Re: [Qemu-devel] [PATCH 2/4] block: use Error mechanism instead of -errno for block_job_set_speed()

[Eric Blake]

On 04/24/2012 03:01 AM, Paolo Bonzini wrote:
> Il 24/04/2012 10:49, Stefan Hajnoczi ha scritto:
>> "The error is specific to
>> block job speeds so we can add a speed argument to block-stream in the
>> future and clearly identify the invalid parameter."
>>
>> I added the new error to avoid having to change the InvalidParameter
>> 'name' field.  It becomes ugly because we have:
>> block-job-set-speed <device> <value>
>> block-stream <device> [<speed>] [<base>]
>>
>> Notice that the parameter is called 'value' in block-job-set-speed and
>> 'speed' in block-stream.  Therefore we can't just propagate a single
>> InvalidParameter name='value' error up from block-stream.
>>
>> This means that QMP commands will need to change the error to use the
>> correct name :(.  It's doable, but ugly and a bit more complex.
> 
> Well, we still have time to change block-job-set-speed.  Ugly, but doable.

block-job-set-speed <device> <speed>

would indeed let you use 'speed' as the parameter name in both calls,
and I can just as easily make libvirt target the name 'value' for
block_job_set_speed and 'speed' for block-job-set-speed.  I'm okay with
that idea, if it makes the rest of your patch easier.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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