Fix do_path_lookup() to avoid accessing invalid dentry or inode when the
link_path_walk() has failed.  This should fix Bugme #5897.
Signed-off-by: NSuzuki K P <suzuki@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>