Anton Nefedov <anton.nefe...@virtuozzo.com> writes:
> On 13/12/2018 3:20 PM, Markus Armbruster wrote:
>> I'm reviewing just the QAPI schema today.
>>
>> Anton Nefedov <anton.nefe...@virtuozzo.com> writes:
>>
>>> A block driver can provide a callback to report driver-specific
>>> statistics.
>>>
>>> file-posix driver now reports discard statistics
>>>
>>> Signed-off-by: Anton Nefedov <anton.nefe...@virtuozzo.com>
[...]
>>> @@ -892,6 +927,8 @@
>>> #
>>> # @stats: A @BlockDeviceStats for the device.
>>> #
>>> +# @driver-specific: Optional driver-specific stats. (Since 4.0)
>>> +#
>>> # @parent: This describes the file block device if it has one.
>>> # Contains recursively the statistics of the underlying
>>> # protocol (e.g. the host file for a qcow2 image). If there is
>>> @@ -905,6 +942,7 @@
>>> { 'struct': 'BlockStats',
>>> 'data': {'*device': 'str', '*qdev': 'str', '*node-name': 'str',
>>> 'stats': 'BlockDeviceStats',
>>> + '*driver-specific': 'BlockStatsSpecific',
>>> '*parent': 'BlockStats',
>>> '*backing': 'BlockStats'} }
>>>
>>
>> Feels awkward.
>>
>> When is @driver-specific present? Exactly when the driver is 'file' or
>> 'host_device'? If that's correct, then turning BlockStats into a union
>> would be clearer and reduce parenthesises on the wire:
>>
>> { 'union': 'BlockStats',
>> 'base': {
>> 'driver': 'BlockdevDriver',
>> ... all the other existing members of BlockStats ... }
>> 'discriminator': 'driver',
>> 'data': {
>> 'file': 'BlockStatsSpecificFile',
>> 'host_device': 'BlockStatsSpecificFile' } }
>>
>> [...]
>>
>
> this series drags for quite a while - we already discussed this :)
> In short: Blockdev does not always have driver, so it's either this
> or adding weird BlockdevDriver values like "none".
>
> http://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg01845.html
You're right.
