+ if (!(spa->spa_import_flags & ZFS_IMPORT_MISSING_LOG)) {
+ nvlist_t **child, *nv;
+ uint64_t idx = 0;
+
+ child = kmem_alloc(rvd->vdev_children * sizeof (nvlist_t **),
+ KM_SLEEP);
+ VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+
+ for (c = 0; c < rvd->vdev_children; c++) {
+ vdev_t *tvd = rvd->vdev_child[c];
+ vdev_t *mtvd = mrvd->vdev_child[c];
+
+ if (tvd->vdev_ops == &vdev_missing_ops &&
+ mtvd->vdev_ops != &vdev_missing_ops &&
+ mtvd->vdev_islog)
+ child[idx++] = vdev_config_generate(spa, mtvd,
+ B_FALSE, 0);
+ }
+
+ if (idx) {
+ VERIFY(nvlist_add_nvlist_array(nv,
+ ZPOOL_CONFIG_CHILDREN, child, idx) == 0);
+ VERIFY(nvlist_add_nvlist(spa->spa_load_info,
+ ZPOOL_CONFIG_MISSING_DEVICES, nv) == 0);
+
+ for (i = 0; i < idx; i++)
+ nvlist_free(child[i]);
+ }
+ nvlist_free(nv);
+ kmem_free(child, rvd->vdev_children * sizeof (char **));
+ }
+
+ /*
+ * Compare the root vdev tree with the information we have
+ * from the MOS config (mrvd). Check each top-level vdev
+ * with the corresponding MOS config top-level (mtvd).
+ */
+ for (c = 0; c < rvd->vdev_children; c++) {
+ vdev_t *tvd = rvd->vdev_child[c];
+ vdev_t *mtvd = mrvd->vdev_child[c];
+
+ /*
+ * Resolve any "missing" vdevs in the current configuration.
+ * If we find that the MOS config has more accurate information
+ * about the top-level vdev then use that vdev instead.
+ */
+ if (tvd->vdev_ops == &vdev_missing_ops &&
+ mtvd->vdev_ops != &vdev_missing_ops) {
+
+ if (!(spa->spa_import_flags & ZFS_IMPORT_MISSING_LOG))
+ continue;
+
+ /*
+ * Device specific actions.
+ */
+ if (mtvd->vdev_islog) {
+ spa_set_log_state(spa, SPA_LOG_CLEAR);
+ } else {
+ /*
+ * XXX - once we have 'readonly' pool
+ * support we should be able to handle
+ * missing data devices by transitioning
+ * the pool to readonly.
+ */
+ continue;
+ }
+
+ /*
+ * Swap the missing vdev with the data we were
+ * able to obtain from the MOS config.
+ */
+ vdev_remove_child(rvd, tvd);
+ vdev_remove_child(mrvd, mtvd);
+
+ vdev_add_child(rvd, mtvd);
+ vdev_add_child(mrvd, tvd);
+
+ spa_config_exit(spa, SCL_ALL, FTAG);
+ vdev_load(mtvd);
+ spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);