diff --git a/client/cmd/swarming/lib/common.go b/client/cmd/swarming/lib/common.go
index <HASH>..<HASH> 100644
--- a/client/cmd/swarming/lib/common.go
+++ b/client/cmd/swarming/lib/common.go
@@ -176,7 +176,7 @@ func (s *swarmingServiceImpl) GetTaskOutputs(ctx context.Context, taskID, output
 		return nil, errors.Annotate(err, "failed to remove directory: %s", dir).Err()
 	}
 
-	if err := os.Mkdir(dir, os.ModePerm); err != nil {
+	if err := os.MkdirAll(dir, os.ModePerm); err != nil {
 		return nil, err
 	}
[swarming] create output directory if not exists

I think it is useful if directory is created automatically.

Change-Id: Ie<I>d<I>b9e<I>dfede<I>a<I>bc<I>ba<I>b2d<I>
Reviewed-on: <URL>