+ext2fs_open2: The ext2 superblock is corrupt
../e2fsck/e2fsck: Superblock invalid, trying backup blocks...
-../e2fsck/e2fsck: The ext2 superblock is corrupt while trying to open ./test.img
+../e2fsck/e2fsck: The ext2 superblock is corrupt while trying to open test.img
-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
+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