From owner-freebsd-current@FreeBSD.ORG  Sun Nov  7 12:16:56 2004
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id E953E16A4CE
	for <current@freebsd.org>; Sun,  7 Nov 2004 12:16:56 +0000 (GMT)
Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 4E3FD43D2F
	for <current@freebsd.org>; Sun,  7 Nov 2004 12:16:56 +0000 (GMT)
	(envelope-from phk@critter.freebsd.dk)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.13.1/8.13.1) with ESMTP id iA7CGsZu022424;
	Sun, 7 Nov 2004 13:16:54 +0100 (CET)
	(envelope-from phk@critter.freebsd.dk)
To: Stefan Ehmann <shoesoft@gmx.net>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Sun, 07 Nov 2004 13:10:38 +0100."
             <1099829438.890.11.camel@taxman> 
Date: Sun, 07 Nov 2004 13:16:54 +0100
Message-ID: <22423.1099829814@critter.freebsd.dk>
Sender: phk@critter.freebsd.dk
cc: current@freebsd.org
Subject: Re: ext2fs related panic 
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 07 Nov 2004 12:16:57 -0000

In message <1099829438.890.11.camel@taxman>, Stefan Ehmann writes:
>On Sat, 2004-11-06 at 19:25, Poul-Henning Kamp wrote:
>> Ok, can you try the stuff in current, I've made two commits
>> and you want both.
>
>Thanks, these fix the previous panics reported by me.
>
>I was able to produce yet another panic:
>
>mount /mnt/stuff
>mount -u -o rw /mnt/stuff
>touch /mnt/stuff/foo
>mount -u -o ro /mnt/stuff
>umount /mnt/stuff
>
>At this point I get this:
>g_vfs_done():ad1s1[WRITE(offset=4096, length=4096)]error = 1
>g_vfs_done():ad1s1[WRITE(offset=8192, length=4096)]error = 1
>g_vfs_done():ad1s1[WRITE(offset=20480, length=4096)]error = 1
>g_vfs_done():ad1s1[WRITE(offset=27380416512, length=4096)]error = 1
>
>A few seconds later I get this:
>Fatal trap 12: page fault while in kernel mode
>current process = 55 (syncer)

this is a long-standing bug in ext2fs which were previously masked
by other issues:  When downgrading a filesystem from r/w to r/o
the dirty buffers are not flushed.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.