Implement support for big I/O for independent reads (#1446)

* Implement big I/O support for independent reads. Add test for this.

* Committing clang-format changes

* Update big I/O code in H5FD__mpio_write() to match that in
H5FD__mpio_read().

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

2 files changed, 64 insertions, 23 deletions

diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 1feff43..1969899 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -1172,6 +1172,7 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
     int n;
 #endif
     hbool_t use_view_this_time = FALSE;
+    hbool_t derived_type       = FALSE;
     hbool_t rank0_bcast        = FALSE; /* If read-with-rank0-and-bcast flag was used */
 #ifdef H5FDmpio_DEBUG
     hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
@@ -1199,8 +1200,6 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
     if (H5FD_mpi_haddr_to_MPIOff(addr, &mpi_off /*out*/) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_BADRANGE, FAIL, "can't convert from haddr to MPI off")
     size_i = (int)size;
-    if ((hsize_t)size_i != size)
-        HGOTO_ERROR(H5E_INTERNAL, H5E_BADRANGE, FAIL, "can't convert from size to size_i")
 
     /* Only look for MPI views for raw data transfers */
     if (type == H5FD_MEM_DRAW) {
@@ -1304,6 +1303,21 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
             HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
     } /* end if */
     else {
+        if (size != (hsize_t)size_i) {
+            /* If HERE, then we need to work around the integer size limit
+             * of 2GB. The input size_t size variable cannot fit into an integer,
+             * but we can get around that limitation by creating a different datatype
+             * and then setting the integer size (or element count) to 1 when using
+             * the derived_type.
+             */
+
+            if (H5_mpio_create_large_type(size, 0, MPI_BYTE, &buf_type) < 0)
+                HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "can't create MPI-I/O datatype")
+
+            derived_type = TRUE;
+            size_i       = 1;
+        }
+
 #ifdef H5FDmpio_DEBUG
         if (H5FD_mpio_debug_r_flag)
             HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", __func__, file->mpi_rank);
@@ -1377,6 +1391,9 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
         HDmemset((char *)buf + bytes_read, 0, (size_t)n);
 
 done:
+    if (derived_type)
+        MPI_Type_free(&buf_type);
+
 #ifdef H5FDmpio_DEBUG
     if (H5FD_mpio_debug_t_flag)
         HDfprintf(stderr, "%s: (%d) Leaving\n", __func__, file->mpi_rank);
@@ -1489,20 +1506,6 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
          */
         mpi_off = 0;
     } /* end if */
-    else if (size != (hsize_t)size_i) {
-        /* If HERE, then we need to work around the integer size limit
-         * of 2GB. The input size_t size variable cannot fit into an integer,
-         * but we can get around that limitation by creating a different datatype
-         * and then setting the integer size (or element count) to 1 when using
-         * the derived_type.
-         */
-
-        if (H5_mpio_create_large_type(size, 0, MPI_BYTE, &buf_type) < 0)
-            HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "can't create MPI-I/O datatype")
-
-        derived_type = TRUE;
-        size_i       = 1;
-    }
 
     /* Write the data. */
     if (use_view_this_time) {
@@ -1548,6 +1551,21 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
             HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
     } /* end if */
     else {
+        if (size != (hsize_t)size_i) {
+            /* If HERE, then we need to work around the integer size limit
+             * of 2GB. The input size_t size variable cannot fit into an integer,
+             * but we can get around that limitation by creating a different datatype
+             * and then setting the integer size (or element count) to 1 when using
+             * the derived_type.
+             */
+
+            if (H5_mpio_create_large_type(size, 0, MPI_BYTE, &buf_type) < 0)
+                HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "can't create MPI-I/O datatype")
+
+            derived_type = TRUE;
+            size_i       = 1;
+        }
+
 #ifdef H5FDmpio_DEBUG
         if (H5FD_mpio_debug_w_flag)
             HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", __func__, file->mpi_rank);
diff --git a/testpar/t_bigio.c b/testpar/t_bigio.c
index 4df624b..0a971c5 100644
--- a/testpar/t_bigio.c
+++ b/testpar/t_bigio.c
@@ -1107,13 +1107,15 @@ single_rank_independent_io(void)
         HDprintf("\nSingle Rank Independent I/O\n");
 
     if (MAIN_PROCESS) {
-        hsize_t dims[]    = {LARGE_DIM};
-        hid_t   file_id   = -1;
-        hid_t   fapl_id   = -1;
-        hid_t   dset_id   = -1;
-        hid_t   fspace_id = -1;
-        hid_t   mspace_id = -1;
-        void *  data      = NULL;
+        hsize_t  dims[]    = {LARGE_DIM};
+        hid_t    file_id   = -1;
+        hid_t    fapl_id   = -1;
+        hid_t    dset_id   = -1;
+        hid_t    fspace_id = -1;
+        hid_t    mspace_id = -1;
+        herr_t   ret;
+        int *    data = NULL;
+        uint64_t i;
 
         fapl_id = H5Pcreate(H5P_FILE_ACCESS);
         VRFY_G((fapl_id >= 0), "H5P_FILE_ACCESS");
@@ -1135,6 +1137,10 @@ single_rank_independent_io(void)
 
         data = malloc(LARGE_DIM * sizeof(int));
 
+        /* Initialize data */
+        for (i = 0; i < LARGE_DIM; i++)
+            data[i] = (int)(i % (uint64_t)DXFER_BIGCOUNT);
+
         if (mpi_rank_g == 0)
             H5Sselect_all(fspace_id);
         else
@@ -1143,7 +1149,24 @@ single_rank_independent_io(void)
         dims[0]   = LARGE_DIM;
         mspace_id = H5Screate_simple(1, dims, NULL);
         VRFY_G((mspace_id >= 0), "H5Screate_simple mspace_id succeeded");
+
+        /* Write data */
         H5Dwrite(dset_id, H5T_NATIVE_INT, mspace_id, fspace_id, H5P_DEFAULT, data);
+        VRFY_G((ret >= 0), "H5Dwrite succeeded");
+
+        /* Wipe buffer */
+        HDmemset(data, 0, LARGE_DIM * sizeof(int));
+
+        /* Read data back */
+        H5Dread(dset_id, H5T_NATIVE_INT, mspace_id, fspace_id, H5P_DEFAULT, data);
+        VRFY_G((ret >= 0), "H5Dread succeeded");
+
+        /* Verify data */
+        for (i = 0; i < LARGE_DIM; i++)
+            if (data[i] != (int)(i % (uint64_t)DXFER_BIGCOUNT)) {
+                HDfprintf(stderr, "verify failed\n");
+                exit(1);
+            }
 
         free(data);
         H5Sclose(mspace_id);