XL/fs: ListMultipartUploads should list only requested entries. (#1668)

Fixes #1665

object-common-multipart.go

@@ -373,6 +373,12 @@ func listMetaBucketMultipartFiles(layer ObjectLayer, prefixPath string, markerPa
 				}
 				fileInfo.Name = path.Join(fi.Name, entry)
 				fileInfos = append(fileInfos, fileInfo)
+				newMaxKeys++
+				// If we have reached the maxKeys, it means we have listed
+				// everything that was requested. Return right here.
+				if newMaxKeys == maxKeys {
+					return
+				}
 			}
 		} else {
 			// We reach here for a non-recursive case non-leaf entry
@@ -385,7 +391,6 @@ func listMetaBucketMultipartFiles(layer ObjectLayer, prefixPath string, markerPa
 				fi.Name = path.Dir(fi.Name)
 			}
 			fileInfos = append(fileInfos, fi)
-		}
 			newMaxKeys++
 			// If we have reached the maxKeys, it means we have listed
 			// everything that was requested. Return right here.
@@ -393,11 +398,18 @@ func listMetaBucketMultipartFiles(layer ObjectLayer, prefixPath string, markerPa
 				return
 			}
 		}
+	}
 
 	// Return entries here.
 	return fileInfos, eof, nil
 }
 
+// FIXME: Currently the code sorts based on keyName/upload-id which is
+// in correct based on the S3 specs. According to s3 specs we are
+// supposed to only lexically sort keyNames and then for keyNames with
+// multiple upload ids should be sorted based on the initiated time.
+// Currently this case is not handled.
+
 // listMultipartUploadsCommon - lists all multipart uploads, common
 // function for both object layers.
 func listMultipartUploadsCommon(layer ObjectLayer, bucket, prefix, keyMarker, uploadIDMarker, delimiter string, maxUploads int) (ListMultipartsInfo, error) {