Correct wrong check of resulting image sparsiness

The first issue is that we look at content size since 2168,
which is not beneficial in the sparseness check as opposed to disk usage.

The second issue is that the check we have in tests for sparsiness is not honest because of the "equal to" part.
The virtual size has to be strictly greater than the content
(as the content is displayed by tools that understand sparseness).

Signed-off-by: Alex Kalenyuk <[email protected]>

tests/framework/pvc.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"strconv"
 	"strings"
 	"time"
 
@@ -284,22 +283,12 @@ func (f *Framework) VerifyBlankDisk(namespace *k8sv1.Namespace, pvc *k8sv1.Persi
 // VerifySparse checks a disk image being sparse after creation/resize.
 func (f *Framework) VerifySparse(namespace *k8sv1.Namespace, pvc *k8sv1.PersistentVolumeClaim, imagePath string) (bool, error) {
 	var info image.ImgInfo
-	var imageContentSize int64
 	err := f.GetImageInfo(namespace, pvc, imagePath, &info)
 	if err != nil {
 		return false, err
 	}
-	// qemu-img info gives us ActualSize but that is size on disk
-	// which isn't important to us in this comparison; we compare content size
-	err = f.GetImageContentSize(namespace, pvc, imagePath, &imageContentSize)
-	if err != nil {
-		return false, err
-	}
-	if info.ActualSize-imageContentSize >= units.MiB {
-		return false, fmt.Errorf("Diff between content size %d and size on disk %d is significant, something's not right", imageContentSize, info.ActualSize)
-	}
-	fmt.Fprintf(ginkgo.GinkgoWriter, "INFO: VerifySparse comparison: Virtual: %d vs Content: %d\n", info.VirtualSize, imageContentSize)
-	return info.VirtualSize >= imageContentSize, nil
+	// The content size of a sparse image is significantly lower than the image's virtual size
+	return info.VirtualSize-info.ActualSize >= units.MiB, nil
 }
 
 // VerifyFSOverhead checks whether virtual size is smaller than actual size. That means FS Overhead has been accounted for.
@@ -546,26 +535,6 @@ func (f *Framework) GetImageInfo(namespace *k8sv1.Namespace, pvc *k8sv1.Persiste
 	return err
 }
 
-// GetImageContentSize returns the content size (as opposed to size on disk) of an image
-func (f *Framework) GetImageContentSize(namespace *k8sv1.Namespace, pvc *k8sv1.PersistentVolumeClaim, imagePath string, imageSize *int64) error {
-	cmd := fmt.Sprintf("du -s --apparent-size -B 1 %s | cut -f 1", imagePath)
-
-	_, err := f.verifyInPod(namespace, pvc, cmd, func(output, stderr string) (bool, error) {
-		fmt.Fprintf(ginkgo.GinkgoWriter, "CMD (%s) output %s\n", cmd, output)
-
-		size, err := strconv.ParseInt(output, 10, 64)
-		if err != nil {
-			klog.Errorf("Invalid image content size:\n%s\n", output)
-			return false, err
-		}
-		*imageSize = size
-
-		return true, nil
-	})
-
-	return err
-}
-
 func (f *Framework) startVerifierPod(namespace *k8sv1.Namespace, pvc *k8sv1.PersistentVolumeClaim) (*k8sv1.Pod, error) {
 	var executorPod *k8sv1.Pod
 	var err error