cman members are queried in response to a callback,
and members sometimes leave and rejoin between queries
(e.g. when they leave and rejoin before corosync
detects they left.)

This means that simply checking if a node is a member
in consecutive queries sometimes misses events.  We
need to compare the incarnation numbers of members
from consecutive queries to avoid this.

bz 663397

Signed-off-by: David Teigland <teigl...@redhat.com>
---
 fence/fenced/member_cman.c |   36 ++++++++++++++++++++++++++++++++++++
 1 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/fence/fenced/member_cman.c b/fence/fenced/member_cman.c
index 0919b8e..ee879be 100644
--- a/fence/fenced/member_cman.c
+++ b/fence/fenced/member_cman.c
@@ -33,6 +33,17 @@ void kick_node_from_cluster(int nodeid)
        }
 }
 
+static cman_node_t *get_node(cman_node_t *node_list, int count, int nodeid)
+{
+       int i;
+
+       for (i = 0; i < count; i++) {
+               if (node_list[i].cn_nodeid == nodeid)
+                       return &node_list[i];
+       }
+       return NULL;
+}
+
 static int is_member(cman_node_t *node_list, int count, int nodeid)
 {
        int i;
@@ -149,6 +160,7 @@ int name_to_nodeid(char *name)
 static void update_cluster(void)
 {
        cman_cluster_t info;
+       cman_node_t *old;
        int quorate = cluster_quorate;
        int removed = 0, added = 0;
        int i, rv;
@@ -197,6 +209,30 @@ static void update_cluster(void)
 
                        node_history_cluster_add(cman_nodes[i].cn_nodeid);
                        added++;
+               } else {
+                       /* look for any nodes that were members of both
+                        * old and new but have a new incarnation number
+                        * from old to new, indicating they left and rejoined
+                        * in between */
+
+                       old = get_node(old_nodes, old_node_count, 
cman_nodes[i].cn_nodeid);
+
+                       if (!old)
+                               continue;
+                       if (cman_nodes[i].cn_incarnation == old->cn_incarnation)
+                               continue;
+
+                       log_debug("cluster node %d removed and added seq %u "
+                                 "old %u new %u",
+                                 cman_nodes[i].cn_nodeid, cluster_ringid_seq,
+                                 old->cn_incarnation,
+                                 cman_nodes[i].cn_incarnation);
+
+                       node_history_cluster_remove(cman_nodes[i].cn_nodeid);
+                       removed++;
+
+                       node_history_cluster_add(cman_nodes[i].cn_nodeid);
+                       added++;
                }
        }
 
-- 
1.7.6

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