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authorJ. Bruce Fields <bfields@redhat.com>2013-11-19 09:50:48 -0500
committerJ. Bruce Fields <bfields@redhat.com>2013-12-10 20:35:57 -0500
commit4bd8eabc29e17d9b29cee16077e1621e209a1b27 (patch)
tree91f3faf95e170410697488b49169f8fd18b269e5 /Documentation/filesystems/nfs
parent781c2a5a5f75eacc04663aced0f0f1a648d4f308 (diff)
nfsd4: update 4.1 nfsd status documentation
This has gone a little stale. Reported-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'Documentation/filesystems/nfs')
-rw-r--r--Documentation/filesystems/nfs/nfs41-server.txt42
1 files changed, 14 insertions, 28 deletions
diff --git a/Documentation/filesystems/nfs/nfs41-server.txt b/Documentation/filesystems/nfs/nfs41-server.txt
index 01c2db769791..b930ad087780 100644
--- a/Documentation/filesystems/nfs/nfs41-server.txt
+++ b/Documentation/filesystems/nfs/nfs41-server.txt
@@ -5,11 +5,11 @@ Server support for minorversion 1 can be controlled using the
by reading this file will contain either "+4.1" or "-4.1"
correspondingly.
-Currently, server support for minorversion 1 is disabled by default.
-It can be enabled at run time by writing the string "+4.1" to
+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. Use your user-mode
-nfs-utils to set this up; see rpc.nfsd(8)
+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
@@ -29,29 +29,6 @@ are still under development out of tree.
See http://wiki.linux-nfs.org/wiki/index.php/PNFS_prototype_design
for more information.
-The current implementation is intended for developers only: while it
-does support ordinary file operations on clients we have tested against
-(including the linux client), it is incomplete in ways which may limit
-features unexpectedly, cause known bugs in rare cases, or cause
-interoperability problems with future clients. Known issues:
-
- - gss support is questionable: currently mounts with kerberos
- from a linux client are possible, but we aren't really
- conformant with the spec (for example, we don't use kerberos
- on the backchannel correctly).
- - We do not support SSV, which provides security for shared
- client-server state (thus preventing unauthorized tampering
- with locks and opens, for example). It is mandatory for
- servers to support this, though no clients use it yet.
-
-In addition, some limitations are inherited from the current NFSv4
-implementation:
-
- - Incomplete delegation enforcement: if a file is renamed or
- unlinked by a local process, a client holding a delegation may
- continue to indefinitely allow opens of the file under the old
- name.
-
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)
@@ -169,6 +146,16 @@ NS*| CB_WANTS_CANCELLED | OPT | FDELG, | Section 20.10 |
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
@@ -176,7 +163,6 @@ DELEGPURGE:
now.
EXCHANGE_ID:
-* only SP4_NONE state protection supported
* implementation ids are ignored
CREATE_SESSION: