From owner-freebsd-fs@FreeBSD.ORG Tue Mar 20 06:59:07 2007 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 18D9316A404; Tue, 20 Mar 2007 06:59:07 +0000 (UTC) (envelope-from david.cecil@nokia.com) Received: from mgw-ext13.nokia.com (smtp.nokia.com [131.228.20.172]) by mx1.freebsd.org (Postfix) with ESMTP id 922C813C480; Tue, 20 Mar 2007 06:59:06 +0000 (UTC) (envelope-from david.cecil@nokia.com) Received: from esebh107.NOE.Nokia.com (esebh107.ntc.nokia.com [172.21.143.143]) by mgw-ext13.nokia.com (Switch-3.2.5/Switch-3.2.5) with ESMTP id l2K6x1te015105; Tue, 20 Mar 2007 08:59:03 +0200 Received: from siebh101.NOE.Nokia.com ([172.30.195.27]) by esebh107.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 20 Mar 2007 08:58:41 +0200 Received: from syebe101.NOE.Nokia.com ([172.30.128.65]) by siebh101.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 20 Mar 2007 14:58:18 +0800 Received: from [172.30.10.156] ([172.30.10.156]) by syebe101.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 20 Mar 2007 17:58:16 +1100 Message-ID: <45FF8607.8060501@nokia.com> Date: Tue, 20 Mar 2007 16:58:15 +1000 From: David Cecil User-Agent: Thunderbird 1.5.0.9 (Windows/20061207) MIME-Version: 1.0 To: ext Pawel Jakub Dawidek , ext Kris Kennaway References: <45F776AE.8090702@nokia.com> <20070314161041.GI7847@garage.freebsd.pl> <45F8EE27.6070208@nokia.com> <20070315090031.GB80993@deviant.kiev.zoral.com.ua> <20070315092659.GA14080@garage.freebsd.pl> <45F9C9B4.4030508@nokia.com> <20070315223641.GA89923@xor.obsecurity.org> <45F9CBCC.7050006@nokia.com> <20070316014846.GA3229@garage.freebsd.pl> <45F9F994.2050803@nokia.com> <45FE1BA0.5080609@nokia.com> In-Reply-To: <45FE1BA0.5080609@nokia.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 20 Mar 2007 06:58:16.0429 (UTC) FILETIME=[228BA9D0:01C76ABD] X-eXpurgate-Category: 1/0 X-eXpurgate-ID: 149371::070320085903-3AF4DBB0-791C157F/0-0/0-1 X-Nokia-AV: Clean Cc: freebsd-fs@freebsd.org Subject: Re: FFS writes to read-only mount X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Mar 2007 06:59:07 -0000 ext David Cecil wrote: > >>> Could you try disabling bgfsck, by setting background_fsck="NO" to your >>> /etc/rc.conf? >>> >> >> Yes, I could do that. Again, I'm reluctant to try the experiment >> before getting as much information as possible from ddb. >> >> From the fsck_ffs man page: >> "To be eligible for background cleaning it must have been running >> with soft updates, not have been marked as needing a foreground >> check, and be mounted and writable when the background check is to be >> done. If these conditions are met, then fsck_ffs exits with a zero >> exit status. Otherwise it exits with a non-zero exit status. If the >> file system is clean, it will exit with a non-zero exit status so >> that the clean status of the file system can be verified and reported >> during the foreground checks." >> >> This says the partition must be writable when the check is done. Now >> I guess there could be a bug where it's trying to write when it >> shouldn't... Maybe I should take a look at the fsck_ffs code too. >> >>> I know that there is a hack for handling fsck of the root file system. >>> Bascially once system is mounted read-only (the partition it resides on >>> is opened read-only), it (the partition) can't be opened for write by >>> anything else (because of how GEOM works). But there is an exception >>> for >>> the root partition, which is opened without exclusive bit at first >>> time, >>> which allows, eg. to boot system into single-user mode and run fsck - >>> without this hack it won't be possible. So I'm wondering if this can be >>> problematic if one use bgfsck for the root file system... >>> >> >> I will look into it some more and report back. >> > > I discovered this morning that the messages were no longer being > displayed on the console. I set a breakpoint in sync_vnode and the > bufobj corresponding to the problematic buffer is no longer being > passed in. > > I looked back through the history of commands and it appears this was > the result of an fsck command I issued. The command that I think > stopped it is: > # fsck_ffs -B / > MOUNTED READ-ONLY, CANNOT RUN IN BACKGROUND > ** /dev/mirror/gmroots1f (NO WRITE) > ** Last Mounted on / > ** Root file system > ** Phase 1 - Check Blocks and Sizes > ** Phase 2 - Check Pathnames > ** Phase 3 - Check Connectivity > ** Phase 4 - Check Reference Counts > UNREF FILE I=165196 OWNER=root MODE=100644 > SIZE=0 MTIME=Mar 9 03:55 2007 > CLEAR? no The problem appeared on another machine today and after I issued the "fsck_ff -B /", the console message was no longer printed. I'm going to try and determine if the umount/remount is not causing all buffers to be flushed before the underlying device becomes read-only. Regards, Dave -- Software Engineer Secure and Mobile Connectivity Nokia Enterprise Solutions +61 7 5553 8307 (office) +61 412 728 222 (cell)