Ok, este é provavelmente o melhor até agora: link , por @pwaller
Further to my previous answer, I have just released
fienode
which computes a SHA1 hash of the physical extents of the file and can be used to find some (identical) reflink copies. Beware though, there are caveats (see the documentation). BTRFS decided to change some, but not all, of the physical extents of a refink copy I made without provocation or warning, causing the value to change.