rfc3010.txt

最新的RFC

Network Working Group                                         S. Shepler
Request for Comments: 3010                                  B. Callaghan
Obsoletes: 1813, 1094                                        D. Robinson
Category: Standards Track                                     R. Thurlow
                                                   Sun Microsystems Inc.
                                                                C. Beame
                                                        Hummingbird Ltd.
                                                               M. Eisler
                                                           Zambeel, Inc.
                                                               D. Noveck
                                                 Network Appliance, Inc.
                                                           December 2000


                         NFS version 4 Protocol

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   NFS (Network File System) version 4 is a distributed file system
   protocol which owes heritage to NFS protocol versions 2 [RFC1094] and
   3 [RFC1813].  Unlike earlier versions, the NFS version 4 protocol
   supports traditional file access while integrating support for file
   locking and the mount protocol.  In addition, support for strong
   security (and its negotiation), compound operations, client caching,
   and internationalization have been added.  Of course, attention has
   been applied to making NFS version 4 operate well in an Internet
   environment.

Key Words

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.






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RFC 3010                 NFS version 4 Protocol            December 2000


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . .   5
   1.1.  Overview of NFS Version 4 Features . . . . . . . . . . . .   6
   1.1.1.  RPC and Security . . . . . . . . . . . . . . . . . . . .   6
   1.1.2.  Procedure and Operation Structure  . . . . . . . . . . .   7
   1.1.3.  File System Model  . . . . . . . . . . . . . . . . . . .   8
   1.1.3.1.  Filehandle Types . . . . . . . . . . . . . . . . . . .   8
   1.1.3.2.  Attribute Types  . . . . . . . . . . . . . . . . . . .   8
   1.1.3.3.  File System Replication and Migration  . . . . . . . .   9
   1.1.4.  OPEN and CLOSE . . . . . . . . . . . . . . . . . . . . .   9
   1.1.5.  File locking . . . . . . . . . . . . . . . . . . . . . .   9
   1.1.6.  Client Caching and Delegation  . . . . . . . . . . . . .  10
   1.2.  General Definitions  . . . . . . . . . . . . . . . . . . .  11
   2.  Protocol Data Types  . . . . . . . . . . . . . . . . . . . .  12
   2.1.  Basic Data Types . . . . . . . . . . . . . . . . . . . . .  12
   2.2.  Structured Data Types  . . . . . . . . . . . . . . . . . .  14
   3.  RPC and Security Flavor  . . . . . . . . . . . . . . . . . .  18
   3.1.  Ports and Transports . . . . . . . . . . . . . . . . . . .  18
   3.2.  Security Flavors . . . . . . . . . . . . . . . . . . . . .  18
   3.2.1.  Security mechanisms for NFS version 4  . . . . . . . . .  19
   3.2.1.1.  Kerberos V5 as security triple . . . . . . . . . . . .  19
   3.2.1.2.  LIPKEY as a security triple  . . . . . . . . . . . . .  19
   3.2.1.3.  SPKM-3 as a security triple  . . . . . . . . . . . . .  20
   3.3.  Security Negotiation . . . . . . . . . . . . . . . . . . .  21
   3.3.1.  Security Error . . . . . . . . . . . . . . . . . . . . .  21
   3.3.2.  SECINFO  . . . . . . . . . . . . . . . . . . . . . . . .  21
   3.4.  Callback RPC Authentication  . . . . . . . . . . . . . . .  22
   4.  Filehandles  . . . . . . . . . . . . . . . . . . . . . . . .  23
   4.1.  Obtaining the First Filehandle . . . . . . . . . . . . . .  24
   4.1.1.  Root Filehandle  . . . . . . . . . . . . . . . . . . . .  24
   4.1.2.  Public Filehandle  . . . . . . . . . . . . . . . . . . .  24
   4.2.  Filehandle Types . . . . . . . . . . . . . . . . . . . . .  25
   4.2.1.  General Properties of a Filehandle . . . . . . . . . . .  25
   4.2.2.  Persistent Filehandle  . . . . . . . . . . . . . . . . .  26
   4.2.3.  Volatile Filehandle  . . . . . . . . . . . . . . . . . .  26
   4.2.4.  One Method of Constructing a Volatile Filehandle . . . .  28
   4.3.  Client Recovery from Filehandle Expiration . . . . . . . .  28
   5.  File Attributes  . . . . . . . . . . . . . . . . . . . . . .  29
   5.1.  Mandatory Attributes . . . . . . . . . . . . . . . . . . .  30
   5.2.  Recommended Attributes . . . . . . . . . . . . . . . . . .  30
   5.3.  Named Attributes . . . . . . . . . . . . . . . . . . . . .  31
   5.4.  Mandatory Attributes - Definitions . . . . . . . . . . . .  31
   5.5.  Recommended Attributes - Definitions . . . . . . . . . . .  33
   5.6.  Interpreting owner and owner_group . . . . . . . . . . . .  38
   5.7.  Character Case Attributes  . . . . . . . . . . . . . . . .  39
   5.8.  Quota Attributes . . . . . . . . . . . . . . . . . . . . .  39
   5.9.  Access Control Lists . . . . . . . . . . . . . . . . . . .  40



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RFC 3010                 NFS version 4 Protocol            December 2000


   5.9.1.  ACE type . . . . . . . . . . . . . . . . . . . . . . . .  41
   5.9.2.  ACE flag . . . . . . . . . . . . . . . . . . . . . . . .  41
   5.9.3.  ACE Access Mask  . . . . . . . . . . . . . . . . . . . .  43
   5.9.4.  ACE who  . . . . . . . . . . . . . . . . . . . . . . . .  44
   6.  File System Migration and Replication  . . . . . . . . . . .  44
   6.1.  Replication  . . . . . . . . . . . . . . . . . . . . . . .  45
   6.2.  Migration  . . . . . . . . . . . . . . . . . . . . . . . .  45
   6.3.  Interpretation of the fs_locations Attribute . . . . . . .  46
   6.4.  Filehandle Recovery for Migration or Replication . . . . .  47
   7.  NFS Server Name Space  . . . . . . . . . . . . . . . . . . .  47
   7.1.  Server Exports . . . . . . . . . . . . . . . . . . . . . .  47
   7.2.  Browsing Exports . . . . . . . . . . . . . . . . . . . . .  48
   7.3.  Server Pseudo File System  . . . . . . . . . . . . . . . .  48
   7.4.  Multiple Roots . . . . . . . . . . . . . . . . . . . . . .  49
   7.5.  Filehandle Volatility  . . . . . . . . . . . . . . . . . .  49
   7.6.  Exported Root  . . . . . . . . . . . . . . . . . . . . . .  49
   7.7.  Mount Point Crossing . . . . . . . . . . . . . . . . . . .  49
   7.8.  Security Policy and Name Space Presentation  . . . . . . .  50
   8.  File Locking and Share Reservations  . . . . . . . . . . . .  50
   8.1.  Locking  . . . . . . . . . . . . . . . . . . . . . . . . .  51
   8.1.1.  Client ID  . . . . . . . . . . . . . . . . . . . . . . .  51
   8.1.2.  Server Release of Clientid . . . . . . . . . . . . . . .  53
   8.1.3.  nfs_lockowner and stateid Definition . . . . . . . . . .  54
   8.1.4.  Use of the stateid . . . . . . . . . . . . . . . . . . .  55
   8.1.5.  Sequencing of Lock Requests  . . . . . . . . . . . . . .  56
   8.1.6.  Recovery from Replayed Requests  . . . . . . . . . . . .  56
   8.1.7.  Releasing nfs_lockowner State  . . . . . . . . . . . . .  57
   8.2.  Lock Ranges  . . . . . . . . . . . . . . . . . . . . . . .  57
   8.3.  Blocking Locks . . . . . . . . . . . . . . . . . . . . . .  58
   8.4.  Lease Renewal  . . . . . . . . . . . . . . . . . . . . . .  58
   8.5.  Crash Recovery . . . . . . . . . . . . . . . . . . . . . .  59
   8.5.1.  Client Failure and Recovery  . . . . . . . . . . . . . .  59
   8.5.2.  Server Failure and Recovery  . . . . . . . . . . . . . .  60
   8.5.3.  Network Partitions and Recovery  . . . . . . . . . . . .  62
   8.6.  Recovery from a Lock Request Timeout or Abort  . . . . . .  63
   8.7.  Server Revocation of Locks . . . . . . . . . . . . . . . .  63
   8.8.  Share Reservations . . . . . . . . . . . . . . . . . . . .  65
   8.9.  OPEN/CLOSE Operations  . . . . . . . . . . . . . . . . . .  65
   8.10.  Open Upgrade and Downgrade  . . . . . . . . . . . . . . .  66
   8.11.  Short and Long Leases . . . . . . . . . . . . . . . . . .  66
   8.12.  Clocks and Calculating Lease Expiration . . . . . . . . .  67
   8.13.  Migration, Replication and State  . . . . . . . . . . . .  67
   8.13.1.  Migration and State . . . . . . . . . . . . . . . . . .  67
   8.13.2.  Replication and State . . . . . . . . . . . . . . . . .  68
   8.13.3.  Notification of Migrated Lease  . . . . . . . . . . . .  69
   9.  Client-Side Caching  . . . . . . . . . . . . . . . . . . . .  69
   9.1.  Performance Challenges for Client-Side Caching . . . . . .  70
   9.2.  Delegation and Callbacks . . . . . . . . . . . . . . . . .  71



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RFC 3010                 NFS version 4 Protocol            December 2000


   9.2.1.  Delegation Recovery  . . . . . . . . . . . . . . . . . .  72
   9.3.  Data Caching . . . . . . . . . . . . . . . . . . . . . . .  74
   9.3.1.  Data Caching and OPENs . . . . . . . . . . . . . . . . .  74
   9.3.2.  Data Caching and File Locking  . . . . . . . . . . . . .  75
   9.3.3.  Data Caching and Mandatory File Locking  . . . . . . . .  77
   9.3.4.  Data Caching and File Identity . . . . . . . . . . . . .  77
   9.4.  Open Delegation  . . . . . . . . . . . . . . . . . . . . .  78
   9.4.1.  Open Delegation and Data Caching . . . . . . . . . . . .  80
   9.4.2.  Open Delegation and File Locks . . . . . . . . . . . . .  82
   9.4.3.  Recall of Open Delegation  . . . . . . . . . . . . . . .  82
   9.4.4.  Delegation Revocation  . . . . . . . . . . . . . . . . .  84
   9.5.  Data Caching and Revocation  . . . . . . . . . . . . . . .  84
   9.5.1.  Revocation Recovery for Write Open Delegation  . . . . .  85
   9.6.  Attribute Caching  . . . . . . . . . . . . . . . . . . . .  85
   9.7.  Name Caching . . . . . . . . . . . . . . . . . . . . . . .  86
   9.8.  Directory Caching  . . . . . . . . . . . . . . . . . . . .  87
   10.  Minor Versioning  . . . . . . . . . . . . . . . . . . . . .  88
   11.  Internationalization  . . . . . . . . . . . . . . . . . . .  91
   11.1.  Universal Versus Local Character Sets . . . . . . . . . .  91
   11.2.  Overview of Universal Character Set Standards . . . . . .  92
   11.3.  Difficulties with UCS-4, UCS-2, Unicode . . . . . . . . .  93
   11.4.  UTF-8 and its solutions . . . . . . . . . . . . . . . . .  94
   11.5.  Normalization . . . . . . . . . . . . . . . . . . . . . .  94
   12.  Error Definitions . . . . . . . . . . . . . . . . . . . . .  95
   13.  NFS Version 4 Requests  . . . . . . . . . . . . . . . . . .  99
   13.1.  Compound Procedure  . . . . . . . . . . . . . . . . . . . 100
   13.2.  Evaluation of a Compound Request  . . . . . . . . . . . . 100
   13.3.  Synchronous Modifying Operations  . . . . . . . . . . . . 101
   13.4.  Operation Values  . . . . . . . . . . . . . . . . . . . . 102
   14.  NFS Version 4 Procedures  . . . . . . . . . . . . . . . . . 102
   14.1.  Procedure 0: NULL - No Operation  . . . . . . . . . . . . 102
   14.2.  Procedure 1: COMPOUND - Compound Operations . . . . . . . 102
   14.2.1.  Operation 3: ACCESS - Check Access Rights . . . . . . . 105
   14.2.2.  Operation 4: CLOSE - Close File . . . . . . . . . . . . 108
   14.2.3.  Operation 5: COMMIT - Commit Cached Data  . . . . . . . 109
   14.2.4.  Operation 6: CREATE - Create a Non-Regular File Object. 112
   14.2.5.  Operation 7: DELEGPURGE - Purge Delegations Awaiting
            Recovery  . . . . . . . . . . . . . . . . . . . . . . . 114
   14.2.6.  Operation 8: DELEGRETURN - Return Delegation  . . . . . 115
   14.2.7.  Operation 9: GETATTR - Get Attributes . . . . . . . . . 115
   14.2.8.  Operation 10: GETFH - Get Current Filehandle  . . . . . 117
   14.2.9.  Operation 11: LINK - Create Link to a File  . . . . . . 118
   14.2.10.  Operation 12: LOCK - Create Lock . . . . . . . . . . . 119
   14.2.11.  Operation 13: LOCKT - Test For Lock  . . . . . . . . . 121
   14.2.12.  Operation 14: LOCKU - Unlock File  . . . . . . . . . . 122
   14.2.13.  Operation 15: LOOKUP - Lookup Filename . . . . . . . . 123
   14.2.14.  Operation 16: LOOKUPP - Lookup Parent Directory  . . . 126




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RFC 3010                 NFS version 4 Protocol            December 2000


   14.2.15.  Operation 17: NVERIFY - Verify Difference in
             Attributes . . . . . . . . . . . . . . . . . . . . . . 127
   14.2.16.  Operation 18: OPEN - Open a Regular File . . . . . . . 128
   14.2.17.  Operation 19: OPENATTR - Open Named Attribute
             Directory  . . . . . . . . . . . . . . . . . . . . . . 137
   14.2.18.  Operation 20: OPEN_CONFIRM - Confirm Open  . . . . . . 138
   14.2.19.  Operation 21: OPEN_DOWNGRADE - Reduce Open File Access 140
   14.2.20.  Operation 22: PUTFH - Set Current Filehandle . . . . . 141
   14.2.21.  Operation 23: PUTPUBFH - Set Public Filehandle . . . . 142
   14.2.22.  Operation 24: PUTROOTFH - Set Root Filehandle  . . . . 143
   14.2.23.  Operation 25: READ - Read from File  . . . . . . . . . 144
   14.2.24.  Operation 26: READDIR - Read Directory . . . . . . . . 146
   14.2.25.  Operation 27: READLINK - Read Symbolic Link  . . . . . 150
   14.2.26.  Operation 28: REMOVE - Remove Filesystem Object  . . . 151
   14.2.27.  Operation 29: RENAME - Rename Directory Entry  . . . . 153
   14.2.28.  Operation 30: RENEW - Renew a Lease  . . . . . . . . . 155
   14.2.29.  Operation 31: RESTOREFH - Restore Saved Filehandle . . 156
   14.2.30.  Operation 32: SAVEFH - Save Current Filehandle . . . . 157
   14.2.31.  Operation 33: SECINFO - Obtain Available Security  . . 158
   14.2.32.  Operation 34: SETATTR - Set Attributes . . . . . . . . 160
   14.2.33.  Operation 35: SETCLIENTID - Negotiate Clientid . . . . 162
   14.2.34.  Operation 36: SETCLIENTID_CONFIRM - Confirm Clientid . 163
   14.2.35.  Operation 37: VERIFY - Verify Same Attributes  . . . . 164
   14.2.36.  Operation 38: WRITE - Write to File  . . . . . . . . . 166
   15.  NFS Version 4 Callback Procedures . . . . . . . . . . . . . 170
   15.1.  Procedure 0: CB_NULL - No Operation . . . . . . . . . . . 170
   15.2.  Procedure 1: CB_COMPOUND - Compound Operations  . . . . . 171
   15.2.1.  Operation 3: CB_GETATTR - Get Attributes  . . . . . . . 172
   15.2.2.  Operation 4: CB_RECALL - Recall an Open Delegation  . . 173
   16.  Security Considerations . . . . . . . . . . . . . . . . . . 174
   17.  IANA Considerations . . . . . . . . . . . . . . . . . . . . 174
   17.1.  Named Attribute Definition  . . . . . . . . . . . . . . . 174
   18.  RPC definition file . . . . . . . . . . . . . . . . . . . . 175
   19.  Bibliography  . . . . . . . . . . . . . . . . . . . . . . . 206
   20.  Authors . . . . . . . . . . . . . . . . . . . . . . . . . . 210
   20.1.  Editor's Address  . . . . . . . . . . . . . . . . . . . . 210
   20.2.  Authors' Addresses  . . . . . . . . . . . . . . . . . . . 210
   20.3.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . 211
   21.  Full Copyright Statement  . . . . . . . . . . . . . . . . . 212

1.  Introduction

   The NFS version 4 protocol is a further revision of the NFS protocol
   defined already by versions 2 [RFC1094] and 3 [RFC1813].  It retains
   the essential characteristics of previous versions: design for easy
   recovery, independent of transport protocols, operating systems and
   filesystems, simplicity, and good performance.  The NFS version 4
   revision has the following goals:



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RFC 3010                 NFS version 4 Protocol            December 2000


   o  Improved access and good performance on the Internet.

      The protocol is designed to transit firewalls easily, perform well