From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932074AbVIEODR (ORCPT ); Mon, 5 Sep 2005 10:03:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751262AbVIEODR (ORCPT ); Mon, 5 Sep 2005 10:03:17 -0400 Received: from thunk.org ([69.25.196.29]:14052 "EHLO thunker.thunk.org") by vger.kernel.org with ESMTP id S1751254AbVIEODQ (ORCPT ); Mon, 5 Sep 2005 10:03:16 -0400 Date: Mon, 5 Sep 2005 10:03:19 -0400 From: "Theodore Ts'o" To: Pavel Machek Cc: David Teigland , Andrew Morton , Alan Cox , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cluster@redhat.com Subject: Re: real read-only [was Re: GFS, what's remaining] Message-ID: <20050905140318.GA10751@thunk.org> Mail-Followup-To: Theodore Ts'o , Pavel Machek , David Teigland , Andrew Morton , Alan Cox , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cluster@redhat.com References: <20050901104620.GA22482@redhat.com> <20050901035939.435768f3.akpm@osdl.org> <1125586158.15768.42.camel@localhost.localdomain> <20050901132104.2d643ccd.akpm@osdl.org> <20050903051841.GA13211@redhat.com> <20050904203344.GA1987@elf.ucw.cz> <20050905055428.GA29158@thunk.org> <20050905082735.GA2662@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050905082735.GA2662@elf.ucw.cz> User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 05, 2005 at 10:27:35AM +0200, Pavel Machek wrote: > > There's a better reason, too. I do swsusp. Then I'd like to boot with > / mounted read-only (so that I can read my config files, some > binaries, and maybe suspended image), but I absolutely may not write > to disk at this point, because I still want to resume. > You could _hope_ that the filesystem is consistent enough that it is safe to try to read config files, binaries, etc. without running the journal, but there is absolutely no guarantee that this is the case. I'm not sure you want to depend on that for swsusp. One potential solution that would probably meet your needs is a dm hack which reads in the blocks in the journal, and then uses the most recent block in the journal in preference to the version on disk. - Ted