kernel/git/stable/linux.git/fs/xfs, branch linux-4.16.y

xfs: detect agfl count corruption and reset agfl

2018-06-05T09:46:10+00:00

commit a27ba2607e60312554cbcd43fc660b2c7f29dc9c upstream. 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 96f859d52bcb ("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 Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Reviewed-by Dave Chiluk Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: convert XFS_AGFL_SIZE to a helper function

2018-06-05T09:46:10+00:00

commit a78ee256c325ecfaec13cafc41b315bd4e1dd518 upstream. 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: Dave Chinner [darrick: forward port to newer kernel, simplify the helper] Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster Signed-off-by: Greg Kroah-Hartman

Force log to disk before reading the AGF during a fstrim

2018-05-30T06:17:21+00:00

[ Upstream commit 8c81dd46ef3c416b3b95e3020fb90dbd44e6140b ] Forcing the log to disk after reading the agf is wrong, we might be calling xfs_log_force with XFS_LOG_SYNC with a metadata lock held. This can cause a deadlock when racing a fstrim with a filesystem shutdown. The deadlock has been identified due a miscalculation bug in device-mapper dm-thin, which returns lack of space to its users earlier than the device itself really runs out of space, changing the device-mapper volume into an error state. The problem happened while filling the filesystem with a single file, triggering the bug in device-mapper, consequently causing an IO error and shutting down the filesystem. If such file is removed, and fstrim executed before the XFS finishes the shut down process, the fstrim process will end up holding the buffer lock, and going to sleep on the cil wait queue. At this point, the shut down process will try to wake up all the threads waiting on the cil wait queue, but for this, it will try to hold the same buffer log already held my the fstrim, locking up the filesystem. Signed-off-by: Carlos Maiolino Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

xfs: prevent creating negative-sized file via INSERT_RANGE

2018-05-09T07:53:07+00:00

commit 7d83fb14258b9961920cd86f0b921caaeb3ebe85 upstream. During the "insert range" fallocate operation, i_size grows by the specified 'len' bytes. XFS verifies that i_size + len < s_maxbytes, as it should. But this comparison is done using the signed 'loff_t', and 'i_size + len' can wrap around to a negative value, causing the check to incorrectly pass, resulting in an inode with "negative" i_size. This is possible on 64-bit platforms, where XFS sets s_maxbytes = LLONG_MAX. ext4 and f2fs don't run into this because they set a smaller s_maxbytes. Fix it by using subtraction instead. Reproducer: xfs_io -f file -c "truncate $(((1<<63)-1))" -c "finsert 0 4096" Fixes: a904b1ca5751 ("xfs: Add support FALLOC_FL_INSERT_RANGE for fallocate") Cc: # v4.1+ Originally-From: Eric Biggers Signed-off-by: Eric Biggers Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong [darrick: fix signed integer addition overflow too] Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: don't block on the ilock for RWF_NOWAIT

2018-03-01T22:12:45+00:00

Fix xfs_file_iomap_begin to trylock the ilock if IOMAP_NOWAIT is passed, so that we don't block io_submit callers. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: don't start out with the exclusive ilock for direct I/O

2018-03-01T22:12:12+00:00

There is no reason to take the ilock exclusively at the start of xfs_file_iomap_begin for direct I/O, given that it will be demoted just before calling xfs_iomap_write_direct anyway. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: don't allocate COW blocks for zeroing holes or unwritten extents

2018-03-01T22:10:31+00:00

The iomap zeroing interface is smart enough to skip zeroing holes or unwritten extents. Don't subvert this logic for reflink files. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: fix potential memory leak in mount option parsing

2018-02-26T18:02:13+00:00

When specifying string type mount option (e.g., logdev) several times in a mount, current option parsing may cause memory leak. Hence, call kfree for previous one in this case. Signed-off-by: Chengguang Xu Reviewed-by: Eric Sandeen Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: reserve blocks for refcount / rmap log item recovery

2018-02-22T22:41:25+00:00

During log recovery, the per-AG reservations aren't yet set up, so log recovery has to reserve enough blocks to handle all possible btree splits. Reported-by: Dave Chinner Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner

xfs: use memset to initialize xfs_scrub_agfl_info

2018-02-22T22:41:25+00:00

Apparently different gcc versions have competing and incompatible notions of how to initialize at declaration, so just give up and fall back to the time-tested memset(). Signed-off-by: Eric Sandeen Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong