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authorEdgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>2018-01-18 14:51:58 +0300
committerEric Blake <eblake@redhat.com>2018-01-26 09:58:46 -0600
commit9776f0db6a19a0510e89b7aae38190b4811c95ba (patch)
treed8985aba7aa14f1c066f8e75b1d479cf833edacd
parent08fb10a7292637eb5836b8ac07b7ef8267db03be (diff)
downloadqemu-arm-9776f0db6a19a0510e89b7aae38190b4811c95ba.tar.gz
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 <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>
-rw-r--r--block/nbd.c11
1 files changed, 11 insertions, 0 deletions
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)