diff --git a/fs/libfs.c b/fs/libfs.c
index f6d411e..5b2dbb3 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -12,7 +12,7 @@
 #include <linux/mutex.h>
 #include <linux/exportfs.h>
 #include <linux/writeback.h>
-#include <linux/buffer_head.h>
+#include <linux/buffer_head.h> /* sync_mapping_buffers */
 
 #include <asm/uaccess.h>