title: NFS cache-cleaning command?
body: <p>I have a trouble with NFS client-side attribute caching.
  I'm using some servers, one is an NFS server and the others are NFS client servers.</p>
  
  <p>All servers are Debian(lenny, 2.6.26-2-amd64 of Linux) and versions are following.</p>
  
  <pre><code> % dpkg -l | grep nfs
  ii  libnfsidmap2                        0.20-1                     An nfs idmapping library
  ii  nfs-common                          1:1.1.2-6lenny1            NFS support files common to client and server
  ii  nfs-kernel-server                   1:1.1.2-6lenny1            support for NFS kernel server
  </code></pre>
  
  <p>In the NFS server, /etc/exports is written as following:</p>
  
  <pre><code>/export-path   192.168.0.0/255.255.255.0(async,rw,no_subtree_check)
  </code></pre>
  
  <p>In the NFS clients, /etc/fstab is written as following:</p>
  
  <pre><code>server:/export-path     /mountpoint   nfs rw,hard,intr,rsize=8192,async 0 0
  </code></pre>
  
  <p>As you can see, "async" option is used for multi-clients access performance.
  However, sometimes this can cause false-caching errors.</p>
  
  <p>Since I am maintaining many servers (and I have not so strong permission to change the mount options), I don't want to modify /etc/exports nor /etc/fstab.
  I think it is sufficient if I have a command-line tool that "cleans" NFS client-side attribute cache with a user permission.</p>
  
  <p>Please let me know if there such commands.</p>
  
  <p>Thanks,</p>
  
  <p><hr>
  (Appended)</p>
  
  <p>I mean by "false-caching errors",</p>
  
  <pre><code> % ls -l /data/1/kabe/foo                  
  ls: cannot access /data/1/kabe/foo: No such file or directory
   % ssh another-server 'touch /data/1/kabe/foo' 
   % ls -l /data/1/kabe/foo
  ls: cannot access /data/1/kabe/foo: No such file or directory
  </code></pre>
  
  <p>Sometimes such cases happen.
  The problem is not a file content but file attributes(=dentries information) since NFS says it guarantees Close-to-Open consistency.</p>