Commit 9776f0db authored by Edgar Kaziakhmedov's avatar Edgar Kaziakhmedov Committed by Eric Blake
Browse files

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: default avatarEdgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>
Message-Id: <20180118115158.17219-1-edgar.kaziakhmedov@virtuozzo.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 08fb10a7

block/nbd.c

+11 −0
Original line number Diff line number Diff line
@@ -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)