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@xxxxxxxxxxxxx> > Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx> > --- > 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@xxxxxxxxxx> --D > return lo_fallocate(lo, rq, pos, > - (rq->cmd_flags & REQ_NOUNMAP) ? > - FALLOC_FL_ZERO_RANGE : > - FALLOC_FL_PUNCH_HOLE); > + write_zeroes_to_fallocate_mode(rq->cmd_flags)); > case REQ_OP_DISCARD: > return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE); > case REQ_OP_WRITE: > @@ -877,6 +884,7 @@ static void loop_config_discard(struct loop_device *lo) > q->limits.discard_alignment = 0; > blk_queue_max_discard_sectors(q, 0); > blk_queue_max_write_zeroes_sectors(q, 0); > + blk_queue_max_allocate_sectors(q, 0); > blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); > return; > } > @@ -886,6 +894,7 @@ static void loop_config_discard(struct loop_device *lo) > > blk_queue_max_discard_sectors(q, UINT_MAX >> 9); > blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); > + blk_queue_max_allocate_sectors(q, UINT_MAX >> 9); > blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); > } > > >