Review fixes

src/Umbraco.Core/Exceptions/LockTimeoutException.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Umbraco.Core.Exceptions
+{
+    /// <summary>
+    /// An exception that is thrown if the a query as waited for the lock too long
+    /// </summary>
+    public class LockTimeoutException : Exception
+    {
+        public LockTimeoutException(Exception inner)
+            : base(string.Empty, inner)
+        { }
+
+        public short Reason { get; set; }
+    }
+}

src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs

@@ -6,6 +6,7 @@ using Umbraco.Core.Migrations.Upgrade.Common;
 using Umbraco.Core.Migrations.Upgrade.V_8_0_0;
 using Umbraco.Core.Migrations.Upgrade.V_8_0_1;
 using Umbraco.Core.Migrations.Upgrade.V_8_1_0;
+using Umbraco.Core.Migrations.Upgrade.V_8_2_0;
 
 namespace Umbraco.Core.Migrations.Upgrade
 {
@@ -182,6 +183,8 @@ namespace Umbraco.Core.Migrations.Upgrade
             To<RenameUserLoginDtoDateIndex>("{0372A42B-DECF-498D-B4D1-6379E907EB94}");
             To<FixContentNuCascade>("{5B1E0D93-F5A3-449B-84BA-65366B84E2D4}");
 
+            // to 8.2.0....
+            To<AddLockTableColumns>("{8DC6A949-0FE4-4846-9C1D-61E49DDADFF9}");
             //FINAL
         }
     }

src/Umbraco.Core/Migrations/Upgrade/V_8_2_0/AddLockTableColumns.cs

@@ -0,0 +1,19 @@
+using System.Linq;
+using Umbraco.Core.Persistence.Dtos;
+
+namespace Umbraco.Core.Migrations.Upgrade.V_8_2_0
+{
+    public class AddLockTableColumns : MigrationBase
+    {
+        public AddLockTableColumns(IMigrationContext context)
+            : base(context)
+        { }
+
+        public override void Migrate()
+        {
+            var columns = SqlSyntax.GetColumnsInSchema(Context.Database).ToList();
+
+            AddColumnIfNotExists<LockDto>(columns, "writeLockReasonId");
+        }
+    }
+}

src/Umbraco.Core/Models/UserExtensions.cs

@@ -56,7 +56,7 @@ namespace Umbraco.Core.Models
         /// </returns>
         internal static string[] GetUserAvatarUrls(this IUser user, IAppCache cache)
         {
-            // If FIPS is required, never check the Gravatar service as it only supports MD5 hashing.  
+            // If FIPS is required, never check the Gravatar service as it only supports MD5 hashing.
             // Unfortunately, if the FIPS setting is enabled on Windows, using MD5 will throw an exception
             // and the website will not run.
             // Also, check if the user has explicitly removed all avatars including a Gravatar, this will be possible and the value will be "none"
@@ -310,6 +310,7 @@ namespace Umbraco.Core.Models
             // assume groupSn and userSn each don't contain duplicates
 
             var asn = groupSn.Concat(userSn).Distinct().ToArray();
+
             var paths = asn.Length > 0
                 ? entityService.GetAllPaths(objectType, asn).ToDictionary(x => x.Id, x => x.Path)
                 : new Dictionary<int, string>();

src/Umbraco.Core/Persistence/Constants-Locks.cs

@@ -1,62 +1,76 @@
 // ReSharper disable once CheckNamespace
+
 namespace Umbraco.Core
 {
     static partial class Constants
     {
         /// <summary>
-        /// Defines lock objects.
+        ///     Defines lock objects.
         /// </summary>
         public static class Locks
         {
             /// <summary>
-            /// All servers.
+            ///     All servers.
             /// </summary>
             public const int Servers = -331;
 
             /// <summary>
-            /// All content and media types.
+            ///     All content and media types.
             /// </summary>
             public const int ContentTypes = -332;
 
             /// <summary>
-            /// The entire content tree, i.e. all content items.
+            ///     The entire content tree, i.e. all content items.
             /// </summary>
             public const int ContentTree = -333;
 
             /// <summary>
-            /// The entire media tree, i.e. all media items.
+            ///     The entire media tree, i.e. all media items.
             /// </summary>
             public const int MediaTree = -334;
 
             /// <summary>
-            /// The entire member tree, i.e. all members.
+            ///     The entire member tree, i.e. all members.
             /// </summary>
             public const int MemberTree = -335;
 
             /// <summary>
-            /// All media types.
+            ///     All media types.
             /// </summary>
             public const int MediaTypes = -336;
 
             /// <summary>
-            /// All member types.
+            ///     All member types.
             /// </summary>
             public const int MemberTypes = -337;
 
             /// <summary>
-            /// All domains.
+            ///     All domains.
             /// </summary>
             public const int Domains = -338;
 
             /// <summary>
-            /// All key-values.
+            ///     All key-values.
             /// </summary>
             public const int KeyValues = -339;
 
             /// <summary>
-            /// All languages.
+            ///     All languages.
             /// </summary>
             public const int Languages = -340;
+
+            public static class Reason
+            {
+
+                public const short Default = 1;
+                public const short MoveContentToRecycleBin = 10000;
+                public const short RestoreContentFromRecycleBin = 10001;
+                public const short EmptyRecycleBin = 10002;
+                public const short MoveContent = 10003;
+                public const short CopyContent = 10004;
+                public const short SortContent = 10005;
+                public const short DeleteContentOfTypes = 10006;
+            }
         }
     }
 }

src/Umbraco.Core/Persistence/DatabasenodeLockExtensions.cs

@@ -1,43 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Data;
-using System.Runtime.CompilerServices;
-
-namespace Umbraco.Core.Persistence
-{
-    internal static class DatabaseNodeLockExtensions
-    {
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static void ValidateDatabase(IUmbracoDatabase database)
-        {
-            if (database == null)
-                throw new ArgumentNullException("database");
-            if (database.GetCurrentTransactionIsolationLevel() < IsolationLevel.RepeatableRead)
-                throw new InvalidOperationException("A transaction with minimum RepeatableRead isolation level is required.");
-        }
-
-        // updating a record within a repeatable-read transaction gets an exclusive lock on
-        // that record which will be kept until the transaction is ended, effectively locking
-        // out all other accesses to that record - thus obtaining an exclusive lock over the
-        // protected resources.
-        public static void AcquireLockNodeWriteLock(this IUmbracoDatabase database, int nodeId)
-        {
-            ValidateDatabase(database);
-
-            database.Execute("UPDATE umbracoLock SET value = (CASE WHEN (value=1) THEN -1 ELSE 1 END) WHERE id=@id",
-                new { @id = nodeId });
-        }
-
-        // reading a record within a repeatable-read transaction gets a shared lock on
-        // that record which will be kept until the transaction is ended, effectively preventing
-        // other write accesses to that record - thus obtaining a shared lock over the protected
-        // resources.
-        public static void AcquireLockNodeReadLock(this IUmbracoDatabase database, int nodeId)
-        {
-            ValidateDatabase(database);
-
-            database.ExecuteScalar<int>("SELECT value FROM umbracoLock WHERE id=@id",
-                new { @id = nodeId });
-        }
-    }
-}

src/Umbraco.Core/Persistence/Dtos/LockDto.cs

@@ -20,5 +20,9 @@ namespace Umbraco.Core.Persistence.Dtos
         [NullSetting(NullSetting = NullSettings.NotNull)]
         [Length(64)]
         public string Name { get; set; }
+
+        [Column("writeLockReasonId")]
+        [NullSetting(NullSetting = NullSettings.Null)]
+        public short WriteLockReasonId { get; set; }
     }
 }

src/Umbraco.Core/Persistence/ISqlContext.cs

@@ -1,4 +1,5 @@
-using NPoco;
+using System.Data;
+using NPoco;
 using Umbraco.Core.Persistence.Mappers;
 using Umbraco.Core.Persistence.Querying;
 using Umbraco.Core.Persistence.SqlSyntax;

src/Umbraco.Core/Persistence/Interceptors/LockTimeoutInterceptor.cs

@@ -0,0 +1,18 @@
+using System;
+using NPoco;
+using Umbraco.Core.Exceptions;
+
+namespace Umbraco.Core.Persistence.Interceptors
+{
+    public class LockTimeoutInterceptor : IExceptionInterceptor
+    {
+        public void OnException(IDatabase database, Exception exception)
+        {
+            if (database is IUmbracoDatabase umbracoDatabase && umbracoDatabase.SqlContext.SqlSyntax.IsLockTimeoutException(exception))
+            {
+                throw new LockTimeoutException(exception);
+            }
+
+        }
+    }
+}

src/Umbraco.Core/Persistence/SqlSyntax/ISqlSyntaxProvider.cs

@@ -5,6 +5,7 @@ using NPoco;
 using Umbraco.Core.Persistence.DatabaseAnnotations;
 using Umbraco.Core.Persistence.DatabaseModelDefinitions;
 using Umbraco.Core.Persistence.Querying;
+using IsolationLevel = System.Data.IsolationLevel;
 
 namespace Umbraco.Core.Persistence.SqlSyntax
 {
@@ -76,6 +77,8 @@ namespace Umbraco.Core.Persistence.SqlSyntax
         string ConvertIntegerToOrderableString { get; }
         string ConvertDateToOrderableString { get; }
         string ConvertDecimalToOrderableString { get; }
+        bool IsReadUncommittedSupported { get; }
+        IsolationLevel DefaultIsolationLevel { get; }
 
         IEnumerable<string> GetTablesInSchema(IDatabase db);
         IEnumerable<ColumnInfo> GetColumnsInSchema(IDatabase db);
@@ -121,5 +124,9 @@ namespace Umbraco.Core.Persistence.SqlSyntax
         /// unspecified.</para>
         /// </remarks>
         bool TryGetDefaultConstraint(IDatabase db, string tableName, string columnName, out string constraintName);
+
+        void ReadLock(IDatabase db, params int[] lockIds);
+        void WriteLock(IDatabase db, int? writeLockReasonId, params int[] lockIds);
+        bool IsLockTimeoutException(Exception exception);
     }
 }

src/Umbraco.Core/Persistence/SqlSyntax/SqlCeSyntaxProvider.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
+using System.Data.SqlServerCe;
 using System.Linq;
+using System.Transactions;
 using NPoco;
 using Umbraco.Core.Persistence.DatabaseAnnotations;
 using Umbraco.Core.Persistence.DatabaseModelDefinitions;
@@ -12,11 +14,13 @@ namespace Umbraco.Core.Persistence.SqlSyntax
     /// </summary>
     public class SqlCeSyntaxProvider : MicrosoftSqlSyntaxProviderBase<SqlCeSyntaxProvider>
     {
+
         public override Sql<ISqlContext> SelectTop(Sql<ISqlContext> sql, int top)
         {
             return new Sql<ISqlContext>(sql.SqlContext, sql.SQL.Insert(sql.SQL.IndexOf(' '), " TOP " + top), sql.Arguments);
         }
 
+
         public override bool SupportsClustered()
         {
             return false;
@@ -47,6 +51,9 @@ namespace Umbraco.Core.Persistence.SqlSyntax
             return indexType;
         }
 
+        public override bool IsReadUncommittedSupported => false;
+        public override System.Data.IsolationLevel DefaultIsolationLevel => System.Data.IsolationLevel.RepeatableRead;
+
         public override string GetConcat(params string[] args)
         {
             return "(" + string.Join("+", args) + ")";
@@ -143,6 +150,45 @@ where table_name=@0 and column_name=@1", tableName, columnName).FirstOrDefault()
             return hasDefault;
         }
 
+        public override void WriteLock(IDatabase db, int? writeLockReasonId, params int[] lockIds)
+        {
+            // soon as we get Database, a transaction is started
+
+            if (db.Transaction.IsolationLevel < (System.Data.IsolationLevel) IsolationLevel.RepeatableRead)
+                throw new InvalidOperationException("A transaction with minimum RepeatableRead isolation level is required.");
+
+            db.Execute(@"SET LOCK_TIMEOUT 1800;");
+            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
+            foreach (var lockId in lockIds)
+            {
+
+                var i = db.Execute(@"UPDATE umbracoLock SET value = value*-1, writeLockReasonId = @writeLockReasonId WHERE id=@id", new { id = lockId, writeLockReasonId = writeLockReasonId });
+                if (i == 0) // ensure we are actually locking!
+                    throw new Exception($"LockObject with id={lockId} does not exist.");
+            }
+        }
+
+        public override bool IsLockTimeoutException(Exception exception)
+        {
+            return exception is SqlCeLockTimeoutException;
+        }
+
+        public override void ReadLock(IDatabase db, params int[] lockIds)
+        {
+            // soon as we get Database, a transaction is started
+
+            if (db.Transaction.IsolationLevel < (System.Data.IsolationLevel) IsolationLevel.RepeatableRead)
+                throw new InvalidOperationException("A transaction with minimum RepeatableRead isolation level is required.");
+
+            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
+            foreach (var lockId in lockIds)
+            {
+                var i = db.ExecuteScalar<int?>("SELECT value FROM umbracoLock WHERE id=@id", new { id = lockId });
+                if (i == null) // ensure we are actually locking!
+                    throw new Exception($"LockObject with id={lockId} does not exist.");
+            }
+        }
+
         public override bool DoesTableExist(IDatabase db, string tableName)
         {
             var result =

src/Umbraco.Core/Persistence/SqlSyntax/SqlServerSyntaxProvider.cs

@@ -2,11 +2,12 @@
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
+using System.Data.SqlClient;
 using System.Linq;
 using NPoco;
 using Umbraco.Core.Logging;
 using Umbraco.Core.Persistence.DatabaseModelDefinitions;
-using Umbraco.Core.Scoping;
+
 
 namespace Umbraco.Core.Persistence.SqlSyntax
 {
@@ -173,6 +174,9 @@ namespace Umbraco.Core.Persistence.SqlSyntax
             return items.Select(x => new Tuple<string, string, string, string>(x.TableName, x.ColumnName, x.Name, x.Definition));
         }
 
+        public override bool IsReadUncommittedSupported => true;
+        public override System.Data.IsolationLevel DefaultIsolationLevel => System.Data.IsolationLevel.ReadCommitted;
+
         public override IEnumerable<string> GetTablesInSchema(IDatabase db)
         {
             var items = db.Fetch<dynamic>("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = (SELECT SCHEMA_NAME())");
@@ -237,6 +241,44 @@ where tbl.[name]=@0 and col.[name]=@1;", tableName, columnName)
             return !constraintName.IsNullOrWhiteSpace();
         }
 
+        public override void WriteLock(IDatabase db, int? writeLockReasonId, params int[] lockIds)
+        {
+            // soon as we get Database, a transaction is started
+
+            if (db.Transaction.IsolationLevel < IsolationLevel.ReadCommitted)
+                throw new InvalidOperationException("A transaction with minimum ReadCommitted isolation level is required.");
+
+
+            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
+            foreach (var lockId in lockIds)
+            {
+                db.Execute(@"SET LOCK_TIMEOUT 1800;");
+                var i = db.Execute(@"UPDATE umbracoLock WITH (REPEATABLEREAD) SET value = value*-1, writeLockReasonId = @writeLockReasonId WHERE id=@id", new { id = lockId, writeLockReasonId = writeLockReasonId });
+                if (i == 0) // ensure we are actually locking!
+                    throw new Exception($"LockObject with id={lockId} does not exist.");
+            }
+        }
+
+        public override bool IsLockTimeoutException(Exception exception)
+        {
+            return exception is SqlException sqlException && sqlException.Number == 1222;
+        }
+
+        public override void ReadLock(IDatabase db, params int[] lockIds)
+        {
+            // soon as we get Database, a transaction is started
+
+            if (db.Transaction.IsolationLevel < IsolationLevel.ReadCommitted)
+                throw new InvalidOperationException("A transaction with minimum ReadCommitted isolation level is required.");
+
+            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
+            foreach (var lockId in lockIds)
+            {
+                var i = db.ExecuteScalar<int?>("SELECT value FROM umbracoLock WITH (REPEATABLEREAD) WHERE id=@id", new { id = lockId });
+                if (i == null) // ensure we are actually locking!
+                    throw new ArgumentException($"LockObject with id={lockId} does not exist.", nameof(lockIds));
+            }
+        }
         public override bool DoesTableExist(IDatabase db, string tableName)
         {
             var result =

src/Umbraco.Core/Persistence/SqlSyntax/SqlSyntaxProviderBase.cs

@@ -200,7 +200,10 @@ namespace Umbraco.Core.Persistence.SqlSyntax
 
             return "NVARCHAR";
         }
-        
+
+        public abstract bool IsReadUncommittedSupported { get; }
+        public abstract IsolationLevel DefaultIsolationLevel { get; }
+
         public virtual IEnumerable<string> GetTablesInSchema(IDatabase db)
         {
             return new List<string>();
@@ -224,6 +227,10 @@ namespace Umbraco.Core.Persistence.SqlSyntax
         public abstract IEnumerable<Tuple<string, string, string, bool>> GetDefinedIndexes(IDatabase db);
 
         public abstract bool TryGetDefaultConstraint(IDatabase db, string tableName, string columnName, out string constraintName);
+        public abstract void ReadLock(IDatabase db, params int[] lockIds);
+        public abstract void WriteLock(IDatabase db, int? writeLockReasonId, params int[] lockIds);
+        public abstract bool IsLockTimeoutException(Exception exception);
+
 
         public virtual bool DoesTableExist(IDatabase db, string tableName)
         {
@@ -559,5 +566,7 @@ namespace Umbraco.Core.Persistence.SqlSyntax
         public virtual string ConvertIntegerToOrderableString => "REPLACE(STR({0}, 8), SPACE(1), '0')";
         public virtual string ConvertDateToOrderableString => "CONVERT(nvarchar, {0}, 102)";
         public virtual string ConvertDecimalToOrderableString => "REPLACE(STR({0}, 20, 9), SPACE(1), '0')";
+
+
     }
 }

src/Umbraco.Core/Persistence/UmbracoDatabase.cs

@@ -20,9 +20,6 @@ namespace Umbraco.Core.Persistence
     /// </remarks>
     public class UmbracoDatabase : Database, IUmbracoDatabase
     {
-        // Umbraco's default isolation level is RepeatableRead
-        private const IsolationLevel DefaultIsolationLevel = IsolationLevel.RepeatableRead;
-
         private readonly ILogger _logger;
         private readonly RetryPolicy _connectionRetryPolicy;
         private readonly RetryPolicy _commandRetryPolicy;
@@ -38,7 +35,7 @@ namespace Umbraco.Core.Persistence
         /// <para>Also used by DatabaseBuilder for creating databases and installing/upgrading.</para>
         /// </remarks>
         public UmbracoDatabase(string connectionString, ISqlContext sqlContext, DbProviderFactory provider, ILogger logger, RetryPolicy connectionRetryPolicy = null, RetryPolicy commandRetryPolicy = null)
-            : base(connectionString, sqlContext.DatabaseType, provider, DefaultIsolationLevel)
+            : base(connectionString, sqlContext.DatabaseType, provider, sqlContext.SqlSyntax.DefaultIsolationLevel)
         {
             SqlContext = sqlContext;
 
@@ -54,7 +51,7 @@ namespace Umbraco.Core.Persistence
         /// </summary>
         /// <remarks>Internal for unit tests only.</remarks>
         internal UmbracoDatabase(DbConnection connection, ISqlContext sqlContext, ILogger logger)
-            : base(connection, sqlContext.DatabaseType, DefaultIsolationLevel)
+            : base(connection, sqlContext.DatabaseType, sqlContext.SqlSyntax.DefaultIsolationLevel)
         {
             SqlContext = sqlContext;
             _logger = logger;

src/Umbraco.Core/Persistence/UmbracoDatabaseFactory.cs

@@ -7,6 +7,7 @@ using NPoco.FluentMappings;
 using Umbraco.Core.Exceptions;
 using Umbraco.Core.Logging;
 using Umbraco.Core.Persistence.FaultHandling;
+using Umbraco.Core.Persistence.Interceptors;
 using Umbraco.Core.Persistence.Mappers;
 using Umbraco.Core.Persistence.SqlSyntax;
 
@@ -238,13 +239,15 @@ namespace Umbraco.Core.Persistence
             // so that everything NPoco is properly cached for the lifetime of the application
             _pocoMappers = new NPoco.MapperCollection { new PocoMapper() };
             var factory = new FluentPocoDataFactory(GetPocoDataFactoryResolver);
+
             _pocoDataFactory = factory;
             var config = new FluentConfig(xmappers => factory);
 
             // create the database factory
             _npocoDatabaseFactory = DatabaseFactory.Config(x => x
                 .UsingDatabase(CreateDatabaseInstance) // creating UmbracoDatabase instances
-                .WithFluentConfig(config)); // with proper configuration
+                .WithFluentConfig(config) // with proper configuration
+                .WithInterceptor(new LockTimeoutInterceptor()));
 
             if (_npocoDatabaseFactory == null)
                 throw new NullReferenceException("The call to UmbracoDatabaseFactory.Config yielded a null UmbracoDatabaseFactory instance.");

src/Umbraco.Core/Scoping/IScope.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
 using Umbraco.Core.Cache;
 using Umbraco.Core.Events;
 using Umbraco.Core.Persistence;
@@ -57,6 +59,29 @@ namespace Umbraco.Core.Scoping
         /// Write-locks some lock objects.
         /// </summary>
         /// <param name="lockIds">The lock object identifiers.</param>
+        [Obsolete("Use the overload with reason")]
+        [Browsable(false)]
         void WriteLock(params int[] lockIds);
+
+        /// <summary>
+        /// Write-locks some lock objects.
+        /// </summary>
+        /// <param name="writeLockReasonId">The id of the reason to take the write lock. See Constants.Locks.Reason.*</param>
+        /// <param name="lockIds">The lock object identifiers.</param>
+        void WriteLock(short writeLockReasonId, params int[] lockIds);
+
+        /// <summary>
+        /// Bypasses all db-locks and reads the WriteLockReasonId column on the specified locks.
+        /// </summary>
+        /// <param name="lockIds">The lock ids from the Constants.Locks.*</param>
+        /// <returns>A dictionary with the lock is as key, and the last started work as value. Note value can be null if we don't know or use SqlCe.</returns>
+        IDictionary<int, short> TrySpyLock(params int[] lockIds);
+
+        /// <summary>
+        /// Bypasses all db-locks and reads the WriteLockReasonId column on the specified lock.
+        /// </summary>
+        /// <param name="lockId">The lock id from the Constants.Locks.*</param>
+        /// <returns>The last started work. Note this can be null if we don't know or use SqlCe.</returns>
+        short TrySpyLock(int lockId);
     }
 }

src/Umbraco.Core/Scoping/Scope.cs

@@ -1,11 +1,15 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
 using System.Data;
+using System.Linq;
 using Umbraco.Core.Cache;
 using Umbraco.Core.Composing;
 using Umbraco.Core.Events;
 using Umbraco.Core.IO;
 using Umbraco.Core.Logging;
 using Umbraco.Core.Persistence;
+using Umbraco.Core.Persistence.Dtos;
 
 namespace Umbraco.Core.Scoping
 {
@@ -33,8 +37,6 @@ namespace Umbraco.Core.Scoping
         private ICompletable _fscope;
         private IEventDispatcher _eventDispatcher;
 
-        private const IsolationLevel DefaultIsolationLevel = IsolationLevel.RepeatableRead;
-
         // initializes a new scope
         private Scope(ScopeProvider scopeProvider,
             ILogger logger, FileSystems fileSystems, Scope parent, ScopeContext scopeContext, bool detachable,
@@ -205,7 +207,7 @@ namespace Umbraco.Core.Scoping
             {
                 if (_isolationLevel != IsolationLevel.Unspecified) return _isolationLevel;
                 if (ParentScope != null) return ParentScope.IsolationLevel;
-                return DefaultIsolationLevel;
+                return Database.SqlContext.SqlSyntax.DefaultIsolationLevel;
             }
         }
 
@@ -235,6 +237,7 @@ namespace Umbraco.Core.Scoping
                 try
                 {
                     _database.BeginTransaction(IsolationLevel);
+                    _database.Execute("SET LOCK_TIMEOUT 1800;");
                     return _database;
                 }
                 catch
@@ -490,35 +493,43 @@ namespace Umbraco.Core.Scoping
         /// <inheritdoc />
         public void ReadLock(params int[] lockIds)
         {
-            // soon as we get Database, a transaction is started
+            Database.SqlContext.SqlSyntax.ReadLock(Database, lockIds);
+        }
 
-            if (Database.Transaction.IsolationLevel < IsolationLevel.RepeatableRead)
-                throw new InvalidOperationException("A transaction with minimum RepeatableRead isolation level is required.");
+        /// <inheritdoc />
+        [Obsolete("Use the overload with reason")]
+        [Browsable(false)]
+        public void WriteLock(params int[] lockIds)
+        {
+            WriteLock(Constants.Locks.Reason.Default, lockIds);
+        }
 
-            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
-            foreach (var lockId in lockIds)
+        /// <inheritdoc />
+        public void WriteLock(short writeLockReasonId, params int[] lockIds)
+        {
+            Database.SqlContext.SqlSyntax.WriteLock(Database, writeLockReasonId, lockIds);
+        }
+
+        /// <inheritdoc />
+        public IDictionary<int, short> TrySpyLock(params int[] lockIds)
+        {
+            using (var db = _scopeProvider.DatabaseFactory.CreateDatabase())
             {
-                var i = Database.ExecuteScalar<int?>("SELECT value FROM umbracoLock WHERE id=@id", new { id = lockId });
-                if (i == null) // ensure we are actually locking!
-                    throw new Exception($"LockObject with id={lockId} does not exist.");
+                if (!db.SqlContext.SqlSyntax.IsReadUncommittedSupported)
+                {
+                    return lockIds.ToDictionary(x => x, x=> Constants.Locks.Reason.Default);
+                };
+
+                return db.Fetch<LockDto>("SELECT * FROM umbracoLock WITH (NOLOCK) WHERE id IN (@lockIds)", new { lockIds })
+                    .ToDictionary(x => x.Id, x => x.WriteLockReasonId);
+
             }
         }
 
         /// <inheritdoc />
-        public void WriteLock(params int[] lockIds)
+        public short TrySpyLock(int lockId)
         {
-            // soon as we get Database, a transaction is started
-
-            if (Database.Transaction.IsolationLevel < IsolationLevel.RepeatableRead)
-                throw new InvalidOperationException("A transaction with minimum RepeatableRead isolation level is required.");
-
-            // *not* using a unique 'WHERE IN' query here because the *order* of lockIds is important to avoid deadlocks
-            foreach (var lockId in lockIds)
-            {
-                var i = Database.Execute("UPDATE umbracoLock SET value = (CASE WHEN (value=1) THEN -1 ELSE 1 END) WHERE id=@id", new { id = lockId });
-                if (i == 0) // ensure we are actually locking!
-                    throw new Exception($"LockObject with id={lockId} does not exist.");
-            }
+            return TrySpyLock(new []{lockId})[lockId];
         }
     }
 }

src/Umbraco.Core/Services/Implement/ContentService.cs

@@ -32,7 +32,7 @@ namespace Umbraco.Core.Services.Implement
         private IQuery<IContent> _queryNotTrashed;
         //TODO: The non-lazy object should be injected
         private readonly Lazy<PropertyValidationService> _propertyValidationService = new Lazy<PropertyValidationService>(() => new PropertyValidationService());
-        
+
 
         #region Constructors
 
@@ -1666,7 +1666,7 @@ namespace Umbraco.Core.Services.Implement
                     return OperationResult.Cancel(evtMsgs);
                 }
 
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.EmptyRecycleBin, Constants.Locks.ContentTree);
 
                 // if it's not trashed yet, and published, we should unpublish
                 // but... Unpublishing event makes no sense (not going to cancel?) and no need to save
@@ -1790,7 +1790,7 @@ namespace Umbraco.Core.Services.Implement
 
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.MoveContentToRecycleBin, Constants.Locks.ContentTree);
 
                 var originalPath = content.Path;
                 var moveEventInfo = new MoveEventInfo<IContent>(content, originalPath, Constants.System.RecycleBinContent);
@@ -1849,7 +1849,7 @@ namespace Umbraco.Core.Services.Implement
 
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.MoveContent, Constants.Locks.ContentTree);
 
                 var parent = parentId == Constants.System.Root ? null : GetById(parentId);
                 if (parentId != Constants.System.Root && (parent == null || parent.Trashed))
@@ -1969,7 +1969,7 @@ namespace Umbraco.Core.Services.Implement
 
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.EmptyRecycleBin, Constants.Locks.ContentTree);
 
                 // v7 EmptyingRecycleBin and EmptiedRecycleBin events are greatly simplified since
                 // each deleted items will have its own deleting/deleted events. so, files and such
@@ -2052,7 +2052,7 @@ namespace Umbraco.Core.Services.Implement
 
                 var copies = new List<Tuple<IContent, IContent>>();
 
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.CopyContent, Constants.Locks.ContentTree);
 
                 // a copy is not published (but not really unpublishing either)
                 // update the create author and last edit author
@@ -2198,7 +2198,7 @@ namespace Umbraco.Core.Services.Implement
 
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.SortContent, Constants.Locks.ContentTree);
 
                 var ret = Sort(scope, itemsA, userId, evtMsgs, raiseEvents);
                 scope.Complete();
@@ -2227,7 +2227,7 @@ namespace Umbraco.Core.Services.Implement
 
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.SortContent, Constants.Locks.ContentTree);
                 var itemsA = GetByIds(idsA).ToArray();
 
                 var ret = Sort(scope, itemsA, userId, evtMsgs, raiseEvents);
@@ -2729,7 +2729,7 @@ namespace Umbraco.Core.Services.Implement
             //
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.WriteLock(Constants.Locks.ContentTree);
+                scope.WriteLock(Constants.Locks.Reason.DeleteContentOfTypes,Constants.Locks.ContentTree);
 
                 var query = Query<IContent>().WhereIn(x => x.ContentTypeId, contentTypeIdsA);
                 var contents = _documentRepository.Get(query).ToArray();
@@ -3028,6 +3028,6 @@ namespace Umbraco.Core.Services.Implement
         #endregion
 
 
-        
+
     }
 }

src/Umbraco.Core/Services/Implement/EntityService.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using Umbraco.Core.Events;
+using Umbraco.Core.Exceptions;
 using Umbraco.Core.Logging;
 using Umbraco.Core.Models;
 using Umbraco.Core.Models.Entities;
@@ -257,20 +258,38 @@ namespace Umbraco.Core.Services.Implement
         /// <inheritdoc />
         public virtual IEnumerable<IEntitySlim> GetChildren(int parentId)
         {
-            using (ScopeProvider.CreateScope(autoComplete: true))
+            using (var scope = ScopeProvider.CreateScope(autoComplete: true))
             {
-                var query = Query<IUmbracoEntity>().Where(x => x.ParentId == parentId);
-                return _entityRepository.GetByQuery(query);
+                try
+                {
+                    var query = Query<IUmbracoEntity>().Where(x => x.ParentId == parentId);
+                    return _entityRepository.GetByQuery(query);
+                }
+                catch (LockTimeoutException e)
+                {
+                    e.Reason = scope.TrySpyLock(Constants.Locks.ContentTree);
+
+                    throw;
+                }
             }
         }
 
         /// <inheritdoc />
         public virtual IEnumerable<IEntitySlim> GetChildren(int parentId, UmbracoObjectTypes objectType)
         {
-            using (ScopeProvider.CreateScope(autoComplete: true))
+            using (var scope = ScopeProvider.CreateScope(autoComplete: true))
             {
-                var query = Query<IUmbracoEntity>().Where(x => x.ParentId == parentId);
-                return _entityRepository.GetByQuery(query, objectType.GetGuid());
+                try
+                {
+                    var query = Query<IUmbracoEntity>().Where(x => x.ParentId == parentId);
+                    return _entityRepository.GetByQuery(query, objectType.GetGuid());
+                }
+                catch (LockTimeoutException e)
+                {
+                    e.Reason = scope.TrySpyLock(Constants.Locks.ContentTree);
+
+                    throw;
+                }
             }
         }
 

src/Umbraco.Core/Services/LocalizedTextServiceExtensions.cs

@@ -18,6 +18,11 @@ namespace Umbraco.Core.Services
             return manager.Localize(fullKey, Thread.CurrentThread.CurrentUICulture);
         }
 
+        public static string LocalizeLockReason(this ILocalizedTextService manager, short writeLockReasonId)
+        {
+            return manager.Localize($"writeLockReasons/Code_{writeLockReasonId}", Thread.CurrentThread.CurrentUICulture);
+        }
+
         /// <summary>
         /// Localize using the current thread culture
         /// </summary>

src/Umbraco.Core/Umbraco.Core.csproj

@@ -204,6 +204,7 @@
     <Compile Include="CompositionExtensions_Essentials.cs" />
     <Compile Include="CompositionExtensions_FileSystems.cs" />
     <Compile Include="CompositionExtensions_Uniques.cs" />
+    <Compile Include="Exceptions\LockTimeoutException.cs" />
     <Compile Include="FactoryExtensions.cs" />
     <Compile Include="Composing\RegisterFactory.cs" />
     <Compile Include="Composing\Current.cs" />
@@ -243,6 +244,7 @@
     <Compile Include="Migrations\Upgrade\V_8_0_0\DataTypes\RichTextPreValueMigrator.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\DataTypes\DropDownFlexiblePreValueMigrator.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\MergeDateAndDateTimePropertyEditor.cs" />
+    <Compile Include="Migrations\Upgrade\V_8_2_0\AddLockTableColumns.cs" />
     <Compile Include="Models\Entities\EntityExtensions.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\DataTypes\PreValueMigratorBase.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\DataTypes\PreValueDto.cs" />
@@ -265,6 +267,7 @@
     <Compile Include="Models\PublishedContent\ILivePublishedModelFactory.cs" />
     <Compile Include="Models\PublishedContent\IPublishedContentType.cs" />
     <Compile Include="Models\PublishedContent\IPublishedPropertyType.cs" />
+    <Compile Include="Persistence\Interceptors\LockTimeoutInterceptor.cs" />
     <Compile Include="PropertyEditors\IIgnoreUserStartNodesConfig.cs" />
     <Compile Include="PublishedContentExtensions.cs" />
     <Compile Include="Models\PublishedContent\UrlMode.cs" />
@@ -979,7 +982,6 @@
     <Compile Include="Persistence\DatabaseModelDefinitions\ModificationType.cs" />
     <Compile Include="Persistence\DatabaseModelDefinitions\SystemMethods.cs" />
     <Compile Include="Persistence\DatabaseModelDefinitions\TableDefinition.cs" />
-    <Compile Include="Persistence\DatabaseNodeLockExtensions.cs" />
     <Compile Include="Persistence\DbCommandExtensions.cs" />
     <Compile Include="Persistence\DbConnectionExtensions.cs" />
     <Compile Include="Persistence\EntityNotFoundException.cs" />

src/Umbraco.Tests/Models/UserExtensionsTests.cs

@@ -56,6 +56,8 @@ namespace Umbraco.Tests.Models
 
         [TestCase("1,-1", "1", "1")] // was an issue
         [TestCase("-1,1", "1", "1")] // was an issue
+        [TestCase("-1", "", "-1")]
+        [TestCase("", "-1", "-1")]
 
         public void CombineStartNodes(string groupSn, string userSn, string expected)
         {

src/Umbraco.Tests/Persistence/LocksTests.cs

@@ -5,6 +5,7 @@ using System.Threading;
 using NPoco;
 using NUnit.Framework;
 using Umbraco.Core;
+using Umbraco.Core.Exceptions;
 using Umbraco.Core.Persistence;
 using Umbraco.Core.Persistence.Dtos;
 using Umbraco.Tests.TestHelpers;
@@ -37,7 +38,7 @@ namespace Umbraco.Tests.Persistence
         {
             using (var scope = ScopeProvider.CreateScope())
             {
-                scope.Database.AcquireLockNodeReadLock(Constants.Locks.Servers);
+                scope.WriteLock(Constants.Locks.Reason.Default, Constants.Locks.Servers);
                 scope.Complete();
             }
         }
@@ -62,7 +63,7 @@ namespace Umbraco.Tests.Persistence
                     {
                         try
                         {
-                            scope.Database.AcquireLockNodeReadLock(Constants.Locks.Servers);
+                            scope.ReadLock(Constants.Locks.Servers);
                             lock (locker)
                             {
                                 acquired++;
@@ -131,7 +132,7 @@ namespace Umbraco.Tests.Persistence
                                 if (entered == threadCount) m1.Set();
                             }
                             ms[ic].WaitOne();
-                            scope.Database.AcquireLockNodeWriteLock(Constants.Locks.Servers);
+                            scope.WriteLock(Constants.Locks.Reason.Default,Constants.Locks.Servers);
                             lock (locker)
                             {
                                 acquired++;
@@ -201,7 +202,7 @@ namespace Umbraco.Tests.Persistence
             thread2.Join();
 
             Assert.IsNotNull(e1);
-            Assert.IsInstanceOf<SqlCeLockTimeoutException>(e1);
+            Assert.IsInstanceOf<LockTimeoutException>(e1);
 
             // the assertion below depends on timing conditions - on a fast enough environment,
             // thread1 dies (deadlock) and frees thread2, which succeeds - however on a slow
@@ -210,7 +211,7 @@ namespace Umbraco.Tests.Persistence
             //
             //Assert.IsNull(e2);
             if (e2 != null)
-                Assert.IsInstanceOf<SqlCeLockTimeoutException>(e2);
+                Assert.IsInstanceOf<LockTimeoutException>(e2);
         }
 
         private void DeadLockTestThread(int id1, int id2, EventWaitHandle myEv, WaitHandle otherEv, ref Exception exception)
@@ -221,7 +222,7 @@ namespace Umbraco.Tests.Persistence
                 {
                     otherEv.WaitOne();
                     Console.WriteLine($"[{id1}] WAIT {id1}");
-                    scope.Database.AcquireLockNodeWriteLock(id1);
+                    scope.WriteLock(Constants.Locks.Reason.Default,id1);
                     Console.WriteLine($"[{id1}] GRANT {id1}");
                     WriteLocks(scope.Database);
                     myEv.Set();
@@ -232,7 +233,7 @@ namespace Umbraco.Tests.Persistence
                         Thread.Sleep(200); // cannot wait due to deadlock... just give it a bit of time
 
                     Console.WriteLine($"[{id1}] WAIT {id2}");
-                    scope.Database.AcquireLockNodeWriteLock(id2);
+                    scope.WriteLock(Constants.Locks.Reason.Default,id2);
                     Console.WriteLine($"[{id1}] GRANT {id2}");
                     WriteLocks(scope.Database);
                 }
@@ -284,7 +285,7 @@ namespace Umbraco.Tests.Persistence
                 {
                     otherEv.WaitOne();
                     Console.WriteLine($"[{id}] WAIT {id}");
-                    scope.Database.AcquireLockNodeWriteLock(id);
+                    scope.WriteLock(Constants.Locks.Reason.Default, id);
                     Console.WriteLine($"[{id}] GRANT {id}");
                     WriteLocks(scope.Database);
                     myEv.Set();

src/Umbraco.Web.UI.Client/package-lock.json

@@ -1222,7 +1222,7 @@
     "arraybuffer.slice": {
       "version": "0.0.7",
       "resolved": "https://registry.npmjs.org/arraybuffer.slice/-/arraybuffer.slice-0.0.7.tgz",
-      "integrity": "sha512-wGUIVQXuehL5TCqQun8OW81jGzAWycqzFF8lFp+GOM5BXLYj3bKNsYC4daB7n6XjCqxQA/qgTJ+8ANR3acjrog==",
+      "integrity": "sha1-O7xCdd1YTMGxCAm4nU6LY6aednU=",
       "dev": true
     },
     "asap": {
@@ -1284,7 +1284,7 @@
     "async-limiter": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/async-limiter/-/async-limiter-1.0.0.tgz",
-      "integrity": "sha512-jp/uFnooOiO+L211eZOoSyzpOITMXx1rBITauYykG3BRYPu8h0UcxsPNB04RR5vo4Tyz3+ay17tR6JVf9qzYWg==",
+      "integrity": "sha1-ePrtjD0HSrgfIrTphdeehzj3IPg=",
       "dev": true
     },
     "asynckit": {
@@ -1535,7 +1535,7 @@
     },
     "bl": {
       "version": "1.2.2",
-      "resolved": "https://registry.npmjs.org/bl/-/bl-1.2.2.tgz",
+      "resolved": "http://registry.npmjs.org/bl/-/bl-1.2.2.tgz",
       "integrity": "sha512-e8tQYnZodmebYDWGH7KMRvtzKXaJHx3BbilrgZCfvyLUYdKpK1t5PSPmpkny/SgiTSCnjfLW7v5rlONXVFkQEA==",
       "dev": true,
       "requires": {
@@ -2516,7 +2516,7 @@
     "content-type": {
       "version": "1.0.4",
       "resolved": "https://registry.npmjs.org/content-type/-/content-type-1.0.4.tgz",
-      "integrity": "sha512-hIP3EEPs8tB9AT1L+NUqtwOAps4mk2Zob89MWXMHjHWg9milF/j4osnnQLXBCBFBk/tvIG/tUc9mOUJiPBhPXA==",
+      "integrity": "sha1-4TjMdeBAxyexlm/l5fjJruJW/js=",
       "dev": true
     },
     "continuable-cache": {
@@ -4045,7 +4045,7 @@
         "debug": {
           "version": "3.1.0",
           "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
-          "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+          "integrity": "sha1-W7WgZyYotkFJVmuhaBnmFRjGcmE=",
           "dev": true,
           "requires": {
             "ms": "2.0.0"
@@ -4081,7 +4081,7 @@
         "debug": {
           "version": "3.1.0",
           "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
-          "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+          "integrity": "sha1-W7WgZyYotkFJVmuhaBnmFRjGcmE=",
           "dev": true,
           "requires": {
             "ms": "2.0.0"
@@ -4476,7 +4476,7 @@
     "eventemitter3": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-3.1.0.tgz",
-      "integrity": "sha512-ivIvhpq/Y0uSjcHDcOIccjmYjGLcP09MFGE7ysAwkAvkXfpZlC985pH2/ui64DKazbTW/4kN3yqozUxlXzI6cA==",
+      "integrity": "sha1-CQtNbNvWRe0Qv3UNS1QHlC17oWM=",
       "dev": true
     },
     "exec-buffer": {
@@ -5309,8 +5309,7 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -5331,14 +5330,12 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -5353,20 +5350,17 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -5483,8 +5477,7 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "ini": {
           "version": "1.3.5",
@@ -5496,7 +5489,6 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -5511,7 +5503,6 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -5519,14 +5510,12 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "minipass": {
           "version": "2.2.4",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.1",
             "yallist": "^3.0.0"
@@ -5545,7 +5534,6 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -5626,8 +5614,7 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -5639,7 +5626,6 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -5725,8 +5711,7 @@
         "safe-buffer": {
           "version": "5.1.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -5762,7 +5747,6 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -5782,7 +5766,6 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -5826,14 +5809,12 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "yallist": {
           "version": "3.0.2",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         }
       }
     },
@@ -7575,7 +7556,7 @@
     "has-binary2": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/has-binary2/-/has-binary2-1.0.3.tgz",
-      "integrity": "sha512-G1LWKhDSvhGeAQ8mPVQlqNcOB2sJdwATtZKl2pDKKHfpf/rYj24lkinxf69blJbnsvtqqNU+L3SL50vzZhXOnw==",
+      "integrity": "sha1-d3asYn8+p3JQz8My2rfd9eT10R0=",
       "dev": true,
       "requires": {
         "isarray": "2.0.1"
@@ -7778,7 +7759,7 @@
     "http-proxy": {
       "version": "1.17.0",
       "resolved": "https://registry.npmjs.org/http-proxy/-/http-proxy-1.17.0.tgz",
-      "integrity": "sha512-Taqn+3nNvYRfJ3bGvKfBSRwy1v6eePlm3oc/aWVxZp57DQr5Eq3xhKJi7Z4hZpS8PC3H4qI+Yly5EmFacGuA/g==",
+      "integrity": "sha1-etOElGWPhGBeL220Q230EPTlvpo=",
       "dev": true,
       "requires": {
         "eventemitter3": "^3.0.0",
@@ -13616,7 +13597,7 @@
     "qjobs": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/qjobs/-/qjobs-1.2.0.tgz",
-      "integrity": "sha512-8YOJEHtxpySA3fFDyCRxA+UUV+fA+rTWnuWvylOK/NCjhY+b4ocCtmu8TtsWb+mYeU+GCHf/S66KZF/AsteKHg==",
+      "integrity": "sha1-xF6cYYAL0IfviNfiVkI73Unl0HE=",
       "dev": true
     },
     "qs": {
@@ -14787,7 +14768,7 @@
         "debug": {
           "version": "3.1.0",
           "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
-          "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+          "integrity": "sha1-W7WgZyYotkFJVmuhaBnmFRjGcmE=",
           "dev": true,
           "requires": {
             "ms": "2.0.0"
@@ -15860,7 +15841,7 @@
     "type-is": {
       "version": "1.6.16",
       "resolved": "https://registry.npmjs.org/type-is/-/type-is-1.6.16.tgz",
-      "integrity": "sha512-HRkVv/5qY2G6I8iab9cI7v1bOIdhm94dVjQCPFElW9W+3GeDOSHmy2EBYe4VTApuzolPcmgFTN3ftVJRKR2J9Q==",
+      "integrity": "sha1-+JzjQVQcZysl7nrjxz3uOyvlAZQ=",
       "dev": true,
       "requires": {
         "media-typer": "0.3.0",
@@ -15902,7 +15883,7 @@
     "ultron": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/ultron/-/ultron-1.1.1.tgz",
-      "integrity": "sha512-UIEXBNeYmKptWH6z8ZnqTeS8fV74zG0/eRU9VGkpzz+LIJNs8W/zM/L+7ctCkRrgbNnnR0xxw4bKOr0cW0N0Og==",
+      "integrity": "sha1-n+FTahCmZKZSZqHjzPhf02MCvJw=",
       "dev": true
     },
     "unc-path-regex": {
@@ -16505,7 +16486,7 @@
     "ws": {
       "version": "3.3.3",
       "resolved": "https://registry.npmjs.org/ws/-/ws-3.3.3.tgz",
-      "integrity": "sha512-nnWLa/NwZSt4KQJu51MYlCcSQ5g7INpOrOMt4XV8j4dqTXdmlUmSHQ8/oLC069ckre0fRsgfvsKwbTdtKLCDkA==",
+      "integrity": "sha1-8c+E/i1ekB686U767OeF8YeiKPI=",
       "dev": true,
       "requires": {
         "async-limiter": "~1.0.0",

src/Umbraco.Web.UI.Client/src/common/directives/components/tree/umbtree.directive.js

@@ -3,7 +3,7 @@
 * @name umbraco.directives.directive:umbTree
 * @restrict E
 **/
-function umbTreeDirective($q, $rootScope, treeService, notificationsService, userService) {
+function umbTreeDirective($q, $rootScope, treeService, notificationsService, userService,  $timeout) {
 
     return {
         restrict: 'E',
@@ -234,6 +234,8 @@ function umbTreeDirective($q, $rootScope, treeService, notificationsService, use
 
             /** Method to load in the tree data */
             function loadTree() {
+               
+                
                 if ($scope.section) {
 
                     //default args
@@ -243,33 +245,52 @@ function umbTreeDirective($q, $rootScope, treeService, notificationsService, use
                     if ($scope.customtreeparams) {
                         args["queryString"] = $scope.customtreeparams;
                     }
-
-                    return treeService.getTree(args)
-                        .then(function (data) {
-                            //Only use the tree data, if we are still on the correct section
-                            if(data.alias !== $scope.section){
-                                return $q.reject();
-                            }
-                            
-                            //set the data once we have it
-                            $scope.tree = data;
-
-                            //set the root as the current active tree
-                            $scope.activeTree = $scope.tree.root;
-
-                            emitEvent("treeLoaded", { tree: $scope.tree });
-                            emitEvent("treeNodeExpanded", { tree: $scope.tree, node: $scope.tree.root, children: $scope.tree.root.children });
-                         
-                            return $q.when(data);
-                        }, function (reason) {
-                            notificationsService.error("Tree Error", reason);
-                            return $q.reject(reason);
-                        });
+                    
+                    $scope.isLoading = true;
+                    $scope.isLoadingReason = "";
+                    
+                    return getTree(args);
                 }
                 else {
                     return $q.reject();
                 }
             }
+            
+            function getTree(args){
+                return treeService.getTree(args)
+                    .then(function (data) {
+
+
+                        //Only use the tree data, if we are still on the correct section
+                        if(data.alias !== $scope.section){
+                            return $q.reject();
+                        }
+
+                        //set the data once we have it
+                        $scope.tree = data;
+
+                        //set the root as the current active tree
+                        $scope.activeTree = $scope.tree.root;
+
+                        emitEvent("treeLoaded", { tree: $scope.tree });
+                        emitEvent("treeNodeExpanded", { tree: $scope.tree, node: $scope.tree.root, children: $scope.tree.root.children });
+
+                        $scope.isLoading = false;
+                        $scope.isLoadingReason = "";
+                        return $q.when(data);
+                    }, function (reason) {
+                        if(reason.status === 409){
+                            $scope.isLoading = true;
+                            $scope.isLoadingReason = reason.data;
+
+                            $timeout(function() { $q.when(getTree(args));}, 5000);
+                        }else{
+                            notificationsService.error("Tree Error", reason);
+                            return $q.reject(reason);
+                        }
+
+                    });
+            }
 
             function loadChildren(node, forceReload) {
                 //emit treeNodeExpanding event, if a callback object is set on the tree

src/Umbraco.Web.UI.Client/src/views/components/tree/umb-tree.html

@@ -1,53 +1,62 @@
-<ul class="umb-tree" ng-class="{'hide-options': hideoptions === 'true'}">
+<div>
+    <div ng-if="isLoading">
+        <umb-load-indicator></umb-load-indicator>
+        <div style="position: absolute; top: 50%; padding-top: 30px; text-align: center; width: 76%; padding-left: 13%;">{{isLoadingReason}}</div>
+    </div>
 
-    <li ng-if="!tree.root.containsGroups">
-        <div class="umb-tree-root" data-element="tree-root" ng-class="getNodeCssClass(tree.root)" ng-hide="hideheader === 'true'" on-right-click="altSelect(tree.root, $event)">
-            <h5>
-                <a ng-href="#/{{section}}" ng-click="select(tree.root, $event)" class="umb-tree-root-link umb-outline" data-element="tree-root-link">
-                    <i ng-if="enablecheckboxes === 'true'" ng-class="selectEnabledNodeClass(tree.root)"></i>
-                    {{tree.name}}
-                </a>
-            </h5>
-            <button data-element="tree-item-options" class="umb-options btn-reset sr-only sr-only--focusable sr-only--hoverable" ng-hide="tree.root.isContainer || !tree.root.menuUrl" ng-click="options(tree.root, $event)" ng-swipe-right="options(tree.root, $event)">
-                <i></i><i></i><i></i>
-            </button>
-        </div>
-        <umb-tree-item class="umb-animated"
-                       ng-repeat="child in tree.root.children"
-                       enablelistviewexpand="{{enablelistviewexpand}}"
-                       node="child"
-                       current-node="currentNode"
-                       tree="this"
-                       is-dialog="isdialog"
-                       section="{{section}}">
-        </umb-tree-item>
-    </li>
+    <div ng-if="!isLoading">
+        <ul class="umb-tree" ng-class="{'hide-options': hideoptions === 'true'}">
 
-    <!-- REPEAT for each group in the tree -->
-    <li ng-if="tree.root.containsGroups"
-        ng-repeat="group in tree.root.children">
+            <li ng-if="!tree.root.containsGroups">
+                <div class="umb-tree-root" data-element="tree-root" ng-class="getNodeCssClass(tree.root)" ng-hide="hideheader === 'true'" on-right-click="altSelect(tree.root, $event)">
+                    <h5>
+                        <a ng-href="#/{{section}}" ng-click="select(tree.root, $event)" class="umb-tree-root-link umb-outline" data-element="tree-root-link">
+                            <i ng-if="enablecheckboxes === 'true'" ng-class="selectEnabledNodeClass(tree.root)"></i>
+                            {{tree.name}}
+                        </a>
+                    </h5>
+                    <button data-element="tree-item-options" class="umb-options btn-reset sr-only sr-only--focusable sr-only--hoverable" ng-hide="tree.root.isContainer || !tree.root.menuUrl" ng-click="options(tree.root, $event)" ng-swipe-right="options(tree.root, $event)">
+                        <i></i><i></i><i></i>
+                    </button>
+                </div>
+                <umb-tree-item class="umb-animated"
+                               ng-repeat="child in tree.root.children"
+                               enablelistviewexpand="{{enablelistviewexpand}}"
+                               node="child"
+                               current-node="currentNode"
+                               tree="this"
+                               is-dialog="isdialog"
+                               section="{{section}}">
+                </umb-tree-item>
+            </li>
 
-        <div class="umb-tree-root" data-element="tree-root" ng-class="getNodeCssClass(group)" ng-hide="hideheader === 'true'" on-right-click="altSelect(group, $event)">
-            <h5>
-                <a ng-href="#/{{section}}" ng-click="select(group, $event)" class="umb-tree-root-link umb-outline" data-element="tree-root-link">
-                    <i ng-if="enablecheckboxes === 'true'" ng-class="selectEnabledNodeClass(group)"></i>
-                    {{group.name}}
-                </a>
-            </h5>
-            <button data-element="tree-item-options" class="umb-options umb-outline btn-reset sr-only sr-only--focusable sr-only--hoverable" ng-hide="group.isContainer || !group.menuUrl" ng-click="options(group, $event)" ng-swipe-right="options(group, $event)">
-                <i></i><i></i><i></i>
-            </button>
-        </div>
+            <!-- REPEAT for each group in the tree -->
+            <li ng-if="tree.root.containsGroups"
+                ng-repeat="group in tree.root.children">
 
-        <umb-tree-item class="umb-animated"
-                       ng-repeat="child in group.children"
-                       enablelistviewexpand="{{enablelistviewexpand}}"
-                       node="child"
-                       current-node="currentNode"
-                       tree="this"
-                       is-dialog="isdialog"
-                       section="{{section}}">
-        </umb-tree-item>
-    </li>
-    <!-- END REPEAT -->
-</ul>
+                <div class="umb-tree-root" data-element="tree-root" ng-class="getNodeCssClass(group)" ng-hide="hideheader === 'true'" on-right-click="altSelect(group, $event)">
+                    <h5>
+                        <a ng-href="#/{{section}}" ng-click="select(group, $event)" class="umb-tree-root-link umb-outline" data-element="tree-root-link">
+                            <i ng-if="enablecheckboxes === 'true'" ng-class="selectEnabledNodeClass(group)"></i>
+                            {{group.name}}
+                        </a>
+                    </h5>
+                    <button data-element="tree-item-options" class="umb-options umb-outline btn-reset sr-only sr-only--focusable sr-only--hoverable" ng-hide="group.isContainer || !group.menuUrl" ng-click="options(group, $event)" ng-swipe-right="options(group, $event)">
+                        <i></i><i></i><i></i>
+                    </button>
+                </div>
+
+                <umb-tree-item class="umb-animated"
+                               ng-repeat="child in group.children"
+                               enablelistviewexpand="{{enablelistviewexpand}}"
+                               node="child"
+                               current-node="currentNode"
+                               tree="this"
+                               is-dialog="isdialog"
+                               section="{{section}}">
+                </umb-tree-item>
+            </li>
+            <!-- END REPEAT -->
+        </ul>
+    </div>
+</div>

src/Umbraco.Web.UI/Umbraco/config/lang/da.xml

@@ -263,7 +263,7 @@
     <key alias="scheduledPublishDocumentation"><![CDATA[<a href="https://our.umbraco.com/documentation/Getting-Started/Data/Scheduled-Publishing/#timezones" target="_blank">Hvad betyder det?</a>]]></key>
     <key alias="nestedContentDeleteItem">Er du sikker på, at du vil slette dette element?</key>
     <key alias="nestedContentEditorNotSupported">Egenskaben %0% anvender editoren %1% som ikke er understøttet af Nested Content.</key>
-    <key alias="nestedContentNoContentTypes">Der er ikke konfigureret nogen indholdstyper for denne egenskab.</key>
+    <key alias="nestedContentNoContentTypes">Der er ikke konfigureret nogen indholdstyper for denne egenskab.</key>
     <key alias="addTextBox">Tilføj en ny tekstboks</key>
     <key alias="removeTextBox">Fjern denne tekstboks</key>
     <key alias="contentRoot">Indholdsrod</key>
@@ -284,8 +284,8 @@
     <key alias="readyToPublish">Klar til at udgive?</key>
     <key alias="readyToSave">Klar til at gemme?</key>
     <key alias="sendForApproval">Send til godkendelse</key>
-    <key alias="schedulePublishHelp">Vælg dato og klokkeslæt for at udgive og/eller afpublicere indholdet.</key>
-    <key alias="createEmpty">Opret ny</key>
+    <key alias="schedulePublishHelp">Vælg dato og klokkeslæt for at udgive og/eller afpublicere indholdet.</key>
+    <key alias="createEmpty">Opret ny</key>
     <key alias="createFromClipboard">Indsæt fra udklipsmappen</key>
   </area>
   <area alias="blueprints">
@@ -1571,8 +1571,8 @@ Mange hilsner fra Umbraco robotten
   <area alias="emptyStates">
     <key alias="emptyDictionaryTree">Ingen ordbog elementer at vælge imellem</key>
   </area>
-  <area alias="textbox">
-    <key alias="characters_left"><![CDATA[<strong>%0%</strong> tegn tilbage.]]></key>
+  <area alias="textbox">
+    <key alias="characters_left"><![CDATA[<strong>%0%</strong> tegn tilbage.]]></key>
     <key alias="characters_exceed"><![CDATA[Maksimum %0% tegn, <strong>%1%</strong> for mange.]]></key>
   </area>
   <area alias="recycleBin">
@@ -1606,8 +1606,18 @@ Mange hilsner fra Umbraco robotten
     <key alias="settingsPublishedStatus">Published Cache</key>
     <key alias="settingsModelsBuilder">Models Builder</key>
     <key alias="settingsHealthCheck">Health Check</key>
-    <key alias="settingsProfiler">Profiling</key>
+    <key alias="settingsProfiler">Profiling</key>
     <key alias="memberIntro">Kom godt i gang</key>
     <key alias="formsInstall">Installer Umbraco Forms</key>
   </area>
+    <area alias="writeLockReasons">
+        <key alias="Code_1">Langvaring operation</key>
+        <key alias="Code_10000">Flytter indhold til papirkurven</key>
+        <key alias="Code_10001">Genskaber indhold fra papirkurven</key>
+        <key alias="Code_10002">Sletter indhold fra papirkurven</key>
+        <key alias="Code_10003">Flytter indhold</key>
+        <key alias="Code_10004">Kopier indhold</key>
+        <key alias="Code_10005">Sorterer indhold</key>
+        <key alias="Code_10006">Sletter alt indhold af en type</key>
+    </area>
 </language>

src/Umbraco.Web.UI/Umbraco/config/lang/en.xml

@@ -334,7 +334,7 @@
     <key alias="noDocumentTypesEditPermissions">Edit permissions for this document type</key>
     <key alias="noMediaTypes" version="7.0"><![CDATA[There are no allowed media types available for creating media here. You must enable these in <strong>Media Types Types</strong> within the <strong>Settings</strong> section, by editing the <strong>Allowed child node types</strong> under <strong>Permissions</strong>.]]></key>
     <key alias="noMediaTypesWithNoSettingsAccess">The selected media in the tree doesn't allow for any other media to be created below it.</key>
-    <key alias="noMediaTypesEditPermissions">Edit permissions for this media type</key>
+    <key alias="noMediaTypesEditPermissions">Edit permissions for this media type</key>
     <key alias="documentTypeWithoutTemplate">Document Type without a template</key>
     <key alias="newFolder">New folder</key>
     <key alias="newDataType">New data type</key>
@@ -1130,7 +1130,7 @@ To manage your website, simply open the Umbraco back office and start adding con
     <key alias="cancelAndUploadAnother">Cancel and upload another package</key>
     <key alias="accept">I accept</key>
     <key alias="termsOfUse">terms of use</key>
-    
+
     <key alias="pathToFile">Path to file</key>
     <key alias="pathToFileDescription">Absolute path to file (ie: /bin/umbraco.bin)</key>
     <key alias="installed">Installed</key>
@@ -2121,8 +2121,18 @@ To manage your website, simply open the Umbraco back office and start adding con
     <key alias="settingsPublishedStatus">Published Status</key>
     <key alias="settingsModelsBuilder">Models Builder</key>
     <key alias="settingsHealthCheck">Health Check</key>
-    <key alias="settingsProfiler">Profiling</key>
+    <key alias="settingsProfiler">Profiling</key>
     <key alias="memberIntro">Getting Started</key>
     <key alias="formsInstall">Install Umbraco Forms</key>
-  </area>>
+  </area>
+    <area alias="writeLockReasons">
+        <key alias="Code_1">Langvaring operation</key>
+        <key alias="Code_10000">Move content to recycle bin</key>
+        <key alias="Code_10001">Restores content from recycle bin</key>
+        <key alias="Code_10002">Deletes content from recycle bin</key>
+        <key alias="Code_10003">Moves content</key>
+        <key alias="Code_10004">Copying content</key>
+        <key alias="Code_10005">Sort content</key>
+        <key alias="Code_10006">Deletes all content of a given type</key>
+    </area>
 </language>

src/Umbraco.Web.UI/Umbraco/config/lang/en_us.xml

@@ -2135,8 +2135,18 @@ To manage your website, simply open the Umbraco back office and start adding con
     <key alias="settingsPublishedStatus">Published Status</key>
     <key alias="settingsModelsBuilder">Models Builder</key>
     <key alias="settingsHealthCheck">Health Check</key>
-    <key alias="settingsProfiler">Profiling</key>
+    <key alias="settingsProfiler">Profiling</key>
     <key alias="memberIntro">Getting Started</key>
     <key alias="formsInstall">Install Umbraco Forms</key>
   </area>
+    <area alias="writeLockReasons">
+        <key alias="Code_1">Langvaring operation</key>
+        <key alias="Code_10000">Move content to recycle bin</key>
+        <key alias="Code_10001">Restores content from recycle bin</key>
+        <key alias="Code_10002">Deletes content from recycle bin</key>
+        <key alias="Code_10003">Moves content</key>
+        <key alias="Code_10004">Copying content</key>
+        <key alias="Code_10005">Sort content</key>
+        <key alias="Code_10006">Deletes all content of a given type</key>
+    </area>
 </language>

src/Umbraco.Web/Media/TypeDetector/SvgDetector.cs

@@ -13,7 +13,7 @@ namespace Umbraco.Web.Media.TypeDetector
             {
                 document = XDocument.Load(fileStream);
             }
-            catch (System.Exception ex)
+            catch (System.Exception)
             {
                 return false;
             }

src/Umbraco.Web/Umbraco.Web.csproj

@@ -321,6 +321,7 @@
     <Compile Include="WebApi\Filters\HttpQueryStringModelBinder.cs" />
     <Compile Include="WebApi\HttpActionContextExtensions.cs" />
     <Compile Include="Models\ContentEditing\IContentSave.cs" />
+    <Compile Include="WebApi\LockTimeoutExceptionHandlerAttribute.cs" />
     <Compile Include="WebApi\SerializeVersionAttribute.cs" />
     <Compile Include="WebApi\TrimModelBinder.cs" />
     <Compile Include="Editors\CodeFileController.cs" />

src/Umbraco.Web/WebApi/LockTimeoutExceptionHandlerAttribute.cs

@@ -0,0 +1,33 @@
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Web.Http.Filters;
+using Umbraco.Core;
+using Umbraco.Core.Exceptions;
+using Umbraco.Core.Services;
+using Umbraco.Web.Composing;
+
+namespace Umbraco.Web.WebApi
+{
+
+    public class LockTimeoutExceptionHandlerAttribute : FilterAttribute, IExceptionFilter
+    {
+        private readonly ILocalizedTextService _localizedTextService;
+
+        public LockTimeoutExceptionHandlerAttribute()
+        {
+            _localizedTextService = Current.Factory.GetInstance<ILocalizedTextService>();
+        }
+
+        public Task ExecuteExceptionFilterAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)
+        {
+            if (actionExecutedContext.Exception is LockTimeoutException timeoutException)
+            {
+                var reason = _localizedTextService.LocalizeLockReason(timeoutException.Reason);
+                actionExecutedContext.Response = actionExecutedContext.Request.CreateResponse(HttpStatusCode.Conflict, reason);
+            }
+            return Task.CompletedTask;
+        }
+    }
+}

src/Umbraco.Web/WebApi/UmbracoAuthorizedApiController.cs

@@ -25,6 +25,7 @@ namespace Umbraco.Web.WebApi
     [UmbracoWebApiRequireHttps]
     [CheckIfUserTicketDataIsStale]
     [UnhandedExceptionLoggerConfiguration]
+    [LockTimeoutExceptionHandler]
     [EnableDetailedErrors]
     public abstract class UmbracoAuthorizedApiController : UmbracoApiController
     {