Re: [Qemu-devel] QMP: RFC: I/O error info & query-stop-reason

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/07/2011 10:41 AM, Markus Armbruster wrote:
> Luiz Capitulino<lcapitulino@redhat.com>  writes:
>
>> On Mon, 06 Jun 2011 08:08:51 -0500
>> Anthony Liguori<anthony@codemonkey.ws>  wrote:
>>
>>> On 06/06/2011 04:25 AM, Kevin Wolf wrote:
>>>> Am 02.06.2011 20:09, schrieb Luiz Capitulino:
>>>>>>> I'm ok with either way. But in case you meant the second one, I guess
>>>>>>> we should make "reason" a dictionary so that we can group related
>>>>>>> information when we extend the field, for example:
>>>>>>>
>>>>>>>     "reason": { "no space": false, "no permission": true }
>>>>
>>>> Splitting up enums into a number of booleans looks like a bad idea to
>>>> me. It makes things more verbose than they should be, and even worse, it
>>>> implies that more than one field could be true.
>>>
>>> I agree.  What I had suggested was to not have a reason at all.
>>
>> Is it better if we add a new enum to query-block? Like the "io-error" key we
>> have talked about earlier? Like:
>>
>>   "io-error": "no space"
>>
>> We could have "no space", "low level" (that's how the man page defines EIO) and
>> "unknown".
>
> As mentioned before, I prefer my errnos straight, not wrapped in a pile
> of pseudo-abstractions that make me go to the source code to figure out
> how to unwrap them :)

You want a log file.  You want to spit out open strings that contain 
actual errno numbers.

I'm 100% supportive of that.

But QMP is an interface that we have to maintain forever and passing a 
valid that can be different on different platforms, that depends on the 
semantics of whatever function calls happen to currently be in the path, 
is not a good long term interface.

We need to separate what we want to have as developers trying to debug 
and what we need to provide as a long term supported management interface.

If we separately the two, we'll be much happier in both places.

Regards,

Anthony Liguori

>