diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 052f214..38a0a99 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/pagemap.h>
+#include <linux/slab.h>
 #include <linux/log2.h>
 
 #include "btree.h"