[pve-devel] [PATCH qemu-server] vzdump: fix log output for disks with iothread

[Stefan Reiter]

On 2/27/20 11:48 AM, Fabian Grünbichler wrote:
> On February 26, 2020 11:53 am, Aaron Lauterer wrote:
>> If IO-Thread is activated and a new enough Qemu version installed the
>> program still ran into the elsif clause and never in the else clause.
>> Thus the "include disk ..." log output was missing for these disks.
>>
>> Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
>> ---
>>   PVE/VZDump/QemuServer.pm | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/PVE/VZDump/QemuServer.pm b/PVE/VZDump/QemuServer.pm
>> index 7695ad6..e36a259 100644
>> --- a/PVE/VZDump/QemuServer.pm
>> +++ b/PVE/VZDump/QemuServer.pm
>> @@ -79,11 +79,12 @@ sub prepare {
>>   	if (defined($drive->{backup}) && !$drive->{backup}) {
>>   	    $self->loginfo("exclude disk '$ds' '$volid' (backup=no)");
>>   	    return;
>> -	} elsif ($self->{vm_was_running} && $drive->{iothread}) {
>> -	    if (!PVE::QemuServer::Machine::runs_at_least_qemu_version($vmid, 4, 0, 1)) {
>> -		die "disk '$ds' '$volid' (iothread=on) can't use backup feature with running QEMU " .
>> +	} elsif ($self->{vm_was_running}
>> +		 && $drive->{iothread}
>> +		 && !PVE::QemuServer::Machine::runs_at_least_qemu_version($vmid, 4, 0, 1))
> not new, I know, but:
> 
> two of those three are not related to the drive. one of those two is
> actually a qmp call. instead of having a condition spanning three lines,
> we could refactor it like so:
> 
> my $iothread_allowed = -1; // to avoid repeated QMP calls
> 
> foreach_drive(..) {
> 
> my $iothread = $self->{vm_was_running} && $drive->{iothread}; // do we even care?
> if ($iothread && $iothread_allowed == -1) {
>      $iothread_allowed = PVE::QemuServer::Machine::runs_at_least_qemu_version(...); // cache on first use
> }
> 
> if ( ... ) {
> 
> } elsif ($iothread && !$iothread_allowed) { // simple condition ;)
>    die ...
> }
> 
> alternatively, the die could also move into the else branch, assuming we
> don't have efidisks with iothreads?
> 
> also, isn't this actually wrong? in stop mode, we'd get the new qemu
> version when it counts, even if the VM is running the old version right
> now?
> 

Doesn't a "stop" mode backup imply the VM being shut down and restarted 
before backup? I.e. the backup always will run on the currently 
installed QEMU version?

If that's the case, this is correct, since we only care about which QEMU 
version we send the QMP command to.

>> +	{
>> +	    die "disk '$ds' '$volid' (iothread=on) can't use backup feature with running QEMU " .
>>   		    "version < 4.0.1! Either set backup=no for this drive or upgrade QEMU and restart VM\n";
>> -	    }
>>   	} elsif ($ds =~ m/^efidisk/ && (!defined($conf->{bios}) || $conf->{bios} ne 'ovmf')) {
>>   	    $self->loginfo("excluding '$ds' (efidisks can only be backed up when BIOS is set to 'ovmf')");
>>   	    return;
> 
> 
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