From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966055Ab3GSFs5 (ORCPT ); Fri, 19 Jul 2013 01:48:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39386 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965263Ab3GSFWO (ORCPT ); Fri, 19 Jul 2013 01:22:14 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Schmidt , Josef Bacik Subject: [ 29/38] Btrfs: only do the tree_mod_log_free_eb if this is our last ref Date: Thu, 18 Jul 2013 22:21:45 -0700 Message-Id: <20130719052049.866569137@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20130719052047.858393825@linuxfoundation.org> References: <20130719052047.858393825@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik commit 7fb7d76f96bfcbea25007d190ba828b18e13d29d upstream. There is another bug in the tree mod log stuff in that we're calling tree_mod_log_free_eb every single time a block is cow'ed. The problem with this is that if this block is shared by multiple snapshots we will call this multiple times per block, so if we go to rewind the mod log for this block we'll BUG_ON() in __tree_mod_log_rewind because we try to rewind a free twice. We only want to call tree_mod_log_free_eb if we are actually freeing the block. With this patch I no longer hit the panic in __tree_mod_log_rewind. Thanks, Reviewed-by: Jan Schmidt Signed-off-by: Josef Bacik Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/ctree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1049,7 +1049,8 @@ static noinline int __btrfs_cow_block(st btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); - tree_mod_log_free_eb(root->fs_info, buf); + if (last_ref) + tree_mod_log_free_eb(root->fs_info, buf); btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); }