Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4bd8eabc authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: update 4.1 nfsd status documentation 



This has gone a little stale.

Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 781c2a5a

Documentation/filesystems/nfs/nfs41-server.txt

+14 −28
Original line number Original line Diff line number Diff line
@@ -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"

by reading this file will contain either "+4.1" or "-4.1"

correspondingly.

correspondingly.





Currently, server support for minorversion 1 is disabled by default.

Currently, server support for minorversion 1 is enabled by default.

It can be enabled at run time by writing the string "+4.1" to

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

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

control file, the nfsd service must be taken down.  You can use rpc.nfsd

nfs-utils to set this up; see rpc.nfsd(8)

for this; see rpc.nfsd(8).





(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and

(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

"-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

See http://wiki.linux-nfs.org/wiki/index.php/PNFS_prototype_design

for more information.

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 table below, taken from the NFSv4.1 document, lists

the operations that are mandatory to implement (REQ), optional

the operations that are mandatory to implement (REQ), optional

(OPT), and NFSv4.0 operations that are required not to implement (MNI)

(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:

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:

DELEGPURGE:

* mandatory only for servers that support CLAIM_DELEGATE_PREV and/or

* mandatory only for servers that support CLAIM_DELEGATE_PREV and/or

  CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that

  CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
@@ -176,7 +163,6 @@ DELEGPURGE: 
  now.

  now.





EXCHANGE_ID:

EXCHANGE_ID:

* only SP4_NONE state protection supported

* implementation ids are ignored

* implementation ids are ignored





CREATE_SESSION:

CREATE_SESSION: