GFS2: Fix debugfs glock file iterator

Due to an incorrect iterator, some glocks were being missed from the
glock dumps obtained via debugfs. This patch fixes the problem and
ensures that we don't miss any glocks in future.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/glock.c

@@ -1816,15 +1816,17 @@ static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
 	if (gl) {
 		gi->gl = hlist_entry(gl->gl_list.next,
 				     struct gfs2_glock, gl_list);
-		if (gi->gl)
-			gfs2_glock_hold(gi->gl);
+	} else {
+		gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
+				     struct gfs2_glock, gl_list);
 	}
+	if (gi->gl)
+		gfs2_glock_hold(gi->gl);
 	read_unlock(gl_lock_addr(gi->hash));
 	if (gl)
 		gfs2_glock_put(gl);
-	if (gl && gi->gl == NULL)
-		gi->hash++;
 	while (gi->gl == NULL) {
+		gi->hash++;
 		if (gi->hash >= GFS2_GL_HASH_SIZE)
 			return 1;
 		read_lock(gl_lock_addr(gi->hash));
@@ -1833,7 +1835,6 @@ static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
 		if (gi->gl)
 			gfs2_glock_hold(gi->gl);
 		read_unlock(gl_lock_addr(gi->hash));
-		gi->hash++;
 	}
 
 	if (gi->sdp != gi->gl->gl_sbd)