[PATCH storage 2/3] fix #8286: vdisk free: do not hold inherited locks in cleanup worker

["Michael Köppl" <m.koeppl@proxmox.com>]

vdisk_free() forks the cleanup worker of a volume (e.g. for wiping LVs
on LVM storages with saferemove), while the caller often still holds the
guest config lock. The worker inherits the locked handle and keeps the
lock held until the cleanup is done. For example, after destroying a VM
through the API, re-creating a VM with the same VMID fails with a lock
timeout until the wipe has finished.

The cleanup workers in the LVM plugin only operate on volumes that are
not referenced anymore. The plugin's implementation takes the lock on
its own where needed, so close the inherited lock handles when the
worker starts. This applies to the cleanup worker of any plugin, which
must not rely on the cleanup worker holding the caller's lock.

Signed-off-by: Michael Köppl <m.koeppl@proxmox.com>
---

Notes:
    I'm not quite sure about this one. I understand that it breaks this
    behavior for existing external plugins, but I'm not sure it's something
    they should rely on in the first place. An alternative to this would be
    to put the cleanup call into the LVM plugin's cleanup worker
    specifically, which would also require every plugin to implement this
    in its cleanup worker. Could perhaps also be a sensible approach for
    now to have the call in the LVM plugin specifically and move it to
    vdisk_free for PVE 10. I mostly decided on this version for now because
    of Fabian's comment on the Bugzilla ticket.

 src/PVE/Storage.pm | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/PVE/Storage.pm b/src/PVE/Storage.pm
index d660cfc4..4cec7c31 100755
--- a/src/PVE/Storage.pm
+++ b/src/PVE/Storage.pm
@@ -1222,7 +1222,15 @@ sub vdisk_free {
     my $rpcenv = PVE::RPCEnvironment::get();
     my $authuser = $rpcenv->get_user();
 
-    $rpcenv->fork_worker('imgdel', undef, $authuser, $cleanup_worker);
+    $rpcenv->fork_worker(
+        'imgdel',
+        undef,
+        $authuser,
+        sub {
+            PVE::Tools::close_inherited_lock_handles();
+            $cleanup_worker->(@_);
+        },
+    );
 }
 
 sub vdisk_list {
-- 
2.47.3