btrfs-progs: standardize tool source filenames

For any btrfs-$FOO executable, rename the main source file from
$FOO.c to to btrfs-$FOO.c

This makes it slightly more obvious what's building what,
and allows us to write a default rule in the Makefile for
these tools.

(also add btrfs-calc-size to the list of objects to remove
on make clean)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

1 files changed, 2824 insertions, 0 deletions

diff --git a/btrfs-convert.c b/btrfs-convert.c
new file mode 100644
index 00000000..399856f9
--- /dev/null
+++ b/btrfs-convert.c
@@ -0,0 +1,2824 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * 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.
+ */
+
+#define _XOPEN_SOURCE 600
+#define _GNU_SOURCE 1
+
+#include "kerncompat.h"
+
+#ifndef __CHECKER__
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/acl.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <uuid/uuid.h>
+#include <linux/fs.h>
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "volumes.h"
+#include "transaction.h"
+#include "crc32c.h"
+#include "utils.h"
+#include <ext2fs/ext2_fs.h>
+#include <ext2fs/ext2fs.h>
+#include <ext2fs/ext2_ext_attr.h>
+
+#define INO_OFFSET (BTRFS_FIRST_FREE_OBJECTID - EXT2_ROOT_INO)
+#define STRIPE_LEN (64 * 1024)
+#define EXT2_IMAGE_SUBVOL_OBJECTID BTRFS_FIRST_FREE_OBJECTID
+
+/*
+ * Open Ext2fs in readonly mode, read block allocation bitmap and
+ * inode bitmap into memory.
+ */
+static int open_ext2fs(const char *name, ext2_filsys *ret_fs)
+{
+	errcode_t ret;
+	ext2_filsys ext2_fs;
+	ext2_ino_t ino;
+	ret = ext2fs_open(name, 0, 0, 0, unix_io_manager, &ext2_fs);
+	if (ret) {
+		fprintf(stderr, "ext2fs_open: %s\n", error_message(ret));
+		goto fail;
+	}
+	ret = ext2fs_read_inode_bitmap(ext2_fs);
+	if (ret) {
+		fprintf(stderr, "ext2fs_read_inode_bitmap: %s\n",
+			error_message(ret));
+		goto fail;
+	}
+	ret = ext2fs_read_block_bitmap(ext2_fs);
+	if (ret) {
+		fprintf(stderr, "ext2fs_read_block_bitmap: %s\n",
+			error_message(ret));
+		goto fail;
+	}
+	/*
+	 * search each block group for a free inode. this set up
+	 * uninit block/inode bitmaps appropriately.
+	 */
+	ino = 1;
+	while (ino <= ext2_fs->super->s_inodes_count) {
+		ext2_ino_t foo;
+		ext2fs_new_inode(ext2_fs, ino, 0, NULL, &foo);
+		ino += EXT2_INODES_PER_GROUP(ext2_fs->super);
+	}
+
+	*ret_fs = ext2_fs;
+	return 0;
+fail:
+	return -1;
+}
+
+static int close_ext2fs(ext2_filsys fs)
+{
+	ext2fs_close(fs);
+	return 0;
+}
+
+static int ext2_alloc_block(ext2_filsys fs, u64 goal, u64 *block_ret)
+{
+	blk_t block;
+
+	if (!ext2fs_new_block(fs, goal, NULL, &block)) {
+		ext2fs_fast_mark_block_bitmap(fs->block_map, block);
+		*block_ret = block;
+		return 0;
+	}
+	return -ENOSPC;
+}
+
+static int ext2_free_block(ext2_filsys fs, u64 block)
+{
+	BUG_ON(block != (blk_t)block);
+	ext2fs_fast_unmark_block_bitmap(fs->block_map, block);
+	return 0;
+}
+
+static int cache_free_extents(struct btrfs_root *root, ext2_filsys ext2_fs)
+
+{
+	int i, ret = 0;
+	blk_t block;
+	u64 bytenr;
+	u64 blocksize = ext2_fs->blocksize;
+
+	block = ext2_fs->super->s_first_data_block;
+	for (; block < ext2_fs->super->s_blocks_count; block++) {
+		if (ext2fs_fast_test_block_bitmap(ext2_fs->block_map, block))
+			continue;
+		bytenr = block * blocksize;
+		ret = set_extent_dirty(&root->fs_info->free_space_cache,
+				       bytenr, bytenr + blocksize - 1, 0);
+		BUG_ON(ret);
+	}
+
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		bytenr &= ~((u64)STRIPE_LEN - 1);
+		if (bytenr >= blocksize * ext2_fs->super->s_blocks_count)
+			break;
+		clear_extent_dirty(&root->fs_info->free_space_cache, bytenr,
+				   bytenr + STRIPE_LEN - 1, 0);
+	}
+
+	clear_extent_dirty(&root->fs_info->free_space_cache,
+			   0, BTRFS_SUPER_INFO_OFFSET - 1, 0);
+
+	return 0;
+}
+
+static int custom_alloc_extent(struct btrfs_root *root, u64 num_bytes,
+			       u64 hint_byte, struct btrfs_key *ins)
+{
+	u64 start;
+	u64 end;
+	u64 last = hint_byte;
+	int ret;
+	int wrapped = 0;
+	struct btrfs_block_group_cache *cache;
+
+	while(1) {
+		ret = find_first_extent_bit(&root->fs_info->free_space_cache,
+					    last, &start, &end, EXTENT_DIRTY);
+		if (ret) {
+			if (wrapped++ == 0) {
+				last = 0;
+				continue;
+			} else {
+				goto fail;
+			}
+		}
+
+		start = max(last, start);
+		last = end + 1;
+		if (last - start < num_bytes)
+			continue;
+
+		last = start + num_bytes;
+		if (test_range_bit(&root->fs_info->pinned_extents,
+				   start, last - 1, EXTENT_DIRTY, 0))
+			continue;
+
+		cache = btrfs_lookup_block_group(root->fs_info, start);
+		BUG_ON(!cache);
+		if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM ||
+		    last > cache->key.objectid + cache->key.offset) {
+			last = cache->key.objectid + cache->key.offset;
+			continue;
+		}
+
+		clear_extent_dirty(&root->fs_info->free_space_cache,
+				   start, start + num_bytes - 1, 0);
+
+		ins->objectid = start;
+		ins->offset = num_bytes;
+		ins->type = BTRFS_EXTENT_ITEM_KEY;
+		return 0;
+	}
+fail:
+	fprintf(stderr, "not enough free space\n");
+	return -ENOSPC;
+}
+
+static int intersect_with_sb(u64 bytenr, u64 num_bytes)
+{
+	int i;
+	u64 offset;
+
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		offset = btrfs_sb_offset(i);
+		offset &= ~((u64)STRIPE_LEN - 1);
+
+		if (bytenr < offset + STRIPE_LEN &&
+		    bytenr + num_bytes > offset)
+			return 1;
+	}
+	return 0;
+}
+
+static int custom_free_extent(struct btrfs_root *root, u64 bytenr,
+			      u64 num_bytes)
+{
+	return intersect_with_sb(bytenr, num_bytes);
+}
+
+struct btrfs_extent_ops extent_ops = {
+	.alloc_extent = custom_alloc_extent,
+	.free_extent = custom_free_extent,
+};
+
+struct dir_iterate_data {
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root;
+	struct btrfs_inode_item *inode;
+	u64 objectid;
+	u64 index_cnt;
+	u64 parent;
+	int errcode;
+};
+
+static u8 filetype_conversion_table[EXT2_FT_MAX] = {
+	[EXT2_FT_UNKNOWN]	= BTRFS_FT_UNKNOWN,
+	[EXT2_FT_REG_FILE]	= BTRFS_FT_REG_FILE,
+	[EXT2_FT_DIR]		= BTRFS_FT_DIR,
+	[EXT2_FT_CHRDEV]	= BTRFS_FT_CHRDEV,
+	[EXT2_FT_BLKDEV]	= BTRFS_FT_BLKDEV,
+	[EXT2_FT_FIFO]		= BTRFS_FT_FIFO,
+	[EXT2_FT_SOCK]		= BTRFS_FT_SOCK,
+	[EXT2_FT_SYMLINK]	= BTRFS_FT_SYMLINK,
+};
+
+static int dir_iterate_proc(ext2_ino_t dir, int entry,
+			    struct ext2_dir_entry *dirent,
+			    int offset, int blocksize,
+			    char *buf,void *priv_data)
+{
+	int ret;
+	int file_type;
+	u64 objectid;
+        u64 inode_size;
+	char dotdot[] = "..";
+	struct btrfs_key location;
+	struct dir_iterate_data *idata = (struct dir_iterate_data *)priv_data;
+	int name_len;
+
+	name_len = dirent->name_len & 0xFF;
+
+	objectid = dirent->inode + INO_OFFSET;
+	if (!strncmp(dirent->name, dotdot, name_len)) {
+		if (name_len == 2) {
+			BUG_ON(idata->parent != 0);
+			idata->parent = objectid;
+		}
+		return 0;
+	}
+	if (dirent->inode < EXT2_GOOD_OLD_FIRST_INO)
+		return 0;
+
+	location.objectid = objectid;
+	location.offset = 0;
+	btrfs_set_key_type(&location, BTRFS_INODE_ITEM_KEY);
+
+	file_type = dirent->name_len >> 8;
+	BUG_ON(file_type > EXT2_FT_SYMLINK);
+	ret = btrfs_insert_dir_item(idata->trans, idata->root,
+				    dirent->name, name_len,
+				    idata->objectid, &location,
+				    filetype_conversion_table[file_type],
+				    idata->index_cnt);
+	if (ret)
+		goto fail;
+	ret = btrfs_insert_inode_ref(idata->trans, idata->root,
+				     dirent->name, name_len,
+				     objectid, idata->objectid,
+				     idata->index_cnt);
+	if (ret)
+		goto fail;
+	idata->index_cnt++;
+	inode_size = btrfs_stack_inode_size(idata->inode) +
+		     name_len * 2;
+	btrfs_set_stack_inode_size(idata->inode, inode_size);
+	return 0;
+fail:
+	idata->errcode = ret;
+	return BLOCK_ABORT;
+}
+
+static int create_dir_entries(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root, u64 objectid,
+			      struct btrfs_inode_item *btrfs_inode,
+			      ext2_filsys ext2_fs, ext2_ino_t ext2_ino)
+{
+	int ret;
+	errcode_t err;
+	struct dir_iterate_data data = {
+		.trans		= trans,
+		.root		= root,
+		.inode		= btrfs_inode,
+		.objectid	= objectid,
+		.index_cnt	= 2,
+		.parent		= 0,
+		.errcode	= 0,
+	};
+
+	err = ext2fs_dir_iterate2(ext2_fs, ext2_ino, 0, NULL,
+				  dir_iterate_proc, &data);
+	if (err)
+		goto error;
+	ret = data.errcode;
+	if (ret == 0 && data.parent == objectid) {
+		ret = btrfs_insert_inode_ref(trans, root, "..", 2,
+					     objectid, objectid, 0);
+	}
+	return ret;
+error:
+	fprintf(stderr, "ext2fs_dir_iterate2: %s\n", error_message(err));
+	return -1;
+}
+
+static int read_disk_extent(struct btrfs_root *root, u64 bytenr,
+		            u32 num_bytes, char *buffer)
+{
+	int ret;
+	struct btrfs_fs_devices *fs_devs = root->fs_info->fs_devices;
+
+	ret = pread(fs_devs->latest_bdev, buffer, num_bytes, bytenr);
+	if (ret != num_bytes)
+		goto fail;
+	ret = 0;
+fail:
+	if (ret > 0)
+		ret = -1;
+	return ret;
+}
+/*
+ * Record a file extent. Do all the required works, such as inserting
+ * file extent item, inserting extent item and backref item into extent
+ * tree and updating block accounting.
+ */
+static int record_file_extent(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root, u64 objectid,
+			      struct btrfs_inode_item *inode,
+			      u64 file_pos, u64 disk_bytenr,
+			      u64 num_bytes, int checksum)
+{
+	int ret;
+	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_root *extent_root = info->extent_root;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key ins_key;
+	struct btrfs_path path;
+	struct btrfs_extent_item *ei;
+	u32 blocksize = root->sectorsize;
+	u64 nbytes;
+
+	if (disk_bytenr == 0) {
+		ret = btrfs_insert_file_extent(trans, root, objectid,
+						file_pos, disk_bytenr,
+						num_bytes, num_bytes);
+		return ret;
+	}
+
+	btrfs_init_path(&path);
+
+	if (checksum) {
+		u64 offset;
+		char *buffer;
+
+		ret = -ENOMEM;
+		buffer = malloc(blocksize);
+		if (!buffer)
+			goto fail;
+		for (offset = 0; offset < num_bytes; offset += blocksize) {
+			ret = read_disk_extent(root, disk_bytenr + offset,
+						blocksize, buffer);
+			if (ret)
+				break;
+			ret = btrfs_csum_file_block(trans,
+						    root->fs_info->csum_root,
+						    disk_bytenr + num_bytes,
+						    disk_bytenr + offset,
+						    buffer, blocksize);
+			if (ret)
+				break;
+		}
+		free(buffer);
+		if (ret)
+			goto fail;
+	}
+
+	ins_key.objectid = objectid;
+	ins_key.offset = file_pos;
+	btrfs_set_key_type(&ins_key, BTRFS_EXTENT_DATA_KEY);
+	ret = btrfs_insert_empty_item(trans, root, &path, &ins_key,
+				      sizeof(*fi));
+	if (ret)
+		goto fail;
+	leaf = path.nodes[0];
+	fi = btrfs_item_ptr(leaf, path.slots[0],
+			    struct btrfs_file_extent_item);
+	btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+	btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
+	btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
+	btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
+	btrfs_set_file_extent_offset(leaf, fi, 0);
+	btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+	btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+	btrfs_set_file_extent_compression(leaf, fi, 0);
+	btrfs_set_file_extent_encryption(leaf, fi, 0);
+	btrfs_set_file_extent_other_encoding(leaf, fi, 0);
+	btrfs_mark_buffer_dirty(leaf);
+
+	nbytes = btrfs_stack_inode_nbytes(inode) + num_bytes;
+	btrfs_set_stack_inode_nbytes(inode, nbytes);
+
+	btrfs_release_path(root, &path);
+
+	ins_key.objectid = disk_bytenr;
+	ins_key.offset = num_bytes;
+	ins_key.type = BTRFS_EXTENT_ITEM_KEY;
+
+	ret = btrfs_insert_empty_item(trans, extent_root, &path,
+				      &ins_key, sizeof(*ei));
+	if (ret == 0) {
+		leaf = path.nodes[0];
+		ei = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_extent_item);
+
+		btrfs_set_extent_refs(leaf, ei, 0);
+		btrfs_set_extent_generation(leaf, ei, 0);
+		btrfs_set_extent_flags(leaf, ei, BTRFS_EXTENT_FLAG_DATA);
+
+		btrfs_mark_buffer_dirty(leaf);
+
+		ret = btrfs_update_block_group(trans, root, disk_bytenr,
+					       num_bytes, 1, 0);
+		if (ret)
+			goto fail;
+	} else if (ret != -EEXIST) {
+		goto fail;
+	}
+	btrfs_extent_post_op(trans, extent_root);
+
+	ret = btrfs_inc_extent_ref(trans, root, disk_bytenr, num_bytes, 0,
+				   root->root_key.objectid,
+				   objectid, file_pos);
+	if (ret)
+		goto fail;
+	ret = 0;
+fail:
+	btrfs_release_path(root, &path);
+	return ret;
+}
+
+static int record_file_blocks(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root, u64 objectid,
+			      struct btrfs_inode_item *inode,
+			      u64 file_block, u64 disk_block,
+			      u64 num_blocks, int checksum)
+{
+	u64 file_pos = file_block * root->sectorsize;
+	u64 disk_bytenr = disk_block * root->sectorsize;
+	u64 num_bytes = num_blocks * root->sectorsize;
+	return record_file_extent(trans, root, objectid, inode, file_pos,
+				  disk_bytenr, num_bytes, checksum);
+}
+
+struct blk_iterate_data {
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root;
+	struct btrfs_inode_item *inode;
+	u64 objectid;
+	u64 first_block;
+	u64 disk_block;
+	u64 num_blocks;
+	u64 boundary;
+	int checksum;
+	int errcode;
+};
+
+static int block_iterate_proc(ext2_filsys ext2_fs,
+			      u64 disk_block, u64 file_block,
+		              struct blk_iterate_data *idata)
+{
+	int ret;
+	int sb_region;
+	int do_barrier;
+	struct btrfs_root *root = idata->root;
+	struct btrfs_trans_handle *trans = idata->trans;
+	struct btrfs_block_group_cache *cache;
+	u64 bytenr = disk_block * root->sectorsize;
+
+	sb_region = intersect_with_sb(bytenr, root->sectorsize);
+	do_barrier = sb_region || disk_block >= idata->boundary;
+	if ((idata->num_blocks > 0 && do_barrier) ||
+	    (file_block > idata->first_block + idata->num_blocks) ||
+	    (disk_block != idata->disk_block + idata->num_blocks)) {
+		if (idata->num_blocks > 0) {
+			ret = record_file_blocks(trans, root, idata->objectid,
+					idata->inode, idata->first_block,
+					idata->disk_block, idata->num_blocks,
+					idata->checksum);
+			if (ret)
+				goto fail;
+			idata->first_block += idata->num_blocks;
+			idata->num_blocks = 0;
+		}
+		if (file_block > idata->first_block) {
+			ret = record_file_blocks(trans, root, idata->objectid,
+					idata->inode, idata->first_block,
+					0, file_block - idata->first_block,
+					idata->checksum);
+			if (ret)
+				goto fail;
+		}
+
+		if (sb_region) {
+			bytenr += STRIPE_LEN - 1;
+			bytenr &= ~((u64)STRIPE_LEN - 1);
+		} else {
+			cache = btrfs_lookup_block_group(root->fs_info, bytenr);
+			BUG_ON(!cache);
+			bytenr = cache->key.objectid + cache->key.offset;
+		}
+
+		idata->first_block = file_block;
+		idata->disk_block = disk_block;
+		idata->boundary = bytenr / root->sectorsize;
+	}
+	idata->num_blocks++;
+	return 0;
+fail:
+	idata->errcode = ret;
+	return BLOCK_ABORT;
+}
+
+static int __block_iterate_proc(ext2_filsys fs, blk_t *blocknr,
+			        e2_blkcnt_t blockcnt, blk_t ref_block,
+			        int ref_offset, void *priv_data)
+{
+	struct blk_iterate_data *idata;
+	idata = (struct blk_iterate_data *)priv_data;
+	return block_iterate_proc(fs, *blocknr, blockcnt, idata);
+}
+
+/*
+ * traverse file's data blocks, record these data blocks as file extents.
+ */
+static int create_file_extents(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root, u64 objectid,
+			       struct btrfs_inode_item *btrfs_inode,
+			       ext2_filsys ext2_fs, ext2_ino_t ext2_ino,
+			       int datacsum, int packing)
+{
+	int ret;
+	char *buffer = NULL;
+	errcode_t err;
+	u32 last_block;
+	u32 sectorsize = root->sectorsize;
+	u64 inode_size = btrfs_stack_inode_size(btrfs_inode);
+	struct blk_iterate_data data = {
+		.trans		= trans,
+		.root		= root,
+		.inode		= btrfs_inode,
+		.objectid	= objectid,
+		.first_block	= 0,
+		.disk_block	= 0,
+		.num_blocks	= 0,
+		.boundary	= (u64)-1,
+		.checksum	= datacsum,
+		.errcode	= 0,
+	};
+	err = ext2fs_block_iterate2(ext2_fs, ext2_ino, BLOCK_FLAG_DATA_ONLY,
+				    NULL, __block_iterate_proc, &data);
+	if (err)
+		goto error;
+	ret = data.errcode;
+	if (ret)
+		goto fail;
+	if (packing && data.first_block == 0 && data.num_blocks > 0 &&
+	    inode_size <= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
+		u64 num_bytes = data.num_blocks * sectorsize;
+		u64 disk_bytenr = data.disk_block * sectorsize;
+		u64 nbytes;
+
+		buffer = malloc(num_bytes);
+		if (!buffer)
+			return -ENOMEM;
+		ret = read_disk_extent(root, disk_bytenr, num_bytes, buffer);
+		if (ret)
+			goto fail;
+		if (num_bytes > inode_size)
+			num_bytes = inode_size;
+		ret = btrfs_insert_inline_extent(trans, root, objectid,
+						 0, buffer, num_bytes);
+		if (ret)
+			goto fail;
+		nbytes = btrfs_stack_inode_nbytes(btrfs_inode) + num_bytes;
+		btrfs_set_stack_inode_nbytes(btrfs_inode, nbytes);
+	} else if (data.num_blocks > 0) {
+		ret = record_file_blocks(trans, root, objectid, btrfs_inode,
+					 data.first_block, data.disk_block,
+					 data.num_blocks, data.checksum);
+		if (ret)
+			goto fail;
+	}
+	data.first_block += data.num_blocks;
+	last_block = (inode_size + sectorsize - 1) / sectorsize;
+	if (last_block > data.first_block) {
+		ret = record_file_blocks(trans, root, objectid, btrfs_inode,
+					 data.first_block, 0, last_block -
+					 data.first_block, data.checksum);
+	}
+fail:
+	if (buffer)
+		free(buffer);
+	return ret;
+error:
+	fprintf(stderr, "ext2fs_block_iterate2: %s\n", error_message(err));
+	return -1;
+}
+
+static int create_symbol_link(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root, u64 objectid,
+			      struct btrfs_inode_item *btrfs_inode,
+			      ext2_filsys ext2_fs, ext2_ino_t ext2_ino,
+			      struct ext2_inode *ext2_inode)
+{
+	int ret;
+	char *pathname;
+	u64 inode_size = btrfs_stack_inode_size(btrfs_inode);
+	if (ext2fs_inode_data_blocks(ext2_fs, ext2_inode)) {
+		btrfs_set_stack_inode_size(btrfs_inode, inode_size + 1);
+		ret = create_file_extents(trans, root, objectid, btrfs_inode,
+					  ext2_fs, ext2_ino, 1, 1);
+		btrfs_set_stack_inode_size(btrfs_inode, inode_size);
+		return ret;
+	}
+
+	pathname = (char *)&(ext2_inode->i_block[0]);
+	BUG_ON(pathname[inode_size] != 0);
+	ret = btrfs_insert_inline_extent(trans, root, objectid, 0,
+					 pathname, inode_size + 1);
+	btrfs_set_stack_inode_nbytes(btrfs_inode, inode_size + 1);
+	return ret;
+}
+
+/*
+ * Following xattr/acl related codes are based on codes in
+ * fs/ext3/xattr.c and fs/ext3/acl.c
+ */
+#define EXT2_XATTR_BHDR(ptr) ((struct ext2_ext_attr_header *)(ptr))
+#define EXT2_XATTR_BFIRST(ptr) \
+	((struct ext2_ext_attr_entry *)(EXT2_XATTR_BHDR(ptr) + 1))
+#define EXT2_XATTR_IHDR(inode) \
+	((struct ext2_ext_attr_header *) ((void *)(inode) + \
+		EXT2_GOOD_OLD_INODE_SIZE + (inode)->i_extra_isize))
+#define EXT2_XATTR_IFIRST(inode) \
+	((struct ext2_ext_attr_entry *) ((void *)EXT2_XATTR_IHDR(inode) + \
+		sizeof(EXT2_XATTR_IHDR(inode)->h_magic)))
+
+static int ext2_xattr_check_names(struct ext2_ext_attr_entry *entry,
+				  const void *end)
+{
+	struct ext2_ext_attr_entry *next;
+
+	while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
+		next = EXT2_EXT_ATTR_NEXT(entry);
+		if ((void *)next >= end)
+			return -EIO;
+		entry = next;
+	}
+	return 0;
+}
+
+static int ext2_xattr_check_block(const char *buf, size_t size)
+{
+	int error;
+	struct ext2_ext_attr_header *header = EXT2_XATTR_BHDR(buf);
+
+	if (header->h_magic != EXT2_EXT_ATTR_MAGIC ||
+	    header->h_blocks != 1)
+		return -EIO;
+	error = ext2_xattr_check_names(EXT2_XATTR_BFIRST(buf), buf + size);
+	return error;
+}
+
+static int ext2_xattr_check_entry(struct ext2_ext_attr_entry *entry,
+				  size_t size)
+{
+	size_t value_size = entry->e_value_size;
+
+	if (entry->e_value_block != 0 || value_size > size ||
+	    entry->e_value_offs + value_size > size)
+		return -EIO;
+	return 0;
+}
+
+#define EXT2_ACL_VERSION	0x0001
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} ext2_acl_entry;
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+} ext2_acl_entry_short;
+
+typedef struct {
+	__le32		a_version;
+} ext2_acl_header;
+
+static inline int ext2_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext2_acl_header);
+	s = size - 4 * sizeof(ext2_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext2_acl_entry_short))
+			return -1;
+		return size / sizeof(ext2_acl_entry_short);
+	} else {
+		if (s % sizeof(ext2_acl_entry))
+			return -1;
+		return s / sizeof(ext2_acl_entry) + 4;
+	}
+}
+
+#define ACL_EA_VERSION		0x0002
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} acl_ea_entry;
+
+typedef struct {
+	__le32		a_version;
+	acl_ea_entry	a_entries[0];
+} acl_ea_header;
+
+static inline size_t acl_ea_size(int count)
+{
+	return sizeof(acl_ea_header) + count * sizeof(acl_ea_entry);
+}
+
+static int ext2_acl_to_xattr(void *dst, const void *src,
+			     size_t dst_size, size_t src_size)
+{
+	int i, count;
+	const void *end = src + src_size;
+	acl_ea_header *ext_acl = (acl_ea_header *)dst;
+	acl_ea_entry *dst_entry = ext_acl->a_entries;
+	ext2_acl_entry *src_entry;
+
+	if (src_size < sizeof(ext2_acl_header))
+		goto fail;
+	if (((ext2_acl_header *)src)->a_version !=
+	    cpu_to_le32(EXT2_ACL_VERSION))
+		goto fail;
+	src += sizeof(ext2_acl_header);
+	count = ext2_acl_count(src_size);
+	if (count <= 0)
+		goto fail;
+
+	BUG_ON(dst_size < acl_ea_size(count));
+	ext_acl->a_version = cpu_to_le32(ACL_EA_VERSION);
+	for (i = 0; i < count; i++, dst_entry++) {
+		src_entry = (ext2_acl_entry *)src;
+		if (src + sizeof(ext2_acl_entry_short) > end)
+			goto fail;
+		dst_entry->e_tag = src_entry->e_tag;
+		dst_entry->e_perm = src_entry->e_perm;
+		switch (le16_to_cpu(src_entry->e_tag)) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			src += sizeof(ext2_acl_entry_short);
+			dst_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+			break;
+		case ACL_USER:
+		case ACL_GROUP:
+			src += sizeof(ext2_acl_entry);
+			if (src > end)
+				goto fail;
+			dst_entry->e_id = src_entry->e_id;
+			break;
+		default:
+			goto fail;
+		}
+	}
+	if (src != end)
+		goto fail;
+	return 0;
+fail:
+	return -EINVAL;
+}
+
+static char *xattr_prefix_table[] = {
+	[1] =	"user.",
+	[2] =	"system.posix_acl_access",
+	[3] =	"system.posix_acl_default",
+	[4] =	"trusted.",
+	[6] =	"security.",
+};
+
+static int copy_single_xattr(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root, u64 objectid,
+			     struct ext2_ext_attr_entry *entry,
+			     const void *data, u32 datalen)
+{
+	int ret = 0;
+	int name_len;
+	int name_index;
+	void *databuf = NULL;
+	char namebuf[XATTR_NAME_MAX + 1];
+
+	name_index = entry->e_name_index;
+	if (name_index >= ARRAY_SIZE(xattr_prefix_table) ||
+	    xattr_prefix_table[name_index] == NULL)
+		return -EOPNOTSUPP;
+	name_len = strlen(xattr_prefix_table[name_index]) +
+		   entry->e_name_len;
+	if (name_len >= sizeof(namebuf))
+		return -ERANGE;
+
+	if (name_index == 2 || name_index == 3) {
+		size_t bufsize = acl_ea_size(ext2_acl_count(datalen));
+		databuf = malloc(bufsize);
+		if (!databuf)
+		       return -ENOMEM;
+		ret = ext2_acl_to_xattr(databuf, data, bufsize, datalen);
+		if (ret)
+			goto out;
+		data = databuf;
+		datalen = bufsize;
+	}
+	strncpy(namebuf, xattr_prefix_table[name_index], XATTR_NAME_MAX);
+	strncat(namebuf, EXT2_EXT_ATTR_NAME(entry), entry->e_name_len);
+	if (name_len + datalen > BTRFS_LEAF_DATA_SIZE(root) -
+	    sizeof(struct btrfs_item) - sizeof(struct btrfs_dir_item)) {
+		fprintf(stderr, "skip large xattr on inode %Lu name %.*s\n",
+			objectid - INO_OFFSET, name_len, namebuf);
+		goto out;
+	}
+	ret = btrfs_insert_xattr_item(trans, root, namebuf, name_len,
+				      data, datalen, objectid);
+out:
+	if (databuf)
+		free(databuf);
+	return ret;
+}
+
+static int copy_extended_attrs(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root, u64 objectid,
+			       struct btrfs_inode_item *btrfs_inode,
+			       ext2_filsys ext2_fs, ext2_ino_t ext2_ino)
+{
+	int ret = 0;
+	int inline_ea = 0;
+	errcode_t err;
+	u32 datalen;
+	u32 block_size = ext2_fs->blocksize;
+	u32 inode_size = EXT2_INODE_SIZE(ext2_fs->super);
+	struct ext2_inode_large *ext2_inode;
+	struct ext2_ext_attr_entry *entry;
+	void *data;
+	char *buffer = NULL;
+	char inode_buf[EXT2_GOOD_OLD_INODE_SIZE];
+
+	if (inode_size <= EXT2_GOOD_OLD_INODE_SIZE) {
+		ext2_inode = (struct ext2_inode_large *)inode_buf;
+	} else {
+		ext2_inode = (struct ext2_inode_large *)malloc(inode_size);
+		if (!ext2_inode)
+		       return -ENOMEM;
+	}
+	err = ext2fs_read_inode_full(ext2_fs, ext2_ino, (void *)ext2_inode,
+				     inode_size);
+	if (err) {
+		fprintf(stderr, "ext2fs_read_inode_full: %s\n",
+			error_message(err));
+		ret = -1;
+		goto out;
+	}
+
+	if (ext2_ino > ext2_fs->super->s_first_ino &&
+	    inode_size > EXT2_GOOD_OLD_INODE_SIZE) {
+		if (EXT2_GOOD_OLD_INODE_SIZE +
+		    ext2_inode->i_extra_isize > inode_size) {
+			ret = -EIO;
+			goto out;
+		}
+		if (ext2_inode->i_extra_isize != 0 &&
+		    EXT2_XATTR_IHDR(ext2_inode)->h_magic ==
+		    EXT2_EXT_ATTR_MAGIC) {
+			inline_ea = 1;
+		}
+	}
+	if (inline_ea) {
+		int total;
+		void *end = (void *)ext2_inode + inode_size;
+		entry = EXT2_XATTR_IFIRST(ext2_inode);
+		total = end - (void *)entry;
+		ret = ext2_xattr_check_names(entry, end);
+		if (ret)
+			goto out;
+		while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
+			ret = ext2_xattr_check_entry(entry, total);
+			if (ret)
+				goto out;
+			data = (void *)EXT2_XATTR_IFIRST(ext2_inode) +
+				entry->e_value_offs;
+			datalen = entry->e_value_size;
+			ret = copy_single_xattr(trans, root, objectid,
+						entry, data, datalen);
+			if (ret)
+				goto out;
+			entry = EXT2_EXT_ATTR_NEXT(entry);
+		}
+	}
+
+	if (ext2_inode->i_file_acl == 0)
+		goto out;
+
+	buffer = malloc(block_size);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	err = ext2fs_read_ext_attr(ext2_fs, ext2_inode->i_file_acl, buffer);
+	if (err) {
+		fprintf(stderr, "ext2fs_read_ext_attr: %s\n",
+			error_message(err));
+		ret = -1;
+		goto out;
+	}
+	ret = ext2_xattr_check_block(buffer, block_size);
+	if (ret)
+		goto out;
+
+	entry = EXT2_XATTR_BFIRST(buffer);
+	while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
+		ret = ext2_xattr_check_entry(entry, block_size);
+		if (ret)
+			goto out;
+		data = buffer + entry->e_value_offs;
+		datalen = entry->e_value_size;
+		ret = copy_single_xattr(trans, root, objectid,
+					entry, data, datalen);
+		if (ret)
+			goto out;
+		entry = EXT2_EXT_ATTR_NEXT(entry);
+	}
+out:
+	if (buffer != NULL)
+		free(buffer);
+	if ((void *)ext2_inode != inode_buf)
+		free(ext2_inode);
+	return ret;
+}
+#define MINORBITS	20
+#define MKDEV(ma, mi)	(((ma) << MINORBITS) | (mi))
+
+static inline dev_t old_decode_dev(u16 val)
+{
+	return MKDEV((val >> 8) & 255, val & 255);
+}
+
+static inline dev_t new_decode_dev(u32 dev)
+{
+	unsigned major = (dev & 0xfff00) >> 8;
+	unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
+	return MKDEV(major, minor);
+}
+
+static int copy_inode_item(struct btrfs_inode_item *dst,
+			   struct ext2_inode *src, u32 blocksize)
+{
+	btrfs_set_stack_inode_generation(dst, 1);
+	btrfs_set_stack_inode_size(dst, src->i_size);
+	btrfs_set_stack_inode_nbytes(dst, 0);
+	btrfs_set_stack_inode_block_group(dst, 0);
+	btrfs_set_stack_inode_nlink(dst, src->i_links_count);
+	btrfs_set_stack_inode_uid(dst, src->i_uid | (src->i_uid_high << 16));
+	btrfs_set_stack_inode_gid(dst, src->i_gid | (src->i_gid_high << 16));
+	btrfs_set_stack_inode_mode(dst, src->i_mode);
+	btrfs_set_stack_inode_rdev(dst, 0);
+	btrfs_set_stack_inode_flags(dst, 0);
+	btrfs_set_stack_timespec_sec(&dst->atime, src->i_atime);
+	btrfs_set_stack_timespec_nsec(&dst->atime, 0);
+	btrfs_set_stack_timespec_sec(&dst->ctime, src->i_ctime);
+	btrfs_set_stack_timespec_nsec(&dst->ctime, 0);
+	btrfs_set_stack_timespec_sec(&dst->mtime, src->i_mtime);
+	btrfs_set_stack_timespec_nsec(&dst->mtime, 0);
+	btrfs_set_stack_timespec_sec(&dst->otime, 0);
+	btrfs_set_stack_timespec_nsec(&dst->otime, 0);
+
+	if (S_ISDIR(src->i_mode)) {
+		btrfs_set_stack_inode_size(dst, 0);
+		btrfs_set_stack_inode_nlink(dst, 1);
+	}
+	if (S_ISREG(src->i_mode)) {
+		btrfs_set_stack_inode_size(dst, (u64)src->i_size_high << 32 |
+					   (u64)src->i_size);
+	}
+	if (!S_ISREG(src->i_mode) && !S_ISDIR(src->i_mode) &&
+	    !S_ISLNK(src->i_mode)) {
+		if (src->i_block[0]) {
+			btrfs_set_stack_inode_rdev(dst,
+				old_decode_dev(src->i_block[0]));
+		} else {
+			btrfs_set_stack_inode_rdev(dst,
+				new_decode_dev(src->i_block[1]));
+		}
+	}
+	return 0;
+}
+
+/*
+ * copy a single inode. do all the required works, such as cloning
+ * inode item, creating file extents and creating directory entries.
+ */
+static int copy_single_inode(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root, u64 objectid,
+			     ext2_filsys ext2_fs, ext2_ino_t ext2_ino,
+			     struct ext2_inode *ext2_inode,
+			     int datacsum, int packing, int noxattr)
+{
+	int ret;
+	struct btrfs_key inode_key;
+	struct btrfs_inode_item btrfs_inode;
+
+	if (ext2_inode->i_links_count == 0)
+		return 0;
+
+	copy_inode_item(&btrfs_inode, ext2_inode, ext2_fs->blocksize);
+	if (!datacsum && S_ISREG(ext2_inode->i_mode)) {
+		u32 flags = btrfs_stack_inode_flags(&btrfs_inode) |
+			    BTRFS_INODE_NODATASUM;
+		btrfs_set_stack_inode_flags(&btrfs_inode, flags);
+	}
+
+	switch (ext2_inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		ret = create_file_extents(trans, root, objectid, &btrfs_inode,
+					ext2_fs, ext2_ino, datacsum, packing);
+		break;
+	case S_IFDIR:
+		ret = create_dir_entries(trans, root, objectid, &btrfs_inode,
+					 ext2_fs, ext2_ino);
+		break;
+	case S_IFLNK:
+		ret = create_symbol_link(trans, root, objectid, &btrfs_inode,
+					 ext2_fs, ext2_ino, ext2_inode);
+		break;
+	default:
+		ret = 0;
+		break;
+	}
+	if (ret)
+		return ret;
+
+	if (!noxattr) {
+		ret = copy_extended_attrs(trans, root, objectid, &btrfs_inode,
+					  ext2_fs, ext2_ino);
+		if (ret)
+			return ret;
+	}
+	inode_key.objectid = objectid;
+	inode_key.offset = 0;
+	btrfs_set_key_type(&inode_key, BTRFS_INODE_ITEM_KEY);
+	ret = btrfs_insert_inode(trans, root, objectid, &btrfs_inode);
+	return ret;
+}
+
+static int copy_disk_extent(struct btrfs_root *root, u64 dst_bytenr,
+		            u64 src_bytenr, u32 num_bytes)
+{
+	int ret;
+	char *buffer;
+	struct btrfs_fs_devices *fs_devs = root->fs_info->fs_devices;
+
+	buffer = malloc(num_bytes);
+	if (!buffer)
+		return -ENOMEM;
+	ret = pread(fs_devs->latest_bdev, buffer, num_bytes, src_bytenr);
+	if (ret != num_bytes)
+		goto fail;
+	ret = pwrite(fs_devs->latest_bdev, buffer, num_bytes, dst_bytenr);
+	if (ret != num_bytes)
+		goto fail;
+	ret = 0;
+fail:
+	free(buffer);
+	if (ret > 0)
+		ret = -1;
+	return ret;
+}
+/*
+ * scan ext2's inode bitmap and copy all used inodes.
+ */
+static int copy_inodes(struct btrfs_root *root, ext2_filsys ext2_fs,
+		       int datacsum, int packing, int noxattr)
+{
+	int ret;
+	errcode_t err;
+	ext2_inode_scan ext2_scan;
+	struct ext2_inode ext2_inode;
+	ext2_ino_t ext2_ino;
+	u64 objectid;
+	struct btrfs_trans_handle *trans;
+
+	trans = btrfs_start_transaction(root, 1);
+	if (!trans)
+		return -ENOMEM;
+	err = ext2fs_open_inode_scan(ext2_fs, 0, &ext2_scan);
+	if (err) {
+		fprintf(stderr, "ext2fs_open_inode_scan: %s\n", error_message(err));
+		return -1;
+	}
+	while (!(err = ext2fs_get_next_inode(ext2_scan, &ext2_ino,
+					     &ext2_inode))) {
+		/* no more inodes */
+		if (ext2_ino == 0)
+			break;
+		/* skip special inode in ext2fs */
+		if (ext2_ino < EXT2_GOOD_OLD_FIRST_INO &&
+		    ext2_ino != EXT2_ROOT_INO)
+			continue;
+		objectid = ext2_ino + INO_OFFSET;
+		ret = copy_single_inode(trans, root,
+					objectid, ext2_fs, ext2_ino,
+					&ext2_inode, datacsum, packing,
+					noxattr);
+		if (ret)
+			return ret;
+		if (trans->blocks_used >= 4096) {
+			ret = btrfs_commit_transaction(trans, root);
+			BUG_ON(ret);
+			trans = btrfs_start_transaction(root, 1);
+			BUG_ON(!trans);
+		}
+	}
+	if (err) {
+		fprintf(stderr, "ext2fs_get_next_inode: %s\n", error_message(err));
+		return -1;
+	}
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+
+	return ret;
+}
+
+/*
+ * Construct a range of ext2fs image file.
+ * scan block allocation bitmap, find all blocks used by the ext2fs
+ * in this range and create file extents that point to these blocks.
+ *
+ * Note: Before calling the function, no file extent points to blocks
+ * 	 in this range
+ */
+static int create_image_file_range(struct btrfs_trans_handle *trans,
+				   struct btrfs_root *root, u64 objectid,
+				   struct btrfs_inode_item *inode,
+				   u64 start_byte, u64 end_byte,
+				   ext2_filsys ext2_fs)
+{
+	u32 blocksize = ext2_fs->blocksize;
+	u32 block = start_byte / blocksize;
+	u32 last_block = (end_byte + blocksize - 1) / blocksize;
+	int ret = 0;
+	struct blk_iterate_data data = {
+		.trans		= trans,
+		.root		= root,
+		.inode		= inode,
+		.objectid	= objectid,
+		.first_block	= block,
+		.disk_block	= 0,
+		.num_blocks	= 0,
+		.boundary	= (u64)-1,
+		.checksum 	= 0,
+		.errcode	= 0,
+	};
+	for (; start_byte < end_byte; block++, start_byte += blocksize) {
+		if (!ext2fs_fast_test_block_bitmap(ext2_fs->block_map, block))
+			continue;
+		ret = block_iterate_proc(NULL, block, block, &data);
+		if (ret & BLOCK_ABORT) {
+			ret = data.errcode;
+			goto fail;
+		}
+	}
+	if (data.num_blocks > 0) {
+		ret = record_file_blocks(trans, root, objectid, inode,
+					 data.first_block, data.disk_block,
+					 data.num_blocks, 0);
+		if (ret)
+			goto fail;
+		data.first_block += data.num_blocks;
+	}
+	if (last_block > data.first_block) {
+		ret = record_file_blocks(trans, root, objectid, inode,
+					 data.first_block, 0, last_block -
+					 data.first_block, 0);
+		if (ret)
+			goto fail;
+	}
+fail:
+	return ret;
+}
+/*
+ * Create the ext2fs image file.
+ */
+static int create_ext2_image(struct btrfs_root *root, ext2_filsys ext2_fs,
+			     const char *name)
+{
+	int ret;
+	struct btrfs_key key;
+	struct btrfs_key location;
+	struct btrfs_path path;
+	struct btrfs_inode_item btrfs_inode;
+	struct btrfs_inode_item *inode_item;
+	struct extent_buffer *leaf;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_root *extent_root = fs_info->extent_root;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_extent_item *ei;
+	struct btrfs_extent_inline_ref *iref;
+	struct btrfs_extent_data_ref *dref;
+	u64 bytenr;
+	u64 num_bytes;
+	u64 objectid;
+	u64 last_byte;
+	u64 first_free;
+	u64 total_bytes;
+	u32 sectorsize = root->sectorsize;
+
+	total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
+	first_free =  BTRFS_SUPER_INFO_OFFSET + sectorsize * 2 - 1;
+	first_free &= ~((u64)sectorsize - 1);
+
+	memset(&btrfs_inode, 0, sizeof(btrfs_inode));
+	btrfs_set_stack_inode_generation(&btrfs_inode, 1);
+	btrfs_set_stack_inode_size(&btrfs_inode, total_bytes);
+	btrfs_set_stack_inode_nlink(&btrfs_inode, 1);
+	btrfs_set_stack_inode_nbytes(&btrfs_inode, 0);
+	btrfs_set_stack_inode_mode(&btrfs_inode, S_IFREG | 0400);
+	btrfs_set_stack_inode_flags(&btrfs_inode, BTRFS_INODE_NODATASUM |
+				    BTRFS_INODE_READONLY);
+	btrfs_init_path(&path);
+	trans = btrfs_start_transaction(root, 1);
+	BUG_ON(!trans);
+
+	objectid = btrfs_root_dirid(&root->root_item);
+	ret = btrfs_find_free_objectid(trans, root, objectid, &objectid);
+	if (ret)
+		goto fail;
+
+	/*
+	 * copy blocks covered by extent #0 to new positions. extent #0 is
+	 * special, we can't rely on relocate_extents_range to relocate it.
+	 */
+	for (last_byte = 0; last_byte < first_free; last_byte += sectorsize) {
+		ret = custom_alloc_extent(root, sectorsize, 0, &key);
+		if (ret)
+			goto fail;
+		ret = copy_disk_extent(root, key.objectid, last_byte,
+				       sectorsize);
+		if (ret)
+			goto fail;
+		ret = record_file_extent(trans, root, objectid,
+					 &btrfs_inode, last_byte,
+					 key.objectid, sectorsize, 0);
+		if (ret)
+			goto fail;
+	}
+
+	while(1) {
+		key.objectid = last_byte;
+		key.offset = 0;
+		btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
+		ret = btrfs_search_slot(trans, fs_info->extent_root,
+					&key, &path, 0, 0);
+		if (ret < 0)
+			goto fail;
+next:
+		leaf = path.nodes[0];
+		if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(extent_root, &path);
+			if (ret < 0)
+				goto fail;
+			if (ret > 0)
+				break;
+			leaf = path.nodes[0];
+		}
+		btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+		if (last_byte > key.objectid ||
+		    key.type != BTRFS_EXTENT_ITEM_KEY) {
+			path.slots[0]++;
+			goto next;
+		}
+
+		bytenr = key.objectid;
+		num_bytes = key.offset;
+		ei = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_extent_item);
+		if (!(btrfs_extent_flags(leaf, ei) & BTRFS_EXTENT_FLAG_DATA)) {
+			path.slots[0]++;
+			goto next;
+		}
+
+		BUG_ON(btrfs_item_size_nr(leaf, path.slots[0]) != sizeof(*ei) +
+		       btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY));
+
+		iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+		key.type = btrfs_extent_inline_ref_type(leaf, iref);
+		BUG_ON(key.type != BTRFS_EXTENT_DATA_REF_KEY);
+		dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+		if (btrfs_extent_data_ref_root(leaf, dref) !=
+		    BTRFS_FS_TREE_OBJECTID) {
+			path.slots[0]++;
+			goto next;
+		}
+
+		if (bytenr > last_byte) {
+			ret = create_image_file_range(trans, root, objectid,
+						      &btrfs_inode, last_byte,
+						      bytenr, ext2_fs);
+			if (ret)
+				goto fail;
+		}
+		ret = record_file_extent(trans, root, objectid, &btrfs_inode,
+					 bytenr, bytenr, num_bytes, 0);
+		if (ret)
+			goto fail;
+		last_byte = bytenr + num_bytes;
+		btrfs_release_path(extent_root, &path);
+
+		if (trans->blocks_used >= 4096) {
+			ret = btrfs_commit_transaction(trans, root);
+			BUG_ON(ret);
+			trans = btrfs_start_transaction(root, 1);
+			BUG_ON(!trans);
+		}
+	}
+	btrfs_release_path(root, &path);
+	if (total_bytes > last_byte) {
+		ret = create_image_file_range(trans, root, objectid,
+					      &btrfs_inode, last_byte,
+					      total_bytes, ext2_fs);
+		if (ret)
+			goto fail;
+	}
+
+	ret = btrfs_insert_inode(trans, root, objectid, &btrfs_inode);
+	if (ret)
+		goto fail;
+
+	location.objectid = objectid;
+	location.offset = 0;
+	btrfs_set_key_type(&location, BTRFS_INODE_ITEM_KEY);
+	ret = btrfs_insert_dir_item(trans, root, name, strlen(name),
+				    btrfs_root_dirid(&root->root_item),
+				    &location, EXT2_FT_REG_FILE, objectid);
+	if (ret)
+		goto fail;
+	ret = btrfs_insert_inode_ref(trans, root, name, strlen(name),
+				     objectid,
+				     btrfs_root_dirid(&root->root_item),
+				     objectid);
+	if (ret)
+		goto fail;
+	location.objectid = btrfs_root_dirid(&root->root_item);
+	location.offset = 0;
+	btrfs_set_key_type(&location, BTRFS_INODE_ITEM_KEY);
+	ret = btrfs_lookup_inode(trans, root, &path, &location, 1);
+	if (ret)
+		goto fail;
+	leaf = path.nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_inode_item);
+	btrfs_set_inode_size(leaf, inode_item, strlen(name) * 2 +
+			     btrfs_inode_size(leaf, inode_item));
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_release_path(root, &path);
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+fail:
+	btrfs_release_path(root, &path);
+	return ret;
+}
+
+struct btrfs_root *link_subvol(struct btrfs_root *root, const char *base,
+			       u64 root_objectid)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_root *tree_root = fs_info->tree_root;
+	struct btrfs_root *new_root = NULL;
+	struct btrfs_path *path;
+	struct btrfs_inode_item *inode_item;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	u64 dirid = btrfs_root_dirid(&root->root_item);
+	u64 index = 2;
+	char buf[64];
+	int i;
+	int ret;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+
+	key.objectid = dirid;
+	key.type = BTRFS_DIR_INDEX_KEY;
+	key.offset = (u64)-1;
+
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+	BUG_ON(ret <= 0);
+
+	if (path->slots[0] > 0) {
+		path->slots[0]--;
+		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+		if (key.objectid == dirid && key.type == BTRFS_DIR_INDEX_KEY)
+			index = key.offset + 1;
+	}
+	btrfs_release_path(root, path);
+
+	trans = btrfs_start_transaction(root, 1);
+	BUG_ON(!trans);
+
+	key.objectid = dirid;
+	key.offset = 0;
+	key.type =  BTRFS_INODE_ITEM_KEY;
+
+	ret = btrfs_lookup_inode(trans, root, path, &key, 1);
+	BUG_ON(ret);
+	leaf = path->nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_inode_item);
+
+	key.objectid = root_objectid;
+	key.offset = (u64)-1;
+	key.type = BTRFS_ROOT_ITEM_KEY;
+
+	strcpy(buf, base);
+	for (i = 0; i < 1024; i++) {
+		ret = btrfs_insert_dir_item(trans, root, buf, strlen(buf),
+					    dirid, &key, BTRFS_FT_DIR, index);
+		if (ret != -EEXIST)
+			break;
+		sprintf(buf, "%s%d", base, i);
+	}
+	if (ret)
+		goto fail;
+
+	btrfs_set_inode_size(leaf, inode_item, strlen(buf) * 2 +
+			     btrfs_inode_size(leaf, inode_item));
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_release_path(root, path);
+
+	/* add the backref first */
+	ret = btrfs_add_root_ref(trans, tree_root, root_objectid,
+				 BTRFS_ROOT_BACKREF_KEY,
+				 root->root_key.objectid,
+				 dirid, index, buf, strlen(buf));
+	BUG_ON(ret);
+
+	/* now add the forward ref */
+	ret = btrfs_add_root_ref(trans, tree_root, root->root_key.objectid,
+				 BTRFS_ROOT_REF_KEY, root_objectid,
+				 dirid, index, buf, strlen(buf));
+
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+
+	new_root = btrfs_read_fs_root(fs_info, &key);
+	if (IS_ERR(new_root))
+		new_root = NULL;
+fail:
+	btrfs_free_path(path);
+	return new_root;
+}
+
+static int create_chunk_mapping(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root)
+{
+	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_root *chunk_root = info->chunk_root;
+	struct btrfs_root *extent_root = info->extent_root;
+	struct btrfs_device *device;
+	struct btrfs_block_group_cache *cache;
+	struct btrfs_dev_extent *extent;
+	struct extent_buffer *leaf;
+	struct btrfs_chunk chunk;
+	struct btrfs_key key;
+	struct btrfs_path path;
+	u64 cur_start;
+	u64 total_bytes;
+	u64 chunk_objectid;
+	int ret;
+
+	btrfs_init_path(&path);
+
+	total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+	chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+
+	BUG_ON(list_empty(&info->fs_devices->devices));
+	device = list_entry(info->fs_devices->devices.next,
+			    struct btrfs_device, dev_list);
+	BUG_ON(device->devid != info->fs_devices->latest_devid);
+
+	/* delete device extent created by make_btrfs */
+	key.objectid = device->devid;
+	key.offset = 0;
+	key.type = BTRFS_DEV_EXTENT_KEY;
+	ret = btrfs_search_slot(trans, device->dev_root, &key, &path, -1, 1);
+	if (ret < 0)
+		goto err;
+
+	BUG_ON(ret > 0);
+	ret = btrfs_del_item(trans, device->dev_root, &path);
+	if (ret)
+		goto err;
+	btrfs_release_path(device->dev_root, &path);
+
+	/* delete chunk item created by make_btrfs */
+	key.objectid = chunk_objectid;
+	key.offset = 0;
+	key.type = BTRFS_CHUNK_ITEM_KEY;
+	ret = btrfs_search_slot(trans, chunk_root, &key, &path, -1, 1);
+	if (ret < 0)
+		goto err;
+
+	BUG_ON(ret > 0);
+	ret = btrfs_del_item(trans, chunk_root, &path);
+	if (ret)
+		goto err;
+	btrfs_release_path(chunk_root, &path);
+
+	/* for each block group, create device extent and chunk item */
+	cur_start = 0;
+	while (cur_start < total_bytes) {
+		cache = btrfs_lookup_block_group(root->fs_info, cur_start);
+		BUG_ON(!cache);
+
+		/* insert device extent */
+		key.objectid = device->devid;
+		key.offset = cache->key.objectid;
+		key.type = BTRFS_DEV_EXTENT_KEY;
+		ret = btrfs_insert_empty_item(trans, device->dev_root, &path,
+					      &key, sizeof(*extent));
+		if (ret)
+			goto err;
+
+		leaf = path.nodes[0];
+		extent = btrfs_item_ptr(leaf, path.slots[0],
+					struct btrfs_dev_extent);
+
+		btrfs_set_dev_extent_chunk_tree(leaf, extent,
+						chunk_root->root_key.objectid);
+		btrfs_set_dev_extent_chunk_objectid(leaf, extent,
+						    chunk_objectid);
+		btrfs_set_dev_extent_chunk_offset(leaf, extent,
+						  cache->key.objectid);
+		btrfs_set_dev_extent_length(leaf, extent, cache->key.offset);
+		write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
+		    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
+		    BTRFS_UUID_SIZE);
+		btrfs_mark_buffer_dirty(leaf);
+		btrfs_release_path(device->dev_root, &path);
+
+		/* insert chunk item */
+		btrfs_set_stack_chunk_length(&chunk, cache->key.offset);
+		btrfs_set_stack_chunk_owner(&chunk,
+					    extent_root->root_key.objectid);
+		btrfs_set_stack_chunk_stripe_len(&chunk, STRIPE_LEN);
+		btrfs_set_stack_chunk_type(&chunk, cache->flags);
+		btrfs_set_stack_chunk_io_align(&chunk, device->io_align);
+		btrfs_set_stack_chunk_io_width(&chunk, device->io_width);
+		btrfs_set_stack_chunk_sector_size(&chunk, device->sector_size);
+		btrfs_set_stack_chunk_num_stripes(&chunk, 1);
+		btrfs_set_stack_chunk_sub_stripes(&chunk, 0);
+		btrfs_set_stack_stripe_devid(&chunk.stripe, device->devid);
+		btrfs_set_stack_stripe_offset(&chunk.stripe,
+					      cache->key.objectid);
+		memcpy(&chunk.stripe.dev_uuid, device->uuid, BTRFS_UUID_SIZE);
+
+		key.objectid = chunk_objectid;
+		key.offset = cache->key.objectid;
+		key.type = BTRFS_CHUNK_ITEM_KEY;
+
+		ret = btrfs_insert_item(trans, chunk_root, &key, &chunk,
+					btrfs_chunk_item_size(1));
+		if (ret)
+			goto err;
+
+		cur_start = cache->key.objectid + cache->key.offset;
+	}
+
+	device->bytes_used = total_bytes;
+	ret = btrfs_update_device(trans, device);
+err:
+	btrfs_release_path(device->dev_root, &path);
+	return ret;
+}
+
+static int create_subvol(struct btrfs_trans_handle *trans,
+			 struct btrfs_root *root, u64 root_objectid)
+{
+	struct extent_buffer *tmp;
+	struct btrfs_root *new_root;
+	struct btrfs_key key;
+	struct btrfs_root_item root_item;
+	int ret;
+
+	ret = btrfs_copy_root(trans, root, root->node, &tmp,
+			      root_objectid);
+	BUG_ON(ret);
+
+	memcpy(&root_item, &root->root_item, sizeof(root_item));
+	btrfs_set_root_bytenr(&root_item, tmp->start);
+	btrfs_set_root_level(&root_item, btrfs_header_level(tmp));
+	btrfs_set_root_generation(&root_item, trans->transid);
+	free_extent_buffer(tmp);
+
+	key.objectid = root_objectid;
+	key.type = BTRFS_ROOT_ITEM_KEY;
+	key.offset = trans->transid;
+	ret = btrfs_insert_root(trans, root->fs_info->tree_root,
+				&key, &root_item);
+
+	key.offset = (u64)-1;
+	new_root = btrfs_read_fs_root(root->fs_info, &key);
+	BUG_ON(!new_root || IS_ERR(new_root));
+
+	ret = btrfs_make_root_dir(trans, new_root, BTRFS_FIRST_FREE_OBJECTID);
+	BUG_ON(ret);
+
+	return 0;
+}
+
+static int init_btrfs(struct btrfs_root *root)
+{
+	int ret;
+	struct btrfs_key location;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct extent_buffer *tmp;
+
+	trans = btrfs_start_transaction(root, 1);
+	BUG_ON(!trans);
+	ret = btrfs_make_block_groups(trans, root);
+	if (ret)
+		goto err;
+	ret = btrfs_fix_block_accounting(trans, root);
+	if (ret)
+		goto err;
+	ret = create_chunk_mapping(trans, root);
+	if (ret)
+		goto err;
+	ret = btrfs_make_root_dir(trans, fs_info->tree_root,
+				  BTRFS_ROOT_TREE_DIR_OBJECTID);
+	if (ret)
+		goto err;
+	memcpy(&location, &root->root_key, sizeof(location));
+	location.offset = (u64)-1;
+	ret = btrfs_insert_dir_item(trans, fs_info->tree_root, "default", 7,
+				btrfs_super_root_dir(fs_info->super_copy),
+				&location, BTRFS_FT_DIR, 0);
+	if (ret)
+		goto err;
+	ret = btrfs_insert_inode_ref(trans, fs_info->tree_root, "default", 7,
+				location.objectid,
+				btrfs_super_root_dir(fs_info->super_copy), 0);
+	if (ret)
+		goto err;
+	btrfs_set_root_dirid(&fs_info->fs_root->root_item,
+			     BTRFS_FIRST_FREE_OBJECTID);
+
+	/* subvol for ext2 image file */
+	ret = create_subvol(trans, root, EXT2_IMAGE_SUBVOL_OBJECTID);
+	BUG_ON(ret);
+	/* subvol for data relocation */
+	ret = create_subvol(trans, root, BTRFS_DATA_RELOC_TREE_OBJECTID);
+	BUG_ON(ret);
+
+	ret = __btrfs_cow_block(trans, fs_info->csum_root,
+				fs_info->csum_root->node, NULL, 0, &tmp, 0, 0);
+	BUG_ON(ret);
+	free_extent_buffer(tmp);
+
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+err:
+	return ret;
+}
+
+/*
+ * Migrate super block to it's default position and zero 0 ~ 16k
+ */
+static int migrate_super_block(int fd, u64 old_bytenr, u32 sectorsize)
+{
+	int ret;
+	struct extent_buffer *buf;
+	struct btrfs_super_block *super;
+	u32 len;
+	u32 bytenr;
+
+	BUG_ON(sectorsize < sizeof(*super));
+	buf = malloc(sizeof(*buf) + sectorsize);
+	if (!buf)
+		return -ENOMEM;
+
+	buf->len = sectorsize;
+	ret = pread(fd, buf->data, sectorsize, old_bytenr);
+	if (ret != sectorsize)
+		goto fail;
+
+	super = (struct btrfs_super_block *)buf->data;
+	BUG_ON(btrfs_super_bytenr(super) != old_bytenr);
+	btrfs_set_super_bytenr(super, BTRFS_SUPER_INFO_OFFSET);
+
+	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
+	ret = pwrite(fd, buf->data, sectorsize, BTRFS_SUPER_INFO_OFFSET);
+	if (ret != sectorsize)
+		goto fail;
+
+	ret = fsync(fd);
+	if (ret)
+		goto fail;
+
+	memset(buf->data, 0, sectorsize);
+	for (bytenr = 0; bytenr < BTRFS_SUPER_INFO_OFFSET; ) {
+		len = BTRFS_SUPER_INFO_OFFSET - bytenr;
+		if (len > sectorsize)
+			len = sectorsize;
+		ret = pwrite(fd, buf->data, len, bytenr);
+		if (ret != len) {
+			fprintf(stderr, "unable to zero fill device\n");
+			break;
+		}
+		bytenr += len;
+	}
+	ret = 0;
+	fsync(fd);
+fail:
+	free(buf);
+	if (ret > 0)
+		ret = -1;
+	return ret;
+}
+
+static int prepare_system_chunk_sb(struct btrfs_super_block *super)
+{
+	struct btrfs_chunk *chunk;
+	struct btrfs_disk_key *key;
+	u32 sectorsize = btrfs_super_sectorsize(super);
+
+	key = (struct btrfs_disk_key *)(super->sys_chunk_array);
+	chunk = (struct btrfs_chunk *)(super->sys_chunk_array +
+				       sizeof(struct btrfs_disk_key));
+
+	btrfs_set_disk_key_objectid(key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+	btrfs_set_disk_key_type(key, BTRFS_CHUNK_ITEM_KEY);
+	btrfs_set_disk_key_offset(key, 0);
+
+	btrfs_set_stack_chunk_length(chunk, btrfs_super_total_bytes(super));
+	btrfs_set_stack_chunk_owner(chunk, BTRFS_EXTENT_TREE_OBJECTID);
+	btrfs_set_stack_chunk_stripe_len(chunk, 64 * 1024);
+	btrfs_set_stack_chunk_type(chunk, BTRFS_BLOCK_GROUP_SYSTEM);
+	btrfs_set_stack_chunk_io_align(chunk, sectorsize);
+	btrfs_set_stack_chunk_io_width(chunk, sectorsize);
+	btrfs_set_stack_chunk_sector_size(chunk, sectorsize);
+	btrfs_set_stack_chunk_num_stripes(chunk, 1);
+	btrfs_set_stack_chunk_sub_stripes(chunk, 0);
+	chunk->stripe.devid = super->dev_item.devid;
+	chunk->stripe.offset = cpu_to_le64(0);
+	memcpy(chunk->stripe.dev_uuid, super->dev_item.uuid, BTRFS_UUID_SIZE);
+	btrfs_set_super_sys_array_size(super, sizeof(*key) + sizeof(*chunk));
+	return 0;
+}
+
+static int prepare_system_chunk(int fd, u64 sb_bytenr, u32 sectorsize)
+{
+	int ret;
+	struct extent_buffer *buf;
+	struct btrfs_super_block *super;
+
+	BUG_ON(sectorsize < sizeof(*super));
+	buf = malloc(sizeof(*buf) + sectorsize);
+	if (!buf)
+		return -ENOMEM;
+
+	buf->len = sectorsize;
+	ret = pread(fd, buf->data, sectorsize, sb_bytenr);
+	if (ret != sectorsize)
+		goto fail;
+
+	super = (struct btrfs_super_block *)buf->data;
+	BUG_ON(btrfs_super_bytenr(super) != sb_bytenr);
+	BUG_ON(btrfs_super_num_devices(super) != 1);
+
+	ret = prepare_system_chunk_sb(super);
+	if (ret)
+		goto fail;
+
+	csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
+	ret = pwrite(fd, buf->data, sectorsize, sb_bytenr);
+	if (ret != sectorsize)
+		goto fail;
+
+	ret = 0;
+fail:
+	free(buf);
+	if (ret > 0)
+		ret = -1;
+	return ret;
+}
+
+static int relocate_one_reference(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  u64 extent_start, u64 extent_size,
+				  struct btrfs_key *extent_key,
+				  struct extent_io_tree *reloc_tree)
+{
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key key;
+	struct btrfs_path path;
+	struct btrfs_inode_item inode;
+	struct blk_iterate_data data;
+	u64 bytenr;
+	u64 num_bytes;
+	u64 cur_offset;
+	u64 new_pos;
+	u64 nbytes;
+	u64 sector_end;
+	u32 sectorsize = root->sectorsize;
+	unsigned long ptr;
+	int datacsum;
+	int fd;
+	int ret;
+
+	btrfs_init_path(&path);
+	ret = btrfs_search_slot(trans, root, extent_key, &path, -1, 1);
+	if (ret)
+		goto fail;
+
+	leaf = path.nodes[0];
+	fi = btrfs_item_ptr(leaf, path.slots[0],
+			    struct btrfs_file_extent_item);
+	BUG_ON(btrfs_file_extent_offset(leaf, fi) > 0);
+	if (extent_start != btrfs_file_extent_disk_bytenr(leaf, fi) ||
+	    extent_size != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
+		ret = 1;
+		goto fail;
+	}
+
+	bytenr = extent_start + btrfs_file_extent_offset(leaf, fi);
+	num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+
+	ret = btrfs_del_item(trans, root, &path);
+	if (ret)
+		goto fail;
+
+	ret = btrfs_free_extent(trans, root, extent_start, extent_size, 0,
+				root->root_key.objectid,
+				extent_key->objectid, extent_key->offset);
+	if (ret)
+		goto fail;
+
+	btrfs_release_path(root, &path);
+
+	key.objectid = extent_key->objectid;
+	key.offset = 0;
+	key.type =  BTRFS_INODE_ITEM_KEY;
+	ret = btrfs_lookup_inode(trans, root, &path, &key, 0);
+	if (ret)
+		goto fail;
+
+	leaf = path.nodes[0];
+	ptr = btrfs_item_ptr_offset(leaf, path.slots[0]);
+	read_extent_buffer(leaf, &inode, ptr, sizeof(inode));
+	btrfs_release_path(root, &path);
+
+	BUG_ON(num_bytes & (sectorsize - 1));
+	nbytes = btrfs_stack_inode_nbytes(&inode) - num_bytes;
+	btrfs_set_stack_inode_nbytes(&inode, nbytes);
+	datacsum = !(btrfs_stack_inode_flags(&inode) & BTRFS_INODE_NODATASUM);
+
+	data = (struct blk_iterate_data) {
+		.trans		= trans,
+		.root		= root,
+		.inode		= &inode,
+		.objectid	= extent_key->objectid,
+		.first_block	= extent_key->offset / sectorsize,
+		.disk_block	= 0,
+		.num_blocks	= 0,
+		.boundary	= (u64)-1,
+		.checksum	= datacsum,
+		.errcode	= 0,
+	};
+
+	cur_offset = extent_key->offset;
+	while (num_bytes > 0) {
+		sector_end = bytenr + sectorsize - 1;
+		if (test_range_bit(reloc_tree, bytenr, sector_end,
+				   EXTENT_LOCKED, 1)) {
+			ret = get_state_private(reloc_tree, bytenr, &new_pos);
+			BUG_ON(ret);
+		} else {
+			ret = custom_alloc_extent(root, sectorsize, 0, &key);
+			if (ret)
+				goto fail;
+			new_pos = key.objectid;
+
+			if (cur_offset == extent_key->offset) {
+				fd = root->fs_info->fs_devices->latest_bdev;
+				readahead(fd, bytenr, num_bytes);
+			}
+			ret = copy_disk_extent(root, new_pos, bytenr,
+					       sectorsize);
+			if (ret)
+				goto fail;
+			ret = set_extent_bits(reloc_tree, bytenr, sector_end,
+					      EXTENT_LOCKED, GFP_NOFS);
+			BUG_ON(ret);
+			ret = set_state_private(reloc_tree, bytenr, new_pos);
+			BUG_ON(ret);
+		}
+
+		ret = block_iterate_proc(NULL, new_pos / sectorsize,
+					 cur_offset / sectorsize, &data);
+		if (ret & BLOCK_ABORT) {
+			ret = data.errcode;
+			goto fail;
+		}
+
+		cur_offset += sectorsize;
+		bytenr += sectorsize;
+		num_bytes -= sectorsize;
+	}
+
+	if (data.num_blocks > 0) {
+		ret = record_file_blocks(trans, root,
+					 extent_key->objectid, &inode,
+					 data.first_block, data.disk_block,
+					 data.num_blocks, datacsum);
+		if (ret)
+			goto fail;
+	}
+
+	key.objectid = extent_key->objectid;
+	key.offset = 0;
+	key.type =  BTRFS_INODE_ITEM_KEY;
+	ret = btrfs_lookup_inode(trans, root, &path, &key, 1);
+	if (ret)
+		goto fail;
+
+	leaf = path.nodes[0];
+	ptr = btrfs_item_ptr_offset(leaf, path.slots[0]);
+	write_extent_buffer(leaf, &inode, ptr, sizeof(inode));
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_release_path(root, &path);
+
+fail:
+	btrfs_release_path(root, &path);
+	return ret;
+}
+
+static int relocate_extents_range(struct btrfs_root *fs_root,
+				  struct btrfs_root *ext2_root,
+				  u64 start_byte, u64 end_byte)
+{
+	struct btrfs_fs_info *info = fs_root->fs_info;
+	struct btrfs_root *extent_root = info->extent_root;
+	struct btrfs_root *cur_root = NULL;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_extent_data_ref *dref;
+	struct btrfs_extent_inline_ref *iref;
+	struct btrfs_extent_item *ei;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	struct btrfs_key extent_key;
+	struct btrfs_path path;
+	struct extent_io_tree reloc_tree;
+	unsigned long ptr;
+	unsigned long end;
+	u64 cur_byte;
+	u64 num_bytes;
+	u64 ref_root;
+	u64 num_extents;
+	int pass = 0;
+	int ret;
+
+	btrfs_init_path(&path);
+	extent_io_tree_init(&reloc_tree);
+
+	key.objectid = start_byte;
+	key.offset = 0;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
+	if (ret < 0)
+		goto fail;
+	if (ret > 0) {
+		ret = btrfs_previous_item(extent_root, &path, 0,
+					  BTRFS_EXTENT_ITEM_KEY);
+		if (ret < 0)
+			goto fail;
+		if (ret == 0) {
+			leaf = path.nodes[0];
+			btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+			if (key.objectid + key.offset > start_byte)
+				start_byte = key.objectid;
+		}
+	}
+	btrfs_release_path(extent_root, &path);
+again:
+	cur_root = (pass % 2 == 0) ? ext2_root : fs_root;
+	num_extents = 0;
+
+	trans = btrfs_start_transaction(cur_root, 1);
+	BUG_ON(!trans);
+
+	cur_byte = start_byte;
+	while (1) {
+		key.objectid = cur_byte;
+		key.offset = 0;
+		key.type = BTRFS_EXTENT_ITEM_KEY;
+		ret = btrfs_search_slot(trans, extent_root,
+					&key, &path, 0, 0);
+		if (ret < 0)
+			goto fail;
+next:
+		leaf = path.nodes[0];
+		if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(extent_root, &path);
+			if (ret < 0)
+				goto fail;
+			if (ret > 0)
+				break;
+			leaf = path.nodes[0];
+		}
+
+		btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+		if (key.objectid < cur_byte ||
+		    key.type != BTRFS_EXTENT_ITEM_KEY) {
+			path.slots[0]++;
+			goto next;
+		}
+		if (key.objectid >= end_byte)
+			break;
+
+		num_extents++;
+
+		cur_byte = key.objectid;
+		num_bytes = key.offset;
+		ei = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_extent_item);
+		BUG_ON(!(btrfs_extent_flags(leaf, ei) &
+			 BTRFS_EXTENT_FLAG_DATA));
+
+		ptr = btrfs_item_ptr_offset(leaf, path.slots[0]);
+		end = ptr + btrfs_item_size_nr(leaf, path.slots[0]);
+
+		ptr += sizeof(struct btrfs_extent_item);
+
+		while (ptr < end) {
+			iref = (struct btrfs_extent_inline_ref *)ptr;
+			key.type = btrfs_extent_inline_ref_type(leaf, iref);
+			BUG_ON(key.type != BTRFS_EXTENT_DATA_REF_KEY);
+			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+			ref_root = btrfs_extent_data_ref_root(leaf, dref);
+			extent_key.objectid =
+				btrfs_extent_data_ref_objectid(leaf, dref);
+			extent_key.offset =
+				btrfs_extent_data_ref_offset(leaf, dref);
+			extent_key.type = BTRFS_EXTENT_DATA_KEY;
+			BUG_ON(btrfs_extent_data_ref_count(leaf, dref) != 1);
+
+			if (ref_root == cur_root->root_key.objectid)
+				break;
+
+			ptr += btrfs_extent_inline_ref_size(key.type);
+		}
+
+		if (ptr >= end) {
+			path.slots[0]++;
+			goto next;
+		}
+
+		ret = relocate_one_reference(trans, cur_root, cur_byte,
+					     num_bytes, &extent_key,
+					     &reloc_tree);
+		if (ret < 0)
+			goto fail;
+
+		cur_byte += num_bytes;
+		btrfs_release_path(extent_root, &path);
+
+		if (trans->blocks_used >= 4096) {
+			ret = btrfs_commit_transaction(trans, cur_root);
+			BUG_ON(ret);
+			trans = btrfs_start_transaction(cur_root, 1);
+			BUG_ON(!trans);
+		}
+	}
+	btrfs_release_path(cur_root, &path);
+
+	ret = btrfs_commit_transaction(trans, cur_root);
+	BUG_ON(ret);
+
+	if (num_extents > 0 && pass++ < 16)
+		goto again;
+
+	ret = (num_extents > 0) ? -1 : 0;
+fail:
+	btrfs_release_path(cur_root, &path);
+	extent_io_tree_cleanup(&reloc_tree);
+	return ret;
+}
+
+/*
+ * relocate data in system chunk
+ */
+static int cleanup_sys_chunk(struct btrfs_root *fs_root,
+			     struct btrfs_root *ext2_root)
+{
+	struct btrfs_block_group_cache *cache;
+	int i, ret = 0;
+	u64 offset = 0;
+	u64 end_byte;
+
+	while(1) {
+		cache = btrfs_lookup_block_group(fs_root->fs_info, offset);
+		if (!cache)
+			break;
+
+		end_byte = cache->key.objectid + cache->key.offset;
+		if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
+			ret = relocate_extents_range(fs_root, ext2_root,
+						     cache->key.objectid,
+						     end_byte);
+			if (ret)
+				goto fail;
+		}
+		offset = end_byte;
+	}
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		offset = btrfs_sb_offset(i);
+		offset &= ~((u64)STRIPE_LEN - 1);
+
+		ret = relocate_extents_range(fs_root, ext2_root,
+					     offset, offset + STRIPE_LEN);
+		if (ret)
+			goto fail;
+	}
+	ret = 0;
+fail:
+	return ret;
+}
+
+static int fixup_chunk_mapping(struct btrfs_root *root)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_root *chunk_root = info->chunk_root;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	struct btrfs_path path;
+	struct btrfs_chunk chunk;
+	unsigned long ptr;
+	u32 size;
+	u64 type;
+	int ret;
+
+	btrfs_init_path(&path);
+
+	trans = btrfs_start_transaction(root, 1);
+	BUG_ON(!trans);
+
+	/*
+	 * recow the whole chunk tree. this will move all chunk tree blocks
+	 * into system block group.
+	 */
+	memset(&key, 0, sizeof(key));
+	while (1) {
+		ret = btrfs_search_slot(trans, chunk_root, &key, &path, 0, 1);
+		if (ret < 0)
+			goto err;
+
+		ret = btrfs_next_leaf(chunk_root, &path);
+		if (ret < 0)
+			goto err;
+		if (ret > 0)
+			break;
+
+		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+		btrfs_release_path(chunk_root, &path);
+	}
+	btrfs_release_path(chunk_root, &path);
+
+	/* fixup the system chunk array in super block */
+	btrfs_set_super_sys_array_size(info->super_copy, 0);
+
+	key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+	key.offset = 0;
+	key.type = BTRFS_CHUNK_ITEM_KEY;
+
+	ret = btrfs_search_slot(trans, chunk_root, &key, &path, 0, 0);
+	if (ret < 0)
+		goto err;
+	BUG_ON(ret != 0);
+	while(1) {
+		leaf = path.nodes[0];
+		if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(chunk_root, &path);
+			if (ret < 0)
+				goto err;
+			if (ret > 0)
+				break;
+			leaf = path.nodes[0];
+		}
+		btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+		if (key.type != BTRFS_CHUNK_ITEM_KEY)
+			goto next;
+
+		ptr = btrfs_item_ptr_offset(leaf, path.slots[0]);
+		size = btrfs_item_size_nr(leaf, path.slots[0]);
+		BUG_ON(size != sizeof(chunk));
+		read_extent_buffer(leaf, &chunk, ptr, size);
+		type = btrfs_stack_chunk_type(&chunk);
+
+		if (!(type & BTRFS_BLOCK_GROUP_SYSTEM))
+			goto next;
+
+		ret = btrfs_add_system_chunk(trans, chunk_root, &key,
+					     &chunk, size);
+		if (ret)
+			goto err;
+next:
+		path.slots[0]++;
+	}
+
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+err:
+	btrfs_release_path(chunk_root, &path);
+	return ret;
+}
+
+int do_convert(const char *devname, int datacsum, int packing, int noxattr)
+{
+	int i, ret;
+	int fd = -1;
+	u32 blocksize;
+	u64 blocks[7];
+	u64 total_bytes;
+	u64 super_bytenr;
+	ext2_filsys ext2_fs;
+	struct btrfs_root *root;
+	struct btrfs_root *ext2_root;
+
+	ret = open_ext2fs(devname, &ext2_fs);
+	if (ret) {
+		fprintf(stderr, "unable to open the Ext2fs\n");
+		goto fail;
+	}
+	blocksize = ext2_fs->blocksize;
+	total_bytes = (u64)ext2_fs->super->s_blocks_count * blocksize;
+	if (blocksize < 4096) {
+		fprintf(stderr, "block size is too small\n");
+		goto fail;
+	}
+	if (!(ext2_fs->super->s_feature_incompat &
+	      EXT2_FEATURE_INCOMPAT_FILETYPE)) {
+		fprintf(stderr, "filetype feature is missing\n");
+		goto fail;
+	}
+	for (i = 0; i < 7; i++) {
+		ret = ext2_alloc_block(ext2_fs, 0, blocks + i);
+		if (ret) {
+			fprintf(stderr, "not enough free space\n");
+			goto fail;
+		}
+		blocks[i] *= blocksize;
+	}
+	super_bytenr = blocks[0];
+	fd = open(devname, O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "unable to open %s\n", devname);
+		goto fail;
+	}
+	ret = make_btrfs(fd, devname, ext2_fs->super->s_volume_name,
+			 blocks, total_bytes, blocksize, blocksize,
+			 blocksize, blocksize);
+	if (ret) {
+		fprintf(stderr, "unable to create initial ctree\n");
+		goto fail;
+	}
+	/* create a system chunk that maps the whole device */
+	ret = prepare_system_chunk(fd, super_bytenr, blocksize);
+	if (ret) {
+		fprintf(stderr, "unable to update system chunk\n");
+		goto fail;
+	}
+	root = open_ctree_fd(fd, devname, super_bytenr, O_RDWR);
+	if (!root) {
+		fprintf(stderr, "unable to open ctree\n");
+		goto fail;
+	}
+	ret = cache_free_extents(root, ext2_fs);
+	if (ret) {
+		fprintf(stderr, "error during cache_free_extents %d\n", ret);
+		goto fail;
+	}
+	root->fs_info->extent_ops = &extent_ops;
+	/* recover block allocation bitmap */
+	for (i = 0; i < 7; i++) {
+		blocks[i] /= blocksize;
+		ext2_free_block(ext2_fs, blocks[i]);
+	}
+	ret = init_btrfs(root);
+	if (ret) {
+		fprintf(stderr, "unable to setup the root tree\n");
+		goto fail;
+	}
+	printf("creating btrfs metadata.\n");
+	ret = copy_inodes(root, ext2_fs, datacsum, packing, noxattr);
+	if (ret) {
+		fprintf(stderr, "error during copy_inodes %d\n", ret);
+		goto fail;
+	}
+	printf("creating ext2fs image file.\n");
+	ext2_root = link_subvol(root, "ext2_saved", EXT2_IMAGE_SUBVOL_OBJECTID);
+	if (!ext2_root) {
+		fprintf(stderr, "unable to create subvol\n");
+		goto fail;
+	}
+	ret = create_ext2_image(ext2_root, ext2_fs, "image");
+	if (ret) {
+		fprintf(stderr, "error during create_ext2_image %d\n", ret);
+		goto fail;
+	}
+	printf("cleaning up system chunk.\n");
+	ret = cleanup_sys_chunk(root, ext2_root);
+	if (ret) {
+		fprintf(stderr, "error during cleanup_sys_chunk %d\n", ret);
+		goto fail;
+	}
+	ret = close_ctree(root);
+	if (ret) {
+		fprintf(stderr, "error during close_ctree %d\n", ret);
+		goto fail;
+	}
+	close_ext2fs(ext2_fs);
+
+	/*
+	 * If this step succeed, we get a mountable btrfs. Otherwise
+	 * the ext2fs is left unchanged.
+	 */
+	ret = migrate_super_block(fd, super_bytenr, blocksize);
+	if (ret) {
+		fprintf(stderr, "unable to migrate super block\n");
+		goto fail;
+	}
+
+	root = open_ctree_fd(fd, devname, 0, O_RDWR);
+	if (!root) {
+		fprintf(stderr, "unable to open ctree\n");
+		goto fail;
+	}
+	/* move chunk tree into system chunk. */
+	ret = fixup_chunk_mapping(root);
+	if (ret) {
+		fprintf(stderr, "error during fixup_chunk_tree\n");
+		goto fail;
+	}
+	ret = close_ctree(root);
+	close(fd);
+
+	printf("conversion complete.\n");
+	return 0;
+fail:
+	if (fd != -1)
+		close(fd);
+	fprintf(stderr, "conversion aborted.\n");
+	return -1;
+}
+
+static int may_rollback(struct btrfs_root *root)
+{
+	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_multi_bio *multi = NULL;
+	u64 bytenr;
+	u64 length;
+	u64 physical;
+	u64 total_bytes;
+	int num_stripes;
+	int ret;
+
+	if (btrfs_super_num_devices(info->super_copy) != 1)
+		goto fail;
+
+	bytenr = BTRFS_SUPER_INFO_OFFSET;
+	total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+
+	while (1) {
+		ret = btrfs_map_block(&info->mapping_tree, WRITE, bytenr,
+				      &length, &multi, 0, NULL);
+		if (ret)
+			goto fail;
+
+		num_stripes = multi->num_stripes;
+		physical = multi->stripes[0].physical;
+		kfree(multi);
+
+		if (num_stripes != 1 || physical != bytenr)
+			goto fail;
+
+		bytenr += length;
+		if (bytenr >= total_bytes)
+			break;
+	}
+	return 0;
+fail:
+	return -1;
+}
+
+int do_rollback(const char *devname, int force)
+{
+	int fd = -1;
+	int ret;
+	int i;
+	struct btrfs_root *root;
+	struct btrfs_root *ext2_root;
+	struct btrfs_root *chunk_root;
+	struct btrfs_dir_item *dir;
+	struct btrfs_inode_item *inode;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_trans_handle *trans;
+	struct extent_buffer *leaf;
+	struct btrfs_block_group_cache *cache1;
+	struct btrfs_block_group_cache *cache2;
+	struct btrfs_key key;
+	struct btrfs_path path;
+	struct extent_io_tree io_tree;
+	char *buf = NULL;
+	char *name;
+	u64 bytenr;
+	u64 num_bytes;
+	u64 root_dir;
+	u64 objectid;
+	u64 offset;
+	u64 start;
+	u64 end;
+	u64 sb_bytenr;
+	u64 first_free;
+	u64 total_bytes;
+	u32 sectorsize;
+
+	extent_io_tree_init(&io_tree);
+
+	fd = open(devname, O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "unable to open %s\n", devname);
+		goto fail;
+	}
+	root = open_ctree_fd(fd, devname, 0, O_RDWR);
+	if (!root) {
+		fprintf(stderr, "unable to open ctree\n");
+		goto fail;
+	}
+	ret = may_rollback(root);
+	if (ret < 0) {
+		fprintf(stderr, "unable to do rollback\n");
+		goto fail;
+	}
+
+	sectorsize = root->sectorsize;
+	buf = malloc(sectorsize);
+	if (!buf) {
+		fprintf(stderr, "unable to allocate memory\n");
+		goto fail;
+	}
+
+	btrfs_init_path(&path);
+
+	key.objectid = EXT2_IMAGE_SUBVOL_OBJECTID;
+	key.type = BTRFS_ROOT_ITEM_KEY;
+	key.offset = (u64)-1;
+	ext2_root = btrfs_read_fs_root(root->fs_info, &key);
+	if (!ext2_root || IS_ERR(ext2_root)) {
+		fprintf(stderr, "unable to open subvol %llu\n",
+			key.objectid);
+		goto fail;
+	}
+
+	name = "image";
+	root_dir = btrfs_root_dirid(&root->root_item);
+	dir = btrfs_lookup_dir_item(NULL, ext2_root, &path,
+				   root_dir, name, strlen(name), 0);
+	if (!dir || IS_ERR(dir)) {
+		fprintf(stderr, "unable to find file %s\n", name);
+		goto fail;
+	}
+	leaf = path.nodes[0];
+	btrfs_dir_item_key_to_cpu(leaf, dir, &key);
+	btrfs_release_path(ext2_root, &path);
+
+	objectid = key.objectid;
+
+	ret = btrfs_lookup_inode(NULL, ext2_root, &path, &key, 0);
+	if (ret) {
+		fprintf(stderr, "unable to find inode item\n");
+		goto fail;
+	}
+	leaf = path.nodes[0];
+	inode = btrfs_item_ptr(leaf, path.slots[0], struct btrfs_inode_item);
+	total_bytes = btrfs_inode_size(leaf, inode);
+	btrfs_release_path(ext2_root, &path);
+
+	key.objectid = objectid;
+	key.offset = 0;
+	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+	ret = btrfs_search_slot(NULL, ext2_root, &key, &path, 0, 0);
+	if (ret != 0) {
+		fprintf(stderr, "unable to find first file extent\n");
+		btrfs_release_path(ext2_root, &path);
+		goto fail;
+	}
+
+	/* build mapping tree for the relocated blocks */
+	for (offset = 0; offset < total_bytes; ) {
+		leaf = path.nodes[0];
+		if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(root, &path);
+			if (ret != 0)
+				break;	
+			continue;
+		}
+
+		btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
+		if (key.objectid != objectid || key.offset != offset ||
+		    btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
+			break;
+
+		fi = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_file_extent_item);
+		if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
+			break;
+		if (btrfs_file_extent_compression(leaf, fi) ||
+		    btrfs_file_extent_encryption(leaf, fi) ||
+		    btrfs_file_extent_other_encoding(leaf, fi))
+			break;
+
+		bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+		/* skip holes and direct mapped extents */
+		if (bytenr == 0 || bytenr == offset)
+			goto next_extent;
+
+		bytenr += btrfs_file_extent_offset(leaf, fi);
+		num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
+
+		cache1 = btrfs_lookup_block_group(root->fs_info, offset);
+		cache2 =  btrfs_lookup_block_group(root->fs_info,
+						   offset + num_bytes - 1);
+		if (!cache1 || cache1 != cache2 ||
+		    (!(cache1->flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
+		     !intersect_with_sb(offset, num_bytes)))
+			break;
+
+		set_extent_bits(&io_tree, offset, offset + num_bytes - 1,
+				EXTENT_LOCKED, GFP_NOFS);
+		set_state_private(&io_tree, offset, bytenr);
+next_extent:
+		offset += btrfs_file_extent_num_bytes(leaf, fi);
+		path.slots[0]++;
+	}
+	btrfs_release_path(ext2_root, &path);
+
+	if (offset < total_bytes) {
+		fprintf(stderr, "unable to build extent mapping\n");
+		goto fail;
+	}
+
+	first_free = BTRFS_SUPER_INFO_OFFSET + 2 * sectorsize - 1;
+	first_free &= ~((u64)sectorsize - 1);
+	/* backup for extent #0 should exist */
+	if(!test_range_bit(&io_tree, 0, first_free - 1, EXTENT_LOCKED, 1)) {
+		fprintf(stderr, "no backup for the first extent\n");
+		goto fail;
+	}
+	/* force no allocation from system block group */
+	root->fs_info->system_allocs = -1;
+	trans = btrfs_start_transaction(root, 1);
+	BUG_ON(!trans);
+	/*
+	 * recow the whole chunk tree, this will remove all chunk tree blocks
+	 * from system block group
+	 */
+	chunk_root = root->fs_info->chunk_root;
+	memset(&key, 0, sizeof(key));
+	while (1) {
+		ret = btrfs_search_slot(trans, chunk_root, &key, &path, 0, 1);
+		if (ret < 0)
+			break;
+
+		ret = btrfs_next_leaf(chunk_root, &path);
+		if (ret)
+			break;
+
+		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+		btrfs_release_path(chunk_root, &path);
+	}
+	btrfs_release_path(chunk_root, &path);
+
+	offset = 0;
+	num_bytes = 0;
+	while(1) {
+		cache1 = btrfs_lookup_block_group(root->fs_info, offset);
+		if (!cache1)
+			break;
+
+		if (cache1->flags & BTRFS_BLOCK_GROUP_SYSTEM)
+			num_bytes += btrfs_block_group_used(&cache1->item);
+
+		offset = cache1->key.objectid + cache1->key.offset;
+	}
+	/* only extent #0 left in system block group? */
+	if (num_bytes > first_free) {
+		fprintf(stderr, "unable to empty system block group\n");
+		goto fail;
+	}
+	/* create a system chunk that maps the whole device */
+	ret = prepare_system_chunk_sb(root->fs_info->super_copy);
+	if (ret) {
+		fprintf(stderr, "unable to update system chunk\n");
+		goto fail;
+	}
+
+	ret = btrfs_commit_transaction(trans, root);
+	BUG_ON(ret);
+
+	ret = close_ctree(root);
+	if (ret) {
+		fprintf(stderr, "error during close_ctree %d\n", ret);
+		goto fail;
+	}
+
+	/* zero btrfs super block mirrors */
+	memset(buf, 0, sectorsize);
+	for (i = 1 ; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		if (bytenr >= total_bytes)
+			break;
+		ret = pwrite(fd, buf, sectorsize, bytenr);
+	}
+
+	sb_bytenr = (u64)-1;
+	/* copy all relocated blocks back */
+	while(1) {
+		ret = find_first_extent_bit(&io_tree, 0, &start, &end,
+					    EXTENT_LOCKED);
+		if (ret)
+			break;
+
+		ret = get_state_private(&io_tree, start, &bytenr);
+		BUG_ON(ret);
+
+		clear_extent_bits(&io_tree, start, end, EXTENT_LOCKED,
+				  GFP_NOFS);
+
+		while (start <= end) {
+			if (start == BTRFS_SUPER_INFO_OFFSET) {
+				sb_bytenr = bytenr;
+				goto next_sector;
+			}
+			ret = pread(fd, buf, sectorsize, bytenr);
+			if (ret < 0) {
+				fprintf(stderr, "error during pread %d\n", ret);
+				goto fail;
+			}
+			BUG_ON(ret != sectorsize);
+			ret = pwrite(fd, buf, sectorsize, start);
+			if (ret < 0) {
+				fprintf(stderr, "error during pwrite %d\n", ret);
+				goto fail;
+			}
+			BUG_ON(ret != sectorsize);
+next_sector:
+			start += sectorsize;
+			bytenr += sectorsize;
+		}
+	}
+
+	ret = fsync(fd);
+	if (ret) {
+		fprintf(stderr, "error during fsync %d\n", ret);
+		goto fail;
+	}
+	/*
+	 * finally, overwrite btrfs super block.
+	 */
+	ret = pread(fd, buf, sectorsize, sb_bytenr);
+	if (ret < 0) {
+		fprintf(stderr, "error during pread %d\n", ret);
+		goto fail;
+	}
+	BUG_ON(ret != sectorsize);
+	ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
+	if (ret < 0) {
+		fprintf(stderr, "error during pwrite %d\n", ret);
+		goto fail;
+	}
+	BUG_ON(ret != sectorsize);
+	ret = fsync(fd);
+	if (ret) {
+		fprintf(stderr, "error during fsync %d\n", ret);
+		goto fail;
+	}
+
+	close(fd);
+	free(buf);
+	extent_io_tree_cleanup(&io_tree);
+	printf("rollback complete.\n");
+	return 0;
+
+fail:
+	if (fd != -1)
+		close(fd);
+	free(buf);
+	fprintf(stderr, "rollback aborted.\n");
+	return -1;
+}
+
+static void print_usage(void)
+{
+	printf("usage: btrfs-convert [-d] [-i] [-n] [-r] device\n");
+	printf("\t-d disable data checksum\n");
+	printf("\t-i ignore xattrs and ACLs\n");
+	printf("\t-n disable packing of small files\n");
+	printf("\t-r roll back to ext2fs\n");
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+	int packing = 1;
+	int noxattr = 0;
+	int datacsum = 1;
+	int rollback = 0;
+	char *file;
+	while(1) {
+		int c = getopt(argc, argv, "dinr");
+		if (c < 0)
+			break;
+		switch(c) {
+			case 'd':
+				datacsum = 0;
+				break;
+			case 'i':
+				noxattr = 1;
+				break;
+			case 'n':
+				packing = 0;
+				break;
+			case 'r':
+				rollback = 1;
+				break;
+			default:
+				print_usage();
+				return 1;
+		}
+	}
+	argc = argc - optind;
+	if (argc != 1) {
+		print_usage();
+		return 1;
+	}
+
+	file = argv[optind];
+	if (check_mounted(file)) {
+		fprintf(stderr, "%s is mounted\n", file);
+		return 1;
+	}
+
+	if (rollback) {
+		ret = do_rollback(file, 0);
+	} else {
+		ret = do_convert(file, datacsum, packing, noxattr);
+	}
+	if (ret)
+		return 1;
+	return 0;
+}