Introduce several fsstack_copy_* functions which allow stackable filesystems
(such as eCryptfs and Unionfs) to easily copy over (currently only) inode
attributes.  This prevents code duplication and allows for code reuse.

[akpm@osdl.org: Remove unneeded wrapper]
[bunk@stusta.de: fs/stack.c should #include <linux/fs_stack.h>]
Signed-off-by: NJosef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>