Multi Dataset (#2120)

* Fix bug with cross platform compatibility of references within vlens.
No testing yet.

* Merge from multi_rd_wd_coll_io to a more recent branch from develop.
Untested, probably does not work yet.

* Committing clang-format changes

* Committing clang-format changes

* Fix many bugs in multi dataset branch.  Mostly works, some issues in
SWMR tests.

* Committing clang-format changes

* Disable test in swmr.c that was failing due to bug in HDF5 unrelated to
multi dataset.

* Committing clang-format changes

* Fixed fortran multi-dataset tests

* Fixed xlf errors

* Added benchmark code for multi-datasets

* loops over datasets

* added missing error arg.

* Added gnuplot formatting

* Jonathan Kim original MD benchmarking code

* updated MD benchmarking code

* code clean-up

* Only make files in feature test mode

* misc clean-up

* removed TEST_MDSET_NO_LAST_DSET_2ND_PROC option

* Committing clang-format changes

* Change multi dataset API to use arrays of individual parameters instead
of the parameter struct.

* Committing clang-format changes

* Update to new multi dataset Fortran API and tests. (#1724)

* Update to new multi dataset Fortran API and tests.
* Sync Fortran with develop.
* skipping h5pget_mpio_actual_io_mode_f for now

* Fixed issue with dxpl_id, changed to variable size dim. (#1770)

* Remove "is_coll_broken" field from H5D_io_info_t struct

* Committing clang-format changes

* Minor cleanup in multi dataset code.

* Committing clang-format changes

* Clean up in multi dataset code.

* Committing clang-format changes

* Committing clang-format changes

* Fix speeling

* Fix bug in parallel compression. Switch base_maddr in io_info to be a
union.

* Committing clang-format changes

* Implement selection I/O support with multi dataset.  Will be broken in
parallel until PR 1803 is merged to develop then the MDS branch.

* Committing clang-format changes

* Spelling

* Fix bug in multi dataset that could cause errors when only some of the
datasets in the multi dataset I/O used type conversion.

* Committing clang-format changes

* Integrate multi dataset APIs with VOL layer.  Add async versions of
multi dataset APIs.

* Committing clang-format changes

* Spelling fixes

* Fix bug in non-parallel HDF5 compilation.

* Committing clang-format changes

* Fix potential memory/free list error. Minor performance fix. Other minor
changes.

* Committing clang-format changes

* Fix memory leak with memory dataspace for I/O.

* Committing clang-format changes

* Fix stack variables too large.  Rename H5D_dset_info_t to
H5D_dset_io_info_t.

* Committing clang-format changes

* Remove mem_space_alloc field from H5D_dset_io_info_t.  Each function is
now responsible for freeing any spaces it adds to dset_info.

* Committing clang-format changes

* fixed _multi Fortran declaration

* Refactor various things in (mostly) the serial I/O code path to make
things more maintainable.

* Committing clang-format changes

* updated to array based, doxygen, and examples

* Reinstate H5D_chunk_map_t, stored (via pointer) inside
H5D_dset_io_info_t.

* Change from calloc to malloc for H5D_dset_io_info_t and H5D_chunk_map_t.
Switch temporary dset_infos to be local stack variables.

* Committing clang-format changes

* format cleanup

* format cleanup

* added coll and ind

* Modify all parallel I/O paths to take dset_info instead of assuming
dset_info[0].

* Committing clang-format changes

* fixed output

* Rework parallel I/O code to work properly with multi dataset in more
cases.  Fix bug in parallel compression.

* Committing clang-format changes

* Prevent H5D__multi_chunk_collective_io() from messing up collective opt
property for other datasets in I/O.  Other minor cleanup.  Add new test
case to t_pmulti_dset.c for H5FD_MPIO_INDIVIDUAL_IO, disabled for now
due to failures apparently unrelated to multi dataset code.

* Fix spelling

* Committing clang-format changes

* Replace N log N algorithm for finding chunk in
H5D__multi_chunk_collective_io() with O(N) algorithm, and remove use of
io_info->sel_pieces in that function.

* Committing clang-format changes

* Replace sel_pieces skiplist in io_info with flat array of pointers, use
qsort in I/O routine only when necessary.

* Committing clang-format changes

* Add new test case to mdset.c

* Committing clang-format changes

* Fix spelling

* Very minor fix in H5VL__native_dataset_read()

* Fix bug that could affect filtered parallel multi-dataset I/O.

* Add RM entries for H5Dread_multi(), H5Dread_multi_async(),
H5Dwrite_multi(), and H5Dwrite_multi_async()

* Unskip test in swmr.c

* Committing clang-format changes

* Eliminate H5D__pre_read and H5D__pre_write

* Remove examples/ph5mdsettest.c. Will fix and re-add as a test.

* Enable hyperslab combinations in mdset test

* Committing clang-format changes

* Clarify H5Dread/write_multi documentation.

* Fix bugs in multi-dataset I/O.  Expand serial multi dataset test.
Update macro in parallel multi dataset test.

* Committing clang-format changes

* Spelling

* Remove obsolete entry in bin/trace

* Rework type conversion buffer allocation. Only one buffer is shared
between datasets in mdset mode, and it is malloced instead of calloced.

* Committing clang-format changes

* Fix bug in error handling in H5D__read/write

* added multi-dataset fortran check with optional dataset creation id (#2150)

* removed dup. dll entry

* Address comments from code review.

* Remove spurious changes in H5Fmpi.c

* Fix issue with reading unallocated datasets in multi-dataset mode.
Address other comments from code review.

* Committing clang-format changes

* Delay chunk index lookup from io_init to mdio_init so it doesn't add
overhead to single dataset I/O.

* Committing clang-format changes

* Fix inappropriate use of piece_count

* updated copyright on new file, removed benchmark from testing dir.

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: M. Scot Breitenfeld <brtnfld@hdfgroup.org>
Co-authored-by: Dana Robinson <43805+derobins@users.noreply.github.com>

4 files changed, 718 insertions, 3 deletions

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index b5af95e..a9412f0 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -339,6 +339,7 @@ set (H5_TESTS
     dsets
     chunk_info # compression lib link
     cmpd_dset
+    mdset
     filter_fail
     extend
     direct_chunk # compression lib link
diff --git a/test/Makefile.am b/test/Makefile.am
index d441113..2176222 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -64,7 +64,7 @@ TEST_PROG= testhdf5 \
            cache cache_api cache_image cache_tagging lheap ohdr \
            stab gheap evict_on_close farray earray btree2 fheap \
            accum hyperslab istore bittests dt_arith page_buffer \
-           dtypes dsets chunk_info cmpd_dset cmpd_dtransform filter_fail extend direct_chunk \
+           dtypes dsets chunk_info cmpd_dset mdset cmpd_dtransform filter_fail extend direct_chunk \
            external efc objcopy objcopy_ref links unlink twriteorder big mtime \
            fillval mount \
            flush1 flush2 app_ref enum set_extent ttsafe enc_dec_plist \
@@ -184,7 +184,7 @@ flush2.chkexe_: flush1.chkexe_
 # specifying a file prefix or low-level driver.  Changing the file
 # prefix or low-level driver with environment variables will influence
 # the temporary file name in ways that the makefile is not aware of.
-CHECK_CLEANFILES+=accum.h5 cmpd_dset.h5 compact_dataset.h5 dataset.h5 dset_offset.h5 \
+CHECK_CLEANFILES+=accum.h5 cmpd_dset.h5 mdset.h5 compact_dataset.h5 dataset.h5 dset_offset.h5 \
     max_compact_dataset.h5 simple.h5 set_local.h5 random_chunks.h5 \
     huge_chunks.h5 chunk_cache.h5 big_chunk.h5 chunk_fast.h5 chunk_expand.h5 \
     chunk_fixed.h5 copy_dcpl_newfile.h5 partial_chunks.h5 layout_extend.h5 \
diff --git a/test/mdset.c b/test/mdset.c
new file mode 100644
index 0000000..f1e50e7
--- /dev/null
+++ b/test/mdset.c
@@ -0,0 +1,714 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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 files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Programmer:  Neil Fortner
+ *              March 10, 2014
+ *
+ * Purpose:     Test H5Dwrite_multi() and H5Dread_multi using randomized
+ *              parameters.  Also tests H5Dwrite() and H5Dread() using a similar
+ *              method.
+ */
+
+#include "h5test.h"
+
+#define NAME_BUF_SIZE     1024
+#define MAX_DSETS         6
+#define MAX_DSET_X        10
+#define MAX_DSET_Y        10
+#define MAX_CHUNK_X       4
+#define MAX_CHUNK_Y       4
+#define MAX_HS_X          6
+#define MAX_HS_Y          6
+#define MAX_HS            3
+#define MAX_POINTS        6
+#define OPS_PER_FILE      50
+#define DSET_MAX_NAME_LEN 8
+#define EXT_FILENAME      "mdset_ext.h5"
+#define SOURCE_DS_NAME    "vds_source"
+
+/* Option flags */
+#define MDSET_FLAG_CHUNK     0x01u
+#define MDSET_FLAG_MLAYOUT   0x02u
+#define MDSET_FLAG_SHAPESAME 0x04u
+#define MDSET_FLAG_MDSET     0x08u
+#define MDSET_FLAG_TCONV     0x10u
+#define MDSET_FLAG_FILTER    0x20u
+#define MDSET_ALL_FLAGS                                                                                      \
+    (MDSET_FLAG_CHUNK | MDSET_FLAG_MLAYOUT | MDSET_FLAG_SHAPESAME | MDSET_FLAG_MDSET | MDSET_FLAG_TCONV |    \
+     MDSET_FLAG_FILTER)
+
+const char *FILENAME[] = {"mdset", "mdset1", "mdset2", NULL};
+
+/* Names for datasets */
+char dset_name[MAX_DSETS][DSET_MAX_NAME_LEN];
+
+/* Whether these filters are available */
+htri_t deflate_avail    = FALSE;
+htri_t fletcher32_avail = FALSE;
+
+static int
+test_mdset_location(hid_t fapl_id)
+{
+    hid_t       file_id1, file_id2;
+    herr_t      ret;
+    hid_t       dset_ids[2];
+    hid_t       mem_type_ids[2];
+    hid_t       mem_space_ids[2];
+    hid_t       file_space_ids[2];
+    void       *rbufs[2];
+    const void *wbufs[2];
+    hsize_t     dset_dims[2];
+    int        *buf = NULL;
+    char        filename1[NAME_BUF_SIZE];
+    char        filename2[NAME_BUF_SIZE];
+
+    TESTING("mdset location");
+
+    h5_fixname(FILENAME[1], fapl_id, filename1, sizeof filename1);
+    h5_fixname(FILENAME[2], fapl_id, filename2, sizeof filename2);
+
+    /* Create files */
+    if ((file_id1 = H5Fcreate(filename1, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id)) < 0)
+        TEST_ERROR;
+    if ((file_id2 = H5Fcreate(filename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id)) < 0)
+        TEST_ERROR;
+
+    if (NULL == (buf = (int *)HDcalloc(2 * MAX_DSET_X * MAX_DSET_Y, sizeof(int))))
+        TEST_ERROR;
+
+    /* Generate memory dataspace */
+    dset_dims[0] = MAX_DSET_X;
+    dset_dims[1] = MAX_DSET_Y;
+    if ((file_space_ids[0] = H5Screate_simple(2, dset_dims, NULL)) < 0)
+        TEST_ERROR;
+    if ((file_space_ids[1] = H5Screate_simple(2, dset_dims, NULL)) < 0)
+        TEST_ERROR;
+
+    mem_space_ids[0] = H5S_ALL;
+    mem_space_ids[1] = H5S_ALL;
+
+    mem_type_ids[0] = H5T_NATIVE_UINT;
+    mem_type_ids[1] = H5T_NATIVE_UINT;
+
+    if ((dset_ids[0] = H5Dcreate2(file_id1, dset_name[0], H5T_NATIVE_UINT, file_space_ids[0], H5P_DEFAULT,
+                                  H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+    if ((dset_ids[1] = H5Dcreate2(file_id2, dset_name[1], H5T_NATIVE_UINT, file_space_ids[1], H5P_DEFAULT,
+                                  H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+
+    wbufs[0] = buf;
+    wbufs[1] = buf + (MAX_DSET_X * MAX_DSET_Y);
+
+    H5E_BEGIN_TRY
+    {
+        ret = H5Dwrite_multi(2, dset_ids, mem_type_ids, mem_space_ids, file_space_ids, H5P_DEFAULT, wbufs);
+    }
+    H5E_END_TRY
+
+    if (ret >= 0) {
+        fprintf(stderr, "H5Dmulti_write with datasets in multiple files should fail.\n");
+        TEST_ERROR;
+    }
+
+    rbufs[0] = buf;
+    rbufs[1] = buf + (MAX_DSET_X * MAX_DSET_Y);
+
+    H5E_BEGIN_TRY
+    {
+        ret = H5Dread_multi(2, dset_ids, mem_type_ids, mem_space_ids, file_space_ids, H5P_DEFAULT, rbufs);
+    }
+    H5E_END_TRY
+
+    if (ret >= 0) {
+        fprintf(stderr, "H5Dmulti_read with datasets in multiple files should fail.\n");
+        TEST_ERROR;
+    }
+
+    H5Dclose(dset_ids[0]);
+    H5Sclose(file_space_ids[0]);
+    H5Dclose(dset_ids[1]);
+    H5Sclose(file_space_ids[1]);
+    H5Fclose(file_id1);
+    H5Fclose(file_id2);
+
+    if (buf)
+        free(buf);
+
+    PASSED();
+    return 0;
+
+error:
+    if (buf)
+        free(buf);
+    return -1;
+}
+
+/*-------------------------------------------------------------------------
+ * Function:    test_mdset
+ *
+ * Purpose:     Test randomized I/O using one or more datasets.  Creates a
+ *              file, runs OPS_PER_FILE read or write operations verifying
+ *              that reads return the expected data, then closes the file.
+ *              Runs the test with a new file niter times.
+ *
+ *              The operations can use either hyperslab or point
+ *              selections.  Options are available for chunked or
+ *              contiguous layout, use of multiple datasets and H5D*_multi
+ *              calls, and use of the "shapesame" algorithm code path.  To
+ *              avoid the shapesame path when that option is not set, this
+ *              function simply adds a dimension to the memory buffer in a
+ *              way that the shapesame code is not designed to handle.
+ *
+ * Return:      Number of errors
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, March 10, 2014
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_mdset(size_t niter, unsigned flags, hid_t fapl_id)
+{
+    hid_t       dset_ids[MAX_DSETS];
+    hid_t       mem_type_ids[MAX_DSETS];
+    hid_t       mem_space_ids[MAX_DSETS];
+    hid_t       file_space_ids[MAX_DSETS];
+    void       *rbufs[MAX_DSETS];
+    const void *wbufs[MAX_DSETS];
+    size_t      max_dsets;
+    size_t      buf_size;
+    size_t      ndsets;
+    hid_t       file_id = -1;
+    hid_t       dcpl_id[MAX_DSETS];
+    hsize_t     dset_dims[MAX_DSETS][3];
+    hsize_t     chunk_dims[2];
+    hsize_t     max_dims[2] = {H5S_UNLIMITED, H5S_UNLIMITED};
+    unsigned   *rbuf        = NULL;
+    unsigned   *rbufi[MAX_DSETS][MAX_DSET_X];
+    unsigned   *erbuf = NULL;
+    unsigned   *erbufi[MAX_DSETS][MAX_DSET_X];
+    unsigned   *wbuf = NULL;
+    unsigned   *wbufi[MAX_DSETS][MAX_DSET_X];
+    unsigned   *efbuf = NULL;
+    unsigned   *efbufi[MAX_DSETS][MAX_DSET_X];
+    hbool_t     do_read;
+    hsize_t     start[3];
+    hsize_t     count[3];
+    hsize_t     points[3 * MAX_POINTS];
+    char        filename[NAME_BUF_SIZE];
+    size_t      i, j, k, l, m, n;
+
+    TESTING("random I/O");
+
+    h5_fixname(FILENAME[0], fapl_id, filename, sizeof filename);
+
+    /* Calculate maximum number of datasets */
+    max_dsets = (flags & MDSET_FLAG_MDSET) ? MAX_DSETS : 1;
+
+    /* Calculate buffer size */
+    buf_size = max_dsets * MAX_DSET_X * MAX_DSET_Y * sizeof(unsigned);
+
+    /* Initialize dcpl_id array */
+    for (i = 0; i < max_dsets; i++)
+        dcpl_id[i] = -1;
+
+    /* Allocate buffers */
+    if (NULL == (rbuf = (unsigned *)HDmalloc(buf_size)))
+        TEST_ERROR;
+    if (NULL == (erbuf = (unsigned *)HDmalloc(buf_size)))
+        TEST_ERROR;
+    if (NULL == (wbuf = (unsigned *)HDmalloc(buf_size)))
+        TEST_ERROR;
+    if (NULL == (efbuf = (unsigned *)HDmalloc(buf_size)))
+        TEST_ERROR;
+
+    /* Initialize buffer indices */
+    for (i = 0; i < max_dsets; i++)
+        for (j = 0; j < MAX_DSET_X; j++) {
+            rbufi[i][j]  = rbuf + (i * MAX_DSET_X * MAX_DSET_Y) + (j * MAX_DSET_Y);
+            erbufi[i][j] = erbuf + (i * MAX_DSET_X * MAX_DSET_Y) + (j * MAX_DSET_Y);
+            wbufi[i][j]  = wbuf + (i * MAX_DSET_X * MAX_DSET_Y) + (j * MAX_DSET_Y);
+            efbufi[i][j] = efbuf + (i * MAX_DSET_X * MAX_DSET_Y) + (j * MAX_DSET_Y);
+        } /* end for */
+
+    /* Initialize 3rd dimension information (for tricking library into using
+     * non-"shapesame" code */
+    for (i = 0; i < max_dsets; i++)
+        dset_dims[i][2] = 1;
+    start[2] = 0;
+    count[2] = 1;
+
+    /* Initialize IDs */
+    for (i = 0; i < max_dsets; i++) {
+        dset_ids[i]       = -1;
+        file_space_ids[i] = -1;
+        mem_type_ids[i]   = H5T_NATIVE_UINT;
+        mem_space_ids[i]  = -1;
+    } /* end for */
+
+    /* Generate memory dataspace */
+    dset_dims[0][0] = MAX_DSET_X;
+    dset_dims[0][1] = MAX_DSET_Y;
+    if ((mem_space_ids[0] = H5Screate_simple((flags & MDSET_FLAG_SHAPESAME) ? 2 : 3, dset_dims[0], NULL)) < 0)
+        TEST_ERROR;
+    for (i = 1; i < max_dsets; i++)
+        if ((mem_space_ids[i] = H5Scopy(mem_space_ids[0])) < 0)
+            TEST_ERROR;
+
+    /* Create dcpl 0 */
+    if ((dcpl_id[0] = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        TEST_ERROR;
+
+    /* Set fill time to alloc, and alloc time to early (so we always know
+     * what's in the file) */
+    if (H5Pset_fill_time(dcpl_id[0], H5D_FILL_TIME_ALLOC) < 0)
+        TEST_ERROR;
+    if (H5Pset_alloc_time(dcpl_id[0], H5D_ALLOC_TIME_EARLY) < 0)
+        TEST_ERROR;
+
+    /* Set filters if requested */
+    if (flags & MDSET_FLAG_FILTER) {
+        if (fletcher32_avail)
+            if (H5Pset_fletcher32(dcpl_id[0]) < 0)
+                TEST_ERROR;
+        if (deflate_avail)
+            if (H5Pset_deflate(dcpl_id[0], 1) < 0)
+                TEST_ERROR;
+    }
+
+    /* Copy dcpl 0 to other slots in dcpl_id array */
+    for (i = 1; i < MAX_DSETS; i++)
+        if ((dcpl_id[i] = H5Pcopy(dcpl_id[0])) < 0)
+            TEST_ERROR;
+
+    /* If this is a multi layout run, set up different filters and layouts. Chunked and virtual
+     * datasets will be set every iteration (with different dims), and contiguous is the default, so
+     * no need to set either of those. */
+    if (flags & MDSET_FLAG_MLAYOUT) {
+        /* Set filters on dataset 2 */
+        if (fletcher32_avail)
+            if (H5Pset_fletcher32(dcpl_id[2]) < 0)
+                TEST_ERROR;
+        if (deflate_avail)
+            if (H5Pset_deflate(dcpl_id[2], 1) < 0)
+                TEST_ERROR;
+
+        /* Dataset 3 is compact */
+        if (H5Pset_layout(dcpl_id[3], H5D_COMPACT) < 0)
+            TEST_ERROR;
+
+        /* Dataset 4 is external */
+        if (H5Pset_external(dcpl_id[4], EXT_FILENAME, 0, H5F_UNLIMITED) < 0)
+            TEST_ERROR;
+    }
+
+    for (i = 0; i < niter; i++) {
+        /* Determine number of datasets */
+        ndsets = (flags & MDSET_FLAG_MLAYOUT) ? 6
+                 : (flags & MDSET_FLAG_MDSET) ? (size_t)((size_t)HDrandom() % max_dsets) + 1
+                                              : 1;
+
+        /* Create file */
+        if ((file_id = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id)) < 0)
+            TEST_ERROR;
+
+        /* Create datasets */
+        for (j = 0; j < ndsets; j++) {
+            hid_t source_dset;
+
+            hbool_t use_chunk =
+                (flags & MDSET_FLAG_CHUNK) || ((flags & MDSET_FLAG_MLAYOUT) && (j == 1 || j == 2));
+
+            /* Generate file dataspace */
+            dset_dims[j][0] = (hsize_t)((HDrandom() % MAX_DSET_X) + 1);
+            dset_dims[j][1] = (hsize_t)((HDrandom() % MAX_DSET_Y) + 1);
+            if ((file_space_ids[j] = H5Screate_simple(2, dset_dims[j], use_chunk ? max_dims : NULL)) < 0)
+                TEST_ERROR;
+
+            /* Generate chunk if called for by configuration (multi layout uses chunked for datasets
+             * 1 and 2) */
+            if (use_chunk) {
+                chunk_dims[0] = (hsize_t)((HDrandom() % MAX_CHUNK_X) + 1);
+                chunk_dims[1] = (hsize_t)((HDrandom() % MAX_CHUNK_Y) + 1);
+                if (H5Pset_chunk(dcpl_id[j], 2, chunk_dims) < 0)
+                    TEST_ERROR;
+            } /* end if */
+            else if ((flags & MDSET_FLAG_CHUNK) && j == 5) {
+                /* Dataset 5 is virtual in multi layout case */
+                /* Set to contiguous to clear previous VDS settings */
+                if (H5Pset_layout(dcpl_id[j], H5D_CONTIGUOUS) < 0)
+                    TEST_ERROR;
+
+                /* Set virtual dataset layout, ALL<>ALL mapping */
+                if (H5Pset_virtual(dcpl_id[j], file_space_ids[j], ".", SOURCE_DS_NAME, file_space_ids[j]) < 0)
+                    TEST_ERROR;
+            }
+
+            /* Create dataset */
+            /* If MDSET_FLAG_TCONV is set, use a different datatype with 50% probability, so
+             * some datasets require type conversion and others do not */
+            if ((dset_ids[j] = H5Dcreate2(file_id, dset_name[j],
+                                          (flags & MDSET_FLAG_TCONV && HDrandom() % 2) ? H5T_NATIVE_LONG
+                                                                                       : H5T_NATIVE_UINT,
+                                          file_space_ids[j], H5P_DEFAULT, dcpl_id[j], H5P_DEFAULT)) < 0)
+                TEST_ERROR;
+
+            /* Create virtual source dataset if necessary.  Use dcpl_id[0] for a contiguous dataset
+             */
+            if ((flags & MDSET_FLAG_MLAYOUT) && (j == 6)) {
+                if ((source_dset = H5Dcreate2(file_id, SOURCE_DS_NAME,
+                                              (flags & MDSET_FLAG_TCONV && HDrandom() % 2) ? H5T_NATIVE_LONG
+                                                                                           : H5T_NATIVE_UINT,
+                                              file_space_ids[j], H5P_DEFAULT, dcpl_id[0], H5P_DEFAULT)) < 0)
+                    TEST_ERROR;
+                if (H5Dclose(source_dset) < 0)
+                    TEST_ERROR;
+            }
+        } /* end for */
+
+        /* Initialize read buffer and expected read buffer */
+        (void)HDmemset(rbuf, 0, buf_size);
+        (void)HDmemset(erbuf, 0, buf_size);
+
+        /* Initialize write buffer */
+        for (j = 0; j < max_dsets; j++)
+            for (k = 0; k < MAX_DSET_X; k++)
+                for (l = 0; l < MAX_DSET_Y; l++)
+                    wbufi[j][k][l] = (unsigned)((j * MAX_DSET_X * MAX_DSET_Y) + (k * MAX_DSET_Y) + l);
+
+        /* Initialize expected file buffer */
+        (void)HDmemset(efbuf, 0, buf_size);
+
+        /* Perform read/write operations */
+        for (j = 0; j < OPS_PER_FILE; j++) {
+            /* Decide whether to read or write.  Can't read on the first iteration with external
+             * layout because the write is needed to create the external file. */
+            do_read = (j == 0 && flags & MDSET_FLAG_MLAYOUT) ? FALSE : (hbool_t)(HDrandom() % 2);
+
+            /* Loop over datasets */
+            for (k = 0; k < ndsets; k++) {
+                int sel_type;
+
+                /* Reset selection */
+                if (H5Sselect_none(mem_space_ids[k]) < 0)
+                    TEST_ERROR;
+                if (H5Sselect_none(file_space_ids[k]) < 0)
+                    TEST_ERROR;
+
+                /* Decide whether to do a hyperslab, point, or all selection */
+                sel_type = HDrandom() % 3;
+                if (sel_type == 0) {
+                    /* Hyperslab */
+                    size_t nhs      = (size_t)((HDrandom() % MAX_HS) + 1); /* Number of hyperslabs */
+                    size_t max_hs_x = (MAX_HS_X <= dset_dims[k][0])
+                                          ? MAX_HS_X
+                                          : dset_dims[k][0]; /* Determine maximum hyperslab size in X */
+                    size_t max_hs_y = (MAX_HS_Y <= dset_dims[k][1])
+                                          ? MAX_HS_Y
+                                          : dset_dims[k][1]; /* Determine maximum hyperslab size in Y */
+
+                    for (l = 0; l < nhs; l++) {
+                        /* Generate hyperslab */
+                        count[0] = (hsize_t)(((hsize_t)HDrandom() % max_hs_x) + 1);
+                        count[1] = (hsize_t)(((hsize_t)HDrandom() % max_hs_y) + 1);
+                        start[0] = (count[0] == dset_dims[k][0])
+                                       ? 0
+                                       : (hsize_t)HDrandom() % (dset_dims[k][0] - count[0] + 1);
+                        start[1] = (count[1] == dset_dims[k][1])
+                                       ? 0
+                                       : (hsize_t)HDrandom() % (dset_dims[k][1] - count[1] + 1);
+
+                        /* Select hyperslab */
+                        if (H5Sselect_hyperslab(mem_space_ids[k], H5S_SELECT_OR, start, NULL, count, NULL) <
+                            0)
+                            TEST_ERROR;
+                        if (H5Sselect_hyperslab(file_space_ids[k], H5S_SELECT_OR, start, NULL, count, NULL) <
+                            0)
+                            TEST_ERROR;
+
+                        /* Update expected buffers */
+                        if (do_read) {
+                            for (m = start[0]; m < (start[0] + count[0]); m++)
+                                for (n = start[1]; n < (start[1] + count[1]); n++)
+                                    erbufi[k][m][n] = efbufi[k][m][n];
+                        } /* end if */
+                        else
+                            for (m = start[0]; m < (start[0] + count[0]); m++)
+                                for (n = start[1]; n < (start[1] + count[1]); n++)
+                                    efbufi[k][m][n] = wbufi[k][m][n];
+                    } /* end for */
+                }     /* end if */
+                else if (sel_type == 1) {
+                    /* Point selection */
+                    size_t npoints = (size_t)(((size_t)HDrandom() % MAX_POINTS) + 1); /* Number of points */
+
+                    /* Generate points */
+                    for (l = 0; l < npoints; l++) {
+                        points[2 * l]       = (unsigned)((hsize_t)HDrandom() % dset_dims[k][0]);
+                        points[(2 * l) + 1] = (unsigned)((hsize_t)HDrandom() % dset_dims[k][1]);
+                    } /* end for */
+
+                    /* Select points in file */
+                    if (H5Sselect_elements(file_space_ids[k], H5S_SELECT_APPEND, npoints, points) < 0)
+                        TEST_ERROR;
+
+                    /* Update expected buffers */
+                    if (do_read) {
+                        for (l = 0; l < npoints; l++)
+                            erbufi[k][points[2 * l]][points[(2 * l) + 1]] =
+                                efbufi[k][points[2 * l]][points[(2 * l) + 1]];
+                    } /* end if */
+                    else
+                        for (l = 0; l < npoints; l++)
+                            efbufi[k][points[2 * l]][points[(2 * l) + 1]] =
+                                wbufi[k][points[2 * l]][points[(2 * l) + 1]];
+
+                    /* Convert to 3D for memory selection, if not using
+                     * "shapesame" */
+                    if (!(flags & MDSET_FLAG_SHAPESAME)) {
+                        for (l = npoints - 1; l > 0; l--) {
+                            points[(3 * l) + 2] = 0;
+                            points[(3 * l) + 1] = points[(2 * l) + 1];
+                            points[3 * l]       = points[2 * l];
+                        } /* end for */
+                        points[2] = 0;
+                    } /* end if */
+
+                    /* Select points in memory */
+                    if (H5Sselect_elements(mem_space_ids[k], H5S_SELECT_APPEND, npoints, points) < 0)
+                        TEST_ERROR;
+                } /* end else */
+                else {
+                    /* All selection */
+                    /* Select entire dataset in file */
+                    if (H5Sselect_all(file_space_ids[k]) < 0)
+                        TEST_ERROR;
+
+                    /* Select entire dataset in memory using hyperslab */
+                    start[0] = 0;
+                    start[1] = 0;
+                    count[0] = dset_dims[k][0];
+                    count[1] = dset_dims[k][1];
+                    if (H5Sselect_hyperslab(mem_space_ids[k], H5S_SELECT_SET, start, NULL, count, NULL) < 0)
+                        TEST_ERROR;
+
+                    /* Update expected buffers */
+                    if (do_read) {
+                        for (m = 0; m < dset_dims[k][0]; m++)
+                            for (n = 0; n < dset_dims[k][1]; n++)
+                                erbufi[k][m][n] = efbufi[k][m][n];
+                    } /* end if */
+                    else
+                        for (m = 0; m < dset_dims[k][0]; m++)
+                            for (n = 0; n < dset_dims[k][1]; n++)
+                                efbufi[k][m][n] = wbufi[k][m][n];
+                }
+            } /* end for */
+
+            /* Perform I/O */
+            if (do_read) {
+                if (flags & MDSET_FLAG_MDSET) {
+                    /* Set buffers */
+                    for (k = 0; k < ndsets; k++)
+                        rbufs[k] = rbufi[k][0];
+
+                    /* Read datasets */
+                    if (H5Dread_multi(ndsets, dset_ids, mem_type_ids, mem_space_ids, file_space_ids,
+                                      H5P_DEFAULT, rbufs) < 0)
+                        TEST_ERROR;
+                } /* end if */
+                else
+                    /* Read */
+                    if (H5Dread(dset_ids[0], mem_type_ids[0], mem_space_ids[0], file_space_ids[0],
+                                H5P_DEFAULT, rbuf) < 0)
+                        TEST_ERROR;
+
+                /* Verify data */
+                if (0 != memcmp(rbuf, erbuf, buf_size))
+                    TEST_ERROR;
+            } /* end if */
+            else {
+                if (flags & MDSET_FLAG_MDSET) {
+                    /* Set buffers */
+                    for (k = 0; k < ndsets; k++)
+                        wbufs[k] = wbufi[k][0];
+
+                    /* Write datasets */
+                    if (H5Dwrite_multi(ndsets, dset_ids, mem_type_ids, mem_space_ids, file_space_ids,
+                                       H5P_DEFAULT, wbufs) < 0)
+                        TEST_ERROR;
+                } /* end if */
+                else
+                    /* Write */
+                    if (H5Dwrite(dset_ids[0], mem_type_ids[0], mem_space_ids[0], file_space_ids[0],
+                                 H5P_DEFAULT, wbuf) < 0)
+                        TEST_ERROR;
+
+                /* Update wbuf */
+                for (l = 0; l < max_dsets; l++)
+                    for (m = 0; m < MAX_DSET_X; m++)
+                        for (n = 0; n < MAX_DSET_Y; n++)
+                            wbufi[l][m][n] += (unsigned)max_dsets * MAX_DSET_X * MAX_DSET_Y;
+            } /* end else */
+        }     /* end for */
+
+        /* Close */
+        for (j = 0; j < ndsets; j++) {
+            if (H5Dclose(dset_ids[j]) < 0)
+                TEST_ERROR;
+            dset_ids[j] = -1;
+            if (H5Sclose(file_space_ids[j]) < 0)
+                TEST_ERROR;
+            file_space_ids[j] = -1;
+        } /* end for */
+        if (H5Fclose(file_id) < 0)
+            TEST_ERROR;
+        file_id = -1;
+
+        /* Cleanup external file.  Need to do this because otherwise there is garbage when the
+         * dataset is created, even with early allocation and fill time. */
+        HDremove(EXT_FILENAME);
+    } /* end for */
+
+    /* Close */
+    for (i = 0; i < max_dsets; i++) {
+        if (H5Sclose(mem_space_ids[i]) < 0)
+            TEST_ERROR;
+        mem_space_ids[i] = -1;
+    } /* end for */
+    for (i = 0; i < MAX_DSETS; i++) {
+        if (H5Pclose(dcpl_id[i]) < 0)
+            TEST_ERROR;
+        dcpl_id[i] = -1;
+    }
+    free(rbuf);
+    rbuf = NULL;
+    free(erbuf);
+    erbuf = NULL;
+    free(wbuf);
+    wbuf = NULL;
+    free(efbuf);
+    efbuf = NULL;
+
+    PASSED();
+
+    return 0;
+
+error:
+    H5E_BEGIN_TRY
+    {
+        for (i = 0; i < max_dsets; i++) {
+            H5Dclose(dset_ids[i]);
+            H5Sclose(mem_space_ids[i]);
+            H5Sclose(file_space_ids[i]);
+            H5Pclose(dcpl_id[i]);
+        } /* end for */
+        H5Fclose(file_id);
+    }
+    H5E_END_TRY
+    if (rbuf)
+        free(rbuf);
+    if (erbuf)
+        free(erbuf);
+    if (wbuf)
+        free(wbuf);
+    if (efbuf)
+        free(efbuf);
+
+    return -1;
+} /* end test_mdset() */
+
+/*-------------------------------------------------------------------------
+ * Function:    main
+ *
+ * Purpose:     Runs all tests with all combinations of configuration
+ *              flags.
+ *
+ * Return:      Success:        0
+ *              Failure:        1
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, March 10, 2014
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(void)
+{
+    hid_t    fapl_id;
+    int      nerrors = 0;
+    unsigned i;
+    int      ret;
+
+    h5_reset();
+    fapl_id = h5_fileaccess();
+
+    /* Initialize random number seed */
+    HDsrandom((unsigned)HDtime(NULL));
+
+    /* Fill dset_name array */
+    for (i = 0; i < MAX_DSETS; i++) {
+        if ((ret = snprintf(dset_name[i], DSET_MAX_NAME_LEN, "dset%u", i)) < 0)
+            TEST_ERROR;
+        if (ret >= DSET_MAX_NAME_LEN)
+            TEST_ERROR;
+    } /* end for */
+
+    /* Check if deflate and fletcher32 filters are available */
+    if ((deflate_avail = H5Zfilter_avail(H5Z_FILTER_DEFLATE)) < 0)
+        TEST_ERROR;
+    if ((fletcher32_avail = H5Zfilter_avail(H5Z_FILTER_FLETCHER32)) < 0)
+        TEST_ERROR;
+
+    for (i = 0; i <= MDSET_ALL_FLAGS; i++) {
+        /* Skip incompatible flag combinations */
+        if (((i & MDSET_FLAG_MLAYOUT) && (i & MDSET_FLAG_CHUNK)) ||
+            ((i & MDSET_FLAG_MLAYOUT) && !(i & MDSET_FLAG_MDSET)) ||
+            ((i & MDSET_FLAG_FILTER) && !(i & MDSET_FLAG_CHUNK)))
+            continue;
+
+        /* Print flag configuration */
+        puts("\nConfiguration:");
+        printf("  Layout:          %s\n", (i & MDSET_FLAG_MLAYOUT) ? "Multi"
+                                          : (i & MDSET_FLAG_CHUNK) ? "Chunked"
+                                                                   : "Contiguous");
+        printf("  Shape same:      %s\n", (i & MDSET_FLAG_SHAPESAME) ? "Yes" : "No");
+        printf("  I/O type:        %s\n", (i & MDSET_FLAG_MDSET) ? "Multi" : "Single");
+        printf("  Type conversion: %s\n", (i & MDSET_FLAG_TCONV) ? "Yes" : "No");
+        printf("  Data filter:     %s\n", (i & MDSET_FLAG_MLAYOUT)  ? "Mixed"
+                                          : (i & MDSET_FLAG_FILTER) ? "Yes"
+                                                                    : "No");
+
+        nerrors += test_mdset(50, i, fapl_id);
+    }
+
+    /* test all datasets in same container */
+    nerrors += test_mdset_location(fapl_id);
+
+    h5_cleanup(FILENAME, fapl_id);
+
+    if (nerrors)
+        goto error;
+    puts("All multi dataset tests passed.");
+
+    return 0;
+
+error:
+    nerrors = MAX(1, nerrors);
+    printf("***** %d multi dataset TEST%s FAILED! *****\n", nerrors, 1 == nerrors ? "" : "S");
+    return 1;
+} /* end main() */
diff --git a/test/testfiles/error_test_1 b/test/testfiles/error_test_1
index 070869e..9798fac 100644
--- a/test/testfiles/error_test_1
+++ b/test/testfiles/error_test_1
@@ -50,7 +50,7 @@ HDF5-DIAG: Error detected in HDF5 (version (number)) thread (IDs):
   #001: (file name) line (number) in H5D__read_api_common(): can't read data
     major: Dataset
     minor: Read failed
-  #002: (file name) line (number) in H5VL_dataset_read(): dataset read failed
+  #002: (file name) line (number) in H5VL_dataset_read_direct(): dataset read failed
     major: Virtual Object Layer
     minor: Read failed
   #003: (file name) line (number) in H5VL__dataset_read(): dataset read failed