+static void
+vdev_copy_path_impl(vdev_t *svd, vdev_t *dvd)
+{
+ if (svd->vdev_path != NULL && dvd->vdev_path != NULL) {
+ if (strcmp(svd->vdev_path, dvd->vdev_path) != 0) {
+ zfs_dbgmsg("vdev_copy_path: vdev %llu: path changed "
+ "from '%s' to '%s'", (u_longlong_t)dvd->vdev_guid,
+ dvd->vdev_path, svd->vdev_path);
+ spa_strfree(dvd->vdev_path);
+ dvd->vdev_path = spa_strdup(svd->vdev_path);
+ }
+ } else if (svd->vdev_path != NULL) {
+ dvd->vdev_path = spa_strdup(svd->vdev_path);
+ zfs_dbgmsg("vdev_copy_path: vdev %llu: path set to '%s'",
+ (u_longlong_t)dvd->vdev_guid, dvd->vdev_path);
+ }
+}
+
+/*
+ * Recursively copy vdev paths from one vdev to another. Source and destination
+ * vdev trees must have same geometry otherwise return error. Intended to copy
+ * paths from userland config into MOS config.
+ */
+int
+vdev_copy_path_strict(vdev_t *svd, vdev_t *dvd)
+{
+ if ((svd->vdev_ops == &vdev_missing_ops) ||
+ (svd->vdev_ishole && dvd->vdev_ishole) ||
+ (dvd->vdev_ops == &vdev_indirect_ops))
+ return (0);
+
+ if (svd->vdev_ops != dvd->vdev_ops) {
+ vdev_dbgmsg(svd, "vdev_copy_path: vdev type mismatch: %s != %s",
+ svd->vdev_ops->vdev_op_type, dvd->vdev_ops->vdev_op_type);
+ return (SET_ERROR(EINVAL));
+ }
+
+ if (svd->vdev_guid != dvd->vdev_guid) {
+ vdev_dbgmsg(svd, "vdev_copy_path: guids mismatch (%llu != "
+ "%llu)", (u_longlong_t)svd->vdev_guid,
+ (u_longlong_t)dvd->vdev_guid);
+ return (SET_ERROR(EINVAL));
+ }
+
+ if (svd->vdev_children != dvd->vdev_children) {
+ vdev_dbgmsg(svd, "vdev_copy_path: children count mismatch: "
+ "%llu != %llu", (u_longlong_t)svd->vdev_children,
+ (u_longlong_t)dvd->vdev_children);
+ return (SET_ERROR(EINVAL));
+ }
+
+ for (uint64_t i = 0; i < svd->vdev_children; i++) {
+ int error = vdev_copy_path_strict(svd->vdev_child[i],
+ dvd->vdev_child[i]);
+ if (error != 0)
+ return (error);
+ }
+
+ if (svd->vdev_ops->vdev_op_leaf)
+ vdev_copy_path_impl(svd, dvd);
+
+ return (0);
+}
+
+static void
+vdev_copy_path_search(vdev_t *stvd, vdev_t *dvd)
+{
+ ASSERT(stvd->vdev_top == stvd);
+ ASSERT3U(stvd->vdev_id, ==, dvd->vdev_top->vdev_id);
+
+ for (uint64_t i = 0; i < dvd->vdev_children; i++) {
+ vdev_copy_path_search(stvd, dvd->vdev_child[i]);
+ }
+
+ if (!dvd->vdev_ops->vdev_op_leaf || !vdev_is_concrete(dvd))
+ return;
+
+ /*
+ * The idea here is that while a vdev can shift positions within
+ * a top vdev (when replacing, attaching mirror, etc.) it cannot
+ * step outside of it.
+ */
+ vdev_t *vd = vdev_lookup_by_guid(stvd, dvd->vdev_guid);
+
+ if (vd == NULL || vd->vdev_ops != dvd->vdev_ops)
+ return;
+
+ ASSERT(vd->vdev_ops->vdev_op_leaf);
+
+ vdev_copy_path_impl(vd, dvd);
+}
+
+/*
+ * Recursively copy vdev paths from one root vdev to another. Source and
+ * destination vdev trees may differ in geometry. For each destination leaf
+ * vdev, search a vdev with the same guid and top vdev id in the source.
+ * Intended to copy paths from userland config into MOS config.
+ */
+void
+vdev_copy_path_relaxed(vdev_t *srvd, vdev_t *drvd)
+{
+ uint64_t children = MIN(srvd->vdev_children, drvd->vdev_children);
+ ASSERT(srvd->vdev_ops == &vdev_root_ops);
+ ASSERT(drvd->vdev_ops == &vdev_root_ops);
+
+ for (uint64_t i = 0; i < children; i++) {
+ vdev_copy_path_search(srvd->vdev_child[i],
+ drvd->vdev_child[i]);
+ }
+}
+