If you are finding this in your /var/log/messages file, it most likely means your Harddrive is failing or going to fail very soon.
I tried fscking it
# fsck /dev/hda
However that returned:
Couldn’t find ext2 superblock, trying backup blocks…
fsck.ext2: Bad magic number in super-block while trying to open /dev/hda
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>
Which means it definitely is the harddrive failing. Time to replace it!