How to defragment compressed btrfs files?

If I defragment files on btrfs with the command btrfs filesystem defrag --step 1G file Everything is fine. A filefrag -v file clearly show, the extent count significantly decreased. Things are very different if I deal with compressed files. First, filefrag gives a huge amount of extents: Filesystem type is: 9123683e File size of file is 85942272 (20982 blocks of 4096 bytes) ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 31: 607198.. 607229: 32: encoded 1: 32.. 63: 609302.. 609333: 32: 607230: encoded 2: 64.. 95: 609314.. 609345: 32: 609334: encoded 3: 96.. 127: 609326.. 609357: 32: 609346: encoded ... 648: 20928.. 20959: 704298.. 704329: 32: 704299: encoded 649: 20960.. 20981: 691987.. 692008: 22: 704330: last,encoded,eof file: 650 extents found Second, if btrfs filesystem defragment commands return on the spot, without error report - and with an unchanged filefrag output. My impression is that fragmentation of compressed files is not an issue on btrfs filesystems et all. However, my ears clearly show: yes it is an issue for me. So, how to defragment on btrfs compressed file? How could I even see, are they even continuous, but not their encoded ( == compressed ) extents, instead their compressed blocks on the hdd?