Re: [pve-devel] [PATCH qemu-server v2 1/1] fix 1734: clone VM: if deactivation fails demote error to warning

[Friedrich Weber <f.weber@proxmox.com>]

Tested-by: Friedrich Weber <f.weber@proxmox.com>

Can confirm the patch fixes the issue of parallel qmclones failing
occasionally due to a LVM deactivation error, and the extra \n in the
task log from v1 is gone.

One tiny comment inline:

On 06/03/2024 15:08, Hannes Duerr wrote:
> When a template with disks on LVM is cloned to another node, the volumes
> are first activated, then cloned and deactivated again after cloning.
> 
> However, if clones of this template are now created in parallel to other
> nodes, it can happen that one of the tasks can no longer deactivate the
> logical volume because it is still in use.  The reason for this is that
> we use a shared lock.
> Since the failed deactivation does not necessarily have consequences, we
> downgrade the error to a warning, which means that the clone tasks will
> continue to be completed successfully.
> 
> Signed-off-by: Hannes Duerr <h.duerr@proxmox.com>
> ---
> changes since v1:
> - fix nits and spelling
> 
>  PVE/API2/Qemu.pm | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
> index 69c5896..1ff5abe 100644
> --- a/PVE/API2/Qemu.pm
> +++ b/PVE/API2/Qemu.pm
> @@ -48,6 +48,7 @@ use PVE::DataCenterConfig;
>  use PVE::SSHInfo;
>  use PVE::Replication;
>  use PVE::StorageTunnel;
> +use PVE::RESTEnvironment qw(log_warn);
>  
>  BEGIN {
>      if (!$ENV{PVE_GENERATING_DOCS}) {
> @@ -3820,7 +3821,11 @@ __PACKAGE__->register_method({
>  
>  		if ($target) {
>  		    # always deactivate volumes - avoid lvm LVs to be active on several nodes
> -		    PVE::Storage::deactivate_volumes($storecfg, $vollist, $snapname) if !$running;
> +		    eval {
> +			PVE::Storage::deactivate_volumes($storecfg, $vollist, $snapname) if !$running;
> +		    };
> +		    log_warn($@) if ($@);

I suppose the parentheses in the post-if condition `if ($@)` are not
strictly necessary, but since ` ... if ($@);` does appear a couple of
times in our existing code, so probably not a problem.

> +
>  		    PVE::Storage::deactivate_volumes($storecfg, $newvollist);
>  
>  		    my $newconffile = PVE::QemuConfig->config_file($newid, $target);