[root@sysrescue /mnt]# sudo mount /dev/sdf1 x
mount: /mnt/x: wrong fs type, bad option, bad superblock on /dev/sdf1, missing codepage or helper program, or other error.

[root@sysrescue /mnt]# btrfsck /dev/sdf1
Opening filesystem to check...
Checking filesystem on /dev/sdf1
UUID: 314a88f5-d210-4c03-b79b-8c284e9de0ca
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
block group 1347576397824 has wrong amount of free space, free space cache has 32768 block group has 21757952
failed to load free space cache for block group 1347576397824
there is no free space entry for 3122471567360-3122471583744
there is no free space entry for 3122471567360-3122471632896
cache appears valid but isn't 3121397891072
block group 5073460527104 has wrong amount of free space, free space cache has 622592 block group has 93597130752
failed to load free space cache for block group 5073460527104
block group 5796088774656 has wrong amount of free space, free space cache has 4096 block group has 528384
failed to load free space cache for block group 5796088774656
block group 5907757924352 has wrong amount of free space, free space cache has 4096 block group has 266240
failed to load free space cache for block group 5907757924352
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
found 5988193943552 bytes used, error(s) found
total csum bytes: 5835425576
total tree bytes: 10667114496
total fs tree bytes: 4041867264
total extent tree bytes: 429441024
btree space waste bytes: 996912757
file data blocks allocated: 6038381948928
 referenced 6257201074176