My comp froze so i held the powerbutton for 5 seconds to force shutdown. I rebooted and then at the boot screen it just kept on spinning and spinning finally restart. I used the boot parameter -v it had a kernel panic, it said could not read 512 bytes for the journal header. I booted my install disk, went to disk utility then tried to repair it then it failed and said invaled content in journal.

Also, can't event boot into safe mode/ single user mode.

I tried to use the install disk went into the terminal i did:
diskutil disableJournal disk0s2
to disable journal because the problem has something to do with journaling
but it says An error occured journaling th filesystem: Could not mount disk (-9954)

I then tried diskutil force disable journal disk0s2
worked, then i reinabled it.
Rebooted and then it booted back up like nothing happened at all!

Any luck with this? I'm having the same issue with an external firewire drive. Shows up in /dev , but refuses to mount.