From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Boldi Subject: Re: [RFD] Incremental fsck Date: Wed, 9 Jan 2008 14:52:14 +0300 Message-ID: <200801091452.14890.a1426z@gawab.com> References: <200801090022.55589.a1426z@gawab.com> <200801090740.12989.a1426z@gawab.com> <70b6f0bf0801082345vf57951ey642e35c3d6e5194f@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: "Rik van Riel" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: "Valerie Henson" Return-path: Received: from [212.12.190.220] ([212.12.190.220]:42387 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750756AbYAILzM (ORCPT ); Wed, 9 Jan 2008 06:55:12 -0500 In-Reply-To: <70b6f0bf0801082345vf57951ey642e35c3d6e5194f@mail.gmail.com> Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Valerie Henson wrote: > On Jan 8, 2008 8:40 PM, Al Boldi wrote: > > Rik van Riel wrote: > > > Al Boldi wrote: > > > > Has there been some thought about an incremental fsck? > > > > > > > > You know, somehow fencing a sub-dir to do an online fsck? > > > > > > Search for "chunkfs" > > > > Sure, and there is TileFS too. > > > > But why wouldn't it be possible to do this on the current fs > > infrastructure, using just a smart fsck, working incrementally on some > > sub-dir? > > Several data structures are file system wide and require finding every > allocated file and block to check that they are correct. In > particular, block and inode bitmaps can't be checked per subdirectory. Ok, but let's look at this a bit more opportunistic / optimistic. Even after a black-out shutdown, the corruption is pretty minimal, using ext3fs at least. So let's take advantage of this fact and do an optimistic fsck, to assure integrity per-dir, and assume no external corruption. Then we release this checked dir to the wild (optionally ro), and check the next. Once we find external inconsistencies we either fix it unconditionally, based on some preconfigured actions, or present the user with options. All this could be per-dir or using some form of on-the-fly file-block-zoning. And there probably is a lot more to it, but it should conceptually be possible, with more thoughts though... > http://infohost.nmt.edu/~val/review/chunkfs.pdf Thanks! -- Al