[PATCH 5/8] nvme: sync the namespace scanning during ctrl start

[Sagi Grimberg]

>>> Even in this case of re-creation we must sync the namespace 
>>> identification.
>>
>> But a format is not a re-creation.
>>
> 
> we currently don't support format in fabrics so maybe I didn't use the 
> correct word during my answer.
> 
> because of the dynamic nature of controllers and namespaces we have the 
> identify ctrl/ns commands in the specification and we need to use them.

ns scanning has been notorious to cause issues when executing with
controller resets. So I don't think it is a good idea to make ctrl start
block until it completes, especially not for an esoteric case that
a ns that suddenly was reformatted between reconnects.

> Re-queue requests to a non identified namespace is bad behavior. It 
> might be even a spec violation (I need to dig into the spec for it 
> probably and try to find some description on that scenario).

It can't be a spec violation, the host cannot know if there is any
aen pending (for example NS_CHANGE) when sending *ANY* command to the
controller.