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author | Brian Foster <bfoster@redhat.com> | 2016-02-08 15:00:02 +1100 |
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committer | Dave Chinner <david@fromorbit.com> | 2016-02-08 15:00:02 +1100 |
commit | 60630fe66ed28d43379382645ed349f7d3457330 (patch) | |
tree | d9926d31bf5a59c51c8b906267b73ac803fd9faf /fs/autofs4/Makefile | |
parent | 244efeafb65ad4d98cd0c9463631e3931d813a6e (diff) | |
download | linux-60630fe66ed28d43379382645ed349f7d3457330.tar.bz2 |
xfs: clean up unwritten buffers on write failure
The xfs_vm_write_failed() handler is currently responsible for cleaning
up any delalloc blocks over the range of a failed write beyond EOF.
Failure to do so results in warning messages and other inconsistencies
between buffer and extent state. The ->releasepage() handler currently
warns in the event of a page being released with either unwritten or
delalloc buffers, as neither is ever expected by the time a page is
released.
As has been reproduced by generic/083 on a -bsize=1k fs, it is currently
possible to trigger the ->releasepage() warning for a page with
unwritten buffers when a filesystem is near ENOSPC. This is reproduced
by the following sequence:
$ mkfs.xfs -f -b size=1k -d size=100m <dev>
$ mount <dev> /mnt/
$
$ xfs_io -fc "falloc -k 0 1k" /mnt/file
$ dd if=/dev/zero of=/mnt/enospc conv=notrunc oflag=append
$
$ xfs_io -c "pwrite 512 1k" /mnt/file
$ xfs_io -d -c "pwrite 16k 1k" /mnt/file
The first pwrite command attempts a block unaligned write across an
unwritten block and a hole. The delalloc for the hole fails with ENOSPC
and the subsequent error handling does not clean up the unwritten buffer
that was instantiated during the first ->get_block() call.
The second pwrite triggers a warning as part of the inode mapping
invalidation that occurs prior to direct I/O. The releasepage() handler
detects the unwritten buffer at this time, warns and prevents the
release of the page.
To deal with this problem, update xfs_vm_write_failed() to clean up
unwritten as well as delalloc buffers that are beyond EOF and within the
range of the failed write.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/autofs4/Makefile')
0 files changed, 0 insertions, 0 deletions