[GFS2] Correct logic in glock scanner

Under certain circumstances the glock scanning logic would
demote locks which ought not to have been selected for
demotion.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index dbeb4ad836bd..7f362d0c3f7a 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1967,8 +1967,11 @@ static void scan_glock(struct gfs2_glock *gl)
         if (gfs2_glmutex_trylock(gl)) {
                 if (gl->gl_ops == &gfs2_inode_glops) {
                         struct gfs2_inode *ip = gl->gl_object;
-                        if (ip)
+                        if (ip == NULL) {
+                                struct gfs2_sbd *sdp = gl->gl_sbd;
+                                gfs2_assert_withdraw(sdp, gl->gl_state == LM_ST_UNLOCKED);
                                 goto out_schedule;
+                        }
                 }
                 if (queue_empty(gl, &gl->gl_holders) &&
                     gl->gl_state != LM_ST_UNLOCKED &&
@@ -1982,7 +1985,7 @@ static void scan_glock(struct gfs2_glock *gl)
 
         return;
 
- out_schedule:
+out_schedule:
         gfs2_glmutex_unlock(gl);
         gfs2_glock_schedule_for_reclaim(gl);
         gfs2_glock_put(gl);