Materialize per-layer artifacts with explicit whiteout handling

lib/images/disk_usage.go

@@ -3,8 +3,10 @@ package images
 import (
 	"encoding/json"
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
+	"strings"
 	"syscall"
 )
 
@@ -82,6 +84,38 @@ func totalReadyImageBytesFromMetadata(imagesDir string) (int64, error) {
 	return total, nil
 }
 
+// totalLayerArtifactBytesFromFilesystem sums materialized layer artifacts.
+func totalLayerArtifactBytesFromFilesystem(layersDir string) (int64, error) {
+	var total int64
+	err := filepath.WalkDir(layersDir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			if os.IsNotExist(err) {
+				return nil
+			}
+			return err
+		}
+		if d.IsDir() {
+			if strings.HasPrefix(d.Name(), ".") && path != layersDir {
+				return filepath.SkipDir
+			}
+			return nil
+		}
+		if !strings.HasPrefix(d.Name(), "layer.") {
+			return nil
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		total += info.Size()
+		return nil
+	})
+	if err != nil {
+		return 0, fmt.Errorf("walk layer artifacts: %w", err)
+	}
+	return total, nil
+}
+
 // totalOCICacheBlobBytesFromFilesystem sums blob sizes directly from the OCI cache blob store.
 // This counts the actual bytes on disk, including any blob files that are currently
 // present but no longer referenced by the OCI layout index.
@@ -158,7 +192,11 @@ func (m *manager) computeDiskUsageTotals() (int64, int64, error) {
 	if err != nil {
 		return 0, 0, err
 	}
-	return readyImageBytes, ociCacheBytes, nil
+	layerArtifactBytes, err := totalLayerArtifactBytesFromFilesystem(m.paths.ImageLayersDir())
+	if err != nil {
+		return 0, 0, err
+	}
+	return readyImageBytes, ociCacheBytes + layerArtifactBytes, nil
 }
 
 func totalRootfsBytesInDigestDir(digestDir string) (int64, error) {

lib/images/disk_usage_test.go

@@ -64,6 +64,26 @@ func TestTotalReadyImageBytesFromMetadata_DeduplicatesMalformedAliases(t *testin
 	require.Equal(t, int64(len("shared-rootfs")), total)
 }
 
+func TestTotalLayerArtifactBytesFromFilesystem(t *testing.T) {
+	t.Parallel()
+
+	layersDir := t.TempDir()
+	digestDir := filepath.Join(layersDir, "a", "b")
+	require.NoError(t, os.MkdirAll(digestDir, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(digestDir, "layer.erofs"), []byte("erofs"), 0o644))
+	require.NoError(t, os.WriteFile(filepath.Join(digestDir, "layer.ext4"), []byte("ext4"), 0o644))
+	require.NoError(t, os.WriteFile(filepath.Join(digestDir, "artifact.erofs.json"), []byte("record"), 0o644))
+
+	// In-progress temp dirs should be skipped.
+	unpackDir := filepath.Join(digestDir, ".unpack-tmp")
+	require.NoError(t, os.MkdirAll(unpackDir, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(unpackDir, "layer.bin"), []byte("unpacked-content"), 0o644))
+
+	total, err := totalLayerArtifactBytesFromFilesystem(layersDir)
+	require.NoError(t, err)
+	require.Equal(t, int64(len("erofs")+len("ext4")), total)
+}
+
 func TestTotalReadyImageBytesFromMetadata_UsesRootfsFallbackForReadyImageWithoutSize(t *testing.T) {
 	t.Parallel()