[Pacemaker] Suggestion to improve movement of booth

[Jiaju Zhang]

On Tue, 2013-01-15 at 11:28 +0900, yusuke iida wrote:
> Hi, Jiaju
> 
> 2013/1/11 Jiaju Zhang <jjzhang at suse.de>:
> > Hi Yusuke,
> >
> > Sorry for the late reply;)
> >
> > On Mon, 2013-01-07 at 13:50 +0900, yusuke iida wrote:
> >> Hi, Jiaju
> >>
> >> When the proposal was conflict, I want to keep on the site of the
> >> original lease.
> >> I do not want to generate a revoke when maintained.
> >>
> >>
> >> I made a patch according to a thought of "5.2 Master lease" described
> >> in the next article.
> >> It means that it prevents you from accepting new suggestion until a
> >> time limit of lease expires.
> >
> > Exactly.
> >
> >>
> >> http://www.read.seas.harvard.edu/~kohler/class/08w-dsi/chandra07paxos.pdf
> >>
> >> Is there anything wrong with this idea?
> >
> > This idea is totally right. But we have already implemented it. When the
> > master exists and is still in its lease, if some other one wants to be
> > the master and sent the "prepare" message, the acceptor will told him
> > "oh, we have already had a master" by setting "hdr->leased = 1" in his
> > respond message, actually this is a rejection, then the one trying to be
> > master won't succeed.
> I understand these specifications.
> However, by the present specification, when returning "hdr->leased =
> 1", "highest_promised" is updated by ballot of new "prepare".
> When "highest_promised" is updated, reaccession of lease is carried
> out in original masters.
> Since revoke is performed at this time, the node which the resource
> was start(ing) is STONITH(ed) by loss-policy=fence.
> As for this, the stop of temporary service happens.
> To avoid this, I've implemented the change not to do to re-acquire the lease.

Understood, this is an important fix. However, it seems that there is an
easier way to fix this, just change the return value of "lease_promise",
that is to say, return -1 when having leased. 

I'm inclined to do so because the new function "lease_is_leased"
basically did the same thing with "lease_promise", but "lease_promise"
returned a wrong value currently. What do you think?;)

BTW, don't forget to add your Signed-off-by line and check the patch
with checkpatch.pl, this will make booth to use the same coding style;)

Thanks,
Jiaju