From: Nix Subject: Re: Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?) Date: Sat, 27 Oct 2012 13:45:25 +0100 Message-ID: <873910xevu.fsf@spindle.srvr.nix> References: <87mwzdnuww.fsf@spindle.srvr.nix> <20121023143019.GA3040@fieldses.org> <874nllxi7e.fsf_-_@spindle.srvr.nix> <87pq48nbyz.fsf_-_@spindle.srvr.nix> <508AF3FA.4020506@redhat.com> <87wqydx957.fsf@spindle.srvr.nix> <20121026205618.GC8614@thunk.org> <87objpx84k.fsf@spindle.srvr.nix> <20121026211542.GE8614@thunk.org> <87haphx76u.fsf@spindle.srvr.nix> <20121027002258.GB31030@thunk.org> Mime-Version: 1.0 Content-Type: text/plain Cc: Eric Sandeen , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org To: "Theodore Ts'o" Return-path: Received: from icebox.esperi.org.uk ([81.187.191.129]:44056 "EHLO mail.esperi.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751968Ab2J0Mpe (ORCPT ); Sat, 27 Oct 2012 08:45:34 -0400 In-Reply-To: <20121027002258.GB31030@thunk.org> (Theodore Ts'o's message of "Fri, 26 Oct 2012 20:22:58 -0400") Sender: linux-ext4-owner@vger.kernel.org List-ID: [nfs people purged from Cc] On 27 Oct 2012, Theodore Ts'o verbalised: > Huh? It's not turned on by default. If you mount with no mount > options, journal checksums are *not* turned on. ?! it's turned on for me, and though I use weird mount options I don't use that one: /dev/main/var /var ext4 defaults,nobarrier,usrquota,grpquota,nosuid,nodev,relatime,journal_async_commit,commit=30,user_xattr,acl 1 2 Default mount options: (none) /dev/mapper/main-var /var ext4 rw,nosuid,nodev,relatime,journal_checksum,journal_async_commit,nobarrier,quota,usrquota,grpquota,commit=30,stripe=16,data=ordered,usrquota,grpquota 0 0 ... Ah! it's turned on by journal_async_commit. OK, that alone argues against use of journal_async_commit, tested or not, and I'd not have turned it on if I'd noticed that. (So, the combinations I'll be trying for effect on this bug are: journal_async_commit (as now) journal_checksum none Technically to investigate all possibilities we should try journal_async_commit,no_journal_checksum, but this seems so unlikely to have ever been tested by anyone that it's not worth looking into...) -- NULL && (void)