From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:16128 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1756392AbbHZHVP (ORCPT ); Wed, 26 Aug 2015 03:21:15 -0400 Subject: Re: [PATCH v5] fstests: btrfs: Add reserved space leak check for rewrite dirty page To: Eryu Guan References: <1440119834-31504-1-git-send-email-quwenruo@cn.fujitsu.com> <20150826064146.GS17933@dhcp-13-216.nay.redhat.com> CC: , From: Qu Wenruo Message-ID: <55DD68E8.2020702@cn.fujitsu.com> Date: Wed, 26 Aug 2015 15:21:12 +0800 MIME-Version: 1.0 In-Reply-To: <20150826064146.GS17933@dhcp-13-216.nay.redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Eryu Guan wrote on 2015/08/26 14:41 +0800: > On Fri, Aug 21, 2015 at 09:17:14AM +0800, Qu Wenruo wrote: >> Btrfs qgroup reserve codes lacks check for rewrite dirty page, causing >> every write, even rewriting a uncommitted dirty page, to reserve space. >> >> But only written data will free the reserved space, causing reserved >> space leaking. >> >> The bug exists almost from the beginning of btrfs qgroup codes, but >> nobody found it. >> >> For example: >> >> 1)Write [0, 12K) into file A >> reserve 12K space >> >> File A: >> 0 4K 8K 12K >> |<--------dirty-------->| >> reserved: 12K >> >> 2)Write [0,4K) into file A >> 0 4K 8K 12K >> |<--------dirty-------->| >> reserved: 16K <<< Should be 12K >> >> 3) Commit transaction >> Dirty pages [0,12) written to disk. >> Free 12K reserved space. >> reserved: 4K <<< Should be 0 >> >> This testcase will test such problem. >> Kernel fix will need some huge change, so won't be soon. >> >> Signed-off-by: Qu Wenruo >> Reviewed-by: Filipe Manana >> --- >> Changelog: >> v2: >> Use smaller write size inside loop, in case commit is trigger by dirty >> page threshold, and ensure following write won't trigger EQUOT >> v3: >> Add more comments and fix some expression. >> v4: >> Rebase to latest fstests. >> v5: >> Use larger number to avoid conflicts with the test from Filipe Manana. >> --- >> tests/btrfs/099 | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++ >> tests/btrfs/099.out | 13 ++++++++ >> tests/btrfs/group | 1 + >> 3 files changed, 100 insertions(+) >> create mode 100755 tests/btrfs/099 >> create mode 100644 tests/btrfs/099.out >> >> diff --git a/tests/btrfs/099 b/tests/btrfs/099 >> new file mode 100755 >> index 0000000..ba531e1 >> --- /dev/null >> +++ b/tests/btrfs/099 >> @@ -0,0 +1,86 @@ >> +#! /bin/bash >> +# FS QA Test 099 >> +# >> +# Check for qgroup reserved space leaks caused by re-writing dirty ranges >> +# This bug has been present in btrfs qgroup for a long time >> +# >> +#----------------------------------------------------------------------- >> +# Copyright (c) 2015 Fujitsu. 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 $tmp.* >> +} >> + >> +# get standard environment, filters and checks >> +. ./common/rc >> +. ./common/filter >> + >> +# real QA test starts here >> + >> +_supported_fs btrfs >> +_supported_os Linux >> +_require_scratch >> +_need_to_be_root >> + >> +# Use big blocksize to ensure there is still enough space left for metadata >> +# space reserve. >> +BLOCKSIZE=$(( 2 * 1024 * 1024 )) # 2M block size >> +FILESIZE=$(( 128 * 1024 * 1024 )) # 128M file size >> + >> +_scratch_mkfs >> $seqres.full 2>&1 > > Just one minor issue here, please remove $seqres.full before test, > otherwise $seqres.full will keep growing. > > Thanks, > Eryu > Oh, you're right. I did forgot to remove it. BTW, is it better to add 'rm $seqres.full' to the template? Thanks, Qu