Re: [Qemu-devel] [PATCH COLO v4 08/15] NBD client: implement block driver interfaces to connect/disconnect NBD server

[Gonglei <arei.gonglei@huawei.com>]

On 2015/5/8 17:16, Wen Congyang wrote:
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
>  block/nbd.c | 65 ++++++++++++++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 47 insertions(+), 18 deletions(-)
> 
> diff --git a/block/nbd.c b/block/nbd.c
> index 2176186..0624232 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -44,6 +44,8 @@
>  typedef struct BDRVNBDState {
>      NbdClientSession client;
>      QemuOpts *socket_opts;
> +    char *export;
> +    bool connected;
>  } BDRVNBDState;
>  
>  static int nbd_parse_uri(const char *filename, QDict *options)
> @@ -254,34 +256,55 @@ static int nbd_establish_connection(BlockDriverState *bs, Error **errp)
>      return sock;
>  }
>  
> -static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
> -                    Error **errp)
> +static void nbd_connect_server(BlockDriverState *bs, Error **errp)
>  {
>      BDRVNBDState *s = bs->opaque;
> -    char *export = NULL;
> -    int result, sock;
> -    Error *local_err = NULL;
> -
> -    /* Pop the config into our state object. Exit if invalid. */
> -    nbd_config(s, options, &export, &local_err);
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> -        return -EINVAL;
> -    }
> +    int sock;
>  
>      /* establish TCP connection, return error if it fails
>       * TODO: Configurable retry-until-timeout behaviour.
>       */
>      sock = nbd_establish_connection(bs, errp);
>      if (sock < 0) {
> -        g_free(export);
> -        return sock;
> +        return;
>      }
>  
>      /* NBD handshake */
> -    result = nbd_client_init(bs, sock, export, errp);
> -    g_free(export);
> -    return result;
> +    nbd_client_init(bs, sock, s->export, errp);
> +
> +    s->connected = true;
> +}
> +
> +static void nbd_disconnect_server(BlockDriverState *bs)
> +{
> +    BDRVNBDState *s = bs->opaque;
> +
> +    if (s->connected) {
> +        nbd_client_close(bs);
> +        s->connected = false;
> +    }
> +}
> +
> +static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
> +                    Error **errp)
> +{
> +    BDRVNBDState *s = bs->opaque;
> +    Error *local_err = NULL;
> +
> +    /* Pop the config into our state object. Exit if invalid. */
> +    nbd_config(s, options, &s->export, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return -EINVAL;
> +    }
> +
> +    nbd_connect_server(bs, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return -EINVAL;
> +    }
> +
> +    return 0;
>  }
>  
>  static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
> @@ -318,7 +341,7 @@ static void nbd_close(BlockDriverState *bs)
>      BDRVNBDState *s = bs->opaque;
>  
>      qemu_opts_del(s->socket_opts);
> -    nbd_client_close(bs);
> +    nbd_disconnect_server(bs);

We should free s->export here, right?

Regards,
-Gonglei

>  }
>  
>  static int64_t nbd_getlength(BlockDriverState *bs)
> @@ -400,6 +423,8 @@ 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_connect               = nbd_connect_server,
> +    .bdrv_disconnect            = nbd_disconnect_server,
>  };
>  
>  static BlockDriver bdrv_nbd_tcp = {
> @@ -418,6 +443,8 @@ 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_connect               = nbd_connect_server,
> +    .bdrv_disconnect            = nbd_disconnect_server,
>  };
>  
>  static BlockDriver bdrv_nbd_unix = {
> @@ -436,6 +463,8 @@ 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_connect               = nbd_connect_server,
> +    .bdrv_disconnect            = nbd_disconnect_server,
>  };
>  
>  static void bdrv_nbd_init(void)
>