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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFC0EC33C9E for ; Fri, 17 Jan 2020 21:27:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B45E02072E for ; Fri, 17 Jan 2020 21:27:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729277AbgAQV1X (ORCPT ); Fri, 17 Jan 2020 16:27:23 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:58709 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729235AbgAQV1V (ORCPT ); Fri, 17 Jan 2020 16:27:21 -0500 Received: from callcc.thunk.org (guestnat-104-133-0-111.corp.google.com [104.133.0.111] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 00HLQvqE015166 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Jan 2020 16:26:59 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id AB7EF4207DF; Fri, 17 Jan 2020 16:26:57 -0500 (EST) Date: Fri, 17 Jan 2020 16:26:57 -0500 From: "Theodore Y. Ts'o" To: Jan Kara Cc: Kai Li , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com, gechangwei@live.cn, wang.yongd@h3c.com, wang.xibo@h3c.com Subject: Re: [PATCH] jbd2: clear JBD2_ABORT flag before journal_reset to update log tail info when load journal Message-ID: <20200117212657.GF448999@mit.edu> References: <20200111022542.5008-1-li.kai4@h3c.com> <20200114103119.GE6466@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200114103119.GE6466@quack2.suse.cz> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 14, 2020 at 11:31:19AM +0100, Jan Kara wrote: > Thanks for the patch! Just some small comments below: > > On Sat 11-01-20 10:25:42, Kai Li wrote: > > Fixes: 85e0c4e89c1b "jbd2: if the journal is aborted then don't allow update of the log tail" > > This tag should come at the bottom of the changelog (close to your > Signed-off-by). > > > If journal is dirty when mount, it will be replayed but jbd2 sb > > log tail cannot be updated to mark a new start because > > journal->j_flags has already been set with JBD2_ABORT first > > in journal_init_common. > > When a new transaction is committed, it will be recorded in block 1 > > first(journal->j_tail is set to 1 in journal_reset). If emergency > > restart again before journal super block is updated unfortunately, > > the new recorded trans will not be replayed in the next mount. > > It is danerous which may lead to metadata corruption for file system. > > I'd slightly rephrase the text here so that it is more easily readable and > correct some grammar mistakes. Something like: > > If the journal is dirty when the filesystem is mounted, jbd2 will replay > the journal but the journal superblock will not be updated by > journal_reset() because JBD2_ABORT flag is still set (it was set in > journal_init_common()). This is problematic because when a new transaction > is then committed, it will be recorded in block 1 (journal->j_tail was set > to 1 in journal_reset()). If unclean shutdown happens again before the > journal superblock is updated, the new recorded transaction will not be > replayed during the next mount (because of stale sb->s_start and > sb->s_sequence values) which can lead to filesystem corruption. > > Otherwise the patch looks good to me so feel free to add: > > Reviewed-by: Jan Kara > > (again this is added to the bottom of the changelog like the 'Fixes' tag or > 'Signed-off-by' tag). Thanks, applied with a fixed up commit description. - Ted