Do we need an opt-in for file systems use of hw atomic writes?

[Christoph Hellwig]

On Tue, Jul 15, 2025 at 06:53:29AM +1000, Dave Chinner wrote:
> This isn't a filesystem question - this is a question about what
> features the block device should expose by default to the
> user/filesystem by default.

It's both.  As I said before we've spent a lot of time making the file
systems less reliant on hardware getting everything right by adding
checksums (for metadata everywhere, and non-XFS file systems for data),
lsn verifications, etc.  And now we go all in to trust a new (in case
of nvme very much misdesigned) feature.

I'm perfectly fine offering that use, but I'm a lot less excited by
automatically using using it due to my deep mistrust of hardware.