update episode refresh

MediaBrowser.Providers/TV/TvdbEpisodeProvider.cs

@@ -112,6 +112,8 @@ namespace MediaBrowser.Providers.TV
             if (TvdbSeriesProvider.IsValidSeries(searchInfo.SeriesProviderIds) && 
 				(searchInfo.IndexNumber.HasValue || searchInfo.PremiereDate.HasValue))
             {
+                await TvdbSeriesProvider.Current.EnsureSeriesInfo(searchInfo.SeriesProviderIds, searchInfo.MetadataLanguage, cancellationToken).ConfigureAwait(false);
+
                 var seriesDataPath = TvdbSeriesProvider.GetSeriesDataPath(_config.ApplicationPaths, searchInfo.SeriesProviderIds);
 
                 var searchNumbers = new EpisodeNumbers();

MediaBrowser.Providers/TV/TvdbSeriesProvider.cs

@@ -329,7 +329,12 @@ namespace MediaBrowser.Providers.TV
             return false;
         }
 
+        private SemaphoreSlim _ensureSemaphore = new SemaphoreSlim(1,1);
         internal async Task<string> EnsureSeriesInfo(Dictionary<string, string> seriesProviderIds, string preferredMetadataLanguage, CancellationToken cancellationToken)
+        {
+            await _ensureSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+            try
             {
                 string seriesId;
                 if (seriesProviderIds.TryGetValue(MetadataProviders.Tvdb.ToString(), out seriesId))
@@ -362,6 +367,11 @@ namespace MediaBrowser.Providers.TV
 
                 return null;
             }
+            finally
+            {
+                _ensureSemaphore.Release();
+            }
+        }
 
         private bool IsCacheValid(string seriesDataPath, string preferredMetadataLanguage)
         {