--- /dev/null
+NFSv4.1 Server Implementation
+
+Server support for minorversion 1 can be controlled using the
+/proc/fs/nfsd/versions control file. The string output returned
+by reading this file will contain either "+4.1" or "-4.1"
+correspondingly.
+
+Currently, server support for minorversion 1 is enabled by default.
+It can be disabled at run time by writing the string "-4.1" to
+the /proc/fs/nfsd/versions control file. Note that to write this
+control file, the nfsd service must be taken down. You can use rpc.nfsd
+for this; see rpc.nfsd(8).
+
+(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
+"-4", respectively. Therefore, code meant to work on both new and old
+kernels must turn 4.1 on or off *before* turning support for version 4
+on or off; rpc.nfsd does this correctly.)
+
+The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
+on RFC 5661.
+
+From the many new features in NFSv4.1 the current implementation
+focuses on the mandatory-to-implement NFSv4.1 Sessions, providing
+"exactly once" semantics and better control and throttling of the
+resources allocated for each client.
+
+The table below, taken from the NFSv4.1 document, lists
+the operations that are mandatory to implement (REQ), optional
+(OPT), and NFSv4.0 operations that are required not to implement (MNI)
+in minor version 1. The first column indicates the operations that
+are not supported yet by the linux server implementation.
+
+The OPTIONAL features identified and their abbreviations are as follows:
+ pNFS Parallel NFS
+ FDELG File Delegations
+ DDELG Directory Delegations
+
+The following abbreviations indicate the linux server implementation status.
+ I Implemented NFSv4.1 operations.
+ NS Not Supported.
+ NS* Unimplemented optional feature.
+
+Operations
+
+ +----------------------+------------+--------------+----------------+
+ | Operation | REQ, REC, | Feature | Definition |
+ | | OPT, or | (REQ, REC, | |
+ | | MNI | or OPT) | |
+ +----------------------+------------+--------------+----------------+
+ | ACCESS | REQ | | Section 18.1 |
+I | BACKCHANNEL_CTL | REQ | | Section 18.33 |
+I | BIND_CONN_TO_SESSION | REQ | | Section 18.34 |
+ | CLOSE | REQ | | Section 18.2 |
+ | COMMIT | REQ | | Section 18.3 |
+ | CREATE | REQ | | Section 18.4 |
+I | CREATE_SESSION | REQ | | Section 18.36 |
+NS*| DELEGPURGE | OPT | FDELG (REQ) | Section 18.5 |
+ | DELEGRETURN | OPT | FDELG, | Section 18.6 |
+ | | | DDELG, pNFS | |
+ | | | (REQ) | |
+I | DESTROY_CLIENTID | REQ | | Section 18.50 |
+I | DESTROY_SESSION | REQ | | Section 18.37 |
+I | EXCHANGE_ID | REQ | | Section 18.35 |
+I | FREE_STATEID | REQ | | Section 18.38 |
+ | GETATTR | REQ | | Section 18.7 |
+I | GETDEVICEINFO | OPT | pNFS (REQ) | Section 18.40 |
+NS*| GETDEVICELIST | OPT | pNFS (OPT) | Section 18.41 |
+ | GETFH | REQ | | Section 18.8 |
+NS*| GET_DIR_DELEGATION | OPT | DDELG (REQ) | Section 18.39 |
+I | LAYOUTCOMMIT | OPT | pNFS (REQ) | Section 18.42 |
+I | LAYOUTGET | OPT | pNFS (REQ) | Section 18.43 |
+I | LAYOUTRETURN | OPT | pNFS (REQ) | Section 18.44 |
+ | LINK | OPT | | Section 18.9 |
+ | LOCK | REQ | | Section 18.10 |
+ | LOCKT | REQ | | Section 18.11 |
+ | LOCKU | REQ | | Section 18.12 |
+ | LOOKUP | REQ | | Section 18.13 |
+ | LOOKUPP | REQ | | Section 18.14 |
+ | NVERIFY | REQ | | Section 18.15 |
+ | OPEN | REQ | | Section 18.16 |
+NS*| OPENATTR | OPT | | Section 18.17 |
+ | OPEN_CONFIRM | MNI | | N/A |
+ | OPEN_DOWNGRADE | REQ | | Section 18.18 |
+ | PUTFH | REQ | | Section 18.19 |
+ | PUTPUBFH | REQ | | Section 18.20 |
+ | PUTROOTFH | REQ | | Section 18.21 |
+ | READ | REQ | | Section 18.22 |
+ | READDIR | REQ | | Section 18.23 |
+ | READLINK | OPT | | Section 18.24 |
+ | RECLAIM_COMPLETE | REQ | | Section 18.51 |
+ | RELEASE_LOCKOWNER | MNI | | N/A |
+ | REMOVE | REQ | | Section 18.25 |
+ | RENAME | REQ | | Section 18.26 |
+ | RENEW | MNI | | N/A |
+ | RESTOREFH | REQ | | Section 18.27 |
+ | SAVEFH | REQ | | Section 18.28 |
+ | SECINFO | REQ | | Section 18.29 |
+I | SECINFO_NO_NAME | REC | pNFS files | Section 18.45, |
+ | | | layout (REQ) | Section 13.12 |
+I | SEQUENCE | REQ | | Section 18.46 |
+ | SETATTR | REQ | | Section 18.30 |
+ | SETCLIENTID | MNI | | N/A |
+ | SETCLIENTID_CONFIRM | MNI | | N/A |
+NS | SET_SSV | REQ | | Section 18.47 |
+I | TEST_STATEID | REQ | | Section 18.48 |
+ | VERIFY | REQ | | Section 18.31 |
+NS*| WANT_DELEGATION | OPT | FDELG (OPT) | Section 18.49 |
+ | WRITE | REQ | | Section 18.32 |
+
+Callback Operations
+
+ +-------------------------+-----------+-------------+---------------+
+ | Operation | REQ, REC, | Feature | Definition |
+ | | OPT, or | (REQ, REC, | |
+ | | MNI | or OPT) | |
+ +-------------------------+-----------+-------------+---------------+
+ | CB_GETATTR | OPT | FDELG (REQ) | Section 20.1 |
+I | CB_LAYOUTRECALL | OPT | pNFS (REQ) | Section 20.3 |
+NS*| CB_NOTIFY | OPT | DDELG (REQ) | Section 20.4 |
+NS*| CB_NOTIFY_DEVICEID | OPT | pNFS (OPT) | Section 20.12 |
+NS*| CB_NOTIFY_LOCK | OPT | | Section 20.11 |
+NS*| CB_PUSH_DELEG | OPT | FDELG (OPT) | Section 20.5 |
+ | CB_RECALL | OPT | FDELG, | Section 20.2 |
+ | | | DDELG, pNFS | |
+ | | | (REQ) | |
+NS*| CB_RECALL_ANY | OPT | FDELG, | Section 20.6 |
+ | | | DDELG, pNFS | |
+ | | | (REQ) | |
+NS | CB_RECALL_SLOT | REQ | | Section 20.8 |
+NS*| CB_RECALLABLE_OBJ_AVAIL | OPT | DDELG, pNFS | Section 20.7 |
+ | | | (REQ) | |
+I | CB_SEQUENCE | OPT | FDELG, | Section 20.9 |
+ | | | DDELG, pNFS | |
+ | | | (REQ) | |
+NS*| CB_WANTS_CANCELLED | OPT | FDELG, | Section 20.10 |
+ | | | DDELG, pNFS | |
+ | | | (REQ) | |
+ +-------------------------+-----------+-------------+---------------+
+
+Implementation notes:
+
+SSV:
+* The spec claims this is mandatory, but we don't actually know of any
+ implementations, so we're ignoring it for now. The server returns
+ NFS4ERR_ENCR_ALG_UNSUPP on EXCHANGE_ID, which should be future-proof.
+
+GSS on the backchannel:
+* Again, theoretically required but not widely implemented (in
+ particular, the current Linux client doesn't request it). We return
+ NFS4ERR_ENCR_ALG_UNSUPP on CREATE_SESSION.
+
+DELEGPURGE:
+* mandatory only for servers that support CLAIM_DELEGATE_PREV and/or
+ CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
+ persist across client reboots). Thus we need not implement this for
+ now.
+
+EXCHANGE_ID:
+* implementation ids are ignored
+
+CREATE_SESSION:
+* backchannel attributes are ignored
+
+SEQUENCE:
+* no support for dynamic slot table renegotiation (optional)
+
+Nonstandard compound limitations:
+* No support for a sessions fore channel RPC compound that requires both a
+ ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
+ fail to live up to the promise we made in CREATE_SESSION fore channel
+ negotiation.
+
+See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.
Code Review / kvmfornfv.git / blobdiff