> - while (xfs_btree_islastblock(acur.cnt, 0)) {
> + error = xfs_btree_islastblock(acur.cnt, 0, &is_last);
> + if (error)
> + goto out;
> + while (is_last) {
This transformation looks actually ok, but is highly non-obvious.
I think you want a prep patch just killing the pointless while first.
