CA-110160: Fixed uncaught exception in VM migrate wizard observed while concurrent migrate operation is triggered on same VM

- before leaving each page of the wizard, check if all selected VMs are still available for migration

Signed-off-by: Mihaela Stoica <mihaela.stoica@citrix.com>

XenAdmin/Wizards/CrossPoolMigrateWizard/CrossPoolMigrateDestinationPage.cs

@@ -103,13 +103,6 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
             return filters;
         }
         
-        private void ShowWarningMessageBox(string message)
-        {
-            new ThreeButtonDialog(
-                new ThreeButtonDialog.Details(SystemIcons.Warning, message, Messages.CPM_WIZARD_TITLE)).ShowDialog(
-                    Program.MainWindow);
-        }
-
         public override void PageLeave(XenAdmin.Controls.PageLoadedDirection direction, ref bool cancel)
         {
             if (!cancel)
@@ -120,12 +113,19 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
                                    {
                                        if (Connection == null || !Connection.IsConnected)
                                        {
-                                           ShowWarningMessageBox(Messages.CPM_WIZARD_ERROR_TARGET_DISCONNECTED);
+                                           CrossPoolMigrateWizard.ShowWarningMessageBox(Messages.CPM_WIZARD_ERROR_TARGET_DISCONNECTED);
                                            targetDisconnected = true;
                                        }
                                    });
                 cancel = targetDisconnected;
             }
+
+            if (!cancel && !CrossPoolMigrateWizard.AllVMsAvailable(selectedVMs))
+            {
+                cancel = true;
+                SetButtonNextEnabled(false);
+            }
+
             base.PageLeave(direction, ref cancel);
         }
     }

XenAdmin/Wizards/CrossPoolMigrateWizard/CrossPoolMigrateNetworkingPage.cs

@@ -29,7 +29,10 @@
  * SUCH DAMAGE.
  */
 
+using System;
 using System.Collections.Generic;
+using System.Linq;
+using XenAdmin.Controls;
 using XenAdmin.Wizards.GenericPages;
 using XenAPI;
 
@@ -66,5 +69,17 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
             List<VIF> vifs = Connection.ResolveAll(vm.VIFs);
             return new CrossPoolMigrationNetworkResourceContainer(vifs);
         }
+
+        public override void PageLeave(PageLoadedDirection direction, ref bool cancel)
+        {
+            if (!CrossPoolMigrateWizard.AllVMsAvailable(VmMappings, Connection))
+            {
+                cancel = true;
+                SetButtonNextEnabled(false);
+                SetButtonPreviousEnabled(false);
+            }
+
+            base.PageLeave(direction, ref cancel);
+        }
     }
 }

XenAdmin/Wizards/CrossPoolMigrateWizard/CrossPoolMigrateStoragePage.cs

@@ -29,8 +29,10 @@
  * SUCH DAMAGE.
  */
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
+using XenAdmin.Controls;
 using XenAdmin.Wizards.GenericPages;
 using XenAPI;
 
@@ -75,9 +77,25 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
         public override StorageResourceContainer ResourceData(string sysId)
         {
             VM vm = Connection.Resolve(new XenRef<VM>(sysId));
+
+            if (vm == null)
+                return null;
+
             List<VDI> vdis = Connection.ResolveAll(vm.VBDs).Select(v => vm.Connection.Resolve(v.VDI)).ToList();
             vdis.RemoveAll(vdi => vdi == null || Connection.Resolve(vdi.SR).GetSRType(true) == SR.SRTypes.iso);
             return new CrossPoolMigrationStorageResourceContainer(vdis);
         }
+
+        public override void PageLeave(PageLoadedDirection direction, ref bool cancel)
+        {
+            if (!CrossPoolMigrateWizard.AllVMsAvailable(VmMappings, Connection))
+            {
+                cancel = true;
+                SetButtonNextEnabled(false);
+                SetButtonPreviousEnabled(false);
+            }
+
+            base.PageLeave(direction, ref cancel);
+        }
     }
 }

XenAdmin/Wizards/CrossPoolMigrateWizard/CrossPoolMigrateTransferNetworkPage.cs

@@ -31,13 +31,17 @@
 
 using System.Collections.Generic;
 using XenAdmin.Controls;
+using XenAPI;
 
 namespace XenAdmin.Wizards.CrossPoolMigrateWizard
 {
     public partial class CrossPoolMigrateTransferNetworkPage : XenTabPage
     {
-        public CrossPoolMigrateTransferNetworkPage()
+        private List<VM> selectedVMs;
+
+        public CrossPoolMigrateTransferNetworkPage(List<VM> selectedVMs)
         {
+            this.selectedVMs = selectedVMs; 
             InitializeComponent();
             InitializeCustomPageElements();
         }
@@ -49,6 +53,9 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
             networkComboBox.IncludeOnlyNetworksWithIPAddresses = true;
         }
 
+        private bool m_buttonNextEnabled;
+        private bool m_buttonPreviousEnabled;
+
         #region Base class (XenTabPage) overrides
 
         /// <summary>
@@ -74,7 +81,7 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
         public override void PageLoaded(PageLoadedDirection direction)
         {
             base.PageLoaded(direction);//call first so the page gets populated
-            OnPageUpdated();
+            SetButtonsEnabled(true);
         }
 
         public override void PopulatePage()
@@ -89,7 +96,33 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
             get { return networkComboBox.SelectedNetworkUuid; }
         }
 
+        public override bool EnableNext()
+        {
+            return m_buttonNextEnabled;
+        }
+
+        public override bool EnablePrevious()
+        {
+            return m_buttonPreviousEnabled;
+        }
+
+        public override void PageLeave(PageLoadedDirection direction, ref bool cancel)
+        {
+            if (!CrossPoolMigrateWizard.AllVMsAvailable(selectedVMs))
+            {
+                cancel = true;
+                SetButtonsEnabled(false);
+            }
+
+            base.PageLeave(direction, ref cancel);
+        }
         #endregion
 
+        protected void SetButtonsEnabled(bool enabled)
+        {
+            m_buttonNextEnabled = enabled;
+            m_buttonPreviousEnabled = enabled;
+            OnPageUpdated();
+        }
     }
 }

XenAdmin/Wizards/CrossPoolMigrateWizard/CrossPoolMigrateWizard.cs

@@ -128,7 +128,7 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
 
             m_pageStorage = new CrossPoolMigrateStoragePage();
             m_pageNetwork = new CrossPoolMigrateNetworkingPage();
-            m_pageTransferNetwork = new CrossPoolMigrateTransferNetworkPage();
+            m_pageTransferNetwork = new CrossPoolMigrateTransferNetworkPage(VmsFromSelection(selection));
             m_pageFinish = new CrossPoolMigrateFinishPage {SummaryRetreiver = GetVMMappingSummary};
             m_pageTargetRbac = new RBACWarningPage();
 
@@ -143,6 +143,12 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
 
         protected override void FinishWizard()
         {
+            if (!AllVMsAvailable(m_vmMappings, xenConnection))
+            {
+                base.FinishWizard();
+                return;
+            }
+
             foreach (KeyValuePair<string, VmMapping> pair in m_vmMappings)
             {
                 VM vm = xenConnection.Resolve(new XenRef<VM>(pair.Key));
@@ -314,5 +320,58 @@ namespace XenAdmin.Wizards.CrossPoolMigrateWizard
             }
             return summary.Details;
         }
+
+        /// <summary>
+        /// Checks if all VMs are still available for migration and shows a warning message if the check fails
+        /// </summary>
+        /// <returns>true if check succeded, false if failed</returns>
+        internal static bool AllVMsAvailable(List<VM> vms)
+        {
+            Func<bool> vmCheck = delegate
+                                     {
+                                         if (vms == null || vms.Count == 0 || vms[0] == null || vms[0].Connection == null)
+                                             return false;
+                                         var connection = vms[0].Connection; // the connection on which to check VM availability
+                                         return vms.All(vm => connection.Resolve(new XenRef<VM>(vm.opaque_ref)) != null);
+                                     };
+
+            return PerformCheck(vmCheck);
+        }
+
+        /// <summary>
+        /// Checks if all VMs are still available for migration and shows a warning message if the check fails
+        /// </summary>
+        /// <returns>true if check succeded, false if failed</returns>
+        internal static bool AllVMsAvailable(Dictionary<string, VmMapping> vmMappings, IXenConnection connection)
+        {
+            Func<bool> vmCheck = delegate
+            {
+                if (vmMappings == null || vmMappings.Count == 0 || connection == null)
+                    return false;
+                return vmMappings.All(kvp => connection.Resolve(new XenRef<VM>(kvp.Key)) != null);
+            };
+
+            return PerformCheck(vmCheck);
+        }
+
+        /// <summary>
+        /// Performs a certain check and shows a warning message if the check fails
+        /// </summary>
+        /// <param name="check">The check to perform</param>
+        /// <returns>true if check succeded, false if failed</returns>
+        private static bool PerformCheck(Func<bool> check)
+        {
+            if (check())
+                return true;
+            ShowWarningMessageBox(Messages.CPM_WIZARD_VM_MISSING_ERROR);
+            return false;
+        }
+
+        internal static void ShowWarningMessageBox(string message)
+        {
+            new ThreeButtonDialog(
+                new ThreeButtonDialog.Details(SystemIcons.Warning, message, Messages.CPM_WIZARD_TITLE)).ShowDialog(
+                    Program.MainWindow);
+        }
 	}
 }

XenAdmin/Wizards/GenericPages/SelectMultipleVMDestinationPage.cs

@@ -204,8 +204,8 @@ namespace XenAdmin.Wizards.GenericPages
         public abstract DelayLoadingOptionComboBoxItem CreateDelayLoadingOptionComboBoxItem(IXenObject xenItem);
 
 		#region Private methods
-
-        private void SetButtonNextEnabled(bool enabled)
+        
+        protected void SetButtonNextEnabled(bool enabled)
         {
             m_buttonNextEnabled = enabled;
             OnPageUpdated();

XenAdmin/Wizards/GenericPages/SelectMultipleVMNetworkPage.cs

@@ -95,15 +95,6 @@ namespace XenAdmin.Wizards.GenericPages
         public override void PageLeave(PageLoadedDirection direction, ref bool cancel)
         {
             targetConnection = null;
-
-            if (VmMappings.Select(kvp => kvp.Key).Any(sysId => NetworkData(sysId) == null))
-            {
-                ShowWarningMessageBox(Messages.CPM_WIZARD_VM_MISSING_ERROR);
-                cancel = true;
-                SetButtonNextEnabled(false);
-                SetButtonPreviousEnabled(false);
-            }
-
             base.PageLeave(direction, ref cancel);
         }
 
@@ -288,13 +279,5 @@ namespace XenAdmin.Wizards.GenericPages
 			m_dataGridView.CommitEdit(DataGridViewDataErrorContexts.Commit);
 			IsDirty = true;
 		}
-
-        private void ShowWarningMessageBox(string message)
-        {
-            new ThreeButtonDialog(
-                new ThreeButtonDialog.Details(SystemIcons.Warning, message, Messages.CPM_WIZARD_TITLE)).ShowDialog(
-                    Program.MainWindow);
-        }
-
 	}
 }

XenAdmin/Wizards/GenericPages/SelectVMStorageWithMultipleVirtualDisksPage.cs

@@ -101,6 +101,7 @@ namespace XenAdmin.Wizards.GenericPages
 		private ulong m_totalSpaceRequired;
 		private Dictionary<string, VmMapping> m_vmMappings;
         private bool m_buttonNextEnabled;
+        private bool m_buttonPreviousEnabled;
 
 		#endregion
 
@@ -142,11 +143,17 @@ namespace XenAdmin.Wizards.GenericPages
 		{
 		    TargetConnection = null;
 
-			if (direction == PageLoadedDirection.Forward && IsDirty && ImplementsIsDirty())
+			if (!cancel && direction == PageLoadedDirection.Forward && IsDirty && ImplementsIsDirty())
 					cancel = !PerformCheck(CheckStorageRequirements);
 
 			base.PageLeave(direction, ref cancel);
-		}
+        }
+
+        public override void PageLoaded(PageLoadedDirection direction)
+        {
+            base.PageLoaded(direction);//call first so the page gets populated
+            SetButtonPreviousEnabled(true);
+        }
 
 	    public abstract StorageResourceContainer ResourceData(string sysId);
 
@@ -292,6 +299,11 @@ namespace XenAdmin.Wizards.GenericPages
             return m_buttonNextEnabled;
         }
 
+        public override bool EnablePrevious()
+        {
+            return m_buttonPreviousEnabled;
+        }
+
 	    #endregion
 
 		#region Accessors
@@ -341,12 +353,18 @@ namespace XenAdmin.Wizards.GenericPages
             return success;
         }
 
-        private void SetButtonNextEnabled(bool enabled)
+        protected void SetButtonNextEnabled(bool enabled)
         {
             m_buttonNextEnabled = enabled;
             OnPageUpdated();
         }
 
+        protected void SetButtonPreviousEnabled(bool enabled)
+        {
+            m_buttonPreviousEnabled = enabled;
+            OnPageUpdated();
+        }
+
 		private bool CheckStorageRequirements(out string error)
 		{
 			error = string.Empty;

XenAdmin/Wizards/GenericPages/VMMappingSummary.cs

@@ -204,6 +204,9 @@ namespace XenAdmin.Wizards.GenericPages
             foreach (var pair in mapping.Storage)
             {
                 VDI vdi = connection.Resolve(new XenRef<VDI>(pair.Key));
+                if (vdi == null)
+                    continue;
+
                 string valueToAdd = vdi.Name + separatorText + pair.Value.Name;
 
                 if (pair.Key == mapping.Storage.First().Key)