e2fsck external journal ../e2fsck/e2fsck: Filesystem has unsupported feature(s) while trying to open test.img The superblock could not be read or does not describe a valid ext2/ext3/ext4 filesystem. If the device is valid and it really contains an ext2/ext3/ext4 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 8193 <device> or e2fsck -b 32768 <device> Exit status is 8 dumpe2fs external journal Filesystem volume name: <none> Last mounted on: <not available> Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: journal_dev metadata_csum Default mount options: user_xattr acl block_validity Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 0 Block count: 2048 Reserved block count: 0 Free blocks: 0 Free inodes: 0 First block: 1 Block size: 1024 Fragment size: 1024 Blocks per group: 8192 Fragments per group: 8192 Inodes per group: 0 Inode blocks per group: 0 Mount count: 0 Check interval: 0 (<none>) Reserved blocks uid: 0 Reserved blocks gid: 0 First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Default directory hash: half_md4 Checksum type: crc32c Journal checksum type: crc32c Journal checksum: 0x661e816f Journal features: journal_64bit journal_checksum_v3 Journal block size: 1024 Journal length: 2048 Journal first block: 3 Journal sequence: 0x00000003 Journal start: 0 Journal number of users: 1 Journal users: 117f752e-f27d-4f6f-a652-072586a29b82