From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932144Ab1DYUYW (ORCPT ); Mon, 25 Apr 2011 16:24:22 -0400 Received: from 1wt.eu ([62.212.114.60]:33962 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756870Ab1DYUYP (ORCPT ); Mon, 25 Apr 2011 16:24:15 -0400 Message-Id: <20110425200235.774417396@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 25 Apr 2011 22:03:36 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: Al Viro , Josh Hunt , Jan Kara , Greg Kroah-Hartman Subject: [PATCH 064/173] ext2: Fix link count corruption under heavy link+rename load In-Reply-To: <46075c3a3ef08be6d70339617d6afc98@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.59-stable review patch. If anyone has any objections, please let us know. ------------------ From: Josh Hunt commit e8a80c6f769dd4622d8b211b398452158ee60c0b upstream. vfs_rename_other() does not lock renamed inode with i_mutex. Thus changing i_nlink in a non-atomic manner (which happens in ext2_rename()) can corrupt it as reported and analyzed by Josh. In fact, there is no good reason to mess with i_nlink of the moved file. We did it presumably to simulate linking into the new directory and unlinking from an old one. But the practical effect of this is disputable because fsck can possibly treat file as being properly linked into both directories without writing any error which is confusing. So we just stop increment-decrement games with i_nlink which also fixes the corruption. CC: Al Viro Signed-off-by: Josh Hunt Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/ext2/namei.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) Index: longterm-2.6.27/fs/ext2/namei.c =================================================================== --- longterm-2.6.27.orig/fs/ext2/namei.c 2011-01-23 10:52:28.000000000 +0100 +++ longterm-2.6.27/fs/ext2/namei.c 2011-04-25 15:14:36.125277949 +0200 @@ -322,7 +322,6 @@ new_de = ext2_find_entry (new_dir, new_dentry, &new_page); if (!new_de) goto out_dir; - inode_inc_link_count(old_inode); ext2_set_link(new_dir, new_de, new_page, old_inode); new_inode->i_ctime = CURRENT_TIME_SEC; if (dir_de) @@ -334,12 +333,9 @@ if (new_dir->i_nlink >= EXT2_LINK_MAX) goto out_dir; } - inode_inc_link_count(old_inode); err = ext2_add_link(new_dentry, old_inode); - if (err) { - inode_dec_link_count(old_inode); + if (err) goto out_dir; - } if (dir_de) inode_inc_link_count(new_dir); } @@ -347,12 +343,11 @@ /* * Like most other Unix systems, set the ctime for inodes on a * rename. - * inode_dec_link_count() will mark the inode dirty. */ old_inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(old_inode); ext2_delete_entry (old_de, old_page); - inode_dec_link_count(old_inode); if (dir_de) { ext2_set_link(old_inode, dir_de, dir_page, new_dir);