etags = make([]string, len(partsMetadata))
	vidMap := map[string]int{}
	for index, metadata := range partsMetadata {
		if errs[index] != nil {
			continue
		}
		vid := metadata.VersionID
		if metadata.VersionID == "" {
			vid = nullVersionID
		}
		vidMap[vid]++
		etags[index] = metadata.Metadata["etag"]
	}

	for _, count := range vidMap {
		// do we have enough common versions