[libvirt] [PATCH] qemu: hotplug: Ignore cgroup errors when hot-unplugging vcpus

[Peter Krempa]

When the vcpu is successfully removed libvirt would remove the cgroup.
In cases when removal of the cgroup fails libvirt would report an error.

This does not make much sense, since the vcpu was removed and we can't
really do anything with the cgroup. This patch silences the errors from
cgroup removal.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1462092
---
 src/qemu/qemu_hotplug.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 7592049ea..4913e18e6 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -5322,6 +5322,7 @@ qemuDomainRemoveVcpu(virQEMUDriverPtr driver,
     qemuDomainVcpuPrivatePtr vcpupriv = QEMU_DOMAIN_VCPU_PRIVATE(vcpuinfo);
     int oldvcpus = virDomainDefGetVcpus(vm->def);
     unsigned int nvcpus = vcpupriv->vcpus;
+    virErrorPtr save_error = NULL;
     size_t i;

     if (qemuDomainRefreshVcpuInfo(driver, vm, QEMU_ASYNC_JOB_NONE, false) < 0)
@@ -5346,11 +5347,12 @@ qemuDomainRemoveVcpu(virQEMUDriverPtr driver,

     virDomainAuditVcpu(vm, oldvcpus, oldvcpus - nvcpus, "update", true);

-    for (i = vcpu; i < vcpu + nvcpus; i++) {
-        vcpuinfo = virDomainDefGetVcpu(vm->def, i);
-        if (virCgroupDelThread(priv->cgroup, VIR_CGROUP_THREAD_VCPU, i) < 0)
-            return -1;
-    }
+    virErrorPreserveLast(&save_error);
+
+    for (i = vcpu; i < vcpu + nvcpus; i++)
+        ignore_value(virCgroupDelThread(priv->cgroup, VIR_CGROUP_THREAD_VCPU, i));
+
+    virErrorRestore(&save_error);

     return 0;
 }
-- 
2.14.1