From 4e5d015e0cce2691ac44cfef8ef85dd1a290fc01 Mon Sep 17 00:00:00 2001
From: Carl Johnsen <carl-johannes@di.ku.dk>
Date: Tue, 28 Oct 2025 14:41:58 +0100
Subject: [PATCH] Added the deadlock timer task

---
 .../Main/Operation/Restore/DeadlockTimer.cs   | 100 ++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 Duplicati/Library/Main/Operation/Restore/DeadlockTimer.cs

diff --git a/Duplicati/Library/Main/Operation/Restore/DeadlockTimer.cs b/Duplicati/Library/Main/Operation/Restore/DeadlockTimer.cs
new file mode 100644
index 000000000..fa46e8de6
--- /dev/null
+++ b/Duplicati/Library/Main/Operation/Restore/DeadlockTimer.cs
@@ -0,0 +1,100 @@
+// Copyright (C) 2025, The Duplicati Team
+// https://duplicati.com, hello@duplicati.com
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+#nullable enable
+
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Duplicati.Library.Main.Operation.Restore
+{
+    /// <summary>
+    /// Class for keeping track of the maximum processing time of a block
+    /// request making a roundtrip to/from the BlockManager.
+    ///
+    /// The times are not Interlocked as reads and writes are atomic for int
+    /// types and exact accuracy is not required.
+    ///
+    /// https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/variables#96-atomicity-of-variable-references
+    ///
+    /// The worst case is that the reads are stale by one update, which is
+    /// acceptable for this use case. The same applies to the MaxProcessingTime
+    /// property, which means that the BlockManager may use a slightly stale
+    /// value when checking for timeouts, which is also acceptable.
+    /// </summary>
+    internal class DeadlockTimer
+    {
+        /// <summary>
+        /// The log tag for this class.
+        /// </summary>
+        private static readonly string LOGTAG =
+            Logging.Log.LogTagFromType<DeadlockTimer>();
+        /// <summary>
+        /// Five minutes in milliseconds.
+        /// </summary>
+        private static readonly int five_minutes_ms = (int)TimeSpan.FromMinutes(5).TotalMilliseconds;
+        /// <summary>
+        /// Cancellation token for stopping the deadlock timer.
+        /// </summary>
+        public static CancellationTokenSource Token = new();
+        /// <summary>
+        /// Maximum processing time (in milliseconds) recorded for any block
+        /// request.
+        /// </summary>
+        public static int MaxProcessingTime = five_minutes_ms;
+
+        /// <summary>
+        /// Runs the deadlock timer process. It runs every second and updates
+        /// the maximum processing time based on the maximum processing times
+        /// of the active VolumeDownloaders, VolumeDecryptors and
+        /// VolumeDecompressors.
+        /// </summary>
+        /// <remarks>It will keep running until the cancellation token
+        /// `DeadlockTimer.token` is cancelled.</remarks>
+        /// <returns>An awaitable task.</returns>
+        public static async Task Run()
+        {
+            try
+            {
+                while (!Token.IsCancellationRequested)
+                {
+                    await Task.Delay(TimeSpan.FromSeconds(1), Token.Token)
+                        .ConfigureAwait(false);
+
+                    int download = VolumeDownloader.MaxProcessingTimes.Max();
+                    int decrypt = VolumeDecryptor.MaxProcessingTimes.Max();
+                    int decompress = VolumeDecompressor.MaxProcessingTimes.Max();
+
+                    MaxProcessingTime = Math.Max(
+                        five_minutes_ms,
+                        (download + decrypt + decompress) * 2
+                    );
+                }
+            }
+            catch (TaskCanceledException)
+            {
+                // Ignore
+            }
+        }
+    }
+}
\ No newline at end of file