Description of problem:
When OCS is set as default storage class and a VM is created from template (i.e using a golden image as source PVC), VM fails to start.
This is the default flow for VM from golden images using the CLI.

Version-Release number of selected component (if applicable):
virt-cdi-operator-container-v2.6.0-19

How reproducible:
100%

Steps to Reproduce:
1. Set OCS as default SC
2. Create an OCS golden image DV under openshift-virtualization-os-images ns 
3. Create a VM from common templates

Actual results:
VM fails to start:
  Warning  FailedDataVolumeCreate  3m27s (x20 over 58m)  virtualmachine-controller  Error creating DataVolume vm-from-golden-image-1611140157-9784682: admission webhook "datavolume-validate.cdi.kubevirt.io" denied the request:  source volumeMode (Block) and target volumeMode (Filesystem) do not match

- When a VM is created from common templates, only accessModes is provided in the template under dataVolumeTemplates.
The Storage class and volumeMode should be automatically filled based on cluster defaults (deafult SC and kubevirt-storage-class-defaults); in this case OCS configuration.

  dataVolumeTemplates:
  - apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: vm-from-golden-image-1611140157-9784682
    spec:
      pvc:
        accessModes:
        - ReadWriteMany
        resources:
          requests:
            storage: 30Gi
      source:
        pvc:
          name: fedora33
          namespace: openshift-virtualization-os-images


Expected results:
VM should be created and started successfully.

Additional info:

=============== Source DV ==============================
$ oc describe dv -n openshift-virtualization-os-images fedora33
Name:         fedora33
Namespace:    openshift-virtualization-os-images
Labels:       <none>
Annotations:  <none>
API Version:  cdi.kubevirt.io/v1beta1
Kind:         DataVolume
Metadata:
  Creation Timestamp:  2021-01-20T10:49:18Z
  Generation:          198
  Managed Fields:
    API Version:  cdi.kubevirt.io/v1beta1
    Fields Type:  FieldsV1
    fieldsV1:
      f:spec:
        .:
        f:contentType:
        f:pvc:
          .:
          f:accessModes:
          f:resources:
            .:
            f:requests:
              .:
              f:storage:
          f:storageClassName:
          f:volumeMode:
        f:source:
          .:
          f:http:
            .:
            f:url:
    Manager:      OpenAPI-Generator
    Operation:    Update
    Time:         2021-01-20T10:49:18Z
    API Version:  cdi.kubevirt.io/v1beta1
    Fields Type:  FieldsV1
    fieldsV1:
      f:status:
        .:
        f:conditions:
        f:phase:
        f:progress:
    Manager:         virt-cdi-controller
    Operation:       Update
    Time:            2021-01-20T10:49:18Z
  Resource Version:  1172823
  Self Link:         /apis/cdi.kubevirt.io/v1beta1/namespaces/openshift-virtualization-os-images/datavolumes/fedora33
  UID:               c45cc67c-b35a-46b9-a2d8-6b9cc841f39d
Spec:
  Content Type:  kubevirt
  Pvc:
    Access Modes:
      ReadWriteMany
    Resources:
      Requests:
        Storage:         10Gi
    Storage Class Name:  ocs-storagecluster-ceph-rbd
    Volume Mode:         Block
  Source:
    Http:
      URL:  http://cnv-qe-server.rhevdev.lab.eng.rdu2.redhat.com/files/cnv-tests/fedora-images/Fedora-Cloud-Base-33-1.2.x86_64.qcow2
Status:
  Conditions:
    Last Heartbeat Time:   2021-01-20T10:49:19Z
    Last Transition Time:  2021-01-20T10:49:19Z
    Message:               PVC fedora33 Bound
    Reason:                Bound
    Status:                True
    Type:                  Bound
    Last Heartbeat Time:   2021-01-20T10:55:56Z
    Last Transition Time:  2021-01-20T10:55:56Z
    Status:                True
    Type:                  Ready
    Last Heartbeat Time:   2021-01-20T10:55:56Z
    Last Transition Time:  2021-01-20T10:55:56Z
    Message:               Import Complete
    Reason:                Completed
    Status:                False
    Type:                  Running
  Phase:                   Succeeded
  Progress:                100.0%
Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  Pending           66m   datavolume-controller  PVC fedora33 Pending
  Normal  Bound             66m   datavolume-controller  PVC fedora33 Bound
  Normal  ImportScheduled   66m   datavolume-controller  Import into fedora33 scheduled
  Normal  ImportInProgress  66m   datavolume-controller  Import into fedora33 in progress
  Normal  ImportSucceeded   60m   datavolume-controller  Successfully imported into PVC fedora33


================ Storage class config =============================
$ oc get sc
NAME                                    PROVISIONER                             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
csi-manila-ceph                         manila.csi.openstack.org                Delete          Immediate              false                  24h
hostpath-provisioner                    kubevirt.io/hostpath-provisioner        Delete          WaitForFirstConsumer   false                  23h
local-block                             kubernetes.io/no-provisioner            Delete          WaitForFirstConsumer   false                  23h
nfs                                     kubernetes.io/no-provisioner            Delete          Immediate              false                  23h
ocs-storagecluster-ceph-rbd (default)   openshift-storage.rbd.csi.ceph.com      Delete          Immediate              true                   23h
ocs-storagecluster-ceph-rgw             openshift-storage.ceph.rook.io/bucket   Delete          Immediate              false                  23h
ocs-storagecluster-cephfs               openshift-storage.cephfs.csi.ceph.com   Delete          Immediate              true                   23h
openshift-storage.noobaa.io             openshift-storage.noobaa.io/obc         Delete          Immediate              false                  7h6m
standard                                kubernetes.io/cinder                    Delete          WaitForFirstConsumer   true                   24h
standard-csi                            cinder.csi.openstack.org                Delete          WaitForFirstConsumer   true                   24h

====================== kubevirt-storage-class-defaults =======================
$ oc get cm -n openshift-cnv kubevirt-storage-class-defaults -oyaml
apiVersion: v1
data:
  accessMode: ReadWriteOnce
  local-sc.accessMode: ReadWriteOnce
  local-sc.volumeMode: Filesystem
  ocs-storagecluster-ceph-rbd.accessMode: ReadWriteMany
  ocs-storagecluster-ceph-rbd.volumeMode: Block
  volumeMode: Filesystem
kind: ConfigMap


================ VM yaml =============================
apiVersion: kubevirt.io/v1alpha3
kind: VirtualMachine
metadata:
  annotations:
    vm.kubevirt.io/flavor: tiny
    vm.kubevirt.io/os: fedora
    vm.kubevirt.io/validations: "[\n  {\n    \"name\": \"minimal-required-memory\"\
      ,\n    \"path\": \"jsonpath::.spec.domain.resources.requests.memory\",\n   \
      \ \"rule\": \"integer\",\n    \"message\": \"This VM requires more memory.\"\
      ,\n    \"min\": 1073741824\n  }\n]\n"
    vm.kubevirt.io/workload: server
  labels:
    app: vm-from-golden-image-1611140157-9784682
    vm.kubevirt.io/template: fedora-server-tiny
    vm.kubevirt.io/template.namespace: openshift
    vm.kubevirt.io/template.revision: '1'
    vm.kubevirt.io/template.version: v0.13.1
  name: vm-from-golden-image-1611140157-9784682
spec:
  dataVolumeTemplates:
  - apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: vm-from-golden-image-1611140157-9784682
    spec:
      pvc:
        accessModes:
        - ReadWriteMany
        resources:
          requests:
            storage: 30Gi
      source:
        pvc:
          name: fedora33
          namespace: openshift-virtualization-os-images
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/domain: vm-from-golden-image-1611140157-9784682
        kubevirt.io/size: tiny
        kubevirt.io/vm: vm-from-golden-image-1611140157-9784682
    spec:
      domain:
        cpu:
          cores: 1
          sockets: 1
          threads: 1
        devices:
          disks:
          - disk:
              bus: virtio
            name: vm-from-golden-image-1611140157-9784682
          - disk:
              bus: virtio
            name: cloudinitdisk
          interfaces:
          - masquerade: {}
            name: default
          networkInterfaceMultiqueue: true
          rng: {}
        machine:
          type: pc-q35-rhel8.3.0
        resources:
          requests:
            memory: 1Gi
      evictionStrategy: LiveMigrate
      networks:
      - name: default
        pod: {}
      terminationGracePeriodSeconds: 180
      volumes:
      - dataVolume:
          name: vm-from-golden-image-1611140157-9784682
        name: vm-from-golden-image-1611140157-9784682
      - cloudInitNoCloud:
          userData: '#cloud-config

            user: fedora

            password: fedora

            chpasswd: { expire: False }'
        name: cloudinitdisk

================ VM describe =============================
$ oc describe vm -n templates-golden-images-test-common-templates-data-volumes
Name:         vm-from-golden-image-1611140157-9784682
Namespace:    templates-golden-images-test-common-templates-data-volumes
Labels:       app=vm-from-golden-image-1611140157-9784682
              vm.kubevirt.io/template=fedora-server-tiny
              vm.kubevirt.io/template.namespace=openshift
              vm.kubevirt.io/template.revision=1
              vm.kubevirt.io/template.version=v0.13.1
Annotations:  kubevirt.io/latest-observed-api-version: v1alpha3
              kubevirt.io/storage-observed-api-version: v1alpha3
              vm.kubevirt.io/flavor: tiny
              vm.kubevirt.io/os: fedora
              vm.kubevirt.io/validations:
                [
                  {
                    "name": "minimal-required-memory",
                    "path": "jsonpath::.spec.domain.resources.requests.memory",
                    "rule": "integer",
                    "message": "This VM requires more memory.",
                    "min": 1073741824
                  }
                ]
              vm.kubevirt.io/workload: server
API Version:  kubevirt.io/v1alpha3
Kind:         VirtualMachine
Metadata:
  Creation Timestamp:  2021-01-20T10:55:58Z
  Finalizers:
    k8s.v1.cni.cncf.io/kubeMacPool
  Generation:  2
  Managed Fields:
    API Version:  kubevirt.io/v1alpha3
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          .:
          f:vm.kubevirt.io/flavor:
          f:vm.kubevirt.io/os:
          f:vm.kubevirt.io/validations:
          f:vm.kubevirt.io/workload:
        f:labels:
          .:
          f:app:
          f:vm.kubevirt.io/template:
          f:vm.kubevirt.io/template.namespace:
          f:vm.kubevirt.io/template.revision:
          f:vm.kubevirt.io/template.version:
      f:spec:
        .:
        f:dataVolumeTemplates:
        f:template:
          .:
          f:metadata:
            .:
            f:labels:
              .:
              f:kubevirt.io/domain:
              f:kubevirt.io/size:
              f:kubevirt.io/vm:
          f:spec:
            .:
            f:domain:
              .:
              f:cpu:
                .:
                f:cores:
                f:sockets:
                f:threads:
              f:devices:
                .:
                f:disks:
                f:interfaces:
                f:networkInterfaceMultiqueue:
                f:rng:
              f:machine:
                .:
                f:type:
              f:resources:
                .:
                f:requests:
                  .:
                  f:memory:
            f:evictionStrategy:
            f:networks:
            f:terminationGracePeriodSeconds:
            f:volumes:
    Manager:      OpenAPI-Generator
    Operation:    Update
    Time:         2021-01-20T10:55:58Z
    API Version:  kubevirt.io/v1alpha3
    Fields Type:  FieldsV1
    fieldsV1:
      f:spec:
        f:running:
    Manager:      virt-api
    Operation:    Update
    Time:         2021-01-20T10:55:59Z
    API Version:  kubevirt.io/v1alpha3
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          f:kubevirt.io/latest-observed-api-version:
          f:kubevirt.io/storage-observed-api-version:
      f:status:
        .:
        f:conditions:
        f:volumeSnapshotStatuses:
    Manager:         virt-controller
    Operation:       Update
    Time:            2021-01-20T10:55:59Z
  Resource Version:  1172874
  Self Link:         /apis/kubevirt.io/v1alpha3/namespaces/templates-golden-images-test-common-templates-data-volumes/virtualmachines/vm-from-golden-image-1611140157-9784682
  UID:               ca850194-4bf6-452a-a902-2f6cd54e58ae
Spec:
  Data Volume Templates:
    API Version:  cdi.kubevirt.io/v1beta1
    Kind:         DataVolume
    Metadata:
      Creation Timestamp:  <nil>
      Name:                vm-from-golden-image-1611140157-9784682
    Spec:
      Pvc:
        Access Modes:
          ReadWriteMany
        Resources:
          Requests:
            Storage:  30Gi
      Source:
        Pvc:
          Name:       fedora33
          Namespace:  openshift-virtualization-os-images
  Running:            true
  Template:
    Metadata:
      Creation Timestamp:  <nil>
      Labels:
        kubevirt.io/domain:  vm-from-golden-image-1611140157-9784682
        kubevirt.io/size:    tiny
        kubevirt.io/vm:      vm-from-golden-image-1611140157-9784682
    Spec:
      Domain:
        Cpu:
          Cores:    1
          Sockets:  1
          Threads:  1
        Devices:
          Disks:
            Disk:
              Bus:  virtio
            Name:   vm-from-golden-image-1611140157-9784682
            Disk:
              Bus:  virtio
            Name:   cloudinitdisk
          Interfaces:
            Mac Address:  02:7e:45:00:00:68
            Masquerade:
            Name:                        default
          Network Interface Multiqueue:  true
          Rng:
        Machine:
          Type:  pc-q35-rhel8.3.0
        Resources:
          Requests:
            Memory:       1Gi
      Eviction Strategy:  LiveMigrate
      Networks:
        Name:  default
        Pod:
      Termination Grace Period Seconds:  180
      Volumes:
        Data Volume:
          Name:  vm-from-golden-image-1611140157-9784682
        Name:    vm-from-golden-image-1611140157-9784682
        Cloud Init No Cloud:
          User Data:  #cloud-config
user: fedora
password: fedora
chpasswd: { expire: False }
        Name:  cloudinitdisk
Status:
  Conditions:
    Last Probe Time:       <nil>
    Last Transition Time:  2021-01-20T10:55:59Z
    Message:               Failed to create DataVolume: admission webhook "datavolume-validate.cdi.kubevirt.io" denied the request:  source volumeMode (Block) and target volumeMode (Filesystem) do not match
    Reason:                FailedCreate
    Status:                True
    Type:                  Failure
  Volume Snapshot Statuses:
    Enabled:  false
    Name:     vm-from-golden-image-1611140157-9784682
    Reason:   DV 'templates-golden-images-test-common-templates-data-volumes/vm-from-golden-image-1611140157-9784682' not found
    Enabled:  false
    Name:     cloudinitdisk
    Reason:   Volume type does not suport snapshots
Events:
  Type     Reason                  Age                  From                       Message
  ----     ------                  ----                 ----                       -------
  Warning  FailedDataVolumeCreate  104s (x18 over 23m)  virtualmachine-controller  Error creating DataVolume vm-from-golden-image-1611140157-9784682: admission webhook "datavolume-validate.cdi.kubevirt.io" denied the request:  source volumeMode (Block) and target volumeMode (Filesystem) do not match



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