[Unionfs] Can't mount NFS-exported union anymore in unionfs-1.4

[hooanon05 at yahoo.co.jp]

Wilhelm Meier:
> But if I try to use the nfs-exported union as a root-fs for another machine I 
> get on the other machine:
> 
> nfs_stat_to_errno: bad nfs status return value: 45
> 
> Hints?

Unfortunately I cannot give you any hints currently.
- Do you use imap option for unionfs on your NFS server? It is required.
- Did you write something to your unionfs after your NFS clients mounted
  it? You have written your unionfs gentoo_B is exported as readonly, so
  if you write, it must be done on your NFS server.
- Does your 45 mean NFSERR_OPNOTSUPP? Do you know what operation you
  did? Can you use strace or something to find which systemcall retruns
  the error on NFS client?

Junjiro Okajima