Disk I/O errors while reading journal during boot
An io error during fsck / single user mode means inventory your backups, perform data recovery if needed, format and erase the drive. 

At that point, you will either have a stable volume to reinstall the OS or continuing hardware errors meaning a repair or drive swap. 

You could also buy time by installing the OS on to an external drive and postpone the data recovery / backup decision point. Often failing drives work well for read operations for far longer than any write operations.