/**
* Check whether we're seen as coordinator by all the nodes in our clique.
* NOTE: This function assumes that we see ourself as coord.
*
* \return true if the whole clique agrees that we are coord, false otherwise
*/
static bool
clique_sees_self_as_coord(void)
{
exa_nodeid_t node_id;
for (node_id = 0; node_id < self->view.num_seen; node_id++)
if (exa_nodeset_contains(&self->view.clique, node_id))
{
sup_node_t *node = sup_cluster_node(&cluster, node_id);
EXA_ASSERT(node);
if (!self_sees(node))
return false;
if (!exa_nodeset_equals(&node->view.clique, &self->view.clique))
return false;
if (node->view.coord != self->view.coord)
return false;
}
__trace("clique_sees_self_as_coord -> YES");
return true;
}
/**
* Check equality of two views.
*
* Two views are equal if both their nodes seen and
* their coordinators are equal.
*
* \param[in] v1 View
* \param[in] v2 View
*
* \return true if views are equal, false otherwise
*/
bool
sup_view_equals(const sup_view_t *v1, const sup_view_t *v2)
{
EXA_ASSERT(v1 && v2);
return (v1->coord == v2->coord
&& exa_nodeset_equals(&v1->nodes_seen, &v2->nodes_seen));
}
/**
* Called in state ACCEPT to process a ping.
*
* \param[in] ping Ping to process
*/
static void
state_accept_process_ping(const sup_ping_t *ping)
{
switch (ping->view.state)
{
case SUP_STATE_UNKNOWN:
/* Not possible */
break;
case SUP_STATE_CHANGE:
/* Ignore: the event that triggered the sender's state change will
* eventually be seen by us, and our view will change too
*/
break;
case SUP_STATE_ACCEPT:
if (self_is_coord())
{
/* If the sender sees ourself as its coordinator and has accepted
* our proposed clique, check if we have reached the point where all
* nodes have accepted.
*
* If so, commit the clique. This will eventually trigger the commit
* on all other nodes.
*/
if (ping->view.coord == self->id
&& ping->view.accepted == self->view.accepted)
{
if (clique_has_accepted(self->view.accepted))
{
__trace(":):) ALL IN CLIQUE HAVE ACCEPTED VIEW WITH GEN %u",
self->view.accepted);
commit_clique();
}
}
}
break;
case SUP_STATE_COMMIT:
if (!self_is_coord())
{
/* If the sender views the same clique as us and its committed
* generation is equal to our accepted generation, commit.
*/
if (exa_nodeset_equals(&ping->view.clique, &accepted_clique)
&& ping->view.committed == self->view.accepted
&& ping->view.committed > self->view.committed)
{
__trace("saw commit %u from %u and i accepted %u => i commit %u",
ping->view.committed, ping->sender, self->view.accepted,
self->view.accepted);
commit_clique();
}
}
break;
}
}
/**
* Before sending a ping.
*/
static void
sup_pre_ping(void)
{
update_last_seen();
#ifdef USE_YAOURT
if (yaourt_event_wait(EXAMSG_CSUPD_ID, "sup_pre_ping") != 0)
self_view_changed = true;
#endif
if (self_view_changed || other_view_changed)
{
exa_nodeset_t new_clique;
bool clique_changed;
exa_nodeid_t coord;
__trace("RECALCULATING CLIQUE");
sup_clique_compute(&cluster, &new_clique);
clique_changed = !exa_nodeset_equals(&new_clique, &self->view.clique);
if (clique_changed)
{
exa_nodeset_copy(&self->view.clique, &new_clique);
coord = exa_nodeset_first(&self->view.clique);
if (coord != self->view.coord)
{
__trace("new coord: %u", coord);
self->view.coord = coord;
}
}
#ifdef DEBUG
{
char clique_str[EXA_MAX_NODES_NUMBER + 1];
exa_nodeset_to_bin(&self->view.clique, clique_str);
__trace("Clique: %s %s", clique_str, clique_changed ? "CHANGED" : "");
}
#endif
}
if (self_view_changed || other_view_changed)
{
__trace("*** SUP_MSHIP_CHANGE ***");
set_state(SUP_STATE_CHANGE);
}
#ifdef WITH_TRACE
dump_view(0);
#endif
}
/**
* Check whether all nodes in our clique have accepted the clique
* (aka membership) whose generation is given.
*
* \param[in] gen Membership generation
*
* \return true if all have accepted, false otherwise
*/
static bool
clique_has_accepted(sup_gen_t gen)
{
exa_nodeid_t node_id;
for (node_id = 0; node_id < self->view.num_seen; node_id++)
if (exa_nodeset_contains(&self->view.clique, node_id))
{
sup_node_t *node = sup_cluster_node(&cluster, node_id);
EXA_ASSERT(node);
if (!self_sees(node))
return false;
if (!exa_nodeset_equals(&node->view.clique, &self->view.clique))
return false;
if (node->view.accepted != gen)
return false;
}
return true;
}
/**
* Called in state CHANGE to process a ping.
*
* \param[in] ping Ping to process
*/
static void
state_change_process_ping(const sup_ping_t *ping)
{
switch (ping->view.state)
{
case SUP_STATE_UNKNOWN:
/* Not possible */
break;
case SUP_STATE_CHANGE:
if (self_is_coord())
{
__trace("i'm coord");
/* Go to state ACCEPT if all the nodes in our clique see us as
* their coordinator. This will initiate the agreement phase.
*/
if (clique_sees_self_as_coord())
{
__trace("+++ EVERYONE IN MY CLIQUE SEES ME AS COORD");
accept_clique(next_gen());
__trace("\t=> new state=%s, accepted=%u",
sup_state_name(self->view.state),
self->view.accepted);
}
}
break;
case SUP_STATE_ACCEPT:
if (!self_is_coord())
{
/* Go to state ACCEPT if the sender is our coordinator, views the
* same clique as us and its accepted clique generation is higher
* than ours.
*/
if (ping->sender == self->view.coord
&& exa_nodeset_equals(&ping->view.clique, &self->view.clique)
&& ping->view.accepted > self_highest_gen())
{
__trace("coord ok, view ok, accepted ok => i accept");
accept_clique(ping->view.accepted);
}
}
break;
case SUP_STATE_COMMIT:
if (!self_is_coord())
{
/* Commit the membership if we accepted it */
if (exa_nodeset_equals(&ping->view.clique, &accepted_clique)
&& ping->view.committed == self->view.accepted
&& ping->view.committed > self->view.committed)
{
__trace("saw commit %u from %u and i accepted %u => i commit %u",
ping->view.committed, ping->sender, self->view.accepted,
self->view.accepted);
commit_clique();
}
}
break;
}
}
