Am 08.09.2011 17:24, schrieb Paolo Bonzini:
> Map it to bdrv_discard. The server can now expose NBD_FLAG_SEND_TRIM.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> block/nbd.c | 31 +++++++++++++++++++++++++++++++
> nbd.c | 9 ++++++++-
> 2 files changed, 39 insertions(+), 1 deletions(-)
>
> diff --git a/block/nbd.c b/block/nbd.c
> index 5a7812c..964caa8 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -275,6 +275,36 @@ static int nbd_flush(BlockDriverState *bs)
> return 0;
> }
>
> +static int nbd_discard(BlockDriverState *bs, int64_t sector_num,
> + int nb_sectors)
> +{
> + BDRVNBDState *s = bs->opaque;
> + struct nbd_request request;
> + struct nbd_reply reply;
> +
> + if (!(s->nbdflags & NBD_FLAG_SEND_TRIM)) {
> + return 0;
> + }
> + request.type = NBD_CMD_TRIM;
> + request.handle = (uint64_t)(intptr_t)bs;
> + request.from = sector_num * 512;;
> + request.len = nb_sectors * 512;
> +
> + if (nbd_send_request(s->sock, &request) == -1)
> + return -errno;
> +
> + if (nbd_receive_reply(s->sock, &reply) == -1)
> + return -errno;
> +
> + if (reply.error !=0)
> + return -reply.error;
> +
> + if (reply.handle != request.handle)
> + return -EIO;
> +
> + return 0;
> +}
> +
> static void nbd_close(BlockDriverState *bs)
> {
> BDRVNBDState *s = bs->opaque;
> @@ -299,6 +329,7 @@ static BlockDriver bdrv_nbd = {
> .bdrv_write = nbd_write,
> .bdrv_close = nbd_close,
> .bdrv_flush = nbd_flush,
> + .bdrv_discard = nbd_discard,
> .bdrv_getlength = nbd_getlength,
> .protocol_name = "nbd",
> };
> diff --git a/nbd.c b/nbd.c
> index b65fb4a..f089904 100644
> --- a/nbd.c
> +++ b/nbd.c
> @@ -194,7 +194,7 @@ int nbd_negotiate(int csock, off_t size, uint32_t flags)
> cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
> cpu_to_be64w((uint64_t*)(buf + 16), size);
> cpu_to_be32w((uint32_t*)(buf + 24),
> - flags | NBD_FLAG_HAS_FLAGS |
> + flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
> NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
> memset(buf + 28, 0, 124);
>
> @@ -703,6 +703,13 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t
> size, uint64_t dev_offset,
> if (nbd_send_reply(csock, &reply) == -1)
> return -1;
> break;
> + case NBD_CMD_TRIM:
> + TRACE("Request type is TRIM");
> + bdrv_discard(bs, (request.from + dev_offset) / 512,
> + request.len / 512);
Errors are completely ignored? Does the NBD protocol not allow to return
an error?
Kevin
