Re: [PATCH] fstests: test btrfs fsync after hole punching with no-holes mode

[Eryu Guan <guaneryu@gmail.com>]

On Mon, Mar 26, 2018 at 11:59:21PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> Test that when we have the no-holes mode enabled and a specific metadata
> layout, if we punch a hole and fsync the file, at replay time the whole
> hole was preserved.
> 
> This issue is fixed by the following btrfs patch for the linux kernel:
> 
>   "Btrfs: fix fsync after hole punching when using no-holes feature"

I'd expect a test failure with 4.16-rc6 kernel, as the mentioned fix
above is not there. But test always passes for me. Did I miss anything?
btrfs-progs version is btrfs-progs-4.11.1-3.fc27.

> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
>  tests/btrfs/159     | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/159.out |   5 +++
>  tests/btrfs/group   |   1 +
>  3 files changed, 106 insertions(+)
>  create mode 100755 tests/btrfs/159
>  create mode 100644 tests/btrfs/159.out
> 
> diff --git a/tests/btrfs/159 b/tests/btrfs/159
> new file mode 100755
> index 00000000..6083975a
> --- /dev/null
> +++ b/tests/btrfs/159
> @@ -0,0 +1,100 @@
> +#! /bin/bash
> +# FSQA Test No. 159
> +#
> +# Test that when we have the no-holes mode enabled and a specific metadata
> +# layout, if we punch a hole and fsync the file, at replay time the whole
> +# hole was preserved.
> +#
> +#-----------------------------------------------------------------------
> +#
> +# Copyright (C) 2018 SUSE Linux Products GmbH. All Rights Reserved.
> +# Author: Filipe Manana <fdmanana@suse.com>
> +#
> +# 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"
> +tmp=/tmp/$$
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	_cleanup_flakey
> +	cd /
> +	rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +. ./common/dmflakey
> +
> +# real QA test starts here
> +_supported_fs generic
                 ^^^^^^^ btrfs
> +_supported_os Linux
> +_require_scratch
> +_require_dm_target flakey
> +_require_xfs_io_command "fpunch"
> +
> +rm -f $seqres.full
> +
> +# We create the filesystem with a node size of 64Kb because we need to create a
> +# specific metadata layout in order to trigger the bug we are testing. At the
> +# moment the node size can not be smaller then the system's page size, so given
> +# that the largest possible page size is 64Kb and by default the node size is
> +# set to the system's page size value, we explictly create a filesystem with a
> +# 64Kb node size.
> +_scratch_mkfs -O no-holes -n $((64 * 1024)) >>$seqres.full 2>&1
> +_require_metadata_journaling $SCRATCH_DEV
> +_init_flakey
> +_mount_flakey
> +
> +# Create our test file with 831 extents of 256Kb each. Before each extent, there

I think it's 832 extents in total? As the index starts with 0.

Otherwise looks good to me.

Thanks,
Eryu

> +# is a 256Kb hole (except for the first extent, which starts at offset 0). This
> +# creates two leafs in the filesystem tree, with the extent at offset 216530944
> +# being the last item in the first leaf and the extent at offset 217055232 being
> +# the first item in the second leaf.
> +for ((i = 0; i <= 831; i++)); do
> +	offset=$((i * 2 * 256 * 1024))
> +	$XFS_IO_PROG -f -c "pwrite -S 0xab -b 256K $offset 256K" \
> +		$SCRATCH_MNT/foobar >/dev/null
> +done
> +
> +# Now persist everything done so far.
> +sync
> +
> +# Now punch a hole that covers part of the extent at offset 216530944.
> +$XFS_IO_PROG -c "fpunch $((216530944 + 128 * 1024 - 4000)) 256K" \
> +	     -c "fsync" \
> +	     $SCRATCH_MNT/foobar
> +
> +echo "File digest before power failure:"
> +md5sum $SCRATCH_MNT/foobar | _filter_scratch
> +
> +# Simulate a power failure and mount the filesystem to check that replaying the
> +# fsync log/journal succeeds and our test file has the expected content.
> +_flakey_drop_and_remount
> +
> +echo "File digest after power failure and log replay:"
> +md5sum $SCRATCH_MNT/foobar | _filter_scratch
> +
> +_unmount_flakey
> +_cleanup_flakey
> +
> +status=0
> +exit
> diff --git a/tests/btrfs/159.out b/tests/btrfs/159.out
> new file mode 100644
> index 00000000..3317e516
> --- /dev/null
> +++ b/tests/btrfs/159.out
> @@ -0,0 +1,5 @@
> +QA output created by 159
> +File digest before power failure:
> +c5c0a13588a639529c979c57c336f441  SCRATCH_MNT/foobar
> +File digest after power failure and log replay:
> +c5c0a13588a639529c979c57c336f441  SCRATCH_MNT/foobar
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index 8007e07e..ba766f6b 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -161,3 +161,4 @@
>  156 auto quick trim
>  157 auto quick raid
>  158 auto quick raid scrub
> +159 auto quick
> -- 
> 2.11.0
> 
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