Re: [Qemu-devel] [PATCH v2 2/6] qapi: add name parameter to nbd-server-add

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Vladimir Sementsov-Ogievskiy (vsementsov@virtuozzo.com) wrote:
> Allow user to specify name for new export, to not reuse internal
> node name and to not show it to clients.
> 
> This also allows creating several exports per device.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  qapi/block.json |  9 +++++++--
>  blockdev-nbd.c  | 14 +++++++++-----
>  hmp.c           |  5 +++--
>  3 files changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/qapi/block.json b/qapi/block.json
> index f093fa3f27..503d4b287b 100644
> --- a/qapi/block.json
> +++ b/qapi/block.json
> @@ -213,14 +213,19 @@
>  #
>  # @device: The device name or node name of the node to be exported
>  #
> +# @name: Export name. If unspecified @device parameter used as export name.
> +#        (Since 2.12)
> +#
>  # @writable: Whether clients should be able to write to the device via the
>  #     NBD connection (default false).
>  #
> -# Returns: error if the device is already marked for export.
> +# Returns: error if the server is not running, or export with the same name
> +#          already exists.
>  #
>  # Since: 1.3.0
>  ##
> -{ 'command': 'nbd-server-add', 'data': {'device': 'str', '*writable': 'bool'} }
> +{ 'command': 'nbd-server-add',
> +  'data': {'device': 'str', '*name': 'str', '*writable': 'bool'} }
>  
>  ##
>  # @nbd-server-stop:
> diff --git a/blockdev-nbd.c b/blockdev-nbd.c
> index 28f551a7b0..46c885aa35 100644
> --- a/blockdev-nbd.c
> +++ b/blockdev-nbd.c
> @@ -158,8 +158,8 @@ void qmp_nbd_server_start(SocketAddressLegacy *addr,
>      qapi_free_SocketAddress(addr_flat);
>  }
>  
> -void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
> -                        Error **errp)
> +void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
> +                        bool has_writable, bool writable, Error **errp)
>  {
>      BlockDriverState *bs = NULL;
>      BlockBackend *on_eject_blk;
> @@ -170,8 +170,12 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
>          return;
>      }
>  
> -    if (nbd_export_find(device)) {
> -        error_setg(errp, "NBD server already exporting device '%s'", device);
> +    if (!has_name) {
> +        name = device;
> +    }
> +
> +    if (nbd_export_find(name)) {
> +        error_setg(errp, "NBD server already has export named '%s'", name);
>          return;
>      }
>  
> @@ -195,7 +199,7 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
>          return;
>      }
>  
> -    nbd_export_set_name(exp, device);
> +    nbd_export_set_name(exp, name);
>  
>      /* The list of named exports has a strong reference to this export now and
>       * our only way of accessing it is through nbd_export_find(), so we can drop
> diff --git a/hmp.c b/hmp.c
> index 35a7041824..0ea9c09b58 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -2203,7 +2203,8 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
>              continue;
>          }
>  
> -        qmp_nbd_server_add(info->value->device, true, writable, &local_err);
> +        qmp_nbd_server_add(info->value->device, false, NULL,
> +                           true, writable, &local_err);
>  
>          if (local_err != NULL) {
>              qmp_nbd_server_stop(NULL);
> @@ -2223,7 +2224,7 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
>      bool writable = qdict_get_try_bool(qdict, "writable", false);
>      Error *local_err = NULL;
>  
> -    qmp_nbd_server_add(device, true, writable, &local_err);
> +    qmp_nbd_server_add(device, false, NULL, true, writable, &local_err);

I wont insist, but it would be nice if you wired up an optional
parameter on HMP as well.

Dave

>      if (local_err != NULL) {
>          hmp_handle_error(mon, &local_err);
> -- 
> 2.11.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK