[CentOS] NFSv4: Using fsid=0 but *not* exporting the root filesystem

Thu Mar 28 18:50:59 UTC 2019
Frank Thommen <list.centos at drosera.ch>

Hi,

I would like to use the NFSv4 ability to create a "root" filesystem with 
fsid=0, so that I don't have to refer to the whole path of the exported 
filesystem when I mount it.  However I do *not* want this root 
filesystem to be mountable by any host.  Is that possible and how?

E.g
Filesystem:
   /exports/data1
   /exports/data2
   /exports/data3

/etc/exports:
   /exports         *(ro,no_subtree_check,fsid=0)
   /exports/data1   host1(rw)
   /exports/data2   host1(rw)
   /exports/data3   host2(rw)


host1 and host2 can mount fileserver:/ and access any of the dataN 
directories at least read-only.  That is unwanted.  I'd like 
/exports/data1 and /exports/data2 to be exclusively accessible by host1 
and /exports/data3 by host2.  But I'd still like to be able to mount 
e.f. as fileserver:/data1 instead of fileserver:/exports/data1.

I've search around a lot and I have found the question several times, 
but no solution yet.

Cheers
frank