Method create

src/mds/MDLog.cc:267–304

}

void MDLog::create(MDSContext *c)
{
  ceph_assert(ceph_mutex_is_locked_by_me(mds->mds_lock));

  dout(5) << "create empty log" << dendl;

  C_GatherBuilder gather(g_ceph_context);
  // This requires an OnFinisher wrapper because Journaler will call back the completion for write_head inside its own lock
  // XXX but should maybe that be handled inside Journaler?
  gather.set_finisher(new C_IO_Wrapper(mds, c));

  // The inode of the default Journaler we will create
  ino = MDS_INO_LOG_OFFSET + mds->get_nodeid();

  // Instantiate Journaler and start async write to RADOS
  ceph_assert(journaler == NULL);
  journaler = new Journaler("mdlog", ino, mds->get_metadata_pool(),
                            CEPH_FS_ONDISK_MAGIC, mds->objecter, logger,
                            l_mdl_jlat, mds->finisher);
  ceph_assert(journaler->is_readonly());
  journaler->set_write_error_handler(new C_MDL_WriteError(this));
  journaler->set_writeable();
  journaler->create(&mds->mdcache->default_log_layout, g_conf()->mds_journal_format);
  journaler->write_head(gather.new_sub());

  // Async write JournalPointer to RADOS
  JournalPointer jp(mds->get_nodeid(), mds->get_metadata_pool());
  jp.front = ino;
  jp.back = 0;
  jp.save(mds->objecter, gather.new_sub());

  gather.activate();

  logger->set(l_mdl_expos, journaler->get_expire_pos());
  logger->set(l_mdl_wrpos, journaler->get_write_pos());

  submit_thread.create("mds-log-submit");
}

void MDLog::open(MDSContext *c)
{