bugfix: backport an upstream patch to fix '/run/libvirt/qemu/dbus' racing bug

There are races condiction to make '/run/libvirt/qemu/dbus' directory in
virDirCreateNoFork() while concurrent start VMs, and get "failed to create
directory '/run/libvirt/qemu/dbus': File exists" error message. pre-create the
dbus directory in qemuStateInitialize.

Signed-off-by: Bihong Yu <yubihong@huawei.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>

libvirt-qemu-pre-create-the-dbus-directory-in-qemuStateIniti.patch

@@ -0,0 +1,92 @@
+From 3ee423c363b69588e82e522ad1634193284c09a7 Mon Sep 17 00:00:00 2001
+From: Bihong Yu <yubihong@huawei.com>
+Date: Tue, 14 Jul 2020 15:44:05 +0800
+Subject: [PATCH] qemu: pre-create the dbus directory in qemuStateInitialize
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+There are races condiction to make '/run/libvirt/qemu/dbus' directory in
+virDirCreateNoFork() while concurrent start VMs, and get "failed to create
+directory '/run/libvirt/qemu/dbus': File exists" error message. pre-create the
+dbus directory in qemuStateInitialize.
+
+Signed-off-by: Bihong Yu <yubihong@huawei.com>
+Reviewed-by: Ján Tomko <jtomko@redhat.com>
+Signed-off-by: Ján Tomko <jtomko@redhat.com>
+---
+ src/qemu/qemu_dbus.c    | 10 ----------
+ src/qemu/qemu_dbus.h    |  2 --
+ src/qemu/qemu_driver.c  |  7 +++++++
+ src/qemu/qemu_process.c |  3 ---
+ 4 files changed, 7 insertions(+), 15 deletions(-)
+
+diff --git a/src/qemu/qemu_dbus.c b/src/qemu/qemu_dbus.c
+index 51f6c94e3e..81042876fe 100644
+--- a/src/qemu/qemu_dbus.c
++++ b/src/qemu/qemu_dbus.c
+@@ -33,16 +33,6 @@
+ VIR_LOG_INIT("qemu.dbus");
+ 
+ 
+-int
+-qemuDBusPrepareHost(virQEMUDriverPtr driver)
+-{
+-    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+-
+-    return virDirCreate(cfg->dbusStateDir, 0770, cfg->user, cfg->group,
+-                        VIR_DIR_CREATE_ALLOW_EXIST);
+-}
+-
+-
+ static char *
+ qemuDBusCreatePidFilename(virQEMUDriverConfigPtr cfg,
+                           const char *shortName)
+diff --git a/src/qemu/qemu_dbus.h b/src/qemu/qemu_dbus.h
+index 474eb1058b..3c2145a223 100644
+--- a/src/qemu/qemu_dbus.h
++++ b/src/qemu/qemu_dbus.h
+@@ -21,8 +21,6 @@
+ #include "qemu_conf.h"
+ #include "qemu_domain.h"
+ 
+-int qemuDBusPrepareHost(virQEMUDriverPtr driver);
+-
+ char *qemuDBusGetAddress(virQEMUDriverPtr driver,
+                          virDomainObjPtr vm);
+ 
+diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
+index 8e81c30a93..53980d4d78 100644
+--- a/src/qemu/qemu_driver.c
++++ b/src/qemu/qemu_driver.c
+@@ -743,6 +743,13 @@ qemuStateInitialize(bool privileged,
+         goto error;
+     }
+ 
++    if (virDirCreate(cfg->dbusStateDir, 0770, cfg->user, cfg->group,
++                     VIR_DIR_CREATE_ALLOW_EXIST) < 0) {
++        virReportSystemError(errno, _("Failed to create dbus state dir %s"),
++                             cfg->dbusStateDir);
++        goto error;
++    }
++
+     if ((qemu_driver->lockFD =
+          virPidFileAcquire(cfg->stateDir, "driver", false, getpid())) < 0)
+         goto error;
+diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
+index e8b15ee3ca..1006f41614 100644
+--- a/src/qemu/qemu_process.c
++++ b/src/qemu/qemu_process.c
+@@ -6466,9 +6466,6 @@ qemuProcessPrepareHost(virQEMUDriverPtr driver,
+     qemuDomainObjPrivatePtr priv = vm->privateData;
+     g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+ 
+-    if (qemuDBusPrepareHost(driver) < 0)
+-        return -1;
+-
+     if (qemuPrepareNVRAM(cfg, vm) < 0)
+         return -1;
+ 
+-- 
+2.25.0.windows.1
+

libvirt.spec

@@ -99,7 +99,7 @@
 Summary: Library providing a simple virtualization API
 Name: libvirt
 Version: 6.2.0
-Release: 10
+Release: 11
 License: LGPLv2+
 URL: https://libvirt.org/
 
@@ -149,6 +149,7 @@ Patch0038: libvirt-conf-Increase-cpuset-length-limit-for-CPU-pinning.patch
 Patch0039: libvirt-virQEMUDriverConfigNew-Add-slash-to-cfg-defaultTLSx5.patch
 Patch0040: libvirt-qemuDomainSetNumaParamsLive-set-nodeset-for-root-cgr.patch
 Patch0041: libvirt-qemu-do-not-add-model-when-actual-iface-type-is-host.patch
+Patch0042: libvirt-qemu-pre-create-the-dbus-directory-in-qemuStateIniti.patch
 
 Requires: libvirt-daemon = %{version}-%{release}
 Requires: libvirt-daemon-config-network = %{version}-%{release}
@@ -1881,6 +1882,8 @@ exit 0
 
 
 %changelog
+* Tue Sep 22 2020 Zeyu Jin <jinzeyu@huawei.com> - 6.2.0-11
+- bugfix: backport an upstream patch to fix '/run/libvirt/qemu/dbus' racing bug.
 * Tue Sep 22 2020 Jin Yan <jinyan12@huawei.com> - 6.2.0-10
 - bugfix: cherry-pick some bugfix patches from opensource community
 * Wed Aug 5 2020 AlexChen <alex.chen@huawei.com> - 6.2.0-9