ls -l /sys/fs/bcache/
total 0
drwxr-xr-x 7 root root    0 Aug 12 21:28 af7bbe93-7bb8-4789-b879-a033c1331223
--w------- 1 root root 4096 Aug 12 21:25 register
--w------- 1 root root 4096 Aug 12 21:25 register_quiet