mke2fs -F -O resize_inode -o Linux -b 1024 -g 1024 test.img 16384
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
4096 inodes, 16384 blocks
819 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=8421376
16 block groups
1024 blocks per group, 1024 fragments per group
256 inodes per group
Superblock backups stored on blocks: 
	1025, 3073, 5121, 7169, 9217

Writing inode tables:  0/16 1/16 2/16 3/16 4/16 5/16 6/16 7/16 8/16 9/1610/1611/1612/1613/1614/1615/16done                            
Writing superblocks and filesystem accounting information: done

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: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 0
-----------------------------------------------
 
debugfs -R ''set_inode_field <7> block[2] 42'' -w ./test.img
Exit status is 0
Resize inode not valid.  Recreate? yes

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
Free blocks count wrong for group #0 (717, counted=718).
Fix? yes

Free blocks count wrong (14276, counted=14277).
Fix? yes


test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
test_filesys: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 1
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: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 0
-----------------------------------------------
 
debugfs -R ''clri <7>'' -w ./test.img
Exit status is 0
Resize inode not valid.  Recreate? yes

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
Free blocks count wrong for group #0 (717, counted=718).
Fix? yes

Free blocks count wrong (14276, counted=14277).
Fix? yes


test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
test_filesys: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 1
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: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 0
-----------------------------------------------
 
debugfs -R ''set_inode_field <7> bmap[524] 57'' -w ./test.img
Exit status is 0
Resize inode not valid.  Recreate? yes

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
Free blocks count wrong for group #0 (717, counted=718).
Fix? yes

Free blocks count wrong (14276, counted=14277).
Fix? yes


test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
test_filesys: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 1
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: 11/4096 files (0.0% non-contiguous), 2107/16384 blocks
Exit status is 0
-----------------------------------------------
 
debugfs -R ''set_super_value reserved_gdt_blocks 15679'' -w ./test.img
Exit status is 0
Corruption found in superblock.  (reserved_gdt_blocks = 15679).

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 1025 <device>

Exit status is 8
-----------------------------------------------
 
debugfs -R ''set_super_value reserved_gdt_blocks 32'' -w ./test.img
Exit status is 0
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
Block bitmap differences:  -(35--258) -(1059--1282) -(3107--3330) -(5155--5378) -(7203--7426) -(9251--9474)
Fix? yes

Free blocks count wrong for group #0 (718, counted=942).
Fix? yes

Free blocks count wrong for group #1 (732, counted=956).
Fix? yes

Free blocks count wrong for group #3 (732, counted=956).
Fix? yes

Free blocks count wrong for group #5 (732, counted=956).
Fix? yes

Free blocks count wrong for group #7 (732, counted=956).
Fix? yes

Free blocks count wrong for group #9 (732, counted=956).
Fix? yes

Free blocks count wrong (14277, counted=15621).
Fix? yes


test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
test_filesys: 11/4096 files (0.0% non-contiguous), 763/16384 blocks
Exit status is 1
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: 11/4096 files (0.0% non-contiguous), 763/16384 blocks
Exit status is 0
