[PATCH] autofs4: readdir fixes

[PATCH] autofs4: readdir fixes

From: Ian Kent <raven@themaw.net>

a. Implement readdir and friends for directory lookup for late mounting.
   This is done largely by replacing a catch all condition in
   try_to_fill_dentry with appropriate cases.

b. Add path calc.  function in waitq.c to get extended path to return to
   daemon (for direct mounts).

c. Add revalidate calls to sys_chdir and sys_chroot so that pwd lookups
   work correctly.

d. Add ioctl to retrieve minor version for automount daemon (and me) to
   recognise module fix level.  Bumped minor version to 5.

From: Hugh Dickins <hugh@veritas.com>

  After chdir (or chroot) to non-existent directory on 2.6.5-mm5, you can no
  longer unmount filesystem holding working directory (or root).