From: Nix Subject: Re: Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?) Date: Fri, 26 Oct 2012 21:59:07 +0100 Message-ID: <87objpx84k.fsf@spindle.srvr.nix> References: <87objupjlr.fsf@spindle.srvr.nix> <20121023013343.GB6370@fieldses.org> <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> Mime-Version: 1.0 Content-Type: text/plain Cc: Eric Sandeen , linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "J. Bruce Fields" , Bryan Schumaker , Peng Tao , Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Theodore Ts'o" Return-path: In-Reply-To: <20121026205618.GC8614-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org> (Theodore Ts'o's message of "Fri, 26 Oct 2012 16:56:18 -0400") Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On 26 Oct 2012, Theodore Ts'o stated: > On Fri, Oct 26, 2012 at 09:37:08PM +0100, Nix wrote: >> >> I can reproduce this on a small filesystem and stick the image somewhere >> if that would be of any use to anyone. (If I'm very lucky, merely making >> this offer will make the problem go away. :} ) > > I'm not sure the image is going to be that useful. What we really > need to do is to get a reliable reproduction of what _you_ are seeing. > > It's clear from Eric's experiments that journal_checksum is dangerous. > > That's why one of the things I asked you to do when you had time was > to see if you could reproduce the problem you are seeing w/o > nobarrier,journal_checksum,journal_async_commit. OK. Will do tomorrow. > The other experiment that would be really useful if you could do is to > try to apply these two patches which I sent earlier this week: > > [PATCH 1/2] ext4: revert "jbd2: don't write superblock when if its empty > [PATCH 2/2] ext4: fix I/O error when unmounting an ro file system > > ... and see if they make a difference. As of tomorrow I'll be able to reboot without causing a riot: I'll test it then. (Sorry for the delay :( ) > So I really don't want > to push these patches to Linus until I get confirmation that they make > a difference to *somebody*. Agreed. This isn't the first time that journal_checksum has proven problematic. It's a shame that we're stuck between two error-inducing stools here... -- NULL && (void) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html