"mount: File exists" when trying to mount a second NFS4/krb5 shares

[Trond Myklebust]

On Sat, 2006-10-21 at 15:02 +0200, Joachim Selke wrote:
> Hi,
> 
> I have a strange problem using NFS4 shares with krb5 security flavor.
> 
> My server is running Fedora Core 5 (Kernel 2.6.18-1) and offers NFS
> shares to clients. My /etc/exports is:
> 
> /export             gss/krb5(fsid=0,rw,insecure,no_subtree_check,sync)
> /export/home        gss/krb5(rw,nohide,insecure,no_subtree_check,sync)
> /export/thi-shared  gss/krb5(rw,nohide,insecure,no_subtree_check,sync)
> 
> Both /export/home and /export/thi-shared are mounted via bind.
> /etc/fstab contains the following lines:
> 
> /home       /export/home       none bind 0 0
> /thi-shared /export/thi-shared none bind 0 0
> 
> Now I try to mount these shares on some client:
> mount -v -t nfs4 -o sec=krb5 MYSERVER:/thi-shared /import/thi-shared
> 
> That works fine. I get the following output:
> 
> mount: pinging: prog 100003 vers 4 prot tcp port 2049
> MYSERVER:/thi-shared on /import/thi-shared type nfs4
> (rw,sec=krb5,addr=MYSERVERIP)
> 
> But then I try to mount the other share:
> mount -v -t nfs4 -o sec=krb5 MYSERVER:/home /import/home
> 
> That fails and I get the following output:
> 
> mount: pinging: prog 100003 vers 4 prot tcp port 2049
> mount: File exists
> 
> If I try to mount home first and then thi-shared I get the same problem:
> The first command succeeds, the second fails.
> 
> Can anybody give me a hint what's going wrong? How can I get more debug
> information?

Why are you doing this in the first place? If you use nohide, then it
should be quite unnecessary to do the above since that tells the server
to allow your client to transparently cross the mountpoint.

In fact, the reason why you are seeing an EEXIST error there, is very
likely to be because the 2.6.18 kernel on your client has already
automounted it for you: 'cat /proc/mounts'.

Cheers,
  Trond