Function vdev_state_dirty

freebsd/contrib/openzfs/module/zfs/vdev.c:4661–4682

* Mark a top-level vdev's state as dirty, so that the next pass of * spa_sync() can convert this into vdev_config_dirty(). We distinguish * the state changes from larger config changes because they require * much less locking, and are often needed for administrative actions. */

 * much less locking, and are often needed for administrative actions.
 */
void
vdev_state_dirty(vdev_t *vd)
{
	spa_t *spa = vd->vdev_spa;

	ASSERT(spa_writeable(spa));
	ASSERT(vd == vd->vdev_top);

	/*
	 * The state list is protected by the SCL_STATE lock.  The caller
	 * must either hold SCL_STATE as writer, or must be the sync thread
	 * (which holds SCL_STATE as reader).  There's only one sync thread,
	 * so this is sufficient to ensure mutual exclusion.
	 */
	ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
	    (dsl_pool_sync_context(spa_get_dsl(spa)) &&
	    spa_config_held(spa, SCL_STATE, RW_READER)));

	if (!list_link_active(&vd->vdev_state_dirty_node) &&
	    vdev_is_concrete(vd))
		list_insert_head(&spa->spa_state_dirty_list, vd);
}

void
vdev_state_clean(vdev_t *vd)