336 Commits

Author SHA1 Message Date
Anna Schumaker
4e1ba532db NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return()
commit a421d218603ffa822a0b8045055c03eae394a7eb upstream.

Commit de144ff4234f changes _pnfs_return_layout() to call
pnfs_mark_matching_lsegs_return() passing NULL as the struct
pnfs_layout_range argument. Unfortunately,
pnfs_mark_matching_lsegs_return() doesn't check if we have a value here
before dereferencing it, causing an oops.

I'm able to hit this crash consistently when running connectathon basic
tests on NFS v4.1/v4.2 against Ontap.

Fixes: de144ff4234f ("NFSv4: Don't discard segments marked for return in _pnfs_return_layout()")
Cc: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-03 08:23:27 +02:00
Trond Myklebust
80e34f4957 NFSv4: Don't discard segments marked for return in _pnfs_return_layout()
commit de144ff4234f935bd2150108019b5d87a90a8a96 upstream.

If the pNFS layout segment is marked with the NFS_LSEG_LAYOUTRETURN
flag, then the assumption is that it has some reporting requirement
to perform through a layoutreturn (e.g. flexfiles layout stats or error
information).

Fixes: 6d597e175012 ("pnfs: only tear down lsegs that precede seqid in LAYOUTRETURN args")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:40:19 +02:00
Thomas Meyer
574940d9b4 NFS: Fix bool initialization/comparison
[ Upstream commit 6089dd0d731028531fb1148be9fd33274ff90da4 ]

Bool initializations should use true and false. Bool tests don't need
comparisons.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-14 16:31:07 -05:00
Trond Myklebust
1b9c9549b2 pNFS: Fix a deadlock when coalescing writes and returning the layout
[ Upstream commit 61f454e30c18a28924e96be12592c0d5e24bcc81 ]

Consider the following deadlock:

Process P1	Process P2		Process P3
==========	==========		==========
					lock_page(page)

		lseg = pnfs_update_layout(inode)

lo = NFS_I(inode)->layout
pnfs_error_mark_layout_for_return(lo)

		lock_page(page)

					lseg = pnfs_update_layout(inode)

In this scenario,
- P1 has declared the layout to be in error, but P2 holds a reference to
  a layout segment on that inode, so the layoutreturn is deferred.
- P2 is waiting for a page lock held by P3.
- P3 is asking for a new layout segment, but is blocked waiting
  for the layoutreturn.

The fix is to ensure that pnfs_error_mark_layout_for_return() does
not set the NFS_LAYOUT_RETURN flag, which blocks P3. Instead, we allow
the latter to call LAYOUTGET so that it can make progress and unblock
P2.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-24 11:00:21 +01:00
Trond Myklebust
b5e7b5ce7f pNFS: Fix use after free issues in pnfs_do_read()
[ Upstream commit 6aeafd05eca9bc8ab6b03d7e56d09ffd18190f44 ]

The assumption should be that if the caller returns PNFS_ATTEMPTED, then hdr
has been consumed, and so we should not be testing hdr->task.tk_status.
If the caller returns PNFS_TRY_AGAIN, then we need to recoalesce and
free hdr.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-24 11:00:15 +01:00
Scott Mayhew
e1df8c682d nfs/pnfs: fix nfs_direct_req ref leak when i/o falls back to the mds
commit ba4a76f703ab7eb72941fdaac848502073d6e9ee upstream.

Currently when falling back to doing I/O through the MDS (via
pnfs_{read|write}_through_mds), the client frees the nfs_pgio_header
without releasing the reference taken on the dreq
via pnfs_generic_pg_{read|write}pages -> nfs_pgheader_init ->
nfs_direct_pgio_init.  It then takes another reference on the dreq via
nfs_generic_pg_pgios -> nfs_pgheader_init -> nfs_direct_pgio_init and
as a result the requester will become stuck in inode_dio_wait.  Once
that happens, other processes accessing the inode will become stuck as
well.

Ensure that pnfs_read_through_mds() and pnfs_write_through_mds() clean
up correctly by calling hdr->completion_ops->completion() instead of
calling hdr->release() directly.

This can be reproduced (sometimes) by performing "storage failover
takeover" commands on NetApp filer while doing direct I/O from a client.

This can also be reproduced using SystemTap to simulate a failure while
doing direct I/O from a client (from Dave Wysochanski
<dwysocha@redhat.com>):

stap -v -g -e 'probe module("nfs_layout_nfsv41_files").function("nfs4_fl_prepare_ds").return { $return=NULL; exit(); }'

Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: 1ca018d28d ("pNFS: Fix a memory leak when attempted pnfs fails")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-17 13:21:14 +01:00
Trond Myklebust
a70912a6bf NFS: Fix 2 use after free issues in the I/O code
commit 196639ebbe63a037fe9a80669140bd292d8bcd80 upstream.

The writeback code wants to send a commit after processing the pages,
which is why we want to delay releasing the struct path until after
that's done.

Also, the layout code expects that we do not free the inode before
we've put the layout segments in pnfs_writehdr_free() and
pnfs_readhdr_free()

Fixes: 919e3bd9a875 ("NFS: Ensure we commit after writeback is complete")
Fixes: 4714fb51fd03 ("nfs: remove pgio_header refcount, related cleanup")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-13 14:13:37 -07:00
Trond Myklebust
4c4d4bec6c pNFS: Fix race in pnfs_wait_on_layoutreturn
commit ee284e35d8c71bf5d4d807eaff6f67a17134b359 upstream.

We must put the task to sleep while holding the inode->i_lock in order
to ensure atomicity with the test for NFS_LAYOUT_RETURN.

Fixes: 500d701f336b ("NFS41: make close wait for layoutreturn")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19 20:18:05 +01:00
Trond Myklebust
ba15defe18 pNFS: Fix a deadlock between read resends and layoutreturn
commit 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe upstream.

We must not call nfs_pageio_init_read() on a new nfs_pageio_descriptor
while holding a reference to a layout segment, as that can deadlock
pnfs_update_layout().

Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-09 08:32:25 +01:00
Trond Myklebust
e523ce8c99 pNFS: Clear NFS_LAYOUT_RETURN_REQUESTED when invalidating the layout stateid
commit ae5a459d5f65c3e83f3e14068dde5fb9c9d81807 upstream.

We must ensure that we don't schedule a layoutreturn if the layout stateid
has been marked as invalid.

Fixes: 2a59a0411671e ("pNFS: Fix pnfs_set_layout_stateid() to clear...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-09 08:32:24 +01:00
Trond Myklebust
f32659df6e pNFS: Don't clear the layout stateid if a layout return is outstanding
commit 7b650994ab07434ae58a247dc9ac87d2488ca75c upstream.

If we no longer hold any layout segments, we're normally expected to
consider the layout stateid to be invalid. However we cannot assume this
if we're about to, or in the process of sending a layoutreturn.

Fixes: 334a8f37115b ("pNFS: Don't forget the layout stateid if...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-09 08:32:24 +01:00
Trond Myklebust
24b049fa0c pNFS: On error, do not send LAYOUTGET until the LAYOUTRETURN has completed
commit 6604b203fb6394ed1f24c21bfa3c207e5ae8e461 upstream.

If there is an I/O error, we should not call LAYOUTGET until the
LAYOUTRETURN that reports the error is complete.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-09 08:32:24 +01:00
Anna Schumaker
192747166a NFS: Don't print a pNFS error if we aren't using pNFS
We used to check for a valid layout type id before verifying pNFS flags
as an indicator for if we are using pNFS.  This changed in 3132e49ece
with the introduction of multiple layout types, since now we are passing
an array of ids instead of just one.  Since then, users have been seeing
a KERN_ERR printk show up whenever mounting NFS v4 without pNFS.  This
patch restores the original behavior of exiting set_pnfs_layoutdriver()
early if we aren't using pNFS.

Fixes 3132e49ece ("pnfs: track multiple layout types in fsinfo
structure")
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-11-07 16:11:30 -05:00
Trond Myklebust
bfc505ded0 pNFS: Fix atime updates on pNFS clients
Fix the code so that we always mark the atime as invalid in nfs4_read_done().
Currently, the expectation appears to be that the pNFS drivers should always
do this, with the result that most of them don't.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-09-27 14:35:36 -04:00
Jeff Layton
ca440c383a pnfs: add a new mechanism to select a layout driver according to an ordered list
Currently, the layout driver selection code always chooses the first one
from the list. That's not really ideal however, as the server can send
the list of layout types in any order that it likes. It's up to the
client to select the best one for its needs.

This patch adds an ordered list of preferred driver types and has the
selection code sort the list of available layout drivers according to it.
Any unrecognized layout type is sorted to the end of the list.

For now, the order of preference is hardcoded, but it should be possible
to make this configurable in the future.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-09-19 13:11:13 -04:00
Jeff Layton
3132e49ece pnfs: track multiple layout types in fsinfo structure
Current NFSv4.1/pNFS client assumes that MDS supports only one layout
type. While it's true for most existing servers, nevertheless, this can
be change in the near future.

For now, this patch just plumbs in the ability to track a list of
layouts in the fsinfo structure. The existing behavior of the client
is preserved, by having it just select the first entry in the list.

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-09-19 13:08:35 -04:00
Trond Myklebust
334a8f3711 pNFS: Don't forget the layout stateid if there are outstanding LAYOUTGETs
If there are outstanding LAYOUTGET rpc calls, then we want to ensure that
we keep the layout stateid around so we that don't inadvertently pick up
an old/misordered sequence id.
The race is as follows:

Client				Server
======				======
LAYOUTGET(seqid)
LAYOUTGET(seqid)
				return LAYOUTGET(seqid+1)
				return LAYOUTGET(seqid+2)
process LAYOUTGET(seqid+2)
	forget layout
process LAYOUTGET(seqid+1)

If it forgets the layout stateid before processing seqid+1, then
the client will not check the layout->plh_barrier, and so will set
the stateid with seqid+1.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-09-04 12:59:00 -04:00
Trond Myklebust
2a59a04116 pNFS: Fix pnfs_set_layout_stateid() to clear NFS_LAYOUT_INVALID_STID
If the layout was marked as invalid, we want to ensure to initialise
the layout header fields correctly.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-09-03 12:10:37 -04:00
Trond Myklebust
bf0291dd22 pNFS: Ensure LAYOUTGET and LAYOUTRETURN are properly serialised
According to RFC5661, the client is responsible for serialising
LAYOUTGET and LAYOUTRETURN to avoid ambiguity. Consider the case
where we send both in parallel.

Client					Server
======					======
LAYOUTGET(seqid=X)
LAYOUTRETURN(seqid=X)
					LAYOUTGET return seqid=X+1
					LAYOUTRETURN return seqid=X+2
Process LAYOUTRETURN
          Forget layout stateid
Process LAYOUTGET
          Set seqid=X+1

The client processes the layoutget/layoutreturn in the wrong order,
and since the result of the layoutreturn was to clear the only
existing layout segment, the client forgets the layout stateid.

When the LAYOUTGET comes in, it is treated as having a completely
new stateid, and so the client sets the wrong sequence id...

Fix is to check if there are outstanding LAYOUTGET requests
before we send the LAYOUTRETURN (note that LAYOUGET will already
wait if it sees an outstanding LAYOUTRETURN).

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-09-03 12:10:37 -04:00
Trond Myklebust
b88fa69eaa pNFS: The client must not do I/O to the DS if it's lease has expired
Ensure that the client conforms to the normative behaviour described in
RFC5661 Section 12.7.2: "If a client believes its lease has expired,
it MUST NOT send I/O to the storage device until it has validated its
lease."

So ensure that we wait for the lease to be validated before using
the layout.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.20+
2016-08-23 11:27:01 -04:00
Trond Myklebust
9a0fe86745 pNFS: Handle NFS4ERR_OLD_STATEID correctly in LAYOUTSTAT calls
We normally want to update the stateid and then retry,

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-08-19 16:27:31 -04:00
Trond Myklebust
668f455dac Merge branch 'pnfs' 2016-07-24 17:08:59 -04:00
Trond Myklebust
362745268c Merge branch 'writeback' 2016-07-24 17:08:31 -04:00
Trond Myklebust
01d7b29f0e pNFS: Remove redundant smp_mb() from pnfs_init_lseg()
It's not visible yet, and won't be until after we grab the inode->i_lock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:43 -04:00
Trond Myklebust
119cef97a4 pNFS: Cleanup - do layout segment initialisation in one place
...instead of splitting the initialisation over init_lseg() and
pnfs_layout_process().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:42 -04:00
Trond Myklebust
28c1acffea pNFS: Remove redundant stateid invalidation
The layout stateid will be invalidated once it holds no more layout
segments anyway.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:42 -04:00
Trond Myklebust
f71dfe8fc9 pNFS: Remove redundant pnfs_mark_layout_returned_if_empty()
That's already being taken care of in pnfs_layout_remove_lseg().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:41 -04:00
Trond Myklebust
d9b61708fe pNFS: Clear the layout metadata if the server changed the layout stateid
If the server changed the layout stateid's "other" field, then
we should treat the old layout as being completely gone. In that
case, we want to clear the metadata such as scheduled layoutreturns.

Do this by calling pnfs_mark_layout_stateid_invalid().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:41 -04:00
Trond Myklebust
5f46be049b pNFS: Cleanup - don't open code pnfs_mark_layout_stateid_invalid()
Ensure nfs42_layoutstat_done() layoutget don't open code layout stateid
invalidation.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:40 -04:00
Trond Myklebust
e036f46453 NFS: pnfs_mark_matching_lsegs_return() should match the layout sequence id
When determining which layout segments to return, we do want
pnfs_mark_matching_lsegs_return to check that they match the layout
sequence id. This ensures that we don't waste time if the server
is replaying a layout recall that has already been satisfied.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:40 -04:00
Trond Myklebust
2d6cf5ab0b pNFS: Do not set plh_return_seq for non-callback related layoutreturns
In cases where we need to send a layoutreturn in order to propagate
an error, we should not tie that to a specific layout stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:39 -04:00
Trond Myklebust
e5fd1904b8 pNFS: Ensure layoutreturn acts as a completion for layout callbacks
When we return NFS_OK to the CB_LAYOUTRECALL, we are required to
send a layoutreturn that "completes" that layout recall request, using
the correct stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:39 -04:00
Trond Myklebust
ecebb80bf3 pNFS: Always update the layout barrier seqid on LAYOUTGET
Currently, pnfs_set_layout_stateid() will update the layout sequence
id barrier only if the stateid itself is newer than the current
layout stateid. However in a situation where multiple LAYOUTGET calls
and a LAYOUTRETURN raced, it is entirely possible for one of the
LAYOUTGET to set the current stateid to something newer than the
LAYOUTRETURN that needs to set the barrier.

The fix is to allow the "update_barrier" flag to force a check as to
whether or not the barrier needs to be updated.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:38 -04:00
Trond Myklebust
13bede18de pNFS: Always update the layout stateid if NFS_LAYOUT_INVALID_STID is set
If the layout stateid is invalid, then pnfs_set_layout_stateid() must
always initialise it.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 16:16:25 -04:00
Trond Myklebust
8e0acf9046 pNFS: Clear the layout return tracking on layout reinitialisation
Ensure that we don't carry over layoutreturn info from a previous
incarnation of this layout.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24 12:51:49 -04:00
Trond Myklebust
66b53f3258 pNFS: Handle NFS4ERR_RECALLCONFLICT correctly in LAYOUTGET
Instead of giving up altogether and falling back to doing I/O
through the MDS, which may make the situation worse, wait for
2 lease periods for the callback to resolve itself, and then
try destroying the existing layout.

Only if this was an attempt at getting a first layout, do we
give up altogether, as the server is clearly crazy.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
2016-07-19 16:23:22 -04:00
Trond Myklebust
e85d7ee420 pNFS: Separate handling of NFS4ERR_LAYOUTTRYLATER and RECALLCONFLICT
They are not the same error, and need to be handled differently.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
2016-07-19 16:23:22 -04:00
Trond Myklebust
56b38a1f7c pNFS: Fix post-layoutget error handling in pnfs_update_layout()
The non-retry error path is currently broken and ends up releasing the
reference to the layout twice. It also can end up clearing the
NFS_LAYOUT_FIRST_LAYOUTGET flag twice, causing a race.

In addition, the retry path will fail to decrement the plh_outstanding
counter.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
2016-07-19 16:22:47 -04:00
Trond Myklebust
2e18d4d822 pNFS: Files and flexfiles always need to commit before layoutcommit
So ensure that we mark the layout for commit once the write is done,
and then ensure that the commit to ds is finished before sending
layoutcommit.

Note that by doing this, we're able to optimise away the commit
for the case of servers that don't need layoutcommit in order to
return updated attributes.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-05 19:08:01 -04:00
Trond Myklebust
2d148c7e84 NFSv4.1/pnfs: Mark the layout stateid invalid when all segments are removed
According to RFC5661, section 12.5.3. the layout stateid is no longer
valid once the client no longer holds any layout segments. Ensure that
we mark it invalid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-24 12:01:00 -04:00
Trond Myklebust
e5241e4388 NFSv4.1/pnfs: Add sparse lock annotations for pnfs_find_alloc_layout
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-24 12:01:00 -04:00
Trond Myklebust
67a3b72146 NFSv4.1/pnfs: Layout stateids start out as being invalid
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-24 12:01:00 -04:00
Tom Haynes
c7d73af2d2 pnfs: pnfs_update_layout needs to consider if strict iomode checking is on
As flexfiles has FF_FLAGS_NO_READ_IO, there is a need to generically
support enforcing that a IOMODE_RW segment will not allow READ I/O.

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-26 08:40:56 -04:00
Jeff Layton
1b3c6d07e2 pnfs: make pnfs_layout_process more robust
It can return NULL if layoutgets are blocked currently. Fix it to return
-EAGAIN in that case, so we can properly handle it in pnfs_update_layout.

Also, clean up and simplify the error handling -- eliminate "status" and
just use "lseg".

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:13 -04:00
Jeff Layton
183d9e7b11 pnfs: rework LAYOUTGET retry handling
There are several problems in the way a stateid is selected for a
LAYOUTGET operation:

We pick a stateid to use in the RPC prepare op, but that makes
it difficult to serialize LAYOUTGETs that use the open stateid. That
serialization is done in pnfs_update_layout, which occurs well before
the rpc_prepare operation.

Between those two events, the i_lock is dropped and reacquired.
pnfs_update_layout can find that the list has lsegs in it and not do any
serialization, but then later pnfs_choose_layoutget_stateid ends up
choosing the open stateid.

This patch changes the client to select the stateid to use in the
LAYOUTGET earlier, when we're searching for a usable layout segment.
This way we can do it all while holding the i_lock the first time, and
ensure that we serialize any LAYOUTGET call that uses a non-layout
stateid.

This also means a rework of how LAYOUTGET replies are handled, as we
must now get the latest stateid if we want to retransmit in response
to a retryable error.

Most of those errors boil down to the fact that the layout state has
changed in some fashion. Thus, what we really want to do is to re-search
for a layout when it fails with a retryable error, so that we can avoid
reissuing the RPC at all if possible.

While the LAYOUTGET RPC is async, the initiating thread always waits for
it to complete, so it's effectively synchronous anyway. Currently, when
we need to retry a LAYOUTGET because of an error, we drive that retry
via the rpc state machine.

This means that once the call has been submitted, it runs until it
completes. So, we must move the error handling for this RPC out of the
rpc_call_done operation and into the caller.

In order to handle errors like NFS4ERR_DELAY properly, we must also
pass a pointer to the sliding timeout, which is now moved to the stack
in pnfs_update_layout.

The complicating errors are -NFS4ERR_RECALLCONFLICT and
-NFS4ERR_LAYOUTTRYLATER, as those involve a timeout after which we give
up and return NULL back to the caller. So, there is some special
handling for those errors to ensure that the layers driving the retries
can handle that appropriately.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:12 -04:00
Jeff Layton
83026d80a1 pnfs: lift retry logic from send_layoutget to pnfs_update_layout
If we get back something like NFS4ERR_OLD_STATEID, that will be
translated into -EAGAIN, and the do/while loop in send_layoutget
will drive the call again.

This is not quite what we want, I think. An error like that is a
sign that something has changed. That something could have been a
concurrent LAYOUTGET that would give us a usable lseg.

Lift the retry logic into pnfs_update_layout instead. That allows
us to redo the layout search, and may spare us from having to issue
an RPC.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:12 -04:00
Jeff Layton
d03ab29dbb pnfs: fix bad error handling in send_layoutget
Currently, the code will clear the fail bit if we get back a fatal
error. I don't think that's correct -- we want to clear that bit
if we do not get a fatal error.

Fixes: 0bcbf039f6 (nfs: handle request add failure properly)
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:11 -04:00
Jeff Layton
6d597e1750 pnfs: only tear down lsegs that precede seqid in LAYOUTRETURN args
LAYOUTRETURN is "special" in that servers and clients are expected to
work with old stateids. When the client sends a LAYOUTRETURN with an old
stateid in it then the server is expected to only tear down layout
segments that were present when that seqid was current. Ensure that the
client handles its accounting accordingly.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:10 -04:00
Jeff Layton
3982a6a2d0 pnfs: keep track of the return sequence number in pnfs_layout_hdr
When we want to selectively do a LAYOUTRETURN, we need to specify a
stateid that represents most recent layout acquisition that is to be
returned.

When we mark a layout stateid to be returned, we update the return
sequence number in the layout header with that value, if it's newer
than the existing one. Then, when we go to do a LAYOUTRETURN on
layout header put, we overwrite the seqid in the stateid with the
saved one, and then zero it out.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:10 -04:00
Jeff Layton
6675528380 pnfs: record sequence in pnfs_layout_segment when it's created
In later patches, we're going to teach the client to be more selective
about how it returns layouts. This means keeping a record of what the
stateid's seqid was at the time that the server handed out a layout
segment.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17 15:48:09 -04:00