Avoid concurrent git calls

Author: craflin

src/Worker.cpp

@@ -383,6 +383,8 @@ void Worker::handleGetRequest(const String& repoUrl, const String& repo, const S
 
     // info response
     {
+        NamedMutexGuard guard(cacheDir);
+
         String command = String("git-upload-pack --stateless-rpc --advertise-refs \"") + cacheDir + "\"";
         Log::infof("%s", (const char*)command);
         Process process;
@@ -423,6 +425,8 @@ void Worker::handlePostRequest(const String& repo, const String& auth, Buffer& b
     String cacheDir = _settings.cacheDir + "/" + repo;
 
     {
+        NamedMutexGuard guard(cacheDir);
+
         String command = String("git-upload-pack --stateless-rpc \"") + cacheDir + "\"";
         Log::infof("%s", (const char*)command);
         Process process;