On Tue, May 19, 2026 at 01:51:53PM -0700, Andy Lutomirski wrote:

quoted

Also note that FIEMAP still doesn't report devices, so you're still
playing with fire on multi-device reflink-aware filesystems like XFS.

A hash would be fine for me.

But really a nicer interface would translate logical ranges in a file
to some range identifier, where:

All this sounds really complicated and probably not doable.  But you
haven't answered the basic question, which is if your use cases already
has candidates and you just want to confirm them, or if you are
iterating all file logical to physical mappings in the file systems?

Can you explain your highlevel use case a bit?