Re: What should we do about the nvme atomics mess?

[Christoph Hellwig <hch@lst.de>]

On Mon, Jul 07, 2025 at 09:56:53AM -0600, Keith Busch wrote:
> I think the NVMe TWG might want to consider an ECN to deprecate or at
> least recommend against AUWPF, too.

Yeah.  A wording that every controller SHOULD implement NAWUPF if it
implements AWUPF might be good, eventually upgraded to a SHALL.

> Just to throw AWUPF a lifeline for legecy devices, we could potentially
> make sense of the value if Identify Controller says:
> 
>   1. CMIC == 0; and
>   2. OACS.NMS == 0; and

What is NMS meant to say?  namespace management support?

>   3.
>     a. FNA.FNS == 1; or
>     b. NN == 1
> 
> And if those conditions are true, then the controller and namespace
> scopes resolve to a single namespace format, so the values should be one
> in the same. The only way it could change, then, is a format command,
> which means there couldn't be an in-use filesystem depending on it not
> changing.

We could.  But are there many controllers where that would be the
case and where people want to use atomics?