Function vdev_trim_change_state

freebsd/contrib/openzfs/module/zfs/vdev_trim.c:268–357

* Update the on-disk state of a manual TRIM. This is called to request * that a TRIM be started/suspended/canceled, or to change one of the * TRIM options (partial, secure, rate). */

 * TRIM options (partial, secure, rate).
 */
static void
vdev_trim_change_state(vdev_t *vd, vdev_trim_state_t new_state,
    uint64_t rate, boolean_t partial, boolean_t secure)
{
	ASSERT(MUTEX_HELD(&vd->vdev_trim_lock));
	spa_t *spa = vd->vdev_spa;

	if (new_state == vd->vdev_trim_state)
		return;

	/*
	 * Copy the vd's guid, this will be freed by the sync task.
	 */
	uint64_t *guid = kmem_zalloc(sizeof (uint64_t), KM_SLEEP);
	*guid = vd->vdev_guid;

	/*
	 * If we're suspending, then preserve the original start time.
	 */
	if (vd->vdev_trim_state != VDEV_TRIM_SUSPENDED) {
		vd->vdev_trim_action_time = gethrestime_sec();
	}

	/*
	 * If we're activating, then preserve the requested rate and trim
	 * method.  Setting the last offset and rate to UINT64_MAX is used
	 * as a sentinel to indicate they should be reset to default values.
	 */
	if (new_state == VDEV_TRIM_ACTIVE) {
		if (vd->vdev_trim_state == VDEV_TRIM_COMPLETE ||
		    vd->vdev_trim_state == VDEV_TRIM_CANCELED) {
			vd->vdev_trim_last_offset = UINT64_MAX;
			vd->vdev_trim_rate = UINT64_MAX;
			vd->vdev_trim_partial = UINT64_MAX;
			vd->vdev_trim_secure = UINT64_MAX;
		}

		if (rate != 0)
			vd->vdev_trim_rate = rate;

		if (partial != 0)
			vd->vdev_trim_partial = partial;

		if (secure != 0)
			vd->vdev_trim_secure = secure;
	}

	vdev_trim_state_t old_state = vd->vdev_trim_state;
	boolean_t resumed = (old_state == VDEV_TRIM_SUSPENDED);
	vd->vdev_trim_state = new_state;

	dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
	VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
	dsl_sync_task_nowait(spa_get_dsl(spa), vdev_trim_zap_update_sync,
	    guid, tx);

	switch (new_state) {
	case VDEV_TRIM_ACTIVE: