I was reading the
rmlint manual, and one of the duplicate handlers are clone and reflink:
· clone: btrfs only. Try to clone both files with the BTRFS_IOC_FILE_EXTENT_SAME ioctl(3p). This will physically delete duplicate extents. Needs at least kernel 4.2.
· reflink: Try to reflink the duplicate file to the original. See also --reflink in man 1 cp. Fails if the filesystem does not support it.
What exactly does this clone do, and how is it different from a reflink? What does the BTRFS_IOC_FILE_EXTENT_SAME ioctl do?