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authorIlya Dryomov <idryomov@gmail.com>2017-05-22 20:59:24 +0300
committerIlya Dryomov <idryomov@gmail.com>2017-05-29 12:18:01 +0300
commit6ac56951dc10232e24419f6972fc8131dd0166e0 (patch)
tree1a748b97e97439e897b30a26595c5a7872d131be /drivers/block/rbd.c
parent5ed02dbb497422bf225783f46e6eadd237d23d6b (diff)
downloadlinux-6ac56951dc10232e24419f6972fc8131dd0166e0.tar.xz
rbd: implement REQ_OP_WRITE_ZEROES
Commit 93c1defedcae ("rbd: remove the discard_zeroes_data flag") explicitly didn't implement REQ_OP_WRITE_ZEROES for rbd, while the following commit 48920ff2a5a9 ("block: remove the discard_zeroes_data flag") dropped ->discard_zeroes_data in favor of REQ_OP_WRITE_ZEROES. rbd does support efficient zeroing via CEPH_OSD_OP_ZERO opcode and will release either some or all blocks depending on whether the zeroing request is rbd_obj_bytes() aligned. This is how we currently implement discards, so REQ_OP_WRITE_ZEROES can be identical to REQ_OP_DISCARD for now. Caveats: - REQ_NOUNMAP is ignored, but AFAICT that's true of at least two other current implementations - nvme and loop - there is no ->write_zeroes_alignment and blk_bio_write_zeroes_split() is hence less helpful than blk_bio_discard_split(), but this can (and should) be fixed on the rbd side In the future we will split these into two code paths to respect REQ_NOUNMAP on zeroout and save on zeroing blocks that couldn't be released on discard. Fixes: 93c1defedcae ("rbd: remove the discard_zeroes_data flag") Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Jason Dillaman <dillaman@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/block/rbd.c')
-rw-r--r--drivers/block/rbd.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 454bf9c34882..c16f74547804 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4023,6 +4023,7 @@ static void rbd_queue_workfn(struct work_struct *work)
switch (req_op(rq)) {
case REQ_OP_DISCARD:
+ case REQ_OP_WRITE_ZEROES:
op_type = OBJ_OP_DISCARD;
break;
case REQ_OP_WRITE:
@@ -4420,6 +4421,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
q->limits.discard_granularity = segment_size;
q->limits.discard_alignment = segment_size;
blk_queue_max_discard_sectors(q, segment_size / SECTOR_SIZE);
+ blk_queue_max_write_zeroes_sectors(q, segment_size / SECTOR_SIZE);
if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;