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

[Fabian Grünbichler]

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?

> +	{
> +	    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;