gfs2: Fix error exit in do_xmote

Before this patch, if an error was detected from glock function go_sync
by function do_xmote, it would return.  But the function had temporarily
unlocked the gl_lockref spin_lock, and it never re-locked it.  When the
caller of do_xmote tried to unlock it again, it was already unlocked,
which resulted in a corrupted spin_lock value.

This patch makes sure the gl_lockref spin_lock is re-locked after it is
unlocked.

Thanks to Wu Bo <wubo40@huawei.com> for reporting this problem.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -613,7 +613,7 @@ __acquires(&gl->gl_lockref.lock)
 				fs_err(sdp, "Error %d syncing glock \n", ret);
 				gfs2_dump_glock(NULL, gl, true);
 			}
-			return;
+			goto out;
 		}
 	}
 	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) {