fix return proper error for OperationTimedout (#9117)

OperationTimedout error occurs when locking
timesout, trying to acquire a lock. This
error should be returned appropriately to
the client with http status "408" (request timedout)

This translation was broken, fix it.

cmd/api-errors.go

@@ -1641,7 +1641,7 @@ func toAPIErrorCode(ctx context.Context, err error) (apiErr APIErrorCode) {
 		apiErr = ErrKMSNotConfigured
 	case crypto.ErrKMSAuthLogin:
 		apiErr = ErrKMSAuthFailure
-	case errOperationTimedOut, context.Canceled, context.DeadlineExceeded:
+	case context.Canceled, context.DeadlineExceeded:
 		apiErr = ErrOperationTimedOut
 	case errDiskNotFound:
 		apiErr = ErrSlowDown
@@ -1769,6 +1769,8 @@ func toAPIErrorCode(ctx context.Context, err error) (apiErr APIErrorCode) {
 		apiErr = ErrOverlappingFilterNotification
 	case *event.ErrUnsupportedConfiguration:
 		apiErr = ErrUnsupportedNotification
+	case OperationTimedOut:
+		apiErr = ErrOperationTimedOut
 	case BackendDown:
 		apiErr = ErrBackendDown
 	case ObjectNameTooLong:

cmd/typed-errors.go

@@ -50,9 +50,6 @@ var errRPCAPIVersionUnsupported = errors.New("Unsupported rpc API version")
 // errServerTimeMismatch - server times are too far apart.
 var errServerTimeMismatch = errors.New("Server times are too far apart")
 
-// errOperationTimedOut
-var errOperationTimedOut = errors.New("Operation timed out")
-
 // errInvalidBucketName - bucket name is reserved for MinIO, usually
 // returned for 'minio', '.minio.sys', buckets with capital letters.
 var errInvalidBucketName = errors.New("The specified bucket is not valid")