From owner-freebsd-hackers@FreeBSD.ORG Tue Dec 18 10:38:23 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 918CE16A418 for ; Tue, 18 Dec 2007 10:38:23 +0000 (UTC) (envelope-from ntarmos@ceid.upatras.gr) Received: from poseidon.ceid.upatras.gr (poseidon.ceid.upatras.gr [150.140.141.169]) by mx1.freebsd.org (Postfix) with ESMTP id 005C613C47E for ; Tue, 18 Dec 2007 10:38:22 +0000 (UTC) (envelope-from ntarmos@ceid.upatras.gr) Received: from mail.ceid.upatras.gr (unknown [10.1.0.143]) by poseidon.ceid.upatras.gr (Postfix) with ESMTP id A6352EB464B for ; Tue, 18 Dec 2007 12:38:21 +0200 (EET) Received: from localhost (europa.ceid.upatras.gr [127.0.0.1]) by mail.ceid.upatras.gr (Postfix) with ESMTP id 8F2AC1584F7 for ; Tue, 18 Dec 2007 12:38:21 +0200 (EET) X-Virus-Scanned: amavisd-new at ceid.upatras.gr Received: from mail.ceid.upatras.gr ([127.0.0.1]) by localhost (europa.ceid.upatras.gr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id r4Q6fJMovhWW for ; Tue, 18 Dec 2007 12:38:21 +0200 (EET) Received: from ace.netcins.ceid.upatras.gr (vfppp079167010077.dsl.hol.gr [79.167.10.77]) by mail.ceid.upatras.gr (Postfix) with ESMTP id 19B1215809E for ; Tue, 18 Dec 2007 12:38:21 +0200 (EET) Received: by ace.netcins.ceid.upatras.gr (Postfix, from userid 1001) id 6E3433F450; Tue, 18 Dec 2007 07:52:01 +0200 (EET) Date: Tue, 18 Dec 2007 07:52:01 +0200 From: Nikos Ntarmos To: freebsd-hackers@freebsd.org Message-ID: <20071218055201.GB51227@ace.netcins.ceid.upatras.gr> Mail-Followup-To: freebsd-hackers@freebsd.org References: <1197889622.4766585626a92@webmail.rawbw.com> <1197916368.4766c0d0db6a8@webmail.rawbw.com> <20071218001355.GA40289@marvin.blogreen.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; x-action=pgp-signed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20071218001355.GA40289@marvin.blogreen.org> Organization: NetCInS Lab., C.E.I.D., U. of Patras, Greece WWW-Homepage: http://ntarmos.dyndns.org/ X-PGP-Fingerprint: 9680 60A7 DE60 0298 B1F0 9B22 9BA2 7569 CF95 160A Office-Phone: +30-2610-996919 Office-Fax: +30-2610-969011 GPS-Info: 38.31N, 21.82E User-Agent: mutt-ng/devel-r804 (FreeBSD) Subject: Re: Stale mount on disconnected device: how to delete it? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Dec 2007 10:38:23 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tue, Dec 18, 2007 at 01:13:55AM +0100, Romain Tartière wrote: > On Mon, Dec 17, 2007 at 10:32:48AM -0800, Yuri wrote : > > In case of USB device (which device in question in this problem > > happens to be) usbd can be used to mount it. > > > > If attach/detach events trigger mount/unmount commands this problem > > shouldn't exist. I didn't try though. > > The problem is that the detach event can be caught only too late to > unmount the device properly. How may it be possible to sync a disk > ``as soon as it is detached'' (that is when it is not physically > connected to the computer anymore)? Mounting the disk read-only may > be a workaround, just as not caching writes (default behaviour of some > versions of Windows) and syncing the disk all the time, but this is > not as reliable as the mount system provided by Unix and Unix like > operating systems. > > AFAICR, this is the sole weakness of the FreeBSD operating system I > know :) And since it is, according to me, an operator error, the best > we can do is to use the system as it was designed for ;) Off the top of my head, what is wrong/hard with just logging a device failure, discarding all remaining cached operations, and unmounting the fs when a disk device goes missing? I understand that this is not a viable solution for critical filesystems, but I can see nothing wrong with this approach for removable devices and/or non-critical fs's. Just my $0.02. \n\n -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) Comment: Nikos Ntarmos iD8DBQFHZ2ABm6J1ac+VFgoRAhWtAJ4uomUoe0IDVG0qG2W+t7y9ZSMjugCbBAoz LtIIMhMCk9iZ3NeStO8uwLU= =+o7j -----END PGP SIGNATURE-----