Merge pull request #2804 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:final_1_10_prs to hdf5_1_10

* commit '41da55dfe836551936032a33aa7b0acb9d4dc7cb':
  Adds missing HDstrtoumax for S3 VFD
  Merge of develop PRs to 1.10

6 files changed, 158 insertions, 97 deletions

diff --git a/src/H5Dvirtual.c b/src/H5Dvirtual.c
index 6cd6263..0136509 100644
--- a/src/H5Dvirtual.c
+++ b/src/H5Dvirtual.c
@@ -313,6 +313,8 @@ done:
 herr_t
 H5D_virtual_update_min_dims(H5O_layout_t *layout, size_t idx)
 {
+    H5O_storage_virtual_t *virt = &layout->storage.u.virt;
+    H5O_storage_virtual_ent_t *ent = &virt->list[idx];
     H5S_sel_type    sel_type;
     int             rank;
     hsize_t         bounds_start[H5S_MAX_RANK];
@@ -324,10 +326,10 @@ H5D_virtual_update_min_dims(H5O_layout_t *layout, size_t idx)
 
     HDassert(layout);
     HDassert(layout->type == H5D_VIRTUAL);
-    HDassert(idx < layout->storage.u.virt.list_nalloc);
+    HDassert(idx < virt->list_nalloc);
 
     /* Get type of selection */
-    if(H5S_SEL_ERROR == (sel_type = H5S_GET_SELECT_TYPE(layout->storage.u.virt.list[idx].source_dset.virtual_select)))
+    if(H5S_SEL_ERROR == (sel_type = H5S_GET_SELECT_TYPE(ent->source_dset.virtual_select)))
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection type")
 
     /* Do not update min_dims for "all" or "none" selections */
@@ -335,19 +337,19 @@ H5D_virtual_update_min_dims(H5O_layout_t *layout, size_t idx)
         HGOTO_DONE(SUCCEED)
 
     /* Get rank of vspace */
-    if((rank = H5S_GET_EXTENT_NDIMS(layout->storage.u.virt.list[idx].source_dset.virtual_select)) < 0)
+    if((rank = H5S_GET_EXTENT_NDIMS(ent->source_dset.virtual_select)) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get number of dimensions")
 
     /* Get selection bounds */
-    if(H5S_SELECT_BOUNDS(layout->storage.u.virt.list[idx].source_dset.virtual_select, bounds_start, bounds_end) < 0)
+    if(H5S_SELECT_BOUNDS(ent->source_dset.virtual_select, bounds_start, bounds_end) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")
 
     /* Update min_dims */
     for(i = 0; i < rank; i++)
         /* Don't check unlimited dimensions in the selection */
-        if((i != layout->storage.u.virt.list[idx].unlim_dim_virtual)
-                && (bounds_end[i] >= layout->storage.u.virt.min_dims[i]))
-            layout->storage.u.virt.min_dims[i] = bounds_end[i] + (hsize_t)1;
+        if((i != ent->unlim_dim_virtual)
+                && (bounds_end[i] >= virt->min_dims[i]))
+            virt->min_dims[i] = bounds_end[i] + (hsize_t)1;
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -419,6 +421,7 @@ done:
 herr_t
 H5D__virtual_store_layout(H5F_t *f, H5O_layout_t *layout)
 {
+    H5O_storage_virtual_t *virt = &layout->storage.u.virt;
     uint8_t *heap_block = NULL;         /* Block to add to heap */
     size_t *str_size = NULL;            /* Array for VDS entry string lengths */
     uint8_t *heap_block_p;              /* Pointer into the heap block, while encoding */
@@ -433,16 +436,16 @@ H5D__virtual_store_layout(H5F_t *f, H5O_layout_t *layout)
     /* Sanity checking */
     HDassert(f);
     HDassert(layout);
-    HDassert(layout->storage.u.virt.serial_list_hobjid.addr == HADDR_UNDEF);
+    HDassert(virt->serial_list_hobjid.addr == HADDR_UNDEF);
 
     /* Create block if # of used entries > 0 */
-    if(layout->storage.u.virt.list_nused > 0) {
+    if(virt->list_nused > 0) {
 
         /* Set the low/high bounds according to 'f' for the API context */
         H5CX_set_libver_bounds(f);
 
         /* Allocate array for caching results of strlen */
-        if(NULL == (str_size = (size_t *)H5MM_malloc(2 * layout->storage.u.virt.list_nused * sizeof(size_t))))
+        if(NULL == (str_size = (size_t *)H5MM_malloc(2 * virt->list_nused * sizeof(size_t))))
             HGOTO_ERROR(H5E_OHDR, H5E_RESOURCE, FAIL, "unable to allocate string length array")
 
         /*
@@ -453,29 +456,30 @@ H5D__virtual_store_layout(H5F_t *f, H5O_layout_t *layout)
         block_size = (size_t)1 + H5F_SIZEOF_SIZE(f);
 
         /* Calculate size of each entry */
-        for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
+        for(i = 0; i < virt->list_nused; i++) {
+            H5O_storage_virtual_ent_t *ent = &virt->list[i];
             hssize_t select_serial_size;        /* Size of serialized selection */
 
-            HDassert(layout->storage.u.virt.list[i].source_file_name);
-            HDassert(layout->storage.u.virt.list[i].source_dset_name);
-            HDassert(layout->storage.u.virt.list[i].source_select);
-            HDassert(layout->storage.u.virt.list[i].source_dset.virtual_select);
+            HDassert(ent->source_file_name);
+            HDassert(ent->source_dset_name);
+            HDassert(ent->source_select);
+            HDassert(ent->source_dset.virtual_select);
 
             /* Source file name */
-            str_size[2 * i] = HDstrlen(layout->storage.u.virt.list[i].source_file_name) + (size_t)1;
+            str_size[2 * i] = HDstrlen(ent->source_file_name) + (size_t)1;
             block_size += str_size[2 * i];
 
             /* Source dset name */
-            str_size[(2 * i) + 1] = HDstrlen(layout->storage.u.virt.list[i].source_dset_name) + (size_t)1;
+            str_size[(2 * i) + 1] = HDstrlen(ent->source_dset_name) + (size_t)1;
             block_size += str_size[(2 * i) + 1];
 
             /* Source selection */
-            if((select_serial_size = H5S_SELECT_SERIAL_SIZE(layout->storage.u.virt.list[i].source_select)) < 0)
+            if((select_serial_size = H5S_SELECT_SERIAL_SIZE(ent->source_select)) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTENCODE, FAIL, "unable to check dataspace selection size")
             block_size += (size_t)select_serial_size;
 
             /* Virtual dataset selection */
-            if((select_serial_size = H5S_SELECT_SERIAL_SIZE(layout->storage.u.virt.list[i].source_dset.virtual_select)) < 0)
+            if((select_serial_size = H5S_SELECT_SERIAL_SIZE(ent->source_dset.virtual_select)) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTENCODE, FAIL, "unable to check dataspace selection size")
             block_size += (size_t)select_serial_size;
         } /* end for */
@@ -498,25 +502,26 @@ H5D__virtual_store_layout(H5F_t *f, H5O_layout_t *layout)
         *heap_block_p++ = (uint8_t)H5O_LAYOUT_VDS_GH_ENC_VERS;
 
         /* Number of entries */
-        tmp_nentries = (hsize_t)layout->storage.u.virt.list_nused;
+        tmp_nentries = (hsize_t)virt->list_nused;
         H5F_ENCODE_LENGTH(f, heap_block_p, tmp_nentries)
 
         /* Encode each entry */
-        for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
+        for(i = 0; i < virt->list_nused; i++) {
+            H5O_storage_virtual_ent_t *ent = &virt->list[i];
             /* Source file name */
-            H5MM_memcpy((char *)heap_block_p, layout->storage.u.virt.list[i].source_file_name, str_size[2 * i]);
+            H5MM_memcpy((char *)heap_block_p, ent->source_file_name, str_size[2 * i]);
             heap_block_p += str_size[2 * i];
 
             /* Source dataset name */
-            H5MM_memcpy((char *)heap_block_p, layout->storage.u.virt.list[i].source_dset_name, str_size[(2 * i) + 1]);
+            H5MM_memcpy((char *)heap_block_p, ent->source_dset_name, str_size[(2 * i) + 1]);
             heap_block_p += str_size[(2 * i) + 1];
 
             /* Source selection */
-            if(H5S_SELECT_SERIALIZE(layout->storage.u.virt.list[i].source_select, &heap_block_p) < 0)
+            if(H5S_SELECT_SERIALIZE(ent->source_select, &heap_block_p) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to serialize source selection")
 
             /* Virtual selection */
-            if(H5S_SELECT_SERIALIZE(layout->storage.u.virt.list[i].source_dset.virtual_select, &heap_block_p) < 0)
+            if(H5S_SELECT_SERIALIZE(ent->source_dset.virtual_select, &heap_block_p) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to serialize virtual selection")
         } /* end for */
 
@@ -525,7 +530,7 @@ H5D__virtual_store_layout(H5F_t *f, H5O_layout_t *layout)
         UINT32ENCODE(heap_block_p, chksum)
 
         /* Insert block into global heap */
-        if(H5HG_insert(f, block_size, heap_block, &(layout->storage.u.virt.serial_list_hobjid)) < 0) /* Casting away const OK  --NAF */
+        if(H5HG_insert(f, block_size, heap_block, &(virt->serial_list_hobjid)) < 0) /* Casting away const OK  --NAF */
             HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "unable to insert virtual dataset heap block")
     } /* end if */
 
@@ -556,6 +561,7 @@ herr_t
 H5D__virtual_copy_layout(H5O_layout_t *layout)
 {
     H5O_storage_virtual_ent_t *orig_list = NULL;
+    H5O_storage_virtual_t *virt = &layout->storage.u.virt;
     hid_t           orig_source_fapl;
     hid_t           orig_source_dapl;
     H5P_genplist_t *plist;
@@ -569,127 +575,129 @@ H5D__virtual_copy_layout(H5O_layout_t *layout)
 
     /* Save original entry list and top-level property lists and reset in layout
      * so the originals aren't closed on error */
-    orig_source_fapl = layout->storage.u.virt.source_fapl;
-    layout->storage.u.virt.source_fapl = -1;
-    orig_source_dapl = layout->storage.u.virt.source_dapl;
-    layout->storage.u.virt.source_dapl = -1;
-    orig_list = layout->storage.u.virt.list;
-    layout->storage.u.virt.list = NULL;
+    orig_source_fapl = virt->source_fapl;
+    virt->source_fapl = -1;
+    orig_source_dapl = virt->source_dapl;
+    virt->source_dapl = -1;
+    orig_list = virt->list;
+    virt->list = NULL;
 
     /* Copy entry list */
-    if(layout->storage.u.virt.list_nused > 0) {
+    if(virt->list_nused > 0) {
         HDassert(orig_list);
 
         /* Allocate memory for the list */
-        if(NULL == (layout->storage.u.virt.list = (H5O_storage_virtual_ent_t *)H5MM_calloc(layout->storage.u.virt.list_nused * sizeof(H5O_storage_virtual_ent_t))))
+        if(NULL == (virt->list = H5MM_calloc(virt->list_nused * sizeof(virt->list[0]))))
             HGOTO_ERROR(H5E_DATASET, H5E_CANTALLOC, FAIL, "unable to allocate memory for virtual dataset entry list")
-        layout->storage.u.virt.list_nalloc = layout->storage.u.virt.list_nused;
+        virt->list_nalloc = virt->list_nused;
 
         /* Copy the list entries, though set source_dset.dset and sub_dset to
          * NULL */
-        for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
+        for(i = 0; i < virt->list_nused; i++) {
+            H5O_storage_virtual_ent_t *ent = &virt->list[i];
+
             /* Copy virtual selection */
-            if(NULL == (layout->storage.u.virt.list[i].source_dset.virtual_select
+            if(NULL == (ent->source_dset.virtual_select
                     = H5S_copy(orig_list[i].source_dset.virtual_select, FALSE, TRUE)))
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")
 
             /* Copy original source names */
-            if(NULL == (layout->storage.u.virt.list[i].source_file_name
+            if(NULL == (ent->source_file_name
                     = H5MM_strdup(orig_list[i].source_file_name)))
                 HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source file name")
-            if(NULL == (layout->storage.u.virt.list[i].source_dset_name
+            if(NULL == (ent->source_dset_name
                     = H5MM_strdup(orig_list[i].source_dset_name)))
                 HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source dataset name")
 
             /* Copy source selection */
-            if(NULL == (layout->storage.u.virt.list[i].source_select
+            if(NULL == (ent->source_select
                     = H5S_copy(orig_list[i].source_select, FALSE, TRUE)))
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy source selection")
 
             /* Initialize clipped selections */
             if(orig_list[i].unlim_dim_virtual < 0) {
-                layout->storage.u.virt.list[i].source_dset.clipped_source_select = layout->storage.u.virt.list[i].source_select;
-                layout->storage.u.virt.list[i].source_dset.clipped_virtual_select = layout->storage.u.virt.list[i].source_dset.virtual_select;
+                ent->source_dset.clipped_source_select = ent->source_select;
+                ent->source_dset.clipped_virtual_select = ent->source_dset.virtual_select;
             } /* end if */
 
             /* Copy parsed names */
-            if(H5D__virtual_copy_parsed_name(&layout->storage.u.virt.list[i].parsed_source_file_name, orig_list[i].parsed_source_file_name) < 0)
+            if(H5D__virtual_copy_parsed_name(&ent->parsed_source_file_name, orig_list[i].parsed_source_file_name) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy parsed source file name")
-            layout->storage.u.virt.list[i].psfn_static_strlen = orig_list[i].psfn_static_strlen;
-            layout->storage.u.virt.list[i].psfn_nsubs = orig_list[i].psfn_nsubs;
-            if(H5D__virtual_copy_parsed_name(&layout->storage.u.virt.list[i].parsed_source_dset_name, orig_list[i].parsed_source_dset_name) < 0)
+            ent->psfn_static_strlen = orig_list[i].psfn_static_strlen;
+            ent->psfn_nsubs = orig_list[i].psfn_nsubs;
+            if(H5D__virtual_copy_parsed_name(&ent->parsed_source_dset_name, orig_list[i].parsed_source_dset_name) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy parsed source dataset name")
-            layout->storage.u.virt.list[i].psdn_static_strlen = orig_list[i].psdn_static_strlen;
-            layout->storage.u.virt.list[i].psdn_nsubs = orig_list[i].psdn_nsubs;
+            ent->psdn_static_strlen = orig_list[i].psdn_static_strlen;
+            ent->psdn_nsubs = orig_list[i].psdn_nsubs;
 
             /* Copy source names in source dset or add reference as appropriate
              */
             if(orig_list[i].source_dset.file_name) {
                 if(orig_list[i].source_dset.file_name
                         == orig_list[i].source_file_name)
-                    layout->storage.u.virt.list[i].source_dset.file_name = layout->storage.u.virt.list[i].source_file_name;
+                    ent->source_dset.file_name = ent->source_file_name;
                 else if(orig_list[i].parsed_source_file_name
                         && (orig_list[i].source_dset.file_name
                         != orig_list[i].parsed_source_file_name->name_segment)) {
-                    HDassert(layout->storage.u.virt.list[i].parsed_source_file_name);
-                    HDassert(layout->storage.u.virt.list[i].parsed_source_file_name->name_segment);
-                    layout->storage.u.virt.list[i].source_dset.file_name = layout->storage.u.virt.list[i].parsed_source_file_name->name_segment;
+                    HDassert(ent->parsed_source_file_name);
+                    HDassert(ent->parsed_source_file_name->name_segment);
+                    ent->source_dset.file_name = ent->parsed_source_file_name->name_segment;
                 } /* end if */
                 else
-                    if(NULL == (layout->storage.u.virt.list[i].source_dset.file_name
+                    if(NULL == (ent->source_dset.file_name
                             = H5MM_strdup(orig_list[i].source_dset.file_name)))
                         HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source file name")
             } /* end if */
             if(orig_list[i].source_dset.dset_name) {
                 if(orig_list[i].source_dset.dset_name
                         == orig_list[i].source_dset_name)
-                    layout->storage.u.virt.list[i].source_dset.dset_name = layout->storage.u.virt.list[i].source_dset_name;
+                    ent->source_dset.dset_name = ent->source_dset_name;
                 else if(orig_list[i].parsed_source_dset_name
                         && (orig_list[i].source_dset.dset_name
                         != orig_list[i].parsed_source_dset_name->name_segment)) {
-                    HDassert(layout->storage.u.virt.list[i].parsed_source_dset_name);
-                    HDassert(layout->storage.u.virt.list[i].parsed_source_dset_name->name_segment);
-                    layout->storage.u.virt.list[i].source_dset.dset_name = layout->storage.u.virt.list[i].parsed_source_dset_name->name_segment;
+                    HDassert(ent->parsed_source_dset_name);
+                    HDassert(ent->parsed_source_dset_name->name_segment);
+                    ent->source_dset.dset_name = ent->parsed_source_dset_name->name_segment;
                 } /* end if */
                 else
-                    if(NULL == (layout->storage.u.virt.list[i].source_dset.dset_name
+                    if(NULL == (ent->source_dset.dset_name
                             = H5MM_strdup(orig_list[i].source_dset.dset_name)))
                         HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source dataset name")
             } /* end if */
 
             /* Copy other fields in entry */
-            layout->storage.u.virt.list[i].unlim_dim_source = orig_list[i].unlim_dim_source;
-            layout->storage.u.virt.list[i].unlim_dim_virtual = orig_list[i].unlim_dim_virtual;
-            layout->storage.u.virt.list[i].unlim_extent_source = orig_list[i].unlim_extent_source;
-            layout->storage.u.virt.list[i].unlim_extent_virtual = orig_list[i].unlim_extent_virtual;
-            layout->storage.u.virt.list[i].clip_size_source = orig_list[i].clip_size_source;
-            layout->storage.u.virt.list[i].clip_size_virtual = orig_list[i].clip_size_virtual;
-            layout->storage.u.virt.list[i].source_space_status = orig_list[i].source_space_status;
-            layout->storage.u.virt.list[i].virtual_space_status = orig_list[i].virtual_space_status;
+            ent->unlim_dim_source = orig_list[i].unlim_dim_source;
+            ent->unlim_dim_virtual = orig_list[i].unlim_dim_virtual;
+            ent->unlim_extent_source = orig_list[i].unlim_extent_source;
+            ent->unlim_extent_virtual = orig_list[i].unlim_extent_virtual;
+            ent->clip_size_source = orig_list[i].clip_size_source;
+            ent->clip_size_virtual = orig_list[i].clip_size_virtual;
+            ent->source_space_status = orig_list[i].source_space_status;
+            ent->virtual_space_status = orig_list[i].virtual_space_status;
         } /* end for */
     } /* end if */
     else {
         /* Zero out other fields related to list, just to be sure */
-        layout->storage.u.virt.list = NULL;
-        layout->storage.u.virt.list_nalloc = 0;
+        virt->list = NULL;
+        virt->list_nalloc = 0;
     } /* end else */
 
     /* Copy property lists */
     if(orig_source_fapl >= 0) {
         if(NULL == (plist = (H5P_genplist_t *)H5I_object_verify(orig_source_fapl, H5I_GENPROP_LST)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
-        if((layout->storage.u.virt.source_fapl = H5P_copy_plist(plist, FALSE)) < 0)
+        if((virt->source_fapl = H5P_copy_plist(plist, FALSE)) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy fapl")
     } /* end if */
     if(orig_source_dapl >= 0) {
         if(NULL == (plist = (H5P_genplist_t *)H5I_object_verify(orig_source_dapl, H5I_GENPROP_LST)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
-        if((layout->storage.u.virt.source_dapl = H5P_copy_plist(plist, FALSE)) < 0)
+        if((virt->source_dapl = H5P_copy_plist(plist, FALSE)) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy dapl")
     } /* end if */
 
     /* New layout is not fully initialized */
-    layout->storage.u.virt.init = FALSE;
+    virt->init = FALSE;
 
 done:
     /* Release allocated resources on failure */
@@ -721,6 +729,7 @@ herr_t
 H5D__virtual_reset_layout(H5O_layout_t *layout)
 {
     size_t          i, j;
+    H5O_storage_virtual_t *virt = &layout->storage.u.virt;
     herr_t          ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
@@ -731,53 +740,54 @@ H5D__virtual_reset_layout(H5O_layout_t *layout)
     /* Free the list entries.  Note we always attempt to free everything even in
      * the case of a failure.  Because of this, and because we free the list
      * afterwards, we do not need to zero out the memory in the list. */
-    for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
+    for(i = 0; i < virt->list_nused; i++) {
+        H5O_storage_virtual_ent_t *ent = &virt->list[i];
         /* Free source_dset */
-        if(H5D__virtual_reset_source_dset(&layout->storage.u.virt.list[i], &layout->storage.u.virt.list[i].source_dset) < 0)
+        if(H5D__virtual_reset_source_dset(ent, &ent->source_dset) < 0)
             HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "unable to reset source dataset")
 
         /* Free original source names */
-        (void)H5MM_xfree(layout->storage.u.virt.list[i].source_file_name);
-        (void)H5MM_xfree(layout->storage.u.virt.list[i].source_dset_name);
+        (void)H5MM_xfree(ent->source_file_name);
+        (void)H5MM_xfree(ent->source_dset_name);
 
         /* Free sub_dset */
-        for(j = 0; j < layout->storage.u.virt.list[i].sub_dset_nalloc; j++)
-            if(H5D__virtual_reset_source_dset(&layout->storage.u.virt.list[i], &layout->storage.u.virt.list[i].sub_dset[j]) < 0)
+        for(j = 0; j < ent->sub_dset_nalloc; j++)
+            if(H5D__virtual_reset_source_dset(ent, &ent->sub_dset[j]) < 0)
                 HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "unable to reset source dataset")
-        layout->storage.u.virt.list[i].sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_xfree(layout->storage.u.virt.list[i].sub_dset);
+        ent->sub_dset = H5MM_xfree(ent->sub_dset);
 
         /* Free source_select */
-        if(layout->storage.u.virt.list[i].source_select)
-            if(H5S_close(layout->storage.u.virt.list[i].source_select) < 0)
+        if(ent->source_select)
+            if(H5S_close(ent->source_select) < 0)
                 HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release source selection")
 
         /* Free parsed_source_file_name */
-        H5D_virtual_free_parsed_name(layout->storage.u.virt.list[i].parsed_source_file_name);
+        H5D_virtual_free_parsed_name(ent->parsed_source_file_name);
 
         /* Free parsed_source_dset_name */
-        H5D_virtual_free_parsed_name(layout->storage.u.virt.list[i].parsed_source_dset_name);
-    } /* end for */
+        H5D_virtual_free_parsed_name(ent->parsed_source_dset_name);
+    }
 
     /* Free the list */
-    layout->storage.u.virt.list = (H5O_storage_virtual_ent_t *)H5MM_xfree(layout->storage.u.virt.list);
-    layout->storage.u.virt.list_nalloc = (size_t)0;
-    layout->storage.u.virt.list_nused = (size_t)0;
-    (void)HDmemset(layout->storage.u.virt.min_dims, 0, sizeof(layout->storage.u.virt.min_dims));
+    virt->list = H5MM_xfree(virt->list);
+    virt->list_nalloc = (size_t)0;
+    virt->list_nused = (size_t)0;
+    (void)HDmemset(virt->min_dims, 0, sizeof(virt->min_dims));
 
     /* Close access property lists */
-    if(layout->storage.u.virt.source_fapl >= 0) {
-        if(H5I_dec_ref(layout->storage.u.virt.source_fapl) < 0)
+    if(virt->source_fapl >= 0) {
+        if(H5I_dec_ref(virt->source_fapl) < 0)
             HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "can't close source fapl")
-        layout->storage.u.virt.source_fapl = -1;
-    } /* end if */
-    if(layout->storage.u.virt.source_dapl >= 0) {
-        if(H5I_dec_ref(layout->storage.u.virt.source_dapl) < 0)
+        virt->source_fapl = -1;
+    }
+    if(virt->source_dapl >= 0) {
+        if(H5I_dec_ref(virt->source_dapl) < 0)
             HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "can't close source dapl")
-        layout->storage.u.virt.source_dapl = -1;
-    } /* end if */
+        virt->source_dapl = -1;
+    }
 
     /* The list is no longer initialized */
-    layout->storage.u.virt.init = FALSE;
+    virt->init = FALSE;
 
     /* Note the lack of a done: label.  This is because there are no HGOTO_ERROR
      * calls.  If one is added, a done: label must also be added */
@@ -2781,7 +2791,7 @@ H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
          * extent in the unlimited dimension.  -NAF */
         /* Project intersection of file space and mapping virtual space onto
          * mapping source space */
-        if(H5S_select_project_intersection(source_dset->virtual_select, source_dset->clipped_source_select, file_space, &projected_src_space, TRUE) < 0)
+        if(H5S_select_project_intersection(source_dset->clipped_virtual_select, source_dset->clipped_source_select, file_space, &projected_src_space, TRUE) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")
 
         /* Perform write on source dataset */
diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index 7608d61..14c896a 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -381,7 +381,9 @@ H5FD__core_write_to_bstore(H5FD_core_t *file, haddr_t addr, size_t size)
             int myerrno = errno;
             time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
             offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write to backing store failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', ptr = %p, total write size = %llu, bytes this sub-write = %llu, bytes actually written = %llu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), ptr, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_wrote, (unsigned long long)offset);
         } /* end if */
@@ -803,7 +805,9 @@ H5FD__core_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr
                         int myerrno = errno;
                         time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
                         offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
                         HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', file->mem = %p, total read size = %llu, bytes this sub-read = %llu, bytes actually read = %llu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), file->mem, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_read, (unsigned long long)offset);
                     } /* end if */
diff --git a/src/H5FDlog.c b/src/H5FDlog.c
index 5d1b536..cbd475f 100644
--- a/src/H5FDlog.c
+++ b/src/H5FDlog.c
@@ -81,8 +81,10 @@ typedef struct H5FD_log_t {
     int             fd;     /* the unix file                    */
     haddr_t         eoa;    /* end of allocated region          */
     haddr_t         eof;    /* end of file; current file size   */
+#ifndef H5_HAVE_PREADWRITE
     haddr_t         pos;    /* current file I/O position        */
     H5FD_file_op_t  op;     /* last operation                   */
+#endif /* H5_HAVE_PREADWRITE */
     hbool_t         ignore_disabled_file_locks;
     char            filename[H5FD_MAX_FILENAME_LEN];    /* Copy of file name from open operation */
 #ifndef H5_HAVE_WIN32_API
@@ -571,8 +573,10 @@ H5FD__log_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
 
     file->fd = fd;
     H5_CHECKED_ASSIGN(file->eof, haddr_t, sb.st_size, h5_stat_size_t);
+#ifndef H5_HAVE_PREADWRITE
     file->pos = HADDR_UNDEF;
     file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
 #ifdef H5_HAVE_WIN32_API
     file->hFile = (HANDLE)_get_osfhandle(fd);
     if(INVALID_HANDLE_VALUE == file->hFile)
@@ -1280,7 +1284,9 @@ H5FD__log_read(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, had
             int myerrno = errno;
             time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
             offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
             if(file->fa.flags & H5FD_LOG_LOC_READ)
                 HDfprintf(file->logfp, "Error! Reading: %10a-%10a (%10Zu bytes)\n", orig_addr, (orig_addr + orig_size) - 1, orig_size);
@@ -1337,15 +1343,19 @@ H5FD__log_read(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, had
             HDfprintf(file->logfp, "\n");
     } /* end if */
 
+#ifndef H5_HAVE_PREADWRITE
     /* Update current position */
     file->pos = addr;
     file->op = OP_READ;
+#endif /* H5_HAVE_PREADWRITE */
 
 done:
     if(ret_value < 0) {
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1489,7 +1499,9 @@ H5FD__log_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, ha
             int myerrno = errno;
             time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
             offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
             if(file->fa.flags & H5FD_LOG_LOC_WRITE)
                 HDfprintf(file->logfp, "Error! Writing: %10a-%10a (%10Zu bytes)\n", orig_addr, (orig_addr + orig_size) - 1, orig_size);
@@ -1541,17 +1553,24 @@ H5FD__log_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, ha
              HDfprintf(file->logfp, "\n");
     } /* end if */
 
+#ifndef H5_HAVE_PREADWRITE
     /* Update current position and eof */
     file->pos = addr;
     file->op = OP_WRITE;
     if(file->pos > file->eof)
         file->eof = file->pos;
+#else /* H5_HAVE_PREADWRITE */
+    if(addr > file->eof)
+        file->eof = addr;
+#endif /* H5_HAVE_PREADWRITE */
 
 done:
     if(ret_value < 0) {
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1656,9 +1675,11 @@ H5FD__log_truncate(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t H5_ATTR_
         /* Update the eof value */
         file->eof = file->eoa;
 
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
 done:
diff --git a/src/H5FDprivate.h b/src/H5FDprivate.h
index c5bc043..c7994ac 100644
--- a/src/H5FDprivate.h
+++ b/src/H5FDprivate.h
@@ -59,12 +59,14 @@ typedef struct H5FD_class_mpi_t {
 /* Library Private Typedefs */
 /****************************/
 
+#ifndef H5_HAVE_PREADWRITE
 /* File operations */
 typedef enum {
     OP_UNKNOWN = 0,             /* Unknown last file operation */
     OP_READ = 1,                /* Last file I/O operation was a read */
     OP_WRITE = 2                /* Last file I/O operation was a write */
 } H5FD_file_op_t;
+#endif /* H5_HAVE_PREADWRITE */
 
 
 /* Define structure to hold initial file image and other relevant information */
diff --git a/src/H5FDsec2.c b/src/H5FDsec2.c
index 147d08f..6a16838 100644
--- a/src/H5FDsec2.c
+++ b/src/H5FDsec2.c
@@ -58,8 +58,10 @@ typedef struct H5FD_sec2_t {
     int             fd;     /* the filesystem file descriptor   */
     haddr_t         eoa;    /* end of allocated region          */
     haddr_t         eof;    /* end of file; current file size   */
+#ifndef H5_HAVE_PREADWRITE
     haddr_t         pos;    /* current file I/O position        */
     H5FD_file_op_t  op;     /* last operation                   */
+#endif /* H5_HAVE_PREADWRITE */
     hbool_t         ignore_disabled_file_locks;
     char            filename[H5FD_MAX_FILENAME_LEN];    /* Copy of file name from open operation */
 #ifndef H5_HAVE_WIN32_API
@@ -369,8 +371,10 @@ H5FD__sec2_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr
 
     file->fd = fd;
     H5_CHECKED_ASSIGN(file->eof, haddr_t, sb.st_size, h5_stat_size_t);
+#ifndef H5_HAVE_PREADWRITE
     file->pos = HADDR_UNDEF;
     file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
 #ifdef H5_HAVE_WIN32_API
     file->hFile = (HANDLE)_get_osfhandle(fd);
     if(INVALID_HANDLE_VALUE == file->hFile)
@@ -748,7 +752,9 @@ H5FD__sec2_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
             int myerrno = errno;
             time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
             offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
             HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', buf = %p, total read size = %llu, bytes this sub-read = %llu, bytes actually read = %llu, offset = %llu", HDctime(&mytime), file->filename, file->fd, myerrno, HDstrerror(myerrno), buf, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_read, (unsigned long long)offset);
         } /* end if */
@@ -767,15 +773,19 @@ H5FD__sec2_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
         buf = (char *)buf + bytes_read;
     } /* end while */
 
+#ifndef H5_HAVE_PREADWRITE
     /* Update current position */
     file->pos = addr;
     file->op = OP_READ;
+#endif /* H5_HAVE_PREADWRITE */
 
 done:
     if(ret_value < 0) {
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -851,7 +861,9 @@ H5FD__sec2_write(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UN
             int myerrno = errno;
             time_t mytime = HDtime(NULL);
 
+#ifndef H5_HAVE_PREADWRITE
             offset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+#endif /* H5_HAVE_PREADWRITE */
 
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', buf = %p, total write size = %llu, bytes this sub-write = %llu, bytes actually written = %llu, offset = %llu", HDctime(&mytime), file->filename, file->fd, myerrno, HDstrerror(myerrno), buf, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_wrote, (unsigned long long)offset);
         } /* end if */
@@ -864,17 +876,24 @@ H5FD__sec2_write(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UN
         buf = (const char *)buf + bytes_wrote;
     } /* end while */
 
+#ifndef H5_HAVE_PREADWRITE
     /* Update current position and eof */
     file->pos = addr;
     file->op = OP_WRITE;
     if(file->pos > file->eof)
         file->eof = file->pos;
+#else /* H5_HAVE_PREADWRITE */
+    if(addr > file->eof)
+        file->eof = addr;
+#endif /* H5_HAVE_PREADWRITE */
 
 done:
     if(ret_value < 0) {
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -940,9 +959,11 @@ H5FD__sec2_truncate(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t H5_ATTR
         /* Update the eof value */
         file->eof = file->eoa;
 
+#ifndef H5_HAVE_PREADWRITE
         /* Reset last file I/O information */
         file->pos = HADDR_UNDEF;
         file->op = OP_UNKNOWN;
+#endif /* H5_HAVE_PREADWRITE */
     } /* end if */
 
 done:
diff --git a/src/H5private.h b/src/H5private.h
index 7793e0b..c16c461 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -1512,6 +1512,9 @@ typedef off_t               h5_stat_size_t;
 #ifndef HDstrtoull
     #define HDstrtoull(S,R,N)  strtoull(S,R,N)
 #endif /* HDstrtoul */
+#ifndef HDstrtoumax
+    #define HDstrtoumax(S,R,N)  strtoumax(S,R,N)
+#endif /* HDstrtoumax */
 #ifndef HDstrxfrm
     #define HDstrxfrm(X,Y,Z)  strxfrm(X,Y,Z)
 #endif /* HDstrxfrm */