[Cluster-devel] [PATCH 3/3] gfs_controld: full check for member changes

[David Teigland]

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 <teigland at redhat.com>
---
 group/gfs_controld/member_cman.c |   51 +++++++++++++++++++++++++++++++++++---
 1 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/group/gfs_controld/member_cman.c b/group/gfs_controld/member_cman.c
index 277a11e..7f354b1 100644
--- a/group/gfs_controld/member_cman.c
+++ b/group/gfs_controld/member_cman.c
@@ -9,6 +9,7 @@ static cman_node_t      old_nodes[MAX_NODES];
 static int              old_node_count;
 static cman_node_t      cman_nodes[MAX_NODES];
 static int              cman_node_count;
+static uint32_t         cluster_ringid_seq;
 
 void kick_node_from_cluster(int nodeid)
 {
@@ -22,6 +23,17 @@ 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;
@@ -45,8 +57,18 @@ static int is_cluster_member(int nodeid)
 
 static void statechange(void)
 {
+	cman_cluster_t info;
+	cman_node_t *old;
 	int i, rv;
 
+	rv = cman_get_cluster(ch, &info);
+	if (rv < 0) {
+		log_error("cman_get_cluster error %d %d", rv, errno);
+		/* keep going, this is just informational */
+		memset(&info, 0, sizeof(info));
+	}
+	cluster_ringid_seq = info.ci_generation;
+
 	old_node_count = cman_node_count;
 	memcpy(&old_nodes, &cman_nodes, sizeof(old_nodes));
 
@@ -70,8 +92,8 @@ static void statechange(void)
 		if (old_nodes[i].cn_member &&
 		    !is_cluster_member(old_nodes[i].cn_nodeid)) {
 
-			log_debug("cluster node %d removed",
-				  old_nodes[i].cn_nodeid);
+			log_debug("cluster node %d removed seq %u",
+				  old_nodes[i].cn_nodeid, cluster_ringid_seq);
 
 			node_history_cluster_remove(old_nodes[i].cn_nodeid);
 		}
@@ -81,10 +103,31 @@ static void statechange(void)
 		if (cman_nodes[i].cn_member &&
 		    !is_old_member(cman_nodes[i].cn_nodeid)) {
 
-			log_debug("cluster node %d added",
-				  cman_nodes[i].cn_nodeid);
+			log_debug("cluster node %d added seq %u",
+				  cman_nodes[i].cn_nodeid, cluster_ringid_seq);
 
 			node_history_cluster_add(cman_nodes[i].cn_nodeid);
+		} 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);
+			node_history_cluster_add(cman_nodes[i].cn_nodeid);
 		}
 	}
 }
-- 
1.7.6