Re: [PATCH] generic/446: make sure all background processes are dead before umount

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2017/07/24 18:11, Eryu Guan wrote:
> The $dread_pid refers to the while-true-do loop, wait for $dread_pid
> doesn't mean the xfs_io direct read process is already dead,
> sometimes xfs_io process is still running and blocking
> _scratch_unmount.
Hi Eryu,

Could you tell me what can i do to trigger this block?
> Fix it by making the direct read does a fixed number of loop and
> break out the second mmap-fpunch loop if the first loop exits. At

Does it break out the second mmap-fpunch loop if the first loop doesn't
exit?

> this point we're sure that there's no unfinished background process
> blocking the umount.

The others look fine.

Thanks,
Xiao Yang.
> Signed-off-by: Eryu Guan <eguan@redhat.com>
> ---
>  tests/generic/446 | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/tests/generic/446 b/tests/generic/446
> index 62ae449de6b1..83ff4ac9edd3 100755
> --- a/tests/generic/446
> +++ b/tests/generic/446
> @@ -61,20 +61,22 @@ filesz=$((65536 * 2))
>  $XFS_IO_PROG -f -c "truncate $((filesz * 2))" $SCRATCH_MNT/file >> $seqres.full
>  
>  # run a background dio read to a hole in a loop
> -while true; do
> +for i in `seq 0 999`; do
>  	$XFS_IO_PROG -d -c "pread 0 $filesz" $SCRATCH_MNT/file > /dev/null 2>&1
>  done &
>  
>  dread_pid=$!
>  
>  # run mapped write to the same hole as dio read
> -for i in `seq 0 999`; do
> +while true; do
>  	$XFS_IO_PROG -c "mmap 0 $filesz" -c "mwrite 0 $filesz" $SCRATCH_MNT/file \
>  		> /dev/null
>  	$XFS_IO_PROG -c "fpunch 0 $filesz" $SCRATCH_MNT/file > /dev/null
> +	if ! kill -s 0 $dread_pid >/dev/null 2>&1; then
> +		break
> +	fi
>  done
>  
> -kill -9 $dread_pid > /dev/null 2>&1
>  wait $dread_pid > /dev/null 2>&1
>  
>  echo "Silence is golden"