From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54523) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aW3iL-0005c1-VY for qemu-devel@nongnu.org; Wed, 17 Feb 2016 10:08:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aW3iH-00039B-VR for qemu-devel@nongnu.org; Wed, 17 Feb 2016 10:08:25 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:41981 helo=relay.sw.ru) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aW3iH-00037C-JG for qemu-devel@nongnu.org; Wed, 17 Feb 2016 10:08:21 -0500 From: "Denis V. Lunev" Date: Wed, 17 Feb 2016 18:08:11 +0300 Message-Id: <1455721691-14802-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH 1/1] nbd: fix block-mirror NBD target List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Denis V. Lunev" , qemu-devel@nongnu.org, Paolo Bonzini There is VM with 8 GB QCOW2 storage. Real size of the image file is 2 GB. 'drive-mirror' redirected to NBD target creates 8 GB image at destination. The situation is even worse as zeroes are sent through the channel. The patch simply adds .bdrv_co_write_zeroes callback to NBD block driver which works though NBD_TRIM to avoid transfer of zeroes. Signed-off-by: Denis V. Lunev CC: Paolo Bonzini --- block/nbd-client.c | 10 ++++++++++ block/nbd-client.h | 2 ++ block/nbd.c | 9 +++++++++ 3 files changed, 21 insertions(+) diff --git a/block/nbd-client.c b/block/nbd-client.c index 568c56c..ef0c5e8 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -344,7 +344,17 @@ int nbd_client_co_discard(BlockDriverState *bs, int64_t sector_num, } nbd_coroutine_end(client, &request); return -reply.error; +} + +int nbd_client_co_write_zeroes(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, BdrvRequestFlags flags) +{ + NbdClientSession *client = nbd_get_client_session(bs); + if (!(client->nbdflags & NBD_FLAG_SEND_TRIM)) { + return -ENOTSUP; + } + return nbd_client_co_discard(bs, sector_num, nb_sectors); } void nbd_client_detach_aio_context(BlockDriverState *bs) diff --git a/block/nbd-client.h b/block/nbd-client.h index e841340..aaef18d 100644 --- a/block/nbd-client.h +++ b/block/nbd-client.h @@ -40,6 +40,8 @@ void nbd_client_close(BlockDriverState *bs); int nbd_client_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); +int nbd_client_co_write_zeroes(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, BdrvRequestFlags flags); int nbd_client_co_flush(BlockDriverState *bs); int nbd_client_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); diff --git a/block/nbd.c b/block/nbd.c index 1a90bc7..8b05480 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -318,6 +318,13 @@ static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num, return nbd_client_co_discard(bs, sector_num, nb_sectors); } +static coroutine_fn int nbd_co_write_zeroes(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) +{ + return nbd_client_co_write_zeroes(bs, sector_num, nb_sectors, flags); +} + + static void nbd_close(BlockDriverState *bs) { nbd_client_close(bs); @@ -415,6 +422,7 @@ static BlockDriver bdrv_nbd_tcp = { .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, + .bdrv_co_write_zeroes = nbd_co_write_zeroes, .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, .bdrv_detach_aio_context = nbd_detach_aio_context, @@ -433,6 +441,7 @@ static BlockDriver bdrv_nbd_unix = { .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, + .bdrv_co_write_zeroes = nbd_co_write_zeroes, .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, .bdrv_detach_aio_context = nbd_detach_aio_context, -- 2.5.0