diff --git a/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageHandlerImpl.java b/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageHandlerImpl.java
index 98df88fc..a534d899 100644
--- a/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageHandlerImpl.java
+++ b/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageHandlerImpl.java
@@ -304,7 +304,7 @@ public ChannelEntity createChannel ( final String name, final String description
         return channel;
     }
 
-    public void setProvidedMetaData ( final ChannelEntity channel, final Map<MetaKey, String> providedMetaData )
+    protected void setProvidedMetaData ( final ChannelEntity channel, final Map<MetaKey, String> providedMetaData )
     {
         if ( providedMetaData == null )
         {
@@ -329,20 +329,22 @@ public void setProvidedMetaData ( final ChannelEntity channel, final Map<MetaKey
     @Override
     public void updateChannel ( final String channelId, final String name, final String description )
     {
-        final ChannelEntity channel = getCheckedChannel ( channelId );
+        this.lockManager.modifyRun ( channelId, () -> {
+            final ChannelEntity channel = getCheckedChannel ( channelId );
 
-        if ( "".equals ( name ) )
-        {
-            channel.setName ( null );
-        }
-        else
-        {
-            channel.setName ( name );
-        }
+            if ( "".equals ( name ) )
+            {
+                channel.setName ( null );
+            }
+            else
+            {
+                channel.setName ( name );
+            }
 
-        channel.setDescription ( description );
+            channel.setDescription ( description );
 
-        this.em.persist ( channel );
+            this.em.persist ( channel );
+        } );
     }
 
     @Override
@@ -698,8 +700,10 @@ public void generateArtifact ( final String id )
 
             testLocked ( ae.getChannel () );
 
-            regenerateArtifact ( (GeneratorArtifactEntity)ae, false );
-            runChannelAggregators ( ae.getChannel () );
+            this.lockManager.modifyRun ( ae.getChannel ().getId (), () -> {
+                regenerateArtifact ( (GeneratorArtifactEntity)ae, false );
+                runChannelAggregators ( ae.getChannel () );
+            } );
         }
         catch ( final Exception e )
         {
@@ -719,28 +723,32 @@ public ArtifactInformation deleteArtifact ( final String artifactId )
 
         testLocked ( ae.getChannel () );
 
-        if ( !isDeleteable ( ae ) )
-        {
-            throw new IllegalStateException ( String.format ( "Unable to delete artifact %s (%s). Artifact might be virtual or generated.", ae.getName (), ae.getId () ) );
-        }
+        return this.lockManager.modifyCall ( ae.getChannel ().getId (), () -> {
 
-        final SortedMap<MetaKey, String> md = convertMetaData ( ae );
+            if ( !isDeleteable ( ae ) )
+            {
+                throw new IllegalStateException ( String.format ( "Unable to delete artifact %s (%s). Artifact might be virtual or generated.", ae.getName (), ae.getId () ) );
+            }
 
-        this.em.remove ( ae );
-        this.em.flush ();
+            final SortedMap<MetaKey, String> md = convertMetaData ( ae );
 
-        logger.info ( "Artifact deleted: {}", artifactId );
+            this.em.remove ( ae );
+            this.em.flush ();
 
-        final ChannelEntity channel = ae.getChannel ();
+            logger.info ( "Artifact deleted: {}", artifactId );
 
-        final RegenerateTracker tracker = new RegenerateTracker ();
-        runGeneratorTriggers ( tracker, channel, new RemovedEvent ( ae.getId (), md ) );
-        tracker.process ( this );
+            final ChannelEntity channel = ae.getChannel ();
 
-        // now run the channel aggregator
-        runChannelAggregators ( channel );
+            final RegenerateTracker tracker = new RegenerateTracker ();
+            runGeneratorTriggers ( tracker, channel, new RemovedEvent ( ae.getId (), md ) );
+            tracker.process ( this );
+
+            // now run the channel aggregator
+            runChannelAggregators ( channel );
+
+            return convert ( ae, null );
 
-        return convert ( ae, null );
+        } );
     }
 
     private void runGeneratorTriggers ( final RegenerateTracker tracker, final ChannelEntity channel, final Object event )
@@ -1366,16 +1374,18 @@ public SortedMap<MetaKey, String> getChannelProvidedMetaData ( final String chan
 
     public void clearChannel ( final String channelId )
     {
-        final ChannelEntity channel = getCheckedChannel ( channelId );
+        this.lockManager.modifyRun ( channelId, () -> {
+            final ChannelEntity channel = getCheckedChannel ( channelId );
 
-        testLocked ( channel );
+            testLocked ( channel );
 
-        // processing by "clear" triggers the entity listeners
+            // processing by "clear" triggers the entity listeners
 
-        channel.getArtifacts ().clear ();
-        this.em.persist ( channel );
+            channel.getArtifacts ().clear ();
+            this.em.persist ( channel );
 
-        runChannelAggregators ( channel );
+            runChannelAggregators ( channel );
+        } );
     }
 
     private static Set<String> expandDependencies ( final Set<String> aspects )
diff --git a/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageServiceImpl.java b/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageServiceImpl.java
index 88d20dfb..7c3889cd 100644
--- a/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageServiceImpl.java
+++ b/de.dentrassi.pm.storage.service.jpa/src/de/dentrassi/pm/storage/service/jpa/StorageServiceImpl.java
@@ -557,40 +557,43 @@ public Map<MetaKey, String> applyMetaData ( final String artifactId, final Map<M
 
             testLocked ( artifact.getChannel () );
 
-            final Map<MetaKey, String> result = convert ( artifact.getProvidedProperties () );
+            return this.lockManager.modifyCall ( artifact.getChannel ().getId (), () -> {
 
-            // merge
+                final Map<MetaKey, String> result = convert ( artifact.getProvidedProperties () );
 
-            mergeMetaData ( metadata, result );
+                // merge
 
-            // first clear all
+                mergeMetaData ( metadata, result );
 
-            artifact.getProvidedProperties ().clear ();
+                // first clear all
 
-            em.persist ( artifact );
-            em.flush ();
+                artifact.getProvidedProperties ().clear ();
 
-            // now add the new set
+                em.persist ( artifact );
+                em.flush ();
 
-            Helper.convertProvidedProperties ( result, artifact, artifact.getProvidedProperties () );
+                // now add the new set
 
-            // store
+                Helper.convertProvidedProperties ( result, artifact, artifact.getProvidedProperties () );
 
-            em.persist ( artifact );
-            em.flush ();
+                // store
 
-            // recreate virtual artifacts
+                em.persist ( artifact );
+                em.flush ();
 
-            hi.recreateVirtualArtifacts ( artifact );
+                // recreate virtual artifacts
 
-            // recreate generated artifacts
+                hi.recreateVirtualArtifacts ( artifact );
 
-            if ( artifact instanceof GeneratorArtifactEntity )
-            {
-                hi.regenerateArtifact ( (GeneratorArtifactEntity)artifact, true );
-            }
+                // recreate generated artifacts
 
-            return result;
+                if ( artifact instanceof GeneratorArtifactEntity )
+                {
+                    hi.regenerateArtifact ( (GeneratorArtifactEntity)artifact, true );
+                }
+
+                return result;
+            } );
         } );
     }
 
@@ -700,9 +703,7 @@ public List<Artifact> findByName ( final String channelId, final String artifact
     public void clearChannel ( final String channelId )
     {
         this.lockManager.modifyRun ( channelId, () -> {
-
             doWithHandlerVoid ( hi -> hi.clearChannel ( channelId ) );
-
         } );
     }
 
@@ -753,30 +754,34 @@ public Collection<DeployGroup> getDeployGroups ( final String channelId )
 
     public void addDeployGroup ( final String channelId, final String groupId )
     {
-        doWithTransactionVoid ( ( em ) -> {
-            final ChannelEntity channel = getCheckedChannel ( em, channelId );
-            final DeployGroupEntity group = DeployAuthServiceImpl.getGroupChecked ( em, groupId );
-            channel.getDeployGroups ().add ( group );
-            em.persist ( channel );
+        this.lockManager.modifyRun ( channelId, () -> {
+            doWithTransactionVoid ( ( em ) -> {
+                final ChannelEntity channel = getCheckedChannel ( em, channelId );
+                final DeployGroupEntity group = DeployAuthServiceImpl.getGroupChecked ( em, groupId );
+                channel.getDeployGroups ().add ( group );
+                em.persist ( channel );
+            } );
         } );
     }
 
     public void removeDeployGroup ( final String channelId, final String groupId )
     {
-        doWithTransactionVoid ( ( em ) -> {
-            final ChannelEntity channel = getCheckedChannel ( em, channelId );
+        this.lockManager.modifyRun ( channelId, () -> {
+            doWithTransactionVoid ( ( em ) -> {
+                final ChannelEntity channel = getCheckedChannel ( em, channelId );
 
-            final Iterator<DeployGroupEntity> i = channel.getDeployGroups ().iterator ();
-            while ( i.hasNext () )
-            {
-                final DeployGroupEntity dg = i.next ();
-                if ( dg.getId ().equals ( groupId ) )
+                final Iterator<DeployGroupEntity> i = channel.getDeployGroups ().iterator ();
+                while ( i.hasNext () )
                 {
-                    i.remove ();
+                    final DeployGroupEntity dg = i.next ();
+                    if ( dg.getId ().equals ( groupId ) )
+                    {
+                        i.remove ();
+                    }
                 }
-            }
 
-            em.persist ( channel );
+                em.persist ( channel );
+            } );
         } );
     }