diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index d8c2414..b06ab1f 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -111,7 +111,8 @@
 	__u8 encrypt_pw_salt[16];	/* Salt used for string2key algorithm */
 	struct f2fs_device devs[MAX_DEVICES];	/* device list */
 	__le32 qf_ino[F2FS_MAX_QUOTAS];	/* quota inode numbers */
-	__u8 reserved[315];		/* valid reserved region */
+	__u8 hot_ext_count;		/* # of hot file extension */
+	__u8 reserved[314];		/* valid reserved region */
 } __packed;
 
 /*