lxc: Sync BlkioDevice values when setting them in cgroups

The problem here is that there are some values that kernel accepts, but
does not set them, for example 18446744073709551615 which acts the same
way as zero.  Let's do the same thing we do with other tuning options
and re-read them right after they are set in order to keep our internal
structures up-to-date.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/lxc/lxc_cgroup.c

@@ -117,27 +117,37 @@ static int virLXCCgroupSetupBlkioTune(virDomainDefPtr def,
 
             if (dev->weight &&
                 (virCgroupSetBlkioDeviceWeight(cgroup, dev->path,
-                                               dev->weight) < 0))
+                                               dev->weight) < 0 ||
+                 virCgroupGetBlkioDeviceWeight(cgroup, dev->path,
+                                               &dev->weight) < 0))
                 return -1;
 
             if (dev->riops &&
                 (virCgroupSetBlkioDeviceReadIops(cgroup, dev->path,
-                                                 dev->riops) < 0))
+                                                 dev->riops) < 0 ||
+                 virCgroupGetBlkioDeviceReadIops(cgroup, dev->path,
+                                                 &dev->riops) < 0))
                 return -1;
 
             if (dev->wiops &&
                 (virCgroupSetBlkioDeviceWriteIops(cgroup, dev->path,
-                                                  dev->wiops) < 0))
+                                                  dev->wiops) < 0 ||
+                 virCgroupGetBlkioDeviceWriteIops(cgroup, dev->path,
+                                                  &dev->wiops) < 0))
                 return -1;
 
             if (dev->rbps &&
                 (virCgroupSetBlkioDeviceReadBps(cgroup, dev->path,
-                                                dev->rbps) < 0))
+                                                dev->rbps) < 0 ||
+                 virCgroupGetBlkioDeviceReadBps(cgroup, dev->path,
+                                                &dev->rbps) < 0))
                 return -1;
 
             if (dev->wbps &&
                 (virCgroupSetBlkioDeviceWriteBps(cgroup, dev->path,
-                                                 dev->wbps) < 0))
+                                                 dev->wbps) < 0 ||
+                 virCgroupGetBlkioDeviceWriteBps(cgroup, dev->path,
+                                                 &dev->wbps) < 0))
                 return -1;
         }
     }

src/lxc/lxc_driver.c

@@ -2603,7 +2603,10 @@ lxcDomainSetBlkioParameters(virDomainPtr dom,
                     for (j = 0; j < ndevices; j++) {
                         if (virCgroupSetBlkioDeviceWeight(priv->cgroup,
                                                           devices[j].path,
-                                                          devices[j].weight) < 0) {
+                                                          devices[j].weight) < 0 ||
+                            virCgroupGetBlkioDeviceWeight(priv->cgroup,
+                                                          devices[j].path,
+                                                          &devices[j].weight) < 0) {
                             ret = -1;
                             break;
                         }
@@ -2612,7 +2615,10 @@ lxcDomainSetBlkioParameters(virDomainPtr dom,
                     for (j = 0; j < ndevices; j++) {
                         if (virCgroupSetBlkioDeviceReadIops(priv->cgroup,
                                                             devices[j].path,
-                                                            devices[j].riops) < 0) {
+                                                            devices[j].riops) < 0 ||
+                            virCgroupGetBlkioDeviceReadIops(priv->cgroup,
+                                                            devices[j].path,
+                                                            &devices[j].riops) < 0) {
                             ret = -1;
                             break;
                         }
@@ -2621,7 +2627,10 @@ lxcDomainSetBlkioParameters(virDomainPtr dom,
                     for (j = 0; j < ndevices; j++) {
                         if (virCgroupSetBlkioDeviceWriteIops(priv->cgroup,
                                                              devices[j].path,
-                                                             devices[j].wiops) < 0) {
+                                                             devices[j].wiops) < 0 ||
+                            virCgroupGetBlkioDeviceWriteIops(priv->cgroup,
+                                                             devices[j].path,
+                                                             &devices[j].wiops) < 0) {
                             ret = -1;
                             break;
                         }
@@ -2630,7 +2639,10 @@ lxcDomainSetBlkioParameters(virDomainPtr dom,
                     for (j = 0; j < ndevices; j++) {
                         if (virCgroupSetBlkioDeviceReadBps(priv->cgroup,
                                                            devices[j].path,
-                                                           devices[j].rbps) < 0) {
+                                                           devices[j].rbps) < 0 ||
+                            virCgroupGetBlkioDeviceReadBps(priv->cgroup,
+                                                           devices[j].path,
+                                                           &devices[j].rbps) < 0) {
                             ret = -1;
                             break;
                         }
@@ -2639,7 +2651,10 @@ lxcDomainSetBlkioParameters(virDomainPtr dom,
                     for (j = 0; j < ndevices; j++) {
                         if (virCgroupSetBlkioDeviceWriteBps(priv->cgroup,
                                                             devices[j].path,
-                                                            devices[j].wbps) < 0) {
+                                                            devices[j].wbps) < 0 ||
+                            virCgroupGetBlkioDeviceWriteBps(priv->cgroup,
+                                                            devices[j].path,
+                                                            &devices[j].wbps) < 0) {
                             ret = -1;
                             break;
                         }