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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
*
* Copyright (C) 2007 UChicago/Argonne LLC
* See COPYRIGHT notice in top-level directory.
*/
#include "adio.h"
/* this "collective" open is useful for frankly broken file systems such
* as NFS where a create from one client might not be immediately
* visible on another */
void ADIOI_FAILSAFE_OpenColl(ADIO_File fd, int rank,
int access_mode, int *error_code)
{
int orig_amode_excl, orig_amode_wronly;
orig_amode_excl = access_mode;
if ((access_mode & ADIO_CREATE) && (access_mode & ADIO_EXCL)) {
/* the open should fail if the file exists. Only *1* process
* should check this. Otherwise, if all processes try to check
* and the file does not exist, one process will create the file
* and others who reach later will return error. */
if(rank == fd->hints->ranklist[0]) {
fd->access_mode = access_mode;
(*(fd->fns->ADIOI_xxx_Open))(fd, error_code);
MPI_Bcast(error_code, 1, MPI_INT, \
fd->hints->ranklist[0], fd->comm);
/* if no error, close the file and reopen normally below */
if (*error_code == MPI_SUCCESS)
(*(fd->fns->ADIOI_xxx_Close))(fd, error_code);
}
else MPI_Bcast(error_code, 1, MPI_INT,
fd->hints->ranklist[0], fd->comm);
if (*error_code != MPI_SUCCESS) {
return;
}
else {
/* turn off EXCL for real open */
access_mode = access_mode ^ ADIO_EXCL;
}
}
/* if we are doing deferred open, non-aggregators should return now */
if (fd->hints->deferred_open && !(fd->is_agg)) {
/* we might have turned off EXCL for the aggregators.
* restore access_mode that non-aggregators get the right
* value from get_amode */
fd->access_mode = orig_amode_excl;
*error_code = MPI_SUCCESS;
return;
}
/* For writing with data sieving, a read-modify-write is needed. If
the file is opened for write_only, the read will fail. Therefore,
if write_only, open the file as read_write, but record it as write_only
in fd, so that get_amode returns the right answer. */
orig_amode_wronly = access_mode;
if (access_mode & ADIO_WRONLY) {
access_mode = access_mode ^ ADIO_WRONLY;
access_mode = access_mode | ADIO_RDWR;
}
fd->access_mode = access_mode;
(*(fd->fns->ADIOI_xxx_Open))(fd, error_code);
/* if error, may be it was due to the change in amode above.
therefore, reopen with access mode provided by the user.*/
fd->access_mode = orig_amode_wronly;
if (*error_code != MPI_SUCCESS)
(*(fd->fns->ADIOI_xxx_Open))(fd, error_code);
if(*error_code != MPI_SUCCESS) return;
/* if we turned off EXCL earlier, then we should turn it back on */
if (fd->access_mode != orig_amode_excl) fd->access_mode = orig_amode_excl;
/* for deferred open: this process has opened the file (because if we are
* not an aggregaor and we are doing deferred open, we returned earlier)*/
fd->is_open = 1;
}
/*
* vim: ts=8 sts=4 sw=4 noexpandtab
*/
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