132 строки
4.6 KiB
C
132 строки
4.6 KiB
C
/*
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* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
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* University Research and Technology
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* Corporation. All rights reserved.
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* Copyright (c) 2004-2005 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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* University of Stuttgart. All rights reserved.
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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* Copyright (c) 2013-2015 University of Houston. All rights reserved.
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* $COPYRIGHT$
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*
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* Additional copyrights may follow
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*
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* $HEADER$
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*/
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#include "ompi_config.h"
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#include "sharedfp_lockedfile.h"
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#include "mpi.h"
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#include "ompi/constants.h"
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#include "ompi/mca/sharedfp/sharedfp.h"
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#include "ompi/mca/sharedfp/base/base.h"
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/*Use fcntl to lock the hidden file which stores the current position*/
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#include <fcntl.h>
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#include <unistd.h>
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int mca_sharedfp_lockedfile_request_position(struct mca_sharedfp_base_data_t * sh,
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int bytes_requested,
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OMPI_MPI_OFFSET_TYPE *offset)
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{
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int ret = OMPI_SUCCESS;
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/*file descriptor for the hidden file that we want to lock*/
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int fd;
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/* flock structure that is used to setup the desired fcntl operation */
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struct flock fl;
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OMPI_MPI_OFFSET_TYPE position = 0;
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/*buffer to use when reading from the locked file*/
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OMPI_MPI_OFFSET_TYPE buf;
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/*int count = 1;*/
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struct mca_sharedfp_lockedfile_data * lockedfile_data = sh->selected_module_data;
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int handle = lockedfile_data->handle;
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*offset = 0;
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/* get the saved file descriptor,
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* the hidden file was opened during sharedfp_lockedfile_file_open function */
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fd = handle;
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/*set up the flock structure*/
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fl.l_type = F_WRLCK;
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fl.l_whence = SEEK_SET;
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fl.l_start = 0;
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fl.l_len = 0;
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fl.l_pid = getpid();
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/* Aquire an exclusive lock */
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if (fcntl(fd, F_SETLKW, &fl) == -1) {
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opal_output(0,"sharedfp_lockedfile_request_position: errorr acquiring lock: fcntl(%d,F_SETLKW,&fl)\n",fd);
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opal_output(0,"sharedfp_lockedfile_request_position: error(%i): %s", errno, strerror(errno));
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return OMPI_ERROR;
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}
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else{
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if ( mca_sharedfp_lockedfile_verbose ) {
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opal_output(ompi_sharedfp_base_framework.framework_output,
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"sharedfp_lockedfile_request_position: Success: acquired lock.for fd: %d\n",fd);
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}
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}
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/* read from the file */
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lseek ( fd, 0, SEEK_SET );
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read ( fd, &buf, sizeof(OMPI_MPI_OFFSET_TYPE));
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if ( mca_sharedfp_lockedfile_verbose ) {
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opal_output(ompi_sharedfp_base_framework.framework_output,
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"sharedfp_lockedfile_request_position: Read last_offset=%lld! ret=%d\n",buf, ret);
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}
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/* increment the position */
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position = buf + bytes_requested;
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if ( mca_sharedfp_lockedfile_verbose ) {
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opal_output(ompi_sharedfp_base_framework.framework_output,
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"sharedfp_lockedfile_request_position: old_offset=%lld, bytes_requested=%d, new offset=%lld!\n",
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buf,bytes_requested,position);
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}
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/* write to the file */
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lseek ( fd, 0, SEEK_SET );
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write ( fd, &position, sizeof(OMPI_MPI_OFFSET_TYPE));
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/* unlock the file */
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if ( mca_sharedfp_lockedfile_verbose ) {
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opal_output(ompi_sharedfp_base_framework.framework_output,
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"sharedfp_lockedfile_request_position: Releasing lock...");
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}
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/* NOTE: We thought we could reuse the flock struct
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** and only reset the l_type parameter, but it gave
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** an invalid argument error. On my machine the invalid
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** argument was l_whence. I reset it, but I also decided to
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** reset all of the other parameters to avoid further problems.
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*/
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fl.l_type = F_UNLCK; /* set to unlock same region */
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fl.l_whence = SEEK_SET;
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fl.l_start = 0;
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fl.l_len = 0;
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fl.l_pid = getpid();
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if (fcntl(fd, F_SETLK, &fl) == -1) {
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opal_output(0,"sharedfp_lockedfile_request_position:failed to release lock for fd: %d\n",fd);
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opal_output(0,"error(%i): %s", errno, strerror(errno));
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return OMPI_ERROR;
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}
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else {
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if ( mca_sharedfp_lockedfile_verbose ) {
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opal_output(ompi_sharedfp_base_framework.framework_output,
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"sharedfp_lockedfile_request_position: released lock.for fd: %d\n",fd);
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}
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}
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/* return position */
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*offset = buf;
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return ret;
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}
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