Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
test_filesys: 13/128 files (7.7% non-contiguous), 574/2048 blocks
Exit status is 0
debugfs: ex /a
Level Entries       Logical      Physical Length Flags
 0/ 0   1/  1     0 -   511  1025 -  1536    512 
debugfs: ex /zero
Level Entries       Logical      Physical Length Flags
 0/ 0   1/  4     0 -     0    27 -    27      1 
 0/ 0   2/  4     2 -     2    29 -    29      1 
 0/ 0   3/  4     4 -     4    31 -    31      1 
 0/ 0   4/  4     6 -     6    33 -    33      1