Re: [PATCH 05/10] btrfs: add helper to kill background process running _btrfs_stress_defrag

[Anand Jain <anand.jain@oracle.com>]

On 3/28/24 01:11, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> Killing a background process running _btrfs_stress_defrag() is not as
> simple as sending a signal to the process and waiting for it to die.
> Therefore we have the following logic to terminate such process:
> 
>         kill $pid
>         wait $pid
>         while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
>             sleep 1
>         done
> 
> Since this is repeated in several test cases, move this logic to a common
> helper and use it in all affected test cases. This will help to avoid
> repeating the same code again several times in upcoming changes.
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
>   common/btrfs    | 14 ++++++++++++++
>   tests/btrfs/062 |  7 +------
>   tests/btrfs/067 |  8 ++------
>   tests/btrfs/070 | 11 +++++------
>   tests/btrfs/072 |  7 +------
>   tests/btrfs/074 | 11 +++++------
>   6 files changed, 28 insertions(+), 30 deletions(-)
> 
> diff --git a/common/btrfs b/common/btrfs
> index d0adeea1..46056d4a 100644
> --- a/common/btrfs
> +++ b/common/btrfs
> @@ -383,6 +383,20 @@ _btrfs_stress_defrag()
>   	done
>   }
>   
> +# Kill a background process running _btrfs_stress_defrag()
> +_btrfs_kill_stress_defrag_pid()
> +{
> +       local defrag_pid=$1
> +
> +       # Ignore if process already died.
> +       kill $defrag_pid &> /dev/null
> +       wait $defrag_pid &> /dev/null
> +       # Wait for the defrag operation to finish.
> +       while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do

The same comments apply here regarding the use of pgrep.

Looks good.
Reviewed-by: Anand Jain <anand.jain@oracle.com>

Thanks, Anand

> +               sleep 1
> +       done
> +}
> +
>   # stress btrfs by remounting it with different compression algorithms in a loop
>   # run this with fsstress running at background could exercise the compression
>   # code path and ensure no race when switching compression algorithm with constant
> diff --git a/tests/btrfs/062 b/tests/btrfs/062
> index a2639d6c..59d581be 100755
> --- a/tests/btrfs/062
> +++ b/tests/btrfs/062
> @@ -53,12 +53,7 @@ run_test()
>   	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
>   	wait $fsstress_pid
>   	_btrfs_kill_stress_balance_pid $balance_pid
> -	kill $defrag_pid
> -	wait $defrag_pid
> -	# wait for the defrag operation to finish
> -	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
> -		sleep 1
> -	done
> +	_btrfs_kill_stress_defrag_pid $defrag_pid
>   
>   	echo "Scrub the filesystem" >>$seqres.full
>   	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
> diff --git a/tests/btrfs/067 b/tests/btrfs/067
> index 709db155..2bb00b87 100755
> --- a/tests/btrfs/067
> +++ b/tests/btrfs/067
> @@ -58,12 +58,8 @@ run_test()
>   	wait $fsstress_pid
>   
>   	touch $stop_file
> -	kill $defrag_pid
> -	wait
> -	# wait for btrfs defrag process to exit, otherwise it will block umount
> -	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
> -		sleep 1
> -	done
> +	wait $subvol_pid
> +	_btrfs_kill_stress_defrag_pid $defrag_pid
>   
>   	echo "Scrub the filesystem" >>$seqres.full
>   	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
> diff --git a/tests/btrfs/070 b/tests/btrfs/070
> index 54aa275c..cefa5723 100755
> --- a/tests/btrfs/070
> +++ b/tests/btrfs/070
> @@ -60,17 +60,16 @@ run_test()
>   
>   	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
>   	wait $fsstress_pid
> -	kill $replace_pid $defrag_pid
> -	wait
> +	kill $replace_pid
> +	wait $replace_pid
>   
> -	# wait for the defrag and replace operations to finish
> -	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
> -		sleep 1
> -	done
> +	# wait for the replace operation to finish
>   	while ps aux | grep "replace start" | grep -qv grep; do
>   		sleep 1
>   	done
>   
> +	_btrfs_kill_stress_defrag_pid $defrag_pid
> +
>   	echo "Scrub the filesystem" >>$seqres.full
>   	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
>   	if [ $? -ne 0 ]; then
> diff --git a/tests/btrfs/072 b/tests/btrfs/072
> index 6c15b51f..505d0b57 100755
> --- a/tests/btrfs/072
> +++ b/tests/btrfs/072
> @@ -52,13 +52,8 @@ run_test()
>   
>   	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
>   	wait $fsstress_pid
> -	kill $defrag_pid
> -	wait $defrag_pid
> -	# wait for the defrag operation to finish
> -	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
> -		sleep 1
> -	done
>   
> +	_btrfs_kill_stress_defrag_pid $defrag_pid
>   	_btrfs_kill_stress_scrub_pid $scrub_pid
>   
>   	echo "Scrub the filesystem" >>$seqres.full
> diff --git a/tests/btrfs/074 b/tests/btrfs/074
> index 9b22c620..d51922d0 100755
> --- a/tests/btrfs/074
> +++ b/tests/btrfs/074
> @@ -52,16 +52,15 @@ run_test()
>   
>   	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
>   	wait $fsstress_pid
> -	kill $defrag_pid $remount_pid
> -	wait
> -	# wait for the defrag and remount operations to finish
> -	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
> -		sleep 1
> -	done
> +	kill $remount_pid
> +	wait $remount_pid
> +	# wait for the remount operation to finish
>   	while ps aux | grep "mount.*$SCRATCH_MNT" | grep -qv grep; do
>   		sleep 1
>   	done
>   
> +	_btrfs_kill_stress_defrag_pid $defrag_pid
> +
>   	echo "Scrub the filesystem" >>$seqres.full
>   	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
>   	if [ $? -ne 0 ]; then