This article is mainly for my internal documentation (In case it ever happens again 🙂 ) I had some file system issues with my PFSense SG-8860 (which is a very cool firewall).
After a power outage it went in a reboot loop. I had to connect with the USB console cable and then I fixed it with the following commands:

/sbin/fsck -y /

Run it repeatedly until it no longer reports any errors, at least 3 times. Then reboot with:

/sbin/reboot