[pve-devel] [PATCH qemu-server v2 1/1] fix #5619: honor link_down setting when hot-plugging nic

[Stefan Hanreich]

When detaching and attaching the network device on update, the
link_down setting is not considered and the network device always gets
attached to the guest - even if link_down is set.

Fixes: 3f14f206 ("nic online bridge/vlan change: link disconnect/reconnect")
Signed-off-by: Stefan Hanreich <s.hanreich at proxmox.com>
Reviewed-by: Fiona Ebner <f.ebner at proxmox.com>
---
Changes from v1 -> v2:
* Fixed trailers in commit message
* Re-added comment describing the reason for setting link_down on
  changed bridge/tag

Thanks @Fiona for your suggestions!

 PVE/QemuServer.pm | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 88c274d..39d729c 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -5339,20 +5339,18 @@ sub vmconfig_update_net {
 		    PVE::Network::tap_plug($iface, $newnet->{bridge}, $newnet->{tag}, $newnet->{firewall}, $newnet->{trunks}, $newnet->{rate});
 		}
 
-		#set link_up in guest if bridge or vlan change to notify guest (dhcp renew for example)
-		if (safe_string_ne($oldnet->{bridge}, $newnet->{bridge}) ||
-		    safe_num_ne($oldnet->{tag}, $newnet->{tag})
-		) {
-		    qemu_set_link_status($vmid, $opt, 1);
-		}
-
 	    } elsif (safe_num_ne($oldnet->{rate}, $newnet->{rate})) {
 		# Rate can be applied on its own but any change above needs to
 		# include the rate in tap_plug since OVS resets everything.
 		PVE::Network::tap_rate_limit($iface, $newnet->{rate});
 	    }
 
-	    if (safe_string_ne($oldnet->{link_down}, $newnet->{link_down})) {
+	    # set link_down on changed bridge/tag as well, because we detach the
+	    # network device in the section above if the bridge or tag changed
+	    if (safe_string_ne($oldnet->{link_down}, $newnet->{link_down})
+		|| safe_string_ne($oldnet->{bridge}, $newnet->{bridge})
+		|| safe_num_ne($oldnet->{tag}, $newnet->{tag})
+	    ) {
 		qemu_set_link_status($vmid, $opt, !$newnet->{link_down});
 	    }
 
-- 
2.39.2