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Posted to dev@zookeeper.apache.org by andreareale <gi...@git.apache.org> on 2018/10/09 15:42:22 UTC

[GitHub] zookeeper pull request #662: ZOOKEEPER-3162

GitHub user andreareale opened a pull request:

    https://github.com/apache/zookeeper/pull/662

    ZOOKEEPER-3162

    This PR fixes a few issues with the C client lock-recipe, as documented in more detailed in [ZOOKEEPER-3162](https://issues.apache.org/jira/browse/ZOOKEEPER-3162) on JIRA.
    
    Details are also provided in the individual commits, but in short:
    - Fix a bug in the choice of the predecessor node while trying to acquire the lock
    - Fix a possible deadlock in zkr_lock_operation
    - Fix the return value of zkr_lock_lock to abide to the prescribed semantics.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/ibm-research-ireland/zookeeper ZOOKEEPER-3162

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/zookeeper/pull/662.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #662
    
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commit f5b0e09820fa0713d64119e4ba70fe0d07533a96
Author: Andrea Reale <re...@...>
Date:   2018-10-09T09:23:50Z

    Fix wrong include path for C recipes
    
    Signed-off-by: Andrea Reale <re...@ie.ibm.com>

commit d6e1953840f56c2c42948ff1958be779465e2bb9
Author: Andrea Reale <re...@...>
Date:   2018-08-03T16:35:56Z

    Bugfix on zookeeper-recipes-lock C implementation
    
    - Fixes ZOOKEEPER-2408,ZOOKEEPER-2038, and (partly) ZOOKEEPER-2878
    - Fixes child_floor by using strcmp_suffix instead of strcmp. This will
      do the correct lookups within the sorted waiters list. Without this
      the lock semantics are broken: e.g., assuming that session A < session
      B (alfanumerically), if a thread from session B holds the lock, and a
      thread from session A tries to acquire it it will find no predecessor
      in child_floor and get the lock as well.
    - Uses binary search to find child_floor (optimization)
    
    Signed-off-by: Andrea Reale <re...@ie.ibm.com>

commit e95da861ba0340949baa65b6f143d8a4e67aee6c
Author: Andrea Reale <re...@...>
Date:   2018-08-15T16:35:07Z

    Fixes deadlock in zoo_lock_operation
    
    zkr_lock_operation is always called by holding the mutex associated to
    the client lock. In some cases, zkr_lock_operaton may decide to give-up
    locking and call zkr_lock_unlock to release the lock. When this happens,
    it will try to acquire again the same phtread mutex, which will lead to
    a deadlock.
    
    This commit fixes the issue by calling a non-protected version of
    zkr_lock_unlock from within zkr_lock_operatino.
    
    Signed-off-by: Andrea Reale <re...@ie.ibm.com>

commit 51ac01ecd06aca9d368519ff925a3539ddef35b4
Author: Andrea Reale <re...@...>
Date:   2018-10-09T14:52:11Z

    Fix return semantics of zkr_lock_lock
    
    Returns 0 (on no-errors) from zkr_lock_lock. This matches the
    API documentation. Additionall, returning zkr_lock_isowner is also
    semantically wrong: a caller might be enqueued for lock acquision and
    still not the owner; in such a case the function should still return 0
    because that is the expected behavior.
    
    Signed-off-by: Andrea Reale <re...@ie.ibm.com>

----


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by andreareale <gi...@git.apache.org>.

Github user andreareale commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    retest this please


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by asfgit <gi...@git.apache.org>.

Github user asfgit commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    
    Refer to this link for build results (access rights to CI server needed): 
    https://builds.apache.org/job/PreCommit-ZOOKEEPER-github-pr-build/2397/



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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by nkalmar <gi...@git.apache.org>.

Github user nkalmar commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    Looks good, thanks @andreareale 
    The C test fail looks like it's the flaky one:
    *** Error in `./zktest-mt': free(): invalid pointer: 0x00002b913dcd5000 ***
    I think there's already a fix underway.
    
    This should also go into 3.5 as well (possibly to 3.4 especially the include path fix).


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by andreareale <gi...@git.apache.org>.

Github user andreareale commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    Hi @nkalmar, @tamaashu and thanks for the reviews. Any chance to see this merged any time soon?


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by nkalmar <gi...@git.apache.org>.

Github user nkalmar commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    retest this please


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by anmolnar <gi...@git.apache.org>.

Github user anmolnar commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    Committed to 3.5 and master branches. Thanks @andreareale !
    Please create separate pull request for branch-3.4


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[GitHub] zookeeper issue #662: ZOOKEEPER-3162. Broken lock semantics in C client lock...

Posted by andreareale <gi...@git.apache.org>.

Github user andreareale commented on the issue:

    https://github.com/apache/zookeeper/pull/662
  
    Thanks @nkalmar. There were some additional path issues in the recipes ant test targets. Updated the PR to fix them as well. Please, let me know if there is anything I can do to help with merging.


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