Virtual_disk: add new negative case of discard_no_unref

VIRT-301835 - [virtual_disk][discard_no_unref][negative] Update device for guest with discard_no_unref attribute

Signed-off-by: Meina Li <[email protected]>

libvirt/tests/cfg/virtual_disks/virtual_disks_discard_no_unref.cfg

@@ -26,6 +26,10 @@
         - start_vm:
             check_qemu_pattern = '"discard":"${discard}","driver":"qcow2","discard-no-unref":${qemu_output}'
             expect_xml_line = 'discard_no_unref="${discard_no_unref}"'
+        - hotplug_disk:
+            only enable..with_discard_unmap.file_disk
+            hotplug = "yes"
+            check_libvirtd_log = '"driver":"qcow2","discard-no-unref":true'
         - define_invalid:
             only enable..with_discard_unmap.file_disk
             status_error = "yes"
@@ -35,8 +39,9 @@
                     expect_error = "unsupported configuration: 'discard_no_unref' only works with qcow2 disk format"
                 - readonly_mode:
                     expect_error = "unsupported configuration: 'discard_no_unref' is not compatible with read-only disk"
-        - hotplug_disk:
+        - update_negative:
             only enable..with_discard_unmap.file_disk
-            hotplug = "yes"
-            check_libvirtd_log = '"driver":"qcow2","discard-no-unref":true'
+            func_supported_since_libvirt_ver = (10, 5, 0)
+            status_error = "yes"
+            expect_error = "cannot modify field 'discard_no_unref' of the disk"
     disk_dict = {'type_name': '${disk_type}', 'driver': {'name': 'qemu', 'type': 'qcow2', 'discard': '${discard}', 'discard_no_unref': '${discard_no_unref}'}, 'target': {'dev': '${target_dev}'}}

libvirt/tests/src/virtual_disks/virtual_disks_discard_no_unref.py

@@ -126,6 +126,31 @@ def run_test_hotplug_disk(vm, params, test):
         test.fail("The target disk % can't be detached in guest." % target_dev)
 
 
+def run_test_update_negative(vm, params, test):
+    """
+    Scenario: update device for guest with discard_no_unref attribute
+
+    :param vm: vm instance
+    :param params: dict, test parameters
+    :param test: test object
+    """
+    vm_name = params.get("main_vm")
+    expect_error = params.get("expect_error")
+
+    test.log.debug("STEP1: start a guest.")
+    if not vm.is_alive():
+        vm.start()
+    test.log.debug("STEP2: prepare the disk xml.")
+    vmxml = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)
+    disk = vmxml.get_devices(device_type="disk")[0]
+    disk_driver = disk['driver']
+    disk_driver.update({'discard_no_unref': 'on'})
+    disk['driver'] = disk_driver
+    test.log.debug("STEP3: update the disk device.")
+    result = virsh.update_device(vm_name, disk.xml, debug=True)
+    libvirt.check_result(result, expect_error)
+
+
 def teardown_test(vm, vmxml, params, test):
     """
     :param vm: vm instance