Re: [Qemu-devel] [PATCH v5 05/11] iotests: allow resume_drive by node name

[Max Reitz]

On 23.01.19 14:31, Vladimir Sementsov-Ogievskiy wrote:
> 23.01.2019 16:22, Vladimir Sementsov-Ogievskiy wrote:
>> 16.01.2019 16:11, Max Reitz wrote:
>>> On 14.01.19 17:06, Vladimir Sementsov-Ogievskiy wrote:
>>>> 14.01.2019 17:46, Max Reitz wrote:
>>>>> On 29.12.18 13:20, Vladimir Sementsov-Ogievskiy wrote:
>>>>>> After node graph changes, we may not be able to resume_drive by device
>>>>>> name (backing files are not recursively searched). So, lets allow to
>>>>>> resume by node-name. Set constant name for breakpoints, to avoid
>>>>>> introducing extra parameters.
>>>>>
>>>>> Hm, I don't quite understand this reason.  Is this so you can create
>>>>> breakpoints on one node (which falls through to the first blkdebug node)
>>>>> and then remove them from another (falling through to the same blkdebug
>>>>> node)?
>>>>
>>>> add/remove breakpoint goes through ->file children, but my filter links
>>>> active disk as ->backing. So, before block-job start we can insert 
>>>> breakpoint
>>>> by device name. But then, when filter inserted, we can't remove breakpoint,
>>>> because my filter hides blkdebug with active disk under ->backing link.
>>>>
>>>> Maybe, right solution would be support backing links in 
>>>> bdrv_debug_breakpoint()
>>>> and bdrv_debug_remove_breakpoint() for the case when there is no file 
>>>> child.
>>>>
>>>> But being unsure about right behavior, I've decided to adjust the test.
>>>>
>>>> What about just do both  add/remove breakpoint through blkdebug node-name, 
>>>> to
>>>> make it less weird?
>>>
>>> Yes, I was mostly wondering about the "set constant name for
>>> breakpoints".  It doesn't seem necessary to me;
>>
>> It's just to not create extra parameters or something. Current code don't 
>> allow
>> to create several breakpoints in one blkdebug anyway (as @drive is used as
>> breakpoint name), so there is no reason for different names at all.
>>
>> I'll improve commit message to make it clean.
>>
> 
> Hmmm.
> 
> Or, finally, may be better to teach bdrv_debug_breakpoint() and
> bdrv_debug_remove_breakpoint() to skip filters with backing child?

I suppose that would be a question for my "Deal with filters" series.
It does make sense to me, though.

Max

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