Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265479AbTIDSj2 (ORCPT ); Thu, 4 Sep 2003 14:39:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265478AbTIDSh6 (ORCPT ); Thu, 4 Sep 2003 14:37:58 -0400 Received: from thebsh.namesys.com ([212.16.7.65]:63940 "HELO thebsh.namesys.com") by vger.kernel.org with SMTP id S265444AbTIDShL (ORCPT ); Thu, 4 Sep 2003 14:37:11 -0400 Message-ID: <3F578656.60005@namesys.com> Date: Thu, 04 Sep 2003 22:37:10 +0400 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3a) Gecko/20021212 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Mike Fedyk CC: Andrew Morton , reiserfs-list@namesys.com, linux-kernel@vger.kernel.org Subject: Re: precise characterization of ext3 atomicity References: <3F574A49.7040900@namesys.com> <20030904085537.78c251b3.akpm@osdl.org> <3F576176.3010202@namesys.com> <20030904091256.1dca14a5.akpm@osdl.org> <3F57676E.7010804@namesys.com> <20030904181540.GC13676@matchmail.com> In-Reply-To: <20030904181540.GC13676@matchmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1244 Lines: 41 Mike Fedyk wrote: >On Thu, Sep 04, 2003 at 08:25:18PM +0400, Hans Reiser wrote: > > >>In data=journal and data=ordered modes ext3 also guarantees that the >>metadata will be committed atomically with the data they point to. However >>ext3 does not provide user data atomicity guarantees beyond the scope of a >>single filesystem disk block (usually 4 kilobytes). If a single write() >>spans two disk blocks it is possible that a crash partway through the write >>will result in only one of those blocks appearing in the file after >>recovery. >> >> > >And how does reiser4 do this without changing the userspace apps? > We don't. We just make the hovercraft, we don't force you to go over the water..... > >Most files are written with several write() calls, so even if each call is >atomic, your entire file will not be there. > >Also, ext3 could claim the same atomicity if it only updated meta-data on >write() call boundaries, instead of block boundaries. > > > > -- Hans - 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/