| Message ID | 20180605154123.3226-1-josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 6/5/18 9:41 AM, Josef Bacik wrote: > Technically we should be able to get away with 0 as the > discard_alignment, but there's no way currently for the protocol to > indicate different alignments, and in real life most disks have > discard_alignment == discard_granularity. Just set our alignment to our > blocksize to make sure discards will actually work properly with 4k > drives. Applied, thanks.
Hi Josef, On Tue, Jun 05, 2018 at 11:41:23AM -0400, Josef Bacik wrote: > Technically we should be able to get away with 0 as the > discard_alignment, but there's no way currently for the protocol to > indicate different alignments, Actually there is, with the NBD_INFO_BLOCK_SIZE (and related) response(s) to the NBD_OPT_GO message during negotiation, but implementing that will probably require some more netlink messages. (some of this is still being hashed out on the NBD mailinglist; I'm sure your insights in that would be welcome)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index bdfbb2a7018c..ec9b43c9f7e3 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -238,6 +238,7 @@ static void nbd_size_update(struct nbd_device *nbd) if (config->flags & NBD_FLAG_SEND_TRIM) { nbd->disk->queue->limits.discard_granularity = config->blksize; + nbd->disk->queue->limits.discard_alignment = config->blksize; blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX); } blk_queue_logical_block_size(nbd->disk->queue, config->blksize); @@ -1055,6 +1056,7 @@ static void nbd_config_put(struct nbd_device *nbd) nbd->tag_set.timeout = 0; nbd->disk->queue->limits.discard_granularity = 0; + nbd->disk->queue->limits.discard_alignment = 0; blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX); blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue); @@ -1509,6 +1511,7 @@ static int nbd_dev_add(int index) blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue); blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue); disk->queue->limits.discard_granularity = 0; + disk->queue->limits.discard_alignment = 0; blk_queue_max_discard_sectors(disk->queue, 0); blk_queue_max_segment_size(disk->queue, UINT_MAX); blk_queue_max_segments(disk->queue, USHRT_MAX);
Technically we should be able to get away with 0 as the discard_alignment, but there's no way currently for the protocol to indicate different alignments, and in real life most disks have discard_alignment == discard_granularity. Just set our alignment to our blocksize to make sure discards will actually work properly with 4k drives. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- drivers/block/nbd.c | 3 +++ 1 file changed, 3 insertions(+)