Fixes and cleanup after implementation of the S3 and SSH roadmap

internal/adapters/s3/backend.go

@@ -208,9 +208,10 @@ func (b *Backend) Walk(ctx context.Context, logicalPrefix string, opts storage.W
 			} else if err != nil {
 				return err
 			}
-			return nil
-		}
-		if !storage.IsNotFound(err) {
+			if opts.Limit > 0 && visited >= opts.Limit {
+				return nil
+			}
+		} else if !storage.IsNotFound(err) {
 			return err
 		}
 	}