Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 26 Jul 2001 09:52:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 26 Jul 2001 09:52:12 -0400 Received: from router-100M.swansea.linux.org.uk ([194.168.151.17]:61196 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Thu, 26 Jul 2001 09:52:05 -0400 Subject: Re: ext3-2.4-0.9.4 To: matthias.andree@stud.uni-dortmund.de (Matthias Andree) Date: Thu, 26 Jul 2001 14:52:21 +0100 (BST) Cc: riel@conectiva.com.br (Rik van Riel), matthias.andree@stud.uni-dortmund.de (Matthias Andree), akpm@zip.com.au (Andrew Morton), linux-kernel@vger.kernel.org (lkml), ext3-users@redhat.com (ext3-users@redhat.com) In-Reply-To: <20010726151749.M17244@emma1.emma.line.org> from "Matthias Andree" at Jul 26, 2001 03:17:49 PM X-Mailer: ELM [version 2.5 PL5] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Original-Recipient: rfc822;linux-kernel-outgoing > On Thu, 26 Jul 2001, Rik van Riel wrote: > > In fact, knowing how hard disks work mechanically, only > > journaling filesystems could have an extention to make > > this work. Ie. this is NOT something you can rely on ;) > > This is not about failing hard disks. It is about premature > acknowledgment of something which has not happened at that time. Rik is right. It isnt just about premature notification - its about atomicity. At the point you are notified the data has been queued for disk I/O. Even on traditional BSD ufs with synchronous metadata you still had points where a crash left the rename partially complete and nothing but a log or an atomic update system is going to fix that. > The competition is there and it has names: BSD + ufs + softupdates, > Solaris + logging ufs. Read MTA mailing lists before obstructing. All of which are - not unsuprisingly - using a log. In fact Solaris logging ufs and ext3 are very similar ideas - adding a log to an existing fs. Alan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/