synced with develop

3 files changed, 579 insertions, 78 deletions

diff --git a/test/CMakeTests.cmake b/test/CMakeTests.cmake
index ae99be1..fca2f27 100644
--- a/test/CMakeTests.cmake
+++ b/test/CMakeTests.cmake
@@ -581,6 +581,7 @@ set (test_CLEANFILES
     cache_logging.out
     vds_swmr.h5
     vds_swmr_src_*.h5
+    tmp/vds_src_2.h5
 )
 
 # Remove any output file left over from previous test run
diff --git a/test/filter_plugin.c b/test/filter_plugin.c
index 8b7e0e4..9897c84 100644
--- a/test/filter_plugin.c
+++ b/test/filter_plugin.c
@@ -134,7 +134,7 @@ allocate_and_init_2D_array(int ***arr, const hsize_t *sizes, int **initial_value
     return SUCCEED;
 error:
     free_2D_array(arr);
-    
+
     return FAIL;
 } /* end allocate_and_init_2D_array() */
 
@@ -165,7 +165,7 @@ compare_2D_arrays(int **dset1, int **dset2, const hsize_t *sizes, /*OUT*/ hbool_
             }
 
     return SUCCEED;
-    
+
 } /* end compare_2D_arrays() */
 
 
@@ -612,7 +612,7 @@ test_read_data(hid_t did, int *origin_data)
     free_2D_array(&check);
 
     PASSED();
-    
+
     return SUCCEED;
 
 error:
@@ -943,14 +943,14 @@ error:
  *            paths.
  *
  * Return:    SUCCEED/FAIL
- * 
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
 test_path_api_calls(void)
 {
     unsigned int n_starting_paths;
-    unsigned int u;                 
+    unsigned int u;
     unsigned int n_paths;
     herr_t       ret;
     ssize_t      path_len = -1;
@@ -1319,7 +1319,7 @@ error:
  * Purpose:   Turns the chunk cache off
  *
  * Return:    SUCCEED/FAIL
- * 
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1360,37 +1360,36 @@ main(void)
     unsigned    new_format;
     int         nerrors = 0;
 
-    /* Testing setup */
-    h5_reset();
-
     /*******************************************************************/
     /* ENSURE THAT WRITING TO DATASETS AND CREATING GROUPS WORKS       */
     /*******************************************************************/
+    /* Test with old & new format groups */
+    for (new_format = FALSE; new_format <= TRUE; new_format++) {
+        hid_t my_fapl_id;
 
-    /* Get a VFD-dependent filename */
-    if ((old_ff_fapl_id = h5_fileaccess()) < 0)
-        TEST_ERROR;
-
-    /* Turn off the chunk cache, so all the chunks are immediately written to disk */
-    if (disable_chunk_cache(old_ff_fapl_id) < 0)
-        TEST_ERROR;
+        /* Testing setup */
+        h5_reset();
 
-    /* Copy the file access property list and set the latest file format on it */
-    if ((new_ff_fapl_id = H5Pcopy(old_ff_fapl_id)) < 0)
-        TEST_ERROR;
-    if (H5Pset_libver_bounds(new_ff_fapl_id, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
-        TEST_ERROR;
+        /* Get a VFD-dependent filename */
+        if ((old_ff_fapl_id = h5_fileaccess()) < 0)
+            TEST_ERROR;
 
-    /* Fix up the filename for the VFD */
-    h5_fixname(FILENAME[0], old_ff_fapl_id, filename, sizeof(filename));
+        /* Turn off the chunk cache, so all the chunks are immediately written to disk */
+        if (disable_chunk_cache(old_ff_fapl_id) < 0)
+            TEST_ERROR;
 
-    /* Test with old & new format groups */
-    for (new_format = FALSE; new_format <= TRUE; new_format++) {
-        hid_t my_fapl_id;
+        /* Fix up the filename for the VFD */
+        h5_fixname(FILENAME[0], old_ff_fapl_id, filename, sizeof(filename));
 
         /* Set the FAPL for the type of format */
         if (new_format) {
             HDputs("\nTesting with new file format:");
+            /* Copy the file access property list and set the latest file format on it */
+            if ((new_ff_fapl_id = H5Pcopy(old_ff_fapl_id)) < 0)
+                TEST_ERROR;
+            if (H5Pset_libver_bounds(new_ff_fapl_id, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+                TEST_ERROR;
+
             my_fapl_id = new_ff_fapl_id;
         }
         else {
@@ -1410,61 +1409,121 @@ main(void)
 
         if (H5Fclose(fid) < 0)
             TEST_ERROR;
-    } /* end for */
 
-    /* Close FAPLs */
-    if (H5Pclose(old_ff_fapl_id) < 0)
-        TEST_ERROR;
-    if (H5Pclose(new_ff_fapl_id) < 0)
-        TEST_ERROR;
+        /* Close FAPLs */
+        if (H5Pclose(old_ff_fapl_id) < 0)
+            TEST_ERROR;
+        if (new_format) {
+            if (H5Pclose(new_ff_fapl_id) < 0)
+                TEST_ERROR;
+        }
 
-    /* Restore the default error handler (set in h5_reset()) */
-    h5_restore_err();
+        /* Restore the default error handler (set in h5_reset()) */
+        h5_restore_err();
 
-    /*******************************************************************/
-    /* ENSURE THAT READING FROM DATASETS AND OPENING GROUPS WORKS      */
-    /*******************************************************************/
+        /*******************************************************************/
+        /* ENSURE THAT READING FROM DATASETS AND OPENING GROUPS WORKS      */
+        /*******************************************************************/
 
-    HDputs("\nTesting reading data with with dynamic plugin filters:");
+        HDputs("\nTesting reading data with with dynamic plugin filters:");
 
-    /* Close the library so that all loaded plugin libraries are unloaded */
-    h5_reset();
-    if ((old_ff_fapl_id = h5_fileaccess()) < 0)
-        TEST_ERROR;
+        /* Close the library so that all loaded plugin libraries are unloaded */
+        h5_reset();
+        if ((old_ff_fapl_id = h5_fileaccess()) < 0)
+            TEST_ERROR;
 
-    /* Reopen the file for testing data reading */
-    if ((fid = H5Fopen(filename, H5F_ACC_RDONLY, old_ff_fapl_id)) < 0)
-        TEST_ERROR;
+        /* Set the FAPL for the type of format */
+        if (new_format) {
+            /* Copy the file access property list and set the latest file format on it */
+            if ((new_ff_fapl_id = H5Pcopy(old_ff_fapl_id)) < 0)
+                TEST_ERROR;
+            if (H5Pset_libver_bounds(new_ff_fapl_id, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+                TEST_ERROR;
 
-    /* Read the data with filters */
-    nerrors += (test_dataset_read_with_filters(fid) < 0 ? 1 : 0);
+            my_fapl_id = new_ff_fapl_id;
+        }
+        else
+            my_fapl_id = old_ff_fapl_id;
 
-    /* Test creating groups using dynamically-loaded plugin filters */
-    nerrors += (test_opening_groups_using_plugins(fid) < 0  ? 1 : 0);
+        /* Reopen the file for testing data reading */
+        if ((fid = H5Fopen(filename, H5F_ACC_RDONLY, my_fapl_id)) < 0)
+            TEST_ERROR;
 
-    /* Restore the default error handler (set in h5_reset()) */
-    h5_restore_err();
+        /* Read the data with filters */
+        nerrors += (test_dataset_read_with_filters(fid) < 0 ? 1 : 0);
 
-    /*******************************************************************/
-    /* ENSURE THAT DISABLING FILTER PLUGINS VIA THE FILTER FLAGS WORKS */
-    /*******************************************************************/
+        /* Test creating groups using dynamically-loaded plugin filters */
+        nerrors += (test_opening_groups_using_plugins(fid) < 0  ? 1 : 0);
 
-    /* Close the library so that all loaded plugin libraries are unloaded */
-    h5_reset();
-    if ((old_ff_fapl_id = h5_fileaccess()) < 0)
-        TEST_ERROR;
+        /* Close FAPLs */
+        if (H5Pclose(old_ff_fapl_id) < 0)
+            TEST_ERROR;
+        if (new_format) {
+            if (H5Pclose(new_ff_fapl_id) < 0)
+                TEST_ERROR;
+        }
 
-    /* Reopen the file for testing data reading */
-    if ((fid = H5Fopen(filename, H5F_ACC_RDONLY, old_ff_fapl_id)) < 0)
-        TEST_ERROR;
+        /* Restore the default error handler (set in h5_reset()) */
+        h5_restore_err();
 
-    /* When filters are disabled, make sure we can't read data from a
-     * dataset that requires a filter plugin.
-     */
-    nerrors += (test_no_read_when_plugins_disabled(fid) < 0  ? 1 : 0);
+        /*******************************************************************/
+        /* ENSURE THAT DISABLING FILTER PLUGINS VIA THE FILTER FLAGS WORKS */
+        /*******************************************************************/
 
-    if (H5Fclose(fid) < 0)
-        TEST_ERROR;
+        /* Close the library so that all loaded plugin libraries are unloaded */
+        h5_reset();
+        if ((old_ff_fapl_id = h5_fileaccess()) < 0)
+            TEST_ERROR;
+
+        /* Set the FAPL for the type of format */
+        if (new_format) {
+            /* Copy the file access property list and set the latest file format on it */
+            if ((new_ff_fapl_id = H5Pcopy(old_ff_fapl_id)) < 0)
+                TEST_ERROR;
+            if (H5Pset_libver_bounds(new_ff_fapl_id, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+                TEST_ERROR;
+
+            my_fapl_id = new_ff_fapl_id;
+        }
+        else
+            my_fapl_id = old_ff_fapl_id;
+
+        /* Reopen the file for testing data reading */
+        if ((fid = H5Fopen(filename, H5F_ACC_RDONLY, my_fapl_id)) < 0)
+            TEST_ERROR;
+
+        /* When filters are disabled, make sure we can't read data from a
+        * dataset that requires a filter plugin.
+        */
+        nerrors += (test_no_read_when_plugins_disabled(fid) < 0  ? 1 : 0);
+
+        if (H5Fclose(fid) < 0)
+            TEST_ERROR;
+
+        /*********************/
+        /* CLEAN UP          */
+        /*********************/
+        /* Close FAPLs */
+        if (new_format) {
+            if (H5Pclose(new_ff_fapl_id) < 0)
+                TEST_ERROR;
+        }
+        else {
+            /* Restore the default error handler (set in h5_reset()) */
+            h5_restore_err();
+
+            if (H5Pclose(old_ff_fapl_id) < 0)
+                TEST_ERROR;
+        }
+
+        /* Free up saved arrays */
+        free_2D_array(&orig_deflate_g);
+        free_2D_array(&orig_dynlib1_g);
+        free_2D_array(&orig_dynlib2_g);
+        free_2D_array(&orig_dynlib4_g);
+    } /* end for */
+
+    h5_cleanup(FILENAME, old_ff_fapl_id);
 
     /************************************/
     /* TEST THE FILTER PLUGIN API CALLS */
@@ -1473,21 +1532,10 @@ main(void)
     /* Test the APIs for access to the filter plugin path table */
     nerrors += (test_path_api_calls() < 0  ? 1 : 0);
 
-    /*********************/
-    /* CLEAN UP AND EXIT */
-    /*********************/
-
-    /* Free up saved arrays */
-    free_2D_array(&orig_deflate_g);
-    free_2D_array(&orig_dynlib1_g);
-    free_2D_array(&orig_dynlib2_g);
-    free_2D_array(&orig_dynlib4_g);
-
     if (nerrors)
         TEST_ERROR;
 
     HDprintf("All plugin tests passed.\n");
-    h5_cleanup(FILENAME, old_ff_fapl_id);
 
     HDexit(EXIT_SUCCESS);
 
diff --git a/test/vds.c b/test/vds.c
index 10da0de..7d55c37 100644
--- a/test/vds.c
+++ b/test/vds.c
@@ -36,6 +36,12 @@ const char *FILENAME[] = {
     "vds_src_1",
     "vds%%_src",
     "vds_dapl",
+    "vds_virt_2",
+    "vds_virt_3",
+    "vds_src_2",
+    "vds_src_3",
+    "vds%%_src2",
+    "vds_dapl2",
     NULL
 };
 
@@ -49,6 +55,8 @@ const char *FILENAME[] = {
 
 #define FILENAME_BUF_SIZE       1024
 
+#define TMPDIR          "tmp/"
+
 
 /*-------------------------------------------------------------------------
  * Function:    vds_select_equal
@@ -1110,6 +1118,449 @@ error:
      return 1;
 } /* end test_api() */
 
+/*-------------------------------------------------------------------------
+ * Function:    vds_link_prefix
+ *
+ * Purpose:     Set up vds link prefix via H5Pset_virtual_prefix() to be "tmp"
+ *        Should be able to access the target source files in tmp directory via the prefix set
+ *        by H5Pset_virtual_prefix()
+ *
+ * Return:      Success:        0
+ *              Failure:        -1
+ *-------------------------------------------------------------------------
+ */
+static int
+test_vds_prefix(unsigned config, hid_t fapl)
+{
+    char        srcfilename[FILENAME_BUF_SIZE];
+    char        srcfilename_map[FILENAME_BUF_SIZE];
+    char        vfilename[FILENAME_BUF_SIZE];
+    char        vfilename2[FILENAME_BUF_SIZE];
+    char        srcfilenamepct[FILENAME_BUF_SIZE];
+    char        srcfilenamepct_map[FILENAME_BUF_SIZE];
+    const char *srcfilenamepct_map_orig = "vds%%%%_src";
+    hid_t       srcfile[4] = {-1, -1, -1, -1}; /* Files with source dsets */
+    hid_t       vfile = -1;     /* File with virtual dset */
+    hid_t       vfile2 = -1;    /* File with copied virtual dset */
+    hid_t       dcpl = -1;      /* Dataset creation property list */
+    hid_t       dapl = -1;      /* Dataset access property list */
+    hid_t       srcspace[4] = {-1, -1, -1, -1}; /* Source dataspaces */
+    hid_t       vspace[4] = {-1, -1, -1, -1}; /* Virtual dset dataspaces */
+    hid_t       memspace = -1;  /* Memory dataspace */
+    hid_t       srcdset[4] = {-1, -1, -1, -1}; /* Source datsets */
+    hid_t       vdset = -1;     /* Virtual dataset */
+    hsize_t     dims[4] = {10, 26, 0, 0}; /* Data space current size */
+    hsize_t     start[4];       /* Hyperslab start */
+    hsize_t     stride[4];      /* Hyperslab stride */
+    hsize_t     count[4];       /* Hyperslab count */
+    hsize_t     block[4];       /* Hyperslab block */
+    hssize_t    offset[2] = {0, 0}; /* Selection offset */
+    int         buf[10][26];    /* Write and expected read buffer */
+    int         rbuf[10][26];   /* Read buffer */
+    int         rbuf99[9][9];   /* 9x9 Read buffer */
+    int         evbuf[10][26];  /* Expected VDS "buffer" */
+    int         erbuf[10][26];  /* Expected read buffer */
+    int         fill = -1;      /* Fill value */
+    herr_t      ret;            /* Generic return value */
+    int         i, j;
+    char        buffer[1024];   /* buffer to read vds_prefix       */
+
+    TESTING("basic virtual dataset I/O via H5Pset_vds_prefix()")
+
+    h5_fixname(FILENAME[0], fapl, vfilename, sizeof vfilename);
+    h5_fixname(FILENAME[7], fapl, vfilename2, sizeof vfilename2);
+    h5_fixname(FILENAME[8], fapl, srcfilename, sizeof srcfilename);
+    h5_fixname_printf(FILENAME[8], fapl, srcfilename_map, sizeof srcfilename_map);
+    h5_fixname(FILENAME[10], fapl, srcfilenamepct, sizeof srcfilenamepct);
+    h5_fixname_printf(srcfilenamepct_map_orig, fapl, srcfilenamepct_map, sizeof srcfilenamepct_map);
+
+    /* create tmp directory and get current working directory path */
+    if (HDmkdir(TMPDIR, (mode_t)0755) < 0 && errno != EEXIST)
+        TEST_ERROR
+
+    /* Create DCPL */
+    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        TEST_ERROR
+
+    /* Set fill value */
+    if(H5Pset_fill_value(dcpl, H5T_NATIVE_INT, &fill) < 0)
+        TEST_ERROR
+
+    /* Initialize VDS prefix items */
+    if((dapl = H5Pcreate(H5P_DATASET_ACCESS)) < 0)
+        TEST_ERROR
+
+    if(H5Pset_virtual_prefix(dapl, TMPDIR) < 0)
+        TEST_ERROR
+    if(H5Pget_virtual_prefix(dapl, buffer, sizeof(buffer)) < 0)
+        TEST_ERROR
+
+    if(HDstrcmp(buffer, TMPDIR) != 0)
+        FAIL_PUTS_ERROR("vds prefix not set correctly");
+
+    /*
+     * Test 1: All - all selection
+     */
+    /* Create source dataspace */
+    if((srcspace[0] = H5Screate_simple(2, dims, NULL)) < 0)
+        TEST_ERROR
+
+    /* Create virtual dataspace */
+    if((vspace[0] = H5Screate_simple(2, dims, NULL)) < 0)
+        TEST_ERROR
+
+    /* Select all (should not be necessary, but just to be sure) */
+    if(H5Sselect_all(srcspace[0]) < 0)
+        TEST_ERROR
+    if(H5Sselect_all(vspace[0]) < 0)
+        TEST_ERROR
+
+    /* Add virtual layout mapping */
+    if(H5Pset_virtual(dcpl, vspace[0], config & TEST_IO_DIFFERENT_FILE ? srcfilename_map : ".", "src_dset", srcspace[0]) < 0)
+        TEST_ERROR
+
+    /* Create virtual file */
+    if((vfile = H5Fcreate(vfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+        TEST_ERROR
+
+    /* Create source file if requested */
+    if(config & TEST_IO_DIFFERENT_FILE) {
+        HDgetcwd(buffer, 1024);
+        HDchdir(TMPDIR);
+        if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+        HDchdir(buffer);
+    }
+    else {
+        srcfile[0] = vfile;
+        if(H5Iinc_ref(srcfile[0]) < 0)
+            TEST_ERROR
+    }
+
+    /* Create source dataset */
+    if((srcdset[0] = H5Dcreate2(srcfile[0], "src_dset", H5T_NATIVE_INT, srcspace[0], H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        TEST_ERROR
+
+    /* Create virtual dataset */
+    if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
+        TEST_ERROR
+
+    /* Populate write buffer */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            buf[i][j] = (i * (int)(sizeof(buf[0]) / sizeof(buf[0][0]))) + j;
+
+    /* Write data directly to source dataset */
+    if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+        TEST_ERROR
+
+    /* Close srcdset and srcfile if config option specified */
+    if(config & TEST_IO_CLOSE_SRC) {
+        if(H5Dclose(srcdset[0]) < 0)
+            TEST_ERROR
+        srcdset[0] = -1;
+
+        if(config & TEST_IO_DIFFERENT_FILE) {
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+        }
+    }
+
+    /* Reopen virtual dataset and file if config option specified */
+    if(config & TEST_IO_REOPEN_VIRT) {
+        if(H5Dclose(vdset) < 0)
+            TEST_ERROR
+        vdset = -1;
+        if(H5Fclose(vfile) < 0)
+            TEST_ERROR
+        vfile = -1;
+        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, fapl)) < 0)
+            TEST_ERROR
+        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+            TEST_ERROR
+    }
+
+    /* Read data through virtual dataset */
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
+    if(H5Dread(vdset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+        TEST_ERROR
+
+    /* Verify read data */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++) {
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            if(rbuf[i][j] != buf[i][j]) {
+                TEST_ERROR
+            }
+    }
+
+    /* Adjust write buffer */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            buf[i][j] += (int)(sizeof(buf) / sizeof(buf[0][0]));
+
+    /* Write data through virtual dataset */
+    if(H5Dwrite(vdset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+        TEST_ERROR
+
+    /* Reopen srcdset and srcfile if config option specified */
+    if(config & TEST_IO_CLOSE_SRC) {
+        if(config & TEST_IO_DIFFERENT_FILE) {
+            HDgetcwd(buffer, 1024);
+            HDchdir(TMPDIR);
+            if((srcfile[0] = H5Fopen(srcfilename, H5F_ACC_RDONLY, fapl)) < 0)
+                TEST_ERROR
+            HDchdir(buffer);
+        }
+        if((srcdset[0] = H5Dopen2(srcfile[0], "src_dset", H5P_DEFAULT)) < 0)
+            TEST_ERROR
+    }
+
+    /* Read data directly from source dataset */
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
+    if(H5Dread(srcdset[0], H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+        TEST_ERROR
+
+    /* Verify read data */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            if(rbuf[i][j] != buf[i][j])
+                TEST_ERROR
+
+    /* Close */
+    if(H5Dclose(srcdset[0]) < 0)
+        TEST_ERROR
+    srcdset[0] = -1;
+    if(H5Dclose(vdset) < 0)
+        TEST_ERROR
+    vdset = -1;
+    if(H5Fclose(srcfile[0]) < 0)
+        TEST_ERROR
+    srcfile[0] = -1;
+    if(H5Fclose(vfile) < 0)
+        TEST_ERROR
+    vfile = -1;
+    if(H5Sclose(srcspace[0]) < 0)
+        TEST_ERROR
+    srcspace[0] = -1;
+    if(H5Sclose(vspace[0]) < 0)
+        TEST_ERROR
+    vspace[0] = -1;
+    if(H5Pclose(dapl) < 0)
+        TEST_ERROR
+    dapl = -1;
+    if(H5Pclose(dcpl) < 0)
+        TEST_ERROR
+    dcpl = -1;
+
+    /*
+     * Test 2: All - all selection with ENV prefix
+     */
+    if(HDsetenv("HDF5_VDS_PREFIX", "${ORIGIN}/tmp", 1))
+        TEST_ERROR
+
+    /* Create DCPL */
+    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        TEST_ERROR
+
+    /* Set fill value */
+    if(H5Pset_fill_value(dcpl, H5T_NATIVE_INT, &fill) < 0)
+        TEST_ERROR
+
+    /* Set prefix to a nonexistent directory, will be overwritten by environment variable */
+    if((dapl = H5Pcreate(H5P_DATASET_ACCESS)) < 0)
+        TEST_ERROR
+
+    if(H5Pset_virtual_prefix(dapl, "someprefix") < 0)
+        TEST_ERROR
+    if(H5Pget_virtual_prefix(dapl, buffer, sizeof(buffer)) < 0)
+        TEST_ERROR
+
+    if(HDstrcmp(buffer, "someprefix") != 0)
+        FAIL_PUTS_ERROR("vds prefix not set correctly");
+
+    /* Create source dataspace */
+    if((srcspace[0] = H5Screate_simple(2, dims, NULL)) < 0)
+        TEST_ERROR
+
+    /* Create virtual dataspace */
+    if((vspace[0] = H5Screate_simple(2, dims, NULL)) < 0)
+        TEST_ERROR
+
+    /* Select all (should not be necessary, but just to be sure) */
+    if(H5Sselect_all(srcspace[0]) < 0)
+        TEST_ERROR
+    if(H5Sselect_all(vspace[0]) < 0)
+        TEST_ERROR
+
+    /* Add virtual layout mapping */
+    if(H5Pset_virtual(dcpl, vspace[0], config & TEST_IO_DIFFERENT_FILE ? srcfilename_map : ".", "src_dset", srcspace[0]) < 0)
+        TEST_ERROR
+
+    /* Create virtual file */
+    if((vfile = H5Fcreate(vfilename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+        TEST_ERROR
+
+    /* Create source file if requested */
+    if(config & TEST_IO_DIFFERENT_FILE) {
+        HDgetcwd(buffer, 1024);
+        HDchdir(TMPDIR);
+        if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+        HDchdir(buffer);
+    }
+    else {
+        srcfile[0] = vfile;
+        if(H5Iinc_ref(srcfile[0]) < 0)
+            TEST_ERROR
+    }
+
+    /* Create source dataset */
+    if((srcdset[0] = H5Dcreate2(srcfile[0], "src_dset", H5T_NATIVE_INT, srcspace[0], H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        TEST_ERROR
+
+    /* Create virtual dataset */
+    if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
+        TEST_ERROR
+
+    /* Populate write buffer */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            buf[i][j] = (i * (int)(sizeof(buf[0]) / sizeof(buf[0][0]))) + j;
+
+    /* Write data directly to source dataset */
+    if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+        TEST_ERROR
+
+    /* Close srcdset and srcfile if config option specified */
+    if(config & TEST_IO_CLOSE_SRC) {
+        if(H5Dclose(srcdset[0]) < 0)
+            TEST_ERROR
+        srcdset[0] = -1;
+
+        if(config & TEST_IO_DIFFERENT_FILE) {
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+        }
+    }
+
+    /* Reopen virtual dataset and file if config option specified */
+    if(config & TEST_IO_REOPEN_VIRT) {
+        if(H5Dclose(vdset) < 0)
+            TEST_ERROR
+        vdset = -1;
+        if(H5Fclose(vfile) < 0)
+            TEST_ERROR
+        vfile = -1;
+        if((vfile = H5Fopen(vfilename2, H5F_ACC_RDWR, fapl)) < 0)
+            TEST_ERROR
+        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+            TEST_ERROR
+    }
+
+    /* Read data through virtual dataset */
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
+    if(H5Dread(vdset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+        TEST_ERROR
+
+    /* Verify read data */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++) {
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            if(rbuf[i][j] != buf[i][j]) {
+                TEST_ERROR
+            }
+    }
+
+    /* Adjust write buffer */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            buf[i][j] += (int)(sizeof(buf) / sizeof(buf[0][0]));
+
+    /* Write data through virtual dataset */
+    if(H5Dwrite(vdset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+        TEST_ERROR
+
+    /* Reopen srcdset and srcfile if config option specified */
+    if(config & TEST_IO_CLOSE_SRC) {
+        if(config & TEST_IO_DIFFERENT_FILE) {
+            HDgetcwd(buffer, 1024);
+            HDchdir(TMPDIR);
+            if((srcfile[0] = H5Fopen(srcfilename, H5F_ACC_RDONLY, fapl)) < 0)
+                TEST_ERROR
+            HDchdir(buffer);
+        }
+        if((srcdset[0] = H5Dopen2(srcfile[0], "src_dset", H5P_DEFAULT)) < 0)
+            TEST_ERROR
+    }
+
+    /* Read data directly from source dataset */
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
+    if(H5Dread(srcdset[0], H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+        TEST_ERROR
+
+    /* Verify read data */
+    for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
+        for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
+            if(rbuf[i][j] != buf[i][j])
+                TEST_ERROR
+
+    /* Close */
+    if(H5Dclose(vdset) < 0)
+        TEST_ERROR
+    vdset = -1;
+    if(H5Dclose(srcdset[0]) < 0)
+        TEST_ERROR
+    srcdset[0] = -1;
+    if(H5Fclose(srcfile[0]) < 0)
+        TEST_ERROR
+    srcfile[0] = -1;
+    if(H5Fclose(vfile) < 0)
+        TEST_ERROR
+    vfile = -1;
+    if(H5Sclose(srcspace[0]) < 0)
+        TEST_ERROR
+    srcspace[0] = -1;
+    if(H5Sclose(vspace[0]) < 0)
+        TEST_ERROR
+    vspace[0] = -1;
+    if(H5Pclose(dapl) < 0)
+        TEST_ERROR
+    dapl = -1;
+    if(H5Pclose(dcpl) < 0)
+        TEST_ERROR
+    dcpl = -1;
+
+    if(HDsetenv("HDF5_VDS_PREFIX", "", 1) < 0)
+        TEST_ERROR
+
+    PASSED();
+    return 0;
+
+ error:
+    H5E_BEGIN_TRY {
+        for(i = 0; i < (int)(sizeof(srcdset) / sizeof(srcdset[0])); i++)
+            H5Dclose(srcdset[i]);
+        H5Dclose(vdset);
+        for(i = 0; i < (int)(sizeof(srcfile) / sizeof(srcfile[0])); i++)
+            H5Fclose(srcfile[i]);
+        H5Fclose(vfile);
+        H5Fclose(vfile2);
+        for(i = 0; i < (int)(sizeof(srcspace) / sizeof(srcspace[0])); i++)
+            H5Sclose(srcspace[i]);
+        for(i = 0; i < (int)(sizeof(vspace) / sizeof(vspace[0])); i++)
+            H5Sclose(vspace[i]);
+        H5Sclose(memspace);
+        H5Pclose(dapl);
+        H5Pclose(dcpl);
+    } H5E_END_TRY;
+
+    if(HDsetenv("HDF5_VDS_PREFIX", "", 1) < 0)
+        TEST_ERROR
+
+    return 1;
+} /* end vds_link_prefix() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    test_basic_io
@@ -11179,6 +11630,7 @@ main(void)
     for(bit_config = 0; bit_config < TEST_IO_NTESTS; bit_config++) {
         printf("Config: %s%s%s\n", bit_config & TEST_IO_CLOSE_SRC ? "closed source dataset, " : "", bit_config & TEST_IO_DIFFERENT_FILE ? "different source file" : "same source file", bit_config & TEST_IO_REOPEN_VIRT ? ", reopen virtual file" : "");
         nerrors += test_basic_io(bit_config, fapl);
+        nerrors += test_vds_prefix(bit_config, fapl);
         nerrors += test_unlim(bit_config, fapl);
         nerrors += test_printf(bit_config, fapl);
         nerrors += test_all(bit_config, fapl);