From 3b53c47155e22bdde258630f5e7b88f7ee3806aa Mon Sep 17 00:00:00 2001
From: Fabian Ebner <f.ebner@proxmox.com>
Date: Thu, 27 Jan 2022 15:01:55 +0100
Subject: [PATCH] clone disk: don't modify drive parameter

While existing callers are not using the parameter after the call,
the modification is rather unexpected and could lead to bugs quickly.

Also avoid setting an undef value in the hash, but use delete instead.

Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
---
 PVE/QemuServer.pm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 4f531f2e..8aa19469 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -7642,8 +7642,8 @@ sub clone_disk {
 no_data_clone:
     my ($size) = eval { PVE::Storage::volume_size_info($storecfg, $newvolid, 10) };
 
-    my $disk = $drive;
-    $disk->{format} = undef;
+    my $disk = dclone($drive);
+    delete $disk->{format};
     $disk->{file} = $newvolid;
     $disk->{size} = $size if defined($size);