Fix a bug concerning TCP port release

Commit f396ad8 returns the TCP port used by DRBD disk back to the
TCP/UDP port pool using AddTcpUdpPort().

However, AddTcpUdpPort() writes the config on every invocation,
using _WriteConfig(). This causes two problems:

 * it causes critical errors logged by VerifyConfig(), after the DRBD
   disk removal, and until the actual instance removal.
 * if the code following AddTcpUdpPort() fails, the port is already
   returned back the pool, which causes the port to have duplicates
   (inconsistent config).

AddTcpUdpPort() is invoked in three cases:

 * during InstanceRemove() through _RemoveDisks().
 * during InstanceSetParams() in case of disk removal.
 * during InstanceSetParams() through _ConvertDrbdToPlain().

This commit fixes the problem by removing the _WriteConfig() call from
AddTcpUdpPort(), delegate it to Update() via the
TemporaryReservationManager and ensure AddTcpUdpPort() precedes
Update().

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
[iustin@google.com: small comments adjustements]
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 51a8176..02f1f51 100644 (file)
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -1,7 +1,7 @@
 #
 #
 
-# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Google Inc.
+# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -11132,6 +11132,12 @@ class LUInstanceSetParams(LogicalUnit):
       child.size = parent.size
       child.mode = parent.mode
 
+    # this is a DRBD disk, return its port to the pool
+    # NOTE: this must be done right before the call to cfg.Update!
+    for disk in old_disks:
+      tcp_port = disk.logical_id[2]
+      self.cfg.AddTcpUdpPort(tcp_port)
+
     # update instance structure
     instance.disks = new_disks
     instance.disk_template = constants.DT_PLAIN
@@ -11154,10 +11160,6 @@ class LUInstanceSetParams(LogicalUnit):
         self.LogWarning("Could not remove metadata for disk %d on node %s,"
                         " continuing anyway: %s", idx, pnode, msg)
 
-    # this is a DRBD disk, return its port to the pool
-    for disk in old_disks:
-      tcp_port = disk.logical_id[2]
-      self.cfg.AddTcpUdpPort(tcp_port)
 
   def Exec(self, feedback_fn):
     """Modifies an instance.

diff --git a/lib/config.py b/lib/config.py
index b61d963..d71e01a 100644 (file)
--- a/lib/config.py
+++ b/lib/config.py
@@ -1,7 +1,7 @@
 #
 #
 
-# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Google Inc.
+# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -654,12 +654,15 @@ class ConfigWriter:
   def AddTcpUdpPort(self, port):
     """Adds a new port to the available port pool.
 
+    @warning: this method does not "flush" the configuration (via
+        L{_WriteConfig}); callers should do that themselves once the
+        configuration is stable
+
     """
     if not isinstance(port, int):
       raise errors.ProgrammerError("Invalid type passed for port")
 
     self._config_data.cluster.tcpudp_port_pool.add(port)
-    self._WriteConfig()
 
   @locking.ssynchronized(_config_lock, shared=1)
   def GetPortList(self):