RunUO holds on save when using DynamicSaveStrategy

[Soteric]

Hello. RunUO is running on CentOS

$uname -a && cat /etc/issue
Linux 2.6.32-220.13.1.el6.x86_64 #1 SMP Tue Apr 17 23:56:34 BST 2012 x86_64 x86_64 x86_64 GNU/Linux
CentOS release 6.2 (Final)

When trying to perform world save the RunUO process stops responding. The last message is

Core: Using dynamic save strategy
World: Saving...

kill -QUIT gives the following thread dump

Full thread dump:

"Threadpool worker" tid=0x0x7f5a9423c700 this=0x0x7f5aa6876ea0 thread handle 0x439 state : interrupted state owns ()
  at (wrapper managed-to-native) System.IO.MonoIO.Write (intptr,byte[],int,int,System.IO.MonoIOError&) <0xffffffff>
  at System.IO.FileStream.WriteInternal (byte[],int,int) <0x0006f>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object_int_int (object,intptr,intptr,intptr) <0xffffffff>

"IO Threadpool worker" tid=0x0x7f5ab824a700 this=0x0x7f5a97070138 thread handle 0x419 state : interrupted state owns ()

"Threapool monitor" tid=0x0x7f5aba3f7700 this=0x0x7f5ac43e9270 thread handle 0x413 state : interrupted state owns ()

"Threadpool worker" tid=0x0x7f5aba160700 this=0x0x7f5ac43e9750 thread handle 0x414 state : interrupted state owns ()
  at (wrapper managed-to-native) System.Threading.Monitor.try_enter_with_atomic_var (object,int,bool&) <0xffffffff>
  at System.Threading.Monitor.TryEnter (object,int,bool&) <0x0004f>
  at System.Threading.Monitor.Enter (object,bool&) <0x00023>
  at Server.Network.NetState.OnReceive (System.IAsyncResult) <0x0019f>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object (object,intptr,intptr,intptr) <0xffffffff>

"Core Thread" tid=0x0x7f5ac43f5740 this=0x0x7f5ac43e9ea0 thread handle 0x403 state : waiting on 0x431 : Event  owns ()
  at (wrapper managed-to-native) System.Threading.WaitHandle.WaitOne_internal (System.Threading.WaitHandle,intptr,int,bool) <0xffffffff>
  at System.Threading.WaitHandle.WaitOne () <0x0006b>
  at Server.FileQueue.Flush () <0x0007f>
  at Server.SequentialFileWriter.Flush () <0x0001b>
  at Server.SequentialFileWriter.Dispose (bool) <0x00028>
  at System.IO.Stream.Close () <0x00018>
  at Server.DynamicSaveStrategy.CloseFiles () <0x0001a>
  at Server.DynamicSaveStrategy.Save (Server.SaveMetrics,bool) <0x0011b>
  at Server.World.Save (bool,bool) <0x001a9>
  at Server.Misc.AutoSave.Save (bool) <0x00083>
  at Server.Misc.AutoSave.Save () <0x0000b>
  at Server.Commands.CommandHandlers.Save_OnCommand (Server.Commands.CommandEventArgs) <0x0000b>
  at Server.Commands.CommandSystem.Handle (Server.Mobile,string,Server.Network.MessageType) <0x001c8>
  at Server.Mobile.DoSpeech (string,int[],Server.Network.MessageType,int) <0x00083>
  at Server.Mobiles.PlayerMobile.DoSpeech (string,int[],Server.Network.MessageType,int) <0x001fb>
  at Server.Network.PacketHandlers.UnicodeSpeech (Server.Network.NetState,Server.Network.PacketReader) <0x00298>
  at Server.Network.MessagePump.HandleReceive (Server.Network.NetState) <0x00563>
  at Server.Network.MessagePump.Slice () <0x000bf>
  at Server.Core.Main (string[]) <0x00d7b>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

"Timer Thread" tid=0x0x7f5ab8209700 this=0x0x7f5ac43e99c0 thread handle 0x41b state : interrupted state owns ()
  at (wrapper managed-to-native) System.Threading.WaitHandle.WaitOne_internal (System.Threading.WaitHandle,intptr,int,bool) <0xffffffff>
  at System.Threading.WaitHandle.WaitOne (int,bool) <0x00087>
  at Server.Timer/TimerThread.TimerMain () <0x002df>
  at System.Threading.Thread.StartUnsafe () <0x00071>
  at (wrapper runtime-invoke) object.runtime_invoke_void__this__ (object,intptr,intptr,intptr) <0xffffffff>

"Threadpool worker" tid=0x0x7f5a9443d700 this=0x0x7f5aa6850c30 thread handle 0x437 state : interrupted state owns ()
  at (wrapper managed-to-native) System.IO.MonoIO.Write (intptr,byte[],int,int,System.IO.MonoIOError&) <0xffffffff>
  at System.IO.FileStream.WriteInternal (byte[],int,int) <0x0006f>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object_int_int (object,intptr,intptr,intptr) <0xffffffff>

"Threadpool worker" tid=0x0x7f5a84303700 this=0x0x7f5aa68764e0 thread handle 0x43f state : interrupted state owns ()
  at (wrapper managed-to-native) System.IO.MonoIO.Write (intptr,byte[],int,int,System.IO.MonoIOError&) <0xffffffff>
  at System.IO.FileStream.WriteInternal (byte[],int,int) <0x0006f>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object_int_int (object,intptr,intptr,intptr) <0xffffffff>

"<threadpool thread>" tid=0x0x7f5ab828b700 this=0x0x7f5a97070270 thread handle 0x418 state : interrupted state owns ()

I narrowed down the problem to the following piece of code. DynamicSaveStrategy.cs, it holds on highlighted line. If I switch items and mobiles it holds on mobiles then.

		private void CloseFiles()
		{
			_itemData.Close();
			_itemIndex.Close();

			_mobileData.Close();
			_mobileIndex.Close();

			_guildData.Close();
			_guildIndex.Close();
		}

I checked FileQueue.cs Flush method where it enters the waiting state.

		public void Flush() {
			if ( buffered.buffer != null ) {
				Append( buffered );

				buffered.buffer = null;
				buffered.length = 0;
			}

			/*lock ( syncRoot ) {
				if ( pending.Count > 0 ) {
					idle.Reset();
				}

				for ( int slot = 0; slot < active.Length && pending.Count > 0; ++slot ) {
					if ( active[slot] == null ) {
						Page page = pending.Dequeue();

						active[slot] = new Chunk( this, slot, page.buffer, 0, page.length );

						++activeCount;

						callback( active[slot] );
					}
				}
			}*/

			idle.WaitOne();
		}

It seems that 'idle' should be reset in Append method or somewhere before Flush is invoked but it doesn't happen. Some additional information:
- It works on Windows with the same save strategy and the same world;
- Distro RunUO SVN works on Linux with the same save strategy but with empty world.

Any ideas would be very helpful.