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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=unavailable 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 E7989C433DB for ; Sun, 14 Mar 2021 18:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1FD064E76 for ; Sun, 14 Mar 2021 18:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232662AbhCNSHK (ORCPT ); Sun, 14 Mar 2021 14:07:10 -0400 Received: from out20-38.mail.aliyun.com ([115.124.20.38]:47682 "EHLO out20-38.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231205AbhCNSGi (ORCPT ); Sun, 14 Mar 2021 14:06:38 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.07447457|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_system_inform|0.00837751-0.00358801-0.988034;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047187;MF=guan@eryu.me;NM=1;PH=DS;RN=5;RT=5;SR=0;TI=SMTPD_---.Jl-ALM3_1615745196; Received: from localhost(mailfrom:guan@eryu.me fp:SMTPD_---.Jl-ALM3_1615745196) by smtp.aliyun-inc.com(10.147.44.118); Mon, 15 Mar 2021 02:06:36 +0800 Date: Mon, 15 Mar 2021 02:06:35 +0800 From: Eryu Guan To: "Darrick J. Wong" Cc: guaneryu@gmail.com, wenli xie , linux-xfs@vger.kernel.org, fstests@vger.kernel.org Subject: Re: [PATCH 09/10] generic: test a deadlock in xfs_rename when whiteing out files Message-ID: References: <161526480371.1214319.3263690953532787783.stgit@magnolia> <161526485320.1214319.14486851135232825638.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <161526485320.1214319.14486851135232825638.stgit@magnolia> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Mar 08, 2021 at 08:40:53PM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong > > wenli xie reported a buffer cache deadlock when an overlayfs is mounted > atop xfs and overlayfs tries to replace a single-nlink file with a > whiteout file. This test reproduces that deadlock. > > Reported-by: wenli xie > Signed-off-by: Darrick J. Wong > --- > tests/generic/1300 | 109 ++++++++++++++++++++++++++++++++++++++++++++++++ > tests/generic/1300.out | 2 + > tests/generic/group | 1 > 3 files changed, 112 insertions(+) > create mode 100755 tests/generic/1300 > create mode 100644 tests/generic/1300.out > > > diff --git a/tests/generic/1300 b/tests/generic/1300 > new file mode 100755 > index 00000000..10df44e3 > --- /dev/null > +++ b/tests/generic/1300 > @@ -0,0 +1,109 @@ > +#! /bin/bash > +# SPDX-License-Identifier: GPL-2.0-or-later > +# Copyright (c) 2021 Oracle. All Rights Reserved. > +# > +# FS QA Test No. 1300 > +# > +# Reproducer for a deadlock in xfs_rename reported by Wenli Xie. > +# > +# When overlayfs is running on top of xfs and the user unlinks a file in the > +# overlay, overlayfs will create a whiteout inode and ask us to "rename" the > +# whiteout file atop the one being unlinked. If the file being unlinked loses > +# its one nlink, we then have to put the inode on the unlinked list. > +# > +# This requires us to grab the AGI buffer of the whiteout inode to take it > +# off the unlinked list (which is where whiteouts are created) and to grab > +# the AGI buffer of the file being deleted. If the whiteout was created in > +# a higher numbered AG than the file being deleted, we'll lock the AGIs in > +# the wrong order and deadlock. > +# > +# Note that this test doesn't do anything xfs-specific so it's a generic test. > +# This is a regression test for commit 6da1b4b1ab36 ("xfs: fix an ABBA deadlock > +# in xfs_rename"). > + > +seq=`basename $0` > +seqres=$RESULT_DIR/$seq > +echo "QA output created by $seq" > + > +here=`pwd` > +tmp=/tmp/$$ > +status=1 # failure is the default! > +trap "_cleanup; exit \$status" 0 1 2 3 15 > + > +_cleanup() > +{ > + stop_workers > + cd / > + rm -f $tmp.* > +} > + > +# get standard environment, filters and checks > +. ./common/rc > + > +# real QA test starts here > +_supported_fs generic > +_require_scratch > +test "$FSTYP" = "overlay" && _notrun "Test does not apply to overlayfs." > + > +modprobe -q overlay > +grep -q overlay /proc/filesystems || _notrun "Test requires overlayfs." We have _require_ext2() and _require_tmpfs(), I think it's time to refactor them into a new _require_filesystem() helper? > + > +rm -f $seqres.full > + > +_scratch_mkfs >> $seqres.full > +_scratch_mount Also, doing overlay mount requires the underlying to export d_type, perhaps we should do '_supports_filetype $SCRATCH_MNT' here, otherwise filesystems like nfs would fail the test. > + > +mkdir $SCRATCH_MNT/lowerdir > +mkdir $SCRATCH_MNT/lowerdir1 > +mkdir $SCRATCH_MNT/lowerdir/etc > +mkdir $SCRATCH_MNT/workers > +echo salts > $SCRATCH_MNT/lowerdir/etc/access.conf > +touch $SCRATCH_MNT/running > + > +stop_workers() { > + test -e $SCRATCH_MNT/running || return > + rm -f $SCRATCH_MNT/running > + > + while [ "$(ls $SCRATCH_MNT/workers/ | wc -l)" -gt 0 ]; do > + wait > + done > +} > + > +worker() { > + local tag="$1" > + local mergedir="$SCRATCH_MNT/merged$tag" > + local l="lowerdir=$SCRATCH_MNT/lowerdir:$SCRATCH_MNT/lowerdir1" > + local u="upperdir=$SCRATCH_MNT/upperdir$tag" > + local w="workdir=$SCRATCH_MNT/workdir$tag" > + local i="index=off,nfs_export=off" > + > + touch $SCRATCH_MNT/workers/$tag > + while test -e $SCRATCH_MNT/running; do > + rm -rf $SCRATCH_MNT/merged$tag > + rm -rf $SCRATCH_MNT/upperdir$tag > + rm -rf $SCRATCH_MNT/workdir$tag > + mkdir $SCRATCH_MNT/merged$tag > + mkdir $SCRATCH_MNT/workdir$tag > + mkdir $SCRATCH_MNT/upperdir$tag > + > + mount -t overlay overlay -o "$l,$u,$w,$i" $mergedir > + mv $mergedir/etc/access.conf $mergedir/etc/access.conf.bak > + touch $mergedir/etc/access.conf > + mv $mergedir/etc/access.conf $mergedir/etc/access.conf.bak > + touch $mergedir/etc/access.conf > + umount $mergedir > + done > + rm -f $SCRATCH_MNT/workers/$tag > +} > + > +for i in $(seq 0 $((4 + LOAD_FACTOR)) ); do > + worker $i & > +done > + > +sleep $((30 * TIME_FACTOR)) > +stop_workers > + > +echo Silence is golden. > +# success, all done > +status=0 > +exit > diff --git a/tests/generic/1300.out b/tests/generic/1300.out > new file mode 100644 > index 00000000..5805d30d > --- /dev/null > +++ b/tests/generic/1300.out > @@ -0,0 +1,2 @@ > +QA output created by 1300 > +Silence is golden. > diff --git a/tests/generic/group b/tests/generic/group > index 778aa8c4..2233a59d 100644 > --- a/tests/generic/group > +++ b/tests/generic/group > @@ -631,3 +631,4 @@ > 947 auto quick rw clone > 948 auto quick rw copy_range > 949 auto quick rw dedupe clone > +1300 auto rw overlay Also add 'rename' group? Thanks, Eryu