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# Date Author Comment
7f93570a 07/16/2010 04:56 pm Iustin Pop

Implement lock names for debugging purposes

This patch adds lock names to SharedLocks and LockSets, that can be used
later for displaying the actual locks being held/used in places where we
only have the lock, and not the entire context of the locking operation....

dbb11e8b 06/28/2010 02:04 pm Guido Trotter

ssynchronized: act on a class member

The ssynchronized decorator takes the lock to act on in input.
With this change we allow a string to be passed, and if so we assume the
function it protects is a class method, and we act on the member of the
class itself named as the string we got....

cdf158a8 06/11/2010 12:23 pm Guido Trotter

Remove locking._CountingCondition

This class is unused and untested. We must have forgot it around.

Signed-off-by: Guido Trotter <>
Reviewed-by: Michael Hanselmann <>

7f890059 06/10/2010 05:45 pm Guido Trotter

_BaseCondition: allow saving/restoring state

Signed-off-by: Guido Trotter <>
Reviewed-by: Michael Hanselmann <>

1a4e32d0 06/10/2010 05:45 pm Guido Trotter

SharedLock _acquire_restore and _release_save

If a shared lock is used inside a condition, we need to make sure that
it's reacquired in the same way as it was originally, after the wait.

Signed-off-by: Guido Trotter <>
Reviewed-by: Michael Hanselmann <>

cea881e5 04/21/2010 08:48 pm Michael Hanselmann

Add separate module for backported language functionality

utils.py, where they were before, is already huge.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

ef7b75b2 02/15/2010 07:03 pm Michael Hanselmann

Merge remote branch 'origin/stable-2.1' into devel-2.1

  • origin/stable-2.1:
    Fix bug introduced in commit 413b747
    Fix locking bug causing high CPU usage
    Fix confd procotol design description
    Implement instance rename QA tests
    Fix "gnt-instance rename" functionality...
b44b0141 02/10/2010 03:54 pm Michael Hanselmann

Fix bug introduced in commit 413b747

While commit 413b747 fixed the issue of poll(2) returning too
soon, it didn't work when the poll(2) call should've been
blocking. This is now fixed and verified.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

413b7472 02/10/2010 02:49 pm Michael Hanselmann

Fix locking bug causing high CPU usage

Iustin Pop noticed unusually high CPU usage with 2.1's master
daemon, even with very simple opcodes like OP_TEST_DELAY. As
it turns out, we inadvertently passed seconds as milliseconds
to a call to poll(2). Due to the way the loop around the call...

ec44d893 01/27/2010 12:19 pm Guido Trotter

locking: add/fix @type information

This patch missing @type information for all public methods, modifies
one to conform to the rest, and removes some information from @param
when it's been expressed in @type.

Signed-off-by: Guido Trotter <>...

154b9580 01/27/2010 11:17 am Balazs Lecz

Fix slots definitions

According to http://docs.python.org/reference/datamodel.html#slots

  • The action of a slots declaration is limited to the class where it
    is defined. As a result, subclasses will have a dict unless they
    also define slots (which must only contain names of any...
71e1863e 01/13/2010 03:02 pm Michael Hanselmann

locking: Fix race condition in LockSet

This patch fixes a race condition when acquiring all locks in
a LockSet instance. The list of lock names needs to be sorted
to guarantee a consistent locking order, but the names were not
sorted when acquiring all locks in the set....

9b154270 01/13/2010 03:02 pm Michael Hanselmann

locking: Append to list outside error handling block

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

56452af7 01/13/2010 03:02 pm Michael Hanselmann

locking: Don't fail in error handling if lock isn't owned

In case an exception was thrown while acquiring the lock, not necessarily all
owned locks are also really acquired. Before this change, an exception could be
masked by another exception thrown here. There is no good clean-up strategy...

7260cfbe 01/04/2010 11:15 am Iustin Pop

Add targeted pylint disables

This patch should have only:

- pylint disables
- docstring changes
- whitespace changes

Signed-off-by: Iustin Pop <>
Reviewed-by: Olivier Tharan <>

d984846d 12/28/2009 02:05 pm Iustin Pop

Merge branch 'devel-2.0' into devel-2.1

  • devel-2.0:
    Fix indentation in hv_kvm
    Implement BuildHooksEnv for NoHooksLU
    Clarifiy some more wide pylint disables
    Fix two bugs in seldom-used codepaths
    Update pylintrc
    Add targetted pylint disables
    Partial cherry-pick of 6c881c5 from the 2.1 branch...
fe267188 12/28/2009 12:43 pm Iustin Pop

Add targetted pylint disables

This patch adds targeted pylint disables, where it makes sense (either
due to limitations in pylint or due to historical usage), and also a few
blanket ones in rapi where all the names are… “different”.

Signed-off-by: Iustin Pop <>...

c70d2d9b 12/28/2009 12:43 pm Iustin Pop

Clarifiy some more wide pylint disables

This removes/updates some module-wide pylint disables.

Signed-off-by: Iustin Pop <>
Reviewed-by: Olivier Tharan <>

1f864b60 11/25/2009 04:30 pm Iustin Pop

Remove quotes from CommaJoin and convert to it

This patch removes the quotes from CommaJoin and converts most of the
callers (that I could find) to it. Since CommaJoin does str(i) for i in
param, we can remove these, thus simplifying slightly a few calls....

f4e673fb 10/15/2009 05:47 pm Michael Hanselmann

locking: Convert pipe condition to new timeout class

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

7e8841bd 10/15/2009 05:47 pm Michael Hanselmann

locking.LockSet: Move timeout calculation to separate class

This class can also be used by mcpu.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

b6b87034 10/15/2009 05:47 pm Michael Hanselmann

locking, mcpu: Ensure timeout is always >= 0.0

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

e4335b5b 10/13/2009 08:08 pm Michael Hanselmann

locking.LockSet: Improve assertions

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

76e2f08a 10/13/2009 08:08 pm Michael Hanselmann

locking: Factorize LockSet.acquire

By moving the main code of LockSet.acquire to its own function
we reduce the code complexity a bit and clarify the exception
handling.

This also fixes a case where a lock acquire timeout wasn't
handled correctly, leading to obscure error messages....

69b99987 10/12/2009 01:48 pm Michael Hanselmann

Code and docstring style fixes

Found using pylint and epydoc.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

5aab242c 10/12/2009 01:46 pm Michael Hanselmann

locking.LockSet: Implement acquire timeouts

The timeout passed to LockSet.acquire() is measured over all lock acquires. If
LockSet.acquire fails to acquire all requested locks within the specified
amount of time, all locks are released again and the acquire fails....

008b92fa 10/02/2009 03:04 pm Michael Hanselmann

More locking tests race conditions fixes

There were more race conditions. By adding a notify function to
SharedLock.acquire we can prevent them.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

34cb5617 10/01/2009 07:47 pm Guido Trotter

SingleActionPipeCondition =~ s/Action/Notify/

With this patch we simplify usage on the SingleActionCondition (which
wasn't a condition at all) by making it a real condition. This way we
can just wait() on it, or notifyAll() as we would on a normal one. The...

2419060d 10/01/2009 07:45 pm Guido Trotter

Abstract "base" condition code in a separate class

Each condition has an underlying lock, the acquire and release methods,
and a few helper methods to check that it's called in the proper way.

Abstract them to a separate class so we can have more than one without...

a66bd91b 10/01/2009 07:35 pm Michael Hanselmann

locking.SharedLock: Fix bug in delete function

SharedLock.__acquire_unlocked uses keyword parameters. Just passing
the timeout would set the “shared” parameter.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

5e0a6daf 10/01/2009 07:17 pm Michael Hanselmann

Rename LockSet.acquire parameter “blocking” to “timeout”

Also remove the “blocking” parameter from LockSet.remove and
GanetiLockManager.remove. There's no point in implementing timeouts on removal
unless we need them.

Signed-off-by: Michael Hanselmann <>...

c6997f21 09/30/2009 06:35 pm Michael Hanselmann

Change SharedLock to new pipe(2)-based condition

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

48dabc6a 09/30/2009 06:34 pm Michael Hanselmann

Add _PipeCondition class

_PipeCondition is a condition implemented using pipe(2) and poll(2).
It allows the implementation of timeouts without using a busy-wait loop
with time.sleep.

Unlike Python's built-in threading.Condition class and to save file
descriptors and an internal queue, it can only be used to notify...

d76167a5 09/30/2009 06:34 pm Michael Hanselmann

Add _SingleActionPipeCondition class

This class will be used as a basic block for pipe(2)-based
conditions. Upon initialization it creates a pipe and can be
notified once (hence the “single action” in the name). A
callable helper class is used to wait for notifications....

84e344d4 09/30/2009 06:33 pm Michael Hanselmann

SharedLock: implement timeouts

This patch greatly simplifies the SharedLock code and implements
timeouts for the acquire() and delete() functions. A wrapper around
Python's threading.Condition class must be used to ensure thread
safety when check whether there are any waiters left....

9216a9f7 09/14/2009 02:21 pm Michael Hanselmann

locking: Acquire SharedLock in shared mode in separate function

This is for some more symetry with
SharedLock.__exclusive_acquire.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

ea205dbc 09/14/2009 02:16 pm Michael Hanselmann

locking: Add level name dict

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Olivier Tharan <>

470ce2ee 09/11/2009 06:29 pm Michael Hanselmann

locking: Don't swallow exceptions

This is an indentation bug.

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Guido Trotter <>

5bbd3f7f 07/07/2009 03:51 pm Michael Hanselmann

Fix some typos

Signed-off-by: Michael Hanselmann <>
Reviewed-by: Iustin Pop <>

2a21bc88 01/29/2009 05:08 pm Iustin Pop

locking.LockSet: don't modify input arguments

Currently LockSet.acquire() sorts in place it's input argument if it's a
list. This is not good, since callers might depend on a specific
ordering of the input data, and this is a 'hidden' modification.

We fix it by simply using a sorted copy, instead of sorting in place....

f12eadb3 01/29/2009 05:08 pm Iustin Pop

Re-wrap some lines to keep them under 80 chars

This non-code change rewraps some lines in locking.py to keep them under
80 chars.

Reviewed-by: ultrotter

c41eea6e 12/11/2008 07:13 pm Iustin Pop

Fix epydoc format warnings

This patch should fix all outstanding epydoc parsing errors; as such, we
switch epydoc into verbose mode so that any new errors will be visible.

Reviewed-by: imsnah

d2aff862 09/11/2008 12:44 pm Guido Trotter

LockSet: forbid add() on a partially owned set

This patch bans add() on a half-acquired set. This behavior was
previously possible, but created a deadlock if someone tried to acquire
the set-lock in the meantime, and thus is now forbidden. The
testAddRemove unit test is fixed for this new behavior, and includes a...

ab62526c 09/11/2008 12:43 pm Guido Trotter

Fix typo in a locking.py comment

Reviewed-by: imsnah

d4f4b3e7 09/11/2008 12:43 pm Guido Trotter

Add GanetiLockManager.is_owned function

This is a public version of the private function we already had.
We don't just change the previous version because it had lots of users
in the library itself and in the testing code.

Reviewed-by: imsnah

d4803c24 09/11/2008 12:43 pm Guido Trotter

Fix LockSet._names() to work with the set-lock

If the set-lock is acquired, currently, the _names function will fail on
a double acquire of a non-recursive lock. This patch fixes the behavior,
and some lines of code added to the testAcquireSetLock test check that...

e310b019 09/05/2008 02:00 pm Guido Trotter

Add locking.ALL_SET constant and use it

Rather than specifying None in needed_locks every time, with a nice
comment saying to read what we mean rather than what we write, and that
None actually means All, in our magic world, we'll hide this secret
under the ALL_SET constant in the locking module, which has value, you...

34ca3914 08/18/2008 03:50 pm Guido Trotter

LockSet: allow lists with duplicate values

If a list with a duplicate value is passed to a lockset what the code
now does is to try to acquire the lock twice, generating a
double-acquire exception in the SharedLock code. This is definitely an
issue. In order to solve it we can either forbit double values in a list...

04e1bfaf 07/23/2008 05:23 pm Guido Trotter

Invert nodes/instances locking order

An implementation mistake from the original design caused nodes to be
locked before instances, rather than after. This patch inverts the level
numbering, changing also the relevant unittests and the recursive
locking function starting point....

08a6c581 07/08/2008 11:41 am Guido Trotter

Locking: remove LEVEL_CONFIG lockset

Since the ConfigWriter now handles its own locking it's not necessary to
have a specific level for the config in the Locking Manager anymore.
This patch thus removes it, and all the unittest calls that used it, or
depended on it being present....

42a999d1 07/08/2008 11:40 am Guido Trotter

Locking: add ssynchronized decorator

This patch creates a new decorator function ssynchronized in the locking
library, which takes as input a SharedLock, and synchronizes access to
the decorated functions using it. The usual SharedLock semantics apply,
so it's possible to call more than one synchronized function at the same...

94285814 04/15/2008 02:54 pm Guido Trotter

SharedLock: restrict assertion condition

When we release a shared lock if there are no exclusive waiter then the number
of shared waiters must be exactly equal to the ones scheduled to pass.

Reviewed-by: iustinp

c5cc3403 04/02/2008 12:53 pm Guido Trotter

Locking: fix one indentation error (codestyle)

Reviewed-by: imsnah

4e07ec8c 04/02/2008 12:52 pm Guido Trotter

Locking: fix superlong lines (codestyle)

Reviewed-by: imsnah

21a6c826 03/18/2008 12:09 pm Guido Trotter

Locking: remove an empty space at End Of Line

Reviewed-by: imsnah

4d686df8 03/18/2008 12:08 pm Guido Trotter

Increase SharedLock fairness

Previously if a shared thread was notified, together with the rest, and was not
fast enough in waking up and acquiring the lock, another one could release it,
decide there were no more sharers, and let an exclusive one in instead. With...

b2dabfd6 03/04/2008 07:12 pm Guido Trotter

LockSet: handle empty case

A LockSet is mostly useful when it has some locks in it. On the other hand
there are cases in which it must function even when empty. For example if a
cluster has no instances in it there's no reason why locking all of them
shouldn't work anyway. This patch adds test code for that situation and...

ea3f80bf 03/04/2008 07:12 pm Guido Trotter

LockSet: collapse two try/except into one

Reviewed-by: imsnah

9a39f854 03/04/2008 07:11 pm Guido Trotter

SharedLock: remove wrong assertion in code

r644 contained some cleanup code for LockSet. Among other things it removed a
syntax error that allowed an assertion that previously wan't really checked to
trigger. It turns out that even though the spirit of that assertion was correct...

cdb08f44 03/04/2008 04:46 pm Michael Hanselmann

Codestyle updates for locking code

Reviewed-by: ultrotter

3b7ed473 03/04/2008 03:18 pm Guido Trotter

LockSet: make acquire() able to get the whole set

This new functionality makes it possible to acquire a whole set, by passing
"None" to the acquire() function as the list of elements. This will avoid new
additions to the set, and then acquire all the current elements. The list of...

806e20fd 03/04/2008 03:18 pm Guido Trotter

LockSet: encapsulate acquire() in try-except

This patch adds a try/except area around most of the acquire() code (everything
after the intial condition checks). Since the except: clause contains just a
'raise' nothing really changes except the indentation of the code....

0cf257c5 03/04/2008 03:17 pm Guido Trotter

Make LockSet.__names() return a list, not a set

Previously the private version of the __names function returned directly a set.
We'll keep this in the public interface but change the private version to a
list in order to be able to sort() its result and then loop on it, even though...

3f404fc5 03/04/2008 03:17 pm Guido Trotter

LockSet: improve remove() api

Lockset's remove() function used to return a list of locks we failed to remove.
Rather than doing this we'll return a list of removed locks, so it's more
similar to how acquire() behaves. This patch also fixes the relevant unit tests....

0cc00929 03/04/2008 03:17 pm Guido Trotter

LockSet: make acquire() return the set of names

In a LockSet acquire() returned True on success. This code changes that to
return a set containing the names of the elements acquired. This is still a
true value if we acquired any lock but is slightly more useful (because if...

8b68f394 03/04/2008 03:16 pm Guido Trotter

LockSet: invert try/for nesting in acquire()

This patch changes nothing to the functionality of a LockSet. Rather than
trying to do the whole for loop we try each of its steps. This opens the way to
handle differently a single failure.

Reviewed-by: imsnah

7ee7c0c7 03/04/2008 12:09 pm Guido Trotter

Initial GanetiLockManager implementation

Includes some locking-related constants and explanations on how the
LockManager should be used, the class itself and its test cases.

The class includes:
- a basic constructor
- functions to acquire and release lists of locks at the same level...

e6c200d6 02/28/2008 08:53 pm Guido Trotter

LockSet: make acquire() fail faster on wrong locks

This patch makes acquire() first look up all the locks in the dict and then try
to acquire them later. The advantage is that if a lockname is already wrong
since the beginning we won't need to first queue and acquire other locks to...

aaae9bc0 02/28/2008 05:06 pm Guido Trotter

LockSet implementation and unit tests

A LockSet represents locking for a set of resources of the same type. A thread
can acquire multiple resources at the same time, and release some or all of
them, but cannot acquire more resources incrementally at different times...

a95fd5d7 02/19/2008 03:50 pm Guido Trotter

Add the delete() operation to SharedLock

This new operation lets a lock be cleanly deleted. The lock will be exclusively
held before deletion, and after it pending and future acquires will raise an
exception. Other SharedLock operations are modify to deal with delete() and to...

d6646186 02/18/2008 06:58 pm Guido Trotter

Fix a couple of SharedLock docstrings

Use the actual class name rather than a spaced version of it.

Reviewed-by: iustinp

162c1c1f 02/08/2008 01:23 pm Guido Trotter

Shared Lock implementation and unit tests.

Adding a locking.py file for the ganeti locking library. Its first component is
the implementation of a non-recursive blocking shared lock complete with a
testing library.

Reviewed-by: imsnah, iustinp