[libvirt] [PATCH 4/4] qemu: command: Don't allow setting 'group_name' alone

[Peter Krempa]

The disk tuning group parameter is ignored by qemu if no other
throttling options are set. Reject such configuration, since the name
would not be honored after setting parameters via the live tuning API.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1433180
---
 src/qemu/qemu_command.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 76c915ab6..9760fb10f 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -1259,12 +1259,23 @@ qemuCheckDiskConfigBlkdeviotune(virDomainDiskDefPtr disk,
     }

     /* block I/O group 2.4 */
-    if (disk->blkdeviotune.group_name &&
-        !virQEMUCapsGet(qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_GROUP)) {
-        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                       _("the block I/O throttling group parameter is "
-                         "not supported with this QEMU binary"));
-        return -1;
+    if (disk->blkdeviotune.group_name) {
+        if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_GROUP)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("the block I/O throttling group parameter is "
+                             "not supported with this QEMU binary"));
+            return -1;
+        }
+
+        /* group_name by itself is ignored by qemu */
+        if (!qemuDiskConfigBlkdeviotuneHasBasic(disk) &&
+            !qemuDiskConfigBlkdeviotuneHasMax(disk) &&
+            !qemuDiskConfigBlkdeviotuneHasMaxLength(disk)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("group_name can be configured only together with "
+                             "settings"));
+            return -1;
+        }
     }

     /* block I/O throttling length 2.6 */
-- 
2.12.0