New upstream release.

1 files changed, 510 insertions, 1759 deletions

diff --git a/convert/main.c b/convert/main.c
index 8d9f29fa..0deccd9c 100644
--- a/convert/main.c
+++ b/convert/main.c
@@ -16,69 +16,116 @@
  * Boston, MA 021110-1307, USA.
  */
 
+/*
+ * Btrfs convert design:
+ *
+ * The overall design of btrfs convert is like the following:
+ *
+ * |<------------------Old fs----------------------------->|
+ * |<- used ->| |<- used ->|                    |<- used ->|
+ *                           ||
+ *                           \/
+ * |<---------------Btrfs fs------------------------------>|
+ * |<-   Old data chunk  ->|< new chunk (D/M/S)>|<- ODC  ->|
+ * |<-Old-FE->| |<-Old-FE->|<- Btrfs extents  ->|<-Old-FE->|
+ *
+ * ODC    = Old data chunk, btrfs chunks containing old fs data
+ *          Mapped 1:1 (logical address == device offset)
+ * Old-FE = file extents pointing to old fs.
+ *
+ * So old fs used space is (mostly) kept as is, while btrfs will insert
+ * its chunk (Data/Meta/Sys) into large enough free space.
+ * In this way, we can create different profiles for metadata/data for
+ * converted fs.
+ *
+ * We must reserve and relocate 3 ranges for btrfs:
+ * * [0, 1M)                    - area never used for any data except the first
+ *                                superblock
+ * * [btrfs_sb_offset(1), +64K) - 1st superblock backup copy
+ * * [btrfs_sb_offset(2), +64K) - 2nd, dtto
+ *
+ * Most work is spent handling corner cases around these reserved ranges.
+ *
+ * Detailed workflow is:
+ * 1)   Scan old fs used space and calculate data chunk layout
+ * 1.1) Scan old fs
+ *      We can a map used space of old fs
+ *
+ * 1.2) Calculate data chunk layout - this is the hard part
+ *      New data chunks must meet 3 conditions using result fomr 1.1
+ *      a. Large enough to be a chunk
+ *      b. Doesn't intersect reserved ranges
+ *      c. Covers all the remaining old fs used space
+ *
+ *      NOTE: This can be simplified if we don't need to handle backup supers
+ *
+ * 1.3) Calculate usable space for new btrfs chunks
+ *      Btrfs chunk usable space must meet 3 conditions using result from 1.2
+ *      a. Large enough to be a chunk
+ *      b. Doesn't intersect reserved ranges
+ *      c. Doesn't cover any data chunks in 1.1
+ *
+ * 2)   Create basic btrfs filesystem structure
+ *      Initial metadata and sys chunks are inserted in the first availabe
+ *      space found in step 1.3
+ *      Then insert all data chunks into the basic btrfs
+ *
+ * 3)   Create convert image
+ *      We need to relocate reserved ranges here.
+ *      After this step, the convert image is done, and we can use the image
+ *      as reflink source to create old files
+ *
+ * 4)   Iterate old fs to create files
+ *      We just reflink file extents from old fs to newly created files on
+ *      btrfs.
+ */
+
 #include "kerncompat.h"
 
-#include <sys/ioctl.h>
-#include <sys/mount.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <uuid/uuid.h>
-#include <linux/limits.h>
 #include <getopt.h>
+#include <pthread.h>
+#include <stdbool.h>
 
 #include "ctree.h"
 #include "disk-io.h"
 #include "volumes.h"
 #include "transaction.h"
-#include "crc32c.h"
 #include "utils.h"
 #include "task-utils.h"
+#include "help.h"
+#include "mkfs/common.h"
+#include "convert/common.h"
+#include "convert/source-fs.h"
+#include "fsfeatures.h"
 
-#if BTRFSCONVERT_EXT2
-#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)
-
-/*
- * Compatibility code for e2fsprogs 1.41 which doesn't support RO compat flag
- * BIGALLOC.
- * Unlike normal RO compat flag, BIGALLOC affects how e2fsprogs check used
- * space, and btrfs-convert heavily relies on it.
- */
-#ifdef HAVE_OLD_E2FSPROGS
-#define EXT2FS_CLUSTER_RATIO(fs)	(1)
-#define EXT2_CLUSTERS_PER_GROUP(s)	(EXT2_BLOCKS_PER_GROUP(s))
-#define EXT2FS_B2C(fs, blk)		(blk)
-#endif
+const struct btrfs_convert_operations ext2_convert_ops;
 
+static const struct btrfs_convert_operations *convert_operations[] = {
+#if BTRFSCONVERT_EXT2
+	&ext2_convert_ops,
 #endif
-
-#define CONV_IMAGE_SUBVOL_OBJECTID BTRFS_FIRST_FREE_OBJECTID
-
-struct task_ctx {
-	uint32_t max_copy_inodes;
-	uint32_t cur_copy_inodes;
-	struct task_info *info;
 };
 
 static void *print_copied_inodes(void *p)
 {
 	struct task_ctx *priv = p;
 	const char work_indicator[] = { '.', 'o', 'O', 'o' };
-	uint32_t count = 0;
+	u64 count = 0;
 
 	task_period_start(priv->info, 1000 /* 1s */);
 	while (1) {
 		count++;
-		printf("copy inodes [%c] [%10d/%10d]\r",
-		       work_indicator[count % 4], priv->cur_copy_inodes,
-		       priv->max_copy_inodes);
+		pthread_mutex_lock(&priv->mutex);
+		printf("copy inodes [%c] [%10llu/%10llu]\r",
+		       work_indicator[count % 4],
+		       (unsigned long long)priv->cur_copy_inodes,
+		       (unsigned long long)priv->max_copy_inodes);
+		pthread_mutex_unlock(&priv->mutex);
 		fflush(stdout);
 		task_period_wait(priv->info);
 	}
@@ -94,38 +141,11 @@ static int after_copied_inodes(void *p)
 	return 0;
 }
 
-struct btrfs_convert_context;
-struct btrfs_convert_operations {
-	const char *name;
-	int (*open_fs)(struct btrfs_convert_context *cctx, const char *devname);
-	int (*read_used_space)(struct btrfs_convert_context *cctx);
-	int (*copy_inodes)(struct btrfs_convert_context *cctx,
-			 struct btrfs_root *root, int datacsum,
-			 int packing, int noxattr, struct task_ctx *p);
-	void (*close_fs)(struct btrfs_convert_context *cctx);
-	int (*check_state)(struct btrfs_convert_context *cctx);
-};
-
-static void init_convert_context(struct btrfs_convert_context *cctx)
-{
-	cache_tree_init(&cctx->used);
-	cache_tree_init(&cctx->data_chunks);
-	cache_tree_init(&cctx->free);
-}
-
-static void clean_convert_context(struct btrfs_convert_context *cctx)
-{
-	free_extent_cache_tree(&cctx->used);
-	free_extent_cache_tree(&cctx->data_chunks);
-	free_extent_cache_tree(&cctx->free);
-}
-
 static inline int copy_inodes(struct btrfs_convert_context *cctx,
-			      struct btrfs_root *root, int datacsum,
-			      int packing, int noxattr, struct task_ctx *p)
+			      struct btrfs_root *root, u32 convert_flags,
+			      struct task_ctx *p)
 {
-	return cctx->convert_ops->copy_inodes(cctx, root, datacsum, packing,
-					     noxattr, p);
+	return cctx->convert_ops->copy_inodes(cctx, root, convert_flags, p);
 }
 
 static inline void convert_close_fs(struct btrfs_convert_context *cctx)
@@ -138,72 +158,11 @@ static inline int convert_check_state(struct btrfs_convert_context *cctx)
 	return cctx->convert_ops->check_state(cctx);
 }
 
-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)BTRFS_STRIPE_LEN - 1);
-
-		if (bytenr < offset + BTRFS_STRIPE_LEN &&
-		    bytenr + num_bytes > offset)
-			return 1;
-	}
-	return 0;
-}
-
-static int convert_insert_dirent(struct btrfs_trans_handle *trans,
-				 struct btrfs_root *root,
-				 const char *name, size_t name_len,
-				 u64 dir, u64 objectid,
-				 u8 file_type, u64 index_cnt,
-				 struct btrfs_inode_item *inode)
-{
-	int ret;
-	u64 inode_size;
-	struct btrfs_key location = {
-		.objectid = objectid,
-		.offset = 0,
-		.type = BTRFS_INODE_ITEM_KEY,
-	};
-
-	ret = btrfs_insert_dir_item(trans, root, name, name_len,
-				    dir, &location, file_type, index_cnt);
-	if (ret)
-		return ret;
-	ret = btrfs_insert_inode_ref(trans, root, name, name_len,
-				     objectid, dir, index_cnt);
-	if (ret)
-		return ret;
-	inode_size = btrfs_stack_inode_size(inode) + name_len * 2;
-	btrfs_set_stack_inode_size(inode, inode_size);
-
-	return 0;
-}
-
-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;
-}
-
 static int csum_disk_extent(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root,
 			    u64 disk_bytenr, u64 num_bytes)
 {
-	u32 blocksize = root->sectorsize;
+	u32 blocksize = root->fs_info->sectorsize;
 	u64 offset;
 	char *buffer;
 	int ret = 0;
@@ -228,198 +187,12 @@ static int csum_disk_extent(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-struct blk_iterate_data {
-	struct btrfs_trans_handle *trans;
-	struct btrfs_root *root;
-	struct btrfs_root *convert_root;
-	struct btrfs_inode_item *inode;
-	u64 convert_ino;
-	u64 objectid;
-	u64 first_block;
-	u64 disk_block;
-	u64 num_blocks;
-	u64 boundary;
-	int checksum;
-	int errcode;
-};
-
-static void init_blk_iterate_data(struct blk_iterate_data *data,
-				  struct btrfs_trans_handle *trans,
-				  struct btrfs_root *root,
-				  struct btrfs_inode_item *inode,
-				  u64 objectid, int checksum)
-{
-	struct btrfs_key key;
-
-	data->trans		= trans;
-	data->root		= root;
-	data->inode		= inode;
-	data->objectid		= objectid;
-	data->first_block	= 0;
-	data->disk_block	= 0;
-	data->num_blocks	= 0;
-	data->boundary		= (u64)-1;
-	data->checksum		= checksum;
-	data->errcode		= 0;
-
-	key.objectid = CONV_IMAGE_SUBVOL_OBJECTID;
-	key.type = BTRFS_ROOT_ITEM_KEY;
-	key.offset = (u64)-1;
-	data->convert_root = btrfs_read_fs_root(root->fs_info, &key);
-	/* Impossible as we just opened it before */
-	BUG_ON(!data->convert_root || IS_ERR(data->convert_root));
-	data->convert_ino = BTRFS_FIRST_FREE_OBJECTID + 1;
-}
-
-/*
- * Record a file extent in original filesystem into btrfs one.
- * The special point is, old disk_block can point to a reserved range.
- * So here, we don't use disk_block directly but search convert_root
- * to get the real disk_bytenr.
- */
-static int record_file_blocks(struct blk_iterate_data *data,
-			      u64 file_block, u64 disk_block, u64 num_blocks)
-{
-	int ret = 0;
-	struct btrfs_root *root = data->root;
-	struct btrfs_root *convert_root = data->convert_root;
-	struct btrfs_path path;
-	u64 file_pos = file_block * root->sectorsize;
-	u64 old_disk_bytenr = disk_block * root->sectorsize;
-	u64 num_bytes = num_blocks * root->sectorsize;
-	u64 cur_off = old_disk_bytenr;
-
-	/* Hole, pass it to record_file_extent directly */
-	if (old_disk_bytenr == 0)
-		return btrfs_record_file_extent(data->trans, root,
-				data->objectid, data->inode, file_pos, 0,
-				num_bytes);
-
-	btrfs_init_path(&path);
-
-	/*
-	 * Search real disk bytenr from convert root
-	 */
-	while (cur_off < old_disk_bytenr + num_bytes) {
-		struct btrfs_key key;
-		struct btrfs_file_extent_item *fi;
-		struct extent_buffer *node;
-		int slot;
-		u64 extent_disk_bytenr;
-		u64 extent_num_bytes;
-		u64 real_disk_bytenr;
-		u64 cur_len;
-
-		key.objectid = data->convert_ino;
-		key.type = BTRFS_EXTENT_DATA_KEY;
-		key.offset = cur_off;
-
-		ret = btrfs_search_slot(NULL, convert_root, &key, &path, 0, 0);
-		if (ret < 0)
-			break;
-		if (ret > 0) {
-			ret = btrfs_previous_item(convert_root, &path,
-						  data->convert_ino,
-						  BTRFS_EXTENT_DATA_KEY);
-			if (ret < 0)
-				break;
-			if (ret > 0) {
-				ret = -ENOENT;
-				break;
-			}
-		}
-		node = path.nodes[0];
-		slot = path.slots[0];
-		btrfs_item_key_to_cpu(node, &key, slot);
-		BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY ||
-		       key.objectid != data->convert_ino ||
-		       key.offset > cur_off);
-		fi = btrfs_item_ptr(node, slot, struct btrfs_file_extent_item);
-		extent_disk_bytenr = btrfs_file_extent_disk_bytenr(node, fi);
-		extent_num_bytes = btrfs_file_extent_num_bytes(node, fi);
-		BUG_ON(cur_off - key.offset >= extent_num_bytes);
-		btrfs_release_path(&path);
-
-		if (extent_disk_bytenr)
-			real_disk_bytenr = cur_off - key.offset +
-					   extent_disk_bytenr;
-		else
-			real_disk_bytenr = 0;
-		cur_len = min(key.offset + extent_num_bytes,
-			      old_disk_bytenr + num_bytes) - cur_off;
-		ret = btrfs_record_file_extent(data->trans, data->root,
-					data->objectid, data->inode, file_pos,
-					real_disk_bytenr, cur_len);
-		if (ret < 0)
-			break;
-		cur_off += cur_len;
-		file_pos += cur_len;
-
-		/*
-		 * No need to care about csum
-		 * As every byte of old fs image is calculated for csum, no
-		 * need to waste CPU cycles now.
-		 */
-	}
-	btrfs_release_path(&path);
-	return ret;
-}
-
-static int block_iterate_proc(u64 disk_block, u64 file_block,
-		              struct blk_iterate_data *idata)
-{
-	int ret = 0;
-	int sb_region;
-	int do_barrier;
-	struct btrfs_root *root = idata->root;
-	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(idata, idata->first_block,
-						 idata->disk_block,
-						 idata->num_blocks);
-			if (ret)
-				goto fail;
-			idata->first_block += idata->num_blocks;
-			idata->num_blocks = 0;
-		}
-		if (file_block > idata->first_block) {
-			ret = record_file_blocks(idata, idata->first_block,
-					0, file_block - idata->first_block);
-			if (ret)
-				goto fail;
-		}
-
-		if (sb_region) {
-			bytenr += BTRFS_STRIPE_LEN - 1;
-			bytenr &= ~((u64)BTRFS_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++;
-fail:
-	return ret;
-}
-
 static int create_image_file_range(struct btrfs_trans_handle *trans,
 				      struct btrfs_root *root,
 				      struct cache_tree *used,
 				      struct btrfs_inode_item *inode,
 				      u64 ino, u64 bytenr, u64 *ret_len,
-				      int datacsum)
+				      u32 convert_flags)
 {
 	struct cache_extent *cache;
 	struct btrfs_block_group_cache *bg_cache;
@@ -427,13 +200,14 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 	u64 disk_bytenr;
 	int i;
 	int ret;
+	u32 datacsum = convert_flags & CONVERT_FLAG_DATACSUM;
 
-	if (bytenr != round_down(bytenr, root->sectorsize)) {
+	if (bytenr != round_down(bytenr, root->fs_info->sectorsize)) {
 		error("bytenr not sectorsize aligned: %llu",
 				(unsigned long long)bytenr);
 		return -EINVAL;
 	}
-	if (len != round_down(len, root->sectorsize)) {
+	if (len != round_down(len, root->fs_info->sectorsize)) {
 		error("length not sectorsize aligned: %llu",
 				(unsigned long long)len);
 		return -EINVAL;
@@ -441,47 +215,40 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 	len = min_t(u64, len, BTRFS_MAX_EXTENT_SIZE);
 
 	/*
-	 * Skip sb ranges first
-	 * [0, 1M), [sb_offset(1), +64K), [sb_offset(2), +64K].
+	 * Skip reserved ranges first
 	 *
 	 * Or we will insert a hole into current image file, and later
 	 * migrate block will fail as there is already a file extent.
 	 */
-	if (bytenr < 1024 * 1024) {
-		*ret_len = 1024 * 1024 - bytenr;
-		return 0;
-	}
-	for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
-		u64 cur = btrfs_sb_offset(i);
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *reserved = &btrfs_reserved_ranges[i];
 
-		if (bytenr >= cur && bytenr < cur + BTRFS_STRIPE_LEN) {
-			*ret_len = cur + BTRFS_STRIPE_LEN - bytenr;
+		/*
+		 * |-- reserved --|
+		 *         |--range---|
+		 * or
+		 * |---- reserved ----|
+		 *    |-- range --|
+		 * Skip to reserved range end
+		 */
+		if (bytenr >= reserved->start && bytenr < range_end(reserved)) {
+			*ret_len = range_end(reserved) - bytenr;
 			return 0;
 		}
-	}
-	for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
-		u64 cur = btrfs_sb_offset(i);
 
 		/*
-		 *      |--reserved--|
+		 *      |---reserved---|
 		 * |----range-------|
-		 * May still need to go through file extent inserts
+		 * Leading part may still create a file extent
 		 */
-		if (bytenr < cur && bytenr + len >= cur) {
-			len = min_t(u64, len, cur - bytenr);
+		if (bytenr < reserved->start &&
+		    bytenr + len >= range_end(reserved)) {
+			len = min_t(u64, len, reserved->start - bytenr);
 			break;
 		}
-		/*
-		 * |--reserved--|
-		 *      |---range---|
-		 * Drop out, no need to insert anything
-		 */
-		if (bytenr >= cur && bytenr < cur + BTRFS_STRIPE_LEN) {
-			*ret_len = cur + BTRFS_STRIPE_LEN - bytenr;
-			return 0;
-		}
 	}
 
+	/* Check if we are going to insert regular file extent, or hole */
 	cache = search_cache_extent(used, bytenr);
 	if (cache) {
 		if (cache->start <= bytenr) {
@@ -489,6 +256,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 			 * |///////Used///////|
 			 *	|<--insert--->|
 			 *	bytenr
+			 * Insert one real file extent
 			 */
 			len = min_t(u64, len, cache->start + cache->size -
 				    bytenr);
@@ -498,6 +266,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 			 *		|//Used//|
 			 *  |<-insert-->|
 			 *  bytenr
+			 *  Insert one hole
 			 */
 			len = min(len, cache->start - bytenr);
 			disk_bytenr = 0;
@@ -508,6 +277,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 		 * |//Used//|		|EOF
 		 *	    |<-insert-->|
 		 *	    bytenr
+		 * Insert one hole
 		 */
 		disk_bytenr = 0;
 		datacsum = 0;
@@ -526,7 +296,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
 			    bg_cache->key.offset - bytenr);
 	}
 
-	if (len != round_down(len, root->sectorsize)) {
+	if (len != round_down(len, root->fs_info->sectorsize)) {
 		error("remaining length not sectorsize aligned: %llu",
 				(unsigned long long)len);
 		return -EINVAL;
@@ -553,25 +323,33 @@ static int migrate_one_reserved_range(struct btrfs_trans_handle *trans,
 				      struct btrfs_root *root,
 				      struct cache_tree *used,
 				      struct btrfs_inode_item *inode, int fd,
-				      u64 ino, u64 start, u64 len, int datacsum)
+				      u64 ino, const struct simple_range *range,
+				      u32 convert_flags)
 {
-	u64 cur_off = start;
-	u64 cur_len = len;
-	u64 hole_start = start;
+	u64 cur_off = range->start;
+	u64 cur_len = range->len;
+	u64 hole_start = range->start;
 	u64 hole_len;
 	struct cache_extent *cache;
 	struct btrfs_key key;
 	struct extent_buffer *eb;
 	int ret = 0;
 
-	while (cur_off < start + len) {
+	/*
+	 * It's possible that there are holes in reserved range:
+	 * |<---------------- Reserved range ---------------------->|
+	 *      |<- Old fs data ->|   |<- Old fs data ->|
+	 * So here we need to iterate through old fs used space and only
+	 * migrate ranges that covered by old fs data.
+	 */
+	while (cur_off < range_end(range)) {
 		cache = lookup_cache_extent(used, cur_off, cur_len);
 		if (!cache)
 			break;
 		cur_off = max(cache->start, cur_off);
-		cur_len = min(cache->start + cache->size, start + len) -
+		cur_len = min(cache->start + cache->size, range_end(range)) -
 			  cur_off;
-		BUG_ON(cur_len < root->sectorsize);
+		BUG_ON(cur_len < root->fs_info->sectorsize);
 
 		/* reserve extent for the data */
 		ret = btrfs_reserve_extent(trans, root, cur_len, 0, 0, (u64)-1,
@@ -595,7 +373,7 @@ static int migrate_one_reserved_range(struct btrfs_trans_handle *trans,
 		eb->len = key.offset;
 
 		/* Write the data */
-		ret = write_and_map_eb(trans, root, eb);
+		ret = write_and_map_eb(root->fs_info, eb);
 		free(eb);
 		if (ret < 0)
 			break;
@@ -606,7 +384,7 @@ static int migrate_one_reserved_range(struct btrfs_trans_handle *trans,
 		if (ret < 0)
 			break;
 		/* Finally, insert csum items */
-		if (datacsum)
+		if (convert_flags & CONVERT_FLAG_DATACSUM)
 			ret = csum_disk_extent(trans, root, key.objectid,
 					       key.offset);
 
@@ -621,56 +399,43 @@ static int migrate_one_reserved_range(struct btrfs_trans_handle *trans,
 
 		cur_off += key.offset;
 		hole_start = cur_off;
-		cur_len = start + len - cur_off;
+		cur_len = range_end(range) - cur_off;
 	}
-	/* Last hole */
-	if (start + len - hole_start > 0)
+	/*
+	 * Last hole
+	 * |<---- reserved -------->|
+	 * |<- Old fs data ->|      |
+	 *                   | Hole |
+	 */
+	if (range_end(range) - hole_start > 0)
 		ret = btrfs_record_file_extent(trans, root, ino, inode,
-				hole_start, 0, start + len - hole_start);
+				hole_start, 0, range_end(range) - hole_start);
 	return ret;
 }
 
 /*
  * Relocate the used ext2 data in reserved ranges
- * [0,1M)
- * [btrfs_sb_offset(1), +BTRFS_STRIPE_LEN)
- * [btrfs_sb_offset(2), +BTRFS_STRIPE_LEN)
  */
 static int migrate_reserved_ranges(struct btrfs_trans_handle *trans,
 				   struct btrfs_root *root,
 				   struct cache_tree *used,
 				   struct btrfs_inode_item *inode, int fd,
-				   u64 ino, u64 total_bytes, int datacsum)
+				   u64 ino, u64 total_bytes, u32 convert_flags)
 {
-	u64 cur_off;
-	u64 cur_len;
+	int i;
 	int ret = 0;
 
-	/* 0 ~ 1M */
-	cur_off = 0;
-	cur_len = 1024 * 1024;
-	ret = migrate_one_reserved_range(trans, root, used, inode, fd, ino,
-					 cur_off, cur_len, datacsum);
-	if (ret < 0)
-		return ret;
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
 
-	/* second sb(fisrt sb is included in 0~1M) */
-	cur_off = btrfs_sb_offset(1);
-	cur_len = min(total_bytes, cur_off + BTRFS_STRIPE_LEN) - cur_off;
-	if (cur_off > total_bytes)
-		return ret;
-	ret = migrate_one_reserved_range(trans, root, used, inode, fd, ino,
-					 cur_off, cur_len, datacsum);
-	if (ret < 0)
-		return ret;
+		if (range->start > total_bytes)
+			return ret;
+		ret = migrate_one_reserved_range(trans, root, used, inode, fd,
+						 ino, range, convert_flags);
+		if (ret < 0)
+			return ret;
+	}
 
-	/* Last sb */
-	cur_off = btrfs_sb_offset(2);
-	cur_len = min(total_bytes, cur_off + BTRFS_STRIPE_LEN) - cur_off;
-	if (cur_off > total_bytes)
-		return ret;
-	ret = migrate_one_reserved_range(trans, root, used, inode, fd, ino,
-					 cur_off, cur_len, datacsum);
 	return ret;
 }
 
@@ -843,26 +608,25 @@ static int wipe_one_reserved_range(struct cache_tree *tree,
 static int wipe_reserved_ranges(struct cache_tree *tree, u64 min_stripe_size,
 				int ensure_size)
 {
+	int i;
 	int ret;
 
-	ret = wipe_one_reserved_range(tree, 0, 1024 * 1024, min_stripe_size,
-				      ensure_size);
-	if (ret < 0)
-		return ret;
-	ret = wipe_one_reserved_range(tree, btrfs_sb_offset(1),
-			BTRFS_STRIPE_LEN, min_stripe_size, ensure_size);
-	if (ret < 0)
-		return ret;
-	ret = wipe_one_reserved_range(tree, btrfs_sb_offset(2),
-			BTRFS_STRIPE_LEN, min_stripe_size, ensure_size);
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
+
+		ret = wipe_one_reserved_range(tree, range->start, range->len,
+					      min_stripe_size, ensure_size);
+		if (ret < 0)
+			return ret;
+	}
 	return ret;
 }
 
 static int calculate_available_space(struct btrfs_convert_context *cctx)
 {
-	struct cache_tree *used = &cctx->used;
+	struct cache_tree *used = &cctx->used_space;
 	struct cache_tree *data_chunks = &cctx->data_chunks;
-	struct cache_tree *free = &cctx->free;
+	struct cache_tree *free = &cctx->free_space;
 	struct cache_extent *cache;
 	u64 cur_off = 0;
 	/*
@@ -964,7 +728,7 @@ static int convert_read_used_space(struct btrfs_convert_context *cctx)
 static int create_image(struct btrfs_root *root,
 			   struct btrfs_mkfs_config *cfg,
 			   struct btrfs_convert_context *cctx, int fd,
-			   u64 size, char *name, int datacsum)
+			   u64 size, char *name, u32 convert_flags)
 {
 	struct btrfs_inode_item buf;
 	struct btrfs_trans_handle *trans;
@@ -977,7 +741,7 @@ static int create_image(struct btrfs_root *root,
 	u64 flags = BTRFS_INODE_READONLY;
 	int ret;
 
-	if (!datacsum)
+	if (!(convert_flags & CONVERT_FLAG_DATACSUM))
 		flags |= BTRFS_INODE_NODATASUM;
 
 	trans = btrfs_start_transaction(root, 1);
@@ -1020,7 +784,7 @@ static int create_image(struct btrfs_root *root,
 	 * Create a new used space cache, which doesn't contain the reserved
 	 * range
 	 */
-	for (cache = first_cache_extent(&cctx->used); cache;
+	for (cache = first_cache_extent(&cctx->used_space); cache;
 	     cache = next_cache_extent(cache)) {
 		ret = add_cache_extent(&used_tmp, cache->start, cache->size);
 		if (ret < 0)
@@ -1039,15 +803,15 @@ static int create_image(struct btrfs_root *root,
 		u64 len = size - cur;
 
 		ret = create_image_file_range(trans, root, &used_tmp,
-						&buf, ino, cur, &len, datacsum);
+						&buf, ino, cur, &len,
+						convert_flags);
 		if (ret < 0)
 			goto out;
 		cur += len;
 	}
 	/* Handle the reserved ranges */
-	ret = migrate_reserved_ranges(trans, root, &cctx->used, &buf, fd, ino,
-				      cfg->num_bytes, datacsum);
-
+	ret = migrate_reserved_ranges(trans, root, &cctx->used_space, &buf, fd,
+			ino, cfg->num_bytes, convert_flags);
 
 	key.objectid = ino;
 	key.type = BTRFS_INODE_ITEM_KEY;
@@ -1250,7 +1014,8 @@ static int make_convert_data_block_groups(struct btrfs_trans_handle *trans,
 	 */
 	max_chunk_size = cfg->num_bytes / 10;
 	max_chunk_size = min((u64)(1024 * 1024 * 1024), max_chunk_size);
-	max_chunk_size = round_down(max_chunk_size, extent_root->sectorsize);
+	max_chunk_size = round_down(max_chunk_size,
+				    extent_root->fs_info->sectorsize);
 
 	for (cache = first_cache_extent(data_chunks); cache;
 	     cache = next_cache_extent(cache)) {
@@ -1262,12 +1027,12 @@ static int make_convert_data_block_groups(struct btrfs_trans_handle *trans,
 
 			len = min(max_chunk_size,
 				  cache->start + cache->size - cur);
-			ret = btrfs_alloc_data_chunk(trans, extent_root,
+			ret = btrfs_alloc_data_chunk(trans, fs_info,
 					&cur_backup, len,
 					BTRFS_BLOCK_GROUP_DATA, 1);
 			if (ret < 0)
 				break;
-			ret = btrfs_make_block_group(trans, extent_root, 0,
+			ret = btrfs_make_block_group(trans, fs_info, 0,
 					BTRFS_BLOCK_GROUP_DATA,
 					BTRFS_FIRST_CHUNK_TREE_OBJECTID,
 					cur, len);
@@ -1291,8 +1056,7 @@ static int make_convert_data_block_groups(struct btrfs_trans_handle *trans,
  * But the convert image subvolume is *NOT* linked to fs tree yet.
  */
 static int init_btrfs(struct btrfs_mkfs_config *cfg, struct btrfs_root *root,
-			 struct btrfs_convert_context *cctx, int datacsum,
-			 int packing, int noxattr)
+			 struct btrfs_convert_context *cctx, u32 convert_flags)
 {
 	struct btrfs_key location;
 	struct btrfs_trans_handle *trans;
@@ -1412,951 +1176,11 @@ fail:
 	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, BTRFS_STRIPE_LEN);
-	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;
-	btrfs_set_stack_stripe_offset(&chunk->stripe, 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;
-}
-
-#if BTRFSCONVERT_EXT2
-
-/*
- * Open Ext2fs in readonly mode, read block allocation bitmap and
- * inode bitmap into memory.
- */
-static int ext2_open_fs(struct btrfs_convert_context *cctx, const char *name)
-{
-	errcode_t ret;
-	ext2_filsys ext2_fs;
-	ext2_ino_t ino;
-	u32 ro_feature;
-
-	ret = ext2fs_open(name, 0, 0, 0, unix_io_manager, &ext2_fs);
-	if (ret) {
-		fprintf(stderr, "ext2fs_open: %s\n", error_message(ret));
-		return -1;
-	}
-	/*
-	 * We need to know exactly the used space, some RO compat flags like
-	 * BIGALLOC will affect how used space is present.
-	 * So we need manuall check any unsupported RO compat flags
-	 */
-	ro_feature = ext2_fs->super->s_feature_ro_compat;
-	if (ro_feature & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
-		error(
-"unsupported RO features detected: %x, abort convert to avoid possible corruption",
-		      ro_feature & ~EXT2_LIB_FEATURE_COMPAT_SUPP);
-		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);
-	}
-
-	if (!(ext2_fs->super->s_feature_incompat &
-	      EXT2_FEATURE_INCOMPAT_FILETYPE)) {
-		error("filetype feature is missing");
-		goto fail;
-	}
-
-	cctx->fs_data = ext2_fs;
-	cctx->blocksize = ext2_fs->blocksize;
-	cctx->block_count = ext2_fs->super->s_blocks_count;
-	cctx->total_bytes = ext2_fs->blocksize * ext2_fs->super->s_blocks_count;
-	cctx->volume_name = strndup(ext2_fs->super->s_volume_name, 16);
-	cctx->first_data_block = ext2_fs->super->s_first_data_block;
-	cctx->inodes_count = ext2_fs->super->s_inodes_count;
-	cctx->free_inodes_count = ext2_fs->super->s_free_inodes_count;
-	return 0;
-fail:
-	ext2fs_close(ext2_fs);
-	return -1;
-}
-
-static int __ext2_add_one_block(ext2_filsys fs, char *bitmap,
-				unsigned long group_nr, struct cache_tree *used)
-{
-	unsigned long offset;
-	unsigned i;
-	int ret = 0;
-
-	offset = fs->super->s_first_data_block;
-	offset /= EXT2FS_CLUSTER_RATIO(fs);
-	offset += group_nr * EXT2_CLUSTERS_PER_GROUP(fs->super);
-	for (i = 0; i < EXT2_CLUSTERS_PER_GROUP(fs->super); i++) {
-		if ((i + offset) >= ext2fs_blocks_count(fs->super))
-			break;
-
-		if (ext2fs_test_bit(i, bitmap)) {
-			u64 start;
-
-			start = (i + offset) * EXT2FS_CLUSTER_RATIO(fs);
-			start *= fs->blocksize;
-			ret = add_merge_cache_extent(used, start,
-						     fs->blocksize);
-			if (ret < 0)
-				break;
-		}
-	}
-	return ret;
-}
-
-/*
- * Read all used ext2 space into cctx->used cache tree
- */
-static int ext2_read_used_space(struct btrfs_convert_context *cctx)
-{
-	ext2_filsys fs = (ext2_filsys)cctx->fs_data;
-	blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
-	struct cache_tree *used_tree = &cctx->used;
-	char *block_bitmap = NULL;
-	unsigned long i;
-	int block_nbytes;
-	int ret = 0;
-
-	block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
-	/* Shouldn't happen */
-	BUG_ON(!fs->block_map);
-
-	block_bitmap = malloc(block_nbytes);
-	if (!block_bitmap)
-		return -ENOMEM;
-
-	for (i = 0; i < fs->group_desc_count; i++) {
-		ret = ext2fs_get_block_bitmap_range(fs->block_map, blk_itr,
-						block_nbytes * 8, block_bitmap);
-		if (ret) {
-			error("fail to get bitmap from ext2, %s",
-			      strerror(-ret));
-			break;
-		}
-		ret = __ext2_add_one_block(fs, block_bitmap, i, used_tree);
-		if (ret < 0) {
-			error("fail to build used space tree, %s",
-			      strerror(-ret));
-			break;
-		}
-		blk_itr += EXT2_CLUSTERS_PER_GROUP(fs->super);
-	}
-
-	free(block_bitmap);
-	return ret;
-}
-
-static void ext2_close_fs(struct btrfs_convert_context *cctx)
-{
-	if (cctx->volume_name) {
-		free(cctx->volume_name);
-		cctx->volume_name = NULL;
-	}
-	ext2fs_close(cctx->fs_data);
-}
-
-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 ext2_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 ext2_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;
-	char dotdot[] = "..";
-	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;
-
-	file_type = dirent->name_len >> 8;
-	BUG_ON(file_type > EXT2_FT_SYMLINK);
-
-	ret = convert_insert_dirent(idata->trans, idata->root, dirent->name,
-				    name_len, idata->objectid, objectid,
-				    ext2_filetype_conversion_table[file_type],
-				    idata->index_cnt, idata->inode);
-	if (ret < 0) {
-		idata->errcode = ret;
-		return BLOCK_ABORT;
-	}
-
-	idata->index_cnt++;
-	return 0;
-}
-
-static int ext2_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,
-				  ext2_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 ext2_block_iterate_proc(ext2_filsys fs, blk_t *blocknr,
-			        e2_blkcnt_t blockcnt, blk_t ref_block,
-			        int ref_offset, void *priv_data)
-{
-	int ret;
-	struct blk_iterate_data *idata;
-	idata = (struct blk_iterate_data *)priv_data;
-	ret = block_iterate_proc(*blocknr, blockcnt, idata);
-	if (ret) {
-		idata->errcode = ret;
-		return BLOCK_ABORT;
-	}
-	return 0;
-}
-
-/*
- * traverse file's data blocks, record these data blocks as file extents.
- */
-static int ext2_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;
-
-	init_blk_iterate_data(&data, trans, root, btrfs_inode, objectid,
-			      datacsum);
-
-	err = ext2fs_block_iterate2(ext2_fs, ext2_ino, BLOCK_FLAG_DATA_ONLY,
-				    NULL, ext2_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(&data, data.first_block,
-					 data.disk_block, data.num_blocks);
-		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(&data, data.first_block, 0,
-					 last_block - data.first_block);
-	}
-fail:
-	free(buffer);
-	return ret;
-error:
-	fprintf(stderr, "ext2fs_block_iterate2: %s\n", error_message(err));
-	return -1;
-}
-
-static int ext2_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 = ext2_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
-
-/* 23.2.5 acl_tag_t values */
-
-#define ACL_UNDEFINED_TAG       (0x00)
-#define ACL_USER_OBJ            (0x01)
-#define ACL_USER                (0x02)
-#define ACL_GROUP_OBJ           (0x04)
-#define ACL_GROUP               (0x08)
-#define ACL_MASK                (0x10)
-#define ACL_OTHER               (0x20)
-
-/* 23.2.7 ACL qualifier constants */
-
-#define ACL_UNDEFINED_ID        ((id_t)-1)
-
-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 ext2_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:
-	free(databuf);
-	return ret;
-}
-
-static int ext2_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 = ext2_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 = ext2_copy_single_xattr(trans, root, objectid,
-					entry, data, datalen);
-		if (ret)
-			goto out;
-		entry = EXT2_EXT_ATTR_NEXT(entry);
-	}
-out:
-	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 void ext2_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_sequence(dst, 0);
-	btrfs_set_stack_inode_transid(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]));
-		}
-	}
-	memset(&dst->reserved, 0, sizeof(dst->reserved));
-}
-static int ext2_check_state(struct btrfs_convert_context *cctx)
-{
-	ext2_filsys fs = cctx->fs_data;
-
-        if (!(fs->super->s_state & EXT2_VALID_FS))
-		return 1;
-	else if (fs->super->s_state & EXT2_ERROR_FS)
-		return 1;
-	else
-		return 0;
-}
-
-/* EXT2_*_FL to BTRFS_INODE_FLAG_* stringification helper */
-#define COPY_ONE_EXT2_FLAG(flags, ext2_inode, name) ({			\
-	if (ext2_inode->i_flags & EXT2_##name##_FL)			\
-		flags |= BTRFS_INODE_##name;				\
-})
-
-/*
- * Convert EXT2_*_FL to corresponding BTRFS_INODE_* flags
- *
- * Only a subset of EXT_*_FL is supported in btrfs.
- */
-static void ext2_convert_inode_flags(struct btrfs_inode_item *dst,
-				     struct ext2_inode *src)
-{
-	u64 flags = 0;
-
-	COPY_ONE_EXT2_FLAG(flags, src, APPEND);
-	COPY_ONE_EXT2_FLAG(flags, src, SYNC);
-	COPY_ONE_EXT2_FLAG(flags, src, IMMUTABLE);
-	COPY_ONE_EXT2_FLAG(flags, src, NODUMP);
-	COPY_ONE_EXT2_FLAG(flags, src, NOATIME);
-	COPY_ONE_EXT2_FLAG(flags, src, DIRSYNC);
-	btrfs_set_stack_inode_flags(dst, flags);
-}
-
-/*
- * copy a single inode. do all the required works, such as cloning
- * inode item, creating file extents and creating directory entries.
- */
-static int ext2_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_inode_item btrfs_inode;
-
-	if (ext2_inode->i_links_count == 0)
-		return 0;
-
-	ext2_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);
-	}
-	ext2_convert_inode_flags(&btrfs_inode, ext2_inode);
-
-	switch (ext2_inode->i_mode & S_IFMT) {
-	case S_IFREG:
-		ret = ext2_create_file_extents(trans, root, objectid,
-			&btrfs_inode, ext2_fs, ext2_ino, datacsum, packing);
-		break;
-	case S_IFDIR:
-		ret = ext2_create_dir_entries(trans, root, objectid,
-				&btrfs_inode, ext2_fs, ext2_ino);
-		break;
-	case S_IFLNK:
-		ret = ext2_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 = ext2_copy_extended_attrs(trans, root, objectid,
-				&btrfs_inode, ext2_fs, ext2_ino);
-		if (ret)
-			return ret;
-	}
-	return btrfs_insert_inode(trans, root, objectid, &btrfs_inode);
-}
-
-/*
- * scan ext2's inode bitmap and copy all used inodes.
- */
-static int ext2_copy_inodes(struct btrfs_convert_context *cctx,
-			    struct btrfs_root *root,
-			    int datacsum, int packing, int noxattr, struct task_ctx *p)
-{
-	ext2_filsys ext2_fs = cctx->fs_data;
-	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 = ext2_copy_single_inode(trans, root,
-					objectid, ext2_fs, ext2_ino,
-					&ext2_inode, datacsum, packing,
-					noxattr);
-		p->cur_copy_inodes++;
-		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);
-	ext2fs_close_inode_scan(ext2_scan);
-
-	return ret;
-}
-
-static const struct btrfs_convert_operations ext2_convert_ops = {
-	.name			= "ext2",
-	.open_fs		= ext2_open_fs,
-	.read_used_space	= ext2_read_used_space,
-	.copy_inodes		= ext2_copy_inodes,
-	.close_fs		= ext2_close_fs,
-	.check_state		= ext2_check_state,
-};
-
-#endif
-
-static const struct btrfs_convert_operations *convert_operations[] = {
-#if BTRFSCONVERT_EXT2
-	&ext2_convert_ops,
-#endif
-};
-
 static int convert_open_fs(const char *devname,
 			   struct btrfs_convert_context *cctx)
 {
 	int i;
 
-	memset(cctx, 0, sizeof(*cctx));
-
 	for (i = 0; i < ARRAY_SIZE(convert_operations); i++) {
 		int ret = convert_operations[i]->open_fs(cctx, devname);
 
@@ -2370,9 +1194,8 @@ static int convert_open_fs(const char *devname,
 	return -1;
 }
 
-static int do_convert(const char *devname, int datacsum, int packing,
-		int noxattr, u32 nodesize, int copylabel, const char *fslabel,
-		int progress, u64 features)
+static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
+		const char *fslabel, int progress, u64 features)
 {
 	int ret;
 	int fd = -1;
@@ -2382,7 +1205,7 @@ static int do_convert(const char *devname, int datacsum, int packing,
 	struct btrfs_root *image_root;
 	struct btrfs_convert_context cctx;
 	struct btrfs_key key;
-	char *subvol_name = NULL;
+	char subvol_name[SOURCE_FS_NAME_LEN + 8];
 	struct task_ctx ctx;
 	char features_buf[64];
 	struct btrfs_mkfs_config mkfs_cfg;
@@ -2421,15 +1244,13 @@ static int do_convert(const char *devname, int datacsum, int packing,
 	printf("\tnodesize:  %u\n", nodesize);
 	printf("\tfeatures:  %s\n", features_buf);
 
+	memset(&mkfs_cfg, 0, sizeof(mkfs_cfg));
 	mkfs_cfg.label = cctx.volume_name;
 	mkfs_cfg.num_bytes = total_bytes;
 	mkfs_cfg.nodesize = nodesize;
 	mkfs_cfg.sectorsize = blocksize;
 	mkfs_cfg.stripesize = blocksize;
 	mkfs_cfg.features = features;
-	/* New convert need these space */
-	memset(mkfs_cfg.chunk_uuid, 0, BTRFS_UUID_UNPARSED_SIZE);
-	memset(mkfs_cfg.fs_uuid, 0, BTRFS_UUID_UNPARSED_SIZE);
 
 	ret = make_convert_btrfs(fd, &mkfs_cfg, &cctx);
 	if (ret) {
@@ -2443,19 +1264,15 @@ static int do_convert(const char *devname, int datacsum, int packing,
 		error("unable to open ctree");
 		goto fail;
 	}
-	ret = init_btrfs(&mkfs_cfg, root, &cctx, datacsum, packing, noxattr);
+	ret = init_btrfs(&mkfs_cfg, root, &cctx, convert_flags);
 	if (ret) {
 		error("unable to setup the root tree: %d", ret);
 		goto fail;
 	}
 
 	printf("creating %s image file\n", cctx.convert_ops->name);
-	ret = asprintf(&subvol_name, "%s_saved", cctx.convert_ops->name);
-	if (ret < 0) {
-		error("memory allocation failure for subvolume name: %s_saved",
+	snprintf(subvol_name, sizeof(subvol_name), "%s_saved",
 			cctx.convert_ops->name);
-		goto fail;
-	}
 	key.objectid = CONV_IMAGE_SUBVOL_OBJECTID;
 	key.offset = (u64)-1;
 	key.type = BTRFS_ROOT_ITEM_KEY;
@@ -2465,13 +1282,19 @@ static int do_convert(const char *devname, int datacsum, int packing,
 		goto fail;
 	}
 	ret = create_image(image_root, &mkfs_cfg, &cctx, fd,
-			      mkfs_cfg.num_bytes, "image", datacsum);
+			      mkfs_cfg.num_bytes, "image",
+			      convert_flags);
 	if (ret) {
 		error("failed to create %s/image: %d", subvol_name, ret);
 		goto fail;
 	}
 
 	printf("creating btrfs metadata");
+	ret = pthread_mutex_init(&ctx.mutex, NULL);
+	if (ret) {
+		error("failed to initialize mutex: %d", ret);
+		goto fail;
+	}
 	ctx.max_copy_inodes = (cctx.inodes_count - cctx.free_inodes_count);
 	ctx.cur_copy_inodes = 0;
 
@@ -2480,7 +1303,7 @@ static int do_convert(const char *devname, int datacsum, int packing,
 				     &ctx);
 		task_start(ctx.info);
 	}
-	ret = copy_inodes(&cctx, root, datacsum, packing, noxattr, &ctx);
+	ret = copy_inodes(&cctx, root, convert_flags, &ctx);
 	if (ret) {
 		error("error during copy_inodes %d", ret);
 		goto fail;
@@ -2496,14 +1319,12 @@ static int do_convert(const char *devname, int datacsum, int packing,
 		goto fail;
 	}
 
-	free(subvol_name);
-
 	memset(root->fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
-	if (copylabel == 1) {
+	if (convert_flags & CONVERT_FLAG_COPY_LABEL) {
 		__strncpy_null(root->fs_info->super_copy->label,
 				cctx.volume_name, BTRFS_LABEL_SIZE - 1);
 		printf("copy label '%s'\n", root->fs_info->super_copy->label);
-	} else if (copylabel == -1) {
+	} else if (convert_flags & CONVERT_FLAG_SET_LABEL) {
 		strcpy(root->fs_info->super_copy->label, fslabel);
 		printf("set label to '%s'\n", fslabel);
 	}
@@ -2548,479 +1369,404 @@ fail:
 }
 
 /*
- * Check if a non 1:1 mapped chunk can be rolled back.
- * For new convert, it's OK while for old convert it's not.
+ * Read out data of convert image which is in btrfs reserved ranges so we can
+ * use them to overwrite the ranges during rollback.
  */
-static int may_rollback_chunk(struct btrfs_fs_info *fs_info, u64 bytenr)
+static int read_reserved_ranges(struct btrfs_root *root, u64 ino,
+				u64 total_bytes, char *reserved_ranges[])
 {
-	struct btrfs_block_group_cache *bg;
-	struct btrfs_key key;
-	struct btrfs_path path;
-	struct btrfs_root *extent_root = fs_info->extent_root;
-	u64 bg_start;
-	u64 bg_end;
-	int ret;
-
-	bg = btrfs_lookup_first_block_group(fs_info, bytenr);
-	if (!bg)
-		return -ENOENT;
-	bg_start = bg->key.objectid;
-	bg_end = bg->key.objectid + bg->key.offset;
-
-	key.objectid = bg_end;
-	key.type = BTRFS_METADATA_ITEM_KEY;
-	key.offset = 0;
-	btrfs_init_path(&path);
-
-	ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
-	if (ret < 0)
-		return ret;
+	int i;
+	int ret = 0;
 
-	while (1) {
-		struct btrfs_extent_item *ei;
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
 
-		ret = btrfs_previous_extent_item(extent_root, &path, bg_start);
-		if (ret > 0) {
-			ret = 0;
+		if (range->start + range->len >= total_bytes)
 			break;
-		}
-		if (ret < 0)
+		ret = btrfs_read_file(root, ino, range->start, range->len,
+				      reserved_ranges[i]);
+		if (ret < range->len) {
+			error(
+	"failed to read data of convert image, offset=%llu len=%llu ret=%d",
+			      range->start, range->len, ret);
+			if (ret >= 0)
+				ret = -EIO;
 			break;
+		}
+		ret = 0;
+	}
+	return ret;
+}
 
-		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
-		if (key.type == BTRFS_METADATA_ITEM_KEY)
-			continue;
-		/* Now it's EXTENT_ITEM_KEY only */
-		ei = btrfs_item_ptr(path.nodes[0], path.slots[0],
-				    struct btrfs_extent_item);
-		/*
-		 * Found data extent, means this is old convert must follow 1:1
-		 * mapping.
-		 */
-		if (btrfs_extent_flags(path.nodes[0], ei)
-				& BTRFS_EXTENT_FLAG_DATA) {
-			ret = -EINVAL;
+static bool is_subset_of_reserved_ranges(u64 start, u64 len)
+{
+	int i;
+	bool ret = false;
+
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
+
+		if (start >= range->start && start + len <= range_end(range)) {
+			ret = true;
 			break;
 		}
 	}
-	btrfs_release_path(&path);
 	return ret;
 }
 
-static int may_rollback(struct btrfs_root *root)
+static bool is_chunk_direct_mapped(struct btrfs_fs_info *fs_info, u64 start)
 {
-	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;
+	struct cache_extent *ce;
+	struct map_lookup *map;
+	bool ret = false;
+
+	ce = search_cache_extent(&fs_info->mapping_tree.cache_tree, start);
+	if (!ce)
+		goto out;
+	if (ce->start > start || ce->start + ce->size < start)
+		goto out;
+
+	map = container_of(ce, struct map_lookup, ce);
+
+	/* Not SINGLE chunk */
+	if (map->num_stripes != 1)
+		goto out;
+
+	/* Chunk's logical doesn't match with phisical, not 1:1 mapped */
+	if (map->ce.start != map->stripes[0].physical)
+		goto out;
+	ret = true;
+out:
+	return ret;
+}
+
+/*
+ * Iterate all file extents of the convert image.
+ *
+ * All file extents except ones in btrfs_reserved_ranges must be mapped 1:1
+ * on disk. (Means thier file_offset must match their on disk bytenr)
+ *
+ * File extents in reserved ranges can be relocated to other place, and in
+ * that case we will read them out for later use.
+ */
+static int check_convert_image(struct btrfs_root *image_root, u64 ino,
+			       u64 total_size, char *reserved_ranges[])
+{
+	struct btrfs_key key;
+	struct btrfs_path path;
+	struct btrfs_fs_info *fs_info = image_root->fs_info;
+	u64 checked_bytes = 0;
 	int ret;
 
-	if (btrfs_super_num_devices(info->super_copy) != 1)
-		goto fail;
+	key.objectid = ino;
+	key.offset = 0;
+	key.type = BTRFS_EXTENT_DATA_KEY;
 
-	bytenr = BTRFS_SUPER_INFO_OFFSET;
-	total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+	btrfs_init_path(&path);
+	ret = btrfs_search_slot(NULL, image_root, &key, &path, 0, 0);
+	/*
+	 * It's possible that some fs doesn't store any (including sb)
+	 * data into 0~1M range, and NO_HOLES is enabled.
+	 *
+	 * So we only need to check if ret < 0
+	 */
+	if (ret < 0) {
+		error("failed to iterate file extents at offset 0: %s",
+			strerror(-ret));
+		btrfs_release_path(&path);
+		return ret;
+	}
 
+	/* Loop from the first file extents */
 	while (1) {
-		ret = btrfs_map_block(&info->mapping_tree, WRITE, bytenr,
-				      &length, &multi, 0, NULL);
-		if (ret) {
-			if (ret == -ENOENT) {
-				/* removed block group at the tail */
-				if (length == (u64)-1)
-					break;
+		struct btrfs_file_extent_item *fi;
+		struct extent_buffer *leaf = path.nodes[0];
+		u64 disk_bytenr;
+		u64 file_offset;
+		u64 ram_bytes;
+		int slot = path.slots[0];
 
-				/* removed block group in the middle */
-				goto next;
-			}
-			goto fail;
+		if (slot >= btrfs_header_nritems(leaf))
+			goto next;
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+
+		/*
+		 * Iteration is done, exit normally, we have extra check out of
+		 * the loop
+		 */
+		if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY) {
+			ret = 0;
+			break;
+		}
+		file_offset = key.offset;
+		fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+		if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG) {
+			ret = -EINVAL;
+			error(
+		"ino %llu offset %llu doesn't have a regular file extent",
+				ino, file_offset);
+			break;
+		}
+		if (btrfs_file_extent_compression(leaf, fi) ||
+		    btrfs_file_extent_encryption(leaf, fi) ||
+		    btrfs_file_extent_other_encoding(leaf, fi)) {
+			ret = -EINVAL;
+			error(
+			"ino %llu offset %llu doesn't have a plain file extent",
+				ino, file_offset);
+			break;
 		}
 
-		num_stripes = multi->num_stripes;
-		physical = multi->stripes[0].physical;
-		free(multi);
+		disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+		ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
 
-		if (num_stripes != 1) {
-			error("num stripes for bytenr %llu is not 1", bytenr);
-			goto fail;
-		}
+		checked_bytes += ram_bytes;
+		/* Skip hole */
+		if (disk_bytenr == 0)
+			goto next;
 
 		/*
-		 * Extra check for new convert, as metadata chunk from new
-		 * convert is much more free than old convert, it doesn't need
-		 * to do 1:1 mapping.
+		 * Most file extents must be 1:1 mapped, which means 2 things:
+		 * 1) File extent file offset == disk_bytenr
+		 * 2) That data chunk's logical == chunk's physical
+		 *
+		 * So file extent's file offset == physical position on disk.
+		 *
+		 * And after rolling back btrfs reserved range, other part
+		 * remains what old fs used to be.
 		 */
-		if (physical != bytenr) {
+		if (file_offset != disk_bytenr ||
+		    !is_chunk_direct_mapped(fs_info, disk_bytenr)) {
 			/*
-			 * Check if it's a metadata chunk and has only metadata
-			 * extent.
+			 * Only file extent in btrfs reserved ranges are
+			 * allowed to be non-1:1 mapped
 			 */
-			ret = may_rollback_chunk(info, bytenr);
-			if (ret < 0)
-				goto fail;
+			if (!is_subset_of_reserved_ranges(file_offset,
+							ram_bytes)) {
+				ret = -EINVAL;
+				error(
+		"ino %llu offset %llu file extent should not be relocated",
+					ino, file_offset);
+				break;
+			}
 		}
 next:
-		bytenr += length;
-		if (bytenr >= total_bytes)
+		ret = btrfs_next_item(image_root, &path);
+		if (ret) {
+			if (ret > 0)
+				ret = 0;
 			break;
+		}
 	}
-	return 0;
-fail:
-	return -1;
+	btrfs_release_path(&path);
+	/*
+	 * For HOLES mode (without NO_HOLES), we must ensure file extents
+	 * cover the whole range of the image
+	 */
+	if (!ret && !btrfs_fs_incompat(fs_info, NO_HOLES)) {
+		if (checked_bytes != total_size) {
+			ret = -EINVAL;
+			error("inode %llu has some file extents not checked",
+				ino);
+			return ret;
+		}
+	}
+
+	/* So far so good, read old data located in btrfs reserved ranges */
+	ret = read_reserved_ranges(image_root, ino, total_size,
+				   reserved_ranges);
+	return ret;
 }
 
+/*
+ * btrfs rollback is just reverted convert:
+ * |<---------------Btrfs fs------------------------------>|
+ * |<-   Old data chunk  ->|< new chunk (D/M/S)>|<- ODC  ->|
+ * |<-Old-FE->| |<-Old-FE->|<- Btrfs extents  ->|<-Old-FE->|
+ *                           ||
+ *                           \/
+ * |<------------------Old fs----------------------------->|
+ * |<- used ->| |<- used ->|                    |<- used ->|
+ *
+ * However things are much easier than convert, we don't really need to
+ * do the complex space calculation, but only to handle btrfs reserved space
+ *
+ * |<---------------------------Btrfs fs----------------------------->|
+ * |   RSV 1   |  | Old  |   |    RSV 2  | | Old  | |   RSV 3   |
+ * |   0~1M    |  | Fs   |   | SB2 + 64K | | Fs   | | SB3 + 64K |
+ *
+ * On the other hande, the converted fs image in btrfs is a completely 
+ * valid old fs.
+ *
+ * |<-----------------Converted fs image in btrfs-------------------->|
+ * |   RSV 1   |  | Old  |   |    RSV 2  | | Old  | |   RSV 3   |
+ * | Relocated |  | Fs   |   | Relocated | | Fs   | | Relocated |
+ *
+ * Used space in fs image should be at the same physical position on disk.
+ * We only need to recover the data in reserved ranges, so the whole
+ * old fs is back.
+ *
+ * The idea to rollback is also straightforward, we just "read" out the data
+ * of reserved ranges, and write them back to there they should be.
+ * Then the old fs is back.
+ */
 static int do_rollback(const char *devname)
 {
-	int fd = -1;
-	int ret;
-	int i;
 	struct btrfs_root *root;
 	struct btrfs_root *image_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_fs_info *fs_info;
 	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;
+	struct btrfs_dir_item *dir;
+	struct btrfs_inode_item *inode_item;
+	char *image_name = "image";
+	char *reserved_ranges[ARRAY_SIZE(btrfs_reserved_ranges)] = { NULL };
 	u64 total_bytes;
-	u32 sectorsize;
+	u64 fsize;
+	u64 root_dir;
+	u64 ino;
+	int fd = -1;
+	int ret;
+	int i;
 
-	extent_io_tree_init(&io_tree);
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
 
+		reserved_ranges[i] = calloc(1, range->len);
+		if (!reserved_ranges[i]) {
+			ret = -ENOMEM;
+			goto free_mem;
+		}
+	}
 	fd = open(devname, O_RDWR);
 	if (fd < 0) {
 		error("unable to open %s: %s", devname, strerror(errno));
-		goto fail;
+		ret = -EIO;
+		goto free_mem;
 	}
+	fsize = lseek(fd, 0, SEEK_END);
 	root = open_ctree_fd(fd, devname, 0, OPEN_CTREE_WRITES);
 	if (!root) {
 		error("unable to open ctree");
-		goto fail;
+		ret = -EIO;
+		goto free_mem;
 	}
-	ret = may_rollback(root);
-	if (ret < 0) {
-		error("unable to do rollback: %d", ret);
-		goto fail;
-	}
-
-	sectorsize = root->sectorsize;
-	buf = malloc(sectorsize);
-	if (!buf) {
-		error("unable to allocate memory");
-		goto fail;
-	}
-
-	btrfs_init_path(&path);
+	fs_info = root->fs_info;
 
+	/*
+	 * Search root backref first, or after subvolume deletion (orphan),
+	 * we can still rollback the image.
+	 */
 	key.objectid = CONV_IMAGE_SUBVOL_OBJECTID;
 	key.type = BTRFS_ROOT_BACKREF_KEY;
 	key.offset = BTRFS_FS_TREE_OBJECTID;
-	ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, &path, 0,
-				0);
+	btrfs_init_path(&path);
+	ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, &path, 0, 0);
 	btrfs_release_path(&path);
 	if (ret > 0) {
-		error("unable to convert ext2 image subvolume, is it deleted?");
-		goto fail;
+		error("unable to find ext2 image subvolume, is it deleted?");
+		ret = -ENOENT;
+		goto close_fs;
 	} else if (ret < 0) {
-		error("unable to open ext2_saved, id %llu: %s",
-			(unsigned long long)key.objectid, strerror(-ret));
-		goto fail;
+		error("failed to find ext2 image subvolume: %s",
+			strerror(-ret));
+		goto close_fs;
 	}
 
+	/* Search convert subvolume */
 	key.objectid = CONV_IMAGE_SUBVOL_OBJECTID;
 	key.type = BTRFS_ROOT_ITEM_KEY;
 	key.offset = (u64)-1;
-	image_root = btrfs_read_fs_root(root->fs_info, &key);
-	if (!image_root || IS_ERR(image_root)) {
-		error("unable to open subvolume %llu: %ld",
-			(unsigned long long)key.objectid, PTR_ERR(image_root));
-		goto fail;
+	image_root = btrfs_read_fs_root(fs_info, &key);
+	if (IS_ERR(image_root)) {
+		ret = PTR_ERR(image_root);
+		error("failed to open convert image subvolume: %s",
+			strerror(-ret));
+		goto close_fs;
 	}
 
-	name = "image";
-	root_dir = btrfs_root_dirid(&root->root_item);
-	dir = btrfs_lookup_dir_item(NULL, image_root, &path,
-				   root_dir, name, strlen(name), 0);
+	/* Search the image file */
+	root_dir = btrfs_root_dirid(&image_root->root_item);
+	dir = btrfs_lookup_dir_item(NULL, image_root, &path, root_dir,
+			image_name, strlen(image_name), 0);
+
 	if (!dir || IS_ERR(dir)) {
-		error("unable to find file %s: %ld", name, PTR_ERR(dir));
-		goto fail;
+		btrfs_release_path(&path);
+		if (dir)
+			ret = PTR_ERR(dir);
+		else
+			ret = -ENOENT;
+		error("failed to locate file %s: %s", image_name,
+			strerror(-ret));
+		goto close_fs;
 	}
-	leaf = path.nodes[0];
-	btrfs_dir_item_key_to_cpu(leaf, dir, &key);
+	btrfs_dir_item_key_to_cpu(path.nodes[0], dir, &key);
 	btrfs_release_path(&path);
 
-	objectid = key.objectid;
+	/* Get total size of the original image */
+	ino = key.objectid;
 
 	ret = btrfs_lookup_inode(NULL, image_root, &path, &key, 0);
-	if (ret) {
-		error("unable to find inode item: %d", ret);
-		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(&path);
 
-	key.objectid = objectid;
-	key.offset = 0;
-	key.type = BTRFS_EXTENT_DATA_KEY;
-	ret = btrfs_search_slot(NULL, image_root, &key, &path, 0, 0);
-	if (ret != 0) {
-		error("unable to find first file extent: %d", ret);
+	if (ret < 0) {
 		btrfs_release_path(&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 ||
-		    key.type != 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);
-		/*
-		 * Here we must take consideration of old and new convert
-		 * behavior.
-		 * For old convert case, sign, there is no consist chunk type
-		 * that will cover the extent. META/DATA/SYS are all possible.
-		 * Just ensure relocate one is in SYS chunk.
-		 * For new convert case, they are all covered by DATA chunk.
-		 *
-		 * So, there is not valid chunk type check for it now.
-		 */
-		if (cache1 != cache2)
-			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]++;
+		error("unable to find inode %llu: %s", ino, strerror(-ret));
+		goto close_fs;
 	}
+	inode_item = btrfs_item_ptr(path.nodes[0], path.slots[0],
+				    struct btrfs_inode_item);
+	total_bytes = btrfs_inode_size(path.nodes[0], inode_item);
 	btrfs_release_path(&path);
 
-	if (offset < total_bytes) {
-		error("unable to build extent mapping (offset %llu, total_bytes %llu)",
-				(unsigned long long)offset,
-				(unsigned long long)total_bytes);
-		error("converted filesystem after balance is unable to rollback");
-		goto fail;
+	/* Check if we can rollback the image */
+	ret = check_convert_image(image_root, ino, total_bytes, reserved_ranges);
+	if (ret < 0) {
+		error("old fs image can't be rolled back");
+		goto close_fs;
 	}
+close_fs:
+	btrfs_release_path(&path);
+	close_ctree_fs_info(fs_info);
+	if (ret)
+		goto free_mem;
 
-	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)) {
-		error("no backup for the first extent");
-		goto fail;
-	}
-	/* force no allocation from system block group */
-	root->fs_info->system_allocs = -1;
-	trans = btrfs_start_transaction(root, 1);
-	if (!trans) {
-		error("unable to start transaction");
-		goto fail;
-	}
 	/*
-	 * recow the whole chunk tree, this will remove all chunk tree blocks
-	 * from system block group
+	 * Everything is OK, just write back old fs data into btrfs reserved
+	 * ranges
+	 *
+	 * Here, we starts from the backup blocks first, so if something goes
+	 * wrong, the fs is still mountable
 	 */
-	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;
+	for (i = ARRAY_SIZE(btrfs_reserved_ranges) - 1; i >= 0; i--) {
+		u64 real_size;
+		const struct simple_range *range = &btrfs_reserved_ranges[i];
 
-		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
-		btrfs_release_path(&path);
-	}
-	btrfs_release_path(&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) {
-		error(
-	"unable to empty system block group (num_bytes %llu, first_free %llu",
-				(unsigned long long)num_bytes,
-				(unsigned long long)first_free);
-		goto fail;
-	}
-	/* create a system chunk that maps the whole device */
-	ret = prepare_system_chunk_sb(root->fs_info->super_copy);
-	if (ret) {
-		error("unable to update system chunk: %d", ret);
-		goto fail;
-	}
-
-	ret = btrfs_commit_transaction(trans, root);
-	if (ret) {
-		error("transaction commit failed: %d", ret);
-		goto fail;
-	}
-
-	ret = close_ctree(root);
-	if (ret) {
-		error("close_ctree failed: %d", 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);
-		if (ret != sectorsize) {
-			error("zeroing superblock mirror %d failed: %d",
-					i, ret);
-			goto fail;
-		}
-	}
-
-	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);
+		if (range_end(range) >= fsize)
+			continue;
 
-		while (start <= end) {
-			if (start == BTRFS_SUPER_INFO_OFFSET) {
-				sb_bytenr = bytenr;
-				goto next_sector;
-			}
-			ret = pread(fd, buf, sectorsize, bytenr);
-			if (ret < 0) {
-				error("reading superblock at %llu failed: %d",
-						(unsigned long long)bytenr, ret);
-				goto fail;
-			}
-			BUG_ON(ret != sectorsize);
-			ret = pwrite(fd, buf, sectorsize, start);
-			if (ret < 0) {
-				error("writing superblock at %llu failed: %d",
-						(unsigned long long)start, ret);
-				goto fail;
-			}
-			BUG_ON(ret != sectorsize);
-next_sector:
-			start += sectorsize;
-			bytenr += sectorsize;
+		real_size = min(range_end(range), fsize) - range->start;
+		ret = pwrite(fd, reserved_ranges[i], real_size, range->start);
+		if (ret < real_size) {
+			if (ret < 0)
+				ret = -errno;
+			else
+				ret = -EIO;
+			error("failed to recover range [%llu, %llu): %s",
+			      range->start, real_size, strerror(-ret));
+			goto free_mem;
 		}
+		ret = 0;
 	}
 
-	ret = fsync(fd);
-	if (ret < 0) {
-		error("fsync failed: %s", strerror(errno));
-		goto fail;
-	}
-	/*
-	 * finally, overwrite btrfs super block.
-	 */
-	ret = pread(fd, buf, sectorsize, sb_bytenr);
-	if (ret < 0) {
-		error("reading primary superblock failed: %s",
-				strerror(errno));
-		goto fail;
-	}
-	BUG_ON(ret != sectorsize);
-	ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
-	if (ret < 0) {
-		error("writing primary superblock failed: %s",
-				strerror(errno));
-		goto fail;
-	}
-	BUG_ON(ret != sectorsize);
-	ret = fsync(fd);
-	if (ret < 0) {
-		error("fsync failed: %s", strerror(errno));
-		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);
-	error("rollback aborted");
-	return -1;
+free_mem:
+	for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++)
+		free(reserved_ranges[i]);
+	if (ret)
+		error("rollback failed");
+	else
+		printf("rollback succeeded\n");
+	return ret;
 }
 
 static void print_usage(void)
@@ -3096,7 +1842,7 @@ int main(int argc, char *argv[])
 				rollback = 1;
 				break;
 			case 'l':
-				copylabel = -1;
+				copylabel = CONVERT_FLAG_SET_LABEL;
 				if (strlen(optarg) >= BTRFS_LABEL_SIZE) {
 					warning(
 					"label too long, trimmed to %d bytes",
@@ -3105,7 +1851,7 @@ int main(int argc, char *argv[])
 				__strncpy_null(fslabel, optarg, BTRFS_LABEL_SIZE - 1);
 				break;
 			case 'L':
-				copylabel = 1;
+				copylabel = CONVERT_FLAG_COPY_LABEL;
 				break;
 			case 'p':
 				progress = 1;
@@ -3178,8 +1924,13 @@ int main(int argc, char *argv[])
 	if (rollback) {
 		ret = do_rollback(file);
 	} else {
-		ret = do_convert(file, datacsum, packing, noxattr, nodesize,
-				copylabel, fslabel, progress, features);
+		u32 cf = 0;
+
+		cf |= datacsum ? CONVERT_FLAG_DATACSUM : 0;
+		cf |= packing ? CONVERT_FLAG_INLINE_DATA : 0;
+		cf |= noxattr ? 0 : CONVERT_FLAG_XATTR;
+		cf |= copylabel;
+		ret = do_convert(file, cf, nodesize, fslabel, progress, features);
 	}
 	if (ret)
 		return 1;