Creating a simple directory structure leads to the following error:
$ btrfs check
Checking filesystem on test.img
UUID: 8f2292ad-c80e-4ab4-8a72-29aa3a83002c
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
[4/7] checking fs roots
unresolved ref dir 260 index 0 namelen 2 name .. filetype 0 errors 3, no dir item, no dir index
ERROR: errors found in fs roots
found 101085184 bytes used, error(s) found
total csum bytes: 98460
total tree bytes: 262144
total fs tree bytes: 49152
total extent tree bytes: 16384
btree space waste bytes: 151864
file data blocks allocated: 167931904
referenced 167931904
The self-reference should exist for the toplevel directory, where the
parent directory points to itself.
Issue: #453
Author: tyan0
Signed-off-by: David Sterba <dsterba@suse.com>