Commit Graph

953 Commits

Author SHA1 Message Date
Trond Myklebust
df52699e4f NFSv4.1: Don't cache deviceids that have no notifications
The spec says that once all layouts that reference a given deviceid
have been returned, then we are only allowed to continue to cache
the deviceid if the metadata server supports notifications.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27 12:32:24 -04:00
Trond Myklebust
4e59080397 NFSv4.1: Allow getdeviceinfo to return notification info back to caller
We are only allowed to cache deviceinfo if the server supports notifications
and actually promises to call us back when changes occur. Right now, we
request those notifications, but then we don't check the server's reply.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27 12:32:24 -04:00
Trond Myklebust
e11259f920 NFSv4.1: Clear the old state by our client id before establishing a new lease
If the call to exchange-id returns with the EXCHGID4_FLAG_CONFIRMED_R flag
set, then that means our lease was established by a previous mount instance.
Ensure that we detect this situation, and that we clear the state held by
that mount.

Reported-by: Jorge Mora <Jorge.Mora@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-03 21:52:30 -05:00
Anna Schumaker
369d6b7f00 NFS: Fix stateid used for NFS v4 closes
After 566fcec60 the client uses the "current stateid" from the
nfs4_state structure to close a file.  This could potentially contain a
delegation stateid, which is disallowed by the protocol and causes
servers to return NFS4ERR_BAD_STATEID.  This patch restores the
(correct) behavior of sending the open stateid to close a file.

Reported-by: Olga Kornievskaia <kolga@netapp.com>
Fixes: 566fcec60 (NFSv4: Fix an atomicity problem in CLOSE)
Signed-off-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-02 18:06:42 -05:00
Trond Myklebust
3235b40303 NFSv4: Set a barrier in the update_changeattr() helper
Ensure that we don't regress the changes that were made to the
directory.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
2015-03-01 23:23:06 -05:00
Trond Myklebust
a08a8cd375 NFS: Add attribute update barriers to NFS writebacks
Ensure that other operations that race with our write RPC calls
cannot revert the file size updates that were made on the server.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
2015-03-01 23:23:06 -05:00
Trond Myklebust
f044636d97 NFS: Add attribute update barriers to nfs_setattr_update_inode()
Ensure that other operations which raced with our setattr RPC call
cannot revert the file attribute changes that were made on the server.
To do so, we artificially bump the attribute generation counter on
the inode so that all calls to nfs_fattr_init() that precede ours
will be dropped.

The motivation for the patch came from Chuck Lever's reports of readaheads
racing with truncate operations and causing the file size to be reverted.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
2015-03-01 23:23:05 -05:00
Trond Myklebust
be36e185bd NFSv4: nfs4_open_recover_helper() must set share access
The share access mode is now specified as an argument in the nfs4_opendata,
and so nfs4_open_recover_helper() needs to call nfs4_map_atomic_open_share()
in order to set it.

Fixes: 6ae373394c ("NFSv4.1: Ask for no delegation on OPEN if using O_DIRECT")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-27 17:10:40 -05:00
Trond Myklebust
71a097c6de NFSv4.1: Clean up bind_conn_to_session
We don't need to fake up an entire session in order retrieve the arguments.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-18 13:11:09 -08:00
Trond Myklebust
b1c0df5fad NFSv4.1: Don't set up a backchannel if the server didn't agree to do so
If the server doesn't agree to out backchannel setup request, then
don't set one up.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-18 12:30:47 -08:00
Trond Myklebust
79969dd12e NFSv4.1: Clean up create_session
Don't decode directly into the shared struct session

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-18 12:28:50 -08:00
Trond Myklebust
5a0ec8acb9 NFSv4.1: Pin the inode and super block in asynchronous layoutreturns
If we're sending an asynchronous layoutreturn, then we need to ensure
that the inode and the super block remain pinned.

Cc: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
2015-02-05 22:16:45 -05:00
Trond Myklebust
472e259449 NFSv4.1: Pin the inode and super block in asynchronous layoutcommit
If we're sending an asynchronous layoutcommit, then we need to ensure
that the inode and the super block remain pinned.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
2015-02-05 22:16:33 -05:00
Trond Myklebust
ea7c38fef0 NFSv4: Ensure we reference the inode for return-on-close in delegreturn
If we have to do a return-on-close in the delegreturn code, then
we must ensure that the inode and super block remain referenced.

Cc: Peng Tao <tao.peng@primarydata.com>
Cc: stable@vger.kernel.org # 3.17.x
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
2015-02-05 21:31:06 -05:00
Trond Myklebust
6ae373394c NFSv4.1: Ask for no delegation on OPEN if using O_DIRECT
If we're using NFSv4.1, then we have the ability to let the server know
whether or not we believe that returning a delegation as part of our OPEN
request would be useful.
The feature needs to be used with care, since the client sending the request
doesn't necessarily know how other clients are using that file, and how
they may be affected by the delegation.
For this reason, our initial use of the feature will be to let the server
know when the client believes that handing out a delegation would not be
useful.
The first application for this function is when opening the file using
O_DIRECT.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-04 10:35:32 -05:00
Trond Myklebust
e2c63e091e Merge branch 'flexfiles'
* flexfiles: (53 commits)
  pnfs: lookup new lseg at lseg boundary
  nfs41: .init_read and .init_write can be called with valid pg_lseg
  pnfs: Update documentation on the Layout Drivers
  pnfs/flexfiles: Add the FlexFile Layout Driver
  nfs: count DIO good bytes correctly with mirroring
  nfs41: wait for LAYOUTRETURN before retrying LAYOUTGET
  nfs: add a helper to set NFS_ODIRECT_RESCHED_WRITES to direct writes
  nfs41: add NFS_LAYOUT_RETRY_LAYOUTGET to layout header flags
  nfs/flexfiles: send layoutreturn before freeing lseg
  nfs41: introduce NFS_LAYOUT_RETURN_BEFORE_CLOSE
  nfs41: allow async version layoutreturn
  nfs41: add range to layoutreturn args
  pnfs: allow LD to ask to resend read through pnfs
  nfs: add nfs_pgio_current_mirror helper
  nfs: only reset desc->pg_mirror_idx when mirroring is supported
  nfs41: add a debug warning if we destroy an unempty layout
  pnfs: fail comparison when bucket verifier not set
  nfs: mirroring support for direct io
  nfs: add mirroring support to pgio layer
  pnfs: pass ds_commit_idx through the commit path
  ...

Conflicts:
	fs/nfs/pnfs.c
	fs/nfs/pnfs.h
2015-02-03 16:01:27 -05:00
Tom Haynes
d67ae825a5 pnfs/flexfiles: Add the FlexFile Layout Driver
The flexfile layout is a new layout that extends the
file layout. It is currently being drafted as a specification at
https://datatracker.ietf.org/doc/draft-ietf-nfsv4-layout-types/

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Tao Peng <bergwolf@primarydata.com>
2015-02-03 11:06:52 -08:00
Peng Tao
aa8a45ee97 nfs41: wait for LAYOUTRETURN before retrying LAYOUTGET
Also take care to stop waiting if someone clears retry bit.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
2015-02-03 11:06:51 -08:00
Peng Tao
193e3aa2cc nfs41: introduce NFS_LAYOUT_RETURN_BEFORE_CLOSE
When it is set, generic pnfs would try to send layoutreturn right
before last close/delegation_return regard less NFS_LAYOUT_ROC is
set or not. LD can then make sure layoutreturn is always sent
rather than being omitted.

The difference against NFS_LAYOUT_RETURN is that
NFS_LAYOUT_RETURN_BEFORE_CLOSE does not block usage of the layout so
LD can set it and expect generic layer to try pnfs path at the
same time.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03 11:06:50 -08:00
Peng Tao
6c16605d6e nfs41: allow async version layoutreturn
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03 11:06:49 -08:00
Peng Tao
e736a5b98c nfs41: clear NFS_LAYOUT_RETURN if layoutreturn is sent or failed to send
So that pnfs path is not disabled for ever.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03 11:06:42 -08:00
Peng Tao
ce6ab4f238 nfs41: don't use a layout if it is marked for returning
And if we are to return the same type of layouts, don't bother
sending more layoutgets.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03 11:06:41 -08:00
Peng Tao
2c4b131dea nfs4: export nfs4_sequence_done
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03 11:06:36 -08:00
Peng Tao
cb04ad2a2b nfs4: pass slot table to nfs40_setup_sequence
flexclient needs this as there is no nfs_server to DS connection.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03 11:06:36 -08:00
Trond Myklebust
40dd4b7aee NFSv4.1: Optimise layout return-on-close
Optimise the layout return on close code by ensuring that

1) Add a check for whether we hold a layout before taking any spinlocks
2) Only take the spin lock once
3) Use nfs_state->state to speed up open file checks

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:48 -05:00
Trond Myklebust
b4019c0e21 NFSv4.1: Allow parallel LOCK/LOCKU calls
Note, however, that we still serialise on the open stateid if the lock
stateid is unconfirmed. Hopefully that will not prove too much of a
burden for first time locks; it should leave the ability to parallelise
OPENs unchanged, since they no longer call the serialisation primitives.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:48 -05:00
Trond Myklebust
c69899a17c NFSv4: Update of VFS byte range lock must be atomic with the stateid update
Ensure that we test the lock stateid remained unchanged while we were
updating the VFS tracking of the byte range lock. Have the process
replay the lock to the server if we detect that was not the case.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:47 -05:00
Trond Myklebust
425c1d4e5b NFSv4: Fix lock on-wire reordering issues
This patch ensures that the server cannot reorder our LOCK/LOCKU
requests if they are sent in parallel on the wire.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:47 -05:00
Trond Myklebust
6b447539aa NFSv4: Always do open_to_lock_owner if the lock stateid is uninitialised
The original text in RFC3530 was terribly confusing since it conflated
lockowners and lock stateids. RFC3530bis clarifies that you must use
open_to_lock_owner when there is no lock state for that file+lockowner
combination.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:46 -05:00
Trond Myklebust
39071e6fff NFSv4: Fix atomicity problems with lock stateid updates
When we update the lock stateid, we really do need to ensure that this is
done under the state->state_lock, and that we are indeed only updating
confirmed locks with a newer version of the same stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 17:27:41 -05:00
Trond Myklebust
63f5f796af NFSv4.1: Allow parallel OPEN/OPEN_DOWNGRADE/CLOSE
Remove the serialisation of OPEN/OPEN_DOWNGRADE and CLOSE calls for the
case of NFSv4.1 and newer.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-23 23:06:45 -05:00
Trond Myklebust
badc76dd0d NFSv4: Convert nfs_alloc_seqid() to return an ERR_PTR() if allocation fails
When we relax the sequencing on the NFSv4.1 OPEN/CLOSE code, we will want
to use the value NULL to indicate that no sequencing is needed.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-23 23:06:44 -05:00
Trond Myklebust
f95549cf24 NFSv4: More CLOSE/OPEN races
If an OPEN RPC call races with a CLOSE or OPEN_DOWNGRADE so that it
updates the nfs_state structure before the CLOSE/OPEN_DOWNGRADE has
a chance to do so, then we know that the state->flags need to be
recalculated from scratch.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-23 23:06:44 -05:00
Trond Myklebust
566fcec60b NFSv4: Fix an atomicity problem in CLOSE
If we are to remove the serialisation of OPEN/CLOSE, then we need to
ensure that the stateid sent as part of a CLOSE operation does not
change after we test the state in nfs4_close_prepare.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-23 19:22:39 -05:00
Trond Myklebust
4e379d36c0 NFSv4: Remove incorrect check in can_open_delegated()
Remove an incorrect check for NFS_DELEGATION_NEED_RECLAIM in
can_open_delegated(). We are allowed to cache opens even in
a situation where we're doing reboot recovery.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-05 19:40:54 -08:00
Trond Myklebust
ceb3a16c07 NFSv4: Cache the NFSv4/v4.1 client owner_id in the struct nfs_client
Ensure that we cache the NFSv4/v4.1 client owner_id so that we can
verify it when we're doing trunking detection.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-05 19:40:53 -08:00
Anna Schumaker
624bd5b7b6 nfs: Add DEALLOCATE support
This patch adds support for using the NFS v4.2 operation DEALLOCATE to
punch holes in a file.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-25 16:38:32 -05:00
Anna Schumaker
f4ac1674f5 nfs: Add ALLOCATE support
This patch adds support for using the NFS v4.2 operation ALLOCATE to
preallocate data in a file.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-25 16:38:32 -05:00
Peng Tao
4bd5a980de nfs41: fix nfs4_proc_layoutget error handling
nfs4_layoutget_release() drops layout hdr refcnt. Grab the refcnt
early so that it is safe to call .release in case nfs4_alloc_pages
fails.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Fixes: a47970ff78 ("NFSv4.1: Hold reference to layout hdr in layoutget")
Cc: stable@vger.kernel.org # 3.9+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 17:14:54 -05:00
Jan Kara
c1b69b1ca1 nfs: Remove dead case from nfs4_map_errors()
NFS4ERR_ACCESS has number 13 and thus is matched and returned
immediately at the beginning of nfs4_map_errors() and there's no point
in checking it later.

Coverity-id: 733891
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 12:48:14 -05:00
Trond Myklebust
c606bb8857 NFSv4: Ensure that we call FREE_STATEID when NFSv4.x stateids are revoked
NFSv4.x (x>0) requires us to call TEST_STATEID+FREE_STATEID if a stateid is
revoked. We will currently fail to do this if the stateid is a delegation.

http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-12 17:19:04 -05:00
Trond Myklebust
869f9dfa4d NFSv4: Fix races between nfs_remove_bad_delegation() and delegation return
Any attempt to call nfs_remove_bad_delegation() while a delegation is being
returned is currently a no-op. This means that we can end up looping
forever in nfs_end_delegation_return() if something causes the delegation
to be revoked.
This patch adds a mechanism whereby the state recovery code can communicate
to the delegation return code that the delegation is no longer valid and
that it should not be used when reclaiming state.
It also changes the return value for nfs4_handle_delegation_recall_error()
to ensure that nfs_end_delegation_return() does not reattempt the lock
reclaim before state recovery is done.

http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-12 17:19:04 -05:00
Trond Myklebust
0c116cadd9 NFSv4.1: nfs41_clear_delegation_stateid shouldn't trust NFS_DELEGATED_STATE
This patch removes the assumption made previously, that we only need to
check the delegation stateid when it matches the stateid on a cached
open.

If we believe that we hold a delegation for this file, then we must assume
that its stateid may have been revoked or expired too. If we don't test it
then our state recovery process may end up caching open/lock state in a
situation where it should not.
We therefore rename the function nfs41_clear_delegation_stateid as
nfs41_check_delegation_stateid, and change it to always run through the
delegation stateid test and recovery process as outlined in RFC5661.

http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-12 17:01:33 -05:00
Trond Myklebust
4dfd4f7af0 NFSv4: Ensure that we remove NFSv4.0 delegations when state has expired
NFSv4.0 does not have TEST_STATEID/FREE_STATEID functionality, so
unlike NFSv4.1, the recovery procedure when stateids have expired or
have been revoked requires us to just forget the delegation.

http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-12 17:00:09 -05:00
Anna Schumaker
e983120e92 NFS: SEEK is an NFS v4.2 feature
Somehow the nfs_v4_1_minor_ops had the NFS_CAP_SEEK flag set, enabling
SEEK over v4.1.  This is wrong, and can make servers crash.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-12 14:22:54 -05:00
Trond Myklebust
dca780016d Revert "NFS: nfs4_do_open should add negative results to the dcache."
This reverts commit 4fa2c54b51.
2014-11-04 19:53:50 -06:00
Trond Myklebust
7488cbc256 Revert "NFS: remove BUG possibility in nfs4_open_and_get_state"
This reverts commit f39c010479.
2014-11-04 19:53:49 -06:00
Trond Myklebust
b4b56796fe Merge branch 'client-4.2' into linux-next
Merge NFSv4.2 client SEEK implementation from Anna

* client-4.2: (55 commits)
  NFS: Implement SEEK
  NFSD: Implement SEEK
  NFSD: Add generic v4.2 infrastructure
  svcrdma: advertise the correct max payload
  nfsd: introduce nfsd4_callback_ops
  nfsd: split nfsd4_callback initialization and use
  nfsd: introduce a generic nfsd4_cb
  nfsd: remove nfsd4_callback.cb_op
  nfsd: do not clear rpc_resp in nfsd4_cb_done_sequence
  nfsd: fix nfsd4_cb_recall_done error handling
  nfsd4: clarify how grace period ends
  nfsd4: stop grace_time update at end of grace period
  nfsd: skip subsequent UMH "create" operations after the first one for v4.0 clients
  nfsd: set and test NFSD4_CLIENT_STABLE bit to reduce nfsdcltrack upcalls
  nfsd: serialize nfsdcltrack upcalls for a particular client
  nfsd: pass extra info in env vars to upcalls to allow for early grace period end
  nfsd: add a v4_end_grace file to /proc/fs/nfsd
  lockd: add a /proc/fs/lockd/nlm_end_grace file
  nfsd: reject reclaim request when client has already sent RECLAIM_COMPLETE
  nfsd: remove redundant boot_time parm from grace_done client tracking op
  ...
2014-09-30 17:22:02 -04:00
Trond Myklebust
72c23f0819 Merge branch 'bugfixes' into linux-next
* bugfixes:
  NFSv4.1: Fix an NFSv4.1 state renewal regression
  NFSv4: fix open/lock state recovery error handling
  NFSv4: Fix lock recovery when CREATE_SESSION/SETCLIENTID_CONFIRM fails
  NFS: Fabricate fscache server index key correctly
  SUNRPC: Add missing support for RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT
  nfs: fix duplicate proc entries
2014-09-30 17:21:41 -04:00
Andy Adamson
d1f456b0b9 NFSv4.1: Fix an NFSv4.1 state renewal regression
Commit 2f60ea6b8c ("NFSv4: The NFSv4.0 client must send RENEW calls if it holds a delegation") set the NFS4_RENEW_TIMEOUT flag in nfs4_renew_state, and does
not put an nfs41_proc_async_sequence call, the NFSv4.1 lease renewal heartbeat
call, on the wire to renew the NFSv4.1 state if the flag was not set.

The NFS4_RENEW_TIMEOUT flag is set when "now" is after the last renewal
(cl_last_renewal) plus the lease time divided by 3. This is arbitrary and
sometimes does the following:

In normal operation, the only way a future state renewal call is put on the
wire is via a call to nfs4_schedule_state_renewal, which schedules a
nfs4_renew_state workqueue task. nfs4_renew_state determines if the
NFS4_RENEW_TIMEOUT should be set, and the calls nfs41_proc_async_sequence,
which only gets sent if the NFS4_RENEW_TIMEOUT flag is set.
Then the nfs41_proc_async_sequence rpc_release function schedules
another state remewal via nfs4_schedule_state_renewal.

Without this change we can get into a state where an application stops
accessing the NFSv4.1 share, state renewal calls stop due to the
NFS4_RENEW_TIMEOUT flag _not_ being set. The only way to recover
from this situation is with a clientid re-establishment, once the application
resumes and the server has timed out the lease and so returns
NFS4ERR_BAD_SESSION on the subsequent SEQUENCE operation.

An example application:
open, lock, write a file.

sleep for 6 * lease (could be less)

ulock, close.

In the above example with NFSv4.1 delegations enabled, without this change,
there are no OP_SEQUENCE state renewal calls during the sleep, and the
clientid is recovered due to lease expiration on the close.

This issue does not occur with NFSv4.1 delegations disabled, nor with
NFSv4.0, with or without delegations enabled.

Signed-off-by: Andy Adamson <andros@netapp.com>
Link: http://lkml.kernel.org/r/1411486536-23401-1-git-send-email-andros@netapp.com
Fixes: 2f60ea6b8c (NFSv4: The NFSv4.0 client must send RENEW calls...)
Cc: stable@vger.kernel.org # 3.2.x
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-09-30 17:18:42 -04:00