From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964824AbXCSVN0 (ORCPT ); Mon, 19 Mar 2007 17:13:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932869AbXCSVN0 (ORCPT ); Mon, 19 Mar 2007 17:13:26 -0400 Received: from smtp.nokia.com ([131.228.20.172]:25629 "EHLO mgw-ext13.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932705AbXCSVNY convert rfc822-to-8bit (ORCPT ); Mon, 19 Mar 2007 17:13:24 -0400 Subject: Re: [PATCH 00/22 take 3] UBI: Unsorted Block Images From: Artem Bityutskiy Reply-To: dedekind@infradead.org To: Matt Mackall Cc: Josh Boyer , Linux Kernel Mailing List , Frank Haverkamp , Christoph Hellwig , David Woodhouse In-Reply-To: <20070319195442.GT4892@waste.org> References: <20070314151934.1112.70126.sendpatchset@localhost.localdomain> <20070318162720.GI10459@waste.org> <1174236579.17249.6.camel@sauron> <20070318191812.GM4892@waste.org> <20070318203149.GC29295@crusty.rchland.ibm.com> <20070319170838.GP4892@waste.org> <1174328188.30079.46.camel@zod.rchland.ibm.com> <20070319195442.GT4892@waste.org> Content-Type: text/plain; charset=utf-8 Date: Mon, 19 Mar 2007 23:06:33 +0200 Message-Id: <1174338393.17249.53.camel@sauron> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-1.fc6) Content-Transfer-Encoding: 8BIT X-OriginalArrivalTime: 19 Mar 2007 21:06:33.0833 (UTC) FILETIME=[79596D90:01C76A6A] X-eXpurgate-Category: 1/0 X-eXpurgate-ID: 149371::070319230637-0B0DFBB0-2D7EA9F6/0-0/0-1 X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2007-03-19 at 14:54 -0500, Matt Mackall wrote: > The issue is 14000 lines of patch to make a parallel subsystem. Parallel system exists since very long. One is flash->SW_or_HW_FTL->all_blkdev_stuff. The other is MTD->JFFS2. Think about _why_ there are 2 of them. Hint - reliability, performance. Your ranting basically says that only the first one makes sense. This is not true. We enhance the second branch, not the first, please, realize this. Both branches have their user base, and have always had. > iSCSI/nbd(6) > | > filesystem { swap | ext3 ext3 jffs2 > \ | | | / > / \ | dm-crypt->snapshot(5) / > device mapper -| \ \ | / > | partitioning / > | | partitioning(4) > | wear leveling(3) / > | | / > | block concatenation > | | | | | > \ bad block remapping(2) > | | | | > MTD raw block { raw block devices with no smarts(1) > / | \ \ > hardware { NAND NAND NAND NAND Matt, as I pointed in the first mail, flash != block device. In your picture I see NAND->MTD raw block. So am I right that you assume that we already have a decent FTL? The fact is that we do not. Please, bear in mind that decent FTL is difficult and an FS on top of FTL is slow, FTL hits performance considerably. -- Best regards, Artem Bityutskiy (Битюцкий Артём)