[PATCH qemu-server 3/9] partially fix #7299: migrate: fix regression with guest IO limits applying to NBD export

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

Related to commit "partially fix #7299: fix regression with guest IO
limits applying to mirror job", but taking care of the NBD export on
the target side. Since the switch to -blockdev with version 10.0,
write limits intended for the guest would apply to NBD exports as
well. This is because the top throttle node was exported. Export the
node below instead to avoid the issue.

For the test, change to using the version of query-block from
the MigrationTest::Shared module to make it work.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 src/PVE/QemuServer.pm            | 13 ++++++++++++-
 src/test/MigrationTest/QmMock.pm |  7 -------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 9aec7f9c..6b03e170 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -5929,7 +5929,18 @@ sub vm_start_nolock {
             my $drivestr = $nbd->{$opt}->{drivestr};
             my $volid = $nbd->{$opt}->{volid};
 
-            my $block_node = $block_info->{$opt}->{inserted}->{'node-name'};
+            my $top = $block_info->{$opt}->{inserted};
+            die "no block node found for drive '$opt'\n" if !$top;
+            my $block_node = $top->{'node-name'};
+            my $machine_type = PVE::QemuServer::Machine::get_current_qemu_machine($vmid);
+            if (PVE::QemuServer::Machine::is_machine_version_at_least($machine_type, 10, 0)) {
+                # Since the switch to -blockdev with machine version 10, the top node is a throttle
+                # node. Use the node below it to avoid the guest limits applying to the NBD export.
+                die "top node for drive '$opt' is not a throttle node" if $top->{drv} ne 'throttle';
+                my $children = { map { $_->{child} => $_ } $top->{children}->@* };
+                $block_node = $children->{file}->{'node-name'}
+                    or die "drive '$opt': throttle node without file child node name\n";
+            }
 
             mon_cmd(
                 $vmid,
diff --git a/src/test/MigrationTest/QmMock.pm b/src/test/MigrationTest/QmMock.pm
index 8f8899dc..aa5fac4f 100644
--- a/src/test/MigrationTest/QmMock.pm
+++ b/src/test/MigrationTest/QmMock.pm
@@ -50,8 +50,6 @@ my sub mocked_mon_cmd {
         return;
     } elsif ($command eq 'block-export-add') {
         return;
-    } elsif ($command eq 'query-block') {
-        return [];
     } elsif ($command eq 'qom-set') {
         return;
     } elsif ($command eq 'query-version') {
@@ -70,11 +68,6 @@ $inotify_module->mock(
     },
 );
 
-my $qemu_server_blockdev_module = Test::MockModule->new("PVE::QemuServer::Blockdev");
-$qemu_server_blockdev_module->mock(
-    mon_cmd => \&mocked_mon_cmd,
-);
-
 my $qemu_server_helpers_module = Test::MockModule->new("PVE::QemuServer::Helpers");
 $qemu_server_helpers_module->mock(
     vm_running_locally => sub {
-- 
2.47.3