On Sat, 2012-04-28 at 17:54 +0800, Liu Yuan wrote:
> On 04/28/2012 05:49 PM, Shevek wrote:
>
> > On Sat, 2012-04-28 at 17:34 +0800, Liu Yuan wrote:
> >> On 04/28/2012 05:22 PM, Shevek wrote:
> >>
> >>>>> - if (join_finished)
> >>>>> + if (join_finished || is_master(&cevent->sender))
> >>> I believe this patch does NOT work:
> >>>
> >>> 1) is_master returns -1 for not-master, 0 means the given node is
> >>> master, so this is apparently a misuse of is_master.
> >>>
> >>> However, even worse:
> >>>
> >>> 2) If we never got a join response, then line 388:
> >>> 388 if (!cevent->blocked && cpg_node_equal(&cevent->sender,
> >>> &this_node)) {
> >>> never triggered, therefore we have never set join_finished, and
> >>> nr_cpg_nodes is always 0 (look for every place where it got set), so
> >>> is_master() is always 0.
> >>>
> >>> So, by inspection, this patch can never work, for both reasons.
> >>>
> >>
> >>
> >> Oh, yes. Thanks for pointing it out.
> >>
> >> But what if set set
> >>
> >> if (join_finished || (is_master(&cevent->sender >= 0)))
> >> done = __corosync_dispatch_one(cevent);
> >> else
> >> done = !cevent->blocked;
> >>
> >> Then, the master will be called for sure, and would give other nodes a
> >> join response.
> >
> > As I said before under (2), is_master() will always return 0, since the
> > only assignments to nr_cpg_nodes are within __corosync_dispatch_one()
> > (which has never yet been called) or when first_node == 1 (which never
> > happened).
> >
> > So this new patch is still invalid.
> >
>
>
> confchg event will be broadcast to all the nodes.
>
> for our case, if is_master() returns >=0, it means the very node *is*
> the master, then will call into __corosync_dispatch_one[1], where then
> it will call into send_message(response).
>
> so your assumption for (2) isn't valid.
Wrong. Read is_master():
243 static int is_master(struct cpg_node *node)
244 {
245 int i;
246 struct cpg_node *n = node;
247 if (!n)
248 n = &this_node;
249 if (nr_cpg_nodes == 0)
250 /* this node should be the first cpg node */
251 return 0;
^^^ This line is always hit because nr_cpg_nodes is always 0. Nobody set
it to anything other than 0.
252
253 for (i = 0; i < SD_MAX_NODES; i++) {
254 if (!cpg_nodes[i].gone)
255 break;
256 }
257
258 if (cpg_node_equal(&cpg_nodes[i], n))
259 return i;
260 return -1;
261 }
S.
> [1]
> if (join_finished || (is_master(&cevent->sender >= 0)))
> done = __corosync_dispatch_one(cevent);
>
> Thanks,
> Yuan
>
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