From 29b57a2f15b8993935947e12692693a01efeaefb Mon Sep 17 00:00:00 2001
From: Laine Stump <laine@laine.org>
Date: Tue, 25 Apr 2017 12:20:30 -0400
Subject: [PATCH] qemu: don't kill qemu process on restart if networkNotify
 fails

Nothing that could happen during networkNotifyActualDevice() could
justify unceremoniously killing the qemu process, but that's what we
were doing.

In particular, new code added in commit 85bcc022 (first appearred in
libvirt-3.2.0) attempts to reattach tap devices to their assigned
bridge devices when libvirtd restarts (to make it easier to recover
from a restart of a libvirt network). But if the network has been
stopped and *not* restarted, the bridge device won't exist and
networkNotifyActualDevice() will fail.

This patch changes networkNotifyActualDevice() and
qemuProcessNotifyNets() to return void, so that qemuProcessReconnect()
will soldier on regardless of what happens (any errors will still be
logged though).

Partially resolves: https://bugzilla.redhat.com/1442700

(cherry picked from commit cb182eb11d3a99adb06e188989899dcd488c43fc)
---
 src/network/bridge_driver.c | 10 ++++------
 src/network/bridge_driver.h |  7 +++----
 src/qemu/qemu_process.c     |  9 +++------
 3 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index ef982363b4..cb91a2c902 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -4656,9 +4656,9 @@ networkAllocateActualDevice(virDomainDefPtr dom,
  * order, or re-attach the interface's tap device to the network's
  * bridge.
  *
- * Returns 0 on success, -1 on failure.
+ * No return value (but does log any failures)
  */
-int
+void
 networkNotifyActualDevice(virDomainDefPtr dom,
                           virDomainNetDefPtr iface)
 {
@@ -4668,11 +4668,10 @@ networkNotifyActualDevice(virDomainDefPtr dom,
     virNetworkDefPtr netdef;
     virNetworkForwardIfDefPtr dev = NULL;
     size_t i;
-    int ret = -1;
     char *master = NULL;
 
     if (iface->type != VIR_DOMAIN_NET_TYPE_NETWORK)
-        return 0;
+        return;
 
     network = virNetworkObjFindByName(driver->networks, iface->data.network.name);
     if (!network) {
@@ -4848,11 +4847,10 @@ networkNotifyActualDevice(virDomainDefPtr dom,
     }
     networkLogAllocation(netdef, actualType, dev, iface, true);
 
-    ret = 0;
  cleanup:
     virNetworkObjEndAPI(&network);
     VIR_FREE(master);
-    return ret;
+    return;
 
  error:
     goto cleanup;
diff --git a/src/network/bridge_driver.h b/src/network/bridge_driver.h
index c696f0301f..aaedd67a19 100644
--- a/src/network/bridge_driver.h
+++ b/src/network/bridge_driver.h
@@ -37,8 +37,8 @@ int networkRegister(void);
 int networkAllocateActualDevice(virDomainDefPtr dom,
                                 virDomainNetDefPtr iface)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
-int networkNotifyActualDevice(virDomainDefPtr dom,
-                              virDomainNetDefPtr iface)
+void networkNotifyActualDevice(virDomainDefPtr dom,
+                               virDomainNetDefPtr iface)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 int networkReleaseActualDevice(virDomainDefPtr dom,
                                virDomainNetDefPtr iface)
@@ -72,11 +72,10 @@ int networkBandwidthUpdate(virDomainNetDefPtr iface,
 #  define networkDnsmasqConfContents(network, pidfile, configstr, \
                     dctx, caps) 0
 
-static inline int
+static inline void
 networkNotifyActualDevice(virDomainDefPtr dom ATTRIBUTE_UNUSED,
                           virDomainNetDefPtr iface ATTRIBUTE_UNUSED)
 {
-    return 0;
 }
 
 static inline int
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 961afd70a9..26a668d27e 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2825,7 +2825,7 @@ int qemuProcessStopCPUs(virQEMUDriverPtr driver,
 
 
 
-static int
+static void
 qemuProcessNotifyNets(virDomainDefPtr def)
 {
     size_t i;
@@ -2840,10 +2840,8 @@ qemuProcessNotifyNets(virDomainDefPtr def)
         if (virDomainNetGetActualType(net) == VIR_DOMAIN_NET_TYPE_DIRECT)
            ignore_value(virNetDevMacVLanReserveName(net->ifname, false));
 
-        if (networkNotifyActualDevice(def, net) < 0)
-            return -1;
+        networkNotifyActualDevice(def, net);
     }
-    return 0;
 }
 
 static int
@@ -3478,8 +3476,7 @@ qemuProcessReconnect(void *opaque)
     if (qemuSecurityReserveLabel(driver->securityManager, obj->def, obj->pid) < 0)
         goto error;
 
-    if (qemuProcessNotifyNets(obj->def) < 0)
-        goto error;
+    qemuProcessNotifyNets(obj->def);
 
     if (qemuProcessFiltersInstantiate(obj->def))
         goto error;