f2fs: free radix_tree_nodes used by nat_set entries

In the normal case, the radix_tree_nodes are freed successfully.
But, when cp_error was detected, we should destroy them forcefully.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index cac8a3d..f405bbf 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -25,6 +25,7 @@
 
 /* vector size for gang look-up from nat cache that consists of radix tree */
 #define NATVEC_SIZE	64
+#define SETVEC_SIZE	32
 
 /* return value for read_node_page */
 #define LOCKED_PAGE	1