1============================= 2NFSv4.1 Server Implementation 3============================= 4 5Server support for minorversion 1 can be controlled using the 6/proc/fs/nfsd/versions control file. The string output returned 7by reading this file will contain either "+4.1" or "-4.1" 8correspondingly. 9 10Currently, server support for minorversion 1 is enabled by default. 11It can be disabled at run time by writing the string "-4.1" to 12the /proc/fs/nfsd/versions control file. Note that to write this 13control file, the nfsd service must be taken down. You can use rpc.nfsd 14for this; see rpc.nfsd(8). 15 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 18kernels must turn 4.1 on or off *before* turning support for version 4 19on or off; rpc.nfsd does this correctly.) 20 21The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based 22on RFC 5661. 23 24From the many new features in NFSv4.1 the current implementation 25focuses on the mandatory-to-implement NFSv4.1 Sessions, providing 26"exactly once" semantics and better control and throttling of the 27resources allocated for each client. 28 29The table below, taken from the NFSv4.1 document, lists 30the operations that are mandatory to implement (REQ), optional 31(OPT), and NFSv4.0 operations that are required not to implement (MNI) 32in minor version 1. The first column indicates the operations that 33are not supported yet by the linux server implementation. 34 35The OPTIONAL features identified and their abbreviations are as follows: 36 37- **pNFS** Parallel NFS 38- **FDELG** File Delegations 39- **DDELG** Directory Delegations 40 41The following abbreviations indicate the linux server implementation status. 42 43- **I** Implemented NFSv4.1 operations. 44- **NS** Not Supported. 45- **NS\*** Unimplemented optional feature. 46 47Operations 48========== 49 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+-----------------------+----------------------+---------------------+---------------------------+----------------+ 73| | | | (REQ) | | 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+-----------------------+----------------------+---------------------+---------------------------+----------------+ 171 172 173Callback Operations 174=================== 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+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 194| | | | (REQ) | | 195+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 196| NS* | CB_RECALL_ANY | OPT | FDELG, | Section 20.6 | 197+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 198| | | | DDELG, pNFS | | 199+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 200| | | | (REQ) | | 201+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 202| NS | CB_RECALL_SLOT | REQ | | Section 20.8 | 203+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 204| NS* | CB_RECALLABLE_OBJ_AVAIL | OPT | DDELG, pNFS | Section 20.7 | 205+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 206| | | | (REQ) | | 207+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 208| I | CB_SEQUENCE | OPT | FDELG, | Section 20.9 | 209+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 210| | | | DDELG, pNFS | | 211+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 212| | | | (REQ) | | 213+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 214| NS* | CB_WANTS_CANCELLED | OPT | FDELG, | Section 20.10 | 215+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 216| | | | DDELG, pNFS | | 217+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 218| | | | (REQ) | | 219+-----------------------+-------------------------+---------------------+---------------------------+---------------+ 220 221 222Implementation notes: 223===================== 224 225SSV: 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. 229 230GSS 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. 234 235DELEGPURGE: 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 239 now. 240 241EXCHANGE_ID: 242 implementation ids are ignored 243 244CREATE_SESSION: 245 backchannel attributes are ignored 246 247SEQUENCE: 248 no support for dynamic slot table renegotiation (optional) 249 250Nonstandard 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 254 negotiation. 255 256See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues. 257