+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_disk_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,