1debugfs: ex /a
2Level Entries       Logical      Physical Length Flags
3 0/ 1   1/  1     0 -     0     9              1
4 1/ 1   1/  1     0 -     0    10 -    10      1
5Pass 1: Checking inodes, blocks, and sizes
6Inode 12 extent tree (at level 1) could be shorter.  Fix? yes
7
8Pass 1E: Optimizing extent trees
9Pass 2: Checking directory structure
10Pass 3: Checking directory connectivity
11Pass 4: Checking reference counts
12Pass 5: Checking group summary information
13
14test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
15test_filesys: 12/128 files (0.0% non-contiguous), 19/512 blocks
16Exit status is 0
17