Add stricter checks for OpInstanceSetParams.{nics,disks}

[ganeti-local] / lib / locking.py

diff --git a/lib/locking.py b/lib/locking.py
index 772c8f1..5ac20f9 100644 (file)
--- a/lib/locking.py
+++ b/lib/locking.py
@@ -1,7 +1,7 @@
 #
 #
 
 #
 #
 

-# Copyright (C) 2006, 2007, 2008, 2009, 2010 Google Inc.
+# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 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
 #
 # 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

@@ -20,7 +20,7 @@
 
 """Module implementing the Ganeti locking code."""
 
 
 """Module implementing the Ganeti locking code."""
 

-# pylint: disable-msg=W0212
+# pylint: disable=W0212

 
 # W0212 since e.g. LockSet methods use (a lot) the internals of
 # SharedLock
 
 # W0212 since e.g. LockSet methods use (a lot) the internals of
 # SharedLock

@@ -32,7 +32,6 @@ import errno
 import weakref
 import logging
 import heapq
 import weakref
 import logging
 import heapq

-import operator

 import itertools
 
 from ganeti import errors
 import itertools
 
 from ganeti import errors

@@ -162,7 +161,7 @@ class _BaseCondition(object):
     except AttributeError:
       self._acquire_restore = self._base_acquire_restore
     try:
     except AttributeError:
       self._acquire_restore = self._base_acquire_restore
     try:

-      self._is_owned = lock._is_owned
+      self._is_owned = lock.is_owned

     except AttributeError:
       self._is_owned = self._base_is_owned
 
     except AttributeError:
       self._is_owned = self._base_is_owned
 

@@ -277,7 +276,7 @@ class SingleNotifyPipeCondition(_BaseCondition):
       if self._nwaiters == 0:
         self._Cleanup()
 
       if self._nwaiters == 0:
         self._Cleanup()
 

-  def notifyAll(self): # pylint: disable-msg=C0103
+  def notifyAll(self): # pylint: disable=C0103

     """Close the writing side of the pipe to notify all waiters.
 
     """
     """Close the writing side of the pipe to notify all waiters.
 
     """

@@ -334,7 +333,7 @@ class PipeCondition(_BaseCondition):
       self._check_owned()
       self._waiters.remove(threading.currentThread())
 
       self._check_owned()
       self._waiters.remove(threading.currentThread())
 

-  def notifyAll(self): # pylint: disable-msg=C0103
+  def notifyAll(self): # pylint: disable=C0103

     """Notify all currently waiting threads.
 
     """
     """Notify all currently waiting threads.
 
     """

@@ -358,6 +357,11 @@ class PipeCondition(_BaseCondition):
 
     return bool(self._waiters)
 
 
     return bool(self._waiters)
 

+  def __repr__(self):
+    return ("<%s.%s waiters=%s at %#x>" %
+            (self.__class__.__module__, self.__class__.__name__,
+             self._waiters, id(self)))
+

 
 class _PipeConditionWithMode(PipeCondition):
   __slots__ = [
 
 class _PipeConditionWithMode(PipeCondition):
   __slots__ = [

@@ -434,9 +438,15 @@ class SharedLock(object):
 
     # Register with lock monitor
     if monitor:
 
     # Register with lock monitor
     if monitor:

+      logging.debug("Adding lock %s to monitor", name)

       monitor.RegisterLock(self)
 
       monitor.RegisterLock(self)
 

-  def GetInfo(self, requested):
+  def __repr__(self):
+    return ("<%s.%s name=%s at %#x>" %
+            (self.__class__.__module__, self.__class__.__name__,
+             self.name, id(self)))
+
+  def GetLockInfo(self, requested):

     """Retrieves information for querying locks.
 
     @type requested: set
     """Retrieves information for querying locks.
 
     @type requested: set

@@ -489,7 +499,7 @@ class SharedLock(object):
       else:
         pending = None
 
       else:
         pending = None
 

-      return (self.name, mode, owner_names, pending)
+      return [(self.name, mode, owner_names, pending)]

     finally:
       self.__lock.release()
 
     finally:
       self.__lock.release()
 

@@ -526,7 +536,7 @@ class SharedLock(object):
     else:
       return self.__is_exclusive()
 
     else:
       return self.__is_exclusive()
 

-  def _is_owned(self, shared=-1):
+  def is_owned(self, shared=-1):

     """Is the current thread somehow owning the lock at this time?
 
     @param shared:
     """Is the current thread somehow owning the lock at this time?
 
     @param shared:

@@ -541,6 +551,10 @@ class SharedLock(object):
     finally:
       self.__lock.release()
 
     finally:
       self.__lock.release()
 

+  #: Necessary to remain compatible with threading.Condition, which tries to
+  #: retrieve a locks' "_is_owned" attribute
+  _is_owned = is_owned
+

   def _count_pending(self):
     """Returns the number of pending acquires.
 
   def _count_pending(self):
     """Returns the number of pending acquires.
 

@@ -938,17 +952,53 @@ class LockSet:
     """
     return self.__lockdict
 
     """
     return self.__lockdict
 

-  def _is_owned(self):
-    """Is the current thread a current level owner?"""
+  def is_owned(self):
+    """Is the current thread a current level owner?
+
+    @note: Use L{check_owned} to check if a specific lock is held
+
+    """

     return threading.currentThread() in self.__owners
 
     return threading.currentThread() in self.__owners
 

+  def check_owned(self, names, shared=-1):
+    """Check if locks are owned in a specific mode.
+
+    @type names: sequence or string
+    @param names: Lock names (or a single lock name)
+    @param shared: See L{SharedLock.is_owned}
+    @rtype: bool
+    @note: Use L{is_owned} to check if the current thread holds I{any} lock and
+      L{list_owned} to get the names of all owned locks
+
+    """
+    if isinstance(names, basestring):
+      names = [names]
+
+    # Avoid check if no locks are owned anyway
+    if names and self.is_owned():
+      candidates = []
+
+      # Gather references to all locks (in case they're deleted in the meantime)
+      for lname in names:
+        try:
+          lock = self.__lockdict[lname]
+        except KeyError:
+          raise errors.LockError("Non-existing lock '%s' in set '%s' (it may"
+                                 " have been removed)" % (lname, self.name))
+        else:
+          candidates.append(lock)
+
+      return compat.all(lock.is_owned(shared=shared) for lock in candidates)
+    else:
+      return False
+

   def _add_owned(self, name=None):
     """Note the current thread owns the given lock"""
     if name is None:
   def _add_owned(self, name=None):
     """Note the current thread owns the given lock"""
     if name is None:

-      if not self._is_owned():
+      if not self.is_owned():

         self.__owners[threading.currentThread()] = set()
     else:
         self.__owners[threading.currentThread()] = set()
     else:

-      if self._is_owned():
+      if self.is_owned():

         self.__owners[threading.currentThread()].add(name)
       else:
         self.__owners[threading.currentThread()] = set([name])
         self.__owners[threading.currentThread()].add(name)
       else:
         self.__owners[threading.currentThread()] = set([name])

@@ -956,29 +1006,29 @@ class LockSet:
   def _del_owned(self, name=None):
     """Note the current thread owns the given lock"""
 
   def _del_owned(self, name=None):
     """Note the current thread owns the given lock"""
 

-    assert not (name is None and self.__lock._is_owned()), \
+    assert not (name is None and self.__lock.is_owned()), \

            "Cannot hold internal lock when deleting owner status"
 
     if name is not None:
       self.__owners[threading.currentThread()].remove(name)
 
     # Only remove the key if we don't hold the set-lock as well
            "Cannot hold internal lock when deleting owner status"
 
     if name is not None:
       self.__owners[threading.currentThread()].remove(name)
 
     # Only remove the key if we don't hold the set-lock as well

-    if (not self.__lock._is_owned() and
+    if (not self.__lock.is_owned() and

         not self.__owners[threading.currentThread()]):
       del self.__owners[threading.currentThread()]
 
         not self.__owners[threading.currentThread()]):
       del self.__owners[threading.currentThread()]
 

-  def _list_owned(self):
+  def list_owned(self):

     """Get the set of resource names owned by the current thread"""
     """Get the set of resource names owned by the current thread"""

-    if self._is_owned():
+    if self.is_owned():

       return self.__owners[threading.currentThread()].copy()
     else:
       return set()
 
   def _release_and_delete_owned(self):
     """Release and delete all resources owned by the current thread"""
       return self.__owners[threading.currentThread()].copy()
     else:
       return set()
 
   def _release_and_delete_owned(self):
     """Release and delete all resources owned by the current thread"""

-    for lname in self._list_owned():
+    for lname in self.list_owned():

       lock = self.__lockdict[lname]
       lock = self.__lockdict[lname]

-      if lock._is_owned():
+      if lock.is_owned():

         lock.release()
       self._del_owned(name=lname)
 
         lock.release()
       self._del_owned(name=lname)
 

@@ -1000,7 +1050,7 @@ class LockSet:
     # If we don't already own the set-level lock acquired
     # we'll get it and note we need to release it later.
     release_lock = False
     # If we don't already own the set-level lock acquired
     # we'll get it and note we need to release it later.
     release_lock = False

-    if not self.__lock._is_owned():
+    if not self.__lock.is_owned():

       release_lock = True
       self.__lock.acquire(shared=1)
     try:
       release_lock = True
       self.__lock.acquire(shared=1)
     try:

@@ -1037,8 +1087,8 @@ class LockSet:
     assert timeout is None or timeout >= 0.0
 
     # Check we don't already own locks at this level
     assert timeout is None or timeout >= 0.0
 
     # Check we don't already own locks at this level

-    assert not self._is_owned(), ("Cannot acquire locks in the same set twice"
-                                  " (lockset %s)" % self.name)
+    assert not self.is_owned(), ("Cannot acquire locks in the same set twice"
+                                 " (lockset %s)" % self.name)

 
     if priority is None:
       priority = _DEFAULT_PRIORITY
 
     if priority is None:
       priority = _DEFAULT_PRIORITY

@@ -1168,7 +1218,7 @@ class LockSet:
           # We shouldn't have problems adding the lock to the owners list, but
           # if we did we'll try to release this lock and re-raise exception.
           # Of course something is going to be really wrong after this.
           # We shouldn't have problems adding the lock to the owners list, but
           # if we did we'll try to release this lock and re-raise exception.
           # Of course something is going to be really wrong after this.

-          if lock._is_owned():
+          if lock.is_owned():

             lock.release()
           raise
 
             lock.release()
           raise
 

@@ -1185,14 +1235,14 @@ class LockSet:
     The locks must have been acquired in exclusive mode.
 
     """
     The locks must have been acquired in exclusive mode.
 
     """

-    assert self._is_owned(), ("downgrade on lockset %s while not owning any"
-                              " lock" % self.name)
+    assert self.is_owned(), ("downgrade on lockset %s while not owning any"
+                             " lock" % self.name)

 
     # Support passing in a single resource to downgrade rather than many
     if isinstance(names, basestring):
       names = [names]
 
 
     # Support passing in a single resource to downgrade rather than many
     if isinstance(names, basestring):
       names = [names]
 

-    owned = self._list_owned()
+    owned = self.list_owned()

 
     if names is None:
       names = owned
 
     if names is None:
       names = owned

@@ -1206,12 +1256,12 @@ class LockSet:
       self.__lockdict[lockname].downgrade()
 
     # Do we own the lockset in exclusive mode?
       self.__lockdict[lockname].downgrade()
 
     # Do we own the lockset in exclusive mode?

-    if self.__lock._is_owned(shared=0):
+    if self.__lock.is_owned(shared=0):

       # Have all locks been downgraded?
       # Have all locks been downgraded?

-      if not compat.any(lock._is_owned(shared=0)
+      if not compat.any(lock.is_owned(shared=0)

                         for lock in self.__lockdict.values()):
         self.__lock.downgrade()
                         for lock in self.__lockdict.values()):
         self.__lock.downgrade()

-        assert self.__lock._is_owned(shared=1)
+        assert self.__lock.is_owned(shared=1)

 
     return True
 
 
     return True
 

@@ -1226,24 +1276,24 @@ class LockSet:
         (defaults to all the locks acquired at that level).
 
     """
         (defaults to all the locks acquired at that level).
 
     """

-    assert self._is_owned(), ("release() on lock set %s while not owner" %
-                              self.name)
+    assert self.is_owned(), ("release() on lock set %s while not owner" %
+                             self.name)

 
     # Support passing in a single resource to release rather than many
     if isinstance(names, basestring):
       names = [names]
 
     if names is None:
 
     # Support passing in a single resource to release rather than many
     if isinstance(names, basestring):
       names = [names]
 
     if names is None:

-      names = self._list_owned()
+      names = self.list_owned()

     else:
       names = set(names)
     else:
       names = set(names)

-      assert self._list_owned().issuperset(names), (
+      assert self.list_owned().issuperset(names), (

                "release() on unheld resources %s (set %s)" %
                "release() on unheld resources %s (set %s)" %

-               (names.difference(self._list_owned()), self.name))
+               (names.difference(self.list_owned()), self.name))

 
     # First of all let's release the "all elements" lock, if set.
     # After this 'add' can work again
 
     # First of all let's release the "all elements" lock, if set.
     # After this 'add' can work again

-    if self.__lock._is_owned():
+    if self.__lock.is_owned():

       self.__lock.release()
       self._del_owned()
 
       self.__lock.release()
       self._del_owned()
 

@@ -1265,7 +1315,7 @@ class LockSet:
 
     """
     # Check we don't already own locks at this level
 
     """
     # Check we don't already own locks at this level

-    assert not self._is_owned() or self.__lock._is_owned(shared=0), \
+    assert not self.is_owned() or self.__lock.is_owned(shared=0), \

       ("Cannot add locks if the set %s is only partially owned, or shared" %
        self.name)
 
       ("Cannot add locks if the set %s is only partially owned, or shared" %
        self.name)
 

@@ -1276,7 +1326,7 @@ class LockSet:
     # If we don't already own the set-level lock acquired in an exclusive way
     # we'll get it and note we need to release it later.
     release_lock = False
     # If we don't already own the set-level lock acquired in an exclusive way
     # we'll get it and note we need to release it later.
     release_lock = False

-    if not self.__lock._is_owned():
+    if not self.__lock.is_owned():

       release_lock = True
       self.__lock.acquire()
 
       release_lock = True
       self.__lock.acquire()
 

@@ -1339,7 +1389,7 @@ class LockSet:
     # If we own any subset of this lock it must be a superset of what we want
     # to delete. The ownership must also be exclusive, but that will be checked
     # by the lock itself.
     # If we own any subset of this lock it must be a superset of what we want
     # to delete. The ownership must also be exclusive, but that will be checked
     # by the lock itself.

-    assert not self._is_owned() or self._list_owned().issuperset(names), (
+    assert not self.is_owned() or self.list_owned().issuperset(names), (

       "remove() on acquired lockset %s while not owning all elements" %
       self.name)
 
       "remove() on acquired lockset %s while not owning all elements" %
       self.name)
 

@@ -1356,8 +1406,8 @@ class LockSet:
         removed.append(lname)
       except (KeyError, errors.LockError):
         # This cannot happen if we were already holding it, verify:
         removed.append(lname)
       except (KeyError, errors.LockError):
         # This cannot happen if we were already holding it, verify:

-        assert not self._is_owned(), ("remove failed while holding lockset %s"
-                                      % self.name)
+        assert not self.is_owned(), ("remove failed while holding lockset %s" %
+                                     self.name)

       else:
         # If no LockError was raised we are the ones who deleted the lock.
         # This means we can safely remove it from lockdict, as any further or
       else:
         # If no LockError was raised we are the ones who deleted the lock.
         # This means we can safely remove it from lockdict, as any further or

@@ -1368,7 +1418,7 @@ class LockSet:
         # it's the job of the one who actually deleted it.
         del self.__lockdict[lname]
         # And let's remove it from our private list if we owned it.
         # it's the job of the one who actually deleted it.
         del self.__lockdict[lname]
         # And let's remove it from our private list if we owned it.

-        if self._is_owned():
+        if self.is_owned():

           self._del_owned(name=lname)
 
     return removed
           self._del_owned(name=lname)
 
     return removed

@@ -1387,20 +1437,31 @@ LEVEL_CLUSTER = 0
 LEVEL_INSTANCE = 1
 LEVEL_NODEGROUP = 2
 LEVEL_NODE = 3
 LEVEL_INSTANCE = 1
 LEVEL_NODEGROUP = 2
 LEVEL_NODE = 3

+LEVEL_NODE_RES = 4

 
 

-LEVELS = [LEVEL_CLUSTER,
-          LEVEL_INSTANCE,
-          LEVEL_NODEGROUP,
-          LEVEL_NODE]
+LEVELS = [
+  LEVEL_CLUSTER,
+  LEVEL_INSTANCE,
+  LEVEL_NODEGROUP,
+  LEVEL_NODE,
+  LEVEL_NODE_RES,
+  ]

 
 # Lock levels which are modifiable
 
 # Lock levels which are modifiable

-LEVELS_MOD = [LEVEL_NODE, LEVEL_NODEGROUP, LEVEL_INSTANCE]
-
+LEVELS_MOD = frozenset([
+  LEVEL_NODE_RES,
+  LEVEL_NODE,
+  LEVEL_NODEGROUP,
+  LEVEL_INSTANCE,
+  ])
+
+#: Lock level names (make sure to use singular form)

 LEVEL_NAMES = {
   LEVEL_CLUSTER: "cluster",
   LEVEL_INSTANCE: "instance",
   LEVEL_NODEGROUP: "nodegroup",
   LEVEL_NODE: "node",
 LEVEL_NAMES = {
   LEVEL_CLUSTER: "cluster",
   LEVEL_INSTANCE: "instance",
   LEVEL_NODEGROUP: "nodegroup",
   LEVEL_NODE: "node",

+  LEVEL_NODE_RES: "node-res",

   }
 
 # Constant for the big ganeti lock
   }
 
 # Constant for the big ganeti lock

@@ -1439,13 +1500,25 @@ class GanetiLockManager:
     # The keyring contains all the locks, at their level and in the correct
     # locking order.
     self.__keyring = {
     # The keyring contains all the locks, at their level and in the correct
     # locking order.
     self.__keyring = {

-      LEVEL_CLUSTER: LockSet([BGL], "BGL", monitor=self._monitor),
-      LEVEL_NODE: LockSet(nodes, "nodes", monitor=self._monitor),
-      LEVEL_NODEGROUP: LockSet(nodegroups, "nodegroups", monitor=self._monitor),
-      LEVEL_INSTANCE: LockSet(instances, "instances",
+      LEVEL_CLUSTER: LockSet([BGL], "cluster", monitor=self._monitor),
+      LEVEL_NODE: LockSet(nodes, "node", monitor=self._monitor),
+      LEVEL_NODE_RES: LockSet(nodes, "node-res", monitor=self._monitor),
+      LEVEL_NODEGROUP: LockSet(nodegroups, "nodegroup", monitor=self._monitor),
+      LEVEL_INSTANCE: LockSet(instances, "instance",

                               monitor=self._monitor),
       }
 
                               monitor=self._monitor),
       }
 

+    assert compat.all(ls.name == LEVEL_NAMES[level]
+                      for (level, ls) in self.__keyring.items())
+
+  def AddToLockMonitor(self, provider):
+    """Registers a new lock with the monitor.
+
+    See L{LockMonitor.RegisterLock}.
+
+    """
+    return self._monitor.RegisterLock(provider)
+

   def QueryLocks(self, fields):
     """Queries information from all locks.
 
   def QueryLocks(self, fields):
     """Queries information from all locks.
 

@@ -1473,21 +1546,25 @@ class GanetiLockManager:
     assert level in LEVELS, "Invalid locking level %s" % level
     return self.__keyring[level]._names()
 
     assert level in LEVELS, "Invalid locking level %s" % level
     return self.__keyring[level]._names()
 

-  def _is_owned(self, level):
+  def is_owned(self, level):

     """Check whether we are owning locks at the given level
 
     """
     """Check whether we are owning locks at the given level
 
     """

-    return self.__keyring[level]._is_owned()
-
-  is_owned = _is_owned
+    return self.__keyring[level].is_owned()

 
 

-  def _list_owned(self, level):
+  def list_owned(self, level):

     """Get the set of owned locks at the given level
 
     """
     """Get the set of owned locks at the given level
 
     """

-    return self.__keyring[level]._list_owned()
+    return self.__keyring[level].list_owned()

 
 

-  list_owned = _list_owned
+  def check_owned(self, level, names, shared=-1):
+    """Check if locks at a certain level are owned in a specific mode.
+
+    @see: L{LockSet.check_owned}
+
+    """
+    return self.__keyring[level].check_owned(names, shared=shared)

 
   def _upper_owned(self, level):
     """Check that we don't own any lock at a level greater than the given one.
 
   def _upper_owned(self, level):
     """Check that we don't own any lock at a level greater than the given one.

@@ -1495,18 +1572,18 @@ class GanetiLockManager:
     """
     # This way of checking only works if LEVELS[i] = i, which we check for in
     # the test cases.
     """
     # This way of checking only works if LEVELS[i] = i, which we check for in
     # the test cases.

-    return compat.any((self._is_owned(l) for l in LEVELS[level + 1:]))
+    return compat.any((self.is_owned(l) for l in LEVELS[level + 1:]))

 
 

-  def _BGL_owned(self): # pylint: disable-msg=C0103
+  def _BGL_owned(self): # pylint: disable=C0103

     """Check if the current thread owns the BGL.
 
     Both an exclusive or a shared acquisition work.
 
     """
     """Check if the current thread owns the BGL.
 
     Both an exclusive or a shared acquisition work.
 
     """

-    return BGL in self.__keyring[LEVEL_CLUSTER]._list_owned()
+    return BGL in self.__keyring[LEVEL_CLUSTER].list_owned()

 
   @staticmethod
 
   @staticmethod

-  def _contains_BGL(level, names): # pylint: disable-msg=C0103
+  def _contains_BGL(level, names): # pylint: disable=C0103

     """Check if the level contains the BGL.
 
     Check if acting on the given level and set of names will change
     """Check if the level contains the BGL.
 
     Check if acting on the given level and set of names will change

@@ -1585,7 +1662,7 @@ class GanetiLockManager:
             not self._upper_owned(LEVEL_CLUSTER)), (
             "Cannot release the Big Ganeti Lock while holding something"
             " at upper levels (%r)" %
             not self._upper_owned(LEVEL_CLUSTER)), (
             "Cannot release the Big Ganeti Lock while holding something"
             " at upper levels (%r)" %

-            (utils.CommaJoin(["%s=%r" % (LEVEL_NAMES[i], self._list_owned(i))
+            (utils.CommaJoin(["%s=%r" % (LEVEL_NAMES[i], self.list_owned(i))

                               for i in self.__keyring.keys()]), ))
 
     # Release will complain if we don't own the locks already
                               for i in self.__keyring.keys()]), ))
 
     # Release will complain if we don't own the locks already

@@ -1630,21 +1707,23 @@ class GanetiLockManager:
     # Check we either own the level or don't own anything from here
     # up. LockSet.remove() will check the case in which we don't own
     # all the needed resources, or we have a shared ownership.
     # Check we either own the level or don't own anything from here
     # up. LockSet.remove() will check the case in which we don't own
     # all the needed resources, or we have a shared ownership.

-    assert self._is_owned(level) or not self._upper_owned(level), (
+    assert self.is_owned(level) or not self._upper_owned(level), (

            "Cannot remove locks at a level while not owning it or"
            " owning some at a greater one")
     return self.__keyring[level].remove(names)
 
 
            "Cannot remove locks at a level while not owning it or"
            " owning some at a greater one")
     return self.__keyring[level].remove(names)
 
 

-def _MonitorSortKey((num, item)):
+def _MonitorSortKey((item, idx, num)):

   """Sorting key function.
 
   """Sorting key function.
 

-  Sort by name, then by incoming order.
+  Sort by name, registration order and then order of information. This provides
+  a stable sort order over different providers, even if they return the same
+  name.

 
   """
   (name, _, _, _) = item
 
 
   """
   (name, _, _, _) = item
 

-  return (utils.NiceSortKey(name), num)
+  return (utils.NiceSortKey(name), num, idx)

 
 
 class LockMonitor(object):
 
 
 class LockMonitor(object):

@@ -1664,12 +1743,19 @@ class LockMonitor(object):
     self._locks = weakref.WeakKeyDictionary()
 
   @ssynchronized(_LOCK_ATTR)
     self._locks = weakref.WeakKeyDictionary()
 
   @ssynchronized(_LOCK_ATTR)

-  def RegisterLock(self, lock):
+  def RegisterLock(self, provider):

     """Registers a new lock.
 
     """Registers a new lock.
 

+    @param provider: Object with a callable method named C{GetLockInfo}, taking
+      a single C{set} containing the requested information items
+    @note: It would be nicer to only receive the function generating the
+      requested information but, as it turns out, weak references to bound
+      methods (e.g. C{self.GetLockInfo}) are tricky; there are several
+      workarounds, but none of the ones I found works properly in combination
+      with a standard C{WeakKeyDictionary}
+

     """
     """

-    logging.debug("Registering lock %s", lock.name)
-    assert lock not in self._locks, "Duplicate lock registration"
+    assert provider not in self._locks, "Duplicate registration"

 
     # There used to be a check for duplicate names here. As it turned out, when
     # a lock is re-created with the same name in a very short timeframe, the
 
     # There used to be a check for duplicate names here. As it turned out, when
     # a lock is re-created with the same name in a very short timeframe, the

@@ -1677,14 +1763,22 @@ class LockMonitor(object):
     # By keeping track of the order of incoming registrations, a stable sort
     # ordering can still be guaranteed.
 
     # By keeping track of the order of incoming registrations, a stable sort
     # ordering can still be guaranteed.
 

-    self._locks[lock] = self._counter.next()
+    self._locks[provider] = self._counter.next()

 
 

-  @ssynchronized(_LOCK_ATTR)

   def _GetLockInfo(self, requested):
   def _GetLockInfo(self, requested):

-    """Get information from all locks while the monitor lock is held.
+    """Get information from all locks.

 
     """
 
     """

-    return [(num, lock.GetInfo(requested)) for lock, num in self._locks.items()]
+    # Must hold lock while getting consistent list of tracked items
+    self._lock.acquire(shared=1)
+    try:
+      items = self._locks.items()
+    finally:
+      self._lock.release()
+
+    return [(info, idx, num)
+            for (provider, num) in items
+            for (idx, info) in enumerate(provider.GetLockInfo(requested))]

 
   def _Query(self, fields):
     """Queries information from all locks.
 
   def _Query(self, fields):
     """Queries information from all locks.

@@ -1701,7 +1795,7 @@ class LockMonitor(object):
                       key=_MonitorSortKey)
 
     # Extract lock information and build query data
                       key=_MonitorSortKey)
 
     # Extract lock information and build query data

-    return (qobj, query.LockQueryData(map(operator.itemgetter(1), lockinfo)))
+    return (qobj, query.LockQueryData(map(compat.fst, lockinfo)))

 
   def QueryLocks(self, fields):
     """Queries information from all locks.
 
   def QueryLocks(self, fields):
     """Queries information from all locks.