blst_leaf_alloc
static swblk_t blst_leaf_alloc(blmeta_t *scan, swblk_t blkat,
blk = blst_leaf_alloc(bl->bl_root, 0, 0, count);
blk = blst_leaf_alloc(bl->bl_root, blkat, 0, count);
r = blst_leaf_alloc(&scan[i], blkat,