[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>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index dbeb4ad836bd76c675683da6d2d86d32b71dd003..7f362d0c3f7aac5233f95d18386a79a71571b5a1 100644 (file)
--- 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);