From: Andreas Dilger Subject: Re: Recovering a damaged ext4 fs - revisited. Date: Thu, 05 Feb 2009 23:29:02 -0700 Message-ID: <20090206062901.GM3209@webber.adilger.int> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: linux-ext4@vger.kernel.org To: "J.D. Bakker" Return-path: Received: from sca-es-mail-1.Sun.COM ([192.18.43.132]:53661 "EHLO sca-es-mail-1.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751341AbZBFG3T (ORCPT ); Fri, 6 Feb 2009 01:29:19 -0500 Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-1.sun.com (8.13.7+Sun/8.12.9) with ESMTP id n166TEuw001557 for ; Thu, 5 Feb 2009 22:29:14 -0800 (PST) Content-disposition: inline Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java(tm) System Messaging Server 7.0-3.01 64bit (built Dec 23 2008)) id <0KEM00J00SHGRU00@fe-sfbay-09.sun.com> for linux-ext4@vger.kernel.org; Thu, 05 Feb 2009 22:29:14 -0800 (PST) In-reply-to: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Feb 06, 2009 04:06 +0100, J.D. Bakker wrote: > On reboot the system refused to auto-fsck /dev/md0. A manual e2fsck -nv > /dev/md0 reported: > > e2fsck 1.41.4 (27-Jan-2009) > ./e2fsck/e2fsck: Group descriptors look bad... trying backup blocks... Not sure why it considers the initial group descriptors bad. > Group descriptor 0 checksum is invalid. Fix? no > Group descriptor 1 checksum is invalid. Fix? no > Group descriptor 2 checksum is invalid. Fix? no > [...] > Group descriptor 29808 checksum is invalid. Fix? no Note that the checksums in the backup blocks are probably incorrect, so this isn't itself a problem. > newraidfs contains a file system with errors, check forced. > Pass 1: Checking inodes, blocks, and sizes > Pass 2: Checking directory structure > Pass 3: Checking directory connectivity > Pass 4: Checking reference counts > Pass 5: Checking group summary information > Block bitmap differences: [...] > Fix? no > Free blocks count wrong for group #0 (23513, counted=464). > Fix? no > Free blocks count wrong for group #1 (31743, counted=509). > Fix? no > [...] > Free inodes count wrong for group #7748 (8192, counted=940). > Fix? no > Directories count wrong for group #7748 (0, counted=1). > Fix? no > Free inodes count wrong for group #7749 (8192, counted=8059). > Fix? no > Free inodes count wrong (244195317, counted=237646747). > Fix? no These also look like trivial errors, due to using the backup group descriptors (which are not kept up-to-date. It appears from this e2fsck output that there isn't really anything wrong with the fs. > Error writing block 1 (Attempt to write block from filesystem resulted > in short write). Ignore error? no > Error writing block 2 (Attempt to write block from filesystem resulted > in short write). Ignore error? no > Error writing block 3 (Attempt to write block from filesystem resulted > in short write). Ignore error? no This is a serious problem. > As I said, is there anything I can do to recover my data, or to make > sure this doesn't happen again? I would say to run "e2fsck -fp /dev/XXX" and your data _should_ be there. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.