A VM’s filesystem (which was using LVM) was corrupt and it couldn’t boot.

All I did was force boot from systemrescuecd and ran the following command:

fsck.ext4 /dev/vgname/lvname

Note: Switch ext4 to any other type of filesystem you have, e.g. ext3

Source: https://forums.fedoraforum.org/archive/index.php/t-139776.html