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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 CAB6DC433DB for ; Mon, 8 Mar 2021 03:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 966D264DE5 for ; Mon, 8 Mar 2021 03:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233979AbhCHD4E (ORCPT ); Sun, 7 Mar 2021 22:56:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:44678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232535AbhCHD4D (ORCPT ); Sun, 7 Mar 2021 22:56:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id F3E8264DE5; Mon, 8 Mar 2021 03:56:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615175763; bh=+9yd+uVgQXOd0lh8eQNlG7LarQ3BnpuphGFZ2cAZl4w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UGyTN1jqYbdVUF9q2WIikgYMnMbmuPG6BbuL+FSrX54IeFtn3w+t2omhrI3mlyLYO z0EGwMxwQQiYWm5PiaLMrHc+RFCyNQYRpebeUCtcCelxcth3ScpUMWUXGpYi5EBLdY OORX72rIbnq7Um5dZDZj1KtLi5Dw9HpO7SbmnghXn0Lo3hIKOtgYwZWiBe7NyB7hfA VeRlckXFQvy/Y8SsMpGc6dHyhcg7cURFDXJjeLCpkVG7Gk2cJjXWaf0Dr16lYdJpay qM7BcptitS2PD7jsN7oe29ivLudKbQkWhtDvr8K/eSVYThWI2lEsbMjU0jaS+3qOE0 bq/OO9ZDW9JCw== Date: Sun, 7 Mar 2021 19:56:02 -0800 From: "Darrick J. Wong" To: Dave Chinner Cc: linux-xfs@vger.kernel.org, hch@lst.de, dchinner@redhat.com, christian.brauner@ubuntu.com Subject: Re: [PATCH v2.1 2/4] xfs: avoid buffer deadlocks when walking fs inodes Message-ID: <20210308035602.GK3419940@magnolia> References: <161514874040.698643.2749449122589431232.stgit@magnolia> <161514875165.698643.17020544838073213424.stgit@magnolia> <20210307203638.GJ3419940@magnolia> <20210307223703.GX4662@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210307223703.GX4662@dread.disaster.area> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Mar 08, 2021 at 09:37:03AM +1100, Dave Chinner wrote: > On Sun, Mar 07, 2021 at 12:36:38PM -0800, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > When we're servicing an INUMBERS or BULKSTAT request or running > > quotacheck, grab an empty transaction so that we can use its inherent > > recursive buffer locking abilities to detect inode btree cycles without > > hitting ABBA buffer deadlocks. > > > > Found by fuzzing an inode btree pointer to introduce a cycle into the > > tree (xfs/365). > > > > Signed-off-by: Darrick J. Wong > > --- > > v2.1: actually pass tp in the bulkstat_single case > > --- > > fs/xfs/xfs_itable.c | 42 +++++++++++++++++++++++++++++++++++++----- > > fs/xfs/xfs_iwalk.c | 32 +++++++++++++++++++++++++++----- > > 2 files changed, 64 insertions(+), 10 deletions(-) > > Looks ok, but I can't help but wonder if this case should flag > corruption if lock recursion does actually occur... Hm. Scrub will, since it checks the level and block number of every pointer it follows. IIRC the rest of the btree code isn't as paranoid about things like that. > Reviewed-by: Dave Chinner Anyway, thanks for the reviews. --D > -- > Dave Chinner > david@fromorbit.com