fi.SetTierFreeVersionID(mustGetUUID())
			// delete this version leading to a free version
			xl.DeleteVersion(fi)
			freeVersionIDs = append(freeVersionIDs, fi.TierFreeVersionID())
			allVersionIDs = append(allVersionIDs, fi.TierFreeVersionID())
		} else {
			versions = append(versions, fi)
			allVersionIDs = append(allVersionIDs, fi.VersionID)
		}
	}
	buf, err := xl.AppendTo(nil)
	if err != nil {

	if fi.Metadata == nil {
		fi.Metadata = make(map[string]string)
	}
	fi.Metadata[ReservedMetadataPrefixLower+tierFVID] = versionID
}

// TierFreeVersionID returns the free-version's version id.
func (fi *FileInfo) TierFreeVersionID() string {
	return fi.Metadata[ReservedMetadataPrefixLower+tierFVID]
}

// SetTierFreeVersion sets fi as a free-version. This method is used by

	}
	// check inline before overwriting metadata.
	inlineData := fi.InlineData()

	fi.Metadata = srcInfo.UserDefined
	srcInfo.UserDefined["etag"] = srcInfo.ETag

	freeVersionID := fi.TierFreeVersionID()
	freeVersionMarker := fi.TierFreeVersion()

	// Update `xl.meta` content on each disks.
	for index := range metaArr {
		if metaArr[index].IsValid() {
			metaArr[index].ModTime = modTime