path: root/test/vfd_swmr.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/***********************************************************
*
* Test program:	 
*
* Tests the VFD SWMR Feature.
*
*************************************************************/

#include "bsdqueue.h"
#include "h5test.h"

/*
 * This file needs to access private information from the H5F package.
 */

#define H5F_FRIEND		    /*suppress error about including H5Fpkg */
#define H5FD_FRIEND		    /*suppress error about including H5FDpkg */
#define H5F_TESTING
#define H5FD_TESTING
#include "H5FDprivate.h"
#include "H5Fpkg.h"
#include "H5FDpkg.h"
#include "H5Iprivate.h"

#define H5FD_FRIEND       /*suppress error about including H5FDpkg      */
#define H5FD_TESTING
#include "H5FDpkg.h"

#define FS_PAGE_SIZE    512
#define FILENAME        "vfd_swmr_file.h5"
#define MD_FILENAME     "vfd_swmr_metadata_file"

#define FILENAME2        "vfd_swmr_file2.h5"
#define MD_FILENAME2     "vfd_swmr_metadata_file2"

#define FNAME            "non_vfd_swmr_file.h5"

/* test routines for VFD SWMR */
static unsigned test_fapl(void);
static unsigned test_file_end_tick(void);
static unsigned test_file_fapl(void);
static unsigned test_writer_md(void);


/*-------------------------------------------------------------------------
 * Function:    test_fapl()
 *
 * Purpose:     A) Verify that invalid info set in the fapl fails
 *                 as expected (see the RFC for VFD SWMR):
 *                 --version: should be a known version
 *                 --tick_len: should be >= 0
 *                 --max_lag: should be >= 3
 *                 --md_pages_reserved: should be >= 2
 *                 --md_file_path: should contain the metadata file path (POSIX)
 *              B) Verify that info set in the fapl is retrieved correctly.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; July 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_fapl(void)
{
    hid_t fapl = -1;    /* File access property list */
    H5F_vfd_swmr_config_t *my_config = NULL;   /* Configuration for VFD SWMR */
    herr_t ret;         /* Return value */

    TESTING("Configure VFD SWMR with fapl");

    /* Allocate memory for the configuration structure */
    if((my_config = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    HDmemset(my_config, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Get a copy of the file access property list */
    if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Should get invalid VFD SWMR config info */
    if(H5Pget_vfd_swmr_config(fapl, my_config) < 0)
        TEST_ERROR;

    /* Verify that the version is incorrect */
    if(my_config->version >= H5F__CURR_VFD_SWMR_CONFIG_VERSION)
        TEST_ERROR;

    /* Should fail: version is 0 */
    H5E_BEGIN_TRY {
        ret = H5Pset_vfd_swmr_config(fapl, my_config);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Set valid version */
    my_config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;

    /* Set valid tick_len */
    my_config->tick_len = 3; 
    /* Should fail: max_lag is 2 */
    my_config->max_lag = 2;
    H5E_BEGIN_TRY {
        ret = H5Pset_vfd_swmr_config(fapl, my_config);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Set valid max_lag */
    my_config->max_lag = 3;
    /* Should fail: md_pages_reserved is 0 */
    H5E_BEGIN_TRY {
        ret = H5Pset_vfd_swmr_config(fapl, my_config);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Set valid md_pages_reserved */
    my_config->md_pages_reserved = 2;
    /* Should fail: empty md_file_path */
    H5E_BEGIN_TRY {
        ret = H5Pset_vfd_swmr_config(fapl, my_config);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Set md_file_path */
    HDstrcpy(my_config->md_file_path, MD_FILENAME);
    my_config->writer = TRUE;

    /* Should succeed in setting the configuration info */
    if(H5Pset_vfd_swmr_config(fapl, my_config) < 0)
        TEST_ERROR;

    /* Clear the configuration structure */
    HDmemset(my_config, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Retrieve the configuration info just set */
    if(H5Pget_vfd_swmr_config(fapl, my_config) < 0)
        TEST_ERROR;

    /* Verify the configuration info */
    if(my_config->version < H5F__CURR_VFD_SWMR_CONFIG_VERSION)
        TEST_ERROR;
    if(my_config->md_pages_reserved != 2)
        TEST_ERROR;
    if(HDstrcmp(my_config->md_file_path, MD_FILENAME) != 0)
        TEST_ERROR;

    /* Close the file access property list */
    if(H5Pclose(fapl) < 0)
        FAIL_STACK_ERROR;

    if(my_config)
        HDfree(my_config);

    PASSED();
    return 0;

error:
    H5E_BEGIN_TRY {
        H5Pclose(fapl);
    } H5E_END_TRY;
    if(my_config)
        HDfree(my_config);
    return 1;
} /* test_fapl() */


/*-------------------------------------------------------------------------
 * Function:    test_file_fapl()
 *
 * Purpose:     A) Verify that page buffering and paged aggregation
 *                 have to be enabled for a file to be configured
 *                 with VFD SWMR.
 *              B) Verify that the "writer" setting in the fapl's VFD
 *                 SWMR configuration should be consistent with the
 *                 file access flags.
 *              C) Verify the VFD SWMR configuration set in fapl
 *                 used to create/open the file is the same as the
 *                 configuration retrieved from the file's fapl.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; July 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_file_fapl(void)
{
    hid_t fid = -1;         /* File ID */
    hid_t fid2 = -1;        /* File ID */
    hid_t fcpl = -1;        /* File creation property list ID */
    hid_t fapl1 = -1;       /* File access property list ID */
    hid_t fapl2 = -1;       /* File access property list ID */
    hid_t file_fapl = -1;   /* File access property list ID associated with the file */
    H5F_vfd_swmr_config_t *config1 = NULL;      /* Configuration for VFD SWMR */
    H5F_vfd_swmr_config_t *config2 = NULL;      /* Configuration for VFD SWMR */
    H5F_vfd_swmr_config_t *file_config = NULL;  /* Configuration for VFD SWMR */

    TESTING("VFD SWMR configuration for the file and fapl");

    /* Should succeed without VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Close the file  */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Allocate memory for the configuration structure */
    if((config1 = (H5F_vfd_swmr_config_t *)HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    if((config2 = (H5F_vfd_swmr_config_t *)HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    if((file_config = (H5F_vfd_swmr_config_t *)HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Configured as VFD SWMR reader */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 6;
    config1->writer = FALSE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Should fail to create: file access is writer but VFD SWMR config is reader */
    H5E_BEGIN_TRY {
        fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl1);
    } H5E_END_TRY;
    if(fid >= 0)
        TEST_ERROR;

    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Configured as VFD SWMR writer */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 6;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Should fail to create: page buffering and paged aggregation not enabled */
    H5E_BEGIN_TRY {
        fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, fapl1);
    } H5E_END_TRY;
    if(fid >= 0)
        TEST_ERROR;


    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
            FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    /* Should fail to create: no page buffering */
    H5E_BEGIN_TRY {
        fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl1);
    } H5E_END_TRY;
    if(fid >= 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Should succeed to create the file: paged aggregation and page buffering enabled */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl1)) < 0)
        TEST_ERROR;

    /* Get the file's file access property list */
    if((file_fapl = H5Fget_access_plist(fid)) < 0)
        FAIL_STACK_ERROR;

    /* Retrieve the VFD SWMR configuration from file_fapl */
    if(H5Pget_vfd_swmr_config(file_fapl, file_config) < 0)
        TEST_ERROR;

    /* Verify the retrieved info is the same as config1 */
    if(HDmemcmp(config1, file_config, sizeof(H5F_vfd_swmr_config_t)) != 0)
        TEST_ERROR;

    /* Closing */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(file_fapl) < 0)
        FAIL_STACK_ERROR;

    /* Should fail to open: file access is reader but VFD SWMR config is writer */
    H5E_BEGIN_TRY {
        fid = H5Fopen(FILENAME, H5F_ACC_RDONLY, fapl1);
    } H5E_END_TRY;
    if(fid >= 0)
        TEST_ERROR;

    /* Should succeed to open: file access and VFD SWMR config are consistent */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1)) < 0)
        TEST_ERROR;

    /* Get the file's file access property list */
    if((file_fapl = H5Fget_access_plist(fid)) < 0)
        FAIL_STACK_ERROR;

    /* Clear info in file_config */
    HDmemset(file_config, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Retrieve the VFD SWMR configuration from file_fapl */
    if(H5Pget_vfd_swmr_config(file_fapl, file_config) < 0)
        TEST_ERROR;

    /* Verify the retrieved info is the same as config1 */
    if(HDmemcmp(config1, file_config, sizeof(H5F_vfd_swmr_config_t)) != 0)
        TEST_ERROR;

    /* Closing */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(file_fapl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl2 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up different VFD SWMR configuration */
    config2->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config2->tick_len = 4; 
    config2->max_lag = 10;
    config2->writer = TRUE;
    config2->md_pages_reserved = 2;
    HDstrcpy(config2->md_file_path, MD_FILENAME);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl2, config2) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl2, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Should succeed to open the file as VFD SWMR writer */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl2)) < 0)
        TEST_ERROR;

    /* Get the file's file access property list */
    if((file_fapl = H5Fget_access_plist(fid)) < 0)
        FAIL_STACK_ERROR;

    /* Clear info in file_config */
    HDmemset(file_config, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Retrieve the VFD SWMR configuration from file_fapl */
    if(H5Pget_vfd_swmr_config(file_fapl, file_config) < 0)
        TEST_ERROR;

    /* Verify the retrieved info is NOT the same as config1 */
    if(HDmemcmp(config1, file_config, sizeof(H5F_vfd_swmr_config_t)) == 0)
        TEST_ERROR;

    /* Verify the retrieved info is the same as config2 */
    if(HDmemcmp(config2, file_config, sizeof(H5F_vfd_swmr_config_t)) != 0)
        TEST_ERROR;

    /* The file previously opened as VDF SWMR writer is still open */
    /* with VFD SWMR configuration in config2 */

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR writer in config1 but different from config2 */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 3; 
    config1->max_lag = 8;
    config1->writer = TRUE;
    config1->md_pages_reserved = 3;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Re-open the same file with config1 */
    /* Should fail to open since config1 is different from config2 setting */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    /* Close fapl1 */
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR reader in config1 with is same as config2 */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 10;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Re-open the same file as VFD SWMR writer */
    /* Should succeed since config1 is same as the setting in config2 */
    if((fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1)) < 0)
        TEST_ERROR

    /* Close fapl1 */
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;

    HDmemset(file_config, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Get the file's file access property list */
    if((file_fapl = H5Fget_access_plist(fid)) < 0)
        FAIL_STACK_ERROR;

    /* Retrieve the VFD SWMR configuration from file_fapl */
    if(H5Pget_vfd_swmr_config(file_fapl, file_config) < 0)
        TEST_ERROR;

    /* Should be the same as config1 */
    if(HDmemcmp(config1, file_config, sizeof(H5F_vfd_swmr_config_t)) != 0)
        TEST_ERROR;

    /* Should be the the same as config2 */
    if(HDmemcmp(config2, file_config, sizeof(H5F_vfd_swmr_config_t)) != 0)
        TEST_ERROR;

    /* Closing */
    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;
    if(H5Fclose(fid) < 0)

    /* Closing */
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl2) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(file_fapl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    /* Free buffers */
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);
    if(file_config)
        HDfree(file_config);

    PASSED();
    return 0;

error:
    H5E_BEGIN_TRY {
        H5Pclose(fapl1);
        H5Pclose(fapl2);
        H5Pclose(file_fapl);
        H5Pclose(fcpl);
        H5Fclose(fid);
    } H5E_END_TRY;
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);
    if(file_config)
        HDfree(file_config);
    return 1;
} /* test_file_fapl() */


/*-------------------------------------------------------------------------
 * Function:    test_file_end_tick()
 *
 * Purpose:     Verify the public routine H5Fvfd_swmr_end_tick() works
 *              as described in the RFC for VFD SWMR.
 *              --routine will fail if the file is not opened with VFD SWMR
 *              ?? Will add more tests when end of tick processing 
 *                 is activated in this routine
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; July 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_file_end_tick(void)
{
    hid_t fid = -1;     /* File ID */
    hid_t fapl = -1;    /* File access property list */
    hid_t fcpl = -1;    /* File creation property list */
    H5F_vfd_swmr_config_t *my_config = NULL;    /* Configuration for VFD SWMR */
    herr_t ret;         /* Return value */

    TESTING("H5Fvfd_swmr_end_tick() for VFD SWMR");

    /* Should succeed without VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Should fail */
    H5E_BEGIN_TRY {
        ret = H5Fvfd_swmr_end_tick(fid);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Close the file  */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Allocate memory for the configuration structure */
    if((my_config = (H5F_vfd_swmr_config_t *)HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR;
    
    /* Set the configuration */
    my_config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    my_config->tick_len = 3; 
    my_config->max_lag = 3;
    my_config->writer = TRUE;
    my_config->md_pages_reserved = 2;
    HDstrcpy(my_config->md_file_path, MD_FILENAME);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl, my_config) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    /* Create the file with VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Should succeed */
    if(H5Fvfd_swmr_end_tick(fid) < 0)
        TEST_ERROR;

    /* Close the file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Open the file as VFD SWMR writer */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl)) < 0)
        TEST_ERROR;

    /* Should succeed */
    if(H5Fvfd_swmr_end_tick(fid) < 0)
        TEST_ERROR;

    /* Close the file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Open the file as reader without VFD SWMR configured */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT)) < 0)
        FAIL_STACK_ERROR;

    /* Should fail */
    H5E_BEGIN_TRY {
        ret = H5Fvfd_swmr_end_tick(fid);
    } H5E_END_TRY;
    if(ret >= 0)
        TEST_ERROR;

    /* Close the file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    if(H5Pclose(fapl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;
    if(my_config)
        HDfree(my_config);

    PASSED();
    return 0;

error:
    H5E_BEGIN_TRY {
        H5Pclose(fapl);
        H5Pclose(fcpl);
        H5Fclose(fid);
    } H5E_END_TRY;

    if(my_config)
        HDfree(my_config);

    return 1;
} /* test_file_end_tick() */


/*-------------------------------------------------------------------------
 * Function:    test_writer_create_open_flush()
 *
 * Purpose:     Verify info in the metadata file when:
 *              --creating the HDF5 file
 *              --flushing the HDF5 file
 *              --opening an existing HDF5 file
 *              It will call the internal testing routine 
 *              H5F__vfd_swmr_writer_create_open_flush_test() to do the following:
 *              --Open the metadata file
 *              --Verify the file size is as expected (md_pages_reserved)
 *              --For file create:
 *                  --No header magic is found
 *              --For file open or file flush:
 *                  --Read and decode the header and index in the metadata file
 *                  --Verify info in the header and index read from
 *                    the metadata file is as expected (empty index)
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; October 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_writer_create_open_flush(void)
{
    hid_t fid = -1;     /* File ID */
    hid_t fapl = -1;    /* File access property list */
    hid_t fcpl = -1;    /* File creation property list */
    H5F_vfd_swmr_config_t *my_config = NULL;    /* Configuration for VFD SWMR */

    TESTING("Create/Open/Flush an HDF5 file for VFD SWMR");

    /* Allocate memory for the configuration structure */
    if((my_config = HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR;
    
    /* Set up the VFD SWMR configuration */
    my_config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    my_config->tick_len = 1; 
    my_config->max_lag = 3;
    my_config->writer = TRUE;
    my_config->md_pages_reserved = 2;
    HDstrcpy(my_config->md_file_path, MD_FILENAME);

    /* Set the VFD SWMR configuration in fapl */
    if(H5Pset_vfd_swmr_config(fapl, my_config) < 0)
        FAIL_STACK_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    /* Create an HDF5 file with VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Verify info in metadata file when creating the HDF5 file */
    if(H5F__vfd_swmr_writer_create_open_flush_test(fid, TRUE) < 0)
        FAIL_STACK_ERROR;

#ifdef LATER /* Will activate the test when flush is implemented */
    /* Flush the HDF5 file */
    if(H5Fflush(fid, H5F_SCOPE_GLOBAL) < 0) 
        FAIL_STACK_ERROR

    /* Verify info in metadata file when flushing the HDF5 file */
    if(H5F__vfd_swmr_writer_create_open_flush_test(fid, FALSE) < 0)
        FAIL_STACK_ERROR
#endif

    /* Close the file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Re-open the file as VFD SWMR writer */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Verify info in metadata file when reopening the HDF5 file */
    if(H5F__vfd_swmr_writer_create_open_flush_test(fid, FALSE) < 0)
        FAIL_STACK_ERROR;

    /* Closing */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    if(my_config)
        HDfree(my_config);

    PASSED();
    return 0;

error:
    if(my_config)
        HDfree(my_config);
    
    H5E_BEGIN_TRY {
        H5Pclose(fapl);
        H5Pclose(fcpl);
        H5Fclose(fid);
    } H5E_END_TRY;

    return 1;
} /* test_writer_create_open_flush() */


/*-------------------------------------------------------------------------
 * Function:    test_writer_md()
 *
 * Purpose:     Verify info in the metadata file after updating with the 
 *              constructed index: (A), (B), (C), (D)
 *              It will call the internal testing routine 
 *              H5F__vfd_swmr_writer_md_test() to do the following:
 *              --Update the metadata file with the input index via the
 *                internal library routine H5F_update_vfd_swmr_metadata_file()
 *              --Verify the entries in the delayed list is as expected: 
 *                --num_dl_entries
 *              --Open the metadata file, read and decode the header and index
 *              --Verify header and index info just read from the metadata
 *                file is as expected:
 *                --num_entries and index
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; October 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_writer_md(void)
{
    hid_t fid = -1;             /* File ID */
    hid_t fapl = -1;            /* File access property list */
    hid_t fcpl = -1;            /* File creation property list */
    unsigned num_entries = 0;   /* Number of entries in the index */
    unsigned i = 0;             /* Local index variables */
    uint8_t *buf = NULL;        /* Data page from the page buffer */
    hid_t dcpl = -1;            /* Dataset creation property list */
    hid_t sid = -1;             /* Dataspace ID */
    hid_t did = -1;             /* Dataset ID */
    int *rwbuf = NULL;          /* Data buffer for writing */
    H5O_info_t oinfo;           /* Object metadata information */
    char dname[100];            /* Name of dataset */
    hsize_t dims[2] = {50, 20}; /* Dataset dimension sizes */
    hsize_t max_dims[2] = {H5S_UNLIMITED, H5S_UNLIMITED}; /* Dataset maximum dimension sizes */
    hsize_t chunk_dims[2] = {2, 5};             /* Dataset chunked dimension sizes */
    H5FD_vfd_swmr_idx_entry_t *index = NULL;    /* Pointer to the index entries */
    H5F_vfd_swmr_config_t *my_config = NULL;    /* Configuration for VFD SWMR */

    TESTING("Verify the metadata file for VFD SWMR writer");

    /* Allocate memory for the configuration structure */
    if((my_config = HDcalloc(1, sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR;
    
    /* Set up the VFD SWMR configuration */
    my_config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    my_config->tick_len = 1; 
    my_config->max_lag = 3;
    my_config->writer = TRUE;
    my_config->md_pages_reserved = 256;
    HDstrcpy(my_config->md_file_path, MD_FILENAME);

    /* Set the VFD SWMR configuration in fapl */
    if(H5Pset_vfd_swmr_config(fapl, my_config) < 0)
        FAIL_STACK_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl, FS_PAGE_SIZE, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;
    if(H5Pset_file_space_page_size(fcpl, FS_PAGE_SIZE) < 0)
        FAIL_STACK_ERROR;

    /* Create an HDF5 file with VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl)) < 0)
        FAIL_STACK_ERROR;

    /* Allocate num_entries for the data buffer */
    num_entries = 10;
    if((buf = HDcalloc(num_entries, FS_PAGE_SIZE)) == NULL)
        FAIL_STACK_ERROR;

    /* Allocate memory for num_entries index */
    index = HDcalloc(num_entries, sizeof(H5FD_vfd_swmr_idx_entry_t));
    if(NULL == index)
        FAIL_STACK_ERROR;

    /* (A) Construct index for updating the metadata file */
    for(i = 0; i < num_entries; i++) {
        index[i].hdf5_page_offset = 3 + 7 * i;
        index[i].md_file_page_offset = 1 + (num_entries - i) * 5;
        index[i].length = (uint32_t)FS_PAGE_SIZE;
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];
    }

    /* Update with index and verify info in the metadata file */
    /* Also verify that 0 entries will be on the delayed list */
    if(H5F__vfd_swmr_writer_md_test(fid, num_entries, index, 0) < 0)
        TEST_ERROR

    /* Create dataset creation property list */
    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set to use chunked dataset */
    if(H5Pset_chunk(dcpl, 2, chunk_dims) < 0)
        FAIL_STACK_ERROR

    /* Create dataspace */
    if((sid = H5Screate_simple(2, dims, max_dims)) < 0)
        FAIL_STACK_ERROR

    /* Perform activities to ensure that max_lag ticks elapse */
    for(i = 0; i < 1000; i++) {

        /* Create a chunked dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dcreate2(fid, dname, H5T_NATIVE_INT, sid, H5P_DEFAULT, dcpl, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Get dataset object header address */
        if(H5Oget_info2(did, &oinfo, H5O_INFO_BASIC) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* (B) Update every other entry in the index */
    for(i = 0; i < num_entries; i+= 2)
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];

    /* Update with index and verify info in the metadata file */
    /* Also verify that 5 entries will be on the delayed list */
    if(H5F__vfd_swmr_writer_md_test(fid, num_entries, index, 5) < 0)
        TEST_ERROR

    /* Allocate memory for the read/write buffer */
    if((rwbuf = (int *)HDmalloc(sizeof(int) * (50 * 20))) == NULL)
        FAIL_STACK_ERROR;
    for(i = 0; i < (50 * 20); i++)
        rwbuf[i] = (int)i;

    /* Perform activities to ensure that max_lag ticks elapse */
    for(i = 0; i < 1000; i++) {
        /* Open the dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Write to the dataset */
        if(H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rwbuf) < 0)
            FAIL_STACK_ERROR

        /* Get dataset object info */
        if(H5Oget_info2(did, &oinfo, H5O_INFO_BASIC) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* (C) Update every 3 entry in the index */
    for(i = 0; i < num_entries; i+= 3)
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];

    /* Update with index and verify info in the metadata file */
    /* Also verify that 4 entries will be on the delayed list */
    if(H5F__vfd_swmr_writer_md_test(fid, num_entries, index, 4) < 0)
        TEST_ERROR

    /* Clear the read/write buffer */
    HDmemset(rwbuf, 0, sizeof(sizeof(int) * (50 * 20)));

    /* Perform activities to ensure that max_lag ticks elapse */
    for(i = 0; i < 1000; i++) {
        /* Open the dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Read from the dataset */
        if(H5Dread(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rwbuf) < 0)
            FAIL_STACK_ERROR

        /* Get dataset object info */
        if(H5Oget_info2(did, &oinfo, H5O_INFO_BASIC) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* (D) Update two entries in the index */
    index[1].entry_ptr = &buf[1 * FS_PAGE_SIZE];
    index[5].entry_ptr = &buf[5 * FS_PAGE_SIZE];

    /* Update with index and verify info in the metadata file */
    /* Also verify that 2 entries will be on the delayed list */
    if(H5F__vfd_swmr_writer_md_test(fid, num_entries, index, 2) < 0)
        TEST_ERROR

    /* Closing */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;
    if(H5Sclose(sid) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(dcpl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    /* Free resources */
    if(my_config)
        HDfree(my_config);
    if(buf)
        HDfree(buf);
    if(rwbuf)
        HDfree(rwbuf);
    if(index)
        HDfree(index);

    PASSED();
    return 0;

error:
    if(my_config)
        HDfree(my_config);
     if(buf)
        HDfree(buf);
    if(rwbuf)
        HDfree(rwbuf);
    if(index)
        HDfree(index);

    H5E_BEGIN_TRY {
        H5Dclose(did);
        H5Sclose(sid);
        H5Pclose(dcpl);
        H5Pclose(fapl);
        H5Pclose(fcpl);
        H5Fclose(fid);
    } H5E_END_TRY;

    return 1;
} /* test_writer__md() */


#if !(defined(H5_HAVE_FORK) && defined(H5_HAVE_WAITPID) && defined(H5_HAVE_FLOCK))

static unsigned
test_reader_md_concur(void)
{
    /* Output message about test being performed */
    TESTING("Verify the metadata file for VFD SWMR reader");
    SKIPPED();
    HDputs("    Test skipped due to fork, waitpid, or flock not defined.");
    return 0;

} /* end test_reader_md_concur() */

#else /* defined(H5_HAVE_FORK && defined(H5_HAVE_WAITPID) && defined(H5_HAVE_FLOCK) */

/*-------------------------------------------------------------------------
 * Function:    test_reader_md_concur()
 *
 * Purpose:     Verify metadata file info updated by the writer is 
 *              what the reader obtained from the metadata file:
 *              --Cases (A), (B), (C), (D), (E)
 *              NOTE: Changes for page buffering/cache are not in place yet.
 *                    Index entries are constructed at the front end by the
 *                    writer and verified at the back end by the reader.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; October 2018
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_reader_md_concur(void)
{
    unsigned i = 0;             /* Local index variables */
    uint8_t *buf = NULL;        /* Data page from the page buffer */
    hid_t dcpl = -1;            /* Dataset creation property list */
    hid_t sid = -1;             /* Dataspace ID */
    hid_t did = -1;             /* Dataset ID */
    int *rwbuf = NULL;          /* Data buffer for writing */
    H5O_info_t oinfo;           /* Object metadata information */
    char dname[100];            /* Name of dataset */
    hsize_t dims[2] = {50, 20}; /* Dataset dimension sizes */
    hsize_t max_dims[2] =       /* Dataset maximum dimension sizes */
        {H5S_UNLIMITED, H5S_UNLIMITED};
    hsize_t chunk_dims[2] = {2, 5}; /* Dataset chunked dimension sizes */
    unsigned num_entries = 0 ;  /* Number of entries in the index */
    H5FD_vfd_swmr_idx_entry_t *index = NULL;  /* Pointer to the index entries */

    hid_t fcpl = -1;            /* File creation property list */
    hid_t fid_writer = -1;      /* File ID for writer */
    hid_t fapl_writer = -1;     /* File access property list for writer */
    H5F_vfd_swmr_config_t *config_writer = NULL;    /* VFD SWMR Configuration for writer */
    pid_t tmppid;               /* Child process ID returned by waitpid */
    pid_t childpid = 0;         /* Child process ID */
    int child_status;           /* Status passed to waitpid */
    int child_wait_option=0;    /* Options passed to waitpid */
    int child_exit_val;         /* Exit status of the child */

    int parent_pfd[2];          /* Pipe for parent process as writer */
    int child_pfd[2];           /* Pipe for child process as reader */
    int notify = 0;             /* Notification between parent and child */
    H5F_t *file_writer;         /* File pointer for writer */

    TESTING("Verify the metadata file for VFD SWMR reader");

    /* Allocate memory for the configuration structure */
    if((config_writer = (H5F_vfd_swmr_config_t *)
                        HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;

    HDmemset(config_writer, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Create a copy of the file access property list */
    if((fapl_writer = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR;
    
    /* Set up the VFD SWMR configuration */
    config_writer->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config_writer->tick_len = 1; 
    config_writer->max_lag = 3;
    config_writer->writer = TRUE;
    config_writer->md_pages_reserved = 256;
    HDstrcpy(config_writer->md_file_path, MD_FILENAME);

    /* Set the VFD SWMR configuration in fapl */
    if(H5Pset_vfd_swmr_config(fapl_writer, config_writer) < 0)
        FAIL_STACK_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl_writer, FS_PAGE_SIZE, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    if(H5Pset_file_space_page_size(fcpl, FS_PAGE_SIZE) < 0)
        FAIL_STACK_ERROR;

    /* Create an HDF5 file with VFD SWMR configured */
    if((fid_writer = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl_writer)) < 0)
        FAIL_STACK_ERROR;

    /* Close the file */
    if(H5Fclose(fid_writer) < 0)
        FAIL_STACK_ERROR;

    /* Create 2 pipes */
    if(HDpipe(parent_pfd) < 0)
        FAIL_STACK_ERROR

    if(HDpipe(child_pfd) < 0)
        FAIL_STACK_ERROR

    /* Fork child process */
    if((childpid = HDfork()) < 0)
        FAIL_STACK_ERROR

    /*
     * Child process as reader
     */
    if(childpid == 0) {
        int child_notify = 0;       /* Notification between child and parent */
        hid_t fid_reader = -1;      /* File ID for reader */
        hid_t fapl_reader = -1;     /* File access property list for reader */
        H5F_t *file_reader;         /* File pointer for reader */
        H5F_vfd_swmr_config_t *config_reader = NULL;    /* VFD SWMR configuration for reader */
        unsigned child_num_entries = 0; /* Number of entries passed to reader */
        H5FD_vfd_swmr_idx_entry_t *child_index = NULL;  /* Index passed to reader */

        /* Close unused write end for writer pipe */
        if(HDclose(parent_pfd[1]) < 0)
            HDexit(EXIT_FAILURE);

        /* Close unused read end for reader pipe */
        if(HDclose(child_pfd[0]) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Case A: reader
         *  --verify an empty index 
         */

        /* Wait for notification 1 from parent to start verification */
        while(child_notify != 1) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Allocate memory for the configuration structure */
        if((config_reader = (H5F_vfd_swmr_config_t *)
                            HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
            HDexit(EXIT_FAILURE);

        HDmemset(config_reader, 0, sizeof(H5F_vfd_swmr_config_t));

        /* Set up the VFD SWMR configuration as reader */
        config_reader->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
        config_reader->tick_len = 1;
        config_reader->max_lag = 3;
        config_reader->writer = FALSE;
        config_reader->md_pages_reserved = 256;
        HDstrcpy(config_reader->md_file_path, MD_FILENAME);

        /* Create a copy of the file access property list */
        if((fapl_reader = H5Pcreate(H5P_FILE_ACCESS)) < 0)
            HDexit(EXIT_FAILURE);

        /* Set the VFD SWMR configuration in fapl_reader */
        if(H5Pset_vfd_swmr_config(fapl_reader, config_reader) < 0)
            HDexit(EXIT_FAILURE);

        /* Enable page buffering */
        if(H5Pset_page_buffer_size(fapl_reader, FS_PAGE_SIZE, 0, 0) < 0)
            HDexit(EXIT_FAILURE);

        /* Open the test file as reader */
        if((fid_reader = H5Fopen(FILENAME, H5F_ACC_RDONLY, fapl_reader)) < 0)
            HDexit(EXIT_FAILURE);

        /* Get file pointer */
        file_reader = (H5F_t *)H5VL_object(fid_reader);

        /* Read and verify header and an empty index in the metadata file */
        if(H5FD__vfd_swmr_reader_md_test(file_reader->shared->lf, 0, NULL) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 2 to parent that the verification is complete */
        child_notify = 2;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Case B: reader
         * --verify index as sent from writer
         */

        /* Wait for notification 3 from parent to start verification */
        while(child_notify != 3) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Read num_entries from writer pipe */
        if(HDread(parent_pfd[0], &child_num_entries, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);
        
        /* Free previous index */
        if(child_index)
            HDfree(child_index);

        if(child_num_entries) {

            /* Allocate memory for num_entries index */
            if((child_index = (H5FD_vfd_swmr_idx_entry_t *)
                          HDcalloc(child_num_entries, 
                                   sizeof(H5FD_vfd_swmr_idx_entry_t))) == NULL)
                HDexit(EXIT_FAILURE);

            /* Read index from writer pipe */
            if(HDread(parent_pfd[0], child_index, 
                     child_num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)

                HDexit(EXIT_FAILURE);
        }

        /* Read and verify the expected header and index info in the 
        * metadata file 
        */
        if(H5FD__vfd_swmr_reader_md_test(file_reader->shared->lf, 
                                        child_num_entries, child_index) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 4 to parent that the verification is complete */
        child_notify = 4;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Case C: reader
         * --verify index as sent from writer
         */

        /* Wait for notification 5 from parent to start verification */
        while(child_notify != 5) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Read num_entries from writer pipe */
        if(HDread(parent_pfd[0], &child_num_entries, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);
        
        /* Free previous index */
        if(child_index)
            HDfree(child_index);

        if(child_num_entries) {
            /* Allocate memory for num_entries index */
            if((child_index = (H5FD_vfd_swmr_idx_entry_t *)
                           HDcalloc(child_num_entries, 
                                    sizeof(H5FD_vfd_swmr_idx_entry_t))) == NULL)
                HDexit(EXIT_FAILURE);

            /* Read index from writer pipe */
            if(HDread(parent_pfd[0], child_index, 
                     child_num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Read and verify the expected header and index info in the 
         * metadata file 
         */
        if(H5FD__vfd_swmr_reader_md_test(file_reader->shared->lf, 
                                         child_num_entries, child_index) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 6 to parent that the verification is complete */
        child_notify = 6;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Case D: reader
         * --verify index as sent from writer
         */

        /* Wait for notification 7 from parent to start verification */
        while(child_notify != 7) {

            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)

                HDexit(EXIT_FAILURE);
        }

        /* Read num_entries from writer pipe */
        if(HDread(parent_pfd[0], &child_num_entries, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);
        
        /* Free previous index */
        if(child_index)
            HDfree(child_index);

        if(child_num_entries) {
            /* Allocate memory for num_entries index */
            if((child_index = (H5FD_vfd_swmr_idx_entry_t *)
                           HDcalloc(child_num_entries, 
                                    sizeof(H5FD_vfd_swmr_idx_entry_t))) == NULL)
                HDexit(EXIT_FAILURE);

            /* Read index from writer pipe */
            if(HDread(parent_pfd[0], child_index, 
                     child_num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Read and verify the expected header and index info in the 
         * metadata file 
         */
        if(H5FD__vfd_swmr_reader_md_test(file_reader->shared->lf, 
                                         child_num_entries, child_index) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 8 to parent that the verification is complete */
        child_notify = 8;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Case E: reader
         * --verify an empty index 
         */

        /* Wait for notification 9 from parent to start verification */
        while(child_notify != 9) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Read and verify header and an empty index in the metadata file */
        if(H5FD__vfd_swmr_reader_md_test(file_reader->shared->lf, 0, NULL) < 0)
            HDexit(EXIT_FAILURE);

        /* Free resources */
        if(child_index)
            HDfree(child_index);
        if(config_reader)
            HDfree(config_reader);

        /* Closing */
        if(H5Fclose(fid_reader) < 0)
            HDexit(EXIT_FAILURE);
        if(H5Pclose(fapl_reader) < 0)
            HDexit(EXIT_FAILURE);

        /* Close the pipes */
        if(HDclose(parent_pfd[0]) < 0)
            HDexit(EXIT_FAILURE);
        if(HDclose(child_pfd[1]) < 0)
            HDexit(EXIT_FAILURE);

        HDexit(EXIT_SUCCESS);
    } /* end child process */

    /* 
     * Parent process as writer
     */

    /* Close unused read end for writer pipe */
    if(HDclose(parent_pfd[0]) < 0)
        FAIL_STACK_ERROR

    /* Close unused write end for reader pipe */
    if(HDclose(child_pfd[1]) < 0)
        FAIL_STACK_ERROR

    /* 
     * Case A: writer
     * --open the file as VFD SWMR writer
     */

    /* Open as VFD SWMR writer */
    if((fid_writer = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl_writer)) < 0)
        FAIL_STACK_ERROR;

    /* Send notification 1 to reader to start verfication */
    notify = 1;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Case B: writer
     *  --create datasets to ensure ticks elapse
     *  --construct 12 entries in the index 
     *  --update the metadata file with the index
     */

    /* Wait for notification 2 from reader that the verifcation is complete */
    while(notify != 2) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /* Create dataset creation property list */
    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set to use chunked dataset */
    if(H5Pset_chunk(dcpl, 2, chunk_dims) < 0)
        FAIL_STACK_ERROR

    /* Create dataspace */
    if((sid = H5Screate_simple(2, dims, max_dims)) < 0)
        FAIL_STACK_ERROR

    /* Perform activities to ensure that ticks elapse */
    for(i = 0; i < 2000; i++) {

        /* Create a chunked dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dcreate2(fid_writer, dname, H5T_NATIVE_INT, sid, 
                             H5P_DEFAULT, dcpl, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Get dataset object header address */
        if(H5Oget_info2(did, &oinfo, H5O_INFO_BASIC) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    num_entries = 12;

    /* Allocate num_entries for the data buffer */
    if((buf = HDcalloc(num_entries, FS_PAGE_SIZE)) == NULL)
        FAIL_STACK_ERROR;

    /* Allocate memory for num_entries index */
    index = HDcalloc(num_entries, sizeof(H5FD_vfd_swmr_idx_entry_t));
    if(NULL == index)
        FAIL_STACK_ERROR;

    /* Construct index for updating the metadata file */
    for(i = 0; i < num_entries; i++) {
        index[i].hdf5_page_offset = 3 + 7 * i;
        index[i].md_file_page_offset = 1 + (num_entries - i) * 5;
        index[i].length = (uint32_t)FS_PAGE_SIZE;
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];
    }

    /* Get the file pointer */
    file_writer = (H5F_t *)H5VL_object(fid_writer);

    /* Update the metadata file with the index */
    if(H5F_update_vfd_swmr_metadata_file(file_writer, num_entries, index) < 0)
        TEST_ERROR;

    /* Send notification 3 to child to start verification */
    notify = 3;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send num_entries to the reader */
    if(HDwrite(parent_pfd[1], &num_entries, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send index to the reader */
    if(HDwrite(parent_pfd[1], index, 
               num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Case C: writer
     *  --write to the datasets to ensure ticks elapse
     *  --update 3 entries in the index 
     *  --update the metadata file with the index
     */

    /* Wait for notification 4 from reader that the verifcation is complete */
    while(notify != 4) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /* Allocate memory for the read/write buffer */
    if((rwbuf = (int *)HDmalloc(sizeof(int) * (50 * 20))) == NULL)
        FAIL_STACK_ERROR;
    for(i = 0; i < (50 * 20); i++)
        rwbuf[i] = (int)i;

    /* Perform activities to ensure that max_lag ticks elapse */
    for(i = 0; i < 1000; i++) {
        /* Open the dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dopen2(fid_writer, dname, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Write to the dataset */
        if(H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, 
                    H5P_DEFAULT, rwbuf) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* Update 3 entries in the index */
    num_entries = 3;
    for(i = 0; i < num_entries; i++)
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];
    
    /* Update the metadata file with the index */
    if(H5F_update_vfd_swmr_metadata_file(file_writer, num_entries, index) < 0)
        TEST_ERROR;

    /* Send notification 5 to reader to start verification */
    notify = 5;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send num_entries to the reader */
    if(HDwrite(parent_pfd[1], &num_entries, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send index to the reader */
    if(HDwrite(parent_pfd[1], index, 
               num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Case D: writer
     *  --read from the datasets to ensure ticks elapse
     *  --update 5 entries in the index 
     *  --update the metadata file with the index
     */

    /* Wait for notification 6 from reader that the verifcation is complete */
    while(notify != 6) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /* Perform activities to ensure that max_lag ticks elapse */
    for(i = 0; i < 1000; i++) {
        /* Open the dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dopen2(fid_writer, dname, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Read from the dataset */
        if(H5Dread(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, 
                   H5P_DEFAULT, rwbuf) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* Update 5 entries in the index */
    num_entries = 5;
    for(i = 0; i < num_entries; i++)
        index[i].entry_ptr = &buf[i * FS_PAGE_SIZE];
    
    /* Update the metadata file with the index */
    if(H5F_update_vfd_swmr_metadata_file(file_writer, num_entries, index) < 0)
        TEST_ERROR;

    /* Send notification 7 to reader to start verification */
    notify = 7;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send num_entries to the reader */
    if(HDwrite(parent_pfd[1], &num_entries, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Send index to the reader */
    if(HDwrite(parent_pfd[1], index, 
               num_entries * sizeof(H5FD_vfd_swmr_idx_entry_t)) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Case E: writer
     * --write to the datasets again to ensure ticks elapse
     * --update the metadata file with an empty index
     */

    /* Wait for notification 8 from reader that the verifcation is complete */
    while(notify != 8) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /* Perform activities to ensure that ticks elapse */
    for(i = 0; i < 1000; i++) {
        /* Open the dataset */
        sprintf(dname, "dset %d", i);
        if((did = H5Dopen2(fid_writer, dname, H5P_DEFAULT)) < 0)
            FAIL_STACK_ERROR

        /* Write to the dataset */
        if(H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, 
                    H5P_DEFAULT, rwbuf) < 0)
            FAIL_STACK_ERROR

        /* Close the dataset */
        if(H5Dclose(did) < 0)
            FAIL_STACK_ERROR
    }

    /* Update the metadata file with 0 entries and NULL index */
    if(H5F_update_vfd_swmr_metadata_file(file_writer, 0, NULL) < 0)
        TEST_ERROR;

    /* Send notification 8 to reader to start verification */
    notify = 9;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /*
     * Done
     */

    /* Close the pipes */
    if(HDclose(parent_pfd[1]) < 0)
        FAIL_STACK_ERROR;
    if(HDclose(child_pfd[0]) < 0)
        FAIL_STACK_ERROR;

    /* Wait for child process to complete */
    if((tmppid = HDwaitpid(childpid, &child_status, child_wait_option)) < 0)
        FAIL_STACK_ERROR

    /* Check exit status of child process */
    if(WIFEXITED(child_status)) {
        if((child_exit_val = WEXITSTATUS(child_status)) != 0)
            TEST_ERROR
    } else { /* child process terminated abnormally */
        TEST_ERROR
    }

    /* Closing */
    if(H5Fclose(fid_writer) < 0)
        FAIL_STACK_ERROR
    if(H5Pclose(fapl_writer) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    /* Free resources */
    if(config_writer)
        HDfree(config_writer);
     if(buf)
        HDfree(buf);
    if(rwbuf)
        HDfree(rwbuf);
    if(index)
        HDfree(index);

    PASSED();
    return 0;

error:
    if(config_writer)
        HDfree(config_writer);
     if(buf)
        HDfree(buf);
    if(rwbuf)
        HDfree(rwbuf);
    if(index)
        HDfree(index);

    H5E_BEGIN_TRY {
        H5Pclose(fapl_writer);
        H5Fclose(fid_writer);
        H5Pclose(fcpl);
    } H5E_END_TRY;

    return 1;
} /* test_reader_md_concur() */

#endif /* !(defined(H5_HAVE_FORK) && defined(H5_HAVE_WAITPID) && defined(H5_HAVE_FLOCK)) */

/*-------------------------------------------------------------------------
 * Function:    test_multiple_file_opens()
 *
 * Purpose:     Verify the entries on the EOT queue when opening files
 *              with and without VFD SWMR configured.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; 11/18/2019
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_multiple_file_opens(void) 
{
    hid_t fid1 = -1;        /* File ID */
    hid_t fid2 = -1;        /* File ID */
    hid_t fid = -1;         /* File ID */
    hid_t fcpl = -1;        /* File creation property list ID */
    hid_t fapl1 = -1;       /* File access property list ID */
    hid_t fapl2 = -1;       /* File access property list ID */
    H5F_t *f1, *f2, *f;     /* File pointer */
    H5F_vfd_swmr_config_t *config1 = NULL;      /* Configuration for VFD SWMR */
    H5F_vfd_swmr_config_t *config2 = NULL;      /* Configuration for VFD SWMR */
    eot_queue_entry_t *curr;

    TESTING("EOT queue entries when opening files with/without VFD SWMR");

    /* Allocate memory for the configuration structure */
    if((config1 = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    if((config2 = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    HDmemset(config1, 0, sizeof(H5F_vfd_swmr_config_t));
    HDmemset(config2, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Configured as VFD SWMR writer */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 6;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Create a copy of the file access property list */
    if((fapl2 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Configured as VFD SWMR writer */
    config2->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config2->tick_len = 4; 
    config2->max_lag = 6;
    config2->writer = TRUE;
    config2->md_pages_reserved = 2;
    HDstrcpy(config2->md_file_path, MD_FILENAME2);

    /* Should succeed in setting the VFD SWMR configuration */
    if(H5Pset_vfd_swmr_config(fapl2, config2) < 0)
        TEST_ERROR;

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
            FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl2, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Create a file without VFD SWMR */
    if((fid = H5Fcreate(FNAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Get a pointer to the internal file object */
    if(NULL == (f = (H5F_t *)H5VL_object(fid)))
        FAIL_STACK_ERROR

    /* Verify the global vfd_swmr_writer_g is not set */
    if(vfd_swmr_writer_g)
        TEST_ERROR;
    /* The EOT queue should be empty */
    if(!TAILQ_EMPTY(&eot_queue_g))
        TEST_ERROR;

    /* Create a file with VFD SWMR writer */
    if((fid1 = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl1)) < 0)
        TEST_ERROR;

    /* Get a pointer to the internal file object */
    if(NULL == (f1 = (H5F_t *)H5VL_object(fid1)))
        FAIL_STACK_ERROR

    /* The global vfd_swmr_writer_g should be set */
    if(!vfd_swmr_writer_g)
        TEST_ERROR;
    /* The EOT queue should be initialized with the first entry equals to f1 */
    if((curr = TAILQ_FIRST(&eot_queue_g)) == NULL || curr->vfd_swmr_file != f1)
        TEST_ERROR;

    /* Create another file with VFD SWMR writer */
    if((fid2 = H5Fcreate(FILENAME2, H5F_ACC_TRUNC, fcpl, fapl2)) < 0)
        TEST_ERROR;

    /* Get a pointer to the internal file object */
    if(NULL == (f2 = (H5F_t *)H5VL_object(fid2)))
        FAIL_STACK_ERROR

    /* The global vfd_swmr_writer_g should still be set */
    if(!vfd_swmr_writer_g)
        TEST_ERROR;
    /* The EOT queue's first entry should be f1 */
    if((curr = TAILQ_FIRST(&eot_queue_g)) == NULL || curr->vfd_swmr_file != f1)
        TEST_ERROR;

    /* The file without VFD SWMR should not exist on the EOT queue */
    TAILQ_FOREACH(curr, &eot_queue_g, link) {
        if(curr->vfd_swmr_file == f)
            TEST_ERROR
    }

    /* Close the first file with VFD SWMR */
    if(H5Fclose(fid1) < 0)
        FAIL_STACK_ERROR;

    /* The global vfd_swmr_writer_g should still be set */
    if(!vfd_swmr_writer_g)
        TEST_ERROR;
    /* The EOT queue's first entry should be f2 */
    if((curr = TAILQ_FIRST(&eot_queue_g)) == NULL || curr->vfd_swmr_file != f2)
        TEST_ERROR;

    /* Close the second file with VFD SWMR */
    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;

    /* The global vfd_swmr_writer_g should not be set */
    if(vfd_swmr_writer_g)
        TEST_ERROR;
    /* The EOT queue should be empty */
    if(!TAILQ_EMPTY(&eot_queue_g))
        TEST_ERROR;

    /* Closing */
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl2) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Free buffers */
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);

    PASSED();
    return 0;

error:
    H5E_BEGIN_TRY {
        H5Pclose(fapl1);
        H5Pclose(fapl2);
        H5Pclose(fcpl);
        H5Fclose(fid);
        H5Fclose(fid1);
        H5Fclose(fid2);
    } H5E_END_TRY;
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);

    return 1;
} /* test_multiple_file_opens() */

/*-------------------------------------------------------------------------
 * Function:    test_multiple_concur_file_opens()
 *
 * Purpose:     Verify the entries on the EOT queue when opening files
 *              with and without VFD SWMR configured.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; 11/18/2019
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_multiple_concur_file_opens(void)
{
    hid_t fcpl = -1;            /* File creation property list */
    pid_t tmppid;               /* Child process ID returned by waitpid */
    pid_t childpid = 0;         /* Child process ID */
    int child_status;           /* Status passed to waitpid */
    int child_wait_option=0;    /* Options passed to waitpid */
    int child_exit_val;         /* Exit status of the child */
    int parent_pfd[2];          /* Pipe for parent process as writer */
    int child_pfd[2];           /* Pipe for child process as reader */
    int notify = 0;             /* Notification between parent and child */
    hid_t fid1, fid2;           /* File IDs */
    hid_t fapl1, fapl2;         /* File access property list */
    H5F_vfd_swmr_config_t *config1 = NULL;    /* VFD SWMR configuration */
    H5F_vfd_swmr_config_t *config2 = NULL;    /* VFD SWMR configuration */
    H5F_t *f1, *f2;             /* File pointer */
    eot_queue_entry_t *curr;

    TESTING("EOT queue entries when opening files concurrently with VFD SWMR");

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
        FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    if(H5Pset_file_space_page_size(fcpl, FS_PAGE_SIZE) < 0)
        FAIL_STACK_ERROR;

    /* Create file A */
    if((fid1 = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, H5P_DEFAULT)) < 0)
        FAIL_STACK_ERROR;

    /* Close the file */
    if(H5Fclose(fid1) < 0)
        FAIL_STACK_ERROR;

    /* Create file B */
    if((fid2 = H5Fcreate(FILENAME2, H5F_ACC_TRUNC, fcpl, H5P_DEFAULT)) < 0)
        FAIL_STACK_ERROR;

    /* Close the file */
    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;

    /* Create 2 pipes */
    if(HDpipe(parent_pfd) < 0)
        FAIL_STACK_ERROR

    if(HDpipe(child_pfd) < 0)
        FAIL_STACK_ERROR

    /* Fork child process */
    if((childpid = HDfork()) < 0)
        FAIL_STACK_ERROR

    /*
     * Child process
     */
    if(childpid == 0) {
        int child_notify = 0;       /* Notification between child and parent */
        hid_t fid_writer = -1;      /* File ID for writer */
        hid_t fapl_writer = -1;     /* File access property list for writer */
        H5F_vfd_swmr_config_t *config_writer = NULL;    /* VFD SWMR configuration for reader */

        /* Close unused write end for writer pipe */
        if(HDclose(parent_pfd[1]) < 0)
            HDexit(EXIT_FAILURE);

        /* Close unused read end for reader pipe */
        if(HDclose(child_pfd[0]) < 0)
            HDexit(EXIT_FAILURE);

        /* 
         * Set up and open file B as VFD SWMR writer
         */

        /* Wait for notification 1 from parent before opening file B */
        while(child_notify != 1) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        /* Allocate memory for VFD SMWR configuration */
        if((config_writer = (H5F_vfd_swmr_config_t *)
                            HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
            HDexit(EXIT_FAILURE);

        HDmemset(config_writer, 0, sizeof(H5F_vfd_swmr_config_t));

        /* Set up the VFD SWMR configuration */
        config_writer->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
        config_writer->tick_len = 1;
        config_writer->max_lag = 3;
        config_writer->writer = TRUE;
        config_writer->md_pages_reserved = 256;
        HDstrcpy(config_writer->md_file_path, MD_FILENAME2);

        /* Create a copy of the file access property list */
        if((fapl_writer = H5Pcreate(H5P_FILE_ACCESS)) < 0)
            HDexit(EXIT_FAILURE);

        /* Set the VFD SWMR configuration in fapl_writer */
        if(H5Pset_vfd_swmr_config(fapl_writer, config_writer) < 0)
            HDexit(EXIT_FAILURE);

        /* Enable page buffering */
        if(H5Pset_page_buffer_size(fapl_writer, FS_PAGE_SIZE, 0, 0) < 0)
            HDexit(EXIT_FAILURE);

        /* Open file B as VFD SWMR writer */
        if((fid_writer = H5Fopen(FILENAME2, H5F_ACC_RDWR, fapl_writer)) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 2 to parent that file B is open */
        child_notify = 2;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* Wait for notification 3 from parent before closing file B */
        while(child_notify != 3) {
            if(HDread(parent_pfd[0], &child_notify, sizeof(int)) < 0)
                HDexit(EXIT_FAILURE);
        }

        if(config_writer )
            HDfree(config_writer);

        /* Close the file */
        if(H5Fclose(fid_writer) < 0)
            HDexit(EXIT_FAILURE);
        if(H5Pclose(fapl_writer) < 0)
            HDexit(EXIT_FAILURE);

        /* Send notification 4 to parent that file B is closed */
        child_notify = 4;
        if(HDwrite(child_pfd[1], &child_notify, sizeof(int)) < 0)
            HDexit(EXIT_FAILURE);

        /* Close the pipes */
        if(HDclose(parent_pfd[0]) < 0)
            HDexit(EXIT_FAILURE);
        if(HDclose(child_pfd[1]) < 0)
            HDexit(EXIT_FAILURE);

        HDexit(EXIT_SUCCESS);
    } /* end child process */

    /* 
     * Parent process
     */

    /* Close unused read end for writer pipe */
    if(HDclose(parent_pfd[0]) < 0)
        FAIL_STACK_ERROR

    /* Close unused write end for reader pipe */
    if(HDclose(child_pfd[1]) < 0)
        FAIL_STACK_ERROR

    /* 
     * Set up and open file A as VFD SWMR writer
     */

    /* Allocate memory for VFD SWMR configuration */
    if((config1 = (H5F_vfd_swmr_config_t *) HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR

    HDmemset(config1, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Set up the VFD SWMR configuration */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 7;
    config1->max_lag = 10;
    config1->writer = TRUE;
    config1->md_pages_reserved = 256;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR

    /* Set the VFD SWMR configuration in fapl1 */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        FAIL_STACK_ERROR

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, FS_PAGE_SIZE, 0, 0) < 0)
        FAIL_STACK_ERROR

    /* Open file A as VFD SWMR writer */
    if((fid1 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1)) < 0)
        FAIL_STACK_ERROR;

    /* Get a pointer to the internal file object */
    if(NULL == (f1 = (H5F_t *)H5VL_object(fid1)))
        FAIL_STACK_ERROR

    /* The global vfd_swmr_writer_g should be set */
    if(!vfd_swmr_writer_g)
        TEST_ERROR;

    /* The EOT queue's first entry should be f1 */
    if((curr = TAILQ_FIRST(&eot_queue_g)) == NULL || curr->vfd_swmr_file != f1)
        TEST_ERROR;


    /* Send notification 1 to child to open file B */
    notify = 1;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Wait for notification 2 from child that file B is open */
    while(notify != 2) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /* Open file B as VFD SWMR reader */

    /* Allocate memory for VFD SWMR configuration */
    if((config2 = (H5F_vfd_swmr_config_t *) HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR

    HDmemset(config2, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Set up the VFD SWMR configuration */
    config2->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config2->tick_len = 1;
    config2->max_lag = 3;
    config2->writer = FALSE;
    config2->md_pages_reserved = 256;
    HDstrcpy(config2->md_file_path, MD_FILENAME2);

    /* Create a copy of the file access property list */
    if((fapl2 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        FAIL_STACK_ERROR

    /* Set the VFD SWMR configuration in fapl2 */
    if(H5Pset_vfd_swmr_config(fapl2, config2) < 0)
        FAIL_STACK_ERROR

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl2, FS_PAGE_SIZE, 0, 0) < 0)
        FAIL_STACK_ERROR

    /* Open file B as VFD SWMR reader */
    if((fid2 = H5Fopen(FILENAME2, H5F_ACC_RDONLY, fapl2)) < 0)
        FAIL_STACK_ERROR;

    /* Get a pointer to the internal file object */
    if(NULL == (f2 = (H5F_t *)H5VL_object(fid2)))
        FAIL_STACK_ERROR

    /* The global vfd_swmr_writer_g should not be set */
    if(vfd_swmr_writer_g)
        TEST_ERROR;

    /* The EOT queue's first entry should be f2 */
    if((curr = TAILQ_FIRST(&eot_queue_g)) == NULL || curr->vfd_swmr_file != f2)
        TEST_ERROR;

    /* Send notification 3 to child to close file B */
    notify = 3;
    if(HDwrite(parent_pfd[1], &notify, sizeof(int)) < 0)
        FAIL_STACK_ERROR;

    /* Wait for notification 4 from child that file B is closed */
    while(notify != 4) {
        if(HDread(child_pfd[0], &notify, sizeof(int)) < 0)
            FAIL_STACK_ERROR;
    }

    /*
     * Done
     */

    /* Close the pipes */
    if(HDclose(parent_pfd[1]) < 0)
        FAIL_STACK_ERROR;
    if(HDclose(child_pfd[0]) < 0)
        FAIL_STACK_ERROR;

    /* Wait for child process to complete */
    if((tmppid = HDwaitpid(childpid, &child_status, child_wait_option)) < 0)
        FAIL_STACK_ERROR

    /* Check exit status of child process */
    if(WIFEXITED(child_status)) {
        if((child_exit_val = WEXITSTATUS(child_status)) != 0)
            TEST_ERROR
    } else { /* child process terminated abnormally */
        TEST_ERROR
    }

    /* Closing */
    if(H5Fclose(fid1) < 0)
        FAIL_STACK_ERROR
    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR
    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fapl2) < 0)
        FAIL_STACK_ERROR;
    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    /* Free resources */
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);

    PASSED();
    return 0;

error:
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);

    H5E_BEGIN_TRY {
        H5Pclose(fapl1);
        H5Pclose(fapl2);
        H5Fclose(fid1);
        H5Fclose(fid2);
        H5Pclose(fcpl);
    } H5E_END_TRY;

    return 1;
} /* test_multiple_concur_file_opens() */


/*-------------------------------------------------------------------------
 *  Function:    test_same_file_opens()
 *
 *  Purpose:     Verify multiple opens of the same file as listed below:
 *
 *                #1st open#                     
 *  #2nd open#    VW  VR   W   R 
 *              ------------------
 *          VW  |  s   f   f   f | 
 *          VR  |  f   f   f   f | 
 *           W  |  f   f   s   f | 
 *           R  |  f   f   s   s |       
 *              ------------------
 *
 *  Notations:
 *        W:  H5F_ACC_RDWR
 *        R:  H5F_ACC_RDONLY
 *        VW: VFD SWMR writer
 *        VR: VFD SWMR reader
 *
 *        f: the open fails 
 *        s: the open succeeds 
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 * Programmer:  Vailin Choi; October 2019
 *
 *-------------------------------------------------------------------------
 */
static unsigned
test_same_file_opens(void)
{
    hid_t fid = -1;         /* File ID */
    hid_t fid2 = -1;        /* File ID */
    hid_t fcpl = -1;        /* File creation property list ID */
    hid_t fapl1 = -1;       /* File access property list ID */
    hid_t fapl2 = -1;       /* File access property list ID */
    H5F_vfd_swmr_config_t *config1 = NULL;      /* Configuration for VFD SWMR */
    H5F_vfd_swmr_config_t *config2 = NULL;      /* Configuration for VFD SWMR */

    TESTING("Multiple opens of the same file with VFD SWMR configuration");

    /* Should succeed without VFD SWMR configured */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Close the file  */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* Allocate memory for the configuration structure */
    if((config1 = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    if((config2 = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
        FAIL_STACK_ERROR;
    HDmemset(config1, 0, sizeof(H5F_vfd_swmr_config_t));
    HDmemset(config2, 0, sizeof(H5F_vfd_swmr_config_t));

    /* Create a copy of the file creation property list */
    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
            FAIL_STACK_ERROR

    /* Set file space strategy */
    if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, 1) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Tests for first column
     */

    /* Create the test file */
    if((fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Close the file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;


    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR writer */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 10;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Set the VFD SWMR configuration in fapl1 */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Open the file as VFD SWMR writer */
    /* Keep the file open */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1)) < 0)
        TEST_ERROR;

    /* Open the same file again as VFD SWMR writer */
    /* Should succeed: 1st open--VFD SWMR writer, 2nd open--VFD SWMR writer */
    if((fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1)) < 0)
        TEST_ERROR;

    /* Close the second file open */
    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;

    /* Create a copy of the file access property list */
    if((fapl2 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR reader */
    config2->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config2->tick_len = 3; 
    config2->max_lag = 8;
    config2->writer = FALSE;
    config2->md_pages_reserved = 3;
    HDstrcpy(config2->md_file_path, MD_FILENAME);

    if(H5Pset_vfd_swmr_config(fapl2, config2) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl2, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Open the same file again as VFD SWMR reader */
    /* Should fail: 1st open--VFD SWMR writer, 2nd open--VFD SWMR reader */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDONLY, fapl2);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;
    
    if(H5Pclose(fapl2) < 0)
        FAIL_STACK_ERROR;


    /* Open the same file again as regular writer */
    /* Should fail: 1st open--VFD SWMR writer, 2nd open--regular writer */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, H5P_DEFAULT);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    /* Open the same file again as regular reader */
    /* Should fail: 1st open--VFD SWMR writer, 2nd open--regular reader */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    /* Close the 1st open file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;


    /* 
     * Tests for second column
     */

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR reader */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 10;
    config1->writer = FALSE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    /* Set up the configuration in fapl1 */
    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Open the file as VFD SWMR reader */
    /* Should fail because there is no metadata file */
    /* Take a while to complete due to retries */
    H5E_BEGIN_TRY {
        fid = H5Fopen(FILENAME, H5F_ACC_RDONLY, fapl1);
    } H5E_END_TRY;
    if(fid >= 0)
        TEST_ERROR;

    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Tests for third column
     */

    /* Open the file as regular writer */
    /* Keep the file open */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR writer */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 10;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Open the same file again as VFD SWMR writer */
    /* Should fail: 1st open--regular writer, 2nd open--VFD SWMR writer */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;


    /* Open the same file again as regular writer */
    /* Should succeed: 1st open--regular writer, 2nd open--regular writer */
    if((fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;


    /* Open the same file again as regular reader */
    /* Should succeed: 1st open is writer, 2nd open is the same file as reader */
    if((fid2 = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;

    /* Close the 1st open file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    /* 
     * Tests for fourth column
     */

    /* Open the file as regular reader */
    /* keep the file open */
    if((fid = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    /* Create a copy of the file access property list */
    if((fapl1 = H5Pcreate(H5P_FILE_ACCESS)) < 0)
        TEST_ERROR;

    /* Set up as VFD SWMR writer */
    config1->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
    config1->tick_len = 4; 
    config1->max_lag = 10;
    config1->writer = TRUE;
    config1->md_pages_reserved = 2;
    HDstrcpy(config1->md_file_path, MD_FILENAME);

    if(H5Pset_vfd_swmr_config(fapl1, config1) < 0)
        TEST_ERROR;

    /* Enable page buffering */
    if(H5Pset_page_buffer_size(fapl1, 4096, 0, 0) < 0)
        FAIL_STACK_ERROR;

    /* Open the same file again as VFD SMWR writer */
    /* Should fail: 1st open--regular reader, 2nd open--VFD SWMR writer */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl1);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    if(H5Pclose(fapl1) < 0)
        FAIL_STACK_ERROR;

    /* Open the same file again as regular reader */
    /* Should succeed: 1st open--regular reader, 2nd open--regular reader */
    if((fid2 = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT)) < 0)
        TEST_ERROR;

    if(H5Fclose(fid2) < 0)
        FAIL_STACK_ERROR;

    /* Open the same file again as regular writer */
    /* Should fail: 1st open--regular reader, 2nd open--regular writer */
    H5E_BEGIN_TRY {
        fid2 = H5Fopen(FILENAME, H5F_ACC_RDWR, H5P_DEFAULT);
    } H5E_END_TRY;
    if(fid2 >= 0)
        TEST_ERROR;

    /* Close the 1st open file */
    if(H5Fclose(fid) < 0)
        FAIL_STACK_ERROR;

    if(H5Pclose(fcpl) < 0)
        FAIL_STACK_ERROR;

    /* Free buffers */
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);

    PASSED();
    return 0;

error:
    H5E_BEGIN_TRY {
        H5Pclose(fapl1);
        H5Pclose(fapl2);
        H5Pclose(fcpl);
        H5Fclose(fid);
        H5Fclose(fid2);
    } H5E_END_TRY;
    if(config1)
        HDfree(config1);
    if(config2)
        HDfree(config2);
    return 1;
} /* test_same_file_opens() */

#ifndef _arraycount
#define _arraycount(_a) (sizeof(_a)/sizeof(_a[0]))
#endif

/* Fetch a variable from the environment and parse it for unsigned long
 * content.  Return 0 if the variable is not present, -1 if it is present
 * but it does not parse and compare less than `limit`, 1 if it's present,
 * parses, and is in-bounds.
 */
static int
fetch_env_ulong(const char *varname, unsigned long limit, unsigned long *valp)
{
    char *end;
    unsigned long ul;
    char *tmp;

    if ((tmp = getenv(varname)) == NULL)
        return 0;

    errno = 0;
    ul = strtoul(tmp, &end, 0);
    if ((ul == ULONG_MAX && errno != 0) || end == tmp || *end != '\0') {
        fprintf(stderr, "could not parse %s: %s\n", varname, strerror(errno));
        return -1;
    }
    if (ul > limit) {
        fprintf(stderr, "%s (%lu) out of range\n", varname, ul);
        return -1;
    }
    *valp = ul;
    return 1;
}

static unsigned
test_shadow_index_lookup(void)
{
    unsigned nerrors = 0;
    H5FD_vfd_swmr_idx_entry_t *idx;
    uint32_t size[] = {0, 1, 2, 3, 4, 0};
    char vector[8];
    unsigned seed = 1;
    unsigned i, j, failj;
    bool have_failj = false;
    unsigned long tmpl;
    char *ostate;
    const char *seedvar = "H5_SHADOW_INDEX_SEED";
    const char *failvar = "H5_SHADOW_INDEX_FAIL";

    TESTING("Shadow-index lookups");

    /* get seed from environment or else from time(3) */
    switch (fetch_env_ulong(seedvar, UINT_MAX, &tmpl)) {
    case -1:
        nerrors = 1;
        goto out;
    case 0:
        seed = (unsigned int)time(NULL);
        break;
    default:
        seed = (unsigned int)tmpl;
        break;
    }

    /* get forced-fail index from environment or else from time(3) */
    switch (fetch_env_ulong(failvar, UINT_MAX, &tmpl)) {
    case -1:
        nerrors = 1;
        goto out;
    case 0:
        break;
    default:
        failj = (unsigned int)tmpl;
        have_failj = true;
        break;
    }

    ostate = initstate(seed, vector, _arraycount(vector));

    size[5] = (uint32_t)(1024 + random() % (16 * 1024 * 1024 - 1024));

    for (i = 0; i < _arraycount(size); i++) {
        uint32_t cursize = size[i];
        const uint64_t modulus = UINT64_MAX / MAX(1, cursize);
        uint64_t pageno;

        idx = calloc(cursize,  sizeof(*idx));
        if (idx == NULL) {
            fprintf(stderr, "couldn't allocate %" PRIu32 " indices\n",
                cursize);
            exit(EXIT_FAILURE);
        }
        for (pageno = (uint64_t)random() % modulus, j = 0;
             j < cursize;
             j++, pageno += (uint64_t)random() % modulus) {
            idx[j].hdf5_page_offset = pageno;
        }
        for (j = 0; j < cursize; j++) {
            H5FD_vfd_swmr_idx_entry_t *found;

            found = vfd_swmr_pageno_to_mdf_idx_entry(idx, cursize,
                idx[j].hdf5_page_offset, false);
            if ((have_failj && failj == j) || found != &idx[j])
                break;
        }
        if (j < cursize) {
            printf("\nshadow-index entry %d lookup, pageno %" PRIu64
                   ", index size %" PRIu32 ", seed %u", j,
                   idx[j].hdf5_page_offset, cursize, seed);
            nerrors++;
        }
        free(idx);
    }
    (void)setstate(ostate);
out:
    if (nerrors == 0)
        PASSED();
    else
        printf(" FAILED\n");
    return nerrors;
}


/*-------------------------------------------------------------------------
 * Function:    main()
 *
 * Purpose:     Main function for VFD SWMR tests.
 *
 * Return:      0 if test is sucessful
 *              1 if test fails
 *
 *-------------------------------------------------------------------------
 */
int
main(void)
{
    hid_t       fapl = -1;              /* File access property list for */
                                        /* data files                    */
    unsigned    nerrors = 0;            /* Cumulative error count */
    char *lock_env_var = NULL;          /* File locking env var pointer */
    const char  *env_h5_drvr = NULL;    /* File Driver value from environment */
    hbool_t use_file_locking;           /* Read from env var */

    /* Check the environment variable that determines if we care
     * about file locking. File locking should be used unless explicitly
     * disabled.
     */
    lock_env_var = HDgetenv("HDF5_USE_FILE_LOCKING");
    if(lock_env_var && !HDstrcmp(lock_env_var, "FALSE"))
        use_file_locking = FALSE;
    else
        use_file_locking = TRUE;

    /* Get the VFD to use */
    env_h5_drvr = HDgetenv("HDF5_DRIVER");
    if(env_h5_drvr == NULL)
        env_h5_drvr = "nomatch";

    /* Temporary skip testing with multi/split drivers:
     * Page buffering depends on paged aggregation which is
     * currently disabled for multi/split drivers.
     */
    if((0 == HDstrcmp(env_h5_drvr, "multi")) || 
       (0 == HDstrcmp(env_h5_drvr, "split"))) {

        SKIPPED()
        HDputs("Skip VFD SWMR test because paged aggregation is disabled for multi/split drivers");
        HDexit(EXIT_SUCCESS);
    } /* end if */

    /* Set up */
    h5_reset();

    if((fapl = h5_fileaccess()) < 0) {
        nerrors++;
        PUTS_ERROR("Can't get VFD-dependent fapl")
    } /* end if */

    nerrors += test_fapl();

    if(use_file_locking) {
        nerrors += test_shadow_index_lookup();
        nerrors += test_file_fapl();
        nerrors += test_file_end_tick();
        nerrors += test_writer_create_open_flush();
        nerrors += test_writer_md();
        nerrors += test_reader_md_concur();
        nerrors += test_multiple_file_opens();
        nerrors += test_multiple_concur_file_opens();
        nerrors += test_same_file_opens();

    }

    if(nerrors)
        goto error;

    HDputs("All VFD SWMR tests passed.");

    HDexit(EXIT_SUCCESS);

error:
    HDprintf("***** %d VFD SWMR TEST%s FAILED! *****\n",
        nerrors, nerrors > 1 ? "S" : "");

    H5E_BEGIN_TRY {
        H5Pclose(fapl);
    } H5E_END_TRY;

    HDexit(EXIT_FAILURE);
}