[V6,2/8] block: Allow the user to define "node-name" option both on command line and QMP.

From: Benoît Canet <benoit@irqsave.net>

Signed-off-by: Benoit Canet <benoit@irqsave.net>
---
 block.c          | 36 ++++++++++++++++++++++++++++++++++++
 qapi-schema.json |  2 ++
 2 files changed, 38 insertions(+)

Le Thursday 23 Jan 2014 à 21:31:33 (+0100), Benoît Canet a écrit :
> From: Benoît Canet <benoit@irqsave.net>
> 
> Signed-off-by: Benoit Canet <benoit@irqsave.net>
> ---
>  block.c          | 36 ++++++++++++++++++++++++++++++++++++
>  qapi-schema.json |  2 ++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/block.c b/block.c
> index 60b70bc..d9d02d2 100644
> --- a/block.c
> +++ b/block.c
> @@ -728,6 +728,33 @@ static int bdrv_open_flags(BlockDriverState *bs, int flags)
>      return open_flags;
>  }
>  
> +static int bdrv_assign_node_name(BlockDriverState *bs,
> +                                 const char *node_name,
> +                                 Error **errp)
> +{
> +    if (!node_name) {
> +        return 0;
> +    }
> +
> +    /* empty string node name is invalid */
> +    if (node_name[0] == '\0') {
> +        error_setg(errp, "Empty node name");
> +        return -EINVAL;
> +    }
> +
> +    /* takes care of avoiding duplicates node names */
> +    if (bdrv_find_node(node_name)) {
> +        error_setg(errp, "Duplicate node name");
> +        return -EINVAL;
> +    }
> +
> +    /* copy node name into the bs and insert it into the graph list */
> +    pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
> +    QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
> +
> +    return 0;
> +}
> +
>  /*
>   * Common part for opening disk images and files
>   *
> @@ -738,6 +765,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
>  {
>      int ret, open_flags;
>      const char *filename;
> +    const char *node_name = NULL;
>      Error *local_err = NULL;
>  
>      assert(drv != NULL);
> @@ -752,6 +780,14 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
>  
>      trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
>  
> +    node_name = qdict_get_try_str(options, "node-name");

> +    qdict_del(options, "node-name");

Kevin: I wonder if I delete the option too early hence zeroing node-name ? 

> +
> +    ret = bdrv_assign_node_name(bs, node_name, errp);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
>      /* bdrv_open() with directly using a protocol as drv. This layer is already
>       * opened, so assign it to bs (while file becomes a closed BlockDriverState)
>       * and return immediately. */
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 35f7b34..04167da 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -4090,6 +4090,7 @@
>  # @id:          #optional id by which the new block device can be referred to.
>  #               This is a required option on the top level of blockdev-add, and
>  #               currently not allowed on any other level.
> +# @node-name:   #optional the name of a block driver state node (Since 2.0)
>  # @discard:     #optional discard-related options (default: ignore)
>  # @cache:       #optional cache-related options
>  # @aio:         #optional AIO backend (default: threads)
> @@ -4105,6 +4106,7 @@
>  { 'type': 'BlockdevOptionsBase',
>    'data': { 'driver': 'str',
>              '*id': 'str',
> +            '*node-name': 'str',
>              '*discard': 'BlockdevDiscardOptions',
>              '*cache': 'BlockdevCacheOptions',
>              '*aio': 'BlockdevAioOptions',
> -- 
> 1.8.3.2
>