1. 13 12月, 2020 6 次提交
  2. 10 12月, 2020 29 次提交
  3. 09 12月, 2020 1 次提交
  4. 20 11月, 2020 2 次提交
    • D
      xfs: revert "xfs: fix rmap key and record comparison functions" · eb840907
      Darrick J. Wong 提交于
      This reverts commit 6ff646b2.
      
      Your maintainer committed a major braino in the rmap code by adding the
      attr fork, bmbt, and unwritten extent usage bits into rmap record key
      comparisons.  While XFS uses the usage bits *in the rmap records* for
      cross-referencing metadata in xfs_scrub and xfs_repair, it only needs
      the owner and offset information to distinguish between reverse mappings
      of the same physical extent into the data fork of a file at multiple
      offsets.  The other bits are not important for key comparisons for index
      lookups, and never have been.
      
      Eric Sandeen reports that this causes regressions in generic/299, so
      undo this patch before it does more damage.
      Reported-by: NEric Sandeen <sandeen@sandeen.net>
      Fixes: 6ff646b2 ("xfs: fix rmap key and record comparison functions")
      Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      Reviewed-by: NEric Sandeen <sandeen@redhat.com>
      eb840907
    • D
      xfs: don't allow NOWAIT DIO across extent boundaries · 883a790a
      Dave Chinner 提交于
      Jens has reported a situation where partial direct IOs can be issued
      and completed yet still return -EAGAIN. We don't want this to report
      a short IO as we want XFS to complete user DIO entirely or not at
      all.
      
      This partial IO situation can occur on a write IO that is split
      across an allocated extent and a hole, and the second mapping is
      returning EAGAIN because allocation would be required.
      
      The trivial reproducer:
      
      $ sudo xfs_io -fdt -c "pwrite 0 4k" -c "pwrite -V 1 -b 8k -N 0 8k" /mnt/scr/foo
      wrote 4096/4096 bytes at offset 0
      4 KiB, 1 ops; 0.0001 sec (27.509 MiB/sec and 7042.2535 ops/sec)
      pwrite: Resource temporarily unavailable
      $
      
      The pwritev2(0, 8kB, RWF_NOWAIT) call returns EAGAIN having done
      the first 4kB write:
      
       xfs_file_direct_write: dev 259:1 ino 0x83 size 0x1000 offset 0x0 count 0x2000
       iomap_apply:          dev 259:1 ino 0x83 pos 0 length 8192 flags WRITE|DIRECT|NOWAIT (0x31) ops xfs_direct_write_iomap_ops caller iomap_dio_rw actor iomap_dio_actor
       xfs_ilock_nowait:     dev 259:1 ino 0x83 flags ILOCK_SHARED caller xfs_ilock_for_iomap
       xfs_iunlock:          dev 259:1 ino 0x83 flags ILOCK_SHARED caller xfs_direct_write_iomap_begin
       xfs_iomap_found:      dev 259:1 ino 0x83 size 0x1000 offset 0x0 count 8192 fork data startoff 0x0 startblock 24 blockcount 0x1
       iomap_apply_dstmap:   dev 259:1 ino 0x83 bdev 259:1 addr 102400 offset 0 length 4096 type MAPPED flags DIRTY
      
      Here the first iomap loop has mapped the first 4kB of the file and
      issued the IO, and we enter the second iomap_apply loop:
      
       iomap_apply: dev 259:1 ino 0x83 pos 4096 length 4096 flags WRITE|DIRECT|NOWAIT (0x31) ops xfs_direct_write_iomap_ops caller iomap_dio_rw actor iomap_dio_actor
       xfs_ilock_nowait:     dev 259:1 ino 0x83 flags ILOCK_SHARED caller xfs_ilock_for_iomap
       xfs_iunlock:          dev 259:1 ino 0x83 flags ILOCK_SHARED caller xfs_direct_write_iomap_begin
      
      And we exit with -EAGAIN out because we hit the allocate case trying
      to make the second 4kB block.
      
      Then IO completes on the first 4kB and the original IO context
      completes and unlocks the inode, returning -EAGAIN to userspace:
      
       xfs_end_io_direct_write: dev 259:1 ino 0x83 isize 0x1000 disize 0x1000 offset 0x0 count 4096
       xfs_iunlock:          dev 259:1 ino 0x83 flags IOLOCK_SHARED caller xfs_file_dio_aio_write
      
      There are other vectors to the same problem when we re-enter the
      mapping code if we have to make multiple mappinfs under NOWAIT
      conditions. e.g. failing trylocks, COW extents being found,
      allocation being required, and so on.
      
      Avoid all these potential problems by only allowing IOMAP_NOWAIT IO
      to go ahead if the mapping we retrieve for the IO spans an entire
      allocated extent. This avoids the possibility of subsequent mappings
      to complete the IO from triggering NOWAIT semantics by any means as
      NOWAIT IO will now only enter the mapping code once per NOWAIT IO.
      Reported-and-tested-by: NJens Axboe <axboe@kernel.dk>
      Signed-off-by: NDave Chinner <dchinner@redhat.com>
      Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
      Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      883a790a
  5. 19 11月, 2020 2 次提交