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nbd: implement bdrv_get_info callback

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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 <edgar.kaziakhmedov@virtuozzo.com>
Message-Id: <20180118115158.17219-1-edgar.kaziakhmedov@virtuozzo.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Edgar Kaziakhmedov 2018-01-18 14:51:58 +03:00 • committed by Eric Blake
parent 08fb10a729
commit 9776f0db6a
1 changed files with 11 additions and 0 deletions
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11
block/nbd.c
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@ -566,6 +566,14 @@ static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
bs->full_open_options = opts; 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 = { static BlockDriver bdrv_nbd = {
.format_name = "nbd", .format_name = "nbd",
.protocol_name = "nbd", .protocol_name = "nbd",
@ -583,6 +591,7 @@ static BlockDriver bdrv_nbd = {
.bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename, .bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_get_info = nbd_get_info,
}; };
static BlockDriver bdrv_nbd_tcp = { static BlockDriver bdrv_nbd_tcp = {
@ -602,6 +611,7 @@ static BlockDriver bdrv_nbd_tcp = {
.bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename, .bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_get_info = nbd_get_info,
}; };
static BlockDriver bdrv_nbd_unix = { static BlockDriver bdrv_nbd_unix = {
@ -621,6 +631,7 @@ static BlockDriver bdrv_nbd_unix = {
.bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_detach_aio_context = nbd_detach_aio_context,
.bdrv_attach_aio_context = nbd_attach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context,
.bdrv_refresh_filename = nbd_refresh_filename, .bdrv_refresh_filename = nbd_refresh_filename,
.bdrv_get_info = nbd_get_info,
}; };
static void bdrv_nbd_init(void) static void bdrv_nbd_init(void)