DFS feature support

configname: CONFIG_CIFS_DFS_UPCALL

Linux Kernel Configuration
└─>File systems
└─>Network File Systems
└─>DFS feature support
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
Distributed File System (DFS) support is used to access shares
transparently in an enterprise name space, even if the share
moves to a different server. This feature also enables
an upcall mechanism for CIFS which contacts userspace helper
utilities to provide server name resolution (host names to
IP addresses) which is needed for implicit mounts of DFS junction
points. If unsure, say N.