[RFC v1] nvme: add cse, ds, ms, nsze and nuse to sysfs

[Christoph Hellwig]

On Mon, Nov 27, 2023 at 09:30:14AM -0700, Keith Busch wrote:
> > > Should this even be an nvme specific attribute? I thought we should have
> > > blk-integrity.c report its 'tuple_size' attribute instead. That should
> > > work as long as we're not dealing with extended metadata at least, but
> > > that's kind of a special format that doesn't have block layer support.
> > 
> > Reporting the tuple size is a good idea.  But is that enough for
> > the existing nvme-cli use case?
> 
> nvme-cli currently queries with admin passthrough identify command, so
> adding a new attribute won't break that. I assume Daniel would have it
> fallback to that same command for backward compatibilty if a desired
> sysfs attribute doesn't exist.

Yes.  But does it care about the tuple size, or the actual size of the
metadata field even if is bigger than the PI tuple?