NFS and no_root_squash - cannot write as root - permission denied

[Jari Aalto <jari.aalto@cante.net>]

Can anyone suggest what might be wrong as root user cannot write to the
NFS mounted directory.

At client, the mount succeeds, but write doesn't. The 'no_root_squash'
is enabled at server, the UUID's match, so where is the problem[1]?.

Jari

AT CLIENT (192.168.1.12 / Debian unstable)

  $ dpkg -l nfs-common
    ii  nfs-common            1:1.1.3-1

  $ mount 192.168.1.7:/mnt/local/storage/share/src /mnt/tmp
    <ok, no errors>

  $ mount | grep 1.7
    192.168.1.7:/mnt/local/storage/share/src on /mnt/tmp type nfs (rw,addr=192.168.1.7)

  $ ls -l /mnt/tmp
    drwxrwsr-x  4 root src  4096 2008-08-24 20:28 .

  $ id -a
    uid=0(root) gid=0(root) groups=0(root)

  $ touch /mnt/tmp/test.tmp
    touch: cannot touch `/mnt/tmp/test.tmp': Permission denied

AT SERVER (192.168.1.7 / Debian testing)

- Version

  $ dpkg -l nfs-kernel-server
  ii  nfs-kernel-server     1:1.1.2-6

- /etc/exports contains 'no_root_squash' which should allow root access

  /mnt/local/storage/share/src 192.168.1.0/27(rw,sync,no_root_squash,no_subtree_check)

- How Kernel sees the exports (after "exportfs -rav"):

  $ cat /proc/fs/nfs/exports
  # Version 1.1
  # Path Client(Flags) # IPs
  /mnt/local/storage/share/src    192.168.1.0/27(rw,no_root_squash,sync,wdelay,no_subtree_check,uuid=d16a2f42:9a504489:a7888624:c832a7f3)

   $ showmount -e  | grep src
   /mnt/local/storage/share/src 192.168.1.0/27

- identity and write test

  $ id -a
  uid=0(root) gid=0(root) groups=0(root)

  $ touch /mnt/local/storage/share/src/test.tmp
  $ ls -la  /mnt/local/storage/share/src/test.tmp
    -rw-r--r-- 1 root src 0 2008-08-24 20:52 /mnt/local/storage/share/src/test.tmp
  $ rm  /mnt/local/storage/share/src/test.tmp

- Directory permissions

  $ ls -la /mnt/local/storage/share/src
  drwxrwsr-x  4 root src  4096 2008-08-24 20:28 .

- No service restrictions

  $ cat /etc/hosts.allow
  <empty>

  $ cat /etc/hosts.deny
  <empty>

- No firewalls

  $ iptables -L
  Chain INPUT (policy ACCEPT)
  target     prot opt source               destination         

  Chain FORWARD (policy ACCEPT)
  target     prot opt source               destination         

  Chain OUTPUT (policy ACCEPT)
  target     prot opt source               destination        

[1]
I've read all of this, but it doesn't explain what's missing here.

    "I do not have permission to access files on the mounted volume"
    http://nfs.sourceforge.net/nfs-howto/ar01s07.html