staging/lustre/llite: Add exception entry check after radix_tree

We need to check for an exception entry after radix_tree lookup.
Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Reviewed-on: http://review.whamcloud.com/10709
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5162Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/dir.c

@@ -278,7 +278,7 @@ static struct page *ll_dir_page_locate(struct inode *dir, __u64 *hash,
 	spin_lock_irq(&mapping->tree_lock);
 	found = radix_tree_gang_lookup(&mapping->page_tree,
 				       (void **)&page, offset, 1);
-	if (found > 0) {
+	if (found > 0 && !radix_tree_exceptional_entry(page)) {
 		struct lu_dirpage *dp;
 
 		page_cache_get(page);