[libvirt] [PATCH] qemu_driver: add virCgroupMounted
When wen mount any cgroup without "-o devices", we will fail to start vms:
# virsh start vm1
error: Failed to start domain vm1
error: Unable to deny all devices for vm1: No such file or directory
When wen mount any cgroup without "-o cpu", we will fail to get schedinfo:
# virsh schedinfo vm1
Scheduler : posix
error: unable to get cpu shares tunable: No such file or directory
We should only use the cgroup controllers which are mounted on host.
So I add virCgroupMounted() for qemuCgroupControllerActive()
Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com>
---
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 3b127d6..5885ad8 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -61,6 +61,7 @@ virConfWriteMem;
# cgroup.h
virCgroupForDomain;
virCgroupForDriver;
+virCgroupMounted;
virCgroupRemove;
virCgroupFree;
virCgroupAddTask;
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 16f34f7..f09d029 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -724,6 +724,8 @@ static int qemuCgroupControllerActive(struct qemud_driver *driver,
{
if (driver->cgroup == NULL)
return 0;
+ if (!virCgroupMounted(driver->cgroup, controller))
+ return 0;
if (driver->cgroupControllers & (1 << controller))
return 1;
return 0;
diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index 7e887dc..8fac389 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -71,6 +71,17 @@ void virCgroupFree(virCgroupPtr *group)
VIR_FREE(*group);
}
+/**
+ * virCgroupMounted: query whether a cgroup subsystem is mounted or not
+ *
+ * @cgroup: The group structure to be queried
+ * @controller: cgroup subsystem id
+ */
+bool virCgroupMounted(virCgroupPtr cgroup, int controller)
+{
+ return !!cgroup->controllers[controller].mountPoint;
+}
+
#if defined HAVE_MNTENT_H && defined HAVE_GETMNTENT_R
/*
* Process /proc/mounts figuring out what controllers are
diff --git a/src/util/cgroup.h b/src/util/cgroup.h
index b8f2d08..9e1c61f 100644
--- a/src/util/cgroup.h
+++ b/src/util/cgroup.h
@@ -83,5 +83,6 @@ int virCgroupGetFreezerState(virCgroupPtr group, char **state);
int virCgroupRemove(virCgroupPtr group);
void virCgroupFree(virCgroupPtr *group);
+bool virCgroupMounted(virCgroupPtr cgroup, int controller);
#endif /* CGROUP_H */