Re: [PATCH] Fstest: btrfs/151: test if device delete ends up with losing raid profile

[Eryu Guan <eguan@redhat.com>]

On Mon, Oct 09, 2017 at 11:39:21AM -0600, Liu Bo wrote:
> Currently running 'btrfs device delete' can end up with losing data raid
> profile (if any), this test is to reproduce the problem.
> 
> The fix is
>      "Btrfs: avoid losing data raid profile when deleting a device"
> 
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
>  tests/btrfs/151     | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/151.out |  2 ++
>  tests/btrfs/group   |  1 +
>  3 files changed, 76 insertions(+)
>  create mode 100755 tests/btrfs/151
>  create mode 100644 tests/btrfs/151.out
> 
> diff --git a/tests/btrfs/151 b/tests/btrfs/151
> new file mode 100755
> index 0000000..1866cb6
> --- /dev/null
> +++ b/tests/btrfs/151
> @@ -0,0 +1,73 @@
> +#! /bin/bash
> +# FS QA Test 151
> +#
> +# Test if it's losing data chunk's raid profile after 'btrfs device
> +# remove'.
> +#
> +# The fix is
> +#	Btrfs: avoid losing data raid profile when deleting a device
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2017 Oracle.  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
> +_require_scratch

Better to have _require_btrfs_dev_del_by_devid too.

> +_require_scratch_dev_pool 3

Hmm, this only reproduces for me if I have exact three devices in
SCRATCH_DEV_POOL, large dev pool passed the test. If this can only be
reproduced with a three-device setup, I think we need to limit the dev
pool size to at most 3, e.g.

# <comments about why we need exact 3 devices>
_scratch_dev_pool_get 3
<do test here>
_scratch_dev_pool_put
status=0
exit

> +
> +# create raid1 for data
> +_scratch_pool_mkfs "-d raid1 -b 1G" >> $seqres.full 2>&1
> +
> +# we need an empty data chunk, so nospace_cache is required.
> +_scratch_mount -onospace_cache
> +
> +# if data chunk is empty, 'btrfs device remove' can change raid1 to
> +# single.
> +$BTRFS_UTIL_PROG device delete 2 $SCRATCH_MNT >> $seqres.full
> +
> +df_ret=`$BTRFS_UTIL_PROG filesystem df $SCRATCH_MNT`
> +echo $df_ret | $AWK_PROG -F ':' '/Data,/ {print $1}'

I'd like to avoid saving outputs in a variable, it's easy to cause
subtle problems without proper quoting, as Dave found out in this thread

[whacky issue] xfs/277 endlessly looping in _require_xfs_io_command
http://www.spinics.net/lists/fstests/msg07501.html

How about:

# save btrfs filesystem df output for debug purpose
$BTRFS_UTIL_PROG filesystem df $SCRATCH_MNT >>$seqres.full 2>&1
$BTRFS_UTIL_PROG filesystem df $SCRATCH_MNT | \
	$AWK_PROG -F ':' '/Data,/ {print $1}'

Thanks,
Eryu

> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/151.out b/tests/btrfs/151.out
> new file mode 100644
> index 0000000..0a1de06
> --- /dev/null
> +++ b/tests/btrfs/151.out
> @@ -0,0 +1,2 @@
> +QA output created by 151
> +Data, RAID1
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index e73bb1b..a7ff7b0 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -153,3 +153,4 @@
>  148 auto quick rw
>  149 auto quick send compress
>  150 auto quick dangerous
> +151 auto quick
> -- 
> 2.5.0
> 
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