1 files changed, 36 insertions, 3 deletions
diff --git a/Emby.Server.Implementations/IO/LibraryMonitor.cs b/Emby.Server.Implementations/IO/LibraryMonitor.cs
index 1bf0f8c76c..e51c863f86 100644
--- a/Emby.Server.Implementations/IO/LibraryMonitor.cs
+++ b/Emby.Server.Implementations/IO/LibraryMonitor.cs
@@ -3,11 +3,13 @@ using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Emby.Server.Implementations.Library;
 using MediaBrowser.Controller.Configuration;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
+using MediaBrowser.Controller.Providers;
 using MediaBrowser.Model.IO;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -21,6 +23,7 @@ namespace Emby.Server.Implementations.IO
         private readonly ILibraryManager _libraryManager;
         private readonly IServerConfigurationManager _configurationManager;
         private readonly IFileSystem _fileSystem;
+        private readonly IDirectoryService _directoryService;
         private readonly DotIgnoreIgnoreRule _dotIgnoreIgnoreRule;
 
         /// <summary>
@@ -38,6 +41,12 @@ namespace Emby.Server.Implementations.IO
         /// </summary>
         private readonly ConcurrentDictionary<string, string> _tempIgnoredPaths = new(StringComparer.OrdinalIgnoreCase);
 
+        /// <summary>
+        /// Incremented by every <see cref="Stop"/> so watchers still being created on a background
+        /// task can tell that the sweep they should have been caught by has already run.
+        /// </summary>
+        private int _watcherGeneration;
+
         private bool _disposed;
 
         /// <summary>
@@ -47,6 +56,7 @@ namespace Emby.Server.Implementations.IO
         /// <param name="libraryManager">The library manager.</param>
         /// <param name="configurationManager">The configuration manager.</param>
         /// <param name="fileSystem">The filesystem.</param>
+        /// <param name="directoryService">The directory service.</param>
         /// <param name="appLifetime">The <see cref="IHostApplicationLifetime"/>.</param>
         /// <param name="dotIgnoreIgnoreRule">The .ignore rule handler.</param>
         public LibraryMonitor(
@@ -54,6 +64,7 @@ namespace Emby.Server.Implementations.IO
             ILibraryManager libraryManager,
             IServerConfigurationManager configurationManager,
             IFileSystem fileSystem,
+            IDirectoryService directoryService,
             IHostApplicationLifetime appLifetime,
             DotIgnoreIgnoreRule dotIgnoreIgnoreRule)
         {
@@ -61,10 +72,11 @@ namespace Emby.Server.Implementations.IO
             _logger = logger;
             _configurationManager = configurationManager;
             _fileSystem = fileSystem;
+            _directoryService = directoryService;
             _dotIgnoreIgnoreRule = dotIgnoreIgnoreRule;
 
             appLifetime.ApplicationStarted.Register(Start);
-            appLifetime.ApplicationStopping.Register(Stop);
+            appLifetime.ApplicationStopping.Register(Dispose);
         }
 
         /// <inheritdoc />
@@ -115,6 +127,11 @@ namespace Emby.Server.Implementations.IO
         /// <inheritdoc />
         public void Start()
         {
+            if (_disposed)
+            {
+                return;
+            }
+
             _libraryManager.ItemAdded += OnLibraryManagerItemAdded;
             _libraryManager.ItemRemoved += OnLibraryManagerItemRemoved;
 
@@ -228,6 +245,8 @@ namespace Emby.Server.Implementations.IO
                 return;
             }
 
+            var generation = Volatile.Read(ref _watcherGeneration);
+
             // Creating a FileSystemWatcher over the LAN can take hundreds of milliseconds, so wrap it in a Task to do them all in parallel
             Task.Run(() =>
             {
@@ -251,7 +270,11 @@ namespace Emby.Server.Implementations.IO
                     newWatcher.Changed += OnWatcherChanged;
                     newWatcher.Error += OnWatcherError;
 
-                    if (_fileSystemWatchers.TryAdd(path, newWatcher))
+                    if (_disposed || Volatile.Read(ref _watcherGeneration) != generation)
+                    {
+                        DisposeWatcher(newWatcher, false);
+                    }
+                    else if (_fileSystemWatchers.TryAdd(path, newWatcher))
                     {
                         newWatcher.EnableRaisingEvents = true;
                         _logger.LogInformation("Watching directory {Path}", path);
@@ -352,6 +375,11 @@ namespace Emby.Server.Implementations.IO
         {
             ArgumentException.ThrowIfNullOrEmpty(path);
 
+            if (_disposed)
+            {
+                return;
+            }
+
             if (IgnorePatterns.ShouldIgnore(path))
             {
                 return;
@@ -363,6 +391,8 @@ namespace Emby.Server.Implementations.IO
                 return;
             }
 
+            _directoryService.Invalidate(path);
+
             // Ignore certain files, If the parent of an ignored path has a change event, ignore that too
             foreach (var i in _tempIgnoredPaths.Keys)
             {
@@ -445,6 +475,8 @@ namespace Emby.Server.Implementations.IO
         /// </summary>
         public void Stop()
         {
+            Interlocked.Increment(ref _watcherGeneration);
+
             _libraryManager.ItemAdded -= OnLibraryManagerItemAdded;
             _libraryManager.ItemRemoved -= OnLibraryManagerItemRemoved;
 
@@ -489,8 +521,9 @@ namespace Emby.Server.Implementations.IO
                 return;
             }
 
-            Stop();
+            // Set before stopping so anything racing us stops handing out new work.
             _disposed = true;
+            Stop();
         }
     }
 }