fix: set LHv2 DiskDriver to "auto" if unset

We need to force DiskDriver to "auto" if it's not explicitly set,
because Longhorn also does that internally.  If we don't do this,
the subsequent reflect.DeepEqual() in LonghornV2Provisioner.Update()
will always fail because we have an empty string, but the LHN CR
will have it set to "auto" which results in a weird resync loop.

Related issue: harvester/harvester#6709

Signed-off-by: Tim Serong <tserong@suse.com>

pkg/provisioner/longhornv2.go

@@ -30,6 +30,14 @@ func NewLHV2Provisioner(
 	if !cacheDiskTags.Initialized() {
 		return nil, errors.New(ErrorCacheDiskTagsNotInitialized)
 	}
+	if device.Spec.Provisioner.Longhorn.DiskDriver == longhornv1.DiskDriverNone {
+		// We need to force DiskDriver to "auto" if it's not explicitly set,
+		// because Longhorn also does that internally.  If we don't do it
+		// here, the subsequent reflect.DeepEqual() in our Update() function
+		// will always fail because we have an empty string, but the LHN CR
+		// has it set to "auto" which results in a weird resync loop.
+		device.Spec.Provisioner.Longhorn.DiskDriver = longhornv1.DiskDriverAuto
+	}
 	baseProvisioner := &provisioner{
 		name:      TypeLonghornV2,
 		blockInfo: block,
@@ -85,17 +93,14 @@ func (p *LonghornV2Provisioner) Provision() (isRequeueNeeded bool, err error) {
 		return false, err
 	}
 
-	// If diskDriver is an empty string, longhorn will map that to "auto" internally
-	diskDriver := p.device.Spec.Provisioner.Longhorn.DiskDriver
-
 	diskSpec := longhornv1.DiskSpec{
 		Type:              longhornv1.DiskTypeBlock,
 		Path:              devPath,
 		AllowScheduling:   true,
 		EvictionRequested: false,
 		StorageReserved:   0,
 		Tags:              tags,
-		DiskDriver:        diskDriver,
+		DiskDriver:        p.device.Spec.Provisioner.Longhorn.DiskDriver,
 	}
 
 	// We're intentionally not trying to sync disk tags from longhorn if the