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1=============================2NFSv4.1 Server Implementation3=============================4 5Server support for minorversion 1 can be controlled using the6/proc/fs/nfsd/versions control file. The string output returned7by 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" to12the /proc/fs/nfsd/versions control file. Note that to write this13control file, the nfsd service must be taken down. You can use rpc.nfsd14for this; see rpc.nfsd(8).15 16(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and17"-4", respectively. Therefore, code meant to work on both new and old18kernels must turn 4.1 on or off *before* turning support for version 419on or off; rpc.nfsd does this correctly.)20 21The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based22on RFC 5661.23 24From the many new features in NFSv4.1 the current implementation25focuses on the mandatory-to-implement NFSv4.1 Sessions, providing26"exactly once" semantics and better control and throttling of the27resources allocated for each client.28 29The table below, taken from the NFSv4.1 document, lists30the operations that are mandatory to implement (REQ), optional31(OPT), and NFSv4.0 operations that are required not to implement (MNI)32in minor version 1. The first column indicates the operations that33are not supported yet by the linux server implementation.34 35The OPTIONAL features identified and their abbreviations are as follows:36 37- **pNFS** Parallel NFS38- **FDELG** File Delegations39- **DDELG** Directory Delegations40 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 47Operations48==========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 Operations174===================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 any227 implementations, so we're ignoring it for now. The server returns228 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 (in232 particular, the current Linux client doesn't request it). We return233 NFS4ERR_ENCR_ALG_UNSUPP on CREATE_SESSION.234 235DELEGPURGE:236 mandatory only for servers that support CLAIM_DELEGATE_PREV and/or237 CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that238 persist across client reboots). Thus we need not implement this for239 now.240 241EXCHANGE_ID:242 implementation ids are ignored243 244CREATE_SESSION:245 backchannel attributes are ignored246 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 a252 ca_maxrequestsize request and a ca_maxresponsesize reply, so we may253 fail to live up to the promise we made in CREATE_SESSION fore channel254 negotiation.255 256See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.257