draft-ietf-nfsv4-minorversion2-16.txt   draft-ietf-nfsv4-minorversion2-17.txt 
NFSv4 T. Haynes NFSv4 T. Haynes, Ed.
Internet-Draft Editor Internet-Draft NetApp
Intended status: Standards Track October 18, 2012 Intended status: Standards Track November 27, 2012
Expires: April 21, 2013 Expires: May 31, 2013
NFS Version 4 Minor Version 2 NFS Version 4 Minor Version 2
draft-ietf-nfsv4-minorversion2-16.txt draft-ietf-nfsv4-minorversion2-17.txt
Abstract Abstract
This Internet-Draft describes NFS version 4 minor version two, This Internet-Draft describes NFS version 4 minor version two,
focusing mainly on the protocol extensions made from NFS version 4 focusing mainly on the protocol extensions made from NFS version 4
minor version 0 and NFS version 4 minor version 1. Major extensions minor version 0 and NFS version 4 minor version 1. Major extensions
introduced in NFS version 4 minor version two include: Server-side introduced in NFS version 4 minor version two include: Server-side
Copy, Application I/O Advise, Space Reservations, Sparse Files, Copy, Application I/O Advise, Space Reservations, Sparse Files,
Application Data Blocks, and Labeled NFS. Application Data Blocks, and Labeled NFS.
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This Internet-Draft will expire on April 21, 2013. This Internet-Draft will expire on May 31, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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1.2. Scope of This Document . . . . . . . . . . . . . . . . . 5 1.2. Scope of This Document . . . . . . . . . . . . . . . . . 5
1.3. NFSv4.2 Goals . . . . . . . . . . . . . . . . . . . . . . 5 1.3. NFSv4.2 Goals . . . . . . . . . . . . . . . . . . . . . . 5
1.4. Overview of NFSv4.2 Features . . . . . . . . . . . . . . 6 1.4. Overview of NFSv4.2 Features . . . . . . . . . . . . . . 6
1.4.1. Server-side Copy . . . . . . . . . . . . . . . . . . . 6 1.4.1. Server-side Copy . . . . . . . . . . . . . . . . . . . 6
1.4.2. Application I/O Advise . . . . . . . . . . . . . . . . 6 1.4.2. Application I/O Advise . . . . . . . . . . . . . . . . 6
1.4.3. Sparse Files . . . . . . . . . . . . . . . . . . . . . 6 1.4.3. Sparse Files . . . . . . . . . . . . . . . . . . . . . 6
1.4.4. Space Reservation . . . . . . . . . . . . . . . . . . 6 1.4.4. Space Reservation . . . . . . . . . . . . . . . . . . 6
1.4.5. Application Data Hole (ADH) Support . . . . . . . . . 6 1.4.5. Application Data Hole (ADH) Support . . . . . . . . . 6
1.4.6. Labeled NFS . . . . . . . . . . . . . . . . . . . . . 6 1.4.6. Labeled NFS . . . . . . . . . . . . . . . . . . . . . 6
1.5. Differences from NFSv4.1 . . . . . . . . . . . . . . . . 7 1.5. Differences from NFSv4.1 . . . . . . . . . . . . . . . . 7
2. Server-side Copy . . . . . . . . . . . . . . . . . . . . . . . 7 2. Minor Versioning . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 7 3. Server-side Copy . . . . . . . . . . . . . . . . . . . . . . . 10
2.2. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7 3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 10
2.2.1. Overview of Copy Operations . . . . . . . . . . . . . 8 3.2. Protocol Overview . . . . . . . . . . . . . . . . . . . . 11
2.2.2. Locking the Files . . . . . . . . . . . . . . . . . . 9 3.2.1. Overview of Copy Operations . . . . . . . . . . . . . 11
2.2.3. Intra-Server Copy . . . . . . . . . . . . . . . . . . 9 3.2.2. Locking the Files . . . . . . . . . . . . . . . . . . 12
2.2.4. Inter-Server Copy . . . . . . . . . . . . . . . . . . 10 3.2.3. Intra-Server Copy . . . . . . . . . . . . . . . . . . 12
2.2.5. Server-to-Server Copy Protocol . . . . . . . . . . . . 14 3.2.4. Inter-Server Copy . . . . . . . . . . . . . . . . . . 14
2.3. Requirements for Operations . . . . . . . . . . . . . . . 15 3.2.5. Server-to-Server Copy Protocol . . . . . . . . . . . . 18
2.3.1. netloc4 - Network Locations . . . . . . . . . . . . . 16 3.3. Requirements for Operations . . . . . . . . . . . . . . . 19
2.3.2. Copy Offload Stateids . . . . . . . . . . . . . . . . 16 3.3.1. netloc4 - Network Locations . . . . . . . . . . . . . 20
2.4. Security Considerations . . . . . . . . . . . . . . . . . 17 3.3.2. Copy Offload Stateids . . . . . . . . . . . . . . . . 20
2.4.1. Inter-Server Copy Security . . . . . . . . . . . . . . 17 3.4. Security Considerations . . . . . . . . . . . . . . . . . 21
3. Support for Application IO Hints . . . . . . . . . . . . . . . 25 3.4.1. Inter-Server Copy Security . . . . . . . . . . . . . . 21
4. Sparse Files . . . . . . . . . . . . . . . . . . . . . . . . . 25 4. Support for Application IO Hints . . . . . . . . . . . . . . . 29
4.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 25 5. Sparse Files . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 26 5.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 29
4.3. New Operations . . . . . . . . . . . . . . . . . . . . . 26 5.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 30
4.3.1. READ_PLUS . . . . . . . . . . . . . . . . . . . . . . 27 5.3. New Operations . . . . . . . . . . . . . . . . . . . . . 30
4.3.2. WRITE_PLUS . . . . . . . . . . . . . . . . . . . . . . 27 5.3.1. READ_PLUS . . . . . . . . . . . . . . . . . . . . . . 31
5. Space Reservation . . . . . . . . . . . . . . . . . . . . . . 27 5.3.2. WRITE_PLUS . . . . . . . . . . . . . . . . . . . . . . 31
5.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 27 6. Space Reservation . . . . . . . . . . . . . . . . . . . . . . 31
6. Application Data Hole Support . . . . . . . . . . . . . . . . 29 6.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 31
6.1. Generic Framework . . . . . . . . . . . . . . . . . . . . 30 7. Application Data Hole Support . . . . . . . . . . . . . . . . 33
6.1.1. Data Hole Representation . . . . . . . . . . . . . . . 31 7.1. Generic Framework . . . . . . . . . . . . . . . . . . . . 34
6.1.2. Data Content . . . . . . . . . . . . . . . . . . . . . 31 7.1.1. Data Hole Representation . . . . . . . . . . . . . . . 35
6.2. An Example of Detecting Corruption . . . . . . . . . . . 32 7.1.2. Data Content . . . . . . . . . . . . . . . . . . . . . 35
6.3. Example of READ_PLUS . . . . . . . . . . . . . . . . . . 33 7.2. An Example of Detecting Corruption . . . . . . . . . . . 36
7. Labeled NFS . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.3. Example of READ_PLUS . . . . . . . . . . . . . . . . . . 37
7.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 34 8. Labeled NFS . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 35 8.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 38
7.3. MAC Security Attribute . . . . . . . . . . . . . . . . . 35 8.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 39
7.3.1. Delegations . . . . . . . . . . . . . . . . . . . . . 36 8.3. MAC Security Attribute . . . . . . . . . . . . . . . . . 39
7.3.2. Permission Checking . . . . . . . . . . . . . . . . . 36 8.3.1. Delegations . . . . . . . . . . . . . . . . . . . . . 40
7.3.3. Object Creation . . . . . . . . . . . . . . . . . . . 36 8.3.2. Permission Checking . . . . . . . . . . . . . . . . . 40
7.3.4. Existing Objects . . . . . . . . . . . . . . . . . . . 37 8.3.3. Object Creation . . . . . . . . . . . . . . . . . . . 40
7.3.5. Label Changes . . . . . . . . . . . . . . . . . . . . 37 8.3.4. Existing Objects . . . . . . . . . . . . . . . . . . . 41
7.4. pNFS Considerations . . . . . . . . . . . . . . . . . . . 37 8.3.5. Label Changes . . . . . . . . . . . . . . . . . . . . 41
7.5. Discovery of Server Labeled NFS Support . . . . . . . . . 38 8.4. pNFS Considerations . . . . . . . . . . . . . . . . . . . 41
7.6. MAC Security NFS Modes of Operation . . . . . . . . . . . 38 8.5. Discovery of Server Labeled NFS Support . . . . . . . . . 42
7.6.1. Full Mode . . . . . . . . . . . . . . . . . . . . . . 38 8.6. MAC Security NFS Modes of Operation . . . . . . . . . . . 42
7.6.2. Guest Mode . . . . . . . . . . . . . . . . . . . . . . 40 8.6.1. Full Mode . . . . . . . . . . . . . . . . . . . . . . 42
7.7. Security Considerations . . . . . . . . . . . . . . . . . 40 8.6.2. Guest Mode . . . . . . . . . . . . . . . . . . . . . . 44
8. Sharing change attribute implementation details with NFSv4 8.7. Security Considerations . . . . . . . . . . . . . . . . . 44
clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 9. Sharing change attribute implementation details with NFSv4
8.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 41 clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9. Security Considerations . . . . . . . . . . . . . . . . . . . 41 9.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 45
10. Error Values . . . . . . . . . . . . . . . . . . . . . . . . . 41 10. Security Considerations . . . . . . . . . . . . . . . . . . . 45
10.1. Error Definitions . . . . . . . . . . . . . . . . . . . . 42 11. Error Values . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.1.1. General Errors . . . . . . . . . . . . . . . . . . . . 42 11.1. Error Definitions . . . . . . . . . . . . . . . . . . . . 46
10.1.2. Server to Server Copy Errors . . . . . . . . . . . . . 42 11.1.1. General Errors . . . . . . . . . . . . . . . . . . . . 46
10.1.3. Labeled NFS Errors . . . . . . . . . . . . . . . . . . 43 11.1.2. Server to Server Copy Errors . . . . . . . . . . . . . 46
10.2. New Operations and Their Valid Errors . . . . . . . . . . 43 11.1.3. Labeled NFS Errors . . . . . . . . . . . . . . . . . . 47
10.3. New Callback Operations and Their Valid Errors . . . . . 46 11.2. New Operations and Their Valid Errors . . . . . . . . . . 47
11. New File Attributes . . . . . . . . . . . . . . . . . . . . . 47 11.3. New Callback Operations and Their Valid Errors . . . . . 50
11.1. New RECOMMENDED Attributes - List and Definition 12. New File Attributes . . . . . . . . . . . . . . . . . . . . . 51
References . . . . . . . . . . . . . . . . . . . . . . . 47 12.1. New RECOMMENDED Attributes - List and Definition
11.2. Attribute Definitions . . . . . . . . . . . . . . . . . . 48 References . . . . . . . . . . . . . . . . . . . . . . . 51
12. Operations: REQUIRED, RECOMMENDED, or OPTIONAL . . . . . . . . 51 12.2. Attribute Definitions . . . . . . . . . . . . . . . . . . 52
13. NFSv4.2 Operations . . . . . . . . . . . . . . . . . . . . . . 55 13. Operations: REQUIRED, RECOMMENDED, or OPTIONAL . . . . . . . . 55
13.1. Operation 59: COPY - Initiate a server-side copy . . . . 55 14. NFSv4.2 Operations . . . . . . . . . . . . . . . . . . . . . . 59
13.2. Operation 60: OFFLOAD_ABORT - Cancel a server-side 14.1. Operation 59: COPY - Initiate a server-side copy . . . . 59
copy . . . . . . . . . . . . . . . . . . . . . . . . . . 62 14.2. Operation 60: OFFLOAD_ABORT - Cancel a server-side
13.3. Operation 61: COPY_NOTIFY - Notify a source server of copy . . . . . . . . . . . . . . . . . . . . . . . . . . 65
a future copy . . . . . . . . . . . . . . . . . . . . . . 63 14.3. Operation 61: COPY_NOTIFY - Notify a source server of
13.4. Operation 62: OFFLOAD_REVOKE - Revoke a destination a future copy . . . . . . . . . . . . . . . . . . . . . . 66
server's copy privileges . . . . . . . . . . . . . . . . 64 14.4. Operation 62: OFFLOAD_REVOKE - Revoke a destination
13.5. Operation 63: OFFLOAD_STATUS - Poll for status of a server's copy privileges . . . . . . . . . . . . . . . . 68
server-side copy . . . . . . . . . . . . . . . . . . . . 65 14.5. Operation 63: OFFLOAD_STATUS - Poll for status of a
13.6. Modification to Operation 42: EXCHANGE_ID - server-side copy . . . . . . . . . . . . . . . . . . . . 69
Instantiate Client ID . . . . . . . . . . . . . . . . . . 66 14.6. Modification to Operation 42: EXCHANGE_ID -
13.7. Operation 64: WRITE_PLUS . . . . . . . . . . . . . . . . 67 Instantiate Client ID . . . . . . . . . . . . . . . . . . 70
13.8. Operation 67: IO_ADVISE - Application I/O access 14.7. Operation 64: WRITE_PLUS . . . . . . . . . . . . . . . . 71
pattern hints . . . . . . . . . . . . . . . . . . . . . . 72 14.8. Operation 67: IO_ADVISE - Application I/O access
13.9. Changes to Operation 51: LAYOUTRETURN . . . . . . . . . . 78 pattern hints . . . . . . . . . . . . . . . . . . . . . . 76
13.10. Operation 65: READ_PLUS . . . . . . . . . . . . . . . . . 81 14.9. Changes to Operation 51: LAYOUTRETURN . . . . . . . . . . 82
13.11. Operation 66: SEEK . . . . . . . . . . . . . . . . . . . 86 14.10. Operation 65: READ_PLUS . . . . . . . . . . . . . . . . . 85
14. NFSv4.2 Callback Operations . . . . . . . . . . . . . . . . . 87 14.11. Operation 66: SEEK . . . . . . . . . . . . . . . . . . . 90
14.1. Operation 15: CB_OFFLOAD - Report results of an 15. NFSv4.2 Callback Operations . . . . . . . . . . . . . . . . . 91
asynchronous operation . . . . . . . . . . . . . . . . . 87 15.1. Operation 15: CB_OFFLOAD - Report results of an
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 88 asynchronous operation . . . . . . . . . . . . . . . . . 91
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 89 16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 92
16.1. Normative References . . . . . . . . . . . . . . . . . . 89 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 93
16.2. Informative References . . . . . . . . . . . . . . . . . 89 17.1. Normative References . . . . . . . . . . . . . . . . . . 93
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 90 17.2. Informative References . . . . . . . . . . . . . . . . . 93
Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 91 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 94
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 92 Appendix B. RFC Editor Notes . . . . . . . . . . . . . . . . . . 95
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 96
1. Introduction 1. Introduction
1.1. The NFS Version 4 Minor Version 2 Protocol 1.1. The NFS Version 4 Minor Version 2 Protocol
The NFS version 4 minor version 2 (NFSv4.2) protocol is the third The NFS version 4 minor version 2 (NFSv4.2) protocol is the third
minor version of the NFS version 4 (NFSv4) protocol. The first minor minor version of the NFS version 4 (NFSv4) protocol. The first minor
version, NFSv4.0, is described in [9] and the second minor version, version, NFSv4.0, is described in [9] and the second minor version,
NFSv4.1, is described in [1]. It follows the guidelines for minor NFSv4.1, is described in [1]. It follows the guidelines for minor
versioning that are listed in Section 11 of [9]. versioning that are listed in Section 11 of [9].
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A traditional file copy from one server to another results in the A traditional file copy from one server to another results in the
data being put on the network twice - source to client and then data being put on the network twice - source to client and then
client to destination. New operations are introduced to allow the client to destination. New operations are introduced to allow the
client to authorize the two servers to interact directly. As this client to authorize the two servers to interact directly. As this
copy can be lengthy, asynchronous support is also provided. copy can be lengthy, asynchronous support is also provided.
1.4.2. Application I/O Advise 1.4.2. Application I/O Advise
Applications and clients want to advise the server as to expected I/O Applications and clients want to advise the server as to expected I/O
behavior. Using IO_ADVISE (see Section 13.8) to communicate future behavior. Using IO_ADVISE (see Section 14.8) to communicate future
I/O behavior such as whether a file will be accessed sequentially or I/O behavior such as whether a file will be accessed sequentially or
randomly, and whether a file will or will not be accessed in the near randomly, and whether a file will or will not be accessed in the near
future, allows servers to optimize future I/O requests for a file by, future, allows servers to optimize future I/O requests for a file by,
for example, prefetching or evicting data. This operation can be for example, prefetching or evicting data. This operation can be
used to support the posix_fadvise function as well as other used to support the posix_fadvise function as well as other
applications such as databases and video editors. applications such as databases and video editors.
1.4.3. Sparse Files 1.4.3. Sparse Files
Sparse files are ones which have unallocated data blocks as holes in Sparse files are ones which have unallocated data blocks as holes in
the file. Such holes are typically transferred as 0s during I/O. the file. Such holes are typically transferred as 0s during I/O.
READ_PLUS (see Section 13.10) allows a server to send back to the READ_PLUS (see Section 14.10) allows a server to send back to the
client metadata describing the hole and WRITE_PLUS (see Section 13.7) client metadata describing the hole and WRITE_PLUS (see Section 14.7)
allows the client to punch holes into a file. In addition, SEEK (see allows the client to punch holes into a file. In addition, SEEK (see
Section 13.11) is provided to scan for the next hole or data from a Section 14.11) is provided to scan for the next hole or data from a
given location. given location.
1.4.4. Space Reservation 1.4.4. Space Reservation
When a file is sparse, one concern applications have is ensuring that When a file is sparse, one concern applications have is ensuring that
there will always be enough data blocks available for the file during there will always be enough data blocks available for the file during
future writes. A new attribute, space_reserved (see Section 11.2.4) future writes. A new attribute, space_reserved (see Section 12.2.4)
provides the client a guarantee that space will be available. provides the client a guarantee that space will be available.
1.4.5. Application Data Hole (ADH) Support 1.4.5. Application Data Hole (ADH) Support
Some applications treat a file as if it were a disk and as such want Some applications treat a file as if it were a disk and as such want
to initialize (or format) the file image. We extend both READ_PLUS to initialize (or format) the file image. We extend both READ_PLUS
and WRITE_PLUS to understand this metadata as a new form of a hole. and WRITE_PLUS to understand this metadata as a new form of a hole.
1.4.6. Labeled NFS 1.4.6. Labeled NFS
While both clients and servers can employ Mandatory Access Control While both clients and servers can employ Mandatory Access Control
(MAC) security models to enforce data access, there has been no (MAC) security models to enforce data access, there has been no
protocol support to allow full interoperability. A new file object protocol support to allow full interoperability. A new file object
attribute, sec_label (see Section 11.2.2) allows for the server to attribute, sec_label (see Section 12.2.2) allows for the server to
store and enforce MAC labels. The format of the sec_label store and enforce MAC labels. The format of the sec_label
accommodates any MAC security system. accommodates any MAC security system.
1.5. Differences from NFSv4.1 1.5. Differences from NFSv4.1
In NFSv4.1, the only way to introduce new variants of an operation In NFSv4.1, the only way to introduce new variants of an operation
was to introduce a new operation. I.e., READ becomes either READ2 or was to introduce a new operation. I.e., READ becomes either READ2 or
READ_PLUS. With the use of discriminated unions as parameters to READ_PLUS. With the use of discriminated unions as parameters to
such functions in NFSv4.2, it is possible to add a new arm in a such functions in NFSv4.2, it is possible to add a new arm in a
subsequent minor version. And it is also possible to move such an subsequent minor version. And it is also possible to move such an
operation from OPTIONAL/RECOMMENDED to REQUIRED. Forcing an operation from OPTIONAL/RECOMMENDED to REQUIRED. Forcing an
implementation to adopt each arm of a discriminated union at such a implementation to adopt each arm of a discriminated union at such a
time does not meet the spirit of the minor versioning rules. As time does not meet the spirit of the minor versioning rules. As
such, new arms of a discriminated union MUST follow the same such, new arms of a discriminated union MUST follow the same
guidelines for minor versioning as operations in NFSv4.1 - i.e., they guidelines for minor versioning as operations in NFSv4.1 - i.e., they
may not be made REQUIRED. To support this, a new error code, may not be made REQUIRED. To support this, a new error code,
NFS4ERR_UNION_NOTSUPP, is introduced which allows the server to NFS4ERR_UNION_NOTSUPP, is introduced which allows the server to
communicate to the client that the operation is supported, but the communicate to the client that the operation is supported, but the
specific arm of the discriminated union is not. specific arm of the discriminated union is not.
2. Server-side Copy 2. Minor Versioning
2.1. Introduction To address the requirement of an NFS protocol that can evolve as the
need arises, the NFSv4 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 will be documented in one or more
Standards Track RFCs. Minor version 0 of the NFSv4 protocol is
represented by [9], minor version 1 by [1], and minor version 2 by
this document. The COMPOUND and CB_COMPOUND procedures support the
encoding of the minor version being requested by the client.
The following items represent the basic rules for the development of
minor versions. Note that a future minor version may modify or add
to the following rules as part of the minor version definition.
1. Procedures are not added or deleted.
To maintain the general RPC model, NFSv4 minor versions will not
add to or delete procedures from the NFS program.
2. Minor versions may add operations to the COMPOUND and
CB_COMPOUND procedures.
The addition of operations to the COMPOUND and CB_COMPOUND
procedures does not affect the RPC model.
* Minor versions may append attributes to the bitmap4 that
represents sets of attributes and to the fattr4 that
represents sets of attribute values.
This allows for the expansion of the attribute model to allow
for future growth or adaptation.
* Minor version X must append any new attributes after the last
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 would
be too burdensome.
3. Minor versions must not modify the structure of an existing
operation's arguments or results.
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:
* adding bits to flag fields, such as new attributes to
GETATTR's bitmap4 data type, and providing corresponding
variants of opaque arrays, such as a notify4 used together
with such bitmaps
* adding bits to existing attributes like ACLs that have flag
words
* extending enumerated types (including NFS4ERR_*) with new
values
* adding cases to a switched union
4. Note that when adding new cases to a switched union, a minor
version must not make new cases be REQUIRED. While the
encapsulating operation may be REQUIRED, the new cases (the
specific arm of the discriminated union) is not. The error code
NFS4ERR_UNION_NOTSUPP is used to notifify the client when the
server does not support such a case.
5. Minor versions must not modify the structure of existing
attributes.
6. Minor versions must not delete operations.
This prevents the potential reuse of a particular operation
"slot" in a future minor version.
7. Minor versions must not delete attributes.
8. Minor versions must not delete flag bits or enumeration values.
9. Minor versions may declare an operation MUST NOT be implemented.
Specifying that an operation MUST NOT be implemented is
equivalent to obsoleting an operation. For the client, it means
that the operation MUST NOT be sent to the server. For the
server, an NFS error can be returned as opposed to "dropping"
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.
1. Minor versions may declare that an attribute MUST NOT be
implemented.
2. Minor versions may declare that a flag bit or enumeration
value MUST NOT be implemented.
10. Minor versions may declare an operation to be OBSOLESCENT, which
indicates an intention to remove the operation (i.e., make it
MANDATORY TO NOT implement) in a subsequent minor version. Such
labeling is separate from the question of whether the operation
is REQUIRED or RECOMMENDED or OPTIONAL in the current minor
version. An operation may be both REQUIRED for the given minor
version and marked OBSOLESCENT, with the expectation that it
will be MANDATORY TO NOT implement in the next (or other
subsequent) minor version.
11. Note that the early notification of operation obsolescence is
put in place to mitigate the effects of design and
implementation mistakes, and to allow protocol development to
adapt to unexpected changes in the pace of implementation. Even
if an operation is marked OBSOLESCENT in a given minor version,
it may end up not being marked MANDATORY TO NOT implement in the
next minor version. In unusual circumstances, it might not be
marked OBSOLESCENT in a subsequent minor version, and never
become MANDATORY TO NOT implement.
12. Minor versions may downgrade features from REQUIRED to
RECOMMENDED, from RECOMMENDED to OPTIONAL, or from OPIONAL to
MANDATORY TO NOT implement. Also, if a feature was marked as
OBSOLESCENT in the prior minor version, it may be downgraded
from REQUIRED to OPTIONAL from RECOMMENDED to MANDATORY TO NOT
implement, or from REQUIRED to MANDATORY TO NOT implement.
13. Minor versions may upgrade features from OPTIONAL to
RECOMMENDED, or RECOMMENDED to REQUIRED. Also, if a feature was
marked as OBSOLESCENT in the prior minor version, it may be
upgraded to not be OBSOLESCENT.
14. A client and server that support minor version X SHOULD support
minor versions 0 through X-1 as well.
15. Except for infrastructural changes, a minor version must not
introduce REQUIRED new features.
This rule allows for the introduction of new functionality and
forces the use of implementation experience before designating a
feature as REQUIRED. On the other hand, some classes of
features are infrastructural and have broad effects. Allowing
infrastructural features to be RECOMMENDED or OPTIONAL
complicates implementation of the minor version.
16. 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.
3. Server-side Copy
3.1. Introduction
The server-side copy feature provides a mechanism for the NFS client The server-side copy feature provides a mechanism for the NFS client
to perform a file copy on the server without the data being to perform a file copy on the server without the data being
transmitted back and forth over the network. Without this feature, transmitted back and forth over the network. Without this feature,
an NFS client copies data from one location to another by reading the an NFS client copies data from one location to another by reading the
data from the server over the network, and then writing the data back data from the server over the network, and then writing the data back
over the network to the server. Using this server-side copy over the network to the server. Using this server-side copy
operation, the client is able to instruct the server to copy the data operation, the client is able to instruct the server to copy the data
locally without the data being sent back and forth over the network locally without the data being sent back and forth over the network
unnecessarily. unnecessarily.
If the source object and destination object are on different file If the source object and destination object are on different file
servers, the file servers will communicate with one another to servers, the file servers will communicate with one another to
perform the copy operation. The server-to-server protocol by which perform the copy operation. The server-to-server protocol by which
this is accomplished is not defined in this document. this is accomplished is not defined in this document.
2.2. Protocol Overview 3.2. Protocol Overview
The server-side copy offload operations support both intra-server and The server-side copy offload operations support both intra-server and
inter-server file copies. An intra-server copy is a copy in which inter-server file copies. An intra-server copy is a copy in which
the source file and destination file reside on the same server. In the source file and destination file reside on the same server. In
an inter-server copy, the source file and destination file are on an inter-server copy, the source file and destination file are on
different servers. In both cases, the copy may be performed different servers. In both cases, the copy may be performed
synchronously or asynchronously. synchronously or asynchronously.
Throughout the rest of this document, we refer to the NFS server Throughout the rest of this document, we refer to the NFS server
containing the source file as the "source server" and the NFS server containing the source file as the "source server" and the NFS server
skipping to change at page 8, line 32 skipping to change at page 11, line 44
ONC RPC Federated Filesystem protocol [11] to perform the copy. ONC RPC Federated Filesystem protocol [11] to perform the copy.
Specifically the client can determine the source junction's Specifically the client can determine the source junction's
attributes using the FEDFS_LOOKUP_FSN procedure and create a attributes using the FEDFS_LOOKUP_FSN procedure and create a
duplicate junction using the FEDFS_CREATE_JUNCTION procedure. duplicate junction using the FEDFS_CREATE_JUNCTION procedure.
For the inter-server copy, the operations are defined to be For the inter-server copy, the operations are defined to be
compatible with the traditional copy authentication approach. The compatible with the traditional copy authentication approach. The
client and user are authorized at the source for reading. Then they client and user are authorized at the source for reading. Then they
are authorized at the destination for writing. are authorized at the destination for writing.
2.2.1. Overview of Copy Operations 3.2.1. Overview of Copy Operations
COPY_NOTIFY: For inter-server copies, the client sends this COPY_NOTIFY: For inter-server copies, the client sends this
operation to the source server to notify it of a future file copy operation to the source server to notify it of a future file copy
from a given destination server for the given user. from a given destination server for the given user.
(Section 13.3) (Section 14.3)
OFFLOAD_REVOKE: Also for inter-server copies, the client sends this OFFLOAD_REVOKE: Also for inter-server copies, the client sends this
operation to the source server to revoke permission to copy a file operation to the source server to revoke permission to copy a file
for the given user. (Section 13.4) for the given user. (Section 14.4)
COPY: Used by the client to request a file copy. (Section 13.1) COPY: Used by the client to request a file copy. (Section 14.1)
OFFLOAD_ABORT: Used by the client to abort an asynchronous file OFFLOAD_ABORT: Used by the client to abort an asynchronous file
copy. (Section 13.2) copy. (Section 14.2)
OFFLOAD_STATUS: Used by the client to poll the status of an OFFLOAD_STATUS: Used by the client to poll the status of an
asynchronous file copy. (Section 13.5) asynchronous file copy. (Section 14.5)
CB_OFFLOAD: Used by the destination server to report the results of CB_OFFLOAD: Used by the destination server to report the results of
an asynchronous file copy to the client. (Section 14.1) an asynchronous file copy to the client. (Section 15.1)
2.2.2. Locking the Files 3.2.2. Locking the Files
Both the source and destination file may need to be locked to protect Both the source and destination file may need to be locked to protect
the content during the copy operations. A client can achieve this by the content during the copy operations. A client can achieve this by
a combination of OPEN and LOCK operations. I.e., either share or a combination of OPEN and LOCK operations. I.e., either share or
byte range locks might be desired. byte range locks might be desired.
2.2.3. Intra-Server Copy 3.2.3. Intra-Server Copy
To copy a file on a single server, the client uses a COPY operation. To copy a file on a single server, the client uses a COPY operation.
The server may respond to the copy operation with the final results The server may respond to the copy operation with the final results
of the copy or it may perform the copy asynchronously and deliver the of the copy or it may perform the copy asynchronously and deliver the
results using a CB_OFFLOAD operation callback. If the copy is results using a CB_OFFLOAD operation callback. If the copy is
performed asynchronously, the client may poll the status of the copy performed asynchronously, the client may poll the status of the copy
using OFFLOAD_STATUS or cancel the copy using OFFLOAD_ABORT. using OFFLOAD_STATUS or cancel the copy using OFFLOAD_ABORT.
A synchronous intra-server copy is shown in Figure 1. In this A synchronous intra-server copy is shown in Figure 1. In this
example, the NFS server chooses to perform the copy synchronously. example, the NFS server chooses to perform the copy synchronously.
skipping to change at page 10, line 46 skipping to change at page 14, line 38
|--- CLOSE --------------------------->| Client closes |--- CLOSE --------------------------->| Client closes
|<------------------------------------/| the destination file |<------------------------------------/| the destination file
| | | |
|--- CLOSE --------------------------->| Client closes |--- CLOSE --------------------------->| Client closes
|<------------------------------------/| the source file |<------------------------------------/| the source file
| | | |
| | | |
Figure 2: An asynchronous intra-server copy. Figure 2: An asynchronous intra-server copy.
2.2.4. Inter-Server Copy 3.2.4. Inter-Server Copy
A copy may also be performed between two servers. The copy protocol A copy may also be performed between two servers. The copy protocol
is designed to accommodate a variety of network topologies. As shown is designed to accommodate a variety of network topologies. As shown
in Figure 3, the client and servers may be connected by multiple in Figure 3, the client and servers may be connected by multiple
networks. In particular, the servers may be connected by a networks. In particular, the servers may be connected by a
specialized, high speed network (network 192.0.2.0/24 in the diagram) specialized, high speed network (network 192.0.2.0/24 in the diagram)
that does not include the client. The protocol allows the client to that does not include the client. The protocol allows the client to
setup the copy between the servers (over network 203.0.113.0/24 in setup the copy between the servers (over network 203.0.113.0/24 in
the diagram) and for the servers to communicate on the high speed the diagram) and for the servers to communicate on the high speed
network if they choose to do so. network if they choose to do so.
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| | | | | |
|--- LOCKU --->| | Only if LOCK was done |--- LOCKU --->| | Only if LOCK was done
|<------------------/| | |<------------------/| |
| | | | | |
|--- CLOSE --->| | Release open state |--- CLOSE --->| | Release open state
|<------------------/| | |<------------------/| |
| | | | | |
Figure 5: An asynchronous inter-server copy. Figure 5: An asynchronous inter-server copy.
2.2.5. Server-to-Server Copy Protocol 3.2.5. Server-to-Server Copy Protocol
The source server and destination server are not required to use a The source server and destination server are not required to use a
specific protocol to transfer the file data. The choice of what specific protocol to transfer the file data. The choice of what
protocol to use is ultimately the destination server's decision. protocol to use is ultimately the destination server's decision.
2.2.5.1. Using NFSv4.x as a Server-to-Server Copy Protocol 3.2.5.1. Using NFSv4.x as a Server-to-Server Copy Protocol
The destination server MAY use standard NFSv4.x (where x >= 1) to The destination server MAY use standard NFSv4.x (where x >= 1) to
read the data from the source server. If NFSv4.x is used for the read the data from the source server. If NFSv4.x is used for the
server-to-server copy protocol, the destination server can use the server-to-server copy protocol, the destination server can use the
filehandle contained in the COPY request with standard NFSv4.x filehandle contained in the COPY request with standard NFSv4.x
operations to read data from the source server. Specifically, the operations to read data from the source server. Specifically, the
destination server may use the NFSv4.x OPEN operation's CLAIM_FH destination server may use the NFSv4.x OPEN operation's CLAIM_FH
facility to open the file being copied and obtain an open stateid. facility to open the file being copied and obtain an open stateid.
Using the stateid, the destination server may then use NFSv4.x READ Using the stateid, the destination server may then use NFSv4.x READ
operations to read the file. operations to read the file.
2.2.5.2. Using an alternative Server-to-Server Copy Protocol 3.2.5.2. Using an alternative Server-to-Server Copy Protocol
In a homogeneous environment, the source and destination servers In a homogeneous environment, the source and destination servers
might be able to perform the file copy extremely efficiently using might be able to perform the file copy extremely efficiently using
specialized protocols. For example the source and destination specialized protocols. For example the source and destination
servers might be two nodes sharing a common file system format for servers might be two nodes sharing a common file system format for
the source and destination file systems. Thus the source and the source and destination file systems. Thus the source and
destination are in an ideal position to efficiently render the image destination are in an ideal position to efficiently render the image
of the source file to the destination file by replicating the file of the source file to the destination file by replicating the file
system formats at the block level. Another possibility is that the system formats at the block level. Another possibility is that the
source and destination might be two nodes sharing a common storage source and destination might be two nodes sharing a common storage
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destination server receives the source server's URL, it would use destination server receives the source server's URL, it would use
"_FH/0x12345" as the file name to pass to the FTP server listening on "_FH/0x12345" as the file name to pass to the FTP server listening on
port 9999 of s1.example.com. On port 9999 there would be a special port 9999 of s1.example.com. On port 9999 there would be a special
instance of the FTP service that understands how to convert NFS instance of the FTP service that understands how to convert NFS
filehandles to an open file descriptor (in many operating systems, filehandles to an open file descriptor (in many operating systems,
this would require a new system call, one which is the inverse of the this would require a new system call, one which is the inverse of the
makefh() function that the pre-NFSv4 MOUNT service needs). makefh() function that the pre-NFSv4 MOUNT service needs).
Authenticating and identifying the destination server to the source Authenticating and identifying the destination server to the source
server is also a challenge. Recommendations for how to accomplish server is also a challenge. Recommendations for how to accomplish
this are given in Section 2.4.1.2.4 and Section 2.4.1.4. this are given in Section 3.4.1.2.4 and Section 3.4.1.4.
2.3. Requirements for Operations 3.3. Requirements for Operations
The implementation of server-side copy is OPTIONAL by the client and The implementation of server-side copy is OPTIONAL by the client and
the server. However, in order to successfully copy a file, some the server. However, in order to successfully copy a file, some
operations MUST be supported by the client and/or server. operations MUST be supported by the client and/or server.
If a client desires an intra-server file copy, then it MUST support If a client desires an intra-server file copy, then it MUST support
the COPY and CB_OFFLOAD operations. If COPY returns a stateid, then the COPY and CB_OFFLOAD operations. If COPY returns a stateid, then
the client MAY use the OFFLOAD_ABORT and OFFLOAD_STATUS operations. the client MAY use the OFFLOAD_ABORT and OFFLOAD_STATUS operations.
If a client desires an inter-server file copy, then it MUST support If a client desires an inter-server file copy, then it MUST support
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Each operation is performed in the context of the user identified by Each operation is performed in the context of the user identified by
the ONC RPC credential of its containing COMPOUND or CB_COMPOUND the ONC RPC credential of its containing COMPOUND or CB_COMPOUND
request. For example, a OFFLOAD_ABORT operation issued by a given request. For example, a OFFLOAD_ABORT operation issued by a given
user indicates that a specified COPY operation initiated by the same user indicates that a specified COPY operation initiated by the same
user be canceled. Therefore a OFFLOAD_ABORT MUST NOT interfere with user be canceled. Therefore a OFFLOAD_ABORT MUST NOT interfere with
a copy of the same file initiated by another user. a copy of the same file initiated by another user.
An NFS server MAY allow an administrative user to monitor or cancel An NFS server MAY allow an administrative user to monitor or cancel
copy operations using an implementation specific interface. copy operations using an implementation specific interface.
2.3.1. netloc4 - Network Locations 3.3.1. netloc4 - Network Locations
The server-side copy operations specify network locations using the The server-side copy operations specify network locations using the
netloc4 data type shown below: netloc4 data type shown below:
enum netloc_type4 { enum netloc_type4 {
NL4_NAME = 0, NL4_NAME = 0,
NL4_URL = 1, NL4_URL = 1,
NL4_NETADDR = 2 NL4_NETADDR = 2
}; };
union netloc4 switch (netloc_type4 nl_type) { union netloc4 switch (netloc_type4 nl_type) {
skipping to change at page 16, line 39 skipping to change at page 20, line 39
UTF-8 string. If the netloc4 is of type NL4_NETADDR, the nl_addr UTF-8 string. If the netloc4 is of type NL4_NETADDR, the nl_addr
field MUST contain a valid netaddr4 as defined in Section 3.3.9 of field MUST contain a valid netaddr4 as defined in Section 3.3.9 of
[1]. [1].
When netloc4 values are used for an inter-server copy as shown in When netloc4 values are used for an inter-server copy as shown in
Figure 3, their values may be evaluated on the source server, Figure 3, their values may be evaluated on the source server,
destination server, and client. The network environment in which destination server, and client. The network environment in which
these systems operate should be configured so that the netloc4 values these systems operate should be configured so that the netloc4 values
are interpreted as intended on each system. are interpreted as intended on each system.
2.3.2. Copy Offload Stateids 3.3.2. Copy Offload Stateids
A server may perform a copy offload operation asynchronously. An A server may perform a copy offload operation asynchronously. An
asynchronous copy is tracked using a copy offload stateid. Copy asynchronous copy is tracked using a copy offload stateid. Copy
offload stateids are included in the COPY, OFFLOAD_ABORT, offload stateids are included in the COPY, OFFLOAD_ABORT,
OFFLOAD_STATUS, and CB_OFFLOAD operations. OFFLOAD_STATUS, and CB_OFFLOAD operations.
Section 8.2.4 of [1] specifies that stateids are valid until either Section 8.2.4 of [1] specifies that stateids are valid until either
(A) the client or server restart or (B) the client returns the (A) the client or server restart or (B) the client returns the
resource. resource.
A copy offload stateid will be valid until either (A) the client or A copy offload stateid will be valid until either (A) the client or
server restarts or (B) the client returns the resource by issuing a server restarts or (B) the client returns the resource by issuing a
OFFLOAD_ABORT operation or the client replies to a CB_OFFLOAD OFFLOAD_ABORT operation or the client replies to a CB_OFFLOAD
operation. operation.
A copy offload stateid's seqid MUST NOT be 0. In the context of a A copy offload stateid's seqid MUST NOT be 0. In the context of a
copy offload operation, it is ambiguous to indicate the most recent copy offload operation, it is ambiguous to indicate the most recent
copy offload operation using a stateid with seqid of 0. Therefore a copy offload operation using a stateid with seqid of 0. Therefore a
copy offload stateid with seqid of 0 MUST be considered invalid. copy offload stateid with seqid of 0 MUST be considered invalid.
2.4. Security Considerations 3.4. Security Considerations
The security considerations pertaining to NFSv4 [9] apply to this The security considerations pertaining to NFSv4 [9] apply to this
chapter. chapter.
The standard security mechanisms provide by NFSv4 [9] may be used to The standard security mechanisms provide by NFSv4 [9] may be used to
secure the protocol described in this chapter. secure the protocol described in this chapter.
NFSv4 clients and servers supporting the inter-server copy operations NFSv4 clients and servers supporting the inter-server copy operations
described in this chapter are REQUIRED to implement [4], including described in this chapter are REQUIRED to implement [4], including
the RPCSEC_GSSv3 privileges copy_from_auth and copy_to_auth. If the the RPCSEC_GSSv3 privileges copy_from_auth and copy_to_auth. If the
server-to-server copy protocol is ONC RPC based, the servers are also server-to-server copy protocol is ONC RPC based, the servers are also
REQUIRED to implement the RPCSEC_GSSv3 privilege copy_confirm_auth. REQUIRED to implement the RPCSEC_GSSv3 privilege copy_confirm_auth.
These requirements to implement are not requirements to use. NFSv4 These requirements to implement are not requirements to use. NFSv4
clients and servers are RECOMMENDED to use [4] to secure server-side clients and servers are RECOMMENDED to use [4] to secure server-side
copy operations. copy operations.
2.4.1. Inter-Server Copy Security 3.4.1. Inter-Server Copy Security
2.4.1.1. Requirements for Secure Inter-Server Copy 3.4.1.1. Requirements for Secure Inter-Server Copy
Inter-server copy is driven by several requirements: Inter-server copy is driven by several requirements:
o The specification MUST NOT mandate an inter-server copy protocol. o The specification MUST NOT mandate an inter-server copy protocol.
There are many ways to copy data. Some will be more optimal than There are many ways to copy data. Some will be more optimal than
others depending on the identities of the source server and others depending on the identities of the source server and
destination server. For example the source and destination destination server. For example the source and destination
servers might be two nodes sharing a common file system format for servers might be two nodes sharing a common file system format for
the source and destination file systems. Thus the source and the source and destination file systems. Thus the source and
destination are in an ideal position to efficiently render the destination are in an ideal position to efficiently render the
skipping to change at page 18, line 17 skipping to change at page 22, line 17
destination first have a "copying relationship" increases the destination first have a "copying relationship" increases the
administrative burden. However the specification MUST NOT administrative burden. However the specification MUST NOT
preclude implementations that require pre-configuration. preclude implementations that require pre-configuration.
o The specification MUST NOT mandate a trust relationship between o The specification MUST NOT mandate a trust relationship between
the source and destination server. The NFSv4 security model the source and destination server. The NFSv4 security model
requires mutual authentication between a principal on an NFS requires mutual authentication between a principal on an NFS
client and a principal on an NFS server. This model MUST continue client and a principal on an NFS server. This model MUST continue
with the introduction of COPY. with the introduction of COPY.
2.4.1.2. Inter-Server Copy with RPCSEC_GSSv3 3.4.1.2. Inter-Server Copy with RPCSEC_GSSv3
When the client sends a COPY_NOTIFY to the source server to expect When the client sends a COPY_NOTIFY to the source server to expect
the destination to attempt to copy data from the source server, it is the destination to attempt to copy data from the source server, it is
expected that this copy is being done on behalf of the principal expected that this copy is being done on behalf of the principal
(called the "user principal") that sent the RPC request that encloses (called the "user principal") that sent the RPC request that encloses
the COMPOUND procedure that contains the COPY_NOTIFY operation. The the COMPOUND procedure that contains the COPY_NOTIFY operation. The
user principal is identified by the RPC credentials. A mechanism user principal is identified by the RPC credentials. A mechanism
that allows the user principal to authorize the destination server to that allows the user principal to authorize the destination server to
perform the copy in a manner that lets the source server properly perform the copy in a manner that lets the source server properly
authenticate the destination's copy, and without allowing the authenticate the destination's copy, and without allowing the
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struct copy_confirm_auth_priv { struct copy_confirm_auth_priv {
/* equal to GSS_GetMIC() of cfap_shared_secret */ /* equal to GSS_GetMIC() of cfap_shared_secret */
opaque ccap_shared_secret_mic<>; opaque ccap_shared_secret_mic<>;
/* the NFSv4 user name that the user principal maps to */ /* the NFSv4 user name that the user principal maps to */
utf8str_mixed ccap_username; utf8str_mixed ccap_username;
/* equal to seq_num of rpc_gss_cred_vers_3_t */ /* equal to seq_num of rpc_gss_cred_vers_3_t */
unsigned int ccap_seq_num; unsigned int ccap_seq_num;
}; };
2.4.1.2.1. Establishing a Security Context 3.4.1.2.1. Establishing a Security Context
When the user principal wants to COPY a file between two servers, if When the user principal wants to COPY a file between two servers, if
it has not established copy_from_auth and copy_to_auth privileges on it has not established copy_from_auth and copy_to_auth privileges on
the servers, it establishes them: the servers, it establishes them:
o The user principal generates a secret it will share with the two o The user principal generates a secret it will share with the two
servers. This shared secret will be placed in the servers. This shared secret will be placed in the
cfap_shared_secret and ctap_shared_secret fields of the cfap_shared_secret and ctap_shared_secret fields of the
appropriate privilege data types, copy_from_auth_priv and appropriate privilege data types, copy_from_auth_priv and
copy_to_auth_priv. copy_to_auth_priv.
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rpc_gss3_extension extensions<>; rpc_gss3_extension extensions<>;
} rpc_gss3_create_res; } rpc_gss3_create_res;
The field "handle" is the RPCSEC_GSSv3 handle that the client will The field "handle" is the RPCSEC_GSSv3 handle that the client will
use on COPY requests involving the source and destination server. use on COPY requests involving the source and destination server.
The field granted_assertions[0].privs will be equal to The field granted_assertions[0].privs will be equal to
"copy_to_auth". The server will return a GSS_Wrap() of "copy_to_auth". The server will return a GSS_Wrap() of
copy_to_auth_priv. copy_to_auth_priv.
2.4.1.2.2. Starting a Secure Inter-Server Copy 3.4.1.2.2. Starting a Secure Inter-Server Copy
When the client sends a COPY_NOTIFY request to the source server, it When the client sends a COPY_NOTIFY request to the source server, it
uses the privileged "copy_from_auth" RPCSEC_GSSv3 handle. uses the privileged "copy_from_auth" RPCSEC_GSSv3 handle.
cna_destination_server in COPY_NOTIFY MUST be the same as the name of cna_destination_server in COPY_NOTIFY MUST be the same as the name of
the destination server specified in copy_from_auth_priv. Otherwise, the destination server specified in copy_from_auth_priv. Otherwise,
COPY_NOTIFY will fail with NFS4ERR_ACCESS. The source server COPY_NOTIFY will fail with NFS4ERR_ACCESS. The source server
verifies that the privilege <"copy_from_auth", user id, destination> verifies that the privilege <"copy_from_auth", user id, destination>
exists, and annotates it with the source filehandle, if the user exists, and annotates it with the source filehandle, if the user
principal has read access to the source file, and if administrative principal has read access to the source file, and if administrative
policies give the user principal and the NFS client read access to policies give the user principal and the NFS client read access to
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If the client sends a OFFLOAD_REVOKE to the source server to rescind If the client sends a OFFLOAD_REVOKE to the source server to rescind
the destination server's copy privilege, it uses the privileged the destination server's copy privilege, it uses the privileged
"copy_from_auth" RPCSEC_GSSv3 handle and the cra_destination_server "copy_from_auth" RPCSEC_GSSv3 handle and the cra_destination_server
in OFFLOAD_REVOKE MUST be the same as the name of the destination in OFFLOAD_REVOKE MUST be the same as the name of the destination
server specified in copy_from_auth_priv. The source server will then server specified in copy_from_auth_priv. The source server will then
delete the <"copy_from_auth", user id, destination> privilege and delete the <"copy_from_auth", user id, destination> privilege and
fail any subsequent copy requests sent under the auspices of this fail any subsequent copy requests sent under the auspices of this
privilege from the destination server. privilege from the destination server.
2.4.1.2.3. Securing ONC RPC Server-to-Server Copy Protocols 3.4.1.2.3. Securing ONC RPC Server-to-Server Copy Protocols
After a destination server has a "copy_to_auth" privilege established After a destination server has a "copy_to_auth" privilege established
on it, and it receives a COPY request, if it knows it will use an ONC on it, and it receives a COPY request, if it knows it will use an ONC
RPC protocol to copy data, it will establish a "copy_confirm_auth" RPC protocol to copy data, it will establish a "copy_confirm_auth"
privilege on the source server, using nfs@<destination> as the privilege on the source server, using nfs@<destination> as the
initiator principal, and nfs@<source> as the target principal. initiator principal, and nfs@<source> as the target principal.
The value of the field ccap_shared_secret_mic is a GSS_VerifyMIC() of The value of the field ccap_shared_secret_mic is a GSS_VerifyMIC() of
the shared secret passed in the copy_to_auth privilege. The field the shared secret passed in the copy_to_auth privilege. The field
ccap_username is the mapping of the user principal to an NFSv4 user ccap_username is the mapping of the user principal to an NFSv4 user
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policies can be overridden in case the destination server as-an- policies can be overridden in case the destination server as-an-
NFS-client is not authorized NFS-client is not authorized
o manual configuration to allow a copy relationship between the o manual configuration to allow a copy relationship between the
source and destination is not needed. source and destination is not needed.
If the attempt to establish a "copy_confirm_auth" privilege fails, If the attempt to establish a "copy_confirm_auth" privilege fails,
then when the user principal sends a COPY request to destination, the then when the user principal sends a COPY request to destination, the
destination server will reject it with NFS4ERR_PARTNER_NO_AUTH. destination server will reject it with NFS4ERR_PARTNER_NO_AUTH.
2.4.1.2.4. Securing Non ONC RPC Server-to-Server Copy Protocols 3.4.1.2.4. Securing Non ONC RPC Server-to-Server Copy Protocols
If the destination won't be using ONC RPC to copy the data, then the If the destination won't be using ONC RPC to copy the data, then the
source and destination are using an unspecified copy protocol. The source and destination are using an unspecified copy protocol. The
destination could use the shared secret and the NFSv4 user id to destination could use the shared secret and the NFSv4 user id to
prove to the source server that the user principal has authorized the prove to the source server that the user principal has authorized the
copy. copy.
For protocols that authenticate user names with passwords (e.g., HTTP For protocols that authenticate user names with passwords (e.g., HTTP
[12] and FTP [13]), the NFSv4 user id could be used as the user name, [12] and FTP [13]), the NFSv4 user id could be used as the user name,
and an ASCII hexadecimal representation of the RPCSEC_GSSv3 shared and an ASCII hexadecimal representation of the RPCSEC_GSSv3 shared
secret could be used as the user password or as input into non- secret could be used as the user password or as input into non-
password authentication methods like CHAP [14]. password authentication methods like CHAP [14].
2.4.1.3. Inter-Server Copy via ONC RPC but without RPCSEC_GSSv3 3.4.1.3. Inter-Server Copy via ONC RPC but without RPCSEC_GSSv3
ONC RPC security flavors other than RPCSEC_GSSv3 MAY be used with the ONC RPC security flavors other than RPCSEC_GSSv3 MAY be used with the
server-side copy offload operations described in this chapter. In server-side copy offload operations described in this chapter. In
particular, host-based ONC RPC security flavors such as AUTH_NONE and particular, host-based ONC RPC security flavors such as AUTH_NONE and
AUTH_SYS MAY be used. If a host-based security flavor is used, a AUTH_SYS MAY be used. If a host-based security flavor is used, a
minimal level of protection for the server-to-server copy protocol is minimal level of protection for the server-to-server copy protocol is
possible. possible.
In the absence of strong security mechanisms such as RPCSEC_GSSv3, In the absence of strong security mechanisms such as RPCSEC_GSSv3,
the challenge is how the source server and destination server the challenge is how the source server and destination server
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Provided that the random number is unpredictable and has been kept Provided that the random number is unpredictable and has been kept
secret by the parties involved, the source server will therefore know secret by the parties involved, the source server will therefore know
that these NFSv4.x operations are being issued by the destination that these NFSv4.x operations are being issued by the destination
server identified in the COPY_NOTIFY. This random number technique server identified in the COPY_NOTIFY. This random number technique
only provides initial authentication of the destination server, and only provides initial authentication of the destination server, and
cannot defend against man-in-the-middle attacks after authentication cannot defend against man-in-the-middle attacks after authentication
or an eavesdropper that observes the random number on the wire. or an eavesdropper that observes the random number on the wire.
Other secure communication techniques (e.g., IPsec) are necessary to Other secure communication techniques (e.g., IPsec) are necessary to
block these attacks. block these attacks.
2.4.1.4. Inter-Server Copy without ONC RPC and RPCSEC_GSSv3 3.4.1.4. Inter-Server Copy without ONC RPC and RPCSEC_GSSv3
The same techniques as Section 2.4.1.3, using unique URLs for each The same techniques as Section 3.4.1.3, using unique URLs for each
destination server, can be used for other protocols (e.g., HTTP [12] destination server, can be used for other protocols (e.g., HTTP [12]
and FTP [13]) as well. and FTP [13]) as well.
3. Support for Application IO Hints 4. Support for Application IO Hints
Applications can issue client I/O hints via posix_fadvise() [5] to Applications can issue client I/O hints via posix_fadvise() [5] to
the NFS client. While this can help the NFS client optimize I/O and the NFS client. While this can help the NFS client optimize I/O and
caching for a file, it does not allow the NFS server and its exported caching for a file, it does not allow the NFS server and its exported
file system to do likewise. We add an IO_ADVISE procedure file system to do likewise. We add an IO_ADVISE procedure
(Section 13.8) to communicate the client file access patterns to the (Section 14.8) to communicate the client file access patterns to the
NFS server. The NFS server upon receiving a IO_ADVISE operation MAY NFS server. The NFS server upon receiving a IO_ADVISE operation MAY
choose to alter its I/O and caching behavior, but is under no choose to alter its I/O and caching behavior, but is under no
obligation to do so. obligation to do so.
Application specific NFS clients such as those used by hypervisors Application specific NFS clients such as those used by hypervisors
and databases can also leverage application hints to communicate and databases can also leverage application hints to communicate
their specialized requirements. their specialized requirements.
4. Sparse Files 5. Sparse Files
4.1. Introduction 5.1. Introduction
A sparse file is a common way of representing a large file without A sparse file is a common way of representing a large file without
having to utilize all of the disk space for it. Consequently, a having to utilize all of the disk space for it. Consequently, a
sparse file uses less physical space than its size indicates. This sparse file uses less physical space than its size indicates. This
means the file contains 'holes', byte ranges within the file that means the file contains 'holes', byte ranges within the file that
contain no data. Most modern file systems support sparse files, contain no data. Most modern file systems support sparse files,
including most UNIX file systems and NTFS, but notably not Apple's including most UNIX file systems and NTFS, but notably not Apple's
HFS+. Common examples of sparse files include Virtual Machine (VM) HFS+. Common examples of sparse files include Virtual Machine (VM)
OS/disk images, database files, log files, and even checkpoint OS/disk images, database files, log files, and even checkpoint
recovery files most commonly used by the HPC community. recovery files most commonly used by the HPC community.
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the zeroes to be transferred. the zeroes to be transferred.
A sparse file is typically created by initializing the file to be all A sparse file is typically created by initializing the file to be all
zeros - nothing is written to the data in the file, instead the hole zeros - nothing is written to the data in the file, instead the hole
is recorded in the metadata for the file. So a 8G disk image might is recorded in the metadata for the file. So a 8G disk image might
be represented initially by a couple hundred bits in the inode and be represented initially by a couple hundred bits in the inode and
nothing on the disk. If the VM then writes 100M to a file in the nothing on the disk. If the VM then writes 100M to a file in the
middle of the image, there would now be two holes represented in the middle of the image, there would now be two holes represented in the
metadata and 100M in the data. metadata and 100M in the data.
Two new operations WRITE_PLUS (Section 13.7) and READ_PLUS Two new operations WRITE_PLUS (Section 14.7) and READ_PLUS
(Section 13.10) are introduced. WRITE_PLUS allows for the creation (Section 14.10) are introduced. WRITE_PLUS allows for the creation
of a sparse file and for hole punching. An application might want to of a sparse file and for hole punching. An application might want to
zero out a range of the file. READ_PLUS supports all the features of zero out a range of the file. READ_PLUS supports all the features of
READ but includes an extension to support sparse pattern files READ but includes an extension to support sparse pattern files
(Section 6.1.2). READ_PLUS is guaranteed to perform no worse than (Section 7.1.2). READ_PLUS is guaranteed to perform no worse than
READ, and can dramatically improve performance with sparse files. READ, and can dramatically improve performance with sparse files.
READ_PLUS does not depend on pNFS protocol features, but can be used READ_PLUS does not depend on pNFS protocol features, but can be used
by pNFS to support sparse files. by pNFS to support sparse files.
4.2. Terminology 5.2. Terminology
Regular file: An object of file type NF4REG or NF4NAMEDATTR. Regular file: An object of file type NF4REG or NF4NAMEDATTR.
Sparse file: A Regular file that contains one or more Holes. Sparse file: A Regular file that contains one or more Holes.
Hole: A byte range within a Sparse file that contains regions of all Hole: A byte range within a Sparse file that contains regions of all
zeroes. For block-based file systems, this could also be an zeroes. For block-based file systems, this could also be an
unallocated region of the file. unallocated region of the file.
Hole Threshold: The minimum length of a Hole as determined by the Hole Threshold: The minimum length of a Hole as determined by the
server. If a server chooses to define a Hole Threshold, then it server. If a server chooses to define a Hole Threshold, then it
would not return hole information about holes with a length would not return hole information about holes with a length
shorter than the Hole Threshold. shorter than the Hole Threshold.
4.3. New Operations 5.3. New Operations
READ_PLUS and WRITE_PLUS are new variants of the NFSv4.1 READ and READ_PLUS and WRITE_PLUS are new variants of the NFSv4.1 READ and
WRITE operations [1]. Besides being able to support all of the data WRITE operations [1]. Besides being able to support all of the data
semantics of those operations, they can also be used by the client semantics of those operations, they can also be used by the client
and server to efficiently transfer both holes and ADHs (see and server to efficiently transfer both holes and ADHs (see
Section 6.1.1). As both READ and WRITE are inefficient for transfer Section 7.1.1). As both READ and WRITE are inefficient for transfer
of sparse sections of the file, they are marked as OBSOLETE in of sparse sections of the file, they are marked as END-OF-LIFE in
NFSv4.2. Instead, a client should utilize READ_PLUS and WRITE_PLUS. NFSv4.2. Instead, a client should utilize READ_PLUS and WRITE_PLUS.
Note that as the client has no a priori knowledge of whether either Note that as the client has no a priori knowledge of whether either
an ADH or a hole is present or not, if it supports these operations an ADH or a hole is present or not, if it supports these operations
and so does the server, then it should always use these operations. and so does the server, then it should always use these operations.
4.3.1. READ_PLUS 5.3.1. READ_PLUS
For holes, READ_PLUS extends the response to avoid returning data for For holes, READ_PLUS extends the response to avoid returning data for
portions of the file which are either initialized and contain no portions of the file which are either initialized and contain no
backing store or if the result would appear to be so. I.e., if the backing store or if the result would appear to be so. I.e., if the
result was a data block composed entirely of zeros, then it is easier result was a data block composed entirely of zeros, then it is easier
to return a hole. Returning data blocks of uninitialized data wastes to return a hole. Returning data blocks of uninitialized data wastes
computational and network resources, thus reducing performance. For computational and network resources, thus reducing performance. For
ADHs, READ_PLUS is used to return the metadata describing the ADHs, READ_PLUS is used to return the metadata describing the
portions of the file which are either initialized and contain no portions of the file which are either initialized and contain no
backing store. backing store.
If the client sends a READ operation, it is explicitly stating that If the client sends a READ operation, it is explicitly stating that
it is neither supporting sparse files nor ADHs. So if a READ occurs it is neither supporting sparse files nor ADHs. So if a READ occurs
on a sparse ADH or file, then the server must expand such data to be on a sparse ADH or file, then the server must expand such data to be
raw bytes. If a READ occurs in the middle of a hole or ADH, the raw bytes. If a READ occurs in the middle of a hole or ADH, the
server can only send back bytes starting from that offset. In server can only send back bytes starting from that offset. In
contrast, if a READ_PLUS occurs in the middle of a hole or ADH, the contrast, if a READ_PLUS occurs in the middle of a hole or ADH, the
server can send back a range which starts before the offset and server can send back a range which starts before the offset and
extends past the range. extends past the range.
4.3.2. WRITE_PLUS 5.3.2. WRITE_PLUS
WRITE_PLUS can be used to either hole punch or initialize ADHs. For WRITE_PLUS can be used to either hole punch or initialize ADHs. For
either purpose, the client can avoid the transfer of a repetitive either purpose, the client can avoid the transfer of a repetitive
pattern across the network. If the filesystem on the server does not pattern across the network. If the filesystem on the server does not
supports sparse files, the WRITE_PLUS operation may return the result supports sparse files, the WRITE_PLUS operation may return the result
asynchronously via the CB_OFFLOAD operation. As a hole punch may asynchronously via the CB_OFFLOAD operation. As a hole punch may
entail deallocating data blocks, even if the filesystem supports entail deallocating data blocks, even if the filesystem supports
sparse files, it may still have to return the result via CB_OFFLOAD. sparse files, it may still have to return the result via CB_OFFLOAD.
5. Space Reservation 6. Space Reservation
5.1. Introduction 6.1. Introduction
Applications such as hypervisors want to be able to reserve space for Applications such as hypervisors want to be able to reserve space for
a file, report the amount of actual disk space a file occupies, and a file, report the amount of actual disk space a file occupies, and
freeup the backing space of a file when it is not required. In freeup the backing space of a file when it is not required. In
virtualized environments, virtual disk files are often stored on NFS virtualized environments, virtual disk files are often stored on NFS
mounted volumes. Since virtual disk files represent the hard disks mounted volumes. Since virtual disk files represent the hard disks
of virtual machines, hypervisors often have to guarantee certain of virtual machines, hypervisors often have to guarantee certain
properties for the file. properties for the file.
One such example is space reservation. When a hypervisor creates a One such example is space reservation. When a hypervisor creates a
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Currently, in order to achieve such a guarantee, applications zero Currently, in order to achieve such a guarantee, applications zero
the entire file. The initial zeroing allocates the backing blocks the entire file. The initial zeroing allocates the backing blocks
and all subsequent writes are overwrites of already allocated blocks. and all subsequent writes are overwrites of already allocated blocks.
This approach is not only inefficient in terms of the amount of I/O This approach is not only inefficient in terms of the amount of I/O
done, it is also not guaranteed to work on file systems that are log done, it is also not guaranteed to work on file systems that are log
structured or deduplicated. An efficient way of guaranteeing space structured or deduplicated. An efficient way of guaranteeing space
reservation would be beneficial to such applications. reservation would be beneficial to such applications.
We define a "reservation" as being the combination of the We define a "reservation" as being the combination of the
space_reserved attribute (see Section 11.2.4) and the size attribute space_reserved attribute (see Section 12.2.4) and the size attribute
(see Section 5.8.1.5 of [1]). If space_reserved attribute is set on (see Section 5.8.1.5 of [1]). If space_reserved attribute is set on
a file, it is guaranteed that writes that do not grow the file past a file, it is guaranteed that writes that do not grow the file past
the size will not fail with NFS4ERR_NOSPC. Once the size is changed, the size will not fail with NFS4ERR_NOSPC. Once the size is changed,
then the reservation is changed to that new size. then the reservation is changed to that new size.
Another useful feature is the ability to report the number of blocks Another useful feature is the ability to report the number of blocks
that would be freed when a file is deleted. Currently, NFS reports that would be freed when a file is deleted. Currently, NFS reports
two size attributes: two size attributes:
size The logical file size of the file. size The logical file size of the file.
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reporting of the space utilization. reporting of the space utilization.
For example, two files A and B have 10 blocks each. Let 6 of these For example, two files A and B have 10 blocks each. Let 6 of these
blocks be shared between them. Thus, the combined space utilized by blocks be shared between them. Thus, the combined space utilized by
the two files is 14 * BLOCK_SIZE bytes. In the former case, the the two files is 14 * BLOCK_SIZE bytes. In the former case, the
combined space utilization of the two files would be reported as 20 * combined space utilization of the two files would be reported as 20 *
BLOCK_SIZE. However, deleting either would only result in 4 * BLOCK_SIZE. However, deleting either would only result in 4 *
BLOCK_SIZE being freed. Conversely, the latter interpretation would BLOCK_SIZE being freed. Conversely, the latter interpretation would
report that the space utilization is only 8 * BLOCK_SIZE. report that the space utilization is only 8 * BLOCK_SIZE.
Adding another size attribute, space_freed (see Section 11.2.5), is Adding another size attribute, space_freed (see Section 12.2.5), is
helpful in solving this problem. space_freed is the number of blocks helpful in solving this problem. space_freed is the number of blocks
that are allocated to the given file that would be freed on its that are allocated to the given file that would be freed on its
deletion. In the example, both A and B would report space_freed as 4 deletion. In the example, both A and B would report space_freed as 4
* BLOCK_SIZE and space_used as 10 * BLOCK_SIZE. If A is deleted, B * BLOCK_SIZE and space_used as 10 * BLOCK_SIZE. If A is deleted, B
will report space_freed as 10 * BLOCK_SIZE as the deletion of B would will report space_freed as 10 * BLOCK_SIZE as the deletion of B would
result in the deallocation of all 10 blocks. result in the deallocation of all 10 blocks.
The addition of this problem does not solve the problem of space The addition of this problem does not solve the problem of space
being over-reported. However, over-reporting is better than under- being over-reported. However, over-reporting is better than under-
reporting. reporting.
6. Application Data Hole Support 7. Application Data Hole Support
At the OS level, files are contained on disk blocks. Applications At the OS level, files are contained on disk blocks. Applications
are also free to impose structure on the data contained in a file and are also free to impose structure on the data contained in a file and
we can define an Application Data Block (ADB) to be such a structure. we can define an Application Data Block (ADB) to be such a structure.
From the application's viewpoint, it only wants to handle ADBs and From the application's viewpoint, it only wants to handle ADBs and
not raw bytes (see [15]). An ADB is typically comprised of two not raw bytes (see [15]). An ADB is typically comprised of two
sections: a header and data. The header describes the sections: a header and data. The header describes the
characteristics of the block and can provide a means to detect characteristics of the block and can provide a means to detect
corruption in the data payload. The data section is typically corruption in the data payload. The data section is typically
initialized to all zeros. initialized to all zeros.
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In this section, we are going to define an Application Data Hole In this section, we are going to define an Application Data Hole
(ADH), which is a generic framework for transferring the ADB, present (ADH), which is a generic framework for transferring the ADB, present
one approach to detecting corruption in a given ADH implementation, one approach to detecting corruption in a given ADH implementation,
and describe the model for how the client and server can support and describe the model for how the client and server can support
efficient initialization of ADHs, reading of ADH holes, punching ADH efficient initialization of ADHs, reading of ADH holes, punching ADH
holes in a file, and space reservation. We define the ADHN to be the holes in a file, and space reservation. We define the ADHN to be the
Application Data Hole Number, which is the logical block number Application Data Hole Number, which is the logical block number
discussed earlier. discussed earlier.
6.1. Generic Framework 7.1. Generic Framework
We want the representation of the ADH to be flexible enough to We want the representation of the ADH to be flexible enough to
support many different applications. The most basic approach is no support many different applications. The most basic approach is no
imposition of a block at all, which means we are working with the raw imposition of a block at all, which means we are working with the raw
bytes. Such an approach would be useful for storing holes, punching bytes. Such an approach would be useful for storing holes, punching
holes, etc. In more complex deployments, a server might be holes, etc. In more complex deployments, a server might be
supporting multiple applications, each with their own definition of supporting multiple applications, each with their own definition of
the ADH. One might store the ADHN at the start of the block and then the ADH. One might store the ADHN at the start of the block and then
have a guard pattern to detect corruption [17]. The next might store have a guard pattern to detect corruption [17]. The next might store
the ADHN at an offset of 100 bytes within the block and have no guard the ADHN at an offset of 100 bytes within the block and have no guard
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defined formats for their data blocks. defined formats for their data blocks.
The guard pattern can be used to represent the state of the block, to The guard pattern can be used to represent the state of the block, to
protect against corruption, or both. Again, it needs to be able to protect against corruption, or both. Again, it needs to be able to
be placed anywhere within the ADH. be placed anywhere within the ADH.
We need to be able to represent the starting offset of the block and We need to be able to represent the starting offset of the block and
the size of the block. Note that nothing prevents the application the size of the block. Note that nothing prevents the application
from defining different sized blocks in a file. from defining different sized blocks in a file.
6.1.1. Data Hole Representation 7.1.1. Data Hole Representation
struct app_data_hole4 { struct app_data_hole4 {
offset4 adh_offset; offset4 adh_offset;
length4 adh_block_size; length4 adh_block_size;
length4 adh_block_count; length4 adh_block_count;
length4 adh_reloff_blocknum; length4 adh_reloff_blocknum;
count4 adh_block_num; count4 adh_block_num;
length4 adh_reloff_pattern; length4 adh_reloff_pattern;
opaque adh_pattern<>; opaque adh_pattern<>;
}; };
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The app_data_hole4 structure captures the abstraction presented for The app_data_hole4 structure captures the abstraction presented for
the ADH. The additional fields present are to allow the transmission the ADH. The additional fields present are to allow the transmission
of adh_block_count ADHs at one time. We also use adh_block_num to of adh_block_count ADHs at one time. We also use adh_block_num to
convey the ADHN of the first block in the sequence. Each ADH will convey the ADHN of the first block in the sequence. Each ADH will
contain the same adh_pattern string. contain the same adh_pattern string.
As both adh_block_num and adh_pattern are optional, if either As both adh_block_num and adh_pattern are optional, if either
adh_reloff_pattern or adh_reloff_blocknum is set to NFS4_UINT64_MAX, adh_reloff_pattern or adh_reloff_blocknum is set to NFS4_UINT64_MAX,
then the corresponding field is not set in any of the ADH. then the corresponding field is not set in any of the ADH.
6.1.2. Data Content 7.1.2. Data Content
/* /*
* Use an enum such that we can extend new types. * Use an enum such that we can extend new types.
*/ */
enum data_content4 { enum data_content4 {
NFS4_CONTENT_DATA = 0, NFS4_CONTENT_DATA = 0,
NFS4_CONTENT_APP_DATA_HOLE = 1, NFS4_CONTENT_APP_DATA_HOLE = 1,
NFS4_CONTENT_HOLE = 2 NFS4_CONTENT_HOLE = 2
}; };
New operations might need to differentiate between wanting to access New operations might need to differentiate between wanting to access
data versus an ADH. Also, future minor versions might want to data versus an ADH. Also, future minor versions might want to
introduce new data formats. This enumeration allows that to occur. introduce new data formats. This enumeration allows that to occur.
6.2. An Example of Detecting Corruption 7.2. An Example of Detecting Corruption
In this section, we define an ADH format in which corruption can be In this section, we define an ADH format in which corruption can be
detected. Note that this is just one possible format and means to detected. Note that this is just one possible format and means to
detect corruption. detect corruption.
Consider a very basic implementation of an operating system's disk Consider a very basic implementation of an operating system's disk
blocks. A block is either data or it is an indirect block which blocks. A block is either data or it is an indirect block which
allows for files to be larger than one block. It is desired to be allows for files to be larger than one block. It is desired to be
able to initialize a block. Lastly, to quickly unlink a file, a able to initialize a block. Lastly, to quickly unlink a file, a
block can be marked invalid. The contents remain intact - which block can be marked invalid. The contents remain intact - which
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minimum amount of data we incorporated into our generic framework. minimum amount of data we incorporated into our generic framework.
I.e., the guard pattern is sufficient in allowing applications to I.e., the guard pattern is sufficient in allowing applications to
design their own corruption detection. design their own corruption detection.
Finally, it is important to note that none of these corruption checks Finally, it is important to note that none of these corruption checks
occur in the transport layer. The server and client components are occur in the transport layer. The server and client components are
totally unaware of the file format and might report everything as totally unaware of the file format and might report everything as
being transferred correctly even in the case the application detects being transferred correctly even in the case the application detects
corruption. corruption.
6.3. Example of READ_PLUS 7.3. Example of READ_PLUS
The hypothetical application presented in Section 6.2 can be used to The hypothetical application presented in Section 7.2 can be used to
illustrate how READ_PLUS would return an array of results. A file is illustrate how READ_PLUS would return an array of results. A file is
created and initialized with 100 4k ADHs in the FREE state: created and initialized with 100 4k ADHs in the FREE state:
WRITE_PLUS {0, 4k, 100, 0, 0, 8, 0xfeedface} WRITE_PLUS {0, 4k, 100, 0, 0, 8, 0xfeedface}
Further, assume the application writes a single ADH at 16k, changing Further, assume the application writes a single ADH at 16k, changing
the guard pattern to 0xcafedead, we would then have in memory: the guard pattern to 0xcafedead, we would then have in memory:
0 -> (16k - 1) : 4k, 4, 0, 0, 8, 0xfeedface 0 -> (16k - 1) : 4k, 4, 0, 0, 8, 0xfeedface
16k -> (20k - 1) : 00 00 00 05 ca fe de ad XX XX ... XX XX 16k -> (20k - 1) : 00 00 00 05 ca fe de ad XX XX ... XX XX
20k -> 400k : 4k, 95, 0, 6, 0xfeedface 20k -> 400k : 4k, 95, 0, 6, 0xfeedface
And when the client did a READ_PLUS of 64k at the start of the file, And when the client did a READ_PLUS of 64k at the start of the file,
it would get back a result of an ADH, some data, and a final ADH: it would get back a result of an ADH, some data, and a final ADH:
ADH {0, 4, 0, 0, 8, 0xfeedface} ADH {0, 4, 0, 0, 8, 0xfeedface}
data 4k data 4k
ADH {20k, 4k, 59, 0, 6, 0xfeedface} ADH {20k, 4k, 59, 0, 6, 0xfeedface}
7. Labeled NFS 8. Labeled NFS
7.1. Introduction 8.1. Introduction
Access control models such as Unix permissions or Access Control Access control models such as Unix permissions or Access Control
Lists are commonly referred to as Discretionary Access Control (DAC) Lists are commonly referred to as Discretionary Access Control (DAC)
models. These systems base their access decisions on user identity models. These systems base their access decisions on user identity
and resource ownership. In contrast Mandatory Access Control (MAC) and resource ownership. In contrast Mandatory Access Control (MAC)
models base their access control decisions on the label on the models base their access control decisions on the label on the
subject (usually a process) and the object it wishes to access [19]. subject (usually a process) and the object it wishes to access [19].
These labels may contain user identity information but usually These labels may contain user identity information but usually
contain additional information. In DAC systems users are free to contain additional information. In DAC systems users are free to
specify the access rules for resources that they own. MAC models specify the access rules for resources that they own. MAC models
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NFSv4 in the form of a new version of the RPCSEC_GSS [6] framework. NFSv4 in the form of a new version of the RPCSEC_GSS [6] framework.
In order for an NFSv4 server to apply MAC checks it must obtain In order for an NFSv4 server to apply MAC checks it must obtain
additional information from the client. Several methods were additional information from the client. Several methods were
explored for performing this and it was decided that the best explored for performing this and it was decided that the best
approach was to incorporate the ability to make security attribute approach was to incorporate the ability to make security attribute
assertions through the RPC mechanism. RPCSECGSSv3 [4] outlines a assertions through the RPC mechanism. RPCSECGSSv3 [4] outlines a
method to assert additional security information such as security method to assert additional security information such as security
labels on gss context creation and have that data bound to all RPC labels on gss context creation and have that data bound to all RPC
requests that make use of that context. requests that make use of that context.
7.2. Definitions 8.2. Definitions
Label Format Specifier (LFS): is an identifier used by the client to Label Format Specifier (LFS): is an identifier used by the client to
establish the syntactic format of the security label and the establish the syntactic format of the security label and the
semantic meaning of its components. These specifiers exist in a semantic meaning of its components. These specifiers exist in a
registry associated with documents describing the format and registry associated with documents describing the format and
semantics of the label. semantics of the label.
Label Format Registry: is the IANA registry containing all Label Format Registry: is the IANA registry containing all
registered LFS along with references to the documents that registered LFS along with references to the documents that
describe the syntactic format and semantics of the security label. describe the syntactic format and semantics of the security label.
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MAC-Aware: is a server which can transmit and store object labels. MAC-Aware: is a server which can transmit and store object labels.
MAC-Functional: is a client or server which is Labeled NFS enabled. MAC-Functional: is a client or server which is Labeled NFS enabled.
Such a system can interpret labels and apply policies based on the Such a system can interpret labels and apply policies based on the
security system. security system.
Multi-Level Security (MLS): is a traditional model where objects are Multi-Level Security (MLS): is a traditional model where objects are
given a sensitivity level (Unclassified, Secret, Top Secret, etc) given a sensitivity level (Unclassified, Secret, Top Secret, etc)
and a category set [20]. and a category set [20].
7.3. MAC Security Attribute 8.3. MAC Security Attribute
MAC models base access decisions on security attributes bound to MAC models base access decisions on security attributes bound to
subjects and objects. This information can range from a user subjects and objects. This information can range from a user
identity for an identity based MAC model, sensitivity levels for identity for an identity based MAC model, sensitivity levels for
Multi-level security, or a type for Type Enforcement. These models Multi-level security, or a type for Type Enforcement. These models
base their decisions on different criteria but the semantics of the base their decisions on different criteria but the semantics of the
security attribute remain the same. The semantics required by the security attribute remain the same. The semantics required by the
security attributes are listed below: security attributes are listed below:
o MUST provide flexibility with respect to the MAC model. o MUST provide flexibility with respect to the MAC model.
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between MAC mechanisms. The second component is an opaque field between MAC mechanisms. The second component is an opaque field
which is the actual security attribute data. To allow for various which is the actual security attribute data. To allow for various
MAC models, NFSv4 should be used solely as a transport mechanism for MAC models, NFSv4 should be used solely as a transport mechanism for
the security attribute. It is the responsibility of the endpoints to the security attribute. It is the responsibility of the endpoints to
consume the security attribute and make access decisions based on consume the security attribute and make access decisions based on
their respective models. In addition, creation of objects through their respective models. In addition, creation of objects through
OPEN and CREATE allows for the security attribute to be specified OPEN and CREATE allows for the security attribute to be specified
upon creation. By providing an atomic create and set operation for upon creation. By providing an atomic create and set operation for
the security attribute it is possible to enforce the second and the security attribute it is possible to enforce the second and
fourth requirements. The recommended attribute FATTR4_SEC_LABEL (see fourth requirements. The recommended attribute FATTR4_SEC_LABEL (see
Section 11.2.2) will be used to satisfy this requirement. Section 12.2.2) will be used to satisfy this requirement.
7.3.1. Delegations 8.3.1. Delegations
In the event that a security attribute is changed on the server while In the event that a security attribute is changed on the server while
a client holds a delegation on the file, both the server and the a client holds a delegation on the file, both the server and the
client MUST follow the NFSv4.1 protocol (see Chapter 10 of [1]) with client MUST follow the NFSv4.1 protocol (see Chapter 10 of [1]) with
respect to attribute changes. It SHOULD flush all changes back to respect to attribute changes. It SHOULD flush all changes back to
the server and relinquish the delegation. the server and relinquish the delegation.
7.3.2. Permission Checking 8.3.2. Permission Checking
It is not feasible to enumerate all possible MAC models and even It is not feasible to enumerate all possible MAC models and even
levels of protection within a subset of these models. This means levels of protection within a subset of these models. This means
that the NFSv4 client and servers cannot be expected to directly make that the NFSv4 client and servers cannot be expected to directly make
access control decisions based on the security attribute. Instead access control decisions based on the security attribute. Instead
NFSv4 should defer permission checking on this attribute to the host NFSv4 should defer permission checking on this attribute to the host
system. These checks are performed in addition to existing DAC and system. These checks are performed in addition to existing DAC and
ACL checks outlined in the NFSv4 protocol. Section 7.6 gives a ACL checks outlined in the NFSv4 protocol. Section 8.6 gives a
specific example of how the security attribute is handled under a specific example of how the security attribute is handled under a
particular MAC model. particular MAC model.
7.3.3. Object Creation 8.3.3. Object Creation
When creating files in NFSv4 the OPEN and CREATE operations are used. When creating files in NFSv4 the OPEN and CREATE operations are used.
One of the parameters to these operations is an fattr4 structure One of the parameters to these operations is an fattr4 structure
containing the attributes the file is to be created with. This containing the attributes the file is to be created with. This
allows NFSv4 to atomically set the security attribute of files upon allows NFSv4 to atomically set the security attribute of files upon
creation. When a client is MAC-Functional it must always provide the creation. When a client is MAC-Functional it must always provide the
initial security attribute upon file creation. In the event that the initial security attribute upon file creation. In the event that the
server is MAC-Functional as well, it should determine by policy server is MAC-Functional as well, it should determine by policy
whether it will accept the attribute from the client or instead make whether it will accept the attribute from the client or instead make
the determination itself. If the client is not MAC-Functional, then the determination itself. If the client is not MAC-Functional, then
the MAC-Functional server must decide on a default label. A more in the MAC-Functional server must decide on a default label. A more in
depth explanation can be found in Section 7.6. depth explanation can be found in Section 8.6.
7.3.4. Existing Objects 8.3.4. Existing Objects
Note that under the MAC model, all objects must have labels. Note that under the MAC model, all objects must have labels.
Therefore, if an existing server is upgraded to include Labeled NFS Therefore, if an existing server is upgraded to include Labeled NFS
support, then it is the responsibility of the security system to support, then it is the responsibility of the security system to
define the behavior for existing objects. define the behavior for existing objects.
7.3.5. Label Changes 8.3.5. Label Changes
If there are open delegations on the file belonging to client other If there are open delegations on the file belonging to client other
than the one making the label change, then the process described in than the one making the label change, then the process described in
Section 7.3.1 must be followed. In short, the delegation will be Section 8.3.1 must be followed. In short, the delegation will be
recalled, which effectively notifies the client of the change. recalled, which effectively notifies the client of the change.
As the server is always presented with the subject label from the As the server is always presented with the subject label from the
client, it does not necessarily need to communicate the fact that the client, it does not necessarily need to communicate the fact that the
label has changed to the client. In the cases where the change label has changed to the client. In the cases where the change
outright denies the client access, the client will be able to quickly outright denies the client access, the client will be able to quickly
determine that there is a new label in effect. determine that there is a new label in effect.
Consider a system in which the clients enforce MAC checks and and the Consider a system in which the clients enforce MAC checks and and the
server has a very simple security system which just stores the server has a very simple security system which just stores the
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The way in which MAC labels are enforced is by the client. The The way in which MAC labels are enforced is by the client. The
security policies on the client can be such that the client does not security policies on the client can be such that the client does not
have access to the file unless it has a delegation. The recall of have access to the file unless it has a delegation. The recall of
the delegation will force the client to flush any cached content of the delegation will force the client to flush any cached content of
the file. The clients could also be configured to periodically the file. The clients could also be configured to periodically
VERIFY/NVERIFY the FATTR4_CHANGE_SEC_LABEL attribute to determine VERIFY/NVERIFY the FATTR4_CHANGE_SEC_LABEL attribute to determine
when the label has changed. When a change is detected, then the when the label has changed. When a change is detected, then the
client could take the costlier action of retrieving the client could take the costlier action of retrieving the
FATTR4_SEC_LABEL. FATTR4_SEC_LABEL.
7.4. pNFS Considerations 8.4. pNFS Considerations
This section examines the issues in deploying Labeled NFS in a pNFS This section examines the issues in deploying Labeled NFS in a pNFS
community of servers. community of servers.
7.4.1. MAC Label Checks 8.4.1. MAC Label Checks
The new FATTR4_SEC_LABEL attribute is metadata information and as The new FATTR4_SEC_LABEL attribute is metadata information and as
such the DS is not aware of the value contained on the MDS. such the DS is not aware of the value contained on the MDS.
Fortunately, the NFSv4.1 protocol [1] already has provisions for Fortunately, the NFSv4.1 protocol [1] already has provisions for
doing access level checks from the DS to the MDS. In order for the doing access level checks from the DS to the MDS. In order for the
DS to validate the subject label presented by the client, it SHOULD DS to validate the subject label presented by the client, it SHOULD
utilize this mechanism. utilize this mechanism.
7.5. Discovery of Server Labeled NFS Support 8.5. Discovery of Server Labeled NFS Support
The server can easily determine that a client supports Labeled NFS The server can easily determine that a client supports Labeled NFS
when it queries for the FATTR4_SEC_LABEL label for an object. Note when it queries for the FATTR4_SEC_LABEL label for an object. Note
that it cannot assume that the presence of RPCSEC_GSSv3 indicates that it cannot assume that the presence of RPCSEC_GSSv3 indicates
Labeled NFS support. The client might need to discover which LFS the Labeled NFS support. The client might need to discover which LFS the
server supports. server supports.
A server which supports Labeled NFS MUST allow a client with any A server which supports Labeled NFS MUST allow a client with any
subject label to retrieve the FATTR4_SEC_LABEL attribute for the root subject label to retrieve the FATTR4_SEC_LABEL attribute for the root
filehandle, ROOTFH. The following compound must always succeed as filehandle, ROOTFH. The following compound must always succeed as
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PUTROOTFH, GETATTR {FATTR4_SEC_LABEL} PUTROOTFH, GETATTR {FATTR4_SEC_LABEL}
Note that the server might have imposed a security flavor on the root Note that the server might have imposed a security flavor on the root
that precludes such access. I.e., if the server requires kerberized that precludes such access. I.e., if the server requires kerberized
access and the client presents a compound with AUTH_SYS, then the access and the client presents a compound with AUTH_SYS, then the
server is allowed to return NFS4ERR_WRONGSEC in this case. But if server is allowed to return NFS4ERR_WRONGSEC in this case. But if
the client presents a correct security flavor, then the server MUST the client presents a correct security flavor, then the server MUST
return the FATTR4_SEC_LABEL attribute with the supported LFS filled return the FATTR4_SEC_LABEL attribute with the supported LFS filled
in. in.
7.6. MAC Security NFS Modes of Operation 8.6. MAC Security NFS Modes of Operation
A system using Labeled NFS may operate in two modes. The first mode A system using Labeled NFS may operate in two modes. The first mode
provides the most protection and is called "full mode". In this mode provides the most protection and is called "full mode". In this mode
both the client and server implement a MAC model allowing each end to both the client and server implement a MAC model allowing each end to
make an access control decision. The remaining mode is called the make an access control decision. The remaining mode is called the
"guest mode" and in this mode one end of the connection is not "guest mode" and in this mode one end of the connection is not
implementing a MAC model and thus offers less protection than full implementing a MAC model and thus offers less protection than full
mode. mode.
7.6.1. Full Mode 8.6.1. Full Mode
Full mode environments consist of MAC-Functional NFSv4 servers and Full mode environments consist of MAC-Functional NFSv4 servers and
clients and may be composed of mixed MAC models and policies. The clients and may be composed of mixed MAC models and policies. The
system requires that both the client and server have an opportunity system requires that both the client and server have an opportunity
to perform an access control check based on all relevant information to perform an access control check based on all relevant information
within the network. The file object security attribute is provided within the network. The file object security attribute is provided
using the mechanism described in Section 7.3. The security attribute using the mechanism described in Section 8.3. The security attribute
of the subject making the request is transported at the RPC layer of the subject making the request is transported at the RPC layer
using the mechanism described in RPCSECGSSv3 [4]. using the mechanism described in RPCSECGSSv3 [4].
7.6.1.1. Initial Labeling and Translation 8.6.1.1. Initial Labeling and Translation
The ability to create a file is an action that a MAC model may wish The ability to create a file is an action that a MAC model may wish
to mediate. The client is given the responsibility to determine the to mediate. The client is given the responsibility to determine the
initial security attribute to be placed on a file. This allows the initial security attribute to be placed on a file. This allows the
client to make a decision as to the acceptable security attributes to client to make a decision as to the acceptable security attributes to
create a file with before sending the request to the server. Once create a file with before sending the request to the server. Once
the server receives the creation request from the client it may the server receives the creation request from the client it may
choose to evaluate if the security attribute is acceptable. choose to evaluate if the security attribute is acceptable.
Security attributes on the client and server may vary based on MAC Security attributes on the client and server may vary based on MAC
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identify the format and meaning of the opaque portion of the security identify the format and meaning of the opaque portion of the security
attribute. A full mode environment may contain hosts operating in attribute. A full mode environment may contain hosts operating in
several different LFSs. In this case a mechanism for translating the several different LFSs. In this case a mechanism for translating the
opaque portion of the security attribute is needed. The actual opaque portion of the security attribute is needed. The actual
translation function will vary based on MAC model and policy and is translation function will vary based on MAC model and policy and is
out of the scope of this document. If a translation is unavailable out of the scope of this document. If a translation is unavailable
for a given LFS then the request MUST be denied. Another recourse is for a given LFS then the request MUST be denied. Another recourse is
to allow the host to provide a fallback mapping for unknown security to allow the host to provide a fallback mapping for unknown security
attributes. attributes.
7.6.1.2. Policy Enforcement 8.6.1.2. Policy Enforcement
In full mode access control decisions are made by both the clients In full mode access control decisions are made by both the clients
and servers. When a client makes a request it takes the security and servers. When a client makes a request it takes the security
attribute from the requesting process and makes an access control attribute from the requesting process and makes an access control
decision based on that attribute and the security attribute of the decision based on that attribute and the security attribute of the
object it is trying to access. If the client denies that access an object it is trying to access. If the client denies that access an
RPC call to the server is never made. If however the access is RPC call to the server is never made. If however the access is
allowed the client will make a call to the NFS server. allowed the client will make a call to the NFS server.
When the server receives the request from the client it extracts the When the server receives the request from the client it extracts the
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trying to access to make an access control decision. If the server's trying to access to make an access control decision. If the server's
policy allows this access it will fulfill the client's request, policy allows this access it will fulfill the client's request,
otherwise it will return NFS4ERR_ACCESS. otherwise it will return NFS4ERR_ACCESS.
Implementations MAY validate security attributes supplied over the Implementations MAY validate security attributes supplied over the
network to ensure that they are within a set of attributes permitted network to ensure that they are within a set of attributes permitted
from a specific peer, and if not, reject them. Note that a system from a specific peer, and if not, reject them. Note that a system
may permit a different set of attributes to be accepted from each may permit a different set of attributes to be accepted from each
peer. peer.
7.6.1.3. Limited Server 8.6.1.3. Limited Server
A Limited Server mode (see Section 3.5.2 of [19]) consists of a A Limited Server mode (see Section 3.5.2 of [19]) consists of a
server which is label aware, but does not enforce policies. Such a server which is label aware, but does not enforce policies. Such a
server will store and retrieve all object labels presented by server will store and retrieve all object labels presented by
clients, utilize the methods described in Section 7.3.5 to allow the clients, utilize the methods described in Section 8.3.5 to allow the
clients to detect changing labels,, but will not restrict access via clients to detect changing labels,, but will not restrict access via
the subject label. Instead, it will expect the clients to enforce the subject label. Instead, it will expect the clients to enforce
all such access locally. all such access locally.
7.6.2. Guest Mode 8.6.2. Guest Mode
Guest mode implies that either the client or the server does not Guest mode implies that either the client or the server does not
handle labels. If the client is not Labeled NFS aware, then it will handle labels. If the client is not Labeled NFS aware, then it will
not offer subject labels to the server. The server is the only not offer subject labels to the server. The server is the only
entity enforcing policy, and may selectively provide standard NFS entity enforcing policy, and may selectively provide standard NFS
services to clients based on their authentication credentials and/or services to clients based on their authentication credentials and/or
associated network attributes (e.g., IP address, network interface). associated network attributes (e.g., IP address, network interface).
The level of trust and access extended to a client in this mode is The level of trust and access extended to a client in this mode is
configuration-specific. If the server is not Labeled NFS aware, then configuration-specific. If the server is not Labeled NFS aware, then
it will not return object labels to the client. Clients in this it will not return object labels to the client. Clients in this
environment are may consist of groups implementing different MAC environment are may consist of groups implementing different MAC
model policies. The system requires that all clients in the model policies. The system requires that all clients in the
environment be responsible for access control checks. environment be responsible for access control checks.
7.7. Security Considerations 8.7. Security Considerations
This entire chapter deals with security issues. This entire chapter deals with security issues.
Depending on the level of protection the MAC system offers there may Depending on the level of protection the MAC system offers there may
be a requirement to tightly bind the security attribute to the data. be a requirement to tightly bind the security attribute to the data.
When only one of the client or server enforces labels, it is When only one of the client or server enforces labels, it is
important to realize that the other side is not enforcing MAC important to realize that the other side is not enforcing MAC
protections. Alternate methods might be in use to handle the lack of protections. Alternate methods might be in use to handle the lack of
MAC support and care should be taken to identify and mitigate threats MAC support and care should be taken to identify and mitigate threats
from possible tampering outside of these methods. from possible tampering outside of these methods.
An example of this is that a server that modifies READDIR or LOOKUP An example of this is that a server that modifies READDIR or LOOKUP
results based on the client's subject label might want to always results based on the client's subject label might want to always
construct the same subject label for a client which does not present construct the same subject label for a client which does not present
one. This will prevent a non-Labeled NFS client from mixing entries one. This will prevent a non-Labeled NFS client from mixing entries
in the directory cache. in the directory cache.
8. Sharing change attribute implementation details with NFSv4 clients 9. Sharing change attribute implementation details with NFSv4 clients
8.1. Introduction 9.1. Introduction
Although both the NFSv4 [9] and NFSv4.1 protocol [1], define the Although both the NFSv4 [9] and NFSv4.1 protocol [1], define the
change attribute as being mandatory to implement, there is little in change attribute as being mandatory to implement, there is little in
the way of guidance. The only mandated feature is that the value the way of guidance. The only mandated feature is that the value
must change whenever the file data or metadata change. must change whenever the file data or metadata change.
While this allows for a wide range of implementations, it also leaves While this allows for a wide range of implementations, it also leaves
the client with a conundrum: how does it determine which is the most the client with a conundrum: how does it determine which is the most
recent value for the change attribute in a case where several RPC recent value for the change attribute in a case where several RPC
calls have been issued in parallel? In other words if two COMPOUNDs, calls have been issued in parallel? In other words if two COMPOUNDs,
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two change attribute values returned in the replies to the GETATTR two change attribute values returned in the replies to the GETATTR
requests correspond to the most recent state of the file? In some requests correspond to the most recent state of the file? In some
cases, the only recourse may be to send another COMPOUND containing a cases, the only recourse may be to send another COMPOUND containing a
third GETATTR that is fully serialized with the first two. third GETATTR that is fully serialized with the first two.
NFSv4.2 avoids this kind of inefficiency by allowing the server to NFSv4.2 avoids this kind of inefficiency by allowing the server to
share details about how the change attribute is expected to evolve, share details about how the change attribute is expected to evolve,
so that the client may immediately determine which, out of the so that the client may immediately determine which, out of the
several change attribute values returned by the server, is the most several change attribute values returned by the server, is the most
recent. change_attr_type is defined as a new recommended attribute recent. change_attr_type is defined as a new recommended attribute
(see Section 11.2.1), and is per file system. (see Section 12.2.1), and is per file system.
9. Security Considerations 10. Security Considerations
NFSv4.2 has all of the security concerns present in NFSv4.1 (see NFSv4.2 has all of the security concerns present in NFSv4.1 (see
Section 21 of [1]) and those present in the Server-side Copy (see Section 21 of [1]) and those present in the Server-side Copy (see
Section 2.4) and in Labeled NFS (see Section 7.7). Section 3.4) and in Labeled NFS (see Section 8.7).
10. Error Values 11. Error Values
NFS error numbers are assigned to failed operations within a Compound NFS error numbers are assigned to failed operations within a Compound
(COMPOUND or CB_COMPOUND) request. A Compound request contains a (COMPOUND or CB_COMPOUND) request. A Compound request contains a
number of NFS operations that have their results encoded in sequence number of NFS operations that have their results encoded in sequence
in a Compound reply. The results of successful operations will in a Compound reply. The results of successful operations will
consist of an NFS4_OK status followed by the encoded results of the consist of an NFS4_OK status followed by the encoded results of the
operation. If an NFS operation fails, an error status will be operation. If an NFS operation fails, an error status will be
entered in the reply and the Compound request will be terminated. entered in the reply and the Compound request will be terminated.
10.1. Error Definitions 11.1. Error Definitions
Protocol Error Definitions Protocol Error Definitions
+--------------------------+--------+------------------+ +--------------------------+--------+------------------+
| Error | Number | Description | | Error | Number | Description |
+--------------------------+--------+------------------+ +--------------------------+--------+------------------+
| NFS4ERR_BADLABEL | 10093 | Section 10.1.3.1 | | NFS4ERR_BADLABEL | 10093 | Section 11.1.3.1 |
| NFS4ERR_METADATA_NOTSUPP | 10090 | Section 10.1.2.1 | | NFS4ERR_METADATA_NOTSUPP | 10090 | Section 11.1.2.1 |
| NFS4ERR_OFFLOAD_DENIED | 10091 | Section 10.1.2.2 | | NFS4ERR_OFFLOAD_DENIED | 10091 | Section 11.1.2.2 |
| NFS4ERR_PARTNER_NO_AUTH | 10089 | Section 10.1.2.3 | | NFS4ERR_PARTNER_NO_AUTH | 10089 | Section 11.1.2.3 |
| NFS4ERR_PARTNER_NOTSUPP | 10088 | Section 10.1.2.4 | | NFS4ERR_PARTNER_NOTSUPP | 10088 | Section 11.1.2.4 |
| NFS4ERR_UNION_NOTSUPP | 10094 | Section 10.1.1.1 | | NFS4ERR_UNION_NOTSUPP | 10094 | Section 11.1.1.1 |
| NFS4ERR_WRONG_LFS | 10092 | Section 10.1.3.2 | | NFS4ERR_WRONG_LFS | 10092 | Section 11.1.3.2 |
+--------------------------+--------+------------------+ +--------------------------+--------+------------------+
Table 1 Table 1
10.1.1. General Errors 11.1.1. General Errors
This section deals with errors that are applicable to a broad set of This section deals with errors that are applicable to a broad set of
different purposes. different purposes.
10.1.1.1. NFS4ERR_UNION_NOTSUPP (Error Code 10094) 11.1.1.1. NFS4ERR_UNION_NOTSUPP (Error Code 10094)
One of the arguments to the operation is a discriminated union and One of the arguments to the operation is a discriminated union and
while the server supports the given operation, it does not support while the server supports the given operation, it does not support
the selected arm of the discriminated union. For an example, see the selected arm of the discriminated union. For an example, see
READ_PLUS (Section 13.10). READ_PLUS (Section 14.10).
10.1.2. Server to Server Copy Errors 11.1.2. Server to Server Copy Errors
These errors deal with the interaction between server to server These errors deal with the interaction between server to server
copies. copies.
10.1.2.1. NFS4ERR_METADATA_NOTSUPP (Error Code 10090) 11.1.2.1. NFS4ERR_METADATA_NOTSUPP (Error Code 10090)
The destination file cannot support the same metadata as the source The destination file cannot support the same metadata as the source
file. file.
10.1.2.2. NFS4ERR_OFFLOAD_DENIED (Error Code 10091) 11.1.2.2. NFS4ERR_OFFLOAD_DENIED (Error Code 10091)
The copy offload operation is supported by both the source and the The copy offload operation is supported by both the source and the
destination, but the destination is not allowing it for this file. destination, but the destination is not allowing it for this file.
If the client sees this error, it should fall back to the normal copy If the client sees this error, it should fall back to the normal copy
semantics. semantics.
10.1.2.3. NFS4ERR_PARTNER_NO_AUTH (Error Code 10089) 11.1.2.3. NFS4ERR_PARTNER_NO_AUTH (Error Code 10089)
The source server does not authorize a server-to-server copy offload The source server does not authorize a server-to-server copy offload
operation. This may be due to the client's failure to send the operation. This may be due to the client's failure to send the
COPY_NOTIFY operation to the source server, the source server COPY_NOTIFY operation to the source server, the source server
receiving a server-to-server copy offload request after the copy receiving a server-to-server copy offload request after the copy
lease time expired, or for some other permission problem. lease time expired, or for some other permission problem.
10.1.2.4. NFS4ERR_PARTNER_NOTSUPP (Error Code 10088) 11.1.2.4. NFS4ERR_PARTNER_NOTSUPP (Error Code 10088)
The remote server does not support the server-to-server copy offload The remote server does not support the server-to-server copy offload
protocol. protocol.
10.1.3. Labeled NFS Errors 11.1.3. Labeled NFS Errors
These errors are used in Labeled NFS. These errors are used in Labeled NFS.
10.1.3.1. NFS4ERR_BADLABEL (Error Code 10093) 11.1.3.1. NFS4ERR_BADLABEL (Error Code 10093)
The label specified is invalid in some manner. The label specified is invalid in some manner.
10.1.3.2. NFS4ERR_WRONG_LFS (Error Code 10092) 11.1.3.2. NFS4ERR_WRONG_LFS (Error Code 10092)
The LFS specified in the subject label is not compatible with the LFS The LFS specified in the subject label is not compatible with the LFS
in the object label. in the object label.
10.2. New Operations and Their Valid Errors 11.2. New Operations and Their Valid Errors
This section contains a table that gives the valid error returns for This section contains a table that gives the valid error returns for
each new NFSv4.2 protocol operation. The error code NFS4_OK each new NFSv4.2 protocol operation. The error code NFS4_OK
(indicating no error) is not listed but should be understood to be (indicating no error) is not listed but should be understood to be
returnable by all new operations. The error values for all other returnable by all new operations. The error values for all other
operations are defined in Section 15.2 of [1]. operations are defined in Section 15.2 of [1].
Valid Error Returns for Each New Protocol Operation Valid Error Returns for Each New Protocol Operation
+----------------+--------------------------------------------------+ +----------------+--------------------------------------------------+
skipping to change at page 46, line 35 skipping to change at page 50, line 35
| | NFS4ERR_REP_TOO_BIG_TO_CACHE, | | | NFS4ERR_REP_TOO_BIG_TO_CACHE, |
| | NFS4ERR_REQ_TOO_BIG, NFS4ERR_RETRY_UNCACHED_REP, | | | NFS4ERR_REQ_TOO_BIG, NFS4ERR_RETRY_UNCACHED_REP, |
| | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, | | | NFS4ERR_ROFS, NFS4ERR_SERVERFAULT, |
| | NFS4ERR_STALE, NFS4ERR_SYMLINK, | | | NFS4ERR_STALE, NFS4ERR_SYMLINK, |
| | NFS4ERR_TOO_MANY_OPS, NFS4ERR_UNION_NOTSUPP, | | | NFS4ERR_TOO_MANY_OPS, NFS4ERR_UNION_NOTSUPP, |
| | NFS4ERR_WRONG_TYPE | | | NFS4ERR_WRONG_TYPE |
+----------------+--------------------------------------------------+ +----------------+--------------------------------------------------+
Table 2 Table 2
10.3. New Callback Operations and Their Valid Errors 11.3. New Callback Operations and Their Valid Errors
This section contains a table that gives the valid error returns for This section contains a table that gives the valid error returns for
each new NFSv4.2 callback operation. The error code NFS4_OK each new NFSv4.2 callback operation. The error code NFS4_OK
(indicating no error) is not listed but should be understood to be (indicating no error) is not listed but should be understood to be
returnable by all new callback operations. The error values for all returnable by all new callback operations. The error values for all
other callback operations are defined in Section 15.3 of [1]. other callback operations are defined in Section 15.3 of [1].
Valid Error Returns for Each New Protocol Callback Operation Valid Error Returns for Each New Protocol Callback Operation
+------------+------------------------------------------------------+ +------------+------------------------------------------------------+
skipping to change at page 47, line 19 skipping to change at page 51, line 19
| CB_OFFLOAD | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, | | CB_OFFLOAD | NFS4ERR_BADHANDLE, NFS4ERR_BADXDR, |
| | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, | | | NFS4ERR_BAD_STATEID, NFS4ERR_DELAY, |
| | NFS4ERR_OP_NOT_IN_SESSION, NFS4ERR_REP_TOO_BIG, | | | NFS4ERR_OP_NOT_IN_SESSION, NFS4ERR_REP_TOO_BIG, |
| | NFS4ERR_REP_TOO_BIG_TO_CACHE, NFS4ERR_REQ_TOO_BIG, | | | NFS4ERR_REP_TOO_BIG_TO_CACHE, NFS4ERR_REQ_TOO_BIG, |
| | NFS4ERR_RETRY_UNCACHED_REP, NFS4ERR_SERVERFAULT, | | | NFS4ERR_RETRY_UNCACHED_REP, NFS4ERR_SERVERFAULT, |
| | NFS4ERR_TOO_MANY_OPS | | | NFS4ERR_TOO_MANY_OPS |
+------------+------------------------------------------------------+ +------------+------------------------------------------------------+
Table 3 Table 3
11. New File Attributes 12. New File Attributes
11.1. New RECOMMENDED Attributes - List and Definition References 12.1. New RECOMMENDED Attributes - List and Definition References
The list of new RECOMMENDED attributes appears in Table 4. The The list of new RECOMMENDED attributes appears in Table 4. The
meaning of the columns of the table are: meaning of the columns of the table are:
Name: The name of the attribute. Name: The name of the attribute.
Id: The number assigned to the attribute. In the event of conflicts Id: The number assigned to the attribute. In the event of conflicts
between the assigned number and [2], the latter is likely between the assigned number and [2], the latter is likely
authoritative, but should be resolved with Errata to this document authoritative, but should be resolved with Errata to this document
and/or [2]. See [22] for the Errata process. and/or [2]. See [22] for the Errata process.
skipping to change at page 48, line 8 skipping to change at page 52, line 8
W means write-only (SETATTR may set, GETATTR may not retrieve). W means write-only (SETATTR may set, GETATTR may not retrieve).
R W means read/write (GETATTR may retrieve, SETATTR may set). R W means read/write (GETATTR may retrieve, SETATTR may set).
Defined in: The section of this specification that describes the Defined in: The section of this specification that describes the
attribute. attribute.
+------------------+----+-------------------+-----+----------------+ +------------------+----+-------------------+-----+----------------+
| Name | Id | Data Type | Acc | Defined in | | Name | Id | Data Type | Acc | Defined in |
+------------------+----+-------------------+-----+----------------+ +------------------+----+-------------------+-----+----------------+
| change_attr_type | 79 | change_attr_type4 | R | Section 11.2.1 | | change_attr_type | 79 | change_attr_type4 | R | Section 12.2.1 |
| sec_label | 80 | sec_label4 | R W | Section 11.2.2 | | sec_label | 80 | sec_label4 | R W | Section 12.2.2 |
| change_sec_label | 81 | change_sec_label4 | R | Section 11.2.3 | | change_sec_label | 81 | change_sec_label4 | R | Section 12.2.3 |
| space_reserved | 77 | boolean | R W | Section 11.2.4 | | space_reserved | 77 | boolean | R W | Section 12.2.4 |
| space_freed | 78 | length4 | R | Section 11.2.5 | | space_freed | 78 | length4 | R | Section 12.2.5 |
+------------------+----+-------------------+-----+----------------+ +------------------+----+-------------------+-----+----------------+
Table 4 Table 4
11.2. Attribute Definitions 12.2. Attribute Definitions
11.2.1. Attribute 79: change_attr_type 12.2.1. Attribute 79: change_attr_type
enum change_attr_type4 { enum change_attr_type4 {
NFS4_CHANGE_TYPE_IS_MONOTONIC_INCR = 0, NFS4_CHANGE_TYPE_IS_MONOTONIC_INCR = 0,
NFS4_CHANGE_TYPE_IS_VERSION_COUNTER = 1, NFS4_CHANGE_TYPE_IS_VERSION_COUNTER = 1,
NFS4_CHANGE_TYPE_IS_VERSION_COUNTER_NOPNFS = 2, NFS4_CHANGE_TYPE_IS_VERSION_COUNTER_NOPNFS = 2,
NFS4_CHANGE_TYPE_IS_TIME_METADATA = 3, NFS4_CHANGE_TYPE_IS_TIME_METADATA = 3,
NFS4_CHANGE_TYPE_IS_UNDEFINED = 4 NFS4_CHANGE_TYPE_IS_UNDEFINED = 4
}; };
change_attr_type is a per file system attribute which enables the change_attr_type is a per file system attribute which enables the
skipping to change at page 49, line 35 skipping to change at page 53, line 35
be after a COMPOUND containing a SETATTR, WRITE, or CREATE. This be after a COMPOUND containing a SETATTR, WRITE, or CREATE. This
again allows it to detect changes made in parallel by another client. again allows it to detect changes made in parallel by another client.
The value NFS4_CHANGE_TYPE_IS_VERSION_COUNTER_NOPNFS permits the The value NFS4_CHANGE_TYPE_IS_VERSION_COUNTER_NOPNFS permits the
same, but only if the client is not doing pNFS WRITEs. same, but only if the client is not doing pNFS WRITEs.
Finally, if the server does not support change_attr_type or if Finally, if the server does not support change_attr_type or if
NFS4_CHANGE_TYPE_IS_UNDEFINED is set, then the server SHOULD make an NFS4_CHANGE_TYPE_IS_UNDEFINED is set, then the server SHOULD make an
effort to implement the change attribute in terms of the effort to implement the change attribute in terms of the
time_metadata attribute. time_metadata attribute.
11.2.2. Attribute 80: sec_label 12.2.2. Attribute 80: sec_label
typedef uint32_t policy4; typedef uint32_t policy4;
struct labelformat_spec4 { struct labelformat_spec4 {
policy4 lfs_lfs; policy4 lfs_lfs;
policy4 lfs_pi; policy4 lfs_pi;
}; };
struct sec_label4 { struct sec_label4 {
labelformat_spec4 slai_lfs; labelformat_spec4 slai_lfs;
skipping to change at page 50, line 25 skipping to change at page 54, line 25
define a maximum size for the opaque section, slai_data<>. When define a maximum size for the opaque section, slai_data<>. When
creating or modifying a label for an object, the client needs to be creating or modifying a label for an object, the client needs to be
guaranteed that the server will accept a label that is sized guaranteed that the server will accept a label that is sized
correctly. By both client and server being part of a specific MAC correctly. By both client and server being part of a specific MAC
model, the client will be aware of the size. model, the client will be aware of the size.
If a server supports sec_label, then it MUST also support If a server supports sec_label, then it MUST also support
change_sec_label. Any modification to sec_label MUST modify the change_sec_label. Any modification to sec_label MUST modify the
value for change_sec_label. value for change_sec_label.
11.2.3. Attribute 81: change_sec_label 12.2.3. Attribute 81: change_sec_label
struct change_sec_label4 { struct change_sec_label4 {
uint64_t csl_major; uint64_t csl_major;
uint64_t csl_minor; uint64_t csl_minor;
}; };
The change_sec_label attribute is a read-only attribute per file. If The change_sec_label attribute is a read-only attribute per file. If
the value of sec_label for a file is not the same at two disparate the value of sec_label for a file is not the same at two disparate
times then the values of change_sec_label at those times MUST be times then the values of change_sec_label at those times MUST be
different as well. The value of change_sec_label MAY change at other different as well. The value of change_sec_label MAY change at other
times as well, but this should be rare, as that will require the times as well, but this should be rare, as that will require the
client to abort any operation in progress, re-read the label, and client to abort any operation in progress, re-read the label, and
retry the operation. As the sec_label is not bounded by size, this retry the operation. As the sec_label is not bounded by size, this
attribute allows for VERIFY and NVERIFY to quickly determine if the attribute allows for VERIFY and NVERIFY to quickly determine if the
sec_label has been modified. sec_label has been modified.
11.2.4. Attribute 77: space_reserved 12.2.4. Attribute 77: space_reserved
The space_reserve attribute is a read/write attribute of type The space_reserve attribute is a read/write attribute of type
boolean. It is a per file attribute and applies during the lifetime boolean. It is a per file attribute and applies during the lifetime
of the file or until it is turned off. When the space_reserved of the file or until it is turned off. When the space_reserved
attribute is set via SETATTR, the server must ensure that there is attribute is set via SETATTR, the server must ensure that there is
disk space to accommodate every byte in the file before it can return disk space to accommodate every byte in the file before it can return
success. If the server cannot guarantee this, it must return success. If the server cannot guarantee this, it must return
NFS4ERR_NOSPC. NFS4ERR_NOSPC.
If the client tries to grow a file which has the space_reserved If the client tries to grow a file which has the space_reserved
skipping to change at page 51, line 26 skipping to change at page 55, line 26
GETATTR. If the size is retrieved at the same time, the client can GETATTR. If the size is retrieved at the same time, the client can
determine the size of the reservation. determine the size of the reservation.
In order to avoid ambiguity, the space_reserve bit cannot be set In order to avoid ambiguity, the space_reserve bit cannot be set
along with the size bit in SETATTR. Increasing the size of a file along with the size bit in SETATTR. Increasing the size of a file
with space_reserve set will fail if space reservation cannot be with space_reserve set will fail if space reservation cannot be
guaranteed for the new size. If the file size is decreased, space guaranteed for the new size. If the file size is decreased, space
reservation is only guaranteed for the new size. If a hole is reservation is only guaranteed for the new size. If a hole is
punched into the file, then the reservation is not changed. punched into the file, then the reservation is not changed.
11.2.5. Attribute 78: space_freed 12.2.5. Attribute 78: space_freed
space_freed gives the number of bytes freed if the file is deleted. space_freed gives the number of bytes freed if the file is deleted.
This attribute is read only and is of type length4. It is a per file This attribute is read only and is of type length4. It is a per file
attribute. attribute.
12. Operations: REQUIRED, RECOMMENDED, or OPTIONAL 13. Operations: REQUIRED, RECOMMENDED, or OPTIONAL
The following tables summarize the operations of the NFSv4.2 protocol The following tables summarize the operations of the NFSv4.2 protocol
and the corresponding designation of REQUIRED, RECOMMENDED, and and the corresponding designation of REQUIRED, RECOMMENDED, and
OPTIONAL to implement or either OBSOLETE if implemented or MUST NOT OPTIONAL to implement or either END-OF-LIFE or MUST NOT implement.
implement. The designation of OBSOLETE if implemented is reserved The designation of END-OF_LIFE is reserved for those operations which
for those operations which are defined in either NFSv4.0 or NFSV4.1, are defined in either NFSv4.0 or NFSv4.1 and are intended to be
can be implemented in NFSv4.2, and are intended to be MUST NOT be classified as MUST NOT be implemented in NFSv4.3. The designation of
implemented in NFSv4.3. The designation of MUST NOT implement is MUST NOT implement is reserved for those operations that were defined
reserved for those operations that were defined in either NFSv4.0 or in either NFSv4.0 or NFSV4.1 and MUST NOT be implemented in NFSv4.2.
NFSV4.1 and MUST NOT be implemented in NFSv4.2.
For the most part, the REQUIRED, RECOMMENDED, or OPTIONAL designation For the most part, the REQUIRED, RECOMMENDED, or OPTIONAL designation
for operations sent by the client is for the server implementation. for operations sent by the client is for the server implementation.
The client is generally required to implement the operations needed The client is generally required to implement the operations needed
for the operating environment for which it serves. For example, a for the operating environment for which it serves. For example, a
read-only NFSv4.2 client would have no need to implement the WRITE read-only NFSv4.2 client would have no need to implement the WRITE
operation and is not required to do so. operation and is not required to do so.
The REQUIRED or OPTIONAL designation for callback operations sent by The REQUIRED or OPTIONAL designation for callback operations sent by
the server is for both the client and server. Generally, the client the server is for both the client and server. Generally, the client
skipping to change at page 52, line 27 skipping to change at page 56, line 26
The abbreviations used in the second and third columns of the table The abbreviations used in the second and third columns of the table
are defined as follows. are defined as follows.
REQ REQUIRED to implement REQ REQUIRED to implement
REC RECOMMENDED to implement REC RECOMMENDED to implement
OPT OPTIONAL to implement OPT OPTIONAL to implement
OBS OBSOLETE, might be required to implement
MNI MUST NOT implement MNI MUST NOT implement
OBS Also OBSOLESCENT for future versions.
For the NFSv4.2 features that are OPTIONAL, the operations that For the NFSv4.2 features that are OPTIONAL, the operations that
support those features are OPTIONAL, and the server would return support those features are OPTIONAL, and the server would return
NFS4ERR_NOTSUPP in response to the client's use of those operations. NFS4ERR_NOTSUPP in response to the client's use of those operations.
If an OPTIONAL feature is supported, it is possible that a set of If an OPTIONAL feature is supported, it is possible that a set of
operations related to the feature become REQUIRED to implement. The operations related to the feature become REQUIRED to implement. The
third column of the table designates the feature(s) and if the third column of the table designates the feature(s) and if the
operation is REQUIRED or OPTIONAL in the presence of support for the operation is REQUIRED or OPTIONAL in the presence of support for the
feature. feature.
The OPTIONAL features identified and their abbreviations are as The OPTIONAL features identified and their abbreviations are as
follows: follows:
pNFS Parallel NFS pNFS Parallel NFS
FDELG File Delegations FDELG File Delegations
DDELG Directory Delegations DDELG Directory Delegations
COPY Server Side Copy
COPY Server Side Copy
ADH Application Data Holes ADH Application Data Holes
Operations Operations
+----------------------+--------------------+-----------------------+ +----------------------+---------------------+----------------------+
| Operation | REQ, REC, OPT, or | Feature (REQ, REC, or | | Operation | EOL, REQ, REC, OPT, | Feature (REQ, REC, |
| | MNI | OPT) | | | or MNI | or OPT) |
+----------------------+--------------------+-----------------------+ +----------------------+---------------------+----------------------+
| ACCESS | REQ | | | ACCESS | REQ | |
| BACKCHANNEL_CTL | REQ | | | BACKCHANNEL_CTL | REQ | |
| BIND_CONN_TO_SESSION | REQ | | | BIND_CONN_TO_SESSION | REQ | |
| CLOSE | REQ | | | CLOSE | REQ | |
| COMMIT | REQ | | | COMMIT | REQ | |
| COPY | OPT | COPY (REQ) | | COPY | OPT | COPY (REQ) |
| OFFLOAD_ABORT | OPT | COPY (REQ) | | OFFLOAD_ABORT | OPT | COPY (REQ) |
| COPY_NOTIFY | OPT | COPY (REQ) | | COPY_NOTIFY | OPT | COPY (REQ) |
| OFFLOAD_REVOKE | OPT | COPY (REQ) | | OFFLOAD_REVOKE | OPT | COPY (REQ) |
| OFFLOAD_STATUS | OPT | COPY (REQ) | | OFFLOAD_STATUS | OPT | COPY (REQ) |
| CREATE | REQ | | | CREATE | REQ | |
| CREATE_SESSION | REQ | | | CREATE_SESSION | REQ | |
| DELEGPURGE | OPT | FDELG (REQ) | | DELEGPURGE | OPT | FDELG (REQ) |
| DELEGRETURN | OPT | FDELG, DDELG, pNFS | | DELEGRETURN | OPT | FDELG, DDELG, pNFS |
| | | (REQ) | | | | (REQ) |
| DESTROY_CLIENTID | REQ | | | DESTROY_CLIENTID | REQ | |
| DESTROY_SESSION | REQ | | | DESTROY_SESSION | REQ | |
| EXCHANGE_ID | REQ | | | EXCHANGE_ID | REQ | |
| FREE_STATEID | REQ | | | FREE_STATEID | REQ | |
| GETATTR | REQ | | | GETATTR | REQ | |
| GETDEVICEINFO | OPT | pNFS (REQ) | | GETDEVICEINFO | OPT | pNFS (REQ) |
| GETDEVICELIST | OPT | pNFS (OPT) | | GETDEVICELIST | OPT | pNFS (OPT) |
| GETFH | REQ | | | GETFH | REQ | |
| WRITE_PLUS | OPT | ADH (REQ) | | WRITE_PLUS | OPT | ADH (REQ) |
| GET_DIR_DELEGATION | OPT | DDELG (REQ) | | GET_DIR_DELEGATION | OPT | DDELG (REQ) |
| LAYOUTCOMMIT | OPT | pNFS (REQ) | | LAYOUTCOMMIT | OPT | pNFS (REQ) |
| LAYOUTGET | OPT | pNFS (REQ) | | LAYOUTGET | OPT | pNFS (REQ) |
| LAYOUTRETURN | OPT | pNFS (REQ) | | LAYOUTRETURN | OPT | pNFS (REQ) |
| LINK | OPT | | | LINK | OPT | |
| LOCK | REQ | | | LOCK | REQ | |
| LOCKT | REQ | | | LOCKT | REQ | |
| LOCKU | REQ | | | LOCKU | REQ | |
| LOOKUP | REQ | | | LOOKUP | REQ | |
| LOOKUPP | REQ | | | LOOKUPP | REQ | |
| NVERIFY | REQ | | | NVERIFY | REQ | |
| OPEN | REQ | | | OPEN | REQ | |
| OPENATTR | OPT | | | OPENATTR | OPT | |
| OPEN_CONFIRM | MNI | | | OPEN_CONFIRM | MNI | |
| OPEN_DOWNGRADE | REQ | | | OPEN_DOWNGRADE | REQ | |
| PUTFH | REQ | | | PUTFH | REQ | |
| PUTPUBFH | REQ | | | PUTPUBFH | REQ | |
| PUTROOTFH | REQ | | | PUTROOTFH | REQ | |
| READ | OBS | | | READ | REQ (OBS) | |
| READDIR | REQ | | | READDIR | REQ | |
| READLINK | OPT | | | READLINK | OPT | |
| READ_PLUS | OPT | ADH (REQ) | | READ_PLUS | OPT | ADH (REQ) |
| RECLAIM_COMPLETE | REQ | | | RECLAIM_COMPLETE | REQ | |
| RELEASE_LOCKOWNER | MNI | | | RELEASE_LOCKOWNER | MNI | |
| REMOVE | REQ | | | REMOVE | REQ | |
| RENAME | REQ | | | RENAME | REQ | |
| RENEW | MNI | | | RENEW | MNI | |
| RESTOREFH | REQ | | | RESTOREFH | REQ | |
| SAVEFH | REQ | | | SAVEFH | REQ | |
| SECINFO | REQ | | | SECINFO | REQ | |
| SECINFO_NO_NAME | REC | pNFS file layout | | SECINFO_NO_NAME | REC | pNFS file layout |
| | | (REQ) | | | | (REQ) |
| SEQUENCE | REQ | | | SEQUENCE | REQ | |
| SETATTR | REQ | | | SETATTR | REQ | |
| SETCLIENTID | MNI | | | SETCLIENTID | MNI | |
| SETCLIENTID_CONFIRM | MNI | | | SETCLIENTID_CONFIRM | MNI | |
| SET_SSV | REQ | | | SET_SSV | REQ | |
| TEST_STATEID | REQ | | | TEST_STATEID | REQ | |
| VERIFY | REQ | | | VERIFY | REQ | |
| WANT_DELEGATION | OPT | FDELG (OPT) | | WANT_DELEGATION | OPT | FDELG (OPT) |
| WRITE | OBS | | | WRITE | REQ (OBS) | |
+----------------------+--------------------+-----------------------+ +----------------------+---------------------+----------------------+
Callback Operations Callback Operations
+-------------------------+-------------------+---------------------+ +-------------------------+-------------------+---------------------+
| Operation | REQ, REC, OPT, or | Feature (REQ, REC, | | Operation | REQ, REC, OPT, or | Feature (REQ, REC, |
| | MNI | or OPT) | | | MNI | or OPT) |
+-------------------------+-------------------+---------------------+ +-------------------------+-------------------+---------------------+
| CB_OFFLOAD | OPT | COPY (REQ) | | CB_OFFLOAD | OPT | COPY (REQ) |
| CB_GETATTR | OPT | FDELG (REQ) | | CB_GETATTR | OPT | FDELG (REQ) |
| CB_LAYOUTRECALL | OPT | pNFS (REQ) | | CB_LAYOUTRECALL | OPT | pNFS (REQ) |
| CB_NOTIFY | OPT | DDELG (REQ) | | CB_NOTIFY | OPT | DDELG (REQ) |
skipping to change at page 55, line 29 skipping to change at page 59, line 8
| CB_RECALL_ANY | OPT | FDELG, DDELG, pNFS | | CB_RECALL_ANY | OPT | FDELG, DDELG, pNFS |
| | | (REQ) | | | | (REQ) |
| CB_RECALL_SLOT | REQ | | | CB_RECALL_SLOT | REQ | |
| CB_RECALLABLE_OBJ_AVAIL | OPT | DDELG, pNFS (REQ) | | CB_RECALLABLE_OBJ_AVAIL | OPT | DDELG, pNFS (REQ) |
| CB_SEQUENCE | OPT | FDELG, DDELG, pNFS | | CB_SEQUENCE | OPT | FDELG, DDELG, pNFS |
| | | (REQ) | | | | (REQ) |
| CB_WANTS_CANCELLED | OPT | FDELG, DDELG, pNFS | | CB_WANTS_CANCELLED | OPT | FDELG, DDELG, pNFS |
| | | (REQ) | | | | (REQ) |
+-------------------------+-------------------+---------------------+ +-------------------------+-------------------+---------------------+
13. NFSv4.2 Operations 14. NFSv4.2 Operations
13.1. Operation 59: COPY - Initiate a server-side copy 14.1. Operation 59: COPY - Initiate a server-side copy
13.1.1. ARGUMENT 14.1.1. ARGUMENT
const COPY4_GUARDED = 0x00000001; const COPY4_GUARDED = 0x00000001;
const COPY4_METADATA = 0x00000002; const COPY4_METADATA = 0x00000002;
struct COPY4args { struct COPY4args {
/* SAVED_FH: source file */ /* SAVED_FH: source file */
/* CURRENT_FH: destination file or */ /* CURRENT_FH: destination file or */
/* directory */ /* directory */
stateid4 ca_src_stateid; stateid4 ca_src_stateid;
stateid4 ca_dst_stateid; stateid4 ca_dst_stateid;
skipping to change at page 56, line 4 skipping to change at page 59, line 29
/* CURRENT_FH: destination file or */ /* CURRENT_FH: destination file or */
/* directory */ /* directory */
stateid4 ca_src_stateid; stateid4 ca_src_stateid;
stateid4 ca_dst_stateid; stateid4 ca_dst_stateid;
offset4 ca_src_offset; offset4 ca_src_offset;
offset4 ca_dst_offset; offset4 ca_dst_offset;
length4 ca_count; length4 ca_count;
uint32_t ca_flags; uint32_t ca_flags;
component4 ca_destination; component4 ca_destination;
netloc4 ca_source_server<>; netloc4 ca_source_server<>;
}; };
13.1.2. RESULT 14.1.2. RESULT
union COPY4res switch (nfsstat4 cr_status) { union COPY4res switch (nfsstat4 cr_status) {
case NFS4_OK: case NFS4_OK:
write_response4 resok4; write_response4 resok4;
default: default:
length4 cr_bytes_copied; length4 cr_bytes_copied;
}; };
13.1.3. DESCRIPTION 14.1.3. DESCRIPTION
The COPY operation is used for both intra-server and inter-server The COPY operation is used for both intra-server and inter-server
copies. In both cases, the COPY is always sent from the client to copies. In both cases, the COPY is always sent from the client to
the destination server of the file copy. The COPY operation requests the destination server of the file copy. The COPY operation requests
that a file be copied from the location specified by the SAVED_FH that a file be copied from the location specified by the SAVED_FH
value to the location specified by the combination of CURRENT_FH and value to the location specified by the combination of CURRENT_FH and
ca_destination. ca_destination.
The SAVED_FH must be a regular file. If SAVED_FH is not a regular The SAVED_FH must be a regular file. If SAVED_FH is not a regular
file, the operation MUST fail and return NFS4ERR_WRONG_TYPE. file, the operation MUST fail and return NFS4ERR_WRONG_TYPE.
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If the ca_source_server list is specified, then this is an inter- If the ca_source_server list is specified, then this is an inter-
server copy operation and the source file is on a remote server. The server copy operation and the source file is on a remote server. The
client is expected to have previously issued a successful COPY_NOTIFY client is expected to have previously issued a successful COPY_NOTIFY
request to the remote source server. The ca_source_server list MUST request to the remote source server. The ca_source_server list MUST
be the same as the COPY_NOTIFY response's cnr_source_server list. If be the same as the COPY_NOTIFY response's cnr_source_server list. If
the client includes the entries from the COPY_NOTIFY response's the client includes the entries from the COPY_NOTIFY response's
cnr_source_server list in the ca_source_server list, the source cnr_source_server list in the ca_source_server list, the source
server can indicate a specific copy protocol for the destination server can indicate a specific copy protocol for the destination
server to use by returning a URL, which specifies both a protocol server to use by returning a URL, which specifies both a protocol
service and server name. Server-to-server copy protocol service and server name. Server-to-server copy protocol
considerations are described in Section 2.2.5 and Section 2.4.1. considerations are described in Section 3.2.5 and Section 3.4.1.
The ca_flags argument allows the copy operation to be customized in The ca_flags argument allows the copy operation to be customized in
the following ways using the guarded flag (COPY4_GUARDED) and the the following ways using the guarded flag (COPY4_GUARDED) and the
metadata flag (COPY4_METADATA). metadata flag (COPY4_METADATA).
If the guarded flag is set and the destination exists on the server, If the guarded flag is set and the destination exists on the server,
this operation will fail with NFS4ERR_EXIST. this operation will fail with NFS4ERR_EXIST.
If the guarded flag is not set and the destination exists on the If the guarded flag is not set and the destination exists on the
server, the behavior is implementation dependent. server, the behavior is implementation dependent.
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completion status of the operation is indicated by cr_status. completion status of the operation is indicated by cr_status.
If the copy completes successfully, either synchronously or If the copy completes successfully, either synchronously or
asynchronously, the data copied from the source file to the asynchronously, the data copied from the source file to the
destination file MUST appear identical to the NFS client. However, destination file MUST appear identical to the NFS client. However,
the NFS server's on disk representation of the data in the source the NFS server's on disk representation of the data in the source
file and destination file MAY differ. For example, the NFS server file and destination file MAY differ. For example, the NFS server
might encrypt, compress, deduplicate, or otherwise represent the on might encrypt, compress, deduplicate, or otherwise represent the on
disk data in the source and destination file differently. disk data in the source and destination file differently.
13.2. Operation 60: OFFLOAD_ABORT - Cancel a server-side copy 14.2. Operation 60: OFFLOAD_ABORT - Cancel a server-side copy
14.2.1. ARGUMENT
13.2.1. ARGUMENT
struct OFFLOAD_ABORT4args { struct OFFLOAD_ABORT4args {
/* CURRENT_FH: destination file */ /* CURRENT_FH: destination file */
stateid4 oaa_stateid; stateid4 oaa_stateid;
}; };
13.2.2. RESULT 14.2.2. RESULT
struct OFFLOAD_ABORT4res { struct OFFLOAD_ABORT4res {
nfsstat4 oar_status; nfsstat4 oar_status;
}; };
13.2.3. DESCRIPTION 14.2.3. DESCRIPTION
OFFLOAD_ABORT is used for both intra- and inter-server asynchronous OFFLOAD_ABORT is used for both intra- and inter-server asynchronous
copies. The OFFLOAD_ABORT operation allows the client to cancel a copies. The OFFLOAD_ABORT operation allows the client to cancel a
server-side copy operation that it initiated. This operation is sent server-side copy operation that it initiated. This operation is sent
in a COMPOUND request from the client to the destination server. in a COMPOUND request from the client to the destination server.
This operation may be used to cancel a copy when the application that This operation may be used to cancel a copy when the application that
requested the copy exits before the operation is completed or for requested the copy exits before the operation is completed or for
some other reason. some other reason.
The request contains the filehandle and copy stateid cookies that act The request contains the filehandle and copy stateid cookies that act
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The result's oar_status field indicates whether the cancel was The result's oar_status field indicates whether the cancel was
successful or not. A value of NFS4_OK indicates that the copy successful or not. A value of NFS4_OK indicates that the copy
operation was canceled and no callback will be issued by the server. operation was canceled and no callback will be issued by the server.
A copy operation that is successfully canceled may result in none, A copy operation that is successfully canceled may result in none,
some, or all of the data and/or metadata copied. some, or all of the data and/or metadata copied.
If the server supports asynchronous copies, the server is REQUIRED to If the server supports asynchronous copies, the server is REQUIRED to
support the OFFLOAD_ABORT operation. support the OFFLOAD_ABORT operation.
13.3. Operation 61: COPY_NOTIFY - Notify a source server of a future 14.3. Operation 61: COPY_NOTIFY - Notify a source server of a future
copy copy
13.3.1. ARGUMENT 14.3.1. ARGUMENT
struct COPY_NOTIFY4args { struct COPY_NOTIFY4args {
/* CURRENT_FH: source file */ /* CURRENT_FH: source file */
stateid4 cna_src_stateid; stateid4 cna_src_stateid;
netloc4 cna_destination_server; netloc4 cna_destination_server;
}; };
13.3.2. RESULT 14.3.2. RESULT
struct COPY_NOTIFY4resok { struct COPY_NOTIFY4resok {
nfstime4 cnr_lease_time; nfstime4 cnr_lease_time;
netloc4 cnr_source_server<>; netloc4 cnr_source_server<>;
}; };
union COPY_NOTIFY4res switch (nfsstat4 cnr_status) { union COPY_NOTIFY4res switch (nfsstat4 cnr_status) {
case NFS4_OK: case NFS4_OK:
COPY_NOTIFY4resok resok4; COPY_NOTIFY4resok resok4;
default: default:
void; void;
}; };
13.3.3. DESCRIPTION 14.3.3. DESCRIPTION
This operation is used for an inter-server copy. A client sends this This operation is used for an inter-server copy. A client sends this
operation in a COMPOUND request to the source server to authorize a operation in a COMPOUND request to the source server to authorize a
destination server identified by cna_destination_server to read the destination server identified by cna_destination_server to read the
file specified by CURRENT_FH on behalf of the given user. file specified by CURRENT_FH on behalf of the given user.
The cna_src_stateid MUST refer to either open or locking states The cna_src_stateid MUST refer to either open or locking states
provided earlier by the server. If it is invalid, then the operation provided earlier by the server. If it is invalid, then the operation
MUST fail. MUST fail.
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be reachable from the client and might be located on networks to be reachable from the client and might be located on networks to
which the client has no connection. which the client has no connection.
If the client wishes to perform an inter-server copy, the client MUST If the client wishes to perform an inter-server copy, the client MUST
send a COPY_NOTIFY to the source server. Therefore, the source send a COPY_NOTIFY to the source server. Therefore, the source
server MUST support COPY_NOTIFY. server MUST support COPY_NOTIFY.
For a copy only involving one server (the source and destination are For a copy only involving one server (the source and destination are
on the same server), this operation is unnecessary. on the same server), this operation is unnecessary.
13.4. Operation 62: OFFLOAD_REVOKE - Revoke a destination server's copy 14.4. Operation 62: OFFLOAD_REVOKE - Revoke a destination server's copy
privileges privileges
13.4.1. ARGUMENT 14.4.1. ARGUMENT
struct OFFLOAD_REVOKE4args { struct OFFLOAD_REVOKE4args {
/* CURRENT_FH: source file */ /* CURRENT_FH: source file */
netloc4 ora_destination_server; netloc4 ora_destination_server;
}; };
13.4.2. RESULT 14.4.2. RESULT
struct OFFLOAD_REVOKE4res { struct OFFLOAD_REVOKE4res {
nfsstat4 orr_status; nfsstat4 orr_status;
}; };
13.4.3. DESCRIPTION 14.4.3. DESCRIPTION
This operation is used for an inter-server copy. A client sends this This operation is used for an inter-server copy. A client sends this
operation in a COMPOUND request to the source server to revoke the operation in a COMPOUND request to the source server to revoke the
authorization of a destination server identified by authorization of a destination server identified by
ora_destination_server from reading the file specified by CURRENT_FH ora_destination_server from reading the file specified by CURRENT_FH
on behalf of given user. If the ora_destination_server has already on behalf of given user. If the ora_destination_server has already
begun copying the file, a successful return from this operation begun copying the file, a successful return from this operation
indicates that further access will be prevented. indicates that further access will be prevented.
The ora_destination_server MUST be specified using the netloc4 The ora_destination_server MUST be specified using the netloc4
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granted a very long or infinite lease on the destination server's granted a very long or infinite lease on the destination server's
ability to read the source file and all copy operations on the source ability to read the source file and all copy operations on the source
file have been completed. file have been completed.
For a copy only involving one server (the source and destination are For a copy only involving one server (the source and destination are
on the same server), this operation is unnecessary. on the same server), this operation is unnecessary.
If the server supports COPY_NOTIFY, the server is REQUIRED to support If the server supports COPY_NOTIFY, the server is REQUIRED to support
the OFFLOAD_REVOKE operation. the OFFLOAD_REVOKE operation.
13.5. Operation 63: OFFLOAD_STATUS - Poll for status of a server-side 14.5. Operation 63: OFFLOAD_STATUS - Poll for status of a server-side
copy copy
13.5.1. ARGUMENT 14.5.1. ARGUMENT
struct OFFLOAD_STATUS4args { struct OFFLOAD_STATUS4args {
/* CURRENT_FH: destination file */ /* CURRENT_FH: destination file */
stateid4 osa_stateid; stateid4 osa_stateid;
}; };
13.5.2. RESULT 14.5.2. RESULT
struct OFFLOAD_STATUS4resok { struct OFFLOAD_STATUS4resok {
length4 osr_bytes_copied; length4 osr_bytes_copied;
nfsstat4 osr_complete<1>; nfsstat4 osr_complete<1>;
}; };
union OFFLOAD_STATUS4res switch (nfsstat4 osr_status) { union OFFLOAD_STATUS4res switch (nfsstat4 osr_status) {
case NFS4_OK: case NFS4_OK:
OFFLOAD_STATUS4resok osr_resok4; OFFLOAD_STATUS4resok osr_resok4;
default: default:
void; void;
}; };
13.5.3. DESCRIPTION 14.5.3. DESCRIPTION
OFFLOAD_STATUS is used for both intra- and inter-server asynchronous OFFLOAD_STATUS is used for both intra- and inter-server asynchronous
copies. The OFFLOAD_STATUS operation allows the client to poll the copies. The OFFLOAD_STATUS operation allows the client to poll the
destination server to determine the status of an asynchronous copy destination server to determine the status of an asynchronous copy
operation. operation.
If this operation is successful, the number of bytes copied are If this operation is successful, the number of bytes copied are
returned to the client in the osr_bytes_copied field. The returned to the client in the osr_bytes_copied field. The
osr_bytes_copied value indicates the number of bytes copied but not osr_bytes_copied value indicates the number of bytes copied but not
which specific bytes have been copied. which specific bytes have been copied.
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asynchronous copy operation. In all cases, the server will also asynchronous copy operation. In all cases, the server will also
deliver the final results of the asynchronous copy in a CB_OFFLOAD deliver the final results of the asynchronous copy in a CB_OFFLOAD
operation. operation.
The failure of this operation does not indicate the result of the The failure of this operation does not indicate the result of the
asynchronous copy in any way. asynchronous copy in any way.
If the server supports asynchronous copies, the server is REQUIRED to If the server supports asynchronous copies, the server is REQUIRED to
support the OFFLOAD_STATUS operation. support the OFFLOAD_STATUS operation.
13.6. Modification to Operation 42: EXCHANGE_ID - Instantiate Client ID 14.6. Modification to Operation 42: EXCHANGE_ID - Instantiate Client ID
13.6.1. ARGUMENT 14.6.1. ARGUMENT
/* new */ /* new */
const EXCHGID4_FLAG_SUPP_FENCE_OPS = 0x00000004; const EXCHGID4_FLAG_SUPP_FENCE_OPS = 0x00000004;
13.6.2. RESULT 14.6.2. RESULT
Unchanged Unchanged
13.6.3. MOTIVATION 14.6.3. MOTIVATION
Enterprise applications require guarantees that an operation has Enterprise applications require guarantees that an operation has
either aborted or completed. NFSv4.1 provides this guarantee as long either aborted or completed. NFSv4.1 provides this guarantee as long
as the session is alive: simply send a SEQUENCE operation on the same as the session is alive: simply send a SEQUENCE operation on the same
slot with a new sequence number, and the successful return of slot with a new sequence number, and the successful return of
SEQUENCE indicates the previous operation has completed. However, if SEQUENCE indicates the previous operation has completed. However, if
the session is lost, there is no way to know when any in progress the session is lost, there is no way to know when any in progress
operations have aborted or completed. In hindsight, the NFSv4.1 operations have aborted or completed. In hindsight, the NFSv4.1
specification should have mandated that DESTROY_SESSION either abort specification should have mandated that DESTROY_SESSION either abort
or complete all outstanding operations. or complete all outstanding operations.
13.6.4. DESCRIPTION 14.6.4. DESCRIPTION
A client SHOULD request the EXCHGID4_FLAG_SUPP_FENCE_OPS capability A client SHOULD request the EXCHGID4_FLAG_SUPP_FENCE_OPS capability
when it sends an EXCHANGE_ID operation. The server SHOULD set this when it sends an EXCHANGE_ID operation. The server SHOULD set this
capability in the EXCHANGE_ID reply whether the client requests it or capability in the EXCHANGE_ID reply whether the client requests it or
not. It is the server's return that determines whether this not. It is the server's return that determines whether this
capability is in effect. When it is in effect, the following will capability is in effect. When it is in effect, the following will
occur: occur:
o The server will not reply to any DESTROY_SESSION invoked with the o The server will not reply to any DESTROY_SESSION invoked with the
client ID until all operations in progress are completed or client ID until all operations in progress are completed or
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same client owner with a new verifier until all operations in same client owner with a new verifier until all operations in
progress on the client ID's session are completed or aborted. progress on the client ID's session are completed or aborted.
o The NFS server SHOULD support client ID trunking, and if it does o The NFS server SHOULD support client ID trunking, and if it does
and the EXCHGID4_FLAG_SUPP_FENCE_OPS capability is enabled, then a and the EXCHGID4_FLAG_SUPP_FENCE_OPS capability is enabled, then a
session ID created on one node of the storage cluster MUST be session ID created on one node of the storage cluster MUST be
destroyable via DESTROY_SESSION. In addition, DESTROY_CLIENTID destroyable via DESTROY_SESSION. In addition, DESTROY_CLIENTID
and an EXCHANGE_ID with a new verifier affects all sessions and an EXCHANGE_ID with a new verifier affects all sessions
regardless what node the sessions were created on. regardless what node the sessions were created on.
13.7. Operation 64: WRITE_PLUS 14.7. Operation 64: WRITE_PLUS
13.7.1. ARGUMENT
14.7.1. ARGUMENT
struct data_info4 { struct data_info4 {
offset4 di_offset; offset4 di_offset;
length4 di_length; length4 di_length;
bool di_allocated; bool di_allocated;
}; };
struct data4 { struct data4 {
offset4 d_offset; offset4 d_offset;
bool d_allocated; bool d_allocated;
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void; void;
}; };
struct WRITE_PLUS4args { struct WRITE_PLUS4args {
/* CURRENT_FH: file */ /* CURRENT_FH: file */
stateid4 wp_stateid; stateid4 wp_stateid;
stable_how4 wp_stable; stable_how4 wp_stable;
write_plus_arg4 wp_data<>; write_plus_arg4 wp_data<>;
}; };
13.7.2. RESULT 14.7.2. RESULT
struct write_response4 { struct write_response4 {
stateid4 wr_callback_id<1>; stateid4 wr_callback_id<1>;
count4 wr_count; count4 wr_count;
stable_how4 wr_committed; stable_how4 wr_committed;
verifier4 wr_writeverf; verifier4 wr_writeverf;
}; };
union WRITE_PLUS4res switch (nfsstat4 wp_status) { union WRITE_PLUS4res switch (nfsstat4 wp_status) {
case NFS4_OK: case NFS4_OK:
write_response4 wp_resok4; write_response4 wp_resok4;
default: default:
void; void;
}; };
13.7.3. DESCRIPTION 14.7.3. DESCRIPTION
The WRITE_PLUS operation is an extension of the NFSv4.1 WRITE The WRITE_PLUS operation is an extension of the NFSv4.1 WRITE
operation (see Section 18.2 of [1] and writes data to the regular operation (see Section 18.2 of [1] and writes data to the regular
file identified by the current filehandle. The server MAY write file identified by the current filehandle. The server MAY write
fewer bytes than requested by the client. fewer bytes than requested by the client.
The WRITE_PLUS argument is comprised of an array of rpr_contents, The WRITE_PLUS argument is comprised of an array of rpr_contents,
each of which describe a data_content4 type of data (Section 6.1.2). each of which describe a data_content4 type of data (Section 7.1.2).
For NFSv4.2, the allowed values are data, ADH, and hole. The array For NFSv4.2, the allowed values are data, ADH, and hole. The array
contents MUST be contiguous in the file. A successful WRITE_PLUS contents MUST be contiguous in the file. A successful WRITE_PLUS
will construct a reply for wr_count, wr_committed, and wr_writeverf will construct a reply for wr_count, wr_committed, and wr_writeverf
as per the NFSv4.1 WRITE operation results. If wr_callback_id is as per the NFSv4.1 WRITE operation results. If wr_callback_id is
set, it indicates an asynchronous reply (see Section 13.7.3.4). set, it indicates an asynchronous reply (see Section 14.7.3.4).
WRITE_PLUS has to support all of the errors which are returned by WRITE_PLUS has to support all of the errors which are returned by
WRITE plus NFS4ERR_UNION_NOTSUPP. If the client asks for a hole and WRITE plus NFS4ERR_UNION_NOTSUPP. If the client asks for a hole and
the server does not support that arm of the discriminated union, but the server does not support that arm of the discriminated union, but
does support one or more additional arms, it can signal to the client does support one or more additional arms, it can signal to the client
that it supports the operation, but not the arm with that it supports the operation, but not the arm with
NFS4ERR_UNION_NOTSUPP. NFS4ERR_UNION_NOTSUPP.
If the client supports WRITE_PLUS, it MUST support CB_OFFLOAD. If the client supports WRITE_PLUS, it MUST support CB_OFFLOAD.
13.7.3.1. Data 14.7.3.1. Data
The d_offset specifies the offset where the data should be written. The d_offset specifies the offset where the data should be written.
An d_offset of zero specifies that the write should start at the An d_offset of zero specifies that the write should start at the
beginning of the file. The d_count, as encoded as part of the opaque beginning of the file. The d_count, as encoded as part of the opaque
data parameter, represents the number of bytes of data that are to be data parameter, represents the number of bytes of data that are to be
written. If the d_count is zero, the WRITE_PLUS will succeed and written. If the d_count is zero, the WRITE_PLUS will succeed and
return a d_count of zero subject to permissions checking. return a d_count of zero subject to permissions checking.
Note that d_allocated has no meaning for WRITE_PLUS. Note that d_allocated has no meaning for WRITE_PLUS.
13.7.3.2. Hole punching 14.7.3.2. Hole punching
Whenever a client wishes to zero the blocks backing a particular Whenever a client wishes to zero the blocks backing a particular
region in the file, it calls the WRITE_PLUS operation with the region in the file, it calls the WRITE_PLUS operation with the
current filehandle set to the filehandle of the file in question, and current filehandle set to the filehandle of the file in question, and
the equivalent of start offset and length in bytes of the region set the equivalent of start offset and length in bytes of the region set
in wpa_hole.di_offset and wpa_hole.di_length respectively. If the in wpa_hole.di_offset and wpa_hole.di_length respectively. If the
wpa_hole.di_allocated is set to TRUE, then the blocks will be zeroed wpa_hole.di_allocated is set to TRUE, then the blocks will be zeroed
and if it is set to FALSE, then they will be deallocated. All and if it is set to FALSE, then they will be deallocated. All
further reads to this region MUST return zeros until overwritten. further reads to this region MUST return zeros until overwritten.
The filehandle specified must be that of a regular file. The filehandle specified must be that of a regular file.
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deallocations in. For most file systems, this is the block size of deallocations in. For most file systems, this is the block size of
the file system. In such a case, the server can deallocate as many the file system. In such a case, the server can deallocate as many
bytes as it can in the region. The blocks that cannot be deallocated bytes as it can in the region. The blocks that cannot be deallocated
MUST be zeroed. Except for the block deallocation and maximum hole MUST be zeroed. Except for the block deallocation and maximum hole
punching capability, a WRITE_PLUS operation is to be treated similar punching capability, a WRITE_PLUS operation is to be treated similar
to a write of zeroes. to a write of zeroes.
The server is not required to complete deallocating the blocks The server is not required to complete deallocating the blocks
specified in the operation before returning. The server SHOULD specified in the operation before returning. The server SHOULD
return an asynchronous result if it can determine the operation will return an asynchronous result if it can determine the operation will
be long running (see Section 13.7.3.4). be long running (see Section 14.7.3.4).
If used to hole punch, WRITE_PLUS will result in the space_used If used to hole punch, WRITE_PLUS will result in the space_used
attribute being decreased by the number of bytes that were attribute being decreased by the number of bytes that were
deallocated. The space_freed attribute may or may not decrease, deallocated. The space_freed attribute may or may not decrease,
depending on the support and whether the blocks backing the specified depending on the support and whether the blocks backing the specified
range were shared or not. The size attribute will remain unchanged. range were shared or not. The size attribute will remain unchanged.
The WRITE_PLUS operation MUST NOT change the space reservation The WRITE_PLUS operation MUST NOT change the space reservation
guarantee of the file. While the server can deallocate the blocks guarantee of the file. While the server can deallocate the blocks
specified by di_offset and di_length, future writes to this region specified by di_offset and di_length, future writes to this region
MUST NOT fail with NFSERR_NOSPC. MUST NOT fail with NFSERR_NOSPC.
13.7.3.3. ADHs 14.7.3.3. ADHs
If the server supports ADHs, then it MUST support the If the server supports ADHs, then it MUST support the
NFS4_CONTENT_APP_DATA_HOLE arm of the WRITE_PLUS operation. The NFS4_CONTENT_APP_DATA_HOLE arm of the WRITE_PLUS operation. The
server has no concept of the structure imposed by the application. server has no concept of the structure imposed by the application.
It is only when the application writes to a section of the file does It is only when the application writes to a section of the file does
order get imposed. In order to detect corruption even before the order get imposed. In order to detect corruption even before the
application utilizes the file, the application will want to application utilizes the file, the application will want to
initialize a range of ADHs using WRITE_PLUS. initialize a range of ADHs using WRITE_PLUS.
For ADHs, when the client invokes the WRITE_PLUS operation, it has For ADHs, when the client invokes the WRITE_PLUS operation, it has
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1. The structure described by the app_data_block4 be imposed on the 1. The structure described by the app_data_block4 be imposed on the
file. file.
2. The contents described by the app_data_block4 be sparse. 2. The contents described by the app_data_block4 be sparse.
If the server supports the WRITE_PLUS operation, it still might not If the server supports the WRITE_PLUS operation, it still might not
support sparse files. So if it receives the WRITE_PLUS operation, support sparse files. So if it receives the WRITE_PLUS operation,
then it MUST populate the contents of the file with the initialized then it MUST populate the contents of the file with the initialized
ADHs. The server SHOULD return an asynchronous result if it can ADHs. The server SHOULD return an asynchronous result if it can
determine the operation will be long running (see Section 13.7.3.4). determine the operation will be long running (see Section 14.7.3.4).
If the data was already initialized, there are two interesting If the data was already initialized, there are two interesting
scenarios: scenarios:
1. The data blocks are allocated. 1. The data blocks are allocated.
2. Initializing in the middle of an existing ADH. 2. Initializing in the middle of an existing ADH.
If the data blocks were already allocated, then the WRITE_PLUS is a If the data blocks were already allocated, then the WRITE_PLUS is a
hole punch operation. If WRITE_PLUS supports sparse files, then the hole punch operation. If WRITE_PLUS supports sparse files, then the
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This document does not mandate the manner in which the server stores This document does not mandate the manner in which the server stores
ADHs sparsely for a file. However, if an WRITE_PLUS arrives that ADHs sparsely for a file. However, if an WRITE_PLUS arrives that
will force a new ADH to start inside an existing ADH then the server will force a new ADH to start inside an existing ADH then the server
will have three ADHs instead of two. It will have one up to the new will have three ADHs instead of two. It will have one up to the new
one for the WRITE_PLUS, one for the WRITE_PLUS, and one for after the one for the WRITE_PLUS, one for the WRITE_PLUS, and one for after the
WRITE_PLUS. Note that depending on server specific policies for WRITE_PLUS. Note that depending on server specific policies for
block allocation, there may also be some physical blocks allocated to block allocation, there may also be some physical blocks allocated to
align the boundaries. align the boundaries.
13.7.3.4. Asynchronous Transactions 14.7.3.4. Asynchronous Transactions
Both hole punching and ADH initialization may lead to server Both hole punching and ADH initialization may lead to server
determining to service the operation asynchronously. If it decides determining to service the operation asynchronously. If it decides
to do so, it sets the stateid in wr_callback_id to be that of the to do so, it sets the stateid in wr_callback_id to be that of the
wp_stateid. If it does not set the wr_callback_id, then the result wp_stateid. If it does not set the wr_callback_id, then the result
is synchronous. is synchronous.
When the client determines that the reply will be given When the client determines that the reply will be given
asynchronously, it should not assume anything about the contents of asynchronously, it should not assume anything about the contents of
what it wrote until it is informed by the server that the operation what it wrote until it is informed by the server that the operation
is complete. It can use OFFLOAD_STATUS (Section 13.5) to monitor the is complete. It can use OFFLOAD_STATUS (Section 14.5) to monitor the
operation and OFFLOAD_ABORT (Section 13.2) to cancel the operation. operation and OFFLOAD_ABORT (Section 14.2) to cancel the operation.
An example of a asynchronous WRITE_PLUS is shown in Figure 6. An example of a asynchronous WRITE_PLUS is shown in Figure 6.
Client Server Client Server
+ + + +
| | | |
|--- OPEN ---------------------------->| Client opens |--- OPEN ---------------------------->| Client opens
|<------------------------------------/| the file |<------------------------------------/| the file
| | | |
|--- WRITE_PLUS ---------------------->| Client punches |--- WRITE_PLUS ---------------------->| Client punches
|<------------------------------------/| a hole |<------------------------------------/| a hole
skipping to change at page 72, line 38 skipping to change at page 76, line 36
|<------------------------------------/| the file |<------------------------------------/| the file
| | | |
| | | |
Figure 6: An asynchronous WRITE_PLUS. Figure 6: An asynchronous WRITE_PLUS.
When CB_OFFLOAD informs the client of the successful WRITE_PLUS, the When CB_OFFLOAD informs the client of the successful WRITE_PLUS, the
write_response4 embedded in the operation will provide the necessary write_response4 embedded in the operation will provide the necessary
information that a synchronous WRITE_PLUS would have provided. information that a synchronous WRITE_PLUS would have provided.
13.8. Operation 67: IO_ADVISE - Application I/O access pattern hints 14.8. Operation 67: IO_ADVISE - Application I/O access pattern hints
13.8.1. ARGUMENT 14.8.1. ARGUMENT
enum IO_ADVISE_type4 { enum IO_ADVISE_type4 {
IO_ADVISE4_NORMAL = 0, IO_ADVISE4_NORMAL = 0,
IO_ADVISE4_SEQUENTIAL = 1, IO_ADVISE4_SEQUENTIAL = 1,
IO_ADVISE4_SEQUENTIAL_BACKWARDS = 2, IO_ADVISE4_SEQUENTIAL_BACKWARDS = 2,
IO_ADVISE4_RANDOM = 3, IO_ADVISE4_RANDOM = 3,
IO_ADVISE4_WILLNEED = 4, IO_ADVISE4_WILLNEED = 4,
IO_ADVISE4_WILLNEED_OPPORTUNISTIC = 5, IO_ADVISE4_WILLNEED_OPPORTUNISTIC = 5,
IO_ADVISE4_DONTNEED = 6, IO_ADVISE4_DONTNEED = 6,
IO_ADVISE4_NOREUSE = 7, IO_ADVISE4_NOREUSE = 7,
skipping to change at page 73, line 28 skipping to change at page 77, line 28
}; };
struct IO_ADVISE4args { struct IO_ADVISE4args {
/* CURRENT_FH: file */ /* CURRENT_FH: file */
stateid4 iar_stateid; stateid4 iar_stateid;
offset4 iar_offset; offset4 iar_offset;
length4 iar_count; length4 iar_count;
bitmap4 iar_hints; bitmap4 iar_hints;
}; };
13.8.2. RESULT 14.8.2. RESULT
struct IO_ADVISE4resok { struct IO_ADVISE4resok {
bitmap4 ior_hints; bitmap4 ior_hints;
}; };
union IO_ADVISE4res switch (nfsstat4 _status) { union IO_ADVISE4res switch (nfsstat4 _status) {
case NFS4_OK: case NFS4_OK:
IO_ADVISE4resok resok4; IO_ADVISE4resok resok4;
default: default:
void; void;
}; };
13.8.3. DESCRIPTION 14.8.3. DESCRIPTION
The IO_ADVISE operation sends an I/O access pattern hint to the The IO_ADVISE operation sends an I/O access pattern hint to the
server for the owner of the stateid for a given byte range specified server for the owner of the stateid for a given byte range specified
by iar_offset and iar_count. The byte range specified by iar_offset by iar_offset and iar_count. The byte range specified by iar_offset
and iar_count need not currently exist in the file, but the iar_hints and iar_count need not currently exist in the file, but the iar_hints
will apply to the byte range when it does exist. If iar_count is 0, will apply to the byte range when it does exist. If iar_count is 0,
all data following iar_offset is specified. The server MAY ignore all data following iar_offset is specified. The server MAY ignore
the advice. the advice.
The following are the allowed hints for a stateid holder: The following are the allowed hints for a stateid holder:
skipping to change at page 75, line 27 skipping to change at page 79, line 27
perhaps due to a temporary resource limitation. perhaps due to a temporary resource limitation.
Each issuance of the IO_ADVISE operation overrides all previous Each issuance of the IO_ADVISE operation overrides all previous
issuances of IO_ADVISE for a given byte range. This effectively issuances of IO_ADVISE for a given byte range. This effectively
follows a strategy of last hint wins for a given stateid and byte follows a strategy of last hint wins for a given stateid and byte
range. range.
Clients should assume that hints included in an IO_ADVISE operation Clients should assume that hints included in an IO_ADVISE operation
will be forgotten once the file is closed. will be forgotten once the file is closed.
13.8.4. IMPLEMENTATION 14.8.4. IMPLEMENTATION
The NFS client may choose to issue an IO_ADVISE operation to the The NFS client may choose to issue an IO_ADVISE operation to the
server in several different instances. server in several different instances.
The most obvious is in direct response to an application's execution The most obvious is in direct response to an application's execution
of posix_fadvise(). In this case, IO_ADVISE4_WRITE and of posix_fadvise(). In this case, IO_ADVISE4_WRITE and
IO_ADVISE4_READ may be set based upon the type of file access IO_ADVISE4_READ may be set based upon the type of file access
specified when the file was opened. specified when the file was opened.
13.8.5. IO_ADVISE4_INIT_PROXIMITY 14.8.5. IO_ADVISE4_INIT_PROXIMITY
The IO_ADVISE4_INIT_PROXIMITY hint is non-posix in origin and conveys The IO_ADVISE4_INIT_PROXIMITY hint is non-posix in origin and conveys
that the client has recently accessed the byte range in its own that the client has recently accessed the byte range in its own
cache. I.e., it has not accessed it on the server, but it has cache. I.e., it has not accessed it on the server, but it has
locally. When the server reaches resource exhaustion, knowing which locally. When the server reaches resource exhaustion, knowing which
data is more important allows the server to make better choices about data is more important allows the server to make better choices about
which data to, for example purge from a cache, or move to secondary which data to, for example purge from a cache, or move to secondary
storage. It also informs the server which delegations are more storage. It also informs the server which delegations are more
important, since if delegations are working correctly, once delegated important, since if delegations are working correctly, once delegated
to a client and the client has read the content for that byte range, to a client and the client has read the content for that byte range,
a server might never receive another read request for that byte a server might never receive another read request for that byte
range. range.
This hint is also useful in the case of NFS clients which are network This hint is also useful in the case of NFS clients which are network
booting from a server. If the first client to be booted sends this booting from a server. If the first client to be booted sends this
hint, then it keeps the cache warm for the remaining clients. hint, then it keeps the cache warm for the remaining clients.
13.8.6. pNFS File Layout Data Type Considerations 14.8.6. pNFS File Layout Data Type Considerations
The IO_ADVISE considerations for pNFS are very similar to the COMMIT The IO_ADVISE considerations for pNFS are very similar to the COMMIT
considerations for pNFS. That is, as with COMMIT, some NFS server considerations for pNFS. That is, as with COMMIT, some NFS server
implementations prefer IO_ADVISE be done on the DS, and some prefer implementations prefer IO_ADVISE be done on the DS, and some prefer
it be done on the MDS. it be done on the MDS.
So for the file's layout type, it is proposed that NFSv4.2 include an So for the file's layout type, it is proposed that NFSv4.2 include an
additional hint NFL42_CARE_IO_ADVISE_THRU_MDS which is valid only on additional hint NFL42_CARE_IO_ADVISE_THRU_MDS which is valid only on
NFSv4.2 or higher. Any file's layout obtained with NFSv4.1 MUST NOT NFSv4.2 or higher. Any file's layout obtained with NFSv4.1 MUST NOT
have NFL42_UFLG_IO_ADVISE_THRU_MDS set. Any file's layout obtained have NFL42_UFLG_IO_ADVISE_THRU_MDS set. Any file's layout obtained
skipping to change at page 76, line 38 skipping to change at page 80, line 38
send an IO_ADVISE operation to the appropriate DS for the specified send an IO_ADVISE operation to the appropriate DS for the specified
byte range. While the client MAY always send IO_ADVISE to the MDS, byte range. While the client MAY always send IO_ADVISE to the MDS,
if the server has not set NFL42_UFLG_IO_ADVISE_THRU_MDS, the client if the server has not set NFL42_UFLG_IO_ADVISE_THRU_MDS, the client
should expect that such an IO_ADVISE is futile. Note that a client should expect that such an IO_ADVISE is futile. Note that a client
SHOULD use the same set of arguments on each IO_ADVISE sent to a DS SHOULD use the same set of arguments on each IO_ADVISE sent to a DS
for the same open file reference. for the same open file reference.
The server is not required to support different advice for different The server is not required to support different advice for different
DS's with the same open file reference. DS's with the same open file reference.
13.8.6.1. Dense and Sparse Packing Considerations 14.8.6.1. Dense and Sparse Packing Considerations
The IO_ADVISE operation MUST use the iar_offset and byte range as The IO_ADVISE operation MUST use the iar_offset and byte range as
dictated by the presence or absence of NFL4_UFLG_DENSE. dictated by the presence or absence of NFL4_UFLG_DENSE.
E.g., if NFL4_UFLG_DENSE is present, and a READ or WRITE to the DS E.g., if NFL4_UFLG_DENSE is present, and a READ or WRITE to the DS
for iar_offset 0 really means iar_offset 10000 in the logical file, for iar_offset 0 really means iar_offset 10000 in the logical file,
then an IO_ADVISE for iar_offset 0 means iar_offset 10000. then an IO_ADVISE for iar_offset 0 means iar_offset 10000.
E.g., if NFL4_UFLG_DENSE is absent, then a READ or WRITE to the DS E.g., if NFL4_UFLG_DENSE is absent, then a READ or WRITE to the DS
for iar_offset 0 really means iar_offset 0 in the logical file, then for iar_offset 0 really means iar_offset 0 in the logical file, then
skipping to change at page 78, line 9 skipping to change at page 82, line 9
If neither of the flags NFL42_UFLG_IO_ADVISE_THRU_MDS and If neither of the flags NFL42_UFLG_IO_ADVISE_THRU_MDS and
NFL4_UFLG_DENSE are set in the layout, then any IO_ADVISE request NFL4_UFLG_DENSE are set in the layout, then any IO_ADVISE request
sent to the data server with a byte range that overlaps stripe unit sent to the data server with a byte range that overlaps stripe unit
that the data server does not serve MUST NOT result in the status that the data server does not serve MUST NOT result in the status
NFS4ERR_PNFS_IO_HOLE. Instead, the response SHOULD be successful and NFS4ERR_PNFS_IO_HOLE. Instead, the response SHOULD be successful and
if the server applies IO_ADVISE hints on any stripe units that if the server applies IO_ADVISE hints on any stripe units that
overlap with the specified range, those hints SHOULD be indicated in overlap with the specified range, those hints SHOULD be indicated in
the response. the response.
13.9. Changes to Operation 51: LAYOUTRETURN 14.9. Changes to Operation 51: LAYOUTRETURN
13.9.1. Introduction 14.9.1. Introduction
In the pNFS description provided in [1], the client is not capable to In the pNFS description provided in [1], the client is not capable to
relay an error code from the DS to the MDS. In the specification of relay an error code from the DS to the MDS. In the specification of
the Objects-Based Layout protocol [7], use is made of the opaque the Objects-Based Layout protocol [7], use is made of the opaque
lrf_body field of the LAYOUTRETURN argument to do such a relaying of lrf_body field of the LAYOUTRETURN argument to do such a relaying of
error codes. In this section, we define a new data structure to error codes. In this section, we define a new data structure to
enable the passing of error codes back to the MDS and provide some enable the passing of error codes back to the MDS and provide some
guidelines on what both the client and MDS should expect in such guidelines on what both the client and MDS should expect in such
circumstances. circumstances.
skipping to change at page 79, line 5 skipping to change at page 83, line 5
it cannot determine if the client and DS path is working. As with it cannot determine if the client and DS path is working. As with
the case of the DS passing errors to the client, it must be prepared the case of the DS passing errors to the client, it must be prepared
for the MDS to consider such outages as being transitory. for the MDS to consider such outages as being transitory.
The existing LAYOUTRETURN operation is extended by introducing a new The existing LAYOUTRETURN operation is extended by introducing a new
data structure to report errors, layoutreturn_device_error4. Also, data structure to report errors, layoutreturn_device_error4. Also,
layoutreturn_device_error4 is introduced to enable an array of errors layoutreturn_device_error4 is introduced to enable an array of errors
to be reported. to be reported.
13.9.2. ARGUMENT 14.9.2. ARGUMENT
The ARGUMENT specification of the LAYOUTRETURN operation in section The ARGUMENT specification of the LAYOUTRETURN operation in section
18.44.1 of [1] is augmented by the following XDR code [23]: 18.44.1 of [1] is augmented by the following XDR code [23]:
struct layoutreturn_device_error4 { struct layoutreturn_device_error4 {
deviceid4 lrde_deviceid; deviceid4 lrde_deviceid;
nfsstat4 lrde_status; nfsstat4 lrde_status;
nfs_opnum4 lrde_opnum; nfs_opnum4 lrde_opnum;
}; };
struct layoutreturn_error_report4 { struct layoutreturn_error_report4 {
layoutreturn_device_error4 lrer_errors<>; layoutreturn_device_error4 lrer_errors<>;
}; };
13.9.3. RESULT 14.9.3. RESULT
The RESULT of the LAYOUTRETURN operation is unchanged; see section The RESULT of the LAYOUTRETURN operation is unchanged; see section
18.44.2 of [1]. 18.44.2 of [1].
13.9.4. DESCRIPTION 14.9.4. DESCRIPTION
The following text is added to the end of the LAYOUTRETURN operation The following text is added to the end of the LAYOUTRETURN operation
DESCRIPTION in section 18.44.3 of [1]. DESCRIPTION in section 18.44.3 of [1].
When a client uses LAYOUTRETURN with a type of LAYOUTRETURN4_FILE, When a client uses LAYOUTRETURN with a type of LAYOUTRETURN4_FILE,
then if the lrf_body field is NULL, it indicates to the MDS that the then if the lrf_body field is NULL, it indicates to the MDS that the
client experienced no errors. If lrf_body is non-NULL, then the client experienced no errors. If lrf_body is non-NULL, then the
field references error information which is layout type specific. field references error information which is layout type specific.
I.e., the Objects-Based Layout protocol can continue to utilize I.e., the Objects-Based Layout protocol can continue to utilize
lrf_body as specified in [7]. For both Files-Based and Block-Based lrf_body as specified in [7]. For both Files-Based and Block-Based
skipping to change at page 80, line 5 skipping to change at page 84, line 5
Finally the NFS error value (nfsstat4) encountered is provided via Finally the NFS error value (nfsstat4) encountered is provided via
lrde_status and may consist of the following error codes: lrde_status and may consist of the following error codes:
NFS4ERR_NXIO: The client was unable to establish any communication NFS4ERR_NXIO: The client was unable to establish any communication
with the DS. with the DS.
NFS4ERR_*: The client was able to establish communication with the NFS4ERR_*: The client was able to establish communication with the
DS and is returning one of the allowed error codes for the DS and is returning one of the allowed error codes for the
operation denoted by lrde_opnum. operation denoted by lrde_opnum.
13.9.5. IMPLEMENTATION 14.9.5. IMPLEMENTATION
The following text is added to the end of the LAYOUTRETURN operation The following text is added to the end of the LAYOUTRETURN operation
IMPLEMENTATION in section 18.4.4 of [1]. IMPLEMENTATION in section 18.4.4 of [1].
Clients are expected to tolerate transient storage device errors, and Clients are expected to tolerate transient storage device errors, and
hence clients SHOULD NOT use the LAYOUTRETURN error handling for hence clients SHOULD NOT use the LAYOUTRETURN error handling for
device access problems that may be transient. The methods by which a device access problems that may be transient. The methods by which a
client decides whether a device access problem is transient vs. client decides whether a device access problem is transient vs.
persistent are implementation-specific, but may include retrying I/Os persistent are implementation-specific, but may include retrying I/Os
to a data server under appropriate conditions. to a data server under appropriate conditions.
skipping to change at page 80, line 30 skipping to change at page 84, line 30
and SHOULD indicate which storage device or devices was problematic. and SHOULD indicate which storage device or devices was problematic.
The client needs to do this when the DS is being unresponsive in The client needs to do this when the DS is being unresponsive in
order to fence off any failed write attempts, and ensure that they do order to fence off any failed write attempts, and ensure that they do
not end up overwriting any later data being written through the MDS. not end up overwriting any later data being written through the MDS.
If the client does not do this, the MDS MAY issue a layout recall If the client does not do this, the MDS MAY issue a layout recall
callback in order to perform the retried I/O. callback in order to perform the retried I/O.
The client needs to be cognizant that since this error handling is The client needs to be cognizant that since this error handling is
optional in the MDS, the MDS may silently ignore this functionality. optional in the MDS, the MDS may silently ignore this functionality.
Also, as the MDS may consider some issues the client reports to be Also, as the MDS may consider some issues the client reports to be
expected (see Section 13.9.1), the client might find it difficult to expected (see Section 14.9.1), the client might find it difficult to
detect a MDS which has not implemented error handling via detect a MDS which has not implemented error handling via
LAYOUTRETURN. LAYOUTRETURN.
If an MDS is aware that a storage device is proving problematic to a If an MDS is aware that a storage device is proving problematic to a
client, the MDS SHOULD NOT include that storage device in any pNFS client, the MDS SHOULD NOT include that storage device in any pNFS
layouts sent to that client. If the MDS is aware that a storage layouts sent to that client. If the MDS is aware that a storage
device is affecting many clients, then the MDS SHOULD NOT include device is affecting many clients, then the MDS SHOULD NOT include
that storage device in any pNFS layouts sent out. If a client asks that storage device in any pNFS layouts sent out. If a client asks
for a new layout for the file from the MDS, it MUST be prepared for for a new layout for the file from the MDS, it MUST be prepared for
the MDS to return that storage device in the layout. The MDS might the MDS to return that storage device in the layout. The MDS might
not have any choice in using the storage device, i.e., there might not have any choice in using the storage device, i.e., there might
only be one possible layout for the system. Also, in the case of only be one possible layout for the system. Also, in the case of
existing files, the MDS might have no choice in which storage devices existing files, the MDS might have no choice in which storage devices
to hand out to clients. to hand out to clients.
The MDS is not required to indefinitely retain per-client storage The MDS is not required to indefinitely retain per-client storage
device error information. An MDS is also not required to device error information. An MDS is also not required to
automatically reinstate use of a previously problematic storage automatically reinstate use of a previously problematic storage
device; administrative intervention may be required instead. device; administrative intervention may be required instead.
13.10. Operation 65: READ_PLUS 14.10. Operation 65: READ_PLUS
13.10.1. ARGUMENT 14.10.1. ARGUMENT
struct READ_PLUS4args { struct READ_PLUS4args {
/* CURRENT_FH: file */ /* CURRENT_FH: file */
stateid4 rpa_stateid; stateid4 rpa_stateid;
offset4 rpa_offset; offset4 rpa_offset;
count4 rpa_count; count4 rpa_count;
}; };
13.10.2. RESULT 14.10.2. RESULT
struct data_info4 { struct data_info4 {
offset4 di_offset; offset4 di_offset;
length4 di_length; length4 di_length;
bool di_allocated; bool di_allocated;
}; };
struct data4 { struct data4 {
offset4 d_offset; offset4 d_offset;
bool d_allocated; bool d_allocated;
skipping to change at page 82, line 30 skipping to change at page 86, line 30
read_plus_content rpr_contents<>; read_plus_content rpr_contents<>;
}; };
union READ_PLUS4res switch (nfsstat4 rp_status) { union READ_PLUS4res switch (nfsstat4 rp_status) {
case NFS4_OK: case NFS4_OK:
read_plus_res4 rp_resok4; read_plus_res4 rp_resok4;
default: default:
void; void;
}; };
13.10.3. DESCRIPTION 14.10.3. DESCRIPTION
The READ_PLUS operation is based upon the NFSv4.1 READ operation (see The READ_PLUS operation is based upon the NFSv4.1 READ operation (see
Section 18.22 of [1]) and similarly reads data from the regular file Section 18.22 of [1]) and similarly reads data from the regular file
identified by the current filehandle. identified by the current filehandle.
The client provides a rpa_offset of where the READ_PLUS is to start The client provides a rpa_offset of where the READ_PLUS is to start
and a rpa_count of how many bytes are to be read. A rpa_offset of and a rpa_count of how many bytes are to be read. A rpa_offset of
zero means to read data starting at the beginning of the file. If zero means to read data starting at the beginning of the file. If
rpa_offset is greater than or equal to the size of the file, the rpa_offset is greater than or equal to the size of the file, the
status NFS4_OK is returned with di_length (the data length) set to status NFS4_OK is returned with di_length (the data length) set to
zero and eof set to TRUE. zero and eof set to TRUE.
The READ_PLUS result is comprised of an array of rpr_contents, each The READ_PLUS result is comprised of an array of rpr_contents, each
of which describe a data_content4 type of data (Section 6.1.2). For of which describe a data_content4 type of data (Section 7.1.2). For
NFSv4.2, the allowed values are data, ADH, and hole. A server is NFSv4.2, the allowed values are data, ADH, and hole. A server is
required to support the data type, but neither ADH nor hole. Both an required to support the data type, but neither ADH nor hole. Both an
ADH and a hole must be returned in its entirety - clients must be ADH and a hole must be returned in its entirety - clients must be
prepared to get more information than they requested. Both the start prepared to get more information than they requested. Both the start
and the end of the hole may exceed what was requested. The array and the end of the hole may exceed what was requested. The array
contents MUST be contiguous in the file. contents MUST be contiguous in the file.
READ_PLUS has to support all of the errors which are returned by READ READ_PLUS has to support all of the errors which are returned by READ
plus NFS4ERR_UNION_NOTSUPP. If the client asks for a hole and the plus NFS4ERR_UNION_NOTSUPP. If the client asks for a hole and the
server does not support that arm of the discriminated union, but does server does not support that arm of the discriminated union, but does
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For a READ_PLUS with a stateid value of all bits equal to zero, the For a READ_PLUS with a stateid value of all bits equal to zero, the
server MAY allow the READ_PLUS to be serviced subject to mandatory server MAY allow the READ_PLUS to be serviced subject to mandatory
byte-range locks or the current share deny modes for the file. For a byte-range locks or the current share deny modes for the file. For a
READ_PLUS with a stateid value of all bits equal to one, the server READ_PLUS with a stateid value of all bits equal to one, the server
MAY allow READ_PLUS operations to bypass locking checks at the MAY allow READ_PLUS operations to bypass locking checks at the
server. server.
On success, the current filehandle retains its value. On success, the current filehandle retains its value.
13.10.4. IMPLEMENTATION 14.10.4. IMPLEMENTATION
In general, the IMPLEMENTATION notes for READ in Section 18.22.4 of In general, the IMPLEMENTATION notes for READ in Section 18.22.4 of
[1] also apply to READ_PLUS. One delta is that when the owner has a [1] also apply to READ_PLUS. One delta is that when the owner has a
locked byte range, the server MUST return an array of rpr_contents locked byte range, the server MUST return an array of rpr_contents
with values inside that range. with values inside that range.
13.10.4.1. Additional pNFS Implementation Information 14.10.4.1. Additional pNFS Implementation Information
With pNFS, the semantics of using READ_PLUS remains the same. Any With pNFS, the semantics of using READ_PLUS remains the same. Any
data server MAY return a hole or ADH result for a READ_PLUS request data server MAY return a hole or ADH result for a READ_PLUS request
that it receives. When a data server chooses to return such a that it receives. When a data server chooses to return such a
result, it has the option of returning information for the data result, it has the option of returning information for the data
stored on that data server (as defined by the data layout), but it stored on that data server (as defined by the data layout), but it
MUST NOT return results for a byte range that includes data managed MUST NOT return results for a byte range that includes data managed
by another data server. by another data server.
A data server should do its best to return as much information about A data server should do its best to return as much information about
a ADH as is feasible without having to contact the metadata server. a ADH as is feasible without having to contact the metadata server.
If communication with the metadata server is required, then every If communication with the metadata server is required, then every
attempt should be taken to minimize the number of requests. attempt should be taken to minimize the number of requests.
If mandatory locking is enforced, then the data server must also If mandatory locking is enforced, then the data server must also
ensure that to return only information that is within the owner's ensure that to return only information that is within the owner's
locked byte range. locked byte range.
13.10.5. READ_PLUS with Sparse Files Example 14.10.5. READ_PLUS with Sparse Files Example
The following table describes a sparse file. For each byte range, The following table describes a sparse file. For each byte range,
the file contains either non-zero data or a hole. In addition, the the file contains either non-zero data or a hole. In addition, the
server in this example uses a Hole Threshold of 32K. server in this example uses a Hole Threshold of 32K.
+-------------+----------+ +-------------+----------+
| Byte-Range | Contents | | Byte-Range | Contents |
+-------------+----------+ +-------------+----------+
| 0-15999 | Hole | | 0-15999 | Hole |
| 16K-31999 | Non-Zero | | 16K-31999 | Non-Zero |
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the client was requesting. the client was requesting.
3. READ_PLUS(s, 256K, 64K) --> NFS_OK, eof = false, <data[256K, 3. READ_PLUS(s, 256K, 64K) --> NFS_OK, eof = false, <data[256K,
288K], hole[288K, 354K]>. Returns an array of the 32K data and 288K], hole[288K, 354K]>. Returns an array of the 32K data and
the hole which extends to 354K. the hole which extends to 354K.
4. READ_PLUS(s, 354K, 64K) --> NFS_OK, eof = true, <data[354K, 4. READ_PLUS(s, 354K, 64K) --> NFS_OK, eof = true, <data[354K,
418K]>. Returns the final 64K of data and informs the client 418K]>. Returns the final 64K of data and informs the client
there is no more data in the file. there is no more data in the file.
13.11. Operation 66: SEEK 14.11. Operation 66: SEEK
SEEK is an operation that allows a client to determine the location SEEK is an operation that allows a client to determine the location
of the next data_content4 in a file. It allows an implementation of of the next data_content4 in a file. It allows an implementation of
the emerging extension to lseek(2) to allow clients to determine the emerging extension to lseek(2) to allow clients to determine
SEEK_HOLE and SEEK_DATA. SEEK_HOLE and SEEK_DATA.
13.11.1. ARGUMENT 14.11.1. ARGUMENT
struct SEEK4args { struct SEEK4args {
/* CURRENT_FH: file */ /* CURRENT_FH: file */
stateid4 sa_stateid; stateid4 sa_stateid;
offset4 sa_offset; offset4 sa_offset;
data_content4 sa_what; data_content4 sa_what;
}; };
13.11.2. RESULT 14.11.2. RESULT
union seek_content switch (data_content4 content) { union seek_content switch (data_content4 content) {
case NFS4_CONTENT_DATA: case NFS4_CONTENT_DATA:
data_info4 sc_data; data_info4 sc_data;
case NFS4_CONTENT_APP_DATA_HOLE: case NFS4_CONTENT_APP_DATA_HOLE:
app_data_hole4 sc_adh; app_data_hole4 sc_adh;
case NFS4_CONTENT_HOLE: case NFS4_CONTENT_HOLE:
data_info4 sc_hole; data_info4 sc_hole;
default: default:
void; void;
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seek_content sr_contents; seek_content sr_contents;
}; };
union SEEK4res switch (nfsstat4 status) { union SEEK4res switch (nfsstat4 status) {
case NFS4_OK: case NFS4_OK:
seek_res4 resok4; seek_res4 resok4;
default: default:
void; void;
}; };
13.11.3. DESCRIPTION 14.11.3. DESCRIPTION
From the given sa_offset, find the next data_content4 of type sa_what From the given sa_offset, find the next data_content4 of type sa_what
in the file. For either a hole or ADH, this must return the in the file. For either a hole or ADH, this must return the
data_content4 in its entirety. For data, it must not return the data_content4 in its entirety. For data, it must not return the
actual data. actual data.
SEEK must follow the same rules for stateids as READ_PLUS SEEK must follow the same rules for stateids as READ_PLUS
(Section 13.10.3). (Section 14.10.3).
If the server could not find a corresponding sa_what, then the status If the server could not find a corresponding sa_what, then the status
would still be NFS4_OK, but sr_eof would be TRUE. The sr_contents would still be NFS4_OK, but sr_eof would be TRUE. The sr_contents
would contain a zero-ed out content of the appropriate type. would contain a zero-ed out content of the appropriate type.
14. NFSv4.2 Callback Operations 15. NFSv4.2 Callback Operations
14.1. Operation 15: CB_OFFLOAD - Report results of an asynchronous 15.1. Operation 15: CB_OFFLOAD - Report results of an asynchronous
operation operation
14.1.1. ARGUMENT 15.1.1. ARGUMENT
struct write_response4 { struct write_response4 {
stateid4 wr_callback_id<1>; stateid4 wr_callback_id<1>;
count4 wr_count; count4 wr_count;
stable_how4 wr_committed; stable_how4 wr_committed;
verifier4 wr_writeverf; verifier4 wr_writeverf;
}; };
union offload_info4 switch (nfsstat4 coa_status) { union offload_info4 switch (nfsstat4 coa_status) {
case NFS4_OK: case NFS4_OK:
skipping to change at page 88, line 5 skipping to change at page 92, line 5
default: default:
length4 coa_bytes_copied; length4 coa_bytes_copied;
}; };
struct CB_OFFLOAD4args { struct CB_OFFLOAD4args {
nfs_fh4 coa_fh; nfs_fh4 coa_fh;
stateid4 coa_stateid; stateid4 coa_stateid;
offload_info4 coa_offload_info; offload_info4 coa_offload_info;
}; };
14.1.2. RESULT 15.1.2. RESULT
struct CB_OFFLOAD4res { struct CB_OFFLOAD4res {
nfsstat4 cor_status; nfsstat4 cor_status;
}; };
14.1.3. DESCRIPTION 15.1.3. DESCRIPTION
CB_OFFLOAD is used to report to the client the results of an CB_OFFLOAD is used to report to the client the results of an
asynchronous operation, e.g., Server-side Copy or a hole punch. The asynchronous operation, e.g., Server-side Copy or a hole punch. The
coa_fh and coa_stateid identify the transaction and the coa_status coa_fh and coa_stateid identify the transaction and the coa_status
indicates success or failure. The coa_resok4.wr_callback_id MUST NOT indicates success or failure. The coa_resok4.wr_callback_id MUST NOT
be set. If the transaction failed, then the coa_bytes_copied be set. If the transaction failed, then the coa_bytes_copied
contains the number of bytes copied before the failure occurred. The contains the number of bytes copied before the failure occurred. The
coa_bytes_copied value indicates the number of bytes copied but not coa_bytes_copied value indicates the number of bytes copied but not
which specific bytes have been copied. which specific bytes have been copied.
If the client supports either the COPY or WRITE_PLUS operation, the If the client supports either the COPY or WRITE_PLUS operation, the
client is REQUIRED to support the CB_OFFLOAD operation. client is REQUIRED to support the CB_OFFLOAD operation.
There is a potential race between the reply to the original There is a potential race between the reply to the original
transaction on the forechannel and the CB_OFFLOAD callback on the transaction on the forechannel and the CB_OFFLOAD callback on the
backchannel. Sections 2.10.6.3 and 20.9.3 in [1] describes how to backchannel. Sections 2.10.6.3 and 20.9.3 in [1] describes how to
handle this type of issue. handle this type of issue.
14.1.3.1. Server-side Copy 15.1.3.1. Server-side Copy
CB_OFFLOAD is used for both intra- and inter-server asynchronous CB_OFFLOAD is used for both intra- and inter-server asynchronous
copies. This operation is sent by the destination server to the copies. This operation is sent by the destination server to the
client in a CB_COMPOUND request. Upon success, the client in a CB_COMPOUND request. Upon success, the
coa_resok4.wr_count presents the total number of bytes copied. coa_resok4.wr_count presents the total number of bytes copied.
14.1.3.2. WRITE_PLUS 15.1.3.2. WRITE_PLUS
CB_OFFLOAD is used to report the completion of either a hole punch or CB_OFFLOAD is used to report the completion of either a hole punch or
an ADH initialization. Upon success, the coa_resok4 will contain the an ADH initialization. Upon success, the coa_resok4 will contain the
same information that a synchronous WRITE_PLUS would have returned. same information that a synchronous WRITE_PLUS would have returned.
15. IANA Considerations 16. IANA Considerations
This section uses terms that are defined in [24]. This section uses terms that are defined in [24].
16. References 17. References
16.1. Normative References 17.1. Normative References
[1] Shepler, S., Eisler, M., and D. Noveck, "Network File System [1] Shepler, S., Eisler, M., and D. Noveck, "Network File System
(NFS) Version 4 Minor Version 1 Protocol", RFC 5661, (NFS) Version 4 Minor Version 1 Protocol", RFC 5661,
January 2010. January 2010.
[2] Haynes, T., "Network File System (NFS) Version 4 Minor Version [2] Haynes, T., "Network File System (NFS) Version 4 Minor Version
2 External Data Representation Standard (XDR) Description", 2 External Data Representation Standard (XDR) Description",
March 2011. March 2011.
[3] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [3] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
skipping to change at page 89, line 32 skipping to change at page 93, line 32
[5] The Open Group, "Section 'posix_fadvise()' of System Interfaces [5] The Open Group, "Section 'posix_fadvise()' of System Interfaces
of The Open Group Base Specifications Issue 6, IEEE Std 1003.1, of The Open Group Base Specifications Issue 6, IEEE Std 1003.1,
2004 Edition", 2004. 2004 Edition", 2004.
[6] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol [6] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol
Specification", RFC 2203, September 1997. Specification", RFC 2203, September 1997.
[7] Halevy, B., Welch, B., and J. Zelenka, "Object-Based Parallel [7] Halevy, B., Welch, B., and J. Zelenka, "Object-Based Parallel
NFS (pNFS) Operations", RFC 5664, January 2010. NFS (pNFS) Operations", RFC 5664, January 2010.
16.2. Informative References 17.2. Informative References
[8] Bradner, S., "Key words for use in RFCs to Indicate Requirement [8] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", March 1997. Levels", March 1997.
[9] Haynes, T. and D. Noveck, "Network File System (NFS) version 4 [9] Haynes, T. and D. Noveck, "Network File System (NFS) version 4
Protocol", draft-ietf-nfsv4-rfc3530bis-20 (Work In Progress), Protocol", draft-ietf-nfsv4-rfc3530bis-20 (Work In Progress),
October 2012. October 2012.
[10] Lentini, J., Everhart, C., Ellard, D., Tewari, R., and M. Naik, [10] Lentini, J., Everhart, C., Ellard, D., Tewari, R., and M. Naik,
"NSDB Protocol for Federated Filesystems", "NSDB Protocol for Federated Filesystems",
skipping to change at page 92, line 7 skipping to change at page 96, line 7
[RFC Editor: please remove this section prior to publishing this [RFC Editor: please remove this section prior to publishing this
document as an RFC] document as an RFC]
[RFC Editor: prior to publishing this document as an RFC, please [RFC Editor: prior to publishing this document as an RFC, please
replace all occurrences of RFCTBD10 with RFCxxxx where xxxx is the replace all occurrences of RFCTBD10 with RFCxxxx where xxxx is the
RFC number of this document] RFC number of this document]
Author's Address Author's Address
Thomas Haynes Thomas Haynes (editor)
NetApp NetApp
9110 E 66th St 9110 E 66th St
Tulsa, OK 74133 Tulsa, OK 74133
USA USA
Phone: +1 918 307 1415 Phone: +1 918 307 1415
Email: thomas@netapp.com Email: thomas@netapp.com
URI: http://www.tulsalabs.com URI: http://www.tulsalabs.com
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