xfs: fix inode validity check in xfs_iflush_cluster

Some careless idiot(*) wrote crap code in commit 1a3e8f3 ("xfs:
convert inode cache lookups to use RCU locking") back in late 2010,
and so xfs_iflush_cluster checks the wrong inode for whether it is
still valid under RCU protection. Fix it to lock and check the
correct inode.

(*) Careless-idiot: Dave Chinner <dchinner@redhat.com>

cc: <stable@vger.kernel.org> # 3.10.x-
Discovered-by: Brain Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 696936cad0fa..a955b0212453 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3205,13 +3205,13 @@ xfs_iflush_cluster(
                  * We need to check under the i_flags_lock for a valid inode
                  * here. Skip it if it is not valid or the wrong inode.
                  */
-                spin_lock(&ip->i_flags_lock);
-                if (!ip->i_ino ||
+                spin_lock(&iq->i_flags_lock);
+                if (!iq->i_ino ||
                     (XFS_INO_TO_AGINO(mp, iq->i_ino) & mask) != first_index) {
-                        spin_unlock(&ip->i_flags_lock);
+                        spin_unlock(&iq->i_flags_lock);
                         continue;
                 }
-                spin_unlock(&ip->i_flags_lock);
+                spin_unlock(&iq->i_flags_lock);
 
                 /*
                  * Do an un-protected check to see if the inode is dirty and