Re: Can not use hmp block_resize command with -blockdev option

[zhao xiaojun]

Thanks you, that's really good idea. And I also have the following question:

There are some hmp and qmp commands in my scripts, they need the device as an argument. Recently. i used the -blockdev replace the -drive to specify the disk drive, then use  qmp's query_block to query the device,  but the device is NULL string. For the hmp's block_resize, I can use qmp's block_resize do. But the other commands(qpm's block-job-cancel etc.), they only support the device argument. So I can only continue to use -drive to specify disk drive.  

I was trying to see the source(qemu v5.1.0):

qmp_query_device()

  -> bdrv_query_info()

      info->device = g_strdup(blk_name(blk))

the device is set to blk_name(blk), and the blk->name is set in the monitor_add_blk()

the -blockdev:

qmp_blockdev_add()

   -> bds_tree_init()

     -> bdrv_open()

   ...

the qmp_blockdev_add() doesn't call the monitor_add_blk().

Questions:

Why can not qmp_blockdev_add() call the monitor_add_blk()? 

Will the hmp and qmp commands that only support device as an argument be compat with the -blockdev option? 

Kevin Wolf <kwolf@redhat.com> 于2021年3月18日周四 下午6:50写道：

Am 17.03.2021 um 23:49 hat John Snow geschrieben:
> On 3/16/21 11:43 PM, zhao xiaojun wrote:
> > Hi,
> > I use -blockdev option to specify a drive when qemu boot and i want to
> > resize it with hmp block_resize command. The hmp block_resize comand's
> > arguments: block_resize device new_size.
> > So I query the device by qmp query_block command, but the device filed
> > of the result output is NULL string.
> >
> > result output:
> > {
> >    "return": [
> >      {
> >        "io-status": "ok",
> >        "device": "",
> >          ...
> > }
> >
> > I noticed that the qmp block_resize command supports device or node-name
> > as argument.
> >
> > If i can continue use the the hmp block_resize command with the device
> > argument?
> >
> > Regards.
>
> I'm not sure what you're asking: hmp's block_resize doesn't accept node-name
> arguments as you've found. Are you not able to use QMP's block_resize?

We should probably fix HMP block_resize to accept node names.

Kevin