diff mbox series

[PULL,8/8] nbd: implement bdrv_get_info callback

Message ID 20180126160411.4033-9-eblake@redhat.com
State New
Headers show
Series [PULL,1/8] qapi: add name parameter to nbd-server-add | expand

Commit Message

Eric Blake Jan. 26, 2018, 4:04 p.m. UTC 
From: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>

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>
---
 block/nbd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
diff mbox series

Patch

diff --git a/block/nbd.c b/block/nbd.c
index 8b8ba56cdd0..94220f6d143 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)