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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 971E0C433E0 for ; Fri, 12 Jun 2020 18:52:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74FBC2068E for ; Fri, 12 Jun 2020 18:52:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbgFLSwZ (ORCPT ); Fri, 12 Jun 2020 14:52:25 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:42526 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726085AbgFLSwY (ORCPT ); Fri, 12 Jun 2020 14:52:24 -0400 Received: from callcc.thunk.org (pool-100-0-195-244.bstnma.fios.verizon.net [100.0.195.244]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 05CIq7oI020942 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 12 Jun 2020 14:52:08 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id A15D042026D; Fri, 12 Jun 2020 14:52:07 -0400 (EDT) Date: Fri, 12 Jun 2020 14:52:07 -0400 From: "Theodore Y. Ts'o" To: Jan Kara Cc: "zhangyi (F)" , linux-ext4@vger.kernel.org, adilger.kernel@dilger.ca, zhangxiaoxu5@huawei.com Subject: Re: [PATCH v2] ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers Message-ID: <20200612185207.GB2863913@mit.edu> References: <20200609073540.3810702-1-yi.zhang@huawei.com> <20200609115026.GA12551@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200609115026.GA12551@quack2.suse.cz> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Jun 09, 2020 at 01:50:26PM +0200, Jan Kara wrote: > On Tue 09-06-20 15:35:40, zhangyi (F) wrote: > > In the ext4 filesystem with errors=panic, if one process is recording > > errno in the superblock when invoking jbd2_journal_abort() due to some > > error cases, it could be raced by another __ext4_abort() which is > > setting the SB_RDONLY flag but missing panic because errno has not been > > recorded. > > > > jbd2_journal_commit_transaction() > > jbd2_journal_abort() > > journal->j_flags |= JBD2_ABORT; > > jbd2_journal_update_sb_errno() > > | ext4_journal_check_start() > > | __ext4_abort() > > | sb->s_flags |= SB_RDONLY; > > | if (!JBD2_REC_ERR) > > | return; > > journal->j_flags |= JBD2_REC_ERR; > > > > Finally, it will no longer trigger panic because the filesystem has > > already been set read-only. Fix this by introduce j_abort_mutex to make > > sure journal abort is completed before panic, and remove JBD2_REC_ERR > > flag. > > > > Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock") > > Signed-off-by: zhangyi (F) > > Cc: > > Great, thanks! The patch looks good to me. You can add: > > Reviewed-by: Jan Kara Applied, thanks. - Ted