From: Andreas Dilger Subject: Re: Add ext4__allow_read-only_mounts_with_corrupted_block_group_checksums patch Date: Wed, 16 Jul 2008 03:29:14 -0600 Message-ID: <20080716092914.GR6239@webber.adilger.int> References: <3.0.6.32.20080715193126.0242c9a0@pop.west.cox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: "linux-ext4@vger.kernel.org" , Theodore Tso To: Gary Hawco Return-path: Received: from sca-es-mail-1.Sun.COM ([192.18.43.132]:58498 "EHLO sca-es-mail-1.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754819AbYGPJ3R (ORCPT ); Wed, 16 Jul 2008 05:29:17 -0400 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 m6G9TGcE004765 for ; Wed, 16 Jul 2008 02:29:16 -0700 (PDT) Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) id <0K4300B01E9NUP00@fe-sfbay-09.sun.com> (original mail from adilger@sun.com) for linux-ext4@vger.kernel.org; Wed, 16 Jul 2008 02:29:16 -0700 (PDT) In-reply-to: <3.0.6.32.20080715193126.0242c9a0@pop.west.cox.net> Content-disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: On Jul 15, 2008 19:31 +0000, Gary Hawco wrote: > Just recompiled 2.6.26 with the newest snapshot (15-July 2008/2310GMT). > uninit_bg had been enabled. > > To test kernel I did: tune2fs -O ^uninit_bg /dev/sda6 to remove uninit_bg > feature. > Was prompted to run e2fsck on system. > > Rebooted and e2fsck saw errors and did a forced fsck without having to > reboot. All is well thus far. You shouldn't really have rebooted at that point, just run e2fsck on the filesystem to clear the checksums. > Then I did the reverse: tune2fs -O uninit_bg /dev/sda6 to renable uninit_bg > feature. Again, I was prompted to run e2fsck on system. Again, you should have just run e2fsck on the filesystem without rebooting, in order to update the checksums. > Rebooted. This time I got a kernel panic that started with: > EXT4-fs: ext4_check_descriptors: Checksum for group 2 failed (10368!=32990) > EXT4-fs: group descriptors corrupted! The kernel thinks the filesystem is corrupted, so a full e2fsck needs to be run. However, e2fsck is probably sitting on that unmountable filesystem. > I was under the impression that the newest patch would handle this or am I > mistaken? We probably need to allow the kernel to mount the filesystem read-only in this case in order to run e2fsck. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.