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

Filipe Manana
2024-03-28T09:32:47Z

On Thu, Mar 28, 2024 at 9:19 AM Anand Jain <anand.jain@oracle.com> wrote:
>
> 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.

Yes, but as previously pointed out, the goal of the patch is just to
move repeated code into a helper function.
I would prefer such a change to be done separately.

Thanks.

>
> 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
>