On Wed, Jan 10, 2024 at 10:04:00AM +1100, Dave Chinner wrote: > Hence history teaches us that we should be designing the API around > the generic filesystem function required (hard alignment of physical > extent allocation), not the specific use case that requires that > functionality. I disagree. The alignment requirement is an artefact of how you implement atomic writes. As the fs user I care that I can do atomic writes on a file and need to query how big the writes can be and what alignment is required. The forcealign feature is a sensible fs side implementation of that if using hardware based atomic writes with alignment requirements, but it is a really lousy userspace API. So with John's API proposal for XFS with hardware alignment based atomic writes we could still use force align. Requesting atomic writes for an inode will set the forcealign flag and the extent size hint, and after that it'll report atomic write capabilities. Roughly the same implementation, but not an API tied to an implementation detail.
