Fixed some concurrency/race conditions during node failure (WIP?)

mnunberg · Sep 25, 2012 · f2b161a · f2b161a
1 parent 96fbece
commit f2b161a
Showing 1 changed file with 46 additions and 21 deletions.
diff --git a/Enyim.Caching/Memcached/MemcachedNode.cs b/Enyim.Caching/Memcached/MemcachedNode.cs
@@ -139,6 +139,33 @@ public IPooledSocketResult Acquire()
 				return result;
 			}
 		}
+		/// <summary>
+		/// Tries to perform any actions on failure. Returns true if the policy
+		/// indicates that we should fail this node
+		/// </summary>
+		/// <returns></returns>
+		private bool TryToFail()
+		{
+
+			bool shouldFail;
+			if (failurePolicy != null)
+			{
+				shouldFail = failurePolicy.ShouldFail();
+			}
+			else
+			{
+				shouldFail = true;
+			}
+
+			if (!shouldFail)
+			{
+				return false;
+			}
+			if (Failed != null) {
+				Failed(this);
+			}
+			return true;
+        }
 
 		~MemcachedNode()
 		{
@@ -375,23 +402,15 @@ public IPooledSocketResult Acquire()
 			private void MarkAsDead()
 			{
 				if (log.IsDebugEnabled) log.DebugFormat("Mark as dead was requested for {0}", this.endPoint);
-
+				if (ownerNode == null || ownerNode.TryToFail() == false)
-				var shouldFail = ownerNode.FailurePolicy.ShouldFail();
-
-				if (log.IsDebugEnabled) log.Debug("FailurePolicy.ShouldFail(): " + shouldFail);
-
-				if (shouldFail)
 				{
-					if (log.IsWarnEnabled) log.WarnFormat("Marking node {0} as dead", this.endPoint);
+					return;
-
+				}
-					this.isAlive = false;
-					this.markedAsDeadUtc = DateTime.UtcNow;
 
-					var f = this.ownerNode.Failed;
+				if (log.IsWarnEnabled) log.WarnFormat("Marking node {0} as dead", this.endPoint);
 
-					if (f != null)
+				this.isAlive = false;
-						f(this.ownerNode);
+				this.markedAsDeadUtc = DateTime.UtcNow;
-				}
 			}
 
 			/// <summary>
@@ -413,9 +432,6 @@ private void ReleaseSocket(PooledSocket socket)
 					{
 						// mark the item as free
 						this.freeItems.Push(socket);
-
-						// signal the event so if someone is waiting for it can reuse this item
-						this.semaphore.Release();
 					}
 					else
 					{
@@ -424,10 +440,6 @@ private void ReleaseSocket(PooledSocket socket)
 
 						// mark ourselves as not working for a while
 						this.MarkAsDead();
-
-						// make sure to signal the Acquire so it can create a new conenction
-						// if the failure policy keeps the pool alive
-						this.semaphore.Release();
 					}
 				}
 				else
@@ -436,6 +448,19 @@ private void ReleaseSocket(PooledSocket socket)
 					// are dead. so, kill the socket (this will eventually clear the pool as well)
 					socket.Destroy();
 				}
+
+				// In any event, we want to let any waiters know that we can create a new
+				// socket:
+				if (semaphore != null)
+				{
+					try
+					{
+						semaphore.Release();
+					}
+					catch (ObjectDisposedException)
+					{
+					}
+				}
 			}