[PATCH 4.9 52/78] xfs: toggle readonly state around xfs_log_mount_finish

From: Greg Kroah-Hartman
Date: Mon Sep 18 2017 - 05:16:58 EST


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

------------------

From: Eric Sandeen <sandeen@xxxxxxxxxxx>

commit 6f4a1eefdd0ad4561543270a7fceadabcca075dd upstream.

When we do log recovery on a readonly mount, unlinked inode
processing does not happen due to the readonly checks in
xfs_inactive(), which are trying to prevent any I/O on a
readonly mount.

This is misguided - we do I/O on readonly mounts all the time,
for consistency; for example, log recovery. So do the same
RDONLY flag twiddling around xfs_log_mount_finish() as we
do around xfs_log_mount(), for the same reason.

This all cries out for a big rework but for now this is a
simple fix to an obvious problem.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/xfs_log.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -743,10 +743,14 @@ xfs_log_mount_finish(
struct xfs_mount *mp)
{
int error = 0;
+ bool readonly = (mp->m_flags & XFS_MOUNT_RDONLY);

if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
return 0;
+ } else if (readonly) {
+ /* Allow unlinked processing to proceed */
+ mp->m_flags &= ~XFS_MOUNT_RDONLY;
}

/*
@@ -764,6 +768,9 @@ xfs_log_mount_finish(
xfs_log_work_queue(mp);
mp->m_super->s_flags &= ~MS_ACTIVE;

+ if (readonly)
+ mp->m_flags |= XFS_MOUNT_RDONLY;
+
return error;
}