lxd/storage: Get volume total size regardless of driver

When driver does not support getting the volume usage, we are returning prematurely and not getting the volume total size, even when it is possible.

Signed-off-by: hamistao <[email protected]>

lxd/storage/backend_lxd.go

@@ -3261,12 +3261,14 @@ func (b *lxdBackend) GetInstanceUsage(inst instance.Instance) (*VolumeUsage, err
 	volStorageName := project.Instance(inst.Project().Name, inst.Name())
 	vol := b.GetVolume(volType, contentType, volStorageName, dbVol.Config)
 
-	// Get the usage.
+	// Get the usage
+	// If storage driver does not support getting the volume usage, proceed getting the total.
 	size, err := b.driver.GetVolumeUsage(vol)
-	if err != nil {
+	if err != nil && !errors.Is(err, drivers.ErrNotSupported) {
 		return nil, err
 	}
 
+	// If driver does not support getting volume usage, this value would be -1.
 	val.Used = size
 
 	// Get the total size.