Merge pull request open-mpi#5022 from edgargabriel/pr/v3.0.x-sequential-mode-fix

io/ompio: don't reset amode if MODE_SEQUENTIAL is set

Author: bwbarrett

ompi/mca/common/ompio/common_ompio_file_open.c

@@ -111,10 +111,12 @@ int mca_common_ompio_file_open (ompi_communicator_t *comm,
 
     /* This fix is needed for data seiving to work with
        two-phase collective I/O */
-     if ((amode & MPI_MODE_WRONLY)){
-       amode -= MPI_MODE_WRONLY;
-       amode += MPI_MODE_RDWR;
-     }
+    if ( !(amode & MPI_MODE_SEQUENTIAL) ) {
+        if ((amode & MPI_MODE_WRONLY)){
+            amode -= MPI_MODE_WRONLY;
+            amode += MPI_MODE_RDWR;
+        }
+    }
      /*--------------------------------------------------*/