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[Qemu-devel] [PATCH 1/1] nbd: fix block-mirror NBD target
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH 1/1] nbd: fix block-mirror NBD target |
Date: |
Wed, 17 Feb 2016 18:08:11 +0300 |
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 <address@hidden>
CC: Paolo Bonzini <address@hidden>
---
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
- [Qemu-devel] [PATCH 1/1] nbd: fix block-mirror NBD target,
Denis V. Lunev <=