From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mail-iw0-f174.google.com ([209.85.214.174]:46054 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754179Ab1GLTTK convert rfc822-to-8bit (ORCPT ); Tue, 12 Jul 2011 15:19:10 -0400 Received: by iwn6 with SMTP id 6so4910835iwn.19 for ; Tue, 12 Jul 2011 12:19:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <9CD6ADB9-F3AD-47EE-BF7E-251D86B7B305@mit.edu> References: <201107112259.55340.vapier@gentoo.org> <9CD6ADB9-F3AD-47EE-BF7E-251D86B7B305@mit.edu> From: Mike Frysinger Date: Tue, 12 Jul 2011 15:18:50 -0400 Message-ID: Subject: Re: `fsck -A` and fs-specific options To: Theodore Tso Cc: util-linux@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: util-linux-owner@vger.kernel.org List-ID: On Tue, Jul 12, 2011 at 07:02, Theodore Tso wrote: > On Jul 11, 2011, at 10:59 PM, Mike Frysinger wrote: >> for example, some journaling file systems allow the journal to be stored >> separately.  reiserfs has the "jdev=" mount option and the "--journal" fsck >> option.  ext[34] have the "journal_dev=" mount option and the "-j" fsck >> option. > > At least for ext[34] and external journals, e2fsck can find the external > journal using the blkid library since the UUID of the external journal > is in the superblock.   (In fact that's why the blkid library was originally > written, and why it was originally included as part of e2fsprogs.) when i read the kernel source, that seemed to be the case. but i dont think it's the case for reiserfs, and i think there's a very tiny edge case with ext[34] related to moving the journal, but probably so small we can ignore it :p. >> another example is with loop mounts that take an offset.  fsck cannot operate >> on the loop source as the start of the file is not the image.  it needs to >> first setup the loop with the offset, and then do the fsck on the loop point. >>       /tmp/foo.img /mnt/tmp ext3 loop,offset=10000 > > How often are people using loopback mounts as a default, standard thing which > need to be mounted and checked as part of the boot sequence?   I'm just > curious what the use case is for this? common enough that i got a report on it ;). it was a mount point to be checked/mounted during boot. > I suppose if this was something people really did care about, the /etc/fstab > format could be extended to add a new field at the end for fsck options --- > but it's more complexity, and could break programs try to programmatically > modify /etc/fstab. right, which is why i was thinking that parsing the fstab's options field is the lesser of two evils ... -mike