[dm-devel] [PATCH v6 6/6] loop: Add support for REQ_ALLOCATE

[Kirill Tkhai]

On 12.02.2020 20:01, Darrick J. Wong wrote:
> On Mon, Feb 10, 2020 at 12:34:04PM +0300, Kirill Tkhai wrote:
>> Support for new modifier of REQ_OP_WRITE_ZEROES command.
>> This results in allocation extents in backing file instead
>> of actual blocks zeroing.
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> Reviewed-by: Bob Liu <bob.liu at oracle.com>
>> ---
>>  drivers/block/loop.c |   15 ++++++++++++---
>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
>> index 739b372a5112..bfe76d9adf09 100644
>> --- a/drivers/block/loop.c
>> +++ b/drivers/block/loop.c
>> @@ -581,6 +581,15 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
>>  	return 0;
>>  }
>>  
>> +static unsigned int write_zeroes_to_fallocate_mode(unsigned int flags)
>> +{
>> +	if (flags & REQ_ALLOCATE)
>> +		return 0;
>> +	if (flags & REQ_NOUNMAP)
>> +		return FALLOC_FL_ZERO_RANGE;
>> +	return FALLOC_FL_PUNCH_HOLE;
>> +}
>> +
>>  static int do_req_filebacked(struct loop_device *lo, struct request *rq)
>>  {
>>  	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
>> @@ -604,9 +613,7 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
>>  		 * write zeroes the range.  Otherwise, punch them out.
>>  		 */
> 
> Please update this comment to reflect the new REQ_ALLOCATE mode, and
> move it to where you define write_zeroes_to_fallocate_mode().
> 
> With that fixed,
> 
> Reviewed-by: Darrick J. Wong <darrick.wong at oracle.com>

Just to clarify. Is this "Reviewed-by:" tag for this patch or for the whole series?

Kirill