From: Badari Pulavarty <pbadari@us.ibm.com>

I found the problem with O_DIRECT memory leak.

The problem is, when we are doing DIO read and crossed the end of file - we
don't release referencess on all the pages we got from get_user_pages().
(since it is a success case).

The fix is to call dio_cleanup() even for sucess cases.