From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:31173 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751294AbcHQI7X (ORCPT ); Wed, 17 Aug 2016 04:59:23 -0400 Subject: Re: [PATCH 1/2] btrfs/131: test for umount of read-only fs when quota rescan is paused To: Eryu Guan , Jeff Mahoney References: <2f102cc7-a6b2-e23d-9c56-de6c6bc5110d@suse.com> <20160817084539.GS27776@eguan.usersys.redhat.com> CC: linux-btrfs , From: Qu Wenruo Message-ID: Date: Wed, 17 Aug 2016 16:59:11 +0800 MIME-Version: 1.0 In-Reply-To: <20160817084539.GS27776@eguan.usersys.redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: At 08/17/2016 04:45 PM, Eryu Guan wrote: > On Tue, Aug 16, 2016 at 02:30:21PM -0400, Jeff Mahoney wrote: >> Ensure that we can unmount a read-only file system when quota rescan >> is paused from a previous read-write mount. >> >> If the kernel has a separate bug where we are returning early while >> waiting for the rescan worker, we can use that to un-hang the test, >> and report both errors. >> >> This issue is resolved by the following patch for the Linux kernel: >> "btrfs: properly track when rescan worker is running" >> >> Signed-off-by: Jeff Mahoney >> --- >> tests/btrfs/131 | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> tests/btrfs/131.out | 3 ++ >> tests/btrfs/group | 1 + >> 3 files changed, 104 insertions(+) >> create mode 100755 tests/btrfs/131 >> create mode 100644 tests/btrfs/131.out >> >> diff --git a/tests/btrfs/131 b/tests/btrfs/131 >> new file mode 100755 >> index 0000000..56c38a2 >> --- /dev/null >> +++ b/tests/btrfs/131 >> @@ -0,0 +1,100 @@ >> +#! /bin/bash >> +# FS QA Test 131 >> +# >> +# Test for bug where read-only mounts will hang on umount when >> +# a qgroup rescan was paused. This also tests whether that hung >> +# umount can be unhung by trying to make use of a separate bug that >> +# means we can interrupt the wait for the rescan worker. If that >> +# happens, we report both errors. >> +# >> +#----------------------------------------------------------------------- >> +# Copyright (c) 2016 SUSE. All Rights Reserved. >> +# >> +# This program is free software; you can redistribute it and/or >> +# modify it under the terms of the GNU General Public License as >> +# published by the Free Software Foundation. >> +# >> +# This program is distributed in the hope that it would be useful, >> +# but WITHOUT ANY WARRANTY; without even the implied warranty of >> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> +# GNU General Public License for more details. >> +# >> +# You should have received a copy of the GNU General Public License >> +# along with this program; if not, write the Free Software Foundation, >> +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA >> +#----------------------------------------------------------------------- >> +# >> + >> +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() >> +{ >> + cd / >> + rm -f $tmp.* >> +} >> + >> +# get standard environment, filters and checks >> +. ./common/rc >> +. ./common/filter >> + >> +# remove previous $seqres.full before test >> +rm -f $seqres.full >> + >> +# real QA test starts here >> + >> +# Modify as appropriate. >> +_supported_fs btrfs >> +_supported_os Linux >> + >> +# We'll exit with a quota rescan paused >> +_require_scratch_nocheck >> + >> +_require_btrfs >> +BTRFS_DEBUG_TREE_PROG="`set_prog_path btrfs-debug-tree`" >> +_require_command "$BTRFS_DEBUG_TREE_PROG" btrfs-debug-tree >> +TIMEOUT_PROG="`set_prog_path timeout`" >> +_require_command "$TIMEOUT_PROG" timeout > > The "set_prog_path" calls belong to common/config, we only need > "_require_command" calls in test. > >> + >> +rm -f $seqres.full >> +_scratch_mkfs >>$seqres.full 2>&1 >> + >> +_scratch_mount >> +cp -aR /lib/modules/$(uname -r) $SCRATCH_MNT > > Consider populating the filesystem using _populate_fs or fsstress? If only want to increase tree level, best solution is to create a lot of small 2K files. (Needs max_inline=2K incase user override it) _populate_fs with -s 2048 is for this case. If want normal files, -s 16384 would ensure it won't be inlined and still small enough for quick population. > >> + >> +# A qgroup rescan on an empty or small file system completes nearly >> +# immediately. We need to ensure that it runs long enough that it will >> +# be paused on umount. Snapshots slow down the rescan so we should see >> +# the race without a lot of data. This is an arbitrary number that >> +# works on a ramdisk so it should be sufficient for any storage. >> +for n in $(seq 1 100); do >> + _run_btrfs_util_prog subvolume snapshot $SCRATCH_MNT $SCRATCH_MNT/$n > > Use tab for indention. > >> +done >> +_run_btrfs_util_prog quota enable $SCRATCH_MNT >> +_scratch_unmount >> + >> +echo "read-write umount completed" >> + >> +# Confirm that the rescan is paused >> +if ! $BTRFS_DEBUG_TREE_PROG $SCRATCH_DEV | \ >> + egrep -q 'flags ON|SCANNING|INCONSISTENT scan'; then >> + echo "qgroup rescan not paused." >> +fi I'm a little concerned of this operation. As debug-tree output can change at any time, since it doesn't expect it to be used as a stable tool to exam some flag. Although I don't have a better alternative though. Thanks, Qu >> +_scratch_mount -r >> + >> +# If the bug exists, this will hang. If we can kill it, that's another bug. >> +$TIMEOUT_PROG 10 umount $SCRATCH_MNT >> +if test $? -eq 124 ; then >> + echo "umount hung but was killed" > > I see this log with 4.8-rc1 kernel, is that expected? > > Thanks, > Eryu > >> +fi >> +echo "read-only umount completed" >> + >> +# success, all done >> +status=0 >> +exit >> diff --git a/tests/btrfs/131.out b/tests/btrfs/131.out >> new file mode 100644 >> index 0000000..845a501 >> --- /dev/null >> +++ b/tests/btrfs/131.out >> @@ -0,0 +1,3 @@ >> +QA output created by 131 >> +read-write umount completed >> +read-only umount completed >> diff --git a/tests/btrfs/group b/tests/btrfs/group >> index 6b29c05..929fa21 100644 >> --- a/tests/btrfs/group >> +++ b/tests/btrfs/group >> @@ -133,3 +133,4 @@ >> 128 auto quick send >> 129 auto quick send >> 130 auto clone send >> +131 auto quick qgroup >> -- >> 1.8.5.6 >> >> >> -- >> Jeff Mahoney >> SUSE Labs >> -- >> To unsubscribe from this list: send the line "unsubscribe fstests" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >