1 =============================
2 NFSv4.1 Server Implementation
3 =============================
5 Server support for minorversion 1 can be controlled using the
6 /proc/fs/nfsd/versions control file. The string output returned
7 by reading this file will contain either "+4.1" or "-4.1"
10 Currently, server support for minorversion 1 is enabled by default.
11 It can be disabled at run time by writing the string "-4.1" to
12 the /proc/fs/nfsd/versions control file. Note that to write this
13 control file, the nfsd service must be taken down. You can use rpc.nfsd
14 for this; see rpc.nfsd(8).
16 (Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
17 "-4", respectively. Therefore, code meant to work on both new and old
18 kernels must turn 4.1 on or off *before* turning support for version 4
19 on or off; rpc.nfsd does this correctly.)
21 The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
24 From the many new features in NFSv4.1 the current implementation
25 focuses on the mandatory-to-implement NFSv4.1 Sessions, providing
26 "exactly once" semantics and better control and throttling of the
27 resources allocated for each client.
29 The table below, taken from the NFSv4.1 document, lists
30 the operations that are mandatory to implement (REQ), optional
31 (OPT), and NFSv4.0 operations that are required not to implement (MNI)
32 in minor version 1. The first column indicates the operations that
33 are not supported yet by the linux server implementation.
35 The OPTIONAL features identified and their abbreviations are as follows:
37 - **pNFS** Parallel NFS
38 - **FDELG** File Delegations
39 - **DDELG** Directory Delegations
41 The following abbreviations indicate the linux server implementation status.
43 - **I** Implemented NFSv4.1 operations.
44 - **NS** Not Supported.
45 - **NS\*** Unimplemented optional feature.
50 +-----------------------+----------------------+---------------------+---------------------------+----------------+
51 | Implementation status | Operation | REQ,REC, OPT or NMI | Feature (REQ, REC or OPT) | Definition |
52 +=======================+======================+=====================+===========================+================+
53 | | ACCESS | REQ | | Section 18.1 |
54 +-----------------------+----------------------+---------------------+---------------------------+----------------+
55 | I | BACKCHANNEL_CTL | REQ | | Section 18.33 |
56 +-----------------------+----------------------+---------------------+---------------------------+----------------+
57 | I | BIND_CONN_TO_SESSION | REQ | | Section 18.34 |
58 +-----------------------+----------------------+---------------------+---------------------------+----------------+
59 | | CLOSE | REQ | | Section 18.2 |
60 +-----------------------+----------------------+---------------------+---------------------------+----------------+
61 | | COMMIT | REQ | | Section 18.3 |
62 +-----------------------+----------------------+---------------------+---------------------------+----------------+
63 | | CREATE | REQ | | Section 18.4 |
64 +-----------------------+----------------------+---------------------+---------------------------+----------------+
65 | I | CREATE_SESSION | REQ | | Section 18.36 |
66 +-----------------------+----------------------+---------------------+---------------------------+----------------+
67 | NS* | DELEGPURGE | OPT | FDELG (REQ) | Section 18.5 |
68 +-----------------------+----------------------+---------------------+---------------------------+----------------+
69 | | DELEGRETURN | OPT | FDELG, | Section 18.6 |
70 +-----------------------+----------------------+---------------------+---------------------------+----------------+
71 | | | | DDELG, pNFS | |
72 +-----------------------+----------------------+---------------------+---------------------------+----------------+
74 +-----------------------+----------------------+---------------------+---------------------------+----------------+
75 | I | DESTROY_CLIENTID | REQ | | Section 18.50 |
76 +-----------------------+----------------------+---------------------+---------------------------+----------------+
77 | I | DESTROY_SESSION | REQ | | Section 18.37 |
78 +-----------------------+----------------------+---------------------+---------------------------+----------------+
79 | I | EXCHANGE_ID | REQ | | Section 18.35 |
80 +-----------------------+----------------------+---------------------+---------------------------+----------------+
81 | I | FREE_STATEID | REQ | | Section 18.38 |
82 +-----------------------+----------------------+---------------------+---------------------------+----------------+
83 | | GETATTR | REQ | | Section 18.7 |
84 +-----------------------+----------------------+---------------------+---------------------------+----------------+
85 | I | GETDEVICEINFO | OPT | pNFS (REQ) | Section 18.40 |
86 +-----------------------+----------------------+---------------------+---------------------------+----------------+
87 | NS* | GETDEVICELIST | OPT | pNFS (OPT) | Section 18.41 |
88 +-----------------------+----------------------+---------------------+---------------------------+----------------+
89 | | GETFH | REQ | | Section 18.8 |
90 +-----------------------+----------------------+---------------------+---------------------------+----------------+
91 | NS* | GET_DIR_DELEGATION | OPT | DDELG (REQ) | Section 18.39 |
92 +-----------------------+----------------------+---------------------+---------------------------+----------------+
93 | I | LAYOUTCOMMIT | OPT | pNFS (REQ) | Section 18.42 |
94 +-----------------------+----------------------+---------------------+---------------------------+----------------+
95 | I | LAYOUTGET | OPT | pNFS (REQ) | Section 18.43 |
96 +-----------------------+----------------------+---------------------+---------------------------+----------------+
97 | I | LAYOUTRETURN | OPT | pNFS (REQ) | Section 18.44 |
98 +-----------------------+----------------------+---------------------+---------------------------+----------------+
99 | | LINK | OPT | | Section 18.9 |
100 +-----------------------+----------------------+---------------------+---------------------------+----------------+
101 | | LOCK | REQ | | Section 18.10 |
102 +-----------------------+----------------------+---------------------+---------------------------+----------------+
103 | | LOCKT | REQ | | Section 18.11 |
104 +-----------------------+----------------------+---------------------+---------------------------+----------------+
105 | | LOCKU | REQ | | Section 18.12 |
106 +-----------------------+----------------------+---------------------+---------------------------+----------------+
107 | | LOOKUP | REQ | | Section 18.13 |
108 +-----------------------+----------------------+---------------------+---------------------------+----------------+
109 | | LOOKUPP | REQ | | Section 18.14 |
110 +-----------------------+----------------------+---------------------+---------------------------+----------------+
111 | | NVERIFY | REQ | | Section 18.15 |
112 +-----------------------+----------------------+---------------------+---------------------------+----------------+
113 | | OPEN | REQ | | Section 18.16 |
114 +-----------------------+----------------------+---------------------+---------------------------+----------------+
115 | NS* | OPENATTR | OPT | | Section 18.17 |
116 +-----------------------+----------------------+---------------------+---------------------------+----------------+
117 | | OPEN_CONFIRM | MNI | | N/A |
118 +-----------------------+----------------------+---------------------+---------------------------+----------------+
119 | | OPEN_DOWNGRADE | REQ | | Section 18.18 |
120 +-----------------------+----------------------+---------------------+---------------------------+----------------+
121 | | PUTFH | REQ | | Section 18.19 |
122 +-----------------------+----------------------+---------------------+---------------------------+----------------+
123 | | PUTPUBFH | REQ | | Section 18.20 |
124 +-----------------------+----------------------+---------------------+---------------------------+----------------+
125 | | PUTROOTFH | REQ | | Section 18.21 |
126 +-----------------------+----------------------+---------------------+---------------------------+----------------+
127 | | READ | REQ | | Section 18.22 |
128 +-----------------------+----------------------+---------------------+---------------------------+----------------+
129 | | READDIR | REQ | | Section 18.23 |
130 +-----------------------+----------------------+---------------------+---------------------------+----------------+
131 | | READLINK | OPT | | Section 18.24 |
132 +-----------------------+----------------------+---------------------+---------------------------+----------------+
133 | | RECLAIM_COMPLETE | REQ | | Section 18.51 |
134 +-----------------------+----------------------+---------------------+---------------------------+----------------+
135 | | RELEASE_LOCKOWNER | MNI | | N/A |
136 +-----------------------+----------------------+---------------------+---------------------------+----------------+
137 | | REMOVE | REQ | | Section 18.25 |
138 +-----------------------+----------------------+---------------------+---------------------------+----------------+
139 | | RENAME | REQ | | Section 18.26 |
140 +-----------------------+----------------------+---------------------+---------------------------+----------------+
141 | | RENEW | MNI | | N/A |
142 +-----------------------+----------------------+---------------------+---------------------------+----------------+
143 | | RESTOREFH | REQ | | Section 18.27 |
144 +-----------------------+----------------------+---------------------+---------------------------+----------------+
145 | | SAVEFH | REQ | | Section 18.28 |
146 +-----------------------+----------------------+---------------------+---------------------------+----------------+
147 | | SECINFO | REQ | | Section 18.29 |
148 +-----------------------+----------------------+---------------------+---------------------------+----------------+
149 | I | SECINFO_NO_NAME | REC | pNFS files | Section 18.45, |
150 +-----------------------+----------------------+---------------------+---------------------------+----------------+
151 | | | | layout (REQ) | Section 13.12 |
152 +-----------------------+----------------------+---------------------+---------------------------+----------------+
153 | I | SEQUENCE | REQ | | Section 18.46 |
154 +-----------------------+----------------------+---------------------+---------------------------+----------------+
155 | | SETATTR | REQ | | Section 18.30 |
156 +-----------------------+----------------------+---------------------+---------------------------+----------------+
157 | | SETCLIENTID | MNI | | N/A |
158 +-----------------------+----------------------+---------------------+---------------------------+----------------+
159 | | SETCLIENTID_CONFIRM | MNI | | N/A |
160 +-----------------------+----------------------+---------------------+---------------------------+----------------+
161 | NS | SET_SSV | REQ | | Section 18.47 |
162 +-----------------------+----------------------+---------------------+---------------------------+----------------+
163 | I | TEST_STATEID | REQ | | Section 18.48 |
164 +-----------------------+----------------------+---------------------+---------------------------+----------------+
165 | | VERIFY | REQ | | Section 18.31 |
166 +-----------------------+----------------------+---------------------+---------------------------+----------------+
167 | NS* | WANT_DELEGATION | OPT | FDELG (OPT) | Section 18.49 |
168 +-----------------------+----------------------+---------------------+---------------------------+----------------+
169 | | WRITE | REQ | | Section 18.32 |
170 +-----------------------+----------------------+---------------------+---------------------------+----------------+
175 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
176 | Implementation status | Operation | REQ,REC, OPT or NMI | Feature (REQ, REC or OPT) | Definition |
177 +=======================+=========================+=====================+===========================+===============+
178 | | CB_GETATTR | OPT | FDELG (REQ) | Section 20.1 |
179 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
180 | I | CB_LAYOUTRECALL | OPT | pNFS (REQ) | Section 20.3 |
181 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
182 | NS* | CB_NOTIFY | OPT | DDELG (REQ) | Section 20.4 |
183 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
184 | NS* | CB_NOTIFY_DEVICEID | OPT | pNFS (OPT) | Section 20.12 |
185 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
186 | NS* | CB_NOTIFY_LOCK | OPT | | Section 20.11 |
187 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
188 | NS* | CB_PUSH_DELEG | OPT | FDELG (OPT) | Section 20.5 |
189 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
190 | | CB_RECALL | OPT | FDELG, | Section 20.2 |
191 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
192 | | | | DDELG, pNFS | |
193 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
195 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
196 | NS* | CB_RECALL_ANY | OPT | FDELG, | Section 20.6 |
197 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
198 | | | | DDELG, pNFS | |
199 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
201 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
202 | NS | CB_RECALL_SLOT | REQ | | Section 20.8 |
203 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
204 | NS* | CB_RECALLABLE_OBJ_AVAIL | OPT | DDELG, pNFS | Section 20.7 |
205 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
207 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
208 | I | CB_SEQUENCE | OPT | FDELG, | Section 20.9 |
209 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
210 | | | | DDELG, pNFS | |
211 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
213 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
214 | NS* | CB_WANTS_CANCELLED | OPT | FDELG, | Section 20.10 |
215 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
216 | | | | DDELG, pNFS | |
217 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
219 +-----------------------+-------------------------+---------------------+---------------------------+---------------+
222 Implementation notes:
223 =====================
226 The spec claims this is mandatory, but we don't actually know of any
227 implementations, so we're ignoring it for now. The server returns
228 NFS4ERR_ENCR_ALG_UNSUPP on EXCHANGE_ID, which should be future-proof.
230 GSS on the backchannel:
231 Again, theoretically required but not widely implemented (in
232 particular, the current Linux client doesn't request it). We return
233 NFS4ERR_ENCR_ALG_UNSUPP on CREATE_SESSION.
236 mandatory only for servers that support CLAIM_DELEGATE_PREV and/or
237 CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
238 persist across client reboots). Thus we need not implement this for
242 implementation ids are ignored
245 backchannel attributes are ignored
248 no support for dynamic slot table renegotiation (optional)
250 Nonstandard compound limitations:
251 No support for a sessions fore channel RPC compound that requires both a
252 ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
253 fail to live up to the promise we made in CREATE_SESSION fore channel
256 See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.