diff --git a/Makefile.in b/Makefile.in
index fcc64030..de409ba8 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -403,14 +403,15 @@ btrfs-image.static: $(static_objects) image/main.static.o $(static_libbtrfs_obje
 	$(Q)$(CC) $(STATIC_CFLAGS) -o $@ image/main.static.o $(static_objects) \
 		$(static_libbtrfs_objects) $(STATIC_LDFLAGS) $(STATIC_LIBS)
 
-btrfs-convert: $(objects) $(libs_static) convert/main.o
+btrfs-convert: $(objects) $(libs_static) convert/main.o convert/common.o
 	@echo "    [LD]     $@"
-	$(Q)$(CC) $(CFLAGS) -I$(TOPDIR)/convert -o btrfs-convert $(objects) convert/main.o $(libs_static) \
+	$(Q)$(CC) $(CFLAGS) -I$(TOPDIR)/convert -o btrfs-convert $(objects) \
+		convert/main.o convert/common.o $(libs_static) \
 		$(LDFLAGS) $(btrfs_convert_libs) $(LIBS)
 
-btrfs-convert.static: $(static_objects) convert/main.static.o $(static_libbtrfs_objects)
+btrfs-convert.static: $(static_objects) convert/main.static.o convert/common.static.o $(static_libbtrfs_objects)
 	@echo "    [LD]     $@"
-	$(Q)$(CC) $(STATIC_CFLAGS) -o $@ convert/main.static.o $(static_objects) \
+	$(Q)$(CC) $(STATIC_CFLAGS) -o $@ convert/main.static.o convert/common.static.o $(static_objects) \
 		$(static_libbtrfs_objects) $(STATIC_LDFLAGS) $(btrfs_convert_libs) $(STATIC_LIBS)
 
 dir-test: $(objects) $(libs) dir-test.o
diff --git a/convert/common.c b/convert/common.c
new file mode 100644
index 00000000..7a9b5962
--- /dev/null
+++ b/convert/common.c
@@ -0,0 +1,882 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <unistd.h>
+#include <uuid/uuid.h>
+#include "disk-io.h"
+#include "volumes.h"
+#include "utils.h"
+#include "mkfs/common.h"
+#include "convert/common.h"
+
+/*
+ * Reserve space from free_tree.
+ * The algorithm is very simple, find the first cache_extent with enough space
+ * and allocate from its beginning.
+ */
+static int reserve_free_space(struct cache_tree *free_tree, u64 len,
+			      u64 *ret_start)
+{
+	struct cache_extent *cache;
+	int found = 0;
+
+	ASSERT(ret_start != NULL);
+	cache = first_cache_extent(free_tree);
+	while (cache) {
+		if (cache->size > len) {
+			found = 1;
+			*ret_start = cache->start;
+
+			cache->size -= len;
+			if (cache->size == 0) {
+				remove_cache_extent(free_tree, cache);
+				free(cache);
+			} else {
+				cache->start += len;
+			}
+			break;
+		}
+		cache = next_cache_extent(cache);
+	}
+	if (!found)
+		return -ENOSPC;
+	return 0;
+}
+
+static inline int write_temp_super(int fd, struct btrfs_super_block *sb,
+                                  u64 sb_bytenr)
+{
+       u32 crc = ~(u32)0;
+       int ret;
+
+       crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
+                             BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+       btrfs_csum_final(crc, &sb->csum[0]);
+       ret = pwrite(fd, sb, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
+       if (ret < BTRFS_SUPER_INFO_SIZE)
+               ret = (ret < 0 ? -errno : -EIO);
+       else
+               ret = 0;
+       return ret;
+}
+
+/*
+ * Setup temporary superblock at cfg->super_bynter
+ * Needed info are extracted from cfg, and root_bytenr, chunk_bytenr
+ *
+ * For now sys chunk array will be empty and dev_item is empty too.
+ * They will be re-initialized at temp chunk tree setup.
+ *
+ * The superblock signature is not valid, denotes a partially created
+ * filesystem, needs to be finalized.
+ */
+static int setup_temp_super(int fd, struct btrfs_mkfs_config *cfg,
+			    u64 root_bytenr, u64 chunk_bytenr)
+{
+	unsigned char chunk_uuid[BTRFS_UUID_SIZE];
+	char super_buf[BTRFS_SUPER_INFO_SIZE];
+	struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
+	int ret;
+
+	memset(super_buf, 0, BTRFS_SUPER_INFO_SIZE);
+	cfg->num_bytes = round_down(cfg->num_bytes, cfg->sectorsize);
+
+	if (*cfg->fs_uuid) {
+		if (uuid_parse(cfg->fs_uuid, super->fsid) != 0) {
+			error("cound not parse UUID: %s", cfg->fs_uuid);
+			ret = -EINVAL;
+			goto out;
+		}
+		if (!test_uuid_unique(cfg->fs_uuid)) {
+			error("non-unique UUID: %s", cfg->fs_uuid);
+			ret = -EINVAL;
+			goto out;
+		}
+	} else {
+		uuid_generate(super->fsid);
+		uuid_unparse(super->fsid, cfg->fs_uuid);
+	}
+	uuid_generate(chunk_uuid);
+	uuid_unparse(chunk_uuid, cfg->chunk_uuid);
+
+	btrfs_set_super_bytenr(super, cfg->super_bytenr);
+	btrfs_set_super_num_devices(super, 1);
+	btrfs_set_super_magic(super, BTRFS_MAGIC_PARTIAL);
+	btrfs_set_super_generation(super, 1);
+	btrfs_set_super_root(super, root_bytenr);
+	btrfs_set_super_chunk_root(super, chunk_bytenr);
+	btrfs_set_super_total_bytes(super, cfg->num_bytes);
+	/*
+	 * Temporary filesystem will only have 6 tree roots:
+	 * chunk tree, root tree, extent_tree, device tree, fs tree
+	 * and csum tree.
+	 */
+	btrfs_set_super_bytes_used(super, 6 * cfg->nodesize);
+	btrfs_set_super_sectorsize(super, cfg->sectorsize);
+	btrfs_set_super_leafsize(super, cfg->nodesize);
+	btrfs_set_super_nodesize(super, cfg->nodesize);
+	btrfs_set_super_stripesize(super, cfg->stripesize);
+	btrfs_set_super_csum_type(super, BTRFS_CSUM_TYPE_CRC32);
+	btrfs_set_super_chunk_root(super, chunk_bytenr);
+	btrfs_set_super_cache_generation(super, -1);
+	btrfs_set_super_incompat_flags(super, cfg->features);
+	if (cfg->label)
+		__strncpy_null(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
+
+	/* Sys chunk array will be re-initialized at chunk tree init time */
+	super->sys_chunk_array_size = 0;
+
+	ret = write_temp_super(fd, super, cfg->super_bytenr);
+out:
+	return ret;
+}
+
+static int setup_temp_extent_buffer(struct extent_buffer *buf,
+				    struct btrfs_mkfs_config *cfg,
+				    u64 bytenr, u64 owner)
+{
+	unsigned char fsid[BTRFS_FSID_SIZE];
+	unsigned char chunk_uuid[BTRFS_UUID_SIZE];
+	int ret;
+
+	ret = uuid_parse(cfg->fs_uuid, fsid);
+	if (ret)
+		return -EINVAL;
+	ret = uuid_parse(cfg->chunk_uuid, chunk_uuid);
+	if (ret)
+		return -EINVAL;
+
+	memset(buf->data, 0, cfg->nodesize);
+	buf->len = cfg->nodesize;
+	btrfs_set_header_bytenr(buf, bytenr);
+	btrfs_set_header_generation(buf, 1);
+	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
+	btrfs_set_header_owner(buf, owner);
+	btrfs_set_header_flags(buf, BTRFS_HEADER_FLAG_WRITTEN);
+	write_extent_buffer(buf, chunk_uuid, btrfs_header_chunk_tree_uuid(buf),
+			    BTRFS_UUID_SIZE);
+	write_extent_buffer(buf, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
+	return 0;
+}
+
+static void insert_temp_root_item(struct extent_buffer *buf,
+				  struct btrfs_mkfs_config *cfg,
+				  int *slot, u32 *itemoff, u64 objectid,
+				  u64 bytenr)
+{
+	struct btrfs_root_item root_item;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_disk_key disk_key;
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	(*itemoff) -= sizeof(root_item);
+	memset(&root_item, 0, sizeof(root_item));
+	inode_item = &root_item.inode;
+	btrfs_set_stack_inode_generation(inode_item, 1);
+	btrfs_set_stack_inode_size(inode_item, 3);
+	btrfs_set_stack_inode_nlink(inode_item, 1);
+	btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
+	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
+	btrfs_set_root_refs(&root_item, 1);
+	btrfs_set_root_used(&root_item, cfg->nodesize);
+	btrfs_set_root_generation(&root_item, 1);
+	btrfs_set_root_bytenr(&root_item, bytenr);
+
+	memset(&disk_key, 0, sizeof(disk_key));
+	btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
+	btrfs_set_disk_key_objectid(&disk_key, objectid);
+	btrfs_set_disk_key_offset(&disk_key, 0);
+
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(root_item));
+	write_extent_buffer(buf, &root_item,
+			    btrfs_item_ptr_offset(buf, *slot),
+			    sizeof(root_item));
+	(*slot)++;
+}
+
+/*
+ * Setup an extent buffer for tree block.
+ */
+static inline int write_temp_extent_buffer(int fd, struct extent_buffer *buf,
+					   u64 bytenr)
+{
+	int ret;
+
+	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
+
+	/* Temporary extent buffer is always mapped 1:1 on disk */
+	ret = pwrite(fd, buf->data, buf->len, bytenr);
+	if (ret < buf->len)
+		ret = (ret < 0 ? ret : -EIO);
+	else
+		ret = 0;
+	return ret;
+}
+
+static int setup_temp_root_tree(int fd, struct btrfs_mkfs_config *cfg,
+				u64 root_bytenr, u64 extent_bytenr,
+				u64 dev_bytenr, u64 fs_bytenr, u64 csum_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+	int slot = 0;
+	int ret;
+
+	/*
+	 * Provided bytenr must in ascending order, or tree root will have a
+	 * bad key order.
+	 */
+	if (!(root_bytenr < extent_bytenr && extent_bytenr < dev_bytenr &&
+	      dev_bytenr < fs_bytenr && fs_bytenr < csum_bytenr)) {
+		error("bad tree bytenr order: "
+				"root < extent %llu < %llu, "
+				"extent < dev %llu < %llu, "
+				"dev < fs %llu < %llu, "
+				"fs < csum %llu < %llu",
+				(unsigned long long)root_bytenr,
+				(unsigned long long)extent_bytenr,
+				(unsigned long long)extent_bytenr,
+				(unsigned long long)dev_bytenr,
+				(unsigned long long)dev_bytenr,
+				(unsigned long long)fs_bytenr,
+				(unsigned long long)fs_bytenr,
+				(unsigned long long)csum_bytenr);
+		return -EINVAL;
+	}
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = setup_temp_extent_buffer(buf, cfg, root_bytenr,
+				       BTRFS_ROOT_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	insert_temp_root_item(buf, cfg, &slot, &itemoff,
+			      BTRFS_EXTENT_TREE_OBJECTID, extent_bytenr);
+	insert_temp_root_item(buf, cfg, &slot, &itemoff,
+			      BTRFS_DEV_TREE_OBJECTID, dev_bytenr);
+	insert_temp_root_item(buf, cfg, &slot, &itemoff,
+			      BTRFS_FS_TREE_OBJECTID, fs_bytenr);
+	insert_temp_root_item(buf, cfg, &slot, &itemoff,
+			      BTRFS_CSUM_TREE_OBJECTID, csum_bytenr);
+
+	ret = write_temp_extent_buffer(fd, buf, root_bytenr);
+out:
+	free(buf);
+	return ret;
+}
+
+static int insert_temp_dev_item(int fd, struct extent_buffer *buf,
+				struct btrfs_mkfs_config *cfg,
+				int *slot, u32 *itemoff)
+{
+	struct btrfs_disk_key disk_key;
+	struct btrfs_dev_item *dev_item;
+	char super_buf[BTRFS_SUPER_INFO_SIZE];
+	unsigned char dev_uuid[BTRFS_UUID_SIZE];
+	unsigned char fsid[BTRFS_FSID_SIZE];
+	struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
+	int ret;
+
+	ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE, cfg->super_bytenr);
+	if (ret < BTRFS_SUPER_INFO_SIZE) {
+		ret = (ret < 0 ? -errno : -EIO);
+		goto out;
+	}
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	(*itemoff) -= sizeof(*dev_item);
+	/* setup device item 1, 0 is for replace case */
+	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
+	btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
+	btrfs_set_disk_key_offset(&disk_key, 1);
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_item));
+
+	dev_item = btrfs_item_ptr(buf, *slot, struct btrfs_dev_item);
+	/* Generate device uuid */
+	uuid_generate(dev_uuid);
+	write_extent_buffer(buf, dev_uuid,
+			(unsigned long)btrfs_device_uuid(dev_item),
+			BTRFS_UUID_SIZE);
+	uuid_parse(cfg->fs_uuid, fsid);
+	write_extent_buffer(buf, fsid,
+			(unsigned long)btrfs_device_fsid(dev_item),
+			BTRFS_FSID_SIZE);
+	btrfs_set_device_id(buf, dev_item, 1);
+	btrfs_set_device_generation(buf, dev_item, 0);
+	btrfs_set_device_total_bytes(buf, dev_item, cfg->num_bytes);
+	/*
+	 * The number must match the initial SYSTEM and META chunk size
+	 */
+	btrfs_set_device_bytes_used(buf, dev_item,
+			BTRFS_MKFS_SYSTEM_GROUP_SIZE +
+			BTRFS_CONVERT_META_GROUP_SIZE);
+	btrfs_set_device_io_align(buf, dev_item, cfg->sectorsize);
+	btrfs_set_device_io_width(buf, dev_item, cfg->sectorsize);
+	btrfs_set_device_sector_size(buf, dev_item, cfg->sectorsize);
+	btrfs_set_device_type(buf, dev_item, 0);
+
+	/* Super dev_item is not complete, copy the complete one to sb */
+	read_extent_buffer(buf, &super->dev_item, (unsigned long)dev_item,
+			   sizeof(*dev_item));
+	ret = write_temp_super(fd, super, cfg->super_bytenr);
+	(*slot)++;
+out:
+	return ret;
+}
+
+static int insert_temp_chunk_item(int fd, struct extent_buffer *buf,
+				  struct btrfs_mkfs_config *cfg,
+				  int *slot, u32 *itemoff, u64 start, u64 len,
+				  u64 type)
+{
+	struct btrfs_chunk *chunk;
+	struct btrfs_disk_key disk_key;
+	char super_buf[BTRFS_SUPER_INFO_SIZE];
+	struct btrfs_super_block *sb = (struct btrfs_super_block *)super_buf;
+	int ret = 0;
+
+	ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE,
+		    cfg->super_bytenr);
+	if (ret < BTRFS_SUPER_INFO_SIZE) {
+		ret = (ret < 0 ? ret : -EIO);
+		return ret;
+	}
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	(*itemoff) -= btrfs_chunk_item_size(1);
+	btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
+	btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+	btrfs_set_disk_key_offset(&disk_key, start);
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot),
+			    btrfs_chunk_item_size(1));
+
+	chunk = btrfs_item_ptr(buf, *slot, struct btrfs_chunk);
+	btrfs_set_chunk_length(buf, chunk, len);
+	btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
+	btrfs_set_chunk_stripe_len(buf, chunk, BTRFS_STRIPE_LEN);
+	btrfs_set_chunk_type(buf, chunk, type);
+	btrfs_set_chunk_io_align(buf, chunk, cfg->sectorsize);
+	btrfs_set_chunk_io_width(buf, chunk, cfg->sectorsize);
+	btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
+	btrfs_set_chunk_num_stripes(buf, chunk, 1);
+	/* TODO: Support DUP profile for system chunk */
+	btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
+	/* We are doing 1:1 mapping, so start is its dev offset */
+	btrfs_set_stripe_offset_nr(buf, chunk, 0, start);
+	write_extent_buffer(buf, &sb->dev_item.uuid,
+			    (unsigned long)btrfs_stripe_dev_uuid_nr(chunk, 0),
+			    BTRFS_UUID_SIZE);
+	(*slot)++;
+
+	/*
+	 * If it's system chunk, also copy it to super block.
+	 */
+	if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+		char *cur;
+		u32 array_size;
+
+		cur = (char *)sb->sys_chunk_array
+			+ btrfs_super_sys_array_size(sb);
+		memcpy(cur, &disk_key, sizeof(disk_key));
+		cur += sizeof(disk_key);
+		read_extent_buffer(buf, cur, (unsigned long int)chunk,
+				   btrfs_chunk_item_size(1));
+		array_size = btrfs_super_sys_array_size(sb);
+		array_size += btrfs_chunk_item_size(1) +
+					    sizeof(disk_key);
+		btrfs_set_super_sys_array_size(sb, array_size);
+
+		ret = write_temp_super(fd, sb, cfg->super_bytenr);
+	}
+	return ret;
+}
+
+static int setup_temp_chunk_tree(int fd, struct btrfs_mkfs_config *cfg,
+				 u64 sys_chunk_start, u64 meta_chunk_start,
+				 u64 chunk_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+	int slot = 0;
+	int ret;
+
+	/* Must ensure SYS chunk starts before META chunk */
+	if (meta_chunk_start < sys_chunk_start) {
+		error("wrong chunk order: meta < system %llu < %llu",
+				(unsigned long long)meta_chunk_start,
+				(unsigned long long)sys_chunk_start);
+		return -EINVAL;
+	}
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+	ret = setup_temp_extent_buffer(buf, cfg, chunk_bytenr,
+				       BTRFS_CHUNK_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	ret = insert_temp_dev_item(fd, buf, cfg, &slot, &itemoff);
+	if (ret < 0)
+		goto out;
+	ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
+				     sys_chunk_start,
+				     BTRFS_MKFS_SYSTEM_GROUP_SIZE,
+				     BTRFS_BLOCK_GROUP_SYSTEM);
+	if (ret < 0)
+		goto out;
+	ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
+				     meta_chunk_start,
+				     BTRFS_CONVERT_META_GROUP_SIZE,
+				     BTRFS_BLOCK_GROUP_METADATA);
+	if (ret < 0)
+		goto out;
+	ret = write_temp_extent_buffer(fd, buf, chunk_bytenr);
+
+out:
+	free(buf);
+	return ret;
+}
+
+static void insert_temp_dev_extent(struct extent_buffer *buf,
+				   int *slot, u32 *itemoff, u64 start, u64 len)
+{
+	struct btrfs_dev_extent *dev_extent;
+	struct btrfs_disk_key disk_key;
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	(*itemoff) -= sizeof(*dev_extent);
+	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
+	btrfs_set_disk_key_objectid(&disk_key, 1);
+	btrfs_set_disk_key_offset(&disk_key, start);
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_extent));
+
+	dev_extent = btrfs_item_ptr(buf, *slot, struct btrfs_dev_extent);
+	btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
+					    BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+	btrfs_set_dev_extent_length(buf, dev_extent, len);
+	btrfs_set_dev_extent_chunk_offset(buf, dev_extent, start);
+	btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
+					BTRFS_CHUNK_TREE_OBJECTID);
+	(*slot)++;
+}
+
+static int setup_temp_dev_tree(int fd, struct btrfs_mkfs_config *cfg,
+			       u64 sys_chunk_start, u64 meta_chunk_start,
+			       u64 dev_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+	int slot = 0;
+	int ret;
+
+	/* Must ensure SYS chunk starts before META chunk */
+	if (meta_chunk_start < sys_chunk_start) {
+		error("wrong chunk order: meta < system %llu < %llu",
+				(unsigned long long)meta_chunk_start,
+				(unsigned long long)sys_chunk_start);
+		return -EINVAL;
+	}
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+	ret = setup_temp_extent_buffer(buf, cfg, dev_bytenr,
+				       BTRFS_DEV_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	insert_temp_dev_extent(buf, &slot, &itemoff, sys_chunk_start,
+			       BTRFS_MKFS_SYSTEM_GROUP_SIZE);
+	insert_temp_dev_extent(buf, &slot, &itemoff, meta_chunk_start,
+			       BTRFS_CONVERT_META_GROUP_SIZE);
+	ret = write_temp_extent_buffer(fd, buf, dev_bytenr);
+out:
+	free(buf);
+	return ret;
+}
+
+static int setup_temp_fs_tree(int fd, struct btrfs_mkfs_config *cfg,
+			      u64 fs_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	int ret;
+
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+	ret = setup_temp_extent_buffer(buf, cfg, fs_bytenr,
+				       BTRFS_FS_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	/*
+	 * Temporary fs tree is completely empty.
+	 */
+	ret = write_temp_extent_buffer(fd, buf, fs_bytenr);
+out:
+	free(buf);
+	return ret;
+}
+
+static int setup_temp_csum_tree(int fd, struct btrfs_mkfs_config *cfg,
+				u64 csum_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	int ret;
+
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+	ret = setup_temp_extent_buffer(buf, cfg, csum_bytenr,
+				       BTRFS_CSUM_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	/*
+	 * Temporary csum tree is completely empty.
+	 */
+	ret = write_temp_extent_buffer(fd, buf, csum_bytenr);
+out:
+	free(buf);
+	return ret;
+}
+
+/*
+ * Insert one temporary extent item.
+ *
+ * NOTE: if skinny_metadata is not enabled, this function must be called
+ * after all other trees are initialized.
+ * Or fs without skinny-metadata will be screwed up.
+ */
+static int insert_temp_extent_item(int fd, struct extent_buffer *buf,
+				   struct btrfs_mkfs_config *cfg,
+				   int *slot, u32 *itemoff, u64 bytenr,
+				   u64 ref_root)
+{
+	struct extent_buffer *tmp;
+	struct btrfs_extent_item *ei;
+	struct btrfs_extent_inline_ref *iref;
+	struct btrfs_disk_key disk_key;
+	struct btrfs_disk_key tree_info_key;
+	struct btrfs_tree_block_info *info;
+	int itemsize;
+	int skinny_metadata = cfg->features &
+			      BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA;
+	int ret;
+
+	if (skinny_metadata)
+		itemsize = sizeof(*ei) + sizeof(*iref);
+	else
+		itemsize = sizeof(*ei) + sizeof(*iref) +
+			   sizeof(struct btrfs_tree_block_info);
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	*(itemoff) -= itemsize;
+
+	if (skinny_metadata) {
+		btrfs_set_disk_key_type(&disk_key, BTRFS_METADATA_ITEM_KEY);
+		btrfs_set_disk_key_offset(&disk_key, 0);
+	} else {
+		btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
+		btrfs_set_disk_key_offset(&disk_key, cfg->nodesize);
+	}
+	btrfs_set_disk_key_objectid(&disk_key, bytenr);
+
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot), itemsize);
+
+	ei = btrfs_item_ptr(buf, *slot, struct btrfs_extent_item);
+	btrfs_set_extent_refs(buf, ei, 1);
+	btrfs_set_extent_generation(buf, ei, 1);
+	btrfs_set_extent_flags(buf, ei, BTRFS_EXTENT_FLAG_TREE_BLOCK);
+
+	if (skinny_metadata) {
+		iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+	} else {
+		info = (struct btrfs_tree_block_info *)(ei + 1);
+		iref = (struct btrfs_extent_inline_ref *)(info + 1);
+	}
+	btrfs_set_extent_inline_ref_type(buf, iref,
+					 BTRFS_TREE_BLOCK_REF_KEY);
+	btrfs_set_extent_inline_ref_offset(buf, iref, ref_root);
+
+	(*slot)++;
+	if (skinny_metadata)
+		return 0;
+
+	/*
+	 * Lastly, check the tree block key by read the tree block
+	 * Since we do 1:1 mapping for convert case, we can directly
+	 * read the bytenr from disk
+	 */
+	tmp = malloc(sizeof(*tmp) + cfg->nodesize);
+	if (!tmp)
+		return -ENOMEM;
+	ret = setup_temp_extent_buffer(tmp, cfg, bytenr, ref_root);
+	if (ret < 0)
+		goto out;
+	ret = pread(fd, tmp->data, cfg->nodesize, bytenr);
+	if (ret < cfg->nodesize) {
+		ret = (ret < 0 ? -errno : -EIO);
+		goto out;
+	}
+	if (btrfs_header_nritems(tmp) == 0) {
+		btrfs_set_disk_key_type(&tree_info_key, 0);
+		btrfs_set_disk_key_objectid(&tree_info_key, 0);
+		btrfs_set_disk_key_offset(&tree_info_key, 0);
+	} else {
+		btrfs_item_key(tmp, &tree_info_key, 0);
+	}
+	btrfs_set_tree_block_key(buf, info, &tree_info_key);
+
+out:
+	free(tmp);
+	return ret;
+}
+
+static void insert_temp_block_group(struct extent_buffer *buf,
+				   struct btrfs_mkfs_config *cfg,
+				   int *slot, u32 *itemoff,
+				   u64 bytenr, u64 len, u64 used, u64 flag)
+{
+	struct btrfs_block_group_item bgi;
+	struct btrfs_disk_key disk_key;
+
+	btrfs_set_header_nritems(buf, *slot + 1);
+	(*itemoff) -= sizeof(bgi);
+	btrfs_set_disk_key_type(&disk_key, BTRFS_BLOCK_GROUP_ITEM_KEY);
+	btrfs_set_disk_key_objectid(&disk_key, bytenr);
+	btrfs_set_disk_key_offset(&disk_key, len);
+	btrfs_set_item_key(buf, &disk_key, *slot);
+	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
+	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(bgi));
+
+	btrfs_set_block_group_flags(&bgi, flag);
+	btrfs_set_block_group_used(&bgi, used);
+	btrfs_set_block_group_chunk_objectid(&bgi,
+			BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+	write_extent_buffer(buf, &bgi, btrfs_item_ptr_offset(buf, *slot),
+			    sizeof(bgi));
+	(*slot)++;
+}
+
+static int setup_temp_extent_tree(int fd, struct btrfs_mkfs_config *cfg,
+				  u64 chunk_bytenr, u64 root_bytenr,
+				  u64 extent_bytenr, u64 dev_bytenr,
+				  u64 fs_bytenr, u64 csum_bytenr)
+{
+	struct extent_buffer *buf = NULL;
+	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
+	int slot = 0;
+	int ret;
+
+	/*
+	 * We must ensure provided bytenr are in ascending order,
+	 * or extent tree key order will be broken.
+	 */
+	if (!(chunk_bytenr < root_bytenr && root_bytenr < extent_bytenr &&
+	      extent_bytenr < dev_bytenr && dev_bytenr < fs_bytenr &&
+	      fs_bytenr < csum_bytenr)) {
+		error("bad tree bytenr order: "
+				"chunk < root %llu < %llu, "
+				"root < extent %llu < %llu, "
+				"extent < dev %llu < %llu, "
+				"dev < fs %llu < %llu, "
+				"fs < csum %llu < %llu",
+				(unsigned long long)chunk_bytenr,
+				(unsigned long long)root_bytenr,
+				(unsigned long long)root_bytenr,
+				(unsigned long long)extent_bytenr,
+				(unsigned long long)extent_bytenr,
+				(unsigned long long)dev_bytenr,
+				(unsigned long long)dev_bytenr,
+				(unsigned long long)fs_bytenr,
+				(unsigned long long)fs_bytenr,
+				(unsigned long long)csum_bytenr);
+		return -EINVAL;
+	}
+	buf = malloc(sizeof(*buf) + cfg->nodesize);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = setup_temp_extent_buffer(buf, cfg, extent_bytenr,
+				       BTRFS_EXTENT_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			chunk_bytenr, BTRFS_CHUNK_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	insert_temp_block_group(buf, cfg, &slot, &itemoff, chunk_bytenr,
+			BTRFS_MKFS_SYSTEM_GROUP_SIZE, cfg->nodesize,
+			BTRFS_BLOCK_GROUP_SYSTEM);
+
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			root_bytenr, BTRFS_ROOT_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	/* 5 tree block used, root, extent, dev, fs and csum*/
+	insert_temp_block_group(buf, cfg, &slot, &itemoff, root_bytenr,
+			BTRFS_CONVERT_META_GROUP_SIZE, cfg->nodesize * 5,
+			BTRFS_BLOCK_GROUP_METADATA);
+
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			extent_bytenr, BTRFS_EXTENT_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			dev_bytenr, BTRFS_DEV_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			fs_bytenr, BTRFS_FS_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
+			csum_bytenr, BTRFS_CSUM_TREE_OBJECTID);
+	if (ret < 0)
+		goto out;
+
+	ret = write_temp_extent_buffer(fd, buf, extent_bytenr);
+out:
+	free(buf);
+	return ret;
+}
+
+/*
+ * Improved version of make_btrfs().
+ *
+ * This one will
+ * 1) Do chunk allocation to avoid used data
+ *    And after this function, extent type matches chunk type
+ * 2) Better structured code
+ *    No super long hand written codes to initialized all tree blocks
+ *    Split into small blocks and reuse codes.
+ *    TODO: Reuse tree operation facilities by introducing new flags
+ */
+int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
+			      struct btrfs_convert_context *cctx)
+{
+	struct cache_tree *free = &cctx->free;
+	struct cache_tree *used = &cctx->used;
+	u64 sys_chunk_start;
+	u64 meta_chunk_start;
+	/* chunk tree bytenr, in system chunk */
+	u64 chunk_bytenr;
+	/* metadata trees bytenr, in metadata chunk */
+	u64 root_bytenr;
+	u64 extent_bytenr;
+	u64 dev_bytenr;
+	u64 fs_bytenr;
+	u64 csum_bytenr;
+	int ret;
+
+	/* Shouldn't happen */
+	BUG_ON(cache_tree_empty(used));
+
+	/*
+	 * reserve space for temporary superblock first
+	 * Here we allocate a little larger space, to keep later
+	 * free space will be STRIPE_LEN aligned
+	 */
+	ret = reserve_free_space(free, BTRFS_STRIPE_LEN,
+				 &cfg->super_bytenr);
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * Then reserve system chunk space
+	 * TODO: Change system group size depending on cctx->total_bytes.
+	 * If using current 4M, it can only handle less than one TB for
+	 * worst case and then run out of sys space.
+	 */
+	ret = reserve_free_space(free, BTRFS_MKFS_SYSTEM_GROUP_SIZE,
+				 &sys_chunk_start);
+	if (ret < 0)
+		goto out;
+	ret = reserve_free_space(free, BTRFS_CONVERT_META_GROUP_SIZE,
+				 &meta_chunk_start);
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * Allocated meta/sys chunks will be mapped 1:1 with device offset.
+	 *
+	 * Inside the allocated metadata chunk, the layout will be:
+	 *  | offset		| contents	|
+	 *  -------------------------------------
+	 *  | +0		| tree root	|
+	 *  | +nodesize		| extent root	|
+	 *  | +nodesize * 2	| device root	|
+	 *  | +nodesize * 3	| fs tree	|
+	 *  | +nodesize * 4	| csum tree	|
+	 *  -------------------------------------
+	 * Inside the allocated system chunk, the layout will be:
+	 *  | offset		| contents	|
+	 *  -------------------------------------
+	 *  | +0		| chunk root	|
+	 *  -------------------------------------
+	 */
+	chunk_bytenr = sys_chunk_start;
+	root_bytenr = meta_chunk_start;
+	extent_bytenr = meta_chunk_start + cfg->nodesize;
+	dev_bytenr = meta_chunk_start + cfg->nodesize * 2;
+	fs_bytenr = meta_chunk_start + cfg->nodesize * 3;
+	csum_bytenr = meta_chunk_start + cfg->nodesize * 4;
+
+	ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr);
+	if (ret < 0)
+		goto out;
+
+	ret = setup_temp_root_tree(fd, cfg, root_bytenr, extent_bytenr,
+				   dev_bytenr, fs_bytenr, csum_bytenr);
+	if (ret < 0)
+		goto out;
+	ret = setup_temp_chunk_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
+				    chunk_bytenr);
+	if (ret < 0)
+		goto out;
+	ret = setup_temp_dev_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
+				  dev_bytenr);
+	if (ret < 0)
+		goto out;
+	ret = setup_temp_fs_tree(fd, cfg, fs_bytenr);
+	if (ret < 0)
+		goto out;
+	ret = setup_temp_csum_tree(fd, cfg, csum_bytenr);
+	if (ret < 0)
+		goto out;
+	/*
+	 * Setup extent tree last, since it may need to read tree block key
+	 * for non-skinny metadata case.
+	 */
+	ret = setup_temp_extent_tree(fd, cfg, chunk_bytenr, root_bytenr,
+				     extent_bytenr, dev_bytenr, fs_bytenr,
+				     csum_bytenr);
+out:
+	return ret;
+}
+
diff --git a/convert/common.h b/convert/common.h
index 236e9a80..55a65547 100644
--- a/convert/common.h
+++ b/convert/common.h
@@ -24,6 +24,7 @@
 
 #include "kerncompat.h"
 #include "common-defs.h"
+#include "extent-cache.h"
 
 struct btrfs_mkfs_config;
 
diff --git a/utils.c b/utils.c
index a4bc213e..d24993e8 100644
--- a/utils.c
+++ b/utils.c
@@ -50,8 +50,6 @@
 #include "volumes.h"
 #include "ioctl.h"
 #include "commands.h"
-#include "mkfs/common.h"
-#include "convert/common.h"
 
 #ifndef BLKDISCARD
 #define BLKDISCARD	_IO(0x12,119)
@@ -125,869 +123,11 @@ int test_uuid_unique(char *fs_uuid)
 	return unique;
 }
 
-/*
- * Reserve space from free_tree.
- * The algorithm is very simple, find the first cache_extent with enough space
- * and allocate from its beginning.
- */
-static int reserve_free_space(struct cache_tree *free_tree, u64 len,
-			      u64 *ret_start)
-{
-	struct cache_extent *cache;
-	int found = 0;
-
-	ASSERT(ret_start != NULL);
-	cache = first_cache_extent(free_tree);
-	while (cache) {
-		if (cache->size > len) {
-			found = 1;
-			*ret_start = cache->start;
-
-			cache->size -= len;
-			if (cache->size == 0) {
-				remove_cache_extent(free_tree, cache);
-				free(cache);
-			} else {
-				cache->start += len;
-			}
-			break;
-		}
-		cache = next_cache_extent(cache);
-	}
-	if (!found)
-		return -ENOSPC;
-	return 0;
-}
-
-static inline int write_temp_super(int fd, struct btrfs_super_block *sb,
-				   u64 sb_bytenr)
-{
-	u32 crc = ~(u32)0;
-	int ret;
-
-	crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
-			      BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
-	btrfs_csum_final(crc, &sb->csum[0]);
-	ret = pwrite(fd, sb, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
-	if (ret < BTRFS_SUPER_INFO_SIZE)
-		ret = (ret < 0 ? -errno : -EIO);
-	else
-		ret = 0;
-	return ret;
-}
-
-/*
- * Setup temporary superblock at cfg->super_bynter
- * Needed info are extracted from cfg, and root_bytenr, chunk_bytenr
- *
- * For now sys chunk array will be empty and dev_item is empty too.
- * They will be re-initialized at temp chunk tree setup.
- *
- * The superblock signature is not valid, denotes a partially created
- * filesystem, needs to be finalized.
- */
-static int setup_temp_super(int fd, struct btrfs_mkfs_config *cfg,
-			    u64 root_bytenr, u64 chunk_bytenr)
-{
-	unsigned char chunk_uuid[BTRFS_UUID_SIZE];
-	char super_buf[BTRFS_SUPER_INFO_SIZE];
-	struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
-	int ret;
-
-	memset(super_buf, 0, BTRFS_SUPER_INFO_SIZE);
-	cfg->num_bytes = round_down(cfg->num_bytes, cfg->sectorsize);
-
-	if (*cfg->fs_uuid) {
-		if (uuid_parse(cfg->fs_uuid, super->fsid) != 0) {
-			error("cound not parse UUID: %s", cfg->fs_uuid);
-			ret = -EINVAL;
-			goto out;
-		}
-		if (!test_uuid_unique(cfg->fs_uuid)) {
-			error("non-unique UUID: %s", cfg->fs_uuid);
-			ret = -EINVAL;
-			goto out;
-		}
-	} else {
-		uuid_generate(super->fsid);
-		uuid_unparse(super->fsid, cfg->fs_uuid);
-	}
-	uuid_generate(chunk_uuid);
-	uuid_unparse(chunk_uuid, cfg->chunk_uuid);
-
-	btrfs_set_super_bytenr(super, cfg->super_bytenr);
-	btrfs_set_super_num_devices(super, 1);
-	btrfs_set_super_magic(super, BTRFS_MAGIC_PARTIAL);
-	btrfs_set_super_generation(super, 1);
-	btrfs_set_super_root(super, root_bytenr);
-	btrfs_set_super_chunk_root(super, chunk_bytenr);
-	btrfs_set_super_total_bytes(super, cfg->num_bytes);
-	/*
-	 * Temporary filesystem will only have 6 tree roots:
-	 * chunk tree, root tree, extent_tree, device tree, fs tree
-	 * and csum tree.
-	 */
-	btrfs_set_super_bytes_used(super, 6 * cfg->nodesize);
-	btrfs_set_super_sectorsize(super, cfg->sectorsize);
-	btrfs_set_super_leafsize(super, cfg->nodesize);
-	btrfs_set_super_nodesize(super, cfg->nodesize);
-	btrfs_set_super_stripesize(super, cfg->stripesize);
-	btrfs_set_super_csum_type(super, BTRFS_CSUM_TYPE_CRC32);
-	btrfs_set_super_chunk_root(super, chunk_bytenr);
-	btrfs_set_super_cache_generation(super, -1);
-	btrfs_set_super_incompat_flags(super, cfg->features);
-	if (cfg->label)
-		__strncpy_null(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
-
-	/* Sys chunk array will be re-initialized at chunk tree init time */
-	super->sys_chunk_array_size = 0;
-
-	ret = write_temp_super(fd, super, cfg->super_bytenr);
-out:
-	return ret;
-}
-
-/*
- * Setup an extent buffer for tree block.
- */
-static int setup_temp_extent_buffer(struct extent_buffer *buf,
-				    struct btrfs_mkfs_config *cfg,
-				    u64 bytenr, u64 owner)
-{
-	unsigned char fsid[BTRFS_FSID_SIZE];
-	unsigned char chunk_uuid[BTRFS_UUID_SIZE];
-	int ret;
-
-	ret = uuid_parse(cfg->fs_uuid, fsid);
-	if (ret)
-		return -EINVAL;
-	ret = uuid_parse(cfg->chunk_uuid, chunk_uuid);
-	if (ret)
-		return -EINVAL;
-
-	memset(buf->data, 0, cfg->nodesize);
-	buf->len = cfg->nodesize;
-	btrfs_set_header_bytenr(buf, bytenr);
-	btrfs_set_header_generation(buf, 1);
-	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
-	btrfs_set_header_owner(buf, owner);
-	btrfs_set_header_flags(buf, BTRFS_HEADER_FLAG_WRITTEN);
-	write_extent_buffer(buf, chunk_uuid, btrfs_header_chunk_tree_uuid(buf),
-			    BTRFS_UUID_SIZE);
-	write_extent_buffer(buf, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
-	return 0;
-}
-
-static inline int write_temp_extent_buffer(int fd, struct extent_buffer *buf,
-					   u64 bytenr)
-{
-	int ret;
-
-	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
-
-	/* Temporary extent buffer is always mapped 1:1 on disk */
-	ret = pwrite(fd, buf->data, buf->len, bytenr);
-	if (ret < buf->len)
-		ret = (ret < 0 ? ret : -EIO);
-	else
-		ret = 0;
-	return ret;
-}
-
 /*
  * Insert a root item for temporary tree root
  *
  * Only used in make_btrfs_v2().
  */
-static void insert_temp_root_item(struct extent_buffer *buf,
-				  struct btrfs_mkfs_config *cfg,
-				  int *slot, u32 *itemoff, u64 objectid,
-				  u64 bytenr)
-{
-	struct btrfs_root_item root_item;
-	struct btrfs_inode_item *inode_item;
-	struct btrfs_disk_key disk_key;
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	(*itemoff) -= sizeof(root_item);
-	memset(&root_item, 0, sizeof(root_item));
-	inode_item = &root_item.inode;
-	btrfs_set_stack_inode_generation(inode_item, 1);
-	btrfs_set_stack_inode_size(inode_item, 3);
-	btrfs_set_stack_inode_nlink(inode_item, 1);
-	btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
-	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
-	btrfs_set_root_refs(&root_item, 1);
-	btrfs_set_root_used(&root_item, cfg->nodesize);
-	btrfs_set_root_generation(&root_item, 1);
-	btrfs_set_root_bytenr(&root_item, bytenr);
-
-	memset(&disk_key, 0, sizeof(disk_key));
-	btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
-	btrfs_set_disk_key_objectid(&disk_key, objectid);
-	btrfs_set_disk_key_offset(&disk_key, 0);
-
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(root_item));
-	write_extent_buffer(buf, &root_item,
-			    btrfs_item_ptr_offset(buf, *slot),
-			    sizeof(root_item));
-	(*slot)++;
-}
-
-static int setup_temp_root_tree(int fd, struct btrfs_mkfs_config *cfg,
-				u64 root_bytenr, u64 extent_bytenr,
-				u64 dev_bytenr, u64 fs_bytenr, u64 csum_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
-	int slot = 0;
-	int ret;
-
-	/*
-	 * Provided bytenr must in ascending order, or tree root will have a
-	 * bad key order.
-	 */
-	if (!(root_bytenr < extent_bytenr && extent_bytenr < dev_bytenr &&
-	      dev_bytenr < fs_bytenr && fs_bytenr < csum_bytenr)) {
-		error("bad tree bytenr order: "
-				"root < extent %llu < %llu, "
-				"extent < dev %llu < %llu, "
-				"dev < fs %llu < %llu, "
-				"fs < csum %llu < %llu",
-				(unsigned long long)root_bytenr,
-				(unsigned long long)extent_bytenr,
-				(unsigned long long)extent_bytenr,
-				(unsigned long long)dev_bytenr,
-				(unsigned long long)dev_bytenr,
-				(unsigned long long)fs_bytenr,
-				(unsigned long long)fs_bytenr,
-				(unsigned long long)csum_bytenr);
-		return -EINVAL;
-	}
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-
-	ret = setup_temp_extent_buffer(buf, cfg, root_bytenr,
-				       BTRFS_ROOT_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	insert_temp_root_item(buf, cfg, &slot, &itemoff,
-			      BTRFS_EXTENT_TREE_OBJECTID, extent_bytenr);
-	insert_temp_root_item(buf, cfg, &slot, &itemoff,
-			      BTRFS_DEV_TREE_OBJECTID, dev_bytenr);
-	insert_temp_root_item(buf, cfg, &slot, &itemoff,
-			      BTRFS_FS_TREE_OBJECTID, fs_bytenr);
-	insert_temp_root_item(buf, cfg, &slot, &itemoff,
-			      BTRFS_CSUM_TREE_OBJECTID, csum_bytenr);
-
-	ret = write_temp_extent_buffer(fd, buf, root_bytenr);
-out:
-	free(buf);
-	return ret;
-}
-
-static int insert_temp_dev_item(int fd, struct extent_buffer *buf,
-				struct btrfs_mkfs_config *cfg,
-				int *slot, u32 *itemoff)
-{
-	struct btrfs_disk_key disk_key;
-	struct btrfs_dev_item *dev_item;
-	char super_buf[BTRFS_SUPER_INFO_SIZE];
-	unsigned char dev_uuid[BTRFS_UUID_SIZE];
-	unsigned char fsid[BTRFS_FSID_SIZE];
-	struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
-	int ret;
-
-	ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE, cfg->super_bytenr);
-	if (ret < BTRFS_SUPER_INFO_SIZE) {
-		ret = (ret < 0 ? -errno : -EIO);
-		goto out;
-	}
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	(*itemoff) -= sizeof(*dev_item);
-	/* setup device item 1, 0 is for replace case */
-	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
-	btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
-	btrfs_set_disk_key_offset(&disk_key, 1);
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_item));
-
-	dev_item = btrfs_item_ptr(buf, *slot, struct btrfs_dev_item);
-	/* Generate device uuid */
-	uuid_generate(dev_uuid);
-	write_extent_buffer(buf, dev_uuid,
-			(unsigned long)btrfs_device_uuid(dev_item),
-			BTRFS_UUID_SIZE);
-	uuid_parse(cfg->fs_uuid, fsid);
-	write_extent_buffer(buf, fsid,
-			(unsigned long)btrfs_device_fsid(dev_item),
-			BTRFS_FSID_SIZE);
-	btrfs_set_device_id(buf, dev_item, 1);
-	btrfs_set_device_generation(buf, dev_item, 0);
-	btrfs_set_device_total_bytes(buf, dev_item, cfg->num_bytes);
-	/*
-	 * The number must match the initial SYSTEM and META chunk size
-	 */
-	btrfs_set_device_bytes_used(buf, dev_item,
-			BTRFS_MKFS_SYSTEM_GROUP_SIZE +
-			BTRFS_CONVERT_META_GROUP_SIZE);
-	btrfs_set_device_io_align(buf, dev_item, cfg->sectorsize);
-	btrfs_set_device_io_width(buf, dev_item, cfg->sectorsize);
-	btrfs_set_device_sector_size(buf, dev_item, cfg->sectorsize);
-	btrfs_set_device_type(buf, dev_item, 0);
-
-	/* Super dev_item is not complete, copy the complete one to sb */
-	read_extent_buffer(buf, &super->dev_item, (unsigned long)dev_item,
-			   sizeof(*dev_item));
-	ret = write_temp_super(fd, super, cfg->super_bytenr);
-	(*slot)++;
-out:
-	return ret;
-}
-
-static int insert_temp_chunk_item(int fd, struct extent_buffer *buf,
-				  struct btrfs_mkfs_config *cfg,
-				  int *slot, u32 *itemoff, u64 start, u64 len,
-				  u64 type)
-{
-	struct btrfs_chunk *chunk;
-	struct btrfs_disk_key disk_key;
-	char super_buf[BTRFS_SUPER_INFO_SIZE];
-	struct btrfs_super_block *sb = (struct btrfs_super_block *)super_buf;
-	int ret = 0;
-
-	ret = pread(fd, super_buf, BTRFS_SUPER_INFO_SIZE,
-		    cfg->super_bytenr);
-	if (ret < BTRFS_SUPER_INFO_SIZE) {
-		ret = (ret < 0 ? ret : -EIO);
-		return ret;
-	}
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	(*itemoff) -= btrfs_chunk_item_size(1);
-	btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
-	btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
-	btrfs_set_disk_key_offset(&disk_key, start);
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot),
-			    btrfs_chunk_item_size(1));
-
-	chunk = btrfs_item_ptr(buf, *slot, struct btrfs_chunk);
-	btrfs_set_chunk_length(buf, chunk, len);
-	btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
-	btrfs_set_chunk_stripe_len(buf, chunk, BTRFS_STRIPE_LEN);
-	btrfs_set_chunk_type(buf, chunk, type);
-	btrfs_set_chunk_io_align(buf, chunk, cfg->sectorsize);
-	btrfs_set_chunk_io_width(buf, chunk, cfg->sectorsize);
-	btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
-	btrfs_set_chunk_num_stripes(buf, chunk, 1);
-	/* TODO: Support DUP profile for system chunk */
-	btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
-	/* We are doing 1:1 mapping, so start is its dev offset */
-	btrfs_set_stripe_offset_nr(buf, chunk, 0, start);
-	write_extent_buffer(buf, &sb->dev_item.uuid,
-			    (unsigned long)btrfs_stripe_dev_uuid_nr(chunk, 0),
-			    BTRFS_UUID_SIZE);
-	(*slot)++;
-
-	/*
-	 * If it's system chunk, also copy it to super block.
-	 */
-	if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
-		char *cur;
-		u32 array_size;
-
-		cur = (char *)sb->sys_chunk_array
-			+ btrfs_super_sys_array_size(sb);
-		memcpy(cur, &disk_key, sizeof(disk_key));
-		cur += sizeof(disk_key);
-		read_extent_buffer(buf, cur, (unsigned long int)chunk,
-				   btrfs_chunk_item_size(1));
-		array_size = btrfs_super_sys_array_size(sb);
-		array_size += btrfs_chunk_item_size(1) +
-					    sizeof(disk_key);
-		btrfs_set_super_sys_array_size(sb, array_size);
-
-		ret = write_temp_super(fd, sb, cfg->super_bytenr);
-	}
-	return ret;
-}
-
-static int setup_temp_chunk_tree(int fd, struct btrfs_mkfs_config *cfg,
-				 u64 sys_chunk_start, u64 meta_chunk_start,
-				 u64 chunk_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
-	int slot = 0;
-	int ret;
-
-	/* Must ensure SYS chunk starts before META chunk */
-	if (meta_chunk_start < sys_chunk_start) {
-		error("wrong chunk order: meta < system %llu < %llu",
-				(unsigned long long)meta_chunk_start,
-				(unsigned long long)sys_chunk_start);
-		return -EINVAL;
-	}
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-	ret = setup_temp_extent_buffer(buf, cfg, chunk_bytenr,
-				       BTRFS_CHUNK_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	ret = insert_temp_dev_item(fd, buf, cfg, &slot, &itemoff);
-	if (ret < 0)
-		goto out;
-	ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
-				     sys_chunk_start,
-				     BTRFS_MKFS_SYSTEM_GROUP_SIZE,
-				     BTRFS_BLOCK_GROUP_SYSTEM);
-	if (ret < 0)
-		goto out;
-	ret = insert_temp_chunk_item(fd, buf, cfg, &slot, &itemoff,
-				     meta_chunk_start,
-				     BTRFS_CONVERT_META_GROUP_SIZE,
-				     BTRFS_BLOCK_GROUP_METADATA);
-	if (ret < 0)
-		goto out;
-	ret = write_temp_extent_buffer(fd, buf, chunk_bytenr);
-
-out:
-	free(buf);
-	return ret;
-}
-
-static void insert_temp_dev_extent(struct extent_buffer *buf,
-				   int *slot, u32 *itemoff, u64 start, u64 len)
-{
-	struct btrfs_dev_extent *dev_extent;
-	struct btrfs_disk_key disk_key;
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	(*itemoff) -= sizeof(*dev_extent);
-	btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
-	btrfs_set_disk_key_objectid(&disk_key, 1);
-	btrfs_set_disk_key_offset(&disk_key, start);
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(*dev_extent));
-
-	dev_extent = btrfs_item_ptr(buf, *slot, struct btrfs_dev_extent);
-	btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
-					    BTRFS_FIRST_CHUNK_TREE_OBJECTID);
-	btrfs_set_dev_extent_length(buf, dev_extent, len);
-	btrfs_set_dev_extent_chunk_offset(buf, dev_extent, start);
-	btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
-					BTRFS_CHUNK_TREE_OBJECTID);
-	(*slot)++;
-}
-
-static int setup_temp_dev_tree(int fd, struct btrfs_mkfs_config *cfg,
-			       u64 sys_chunk_start, u64 meta_chunk_start,
-			       u64 dev_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
-	int slot = 0;
-	int ret;
-
-	/* Must ensure SYS chunk starts before META chunk */
-	if (meta_chunk_start < sys_chunk_start) {
-		error("wrong chunk order: meta < system %llu < %llu",
-				(unsigned long long)meta_chunk_start,
-				(unsigned long long)sys_chunk_start);
-		return -EINVAL;
-	}
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-	ret = setup_temp_extent_buffer(buf, cfg, dev_bytenr,
-				       BTRFS_DEV_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	insert_temp_dev_extent(buf, &slot, &itemoff, sys_chunk_start,
-			       BTRFS_MKFS_SYSTEM_GROUP_SIZE);
-	insert_temp_dev_extent(buf, &slot, &itemoff, meta_chunk_start,
-			       BTRFS_CONVERT_META_GROUP_SIZE);
-	ret = write_temp_extent_buffer(fd, buf, dev_bytenr);
-out:
-	free(buf);
-	return ret;
-}
-
-static int setup_temp_fs_tree(int fd, struct btrfs_mkfs_config *cfg,
-			      u64 fs_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	int ret;
-
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-	ret = setup_temp_extent_buffer(buf, cfg, fs_bytenr,
-				       BTRFS_FS_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	/*
-	 * Temporary fs tree is completely empty.
-	 */
-	ret = write_temp_extent_buffer(fd, buf, fs_bytenr);
-out:
-	free(buf);
-	return ret;
-}
-
-static int setup_temp_csum_tree(int fd, struct btrfs_mkfs_config *cfg,
-				u64 csum_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	int ret;
-
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-	ret = setup_temp_extent_buffer(buf, cfg, csum_bytenr,
-				       BTRFS_CSUM_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	/*
-	 * Temporary csum tree is completely empty.
-	 */
-	ret = write_temp_extent_buffer(fd, buf, csum_bytenr);
-out:
-	free(buf);
-	return ret;
-}
-
-/*
- * Insert one temporary extent item.
- *
- * NOTE: if skinny_metadata is not enabled, this function must be called
- * after all other trees are initialized.
- * Or fs without skinny-metadata will be screwed up.
- */
-static int insert_temp_extent_item(int fd, struct extent_buffer *buf,
-				   struct btrfs_mkfs_config *cfg,
-				   int *slot, u32 *itemoff, u64 bytenr,
-				   u64 ref_root)
-{
-	struct extent_buffer *tmp;
-	struct btrfs_extent_item *ei;
-	struct btrfs_extent_inline_ref *iref;
-	struct btrfs_disk_key disk_key;
-	struct btrfs_disk_key tree_info_key;
-	struct btrfs_tree_block_info *info;
-	int itemsize;
-	int skinny_metadata = cfg->features &
-			      BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA;
-	int ret;
-
-	if (skinny_metadata)
-		itemsize = sizeof(*ei) + sizeof(*iref);
-	else
-		itemsize = sizeof(*ei) + sizeof(*iref) +
-			   sizeof(struct btrfs_tree_block_info);
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	*(itemoff) -= itemsize;
-
-	if (skinny_metadata) {
-		btrfs_set_disk_key_type(&disk_key, BTRFS_METADATA_ITEM_KEY);
-		btrfs_set_disk_key_offset(&disk_key, 0);
-	} else {
-		btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
-		btrfs_set_disk_key_offset(&disk_key, cfg->nodesize);
-	}
-	btrfs_set_disk_key_objectid(&disk_key, bytenr);
-
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot), itemsize);
-
-	ei = btrfs_item_ptr(buf, *slot, struct btrfs_extent_item);
-	btrfs_set_extent_refs(buf, ei, 1);
-	btrfs_set_extent_generation(buf, ei, 1);
-	btrfs_set_extent_flags(buf, ei, BTRFS_EXTENT_FLAG_TREE_BLOCK);
-
-	if (skinny_metadata) {
-		iref = (struct btrfs_extent_inline_ref *)(ei + 1);
-	} else {
-		info = (struct btrfs_tree_block_info *)(ei + 1);
-		iref = (struct btrfs_extent_inline_ref *)(info + 1);
-	}
-	btrfs_set_extent_inline_ref_type(buf, iref,
-					 BTRFS_TREE_BLOCK_REF_KEY);
-	btrfs_set_extent_inline_ref_offset(buf, iref, ref_root);
-
-	(*slot)++;
-	if (skinny_metadata)
-		return 0;
-
-	/*
-	 * Lastly, check the tree block key by read the tree block
-	 * Since we do 1:1 mapping for convert case, we can directly
-	 * read the bytenr from disk
-	 */
-	tmp = malloc(sizeof(*tmp) + cfg->nodesize);
-	if (!tmp)
-		return -ENOMEM;
-	ret = setup_temp_extent_buffer(tmp, cfg, bytenr, ref_root);
-	if (ret < 0)
-		goto out;
-	ret = pread(fd, tmp->data, cfg->nodesize, bytenr);
-	if (ret < cfg->nodesize) {
-		ret = (ret < 0 ? -errno : -EIO);
-		goto out;
-	}
-	if (btrfs_header_nritems(tmp) == 0) {
-		btrfs_set_disk_key_type(&tree_info_key, 0);
-		btrfs_set_disk_key_objectid(&tree_info_key, 0);
-		btrfs_set_disk_key_offset(&tree_info_key, 0);
-	} else {
-		btrfs_item_key(tmp, &tree_info_key, 0);
-	}
-	btrfs_set_tree_block_key(buf, info, &tree_info_key);
-
-out:
-	free(tmp);
-	return ret;
-}
-
-static void insert_temp_block_group(struct extent_buffer *buf,
-				   struct btrfs_mkfs_config *cfg,
-				   int *slot, u32 *itemoff,
-				   u64 bytenr, u64 len, u64 used, u64 flag)
-{
-	struct btrfs_block_group_item bgi;
-	struct btrfs_disk_key disk_key;
-
-	btrfs_set_header_nritems(buf, *slot + 1);
-	(*itemoff) -= sizeof(bgi);
-	btrfs_set_disk_key_type(&disk_key, BTRFS_BLOCK_GROUP_ITEM_KEY);
-	btrfs_set_disk_key_objectid(&disk_key, bytenr);
-	btrfs_set_disk_key_offset(&disk_key, len);
-	btrfs_set_item_key(buf, &disk_key, *slot);
-	btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff);
-	btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(bgi));
-
-	btrfs_set_block_group_flags(&bgi, flag);
-	btrfs_set_block_group_used(&bgi, used);
-	btrfs_set_block_group_chunk_objectid(&bgi,
-			BTRFS_FIRST_CHUNK_TREE_OBJECTID);
-	write_extent_buffer(buf, &bgi, btrfs_item_ptr_offset(buf, *slot),
-			    sizeof(bgi));
-	(*slot)++;
-}
-
-static int setup_temp_extent_tree(int fd, struct btrfs_mkfs_config *cfg,
-				  u64 chunk_bytenr, u64 root_bytenr,
-				  u64 extent_bytenr, u64 dev_bytenr,
-				  u64 fs_bytenr, u64 csum_bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
-	int slot = 0;
-	int ret;
-
-	/*
-	 * We must ensure provided bytenr are in ascending order,
-	 * or extent tree key order will be broken.
-	 */
-	if (!(chunk_bytenr < root_bytenr && root_bytenr < extent_bytenr &&
-	      extent_bytenr < dev_bytenr && dev_bytenr < fs_bytenr &&
-	      fs_bytenr < csum_bytenr)) {
-		error("bad tree bytenr order: "
-				"chunk < root %llu < %llu, "
-				"root < extent %llu < %llu, "
-				"extent < dev %llu < %llu, "
-				"dev < fs %llu < %llu, "
-				"fs < csum %llu < %llu",
-				(unsigned long long)chunk_bytenr,
-				(unsigned long long)root_bytenr,
-				(unsigned long long)root_bytenr,
-				(unsigned long long)extent_bytenr,
-				(unsigned long long)extent_bytenr,
-				(unsigned long long)dev_bytenr,
-				(unsigned long long)dev_bytenr,
-				(unsigned long long)fs_bytenr,
-				(unsigned long long)fs_bytenr,
-				(unsigned long long)csum_bytenr);
-		return -EINVAL;
-	}
-	buf = malloc(sizeof(*buf) + cfg->nodesize);
-	if (!buf)
-		return -ENOMEM;
-
-	ret = setup_temp_extent_buffer(buf, cfg, extent_bytenr,
-				       BTRFS_EXTENT_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			chunk_bytenr, BTRFS_CHUNK_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	insert_temp_block_group(buf, cfg, &slot, &itemoff, chunk_bytenr,
-			BTRFS_MKFS_SYSTEM_GROUP_SIZE, cfg->nodesize,
-			BTRFS_BLOCK_GROUP_SYSTEM);
-
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			root_bytenr, BTRFS_ROOT_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	/* 5 tree block used, root, extent, dev, fs and csum*/
-	insert_temp_block_group(buf, cfg, &slot, &itemoff, root_bytenr,
-			BTRFS_CONVERT_META_GROUP_SIZE, cfg->nodesize * 5,
-			BTRFS_BLOCK_GROUP_METADATA);
-
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			extent_bytenr, BTRFS_EXTENT_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			dev_bytenr, BTRFS_DEV_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			fs_bytenr, BTRFS_FS_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-	ret = insert_temp_extent_item(fd, buf, cfg, &slot, &itemoff,
-			csum_bytenr, BTRFS_CSUM_TREE_OBJECTID);
-	if (ret < 0)
-		goto out;
-
-	ret = write_temp_extent_buffer(fd, buf, extent_bytenr);
-out:
-	free(buf);
-	return ret;
-}
-
-/*
- * Improved version of make_btrfs().
- *
- * This one will
- * 1) Do chunk allocation to avoid used data
- *    And after this function, extent type matches chunk type
- * 2) Better structured code
- *    No super long hand written codes to initialized all tree blocks
- *    Split into small blocks and reuse codes.
- *    TODO: Reuse tree operation facilities by introducing new flags
- */
-int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
-			      struct btrfs_convert_context *cctx)
-{
-	struct cache_tree *free = &cctx->free;
-	struct cache_tree *used = &cctx->used;
-	u64 sys_chunk_start;
-	u64 meta_chunk_start;
-	/* chunk tree bytenr, in system chunk */
-	u64 chunk_bytenr;
-	/* metadata trees bytenr, in metadata chunk */
-	u64 root_bytenr;
-	u64 extent_bytenr;
-	u64 dev_bytenr;
-	u64 fs_bytenr;
-	u64 csum_bytenr;
-	int ret;
-
-	/* Shouldn't happen */
-	BUG_ON(cache_tree_empty(used));
-
-	/*
-	 * reserve space for temporary superblock first
-	 * Here we allocate a little larger space, to keep later
-	 * free space will be STRIPE_LEN aligned
-	 */
-	ret = reserve_free_space(free, BTRFS_STRIPE_LEN,
-				 &cfg->super_bytenr);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * Then reserve system chunk space
-	 * TODO: Change system group size depending on cctx->total_bytes.
-	 * If using current 4M, it can only handle less than one TB for
-	 * worst case and then run out of sys space.
-	 */
-	ret = reserve_free_space(free, BTRFS_MKFS_SYSTEM_GROUP_SIZE,
-				 &sys_chunk_start);
-	if (ret < 0)
-		goto out;
-	ret = reserve_free_space(free, BTRFS_CONVERT_META_GROUP_SIZE,
-				 &meta_chunk_start);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * Allocated meta/sys chunks will be mapped 1:1 with device offset.
-	 *
-	 * Inside the allocated metadata chunk, the layout will be:
-	 *  | offset		| contents	|
-	 *  -------------------------------------
-	 *  | +0		| tree root	|
-	 *  | +nodesize		| extent root	|
-	 *  | +nodesize * 2	| device root	|
-	 *  | +nodesize * 3	| fs tree	|
-	 *  | +nodesize * 4	| csum tree	|
-	 *  -------------------------------------
-	 * Inside the allocated system chunk, the layout will be:
-	 *  | offset		| contents	|
-	 *  -------------------------------------
-	 *  | +0		| chunk root	|
-	 *  -------------------------------------
-	 */
-	chunk_bytenr = sys_chunk_start;
-	root_bytenr = meta_chunk_start;
-	extent_bytenr = meta_chunk_start + cfg->nodesize;
-	dev_bytenr = meta_chunk_start + cfg->nodesize * 2;
-	fs_bytenr = meta_chunk_start + cfg->nodesize * 3;
-	csum_bytenr = meta_chunk_start + cfg->nodesize * 4;
-
-	ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr);
-	if (ret < 0)
-		goto out;
-
-	ret = setup_temp_root_tree(fd, cfg, root_bytenr, extent_bytenr,
-				   dev_bytenr, fs_bytenr, csum_bytenr);
-	if (ret < 0)
-		goto out;
-	ret = setup_temp_chunk_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
-				    chunk_bytenr);
-	if (ret < 0)
-		goto out;
-	ret = setup_temp_dev_tree(fd, cfg, sys_chunk_start, meta_chunk_start,
-				  dev_bytenr);
-	if (ret < 0)
-		goto out;
-	ret = setup_temp_fs_tree(fd, cfg, fs_bytenr);
-	if (ret < 0)
-		goto out;
-	ret = setup_temp_csum_tree(fd, cfg, csum_bytenr);
-	if (ret < 0)
-		goto out;
-	/*
-	 * Setup extent tree last, since it may need to read tree block key
-	 * for non-skinny metadata case.
-	 */
-	ret = setup_temp_extent_tree(fd, cfg, chunk_bytenr, root_bytenr,
-				     extent_bytenr, dev_bytenr, fs_bytenr,
-				     csum_bytenr);
-out:
-	return ret;
-}
-
 #define VERSION_TO_STRING3(a,b,c)	#a "." #b "." #c, KERNEL_VERSION(a,b,c)
 #define VERSION_TO_STRING2(a,b)		#a "." #b, KERNEL_VERSION(a,b,0)