Fix error message on promoting encrypted dataset

This patch corrects the error message reported when attempting
to promote a dataset outside of its encryption root.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8905 
Closes #8935

lib/libzfs/libzfs_dataset.c

@@ -4160,6 +4160,16 @@ zfs_promote(zfs_handle_t *zhp)
 
 	if (ret != 0) {
 		switch (ret) {
+		case EACCES:
+			/*
+			 * Promoting encrypted dataset outside its
+			 * encryption root.
+			 */
+			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+			    "cannot promote dataset outside its "
+			    "encryption root"));
+			return (zfs_error(hdl, EZFS_EXISTS, errbuf));
+
 		case EEXIST:
 			/* There is a conflicting snapshot name. */
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,

module/zfs/dsl_crypt.c

@@ -1676,11 +1676,15 @@ dsl_dataset_promote_crypt_check(dsl_dir_t *target, dsl_dir_t *origin)
 	 * Check that the parent of the target has the same encryption root.
 	 */
 	ret = dsl_dir_get_encryption_root_ddobj(origin->dd_parent, &op_rddobj);
-	if (ret != 0)
+	if (ret == ENOENT)
+		return (SET_ERROR(EACCES));
+	else if (ret != 0)
 		return (ret);
 
 	ret = dsl_dir_get_encryption_root_ddobj(target->dd_parent, &tp_rddobj);
-	if (ret != 0)
+	if (ret == ENOENT)
+		return (SET_ERROR(EACCES));
+	else if (ret != 0)
 		return (ret);
 
 	if (op_rddobj != tp_rddobj)