From owner-freebsd-questions@FreeBSD.ORG  Sat May 26 19:25:14 2007
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
X-Original-To: questions@freebsd.org
Delivered-To: freebsd-questions@FreeBSD.ORG
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 9096116A41F
	for <questions@freebsd.org>; Sat, 26 May 2007 19:25:14 +0000 (UTC)
	(envelope-from freebsd-questions-local@be-well.ilk.org)
Received: from mail7.sea5.speakeasy.net (mail7.sea5.speakeasy.net
	[69.17.117.9]) by mx1.freebsd.org (Postfix) with ESMTP id 6CCB613C46E
	for <questions@freebsd.org>; Sat, 26 May 2007 19:25:14 +0000 (UTC)
	(envelope-from freebsd-questions-local@be-well.ilk.org)
Received: (qmail 28207 invoked from network); 26 May 2007 19:25:14 -0000
Received: from dsl092-078-145.bos1.dsl.speakeasy.net (HELO be-well.ilk.org)
	([66.92.78.145])
	(envelope-sender <freebsd-questions-local@be-well.ilk.org>)
	by mail7.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP
	for <questions@freebsd.org>; 26 May 2007 19:25:13 -0000
Received: from Lowell-Desk.lan (Lowell-Desk.lan [172.30.250.6])
	by be-well.ilk.org (Postfix) with ESMTP id EA6A428439;
	Sat, 26 May 2007 15:25:09 -0400 (EDT)
Received: by Lowell-Desk.lan (Postfix, from userid 1147)
	id ACFAC1D084; Sat, 26 May 2007 15:25:07 -0400 (EDT)
To: Svein Halvor Halvorsen <svein.h@lvor.halvorsen.cc>
References: <465864F4.7060500@lvor.halvorsen.cc>
	<20070526180336.GB34660@slackbox.xs4all.nl>
	<465884E3.5000500@lvor.halvorsen.cc>
From: Lowell Gilbert <freebsd-questions-local@be-well.ilk.org>
Date: Sat, 26 May 2007 15:25:07 -0400
In-Reply-To: <465884E3.5000500@lvor.halvorsen.cc> (Svein Halvor Halvorsen's
	message of "Sat\, 26 May 2007 21\:05\:07 +0200")
Message-ID: <44odk7fkvg.fsf@Lowell-Desk.lan>
User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.99 (berkeley-unix)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: questions@freebsd.org
Subject: Re: Restore UFS snapshot
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 26 May 2007 19:25:14 -0000

Svein Halvor Halvorsen <svein.h@lvor.halvorsen.cc> writes:

> This is also beyond the point, although I appreciate that you
> suggest alternative ways to meet my objectives. dump/restore would
> also require additional disk space.

Not as elegant as your idea, but you can always dump from the snapshot
and restore back on the filesystem.  You can't use a "pristine"
restore(8), and you need the extra space on the same filesystem, but
it will work.

Your basic idea seems quite workable as far as I can see, so it would
be a Simple Matter of Programming to get it to work.  [Note that since
the copy-on-write mapping only goes one way, the code to do this will
have to walk the whole snapshot filesystem, rebuilding inode status
(and cleaning up ones that didn't exist in the snapshot) as it goes.
A fair amount of work, even if nothing is tricky in theory.]

Be well.