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If the old layout was recalled, and we returned NFS4ERR_NOMATCHINGLAYOUT
then we need to wait for all outstanding layoutget calls to complete
before we can send a new one.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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If a layout segment is carrying layoutstats or layout error information,
then we always want to return it rather than using a forgetful model.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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If a layout has been recalled, then we should fire off a layoutreturn as
soon as all the layout segments that match the recall have been retired.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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RFC5661 doesn't state directly that the client should update the layout
stateid if it returns NFS4ERR_NOMATCHING_LAYOUT in response to a recall,
however it does state that this error will "cleanly indicate completion"
on par with returning the layout. For this reason, we assume that the
client should update the layout stateid. The Linux pNFS server definitely
does expect this behaviour.
However, if the client replies NFS4ERR_DELAY, then it is stating that
the recall was not processed, so it would be very wrong to update the
layout stateid.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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If there are layout segments that are marked for return, then we need
to ensure that pnfs_mark_matching_lsegs_return() does not just
silently discard them, but it should tell the caller that there is a
layoutreturn scheduled.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Before this patch gfs2_rgrp_ondisk2lvb was called after every call
to gfs2_rgrp_out. This patch just calls it directly from within
gfs2_rgrp_out, and moves the function to be before it so we don't
need a function prototype.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
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Fixes: 72ecad22d9f1 ("block: support a full bio worth of IO for simplified bdev direct-io")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The barrier mount options have been no-ops and deprecated since
4cf4573 xfs: deprecate barrier/nobarrier mount option
i.e. kernel 4.10 / December 2016, with a stated deprecation schedule
after v4.15. Should be fair game to remove them now.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Replace the IRELE macro with a proper function so that we can do proper
typechecking and so that we can stop open-coding iput in scrub, which
means that we'll be able to ftrace inode lifetimes going through scrub
correctly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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Nobody uses this macro, get rid of it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
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Once xfs_defer_finish() has completed all deferred operations, it
checks the dirty state of the transaction and rolls it once more to
return a clean transaction for the caller. This primarily to cover
the case where repeated xfs_defer_finish() calls are made in a loop
and we need to make sure that the caller starts the next iteration
with a clean transaction. Otherwise we risk transaction reservation
overrun.
This final transaction roll is not required in the transaction
commit path, however, because the transaction is immediately
committed and freed after dfops completion. Refactor the final roll
into a separate helper such that we can avoid it in the transaction
commit path. Lift the dfops reset as well so dfops remains valid
until after the last call to xfs_defer_trans_roll(). The reset is
also unnecessary in the transaction commit path because the
transaction is about to complete.
This eliminates unnecessary regrants of transactions where the
associated transaction roll can be replaced by a transaction commit.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Every caller of xfs_defer_finish() now passes the transaction and
its associated ->t_dfops. The xfs_defer_ops parameter is therefore
no longer necessary and can be removed.
Since most xfs_defer_finish() callers also have to consider
xfs_defer_cancel() on error, update the latter to also receive the
transaction for consistency. The log recovery code contains an
outlier case that cancels a dfops directly without an available
transaction. Retain an internal wrapper to support this outlier case
for the time being.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Each xfs_defer_init() call in the xattr code uses the internal dfops
reference. In addition, a successful xfs_defer_finish() always
returns with a reset xfs_defer_ops structure.
Given that along with the fact that every xfs_defer_init() call in
the xattr code is followed up by an xfs_defer_finish(), the former
calls are no longer necessary and can be removed.
Note that the xfs_defer_init() call in the remote value copy loop of
xfs_attr_rmtval_set() is not followed by a finish, but the dfops is
unused in this instance.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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At this point, the transaction subsystem completely manages deferred
items internally such that the common and boilerplate
xfs_trans_alloc() -> xfs_defer_init() -> xfs_defer_finish() ->
xfs_trans_commit() sequence can be replaced with a simple
transaction allocation and commit.
Remove all such boilerplate deferred ops code. In doing so, we
change each case over to use the dfops in the transaction and
specifically eliminate:
- The on-stack dfops and associated xfs_defer_init() call, as the
internal dfops is initialized on transaction allocation.
- xfs_bmap_finish() calls that precede a final xfs_trans_commit() of
a transaction.
- xfs_defer_cancel() calls in error handlers that precede a
transaction cancel.
The only deferred ops calls that remain are those that are
non-deterministic with respect to the final commit of the associated
transaction or are open-coded due to special handling.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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bmap and refcount intent processing associates a dfops from the
caller with a local transaction to collect all deferred items for
post-processing. Use the internal dfops in both of these functions
and move the deferred items to the parent dfops before the
transaction commits.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Remove the unnecessary on-stack dfops structure and use the internal
transaction dfops instead. The lower level xattr code already
appropriately accesses ->t_dfops throughout.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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All callers either explicitly initialize a dfops or pass a
transaction with an internal dfops. Drop the hacky old dfops
replacement logic and use the one associated with the transaction.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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The dfops structure used by multi-transaction operations is
typically stored on the stack and carried around by the associated
transaction. The lifecycle of dfops does not quite match that of the
transaction, but they are tightly related in that the former depends
on the latter.
The relationship of these objects is tight enough that we can avoid
the cumbersome boilerplate code required in most cases to manage
them separately by just embedding an xfs_defer_ops in the
transaction itself. This means that a transaction allocation returns
with an initialized dfops, a transaction commit finishes pending
deferred items before the tx commit, a transaction cancel cancels
the dfops before the transaction and a transaction dup operation
transfers the current dfops state to the new transaction.
The dup operation is slightly complicated by the fact that we can no
longer just copy a dfops pointer from the old transaction to the new
transaction. This is solved through a dfops move helper that
transfers the pending items and other dfops state across the
transactions. This also requires that transaction rolling code
always refer to the transaction for the current dfops reference.
Finally, to facilitate incremental conversion to the internal dfops
and continue to support the current external dfops mode of
operation, create the new ->t_dfops_internal field with a layer of
indirection. On allocation, ->t_dfops points to the internal dfops.
This state is overridden by callers who re-init a local dfops on the
transaction. Once ->t_dfops is overridden, the external dfops
reference is maintained as the transaction rolls.
This patch adds the fundamental ability to support an internal
dfops. All codepaths that perform deferred processing continue to
override the internal dfops until they are converted over in
subsequent patches.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Both structures have holes due to member alignment. Move dop_low to
the end of xfs_defer ops to sanitize the cache line alignment and
move t_flags to save 8 bytes in xfs_trans.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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xfs_defer_init() is currently used in two particular situations. The
first and most obvious case is raw initialization of an
xfs_defer_ops struct. The other case is partial reinit of
xfs_defer_ops on reuse due to iteration.
Most instances of the first case will be replaced by a single init
of a dfops embedded in the transaction. Init calls are still
technically required for the second case because the dfops may have
low space mode enabled or have joined items that need to be reset
before the dfops should be reused.
Since the current dfops usage expects either a final transaction
commit after xfs_defer_finish() or xfs_defer_init() if dfops is to
be reused, we can shift some of the init logic into
xfs_defer_finish() such that the latter returns with a reinitialized
dfops. This eliminates the second dependency noted above such that a
dfops is immediately ready for reuse after an xfs_defer_finish()
without the need to change any calling code.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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dop_committed is set when deferred item processing rolls the
transaction at least once, but is only ever accessed in tracepoints.
The transaction roll/commit events are already available via
independent tracepoints, so remove the otherwise unused field.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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xfs_defer_finish() has a couple quirks that are not safe with
respect to the upcoming internal dfops functionality. First,
xfs_defer_finish() attaches the passed in dfops structure to
->t_dfops and caches and restores the original value. Second, it
continues to use the initial dfops reference before and after the
transaction roll.
These behaviors assume that dop is an independent memory allocation
from the transaction itself, which may not always be true once
transactions begin to use an embedded dfops structure. In the latter
model, dfops processing creates a new xfs_defer_ops structure with
each transaction and the associated state is migrated across to the
new transaction.
Fix up xfs_defer_finish() to handle the possibility of the current
dfops changing after a transaction roll. Since ->t_dfops is used
unconditionally in this path, it is no longer necessary to
attach/restore ->t_dfops and pass it explicitly down to
xfs_defer_trans_roll(). Update dop in the latter function and the
caller to ensure that it always refers to the current dfops
structure.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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The xattr remote value set/remove handlers both clear args.trans in
the error path without having cancelled the transaction. This leaks
the transaction, causes warnings around returning to userspace with
locks held and leads to system lockups or other general problems.
The higher level xfs_attr_[set|remove]() functions already detect
and cancel args.trans when set in the error path. Drop the NULL
assignments from the rmtval handlers and allow the callers to clean
up the transaction correctly.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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xlog_finish_defer_ops() processes the deferred operations collected
over the entire intent recovery sequence. We can't xfs_defer_init()
here because the dfops is already populated. Attach it manually and
eliminate the last caller of xfs_defer_finish() that doesn't pass
->t_dfops.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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xfs_itruncate_extents[_flags]() uses a local dfops with a
transaction provided by the caller. It uses hacky ->t_dfops
replacement logic to avoid stomping over an already populated
->t_dfops.
The latter never occurs for current callers and the logic itself is
not really appropriate. Clean this up by updating all callers to
initialize a dfops and to use that down in xfs_itruncate_extents().
This more closely resembles the upcoming logic where dfops will be
embedded within the transaction. We can also replace the
xfs_defer_init() in the xfs_itruncate_extents_flags() loop with an
assert. Both dfops and firstblock should be in a valid state
after xfs_defer_finish() and the inode joined to the dfops is fixed
throughout the loop.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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The 'bufs' array contains 'pipe->buffers' elements, but the
fuse_dev_splice_write() uses only 'pipe->nrbufs' elements.
So reduce the allocation size to 'pipe->nrbufs' elements.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The amount of pipe->buffers is basically controlled by userspace by
fcntl(... F_SETPIPE_SZ ...) so it could be large. High order allocations
could be slow (if memory is heavily fragmented) or may fail if the order
is larger than PAGE_ALLOC_COSTLY_ORDER.
Since the 'bufs' doesn't need to be physically contiguous, use
the kvmalloc_array() to allocate memory. If high order
page isn't available, the kvamalloc*() will fallback to 0-order.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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All of fuse uses 64-bit timestamps with the exception of the
fuse_change_attributes(), so let's convert this one as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Use new return type vm_fault_t for fault handler in struct
vm_operations_struct. For now, this is just documenting that the function
returns a VM_FAULT value rather than an errno. Once all instances are
converted, vm_fault_t will become a distinct type.
commit 1c8f422059ae ("mm: change return type to vm_fault_t")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The above error path returns with page unlocked, so this place seems also
to behave the same.
Fixes: f8dbdf81821b ("fuse: rework fuse_readpages()")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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fuse_dev_splice_write() reads pipe->buffers to determine the size of
'bufs' array before taking the pipe_lock(). This is not safe as
another thread might change the 'pipe->buffers' between the allocation
and taking the pipe_lock(). So we end up with too small 'bufs' array.
Move the bufs allocations inside pipe_lock()/pipe_unlock() to fix this.
Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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If parallel dirops are enabled in FUSE_INIT reply, then first operation may
leave fi->mutex held.
Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com>
Fixes: 5c672ab3f0ee ("fuse: serialize dirops by default")
Cc: <stable@vger.kernel.org> # v4.7
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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syzbot is hitting NULL pointer dereference at process_init_reply().
This is because deactivate_locked_super() is called before response for
initial request is processed.
Fix this by aborting and waiting for all requests (including FUSE_INIT)
before resetting fc->sb.
Original patch by Tetsuo Handa <penguin-kernel@I-love.SKAURA.ne.jp>.
Reported-by: syzbot <syzbot+b62f08f4d5857755e3bc@syzkaller.appspotmail.com>
Fixes: e27c9d3877a0 ("fuse: fuse: add time_gran to INIT_OUT")
Cc: <stable@vger.kernel.org> # v3.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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fuse_abort_conn() does not guarantee that all async requests have actually
finished aborting (i.e. their ->end() function is called). This could
actually result in still used inodes after umount.
Add a helper to wait until all requests are fully done. This is done by
looking at the "num_waiting" counter. When this counter drops to zero, we
can be sure that no more requests are outstanding.
Fixes: 0d8e84b0432b ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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fuse_dev_release() assumes that it's the only one referencing the
fpq->processing list, but that's not true, since fuse_abort_conn() can be
doing the same without any serialization between the two.
Fixes: c3696046beb3 ("fuse: separate pqueue for clones")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Refcounting of request is broken when fuse_abort_conn() is called and
request is on the fpq->io list:
- ref is taken too late
- then it is not dropped
Fixes: 0d8e84b0432b ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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To speed up the common case of appending to a file,
gfs2_write_alloc_required presumes that writing beyond the end of a file
will always require additional blocks to be allocated. This assumption
is incorrect for preallocates files, but there are no negative
consequences as long as *some* space is still left on the filesystem.
One special file that always has some space preallocated beyond the end
of the file is the rindex: when growing a filesystem, gfs2_grow adds one
or more new resource groups and appends records describing those
resource groups to the rindex; the preallocated space ensures that this
is always possible.
However, when a filesystem is completely full, gfs2_write_alloc_required
will indicate that an additional allocation is required, and appending
the next record to the rindex will fail even though space for that
record has already been preallocated. To fix that, skip the incorrect
optimization in gfs2_write_alloc_required, but for the rindex only.
Other writes to preallocated space beyond the end of the file are still
allowed to fail on completely full filesystems.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull fscache/cachefiles fixes from David Howells:
- Allow cancelled operations to be queued so they can be cleaned up.
- Fix a refcounting bug in the monitoring of reads on backend files
whereby a race can occur between monitor objects being listed for
work, the work processing being queued and the work processor running
and destroying the monitor objects.
- Fix a ref overput in object attachment, whereby a tentatively
considered object is put in error handling without first being 'got'.
- Fix a missing clear of the CACHEFILES_OBJECT_ACTIVE flag whereby an
assertion occurs when we retry because it seems the object is now
active.
- Wait rather BUG'ing on an object collision in the depths of
cachefiles as the active object should be being cleaned up - also
depends on the one above.
* tag 'fscache-fixes-20180725' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
cachefiles: Wait rather than BUG'ing on "Unexpected object collision"
cachefiles: Fix missing clear of the CACHEFILES_OBJECT_ACTIVE flag
fscache: Fix reference overput in fscache_attach_object() error handling
cachefiles: Fix refcounting bug in backing-file read monitoring
fscache: Allow cancelled operations to be enqueued
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If we meet a conflicting object that is marked FSCACHE_OBJECT_IS_LIVE in
the active object tree, we have been emitting a BUG after logging
information about it and the new object.
Instead, we should wait for the CACHEFILES_OBJECT_ACTIVE flag to be cleared
on the old object (or return an error). The ACTIVE flag should be cleared
after it has been removed from the active object tree. A timeout of 60s is
used in the wait, so we shouldn't be able to get stuck there.
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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In cachefiles_mark_object_active(), the new object is marked active and
then we try to add it to the active object tree. If a conflicting object
is already present, we want to wait for that to go away. After the wait,
we go round again and try to re-mark the object as being active - but it's
already marked active from the first time we went through and a BUG is
issued.
Fix this by clearing the CACHEFILES_OBJECT_ACTIVE flag before we try again.
Analysis from Kiran Kumar Modukuri:
[Impact]
Oops during heavy NFS + FSCache + Cachefiles
CacheFiles: Error: Overlong wait for old active object to go away.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000002
CacheFiles: Error: Object already active kernel BUG at
fs/cachefiles/namei.c:163!
[Cause]
In a heavily loaded system with big files being read and truncated, an
fscache object for a cookie is being dropped and a new object being
looked. The new object being looked for has to wait for the old object
to go away before the new object is moved to active state.
[Fix]
Clear the flag 'CACHEFILES_OBJECT_ACTIVE' for the new object when
retrying the object lookup.
[Testcase]
Have run ~100 hours of NFS stress tests and have not seen this bug recur.
[Regression Potential]
- Limited to fscache/cachefiles.
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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When a cookie is allocated that causes fscache_object structs to be
allocated, those objects are initialised with the cookie pointer, but
aren't blessed with a ref on that cookie unless the attachment is
successfully completed in fscache_attach_object().
If attachment fails because the parent object was dying or there was a
collision, fscache_attach_object() returns without incrementing the cookie
counter - but upon failure of this function, the object is released which
then puts the cookie, whether or not a ref was taken on the cookie.
Fix this by taking a ref on the cookie when it is assigned in
fscache_object_init(), even when we're creating a root object.
Analysis from Kiran Kumar:
This bug has been seen in 4.4.0-124-generic #148-Ubuntu kernel
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1776277
fscache cookie ref count updated incorrectly during fscache object
allocation resulting in following Oops.
kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/internal.h:321!
kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639!
[Cause]
Two threads are trying to do operate on a cookie and two objects.
(1) One thread tries to unmount the filesystem and in process goes over a
huge list of objects marking them dead and deleting the objects.
cookie->usage is also decremented in following path:
nfs_fscache_release_super_cookie
-> __fscache_relinquish_cookie
->__fscache_cookie_put
->BUG_ON(atomic_read(&cookie->usage) <= 0);
(2) A second thread tries to lookup an object for reading data in following
path:
fscache_alloc_object
1) cachefiles_alloc_object
-> fscache_object_init
-> assign cookie, but usage not bumped.
2) fscache_attach_object -> fails in cant_attach_object because the
cookie's backing object or cookie's->parent object are going away
3) fscache_put_object
-> cachefiles_put_object
->fscache_object_destroy
->fscache_cookie_put
->BUG_ON(atomic_read(&cookie->usage) <= 0);
[NOTE from dhowells] It's unclear as to the circumstances in which (2) can
take place, given that thread (1) is in nfs_kill_super(), however a
conflicting NFS mount with slightly different parameters that creates a
different superblock would do it. A backtrace from Kiran seems to show
that this is a possibility:
kernel BUG at/build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639!
...
RIP: __fscache_cookie_put+0x3a/0x40 [fscache]
Call Trace:
__fscache_relinquish_cookie+0x87/0x120 [fscache]
nfs_fscache_release_super_cookie+0x2d/0xb0 [nfs]
nfs_kill_super+0x29/0x40 [nfs]
deactivate_locked_super+0x48/0x80
deactivate_super+0x5c/0x60
cleanup_mnt+0x3f/0x90
__cleanup_mnt+0x12/0x20
task_work_run+0x86/0xb0
exit_to_usermode_loop+0xc2/0xd0
syscall_return_slowpath+0x4e/0x60
int_ret_from_sys_call+0x25/0x9f
[Fix] Bump up the cookie usage in fscache_object_init, when it is first
being assigned a cookie atomically such that the cookie is added and bumped
up if its refcount is not zero. Remove the assignment in
fscache_attach_object().
[Testcase]
I have run ~100 hours of NFS stress tests and not seen this bug recur.
[Regression Potential]
- Limited to fscache/cachefiles.
Fixes: ccc4fc3d11e9 ("FS-Cache: Implement the cookie management part of the netfs API")
Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview. However, it has no ref on that monitor object or on the
associated operation.
What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object. However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.
If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.
Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock. The op can then be enqueued after the lock is
dropped.
The bug can manifest in one of a couple of ways. The first manifestation
looks like:
FS-Cache:
FS-Cache: Assertion failed
FS-Cache: 6 == 5 is false
------------[ cut here ]------------
kernel BUG at fs/fscache/operation.c:494!
RIP: 0010:fscache_put_operation+0x1e3/0x1f0
...
fscache_op_work_func+0x26/0x50
process_one_work+0x131/0x290
worker_thread+0x45/0x360
kthread+0xf8/0x130
? create_worker+0x190/0x190
? kthread_cancel_work_sync+0x10/0x10
ret_from_fork+0x1f/0x30
This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().
The bug can also manifest like the following:
kernel BUG at fs/fscache/operation.c:69!
...
[exception RIP: fscache_enqueue_operation+246]
...
#7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
#8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
#9 [ffff883fff083c48] __wake_up_common at ffffffff810af028
I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Lei Xue <carmark.dlut@gmail.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Reported-by: Anthony DeRobertis <aderobertis@metrics.net>
Reported-by: NeilBrown <neilb@suse.com>
Reported-by: Daniel Axtens <dja@axtens.net>
Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
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Alter the state-check assertion in fscache_enqueue_operation() to allow
cancelled operations to be given processing time so they can be cleaned up.
Also fix a debugging statement that was requiring such operations to have
an object assigned.
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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Before this patch, several functions in rgrp.c checked the value of
rgd->rd_free_clone. That does not take into account blocks that were
reserved by a multi-block reservation. This causes a problem when
space gets tight in the file system. For example, when function
gfs2_inplace_reserve checks to see if a rgrp has enough blocks to
satisfy the request, it can accept a rgrp that it should reject
because, although there are enough blocks to satisfy the request
_now_, those blocks may be reserved for another running process.
A second problem with this occurs when we've reserved the remaining
blocks in an rgrp: function rg_mblk_search() can reject an rgrp
improperly because it calculates:
u32 free_blocks = rgd->rd_free_clone - rgd->rd_reserved;
But rd_reserved includes blocks that the current process just
reserved in its own call to inplace_reserve. For example, it can
reserve the last 128 blocks of an rgrp, then reject that same rgrp
because the above calculates out to free_blocks = 0;
Consequences include, but are not limited to, (1) leaving holes,
and thus increasing file system fragmentation, and (2) reporting
file system is full long before it actually is.
This patch introduces a new function, rgd_free, which returns the
number of clone-free blocks (blocks that are truly free as opposed
to blocks that are still being used because an unlinked file is
still open) minus the number of blocks reserved by processes, but
not counting the blocks we ourselves reserved (because obviously
we need to allocate them).
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Variable 'moved' s being assigned but is never used hence it is
redundant and can be removed. This has been the case ever since commit
c752666c.
Cleans up clang warning:
warning: variable 'moved' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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We only use iomap_readpage for pages that don't have buffer heads
attached yet: iomap_readpage would otherwise read pages from disk that
are marked buffer_uptodate() but not PageUptodate(). Those pages may
actually contain data more recent than what's on disk.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
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Remove the fallback code from direct to buffered I/O for stuffed reads.
For stuffed writes, we must keep the fallback code: the deferred glock
we are holding under direct I/O doesn't allow to write to the inode or
change the file size.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
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Merge xfs branch 'iomap-4.19-merge' into linux-gfs2/for-next. This
brings in readpage and direct I/O support for inline data.
The IOMAP_F_BUFFER_HEAD flag introduced in commit "iomap: add initial
support for writes without buffer heads" needs to be set for gfs2 as
well, so do that in the merge.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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