[pve-devel] [PATCH container] fix: cloning a locked container creates an empty config

Daniel Tschlatscher d.tschlatscher at proxmox.com
Tue Jun 14 15:43:21 CEST 2022



On 6/14/22 14:51, Fabian Grünbichler wrote:
> On June 14, 2022 2:22 pm, Daniel Tschlatscher wrote:
>> When an attempt was made to clone a locked container the API would
>> correctly present the error 'CT is locked (disk)' but create the
>> config files for the new container anyway and then abort.
>>
>> The fix is to simply check whether the CT config is locked before
>> creating the configs for the new container.
> 
> is there a reason for not just moving it to the start of the eval block 
> to avoid the same problem being re-introduced in the future? any error 
> occuring inside the eval block will then trigger a cleanup..
> 

When an error occurs and the cleanup is triggered, the cleanup tries to
release the lock again.

Moving the set_lock function into the eval block would create a problem
here:
If the lock was created by another process (and if it is a 'disk' lock)
set_lock would emit an error and the lock would be incorrectly released
by this process, which did not originally acquire it.

>>
>> Signed-off-by: Daniel Tschlatscher <d.tschlatscher at proxmox.com>
>> ---
>>  src/PVE/API2/LXC.pm | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
>> index 64724cb..e1b4cd3 100644
>> --- a/src/PVE/API2/LXC.pm
>> +++ b/src/PVE/API2/LXC.pm
>> @@ -1461,9 +1461,6 @@ __PACKAGE__->register_method({
>>  	my $vollist = [];
>>  	my $running;
>>  
>> -	PVE::LXC::Config->create_and_lock_config($newid, 0);
>> -	PVE::Firewall::clone_vmfw_conf($vmid, $newid);
>> -
>>  	my $lock_and_reload = sub {
>>  	    my ($vmid, $code) = @_;
>>  	    return PVE::LXC::Config->lock_config($vmid, sub {
>> @@ -1477,6 +1474,9 @@ __PACKAGE__->register_method({
>>  
>>  	my $src_conf = PVE::LXC::Config->set_lock($vmid, 'disk');
>>  
>> +	PVE::LXC::Config->create_and_lock_config($newid, 0);
>> +	PVE::Firewall::clone_vmfw_conf($vmid, $newid);
>> +
>>  	$running = PVE::LXC::check_running($vmid) || 0;
>>  
>>  	my $full = extract_param($param, 'full');
>> -- 
>> 2.30.2
>>
>>
>>
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>>
>>
> 
> 
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