All of lore.kernel.org
 help / color / mirror / Atom feed
From: Eryu Guan <guan@eryu.me>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: guaneryu@gmail.com, wenli xie <wlxie7296@gmail.com>,
	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
Date: Mon, 15 Mar 2021 02:06:35 +0800	[thread overview]
Message-ID: <YE5Qq83n0Yki47yH@desktop> (raw)
In-Reply-To: <161526485320.1214319.14486851135232825638.stgit@magnolia>

On Mon, Mar 08, 2021 at 08:40:53PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> 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 <wlxie7296@gmail.com>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  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

  reply	other threads:[~2021-03-14 18:07 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-09  4:40 [PATCHSET 00/10] fstests: test kernel regressions fixed in 5.12 Darrick J. Wong
2021-03-09  4:40 ` [PATCH 01/10] xfs: test regression in xfs_bmap_validate_extent Darrick J. Wong
2021-03-09  4:40 ` [PATCH 02/10] generic: test reflink and copy_file_range behavior with O_SYNC and FS_XFLAG_SYNC files Darrick J. Wong
2021-03-09  4:40 ` [PATCH 03/10] xfs: test rtalloc alignment and math errors Darrick J. Wong
2021-03-11  7:58   ` Chandan Babu R
2021-03-23  4:15     ` Darrick J. Wong
2021-03-25  7:52       ` Chandan Babu R
2021-03-09  4:40 ` [PATCH 04/10] xfs: test mkfs min log size calculation w/ rt volumes Darrick J. Wong
2021-03-11  9:32   ` Chandan Babu R
2021-03-14 14:51   ` Eryu Guan
2021-03-14 16:39     ` Eryu Guan
2021-03-09  4:40 ` [PATCH 05/10] common/filter: refactor quota report filtering Darrick J. Wong
2021-03-11  9:42   ` Chandan Babu R
2021-03-09  4:40 ` [PATCH 06/10] xfs: test quota softlimit warning functionality Darrick J. Wong
2021-03-11 11:10   ` Chandan Babu R
2021-03-12  4:25     ` Chandan Babu R
2021-03-09  4:40 ` [PATCH 07/10] xfs/122: fix test for xfs_attr_shortform_t conversion Darrick J. Wong
2021-03-11 12:58   ` Christoph Hellwig
2021-03-09  4:40 ` [PATCH 08/10] generic: test file writers racing with FIDEDUPERANGE Darrick J. Wong
2021-03-12  7:13   ` Chandan Babu R
2021-03-09  4:40 ` [PATCH 09/10] generic: test a deadlock in xfs_rename when whiteing out files Darrick J. Wong
2021-03-14 18:06   ` Eryu Guan [this message]
2021-03-15 16:54     ` Darrick J. Wong
2021-03-09  4:40 ` [PATCH 10/10] xfs: test delalloc quota leak when chprojid fails Darrick J. Wong
2021-03-12  8:49   ` Chandan Babu R
2021-03-14 18:07 ` [PATCHSET 00/10] fstests: test kernel regressions fixed in 5.12 Eryu Guan
2021-03-14 21:36   ` Darrick J. Wong

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YE5Qq83n0Yki47yH@desktop \
    --to=guan@eryu.me \
    --cc=djwong@kernel.org \
    --cc=fstests@vger.kernel.org \
    --cc=guaneryu@gmail.com \
    --cc=linux-xfs@vger.kernel.org \
    --cc=wlxie7296@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.