "NFS URL Scheme", RFC 2224, October 1997. - [30] Chiu, A., Eisler, M., and B. Callaghan, "Security Negotiation + [32] Chiu, A., Eisler, M., and B. Callaghan, "Security Negotiation for WebNFS", RFC 2755, January 2000. - [31] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA + [33] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. - [32] Noveck, D. and R. Burnett, "Implementation Guide for Referrals + [34] Noveck, D. and R. Burnett, "Implementation Guide for Referrals in NFSv4", draft-ietf-nfsv4-referrals-00 (work in progress), July 2005. - [33] Shepler, S., Eisler, M., and D. Noveck, "Network File System - (NFS) Version 4 Minor Version 1 Protocol", RFC 5661, - January 2010. - Appendix A. Acknowledgments -Appendix B. RFC Editor Notes - Rob Thurlow clarified how a client should contact a new server if a migration has occured. + David Black, Nico Williams, Mike Eisler and Trond Myklebust read many + drafts of Section 12 and contributed numerous useful suggestions, + without which the necessary revision of that section for this + document would not have been possible. + + Peter Staubach read almost all of the drafts of Section 12 leading to + the published result and his numerous comments were always useful and + contributed substantially to improving the quality of the final + result. + +Appendix B. RFC Editor Notes + [RFC Editor: please remove this section prior to publishing this document as an RFC] [RFC Editor: prior to publishing this document as an RFC, please replace all occurrences of RFCTBD10 with RFCxxxx where xxxx is the RFC number of this document] -Author's Address +Authors' Addresses Thomas Haynes Oracle 9110 E 66th St Tulsa, OK 74133 USA - Phone: +1-918-307-1415 + Phone: +1 918 307 1415 Email: tom.haynes@oracle.com + David Noveck + EMC + 32 Coslin Drive + Southborough, MA 01772 + US + + Phone: +1 508 305 8404 + Email: novecd@emc.com