Function vdev_validate

freebsd/contrib/openzfs/module/zfs/vdev.c:2050–2233

* Called once the vdevs are all opened, this routine validates the label * contents. This needs to be done before vdev_load() so that we don't * inadvertently do repair I/Os to the wrong device. * * This function will only return failure if one of the vdevs indicates that it * has since been destroyed or exported. This is only possible if * /etc/zfs/zpool.cache was readonly at the time. Ot

 * will be updated but the function will return 0.
 */
int
vdev_validate(vdev_t *vd)
{
	spa_t *spa = vd->vdev_spa;
	nvlist_t *label;
	uint64_t guid = 0, aux_guid = 0, top_guid;
	uint64_t state;
	nvlist_t *nvl;
	uint64_t txg;

	if (vdev_validate_skip)
		return (0);

	for (uint64_t c = 0; c < vd->vdev_children; c++)
		if (vdev_validate(vd->vdev_child[c]) != 0)
			return (SET_ERROR(EBADF));

	/*
	 * If the device has already failed, or was marked offline, don't do
	 * any further validation.  Otherwise, label I/O will fail and we will
	 * overwrite the previous state.
	 */
	if (!vd->vdev_ops->vdev_op_leaf || !vdev_readable(vd))
		return (0);

	/*
	 * If we are performing an extreme rewind, we allow for a label that
	 * was modified at a point after the current txg.
	 * If config lock is not held do not check for the txg. spa_sync could
	 * be updating the vdev's label before updating spa_last_synced_txg.
	 */
	if (spa->spa_extreme_rewind || spa_last_synced_txg(spa) == 0 ||
	    spa_config_held(spa, SCL_CONFIG, RW_WRITER) != SCL_CONFIG)
		txg = UINT64_MAX;
	else
		txg = spa_last_synced_txg(spa);

	if ((label = vdev_label_read_config(vd, txg)) == NULL) {
		vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
		    VDEV_AUX_BAD_LABEL);
		vdev_dbgmsg(vd, "vdev_validate: failed reading config for "
		    "txg %llu", (u_longlong_t)txg);
		return (0);
	}

	/*
	 * Determine if this vdev has been split off into another
	 * pool.  If so, then refuse to open it.
	 */
	if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_SPLIT_GUID,
	    &aux_guid) == 0 && aux_guid == spa_guid(spa)) {
		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
		    VDEV_AUX_SPLIT_POOL);
		nvlist_free(label);
		vdev_dbgmsg(vd, "vdev_validate: vdev split into other pool");
		return (0);
	}