diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 54df209..bde9d0b 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -23,6 +23,7 @@
 
 #include "mballoc.h"
 #include <linux/debugfs.h>
+#include <linux/slab.h>
 #include <trace/events/ext4.h>
 
 /*