Function blst_copy

freebsd/kern/subr_blist.c:933–980

* BLST_COPY() - copy one radix tree to another * * Locates free space in the source tree and frees it in the destination * tree. The space may not already be free in the destination. */

 *	tree.  The space may not already be free in the destination.
 */
static void
blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix, blist_t dest,
    daddr_t count)
{
	daddr_t endBlk, i, skip;

	/*
	 * Leaf node
	 */

	if (radix == 1) {
		u_daddr_t v = scan->bm_bitmap;

		if (v == (u_daddr_t)-1) {
			blist_free(dest, blk, count);
		} else if (v != 0) {
			int i;

			for (i = 0; i < count; ++i) {
				if (v & ((u_daddr_t)1 << i))
					blist_free(dest, blk + i, 1);
			}
		}
		return;
	}

	/*
	 * Meta node
	 */

	if (scan->bm_bitmap == 0) {
		/*
		 * Source all allocated, leave dest allocated
		 */
		return;
	}

	endBlk = blk + count;
	skip = radix_to_skip(radix);
	for (i = 1; blk < endBlk; i += skip) {
		blk += radix;
		count = radix;
		if (blk >= endBlk)
			count -= blk - endBlk;
		blst_copy(&scan[i], blk - radix,
		    radix / BLIST_RADIX, dest, count);
	}
}

/*
 * BLST_LEAF_FILL() -	allocate specific blocks in leaf bitmap