[PATCH qemu-server 3/7] fix #8071: volume snapshot delete: use current drive information to fix SAVC handling

[Fiona Ebner <f.ebner@proxmox.com>]

When removing a volume chain snapshot, the blockdev properties are
re-generated in blockdev_{commit,replace,stream}() to operate upon.
This must happen with the current drive information, not the one from
the time the snapshot was taken.

A similar bug was present before volume chain snapshots existed, and
fixed by commit c6058683 ("fix #2258: select correct device when
removing drive snapshot via QEMU"). This is where the handling for
$attached_deviceid comes from. With snapshot-as-volume-chain, this
needs to be extended to the full drive information, not just the
device ID.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 src/PVE/QemuConfig.pm | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/PVE/QemuConfig.pm b/src/PVE/QemuConfig.pm
index 3dd69ce8..39e88366 100644
--- a/src/PVE/QemuConfig.pm
+++ b/src/PVE/QemuConfig.pm
@@ -441,13 +441,19 @@ sub __snapshot_delete_vol_snapshot {
     my $running = PVE::QemuServer::Helpers::vm_running_locally($vmid);
     my $attached_deviceid;
 
+    # Need to operate on the currently attached device if the VM is running for QMP handling to
+    # work correctly. For blockdev generation, it's also important that the same drive information
+    # as currently attached is used, because otherwise node names and other settings might differ.
     if ($running) {
         my $conf = $class->load_config($vmid);
         $class->foreach_volume(
             $conf,
             sub {
-                my ($ds, $drive) = @_;
-                $attached_deviceid = "drive-$ds" if $drive->{file} eq $volid;
+                my ($ds, $current_drive) = @_;
+                if ($current_drive->{file} eq $volid) {
+                    $attached_deviceid = "drive-$ds";
+                    $drive = $current_drive;
+                }
             },
         );
     }
-- 
2.47.3