Invalid superblock and bad magic number prevent file system repair

[Daan]

After some other trouble (see my thread "Restore Debian Lenny after failed partion resize?"), file system checks on the Debian root partition during boot fail. I tried from a live CD too, but no avail. e2fsck says the superblock is invalid, and trying the superblock backups also seems to fail. It suggests using alternative superblocks. I've tried several locations but all failed. I'm not sure I got the locations right, because the method for determining where they are which I found on the web uses dumpe2fs which fails because of the bad superblock. The partition is ext3 and was created by the Debian Lenny installer.

root@PartedMagic:~# e2fsck /dev/sda5
e2fsck 1.41.3 (12-Oct-2008)
e2fsck: Superblock invalid, trying backup blocks...
e2fsck: Bad magic number in super-block while trying to open /dev/sda5

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>

root@PartedMagic:~# e2fsck -b 8193 /dev/sda5
e2fsck 1.41.3 (12-Oct-2008)
e2fsck: Bad magic number in super-block while trying to open /dev/sda5

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>

root@PartedMagic:~# dumpe2fs /dev/sda5
dumpe2fs 1.41.3 (12-Oct-2008)
dumpe2fs: Bad magic number in super-block while trying to open /dev/sda5
Couldn't find valid filesystem superblock.
root@PartedMagic:~# e2fsck -b 32768 /dev/sda5
e2fsck 1.41.3 (12-Oct-2008)
e2fsck: Bad magic number in super-block while trying to open /dev/sda5

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>

root@PartedMagic:~# e2fsck -b 98304 /dev/sda5
e2fsck 1.41.3 (12-Oct-2008)
e2fsck: Invalid argument while trying to open /dev/sda5

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>

root@PartedMagic:~# dmesg | tail
usb 4-1: Manufacturer: Logitech
hub 4-0:1.0: state 7 ports 2 chg 0000 evt 0002
hub 7-0:1.0: hub_suspend
usb usb7: bus auto-suspend
ehci_hcd 0000:00:1d.7: suspend root hub
ADDRCONF(NETDEV_UP): eth0: link is not ready
0000:00:19.0: eth0: Link is Up 100 Mbps Full Duplex, Flow Control: RX/TX
0000:00:19.0: eth0: 10/100 speed: disabling TSO
ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
eth0: no IPv6 routers present
root@PartedMagic:~# tune2fs -l /dev/sda5
tune2fs 1.41.3 (12-Oct-2008)
tune2fs: Bad magic number in super-block while trying to open /dev/sda5
Couldn't find valid filesystem superblock.

So, I have an invalid superblock and a bad magic number. I don't know what those are, but I want them fixed.

Any suggestions?

Thanks.

[Daan]

No errors during boot after I've updated my fstab. efsck thought my swap was my root partition...