[Engine-devel] LockManager maybe not be really taking locks in your flows...

Allon Mureinik amureini at redhat.com
Mon Aug 12 07:12:40 UTC 2013



----- Original Message -----
> From: "Allon Mureinik" <amureini at redhat.com>
> To: "Roy Golan" <rgolan at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>
> Sent: Monday, August 12, 2013 9:59:17 AM
> Subject: Re: [Engine-devel] LockManager maybe not be really taking locks in your flows...
> 
> 
> 
> ----- Original Message -----
> > From: "Roy Golan" <rgolan at redhat.com>
> > To: "Yair Zaslavsky" <yzaslavs at redhat.com>
> > Cc: "engine-devel" <engine-devel at ovirt.org>
> > Sent: Sunday, August 11, 2013 5:16:47 PM
> > Subject: Re: [Engine-devel] LockManager maybe not be really taking locks in
> > your flows...
> > 
> > On Sun 11 Aug 2013 05:14:04 PM IDT, Roy Golan wrote:
> > > On Sun 11 Aug 2013 05:03:05 PM IDT, Yair Zaslavsky wrote:
> > >> Hi all,
> > >> Thanks to Alon Bar Lev's efforts for preventing to concurrent host
> > >> installation for the same host entity + Roy Golan's check of the
> > >> code, we saw that for commands that override
> > >>
> > >> getExclusiveLocks() or getSharedLocks() the locking mechanism does
> > >> not work (lock is not being acquired) if there is no annotation of
> > >> @LockIdNameAttribute on the class.
> > >> A bug was filed for removing this annotation (leftover from some
> > >> historical code ) , but until it is fixed - bare in mind you need to
> > >> add this annotation in current commands you are working on
> > >> in order to utilize the mechanism.
> > >> See RemoveVmCommand (has the annotation) vs AddDiskCommand (which
> > >> doesn't have the annotation)
> > >>
> > >>
> > >> Cheers,
> > >> Yair
> > >> _______________________________________________
> > >> Engine-devel mailing list
> > >> Engine-devel at ovirt.org
> > >> http://lists.ovirt.org/mailman/listinfo/engine-devel
> > >
> > > just to make it clear, the storage commands are calling explicitly
> > > aquireLockInternal in the canDoAction. since there is no contract (no
> > > interface) we are open to mistakes and misuse. this should be rectified.
> > >
> > more info from the bug:
> > see the list of commands that overrrides getExcelusiveLocks but *don't*
> > have the @LockIdNameAttribute annotation:
> > 
> > bll/src/main/java/org/ovirt/engine/core/bll/AddDiskCommand.java
> Manually calls acquireLockInternal() - disgusting, but works (on my todo list
> for some future version, don't worry).
> 
> > bll/src/main/java/org/ovirt/engine/core/bll/MoveOrCopyDiskCommand.java
> Same.
> 
> > bll/src/main/java/org/ovirt/engine/core/bll/AddVdsCommand.java
> > bll/src/main/java/org/ovirt/engine/core/bll/UpdateVmTemplateCommand.java

> > bll/src/main/java/org/ovirt/engine/core/bll/ExportRepoImageCommand.java
Fixed: http://gerrit.ovirt.org/#/c/17946/

> > 
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > 
> _______________________________________________
> Engine-devel mailing list
> Engine-devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/engine-devel
> 



More information about the Engine-devel mailing list