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: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/glock.c

@@ -1816,15 +1816,17 @@ restart:
 	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 @@ restart:
 		if (gi->gl)
 			gfs2_glock_hold(gi->gl);
 		read_unlock(gl_lock_addr(gi->hash));
-		gi->hash++;
 	}
 
 	if (gi->sdp != gi->gl->gl_sbd)