On 6/14/19 11:12 AM, Max Reitz wrote:
> On 14.06.19 17:29, Vladimir Sementsov-Ogievskiy wrote:
>> 13.06.2019 1:09, Max Reitz wrote:
>>> When looking for a blkdebug node (which implements debug breakpoints),
>>> use bdrv_primary_bs() to iterate through the graph, because that is
>>> where a blkdebug node would be.
>>>
>>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>>
>> Honestly, don't know why blkdebug is always searched in ->file sequence,
> 
> Usually, blkdebug is just above the protocol node.  So
> 
> $format --file--> $protocol
> 
> becomes
> 
> $format --file--> blkdebug --file--> $protocol
> 
> This is why the existing code generally looks for blkdebug under the
> ->file link.

blkdebug is an interesting beast; there are use cases for both:

blkdebug -> qcow2 -> file

for debugging only guest-visible actions, and

qcow2 -> blkdebug -> file

for debugging specific qcow2 metadata actions.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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