From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933924AbaICWS5 (ORCPT ); Wed, 3 Sep 2014 18:18:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46204 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933813AbaICWSv (ORCPT ); Wed, 3 Sep 2014 18:18:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Chris Mason Subject: [PATCH 3.16 086/125] Btrfs: read lock extent buffer while walking backrefs Date: Wed, 3 Sep 2014 15:07:23 -0700 Message-Id: <20140903220626.255378126@linuxfoundation.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <20140903220623.649748296@linuxfoundation.org> References: <20140903220623.649748296@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Filipe Manana commit 6f7ff6d7832c6be13e8c95598884dbc40ad69fb7 upstream. Before processing the extent buffer, acquire a read lock on it, so that we're safe against concurrent updates on the extent buffer. Signed-off-by: Filipe Manana Signed-off-by: Chris Mason Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/backref.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1000,8 +1000,11 @@ again: ret = -EIO; goto out; } + btrfs_tree_read_lock(eb); + btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); ret = find_extent_in_eb(eb, bytenr, *extent_item_pos, &eie); + btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); if (ret < 0) goto out;