Get rid of the data socket completely when data transfer is finished.

net/ftp/ftp_network_transaction.cc

 // Copyright (c) 2008 The Chromium Authors. All rights reserved.  Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
 #include "net/ftp/ftp_network_transaction.h"
 
 #include "base/compiler_specific.h"
 #include "base/string_util.h"
 #include "net/base/connection_type_histograms.h"
 #include "net/base/load_log.h"
@@ skipping 963 matching lines @@
     next_state_ = STATE_CTRL_WRITE_SIZE;
   }
   return OK;
 }
 
 int FtpNetworkTransaction::DoDataRead() {
   DCHECK(read_data_buf_);
   DCHECK_GT(read_data_buf_len_, 0);
 
   if (data_socket_ == NULL || !data_socket_->IsConnected()) {
+    // If we don't destroy the data socket completely, some servers will wait

[wtc, 2009/09/09 20:20:42]

It would be nice to explain that a half-closed TCP connection
still needs to be closed on our side.

+    // for us (http://crbug.com/21127).
+    data_socket_.reset();
+
     // No more data so send QUIT Command now and wait for response.
     return Stop(OK);
   }
 
   next_state_ = STATE_DATA_READ_COMPLETE;
   read_data_buf_->data()[0] = 0;
   return data_socket_->Read(read_data_buf_, read_data_buf_len_,
                             &io_callback_);
 }
 
 int FtpNetworkTransaction::DoDataReadComplete(int result) {
   return result;
 }
 
 }  // namespace net