[pve-devel] [RFC qemu-server] API/create: move locking inside worker

[Thomas Lamprecht]

Move the locking inside worker, so that the process doing the actual
work (create or restore) holds the lock, and can call functions which
do locking without deadlocking.

This mirrors the behaviour we use for containers, and allows to add
an 'autostart' parameter which starts the VM after successful
creation. vm_start needs the lock and as not the worker but it's
parents held it, it couldn't know that it was actually save to
continue...

Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
---

I discussed this with Fabian a few months ago and have something in
mind that this shouldn't be that easy, but I cannot remember what
exactly that reason was, so RFC. :)

 PVE/API2/Qemu.pm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 0f27d29..8695e94 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -560,7 +560,7 @@ __PACKAGE__->register_method({
 	    # ensure no old replication state are exists
 	    PVE::ReplicationState::delete_guest_states($vmid);
 
-	    return $rpcenv->fork_worker('qmrestore', $vmid, $authuser, $realcmd);
+	    return PVE::QemuConfig->lock_config_full($vmid, 1, $realcmd);
 	};
 
 	my $createfn = sub {
@@ -607,10 +607,13 @@ __PACKAGE__->register_method({
 		PVE::AccessControl::add_vm_to_pool($vmid, $pool) if $pool;
 	    };
 
-	    return $rpcenv->fork_worker('qmcreate', $vmid, $authuser, $realcmd);
+	    return PVE::QemuConfig->lock_config_full($vmid, 1, $realcmd);
 	};
 
-	return PVE::QemuConfig->lock_config_full($vmid, 1, $archive ? $restorefn : $createfn);
+	my $worker_name = $archive ? 'qmrestore' : 'qmcreate';
+	my $code = $archive ? $restorefn : $createfn;
+
+	return $rpcenv->fork_worker($worker_name, $vmid, $authuser, $code);
     }});
 
 __PACKAGE__->register_method({
-- 
2.14.2