Hi,
      The vnode/vfs code prevents opening of device special files if it is 
     mounted or prevents mounting of the file if it has been opened. 
     However consider the case where 2 different file names either on the 
     same filesystem or different filesystem map to the same device. If 
     these files are opened, the read/write will be cached through their 
     repective vnode's with unpredictable results. Is this correct ?. I 
     haven't seen anything in the code that would preclude this situation.
     What does checkaliases() do?
     
     Thanks for your responses.
     
     kanchan