[PATCH 2/2] nvme: re-read ANA log page after ns scan completes

[Hannes Reinecke]

On 4/3/25 17:37, Keith Busch wrote:
> On Thu, Apr 03, 2025 at 05:32:59PM +0200, Hannes Reinecke wrote:
>> On 4/3/25 16:55, Keith Busch wrote:
>>> On Thu, Apr 03, 2025 at 09:19:30AM +0200, Hannes Reinecke wrote:
>>>> When scanning for new namespaces we might have missed an ANA AEN,
>>>> so we should always re-read the ANA log page after scanning to ensure
>>>> we don't miss updates there.
>>>
>>> Worst case we might check a log page that hasn't changed. Rescans should
>>> be rare, so I guess it's fine. But I'm not sure why scanning might cause
>>> an ANA AEN to be missed. ?
>> Well, it's not that we're _missing_ AENs here.
>> As per quoted spec ANA change events are not sent if there had been
>> an event (on the controller) which would have caused both an ANA change
>> event and an NS changed AEN to be sent.
>>
>> So any NS changed event really needs to be treated as a combination of
>> NS changed _and_ ANA changed, and after each namespace rescan we need
>> to re-read the ANA log page.
> 
> Oh, good call. I forgot about that text.

NP. We all did :-)

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
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