How to separate mount rights in nfsv4

Hello,
it's not clear to me how I can allow different access to different machines in NFSv4.
Because nfsv4 needs a root export with fsid=0, and all other mounts should be below that.

However, if the line with fsid=0 is not mountable to all nodes, also the mounts below it will fail.
And if the line with fsid=0 is mountable to all nodes, all further lines can provide no additional security!

Example; this is my current export:

/virtual_machines/kvm/export 10.48.0.0/24(rw,no_root_squash,async,subtree_check,fsid=0) /virtual_machines/kvm/export/hwnode1 10.48.0.10(rw,no_root_squash,async,subtree_check) /virtual_machines/kvm/export/hwnode2 10.48.0.11(rw,no_root_squash,async,subtree_check)

I have two hardware nodes for virtual machines. Ideally each one of them should be able to mount only its subdirectory, but the export shown above is the only working one I could create.
However with the above export file the root user on hwnode1 can directly mount /virtual_machines/kvm/export and see everything, even the files that were for hwnode2 only.
OTOH if I set my fsid=0 line so that it's not mountable (e.g. changing the IP or netmask), all lines below it stop working.

How should I do?

Thanks for your help

Recent distros allow you to specify NFSv4 exports as you do NFSv2/v3 exports, without the need for the explicit fsid=0 export. I think that will eliminate the problem you're seeing.

However, I'd strongly recommend against use of subtree_check, which can cause unnecessary ESTALE's when files are renamed.

It would be better to put hwnode1 and hwnode2 on different filesystems.

--b.