From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93AC5C19F29 for ; Sat, 6 Aug 2022 04:03:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241558AbiHFEDG (ORCPT ); Sat, 6 Aug 2022 00:03:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241461AbiHFEDF (ORCPT ); Sat, 6 Aug 2022 00:03:05 -0400 Received: from out28-74.mail.aliyun.com (out28-74.mail.aliyun.com [115.124.28.74]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 643A214014; Fri, 5 Aug 2022 21:03:00 -0700 (PDT) X-Alimail-AntiSpam: AC=CONTINUE;BC=0.08715575|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_regular_dialog|0.154924-0.00444291-0.840633;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047201;MF=michael@allwinnertech.com;NM=1;PH=DS;RN=6;RT=6;SR=0;TI=SMTPD_---.OnDAFCd_1659758542; Received: from 192.168.220.136(mailfrom:michael@allwinnertech.com fp:SMTPD_---.OnDAFCd_1659758542) by smtp.aliyun-inc.com; Sat, 06 Aug 2022 12:02:25 +0800 Message-ID: Date: Sat, 6 Aug 2022 12:02:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH] ext4: fix error when itable blocks is greater than s_itb_per_group Content-Language: en-US To: Theodore Ts'o , Lukas Czerner Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, allwinner-opensource-support@allwinnertech.com References: <20220802021029.16046-1-michael@allwinnertech.com> <20220803071859.elywnni2yfol4bea@fedora> From: Michael Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 8/4/2022 10:19 AM, Theodore Ts'o wrote: > On Wed, Aug 03, 2022 at 09:18:59AM +0200, Lukas Czerner wrote: >> >> Hi Michael, >> >> mke2fs is making sure that we completely fill the inote table blocks. >> This is a corrupted image and so AFAICT ext4 is doing the right thing >> here. There does not seem to be a problem to fix, unless you can somehow >> trick mke2fs to make a file system like this. > > Several years ago, android was shipping a bogus/busted > reimeplementation of mke2fs, reportedly because a certain founder of > Android (cough, Andy Rubin, cough) was alergic to the GPL. ("The > problem with GPL in embedded systems [such as smartphones and tablets] > is that it's viral...") This bogus reimplementation would create file > systems where the number of inodes per block group was a multiple of 4 > instead of 8. But, it was under the BSD license, so it was all good! :-/ > > This bogus reimplementation of mkfs would, 50% of the time, create > busted file systems which couldn't be fixed, if they got corrupted, by > e2fsck. This is because e2fsprogs' allocation bitmap code assumes > that you can back the bitarray into a single contiguous memory block > --- and this doesn't work if the number of inodes per block group is > not a multiple of 8. If the file system got corrupted, the only > recourse was to wipe the user partition and the user would lose any > data that wasn't backed up to the cloud. > > This has since been fixed for quite some time, but if there is some > low-end Android manufacturer is using an ancient version of AOSP, this > could be happening even in 2022 --- but that doesn't mean we need to > support such broken file systems. As far as I'm concerned the only > way to make valid Android ext4 system images is the combination of > mke2fs and e2fsdroid, which is what modern versions of AOSP do. > > - Ted Dear Ted & Lukas, Thanks for your clarification. I did several tests, turned outs Ted was right. I'm clear now. -- Regards, Michael Wu