Internet Engineering Task Force (IETF)                    T. Haynes, Ed.
Request for Comments: 7530                                  Primary Data
Obsoletes: 3530                                           D. Noveck, Ed.
Category: Standards Track                                           Dell
ISSN: 2070-1721                                               March 2015

Network File System (NFS) Version 4 Protocol




The Network File System (NFS) version 4 protocol is a distributed file system protocol that builds on the heritage of NFS protocol version 2 (RFC 1094) and version 3 (RFC 1813). Unlike earlier versions, the NFS version 4 protocol supports traditional file access while integrating support for file locking and the MOUNT protocol. In addition, support for strong security (and its negotiation), COMPOUND operations, client caching, and internationalization has been added. Of course, attention has been applied to making NFS version 4 operate well in an Internet environment.

ネットワークファイルシステム(NFS)バージョン4プロトコルは、NFSプロトコルバージョン2(RFC 1094)およびバージョン3(RFC 1813)の遺産を基に構築された分散ファイルシステムプロトコルです。以前のバージョンとは異なり、NFSバージョン4プロトコルは、ファイルロックのサポートとMOUNTプロトコルを統合しながら、従来のファイルアクセスをサポートします。さらに、強力なセキュリティ(およびそのネゴシエーション)、COMPOUND操作、クライアントキャッシング、および国際化のサポートが追加されました。もちろん、NFSバージョン4がインターネット環境で適切に動作するように注意が払われています。

This document, together with the companion External Data Representation (XDR) description document, RFC 7531, obsoletes RFC 3530 as the definition of the NFS version 4 protocol.

このドキュメントは、関連する外部データ表現(XDR)記述ドキュメントであるRFC 7531とともに、NFSバージョン4プロトコルの定義としてRFC 3530を廃止します。

Status of This Memo


This is an Internet Standards Track document.

これはInternet Standards Trackドキュメントです。

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

このドキュメントは、IETF(Internet Engineering Task Force)の製品です。これは、IETFコミュニティのコンセンサスを表しています。公開レビューを受け、インターネットエンジニアリングステアリンググループ(IESG)による公開が承認されました。インターネット標準の詳細については、RFC 5741のセクション2をご覧ください。

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at


Copyright Notice


Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.

Copyright(c)2015 IETF Trustおよびドキュメントの作成者として識別された人物。全著作権所有。

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

この文書は、BCP 78およびこの文書の発行日に有効なIETF文書に関するIETFトラストの法的規定(の対象となります。これらのドキュメントは、このドキュメントに関するあなたの権利と制限を説明しているため、注意深く確認してください。このドキュメントから抽出されたコードコンポーネントには、Trust Legal Provisionsのセクション4.eに記載されているSimplified BSD Licenseのテキストが含まれている必要があり、Simplified BSD Licenseに記載されているように保証なしで提供されます。

This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.

このドキュメントには、2008年11月10日より前に公開または公開されたIETFドキュメントまたはIETFコントリビューションの素材が含まれている場合があります。この素材の一部の著作権を管理する人は、IETFトラストにそのような素材の変更を許可する権利を付与していない可能性がありますIETF標準プロセス外。このような資料の著作権を管理する人から適切なライセンスを取得しない限り、このドキュメントはIETF標準プロセス外で変更できません。また、その派生物は、IETF標準プロセス外で作成できません。 RFCとして、またはそれを英語以外の言語に翻訳するための出版物。

Table of Contents


   1. Introduction ....................................................8
      1.1. Requirements Language ......................................8
      1.2. NFS Version 4 Goals ........................................8
      1.3. Definitions in the Companion Document RFC 7531 Are
           Authoritative ..............................................9
      1.4. Overview of NFSv4 Features .................................9
           1.4.1. RPC and Security ....................................9
           1.4.2. Procedure and Operation Structure ..................10
           1.4.3. File System Model ..................................10
           1.4.4. OPEN and CLOSE .....................................12
           1.4.5. File Locking .......................................12
           1.4.6. Client Caching and Delegation ......................13
      1.5. General Definitions .......................................14
      1.6. Changes since RFC 3530 ....................................16
      1.7. Changes between RFC 3010 and RFC 3530 .....................16
   2. Protocol Data Types ............................................18
      2.1. Basic Data Types ..........................................18
      2.2. Structured Data Types .....................................21
   3. RPC and Security Flavor ........................................25
      3.1. Ports and Transports ......................................25
           3.1.1. Client Retransmission Behavior .....................26
      3.2. Security Flavors ..........................................27
           3.2.1. Security Mechanisms for NFSv4 ......................27
      3.3. Security Negotiation ......................................28
           3.3.1. SECINFO ............................................29
           3.3.2. Security Error .....................................29
           3.3.3. Callback RPC Authentication ........................29
   4. Filehandles ....................................................30
      4.1. Obtaining the First Filehandle ............................30
           4.1.1. Root Filehandle ....................................31
           4.1.2. Public Filehandle ..................................31
      4.2. Filehandle Types ..........................................31
           4.2.1. General Properties of a Filehandle .................32
           4.2.2. Persistent Filehandle ..............................32
           4.2.3. Volatile Filehandle ................................33
           4.2.4. One Method of Constructing a Volatile Filehandle ...34
      4.3. Client Recovery from Filehandle Expiration ................35
   5. Attributes .....................................................35
      5.1. REQUIRED Attributes .......................................37
      5.2. RECOMMENDED Attributes ....................................37
      5.3. Named Attributes ..........................................37
      5.4. Classification of Attributes ..............................39
      5.5. Set-Only and Get-Only Attributes ..........................40
      5.6. REQUIRED Attributes - List and Definition References ......40
      5.7. RECOMMENDED Attributes - List and Definition References ...41
      5.8. Attribute Definitions .....................................42
           5.8.1. Definitions of REQUIRED Attributes .................42
           5.8.2. Definitions of Uncategorized RECOMMENDED
                  Attributes .........................................45
      5.9. Interpreting owner and owner_group ........................51
      5.10. Character Case Attributes ................................53
   6. Access Control Attributes ......................................54
      6.1. Goals .....................................................54
      6.2. File Attributes Discussion ................................55
           6.2.1. Attribute 12: acl ..................................55
           6.2.2. Attribute 33: mode .................................70
      6.3. Common Methods ............................................71
           6.3.1. Interpreting an ACL ................................71
           6.3.2. Computing a mode Attribute from an ACL .............72
      6.4. Requirements ..............................................73
           6.4.1. Setting the mode and/or ACL Attributes .............74
           6.4.2. Retrieving the mode and/or ACL Attributes ..........75
           6.4.3. Creating New Objects ...............................75
   7. NFS Server Namespace ...........................................77
      7.1. Server Exports ............................................77
      7.2. Browsing Exports ..........................................77
      7.3. Server Pseudo-File System .................................78
      7.4. Multiple Roots ............................................79
      7.5. Filehandle Volatility .....................................79
      7.6. Exported Root .............................................79
      7.7. Mount Point Crossing ......................................79
      7.8. Security Policy and Namespace Presentation ................80
   8. Multi-Server Namespace .........................................81
      8.1. Location Attributes .......................................81
      8.2. File System Presence or Absence ...........................81
      8.3. Getting Attributes for an Absent File System ..............83
           8.3.1. GETATTR within an Absent File System ...............83
           8.3.2. READDIR and Absent File Systems ....................84
      8.4. Uses of Location Information ..............................84
           8.4.1. File System Replication ............................85
           8.4.2. File System Migration ..............................86
           8.4.3. Referrals ..........................................86
      8.5. Location Entries and Server Identity ......................87
      8.6. Additional Client-Side Considerations .....................88
      8.7. Effecting File System Referrals ...........................89
           8.7.1. Referral Example (LOOKUP) ..........................89
           8.7.2. Referral Example (READDIR) .........................93
      8.8. The Attribute fs_locations ................................96
   9. File Locking and Share Reservations ............................98
      9.1. Opens and Byte-Range Locks ................................99
           9.1.1. Client ID ..........................................99
           9.1.2. Server Release of Client ID .......................102
           9.1.3. Use of Seqids .....................................103
           9.1.4. Stateid Definition ................................104
           9.1.5. Lock-Owner ........................................110
           9.1.6. Use of the Stateid and Locking ....................110
           9.1.7. Sequencing of Lock Requests .......................113
           9.1.8. Recovery from Replayed Requests ...................114
           9.1.9. Interactions of Multiple Sequence Values ..........114
           9.1.10. Releasing State-Owner State ......................115
           9.1.11. Use of Open Confirmation .........................116
      9.2. Lock Ranges ..............................................117
      9.3. Upgrading and Downgrading Locks ..........................117
      9.4. Blocking Locks ...........................................118
      9.5. Lease Renewal ............................................119
      9.6. Crash Recovery ...........................................120
           9.6.1. Client Failure and Recovery .......................120
           9.6.2. Server Failure and Recovery .......................120
           9.6.3. Network Partitions and Recovery ...................122
      9.7. Recovery from a Lock Request Timeout or Abort ............130
      9.8. Server Revocation of Locks ...............................130
      9.9. Share Reservations .......................................132
      9.10. OPEN/CLOSE Operations ...................................132
           9.10.1. Close and Retention of State Information .........133
      9.11. Open Upgrade and Downgrade ..............................134
      9.12. Short and Long Leases ...................................135
      9.13. Clocks, Propagation Delay, and Calculating Lease
            Expiration ..............................................135
      9.14. Migration, Replication, and State .......................136
           9.14.1. Migration and State ..............................136
           9.14.2. Replication and State ............................137
           9.14.3. Notification of Migrated Lease ...................137
           9.14.4. Migration and the lease_time Attribute ...........138
   10. Client-Side Caching ..........................................139
      10.1. Performance Challenges for Client-Side Caching ..........139
      10.2. Delegation and Callbacks ................................140
           10.2.1. Delegation Recovery ..............................142
      10.3. Data Caching ............................................147
           10.3.1. Data Caching and OPENs ...........................147
           10.3.2. Data Caching and File Locking ....................148
           10.3.3. Data Caching and Mandatory File Locking ..........150
           10.3.4. Data Caching and File Identity ...................150
      10.4. Open Delegation .........................................151
           10.4.1. Open Delegation and Data Caching .................154
           10.4.2. Open Delegation and File Locks ...................155
           10.4.3. Handling of CB_GETATTR ...........................155
           10.4.4. Recall of Open Delegation ........................158
           10.4.5. OPEN Delegation Race with CB_RECALL ..............160
           10.4.6. Clients That Fail to Honor Delegation Recalls ....161
           10.4.7. Delegation Revocation ............................162
      10.5. Data Caching and Revocation .............................162
           10.5.1. Revocation Recovery for Write Open Delegation ....163
      10.6. Attribute Caching .......................................164
      10.7. Data and Metadata Caching and Memory-Mapped Files .......166
      10.8. Name Caching ............................................168
      10.9. Directory Caching .......................................169
   11. Minor Versioning .............................................170
   12. Internationalization .........................................170
      12.1. Introduction ............................................170
      12.2. Limitations on Internationalization-Related
            Processing in the NFSv4 Context .........................172
      12.3. Summary of Server Behavior Types ........................173
      12.4. String Encoding .........................................173
      12.5. Normalization ...........................................174
      12.6. Types with Processing Defined by Other Internet Areas ...175
      12.7. Errors Related to UTF-8 .................................177
      12.8. Servers That Accept File Component Names That
            Are Not Valid UTF-8 Strings .............................177
   13. Error Values .................................................178
      13.1. Error Definitions .......................................179
           13.1.1. General Errors ...................................180
           13.1.2. Filehandle Errors ................................181
           13.1.3. Compound Structure Errors ........................183
           13.1.4. File System Errors ...............................184
           13.1.5. State Management Errors ..........................186
           13.1.6. Security Errors ..................................187
           13.1.7. Name Errors ......................................187
           13.1.8. Locking Errors ...................................188
           13.1.9. Reclaim Errors ...................................190
           13.1.10. Client Management Errors ........................191
           13.1.11. Attribute Handling Errors .......................191
           13.1.12. Miscellaneous Errors ............................191
      13.2. Operations and Their Valid Errors .......................192
      13.3. Callback Operations and Their Valid Errors ..............200
      13.4. Errors and the Operations That Use Them .................201
   14. NFSv4 Requests ...............................................206
      14.1. COMPOUND Procedure ......................................207
      14.2. Evaluation of a COMPOUND Request ........................207
      14.3. Synchronous Modifying Operations ........................208
      14.4. Operation Values ........................................208
   15. NFSv4 Procedures .............................................209
      15.1. Procedure 0: NULL - No Operation ........................209
      15.2. Procedure 1: COMPOUND - COMPOUND Operations .............210
   16. NFSv4 Operations .............................................214
      16.1. Operation 3: ACCESS - Check Access Rights ...............214
      16.2. Operation 4: CLOSE - Close File .........................217
      16.3. Operation 5: COMMIT - Commit Cached Data ................218
      16.4. Operation 6: CREATE - Create a Non-regular File Object ..221
      16.5. Operation 7: DELEGPURGE - Purge Delegations
            Awaiting Recovery .......................................224
      16.6. Operation 8: DELEGRETURN - Return Delegation ............226
      16.7. Operation 9: GETATTR - Get Attributes ...................227
      16.8. Operation 10: GETFH - Get Current Filehandle ............229
      16.9. Operation 11: LINK - Create Link to a File ..............230
      16.10. Operation 12: LOCK - Create Lock .......................232
      16.11. Operation 13: LOCKT - Test for Lock ....................236
      16.12. Operation 14: LOCKU - Unlock File ......................238
      16.13. Operation 15: LOOKUP - Look Up Filename ................240
      16.14. Operation 16: LOOKUPP - Look Up Parent Directory .......242
      16.15. Operation 17: NVERIFY - Verify Difference in
             Attributes .............................................243
      16.16. Operation 18: OPEN - Open a Regular File ...............245
      16.17. Operation 19: OPENATTR - Open Named Attribute
             Directory ..............................................256
      16.18. Operation 20: OPEN_CONFIRM - Confirm Open ..............257
      16.19. Operation 21: OPEN_DOWNGRADE - Reduce Open File
             Access .................................................260
      16.20. Operation 22: PUTFH - Set Current Filehandle ...........262
      16.21. Operation 23: PUTPUBFH - Set Public Filehandle .........263
      16.22. Operation 24: PUTROOTFH - Set Root Filehandle ..........265
      16.23. Operation 25: READ - Read from File ....................266
      16.24. Operation 26: READDIR - Read Directory .................269
      16.25. Operation 27: READLINK - Read Symbolic Link ............273
      16.26. Operation 28: REMOVE - Remove File System Object .......274
      16.27. Operation 29: RENAME - Rename Directory Entry ..........276
      16.28. Operation 30: RENEW - Renew a Lease ....................278
      16.29. Operation 31: RESTOREFH - Restore Saved Filehandle .....280
      16.30. Operation 32: SAVEFH - Save Current Filehandle .........281
      16.31. Operation 33: SECINFO - Obtain Available Security ......282
      16.32. Operation 34: SETATTR - Set Attributes .................286
      16.33. Operation 35: SETCLIENTID - Negotiate Client ID ........289
      16.34. Operation 36: SETCLIENTID_CONFIRM - Confirm Client ID ..293
      16.35. Operation 37: VERIFY - Verify Same Attributes ..........297
      16.36. Operation 38: WRITE - Write to File ....................299
      16.37. Operation 39: RELEASE_LOCKOWNER - Release
             Lock-Owner State .......................................304
      16.38. Operation 10044: ILLEGAL - Illegal Operation ...........305
   17. NFSv4 Callback Procedures ....................................306
      17.1. Procedure 0: CB_NULL - No Operation .....................306
      17.2. Procedure 1: CB_COMPOUND - COMPOUND Operations ..........307
   18. NFSv4 Callback Operations ....................................309
      18.1. Operation 3: CB_GETATTR - Get Attributes ................309
      18.2. Operation 4: CB_RECALL - Recall an Open Delegation ......310
      18.3. Operation 10044: CB_ILLEGAL - Illegal Callback
            Operation ...............................................311
   19. Security Considerations ......................................312
   20. IANA Considerations ..........................................314
      20.1. Named Attribute Definitions .............................314
           20.1.1. Initial Registry .................................315
           20.1.2. Updating Registrations ...........................315
      20.2. Updates to Existing IANA Registries .....................315
   21. References ...................................................316
      21.1. Normative References ....................................316
      21.2. Informative References ..................................318
   Acknowledgments ..................................................322
   Authors' Addresses ...............................................323
1. Introduction
1. はじめに
1.1. Requirements Language
1.1. 要件言語

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 [RFC2119], except where "REQUIRED" and "RECOMMENDED" are used as qualifiers to distinguish classes of attributes as described in Sections and 5 of this document.

このドキュメントのキーワード「MUST」、「MUST NOT」、「REQUIRED」、「SHALL」、「SHALL NOT」、「SHOULD」、「SHOULD NOT」、「RECOMMENDED」、「MAY」、および「OPTIONAL」は、このドキュメントのセクション1.4.3.2および5で説明されているように、属性のクラスを区別するための修飾子として「必須」および「推奨」が使用されている場合を除き、RFC 2119 [RFC2119]で説明されているように解釈されます。

1.2. NFS Version 4 Goals
1.2. NFSバージョン4の目標

The Network File System version 4 (NFSv4) 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 file systems; simplicity; and good performance. The NFSv4 revision has the following goals:

Network File Systemバージョン4(NFSv4)プロトコルは、バージョン2 [RFC1094]および3 [RFC1813]ですでに定義されているNFSプロトコルのさらなる改訂版です。以前のバージョンの本質的な特徴を保持しています。トランスポートプロトコル、オペレーティングシステム、ファイルシステムに依存しない。シンプルさ。そして良いパフォーマンス。 NFSv4リビジョンには次の目標があります。

o Improved access and good performance on the Internet.

o インターネット上でのアクセスとパフォーマンスの向上。

The protocol is designed to transit firewalls easily, perform well where latency is high and bandwidth is low, and scale to very large numbers of clients per server.


o Strong security with negotiation built into the protocol.

o プロトコルにネゴシエーションが組み込まれた強力なセキュリティ。

The protocol builds on the work of the Open Network Computing (ONC) Remote Procedure Call (RPC) working group in supporting the RPCSEC_GSS protocol (see both [RFC2203] and [RFC5403]). Additionally, the NFSv4 protocol provides a mechanism to allow clients and servers the ability to negotiate security and require clients and servers to support a minimal set of security schemes.

このプロトコルは、RPCSEC_GSSプロトコル([RFC2203]と[RFC5403]の両方を参照)をサポートするOpen Network Computing(ONC)リモートプロシージャコール(RPC)ワーキンググループの作業に基づいています。さらに、NFSv4プロトコルは、クライアントとサーバーがセキュリティをネゴシエートできるようにするメカニズムを提供し、クライアントとサーバーが最小限のセキュリティスキームのセットをサポートすることを要求します。

o Good cross-platform interoperability.

o 優れたクロスプラットフォームの相互運用性。

The protocol features a file system model that provides a useful, common set of features that does not unduly favor one file system or operating system over another.


o Designed for protocol extensions.

o プロトコル拡張用に設計されています。

The protocol is designed to accept standard extensions that do not compromise backward compatibility.


This document, together with the companion External Data Representation (XDR) description document [RFC7531], obsoletes [RFC3530] as the authoritative document describing NFSv4. It does not introduce any over-the-wire protocol changes, in the sense that previously valid requests remain valid.


1.3. Definitions in the Companion Document RFC 7531 Are Authoritative
1.3. コンパニオンドキュメントRFC 7531の定義は信頼できる

The "Network File System (NFS) Version 4 External Data Representation Standard (XDR) Description" [RFC7531] contains the definitions in XDR description language of the constructs used by the protocol. Inside this document, several of the constructs are reproduced for purposes of explanation. The reader is warned of the possibility of errors in the reproduced constructs outside of [RFC7531]. For any part of the document that is inconsistent with [RFC7531], [RFC7531] is to be considered authoritative.

「ネットワークファイルシステム(NFS)バージョン4外部データ表現標準(XDR)記述」[RFC7531]には、プロトコルで使用される構成のXDR記述言語での定義が含まれています。このドキュメントでは、説明のためにいくつかの構成要素が複製されています。読者は、[RFC7531]の外で複製された構成にエラーの可能性があることを警告されます。 [RFC7531]と矛盾するドキュメントの部分については、[RFC7531]は信頼できると見なされます。

1.4. Overview of NFSv4 Features
1.4. NFSv4機能の概要

To provide a reasonable context for the reader, the major features of the NFSv4 protocol will be reviewed in brief. This is done to provide an appropriate context for both the reader who is familiar with the previous versions of the NFS protocol and the reader who is new to the NFS protocols. For the reader new to the NFS protocols, some fundamental knowledge is still expected. The reader should be familiar with the XDR and RPC protocols as described in [RFC4506] and [RFC5531]. A basic knowledge of file systems and distributed file systems is expected as well.

読者に妥当なコンテキストを提供するために、NFSv4プロトコルの主要な機能を簡単に復習します。これは、NFSプロトコルの以前のバージョンに精通している読者と、NFSプロトコルに不慣れな読者の両方に適切なコンテキストを提供するために行われます。 NFSプロトコルに不慣れな読者のために、いくつかの基本的な知識がまだ期待されています。 [RFC4506]および[RFC5531]で説明されているように、読者はXDRおよびRPCプロトコルに精通している必要があります。ファイルシステムと分散ファイルシステムの基本的な知識も必要です。

1.4.1. RPC and Security
1.4.1. RPCとセキュリティ

As with previous versions of NFS, the XDR and RPC mechanisms used for the NFSv4 protocol are those defined in [RFC4506] and [RFC5531]. To meet end-to-end security requirements, the RPCSEC_GSS framework (both version 1 in [RFC2203] and version 2 in [RFC5403]) will be used to extend the basic RPC security. With the use of RPCSEC_GSS, various mechanisms can be provided to offer authentication, integrity, and privacy to the NFSv4 protocol. Kerberos V5 will be used as described in [RFC4121] to provide one security framework. With the use of RPCSEC_GSS, other mechanisms may also be specified and used for NFSv4 security.

以前のバージョンのNFSと同様に、NFSv4プロトコルに使用されるXDRおよびRPCメカニズムは、[RFC4506]および[RFC5531]で定義されたものです。エンドツーエンドのセキュリティ要件を満たすために、RPCSEC_GSSフレームワーク([RFC2203]のバージョン1と[RFC5403]のバージョン2の両方)を使用して、基本的なRPCセキュリティを拡張します。 RPCSEC_GSSを使用すると、NFSv4プロトコルに認証、整合性、およびプライバシーを提供するさまざまなメカニズムを提供できます。 [RFC4121]で説明されているようにKerberos V5を使用して、1つのセキュリティフレームワークを提供します。 RPCSEC_GSSを使用すると、NFSv4セキュリティーに他のメカニズムを指定して使用することもできます。

To enable in-band security negotiation, the NFSv4 protocol has added a new operation that provides the client with a method of querying the server about its policies regarding which security mechanisms must be used for access to the server's file system resources. With this, the client can securely match the security mechanism that meets the policies specified at both the client and server.


1.4.2. Procedure and Operation Structure
1.4.2. 手順と操作構造

A significant departure from the previous versions of the NFS protocol is the introduction of the COMPOUND procedure. For the NFSv4 protocol, there are two RPC procedures: NULL and COMPOUND. The COMPOUND procedure is defined in terms of operations, and these operations correspond more closely to the traditional NFS procedures.

NFSプロトコルの以前のバージョンからの大きな違いは、COMPOUNDプロシージャの導入です。 NFSv4プロトコルの場合、NULLとCOMPOUNDの2つのRPCプロシージャがあります。 COMPOUNDプロシージャは操作に関して定義されており、これらの操作は従来のNFSプロシージャにより密接に対応しています。

With the use of the COMPOUND procedure, the client is able to build simple or complex requests. These COMPOUND requests allow for a reduction in the number of RPCs needed for logical file system operations. For example, without previous contact with a server a client will be able to read data from a file in one request by combining LOOKUP, OPEN, and READ operations in a single COMPOUND RPC. With previous versions of the NFS protocol, this type of single request was not possible.

COMPOUNDプロシージャを使用すると、クライアントは単純または複雑な要求を作成できます。これらのCOMPOUND要求により、論理ファイルシステム操作に必要なRPCの数を減らすことができます。たとえば、サーバーとの以前の接続がなければ、クライアントは、LOOKUP、OPEN、およびREAD操作を1つのCOMPOUND RPCで組み合わせることにより、1つの要求でファイルからデータを読み取ることができます。以前のバージョンのNFSプロトコルでは、このタイプの単一要求は不可能でした。

The model used for COMPOUND is very simple. There is no logical OR or ANDing of operations. The operations combined within a COMPOUND request are evaluated in order by the server. Once an operation returns a failing result, the evaluation ends and the results of all evaluated operations are returned to the client.

COMPOUNDに使用されるモデルは非常に単純です。操作の論理ORまたはAND演算はありません。 COMPOUNDリクエスト内で結合された操作は、サーバーによって順番に評価されます。操作が失敗した結果を返すと、評価は終了し、評価されたすべての操作の結果がクライアントに返されます。

The NFSv4 protocol continues to have the client refer to a file or directory at the server by a "filehandle". The COMPOUND procedure has a method of passing a filehandle from one operation to another within the sequence of operations. There is a concept of a current filehandle and a saved filehandle. Most operations use the current filehandle as the file system object to operate upon. The saved filehandle is used as temporary filehandle storage within a COMPOUND procedure as well as an additional operand for certain operations.

NFSv4プロトコルは、クライアントに「ファイルハンドル」によってサーバーのファイルまたはディレクトリを参照させ続けます。 COMPOUNDプロシージャには、一連の操作内である操作から別の操作にファイルハンドルを渡す方法があります。現在のファイルハンドルと保存されたファイルハンドルの概念があります。ほとんどの操作は、操作対象のファイルシステムオブジェクトとして現在のファイルハンドルを使用します。保存されたファイルハンドルは、COMPOUNDプロシージャ内の一時ファイルハンドルストレージとして使用され、特定の操作の追加のオペランドとしても使用されます。

1.4.3. File System Model
1.4.3. ファイルシステムモデル

The general file system model used for the NFSv4 protocol is the same as previous versions. The server file system is hierarchical, with the regular files contained within being treated as opaque byte streams. In a slight departure, file and directory names are encoded with UTF-8 to deal with the basics of internationalization.


The NFSv4 protocol does not require a separate protocol to provide for the initial mapping between pathname and filehandle. Instead of using the older MOUNT protocol for this mapping, the server provides a root filehandle that represents the logical root or top of the file system tree provided by the server. The server provides multiple file systems by gluing them together with pseudo-file systems. These pseudo-file systems provide for potential gaps in the pathnames between real file systems.

NFSv4プロトコルは、パス名とファイルハンドル間の初期マッピングを提供するために、別個のプロトコルを必要としません。このマッピングに古いMOUNTプロトコルを使用する代わりに、サーバーは、サーバーによって提供されるファイルシステムツリーの論理ルートまたは最上位を表すルートファイルハンドルを提供します。サーバーは、疑似ファイルシステムと一緒に接着することにより、複数のファイルシステムを提供します。これらの疑似ファイルシステムは、実際のファイルシステム間のパス名に潜在的なギャップを提供します。 Filehandle Types ファイルハンドルのタイプ

In previous versions of the NFS protocol, the filehandle provided by the server was guaranteed to be valid or persistent for the lifetime of the file system object to which it referred. For some server implementations, this persistence requirement has been difficult to meet. For the NFSv4 protocol, this requirement has been relaxed by introducing another type of filehandle -- volatile. With persistent and volatile filehandle types, the server implementation can match the abilities of the file system at the server along with the operating environment. The client will have knowledge of the type of filehandle being provided by the server and can be prepared to deal with the semantics of each.

以前のバージョンのNFSプロトコルでは、サーバーが提供するファイルハンドルは、それが参照するファイルシステムオブジェクトの存続期間中、有効または永続的であることが保証されていました。一部のサーバー実装では、この永続性要件を満たすのが困難でした。 NFSv4プロトコルの場合、この要件は、別のタイプのファイルハンドル-揮発性-を導入することで緩和されました。永続的で揮発性のファイルハンドルタイプを使用すると、サーバーの実装は、サーバーのファイルシステムの機能と動作環境を一致させることができます。クライアントは、サーバーによって提供されるファイルハンドルのタイプの知識を持ち、それぞれのセマンティクスを処理する準備ができます。 Attribute Types 属性タイプ

The NFSv4 protocol has a rich and extensible file object attribute structure, which is divided into REQUIRED, RECOMMENDED, and named attributes (see Section 5).


Several (but not all) of the REQUIRED attributes are derived from the attributes of NFSv3 (see the definition of the fattr3 data type in [RFC1813]). An example of a REQUIRED attribute is the file object's type (Section so that regular files can be distinguished from directories (also known as folders in some operating environments) and other types of objects. REQUIRED attributes are discussed in Section 5.1.

必須(すべてではない)のいくつかの属性は、NFSv3の属性から派生しています([RFC1813]のfattr3データ型の定義を参照してください)。 REQUIRED属性の例は、ファイルオブジェクトのタイプ(項)です。これにより、通常のファイルをディレクトリ(一部の動作環境ではフォルダとも呼ばれます)や他のタイプのオブジェクトと区別できます。必須属性については、セクション5.1で説明します。

An example of the RECOMMENDED attributes is an acl (Section 6.2.1). This attribute defines an Access Control List (ACL) on a file object. An ACL provides file access control beyond the model used in NFSv3. The ACL definition allows for specification of specific sets of permissions for individual users and groups. In addition, ACL inheritance allows propagation of access permissions and restriction down a directory tree as file system objects are created. RECOMMENDED attributes are discussed in Section 5.2.

RECOMMENDED属性の例はaclです(セクション6.2.1)。この属性は、ファイルオブジェクトのアクセス制御リスト(ACL)を定義します。 ACLは、NFSv3で使用されるモデルを超えたファイルアクセス制御を提供します。 ACL定義では、個々のユーザーとグループに特定の権限セットを指定できます。さらに、ACLの継承により、ファイルシステムオブジェクトが作成されるときに、ディレクトリツリーの下にアクセス許可と制限を伝達できます。推奨される属性については、セクション5.2で説明します。

A named attribute is an opaque byte stream that is associated with a directory or file and referred to by a string name. Named attributes are meant to be used by client applications as a method to associate application-specific data with a regular file or directory. NFSv4.1 modifies named attributes relative to NFSv4.0 by tightening the allowed operations in order to prevent the development of non-interoperable implementations. Named attributes are discussed in Section 5.3.

名前付き属性は、ディレクトリまたはファイルに関連付けられ、文字列名で参照される不透明なバイトストリームです。名前付き属性は、アプリケーション固有のデータを通常のファイルまたはディレクトリに関連付ける方法としてクライアントアプリケーションによって使用されることを意図しています。 NFSv4.1は、相互運用性のない実装の開発を防ぐために、許可される操作を厳しくすることにより、NFSv4.0に関連する名前付き属性を変更します。名前付き属性については、セクション5.3で説明します。 Multi-Server Namespace マルチサーバー名前空間

A single-server namespace is the file system hierarchy that the server presents for remote access. It is a proper subset of all the file systems available locally. NFSv4 contains a number of features to allow implementation of namespaces that cross server boundaries and that allow and facilitate a non-disruptive transfer of support for individual file systems between servers. They are all based upon attributes that allow one file system to specify alternative or new locations for that file system. That is, just as a client might traverse across local file systems on a single server, it can now traverse to a remote file system on a different server.

単一サーバーの名前空間は、サーバーがリモートアクセスのために提示するファイルシステム階層です。ローカルで利用可能なすべてのファイルシステムの適切なサブセットです。 NFSv4には、サーバーの境界を越える名前空間の実装を可能にし、サーバー間の個々のファイルシステムのサポートを無停止で転送できるようにする多数の機能が含まれています。これらはすべて、1つのファイルシステムがそのファイルシステムの代替または新しい場所を指定できるようにする属性に基づいています。つまり、クライアントが単一のサーバー上のローカルファイルシステムを横断するように、クライアントは別のサーバー上のリモートファイルシステムを横断することができます。

These attributes may be used together with the concept of absent file systems, which provide specifications for additional locations but no actual file system content. This allows a number of important facilities:


o Location attributes may be used with absent file systems to implement referrals whereby one server may direct the client to a file system provided by another server. This allows extensive multi-server namespaces to be constructed.

o ロケーション属性は、存在しないファイルシステムで使用して紹介を実装することができます。これにより、あるサーバーが別のサーバーが提供するファイルシステムにクライアントを誘導できます。これにより、広範なマルチサーバー名前空間を構築できます。

o Location attributes may be provided for present file systems to provide the locations of alternative file system instances or replicas to be used in the event that the current file system instance becomes unavailable.

o 現在のファイルシステムインスタンスが使用できなくなった場合に使用される代替ファイルシステムインスタンスまたはレプリカの場所を提供するために、現在のファイルシステムに場所属性を提供できます。

o Location attributes may be provided when a previously present file system becomes absent. This allows non-disruptive migration of file systems to alternative servers.

o 以前に存在していたファイルシステムが存在しなくなったときに、場所属性が提供される場合があります。これにより、ファイルシステムを無停止で代替サーバーに移行できます。

1.4.4. OPEN and CLOSE
1.4.4. 開くと閉じる

The NFSv4 protocol introduces OPEN and CLOSE operations. The OPEN operation provides a single point where file lookup, creation, and share semantics (see Section 9.9) can be combined. The CLOSE operation also provides for the release of state accumulated by OPEN.

NFSv4プロトコルでは、OPENおよびCLOSE操作が導入されています。 OPEN操作は、ファイルの検索、作成、および共有のセマンティクス(セクション9.9を参照)を組み合わせることができる単一のポイントを提供します。 CLOSE操作は、OPENによって蓄積された状態の解放も提供します。

1.4.5. File Locking
1.4.5. ファイルのロック

With the NFSv4 protocol, the support for byte-range file locking is part of the NFS protocol. The file locking support is structured so that an RPC callback mechanism is not required. This is a departure from the previous versions of the NFS file locking protocol, Network Lock Manager (NLM) [RFC1813]. The state associated with file locks is maintained at the server under a lease-based model. The server defines a single lease period for all state held by an NFS client.

NFSv4プロトコルでは、バイト範囲のファイルロックのサポートはNFSプロトコルの一部です。ファイルロックのサポートは、RPCコールバックメカニズムが不要になるように構造化されています。これは、NFSファイルロックプロトコルの以前のバージョン、Network Lock Manager(NLM)[RFC1813]からの逸脱です。ファイルロックに関連付けられた状態は、リースベースのモデルの下でサーバーで維持されます。サーバーは、NFSクライアントが保持するすべての状態に対して単一のリース期間を定義します。

If the client does not renew its lease within the defined period, all state associated with the client's lease may be released by the server. The client may renew its lease by use of the RENEW operation or implicitly by use of other operations (primarily READ).


1.4.6. Client Caching and Delegation
1.4.6. クライアントのキャッシュと委任

The file, attribute, and directory caching for the NFSv4 protocol is similar to previous versions. Attributes and directory information are cached for a duration determined by the client. At the end of a predefined timeout, the client will query the server to see if the related file system object has been updated.


For file data, the client checks its cache validity when the file is opened. A query is sent to the server to determine if the file has been changed. Based on this information, the client determines if the data cache for the file should be kept or released. Also, when the file is closed, any modified data is written to the server.


If an application wants to serialize access to file data, file locking of the file data ranges in question should be used.


The major addition to NFSv4 in the area of caching is the ability of the server to delegate certain responsibilities to the client. When the server grants a delegation for a file to a client, the client is guaranteed certain semantics with respect to the sharing of that file with other clients. At OPEN, the server may provide the client either a read (OPEN_DELEGATE_READ) or a write (OPEN_DELEGATE_WRITE) delegation for the file (see Section 10.4). If the client is granted an OPEN_DELEGATE_READ delegation, it is assured that no other client has the ability to write to the file for the duration of the delegation. If the client is granted an OPEN_DELEGATE_WRITE delegation, the client is assured that no other client has read or write access to the file.

キャッシングの領域でNFSv4に追加された主な点は、サーバーが特定の責任をクライアントに委任する機能です。サーバーがクライアントにファイルの委任を許可すると、クライアントは他のクライアントとのそのファイルの共有に関して特定のセマンティクスが保証されます。 OPENでは、サーバーはクライアントにファイルの読み取り(OPEN_DELEGATE_READ)または書き込み(OPEN_DELEGATE_WRITE)委任を提供します(セクション10.4を参照)。クライアントにOPEN_DELEGATE_READ委任が付与されている場合、委任の間、他のクライアントがファイルに書き込むことができないことが保証されます。クライアントにOPEN_DELEGATE_WRITE委譲が許可されている場合、クライアントは、他のクライアントがファイルへの読み取りまたは書き込みアクセス権を持たないことが保証されます。

Delegations can be recalled by the server. If another client requests access to the file in such a way that the access conflicts with the granted delegation, the server is able to notify the initial client and recall the delegation. This requires that a callback path exist between the server and client. If this callback path does not exist, then delegations cannot be granted. The essence of a delegation is that it allows the client to locally service operations such as OPEN, CLOSE, LOCK, LOCKU, READ, or WRITE without immediate interaction with the server.


1.5. General Definitions
1.5. 一般的な定義

The following definitions are provided for the purpose of providing an appropriate context for the reader.


Absent File System: A file system is "absent" when a namespace component does not have a backing file system.


Anonymous Stateid: The Anonymous Stateid is a special locking object and is defined in Section


Byte: In this document, a byte is an octet, i.e., a datum exactly 8 bits in length.


Client: The client is the entity that accesses the NFS server's resources. The client may be an application that contains the logic to access the NFS server directly. The client may also be the traditional operating system client that provides remote file system services for a set of applications.


With reference to byte-range locking, the client is also the entity that maintains a set of locks on behalf of one or more applications. This client is responsible for crash or failure recovery for those locks it manages.


Note that multiple clients may share the same transport and connection, and multiple clients may exist on the same network node.


Client ID: The client ID is a 64-bit quantity used as a unique, shorthand reference to a client-supplied verifier and ID. The server is responsible for supplying the client ID.


File System: The file system is the collection of objects on a server that share the same fsid attribute (see Section


Lease: A lease is an interval of time defined by the server for which the client is irrevocably granted a lock. At the end of a lease period the lock may be revoked if the lease has not been extended. The lock must be revoked if a conflicting lock has been granted after the lease interval.


All leases granted by a server have the same fixed duration. Note that the fixed interval duration was chosen to alleviate the expense a server would have in maintaining state about variable-length leases across server failures.


Lock: The term "lock" is used to refer to record (byte-range) locks as well as share reservations unless specifically stated otherwise.


Lock-Owner: Each byte-range lock is associated with a specific lock-owner and an open-owner. The lock-owner consists of a client ID and an opaque owner string. The client presents this to the server to establish the ownership of the byte-range lock as needed.


Open-Owner: Each open file is associated with a specific open-owner, which consists of a client ID and an opaque owner string. The client presents this to the server to establish the ownership of the open as needed.


READ Bypass Stateid: The READ Bypass Stateid is a special locking object and is defined in Section

READ Bypass Stateid:READ Bypass Stateidは特別なロックオブジェクトであり、セクション9.1.4.3で定義されています。

Server: The "server" is the entity responsible for coordinating client access to a set of file systems.


Stable Storage: NFSv4 servers must be able to recover without data loss from multiple power failures (including cascading power failures, that is, several power failures in quick succession), operating system failures, and hardware failure of components other than the storage medium itself (for example, disk, non-volatile RAM).


Some examples of stable storage that are allowable for an NFS server include:


(1) Media commit of data. That is, the modified data has been successfully written to the disk media -- for example, the disk platter.


(2) An immediate reply disk drive with battery-backed on-drive intermediate storage or uninterruptible power system (UPS).


(3) Server commit of data with battery-backed intermediate storage and recovery software.


(4) Cache commit with UPS and recovery software.


Stateid: A stateid is a 128-bit quantity returned by a server that uniquely identifies the open and locking states provided by the server for a specific open-owner or lock-owner/open-owner pair for a specific file and type of lock.


Verifier: A verifier is a 64-bit quantity generated by the client that the server can use to determine if the client has restarted and lost all previous lock state.


1.6. Changes since RFC 3530
1.6. RFC 3530以降の変更

The main changes from RFC 3530 [RFC3530] are:

RFC 3530 [RFC3530]からの主な変更点は次のとおりです。

o The XDR definition has been moved to a companion document [RFC7531].

o XDR定義は、関連ドキュメント[RFC7531]に移動されました。

o The IETF intellectual property statements were updated to the latest version.

o IETFの知的財産に関する声明が最新バージョンに更新されました。

o There is a restructured and more complete explanation of multi-server namespace features.

o マルチサーバー名前空間機能の再構成されたより完全な説明があります。

o The handling of domain names was updated to reflect Internationalized Domain Names in Applications (IDNA) [RFC5891].

o ドメイン名の処理が更新され、アプリケーションにおける国際化ドメイン名(IDNA)[RFC5891]が反映されました。

o The previously required LIPKEY and SPKM-3 security mechanisms have been removed.

o 以前は必要だったLIPKEYおよびSPKM-3セキュリティメカニズムが削除されました。

o Some clarification was provided regarding a client re-establishing callback information to the new server if state has been migrated.

o 状態が移行された場合にクライアントが新しいサーバーへのコールバック情報を再確立することに関して、いくつかの説明が提供されました。

o A third edge case was added for courtesy locks and network partitions.

o 3番目のエッジケースは、礼儀ロックおよびネットワークパーティション用に追加されました。

o The definition of stateid was strengthened.

o stateidの定義が強化されました。

1.7. Changes between RFC 3010 and RFC 3530
1.7. RFC 3010とRFC 3530の間の変更

The definition of the NFSv4 protocol in [RFC3530] replaced and obsoleted the definition present in [RFC3010]. While portions of the two documents remained the same, there were substantive changes in others. The changes made between [RFC3010] and [RFC3530] reflect implementation experience and further review of the protocol.

[RFC3530]のNFSv4プロトコルの定義は、[RFC3010]にある定義に取って代わり、廃止されました。 2つのドキュメントの一部は同じままでしたが、他のドキュメントには実質的な変更がありました。 [RFC3010]と[RFC3530]の間で行われた変更は、実装の経験とプロトコルのさらなるレビューを反映しています。

The following list is not inclusive of all changes but presents some of the most notable changes or additions made:


o The state model has added an open_owner4 identifier. This was done to accommodate POSIX-based clients and the model they use for file locking. For POSIX clients, an open_owner4 would correspond to a file descriptor potentially shared amongst a set of processes and the lock_owner4 identifier would correspond to a process that is locking a file.

o 状態モデルにopen_owner4識別子が追加されました。これは、POSIXベースのクライアントとファイルロックに使用するモデルに対応するために行われました。 POSIXクライアントの場合、open_owner4は一連のプロセス間で共有される可能性のあるファイル記述子に対応し、lock_owner4識別子はファイルをロックしているプロセスに対応します。

o Added clarifications and error conditions for the handling of the owner and group attributes. Since these attributes are string based (as opposed to the numeric uid/gid of previous versions of NFS), translations may not be available and hence the changes made.

o 所有者とグループの属性の処理に関する説明とエラー条件が追加されました。これらの属性は(以前のバージョンのNFSの数値のuid / gidとは対照的に)文字列ベースであるため、変換が利用できず、変更が行われる可能性があります。

o Added clarifications for the ACL and mode attributes to address evaluation and partial support.

o 評価と部分的なサポートに対処するために、ACLおよびモード属性の説明が追加されました。

o For identifiers that are defined as XDR opaque, set limits on their size.

o XDR不透明として定義されている識別子の場合、サイズに制限を設定します。

o Added the mounted_on_fileid attribute to allow POSIX clients to correctly construct local mounts.

o POSIXクライアントがローカルマウントを正しく構築できるように、mounted_on_fileid属性を追加しました。

o Modified the SETCLIENTID/SETCLIENTID_CONFIRM operations to deal correctly with confirmation details along with adding the ability to specify new client callback information. Also added clarification of the callback information itself.

o SETCLIENTID / SETCLIENTID_CONFIRM操作を変更し、確認の詳細を正しく処理するとともに、新しいクライアントコールバック情報を指定する機能を追加しました。コールバック情報自体の説明も追加されました。

o Added a new operation RELEASE_LOCKOWNER to enable notifying the server that a lock_owner4 will no longer be used by the client.

o 新しい操作RELEASE_LOCKOWNERが追加され、lock_owner4がクライアントによって使用されなくなることをサーバーに通知できるようになりました。

o Added RENEW operation changes to identify the client correctly and allow for additional error returns.

o クライアントを正しく識別し、追加のエラーが返されるようにするRENEWオペレーションの変更を追加しました。

o Verified error return possibilities for all operations.

o すべての操作でエラーが返される可能性を確認しました。

o Removed use of the pathname4 data type from LOOKUP and OPEN in favor of having the client construct a sequence of LOOKUP operations to achieve the same effect.

o クライアントが一連のLOOKUP操作を構築して同じ効果を得るようにして、LOOKUPおよびOPENからpathname4データ型の使用を削除しました。

2. Protocol Data Types
2. プロトコルデータタイプ

The syntax and semantics to describe the data types of the NFSv4 protocol are defined in the XDR [RFC4506] and RPC [RFC5531] documents. The next sections build upon the XDR data types to define types and structures specific to this protocol. As a reminder, the size constants and authoritative definitions can be found in [RFC7531].

NFSv4プロトコルのデータ型を記述するための構文とセマンティクスは、XDR [RFC4506]およびRPC [RFC5531]ドキュメントで定義されています。次のセクションでは、XDRデータ型に基づいて、このプロトコルに固有の型と構造を定義します。注意として、サイズ定数と信頼できる定義は[RFC7531]にあります。

2.1. Basic Data Types
2.1. 基本的なデータ型

Table 1 lists the base NFSv4 data types.


   | Data Type       | Definition                                      |
   | int32_t         | typedef int int32_t;                            |
   |                 |                                                 |
   | uint32_t        | typedef unsigned int uint32_t;                  |
   |                 |                                                 |
   | int64_t         | typedef hyper int64_t;                          |
   |                 |                                                 |
   | uint64_t        | typedef unsigned hyper uint64_t;                |
   |                 |                                                 |
   | attrlist4       | typedef opaque attrlist4<>;                     |
   |                 |                                                 |
   |                 | Used for file/directory attributes.             |
   |                 |                                                 |
   | bitmap4         | typedef uint32_t bitmap4<>;                     |
   |                 |                                                 |
   |                 | Used in attribute array encoding.               |
   |                 |                                                 |
   | changeid4       | typedef uint64_t changeid4;                     |
   |                 |                                                 |
   |                 | Used in the definition of change_info4.         |
   |                 |                                                 |
   | clientid4       | typedef uint64_t clientid4;                     |
   |                 |                                                 |
   |                 | Shorthand reference to client identification.   |
   |                 |                                                 |
   | count4          | typedef uint32_t count4;                        |
   |                 |                                                 |
   |                 | Various count parameters (READ, WRITE, COMMIT). |
   |                 |                                                 |
   | length4         | typedef uint64_t length4;                       |
   |                 |                                                 |
   |                 | Describes LOCK lengths.                         |
   |                 |                                                 |
   | mode4           | typedef uint32_t mode4;                         |
   |                 |                                                 |
   |                 | Mode attribute data type.                       |
   |                 |                                                 |
   | nfs_cookie4     | typedef uint64_t nfs_cookie4;                   |
   |                 |                                                 |
   |                 | Opaque cookie value for READDIR.                |
   |                 |                                                 |
   | nfs_fh4         | typedef opaque nfs_fh4<NFS4_FHSIZE>;            |
   |                 |                                                 |
   |                 | Filehandle definition.                          |
   |                 |                                                 |
   | nfs_ftype4      | enum nfs_ftype4;                                |
   |                 |                                                 |
   |                 | Various defined file types.                     |
   |                 |                                                 |
   | nfsstat4        | enum nfsstat4;                                  |
   |                 |                                                 |
   |                 | Return value for operations.                    |
   |                 |                                                 |
   | nfs_lease4      | typedef uint32_t nfs_lease4;                    |
   |                 |                                                 |
   |                 | Duration of a lease in seconds.                 |
   |                 |                                                 |
   | offset4         | typedef uint64_t offset4;                       |
   |                 |                                                 |
   |                 | Various offset designations (READ, WRITE, LOCK, |
   |                 | COMMIT).                                        |
   |                 |                                                 |
   | qop4            | typedef uint32_t qop4;                          |
   |                 |                                                 |
   |                 | Quality of protection designation in SECINFO.   |
   |                 |                                                 |
   | sec_oid4        | typedef opaque sec_oid4<>;                      |
   |                 |                                                 |
   |                 | Security Object Identifier.  The sec_oid4 data  |
   |                 | type is not really opaque.  Instead, it         |
   |                 | contains an ASN.1 OBJECT IDENTIFIER as used by  |
   |                 | GSS-API in the mech_type argument to            |
   |                 | GSS_Init_sec_context.  See [RFC2743] for        |
   |                 | details.                                        |
   |                 |                                                 |
   | seqid4          | typedef uint32_t seqid4;                        |
   |                 |                                                 |
   |                 | Sequence identifier used for file locking.      |
   |                 |                                                 |
   | utf8string      | typedef opaque utf8string<>;                    |
   |                 |                                                 |
   |                 | UTF-8 encoding for strings.                     |
   |                 |                                                 |
   | utf8str_cis     | typedef utf8string utf8str_cis;                 |
   |                 |                                                 |
   |                 | Case-insensitive UTF-8 string.                  |
   |                 |                                                 |
   | utf8str_cs      | typedef utf8string utf8str_cs;                  |
   |                 |                                                 |
   |                 | Case-sensitive UTF-8 string.                    |
   |                 |                                                 |
   | utf8str_mixed   | typedef utf8string utf8str_mixed;               |
   |                 |                                                 |
   |                 | UTF-8 strings with a case-sensitive prefix and  |
   |                 | a case-insensitive suffix.                      |
   |                 |                                                 |
   | component4      | typedef utf8str_cs component4;                  |
   |                 |                                                 |
   |                 | Represents pathname components.                 |
   |                 |                                                 |
   | linktext4       | typedef opaque linktext4<>;                     |
   |                 |                                                 |
   |                 | Symbolic link contents ("symbolic link" is      |
   |                 | defined in an Open Group [Section 3.372 of Chapter 3 of Base Definitions of The Open Group Base Specifications Issue 7"">openg_symlink]        |
   |                 | standard).                                      |
   |                 |                                                 |
   | ascii_REQUIRED4 | typedef utf8string ascii_REQUIRED4;             |
   |                 |                                                 |
   |                 | String is sent as ASCII and thus is             |
   |                 | automatically UTF-8.                            |
   |                 |                                                 |
   | pathname4       | typedef component4 pathname4<>;                 |
   |                 |                                                 |
   |                 | Represents pathname for fs_locations.           |
   |                 |                                                 |
   | nfs_lockid4     | typedef uint64_t nfs_lockid4;                   |
   |                 |                                                 |
   | verifier4       | typedef opaque verifier4[NFS4_VERIFIER_SIZE];   |
   |                 |                                                 |
   |                 | Verifier used for various operations (COMMIT,   |
   |                 | CREATE, OPEN, READDIR, WRITE)                   |
   |                 | NFS4_VERIFIER_SIZE is defined as 8.             |

Table 1: Base NFSv4 Data Types


2.2. Structured Data Types
2.2. 構造化データタイプ
2.2.1. nfstime4
2.2.1. nfstime4
   struct nfstime4 {
           int64_t         seconds;
           uint32_t        nseconds;

The nfstime4 structure gives the number of seconds and nanoseconds since midnight or 0 hour January 1, 1970 Coordinated Universal Time (UTC). Values greater than zero for the seconds field denote dates after the 0 hour January 1, 1970. Values less than zero for the seconds field denote dates before the 0 hour January 1, 1970. In both cases, the nseconds field is to be added to the seconds field for the final time representation. For example, if the time to be represented is one-half second before 0 hour January 1, 1970, the seconds field would have a value of negative one (-1) and the nseconds fields would have a value of one-half second (500000000). Values greater than 999,999,999 for nseconds are considered invalid.

nfstime4構造体は、1970年1月1日午前0時または0時からの秒数およびナノ秒数を示します。協定世界時(UTC)。秒フィールドのゼロより大きい値は、1970年1月1日0時間より後の日付を示します。秒フィールドのゼロより小さい値は、1970年1月1日0時間より前の日付を示します。どちらの場合も、n秒フィールドは、最終時刻表現の秒フィールド。たとえば、表現される時間が1970年1月1日0時間前の0.5秒である場合、秒フィールドの値は負の1(-1)になり、n秒フィールドの値は0.5秒( 500000000)。 n秒の999,999,999より大きい値は無効と見なされます。

This data type is used to pass time and date information. A server converts to and from its local representation of time when processing time values, preserving as much accuracy as possible. If the precision of timestamps stored for a file system object is less than defined, loss of precision can occur. An adjunct time maintenance protocol is recommended to reduce client and server time skew.


2.2.2. time_how4
2.2.2. time_how4
   enum time_how4 {
           SET_TO_SERVER_TIME4 = 0,
           SET_TO_CLIENT_TIME4 = 1
2.2.3. settime4
2.2.3. 第7 4
   union settime4 switch (time_how4 set_it) {
            nfstime4       time;

The above definitions are used as the attribute definitions to set time values. If set_it is SET_TO_SERVER_TIME4, then the server uses its local representation of time for the time value.

上記の定義は、時間値を設定するための属性定義として使用されます。 set_itがSET_TO_SERVER_TIME4の場合、サーバーは時間の値としてローカルの時間表現を使用します。

2.2.4. specdata4
2.2.4. specdata4
   struct specdata4 {
           uint32_t specdata1; /* major device number */
           uint32_t specdata2; /* minor device number */

This data type represents additional information for the device file types NF4CHR and NF4BLK.


2.2.5. fsid4
2.2.5. fsid4
   struct fsid4 {
           uint64_t        major;
           uint64_t        minor;

This type is the file system identifier that is used as a REQUIRED attribute.


2.2.6. fs_location4
2.2.6. fs_location4
   struct fs_location4 {
           utf8str_cis             server<>;
           pathname4               rootpath;
2.2.7. fs_locations4
2.2.7. fs_locations4
   struct fs_locations4 {
           pathname4       fs_root;
           fs_location4    locations<>;

The fs_location4 and fs_locations4 data types are used for the fs_locations RECOMMENDED attribute, which is used for migration and replication support.

fs_location4およびfs_locations4データ型は、移行およびレプリケーションのサポートに使用されるfs_locations RECOMMENDED属性に使用されます。

2.2.8. fattr4
2.2.8. fattr4
   struct fattr4 {
           bitmap4         attrmask;
           attrlist4       attr_vals;

The fattr4 structure is used to represent file and directory attributes.


The bitmap is a counted array of 32-bit integers used to contain bit values. The position of the integer in the array that contains bit n can be computed from the expression (n / 32), and its bit within that integer is (n mod 32).

ビットマップは、ビット値を含めるために使用される32ビット整数のカウントされた配列です。ビットnを含む配列内の整数の位置は、式(n / 32)から計算でき、その整数内のビットは(n mod 32)です。

                       0            1
     |  count    | 31  ..  0 | 63  .. 32 |
2.2.9. change_info4
2.2.9. change_info4
   struct change_info4 {
           bool            atomic;
           changeid4       before;
           changeid4       after;

This structure is used with the CREATE, LINK, REMOVE, and RENAME operations to let the client know the value of the change attribute for the directory in which the target file system object resides.


2.2.10. clientaddr4
2.2.10. clientaddr4
   struct clientaddr4 {
           /* see struct rpcb in RFC 1833 */
           string r_netid<>;    /* network id */
           string r_addr<>;     /* universal address */

The clientaddr4 structure is used as part of the SETCLIENTID operation, either (1) to specify the address of the client that is using a client ID or (2) as part of the callback registration. The r_netid and r_addr fields respectively contain a network id and universal address. The network id and universal address concepts, together with formats for TCP over IPv4 and TCP over IPv6, are defined in [RFC5665], specifically Tables 2 and 3 and Sections and

clientaddr4構造体は、SETCLIENTID操作の一部として使用されます。(1)クライアントIDを使用しているクライアントのアドレスを指定するか、(2)コールバック登録の一部として使用されます。 r_netidフィールドとr_addrフィールドには、それぞれネットワークIDとユニバーサルアドレスが含まれています。ネットワークIDとユニバーサルアドレスの概念、およびTCP over IPv4とTCP over IPv6の形式は、[RFC5665]、具体的には表2と3、およびセクション5.2.3.3と5.2.3.4で定義されています。

2.2.11. cb_client4
2.2.11. cb_client4
   struct cb_client4 {
           unsigned int    cb_program;
           clientaddr4     cb_location;

This structure is used by the client to inform the server of its callback address; it includes the program number and client address.


2.2.12. nfs_client_id4
2.2.12. nfs_client_id4
   struct nfs_client_id4 {
           verifier4       verifier;
           opaque          id<NFS4_OPAQUE_LIMIT>;

This structure is part of the arguments to the SETCLIENTID operation.


2.2.13. open_owner4
2.2.13. open_owner4
   struct open_owner4 {
           clientid4       clientid;
           opaque          owner<NFS4_OPAQUE_LIMIT>;

This structure is used to identify the owner of open state.


2.2.14. lock_owner4
2.2.14. lock_owner4
   struct lock_owner4 {
           clientid4       clientid;
           opaque          owner<NFS4_OPAQUE_LIMIT>;

This structure is used to identify the owner of file locking state.


2.2.15. open_to_lock_owner4
2.2.15. open_to_lock_owner4
   struct open_to_lock_owner4 {
           seqid4          open_seqid;
           stateid4        open_stateid;
           seqid4          lock_seqid;
           lock_owner4     lock_owner;

This structure is used for the first LOCK operation done for an open_owner4. It provides both the open_stateid and lock_owner such that the transition is made from a valid open_stateid sequence to that of the new lock_stateid sequence. Using this mechanism avoids the confirmation of the lock_owner/lock_seqid pair since it is tied to established state in the form of the open_stateid/open_seqid.

この構造は、open_owner4に対して行われる最初のLOCK操作に使用されます。有効なopen_stateidシーケンスから新しいlock_stateidシーケンスへの移行が行われるように、open_stateidとlock_ownerの両方を提供します。このメカニズムを使用すると、open_stateid / open_seqidの形式で確立された状態に関連付けられるため、lock_owner / lock_seqidペアの確認が回避されます。

2.2.16. stateid4
2.2.16. stateid4
   struct stateid4 {
           uint32_t        seqid;
           opaque          other[NFS4_OTHER_SIZE];

This structure is used for the various state-sharing mechanisms between the client and server. For the client, this data structure is read-only. The server is required to increment the seqid field monotonically at each transition of the stateid. This is important since the client will inspect the seqid in OPEN stateids to determine the order of OPEN processing done by the server.


3. RPC and Security Flavor
3. RPCとセキュリティの味

The NFSv4 protocol is an RPC application that uses RPC version 2 and the XDR as defined in [RFC5531] and [RFC4506]. The RPCSEC_GSS security flavors as defined in version 1 ([RFC2203]) and version 2 ([RFC5403]) MUST be implemented as the mechanism to deliver stronger security for the NFSv4 protocol. However, deployment of RPCSEC_GSS is optional.


3.1. Ports and Transports
3.1. ポートとトランスポート

Historically, NFSv2 and NFSv3 servers have resided on port 2049. The registered port 2049 [RFC3232] for the NFS protocol SHOULD be the default configuration. Using the registered port for NFS services means the NFS client will not need to use the RPC binding protocols as described in [RFC1833]; this will allow NFS to transit firewalls.

歴史的に、NFSv2およびNFSv3サーバーはポート2049に常駐していました。NFSプロトコル用の登録済みポート2049 [RFC3232]は、デフォルトの構成である必要があります(SHOULD)。 NFSサービスに登録されたポートを使用することは、[RFC1833]で説明されているように、NFSクライアントがRPCバインディングプロトコルを使用する必要がないことを意味します。これにより、NFSがファイアウォールを通過できるようになります。

Where an NFSv4 implementation supports operation over the IP network protocol, the supported transport layer between NFS and IP MUST be an IETF standardized transport protocol that is specified to avoid network congestion; such transports include TCP and the Stream Control Transmission Protocol (SCTP). To enhance the possibilities for interoperability, an NFSv4 implementation MUST support operation over the TCP transport protocol.

NFSv4実装がIPネットワークプロトコルでの動作をサポートする場合、NFSとIPの間でサポートされるトランスポート層は、ネットワークの輻輳を回避するために指定されたIETF標準トランスポートプロトコルでなければなりません。このようなトランスポートには、TCPおよびStream Control Transmission Protocol(SCTP)が含まれます。相互運用性の可能性を高めるために、NFSv4実装は、TCPトランスポートプロトコルを介した操作をサポートする必要があります。

If TCP is used as the transport, the client and server SHOULD use persistent connections. This will prevent the weakening of TCP's congestion control via short-lived connections and will improve performance for the Wide Area Network (WAN) environment by eliminating the need for SYN handshakes.


As noted in Section 19, the authentication model for NFSv4 has moved from machine-based to principal-based. However, this modification of the authentication model does not imply a technical requirement to move the TCP connection management model from whole machine-based to one based on a per-user model. In particular, NFS over TCP client implementations have traditionally multiplexed traffic for multiple users over a common TCP connection between an NFS client and server. This has been true, regardless of whether the NFS client is using AUTH_SYS, AUTH_DH, RPCSEC_GSS, or any other flavor. Similarly, NFS over TCP server implementations have assumed such a model and thus scale the implementation of TCP connection management in proportion to the number of expected client machines. It is intended that NFSv4 will not modify this connection management model. NFSv4 clients that violate this assumption can expect scaling issues on the server and hence reduced service.

セクション19で述べたように、NFSv4の認証モデルは、マシンベースからプリンシパルベースに移行しました。ただし、この認証モデルの変更は、TCP接続管理モデルをマシンベース全体からユーザーごとのモデルに基づくものに移行するための技術的要件を意味するものではありません。特に、NFS over TCPクライアントの実装では、NFSクライアントとサーバー間の共通のTCP接続を介して、複数のユーザーのトラフィックを従来から多重化しています。これは、NFSクライアントがAUTH_SYS、AUTH_DH、RPCSEC_GSS、またはその他のフレーバーを使用しているかどうかに関係なく当てはまります。同様に、NFS over TCPサーバーの実装ではこのようなモデルを想定しているため、TCP接続管理の実装は、予想されるクライアントマシンの数に比例してスケーリングされます。 NFSv4がこの接続管理モデルを変更しないことを意図しています。この仮定に違反するNFSv4クライアントは、サーバーでのスケーリングの問題を予期し、それによりサービスが低下する可能性があります。

3.1.1. Client Retransmission Behavior
3.1.1. クライアントの再送信動作

When processing an NFSv4 request received over a reliable transport such as TCP, the NFSv4 server MUST NOT silently drop the request, except if the established transport connection has been broken. Given such a contract between NFSv4 clients and servers, clients MUST NOT retry a request unless one or both of the following are true:

TCPなどの信頼できるトランスポートを介して受信したNFSv4要求を処理する場合、NFSv4サーバーは、確立されたトランスポート接続が切断されている場合を除いて、要求を黙ってドロップしてはなりません(MUST NOT)。 NFSv4クライアントとサーバーの間でそのような契約が与えられている場合、次のいずれかまたは両方が当てはまらない限り、クライアントは要求を再試行してはなりません(MUST NOT)。

o The transport connection has been broken

o トランスポート接続が切断されました

o The procedure being retried is the NULL procedure

o 再試行中のプロシージャはNULLプロシージャです

Since reliable transports, such as TCP, do not always synchronously inform a peer when the other peer has broken the connection (for example, when an NFS server reboots), the NFSv4 client may want to actively "probe" the connection to see if has been broken. Use of the NULL procedure is one recommended way to do so. So, when a client experiences a remote procedure call timeout (of some arbitrary implementation-specific amount), rather than retrying the remote procedure call, it could instead issue a NULL procedure call to the server. If the server has died, the transport connection break will eventually be indicated to the NFSv4 client. The client can then reconnect, and then retry the original request. If the NULL procedure call gets a response, the connection has not broken. The client can decide to wait longer for the original request's response, or it can break the transport connection and reconnect before re-sending the original request.

TCPなどの信頼性の高いトランスポートは、他のピアが接続を切断したとき(たとえば、NFSサーバーが再起動したとき)に常に同期的にピアに通知するわけではないため、NFSv4クライアントは接続をアクティブに「調査」して、壊れた。 NULLプロシージャの使用は、そのための1つの推奨される方法です。したがって、クライアントがリモートプロシージャコールを再試行するのではなく、リモートプロシージャコールタイムアウト(実装固有の任意の量)が発生した場合、代わりにサーバーにNULLプロシージャコールを発行できます。サーバーが停止すると、トランスポート接続の切断が最終的にNFSv4クライアントに示されます。その後、クライアントは再接続して、元の要求を再試行できます。 NULLプロシージャコールが応答を受け取った場合、接続は切断されていません。クライアントは、元の要求の応答をさらに長く待つか、元の要求を再送信する前にトランスポート接続を切断して再接続するかを決定できます。

For callbacks from the server to the client, the same rules apply, but the server doing the callback becomes the client, and the client receiving the callback becomes the server.


3.2. Security Flavors
3.2. セキュリティフレーバー

Traditional RPC implementations have included AUTH_NONE, AUTH_SYS, AUTH_DH, and AUTH_KRB4 as security flavors. With [RFC2203], an additional security flavor of RPCSEC_GSS has been introduced, which uses the functionality of GSS-API [RFC2743]. This allows for the use of various security mechanisms by the RPC layer without the additional implementation overhead of adding RPC security flavors. For NFSv4, the RPCSEC_GSS security flavor MUST be used to enable the mandatory-to-implement security mechanism. Other flavors, such as AUTH_NONE, AUTH_SYS, and AUTH_DH, MAY be implemented as well.

従来のRPC実装には、セキュリティフレーバーとしてAUTH_NONE、AUTH_SYS、AUTH_DH、AUTH_KRB4が含まれていました。 [RFC2203]で、GSS-API [RFC2743]の機能を使用するRPCSEC_GSSの追加のセキュリティフレーバーが導入されました。これにより、RPCセキュリティフレーバーを追加することによる追加の実装オーバーヘッドなしで、RPCレイヤーによるさまざまなセキュリティメカニズムの使用が可能になります。 NFSv4の場合、RPCSEC_GSSセキュリティフレーバーを使用して、必須から実装までのセキュリティメカニズムを有効にする必要があります。 AUTH_NONE、AUTH_SYS、AUTH_DHなどの他のフレーバーも実装される場合があります。

3.2.1. Security Mechanisms for NFSv4
3.2.1. NFSv4のセキュリティメカニズム

RPCSEC_GSS, via GSS-API, supports multiple mechanisms that provide security services. For interoperability, NFSv4 clients and servers MUST support the Kerberos V5 security mechanism.

RPCSEC_GSSは、GSS-APIを介して、セキュリティサービスを提供する複数のメカニズムをサポートします。相互運用性のために、NFSv4クライアントとサーバーはKerberos V5セキュリティメカニズムをサポートする必要があります。

The use of RPCSEC_GSS requires selection of mechanism, quality of protection (QOP), and service (authentication, integrity, privacy). For the mandated security mechanisms, NFSv4 specifies that a QOP of zero is used, leaving it up to the mechanism or the mechanism's configuration to map QOP zero to an appropriate level of protection. Each mandated mechanism specifies a minimum set of cryptographic algorithms for implementing integrity and privacy. NFSv4 clients and servers MUST be implemented on operating environments that comply with the required cryptographic algorithms of each required mechanism.

RPCSEC_GSSを使用するには、メカニズム、保護品質(QOP)、およびサービス(認証、整合性、プライバシー)を選択する必要があります。必須のセキュリティメカニズムの場合、NFSv4はゼロのQOPが使用されることを指定し、メカニズムまたはメカニズムの構成に任せて、QOPゼロを適切な保護レベルにマップします。各必須メカニズムは、整合性とプライバシーを実装するための暗号化アルゴリズムの最小セットを指定します。 NFSv4クライアントとサーバーは、必要な各メカニズムの必要な暗号化アルゴリズムに準拠する動作環境に実装する必要があります。 Kerberos V5 as a Security Triple セキュリティトリプルとしてのKerberos V5

The Kerberos V5 GSS-API mechanism as described in [RFC4121] MUST be implemented with the RPCSEC_GSS services as specified in Table 2. Both client and server MUST support each of the pseudo-flavors.

[RFC4121]で説明されているKerberos V5 GSS-APIメカニズムは、表2で指定されているRPCSEC_GSSサービスを使用して実装する必要があります。クライアントとサーバーの両方が、それぞれの疑似フレーバーをサポートする必要があります。

     | Number | Name  | Mechanism's OID      | RPCSEC_GSS service    |
     | 390003 | krb5  | 1.2.840.113554.1.2.2 | rpc_gss_svc_none      |
     | 390004 | krb5i | 1.2.840.113554.1.2.2 | rpc_gss_svc_integrity |
     | 390005 | krb5p | 1.2.840.113554.1.2.2 | rpc_gss_svc_privacy   |

Table 2: Mapping Pseudo-Flavor to Service


Note that the pseudo-flavor is presented here as a mapping aid to the implementer. Because this NFS protocol includes a method to negotiate security and it understands the GSS-API mechanism, the pseudo-flavor is not needed. The pseudo-flavor is needed for NFSv3 since the security negotiation is done via the MOUNT protocol as described in [RFC2623].

ここでは、疑似フレーバーが実装者へのマッピング支援として提示されていることに注意してください。このNFSプロトコルには、セキュリティをネゴシエートする方法が含まれており、GSS-APIメカニズムを理解しているため、疑似フレーバーは必要ありません。 [RFC2623]で説明されているように、セキュリティネゴシエーションはMOUNTプロトコルを介して行われるため、NFSv3には疑似フレーバーが必要です。

At the time this document was specified, the Advanced Encryption Standard (AES) with HMAC-SHA1 was a required algorithm set for Kerberos V5. In contrast, when NFSv4.0 was first specified in [RFC3530], weaker algorithm sets were REQUIRED for Kerberos V5, and were REQUIRED in the NFSv4.0 specification, because the Kerberos V5 specification at the time did not specify stronger algorithms. The NFSv4 specification does not specify required algorithms for Kerberos V5, and instead, the implementer is expected to track the evolution of the Kerberos V5 standard if and when stronger algorithms are specified.

このドキュメントが指定された時点では、HMAC-SHA1を使用したAdvanced Encryption Standard(AES)がKerberos V5に必要なアルゴリズムセットでした。対照的に、[RFC3530]でNFSv4.0が最初に指定されたとき、Kerberos V5仕様はより強力なアルゴリズムを指定していなかったため、より弱いアルゴリズムセットはKerberos V5で必須であり、NFSv4.0仕様で必須でした。 NFSv4仕様はKerberos V5に必要なアルゴリズムを指定していません。代わりに、より強力なアルゴリズムが指定されている場合、実装者はKerberos V5標準の進化を追跡することが期待されています。 Security Considerations for Cryptographic Algorithms in Kerberos V5 Kerberos V5の暗号化アルゴリズムのセキュリティに関する考慮事項

When deploying NFSv4, the strength of the security achieved depends on the existing Kerberos V5 infrastructure. The algorithms of Kerberos V5 are not directly exposed to or selectable by the client or server, so there is some due diligence required by the user of NFSv4 to ensure that security is acceptable where needed. Guidance is provided in [RFC6649] as to why weak algorithms should be disabled by default.

NFSv4を導入する場合、達成されるセキュリティの強度は、既存のKerberos V5インフラストラクチャに依存します。 Kerberos V5のアルゴリズムは、クライアントやサーバーに直接公開されたり、選択したりすることはできないため、NFSv4のユーザーは、必要な場所でセキュリティを確実に受け入れるために、ある程度の注意が必要です。 [RFC6649]では、弱いアルゴリズムをデフォルトで無効にする必要がある理由についてのガイダンスが提供されています。

3.3. Security Negotiation
3.3. セキュリティ交渉

With the NFSv4 server potentially offering multiple security mechanisms, the client needs a method to determine or negotiate which mechanism is to be used for its communication with the server. The NFS server can have multiple points within its file system namespace that are available for use by NFS clients. In turn, the NFS server can be configured such that each of these entry points can have different or multiple security mechanisms in use.

NFSv4サーバーは複数のセキュリティメカニズムを提供する可能性があるため、クライアントは、サーバーとの通信に使用するメカニズムを決定またはネゴシエートする方法を必要とします。 NFSサーバーは、NFSクライアントが使用できるファイルシステム名前空間内に複数のポイントを持つことができます。次に、NFSサーバーは、これらの各エントリポイントが異なるセキュリティメカニズムまたは複数のセキュリティメカニズムを使用できるように構成できます。

The security negotiation between client and server SHOULD be done with a secure channel to eliminate the possibility of a third party intercepting the negotiation sequence and forcing the client and server to choose a lower level of security than required or desired. See Section 19 for further discussion.


3.3.1. SECINFO
3.3.1. SECINFO

The SECINFO operation will allow the client to determine, on a per-filehandle basis, what security triple (see [RFC2743] and Section 16.31.4) is to be used for server access. In general, the client will not have to use the SECINFO operation, except during initial communication with the server or when the client encounters a new security policy as the client navigates the namespace. Either condition will force the client to negotiate a new security triple.


3.3.2. Security Error
3.3.2. セキュリティエラー

Based on the assumption that each NFSv4 client and server MUST support a minimum set of security (i.e., Kerberos V5 under RPCSEC_GSS), the NFS client will start its communication with the server with one of the minimal security triples. During communication with the server, the client can receive an NFS error of NFS4ERR_WRONGSEC. This error allows the server to notify the client that the security triple currently being used is not appropriate for access to the server's file system resources. The client is then responsible for determining what security triples are available at the server and choosing one that is appropriate for the client. See Section 16.31 for further discussion of how the client will respond to the NFS4ERR_WRONGSEC error and use SECINFO.

各NFSv4クライアントとサーバーは最小限のセキュリティセット(つまり、RPCSEC_GSSでのKerberos V5)をサポートする必要があるという想定に基づいて、NFSクライアントはサーバーとの通信を最小限のセキュリティトリプルの1つで開始します。サーバーとの通信中に、クライアントはNFS4ERR_WRONGSECのNFSエラーを受け取ることがあります。このエラーにより、サーバーは、現在使用されているセキュリティトリプルがサーバーのファイルシステムリソースへのアクセスに適切でないことをクライアントに通知できます。次に、クライアントは、サーバーで利用可能なセキュリティトリプルを決定し、クライアントに適したものを選択する責任があります。クライアントがNFS4ERR_WRONGSECエラーに応答し、SECINFOを使用する方法の詳細については、セクション16.31を参照してください。

3.3.3. Callback RPC Authentication
3.3.3. コールバックRPC認証

Except as noted elsewhere in this section, the callback RPC (described later) MUST mutually authenticate the NFS server to the principal that acquired the client ID (also described later), using the security flavor of the original SETCLIENTID operation used.


For AUTH_NONE, there are no principals, so this is a non-issue.


AUTH_SYS has no notions of mutual authentication or a server principal, so the callback from the server simply uses the AUTH_SYS credential that the user used when he set up the delegation.


For AUTH_DH, one commonly used convention is that the server uses the credential corresponding to this AUTH_DH principal:



where host and domain are variables corresponding to the name of the server host and directory services domain in which it lives, such as a Network Information System domain or a DNS domain.


Regardless of what security mechanism under RPCSEC_GSS is being used, the NFS server MUST identify itself in GSS-API via a GSS_C_NT_HOSTBASED_SERVICE name type. GSS_C_NT_HOSTBASED_SERVICE names are of the form:

RPCSEC_GSSで使用されているセキュリティメカニズムに関係なく、NFSサーバーはGSS_C_NT_HOSTBASED_SERVICE名前タイプを介してGSS-APIで自身を識別しなければなりません。 GSS_C_NT_HOSTBASED_SERVICEの名前の形式は次のとおりです。


service @ hostname

For NFS, the "service" element is:




Implementations of security mechanisms will convert nfs@hostname to various different forms. For Kerberos V5, the following form is RECOMMENDED:

セキュリティメカニズムを実装すると、nfs @ hostnameがさまざまな形式に変換されます。 Kerberos V5の場合、次の形式が推奨されます。


nfs /ホスト名

For Kerberos V5, nfs/hostname would be a server principal in the Kerberos Key Distribution Center database. This is the same principal the client acquired a GSS-API context for when it issued the SETCLIENTID operation; therefore, the realm name for the server principal must be the same for the callback as it was for the SETCLIENTID.

Kerberos V5の場合、nfs / hostnameはKerberosキー配布センターデータベースのサーバープリンシパルになります。これは、クライアントがSETCLIENTID操作を発行したときにGSS-APIコンテキストを取得したのと同じプリンシパルです。したがって、サーバープリンシパルのレルム名は、SETCLIENTIDの場合と同じである必要があります。

4. Filehandles
4. ファイルハンドル

The filehandle in the NFS protocol is a per-server unique identifier for a file system object. The contents of the filehandle are opaque to the client. Therefore, the server is responsible for translating the filehandle to an internal representation of the file system object.


4.1. Obtaining the First Filehandle
4.1. 最初のファイルハンドルを取得する

The operations of the NFS protocol are defined in terms of one or more filehandles. Therefore, the client needs a filehandle to initiate communication with the server. With the NFSv2 protocol [RFC1094] and the NFSv3 protocol [RFC1813], there exists an ancillary protocol to obtain this first filehandle. The MOUNT protocol, RPC program number 100005, provides the mechanism of translating a string-based file system pathname to a filehandle that can then be used by the NFS protocols.

NFSプロトコルの操作は、1つ以上のファイルハンドルで定義されます。したがって、クライアントはサーバーとの通信を開始するためにファイルハンドルを必要とします。 NFSv2プロトコル[RFC1094]およびNFSv3プロトコル[RFC1813]では、この最初のファイルハンドルを取得するための補助的なプロトコルが存在します。 MOUNTプロトコル、RPCプログラム番号100005は、文字列ベースのファイルシステムパス名を、NFSプロトコルで使用できるファイルハンドルに変換するメカニズムを提供します。

The MOUNT protocol has deficiencies in the area of security and use via firewalls. This is one reason that the use of the public filehandle was introduced in [RFC2054] and [RFC2055]. With the use of the public filehandle in combination with the LOOKUP operation in the NFSv2 and NFSv3 protocols, it has been demonstrated that the MOUNT protocol is unnecessary for viable interaction between the NFS client and server.

MOUNTプロトコルには、セキュリティおよびファイアウォール経由の使用の分野での欠点があります。これは、パブリックファイルハンドルの使用が[RFC2054]と[RFC2055]で導入された1つの理由です。 NFSv2およびNFSv3プロトコルのLOOKUP操作と組み合わせてパブリックファイルハンドルを使用すると、NFSクライアントとサーバー間の実行可能な対話にはMOUNTプロトコルが不要であることが実証されています。

Therefore, the NFSv4 protocol will not use an ancillary protocol for translation from string-based pathnames to a filehandle. Two special filehandles will be used as starting points for the NFS client.

したがって、NFSv4プロトコルは、文字列ベースのパス名からファイルハンドルへの変換に補助プロトコルを使用しません。 NFSクライアントの開始点として、2つの特別なファイルハンドルが使用されます。

4.1.1. Root Filehandle
4.1.1. ルートファイルハンドル

The first of the special filehandles is the root filehandle. The root filehandle is the "conceptual" root of the file system namespace at the NFS server. The client uses or starts with the root filehandle by employing the PUTROOTFH operation. The PUTROOTFH operation instructs the server to set the current filehandle to the root of the server's file tree. Once this PUTROOTFH operation is used, the client can then traverse the entirety of the server's file tree with the LOOKUP operation. A complete discussion of the server namespace is in Section 7.

特別なファイルハンドルの最初のものはルートファイルハンドルです。ルートファイルハンドルは、NFSサーバーでのファイルシステム名前空間の「概念的な」ルートです。クライアントは、PUTROOTFH操作を使用して、ルートファイルハンドルを使用するか、ルートファイルハンドルで開始します。 PUTROOTFH操作は、現在のファイルハンドルをサーバーのファイルツリーのルートに設定するようサーバーに指示します。このPUTROOTFH操作を使用すると、クライアントはLOOKUP操作を使用してサーバーのファイルツリー全体をトラバースできます。サーバーの名前空間の詳細については、セクション7を参照してください。

4.1.2. Public Filehandle
4.1.2. 公開ファイルハンドル

The second special filehandle is the public filehandle. Unlike the root filehandle, the public filehandle may be bound or represent an arbitrary file system object at the server. The server is responsible for this binding. It may be that the public filehandle and the root filehandle refer to the same file system object. However, it is up to the administrative software at the server and the policies of the server administrator to define the binding of the public filehandle and server file system object. The client may not make any assumptions about this binding. The client uses the public filehandle via the PUTPUBFH operation.


4.2. Filehandle Types
4.2. ファイルハンドルのタイプ

In the NFSv2 and NFSv3 protocols, there was one type of filehandle with a single set of semantics, of which the primary one was that it was persistent across a server reboot. As such, this type of filehandle is termed "persistent" in NFSv4. The semantics of a persistent filehandle remain the same as before. A new type of filehandle introduced in NFSv4 is the volatile filehandle, which attempts to accommodate certain server environments.

NFSv2およびNFSv3プロトコルでは、単一のセマンティクスのセットを持つ1種類のファイルハンドルがあり、その主なものはサーバーの再起動後も永続的であるというものでした。そのため、このタイプのファイルハンドルは、NFSv4では「永続的」と呼ばれています。永続ファイルハンドルのセマンティクスは以前と同じままです。 NFSv4で導入された新しいタイプのファイルハンドルは、特定のサーバー環境に対応しようとする揮発性ファイルハンドルです。

The volatile filehandle type was introduced to address server functionality or implementation issues that make correct implementation of a persistent filehandle infeasible. Some server environments do not provide a file system level invariant that can be used to construct a persistent filehandle. The underlying server file system may not provide the invariant, or the server's file system programming interfaces may not provide access to the needed invariant. Volatile filehandles may ease the implementation of server functionality, such as hierarchical storage management or file system reorganization or migration. However, the volatile filehandle increases the implementation burden for the client.


Since the client will need to handle persistent and volatile filehandles differently, a file attribute is defined that may be used by the client to determine the filehandle types being returned by the server.


4.2.1. General Properties of a Filehandle
4.2.1. ファイルハンドルの一般的なプロパティ

The filehandle contains all the information the server needs to distinguish an individual file. To the client, the filehandle is opaque. The client stores filehandles for use in a later request and can compare two filehandles from the same server for equality by doing a byte-by-byte comparison. However, the client MUST NOT otherwise interpret the contents of filehandles. If two filehandles from the same server are equal, they MUST refer to the same file. However, it is not required that two different filehandles refer to different file system objects. Servers SHOULD try to maintain a one-to-one correspondence between filehandles and file system objects but there may be situations in which the mapping is not one-to-one. Clients MUST use filehandle comparisons only to improve performance, not for correct behavior. All clients need to be prepared for situations in which it cannot be determined whether two different filehandles denote the same object and in such cases need to avoid assuming that objects denoted are different, as this might cause incorrect behavior. Further discussion of filehandle and attribute comparison in the context of data caching is presented in Section 10.3.4.

ファイルハンドルには、サーバーが個々のファイルを区別するために必要なすべての情報が含まれています。クライアントにとって、ファイルハンドルは不透明です。クライアントは、後の要求で使用するためにファイルハンドルを格納し、バイトごとの比較を行うことにより、同じサーバーからの2つのファイルハンドルが等しいかどうかを比較できます。ただし、クライアントはファイルハンドルの内容を別の方法で解釈してはなりません(MUST NOT)。同じサーバーからの2つのファイルハンドルが等しい場合、それらは同じファイルを参照する必要があります。ただし、2つの異なるファイルハンドルが異なるファイルシステムオブジェクトを参照する必要はありません。サーバーは、ファイルハンドルとファイルシステムオブジェクト間の1対1の対応を維持する必要がありますが、マッピングが1対1ではない場合があります。クライアントは、正しい動作ではなく、パフォーマンスを向上させるためにのみファイルハンドル比較を使用する必要があります。すべてのクライアントは、2つの異なるファイルハンドルが同じオブジェクトを示しているかどうかを判断できない状況に備える必要があります。その場合、誤った動作を引き起こす可能性があるため、示されているオブジェクトが異なると想定しないようにする必要があります。データキャッシュのコンテキストでのファイルハンドルと属性比較の詳細については、セクション10.3.4で説明します。

As an example, in the case that two different pathnames when traversed at the server terminate at the same file system object, the server SHOULD return the same filehandle for each path. This can occur if a hard link is used to create two filenames that refer to the same underlying file object and associated data. For example, if paths /a/b/c and /a/d/c refer to the same file, the server SHOULD return the same filehandle for both pathname traversals.

例として、サーバーでトラバースしたときに2つの異なるパス名が同じファイルシステムオブジェクトで終了する場合、サーバーは各パスに対して同じファイルハンドルを返す必要があります(SHOULD)。これは、ハードリンクを使用して、同じ基本的なファイルオブジェクトと関連データを参照する2つのファイル名を作成した場合に発生する可能性があります。たとえば、パス/ a / b / cと/ a / d / cが同じファイルを参照している場合、サーバーは両方のパス名トラバーサルに対して同じファイルハンドルを返す必要があります(SHOULD)。

4.2.2. Persistent Filehandle
4.2.2. 永続的なファイルハンドル

A persistent filehandle is defined as having a fixed value for the lifetime of the file system object to which it refers. Once the server creates the filehandle for a file system object, the server MUST accept the same filehandle for the object for the lifetime of the object. If the server restarts or reboots, the NFS server must honor the same filehandle value as it did in the server's previous instantiation. Similarly, if the file system is migrated, the new NFS server must honor the same filehandle as the old NFS server.


The persistent filehandle will become stale or invalid when the file system object is removed. When the server is presented with a persistent filehandle that refers to a deleted object, it MUST return an error of NFS4ERR_STALE. A filehandle may become stale when the file system containing the object is no longer available. The file system may become unavailable if it exists on removable media and the media is no longer available at the server, or if the file system in whole has been destroyed, or if the file system has simply been removed from the server's namespace (i.e., unmounted in a UNIX environment).

永続ファイルハンドルは、ファイルシステムオブジェクトが削除されると、古くなるか無効になります。サーバーが、削除されたオブジェクトを参照する永続的なファイルハンドルを提示されると、NFS4ERR_STALEのエラーを返さなければなりません(MUST)。オブジェクトを含むファイルシステムが使用できなくなると、ファイルハンドルが古くなる場合があります。ファイルシステムがリムーバブルメディアに存在し、メディアがサーバーで使用できなくなった場合、ファイルシステム全体が破壊された場合、またはファイルシステムがサーバーの名前空間から削除された場合(つまり、 UNIX環境ではマウント解除されます)。

4.2.3. Volatile Filehandle
4.2.3. 揮発性ファイルハンドル

A volatile filehandle does not share the same longevity characteristics of a persistent filehandle. The server may determine that a volatile filehandle is no longer valid at many different points in time. If the server can definitively determine that a volatile filehandle refers to an object that has been removed, the server should return NFS4ERR_STALE to the client (as is the case for persistent filehandles). In all other cases where the server determines that a volatile filehandle can no longer be used, it should return an error of NFS4ERR_FHEXPIRED.


The REQUIRED attribute "fh_expire_type" is used by the client to determine what type of filehandle the server is providing for a particular file system. This attribute is a bitmask with the following values:


FH4_PERSISTENT: The value of FH4_PERSISTENT is used to indicate a persistent filehandle, which is valid until the object is removed from the file system. The server will not return NFS4ERR_FHEXPIRED for this filehandle. FH4_PERSISTENT is defined as a value in which none of the bits specified below are set.

FH4_PERSISTENT:FH4_PERSISTENTの値は、オブジェクトがファイルシステムから削除されるまで有効な永続的なファイルハンドルを示すために使用されます。サーバーは、このファイルハンドルに対してNFS4ERR_FHEXPIREDを返しません。 FH4_PERSISTENTは、以下に指定されたビットが設定されていない値として定義されます。

FH4_VOLATILE_ANY: The filehandle may expire at any time, except as specifically excluded (i.e., FH4_NOEXPIRE_WITH_OPEN).


FH4_NOEXPIRE_WITH_OPEN: May only be set when FH4_VOLATILE_ANY is set. If this bit is set, then the meaning of FH4_VOLATILE_ANY is qualified to exclude any expiration of the filehandle when it is open.


FH4_VOL_MIGRATION: The filehandle will expire as a result of migration. If FH4_VOLATILE_ANY is set, FH4_VOL_MIGRATION is redundant.

FH4_VOL_MIGRATION:移行の結果としてファイルハンドルが期限切れになります。 FH4_VOLATILE_ANYが設定されている場合、FH4_VOL_MIGRATIONは冗長です。

FH4_VOL_RENAME: The filehandle will expire during rename. This includes a rename by the requesting client or a rename by any other client. If FH4_VOLATILE_ANY is set, FH4_VOL_RENAME is redundant.

FH4_VOL_RENAME:ファイルハンドルは名前変更中に期限切れになります。これには、要求元クライアントによる名前変更、または他のクライアントによる名前変更が含まれます。 FH4_VOLATILE_ANYが設定されている場合、FH4_VOL_RENAMEは冗長です。

Servers that provide volatile filehandles that may expire while open (i.e., if FH4_VOL_MIGRATION or FH4_VOL_RENAME is set or if FH4_VOLATILE_ANY is set and FH4_NOEXPIRE_WITH_OPEN is not set) should deny a RENAME or REMOVE that would affect an OPEN file of any of the components leading to the OPEN file. In addition, the server SHOULD deny all RENAME or REMOVE requests during the grace period upon server restart.


Note that the bits FH4_VOL_MIGRATION and FH4_VOL_RENAME allow the client to determine that expiration has occurred whenever a specific event occurs, without an explicit filehandle expiration error from the server. FH4_VOLATILE_ANY does not provide this form of information. In situations where the server will expire many, but not all, filehandles upon migration (e.g., all but those that are open), FH4_VOLATILE_ANY (in this case, with FH4_NOEXPIRE_WITH_OPEN) is a better choice since the client may not assume that all filehandles will expire when migration occurs, and it is likely that additional expirations will occur (as a result of file CLOSE) that are separated in time from the migration event itself.

FH4_VOL_MIGRATIONビットとFH4_VOL_RENAMEビットを使用すると、クライアントは、サーバーからの明示的なファイルハンドル有効期限エラーなしで、特定のイベントが発生するたびに有効期限が発生したと判断できます。 FH4_VOLATILE_ANYは、この形式の情報を提供しません。サーバーが移行時にすべてではなく多くのファイルハンドル(たとえば、開いているものを除く)を期限切れにする状況では、FH4_VOLATILE_ANY(この場合、FH4_NOEXPIRE_WITH_OPENを使用)は、クライアントがすべてのファイルハンドルが移行が発生すると期限切れになり、移行イベント自体から時間的に分離された(ファイルのCLOSEの結果として)追加の期限切れが発生する可能性があります。

4.2.4. One Method of Constructing a Volatile Filehandle
4.2.4. 揮発性ファイルハンドルを構築する1つの方法

A volatile filehandle, while opaque to the client, could contain:


[volatile bit = 1 | server boot time | slot | generation number]

[揮発性ビット= 1 |サーバーの起動時間|スロット|世代番号]

o slot is an index in the server volatile filehandle table

o スロットは、サーバーの揮発性ファイルハンドルテーブルのインデックスです

o generation number is the generation number for the table entry/slot

o 世代番号は、テーブルエントリ/スロットの世代番号です。

When the client presents a volatile filehandle, the server makes the following checks, which assume that the check for the volatile bit has passed. If the server boot time is less than the current server boot time, return NFS4ERR_FHEXPIRED. If slot is out of range, return NFS4ERR_BADHANDLE. If the generation number does not match, return NFS4ERR_FHEXPIRED.


When the server reboots, the table is gone (it is volatile).


If the volatile bit is 0, then it is a persistent filehandle with a different structure following it.


4.3. Client Recovery from Filehandle Expiration
4.3. ファイルハンドルの有効期限からのクライアントの回復

If possible, the client should recover from the receipt of an NFS4ERR_FHEXPIRED error. The client must take on additional responsibility so that it may prepare itself to recover from the expiration of a volatile filehandle. If the server returns persistent filehandles, the client does not need these additional steps.


For volatile filehandles, most commonly the client will need to store the component names leading up to and including the file system object in question. With these names, the client should be able to recover by finding a filehandle in the namespace that is still available or by starting at the root of the server's file system namespace.


If the expired filehandle refers to an object that has been removed from the file system, obviously the client will not be able to recover from the expired filehandle.


It is also possible that the expired filehandle refers to a file that has been renamed. If the file was renamed by another client, again it is possible that the original client will not be able to recover. However, in the case that the client itself is renaming the file and the file is open, it is possible that the client may be able to recover. The client can determine the new pathname based on the processing of the rename request. The client can then regenerate the new filehandle based on the new pathname. The client could also use the COMPOUND operation mechanism to construct a set of operations like:




Note that the COMPOUND procedure does not provide atomicity. This example only reduces the overhead of recovering from an expired filehandle.


5. Attributes
5. の属性

To meet the requirements of extensibility and increased interoperability with non-UNIX platforms, attributes need to be handled in a flexible manner. The NFSv3 fattr3 structure contains a fixed list of attributes that not all clients and servers are able to support or care about. The fattr3 structure cannot be extended as new needs arise, and it provides no way to indicate non-support. With the NFSv4.0 protocol, the client is able to query what attributes the server supports and construct requests with only those supported attributes (or a subset thereof).

UNIX以外のプラットフォームとの拡張性と相互運用性の要件を満たすには、属性を柔軟に処理する必要があります。 NFSv3 fattr3構造には、すべてのクライアントとサーバーがサポートまたは処理できる属性の固定リストが含まれています。新しいニーズが発生した場合、fattr3構造を拡張することはできず、サポートされていないことを示す方法はありません。 NFSv4.0プロトコルを使用すると、クライアントはサーバーがサポートする属性を照会し、サポートされている属性(またはそのサブセット)のみを使用して要求を作成できます。

To this end, attributes are divided into three groups: REQUIRED, RECOMMENDED, and named. Both REQUIRED and RECOMMENDED attributes are supported in the NFSv4.0 protocol by a specific and well-defined encoding and are identified by number. They are requested by setting a bit in the bit vector sent in the GETATTR request; the server response includes a bit vector to list what attributes were returned in the response. New REQUIRED or RECOMMENDED attributes may be added to the NFSv4 protocol as part of a new minor version by publishing a Standards Track RFC that allocates a new attribute number value and defines the encoding for the attribute. See Section 11 for further discussion.

このために、属性はREQUIRED、RECOMMENDED、およびnamedという3つのグループに分けられます。 REQUIRED属性とRECOMMENDED属性の両方が、NFSv4.0プロトコルで特定の明確に定義されたエンコーディングによってサポートされ、番号で識別されます。これらは、GETATTR要求で送信されたビットベクトルにビットを設定することによって要求されます。サーバー応答には、応答で返された属性をリストするビットベクトルが含まれています。新しい属性番号の値を割り当て、属性のエンコーディングを定義するStandards Track RFCを公開することにより、新しいREQUIREDまたはRECOMMENDED属性を新しいマイナーバージョンの一部としてNFSv4プロトコルに追加できます。詳細については、セクション11を参照してください。

Named attributes are accessed by the OPENATTR operation, which accesses a hidden directory of attributes associated with a file system object. OPENATTR takes a filehandle for the object and returns the filehandle for the attribute hierarchy. The filehandle for the named attributes is a directory object accessible by LOOKUP or READDIR and contains files whose names represent the named attributes and whose data bytes are the value of the attribute. For example:

名前付き属性は、ファイルシステムオブジェクトに関連付けられた属性の非表示ディレクトリにアクセスするOPENATTR操作によってアクセスされます。 OPENATTRはオブジェクトのファイルハンドルを受け取り、属性階層のファイルハンドルを返します。名前付き属性のファイルハンドルは、LOOKUPまたはREADDIRによってアクセス可能なディレクトリオブジェクトであり、名前が名前付き属性を表し、データバイトが属性の値であるファイルが含まれています。例えば:

        | LOOKUP   | "foo"     | ; look up file                  |
        | GETATTR  | attrbits  |                                 |
        | OPENATTR |           | ; access foo's named attributes |
        | LOOKUP   | "x11icon" | ; look up specific attribute    |
        | READ     | 0,4096    | ; read stream of bytes          |

Named attributes are intended for data needed by applications rather than by an NFS client implementation. NFS implementers are strongly encouraged to define their new attributes as RECOMMENDED attributes by bringing them to the IETF Standards Track process.

名前付き属性は、NFSクライアント実装ではなく、アプリケーションが必要とするデータを対象としています。 NFS実装者は、IETF標準トラックプロセスにそれらを持ち込むことにより、それらの新しい属性を推奨属性として定義することを強くお勧めします。

The set of attributes that are classified as REQUIRED is deliberately small since servers need to do whatever it takes to support them. A server should support as many of the RECOMMENDED attributes as possible; however, by their definition, the server is not required to support all of them. Attributes are deemed REQUIRED if the data is both needed by a large number of clients and is not otherwise reasonably computable by the client when support is not provided on the server.


Note that the hidden directory returned by OPENATTR is a convenience for protocol processing. The client should not make any assumptions about the server's implementation of named attributes and whether or not the underlying file system at the server has a named attribute directory. Therefore, operations such as SETATTR and GETATTR on the named attribute directory are undefined.


5.1. REQUIRED Attributes
5.1. 必須の属性

These attributes MUST be supported by every NFSv4.0 client and server in order to ensure a minimum level of interoperability. The server MUST store and return these attributes, and the client MUST be able to function with an attribute set limited to these attributes. With just the REQUIRED attributes, some client functionality can be impaired or limited in some ways. A client can ask for any of these attributes to be returned by setting a bit in the GETATTR request. For each such bit set, the server MUST return the corresponding attribute value.

最小レベルの相互運用性を確保するために、これらの属性はすべてのNFSv4.0クライアントとサーバーでサポートされている必要があります。サーバーはこれらの属性を格納して返す必要があり、クライアントはこれらの属性に限定された属性セットで機能できる必要があります。 REQUIRED属性だけでは、一部のクライアント機能が何らかの方法で損なわれたり制限されたりする可能性があります。クライアントは、GETATTR要求にビットを設定することにより、これらの属性のいずれかが返されるように要求できます。そのようなビットセットごとに、サーバーは対応する属性値を返さなければなりません(MUST)。

5.2. RECOMMENDED Attributes
5.2. 推奨属性

These attributes are understood well enough to warrant support in the NFSv4.0 protocol. However, they may not be supported on all clients and servers. A client MAY ask for any of these attributes to be returned by setting a bit in the GETATTR request but MUST handle the case where the server does not return them. A client MAY ask for the set of attributes the server supports and SHOULD NOT request attributes the server does not support. A server should be tolerant of requests for unsupported attributes and simply not return them, rather than considering the request an error. It is expected that servers will support all attributes they comfortably can and only fail to support attributes that are difficult to support in their operating environments. A server should provide attributes whenever they don't have to "tell lies" to the client. For example, a file modification time either should be an accurate time or should not be supported by the server. At times this will be difficult for clients, but a client is better positioned to decide whether and how to fabricate or construct an attribute or whether to do without the attribute.

これらの属性は、NFSv4.0プロトコルでのサポートを保証するのに十分に理解されています。ただし、すべてのクライアントとサーバーでサポートされているとは限りません。クライアントは、GETATTRリクエストにビットを設定することにより、これらの属性のいずれかが返されるように要求できますが、サーバーがそれらを返さない場合を処理しなければなりません(MUST)。クライアントは、サーバーがサポートする属性のセットを要求する場合があり、サーバーがサポートしない属性を要求してはなりません(SHOULD NOT)。サーバーは、要求をエラーと見なすのではなく、サポートされていない属性に対する要求を許容し、それらを単に返さないようにする必要があります。サーバーは快適に使用できるすべての属性をサポートし、オペレーティング環境でサポートするのが難しい属性のみをサポートすることが期待されます。サーバーは、クライアントに「嘘をつく」必要がない場合はいつでも属性を提供する必要があります。たとえば、ファイルの変更時刻は正確な時刻であるか、サーバーでサポートされていない必要があります。これはクライアントにとって困難な場合がありますが、クライアントは、属性を作成または構築するかどうか、どのように作成するか、または属性なしで実行するかどうかを決定するのに適しています。

5.3. Named Attributes
5.3. 名前付き属性

These attributes are not supported by direct encoding in the NFSv4 protocol but are accessed by string names rather than numbers and correspond to an uninterpreted stream of bytes that are stored with the file system object. The namespace for these attributes may be accessed by using the OPENATTR operation. The OPENATTR operation returns a filehandle for a virtual "named attribute directory", and further perusal and modification of the namespace may be done using operations that work on more typical directories. In particular, READDIR may be used to get a list of such named attributes, and LOOKUP and OPEN may select a particular attribute. Creation of a new named attribute may be the result of an OPEN specifying file creation.

これらの属性は、NFSv4プロトコルの直接エンコーディングではサポートされていませんが、数値ではなく文字列名でアクセスされ、ファイルシステムオブジェクトと共に格納される解釈されないバイトストリームに対応しています。これらの属性の名前空間には、OPENATTR操作を使用してアクセスできます。 OPENATTR操作は、仮想の「名前付き属性ディレクトリ」のファイルハンドルを返します。さらに一般的なディレクトリで機能する操作を使用して、名前空間の詳細を調べたり変更したりできます。特に、READDIRはそのような名前付き属性のリストを取得するために使用でき、LOOKUPとOPENは特定の属性を選択できます。新しい名前付き属性の作成は、OPENを指定したファイル作成の結果である可能性があります。

Once an OPEN is done, named attributes may be examined and changed by normal READ and WRITE operations using the filehandles and stateids returned by OPEN.


Named attributes and the named attribute directory may have their own (non-named) attributes. Each of these objects must have all of the REQUIRED attributes and may have additional RECOMMENDED attributes. However, the set of attributes for named attributes and the named attribute directory need not be, and typically will not be, as large as that for other objects in that file system.


Named attributes might be the target of delegations. However, since granting of delegations is at the server's discretion, a server need not support delegations on named attributes.


It is RECOMMENDED that servers support arbitrary named attributes. A client should not depend on the ability to store any named attributes in the server's file system. If a server does support named attributes, a client that is also able to handle them should be able to copy a file's data and metadata with complete transparency from one location to another; this would imply that names allowed for regular directory entries are valid for named attribute names as well.


In NFSv4.0, the structure of named attribute directories is restricted in a number of ways, in order to prevent the development of non-interoperable implementations in which some servers support a fully general hierarchical directory structure for named attributes while others support a limited but adequate structure for named attributes. In such an environment, clients or applications might come to depend on non-portable extensions. The restrictions are:


o CREATE is not allowed in a named attribute directory. Thus, such objects as symbolic links and special files are not allowed to be named attributes. Further, directories may not be created in a named attribute directory, so no hierarchical structure of named attributes for a single object is allowed.

o 名前付き属性ディレクトリではCREATEは許可されていません。したがって、シンボリックリンクや特殊ファイルなどのオブジェクトを名前付き属性にすることはできません。さらに、名前付き属性ディレクトリにディレクトリを作成できないため、単一オブジェクトの名前付き属性の階層構造は許可されません。

o If OPENATTR is done on a named attribute directory or on a named attribute, the server MUST return an error.

o OPENATTRが名前付き属性ディレクトリまたは名前付き属性で行われる場合、サーバーはエラーを返さなければなりません(MUST)。

o Doing a RENAME of a named attribute to a different named attribute directory or to an ordinary (i.e., non-named-attribute) directory is not allowed.

o 名前付き属性のRENAMEを別の名前付き属性ディレクトリまたは通常の(つまり、非名前付き属性)ディレクトリに実行することはできません。

o Creating hard links between named attribute directories or between named attribute directories and ordinary directories is not allowed.

o 名前付き属性ディレクトリ間、または名前付き属性ディレクトリと通常のディレクトリ間にハードリンクを作成することはできません。

Names of attributes will not be controlled by this document or other IETF Standards Track documents. See Section 20 for further discussion.


5.4. Classification of Attributes
5.4. 属性の分類

Each of the attributes accessed using SETATTR and GETATTR (i.e., REQUIRED and RECOMMENDED attributes) can be classified in one of three categories:


1. per-server attributes for which the value of the attribute will be the same for all file objects that share the same server.

1. 同じサーバーを共有するすべてのファイルオブジェクトで属性の値が同じになるサーバーごとの属性。

2. per-file system attributes for which the value of the attribute will be the same for some or all file objects that share the same server and fsid attribute (Section See below for details regarding when such sharing is in effect.

2. 同じサーバーとfsid属性を共有する一部またはすべてのファイルオブジェクトで属性の値が同じになる、ファイルシステムごとの属性(セクション5.8.1.9)。そのような共有がいつ有効になるかについての詳細は、以下を参照してください。

3. per-file system object attributes.

3. ファイルシステムオブジェクトの属性。

The handling of per-file system attributes depends on the particular attribute and the setting of the homogeneous (Section attribute. The following rules apply:


1. The values of the attributes supported_attrs, fsid, homogeneous, link_support, and symlink_support are always common to all objects within the given file system.

1. 属性supported_attrs、fsid、ホモジニアス、link_support、symlink_supportの値は常に、特定のファイルシステム内のすべてのオブジェクトに共通です。

2. For other attributes, different values may be returned for different file system objects if the attribute homogeneous is supported within the file system in question and has the value false.

2. 他の属性の場合、問題のファイルシステム内で同種の属性がサポートされており、値がfalseの場合、ファイルシステムオブジェクトごとに異なる値が返されることがあります。

The classification of attributes is as follows. Note that the attributes time_access_set and time_modify_set are not listed in this section, because they are write-only attributes corresponding to time_access and time_modify and are used in a special instance of SETATTR.


o The per-server attribute is:

o サーバーごとの属性は次のとおりです。



o The per-file system attributes are:

o ファイルごとのシステム属性は次のとおりです。

supported_attrs, fh_expire_type, link_support, symlink_support, unique_handles, aclsupport, cansettime, case_insensitive, case_preserving, chown_restricted, files_avail, files_free, files_total, fs_locations, homogeneous, maxfilesize, maxname, maxread, maxwrite, no_trunc, space_avail, space_free, space_total, and time_delta


o The per-file system object attributes are:

o ファイルシステムオブジェクトごとの属性は次のとおりです。

type, change, size, named_attr, fsid, rdattr_error, filehandle, acl, archive, fileid, hidden, maxlink, mimetype, mode, numlinks, owner, owner_group, rawdev, space_used, system, time_access, time_backup, time_create, time_metadata, time_modify, and mounted_on_fileid


For quota_avail_hard, quota_avail_soft, and quota_used, see their definitions below for the appropriate classification.


5.5. Set-Only and Get-Only Attributes
5.5. Set-OnlyおよびGet-Only属性

Some REQUIRED and RECOMMENDED attributes are set-only; i.e., they can be set via SETATTR but not retrieved via GETATTR. Similarly, some REQUIRED and RECOMMENDED attributes are get-only; i.e., they can be retrieved via GETATTR but not set via SETATTR. If a client attempts to set a get-only attribute or get a set-only attribute, the server MUST return NFS4ERR_INVAL.


5.6. REQUIRED Attributes - List and Definition References
5.6. 必須属性-リストと定義の参照

The list of REQUIRED attributes appears in Table 3. The meanings of the columns of the table are:


o Name: The name of the attribute.

o 名前:属性の名前。

o ID: The number assigned to the attribute. In the event of conflicts between the assigned number and [RFC7531], the latter is authoritative, but in such an event, it should be resolved with errata to this document and/or [RFC7531]. See [IESG_ERRATA] for the errata process.

o ID:属性に割り当てられた番号。割り当てられた番号と[RFC7531]の間に矛盾がある場合、後者は信頼できますが、そのような場合は、このドキュメントまたは[RFC7531]への正誤表で解決する必要があります。エラータプロセスについては、[IESG_ERRATA]を参照してください。

o Data Type: The XDR data type of the attribute.

o データ型:属性のXDRデータ型。

o Acc: Access allowed to the attribute. R means read-only (GETATTR may retrieve, SETATTR may not set). W means write-only (SETATTR may set, GETATTR may not retrieve). R W means read/write (GETATTR may retrieve, SETATTR may set).

o Acc:属性へのアクセスが許可されています。 Rは読み取り専用を意味します(GETATTRは取得、SETATTRは設定されない場合があります)。 Wは書き込み専用を意味します(SETATTRが設定され、GETATTRが取得されない場合があります)。 R Wは読み取り/書き込みを意味します(GETATTRは取得、SETATTRは設定可能)。

o Defined in: The section of this specification that describes the attribute.

o 定義先:属性を説明するこの仕様のセクション。

      | Name            | ID | Data Type  | Acc | Defined in        |
      | supported_attrs | 0  | bitmap4    | R   | Section   |
      | type            | 1  | nfs_ftype4 | R   | Section   |
      | fh_expire_type  | 2  | uint32_t   | R   | Section   |
      | change          | 3  | changeid4  | R   | Section   |
      | size            | 4  | uint64_t   | R W | Section   |
      | link_support    | 5  | bool       | R   | Section   |
      | symlink_support | 6  | bool       | R   | Section   |
      | named_attr      | 7  | bool       | R   | Section   |
      | fsid            | 8  | fsid4      | R   | Section   |
      | unique_handles  | 9  | bool       | R   | Section  |
      | lease_time      | 10 | nfs_lease4 | R   | Section  |
      | rdattr_error    | 11 | nfsstat4   | R   | Section  |
      | filehandle      | 19 | nfs_fh4    | R   | Section  |

Table 3: REQUIRED Attributes


5.7. RECOMMENDED Attributes - List and Definition References
5.7. 推奨属性-リストおよび定義の参照

The RECOMMENDED attributes are defined in Table 4. The meanings of the column headers are the same as Table 3; see Section 5.6 for the meanings.


   | Name              | ID | Data Type       | Acc | Defined in       |
   | acl               | 12 | nfsace4<>       | R W | Section 6.2.1    |
   | aclsupport        | 13 | uint32_t        | R   | Section  |
   | archive           | 14 | bool            | R W | Section  |
   | cansettime        | 15 | bool            | R   | Section  |
   | case_insensitive  | 16 | bool            | R   | Section  |
   | case_preserving   | 17 | bool            | R   | Section  |
   | chown_restricted  | 18 | bool            | R   | Section  |
   | fileid            | 20 | uint64_t        | R   | Section  |
   | files_avail       | 21 | uint64_t        | R   | Section  |
   | files_free        | 22 | uint64_t        | R   | Section  |
   | files_total       | 23 | uint64_t        | R   | Section  |
   | fs_locations      | 24 | fs_locations4   | R   | Section |
   | hidden            | 25 | bool            | R W | Section |
   | homogeneous       | 26 | bool            | R   | Section |
   | maxfilesize       | 27 | uint64_t        | R   | Section |
   | maxlink           | 28 | uint32_t        | R   | Section |
   | maxname           | 29 | uint32_t        | R   | Section |
   | maxread           | 30 | uint64_t        | R   | Section |
   | maxwrite          | 31 | uint64_t        | R   | Section |
   | mimetype          | 32 | ascii_          | R W | Section |
   |                   |    |   REQUIRED4<>   |     |                  |
   | mode              | 33 | mode4           | R W | Section 6.2.2    |
   | mounted_on_fileid | 55 | uint64_t        | R   | Section |
   | no_trunc          | 34 | bool            | R   | Section |
   | numlinks          | 35 | uint32_t        | R   | Section |
   | owner             | 36 | utf8str_mixed   | R W | Section |
   | owner_group       | 37 | utf8str_mixed   | R W | Section |
   | quota_avail_hard  | 38 | uint64_t        | R   | Section |
   | quota_avail_soft  | 39 | uint64_t        | R   | Section |
   | quota_used        | 40 | uint64_t        | R   | Section |
   | rawdev            | 41 | specdata4       | R   | Section |
   | space_avail       | 42 | uint64_t        | R   | Section |
   | space_free        | 43 | uint64_t        | R   | Section |
   | space_total       | 44 | uint64_t        | R   | Section |
   | space_used        | 45 | uint64_t        | R   | Section |
   | system            | 46 | bool            | R W | Section |
   | time_access       | 47 | nfstime4        | R   | Section |
   | time_access_set   | 48 | settime4        | W   | Section |
   | time_backup       | 49 | nfstime4        | R W | Section |
   | time_create       | 50 | nfstime4        | R W | Section |
   | time_delta        | 51 | nfstime4        | R   | Section |
   | time_metadata     | 52 | nfstime4        | R   | Section |
   | time_modify       | 53 | nfstime4        | R   | Section |
   | time_modify_set   | 54 | settime4        | W   | Section |

Table 4: RECOMMENDED Attributes


5.8. Attribute Definitions
5.8. 属性の定義
5.8.1. Definitions of REQUIRED Attributes
5.8.1. 必須属性の定義 Attribute 0: supported_attrs 属性0:supported_attrs

The bit vector that would retrieve all REQUIRED and RECOMMENDED attributes that are supported for this object. The scope of this attribute applies to all objects with a matching fsid.

このオブジェクトでサポートされているすべてのREQUIREDおよびRECOMMENDED属性を取得するビットベクトル。この属性のスコープは、一致するfsidを持つすべてのオブジェクトに適用されます。 Attribute 1: type 属性1:タイプ

Designates the type of an object in terms of one of a number of special constants:


o NF4REG designates a regular file.

o NF4REGは通常のファイルを指定します。

o NF4DIR designates a directory.

o NF4DIRはディレクトリを指定します。

o NF4BLK designates a block device special file.

o NF4BLKは、ブロックデバイス特殊ファイルを指定します。

o NF4CHR designates a character device special file.

o NF4CHRは、キャラクタデバイススペシャルファイルを指定します。

o NF4LNK designates a symbolic link.

o NF4LNKはシンボリックリンクを指定します。

o NF4SOCK designates a named socket special file.

o NF4SOCKは、名前付きソケット特殊ファイルを指定します。

o NF4FIFO designates a fifo special file.

o NF4FIFOは、FIFOスペシャルファイルを指定します。

o NF4ATTRDIR designates a named attribute directory.

o NF4ATTRDIRは、名前付き属性ディレクトリを指定します。

o NF4NAMEDATTR designates a named attribute.

o NF4NAMEDATTRは名前付き属性を指定します。

Within the explanatory text and operation descriptions, the following phrases will be used with the meanings given below:


o The phrase "is a directory" means that the object's type attribute is NF4DIR or NF4ATTRDIR.

o 「is a directory」という語句は、オブジェクトのtype属性がNF4DIRまたはNF4ATTRDIRであることを意味します。

o The phrase "is a special file" means that the object's type attribute is NF4BLK, NF4CHR, NF4SOCK, or NF4FIFO.

o 「特殊ファイルです」という語句は、オブジェクトのタイプ属性がNF4BLK、NF4CHR、NF4SOCK、またはNF4FIFOであることを意味します。

o The phrase "is a regular file" means that the object's type attribute is NF4REG or NF4NAMEDATTR.

o 「通常のファイルです」という語句は、オブジェクトのタイプ属性がNF4REGまたはNF4NAMEDATTRであることを意味します。

o The phrase "is a symbolic link" means that the object's type attribute is NF4LNK.

o 「シンボリックリンクです」という語句は、オブジェクトのタイプ属性がNF4LNKであることを意味します。 Attribute 2: fh_expire_type 属性2:fh_expire_type

The server uses this to specify filehandle expiration behavior to the client. See Section 4 for additional description.

サーバーはこれを使用して、ファイルハンドルの有効期限の動作をクライアントに指定します。詳細については、セクション4を参照してください。 Attribute 3: change 属性3:変更

A value created by the server that the client can use to determine if file data, directory contents, or attributes of the object have been modified. The server MAY return the object's time_metadata attribute for this attribute's value but only if the file system object cannot be updated more frequently than the resolution of time_metadata.

サーバーが作成した値で、クライアントがオブジェクトのファイルデータ、ディレクトリの内容、または属性が変更されているかどうかを判断するために使用できます。サーバーは、この属性の値に対してオブジェクトのtime_metadata属性を返す場合がありますが、それは、ファイルシステムオブジェクトがtime_metadataの解像度よりも頻繁に更新できない場合に限られます。 Attribute 4: size 属性4:サイズ

The size of the object in bytes.

オブジェクトのサイズ(バイト単位)。 Attribute 5: link_support 属性5:link_support

TRUE, if the object's file system supports hard links.

オブジェクトのファイルシステムがハードリンクをサポートしている場合はTRUE。 Attribute 6: symlink_support 属性6:symlink_support

TRUE, if the object's file system supports symbolic links.

オブジェクトのファイルシステムがシンボリックリンクをサポートしている場合はTRUE。 Attribute 7: named_attr 属性7:named_attr

TRUE, if this object has named attributes. In other words, this object has a non-empty named attribute directory.

このオブジェクトに名前付き属性がある場合はTRUE。つまり、このオブジェクトには空でない名前付き属性ディレクトリがあります。 Attribute 8: fsid 属性8:fsid

Unique file system identifier for the file system holding this object. The fsid attribute has major and minor components, each of which are of data type uint64_t.

このオブジェクトを保持するファイルシステムの一意のファイルシステム識別子。 fsid属性には、メジャーコンポーネントとマイナーコンポーネントがあり、それぞれデータタイプuint64_tです。 Attribute 9: unique_handles 属性9:unique_handles

TRUE, if two distinct filehandles are guaranteed to refer to two different file system objects.

2つの異なるファイルハンドルが2つの異なるファイルシステムオブジェクトを参照することが保証されている場合はTRUE。 Attribute 10: lease_time 属性10:lease_time

Duration of the lease at the server in seconds.

サーバーでのリース期間(秒単位)。 Attribute 11: rdattr_error 属性11:rdattr_error

Error returned from an attempt to retrieve attributes during a READDIR operation.

READDIR操作中に属性を取得しようとしたときに返されたエラー。 Attribute 19: filehandle 属性19:ファイルハンドル

The filehandle of this object (primarily for READDIR requests).


5.8.2. Definitions of Uncategorized RECOMMENDED Attributes
5.8.2. 未分類の推奨属性の定義

The definitions of most of the RECOMMENDED attributes follow. Collections that share a common category are defined in other sections.

ほとんどのRECOMMENDED属性の定義は次のとおりです。共通のカテゴリを共有するコレクションは、他のセクションで定義されています。 Attribute 14: archive 属性14:アーカイブ

TRUE, if this file has been archived since the time of the last modification (deprecated in favor of time_backup).

TRUE、このファイルが最後に変更された時刻以降にアーカイブされている場合(time_backupの代わりに非推奨)。 Attribute 15: cansettime 属性15:cansettime

TRUE, if the server is able to change the times for a file system object as specified in a SETATTR operation.

サーバーがSETATTR操作で指定されたファイルシステムオブジェクトの時間を変更できる場合はTRUE。 Attribute 16: case_insensitive 属性16:case_insensitive

TRUE, if filename comparisons on this file system are case insensitive. This refers only to comparisons, and not to the case in which filenames are stored.

このファイルシステムでのファイル名の比較で大文字と小文字が区別されない場合はTRUE。これは比較のみを指し、ファイル名が格納されている場合は指しません。 Attribute 17: case_preserving 属性17:case_preserving

TRUE, if the filename case on this file system is preserved. This refers only to how filenames are stored, and not to how they are compared. Filenames stored in mixed case might be compared using either case-insensitive or case-sensitive comparisons.

このファイルシステムのファイル名の大文字と小文字が保持される場合はTRUE。これは、ファイル名の保存方法のみを指し、比較方法は指しません。大/小文字混合で保管されたファイル名は、大/小文字を区別しない比較または大/小文字を区別する比較のいずれかを使用して比較される場合があります。 Attribute 18: chown_restricted 属性18:chown_restricted

If TRUE, the server will reject any request to change either the owner or the group associated with a file if the caller is not a privileged user (for example, "root" in UNIX operating environments or the "Take Ownership" privilege in Windows 2000).

TRUEの場合、呼び出し元が特権ユーザー(たとえば、UNIXオペレーティング環境の「root」またはWindows 2000の「Take Ownership」特権)でない場合、サーバーは、ファイルに関連付けられた所有者またはグループのいずれかを変更する要求を拒否します。 )。 Attribute 20: fileid 属性20:fileid

A number uniquely identifying the file within the file system.

ファイルシステム内でファイルを一意に識別する番号。 Attribute 21: files_avail 属性21:files_avail

File slots available to this user on the file system containing this object -- this should be the smallest relevant limit.

このオブジェクトを含むファイルシステムでこのユーザーが使用できるファイルスロット-これは、関連する最小の制限です。 Attribute 22: files_free 属性22:files_free

Free file slots on the file system containing this object -- this should be the smallest relevant limit.

このオブジェクトを含むファイルシステムの空きファイルスロット-これは、関連する最小の制限です。 Attribute 23: files_total 属性23:files_total

Total file slots on the file system containing this object.

このオブジェクトを含むファイルシステム上の合計ファイルスロット。 Attribute 24: fs_locations 属性24:fs_locations

Locations where this file system may be found. If the server returns NFS4ERR_MOVED as an error, this attribute MUST be supported.


The server specifies the rootpath for a given server by returning a path consisting of zero path components.

サーバーは、ゼロパスコンポーネントで構成されるパスを返すことにより、特定のサーバーのルートパスを指定します。 Attribute 25: hidden 属性25:非表示

TRUE, if the file is considered hidden with respect to the Windows API.

Windows APIに関してファイルが非表示と見なされる場合はTRUE。 Attribute 26: homogeneous 属性26:同種

TRUE, if this object's file system is homogeneous, i.e., all objects in the file system (all objects on the server with the same fsid) have common values for all per-file system attributes.

このオブジェクトのファイルシステムが同種の場合、つまりファイルシステム内のすべてのオブジェクト(同じfsidを持つサーバー上のすべてのオブジェクト)が、ファイルシステムごとのすべての属性に共通の値を持つ場合はTRUE。 Attribute 27: maxfilesize 属性27:maxfilesize

Maximum supported file size for the file system of this object.

このオブジェクトのファイルシステムでサポートされる最大ファイルサイズ。 Attribute 28: maxlink 属性28:maxlink

Maximum number of hard links for this object.

このオブジェクトのハードリンクの最大数。 Attribute 29: maxname 属性29:maxname

Maximum filename size supported for this object.

このオブジェクトでサポートされるファイル名の最大サイズ。 Attribute 30: maxread 属性30:maxread

Maximum amount of data the READ operation will return for this object.

このオブジェクトに対してREAD操作が返すデータの最大量。 Attribute 31: maxwrite 属性31:maxwrite

Maximum amount of data the WRITE operation will accept for this object. This attribute SHOULD be supported if the file is writable. Lack of this attribute can lead to the client either wasting bandwidth or not receiving the best performance.

このオブジェクトに対してWRITE操作が受け入れるデータの最大量。ファイルが書き込み可能である場合、この属性はサポートされるべきです(SHOULD)。この属性がないと、クライアントが帯域幅を浪費したり、最高のパフォーマンスを受け取っていない可能性があります。 Attribute 32: mimetype 属性32:mimetype

MIME media type/subtype of this object.

このオブジェクトのMIMEメディアタイプ/サブタイプ。 Attribute 55: mounted_on_fileid 属性55:Mounted_on_fileid

Like fileid, but if the target filehandle is the root of a file system, this attribute represents the fileid of the underlying directory.


UNIX-based operating environments connect a file system into the namespace by connecting (mounting) the file system onto the existing file object (the mount point, usually a directory) of an existing file system. When the mount point's parent directory is read via an API such as readdir() [readdir_api], the return results are directory entries, each with a component name and a fileid. The fileid of the mount point's directory entry will be different from the fileid that the stat() [stat] system call returns. The stat() system call is returning the fileid of the root of the mounted file system, whereas readdir() is returning the fileid that stat() would have returned before any file systems were mounted on the mount point.

UNIXベースのオペレーティング環境では、ファイルシステムを既存のファイルシステムの既存のファイルオブジェクト(マウントポイント、通常はディレクトリ)に接続(マウント)することにより、ファイルシステムをネームスペースに接続します。マウントポイントの親ディレクトリがreaddir()[readdir_api]などのAPIを介して読み取られる場合、返される結果はディレクトリエントリで、それぞれにコンポーネント名とファイルIDが含まれます。マウントポイントのディレクトリエントリのファイルIDは、stat()[stat]システムコールが返すファイルIDとは異なります。 stat()システムコールはマウントされたファイルシステムのルートのファイルIDを返しますが、readdir()は、ファイルシステムがマウントポイントにマウントされる前にstat()が返したはずのファイルIDを返します。

Unlike NFSv3, NFSv4.0 allows a client's LOOKUP request to cross other file systems. The client detects the file system crossing whenever the filehandle argument of LOOKUP has an fsid attribute different from that of the filehandle returned by LOOKUP. A UNIX-based client will consider this a "mount point crossing". UNIX has a legacy scheme for allowing a process to determine its current working directory. This relies on readdir() of a mount point's parent and stat() of the mount point returning fileids as previously described. The mounted_on_fileid attribute corresponds to the fileid that readdir() would have returned, as described previously.

NFSv3とは異なり、NFSv4.0では、クライアントのLOOKUP要求が他のファイルシステムを越えることができます。クライアントは、LOOKUPのfilehandle引数に、LOOKUPから返されたファイルハンドルのfsid属性とは異なるfsid属性がある場合に、ファイルシステムの交差を検出します。 UNIXベースのクライアントは、これを「マウントポイントクロッシング」と見なします。 UNIXには、プロセスが現在の作業ディレクトリを決定できるようにするためのレガシースキームがあります。これは、前述のように、マウントポイントの親のreaddir()とマウントポイントのstat()がファイルIDを返すことに依存しています。前述のように、mounted_on_fileid属性は、readdir()が返すファイルIDに対応します。

While the NFSv4.0 client could simply fabricate a fileid corresponding to what mounted_on_fileid provides (and if the server does not support mounted_on_fileid, the client has no choice), there is a risk that the client will generate a fileid that conflicts with one that is already assigned to another object in the file system. Instead, if the server can provide the mounted_on_fileid, the potential for client operational problems in this area is eliminated.


If the server detects that there is nothing mounted on top of the target file object, then the value for mounted_on_fileid that it returns is the same as that of the fileid attribute.


The mounted_on_fileid attribute is RECOMMENDED, so the server SHOULD provide it if possible, and for a UNIX-based server, this is straightforward. Usually, mounted_on_fileid will be requested during a READDIR operation, in which case it is trivial (at least for UNIX-based servers) to return mounted_on_fileid since it is equal to the fileid of a directory entry returned by readdir(). If mounted_on_fileid is requested in a GETATTR operation, the server should obey an invariant that has it returning a value that is equal to the file object's entry in the object's parent directory, i.e., what readdir() would have returned. Some operating environments allow a series of two or more file systems to be mounted onto a single mount point. In this case, for the server to obey the aforementioned invariant, it will need to find the base mount point, and not the intermediate mount points.

Mounted_on_fileid属性は推奨されるので、サーバーは可能であればそれを提供する必要があります(SHOULD)。UNIXベースのサーバーの場合、これは簡単です。通常、mounted_on_fileidはREADDIR操作中に要求されます。その場合、readdir()によって返されるディレクトリエントリのfileidと等しいため、mounted_on_fileidを返すのは(少なくともUNIXベースのサーバーの場合)簡単です。 GETATTR操作でMounted_on_fileidが要求された場合、サーバーは、オブジェクトの親ディレクトリにあるファイルオブジェクトのエントリと等しい値を返す不変条件に従う必要があります。つまり、readdir()が返す結果になります。一部の動作環境では、一連の2つ以上のファイルシステムを単一のマウントポイントにマウントできます。この場合、サーバーが前述の不変式に従うためには、中間マウントポイントではなく、ベースマウントポイントを見つける必要があります。 Attribute 34: no_trunc 属性34:no_trunc

If this attribute is TRUE, then if the client uses a filename longer than name_max, an error will be returned instead of the name being truncated.

この属性がTRUEの場合、クライアントがname_maxより長いファイル名を使用すると、名前が切り捨てられる代わりにエラーが返されます。 Attribute 35: numlinks 属性35:numlinks

Number of hard links to this object.

このオブジェクトへのハードリンクの数。 Attribute 36: owner 属性36:所有者

The string name of the owner of this object.

このオブジェクトの所有者の文字列名。 Attribute 37: owner_group 属性37:owner_group

The string name of the group ownership of this object.

このオブジェクトのグループ所有権の文字列名。 Attribute 38: quota_avail_hard 属性38:quota_avail_hard

The value in bytes that represents the amount of additional disk space beyond the current allocation that can be allocated to this file or directory before further allocations will be refused. It is understood that this space may be consumed by allocations to other files or directories.

これ以上の割り当てが拒否される前に、このファイルまたはディレクトリに割り当てることができる現在の割り当てを超える追加のディスク領域の量を表すバイト単位の値。このスペースは、他のファイルまたはディレクトリへの割り当てによって消費される可能性があることを理解してください。 Attribute 39: quota_avail_soft 属性39:quota_avail_soft

The value in bytes that represents the amount of additional disk space that can be allocated to this file or directory before the user may reasonably be warned. It is understood that this space may be consumed by allocations to other files or directories, though there may exist server-side rules as to which other files or directories.

ユーザーに警告が出る前にこのファイルまたはディレクトリに割り当てることができる追加のディスク容量を表すバイト単位の値。このスペースは他のファイルまたはディレクトリへの割り当てによって消費される可能性がありますが、他のどのファイルまたはディレクトリに関するサーバー側のルールが存在する場合もあります。 Attribute 40: quota_used 属性40:quota_used

The value in bytes that represents the amount of disk space used by this file or directory and possibly a number of other similar files or directories, where the set of "similar" meets at least the criterion that allocating space to any file or directory in the set will reduce the "quota_avail_hard" of every other file or directory in the set.


Note that there may be a number of distinct but overlapping sets of files or directories for which a quota_used value is maintained, e.g., "all files with a given owner", "all files with a given group owner", etc. The server is at liberty to choose any of those sets when providing the content of the quota_used attribute but should do so in a repeatable way. The rule may be configured per file system or may be "choose the set with the smallest quota".

quota_used値が維持されるファイルまたはディレクトリのセットは、重複している場合があります。たとえば、「特定の所有者を持つすべてのファイル」、「特定のグループ所有者を持つすべてのファイル」などです。サーバーはquota_used属性のコンテンツを提供するときにこれらのセットのいずれかを自由に選択できますが、繰り返し可能な方法で行う必要があります。ルールはファイルシステムごとに構成することも、「クォータが最小のセットを選択する」こともできます。 Attribute 41: rawdev 属性41:rawdev

Raw device number of file of type NF4BLK or NF4CHR. The device number is split into major and minor numbers. If the file's type attribute is not NF4BLK or NF4CHR, this attribute SHOULD NOT be returned, and any value returned SHOULD NOT be considered useful.

タイプNF4BLKまたはNF4CHRのファイルのrawデバイス番号。デバイス番号は、メジャー番号とマイナー番号に分かれています。ファイルのtype属性がNF4BLKまたはNF4CHRでない場合、この属性は返されるべきではなく(SHOULD NOT)、返された値は有用であるとは見なされません(SHOULD NOT)。 Attribute 42: space_avail 属性42:space_avail

Disk space in bytes available to this user on the file system containing this object -- this should be the smallest relevant limit.

このオブジェクトを含むファイルシステム上でこのユーザーが使用できるディスク容量(バイト単位)-これは、関連する最小の制限です。 Attribute 43: space_free 属性43:space_free

Free disk space in bytes on the file system containing this object -- this should be the smallest relevant limit.

このオブジェクトを含むファイルシステムの空きディスク容量(バイト単位)-これは、関連する最小の制限です。 Attribute 44: space_total 属性44:space_total

Total disk space in bytes on the file system containing this object.

このオブジェクトを含むファイルシステムの合計ディスク容量(バイト単位)。 Attribute 45: space_used 属性45:space_used

Number of file system bytes allocated to this object.

このオブジェクトに割り当てられているファイルシステムのバイト数。 Attribute 46: system 属性46:システム

TRUE, if this file is a "system" file with respect to the Windows operating environment.

このファイルがWindowsオペレーティング環境に関する「システム」ファイルである場合はTRUE。 Attribute 47: time_access 属性47:time_access

Represents the time of last access to the object by a READ operation sent to the server. The notion of what is an "access" depends on the server's operating environment and/or the server's file system semantics. For example, for servers obeying Portable Operating System Interface (POSIX) semantics, time_access would be updated only by the READ and READDIR operations and not any of the operations that modify the content of the object [read_api], [readdir_api], [write_api]. Of course, setting the corresponding time_access_set attribute is another way to modify the time_access attribute.

サーバーに送信されたREAD操作によってオブジェクトに最後にアクセスした時刻を表します。 「アクセス」とは何かの概念は、サーバーの動作環境やサーバーのファイルシステムのセマンティクスによって異なります。たとえば、ポータブルオペレーティングシステムインターフェイス(POSIX)のセマンティクスに従うサーバーの場合、time_accessはREADおよびREADDIR操作によってのみ更新され、オブジェクトの内容を変更する操作[read_api]、[readdir_api]、[write_api]では更新されません。もちろん、対応するtime_access_set属性を設定することは、time_access属性を変更するもう1つの方法です。

Whenever the file object resides on a writable file system, the server should make its best efforts to record time_access into stable storage. However, to mitigate the performance effects of doing so, and most especially whenever the server is satisfying the read of the object's content from its cache, the server MAY cache access time updates and lazily write them to stable storage. It is also acceptable to give administrators of the server the option to disable time_access updates.

ファイルオブジェクトが書き込み可能なファイルシステムに存在する場合は常に、サーバーはtime_accessを安定したストレージに記録するために最善の努力をする必要があります。ただし、そうすることによるパフォーマンスへの影響を軽減するために、特にサーバーがキャッシュからのオブジェクトのコンテンツの読み取りを満たしている場合は常に、サーバーはアクセス時間の更新をキャッシュして、それらを安定したストレージに遅延書き込みする場合があります。サーバーの管理者に、time_access更新を無効にするオプションを与えることもできます。 Attribute 48: time_access_set 属性48:time_access_set

Sets the time of last access to the object. SETATTR use only.

オブジェクトに最後にアクセスした時刻を設定します。 SETATTRの使用のみ。 Attribute 49: time_backup 属性49:time_backup

The time of last backup of the object.

オブジェクトの最後のバックアップの時刻。 Attribute 50: time_create 属性50:time_create

The time of creation of the object. This attribute does not have any relation to the traditional UNIX file attribute "ctime" ("change time").

オブジェクトの作成時刻。この属性は、従来のUNIXファイル属性 "ctime"( "変更時刻")とは関係ありません。 Attribute 51: time_delta 属性51:time_delta

Smallest useful server time granularity.

最小の有用なサーバー時間の細分性。 Attribute 52: time_metadata 属性52:time_metadata

The time of last metadata modification of the object.

オブジェクトのメタデータが最後に変更された時刻。 Attribute 53: time_modify 属性53:time_modify

The time of last modification to the object.

オブジェクトが最後に変更された時刻。 Attribute 54: time_modify_set 属性54:time_modify_set

Sets the time of last modification to the object. SETATTR use only.

オブジェクトの最終変更時刻を設定します。 SETATTRの使用のみ。

5.9. Interpreting owner and owner_group
5.9. ownerおよびowner_groupの解釈

The RECOMMENDED attributes "owner" and "owner_group" (and also users and groups used as values of the who field within nfs4ace structures used in the acl attribute) are represented in the form of UTF-8 strings. This format avoids the use of a representation that is tied to a particular underlying implementation at the client or server. Note that Section 6.1 of [RFC2624] provides additional rationale. It is expected that the client and server will have their own local representation of owners and groups that is used for local storage or presentation to the application via APIs that expect such a representation. Therefore, the protocol requires that when these attributes are transferred between the client and server, the local representation is translated to a string of the form "identifier@dns_domain". This allows clients and servers that do not use the same local representation to effectively interoperate since they both use a common syntax that can be interpreted by both.

推奨属性「owner」と「owner_group」(およびacl属性で使用されるnfs4ace構造内のwhoフィールドの値として使用されるユーザーとグループ)は、UTF-8文字列の形式で表されます。この形式では、クライアントまたはサーバーで特定の基本的な実装に関連付けられている表現の使用が回避されます。 [RFC2624]のセクション6.1が追加の根拠を提供していることに注意してください。クライアントとサーバーは、所有者とグループの独自のローカル表現を持ち、ローカルストレージまたはそのような表現を期待するAPIを介したアプリケーションへのプレゼンテーションに使用されることが期待されます。したがって、プロトコルでは、これらの属性がクライアントとサーバー間で転送されるときに、ローカル表現が「identifier @ dns_domain」の形式の文字列に変換される必要があります。これにより、同じローカル表現を使用しないクライアントとサーバーは、両方で解釈できる共通の構文を使用するため、効率的に相互運用できます。

Similarly, security principals may be represented in different ways by different security mechanisms. Servers normally translate these representations into a common format, generally that used by local storage, to serve as a means of identifying the users corresponding to these security principals. When these local identifiers are translated to the form of the owner attribute, associated with files created by such principals, they identify, in a common format, the users associated with each corresponding set of security principals.


The translation used to interpret owner and group strings is not specified as part of the protocol. This allows various solutions to be employed. For example, a local translation table may be consulted that maps a numeric identifier to the user@dns_domain syntax. A name service may also be used to accomplish the translation. A server may provide a more general service, not limited by any particular translation (which would only translate a limited set of possible strings) by storing the owner and owner_group attributes in local storage without any translation, or it may augment a translation method by storing the entire string for attributes for which no translation is available while using the local representation for those cases in which a translation is available.

所有者とグループの文字列を解釈するために使用される変換は、プロトコルの一部として指定されていません。これにより、さまざまなソリューションを使用できます。たとえば、数値識別子をuser @ dns_domain構文にマップするローカル変換テーブルが参照される場合があります。ネームサービスを使用して、変換を行うこともできます。サーバーは、owner属性とowner_group属性を翻訳なしでローカルストレージに保存することにより、特定の翻訳に限定されない(可能な文字列の限られたセットのみを翻訳する)より一般的なサービスを提供するか、または保存することで翻訳方法を強化できます。翻訳が利用可能な場合にローカル表現を使用しているときに、翻訳が利用できない属性の文字列全体。

Servers that do not provide support for all possible values of user and group strings SHOULD return an error (NFS4ERR_BADOWNER) when a string is presented that has no translation, as the value to be set for a SETATTR of the owner or owner_group attributes or as part of the value of the acl attribute. When a server does accept a user or group string as valid on a SETATTR, it is promising to return that same string (see below) when a corresponding GETATTR is done, as long as there has been no further change in the corresponding attribute before the GETATTR. For some internationalization-related exceptions where this is not possible, see below. Configuration changes (including changes from the mapping of the string to the local representation) and ill-constructed name translations (those that contain aliasing) may make that promise impossible to honor. Servers should make appropriate efforts to avoid a situation in which these attributes have their values changed when no real change to either ownership or acls has occurred.

ユーザーおよびグループ文字列のすべての可能な値のサポートを提供しないサーバーは、所有者またはowner_group属性のSETATTRに設定される値として、または一部として、翻訳されていない文字列が提示されるとエラー(NFS4ERR_BADOWNER)を返す必要があります(SHOULD) acl属性の値の。サーバーがユーザーまたはグループの文字列をSETATTRで有効なものとして受け入れる場合、対応する属性に変更が加えられていない限り、対応するGETATTRが実行されたときに同じ文字列(以下を参照)を返すことが約束されています。 GETATTR。これが不可能な一部の国際化関連の例外については、以下を参照してください。構成の変更(文字列のローカル表現へのマッピングからの変更を含む)および不適切に構築された名前の変換(エイリアスを含むもの)により、その約束を守ることができなくなる場合があります。サーバーは、所有権またはACLのいずれかに実際の変更が発生していないときにこれらの属性の値が変更される状況を回避するために、適切な努力をする必要があります。

The "dns_domain" portion of the owner string is meant to be a DNS domain name -- for example, "". Servers should accept as valid a set of users for at least one domain. A server may treat other domains as having no valid translations. A more general service is provided when a server is capable of accepting users for multiple domains, or for all domains, subject to security constraints.


As an implementation guide, both clients and servers may provide a means to configure the "dns_domain" portion of the owner string. For example, the DNS domain name of the host running the NFS server might be "", but the user names are defined in "". In the absence of such a configuration, or as a default, the current DNS domain name of the server should be the value used for the "dns_domain".


As mentioned above, it is desirable that a server, when accepting a string of the form "user@domain" or "group@domain" in an attribute, return this same string when that corresponding attribute is fetched. Internationalization issues make this impossible under certain circumstances, and the client needs to take note of these. See Section 12 for a detailed discussion of these issues.

上記のように、サーバーが属性で「user @ domain」または「group @ domain」の形式の文字列を受け入れる場合、対応する属性がフェッチされたときにこの同じ文字列を返すことが望ましいです。国際化の問題は特定の状況下ではこれを不可能にし、クライアントはこれらに注意する必要があります。これらの問題の詳細については、セクション12を参照してください。

In the case where there is no translation available to the client or server, the attribute value will be constructed without the "@". Therefore, the absence of the "@" from the owner or owner_group attribute signifies that no translation was available at the sender and that the receiver of the attribute should not use that string as a basis for translation into its own internal format. Even though the attribute value cannot be translated, it may still be useful. In the case of a client, the attribute string may be used for local display of ownership.


To provide a greater degree of compatibility with NFSv3, which identified users and groups by 32-bit unsigned user identifiers and group identifiers, owner and group strings that consist of ASCII-encoded decimal numeric values with no leading zeros can be given a special interpretation by clients and servers that choose to provide such support. The receiver may treat such a user or group string as representing the same user as would be represented by an NFSv3 uid or gid having the corresponding numeric value.

32ビットの署名されていないユーザー識別子とグループ識別子によってユーザーとグループを識別したNFSv3との互換性を高めるために、先行ゼロのないASCIIエンコードされた10進数の数値で構成される所有者とグループの文字列は、そのようなサポートを提供することを選択したクライアントとサーバー。受信者は、そのようなユーザーまたはグループ文字列を、対応する数値を持つNFSv3 uidまたはgidによって表されるのと同じユーザーを表すものとして扱うことができます。

A server SHOULD reject such a numeric value if the security mechanism is using Kerberos. That is, in such a scenario, the client will already need to form "user@domain" strings. For any other security mechanism, the server SHOULD accept such numeric values. As an implementation note, the server could make such an acceptance be configurable. If the server does not support numeric values or if it is configured off, then it MUST return an NFS4ERR_BADOWNER error. If the security mechanism is using Kerberos and the client attempts to use the special form, then the server SHOULD return an NFS4ERR_BADOWNER error when there is a valid translation for the user or owner designated in this way. In that case, the client must use the appropriate user@domain string and not the special form for compatibility.

セキュリティメカニズムがKerberosを使用している場合、サーバーはこのような数値を拒否する必要があります(SHOULD)。つまり、このようなシナリオでは、クライアントはすでに「user @ domain」文字列を形成する必要があります。他のセキュリティメカニズムでは、サーバーはそのような数値を受け入れる必要があります(SHOULD)。実装上の注意として、サーバーはそのような受け入れを構成可能にすることができます。サーバーが数値をサポートしていない場合、またはサーバーがオフに構成されている場合は、NFS4ERR_BADOWNERエラーを返す必要があります。セキュリティメカニズムがKerberosを使用していて、クライアントが特別な形式を使用しようとした場合、この方法で指定されたユーザーまたは所有者の有効な変換があると、サーバーはNFS4ERR_BADOWNERエラーを返す必要があります。その場合、クライアントは、互換性のための特別な形式ではなく、適切なuser @ domain文字列を使用する必要があります。

The client MUST always accept numeric values if the security mechanism is not RPCSEC_GSS. A client can determine if a server supports numeric identifiers by first attempting to provide a numeric identifier. If this attempt is rejected with an NFS4ERR_BADOWNER error, then the client should only use named identifiers of the form "user@dns_domain".

セキュリティメカニズムがRPCSEC_GSSでない場合、クライアントは常に数値を受け入れる必要があります。クライアントは、最初に数値識別子を提供しようとすることにより、サーバーが数値識別子をサポートしているかどうかを判断できます。この試みがNFS4ERR_BADOWNERエラーで拒否された場合、クライアントは「user @ dns_domain」形式の名前付き識別子のみを使用する必要があります。

The owner string "nobody" may be used to designate an anonymous user, which will be associated with a file created by a security principal that cannot be mapped through normal means to the owner attribute.


5.10. Character Case Attributes
5.10. 文字ケース属性

With respect to the case_insensitive and case_preserving attributes, case-insensitive comparisons of Unicode characters SHOULD use Unicode Default Case Folding as defined in Chapter 3 of the Unicode Standard [UNICODE] and MAY override that behavior for specific selected characters with the case folding defined in the SpecialCasing.txt [SPECIALCASING] file; see Section 3.13 of the Unicode Standard.

case_insensitive属性とcase_preserving属性に関して、Unicode文字の比較では大文字と小文字を区別せず、Unicode Standard [UNICODE]の第3章で定義されているUnicodeデフォルトのCase Foldingを使用して(SHOULD)、特定の選択された文字の動作を、 SpecialCasing.txt [SPECIALCASING]ファイル。 Unicode標準のセクション3.13を参照してください。

The SpecialCasing.txt file replaces the Default Case Folding with locale- and context-dependent case folding for specific situations. An example of locale- and context-dependent case folding is that LATIN CAPITAL LETTER I ("I", U+0049) is default case folded to LATIN SMALL LETTER I ("i", U+0069). However, several languages (e.g., Turkish) treat an "I" character with a dot as a different letter than an "I" character without a dot; therefore, in such languages, unless an I is before a dot_above, the "I" (U+0049) character should be case folded to a different character, LATIN SMALL LETTER DOTLESS I (U+0131).

SpecialCasing.txtファイルは、デフォルトのケースフォールディングを、特定の状況でロケールおよびコンテキストに依存するケースフォールディングに置き換えます。ロケールとコンテキストに依存する大文字小文字の折りたたみの例は、ラテン大文字I( "I"、U + 0049)がデフォルトの小文字小文字I( "i"、U + 0069)に折りたたまれていることです。ただし、いくつかの言語(トルコ語など)では、ドットのある「I」文字を、ドットのない「I」文字とは異なる文字として扱います。したがって、そのような言語では、Iがdot_aboveの前にない限り、「I」(U + 0049)文字は大文字小文字の異なる文字、ラテン文字小文字ドットI(U + 0131)に変換する必要があります。

The [UNICODE] and [SPECIALCASING] references in this RFC are for version 7.0.0 of the Unicode standard, as that was the latest version of Unicode when this RFC was published. Implementations SHOULD always use the latest version of Unicode (<>).


6. Access Control Attributes
6. アクセス制御属性

Access Control Lists (ACLs) are file attributes that specify fine-grained access control. This section covers the "acl", "aclsupport", and "mode" file attributes, and their interactions. Note that file attributes may apply to any file system object.


6.1. Goals
6.1. ゴール

ACLs and modes represent two well-established models for specifying permissions. This section specifies requirements that attempt to meet the following goals:


o If a server supports the mode attribute, it should provide reasonable semantics to clients that only set and retrieve the mode attribute.

o サーバーがモード属性をサポートしている場合、モード属性の設定と取得のみを行うクライアントに適切なセマンティクスを提供する必要があります。

o If a server supports ACL attributes, it should provide reasonable semantics to clients that only set and retrieve those attributes.

o サーバーがACL属性をサポートする場合、それらの属性の設定と取得のみを行うクライアントに適切なセマンティクスを提供する必要があります。

o On servers that support the mode attribute, if ACL attributes have never been set on an object, via inheritance or explicitly, the behavior should be traditional UNIX-like behavior.

o mode属性をサポートするサーバーでは、継承または明示的にオブジェクトにACL属性が設定されていない場合、動作は従来のUNIXに似た動作である必要があります。

o On servers that support the mode attribute, if the ACL attributes have been previously set on an object, either explicitly or via inheritance:

o モード属性をサポートするサーバーで、ACL属性がオブジェクトに以前に明示的または継承によって設定されている場合:

* Setting only the mode attribute should effectively control the traditional UNIX-like permissions of read, write, and execute on owner, owner_group, and other.

* mode属性のみを設定することで、owner、owner_groupなどに対する、従来のUNIXに似た読み取り、書き込み、実行のアクセス許可を効果的に制御できます。

* Setting only the mode attribute should provide reasonable security. For example, setting a mode of 000 should be enough to ensure that future opens for read or write by any principal fail, regardless of a previously existing or inherited ACL.

* mode属性のみを設定すると、妥当なセキュリティが提供されます。たとえば、000のモードを設定すれば、既存のACLや継承されたACLに関係なく、プリンシパルによる読み取りまたは書き込みの将来のオープンが失敗することを保証するには十分です。

o When a mode attribute is set on an object, the ACL attributes may need to be modified so as to not conflict with the new mode. In such cases, it is desirable that the ACL keep as much information as possible. This includes information about inheritance, AUDIT and ALARM access control entries (ACEs), and permissions granted and denied that do not conflict with the new mode.

o オブジェクトにモード属性が設定されている場合、新しいモードと競合しないようにACL属性を変更する必要がある場合があります。そのような場合、ACLができるだけ多くの情報を保持することが望ましいです。これには、継承、AUDITおよびALARMアクセスコントロールエントリ(ACE)、および新しいモードと競合しない許可および拒否されたアクセス許可に関する情報が含まれます。

6.2. File Attributes Discussion
6.2. ファイル属性のディスカッション

Support for each of the ACL attributes is RECOMMENDED and not required, since file systems accessed using NFSv4 might not support ACLs.


6.2.1. Attribute 12: acl
6.2.1. 属性12:acl

The NFSv4.0 ACL attribute contains an array of ACEs that are associated with the file system object. Although the client can read and write the acl attribute, the server is responsible for using the ACL to perform access control. The client can use the OPEN or ACCESS operations to check access without modifying or reading data or metadata.

NFSv4.0 ACL属性には、ファイルシステムオブジェクトに関連付けられているACEの配列が含まれています。クライアントはacl属性を読み書きできますが、サーバーはACLを使用してアクセス制御を実行する必要があります。クライアントは、OPENまたはACCESS操作を使用して、データやメタデータを変更したり読み取ったりせずにアクセスを確認できます。

The NFS ACE structure is defined as follows:

NFS ACE構造は次のように定義されます。

typedef uint32_t acetype4;

typedef uint32_t acetype4;

typedef uint32_t aceflag4;

typedef uint32_t aceflag4;

typedef uint32_t acemask4;

typedef uint32_t acemask4;

   struct nfsace4 {
           acetype4                type;
           aceflag4                flag;
           acemask4                access_mask;
           utf8str_mixed           who;

To determine if a request succeeds, the server processes each nfsace4 entry in order. Only ACEs that have a "who" that matches the requester are considered. Each ACE is processed until all of the bits of the requester's access have been ALLOWED. Once a bit (see below) has been ALLOWED by an ACCESS_ALLOWED_ACE, it is no longer considered in the processing of later ACEs. If an ACCESS_DENIED_ACE is encountered where the requester's access still has unALLOWED bits in common with the "access_mask" of the ACE, the request is denied. When the ACL is fully processed, if there are bits in the requester's mask that have not been ALLOWED or DENIED, access is denied.

リクエストが成功したかどうかを判断するために、サーバーは各nfsace4エントリを順番に処理します。要求者に一致する「who」を持つACEのみが考慮されます。各ACEは、要求者のアクセスのすべてのビットが許可されるまで処理されます。 ACCESS_ALLOWED_ACEによってビット(以下を参照)が許可されると、以降のACEの処理では考慮されなくなります。リクエスターのアクセスにACEの「access_mask」と共通のunALLOWEDビットがまだあるACCESS_DENIED_ACEが検出された場合、要求は拒否されます。 ACLが完全に処理されたときに、リクエスタのマスクに許可または拒否されていないビットがある場合、アクセスは拒否されます。

Unlike the ALLOW and DENY ACE types, the ALARM and AUDIT ACE types do not affect a requester's access and instead are for triggering events as a result of a requester's access attempt. Therefore, AUDIT and ALARM ACEs are processed only after processing ALLOW and DENY ACEs.

ALLOWおよびDENY ACEタイプとは異なり、ALARMおよびAUDIT ACEタイプはリクエスターのアクセスに影響せず、リクエスターのアクセス試行の結果としてイベントをトリガーするためのものです。したがって、AUDITおよびALARM ACEは、ALLOWおよびDENY ACEを処理した後でのみ処理されます。

The NFSv4.0 ACL model is quite rich. Some server platforms may provide access control functionality that goes beyond the UNIX-style mode attribute but that is not as rich as the NFS ACL model. So that users can take advantage of this more limited functionality, the server may support the acl attributes by mapping between its ACL model and the NFSv4.0 ACL model. Servers must ensure that the ACL they actually store or enforce is at least as strict as the NFSv4 ACL that was set. It is tempting to accomplish this by rejecting any ACL that falls outside the small set that can be represented accurately. However, such an approach can render ACLs unusable without special client-side knowledge of the server's mapping, which defeats the purpose of having a common NFSv4 ACL protocol. Therefore, servers should accept every ACL that they can without compromising security. To help accomplish this, servers may make a special exception, in the case of unsupported permission bits, to the rule that bits not ALLOWED or DENIED by an ACL must be denied. For example, a UNIX-style server might choose to silently allow read attribute permissions even though an ACL does not explicitly allow those permissions. (An ACL that explicitly denies permission to read attributes should still result in a denial.)

NFSv4.0 ACLモデルは非常に豊富です。一部のサーバープラットフォームは、UNIXスタイルのモード属性を超えるアクセス制御機能を提供しますが、NFS ACLモデルほど豊富ではありません。ユーザーがこのより限定された機能を利用できるように、サーバーはACLモデルとNFSv4.0 ACLモデルの間のマッピングによってacl属性をサポートする場合があります。サーバーは、サーバーが実際に格納または実施するACLが、少なくとも設定されたNFSv4 ACLと同じくらい厳格であることを確認する必要があります。正確に表すことができる小さなセットの外にあるACLを拒否することでこれを実現したくなります。ただし、このようなアプローチでは、サーバー側のマッピングに関するクライアント側の特別な知識がなければ、ACLが使用できなくなる可能性があり、これは一般的なNFSv4 ACLプロトコルを持つ目的に反します。したがって、サーバーはセキュリティを犠牲にすることなく、可能なすべてのACLを受け入れる必要があります。これを実現するために、サーバーは、サポートされていない許可ビットの場合、ACLによって許可または拒否されていないビットを拒否する必要があるという規則に対して、特別な例外を作成する場合があります。たとえば、UNIXスタイルのサーバーは、ACLが明示的にアクセス許可を許可していなくても、読み取り属性アクセス許可をサイレントに許可することを選択する場合があります。 (属性の読み取り権限を明示的に拒否するACLでも、拒否が発生するはずです。)

The situation is complicated by the fact that a server may have multiple modules that enforce ACLs. For example, the enforcement for NFSv4.0 access may be different from, but not weaker than, the enforcement for local access, and both may be different from the enforcement for access through other protocols such as Server Message Block (SMB) [MS-SMB]. So it may be useful for a server to accept an ACL even if not all of its modules are able to support it.

サーバーには、ACLを適用する複数のモジュールがある場合があるため、状況は複雑です。たとえば、NFSv4.0アクセスの施行は、ローカルアクセスの施行とは異なる場合がありますが、それよりも弱くはなく、どちらもサーバーメッセージブロック(SMB)などのその他のプロトコルを介したアクセスの施行とは異なる場合があります[MS- SMB]。そのため、すべてのモジュールがACLをサポートできるわけではない場合でも、サーバーがACLを受け入れると便利な場合があります。

The guiding principle with regard to NFSv4 access is that the server must not accept ACLs that give an appearance of more restricted access to a file than what is actually enforced.

NFSv4アクセスに関する基本原則は、サーバーは、実際に適用されているものよりもファイルへのアクセスが制限されているように見えるACLを受け入れてはならないということです。 ACE Type ACEタイプ

The constants used for the type field (acetype4) are as follows:


   const ACE4_ACCESS_ALLOWED_ACE_TYPE      = 0x00000000;
   const ACE4_ACCESS_DENIED_ACE_TYPE       = 0x00000001;
   const ACE4_SYSTEM_AUDIT_ACE_TYPE        = 0x00000002;
   const ACE4_SYSTEM_ALARM_ACE_TYPE        = 0x00000003;

All four bit types are permitted in the acl attribute.


   | Value                        | Abbreviation | Description         |
   | ACE4_ACCESS_ALLOWED_ACE_TYPE | ALLOW        | Explicitly grants   |
   |                              |              | the access defined  |
   |                              |              | in acemask4 to the  |
   |                              |              | file or directory.  |
   |                              |              |                     |
   | ACE4_ACCESS_DENIED_ACE_TYPE  | DENY         | Explicitly denies   |
   |                              |              | the access defined  |
   |                              |              | in acemask4 to the  |
   |                              |              | file or directory.  |
   |                              |              |                     |
   | ACE4_SYSTEM_AUDIT_ACE_TYPE   | AUDIT        | LOG (in a system-   |
   |                              |              | dependent way) any  |
   |                              |              | access attempt to a |
   |                              |              | file or directory   |
   |                              |              | that uses any of    |
   |                              |              | the access methods  |
   |                              |              | specified in        |
   |                              |              | acemask4.           |
   |                              |              |                     |
   | ACE4_SYSTEM_ALARM_ACE_TYPE   | ALARM        | Generate a system   |
   |                              |              | ALARM (system       |
   |                              |              | dependent) when any |
   |                              |              | access attempt is   |
   |                              |              | made to a file or   |
   |                              |              | directory for the   |
   |                              |              | access methods      |
   |                              |              | specified in        |
   |                              |              | acemask4.           |

The "Abbreviation" column denotes how the types will be referred to throughout the rest of this section.

「略語」の列は、このセクションの残りの部分でタイプがどのように参照されるかを示しています。 Attribute 13: aclsupport 属性13:aclsupport

A server need not support all of the above ACE types. This attribute indicates which ACE types are supported for the current file system. The bitmask constants used to represent the above definitions within the aclsupport attribute are as follows:

サーバーは、上記のACEタイプのすべてをサポートする必要はありません。この属性は、現在のファイルシステムでサポートされているACEタイプを示します。 aclsupport属性内の上記の定義を表すために使用されるビットマスク定数は次のとおりです。

   const ACL4_SUPPORT_ALLOW_ACL    = 0x00000001;
   const ACL4_SUPPORT_DENY_ACL     = 0x00000002;
   const ACL4_SUPPORT_AUDIT_ACL    = 0x00000004;
   const ACL4_SUPPORT_ALARM_ACL    = 0x00000008;

Servers that support either the ALLOW or DENY ACE type SHOULD support both ALLOW and DENY ACE types.

ALLOWまたはDENY ACEタイプをサポートするサーバーは、ALLOWおよびDENY ACEタイプの両方をサポートする必要があります(SHOULD)。

Clients should not attempt to set an ACE unless the server claims support for that ACE type. If the server receives a request to set an ACE that it cannot store, it MUST reject the request with NFS4ERR_ATTRNOTSUPP. If the server receives a request to set an ACE that it can store but cannot enforce, the server SHOULD reject the request with NFS4ERR_ATTRNOTSUPP.

サーバーがそのACEタイプのサポートを要求しない限り、クライアントはACEを設定しないでください。サーバーは、格納できないACEを設定する要求を受信した場合、NFS4ERR_ATTRNOTSUPPを使用して要求を拒否する必要があります。サーバーが格納できるが強制できないACEを設定する要求を受信した場合、サーバーはNFS4ERR_ATTRNOTSUPPを使用して要求を拒否する必要があります(SHOULD)。 ACE Access Mask ACEアクセスマスク

The bitmask constants used for the access mask field are as follows:


   const ACE4_READ_DATA            = 0x00000001;
   const ACE4_LIST_DIRECTORY       = 0x00000001;
   const ACE4_WRITE_DATA           = 0x00000002;
   const ACE4_ADD_FILE             = 0x00000002;
   const ACE4_APPEND_DATA          = 0x00000004;
   const ACE4_ADD_SUBDIRECTORY     = 0x00000004;
   const ACE4_READ_NAMED_ATTRS     = 0x00000008;
   const ACE4_WRITE_NAMED_ATTRS    = 0x00000010;
   const ACE4_EXECUTE              = 0x00000020;
   const ACE4_DELETE_CHILD         = 0x00000040;
   const ACE4_READ_ATTRIBUTES      = 0x00000080;
   const ACE4_WRITE_ATTRIBUTES     = 0x00000100;
   const ACE4_DELETE               = 0x00010000;
   const ACE4_READ_ACL             = 0x00020000;
   const ACE4_WRITE_ACL            = 0x00040000;
   const ACE4_WRITE_OWNER          = 0x00080000;
   const ACE4_SYNCHRONIZE          = 0x00100000;

Note that some masks have coincident values -- for example, ACE4_READ_DATA and ACE4_LIST_DIRECTORY. The mask entries ACE4_LIST_DIRECTORY, ACE4_ADD_FILE, and ACE4_ADD_SUBDIRECTORY are intended to be used with directory objects, while ACE4_READ_DATA, ACE4_WRITE_DATA, and ACE4_APPEND_DATA are intended to be used with non-directory objects.

ACE4_READ_DATAとACE4_LIST_DIRECTORYなど、一部のマスクには一致する値があることに注意してください。マスクエントリACE4_LIST_DIRECTORY、ACE4_ADD_FILE、およびACE4_ADD_SUBDIRECTORYは、ディレクトリオブジェクトでの使用を目的としていますが、ACE4_READ_DATA、ACE4_WRITE_DATA、およびACE4_APPEND_DATAは、非ディレクトリオブジェクトでの使用を目的としています。 Discussion of Mask Attributes マスク属性の説明



Operation(s) affected:








Permission to read the data of the file.


Servers SHOULD allow a user the ability to read the data of the file when only the ACE4_EXECUTE access mask bit is set.




Operation(s) affected:






Permission to list the contents of a directory.




Operation(s) affected:






SETATTR of size




Permission to modify a file's data.




Operation(s) affected:












Permission to add a new file in a directory. The CREATE operation is affected when nfs_ftype4 is NF4LNK, NF4BLK, NF4CHR, NF4SOCK, or NF4FIFO. (NF4DIR is not listed because it is covered by ACE4_ADD_SUBDIRECTORY.) OPEN is affected when used to create a regular file. LINK and RENAME are always affected.

ディレクトリに新しいファイルを追加する権限。 nfs_ftype4がNF4LNK、NF4BLK、NF4CHR、NF4SOCK、またはNF4FIFOの場合、CREATE操作が影響を受けます。 (NF4DIRはACE4_ADD_SUBDIRECTORYでカバーされているため、リストに含まれていません。)OPENは、通常のファイルの作成に使用された場合に影響を受けます。 LINKとRENAMEは常に影響を受けます。



Operation(s) affected:






SETATTR of size




The ability to modify a file's data, but only starting at EOF. This allows for the notion of append-only files, by allowing ACE4_APPEND_DATA and denying ACE4_WRITE_DATA to the same user or group. If a file has an ACL such as the one described above and a WRITE request is made for somewhere other than EOF, the server SHOULD return NFS4ERR_ACCESS.




Operation(s) affected:








Permission to create a subdirectory in a directory. The CREATE operation is affected when nfs_ftype4 is NF4DIR. The RENAME operation is always affected.

ディレクトリにサブディレクトリを作成する権限。 nfs_ftype4がNF4DIRの場合、CREATE操作が影響を受けます。 RENAME操作は常に影響を受けます。



Operation(s) affected:






Permission to read the named attributes of a file or to look up the named attributes directory. OPENATTR is affected when it is not used to create a named attribute directory. This is when 1) createdir is TRUE but a named attribute directory already exists or 2) createdir is FALSE.

ファイルの名前付き属性を読み取る権限、または名前付き属性ディレクトリを検索する権限。 OPENATTRは、名前付き属性ディレクトリの作成に使用されない場合に影響を受けます。これは、1)createdirがTRUEであるが、名前付き属性ディレクトリがすでに存在する場合、または2)createdirがFALSEの場合です。



Operation(s) affected:






Permission to write the named attributes of a file or to create a named attribute directory. OPENATTR is affected when it is used to create a named attribute directory. This is when createdir is TRUE and no named attribute directory exists. The ability to check whether or not a named attribute directory exists depends on the ability to look it up; therefore, users also need the ACE4_READ_NAMED_ATTRS permission in order to create a named attribute directory.

ファイルの名前付き属性を書き込む権限、または名前付き属性ディレクトリを作成する権限。 OPENATTRを使用して名前付き属性ディレクトリを作成すると、OPENATTRが影響を受けます。これは、createdirがTRUEで、名前付き属性ディレクトリが存在しない場合です。名前付き属性ディレクトリが存在するかどうかを確認する機能は、それを検索する機能に依存します。したがって、名前付き属性ディレクトリを作成するには、ユーザーにもACE4_READ_NAMED_ATTRS権限が必要です。



Operation(s) affected:






Permission to execute a file.


Servers SHOULD allow a user the ability to read the data of the file when only the ACE4_EXECUTE access mask bit is set. This is because there is no way to execute a file without reading the contents. Though a server may treat ACE4_EXECUTE and ACE4_READ_DATA bits identically when deciding to permit a READ operation, it SHOULD still allow the two bits to be set independently in ACLs and MUST distinguish between them when replying to ACCESS operations. In particular, servers SHOULD NOT silently turn on one of the two bits when the other is set, as that would make it impossible for the client to correctly enforce the distinction between read and execute permissions.


As an example, following a SETATTR of the following ACL:




A subsequent GETATTR of ACL for that file SHOULD return:




Rather than:





Operation(s) affected:
















Permission to traverse/search a directory.




Operation(s) affected:








Permission to delete a file or directory within a directory. See Section for information on how ACE4_DELETE and ACE4_DELETE_CHILD interact.

ディレクトリ内のファイルまたはディレクトリを削除する権限。 ACE4_DELETEとACE4_DELETE_CHILDがどのように相互作用するかについては、セクション6.を参照してください。



Operation(s) affected:


GETATTR of file system object attributes










The ability to read basic attributes (non-ACLs) of a file. On a UNIX system, basic attributes can be thought of as the stat-level attributes. Allowing this access mask bit would mean the entity can execute "ls -l" and stat. If a READDIR operation requests attributes, this mask must be allowed for the READDIR to succeed.

ファイルの基本属性(非ACL)を読み取る機能。 UNIXシステムでは、基本的な属性は統計レベルの属性と考えることができます。このアクセスマスクビットを許可すると、エンティティは "ls -l"およびstatを実行できます。 READDIR操作が属性を要求する場合、READDIRが成功するには、このマスクが許可されている必要があります。



Operation(s) affected:


SETATTR of time_access_set, time_backup, time_create, time_modify_set, mimetype, hidden, and system




Permission to change the times associated with a file or directory to an arbitrary value. Also, permission to change the mimetype, hidden and system attributes. A user having ACE4_WRITE_DATA or ACE4_WRITE_ATTRIBUTES will be allowed to set the times associated with a file to the current server time.

ファイルまたはディレクトリに関連付けられた時間を任意の値に変更する権限。また、mimetype、hidden、およびsystem属性を変更する権限。 ACE4_WRITE_DATAまたはACE4_WRITE_ATTRIBUTESを持つユーザーは、ファイルに関連付けられた時刻を現在のサーバー時刻に設定できます。



Operation(s) affected:






Permission to delete the file or directory. See Section for information on ACE4_DELETE and ACE4_DELETE_CHILD interact.

ファイルまたはディレクトリを削除する権限。 ACE4_DELETEとACE4_DELETE_CHILDの相互作用については、セクション6.を参照してください。



Operation(s) affected:


GETATTR of acl








Permission to read the ACL.




Operation(s) affected:


SETATTR of acl and mode




Permission to write the acl and mode attributes.




Operation(s) affected:


SETATTR of owner and owner_group




Permission to write the owner and owner_group attributes. On UNIX systems, this is the ability to execute chown() and chgrp().

ownerおよびowner_group属性を書き込む権限。 UNIXシステムでは、これはchown()およびchgrp()を実行する機能です。



Operation(s) affected:






Permission to use the file object as a synchronization primitive for interprocess communication. This permission is not enforced or interpreted by the NFSv4.0 server on behalf of the client.


Typically, the ACE4_SYNCHRONIZE permission is only meaningful on local file systems, i.e., file systems not accessed via NFSv4.0. The reason that the permission bit exists is that some operating environments, such as Windows, use ACE4_SYNCHRONIZE.


For example, if a client copies a file that has ACE4_SYNCHRONIZE set from a local file system to an NFSv4.0 server, and then later copies the file from the NFSv4.0 server to a local file system, it is likely that if ACE4_SYNCHRONIZE was set in the original file, the client will want it set in the second copy. The first copy will not have the permission set unless the NFSv4.0 server has the means to set the ACE4_SYNCHRONIZE bit. The second copy will not have the permission set unless the NFSv4.0 server has the means to retrieve the ACE4_SYNCHRONIZE bit.

たとえば、クライアントがACE4_SYNCHRONIZEが設定されたファイルをローカルファイルシステムからNFSv4.0サーバーにコピーし、その後NFSv4.0サーバーからローカルファイルシステムにファイルをコピーした場合、ACE4_SYNCHRONIZEが元のファイルに設定した場合、クライアントは2番目のコピーに設定する必要があります。 NFSv4.0サーバーがACE4_SYNCHRONIZEビットを設定する手段を備えていない限り、最初のコピーには権限が設定されません。 NFSv4.0サーバーがACE4_SYNCHRONIZEビットを取得する手段を備えていない限り、2番目のコピーには権限が設定されません。

Server implementations need not provide the granularity of control that is implied by this list of masks. For example, POSIX-based systems might not distinguish ACE4_APPEND_DATA (the ability to append to a file) from ACE4_WRITE_DATA (the ability to modify existing contents); both masks would be tied to a single "write" permission. When such a server returns attributes to the client, it would show both ACE4_APPEND_DATA and ACE4_WRITE_DATA if and only if the write permission is enabled.


If a server receives a SETATTR request that it cannot accurately implement, it should err in the direction of more restricted access, except in the previously discussed cases of execute and read. For example, suppose a server cannot distinguish overwriting data from appending new data, as described in the previous paragraph. If a client submits an ALLOW ACE where ACE4_APPEND_DATA is set but ACE4_WRITE_DATA is not (or vice versa), the server should either turn off ACE4_APPEND_DATA or reject the request with NFS4ERR_ATTRNOTSUPP.

サーバーが正確に実装できないSETATTR要求を受け取った場合、前述の実行と読み取りの場合を除いて、より制限されたアクセスの方向にエラーが発生するはずです。たとえば、前の段落で説明したように、サーバーがデータの上書きと新しいデータの追加を区別できないとします。クライアントがACE4_APPEND_DATAが設定されているがACE4_WRITE_DATAが設定されていない(またはその逆の)ALLOW ACEを送信する場合、サーバーはACE4_APPEND_DATAをオフにするか、NFS4ERR_ATTRNOTSUPPで要求を拒否する必要があります。 ACE4_DELETE versus ACE4_DELETE_CHILD ACE4_DELETEとACE4_DELETE_CHILD

Two access mask bits govern the ability to delete a directory entry: ACE4_DELETE on the object itself (the "target") and ACE4_DELETE_CHILD on the containing directory (the "parent").


Many systems also take the "sticky bit" (MODE4_SVTX) on a directory to allow unlink only to a user that owns either the target or the parent; on some such systems, the decision also depends on whether the target is writable.


Servers SHOULD allow unlink if either ACE4_DELETE is permitted on the target or ACE4_DELETE_CHILD is permitted on the parent. (Note that this is true even if the parent or target explicitly denies the other of these permissions.)

ターゲットでACE4_DELETEが許可されているか、親でACE4_DELETE_CHILDが許可されている場合、サーバーはリンク解除を許可する必要があります(SHOULD)。 (これは、親またはターゲットがこれらの権限の他方を明示的に拒否した場合でも当てはまります。)

If the ACLs in question neither explicitly ALLOW nor DENY either of the above, and if MODE4_SVTX is not set on the parent, then the server SHOULD allow the removal if and only if ACE4_ADD_FILE is permitted. In the case where MODE4_SVTX is set, the server may also require the remover to own either the parent or the target, or may require the target to be writable.

問題のACLが上記のいずれかを明示的に許可も拒否もしない場合、および親にMODE4_SVTXが設定されていない場合、サーバーは、ACE4_ADD_FILEが許可されている場合に限り、削除を許可する必要があります(SHOULD)。 MODE4_SVTXが設定されている場合、サーバーはリムーバーが親またはターゲットのいずれかを所有することを要求するか、ターゲットが書き込み可能であることを要求する場合があります。

This allows servers to support something close to traditional UNIX-like semantics, with ACE4_ADD_FILE taking the place of the write bit.

これにより、サーバーは、書き込みビットの代わりにACE4_ADD_FILEを使用して、従来のUNIXに似たセマンティクスに近いものをサポートできます。 ACE flag ACEフラグ

The bitmask constants used for the flag field are as follows:


   const ACE4_FILE_INHERIT_ACE             = 0x00000001;
   const ACE4_DIRECTORY_INHERIT_ACE        = 0x00000002;
   const ACE4_NO_PROPAGATE_INHERIT_ACE     = 0x00000004;
   const ACE4_INHERIT_ONLY_ACE             = 0x00000008;
   const ACE4_SUCCESSFUL_ACCESS_ACE_FLAG   = 0x00000010;
   const ACE4_FAILED_ACCESS_ACE_FLAG       = 0x00000020;
   const ACE4_IDENTIFIER_GROUP             = 0x00000040;

A server need not support any of these flags. If the server supports flags that are similar to, but not exactly the same as, these flags, the implementation may define a mapping between the protocol-defined flags and the implementation-defined flags.


For example, suppose a client tries to set an ACE with ACE4_FILE_INHERIT_ACE set but not ACE4_DIRECTORY_INHERIT_ACE. If the server does not support any form of ACL inheritance, the server should reject the request with NFS4ERR_ATTRNOTSUPP. If the server supports a single "inherit ACE" flag that applies to both files and directories, the server may reject the request (i.e., requiring the client to set both the file and directory inheritance flags). The server may also accept the request and silently turn on the ACE4_DIRECTORY_INHERIT_ACE flag.

たとえば、クライアントがACE4_FILE_INHERIT_ACEを設定してACE4_DIRECTORY_INHERIT_ACEを設定せずにACEを設定しようとしているとします。サーバーがどの形式のACL継承もサポートしていない場合、サーバーはNFS4ERR_ATTRNOTSUPPを使用して要求を拒否する必要があります。サーバーがファイルとディレクトリの両方に適用される単一の「継承ACE」フラグをサポートしている場合、サーバーはリクエストを拒否する可能性があります(つまり、クライアントにファイルとディレクトリの両方の継承フラグを設定するよう要求する)。サーバーは要求を受け入れ、サイレントにACE4_DIRECTORY_INHERIT_ACEフラグをオンにすることもできます。 Discussion of Flag Bits フラグビットの説明

ACE4_FILE_INHERIT_ACE Any non-directory file in any subdirectory will get this ACE inherited.


ACE4_DIRECTORY_INHERIT_ACE Can be placed on a directory and indicates that this ACE should be added to each new directory created. If this flag is set in an ACE in an ACL attribute to be set on a non-directory file system object, the operation attempting to set the ACL SHOULD fail with NFS4ERR_ATTRNOTSUPP.


ACE4_INHERIT_ONLY_ACE Can be placed on a directory but does not apply to the directory; ALLOW and DENY ACEs with this bit set do not affect access to the directory, and AUDIT and ALARM ACEs with this bit set do not trigger log or alarm events. Such ACEs only take effect once they are applied (with this bit cleared) to newly created files and directories as specified by the above two flags. If this flag is present on an ACE, but neither ACE4_DIRECTORY_INHERIT_ACE nor ACE4_FILE_INHERIT_ACE is present, then an operation attempting to set such an attribute SHOULD fail with NFS4ERR_ATTRNOTSUPP.

ACE4_INHERIT_ONLY_ACEディレクトリに配置できますが、ディレクトリには適用されません。このビットが設定されたALLOWおよびDENY ACEは、ディレクトリへのアクセスに影響を与えません。また、このビットが設定されたAUDITおよびALARM ACEは、ログまたはアラームイベントをトリガーしません。このようなACEは、上記の2つのフラグで指定されたように、新しく作成されたファイルとディレクトリに適用された(このビットがクリアされている)場合にのみ有効になります。このフラグがACEに存在するが、ACE4_DIRECTORY_INHERIT_ACEもACE4_FILE_INHERIT_ACEも存在しない場合、そのような属性を設定しようとする操作はNFS4ERR_ATTRNOTSUPPで失敗する必要があります(SHOULD)。

ACE4_NO_PROPAGATE_INHERIT_ACE Can be placed on a directory. This flag tells the server that inheritance of this ACE should stop at newly created child directories.




ACE4_FAILED_ACCESS_ACE_FLAG The ACE4_SUCCESSFUL_ACCESS_ACE_FLAG (SUCCESS) and ACE4_FAILED_ACCESS_ACE_FLAG (FAILED) flag bits may be set only on ACE4_SYSTEM_AUDIT_ACE_TYPE (AUDIT) and ACE4_SYSTEM_ALARM_ACE_TYPE (ALARM) ACE types. If, during the processing of the file's ACL, the server encounters an AUDIT or ALARM ACE that matches the principal attempting the OPEN, the server notes that fact and notes the presence, if any, of the SUCCESS and FAILED flags encountered in the AUDIT or ALARM ACE. Once the server completes the ACL processing, it then notes if the operation succeeded or failed. If the operation succeeded, and if the SUCCESS flag was set for a matching AUDIT or ALARM ACE, then the appropriate AUDIT or ALARM event occurs. If the operation failed, and if the FAILED flag was set for the matching AUDIT or ALARM ACE, then the appropriate AUDIT or ALARM event occurs. Either or both of the SUCCESS or FAILED can be set, but if neither is set, the AUDIT or ALARM ACE is not useful.

ACE4_FAILED_ACCESS_ACE_FLAG ACE4_SUCCESSFUL_ACCESS_ACE_FLAG(SUCCESS)およびACE4_FAILED_ACCESS_ACE_FLAG(FAILED)フラグビットは、ACE4_SYSTEM_AUDIT_ACE_TYPE(AUDIT)およびACE4_SYSTEM_ALARM_ACE_TYPE(。ファイルのACLの処理中に、サーバーがOPENを試行するプリンシパルと一致するAUDITまたはALARM ACEを検出すると、サーバーはその事実を記録し、AUDITまたはFAILEDフラグで発生したSUCCESSおよびFAILEDフラグの存在を記録します。アラームエース。サーバーはACL処理を完了すると、操作が成功したか失敗したかを記録します。操作が成功し、一致するAUDITまたはALARM ACEにSUCCESSフラグが設定されている場合、適切なAUDITまたはALARMイベントが発生します。操作が失敗し、一致するAUDITまたはALARM ACEにFAILEDフラグが設定されている場合、適切なAUDITまたはALARMイベントが発生します。 SUCCESSまたはFAILEDのいずれかまたは両方を設定できますが、どちらも設定されていない場合、AUDITまたはALARM ACEは役に立ちません。

The previously described processing applies to ACCESS operations even when they return NFS4_OK. For the purposes of AUDIT and ALARM, we consider an ACCESS operation to be a "failure" if it fails to return a bit that was requested and supported.

前述の処理は、NFS4_OKを返す場合でも、ACCESS操作に適用されます。 AUDITとALARMの目的のために、要求されサポートされているビットを返すことができない場合、ACCESS操作は「失敗」と見なされます。

ACE4_IDENTIFIER_GROUP Indicates that the "who" refers to a GROUP as defined under UNIX or a GROUP ACCOUNT as defined under Windows. Clients and servers MUST ignore the ACE4_IDENTIFIER_GROUP flag on ACEs with a who value equal to one of the special identifiers outlined in Section

ACE4_IDENTIFIER_GROUP「who」がUNIXで定義されたGROUPまたはWindowsで定義されたGROUP ACCOUNTを指すことを示します。クライアントとサーバーは、セクション6.2.1.5で概説されている特別な識別子の1つに等しいwho値を持つACEのACE4_IDENTIFIER_GROUPフラグを無視する必要があります。 ACE Who エースフー

The who field of an ACE is an identifier that specifies the principal or principals to whom the ACE applies. It may refer to a user or a group, with the flag bit ACE4_IDENTIFIER_GROUP specifying which.


There are several special identifiers that need to be understood universally, rather than in the context of a particular DNS domain. Some of these identifiers cannot be understood when an NFS client accesses the server but have meaning when a local process accesses the file. The ability to display and modify these permissions is permitted over NFS, even if none of the access methods on the server understand the identifiers.


   | Who           | Description                                       |
   | OWNER         | The owner of the file.                            |
   | GROUP         | The group associated with the file.               |
   | EVERYONE      | The world, including the owner and owning group.  |
   | INTERACTIVE   | Accessed from an interactive terminal.            |
   | NETWORK       | Accessed via the network.                         |
   | DIALUP        | Accessed as a dialup user to the server.          |
   | BATCH         | Accessed from a batch job.                        |
   | ANONYMOUS     | Accessed without any authentication.              |
   | AUTHENTICATED | Any authenticated user (opposite of ANONYMOUS).   |
   | SERVICE       | Access from a system service.                     |

Table 5: Special Identifiers


To avoid conflict, these special identifiers are distinguished by an appended "@" and should appear in the form "xxxx@" (with no domain name after the "@") -- for example, ANONYMOUS@.

競合を回避するために、これらの特別な識別子は「@」が付加されて区別され、「xxxx @」(「@」の後にドメイン名はありません)の形式で表示されます(例:ANONYMOUS @)。

The ACE4_IDENTIFIER_GROUP flag MUST be ignored on entries with these special identifiers. When encoding entries with these special identifiers, the ACE4_IDENTIFIER_GROUP flag SHOULD be set to zero.

これらの特別な識別子を持つエントリでは、ACE4_IDENTIFIER_GROUPフラグを無視する必要があります。これらの特別な識別子でエントリをエンコードするとき、ACE4_IDENTIFIER_GROUPフラグはゼロに設定されるべきです(SHOULD)。 Discussion of EVERYONE@ EVERYONE @の議論

It is important to note that "EVERYONE@" is not equivalent to the UNIX "other" entity. This is because, by definition, UNIX "other" does not include the owner or owning group of a file. "EVERYONE@" means literally everyone, including the owner or owning group.

「EVERYONE @」はUNIXの「その他」のエンティティと同等ではないことに注意することが重要です。これは、UNIXの「その他」にファイルの所有者または所有グループが含まれていないためです。 「EVERYONE @」は、所有者または所有グループを含む文字通り全員を意味します。

6.2.2. Attribute 33: mode
6.2.2. 属性33:モード

The NFSv4.0 mode attribute is based on the UNIX mode bits. The following bits are defined:


   const MODE4_SUID = 0x800;  /* set user id on execution */
   const MODE4_SGID = 0x400;  /* set group id on execution */
   const MODE4_SVTX = 0x200;  /* save text even after use */
   const MODE4_RUSR = 0x100;  /* read permission: owner */
   const MODE4_WUSR = 0x080;  /* write permission: owner */
   const MODE4_XUSR = 0x040;  /* execute permission: owner */
   const MODE4_RGRP = 0x020;  /* read permission: group */
   const MODE4_WGRP = 0x010;  /* write permission: group */
   const MODE4_XGRP = 0x008;  /* execute permission: group */
   const MODE4_ROTH = 0x004;  /* read permission: other */
   const MODE4_WOTH = 0x002;  /* write permission: other */
   const MODE4_XOTH = 0x001;  /* execute permission: other */

Bits MODE4_RUSR, MODE4_WUSR, and MODE4_XUSR apply to the principal identified in the owner attribute. Bits MODE4_RGRP, MODE4_WGRP, and MODE4_XGRP apply to principals identified in the owner_group attribute but who are not identified in the owner attribute. Bits MODE4_ROTH, MODE4_WOTH, and MODE4_XOTH apply to any principal that does not match that in the owner attribute and does not have a group matching that of the owner_group attribute.


Bits within the mode other than those specified above are not defined by this protocol. A server MUST NOT return bits other than those defined above in a GETATTR or READDIR operation, and it MUST return NFS4ERR_INVAL if bits other than those defined above are set in a SETATTR, CREATE, OPEN, VERIFY, or NVERIFY operation.


6.3. Common Methods
6.3. 一般的な方法

The requirements in this section will be referred to in future sections, especially Section 6.4.


6.3.1. Interpreting an ACL
6.3.1. ACLの解釈 Server Considerations サーバーに関する考慮事項

The server uses the algorithm described in Section 6.2.1 to determine whether an ACL allows access to an object. However, the ACL may not be the sole determiner of access. For example:


o In the case of a file system exported as read-only, the server may deny write permissions even though an object's ACL grants it.

o 読み取り専用としてエクスポートされたファイルシステムの場合、オブジェクトのACLで許可されていても、サーバーは書き込み権限を拒否することがあります。

o Server implementations MAY grant ACE4_WRITE_ACL and ACE4_READ_ACL permissions to prevent a situation from arising in which there is no valid way to ever modify the ACL.

o サーバーの実装は、ACE4_WRITE_ACLおよびACE4_READ_ACLアクセス許可を付与して、ACLを変更する有効な方法がない状況が発生しないようにすることができます(MAY)。

o All servers will allow a user the ability to read the data of the file when only the execute permission is granted (i.e., if the ACL denies the user ACE4_READ_DATA access and allows the user ACE4_EXECUTE, the server will allow the user to read the data of the file).

o すべてのサーバーは、実行権限のみが付与されている場合に、ユーザーがファイルのデータを読み取ることができるようにします(つまり、ACLがユーザーACE4_READ_DATAアクセスを拒否し、ユーザーACE4_EXECUTEを許可すると、サーバーはユーザーにデータの読み取りを許可しますファイル)。

o Many servers have the notion of owner-override, in which the owner of the object is allowed to override accesses that are denied by the ACL. This may be helpful, for example, to allow users continued access to open files on which the permissions have changed.

o 多くのサーバーには、オブジェクトの所有者がACLによって拒否されたアクセスをオーバーライドすることが許可されている、所有者オーバーライドの概念があります。これは、たとえば、アクセス許可が変更された開いているファイルにユーザーが引き続きアクセスできるようにする場合に役立ちます。

o Many servers have the notion of a "superuser" that has privileges beyond an ordinary user. The superuser may be able to read or write data or metadata in ways that would not be permitted by the ACL.

o 多くのサーバーには、通常のユーザー以上の特権を持つ「スーパーユーザー」という概念があります。スーパーユーザーは、ACLで許可されていない方法でデータまたはメタデータを読み書きできる場合があります。 Client Considerations クライアントの考慮事項

Clients SHOULD NOT do their own access checks based on their interpretation of the ACL but rather use the OPEN and ACCESS operations to do access checks. This allows the client to act on the results of having the server determine whether or not access should be granted based on its interpretation of the ACL.


Clients must be aware of situations in which an object's ACL will define a certain access even though the server will not have adequate information to enforce it. For example, the server has no way of determining whether a particular OPEN reflects a user's open for read access or is done as part of executing the file in question. In such situations, the client needs to do its part in the enforcement of access as defined by the ACL. To do this, the client will send the appropriate ACCESS operation (or use a cached previous determination) prior to servicing the request of the user or application in order to determine whether the user or application should be granted the access requested. For examples in which the ACL may define accesses that the server does not enforce, see Section

クライアントは、オブジェクトのACLが特定のアクセスを定義する状況を認識している必要がありますが、サーバーはそれを実施するための適切な情報を持っていません。たとえば、サーバーには、特定のOPENがユーザーの読み取りアクセスのためのオープンを反映しているか、問題のファイルの実行の一部として行われているかを判断する方法がありません。このような状況では、クライアントは、ACLで定義されているアクセスの実施においてその役割を果たす必要があります。これを行うために、ユーザーまたはアプリケーションに要求されたアクセスを許可するかどうかを決定するために、クライアントはユーザーまたはアプリケーションの要求を処理する前に適切なACCESS操作を送信します(またはキャッシュされた以前の決定を使用します)。 ACLがサーバーが実施しないアクセスを定義する例については、セクション6.3.1.1を参照してください。

6.3.2. Computing a mode Attribute from an ACL
6.3.2. ACLからのモード属性の計算

The following method can be used to calculate the MODE4_R*, MODE4_W*, and MODE4_X* bits of a mode attribute, based upon an ACL.

次のメソッドは、ACLに基づいて、モード属性のMODE4_R *、MODE4_W *、およびMODE4_X *ビットを計算するために使用できます。

First, for each of the special identifiers OWNER@, GROUP@, and EVERYONE@, evaluate the ACL in order, considering only ALLOW and DENY ACEs for the identifier EVERYONE@ and for the identifier under consideration. The result of the evaluation will be an NFSv4 ACL mask showing exactly which bits are permitted to that identifier.

最初に、特別な識別子OWNER @、GROUP @、およびEVERYONE @のそれぞれについて、順番にACLを評価します。識別子EVERYONE @および考慮中の識別子のALLOWおよびDENY ACEのみを考慮します。評価の結果は、その識別子に許可されているビットを正確に示すNFSv4 ACLマスクになります。

Then translate the calculated mask for OWNER@, GROUP@, and EVERYONE@ into mode bits for the user, group, and other, respectively, as follows:

次に、OWNER @、GROUP @、およびEVERYONE @の計算されたマスクを、次のように、それぞれユーザー、グループ、およびその他のモードビットに変換します。

1. Set the read bit (MODE4_RUSR, MODE4_RGRP, or MODE4_ROTH) if and only if ACE4_READ_DATA is set in the corresponding mask.

1. Set the read bit (MODE4_RUSR, MODE4_RGRP, or MODE4_ROTH) if and only if ACE4_READ_DATA is set in the corresponding mask.

2. Set the write bit (MODE4_WUSR, MODE4_WGRP, or MODE4_WOTH) if and only if ACE4_WRITE_DATA and ACE4_APPEND_DATA are both set in the corresponding mask.

2. ACE4_WRITE_DATAとACE4_APPEND_DATAの両方が対応するマスクに設定されている場合にのみ、書き込みビット(MODE4_WUSR、MODE4_WGRP、またはMODE4_WOTH)を設定します。

3. Set the execute bit (MODE4_XUSR, MODE4_XGRP, or MODE4_XOTH), if and only if ACE4_EXECUTE is set in the corresponding mask.

3. ACE4_EXECUTEが対応するマスクで設定されている場合にのみ、実行ビット(MODE4_XUSR、MODE4_XGRP、またはMODE4_XOTH)を設定します。 Discussion 討論

Some server implementations also add bits permitted to named users and groups to the group bits (MODE4_RGRP, MODE4_WGRP, and MODE4_XGRP).


Implementations are discouraged from doing this, because it has been found to cause confusion for users who see members of a file's group denied access that the mode bits appear to allow. (The presence of DENY ACEs may also lead to such behavior, but DENY ACEs are expected to be more rarely used.)

モードビットが許可しているように見えるファイルのグループのメンバーがアクセスを拒否しているのを見るユーザーに混乱を引き起こすことが判明しているため、実装はこれを行わないようにしてください。 (DENY ACEの存在もこのような動作につながる可能性がありますが、DENY ACEが使用されることはほとんどありません。)

The same user confusion seen when fetching the mode also results if setting the mode does not effectively control permissions for the owner, group, and other users; this motivates some of the requirements that follow.


6.4. Requirements
6.4. 必要条件

The server that supports both mode and ACL must take care to synchronize the MODE4_*USR, MODE4_*GRP, and MODE4_*OTH bits with the ACEs that have respective who fields of "OWNER@", "GROUP@", and "EVERYONE@" so that the client can see that semantically equivalent access permissions exist whether the client asks for just the ACL or any of the owner, owner_group, and mode attributes.

モードとACLの両方をサポートするサーバーは、MODE4_ * USR、MODE4_ * GRP、およびMODE4_ * OTHビットを、「OWNER @」、「GROUP @」、および「EVERYONE @」のそれぞれのwhoフィールドを持つACEと同期するように注意する必要があります"クライアントがACLだけを要求するか、owner、owner_group、mode属性のいずれを要求するかに関係なく、意味的に同等のアクセス許可が存在することをクライアントが確認できるようにします。

Many requirements refer to Section 6.3.2, but note that the methods have behaviors specified with "SHOULD". This is intentional, to avoid invalidating existing implementations that compute the mode according to the withdrawn POSIX ACL draft ([P1003.1e]), rather than by actual permissions on owner, group, and other.

多くの要件は6.3.2項を参照していますが、メソッドには「SHOULD」で指定された動作があることに注意してください。これは、所有者、グループなどに対する実際の権限ではなく、撤回されたPOSIX ACLドラフト([P1003.1e])に従ってモードを計算する既存の実装が無効になるのを避けるための意図的なものです。

6.4.1. Setting the mode and/or ACL Attributes
6.4.1. モードやACL属性の設定 Setting mode and Not ACL ACLではなく設定モード

When any of the nine low-order mode bits are changed because the mode attribute was set, and no ACL attribute is explicitly set, the acl attribute must be modified in accordance with the updated value of those bits. This must happen even if the value of the low-order bits is the same after the mode is set as before.


Note that any AUDIT or ALARM ACEs are unaffected by changes to the mode.

Note that any AUDIT or ALARM ACEs are unaffected by changes to the mode.

In cases in which the permissions bits are subject to change, the acl attribute MUST be modified such that the mode computed via the method described in Section 6.3.2 yields the low-order nine bits (MODE4_R*, MODE4_W*, MODE4_X*) of the mode attribute as modified by the change attribute. The ACL attributes SHOULD also be modified such that:

許可ビットが変更される可能性がある場合、セクション6.3.2で説明されている方法で計算されたモードが下位9ビット(MODE4_R *、MODE4_W *、MODE4_X *)を生成するように、acl属性を変更する必要があります。 change属性によって変更されたモード属性。 ACL属性は、次のように変更する必要もあります。

1. If MODE4_RGRP is not set, entities explicitly listed in the ACL other than OWNER@ and EVERYONE@ SHOULD NOT be granted ACE4_READ_DATA.

1. If MODE4_RGRP is not set, entities explicitly listed in the ACL other than OWNER@ and EVERYONE@ SHOULD NOT be granted ACE4_READ_DATA.

2. If MODE4_WGRP is not set, entities explicitly listed in the ACL other than OWNER@ and EVERYONE@ SHOULD NOT be granted ACE4_WRITE_DATA or ACE4_APPEND_DATA.

2. MODE4_WGRPが設定されていない場合、OWNER @およびEVERYONE @以外のACLに明示的にリストされているエンティティには、ACE4_WRITE_DATAまたはACE4_APPEND_DATAを付与しないでください。

3. If MODE4_XGRP is not set, entities explicitly listed in the ACL other than OWNER@ and EVERYONE@ SHOULD NOT be granted ACE4_EXECUTE.

3. MODE4_XGRPが設定されていない場合、OWNER @およびEVERYONE @以外のACLに明示的にリストされているエンティティには、ACE4_EXECUTEを付与しないでください。

Access mask bits other than those listed above, appearing in ALLOW ACEs, MAY also be disabled.

ALLOW ACEに表示される上記以外のアクセスマスクビットも無効にできます(MAY)。

Note that ACEs with the flag ACE4_INHERIT_ONLY_ACE set do not affect the permissions of the ACL itself, nor do ACEs of the types AUDIT and ALARM. As such, it is desirable to leave these ACEs unmodified when modifying the ACL attributes.


Also note that the requirement may be met by discarding the acl in favor of an ACL that represents the mode and only the mode. This is permitted, but it is preferable for a server to preserve as much of the ACL as possible without violating the above requirements. Discarding the ACL makes it effectively impossible for a file created with a mode attribute to inherit an ACL (see Section 6.4.3).

また、モードを表し、モードのみを表すACLを優先して、ACLを破棄することで要件が満たされる場合があることに注意してください。これは許可されていますが、サーバーが上記の要件に違反することなく、できるだけ多くのACLを保持することをお勧めします。 ACLを破棄すると、mode属性で作成されたファイルがACLを継承することが事実上不可能になります(6.4.3項を参照)。 Setting ACL and Not mode ACLおよびNotモードの設定

When setting the acl and not setting the mode attribute, the permission bits of the mode need to be derived from the ACL. In this case, the ACL attribute SHOULD be set as given. The nine low-order bits of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) MUST be modified to match the result of the method described in Section 6.3.2. The three high-order bits of the mode (MODE4_SUID, MODE4_SGID, MODE4_SVTX) SHOULD remain unchanged.

aclを設定し、mode属性を設定しない場合、モードの許可ビットはACLから取得する必要があります。この場合、ACL属性は指定されたとおりに設定する必要があります(SHOULD)。モード属性の下位9ビット(MODE4_R *、MODE4_W *、MODE4_X *)は、セクション6.3.2で説明されているメソッドの結果と一致するように変更する必要があります。モードの3つの上位ビット(MODE4_SUID、MODE4_SGID、MODE4_SVTX)は変更されないままにする必要があります。 Setting Both ACL and mode ACLとモードの両方を設定する

When setting both the mode and the acl attribute in the same operation, the attributes MUST be applied in this order: mode, then ACL. The mode-related attribute is set as given, then the ACL attribute is set as given, possibly changing the final mode, as described above in Section

When setting both the mode and the acl attribute in the same operation, the attributes MUST be applied in this order: mode, then ACL. The mode-related attribute is set as given, then the ACL attribute is set as given, possibly changing the final mode, as described above in Section

6.4.2. Retrieving the mode and/or ACL Attributes
6.4.2. モードおよび/またはACL属性の取得

This section applies only to servers that support both the mode and ACL attributes.


Some server implementations may have a concept of "objects without ACLs", meaning that all permissions are granted and denied according to the mode attribute, and that no ACL attribute is stored for that object. If an ACL attribute is requested of such a server, the server SHOULD return an ACL that does not conflict with the mode; that is to say, the ACL returned SHOULD represent the nine low-order bits of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) as described in Section 6.3.2.

Some server implementations may have a concept of "objects without ACLs", meaning that all permissions are granted and denied according to the mode attribute, and that no ACL attribute is stored for that object. If an ACL attribute is requested of such a server, the server SHOULD return an ACL that does not conflict with the mode; that is to say, the ACL returned SHOULD represent the nine low-order bits of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) as described in Section 6.3.2.

For other server implementations, the ACL attribute is always present for every object. Such servers SHOULD store at least the three high-order bits of the mode attribute (MODE4_SUID, MODE4_SGID, MODE4_SVTX). The server SHOULD return a mode attribute if one is requested, and the low-order nine bits of the mode (MODE4_R*, MODE4_W*, MODE4_X*) MUST match the result of applying the method in Section 6.3.2 to the ACL attribute.

他のサーバー実装の場合、ACL属性は常にすべてのオブジェクトに存在します。このようなサーバーは、モード属性(MODE4_SUID、MODE4_SGID、MODE4_SVTX)の少なくとも上位3ビットを格納する必要があります(SHOULD)。モード属性が要求された場合、サーバーはモード属性を返す必要があり(SHOULD)、モードの下位9ビット(MODE4_R *、MODE4_W *、MODE4_X *)は、セクション6.3.2のメソッドをACL属性に適用した結果と一致する必要があります。

6.4.3. Creating New Objects
6.4.3. 新しいオブジェクトの作成

If a server supports any ACL attributes, it may use the ACL attributes on the parent directory to compute an initial ACL attribute for a newly created object. This will be referred to as the inherited ACL within this section. The act of adding one or more ACEs to the inherited ACL that are based upon ACEs in the parent directory's ACL will be referred to as inheriting an ACE within this section.


In the presence or absence of the mode and ACL attributes, the behavior of CREATE and OPEN SHOULD be:

In the presence or absence of the mode and ACL attributes, the behavior of CREATE and OPEN SHOULD be:

1. If just the mode is given in the call:

1. 呼び出しでモードのみが指定されている場合:

In this case, inheritance SHOULD take place, but the mode MUST be applied to the inherited ACL as described in Section, thereby modifying the ACL.


2. If just the ACL is given in the call:

2. 呼び出しでACLのみが指定されている場合:

In this case, inheritance SHOULD NOT take place, and the ACL as defined in the CREATE or OPEN will be set without modification, and the mode modified as in Section

この場合、継承は行われるべきではなく(SHOULD NOT)、CREATEまたはOPENで定義されたACLは変更せずに設定され、モードは6.4.1.2のように変更されます。

3. If both mode and ACL are given in the call:

3. 呼び出しでモードとACLの両方が指定されている場合:

In this case, inheritance SHOULD NOT take place, and both attributes will be set as described in Section

この場合、継承は行われるべきではなく(SHOULD NOT)、両方の属性がセクション6.4.1.3で説明されているように設定されます。

4. If neither mode nor ACL is given in the call:

4. 呼び出しでモードもACLも指定されていない場合:

In the case where an object is being created without any initial attributes at all, e.g., an OPEN operation with an opentype4 of OPEN4_CREATE and a createmode4 of EXCLUSIVE4, inheritance SHOULD NOT take place. Instead, the server SHOULD set permissions to deny all access to the newly created object. It is expected that the appropriate client will set the desired attributes in a subsequent SETATTR operation, and the server SHOULD allow that operation to succeed, regardless of what permissions the object is created with. For example, an empty ACL denies all permissions, but the server should allow the owner's SETATTR to succeed even though WRITE_ACL is implicitly denied.

オブジェクトが初期属性なしで作成されている場合(たとえば、opentype4がOPEN4_CREATEで、createmode4がEXCLUSIVE4であるOPEN操作)、継承は行われません(SHOULD NOT)。代わりに、サーバーは、新しく作成されたオブジェクトへのすべてのアクセスを拒否するアクセス許可を設定する必要があります(SHOULD)。適切なクライアントが後続のSETATTR操作で必要な属性を設定することが期待されており、サーバーは、オブジェクトの作成に使用する権限に関係なく、その操作を成功させる必要があります(SHOULD)。たとえば、空のACLはすべての権限を拒否しますが、WRITE_ACLが暗黙的に拒否されている場合でも、サーバーは所有者のSETATTRを成功させる必要があります。

In other cases, inheritance SHOULD take place, and no modifications to the ACL will happen. The mode attribute, if supported, MUST be as computed via the method described in Section 6.3.2, with the MODE4_SUID, MODE4_SGID, and MODE4_SVTX bits clear. If no inheritable ACEs exist on the parent directory, the rules for creating acl attributes are implementation defined.

他の場合では、継承が行われる必要があり(SHOULD)、ACLへの変更は行われません。サポートされている場合、モード属性は、セクション6.3.2で説明されているメソッドを介して計算され、MODE4_SUID、MODE4_SGID、およびMODE4_SVTXビットがクリアされている必要があります。継承可能なACEが親ディレクトリに存在しない場合、ACL属性の作成規則は実装で定義されます。 The Inherited ACL 継承されたACL

If the object being created is not a directory, the inherited ACL SHOULD NOT inherit ACEs from the parent directory ACL unless the ACE4_FILE_INHERIT_FLAG is set.

作成されるオブジェクトがディレクトリでない場合、継承されたACLは、ACE4_FILE_INHERIT_FLAGが設定されていない限り、親ディレクトリACLからACEを継承してはなりません(SHOULD NOT)。

If the object being created is a directory, the inherited ACL should inherit all inheritable ACEs from the parent directory, i.e., those that have the ACE4_FILE_INHERIT_ACE or ACE4_DIRECTORY_INHERIT_ACE flag set. If the inheritable ACE has ACE4_FILE_INHERIT_ACE set, but ACE4_DIRECTORY_INHERIT_ACE is clear, the inherited ACE on the newly created directory MUST have the ACE4_INHERIT_ONLY_ACE flag set to prevent the directory from being affected by ACEs meant for non-directories.


When a new directory is created, the server MAY split any inherited ACE that is both inheritable and effective (in other words, that has neither ACE4_INHERIT_ONLY_ACE nor ACE4_NO_PROPAGATE_INHERIT_ACE set) into two ACEs -- one with no inheritance flags, and one with ACE4_INHERIT_ONLY_ACE set. This makes it simpler to modify the effective permissions on the directory without modifying the ACE that is to be inherited to the new directory's children.


7. NFS Server Namespace
7. NFSサーバー名前空間
7.1. Server Exports
7.1. サーバーのエクスポート

On a UNIX server, the namespace describes all the files reachable by pathnames under the root directory or "/". On a Windows server, the namespace constitutes all the files on disks named by mapped disk letters. NFS server administrators rarely make the entire server's file system namespace available to NFS clients. More often, portions of the namespace are made available via an "export" feature. In previous versions of the NFS protocol, the root filehandle for each export is obtained through the MOUNT protocol; the client sends a string that identifies an object in the exported namespace, and the server returns the root filehandle for it. The MOUNT protocol supports an EXPORTS procedure that will enumerate the server's exports.

UNIXサーバーでは、ネームスペースは、ルートディレクトリまたは「/」の下のパス名によって到達可能なすべてのファイルを記述します。 Windowsサーバーでは、名前空間は、マップされたディスク文字で名前が付けられたディスク上のすべてのファイルを構成します。 NFSサーバー管理者がサーバーのファイルシステム全体の名前空間をNFSクライアントが利用できるようにすることはほとんどありません。多くの場合、名前空間の一部は、「エクスポート」機能を介して利用可能になります。以前のバージョンのNFSプロトコルでは、各エクスポートのルートファイルハンドルはMOUNTプロトコルを介して取得されました。クライアントはエクスポートされた名前空間のオブジェクトを識別する文字列を送信し、サーバーはそのオブジェクトのルートファイルハンドルを返します。 MOUNTプロトコルは、サーバーのエクスポートを列挙するEXPORTSプロシージャをサポートしています。

7.2. Browsing Exports
7.2. エクスポートの閲覧

The NFSv4 protocol provides a root filehandle that clients can use to obtain filehandles for these exports via a multi-component LOOKUP. A common user experience is to use a graphical user interface (perhaps a file "Open" dialog window) to find a file via progressive browsing through a directory tree. The client must be able to move from one export to another export via single-component, progressive LOOKUP operations.


This style of browsing is not well supported by the NFSv2 and NFSv3 protocols. The client expects all LOOKUP operations to remain within a single-server file system. For example, the device attribute will not change. This prevents a client from taking namespace paths that span exports.


An automounter on the client can obtain a snapshot of the server's namespace using the EXPORTS procedure of the MOUNT protocol. If it understands the server's pathname syntax, it can create an image of the server's namespace on the client. The parts of the namespace that are not exported by the server are filled in with a "pseudo-file system" that allows the user to browse from one mounted file system to another. There is a drawback to this representation of the server's namespace on the client: it is static. If the server administrator adds a new export, the client will be unaware of it.


7.3. Server Pseudo-File System
7.3. サーバー疑似ファイルシステム

NFSv4 servers avoid this namespace inconsistency by presenting all the exports within the framework of a single-server namespace. An NFSv4 client uses LOOKUP and READDIR operations to browse seamlessly from one export to another. Portions of the server namespace that are not exported are bridged via a "pseudo-file system" that provides a view of exported directories only. A pseudo-file system has a unique fsid and behaves like a normal, read-only file system.

NFSv4サーバーは、単一サーバー名前空間のフレームワーク内ですべてのエクスポートを提示することにより、この名前空間の不整合を回避します。 NFSv4クライアントは、LOOKUPおよびREADDIR操作を使用して、1つのエクスポートから別のエクスポートへシームレスにブラウズします。エクスポートされないサーバー名前空間の部分は、エクスポートされたディレクトリのみのビューを提供する「疑似ファイルシステム」を介してブリッジされます。疑似ファイルシステムには固有のfsidがあり、通常の読み取り専用ファイルシステムのように動作します。

Based on the construction of the server's namespace, it is possible that multiple pseudo-file systems may exist. For example:


     /a         pseudo-file system
     /a/b       real file system
     /a/b/c     pseudo-file system
     /a/b/c/d   real file system

Each of the pseudo-file systems are considered separate entities and therefore will have a unique fsid.


7.4. Multiple Roots
7.4. 複数の根

The DOS and Windows operating environments are sometimes described as having "multiple roots". File systems are commonly represented as disk letters. MacOS represents file systems as top-level names. NFSv4 servers for these platforms can construct a pseudo-file system above these root names so that disk letters or volume names are simply directory names in the pseudo-root.

DOSおよびWindowsオペレーティング環境は、「複数のルート」を持つものとして説明されることがあります。ファイルシステムは通常、ディスク文字として表されます。 MacOSは、ファイルシステムをトップレベルの名前として表します。これらのプラットフォーム用のNFSv4サーバーは、これらのルート名の上に疑似ファイルシステムを構築して、ディスク文字またはボリューム名が疑似ルート内の単なるディレクトリ名になるようにすることができます。

7.5. Filehandle Volatility
7.5. ファイルハンドルのボラティリティ

The nature of the server's pseudo-file system is that it is a logical representation of file system(s) available from the server. Therefore, the pseudo-file system is most likely constructed dynamically when the server is first instantiated. It is expected that the pseudo-file system may not have an on-disk counterpart from which persistent filehandles could be constructed. Even though it is preferable that the server provide persistent filehandles for the pseudo-file system, the NFS client should expect that pseudo-file system filehandles are volatile. This can be confirmed by checking the associated "fh_expire_type" attribute for those filehandles in question. If the filehandles are volatile, the NFS client must be prepared to recover a filehandle value (e.g., with a multi-component LOOKUP) when receiving an error of NFS4ERR_FHEXPIRED.


7.6. Exported Root
7.6. エクスポートされたルート

If the server's root file system is exported, one might conclude that a pseudo-file system is not needed. This would be wrong. Assume the following file systems on a server:


     /       disk1  (exported)
     /a      disk2  (not exported)
     /a/b    disk3  (exported)

Because disk2 is not exported, disk3 cannot be reached with simple LOOKUPs. The server must bridge the gap with a pseudo-file system.


7.7. Mount Point Crossing
7.7. マウントポイントクロッシング

The server file system environment may be constructed in such a way that one file system contains a directory that is 'covered' or mounted upon by a second file system. For example:


     /a/b            (file system 1)
     /a/b/c/d        (file system 2)

The pseudo-file system for this server may be constructed to look like:


     /               (placeholder/not exported)
     /a/b            (file system 1)
     /a/b/c/d        (file system 2)

It is the server's responsibility to present the pseudo-file system that is complete to the client. If the client sends a LOOKUP request for the path "/a/b/c/d", the server's response is the filehandle of the file system "/a/b/c/d". In previous versions of the NFS protocol, the server would respond with the filehandle of directory "/a/b/c/d" within the file system "/a/b".

It is the server's responsibility to present the pseudo-file system that is complete to the client. If the client sends a LOOKUP request for the path "/a/b/c/d", the server's response is the filehandle of the file system "/a/b/c/d". In previous versions of the NFS protocol, the server would respond with the filehandle of directory "/a/b/c/d" within the file system "/a/b".

The NFS client will be able to determine if it crosses a server mount point by a change in the value of the "fsid" attribute.


7.8. Security Policy and Namespace Presentation
7.8. セキュリティポリシーと名前空間の表示

Because NFSv4 clients possess the ability to change the security mechanisms used, after determining what is allowed, by using SECINFO the server SHOULD NOT present a different view of the namespace based on the security mechanism being used by a client. Instead, it should present a consistent view and return NFS4ERR_WRONGSEC if an attempt is made to access data with an inappropriate security mechanism.

Because NFSv4 clients possess the ability to change the security mechanisms used, after determining what is allowed, by using SECINFO the server SHOULD NOT present a different view of the namespace based on the security mechanism being used by a client. Instead, it should present a consistent view and return NFS4ERR_WRONGSEC if an attempt is made to access data with an inappropriate security mechanism.

If security considerations make it necessary to hide the existence of a particular file system, as opposed to all of the data within it, the server can apply the security policy of a shared resource in the server's namespace to components of the resource's ancestors. For example:


       /                       (placeholder/not exported)
       /a/b                    (file system 1)
       /a/b/MySecretProject    (file system 2)

The /a/b/MySecretProject directory is a real file system and is the shared resource. Suppose the security policy for /a/b/ MySecretProject is Kerberos with integrity and it is desired to limit knowledge of the existence of this file system. In this case, the server should apply the same security policy to /a/b. This allows for knowledge of the existence of a file system to be secured when desirable.

The /a/b/MySecretProject directory is a real file system and is the shared resource. Suppose the security policy for /a/b/ MySecretProject is Kerberos with integrity and it is desired to limit knowledge of the existence of this file system. In this case, the server should apply the same security policy to /a/b. This allows for knowledge of the existence of a file system to be secured when desirable.

For the case of the use of multiple, disjoint security mechanisms in the server's resources, applying that sort of policy would result in the higher-level file system not being accessible using any security flavor. Therefore, that sort of configuration is not compatible with hiding the existence (as opposed to the contents) from clients using multiple disjoint sets of security flavors.


In other circumstances, a desirable policy is for the security of a particular object in the server's namespace to include the union of all security mechanisms of all direct descendants. A common and convenient practice, unless strong security requirements dictate otherwise, is to make the entire pseudo-file system accessible by all of the valid security mechanisms.


Where there is concern about the security of data on the network, clients should use strong security mechanisms to access the pseudo-file system in order to prevent man-in-the-middle attacks.


8. Multi-Server Namespace
8. マルチサーバー名前空間

NFSv4 supports attributes that allow a namespace to extend beyond the boundaries of a single server. It is RECOMMENDED that clients and servers support construction of such multi-server namespaces. Use of such multi-server namespaces is optional, however, and for many purposes, single-server namespaces are perfectly acceptable. Use of multi-server namespaces can provide many advantages, however, by separating a file system's logical position in a namespace from the (possibly changing) logistical and administrative considerations that result in particular file systems being located on particular servers.


8.1. Location Attributes
8.1. ロケーション属性

NFSv4 contains RECOMMENDED attributes that allow file systems on one server to be associated with one or more instances of that file system on other servers. These attributes specify such file system instances by specifying a server address target (as either a DNS name representing one or more IP addresses, or a literal IP address), together with the path of that file system within the associated single-server namespace.


The fs_locations RECOMMENDED attribute allows specification of the file system locations where the data corresponding to a given file system may be found.

fs_locations RECOMMENDED属性を使用すると、特定のファイルシステムに対応するデータを見つけることができるファイルシステムの場所を指定できます。

8.2. File System Presence or Absence
8.2. ファイルシステムの有無

A given location in an NFSv4 namespace (typically but not necessarily a multi-server namespace) can have a number of file system instance locations associated with it via the fs_locations attribute. There may also be an actual current file system at that location, accessible via normal namespace operations (e.g., LOOKUP). In this case, the file system is said to be "present" at that position in the namespace, and clients will typically use it, reserving use of additional locations specified via the location-related attributes to situations in which the principal location is no longer available.


When there is no actual file system at the namespace location in question, the file system is said to be "absent". An absent file system contains no files or directories other than the root. Any reference to it, except to access a small set of attributes useful in determining alternative locations, will result in an error, NFS4ERR_MOVED. Note that if the server ever returns the error NFS4ERR_MOVED, it MUST support the fs_locations attribute.


While the error name suggests that we have a case of a file system that once was present, and has only become absent later, this is only one possibility. A position in the namespace may be permanently absent with the set of file system(s) designated by the location attributes being the only realization. The name NFS4ERR_MOVED reflects an earlier, more limited conception of its function, but this error will be returned whenever the referenced file system is absent, whether it has moved or simply never existed.

このエラー名は、かつて存在し、後でなくなったファイルシステムのケースがあることを示していますが、これは1つの可能性にすぎません。名前空間内の位置は永続的に存在しない場合があり、ロケーション属性によって指定されたファイルシステムのセットが唯一の実現です。 NFS4ERR_MOVEDという名前は、その機能の以前のより限定された概念を反映していますが、このエラーは、参照されたファイルシステムが存在しないか、移動されたか、単に存在しなかったかに関係なく返されます。

Except in the case of GETATTR-type operations (to be discussed later), when the current filehandle at the start of an operation is within an absent file system, that operation is not performed and the error NFS4ERR_MOVED is returned, to indicate that the file system is absent on the current server.


Because a GETFH cannot succeed if the current filehandle is within an absent file system, filehandles within an absent file system cannot be transferred to the client. When a client does have filehandles within an absent file system, it is the result of obtaining them when the file system was present, and having the file system become absent subsequently.

Because a GETFH cannot succeed if the current filehandle is within an absent file system, filehandles within an absent file system cannot be transferred to the client. When a client does have filehandles within an absent file system, it is the result of obtaining them when the file system was present, and having the file system become absent subsequently.

It should be noted that because the check for the current filehandle being within an absent file system happens at the start of every operation, operations that change the current filehandle so that it is within an absent file system will not result in an error. This allows such combinations as PUTFH-GETATTR and LOOKUP-GETATTR to be used to get attribute information, particularly location attribute information, as discussed below.


8.3. Getting Attributes for an Absent File System
8.3. 存在しないファイルシステムの属性の取得

When a file system is absent, most attributes are not available, but it is necessary to allow the client access to the small set of attributes that are available, and most particularly that which gives information about the correct current locations for this file system, fs_locations.

ファイルシステムが存在しない場合、ほとんどの属性は利用できませんが、利用可能な属性の小さなセットへのクライアントアクセスを許可する必要があります。特に、このファイルシステムの正しい現在の場所に関する情報を提供するfs_locations 。

8.3.1. GETATTR within an Absent File System
8.3.1. 存在しないファイルシステム内でのGETATTR

As mentioned above, an exception is made for GETATTR in that attributes may be obtained for a filehandle within an absent file system. This exception only applies if the attribute mask contains at least the fs_locations attribute bit, which indicates that the client is interested in a result regarding an absent file system. If it is not requested, GETATTR will result in an NFS4ERR_MOVED error.

As mentioned above, an exception is made for GETATTR in that attributes may be obtained for a filehandle within an absent file system. This exception only applies if the attribute mask contains at least the fs_locations attribute bit, which indicates that the client is interested in a result regarding an absent file system. If it is not requested, GETATTR will result in an NFS4ERR_MOVED error.

When a GETATTR is done on an absent file system, the set of supported attributes is very limited. Many attributes, including those that are normally REQUIRED, will not be available on an absent file system. In addition to the fs_locations attribute, the following attributes SHOULD be available on absent file systems. In the case of RECOMMENDED attributes, they should be available at least to the same degree that they are available on present file systems.

When a GETATTR is done on an absent file system, the set of supported attributes is very limited. Many attributes, including those that are normally REQUIRED, will not be available on an absent file system. In addition to the fs_locations attribute, the following attributes SHOULD be available on absent file systems. In the case of RECOMMENDED attributes, they should be available at least to the same degree that they are available on present file systems.

fsid: This attribute should be provided so that the client can determine file system boundaries, including, in particular, the boundary between present and absent file systems. This value must be different from any other fsid on the current server and need have no particular relationship to fsids on any particular destination to which the client might be directed.


mounted_on_fileid: For objects at the top of an absent file system, this attribute needs to be available. Since the fileid is within the present parent file system, there should be no need to reference the absent file system to provide this information.

Mounted_on_fileid:存在しないファイルシステムの最上部にあるオブジェクトの場合、この属性が使用可能である必要があります。 fileidは現在の親ファイルシステム内にあるため、存在しないファイルシステムを参照してこの情報を提供する必要はありません。

Other attributes SHOULD NOT be made available for absent file systems, even when it is possible to provide them. The server should not assume that more information is always better and should avoid gratuitously providing additional information.

他の属性は、それらを提供することが可能な場合でも、存在しないファイルシステムで利用可能にするべきではありません(SHOULD NOT)。サーバーは、より多くの情報が常に優れていると想定してはならず、不必要に追加の情報を提供することは避けてください。

When a GETATTR operation includes a bitmask for the attribute fs_locations, but where the bitmask includes attributes that are not supported, GETATTR will not return an error but will return the mask of the actual attributes supported with the results.


Handling of VERIFY/NVERIFY is similar to GETATTR in that if the attribute mask does not include fs_locations the error NFS4ERR_MOVED will result. It differs in that any appearance in the attribute mask of an attribute not supported for an absent file system (and note that this will include some normally REQUIRED attributes) will also cause an NFS4ERR_MOVED result.

VERIFY / NVERIFYの処理は、属性マスクにfs_locationsが含まれていない場合にエラーNFS4ERR_MOVEDが発生するという点でGETATTRに似ています。これは、存在しないファイルシステムでサポートされていない属性の属性マスクの外観(これには、通常は必須の属性が含まれることに注意してください)も、NFS4ERR_MOVED結果を引き起こす点で異なります。

8.3.2. READDIR and Absent File Systems
8.3.2. READDIRと不在のファイルシステム

A READDIR performed when the current filehandle is within an absent file system will result in an NFS4ERR_MOVED error, since, unlike the case of GETATTR, no such exception is made for READDIR.


Attributes for an absent file system may be fetched via a READDIR for a directory in a present file system, when that directory contains the root directories of one or more absent file systems. In this case, the handling is as follows:


o If the attribute set requested includes fs_locations, then the fetching of attributes proceeds normally, and no NFS4ERR_MOVED indication is returned even when the rdattr_error attribute is requested.

o 要求された属性セットにfs_locationsが含まれている場合、属性のフェッチは正常に行われ、rdattr_error属性が要求された場合でもNFS4ERR_MOVED通知は返されません。

o If the attribute set requested does not include fs_locations, then if the rdattr_error attribute is requested, each directory entry for the root of an absent file system will report NFS4ERR_MOVED as the value of the rdattr_error attribute.

o 要求された属性セットにfs_locationsが含まれていない場合、rdattr_error属性が要求されると、存在しないファイルシステムのルートの各ディレクトリエントリは、rdattr_error属性の値としてNFS4ERR_MOVEDを報告します。

o If the attribute set requested does not include either of the attributes fs_locations or rdattr_error, then the occurrence of the root of an absent file system within the directory will result in the READDIR failing with an NFS4ERR_MOVED error.

o 要求された属性セットに属性fs_locationsまたはrdattr_errorのいずれも含まれていない場合、ディレクトリ内に存在しないファイルシステムのルートが発生すると、READDIRはNFS4ERR_MOVEDエラーで失敗します。

o The unavailability of an attribute because of a file system's absence, even one that is ordinarily REQUIRED, does not result in any error indication. The set of attributes returned for the root directory of the absent file system in that case is simply restricted to those actually available.

o ファイルシステムが存在しないために属性を使用できない場合でも、通常は必須であるにもかかわらず、エラーは表示されません。その場合、存在しないファイルシステムのルートディレクトリに返される属性のセットは、実際に使用可能な属性に制限されます。

8.4. Uses of Location Information
8.4. 位置情報の使用

The location-bearing attribute of fs_locations provides, together with the possibility of absent file systems, a number of important facilities in providing reliable, manageable, and scalable data access.


When a file system is present, these attributes can provide alternative locations, to be used to access the same data, in the event of server failures, communications problems, or other difficulties that make continued access to the current file system impossible or otherwise impractical. Under some circumstances, multiple alternative locations may be used simultaneously to provide higher-performance access to the file system in question. Provision of such alternative locations is referred to as "replication", although there are cases in which replicated sets of data are not in fact present and the replicas are instead different paths to the same data.


When a file system is present and subsequently becomes absent, clients can be given the opportunity to have continued access to their data, at an alternative location. Transfer of the file system contents to the new location is referred to as "migration". See Section 8.4.2 for details.


Alternative locations may be physical replicas of the file system data or alternative communication paths to the same server or, in the case of various forms of server clustering, another server providing access to the same physical file system. The client's responsibilities in dealing with this transition depend on the specific nature of the new access path as well as how and whether data was in fact migrated. These issues will be discussed in detail below.


Where a file system was not previously present, specification of file system location provides a means by which file systems located on one server can be associated with a namespace defined by another server, thus allowing a general multi-server namespace facility. A designation of such a location, in place of an absent file system, is called a "referral".


Because client support for location-related attributes is OPTIONAL, a server may (but is not required to) take action to hide migration and referral events from such clients, by acting as a proxy, for example.


8.4.1. File System Replication
8.4.1. ファイルシステムのレプリケーション

The fs_locations attribute provides alternative locations, to be used to access data in place of, or in addition to, the current file system instance. On first access to a file system, the client should obtain the value of the set of alternative locations by interrogating the fs_locations attribute.


In the event that server failures, communications problems, or other difficulties make continued access to the current file system impossible or otherwise impractical, the client can use the alternative locations as a way to get continued access to its data. Multiple locations may be used simultaneously, to provide higher performance through the exploitation of multiple paths between client and target file system.


Multiple server addresses, whether they are derived from a single entry with a DNS name representing a set of IP addresses or from multiple entries each with its own server address, may correspond to the same actual server.


8.4.2. File System Migration
8.4.2. ファイルシステムの移行

When a file system is present and becomes absent, clients can be given the opportunity to have continued access to their data, at an alternative location, as specified by the fs_locations attribute. Typically, a client will be accessing the file system in question, get an NFS4ERR_MOVED error, and then use the fs_locations attribute to determine the new location of the data.


Such migration can be helpful in providing load balancing or general resource reallocation. The protocol does not specify how the file system will be moved between servers. It is anticipated that a number of different server-to-server transfer mechanisms might be used, with the choice left to the server implementer. The NFSv4 protocol specifies the method used to communicate the migration event between client and server.

このような移行は、ロードバランシングまたは一般的なリソースの再割り当てに役立ちます。プロトコルは、サーバー間でのファイルシステムの移動方法を指定しません。多数の異なるサーバー間転送メカニズムが使用される可能性があり、その選択はサーバー実装者に任されると予想されます。 NFSv4プロトコルは、クライアントとサーバー間の移行イベントの通信に使用される方法を指定します。

When an alternative location is designated as the target for migration, it must designate the same data. Where file systems are writable, a change made on the original file system must be visible on all migration targets. Where a file system is not writable but represents a read-only copy (possibly periodically updated) of a writable file system, similar requirements apply to the propagation of updates. Any change visible in the original file system must already be effected on all migration targets, to avoid any possibility that a client, in effecting a transition to the migration target, will see any reversion in file system state.


8.4.3. Referrals
8.4.3. 紹介

Referrals provide a way of placing a file system in a location within the namespace essentially without respect to its physical location on a given server. This allows a single server or a set of servers to present a multi-server namespace that encompasses file systems located on multiple servers. Some likely uses of this include establishment of site-wide or organization-wide namespaces, or even knitting such together into a truly global namespace.


Referrals occur when a client determines, upon first referencing a position in the current namespace, that it is part of a new file system and that the file system is absent. When this occurs, typically by receiving the error NFS4ERR_MOVED, the actual location or locations of the file system can be determined by fetching the fs_locations attribute.


The location-related attribute may designate a single file system location or multiple file system locations, to be selected based on the needs of the client.


Use of multi-server namespaces is enabled by NFSv4 but is not required. The use of multi-server namespaces and their scope will depend on the applications used and system administration preferences.


Multi-server namespaces can be established by a single server providing a large set of referrals to all of the included file systems. Alternatively, a single multi-server namespace may be administratively segmented with separate referral file systems (on separate servers) for each separately administered portion of the namespace. The top-level referral file system or any segment may use replicated referral file systems for higher availability.


Generally, multi-server namespaces are for the most part uniform, in that the same data made available to one client at a given location in the namespace is made available to all clients at that location.


8.5. Location Entries and Server Identity
8.5. ロケーションエントリとサーバーID

As mentioned above, a single location entry may have a server address target in the form of a DNS name that may represent multiple IP addresses, while multiple location entries may have their own server address targets that reference the same server.


When multiple addresses for the same server exist, the client may assume that for each file system in the namespace of a given server network address, there exist file systems at corresponding namespace locations for each of the other server network addresses. It may do this even in the absence of explicit listing in fs_locations. Such corresponding file system locations can be used as alternative locations, just as those explicitly specified via the fs_locations attribute.

同じサーバーに複数のアドレスが存在する場合、クライアントは、特定のサーバーネットワークアドレスのネームスペース内の各ファイルシステムについて、他の各サーバーネットワークアドレスの対応するネームスペースの場所にファイルシステムが存在すると想定します。 fs_locationsに明示的なリストがない場合でも、これを行うことがあります。このような対応するファイルシステムの場所は、fs_locations属性で明示的に指定されている場所と同じように、代替場所として使用できます。

If a single location entry designates multiple server IP addresses, the client should choose a single one to use. When two server addresses are designated by a single location entry and they correspond to different servers, this normally indicates some sort of misconfiguration, and so the client should avoid using such location entries when alternatives are available. When they are not, clients should pick one of the IP addresses and use it, without using others that are not directed to the same server.

単一の場所エントリが複数のサーバーIPアドレスを指定している場合、クライアントは使用する単一のアドレスを選択する必要があります。 2つのサーバーアドレスが単一の場所エントリによって指定され、それらが異なるサーバーに対応する場合、これは通常、ある種の構成ミスを示しているため、代替が利用可能な場合、クライアントはそのような場所エントリの使用を避ける必要があります。そうでない場合、クライアントは、同じサーバーに向けられていない他のIPアドレスを使用せずに、IPアドレスの1つを選択して使用する必要があります。

8.6. Additional Client-Side Considerations
8.6. 追加のクライアント側の考慮事項

When clients make use of servers that implement referrals, replication, and migration, care should be taken that a user who mounts a given file system that includes a referral or a relocated file system continues to see a coherent picture of that user-side file system despite the fact that it contains a number of server-side file systems that may be on different servers.


One important issue is upward navigation from the root of a server-side file system to its parent (specified as ".." in UNIX), in the case in which it transitions to that file system as a result of referral, migration, or a transition as a result of replication. When the client is at such a point, and it needs to ascend to the parent, it must go back to the parent as seen within the multi-server namespace rather than sending a LOOKUPP operation to the server, which would result in the parent within that server's single-server namespace. In order to do this, the client needs to remember the filehandles that represent such file system roots and use these instead of issuing a LOOKUPP operation to the current server. This will allow the client to present to applications a consistent namespace, where upward navigation and downward navigation are consistent.

One important issue is upward navigation from the root of a server-side file system to its parent (specified as ".." in UNIX), in the case in which it transitions to that file system as a result of referral, migration, or a transition as a result of replication. When the client is at such a point, and it needs to ascend to the parent, it must go back to the parent as seen within the multi-server namespace rather than sending a LOOKUPP operation to the server, which would result in the parent within that server's single-server namespace. In order to do this, the client needs to remember the filehandles that represent such file system roots and use these instead of issuing a LOOKUPP operation to the current server. This will allow the client to present to applications a consistent namespace, where upward navigation and downward navigation are consistent.

Another issue concerns refresh of referral locations. When referrals are used extensively, they may change as server configurations change. It is expected that clients will cache information related to traversing referrals so that future client-side requests are resolved locally without server communication. This is usually rooted in client-side name lookup caching. Clients should periodically purge this data for referral points in order to detect changes in location information.


A potential problem exists if a client were to allow an open-owner to have state on multiple file systems on a server, in that it is unclear how the sequence numbers associated with open-owners are to be dealt with, in the event of transparent state migration. A client can avoid such a situation if it ensures that any use of an open-owner is confined to a single file system.


A server MAY decline to migrate state associated with open-owners that span multiple file systems. In cases in which the server chooses not to migrate such state, the server MUST return NFS4ERR_BAD_STATEID when the client uses those stateids on the new server.

A server MAY decline to migrate state associated with open-owners that span multiple file systems. In cases in which the server chooses not to migrate such state, the server MUST return NFS4ERR_BAD_STATEID when the client uses those stateids on the new server.

The server MUST return NFS4ERR_STALE_STATEID when the client uses those stateids on the old server, regardless of whether migration has occurred or not.

The server MUST return NFS4ERR_STALE_STATEID when the client uses those stateids on the old server, regardless of whether migration has occurred or not.

8.7. Effecting File System Referrals
8.7. ファイルシステムの参照に影響を与える

Referrals are effected when an absent file system is encountered and one or more alternative locations are made available by the fs_locations attribute. The client will typically get an NFS4ERR_MOVED error, fetch the appropriate location information, and proceed to access the file system on a different server, even though it retains its logical position within the original namespace. Referrals differ from migration events in that they happen only when the client has not previously referenced the file system in question (so there is nothing to transition). Referrals can only come into effect when an absent file system is encountered at its root.


The examples given in the sections below are somewhat artificial in that an actual client will not typically do a multi-component lookup but will have cached information regarding the upper levels of the name hierarchy. However, these example are chosen to make the required behavior clear and easy to put within the scope of a small number of requests, without getting unduly into details of how specific clients might choose to cache things.

The examples given in the sections below are somewhat artificial in that an actual client will not typically do a multi-component lookup but will have cached information regarding the upper levels of the name hierarchy. However, these example are chosen to make the required behavior clear and easy to put within the scope of a small number of requests, without getting unduly into details of how specific clients might choose to cache things.

8.7.1. Referral Example (LOOKUP)
8.7.1. Referral Example (LOOKUP)

Let us suppose that the following COMPOUND is sent in an environment in which /this/is/the/path is absent from the target server. This may be for a number of reasons. It may be the case that the file system has moved, or it may be the case that the target server is functioning mainly, or solely, to refer clients to the servers on which various file systems are located.

次のCOMPOUNDが、ターゲットサーバーに/ this / is / the / pathがない環境で送信されたと仮定します。これにはいくつかの理由が考えられます。ファイルシステムが移動した場合や、ターゲットサーバーが主に、または単独で、さまざまなファイルシステムが配置されているサーバーをクライアントに参照するように機能している場合があります。



o LOOKUP "this"

o LOOKUP「これ」

o LOOKUP "is"

o LOOKUP "is"

o LOOKUP "the"

o ルックアップ「the」

o LOOKUP "path"

o LOOKUP "パス"



o GETATTR(fsid, fileid, size, time_modify)

o GETATTR(fsid、fileid、size、time_modify)

Under the given circumstances, the following will be the result:


o PUTROOTFH --> NFS_OK. The current fh is now the root of the pseudo-fs.

o PUTROOTFH-> NFS_OK。現在のfhが疑似fsのルートになりました。

o LOOKUP "this" --> NFS_OK. The current fh is for /this and is within the pseudo-fs.

o LOOKUP "this"-> NFS_OK。現在のfhは/ this用で、疑似fs内にあります。

o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is within the pseudo-fs.

o LOOKUP "is"-> NFS_OK。現在のfhは/ this / is用であり、疑似fs内にあります。

o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and is within the pseudo-fs.

o LOOKUP "the"-> NFS_OK。現在のfhは/ this / is / the用で、疑似fs内にあります。

o LOOKUP "path" --> NFS_OK. The current fh is for /this/is/the/path and is within a new, absent file system, but ... the client will never see the value of that fh.

o LOOKUP "パス"-> NFS_OK。現在のfhは/ this / is / the / path用であり、新しく存在しないファイルシステム内にありますが、クライアントはそのfhの値を見ることができません。

o GETFH --> NFS4ERR_MOVED. Fails, because the current fh is in an absent file system at the start of the operation and the specification makes no exception for GETFH.

o GETFH-> NFS4ERR_MOVED。操作の開始時に現在のfhが存在しないファイルシステムにあり、仕様ではGETFHの例外が発生しないため、失敗します。

o GETATTR(fsid, fileid, size, time_modify). Not executed, because the failure of the GETFH stops the processing of the COMPOUND.

o GETATTR(fsid、fileid、size、time_modify)。 GETFHの失敗によりCOMPOUNDの処理が停止するため、実行されません。

Given the failure of the GETFH, the client has the job of determining the root of the absent file system and where to find that file system, i.e., the server and path relative to that server's root fh. Note here that in this example, the client did not obtain filehandles and attribute information (e.g., fsid) for the intermediate directories, so that it would not be sure where the absent file system starts. It could be the case, for example, that /this/is/the is the root of the moved file system and that the reason that the lookup of "path" succeeded is that the file system was not absent on that operation but was moved between the last LOOKUP and the GETFH (since COMPOUND is not atomic). Even if we had the fsids for all of the intermediate directories, we could have no way of knowing that /this/is/the/path was the root of a new file system, since we don't yet have its fsid.

GETFHが失敗した場合、クライアントは、存在しないファイルシステムのルートと、そのファイルシステムを見つける場所、つまり、サーバーとそのサーバーのルートからの相対パスを決定する役割を果たします。この例では、クライアントが中間ディレクトリのファイルハンドルと属性情報(fsidなど)を取得しなかったため、存在しないファイルシステムがどこから始まるのかがわからないことに注意してください。たとえば、/ this / is / theが移動されたファイルシステムのルートであり、「パス」の検索が成功した理由は、ファイルシステムがその操作に存在せず、移動されたためです。最後のLOOKUPとGETFHの間(COMPOUNDはアトミックではないため)。すべての中間ディレクトリにfsidがあったとしても、まだfsidがないため、/ this / is / the / pathが新しいファイルシステムのルートであることを知る方法がありません。

In order to get the necessary information, let us re-send the chain of LOOKUPs with GETFHs and GETATTRs to at least get the fsids so we can be sure where the appropriate file system boundaries are. The client could choose to get fs_locations at the same time, but in most cases the client will have a good guess as to where the file system boundaries are (because of where NFS4ERR_MOVED was, and was not, received), making the fetching of fs_locations unnecessary.

In order to get the necessary information, let us re-send the chain of LOOKUPs with GETFHs and GETATTRs to at least get the fsids so we can be sure where the appropriate file system boundaries are. The client could choose to get fs_locations at the same time, but in most cases the client will have a good guess as to where the file system boundaries are (because of where NFS4ERR_MOVED was, and was not, received), making the fetching of fs_locations unnecessary.


- The current fh is at the root of the pseudo-fs.

- 現在のfhは疑似fsのルートにあります。

   OP02:  GETATTR(fsid) --> NFS_OK

- Just for completeness. Normally, clients will know the fsid of the pseudo-fs as soon as they establish communication with a server.

- 完全を期すために。通常、クライアントは、サーバーとの通信を確立するとすぐに、疑似fsのfsidを認識します。

   OP03:  LOOKUP "this" --> NFS_OK
   OP04:  GETATTR(fsid) --> NFS_OK

- Get the current fsid to see where the file system boundaries are. The fsid will be that for the pseudo-fs in this example, so no boundary.

- 現在のfsidを取得して、ファイルシステムの境界がどこにあるかを確認します。 fsidは、この例の疑似fsのfsidになるため、境界はありません。

   OP05:  GETFH --> NFS_OK

- The current fh is for /this and is within the pseudo-fs.

- 現在のfhは/ this用で、疑似fs内にあります。

   OP06:  LOOKUP "is" --> NFS_OK

- The current fh is for /this/is and is within the pseudo-fs.

- The current fh is for /this/is and is within the pseudo-fs.

   OP07:  GETATTR(fsid) --> NFS_OK

- Get the current fsid to see where the file system boundaries are. The fsid will be that for the pseudo-fs in this example, so no boundary.

- 現在のfsidを取得して、ファイルシステムの境界がどこにあるかを確認します。 fsidは、この例の疑似fsのfsidになるため、境界はありません。

   OP08:  GETFH --> NFS_OK

- The current fh is for /this/is and is within the pseudo-fs.

- 現在のfhは/ this / is用であり、疑似fs内にあります。

   OP09:  LOOKUP "the" --> NFS_OK

- The current fh is for /this/is/the and is within the pseudo-fs.

- 現在のfhは/ this / is / the用で、疑似fs内にあります。

   OP10:  GETATTR(fsid) --> NFS_OK

- Get the current fsid to see where the file system boundaries are. The fsid will be that for the pseudo-fs in this example, so no boundary.

- 現在のfsidを取得して、ファイルシステムの境界がどこにあるかを確認します。 fsidは、この例の疑似fsのfsidになるため、境界はありません。

   OP11:  GETFH --> NFS_OK

- The current fh is for /this/is/the and is within the pseudo-fs.

- The current fh is for /this/is/the and is within the pseudo-fs.

   OP12:  LOOKUP "path" --> NFS_OK

- The current fh is for /this/is/the/path and is within a new, absent file system, but ...

- 現在のfhは/ this / is / the / path用であり、新しく存在しないファイルシステム内にありますが...

- The client will never see the value of that fh.

- The client will never see the value of that fh.

   OP13:  GETATTR(fsid, fs_locations) --> NFS_OK

- We are getting the fsid to know where the file system boundaries are. In this operation, the fsid will be different than that of the parent directory (which in turn was retrieved in OP10). Note that the fsid we are given will not necessarily be preserved at the new location. That fsid might be different, and in fact the fsid we have for this file system might be a valid fsid of a different file system on that new server.

- We are getting the fsid to know where the file system boundaries are. In this operation, the fsid will be different than that of the parent directory (which in turn was retrieved in OP10). Note that the fsid we are given will not necessarily be preserved at the new location. That fsid might be different, and in fact the fsid we have for this file system might be a valid fsid of a different file system on that new server.

- In this particular case, we are pretty sure anyway that what has moved is /this/is/the/path rather than /this/is/the since we have the fsid of the latter and it is that of the pseudo-fs, which presumably cannot move. However, in other examples, we might not have this kind of information to rely on (e.g., /this/is/the might be a non-pseudo-file system separate from /this/is/the/path), so we need to have other reliable source information on the boundary of the file system that is moved. If, for example, the file system /this/is had moved, we would have a case of migration rather than referral, and once the boundaries of the migrated file system were clear we could fetch fs_locations.

- この特定のケースでは、移動したものが/ this / is / theではなく/ this / is / the / pathであると確信しています。後者のfsidと疑似fsのfsidがあるためです。おそらく移動できません。ただし、他の例では、この種の情報を利用できない場合があります(たとえば、/ this / is / theは/ this / is / the / pathとは別の疑似ファイルシステムである可能性があります)。移動するファイルシステムの境界に他の信頼できるソース情報を保持する。たとえば、ファイルシステム/ this / isが移動された場合、参照ではなく移行のケースがあり、移行されたファイルシステムの境界が明確になれば、fs_locationsをフェッチできます。

- We are fetching fs_locations because the fact that we got an NFS4ERR_MOVED at this point means that this is most likely a referral and we need the destination. Even if it is the case that /this/is/the is a file system that has migrated, we will still need the location information for that file system.

- この時点でNFS4ERR_MOVEDを取得したという事実は、これがおそらく参照であり、宛先が必要であることを意味するため、fs_locationsをフェッチしています。 / this / is / theが移行したファイルシステムである場合でも、そのファイルシステムの場所情報が必要です。


- Fails because current fh is in an absent file system at the start of the operation, and the specification makes no exception for GETFH. Note that this means the server will never send the client a filehandle from within an absent file system.

- 操作の開始時に現在のfhが存在しないファイルシステムにあり、仕様ではGETFHの例外が発生しないため、失敗します。これは、存在しないファイルシステム内からサーバーがクライアントにファイルハンドルを送信しないことを意味します。

Given the above, the client knows where the root of the absent file system is (/this/is/the/path) by noting where the change of fsid occurred (between "the" and "path"). The fs_locations attribute also gives the client the actual location of the absent file system so that the referral can proceed. The server gives the client the bare minimum of information about the absent file system so that there will be very little scope for problems of conflict between information sent by the referring server and information of the file system's home. No filehandles and very few attributes are present on the referring server, and the client can treat those it receives as transient information with the function of enabling the referral.

上記の場合、クライアントは、fsidの変更が発生した場所(「the」と「path」の間)に注目することにより、存在しないファイルシステムのルートがどこにあるか(/ this / is / the / path)を認識します。 fs_locations属性は、クライアントに不在のファイルシステムの実際の場所も提供するため、参照を続行できます。サーバーはクライアントに、存在しないファイルシステムに関する最低限の情報を提供するため、参照サーバーによって送信された情報とファイルシステムのホームの情報との間の競合の問題が生じる可能性はほとんどありません。参照サーバーにはファイルハンドルはなく、属性はほとんどありません。クライアントは、参照を有効にする機能を使用して、受け取った属性を一時的な情報として扱うことができます。

8.7.2. Referral Example (READDIR)
8.7.2. 紹介例(READDIR)

Another context in which a client may encounter referrals is when it does a READDIR on a directory in which some of the subdirectories are the roots of absent file systems.


Suppose such a directory is read as follows:




o LOOKUP "this"

o LOOKUP「これ」

o LOOKUP "is"

o LOOKUP "is"

o LOOKUP "the"

o ルックアップ「the」

o READDIR(fsid, size, time_modify, mounted_on_fileid) In this case, because rdattr_error is not requested, fs_locations is not requested, and some of the attributes cannot be provided, the result will be an NFS4ERR_MOVED error on the READDIR, with the detailed results as follows:

o READDIR(fsid、size、time_modify、mounted_on_fileid)この場合、rdattr_errorは要求されず、fs_locationsは要求されず、一部の属性が提供されないため、結果はREADDIRでNFS4ERR_MOVEDエラーとなり、詳細な結果が表示されます。次のように:

o PUTROOTFH --> NFS_OK. The current fh is at the root of the pseudo-fs.

o PUTROOTFH-> NFS_OK。現在のfhは疑似fsのルートにあります。

o LOOKUP "this" --> NFS_OK. The current fh is for /this and is within the pseudo-fs.

o LOOKUP "this"-> NFS_OK。現在のfhは/ this用で、疑似fs内にあります。

o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is within the pseudo-fs.

o LOOKUP "is"-> NFS_OK。現在のfhは/ this / is用であり、疑似fs内にあります。

o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and is within the pseudo-fs.

o LOOKUP "the"-> NFS_OK。現在のfhは/ this / is / the用で、疑似fs内にあります。

o READDIR(fsid, size, time_modify, mounted_on_fileid) --> NFS4ERR_MOVED. Note that the same error would have been returned if /this/is/the had migrated, but it is returned because the directory contains the root of an absent file system.

o READDIR(fsid、サイズ、time_modify、mounted_on_fileid)-> NFS4ERR_MOVED。 / this / is / theが移行された場合も同じエラーが返されますが、ディレクトリには存在しないファイルシステムのルートが含まれているため、このエラーが返されます。

So now suppose that we re-send with rdattr_error:




o LOOKUP "this"

o LOOKUP「これ」

o LOOKUP "is"

o LOOKUP "is"

o LOOKUP "the"

o ルックアップ「the」

o READDIR(rdattr_error, fsid, size, time_modify, mounted_on_fileid)

o READDIR(rdattr_error、fsid、size、time_modify、mounted_on_fileid)

The results will be:


o PUTROOTFH --> NFS_OK. The current fh is at the root of the pseudo-fs.

o PUTROOTFH-> NFS_OK。現在のfhは疑似fsのルートにあります。

o LOOKUP "this" --> NFS_OK. The current fh is for /this and is within the pseudo-fs.

o LOOKUP "this"-> NFS_OK。現在のfhは/ this用で、疑似fs内にあります。

o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is within the pseudo-fs.

o LOOKUP "is"-> NFS_OK。現在のfhは/ this / is用であり、疑似fs内にあります。

o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and is within the pseudo-fs.

o LOOKUP "the"-> NFS_OK。現在のfhは/ this / is / the用で、疑似fs内にあります。

o READDIR(rdattr_error, fsid, size, time_modify, mounted_on_fileid) --> NFS_OK. The attributes for the directory entry with the component named "path" will only contain rdattr_error with the value NFS4ERR_MOVED, together with an fsid value and a value for mounted_on_fileid.

o READDIR(rdattr_error、fsid、size、time_modify、mounted_on_fileid)-> NFS_OK。 「path」という名前のコンポーネントを持つディレクトリエントリの属性には、fsid値とMounted_on_fileidの値とともに、値NFS4ERR_MOVEDのrdattr_errorのみが含まれます。

So suppose we do another READDIR to get fs_locations (although we could have used a GETATTR directly, as in Section 8.7.1):




o LOOKUP "this"

o LOOKUP「これ」

o LOOKUP "is"

o LOOKUP "is"

o LOOKUP "the"

o ルックアップ「the」

o READDIR(rdattr_error, fs_locations, mounted_on_fileid, fsid, size, time_modify)

o READDIR(rdattr_error、fs_locations、mounted_on_fileid、fsid、size、time_modify)

The results would be:


o PUTROOTFH --> NFS_OK. The current fh is at the root of the pseudo-fs.

o PUTROOTFH-> NFS_OK。現在のfhは疑似fsのルートにあります。

o LOOKUP "this" --> NFS_OK. The current fh is for /this and is within the pseudo-fs.

o LOOKUP "this"-> NFS_OK。現在のfhは/ this用で、疑似fs内にあります。

o LOOKUP "is" --> NFS_OK. The current fh is for /this/is and is within the pseudo-fs.

o LOOKUP "is"-> NFS_OK。現在のfhは/ this / is用であり、疑似fs内にあります。

o LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the and is within the pseudo-fs.

o LOOKUP "the"-> NFS_OK。現在のfhは/ this / is / the用で、疑似fs内にあります。

o READDIR(rdattr_error, fs_locations, mounted_on_fileid, fsid, size, time_modify) --> NFS_OK. The attributes will be as shown below.

o READDIR(rdattr_error、fs_locations、mounted_on_fileid、fsid、size、time_modify)-> NFS_OK。属性は以下のようになります。

The attributes for the directory entry with the component named "path" will only contain:


o rdattr_error (value: NFS_OK)

o rdattr_error(値:NFS_OK)

o fs_locations

o fs_locations

o mounted_on_fileid (value: unique fileid within referring file system)

o Mounted_on_fileid(値:参照ファイルシステム内の一意のファイルID)

o fsid (value: unique value within referring server) The attributes for entry "path" will not contain size or time_modify, because these attributes are not available within an absent file system.

o fsid(値:参照サーバー内の一意の値)エントリ "path"の属性には、サイズやtime_modifyは含まれません。これらの属性は、存在しないファイルシステム内では使用できないためです。

8.8. The Attribute fs_locations
8.8. The Attribute fs_locations

The fs_locations attribute is defined by both fs_location4 (Section 2.2.6) and fs_locations4 (Section 2.2.7). It is used to represent the location of a file system by providing a server name and the path to the root of the file system within that server's namespace. When a set of servers have corresponding file systems at the same path within their namespaces, an array of server names may be provided. An entry in the server array is a UTF-8 string and represents one of a traditional DNS host name, IPv4 address, IPv6 address, or a zero-length string. A zero-length string SHOULD be used to indicate the current address being used for the RPC. It is not a requirement that all servers that share the same rootpath be listed in one fs_location4 instance. The array of server names is provided for convenience. Servers that share the same rootpath may also be listed in separate fs_location4 entries in the fs_locations attribute.

fs_locations属性は、fs_location4(セクション2.2.6)とfs_locations4(セクション2.2.7)の両方で定義されます。これは、サーバー名とそのサーバーの名前空間内のファイルシステムのルートへのパスを提供することにより、ファイルシステムの場所を表すために使用されます。一連のサーバーの名前空間内の同じパスに対応するファイルシステムがある場合、サーバー名の配列を指定できます。サーバー配列のエントリはUTF-8文字列であり、従来のDNSホスト名、IPv4アドレス、IPv6アドレス、または長さゼロの文字列の1つを表します。 RPCに使用されている現在のアドレスを示すには、長さがゼロの文字列を使用する必要があります(SHOULD)。同じrootpathを共有するすべてのサーバーを1つのfs_location4インスタンスにリストする必要はありません。サーバー名の配列は、便宜上提供されています。同じルートパスを共有するサーバーは、fs_locations属性の個別のfs_location4エントリにリストされる場合もあります。

The fs_locations4 data type and fs_locations attribute contain an array of such locations. Since the namespace of each server may be constructed differently, the fs_root field is provided. The path represented by the fs_root represents the location of the file system in the current server's namespace, i.e., that of the server from which the fs_locations attribute was obtained. The fs_root path is meant to aid the client by clearly referencing the root of the file system whose locations are being reported, no matter what object within the current file system the current filehandle designates. The fs_root is simply the pathname the client used to reach the object on the current server (i.e., the object to which the fs_locations attribute applies).

fs_locations4データ型とfs_locations属性には、そのような場所の配列が含まれています。各サーバーの名前空間は異なる方法で構築される可能性があるため、fs_rootフィールドが提供されます。 fs_rootで表されるパスは、現在のサーバーの名前空間内のファイルシステムの場所、つまり、fs_locations属性の取得元のサーバーの場所を表します。 fs_rootパスは、現在のファイルハンドルが指定する現在のファイルシステム内のオブジェクトに関係なく、場所が報告されているファイルシステムのルートを明確に参照することにより、クライアントを支援することを目的としています。 fs_rootは、クライアントが現在のサーバー上のオブジェクト(つまり、fs_locations属性が適用されるオブジェクト)に到達するために使用したパス名です。

When the fs_locations attribute is interrogated and there are no alternative file system locations, the server SHOULD return a zero-length array of fs_location4 structures, together with a valid fs_root.


As an example, suppose there is a replicated file system located at two servers (servA and servB). At servA, the file system is located at path /a/b/c. At servB, the file system is located at path /x/y/z. If the client were to obtain the fs_locations value for the directory at /a/b/c/d, it might not necessarily know that the file system's root is located in servA's namespace at /a/b/c. When the client switches to servB, it will need to determine that the directory it first referenced at servA is now represented by the path /x/y/z/d on servB. To facilitate this, the fs_locations attribute provided by servA would have an fs_root value of /a/b/c and two entries in fs_locations. One entry in fs_locations will be for itself (servA), and the other will be for servB with a path of /x/y/z. With this information, the client is able to substitute /x/y/z for /a/b/c at the beginning of its access path and construct /x/y/z/d to use for the new server.

例として、2つのサーバー(servAとservB)に複製されたファイルシステムがあるとします。 servAでは、ファイルシステムはパス/ a / b / cにあります。 servBでは、ファイルシステムはパス/ x / y / zにあります。クライアントが/ a / b / c / dにあるディレクトリのfs_locations値を取得する場合、ファイルシステムのルートが/ a / b / cにあるservAのネームスペースにあることを必ずしも認識していない場合があります。クライアントがservBに切り替わるとき、servAで最初に参照されたディレクトリがservBのパス/ x / y / z / dで表されていることを確認する必要があります。これを容易にするために、servAによって提供されるfs_locations属性は、fs_root値が/ a / b / cであり、fs_locationsに2つのエントリがあります。 fs_locationsの1つのエントリはそれ自体(servA)用で、もう1つのエントリは/ x / y / zのパスを持つservB用です。この情報を使用して、クライアントはアクセスパスの先頭で/ a / b / cを/ x / y / zに置き換え、新しいサーバーに使用する/ x / y / z / dを構築できます。

Note that there is no requirement that the number of components in each rootpath be the same; there is no relation between the number of components in the rootpath or fs_root, and none of the components in each rootpath and fs_root have to be the same. In the above example, we could have had a third element in the locations array, with server equal to "servC" and rootpath equal to "/I/II", and a fourth element in the locations array, with server equal to "servD" and rootpath equal to "/aleph/beth/gimel/daleth/he".

各rootpathのコンポーネント数が同じである必要はないことに注意してください。ルートパスまたはfs_rootのコンポーネント数には関係がなく、各rootpathとfs_rootのコンポーネントが同じである必要はありません。上記の例では、サーバーが "servC"でルートパスが "/ I / II"の3番目の要素と、サーバーが "servD"の4番目の要素を、locations配列で持つことができます。 "およびrootpathは" / aleph / beth / gimel / daleth / he "に等しい。

The relationship between an fs_root and a rootpath is that the client replaces the pathname indicated in the fs_root for the current server for the substitute indicated in the rootpath for the new server.

The relationship between an fs_root and a rootpath is that the client replaces the pathname indicated in the fs_root for the current server for the substitute indicated in the rootpath for the new server.

For an example of a referred or migrated file system, suppose there is a file system located at serv1. At serv1, the file system is located at /az/buky/vedi/glagoli. The client finds that the object at glagoli has migrated (or is a referral). The client gets the fs_locations attribute, which contains an fs_root of /az/buky/vedi/ glagoli, and one element in the locations array, with server equal to serv2, and rootpath equal to /izhitsa/fita. The client replaces /az/buky/vedi/glagoli with /izhitsa/fita and uses the latter pathname on serv2.

参照または移行されたファイルシステムの例として、serv1にファイルシステムがあるとします。 serv1では、ファイルシステムは/ az / buky / vedi / glagoliにあります。クライアントは、glagoliのオブジェクトが移行した(または紹介である)ことを発見しました。クライアントはfs_locations属性を取得します。これには、/ az / buky / vedi / glagoliのfs_rootと、locations配列の1つの要素が含まれます。サーバーはserv2、ルートパスは/ izhitsa / fitaです。クライアントは/ az / buky / vedi / glagoliを/ izhitsa / fitaに置き換え、serv2で後者のパス名を使用します。

Thus, the server MUST return an fs_root that is equal to the path the client used to reach the object to which the fs_locations attribute applies. Otherwise, the client cannot determine the new path to use on the new server.


9. File Locking and Share Reservations
9. ファイルのロックと共有の予約

Integrating locking into the NFS protocol necessarily causes it to be stateful. With the inclusion of share reservations, the protocol becomes substantially more dependent on state than the traditional combination of NFS and NLM (Network Lock Manager) [xnfs]. There are three components to making this state manageable:


o clear division between client and server

o クライアントとサーバーの明確な区別

o ability to reliably detect inconsistency in state between client and server

o クライアントとサーバー間の状態の不整合を確実に検出する機能

o simple and robust recovery mechanisms

o シンプルで堅牢な回復メカニズム

In this model, the server owns the state information. The client requests changes in locks, and the server responds with the changes made. Non-client-initiated changes in locking state are infrequent. The client receives prompt notification of such changes and can adjust its view of the locking state to reflect the server's changes.


Individual pieces of state created by the server and passed to the client at its request are represented by 128-bit stateids. These stateids may represent a particular open file, a set of byte-range locks held by a particular owner, or a recallable delegation of privileges to access a file in particular ways or at a particular location.


In all cases, there is a transition from the most general information that represents a client as a whole to the eventual lightweight stateid used for most client and server locking interactions. The details of this transition will vary with the type of object, but it always starts with a client ID.


To support Win32 share reservations, it is necessary to atomically OPEN or CREATE files and apply the appropriate locks in the same operation. Having a separate share/unshare operation would not allow correct implementation of the Win32 OpenFile API. In order to correctly implement share semantics, the previous NFS protocol mechanisms used when a file is opened or created (LOOKUP, CREATE, ACCESS) need to be replaced. The NFSv4 protocol has an OPEN operation that subsumes the NFSv3 methodology of LOOKUP, CREATE, and ACCESS. However, because many operations require a filehandle, the traditional LOOKUP is preserved to map a filename to a filehandle without establishing state on the server. The policy of granting access or modifying files is managed by the server based on the client's state. These mechanisms can implement policy ranging from advisory only locking to full mandatory locking.

Win32共有予約をサポートするには、ファイルをアトミックにOPENまたはCREATEし、同じ操作で適切なロックを適用する必要があります。個別の共有/共有解除操作があると、Win32 OpenFile APIを正しく実装できません。共有セマンティクスを正しく実装するには、ファイルを開いたり作成したりするときに使用されていた以前のNFSプロトコルメカニズム(LOOKUP、CREATE、ACCESS)を置き換える必要があります。 NFSv4プロトコルには、LOOKUP、CREATE、およびACCESSのNFSv3方法論を包含するOPEN操作があります。ただし、多くの操作にはファイルハンドルが必要なため、サーバーで状態を確立せずにファイル名をファイルハンドルにマップするために、従来のLOOKUPが保持されます。アクセスの許可またはファイルの変更のポリシーは、クライアントの状態に基づいてサーバーによって管理されます。これらのメカニズムは、アドバイザリーのみのロックから完全な必須ロックまでのポリシーを実装できます。

9.1. Opens and Byte-Range Locks
9.1. オープンおよびバイト範囲ロック

It is assumed that manipulating a byte-range lock is rare when compared to READ and WRITE operations. It is also assumed that server restarts and network partitions are relatively rare. Therefore, it is important that the READ and WRITE operations have a lightweight mechanism to indicate if they possess a held lock. A byte-range lock request contains the heavyweight information required to establish a lock and uniquely define the owner of the lock.


The following sections describe the transition from the heavyweight information to the eventual stateid used for most client and server locking and lease interactions.


9.1.1. Client ID
9.1.1. クライアントID

For each LOCK request, the client must identify itself to the server. This is done in such a way as to allow for correct lock identification and crash recovery. A sequence of a SETCLIENTID operation followed by a SETCLIENTID_CONFIRM operation is required to establish the identification onto the server. Establishment of identification by a new incarnation of the client also has the effect of immediately breaking any leased state that a previous incarnation of the client might have had on the server, as opposed to forcing the new client incarnation to wait for the leases to expire. Breaking the lease state amounts to the server removing all lock, share reservation, and, where the server is not supporting the CLAIM_DELEGATE_PREV claim type, all delegation state associated with the same client with the same identity. For a discussion of delegation state recovery, see Section 10.2.1.


Owners of opens and owners of byte-range locks are separate entities and remain separate even if the same opaque arrays are used to designate owners of each. The protocol distinguishes between open-owners (represented by open_owner4 structures) and lock-owners (represented by lock_owner4 structures).


Both sorts of owners consist of a clientid and an opaque owner string. For each client, the set of distinct owner values used with that client constitutes the set of owners of that type, for the given client.


Each open is associated with a specific open-owner, while each byte-range lock is associated with a lock-owner and an open-owner, the latter being the open-owner associated with the open file under which the LOCK operation was done.


Client identification is encapsulated in the following structure:


   struct nfs_client_id4 {
           verifier4       verifier;
           opaque          id<NFS4_OPAQUE_LIMIT>;

The first field, verifier, is a client incarnation verifier that is used to detect client reboots. Only if the verifier is different from that which the server has previously recorded for the client (as identified by the second field of the structure, id) does the server start the process of canceling the client's leased state.


The second field, id, is a variable-length string that uniquely defines the client.


There are several considerations for how the client generates the id string:


o The string should be unique so that multiple clients do not present the same string. The consequences of two clients presenting the same string range from one client getting an error to one client having its leased state abruptly and unexpectedly canceled.

o 複数のクライアントが同じ文字列を提示しないように、文字列は一意である必要があります。 2つのクライアントが同じ文字列を提示することによる影響は、1つのクライアントがエラーを取得することから、1つのクライアントがリース状態を突然予期せずにキャンセルすることまでさまざまです。

o The string should be selected so the subsequent incarnations (e.g., reboots) of the same client cause the client to present the same string. The implementer is cautioned against an approach that requires the string to be recorded in a local file because this precludes the use of the implementation in an environment where there is no local disk and all file access is from an NFSv4 server.

o 同じクライアントの後続のインカネーション(再起動など)がクライアントに同じ文字列を表示させるように、文字列を選択する必要があります。ローカルディスクがなく、すべてのファイルアクセスがNFSv4サーバーからである環境での実装の使用が妨げられるため、実装者は文字列をローカルファイルに記録する必要があるアプローチに対して警告されます。

o The string should be different for each server network address that the client accesses, rather than common to all server network addresses. The reason is that it may not be possible for the client to tell if the same server is listening on multiple network addresses. If the client issues SETCLIENTID with the same id string to each network address of such a server, the server will think it is the same client, and each successive SETCLIENTID will cause the server to begin the process of removing the client's previous leased state.

o 文字列は、すべてのサーバーネットワークアドレスに共通するのではなく、クライアントがアクセスするサーバーネットワークアドレスごとに異なる必要があります。その理由は、同じサーバーが複数のネットワークアドレスでリッスンしているかどうかをクライアントが判断できない可能性があるためです。クライアントが同じID文字列のSETCLIENTIDをそのようなサーバーの各ネットワークアドレスに発行すると、サーバーはそれを同じクライアントであると見なし、後続の各SETCLIENTIDによってサーバーはクライアントの以前のリース状態を削除するプロセスを開始します。

o The algorithm for generating the string should not assume that the client's network address won't change. This includes changes between client incarnations and even changes while the client is still running in its current incarnation. This means that if the client includes just the client's and server's network address in the id string, there is a real risk, after the client gives up the network address, that another client, using a similar algorithm for generating the id string, will generate a conflicting id string.


Given the above considerations, an example of a well-generated id string is one that includes:


o The server's network address.

o サーバーのネットワークアドレス。

o The client's network address.

o クライアントのネットワークアドレス。

o For a user-level NFSv4 client, it should contain additional information to distinguish the client from other user-level clients running on the same host, such as a universally unique identifier (UUID).

o ユーザーレベルのNFSv4クライアントの場合、ユニバーサル一意識別子(UUID)など、同じホストで実行されている他のユーザーレベルのクライアントからクライアントを区別するための追加情報が含まれている必要があります。

o Additional information that tends to be unique, such as one or more of:

o 以下の1つ以上など、一意になる傾向がある追加情報。

* The client machine's serial number (for privacy reasons, it is best to perform some one-way function on the serial number).

* クライアントマシンのシリアル番号(プライバシー上の理由から、シリアル番号に対して一方向の機能を実行することをお勧めします)。

* A MAC address (for privacy reasons, it is best to perform some one-way function on the MAC address).

* MACアドレス(プライバシー上の理由から、MACアドレスに対して一方向の機能を実行することをお勧めします)。

* The timestamp of when the NFSv4 software was first installed on the client (though this is subject to the previously mentioned caution about using information that is stored in a file, because the file might only be accessible over NFSv4).

* NFSv4ソフトウェアがクライアントに最初にインストールされたときのタイムスタンプ(ただし、ファイルにはNFSv4経由でしかアクセスできないため、ファイルに格納されている情報の使用に関する前述の注意が必要です)。

* A true random number. However, since this number ought to be the same between client incarnations, this shares the same problem as that of using the timestamp of the software installation.

* 真の乱数。ただし、この数はクライアントのインカネーション間で同じである必要があるため、ソフトウェアインストールのタイムスタンプを使用する場合と同じ問題を共有します。

As a security measure, the server MUST NOT cancel a client's leased state if the principal that established the state for a given id string is not the same as the principal issuing the SETCLIENTID.

セキュリティ対策として、特定のid文字列の状態を確立したプリンシパルがSETCLIENTIDを発行するプリンシパルと同じでない場合、サーバーはクライアントのリース状態をキャンセルしてはなりません(MUST NOT)。

Note that SETCLIENTID (Section 16.33) and SETCLIENTID_CONFIRM (Section 16.34) have a secondary purpose of establishing the information the server needs to make callbacks to the client for the purpose of supporting delegations. It is permitted to change this information via SETCLIENTID and SETCLIENTID_CONFIRM within the same incarnation of the client without removing the client's leased state.

Note that SETCLIENTID (Section 16.33) and SETCLIENTID_CONFIRM (Section 16.34) have a secondary purpose of establishing the information the server needs to make callbacks to the client for the purpose of supporting delegations. It is permitted to change this information via SETCLIENTID and SETCLIENTID_CONFIRM within the same incarnation of the client without removing the client's leased state.

Once a SETCLIENTID and SETCLIENTID_CONFIRM sequence has successfully completed, the client uses the shorthand client identifier, of type clientid4, instead of the longer and less compact nfs_client_id4 structure. This shorthand client identifier (a client ID) is assigned by the server and should be chosen so that it will not conflict with a client ID previously assigned by the server. This applies across server restarts or reboots. When a client ID is presented to a server and that client ID is not recognized, as would happen after a server reboot, the server will reject the request with the error NFS4ERR_STALE_CLIENTID. When this happens, the client must obtain a new client ID by use of the SETCLIENTID operation and then proceed to any other necessary recovery for the server reboot case (see Section 9.6.2).


The client must also employ the SETCLIENTID operation when it receives an NFS4ERR_STALE_STATEID error using a stateid derived from its current client ID, since this also indicates a server reboot, which has invalidated the existing client ID (see Section 9.6.2 for details).


See the detailed descriptions of SETCLIENTID (Section 16.33.4) and SETCLIENTID_CONFIRM (Section 16.34.4) for a complete specification of the operations.

See the detailed descriptions of SETCLIENTID (Section 16.33.4) and SETCLIENTID_CONFIRM (Section 16.34.4) for a complete specification of the operations.

9.1.2. Server Release of Client ID
9.1.2. Server Release of Client ID

If the server determines that the client holds no associated state for its client ID, the server may choose to release the client ID. The server may make this choice for an inactive client so that resources are not consumed by those intermittently active clients. If the client contacts the server after this release, the server must ensure that the client receives the appropriate error so that it will use the SETCLIENTID/SETCLIENTID_CONFIRM sequence to establish a new identity. It should be clear that the server must be very hesitant to release a client ID since the resulting work on the client to recover from such an event will be the same burden as if the server had failed and restarted. Typically, a server would not release a client ID unless there had been no activity from that client for many minutes.

クライアントがそのクライアントIDに関連付けられた状態を保持していないとサーバーが判断した場合、サーバーはクライアントIDを解放することを選択できます。サーバーは、非アクティブなクライアントに対してこの選択を行って、断続的にアクティブなクライアントによってリソースが消費されないようにすることができます。このリリース後にクライアントがサーバーに接続する場合、サーバーは、クライアントが適切なエラーを受信して​​、SETCLIENTID / SETCLIENTID_CONFIRMシーケンスを使用して新しいIDを確立できるようにする必要があります。サーバーがクライアントIDを解放することをためらう必要があることは明らかです。このようなイベントから回復するためのクライアントでの作業は、サーバーに障害が発生して再起動した場合と同じ負担になるためです。通常、サーバーは、そのクライアントから何分間もアクティビティがない場合を除いて、クライアントIDを解放しません。

Note that if the id string in a SETCLIENTID request is properly constructed, and if the client takes care to use the same principal for each successive use of SETCLIENTID, then, barring an active denial-of-service attack, NFS4ERR_CLID_INUSE should never be returned.


However, client bugs, server bugs, or perhaps a deliberate change of the principal owner of the id string (such as the case of a client that changes security flavors, and under the new flavor there is no mapping to the previous owner) will in rare cases result in NFS4ERR_CLID_INUSE.


In that event, when the server gets a SETCLIENTID for a client ID that currently has no state, or it has state but the lease has expired, rather than returning NFS4ERR_CLID_INUSE, the server MUST allow the SETCLIENTID and confirm the new client ID if followed by the appropriate SETCLIENTID_CONFIRM.


9.1.3. Use of Seqids
9.1.3. 配列の使用

In several contexts, 32-bit sequence values called "seqids" are used as part of managing locking state. Such values are used:


o To provide an ordering of locking-related operations associated with a particular lock-owner or open-owner. See Section 9.1.7 for a detailed explanation.

o To provide an ordering of locking-related operations associated with a particular lock-owner or open-owner. See Section 9.1.7 for a detailed explanation.

o To define an ordered set of instances of a set of locks sharing a particular set of ownership characteristics. See Section for a detailed explanation.

o 特定の所有権特性のセットを共有するロックのセットのインスタンスの順序付けられたセットを定義します。詳細な説明については、項を参照してください。

Successive seqid values for the same object are normally arrived at by incrementing the current value by one. This pattern continues until the seqid is incremented past NFS4_UINT32_MAX, in which case one (rather than zero) is to be the next seqid value.


When two seqid values are to be compared to determine which of the two is later, the possibility of wraparound needs to be considered. In many cases, the values are such that simple numeric comparisons can be used. For example, if the seqid values to be compared are both less than one million, the higher value can be considered the later. On the other hand, if one of the values is at or near NFS_UINT32_MAX and the other is less than one million, then implementations can reasonably decide that the lower value has had one more wraparound and is thus, while numerically lower, actually later.


Implementations can compare seqids in the presence of potential wraparound by adopting the reasonable assumption that the chain of increments from one to the other is shorter than 2**31. So, if the difference between the two seqids is less than 2**31, then the lower seqid is to be treated as earlier. If, however, the difference between the two seqids is greater than or equal to 2**31, then it can be assumed that the lower seqid has encountered one more wraparound and can be treated as later.

実装は、1から他への増分のチェーンが2 ** 31よりも短いという合理的な仮定を採用することにより、潜在的なラップアラウンドが存在する場合にseqidを比較できます。したがって、2つのseqidの差が2 ** 31未満の場合、低い方のseqidは以前と同じように処理されます。ただし、2つのseqidの差が2 ** 31以上の場合、下位のseqidがもう1つのラップアラウンドを検出し、後で処理できると見なすことができます。

9.1.4. Stateid Definition
9.1.4. Stateidの定義

When the server grants a lock of any type (including opens, byte-range locks, and delegations), it responds with a unique stateid that represents a set of locks (often a single lock) for the same file, of the same type, and sharing the same ownership characteristics. Thus, opens of the same file by different open-owners each have an identifying stateid. Similarly, each set of byte-range locks on a file owned by a specific lock-owner has its own identifying stateid. Delegations also have associated stateids by which they may be referenced. The stateid is used as a shorthand reference to a lock or set of locks, and given a stateid, the server can determine the associated state-owner or state-owners (in the case of an open-owner/lock-owner pair) and the associated filehandle. When stateids are used, the current filehandle must be the one associated with that stateid.


All stateids associated with a given client ID are associated with a common lease that represents the claim of those stateids and the objects they represent to be maintained by the server. See Section 9.5 for a discussion of the lease.


Each stateid must be unique to the server. Many operations take a stateid as an argument but not a clientid, so the server must be able to infer the client from the stateid.

各stateidはサーバーに固有である必要があります。多くの操作は、stateidを引数として受け取りますが、clientidは受け取りません。そのため、サーバーは、stateidからクライアントを推測できる必要があります。 Stateid Types Stateidタイプ

With the exception of special stateids (see Section, each stateid represents locking objects of one of a set of types defined by the NFSv4 protocol. Note that in all these cases, where we speak of a guarantee, it is understood there are situations such as a client restart, or lock revocation, that allow the guarantee to be voided.


o Stateids may represent opens of files.

o Stateidはファイルのオープンを表す場合があります。

Each stateid in this case represents the OPEN state for a given client ID/open-owner/filehandle triple. Such stateids are subject to change (with consequent incrementing of the stateid's seqid) in response to OPENs that result in upgrade and OPEN_DOWNGRADE operations.

この場合の各stateidは、特定のクライアントID / open-owner / filehandleトリプルのOPEN状態を表します。このような状態IDは、アップグレードとOPEN_DOWNGRADE操作を引き起こすOPENに応じて、変更(状態IDのseqidが増加する)の影響を受けます。

o Stateids may represent sets of byte-range locks.

o Stateidは、一連のバイト範囲ロックを表す場合があります。

All locks held on a particular file by a particular owner and all gotten under the aegis of a particular open file are associated with a single stateid, with the seqid being incremented whenever LOCK and LOCKU operations affect that set of locks.

All locks held on a particular file by a particular owner and all gotten under the aegis of a particular open file are associated with a single stateid, with the seqid being incremented whenever LOCK and LOCKU operations affect that set of locks.

o Stateids may represent file delegations, which are recallable guarantees by the server to the client that other clients will not reference, or will not modify, a particular file until the delegation is returned.

o Stateidはファイルの委任を表す場合があります。これは、委任が返されるまで、特定のファイルを他のクライアントが参照したり変更したりしないことをサーバーがクライアントに保証する保証です。

A stateid represents a single delegation held by a client for a particular filehandle.

stateidは、特定のファイルハンドルに対してクライアントが保持する単一の委任を表します。 Stateid Structure Stateid Structure

Stateids are divided into two fields: a 96-bit "other" field identifying the specific set of locks and a 32-bit "seqid" sequence value. Except in the case of special stateids (see Section, a particular value of the "other" field denotes a set of locks of the same type (for example, byte-range locks, opens, or delegations), for a specific file or directory, and sharing the same ownership characteristics. The seqid designates a specific instance of such a set of locks, and is incremented to indicate changes in such a set of locks, by either the addition or deletion of locks from the set, a change in the byte-range they apply to, or an upgrade or downgrade in the type of one or more locks.

Stateidは、2つのフィールドに分かれています。ロックの特定のセットを識別する96ビットの「その他」フィールドと、32ビットの「seqid」シーケンス値です。特別な状態ID(セクション9.1.4.3を参照)の場合を除き、「other」フィールドの特定の値は、同じタイプのロックのセット(たとえば、バイト範囲ロック、オープン、または委任)を示します。特定のファイルまたはディレクトリ、および同じ所有権特性を共有します。 seqidは、そのようなロックのセットの特定のインスタンスを指定し、セットからのロックの追加または削除、それらが適用されるバイト範囲の変更、またはそのようなロックのセットの変更を示すためにインクリメントされます。 1つ以上のロックのタイプでのアップグレードまたはダウングレード。

When such a set of locks is first created, the server returns a stateid with a seqid value of one. On subsequent operations that modify the set of locks, the server is required to advance the seqid field by one whenever it returns a stateid for the same state-owner/file/type combination and the operation is one that might make some change in the set of locks actually designated. In this case, the server will return a stateid with an "other" field the same as previously used for that state-owner/file/type combination, with an incremented seqid field.

そのようなロックのセットが最初に作成されると、サーバーはseqid値が1のstateidを返します。ロックのセットを変更する後続の操作では、サーバーは、同じ状態所有者/ファイル/タイプの組み合わせのstateidを返し、操作がセットに変更を加える可能性がある操作である場合は常に、seqidフィールドを1つ進める必要があります。実際に指定されたロックの数。この場合、サーバーは、state-owner / file / typeの組み合わせに以前に使用されたものと同じ「other」フィールドを含むstateidを、seqidフィールドを増分して返します。

Seqids will be compared, by both the client and the server. The client uses such comparisons to determine the order of operations, while the server uses them to determine whether the NFS4ERR_OLD_STATEID error is to be returned. In all cases, the possibility of seqid wraparound needs to be taken into account, as discussed in Section 9.1.3.

シーケンスは、クライアントとサーバーの両方で比較されます。クライアントはそのような比較を使用して操作の順序を決定し、サーバーはそれらを使用してNFS4ERR_OLD_STATEIDエラーが返されるかどうかを決定します。セクション9.1.3で説明したように、すべての場合において、seqidラップアラウンドの可能性を考慮する必要があります。 Special Stateids 特別国家

Stateid values whose "other" field is either all zeros or all ones are reserved. They MUST NOT be assigned by the server but have special meanings defined by the protocol. The particular meaning depends on whether the "other" field is all zeros or all ones and the specific value of the seqid field.

Stateid values whose "other" field is either all zeros or all ones are reserved. They MUST NOT be assigned by the server but have special meanings defined by the protocol. The particular meaning depends on whether the "other" field is all zeros or all ones and the specific value of the seqid field.

The following combinations of "other" and seqid are defined in NFSv4:


Anonymous Stateid: When "other" and seqid are both zero, the stateid is treated as a special anonymous stateid, which can be used in READ, WRITE, and SETATTR requests to indicate the absence of any open state associated with the request. When an anonymous stateid value is used, and an existing open denies the form of access requested, then access will be denied to the request.


READ Bypass Stateid: When "other" and seqid are both all ones, the stateid is a special READ bypass stateid. When this value is used in WRITE or SETATTR, it is treated like the anonymous value. When used in READ, the server MAY grant access, even if access would normally be denied to READ requests.

READバイパス状態ID:「other」とseqidが両方とも1の場合、stateidは特別なREADバイパス状態IDです。この値をWRITEまたはSETATTRで使用すると、匿名値のように扱われます。 READで使用すると、通常はREAD要求へのアクセスが拒否される場合でも、サーバーはアクセスを許可できます(MAY)。

If a stateid value is used that has all zeros or all ones in the "other" field but does not match one of the cases above, the server MUST return the error NFS4ERR_BAD_STATEID.

If a stateid value is used that has all zeros or all ones in the "other" field but does not match one of the cases above, the server MUST return the error NFS4ERR_BAD_STATEID.

Special stateids, unlike other stateids, are not associated with individual client IDs or filehandles and can be used with all valid client IDs and filehandles.

他の状態IDとは異なり、特別な状態IDは個々のクライアントIDまたはファイルハンドルに関連付けられておらず、すべての有効なクライアントIDおよびファイルハンドルで使用できます。 Stateid Lifetime and Validation Stateidのライフタイムと検証

Stateids must remain valid until either a client restart or a server restart, or until the client returns all of the locks associated with the stateid by means of an operation such as CLOSE or DELEGRETURN. If the locks are lost due to revocation, as long as the client ID is valid, the stateid remains a valid designation of that revoked state. Stateids associated with byte-range locks are an exception. They remain valid even if a LOCKU frees all remaining locks, so long as the open file with which they are associated remains open.


It should be noted that there are situations in which the client's locks become invalid, without the client requesting they be returned. These include lease expiration and a number of forms of lock revocation within the lease period. It is important to note that in these situations, the stateid remains valid and the client can use it to determine the disposition of the associated lost locks.


An "other" value must never be reused for a different purpose (i.e., different filehandle, owner, or type of locks) within the context of a single client ID. A server may retain the "other" value for the same purpose beyond the point where it may otherwise be freed, but if it does so, it must maintain seqid continuity with previous values.


One mechanism that may be used to satisfy the requirement that the server recognize invalid and out-of-date stateids is for the server to divide the "other" field of the stateid into two fields:


o An index into a table of locking-state structures.

o ロック状態構造のテーブルへのインデックス。

o A generation number that is incremented on each allocation of a table entry for a particular use.

o 特定の用途のためのテーブルエントリの割り当てごとに増分される世代番号。

And then store the following in each table entry:


o The client ID with which the stateid is associated.

o stateidが関連付けられているクライアントID。

o The current generation number for the (at most one) valid stateid sharing this index value.

o このインデックス値を共有する(最大で1つの)有効な状態IDの現在の世代番号。

o The filehandle of the file on which the locks are taken.

o ロックが行われるファイルのファイルハンドル。

o An indication of the type of stateid (open, byte-range lock, file delegation).

o An indication of the type of stateid (open, byte-range lock, file delegation).

o The last seqid value returned corresponding to the current "other" value.

o 現在の「その他」の値に対応して返された最後のseqid値。

o An indication of the current status of the locks associated with this stateid -- in particular, whether these have been revoked and, if so, for what reason.

o このstateidに関連付けられているロックの現在のステータスの表示-特に、これらが取り消されたかどうか、取り消されている場合は、その理由を示します。

With this information, an incoming stateid can be validated and the appropriate error returned when necessary. Special and non-special stateids are handled separately. (See Section for a discussion of special stateids.)

With this information, an incoming stateid can be validated and the appropriate error returned when necessary. Special and non-special stateids are handled separately. (See Section for a discussion of special stateids.)

When a stateid is being tested, and the "other" field is all zeros or all ones, a check that the "other" and seqid fields match a defined combination for a special stateid is done and the results determined as follows:

When a stateid is being tested, and the "other" field is all zeros or all ones, a check that the "other" and seqid fields match a defined combination for a special stateid is done and the results determined as follows:

o If the "other" and seqid fields do not match a defined combination associated with a special stateid, the error NFS4ERR_BAD_STATEID is returned.

o 「その他」およびseqidフィールドが、特別な状態IDに関連付けられた定義済みの組み合わせと一致しない場合、エラーNFS4ERR_BAD_STATEIDが返されます。

o If the combination is valid in general but is not appropriate to the context in which the stateid is used (e.g., an all-zero stateid is used when an open stateid is required in a LOCK operation), the error NFS4ERR_BAD_STATEID is also returned.

o 組み合わせは一般的には有効ですが、stateidが使用されるコンテキストに適さない場合(たとえば、LOCK操作でopen stateidが必要なときにすべてゼロのstateidが使用される場合)、エラーNFS4ERR_BAD_STATEIDも返されます。

o Otherwise, the check is completed and the special stateid is accepted as valid.

o それ以外の場合、チェックは完了し、特別な状態IDが有効として受け入れられます。

When a stateid is being tested, and the "other" field is neither all zeros nor all ones, the following procedure could be used to validate an incoming stateid and return an appropriate error, when necessary, assuming that the "other" field would be divided into a table index and an entry generation. Note that the terms "earlier" and "later" used in connection with seqid comparison are to be understood as explained in Section 9.1.3.

状態IDがテストされており、「その他」フィールドがすべて0でもすべて1でもない場合、次の手順を使用して、受信した状態IDを検証し、必要に応じて「その他」フィールドがテーブルインデックスとエントリ生成に分かれています。 seqidの比較に関連して使用される「以前」および「後で」という用語は、セクション9.1.3で説明されているように理解されることに注意してください。

o If the table index field is outside the range of the associated table, return NFS4ERR_BAD_STATEID.

o テーブルインデックスフィールドが関連するテーブルの範囲外の場合は、NFS4ERR_BAD_STATEIDを返します。

o If the selected table entry is of a different generation than that specified in the incoming stateid, return NFS4ERR_BAD_STATEID.

o 選択されたテーブルエントリが、受信状態IDで指定された世代とは異なる世代である場合は、NFS4ERR_BAD_STATEIDを返します。

o If the selected table entry does not match the current filehandle, return NFS4ERR_BAD_STATEID.

o 選択したテーブルエントリが現在のファイルハンドルと一致しない場合は、NFS4ERR_BAD_STATEIDを返します。

o If the stateid represents revoked state or state lost as a result of lease expiration, then return NFS4ERR_EXPIRED, NFS4ERR_BAD_STATEID, or NFS4ERR_ADMIN_REVOKED, as appropriate.

o 状態IDが、取り消された状態またはリースの期限切れの結果として失われた状態を表す場合、NFS4ERR_EXPIRED、NFS4ERR_BAD_STATEID、またはNFS4ERR_ADMIN_REVOKEDを適宜返します。

o If the stateid type is not valid for the context in which the stateid appears, return NFS4ERR_BAD_STATEID. Note that a stateid may be valid in general but invalid for a particular operation, as, for example, when a stateid that doesn't represent byte-range locks is passed to the non-from_open case of LOCK or to LOCKU, or when a stateid that does not represent an open is passed to CLOSE or OPEN_DOWNGRADE. In such cases, the server MUST return NFS4ERR_BAD_STATEID.

o 状態IDが表示されるコンテキストに対して状態IDのタイプが有効でない場合は、NFS4ERR_BAD_STATEIDを返します。たとえば、バイト範囲のロックを表さない状態IDがLOCKのnon-from_openケースまたはLOCKUに渡されたとき、またはオープンを表していない状態IDは、CLOSEまたはOPEN_DOWNGRADEに渡されます。このような場合、サーバーはNFS4ERR_BAD_STATEIDを返す必要があります。

o If the seqid field is not zero and it is later than the current sequence value corresponding to the current "other" field, return NFS4ERR_BAD_STATEID.

o seqidフィールドがゼロではなく、現在の「その他」フィールドに対応する現在のシーケンス値よりも遅い場合は、NFS4ERR_BAD_STATEIDを返します。

o If the seqid field is earlier than the current sequence value corresponding to the current "other" field, return NFS4ERR_OLD_STATEID.

o seqidフィールドが現在の「その他」フィールドに対応する現在のシーケンス値よりも古い場合は、NFS4ERR_OLD_STATEIDを返します。

o Otherwise, the stateid is valid, and the table entry should contain any additional information about the type of stateid and information associated with that particular type of stateid, such as the associated set of locks (e.g., open-owner and lock-owner information), as well as information on the specific locks themselves, such as open modes and byte ranges.

o それ以外の場合、stateidは有効であり、テーブルエントリには、stateidのタイプに関する追加情報と、関連するロックのセットなどの特定のタイプのstateidに関連付けられた情報(たとえば、open-ownerおよびlock-owner情報)が含まれている必要があります。 、およびオープンモードやバイト範囲などの特定のロック自体に関する情報。 Stateid Use for I/O Operations I / O操作のステートイド使用

Clients performing Input/Output (I/O) operations need to select an appropriate stateid based on the locks (including opens and delegations) held by the client and the various types of state-owners sending the I/O requests. SETATTR operations that change the file size are treated like I/O operations in this regard.

入出力(I / O)操作を実行するクライアントは、クライアントが保持しているロック(オープンと委任を含む)およびI / O要求を送信するさまざまなタイプの状態所有者に基づいて、適切な状態IDを選択する必要があります。ファイルサイズを変更するSETATTR操作は、この点でI / O操作と同様に扱われます。

The following rules, applied in order of decreasing priority, govern the selection of the appropriate stateid. In following these rules, the client will only consider locks of which it has actually received notification by an appropriate operation response or callback.


o If the client holds a delegation for the file in question, the delegation stateid SHOULD be used.

o クライアントが問題のファイルの委任を保持している場合は、委任のstateidを使用する必要があります(SHOULD)。

o Otherwise, if the entity corresponding to the lock-owner (e.g., a process) sending the I/O has a byte-range lock stateid for the associated open file, then the byte-range lock stateid for that lock-owner and open file SHOULD be used.

o それ以外の場合、I / Oを送信するロック所有者(たとえば、プロセス)に対応するエンティティに、関連付けられたオープンファイルのバイト範囲ロック状態IDがある場合、そのロック所有者とオープンファイルのバイト範囲ロック状態ID使用すべきです。

o If there is no byte-range lock stateid, then the OPEN stateid for the current open-owner, i.e., the OPEN stateid for the open file in question, SHOULD be used.

o バイト範囲のロック状態IDがない場合は、現在のオープン所有者のOPEN状態ID、つまり問題のオープンファイルのOPEN状態IDを使用する必要があります(SHOULD)。

o Finally, if none of the above apply, then a special stateid SHOULD be used.

o 最後に、上記のいずれにも該当しない場合は、特別な状態IDを使用する必要があります(SHOULD)。

Ignoring these rules may result in situations in which the server does not have information necessary to properly process the request. For example, when mandatory byte-range locks are in effect, if the stateid does not indicate the proper lock-owner, via a lock stateid, a request might be avoidably rejected.


The server, however, should not try to enforce these ordering rules and should use whatever information is available to properly process I/O requests. In particular, when a client has a delegation for a given file, it SHOULD take note of this fact in processing a request, even if it is sent with a special stateid.

The server, however, should not try to enforce these ordering rules and should use whatever information is available to properly process I/O requests. In particular, when a client has a delegation for a given file, it SHOULD take note of this fact in processing a request, even if it is sent with a special stateid. Stateid Use for SETATTR Operations Stateid Use for SETATTR Operations

In the case of SETATTR operations, a stateid is present. In cases other than those that set the file size, the client may send either a special stateid or, when a delegation is held for the file in question, a delegation stateid. While the server SHOULD validate the stateid and may use the stateid to optimize the determination as to whether a delegation is held, it SHOULD note the presence of a delegation even when a special stateid is sent, and MUST accept a valid delegation stateid when sent.


9.1.5. Lock-Owner
9.1.5. ロック所有者

When requesting a lock, the client must present to the server the client ID and an identifier for the owner of the requested lock. These two fields comprise the lock-owner and are defined as follows:

When requesting a lock, the client must present to the server the client ID and an identifier for the owner of the requested lock. These two fields comprise the lock-owner and are defined as follows:

o A client ID returned by the server as part of the client's use of the SETCLIENTID operation.

o クライアントによるSETCLIENTID操作の使用の一部としてサーバーから返されたクライアントID。

o A variable-length opaque array used to uniquely define the owner of a lock managed by the client.

o クライアントが管理するロックの所有者を一意に定義するために使用される可変長の不透明な配列。

This may be a thread id, process id, or other unique value.


When the server grants the lock, it responds with a unique stateid. The stateid is used as a shorthand reference to the lock-owner, since the server will be maintaining the correspondence between them.


9.1.6. Use of the Stateid and Locking
9.1.6. Stateidとロックの使用

All READ, WRITE, and SETATTR operations contain a stateid. For the purposes of this section, SETATTR operations that change the size attribute of a file are treated as if they are writing the area between the old and new size (i.e., the range truncated or added to the file by means of the SETATTR), even where SETATTR is not explicitly mentioned in the text. The stateid passed to one of these operations must be one that represents an OPEN (e.g., via the open-owner), a set of byte-range locks, or a delegation, or it may be a special stateid representing anonymous access or the READ bypass stateid.

すべてのREAD、WRITE、およびSETATTR操作には、stateidが含まれます。このセクションの目的のために、ファイルのサイズ属性を変更するSETATTR操作は、古いサイズと新しいサイズの間の領域(つまり、SETATTRによって切り捨てられた、またはファイルに追加された範囲)を書き込むかのように扱われます。 SETATTRがテキストで明示的に言及されていない場合でも。これらの操作の1つに渡される状態IDは、OPEN(たとえば、open-ownerを介して)、一連のバイト範囲ロック、または委任を表すものであるか、匿名アクセスまたはREADを表す特別な状態IDである可能性があります。ステートIDをバイパスします。

If the state-owner performs a READ or WRITE in a situation in which it has established a lock or share reservation on the server (any OPEN constitutes a share reservation), the stateid (previously returned by the server) must be used to indicate what locks, including both byte-range locks and share reservations, are held by the state-owner. If no state is established by the client -- either byte-range lock or share reservation -- the anonymous stateid is used. Regardless of whether an anonymous stateid or a stateid returned by the server is used, if there is a conflicting share reservation or mandatory byte-range lock held on the file, the server MUST refuse to service the READ or WRITE operation.


Share reservations are established by OPEN operations and by their nature are mandatory in that when the OPEN denies READ or WRITE operations, that denial results in such operations being rejected with error NFS4ERR_LOCKED. Byte-range locks may be implemented by the server as either mandatory or advisory, or the choice of mandatory or advisory behavior may be determined by the server on the basis of the file being accessed (for example, some UNIX-based servers support a "mandatory lock bit" on the mode attribute such that if set, byte-range locks are required on the file before I/O is possible). When byte-range locks are advisory, they only prevent the granting of conflicting lock requests and have no effect on READs or WRITEs. Mandatory byte-range locks, however, prevent conflicting I/O operations. When they are attempted, they are rejected with NFS4ERR_LOCKED. When the client gets NFS4ERR_LOCKED on a file it knows it has the proper share reservation for, it will need to issue a LOCK request on the region of the file that includes the region the I/O was to be performed on, with an appropriate locktype (i.e., READ*_LT for a READ operation, WRITE*_LT for a WRITE operation).

共有の予約はOPEN操作によって確立されます。OPEN予約がREADまたはWRITE操作を拒否すると、そのような操作はエラーNFS4ERR_LOCKEDで拒否されます。バイト範囲ロックは、必須または助言としてサーバーによって実装される場合があります。または、必須または助言の動作の選択は、アクセスされるファイルに基づいてサーバーによって決定される場合があります(たとえば、一部のUNIXベースのサーバーは「必須のロックビット」が設定されている場合は、I / Oが可能になる前にファイルにバイト範囲のロックが必要になります。バイト範囲ロックが助言である場合、それらは競合するロック要求の許可を防ぐだけで、READまたはWRITEには影響を与えません。ただし、必須のバイト範囲ロックは、I / O操作の競合を防ぎます。試行された場合、NFS4ERR_LOCKEDで拒否されます。クライアントは、適切な共有予約があることを知っているファイルでNFS4ERR_LOCKEDを取得すると、適切なロックタイプを使用して、I / Oが実行される領域を含むファイルの領域でLOCK要求を発行する必要があります。 (つまり、READ操作の場合はREAD * _LT、WRITE操作の場合はWRITE * _LT)。

With NFSv3, there was no notion of a stateid, so there was no way to tell if the application process of the client sending the READ or WRITE operation had also acquired the appropriate byte-range lock on the file. Thus, there was no way to implement mandatory locking. With the stateid construct, this barrier has been removed.

NFSv3では、stateidの概念がなかったため、READまたはWRITE操作を送信するクライアントのアプリケーションプロセスがファイルの適切なバイト範囲ロックも取得したかどうかを判断する方法がありませんでした。したがって、強制ロックを実装する方法はありませんでした。 stateidコンストラクトにより、この障壁が取り除かれました。

Note that for UNIX environments that support mandatory file locking, the distinction between advisory and mandatory locking is subtle. In fact, advisory and mandatory byte-range locks are exactly the same insofar as the APIs and requirements on implementation are concerned. If the mandatory lock attribute is set on the file, the server checks to see if the lock-owner has an appropriate shared (read) or exclusive (write) byte-range lock on the region it wishes to read or write to. If there is no appropriate lock, the server checks if there is a conflicting lock (which can be done by attempting to acquire the conflicting lock on behalf of the lock-owner and, if successful, release the lock after the READ or WRITE is done), and if there is, the server returns NFS4ERR_LOCKED.

Note that for UNIX environments that support mandatory file locking, the distinction between advisory and mandatory locking is subtle. In fact, advisory and mandatory byte-range locks are exactly the same insofar as the APIs and requirements on implementation are concerned. If the mandatory lock attribute is set on the file, the server checks to see if the lock-owner has an appropriate shared (read) or exclusive (write) byte-range lock on the region it wishes to read or write to. If there is no appropriate lock, the server checks if there is a conflicting lock (which can be done by attempting to acquire the conflicting lock on behalf of the lock-owner and, if successful, release the lock after the READ or WRITE is done), and if there is, the server returns NFS4ERR_LOCKED.

For Windows environments, there are no advisory byte-range locks, so the server always checks for byte-range locks during I/O requests.

Windows環境の場合、勧告的なバイト範囲ロックはないため、サーバーはI / O要求時に常にバイト範囲ロックをチェックします。

Thus, the NFSv4 LOCK operation does not need to distinguish between advisory and mandatory byte-range locks. It is the NFSv4 server's processing of the READ and WRITE operations that introduces the distinction.

したがって、NFSv4 LOCK操作は、勧告的ロックと必須バイト範囲ロックを区別する必要はありません。区別を導入するのは、NFSv4サーバーのREADおよびWRITE操作の処理です。

Every stateid other than the special stateid values noted in this section, whether returned by an OPEN-type operation (i.e., OPEN, OPEN_DOWNGRADE) or by a LOCK-type operation (i.e., LOCK or LOCKU), defines an access mode for the file (i.e., READ, WRITE, or READ-WRITE) as established by the original OPEN that began the stateid sequence, and as modified by subsequent OPENs and OPEN_DOWNGRADEs within that stateid sequence. When a READ, WRITE, or SETATTR that specifies the size attribute is done, the operation is subject to checking against the access mode to verify that the operation is appropriate given the OPEN with which the operation is associated.


In the case of WRITE-type operations (i.e., WRITEs and SETATTRs that set size), the server must verify that the access mode allows writing and return an NFS4ERR_OPENMODE error if it does not. In the case of READ, the server may perform the corresponding check on the access mode, or it may choose to allow READ on opens for WRITE only, to accommodate clients whose write implementation may unavoidably do reads (e.g., due to buffer cache constraints). However, even if READs are allowed in these circumstances, the server MUST still check for locks that conflict with the READ (e.g., another open specifying denial of READs). Note that a server that does enforce the access mode check on READs need not explicitly check for conflicting share reservations since the existence of OPEN for read access guarantees that no conflicting share reservation can exist.

WRITEタイプの操作(つまり、サイズを設定するWRITEおよびSETATTR)の場合、サーバーはアクセスモードが書き込みを許可していることを確認し、許可していない場合はNFS4ERR_OPENMODEエラーを返す必要があります。 READの場合、サーバーはアクセスモードで対応するチェックを実行するか、書き込みの実装が読み取りを不可避的に行う可能性のあるクライアント(バッファキャッシュの制約など)に対応するために、オープン時にREADをWRITEのみに許可することを選択できます。 。ただし、これらの状況でREADが許可されている場合でも、サーバーはREADと競合するロックを確認する必要があります(たとえば、READの拒否を指定する別のオープン)。読み取りアクセスにOPENが存在すると、競合する共有予約が存在しないことが保証されるため、READでアクセスモードチェックを実行するサーバーは、競合する共有予約を明示的にチェックする必要がないことに注意してください。

A READ bypass stateid MAY allow READ operations to bypass locking checks at the server. However, WRITE operations with a READ bypass stateid MUST NOT bypass locking checks and are treated exactly the same as if an anonymous stateid were used.

READバイパス状態IDは、READ操作がサーバーでのロックチェックをバイパスすることを許可する場合があります。ただし、READバイパス状態IDを使用した書き込み操作は、ロックチェックをバイパスしてはならず(MUST NOT)、匿名の状態IDが使用された場合とまったく同じように扱われます。

A lock may not be granted while a READ or WRITE operation using one of the special stateids is being performed and the range of the lock request conflicts with the range of the READ or WRITE operation. For the purposes of this paragraph, a conflict occurs when a shared lock is requested and a WRITE operation is being performed, or an exclusive lock is requested and either a READ or a WRITE operation is being performed. A SETATTR that sets size is treated similarly to a WRITE as discussed above.


9.1.7. Sequencing of Lock Requests
9.1.7. ロック要求の順序付け

Locking is different than most NFS operations as it requires "at-most-one" semantics that are not provided by ONC RPC. ONC RPC over a reliable transport is not sufficient because a sequence of locking requests may span multiple TCP connections. In the face of retransmission or reordering, lock or unlock requests must have a well-defined and consistent behavior. To accomplish this, each lock request contains a sequence number that is a consecutively increasing integer. Different state-owners have different sequences. The server maintains the last sequence number (L) received and the response that was returned. The server SHOULD assign a seqid value of one for the first request issued for any given state-owner. Subsequent values are arrived at by incrementing the seqid value, subject to wraparound as described in Section 9.1.3.

ロックは、ONC RPCによって提供されない「最大1つ」のセマンティクスを必要とするため、ほとんどのNFS操作とは異なります。一連のロック要求が複数のTCP接続にまたがることがあるため、信頼性の高いトランスポートを介したONC RPCでは不十分です。再送信または並べ替えに直面して、ロックまたはロック解除要求は、明確に定義された一貫した動作を持つ必要があります。これを実現するために、各ロック要求には、連続的に増加する整数であるシーケンス番号が含まれています。国の所有者が異なれば、シーケンスも異なります。サーバーは、最後に受信したシーケンス番号(L)と返された応答を保持します。サーバーは、任意の状態所有者に対して発行された最初の要求に1のseqid値を割り当てる必要があります。後続の値は、セクション9.1.3で説明されているようにラップアラウンドに従って、seqid値を増分することによって到達します。

Note that for requests that contain a sequence number, for each state-owner, there should be no more than one outstanding request.


When a request is received, its sequence number (r) is compared to that of the last one received (L). Only if it has the correct next sequence, normally L + 1, is the request processed beyond the point of seqid checking. Given a properly functioning client, the response to (r) must have been received before the last request (L) was sent. If a duplicate of last request (r == L) is received, the stored response is returned. If the sequence value received is any other value, it is rejected with the return of error NFS4ERR_BAD_SEQID. Sequence history is reinitialized whenever the SETCLIENTID/ SETCLIENTID_CONFIRM sequence changes the client verifier.

要求を受信すると、そのシーケンス番号(r)が最後に受信したもの(L)と比較されます。正しい次のシーケンス(通常はL + 1)がある場合のみ、リクエストはseqidチェックのポイントを超えて処理されます。クライアントが適切に機能している場合、(r)への応答は、最後の要求(L)が送信される前に受信されている必要があります。最後のリクエストの重複(r == L)が受信されると、保存されているレスポンスが返されます。受け取ったシーケンス値が他の値の場合、エラーNFS4ERR_BAD_SEQIDが返されて拒否されます。 SETCLIENTID / SETCLIENTID_CONFIRMシーケンスがクライアントベリファイアを変更するたびに、シーケンス履歴が再初期化されます。

It is critical that the server maintain the last response sent to the client to provide a more reliable cache of duplicate non-idempotent requests than that of the traditional cache described in [Chet]. The traditional duplicate request cache uses a least recently used algorithm for removing unneeded requests. However, the last lock request and response on a given state-owner must be cached as long as the lock state exists on the server.


The client MUST advance the sequence number for the CLOSE, LOCK, LOCKU, OPEN, OPEN_CONFIRM, and OPEN_DOWNGRADE operations. This is true even in the event that the previous operation that used the sequence number received an error. The only exception to this rule is if the previous operation received one of the following errors: NFS4ERR_STALE_CLIENTID, NFS4ERR_STALE_STATEID, NFS4ERR_BAD_STATEID, NFS4ERR_BAD_SEQID, NFS4ERR_BADXDR, NFS4ERR_RESOURCE, NFS4ERR_NOFILEHANDLE, or NFS4ERR_MOVED.


9.1.8. Recovery from Replayed Requests
9.1.8. リプレイされたリクエストからの回復

As described above, the sequence number is per state-owner. As long as the server maintains the last sequence number received and follows the methods described above, there are no risks of a Byzantine router re-sending old requests. The server need only maintain the (state-owner, sequence number) state as long as there are open files or closed files with locks outstanding.


LOCK, LOCKU, OPEN, OPEN_DOWNGRADE, and CLOSE each contain a sequence number, and therefore the risk of the replay of these operations resulting in undesired effects is non-existent while the server maintains the state-owner state.


9.1.9. Interactions of Multiple Sequence Values
9.1.9. 複数のシーケンス値の相互作用

Some operations may have multiple sources of data for request sequence checking and retransmission determination. Some operations have multiple sequence values associated with multiple types of state-owners. In addition, such operations may also have a stateid with its own seqid value, that will be checked for validity.


As noted above, there may be multiple sequence values to check. The following rules should be followed by the server in processing these multiple sequence values within a single operation.


o When a sequence value associated with a state-owner is unavailable for checking because the state-owner is unknown to the server, it takes no part in the comparison.

o When a sequence value associated with a state-owner is unavailable for checking because the state-owner is unknown to the server, it takes no part in the comparison.

o When any of the state-owner sequence values are invalid, NFS4ERR_BAD_SEQID is returned. When a stateid sequence is checked, NFS4ERR_BAD_STATEID or NFS4ERR_OLD_STATEID is returned as appropriate, but NFS4ERR_BAD_SEQID has priority.

o 状態所有者のシーケンス値のいずれかが無効な場合、NFS4ERR_BAD_SEQIDが返されます。 stateidシーケンスがチェックされると、NFS4ERR_BAD_STATEIDまたはNFS4ERR_OLD_STATEIDが適切に返されますが、NFS4ERR_BAD_SEQIDが優先されます。

o When any one of the sequence values matches a previous request, for a state-owner, it is treated as a retransmission and not re-executed. When the type of the operation does not match that originally used, NFS4ERR_BAD_SEQID is returned. When the server can determine that the request differs from the original, it may return NFS4ERR_BAD_SEQID.

o シーケンス値のいずれかが前の要求と一致する場合、状態所有者の場合、それは再送信として扱われ、再実行されません。操作のタイプが最初に使用されたものと一致しない場合、NFS4ERR_BAD_SEQIDが返されます。サーバーが要求が元の要求と異なると判断できる場合、サーバーはNFS4ERR_BAD_SEQIDを返すことがあります。

o When multiple sequence values match previous operations but the operations are not the same, NFS4ERR_BAD_SEQID is returned.

o 複数のシーケンス値が前の操作と一致するが、操作が同じでない場合、NFS4ERR_BAD_SEQIDが返されます。

o When there are no sequence values available for comparison and the operation is an OPEN, the server indicates to the client that an OPEN_CONFIRM is required, unless it can conclusively determine that confirmation is not required (e.g., by knowing that no open-owner state has ever been released for the current clientid).

o 比較に使用できるシーケンス値がなく、操作がOPENの場合、サーバーはクライアントにOPEN_CONFIRMが必要であることをクライアントに示します。現在のclientid用にリリースされています)。

9.1.10. Releasing State-Owner State
9.1.10. 状態所有者状態の解放

When a particular state-owner no longer holds open or file locking state at the server, the server may choose to release the sequence number state associated with the state-owner. The server may make this choice based on lease expiration, the reclamation of server memory, or other implementation-specific details. Note that when this is done, a retransmitted request, normally identified by a matching state-owner sequence, may not be correctly recognized, so that the client will not receive the original response that it would have if the state-owner state was not released.


If the server were able to be sure that a given state-owner would never again be used by a client, such an issue could not arise. Even when the state-owner state is released and the client subsequently uses that state-owner, retransmitted requests will be detected as invalid and the request not executed, although the client may have a recovery path that is more complicated than simply getting the original response back transparently.


In any event, the server is able to safely release state-owner state (in the sense that retransmitted requests will not be erroneously acted upon) when the state-owner is not currently being utilized by the client (i.e., there are no open files associated with an open-owner and no lock stateids associated with a lock-owner). The server may choose to hold the state-owner state in order to simplify the recovery path, in the case in which retransmissions of currently active requests are received. However, the period for which it chooses to hold this state is implementation specific.


In the case that a LOCK, LOCKU, OPEN_DOWNGRADE, or CLOSE is retransmitted after the server has previously released the state-owner state, the server will find that the state-owner has no files open and an error will be returned to the client. If the state-owner does have a file open, the stateid will not match and again an error is returned to the client.


9.1.11. Use of Open Confirmation
9.1.11. オープン確認の使用

In the case that an OPEN is retransmitted and the open-owner is being used for the first time or the open-owner state has been previously released by the server, the use of the OPEN_CONFIRM operation will prevent incorrect behavior. When the server observes the use of the open-owner for the first time, it will direct the client to perform the OPEN_CONFIRM for the corresponding OPEN. This sequence establishes the use of an open-owner and associated sequence number. Since the OPEN_CONFIRM sequence connects a new open-owner on the server with an existing open-owner on a client, the sequence number may have any valid (i.e., non-zero) value. The OPEN_CONFIRM step assures the server that the value received is the correct one. (See Section 16.18 for further details.)

OPENが再送信され、open-ownerが初めて使用される場合、またはopen-owner状態がサーバーによって以前に解放されている場合、OPEN_CONFIRM操作を使用すると、不正な動作を防ぐことができます。サーバーは、open-ownerの使用を初めて確認するときに、対応するOPENに対してOPEN_CONFIRMを実行するようにクライアントに指示します。このシーケンスは、オープンオーナーと関連するシーケンス番号の使用を確立します。 OPEN_CONFIRMシーケンスは、サーバー上の新しいオープンオーナーをクライアント上の既存のオープンオーナーに接続するため、シーケンス番号には有効な(つまり、ゼロ以外の)値が含まれる場合があります。 OPEN_CONFIRMステップは、受け取った値が正しいものであることをサーバーに保証します。 (詳細については、セクション16.18を参照してください。)

There are a number of situations in which the requirement to confirm an OPEN would pose difficulties for the client and server, in that they would be prevented from acting in a timely fashion on information received, because that information would be provisional, subject to deletion upon non-confirmation. Fortunately, these are situations in which the server can avoid the need for confirmation when responding to open requests. The two constraints are:

OPENを確認する要件がクライアントとサーバーに困難をもたらす多くの状況があります。それらの情報は暫定的なものであり、削除される可能性があるため、受信した情報に対してタイムリーに機能することが妨げられます。未確認。幸いなことに、これらは、サーバーがオープン要求に応答するときに確認の必要を回避できる状況です。 2つの制約は次のとおりです。

o The server must not bestow a delegation for any open that would require confirmation.

o サーバーは、確認を必要とするオープンに対して委任を与えてはなりません。

o The server MUST NOT require confirmation on a reclaim-type open (i.e., one specifying claim type CLAIM_PREVIOUS or CLAIM_DELEGATE_PREV).

o サーバーは、再利用タイプのオープン(つまり、クレームタイプCLAIM_PREVIOUSまたはCLAIM_DELEGATE_PREVを指定するもの)の確認を要求してはなりません(MUST NOT)。

These constraints are related in that reclaim-type opens are the only ones in which the server may be required to send a delegation. For CLAIM_NULL, sending the delegation is optional, while for CLAIM_DELEGATE_CUR, no delegation is sent.

これらの制約は、サーバーが委任を送信する必要がある場合があるのは、再利用タイプのオープンだけであるという点で関連しています。 CLAIM_NULLの場合、委任の送信はオプションですが、CLAIM_DELEGATE_CURの場合、委任は送信されません。

Delegations being sent with an open requiring confirmation are troublesome because recovering from non-confirmation adds undue complexity to the protocol, while requiring confirmation on reclaim-type opens poses difficulties in that the inability to resolve the status of the reclaim until lease expiration may make it difficult to have timely determination of the set of locks being reclaimed (since the grace period may expire).

確認を必要とするオープンで送信される委任は、非確認から回復するとプロトコルが過度に複雑になるので厄介ですが、再利用タイプのオープンで確認を要求すると、リースの期限が切れるまで再利用のステータスを解決できないために困難になる場合があります。 (猶予期間が期限切れになる可能性があるため)再利用されるロックのセットをタイムリーに決定することが困難です。

Requiring open confirmation on reclaim-type opens is avoidable because of the nature of the environments in which such opens are done. For CLAIM_PREVIOUS opens, this is immediately after server reboot, so there should be no time for open-owners to be created, found to be unused, and recycled. For CLAIM_DELEGATE_PREV opens, we are dealing with either a client reboot situation or a network partition resulting in deletion of lease state (and returning NFS4ERR_EXPIRED). A server that supports delegations can be sure that no open-owners for that client have been recycled since client initialization or deletion of lease state and thus can be confident that confirmation will not be required.

このようなオープンが行われる環境の性質上、再利用タイプのオープンでオープン確認を要求することは避けられます。 CLAIM_PREVIOUSオープンの場合、これはサーバーの再起動直後なので、オープンオーナーが作成され、未使用であることが判明し、リサイクルされる時間はありません。 CLAIM_DELEGATE_PREVオープンの場合、クライアントの再起動状況またはネットワークパーティションのいずれかを処理しており、リース状態が削除されます(NFS4ERR_EXPIREDが返されます)。委任をサポートするサーバーは、クライアントの初期化またはリース状態の削除以降、そのクライアントのオープンオーナーがリサイクルされていないことを確認できるため、確認が不要であることを確信できます。

9.2. Lock Ranges
9.2. ロック範囲

The protocol allows a lock-owner to request a lock with a byte range and then either upgrade or unlock a sub-range of the initial lock. It is expected that this will be an uncommon type of request. In any case, servers or server file systems may not be able to support sub-range lock semantics. In the event that a server receives a locking request that represents a sub-range of current locking state for the lock-owner, the server is allowed to return the error NFS4ERR_LOCK_RANGE to signify that it does not support sub-range lock operations. Therefore, the client should be prepared to receive this error and, if appropriate, report the error to the requesting application.

The protocol allows a lock-owner to request a lock with a byte range and then either upgrade or unlock a sub-range of the initial lock. It is expected that this will be an uncommon type of request. In any case, servers or server file systems may not be able to support sub-range lock semantics. In the event that a server receives a locking request that represents a sub-range of current locking state for the lock-owner, the server is allowed to return the error NFS4ERR_LOCK_RANGE to signify that it does not support sub-range lock operations. Therefore, the client should be prepared to receive this error and, if appropriate, report the error to the requesting application.

The client is discouraged from combining multiple independent locking ranges that happen to be adjacent into a single request, since the server may not support sub-range requests, and for reasons related to the recovery of file locking state in the event of server failure. As discussed in Section 9.6.2 below, the server may employ certain optimizations during recovery that work effectively only when the client's behavior during lock recovery is similar to the client's locking behavior prior to server failure.


9.3. Upgrading and Downgrading Locks
9.3. ロックのアップグレードとダウングレード

If a client has a write lock on a record, it can request an atomic downgrade of the lock to a read lock via the LOCK request, by setting the type to READ_LT. If the server supports atomic downgrade, the request will succeed. If not, it will return NFS4ERR_LOCK_NOTSUPP. The client should be prepared to receive this error and, if appropriate, report the error to the requesting application.

If a client has a write lock on a record, it can request an atomic downgrade of the lock to a read lock via the LOCK request, by setting the type to READ_LT. If the server supports atomic downgrade, the request will succeed. If not, it will return NFS4ERR_LOCK_NOTSUPP. The client should be prepared to receive this error and, if appropriate, report the error to the requesting application.

If a client has a read lock on a record, it can request an atomic upgrade of the lock to a write lock via the LOCK request by setting the type to WRITE_LT or WRITEW_LT. If the server does not support atomic upgrade, it will return NFS4ERR_LOCK_NOTSUPP. If the upgrade can be achieved without an existing conflict, the request will succeed. Otherwise, the server will return either NFS4ERR_DENIED or NFS4ERR_DEADLOCK. The error NFS4ERR_DEADLOCK is returned if the client issued the LOCK request with the type set to WRITEW_LT and the server has detected a deadlock. The client should be prepared to receive such errors and, if appropriate, report them to the requesting application.


9.4. Blocking Locks
9.4. ロックのブロック

Some clients require the support of blocking locks. The NFSv4 protocol must not rely on a callback mechanism and therefore is unable to notify a client when a previously denied lock has been granted. Clients have no choice but to continually poll for the lock. This presents a fairness problem. Two new lock types are added, READW and WRITEW, and are used to indicate to the server that the client is requesting a blocking lock. The server should maintain an ordered list of pending blocking locks. When the conflicting lock is released, the server may wait the lease period for the first waiting client to re-request the lock. After the lease period expires, the next waiting client request is allowed the lock. Clients are required to poll at an interval sufficiently small that it is likely to acquire the lock in a timely manner. The server is not required to maintain a list of pending blocked locks, as it is not used to provide correct operation but only to increase fairness. Because of the unordered nature of crash recovery, storing of lock state to stable storage would be required to guarantee ordered granting of blocking locks.

Some clients require the support of blocking locks. The NFSv4 protocol must not rely on a callback mechanism and therefore is unable to notify a client when a previously denied lock has been granted. Clients have no choice but to continually poll for the lock. This presents a fairness problem. Two new lock types are added, READW and WRITEW, and are used to indicate to the server that the client is requesting a blocking lock. The server should maintain an ordered list of pending blocking locks. When the conflicting lock is released, the server may wait the lease period for the first waiting client to re-request the lock. After the lease period expires, the next waiting client request is allowed the lock. Clients are required to poll at an interval sufficiently small that it is likely to acquire the lock in a timely manner. The server is not required to maintain a list of pending blocked locks, as it is not used to provide correct operation but only to increase fairness. Because of the unordered nature of crash recovery, storing of lock state to stable storage would be required to guarantee ordered granting of blocking locks.

Servers may also note the lock types and delay returning denial of the request to allow extra time for a conflicting lock to be released, allowing a successful return. In this way, clients can avoid the burden of needlessly frequent polling for blocking locks. The server should take care with the length of delay in the event that the client retransmits the request.


If a server receives a blocking lock request, denies it, and then later receives a non-blocking request for the same lock, which is also denied, then it should remove the lock in question from its list of pending blocking locks. Clients should use such a non-blocking request to indicate to the server that this is the last time they intend to poll for the lock, as may happen when the process requesting the lock is interrupted. This is a courtesy to the server, to prevent it from unnecessarily waiting a lease period before granting other lock requests. However, clients are not required to perform this courtesy, and servers must not depend on them doing so. Also, clients must be prepared for the possibility that this final locking request will be accepted.


9.5. Lease Renewal
9.5. リース更新

The purpose of a lease is to allow a server to remove stale locks that are held by a client that has crashed or is otherwise unreachable. It is not a mechanism for cache consistency, and lease renewals may not be denied if the lease interval has not expired.


The client can implicitly provide a positive indication that it is still active and that the associated state held at the server, for the client, is still valid. Any operation made with a valid clientid (DELEGPURGE, LOCK, LOCKT, OPEN, RELEASE_LOCKOWNER, or RENEW) or a valid stateid (CLOSE, DELEGRETURN, LOCK, LOCKU, OPEN, OPEN_CONFIRM, OPEN_DOWNGRADE, READ, SETATTR, or WRITE) informs the server to renew all of the leases for that client (i.e., all those sharing a given client ID). In the latter case, the stateid must not be one of the special stateids (anonymous stateid or READ bypass stateid).

クライアントは、それがまだアクティブであり、クライアントでサーバーに保持されている関連する状態がまだ有効であることを示す肯定的な指示を暗黙的に提供できます。有効なclientid(DELEGPURGE、LOCK、LOCKT、OPEN、RELEASE_LOCKOWNER、またはRENEW)または有効なstateid(CLOSE、DELEGRETURN、LOCK、LOCKU、OPEN、OPEN_CONFIRM、OPEN_DOWNGRADE、READ、SETATTR、またはWRITE)で行われた操作はサーバーに通知しますそのクライアントのリースをすべて更新します(つまり、特定のクライアントIDを共有するすべてのリース)。後者の場合、stateidは特別なstateid(匿名のstateidまたはREAD bypass stateid)の1つであってはなりません。

Note that if the client had restarted or rebooted, the client would not be making these requests without issuing the SETCLIENTID/ SETCLIENTID_CONFIRM sequence. The use of the SETCLIENTID/ SETCLIENTID_CONFIRM sequence (one that changes the client verifier) notifies the server to drop the locking state associated with the client. SETCLIENTID/SETCLIENTID_CONFIRM never renews a lease.

クライアントが再起動または再起動した場合、クライアントはSETCLIENTID / SETCLIENTID_CONFIRMシーケンスを発行せずにこれらの要求を作成しないことに注意してください。 SETCLIENTID / SETCLIENTID_CONFIRMシーケンス(クライアントベリファイアを変更するシーケンス)を使用すると、クライアントに関連付けられているロック状態を削除するようにサーバーに通知されます。 SETCLIENTID / SETCLIENTID_CONFIRMがリースを更新することはありません。

If the server has rebooted, the stateids (NFS4ERR_STALE_STATEID error) or the client ID (NFS4ERR_STALE_CLIENTID error) will not be valid, hence preventing spurious renewals.


This approach allows for low-overhead lease renewal, which scales well. In the typical case, no extra RPCs are required for lease renewal, and in the worst case, one RPC is required every lease period (i.e., a RENEW operation). The number of locks held by the client is not a factor since all state for the client is involved with the lease renewal action.


Since all operations that create a new lease also renew existing leases, the server must maintain a common lease expiration time for all valid leases for a given client. This lease time can then be easily updated upon implicit lease renewal actions.


9.6. Crash Recovery
9.6. クラッシュリカバリー

The important requirement in crash recovery is that both the client and the server know when the other has failed. Additionally, it is required that a client sees a consistent view of data across server restarts or reboots. All READ and WRITE operations that may have been queued within the client or network buffers must wait until the client has successfully recovered the locks protecting the READ and WRITE operations.


9.6.1. Client Failure and Recovery
9.6.1. クライアントの障害と回復

In the event that a client fails, the server may recover the client's locks when the associated leases have expired. Conflicting locks from another client may only be granted after this lease expiration. If the client is able to restart or reinitialize within the lease period, the client may be forced to wait the remainder of the lease period before obtaining new locks.


To minimize client delay upon restart, open and lock requests are associated with an instance of the client by a client-supplied verifier. This verifier is part of the initial SETCLIENTID call made by the client. The server returns a client ID as a result of the SETCLIENTID operation. The client then confirms the use of the client ID with SETCLIENTID_CONFIRM. The client ID in combination with an opaque owner field is then used by the client to identify the open-owner for OPEN. This chain of associations is then used to identify all locks for a particular client.


Since the verifier will be changed by the client upon each initialization, the server can compare a new verifier to the verifier associated with currently held locks and determine that they do not match. This signifies the client's new instantiation and subsequent loss of locking state. As a result, the server is free to release all locks held that are associated with the old client ID that was derived from the old verifier.


Note that the verifier must have the same uniqueness properties of the verifier for the COMMIT operation.


9.6.2. Server Failure and Recovery
9.6.2. サーバーの障害と回復

If the server loses locking state (usually as a result of a restart or reboot), it must allow clients time to discover this fact and re-establish the lost locking state. The client must be able to re-establish the locking state without having the server deny valid requests because the server has granted conflicting access to another client. Likewise, if there is the possibility that clients have not yet re-established their locking state for a file, the server must disallow READ and WRITE operations for that file. The duration of this recovery period is equal to the duration of the lease period.


A client can determine that server failure (and thus loss of locking state) has occurred, when it receives one of two errors. The NFS4ERR_STALE_STATEID error indicates a stateid invalidated by a reboot or restart. The NFS4ERR_STALE_CLIENTID error indicates a client ID invalidated by reboot or restart. When either of these is received, the client must establish a new client ID (see Section 9.1.1) and re-establish the locking state as discussed below.

クライアントは、2つのエラーのいずれかを受け取ったときに、サーバー障害(およびロック状態の喪失)が発生したと判断できます。 NFS4ERR_STALE_STATEIDエラーは、再起動または再起動によって無効にされた状態IDを示します。 NFS4ERR_STALE_CLIENTIDエラーは、クライアントIDが再起動または再起動によって無効化されたことを示します。これらのいずれかが受信されると、クライアントは新しいクライアントID(セクション9.1.1を参照)を確立し、以下で説明するようにロック状態を再確立する必要があります。

The period of special handling of locking and READs and WRITEs, equal in duration to the lease period, is referred to as the "grace period". During the grace period, clients recover locks and the associated state by reclaim-type locking requests (i.e., LOCK requests with reclaim set to TRUE and OPEN operations with a claim type of either CLAIM_PREVIOUS or CLAIM_DELEGATE_PREV). During the grace period, the server must reject READ and WRITE operations and non-reclaim locking requests (i.e., other LOCK and OPEN operations) with an error of NFS4ERR_GRACE.


If the server can reliably determine that granting a non-reclaim request will not conflict with reclamation of locks by other clients, the NFS4ERR_GRACE error does not have to be returned and the non-reclaim client request can be serviced. For the server to be able to service READ and WRITE operations during the grace period, it must again be able to guarantee that no possible conflict could arise between an impending reclaim locking request and the READ or WRITE operation. If the server is unable to offer that guarantee, the NFS4ERR_GRACE error must be returned to the client.


For a server to provide simple, valid handling during the grace period, the easiest method is to simply reject all non-reclaim locking requests and READ and WRITE operations by returning the NFS4ERR_GRACE error. However, a server may keep information about granted locks in stable storage. With this information, the server could determine if a regular lock or READ or WRITE operation can be safely processed.


For example, if a count of locks on a given file is available in stable storage, the server can track reclaimed locks for the file, and when all reclaims have been processed, non-reclaim locking requests may be processed. This way, the server can ensure that non-reclaim locking requests will not conflict with potential reclaim requests. With respect to I/O requests, if the server is able to determine that there are no outstanding reclaim requests for a file by information from stable storage or another similar mechanism, the processing of I/O requests could proceed normally for the file.

たとえば、特定のファイルのロックの数が安定したストレージで利用できる場合、サーバーはファイルの再利用されたロックを追跡でき、すべての再利用が処理されると、非再利用のロック要求が処理される場合があります。このようにして、サーバーは非再利用ロック要求が潜在的な再利用要求と競合しないようにすることができます。 I / O要求に関して、サーバーが安定したストレージまたは他の同様のメカニズムからの情報によってファイルの未解決の再利用要求がないと判断できる場合、I / O要求の処理はファイルに対して正常に続行できます。

To reiterate, for a server that allows non-reclaim lock and I/O requests to be processed during the grace period, it MUST determine that no lock subsequently reclaimed will be rejected and that no lock subsequently reclaimed would have prevented any I/O operation processed during the grace period.

繰り返しますが、非再利用ロックとI / O要求が猶予期間中に処理されることを許可するサーバーでは、その後再利用されるロックは拒否されず、その後再利用されるロックはI / O操作を妨げなかったと判断する必要があります。猶予期間中に処理されました。

Clients should be prepared for the return of NFS4ERR_GRACE errors for non-reclaim lock and I/O requests. In this case, the client should employ a retry mechanism for the request. A delay (on the order of several seconds) between retries should be used to avoid overwhelming the server. Further discussion of the general issue is included in [Floyd]. The client must account for the server that is able to perform I/O and non-reclaim locking requests within the grace period as well as those that cannot do so.

クライアントは、非再利用ロックおよびI / O要求に対してNFS4ERR_GRACEエラーが返されるように準備する必要があります。この場合、クライアントは要求に対して再試行メカニズムを採用する必要があります。サーバーが過負荷にならないように、再試行間の遅延(数秒程度)を使用する必要があります。一般的な問題の詳細については、[Floyd]に記載されています。クライアントは、猶予期間内にI / Oおよび非再利用ロック要求を実行できるサーバーと、そうできないサーバーを説明する必要があります。

A reclaim-type locking request outside the server's grace period can only succeed if the server can guarantee that no conflicting lock or I/O request has been granted since reboot or restart.

A reclaim-type locking request outside the server's grace period can only succeed if the server can guarantee that no conflicting lock or I/O request has been granted since reboot or restart.

A server may, upon restart, establish a new value for the lease period. Therefore, clients should, once a new client ID is established, refetch the lease_time attribute and use it as the basis for lease renewal for the lease associated with that server. However, the server must establish, for this restart event, a grace period at least as long as the lease period for the previous server instantiation. This allows the client state obtained during the previous server instance to be reliably re-established.


9.6.3. Network Partitions and Recovery
9.6.3. ネットワークパーティションとリカバリ

If the duration of a network partition is greater than the lease period provided by the server, the server will have not received a lease renewal from the client. If this occurs, the server may cancel the lease and free all locks held for the client. As a result, all stateids held by the client will become invalid or stale. Once the client is able to reach the server after such a network partition, all I/O submitted by the client with the now invalid stateids will fail with the server returning the error NFS4ERR_EXPIRED. Once this error is received, the client will suitably notify the application that held the lock.

ネットワークパーティションの期間がサーバーによって提供されるリース期間よりも長い場合、サーバーはクライアントからリースの更新を受信して​​いません。これが発生した場合、サーバーはリースをキャンセルし、クライアントのために保持していたすべてのロックを解放します。その結果、クライアントが保持するすべての状態IDが無効または古くなります。このようなネットワークパーティションの後でクライアントがサーバーに到達すると、無効な状態IDでクライアントから送信されたすべてのI / Oが失敗し、サーバーはエラーNFS4ERR_EXPIREDを返します。このエラーが受信されると、クライアントは、ロックを保持していたアプリケーションに適切に通知します。 Courtesy Locks 礼儀ロック

As a courtesy to the client or as an optimization, the server may continue to hold locks, including delegations, on behalf of a client for which recent communication has extended beyond the lease period, delaying the cancellation of the lease. If the server receives a lock or I/O request that conflicts with one of these courtesy locks or if it runs out of resources, the server MAY cause lease cancellation to occur at that time and henceforth return NFS4ERR_EXPIRED when any of the stateids associated with the freed locks is used. If lease cancellation has not occurred and the server receives a lock or I/O request that conflicts with one of the courtesy locks, the requirements are as follows:

クライアントへの礼儀として、または最適化として、サーバーは、最近の通信がリース期間を超えて延長されたクライアントに代わって、委任を含むロックを保持し続け、リースのキャンセルを遅らせます。サーバーがこれらのサービスロックのいずれかと競合するロックまたはI / O要求を受信した場合、またはリソースが不足した場合、サーバーはその時点でリースのキャンセルを発生させ、それ以降、解放されたロックが使用されます。リースのキャンセルが行われておらず、サーバーがロックまたはI / O要求を受信して​​、サービスロックのいずれかと競合する場合、要件は次のとおりです。

o In the case of a courtesy lock that is not a delegation, it MUST free the courtesy lock and grant the new request.

o 委任ではないサービスロックの場合は、サービスロックを解放し、新しいリクエストを許可する必要があります。

o In the case of a lock or an I/O request that conflicts with a delegation that is being held as a courtesy lock, the server MAY delay resolution of the request but MUST NOT reject the request and MUST free the delegation and grant the new request eventually.

o 礼儀ロックとして保持されている委任と競合するロックまたはI / O要求の場合、サーバーは要求の解決を遅らせてもよいが、要求を拒否してはならず、委任を解放して新しい要求を許可しなければならない(MUST)最終的に。

o In the case of a request for a delegation that conflicts with a delegation that is being held as a courtesy lock, the server MAY grant the new request or not as it chooses, but if it grants the conflicting request, the delegation held as a courtesy lock MUST be freed.

o 礼儀ロックとして保持されている委任と競合する委任の要求の場合、サーバーは選択したとおりに新しい要求を許可するかどうかは問わないが、競合する要求を許可する場合、委任は礼儀として保持されるロックを解放する必要があります。

If the server does not reboot or cancel the lease before the network partition is healed, when the original client tries to access a courtesy lock that was freed, the server SHOULD send back an NFS4ERR_BAD_STATEID to the client. If the client tries to access a courtesy lock that was not freed, then the server SHOULD mark all of the courtesy locks as implicitly being renewed.

ネットワークパーティションが修復される前にサーバーが再起動またはリースをキャンセルしない場合、元のクライアントが解放されたサービスロックにアクセスしようとすると、サーバーはクライアントにNFS4ERR_BAD_STATEIDを送信する必要があります(SHOULD)。クライアントが解放されなかったサービスロックにアクセスしようとすると、サーバーはサービスロックのすべてに暗黙的に更新されるものとしてマークを付ける必要があります(SHOULD)。 Lease Cancellation リースキャンセル

As a result of lease expiration, leases may be canceled, either immediately upon expiration or subsequently, depending on the occurrence of a conflicting lock or extension of the period of partition beyond what the server will tolerate.


When a lease is canceled, all locking state associated with it is freed, and the use of any of the associated stateids will result in NFS4ERR_EXPIRED being returned. Similarly, the use of the associated clientid will result in NFS4ERR_EXPIRED being returned.


The client should recover from this situation by using SETCLIENTID followed by SETCLIENTID_CONFIRM, in order to establish a new clientid. Once a lock is obtained using this clientid, a lease will be established.

クライアントは、新しいクライアントIDを確立するために、SETCLIENTIDに続いてSETCLIENTID_CONFIRMを使用して、この状況から回復する必要があります。このclientidを使用してロックが取得されると、リースが確立されます。 Client's Reaction to a Freed Lock Client's Reaction to a Freed Lock

There is no way for a client to predetermine how a given server is going to behave during a network partition. When the partition heals, the client still has either all of its locks, some of its locks, or none of them. The client will be able to examine the various error return values to determine its response.




All locks have been freed as a result of a lease cancellation that occurred during the partition. The client should use a SETCLIENTID to recover.




The current lock has been revoked before, during, or after the partition. The client SHOULD handle this error as it normally would.




The current lock has been revoked/released during the partition, and the server did not reboot. Other locks MAY still be renewed. The client need not do a SETCLIENTID and instead SHOULD probe via a RENEW call.




The current lock has been revoked during the partition, and the server rebooted. The server might have no information on the other locks. They may still be renewable.

The current lock has been revoked during the partition, and the server rebooted. The server might have no information on the other locks. They may still be renewable.



The client's locks have been revoked during the partition, and the server rebooted. None of the client's locks will be renewable.




The server has not rebooted. The client SHOULD handle this error as it normally would.

サーバーは再起動していません。クライアントは、通常どおりにこのエラーを処理する必要があります(SHOULD)。 Edge Conditions エッジ条件

When a network partition is combined with a server reboot, then both the server and client have responsibilities to ensure that the client does not reclaim a lock that it should no longer be able to access. Briefly, those are:


o Client's responsibility: A client MUST NOT attempt to reclaim any locks that it did not hold at the end of its most recent successfully established client lease.

o クライアントの責任:クライアントは、正常に確立された最新のクライアントリースの最後に保持しなかったロックを取り戻そうとしてはなりません。

o Server's responsibility: A server MUST NOT allow a client to reclaim a lock unless it knows that it could not have since granted a conflicting lock. However, in deciding whether a conflicting lock could have been granted, it is permitted to assume that its clients are responsible, as above.

o サーバーの責任:サーバーは、競合するロックを許可できなかったことがわかっていない限り、クライアントがロックを取り戻すことを許可してはなりません。ただし、競合するロックが許可されている可能性があるかどうかを判断する場合、上記のように、そのクライアントに責任があると想定することが許可されます。

A server may consider a client's lease "successfully established" once it has received an OPEN operation from that client.


The above are directed to CLAIM_PREVIOUS reclaims and not to CLAIM_DELEGATE_PREV reclaims, which generally do not involve a server reboot. However, when a server persistently stores delegation information to support CLAIM_DELEGATE_PREV across a period in which both client and server are down at the same time, similar strictures apply.


The next sections give examples showing what can go wrong if these responsibilities are neglected and also provide examples of server implementation strategies that could meet a server's responsibilities.

次のセクションでは、これらの責任が無視された場合に問題が発生する可能性があることを示す例と、サーバーの責任を満たすことができるサーバー実装戦略の例を示します。 First Server Edge Condition 最初のサーバーエッジの状態

The first edge condition has the following scenario:


1. Client A acquires a lock.

1. Client A acquires a lock.

2. Client A and the server experience mutual network partition, such that client A is unable to renew its lease.

2. クライアントAとサーバーで相互ネットワークパーティションが発生しているため、クライアントAはリースを更新できません。

3. Client A's lease expires, so the server releases the lock.

3. クライアントAのリースが期限切れになるため、サーバーはロックを解放します。

4. Client B acquires a lock that would have conflicted with that of client A.

4. クライアントBは、クライアントAのロックと競合するロックを取得します。

5. Client B releases the lock.

5. Client B releases the lock.

6. The server reboots.

6. サーバーが再起動します。

7. The network partition between client A and the server heals.

7. クライアントAとサーバー間のネットワークパーティションが修復されます。

8. Client A issues a RENEW operation and gets back an NFS4ERR_STALE_CLIENTID.

8. クライアントAはRENEW操作を発行し、NFS4ERR_STALE_CLIENTIDを返します。

9. Client A reclaims its lock within the server's grace period.

9. クライアントAは、サーバーの猶予期間内にロックを取り戻します。

Thus, at the final step, the server has erroneously granted client A's lock reclaim. If client B modified the object the lock was protecting, client A will experience object corruption.

したがって、最後のステップで、サーバーは誤ってクライアントAのロック再利用を許可しました。ロックが保護していたオブジェクトをクライアントBが変更した場合、クライアントAはオブジェクトの破損を経験します。 Second Server Edge Condition 2番目のサーバーエッジの状態

The second known edge condition follows:


1. Client A acquires a lock.

1. クライアントAがロックを取得します。

2. The server reboots.

2. サーバーが再起動します。

3. Client A and the server experience mutual network partition, such that client A is unable to reclaim its lock within the grace period.

3. クライアントAとサーバーは相互ネットワークパーティションを経験しているため、クライアントAは猶予期間内にロックを取り戻すことができません。

4. The server's reclaim grace period ends. Client A has no locks recorded on the server.

4. サーバーの再利用猶予期間が終了します。クライアントAには、サーバーに記録されたロックはありません。

5. Client B acquires a lock that would have conflicted with that of client A.

5. クライアントBは、クライアントAのロックと競合するロックを取得します。

6. Client B releases the lock.

6. クライアントBがロックを解放します。

7. The server reboots a second time.

7. サーバーがもう一度再起動します。

8. The network partition between client A and the server heals.

8. クライアントAとサーバー間のネットワークパーティションが修復されます。

9. Client A issues a RENEW operation and gets back an NFS4ERR_STALE_CLIENTID.

9. クライアントAはRENEW操作を発行し、NFS4ERR_STALE_CLIENTIDを返します。

10. Client A reclaims its lock within the server's grace period.

10. クライアントAは、サーバーの猶予期間内にロックを取り戻します。

As with the first edge condition, the final step of the scenario of the second edge condition has the server erroneously granting client A's lock reclaim.

最初のエッジ条件と同様に、2番目のエッジ条件のシナリオの最後のステップでは、サーバーが誤ってクライアントAにロックの再利用を許可します。 Handling Server Edge Conditions サーバーエッジ条件の処理

In both of the above examples, the client attempts reclaim of a lock that it held at the end of its most recent successfully established lease; thus, it has fulfilled its responsibility.


The server, however, has failed, by granting a reclaim, despite having granted a conflicting lock since the reclaimed lock was last held.

The server, however, has failed, by granting a reclaim, despite having granted a conflicting lock since the reclaimed lock was last held.

Solving these edge conditions requires that the server either (1) assume after it reboots that an edge condition occurs, and thus return NFS4ERR_NO_GRACE for all reclaim attempts, or (2) record some information in stable storage. The amount of information the server records in stable storage is in inverse proportion to how harsh the server wants to be whenever the edge conditions occur. The server that is completely tolerant of all edge conditions will record in stable storage every lock that is acquired, removing the lock record from stable storage only when the lock is unlocked by the client and the lock's owner advances the sequence number such that the lock release is not the last stateful event for the owner's sequence. For the two aforementioned edge conditions, the harshest a server can be, and still support a grace period for reclaims, requires that the server record in stable storage some minimal information. For example, a server implementation could, for each client, save in stable storage a record containing:


o the client's id string.

o クライアントのID文字列。

o a boolean that indicates if the client's lease expired or if there was administrative intervention (see Section 9.8) to revoke a byte-range lock, share reservation, or delegation.

o クライアントのリースが期限切れになったかどうか、またはバイト範囲ロック、共有予約、または委任を取り消すための管理上の介入(セクション9.8を参照)があったかどうかを示すブール値。

o a timestamp that is updated the first time after a server boot or reboot the client acquires byte-range locking, share reservation, or delegation state on the server. The timestamp need not be updated on subsequent lock requests until the server reboots.

o a timestamp that is updated the first time after a server boot or reboot the client acquires byte-range locking, share reservation, or delegation state on the server. The timestamp need not be updated on subsequent lock requests until the server reboots.

The server implementation would also record in stable storage the timestamps from the two most recent server reboots.


Assuming the above record keeping, for the first edge condition, after the server reboots, the record that client A's lease expired means that another client could have acquired a conflicting record lock, share reservation, or delegation. Hence, the server must reject a reclaim from client A with the error NFS4ERR_NO_GRACE or NFS4ERR_RECLAIM_BAD.


For the second edge condition, after the server reboots for a second time, the record that the client had an unexpired record lock, share reservation, or delegation established before the server's previous incarnation means that the server must reject a reclaim from client A with the error NFS4ERR_NO_GRACE or NFS4ERR_RECLAIM_BAD.


Regardless of the level and approach to record keeping, the server MUST implement one of the following strategies (which apply to reclaims of share reservations, byte-range locks, and delegations):


1. Reject all reclaims with NFS4ERR_NO_GRACE. This is extremely harsh but is necessary if the server does not want to record lock state in stable storage.

1. NFS4ERR_NO_GRACEを使用してすべての再利用を拒否します。これは非常に厳しいですが、サーバーが安定したストレージにロック状態を記録したくない場合に必要です。

2. Record sufficient state in stable storage to meet its responsibilities. In doubt, the server should err on the side of being harsh.

2. その責任を満たすために、安定した保管場所に十分な状態を記録します。疑わしいことに、サーバーは過酷であるという誤解を招くはずです。

In the event that, after a server reboot, the server determines that there is unrecoverable damage or corruption to stable storage, then for all clients and/or locks affected, the server MUST return NFS4ERR_NO_GRACE.

サーバーの再起動後、サーバーが安定したストレージに回復不可能な損傷または破損があると判断した場合、影響を受けるすべてのクライアントまたはロック、あるいはその両方について、サーバーはNFS4ERR_NO_GRACEを返さなければなりません(MUST)。 Client Edge Condition Client Edge Condition

A third edge condition affects the client and not the server. If the server reboots in the middle of the client reclaiming some locks and then a network partition is established, the client might be in the situation of having reclaimed some, but not all, locks. In that case, a conservative client would assume that the non-reclaimed locks were revoked.


The third known edge condition follows:


1. Client A acquires a lock 1.

1. クライアントAはロック1を取得します。

2. Client A acquires a lock 2.

2. Client A acquires a lock 2.

3. The server reboots.

3. サーバーが再起動します。

4. Client A issues a RENEW operation and gets back an NFS4ERR_STALE_CLIENTID.

4. クライアントAはRENEW操作を発行し、NFS4ERR_STALE_CLIENTIDを返します。

5. Client A reclaims its lock 1 within the server's grace period.

5. クライアントAは、サーバーの猶予期間内にロック1を取り戻します。

6. Client A and the server experience mutual network partition, such that client A is unable to reclaim its remaining locks within the grace period.

6. クライアントAとサーバーは相互ネットワークパーティションを経験するため、猶予期間内にクライアントAは残りのロックを再利用できません。

7. The server's reclaim grace period ends.

7. サーバーの再利用猶予期間が終了します。

8. Client B acquires a lock that would have conflicted with client A's lock 2.

8. クライアントBは、クライアントAのロックと競合するロックを取得します2。

9. Client B releases the lock.

9. クライアントBがロックを解放します。

10. The server reboots a second time.

10. サーバーがもう一度再起動します。

11. The network partition between client A and the server heals.

11. クライアントAとサーバー間のネットワークパーティションが修復されます。

12. Client A issues a RENEW operation and gets back an NFS4ERR_STALE_CLIENTID.

12. クライアントAはRENEW操作を発行し、NFS4ERR_STALE_CLIENTIDを返します。

13. Client A reclaims both lock 1 and lock 2 within the server's grace period.

13. クライアントAは、サーバーの猶予期間内にロック1とロック2の両方を取り戻します。

At the last step, the client reclaims lock 2 as if it had held that lock continuously, when in fact a conflicting lock was granted to client B.


This occurs because the client failed its responsibility, by attempting to reclaim lock 2 even though it had not held that lock at the end of the lease that was established by the SETCLIENTID after the first server reboot. (The client did hold lock 2 on a previous lease, but it is only the most recent lease that matters.)

これは、最初のサーバーの再起動後にSETCLIENTIDによって確立されたリースの最後にロック2を保持していなくても、クライアントがロック2を再利用しようとしたために、クライアントがその責任を果たせなかったために発生します。 (クライアントは以前のリースでロック2を保持していましたが、問題になるのは最新のリースのみです。)

A server could avoid this situation by rejecting the reclaim of lock 2. However, to do so accurately, it would have to ensure that additional information about individual locks held survives a reboot. Server implementations are not required to do that, so the client must not assume that the server will.


Instead, a client MUST reclaim only those locks that it successfully acquired from the previous server instance, omitting any that it failed to reclaim before a new reboot. Thus, in the last step above, client A should reclaim only lock 1.

代わりに、クライアントは以前のサーバーインスタンスから正常に取得したロックのみを再利用する必要があり、新しい再起動前に再利用に失敗したロックは省略します。したがって、上記の最後のステップでは、クライアントAはロック1のみを取り戻す必要があります。 Client's Handling of Reclaim Errors 再利用エラーのクライアントの処理

A mandate for the client's handling of the NFS4ERR_NO_GRACE and NFS4ERR_RECLAIM_BAD errors is outside the scope of this specification, since the strategies for such handling are very dependent on the client's operating environment. However, one potential approach is described below.


When the client's reclaim fails, it could examine the change attribute of the objects the client is trying to reclaim state for, and use that to determine whether to re-establish the state via normal OPEN or LOCK requests. This is acceptable, provided the client's operating environment allows it. In other words, the client implementer is advised to document the behavior for his users. The client could also inform the application that its byte-range lock or share reservations (whether they were delegated or not) have been lost, such as via a UNIX signal, a GUI pop-up window, etc. See Section 10.5 for a discussion of what the client should do for dealing with unreclaimed delegations on client state.


For further discussion of revocation of locks, see Section 9.8.


9.7. Recovery from a Lock Request Timeout or Abort
9.7. ロックリクエストのタイムアウトまたは中止からの回復

In the event a lock request times out, a client may decide to not retry the request. The client may also abort the request when the process for which it was issued is terminated (e.g., in UNIX due to a signal). It is possible, though, that the server received the request and acted upon it. This would change the state on the server without the client being aware of the change. It is paramount that the client resynchronize state with the server before it attempts any other operation that takes a seqid and/or a stateid with the same state-owner. This is straightforward to do without a special resynchronize operation.


Since the server maintains the last lock request and response received on the state-owner, for each state-owner, the client should cache the last lock request it sent such that the lock request did not receive a response. From this, the next time the client does a lock operation for the state-owner, it can send the cached request, if there is one, and if the request was one that established state (e.g., a LOCK or OPEN operation), the server will return the cached result or, if it never saw the request, perform it. The client can follow up with a request to remove the state (e.g., a LOCKU or CLOSE operation). With this approach, the sequencing and stateid information on the client and server for the given state-owner will resynchronize, and in turn the lock state will resynchronize.


9.8. Server Revocation of Locks
9.8. ロックのサーバー失効

At any point, the server can revoke locks held by a client and the client must be prepared for this event. When the client detects that its locks have been or may have been revoked, the client is responsible for validating the state information between itself and the server. Validating locking state for the client means that it must verify or reclaim state for each lock currently held.


The first instance of lock revocation is upon server reboot or re-initialization. In this instance, the client will receive an error (NFS4ERR_STALE_STATEID or NFS4ERR_STALE_CLIENTID) and the client will proceed with normal crash recovery as described in the previous section.


The second lock revocation event is the inability to renew the lease before expiration. While this is considered a rare or unusual event, the client must be prepared to recover. Both the server and client will be able to detect the failure to renew the lease and are capable of recovering without data corruption. For the server, it tracks the last renewal event serviced for the client and knows when the lease will expire. Similarly, the client must track operations that will renew the lease period. Using the time that each such request was sent and the time that the corresponding reply was received, the client should bound the time that the corresponding renewal could have occurred on the server and thus determine if it is possible that a lease period expiration could have occurred.


The third lock revocation event can occur as a result of administrative intervention within the lease period. While this is considered a rare event, it is possible that the server's administrator has decided to release or revoke a particular lock held by the client. As a result of revocation, the client will receive an error of NFS4ERR_ADMIN_REVOKED. In this instance, the client may assume that only the state-owner's locks have been lost. The client notifies the lock holder appropriately. The client cannot assume that the lease period has been renewed as a result of a failed operation.


When the client determines the lease period may have expired, the client must mark all locks held for the associated lease as "unvalidated". This means the client has been unable to re-establish or confirm the appropriate lock state with the server. As described in Section 9.6, there are scenarios in which the server may grant conflicting locks after the lease period has expired for a client. When it is possible that the lease period has expired, the client must validate each lock currently held to ensure that a conflicting lock has not been granted. The client may accomplish this task by issuing an I/O request; if there is no relevant I/O pending, a zero-length read specifying the stateid associated with the lock in question can be synthesized to trigger the renewal. If the response to the request is success, the client has validated all of the locks governed by that stateid and re-established the appropriate state between itself and the server.

クライアントは、リース期間が終了した可能性があると判断した場合、関連付けられたリースに対して保持されているすべてのロックを「未検証」としてマークする必要があります。これは、クライアントがサーバーとの適切なロック状態を再確立または確認できなかったことを意味します。セクション9.6で説明したように、クライアントのリース期間が終了した後、サーバーが競合するロックを許可するシナリオがあります。リース期間が終了した可能性がある場合、クライアントは現在保持されている各ロックを検証して、競合するロックが許可されていないことを確認する必要があります。クライアントは、I / O要求を発行してこのタスクを実行できます。保留中の関連するI / Oがない場合は、問題のロックに関連付けられた状態IDを指定する長さ0の読み取りを合成して、更新をトリガーできます。要求への応答が成功した場合、クライアントはその状態IDによって管理されるすべてのロックを検証し、クライアントとサーバーの間の適切な状態を再確立しました。

If the I/O request is not successful, then one or more of the locks associated with the stateid were revoked by the server, and the client must notify the owner.

I / O要求が成功しない場合、stateidに関連付けられた1つ以上のロックがサーバーによって取り消され、クライアントは所有者に通知する必要があります。

9.9. Share Reservations
9.9. 予約を共有する

A share reservation is a mechanism to control access to a file. It is a separate and independent mechanism from byte-range locking. When a client opens a file, it issues an OPEN operation to the server specifying the type of access required (READ, WRITE, or BOTH) and the type of access to deny others (OPEN4_SHARE_DENY_NONE, OPEN4_SHARE_DENY_READ, OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH). If the OPEN fails, the client will fail the application's open request.

共有予約は、ファイルへのアクセスを制御するメカニズムです。これは、バイト範囲ロックとは別の独立したメカニズムです。クライアントがファイルを開くと、必要なアクセスのタイプ(READ、WRITE、またはBOTH)と他を拒否するアクセスのタイプ(OPEN4_SHARE_DENY_NONE、OPEN4_SHARE_DENY_WRITE、またはOPEN4_SHARE_DENY_BOTH)を指定して、OPEN操作をサーバーに発行します。 OPENが失敗すると、クライアントはアプリケーションのオープンリクエストに失敗します。

Pseudo-code definition of the semantics:


if (request.access == 0) return (NFS4ERR_INVAL) else if ((request.access & file_state.deny) || (request.deny & file_state.access)) return (NFS4ERR_DENIED)

if(request.access == 0)return(NFS4ERR_INVAL)else if((request.access&file_state.deny)||(request.deny&file_state.access))return(NFS4ERR_DENIED)

This checking of share reservations on OPEN is done with no exception for an existing OPEN for the same open-owner.


The constants used for the OPEN and OPEN_DOWNGRADE operations for the access and deny fields are as follows:


   const OPEN4_SHARE_ACCESS_READ   = 0x00000001;
   const OPEN4_SHARE_ACCESS_WRITE  = 0x00000002;
   const OPEN4_SHARE_ACCESS_BOTH   = 0x00000003;
   const OPEN4_SHARE_DENY_NONE     = 0x00000000;
   const OPEN4_SHARE_DENY_READ     = 0x00000001;
   const OPEN4_SHARE_DENY_WRITE    = 0x00000002;
   const OPEN4_SHARE_DENY_BOTH     = 0x00000003;
9.10. OPEN/CLOSE Operations
9.10. OPEN / CLOSE操作

To provide correct share semantics, a client MUST use the OPEN operation to obtain the initial filehandle and indicate the desired access and what access, if any, to deny. Even if the client intends to use one of the special stateids (anonymous stateid or READ bypass stateid), it must still obtain the filehandle for the regular file with the OPEN operation so the appropriate share semantics can be applied. Clients that do not have a deny mode built into their programming interfaces for opening a file should request a deny mode of OPEN4_SHARE_DENY_NONE.


The OPEN operation with the CREATE flag also subsumes the CREATE operation for regular files as used in previous versions of the NFS protocol. This allows a create with a share to be done atomically.


The CLOSE operation removes all share reservations held by the open-owner on that file. If byte-range locks are held, the client SHOULD release all locks before issuing a CLOSE. The server MAY free all outstanding locks on CLOSE, but some servers may not support the CLOSE of a file that still has byte-range locks held. The server MUST return failure, NFS4ERR_LOCKS_HELD, if any locks would exist after the CLOSE.

CLOSE操作は、そのファイルのオープンオーナーによって保持されているすべての共有予約を削除します。バイト範囲のロックが保持されている場合、クライアントはCLOSEを発行する前にすべてのロックを解放する必要があります(SHOULD)。サーバーはCLOSEですべての未解決のロックを解放してもかまいませんが、一部のサーバーは、バイト範囲のロックが保持されているファイルのCLOSEをサポートしない場合があります。 CLOSEの後にロックが存在する場合、サーバーは失敗、NFS4ERR_LOCKS_HELDを返す必要があります。

The LOOKUP operation will return a filehandle without establishing any lock state on the server. Without a valid stateid, the server will assume that the client has the least access. For example, if one client opened a file with OPEN4_SHARE_DENY_BOTH and another client accesses the file via a filehandle obtained through LOOKUP, the second client could only read the file using the special READ bypass stateid. The second client could not WRITE the file at all because it would not have a valid stateid from OPEN and the special anonymous stateid would not be allowed access.

LOOKUP操作は、サーバーでロック状態を確立せずにファイルハンドルを返します。有効な状態IDがない場合、サーバーはクライアントのアクセスが最小であると想定します。たとえば、あるクライアントがOPEN4_SHARE_DENY_BOTHを使用してファイルを開き、別のクライアントがLOOKUPを通じて取得したファイルハンドルを介してファイルにアクセスした場合、2番目のクライアントは特別なREADバイパス状態IDを使用してのみファイルを読み取ることができます。 OPENからの有効な状態IDがなく、特別な匿名の状態IDがアクセスを許可されていないため、2番目のクライアントはファイルをまったく書き込むことができませんでした。

9.10.1. Close and Retention of State Information
9.10.1. 状態情報のクローズと保持

Since a CLOSE operation requests deallocation of a stateid, dealing with retransmission of the CLOSE may pose special difficulties, since the state information, which normally would be used to determine the state of the open file being designated, might be deallocated, resulting in an NFS4ERR_BAD_STATEID error.


Servers may deal with this problem in a number of ways. To provide the greatest degree of assurance that the protocol is being used properly, a server should, rather than deallocate the stateid, mark it as close-pending, and retain the stateid with this status, until later deallocation. In this way, a retransmitted CLOSE can be recognized since the stateid points to state information with this distinctive status, so that it can be handled without error.


When adopting this strategy, a server should retain the state information until the earliest of:


o Another validly sequenced request for the same open-owner, that is not a retransmission.

o 同じオープンオーナーに対する有効にシーケンス化された別のリクエスト。これは再送信ではありません。

o The time that an open-owner is freed by the server due to period with no activity.

o 活動のない期間のために、オープンオーナーがサーバーによって解放された時間。

o All locks for the client are freed as a result of a SETCLIENTID.

o クライアントのすべてのロックは、SETCLIENTIDの結果として解放されます。

Servers may avoid this complexity, at the cost of less complete protocol error checking, by simply responding NFS4_OK in the event of a CLOSE for a deallocated stateid, on the assumption that this case must be caused by a retransmitted close. When adopting this approach, it is desirable to at least log an error when returning a no-error indication in this situation. If the server maintains a reply-cache mechanism, it can verify that the CLOSE is indeed a retransmission and avoid error logging in most cases.


9.11. Open Upgrade and Downgrade
9.11. オープンアップグレードとダウングレード

When an OPEN is done for a file and the open-owner for which the open is being done already has the file open, the result is to upgrade the open file status maintained on the server to include the access and deny bits specified by the new OPEN as well as those for the existing OPEN. The result is that there is one open file, as far as the protocol is concerned, and it includes the union of the access and deny bits for all of the OPEN requests completed. Only a single CLOSE will be done to reset the effects of both OPENs. Note that the client, when issuing the OPEN, may not know that the same file is in fact being opened. The above only applies if both OPENs result in the OPENed object being designated by the same filehandle.

ファイルに対してOPENが行われ、オープンが行われているオープンオーナーがすでにファイルを開いている場合、結果はサーバー上で維持されているオープンファイルのステータスをアップグレードして、新しいファイルで指定されたアクセスおよび拒否ビットを含めます。 OPENおよび既存のOPENのOPEN。その結果、プロトコルに関する限り、1つのオープンファイルがあり、完了したすべてのOPEN要求のアクセスおよび拒否ビットの結合が含まれます。両方のOPENの影響をリセットするために、単一のCLOSEのみが実行されます。クライアントは、OPENを発行するときに、同じファイルが実際に開かれていることを認識していない場合があることに注意してください。上記は、両方のOPENの結果、OPENedオブジェクトが同じファイルハンドルによって指定される場合にのみ適用されます。

When the server chooses to export multiple filehandles corresponding to the same file object and returns different filehandles on two different OPENs of the same file object, the server MUST NOT "OR" together the access and deny bits and coalesce the two open files. Instead, the server must maintain separate OPENs with separate stateids and will require separate CLOSEs to free them.

サーバーが同じファイルオブジェクトに対応する複数のファイルハンドルをエクスポートすることを選択し、同じファイルオブジェクトの2つの異なるOPENで異なるファイルハンドルを返す場合、サーバーはアクセスと拒否ビットを一緒に「OR」して、2つの開いているファイルを結合してはなりません(MUST NOT)。代わりに、サーバーは個別の状態IDを持つ個別のOPENを維持する必要があり、それらを解放するには個別のCLOSEが必要になります。

When multiple open files on the client are merged into a single open file object on the server, the close of one of the open files (on the client) may necessitate change of the access and deny status of the open file on the server. This is because the union of the access and deny bits for the remaining opens may be smaller (i.e., a proper subset) than previously. The OPEN_DOWNGRADE operation is used to make the necessary change, and the client should use it to update the server so that share reservation requests by other clients are handled properly. The stateid returned has the same "other" field as that passed to the server. The seqid value in the returned stateid MUST be incremented (Section 9.1.4), even in situations in which there has been no change to the access and deny bits for the file.

クライアント上の複数の開いているファイルがサーバー上の単一の開いているファイルオブジェクトにマージされると、開いているファイルの1つ(クライアント上)を閉じると、アクセスの変更とサーバー上の開いているファイルのステータスの拒否が必要になる場合があります。これは、残りのオープンのアクセスおよび拒否ビットの和集合が以前よりも小さい(つまり、適切なサブセットである)可能性があるためです。 OPEN_DOWNGRADE操作は必要な変更を行うために使用され、クライアントは他のクライアントによる共有予約要求が適切に処理されるようにサーバーを更新するためにそれを使用する必要があります。返された状態IDには、サーバーに渡されたものと同じ「その他」フィールドがあります。返されたstateidのseqid値は、ファイルのアクセスおよび拒否ビットが変更されていない状況でも、インクリメントする必要があります(セクション9.1.4)。

9.12. Short and Long Leases
9.12. 短期および長期リース

When determining the time period for the server lease, the usual lease trade-offs apply. Short leases are good for fast server recovery at a cost of increased RENEW or READ (with zero length) requests. Longer leases are certainly kinder and gentler to servers trying to handle very large numbers of clients. The number of RENEW requests drops in proportion to the lease time. The disadvantages of long leases are slower recovery after server failure (the server must wait for the leases to expire and the grace period to elapse before granting new lock requests) and increased file contention (if the client fails to transmit an unlock request, then the server must wait for lease expiration before granting new locks).

サーバーリースの期間を決定するときは、通常のリーストレードオフが適用されます。短いリースは、RENEWまたはREAD(長さが0の)要求の増加を犠牲にして、サーバーの高速回復に適しています。リースが長いほど、非常に多くのクライアントを処理しようとするサーバーにとって、より親切で穏やかになります。 RENEW要求の数は、リース時間に比例して減少します。長いリースの欠点は、サーバー障害後の回復が遅くなることです(サーバーは、リースが期限切れになり、猶予期間が経過するまで待機してから新しいロック要求を許可する必要があります)、ファイルの競合が増加します(クライアントがロック解除要求の送信に失敗した場合、サーバーは、新しいロックを許可する前にリースの期限切れを待つ必要があります)。

Long leases are usable if the server is able to store lease state in non-volatile memory. Upon recovery, the server can reconstruct the lease state from its non-volatile memory and continue operation with its clients, and therefore long leases would not be an issue.


9.13. Clocks, Propagation Delay, and Calculating Lease Expiration
9.13. クロック、伝搬遅延、およびリースの有効期限の計算

To avoid the need for synchronized clocks, lease times are granted by the server as a time delta. However, there is a requirement that the client and server clocks do not drift excessively over the duration of the lock. There is also the issue of propagation delay across the network -- which could easily be several hundred milliseconds -- as well as the possibility that requests will be lost and need to be retransmitted.


To take propagation delay into account, the client should subtract it from lease times (e.g., if the client estimates the one-way propagation delay as 200 msec, then it can assume that the lease is already 200 msec old when it gets it). In addition, it will take another 200 msec to get a response back to the server. So the client must send a lock renewal or write data back to the server 400 msec before the lease would expire.


The server's lease period configuration should take into account the network distance of the clients that will be accessing the server's resources. It is expected that the lease period will take into account the network propagation delays and other network delay factors for the client population. Since the protocol does not allow for an automatic method to determine an appropriate lease period, the server's administrator may have to tune the lease period.


9.14. Migration, Replication, and State
9.14. 移行、複製、および状態

When responsibility for handling a given file system is transferred to a new server (migration) or the client chooses to use an alternative server (e.g., in response to server unresponsiveness) in the context of file system replication, the appropriate handling of state shared between the client and server (i.e., locks, leases, stateids, and client IDs) is as described below. The handling differs between migration and replication. For a related discussion of file server state and recovery of same, see the subsections of Section 9.6.


In cases in which one server is expected to accept opaque values from the client that originated from another server, the servers SHOULD encode the opaque values in big-endian byte order. If this is done, the new server will be able to parse values like stateids, directory cookies, filehandles, etc. even if their native byte order is different from that of other servers cooperating in the replication and migration of the file system.


9.14.1. Migration and State
9.14.1. 移行と状態

In the case of migration, the servers involved in the migration of a file system SHOULD transfer all server state from the original server to the new server. This must be done in a way that is transparent to the client. This state transfer will ease the client's transition when a file system migration occurs. If the servers are successful in transferring all state, the client will continue to use stateids assigned by the original server. Therefore, the new server must recognize these stateids as valid. This holds true for the client ID as well. Since responsibility for an entire file system is transferred with a migration event, there is no possibility that conflicts will arise on the new server as a result of the transfer of locks.


As part of the transfer of information between servers, leases would be transferred as well. The leases being transferred to the new server will typically have a different expiration time from those for the same client, previously on the old server. To maintain the property that all leases on a given server for a given client expire at the same time, the server should advance the expiration time to the later of the leases being transferred or the leases already present. This allows the client to maintain lease renewal of both classes without special effort.


The servers may choose not to transfer the state information upon migration. However, this choice is discouraged. In this case, when the client presents state information from the original server (e.g., in a RENEW operation or a READ operation of zero length), the client must be prepared to receive either NFS4ERR_STALE_CLIENTID or NFS4ERR_STALE_STATEID from the new server. The client should then recover its state information as it normally would in response to a server failure. The new server must take care to allow for the recovery of state information as it would in the event of server restart.


A client SHOULD re-establish new callback information with the new server as soon as possible, according to sequences described in Sections 16.33 and 16.34. This ensures that server operations are not blocked by the inability to recall delegations.


9.14.2. Replication and State
9.14.2. レプリケーションと状態

Since client switch-over in the case of replication is not under server control, the handling of state is different. In this case, leases, stateids, and client IDs do not have validity across a transition from one server to another. The client must re-establish its locks on the new server. This can be compared to the re-establishment of locks by means of reclaim-type requests after a server reboot. The difference is that the server has no provision to distinguish requests reclaiming locks from those obtaining new locks or to defer the latter. Thus, a client re-establishing a lock on the new server (by means of a LOCK or OPEN request), may have the requests denied due to a conflicting lock. Since replication is intended for read-only use of file systems, such denial of locks should not pose large difficulties in practice. When an attempt to re-establish a lock on a new server is denied, the client should treat the situation as if its original lock had been revoked.


9.14.3. Notification of Migrated Lease
9.14.3. 移行したリースの通知

In the case of lease renewal, the client may not be submitting requests for a file system that has been migrated to another server. This can occur because of the implicit lease renewal mechanism. The client renews leases for all file systems when submitting a request to any one file system at the server.


In order for the client to schedule renewal of leases that may have been relocated to the new server, the client must find out about lease relocation before those leases expire. To accomplish this, all operations that implicitly renew leases for a client (such as OPEN, CLOSE, READ, WRITE, RENEW, LOCK, and others) will return the error NFS4ERR_LEASE_MOVED if responsibility for any of the leases to be renewed has been transferred to a new server. This condition will continue until the client receives an NFS4ERR_MOVED error and the server receives the subsequent GETATTR(fs_locations) for an access to each file system for which a lease has been moved to a new server. By convention, the compound including the GETATTR(fs_locations) SHOULD append a RENEW operation to permit the server to identify the client doing the access.


Upon receiving the NFS4ERR_LEASE_MOVED error, a client that supports file system migration MUST probe all file systems from that server on which it holds open state. Once the client has successfully probed all those file systems that are migrated, the server MUST resume normal handling of stateful requests from that client.


In order to support legacy clients that do not handle the NFS4ERR_LEASE_MOVED error correctly, the server SHOULD time out after a wait of at least two lease periods, at which time it will resume normal handling of stateful requests from all clients. If a client attempts to access the migrated files, the server MUST reply with NFS4ERR_MOVED.


When the client receives an NFS4ERR_MOVED error, the client can follow the normal process to obtain the new server information (through the fs_locations attribute) and perform renewal of those leases on the new server. If the server has not had state transferred to it transparently, the client will receive either NFS4ERR_STALE_CLIENTID or NFS4ERR_STALE_STATEID from the new server, as described above. The client can then recover state information as it does in the event of server failure.


9.14.4. Migration and the lease_time Attribute
9.14.4. 移行とlease_time属性

In order that the client may appropriately manage its leases in the case of migration, the destination server must establish proper values for the lease_time attribute.


When state is transferred transparently, that state should include the correct value of the lease_time attribute. The lease_time attribute on the destination server must never be less than that on the source since this would result in premature expiration of leases granted by the source server. Upon migration, in which state is transferred transparently, the client is under no obligation to refetch the lease_time attribute and may continue to use the value previously fetched (on the source server).


If state has not been transferred transparently (i.e., the client sees a real or simulated server reboot), the client should fetch the value of lease_time on the new (i.e., destination) server and use it for subsequent locking requests. However, the server must respect a grace period at least as long as the lease_time on the source server, in order to ensure that clients have ample time to reclaim their locks before potentially conflicting non-reclaimed locks are granted. The means by which the new server obtains the value of lease_time on the old server is left to the server implementations. It is not specified by the NFSv4 protocol.

状態が透過的に転送されなかった場合(つまり、クライアントが実際のサーバーまたは再起動されたサーバーの再起動を確認した場合)、クライアントは新しい(つまり、宛先)サーバーのlease_timeの値をフェッチし、それを後続のロック要求に使用する必要があります。ただし、サーバーは、少なくともソースサーバーのlease_timeの間は猶予期間を尊重する必要があります。これにより、競合する可能性のある非再利用ロックが許可される前に、クライアントがロックを再利用する十分な時間を確保できます。新しいサーバーが古いサーバーのlease_timeの値を取得する方法は、サーバーの実装に任されています。 NFSv4プロトコルでは指定されていません。

10. Client-Side Caching
10. クライアント側のキャッシュ

Client-side caching of data, file attributes, and filenames is essential to providing good performance with the NFS protocol. Providing distributed cache coherence is a difficult problem, and previous versions of the NFS protocol have not attempted it. Instead, several NFS client implementation techniques have been used to reduce the problems that a lack of coherence poses for users. These techniques have not been clearly defined by earlier protocol specifications, and it is often unclear what is valid or invalid client behavior.


The NFSv4 protocol uses many techniques similar to those that have been used in previous protocol versions. The NFSv4 protocol does not provide distributed cache coherence. However, it defines a more limited set of caching guarantees to allow locks and share reservations to be used without destructive interference from client-side caching.

NFSv4プロトコルは、以前のバージョンのプロトコルで使用されていたものと同様の多くの手法を使用します。 NFSv4プロトコルは、分散キャッシュの一貫性を提供しません。ただし、クライアント側のキャッシングによる破壊的な干渉なしにロックと共有の予約を使用できるように、より限定的なキャッシング保証のセットを定義しています。

In addition, the NFSv4 protocol introduces a delegation mechanism that allows many decisions normally made by the server to be made locally by clients. This mechanism provides efficient support of the common cases where sharing is infrequent or where sharing is read-only.


10.1. Performance Challenges for Client-Side Caching
10.1. クライアント側キャッシュのパフォーマンスの課題

Caching techniques used in previous versions of the NFS protocol have been successful in providing good performance. However, several scalability challenges can arise when those techniques are used with very large numbers of clients. This is particularly true when clients are geographically distributed, which classically increases the latency for cache revalidation requests.


The previous versions of the NFS protocol repeat their file data cache validation requests at the time the file is opened. This behavior can have serious performance drawbacks. A common case is one in which a file is only accessed by a single client. Therefore, sharing is infrequent.


In this case, repeated reference to the server to find that no conflicts exist is expensive. A better option with regards to performance is to allow a client that repeatedly opens a file to do so without reference to the server. This is done until potentially conflicting operations from another client actually occur.


A similar situation arises in connection with file locking. Sending file lock and unlock requests to the server as well as the READ and WRITE requests necessary to make data caching consistent with the locking semantics (see Section 10.3.2) can severely limit performance. When locking is used to provide protection against infrequent conflicts, a large penalty is incurred. This penalty may discourage the use of file locking by applications.


The NFSv4 protocol provides more aggressive caching strategies with the following design goals:


o Compatibility with a large range of server semantics.

o 幅広いサーバーセマンティクスとの互換性。

o Providing the same caching benefits as previous versions of the NFS protocol when unable to provide the more aggressive model.

o より積極的なモデルを提供できない場合、NFSプロトコルの以前のバージョンと同じキャッシュの利点を提供します。

o Organizing requirements for aggressive caching so that a large portion of the benefit can be obtained even when not all of the requirements can be met.

o アグレッシブキャッシングの要件を整理して、要件のすべてが満たされなくても、メリットの大部分を獲得できるようにする。

The appropriate requirements for the server are discussed in later sections, in which specific forms of caching are covered (see Section 10.4).


10.2. Delegation and Callbacks
10.2. 委任とコールバック

Recallable delegation of server responsibilities for a file to a client improves performance by avoiding repeated requests to the server in the absence of inter-client conflict. With the use of a "callback" RPC from server to client, a server recalls delegated responsibilities when another client engages in the sharing of a delegated file.


A delegation is passed from the server to the client, specifying the object of the delegation and the type of delegation. There are different types of delegations, but each type contains a stateid to be used to represent the delegation when performing operations that depend on the delegation. This stateid is similar to those associated with locks and share reservations but differs in that the stateid for a delegation is associated with a client ID and may be used on behalf of all the open-owners for the given client. A delegation is made to the client as a whole and not to any specific process or thread of control within it.


Because callback RPCs may not work in all environments (due to firewalls, for example), correct protocol operation does not depend on them. Preliminary testing of callback functionality by means of a CB_NULL procedure determines whether callbacks can be supported. The CB_NULL procedure checks the continuity of the callback path. A server makes a preliminary assessment of callback availability to a given client and avoids delegating responsibilities until it has determined that callbacks are supported. Because the granting of a delegation is always conditional upon the absence of conflicting access, clients must not assume that a delegation will be granted, and they must always be prepared for OPENs to be processed without any delegations being granted.

コールバックRPCはすべての環境(ファイアウォールなど)で機能しない場合があるため、正しいプロトコル操作はそれらに依存しません。 CB_NULLプロシージャを使用したコールバック機能の予備テストにより、コールバックをサポートできるかどうかが決まります。 CB_NULLプロシージャは、コールバックパスの連続性をチェックします。サーバーは、指定されたクライアントへのコールバックの可用性を事前に評価し、コールバックがサポートされていると判断するまで責任の委任を回避します。委任の付与は常にアクセスの競合がないことを条件としているため、クライアントは委任が付与されることを想定してはならず、委任が付与されずにOPENが処理されるように常に準備しておく必要があります。

Once granted, a delegation behaves in most ways like a lock. There is an associated lease that is subject to renewal, together with all of the other leases held by that client.


Unlike locks, an operation by a second client to a delegated file will cause the server to recall a delegation through a callback.


On recall, the client holding the delegation must flush modified state (such as modified data) to the server and return the delegation. The conflicting request will not be acted on until the recall is complete. The recall is considered complete when the client returns the delegation or the server times out its wait for the delegation to be returned and revokes the delegation as a result of the timeout. In the interim, the server will either delay responding to conflicting requests or respond to them with NFS4ERR_DELAY. Following the resolution of the recall, the server has the information necessary to grant or deny the second client's request.


At the time the client receives a delegation recall, it may have substantial state that needs to be flushed to the server. Therefore, the server should allow sufficient time for the delegation to be returned since it may involve numerous RPCs to the server. If the server is able to determine that the client is diligently flushing state to the server as a result of the recall, the server MAY extend the usual time allowed for a recall. However, the time allowed for recall completion should not be unbounded.


An example of this is when responsibility to mediate opens on a given file is delegated to a client (see Section 10.4). The server will not know what opens are in effect on the client. Without this knowledge, the server will be unable to determine if the access and deny state for the file allows any particular open until the delegation for the file has been returned.


A client failure or a network partition can result in failure to respond to a recall callback. In this case, the server will revoke the delegation; this in turn will render useless any modified state still on the client.


Clients need to be aware that server implementers may enforce practical limitations on the number of delegations issued. Further, as there is no way to determine which delegations to revoke, the server is allowed to revoke any. If the server is implemented to revoke another delegation held by that client, then the client may be able to determine that a limit has been reached because each new delegation request results in a revoke. The client could then determine which delegations it may not need and preemptively release them.


10.2.1. Delegation Recovery
10.2.1. 委任の回復

There are three situations that delegation recovery must deal with:


o Client reboot or restart

o クライアントの再起動または再起動

o Server reboot or restart (see Section

o サーバーの再起動または再起動(セクション9.6.3.1を参照)

o Network partition (full or callback-only)

o ネットワークパーティション(フルまたはコールバックのみ)

In the event that the client reboots or restarts, the confirmation of a SETCLIENTID done with an nfs_client_id4 with a new verifier4 value will result in the release of byte-range locks and share reservations. Delegations, however, may be treated a bit differently.


There will be situations in which delegations will need to be re-established after a client reboots or restarts. The reason for this is the client may have file data stored locally and this data was associated with the previously held delegations. The client will need to re-establish the appropriate file state on the server.


To allow for this type of client recovery, the server MAY allow delegations to be retained after other sorts of locks are released. This implies that requests from other clients that conflict with these delegations will need to wait. Because the normal recall process may require significant time for the client to flush changed state to the server, other clients need to be prepared for delays that occur because of a conflicting delegation. In order to give clients a chance to get through the reboot process -- during which leases will not be renewed -- the server MAY extend the period for delegation recovery beyond the typical lease expiration period. For open delegations, such delegations that are not released are reclaimed using OPEN with a claim type of CLAIM_DELEGATE_PREV. (See Sections 10.5 and 16.16 for discussions of open delegation and the details of OPEN, respectively.)

このタイプのクライアント回復を可能にするために、サーバーは、他の種類のロックが解放された後に委任が保持されることを許可する場合があります。これは、これらの委任と競合する他のクライアントからの要求は待機する必要があることを意味します。通常の再呼び出しプロセスでは、クライアントが変更された状態をサーバーにフラッシュするのにかなりの時間がかかる場合があるため、他のクライアントは、委任の競合が原因で発生する遅延に備える必要があります。クライアントが再起動プロセス(リースが更新されない期間)を通過する機会を提供するために、サーバーは委任回復の期間を通常のリースの有効期限を超えて延長できます(MAY)。オープンな委任の場合、解放されないそのような委任は、クレームタイプがCLAIM_DELEGATE_PREVのOPENを使用して再利用されます。 (オープン委任とOPENの詳細については、それぞれセクション10.5と16.16を参照してください。)

A server MAY support a claim type of CLAIM_DELEGATE_PREV, but if it does, it MUST NOT remove delegations upon SETCLIENTID_CONFIRM and instead MUST make them available for client reclaim using CLAIM_DELEGATE_PREV. The server MUST NOT remove the delegations until either the client does a DELEGPURGE or one lease period has elapsed from the time -- whichever is later -- of the SETCLIENTID_CONFIRM or the last successful CLAIM_DELEGATE_PREV reclaim.

サーバーはクレームタイプCLAIM_DELEGATE_PREVをサポートしてもかまいませんが、サポートする場合は、SETCLIENTID_CONFIRMで委任を削除してはならず、CLAIM_DELEGATE_PREVを使用してクライアントが再利用できるようにする必要があります。サーバーは、クライアントがDELEGPURGEを実行するか、SETCLIENTID_CONFIRMまたは最後に成功したCLAIM_DELEGATE_PREVの再利用の時間(どちらか遅い方)から1つのリース期間が経過するまで、委任を削除してはなりません(MUST NOT)。

Note that the requirement stated above is not meant to imply that, when the server is no longer obliged, as required above, to retain delegation information, it should necessarily dispose of it. Some specific cases are:


o When the period is terminated by the occurrence of DELEGPURGE, deletion of unreclaimed delegations is appropriate and desirable.

o DELEGPURGEの発生により期間が終了する場合は、未回収の委任を削除することが適切で望ましい方法です。

o When the period is terminated by a lease period elapsing without a successful CLAIM_DELEGATE_PREV reclaim, and that situation appears to be the result of a network partition (i.e., lease expiration has occurred), a server's lease expiration approach, possibly including the use of courtesy locks, would normally provide for the retention of unreclaimed delegations. Even in the event that lease cancellation occurs, such delegation should be reclaimed using CLAIM_DELEGATE_PREV as part of network partition recovery.

o CLAIM_DELEGATE_PREVの再利用が成功せずに経過するリース期間によって期間が終了し、その状況がネットワークパーティションの結果であると思われる場合(つまり、リースの期限切れが発生した場合)、サーバーのリース期限切れアプローチ(礼儀ロックの使用を含む) 、通常、未回収の委任の保持を提供します。リースのキャンセルが発生した場合でも、CLAIM_DELEGATE_PREVをネットワークパーティションの回復の一部として使用して、このような委任を取り戻す必要があります。

o When the period of non-communicating is followed by a client reboot, unreclaimed delegations should also be reclaimable by use of CLAIM_DELEGATE_PREV as part of client reboot recovery.

o 非通信の期間の後にクライアントの再起動が続く場合、クライアントの再起動の回復の一部としてCLAIM_DELEGATE_PREVを使用することにより、再利用されていない委任も再利用できるはずです。

o When the period is terminated by a lease period elapsing without a successful CLAIM_DELEGATE_PREV reclaim, and lease renewal is occurring, the server may well conclude that unreclaimed delegations have been abandoned and consider the situation as one in which an implied DELEGPURGE should be assumed.

o CLAIM_DELEGATE_PREVの再利用が成功せずにリース期間が経過して期間が終了し、リースの更新が行われている場合、サーバーは、再利用されていない委任が放棄されたと結論付け、暗黙のDELEGPURGEが想定される状況と見なす可能性があります。

A server that supports a claim type of CLAIM_DELEGATE_PREV MUST support the DELEGPURGE operation, and similarly, a server that supports DELEGPURGE MUST support CLAIM_DELEGATE_PREV. A server that does not support CLAIM_DELEGATE_PREV MUST return NFS4ERR_NOTSUPP if the client attempts to use that feature or performs a DELEGPURGE operation.

CLAIM_DELEGATE_PREVのクレームタイプをサポートするサーバーは、DELEGPURGE操作をサポートする必要があり、同様に、DELEGPURGEをサポートするサーバーは、CLAIM_DELEGATE_PREVをサポートする必要があります。 CLAIM_DELEGATE_PREVをサポートしないサーバーは、クライアントがその機能を使用するか、DELEGPURGE操作を実行する場合、NFS4ERR_NOTSUPPを返さなければなりません(MUST)。

Support for a claim type of CLAIM_DELEGATE_PREV is often referred to as providing for "client-persistent delegations" in that they allow the use of persistent storage on the client to store data written by the client, even across a client restart. It should be noted that, with the optional exception noted below, this feature requires persistent storage to be used on the client and does not add to persistent storage requirements on the server.


One good way to think about client-persistent delegations is that for the most part, they function like "courtesy locks", with special semantic adjustments to allow them to be retained across a client restart, which cause all other sorts of locks to be freed. Such locks are generally not retained across a server restart. The one exception is the case of simultaneous failure of the client and server and is discussed below.

クライアント永続的な委任について考える良い方法の1つは、ほとんどの場合、「礼儀ロック」のように機能し、特別なセマンティック調整によってクライアントの再起動後も保持できるようにすることです。これにより、他のすべての種類のロックが解放されます。 。このようなロックは通常、サーバーを再起動しても保持されません。 1つの例外は、クライアントとサーバーの同時障害の場合であり、以下で説明します。

When the server indicates support of CLAIM_DELEGATE_PREV (implicitly) by returning NFS_OK to DELEGPURGE, a client with a write delegation can use write-back caching for data to be written to the server, deferring the write-back until such time as the delegation is recalled, possibly after intervening client restarts. Similarly, when the server indicates support of CLAIM_DELEGATE_PREV, a client with a read delegation and an open-for-write subordinate to that delegation may be sure of the integrity of its persistently cached copy of the file after a client restart without specific verification of the change attribute.

サーバーがCLAIM_DELEGATE_PREVのサポートを(暗黙的に)示し、NFS_OKをDELEGPURGEに戻すと、書き込み委任を持つクライアントは、サーバーに書き込まれるデータにライトバックキャッシュを使用して、委任がリコールされるまでライトバックを延期できます。 、おそらく介在するクライアントの再起動後。同様に、サーバーがCLAIM_DELEGATE_PREVのサポートを示している場合、読み取り委任とその委任に従属する書き込み用にオープンされたクライアントは、クライアントを再起動した後、永続的にキャッシュされたファイルのコピーの完全性を確認できます。属性を変更します。

When the server reboots or restarts, delegations are reclaimed (using the OPEN operation with CLAIM_PREVIOUS) in a similar fashion to byte-range locks and share reservations. However, there is a slight semantic difference. In the normal case, if the server decides that a delegation should not be granted, it performs the requested action (e.g., OPEN) without granting any delegation. For reclaim, the server grants the delegation, but a special designation is applied so that the client treats the delegation as having been granted but recalled by the server. Because of this, the client has the duty to write all modified state to the server and then return the delegation. This process of handling delegation reclaim reconciles three principles of the NFSv4 protocol:


o Upon reclaim, a client claiming resources assigned to it by an earlier server instance must be granted those resources.

o 再利用時に、以前のサーバーインスタンスによって割り当てられたリソースを要求するクライアントには、それらのリソースを付与する必要があります。

o The server has unquestionable authority to determine whether delegations are to be granted and, once granted, whether they are to be continued.

o サーバーには、委任を許可するかどうかを決定し、一度許可すると、続行するかどうかを決定する疑いのない権限があります。

o The use of callbacks is not to be depended upon until the client has proven its ability to receive them.

o コールバックの使用は、クライアントがそれらを受信する能力を証明するまでは依存しません。

When a client has more than a single open associated with a delegation, state for those additional opens can be established using OPEN operations of type CLAIM_DELEGATE_CUR. When these are used to establish opens associated with reclaimed delegations, the server MUST allow them when made within the grace period.


Situations in which there is a series of client and server restarts where there is no restart of both at the same time are dealt with via a combination of CLAIM_DELEGATE_PREV and CLAIM_PREVIOUS reclaim cycles. Persistent storage is needed only on the client. For each server failure, a CLAIM_PREVIOUS reclaim cycle is done, while for each client restart, a CLAIM_DELEGATE_PREV reclaim cycle is done.


To deal with the possibility of simultaneous failure of client and server (e.g., a data center power outage), the server MAY persistently store delegation information so that it can respond to a CLAIM_DELEGATE_PREV reclaim request that it receives from a restarting client. This is the one case in which persistent delegation state can be retained across a server restart. A server is not required to store this information, but if it does do so, it should do so for write delegations and for read delegations, during the pendency of which (across multiple client and/or server instances), some open-for-write was done as part of delegation. When the space to persistently record such information is limited, the server should recall delegations in this class in preference to keeping them active without persistent storage recording.


When a network partition occurs, delegations are subject to freeing by the server when the lease renewal period expires. This is similar to the behavior for locks and share reservations, and as for locks and share reservations, it may be modified by support for "courtesy locks" in which locks are not freed in the absence of a conflicting lock request. Whereas for locks and share reservations the freeing of locks will occur immediately upon the appearance of a conflicting request, for delegations, the server MAY institute a period during which conflicting requests are held off. Eventually, the occurrence of a conflicting request from another client will cause revocation of the delegation.


A loss of the callback path (e.g., by a later network configuration change) will have a similar effect in that it can also result in revocation of a delegation. A recall request will fail, and revocation of the delegation will result.


A client normally finds out about revocation of a delegation when it uses a stateid associated with a delegation and receives one of the errors NFS4ERR_EXPIRED, NFS4ERR_BAD_STATEID, or NFS4ERR_ADMIN_REVOKED (NFS4ERR_EXPIRED indicates that all lock state associated with the client has been lost). It also may find out about delegation revocation after a client reboot when it attempts to reclaim a delegation and receives NFS4ERR_EXPIRED. Note that in the case of a revoked OPEN_DELEGATE_WRITE delegation, there are issues because data may have been modified by the client whose delegation is revoked and, separately, by other clients. See Section 10.5.1 for a discussion of such issues. Note also that when delegations are revoked, information about the revoked delegation will be written by the server to stable storage (as described in Section 9.6). This is done to deal with the case in which a server reboots after revoking a delegation but before the client holding the revoked delegation is notified about the revocation.

クライアントは通常、委任に関連付けられた状態IDを使用し、エラーNFS4ERR_EXPIRED、NFS4ERR_BAD_STATEID、またはNFS4ERR_ADMIN_REVOKED(NFS4ERR_EXPIREDは、クライアントに関連付けられたすべてのロック状態が失われたことを示します)のいずれかを受け取ると、委任の取り消しについて調べます。また、クライアントの再起動後に委任を再利用しようとしてNFS4ERR_EXPIREDを受け取ったときに、委任の取り消しについても知ることができます。 OPEN_DELEGATE_WRITE委任が取り消された場合は、委任が取り消されたクライアントによって、また他のクライアントによって個別にデータが変更された可能性があるため、問題が発生することに注意してください。このような問題については、セクション10.5.1を参照してください。委任が取り消されると、取り消された委任に関する情報がサーバーによって安定したストレージに書き込まれることにも注意してください(セクション9.6で説明)。これは、委任を取り消した後で、取り消された委任を保持しているクライアントに取り消しが通知される前にサーバーが再起動する場合に対処するために行われます。

Note that when there is a loss of a delegation, due to a network partition in which all locks associated with the lease are lost, the client will also receive the error NFS4ERR_EXPIRED. This case can be distinguished from other situations in which delegations are revoked by seeing that the associated clientid becomes invalid so that NFS4ERR_STALE_CLIENTID is returned when it is used.


When NFS4ERR_EXPIRED is returned, the server MAY retain information about the delegations held by the client, deleting those that are invalidated by a conflicting request. Retaining such information will allow the client to recover all non-invalidated delegations using the claim type CLAIM_DELEGATE_PREV, once the SETCLIENTID_CONFIRM is done to recover. Attempted recovery of a delegation that the client has no record of, typically because they were invalidated by conflicting requests, will result in the error NFS4ERR_BAD_RECLAIM. Once a reclaim is attempted for all delegations that the client held, it SHOULD do a DELEGPURGE to allow any remaining server delegation information to be freed.


10.3. Data Caching
10.3. データキャッシング

When applications share access to a set of files, they need to be implemented so as to take account of the possibility of conflicting access by another application. This is true whether the applications in question execute on different clients or reside on the same client.


Share reservations and byte-range locks are the facilities the NFSv4 protocol provides to allow applications to coordinate access by providing mutual exclusion facilities. The NFSv4 protocol's data caching must be implemented such that it does not invalidate the assumptions that those using these facilities depend upon.

共有予約とバイト範囲ロックは、NFSv4プロトコルが提供する機能であり、相互排除機能を提供することにより、アプリケーションがアクセスを調整できるようにします。 NFSv4プロトコルのデータキャッシングは、これらの機能を使用するユーザーが依存する前提を無効にしないように実装する必要があります。

10.3.1. Data Caching and OPENs
10.3.1. データキャッシングとOPEN

In order to avoid invalidating the sharing assumptions that applications rely on, NFSv4 clients should not provide cached data to applications or modify it on behalf of an application when it would not be valid to obtain or modify that same data via a READ or WRITE operation.


Furthermore, in the absence of open delegation (see Section 10.4), two additional rules apply. Note that these rules are obeyed in practice by many NFSv2 and NFSv3 clients.


o First, cached data present on a client must be revalidated after doing an OPEN. Revalidating means that the client fetches the change attribute from the server, compares it with the cached change attribute, and, if different, declares the cached data (as well as the cached attributes) as invalid. This is to ensure that the data for the OPENed file is still correctly reflected in the client's cache. This validation must be done at least when the client's OPEN operation includes DENY=WRITE or BOTH, thus terminating a period in which other clients may have had the opportunity to open the file with WRITE access. Clients may choose to do the revalidation more often (such as at OPENs specifying DENY=NONE) to parallel the NFSv3 protocol's practice for the benefit of users assuming this degree of cache revalidation.

o まず、クライアントに存在するキャッシュされたデータは、OPENの実行後に再検証する必要があります。再検証とは、クライアントがサーバーから変更属性をフェッチし、それをキャッシュされた変更属性と比較し、異なる場合は、キャッシュされたデータ(およびキャッシュされた属性)を無効として宣言することを意味します。これは、OPENedファイルのデータがクライアントのキャッシュに正しく反映されるようにするためです。この検証は、少なくともクライアントのOPEN操作にDENY = WRITEまたはBOTHが含まれている場合に実行する必要があります。これにより、他のクライアントがWRITEアクセスでファイルを開く機会があった可能性がある期間が終了します。クライアントは、より頻繁に再検証を行うこと(OPENでDENY = NONEを指定するなど)を選択して、この程度のキャッシュの再検証を想定しているユーザーの利益のために、NFSv3プロトコルの実践に対応することができます。

Since the change attribute is updated for data and metadata modifications, some client implementers may be tempted to use the time_modify attribute and not the change attribute to validate cached data, so that metadata changes do not spuriously invalidate clean data. The implementer is cautioned against this approach. The change attribute is guaranteed to change for each update to the file, whereas time_modify is guaranteed to change only at the granularity of the time_delta attribute. Use by the client's data cache validation logic of time_modify and not the change attribute runs the risk of the client incorrectly marking stale data as valid.

変更属性はデータとメタデータの変更のために更新されるため、一部のクライアント実装者は変更属性ではなくtime_modify属性を使用して、キャッシュされたデータを検証するように誘惑され、メタデータの変更がクリーンなデータを誤って無効にすることがなくなります。実装者は、このアプローチに対して警告されます。 change属性は、ファイルの更新ごとに変更されることが保証されていますが、time_modifyは、time_delta属性の粒度でのみ変更されることが保証されています。クライアントのデータキャッシュ検証ロジックでtime_modifyを使用し、change属性では使用しないと、クライアントが古いデータを有効として誤ってマークするリスクがあります。

o Second, modified data must be flushed to the server before closing a file OPENed for write. This is complementary to the first rule. If the data is not flushed at CLOSE, the revalidation done after the client OPENs a file is unable to achieve its purpose. The other aspect to flushing the data before close is that the data must be committed to stable storage, at the server, before the CLOSE operation is requested by the client. In the case of a server reboot or restart and a CLOSEd file, it may not be possible to retransmit the data to be written to the file -- hence, this requirement.

o 第2に、書き込み用にOPENされたファイルを閉じる前に、変更されたデータをサーバーにフラッシュする必要があります。これは最初のルールを補足するものです。データがCLOSEでフラッシュされない場合、クライアントがファイルをOPENした後に行われる再検証は、その目的を達成できません。閉じる前にデータをフラッシュするもう1つの側面は、クライアントがCLOSE操作を要求する前に、サーバーでデータを安定したストレージにコミットする必要があることです。サーバーの再起動または再起動とCLOSEdファイルの場合、ファイルに書き込まれるデータを再送信できない可能性があるため、この要件が発生します。

10.3.2. Data Caching and File Locking
10.3.2. データのキャッシュとファイルのロック

For those applications that choose to use file locking instead of share reservations to exclude inconsistent file access, there is an analogous set of constraints that apply to client-side data caching. These rules are effective only if the file locking is used in a way that matches in an equivalent way the actual READ and WRITE operations executed. This is as opposed to file locking that is based on pure convention. For example, it is possible to manipulate a two-megabyte file by dividing the file into two one-megabyte regions and protecting access to the two regions by file locks on bytes zero and one. A lock for write on byte zero of the file would represent the right to do READ and WRITE operations on the first region. A lock for write on byte one of the file would represent the right to do READ and WRITE operations on the second region. As long as all applications manipulating the file obey this convention, they will work on a local file system. However, they may not work with the NFSv4 protocol unless clients refrain from data caching.


The rules for data caching in the file locking environment are:


o First, when a client obtains a file lock for a particular region, the data cache corresponding to that region (if any cached data exists) must be revalidated. If the change attribute indicates that the file may have been updated since the cached data was obtained, the client must flush or invalidate the cached data for the newly locked region. A client might choose to invalidate all of the non-modified cached data that it has for the file, but the only requirement for correct operation is to invalidate all of the data in the newly locked region.

o まず、クライアントが特定の領域のファイルロックを取得すると、その領域に対応するデータキャッシュ(キャッシュされたデータが存在する場合)を再検証する必要があります。変更された属性が、キャッシュされたデータの取得後にファイルが更新された可能性があることを示している場合、クライアントは、新しくロックされた領域のキャッシュされたデータをフラッシュまたは無効にする必要があります。クライアントは、ファイルにある変更されていないキャッシュデータをすべて無効にすることを選択する場合がありますが、正しく動作するための唯一の要件は、新しくロックされた領域のすべてのデータを無効にすることです。

o Second, before releasing a write lock for a region, all modified data for that region must be flushed to the server. The modified data must also be written to stable storage.

o 次に、リージョンの書き込みロックを解放する前に、そのリージョンのすべての変更データをサーバーにフラッシュする必要があります。変更されたデータも安定したストレージに書き込む必要があります。

Note that flushing data to the server and the invalidation of cached data must reflect the actual byte ranges locked or unlocked. Rounding these up or down to reflect client cache block boundaries will cause problems if not carefully done. For example, writing a modified block when only half of that block is within an area being unlocked may cause invalid modification to the region outside the unlocked area. This, in turn, may be part of a region locked by another client. Clients can avoid this situation by synchronously performing portions of WRITE operations that overlap that portion (initial or final) that is not a full block. Similarly, invalidating a locked area that is not an integral number of full buffer blocks would require the client to read one or two partial blocks from the server if the revalidation procedure shows that the data that the client possesses may not be valid.


The data that is written to the server as a prerequisite to the unlocking of a region must be written, at the server, to stable storage. The client may accomplish this either with synchronous writes or by following asynchronous writes with a COMMIT operation. This is required because retransmission of the modified data after a server reboot might conflict with a lock held by another client.


A client implementation may choose to accommodate applications that use byte-range locking in non-standard ways (e.g., using a byte-range lock as a global semaphore) by flushing to the server more data upon a LOCKU than is covered by the locked range. This may include modified data within files other than the one for which the unlocks are being done. In such cases, the client must not interfere with applications whose READs and WRITEs are being done only within the bounds of record locks that the application holds. For example, an application locks a single byte of a file and proceeds to write that single byte. A client that chose to handle a LOCKU by flushing all modified data to the server could validly write that single byte in response to an unrelated unlock. However, it would not be valid to write the entire block in which that single written byte was located since it includes an area that is not locked and might be locked by another client. Client implementations can avoid this problem by dividing files with modified data into those for which all modifications are done to areas covered by an appropriate byte-range lock and those for which there are modifications not covered by a byte-range lock. Any writes done for the former class of files must not include areas not locked and thus not modified on the client.

クライアントの実装は、非標準の方法でバイト範囲ロックを使用するアプリケーション(たとえば、グローバルセマフォとしてバイト範囲ロックを使用する)に対応することを選択できます。 。これには、ロック解除が行われているファイル以外のファイル内の変更されたデータが含まれる場合があります。このような場合、クライアントは、アプリケーションが保持するレコードロックの境界内でのみREADおよびWRITEが実行されるアプリケーションに干渉してはなりません。たとえば、アプリケーションはファイルの1バイトをロックし、その1バイトの書き込みを続行します。変更されたすべてのデータをサーバーにフラッシュすることによってLOCKUを処理することを選択したクライアントは、無関係なロック解除に応答してその1バイトを有効に書き込むことができます。ただし、ロックされていない領域が含まれていて、別のクライアントによってロックされている可能性があるため、その単一の書き込まれたバイトが配置されたブロック全体を書き込むことは無効です。クライアントの実装では、データが変更されたファイルを、適切なバイト範囲ロックでカバーされる領域にすべての変更が加えられるファイルと、バイト範囲ロックでカバーされない変更があるファイルに分割することで、この問題を回避できます。前のクラスのファイルに対して行われた書き込みには、ロックされていない領域が含まれていて、クライアントで変更されていないことが必要です。

10.3.3. Data Caching and Mandatory File Locking
10.3.3. データキャッシングと必須ファイルロック

Client-side data caching needs to respect mandatory file locking when it is in effect. The presence of mandatory file locking for a given file is indicated when the client gets back NFS4ERR_LOCKED from a READ or WRITE on a file it has an appropriate share reservation for. When mandatory locking is in effect for a file, the client must check for an appropriate file lock for data being read or written. If a lock exists for the range being read or written, the client may satisfy the request using the client's validated cache. If an appropriate file lock is not held for the range of the READ or WRITE, the READ or WRITE request must not be satisfied by the client's cache and the request must be sent to the server for processing. When a READ or WRITE request partially overlaps a locked region, the request should be subdivided into multiple pieces with each region (locked or not) treated appropriately.

クライアント側のデータキャッシュは、有効な場合、必須のファイルロックを尊重する必要があります。特定のファイルの必須ファイルロックの存在は、クライアントが適切な共有予約を持っているファイルの読み取りまたは書き込みからNFS4ERR_LOCKEDを取得したときに示されます。ファイルに対して強制ロックが有効になっている場合、クライアントは、読み取りまたは書き込み中のデータに対して適切なファイルロックを確認する必要があります。読み取りまたは書き込みされている範囲にロックが存在する場合、クライアントは、クライアントの検証済みキャッシュを使用して要求を満たすことができます。 READまたはWRITEの範囲で適切なファイルロックが保持されていない場合、READまたはWRITE要求はクライアントのキャッシュによって満たされず、要求はサーバーに送信されて処理される必要があります。 READまたはWRITE要求がロックされた領域と部分的にオーバーラップする場合、要求は複数の部分に分割され、各領域(ロックされているかどうかにかかわらず)が適切に処理されます。

10.3.4. Data Caching and File Identity
10.3.4. データキャッシングとファイルID

When clients cache data, the file data needs to be organized according to the file system object to which the data belongs. For NFSv3 clients, the typical practice has been to assume for the purpose of caching that distinct filehandles represent distinct file system objects. The client then has the choice to organize and maintain the data cache on this basis.

クライアントがデータをキャッシュする場合、ファイルデータは、データが属するファイルシステムオブジェクトに従って編成する必要があります。 NFSv3クライアントの場合、典型的な慣例は、キャッシングの目的で、個別のファイルハンドルが個別のファイルシステムオブジェクトを表すと想定することでした。その後、クライアントは、これに基づいてデータキャッシュを整理および維持することを選択できます。

In the NFSv4 protocol, there is now the possibility of having significant deviations from a "one filehandle per object" model, because a filehandle may be constructed on the basis of the object's pathname. Therefore, clients need a reliable method to determine if two filehandles designate the same file system object. If clients were simply to assume that all distinct filehandles denote distinct objects and proceed to do data caching on this basis, caching inconsistencies would arise between the distinct client-side objects that mapped to the same server-side object.


By providing a method to differentiate filehandles, the NFSv4 protocol alleviates a potential functional regression in comparison with the NFSv3 protocol. Without this method, caching inconsistencies within the same client could occur, and this has not been present in previous versions of the NFS protocol. Note that it is possible to have such inconsistencies with applications executing on multiple clients, but that is not the issue being addressed here.


For the purposes of data caching, the following steps allow an NFSv4 client to determine whether two distinct filehandles denote the same server-side object:


o If GETATTR directed to two filehandles returns different values of the fsid attribute, then the filehandles represent distinct objects.

o 2つのファイルハンドルに向けられたGETATTRがfsid属性の異なる値を返す場合、ファイルハンドルは異なるオブジェクトを表します。

o If GETATTR for any file with an fsid that matches the fsid of the two filehandles in question returns a unique_handles attribute with a value of TRUE, then the two objects are distinct.

o 問題の2つのファイルハンドルのfsidと一致するfsidを持つファイルのGETATTRが値がTRUEのunique_handles属性を返す場合、2つのオブジェクトは異なります。

o If GETATTR directed to the two filehandles does not return the fileid attribute for both of the handles, then it cannot be determined whether the two objects are the same. Therefore, operations that depend on that knowledge (e.g., client-side data caching) cannot be done reliably. Note that if GETATTR does not return the fileid attribute for both filehandles, it will return it for neither of the filehandles, since the fsid for both filehandles is the same.

o 2つのファイルハンドルに向けられたGETATTRが両方のハンドルのfileid属性を返さない場合、2つのオブジェクトが同じかどうかを判断できません。したがって、その知識に依存する操作(クライアント側のデータキャッシュなど)は確実に実行できません。 GETATTRが両方のファイルハンドルのfileid属性を返さない場合、両方のファイルハンドルのfsidが同じであるため、どちらのファイルハンドルにもそれを返します。

o If GETATTR directed to the two filehandles returns different values for the fileid attribute, then they are distinct objects.

o 2つのファイルハンドルに向けられたGETATTRがfileid属性に異なる値を返す場合、それらは異なるオブジェクトです。

o Otherwise, they are the same object.

o それ以外の場合は、同じオブジェクトです。

10.4. Open Delegation
10.4. オープンな委任

When a file is being OPENed, the server may delegate further handling of opens and closes for that file to the opening client. Any such delegation is recallable, since the circumstances that allowed for the delegation are subject to change. In particular, the server may receive a conflicting OPEN from another client; the server must recall the delegation before deciding whether the OPEN from the other client may be granted. Making a delegation is up to the server, and clients should not assume that any particular OPEN either will or will not result in an open delegation. The following is a typical set of conditions that servers might use in deciding whether OPEN should be delegated:


o The client must be able to respond to the server's callback requests. The server will use the CB_NULL procedure for a test of callback ability.

o クライアントは、サーバーのコールバック要求に応答できる必要があります。サーバーは、コールバック機能のテストにCB_NULLプロシージャを使用します。

o The client must have responded properly to previous recalls.

o クライアントは以前のリコールに適切に応答している必要があります。

o There must be no current open conflicting with the requested delegation.

o 現在、要求された委任と競合するオープンオープンがあってはなりません。

o There should be no current delegation that conflicts with the delegation being requested.

o 要求されている委任と競合する現在の委任があってはなりません。

o The probability of future conflicting open requests should be low, based on the recent history of the file.

o ファイルの最近の履歴に基づいて、将来の競合するオープンリクエストの可能性は低くなるはずです。

o The existence of any server-specific semantics of OPEN/CLOSE that would make the required handling incompatible with the prescribed handling that the delegated client would apply (see below).

o 必要な処理を、委任されたクライアントが適用する規定の処理と互換性のないものにする、OPEN / CLOSEのサーバー固有のセマンティクスの存在(以下を参照)。

There are two types of open delegations: OPEN_DELEGATE_READ and OPEN_DELEGATE_WRITE. An OPEN_DELEGATE_READ delegation allows a client to handle, on its own, requests to open a file for reading that do not deny read access to others. It MUST, however, continue to send all requests to open a file for writing to the server. Multiple OPEN_DELEGATE_READ delegations may be outstanding simultaneously and do not conflict. An OPEN_DELEGATE_WRITE delegation allows the client to handle, on its own, all opens. Only one OPEN_DELEGATE_WRITE delegation may exist for a given file at a given time, and it is inconsistent with any OPEN_DELEGATE_READ delegations.

OPEN_DELEGATE_READとOPEN_DELEGATE_WRITEの2つのタイプのオープンな委任があります。 OPEN_DELEGATE_READ委任を使用すると、クライアントは、他のユーザーへの読み取りアクセスを拒否しない読み取り専用のファイルを開く要求を、それ自体で処理できます。ただし、サーバーに書き込むためにファイルを開くためのすべての要求を送信し続ける必要があります。複数のOPEN_DELEGATE_READ委任が同時に未解決であり、競合しない場合があります。 OPEN_DELEGATE_WRITE委任により、クライアントは単独ですべてのオープンを処理できます。特定の時間に特定のファイルに対して存在できるOPEN_DELEGATE_WRITE委任は1つだけであり、OPEN_DELEGATE_READ委任と矛盾します。

When a single client holds an OPEN_DELEGATE_READ delegation, it is assured that no other client may modify the contents or attributes of the file. If more than one client holds an OPEN_DELEGATE_READ delegation, then the contents and attributes of that file are not allowed to change. When a client has an OPEN_DELEGATE_WRITE delegation, it may modify the file data since no other client will be accessing the file's data. The client holding an OPEN_DELEGATE_WRITE delegation may only affect file attributes that are intimately connected with the file data: size, time_modify, and change.

単一のクライアントがOPEN_DELEGATE_READ委任を保持している場合、他のクライアントがファイルの内容または属性を変更できないことが保証されます。複数のクライアントがOPEN_DELEGATE_READ委任を保持している場合、そのファイルの内容と属性は変更できません。クライアントにOPEN_DELEGATE_WRITE委任がある場合、他のクライアントがファイルのデータにアクセスしないため、クライアントはファイルデータを変更する可能性があります。 OPEN_DELEGATE_WRITE委任を保持しているクライアントは、サイズ、time_modify、およびchangeなど、ファイルデータと密接に関連しているファイル属性にのみ影響を与える可能性があります。

When a client has an open delegation, it does not send OPENs or CLOSEs to the server but updates the appropriate status internally. For an OPEN_DELEGATE_READ delegation, opens that cannot be handled locally (opens for write or that deny read access) must be sent to the server.

クライアントにオープンな委任がある場合、クライアントはサーバーにOPENまたはCLOSEを送信しませんが、内部で適切なステータスを更新します。 OPEN_DELEGATE_READ委任の場合、ローカルで処理できないオープン(書き込み用のオープンまたは読み取りアクセスを拒否する)をサーバーに送信する必要があります。

When an open delegation is made, the response to the OPEN contains an open delegation structure that specifies the following:


o the type of delegation (read or write)

o 委任のタイプ(読み取りまたは書き込み)

o space limitation information to control flushing of data on close (OPEN_DELEGATE_WRITE delegation only; see Section 10.4.1)

o クローズ時のデータのフラッシュを制御するスペース制限情報(OPEN_DELEGATE_WRITE委任のみ。セクション10.4.1を参照)

o an nfsace4 specifying read and write permissions

o 読み取りおよび書き込み権限を指定するnfsace4

o a stateid to represent the delegation for READ and WRITE

o READおよびWRITEの委任を表す状態ID

The delegation stateid is separate and distinct from the stateid for the OPEN proper. The standard stateid, unlike the delegation stateid, is associated with a particular open-owner and will continue to be valid after the delegation is recalled and the file remains open.


When a request internal to the client is made to open a file and open delegation is in effect, it will be accepted or rejected solely on the basis of the following conditions. Any requirement for other checks to be made by the delegate should result in open delegation being denied so that the checks can be made by the server itself.


o The access and deny bits for the request and the file, as described in Section 9.9.

o セクション9.9で説明されている、リクエストとファイルのアクセスビットと拒否ビット。

o The read and write permissions, as determined below.

o 以下に示すように、読み取りおよび書き込み権限。

The nfsace4 passed with delegation can be used to avoid frequent ACCESS calls. The permission check should be as follows:


o If the nfsace4 indicates that the open may be done, then it should be granted without reference to the server.

o nfsace4がオープンを実行できることを示している場合は、サーバーを参照せずに許可する必要があります。

o If the nfsace4 indicates that the open may not be done, then an ACCESS request must be sent to the server to obtain the definitive answer.

o nfsace4がオープンが実行されない可能性があることを示している場合、最終的な回答を取得するには、ACCESS要求をサーバーに送信する必要があります。

The server may return an nfsace4 that is more restrictive than the actual ACL of the file. This includes an nfsace4 that specifies denial of all access. Note that some common practices, such as mapping the traditional user "root" to the user "nobody", may make it incorrect to return the actual ACL of the file in the delegation response.


The use of delegation, together with various other forms of caching, creates the possibility that no server authentication will ever be performed for a given user since all of the user's requests might be satisfied locally. Where the client is depending on the server for authentication, the client should be sure authentication occurs for each user by use of the ACCESS operation. This should be the case even if an ACCESS operation would not be required otherwise. As mentioned before, the server may enforce frequent authentication by returning an nfsace4 denying all access with every open delegation.


10.4.1. Open Delegation and Data Caching
10.4.1. オープンな委任とデータキャッシング

OPEN delegation allows much of the message overhead associated with the opening and closing files to be eliminated. An open when an open delegation is in effect does not require that a validation message be sent to the server unless there exists a potential for conflict with the requested share mode. The continued endurance of the "OPEN_DELEGATE_READ delegation" provides a guarantee that no OPEN for write and thus no write has occurred that did not originate from this client. Similarly, when closing a file opened for write and if OPEN_DELEGATE_WRITE delegation is in effect, the data written does not have to be flushed to the server until the open delegation is recalled. The continued endurance of the open delegation provides a guarantee that no open and thus no read or write has been done by another client.

OPEN委任により、ファイルのオープンとクローズに関連するメッセージオーバーヘッドの多くを排除できます。開いている委任が有効なときに開く場合、要求された共有モードとの競合の可能性がない限り、検証メッセージをサーバーに送信する必要はありません。 「OPEN_DELEGATE_READ委任」の継続的な耐久性により、書き込み用のOPENがないため、このクライアントから発生していない書き込みが発生していないことが保証されます。同様に、書き込み用に開いたファイルを閉じるとき、OPEN_DELEGATE_WRITE委任が有効な場合、開いた委任が呼び出されるまで、書き込まれたデータをサーバーにフラッシュする必要はありません。オープンな委任の継続的な耐久性は、他のクライアントによってオープンが行われず、したがって読み取りまたは書き込みが行われないことを保証します。

For the purposes of open delegation, READs and WRITEs done without an OPEN (anonymous and READ bypass stateids) are treated as the functional equivalents of a corresponding type of OPEN. READs and WRITEs done with an anonymous stateid done by another client will force the server to recall an OPEN_DELEGATE_WRITE delegation. A WRITE with an anonymous stateid done by another client will force a recall of OPEN_DELEGATE_READ delegations. The handling of a READ bypass stateid is identical, except that a READ done with a READ bypass stateid will not force a recall of an OPEN_DELEGATE_READ delegation.

オープン委任の目的で、OPENなしで実行されるREADおよびWRITE(匿名およびREADバイパスステートID)は、対応するタイプのOPENと機能的に同等のものとして扱われます。別のクライアントによって行われた匿名状態IDで行われた読み取りと書き込みは、サーバーにOPEN_DELEGATE_WRITE委任を再呼び出しさせます。別のクライアントが匿名の状態IDを使用してWRITEを実行すると、OPEN_DELEGATE_READ委任が強制的に呼び出されます。 READバイパスステートIDの処理は同じですが、READバイパスステートIDを使用して実行されたREADはOPEN_DELEGATE_READ委任の再呼び出しを強制しません。

With delegations, a client is able to avoid writing data to the server when the CLOSE of a file is serviced. The file close system call is the usual point at which the client is notified of a lack of stable storage for the modified file data generated by the application. At the close, file data is written to the server, and through normal accounting the server is able to determine if the available file system space for the data has been exceeded (i.e., the server returns NFS4ERR_NOSPC or NFS4ERR_DQUOT). This accounting includes quotas. The introduction of delegations requires that an alternative method be in place for the same type of communication to occur between client and server.


In the delegation response, the server provides either the limit of the size of the file or the number of modified blocks and associated block size. The server must ensure that the client will be able to flush to the server data of a size equal to that provided in the original delegation. The server must make this assurance for all outstanding delegations. Therefore, the server must be careful in its management of available space for new or modified data, taking into account available file system space and any applicable quotas. The server can recall delegations as a result of managing the available file system space. The client should abide by the server's state space limits for delegations. If the client exceeds the stated limits for the delegation, the server's behavior is undefined.


Based on server conditions, quotas, or available file system space, the server may grant OPEN_DELEGATE_WRITE delegations with very restrictive space limitations. The limitations may be defined in a way that will always force modified data to be flushed to the server on close.


With respect to authentication, flushing modified data to the server after a CLOSE has occurred may be problematic. For example, the user of the application may have logged off the client, and unexpired authentication credentials may not be present. In this case, the client may need to take special care to ensure that local unexpired credentials will in fact be available. One way that this may be accomplished is by tracking the expiration time of credentials and flushing data well in advance of their expiration.


10.4.2. Open Delegation and File Locks
10.4.2. 委任とファイルロックを開く

When a client holds an OPEN_DELEGATE_WRITE delegation, lock operations may be performed locally. This includes those required for mandatory file locking. This can be done since the delegation implies that there can be no conflicting locks. Similarly, all of the revalidations that would normally be associated with obtaining locks and the flushing of data associated with the releasing of locks need not be done.


When a client holds an OPEN_DELEGATE_READ delegation, lock operations are not performed locally. All lock operations, including those requesting non-exclusive locks, are sent to the server for resolution.


10.4.3. Handling of CB_GETATTR
10.4.3. CB_GETATTRの処理

The server needs to employ special handling for a GETATTR where the target is a file that has an OPEN_DELEGATE_WRITE delegation in effect. The reason for this is that the client holding the OPEN_DELEGATE_WRITE delegation may have modified the data, and the server needs to reflect this change to the second client that submitted the GETATTR. Therefore, the client holding the OPEN_DELEGATE_WRITE delegation needs to be interrogated. The server will use the CB_GETATTR operation. The only attributes that the server can reliably query via CB_GETATTR are size and change.


Since CB_GETATTR is being used to satisfy another client's GETATTR request, the server only needs to know if the client holding the delegation has a modified version of the file. If the client's copy of the delegated file is not modified (data or size), the server can satisfy the second client's GETATTR request from the attributes stored locally at the server. If the file is modified, the server only needs to know about this modified state. If the server determines that the file is currently modified, it will respond to the second client's GETATTR as if the file had been modified locally at the server.


Since the form of the change attribute is determined by the server and is opaque to the client, the client and server need to agree on a method of communicating the modified state of the file. For the size attribute, the client will report its current view of the file size. For the change attribute, the handling is more involved.

変更属性の形式はサーバーによって決定され、クライアントに対して不透明であるため、クライアントとサーバーは、ファイルの変更された状態を通信する方法について合意する必要があります。 size属性の場合、クライアントはファイルサイズの現在のビューを報告します。変更属性の場合、処理はより複雑になります。

For the client, the following steps will be taken when receiving an OPEN_DELEGATE_WRITE delegation:


o The value of the change attribute will be obtained from the server and cached. Let this value be represented by c.

o 変更属性の値はサーバーから取得され、キャッシュされます。この値をcで表すとします。

o The client will create a value greater than c that will be used for communicating that modified data is held at the client. Let this value be represented by d.

o クライアントは、変更されたデータがクライアントで保持されていることを伝えるために使用されるcより大きい値を作成します。この値をdで表すとします。

o When the client is queried via CB_GETATTR for the change attribute, it checks to see if it holds modified data. If the file is modified, the value d is returned for the change attribute value. If this file is