[CentOS] verify clean umount

This is on a C6 systems.

How can I verify that an ext4 data partition is being unmounted properly at (reboot/shutdown) on a sysV init system. I've looked at S01reboot and S01halt scripts in etc but what I'm concerned about is that I mounted my partition on a tmpfs dir mount point. So if those S01 scripts try to umount the tmpfs dir first they may get a "target busy" and then they will try a force umount. (I think that's not good)

Basically I'm trying to verify that the partition (on reboot/shutdown) is being unmounted before its tmpfs mount point. Is there an easy way to verify this?