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Metadata files (e.g. realtime bitmaps and quota files) do not show up in
the bulkstat output, which means that scrub-by-handle does not work;
they can only be checked through a specific scrub type. Therefore, each
scrub type calls xchk_metadata_inode_forks to check the metadata for
whatever's in the file.
Unfortunately, that function doesn't actually check the inode record
itself. Refactor the function a bit to make that happen.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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If the xfs_iget call during setup for the inode scrubber fails with
EINVAL or EFSCORRUPTED, that means that we were unable to create an
incore inode either because the inode btree says the ondisk inode is
free, or because there's corruption in the inode forks.
Either way, we failed to get an incore inode. We'd like to distinguish
between real corruption and the ondisk inode being free, because in the
second case our work is done. To settle this, we try xfs_imap to see if
the ondisk inode is free.
For performance reasons, the setup function doesn't grab its own
reference to the AGI header for the iget lookup, which means that the
setup function can race with another thread that frees the inode, which
is how we end up with iget returning EINVAL.
Unfortunately, the setup function also doesn't take a reference to the
AGI header when it tries the imap, which means that the inode can be
reallocated in the mean time. In this case, the scrub function sees
that there is no incore inode attached to the scrub context and
proclaims that the inode core is corrupt, which is not correct.
Fix this by open-coding xchk_get_inode in the setup function and
modifying it (1) to grab the AGI buffer if the cached inode cannot be
loaded and (2) to retry the iget with our own reference to the AGI.
This avoids all the coherence problems outlined above.
If we grab the AGI buffer, we keep it until the scrub transaction is
torn down. This will be very important for online repair of the ondisk
inode, since it will need exclusive access to the AGI to prevent inode
allocation activity, and the inode cluster buffer.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Right now, there are statements scattered all over the online fsck
codebase about how we can't use XFS_IGET_DONTCACHE because of concerns
about scrub's unusual practice of releasing inodes with transactions
held.
However, iget is the wrong place to handle this -- the DONTCACHE state
doesn't matter at all until we try to *release* the inode, and here we
get things wrong in multiple ways:
First, if we /do/ have a transaction, we must NOT drop the inode,
because the inode could have dirty pages, dropping the inode will
trigger writeback, and writeback can trigger a nested transaction.
Second, if the inode already had an active reference and the DONTCACHE
flag set, the icache hit when scrub grabs another ref will not clear
DONTCACHE. This is sort of by design, since DONTCACHE is now used to
initiate cache drops so that sysadmins can change a file's access mode
between pagecache and DAX.
Third, if we do actually have the last active reference to the inode, we
can set DONTCACHE to avoid polluting the cache. This is the /one/ case
where we actually want that flag.
Create an xchk_irele helper to encode all that logic and switch the
online fsck code to use it. Since this now means that nearly all
scrubbers use the same xfs_iget flags, we can wrap them too.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Gaps in the reference count btree are also significant -- for these
regions, there must not be any overlapping reverse mappings. We don't
currently check this, so make the refcount scrubber more complete.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Teach scrub to flag quota files containing unwritten extents.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Enhance the block map scrubber to check delayed allocation reservations.
Though there are no physical space allocations to check, we do need to
make sure that the range of file offsets being mapped are correct, and
to bump the lastoff cursor so that key order checking works correctly.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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When scrub is checking file fork mappings against rmap records and
the rmap record starts before or ends after the bmap record, check the
adjacent bmap records to make sure that they're adjacent to the one
we're checking. This helps us to detect cases where the rmaps cover
territory that the bmaps do not.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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If the scrub process is sent a fatal signal while we're checking dquots,
the predicate for this will set the error code to -EINTR. Don't then
squash that into -ECANCELED, because the wrong errno turns up in the
trace output.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Teach the summary count checker to count the number of free realtime
extents and compare that to the superblock copy.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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If any part of the per-AG summary counter scan loop aborts without
collecting all of the data we need, the scrubber's observation data will
be invalid. Set the incomplete flag so that we abort the scrub without
reporting false corruptions. Document the data dependency here too.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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When scrub is checking a non-root btree block, it should make sure that
the keys in the parent btree block accurately capture the keyspace that
the child block stores.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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The current directory parent scrubbing code could be tighter in its
execution -- instead of bailing out to userspace after a couple of
seconds of waiting for the (alleged) parent directory's IOLOCK while
refusing to release the child directory's IOLOCK, we could just cycle
both locks until we get both or the child process absorbs a fatal
signal.
Note that because the usual sequence is to take IOLOCKs before grabbing
a transaction, we have to use the _nowait variants on both inodes to
avoid an ABBA deadlock. Since parent pointer checking is the only place
in scrub that needs this kind of functionality, move it to parent.c as a
private function.
Furthermore, if the child directory's parent changes during the lock
cycling, we know that the new parent has stamped the correct parent into
the dotdot entry, so we can conclude that the parent entry is correct.
This eliminates an entire source of -EDEADLOCK-based "retry harder"
scrub executions.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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The current implementation of xfs_btree_has_record returns true if it
finds /any/ record within the given range. Unfortunately, that's not
what the predicate is supposed to do -- it's supposed to test if the
/entire/ range is covered by records.
Therefore, enhance the routine to check that the first record it
encounters starts earlier or at the same point as the low key, the last
record ends at or after the same point as the high key, and that there
aren't any gaps in the records.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Keys for extent interval records in the reverse mapping btree are
supposed to be computed as follows:
(physical block, owner, fork, is_btree, offset)
This provides users the ability to look up a reverse mapping from a file
block mapping record -- start with the physical block; then if there are
multiple records for the same block, move on to the owner; then the
inode fork type; and so on to the file offset.
However, the key comparison functions incorrectly remove the fork/bmbt
information that's encoded in the on-disk offset. This means that
lookup comparisons are only done with:
(physical block, owner, offset)
This means that queries can return incorrect results. On consistent
filesystems this isn't an issue because bmbt blocks and blocks mapped to
an attr fork cannot be shared, but this prevents us from detecting
incorrect fork and bmbt flag bits in the rmap btree.
A previous version of this patch forgot to keep the (un)written state
flag masked during the comparison and caused a major regression in
5.9.x since unwritten extent conversion can update an rmap record
without requiring key updates.
Note that blocks cannot go directly from data fork to attr fork without
being deallocated and reallocated, nor can they be added to or removed
from a bmbt without a free/alloc cycle, so this should not cause any
regressions.
Found by fuzzing keys[1].attrfork = ones on xfs/371.
Fixes: 4b8ed67794fe ("xfs: add rmap btree operations")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Currently, the intent draining code uses a per-AG atomic counter to keep
track of how many writer threads are currently or going to start
processing log intent items for that AG. This isn't particularly
efficient, since every counter update will dirty the cacheline, and the
only code that cares about precise counter values is online scrub, which
shouldn't be running all that often.
Therefore, substitute the atomic_t for a per-cpu counter with a high
batch limit to avoid pingponging cache lines as long as possible. While
updates to per-cpu counters are slower in the single-thread case (on the
author's system, 12ns vs. 8ns), this quickly reverses itself if there
are a lot of CPUs queuing intent items.
Because percpu counter summation is slow, this change shifts most of the
performance impact to code that calls xfs_drain_wait, which means that
online fsck runs a little bit slower to minimize the overhead of regular
runtime code.
To reduce the runtime overhead even further, use a static branch key to
decide if we call wake_up on the drain. For compilers that support jump
labels, the call to wake_up is replaced by a nop sled when nobody is
waiting for intents to drain. For the few compilers that don't, we pay
the cost of reading from a read-mostly atomic counter.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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When a writer thread executes a chain of log intent items, the AG header
buffer locks will cycle during a transaction roll to get from one intent
item to the next in a chain. Although scrub takes all AG header buffer
locks, this isn't sufficient to guard against scrub checking an AG while
that writer thread is in the middle of finishing a chain because there's
no higher level locking primitive guarding allocation groups.
When there's a collision, cross-referencing between data structures
(e.g. rmapbt and refcountbt) yields false corruption events; if repair
is running, this results in incorrect repairs, which is catastrophic.
Fix this by adding to the perag structure the count of active intents
and make scrub wait until it has both AG header buffer locks and the
intent counter reaches zero. This is a little stupid since transactions
can queue intents without taking buffer locks, but it's not the end of
the world for scrub to wait (in KILLABLE state) for those transactions.
In the next patch we'll improve on this facility, but this patch
provides the basic functionality.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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If the program calling online fsck is terminated with a fatal signal,
bail out to userspace by returning EINTR, not EAGAIN. EAGAIN is used by
scrubbers to indicate that we should try again with more resources
locked, and not to indicate that the operation was cancelled. The
miswiring is mostly harmless, but it shows up in the trace data.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Convert all the online scrub code to use the Linux slab allocator
functions directly instead of going through the kmem wrappers.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Memory allocation usage is the same throughout online fsck -- we want
kernel memory, we have to be able to back out if we can't allocate
memory, and we don't want to spray dmesg with memory allocation failure
reports. Standardize the GFP flag usage and document these requirements.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Currently, the only way to lock an allocation group is to hold the AGI
and AGF buffers. If repair needs to roll the transaction while
repairing some AG metadata, it maintains that lock by holding the two
buffers across the transaction roll and joins them afterwards.
However, repair is not the same as the other parts of XFS that employ
this bhold/bjoin sequence, because it's possible that the AGI or AGF
buffers are not actually dirty before the roll. In this case, the
buffer log item can detach from the buffer, which means that we have to
re-set the buffer type in the bli after joining the buffer to the new
transaction so that log recovery will know what to do if the fs fails.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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While scrubbing an allocation group, we don't need to hold the AGFL
buffer as part of the scrub context. All that is necessary to lock an
AG is to hold the AGI and AGF buffers, so fix all the existing users of
the AGFL buffer to grab them only when necessary.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Since the initial introduction of (posix) fallocate back at the turn of
the century, it has been possible to use this syscall to change the
user-visible contents of files. This can happen by extending the file
size during a preallocation, or through any of the newer modes (punch,
zero range). Because the call can be used to change file contents, we
should treat it like we do any other modification to a file -- update
the mtime, and drop set[ug]id privileges/capabilities.
The VFS function file_modified() does all this for us if pass it a
locked inode, so let's make fallocate drop permissions correctly.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Since the initial introduction of (posix) fallocate back at the turn of
the century, it has been possible to use this syscall to change the
user-visible contents of files. This can happen by extending the file
size during a preallocation, or through any of the newer modes (punch,
zero, collapse, insert range). Because the call can be used to change
file contents, we should treat it like we do any other modification to a
file -- update the mtime, and drop set[ug]id privileges/capabilities.
The VFS function file_modified() does all this for us if pass it a
locked inode, so let's make fallocate drop permissions correctly.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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The symbol xfs_name_dotdot is a global variable that the xfs codebase
uses here and there to look up directory dotdot entries. Currently it's
a non-const variable, which means that it's a mutable global variable.
So far nobody's abused this to cause problems, but let's use the
compiler to enforce that.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Various directory functions do not modify their @name parameter,
so mark it const to make that clear. This will enable us to mark
the global xfs_name_dotdot variable as const to prevent mischief.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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XFS does not reserve quota for directory expansion when renaming
children into a directory. This means that we don't reject the
expansion with EDQUOT when we're at or near a hard limit, which means
that unprivileged userspace can use rename() to exceed quota.
Rename operations don't always expand the target directory, and we allow
a rename to proceed with no space reservation if we don't need to add a
block to the target directory to handle the addition. Moreover, the
unlink operation on the source directory generally does not expand the
directory (you'd have to free a block and then cause a btree split) and
it's probably of little consequence to leave the corner case that
renaming a file out of a directory can increase its size.
As with link and unlink, there is a further bug in that we do not
trigger the blockgc workers to try to clear space when we're out of
quota.
Because rename is its own special tricky animal, we'll patch xfs_rename
directly to reserve quota to the rename transaction. We'll leave
cleaning up the rest of xfs_rename for the metadata directory tree
patchset.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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XFS does not reserve quota for directory expansion when linking or
unlinking children from a directory. This means that we don't reject
the expansion with EDQUOT when we're at or near a hard limit, which
means that unprivileged userspace can use link()/unlink() to exceed
quota.
The fix for this is nuanced -- link operations don't always expand the
directory, and we allow a link to proceed with no space reservation if
we don't need to add a block to the directory to handle the addition.
Unlink operations generally do not expand the directory (you'd have to
free a block and then cause a btree split) and we can defer the
directory block freeing if there is no space reservation.
Moreover, there is a further bug in that we do not trigger the blockgc
workers to try to clear space when we're out of quota.
To fix both cases, create a new xfs_trans_alloc_dir function that
allocates the transaction, locks and joins the inodes, and reserves
quota for the directory. If there isn't sufficient space or quota,
we'll switch the caller to reservationless mode. This should prevent
quota usage overruns with the least restriction in functionality.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Combine if tests to reduce the indentation levels of the quota chown
calls in xfs_setattr_nonsize.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
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Filipe Manana pointed out that XFS' behavior w.r.t. setuid/setgid
revocation isn't consistent with btrfs[1] or ext4. Those two
filesystems use the VFS function setattr_copy to convey certain
attributes from struct iattr into the VFS inode structure.
Andrey Zhadchenko reported[2] that XFS uses the wrong user namespace to
decide if it should clear setgid and setuid on a file attribute update.
This is a second symptom of the problem that Filipe noticed.
XFS, on the other hand, open-codes setattr_copy in xfs_setattr_mode,
xfs_setattr_nonsize, and xfs_setattr_time. Regrettably, setattr_copy is
/not/ a simple copy function; it contains additional logic to clear the
setgid bit when setting the mode, and XFS' version no longer matches.
The VFS implements its own setuid/setgid stripping logic, which
establishes consistent behavior. It's a tad unfortunate that it's
scattered across notify_change, should_remove_suid, and setattr_copy but
XFS should really follow the Linux VFS. Adapt XFS to use the VFS
functions and get rid of the old functions.
[1] https://lore.kernel.org/fstests/CAL3q7H47iNQ=Wmk83WcGB-KBJVOEtR9+qGczzCeXJ9Y2KCV25Q@mail.gmail.com/
[2] https://lore.kernel.org/linux-xfs/20220221182218.748084-1-andrey.zhadchenko@virtuozzo.com/
Fixes: 7fa294c8991c ("userns: Allow chown and setgid preservation")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
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There are a few places where we test the current process' capability set
to decide if we're going to be more or less generous with resource
acquisition for a system call. If the process doesn't have the
capability, we can continue the call, albeit in a degraded mode.
These are /not/ the actual security decisions, so it's not proper to use
capable(), which (in certain selinux setups) causes audit messages to
get logged. Switch them to has_capability_noaudit.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
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COW extents are already converted into written real extents after
xfs_reflink_convert_cow_locked(), therefore cmap->br_state should
reflect it.
Otherwise, there is another necessary unwritten convertion
triggered in xfs_dio_write_end_io() for direct I/O cases.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge misc fixes from David Howells:
"A set of patches for watch_queue filter issues noted by Jann. I've
added in a cleanup patch from Christophe Jaillet to convert to using
formal bitmap specifiers for the note allocation bitmap.
Also two filesystem fixes (afs and cachefiles)"
* emailed patches from David Howells <dhowells@redhat.com>:
cachefiles: Fix volume coherency attribute
afs: Fix potential thrashing in afs writeback
watch_queue: Make comment about setting ->defunct more accurate
watch_queue: Fix lack of barrier/sync/lock between post and read
watch_queue: Free the alloc bitmap when the watch_queue is torn down
watch_queue: Fix the alloc bitmap size to reflect notes allocated
watch_queue: Use the bitmap API when applicable
watch_queue: Fix to always request a pow-of-2 pipe ring size
watch_queue: Fix to release page in ->release()
watch_queue, pipe: Free watchqueue state after clearing pipe ring
watch_queue: Fix filter limit check
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A network filesystem may set coherency data on a volume cookie, and if
given, cachefiles will store this in an xattr on the directory in the
cache corresponding to the volume.
The function that sets the xattr just stores the contents of the volume
coherency buffer directly into the xattr, with nothing added; the
checking function, on the other hand, has a cut'n'paste error whereby it
tries to interpret the xattr contents as would be the xattr on an
ordinary file (using the cachefiles_xattr struct). This results in a
failure to match the coherency data because the buffer ends up being
shifted by 18 bytes.
Fix this by defining a structure specifically for the volume xattr and
making both the setting and checking functions use it.
Since the volume coherency doesn't work if used, take the opportunity to
insert a reserved field for future use, set it to 0 and check that it is
0. Log mismatch through the appropriate tracepoint.
Note that this only affects cifs; 9p, afs, ceph and nfs don't use the
volume coherency data at the moment.
Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data")
Reported-by: Rohith Surabattula <rohiths.msft@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Steve French <smfrench@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In afs_writepages_region(), if the dirty page we find is undergoing
writeback or write to cache, but the sync_mode is WB_SYNC_NONE, we go
round the loop trying the same page again and again with no pausing or
waiting unless and until another thread manages to clear the writeback
and fscache flags.
Fix this with three measures:
(1) Advance start to after the page we found.
(2) Break out of the loop and return if rescheduling is requested.
(3) Arbitrarily give up after a maximum of 5 skips.
Fixes: 31143d5d515e ("AFS: implement basic file write support")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Acked-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://lore.kernel.org/r/164692725757.2097000.2060513769492301854.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There's nothing to synchronise post_one_notification() versus
pipe_read(). Whilst posting is done under pipe->rd_wait.lock, the
reader only takes pipe->mutex which cannot bar notification posting as
that may need to be made from contexts that cannot sleep.
Fix this by setting pipe->head with a barrier in post_one_notification()
and reading pipe->head with a barrier in pipe_read().
If that's not sufficient, the rd_wait.lock will need to be taken,
possibly in a ->confirm() op so that it only applies to notifications.
The lock would, however, have to be dropped before copy_page_to_iter()
is invoked.
Fixes: c73be61cede5 ("pipe: Add general notification queue support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In free_pipe_info(), free the watchqueue state after clearing the pipe
ring as each pipe ring descriptor has a release function, and in the
case of a notification message, this is watch_queue_pipe_buf_release()
which tries to mark the allocation bitmap that was previously released.
Fix this by moving the put of the pipe's ref on the watch queue to after
the ring has been cleared. We still need to call watch_queue_clear()
before doing that to make sure that the pipe is disconnected from any
notification sources first.
Fixes: c73be61cede5 ("pipe: Add general notification queue support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse fixes from Miklos Szeredi:
- Fix an issue with splice on the fuse device
- Fix a regression in the fileattr API conversion
- Add a small userspace API improvement
* tag 'fuse-fixes-5.17-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: fix pipe buffer lifetime for direct_io
fuse: move FUSE_SUPER_MAGIC definition to magic.h
fuse: fix fileattr op failure
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In FOPEN_DIRECT_IO mode, fuse_file_write_iter() calls
fuse_direct_write_iter(), which normally calls fuse_direct_io(), which then
imports the write buffer with fuse_get_user_pages(), which uses
iov_iter_get_pages() to grab references to userspace pages instead of
actually copying memory.
On the filesystem device side, these pages can then either be read to
userspace (via fuse_dev_read()), or splice()d over into a pipe using
fuse_dev_splice_read() as pipe buffers with &nosteal_pipe_buf_ops.
This is wrong because after fuse_dev_do_read() unlocks the FUSE request,
the userspace filesystem can mark the request as completed, causing write()
to return. At that point, the userspace filesystem should no longer have
access to the pipe buffer.
Fix by copying pages coming from the user address space to new pipe
buffers.
Reported-by: Jann Horn <jannh@google.com>
Fixes: c3021629a0d8 ("fuse: support splice() reading from fuse device")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more fixes for various problems that have user visible effects
or seem to be urgent:
- fix corruption when combining DIO and non-blocking io_uring over
multiple extents (seen on MariaDB)
- fix relocation crash due to premature return from commit
- fix quota deadlock between rescan and qgroup removal
- fix item data bounds checks in tree-checker (found on a fuzzed
image)
- fix fsync of prealloc extents after EOF
- add missing run of delayed items after unlink during log replay
- don't start relocation until snapshot drop is finished
- fix reversed condition for subpage writers locking
- fix warning on page error"
* tag 'for-5.17-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fallback to blocking mode when doing async dio over multiple extents
btrfs: add missing run of delayed items after unlink during log replay
btrfs: qgroup: fix deadlock between rescan worker and remove qgroup
btrfs: fix relocation crash due to premature return from btrfs_commit_transaction()
btrfs: do not start relocation until in progress drops are done
btrfs: tree-checker: use u64 for item data end to avoid overflow
btrfs: do not WARN_ON() if we have PageError set
btrfs: fix lost prealloc extents beyond eof after full fsync
btrfs: subpage: fix a wrong check on subpage->writers
|
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Since bit 57 was exported for uffd-wp write-protected (commit
fb8e37f35a2f: "mm/pagemap: export uffd-wp protection information"),
fixing it can reduce some unnecessary confusion.
Link: https://lkml.kernel.org/r/20220301044538.3042713-1-yun.zhou@windriver.com
Fixes: fb8e37f35a2fe1 ("mm/pagemap: export uffd-wp protection information")
Signed-off-by: Yun Zhou <yun.zhou@windriver.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Tiberiu A Georgescu <tiberiu.georgescu@nutanix.com>
Cc: Florian Schmidt <florian.schmidt@nutanix.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Colin Cross <ccross@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible. This simplifies the code
and allows easier sharing of anon_vma_name structures when they
represent the same name.
[surenb@google.com: fix comment]
Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Colin Cross <ccross@google.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Some users recently reported that MariaDB was getting a read corruption
when using io_uring on top of btrfs. This started to happen in 5.16,
after commit 51bd9563b6783d ("btrfs: fix deadlock due to page faults
during direct IO reads and writes"). That changed btrfs to use the new
iomap flag IOMAP_DIO_PARTIAL and to disable page faults before calling
iomap_dio_rw(). This was necessary to fix deadlocks when the iovector
corresponds to a memory mapped file region. That type of scenario is
exercised by test case generic/647 from fstests.
For this MariaDB scenario, we attempt to read 16K from file offset X
using IOCB_NOWAIT and io_uring. In that range we have 4 extents, each
with a size of 4K, and what happens is the following:
1) btrfs_direct_read() disables page faults and calls iomap_dio_rw();
2) iomap creates a struct iomap_dio object, its reference count is
initialized to 1 and its ->size field is initialized to 0;
3) iomap calls btrfs_dio_iomap_begin() with file offset X, which finds
the first 4K extent, and setups an iomap for this extent consisting
of a single page;
4) At iomap_dio_bio_iter(), we are able to access the first page of the
buffer (struct iov_iter) with bio_iov_iter_get_pages() without
triggering a page fault;
5) iomap submits a bio for this 4K extent
(iomap_dio_submit_bio() -> btrfs_submit_direct()) and increments
the refcount on the struct iomap_dio object to 2; The ->size field
of the struct iomap_dio object is incremented to 4K;
6) iomap calls btrfs_iomap_begin() again, this time with a file
offset of X + 4K. There we setup an iomap for the next extent
that also has a size of 4K;
7) Then at iomap_dio_bio_iter() we call bio_iov_iter_get_pages(),
which tries to access the next page (2nd page) of the buffer.
This triggers a page fault and returns -EFAULT;
8) At __iomap_dio_rw() we see the -EFAULT, but we reset the error
to 0 because we passed the flag IOMAP_DIO_PARTIAL to iomap and
the struct iomap_dio object has a ->size value of 4K (we submitted
a bio for an extent already). The 'wait_for_completion' variable
is not set to true, because our iocb has IOCB_NOWAIT set;
9) At the bottom of __iomap_dio_rw(), we decrement the reference count
of the struct iomap_dio object from 2 to 1. Because we were not
the only ones holding a reference on it and 'wait_for_completion' is
set to false, -EIOCBQUEUED is returned to btrfs_direct_read(), which
just returns it up the callchain, up to io_uring;
10) The bio submitted for the first extent (step 5) completes and its
bio endio function, iomap_dio_bio_end_io(), decrements the last
reference on the struct iomap_dio object, resulting in calling
iomap_dio_complete_work() -> iomap_dio_complete().
11) At iomap_dio_complete() we adjust the iocb->ki_pos from X to X + 4K
and return 4K (the amount of io done) to iomap_dio_complete_work();
12) iomap_dio_complete_work() calls the iocb completion callback,
iocb->ki_complete() with a second argument value of 4K (total io
done) and the iocb with the adjust ki_pos of X + 4K. This results
in completing the read request for io_uring, leaving it with a
result of 4K bytes read, and only the first page of the buffer
filled in, while the remaining 3 pages, corresponding to the other
3 extents, were not filled;
13) For the application, the result is unexpected because if we ask
to read N bytes, it expects to get N bytes read as long as those
N bytes don't cross the EOF (i_size).
MariaDB reports this as an error, as it's not expecting a short read,
since it knows it's asking for read operations fully within the i_size
boundary. This is typical in many applications, but it may also be
questionable if they should react to such short reads by issuing more
read calls to get the remaining data. Nevertheless, the short read
happened due to a change in btrfs regarding how it deals with page
faults while in the middle of a read operation, and there's no reason
why btrfs can't have the previous behaviour of returning the whole data
that was requested by the application.
The problem can also be triggered with the following simple program:
/* Get O_DIRECT */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <liburing.h>
int main(int argc, char *argv[])
{
char *foo_path;
struct io_uring ring;
struct io_uring_sqe *sqe;
struct io_uring_cqe *cqe;
struct iovec iovec;
int fd;
long pagesize;
void *write_buf;
void *read_buf;
ssize_t ret;
int i;
if (argc != 2) {
fprintf(stderr, "Use: %s <directory>\n", argv[0]);
return 1;
}
foo_path = malloc(strlen(argv[1]) + 5);
if (!foo_path) {
fprintf(stderr, "Failed to allocate memory for file path\n");
return 1;
}
strcpy(foo_path, argv[1]);
strcat(foo_path, "/foo");
/*
* Create file foo with 2 extents, each with a size matching
* the page size. Then allocate a buffer to read both extents
* with io_uring, using O_DIRECT and IOCB_NOWAIT. Before doing
* the read with io_uring, access the first page of the buffer
* to fault it in, so that during the read we only trigger a
* page fault when accessing the second page of the buffer.
*/
fd = open(foo_path, O_CREAT | O_TRUNC | O_WRONLY |
O_DIRECT, 0666);
if (fd == -1) {
fprintf(stderr,
"Failed to create file 'foo': %s (errno %d)",
strerror(errno), errno);
return 1;
}
pagesize = sysconf(_SC_PAGE_SIZE);
ret = posix_memalign(&write_buf, pagesize, 2 * pagesize);
if (ret) {
fprintf(stderr, "Failed to allocate write buffer\n");
return 1;
}
memset(write_buf, 0xab, pagesize);
memset(write_buf + pagesize, 0xcd, pagesize);
/* Create 2 extents, each with a size matching page size. */
for (i = 0; i < 2; i++) {
ret = pwrite(fd, write_buf + i * pagesize, pagesize,
i * pagesize);
if (ret != pagesize) {
fprintf(stderr,
"Failed to write to file, ret = %ld errno %d (%s)\n",
ret, errno, strerror(errno));
return 1;
}
ret = fsync(fd);
if (ret != 0) {
fprintf(stderr, "Failed to fsync file\n");
return 1;
}
}
close(fd);
fd = open(foo_path, O_RDONLY | O_DIRECT);
if (fd == -1) {
fprintf(stderr,
"Failed to open file 'foo': %s (errno %d)",
strerror(errno), errno);
return 1;
}
ret = posix_memalign(&read_buf, pagesize, 2 * pagesize);
if (ret) {
fprintf(stderr, "Failed to allocate read buffer\n");
return 1;
}
/*
* Fault in only the first page of the read buffer.
* We want to trigger a page fault for the 2nd page of the
* read buffer during the read operation with io_uring
* (O_DIRECT and IOCB_NOWAIT).
*/
memset(read_buf, 0, 1);
ret = io_uring_queue_init(1, &ring, 0);
if (ret != 0) {
fprintf(stderr, "Failed to create io_uring queue\n");
return 1;
}
sqe = io_uring_get_sqe(&ring);
if (!sqe) {
fprintf(stderr, "Failed to get io_uring sqe\n");
return 1;
}
iovec.iov_base = read_buf;
iovec.iov_len = 2 * pagesize;
io_uring_prep_readv(sqe, fd, &iovec, 1, 0);
ret = io_uring_submit_and_wait(&ring, 1);
if (ret != 1) {
fprintf(stderr,
"Failed at io_uring_submit_and_wait()\n");
return 1;
}
ret = io_uring_wait_cqe(&ring, &cqe);
if (ret < 0) {
fprintf(stderr, "Failed at io_uring_wait_cqe()\n");
return 1;
}
printf("io_uring read result for file foo:\n\n");
printf(" cqe->res == %d (expected %d)\n", cqe->res, 2 * pagesize);
printf(" memcmp(read_buf, write_buf) == %d (expected 0)\n",
memcmp(read_buf, write_buf, 2 * pagesize));
io_uring_cqe_seen(&ring, cqe);
io_uring_queue_exit(&ring);
return 0;
}
When running it on an unpatched kernel:
$ gcc io_uring_test.c -luring
$ mkfs.btrfs -f /dev/sda
$ mount /dev/sda /mnt/sda
$ ./a.out /mnt/sda
io_uring read result for file foo:
cqe->res == 4096 (expected 8192)
memcmp(read_buf, write_buf) == -205 (expected 0)
After this patch, the read always returns 8192 bytes, with the buffer
filled with the correct data. Although that reproducer always triggers
the bug in my test vms, it's possible that it will not be so reliable
on other environments, as that can happen if the bio for the first
extent completes and decrements the reference on the struct iomap_dio
object before we do the atomic_dec_and_test() on the reference at
__iomap_dio_rw().
Fix this in btrfs by having btrfs_dio_iomap_begin() return -EAGAIN
whenever we try to satisfy a non blocking IO request (IOMAP_NOWAIT flag
set) over a range that spans multiple extents (or a mix of extents and
holes). This avoids returning success to the caller when we only did
partial IO, which is not optimal for writes and for reads it's actually
incorrect, as the caller doesn't expect to get less bytes read than it has
requested (unless EOF is crossed), as previously mentioned. This is also
the type of behaviour that xfs follows (xfs_direct_write_iomap_begin()),
even though it doesn't use IOMAP_DIO_PARTIAL.
A test case for fstests will follow soon.
Link: https://lore.kernel.org/linux-btrfs/CABVffEM0eEWho+206m470rtM0d9J8ue85TtR-A_oVTuGLWFicA@mail.gmail.com/
Link: https://lore.kernel.org/linux-btrfs/CAHF2GV6U32gmqSjLe=XKgfcZAmLCiH26cJ2OnHGp5x=VAH4OHQ@mail.gmail.com/
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
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When cachefiles_shorten_object() calls fallocate() to shape the cache
file to match the DIO size, it passes the total file size it wants to
achieve, not the amount of zeros that should be inserted. Since this is
meant to preallocate that amount of storage for the file, it can cause
the cache to fill up the disk and hit ENOSPC.
Fix this by passing the length actually required to go from the current
EOF to the desired EOF.
Fixes: 7623ed6772de ("cachefiles: Implement cookie resize for truncate")
Reported-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164630854858.3665356.17419701804248490708.stgit@warthog.procyon.org.uk # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs fix from Gao Xiang:
"A one-line patch to fix the new ztailpacking feature on > 4GiB
filesystems because z_idataoff can get trimmed improperly.
ztailpacking is still a brand new EXPERIMENTAL feature, but it'd be
better to fix the issue as soon as possible to avoid unnecessary
backporting.
Summary:
- Fix ztailpacking z_idataoff getting trimmed on > 4GiB filesystems"
* tag 'erofs-for-5.17-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: fix ztailpacking on > 4GiB filesystems
|
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During log replay, whenever we need to check if a name (dentry) exists in
a directory we do searches on the subvolume tree for inode references or
or directory entries (BTRFS_DIR_INDEX_KEY keys, and BTRFS_DIR_ITEM_KEY
keys as well, before kernel 5.17). However when during log replay we
unlink a name, through btrfs_unlink_inode(), we may not delete inode
references and dir index keys from a subvolume tree and instead just add
the deletions to the delayed inode's delayed items, which will only be
run when we commit the transaction used for log replay. This means that
after an unlink operation during log replay, if we attempt to search for
the same name during log replay, we will not see that the name was already
deleted, since the deletion is recorded only on the delayed items.
We run delayed items after every unlink operation during log replay,
except at unlink_old_inode_refs() and at add_inode_ref(). This was due
to an overlook, as delayed items should be run after evert unlink, for
the reasons stated above.
So fix those two cases.
Fixes: 0d836392cadd5 ("Btrfs: fix mount failure after fsync due to hard link recreation")
Fixes: 1f250e929a9c9 ("Btrfs: fix log replay failure after unlink and link combination")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The commit e804861bd4e6 ("btrfs: fix deadlock between quota disable and
qgroup rescan worker") by Kawasaki resolves deadlock between quota
disable and qgroup rescan worker. But also there is a deadlock case like
it. It's about enabling or disabling quota and creating or removing
qgroup. It can be reproduced in simple script below.
for i in {1..100}
do
btrfs quota enable /mnt &
btrfs qgroup create 1/0 /mnt &
btrfs qgroup destroy 1/0 /mnt &
btrfs quota disable /mnt &
done
Here's why the deadlock happens:
1) The quota rescan task is running.
2) Task A calls btrfs_quota_disable(), locks the qgroup_ioctl_lock
mutex, and then calls btrfs_qgroup_wait_for_completion(), to wait for
the quota rescan task to complete.
3) Task B calls btrfs_remove_qgroup() and it blocks when trying to lock
the qgroup_ioctl_lock mutex, because it's being held by task A. At that
point task B is holding a transaction handle for the current transaction.
4) The quota rescan task calls btrfs_commit_transaction(). This results
in it waiting for all other tasks to release their handles on the
transaction, but task B is blocked on the qgroup_ioctl_lock mutex
while holding a handle on the transaction, and that mutex is being held
by task A, which is waiting for the quota rescan task to complete,
resulting in a deadlock between these 3 tasks.
To resolve this issue, the thread disabling quota should unlock
qgroup_ioctl_lock before waiting rescan completion. Move
btrfs_qgroup_wait_for_completion() after unlock of qgroup_ioctl_lock.
Fixes: e804861bd4e6 ("btrfs: fix deadlock between quota disable and qgroup rescan worker")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Sidong Yang <realwakka@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
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btrfs_commit_transaction()
We are seeing crashes similar to the following trace:
[38.969182] WARNING: CPU: 20 PID: 2105 at fs/btrfs/relocation.c:4070 btrfs_relocate_block_group+0x2dc/0x340 [btrfs]
[38.973556] CPU: 20 PID: 2105 Comm: btrfs Not tainted 5.17.0-rc4 #54
[38.974580] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[38.976539] RIP: 0010:btrfs_relocate_block_group+0x2dc/0x340 [btrfs]
[38.980336] RSP: 0000:ffffb0dd42e03c20 EFLAGS: 00010206
[38.981218] RAX: ffff96cfc4ede800 RBX: ffff96cfc3ce0000 RCX: 000000000002ca14
[38.982560] RDX: 0000000000000000 RSI: 4cfd109a0bcb5d7f RDI: ffff96cfc3ce0360
[38.983619] RBP: ffff96cfc309c000 R08: 0000000000000000 R09: 0000000000000000
[38.984678] R10: ffff96cec0000001 R11: ffffe84c80000000 R12: ffff96cfc4ede800
[38.985735] R13: 0000000000000000 R14: 0000000000000000 R15: ffff96cfc3ce0360
[38.987146] FS: 00007f11c15218c0(0000) GS:ffff96d6dfb00000(0000) knlGS:0000000000000000
[38.988662] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[38.989398] CR2: 00007ffc922c8e60 CR3: 00000001147a6001 CR4: 0000000000370ee0
[38.990279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[38.991219] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[38.992528] Call Trace:
[38.992854] <TASK>
[38.993148] btrfs_relocate_chunk+0x27/0xe0 [btrfs]
[38.993941] btrfs_balance+0x78e/0xea0 [btrfs]
[38.994801] ? vsnprintf+0x33c/0x520
[38.995368] ? __kmalloc_track_caller+0x351/0x440
[38.996198] btrfs_ioctl_balance+0x2b9/0x3a0 [btrfs]
[38.997084] btrfs_ioctl+0x11b0/0x2da0 [btrfs]
[38.997867] ? mod_objcg_state+0xee/0x340
[38.998552] ? seq_release+0x24/0x30
[38.999184] ? proc_nr_files+0x30/0x30
[38.999654] ? call_rcu+0xc8/0x2f0
[39.000228] ? __x64_sys_ioctl+0x84/0xc0
[39.000872] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[39.001973] __x64_sys_ioctl+0x84/0xc0
[39.002566] do_syscall_64+0x3a/0x80
[39.003011] entry_SYSCALL_64_after_hwframe+0x44/0xae
[39.003735] RIP: 0033:0x7f11c166959b
[39.007324] RSP: 002b:00007fff2543e998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[39.008521] RAX: ffffffffffffffda RBX: 00007f11c1521698 RCX: 00007f11c166959b
[39.009833] RDX: 00007fff2543ea40 RSI: 00000000c4009420 RDI: 0000000000000003
[39.011270] RBP: 0000000000000003 R08: 0000000000000013 R09: 00007f11c16f94e0
[39.012581] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff25440df3
[39.014046] R13: 0000000000000000 R14: 00007fff2543ea40 R15: 0000000000000001
[39.015040] </TASK>
[39.015418] ---[ end trace 0000000000000000 ]---
[43.131559] ------------[ cut here ]------------
[43.132234] kernel BUG at fs/btrfs/extent-tree.c:2717!
[43.133031] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[43.133702] CPU: 1 PID: 1839 Comm: btrfs Tainted: G W 5.17.0-rc4 #54
[43.134863] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[43.136426] RIP: 0010:unpin_extent_range+0x37a/0x4f0 [btrfs]
[43.139913] RSP: 0000:ffffb0dd4216bc70 EFLAGS: 00010246
[43.140629] RAX: 0000000000000000 RBX: ffff96cfc34490f8 RCX: 0000000000000001
[43.141604] RDX: 0000000080000001 RSI: 0000000051d00000 RDI: 00000000ffffffff
[43.142645] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff96cfd07dca50
[43.143669] R10: ffff96cfc46e8a00 R11: fffffffffffec000 R12: 0000000041d00000
[43.144657] R13: ffff96cfc3ce0000 R14: ffffb0dd4216bd08 R15: 0000000000000000
[43.145686] FS: 00007f7657dd68c0(0000) GS:ffff96d6df640000(0000) knlGS:0000000000000000
[43.146808] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[43.147584] CR2: 00007f7fe81bf5b0 CR3: 00000001093ee004 CR4: 0000000000370ee0
[43.148589] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[43.149581] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[43.150559] Call Trace:
[43.150904] <TASK>
[43.151253] btrfs_finish_extent_commit+0x88/0x290 [btrfs]
[43.152127] btrfs_commit_transaction+0x74f/0xaa0 [btrfs]
[43.152932] ? btrfs_attach_transaction_barrier+0x1e/0x50 [btrfs]
[43.153786] btrfs_ioctl+0x1edc/0x2da0 [btrfs]
[43.154475] ? __check_object_size+0x150/0x170
[43.155170] ? preempt_count_add+0x49/0xa0
[43.155753] ? __x64_sys_ioctl+0x84/0xc0
[43.156437] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[43.157456] __x64_sys_ioctl+0x84/0xc0
[43.157980] do_syscall_64+0x3a/0x80
[43.158543] entry_SYSCALL_64_after_hwframe+0x44/0xae
[43.159231] RIP: 0033:0x7f7657f1e59b
[43.161819] RSP: 002b:00007ffda5cd1658 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[43.162702] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f7657f1e59b
[43.163526] RDX: 0000000000000000 RSI: 0000000000009408 RDI: 0000000000000003
[43.164358] RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
[43.165208] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[43.166029] R13: 00005621b91c3232 R14: 00005621b91ba580 R15: 00007ffda5cd1800
[43.166863] </TASK>
[43.167125] Modules linked in: btrfs blake2b_generic xor pata_acpi ata_piix libata raid6_pq scsi_mod libcrc32c virtio_net virtio_rng net_failover rng_core failover scsi_common
[43.169552] ---[ end trace 0000000000000000 ]---
[43.171226] RIP: 0010:unpin_extent_range+0x37a/0x4f0 [btrfs]
[43.174767] RSP: 0000:ffffb0dd4216bc70 EFLAGS: 00010246
[43.175600] RAX: 0000000000000000 RBX: ffff96cfc34490f8 RCX: 0000000000000001
[43.176468] RDX: 0000000080000001 RSI: 0000000051d00000 RDI: 00000000ffffffff
[43.177357] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff96cfd07dca50
[43.178271] R10: ffff96cfc46e8a00 R11: fffffffffffec000 R12: 0000000041d00000
[43.179178] R13: ffff96cfc3ce0000 R14: ffffb0dd4216bd08 R15: 0000000000000000
[43.180071] FS: 00007f7657dd68c0(0000) GS:ffff96d6df800000(0000) knlGS:0000000000000000
[43.181073] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[43.181808] CR2: 00007fe09905f010 CR3: 00000001093ee004 CR4: 0000000000370ee0
[43.182706] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[43.183591] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
We first hit the WARN_ON(rc->block_group->pinned > 0) in
btrfs_relocate_block_group() and then the BUG_ON(!cache) in
unpin_extent_range(). This tells us that we are exiting relocation and
removing the block group with bytes still pinned for that block group.
This is supposed to be impossible: the last thing relocate_block_group()
does is commit the transaction to get rid of pinned extents.
Commit d0c2f4fa555e ("btrfs: make concurrent fsyncs wait less when
waiting for a transaction commit") introduced an optimization so that
commits from fsync don't have to wait for the previous commit to unpin
extents. This was only intended to affect fsync, but it inadvertently
made it possible for any commit to skip waiting for the previous commit
to unpin. This is because if a call to btrfs_commit_transaction() finds
that another thread is already committing the transaction, it waits for
the other thread to complete the commit and then returns. If that other
thread was in fsync, then it completes the commit without completing the
previous commit. This makes the following sequence of events possible:
Thread 1____________________|Thread 2 (fsync)_____________________|Thread 3 (balance)___________________
btrfs_commit_transaction(N) | |
btrfs_run_delayed_refs | |
pin extents | |
... | |
state = UNBLOCKED |btrfs_sync_file |
| btrfs_start_transaction(N + 1) |relocate_block_group
| | btrfs_join_transaction(N + 1)
| btrfs_commit_transaction(N + 1) |
... | trans->state = COMMIT_START |
| | btrfs_commit_transaction(N + 1)
| | wait_for_commit(N + 1, COMPLETED)
| wait_for_commit(N, SUPER_COMMITTED)|
state = SUPER_COMMITTED | ... |
btrfs_finish_extent_commit| |
unpin_extent_range() | trans->state = COMPLETED |
| | return
| |
... | |Thread 1 isn't done, so pinned > 0
| |and we WARN
| |
| |btrfs_remove_block_group
unpin_extent_range() | |
Thread 3 removed the | |
block group, so we BUG| |
There are other sequences involving SUPER_COMMITTED transactions that
can cause a similar outcome.
We could fix this by making relocation explicitly wait for unpinning,
but there may be other cases that need it. Josef mentioned ENOSPC
flushing and the free space cache inode as other potential victims.
Rather than playing whack-a-mole, this fix is conservative and makes all
commits not in fsync wait for all previous transactions, which is what
the optimization intended.
Fixes: d0c2f4fa555e ("btrfs: make concurrent fsyncs wait less when waiting for a transaction commit")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
We hit a bug with a recovering relocation on mount for one of our file
systems in production. I reproduced this locally by injecting errors
into snapshot delete with balance running at the same time. This
presented as an error while looking up an extent item
WARNING: CPU: 5 PID: 1501 at fs/btrfs/extent-tree.c:866 lookup_inline_extent_backref+0x647/0x680
CPU: 5 PID: 1501 Comm: btrfs-balance Not tainted 5.16.0-rc8+ #8
RIP: 0010:lookup_inline_extent_backref+0x647/0x680
RSP: 0018:ffffae0a023ab960 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000000
RBP: ffff943fd2a39b60 R08: 0000000000000000 R09: 0000000000000001
R10: 0001434088152de0 R11: 0000000000000000 R12: 0000000001d05000
R13: ffff943fd2a39b60 R14: ffff943fdb96f2a0 R15: ffff9442fc923000
FS: 0000000000000000(0000) GS:ffff944e9eb40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1157b1fca8 CR3: 000000010f092000 CR4: 0000000000350ee0
Call Trace:
<TASK>
insert_inline_extent_backref+0x46/0xd0
__btrfs_inc_extent_ref.isra.0+0x5f/0x200
? btrfs_merge_delayed_refs+0x164/0x190
__btrfs_run_delayed_refs+0x561/0xfa0
? btrfs_search_slot+0x7b4/0xb30
? btrfs_update_root+0x1a9/0x2c0
btrfs_run_delayed_refs+0x73/0x1f0
? btrfs_update_root+0x1a9/0x2c0
btrfs_commit_transaction+0x50/0xa50
? btrfs_update_reloc_root+0x122/0x220
prepare_to_merge+0x29f/0x320
relocate_block_group+0x2b8/0x550
btrfs_relocate_block_group+0x1a6/0x350
btrfs_relocate_chunk+0x27/0xe0
btrfs_balance+0x777/0xe60
balance_kthread+0x35/0x50
? btrfs_balance+0xe60/0xe60
kthread+0x16b/0x190
? set_kthread_struct+0x40/0x40
ret_from_fork+0x22/0x30
</TASK>
Normally snapshot deletion and relocation are excluded from running at
the same time by the fs_info->cleaner_mutex. However if we had a
pending balance waiting to get the ->cleaner_mutex, and a snapshot
deletion was running, and then the box crashed, we would come up in a
state where we have a half deleted snapshot.
Again, in the normal case the snapshot deletion needs to complete before
relocation can start, but in this case relocation could very well start
before the snapshot deletion completes, as we simply add the root to the
dead roots list and wait for the next time the cleaner runs to clean up
the snapshot.
Fix this by setting a bit on the fs_info if we have any DEAD_ROOT's that
had a pending drop_progress key. If they do then we know we were in the
middle of the drop operation and set a flag on the fs_info. Then
balance can wait until this flag is cleared to start up again.
If there are DEAD_ROOT's that don't have a drop_progress set then we're
safe to start balance right away as we'll be properly protected by the
cleaner_mutex.
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
User reported there is an array-index-out-of-bounds access while
mounting the crafted image:
[350.411942 ] loop0: detected capacity change from 0 to 262144
[350.427058 ] BTRFS: device fsid a62e00e8-e94e-4200-8217-12444de93c2e devid 1 transid 8 /dev/loop0 scanned by systemd-udevd (1044)
[350.428564 ] BTRFS info (device loop0): disk space caching is enabled
[350.428568 ] BTRFS info (device loop0): has skinny extents
[350.429589 ]
[350.429619 ] UBSAN: array-index-out-of-bounds in fs/btrfs/struct-funcs.c:161:1
[350.429636 ] index 1048096 is out of range for type 'page *[16]'
[350.429650 ] CPU: 0 PID: 9 Comm: kworker/u8:1 Not tainted 5.16.0-rc4
[350.429652 ] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[350.429653 ] Workqueue: btrfs-endio-meta btrfs_work_helper [btrfs]
[350.429772 ] Call Trace:
[350.429774 ] <TASK>
[350.429776 ] dump_stack_lvl+0x47/0x5c
[350.429780 ] ubsan_epilogue+0x5/0x50
[350.429786 ] __ubsan_handle_out_of_bounds+0x66/0x70
[350.429791 ] btrfs_get_16+0xfd/0x120 [btrfs]
[350.429832 ] check_leaf+0x754/0x1a40 [btrfs]
[350.429874 ] ? filemap_read+0x34a/0x390
[350.429878 ] ? load_balance+0x175/0xfc0
[350.429881 ] validate_extent_buffer+0x244/0x310 [btrfs]
[350.429911 ] btrfs_validate_metadata_buffer+0xf8/0x100 [btrfs]
[350.429935 ] end_bio_extent_readpage+0x3af/0x850 [btrfs]
[350.429969 ] ? newidle_balance+0x259/0x480
[350.429972 ] end_workqueue_fn+0x29/0x40 [btrfs]
[350.429995 ] btrfs_work_helper+0x71/0x330 [btrfs]
[350.430030 ] ? __schedule+0x2fb/0xa40
[350.430033 ] process_one_work+0x1f6/0x400
[350.430035 ] ? process_one_work+0x400/0x400
[350.430036 ] worker_thread+0x2d/0x3d0
[350.430037 ] ? process_one_work+0x400/0x400
[350.430038 ] kthread+0x165/0x190
[350.430041 ] ? set_kthread_struct+0x40/0x40
[350.430043 ] ret_from_fork+0x1f/0x30
[350.430047 ] </TASK>
[350.430047 ]
[350.430077 ] BTRFS warning (device loop0): bad eb member start: ptr 0xffe20f4e start 20975616 member offset 4293005178 size 2
btrfs check reports:
corrupt leaf: root=3 block=20975616 physical=20975616 slot=1, unexpected
item end, have 4294971193 expect 3897
The first slot item offset is 4293005033 and the size is 1966160.
In check_leaf, we use btrfs_item_end() to check item boundary versus
extent_buffer data size. However, return type of btrfs_item_end() is u32.
(u32)(4293005033 + 1966160) == 3897, overflow happens and the result 3897
equals to leaf data size reasonably.
Fix it by use u64 variable to store item data end in check_leaf() to
avoid u32 overflow.
This commit does solve the invalid memory access showed by the stack
trace. However, its metadata profile is DUP and another copy of the
leaf is fine. So the image can be mounted successfully. But when umount
is called, the ASSERT btrfs_mark_buffer_dirty() will be triggered
because the only node in extent tree has 0 item and invalid owner. It's
solved by another commit
"btrfs: check extent buffer owner against the owner rootid".
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215299
Reported-by: Wenqing Liu <wenqingliu0120@gmail.com>
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Whenever we do any extent buffer operations we call
assert_eb_page_uptodate() to complain loudly if we're operating on an
non-uptodate page. Our overnight tests caught this warning earlier this
week
WARNING: CPU: 1 PID: 553508 at fs/btrfs/extent_io.c:6849 assert_eb_page_uptodate+0x3f/0x50
CPU: 1 PID: 553508 Comm: kworker/u4:13 Tainted: G W 5.17.0-rc3+ #564
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Workqueue: btrfs-cache btrfs_work_helper
RIP: 0010:assert_eb_page_uptodate+0x3f/0x50
RSP: 0018:ffffa961440a7c68 EFLAGS: 00010246
RAX: 0017ffffc0002112 RBX: ffffe6e74453f9c0 RCX: 0000000000001000
RDX: ffffe6e74467c887 RSI: ffffe6e74453f9c0 RDI: ffff8d4c5efc2fc0
RBP: 0000000000000d56 R08: ffff8d4d4a224000 R09: 0000000000000000
R10: 00015817fa9d1ef0 R11: 000000000000000c R12: 00000000000007b1
R13: ffff8d4c5efc2fc0 R14: 0000000001500000 R15: 0000000001cb1000
FS: 0000000000000000(0000) GS:ffff8d4dbbd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff31d3448d8 CR3: 0000000118be8004 CR4: 0000000000370ee0
Call Trace:
extent_buffer_test_bit+0x3f/0x70
free_space_test_bit+0xa6/0xc0
load_free_space_tree+0x1f6/0x470
caching_thread+0x454/0x630
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? lock_release+0x1f0/0x2d0
btrfs_work_helper+0xf2/0x3e0
? lock_release+0x1f0/0x2d0
? finish_task_switch.isra.0+0xf9/0x3a0
process_one_work+0x26d/0x580
? process_one_work+0x580/0x580
worker_thread+0x55/0x3b0
? process_one_work+0x580/0x580
kthread+0xf0/0x120
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
This was partially fixed by c2e39305299f01 ("btrfs: clear extent buffer
uptodate when we fail to write it"), however all that fix did was keep
us from finding extent buffers after a failed writeout. It didn't keep
us from continuing to use a buffer that we already had found.
In this case we're searching the commit root to cache the block group,
so we can start committing the transaction and switch the commit root
and then start writing. After the switch we can look up an extent
buffer that hasn't been written yet and start processing that block
group. Then we fail to write that block out and clear Uptodate on the
page, and then we start spewing these errors.
Normally we're protected by the tree lock to a certain degree here. If
we read a block we have that block read locked, and we block the writer
from locking the block before we submit it for the write. However this
isn't necessarily fool proof because the read could happen before we do
the submit_bio and after we locked and unlocked the extent buffer.
Also in this particular case we have path->skip_locking set, so that
won't save us here. We'll simply get a block that was valid when we
read it, but became invalid while we were using it.
What we really want is to catch the case where we've "read" a block but
it's not marked Uptodate. On read we ClearPageError(), so if we're
!Uptodate and !Error we know we didn't do the right thing for reading
the page.
Fix this by checking !Uptodate && !Error, this way we will not complain
if our buffer gets invalidated while we're using it, and we'll maintain
the spirit of the check which is to make sure we have a fully in-cache
block while we're messing with it.
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
