System went read-only suddenly

Your root file system is mounted read-only. This likely happened on a reboot. There are a few options:

• Configure the system to fix errors during reboot. On Ubuntu this is controlled by the FSCKFIX option in the file /etc/default/rcS.
• Reboot in recovery mode and run fsck -f /dev/disk/by-uuid/e45e30eb-efa4-4cd9-aaf9-c6cbe46aa41c and reboot again.
• Boot from a recovery disk and run fsck as shown above.

All options will require your system to be down for a bit. However, it appears it is effectively down now.

It may be possible to run fsck without rebooting and remount the system rw. I would run a test fsck without enabling fixing problems to see how broken the file system