Function vdev_dtl_reassess

freebsd/contrib/openzfs/module/zfs/vdev.c:2811–2970

* Reassess DTLs after a config change or scrub completion. If txg == 0 no * write operations will be issued to the pool. */

 * write operations will be issued to the pool.
 */
void
vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg,
    boolean_t scrub_done, boolean_t rebuild_done)
{
	spa_t *spa = vd->vdev_spa;
	avl_tree_t reftree;
	int minref;

	ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);

	for (int c = 0; c < vd->vdev_children; c++)
		vdev_dtl_reassess(vd->vdev_child[c], txg,
		    scrub_txg, scrub_done, rebuild_done);

	if (vd == spa->spa_root_vdev || !vdev_is_concrete(vd) || vd->vdev_aux)
		return;

	if (vd->vdev_ops->vdev_op_leaf) {
		dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
		vdev_rebuild_t *vr = &vd->vdev_top->vdev_rebuild_config;
		boolean_t check_excise = B_FALSE;
		boolean_t wasempty = B_TRUE;

		mutex_enter(&vd->vdev_dtl_lock);

		/*
		 * If requested, pretend the scan or rebuild completed cleanly.
		 */
		if (zfs_scan_ignore_errors) {
			if (scn != NULL)
				scn->scn_phys.scn_errors = 0;
			if (vr != NULL)
				vr->vr_rebuild_phys.vrp_errors = 0;
		}

		if (scrub_txg != 0 &&
		    !range_tree_is_empty(vd->vdev_dtl[DTL_MISSING])) {
			wasempty = B_FALSE;
			zfs_dbgmsg("guid:%llu txg:%llu scrub:%llu started:%d "
			    "dtl:%llu/%llu errors:%llu",
			    (u_longlong_t)vd->vdev_guid, (u_longlong_t)txg,
			    (u_longlong_t)scrub_txg, spa->spa_scrub_started,
			    (u_longlong_t)vdev_dtl_min(vd),
			    (u_longlong_t)vdev_dtl_max(vd),
			    (u_longlong_t)(scn ? scn->scn_phys.scn_errors : 0));
		}

		/*
		 * If we've completed a scrub/resilver or a rebuild cleanly
		 * then determine if this vdev should remove any DTLs. We
		 * only want to excise regions on vdevs that were available
		 * during the entire duration of this scan.
		 */
		if (rebuild_done &&
		    vr != NULL && vr->vr_rebuild_phys.vrp_errors == 0) {
			check_excise = B_TRUE;
		} else {
			if (spa->spa_scrub_started ||