scratch pvc is smaller than the main PVC which cause failuer in creating/importing dv with preallocation": Tru

cnv 4.20 gcnv

100% reproducable 

1.deploy gcnv cluster

2. create a dv with followin param (with "preallocation": True)


"dv_name": "cnv-5512",
"image": RHEL_LATEST["image_path"],
"dv_size": Images.Rhel.DEFAULT_DV_SIZE,
"preallocation": True,

here is example:
oc get dv cnv-5512 -n test-disk-preallocation -o yaml
apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  annotations:
    cdi.kubevirt.io/storage.usePopulator: "true"
  creationTimestamp: "2025-07-30T21:16:58Z"
  generation: 1
  name: cnv-5512
  namespace: test-disk-preallocation
  resourceVersion: "2207841"
  uid: d6e04849-dc0c-414a-9d9b-2e1c3fc35553
spec:
  contentType: kubevirt
  preallocation: true
  source:
    http:
      certConfigMap: artifactory-configmap
      secretRef: cnv-tests-artifactory-secret
      url: https://ibmc.artifactory.cnv-qe.rhood.us/artifactory/cnv-qe-server-local/cnv-tests/rhel-images/rhel-96.qcow2
  storage:
    resources:
      requests:
        storage: 20Gi
    storageClassName: gcnv-flex
status:
  claimName: cnv-5512
  conditions:
  - lastHeartbeatTime: "2025-07-30T21:16:58Z"
    lastTransitionTime: "2025-07-30T21:16:58Z"
    message: PVC cnv-5512 Pending
    reason: Pending
    status: "False"
    type: Bound
  - lastHeartbeatTime: "2025-07-30T21:18:02Z"
    lastTransitionTime: "2025-07-30T21:16:58Z"
    reason: TransferRunning
    status: "False"
    type: Ready
  - lastHeartbeatTime: "2025-07-30T21:17:44Z"
    lastTransitionTime: "2025-07-30T21:17:44Z"
    reason: Pod is running
    status: "True"
    type: Running
  phase: ImportInProgress
  progress: 95.53%




 3.wait for dv sucess and pvc bound

dv remains stuck and never sucess 
oc get dv -A
NAMESPACE                 NAME       PHASE              PROGRESS   RESTARTS   AGE
test-disk-preallocation   cnv-5512   ImportInProgress   95.53%                16m


oc get pvc -A
NAMESPACE                 NAME                                                 STATUS    VOLUME                                     CAPACITY      ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
test-disk-preallocation   cnv-5512                                             Pending                                                                           gcnv-flex      <unset>                 16m
test-disk-preallocation   prime-d5693159-fab0-4ac4-be1d-3a6f48770e06           Bound     pvc-d21f1c87-9f18-4f08-aec0-3d8536f06a72   22655952487   RWX            gcnv-flex      <unset>                 16m
test-disk-preallocation   prime-d5693159-fab0-4ac4-be1d-3a6f48770e06-scratch   Bound     pvc-b93d9185-53d5-4ed2-afa1-de42a39f6ddc   21607Mi       RWO            gcnv-flex      <unset>                 16m

dv sucess 

from importer log:

 Available space less than requested size, resizing image to available space 21372076032.
I0730 20:56:31.205366       1 data-processor.go:354] Expanding image size to: 21372076032
I0730 20:56:31.205372       1 qemu.go:364] Adding preallocation method: [--preallocation=falloc]
I0730 20:56:31.205393       1 qemu.go:368] Attempting preallocation method, qemu-img args: [resize --preallocation=falloc -f raw /data/disk.img 21372076032]




in differet sc providor (ocs-storagecluster-cephfs) I see scratch pvc is way to larger than main pvc

test-disk-preallocation              cnv-5512                                                       Pending                                                                        ocs-storagecluster-cephfs   <unset>                 3m37s
test-disk-preallocation              prime-51710615-f894-47bc-9af4-3283a51e9469                     Bound     pvc-0f0aaae7-35f3-4332-892f-673f8c2c4221   22Gi       RWX            ocs-storagecluster-cephfs   <unset>                 3m37s
test-disk-preallocation              prime-51710615-f894-47bc-9af4-3283a51e9469-scratch             Bound     pvc-190e8cee-99b6-4077-8f9d-9c3ee945c381   149Gi      RWO            hostpath-csi-basic          <unset>                 3m26s