Description of problem:

 What?
    =====
    
    * files can be accessed directly through their gfid and not just
      through their paths. For eg., if the gfid of a file is
      f3142503-c75e-45b1-b92a-463cf4c01f99, that file can be accessed
      using <gluster-mount>/.gfid-path/f3142503-c75e-45b1-b92a-463cf4c01f99
    
      .gfid-path is a virtual directory used to seperate out the namespace
      for accessing files through gfid. This way, we do not conflict with
      filenames which can be qualified as uuids.
    
    * A new file/directory/symlink can be created with a pre-specified
      gfid.
    
      gfids can be specified through process environment variables
      GLUSTERFS_GFID or GLUSTERFS_GFID_<thread-id>. The latter syntax
      helps to concurrently create files from a multithreaded application.
    
      For eg.,
      bash# GLUSTERFS_GFID=<gfid-of-new-file>
            touch /mnt/glusterfs/.gfid-path/<par-gfid>/testfile
    
      will create 'testfile' under par-gfid path, with <gfid-of-new-file>.
    
    Why?
    ====
       
    * An initial consumer of this feature would be geo-replication to
      create files on slave mount with same gfids as that on master.
      It will also help gsyncd to access files directly through their
      gfids. gsyncd in its newer version will be consuming a changelog
      (of master) containing operations on gfids and sync corresponding
      files to slave.
 

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