Author: Klaus Post <******@****.***>
Date:   Thu Nov 18 12:15:22 2021 -0800

    Improve performance on multiple versions (#13573)
```

- A fix must be a valid fix that was reproduced and seen in a customer environment, for example.

```
commit 886262e58af77ebc7c836ef587c08544e9a0c271
Author: Harshavardhana <******@****.***>
Date:   Wed Nov 17 15:49:12 2021 -0800

			// Verify if date headers are set, if not reject the request
			amzDate, errCode := parseAmzDateHeader(r)
			if errCode != ErrNone {
				if ok {
					tc.FuncName = "handler.Auth"
					tc.ResponseRecorder.LogErrBody = true
				}

				// All our internal APIs are sensitive towards Date
				// header, for all requests where Date header is not
				// present we will reject such clients.

	},
	ErrMalformedDate: {
		Code:           "MalformedDate",
		Description:    "Invalid date format header, expected to be in ISO8601, RFC1123 or RFC1123Z time format.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrMalformedPresignedDate: {
		Code:           "AuthorizationQueryParametersError",
		Description:    "X-Amz-Date must be in the ISO8601 Long Format \"yyyyMMdd'T'HHmmss'Z'\"",
		HTTPStatusCode: http.StatusBadRequest,

	// can reach that size according to https://aws.amazon.com/articles/1434
	maxFormFieldSize = int64(1 * humanize.MiByte)

	// The maximum allowed time difference between the incoming request
	// date and server date during signature verification.
	globalMaxSkewTime = 15 * time.Minute // 15 minutes skew allowed.

	// GlobalStaleUploadsExpiry - Expiry duration after which the uploads in multipart,
	// tmp directory are deemed stale.

      or a Contribution incorporated within the Work constitutes direct
      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without

		// (6) Should error if the request is not ready yet, ie X-Amz-Date is in the future.
		{
			queryParams: map[string]string{
				"X-Amz-Algorithm":      signV4Algorithm,
				"X-Amz-Date":           now.Add(1 * time.Hour).Format(iso8601Format),
				"X-Amz-Expires":        "60",
				"X-Amz-Signature":      "badsignature",
				"X-Amz-SignedHeaders":  "host;x-amz-content-sha256;x-amz-date",

		canonicalHeaders += "\n"
	}

	date := expires // Date is set to expires date for presign operations.
	if date == "" {
		// If expires date is empty then request header Date is used.
		date = headers.Get(xhttp.Date)
	}

	// From the Amazon docs:
	//
	// StringToSign = HTTP-Verb + "\n" +
	// 	 Content-Md5 + "\n" +
	//	 Content-Type + "\n" +
	//	 Date/Expires + "\n" +
	//	 CanonicalizedProtocolHeaders +

type preSignValues struct {
	signValues
	Date    time.Time
	Expires time.Duration
}

// Parses signature version '4' query string of the following form.
//
//	querystring = X-Amz-Algorithm=algorithm
//	querystring += &X-Amz-Credential= urlencode(accessKey + '/' + credential_scope)
//	querystring += &X-Amz-Date=date
//	querystring += &X-Amz-Expires=timeout interval

	// Add the algorithm condition, only accept AWS SignV4 Sha256.
	algorithmConditionStr := `["eq", "$x-amz-algorithm", "AWS4-HMAC-SHA256"]`
	// Add the date condition, only accept the current date.
	dateConditionStr := fmt.Sprintf(`["eq", "$x-amz-date", "%s"]`, t.Format(iso8601DateFormat))
	// Add the credential string, only accept the credential passed.

Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin
X-Amz-Bucket-Region: us-east-1
X-Minio-Write-Quorum: 3
X-Amz-Request-Id: 16239D6AB80EBECF
X-Xss-Protection: 1; mode=block
Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Cluster-readable probe

The reply is '200 OK' if cluster has read quorum if not it returns '503 Service Unavailable'.

```
curl http://minio1:9001/minio/health/cluster/read