make arbitrary sequences of explicit and implicit offset operations work properly.

This commit was SVN r32537.

ompi/mca/io/ompio/io_ompio_file_open.c

@@ -634,15 +634,26 @@ mca_io_ompio_file_seek (ompi_file_t *fh,
 }
 
 int
-mca_io_ompio_file_get_position (ompi_file_t *fh,
+mca_io_ompio_file_get_position (ompi_file_t *fd,
                                 OMPI_MPI_OFFSET_TYPE *offset)
 {
-    mca_io_ompio_data_t *data;
+    mca_io_ompio_data_t *data=NULL;
+    mca_io_ompio_file_t *fh=NULL;
+    OMPI_MPI_OFFSET_TYPE off;
 
-    data = (mca_io_ompio_data_t *) fh->f_io_selected_data;
+    data = (mca_io_ompio_data_t *) fd->f_io_selected_data;
+    fh = &data->ompio_fh;
 
-    *offset = data->ompio_fh.f_position_in_file_view / data->ompio_fh.f_etype_size;
+    /* No of copies of the entire file view */
+    off = (fh->f_offset - fh->f_disp)/fh->f_view_extent;
 
+    /* No of elements per view */
+    off *= (fh->f_view_size / fh->f_etype_size);
+
+    /* No of bytes used in the current copy of the view */
+    off += fh->f_total_bytes / fh->f_etype_size;
+
+    *offset = off;
     return OMPI_SUCCESS;
 }
 

ompi/mca/io/ompio/io_ompio_file_read.c

@@ -172,6 +172,9 @@ int ompio_io_ompio_file_read_at (mca_io_ompio_file_t *fh,
 				 ompi_status_public_t * status)
 {
     int ret = OMPI_SUCCESS;
+    OMPI_MPI_OFFSET_TYPE prev_offset;
+    
+    mca_io_ompio_file_get_position (fh->f_fh, &prev_offset );
 
     ompi_io_ompio_set_explicit_offset (fh, offset);
     ret = ompio_io_ompio_file_read (fh,
@@ -179,6 +182,12 @@ int ompio_io_ompio_file_read_at (mca_io_ompio_file_t *fh,
 				    count,
 				    datatype,
 				    status);
+
+    // An explicit offset file operation is not suppsed to modify
+    // the internal file pointer. So reset the pointer
+    // to the previous value
+    ompi_io_ompio_set_explicit_offset (fh, prev_offset);
+
     return ret;
 }
 
@@ -298,6 +307,9 @@ int ompio_io_ompio_file_iread_at (mca_io_ompio_file_t *fh,
 				  ompi_request_t **request)
 {
     int ret = OMPI_SUCCESS;
+    OMPI_MPI_OFFSET_TYPE prev_offset;
+    
+    mca_io_ompio_file_get_position (fh->f_fh, &prev_offset );
 
     ompi_io_ompio_set_explicit_offset (fh, offset);
     ret = ompio_io_ompio_file_iread (fh,
@@ -305,6 +317,17 @@ int ompio_io_ompio_file_iread_at (mca_io_ompio_file_t *fh,
 				    count,
 				    datatype,
 				    request);
+
+    /* An explicit offset file operation is not suppsed to modify
+    ** the internal file pointer. So reset the pointer
+    ** to the previous value
+    ** It is OK to reset the position already here, althgouth 
+    ** the operation might still be pending/ongoing, since
+    ** the entire array of <offset, length, memaddress> have 
+    ** already been constructed in the file_iread operation
+    */
+    ompi_io_ompio_set_explicit_offset (fh, prev_offset);
+
     return ret;
 }
 

ompi/mca/io/ompio/io_ompio_file_write.c

@@ -168,6 +168,8 @@ int ompio_io_ompio_file_write_at (mca_io_ompio_file_t *fh,
 				  ompi_status_public_t *status)
 {
     int ret = OMPI_SUCCESS;
+    OMPI_MPI_OFFSET_TYPE prev_offset;
+    mca_io_ompio_file_get_position (fh->f_fh, &prev_offset );
 
     ompi_io_ompio_set_explicit_offset (fh, offset);
     ret = ompio_io_ompio_file_write (fh,
@@ -175,7 +177,10 @@ int ompio_io_ompio_file_write_at (mca_io_ompio_file_t *fh,
                                      count,
                                      datatype,
                                      status);
-
+    // An explicit offset file operation is not suppsed to modify
+    // the internal file pointer. So reset the pointer
+    // to the previous value
+    ompi_io_ompio_set_explicit_offset (fh, prev_offset );
     return ret;
 }
 
@@ -291,6 +296,8 @@ int ompio_io_ompio_file_iwrite_at (mca_io_ompio_file_t *fh,
 				   ompi_request_t **request)
 {
     int ret = OMPI_SUCCESS;
+    OMPI_MPI_OFFSET_TYPE prev_offset;
+    mca_io_ompio_file_get_position (fh->f_fh, &prev_offset );
 
     ompi_io_ompio_set_explicit_offset (fh, offset);
     ret = ompio_io_ompio_file_iwrite (fh,
@@ -298,6 +305,17 @@ int ompio_io_ompio_file_iwrite_at (mca_io_ompio_file_t *fh,
                                     count,
                                     datatype,
                                     request);
+
+    /* An explicit offset file operation is not suppsed to modify
+    ** the internal file pointer. So reset the pointer
+    ** to the previous value
+    ** It is OK to reset the position already here, althgouth 
+    ** the operation might still be pending/ongoing, since
+    ** the entire array of <offset, length, memaddress> have 
+    ** already been constructed in the file_iwrite operation
+    */
+    ompi_io_ompio_set_explicit_offset (fh, prev_offset);
+
     return ret;
 }