Re: [PATCH] generic: test Btrfs delalloc accounting overflow

[Nikolay Borisov <nborisov@suse.com>]

On  2.06.2017 11:23, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> This is a regression test for "[PATCH] Btrfs: fix delalloc accounting
> leak caused by u32 overflow". It creates a bunch of delalloc extents and
> merges them together to make sure the accounting is done right.
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  tests/generic/438     | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/438.out |  2 ++
>  tests/generic/group   |  1 +
>  3 files changed, 80 insertions(+)
>  create mode 100755 tests/generic/438
>  create mode 100644 tests/generic/438.out
> 
> diff --git a/tests/generic/438 b/tests/generic/438
> new file mode 100755
> index 00000000..8edac03d
> --- /dev/null
> +++ b/tests/generic/438
> @@ -0,0 +1,77 @@
> +#! /bin/bash
> +# FS QA Test 438
> +#
> +# Test delayed allocation with a large number of extents that are merged.
> +# Regression test for patch "Btrfs: fix delalloc accounting leak caused by u32
> +# overflow".
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2017 Facebook.  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
> +
> +test_file="$TEST_DIR/$seq"
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.* "$test_file"
> +}
> +
> +. ./common/rc
> +. ./common/filter
> +
> +rm -f $seqres.full
> +
> +_supported_fs generic
> +_supported_os Linux
> +_require_test
> +
> +# Create 32k extents. All of these extents will be accounted as outstanding and
> +# reserved.
> +for ((i = 0; i < 32 * 1024; i++)); do
> +	xfs_io -f -c "pwrite $((2 * 4096 * i)) 4096" "$test_file" >>"$seqres.full"
> +done
> +
> +# Fill in the gaps between the created extents. The outstanding extents will
> +# all be merged into 1, but there will still be 32k reserved.
> +for ((i = 0; i < 32 * 1024; i++)); do
> +	xfs_io -f -c "pwrite $((2 * 4096 * i + 1)) 4096" "$test_file" >>"$seqres.full"
> +done
> +
> +# Flush the delayed allocations.
> +sync
> +
> +# Make sure that we didn't leak any metadata space.
> +if [[ $FSTYP = btrfs ]]; then
> +	uuid="$(findmnt -n -o UUID "$TEST_DIR")"

if we are on btrfs and we don't have findmnt this test will likely fail.
Perhaps include a _require_command findmnt

> +	cd "/sys/fs/btrfs/$uuid/allocation"
> +	echo "$(($(cat metadata/bytes_may_use) - $(cat global_rsv_reserved))) bytes leaked" | grep -v '^0 '
> +fi
> +
> +echo "Silence is golden"
> +
> +status=0
> +exit
> diff --git a/tests/generic/438.out b/tests/generic/438.out
> new file mode 100644
> index 00000000..4968f4d7
> --- /dev/null
> +++ b/tests/generic/438.out
> @@ -0,0 +1,2 @@
> +QA output created by 438
> +Silence is golden
> diff --git a/tests/generic/group b/tests/generic/group
> index 438c2990..c804b05d 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -440,3 +440,4 @@
>  435 auto encrypt
>  436 auto quick rw
>  437 auto quick
> +438 auto
>