Index: libexec/rc/rc.d/root
===================================================================
--- libexec/rc/rc.d/root
+++ libexec/rc/rc.d/root
@@ -30,7 +30,9 @@
 		;;
 	esac
 
-	umount -a >/dev/null 2>&1
+	# Evey filesystem listed in fstab except root is umounted here so that
+	# subsequent mounting services could operate on a well-defined state.
+	umount -A
 
 	# If we booted a special kernel remove the record
 	# so we will boot the default kernel next time.