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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:54:33 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:54:33 -0400
commita87e84b5cdfacf11af4e8a85c4bca9793658536f (patch)
treef8e3cb2d339d8ed0e987d55f725e501730cdc81d /Documentation/filesystems
parent342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca (diff)
parent3c394ddaa7ea4205f933fd9b481166b2669368a9 (diff)
Merge branch 'for-2.6.32' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.32' of git://linux-nfs.org/~bfields/linux: (68 commits) nfsd4: nfsv4 clients should cross mountpoints nfsd: revise 4.1 status documentation sunrpc/cache: avoid variable over-loading in cache_defer_req sunrpc/cache: use list_del_init for the list_head entries in cache_deferred_req nfsd: return success for non-NFS4 nfs4_state_start nfsd41: Refactor create_client() nfsd41: modify nfsd4.1 backchannel to use new xprt class nfsd41: Backchannel: Implement cb_recall over NFSv4.1 nfsd41: Backchannel: cb_sequence callback nfsd41: Backchannel: Setup sequence information nfsd41: Backchannel: Server backchannel RPC wait queue nfsd41: Backchannel: Add sequence arguments to callback RPC arguments nfsd41: Backchannel: callback infrastructure nfsd4: use common rpc_cred for all callbacks nfsd4: allow nfs4 state startup to fail SUNRPC: Defer the auth_gss upcall when the RPC call is asynchronous nfsd4: fix null dereference creating nfsv4 callback client nfsd4: fix whitespace in NFSPROC4_CLNT_CB_NULL definition nfsd41: sunrpc: add new xprt class for nfsv4.1 backchannel sunrpc/cache: simplify cache_fresh_locked and cache_fresh_unlocked. ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/nfs41-server.txt54
1 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/filesystems/nfs41-server.txt b/Documentation/filesystems/nfs41-server.txt
index 05d81cbcb2e1..5920fe26e6ff 100644
--- a/Documentation/filesystems/nfs41-server.txt
+++ b/Documentation/filesystems/nfs41-server.txt
@@ -11,6 +11,11 @@ the /proc/fs/nfsd/versions control file. Note that to write this
11control file, the nfsd service must be taken down. Use your user-mode 11control file, the nfsd service must be taken down. Use your user-mode
12nfs-utils to set this up; see rpc.nfsd(8) 12nfs-utils to set this up; see rpc.nfsd(8)
13 13
14(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
15"-4", respectively. Therefore, code meant to work on both new and old
16kernels must turn 4.1 on or off *before* turning support for version 4
17on or off; rpc.nfsd does this correctly.)
18
14The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based 19The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
15on the latest NFSv4.1 Internet Draft: 20on the latest NFSv4.1 Internet Draft:
16http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-29 21http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-29
@@ -25,6 +30,49 @@ are still under development out of tree.
25See http://wiki.linux-nfs.org/wiki/index.php/PNFS_prototype_design 30See http://wiki.linux-nfs.org/wiki/index.php/PNFS_prototype_design
26for more information. 31for more information.
27 32
33The current implementation is intended for developers only: while it
34does support ordinary file operations on clients we have tested against
35(including the linux client), it is incomplete in ways which may limit
36features unexpectedly, cause known bugs in rare cases, or cause
37interoperability problems with future clients. Known issues:
38
39 - gss support is questionable: currently mounts with kerberos
40 from a linux client are possible, but we aren't really
41 conformant with the spec (for example, we don't use kerberos
42 on the backchannel correctly).
43 - no trunking support: no clients currently take advantage of
44 trunking, but this is a mandatory failure, and its use is
45 recommended to clients in a number of places. (E.g. to ensure
46 timely renewal in case an existing connection's retry timeouts
47 have gotten too long; see section 8.3 of the draft.)
48 Therefore, lack of this feature may cause future clients to
49 fail.
50 - Incomplete backchannel support: incomplete backchannel gss
51 support and no support for BACKCHANNEL_CTL mean that
52 callbacks (hence delegations and layouts) may not be
53 available and clients confused by the incomplete
54 implementation may fail.
55 - Server reboot recovery is unsupported; if the server reboots,
56 clients may fail.
57 - We do not support SSV, which provides security for shared
58 client-server state (thus preventing unauthorized tampering
59 with locks and opens, for example). It is mandatory for
60 servers to support this, though no clients use it yet.
61 - Mandatory operations which we do not support, such as
62 DESTROY_CLIENTID, FREE_STATEID, SECINFO_NO_NAME, and
63 TEST_STATEID, are not currently used by clients, but will be
64 (and the spec recommends their uses in common cases), and
65 clients should not be expected to know how to recover from the
66 case where they are not supported. This will eventually cause
67 interoperability failures.
68
69In addition, some limitations are inherited from the current NFSv4
70implementation:
71
72 - Incomplete delegation enforcement: if a file is renamed or
73 unlinked, a client holding a delegation may continue to
74 indefinitely allow opens of the file under the old name.
75
28The table below, taken from the NFSv4.1 document, lists 76The table below, taken from the NFSv4.1 document, lists
29the operations that are mandatory to implement (REQ), optional 77the operations that are mandatory to implement (REQ), optional
30(OPT), and NFSv4.0 operations that are required not to implement (MNI) 78(OPT), and NFSv4.0 operations that are required not to implement (MNI)
@@ -142,6 +190,12 @@ NS*| CB_WANTS_CANCELLED | OPT | FDELG, | Section 20.10 |
142 190
143Implementation notes: 191Implementation notes:
144 192
193DELEGPURGE:
194* mandatory only for servers that support CLAIM_DELEGATE_PREV and/or
195 CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
196 persist across client reboots). Thus we need not implement this for
197 now.
198
145EXCHANGE_ID: 199EXCHANGE_ID:
146* only SP4_NONE state protection supported 200* only SP4_NONE state protection supported
147* implementation ids are ignored 201* implementation ids are ignored