Re: [PATCH] btrfs: add a test for umount racing mount

[Josef Bacik <josef@toxicpanda.com>]

On 7/9/20 8:55 PM, Boris Burkov wrote:
> Test if dirtying many inodes, which delays the umount in `evict_inodes`,
> then umounting and quickly mounting again causes the mount to fail.
> 
> This race is fixed by the patch:
> "btrfs: fix mount failure caused by race with umount"
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
>   tests/btrfs/215     | 52 +++++++++++++++++++++++++++++++++++++++++++++
>   tests/btrfs/215.out |  2 ++
>   tests/btrfs/group   |  1 +
>   3 files changed, 55 insertions(+)
>   create mode 100755 tests/btrfs/215
>   create mode 100644 tests/btrfs/215.out
> 
> diff --git a/tests/btrfs/215 b/tests/btrfs/215
> new file mode 100755
> index 00000000..b142c2d6
> --- /dev/null
> +++ b/tests/btrfs/215
> @@ -0,0 +1,52 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 YOUR NAME HERE.  All Rights Reserved.

Facebook should go in "YOUR NAME HERE".

> +#
> +# FS QA Test 215
> +#
> +# Evicting dirty inodes can take a long time during umount.
> +# Check that a new mount racing with such a delayed umount succeeds.
> +#
> +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 generic

This isn't btrfs specific, so I'd put it in tests/generic/<whatever>

> +_supported_os Linux
> +_require_test
> +
> +_scratch_mkfs > /dev/null 2>&1
> +_scratch_mount
> +for i in $(seq 0 500)
> +	do
> +		  dd if=/dev/zero of="$SCRATCH_MNT/$i" bs=1M count=1 > /dev/null 2>&1
> +		  done
> +		  _scratch_unmount&
> +		  _scratch_mount
> +

Looks like your tabbing got carried away here, and add a space between 
_scratch_unmount and the &.

> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/215.out b/tests/btrfs/215.out
> new file mode 100644
> index 00000000..0a11773b
> --- /dev/null
> +++ b/tests/btrfs/215.out
> @@ -0,0 +1,2 @@
> +QA output created by 215
> +Silence is golden
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index 505665b5..dda0763e 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -217,3 +217,4 @@
>   212 auto balance dangerous
>   213 auto balance dangerous
>   214 auto quick send snapshot
> +215 auto quick

Spacing appears to be off here too.  Thanks,

Josef