Re: [PATCH 2/2] nvme: fix unmatched id's under delayed path deletion

[Nilay Shroff <nilay@linux.ibm.com>]

On 2/26/26 10:21 PM, Keith Busch wrote:
> On Thu, Feb 26, 2026 at 04:37:40PM +0100, Christoph Hellwig wrote:
>> I find the retry logic a bit odd and different from other places
>> do in similar areas.  What I'd expected is either a "nr_retries" or
>> "did_retry" variable initialized to 0/false, then checked here to
>> be not set (plus the IS_ENABLED() for multipath) and incremented/set
>> below.
>>
>> But independent of that, the actual logic looks fine.
> 
> I was able to test this, and it does work when we're specifically
> blocking on the delayed removal. But there's a different race this
> doesn't handle: controller A's scan_work may depend on controller B's
> scan_work to finish first to remove a final reference on the deleted
> namespace when A is trying to add a newly created namespace that
> recycled the NSID.
> 
> This is looking pretty tricky to resolve. The best solution I'm coming
> up with so far is to have the scan_work synthesize a
> NVME_AER_NOTICE_NS_CHANGED event for every controller in the subsystem,
> then re-kick their scan work if the scan_work removed anything.

So does your disk when reuse NSID, changes ns ids such as NGUID/UUID/EUI64?

Thanks,
--Nilay