VFS: Can't find ext3 filesystem on dev hdc1.
mount: wrong fs type, bad option, bad superblock on /dev/hdc1,
       missing codepage or other error
              In some cases useful info is found in syslog - try
	             dmesg | tail  or so

militux:~# fsck.ext3 /dev/hdc1
e2fsck 1.39 (29-May-2006)
Couldn't find ext2 superblock, trying backup blocks...
fsck.ext3: Bad magic number in super-block while trying to open /dev/hdc1

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 8193 <device>


Hi,

A filesystem can be corrupted so it can't be mounted, the result of damage to 
the filesystem's superblock. Any attempt to mount it will fail.
The filesystem keeps backups of the superblock. 
THere are backup copies of the superblock at block offsets 8193, 16385 (8192 x 
2 + 1), 24577 (8192 x 3 +1)

you can check for the size of superblocks with dumpe2fs <device> | more
if the size is different use that in the formula above. 
mine is Blocks per group: 32768

you can run e2fsck using a copy of the superblock

Example: mount -o sb=n /dev/hda1 /usr

e2fsck -f -b <offset> <device>

eg. e2fsck -f -b 16385 /dev/hda1

(taken from 'running linux' by Matt Welsh and Lar Kaufmann)

fsck.ext3 -S pra refazer super-blocks

debugfs -s <superbock> <device>

these are common # for backup superblocks in case u have not noted them
down:

32768, 655539, 98304, 131072, 163840, 229376, 294912, 819200

The location of the backup superblock is dependent on the filesystem’s blocksize.
For filesystems with 1k blocksizes, a backup superblock can be found at block 8193;
for filesystems with 2k blocksizes, at block 16384; and for 4k blocksizes, at block 32768