| Message ID | 158157957565.111879.5952051034259419400.stgit@localhost.localdomain (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES | expand |
On 13.02.2020 21:11, Darrick J. Wong wrote: > On Thu, Feb 13, 2020 at 10:39:35AM +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@virtuozzo.com> >> Reviewed-by: Bob Liu <bob.liu@oracle.com> >> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> >> --- >> drivers/block/loop.c | 20 +++++++++++++------- >> 1 file changed, 13 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/block/loop.c b/drivers/block/loop.c >> index 739b372a5112..0704167a5aaa 100644 >> --- a/drivers/block/loop.c >> +++ b/drivers/block/loop.c >> @@ -581,6 +581,16 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, >> return 0; >> } >> > > Urgh, I meant "copy the comment directly to here", e.g. > > /* > * Convert REQ_OP_WRITE_ZEROES modifiers into fallocate mode > * > * If the caller requires allocation, select that mode. If the caller > * doesn't want deallocation, call zeroout to write zeroes the range. > * Otherwise, punch out the blocks. > */ > > The goal here is to reinforce the notion that FL_ZERO_RANGE is how we > achieve nounmap zeroing... The function is pretty small, and its meaning is easily seen from the name and description. I don't think we have to retell every function code line in a separate sentence, since this distract the attention from really difficult places, which are really need it. Kirill -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 739b372a5112..0704167a5aaa 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -581,6 +581,16 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, return 0; } +/* Convert REQ_OP_WRITE_ZEROES modifiers into fallocate mode */ +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); @@ -599,14 +609,8 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq) case REQ_OP_FLUSH: return lo_req_flush(lo, rq); case REQ_OP_WRITE_ZEROES: - /* - * If the caller doesn't want deallocation, call zeroout to - * write zeroes the range. Otherwise, punch them out. - */ 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 +881,7 @@ 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 +891,7 @@ 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); }