From owner-freebsd-current@FreeBSD.ORG  Tue Sep  6 07:57:12 2005
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
X-Original-To: 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 9055016A41F
	for <current@FreeBSD.org>; Tue,  6 Sep 2005 07:57:12 +0000 (GMT)
	(envelope-from truckman@FreeBSD.org)
Received: from gw.catspoiler.org (217-ip-163.nccn.net [209.79.217.163])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 470A343D45
	for <current@FreeBSD.org>; Tue,  6 Sep 2005 07:57:12 +0000 (GMT)
	(envelope-from truckman@FreeBSD.org)
Received: from FreeBSD.org (mousie.catspoiler.org [192.168.101.2])
	by gw.catspoiler.org (8.13.3/8.13.3) with ESMTP id j867v42t031957;
	Tue, 6 Sep 2005 00:57:08 -0700 (PDT)
	(envelope-from truckman@FreeBSD.org)
Message-Id: <200509060757.j867v42t031957@gw.catspoiler.org>
Date: Tue, 6 Sep 2005 00:57:04 -0700 (PDT)
From: Don Lewis <truckman@FreeBSD.org>
To: phk@haven.freebsd.dk
In-Reply-To: <63946.1125992673@phk.freebsd.dk>
MIME-Version: 1.0
Content-Type: TEXT/plain; charset=us-ascii
Cc: current@FreeBSD.org
Subject: Re: patch for ext2fs unmount problem at shutdown 
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
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: Tue, 06 Sep 2005 07:57:12 -0000

On  6 Sep, Poul-Henning Kamp wrote:
> In message <200509060739.j867dT0x031916@gw.catspoiler.org>, Don Lewis writes:
>>Attached below is a patch to fix the problem caused by having any ext2fs
>>file systems mounted at system shutdown time that prevents any of the
>>file systems from being unmounted and then being marked dirty when the
>>system comes back up.  It works by tweaking ext2fs so that it marks the
>>bufs that it keeps locked as long as the file system is mounted, and
>>tweaks the shutdown code to ignore these bufs when it is counting the
>>number of busy buffers.
> 
> Why is this necessary ?  As far as I know we do an orderly unmount
> of all filesystems at shutdown, so shouldn't ext2fs release the
> buffers at that time ?

We count the busy buffers before unmounting anything, and skip the
unmount if the count is nonzero.

                if (nbusy) {
                        /*
                         * Failed to sync all blocks. Indicate this and don't
                         * unmount filesystems (thus forcing an fsck on reboot).
                         */
                        printf("Giving up on %d buffers\n", nbusy);
                        DELAY(5000000); /* 5 seconds */
                } else {
                        if (!first_buf_printf)
                                printf("Final sync complete\n");
                        /*
                         * Unmount filesystems
                         */
                        if (panicstr == 0)
                                vfs_unmountall();
                }

It would be nice if we only skipped unmounting those file systems that
failed to sync.