Re: [PATCH v2] generic/446: make sure all background processes are dead before umount

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

On 2017/07/27 13:22, Eryu Guan wrote:
> Hi Xiao Yang,
>
> On Tue, Jul 25, 2017 at 04:04:21PM +0800, 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.
>>
>> 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
>> this point we're sure that there's no unfinished background process
>> blocking the umount.
>>
>> Signed-off-by: Eryu Guan<eguan@redhat.com>
>> ---
>> v2:
>> - move 'kill' to while loop condition to simplify the second loop
>> - add more comments about when to exit the loop
> Would you please help test&  review and provide reviewed-by tag if you
> think it's OK? Thanks a lot!
Hi Eryu,

I have tested it on my host,  so it's fine. :-)

Reviewed-by: Xiao Yang <yangx.jy@cn.fujitsu.com>

Thanks,
Xiao Yang
> Eryu
>
>>   tests/generic/446 | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/tests/generic/446 b/tests/generic/446
>> index 62ae449de6b1..6a1b69aa2edc 100755
>> --- a/tests/generic/446
>> +++ b/tests/generic/446
>> @@ -61,20 +61,20 @@ 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
>> +# loop until background dio read exits
>> +while kill -s 0 $dread_pid>/dev/null 2>&1; 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
>>   done
>>
>> -kill -9 $dread_pid>  /dev/null 2>&1
>>   wait $dread_pid>  /dev/null 2>&1
>>
>>   echo "Silence is golden"
>> -- 
>> 2.13.3
>>
>
> .
>