From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760191Ab3GaNpz (ORCPT ); Wed, 31 Jul 2013 09:45:55 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46956 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759739Ab3GaNZq (ORCPT ); Wed, 31 Jul 2013 09:25:46 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Josef Bacik" , "Alex Lyakas" Date: Wed, 31 Jul 2013 15:23:09 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [54/84] Btrfs: fix lock leak when resuming snapshot deletion In-Reply-To: X-SA-Exim-Connect-IP: 151.216.67.181 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik commit fec386ac1428f9c0e672df952cbca5cebd4e4e2f upstream. We aren't setting path->locks[level] when we resume a snapshot deletion which means we won't unlock the buffer when we free the path. This causes deadlocks if we happen to re-allocate the block before we've evicted the extent buffer from cache. Thanks, Reported-by: Alex Lyakas Signed-off-by: Josef Bacik Signed-off-by: Ben Hutchings --- fs/btrfs/extent-tree.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6614,6 +6614,7 @@ void btrfs_drop_snapshot(struct btrfs_ro while (1) { btrfs_tree_lock(path->nodes[level]); btrfs_set_lock_blocking(path->nodes[level]); + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; ret = btrfs_lookup_extent_info(trans, root, path->nodes[level]->start, @@ -6627,6 +6628,7 @@ void btrfs_drop_snapshot(struct btrfs_ro break; btrfs_tree_unlock(path->nodes[level]); + path->locks[level] = 0; WARN_ON(wc->refs[level] != 1); level--; }