Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932745AbVITOLG (ORCPT ); Tue, 20 Sep 2005 10:11:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932752AbVITOLG (ORCPT ); Tue, 20 Sep 2005 10:11:06 -0400 Received: from [195.209.228.254] ([195.209.228.254]:49876 "EHLO shelob.oktetlabs.ru") by vger.kernel.org with ESMTP id S932745AbVITOLE convert rfc822-to-8bit (ORCPT ); Tue, 20 Sep 2005 10:11:04 -0400 Message-ID: <43301877.3040306@yandex.ru> Date: Tue, 20 Sep 2005 18:11:03 +0400 From: "Artem B. Bityutskiy" User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050513 Fedora/1.7.8-1.3.1 X-Accept-Language: en, ru, en-us MIME-Version: 1.0 To: =?ISO-8859-1?Q?J=F6rn_Engel?= Cc: Peter Menzebach , linux-kernel Subject: Re: data loss on jffs2 filesystem on dataflash References: <432812E8.2030807@mw-itcon.de> <432817FF.10307@yandex.ru> <4329251C.7050102@mw-itcon.de> <4329288B.8050909@yandex.ru> <43292AC6.40809@mw-itcon.de> <43292E16.70401@yandex.ru> <43292F91.9010302@mw-itcon.de> <432FE1EF.9000807@yandex.ru> <432FEF55.5090700@mw-itcon.de> <433006D8.4010502@yandex.ru> <20050920133244.GC4634@wohnheim.fh-wedel.de> In-Reply-To: <20050920133244.GC4634@wohnheim.fh-wedel.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1458 Lines: 41 J?rn Engel wrote: > Still can't. Block devices have the attribute that writing AAA... to > a block containing BBB... gives you one of three possible results in > case of power failure: > > 1. BBB...BBB all written > 2. AAA...AAA nothing written > 3. AAA...BBB partially written. > > Flash doesn't have 3, but two more cases: > 4. FFF...FFF erased, nothing written > 5. AAA...FFF erased, partially written > > Plus the really obnoxious > 6. FFF...FFF partially erased. Looks fine but some bits may flip > randomly, writes may not stick, etc. > > Now try finding a filesystem that is robust if 4-6 happens. ;) Don't underastand this. If you mean the atomicity, CRC may help here. And no problems. Or may be you missed the the fact that we have eraseblock size = writeblock size? >>JFFS2 orients to "classical" flashes. They have no "write page with >>built-in erase" operation. > What does this thing do? It erases individual page, then writes there. To put it differently, in your terminology, eraseblock size = writeblock size. P.S. I actually missed the mailing list, this should have gone to the MTD ML. So let's move there please. -- Best Regards, Artem B. Bityuckiy, St.-Petersburg, Russia. - 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/