diff -drupN a/fs/yaffs2/yaffs_linux.h b/fs/yaffs2/yaffs_linux.h
--- a/fs/yaffs2/yaffs_linux.h	1970-01-01 03:00:00.000000000 +0300
+++ b/fs/yaffs2/yaffs_linux.h	2022-06-09 05:02:35.000000000 +0300
@@ -0,0 +1,47 @@
+/*
+ * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2018 Aleph One Ltd.
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
+ */
+
+#ifndef __YAFFS_LINUX_H__
+#define __YAFFS_LINUX_H__
+
+#include "yportenv.h"
+
+struct yaffs_linux_context {
+	struct list_head context_list;	/* List of these we have mounted */
+	struct yaffs_dev *dev;
+	struct super_block *super;
+	struct task_struct *bg_thread;	/* Background thread for this device */
+	int bg_running;
+	struct mutex gross_lock;	/* Gross locking mutex*/
+	u8 *spare_buffer;	/* For mtdif2 use. Don't know the buffer size
+				 * at compile time so we have to allocate it.
+				 */
+	struct list_head search_contexts;
+	struct task_struct *readdir_process;
+	unsigned mount_id;
+	int dirty;
+};
+
+#define yaffs_dev_to_lc(dev) ((struct yaffs_linux_context *)((dev)->os_context))
+#define yaffs_dev_to_mtd(dev) ((struct mtd_info *)((dev)->driver_context))
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+#define WRITE_SIZE_STR "writesize"
+#define WRITE_SIZE(mtd) ((mtd)->writesize)
+#else
+#define WRITE_SIZE_STR "oobblock"
+#define WRITE_SIZE(mtd) ((mtd)->oobblock)
+#endif
+
+#endif