• Suresh Jayaraman's avatar
    NFS: Handle -ESTALE error in access() · a71ee337
    Suresh Jayaraman authored
    Hi Trond,
    
    I have been looking at a bugreport where trying to open applications on KDE
    on a NFS mounted home fails temporarily. There have been multiple reports on
    different kernel versions pointing to this common issue:
    http://bugzilla.kernel.org/show_bug.cgi?id=12557
    https://bugs.launchpad.net/ubuntu/+source/linux/+bug/269954
    http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=508866.html
    
    This issue can be reproducible consistently by doing this on a NFS mounted
    home (KDE):
    1. Open 2 xterm sessions
    2. From one of the xterm session, do "ssh -X <remote host>"
    3. "stat ~/.Xauthority" on the remote SSH session
    4. Close the two xterm sessions
    5. On the server do a "stat ~/.Xauthority"
    6. Now on the client, try to open xterm
    This will fail.
    
    Even if the filehandle had become stale, the NFS client should invalidate
    the cache/inode and should repeat LOOKUP. Looking at the packet capture when
    the failure occurs shows that there were two subsequent ACCESS() calls with
    the same filehandle and both fails with -ESTALE error.
    
    I have tested the fix below. Now the client issue a LOOKUP after the
    ACCESS() call fails with -ESTALE. If all this makes sense to you, can you
    consider this for inclusion?
    
    Thanks,
    
    
    If the server returns an -ESTALE error due to stale filehandle in response to
    an ACCESS() call, we need to invalidate the cache and inode so that LOOKUP()
    can be retried. Without this change, the nfs client retries ACCESS() with the
    same filehandle, fails again and could lead to temporary failure of
    applications running on nfs mounted home.
    Signed-off-by: default avatarSuresh Jayaraman <sjayaraman@suse.de>
    Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
    a71ee337
dir.c 52.4 KB