From owner-freebsd-current@FreeBSD.ORG Sun Oct 11 12:51:00 2009 Return-Path: Delivered-To: freebsd-current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 529F91065693 for ; Sun, 11 Oct 2009 12:51:00 +0000 (UTC) (envelope-from gavin@FreeBSD.org) Received: from mail-gw1.york.ac.uk (mail-gw1.york.ac.uk [144.32.128.246]) by mx1.freebsd.org (Postfix) with ESMTP id E09ED8FC15 for ; Sun, 11 Oct 2009 12:50:59 +0000 (UTC) Received: from mail-gw7.york.ac.uk (mail-gw7.york.ac.uk [144.32.129.30]) by mail-gw1.york.ac.uk (8.13.6/8.13.6) with ESMTP id n9BCov8P029712; Sun, 11 Oct 2009 13:50:57 +0100 (BST) Received: from ury.york.ac.uk ([144.32.108.81]) by mail-gw7.york.ac.uk with esmtps (TLSv1:AES256-SHA:256) (Exim 4.68) (envelope-from ) id 1Mwxt3-0001XW-Ci; Sun, 11 Oct 2009 13:50:57 +0100 Received: from ury.york.ac.uk (localhost.york.ac.uk [127.0.0.1]) by ury.york.ac.uk (8.14.3/8.14.3) with ESMTP id n9BCovwX028693; Sun, 11 Oct 2009 13:50:57 +0100 (BST) (envelope-from gavin@FreeBSD.org) Received: from localhost (gavin@localhost) by ury.york.ac.uk (8.14.3/8.14.3/Submit) with ESMTP id n9BCovgD028690; Sun, 11 Oct 2009 13:50:57 +0100 (BST) (envelope-from gavin@FreeBSD.org) X-Authentication-Warning: ury.york.ac.uk: gavin owned process doing -bs Date: Sun, 11 Oct 2009 13:50:57 +0100 (BST) From: Gavin Atkinson X-X-Sender: gavin@ury.york.ac.uk To: David Ehrmann In-Reply-To: <4AD0E286.9030508@gmail.com> Message-ID: <20091011133411.A80896@ury.york.ac.uk> References: <4AD0E286.9030508@gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-York-MailScanner: Found to be clean X-York-MailScanner-From: gavin@freebsd.org Cc: daichi@FreeBSD.org, freebsd-current@FreeBSD.org Subject: Re: Strange md/unionfs issue X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Oct 2009 12:51:00 -0000 On Sat, 10 Oct 2009, David Ehrmann wrote: > I have a system running on a flash disk. To prevent it from wearing out > quickly, I don't run with a swap and mount /tmp and /var from memory. > Because /var needs some directories and contains files I probably should save > from time to time, I mount it from flash, mount /var to /var_real so I can > access the underlying files, and then I mount an md device on top of /var as > a unionfs. Initially, it seems to work, but seconds later, the unionfs seems > to fail. When the mount "fails", is it still shown in the output of mount(1)? It appears that this problem is the same as is reported in PR kern/131441, which has so far not had any activity. It appears that this bug has existed since at least 7.1-RELEASE. I've included Goto-san in the CC-list, as he may be able to see if this is a bug in unionfs or in nullfs. Thanks, Gavin