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xfs: write unmount record for ro mounts

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There are dueling comments in the xfs code about intent
for log writes when unmounting a readonly filesystem.

In xfs_mountfs, we see the intent:

/*
 * Now the log is fully replayed, we can transition to full read-only
 * mode for read-only mounts. This will sync all the metadata and clean
 * the log so that the recovery we just performed does not have to be
 * replayed again on the next mount.
 */

and it calls xfs_quiesce_attr(), but by the time we get to
xfs_log_unmount_write(), it returns early for a RDONLY mount:

 * Don't write out unmount record on read-only mounts.

Because of this, sequential ro mounts of a filesystem with
a dirty log will replay the log each time, which seems odd.

Fix this by writing an unmount record even for RO mounts, as long
as norecovery wasn't specified (don't write a clean log record
if a dirty log may still be there!) and the log device is
writable.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Eric Sandeen 2017-08-08 18:19:47 -07:00 committed by Darrick J. Wong
parent 6470812e22
commit 757a69ef6c
1 changed files with 5 additions and 2 deletions
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7
fs/xfs/xfs_log.c
View File

@ -812,11 +812,14 @@ xfs_log_unmount_write(xfs_mount_t *mp)
int error;
/*
* Don't write out unmount record on read-only mounts.
* Don't write out unmount record on norecovery mounts or ro devices.
* Or, if we are doing a forced umount (typically because of IO errors).
*/
if (mp->m_flags & XFS_MOUNT_RDONLY)
if (mp->m_flags & XFS_MOUNT_NORECOVERY ||
xfs_readonly_buftarg(log->l_mp->m_logdev_targp)) {
ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
return 0;
}
error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));