From 9776f0db6a19a0510e89b7aae38190b4811c95ba Mon Sep 17 00:00:00 2001 From: Edgar Kaziakhmedov Date: Thu, 18 Jan 2018 14:51:58 +0300 Subject: nbd: implement bdrv_get_info callback Since mirror job supports efficient zero out target mechanism (see in mirror_dirty_init()), implement bdrv_get_info to make it work over NBD. Such improvement will allow using the largest chunk possible and will decrease the number of NBD_CMD_WRITE_ZEROES requests on the wire. Signed-off-by: Edgar Kaziakhmedov Message-Id: <20180118115158.17219-1-edgar.kaziakhmedov@virtuozzo.com> Reviewed-by: Paolo Bonzini Signed-off-by: Eric Blake --- block/nbd.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'block/nbd.c') diff --git a/block/nbd.c b/block/nbd.c index 8b8ba56cdd..94220f6d14 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -566,6 +566,14 @@ static void nbd_refresh_filename(BlockDriverState *bs, QDict *options) bs->full_open_options = opts; } +static int nbd_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) +{ + if (bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP) { + bdi->can_write_zeroes_with_unmap = true; + } + return 0; +} + static BlockDriver bdrv_nbd = { .format_name = "nbd", .protocol_name = "nbd", @@ -583,6 +591,7 @@ static BlockDriver bdrv_nbd = { .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, + .bdrv_get_info = nbd_get_info, }; static BlockDriver bdrv_nbd_tcp = { @@ -602,6 +611,7 @@ static BlockDriver bdrv_nbd_tcp = { .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, + .bdrv_get_info = nbd_get_info, }; static BlockDriver bdrv_nbd_unix = { @@ -621,6 +631,7 @@ static BlockDriver bdrv_nbd_unix = { .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, + .bdrv_get_info = nbd_get_info, }; static void bdrv_nbd_init(void) -- cgit v1.2.1