btrfs_delayed_refs_rsv_release
btrfs_delayed_refs_rsv_release(fs_info, 1, 0);
btrfs_delayed_refs_rsv_release(fs_info, 0, csum_leaves);
void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums);
btrfs_delayed_refs_rsv_release(fs_info, 0, nr_csums);
btrfs_delayed_refs_rsv_release(fs_info, 1, 0);