From be21e09db1dba8add010d64833e46abe1110072e Mon Sep 17 00:00:00 2001
From: Kenneth Hsu <kennethhsu@gmail.com>
Date: Fri, 22 Mar 2019 19:11:54 -0700
Subject: [PATCH] Cancel the FlushBackend task if upload exception occurs.

This should avoid the problem of something awaiting a
FlushBackend.LastWriteSizeAync task that may never complete.
---
 Duplicati/Library/Main/Operation/Backup/BackendUploader.cs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Duplicati/Library/Main/Operation/Backup/BackendUploader.cs b/Duplicati/Library/Main/Operation/Backup/BackendUploader.cs
index cf6a4c2b3..a7ed6418b 100644
--- a/Duplicati/Library/Main/Operation/Backup/BackendUploader.cs
+++ b/Duplicati/Library/Main/Operation/Backup/BackendUploader.cs
@@ -39,6 +39,12 @@ namespace Duplicati.Library.Main.Operation.Backup
     {
         public Task<long> LastWriteSizeAsync { get { return m_tcs.Task; } }
         private readonly TaskCompletionSource<long> m_tcs = new TaskCompletionSource<long>();
+        
+        public void TrySetCanceled()
+        {
+            m_tcs.TrySetCanceled();
+        }
+        
         public void SetFlushed(long size)
         {
             m_tcs.TrySetResult(size);
@@ -171,6 +177,7 @@ namespace Duplicati.Library.Main.Operation.Backup
                                 Task finishedTask = await Task.WhenAny(workers.Select(w => w.Task)).ConfigureAwait(false);
                                 if (finishedTask.IsFaulted)
                                 {
+                                    flush.TrySetCanceled();
                                     ExceptionDispatchInfo.Capture(finishedTask.Exception).Throw();
                                 }