[pve-devel] [PATCH qemu-server 2/2] api: template: invert lock and fork

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

like for other API calls, repeat the cheap checks done for early abort
before forking and without locks after forking and obtaining the lock,
and only hold the flock in the forked worker instead of across the fork.

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
not sure whether we want to switch to the "progress bar -> task viewer"
thing in the GUI for this endpoint? it's usually instant, except when
the storage is very slow/overloaded/..

 PVE/API2/Qemu.pm | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 0a23525..a8fbd9d 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -4353,8 +4353,7 @@ __PACKAGE__->register_method({
 
 	my $disk = extract_param($param, 'disk');
 
-	my $updatefn =  sub {
-
+	my $load_and_check = sub {
 	    my $conf = PVE::QemuConfig->load_config($vmid);
 
 	    PVE::QemuConfig->check_lock($conf);
@@ -4368,17 +4367,23 @@ __PACKAGE__->register_method({
 	    die "you can't convert a VM to template if VM is running\n"
 		if PVE::QemuServer::check_running($vmid);
 
-	    my $realcmd = sub {
-		PVE::QemuServer::template_create($vmid, $conf, $disk);
-	    };
+	    return $conf;
+	};
 
-	    $conf->{template} = 1;
-	    PVE::QemuConfig->write_config($vmid, $conf);
+	$load_and_check->();
 
-	    return $rpcenv->fork_worker('qmtemplate', $vmid, $authuser, $realcmd);
+	my $realcmd = sub {
+	    PVE::QemuConfig->lock_config($vmid, sub {
+		my $conf = $load_and_check->();
+
+		$conf->{template} = 1;
+		PVE::QemuConfig->write_config($vmid, $conf);
+
+		PVE::QemuServer::template_create($vmid, $conf, $disk);
+	    });
 	};
 
-	return PVE::QemuConfig->lock_config($vmid, $updatefn);
+	return $rpcenv->fork_worker('qmtemplate', $vmid, $authuser, $realcmd);
     }});
 
 __PACKAGE__->register_method({
-- 
2.30.2