ad_sfs_fcntl.c

MPICH是MPI的重要研究,提供了一系列的接口函数,为并行计算的实现提供了编程环境.

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/* 
 *   $Id: ad_sfs_fcntl.c,v 1.6 2002/10/24 17:01:01 gropp Exp $    
 *
 *   Copyright (C) 1997 University of Chicago. 
 *   See COPYRIGHT notice in top-level directory.
 */

#include "ad_sfs.h"
#include "adio_extern.h"

void ADIOI_SFS_Fcntl(ADIO_File fd, int flag, ADIO_Fcntl_t *fcntl_struct, int *error_code)
{
    MPI_Datatype copy_etype, copy_filetype;
    int combiner, i, j, k, filetype_is_contig, ntimes, err, len;
    ADIOI_Flatlist_node *flat_file;
    ADIO_Offset curr_fsize, alloc_size, size, done;
    ADIO_Status status;
    char *buf;
#ifndef PRINT_ERR_MSG
    static char myname[] = "ADIOI_SFS_FCNTL";
#endif

    switch(flag) {
    case ADIO_FCNTL_SET_VIEW:
        /* free copies of old etypes and filetypes and delete flattened 
           version of filetype if necessary */

	MPI_Type_get_envelope(fd->etype, &i, &j, &k, &combiner);
	if (combiner != MPI_COMBINER_NAMED) MPI_Type_free(&(fd->etype));

	ADIOI_Datatype_iscontig(fd->filetype, &filetype_is_contig);
	if (!filetype_is_contig) ADIOI_Delete_flattened(fd->filetype);

	MPI_Type_get_envelope(fd->filetype, &i, &j, &k, &combiner);
	if (combiner != MPI_COMBINER_NAMED) MPI_Type_free(&(fd->filetype));

	/* set new info */
	ADIO_SetInfo(fd, fcntl_struct->info, &err);

        /* set new etypes and filetypes */

	MPI_Type_get_envelope(fcntl_struct->etype, &i, &j, &k, &combiner);
	if (combiner == MPI_COMBINER_NAMED) fd->etype = fcntl_struct->etype;
	else {
	    MPI_Type_contiguous(1, fcntl_struct->etype, &copy_etype);
	    MPI_Type_commit(&copy_etype);
	    fd->etype = copy_etype;
	}
	MPI_Type_get_envelope(fcntl_struct->filetype, &i, &j, &k, &combiner);
	if (combiner == MPI_COMBINER_NAMED) 
	    fd->filetype = fcntl_struct->filetype;
	else {
	    MPI_Type_contiguous(1, fcntl_struct->filetype, &copy_filetype);
	    MPI_Type_commit(&copy_filetype);
	    fd->filetype = copy_filetype;
	    ADIOI_Flatten_datatype(fd->filetype);
            /* this function will not flatten the filetype if it turns out
               to be all contiguous. */
	}

	MPI_Type_size(fd->etype, &(fd->etype_size));
	fd->disp = fcntl_struct->disp;

        /* reset MPI-IO file pointer to point to the first byte that can
           be accessed in this view. */

        ADIOI_Datatype_iscontig(fd->filetype, &filetype_is_contig);
	if (filetype_is_contig) fd->fp_ind = fcntl_struct->disp;
	else {
	    flat_file = ADIOI_Flatlist;
	    while (flat_file->type != fd->filetype) 
		flat_file = flat_file->next;
	    for (i=0; i<flat_file->count; i++) {
		if (flat_file->blocklens[i]) {
		    fd->fp_ind = fcntl_struct->disp + flat_file->indices[i];
		    break;
		}
	    }
	}
	*error_code = MPI_SUCCESS;
	break;

    case ADIO_FCNTL_GET_FSIZE:
        /* On SFS, I find that a write from one process, which changes
           the file size, does not automatically make the new file size 
           visible to other processes. Therefore, a sync-barrier-sync is 
           needed. (Other processes are able to read the data written 
           though; only file size is returned incorrectly.) */

	fsync(fd->fd_sys);
	MPI_Barrier(fd->comm);
	fsync(fd->fd_sys);
	
	fcntl_struct->fsize = llseek(fd->fd_sys, 0, SEEK_END);
	if (fd->fp_sys_posn != -1) 
	     llseek(fd->fd_sys, fd->fp_sys_posn, SEEK_SET);
#ifdef PRINT_ERR_MSG
	*error_code = (fcntl_struct->fsize == -1) ? MPI_ERR_UNKNOWN : MPI_SUCCESS;
#else
	if (fcntl_struct->fsize == -1) {
	    *error_code = MPIR_Err_setmsg(MPI_ERR_IO, MPIR_ADIO_ERROR,
			      myname, "I/O Error", "%s", strerror(errno));
	    ADIOI_Error(fd, *error_code, myname);	    
	}
	else *error_code = MPI_SUCCESS;
#endif
	break;

    case ADIO_FCNTL_SET_DISKSPACE:
	/* will be called by one process only */
        
	/* Explicitly write to allocate space. Since there could be
	   holes in the file, I need to read up to the current file
	   size, write it back, and then write beyond that depending
	   on how much preallocation is needed.
           read/write in sizes of no more than ADIOI_PREALLOC_BUFSZ */

	curr_fsize = llseek(fd->fd_sys, 0, SEEK_END);
	alloc_size = fcntl_struct->diskspace;

	size = ADIOI_MIN(curr_fsize, alloc_size);
	    
	ntimes = (int) ((size + ADIOI_PREALLOC_BUFSZ - 1)/ADIOI_PREALLOC_BUFSZ);
	buf = (char *) ADIOI_Malloc(ADIOI_PREALLOC_BUFSZ);
	done = 0;

	for (i=0; i<ntimes; i++) {
	    len = (int) (ADIOI_MIN(size-done, ADIOI_PREALLOC_BUFSZ));
	    ADIO_ReadContig(fd, buf, len, MPI_BYTE, ADIO_EXPLICIT_OFFSET, done,
			    &status, error_code);
	    if (*error_code != MPI_SUCCESS) {
#ifdef PRINT_ERR_MSG
		FPRINTF(stderr, "ADIOI_SFS_Fcntl: To preallocate disk space, ROMIO needs to read the file and write it back, but is unable to read the file. Please give the file read permission and open it with MPI_MODE_RDWR.\n");
		MPI_Abort(MPI_COMM_WORLD, 1);
#else
		*error_code = MPIR_Err_setmsg(MPI_ERR_IO, MPIR_PREALLOC_PERM,
			      myname, (char *) 0, (char *) 0);
		ADIOI_Error(fd, *error_code, myname);
                return;  
#endif
	    }
	    ADIO_WriteContig(fd, buf, len, MPI_BYTE, ADIO_EXPLICIT_OFFSET, done,
			     &status, error_code);
	    if (*error_code != MPI_SUCCESS) return;
	    done += len;
	}

	if (alloc_size > curr_fsize) {
	    memset(buf, 0, ADIOI_PREALLOC_BUFSZ); 
	    size = alloc_size - curr_fsize;
	    ntimes = (int)((size + ADIOI_PREALLOC_BUFSZ - 1)/ADIOI_PREALLOC_BUFSZ);
	    for (i=0; i<ntimes; i++) {
		len = (int) (ADIOI_MIN(alloc_size-done, ADIOI_PREALLOC_BUFSZ));
		ADIO_WriteContig(fd, buf, len, MPI_BYTE, ADIO_EXPLICIT_OFFSET, 
				 done, &status, error_code);
		if (*error_code != MPI_SUCCESS) return;
		done += len;  
	    }
	}
	ADIOI_Free(buf);

	if (fd->fp_sys_posn != -1) 
	    llseek(fd->fd_sys, fd->fp_sys_posn, SEEK_SET);

	*error_code = MPI_SUCCESS;
	break;

    case ADIO_FCNTL_SET_IOMODE:
        /* for implementing PFS I/O modes. will not occur in MPI-IO
           implementation.*/
	if (fd->iomode != fcntl_struct->iomode) {
	    fd->iomode = fcntl_struct->iomode;
	    MPI_Barrier(MPI_COMM_WORLD);
	}
	*error_code = MPI_SUCCESS;
	break;

    case ADIO_FCNTL_SET_ATOMICITY:
	fd->atomicity = (fcntl_struct->atomicity == 0) ? 0 : 1;
	*error_code = MPI_SUCCESS;
	break;

    default:
	FPRINTF(stderr, "Unknown flag passed to ADIOI_SFS_Fcntl\n");
	MPI_Abort(MPI_COMM_WORLD, 1);
    }
}