Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965288Ab1C3Vfj (ORCPT ); Wed, 30 Mar 2011 17:35:39 -0400 Received: from mga02.intel.com ([134.134.136.20]:26918 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964935Ab1C3VI3 (ORCPT ); Wed, 30 Mar 2011 17:08:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,270,1299484800"; d="scan'208";a="621237852" From: Andi Kleen References: <20110330203.501921634@firstfloor.org> In-Reply-To: <20110330203.501921634@firstfloor.org> To: johunt@akamai.com, viro@ZenIV.linux.org.uk, jack@suse.cz, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [165/275] ext2: Fix link count corruption under heavy link+rename load Message-Id: <20110330210647.744503E1A05@tassilo.jf.intel.com> Date: Wed, 30 Mar 2011 14:06:47 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2576 Lines: 73 2.6.35-longterm review patch. If anyone has any objections, please let me 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 Signed-off-by: Andi Kleen --- fs/ext2/namei.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) Index: linux-2.6.35.y/fs/ext2/namei.c =================================================================== --- linux-2.6.35.y.orig/fs/ext2/namei.c 2011-03-29 22:50:58.827753164 -0700 +++ linux-2.6.35.y/fs/ext2/namei.c 2011-03-29 23:03:01.688256973 -0700 @@ -344,7 +344,6 @@ new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &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, 1); new_inode->i_ctime = CURRENT_TIME_SEC; if (dir_de) @@ -356,12 +355,9 @@ 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); } @@ -369,12 +365,11 @@ /* * 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) { if (old_dir != new_dir) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/