1 e2fsck external journal
2 ../e2fsck/e2fsck: Filesystem has unsupported feature(s) while trying to open test.img
4 The superblock could not be read or does not describe a valid ext2/ext3/ext4
5 filesystem. If the device is valid and it really contains an ext2/ext3/ext4
6 filesystem (and not swap or ufs or something else), then the superblock
7 is corrupt, and you might try running e2fsck with an alternate superblock:
8 e2fsck -b 8193 <device>
10 e2fsck -b 32768 <device>
13 dumpe2fs external journal
14 Filesystem volume name: <none>
15 Last mounted on: <not available>
16 Filesystem magic number: 0xEF53
17 Filesystem revision #: 1 (dynamic)
18 Filesystem features: journal_dev metadata_csum
19 Default mount options: user_xattr acl block_validity
20 Filesystem state: clean
21 Errors behavior: Continue
22 Filesystem OS type: Linux
25 Reserved block count: 0
31 Blocks per group: 8192
32 Fragments per group: 8192
34 Inode blocks per group: 0
36 Check interval: 0 (<none>)
37 Reserved blocks uid: 0
38 Reserved blocks gid: 0
41 Required extra isize: 28
42 Desired extra isize: 28
43 Default directory hash: half_md4
45 Journal features: journal_64bit journal_checksum_v3
46 Total journal size: 2048k
47 Total journal blocks: 2048
48 Max transaction length: 2048
50 Journal first block: 3
51 Journal sequence: 0x00000003
53 Journal checksum type: crc32c
54 Journal checksum: 0x661e816f
55 Journal users: 117f752e-f27d-4f6f-a652-072586a29b82