Re: [PATCH] btrfs: add test for enable/disable quota and create/destroy qgroup repeatedly

[Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

Hi Sidong,

I tried this patch and observed that it recreates the hang and confirms the fix.
Thanks. Here's my comments for improvements.

On Mar 01, 2022 / 15:19, Sidong Yang wrote:
> Test enabling/disable quota and creating/destroying qgroup repeatedly

nit: gerund (...ing) and base form are mixed. Base form would be the better to
be same as the code comment.

> in asynchronous and confirm it does not cause kernel hang. This is a
> regression test for the problem reported to linux-btrfs list [1].
> 
> The hang was recreated using the test case and fixed by kernel patch
> titled
> 
>   btrfs: qgroup: fix deadlock between rescan worker and remove qgroup
> 
> [1] https://lore.kernel.org/linux-btrfs/20220228014340.21309-1-realwakka@gmail.com/
> 
> Signed-off-by: Sidong Yang <realwakka@gmail.com>
> ---
>  tests/btrfs/262     | 54 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/262.out |  2 ++
>  2 files changed, 56 insertions(+)
>  create mode 100755 tests/btrfs/262
>  create mode 100644 tests/btrfs/262.out
> 
> diff --git a/tests/btrfs/262 b/tests/btrfs/262
> new file mode 100755
> index 00000000..9be380f9
> --- /dev/null
> +++ b/tests/btrfs/262
> @@ -0,0 +1,54 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2022 YOUR NAME HERE.  All Rights Reserved.

It's the better to put your name there :)

> +#
> +# FS QA Test 262
> +#
> +# Test the deadlock between qgroup and quota commands
> +#
> +. ./common/preamble
> +_begin_fstest auto qgroup
> +
> +# Import common functions.
> +. ./common/filter
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.

Can we remove this comment?

> +_supported_fs btrfs
> +
> +_require_scratch
> +
> +# Run command that enable/disable quota and create/destroy qgroup asynchronously
> +qgroup_deadlock_test()
> +{
> +	_scratch_mkfs > /dev/null 2>&1
> +	_scratch_mount
> +	echo "=== qgroup deadlock test ===" >> $seqres.full
> +
> +	pids=()
> +	for ((i = 0; i < 200; i++)); do
> +		$BTRFS_UTIL_PROG quota enable $SCRATCH_MNT 2>> $seqres.full &
> +		pids+=($!)
> +		$BTRFS_UTIL_PROG qgroup create 1/0 $SCRATCH_MNT 2>> $seqres.full &
> +		pids+=($!)
> +		$BTRFS_UTIL_PROG qgroup destroy 1/0 $SCRATCH_MNT 2>> $seqres.full &
> +		pids+=($!)
> +		$BTRFS_UTIL_PROG quota disable $SCRATCH_MNT 2>> $seqres.full &
> +		pids+=($!)		

Trailing tabs in the line above.

> +	done
> +
> +	for pid in "${pids[@]}"; do
> +		wait $pid
> +	done

I think simple "wait" command does what the for loop does.

> +
> +	_scratch_unmount
> +	_check_scratch_fs

I think _scratch_unmount and _check_scratch_fs are required only when
the test case repeats scratch mount and unmount. This test case looks
simple for me and the qgroup_deadlock_test function may not be necessary.

> +}
> +
> +qgroup_deadlock_test
> +
> +# success, all done
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/btrfs/262.out b/tests/btrfs/262.out
> new file mode 100644
> index 00000000..404badc3
> --- /dev/null
> +++ b/tests/btrfs/262.out
> @@ -0,0 +1,2 @@
> +QA output created by 262
> +Silence is golden
> -- 
> 2.25.1
> 

-- 
Best Regards,
Shin'ichiro Kawasaki