Function space_map_write

freebsd/contrib/openzfs/module/zfs/space_map.c:754–791

* Note: This function manipulates the state of the given space map but * does not hold any locks implicitly. Thus the caller is responsible * for synchronizing writes to the space map. */

 * for synchronizing writes to the space map.
 */
void
space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
    uint64_t vdev_id, dmu_tx_t *tx)
{
	ASSERT(dsl_pool_sync_context(dmu_objset_pool(sm->sm_os)));
	VERIFY3U(space_map_object(sm), !=, 0);

	dmu_buf_will_dirty(sm->sm_dbuf, tx);

	/*
	 * This field is no longer necessary since the in-core space map
	 * now contains the object number but is maintained for backwards
	 * compatibility.
	 */
	sm->sm_phys->smp_object = sm->sm_object;

	if (range_tree_is_empty(rt)) {
		VERIFY3U(sm->sm_object, ==, sm->sm_phys->smp_object);
		return;
	}

	if (maptype == SM_ALLOC)
		sm->sm_phys->smp_alloc += range_tree_space(rt);
	else
		sm->sm_phys->smp_alloc -= range_tree_space(rt);

	uint64_t nodes = zfs_btree_numnodes(&rt->rt_root);
	uint64_t rt_space = range_tree_space(rt);

	space_map_write_impl(sm, rt, maptype, vdev_id, tx);

	/*
	 * Ensure that the space_map's accounting wasn't changed
	 * while we were in the middle of writing it out.
	 */
	VERIFY3U(nodes, ==, zfs_btree_numnodes(&rt->rt_root));
	VERIFY3U(range_tree_space(rt), ==, rt_space);
}

static int
space_map_open_impl(space_map_t *sm)