--- 1/draft-ietf-nfsv4-rfc3010bis-02.txt 2006-02-05 00:48:45.000000000 +0100 +++ 2/draft-ietf-nfsv4-rfc3010bis-03.txt 2006-02-05 00:48:46.000000000 +0100 @@ -1,26 +1,26 @@ NFS version 4 Working Group S. Shepler INTERNET-DRAFT Sun Microsystems, Inc. -Document: draft-ietf-nfsv4-rfc3010bis-02.txt C. Beame - Hummingbird Ltd. +Obsoletes: 3010 C. Beame +Document: draft-ietf-nfsv4-rfc3010bis-03.txt Hummingbird Ltd. B. Callaghan Sun Microsystems, Inc. M. Eisler Network Appliance, Inc. D. Noveck Network Appliance, Inc. D. Robinson Sun Microsystems, Inc. R. Thurlow Sun Microsystems, Inc. - August 2002 + September 2002 NFS version 4 Protocol Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -36,41 +36,41 @@ 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. Abstract NFS version 4 is a distributed filesystem protocol which owes heritage to NFS protocol versions 2 [RFC1094] and 3 [RFC1813]. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. Copyright Copyright (C) The Internet Society (2000-2002). All Rights Reserved. Key Words 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 [RFC2119]. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 7 1.1. Inconsistencies of this Document with Section 18 . . . . . 7 1.2. Overview of NFS version 4 Features . . . . . . . . . . . . 8 1.2.1. RPC and Security . . . . . . . . . . . . . . . . . . . . 8 1.2.2. Procedure and Operation Structure . . . . . . . . . . . 8 1.2.3. Filesystem Model . . . . . . . . . . . . . . . . . . . . 9 1.2.3.1. Filehandle Types . . . . . . . . . . . . . . . . . . . 9 @@ -85,206 +85,208 @@ 2.2. Structured Data Types . . . . . . . . . . . . . . . . . 15 3. RPC and Security Flavor . . . . . . . . . . . . . . . . . 21 3.1. Ports and Transports . . . . . . . . . . . . . . . . . . 21 3.1.1. Client Retransmission Behavior . . . . . . . . . . . . 21 3.2. Security Flavors . . . . . . . . . . . . . . . . . . . . 22 3.2.1. Security mechanisms for NFS version 4 . . . . . . . . 22 3.2.1.1. Kerberos V5 as a security triple . . . . . . . . . . 22 3.2.1.2. LIPKEY as a security triple . . . . . . . . . . . . 23 3.2.1.3. SPKM-3 as a security triple . . . . . . . . . . . . 24 3.3. Security Negotiation . . . . . . . . . . . . . . . . . . 24 - 3.3.1. SECINFO . . . . . . . . . . . . . . . . . . . . . . . 25 + 3.3.1. SECINFO . . . . . . . . . . . . . . . . . . . . . . . 24 3.3.2. Security Error . . . . . . . . . . . . . . . . . . . . 25 3.4. Callback RPC Authentication . . . . . . . . . . . . . . 25 - 4. Filehandles . . . . . . . . . . . . . . . . . . . . . . . 28 - 4.1. Obtaining the First Filehandle . . . . . . . . . . . . . 28 - 4.1.1. Root Filehandle . . . . . . . . . . . . . . . . . . . 28 - 4.1.2. Public Filehandle . . . . . . . . . . . . . . . . . . 28 - 4.2. Filehandle Types . . . . . . . . . . . . . . . . . . . . 29 - 4.2.1. General Properties of a Filehandle . . . . . . . . . . 29 - 4.2.2. Persistent Filehandle . . . . . . . . . . . . . . . . 30 - 4.2.3. Volatile Filehandle . . . . . . . . . . . . . . . . . 30 - 4.2.4. One Method of Constructing a Volatile Filehandle . . . 31 - 4.3. Client Recovery from Filehandle Expiration . . . . . . . 32 - 5. File Attributes . . . . . . . . . . . . . . . . . . . . . 34 - 5.1. Mandatory Attributes . . . . . . . . . . . . . . . . . . 35 - 5.2. Recommended Attributes . . . . . . . . . . . . . . . . . 35 - 5.3. Named Attributes . . . . . . . . . . . . . . . . . . . . 35 - 5.4. Classification of Attributes . . . . . . . . . . . . . . 36 - 5.5. Mandatory Attributes - Definitions . . . . . . . . . . . 38 - 5.6. Recommended Attributes - Definitions . . . . . . . . . . 40 - 5.7. Time Access . . . . . . . . . . . . . . . . . . . . . . 45 - 5.8. Interpreting owner and owner_group . . . . . . . . . . . 45 - 5.9. Character Case Attributes . . . . . . . . . . . . . . . 47 - 5.10. Quota Attributes . . . . . . . . . . . . . . . . . . . 47 - 5.11. Access Control Lists . . . . . . . . . . . . . . . . . 48 + 4. Filehandles . . . . . . . . . . . . . . . . . . . . . . . 27 + 4.1. Obtaining the First Filehandle . . . . . . . . . . . . . 27 + 4.1.1. Root Filehandle . . . . . . . . . . . . . . . . . . . 27 + 4.1.2. Public Filehandle . . . . . . . . . . . . . . . . . . 27 + 4.2. Filehandle Types . . . . . . . . . . . . . . . . . . . . 28 + 4.2.1. General Properties of a Filehandle . . . . . . . . . . 28 + 4.2.2. Persistent Filehandle . . . . . . . . . . . . . . . . 29 + 4.2.3. Volatile Filehandle . . . . . . . . . . . . . . . . . 29 + 4.2.4. One Method of Constructing a Volatile Filehandle . . . 30 + 4.3. Client Recovery from Filehandle Expiration . . . . . . . 31 + 5. File Attributes . . . . . . . . . . . . . . . . . . . . . 33 + 5.1. Mandatory Attributes . . . . . . . . . . . . . . . . . . 34 + 5.2. Recommended Attributes . . . . . . . . . . . . . . . . . 34 + 5.3. Named Attributes . . . . . . . . . . . . . . . . . . . . 34 + 5.4. Classification of Attributes . . . . . . . . . . . . . . 35 + 5.5. Mandatory Attributes - Definitions . . . . . . . . . . . 37 + 5.6. Recommended Attributes - Definitions . . . . . . . . . . 39 + 5.7. Time Access . . . . . . . . . . . . . . . . . . . . . . 44 + 5.8. Interpreting owner and owner_group . . . . . . . . . . . 44 + 5.9. Character Case Attributes . . . . . . . . . . . . . . . 46 + 5.10. Quota Attributes . . . . . . . . . . . . . . . . . . . 46 + 5.11. Access Control Lists . . . . . . . . . . . . . . . . . 47 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - 5.11.1. ACE type . . . . . . . . . . . . . . . . . . . . . . 49 - 5.11.2. ACE Access Mask . . . . . . . . . . . . . . . . . . . 50 - 5.11.3. ACE flag . . . . . . . . . . . . . . . . . . . . . . 52 - 5.11.4. ACE who . . . . . . . . . . . . . . . . . . . . . . . 53 - 5.11.5. Mode Attribute . . . . . . . . . . . . . . . . . . . 54 - 5.11.6. Mode and ACL Attribute . . . . . . . . . . . . . . . 55 - 5.11.7. mounted_on_fileid . . . . . . . . . . . . . . . . . . 55 - 6. Filesystem Migration and Replication . . . . . . . . . . . 57 - 6.1. Replication . . . . . . . . . . . . . . . . . . . . . . 57 - 6.2. Migration . . . . . . . . . . . . . . . . . . . . . . . 57 - 6.3. Interpretation of the fs_locations Attribute . . . . . . 58 - 6.4. Filehandle Recovery for Migration or Replication . . . . 59 - 7. NFS Server Name Space . . . . . . . . . . . . . . . . . . 60 - 7.1. Server Exports . . . . . . . . . . . . . . . . . . . . . 60 - 7.2. Browsing Exports . . . . . . . . . . . . . . . . . . . . 60 - 7.3. Server Pseudo Filesystem . . . . . . . . . . . . . . . . 60 - 7.4. Multiple Roots . . . . . . . . . . . . . . . . . . . . . 61 - 7.5. Filehandle Volatility . . . . . . . . . . . . . . . . . 61 - 7.6. Exported Root . . . . . . . . . . . . . . . . . . . . . 61 - 7.7. Mount Point Crossing . . . . . . . . . . . . . . . . . . 62 - 7.8. Security Policy and Name Space Presentation . . . . . . 62 - 8. File Locking and Share Reservations . . . . . . . . . . . 64 - 8.1. Locking . . . . . . . . . . . . . . . . . . . . . . . . 64 - 8.1.1. Client ID . . . . . . . . . . . . . . . . . . . . . . 64 - 8.1.2. Server Release of Clientid . . . . . . . . . . . . . . 67 - 8.1.3. lock_owner and stateid Definition . . . . . . . . . . 68 - 8.1.4. Use of the stateid and Locking . . . . . . . . . . . . 69 - 8.1.5. Sequencing of Lock Requests . . . . . . . . . . . . . 71 - 8.1.6. Recovery from Replayed Requests . . . . . . . . . . . 72 + 5.11.1. ACE type . . . . . . . . . . . . . . . . . . . . . . 48 + 5.11.2. ACE Access Mask . . . . . . . . . . . . . . . . . . . 49 + 5.11.3. ACE flag . . . . . . . . . . . . . . . . . . . . . . 51 + 5.11.4. ACE who . . . . . . . . . . . . . . . . . . . . . . . 52 + 5.11.5. Mode Attribute . . . . . . . . . . . . . . . . . . . 53 + 5.11.6. Mode and ACL Attribute . . . . . . . . . . . . . . . 54 + 5.11.7. mounted_on_fileid . . . . . . . . . . . . . . . . . . 54 + 6. Filesystem Migration and Replication . . . . . . . . . . . 56 + 6.1. Replication . . . . . . . . . . . . . . . . . . . . . . 56 + 6.2. Migration . . . . . . . . . . . . . . . . . . . . . . . 56 + 6.3. Interpretation of the fs_locations Attribute . . . . . . 57 + 6.4. Filehandle Recovery for Migration or Replication . . . . 58 + 7. NFS Server Name Space . . . . . . . . . . . . . . . . . . 59 + 7.1. Server Exports . . . . . . . . . . . . . . . . . . . . . 59 + 7.2. Browsing Exports . . . . . . . . . . . . . . . . . . . . 59 + 7.3. Server Pseudo Filesystem . . . . . . . . . . . . . . . . 59 + 7.4. Multiple Roots . . . . . . . . . . . . . . . . . . . . . 60 + 7.5. Filehandle Volatility . . . . . . . . . . . . . . . . . 60 + 7.6. Exported Root . . . . . . . . . . . . . . . . . . . . . 60 + 7.7. Mount Point Crossing . . . . . . . . . . . . . . . . . . 61 + 7.8. Security Policy and Name Space Presentation . . . . . . 61 + 8. File Locking and Share Reservations . . . . . . . . . . . 63 + 8.1. Locking . . . . . . . . . . . . . . . . . . . . . . . . 63 + 8.1.1. Client ID . . . . . . . . . . . . . . . . . . . . . . 63 + 8.1.2. Server Release of Clientid . . . . . . . . . . . . . . 66 + 8.1.3. lock_owner and stateid Definition . . . . . . . . . . 67 + 8.1.4. Use of the stateid and Locking . . . . . . . . . . . . 68 + 8.1.5. Sequencing of Lock Requests . . . . . . . . . . . . . 70 + 8.1.6. Recovery from Replayed Requests . . . . . . . . . . . 71 8.1.7. Releasing lock_owner State . . . . . . . . . . . . . . 72 - 8.1.8. Use of Open Confirmation . . . . . . . . . . . . . . . 73 - 8.2. Lock Ranges . . . . . . . . . . . . . . . . . . . . . . 74 - 8.3. Upgrading and Downgrading Locks . . . . . . . . . . . . 74 - 8.4. Blocking Locks . . . . . . . . . . . . . . . . . . . . . 75 - 8.5. Lease Renewal . . . . . . . . . . . . . . . . . . . . . 75 - 8.6. Crash Recovery . . . . . . . . . . . . . . . . . . . . . 76 + 8.1.8. Use of Open Confirmation . . . . . . . . . . . . . . . 72 + 8.2. Lock Ranges . . . . . . . . . . . . . . . . . . . . . . 73 + 8.3. Upgrading and Downgrading Locks . . . . . . . . . . . . 73 + 8.4. Blocking Locks . . . . . . . . . . . . . . . . . . . . . 74 + 8.5. Lease Renewal . . . . . . . . . . . . . . . . . . . . . 74 + 8.6. Crash Recovery . . . . . . . . . . . . . . . . . . . . . 75 8.6.1. Client Failure and Recovery . . . . . . . . . . . . . 76 - 8.6.2. Server Failure and Recovery . . . . . . . . . . . . . 77 - 8.6.3. Network Partitions and Recovery . . . . . . . . . . . 79 - 8.7. Recovery from a Lock Request Timeout or Abort . . . . . 80 - 8.8. Server Revocation of Locks . . . . . . . . . . . . . . . 80 - 8.9. Share Reservations . . . . . . . . . . . . . . . . . . . 81 - 8.10. OPEN/CLOSE Operations . . . . . . . . . . . . . . . . . 82 - 8.10.1. Close and Retention of State Information . . . . . . 83 - 8.11. Open Upgrade and Downgrade . . . . . . . . . . . . . . 83 - 8.12. Short and Long Leases . . . . . . . . . . . . . . . . . 84 + 8.6.2. Server Failure and Recovery . . . . . . . . . . . . . 76 + 8.6.3. Network Partitions and Recovery . . . . . . . . . . . 78 + 8.7. Recovery from a Lock Request Timeout or Abort . . . . . 81 + 8.8. Server Revocation of Locks . . . . . . . . . . . . . . . 82 + 8.9. Share Reservations . . . . . . . . . . . . . . . . . . . 83 + 8.10. OPEN/CLOSE Operations . . . . . . . . . . . . . . . . . 83 + 8.10.1. Close and Retention of State Information . . . . . . 84 + 8.11. Open Upgrade and Downgrade . . . . . . . . . . . . . . 85 + 8.12. Short and Long Leases . . . . . . . . . . . . . . . . . 85 8.13. Clocks, Propagation Delay, and Calculating Lease - Expiration . . . . . . . . . . . . . . . . . . . . . . 84 - 8.14. Migration, Replication and State . . . . . . . . . . . 85 - 8.14.1. Migration and State . . . . . . . . . . . . . . . . . 85 - 8.14.2. Replication and State . . . . . . . . . . . . . . . . 86 - 8.14.3. Notification of Migrated Lease . . . . . . . . . . . 86 + Expiration . . . . . . . . . . . . . . . . . . . . . . 86 + 8.14. Migration, Replication and State . . . . . . . . . . . 86 + 8.14.1. Migration and State . . . . . . . . . . . . . . . . . 87 + 8.14.2. Replication and State . . . . . . . . . . . . . . . . 87 + 8.14.3. Notification of Migrated Lease . . . . . . . . . . . 88 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - 8.14.4. Migration and the Lease_time Attribute . . . . . . . 87 - 9. Client-Side Caching . . . . . . . . . . . . . . . . . . . 88 - 9.1. Performance Challenges for Client-Side Caching . . . . . 88 - 9.2. Delegation and Callbacks . . . . . . . . . . . . . . . . 89 - 9.2.1. Delegation Recovery . . . . . . . . . . . . . . . . . 90 - 9.3. Data Caching . . . . . . . . . . . . . . . . . . . . . . 92 - 9.3.1. Data Caching and OPENs . . . . . . . . . . . . . . . . 92 - 9.3.2. Data Caching and File Locking . . . . . . . . . . . . 93 - 9.3.3. Data Caching and Mandatory File Locking . . . . . . . 95 - 9.3.4. Data Caching and File Identity . . . . . . . . . . . . 95 - 9.4. Open Delegation . . . . . . . . . . . . . . . . . . . . 96 - 9.4.1. Open Delegation and Data Caching . . . . . . . . . . . 99 - 9.4.2. Open Delegation and File Locks . . . . . . . . . . . . 100 - 9.4.3. Handling of CB_GETATTR . . . . . . . . . . . . . . . . 100 - 9.4.4. Recall of Open Delegation . . . . . . . . . . . . . . 102 - 9.4.5. Delegation Revocation . . . . . . . . . . . . . . . . 104 - 9.5. Data Caching and Revocation . . . . . . . . . . . . . . 104 - 9.5.1. Revocation Recovery for Write Open Delegation . . . . 104 - 9.6. Attribute Caching . . . . . . . . . . . . . . . . . . . 105 - 9.7. Name Caching . . . . . . . . . . . . . . . . . . . . . . 107 - 9.8. Directory Caching . . . . . . . . . . . . . . . . . . . 108 - 10. Minor Versioning . . . . . . . . . . . . . . . . . . . . 110 - 11. Internationalization . . . . . . . . . . . . . . . . . . 113 - 11.1. Universal Versus Local Character Sets . . . . . . . . . 113 - 11.2. Overview of Universal Character Set Standards . . . . . 114 - 11.3. Difficulties with UCS-4, UCS-2, Unicode . . . . . . . . 115 - 11.4. UTF-8 and its solutions . . . . . . . . . . . . . . . . 115 - 11.5. Normalization . . . . . . . . . . . . . . . . . . . . . 116 - 11.6. UTF-8 Related Errors . . . . . . . . . . . . . . . . . 116 - 12. Error Definitions . . . . . . . . . . . . . . . . . . . . 118 - 13. NFS version 4 Requests . . . . . . . . . . . . . . . . . 124 - 13.1. Compound Procedure . . . . . . . . . . . . . . . . . . 124 - 13.2. Evaluation of a Compound Request . . . . . . . . . . . 125 - 13.3. Synchronous Modifying Operations . . . . . . . . . . . 125 - 13.4. Operation Values . . . . . . . . . . . . . . . . . . . 126 - 14. NFS version 4 Procedures . . . . . . . . . . . . . . . . 127 - 14.1. Procedure 0: NULL - No Operation . . . . . . . . . . . 127 - 14.2. Procedure 1: COMPOUND - Compound Operations . . . . . . 128 - 14.2.1. Operation 3: ACCESS - Check Access Rights . . . . . . 131 - 14.2.2. Operation 4: CLOSE - Close File . . . . . . . . . . . 134 - 14.2.3. Operation 5: COMMIT - Commit Cached Data . . . . . . 136 - 14.2.4. Operation 6: CREATE - Create a Non-Regular File Object 139 + 8.14.4. Migration and the Lease_time Attribute . . . . . . . 88 + 9. Client-Side Caching . . . . . . . . . . . . . . . . . . . 90 + 9.1. Performance Challenges for Client-Side Caching . . . . . 90 + 9.2. Delegation and Callbacks . . . . . . . . . . . . . . . . 91 + 9.2.1. Delegation Recovery . . . . . . . . . . . . . . . . . 92 + 9.3. Data Caching . . . . . . . . . . . . . . . . . . . . . . 94 + 9.3.1. Data Caching and OPENs . . . . . . . . . . . . . . . . 94 + 9.3.2. Data Caching and File Locking . . . . . . . . . . . . 95 + 9.3.3. Data Caching and Mandatory File Locking . . . . . . . 97 + 9.3.4. Data Caching and File Identity . . . . . . . . . . . . 97 + 9.4. Open Delegation . . . . . . . . . . . . . . . . . . . . 98 + 9.4.1. Open Delegation and Data Caching . . . . . . . . . . . 101 + 9.4.2. Open Delegation and File Locks . . . . . . . . . . . . 102 + 9.4.3. Handling of CB_GETATTR . . . . . . . . . . . . . . . . 102 + 9.4.4. Recall of Open Delegation . . . . . . . . . . . . . . 105 + 9.4.5. Clients that Fail to Honor Delegation Recalls . . . . 107 + 9.4.6. Delegation Revocation . . . . . . . . . . . . . . . . 107 + 9.5. Data Caching and Revocation . . . . . . . . . . . . . . 108 + 9.5.1. Revocation Recovery for Write Open Delegation . . . . 108 + 9.6. Attribute Caching . . . . . . . . . . . . . . . . . . . 109 + 9.7. Data and Metadata Caching and Memory Mapped Files . . . 111 + 9.8. Name Caching . . . . . . . . . . . . . . . . . . . . . . 113 + 9.9. Directory Caching . . . . . . . . . . . . . . . . . . . 114 + 10. Minor Versioning . . . . . . . . . . . . . . . . . . . . 116 + 11. Internationalization . . . . . . . . . . . . . . . . . . 119 + 11.1. Universal Versus Local Character Sets . . . . . . . . . 119 + 11.2. Overview of Universal Character Set Standards . . . . . 120 + 11.3. Difficulties with UCS-4, UCS-2, Unicode . . . . . . . . 121 + 11.4. UTF-8 and its solutions . . . . . . . . . . . . . . . . 121 + 11.5. Normalization . . . . . . . . . . . . . . . . . . . . . 122 + 11.6. UTF-8 Related Errors . . . . . . . . . . . . . . . . . 122 + 12. Error Definitions . . . . . . . . . . . . . . . . . . . . 124 + 13. NFS version 4 Requests . . . . . . . . . . . . . . . . . 130 + 13.1. Compound Procedure . . . . . . . . . . . . . . . . . . 130 + 13.2. Evaluation of a Compound Request . . . . . . . . . . . 131 + 13.3. Synchronous Modifying Operations . . . . . . . . . . . 131 + 13.4. Operation Values . . . . . . . . . . . . . . . . . . . 132 + 14. NFS version 4 Procedures . . . . . . . . . . . . . . . . 133 + 14.1. Procedure 0: NULL - No Operation . . . . . . . . . . . 133 + 14.2. Procedure 1: COMPOUND - Compound Operations . . . . . . 134 + 14.2.1. Operation 3: ACCESS - Check Access Rights . . . . . . 137 + 14.2.2. Operation 4: CLOSE - Close File . . . . . . . . . . . 140 + 14.2.3. Operation 5: COMMIT - Commit Cached Data . . . . . . 142 + 14.2.4. Operation 6: CREATE - Create a Non-Regular File Object 145 14.2.5. Operation 7: DELEGPURGE - Purge Delegations Awaiting - Recovery . . . . . . . . . . . . . . . . . . . . . . 142 - 14.2.6. Operation 8: DELEGRETURN - Return Delegation . . . . 143 - 14.2.7. Operation 9: GETATTR - Get Attributes . . . . . . . . 144 - 14.2.8. Operation 10: GETFH - Get Current Filehandle . . . . 146 - 14.2.9. Operation 11: LINK - Create Link to a File . . . . . 148 - 14.2.10. Operation 12: LOCK - Create Lock . . . . . . . . . . 150 - 14.2.11. Operation 13: LOCKT - Test For Lock . . . . . . . . 154 - 14.2.12. Operation 14: LOCKU - Unlock File . . . . . . . . . 156 - 14.2.13. Operation 15: LOOKUP - Lookup Filename . . . . . . . 158 + Recovery . . . . . . . . . . . . . . . . . . . . . . 148 + 14.2.6. Operation 8: DELEGRETURN - Return Delegation . . . . 150 + 14.2.7. Operation 9: GETATTR - Get Attributes . . . . . . . . 151 + 14.2.8. Operation 10: GETFH - Get Current Filehandle . . . . 153 + 14.2.9. Operation 11: LINK - Create Link to a File . . . . . 155 + 14.2.10. Operation 12: LOCK - Create Lock . . . . . . . . . . 157 + 14.2.11. Operation 13: LOCKT - Test For Lock . . . . . . . . 161 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - 14.2.14. Operation 16: LOOKUPP - Lookup Parent Directory . . 161 + 14.2.12. Operation 14: LOCKU - Unlock File . . . . . . . . . 163 + 14.2.13. Operation 15: LOOKUP - Lookup Filename . . . . . . . 165 + 14.2.14. Operation 16: LOOKUPP - Lookup Parent Directory . . 168 14.2.15. Operation 17: NVERIFY - Verify Difference in - Attributes . . . . . . . . . . . . . . . . . . . . . 162 - 14.2.16. Operation 18: OPEN - Open a Regular File . . . . . . 164 + Attributes . . . . . . . . . . . . . . . . . . . . . 169 + 14.2.16. Operation 18: OPEN - Open a Regular File . . . . . . 171 14.2.17. Operation 19: OPENATTR - Open Named Attribute - Directory . . . . . . . . . . . . . . . . . . . . . 174 - 14.2.18. Operation 20: OPEN_CONFIRM - Confirm Open . . . . . 176 - 14.2.19. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access179 - 14.2.20. Operation 22: PUTFH - Set Current Filehandle . . . . 181 - 14.2.21. Operation 23: PUTPUBFH - Set Public Filehandle . . . 182 - 14.2.22. Operation 24: PUTROOTFH - Set Root Filehandle . . . 184 - 14.2.23. Operation 25: READ - Read from File . . . . . . . . 185 - 14.2.24. Operation 26: READDIR - Read Directory . . . . . . . 188 - 14.2.25. Operation 27: READLINK - Read Symbolic Link . . . . 192 - 14.2.26. Operation 28: REMOVE - Remove Filesystem Object . . 194 - 14.2.27. Operation 29: RENAME - Rename Directory Entry . . . 197 - 14.2.28. Operation 30: RENEW - Renew a Lease . . . . . . . . 200 - 14.2.29. Operation 31: RESTOREFH - Restore Saved Filehandle . 201 - 14.2.30. Operation 32: SAVEFH - Save Current Filehandle . . . 203 - 14.2.31. Operation 33: SECINFO - Obtain Available Security . 204 - 14.2.32. Operation 34: SETATTR - Set Attributes . . . . . . . 208 - 14.2.33. Operation 35: SETCLIENTID - Negotiate Clientid . . . 211 - 14.2.34. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid 215 - 14.2.35. Operation 37: VERIFY - Verify Same Attributes . . . 219 - 14.2.36. Operation 38: WRITE - Write to File . . . . . . . . 221 + Directory . . . . . . . . . . . . . . . . . . . . . 181 + 14.2.18. Operation 20: OPEN_CONFIRM - Confirm Open . . . . . 183 + 14.2.19. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access186 + 14.2.20. Operation 22: PUTFH - Set Current Filehandle . . . . 188 + 14.2.21. Operation 23: PUTPUBFH - Set Public Filehandle . . . 189 + 14.2.22. Operation 24: PUTROOTFH - Set Root Filehandle . . . 191 + 14.2.23. Operation 25: READ - Read from File . . . . . . . . 192 + 14.2.24. Operation 26: READDIR - Read Directory . . . . . . . 195 + 14.2.25. Operation 27: READLINK - Read Symbolic Link . . . . 199 + 14.2.26. Operation 28: REMOVE - Remove Filesystem Object . . 201 + 14.2.27. Operation 29: RENAME - Rename Directory Entry . . . 204 + 14.2.28. Operation 30: RENEW - Renew a Lease . . . . . . . . 207 + 14.2.29. Operation 31: RESTOREFH - Restore Saved Filehandle . 209 + 14.2.30. Operation 32: SAVEFH - Save Current Filehandle . . . 211 + 14.2.31. Operation 33: SECINFO - Obtain Available Security . 212 + 14.2.32. Operation 34: SETATTR - Set Attributes . . . . . . . 216 + 14.2.33. Operation 35: SETCLIENTID - Negotiate Clientid . . . 219 + 14.2.34. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid 223 + 14.2.35. Operation 37: VERIFY - Verify Same Attributes . . . 227 + 14.2.36. Operation 38: WRITE - Write to File . . . . . . . . 229 14.2.37. Operation 39: RELEASE_LOCKOWNER - Release Lockowner - State . . . . . . . . . . . . . . . . . . . . . . . 226 - 14.2.38. Operation 10044: ILLEGAL - Illegal operation . . . . 228 - 15. NFS version 4 Callback Procedures . . . . . . . . . . . . 229 - 15.1. Procedure 0: CB_NULL - No Operation . . . . . . . . . . 229 - 15.2. Procedure 1: CB_COMPOUND - Compound Operations . . . . 230 - 15.2.1. Operation 3: CB_GETATTR - Get Attributes . . . . . . 232 - 15.2.2. Operation 4: CB_RECALL - Recall an Open Delegation . 234 + State . . . . . . . . . . . . . . . . . . . . . . . 234 + 14.2.38. Operation 10044: ILLEGAL - Illegal operation . . . . 236 + 15. NFS version 4 Callback Procedures . . . . . . . . . . . . 237 + 15.1. Procedure 0: CB_NULL - No Operation . . . . . . . . . . 237 + 15.2. Procedure 1: CB_COMPOUND - Compound Operations . . . . 238 + 15.2.1. Operation 3: CB_GETATTR - Get Attributes . . . . . . 240 + 15.2.2. Operation 4: CB_RECALL - Recall an Open Delegation . 242 15.2.3. Operation 10044: CB_ILLEGAL - Illegal Callback - Operation . . . . . . . . . . . . . . . . . . . . . . 236 - 16. Security Considerations . . . . . . . . . . . . . . . . . 237 - 17. IANA Considerations . . . . . . . . . . . . . . . . . . . 238 - 17.1. Named Attribute Definition . . . . . . . . . . . . . . 238 - 17.2. ONC RPC Network Identifiers (netids) . . . . . . . . . 238 - 18. RPC definition file . . . . . . . . . . . . . . . . . . . 239 - 19. Bibliography . . . . . . . . . . . . . . . . . . . . . . 271 - 20. Authors . . . . . . . . . . . . . . . . . . . . . . . . . 277 - 20.1. Editor's Address . . . . . . . . . . . . . . . . . . . 277 - 20.2. Authors' Addresses . . . . . . . . . . . . . . . . . . 277 - 20.3. Acknowledgements . . . . . . . . . . . . . . . . . . . 278 - 21. Full Copyright Statement . . . . . . . . . . . . . . . . 279 + Operation . . . . . . . . . . . . . . . . . . . . . . 244 + 16. Security Considerations . . . . . . . . . . . . . . . . . 245 + 17. IANA Considerations . . . . . . . . . . . . . . . . . . . 246 + 17.1. Named Attribute Definition . . . . . . . . . . . . . . 246 + 17.2. ONC RPC Network Identifiers (netids) . . . . . . . . . 246 + 18. RPC definition file . . . . . . . . . . . . . . . . . . . 247 + 19. Bibliography . . . . . . . . . . . . . . . . . . . . . . 279 + 20. Authors . . . . . . . . . . . . . . . . . . . . . . . . . 285 + 20.1. Editor's Address . . . . . . . . . . . . . . . . . . . 285 + 20.2. Authors' Addresses . . . . . . . . . . . . . . . . . . 285 + 20.3. Acknowledgements . . . . . . . . . . . . . . . . . . . 286 + 21. Full Copyright Statement . . . . . . . . . . . . . . . . 287 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 1. Introduction The NFS version 4 protocol is a further revision of the NFS protocol defined already by versions 2 [RFC1094] and 3 [RFC1813]. 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: @@ -316,21 +318,21 @@ 1.1. Inconsistencies of this Document with Section 18 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 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 1.2. 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 @@ -369,21 +371,21 @@ The COMPOUND procedure is defined in terms of operations and these operations correspond more closely to the traditional NFS procedures. With the use of the COMPOUND procedure, the client is able to build simple or complex requests. These COMPOUND requests allow for a reduction in the number of RPCs needed for logical filesystem operations. For example, without previous contact with a server a client will be able to read data from a file in one request by combining LOOKUP, OPEN, and READ operations in a single COMPOUND RPC. With previous versions of the NFS protocol, this type of single -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 request was not possible. The model used for COMPOUND is very simple. There is no logical OR or ANDing of operations. The operations combined within a COMPOUND request are evaluated in order by the server. Once an operation returns a failing result, the evaluation ends and the results of all evaluated operations are returned to the client. The NFS version 4 protocol continues to have the client refer to a @@ -402,39 +404,39 @@ the same as previous versions. The server filesystem is hierarchical with the regular files contained within being treated as opaque byte streams. In a slight departure, file and directory names are encoded with UTF-8 to deal with the basics of internationalization. The NFS version 4 protocol does not require a separate protocol to provide for the initial mapping between path name and filehandle. Instead of using the older MOUNT protocol for this mapping, the server provides a ROOT filehandle that represents the logical root or top of the filesystem tree provided by the server. The server - provides multiple filesystems by glueing them together with pseudo + provides multiple filesystems by gluing them together with pseudo filesystems. These pseudo filesystems provide for potential gaps in the path names between real filesystems. 1.2.3.1. Filehandle Types In previous versions of the NFS protocol, the filehandle provided by the server was guaranteed to be valid or persistent for the lifetime of the filesystem object to which it referred. For some server implementations, this persistence requirement has been difficult to meet. For the NFS version 4 protocol, this requirement has been relaxed by introducing another type of filehandle, volatile. With persistent and volatile filehandle types, the server implementation can match the abilities of the filesystem at the server along with the operating environment. The client will have knowledge of the type of filehandle being provided by the server and can be prepared to deal with the semantics of each. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 1.2.3.2. Attribute Types The NFS version 4 protocol introduces three classes of filesystem or file attributes. Like the additional filehandle type, the classification of file attributes has been done to ease server implementations along with extending the overall functionality of the NFS protocol. This attribute model is structured to be extensible such that new attributes can be introduced in minor revisions of the protocol without requiring significant rework. @@ -471,21 +473,21 @@ replicate server filesystems is enabled within the protocol. 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 1.2.4. 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. 1.2.5. File locking @@ -523,21 +525,21 @@ client. When the server grants a delegation for a file to a client, the client is guaranteed certain semantics with respect to the sharing of that file with other clients. At OPEN, the server may provide the client either a read or write delegation for the file. If the client is granted a read delegation, it is assured that no other client has the ability to write to the file for the duration of the delegation. If the client is granted a write delegation, the client is assured that no other client has read or write access to the file. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Delegations can be recalled by the server. If another client requests access to the file in such a way that the access conflicts with the granted delegation, the server is able to notify the initial client and recall the delegation. This requires that a callback path exist between the server and client. If this callback path does not exist, then delegations can not be granted. The essence of a delegation is that it allows the client to locally service operations such as OPEN, CLOSE, LOCK, LOCKU, READ, WRITE without immediate interaction with the server. @@ -576,21 +578,21 @@ alleviate the expense a server would have in maintaining state about variable length leases across server failures. Lock The term "lock" is used to refer to both record (byte- range) locks as well as share reservations unless specifically stated otherwise. Server The "Server" is the entity responsible for coordinating client access to a set of filesystems. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Stable Storage NFS version 4 servers must be able to recover without data loss from multiple power failures (including cascading power failures, that is, several power failures in quick succession), operating system failures, and hardware failure of components other than the storage medium itself (for example, disk, nonvolatile RAM). Some examples of stable storage that are allowable for an @@ -614,21 +616,21 @@ defines the open and locking state provided by the server for a specific open or lock owner for a specific file. 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 2. Protocol Data Types The syntax and semantics to describe the data types of the NFS version 4 protocol are defined in the XDR [RFC1832] and RPC [RFC1831] documents. The next sections build upon the XDR data types to define types and structures specific to this protocol. 2.1. Basic Data Types @@ -668,21 +670,21 @@ mode4 typedef uint32_t mode4; Mode attribute data type nfs_cookie4 typedef uint64_t nfs_cookie4; Opaque cookie value for READDIR nfs_fh4 typedef opaque nfs_fh4; Filehandle definition; NFS4_FHSIZE is defined as 128 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 nfs_ftype4 enum nfs_ftype4; Various defined file types nfsstat4 enum nfsstat4; Return value for operations offset4 typedef uint64_t offset4; Various offset designations (READ, WRITE, LOCK, COMMIT) @@ -701,40 +703,40 @@ seqid4 typedef uint32_t seqid4; Sequence identifier used for file locking utf8string typedef opaque utf8string<>; UTF-8 encoding for strings verifier4 typedef opaque verifier4[NFS4_VERIFIER_SIZE]; Verifier used for various operations (COMMIT, CREATE, OPEN, READDIR, SETCLIENTID, SETCLIENTID_CONFIRM, WRITE) - NFS4_VERIFIER_SIZE is defined as 8 + NFS4_VERIFIER_SIZE is defined as 8. 2.2. Structured Data Types 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 after the 0 hour January 1, 1970. Values less than zero for the seconds field denote dates before the 0 hour January 1, 1970. In both cases, the nseconds field is to be added to the seconds field for the final time representation. For example, if the time to be represented is one-half second -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 before 0 hour January 1, 1970, the seconds field would have a value of negative one (-1) and the nseconds fields would have a value of one-half second (500000000). Values greater than 999,999,999 for nseconds are considered invalid. This data type is used to pass time and date information. A server converts to and from its local representation of time when processing time values, preserving as much accuracy as possible. If the precision of timestamps stored for a filesystem @@ -771,21 +773,21 @@ This data type represents additional information for the device file types NF4CHR and NF4BLK. fsid4 struct fsid4 { uint64_t major; uint64_t minor; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 }; This type is the filesystem identifier that is used as a mandatory attribute. fs_location4 struct fs_location4 { utf8string server<>; @@ -822,21 +824,21 @@ +-----------+-----------+-----------+-- | count | 31 .. 0 | 63 .. 32 | +-----------+-----------+-----------+-- change_info4 struct change_info4 { bool atomic; changeid4 before; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 changeid4 after; }; This structure is used with the CREATE, LINK, REMOVE, RENAME operations to let the client know the value of the change attribute for the directory in which the target filesystem object resides. clientaddr4 @@ -872,25 +874,25 @@ For TCP over IPv4 the value of r_netid is the string "tcp". For UDP over IPv4 the value of r_netid is the string "udp". For TCP over IPv4 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 univeral addresses for TCP and UDP over IPv4. The + 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 [RFC1884]. Additionally, the two alternative forms specified in Section 2.2 of [RFC1884] 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". cb_client4 struct cb_client4 { @@ -925,21 +927,21 @@ lock_owner4 struct lock_owner4 { clientid4 clientid; opaque owner; }; This structure is used to identify the owner of file locking state. NFS4_OPAQUE_LIMIT is defined as 1024. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 open_to_lock_owner4 struct open_to_lock_owner4 { seqid4 open_seqid; stateid4 open_stateid; seqid4 lock_seqid; lock_owner4 lock_owner; }; @@ -960,47 +962,46 @@ This structure is used for the various state sharing mechanisms between the client and server. For the client, this data structure 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 [RFC1831] and [RFC1832]. The RPCSEC_GSS security flavor as defined in [RFC2203] 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 [RFC1700] 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 [RFC1833]; this will allow NFS to transit firewalls. - The transport used by the RPC service for the NFS version 4 protocol - MUST provide congestion control comparable to that defined for TCP in - [RFC2581]. If the operating environment implements TCP, the NFS - version 4 protocol SHOULD be supported over TCP. The NFS client and - server MAY use other transports if they support congestion control as - defined above and in those cases a mechanism may be provided to - override TCP usage in favor of another transport. + 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 SHOULD support + operation over the TCP 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. 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 [Floyd]. @@ -1010,34 +1011,34 @@ 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 o The procedure being retried is the NULL procedure - Since transports, including TCP, do not always synchronously inform a - peer when the other peer has broken the connection (for example, when + Since reliable transports, such as TCP, do not always synchronously + inform a peer when the other peer has broken the connection (for + example, when an NFS server reboots), so the NFS version 4 client may -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - an NFS server reboots), so the NFS version 4 client may want to - actively "probe" the connection to see if has been broken. Use of - the NULL procedure is one recommended way to do so. So, when a - client experiences a remote procedure call timeout (of some arbitrary - implementation specific amount), rather than retrying the remote - procedure call, it could instead issue a NULL procedure call to the - server. If the server has died, the transport connection break will - eventually be indicated to the NFS version 4 client. The client can - then reconnect, and then retry the original request. If the NULL + want to actively "probe" the connection to see if has been broken. + Use of the NULL procedure is one recommended way to do so. So, when + a client experiences a remote procedure call timeout (of some + arbitrary implementation specific amount), rather than retrying the + remote procedure call, it could instead issue a NULL procedure call + to the server. If the server has died, the transport connection break + will eventually be indicated to the NFS version 4 client. The client + can then reconnect, and then retry the original request. If the NULL procedure call gets a response, the connection has not broken. The client can decide to wait longer for the original request's response, or it can break the transport connection and reconnect before re- sending the original request. For callbacks from the server to the client, the same rules apply, but the server doing the callback becomes the client, and the client receiving the callback becomes the server. 3.2. Security Flavors @@ -1066,24 +1067,24 @@ 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 1 2 3 4 5 + ----------------------------------------------------------------------- -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - ----------------------------------------------------------------------- 390003 krb5 1.2.840.113554.1.2.2 DES MAC MD5 rpc_gss_svc_none 390004 krb5i 1.2.840.113554.1.2.2 DES MAC MD5 rpc_gss_svc_integrity 390005 krb5p 1.2.840.113554.1.2.2 DES MAC MD5 rpc_gss_svc_privacy for integrity, and 56 bit DES 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 @@ -1120,25 +1121,24 @@ 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 [RFC2025] 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 [RFC2847] for more - -Draft Specification NFS version 4 Protocol August 2002 - details. +Draft Specification NFS version 4 Protocol September 2002 + 3.2.1.3. SPKM-3 as a security triple The SPKM-3 GSS-API mechanism as described in [RFC2847] MUST be implemented and provide the following security triples. The definition of the columns matches the previous subsection "Kerberos V5 as security triple". 1 2 3 4 5 ----------------------------------------------------------------------- 390009 spkm3 1.3.6.1.5.5.1.3 negotiated rpc_gss_svc_none @@ -1170,27 +1170,28 @@ 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 the section "Security Considerations" for further discussion. -Draft Specification NFS version 4 Protocol August 2002 - 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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. 3.3.2. Security Error 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 @@ -1207,43 +1208,43 @@ 3.4. 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. - AUTH_SYS has no notions of mutual authentation or a server principal, - so the callback from the server simply uses the AUTH_SYS credential - that the user used when he set up the delegation. + AUTH_SYS has no notions of mutual authentication or a server + principal, so the callback from the server simply uses the AUTH_SYS + credential that the user used when he set up the delegation. For AUTH_DH, one commonly used convention is that the server uses the credential corresponding to this AUTH_DH principal: unix.host@domain where host and domain are variables corresponding to the name of server host and directory services domain in which it lives such as a Network Information System domain or a DNS domain. Because LIPKEY is layered over SPKM-3, it is permissible for the server to use SPKM-3 and not LIPKEY for the callback even if the - -Draft Specification NFS version 4 Protocol August 2002 - client used LIPKEY for SETCLIENTID. Regardless of what security mechanism under RPCSEC_GSS is being used, the NFS server, MUST identify itself in GSS-API via a GSS_C_NT_HOSTBASED_SERVICE name type. GSS_C_NT_HOSTBASED_SERVICE + +Draft Specification NFS version 4 Protocol September 2002 + names are of the form: service@hostname For NFS, the "service" element is nfs Implementations of security mechanisms will convert nfs@hostname to various different forms. For Kerberos V5 and LIPKEY, the following @@ -1277,29 +1278,26 @@ the SETCLIENTID operation. From an administrative perspective, having a user name, password, and certificate for both the client and server is redundant. o LIPKEY was intended to minimize additional infrastructure requirements beyond a certificate for the target, and the expectation is that existing password infrastructure can be leveraged for the initiator. In some environments, a per-host password does not exist yet. If certificates are used for any per-host principals, then additional password infrastructure is - -Draft Specification NFS version 4 Protocol August 2002 - not needed. o In cases when a host is both an NFS client and server, it can share the same per-host certificate. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 4. Filehandles The filehandle in the NFS protocol is a per server unique identifier 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 @@ -1337,21 +1335,21 @@ 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". 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 and server filesystem object. The client may not make any assumptions about this binding. The client uses the PUBLIC filehandle via the PUTPUBFH operation. 4.2. Filehandle Types @@ -1387,24 +1385,24 @@ opaque. The client stores filehandles for use in a later request and can compare two filehandles from the same server for equality by 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 assumpions which might cause + and in such cases, avoid making invalid assumptions which might cause incorrect behavior. Further discussion of filehandle and attribute -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 comparison in the context of data caching is presented in the section "Data Caching and File Identity". 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 @@ -1441,21 +1439,21 @@ server should return NFS4ERR_STALE to the client (as is the case for persistent filehandles). In all other cases where the server determines that a volatile filehandle can no longer be used, it should return an error of NFS4ERR_FHEXPIRED. The mandatory attribute "fh_expire_type" is used by the client to determine what type of filehandle the server is providing for a particular filesystem. This attribute is a bitmask with the following values: -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 FH4_PERSISTENT The value of FH4_PERSISTENT is used to indicate a persistent filehandle, which is valid until the object is removed from the filesystem. The server will not return NFS4ERR_FHEXPIRED for this filehandle. FH4_PERSISTENT is defined as a value in which none of the bits specified below are set. FH4_VOLATILE_ANY The filehandle may expire at any time, except as specifically @@ -1491,42 +1489,35 @@ but not all filehandles upon migration (e.g. all but those that are open), FH4_VOLATILE_ANY (in this case with FH4_NOEXPIRE_WITH_OPEN) is a better choice since the client may not assume that all filehandles will expire when migration occurs, and it is likely that additional expirations will occur (as a result of file CLOSE) that are separated in time from the migration event itself. 4.2.4. One Method of Constructing a Volatile Filehandle - As mentioned, in some instances a filehandle is stale (no longer - valid; perhaps because the file was removed from the server) or it is - expired (the underlying file is valid but since the filehandle is - -Draft Specification NFS version 4 Protocol August 2002 - - volatile, it may have expired). Thus the server needs to be able to - return NFS4ERR_STALE in the former case and NFS4ERR_FHEXPIRED in the - latter case. This can be done by careful construction of the volatile - filehandle. One possible implementation follows. - A volatile filehandle, while opaque to the client could contain: [volatile bit = 1 | server boot time | slot | generation number] +Draft Specification NFS version 4 Protocol September 2002 + o slot is an index in the server volatile filehandle table o generation number is the generation number for the table entry/slot - If the server boot time is less than the current server boot time, - return NFS4ERR_FHEXPIRED. If slot is out of range, return + When the client presents a volatile filehandle, the server makes the + following checks, which assume that the check for the volatile bit + has passed. If the server boot time is less than the current server + boot time, return NFS4ERR_FHEXPIRED. If slot is out of range, return NFS4ERR_BADHANDLE. If the generation number does not match, return NFS4ERR_FHEXPIRED. When the server reboots, the table is gone (it is volatile). If volatile bit is 0, then it is a persistent filehandle with a different structure following it. 4.3. Client Recovery from Filehandle Expiration @@ -1547,34 +1538,34 @@ from the filesystem, obviously the client will not be able to recover from the expired filehandle. It is also possible that the expired filehandle refers to a file that has been renamed. If the file was renamed by another client, again it is possible that the original client will not be able to recover. However, in the case that the client itself is renaming the file and the file is open, it is possible that the client may be able to recover. The client can determine the new path name based on the processing of the rename request. The client can then regenerate the - -Draft Specification NFS version 4 Protocol August 2002 - new filehandle based on the new path name. The client could also use the compound operation mechanism to construct a set of operations like: RENAME A B LOOKUP B GETFH Note that the COMPOUND procedure does not provide atomicity. This example only reduces the overhead of recovering from an expired + +Draft Specification NFS version 4 Protocol September 2002 + filehandle. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 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 @@ -1613,21 +1604,21 @@ 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 deliberately small since servers must do whatever it takes to support 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 both needed by a large number of clients and is not otherwise -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -1664,21 +1655,21 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. It is recommended that servers support arbitrary named attributes. A @@ -1694,50 +1685,52 @@ IETF standards track documents. See the section "IANA Considerations" 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 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 below because they - are write-only attributes used in a special instance of SETATTR. + 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, 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 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + + mounted_on_fileid For quota_avail_hard, quota_avail_soft, and quota_used see their definitions below for the appropriate classification. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 5.5. Mandatory Attributes - Definitions Name # DataType Access Description ___________________________________________________________________ supp_attr 0 bitmap READ The bit vector which would retrieve all mandatory and recommended attributes that are supported for @@ -1771,25 +1764,24 @@ 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 + size 4 uint64 R/W The size of the object in bytes. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -1799,39 +1791,38 @@ 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 + 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). -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 5.6. Recommended Attributes - Definitions Name # 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 @@ -1847,43 +1838,44 @@ cansettime 15 bool READ True, if the server 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 case + filesystem are case insensitive. case_preserving 17 bool READ True, if filename case on this - filesystem preserved. + 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). -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -1922,36 +1914,35 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 + 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 @@ -1975,21 +1966,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 quota_avail_hard 38 uint64 READ For definition see "Quota Attributes" section below. quota_avail_soft 39 uint64 READ For definition see "Quota Attributes" section below. quota_used 40 uint64 READ For definition see @@ -2025,97 +2016,96 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 + 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 R/W The time of last + 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 5.7. Time Access 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. - Whenever the file object resides on a writeable 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 satisifying 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. + 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. 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 [RFC2624] provides additional rationale. It is expected that the client and server will have their own local representation of owner and @@ -2134,21 +2124,21 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -2189,21 +2179,21 @@ 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 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 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -2240,21 +2230,21 @@ allocations to other files or directories. 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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- filesystem or may be "choose the set with the smallest quota". @@ -2284,30 +2274,35 @@ 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 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 requestor's access, and instead are for - triggering events as a result of a requestor's access attempt. + 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, all AUDIT and ALARM ACEs are processed until end of the - ACL. + 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 - The NFS version 4 ACL model is quite rich. Some server platforms may - provide access control functionality that goes beyond the UNIX-style +Draft Specification NFS version 4 Protocol September 2002 -Draft Specification NFS version 4 Protocol August 2002 + MODE4_*OTH bits will map to EVERYONE@ ACEs that unambiguously specify + the requester's access. + The NFS version 4 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. 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 @@ -2337,43 +2332,42 @@ dependent) when any access attempt is made to a file or directory for the access methods specified in acemask4. 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: const ACL4_SUPPORT_ALLOW_ACL = 0x00000001; const ACL4_SUPPORT_DENY_ACL = 0x00000002; + +Draft Specification NFS version 4 Protocol September 2002 + const ACL4_SUPPORT_AUDIT_ACL = 0x00000004; const ACL4_SUPPORT_ALARM_ACL = 0x00000008; The semantics of the "type" field follow the descriptions provided - -Draft Specification NFS version 4 Protocol August 2002 - 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; 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. + 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: @@ -2387,27 +2381,27 @@ 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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 @@ -2441,23 +2435,24 @@ enabled. 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + + and WRITE_DATA are denied. 5.11.3. ACE flag The "flag" field contains values based on the following descriptions. 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. @@ -2484,31 +2479,31 @@ ACE4_SUCCESSFUL_ACCESS_ACE_FLAG 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 prescence, - if any, of the SUCCESS and FAILED flags encountered in the AUDIT or + 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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. 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. @@ -2540,26 +2535,26 @@ 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 There are several special identifiers ("who") which need to be + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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. @@ -2591,26 +2586,26 @@ 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. - The remaining bits are not defined by this protocol and MUST NOT be +Draft Specification NFS version 4 Protocol September 2002 -Draft Specification NFS version 4 Protocol August 2002 + 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. 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. 5.11.6. Mode and ACL Attribute The server that supports both mode and ACL must take care to @@ -2645,25 +2640,26 @@ mounted on the mount point. 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 + +Draft Specification NFS version 4 Protocol September 2002 + described. The mounted_on_fileid attribute corresponds to the fileid that readdir() would have returned as described previously. -Draft Specification NFS version 4 Protocol August 2002 - 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. 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 @@ -2677,21 +2673,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 6. Filesystem Migration and Replication 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). The fs_locations attribute provides a list of filesystem locations. @@ -2730,21 +2726,21 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. 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. @@ -2783,21 +2779,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -2829,21 +2825,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 7. NFS Server Name Space 7.1. 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 @@ -2881,42 +2877,42 @@ 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 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. 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 The DOS and Windows operating environments are sometimes described as - having "multiple roots". filesystems are commonly represented 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 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 @@ -2933,21 +2929,21 @@ 7.6. 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) -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 /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 The server filesystem environment may be constructed in such a way that one filesystem contains a directory which is 'covered' or @@ -2981,41 +2977,42 @@ 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 may effectively hide filesystems from a client that may otherwise have legitimate access. As suggested practice, the server should apply the security policy of - a shared resource in the server's namespace to the ancestors - components of the namespace. For example: + a shared resource in the server's namespace to the components of the + resource's ancestors. For example: / -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 /a/b /a/b/c + The /a/b/c directory is a real filesystem and is the shared resource. The security policy for /a/b/c is Kerberos with integrity. The - server should 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. + 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 8. 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 [XNFS]. There are three components to making this state manageable: o Clear division between client and server @@ -3055,21 +3052,21 @@ 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 For each LOCK request, the client must identify itself to the server. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -3082,81 +3079,81 @@ struct nfs_client_id4 { verifier4 verifier; opaque id; }; The first field, verifier is a client incarnation verifier that is used to detect client reboots. Only if the verifier is different from that the server has previously recorded the client (as identified by the second field f the structure, id) does the server start the - process of cancelling the client's leased state. + process of canceling the client's leased state. The second field, id is a variable length string that uniquely defines the client. There are several considerations for how the client generates the id string: o The string should be unique so that multiple clients do not present the same string. The consequences of two clients presenting the same string range from one client getting an error to one client having its leased state abruptly and - unexpectedly cancelled. + unexpectedly canceled. o The string should be selected so the subsequent incarnations (e.g. reboots) of the same client cause the client to present the same string. The implementor is cautioned from an approach that requires the string to be recorded in a local file because this precludes the use of the implementation in an environment where there is no local disk and all file access is from an NFS version 4 server. o The string should be different for each server network address that the client accesses, rather than common to all server network addresses. The reason is that it may not be possible for the client to tell if same server is listening on multiple network addresses. If the client issues SETCLIENTID with the -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 same id string to each network address of such a server, the server will think it is the same client, and each successive SETCLIENTID will cause the server to begin the process of removing the client's previous leased state. o The algorithm for generating the string should not assume that the client's network address won't change. This includes changes between client incarnations and even changes while the client is stilling running in its current incarnation. This means that if the client includes just the client's and server's network address in the id string, there is a real risk, after the client gives up the network address, that another client, - using a similar algorithm for generate the id string, will - generating a conflicting id string. + using a similar algorithm for generating the id string, will + generate a conflicting id string. Given the above considerations, an example of a well generated id string is one that includes: o The server's network address. o The client's network address. o For a user level NFS version 4 client, it should contain additional information to distinguish the client from other user level clients running on the same host, such as a process id or other unique sequence. o Additional information that tends to be unique, such as one or more of: - - The client machines serial number (for privacy reasons, it is + - The client machine's serial number (for privacy reasons, it is best to perform some one way function on the serial number). - A MAC address. - The timestamp of when the NFS version 4 software was first installed on the client (though this is subject to the previously mentioned caution about using information that is stored in a file, because the file might only be accessible over NFS version 4). @@ -3164,41 +3161,41 @@ the same between client incarnations, this shares the same problem as that of the using the timestamp of the software installation. As a security measure, the server MUST NOT cancel a client's leased state if the principal established the state for a given id string is not the same as the principal issuing the SETCLIENTID. Note that SETCLIENTID and SETCLIENTID_CONFIRM has a secondary purpose -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 of establishing the information the server needs to make callbacks to the client for purpose of supporting delegations. It is permitted to change this information via SETCLIENTID and SETCLIENTID_CONFIRM within the same incarnation of the client without removing the client's leased state. Once a SETCLIENTID and SETCLIENTID_CONFIRM sequence has successfully completed, the client uses the short hand client identifier, of type clientid4, instead of the longer and less compact nfs_client_id4 - structure. This short hand client identfier (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 the - section "Server Failure and Recovery"). + structure. This short hand 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 the section "Server Failure and Recovery"). 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 the next section "lock_owner and stateid Definition" for details). See the detailed descriptions of SETCLIENTID and SETCLIENTID_CONFIRM for a complete specification of the operations. @@ -3218,21 +3215,21 @@ there had been no activity from that client for many minutes. Note that if the id string in a SETCLIENTID request is properly constructed, and if the client takes care to use the same principal for each successive use of SETCLIENTID, then, barring an active denial of service attack, NFS4ERR_CLID_INUSE should never be returned. However, client bugs, server bugs, or perhaps a deliberate change of -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 the principal owner of the id string (such as the case of a client 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 @@ -3271,43 +3268,42 @@ o The stateid was generated by an earlier server instance (i.e. before a server reboot). The error NFS4ERR_STALE_STATEID should be returned. o The stateid was generated by the current server instance but the stateid no longer designates the current locking state for the lockowner-file pair in question (i.e. one or more locking operations has occurred). The error NFS4ERR_OLD_STATEID should be returned. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 This error condition will only occur when the client issues a locking request which changes a stateid while an I/O request that uses that stateid is outstanding. o The stateid was generated by the current server instance but the stateid does not designate a locking state for any active lockowner-file pair. The error NFS4ERR_BAD_STATEID should be returned. This error condition will occur when there has been a logic error on the part of the client or server. This should not happen. One mechanism that may be used to satisfy these requirements is for the server to, o divide the "other" field of each stateid into two fields: - A server verifier which uniquely designates a particular - server - instantiation. + server instantiation. - An index into a table of locking-state structures. 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 @@ -3322,44 +3318,43 @@ 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 constitutes a share reservation) the stateid (previously returned by the server) must be used to indicate what locks, including both record locks and share reservations, are held by the lockowner. If no state is established by the client, either record lock or share - reservation, a stateid of all bits 0 is used. Regardless whether a - stateid of all bits 0, or a stateid returned by the server is used, -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + reservation, a stateid of all bits 0 is used. Regardless whether a + stateid of all bits 0, or a stateid returned by the server is used, if there is a conflicting share reservation or mandatory record lock held on the file, the server MUST refuse to service the READ or WRITE operation. Share reservations are established by OPEN operations and by their nature are mandatory in that when the OPEN denies READ or WRITE operations, that denial results in such operations being rejected with error NFS4ERR_LOCKED. Record locks may be implemented by the server as either mandatory or advisory, or the choice of mandatory or advisory behavior may be determined by the server on the basis of the file being accessed (for example, some UNIX-based servers support a "mandatory lock bit" on the mode attribute such that if set, record locks are required on the file before I/O is possible). When record locks are advisory, they only prevent the granting of conflicting - lock requests and have no effect on READ's or WRITE's. Mandatory + lock requests and have no effect on READs or WRITEs. Mandatory record locks, however, prevent conflicting I/O operations. When they - are attempted, they are rejected with NFS4ERR_LOCKED. Assuming an - operating environment like UNIX that requires it, when the client - gets NFS4ERR_LOCKED on a file it knows it has the proper share + are attempted, they are rejected with NFS4ERR_LOCKED. When the + client gets NFS4ERR_LOCKED on a file it knows it has the proper share reservation for, it will need to issue a LOCK request on the region of the file that includes the region the I/O was to be performed on, with an appropriate locktype (i.e. READ*_LT for a READ operation, WRITE*_LT for a WRITE operation). With NFS version 3, there was no notion of a stateid so there was no way to tell if the application process of the client sending the READ or WRITE operation had also acquired the appropriate record lock on the file. Thus there was no way to implement mandatory locking. With the stateid construct, this barrier has been removed. @@ -3378,47 +3373,46 @@ NFS4ERR_LOCKED. For Windows environments, there are no advisory record locks, so the server always checks for record locks during I/O requests. Thus, the NFS version 4 LOCK operation does not need to distinguish between advisory and mandatory record locks. It is the NFS version 4 server's processing of the READ and WRITE operations that introduces the distinction. - Every stateid other than the special stateid values noted in this - -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + Every stateid other than the special stateid values noted in this section, whether returned by an OPEN-type operation (i.e. OPEN, OPEN_DOWNGRADE), or by a LOCK-type operation (i.e. LOCK or LOCKU), defines an access mode for the file (i.e. READ, WRITE, or READ-WRITE) as established by the original OPEN which began the stateid sequence, - and as modified by subsequent OPEN's and OPEN_DOWNGRADE's within that + and as modified by subsequent OPENs and OPEN_DOWNGRADEs within that stateid sequence. When a READ, WRITE, or SETATTR which specifies the size attribute, is done, the operation is subject to checking against the access mode to verify that the operation is appropriate given the OPEN with which the operation is associated. - In the case of WRITE-type operations (i.e. WRITE's and SETATTR's - which set size), the server must verify that the access mode allows - writing and return an NFS4ERR_OPENMODE error if it does not. In the - case, of READ, the server may perform the corresponding check on the - access mode, or it may choose to allow READ on opens for WRITE only, - to accommodate clients whose write implementation may unavoidably do - reads (e.g. due to buffer cache constraints). However, even if - READ's are allowed in these circumstances, the server MUST still - check for locks that conflict with the READ (e.g. another open - specify denial of READ's). Note that a server which does enforce the - access mode check on READ's need not explicitly check for conflicting - share reservations since the existence of OPEN for read access - guarantees that no conflicting share reservation can exist. + In the case of WRITE-type operations (i.e. WRITEs and SETATTRs which + set size), the server must verify that the access mode allows writing + and return an NFS4ERR_OPENMODE error if it does not. In the case, of + READ, the server may perform the corresponding check on the access + mode, or it may choose to allow READ on opens for WRITE only, to + accommodate clients whose write implementation may unavoidably do + reads (e.g. due to buffer cache constraints). However, even if READs + are allowed in these circumstances, the server MUST still check for + locks that conflict with the READ (e.g. another open specify denial + of READs). Note that a server which does enforce the access mode + check on READs need not explicitly check for conflicting share + reservations since the existence of OPEN for read access guarantees + that no conflicting share reservation can exist. A stateid of all bits 1 (one) MAY allow READ operations to bypass locking checks at the server. However, WRITE operations with a stateid with bits all 1 (one) MUST NOT bypass locking checks and are treated exactly the same as if a stateid of all bits 0 were used. 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 @@ -3432,23 +3426,24 @@ 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 was returned. The first request issued for any given lock_owner is - issued with a sequence number of zero. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + + issued with a sequence number of zero. Note that for requests that contain a sequence number, for each lock_owner, there should be no more than one outstanding request. If a request (r) with a previous sequence number (r < L) is received, it is rejected with the return of error NFS4ERR_BAD_SEQID. Given a properly-functioning client, the response to (r) must have been 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 @@ -3467,42 +3462,42 @@ 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_BAD_STATEID, NFS4ERR_BAD_SEQID, NFS4ERR_BADXDR, + NFS4ERR_RESOURCE, NFS4ERR_NOFILEHANDLE. 8.1.6. 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. +Draft Specification NFS version 4 Protocol September 2002 + 8.1.7. Releasing lock_owner State When a particular lock_owner no longer holds open or file locking - -Draft Specification NFS version 4 Protocol August 2002 - 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. @@ -3536,45 +3531,44 @@ 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 require confirmation. o The server MUST NOT require confirmation on a reclaim-type open (i.e. one specifying claim type CLAIM_PREVIOUS or CLAIM_DELEGATE_PREV). - These constraints are related in that reclaim-type opens are the - only ones in which the server may be required to send a - delegation. For CLAIM_NULL, sending the delegation is optional - while for CLAIM_DELEGATE_CUR, no delegation is sent. +Draft Specification NFS version 4 Protocol September 2002 -Draft Specification NFS version 4 Protocol August 2002 + These constraints are related in that reclaim-type opens are the only + ones in which the server may be required to send a delegation. For + CLAIM_NULL, sending the delegation is optional while for + CLAIM_DELEGATE_CUR, no delegation is sent. Delegations being sent with an open requiring confirmation are troublesome because recovering from non-confirmation adds undue - complexity to the protocol while requiring confirmation on - reclaim-type opens poses difficulties in that the inability to - resolve the status of the reclaim until lease expiration may - make it difficult to have timely determination of the set of - locks being reclaimed (since the grace period may expire). + complexity to the protocol while requiring confirmation on reclaim- + type opens poses difficulties in that the inability to resolve the + status of the reclaim until lease expiration may make it difficult to + have timely determination of the set of locks being reclaimed (since + the grace period may expire). 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. + 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 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 @@ -3589,27 +3583,28 @@ 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. 8.3. 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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. -Draft Specification NFS version 4 Protocol August 2002 - 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 @@ -3641,28 +3636,28 @@ 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 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - that the associated state held at the server, for the client, is still valid. o An OPEN with a valid clientid. o Any operation made with a valid stateid (CLOSE, DELEGPURGE, DELEGRETURN, LOCK, LOCKU, OPEN, OPEN_CONFIRM, OPEN_DOWNGRADE, READ, RENEW, SETATTR, WRITE). This does not include the special stateids of all bits 0 or all bits 1. @@ -3694,28 +3689,27 @@ 8.6. 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. +Draft Specification NFS version 4 Protocol September 2002 + 8.6.1. 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. - -Draft Specification NFS version 4 Protocol August 2002 - 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 verifier is part of the initial SETCLIENTID call made by the client. The server returns a clientid as a result of the SETCLIENTID operation. The client then confirms the use of the clientid with SETCLIENTID_CONFIRM. The clientid in combination with an opaque @@ -3748,28 +3742,28 @@ 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 the section "Client ID") and re-establish the locking state as discussed below. The period of special handling of locking and READs and WRITEs, equal + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - READ and WRITE operations and non-reclaim locking requests (i.e. other LOCK and OPEN operations) with an error of NFS4ERR_GRACE. If the server can reliably determine that granting a non-reclaim request will not conflict with reclamation of locks by other clients, the NFS4ERR_GRACE error does not have to be returned and the non- reclaim client request can be serviced. For the server to be able to service READ and WRITE operations during the grace period, it must again be able to guarantee that no possible conflict could arise between an impending reclaim locking request and the READ or WRITE @@ -3803,28 +3797,28 @@ 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 [Floyd]. 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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 If the duration of a network partition is greater than the lease @@ -3837,54 +3831,172 @@ returning the error NFS4ERR_EXPIRED. Once this error is received, the client will suitably notify the application that held the lock. As a courtesy to the client or as an optimization, the server may continue to hold locks on behalf of a client for which recent communication has extended beyond the lease period. If the server receives a lock or I/O request that conflicts with one of these courtesy locks, the server must free the courtesy lock and grant the new request. - If the server continues to hold locks beyond the expiration of a - client's lease, the server MUST employ a method of recording this - fact in its stable storage. Conflicting lock requests from another - client may be serviced after the lease expiration. There are various - scenarios involving server failure after such an event that require - the storage of these lease expirations or network partitions. One - scenario is as follows: + When a network partition is combined with a server reboot, there are + edge conditions that place requirements on the server in order to + avoid silent data corruption following the server reboot. Two of + these edge conditions are known, and are discussed below. - A client holds a lock at the server and encounters a - network partition and is unable to renew the associated - lease. A second client obtains a conflicting lock and then - frees the lock. After the unlock request by the second - client, the server reboots or reinitializes. Once the - server recovers, the network partition heals and the - original client attempts to reclaim the original lock. + The first edge condition has the following scenario: - In this scenario and without any state information, the server will - allow the reclaim and the client will be in an inconsistent state - because the server or the client has no knowledge of the conflicting - lock. + 1. Client A acquires a lock. - The server may choose to store this lease expiration or network - partitioning state in a way that will only identify the client as a - whole. Note that this may potentially lead to lock reclaims being + 2. Client A and server experience mutual network partition, + such that client A is unable to renew its lease. -Draft Specification NFS version 4 Protocol August 2002 + 3. Client A's lease expires, so server releases lock. - denied unnecessarily because of a mix of conflicting and non- - conflicting locks. The server may also choose to store information - about each lock that has an expired lease with an associated - conflicting lock. The choice of the amount and type of state - information that is stored is left to the implementor. In any case, - the server must have enough state information to enable correct - recovery from multiple partitions and multiple server failures. + 4. Client B acquires a lock that would have conflicted with + that of Client A. + + 5. Client B releases the lock + +Draft Specification NFS version 4 Protocol September 2002 + + 6. Server reboots + + 7. Network partition between client A and server heals. + + 8. Client A issues a RENEW operation, and gets back a + NFS4ERR_STALE_CLIENTID. + + 9. Client A reclaims its lock within the server's grace period. + + Thus, at the final step, the server has erroneously granted client + A's lock reclaim. If client B modified the object the lock was + protecting, client A will experience object corruption. + + The second known edge condition follows: + + 1. Client A acquires a lock. + + 2. Server reboots. + + 3. Client A and server experience mutual network partition, + such that client A is unable to reclaim its lock within the + grace period. + + 4. Server's reclaim grace period ends. Client A has no locks + recorded on server. + + 5. Client B acquires a lock that would have conflicted with + that of Client A. + + 6. Client B releases the lock + + 7. Server reboots a second time + + 8. Network partition between client A and server heals. + + 9. Client A issues a RENEW operation, and gets back a + NFS4ERR_STALE_CLIENTID. + + 10. Client A reclaims its lock within the server's grace period. + + As with the first edge condition, the final step of the scenario of + the second edge condition has the server erroneously granting client + A's lock reclaim. + + Solving the first and second edge conditions requires that the server + either assume after it reboots that edge condition occurs, and thus + return NFS4ERR_NO_GRACE for all reclaim attempts, or that the server + record some information stable storage. The amount of information + the server records in stable storage is in inverse proportion to how + harsh the server wants to be whenever the edge conditions occur. The + server that is completely tolerant of all edge conditions will record + in stable storage every lock that is acquired, removing the lock + +Draft Specification NFS version 4 Protocol September 2002 + + record from stable storage only when the lock is unlocked by the + client and the lock's lockowner advances the sequence number such + that the lock release is not the last stateful event for the + 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 + + 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, + after the server reboots, the record that client A's lease expired + means that another client could have acquired a conflicting record + lock, share reservation, or delegation. Hence the server must reject + a reclaim from client A with the error NFS4ERR_NO_GRACE. + + For the second edge condition, after the server reboots for a second + time, the record that the client had an unexpired record lock, share + reservation, or delegation established before the server's previous + incarnation means that the server must reject a reclaim from client A + with the error NFS4ERR_NO_GRACE. + + Regardless of the level and approach to record keeping, the server + MUST implement one of the following strategies (which apply to + reclaims of share reservations, record locks, and delegations): + + 1. Reject all reclaims with NFS4ERR_NO_GRACE. This is + superharsh, but necessary if the server does not want to + record lock state in stable storage. + + 2. Record sufficient state in stable storage such that all + known edge conditions involving server reboot, including the + two noted in this section, are detected. False positives are + acceptable. Note that at this time, it is not known if there + are other edge conditions. + +Draft Specification NFS version 4 Protocol September 2002 + + In the event, after a server reboot, the server determines + that there is unrecoverable damage or corruption to the the + stable storage, then for all clients and/or locks affected, + the server MUST return NFS4ERR_NO_GRACE. + + A mandate for the client's handling of the NFS4ERR_NO_GRACE error is + outside the scope of this specification, since the strategies for + such handling are very dependent on the client's operating + environment. However, one potential approach is described below. + + 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 the + section, "Data Caching and Revocation" 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 the section "Server Revocation of Locks". 8.7. 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 @@ -3901,94 +4013,95 @@ 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. +Draft Specification NFS version 4 Protocol September 2002 + 8.8. 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 (NFS4ERR_STALE_STATEID or NFS4ERR_STALE_CLIENTID) and the client will proceed with normal crash recovery as described in the previous - -Draft Specification NFS version 4 Protocol August 2002 - section. The second lock revocation event is the inability to renew the lease before expiration. While this is considered a rare or unusual event, the client must be prepared to recover. Both the server and client will be able to detect the failure to renew the lease and are capable of recovering without data corruption. For the server, it tracks the last renewal event serviced for the client and knows when the lease will expire. Similarly, the client must track operations which will renew the lease period. Using the time that each such request was sent and the time that the corresponding reply was received, the client should bound the time that the corresponding renewal could have occurred on the server and thus determine if it is possible that a lease period expiration could have occurred. The third lock revocation event can occur as a result of administrative intervention within the lease period. While this is considered a rare event, it is possible that the server's administrator has decided to release or revoke a particular lock held by the client. As a result of revocation, the client will receive an - error of NFS4ERR_EXPIRED and the error is received within the lease - period for the lock. 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 failed operation. + 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 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. + +Draft Specification NFS version 4 Protocol September 2002 + 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 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 - -Draft Specification NFS version 4 Protocol August 2002 - the OPEN fails the client will fail the application's open request. Pseudo-code definition of the semantics: + if (request.access == 0) + return (NFS4ERR_INVAL) + else if ((request.access & file_state.deny)) || (request.deny & file_state.access)) return (NFS4ERR_DENIED) This checking of share reservations on OPEN is done with no exception for an existing OPEN for the same open_owner. The constants used for the OPEN and OPEN_DOWNGRADE operations for the access and deny fields are as follows: @@ -4005,39 +4118,38 @@ 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. +Draft Specification NFS version 4 Protocol September 2002 + The OPEN operation with the CREATE flag, also subsumes the CREATE operation for regular files as used in previous versions of the NFS protocol. This allows a create with a share to be done atomically. The CLOSE operation removes all share reservations held by the lock_owner on that file. 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, 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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 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. @@ -4057,144 +4169,144 @@ is not a retransmission. o The time that a lockowner is freed by the server due to period with no activity. o All locks for the client are freed as a result of a SETCLIENTID. 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 retranmitted 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. + must be caused by a retransmitted close. When adopting this + +Draft Specification NFS version 4 Protocol September 2002 + + 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 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 OPEN's. Note that - -Draft Specification NFS version 4 Protocol August 2002 - - the client, when issuing the OPEN, may not know that the same file is - in fact being opened. The above only applies if both OPEN's result - in the OPEN'ed object being designated by the same filehandle. + 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 + fact being opened. The above only applies if both OPENs result in + the OPENed object being designated by the same filehandle. When the server chooses to export multiple filehandles corresponding to the same file object and returns different filehandles on two - different OPEN's of the same file object, the server MUST NOT "OR" + different OPENs of the same file object, the server MUST NOT "OR" together the access and deny bits and coalesce the two open files. - Instead the server must maintain separate OPEN's with separate - stateid's and will require separate CLOSE's to free them. + Instead the server must maintain separate OPENs with separate + stateids and will require separate CLOSEs to free them. 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 open's may be smaller (i.e. a proper + 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 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 (server must - wait for leases to expire and grace period 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 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). + +Draft Specification NFS version 4 Protocol September 2002 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 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. -Draft Specification NFS version 4 Protocol August 2002 - To take propagation delay into account, the client should subtract it from lease times (e.g. if the client estimates the one-way propagation delay as 200 msec, then it can assume that the lease is already 200 msec old when it gets it). In addition, it will take another 200 msec to get a response back to the server. So the client must send a lock renewal or write data back to the server 400 msec 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 propogation delays and other network delay + 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 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, stateid's, and - clientid's) is as described below. The handling differs between + 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" 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 + +Draft Specification NFS version 4 Protocol September 2002 + cooperating in the replication and migration of the filesystem. 8.14.1. 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 stateid's + transferring all state, the client will continue to use stateids assigned by the original server. Therefore the new server must - recognize these stateid's as valid. This holds true for the clientid + recognize these stateids as valid. This holds true for the clientid as well. Since responsibility for an entire filesystem is transferred with a migration event, there is no possibility that conflicts will arise on the new server as a result of the transfer of - -Draft Specification NFS version 4 Protocol August 2002 - locks. As part of the transfer of information between servers, leases would be transferred as well. The leases being transferred to the new server will typically have a different expiration time from those for the same client, previously on the old server. To maintain the property that all leases on a given server for a given client expire at the same time, the server should advance the expiration time to the later of the leases being transferred or the leases already present. This allows the client to maintain lease renewal of both @@ -4207,95 +4319,96 @@ 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. 8.14.2. 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, stateid's and clientid's do not have validity across a + 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 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 - -Draft Specification NFS version 4 Protocol August 2002 - lease relocation before those leases expire. To accomplish this, all operations which implicitly renew leases for a client (i.e. OPEN, CLOSE, READ, WRITE, RENEW, LOCK, LOCKT, LOCKU), will return the error NFS4ERR_LEASE_MOVED if responsibility for any of the leases to be renewed has been transferred to a new server. This condition will continue until the client receives an NFS4ERR_MOVED error and the server receives the subsequent GETATTR(fs_locations) for an access to each filesystem for which a lease has been moved to a new server. When a client receives an NFS4ERR_LEASE_MOVED error, it should - perform some operation, such as a RENEW, 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. + 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 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 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). +Draft Specification NFS version 4 Protocol September 2002 + If state has not been transferred transparently (i.e. the client 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 9. 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 @@ -4335,21 +4448,21 @@ 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 the section "Data Caching and File Locking") can severely limit performance. When locking is used to provide -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -4388,21 +4501,21 @@ on them. Preliminary testing of callback functionality by means of a CB_NULL procedure determines whether callbacks can be supported. The CB_NULL procedure checks the continuity of the callback path. A server makes a preliminary assessment of callback availability to a given client and avoids delegating responsibilities until it has determined that callbacks are supported. Because the granting of a delegation is always conditional upon the absence of conflicting access, clients must not assume that a delegation will be granted and they must always be prepared for OPENs to be processed without any -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 delegations being granted. Once granted, a delegation behaves in most ways like a lock. There is an associated lease that is subject to renewal together with all of the other leases held by that client. Unlike locks, an operation by a second client to a delegated file will cause the server to recall a delegation through a callback. @@ -4441,21 +4554,21 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 leases will result in the revocation of record locks and share reservations. Delegations, however, may be treated a bit differently. There will be situations in which delegations will need to be reestablished after a client reboots or restarts. The reason for this is the client may have file data stored locally and this data was associated with the previously held delegations. The client will need to reestablish the appropriate file state on the server. @@ -4495,21 +4608,21 @@ process of handling delegation reclaim reconciles three principles of the NFS version 4 protocol: o Upon reclaim, a client reporting resources assigned to it by an earlier server instance must be granted those resources. o The server has unquestionable authority to determine whether delegations are to be granted and, once granted, whether they are to be continued. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 o The use of callbacks is not to be depended upon until the client has proven its ability to receive them. When a network partition occurs, delegations are subject to freeing by the server when the lease renewal period expires. This is similar to the behavior for locks and share reservations. For delegations, however, the server may extend the period in which conflicting requests are held off. Eventually the occurrence of a conflicting request from another client will cause revocation of the delegation. @@ -4548,21 +4661,21 @@ invalidate the assumptions that those using these facilities depend upon. 9.3.1. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 WRITE operation. Furthermore, in the absence of open delegation (see the section "Open Delegation") 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 @@ -4601,21 +4714,21 @@ written to the file. Hence, this requirement. 9.3.2. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 bytes zero and one. A lock for write on byte zero of the file would represent the right to do READ and WRITE operations on the first region. A lock for write on byte one of the file would represent the right to do READ and WRITE operations on the second region. As long as all applications manipulating the file obey this convention, they @@ -4646,31 +4759,31 @@ unlocked may cause invalid modification to the region outside the unlocked area. This, in turn, may be part of a region locked by another client. Clients can avoid this situation by synchronously performing portions of write operations that overlap that portion (initial or final) that is not a full block. Similarly, invalidating a locked area which is not an integral number of full buffer blocks would require the client to read one or two partial blocks from the server if the revalidation procedure shows that the data which the client possesses may not be valid. - The data that is written to the server as a pre-requisite to the + The data that is written to the server as a prerequisite to the unlocking of a region must be written, at the server, to stable storage. The client may accomplish this either with synchronous writes or by following asynchronous writes with a COMMIT operation. This is required because retransmission of the modified data after a server reboot might conflict with a lock held by another client. A client implementation may choose to accommodate applications which use record locking in non-standard ways (e.g. using a record lock as -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 a global semaphore) by flushing to the server more data upon an LOCKU than is covered by the locked range. This may include modified data within files other than the one for which the unlocks are being done. In such cases, the client must not interfere with applications whose READs and WRITEs are being done only within the bounds of record locks which the application holds. For example, an application locks a single byte of a file and proceeds to write that single byte. A client that chose to handle a LOCKU by flushing all modified data to the server could validly write that single byte in response to an @@ -4696,64 +4809,64 @@ 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 - When clients cache data, the file data needs to 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. + 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 because a filehandle may be constructed on the basis of the object's pathname. Therefore, clients need a reliable method to determine if two filehandles designate the same filesystem object. If clients -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 were simply to assume that all distinct filehandles denote distinct objects and proceed to do data caching on this basis, caching inconsistencies would arise between the distinct client side objects which mapped to the same server side object. By providing a method to differentiate filehandles, the NFS version 4 protocol alleviates a potential functional regression in comparison with the NFS version 3 protocol. Without this method, caching inconsistencies within the same client could occur and this has not been present in previous versions of the NFS protocol. Note that it is possible to have such inconsistencies with applications executing on multiple clients but that is not the issue being addressed here. For the purposes of data caching, the following steps allow an NFS version 4 client to determine whether two distinct filehandles denote the same server side object: - o If GETATTR directed to two filehandles have different values of - the fsid attribute, then the filehandles represent distinct + o If GETATTR directed to two filehandles returns different values + of the fsid attribute, then the filehandles represent distinct objects. o If GETATTR for any file with an fsid that matches the fsid of the two filehandles in question returns a unique_handles attribute with a value of TRUE, then the two objects are distinct. o If GETATTR directed to the two filehandles does not return the - fileid attribute for one or both of the handles, then it cannot - be determined whether the two objects are the same. Therefore, + 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 @@ -4762,21 +4875,21 @@ 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 set of conditions that servers might use in deciding whether OPEN should be delegated: -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 o The client must be able to respond to the server's callback requests. The server will use the CB_NULL procedure for a test of callback ability. o The client must have responded properly to previous recalls. o There must be no current open conflicting with the requested delegation. @@ -4816,21 +4929,21 @@ 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 the section "Open Delegation and Data Caching") -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -4866,21 +4979,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 9.4.1. 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 @@ -4921,21 +5034,21 @@ The server can recall delegations as a result of managing the available filesystem space. The client should abide by the server's state space limits for delegations. If the client exceeds the stated limits for the delegation, the server's behavior is undefined. Based on server conditions, quotas or available filesystem space, the server may grant write open delegations with very restrictive space limitations. The limitations may be defined in a way that will always force modified data to be flushed to the server on close. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -4967,92 +5080,151 @@ Since CB_GETATTR is being used to satisfy another client's GETATTR request, the server only needs to know if the client holding the delegation has a modified version of the file. If the client's copy of the delegated file is not modified (data or size), the server can satisfy the second client's GETATTR request from the attributes stored locally at the server. If the file is modified, the server only needs to know about this modified state. If the server determines that the file is currently modified, it will respond to the second client's GETATTR as if the file had been modified locally - at the server. This means that the server will take the current time - and apply it to the construction of attributes like change and - time_modify. + at the server. Since the form of the change attribute is determined by the server and is opaque to the client, the client and server need to agree on a - -Draft Specification NFS version 4 Protocol August 2002 - method of communicating the modified state of the file. For the size attribute, the client will report its current view of the file size. + +Draft Specification NFS version 4 Protocol September 2002 + For the change attribute, the handling is more involved. For the client, the following steps will be taken when receiving a write delegation: o The value of the change attribute will be obtained from the server and cached. Let this value be represented by c. o The client will create a value greater than c that will be used for communicating modified data is held at the client. Let this value be represented by d. o When the client is queried via CB_GETATTR for the change attribute, it checks to see if it holds modified data. If the file is modified, the value d is returned for the change attribute value. If this file is not currently modified, the client returns the value c for the change attribute. - While the change attribute is opaque to client in the sense that it - has no idea what units of time, if any, the server is counting change - with, it is not opaque in that the client has to treat it as an - integer, and the server has to be able to see the results of the - client's changes to that integer. Therefore, the server MUST encode - the change attribute in network order when sending it to the client, - the client MUST decode it from network order to its native order when - receiving it, and the client MUST encode it network order when - sending it to the server. For this reason, change is defined as an - integer, rather than an opaque array of octets. + For simplicity of implementation, the client MAY for each CB_GETATTR + return the same value d. This is true even if, between successive + CB_GETATTR operations, the client again modifies in the file's data + or metadata in its cache. The client can return the same value + because the only requirement is that the client be able to indicate + to the server that the client holds modified data. Therefore, the + value of d may always be c + 1. + + While the change attribute is opaque to the client in the sense that + it has no idea what units of time, if any, the server is counting + change with, it is not opaque in that the client has to treat it as + an unsigned integer, and the server has to be able to see the results + of the client's changes to that integer. Therefore, the server MUST + encode the change attribute in network order when sending it to the + client. The client MUST decode it from network order to its native + order when receiving it and the client MUST encode it network order + when sending it to the server. For this reason, change is defined as + an unsigned integer rather than an opaque array of octets. For the server, the following steps will be taken when providing a write delegation: - o On providing a write delegation, the server will cache a copy of - the change attribute. Let this value be represented by sc. + o Upon providing a write delegation, the server will cache a copy + of the change attribute in the data structure it uses to record + the delegation. Let this value be represented by sc. - o The server obtains the change attribute from the client. Let - this value be cc. + o When a second client sends a GETATTR operation on the same file + to the server, the server obtains the change attribute from the + first client. Let this value be cc. o If the value cc is equal to sc, the file is not modified and the - server returns the current values for change and time_modify - (for example) to the client requesting GETATTR. + server returns the current values for change, time_metadata, and + time_modify (for example) to the second client. + +Draft Specification NFS version 4 Protocol September 2002 o If the value cc is NOT equal to sc, the file is currently - modified at the client and most likely will be modified at the - server at a future time. The server then uses the current time - to construct attributes values for change and time_modify and - returns those values to the requestor. + modified at the first client and most likely will be modified at + the server at a future time. The server then uses its current + time to construct attribute values for time_metadata and + time_modify. A new value of sc, which we will call nsc, is + computed by the server, such that nsc >= sc + 1. The server + then returns the constructed time_metadata, time_modify, and nsc + values to the requester. The server replaces sc in the + delegation record with nsc. To prevent the possibility of + time_modify, time_metadata, and change from appearing to go + backward (which would happen if the client holding the + delegation fails to write its modified data to the server before + the delegation is revoked or returned), the server SHOULD update + the file's metadata record with the constructed attribute + values. For reasons of reasonable performance, committing the + constructed attribute values to stable storage is OPTIONAL. + + As discussed earlier in this section, the client MAY return the + same cc value on subsequent CB_GETATTR calls, even if the file + was modified in the client's cache yet again between successive + CB_GETATTR calls. Therefore, the server must assume that the + file has been modified yet again, and MUST take care to ensure + that the new nsc it constructs and returns is greater than the + previous nsc it returned. An example implementation's + delegation record would satisfy this mandate by including a + boolean field (let us call it "modified") that is set to false + when the delegation is granted, and an sc value set at the time + of grant to the change attribute value. The modified field would + be set to true the first time cc != sc, and would stay true + until the delegation is returned or revoked. The processing for + constructing nsc, time_modify, and time_metadata would use this + pseudo code: + + if (!modified) { + do CB_GETATTR for change and size; + + if (cc != sc) + modified = TRUE; } else { + do CB_GETATTR for size; } + + if (modified) { + sc = sc + 1; + time_modify = time_metadata = current_time; + update sc, time_modify, time_metadata into file's metadata; + } + + return to client (that sent GETATTR) the attributes + it requested, but make sure size comes from what + CB_GETATTR returned. Do not update the file's metadata + with the client's modified size. o In the case that the file attribute size is different than the -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 server's current value, the server treats this as a modification regardless of the value of the change attribute retrieved via 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 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 @@ -5076,27 +5248,27 @@ same updates must be done whenever a client chooses to return a delegation voluntarily. The following items of state need to be dealt with: o If the file associated with the delegation is no longer open and 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 + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - delegation stateid so that the client can establish the appropriate rights to perform the OPEN. (see the section "Operation 18: OPEN" 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 @@ -5131,29 +5303,76 @@ constraints) make that desirable. Generally, however, the fact that the actual open state of the file may continue to change makes it not worthwhile to send information about opens and 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 + +Draft Specification NFS version 4 Protocol September 2002 + performed either in previous requests or in previous operations in the same COMPOUND request. -Draft Specification NFS version 4 Protocol August 2002 +9.4.5. Clients that Fail to Honor Delegation Recalls -9.4.5. Delegation Revocation + 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 + respond to the recall might also be sending other NFS requests, + including those that renew the lease before the lease expires. + Without returning an error for those lease renewing operations, the + server leads the client to believe that the delegation it has is in + force. + + This difficulty is solved by the following rules: + + o When the callback path is down, the server MUST NOT revoke the + delegation if one of the following occurs: + + - The client has issued a RENEW operation and the server has + returned an NFS4ERR_CB_PATH_DOWN error. The server MUST renew + the lease for any record locks and share reservations the + client has that the server has known about (as opposed to those + locks and share reservations the client has established but not + yet sent to the server, due to the delegation). The server + SHOULD give the client a reasonable time to return its + delegations to the server before revoking the client's + delegations. + + - The client has not issued a RENEW operation for some period of + 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 At the point a delegation is revoked, if there are associated opens on the client, the applications holding these opens need to be + +Draft Specification NFS version 4 Protocol September 2002 + 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 the section "Revocation Recovery for Write Open Delegation" for additional details. @@ -5186,27 +5405,27 @@ 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 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 - -Draft Specification NFS version 4 Protocol August 2002 - 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 + +Draft Specification NFS version 4 Protocol September 2002 + or administrator is notified may be necessary. Logging and console messages are typical examples. If there is modified data on the client, it must not be flushed normally to the server. A client may attempt to provide a copy of the file data as modified during the delegation under a different name in the filesystem name space to ease recovery. Note that when the client can determine that the file has not been modified by any other client, or when the client has a complete cached copy of file in question, such a saved copy of the client's view of the file may @@ -5240,25 +5459,26 @@ cached. The exception to this are modifications to attributes that are intimately connected with data caching. Therefore, extending a file by writing data to the local data cache is reflected immediately in the size as seen on the client without this change being immediately reflected on the server. Normally such changes are not propagated directly to the server but when the modified data is flushed to the server, analogous attribute changes are made on the server. When open delegation is in effect, the modified attributes may be returned to the server in the response to a CB_RECALL call. -Draft Specification NFS version 4 Protocol August 2002 - The result of local caching of attributes is that the attribute caches maintained on individual clients will not be coherent. Changes made in one order on the server may be seen in a different order on + +Draft Specification NFS version 4 Protocol September 2002 + one client and in a third order on a different client. The typical filesystem application programming interfaces do not provide means to atomically modify or interrogate attributes for multiple files at the same time. The following rules provide an environment where the potential incoherences mentioned above can be reasonably managed. These rules are derived from the practice of previous NFS protocols. o All attributes for a given file (per-fsid attributes excepted) @@ -5294,43 +5514,154 @@ The client may maintain a cache of modified attributes for those attributes intimately connected with data of modified regular files (size, time_modify, and change). Other than those three attributes, the client MUST NOT maintain a cache of modified attributes. Instead, attribute changes are immediately sent to the server. In some operating environments, the equivalent to time_access is expected to be implicitly updated by each read of the content of the file object. If an NFS client is caching the content of a file object, whether it is a regular file, directory, or symbolic link, - -Draft Specification NFS version 4 Protocol August 2002 - the client SHOULD NOT update the time_access attribute (via SETATTR or a small READ or READDIR request) on the server with each read that is satisfied from cache. The reason is that this can defeat the + +Draft Specification NFS version 4 Protocol September 2002 + performance benefits of caching content, especially since an explicit SETATTR of time_access may alter the change attribute on the server. If the change attribute changes, clients that are caching the content will think the content has changed, and will re-read unmodified data from the server. Nor is the client encouraged to maintain a modified version of time_access in its cache, since this would mean that the 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. Name Caching +9.7. 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 + fault, the relevant attributes of the file that are used to detect + access and modification (time_access, time_metadata, time_modify, and + change) will be updated. However, in many operating environments, + when page faults are not required these attributes will not be + updated on reads or updates to the file via memory access (regardless + whether the file is local file or is being access remotely). A + client or server MAY fail to update attributes of a file that is + being accessed via memory mapped I/O. This has several implications: + + o If there is an application on the server that has memory mapped + a file that a client is also accessing, the client may not be + able to get a consistent value of the change attribute to + determine whether its cache is stale or not. A server that + knows that the file is memory mapped could always + pessimistically return updated values for change so as to force + the application to always get the most up to date data and + metadata for the file. However, due to the negative performance + implications of this, such behavior is OPTIONAL. + + o If the memory mapped file is not being modified on the server, + and instead is just being read by an application via the memory + mapped interface, the client will not see an updated time_access + attribute. However, in many operating environments, neither + will any process running on the server. Thus NFS clients are at + +Draft Specification NFS version 4 Protocol September 2002 + + no disadvantage with respect to local processes. + + o If there is another client that is memory mapping the file, and + if that client is holding a write delegation, the same set of + issues as discussed in the previous two bullet items apply. So, + when a server does a CB_GETATTR to a file that the client has + modified in its cache, the response from CB_GETATTR will not + necessarily be accurate. As discussed earlier, the client's + obligation is to report that the file has been modified since + the delegation was granted, not whether it has been modified + again between successive CB_GETATTR calls, and the server MUST + assume that any file the client has modified in cache has been + modified again between successive CB_GETATTR calls. Depending + on the nature of the client's memory management system, this + weak obligation may not be possible. A client MAY return stale + information in CB_GETATTR whenever the file is memory mapped. + + o The mixture of memory mapping and file locking on the same file + is problematic. Consider the following scenario, where a page + size on each client is 8192 bytes. + + - Client A memory maps first page (8192 bytes) of file X + + - Client B memory maps first page (8192 bytes) of file X + + - Client A write locks first 4096 bytes + + - Client B write locks second 4096 bytes + + - Client A, via a STORE instruction modifies part of its + locked region. + + - Simultaneous to client A, client B issues a STORE on part + of its locked region. + + Here the challenge is for each client to resynchronize to get a + correct view of the first page. In many operating environments, + the virtual memory management systems on each client only know a + page is modified, not that a subset of the page corresponding to + the respective lock regions has been modified. So it is not + possible for each client to do the right thing, which is to only + write to the server that portion of the page that is locked. + For example, if client A simply writes out the page, and then + client B writes out the page, client A's data is lost. + + Moreover, if mandatory locking is enabled on the file, then we + have a different problem. When clients A and B issue the STORE + instructions, the resulting page faults require a record lock on + the entire page. Each client then tries to extend their locked + range to the entire page, which results in a deadlock. + +Draft Specification NFS version 4 Protocol September 2002 + + Communicating the NFS4ERR_DEADLOCK error to a STORE instruction + is difficult at best. + + If a client is locking the entire memory mapped file, there is + no problem with advisory or mandatory record locking, at least + until the client unlocks a region in the middle of the file. + + Given the above issues the following are permitted: + + - Clients and servers MAY deny memory mapping a file they + know there are record locks for. + + - Clients and servers MAY deny a record lock on a file they + know is memory mapped. + + - 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 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. @@ -5345,44 +5676,44 @@ determine whether there have been changes made to the directory by other clients. It does this by using the change attribute as reported before and after the directory operation in the associated change_info4 value returned for the operation. The server is able to communicate to the client whether the change_info4 data is provided atomically with respect to the directory operation. If the change values are provided atomically, the client is then able to compare the pre-operation change value with the change value in the client's name cache. If the comparison indicates that the directory was updated by another client, the name cache associated with the + +Draft Specification NFS version 4 Protocol September 2002 + modified directory is purged from the client. If the comparison indicates no modification, the name cache can be updated on the client to reflect the directory operation and the associated timeout - -Draft Specification NFS version 4 Protocol August 2002 - extended. The post-operation change value needs to be saved as the basis for future change_info4 comparisons. As demonstrated by the scenario above, name caching requires that the client revalidate name cache data by inspecting the change attribute of a directory at the point when the name cache item was cached. This requires that the server update the change attribute for 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. -9.8. Directory Caching +9.9. 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 @@ -5399,36 +5730,36 @@ question, checking the change attribute of the directory with GETATTR is adequate. The lifetime of the cache entry can be extended at these checkpoints. When a client is modifying the directory, the client needs to use the change_info4 data to determine whether there are other clients modifying the directory. If it is determined that no other client modifications are occurring, the client may update its directory cache to reflect its own changes. As demonstrated previously, directory caching requires that the client revalidate directory cache data by inspecting the change + +Draft Specification NFS version 4 Protocol September 2002 + attribute of a directory at the point when the directory was cached. This requires that the server update the change attribute for directories when the contents of the corresponding directory is - -Draft Specification NFS version 4 Protocol August 2002 - 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 10. 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 @@ -5463,21 +5794,21 @@ documented attribute. Since attribute results are specified as an opaque array of per-attribute XDR encoded results, the complexity of adding new attributes in the midst of the current definitions will be too burdensome. 3 Minor versions must not modify the structure of an existing operation's arguments or results. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Again the complexity of handling multiple structure definitions for a single operation is too burdensome. New operations should be added instead of modifying existing structures for a minor version. This rule does not preclude the following adaptations in a minor version. o adding bits to flag fields such as new attributes to @@ -5511,21 +5842,21 @@ the request as an XDR decode error. This approach allows for the obsolescence of an operation while maintaining its structure so that a future minor version can reintroduce the operation. 8.1 Minor versions may declare attributes mandatory to NOT implement. 8.2 Minor versions may declare flag bits or enumeration values as mandatory to NOT implement. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 9 Minor versions may downgrade features from mandatory to recommended, or recommended to optional. 10 Minor versions may upgrade features from optional to recommended or recommended to mandatory. 11 A client and server that support minor version X must support minor versions 0 (zero) through X-1 as well. @@ -5534,21 +5865,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 11. Internationalization The primary issue in which NFS 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 which use various languages. The UTF-8 encoding of the UCS as defined by [ISO10646] allows for this type of access and follows the policy described in "IETF Policy on Character Sets and Languages", @@ -5589,21 +5920,21 @@ could be understood by all clients and servers, and maintaining them in the face of changes would be considerable. A better solution is desirable. If the NFS version 4 protocol used a universal 16 bit or 32 bit character set (or an encoding of a 16 bit or 32 bit character set into octets), then the server and client need not care if the locale of the user accessing the file is different than the locale of the user who created the file. The unique 16 bit or 32 bit encoding of -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 the character allows for determination of what language the character is from and also how to display that character on the client. The server need not know what locales are used. 11.2. Overview of Universal Character Set Standards The previous section makes a case for using a universal character set. This section makes the case for using UTF-8 as the specific universal character set for the NFS version 4 protocol. @@ -5638,21 +5969,21 @@ encoding of UCS characters as described below. UTF-1 Only historical interest; it has been removed from 10646-1 UTF-7 Encodes the entire "repertoire" of UCS "characters using only octets with the higher order bit clear". [RFC2152] describes UTF-7. UTF-7 accomplishes this by reserving one of the 7bit US-ASCII characters as a "shift" character to indicate non-US-ASCII characters. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 UTF-8 Unlike UTF-7, uses all 8 bits of the octets. US-ASCII characters are encoded as before unchanged. Any octet with the high bit cleared can only mean a US-ASCII character. The high bit set means that a UCS character is being encoded. UTF-16 Encodes UCS-4 characters into UCS-2 characters using a reserved range in UCS-2. @@ -5690,21 +6021,21 @@ 0000 0080-0000 07FF 110xxxxx 10xxxxxx 0000 0800-0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx 0001 0000-001F FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx 0020 0000-03FF FFFF 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 0400 0000-7FFF FFFF 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx See [RFC2279] for precise encoding and decoding rules. Note because -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 of UTF-16, the algorithm from Unicode/UCS-2 to UTF-8 needs to account for the reserved range between D800 and DFFF. Note that the 16 bit UCS or Unicode characters require no more than 3 octets to encode into UTF-8 Interestingly, UTF-8 has room to handle characters larger than 31 bits, because the leading octet of form: @@ -5744,37 +6075,37 @@ 11.6. UTF-8 Related Errors 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. Where the client supplied string is valid UTF-8 but contains -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. 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 error 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 12. Error Definitions 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. @@ -5786,20 +6117,25 @@ 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. NFS4ERR_ATTRNOTSUPP An attribute specified is not supported by the server. Does not apply to the GETATTR operation. + NFS4ERR_ADMIN_REVOKED Due to administrator intervention, the + lockowner's record locks, share reservations, + and delegations have been revoked by the + server. + NFS4ERR_BADCHAR A UTF-8 string contains a character which is not supported by the server in the context in which it being used. NFS4ERR_BAD_COOKIE READDIR cookie is stale. NFS4ERR_BADHANDLE Illegal NFS filehandle. The filehandle failed internal consistency checks. NFS4ERR_BADNAME A name string in a request consists of valid @@ -5807,28 +6143,28 @@ the name is not supported by the server as a valid name for current operation. NFS4ERR_BADOWNER An owner, owner_group, or ACL attribute value can not be translated to local representation. NFS4ERR_BADTYPE An attempt was made to create an object of a type not supported by the server. NFS4ERR_BAD_RANGE The range for a LOCK, LOCKT, or LOCKU operation + +Draft Specification NFS version 4 Protocol September 2002 + is not appropriate to the allowable range of offsets for the server. NFS4ERR_BAD_SEQID The sequence number in a locking request is neither the next expected number or the last - -Draft Specification NFS version 4 Protocol August 2002 - number processed. 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. NFS4ERR_BADXDR The server encountered an XDR decoding error while processing an operation. @@ -5863,39 +6199,39 @@ exceeded. NFS4ERR_EXIST File exists. The file specified already exists. NFS4ERR_EXPIRED A lease has expired that is being used in the current operation. NFS4ERR_FBIG File too large. The operation would have caused a file to grow beyond the server's limit. +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_FHEXPIRED The filehandle provided is volatile and has expired at the server. NFS4ERR_FILE_OPEN The operation can not be successfully processed - -Draft Specification NFS version 4 Protocol August 2002 - because a file involved in the operation is currently open. NFS4ERR_GRACE The server is in its recovery or grace period which should match the lease period of the server. 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 attempting to SETATTR a time field on a - server that does not support this operation. + link or specifying a value for an enum field + that is not defined in the protocol (e.g. + nfs_ftype4). NFS4ERR_IO I/O error. A hard error (for example, a disk error) occurred while processing the requested operation. NFS4ERR_ISDIR Is a directory. The caller specified a directory in a non-directory operation. NFS4ERR_LEASE_MOVED A lease being renewed is associated with a filesystem that has been migrated to a new @@ -5917,34 +6253,32 @@ 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. NFS4ERR_MLINK Too many hard links. NFS4ERR_MOVED The filesystem which contains the current filehandle object has been relocated or + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - Relocation". NFS4ERR_NAMETOOLONG The filename in an operation was too long. - NFS4ERR_NODEV No such device. - NFS4ERR_NOENT No such file or directory. The file or directory name specified does not exist. 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). @@ -5974,52 +6308,52 @@ NFS4ERR_OLD_STATEID A stateid which designates the locking state for a lockowner-file at an earlier time was used. 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). +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_OP_ILLEGAL An illegal operation value has been specified in the argop field of a COMPOUND or CB_COMPOUND procedure. -Draft Specification NFS version 4 Protocol August 2002 - 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. - NFS4ERR_READDIR_NOSPC The encoded response to a READDIR request - exceeds the size limit set by the initial - request. - NFS4ERR_RECLAIM_BAD The reclaim provided by the client does not match any of the server's state consistency checks and is bad. NFS4ERR_RECLAIM_CONFLICT The reclaim provided by the client has encountered a conflict and can not be provided. Potentially indicates a misbehaving client. NFS4ERR_RESOURCE For the processing of the COMPOUND procedure, the server may exhaust available resources and - can not continue processing operationss within + 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_RESTOREFH The RESTOREFH operation does not have a saved + filehandle (identified by SAVEFH) to operate + upon. + NFS4ERR_ROFS Read-only filesystem. 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. 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 @@ -6028,46 +6362,48 @@ NFS4ERR_SHARE_DENIED An attempt to OPEN a file with a share reservation has failed because of a share conflict. 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. +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_STALE_CLIENTID A clientid not recognized by the server was used in a locking or SETCLIENTID_CONFIRM request. -Draft Specification NFS version 4 Protocol August 2002 - NFS4ERR_STALE_STATEID A stateid generated by an earlier server instance was used. 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. - NFS4ERR_TOOSMALL Buffer or request is too small. + NFS4ERR_TOOSMALL The encoded response to a READDIR request + exceeds the size limit set by the initial + request. NFS4ERR_WRONGSEC 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. NFS4ERR_XDEV Attempt to do an operation between different fsids. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 13. 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. @@ -6107,21 +6443,21 @@ +-----+--------------+--------+-----------+-----------+-----------+-- and the reply's structure is: +------------+-----+--------+-----------------------+-- |last status | tag | numres | status + op + results | +------------+-----+--------+-----------------------+-- The numops and numres fields, used in the depiction above, represent -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 The server will process the COMPOUND procedure by evaluating each of the operations within the COMPOUND procedure in order. Each @@ -6160,40 +6496,40 @@ 13.3. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14. NFS version 4 Procedures 14.1. Procedure 0: NULL - No Operation SYNOPSIS ARGUMENT @@ -6209,21 +6545,21 @@ 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. ERRORS None. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2. Procedure 1: COMPOUND - Compound Operations SYNOPSIS compoundargs -> compoundres ARGUMENT union nfs_argop4 switch (nfs_opnum4 argop) { @@ -6258,21 +6594,21 @@ 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 procedure is executed. The server 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 In the processing of the COMPOUND procedure, the server may find that it does not have the available resources to execute any or all of the operations within the COMPOUND sequence. In this case, the error NFS4ERR_RESOURCE will be returned for the particular operation within the COMPOUND procedure where the resource exhaustion occurred. This assumes that all previous operations within the COMPOUND sequence have been evaluated successfully. The results for all of the evaluated operations must be returned to the client. @@ -6313,21 +6649,21 @@ the minorversion field is non-zero and the server does not support the minor version, the server returns an error of NFS4ERR_MINOR_VERS_MISMATCH. Therefore, the NFS4ERR_MINOR_VERS_MISMATCH error takes precedence over all other errors. It is possible that the server receives a request that contains an operation that is less than the first legal operation (OP_ACCESS) or greater than the last legal operation (OP_RELEASE_LOCKOWNER). -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 In this case, the server's response will encode the opcode OP_ILLEGAL rather than the illegal opcode of the request. The status field in 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 @@ -6342,21 +6678,21 @@ 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. ERRORS All errors defined in the protocol -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.1. Operation 3: ACCESS - Check Access Rights SYNOPSIS (cfh), accessreq -> supported, accessrights ARGUMENT const ACCESS4_READ = 0x00000001; @@ -6392,21 +6728,21 @@ 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 provided. On success, the current filehandle retains its value. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Note that the supported field will contain only as many values as was originally sent in the arguments. For example, if the client sends an ACCESS operation with only the ACCESS4_READ value set and the server supports this value, the server will return only ACCESS4_READ even if it could have reliably checked other values. The results of this operation are necessarily advisory in nature. A return status of NFS4_OK and the appropriate bit set in the bit mask does not imply that such access will be allowed to the file @@ -6418,22 +6754,21 @@ ACCESS4_READ Read data from file or read a directory. ACCESS4_LOOKUP Look up a name in a directory (no meaning for non- directory objects). ACCESS4_MODIFY Rewrite existing file data or modify existing directory entries. ACCESS4_EXTEND Write new data or add directory entries. - ACCESS4_DELETE Delete an existing directory entry (no meaning for - non-directory objects). + ACCESS4_DELETE Delete an existing directory entry. ACCESS4_EXECUTE Execute file (no meaning for a directory). On success, the current filehandle retains its value. 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 @@ -6445,24 +6780,24 @@ only current file attributes. In the NFS version 2 protocol, the only reliable way to determine whether an operation was allowed was to try it and see if it succeeded or failed. Using the ACCESS operation in the NFS version 4 protocol, the client can ask the server to indicate whether or not one or more classes of operations are permitted. The ACCESS operation is provided to allow clients to check before doing a series of operations which will result in an access failure. The OPEN operation provides a point where the server can verify access + to the file object and method to return that information to the -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - to the file object and method to return that information to the client. The ACCESS operation is still useful for directory operations or for use in the case the UNIX API "access" is used on the client. The information returned by the server in response to an ACCESS call is not permanent. It was correct at the exact time that the server performed the checks, but not necessarily afterwards. The server can revoke access permission at any time. The client should use the effective credentials of the user to @@ -6482,28 +6817,29 @@ check that particular access right. The ACCESS4_DELETE bit in the access mask returned will then be ignored by the client. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.2. Operation 4: CLOSE - Close File SYNOPSIS (cfh), seqid, open_stateid -> open_stateid ARGUMENT struct CLOSE4args { @@ -6537,49 +6873,49 @@ locks would exist after the CLOSE. On success, the current filehandle retains its value. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. ERRORS + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADHANDLE NFS4ERR_BAD_SEQID NFS4ERR_BAD_STATEID NFS4ERR_BADXDR NFS4ERR_DELAY NFS4ERR_EXPIRED NFS4ERR_FHEXPIRED - NFS4ERR_GRACE 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.3. Operation 5: COMMIT - Commit Cached Data SYNOPSIS (cfh), offset, count -> verifier ARGUMENT struct COMMIT4args { @@ -6617,21 +6953,21 @@ The server returns a write verifier upon successful completion of the COMMIT. The write verifier is used by the client to determine if the server has restarted or rebooted between the initial WRITE(s) and the 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 may result in uncommitted data loss as well. On success, the current filehandle retains its value. 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 @@ -6671,21 +7007,21 @@ close. In this case, the client would gather all of the buffers for this file that contain uncommitted data, do the COMMIT operation with an offset of 0 and count of 0, and then free all of those buffers. Any other dirty buffers would be sent to the server in the normal fashion. After a buffer is written by the client with the stable parameter set to UNSTABLE4, the buffer must be considered as modified by the client until the buffer has either been flushed via a COMMIT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 operation or written via a WRITE operation with stable parameter set to FILE_SYNC4 or DATA_SYNC4. This is done to prevent the buffer from being freed and reused before the data can be flushed to stable storage on the server. When a response is returned from either a WRITE or a COMMIT operation and it contains a write verifier that is different than previously returned by the server, the client will need to retransmit all of the buffers containing uncommitted cached data to @@ -6712,21 +7048,21 @@ NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_ISDIR NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.4. Operation 6: CREATE - Create a Non-Regular File Object SYNOPSIS (cfh), name, type, attrs -> (cfh), change_info, attrs_set ARGUMENT union createtype4 switch (nfs_ftype4 type) { @@ -6764,21 +7100,21 @@ 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, -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -6817,53 +7153,54 @@ 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. IMPLEMENTATION -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. 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_NOTSUPP + NFS4ERR_PERM NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.5. Operation 7: DELEGPURGE - Purge Delegations Awaiting Recovery SYNOPSIS clientid -> ARGUMENT struct DELEGPURGE4args { @@ -6897,25 +7234,30 @@ 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. ERRORS NFS4ERR_BADXDR NFS4ERR_NOTSUPP + NFS4ERR_LEASE_MOVED + NFS4ERR_MOVED NFS4ERR_RESOURCE + +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_SERVERFAULT NFS4ERR_STALE_CLIENTID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.6. Operation 8: DELEGRETURN - Return Delegation SYNOPSIS (cfh), stateid -> ARGUMENT struct DELEGRETURN4args { @@ -6934,29 +7276,36 @@ 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. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.7. Operation 9: GETATTR - Get Attributes SYNOPSIS (cfh), attrbits -> attrbits, attrvals ARGUMENT struct GETATTR4args { @@ -6993,40 +7342,40 @@ value 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 IMPLEMENTATION 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.8. Operation 10: GETFH - Get Current Filehandle SYNOPSIS (cfh) -> filehandle ARGUMENT /* CURRENT_FH: */ @@ -7061,28 +7410,28 @@ PUTFH (directory filehandle) LOOKUP (entry name) GETFH ERRORS NFS4ERR_BADHANDLE NFS4ERR_FHEXPIRED NFS4ERR_MOVED -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_NOFILEHANDLE NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.9. Operation 11: LINK - Create Link to a File SYNOPSIS (sfh), (cfh), newname -> (cfh), change_info ARGUMENT struct LINK4args { @@ -7118,21 +7467,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -7168,21 +7517,21 @@ NFS4ERR_NOSPC NFS4ERR_NOTDIR NFS4ERR_NOTSUPP NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_WRONGSEC NFS4ERR_XDEV -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.10. Operation 12: LOCK - Create Lock SYNOPSIS (cfh) locktype, reclaim, offset, length, locker -> stateid ARGUMENT struct open_to_lock_owner4 { @@ -7220,21 +7569,21 @@ locker4 locker; }; RESULT struct LOCK4denied { offset4 offset; length4 length; nfs_lock_type4 locktype; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 lock_owner4 owner; }; struct LOCK4resok { stateid4 lock_stateid; }; union LOCK4res switch (nfsstat4 status) { case NFS4_OK: @@ -7273,21 +7622,21 @@ On success, the current filehandle retains its value. 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -7302,56 +7651,70 @@ bytes already locked by that lock_owner and LOCKU of locks held by that lock_owner (specifying an exactly-matching range and type). Similarly, when the client makes a lock request that amounts to upgrading (changing from a read lock to a write lock) or downgrading (changing from write lock to a read lock) an existing record lock, and the server does not support such a lock, the server will return NFS4ERR_LOCK_NOTSUPP. Such operations may not perfectly reflect the required semantics in the face of conflicting lock requests from other clients. + The locker argument specifies the lock_owner that is associated + with the LOCK request. The locker4 structure is a switched union + that 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. + ERRORS NFS4ERR_ACCESS + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADHANDLE NFS4ERR_BAD_RANGE NFS4ERR_BAD_SEQID NFS4ERR_BAD_STATEID NFS4ERR_BADXDR NFS4ERR_DEADLOCK NFS4ERR_DELAY + +Draft Specification NFS version 4 Protocol September 2002 + 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 - -Draft Specification NFS version 4 Protocol August 2002 - NFS4ERR_RECLAIM_BAD NFS4ERR_RECLAIM_CONFLICT NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_STALE_CLIENTID NFS4ERR_STALE_STATEID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.11. Operation 13: LOCKT - Test For Lock SYNOPSIS (cfh) locktype, offset, length owner -> {void, NFS4ERR_DENIED -> owner} ARGUMENT @@ -7388,21 +7751,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 On success, the current filehandle retains its value. 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. @@ -7435,21 +7798,21 @@ NFS4ERR_ISDIR NFS4ERR_LEASE_MOVED NFS4ERR_LOCK_RANGE NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_STALE_CLIENTID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.12. Operation 14: LOCKU - Unlock File SYNOPSIS (cfh) type, seqid, stateid, offset, length -> stateid ARGUMENT struct LOCKU4args { @@ -7486,54 +7849,54 @@ On success, the current filehandle retains its value. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. 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_CLIENTID NFS4ERR_STALE_STATEID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.13. Operation 15: LOOKUP - Lookup Filename SYNOPSIS (cfh), component -> (cfh) ARGUMENT struct LOOKUP4args { @@ -7563,21 +7926,21 @@ 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. 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): -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 PUTFH (directory filehandle) LOOKUP "pub" GETFH LOOKUP "foo" GETFH LOOKUP "bar" GETFH NFS version 4 servers depart from the semantics of previous NFS @@ -7616,33 +7979,33 @@ NFS4ERR_ACCESS NFS4ERR_BADCHAR NFS4ERR_BADHANDLE NFS4ERR_BADNAME NFS4ERR_BADXDR NFS4ERR_FHEXPIRED NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_MOVED -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_NAMETOOLONG NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE NFS4ERR_NOTDIR NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_SYMLINK NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.14. Operation 16: LOOKUPP - Lookup Parent Directory SYNOPSIS (cfh) -> (cfh) ARGUMENT /* CURRENT_FH: object */ @@ -7669,31 +8032,30 @@ 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. ERRORS NFS4ERR_ACCESS NFS4ERR_BADHANDLE NFS4ERR_FHEXPIRED - NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_MOVED NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE NFS4ERR_NOTDIR NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.15. Operation 17: NVERIFY - Verify Difference in Attributes SYNOPSIS (cfh), fattr -> - ARGUMENT struct NVERIFY4args { @@ -7724,51 +8086,49 @@ 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 READ 0 32767 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_NOTSUPP is returned to - the client. + 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - time_modify_set) is specified, the error NFS4ERR_INVAL is returned to - the client. If both of these conditions apply, the server is free to - return either error. + time_modify_set) is specified, the error NFS4ERR_INVAL is returned + to the client. ERRORS NFS4ERR_ACCESS NFS4ERR_ATTRNOTSUPP NFS4ERR_BADCHAR NFS4ERR_BADHANDLE NFS4ERR_BADXDR NFS4ERR_DELAY NFS4ERR_FHEXPIRED NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTSUPP NFS4ERR_RESOURCE NFS4ERR_SAME NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.16. Operation 18: OPEN - Open a Regular File SYNOPSIS (cfh), seqid, share_access, share_deny, owner, openhow, claim -> (cfh), stateid, cinfo, rflags, open_confirm, attrset delegation ARGUMENT @@ -7807,21 +8167,21 @@ void; }; /* Next definitions used for OPEN delegation */ enum limit_by4 { NFS_LIMIT_SIZE = 1, NFS_LIMIT_BLOCKS = 2 /* others as needed */ }; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 struct nfs_modified_limit4 { uint32_t num_blocks; uint32_t bytes_per_block; }; union nfs_space_limit4 switch (limit_by4 limitby) { /* limit specified as file size */ case NFS_LIMIT_SIZE: uint64_t filesize; @@ -7862,21 +8222,21 @@ * rather than by name. */ case CLAIM_PREVIOUS: /* CURRENT_FH: file being reclaimed */ open_delegation_type4 delegate_type; /* * Right to file based on a delegation granted by the server. * File is specified by name. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 */ case CLAIM_DELEGATE_CUR: /* CURRENT_FH: directory */ open_claim_delegate_cur4 delegate_cur_info; /* Right to file based on a delegation granted to a previous boot * instance of the client. File is specified by name. */ case CLAIM_DELEGATE_PREV: @@ -7915,21 +8275,21 @@ open. */ }; union open_delegation4 switch (open_delegation_type4 delegation_type) { case OPEN_DELEGATE_NONE: void; case OPEN_DELEGATE_READ: open_read_delegation4 read; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 case OPEN_DELEGATE_WRITE: open_write_delegation4 write; }; const OPEN4_RESULT_CONFIRM = 0x00000002; const OPEN4_RESULT_LOCKTYPE_POSIX = 0x00000004; struct OPEN4resok { stateid4 stateid; /* Stateid for open */ @@ -7968,21 +8328,21 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 create of a named attribute is not supported. If the createmode is EXCLUSIVE4 and the current filehandle is a named attribute directory, the server will return EINVAL. UNCHECKED means that the file should be created if a file of that name does not exist and encountering an existing regular file of that name is not an error. For this type of create, createattrs specifies the initial set of attributes for the file. The set of attributes may include any writable attribute valid for regular @@ -8016,33 +8376,33 @@ 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. Upon successful creation, the current filehandle is replaced by that of the new object. The OPEN operation provides for Windows share reservation - capability with the use of the access and deny fields of the OPEN - arguments. The client specifies at OPEN the required access and - 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 + 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - 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 the section on 'Share - Reservations'. + 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 the + section on 'Share Reservations'. 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: @@ -8066,60 +8426,60 @@ recalling a delegation. CLAIM_DELEGATE_PREV The client is claiming a delegation granted to a previous client instance; used after the client reboots. The server MAY support CLAIM_DELEGATE_PREV. If it does support CLAIM_DELEGATE_PREV, SETCLIENTID_CONFIRM MUST NOT remove the client's delegation state, and the - server MUST support the DELEGEPURGE + 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 is Posix like with respect to lock range coalescing. From - this the client can choose to manage file locking state in a way to - handle a mis-match of file locking management. + 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 the section "UTF-8 Related Errors" 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 OPEN's + 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 read-only mode and the OPEN request has specified ACCESS_WRITE or ACCESS_BOTH, the server will return NFS4ERR_ROFS to indicate a read-only filesystem. As with the CREATE operation, the server MUST derive the owner, @@ -8135,21 +8495,21 @@ 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. IMPLEMENTATION The OPEN operation contains support for EXCLUSIVE create. The mechanism is similar to the support in NFS version 3 [RFC1813]. As in NFS version 3, this mechanism provides reliable exclusive -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -8190,95 +8550,98 @@ data to store the verifier. The subsequent SETATTR must not occur in the same COMPOUND request as the OPEN. This separation will guarantee that the exclusive create mechanism will continue to function properly in the face of retransmission of the request. Use of the GUARDED attribute does not provide exactly-once semantics. In particular, if a reply is lost and the server does not detect the retransmission of the request, the operation can fail with NFS4ERR_EXIST, even though the create was performed -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 successfully. The client would use this behavior in the case that the application has not requested an exclusive create but has asked to have the file truncated when the file is opened. In the case of the client timing out and retransmitting the create request, the client can use GUARDED to prevent against a sequence like: create, write, create (retransmitted) from occurring. - For SHARE reservations, the client must specify a value for access - that is one of READ, WRITE, or BOTH. For deny, the client must - specify one of NONE, READ, WRITE, or BOTH. If the client fails to - do this, the server must return NFS4ERR_INVAL. + For SHARE reservations, the client must specify a value for + share_access that is one of READ, WRITE, or BOTH. For share_deny, + the client must specify one of NONE, READ, WRITE, or BOTH. If the + client fails to do this, the server must return NFS4ERR_INVAL. - Based on the access value (READ, WRITE, or BOTH) the client should - check that the requestor has the proper access rights to perform - the specified operation. This would generally be the results of - applying the ACL access rules to the file for the current - requestor. However, just as with the ACCESS operation, the client - should not attempt to second-guess the server's decisions, as - access rights may change and may be subject to server + Based on the share_access value (READ, WRITE, or BOTH) the client + should check that the requester has the proper access rights to + perform the specified operation. This would generally be the + results of applying the ACL access rules to the file for the + current requester. However, just as with the ACCESS operation, the + client should not attempt to second-guess the server's decisions, + as access rights may change and may be subject to server administrative controls outside the ACL framework. If the - requestor is not authorized to READ or WRITE (depending on the - access value), the server must return NFS4ERR_ACCESS. Note that - since the NFS version 4 protocol does not impose any requirement - that READ's and WRITE's issued for an open file have the same - credentials as the OPEN itself, the server still must do - appropriate access checking on the READ's and WRITE's themselves. + requester is not authorized to READ or WRITE (depending on the + share_access value), the server must return NFS4ERR_ACCESS. Note + that since the NFS 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. 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_ISDIR - NFS4ERR_LEASE_MOVED + NFS4ERR_INVAL -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.17. Operation 19: OPENATTR - Open Named Attribute Directory SYNOPSIS (cfh) createdir -> (cfh) ARGUMENT struct OPENATTR4args { @@ -8314,43 +8677,42 @@ attribute directory assumes that the server has implemented named attribute support in this fashion and is not required to do so by this definition. IMPLEMENTATION If the server does not support named attributes for the current filehandle, an error of NFS4ERR_NOTSUPP will be returned to the client. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 ERRORS NFS4ERR_ACCESS NFS4ERR_BADHANDLE NFS4ERR_BADXDR NFS4ERR_DELAY + NFS4ERR_DQUOT NFS4ERR_FHEXPIRED - NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_MOVED NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE NFS4ERR_NOSPC NFS4ERR_NOTSUPP NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE - NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.18. Operation 20: OPEN_CONFIRM - Confirm Open SYNOPSIS (cfh), seqid, stateid-> stateid ARGUMENT struct OPEN_CONFIRM4args { @@ -8387,39 +8749,39 @@ On success, the current filehandle retains its value. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 when to dispose of open_owner4s is an implementation choice. The 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 ensure that this is a new OPEN and not a replay or retransmission. - Servers must not require confirmation on OPEN's that grant + Servers must not require confirmation on OPENs that grant delegations or are doing reclaim operations. See section "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. 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. @@ -8442,44 +8804,45 @@ open_owner4, and it receives an operation on the open_owner4 that has 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 open_owner4 within the lease period. In this case, the OPEN state - is cancelled and disposal of the open_owner4 can occur. + is canceled and disposal of the open_owner4 can occur. ERRORS + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADHANDLE NFS4ERR_BAD_SEQID + NFS4ERR_BAD_STATEID NFS4ERR_BADXDR NFS4ERR_EXPIRED NFS4ERR_FHEXPIRED - NFS4ERR_GRACE NFS4ERR_INVAL NFS4ERR_ISDIR NFS4ERR_MOVED - NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTSUPP + NFS4ERR_OLD_STATEID NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE + NFS4ERR_STALE_STATEID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.19. Operation 21: OPEN_DOWNGRADE - Reduce Open File Access SYNOPSIS (cfh), stateid, seqid, access, deny -> stateid ARGUMENT struct OPEN_DOWNGRADE4args { @@ -8498,59 +8861,61 @@ union OPEN_DOWNGRADE4res switch(nfsstat4 status) { case NFS4_OK: OPEN_DOWNGRADE4resok resok4; default: void; }; DESCRIPTION - This operation is used to adjust the access and deny bits for a - given open. This is necessary when a given lockowner opens the - same file multiple times with different access and deny flags. In - this situation, a close of one of the open's may change the - appropriate access and deny flags to remove bits associated with - open's no longer in effect. + This operation is used to adjust the share_access and share_deny + bits for a given open. This is necessary when a given lockowner + 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 access and deny bits specified in this operation replace the - current ones for the specified open file. The access and deny bits - specified must be exactly equal to the union of the access and deny - bits specified for some subset of the OPEN's in effect for current - openowner on the current file. If that constraint is not - respected, the error NFS4ERR_INVAL should be returned. Since - access and deny bits are subsets of those already granted, it is - not possible for this request to be denied because of conflicting - share reservations. + 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. +Draft Specification NFS version 4 Protocol September 2002 -Draft Specification NFS version 4 Protocol August 2002 + On success, the current filehandle retains its value. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.20. Operation 22: PUTFH - Set Current Filehandle SYNOPSIS filehandle -> (cfh) ARGUMENT struct PUTFH4args { @@ -8562,41 +8927,41 @@ struct PUTFH4res { /* CURRENT_FH: */ nfsstat4 status; }; DESCRIPTION Replaces the current filehandle with the filehandle provided as an argument. - If the security mechanism used by the requestor does not meet the + 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. IMPLEMENTATION Commonly used as the first operator in an NFS request to set the context for following operations. ERRORS NFS4ERR_BADHANDLE NFS4ERR_BADXDR NFS4ERR_FHEXPIRED NFS4ERR_MOVED NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.21. Operation 23: PUTPUBFH - Set Public Filehandle SYNOPSIS - -> (cfh) ARGUMENT void; @@ -8633,21 +8998,21 @@ 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. [RFC2224] 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 [RFC2224] 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 @@ -8660,21 +9025,21 @@ 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. ERRORS NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.22. Operation 24: PUTROOTFH - Set Root Filehandle SYNOPSIS - -> (cfh) ARGUMENT void; @@ -8698,21 +9063,21 @@ Commonly used as the first operator in an NFS request to set the context for following operations. ERRORS NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.23. Operation 25: READ - Read from File SYNOPSIS (cfh), stateid, offset, count -> eof, data ARGUMENT struct READ4args { @@ -8750,21 +9115,21 @@ checking. If the client specifies a count value of 0 (zero), the READ succeeds and returns 0 (zero) bytes of data again subject to access permissions checking. The server may choose to return fewer bytes than specified by the client. The client needs to check for this condition and handle the condition appropriately. The stateid value for a READ request represents a value returned -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 from a previous record lock or share reservation request. The stateid is used by the server to verify that the associated share reservation and any record locks are still valid and to update lease timeouts for the client. If the read ended at the end-of-file (formally, in a correctly formed READ request, if offset + count is equal to the size of the file), or the read request extends beyond the size of the file (if offset + count is greater than the size of the file), eof is @@ -8793,55 +9158,56 @@ 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 the read request return. Server resource exhaustion may also occur 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, server will return an - NFS4ERR_LOCKED error. The client should try to get appropriate + 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. + READ. When the READ completes, the client should release the + record lock via LOCKU. ERRORS NFS4ERR_ACCESS -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADHANDLE NFS4ERR_BAD_STATEID NFS4ERR_BADXDR NFS4ERR_DELAY NFS4ERR_EXPIRED NFS4ERR_FHEXPIRED NFS4ERR_GRACE - NFS4ERR_INVAL 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.24. Operation 26: READDIR - Read Directory SYNOPSIS (cfh), cookie, cookieverf, dircount, maxcount, attr_request -> cookieverf { cookie, name, attrs } ARGUMENT struct READDIR4args { @@ -8878,21 +9244,21 @@ default: void; }; 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 cookie value that is provided by the server on a previous READDIR request. @@ -8909,66 +9275,65 @@ This value represents the length of the names of the directory entries and the cookie value for these entries. This length represents the XDR encoding of the data (names and cookies) and not the length in the native format of the server. The maxcount value of the argument is the maximum number of bytes for the result. This maximum size represents all of the data being returned within the READDIR4resok structure and includes the XDR overhead. The server may return less data. If the server is unable to return a single directory entry within the maxcount - limit, the error NFS4ERR_READDIR_NOSPC will be returned to the - client. + limit, the error NFS4ERR_TOOSMALL will be returned to the client. - Finally, attrbits represents the list of attributes to be returned - for each directory entry supplied by the server. + Finally, attr_request represents the list of attributes to be + returned for each directory entry supplied by the server. On successful return, the server's response will provide a list of directory entries. Each of these entries contains the name of the directory entry, a cookie value for that entry, and the associated attributes as requested. The "eof" flag has a value of TRUE if there are no more entries in the directory. The cookie value is only meaningful to the server and is used as a "bookmark" for the directory entry. As mentioned, this cookie is used by the client for subsequent READDIR operations so that it may continue reading a directory. The cookie is similar in concept to a READ offset but should not be interpreted as such by the client. Ideally, the cookie value should not change if the directory is modified since the client may be caching these values. In some cases, the server may encounter an error while obtaining the attributes for a directory entry. Instead of returning an error for the entire READDIR operation, the server can instead + return the attribute 'fattr4_rdattr_error'. With this, the server -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - return the attribute 'fattr4_rdattr_error'. With this, the server is able to communicate the failure to the client and not fail the entire operation in the instance of what might be a transient failure. Obviously, the client must request the fattr4_rdattr_error attribute for this method to work properly. If the client does not request the attribute, the server has no choice but to return failure for the entire READDIR operation. For some filesystem environments, the directory entries "." and ".." have special meaning and in other environments, they may not. If the server supports these special entries within a directory, they should not be returned to the client as part of the READDIR response. To enable some client environments, the cookie values of 0, 1, and 2 are to be considered reserved. Note that the UNIX client will use these 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 + and for READDIR results cookie values of 0, 1, and 2 should not be returned. On success, the current filehandle retains its value. 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 @@ -8986,24 +9351,24 @@ values that may become stale. It should be a rare occurrence that a server is unable to continue properly reading a directory with the provided cookie/cookieverf pair. The server should make every effort to avoid this condition since the application at the client may not be able to properly handle this type of failure. The use of the cookieverf will also protect the client from using READDIR cookie values that may be stale. For example, if the file system has been migrated, the server may or may not be able to use the same cookie values to service READDIR as the previous server + used. With the client providing the cookieverf, the server is able -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - used. With the client providing the cookieverf, the server is able 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. @@ -9013,29 +9378,26 @@ NFS4ERR_BADHANDLE NFS4ERR_BAD_COOKIE NFS4ERR_BADXDR NFS4ERR_DELAY NFS4ERR_FHEXPIRED NFS4ERR_INVAL NFS4ERR_IO NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE NFS4ERR_NOTDIR - NFS4ERR_NOTSUPP - NFS4ERR_NOT_SAME - NFS4ERR_READDIR_NOSPC NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_TOOSMALL -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.25. Operation 27: READLINK - Read Symbolic Link SYNOPSIS (cfh) -> linktext ARGUMENT /* CURRENT_FH: symlink */ @@ -9072,38 +9434,39 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.26. Operation 28: REMOVE - Remove Filesystem Object SYNOPSIS (cfh), filename -> change_info ARGUMENT struct REMOVE4args { @@ -9140,21 +9503,21 @@ 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. On success, the current filehandle retains its value. IMPLEMENTATION NFS versions 2 and 3 required a different operator RMDIR for -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -9170,56 +9533,57 @@ (disk space, directory entry, and so on) formerly associated with the object becoming immediately available. Thus, if a client needs to be able to continue to access a file after using REMOVE to remove it, the client should take steps to make sure that the file will still be accessible. The usual mechanism used is to RENAME the file from its old name to a new hidden name. If the server finds that the file is still open when the REMOVE arrives: - 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 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. However, until last CLOSE of the file, the server MAY - continue to allow access to the file via its filehandle. + directory entry. However, until last CLOSE of the file, the + server MAY continue to allow access to the file via its + filehandle. 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_NAMETOOLONG + NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE NFS4ERR_NOTDIR NFS4ERR_NOTEMPTY - NFS4ERR_NOTSUPP NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.27. Operation 29: RENAME - Rename Directory Entry SYNOPSIS (sfh), oldname, (cfh), newname -> source_change_info, target_change_info ARGUMENT @@ -9257,21 +9621,21 @@ 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 the IMPLEMENTATION subsection of the section "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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. @@ -9309,43 +9673,43 @@ ERRORS NFS4ERR_ACCESS NFS4ERR_BADCHAR NFS4ERR_BADHANDLE NFS4ERR_BADNAME NFS4ERR_BADXDR NFS4ERR_DELAY -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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_NOTSUPP NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_WRONGSEC + NFS4ERR_XDEV -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.28. Operation 30: RENEW - Renew a Lease SYNOPSIS clientid -> () ARGUMENT struct RENEW4args { @@ -9361,31 +9725,47 @@ 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. 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 error other than + NFS4ERR_CB_PATH_DOWN, even if the callback path is also down. + ERRORS + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADXDR + NFS4ERR_CB_PATH_DOWN NFS4ERR_EXPIRED - NFS4ERR_INVAL NFS4ERR_LEASE_MOVED + +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE_CLIENTID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.29. Operation 31: RESTOREFH - Restore Saved Filehandle SYNOPSIS (sfh) -> (cfh) ARGUMENT /* SAVED_FH: */ @@ -9394,22 +9774,22 @@ RESULT struct RESTOREFH4res { /* CURRENT_FH: value of saved fh */ nfsstat4 status; }; DESCRIPTION Set the current filehandle to the value in the saved filehandle. - If there is no saved filehandle then return an error - NFS4ERR_NOFILEHANDLE. + If there is no saved filehandle then return the error + NFS4ERR_RESTOREFH. 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. @@ -9420,30 +9800,29 @@ GETATTR attrbits (file attributes) RESTOREFH GETATTR attrbits (post-op dir attrs) ERRORS NFS4ERR_BADHANDLE NFS4ERR_FHEXPIRED NFS4ERR_MOVED -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - NFS4ERR_NOFILEHANDLE NFS4ERR_RESOURCE NFS4ERR_RESTOREFH NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_WRONGSEC -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.30. Operation 32: SAVEFH - Save Current Filehandle SYNOPSIS (cfh) -> (sfh) ARGUMENT /* CURRENT_FH: */ @@ -9469,21 +9848,21 @@ ERRORS NFS4ERR_BADHANDLE NFS4ERR_FHEXPIRED NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.31. Operation 33: SECINFO - Obtain Available Security SYNOPSIS (cfh), name -> { secinfo } ARGUMENT struct SECINFO4args { @@ -9520,24 +9899,24 @@ default: void; }; 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 methodology used for LOOKUP when evaluating the name. Therefore, - if the requestor does not have the appropriate access to LOOKUP the + 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 preferences, the most preferred being first in the array. The client is free to pick whatever security mechanism it both desires and supports, or to pick in the server's preference order the first one it supports. The array entries are represented by the secinfo4 structure. The field 'flavor' will contain a value of AUTH_NONE, @@ -9564,35 +9943,34 @@ 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 receive this error are: LINK, LOOKUP, OPEN, PUTFH, PUTPUBFH, PUTROOTFH, RESTOREFH, RENAME, and indirectly READDIR. LINK and RENAME will only receive this error if the security used for the - operation is inappropriate for saved filehandle. With the exception - of READDIR, With the exception of READDIR, these operations - represent the point at which the client can instantiate a - filehandle into the "current filehandle" at the server. The - filehandle is either provided by the client (PUTFH, PUTPUBFH, - PUTROOTFH) or generated as a result of a name to filehandle - translation (LOOKUP and OPEN). RESTOREFH is different because the - filehandle is a result of a previous SAVEFH. Even though the - filehandle, for RESTOREFH, might have previously passed the + operation is inappropriate for saved filehandle. With the + exception of READDIR, these operations represent the point at which + the client can instantiate a filehandle into the "current + filehandle" at the server. The filehandle is either provided by + the client (PUTFH, PUTPUBFH, PUTROOTFH) or generated as a result of + a name to filehandle translation (LOOKUP and OPEN). RESTOREFH is + different because the filehandle is a result of a previous SAVEFH. + Even though the filehandle, for RESTOREFH, might have previously + passed the server's inspection for a security match, the server -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - server's inspection for a security match, the server will check it - again on RESTOREFH to ensure that the security policy has not - changed. + will check it again on RESTOREFH to ensure that the security policy + has not changed. If the client wants to resolve an error return of NFS4ERR_WRONGSEC, the following will occur: o For LOOKUP and OPEN, the client will use SECINFO with the same current filehandle and name as provided in the original LOOKUP or OPEN to enumerate the available security triples. o For LINK, PUTFH, RENAME, and RESTOREFH, the client will use SECINFO and provide the parent directory filehandle and object @@ -9627,32 +10005,32 @@ ERRORS NFS4ERR_ACCESS NFS4ERR_BADCHAR NFS4ERR_BADHANDLE NFS4ERR_BADNAME NFS4ERR_BADXDR NFS4ERR_FHEXPIRED NFS4ERR_INVAL NFS4ERR_MOVED + NFS4ERR_NAMETOOLONG -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 - NFS4ERR_NAMETOOLONG NFS4ERR_NOENT NFS4ERR_NOFILEHANDLE NFS4ERR_NOTDIR NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.32. Operation 34: SETATTR - Set Attributes SYNOPSIS (cfh), stateid, attrmask, attr_vals -> attrsset ARGUMENT struct SETATTR4args { @@ -9689,29 +10067,29 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 requestor has privilege to do so. If the + 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. The file size attribute is used to request changes to the size of a file. A value of 0 (zero) causes the file to be truncated, a value less than the current size of the file causes data from new size to the end of the file to be discarded, and a size greater than the current size of the file causes logically zeroed data bytes to be added to the end of the file. Servers are free to implement this @@ -9744,63 +10122,63 @@ means whereby a client may specify a request that emulates the functionality of the SETATTR guard mechanism of NFS version 3. Since the function of the guard mechanism is to avoid changes to the file attributes based on stale information, delays between checking of the guard condition and the setting of the attributes have the potential to compromise this function, as would the corresponding delay in the NFS version 4 emulation. Therefore, NFS version 4 servers should take care to avoid such delays, to the degree possible, when executing such a request. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 If the server does not support an attribute as requested by the client, the server should return NFS4ERR_ATTRNOTSUPP. - A mask of the attibutes actually set is returned by SETATTR in all + 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. 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_NOTSUPP NFS4ERR_OLD_STATEID NFS4ERR_OPENMODE NFS4ERR_PERM NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_STALE_STATEID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.33. Operation 35: SETCLIENTID - Negotiate Clientid SYNOPSIS client, callback, callback_ident -> clientid, setclientid_confirm ARGUMENT struct SETCLIENTID4args { @@ -9820,39 +10198,39 @@ case NFS4_OK: SETCLIENTID4resok resok4; case NFS4ERR_CLID_INUSE: clientaddr4 client_using; default: void; }; DESCRIPTION - The client uses SETCLIENTID operation to notify the server of its - intention to use a particular client identifier, callback, and + 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 short hand 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. The reason why two verifiers are necessary is that it is possible to use SETCLIENTID and SETCLIENTID_CONFIRM to modify the callback and callback_ident information but not the short hand clientid. In that event, the setclientid_confirm value is effectively the only verifier. The callback information provided in this operation will be used if the client is provided an open delegation at a future point. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 use leverage the callback_ident eliminate the need for more than one callback RPC program number while still being able to determine which server is initiating the callback. IMPLEMENTATION @@ -9890,21 +10268,21 @@ o It first looks up the request in the DRC. If there is a hit, it returns the result cached in the DRC. The server does NOT remove client state (locks, shares, delegations) nor does it modify any recorded callback and callback_ident information for client { x }. For any DRC miss, the server takes the client id string x, and searches for client records for x that the server may have recorded from previous SETCLIENTID calls. For any confirmed -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 record with the same id string x, if the recorded principal does not match that of SETCLIENTID call, then the server returns a NFS4ERR_CLID_INUSE error. For brevity of discussion, the remaining description of the processing assumes that there was a DRC miss, and that where the server has previously recorded a confirmed record for client x, the aforementioned principal check has successfully passed. @@ -9942,21 +10320,21 @@ SETCLIENTID_CONFIRM { d, t }. The server does NOT remove client (lock/share/delegation) state for x. o The server has previously recorded a confirmed { u, x, c, l, s } record such that v != u, l may or may not equal k, and recorded an unconfirmed { w, x, d, m, t } record such that c != d, t != s, m may or may not equal k, m may or may not equal l, and k may or -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 may not equal l. Whether w == v or w != v makes no difference. The server simply removes the unconfirmed { w, x, d, m, t } record and replaces it with an unconfirmed { v, x, e, k, r } record, such that e != d, e != c, r != t, r != s. The server returns { e, r }. The server awaits confirmation of { e, k } via SETCLIENTID_CONFIRM { e, r }. @@ -9982,21 +10360,21 @@ unlikely to ever be regenerated. ERRORS NFS4ERR_BADXDR NFS4ERR_CLID_INUSE NFS4ERR_INVAL NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.34. Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid SYNOPSIS clientid, verifier -> - ARGUMENT struct SETCLIENTID_CONFIRM4args { @@ -10032,34 +10410,34 @@ includes record locks, share reservations, and where the server does not support the CLAIM_DELEGATE_PREV claim type, delegations. If the server supports CLAIM_DELEGATE_PREV, then SETCLIENTID_CONFIRM MUST NOT remove delegations for this client; relevant leased client state would then just include record locks and share reservations. o The client's re-use of an old, previously confirmed, shorthand client identifier, a new callback value, and a new callback_ident -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 value. The client's use of SETCLIENTID_CONFIRM in this case MUST NOT result in the removal of any previous leased state (locks, share reservations, and delegations) We use the same notation and definitions for v, x, c, k, s, and unconfirmed and confirmed client records as introduced in the description of the SETCLIENTID operation. The arguments to SETCLIENTID_CONFIRM are indicated by the notation { c, s }, where c is a value of type clientid4, and s is a value of type verifier4 corresponding to the setclientid_confirm field. - As with SETCLIENTID, SETCLIENTID_CONFIRM is a nonidempotent + As with SETCLIENTID, SETCLIENTID_CONFIRM is a non-idempotent operation, and we assume that the server is implementing the duplicate request cache (DRC). When the server gets a SETCLIENTID_CONFIRM { c, s } request, it processes it in the following manner. o It first looks up the request in the DRC. If there is a hit, it returns the result cached in the DRC. The server does not remove any relevant leased client state nor does it modify any recorded callback and callback_ident information for client { x } as @@ -10087,21 +10465,21 @@ has recorded a confirmed { v, x, c, *, s }. If the principals of the record and of SETCLIENTID_CONFIRM do not match, the server returns NFS4ERR_CLID_INUSE without removing any relevant leased client state and without changing recorded callback and callback_ident values for client { x }. If the principals match, then what has likely happened is that the client never got the response from the SETCLIENTID_CONFIRM, and the DRC entry has been purged. Whatever the scenario, since -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 the principals match, as well as { c, s } matching a confirmed record, the server leaves client x's relevant leased client state intact, leaves its callback and callback_ident values unmodified, and returns NFS4_OK. o The server has not recorded a confirmed { *, *, c, *, * }, and has recorded an unconfirmed { *, x, c, k, s }. Even if this is a retry from client, nonetheless the client's first SETCLIENTID_CONFIRM attempt was not received by the server. @@ -10113,72 +10491,72 @@ Otherwise, the server records a confirmed { *, x, c, k, s }. If there is also a confirmed { *, x, d, *, t }, the server MUST remove the client x's relevant leased client state, and overwrite the callback state with k. The confirmed record { *, x, d, *, t } is removed. Server returns NFS4_OK. o The server has no record of a confirmed or unconfirmed { *, *, c, - *, s }. Return NFS4ERR_STALE_CLIENTID. The server does not - remove any relevant leased client state, nor does it modify any - recorded callback and callback_ident information for any client. + *, s }. The server returns NFS4ERR_STALE_CLIENTID. The server + does not remove any relevant leased client state, nor does it + modify any recorded callback and callback_ident information for + any client. The server needs to cache unconfirmed { v, x, c, k, s } client records and await for some time their confirmation. As should be clear from the record processing discussions for SETCLIENTID and SETCLIENTID_CONFIRM, there are cases where the server does not deterministically remove unconfirmed client records. To avoid running out of resources, the server is not required to hold unconfirmed records indefinitely. One strategy the server might use is to set a limit on how many unconfirmed client records it will maintain, and then when the limit would be exceeded, remove the oldest record. Another strategy might be to remove an unconfirmed record when some amount of time has elapsed. The choice of the amount of time is fairly arbitrary but it is surely no higher than the server's lease time period. Consider that leases need to be renewed before the lease time expires via an operation from the client. If the client cannot issue a SETCLIENTID_CONFIRM - after a SETCLIENTID before a perod of time equal to that of a lease - expires, then the client is unlikely to be able maintain state on - the server during steady state operation. + after a SETCLIENTID before a period of time equal to that of a + lease expires, then the client is unlikely to be able maintain + state on the server during steady state operation. If the client does send a SETCLIENTID_CONFIRM for an unconfirmed record that the server has already deleted, the client will get NFS4ERR_STALE_CLIENTID back. If so, the client should then start over, and send SETCLIENTID to reestablish an unconfirmed client - record and get back an unconfirmed clientid and setclientid_confirm -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + record and get back an unconfirmed clientid and setclientid_confirm verifier. The client should then send the SETCLIENTID_CONFIRM to 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 tpe of the OPEN operation) its delegations before removing + claim type of the OPEN operation) its delegations before removing unreclaimed delegations. ERRORS NFS4ERR_BADXDR NFS4ERR_CLID_INUSE - NFS4ERR_INVAL NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE_CLIENTID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.35. Operation 37: VERIFY - Verify Same Attributes SYNOPSIS (cfh), fattr -> - ARGUMENT struct VERIFY4args { @@ -10214,50 +10592,48 @@ VERIFY (filehandle == fh) PUTFH (directory filehandle) REMOVE (file name) This sequence does not prevent a second client from removing and creating a new file in the middle of this sequence but it does help avoid the unintended result. 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_NOTSUPP is returned to the + filesystem object, the error NFS4ERR_ATTRNOTSUPP is returned to the -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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. If both of these conditions apply, the server is free to - return either error. + time_modify_set) is specified, the error NFS4ERR_INVAL is returned + to the client. ERRORS NFS4ERR_ACCESS NFS4ERR_ATTRNOTSUPP NFS4ERR_BADCHAR NFS4ERR_BADHANDLE NFS4ERR_BADXDR NFS4ERR_DELAY NFS4ERR_FHEXPIRED NFS4ERR_INVAL NFS4ERR_MOVED NFS4ERR_NOFILEHANDLE - NFS4ERR_NOTSUPP NFS4ERR_NOT_SAME NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT NFS4ERR_STALE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.36. Operation 38: WRITE - Write to File SYNOPSIS (cfh), stateid, offset, stable, data -> count, committed, writeverf ARGUMENT enum stable_how4 { @@ -10295,21 +10671,21 @@ 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. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Part of the write request is a specification of how the write is to be performed. The client specifies with the stable parameter the method of how the data is to be processed by the server. If stable is FILE_SYNC4, the server must commit the data written plus all filesystem metadata to stable storage before returning results. This corresponds to the NFS version 2 protocol semantics. Any other behavior constitutes a protocol violation. If stable is DATA_SYNC4, then the server must commit all of the data to stable storage and enough of the metadata to retrieve the data before @@ -10349,21 +10725,21 @@ FILE_SYNC4, DATA_SYNC4, or UNSTABLE4. The final portion of the result is the write verifier. The write verifier is a cookie that the client can use to determine whether the server has changed instance (boot) state between a call to WRITE and a subsequent call to either WRITE or COMMIT. This cookie must be consistent during a single instance of the NFS version 4 protocol service and must be unique between instances of the NFS version 4 protocol server, where uncommitted data may be lost. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 If a client writes data to the server with the stable argument set to UNSTABLE4 and the reply yields a committed response of DATA_SYNC4 or UNSTABLE4, the client will follow up some time in the future with a COMMIT operation to synchronize outstanding asynchronous data and metadata with the server's stable storage, barring client error. It is possible that due to client crash or other error that a subsequent COMMIT will not be received by the server. @@ -10401,21 +10777,21 @@ This definition does not address failure of the stable storage module itself. The verifier is defined to allow a client to detect different instances of an NFS version 4 protocol server over which cached, uncommitted data may be lost. In the most likely case, the verifier allows the client to detect server reboots. This information is required so that the client can safely determine whether the server -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 could have lost cached data. If the server fails unexpectedly and the client has uncommitted data from previous WRITE requests (done with the stable argument set to UNSTABLE4 and in which the result committed was returned as UNSTABLE4 as well) it may not have flushed cached data to stable storage. The burden of recovery is on the client and the client will need to retransmit the data to the server. A suggested verifier would be to use the time that the server was @@ -10431,48 +10807,49 @@ effectiveness of the cache by discarding cached data that has already been committed on the server. Some implementations may return NFS4ERR_NOSPC instead of NFS4ERR_DQUOT when a user's quota is exceeded. In the case that the current filehandle is a directory, the server will return NFS4ERR_ISDIR. If the current filehandle is not a regular file or a directory, the server will return NFS4ERR_INVAL. If mandatory file locking is on for the file, and corresponding - record of the to be written file is read or write locked by an + record of the data to be written file is read or write locked by an owner that is not associated with the stateid, the server will return NFS4ERR_LOCKED. If so, the client must check if the owner corresponding to the stateid used with the WRITE operation has a conflicting read lock that overlaps with the region that was to be written. If the stateid's owner has no conflicting read lock, then the client should try to get the appropriate write record lock via the LOCK operation before re-attempting the WRITE. When the WRITE completes, the client should release the record lock via LOCKU. If the stateid's owner had a conflicting read lock, then the client has no choice but to return an error to the application that 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 pointless to try a LOCK operation to + upgrade capability, then it is pointless to try a LOCK operation to upgrade. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 @@ -10485,21 +10862,21 @@ NFS4ERR_NOSPC NFS4ERR_NXIO NFS4ERR_OLD_STATEID NFS4ERR_OPENMODE NFS4ERR_RESOURCE NFS4ERR_ROFS NFS4ERR_SERVERFAULT NFS4ERR_STALE NFS4ERR_STALE_STATEID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.37. Operation 39: RELEASE_LOCKOWNER - Release Lockowner State SYNOPSIS lockowner -> () ARGUMENT struct RELEASE_LOCKOWNER4args { @@ -10527,39 +10904,39 @@ 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. ERRORS + NFS4ERR_ADMIN_REVOKED NFS4ERR_BADXDR NFS4ERR_EXPIRED - NFS4ERR_GRACE NFS4ERR_LEASE_MOVED NFS4ERR_LOCKS_HELD NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_STALE_CLIENTID -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 14.2.38. Operation 10044: ILLEGAL - Illegal operation SYNOPSIS - + -> () ARGUMENT void; RESULT struct ILLEGAL4res { nfsstat4 status; }; @@ -10579,21 +10956,21 @@ 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. ERRORS NFS4ERR_OP_ILLEGAL -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 15. 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 @@ -10614,21 +10991,21 @@ 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. ERRORS None. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 15.2. Procedure 1: CB_COMPOUND - Compound Operations SYNOPSIS compoundargs -> compoundres ARGUMENT enum nfs_cb_opnum4 { @@ -10666,37 +11043,37 @@ 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 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 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 the section "Procedure - 1: COMPOUND - Compound Operatoins". + 1: COMPOUND - Compound Operations". 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. IMPLEMENTATION @@ -10706,30 +11083,32 @@ 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. ERRORS NFS4ERR_BADHANDLE NFS4ERR_BAD_STATEID + NFS4ERR_BADXDR NFS4ERR_OP_ILLEGAL NFS4ERR_RESOURCE + NFS4ERR_SERVERFAULT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 15.2.1. Operation 3: CB_GETATTR - Get Attributes SYNOPSIS - fh, attrbits -> attrbits, attrvals + fh, attr_request -> attrmask, attr_vals ARGUMENT struct CB_GETATTR4args { nfs_fh4 fh; bitmap4 attr_request; }; RESULT @@ -10751,40 +11130,40 @@ The attributes size and change are the only ones guaranteed to be serviced by the client. See the section "Handling of CB_GETATTR" 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. IMPLEMENTATION - The client returns attrbits and the associated attribute values - only for attributes that it may change (change, time_modify, size). + 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). ERRORS - NFS4ERR_BADHANDLE - -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + NFS4ERR_BADHANDLE NFS4ERR_BADXDR NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 15.2.2. Operation 4: CB_RECALL - Recall an Open Delegation SYNOPSIS - stateid, truncate, fh -> status + stateid, truncate, fh -> () ARGUMENT struct CB_RECALL4args { stateid4 stateid; bool truncate; nfs_fh4 fh; }; RESULT @@ -10814,34 +11193,34 @@ 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. ERRORS NFS4ERR_BADHANDLE -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_BAD_STATEID NFS4ERR_BADXDR NFS4ERR_RESOURCE NFS4ERR_SERVERFAULT -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 15.2.3. Operation 10044: CB_ILLEGAL - Illegal Callback Operation SYNOPSIS - + -> () ARGUMENT void; RESULT struct CB_ILLEGAL4res { nfsstat4 status; }; @@ -10863,21 +11242,21 @@ 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. ERRORS NFS4ERR_OP_ILLEGAL -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 16. Security Considerations The major security feature to consider is the authentication of the user making the request of NFS service. Consideration should also be given to the integrity and privacy of this NFS request. These specific issues are discussed as part of the section on "RPC and Security Flavor". For reasons of reduced administration overhead, better performance @@ -10909,21 +11288,21 @@ 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 the section "Client ID" for further discussion. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 17. IANA Considerations 17.1. 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; the application developer or system vendor is allowed to define the @@ -10934,37 +11313,37 @@ assignment and associated semantics for attributes via an Informational RFC. This will provide for interoperability where common interests exist. 17.2. 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. There should be a registry at IANA for netids and the corresponding universal address format corresponding to the native address format - for the transport represent by a a netid. + for the transport represented by a netid. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 18. RPC definition file /* * Copyright (C) The Internet Society (1998,1999,2000,2001,2002). * All Rights Reserved. */ /* * nfs4_prot.x * */ - %#pragma ident "@(#)nfs4_prot.x 1.117" + %#pragma ident "@(#)nfs4_prot.x 1.119" /* * Basic typedefs for RFC 1832 data type definitions */ typedef int int32_t; typedef unsigned int uint32_t; typedef hyper int64_t; typedef unsigned hyper uint64_t; /* @@ -10991,44 +11370,44 @@ /* * Error status */ enum nfsstat4 { NFS4_OK = 0, /* everything is okay */ NFS4ERR_PERM = 1, /* caller not privileged */ NFS4ERR_NOENT = 2, /* no such file/directory */ NFS4ERR_IO = 5, /* hard I/O error */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_NXIO = 6, /* no such device */ NFS4ERR_ACCESS = 13, /* access denied */ NFS4ERR_EXIST = 17, /* file already exists */ NFS4ERR_XDEV = 18, /* different filesystems */ - NFS4ERR_NODEV = 19, /* no such device */ + /* Unused/reserved 19 */ NFS4ERR_NOTDIR = 20, /* should be a directory */ NFS4ERR_ISDIR = 21, /* should not be directory */ NFS4ERR_INVAL = 22, /* invalid argument */ NFS4ERR_FBIG = 27, /* file exceeds server max */ NFS4ERR_NOSPC = 28, /* no space on filesystem */ NFS4ERR_ROFS = 30, /* read-only filesystem */ NFS4ERR_MLINK = 31, /* too many hard links */ NFS4ERR_NAMETOOLONG = 63, /* name exceeds server max */ NFS4ERR_NOTEMPTY = 66, /* directory not empty */ NFS4ERR_DQUOT = 69, /* hard quota limit reached*/ NFS4ERR_STALE = 70, /* file no longer exists */ NFS4ERR_BADHANDLE = 10001,/* Illegal filehandle */ NFS4ERR_BAD_COOKIE = 10003,/* READDIR cookie is stale */ NFS4ERR_NOTSUPP = 10004,/* operation not supported */ - NFS4ERR_TOOSMALL = 10005,/* buffer too small */ + NFS4ERR_TOOSMALL = 10005,/* response limit exceeded */ NFS4ERR_SERVERFAULT = 10006,/* undefined server error */ - NFS4ERR_BADTYPE = 10007,/* type invalide for CREATE*/ + NFS4ERR_BADTYPE = 10007,/* type invalid for CREATE */ NFS4ERR_DELAY = 10008,/* file "busy" - retry */ NFS4ERR_SAME = 10009,/* nverify says attrs same */ NFS4ERR_DENIED = 10010,/* lock unavailable */ NFS4ERR_EXPIRED = 10011,/* lock lease expired */ NFS4ERR_LOCKED = 10012,/* I/O failed due to lock */ NFS4ERR_GRACE = 10013,/* in grace period */ NFS4ERR_FHEXPIRED = 10014,/* filehandle expired */ NFS4ERR_SHARE_DENIED = 10015,/* share reserve denied */ NFS4ERR_WRONGSEC = 10016,/* wrong security flavor */ NFS4ERR_CLID_INUSE = 10017,/* clientid in use */ @@ -11037,40 +11416,42 @@ NFS4ERR_NOFILEHANDLE = 10020,/* current FH is not set */ NFS4ERR_MINOR_VERS_MISMATCH = 10021,/* minor vers not supp */ NFS4ERR_STALE_CLIENTID = 10022,/* server has rebooted */ NFS4ERR_STALE_STATEID = 10023,/* server has rebooted */ NFS4ERR_OLD_STATEID = 10024,/* state is out of sync */ NFS4ERR_BAD_STATEID = 10025,/* incorrect stateid */ NFS4ERR_BAD_SEQID = 10026,/* request is out of seq. */ NFS4ERR_NOT_SAME = 10027,/* verify - attrs not same */ NFS4ERR_LOCK_RANGE = 10028,/* lock range not supported*/ NFS4ERR_SYMLINK = 10029,/* should be file/directory*/ - NFS4ERR_READDIR_NOSPC = 10030,/* response limit exceeded */ + NFS4ERR_RESTOREFH = 10030,/* no saved filehandle */ NFS4ERR_LEASE_MOVED = 10031,/* some filesystem moved */ NFS4ERR_ATTRNOTSUPP = 10032,/* recommended attr not sup*/ NFS4ERR_NO_GRACE = 10033,/* reclaim outside of grace*/ NFS4ERR_RECLAIM_BAD = 10034,/* reclaim error at server */ NFS4ERR_RECLAIM_CONFLICT = 10035,/* conflict on reclaim */ NFS4ERR_BADXDR = 10036,/* XDR decode failed */ - NFS4ERR_LOCKS_HELD = 10037,/* file lcoks held at CLOSE*/ + NFS4ERR_LOCKS_HELD = 10037,/* file locks held at CLOSE*/ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 NFS4ERR_OPENMODE = 10038,/* conflict in OPEN and I/O*/ NFS4ERR_BADOWNER = 10039,/* owner translation bad */ NFS4ERR_BADCHAR = 10040,/* utf-8 char not supported*/ NFS4ERR_BADNAME = 10041,/* name not supported */ NFS4ERR_BAD_RANGE = 10042,/* lock range not supported*/ NFS4ERR_LOCK_NOTSUPP = 10043,/* no atomic up/downgrade */ NFS4ERR_OP_ILLEGAL = 10044,/* undefined operation */ NFS4ERR_DEADLOCK = 10045,/* file locking deadlock */ - NFS4ERR_FILE_OPEN = 10046 /* open file blocks op. */ + NFS4ERR_FILE_OPEN = 10046,/* open file blocks op. */ + NFS4ERR_ADMIN_REVOKED = 10047,/* lockowner state revoked */ + NFS4ERR_CB_PATH_DOWN = 10048 /* callback path down */ }; /* * Basic data types */ typedef uint32_t bitmap4<>; typedef uint64_t offset4; typedef uint32_t count4; typedef uint64_t length4; typedef uint64_t clientid4; @@ -11098,23 +11479,24 @@ enum time_how4 { SET_TO_SERVER_TIME4 = 0, SET_TO_CLIENT_TIME4 = 1 }; union settime4 switch (time_how4 set_it) { case SET_TO_CLIENT_TIME4: nfstime4 time; default: void; - }; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + + }; /* * File access handle */ typedef opaque nfs_fh4; /* * File attribute definitions */ @@ -11150,25 +11532,25 @@ const ACL4_SUPPORT_ALLOW_ACL = 0x00000001; const ACL4_SUPPORT_DENY_ACL = 0x00000002; const ACL4_SUPPORT_AUDIT_ACL = 0x00000004; const ACL4_SUPPORT_ALARM_ACL = 0x00000008; typedef uint32_t acetype4; /* * acetype4 values, others can be added as needed. */ - const ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000; - const ACE4_ACCESS_DENIED_ACE_TYPE = 0x00000001; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + 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; /* * ACE flag */ typedef uint32_t aceflag4; /* * ACE flag values @@ -11203,25 +11585,25 @@ 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; /* * ACE4_GENERIC_READ -- defined as combination of - * ACE4_READ_ACL | - * ACE4_READ_DATA | -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + * ACE4_READ_ACL | + * ACE4_READ_DATA | * ACE4_READ_ATTRIBUTES | * ACE4_SYNCHRONIZE */ const ACE4_GENERIC_READ = 0x00120081; /* * ACE4_GENERIC_WRITE -- defined as combination of * ACE4_READ_ACL | * ACE4_WRITE_DATA | @@ -11256,25 +11638,25 @@ */ 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 */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + const MODE4_ROTH = 0x004; /* read permission: other */ + const MODE4_WOTH = 0x002; /* write permission: other */ const MODE4_XOTH = 0x001; /* execute permission: other */ /* * Special data/attribute associated with * file types NF4BLK and NF4CHR. */ struct specdata4 { uint32_t specdata1; /* major device number */ uint32_t specdata2; /* minor device number */ }; @@ -11310,25 +11692,25 @@ typedef bool fattr4_chown_restricted; typedef uint64_t fattr4_fileid; typedef uint64_t fattr4_files_avail; typedef nfs_fh4 fattr4_filehandle; typedef uint64_t fattr4_files_free; typedef uint64_t fattr4_files_total; typedef fs_locations4 fattr4_fs_locations; typedef bool fattr4_hidden; typedef bool fattr4_homogeneous; typedef uint64_t fattr4_maxfilesize; - typedef uint32_t fattr4_maxlink; - typedef uint32_t fattr4_maxname; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + typedef uint32_t fattr4_maxlink; + typedef uint32_t fattr4_maxname; typedef uint64_t fattr4_maxread; typedef uint64_t fattr4_maxwrite; typedef utf8string fattr4_mimetype; typedef mode4 fattr4_mode; typedef uint64_t fattr4_mounted_on_fileid; typedef bool fattr4_no_trunc; typedef uint32_t fattr4_numlinks; typedef utf8string fattr4_owner; typedef utf8string fattr4_owner_group; typedef uint64_t fattr4_quota_avail_hard; @@ -11364,25 +11746,25 @@ const FATTR4_UNIQUE_HANDLES = 9; const FATTR4_LEASE_TIME = 10; const FATTR4_RDATTR_ERROR = 11; const FATTR4_FILEHANDLE = 19; /* * Recommended Attributes */ const FATTR4_ACL = 12; const FATTR4_ACLSUPPORT = 13; - const FATTR4_ARCHIVE = 14; - const FATTR4_CANSETTIME = 15; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + const FATTR4_ARCHIVE = 14; + const FATTR4_CANSETTIME = 15; const FATTR4_CASE_INSENSITIVE = 16; const FATTR4_CASE_PRESERVING = 17; const FATTR4_CHOWN_RESTRICTED = 18; const FATTR4_FILEID = 20; const FATTR4_FILES_AVAIL = 21; const FATTR4_FILES_FREE = 22; const FATTR4_FILES_TOTAL = 23; const FATTR4_FS_LOCATIONS = 24; const FATTR4_HIDDEN = 25; const FATTR4_HOMOGENEOUS = 26; @@ -11419,25 +11801,24 @@ typedef opaque attrlist4<>; /* * File attribute container */ struct fattr4 { bitmap4 attrmask; attrlist4 attr_vals; }; +Draft Specification NFS version 4 Protocol September 2002 + /* * Change info for the client - -Draft Specification NFS version 4 Protocol August 2002 - */ struct change_info4 { bool atomic; changeid4 before; changeid4 after; }; struct clientaddr4 { /* see struct rpcb in RFC 1833 */ string r_netid<>; /* network id */ @@ -11474,25 +11855,25 @@ }; struct lock_owner4 { clientid4 clientid; opaque owner; }; enum nfs_lock_type4 { READ_LT = 1, WRITE_LT = 2, - READW_LT = 3, /* blocking read */ - WRITEW_LT = 4 /* blocking write */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + READW_LT = 3, /* blocking read */ + WRITEW_LT = 4 /* blocking write */ }; /* * ACCESS: Check access permission */ const ACCESS4_READ = 0x00000001; const ACCESS4_LOOKUP = 0x00000002; const ACCESS4_MODIFY = 0x00000004; const ACCESS4_EXTEND = 0x00000008; const ACCESS4_DELETE = 0x00000010; @@ -11529,25 +11910,25 @@ stateid4 open_stateid; default: void; }; /* * COMMIT: Commit cached data on server to stable storage */ struct COMMIT4args { /* CURRENT_FH: file */ - offset4 offset; - count4 count; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + offset4 offset; + count4 count; }; struct COMMIT4resok { verifier4 writeverf; }; union COMMIT4res switch (nfsstat4 status) { case NFS4_OK: COMMIT4resok resok4; default: @@ -11583,25 +11964,24 @@ bitmap4 attrset; /* attributes set */ }; union CREATE4res switch (nfsstat4 status) { case NFS4_OK: CREATE4resok resok4; default: void; }; +Draft Specification NFS version 4 Protocol September 2002 + /* * DELEGPURGE: Purge Delegations Awaiting Recovery - -Draft Specification NFS version 4 Protocol August 2002 - */ struct DELEGPURGE4args { clientid4 clientid; }; struct DELEGPURGE4res { nfsstat4 status; }; /* @@ -11638,25 +12018,25 @@ /* * GETFH: Get current filehandle */ struct GETFH4resok { nfs_fh4 object; }; union GETFH4res switch (nfsstat4 status) { case NFS4_OK: GETFH4resok resok4; - default: - void; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + default: + void; }; /* * LINK: Create link to an object */ struct LINK4args { /* SAVED_FH: source object */ /* CURRENT_FH: target directory */ component4 newname; }; @@ -11693,25 +12073,25 @@ union locker4 switch (bool new_lock_owner) { case TRUE: open_to_lock_owner4 open_owner; case FALSE: exist_lock_owner4 lock_owner; }; /* * LOCK/LOCKT/LOCKU: Record lock management */ - struct LOCK4args { - /* CURRENT_FH: file */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + struct LOCK4args { + /* CURRENT_FH: file */ nfs_lock_type4 locktype; bool reclaim; offset4 offset; length4 length; locker4 locker; }; struct LOCK4denied { offset4 offset; length4 length; @@ -11748,25 +12128,26 @@ default: void; }; struct LOCKU4args { /* CURRENT_FH: file */ nfs_lock_type4 locktype; seqid4 seqid; stateid4 lock_stateid; offset4 offset; + +Draft Specification NFS version 4 Protocol September 2002 + length4 length; }; -Draft Specification NFS version 4 Protocol August 2002 - union LOCKU4res switch (nfsstat4 status) { case NFS4_OK: stateid4 lock_stateid; default: void; }; /* * LOOKUP: Lookup filename */ @@ -11802,26 +12183,25 @@ /* * Various definitions for OPEN */ enum createmode4 { UNCHECKED4 = 0, GUARDED4 = 1, EXCLUSIVE4 = 2 }; +Draft Specification NFS version 4 Protocol September 2002 + union createhow4 switch (createmode4 mode) { case UNCHECKED4: case GUARDED4: - -Draft Specification NFS version 4 Protocol August 2002 - fattr4 createattrs; case EXCLUSIVE4: verifier4 createverf; }; enum opentype4 { OPEN4_NOCREATE = 0, OPEN4_CREATE = 1 }; @@ -11858,25 +12238,24 @@ */ 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; +Draft Specification NFS version 4 Protocol September 2002 + enum open_delegation_type4 { OPEN_DELEGATE_NONE = 0, - -Draft Specification NFS version 4 Protocol August 2002 - OPEN_DELEGATE_READ = 1, OPEN_DELEGATE_WRITE = 2 }; enum open_claim_type4 { CLAIM_NULL = 0, CLAIM_PREVIOUS = 1, CLAIM_DELEGATE_CUR = 2, CLAIM_DELEGATE_PREV = 3 }; @@ -11913,25 +12292,25 @@ /* Right to file based on a delegation granted to a previous boot * instance of the client. File is specified by name. */ case CLAIM_DELEGATE_PREV: /* CURRENT_FH: directory */ component4 file_delegate_prev; }; /* - * OPEN: Open a file, potentially receiving an open delegation - */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + * OPEN: Open a file, potentially receiving an open delegation + */ struct OPEN4args { seqid4 seqid; uint32_t share_access; uint32_t share_deny; open_owner4 owner; openflag4 openhow; open_claim4 claim; }; struct open_read_delegation4 { @@ -11968,25 +12347,25 @@ case OPEN_DELEGATE_NONE: void; case OPEN_DELEGATE_READ: open_read_delegation4 read; case OPEN_DELEGATE_WRITE: open_write_delegation4 write; }; /* * Result flags - */ - /* Client must confirm open */ -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + */ + /* Client must confirm open */ const OPEN4_RESULT_CONFIRM = 0x00000002; /* Type of file locking behavior at the server */ const OPEN4_RESULT_LOCKTYPE_POSIX = 0x00000004; struct OPEN4resok { stateid4 stateid; /* Stateid for open */ change_info4 cinfo; /* Directory Change Info */ uint32_t rflags; /* Result flags */ bitmap4 attrset; /* attribute set for create*/ open_delegation4 delegation; /* Info on any open @@ -12023,25 +12402,25 @@ seqid4 seqid; }; struct OPEN_CONFIRM4resok { stateid4 open_stateid; }; union OPEN_CONFIRM4res switch (nfsstat4 status) { case NFS4_OK: OPEN_CONFIRM4resok resok4; - default: - void; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + default: + void; }; /* * OPEN_DOWNGRADE: downgrade the access/deny for a file */ struct OPEN_DOWNGRADE4args { /* CURRENT_FH: opened file */ stateid4 open_stateid; seqid4 seqid; uint32_t share_access; @@ -12078,23 +12457,24 @@ /* CURRENT_FH: public fh */ nfsstat4 status; }; /* * PUTROOTFH: Set root filehandle */ struct PUTROOTFH4res { /* CURRENT_FH: root fh */ nfsstat4 status; - }; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 + + }; /* * READ: Read from file */ struct READ4args { /* CURRENT_FH: file */ stateid4 stateid; offset4 offset; count4 count; }; @@ -12133,21 +12513,21 @@ struct dirlist4 { entry4 *entries; bool eof; }; struct READDIR4resok { verifier4 cookieverf; dirlist4 reply; }; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 union READDIR4res switch (nfsstat4 status) { case NFS4_OK: READDIR4resok resok4; default: void; }; /* * READLINK: Read symbolic link @@ -12187,21 +12567,21 @@ */ struct RENAME4args { /* SAVED_FH: source directory */ component4 oldname; /* CURRENT_FH: target directory */ component4 newname; }; struct RENAME4resok { -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 change_info4 source_cinfo; change_info4 target_cinfo; }; union RENAME4res switch (nfsstat4 status) { case NFS4_OK: RENAME4resok resok4; default: void; @@ -12242,21 +12622,21 @@ /* CURRENT_FH: directory */ component4 name; }; /* * From RFC 2203 */ enum rpc_gss_svc_t { RPC_GSS_SVC_NONE = 1, -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 RPC_GSS_SVC_INTEGRITY = 2, RPC_GSS_SVC_PRIVACY = 3 }; struct rpcsec_gss_info { sec_oid4 oid; qop4 qop; rpc_gss_svc_t service; }; @@ -12297,21 +12677,21 @@ */ struct SETCLIENTID4args { nfs_client_id4 client; cb_client4 callback; uint32_t callback_ident; }; struct SETCLIENTID4resok { clientid4 clientid; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 verifier4 setclientid_confirm; }; union SETCLIENTID4res switch (nfsstat4 status) { case NFS4_OK: SETCLIENTID4resok resok4; case NFS4ERR_CLID_INUSE: clientaddr4 client_using; default: @@ -12352,21 +12732,21 @@ /* CURRENT_FH: file */ stateid4 stateid; offset4 offset; stable_how4 stable; opaque data<>; }; struct WRITE4resok { count4 count; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 stable_how4 committed; verifier4 writeverf; }; union WRITE4res switch (nfsstat4 status) { case NFS4_OK: WRITE4resok resok4; default: void; @@ -12407,21 +12787,21 @@ OP_LOCK = 12, OP_LOCKT = 13, OP_LOCKU = 14, OP_LOOKUP = 15, OP_LOOKUPP = 16, OP_NVERIFY = 17, OP_OPEN = 18, OP_OPENATTR = 19, OP_OPEN_CONFIRM = 20, -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 OP_OPEN_DOWNGRADE = 21, OP_PUTFH = 22, OP_PUTPUBFH = 23, OP_PUTROOTFH = 24, OP_READ = 25, OP_READDIR = 26, OP_READLINK = 27, OP_REMOVE = 28, OP_RENAME = 29, @@ -12462,21 +12842,21 @@ case OP_PUTPUBFH: void; case OP_PUTROOTFH: void; case OP_READ: READ4args opread; case OP_READDIR: READDIR4args opreaddir; case OP_READLINK: void; case OP_REMOVE: REMOVE4args opremove; case OP_RENAME: RENAME4args oprename; case OP_RENEW: RENEW4args oprenew; case OP_RESTOREFH: void; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 case OP_SAVEFH: void; case OP_SECINFO: SECINFO4args opsecinfo; case OP_SETATTR: SETATTR4args opsetattr; case OP_SETCLIENTID: SETCLIENTID4args opsetclientid; case OP_SETCLIENTID_CONFIRM: SETCLIENTID_CONFIRM4args opsetclientid_confirm; case OP_VERIFY: VERIFY4args opverify; case OP_WRITE: WRITE4args opwrite; case OP_RELEASE_LOCKOWNER: RELEASE_LOCKOWNER4args @@ -12517,21 +12897,21 @@ case OP_SAVEFH: SAVEFH4res opsavefh; case OP_SECINFO: SECINFO4res opsecinfo; case OP_SETATTR: SETATTR4res opsetattr; case OP_SETCLIENTID: SETCLIENTID4res opsetclientid; case OP_SETCLIENTID_CONFIRM: SETCLIENTID_CONFIRM4res opsetclientid_confirm; case OP_VERIFY: VERIFY4res opverify; case OP_WRITE: WRITE4res opwrite; case OP_RELEASE_LOCKOWNER: RELEASE_LOCKOWNER4res -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 oprelease_lockowner; case OP_ILLEGAL: ILLEGAL4res opillegal; }; struct COMPOUND4args { utf8string tag; uint32_t minorversion; nfs_argop4 argarray<>; }; @@ -12570,21 +12950,21 @@ struct CB_GETATTR4resok { fattr4 obj_attributes; }; union CB_GETATTR4res switch (nfsstat4 status) { case NFS4_OK: CB_GETATTR4resok resok4; default: -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 void; }; /* * CB_RECALL: Recall an Open Delegation */ struct CB_RECALL4args { stateid4 stateid; bool truncate; @@ -12625,42 +13005,42 @@ struct CB_COMPOUND4args { utf8string tag; uint32_t minorversion; uint32_t callback_ident; nfs_cb_argop4 argarray<>; }; struct CB_COMPOUND4res { -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 nfsstat4 status; utf8string tag; nfs_cb_resop4 resarray<>; }; /* * Program number is in the transient range since the client * will assign the exact transient program number and provide * that to the server via the SETCLIENTID operation. */ program NFS4_CALLBACK { version NFS_CB { void CB_NULL(void) = 0; CB_COMPOUND4res CB_COMPOUND(CB_COMPOUND4args) = 1; } = 1; } = 0x40000000; -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 19. Bibliography [Floyd] S. Floyd, V. Jacobson, "The Synchronization of Periodic Routing Messages," IEEE/ACM Transactions on Networking, 2(2), pp. 122-136, April 1994. [Gray] C. Gray, D. Cheriton, "Leases: An Efficient Fault-Tolerant Mechanism @@ -12694,21 +13074,21 @@ Association, Berkeley, CA, January 1991. Describes performance work in tuning the 4.3BSD Reno NFS implementation. Describes performance improvement (reduced CPU loading) through elimination of data copies. [Mogul] Mogul, Jeffrey C., "A Recovery Protocol for Spritely NFS," USENIX File System Workshop Proceedings, Ann Arbor, MI, USENIX Association, Berkeley, CA, May 1992. Second paper on Spritely NFS proposes a lease-based scheme for recovering state of consistency protocol. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 [Nowicki] Nowicki, Bill, "Transport Issues in the Network File System," ACM SIGCOMM newsletter Computer Communication Review, April 1989. A brief description of the basis for the dynamic retransmission work. [Pawlowski] Pawlowski, Brian, Ron Hixon, Mark Stein, Joseph Tumminaro, "Network Computing in the UNIX and IBM Mainframe Environment," Uniforum `89 Conf. Proc., (1989) Description of an NFS server implementation for @@ -12741,21 +13121,21 @@ [RFC1831] Srinivasan, R., "RPC: Remote Procedure Call Protocol Specification Version 2", RFC1831, Sun Microsystems, Inc., August 1995. http://www.ietf.org/rfc/rfc1831.txt [RFC1832] Srinivasan, R., "XDR: External Data Representation Standard", RFC1832, Sun Microsystems, Inc., August 1995. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 http://www.ietf.org/rfc/rfc1832.txt [RFC1833] Srinivasan, R., "Binding Protocols for ONC RPC Version 2", RFC1833, Sun Microsystems, Inc., August 1995. http://www.ietf.org/rfc/rfc1833.txt [RFC1884] @@ -12787,21 +13167,21 @@ Microsystems, Inc., October 1996 http://www.ietf.org/rfc/rfc2055.txt [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC2119, Harvard University, March 1997 http://www.ietf.org/rfc/rfc2119.txt -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 [RFC2152] Goldsmith, D., "UTF-7 A Mail-Safe Transformation Format of Unicode", RFC2152, Apple Computer, Inc., May 1997 http://www.ietf.org/rfc/rfc2152.txt [RFC2203] Eisler, M., Chiu, A., Ling, L., "RPCSEC_GSS Protocol Specification", RFC2203, Sun Microsystems, Inc., August 1995. @@ -12819,44 +13199,38 @@ RFC2277, UNINETT, January 1998. http://www.ietf.org/rfc/rfc2277.txt [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC2279, Alis Technologies, January 1998. http://www.ietf.org/rfc/rfc2279.txt - [RFC2581] - Allman, M., Paxson, V., Stevens, W., "TCP Congestion Control", - RFC2581, April 1999. - - http://www.ietf.org/rfc/rfc2581.txt - [RFC2623] Eisler, M., "NFS Version 2 and Version 3 Security Issues and the NFS Protocol's Use of RPCSEC_GSS and Kerberos V5", RFC2623, Sun Microsystems, June 1999 http://www.ietf.org/rfc/rfc2623.txt [RFC2624] Shepler, S., "NFS Version 4 Design Considerations", RFC2624, Sun - -Draft Specification NFS version 4 Protocol August 2002 - Microsystems, June 1999 http://www.ietf.org/rfc/rfc2624.txt [RFC2743] Linn, J., "Generic Security Service Application Program Interface, + +Draft Specification NFS version 4 Protocol September 2002 + Version 2, Update 1", RFC2743, RSA Laboratories, January 2000. http://www.ietf.org/rfc/rfc2743.txt [RFC2755] Chiu, A., Eisler, M., Callaghan, B., "Security Negotiation for WebNFS" , RFC2755, Sun Microsystems, June 2000 http://www.ietf.org/rfc/rfc2847.txt @@ -12883,36 +13257,36 @@ standard NFS. The issues of recovery in a stateful environment are covered in [Mogul]. [Unicode1] The Unicode Consortium, "The Unicode Standard, Version 3.0", Addison-Wesley Developers Press, Reading, MA, 2000. ISBN 0-201- 61633-5. More information available at: http://www.unicode.org/ -Draft Specification NFS version 4 Protocol August 2002 - [Unicode2] "Unsupported Scripts" Unicode, Inc., The Unicode Consortium, P.O. Box 700519, San Jose, CA 95710-0519 USA, September 1999 http://www.unicode.org/unicode/standard/unsupported.html +Draft Specification NFS version 4 Protocol September 2002 + [XNFS] The Open Group, Protocols for Interworking: XNFS, Version 3W, The Open Group, 1010 El Camino Real Suite 380, Menlo Park, CA 94025, ISBN 1-85912-184-5, February 1998. HTML version available: http://www.opengroup.org -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 20. Authors 20.1. Editor's Address Spencer Shepler Sun Microsystems, Inc. 7808 Moonflower Drive Austin, Texas 78750 @@ -12947,47 +13321,47 @@ Waltham, MA 02451 Phone: +1 781-768-5347 E-mail: dnoveck@netapp.com David Robinson Sun Microsystems, Inc. 5300 Riata Park Court Austin, TX 78727 -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 Phone: +1 650-786-5088 E-mail: david.robinson@sun.com Robert Thurlow Sun Microsystems, Inc. 500 Eldorado Blvd. Broomfield, CO 80021 Phone: +1 650-786-5096 E-mail: robert.thurlow@sun.com 20.3. Acknowledgements - The author thanks and acknowledges: + The authors thank and acknowledges: Neil Brown for his extensive review and comments of various drafts. Andy Adamson, Jim Rees, and Kendrick Smith from the CITI organization at the University of Michigan for their implementation efforts and feedback on the protocol specification. Mike Kupfer for his review of the file locking and ACL mechanisms. Alan Yoder for his input to ACL mechanisms. Peter Astrand for his close review of the protocol - specification. Ran Atkinson for his constant reminder that user's do + specification. Ran Atkinson for his constant reminder that users do matter. -Draft Specification NFS version 4 Protocol August 2002 +Draft Specification NFS version 4 Protocol September 2002 21. Full Copyright Statement "Copyright (C) The Internet Society (2000-2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any