diff options
| author | Eric Blake <eblake@redhat.com> | 2016-11-17 14:13:54 -0600 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-11-22 23:26:51 +0100 |
| commit | 169407e1f7c9afee1cdac0ee6ad0b8d5e361c4dd (patch) | |
| tree | b8c0eff97a23f1f62682faad9ccaee32cf28f564 /block/nbd-client.c | |
| parent | c2a85316902e67530da9d6548139fcce73c0cac6 (diff) | |
| download | qemu-169407e1f7c9afee1cdac0ee6ad0b8d5e361c4dd.tar.gz | |
nbd: Allow unmap and fua during write zeroes
Commit fa778fff wired up support to send the NBD_CMD_WRITE_ZEROES,
but forgot to inform the block layer that FUA unmapping of zeroes is
supported. Without BDRV_REQ_MAY_UNMAP listed as a supported flag,
the block layer will always insist on the NBD layer passing
NBD_CMD_FLAG_NO_HOLE, resulting in the server always allocating
things even when it was desired to let the server punch holes.
Similarly, failing to set BDRV_REQ_FUA means that the client may
send unnecessary NBD_CMD_FLUSH when it could have instead used the
NBD_CMD_FLAG_FUA bit.
CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1479413642-22463-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'block/nbd-client.c')
| -rw-r--r-- | block/nbd-client.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/block/nbd-client.c b/block/nbd-client.c index 2a302de674..3779c6c999 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -415,6 +415,10 @@ int nbd_client_init(BlockDriverState *bs, } if (client->nbdflags & NBD_FLAG_SEND_FUA) { bs->supported_write_flags = BDRV_REQ_FUA; + bs->supported_zero_flags |= BDRV_REQ_FUA; + } + if (client->nbdflags & NBD_FLAG_SEND_WRITE_ZEROES) { + bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; } qemu_co_mutex_init(&client->send_mutex); |