Long saga. There have been days spent following this through dead end
after dead end in multi-GB event traces. This morning, after writing
a trace-cmd wrapper that enabled me to be more selective about XFS
trace points, I discovered that I could get just enough essential
tracepoints enabled that there was a 50:50 chance the fsx config
would fail at ~115k ops. If it didn't fail at op 115547, I stopped
fsx at op 115548 anyway.
That gave me two traces - one where the problem manifested, and one
where it didn't. After refining the traces to have the necessary
information, I found that in the failing case there was a real
extent in the COW fork compared to an unwritten extent in the
working case.
Walking back through the two traces to the point where the CWO fork
extents actually diverged, I found that the bad case had an extra
unwritten extent in it. This is likely because the bug it led me to
had triggered multiple times in those 115k ops, leaving stray
COW extents around. What I saw was a COW delalloc conversion to an
unwritten extent (as they should always be through
xfs_iomap_write_allocate()) resulted in a /written extent/:
xfs_writepage: dev 259:0 ino 0x83 pgoff 0x17000 size 0x79a00 offset 0 length 0
xfs_iext_remove: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/2 offset 32 block 152 count 20 flag 1 caller xfs_bmap_add_extent_delay_real
xfs_bmap_pre_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 4503599627239429 count 31 flag 0 caller xfs_bmap_add_extent_delay_real
xfs_bmap_post_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 121 count 51 flag 0 caller xfs_bmap_add_ex
Basically, Cow fork before:
0 1 32 52
+H+DDDDDDDDDDDD+UUUUUUUUUUU+
PREV RIGHT
COW delalloc conversion allocates:
1 32
+uuuuuuuuuuuu+
NEW
And the result according to the xfs_bmap_post_update trace was:
0 1 32 52
+H+wwwwwwwwwwwwwwwwwwwwwwww+
PREV
Which is clearly wrong - it should be a merged unwritten extent,
not an unwritten extent.
That lead me to look at the LEFT_FILLING|RIGHT_FILLING|RIGHT_CONTIG
case in xfs_bmap_add_extent_delay_real(), and sure enough, there's
the bug.
It takes the old delalloc extent (PREV) and adds the length of the
RIGHT extent to it, takes the start block from NEW, removes the
RIGHT extent and then updates PREV with the new extent.
What it fails to do is update PREV.br_state. For delalloc, this is
always XFS_EXT_NORM, while in this case we are converting the
delayed allocation to unwritten, so it needs to be updated to
XFS_EXT_UNWRITTEN. This LF|RF|RC case does not do this, and so
the resultant extent is always written.
And that's the bug I've been chasing for a week - a bmap btree bug,
not a reflink/dedupe/copy_file_range bug, but a BMBT bug introduced
with the recent in core extent tree scalability enhancements.
Signed-off-by: Dave Chinner <dchinner@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>
On a sub-page block size filesystem, fsx is failing with a data
corruption after a series of operations involving copying a file
with the destination offset beyond EOF of the destination of the file:
8093(157 mod 256): TRUNCATE DOWN from 0x7a120 to 0x50000 ******WWWW
8094(158 mod 256): INSERT 0x25000 thru 0x25fff (0x1000 bytes)
8095(159 mod 256): COPY 0x18000 thru 0x1afff (0x3000 bytes) to 0x2f400
8096(160 mod 256): WRITE 0x5da00 thru 0x651ff (0x7800 bytes) HOLE
8097(161 mod 256): COPY 0x2000 thru 0x5fff (0x4000 bytes) to 0x6fc00
The second copy here is beyond EOF, and it is to sub-page (4k) but
block aligned (1k) offset. The clone runs the EOF zeroing, landing
in a pre-existing post-eof delalloc extent. This zeroes the post-eof
extents in the page cache just fine, dirtying the pages correctly.
The problem is that xfs_reflink_remap_prep() now truncates the page
cache over the range that it is copying it to, and rounds that down
to cover the entire start page. This removes the dirty page over the
delalloc extent from the page cache without having written it back.
Hence later, when the page cache is flushed, the page at offset
0x6f000 has not been written back and hence exposes stale data,
which fsx trips over less than 10 operations later.
Fix this by changing xfs_reflink_remap_prep() to use
xfs_flush_unmap_range().
Signed-off-by: Dave Chinner <dchinner@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>
The extent shifting code uses a flush and invalidate mechainsm prior
to shifting extents around. This is similar to what
xfs_free_file_space() does, but it doesn't take into account things
like page cache vs block size differences, and it will fail if there
is a page that it currently busy.
xfs_flush_unmap_range() handles all of these cases, so just convert
xfs_prepare_shift() to us that mechanism rather than having it's own
special sauce.
Signed-off-by: Dave Chinner <dchinner@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>
The last AG may be very small comapred to all other AGs, and hence
AG reservations based on the superblock AG size may actually consume
more space than the AG actually has. This results on assert failures
like:
XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319
[ 48.932891] xfs_ag_resv_init+0x1bd/0x1d0
[ 48.933853] xfs_fs_reserve_ag_blocks+0x37/0xb0
[ 48.934939] xfs_mountfs+0x5b3/0x920
[ 48.935804] xfs_fs_fill_super+0x462/0x640
[ 48.936784] ? xfs_test_remount_options+0x60/0x60
[ 48.937908] mount_bdev+0x178/0x1b0
[ 48.938751] mount_fs+0x36/0x170
[ 48.939533] vfs_kern_mount.part.43+0x54/0x130
[ 48.940596] do_mount+0x20e/0xcb0
[ 48.941396] ? memdup_user+0x3e/0x70
[ 48.942249] ksys_mount+0xba/0xd0
[ 48.943046] __x64_sys_mount+0x21/0x30
[ 48.943953] do_syscall_64+0x54/0x170
[ 48.944835] entry_SYSCALL_64_after_hwframe+0x49/0xbe
Hence we need to ensure the finobt per-ag space reservations take
into account the size of the last AG rather than treat it like all
the other full size AGs.
Note that both refcountbt and rmapbt already take the size of the AG
into account via reading the AGF length directly.
Signed-off-by: Dave Chinner <dchinner@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>
When retrying a failed inode or dquot buffer,
xfs_buf_resubmit_failed_buffers() clears all the failed flags from
the inde/dquot log items. In doing so, it also drops all the
reference counts on the buffer that the failed log items hold. This
means it can drop all the active references on the buffer and hence
free the buffer before it queues it for write again.
Putting the buffer on the delwri queue takes a reference to the
buffer (so that it hangs around until it has been written and
completed), but this goes bang if the buffer has already been freed.
Hence we need to add the buffer to the delwri queue before we remove
the failed flags from the log items attached to the buffer to ensure
it always remains referenced during the resubmit process.
Reported-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dave Chinner <dchinner@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>
xfs_file_remap_range() is only used in fs/xfs/xfs_file.c, so make it
static.
This addresses a gcc warning when -Wmissing-prototypes is enabled.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Page writeback indirectly handles shared extents via the existence
of overlapping COW fork blocks. If COW fork blocks exist, writeback
always performs the associated copy-on-write regardless if the
underlying blocks are actually shared. If the blocks are shared,
then overlapping COW fork blocks must always exist.
fstests shared/010 reproduces a case where a buffered write occurs
over a shared block without performing the requisite COW fork
reservation. This ultimately causes writeback to the shared extent
and data corruption that is detected across md5 checks of the
filesystem across a mount cycle.
The problem occurs when a buffered write lands over a shared extent
that crosses an extent size hint boundary and that also happens to
have a partial COW reservation that doesn't cover the start and end
blocks of the data fork extent.
For example, a buffered write occurs across the file offset (in FSB
units) range of [29, 57]. A shared extent exists at blocks [29, 35]
and COW reservation already exists at blocks [32, 34]. After
accommodating a COW extent size hint of 32 blocks and the existing
reservation at offset 32, xfs_reflink_reserve_cow() allocates 32
blocks of reservation at offset 0 and returns with COW reservation
across the range of [0, 34]. The associated data fork extent is
still [29, 35], however, which isn't fully covered by the COW
reservation.
This leads to a buffered write at file offset 35 over a shared
extent without associated COW reservation. Writeback eventually
kicks in, performs an overwrite of the underlying shared block and
causes the associated data corruption.
Update xfs_reflink_reserve_cow() to accommodate the fact that a
delalloc allocation request may not fully cover the extent in the
data fork. Trim the data fork extent appropriately, just as is done
for shared extent boundaries and/or existing COW reservations that
happen to overlap the start of the data fork extent. This prevents
shared/010 failures due to data corruption on reflink enabled
filesystems.
Signed-off-by: Brian Foster <bfoster@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>
generic/070 on 64k block size filesystems is failing with a verifier
corruption on writeback or an attribute leaf block:
[ 94.973083] XFS (pmem0): Metadata corruption detected at xfs_attr3_leaf_verify+0x246/0x260, xfs_attr3_leaf block 0x811480
[ 94.975623] XFS (pmem0): Unmount and run xfs_repair
[ 94.976720] XFS (pmem0): First 128 bytes of corrupted metadata buffer:
[ 94.978270] 000000004b2e7b45: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00 ........;.......
[ 94.980268] 000000006b1db90b: 00 00 00 00 00 81 14 80 00 00 00 00 00 00 00 00 ................
[ 94.982251] 00000000433f2407: 22 7b 5c 82 2d 5c 47 4c bb 31 1c 37 fa a9 ce d6 "{\.-\GL.1.7....
[ 94.984157] 0000000010dc7dfb: 00 00 00 00 00 81 04 8a 00 0a 18 e8 dd 94 01 00 ................
[ 94.986215] 00000000d5a19229: 00 a0 dc f4 fe 98 01 68 f0 d8 07 e0 00 00 00 00 .......h........
[ 94.988171] 00000000521df36c: 0c 2d 32 e2 fe 20 01 00 0c 2d 58 65 fe 0c 01 00 .-2.. ...-Xe....
[ 94.990162] 000000008477ae06: 0c 2d 5b 66 fe 8c 01 00 0c 2d 71 35 fe 7c 01 00 .-[f.....-q5.|..
[ 94.992139] 00000000a4a6bca6: 0c 2d 72 37 fc d4 01 00 0c 2d d8 b8 f0 90 01 00 .-r7.....-......
[ 94.994789] XFS (pmem0): xfs_do_force_shutdown(0x8) called from line 1453 of file fs/xfs/xfs_buf.c. Return address = ffffffff815365f3
This is failing this check:
end = ichdr.freemap[i].base + ichdr.freemap[i].size;
if (end < ichdr.freemap[i].base)
>>>>> return __this_address;
if (end > mp->m_attr_geo->blksize)
return __this_address;
And from the buffer output above, the freemap array is:
freemap[0].base = 0x00a0
freemap[0].size = 0xdcf4 end = 0xdd94
freemap[1].base = 0xfe98
freemap[1].size = 0x0168 end = 0x10000
freemap[2].base = 0xf0d8
freemap[2].size = 0x07e0 end = 0xf8b8
These all look valid - the block size is 0x10000 and so from the
last check in the above verifier fragment we know that the end
of freemap[1] is valid. The problem is that end is declared as:
uint16_t end;
And (uint16_t)0x10000 = 0. So we have a verifier bug here, not a
corruption. Fix the verifier to use uint32_t types for the check and
hence avoid the overflow.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=201577
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Use DUMP_PREFIX_OFFSET when printing hex dumps of corrupt buffers
because modern Linux now prints a 32-bit hash of our 64-bit pointer when
using DUMP_PREFIX_ADDRESS:
00000000b4bb4297: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00 ........;.......
00000005ec77e26: 00 00 00 00 02 d0 5a 00 00 00 00 00 00 00 00 00 ......Z.........
000000015938018: 21 98 e8 b4 fd de 4c 07 bc ea 3c e5 ae b4 7c 48 !.....L...<...|H
This is totally worthless for a sequential dump since we probably only
care about tracking the buffer offsets and afaik there's no way to
recover the actual pointer from the hashed value.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In this function, once 'buf' has been allocated, we unconditionally
return 0.
However, 'error' is set to some error codes in several error handling
paths.
Before commit 232b51948b ("xfs: simplify the xfs_getbmap interface")
this was not an issue because all error paths were returning directly,
but now that some cleanup at the end may be needed, we must propagate the
error code.
Fixes: 232b51948b ("xfs: simplify the xfs_getbmap interface")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
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>
Rework the vfs_clone_file_range and vfs_dedupe_file_range infrastructure to use
a common .remap_file_range method and supply generic bounds and sanity checking
functions that are shared with the data write path. The current VFS
infrastructure has problems with rlimit, LFS file sizes, file time stamps,
maximum filesystem file sizes, stripping setuid bits, etc and so they are
addressed in these commits.
We also introduce the ability for the ->remap_file_range methods to return short
clones so that clones for vfs_copy_file_range() don't get rejected if the entire
range can't be cloned. It also allows filesystems to sliently skip deduplication
of partial EOF blocks if they are not capable of doing so without requiring
errors to be thrown to userspace.
All existing filesystems are converted to user the new .remap_file_range method,
and both XFS and ocfs2 are modified to make use of the new generic checking
infrastructure.
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Merge tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull vfs dedup fixes from Dave Chinner:
"This reworks the vfs data cloning infrastructure.
We discovered many issues with these interfaces late in the 4.19 cycle
- the worst of them (data corruption, setuid stripping) were fixed for
XFS in 4.19-rc8, but a larger rework of the infrastructure fixing all
the problems was needed. That rework is the contents of this pull
request.
Rework the vfs_clone_file_range and vfs_dedupe_file_range
infrastructure to use a common .remap_file_range method and supply
generic bounds and sanity checking functions that are shared with the
data write path. The current VFS infrastructure has problems with
rlimit, LFS file sizes, file time stamps, maximum filesystem file
sizes, stripping setuid bits, etc and so they are addressed in these
commits.
We also introduce the ability for the ->remap_file_range methods to
return short clones so that clones for vfs_copy_file_range() don't get
rejected if the entire range can't be cloned. It also allows
filesystems to sliently skip deduplication of partial EOF blocks if
they are not capable of doing so without requiring errors to be thrown
to userspace.
Existing filesystems are converted to user the new remap_file_range
method, and both XFS and ocfs2 are modified to make use of the new
generic checking infrastructure"
* tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (28 commits)
xfs: remove [cm]time update from reflink calls
xfs: remove xfs_reflink_remap_range
xfs: remove redundant remap partial EOF block checks
xfs: support returning partial reflink results
xfs: clean up xfs_reflink_remap_blocks call site
xfs: fix pagecache truncation prior to reflink
ocfs2: remove ocfs2_reflink_remap_range
ocfs2: support partial clone range and dedupe range
ocfs2: fix pagecache truncation prior to reflink
ocfs2: truncate page cache for clone destination file before remapping
vfs: clean up generic_remap_file_range_prep return value
vfs: hide file range comparison function
vfs: enable remap callers that can handle short operations
vfs: plumb remap flags through the vfs dedupe functions
vfs: plumb remap flags through the vfs clone functions
vfs: make remap_file_range functions take and return bytes completed
vfs: remap helper should update destination inode metadata
vfs: pass remap flags to generic_remap_checks
vfs: pass remap flags to generic_remap_file_range_prep
vfs: combine the clone and dedupe into a single remap_file_range
...
Now that the vfs remap helper dirties the inode [cm]time for us, xfs no
longer needs to do that on its own.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Since xfs_file_remap_range is a thin wrapper, move the contents of
xfs_reflink_remap_range into the shell. This cuts down on the vfs
calls being made from internal xfs code.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Now that we've moved the partial EOF block checks to the VFS helpers, we
can remove the redundant functionality from XFS.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Back when the XFS reflink code only supported clone_file_range, we were
only able to return zero or negative error codes to userspace. However,
now that copy_file_range (which returns bytes copied) can use XFS'
clone_file_range, we have the opportunity to return partial results.
For example, if userspace sends a 1GB clone request and we run out of
space halfway through, we at least can tell userspace that we completed
512M of that request like a regular write.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the offset <-> blocks unit conversions into
xfs_reflink_remap_blocks to make the call site less ugly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Prior to remapping blocks, it is necessary to remove pages from the
destination file's page cache. Unfortunately, the truncation is not
aggressive enough -- if page size > block size, we'll end up zeroing
subpage blocks instead of removing them. So, round the start offset
down and the end offset up to page boundaries. We already wrote all
the dirty data so the larger range shouldn't be a problem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Since the remap prep function can update the length of the remap
request, we can change this function to return the usual return status
instead of the odd behavior it has now.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Change the remap_file_range functions to take a number of bytes to
operate upon and return the number of bytes they operated on. This is a
requirement for allowing fs implementations to return short clone/dedupe
results to the user, which will enable us to obey resource limits in a
graceful manner.
A subsequent patch will enable copy_file_range to signal to the
->clone_file_range implementation that it can handle a short length,
which will be returned in the function's return value. For now the
short return is not implemented anywhere so the behavior won't change --
either copy_file_range manages to clone the entire range or it tries an
alternative.
Neither clone ioctl can take advantage of this, alas.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Extend generic_remap_file_range_prep to handle inode metadata updates
when remapping into a file. If the operation can possibly alter the
file contents, we must update the ctime and mtime and remove security
privileges, just like we do for regular file writes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Plumb the remap flags through the filesystem from the vfs function
dispatcher all the way to the prep function to prepare for behavior
changes in subsequent patches.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Combine the clone_file_range and dedupe_file_range operations into a
single remap_file_range file operation dispatch since they're
fundamentally the same operation. The differences between the two can
be made in the prep functions.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The vfs_clone_file_prep is a generic function to be called by filesystem
implementations only. Rename the prefix to generic_ and make it more
clear that it applies to remap operations, not just clones.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the file range checks from vfs_clone_file_prep into a separate
generic_remap_checks function so that all the checks are collected in a
central location. This forms the basis for adding more checks from
generic_write_checks that will make cloning's input checking more
consistent with write input checking.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
In the typical unmount case, the AIL is forced out by the unmount
sequence before the xfsaild task is stopped. Since AIL items are
removed on writeback completion, this means that the AIL
->ail_buf_list delwri queue has been drained. This is not always
true in the shutdown case, however.
It's possible for buffers to sit on a delwri queue for a period of
time across submission attempts if said items are locked or have
been relogged and pinned since first added to the queue. If the
attempt to log such an item results in a log I/O error, the error
processing can shutdown the fs, remove the item from the AIL, stale
the buffer (dropping the LRU reference) and clear its delwri queue
state. The latter bit means the buffer will be released from a
delwri queue on the next submission attempt, but this might never
occur if the filesystem has shutdown and the AIL is empty.
This means that such buffers are held indefinitely by the AIL delwri
queue across destruction of the AIL. Aside from being a memory leak,
these buffers can also hold references to in-core perag structures.
The latter problem manifests as a generic/475 failure, reproducing
the following asserts at unmount time:
XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0,
file: fs/xfs/xfs_mount.c, line: 151
XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0,
file: fs/xfs/xfs_mount.c, line: 132
To prevent this problem, clear the AIL delwri queue as a final step
before xfsaild() exit. The !empty state should never occur in the
normal case, so add an assert to catch unexpected problems going
forward.
[dgc: add comment explaining need for xfs_buf_delwri_cancel() after
calling xfs_buf_delwri_submit_nowait().]
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Most offset macro mess is used in xfs_stats_format() only, and we can
simply get the right offsets using offsetof(), instead of several macros
to mark the offsets inside __xfsstats structure.
Replace all XFSSTAT_END_* macros by a single helper macro to get the
right offset into __xfsstats, and use this helper in xfs_stats_format()
directly.
The quota stats code, still looks a bit cleaner when using XFSSTAT_*
macros, so, this patch also defines XFSSTAT_START_XQMSTAT and
XFSSTAT_END_XQMSTAT locally to that code. This also should prevent
offset mistakes when updates are done into __xfsstats.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The addition of FIBT, RMAP and REFCOUNT changed the offsets into
__xfssats structure.
This caused xqmstat_proc_show() to display garbage data via
/proc/fs/xfs/xqmstat, once it relies on the offsets marked via macros.
Fix it.
Fixes: 00f4e4f9 xfs: add rmap btree stats infrastructure
Fixes: aafc3c24 xfs: support the XFS_BTNUM_FINOBT free inode btree type
Fixes: 46eeb521 xfs: introduce refcount btree definitions
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When looking at a 4.18 based KASAN use after free report, I noticed
that racing xfs_buf_rele() may race on dropping the last reference
to the buffer and taking the buffer lock. This was the symptom
displayed by the KASAN report, but the actual issue that was
reported had already been fixed in 4.19-rc1 by commit e339dd8d8b
("xfs: use sync buffer I/O for sync delwri queue submission").
Despite this, I think there is still an issue with xfs_buf_rele()
in this code:
release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock);
spin_lock(&bp->b_lock);
if (!release) {
.....
If two threads race on the b_lock after both dropping a reference
and one getting dropping the last reference so release = true, we
end up with:
CPU 0 CPU 1
atomic_dec_and_lock()
atomic_dec_and_lock()
spin_lock(&bp->b_lock)
spin_lock(&bp->b_lock)
<spins>
<release = true bp->b_lru_ref = 0>
<remove from lists>
freebuf = true
spin_unlock(&bp->b_lock)
xfs_buf_free(bp)
<gets lock, reading and writing freed memory>
<accesses freed memory>
spin_unlock(&bp->b_lock) <reads/writes freed memory>
IOWs, we can't safely take bp->b_lock after dropping the hold
reference because the buffer may go away at any time after we
drop that reference. However, this can be fixed simply by taking the
bp->b_lock before we drop the reference.
It is safe to nest the pag_buf_lock inside bp->b_lock as the
pag_buf_lock is only used to serialise against lookup in
xfs_buf_find() and no other locks are held over or under the
pag_buf_lock there. Make this clear by documenting the buffer lock
orders at the top of the file.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com
Signed-off-by: Dave Chinner <david@fromorbit.com>
This patch adds xfs_attr_remove_args. These sub-routines remove
the attributes specified in @args. We will use this later for setting
parent pointers as a deferred attribute operation.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This patch adds xfs_attr_set_args and xfs_bmap_set_attrforkoff.
These sub-routines set the attributes specified in @args.
We will use this later for setting parent pointers as a deferred
attribute operation.
[dgc: remove attr fork init code from xfs_attr_set_args().]
[dgc: xfs_attr_try_sf_addname() NULLs args.trans after commit.]
[dgc: correct sf add error handling.]
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This patch adds a subroutine xfs_attr_try_sf_addname
used by xfs_attr_set. This subrotine will attempt to
add the attribute name specified in args in shortform,
as well and perform error handling previously done in
xfs_attr_set.
This patch helps to pre-simplify xfs_attr_set for reviewing
purposes and reduce indentation. New function will be added
in the next patch.
[dgc: moved commit to helper function, too.]
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This patch moves fs/xfs/xfs_attr.h to fs/xfs/libxfs/xfs_attr.h
since xfs_attr.c is in libxfs. We will need these later in
xfsprogs.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The kernel only issues a log message that it's been shut down when
the filesystem triggers a shutdown itself. Hence there is no trace
in the log when a shutdown is triggered manually from userspace.
This can make it hard to see sequence of events in the log when
things go wrong, so make sure we always log a message when a
shutdown is run.
While there, clean up the logic flow so we don't have to continually
check if the shutdown trigger was user initiated before logging
shutdown messages.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We don't handle buffer state properly in online repair's findroot
routine. If a buffer already has b_ops set, we don't ever want to touch
that, and we don't want to call the read verifiers on a buffer that
could be dirty (CRCs are only recomputed during log checkpoints).
Therefore, be more careful about what we do with a buffer -- if someone
else already attached ops that are not the ones for this btree type,
just ignore the buffer. We only attach our btree type's buf ops if it
matches the magic/uuid and structure checks.
We also modify xfs_buf_read_map to allow callers to set buffer ops on a
DONE buffer with NULL ops so that repair doesn't leave behind buffers
which won't have buffers attached to them.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
If a caller supplies buffer ops when trying to read a buffer and the
buffer doesn't already have buf ops assigned, ensure that the ops are
assigned to the buffer and the verifier is run on that buffer.
Note that current XFS code is careful to assign buffer ops after a
xfs_{trans_,}buf_read call in which ops were not supplied. However, we
should apply ops defensively in case there is ever a coding mistake; and
an upcoming repair patch will need to be able to read a buffer without
assigning buf ops.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
In xrep_findroot_block, if we find a candidate root block with sibling
pointers or sibling blocks on the same tree level, we should not return
that block as a tree root because root blocks cannot have siblings.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Needed by userspace programs that call fstatfs().
It'd be natural to publish XFS_SB_MAGIC in uapi, but while these two
have identical values, they have different semantic meaning: one is
an enum cookie meant for statfs, the other a signature of the
on-disk format.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Instead of just asserting that we have no delalloc space dangling
in an inode that gets freed print the actual offenders for debug
mode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We should want to write directly into the data fork for blocks that don't
have an extent in the COW fork covering them yet.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We only need to allocate blocks for zeroing for reflink inodes,
and for we currently have a special case for reflink files in
the otherwise direct I/O path that I'd like to get rid of.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The option to enable unwritten extents was made default in 2003,
removed from mkfs in 2007, and cannot be disabled in v5. We also
rely on it for a lot of common functionality, so filesystems without
it will run a completely untested and buggy code path. Enabling the
support also is a simple bit flip using xfs_db, so legacy file
systems can still be brought forward.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The invalid state isn't any different from a hole, so merge the two
states. Use the more descriptive hole name, but keep it as the first
value of the enum to catch uninitialized fields.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When reflinking sub-file ranges, a data corruption can occur when
the source file range includes a partial EOF block. This shares the
unknown data beyond EOF into the second file at a position inside
EOF, exposing stale data in the second file.
XFS only supports whole block sharing, but we still need to
support whole file reflink correctly. Hence if the reflink
request includes the last block of the souce file, only proceed with
the reflink operation if it lands at or past the destination file's
current EOF. If it lands within the destination file EOF, reject the
entire request with -EINVAL and make the caller go the hard way.
This avoids the data corruption vector, but also avoids disruption
of returning EINVAL to userspace for the common case of whole file
cloning.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
A deduplication data corruption is Exposed by fstests generic/505 on
XFS. It is caused by extending the block match range to include the
partial EOF block, but then allowing unknown data beyond EOF to be
considered a "match" to data in the destination file because the
comparison is only made to the end of the source file. This corrupts
the destination file when the source extent is shared with it.
XFS only supports whole block dedupe, but we still need to appear to
support whole file dedupe correctly. Hence if the dedupe request
includes the last block of the souce file, don't include it in the
actual XFS dedupe operation. If the rest of the range dedupes
successfully, then report the partial last block as deduped, too, so
that userspace sees it as a successful dedupe rather than return
EINVAL because we can't dedupe unaligned blocks.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Before cloning into a file, update the ctime and remove sensitive
attributes like suid, just like we'd do for a regular file write.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When we're reflinking between two files and the destination file range
is well beyond the destination file's EOF marker, zero any posteof
speculative preallocations in the destination file so that we don't
expose stale disk contents. The previous strategy of trying to clear
the preallocations does not work if the destination file has the
PREALLOC flag set.
Uncovered by shared/010.
Reported-by: Zorro Lang <zlang@redhat.com>
Bugzilla-id: https://bugzilla.kernel.org/show_bug.cgi?id=201259
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
