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2024-11-05xfs: split write fault handling out of __xfs_filemap_faultChristoph Hellwig
Only two of the callers of __xfs_filemap_fault every handle read faults. Split the write_fault handling out of __xfs_filemap_fault so that all callers call that directly either conditionally or unconditionally and only leave the read fault handling in __xfs_filemap_fault. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-11-05xfs: split the page fault trace eventChristoph Hellwig
Split the xfs_filemap_fault trace event into separate ones for read and write faults and move them into the applicable locations. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-11-05xfs: sb_spino_align is not verifiedDave Chinner
It's just read in from the superblock and used without doing any validity checks at all on the value. Fixes: fb4f2b4e5a82 ("xfs: add sparse inode chunk alignment superblock field") Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-11-05xfs: simplify sector number calculation in xfs_zero_extentChristoph Hellwig
xfs_zero_extent does some really odd gymnstics to calculate the block layer sectors numbers passed to blkdev_issue_zeroout. This is because it used to call sb_issue_zeroout and the calculations in that helper got open coded here in the rather misleadingly named commit 3dc29161070a ("dax: use sb_issue_zerout instead of calling dax_clear_sectors"). Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-11-05xfs: remove the redundant xfs_alloc_log_agfLong Li
There are two invocations of xfs_alloc_log_agf in xfs_alloc_put_freelist. The AGF does not change between the two calls. Although this does not pose any practical problems, it seems like a small mistake. Therefore, fix it by removing the first xfs_alloc_log_agf invocation. Signed-off-by: Long Li <leo.lilong@huawei.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-11-04xfs: Support setting FMODE_CAN_ATOMIC_WRITEJohn Garry
Set FMODE_CAN_ATOMIC_WRITE flag if we can atomic write for that inode. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: John Garry <john.g.garry@oracle.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> #On ppc64
2024-11-04xfs: Validate atomic writesJohn Garry
Validate that an atomic write adheres to length/offset rules. Currently we can only write a single FS block. For an IOCB with IOCB_ATOMIC set to get as far as xfs_file_write_iter(), FMODE_CAN_ATOMIC_WRITE will need to be set for the file; for this, ATOMICWRITES flags would also need to be set for the inode. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2024-11-04xfs: Support atomic write for statxJohn Garry
Support providing info on atomic write unit min and max for an inode. For simplicity, currently we limit the min at the FS block size. As for max, we limit also at FS block size, as there is no current method to guarantee extent alignment or granularity for regular files. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2024-11-03fdget(), more trivial conversionsAl Viro
all failure exits prior to fdget() leave the scope, all matching fdput() are immediately followed by leaving the scope. [xfs_ioc_commit_range() chunk moved here as well] Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03simplify xfs_find_handle() a bitAl Viro
XFS_IOC_FD_TO_HANDLE can grab a reference to copied ->f_path and let the file go; results in simpler control flow - cleanup is the same for both "by descriptor" and "by pathname" cases. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-02Merge tag 'xfs-6.12-fixes-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull xfs fixes from Carlos Maiolino: - fix a sysbot reported crash on filestreams - Reduce cpu time spent searching for extents in a very fragmented FS - Check for delayed allocations before setting extsize * tag 'xfs-6.12-fixes-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: streamline xfs_filestream_pick_ag xfs: fix finding a last resort AG in xfs_filestream_pick_ag xfs: Reduce unnecessary searches when searching for the best extents xfs: Check for delayed allocations before setting extsize
2024-11-01Merge tag 'vfs-6.12-rc6.iomap' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull iomap fixes from Christian Brauner: "Fixes for iomap to prevent data corruption bugs in the fallocate unshare range implementation of fsdax and a small cleanup to turn iomap_want_unshare_iter() into an inline function" * tag 'vfs-6.12-rc6.iomap' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: iomap: turn iomap_want_unshare_iter into an inline function fsdax: dax_unshare_iter needs to copy entire blocks fsdax: remove zeroing code from dax_unshare_iter iomap: share iomap_unshare_iter predicate code with fsdax xfs: don't allocate COW extents when unsharing a hole
2024-10-30xfs: streamline xfs_filestream_pick_agChristoph Hellwig
Directly return the error from xfs_bmap_longest_free_extent instead of breaking from the loop and handling it there, and use a done label to directly jump to the exist when we found a suitable perag structure to reduce the indentation level and pag/max_pag check complexity in the tail of the function. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-30xfs: fix finding a last resort AG in xfs_filestream_pick_agChristoph Hellwig
When the main loop in xfs_filestream_pick_ag fails to find a suitable AG it tries to just pick the online AG. But the loop for that uses args->pag as loop iterator while the later code expects pag to be set. Fix this by reusing the max_pag case for this last resort, and also add a check for impossible case of no AG just to make sure that the uninitialized pag doesn't even escape in theory. Reported-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com Fixes: f8f1ed1ab3baba ("xfs: return a referenced perag from filestreams allocator") Cc: <stable@vger.kernel.org> # v6.3 Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-30xfs: Reduce unnecessary searches when searching for the best extentsChi Zhiling
Recently, we found that the CPU spent a lot of time in xfs_alloc_ag_vextent_size when the filesystem has millions of fragmented spaces. The reason is that we conducted much extra searching for extents that could not yield a better result, and these searches would cost a lot of time when there were millions of extents to search through. Even if we get the same result length, we don't switch our choice to the new one, so we can definitely terminate the search early. Since the result length cannot exceed the found length, when the found length equals the best result length we already have, we can conclude the search. We did a test in that filesystem: [root@localhost ~]# xfs_db -c freesp /dev/vdb from to extents blocks pct 1 1 215 215 0.01 2 3 994476 1988952 99.99 Before this patch: 0) | xfs_alloc_ag_vextent_size [xfs]() { 0) * 15597.94 us | } After this patch: 0) | xfs_alloc_ag_vextent_size [xfs]() { 0) 19.176 us | } Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-30xfs: Check for delayed allocations before setting extsizeOjaswin Mujoo
Extsize should only be allowed to be set on files with no data in it. For this, we check if the files have extents but miss to check if delayed extents are present. This patch adds that check. While we are at it, also refactor this check into a helper since it's used in some other places as well like xfs_inactive() or xfs_ioctl_setattr_xflags() **Without the patch (SUCCEEDS)** $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536' wrote 1024/1024 bytes at offset 0 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec) **With the patch (FAILS as expected)** $ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536' wrote 1024/1024 bytes at offset 0 1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec) xfs_io: FS_IOC_FSSETXATTR testfile: Invalid argument Fixes: e94af02a9cd7 ("[XFS] fix old xfs_setattr mis-merge from irix; mostly harmless esp if not using xfs rt") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: update the pag for the last AG at recovery timeChristoph Hellwig
Currently log recovery never updates the in-core perag values for the last allocation group when they were grown by growfs. This leads to btree record validation failures for the alloc, ialloc or finotbt trees if a transaction references this new space. Found by Brian's new growfs recovery stress test. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: don't use __GFP_RETRY_MAYFAIL in xfs_initialize_peragChristoph Hellwig
__GFP_RETRY_MAYFAIL increases the likelyhood of allocations to fail, which isn't really helpful during log recovery. Remove the flag and stick to the default GFP_KERNEL policies. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: error out when a superblock buffer update reduces the agcountChristoph Hellwig
XFS currently does not support reducing the agcount, so error out if a logged sb buffer tries to shrink the agcount. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: update the file system geometry after recoverying superblock buffersChristoph Hellwig
Primary superblock buffers that change the file system geometry after a growfs operation can affect the operation of later CIL checkpoints that make use of the newly added space and allocation groups. Apply the changes to the in-memory structures as part of recovery pass 2, to ensure recovery works fine for such cases. In the future we should apply the logic to other updates such as features bits as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: merge the perag freeing helpersChristoph Hellwig
There is no good reason to have two different routines for freeing perag structures for the unmount and error cases. Add two arguments to specify the range of AGs to free to xfs_free_perag, and use that to replace xfs_free_unused_perag_range. The addition RCU grace period for the error case is harmless, and the extra check for the AG to actually exist is not required now that the callers pass the exact known allocated range. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: pass the exact range to initialize to xfs_initialize_peragChristoph Hellwig
Currently only the new agcount is passed to xfs_initialize_perag, which requires lookups of existing AGs to skip them and complicates error handling. Also pass the previous agcount so that the range that xfs_initialize_perag operates on is exactly defined. That way the extra lookups can be avoided, and error handling can clean up the exact range from the old count to the last added perag structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-22xfs: don't fail repairs on metadata files with no attr forkDarrick J. Wong
Fix a minor bug where we fail repairs on metadata files that do not have attr forks because xrep_metadata_inode_subtype doesn't filter ENOENT. Cc: stable@vger.kernel.org # v6.8 Fixes: 5a8e07e799721b ("xfs: repair the inode core and forks of a metadata inode") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: punch delalloc extents from the COW fork for COW writesChristoph Hellwig
When ->iomap_end is called on a short write to the COW fork it needs to punch stale delalloc data from the COW fork and not the data fork. Ensure that IOMAP_F_NEW is set for new COW fork allocations in xfs_buffered_write_iomap_begin, and then use the IOMAP_F_SHARED flag in xfs_buffered_write_delalloc_punch to decide which fork to punch. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: set IOMAP_F_SHARED for all COW fork allocationsChristoph Hellwig
Change to always set xfs_buffered_write_iomap_begin for COW fork allocations even if they don't overlap existing data fork extents, which will allow the iomap_end callback to detect if it has to punch stale delalloc blocks from the COW fork instead of the data fork. It also means we sample the sequence counter for both the data and the COW fork when writing to the COW fork, which ensures we properly revalidate when only COW fork changes happens. This is essentially a revert of commit 72a048c1056a ("xfs: only set IOMAP_F_SHARED when providing a srcmap to a write"). This is fine because the problem that the commit fixed has now been dealt with in iomap by only looking at the actual srcmap and not the fallback to the write iomap. Note that the direct I/O path was never changed and has always set IOMAP_F_SHARED for all COW fork allocations. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: share more code in xfs_buffered_write_iomap_beginChristoph Hellwig
Introduce a local iomap_flags variable so that the code allocating new delalloc blocks in the data fork can fall through to the found_imap label and reuse the code to unlock and fill the iomap. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: support the COW fork in xfs_bmap_punch_delalloc_rangeChristoph Hellwig
xfs_buffered_write_iomap_begin can also create delallocate reservations that need cleaning up, prepare for that by adding support for the COW fork in xfs_bmap_punch_delalloc_range. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: IOMAP_ZERO and IOMAP_UNSHARE already hold invalidate_lockChristoph Hellwig
All XFS callers of iomap_zero_range and iomap_file_unshare already hold invalidate_lock, so we can't take it again in iomap_file_buffered_write_punch_delalloc. Use the passed in flags argument to detect if we're called from a zero or unshare operation and don't take the lock again in this case. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: take XFS_MMAPLOCK_EXCL xfs_file_write_zero_eofChristoph Hellwig
xfs_file_write_zero_eof is the only caller of xfs_zero_range that does not take XFS_MMAPLOCK_EXCL (aka the invalidate lock). Currently that is actually the right thing, as an error in the iomap zeroing code will also take the invalidate_lock to clean up, but to fix that deadlock we need a consistent locking pattern first. The only extra thing that XFS_MMAPLOCK_EXCL will lock out are read pagefaults, which isn't really needed here, but also not actively harmful. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15xfs: factor out a xfs_file_write_zero_eof helperChristoph Hellwig
Split a helper from xfs_file_write_checks that just deal with the post-EOF zeroing to keep the code readable. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15iomap: move locking out of iomap_write_delalloc_releaseChristoph Hellwig
XFS (which currently is the only user of iomap_write_delalloc_release) already holds invalidate_lock for most zeroing operations. To be able to avoid a deadlock it needs to stop taking the lock, but doing so in iomap would leak XFS locking details into iomap. To avoid this require the caller to hold invalidate_lock when calling iomap_write_delalloc_release instead of taking it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-15iomap: remove iomap_file_buffered_write_punch_delallocChristoph Hellwig
Currently iomap_file_buffered_write_punch_delalloc can be called from XFS either with the invalidate lock held or not. To fix this while keeping the locking in the file system and not the iomap library code we'll need to life the locking up into the file system. To prepare for that, open code iomap_file_buffered_write_punch_delalloc in the only caller, and instead export iomap_write_delalloc_release. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-11xfs: fix integer overflow in xrep_bmapDarrick J. Wong
The variable declaration in this function predates the merge of the nrext64 (aka 64-bit extent counters) feature, which means that the variable declaration type is insufficient to avoid an integer overflow. Fix that by redeclaring the variable to be xfs_extnum_t. Coverity-id: 1630958 Fixes: 8f71bede8efd ("xfs: repair inode fork block mapping data structures") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-10Merge patch series "timekeeping/fs: multigrain timestamp redux"Christian Brauner
Jeff Layton <jlayton@kernel.org> says: The VFS has always used coarse-grained timestamps when updating the ctime and mtime after a change. This has the benefit of allowing filesystems to optimize away a lot metadata updates, down to around 1 per jiffy, even when a file is under heavy writes. Unfortunately, this has always been an issue when we're exporting via NFSv3, which relies on timestamps to validate caches. A lot of changes can happen in a jiffy, so timestamps aren't sufficient to help the client decide when to invalidate the cache. Even with NFSv4, a lot of exported filesystems don't properly support a change attribute and are subject to the same problems with timestamp granularity. Other applications have similar issues with timestamps (e.g backup applications). If we were to always use fine-grained timestamps, that would improve the situation, but that becomes rather expensive, as the underlying filesystem would have to log a lot more metadata updates. What we need is a way to only use fine-grained timestamps when they are being actively queried. Use the (unused) top bit in inode->i_ctime_nsec as a flag that indicates whether the current timestamps have been queried via stat() or the like. When it's set, we allow the kernel to use a fine-grained timestamp iff it's necessary to make the ctime show a different value. This solves the problem of being able to distinguish the timestamp between updates, but introduces a new problem: it's now possible for a file being changed to get a fine-grained timestamp. A file that is altered just a bit later can then get a coarse-grained one that appears older than the earlier fine-grained time. This violates timestamp ordering guarantees. To remedy this, keep a global monotonic atomic64_t value that acts as a timestamp floor. When we go to stamp a file, we first get the latter of the current floor value and the current coarse-grained time. If the inode ctime hasn't been queried then we just attempt to stamp it with that value. If it has been queried, then first see whether the current coarse time is later than the existing ctime. If it is, then we accept that value. If it isn't, then we get a fine-grained time and try to swap that into the global floor. Whether that succeeds or fails, we take the resulting floor time, convert it to realtime and try to swap that into the ctime. We take the result of the ctime swap whether it succeeds or fails, since either is just as valid. Filesystems can opt into this by setting the FS_MGTIME fstype flag. Others should be unaffected (other than being subject to the same floor value as multigrain filesystems). * patches from https://lore.kernel.org/r/20241002-mgtime-v10-0-d1c4717f5284@kernel.org: tmpfs: add support for multigrain timestamps btrfs: convert to multigrain timestamps ext4: switch to multigrain timestamps xfs: switch to multigrain timestamps Documentation: add a new file documenting multigrain timestamps fs: add percpu counters for significant multigrain timestamp events fs: tracepoints around multigrain timestamp events fs: handle delegated timestamps in setattr_copy_mgtime fs: have setattr_copy handle multigrain timestamps appropriately fs: add infrastructure for multigrain timestamps Link: https://lore.kernel.org/r/20241002-mgtime-v10-0-d1c4717f5284@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-10xfs: switch to multigrain timestampsJeff Layton
Enable multigrain timestamps, which should ensure that there is an apparent change to the timestamp whenever it has been written after being actively observed via getattr. Also, anytime the mtime changes, the ctime must also change, and those are now the only two options for xfs_trans_ichgtime. Have that function unconditionally bump the ctime, and ASSERT that XFS_ICHGTIME_CHG is always set. Finally, stop setting STATX_CHANGE_COOKIE in getattr, since the ctime should give us better semantics now. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20241002-mgtime-v10-9-d1c4717f5284@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-09xfs: fix a typoAndrew Kreimer
Fix a typo in comments. Signed-off-by: Andrew Kreimer <algonell@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-09xfs: don't free cowblocks from under dirty pagecache on unshareBrian Foster
fallocate unshare mode explicitly breaks extent sharing. When a command completes, it checks the data fork for any remaining shared extents to determine whether the reflink inode flag and COW fork preallocation can be removed. This logic doesn't consider in-core pagecache and I/O state, however, which means we can unsafely remove COW fork blocks that are still needed under certain conditions. For example, consider the following command sequence: xfs_io -fc "pwrite 0 1k" -c "reflink <file> 0 256k 1k" \ -c "pwrite 0 32k" -c "funshare 0 1k" <file> This allocates a data block at offset 0, shares it, and then overwrites it with a larger buffered write. The overwrite triggers COW fork preallocation, 32 blocks by default, which maps the entire 32k write to delalloc in the COW fork. All but the shared block at offset 0 remains hole mapped in the data fork. The unshare command redirties and flushes the folio at offset 0, removing the only shared extent from the inode. Since the inode no longer maps shared extents, unshare purges the COW fork before the remaining 28k may have written back. This leaves dirty pagecache backed by holes, which writeback quietly skips, thus leaving clean, non-zeroed pagecache over holes in the file. To verify, fiemap shows holes in the first 32k of the file and reads return different data across a remount: $ xfs_io -c "fiemap -v" <file> <file>: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS ... 1: [8..511]: hole 504 ... $ xfs_io -c "pread -v 4k 8" <file> 00001000: cd cd cd cd cd cd cd cd ........ $ umount <mnt>; mount <dev> <mnt> $ xfs_io -c "pread -v 4k 8" <file> 00001000: 00 00 00 00 00 00 00 00 ........ To avoid this problem, make unshare follow the same rules used for background cowblock scanning and never purge the COW fork for inodes with dirty pagecache or in-flight I/O. Fixes: 46afb0628b86347 ("xfs: only flush the unshared range in xfs_reflink_unshare") Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-08Merge patch series "fsdax/xfs: unshare range fixes for 6.12"Christian Brauner
Darrick J. Wong <djwong@kernel.org> says: This patchset fixes multiple data corruption bugs in the fallocate unshare range implementation for fsdax. * patches from https://lore.kernel.org/r/172796813251.1131942.12184885574609980777.stgit@frogsfrogsfrogs: fsdax: dax_unshare_iter needs to copy entire blocks fsdax: remove zeroing code from dax_unshare_iter iomap: share iomap_unshare_iter predicate code with fsdax xfs: don't allocate COW extents when unsharing a hole Link: https://lore.kernel.org/r/172796813251.1131942.12184885574609980777.stgit@frogsfrogsfrogs Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-07xfs: don't allocate COW extents when unsharing a holeDarrick J. Wong
It doesn't make sense to allocate a COW extent when unsharing a hole because holes cannot be shared. Fixes: 1f1397b7218d7 ("xfs: don't allocate into the data fork for an unshare request") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/172796813277.1131942.5486112889531210260.stgit@frogsfrogsfrogs Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-07xfs: skip background cowblock trims on inodes open for writeBrian Foster
The background blockgc scanner runs on a 5m interval by default and trims preallocation (post-eof and cow fork) from inodes that are otherwise idle. Idle effectively means that iolock can be acquired without blocking and that the inode has no dirty pagecache or I/O in flight. This simple mechanism and heuristic has worked fairly well for post-eof speculative preallocations. Support for reflink and COW fork preallocations came sometime later and plugged into the same mechanism, with similar heuristics. Some recent testing has shown that COW fork preallocation may be notably more sensitive to blockgc processing than post-eof preallocation, however. For example, consider an 8GB reflinked file with a COW extent size hint of 1MB. A worst case fully randomized overwrite of this file results in ~8k extents of an average size of ~1MB. If the same workload is interrupted a couple times for blockgc processing (assuming the file goes idle), the resulting extent count explodes to over 100k extents with an average size <100kB. This is significantly worse than ideal and essentially defeats the COW extent size hint mechanism. While this particular test is instrumented, it reflects a fairly reasonable pattern in practice where random I/Os might spread out over a large period of time with varying periods of (in)activity. For example, consider a cloned disk image file for a VM or container with long uptime and variable and bursty usage. A background blockgc scan that races and processes the image file when it happens to be clean and idle can have a significant effect on the future fragmentation level of the file, even when still in use. To help combat this, update the heuristic to skip cowblocks inodes that are currently opened for write access during non-sync blockgc scans. This allows COW fork preallocations to persist for as long as possible unless otherwise needed for functional purposes (i.e. a sync scan), the file is idle and closed, or the inode is being evicted from cache. While here, update the comments to help distinguish performance oriented heuristics from the logic that exists to maintain functional correctness. Suggested-by: Darrick Wong <djwong@kernel.org> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: support lowmode allocations in xfs_bmap_exact_minlen_extent_allocChristoph Hellwig
Currently the debug-only xfs_bmap_exact_minlen_extent_alloc allocation variant fails to drop into the lowmode last resort allocator, and thus can sometimes fail allocations for which the caller has a transaction block reservation. Fix this by using xfs_bmap_btalloc_low_space to do the actual allocation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: call xfs_bmap_exact_minlen_extent_alloc from xfs_bmap_btallocChristoph Hellwig
xfs_bmap_exact_minlen_extent_alloc duplicates the args setup in xfs_bmap_btalloc. Switch to call it from xfs_bmap_btalloc after doing the basic setup. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: don't ifdef around the exact minlen allocationsChristoph Hellwig
Exact minlen allocations only exist as an error injection tool for debug builds. Currently this is implemented using ifdefs, which means the code isn't even compiled for non-XFS_DEBUG builds. Enhance the compile test coverage by always building the code and use the compilers' dead code elimination to remove it from the generated binary instead. The only downside is that the alloc_minlen_only field is unconditionally added to struct xfs_alloc_args now, but by moving it around and packing it tightly this doesn't actually increase the size of the structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: fold xfs_bmap_alloc_userdata into xfs_bmapi_allocateChristoph Hellwig
Userdata and metadata allocations end up in the same allocation helpers. Remove the separate xfs_bmap_alloc_userdata function to make this more clear. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: distinguish extra split from real ENOSPC from xfs_attr_node_try_addnameChristoph Hellwig
Just like xfs_attr3_leaf_split, xfs_attr_node_try_addname can return -ENOSPC both for an actual failure to allocate a disk block, but also to signal the caller to convert the format of the attr fork. Use magic 1 to ask for the conversion here as well. Note that unlike the similar issue in xfs_attr3_leaf_split, this one was only found by code review. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: distinguish extra split from real ENOSPC from xfs_attr3_leaf_splitChristoph Hellwig
xfs_attr3_leaf_split propagates the need for an extra btree split as -ENOSPC to it's only caller, but the same return value can also be returned from xfs_da_grow_inode when it fails to find free space. Distinguish the two cases by returning 1 for the extra split case instead of overloading -ENOSPC. This can be triggered relatively easily with the pending realtime group support and a file system with a lot of small zones that use metadata space on the main device. In this case every about 5-10th run of xfs/538 runs into the following assert: ASSERT(oldblk->magic == XFS_ATTR_LEAF_MAGIC); in xfs_attr3_leaf_split caused by an allocation failure. Note that the allocation failure is caused by another bug that will be fixed subsequently, but this commit at least sorts out the error handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: return bool from xfs_attr3_leaf_addChristoph Hellwig
xfs_attr3_leaf_add only has two potential return values, indicating if the entry could be added or not. Replace the errno return with a bool so that ENOSPC from it can't easily be confused with a real ENOSPC. Remove the return value from the xfs_attr3_leaf_add_work helper entirely, as it always return 0. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: merge xfs_attr_leaf_try_add into xfs_attr_leaf_addnameChristoph Hellwig
xfs_attr_leaf_try_add is only called by xfs_attr_leaf_addname, and merging the two will simplify a following error handling fix. To facilitate this move the remote block state save/restore helpers up in the file so that they don't need forward declarations now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: Use try_cmpxchg() in xlog_cil_insert_pcp_aggregate()Uros Bizjak
Use !try_cmpxchg instead of cmpxchg (*ptr, old, new) != old in xlog_cil_insert_pcp_aggregate(). x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg. Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg fails. There is no need to re-read the value in the loop. Note that the value from *ptr should be read using READ_ONCE to prevent the compiler from merging, refetching or reordering the read. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Cc: Chandan Babu R <chandan.babu@oracle.com> Cc: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2024-10-07xfs: scrub: convert comma to semicolonYan Zhen
Replace a comma between expression statements by a semicolon. Signed-off-by: Yan Zhen <yanzhen@vivo.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>