Re: [Qemu-devel] [PATCH v4 29/38] blockdev: Add blockdev-insert-medium

[Wen Congyang <wency@cn.fujitsu.com>]

On 07/21/2015 01:45 AM, Max Reitz wrote:
> And a helper function for that, which directly takes a pointer to the
> BDS to be inserted instead of its node-name (which will be used for
> implementing 'change' using blockdev-insert-medium).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  blockdev.c           | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  qapi/block-core.json | 17 +++++++++++++++++
>  qmp-commands.hx      | 37 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 102 insertions(+)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 481760a..a80d0e2 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2164,6 +2164,54 @@ void qmp_blockdev_remove_medium(const char *device, Error **errp)
>      }
>  }
>  
> +static void qmp_blockdev_insert_anon_medium(const char *device,
> +                                            BlockDriverState *bs, Error **errp)
> +{
> +    BlockBackend *blk;
> +    bool has_device;
> +
> +    blk = blk_by_name(device);
> +    if (!blk) {
> +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> +                  "Device '%s' not found", device);
> +        return;
> +    }
> +
> +    /* For BBs without a device, we can exchange the BDS tree at will */
> +    has_device = blk_get_attached_dev(blk);
> +
> +    if (has_device && !blk_dev_has_removable_media(blk)) {
> +        error_setg(errp, "Device '%s' is not removable", device);
> +        return;
> +    }
> +
> +    if (has_device && !blk_dev_is_tray_open(blk)) {
> +        error_setg(errp, "Tray of device '%s' is not open", device);
> +        return;
> +    }
> +
> +    if (blk_bs(blk)) {
> +        error_setg(errp, "There already is a medium in device '%s'", device);
> +        return;
> +    }
> +
> +    blk_insert_bs(blk, bs);
> +}
> +
> +void qmp_blockdev_insert_medium(const char *device, const char *node_name,
> +                                Error **errp)
> +{
> +    BlockDriverState *bs;
> +
> +    bs = bdrv_find_node(node_name);
> +    if (!bs) {
> +        error_setg(errp, "Node '%s' not found", node_name);
> +        return;
> +    }

Hmm, it is OK if the bs is not top BDS?

Thanks
Wen Congyang

> +
> +    qmp_blockdev_insert_anon_medium(device, bs, errp);
> +}
> +
>  /* throttling disk I/O limits */
>  void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
>                                 int64_t bps_wr,
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 63a83e4..84c9b23 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1925,6 +1925,23 @@
>  { 'command': 'blockdev-remove-medium',
>    'data': { 'device': 'str' } }
>  
> +##
> +# @blockdev-insert-medium:
> +#
> +# Inserts a medium (a block driver state tree) into a block device. That block
> +# device's tray must currently be open and there must be no medium inserted
> +# already.
> +#
> +# @device:    block device name
> +#
> +# @node-name: name of a node in the block driver state graph
> +#
> +# Since: 2.5
> +##
> +{ 'command': 'blockdev-insert-medium',
> +  'data': { 'device': 'str',
> +            'node-name': 'str'} }
> +
>  
>  ##
>  # @BlockErrorAction
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index ff6c572..b4c34fe 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -3991,6 +3991,43 @@ Example:
>  EQMP
>  
>      {
> +        .name       = "blockdev-insert-medium",
> +        .args_type  = "device:s,node-name:s",
> +        .mhandler.cmd_new = qmp_marshal_input_blockdev_insert_medium,
> +    },
> +
> +SQMP
> +blockdev-insert-medium
> +----------------------
> +
> +Inserts a medium (a block driver state tree) into a block device. That block
> +device's tray must currently be open and there must be no medium inserted
> +already.
> +
> +Arguments:
> +
> +- "device": block device name (json-string)
> +- "node-name": root node of the BDS tree to insert into the block device
> +
> +Example:
> +
> +-> { "execute": "blockdev-add",
> +     "arguments": { "options": { "node-name": "node0",
> +                                 "driver": "raw",
> +                                 "file": { "driver": "file",
> +                                           "filename": "fedora.iso" } } } }
> +
> +<- { "return": {} }
> +
> +-> { "execute": "blockdev-insert-medium",
> +     "arguments": { "device": "ide1-cd0",
> +                    "node-name": "node0" } }
> +
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "query-named-block-nodes",
>          .args_type  = "",
>          .mhandler.cmd_new = qmp_marshal_input_query_named_block_nodes,
>