xfs_iext_alloc_node
struct xfs_iext_node *node = xfs_iext_alloc_node(NODE_SIZE);
struct xfs_iext_node *new = xfs_iext_alloc_node(NODE_SIZE);
struct xfs_iext_leaf *new = xfs_iext_alloc_node(NODE_SIZE);
ifp->if_data = xfs_iext_alloc_node(sizeof(struct xfs_iext_rec));