vm_resume: correctly honor $nocheck

for both vm_mon_cmd calls. under certain circumstances, the following
sequence of events can otherwise fail when live-migrating under load:

S...source node
T...target node

0: migration is complete, handover from S to T starts
1: S: logically move VM config file from S to T via rename()
2: S: rename returns, config file is (visibly) moved on S
3: S: trigger resume on T via mtunnel
4a: T: call vm_resume while config file move is not yet visible on T
4b: T: call vm_resume while config file move is already visible on T

4a instead of 4b means vm_mon_cmd will die in check_running unless
vm_mon_cmd_nocheck is used.

under heavy pmxcfs load and a slow cluster/corosync network, there can
be a few seconds of delay between 1 and 2, with a subsequent race ending in 4a
instead of 4b.

this issue was reported to occur on bulk migrations.

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index c342addc7e263976386438fada774b63f0abd6f9..1a22fb475b680166d5315cedb37791909e1f2015 100644 (file)
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -5766,8 +5766,8 @@ sub vm_resume {
     my ($vmid, $skiplock, $nocheck) = @_;
 
     PVE::QemuConfig->lock_config($vmid, sub {
-
-       my $res = vm_mon_cmd($vmid, 'query-status');
+       my $vm_mon_cmd = $nocheck ? \&vm_mon_cmd_nocheck : \&vm_mon_cmd;
+       my $res = $vm_mon_cmd->($vmid, 'query-status');
        my $resume_cmd = 'cont';
 
        if ($res->{status} && $res->{status} eq 'suspended') {
@@ -5780,12 +5780,9 @@ sub vm_resume {
 
            PVE::QemuConfig->check_lock($conf)
                if !($skiplock || PVE::QemuConfig->has_lock($conf, 'backup'));
-
-           vm_mon_cmd($vmid, $resume_cmd);
-
-       } else {
-           vm_mon_cmd_nocheck($vmid, $resume_cmd);
        }
+
+       $vm_mon_cmd->($vmid, $resume_cmd);
     });
 }