From: Solofo.Ramangalahy@bull.net Subject: Re: mke2fs and lazy_itable_init Date: Wed, 27 Aug 2008 11:29:13 +0200 Message-ID: <18613.7785.128407.136911@frecb006361.adech.frec.bull.fr> References: <20080508224847.GR3627@webber.adilger.int> <20080509021827.GA8871@mit.edu> <20080509081929.GD3627@webber.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Andreas Dilger To: Theodore Tso Return-path: Received: from ecfrec.frec.bull.fr ([129.183.4.8]:51252 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751912AbYH0J3j (ORCPT ); Wed, 27 Aug 2008 05:29:39 -0400 Cc: linux-ext4@vger.kernel.org In-Reply-To: <20080509081929.GD3627@webber.adilger.int> Sender: linux-ext4-owner@vger.kernel.org List-ID: >>>>> On Fri, 09 May 2008 02:19:30 -0600, Andreas Dilger said: Andreas> On May 08, 2008 22:18 -0400, Theodore Ts'o wrote: >> On Thu, May 08, 2008 at 04:48:47PM -0600, Andreas Dilger wrote: >> > I just noticed lazy_itable_init in the mke2fs.8.in man page. >> I think > a warning needs to be added there that this is not >> currently safe to > use, because the kernel does not yet do the >> background zeroing. There > is nothing in the man page to >> indicate that this is unsafe... >> >> Yeah, I was hoping we would actually get this fixed before 1.41 >> was released.... (i.e., implement the background zeroing). Andreas> It would still be an issue for 2.6.24 and 2.6.25 kernels, Andreas> so I think it at least deserves a warning until there is Andreas> a specific kernel that can be referenced that has this Andreas> functionality. I think this patch (from Andreas) would be good for e2fsprogs 1.41.1, as discussed at Monday call. -- solofo Index: b/misc/mke2fs.8.in =================================================================== --- a/misc/mke2fs.8.in +++ b/misc/mke2fs.8.in @@ -221,6 +221,12 @@ initialization noticeably, but it requir initializing the filesystem in the background when the filesystem is first mounted. If the option value is omitted, it defaults to 1 to enable lazy inode table initialization. +. BR NOTE: +No kernels do the background zeroing of the inode table at this time, +so this option is unsafe for production use, due to the risk of +filesystem corruption if e2fsck has to scan the whole inode table for +some reason (e.g. incorrect group descriptor checksum). + .TP .B test_fs Set a flag in the filesystem superblock indicating that it may be