[PATCH V3 0/3] Ensure ordered namespace registration during async scan

[Hannes Reinecke]

On 6/18/26 23:55, Keith Busch wrote:
> On Wed, Jun 17, 2026 at 07:41:58PM +0200, Maurizio Lombardi wrote:
>> Did you manage to find a solution for this race?
>> I just wanted to check whether you had any patches ready for testing since
>> this discussion.
> 
> At last month's LSFMM, I heard concerns that this would break something.
> I don't remember the specifics as I wasn't trying to push the issue. I
> think this feedback was from the more fabrics focused folks, maybe Randy
> Jennings, Nilay Shroff or John Meneghini remembers?

The problem here is namespace lifetime. The ns_ida is only ever released
at the very last step, so the 'number' of the namespace will only be 
freed once all references to the namespace are dropped.
So if you were trying to keep the namespace number ordered you would
have to delay the creation of the namespace until that point, and you
would induce a serialization between deletion and creation.
Which will drastically prolong the rescan process.
And of course you need to hope that no-one triggers another rescan
process while the old one isn't finished, as that would need to wait
for the previous one to finish, too.
Or you need to introduce a mechanism to terminate an already running
rescan process.
So really, not a good idea.

I fail to see why one cannot use persistent names here.

Cheers,

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