Re: [pve-devel] [PATCH qemu-server 2/2] backup: use dirty-bitmap for PBS only if supported by QEMU

[Stefan Reiter <s.reiter@proxmox.com>]

On 7/8/20 11:08 AM, Thomas Lamprecht wrote:
> On 08.07.20 10:42, Stefan Reiter wrote:
>> If 'query-proxmox-support' is not known to QEMU, assume that no other
>> features are supported either.
>>
>> Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
>> ---
>>
>> Does not require any version bumps, since it handles failure gracefully.
>>
>>   PVE/VZDump/QemuServer.pm | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/PVE/VZDump/QemuServer.pm b/PVE/VZDump/QemuServer.pm
>> index 567088c..3c2a334 100644
>> --- a/PVE/VZDump/QemuServer.pm
>> +++ b/PVE/VZDump/QemuServer.pm
>> @@ -443,6 +443,8 @@ sub archive_pbs {
>>   	    die "interrupted by signal\n";
>>   	};
>>   
>> +	my $qemu_support = eval { mon_cmd($vmid, "query-proxmox-support") } // {};
> 
> can we not fall back and instead use undef here to error out with a nice
> "does not support PBS at all" message?
>

If we want that, sure. Though I think it might be cleaner to also have a 
'pbs' feature as well, I don't like the approach of implicitly detecting 
support just because a QMP command exists.

I'll send a v2.

>> +
>>   	my $fs_frozen = $self->qga_fs_freeze($task, $vmid);
>>   
>>   	my $params = {
>> @@ -453,11 +455,13 @@ sub archive_pbs {
>>   	    password => $password,
>>   	    devlist => $devlist,
>>   	    'config-file' => $conffile,
>> -	    'use-dirty-bitmap' => JSON::true,
>>   	};
>>   	$params->{fingerprint} = $fingerprint if defined($fingerprint);
>>   	$params->{'firewall-file'} = $firewall if -e $firewall;
>>   
>> +	$params->{'use-dirty-bitmap'} = JSON::true
>> +	    if $qemu_support->{'pbs-dirty-bitmap'};
>> +
>>   	$params->{timeout} = 60; # give some time to connect to the backup server
>>   
>>   	my $res = eval { mon_cmd($vmid, "backup", %$params) };
>>
>