[XFS] Fix dbflush panic in xfs_qm_sync.

The recent behaviour layer removal dropped the check for quotas that have
been requested at mount time but have subsequently been turned off. This
results in a panic when accessing m_quotainfo which has been freed.

This patch adds the check originally made by xfs_qm_syncall() to
xfs_qm_sync().

SGI-PV: 969769
SGI-Modid: xfs-linux-melb:xfs-kern:29908a

Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

diff --git a/fs/xfs/quota/xfs_qm.c b/fs/xfs/quota/xfs_qm.c
index b5f9128..d488645 100644 (file)
--- a/fs/xfs/quota/xfs_qm.c
+++ b/fs/xfs/quota/xfs_qm.c
@@ -1008,6 +1008,9 @@ xfs_qm_sync(
        boolean_t       nowait;
        int             error;
 
+       if (! XFS_IS_QUOTA_ON(mp))
+               return 0;
+
        restarts = 0;
        /*
         * We won't block unless we are asked to.