block_set_io_throttle complaints Need exactly one of 'device' and 'id'

All of sudden, after a qemu update, block_set_io_throttle does not work anymore.

Full command to QEMU monitor -- 

(qemu) block_set_io_throttle db 0 0 0 0 0 0
Need exactly one of 'device' and 'id'

The help text still point to the same old syntax, which no longer works.

On 03/30/2017 02:14 AM, dE wrote:
> Public bug reported:
> 
> All of sudden, after a qemu update, block_set_io_throttle does not work
> anymore.
> 
> Full command to QEMU monitor --
> 
> (qemu) block_set_io_throttle db 0 0 0 0 0 0
> Need exactly one of 'device' and 'id'
> 
> The help text still point to the same old syntax, which no longer works.

Broken in 2.8, fixed here (will be in 2.9):

commit 3f35c3b166c18043596768448e5d91b5d52f8353
Author: Eric Blake <email address hidden>
Date:   Fri Jan 20 17:03:59 2017 -0600

    hmp: fix block_set_io_throttle

    Commit 7a9877a made the 'device' parameter to BlockIOThrottle
    optional, favoring 'id' instead.  But it forgot to update the
    HMP usage to set has_device, which makes all attempts to change
    throttling via HMP fail with "Need exactly one of 'device' and 'id'"

    CC: <email address hidden>
    Signed-off-by: Eric Blake <email address hidden>
    Message-Id: <email address hidden>
    Reviewed-by: Stefan Hajnoczi <email address hidden>
    Signed-off-by: Dr. David Alan Gilbert <email address hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org