[pve-devel] [PATCH ha-manager v4 3/4] allow LRM lock stealing for fenced nodes

[Thomas Lamprecht]

We are only allowed to recover (=steal) a service when we have its
LRMs lock, as this guarantees us that even if said LRM comes up
again during the steal operation the LRM cannot start the services
when the service config still belongs to it for a short time.

This is important, else we have a possible race for the resource
which can result in a service started on the old (restarted) node
and the node where the service was recovered too, which is really
bad!

Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
---

_No_ changes here from v3.

 src/PVE/HA/Env.pm      |  4 ++--
 src/PVE/HA/Env/PVE2.pm |  4 ++--
 src/PVE/HA/Sim/Env.pm  | 16 ++++++++++------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/PVE/HA/Env.pm b/src/PVE/HA/Env.pm
index c7537b1..ff867c3 100644
--- a/src/PVE/HA/Env.pm
+++ b/src/PVE/HA/Env.pm
@@ -159,9 +159,9 @@ sub get_ha_agent_lock {
 # this should only get called if the nodes LRM gracefully shuts down with
 # all services already cleanly stopped!
 sub release_ha_agent_lock {
-    my ($self) = @_;
+    my ($self, $node) = @_;
 
-    return $self->{plug}->release_ha_agent_lock();
+    return $self->{plug}->release_ha_agent_lock($node);
 }
 
 # return true when cluster is quorate
diff --git a/src/PVE/HA/Env/PVE2.pm b/src/PVE/HA/Env/PVE2.pm
index 37823ee..79fe522 100644
--- a/src/PVE/HA/Env/PVE2.pm
+++ b/src/PVE/HA/Env/PVE2.pm
@@ -318,9 +318,9 @@ sub get_ha_agent_lock {
 # this should only get called if the nodes LRM gracefully shuts down with
 # all services already cleanly stopped!
 sub release_ha_agent_lock {
-    my ($self) = @_;
+    my ($self, $node) = @_;
 
-    my $node = $self->nodename();
+    $node = $node || $self->nodename();
 
     return rmdir("$lockdir/ha_agent_${node}_lock");
 }
diff --git a/src/PVE/HA/Sim/Env.pm b/src/PVE/HA/Sim/Env.pm
index 3715eff..678dcee 100644
--- a/src/PVE/HA/Sim/Env.pm
+++ b/src/PVE/HA/Sim/Env.pm
@@ -75,13 +75,17 @@ sub sim_get_lock {
 	    if (my $d = $data->{$lock_name}) {
 		my $tdiff = $ctime - $d->{time};
 
+		my $manager_node = $data->{'ha_manager_lock'}->{node} || '';
+
+		$res = 0;
 		if ($tdiff > $self->{lock_timeout}) {
 		    $res = 1;
-		} elsif (($tdiff <= $self->{lock_timeout}) && ($d->{node} eq $nodename)) {
-		    delete $data->{$lock_name};
-		    $res = 1;
 		} else {
-		    $res = 0;
+		    # if we aren't manager we may unlock only *our* lock
+		    if ($d->{node} eq $nodename || $manager_node eq $nodename) {
+			delete $data->{$lock_name};
+			$res = 1;
+		    }
 		}
 	    }
 
@@ -277,9 +281,9 @@ sub get_ha_agent_lock {
 # this should only get called if the nodes LRM gracefully shuts down with
 # all services already cleanly stopped!
 sub release_ha_agent_lock {
-    my ($self) = @_;
+    my ($self, $node) = @_;
 
-    my $node = $self->nodename();
+    $node = $node || $self->nodename();
 
     my $lock = $self->get_ha_agent_lock_name($node);
     return $self->sim_get_lock($lock, 1);
-- 
2.1.4