fix for issue 2150 : ConcurrentModificationException in InitializeTask

gbellato

27.31.2007 25dac9c266bda7e12badf795984da0cfcf2dff41

fix for issue 2150  : ConcurrentModificationException in InitializeTask

The updates done to the task entry during an initialize task was 
sometime causing ConcurrentModificationException because they 
were done in an internal thread that can be in concurrence
with the operation threads.

The fix is to use the taskScheduler lock when updating the task entry

 opends/src/server/org/opends/server/backends/task/Task.java

@@ -53,6 +53,8 @@
import org.opends.server.types.DirectoryException;
import org.opends.server.types.DN;
import org.opends.server.types.Entry;
import org.opends.server.types.Modification;
import org.opends.server.types.ModificationType;


import org.opends.server.types.InitializationException;
@@ -594,6 +596,46 @@
    }
  }

  /**
   * Replaces an attribute values of the task entry.
   *
   * @param  name  The name of the attribute that must be replaced.
   *
   * @param  value The value that must replace the previous values of the
   *               attribute.
   *
   * @throws DirectoryException When an error occurs.
   */
  protected void replaceAttributeValue(String name, String value)
  throws DirectoryException
  {
    // We only need to grab the entry-level lock if we don't already hold the
    // broader scheduler lock.
    boolean needLock = (! taskScheduler.holdsSchedulerLock());
    Lock lock = null;
    if (needLock)
    {
      lock = taskScheduler.writeLockEntry(taskEntryDN);
    }

    try
    {
      Entry taskEntry = getTaskEntry();

      ArrayList<Modification> modifications = new ArrayList<Modification>();
      modifications.add(new Modification(ModificationType.REPLACE,
          new Attribute(name, value)));

      taskEntry.applyModifications(modifications);
    }
    finally
    {
      if (needLock)
      {
        taskScheduler.unlockEntry(taskEntryDN, lock);
      }
    }
  }


  /**

 opends/src/server/org/opends/server/tasks/InitializeTask.java

@@ -25,29 +25,24 @@
 *      Portions Copyright 2006-2007 Sun Microsystems, Inc.
 */
package org.opends.server.tasks;
import org.opends.messages.MessageBuilder;

import static org.opends.server.config.ConfigConstants.*;
import static org.opends.server.core.DirectoryServer.getAttributeType;
import static org.opends.server.loggers.debug.DebugLogger.*;
import org.opends.server.loggers.debug.DebugTracer;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import static org.opends.server.loggers.debug.DebugLogger.debugEnabled;
import static org.opends.server.loggers.debug.DebugLogger.getTracer;

import java.util.List;

import org.opends.messages.MessageBuilder;
import org.opends.messages.TaskMessages;
import org.opends.server.backends.task.Task;
import org.opends.server.backends.task.TaskState;
import org.opends.messages.TaskMessages;
import org.opends.server.protocols.asn1.ASN1OctetString;
import org.opends.server.loggers.debug.DebugTracer;
import org.opends.server.replication.plugin.ReplicationDomain;
import org.opends.server.types.Attribute;
import org.opends.server.types.AttributeType;
import org.opends.server.types.AttributeValue;
import org.opends.server.types.DN;
import org.opends.server.types.DirectoryException;
import org.opends.server.types.Entry;
import org.opends.server.types.Modification;
import org.opends.server.types.ModificationType;
import org.opends.server.types.ResultCode;

/**
@@ -122,8 +117,8 @@
    String sourceString = TaskUtils.getSingleValueString(attrList);
    source = domain.decodeSource(sourceString);

    createAttribute(ATTR_TASK_INITIALIZE_LEFT, 0);
    createAttribute(ATTR_TASK_INITIALIZE_DONE, 0);
    replaceAttributeValue(ATTR_TASK_INITIALIZE_LEFT, String.valueOf(0));
    replaceAttributeValue(ATTR_TASK_INITIALIZE_DONE, String.valueOf(0));
  }

  /**
@@ -148,12 +143,15 @@
        while (initState == TaskState.RUNNING)
        {
          initState.wait(1000);
          updateAttribute(ATTR_TASK_INITIALIZE_LEFT, left);
          updateAttribute(ATTR_TASK_INITIALIZE_DONE, total-left);
          replaceAttributeValue(
              ATTR_TASK_INITIALIZE_LEFT, String.valueOf(left));
          replaceAttributeValue(
              ATTR_TASK_INITIALIZE_DONE, String.valueOf(total-left));
        }
      }
      updateAttribute(ATTR_TASK_INITIALIZE_LEFT, left);
      updateAttribute(ATTR_TASK_INITIALIZE_DONE, total-left);
      replaceAttributeValue(ATTR_TASK_INITIALIZE_LEFT, String.valueOf(left));
      replaceAttributeValue(
          ATTR_TASK_INITIALIZE_DONE, String.valueOf(total-left));
    }
    catch(InterruptedException ie) {}
    catch(DirectoryException de)
@@ -199,50 +197,6 @@
    {}
  }

  /**
   * Create a new attribute the task entry.
   * @param name The name of the attribute
   * @param value The value to store
   */
  protected void createAttribute(String name, long value)
  {
    AttributeType type;
    LinkedHashSet<AttributeValue> values =
      new LinkedHashSet<AttributeValue>();

    Entry taskEntry = getTaskEntry();
    try
    {
      type = getAttributeType(name, true);
      values.add(new AttributeValue(type,
          new ASN1OctetString(String.valueOf(value))));
      ArrayList<Attribute> attrList = new ArrayList<Attribute>(1);
      attrList.add(new Attribute(type, name,values));
      taskEntry.putAttribute(type, attrList);
    }
    finally
    {
      // taskScheduler.unlockEntry(taskEntryDN, lock);
    }
  }

  /**
   * Update an attribute for this task.
   * @param name The name of the attribute.
   * @param value The value.
   * @throws DirectoryException When an error occurs.
   */
  protected void updateAttribute(String name, long value)
  throws DirectoryException
  {
    Entry taskEntry = getTaskEntry();

    ArrayList<Modification> modifications = new ArrayList<Modification>();
    modifications.add(new Modification(ModificationType.REPLACE,
        new Attribute(name, String.valueOf(value))));

    taskEntry.applyModifications(modifications);
  }

  /**
   * Set the total number of entries expected to be imported.