You might be able to repair it using fsck. Boot to runlevel 1 and type:
fsck -f -p
With this you will unmount the "root" filesystem, and unmount the "/boot" filesystem and then run the filesystem check program on files and automatically fix option. However if the filesystem is really borked, you might might have to run with just the fsck -p option and manually answer about fixing the inodes, etc.....