cluster: RHEL53 - cman: Fix a situation where cman could kill thewrong nodes

[Christine Caulfield <chrissie at fedoraproject dot org>]

Gitweb:        http://git.fedorahosted.org/git/cluster.git?p=cluster.git;a=commitdiff;h=114f3e4edb206505b21152f2fe62474b62938369
Commit:        114f3e4edb206505b21152f2fe62474b62938369
Parent:        f19cc83e347ccc639bd54635adeb2e77bbbf2e66
Author:        Christine Caulfield <ccaulfie@redhat.com>
AuthorDate:    Wed Jul 29 11:17:47 2009 +0100
Committer:     Christine Caulfield <ccaulfie@redhat.com>
CommitterDate: Wed Aug 19 13:26:25 2009 +0100

cman: Fix a situation where cman could kill the wrong nodes

hmm, how to describe this .... Hmmmm. OK lets try:

There were a couple of places in the cman code where the transition message
assumed that the node in question (either this node or the sending node) was
joining the cluster, rather than just sending it's current post-transition
state. This was wrong. It's a common problem we have with openais/corosync
in that it always merges clusters rather than joining from scratch so we
need to detect that in some way.

The code in ais.c has a flag called 'first_trans' which it sets when it first
encounters another node in the cluster. We should use this more often as it's
really helpful. So this is what we now do. The comments in the existing code
make it clear that it assumed the node was joining and not just part of an
existing transition, but the first_trans flag was not checked, so it was
fairly obvious what was going on.

So, now we check the first_trans flag in all places where the code assumes
that the node is joining a new cluster.

rhbz#518061

Signed-off-by: Christine Caulfield <ccaulfie@redhat.com>
---
 cman/daemon/commands.c |   16 +++++++++-------
 1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/cman/daemon/commands.c b/cman/daemon/commands.c
index 46ab3fd..aede063 100644
--- a/cman/daemon/commands.c
+++ b/cman/daemon/commands.c
@@ -80,6 +80,7 @@ static openais_timer_handle quorum_device_timer;
 static openais_timer_handle ccsd_timer;
 static unsigned int wanted_config_version;
 static int config_error;
+static int local_first_trans;
 
 static openais_timer_handle shutdown_timer;
 static struct connection *shutdown_con;
@@ -1541,6 +1542,7 @@ void send_transition_msg(int last_memb_count, int first_trans)
 	int len = sizeof(struct cl_transmsg);
 
 	we_are_a_cluster_member = 1;
+	local_first_trans = first_trans;
 
 	P_MEMB("sending TRANSITION message. cluster_name = %s\n", cluster_name);
 	msg->cmd = CLUSTER_MSG_TRANSITION;
@@ -1717,9 +1719,9 @@ static void do_process_transition(int nodeid, char *data, int len)
 		return; // PJC ???
 	}
 
-	/* If the remote node can see AISONLY nodes then we can't join as we don't
-	   know the full state */
-	if (msg->flags & NODE_FLAGS_SEESDISALLOWED && !have_disallowed()) {
+	/* If the remote node can see AISONLY nodes and we want to join,
+	   then we can't, as we don't know the full state */
+	if (local_first_trans && msg->flags & NODE_FLAGS_SEESDISALLOWED && !have_disallowed()) {
 		/* Must use syslog directly here or the message will never arrive */
 		syslog(LOG_CRIT, "CMAN: Joined a cluster with disallowed nodes. must die");
 		exit(2);
@@ -1779,10 +1781,10 @@ static void do_process_transition(int nodeid, char *data, int len)
 		add_ais_node(nodeid, incarnation, num_ais_nodes);
 	}
 
-	/* If the cluster already has some AISONLY nodes then we can't make
-	   sense of the membership. So the new node has to also be AISONLY
-	   until we are consistent again */
-	if (have_disallowed() && !node->us)
+	/* If the new node is joining and the existing cluster already has some AISONLY
+	   nodes then we can't make sense of the membership.
+	   So the new node has to also be AISONLY until we are consistent again */
+	if (msg->first_trans && !node->us && have_disallowed())
 		node->state = NODESTATE_AISONLY;
 
 	node->flags = msg->flags; /* This will clear the BEENDOWN flag of course */