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Date:   Mon, 18 Sep 2017 11:12:00 +0200
From:   Greg Kroah-Hartman <>
Cc:     Greg Kroah-Hartman <>,
        Eric Sandeen <>,
        Brian Foster <>,
        Christoph Hellwig <>,
        "Darrick J. Wong" <>
Subject: [PATCH 4.9 51/78] xfs: write unmount record for ro mounts

4.9-stable review patch.  If anyone has any objections, please let me know.


From: Eric Sandeen <>

commit 757a69ef6cf2bf839bd4088e5609ddddd663b0c4 upstream.

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

Signed-off-by: Eric Sandeen <>
Reviewed-by: Brian Foster <>
Reviewed-by: Christoph Hellwig <>
Reviewed-by: Darrick J. Wong <>
Signed-off-by: Darrick J. Wong <>
Signed-off-by: Greg Kroah-Hartman <>
 fs/xfs/xfs_log.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -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)));

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