r.Header.Set("delimiter", SlashSeparator)

	// Check if we are asked to return prefix usage
	enablePrefixUsage := r.Form.Get("prefix-usage") == "true"

	isAllowedAccess := func(bucketName string) (rd, wr bool) {
		if globalIAMSys.IsAllowed(policy.Args{
			AccountName:     cred.AccessKey,
			Groups:          cred.Groups,
			Action:          policy.ListBucketAction,