[svn-r15015] Description:

    Detect chunks that are >4GB before dataset gets created and return error
to application.

    Tweak lots of internal variables that hold the chunk size/dimensions to
use an 'uint32_t', instead of a 'size_t', so that the integer size is constant.

    Correct a number of our tests which were creating datasets with chunks
that were >4GB and add some specific tests for >4GB chunk size detection.

    Minor whitespace & other code cleanups.

Tested on:
    Mac OS X/32 10.5.2 (amazon)
    Forthcoming testing on other platforms...

13 files changed, 399 insertions, 235 deletions

diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index baaa5f1..ba07725 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -189,16 +189,16 @@ H5D_chunk_io_init(const H5D_io_info_t *io_info, const H5D_type_info_t *type_info
         HGOTO_ERROR(H5E_DATASET, H5E_BADSELECT, FAIL, "unable to normalize dataspace by offset")
 
     /* Decide the number of chunks in each dimension*/
-    for(u=0; u<f_ndims; u++) {
+    for(u = 0; u < f_ndims; u++) {
         /* Keep the size of the chunk dimensions as hsize_t for various routines */
-        fm->chunk_dim[u]=fm->layout->u.chunk.dim[u];
+        fm->chunk_dim[u] = fm->layout->u.chunk.dim[u];
 
         /* Round up to the next integer # of chunks, to accomodate partial chunks */
-        fm->chunks[u] = ((fm->f_dims[u]+dataset->shared->layout.u.chunk.dim[u])-1) / dataset->shared->layout.u.chunk.dim[u];
+        fm->chunks[u] = ((fm->f_dims[u] + dataset->shared->layout.u.chunk.dim[u]) - 1) / dataset->shared->layout.u.chunk.dim[u];
     } /* end for */
 
     /* Compute the "down" size of 'chunks' information */
-    if(H5V_array_down(f_ndims,fm->chunks,fm->down_chunks) < 0)
+    if(H5V_array_down(f_ndims, fm->chunks, fm->down_chunks) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "can't compute 'down' sizes")
 
 #ifdef H5_HAVE_PARALLEL
@@ -591,16 +591,15 @@ H5D_create_chunk_file_map_hyper(H5D_chunk_map_t *fm, const H5D_io_info_t
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get file selection bound info")
 
     /* Set initial chunk location & hyperslab size */
-
-    for(u=0; u<fm->f_ndims; u++) {
-        start_coords[u]=(sel_start[u]/fm->layout->u.chunk.dim[u])*fm->layout->u.chunk.dim[u];
-        coords[u]=start_coords[u];
-        end[u]=(coords[u]+fm->chunk_dim[u])-1;
+    for(u = 0; u < fm->f_ndims; u++) {
+        start_coords[u] = (sel_start[u] / fm->layout->u.chunk.dim[u]) * fm->layout->u.chunk.dim[u];
+        coords[u] = start_coords[u];
+        end[u] = (coords[u] + fm->chunk_dim[u]) - 1;
     } /* end for */
 
 
     /* Calculate the index of this chunk */
-    if(H5V_chunk_index(fm->f_ndims,coords,fm->layout->u.chunk.dim,fm->down_chunks,&chunk_index) < 0)
+    if(H5V_chunk_index(fm->f_ndims, coords, fm->layout->u.chunk.dim, fm->down_chunks, &chunk_index) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
 
     /* Iterate through each chunk in the dataset */
@@ -679,17 +678,16 @@ H5D_create_chunk_file_map_hyper(H5D_chunk_map_t *fm, const H5D_io_info_t
             } /* end if */
 
             /* Get number of elements selected in chunk */
-            if((schunk_points=H5S_GET_SELECT_NPOINTS(tmp_fchunk)) < 0)
+            if((schunk_points = H5S_GET_SELECT_NPOINTS(tmp_fchunk)) < 0)
                 HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't get file selection # of elements")
-            H5_ASSIGN_OVERFLOW(new_chunk_info->chunk_points,schunk_points,hssize_t,size_t);
+            H5_ASSIGN_OVERFLOW(new_chunk_info->chunk_points, schunk_points, hssize_t, uint32_t);
 
             /* Decrement # of points left in file selection */
-            sel_points-=(hsize_t)schunk_points;
+            sel_points -= (hsize_t)schunk_points;
 
             /* Leave if we are done */
-            if(sel_points==0)
+            if(sel_points == 0)
                 HGOTO_DONE(SUCCEED)
-            assert(sel_points>0);
         } /* end if */
 
         /* Increment chunk index */
@@ -719,7 +717,7 @@ H5D_create_chunk_file_map_hyper(H5D_chunk_map_t *fm, const H5D_io_info_t
             } while(coords[curr_dim]>sel_end[curr_dim]);
 
             /* Re-Calculate the index of this chunk */
-            if(H5V_chunk_index(fm->f_ndims,coords,fm->layout->u.chunk.dim,fm->down_chunks,&chunk_index) < 0)
+            if(H5V_chunk_index(fm->f_ndims, coords, fm->layout->u.chunk.dim, fm->down_chunks, &chunk_index) < 0)
                 HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
         } /* end if */
     } /* end while */
@@ -867,7 +865,7 @@ H5D_chunk_file_cb(void UNUSED *elem, hid_t UNUSED type_id, unsigned ndims, const
     FUNC_ENTER_NOAPI_NOINIT(H5D_chunk_file_cb)
 
     /* Calculate the index of this chunk */
-    if(H5V_chunk_index(ndims,coords,fm->layout->u.chunk.dim,fm->down_chunks,&chunk_index) < 0)
+    if(H5V_chunk_index(ndims, coords, fm->layout->u.chunk.dim, fm->down_chunks, &chunk_index) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
 
     /* Find correct chunk in file & memory skip list */
@@ -912,18 +910,18 @@ H5D_chunk_file_cb(void UNUSED *elem, hid_t UNUSED type_id, unsigned ndims, const
             chunk_info->fspace_shared = FALSE;
 
             /* Set the memory chunk dataspace */
-            chunk_info->mspace=NULL;
+            chunk_info->mspace = NULL;
             chunk_info->mspace_shared = FALSE;
 
             /* Set the number of selected elements in chunk to zero */
-            chunk_info->chunk_points=0;
+            chunk_info->chunk_points = 0;
 
             /* Compute the chunk's coordinates */
-            for(u=0; u<fm->f_ndims; u++) {
-                H5_CHECK_OVERFLOW(fm->layout->u.chunk.dim[u],hsize_t,hssize_t);
-                chunk_info->coords[u]=(coords[u]/(hssize_t)fm->layout->u.chunk.dim[u])*(hssize_t)fm->layout->u.chunk.dim[u];
+            for(u = 0; u < fm->f_ndims; u++) {
+                H5_CHECK_OVERFLOW(fm->layout->u.chunk.dim[u], hsize_t, hssize_t);
+                chunk_info->coords[u] = (coords[u] / (hssize_t)fm->layout->u.chunk.dim[u]) * (hssize_t)fm->layout->u.chunk.dim[u];
             } /* end for */
-            chunk_info->coords[fm->f_ndims]=0;
+            chunk_info->coords[fm->f_ndims] = 0;
 
             /* Insert the new chunk into the skip list */
             if(H5SL_insert(fm->sel_chunks,chunk_info,&chunk_info->index) < 0) {
@@ -938,8 +936,8 @@ H5D_chunk_file_cb(void UNUSED *elem, hid_t UNUSED type_id, unsigned ndims, const
     } /* end else */
 
     /* Get the coordinates of the element in the chunk */
-    for(u=0; u<fm->f_ndims; u++)
-        coords_in_chunk[u]=coords[u]%fm->layout->u.chunk.dim[u];
+    for(u = 0; u < fm->f_ndims; u++)
+        coords_in_chunk[u] = coords[u] % fm->layout->u.chunk.dim[u];
 
     /* Add point to file selection for chunk */
     if(H5S_select_elements(chunk_info->fspace, H5S_SELECT_APPEND, (size_t)1, coords_in_chunk) < 0)
@@ -979,7 +977,7 @@ H5D_chunk_mem_cb(void UNUSED *elem, hid_t UNUSED type_id, unsigned ndims, const
     FUNC_ENTER_NOAPI_NOINIT(H5D_chunk_mem_cb)
 
     /* Calculate the index of this chunk */
-    if(H5V_chunk_index(ndims,coords,fm->layout->u.chunk.dim,fm->down_chunks,&chunk_index) < 0)
+    if(H5V_chunk_index(ndims, coords, fm->layout->u.chunk.dim, fm->down_chunks, &chunk_index) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
 
     /* Find correct chunk in file & memory skip list */
@@ -1059,7 +1057,7 @@ H5D_chunk_cacheable(const H5D_io_info_t *io_info, haddr_t caddr)
     /* Must bring the whole chunk in if there are any filters */
     if(dataset->shared->dcpl_cache.pline.nused > 0)
         ret_value = TRUE;
-    else
+    else {
 #ifdef H5_HAVE_PARALLEL
          /* If MPI based VFD is used and the file is opened for write access, must
           *         bypass the chunk-cache scheme because other MPI processes could
@@ -1068,17 +1066,22 @@ H5D_chunk_cacheable(const H5D_io_info_t *io_info, haddr_t caddr)
           */
         if(io_info->using_mpi_vfd && (H5F_ACC_RDWR & H5F_INTENT(dataset->oloc.file)))
             ret_value = FALSE;
-        else
+        else {
 #endif /* H5_HAVE_PARALLEL */
             /* If the chunk is too large to keep in the cache and if the address
              * for the chunk has been defined, then don't load the chunk into the
              * cache, just write the data to it directly.
              */
-            if(dataset->shared->layout.u.chunk.size > dataset->shared->cache.chunk.nbytes
+            H5_CHECK_OVERFLOW(dataset->shared->layout.u.chunk.size, uint32_t, size_t);
+            if((size_t)dataset->shared->layout.u.chunk.size > dataset->shared->cache.chunk.nbytes
                     && H5F_addr_defined(caddr))
                 ret_value = FALSE;
             else
                 ret_value = TRUE;
+#ifdef H5_HAVE_PARALLEL
+        } /* end else */
+#endif /* H5_HAVE_PARALLEL */
+    } /* end else */
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_chunk_cacheable() */
@@ -1152,7 +1155,7 @@ H5D_chunk_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     H5D_io_info_t cpt_io_info;          /* Compact I/O info object */
     H5D_storage_t cpt_store;            /* Chunk storage information as compact dataset */
     hbool_t     cpt_dirty;              /* Temporary placeholder for compact storage "dirty" flag */
-    size_t      src_accessed_bytes = 0; /* Total accessed size in a chunk */
+    uint32_t    src_accessed_bytes = 0; /* Total accessed size in a chunk */
     hbool_t     skip_missing_chunks = FALSE;    /* Whether to skip missing chunks */
     unsigned    idx_hint = 0;           /* Cache index hint      */
     herr_t	ret_value = SUCCEED;	/*return value		*/
@@ -1175,7 +1178,7 @@ H5D_chunk_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     ctg_io_info.layout_ops = *H5D_LOPS_CONTIG;
 
     /* Initialize temporary contiguous storage info */
-    ctg_store.contig.dset_size = (hsize_t)io_info->dset->shared->layout.u.chunk.size;
+    H5_ASSIGN_OVERFLOW(ctg_store.contig.dset_size, io_info->dset->shared->layout.u.chunk.size, uint32_t, hsize_t);
 
     /* Set up compact I/O info object */
     HDmemcpy(&cpt_io_info, io_info, sizeof(cpt_io_info));
@@ -1232,8 +1235,11 @@ H5D_chunk_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
         else {
             /* Load the chunk into cache and lock it. */
             if(H5D_chunk_cacheable(io_info, chunk_addr)) {
+                size_t tmp_src_accessed_bytes;      /* Total accessed size in a chunk */
+
                 /* Compute # of bytes accessed in chunk */
-                src_accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                tmp_src_accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                H5_ASSIGN_OVERFLOW(src_accessed_bytes, tmp_src_accessed_bytes, size_t, uint32_t);
 
                 /* Lock the chunk into the cache */
                 if(NULL == (chunk = H5D_istore_lock(io_info, &udata, FALSE, &idx_hint)))
@@ -1301,7 +1307,7 @@ H5D_chunk_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     H5D_io_info_t cpt_io_info;          /* Compact I/O info object */
     H5D_storage_t cpt_store;            /* Chunk storage information as compact dataset */
     hbool_t     cpt_dirty;              /* Temporary placeholder for compact storage "dirty" flag */
-    size_t      dst_accessed_bytes = 0; /* Total accessed size in a chunk */
+    uint32_t    dst_accessed_bytes = 0; /* Total accessed size in a chunk */
     unsigned    idx_hint = 0;           /* Cache index hint      */
     herr_t	ret_value = SUCCEED;	/* Return value		*/
 
@@ -1319,7 +1325,7 @@ H5D_chunk_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     ctg_io_info.layout_ops = *H5D_LOPS_CONTIG;
 
     /* Initialize temporary contiguous storage info */
-    ctg_store.contig.dset_size = (hsize_t)io_info->dset->shared->layout.u.chunk.size;
+    H5_ASSIGN_OVERFLOW(ctg_store.contig.dset_size, io_info->dset->shared->layout.u.chunk.size, uint32_t, hsize_t);
 
     /* Set up compact I/O info object */
     HDmemcpy(&cpt_io_info, io_info, sizeof(cpt_io_info));
@@ -1350,9 +1356,11 @@ H5D_chunk_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
         chunk_addr = H5D_istore_get_addr(io_info, &udata);
         if(H5D_chunk_cacheable(io_info, chunk_addr)) {
             hbool_t entire_chunk = TRUE;       /* Whether whole chunk is selected */
+            size_t tmp_dst_accessed_bytes;      /* Total accessed size in a chunk */
 
             /* Compute # of bytes accessed in chunk */
-            dst_accessed_bytes = chunk_info->chunk_points * type_info->dst_type_size;
+            tmp_dst_accessed_bytes = chunk_info->chunk_points * type_info->dst_type_size;
+            H5_ASSIGN_OVERFLOW(dst_accessed_bytes, tmp_dst_accessed_bytes, size_t, uint32_t);
 
             /* Determine if we will access all the data in the chunk */
             if(dst_accessed_bytes != ctg_store.contig.dset_size ||
diff --git a/src/H5Dint.c b/src/H5Dint.c
index acb95d2..f8577cc 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -1174,6 +1174,7 @@ H5D_create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
         case H5D_CHUNKED:
             {
                 hsize_t	max_dim[H5O_LAYOUT_NDIMS];      /* Maximum size of data in elements */
+                uint64_t chunk_size;                    /* Size of chunk in bytes */
 
                 /* Set up layout information */
                 if((ndims = H5S_GET_EXTENT_NDIMS(new_dset->shared->space)) < 0)
@@ -1208,8 +1209,17 @@ H5D_create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
                         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "chunk size must be <= maximum dimension size for fixed-sized dimensions")
 
                 /* Compute the total size of a chunk */
-                for(u = 1, new_dset->shared->layout.u.chunk.size = new_dset->shared->layout.u.chunk.dim[0]; u < new_dset->shared->layout.u.chunk.ndims; u++)
-                    new_dset->shared->layout.u.chunk.size *= new_dset->shared->layout.u.chunk.dim[u];
+                /* (Use 64-bit value to ensure that we can detect >4GB chunks) */
+                for(u = 1, chunk_size = (uint64_t)new_dset->shared->layout.u.chunk.dim[0]; u < new_dset->shared->layout.u.chunk.ndims; u++)
+                    chunk_size *= (uint64_t)new_dset->shared->layout.u.chunk.dim[u];
+
+                /* Check for chunk larger than can be represented in 32-bits */
+                /* (Chunk size is encoded in 32-bit value in v1 B-tree records) */
+                if(chunk_size > (uint64_t)0xffffffff)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "chunk size must be < 4GB")
+
+                /* Retain computed chunk size */
+                H5_ASSIGN_OVERFLOW(new_dset->shared->layout.u.chunk.size, chunk_size, uint64_t, uint32_t);
 
                 /* Initialize the chunk cache for the dataset */
                 if(H5D_istore_init(file, new_dset) < 0)
diff --git a/src/H5Distore.c b/src/H5Distore.c
index efab271..aed5add 100644
--- a/src/H5Distore.c
+++ b/src/H5Distore.c
@@ -160,7 +160,7 @@ typedef struct H5D_istore_it_ud4_t {
     H5T_path_t          *tpath_mem_dst;         /* Datatype conversion path from memory to dest. file */
     void                *reclaim_buf;           /* Buffer for reclaiming data */
     size_t              reclaim_buf_size;       /* Reclaim buffer size */
-    size_t              nelmts;                 /* Number of elements in buffer */
+    uint32_t            nelmts;                 /* Number of elements in buffer */
     H5S_t               *buf_space;             /* Dataspace describing buffer */
 
     /* needed for compressed variable-length data */
@@ -431,7 +431,7 @@ H5D_istore_debug_key(FILE *stream, H5F_t UNUSED *f, hid_t UNUSED dxpl_id, int in
 
     HDassert(key);
 
-    HDfprintf(stream, "%*s%-*s %Zd bytes\n", indent, "", fwidth, "Chunk size:", key->nbytes);
+    HDfprintf(stream, "%*s%-*s %u bytes\n", indent, "", fwidth, "Chunk size:", (unsigned)key->nbytes);
     HDfprintf(stream, "%*s%-*s 0x%08x\n", indent, "", fwidth, "Filter mask:", key->filter_mask);
     HDfprintf(stream, "%*s%-*s {", indent, "", fwidth, "Logical offset:");
     for(u = 0; u < udata->mesg->u.chunk.ndims; u++)
@@ -596,7 +596,7 @@ H5D_istore_new_node(H5F_t *f, hid_t dxpl_id, H5B_ins_t op,
 
     /* Allocate new storage */
     HDassert(udata->nbytes > 0);
-    H5_CHECK_OVERFLOW(udata->nbytes, size_t, hsize_t);
+    H5_CHECK_OVERFLOW(udata->nbytes, uint32_t, hsize_t);
     if(HADDR_UNDEF == (*addr_p = H5MF_alloc(f, H5FD_MEM_DRAW, dxpl_id, (hsize_t)udata->nbytes)))
         HGOTO_ERROR(H5E_IO, H5E_CANTINIT, FAIL, "couldn't allocate new file storage")
     udata->addr = *addr_p;
@@ -772,10 +772,10 @@ H5D_istore_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key,
                       (hsize_t)lt_key->nbytes, (hsize_t)udata->nbytes)))
                 HGOTO_ERROR(H5E_STORAGE, H5E_NOSPACE, H5B_INS_ERROR, "unable to reallocate chunk storage")
 #else /* OLD_WAY */
-            H5_CHECK_OVERFLOW( lt_key->nbytes ,size_t, hsize_t);
-            if(H5MF_xfree(f, H5FD_MEM_DRAW, dxpl_id, addr, (hsize_t)lt_key->nbytes)<0)
+            H5_CHECK_OVERFLOW(lt_key->nbytes, uint32_t, hsize_t);
+            if(H5MF_xfree(f, H5FD_MEM_DRAW, dxpl_id, addr, (hsize_t)lt_key->nbytes) < 0)
                 HGOTO_ERROR(H5E_STORAGE, H5E_CANTFREE, H5B_INS_ERROR, "unable to free chunk")
-            H5_CHECK_OVERFLOW(udata->nbytes ,size_t, hsize_t);
+            H5_CHECK_OVERFLOW(udata->nbytes, uint32_t, hsize_t);
             if(HADDR_UNDEF == (*new_node_p = H5MF_alloc(f, H5FD_MEM_DRAW, dxpl_id, (hsize_t)udata->nbytes)))
                 HGOTO_ERROR(H5E_STORAGE, H5E_NOSPACE, H5B_INS_ERROR, "unable to reallocate chunk")
 #endif /* OLD_WAY */
@@ -809,7 +809,7 @@ H5D_istore_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key,
         /*
          * Allocate storage for the new chunk
          */
-        H5_CHECK_OVERFLOW(udata->nbytes, size_t, hsize_t);
+        H5_CHECK_OVERFLOW(udata->nbytes, uint32_t, hsize_t);
         if(HADDR_UNDEF == (*new_node_p = H5MF_alloc(f, H5FD_MEM_DRAW, dxpl_id, (hsize_t)udata->nbytes)))
             HGOTO_ERROR(H5E_STORAGE, H5E_NOSPACE, H5B_INS_ERROR, "file allocation failed")
         udata->addr = *new_node_p;
@@ -874,14 +874,12 @@ H5D_istore_iter_chunkmap (H5F_t UNUSED *f, hid_t UNUSED dxpl_id, const void *_lt
 {
     H5D_istore_it_ud5_t	*udata = (H5D_istore_it_ud5_t *)_udata;
     const H5D_istore_key_t	*lt_key = (const H5D_istore_key_t *)_lt_key;
-    unsigned       rank;
+    unsigned       rank = udata->common.mesg->u.chunk.ndims - 1;
     hsize_t        chunk_index;
     int            ret_value = H5_ITER_CONT;     /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_istore_iter_chunkmap)
 
-    rank = udata->common.mesg->u.chunk.ndims - 1;
-
     if(H5V_chunk_index(rank, lt_key->offset, udata->common.mesg->u.chunk.dim, udata->down_chunks, &chunk_index) < 0)
        HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
 
@@ -968,13 +966,16 @@ H5D_istore_iter_copy(H5F_t *f_src, hid_t dxpl_id, const void *_lt_key,
     /* needed for commpressed variable length data */
     hbool_t                 is_compressed = FALSE;
     H5Z_EDC_t               edc_read = H5Z_NO_EDC;
-    size_t                  nbytes = lt_key->nbytes;
+    size_t                  nbytes;             /* Size of chunk (in bytes) */
     H5Z_cb_t                cb_struct;
 
     int                     ret_value = H5_ITER_CONT; /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_istore_iter_copy)
 
+    /* Get 'size_t' local value for number of bytes in chunk */
+    H5_ASSIGN_OVERFLOW(nbytes, lt_key->nbytes, uint32_t, size_t);
+
     /* Check parameter for type conversion */
     if(udata->do_convert) {
         if(H5T_detect_class(udata->dt_src, H5T_VLEN) > 0)
@@ -1033,12 +1034,12 @@ H5D_istore_iter_copy(H5F_t *f_src, hid_t dxpl_id, const void *_lt_key,
         hid_t                   tid_src = udata->tid_src;
         hid_t                   tid_dst = udata->tid_dst;
         hid_t                   tid_mem = udata->tid_mem;
-        size_t                  nelmts = udata->nelmts;
         void                    *reclaim_buf = udata->reclaim_buf;
         size_t                  reclaim_buf_size = udata->reclaim_buf_size;
 
         /* Convert from source file to memory */
-        if(H5T_convert(tpath_src_mem, tid_src, tid_mem, nelmts, (size_t)0, (size_t)0, buf, NULL, dxpl_id) < 0)
+        H5_CHECK_OVERFLOW(udata->nelmts, uint32_t, size_t);
+        if(H5T_convert(tpath_src_mem, tid_src, tid_mem, (size_t)udata->nelmts, (size_t)0, (size_t)0, buf, NULL, dxpl_id) < 0)
             HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, H5_ITER_ERROR, "datatype conversion failed")
 
         /* Copy into another buffer, to reclaim memory later */
@@ -1048,7 +1049,7 @@ H5D_istore_iter_copy(H5F_t *f_src, hid_t dxpl_id, const void *_lt_key,
         HDmemset(bkg, 0, buf_size);
 
         /* Convert from memory to destination file */
-        if(H5T_convert(tpath_mem_dst, tid_mem, tid_dst, nelmts, (size_t)0, (size_t)0, buf, bkg, dxpl_id) < 0)
+        if(H5T_convert(tpath_mem_dst, tid_mem, tid_dst, udata->nelmts, (size_t)0, (size_t)0, buf, bkg, dxpl_id) < 0)
             HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, H5_ITER_ERROR, "datatype conversion failed")
 
         /* Reclaim space from variable length data */
@@ -1085,7 +1086,7 @@ H5D_istore_iter_copy(H5F_t *f_src, hid_t dxpl_id, const void *_lt_key,
         if(H5Z_pipeline(pline, 0, &(udata_dst.filter_mask), edc_read,
                 cb_struct, &nbytes, &buf_size, &buf) < 0)
             HGOTO_ERROR(H5E_PLINE, H5E_CANTFILTER, H5_ITER_ERROR, "output pipeline failed")
-        udata_dst.nbytes = nbytes;
+        H5_ASSIGN_OVERFLOW(udata_dst.nbytes, nbytes, size_t, uint32_t);
 	udata->buf = buf;
 	udata->buf_size = buf_size;
     } /* end if */
@@ -1277,7 +1278,6 @@ static herr_t
 H5D_istore_flush_entry(const H5D_io_info_t *io_info, H5D_rdcc_ent_t *ent, hbool_t reset)
 {
     void		*buf = NULL;	/*temporary buffer		*/
-    size_t		alloc;		/*bytes allocated for BUF	*/
     hbool_t		point_of_no_return = FALSE;
     herr_t		ret_value = SUCCEED;	/*return value			*/
 
@@ -1292,9 +1292,6 @@ H5D_istore_flush_entry(const H5D_io_info_t *io_info, H5D_rdcc_ent_t *ent, hbool_
     if(ent->dirty) {
         H5D_istore_ud1_t 	udata;		/*pass through B-tree		*/
 
-        /* Initial buffer size */
-        alloc = ent->alloc_size;
-
         /* Set up user data for B-tree callbacks */
         udata.common.mesg = &io_info->dset->shared->layout;
         udata.common.offset = ent->offset;
@@ -1304,16 +1301,19 @@ H5D_istore_flush_entry(const H5D_io_info_t *io_info, H5D_rdcc_ent_t *ent, hbool_
 
         /* Should the chunk be filtered before writing it to disk? */
         if(io_info->dset->shared->dcpl_cache.pline.nused) {
+            size_t alloc = ent->alloc_size;	/* Bytes allocated for BUF */
+            size_t nbytes;                      /* Chunk size (in bytes) */
+
             if(!reset) {
                 /*
                  * Copy the chunk to a new buffer before running it through
                  * the pipeline because we'll want to save the original buffer
                  * for later.
                  */
-                alloc = ent->chunk_size;
+                H5_ASSIGN_OVERFLOW(alloc, ent->chunk_size, uint32_t, size_t);
                 if(NULL == (buf = H5MM_malloc(alloc)))
                     HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for pipeline")
-                HDmemcpy(buf, ent->chunk, ent->chunk_size);
+                HDmemcpy(buf, ent->chunk, alloc);
             } /* end if */
             else {
                 /*
@@ -1326,9 +1326,11 @@ H5D_istore_flush_entry(const H5D_io_info_t *io_info, H5D_rdcc_ent_t *ent, hbool_
                 point_of_no_return = TRUE;
                 ent->chunk = NULL;
             } /* end else */
+            H5_ASSIGN_OVERFLOW(nbytes, udata.nbytes, uint32_t, size_t);
             if(H5Z_pipeline(&(io_info->dset->shared->dcpl_cache.pline), 0, &(udata.filter_mask), io_info->dxpl_cache->err_detect,
-                     io_info->dxpl_cache->filter_cb, &(udata.nbytes), &alloc, &buf) < 0)
+                     io_info->dxpl_cache->filter_cb, &nbytes, &alloc, &buf) < 0)
                 HGOTO_ERROR(H5E_PLINE, H5E_CANTFILTER, FAIL, "output pipeline failed")
+            H5_ASSIGN_OVERFLOW(udata.nbytes, nbytes, size_t, uint32_t);
         } /* end if */
 
         /*
@@ -1337,7 +1339,8 @@ H5D_istore_flush_entry(const H5D_io_info_t *io_info, H5D_rdcc_ent_t *ent, hbool_
          */
         if(H5B_insert(io_info->dset->oloc.file, io_info->dxpl_id, H5B_ISTORE, io_info->dset->shared->layout.u.chunk.addr, &udata)<0)
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to allocate chunk")
-        if(H5F_block_write(io_info->dset->oloc.file, H5FD_MEM_DRAW, udata.addr, udata.nbytes, io_info->dxpl_id, buf) < 0)
+        H5_CHECK_OVERFLOW(udata.nbytes, uint32_t, size_t);
+        if(H5F_block_write(io_info->dset->oloc.file, H5FD_MEM_DRAW, udata.addr, (size_t)udata.nbytes, io_info->dxpl_id, buf) < 0)
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 
         /* Cache the chunk's info, in case it's accessed again shortly */
@@ -1688,20 +1691,20 @@ H5D_istore_prune (const H5D_io_info_t *io_info, size_t size)
     while ((p[0] || p[1]) && rdcc->nbytes+size>total) {
 
 	/* Introduce new pointers */
-	for (i=0; i<nmeth-1; i++)
-            if (0==w[i])
-                p[i+1] = rdcc->head;
+	for(i = 0; i < (nmeth - 1); i++)
+            if(0 == w[i])
+                p[i + 1] = rdcc->head;
 
 	/* Compute next value for each pointer */
-	for (i=0; i<nmeth; i++)
+	for(i = 0; i < nmeth; i++)
             n[i] = p[i] ? p[i]->next : NULL;
 
 	/* Give each method a chance */
-	for (i=0; i<nmeth && rdcc->nbytes+size>total; i++) {
-	    if (0==i && p[0] && !p[0]->locked &&
-                    ((0==p[0]->rd_count && 0==p[0]->wr_count) ||
-                     (0==p[0]->rd_count && p[0]->chunk_size==p[0]->wr_count) ||
-                     (p[0]->chunk_size==p[0]->rd_count && 0==p[0]->wr_count))) {
+	for(i = 0; i < nmeth && (rdcc->nbytes + size) > total; i++) {
+	    if(0 == i && p[0] && !p[0]->locked &&
+                    ((0 == p[0]->rd_count && 0 == p[0]->wr_count) ||
+                     (0 == p[0]->rd_count && p[0]->chunk_size == p[0]->wr_count) ||
+                     (p[0]->chunk_size == p[0]->rd_count && 0 == p[0]->wr_count))) {
 		/*
 		 * Method 0: Preempt entries that have been completely written
 		 * and/or completely read but not entries that are partially
@@ -1813,7 +1816,7 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
 
     /* Get the chunk's size */
     HDassert(layout->u.chunk.size > 0);
-    H5_ASSIGN_OVERFLOW(chunk_size, layout->u.chunk.size, hsize_t, size_t);
+    H5_ASSIGN_OVERFLOW(chunk_size, layout->u.chunk.size, uint32_t, size_t);
 
     /* Search for the chunk in the cache */
     if(rdcc->nslots > 0) {
@@ -1854,7 +1857,6 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
         /* In the case that some dataset functions look through this data,
          * clear it to all 0s. */
         HDmemset(chunk, 0, chunk_size);
-
     } /* end if */
     else {
         H5D_istore_ud1_t tmp_udata;		/*B-tree pass-through	*/
@@ -1873,24 +1875,24 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
             chunk_addr = H5D_istore_get_addr(io_info, udata);
         } /* end else */
 
-        if (H5F_addr_defined(chunk_addr)) {
-            size_t		chunk_alloc = 0;		/*allocated chunk size	*/
+        /* Check if the chunk exists on disk */
+        if(H5F_addr_defined(chunk_addr)) {
+            size_t	chunk_alloc;		/* Allocated chunk size	*/
 
-            /*
-             * The chunk exists on disk.
-             */
             /* Chunk size on disk isn't [likely] the same size as the final chunk
              * size in memory, so allocate memory big enough. */
-            chunk_alloc = udata->nbytes;
-            if(NULL == (chunk = H5D_istore_chunk_alloc (chunk_alloc, pline)))
+            H5_ASSIGN_OVERFLOW(chunk_alloc, udata->nbytes, uint32_t, size_t);
+            if(NULL == (chunk = H5D_istore_chunk_alloc(chunk_alloc, pline)))
                 HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for raw data chunk")
-            if(H5F_block_read(dset->oloc.file, H5FD_MEM_DRAW, chunk_addr, udata->nbytes, io_info->dxpl_id, chunk) < 0)
+            if(H5F_block_read(dset->oloc.file, H5FD_MEM_DRAW, chunk_addr, chunk_alloc, io_info->dxpl_id, chunk) < 0)
                 HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "unable to read raw data chunk")
 
-            if(pline->nused)
+            if(pline->nused) {
                 if(H5Z_pipeline(pline, H5Z_FLAG_REVERSE, &(udata->filter_mask), io_info->dxpl_cache->err_detect,
-                        io_info->dxpl_cache->filter_cb, &(udata->nbytes), &chunk_alloc, &chunk) < 0)
+                        io_info->dxpl_cache->filter_cb, &chunk_alloc, &chunk_alloc, &chunk) < 0)
                     HGOTO_ERROR(H5E_PLINE, H5E_CANTFILTER, NULL, "data pipeline read failed")
+                H5_ASSIGN_OVERFLOW(udata->nbytes, chunk_alloc, size_t, uint32_t);
+            } /* end if */
 #ifdef H5D_ISTORE_DEBUG
             rdcc->nmisses++;
 #endif /* H5D_ISTORE_DEBUG */
@@ -1904,7 +1906,7 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
 
             /* Chunk size on disk isn't [likely] the same size as the final chunk
              * size in memory, so allocate memory big enough. */
-            if(NULL == (chunk = H5D_istore_chunk_alloc (chunk_size, pline)))
+            if(NULL == (chunk = H5D_istore_chunk_alloc(chunk_size, pline)))
                 HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for raw data chunk")
 
             if(H5P_is_fill_value_defined(fill, &fill_status) < 0)
@@ -1947,31 +1949,31 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
          * Add the chunk to the cache only if the slot is not already locked.
          * Preempt enough things from the cache to make room.
          */
-        if (ent) {
+        if(ent) {
 #ifdef H5D_ISTORE_DEBUG
             HDputc('#', stderr);
             HDfflush(stderr);
 #endif
-            if (H5D_istore_preempt(io_info, ent, TRUE)<0)
+            if(H5D_istore_preempt(io_info, ent, TRUE) < 0)
                 HGOTO_ERROR(H5E_IO, H5E_CANTINIT, NULL, "unable to preempt chunk from cache")
-        }
-        if (H5D_istore_prune(io_info, chunk_size)<0)
+        } /* end if */
+        if(H5D_istore_prune(io_info, chunk_size) < 0)
             HGOTO_ERROR(H5E_IO, H5E_CANTINIT, NULL, "unable to preempt chunk(s) from cache")
 
         /* Create a new entry */
         ent = H5FL_MALLOC(H5D_rdcc_ent_t);
         ent->locked = 0;
         ent->dirty = FALSE;
-        ent->chunk_size = chunk_size;
+        H5_ASSIGN_OVERFLOW(ent->chunk_size, chunk_size, size_t, uint32_t);
         ent->alloc_size = chunk_size;
-        for (u=0; u<layout->u.chunk.ndims; u++)
+        for(u = 0; u < layout->u.chunk.ndims; u++)
             ent->offset[u] = io_info->store->chunk.offset[u];
-        ent->rd_count = chunk_size;
-        ent->wr_count = chunk_size;
-        ent->chunk = (uint8_t*)chunk;
+        H5_ASSIGN_OVERFLOW(ent->rd_count, chunk_size, size_t, uint32_t);
+        H5_ASSIGN_OVERFLOW(ent->wr_count, chunk_size, size_t, uint32_t);
+        ent->chunk = (uint8_t *)chunk;
 
         /* Add it to the cache */
-        assert(NULL==rdcc->slot[idx]);
+        HDassert(NULL == rdcc->slot[idx]);
         rdcc->slot[idx] = ent;
         ent->idx = idx;
         rdcc->nbytes += chunk_size;
@@ -1979,16 +1981,17 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
 
         /* Add it to the linked list */
         ent->next = NULL;
-        if (rdcc->tail) {
+        if(rdcc->tail) {
             rdcc->tail->next = ent;
             ent->prev = rdcc->tail;
             rdcc->tail = ent;
-        } else {
+        } /* end if */
+        else {
             rdcc->head = rdcc->tail = ent;
             ent->prev = NULL;
-        }
+        } /* end else */
         found = TRUE;
-    } else if (!found) {
+    } else if(!found) {
         /*
          * The chunk is larger than the entire cache so we don't cache it.
          * This is the reason all those arguments have to be repeated for the
@@ -1996,38 +1999,37 @@ H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
          */
         ent = NULL;
         idx = UINT_MAX;
-
     } else {
         /*
          * The chunk is not at the beginning of the cache; move it backward
          * by one slot.  This is how we implement the LRU preemption
          * algorithm.
          */
-        assert(ent);
-        if (ent->next) {
-            if (ent->next->next)
+        HDassert(ent);
+        if(ent->next) {
+            if(ent->next->next)
                 ent->next->next->prev = ent;
             else
                 rdcc->tail = ent;
             ent->next->prev = ent->prev;
-            if (ent->prev)
+            if(ent->prev)
                 ent->prev->next = ent->next;
             else
                 rdcc->head = ent->next;
             ent->prev = ent->next;
             ent->next = ent->next->next;
             ent->prev->next = ent;
-        }
-    }
+        } /* end if */
+    } /* end else */
 
     /* Lock the chunk into the cache */
-    if (ent) {
-        assert (!ent->locked);
+    if(ent) {
+        HDassert(!ent->locked);
         ent->locked = TRUE;
         chunk = ent->chunk;
-    }
+    } /* end if */
 
-    if (idx_hint)
+    if(idx_hint)
         *idx_hint = idx;
 
     /* Set return value */
@@ -2071,19 +2073,18 @@ done:
  */
 herr_t
 H5D_istore_unlock(const H5D_io_info_t *io_info,
-    hbool_t dirty, unsigned idx_hint, void *chunk, size_t naccessed)
+    hbool_t dirty, unsigned idx_hint, void *chunk, uint32_t naccessed)
 {
     const H5O_layout_t *layout=&(io_info->dset->shared->layout); /* Dataset layout */
     const H5D_rdcc_t	*rdcc = &(io_info->dset->shared->cache.chunk);
     H5D_rdcc_ent_t	*ent = NULL;
-    unsigned		u;
-    herr_t              ret_value=SUCCEED;      /* Return value */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_istore_unlock)
 
     assert(io_info);
 
-    if (UINT_MAX==idx_hint) {
+    if(UINT_MAX == idx_hint) {
         /*
          * It's not in the cache, probably because it's too big.  If it's
          * dirty then flush it to disk.  In any case, free the chunk.
@@ -2093,40 +2094,42 @@ H5D_istore_unlock(const H5D_io_info_t *io_info,
         if (dirty) {
             H5D_rdcc_ent_t x;
 
-            HDmemset (&x, 0, sizeof x);
+            HDmemset(&x, 0, sizeof(x));
             x.dirty = TRUE;
-            for (u=0; u<layout->u.chunk.ndims; u++)
-                x.offset[u] = io_info->store->chunk.offset[u];
-            assert(layout->u.chunk.size>0);
-            H5_ASSIGN_OVERFLOW(x.chunk_size,layout->u.chunk.size,hsize_t,size_t);
-            x.alloc_size = x.chunk_size;
-            x.chunk = (uint8_t*)chunk;
-
-            if (H5D_istore_flush_entry(io_info, &x, TRUE)<0)
+            HDassert(sizeof(x.offset[0]) == sizeof(io_info->store->chunk.offset[0]));
+            HDmemcpy(x.offset, io_info->store->chunk.offset, layout->u.chunk.ndims * sizeof(x.offset[0]));
+            HDassert(layout->u.chunk.size > 0);
+            x.chunk_size = layout->u.chunk.size;
+            H5_ASSIGN_OVERFLOW(x.alloc_size, x.chunk_size, uint32_t, size_t);
+            x.chunk = (uint8_t *)chunk;
+
+            if(H5D_istore_flush_entry(io_info, &x, TRUE) < 0)
                 HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "cannot flush indexed storage buffer")
-        } else {
+        } /* end if */
+        else {
             if(chunk)
-                chunk=H5D_istore_chunk_xfree (chunk,&(io_info->dset->shared->dcpl_cache.pline));
-        }
-    } else {
+                chunk = H5D_istore_chunk_xfree(chunk, &(io_info->dset->shared->dcpl_cache.pline));
+        } /* end else */
+    } /* end if */
+    else {
         /* Sanity check */
-	assert(idx_hint<rdcc->nslots);
-	assert(rdcc->slot[idx_hint]);
-	assert(rdcc->slot[idx_hint]->chunk==chunk);
+	HDassert(idx_hint < rdcc->nslots);
+	HDassert(rdcc->slot[idx_hint]);
+	HDassert(rdcc->slot[idx_hint]->chunk == chunk);
 
         /*
          * It's in the cache so unlock it.
          */
         ent = rdcc->slot[idx_hint];
-        assert (ent->locked);
-        if (dirty) {
+        HDassert(ent->locked);
+        if(dirty) {
             ent->dirty = TRUE;
-            ent->wr_count -= MIN (ent->wr_count, naccessed);
-        } else {
-            ent->rd_count -= MIN (ent->rd_count, naccessed);
-        }
+            ent->wr_count -= MIN(ent->wr_count, naccessed);
+        } /* end if */
+        else
+            ent->rd_count -= MIN(ent->rd_count, naccessed);
         ent->locked = FALSE;
-    }
+    } /* end else */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -2510,8 +2513,7 @@ H5D_istore_allocate(H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
 
     /* Get original chunk size */
-    H5_CHECK_OVERFLOW(layout->u.chunk.size, hsize_t, size_t);
-    orig_chunk_size = (size_t)layout->u.chunk.size;
+    H5_ASSIGN_OVERFLOW(orig_chunk_size, layout->u.chunk.size, uint32_t, size_t);
 
     /* Check the dataset's fill-value status */
     if(H5P_is_fill_value_defined(fill, &fill_status) < 0)
@@ -2613,7 +2615,7 @@ H5D_istore_allocate(H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite)
                         chunk_size = nbytes;
                     } /* end if */
                     else
-                        chunk_size = (size_t)layout->u.chunk.size;
+                        H5_ASSIGN_OVERFLOW(chunk_size, layout->u.chunk.size, uint32_t, size_t);
                 } /* end if */
                 else
                     chunk_size = orig_chunk_size;
@@ -2621,7 +2623,7 @@ H5D_istore_allocate(H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite)
                 /* Initialize the chunk information */
                 udata.common.mesg = layout;
                 udata.common.offset = chunk_offset;
-                udata.nbytes = chunk_size;
+                H5_ASSIGN_OVERFLOW(udata.nbytes, chunk_size, size_t, uint32_t);
                 udata.filter_mask = filter_mask;
                 udata.addr = HADDR_UNDEF;
 
@@ -2639,16 +2641,19 @@ H5D_istore_allocate(H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite)
                     if(using_mpi) {
                         /* Write the chunks out from only one process */
                         /* !! Use the internal "independent" DXPL!! -QAK */
-                        if(H5_PAR_META_WRITE == mpi_rank)
-                            if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.addr, udata.nbytes, data_dxpl_id, fb_info.fill_buf) < 0)
+                        if(H5_PAR_META_WRITE == mpi_rank) {
+                            HDassert(udata.nbytes == chunk_size);
+                            if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.addr, chunk_size, data_dxpl_id, fb_info.fill_buf) < 0)
                                 HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
+                        } /* end if */
 
                         /* Indicate that blocks are being written */
                         blocks_written = TRUE;
                     } /* end if */
                     else {
 #endif /* H5_HAVE_PARALLEL */
-                        if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.addr, udata.nbytes, data_dxpl_id, fb_info.fill_buf) < 0)
+                        HDassert(udata.nbytes == chunk_size);
+                        if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.addr, chunk_size, data_dxpl_id, fb_info.fill_buf) < 0)
                             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 #ifdef H5_HAVE_PARALLEL
                     } /* end else */
@@ -3029,12 +3034,13 @@ H5D_istore_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key /*in,out
 	hbool_t *rt_key_changed /*out */ )
 {
     H5D_istore_key_t    *lt_key = (H5D_istore_key_t *)_lt_key;
-    H5B_ins_t ret_value=H5B_INS_REMOVE; /* Return value */
+    H5B_ins_t ret_value = H5B_INS_REMOVE;       /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_istore_remove)
 
     /* Remove raw data chunk from file */
-    if(H5MF_xfree(f, H5FD_MEM_DRAW, dxpl_id, addr, (hsize_t)lt_key->nbytes)<0)
+    H5_CHECK_OVERFLOW(lt_key->nbytes, uint32_t, hsize_t);
+    if(H5MF_xfree(f, H5FD_MEM_DRAW, dxpl_id, addr, (hsize_t)lt_key->nbytes) < 0)
         HGOTO_ERROR(H5E_STORAGE, H5E_CANTFREE, H5B_INS_ERROR, "unable to free chunk")
 
     /* Mark keys as unchanged */
@@ -3082,7 +3088,7 @@ H5D_istore_initialize_by_extent(H5D_io_info_t *io_info)
     hsize_t          hyper_start[H5O_LAYOUT_NDIMS];	/* Starting location of hyperslab */
     hsize_t          nchunks[H5O_LAYOUT_NDIMS]; /* Current number of chunks in each dimension */
     hsize_t          down_chunks[H5O_LAYOUT_NDIMS]; /* "down" size of number of elements in each dimension */
-    hsize_t          bytes_per_chunk;	/* Bytes in chunk */
+    uint32_t         elmts_per_chunk;	/* Elements in a chunk */
     int              srank;	        /* # of chunk dimensions (signed) */
     unsigned         rank;	        /* # of chunk dimensions */
     hbool_t	     carry;             /* Flag to indicate that chunk increment carrys to higher dimension (sorta) */
@@ -3105,11 +3111,11 @@ H5D_istore_initialize_by_extent(H5D_io_info_t *io_info)
     /* Set size of lowest chunk dimension (the dataset element size) */
     dset_dims[rank] = layout->u.chunk.dim[rank];
 
-    /* Compute the number of chunks in dataset & the # of bytes in a chunk */
+    /* Compute the number of chunks in dataset & the # of elements in a chunk */
     /* (round up to the next integer # of chunks, to accomodate partial chunks) */
-    for(u = 0, bytes_per_chunk = layout->u.chunk.dim[rank]; u < rank; u++) {
+    for(u = 0, elmts_per_chunk = 1; u < rank; u++) {
         nchunks[u] = ((dset_dims[u] - 1) / layout->u.chunk.dim[u]) + 1;
-        bytes_per_chunk *= layout->u.chunk.dim[u];
+        elmts_per_chunk *= layout->u.chunk.dim[u];
     } /* end for */
 
     /* Get the "down" sizes for each dimension */
@@ -3159,9 +3165,10 @@ H5D_istore_initialize_by_extent(H5D_io_info_t *io_info)
 
             /* Initialize the fill value buffer, if necessary */
             if(!fb_info_init) {
+                H5_CHECK_OVERFLOW(elmts_per_chunk, uint32_t, size_t);
                 if(H5D_fill_init(&fb_info, NULL, FALSE, NULL, NULL, NULL, NULL,
                         &dset->shared->dcpl_cache.fill,
-                        dset->shared->type, dset->shared->type_id, (size_t)(bytes_per_chunk / layout->u.chunk.dim[rank]),
+                        dset->shared->type, dset->shared->type_id, (size_t)elmts_per_chunk,
                         io_info->dxpl_cache->max_temp_buf, io_info->dxpl_id) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize fill buffer info")
                 fb_info_init = TRUE;
@@ -3217,7 +3224,8 @@ H5D_istore_initialize_by_extent(H5D_io_info_t *io_info)
                     HGOTO_ERROR(H5E_DATASET, H5E_CANTCONVERT, FAIL, "can't refill fill value buffer")
 
             /* Create a selection iterator for scattering the elements to memory buffer */
-            if(H5S_select_iter_init(&chunk_iter, space_chunk, layout->u.chunk.dim[rank]) < 0)
+            H5_CHECK_OVERFLOW(layout->u.chunk.dim[rank], uint32_t, size_t);
+            if(H5S_select_iter_init(&chunk_iter, space_chunk, (size_t)layout->u.chunk.dim[rank]) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize chunk selection information")
 
             /* Scatter the data into memory */
@@ -3236,8 +3244,8 @@ H5D_istore_initialize_by_extent(H5D_io_info_t *io_info)
             bytes_accessed = nelmts * layout->u.chunk.dim[rank];
 
             /* Release lock on chunk */
-            H5_CHECK_OVERFLOW(bytes_accessed, hsize_t, size_t);
-	    if(H5D_istore_unlock(io_info, TRUE, idx_hint, chunk, (size_t)bytes_accessed) < 0)
+            H5_CHECK_OVERFLOW(bytes_accessed, hsize_t, uint32_t);
+	    if(H5D_istore_unlock(io_info, TRUE, idx_hint, chunk, (uint32_t)bytes_accessed) < 0)
 		HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to unlock raw data chunk")
 	} /* end if */
 
@@ -3386,12 +3394,12 @@ H5D_istore_update_cache(H5D_t *dset, hid_t dxpl_id)
         next = ent->next;
 
         /* Calculate the index of this chunk */
-        if(H5V_chunk_index(rank,ent->offset,dset->shared->layout.u.chunk.dim,down_chunks,&idx)<0)
+        if(H5V_chunk_index(rank, ent->offset, dset->shared->layout.u.chunk.dim, down_chunks, &idx) < 0)
             HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "can't get chunk index")
 
         /* Compute the index for the chunk entry */
-        old_idx=ent->idx;   /* Save for later */
-        ent->idx=H5D_CHUNK_HASH(dset->shared, idx);
+        old_idx = ent->idx;   /* Save for later */
+        ent->idx = H5D_CHUNK_HASH(dset->shared, idx);
 
         if(old_idx != ent->idx) {
             /* Check if there is already a chunk at this chunk's new location */
@@ -3450,7 +3458,7 @@ H5D_istore_copy(H5F_t *f_src, H5O_layout_t *layout_src, H5F_t *f_dst,
     void       *reclaim_buf = NULL;     /* Buffer for reclaiming data */
     H5S_t      *buf_space = NULL;       /* Dataspace describing buffer */
     hid_t       sid_buf = -1;           /* ID for buffer dataspace */
-    size_t      nelmts = 0;             /* Number of elements in buffer */
+    uint32_t    nelmts = 0;             /* Number of elements in buffer */
     hbool_t     do_convert = FALSE;     /* Indicate that type conversions should be performed */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -3553,7 +3561,7 @@ H5D_istore_copy(H5F_t *f_src, H5O_layout_t *layout_src, H5F_t *f_dst,
             do_convert = TRUE;
         } /* end if */
 
-        buf_size = layout_src->u.chunk.size;
+        H5_ASSIGN_OVERFLOW(buf_size, layout_src->u.chunk.size, uint32_t, size_t);
         reclaim_buf_size = 0;
     } /* end else */
 
diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index 889fbce..dd0c602 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -1183,7 +1183,7 @@ if(H5DEBUG(D))
                 H5D_io_info_t *chk_io_info;     /* Pointer to I/O info object for this chunk */
                 H5D_istore_ud1_t udata;         /* B-tree pass-through	*/
                 void *chunk;                    /* Pointer to the data chunk in cache */
-                size_t accessed_bytes;          /* Total accessed size in a chunk */
+                uint32_t accessed_bytes;          /* Total accessed size in a chunk */
                 unsigned idx_hint = 0;          /* Cache index hint      */
                 haddr_t caddr;                  /* Address of the cached chunk */
 
@@ -1203,9 +1203,11 @@ if(H5DEBUG(D))
                 /* Load the chunk into cache and lock it. */
                 if(H5D_chunk_cacheable(io_info, caddr)) {
                     hbool_t entire_chunk = TRUE;         /* Whether whole chunk is selected */
+                    size_t tmp_accessed_bytes;           /* Total accessed size in a chunk */
 
                     /* Compute # of bytes accessed in chunk */
-                    accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                    tmp_accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                    H5_ASSIGN_OVERFLOW(accessed_bytes, tmp_accessed_bytes, size_t, uint32_t);
 
                     /* Determine if we will access all the data in the chunk */
                     if(((io_info->op_type == H5D_IO_OP_WRITE) && (accessed_bytes != ctg_store.contig.dset_size))
@@ -1419,7 +1421,7 @@ if(H5DEBUG(D)) {
         if(make_ind) {
             void *chunk;                /* Pointer to the data chunk in cache */
             H5D_io_info_t *chk_io_info;     /* Pointer to I/O info object for this chunk */
-            size_t accessed_bytes = 0;  /* Total accessed size in a chunk */
+            uint32_t accessed_bytes = 0;  /* Total accessed size in a chunk */
             unsigned idx_hint = 0;      /* Cache index hint      */
 
             /* Switch to independent I/O */
@@ -1429,9 +1431,11 @@ if(H5DEBUG(D)) {
             /* Load the chunk into cache and lock it. */
             if(H5D_chunk_cacheable(io_info, chunk_addr)) {
                 hbool_t entire_chunk = TRUE;         /* Whether whole chunk is selected */
+                size_t tmp_accessed_bytes;           /* Total accessed size in a chunk */
 
                 /* Compute # of bytes accessed in chunk */
-                accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                tmp_accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
+                H5_ASSIGN_OVERFLOW(accessed_bytes, tmp_accessed_bytes, size_t, uint32_t);
 
                 /* Determine if we will access all the data in the chunk */
                 if(((io_info->op_type == H5D_IO_OP_WRITE) && (accessed_bytes != ctg_store.contig.dset_size))
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 97dcacf..1b20ad8 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -204,7 +204,7 @@ typedef struct H5D_io_info_t {
 /* Structure holding information about a chunk's selection for mapping */
 typedef struct H5D_chunk_info_t {
     hsize_t index;              /* "Index" of chunk in dataset */
-    size_t chunk_points;        /* Number of elements selected in chunk */
+    uint32_t chunk_points;      /* Number of elements selected in chunk */
     hsize_t coords[H5O_LAYOUT_NDIMS];   /* Coordinates of chunk in file dataset's dataspace */
     H5S_t *fspace;              /* Dataspace describing chunk & selection in it */
     unsigned fspace_shared;     /* Indicate that the file space for a chunk is shared and shouldn't be freed */
@@ -213,10 +213,10 @@ typedef struct H5D_chunk_info_t {
 } H5D_chunk_info_t;
 
 /* Cached information about a particular chunk */
-typedef struct {
+typedef struct H5D_chunk_cached_t{
     hbool_t     valid;                          /*whether cache info is valid*/
     hsize_t	offset[H5O_LAYOUT_NDIMS];	/*logical offset to start*/
-    size_t	nbytes;				/*size of stored data	*/
+    uint32_t	nbytes;				/*size of stored data	*/
     unsigned	filter_mask;			/*excluded filters	*/
     haddr_t	addr;				/*file address of chunk */
 } H5D_chunk_cached_t;
@@ -379,7 +379,7 @@ typedef struct {
  * The chunk's file address is part of the B-tree and not part of the key.
  */
 typedef struct H5D_istore_key_t {
-    size_t	nbytes;				/*size of stored data	*/
+    uint32_t	nbytes;				/*size of stored data	*/
     hsize_t	offset[H5O_LAYOUT_NDIMS];	/*logical offset to start*/
     unsigned	filter_mask;			/*excluded filters	*/
 } H5D_istore_key_t;
@@ -401,7 +401,7 @@ typedef struct H5D_istore_ud1_t {
     H5D_istore_bt_ud_common_t common;           /* Common info for B-tree user data (must be first) */
 
     /* Upward */
-    size_t	nbytes;				/*size of stored data	*/
+    uint32_t	nbytes;				/*size of stored data	*/
     unsigned	filter_mask;			/*excluded filters	*/
     haddr_t	addr;				/*file address of chunk */
 } H5D_istore_ud1_t; 
@@ -422,9 +422,9 @@ typedef struct H5D_rdcc_ent_t {
     hbool_t	locked;		/*entry is locked in cache		*/
     hbool_t	dirty;		/*needs to be written to disk?		*/
     hsize_t	offset[H5O_LAYOUT_NDIMS]; /*chunk name			*/
-    size_t	rd_count;	/*bytes remaining to be read		*/
-    size_t	wr_count;	/*bytes remaining to be written		*/
-    size_t	chunk_size;	/*size of a chunk			*/
+    uint32_t	rd_count;	/*bytes remaining to be read		*/
+    uint32_t	wr_count;	/*bytes remaining to be written		*/
+    uint32_t	chunk_size;	/*size of a chunk			*/
     size_t	alloc_size;	/*amount allocated for the chunk	*/
     uint8_t	*chunk;		/*the unfiltered chunk data		*/
     unsigned	idx;		/*index in hash table			*/
@@ -547,7 +547,7 @@ H5_DLL herr_t H5D_istore_copy(H5F_t *f_src, H5O_layout_t *layout_src,
 H5_DLL void * H5D_istore_lock(const H5D_io_info_t *io_info, H5D_istore_ud1_t *udata,
     hbool_t relax, unsigned *idx_hint/*in,out*/);
 H5_DLL herr_t H5D_istore_unlock(const H5D_io_info_t *io_info,
-    hbool_t dirty, unsigned idx_hint, void *chunk, size_t naccessed);
+    hbool_t dirty, unsigned idx_hint, void *chunk, uint32_t naccessed);
 
 /* Functions that perform fill value operations on datasets */
 H5_DLL herr_t H5D_fill(const void *fill, const H5T_t *fill_type, void *buf,
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 4a55ac2..3c5204f 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -334,8 +334,8 @@ typedef struct H5O_layout_contig_t {
 typedef struct H5O_layout_chunk_t {
     haddr_t	addr;			/* File address of B-tree            */
     unsigned	ndims;			/* Num dimensions in chunk           */
-    size_t	dim[H5O_LAYOUT_NDIMS];	/* Size of chunk in elements         */
-    size_t      size;                   /* Size of chunk in bytes            */
+    uint32_t	dim[H5O_LAYOUT_NDIMS];	/* Size of chunk in elements         */
+    uint32_t    size;                   /* Size of chunk in bytes            */
     H5RC_t     *btree_shared;           /* Ref-counted info for B-tree nodes */
 } H5O_layout_chunk_t;
 
diff --git a/src/H5Pdcpl.c b/src/H5Pdcpl.c
index 8d6b9ab..9501019 100644
--- a/src/H5Pdcpl.c
+++ b/src/H5Pdcpl.c
@@ -55,7 +55,7 @@
 #define H5D_CRT_CHUNK_DIM_SIZE     sizeof(unsigned)
 #define H5D_CRT_CHUNK_DIM_DEF      1
 /* Definitions for chunk size */
-#define H5D_CRT_CHUNK_SIZE_SIZE    sizeof(size_t[H5O_LAYOUT_NDIMS])
+#define H5D_CRT_CHUNK_SIZE_SIZE    sizeof(uint32_t[H5O_LAYOUT_NDIMS])
 #define H5D_CRT_CHUNK_SIZE_DEF     {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,\
                                    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
 /* Definitions for fill value.  size=0 means fill value will be 0 as
@@ -148,7 +148,7 @@ H5P_dcrt_reg_prop(H5P_genclass_t *pclass)
 {
     H5D_layout_t layout = H5D_CRT_LAYOUT_DEF;           /* Default storage layout */
     unsigned chunk_ndims = H5D_CRT_CHUNK_DIM_DEF;       /* Default rank for chunks */
-    size_t chunk_size[H5O_LAYOUT_NDIMS] = H5D_CRT_CHUNK_SIZE_DEF;       /* Default chunk size */
+    uint32_t chunk_size[H5O_LAYOUT_NDIMS] = H5D_CRT_CHUNK_SIZE_DEF;       /* Default chunk size */
     H5O_fill_t fill = H5D_CRT_FILL_VALUE_DEF;           /* Default fill value */
     unsigned alloc_time_state = H5D_CRT_ALLOC_TIME_STATE_DEF;   /* Default allocation time state */
     H5O_efl_t efl = H5D_CRT_EXT_FILE_LIST_DEF;          /* Default external file list */
@@ -737,37 +737,43 @@ done:
 herr_t
 H5Pset_chunk(hid_t plist_id, int ndims, const hsize_t dim[/*ndims*/])
 {
-    int			    i;
-    size_t real_dims[H5O_LAYOUT_NDIMS]; /* Full-sized array to hold chunk dims */
     H5P_genplist_t *plist;      /* Property list pointer */
-    herr_t ret_value=SUCCEED;   /* return value */
+    uint32_t real_dims[H5O_LAYOUT_NDIMS]; /* Full-sized array to hold chunk dims */
+    uint64_t chunk_nelmts;      /* Number of elements in chunk */
+    unsigned u;                 /* Local index variable */
+    herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(H5Pset_chunk, FAIL)
     H5TRACE3("e", "iIs*[a1]h", plist_id, ndims, dim);
 
     /* Check arguments */
-    if (ndims <= 0)
+    if(ndims <= 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "chunk dimensionality must be positive")
-    if (ndims > H5S_MAX_RANK)
+    if(ndims > H5S_MAX_RANK)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "chunk dimensionality is too large")
-    if (!dim)
+    if(!dim)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no chunk dimensions specified")
 
-    /* Get the plist structure */
-    if(NULL == (plist = H5P_object_verify(plist_id,H5P_DATASET_CREATE)))
-        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
-
-    /* Initialize chunk dims to 0s */
-    HDmemset(real_dims,0,sizeof(real_dims));
-    for (i=0; i<ndims; i++) {
-        if (dim[i] == 0)
+    /* Verify & initialize internal chunk dims */
+    HDmemset(real_dims, 0, sizeof(real_dims));
+    chunk_nelmts = 1;
+    for(u = 0; u < (unsigned)ndims; u++) {
+        if(dim[u] == 0)
             HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "all chunk dimensions must be positive")
-        if (dim[i] != (dim[i]&0xffffffff))
+        if(dim[u] != (dim[u] & 0xffffffff))
             HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "all chunk dimensions must be less than 2^32")
-        real_dims[i]=(size_t)dim[i]; /* Store user's chunk dimensions */
+        chunk_nelmts *= dim[u];
+        if(chunk_nelmts > (uint64_t)0xffffffff)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "number of elements in chunk must be < 4GB")
+        real_dims[u] = (uint32_t)dim[u]; /* Store user's chunk dimensions */
     } /* end for */
 
-    if(H5P_set_layout (plist, H5D_CHUNKED) < 0)
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_DATASET_CREATE)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Set chunk information in property list */
+    if(H5P_set_layout(plist, H5D_CHUNKED) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set layout")
     if(H5P_set(plist, H5D_CRT_CHUNK_DIM_NAME, &ndims) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set chunk dimensionanlity")
@@ -776,7 +782,7 @@ H5Pset_chunk(hid_t plist_id, int ndims, const hsize_t dim[/*ndims*/])
 
 done:
     FUNC_LEAVE_API(ret_value)
-}
+} /* end H5Pset_chunk() */
 
 
 /*-------------------------------------------------------------------------
@@ -828,22 +834,22 @@ H5Pget_chunk(hid_t plist_id, int max_ndims, hsize_t dim[]/*out*/)
 
     if(dim) {
         int		i;
-        size_t          chunk_size[H5O_LAYOUT_NDIMS];
+        uint32_t        chunk_size[H5O_LAYOUT_NDIMS];
 
         if(H5P_get(plist, H5D_CRT_CHUNK_SIZE_NAME, chunk_size) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get chunk size")
 
         /* Get the dimension sizes */
-        for (i=0; i<ndims && i<max_ndims; i++)
+        for(i = 0; i < ndims && i < max_ndims; i++)
             dim[i] = chunk_size[i];
     } /* end if */
 
     /* Set the return value */
-    ret_value=ndims;
+    ret_value = ndims;
 
 done:
     FUNC_LEAVE_API(ret_value)
-}
+} /* end H5Pget_chunk() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5V.c b/src/H5V.c
index 3e06636..34cf714 100644
--- a/src/H5V.c
+++ b/src/H5V.c
@@ -399,33 +399,34 @@ done:
  */
 htri_t
 H5V_hyper_disjointp(unsigned n,
-		    const hsize_t *offset1, const size_t *size1,
-		    const hsize_t *offset2, const size_t *size2)
+    const hsize_t *offset1, const uint32_t *size1,
+    const hsize_t *offset2, const uint32_t *size2)
 {
     unsigned	u;
-    htri_t      ret_value=FALSE;        /* Return value */
+    htri_t      ret_value = FALSE;        /* Return value */
 
     /* Use FUNC_ENTER_NOAPI_NOINIT_NOFUNC here to avoid performance issues */
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5V_hyper_disjointp)
 
-    if (!n || !size1 || !size2)	HGOTO_DONE(TRUE)
+    if(!n || !size1 || !size2)
+        HGOTO_DONE(TRUE)
 
-    for (u=0; u<n; u++) {
-        assert (size1[u]<HSIZET_MAX);
-        assert (size2[u]<HSIZET_MAX);
+    for(u = 0; u < n; u++) {
+        HDassert(size1[u] < HSIZET_MAX);
+        HDassert(size2[u] < HSIZET_MAX);
 
-        if (0==size1[u] || 0==size2[u])
+        if(0 == size1[u] || 0 == size2[u])
             HGOTO_DONE(TRUE)
-        if (((offset1?offset1[u]:0) < (offset2?offset2[u]:0) &&
-             ((offset1?offset1[u]:0) + size1[u] <= (offset2?offset2[u]:0))) ||
-            ((offset2?offset2[u]:0) < (offset1?offset1[u]:0) &&
-             ((offset2?offset2[u]:0) + size2[u] <= (offset1?offset1[u]:0))))
+        if(((offset1 ? offset1[u] : 0) < (offset2 ? offset2[u] : 0) &&
+                    ((offset1 ? offset1[u] : 0) + size1[u] <= (offset2 ? offset2[u] : 0))) ||
+                ((offset2 ? offset2[u] : 0) < (offset1 ? offset1[u] : 0) &&
+                    ((offset2 ? offset2[u] : 0) + size2[u] <= (offset1 ? offset1[u] : 0))))
             HGOTO_DONE(TRUE)
-    }
+    } /* end for */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5V_hyper_disjointp() */
 
 
 /*-------------------------------------------------------------------------
@@ -1225,7 +1226,7 @@ H5V_array_calc(hsize_t offset, unsigned n, const hsize_t *total_size, hsize_t *c
  *-------------------------------------------------------------------------
  */
 herr_t
-H5V_chunk_index(unsigned ndims, const hsize_t *coord, const size_t *chunk,
+H5V_chunk_index(unsigned ndims, const hsize_t *coord, const uint32_t *chunk,
     const hsize_t *down_nchunks, hsize_t *chunk_idx)
 {
     hsize_t	scaled_coord[H5V_HYPER_NDIMS];	/* Scaled, coordinates, in terms of chunks */
diff --git a/src/H5Vprivate.h b/src/H5Vprivate.h
index b92266c..e562880 100644
--- a/src/H5Vprivate.h
+++ b/src/H5Vprivate.h
@@ -53,9 +53,7 @@ H5_DLL hsize_t H5V_hyper_stride(unsigned n, const hsize_t *size,
 				 const hsize_t *offset,
 				 hsize_t *stride);
 H5_DLL htri_t H5V_hyper_disjointp(unsigned n, const hsize_t *offset1,
-				   const size_t *size1,
-				   const hsize_t *offset2,
-				   const size_t *size2);
+    const uint32_t *size1, const hsize_t *offset2, const uint32_t *size2);
 H5_DLL htri_t H5V_hyper_eq(unsigned n, const hsize_t *offset1,
 			    const hsize_t *size1, const hsize_t *offset2,
 			    const hsize_t *size2);
@@ -88,7 +86,7 @@ H5_DLL hsize_t H5V_array_offset(unsigned n, const hsize_t *total_size,
 H5_DLL herr_t H5V_array_calc(hsize_t offset, unsigned n,
     const hsize_t *total_size, hsize_t *coords);
 H5_DLL herr_t H5V_chunk_index(unsigned ndims, const hsize_t *coord,
-    const size_t *chunk, const hsize_t *down_nchunks, hsize_t *chunk_idx);
+    const uint32_t *chunk, const hsize_t *down_nchunks, hsize_t *chunk_idx);
 H5_DLL ssize_t H5V_memcpyvv(void *_dst,
     size_t dst_max_nseq, size_t *dst_curr_seq, size_t dst_len_arr[], hsize_t dst_off_arr[],
     const void *_src,
diff --git a/test/Makefile.am b/test/Makefile.am
index 9dbb0cf..a3f8660 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -104,7 +104,7 @@ flush2.chkexe_: flush1.chkexe_
 # the temporary file name in ways that the makefile is not aware of.
 CHECK_CLEANFILES+=cmpd_dset.h5 compact_dataset.h5 dataset.h5 dset_offset.h5 \
             max_compact_dataset.h5 simple.h5 set_local.h5 random_chunks.h5 \
-            extend.h5 istore.h5 \
+            huge_chunks.h5 extend.h5 istore.h5 \
             tfile[1-4].h5 th5s[1-3].h5 lheap.h5 fheap.h5 ohdr.h5 stab.h5 \
             extern_[1-3].h5 extern_[1-4][ab].raw gheap[0-4].h5 dt_arith[1-2] \
             links.h5 links[0-6]*.h5 extlinks[0-15].h5 tmp \
diff --git a/test/dsets.c b/test/dsets.c
index e5fa5b5..8edc2d2 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -42,6 +42,7 @@ const char *FILENAME[] = {
     "simple",
     "set_local",
     "random_chunks",
+    "huge_chunks",
     NULL
 };
 #define FILENAME_BUF_SIZE       1024
@@ -145,6 +146,22 @@ const char *FILENAME[] = {
 /* Names for random chunks test */
 #define NPOINTS         50
 
+/* Parameters for huge chunks test */
+#define HUGE_DATASET            "Dataset"
+#define HUGE_DIM                ((hsize_t)16 * 1024 * 1024 * 1024)
+#define HUGE_CHUNK_DIM          ((hsize_t)2 * 1024 * 1024 * 1024)
+#define TOO_HUGE_CHUNK_DIM      ((hsize_t)4 * 1024 * 1024 * 1024)
+#define HUGE_DATASET2           "Dataset2"
+#define HUGE_DIM2_0             ((hsize_t)16 * 1024)
+#define HUGE_DIM2_1             ((hsize_t)16 * 1024)
+#define HUGE_DIM2_2             ((hsize_t)16 * 1024)
+#define HUGE_CHUNK_DIM2_0       ((hsize_t)2 * 1024)
+#define HUGE_CHUNK_DIM2_1       ((hsize_t)1024)
+#define HUGE_CHUNK_DIM2_2       ((hsize_t)1024)
+#define TOO_HUGE_CHUNK_DIM2_0   ((hsize_t)4 * 1024)
+#define TOO_HUGE_CHUNK_DIM2_1   ((hsize_t)1024)
+#define TOO_HUGE_CHUNK_DIM2_2   ((hsize_t)1024)
+
 /* Shared global arrays */
 #define DSET_DIM1       100
 #define DSET_DIM2       200
@@ -1941,8 +1958,6 @@ UNUSED
     data_corrupt[1] = 33;
     data_corrupt[2] = 27;
 
-    /* Temporarily disable this test because the changes in chunk caching conflicts with
-     * the way this test is conducted. -slu 2007/7/20 */
     if(H5Zregister (H5Z_CORRUPT) < 0) goto error;
     if(H5Pset_filter(dc, H5Z_FILTER_CORRUPT, 0, (size_t)3, data_corrupt) < 0) goto error;
     if(test_filter_internal(file,DSET_FLETCHER32_NAME_3,dc,DISABLE_FLETCHER32,DATA_CORRUPTED,&fletcher32_size) < 0) goto error;
@@ -6359,6 +6374,118 @@ test_deprec(hid_t file)
 
 
 /*-------------------------------------------------------------------------
+ * Function: test_huge_chunks
+ *
+ * Purpose: Tests that datasets with chunks >4GB can't be created.
+ *
+ * Return:      Success: 0
+ *              Failure: -1
+ *
+ * Programmer:  Quincey Koziol
+ *              Thursday, May  1, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+test_huge_chunks(hid_t fapl)
+{
+    char        filename[FILENAME_BUF_SIZE];
+    hid_t       fid = -1;       /* File ID */
+    hid_t       dcpl = -1;      /* Dataset creation property list ID */
+    hid_t       sid = -1;       /* Dataspace ID */
+    hid_t       dsid = -1;      /* Dataset ID */
+    hsize_t     dim, chunk_dim; /* Dataset and chunk dimensions */
+    hsize_t     dim2[3], chunk_dim2[3];  /* Dataset and chunk dimensions */
+    herr_t      ret;            /* Generic return value */
+
+    TESTING("creating dataset with >4GB chunks");
+
+    h5_fixname(FILENAME[7], fapl, filename, sizeof filename);
+
+    /* Create file */
+    if((fid = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0) FAIL_STACK_ERROR
+
+    /* Create dataset creation property list */
+    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0) FAIL_STACK_ERROR
+
+    /* Try to set too large of a chunk for 1-D dataset (# of elements) */
+    chunk_dim = TOO_HUGE_CHUNK_DIM;
+    H5E_BEGIN_TRY {
+        ret = H5Pset_chunk(dcpl, 1, &chunk_dim);
+    } H5E_END_TRY;
+    if(ret >= 0)
+	FAIL_PUTS_ERROR("    Set chunk size with too large of chunk dimensions.")
+
+    /* Try to set too large of a chunk for n-D dataset (# of elements) */
+    chunk_dim2[0] = TOO_HUGE_CHUNK_DIM2_0;
+    chunk_dim2[1] = TOO_HUGE_CHUNK_DIM2_1;
+    chunk_dim2[2] = TOO_HUGE_CHUNK_DIM2_2;
+    H5E_BEGIN_TRY {
+        ret = H5Pset_chunk(dcpl, 3, chunk_dim2);
+    } H5E_END_TRY;
+    if(ret >= 0)
+	FAIL_PUTS_ERROR("    Set chunk size with too large of chunk dimensions.")
+
+    /* Set 1-D chunk size */
+    chunk_dim = HUGE_CHUNK_DIM;
+    if(H5Pset_chunk(dcpl, 1, &chunk_dim) < 0) FAIL_STACK_ERROR
+
+    /* Create 1-D dataspace */
+    dim = HUGE_DIM;
+    if((sid = H5Screate_simple(1, &dim, NULL)) < 0) FAIL_STACK_ERROR
+
+    /* Try to create dataset */
+    H5E_BEGIN_TRY {
+        dsid = H5Dcreate2(fid, HUGE_DATASET, H5T_NATIVE_INT, sid, H5P_DEFAULT, dcpl, H5P_DEFAULT);
+    } H5E_END_TRY;
+    if(dsid >= 0)
+	FAIL_PUTS_ERROR("    1-D Dataset with too large of chunk dimensions created.")
+
+    /* Close 1-D dataspace */
+    if(H5Sclose(sid) < 0) FAIL_STACK_ERROR
+
+
+    /* Set n-D chunk size */
+    chunk_dim2[0] = HUGE_CHUNK_DIM2_0;
+    chunk_dim2[1] = HUGE_CHUNK_DIM2_1;
+    chunk_dim2[2] = HUGE_CHUNK_DIM2_2;
+    if(H5Pset_chunk(dcpl, 3, chunk_dim2) < 0) FAIL_STACK_ERROR
+
+    /* Create n-D dataspace */
+    dim2[0] = HUGE_DIM2_0;
+    dim2[1] = HUGE_DIM2_1;
+    dim2[2] = HUGE_DIM2_2;
+    if((sid = H5Screate_simple(3, dim2, NULL)) < 0) FAIL_STACK_ERROR
+
+    /* Try to create dataset */
+    H5E_BEGIN_TRY {
+        dsid = H5Dcreate2(fid, HUGE_DATASET2, H5T_NATIVE_INT, sid, H5P_DEFAULT, dcpl, H5P_DEFAULT);
+    } H5E_END_TRY;
+    if(dsid >= 0)
+	FAIL_PUTS_ERROR("    n-D Dataset with too large of chunk dimensions created.")
+
+    /* Close n-D dataspace */
+    if(H5Sclose(sid) < 0) FAIL_STACK_ERROR
+
+    /* Close everything else */
+    if(H5Pclose(dcpl) < 0) FAIL_STACK_ERROR
+    if(H5Fclose(fid) < 0) FAIL_STACK_ERROR
+
+    PASSED();
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Pclose(dcpl);
+        H5Dclose(dsid);
+        H5Sclose(sid);
+        H5Fclose(fid);
+    } H5E_END_TRY;
+    return -1;
+} /* end test_huge_chunks() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	main
  *
  * Purpose:	Tests the dataset interface (H5D)
@@ -6393,12 +6520,19 @@ main(void)
         size_t rdcc_nbytes;
         double rdcc_w0;
 
+	/* Set the random # seed */
+	HDsrandom((unsigned long)HDtime(NULL));
+
 	/* Testing setup */
 	h5_reset();
 	fapl = h5_fileaccess();
 
-	/* Set the random # seed */
-	HDsrandom((unsigned long)HDtime(NULL));
+        /* Turn off the chunk cache, so all the chunks are immediately written to disk */
+        if(H5Pget_cache(fapl, &mdc_nelmts, &rdcc_nelmts, &rdcc_nbytes, &rdcc_w0) < 0)
+            goto error;
+        rdcc_nbytes = 0;
+        if(H5Pset_cache(fapl, mdc_nelmts, rdcc_nelmts, rdcc_nbytes, rdcc_w0) < 0)
+            goto error;
 
         /* Copy the file access property list */
         if((fapl2 = H5Pcopy(fapl)) < 0) TEST_ERROR
@@ -6422,13 +6556,6 @@ main(void)
                 my_fapl = fapl;
             } /* end else */
 
-            /* Turn off the chunk cache, so all the chunks are immediately written to disk */
-            if(H5Pget_cache(my_fapl, &mdc_nelmts, &rdcc_nelmts, &rdcc_nbytes, &rdcc_w0) < 0)
-                goto error;
-            rdcc_nbytes = 0;
-            if(H5Pset_cache(my_fapl, mdc_nelmts, rdcc_nelmts, rdcc_nbytes, rdcc_w0) < 0)
-                goto error;
-
             /* Create the file for this test */
             if((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, my_fapl)) < 0)
                 goto error;
@@ -6478,6 +6605,7 @@ main(void)
 #ifndef H5_NO_DEPRECATED_SYMBOLS
             nerrors += (test_deprec(file) < 0			? 1 : 0);
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
+            nerrors += (test_huge_chunks(my_fapl) < 0		? 1 : 0);
             
             if(H5Fclose(file) < 0)
                 goto error;
diff --git a/test/istore.c b/test/istore.c
index dfe5c41..e0d2e82 100644
--- a/test/istore.c
+++ b/test/istore.c
@@ -171,19 +171,20 @@ test_create(hid_t f, const char *prefix)
 {
     hid_t       dataset;        /* Dataset ID */
     hsize_t     dims[H5O_LAYOUT_NDIMS+1]; /* Dimensions of dataset */
+    hsize_t     my_chunk_dims[H5O_LAYOUT_NDIMS+1]; /* Dimensions of chunks */
     char        name[256];      /* Dataset name */
     unsigned    u;              /* Local index variable */
 
     TESTING("istore create");
 
-    dims[0]=TEST_CHUNK_SIZE;
+    dims[0] = my_chunk_dims[0] = 1;
     for (u = 1; u <= H5S_MAX_RANK; u++) {
         /* Initialize the dimension size in this new dimension */
-        dims[u]=TEST_CHUNK_SIZE;
+        dims[u] = my_chunk_dims[u] = 2;
 
         /* Create chunked dataset of this dimensionality */
 	HDsnprintf(name, sizeof name, "%s_%02u", prefix, u);
-	if ((dataset=new_object(f, name, (int)u, dims, chunk_dims)) < 0)
+	if ((dataset=new_object(f, name, (int)u, dims, my_chunk_dims)) < 0)
 	    return FAIL;
 
         /* Close dataset created */
diff --git a/test/tsohm.c b/test/tsohm.c
index abdbe77..0fc94f2 100644
--- a/test/tsohm.c
+++ b/test/tsohm.c
@@ -121,9 +121,9 @@ const int ENUM_VAL[] = {
     20480,  10,
     -1001,    -10
 };
-#define SIZE2_RANK1 10
-#define SIZE2_RANK2 20
-#define SIZE2_DIMS {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}
+#define SIZE2_RANK1 6
+#define SIZE2_RANK2 10
+#define SIZE2_DIMS {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
 
 #define LONG_STRING "00 index.  A long string used for testing. To create new strings, set the first two characters to be some ASCII number other than 00, such as 01."
 
@@ -1376,7 +1376,7 @@ size2_helper(hid_t fcpl_id, int test_file_closing, size2_helper_struct *ret_size
     /* Constants used in this function */
     const int rank1 = SIZE2_RANK1;
     const int rank2 = SIZE2_RANK2;
-    const hsize_t dims[20] = SIZE2_DIMS;
+    const hsize_t dims[SIZE2_RANK2] = SIZE2_DIMS;
     dtype1_struct fill1;
     char fill2[DTYPE2_SIZE];
 
@@ -1745,8 +1745,8 @@ static void size2_verify(void)
     char attr_correct_string[NAME_BUF_SIZE];
     char attr_name[NAME_BUF_SIZE];
     int ndims;
-    hsize_t dims[20];
-    hsize_t correct_dims[20] = SIZE2_DIMS;
+    hsize_t dims[SIZE2_RANK2];
+    hsize_t correct_dims[SIZE2_RANK2] = SIZE2_DIMS;
 
     file_id = H5Fopen(FILENAME, H5F_ACC_RDONLY, H5P_DEFAULT);
     CHECK_I(file_id, "H5Fopen");