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 <quwenruo@xxxxxxxxxxxxxx> Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx> --- 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>&1Just 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 -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
