From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262119AbTJNJ5q (ORCPT ); Tue, 14 Oct 2003 05:57:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262128AbTJNJ5q (ORCPT ); Tue, 14 Oct 2003 05:57:46 -0400 Received: from thebsh.namesys.com ([212.16.7.65]:45289 "HELO thebsh.namesys.com") by vger.kernel.org with SMTP id S262119AbTJNJ5o (ORCPT ); Tue, 14 Oct 2003 05:57:44 -0400 Message-ID: <3F8BC896.6020106@namesys.com> Date: Tue, 14 Oct 2003 13:57:42 +0400 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rogier Wolff CC: John Bradford , Wes Janzen , linux-kernel@vger.kernel.org Subject: Re: Why are bad disk sectors numbered strangely, and what happens to them? References: <32a101c3916c$e282e330$5cee4ca5@DIAMONDLX60> <200310131014.h9DAEwY3000241@81-2-122-30.bradfords.org.uk> <33a201c39174$2b936660$5cee4ca5@DIAMONDLX60> <20031014064925.GA12342@bitwizard.nl> <3F8BA037.9000705@sbcglobal.net> <200310140721.h9E7LmNE000682@81-2-122-30.bradfords.org.uk> <20031014074020.GC13117@bitwizard.nl> <200310140811.h9E8Bxq1000831@81-2-122-30.bradfords.org.uk> <3F8BB7AE.2040507@namesys.com> <20031014094629.GA16683@bitwizard.nl> In-Reply-To: <20031014094629.GA16683@bitwizard.nl> 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 Rogier Wolff wrote: >On Tue, Oct 14, 2003 at 12:45:34PM +0400, Hans Reiser wrote: > > >>Perhaps we should tell people to first write to the bad block, and only >>if the block remains bad after triggering the remapping by writing to it >>should you make any effort to get the filesystem to remap it for you. >>What do you think? >> >>Rogier has not indicated that he has tried writing to the bad sector, >>has he? >> >> > >Hans, > >I simply refuse to try to trigger a remapping by writing to the >sector. A couple of things can happen: > >1) The write succeeds on the "bad" spot. > > The "normal" write doesn't >do a "veriy-after-write", so the write might simply be succeeding, >resulting in an immediate data-loss (which might be masked if I try >to reread the data from userspace bacause the data is still cached!) > Do a hard reboot with > 25 seconds power off. > >2) the realloc might succeed, hiding the fact that my drive just lost >0.5k bytes of my data. I mean, there was SOME data there. Linux >wouldn't try to be reading it if it had never been written, right? A >drive that refers my data to /dev/null should be diverted there >itself. > >Of course, I left my drive that indicated it had problems (i.e. it >didn't spot the sector going bad before it became unreadable), in the >machine for another two days. It's getting replaced ASAP (i.e. the >next hour or so). > >The bad sector developed in a backup of data that is still running >hapilly on another machine. But I'm not risking a sector getting >assigned some important data going bad next time I notice something. > > Roger. > > > replacing the drive is reasonable caution. I think though that the other poster is right that IFF you want to remap bad blocks, the drive should do it not reiserfs. -- Hans