Correctly handle missing layer upload

Because we guarded the error check, nil Upload on the handler was getting
through to unexpected branches. This directly handles the missing upload
ensuring its set as expected.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

registry/layerupload.go

@@ -53,13 +53,20 @@ func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 
 		layers := ctx.services.Layers()
 		upload, err := layers.Resume(luh.Name, luh.UUID)
-		if err != nil && err != storage.ErrLayerUploadUnknown {
+		if err != nil {
-			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			ctx.log.Errorf("error resolving upload: %v", err)
-				w.WriteHeader(http.StatusBadRequest)
+			if err == storage.ErrLayerUploadUnknown {
+				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					w.WriteHeader(http.StatusNotFound)
 					luh.Errors.Push(v2.ErrorCodeBlobUploadUnknown, err)
 				})
 			}
+
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusInternalServerError)
+				luh.Errors.Push(v2.ErrorCodeUnknown, err)
+			})
+		}
 		luh.Upload = upload
 
 		if state.Offset > 0 {
@@ -68,6 +75,7 @@ func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 			// problems. We basically cancel the upload and tell the client to
 			// start over.
 			if nn, err := upload.Seek(luh.State.Offset, os.SEEK_SET); err != nil {
+				defer upload.Close()
 				ctx.log.Infof("error seeking layer upload: %v", err)
 				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusBadRequest)
@@ -75,6 +83,7 @@ func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 					upload.Cancel()
 				})
 			} else if nn != luh.State.Offset {
+				defer upload.Close()
 				ctx.log.Infof("seek to wrong offest: %d != %d", nn, luh.State.Offset)
 				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusBadRequest)
@@ -129,6 +138,7 @@ func (luh *layerUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Re
 	if luh.Upload == nil {
 		w.WriteHeader(http.StatusNotFound)
 		luh.Errors.Push(v2.ErrorCodeBlobUploadUnknown)
+		return
 	}
 
 	if err := luh.layerUploadResponse(w, r); err != nil {