common_ompio_file_set_view: fix handling of MPI_DISPLACEMENT_CURRENT

If MPI_MODE_SEQUENTIAL was used when opening the file, the special displacement  MPI_DISPLACEMENT_CURRENT
has to be used during file_set_view. The displacement is set to the current position of the shared file pointer
in this case. It is illegal to use MPI_DISPLACEMENT_CURRENT unless amode MPI_MODE_SEQUENTIAL was used.

Signed-off-by: Edgar Gabriel <egabriel@central.uh.edu>

Author: edgargabriel

ompi/mca/common/ompio/common_ompio_file_view.c

@@ -9,7 +9,7 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
- * Copyright (c) 2008-2019 University of Houston. All rights reserved.
+ * Copyright (c) 2008-2021 University of Houston. All rights reserved.
  * Copyright (c) 2017-2018 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * Copyright (c) 2017      IBM Corporation. All rights reserved.
@@ -72,6 +72,16 @@ int mca_common_ompio_set_view (ompio_file_t *fh,
     ptrdiff_t ftype_extent, lb, ub;
     ompi_datatype_t *newfiletype;
 
+    if ( (MPI_DISPLACEMENT_CURRENT == disp) &&
+         (fh->f_amode & MPI_MODE_SEQUENTIAL) ) {
+        mca_sharedfp_base_module_t * shared_fp_base_module = fh->f_sharedfp;
+        if ( NULL == shared_fp_base_module ){
+            opal_output(0, "No shared file pointer component found for this file. Can not execute\n");
+            return OMPI_ERROR;
+        }
+        shared_fp_base_module->sharedfp_get_position(fh, &disp);
+    }
+    
     if ( NULL != fh->f_etype ) {
         ompi_datatype_destroy (&fh->f_etype);
     }

ompi/mca/io/ompio/io_ompio_file_set_view.c

@@ -77,7 +77,14 @@ int mca_io_ompio_file_set_view (ompi_file_t *fp,
        file pointer, once for the shared file pointer (if it is existent)
     */
     fh = &data->ompio_fh;
-  
+
+    if ( MPI_DISPLACEMENT_CURRENT == disp &&
+         !(fh->f_amode & MPI_MODE_SEQUENTIAL ) ) {
+        // MPI_DISPLACEMENT_CURRENT is only valid if amode is MPI_MODE_SEQUENTIAL
+        return MPI_ERR_DISP;
+    }
+        
+    
     OPAL_THREAD_LOCK(&fp->f_lock);
     ret = mca_common_ompio_set_view(fh, disp, etype, filetype, datarep, info);
     OPAL_THREAD_UNLOCK(&fp->f_lock);