Note - anyone bored enough could already make any of these tools work by using FICLONERANGE (which ZFS already supports), but you'd have to do locking - lock, c

Note - anyone bored enough could already make any of these tools work by using FICLONERANGE (which ZFS already supports), but you'd have to do locking - lock, compare file ranges, clone, unlock. Because FIDEDUPRANGE has the compare as part of the atomic guarantee, you don't need to lock in userspace around using it, and so no dedup utility bothers to do FICLONERANGE + locking. Also, ZFS is the only FS that implements FICLONERANGE but not FIDEDUPRANGE :)