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# Date Author Comment
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 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 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