diff --git a/fs/befs/debug.c b/fs/befs/debug.c
new file mode 100644
index 0000000..eb7bd6c
--- /dev/null
+++ b/fs/befs/debug.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/befs/debug.c
+ *
+ * Copyright (C) 2001 Will Dyson (will_dyson at pobox.com)
+ *
+ * With help from the ntfs-tng driver by Anton Altparmakov
+ *
+ * Copyright (C) 1999  Makoto Kato (m_kato@ga2.so-net.ne.jp)
+ *
+ * debug functions
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#ifdef __KERNEL__
+
+#include <stdarg.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+
+#endif				/* __KERNEL__ */
+
+#include "befs.h"
+
+void
+befs_error(const struct super_block *sb, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	pr_err("(%s): %pV\n", sb->s_id, &vaf);
+	va_end(args);
+}
+
+void
+befs_warning(const struct super_block *sb, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	pr_warn("(%s): %pV\n", sb->s_id, &vaf);
+	va_end(args);
+}
+
+void
+befs_debug(const struct super_block *sb, const char *fmt, ...)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	pr_debug("(%s): %pV\n", sb->s_id, &vaf);
+	va_end(args);
+
+#endif				//CONFIG_BEFS_DEBUG
+}
+
+void
+befs_dump_inode(const struct super_block *sb, befs_inode *inode)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	befs_block_run tmp_run;
+
+	befs_debug(sb, "befs_inode information");
+
+	befs_debug(sb, "  magic1 %08x", fs32_to_cpu(sb, inode->magic1));
+
+	tmp_run = fsrun_to_cpu(sb, inode->inode_num);
+	befs_debug(sb, "  inode_num %u, %hu, %hu",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+	befs_debug(sb, "  uid %u", fs32_to_cpu(sb, inode->uid));
+	befs_debug(sb, "  gid %u", fs32_to_cpu(sb, inode->gid));
+	befs_debug(sb, "  mode %08x", fs32_to_cpu(sb, inode->mode));
+	befs_debug(sb, "  flags %08x", fs32_to_cpu(sb, inode->flags));
+	befs_debug(sb, "  create_time %llu",
+		   fs64_to_cpu(sb, inode->create_time));
+	befs_debug(sb, "  last_modified_time %llu",
+		   fs64_to_cpu(sb, inode->last_modified_time));
+
+	tmp_run = fsrun_to_cpu(sb, inode->parent);
+	befs_debug(sb, "  parent [%u, %hu, %hu]",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+	tmp_run = fsrun_to_cpu(sb, inode->attributes);
+	befs_debug(sb, "  attributes [%u, %hu, %hu]",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+	befs_debug(sb, "  type %08x", fs32_to_cpu(sb, inode->type));
+	befs_debug(sb, "  inode_size %u", fs32_to_cpu(sb, inode->inode_size));
+
+	if (S_ISLNK(fs32_to_cpu(sb, inode->mode))) {
+		befs_debug(sb, "  Symbolic link [%s]", inode->data.symlink);
+	} else {
+		int i;
+
+		for (i = 0; i < BEFS_NUM_DIRECT_BLOCKS; i++) {
+			tmp_run =
+			    fsrun_to_cpu(sb, inode->data.datastream.direct[i]);
+			befs_debug(sb, "  direct %d [%u, %hu, %hu]", i,
+				   tmp_run.allocation_group, tmp_run.start,
+				   tmp_run.len);
+		}
+		befs_debug(sb, "  max_direct_range %llu",
+			   fs64_to_cpu(sb,
+				       inode->data.datastream.
+				       max_direct_range));
+
+		tmp_run = fsrun_to_cpu(sb, inode->data.datastream.indirect);
+		befs_debug(sb, "  indirect [%u, %hu, %hu]",
+			   tmp_run.allocation_group,
+			   tmp_run.start, tmp_run.len);
+
+		befs_debug(sb, "  max_indirect_range %llu",
+			   fs64_to_cpu(sb,
+				       inode->data.datastream.
+				       max_indirect_range));
+
+		tmp_run =
+		    fsrun_to_cpu(sb, inode->data.datastream.double_indirect);
+		befs_debug(sb, "  double indirect [%u, %hu, %hu]",
+			   tmp_run.allocation_group, tmp_run.start,
+			   tmp_run.len);
+
+		befs_debug(sb, "  max_double_indirect_range %llu",
+			   fs64_to_cpu(sb,
+				       inode->data.datastream.
+				       max_double_indirect_range));
+
+		befs_debug(sb, "  size %llu",
+			   fs64_to_cpu(sb, inode->data.datastream.size));
+	}
+
+#endif				//CONFIG_BEFS_DEBUG
+}
+
+/*
+ * Display super block structure for debug.
+ */
+
+void
+befs_dump_super_block(const struct super_block *sb, befs_super_block *sup)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	befs_block_run tmp_run;
+
+	befs_debug(sb, "befs_super_block information");
+
+	befs_debug(sb, "  name %s", sup->name);
+	befs_debug(sb, "  magic1 %08x", fs32_to_cpu(sb, sup->magic1));
+	befs_debug(sb, "  fs_byte_order %08x",
+		   fs32_to_cpu(sb, sup->fs_byte_order));
+
+	befs_debug(sb, "  block_size %u", fs32_to_cpu(sb, sup->block_size));
+	befs_debug(sb, "  block_shift %u", fs32_to_cpu(sb, sup->block_shift));
+
+	befs_debug(sb, "  num_blocks %llu", fs64_to_cpu(sb, sup->num_blocks));
+	befs_debug(sb, "  used_blocks %llu", fs64_to_cpu(sb, sup->used_blocks));
+	befs_debug(sb, "  inode_size %u", fs32_to_cpu(sb, sup->inode_size));
+
+	befs_debug(sb, "  magic2 %08x", fs32_to_cpu(sb, sup->magic2));
+	befs_debug(sb, "  blocks_per_ag %u",
+		   fs32_to_cpu(sb, sup->blocks_per_ag));
+	befs_debug(sb, "  ag_shift %u", fs32_to_cpu(sb, sup->ag_shift));
+	befs_debug(sb, "  num_ags %u", fs32_to_cpu(sb, sup->num_ags));
+
+	befs_debug(sb, "  flags %08x", fs32_to_cpu(sb, sup->flags));
+
+	tmp_run = fsrun_to_cpu(sb, sup->log_blocks);
+	befs_debug(sb, "  log_blocks %u, %hu, %hu",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+	befs_debug(sb, "  log_start %lld", fs64_to_cpu(sb, sup->log_start));
+	befs_debug(sb, "  log_end %lld", fs64_to_cpu(sb, sup->log_end));
+
+	befs_debug(sb, "  magic3 %08x", fs32_to_cpu(sb, sup->magic3));
+
+	tmp_run = fsrun_to_cpu(sb, sup->root_dir);
+	befs_debug(sb, "  root_dir %u, %hu, %hu",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+	tmp_run = fsrun_to_cpu(sb, sup->indices);
+	befs_debug(sb, "  indices %u, %hu, %hu",
+		   tmp_run.allocation_group, tmp_run.start, tmp_run.len);
+
+#endif				//CONFIG_BEFS_DEBUG
+}
+
+#if 0
+/* unused */
+void
+befs_dump_small_data(const struct super_block *sb, befs_small_data *sd)
+{
+}
+
+/* unused */
+void
+befs_dump_run(const struct super_block *sb, befs_disk_block_run run)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	befs_block_run n = fsrun_to_cpu(sb, run);
+
+	befs_debug(sb, "[%u, %hu, %hu]", n.allocation_group, n.start, n.len);
+
+#endif				//CONFIG_BEFS_DEBUG
+}
+#endif  /*  0  */
+
+void
+befs_dump_index_entry(const struct super_block *sb,
+		      befs_disk_btree_super *super)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	befs_debug(sb, "Btree super structure");
+	befs_debug(sb, "  magic %08x", fs32_to_cpu(sb, super->magic));
+	befs_debug(sb, "  node_size %u", fs32_to_cpu(sb, super->node_size));
+	befs_debug(sb, "  max_depth %08x", fs32_to_cpu(sb, super->max_depth));
+
+	befs_debug(sb, "  data_type %08x", fs32_to_cpu(sb, super->data_type));
+	befs_debug(sb, "  root_node_pointer %016LX",
+		   fs64_to_cpu(sb, super->root_node_ptr));
+	befs_debug(sb, "  free_node_pointer %016LX",
+		   fs64_to_cpu(sb, super->free_node_ptr));
+	befs_debug(sb, "  maximum size %016LX",
+		   fs64_to_cpu(sb, super->max_size));
+
+#endif				//CONFIG_BEFS_DEBUG
+}
+
+void
+befs_dump_index_node(const struct super_block *sb, befs_btree_nodehead *node)
+{
+#ifdef CONFIG_BEFS_DEBUG
+
+	befs_debug(sb, "Btree node structure");
+	befs_debug(sb, "  left %016LX", fs64_to_cpu(sb, node->left));
+	befs_debug(sb, "  right %016LX", fs64_to_cpu(sb, node->right));
+	befs_debug(sb, "  overflow %016LX", fs64_to_cpu(sb, node->overflow));
+	befs_debug(sb, "  all_key_count %hu",
+		   fs16_to_cpu(sb, node->all_key_count));
+	befs_debug(sb, "  all_key_length %hu",
+		   fs16_to_cpu(sb, node->all_key_length));
+
+#endif				//CONFIG_BEFS_DEBUG
+}