diff --git a/src/fs_image.c b/src/fs_image.c
index 4a91268..1bce4d3 100644
--- a/src/fs_image.c
+++ b/src/fs_image.c
@@ -2198,9 +2198,9 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
 
     /* recursively add image */
     ret = iso_add_dir_src_rec(image, image->root, newroot);
-    
+
     /* error during recursive image addition? */
-    if (ret <= 0) {
+    if (ret < 0) {
         iso_node_builder_unref(image->builder);
         goto import_revert;
     }
@@ -2252,7 +2252,7 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
     iso_image_set_copyright_file_id(image, data->copyright_file_id);
     iso_image_set_abstract_file_id(image, data->abstract_file_id);
     iso_image_set_biblio_file_id(image, data->biblio_file_id);
-            
+
     if (features != NULL) {
         features->hasJoliet = data->joliet;
         features->hasRR = data->rr_version != 0;
diff --git a/src/tree.c b/src/tree.c
index 386a877..75a6be8 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -491,7 +491,7 @@ int check_special(IsoImage *image, mode_t mode)
  * Recursively add a given directory to the image tree.
  * 
  * @return
- *      1 continue, 0 stop, < 0 error
+ *      1 continue, < 0 error (ISO_CANCELED stop)
  */
 int iso_add_dir_src_rec(IsoImage *image, IsoDir *parent, IsoFileSource *dir)
 {
@@ -608,7 +608,7 @@ dir_rec_continue:;
     } /* while */
 
     iso_file_source_close(dir);
-    return ret;
+    return ret < 0 ? ret : ISO_SUCCESS;
 }
 
 int iso_tree_add_dir_rec(IsoImage *image, IsoDir *parent, const char *dir)