NFSv4: Ensure that we track the NFSv4 lock state in read/write requests.

This patch fixes bugzilla entry 14501:
  https://bugzilla.kernel.org/show_bug.cgi?id=14501

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index 3c60685..f8b60e7 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -39,6 +39,7 @@
 	struct list_head	wb_list;	/* Defines state of page: */
 	struct page		*wb_page;	/* page to read in/write out */
 	struct nfs_open_context	*wb_context;	/* File state context info */
+	struct nfs_lock_context	*wb_lock_context;	/* lock context info */
 	atomic_t		wb_complete;	/* i/os we're waiting for */
 	pgoff_t			wb_index;	/* Offset >> PAGE_CACHE_SHIFT */
 	unsigned int		wb_offset,	/* Offset & ~PAGE_CACHE_MASK */