This functions will:
- umount all mount points that aren't API
- remount read-only all mount points that can't be umounted
- umount all swap devices.
- detach all loopback devices
TODO:
- umount dms
Mountpoints are being read from /proc/self/mountinfo.
Swaps are being read from /proc/swaps.
Loop devices from /sys/class/block/loop*.