Re: [PATCH] fstests: btrfs/179 call quota rescan

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

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On 2020/2/7 下午8:01, Anand Jain wrote:
> On some systems btrfs/179 fails as the check finds that there is
> difference in the qgroup counts.
> 
> By the async nature of qgroup tree scan, the latest qgroup counts at the
> time of umount might not be upto date,

Yes, so far so good.

> if it isn't then the check will
> report the difference in count. The difference in qgroup counts are anyway
> updated in the following mount, so it is not a real issue that this test
> case is trying to verify.

No problem either.

> So make sure the qgroup counts are updated
> before unmount happens and make the check happy.

But the solution doesn't look correct to me.

We should either make btrfs-check to handle such half-dropped case
better, or find a way to wait for all subvolume drop to be finished in
test case.

Papering the test by rescan is not a good idea at all.
If one day we really hit some qgroup accounting problem, this papering
way could hugely reduce the coverage.

Thanks,
Qu

> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  tests/btrfs/179 | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tests/btrfs/179 b/tests/btrfs/179
> index 4a24ea419a7e..74e91841eaa6 100755
> --- a/tests/btrfs/179
> +++ b/tests/btrfs/179
> @@ -109,6 +109,14 @@ wait $snapshot_pid
>  kill $delete_pid
>  wait $delete_pid
>  
> +# By the async nature of qgroup tree scan, the latest qgroup counts at the time
> +# of umount might not be upto date, if it isn't then the check will report the
> +# difference in count. The difference in qgroup counts are anyway updated in the
> +# following mount, so it is not a real issue that this test case is trying to
> +# verify. So make sure the qgroup counts are updated before unmount happens.
> +
> +$BTRFS_UTIL_PROG quota rescan -w $SCRATCH_MNT >> $seqres.full
> +
>  # success, all done
>  echo "Silence is golden"
>  
> 


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