Changed locks to prevent deadlocks (especially during multi-region Load OAR)

OpenSim/Region/CoreModules/World/Archiver/ArchiveReadRequest.cs

@@ -603,15 +603,20 @@ namespace OpenSim.Region.CoreModules.World.Archiver
         /// <param name="uuid"></param>
         /// <returns></returns>
         private bool ResolveUserUuid(Scene scene, UUID uuid)
+        {
+            lock (m_validUserUuids)
             {
                 if (!m_validUserUuids.ContainsKey(uuid))
                 {
+                    // Note: we call GetUserAccount() inside the lock because this UserID is likely
+                    // to occur many times, and we only want to query the users service once.
                     UserAccount account = scene.UserAccountService.GetUserAccount(scene.RegionInfo.ScopeID, uuid);
                     m_validUserUuids.Add(uuid, account != null);
                 }
 
                 return m_validUserUuids[uuid];
             }
+        }
 
         /// <summary>
         /// Look up the given group id to check whether it's one that is valid for this grid.
@@ -623,20 +628,27 @@ namespace OpenSim.Region.CoreModules.World.Archiver
             if (uuid == UUID.Zero)
                 return true;    // this means the object has no group
 
+            lock (m_validGroupUuids)
+            {
                 if (!m_validGroupUuids.ContainsKey(uuid))
                 {
                     bool exists;
-                
                     if (m_groupsModule == null)
+                    {
                         exists = false;
+                    }
                     else
+                    {
+                        // Note: we call GetGroupRecord() inside the lock because this GroupID is likely
+                        // to occur many times, and we only want to query the groups service once.
                         exists = (m_groupsModule.GetGroupRecord(uuid) != null);
-
+                    }
                     m_validGroupUuids.Add(uuid, exists);
                 }
 
                 return m_validGroupUuids[uuid];
             }
+        }
 
         /// Load an asset
         /// </summary>

OpenSim/Region/CoreModules/World/Land/LandManagementModule.cs

@@ -287,14 +287,15 @@ namespace OpenSim.Region.CoreModules.World.Land
             LandData newData = data.Copy();
             newData.LocalID = local_id;
 
+            ILandObject land;
             lock (m_landList)
             {
-                if (m_landList.ContainsKey(local_id))
-                {
-                    m_landList[local_id].LandData = newData;
-                    m_scene.EventManager.TriggerLandObjectUpdated((uint)local_id, m_landList[local_id]);
-                }
+                if (m_landList.TryGetValue(local_id, out land))
+                    land.LandData = newData;
             }
+
+            if (land != null)
+                m_scene.EventManager.TriggerLandObjectUpdated((uint)local_id, land);
         }
 
         public bool AllowedForcefulBans
@@ -650,6 +651,7 @@ namespace OpenSim.Region.CoreModules.World.Land
         /// <param name="local_id">Land.localID of the peice of land to remove.</param>
         public void removeLandObject(int local_id)
         {
+            ILandObject land;
             lock (m_landList)
             {
                 for (int x = 0; x < 64; x++)
@@ -666,9 +668,11 @@ namespace OpenSim.Region.CoreModules.World.Land
                     }
                 }
 
-                m_scene.EventManager.TriggerLandObjectRemoved(m_landList[local_id].LandData.GlobalID);
+                land = m_landList[local_id];
                 m_landList.Remove(local_id);
             }
+
+            m_scene.EventManager.TriggerLandObjectRemoved(land.LandData.GlobalID);
         }
         
         /// <summary>
@@ -676,22 +680,28 @@ namespace OpenSim.Region.CoreModules.World.Land
         /// </summary>        
         public void Clear(bool setupDefaultParcel)
         {
+            List<ILandObject> parcels;
             lock (m_landList)
             {
-                foreach (ILandObject lo in m_landList.Values)
+                parcels = new List<ILandObject>(m_landList.Values);
+            }
+
+            foreach (ILandObject lo in parcels)
             {
                 //m_scene.SimulationDataService.RemoveLandObject(lo.LandData.GlobalID);
                 m_scene.EventManager.TriggerLandObjectRemoved(lo.LandData.GlobalID);
             }
 
+            lock (m_landList)
+            {
                 m_landList.Clear();
 
                 ResetSimLandObjects();
+            }
             
             if (setupDefaultParcel)
                 CreateDefaultParcel();
         }
-        }
 
         private void performFinalLandJoin(ILandObject master, ILandObject slave)
         {
@@ -1457,13 +1467,10 @@ namespace OpenSim.Region.CoreModules.World.Land
         }
 
         public void EventManagerOnNoLandDataFromStorage()
-        {
-            lock (m_landList)
         {
             ResetSimLandObjects();
             CreateDefaultParcel();
         }
-        }
 
         #endregion
 

OpenSim/Region/CoreModules/World/Land/PrimCountModule.cs

@@ -490,12 +490,15 @@ namespace OpenSim.Region.CoreModules.World.Land
 
             m_Scene.ForEachSOG(AddObject);
 
+            lock (m_PrimCounts)
+            {
                 List<UUID> primcountKeys = new List<UUID>(m_PrimCounts.Keys);
                 foreach (UUID k in primcountKeys)
                 {
                     if (!m_OwnerMap.ContainsKey(k))
                         m_PrimCounts.Remove(k);
                 }
+            }
             
             m_Tainted = false;
         }