- 24 Mar, 2018 16 commits
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Dave Chinner authored
We recently came across a V4 filesystem causing memory corruption due to a newly allocated inode being setup twice and being added to the superblock inode list twice. From code inspection, the only way this could happen is if a newly allocated inode was not marked as free on disk (i.e. di_mode wasn't zero). Running the metadump on an upstream debug kernel fails during inode allocation like so: XFS: Assertion failed: ip->i_d.di_nblocks == 0, file: fs/xfs/xfs_inod= e.c, line: 838 ------------[ cut here ]------------ kernel BUG at fs/xfs/xfs_message.c:114! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 11 PID: 3496 Comm: mkdir Not tainted 4.16.0-rc5-dgc #442 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/0= 1/2014 RIP: 0010:assfail+0x28/0x30 RSP: 0018:ffffc9000236fc80 EFLAGS: 00010202 RAX: 00000000ffffffea RBX: 0000000000004000 RCX: 0000000000000000 RDX: 00000000ffffffc0 RSI: 000000000000000a RDI: ffffffff8227211b RBP: ffffc9000236fce8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000bec R11: f000000000000000 R12: ffffc9000236fd30 R13: ffff8805c76bab80 R14: ffff8805c77ac800 R15: ffff88083fb12e10 FS: 00007fac8cbff040(0000) GS:ffff88083fd00000(0000) knlGS:0000000000000= 000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffa6783ff8 CR3: 00000005c6e2b003 CR4: 00000000000606e0 Call Trace: xfs_ialloc+0x383/0x570 xfs_dir_ialloc+0x6a/0x2a0 xfs_create+0x412/0x670 xfs_generic_create+0x1f7/0x2c0 ? capable_wrt_inode_uidgid+0x3f/0x50 vfs_mkdir+0xfb/0x1b0 SyS_mkdir+0xcf/0xf0 do_syscall_64+0x73/0x1a0 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Extracting the inode number we crashed on from an event trace and looking at it with xfs_db: xfs_db> inode 184452204 xfs_db> p core.magic = 0x494e core.mode = 0100644 core.version = 2 core.format = 2 (extents) core.nlinkv2 = 1 core.onlink = 0 ..... Confirms that it is not a free inode on disk. xfs_repair also trips over this inode: ..... zero length extent (off = 0, fsbno = 0) in ino 184452204 correcting nextents for inode 184452204 bad attribute fork in inode 184452204, would clear attr fork bad nblocks 1 for inode 184452204, would reset to 0 bad anextents 1 for inode 184452204, would reset to 0 imap claims in-use inode 184452204 is free, would correct imap would have cleared inode 184452204 ..... disconnected inode 184452204, would move to lost+found And so we have a situation where the directory structure and the inobt thinks the inode is free, but the inode on disk thinks it is still in use. Where this corruption came from is not possible to diagnose, but we can detect it and prevent the kernel from oopsing on lookup. The reproducer now results in: $ sudo mkdir /mnt/scratch/{0,1,2,3,4,5}{0,1,2,3,4,5} mkdir: cannot create directory =E2=80=98/mnt/scratch/00=E2=80=99: File ex= ists mkdir: cannot create directory =E2=80=98/mnt/scratch/01=E2=80=99: File ex= ists mkdir: cannot create directory =E2=80=98/mnt/scratch/03=E2=80=99: Structu= re needs cleaning mkdir: cannot create directory =E2=80=98/mnt/scratch/04=E2=80=99: Input/o= utput error mkdir: cannot create directory =E2=80=98/mnt/scratch/05=E2=80=99: Input/o= utput error .... And this corruption shutdown: [ 54.843517] XFS (loop0): Corruption detected! Free inode 0xafe846c not= marked free on disk [ 54.845885] XFS (loop0): Internal error xfs_trans_cancel at line 1023 = of file fs/xfs/xfs_trans.c. Caller xfs_create+0x425/0x670 [ 54.848994] CPU: 10 PID: 3541 Comm: mkdir Not tainted 4.16.0-rc5-dgc #= 443 [ 54.850753] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIO= S 1.10.2-1 04/01/2014 [ 54.852859] Call Trace: [ 54.853531] dump_stack+0x85/0xc5 [ 54.854385] xfs_trans_cancel+0x197/0x1c0 [ 54.855421] xfs_create+0x425/0x670 [ 54.856314] xfs_generic_create+0x1f7/0x2c0 [ 54.857390] ? capable_wrt_inode_uidgid+0x3f/0x50 [ 54.858586] vfs_mkdir+0xfb/0x1b0 [ 54.859458] SyS_mkdir+0xcf/0xf0 [ 54.860254] do_syscall_64+0x73/0x1a0 [ 54.861193] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 54.862492] RIP: 0033:0x7fb73bddf547 [ 54.863358] RSP: 002b:00007ffdaa553338 EFLAGS: 00000246 ORIG_RAX: 0000= 000000000053 [ 54.865133] RAX: ffffffffffffffda RBX: 00007ffdaa55449a RCX: 00007fb73= bddf547 [ 54.866766] RDX: 0000000000000001 RSI: 00000000000001ff RDI: 00007ffda= a55449a [ 54.868432] RBP: 00007ffdaa55449a R08: 00000000000001ff R09: 00005623a= 8670dd0 [ 54.870110] R10: 00007fb73be72d5b R11: 0000000000000246 R12: 000000000= 00001ff [ 54.871752] R13: 00007ffdaa5534b0 R14: 0000000000000000 R15: 00007ffda= a553500 [ 54.873429] XFS (loop0): xfs_do_force_shutdown(0x8) called from line 1= 024 of file fs/xfs/xfs_trans.c. Return address = ffffffff814cd050 [ 54.882790] XFS (loop0): Corruption of in-memory data detected. Shutt= ing down filesystem [ 54.884597] XFS (loop0): Please umount the filesystem and rectify the = problem(s) Note that this crash is only possible on v4 filesystemsi or v5 filesystems mounted with the ikeep mount option. For all other V5 filesystems, this problem cannot occur because we don't read inodes we are allocating from disk - we simply overwrite them with the new inode information. Signed-Off-By:Dave Chinner <dchinner@redhat.com> Reviewed-by:
Carlos Maiolino <cmaiolino@redhat.com> Tested-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
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Darrick J. Wong authored
In xfs_scrub_iallocbt_xref_rmap_inodes we're checking inodes against rmap records, so we should use xfs_scrub_btree_xref_set_corrupt if we encounter discrepancies here so that we know that it's a cross referencing error, not necessarily a corruption in the inobt itself. The userspace xfs_scrub program will try to repair outright corruptions in the agi/inobt prior to phase 3 so that the inode scan will proceed. If only a cross-referencing error is noted, the repair program defers the repair attempt until it can check the other space metadata at least once. It is therefore essential that the inobt scrubber can correctly distinguish between corruptions and "unable to cross-reference something else with this inobt". The same reasoning applies to "xfs: record inode buf errors as a xref error in inobt scrubber". Signed-off-by:
Brian Foster <bfoster@redhat.com>
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Darrick J. Wong authored
If a directory's parent inode pointer doesn't point to an inode, the directory should be flagged as corrupt. Enable IGET_UNTRUSTED here so that _iget will return -EINVAL if the inobt does not confirm that the inode is present and allocated and we can flag the directory corruption. Signed-off-by:
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Darrick J. Wong authored
When we're verifying inode buffers, sanity-check the unlinked pointer. We don't want to run the risk of trying to purge something that's obviously broken. Signed-off-by:
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Darrick J. Wong authored
Extent size hint validation is used by scrub to decide if there's an error, and it will be used by repair to decide to remove the hint. Since these use the same validation functions, move them to libxfs. Signed-off-by:
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Darrick J. Wong authored
During the inode btree scrubs we try to confirm the freemask bits against the inode records. If the inode buffer read fails, this is a cross-referencing error, not a corruption of the inode btree itself. Use the xref_process_error call here. Found via core.version middlebit fuzz in xfs/415. The userspace xfs_scrub program will try to repair outright corruptions in the agi/inobt prior to phase 3 so that the inode scan will proceed. If only a cross-referencing error is noted, the repair program defers the repair attempt until it can check the other space metadata at least once. It is therefore essential that the inobt scrubber can correctly distinguish between corruptions and "unable to cross-reference something else with this inobt". Signed-off-by:
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Darrick J. Wong authored
Now that we no longer do raw inode buffer scrubbing, the bp parameter is no longer used anywhere we're dealing with an inode, so remove it and all the useless NULL parameters that go with it. Signed-off-by:
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Darrick J. Wong authored
The inode scrubber tries to _iget the inode prior to running checks. If that _iget call fails with corruption errors that's an automatic fail, regardless of whether it was the inode buffer read verifier, the ifork verifier, or the ifork formatter that errored out. Therefore, get rid of the raw mode scrub code because it's not needed. Found by trying to fix some test failures in xfs/379 and xfs/415. Signed-off-by:
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Darrick J. Wong authored
When we're scanning an extent mapping inode fork, ensure that every rmap record for this ifork has a corresponding bmbt record too. This (mostly) provides the ability to cross-reference rmap records with bmap data. The rmap scrubber cannot do the xref on its own because that requires taking an ilock with the agf lock held, which violates our locking order rules (inode, then agf). Note that we only do this for forks that are in btree format due to the increased complexity; or forks that should have data but suspiciously have zero extents because the inode could have just had its iforks zapped by the inode repair code and now we need to reclaim the old extents. Signed-off-by:
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Darrick J. Wong authored
When the inode buffer verifier encounters an error, it's much more helpful to print a buffer from the offending inode instead of just the start of the inode chunk buffer. Signed-off-by:
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Darrick J. Wong authored
Refactor some of the inode verifier failure logging call sites to use the new xfs_inode_verifier_error method which dumps the offending buffer as well as the code location of the failed check. This trims the output, makes it clearer to the admin that repair must be run, and gives the developers more details to work from. Signed-off-by:
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Darrick J. Wong authored
Refactor the bmap validator into a more complete helper that looks for extents that run off the end of the device, overflow into the next AG, or have invalid flag states. Signed-off-by:
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Darrick J. Wong authored
In xfs_dir2_data_use_free, we examine on-disk metadata and ASSERT if it doesn't make sense. Since a carefully crafted fuzzed image can cause the kernel to crash after blowing a bunch of assertions, let's move those checks into a validator function and rig everything up to return EFSCORRUPTED to userspace. Found by lastbit fuzzing ltail.bestcount via xfs/391. Signed-off-by:
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Brian Foster authored
The struct xfs_agfl v5 header was originally introduced with unexpected padding that caused the AGFL to operate with one less slot than intended. The header has since been packed, but the fix left an incompatibility for users who upgrade from an old kernel with the unpacked header to a newer kernel with the packed header while the AGFL happens to wrap around the end. The newer kernel recognizes one extra slot at the physical end of the AGFL that the previous kernel did not. The new kernel will eventually attempt to allocate a block from that slot, which contains invalid data, and cause a crash. This condition can be detected by comparing the active range of the AGFL to the count. While this detects a padding mismatch, it can also trigger false positives for unrelated flcount corruption. Since we cannot distinguish a size mismatch due to padding from unrelated corruption, we can't trust the AGFL enough to simply repopulate the empty slot. Instead, avoid unnecessarily complex detection logic and and use a solution that can handle any form of flcount corruption that slips through read verifiers: distrust the entire AGFL and reset it to an empty state. Any valid blocks within the AGFL are intentionally leaked. This requires xfs_repair to rectify (which was already necessary based on the state the AGFL was found in). The reset mitigates the side effect of the padding mismatch problem from a filesystem crash to a free space accounting inconsistency. The generic approach also means that this patch can be safely backported to kernels with or without a packed struct xfs_agfl. Check the AGF for an invalid freelist count on initial read from disk. If detected, set a flag on the xfs_perag to indicate that a reset is required before the AGFL can be used. In the first transaction that attempts to use a flagged AGFL, reset it to empty, warn the user about the inconsistency and allow the freelist fixup code to repopulate the AGFL with new blocks. The xfs_perag flag is cleared to eliminate the need for repeated checks on each block allocation operation. This allows kernels that include the packing fix commit 96f859d5 ("libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct") to handle older unpacked AGFL formats without a filesystem crash. Suggested-by:
Dave Chinner <david@fromorbit.com> Signed-off-by:
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Christoph Hellwig authored
Instead split out a __xfs_log_fore_lsn helper that gets called again with the already_slept flag set to true in case we had to sleep. This prepares for aio_fsync support. Signed-off-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
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Christoph Hellwig authored
Use the the smallest possible loop as preable to find the correct iclog buffer, and then use gotos for unwinding to straighten the code. Also fix the top of function comment while we're at it. Signed-off-by:
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- 15 Mar, 2018 6 commits
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Christoph Hellwig authored
Use xfs_iext_prev_extent to skip to the previous extent instead of opencoding it. Signed-off-by:
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Christoph Hellwig authored
Simplify the control flow a bit in preparation for O_ATOMIC-related changes. Signed-off-by:
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Christoph Hellwig authored
This helper doesn't add any real value over just calling iomap_zero_range directly, so remove it. Signed-off-by:
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Christoph Hellwig authored
Now that we convert COW preallocations from unwritten to real on every call this function needs to be called with the ilock held exclusively. Fortunately we already do that, but update the assert to match. Signed-off-by:
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Christoph Hellwig authored
There is no reason to get a mapping bigger than what we were asked for. Signed-off-by:
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Christoph Hellwig authored
i_cnextents does not include delayed allocated extents, so switch to the inode fork size check that we already use in other places instead. Signed-off-by:
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- 14 Mar, 2018 6 commits
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Christoph Hellwig authored
Streamline the conditionals so that it is more obvious which specific case form the top of the function comments is being handled. Use gotos only for early returns. Signed-off-by:
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Christoph Hellwig authored
Switch to a single interface for flushing the log to a specific LSN, which gives consistent trace point coverage and a less confusing interface. The was only a single user of the previous xfs_log_force_lsn function, which now also passes a NULL log_flushed argument. Signed-off-by:
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Christoph Hellwig authored
Switch to a single interface for flushing the whole log, which gives consistent trace point coverage, and removes the unused log_flushed argument for the previous _xfs_log_force callers. Signed-off-by:
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Christoph Hellwig authored
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Christoph Hellwig authored
The function now does something, and that something is central to our inode logging scheme. Signed-off-by:
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Christoph Hellwig authored
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- 12 Mar, 2018 12 commits
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Brian Foster authored
The rmapbt perag metadata reservation reserves blocks for the reverse mapping btree (rmapbt). Since the rmapbt uses blocks from the agfl and perag accounting is updated as blocks are allocated from the allocation btrees, the reservation actually accounts blocks as they are allocated to (or freed from) the agfl rather than the rmapbt itself. While this works for blocks that are eventually used for the rmapbt, not all agfl blocks are destined for the rmapbt. Blocks that are allocated to the agfl (and thus "reserved" for the rmapbt) but then used by another structure leads to a growing inconsistency over time between the runtime tracking of rmapbt usage vs. actual rmapbt usage. Since the runtime tracking thinks all agfl blocks are rmapbt blocks, it essentially believes that less future reservation is required to satisfy the rmapbt than what is actually necessary. The inconsistency is rectified across mount cycles because the perag reservation is initialized based on the actual rmapbt usage at mount time. The problem, however, is that the excessive drain of the reservation at runtime opens a window to allocate blocks for other purposes that might be required for the rmapbt on a subsequent mount. This problem can be demonstrated by a simple test that runs an allocation workload to consume agfl blocks over time and then observe the difference in the agfl reservation requirement across an unmount/mount cycle: mount ...: xfs_ag_resv_init: ... resv 3193 ask 3194 len 3194 ... ... : xfs_ag_resv_alloc_extent: ... resv 2957 ask 3194 len 1 umount...: xfs_ag_resv_free: ... resv 2956 ask 3194 len 0 mount ...: xfs_ag_resv_init: ... resv 3052 ask 3194 len 3194 As the above tracepoints show, the reservation requirement reduces from 3194 blocks to 2956 blocks as the workload runs. Without any other changes in the filesystem, the same reservation requirement jumps from 2956 to 3052 blocks over a umount/mount cycle. To address this divergence, update the RMAPBT reservation to account blocks used for the rmapbt only rather than all blocks filled into the agfl. This patch makes several high-level changes toward that end: 1.) Reintroduce an AGFL reservation type to serve as an accounting no-op for blocks allocated to (or freed from) the AGFL. 2.) Invoke RMAPBT usage accounting from the actual rmapbt block allocation path rather than the AGFL allocation path. The first change is required because agfl blocks are considered free blocks throughout their lifetime. The perag reservation subsystem is invoked unconditionally by the allocation subsystem, so we need a way to tell the perag subsystem (via the allocation subsystem) to not make any accounting changes for blocks filled into the AGFL. The second change causes the in-core RMAPBT reservation usage accounting to remain consistent with the on-disk state at all times and eliminates the risk of leaving the rmapbt reservation underfilled. Signed-off-by: -
Brian Foster authored
The AGFL perag reservation type accounts all allocations that feed into (or are released from) the allocation group free list (agfl). The purpose of the reservation is to support worst case conditions for the reverse mapping btree (rmapbt). As such, the agfl reservation usage accounting only considers rmapbt usage when the in-core counters are initialized at mount time. This implementation inconsistency leads to divergence of the in-core and on-disk usage accounting over time. In preparation to resolve this inconsistency and adjust the AGFL reservation into an rmapbt specific reservation, rename the AGFL reservation type and associated accounting fields to something more rmapbt-specific. Also fix up a couple tracepoints that incorrectly use the AGFL reservation type to pass the agfl state of the associated extent where the raw reservation type is expected. Note that this patch does not change perag reservation behavior. Signed-off-by:
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Brian Foster authored
The extent swap mechanism requires a unique implementation for rmapbt enabled filesystems. Because the rmapbt tracks extent owner information, extent swap must individually unmap and remap each extent between the two inodes. The rmapbt extent swap transaction block reservation currently accounts for the worst case bmapbt block and rmapbt block consumption based on the extent count of each inode. There is a corner case that exists due to the extent swap implementation that is not covered by this reservation, however. If one of the associated inodes is just over the max extent count used for extent format inodes (i.e., the inode is in btree format by a single extent), the unmap/remap cycle of the extent swap can bounce the inode between extent and btree format multiple times, almost as many times as there are extents in the inode (if the opposing inode happens to have one less, for example). Each back and forth cycle involves a block free and allocation, which isn't a problem except for that the initial transaction reservation must account for the total number of block allocations performed by the chain of deferred operations. If not, a block reservation overrun occurs and the filesystem shuts down. Update the rmapbt extent swap block reservation to check for this situation and add some block reservation slop to ensure the entire operation succeeds. We'd never likely require reservation for both inodes as fsr wouldn't defrag the file in that case, but the additional reservation is constrained by the data fork size so be cautious and check for both. Signed-off-by:
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Brian Foster authored
The ->t_blk_res_used field tracks how many blocks have been used in the current transaction. This should never exceed the block reservation (->t_blk_res) for a particular transaction. We currently assert this condition in the transaction block accounting code, but otherwise take no additional action should this situation occur. The overrun generally has no effect if space ends up being available and the associated transaction commits. If the transaction is duplicated, however, the current block usage is used to determine the remaining block reservation to be transferred to the new transaction. If usage exceeds reservation, this calculation underflows and creates a transaction with an invalid and excessive reservation. When the second transaction commits, the release of unused blocks corrupts the in-core free space counters. With lazy superblock accounting enabled, this inconsistency eventually trickles to the on-disk superblock and corrupts the filesystem. Replace the transaction block usage accounting assert with an explicit overrun check. If the transaction overruns the reservation, shutdown the filesystem immediately to prevent corruption. Add a new assert to xfs_trans_dup() to catch any callers that might induce this invalid state in the future. Signed-off-by:
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Matthew Wilcox authored
This is a simple rename, except that xa_ail becomes ail_head. Signed-off-by:
Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by:
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Dave Chinner authored
Noticed when looking at why cycling 600k inodes/s through the inode cache was taking a total of 8% cpu in memset() during inode initialisation. There is no need to zero the inode.i_data structure twice. This increases single threaded bulkstat throughput from ~200,000 inodes/s to ~220,000 inodes/s, so we save a substantial amount of CPU time per inode init by doing this. Signed-Off-By:
Jan Kara <jack@suse.cz> Reviewed-by:
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Dave Chinner authored
The AGFL size calculation is about to get more complex, so lets turn the macro into a function first and remove the macro. Signed-off-by:
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Darrick J. Wong authored
There's no point in allocating a transaction and locking the inode in preparation to clear cow blocks if there actually are any cow fork extents. Therefore, move the xfs_reflink_cancel_cow_range hunk to xfs_inactive and check the cow ifp first. This makes inode reclamation run faster. Signed-off-by:
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Darrick J. Wong authored
Yet another round of playing whack-a-mole with directory code that asserts on corrupt on-disk metadata when it really should be returning -EFSCORRUPTED instead of ASSERTing. Found by a xfs/391 crash while lastbit fuzzing of ltail.bestcount. Signed-off-by:
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Darrick J. Wong authored
In xfs_qm_dqalloc, we join the locked quota inode to the transaction we use to allocate blocks. If the allocation or mapping fails, we're not allowed to unlock the inode because the transaction code is in charge of unlocking it for us. Therefore, remove the iunlock call to avoid blowing asserts about unbalanced locking + mount hang. Found by corrupting the AGF and allocating space in the filesystem (quotacheck) immediately after mount. The upcoming agfl wrapping fixup test will trigger this scenario. Signed-off-by:
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Vratislav Bendel authored
Due to an inverted logic mistake in xfs_buftarg_isolate() the xfs_buffers with zero b_lru_ref will take another trip around LRU, while isolating buffers with non-zero b_lru_ref. Additionally those isolated buffers end up right back on the LRU once they are released, because b_lru_ref remains elevated. Fix that circuitous route by leaving them on the LRU as originally intended. Signed-off-by:
Vratislav Bendel <vbendel@redhat.com> Reviewed-by:
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Dave Chinner authored
xfs_trans_alloc() does GFP_KERNEL allocation, and we can call it while holding pages locked for writeback in the ->writepages path. The memory allocation is allowed to wait on pages under writeback, and so can wait on pages that are tagged as writeback by the caller. This affects both pre-IO submission and post-IO submission paths. Hence xfs_setsize_trans_alloc(), xfs_reflink_end_cow(), xfs_iomap_write_unwritten() and xfs_reflink_cancel_cow_range(). xfs_iomap_write_unwritten() already does the right thing, but the others don't. Fix them. Signed-Off-By:
Eric Sandeen <sandeen@redhat.com> Reviewed-by:
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