From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754476AbYDJGPW (ORCPT ); Thu, 10 Apr 2008 02:15:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752265AbYDJGPJ (ORCPT ); Thu, 10 Apr 2008 02:15:09 -0400 Received: from main.gmane.org ([80.91.229.2]:41275 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175AbYDJGPI (ORCPT ); Thu, 10 Apr 2008 02:15:08 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: "Mario 'BitKoenig' Holbe" Subject: Re: Data corruption on software RAID Date: Thu, 10 Apr 2008 08:14:36 +0200 Organization: Technische Universitaet Ilmenau, Germany Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: p4fd56835.dip.t-dialin.net User-Agent: slrn/pre0.9.9-97 (Debian) Cc: linux-raid@vger.kernel.org, dm-devel@redhat.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mikulas Patocka wrote: > During source code review, I found an unprobable but possible data > corruption on RAID-1 and on DM-RAID-1. (I'm not sure about RAID-4,5,6). > > The RAID code was enhanced with bitmaps in 2.6.13. ... > The developers assume that when all writes to the region finish, the > region is in-sync. Just for the records: You don't need bitmaps for that, this happens on plain non-bitmapped devices as well. I had an interesting discussion about this with Heinz Mauelshagen on the linux-raid list back in early 2006 starting with Message-ID: And it's not that unlikely at all. I experience such inconsistencies regularly on ext2/3 filesystems with heavy inode fluctuations (for example via cp -al; rsync, like rsnapshot does). I periodically sync these inconsistencies manual. However, it always seems to appear with inode removal only, which is rather harmless. regards Mario -- I've never been certain whether the moral of the Icarus story should only be, as is generally accepted, "Don't try to fly too high," or whether it might also be thought of as, "Forget the wax and feathers and do a better job on the wings." -- Stanley Kubrick