Upgrade from netbsd-9 to netbsd-10 potentially breaks ZFS mounts

[David Brownlee <abs%absd.org@localhost>]

It looks like that between netbsd-9 and netbsd-10 the order of ZFS
mounts vs fstab has changed.

I've just upgraded a system which had ffs filesystems for / & /home,
and a zfs pool on /home/files

Before the upgrade the mount order was

/ (ffs)
/home (ffs)
/home/files (zfs)

after upgrade the exact same configuration gives:

/ (ffs)
/home/files (zfs)
/home (ffs)

resulting in /home/files being inaccessible. I'm not saying the new
order is wrong, it's just likely to break any existing configuration
which has a zfs mount on top of a non root filesystem in ffs...

Does anyone have any thoughts on the best approach? - a note in
NetBSD-10 release notes and fstab/zfs manpage?

David