diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 163c445..922d187 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -790,6 +790,8 @@
 #define	EXT4_DEF_RESUID		0
 #define	EXT4_DEF_RESGID		0
 
+#define EXT4_DEF_INODE_READAHEAD_BLKS	32
+
 /*
  * Default mount options
  */