.NET MVC file upload - Overlapped I/O operation is in progress

Question

I'm performing a file upload to a .NET MVC server and I seem to randomly get "Overlapped I/O operation is in progress." This happens at almost every attempt.

Based on the stack trace it never actually reaches my code so I'm not sure what's going on.

The code is fairly standard (simplified) and it actually works on some attempts.

@using (Html.BeginForm(null, null, FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="file" name="couponImage" id="couponImage" />
    <input type="submit" />
}

public async Task<ActionResult> Update(HttpPostedFileBase couponImage){
    ...
}

Here's the trace:

[COMException (0x800703e5): Overlapped I/O operation is in progress. (Exception from HRESULT: 0x800703E5)]

[HttpException (0x80004005): An error occurred while communicating with the remote host. The error code is 0x800703E5.]
   System.Web.Hosting.IIS7WorkerRequest.RaiseCommunicationError(Int32 result, Boolean throwOnDisconnect) +3417867
   System.Web.Hosting.IIS7WorkerRequest.ReadEntityCoreSync(Byte[] buffer, Int32 offset, Int32 size) +9639020
   System.Web.Hosting.IIS7WorkerRequest.ReadEntityBody(Byte[] buffer, Int32 size) +24
   System.Web.HttpRequest.GetEntireRawContent() +315
   System.Web.HttpRequest.GetMultipartContent() +63
   System.Web.HttpRequest.FillInFilesCollection() +71
   System.Web.HttpRequest.EnsureFiles() +87
   System.Web.HttpRequest.get_Files() +13
   System.Web.HttpRequestWrapper.get_Files() +28
   System.Web.Mvc.HttpFileCollectionValueProvider.GetHttpPostedFileDictionary(ControllerContext controllerContext) +52
   System.Web.Mvc.HttpFileCollectionValueProvider..ctor(ControllerContext controllerContext) +25
   System.Web.Mvc.HttpFileCollectionValueProviderFactory.GetValueProvider(ControllerContext controllerContext) +43
   System.Web.Mvc.ValueProviderFactoryCollection.GetValueProvider(ControllerContext controllerContext) +84
   System.Web.Mvc.ControllerBase.get_ValueProvider() +49
   System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor) +74
   System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor) +124
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__19(AsyncCallback asyncCallback, Object asyncState) +904
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +30
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +114
   System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag, Int32 timeout) +71
   System.Web.Mvc.Async.AsyncControllerActionInvoker.BeginInvokeAction(ControllerContext controllerContext, String actionName, AsyncCallback callback, Object state) +307
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1c(AsyncCallback asyncCallback, Object asyncState, ExecuteCoreState innerState) +46
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +43
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +114
   System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object callbackState, BeginInvokeDelegate`1 beginDelegate, EndInvokeVoidDelegate`1 endDelegate, TState invokeState, Object tag, Int32 timeout, SynchronizationContext callbackSyncContext) +83
   System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state) +362
   System.Web.Mvc.Controller.<BeginExecute>b__14(AsyncCallback asyncCallback, Object callbackState, Controller controller) +32
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +35
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +114
   System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object callbackState, BeginInvokeDelegate`1 beginDelegate, EndInvokeVoidDelegate`1 endDelegate, TState invokeState, Object tag, Int32 timeout, SynchronizationContext callbackSyncContext) +101
   System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state) +338
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state) +30
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(AsyncCallback asyncCallback, Object asyncState, ProcessRequestState innerState) +53
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +43
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +114
   System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object callbackState, BeginInvokeDelegate`1 beginDelegate, EndInvokeVoidDelegate`1 endDelegate, TState invokeState, Object tag, Int32 timeout, SynchronizationContext callbackSyncContext) +83
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +290
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +67
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +30
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +103
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

Strangely enough this was caused by an async code being run in one of the controller lifecycle override methods. The code performed database logging, not any direct file IO.

I changed the code to a synchronous version and all started working fine.