Fix StorageClass field in ListObject/ListObjectV2 response (#5766)

Fixes: #5754

cmd/api-response.go

@@ -339,7 +339,7 @@ func generateListObjectsV1Response(bucket, prefix, marker, delimiter string, max
 			content.ETag = "\"" + object.ETag + "\""
 		}
 		content.Size = object.Size
-		content.StorageClass = globalMinioDefaultStorageClass
+		content.StorageClass = object.StorageClass
 		content.Owner = owner
 		contents = append(contents, content)
 	}
@@ -385,7 +385,7 @@ func generateListObjectsV2Response(bucket, prefix, token, nextToken, startAfter,
 			content.ETag = "\"" + object.ETag + "\""
 		}
 		content.Size = object.Size
-		content.StorageClass = globalMinioDefaultStorageClass
+		content.StorageClass = object.StorageClass
 		content.Owner = owner
 		contents = append(contents, content)
 	}

cmd/object-api-datatypes.go

@@ -98,6 +98,9 @@ type ObjectInfo struct {
 	// by the Content-Type header field.
 	ContentEncoding string
 
+	// Specify object storage class
+	StorageClass string
+
 	// User-Defined metadata
 	UserDefined map[string]string
 

cmd/xl-v1-metadata.go

@@ -315,6 +315,13 @@ func (m xlMetaV1) ToObjectInfo(bucket, object string) ObjectInfo {
 	// All the parts per object.
 	objInfo.Parts = m.Parts
 
+	// Update storage class
+	if sc, ok := m.Meta[amzStorageClass]; ok {
+		objInfo.StorageClass = sc
+	} else {
+		objInfo.StorageClass = globalMinioDefaultStorageClass
+	}
+
 	// Success.
 	return objInfo
 }