Comment 6 for bug 1039887

So in 15.04 Vivid, systemd is used by default which has a remount service for all entries listed in /etc/fstab. It's a simple solution and works good enough.

A similar thing can be implemented in mountall as well. My previous attempt at intelligently parsing all the options to detect whether a remount is needed is complex, due to all the options that could be used (some negating others, or ignored by kernel).