Merge pull request #19 in ~VCHOI/my_third_fork from develop to bugfix/HDFFV-10585-investigate-slowness-of-regular

* commit '2456a36f46a15ca44840cb64c7aac213f0ca8bf8': (53 commits)
  Fixed some exit calls.
  Reworked the previously refactorred code.
  Improvement of test code
  Fix CMake build of test needing compression libs
  Fixed error code and error messages Tested on Jelly (very minor)
  Changed H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_COOR to H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_COORD per a review comment.
  Add comment to add tests later to verify conflicting values for MPI-specific properties on multiple opens.
  Updated comments
  Updated based on reviews and refactored test code
  Move ext_path field in H5F_t to H5F_shared_t. Remove unused routine H5F_set_coll_md_read().
  Move coll_md_read and coll_md_write fields in H5F_t to H5F_shared_t.
  Fix namespace usage
  Fix EXISTS test syntax
  Update settings
  Add 32-bit cross-compile toolchain
  Code cleanup and refactor
  Re-ordered items w.r.t. date.
  Whitespace and HD prefix changes
  Fixed typo
  Added notes about HDFFV-10677 and HDFFV-10661
  ...

50 files changed, 2222 insertions, 1357 deletions

diff --git a/src/.indent.pro b/src/.indent.pro
index e0fda85..fa375f0 100644
--- a/src/.indent.pro
+++ b/src/.indent.pro
@@ -68,7 +68,7 @@
 -T H5E_minor_t
 -T H5E_t
 -T H5F_create_t
--T H5F_file_t
+-T H5F_shared_t
 -T H5F_isop_t
 -T H5F_istore_key_t
 -T H5F_istore_ud1_t
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 313d231..97ae847 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -990,7 +990,7 @@ if (LOCAL_BATCH_TEST)
   endif ()
 endif ()
 
-if (NOT EXISTS ${HDF5_GENERATED_SOURCE_DIR}/H5Tinit.c)
+if (NOT EXISTS "${HDF5_GENERATED_SOURCE_DIR}/H5Tinit.c")
   add_executable (H5detect ${HDF5_SRC_DIR}/H5detect.c)
   target_include_directories (H5detect PRIVATE "${HDF5_SRC_DIR};${HDF5_BINARY_DIR};$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:${MPI_C_INCLUDE_DIRS}>")
   target_compile_definitions(H5detect PUBLIC ${HDF_EXTRA_C_FLAGS} ${HDF_EXTRA_FLAGS})
diff --git a/src/H5Cmpio.c b/src/H5Cmpio.c
index 84ec16c..e784487 100644
--- a/src/H5Cmpio.c
+++ b/src/H5Cmpio.c
@@ -222,7 +222,7 @@ H5C_apply_candidate_list(H5F_t * f,
     HDfprintf(stdout, "%s", tbl_buf);
 #endif /* H5C_APPLY_CANDIDATE_LIST__DEBUG */
 
-    if(f->coll_md_write) {
+    if(f->shared->coll_md_write) {
         /* Sanity check */
         HDassert(NULL == cache_ptr->coll_write_list);
 
@@ -386,7 +386,7 @@ H5C_apply_candidate_list(H5F_t * f,
          HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "flush candidates failed")
 
     /* If we've deferred writing to do it collectively, take care of that now */
-    if(f->coll_md_write) {
+    if(f->shared->coll_md_write) {
         /* Sanity check */
         HDassert(cache_ptr->coll_write_list);
 
diff --git a/src/H5D.c b/src/H5D.c
index a8cefd9..96dce3f 100644
--- a/src/H5D.c
+++ b/src/H5D.c
@@ -457,8 +457,8 @@ done:
  *
  *              Failure:    H5I_INVALID_HID
  *
- * Programmer:	Robb Matzke
- *		Tuesday, February  3, 1998
+ * Programmer:  Robb Matzke
+ *              Tuesday, February  3, 1998
  *
  *-------------------------------------------------------------------------
  */
@@ -512,8 +512,8 @@ done:
  *
  *              Failure:    H5I_INVALID_HID
  *
- * Programmer:	Neil Fortner
- *		Wednesday, October 29, 2008
+ * Programmer:  Neil Fortner
+ *              Wednesday, October 29, 2008
  *
  *-------------------------------------------------------------------------
  */
@@ -610,9 +610,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Diterate
+ * Function:    H5Diterate
  *
- * Purpose:	This routine iterates over all the elements selected in a memory
+ * Purpose: This routine iterates over all the elements selected in a memory
  *      buffer.  The callback function is called once for each element selected
  *      in the dataspace.  The selection in the dataspace is modified so
  *      that any elements already iterated over are removed from the selection
@@ -659,11 +659,11 @@ done:
  *              indicating failure. The iterator can be restarted at the next
  *              element.
  *
- * Return:	Returns the return value of the last operator if it was non-zero,
+ * Return:  Returns the return value of the last operator if it was non-zero,
  *          or zero if all elements were processed. Otherwise returns a
  *          negative value.
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Friday, June 11, 1999
  *
  *-------------------------------------------------------------------------
@@ -706,16 +706,16 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Dvlen_reclaim
+ * Function:    H5Dvlen_reclaim
  *
- * Purpose:	Frees the buffers allocated for storing variable-length data
+ * Purpose: Frees the buffers allocated for storing variable-length data
  *      in memory.  Only frees the VL data in the selection defined in the
  *      dataspace.  The dataset transfer property list is required to find the
  *      correct allocation/free methods for the VL data in the buffer.
  *
- * Return:	Non-negative on success, negative on failure
+ * Return:  Non-negative on success, negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Thursday, June 10, 1999
  *
  *-------------------------------------------------------------------------
@@ -756,9 +756,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Dvlen_get_buf_size
+ * Function:    H5Dvlen_get_buf_size
  *
- * Purpose:	This routine checks the number of bytes required to store the VL
+ * Purpose: This routine checks the number of bytes required to store the VL
  *      data from the dataset, using the space_id for the selection in the
  *      dataset on disk and the type_id for the memory representation of the
  *      VL data, in memory.  The *size value is modified according to how many
@@ -772,9 +772,9 @@ done:
  *      Kinda kludgy, but easier than the other method of trying to figure out
  *      the sizes without actually reading the data in... - QAK
  *
- * Return:	Non-negative on success, negative on failure
+ * Return:  Non-negative on success, negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Wednesday, August 11, 1999
  *
  *-------------------------------------------------------------------------
@@ -1095,3 +1095,150 @@ done:
     FUNC_LEAVE_API(ret_value);
 } /* H5Dget_chunk_storage_size() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Dget_num_chunks
+ *
+ * Purpose:     Retrieves the number of chunks that have non-empty intersection
+ *              with a specified selection.
+ *
+ * Note:        Currently, this function only gets the number of all written
+ *              chunks, regardless the dataspace.
+ *
+ * Parameters:
+ *              hid_t dset_id;      IN: Chunked dataset ID
+ *              hid_t fspace_id;    IN: File dataspace ID
+ *              hsize_t *nchunks;   OUT: Number of non-empty chunks
+ *
+ * Return:      Non-negative on success, negative on failure
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              May 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Dget_num_chunks(hid_t dset_id, hid_t fspace_id, hsize_t *nchunks)
+{
+    H5VL_object_t  *vol_obj = NULL;     /* Dataset for this operation */
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "ii*h", dset_id, fspace_id, nchunks);
+
+    /* Check arguments */
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(dset_id, H5I_DATASET)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid dataset identifier")
+    if(NULL == nchunks)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid argument (null)")
+
+    /* Get the number of written chunks */
+    if(H5VL_dataset_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_DATASET_GET_NUM_CHUNKS, fspace_id, nchunks) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "Can't get number of chunks")
+
+done:
+    FUNC_LEAVE_API(ret_value);
+} /* H5Dget_num_chunks() */
+ 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Dget_chunk_info
+ *
+ * Purpose:     Retrieves information about a chunk specified by its index.
+ *
+ * Parameters:
+ *              hid_t dset_id;          IN: Chunked dataset ID
+ *              hid_t fspace_id;        IN: File dataspace ID
+ *              hsize_t index;          IN: Index of written chunk
+ *              hsize_t *offset         OUT: Logical position of the chunk’s
+ *                                           first element in the dataspace
+ *              unsigned *filter_mask   OUT: Mask for identifying the filters in use
+ *              haddr_t *addr           OUT: Address of the chunk
+ *              hsize_t *size           OUT: Size of the chunk
+ *
+ * Return:      Non-negative on success, negative on failure
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              May 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Dget_chunk_info(hid_t dset_id, hid_t fspace_id, hsize_t chk_index, hsize_t *offset, unsigned *filter_mask, haddr_t *addr, hsize_t *size)
+{
+    H5VL_object_t *vol_obj = NULL;     /* Dataset for this operation */
+    hsize_t        nchunks = 0;
+    herr_t         ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE7("e", "iih*h*Iu*a*h", dset_id, fspace_id, chk_index, offset,
+             filter_mask, addr, size);
+
+    /* Check arguments */
+    if(NULL == offset && NULL == filter_mask && NULL == addr && NULL == size)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid arguments, must have at least one non-null output argument")
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(dset_id, H5I_DATASET)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid dataset identifier")
+
+    /* Get the number of written chunks to check range */
+    if(H5VL_dataset_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_DATASET_GET_NUM_CHUNKS, fspace_id, &nchunks) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "Can't get number of chunks")
+
+    /* Check range for chunk index */
+    if(chk_index >= nchunks)
+        HGOTO_ERROR(H5E_DATASET, H5E_BADRANGE, FAIL, "chunk index is out of range")
+
+    /* Call private function to get the chunk info given the chunk's index */
+    if(H5VL_dataset_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_IDX, fspace_id, chk_index, offset, filter_mask, addr, size) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "Can't get chunk info by index")
+
+done:
+    FUNC_LEAVE_API(ret_value);
+} /* H5Dget_chunk_info() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Dget_chunk_info_by_coord
+ *
+ * Purpose:     Retrieves information about a chunk specified by its logical
+ *              coordinates.
+ *
+ * Parameters:
+ *              hid_t dset_id;          IN: Chunked dataset ID
+ *              hsize_t *offset         IN: Logical position of the chunk’s
+ *                                           first element in the dataspace
+ *              unsigned *filter_mask   OUT: Mask for identifying the filters in use
+ *              haddr_t *addr           OUT: Address of the chunk
+ *              hsize_t *size           OUT: Size of the chunk
+ *
+ * Return:      Non-negative on success, negative on failure
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              May 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Dget_chunk_info_by_coord(hid_t dset_id, const hsize_t *offset, unsigned *filter_mask, haddr_t *addr, hsize_t *size)
+{
+    H5VL_object_t  *vol_obj = NULL;     /* Dataset for this operation */
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "i*h*Iu*a*h", dset_id, offset, filter_mask, addr, size);
+
+    /* Check arguments */
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(dset_id, H5I_DATASET)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid dataset identifier")
+    if(NULL == filter_mask && NULL == addr && NULL == size)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid arguments, must have at least one non-null output argument")
+    if(NULL == offset)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid argument (null)")
+
+    /* Call private function to get the chunk info given the chunk's index */
+    if(H5VL_dataset_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_COORD, offset, filter_mask, addr, size) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "Can't get chunk info by its logical coordinates")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Dget_chunk_info_by_coord() */
diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index ec8ea4d..e3bbd59 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -216,6 +216,18 @@ typedef struct H5D_chunk_readvv_ud_t {
     const H5D_t *dset;          /* Dataset to operate on */
 } H5D_chunk_readvv_ud_t;
 
+typedef struct H5D_chunk_info_iter_ud_t {
+    hsize_t  scaled[H5O_LAYOUT_NDIMS];    /* Logical offset of the chunk */
+    hsize_t  ndims;             /* Number of dimensions in the dataset */
+    uint32_t nbytes;            /* Size of stored data in the chunk */
+    unsigned filter_mask;       /* Excluded filters */
+    haddr_t  chunk_addr;        /* Address of the chunk in file */
+    hsize_t  chunk_idx;         /* Chunk index, where the iteration needs to stop */
+    hsize_t  curr_idx;          /* Current index, where the iteration is */
+    unsigned idx_hint;          /* Index of chunk in cache, if present */
+    hbool_t  found;             /* Whether the chunk was found */
+} H5D_chunk_info_iter_ud_t;
+
 /* Callback info for file selection iteration */
 typedef struct H5D_chunk_file_iter_ud_t {
     H5D_chunk_map_t *fm;                /* File->memory chunk mapping info */
@@ -252,6 +264,11 @@ static herr_t H5D__chunk_flush(H5D_t *dset);
 static herr_t H5D__chunk_io_term(const H5D_chunk_map_t *fm);
 static herr_t H5D__chunk_dest(H5D_t *dset);
 
+/* Chunk query operation callbacks */
+static int H5D__get_num_chunks_cb(const H5D_chunk_rec_t *chunk_rec, void *_udata);
+static int H5D__get_chunk_info_cb(const H5D_chunk_rec_t *chunk_rec, void *_udata);
+static int H5D__get_chunk_info_by_coord_cb(const H5D_chunk_rec_t *chunk_rec, void *_udata);
+
 /* "Nonexistent" layout operation callback */
 static ssize_t
 H5D__nonexistent_readvv(const H5D_io_info_t *io_info,
@@ -393,7 +410,6 @@ H5D__chunk_direct_write(const H5D_t *dset, uint32_t filters, hsize_t *offset,
     H5D_chk_idx_info_t idx_info;        /* Chunked index info */
     hsize_t scaled[H5S_MAX_RANK];       /* Scaled coordinates for this chunk */
     hbool_t need_insert = FALSE;        /* Whether the chunk needs to be inserted into the index */
-    H5D_io_info_t io_info;              /* to hold the dset info */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_PACKAGE_TAG(dset->oloc.addr)
@@ -401,13 +417,17 @@ H5D__chunk_direct_write(const H5D_t *dset, uint32_t filters, hsize_t *offset,
     /* Sanity checks */
     HDassert(layout->type == H5D_CHUNKED);
 
-    io_info.dset = dset;
-
     /* Allocate dataspace and initialize it if it hasn't been. */
-    if(!H5D__chunk_is_space_alloc(&layout->storage))
+    if(!H5D__chunk_is_space_alloc(&layout->storage)) {
+        H5D_io_info_t io_info;              /* to hold the dset info */
+
+        io_info.dset = dset;
+        io_info.f_sh = H5F_SHARED(dset->oloc.file);
+
         /* Allocate storage */
         if(H5D__alloc_storage(&io_info, H5D_ALLOC_WRITE, FALSE, NULL) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize storage")
+    } /* end if */
 
     /* Calculate the index of this chunk */
     H5VM_chunk_scaled(dset->shared->ndims, offset, layout->u.chunk.dim, scaled);
@@ -467,7 +487,7 @@ H5D__chunk_direct_write(const H5D_t *dset, uint32_t filters, hsize_t *offset,
     } /* end if */
 
     /* Write the data to the file */
-    if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.chunk_block.offset, data_size, buf) < 0)
+    if(H5F_shared_block_write(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, udata.chunk_block.offset, data_size, buf) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 
     /* Insert the chunk record into the index */
@@ -570,9 +590,9 @@ H5D__chunk_direct_read(const H5D_t *dset, hsize_t *offset, uint32_t* filters,
         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "chunk address isn't defined")
 
     /* Read the chunk data into the supplied buffer */
-    if(H5F_block_read(dset->oloc.file, H5FD_MEM_DRAW, udata.chunk_block.offset, udata.chunk_block.length, buf) < 0)
+    if(H5F_shared_block_read(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, udata.chunk_block.offset, udata.chunk_block.length, buf) < 0)
         HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "unable to read raw data chunk")
-    
+
     /* Return the filter mask */
     *filters = udata.filter_mask;
 
@@ -3332,7 +3352,7 @@ H5D__chunk_flush_entry(const H5D_t *dset, H5D_rdcc_ent_t *ent, hbool_t reset)
         /* Write the data to the file */
         HDassert(H5F_addr_defined(udata.chunk_block.offset));
         H5_CHECK_OVERFLOW(udata.chunk_block.length, hsize_t, size_t);
-        if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.chunk_block.offset, (size_t)udata.chunk_block.length, buf) < 0)
+        if(H5F_shared_block_write(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, udata.chunk_block.offset, (size_t)udata.chunk_block.length, buf) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 
         /* Insert the chunk record into the index */
@@ -3803,7 +3823,7 @@ H5D__chunk_lock(const H5D_io_info_t *io_info, H5D_chunk_ud_t *udata,
                  * size in memory, so allocate memory big enough. */
                 if(NULL == (chunk = H5D__chunk_mem_alloc(my_chunk_alloc, (udata->new_unfilt_chunk ? old_pline : 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, my_chunk_alloc, chunk) < 0)
+                if(H5F_shared_block_read(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, chunk_addr, my_chunk_alloc, chunk) < 0)
                     HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "unable to read raw data chunk")
 
                 if(old_pline && old_pline->nused) {
@@ -4533,7 +4553,7 @@ H5D__chunk_allocate(const H5D_io_info_t *io_info, hbool_t full_overwrite, hsize_
                 } /* end if */
                 else {
 #endif /* H5_HAVE_PARALLEL */
-                    if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, udata.chunk_block.offset, chunk_size, *fill_buf) < 0)
+                    if(H5F_shared_block_write(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, udata.chunk_block.offset, chunk_size, *fill_buf) < 0)
                         HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 #ifdef H5_HAVE_PARALLEL
                 } /* end else */
@@ -4918,7 +4938,7 @@ H5D__chunk_collective_fill(const H5D_t *dset, H5D_chunk_coll_info_t *chunk_info,
         HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set transfer mode")
 
     /* Low-level write (collective) */
-    if(H5F_block_write(dset->oloc.file, H5FD_MEM_DRAW, (haddr_t)0, (blocks) ? (size_t)1 : (size_t)0, fill_buf) < 0)
+    if(H5F_shared_block_write(H5F_SHARED(dset->oloc.file), H5FD_MEM_DRAW, (haddr_t)0, (blocks) ? (size_t)1 : (size_t)0, fill_buf) < 0)
         HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file")
 
     /* Barrier so processes don't race ahead */
@@ -6953,3 +6973,373 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__chunk_format_convert() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_num_chunks_cb
+ *
+ * Purpose:     Callback function that increments the number of written
+ *              chunks in the dataset.
+ *
+ * Note:        Currently, this function only gets the number of all written
+ *              chunks, regardless the dataspace.
+ *
+ * Return:      H5_ITER_CONT
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5D__get_num_chunks_cb(const H5D_chunk_rec_t H5_ATTR_UNUSED *chunk_rec, void *_udata)
+{
+    hsize_t *num_chunks = (hsize_t *)_udata;
+    int ret_value = H5_ITER_CONT;         /* Callback return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    HDassert(num_chunks);
+
+    (*num_chunks)++;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5D__get_num_chunks_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_num_chunks
+ *
+ * Purpose:     Gets the number of written chunks in a dataset.
+ *
+ * Note:        Currently, this function only gets the number of all written
+ *              chunks, regardless the dataspace.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D__get_num_chunks(const H5D_t *dset, const H5S_t H5_ATTR_UNUSED *space, hsize_t *nchunks)
+{
+    H5D_chk_idx_info_t idx_info;                /* Chunked index info */
+    hsize_t            num_chunks = 0;          /* Number of written chunks */
+    H5D_rdcc_ent_t     *ent;                    /* Cache entry  */
+    const H5D_rdcc_t   *rdcc = NULL;            /* Raw data chunk cache */
+    const H5O_layout_t *layout;                 /* Dataset layout */
+    herr_t             ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_PACKAGE_TAG(dset->oloc.addr)
+
+    HDassert(dset);
+    HDassert(dset->shared);
+    HDassert(space);
+    HDassert(nchunks);
+
+    layout = &(dset->shared->layout);    /* Dataset layout */
+    rdcc = &(dset->shared->cache.chunk); /* raw data chunk cache */
+    HDassert(rdcc);
+
+    /* Search for cached chunks that haven't been written out */
+    for(ent = rdcc->head; ent; ent = ent->next)
+        /* Flush the chunk out to disk, to make certain the size is correct later */
+        if(H5D__chunk_flush_entry(dset, ent, FALSE) < 0)
+            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "cannot flush indexed storage buffer")
+
+    /* Compose chunked index info struct */
+    idx_info.f = dset->oloc.file;
+    idx_info.pline = &dset->shared->dcpl_cache.pline;
+    idx_info.layout = &dset->shared->layout.u.chunk;
+    idx_info.storage = &dset->shared->layout.storage.u.chunk;
+
+    /* If the dataset is not written, number of chunks will be 0 */
+    if(!H5F_addr_defined(idx_info.storage->idx_addr)) {
+        *nchunks = 0;
+    }
+    else {
+        /* Iterate over the allocated chunks */
+        if((dset->shared->layout.storage.u.chunk.ops->iterate)(&idx_info, H5D__get_num_chunks_cb, &num_chunks) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve allocated chunk information from index")
+        *nchunks = num_chunks;
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D__get_num_chunks() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_chunk_info_cb
+ *
+ * Purpose:     Get the chunk info of the queried chunk, given by its index.
+ *
+ * Return:      Success:    H5_ITER_CONT or H5_ITER_STOP
+ *                          H5_ITER_STOP indicates the queried chunk is found
+ *              Failure:    Negative (H5_ITER_ERROR)
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5D__get_chunk_info_cb(const H5D_chunk_rec_t *chunk_rec, void *_udata)
+{
+    H5D_chunk_info_iter_ud_t *chunk_info = (H5D_chunk_info_iter_ud_t *)_udata;
+    hsize_t ii = 0;                     /* Dimension index */
+    int     ret_value = H5_ITER_CONT;   /* Callback return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check args */
+    HDassert(chunk_rec);
+    HDassert(chunk_info);
+
+    /* If this is the queried chunk, retrieve its info and stop iterating */
+    if (chunk_info->curr_idx == chunk_info->chunk_idx) {
+        chunk_info->filter_mask = chunk_rec->filter_mask;
+        chunk_info->chunk_addr = chunk_rec->chunk_addr;
+        chunk_info->nbytes = chunk_rec->nbytes;
+        for (ii = 0; ii < chunk_info->ndims; ii++)
+            chunk_info->scaled[ii] = chunk_rec->scaled[ii];
+        chunk_info->found = TRUE;
+
+        /* Stop iterating */
+        ret_value = H5_ITER_STOP;
+    }
+    /* Go to the next chunk */
+    else
+        chunk_info->curr_idx++;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5D__get_chunk_info_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_chunk_info
+ *
+ * Purpose:     Iterate over the chunks in the dataset to get the info
+ *              of the desired chunk.
+ *
+ * Note:        Currently, the domain of the index in this function is of all
+ *              the written chunks, regardless the dataspace.
+ *
+ * Return:      Success: SUCCEED
+ *              Failure: FAIL
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D__get_chunk_info(const H5D_t *dset, const H5S_t H5_ATTR_UNUSED *space, hsize_t chk_index, hsize_t *offset, unsigned *filter_mask, haddr_t *addr, hsize_t *size)
+{
+    H5D_chk_idx_info_t idx_info;           /* Chunked index info */
+    H5D_chunk_info_iter_ud_t udata;        /* User data for callback */
+    const H5D_rdcc_t   *rdcc = NULL;       /* Raw data chunk cache */
+    H5D_rdcc_ent_t     *ent;               /* Cache entry index */
+    hsize_t            ii = 0;             /* Dimension index */
+    herr_t             ret_value = SUCCEED;/* Return value */
+
+    FUNC_ENTER_PACKAGE_TAG(dset->oloc.addr)
+
+    HDassert(dset);
+    HDassert(dset->shared);
+    HDassert(space);
+
+    /* Get the raw data chunk cache */
+    rdcc = &(dset->shared->cache.chunk);
+    HDassert(rdcc);
+
+    /* Search for cached chunks that haven't been written out */
+    for(ent = rdcc->head; ent; ent = ent->next)
+        /* Flush the chunk out to disk, to make certain the size is correct later */
+        if(H5D__chunk_flush_entry(dset, ent, FALSE) < 0)
+            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "cannot flush indexed storage buffer")
+
+    /* Compose chunked index info struct */
+    idx_info.f = dset->oloc.file;
+    idx_info.pline = &dset->shared->dcpl_cache.pline;
+    idx_info.layout = &dset->shared->layout.u.chunk;
+    idx_info.storage = &dset->shared->layout.storage.u.chunk;
+
+    /* Set addr & size for when dset is not written or queried chunk is not found */
+    if (addr)
+        *addr = HADDR_UNDEF;
+    if (size)
+        *size = 0;
+
+    /* If the chunk is written, get its info, otherwise, return without error */
+    if(H5F_addr_defined(idx_info.storage->idx_addr)) {
+        /* Initialize before iteration */
+        udata.chunk_idx = chk_index;
+        udata.curr_idx = 0;
+        udata.ndims = dset->shared->ndims;
+        udata.nbytes = 0;
+        udata.filter_mask = 0;
+        udata.chunk_addr = HADDR_UNDEF;
+        udata.found = FALSE;
+
+        /* Iterate over the allocated chunks */
+        if((dset->shared->layout.storage.u.chunk.ops->iterate)(&idx_info, H5D__get_chunk_info_cb, &udata) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve allocated chunk information from index")
+
+        /* Obtain requested info if the chunk is found */
+        if(udata.found) {
+            if(filter_mask)
+                *filter_mask = udata.filter_mask;
+            if(addr)
+                *addr = udata.chunk_addr;
+            if(size)
+                *size = udata.nbytes;
+            if(offset)
+                for(ii = 0; ii < udata.ndims; ii++)
+                    offset[ii] = udata.scaled[ii] * dset->shared->layout.u.chunk.dim[ii];
+        }
+    } /* end if H5F_addr_defined */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D__get_chunk_info() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_chunk_info_by_coord_cb
+ *
+ * Purpose:     Get the chunk info of the desired chunk, given its offset
+ *              coordinates.
+ *
+ * Return:      Success:    H5_ITER_CONT or H5_ITER_STOP
+ *              Failure:    Negative (H5_ITER_ERROR)
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5D__get_chunk_info_by_coord_cb(const H5D_chunk_rec_t *chunk_rec, void *_udata)
+{
+    hsize_t ii;
+    H5D_chunk_info_iter_ud_t *chunk_info = (H5D_chunk_info_iter_ud_t *)_udata;
+    hbool_t different = FALSE;      /* TRUE when a scaled value pair mismatch */
+    int ret_value = H5_ITER_CONT;   /* Callback return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check args */
+    HDassert(chunk_rec);
+    HDassert(chunk_info);
+
+    /* Going through the scaled, stop when a mismatch is found */
+    for (ii = 0; ii < chunk_info->ndims && !different; ii++)
+        if (chunk_info->scaled[ii] != chunk_rec->scaled[ii])
+            different = TRUE;
+
+    /* Same scaled coords means the chunk is found, copy the chunk info */
+    if (!different) {
+        chunk_info->nbytes = chunk_rec->nbytes;
+        chunk_info->filter_mask = chunk_rec->filter_mask;
+        chunk_info->chunk_addr = chunk_rec->chunk_addr;
+        chunk_info->found = TRUE;
+
+        /* Stop iterating */
+        ret_value = H5_ITER_STOP;
+    }
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5D__get_chunk_info_by_coord_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__get_chunk_info_by_coord
+ *
+ * Purpose:     Iterate over the chunks in the dataset to get the info
+ *              of the desired chunk, given by its offset coordinates.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ * Programmer:  Binh-Minh Ribler
+ *              June 2019 (HDFFV-10677)
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D__get_chunk_info_by_coord(const H5D_t *dset, const hsize_t *offset, unsigned* filter_mask, haddr_t *addr, hsize_t *size)
+{
+    const H5O_layout_t *layout = NULL;  /* Dataset layout */
+    const H5D_rdcc_t   *rdcc = NULL;    /* Raw data chunk cache */
+    H5D_rdcc_ent_t     *ent;            /* Cache entry index */
+    H5D_chk_idx_info_t  idx_info;       /* Chunked index info */
+    H5D_chunk_info_iter_ud_t udata;     /* User data for callback */
+    herr_t              ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_PACKAGE_TAG(dset->oloc.addr)
+
+    /* Check args */
+    HDassert(dset);
+    HDassert(dset->shared);
+    HDassert(offset);
+
+    /* Get dataset layout and raw data chunk cache */
+    layout = &(dset->shared->layout);
+    rdcc = &(dset->shared->cache.chunk);
+    HDassert(layout);
+    HDassert(rdcc);
+    HDassert(H5D_CHUNKED == layout->type);
+
+    /* Search for cached chunks that haven't been written out */
+    for(ent = rdcc->head; ent; ent = ent->next)
+        /* Flush the chunk out to disk, to make certain the size is correct later */
+        if(H5D__chunk_flush_entry(dset, ent, FALSE) < 0)
+            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "cannot flush indexed storage buffer")
+
+    /* Set addr & size for when dset is not written or queried chunk is not found */
+    if (addr)
+        *addr = HADDR_UNDEF;
+    if (size)
+        *size = 0;
+
+    /* Compose chunked index info struct */
+    idx_info.f = dset->oloc.file;
+    idx_info.pline = &dset->shared->dcpl_cache.pline;
+    idx_info.layout = &dset->shared->layout.u.chunk;
+    idx_info.storage = &dset->shared->layout.storage.u.chunk;
+
+    /* If the dataset is not written, return without errors */
+    if(H5F_addr_defined(idx_info.storage->idx_addr)) {
+        /* Calculate the scaled of this chunk */
+        H5VM_chunk_scaled(dset->shared->ndims, offset, layout->u.chunk.dim, udata.scaled);
+        udata.scaled[dset->shared->ndims] = 0;
+
+        /* Initialize before iteration */
+        udata.ndims = dset->shared->ndims;
+        udata.nbytes = 0;
+        udata.filter_mask = 0;
+        udata.chunk_addr = HADDR_UNDEF;
+        udata.found = FALSE;
+
+        /* Iterate over the allocated chunks to find the requested chunk */
+        if((dset->shared->layout.storage.u.chunk.ops->iterate)(&idx_info, H5D__get_chunk_info_by_coord_cb, &udata) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve information of the chunk by its scaled coordinates")
+
+        /* Obtain requested info if the chunk is found */
+        if (udata.found) {
+            if(filter_mask)
+                *filter_mask = udata.filter_mask;
+            if(addr)
+                *addr = udata.chunk_addr;
+            if(size)
+                *size = udata.nbytes;
+        }
+    } /* end if H5F_addr_defined */
+
+done:
+    FUNC_LEAVE_NOAPI_TAG(ret_value)
+} /* end H5D__get_chunk_info_by_coord() */
+
diff --git a/src/H5Dcontig.c b/src/H5Dcontig.c
index 8733633..c9f9fc2 100644
--- a/src/H5Dcontig.c
+++ b/src/H5Dcontig.c
@@ -58,7 +58,7 @@
 
 /* Callback info for sieve buffer readvv operation */
 typedef struct H5D_contig_readvv_sieve_ud_t {
-    H5F_t *file;                /* File for dataset */
+    H5F_shared_t *f_sh;         /* Shared file for dataset */
     H5D_rdcdc_t *dset_contig;   /* Cached information about contiguous data */
     const H5D_contig_storage_t *store_contig;    /* Contiguous storage info for this I/O operation */
     unsigned char *rbuf;        /* Pointer to buffer to fill */
@@ -66,14 +66,14 @@ typedef struct H5D_contig_readvv_sieve_ud_t {
 
 /* Callback info for [plain] readvv operation */
 typedef struct H5D_contig_readvv_ud_t {
-    H5F_t *file;                /* File for dataset */
+    H5F_shared_t *f_sh;         /* Shared file for dataset */
     haddr_t dset_addr;          /* Address of dataset */
     unsigned char *rbuf;        /* Pointer to buffer to fill */
 } H5D_contig_readvv_ud_t;
 
 /* Callback info for sieve buffer writevv operation */
 typedef struct H5D_contig_writevv_sieve_ud_t {
-    H5F_t *file;                /* File for dataset */
+    H5F_shared_t *f_sh;         /* Shared file for dataset */
     H5D_rdcdc_t *dset_contig;   /* Cached information about contiguous data */
     const H5D_contig_storage_t *store_contig;    /* Contiguous storage info for this I/O operation */
     const unsigned char *wbuf;  /* Pointer to buffer to write */
@@ -81,7 +81,7 @@ typedef struct H5D_contig_writevv_sieve_ud_t {
 
 /* Callback info for [plain] writevv operation */
 typedef struct H5D_contig_writevv_ud_t {
-    H5F_t *file;                /* File for dataset */
+    H5F_shared_t *f_sh;         /* Shared file for dataset */
     haddr_t dset_addr;          /* Address of dataset */
     const unsigned char *wbuf;  /* Pointer to buffer to write */
 } H5D_contig_writevv_ud_t;
@@ -718,7 +718,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
     void *_udata)
 {
     H5D_contig_readvv_sieve_ud_t *udata = (H5D_contig_readvv_sieve_ud_t *)_udata; /* User data for H5VM_opvv() operator */
-    H5F_t *file = udata->file;        /* File for dataset */
+    H5F_shared_t *f_sh = udata->f_sh;   /* Shared file for dataset */
     H5D_rdcdc_t *dset_contig = udata->dset_contig; /* Cached information about contiguous data */
     const H5D_contig_storage_t *store_contig = udata->store_contig;    /* Contiguous storage info for this I/O operation */
     unsigned char *buf;         /* Pointer to buffer to fill */
@@ -750,7 +750,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
     if(NULL == dset_contig->sieve_buf) {
         /* Check if we can actually hold the I/O request in the sieve buffer */
         if(len > dset_contig->sieve_buf_size) {
-            if(H5F_block_read(file, H5FD_MEM_DRAW, addr, len, buf) < 0)
+            if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, addr, len, buf) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
         } /* end if */
         else {
@@ -762,7 +762,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
             dset_contig->sieve_loc = addr;
 
             /* Make certain we don't read off the end of the file */
-            if(HADDR_UNDEF == (rel_eoa = H5F_get_eoa(file, H5FD_MEM_DRAW)))
+            if(HADDR_UNDEF == (rel_eoa = H5F_shared_get_eoa(f_sh, H5FD_MEM_DRAW)))
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to determine file size")
 
             /* Set up the buffer parameters */
@@ -773,7 +773,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
             H5_CHECKED_ASSIGN(dset_contig->sieve_size, size_t, min, hsize_t);
 
             /* Read the new sieve buffer */
-            if(H5F_block_read(file, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
+            if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
 
             /* Grab the data out of the buffer (must be first piece of data in buffer ) */
@@ -804,7 +804,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                     /* Flush the sieve buffer, if it's dirty */
                     if(dset_contig->sieve_dirty) {
                         /* Write to file */
-                        if(H5F_block_write(file, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
+                        if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
                             HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
                         /* Reset sieve buffer dirty flag */
@@ -813,7 +813,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                 } /* end if */
 
                 /* Read directly into the user's buffer */
-                if(H5F_block_read(file, H5FD_MEM_DRAW, addr, len, buf) < 0)
+                if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, addr, len, buf) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
             } /* end if */
             /* Element size fits within the buffer size */
@@ -821,7 +821,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                 /* Flush the sieve buffer if it's dirty */
                 if(dset_contig->sieve_dirty) {
                     /* Write to file */
-                    if(H5F_block_write(file, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
+                    if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
                         HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
                     /* Reset sieve buffer dirty flag */
@@ -832,7 +832,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                 dset_contig->sieve_loc = addr;
 
                 /* Make certain we don't read off the end of the file */
-                if(HADDR_UNDEF == (rel_eoa = H5F_get_eoa(file, H5FD_MEM_DRAW)))
+                if(HADDR_UNDEF == (rel_eoa = H5F_shared_get_eoa(f_sh, H5FD_MEM_DRAW)))
                     HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to determine file size")
 
                 /* Only need this when resizing sieve buffer */
@@ -847,7 +847,7 @@ H5D__contig_readvv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                 H5_CHECKED_ASSIGN(dset_contig->sieve_size, size_t, min, hsize_t);
 
                 /* Read the new sieve buffer */
-                if(H5F_block_read(file, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
+                if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
 
                 /* Grab the data out of the buffer (must be first piece of data in buffer ) */
@@ -885,7 +885,7 @@ H5D__contig_readvv_cb(hsize_t dst_off, hsize_t src_off, size_t len, void *_udata
     FUNC_ENTER_STATIC
 
     /* Write data */
-    if(H5F_block_read(udata->file, H5FD_MEM_DRAW, (udata->dset_addr + dst_off),
+    if(H5F_shared_block_read(udata->f_sh, H5FD_MEM_DRAW, (udata->dset_addr + dst_off),
             len, (udata->rbuf + src_off)) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
@@ -931,11 +931,11 @@ H5D__contig_readvv(const H5D_io_info_t *io_info,
     HDassert(mem_off_arr);
 
     /* Check if data sieving is enabled */
-    if(H5F_HAS_FEATURE(io_info->dset->oloc.file, H5FD_FEAT_DATA_SIEVE)) {
+    if(H5F_SHARED_HAS_FEATURE(io_info->f_sh, H5FD_FEAT_DATA_SIEVE)) {
         H5D_contig_readvv_sieve_ud_t udata;     /* User data for H5VM_opvv() operator */
 
         /* Set up user data for H5VM_opvv() */
-        udata.file = io_info->dset->oloc.file;
+        udata.f_sh = io_info->f_sh;
         udata.dset_contig = &(io_info->dset->shared->cache.contig);
         udata.store_contig = &(io_info->store->contig);
         udata.rbuf = (unsigned char *)io_info->u.rbuf;
@@ -950,7 +950,7 @@ H5D__contig_readvv(const H5D_io_info_t *io_info,
         H5D_contig_readvv_ud_t udata;     /* User data for H5VM_opvv() operator */
 
         /* Set up user data for H5VM_opvv() */
-        udata.file = io_info->dset->oloc.file;
+        udata.f_sh = io_info->f_sh;
         udata.dset_addr = io_info->store->contig.dset_addr;
         udata.rbuf = (unsigned char *)io_info->u.rbuf;
 
@@ -983,7 +983,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
     void *_udata)
 {
     H5D_contig_writevv_sieve_ud_t *udata = (H5D_contig_writevv_sieve_ud_t *)_udata; /* User data for H5VM_opvv() operator */
-    H5F_t *file = udata->file;        /* File for dataset */
+    H5F_shared_t *f_sh = udata->f_sh;   /* Shared file for dataset */
     H5D_rdcdc_t *dset_contig = udata->dset_contig; /* Cached information about contiguous data */
     const H5D_contig_storage_t *store_contig = udata->store_contig;    /* Contiguous storage info for this I/O operation */
     const unsigned char *buf;   /* Pointer to buffer to fill */
@@ -1015,7 +1015,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
     if(NULL == dset_contig->sieve_buf) {
         /* Check if we can actually hold the I/O request in the sieve buffer */
         if(len > dset_contig->sieve_buf_size) {
-            if(H5F_block_write(file, H5FD_MEM_DRAW, addr, len, buf) < 0)
+            if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, addr, len, buf) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
         } /* end if */
         else {
@@ -1031,7 +1031,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
             dset_contig->sieve_loc = addr;
 
             /* Make certain we don't read off the end of the file */
-            if(HADDR_UNDEF == (rel_eoa = H5F_get_eoa(file, H5FD_MEM_DRAW)))
+            if(HADDR_UNDEF == (rel_eoa = H5F_shared_get_eoa(f_sh, H5FD_MEM_DRAW)))
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to determine file size")
 
             /* Set up the buffer parameters */
@@ -1044,7 +1044,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
             /* Check if there is any point in reading the data from the file */
             if(dset_contig->sieve_size > len) {
                 /* Read the new sieve buffer */
-                if(H5F_block_read(file, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
+                if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
             } /* end if */
 
@@ -1084,7 +1084,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                     /* Flush the sieve buffer, if it's dirty */
                     if(dset_contig->sieve_dirty) {
                         /* Write to file */
-                        if(H5F_block_write(file, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
+                        if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
                             HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
                         /* Reset sieve buffer dirty flag */
@@ -1097,7 +1097,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                 } /* end if */
 
                 /* Write directly from the user's buffer */
-                if(H5F_block_write(file, H5FD_MEM_DRAW, addr, len, buf) < 0)
+                if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, addr, len, buf) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
             } /* end if */
             /* Element size fits within the buffer size */
@@ -1132,7 +1132,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                     /* Flush the sieve buffer if it's dirty */
                     if(dset_contig->sieve_dirty) {
                         /* Write to file */
-                        if(H5F_block_write(file, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
+                        if(H5F_shared_block_write(f_sh, H5FD_MEM_DRAW, sieve_start, sieve_size, dset_contig->sieve_buf) < 0)
                             HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
                         /* Reset sieve buffer dirty flag */
@@ -1143,7 +1143,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                     dset_contig->sieve_loc = addr;
 
                     /* Make certain we don't read off the end of the file */
-                    if(HADDR_UNDEF == (rel_eoa = H5F_get_eoa(file, H5FD_MEM_DRAW)))
+                    if(HADDR_UNDEF == (rel_eoa = H5F_shared_get_eoa(f_sh, H5FD_MEM_DRAW)))
                         HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to determine file size")
 
                     /* Only need this when resizing sieve buffer */
@@ -1160,7 +1160,7 @@ H5D__contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
                     /* Check if there is any point in reading the data from the file */
                     if(dset_contig->sieve_size > len) {
                         /* Read the new sieve buffer */
-                        if(H5F_block_read(file, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
+                        if(H5F_shared_block_read(f_sh, H5FD_MEM_DRAW, dset_contig->sieve_loc, dset_contig->sieve_size, dset_contig->sieve_buf) < 0)
                             HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "block read failed")
                     } /* end if */
 
@@ -1200,7 +1200,7 @@ H5D__contig_writevv_cb(hsize_t dst_off, hsize_t src_off, size_t len, void *_udat
     FUNC_ENTER_STATIC
 
     /* Write data */
-    if(H5F_block_write(udata->file, H5FD_MEM_DRAW, (udata->dset_addr + dst_off), len, (udata->wbuf + src_off)) < 0)
+    if(H5F_shared_block_write(udata->f_sh, H5FD_MEM_DRAW, (udata->dset_addr + dst_off), len, (udata->wbuf + src_off)) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "block write failed")
 
 done:
@@ -1245,11 +1245,11 @@ H5D__contig_writevv(const H5D_io_info_t *io_info,
     HDassert(mem_off_arr);
 
     /* Check if data sieving is enabled */
-    if(H5F_HAS_FEATURE(io_info->dset->oloc.file, H5FD_FEAT_DATA_SIEVE)) {
+    if(H5F_SHARED_HAS_FEATURE(io_info->f_sh, H5FD_FEAT_DATA_SIEVE)) {
         H5D_contig_writevv_sieve_ud_t udata;    /* User data for H5VM_opvv() operator */
 
         /* Set up user data for H5VM_opvv() */
-        udata.file = io_info->dset->oloc.file;
+        udata.f_sh = io_info->f_sh;
         udata.dset_contig = &(io_info->dset->shared->cache.contig);
         udata.store_contig = &(io_info->store->contig);
         udata.wbuf = (const unsigned char *)io_info->u.wbuf;
@@ -1264,7 +1264,7 @@ H5D__contig_writevv(const H5D_io_info_t *io_info,
         H5D_contig_writevv_ud_t udata;     /* User data for H5VM_opvv() operator */
 
         /* Set up user data for H5VM_opvv() */
-        udata.file = io_info->dset->oloc.file;
+        udata.f_sh = io_info->f_sh;
         udata.dset_addr = io_info->store->contig.dset_addr;
         udata.wbuf = (const unsigned char *)io_info->u.wbuf;
 
diff --git a/src/H5Dint.c b/src/H5Dint.c
index 1e9c6ff..ada542e 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -2932,7 +2932,7 @@ H5D__flush_sieve_buf(H5D_t *dataset)
         HDassert(dataset->shared->layout.type != H5D_COMPACT);      /* We should never have a sieve buffer for compact storage */
 
         /* Write dirty data sieve buffer to file */
-        if(H5F_block_write(dataset->oloc.file, H5FD_MEM_DRAW, dataset->shared->cache.contig.sieve_loc,
+        if(H5F_shared_block_write(H5F_SHARED(dataset->oloc.file), H5FD_MEM_DRAW, dataset->shared->cache.contig.sieve_loc,
                 dataset->shared->cache.contig.sieve_size, dataset->shared->cache.contig.sieve_buf) < 0)
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed")
 
diff --git a/src/H5Dio.c b/src/H5Dio.c
index cdb73e3..1e6e70d 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -857,6 +857,7 @@ H5D__ioinfo_init(H5D_t *dset, const H5D_type_info_t *type_info,
 
     /* Set up "normal" I/O fields */
     io_info->dset = dset;
+    io_info->f_sh = H5F_SHARED(dset->oloc.file);
     io_info->store = store;
 
     /* Set I/O operations to initial values */
diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index 467b1b7..0dbbe9f 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -457,7 +457,7 @@ H5D__mpio_select_read(const H5D_io_info_t *io_info, const H5D_type_info_t H5_ATT
     FUNC_ENTER_PACKAGE
 
     H5_CHECK_OVERFLOW(mpi_buf_count, hsize_t, size_t);
-    if(H5F_block_read(io_info->dset->oloc.file, H5FD_MEM_DRAW, store_contig->dset_addr, (size_t)mpi_buf_count, io_info->u.rbuf) < 0)
+    if(H5F_shared_block_read(io_info->f_sh, H5FD_MEM_DRAW, store_contig->dset_addr, (size_t)mpi_buf_count, io_info->u.rbuf) < 0)
         HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "can't finish collective parallel read")
 
 done:
@@ -487,7 +487,7 @@ H5D__mpio_select_write(const H5D_io_info_t *io_info, const H5D_type_info_t H5_AT
 
     /*OKAY: CAST DISCARDS CONST QUALIFIER*/
     H5_CHECK_OVERFLOW(mpi_buf_count, hsize_t, size_t);
-    if(H5F_block_write(io_info->dset->oloc.file, H5FD_MEM_DRAW, store_contig->dset_addr, (size_t)mpi_buf_count, io_info->u.wbuf) < 0)
+    if(H5F_shared_block_write(io_info->f_sh, H5FD_MEM_DRAW, store_contig->dset_addr, (size_t)mpi_buf_count, io_info->u.wbuf) < 0)
        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "can't finish collective parallel write")
 
 done:
@@ -3153,7 +3153,7 @@ H5D__filtered_collective_chunk_entry_io(H5D_filtered_collective_io_info_t *chunk
         if(H5CX_set_io_xfer_mode(H5FD_MPIO_INDEPENDENT) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set MPI-I/O transfer mode")
 
-        if(H5F_block_read(io_info->dset->oloc.file, H5FD_MEM_DRAW, chunk_entry->chunk_states.chunk_current.offset,
+        if(H5F_shared_block_read(io_info->f_sh, H5FD_MEM_DRAW, chunk_entry->chunk_states.chunk_current.offset,
                 chunk_entry->chunk_states.new_chunk.length, chunk_entry->buf) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to read raw data chunk")
 
diff --git a/src/H5Dnone.c b/src/H5Dnone.c
index be421b6..9346220 100644
--- a/src/H5Dnone.c
+++ b/src/H5Dnone.c
@@ -242,9 +242,9 @@ H5D__none_idx_iterate(const H5D_chk_idx_info_t *idx_info,
     unsigned u;		/* Local index variable */
     int curr_dim;       /* Current rank */
     hsize_t idx;    	/* Array index of chunk */
-    int ret_value = -1; /* Return value */
+    int ret_value = H5_ITER_CONT; /* Return value */
 
-    FUNC_ENTER_STATIC_NOERR
+    FUNC_ENTER_STATIC
 
     /* Sanity checks */
     HDassert(idx_info);
@@ -266,34 +266,35 @@ H5D__none_idx_iterate(const H5D_chk_idx_info_t *idx_info,
     HDassert(ndims > 0);
 
     /* Iterate over all the chunks in the dataset's dataspace */
-    for(u = 0; u < idx_info->layout->nchunks; u++) {
-	/* Calculate the index of this chunk */
-	idx = H5VM_array_offset_pre(ndims, idx_info->layout->max_down_chunks, chunk_rec.scaled);
-
-	/* Calculate the address of the chunk */
-	chunk_rec.chunk_addr = idx_info->storage->idx_addr + idx * idx_info->layout->size;
-
-	/* Make "generic chunk" callback */
-	if((ret_value = (*chunk_cb)(&chunk_rec, chunk_udata)) < 0)
-	    HERROR(H5E_DATASET, H5E_CALLBACK, "failure in generic chunk iterator callback");
-
-	/* Update coordinates of chunk in dataset */
-	curr_dim = (int)(ndims - 1);
-	while(curr_dim >= 0) {
-	    /* Increment coordinate in current dimension */
-	    chunk_rec.scaled[curr_dim]++;
-
-	    /* Check if we went off the end of the current dimension */
-	    if(chunk_rec.scaled[curr_dim] >= idx_info->layout->chunks[curr_dim]) {
-		/* Reset coordinate & move to next faster dimension */
-		chunk_rec.scaled[curr_dim] = 0;
-		curr_dim--;
-	    } /* end if */
-	    else
-		break;
-	} /* end while */
+    for(u = 0; u < idx_info->layout->nchunks && ret_value == H5_ITER_CONT; u++) {
+	    /* Calculate the index of this chunk */
+	    idx = H5VM_array_offset_pre(ndims, idx_info->layout->max_down_chunks, chunk_rec.scaled);
+
+	    /* Calculate the address of the chunk */
+	    chunk_rec.chunk_addr = idx_info->storage->idx_addr + idx * idx_info->layout->size;
+
+	    /* Make "generic chunk" callback */
+	    if((ret_value = (*chunk_cb)(&chunk_rec, chunk_udata)) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CALLBACK, H5_ITER_ERROR, "failure in generic chunk iterator callback")
+
+	    /* Update coordinates of chunk in dataset */
+	    curr_dim = (int)(ndims - 1);
+	    while(curr_dim >= 0) {
+	        /* Increment coordinate in current dimension */
+	        chunk_rec.scaled[curr_dim]++;
+
+	        /* Check if we went off the end of the current dimension */
+	        if(chunk_rec.scaled[curr_dim] >= idx_info->layout->chunks[curr_dim]) {
+		        /* Reset coordinate & move to next faster dimension */
+		        chunk_rec.scaled[curr_dim] = 0;
+		        curr_dim--;
+	        } /* end if */
+	        else
+		        break;
+	    } /* end while */
     } /* end for */
 
+done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__none_idx_iterate() */
 
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 638c8a5..723acf9 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -47,11 +47,13 @@
 /* [Simple] Macro to construct a H5D_io_info_t from it's components */
 #define H5D_BUILD_IO_INFO_WRT(io_info, ds, str, buf)                    \
     (io_info)->dset = ds;                                               \
+    (io_info)->f_sh = H5F_SHARED((ds)->oloc.file);                      \
     (io_info)->store = str;                                             \
     (io_info)->op_type = H5D_IO_OP_WRITE;                               \
     (io_info)->u.wbuf = buf
 #define H5D_BUILD_IO_INFO_RD(io_info, ds, str, buf)                     \
     (io_info)->dset = ds;                                               \
+    (io_info)->f_sh = H5F_SHARED((ds)->oloc.file);                      \
     (io_info)->store = str;                                             \
     (io_info)->op_type = H5D_IO_OP_READ;                                \
     (io_info)->u.rbuf = buf
@@ -207,6 +209,8 @@ typedef enum H5D_io_op_type_t {
 
 typedef struct H5D_io_info_t {
     const H5D_t *dset;          /* Pointer to dataset being operated on */
+/* QAK: Delete the f_sh field when oloc has a shared file pointer? */
+    H5F_shared_t *f_sh;         /* Pointer to shared file struct that dataset is within */
 #ifdef H5_HAVE_PARALLEL
     MPI_Comm comm;              /* MPI communicator for file */
     hbool_t using_mpi_vfd;      /* Whether the file is using an MPI-based VFD */
@@ -565,6 +569,9 @@ H5_DLL herr_t H5D__get_space_status(const H5D_t *dset, H5D_space_status_t *alloc
 H5_DLL herr_t H5D__alloc_storage(const H5D_io_info_t *io_info, H5D_time_alloc_t time_alloc, hbool_t full_overwrite, hsize_t old_dim[]);
 H5_DLL herr_t H5D__get_storage_size(const H5D_t *dset, hsize_t *storage_size);
 H5_DLL herr_t H5D__get_chunk_storage_size(H5D_t *dset, const hsize_t *offset, hsize_t *storage_size);
+H5_DLL herr_t H5D__get_num_chunks(const H5D_t *dset, const H5S_t *space, hsize_t *nchunks);
+H5_DLL herr_t H5D__get_chunk_info(const H5D_t *dset, const H5S_t *space, hsize_t chk_idx, hsize_t *coord, unsigned *filter_mask, haddr_t *offset, hsize_t *size);
+H5_DLL herr_t H5D__get_chunk_info_by_coord(const H5D_t *dset, const hsize_t *coord, unsigned *filter_mask, haddr_t *addr, hsize_t *size);
 H5_DLL haddr_t H5D__get_offset(const H5D_t *dset);
 H5_DLL void *H5D__vlen_get_buf_size_alloc(size_t size, void *info);
 H5_DLL herr_t H5D__vlen_get_buf_size(void *elem, hid_t type_id, unsigned ndim, const hsize_t *point, void *op_data);
diff --git a/src/H5Dpublic.h b/src/H5Dpublic.h
index 63f1a24..7234d16 100644
--- a/src/H5Dpublic.h
+++ b/src/H5Dpublic.h
@@ -142,6 +142,9 @@ H5_DLL hid_t H5Dget_create_plist(hid_t dset_id);
 H5_DLL hid_t H5Dget_access_plist(hid_t dset_id);
 H5_DLL hsize_t H5Dget_storage_size(hid_t dset_id);
 H5_DLL herr_t H5Dget_chunk_storage_size(hid_t dset_id, const hsize_t *offset, hsize_t *chunk_bytes);
+H5_DLL herr_t H5Dget_num_chunks(hid_t dset_id, hid_t fspace_id, hsize_t *nchunks);
+H5_DLL herr_t H5Dget_chunk_info_by_coord(hid_t dset_id, const hsize_t *coord, unsigned *filter_mask, haddr_t *addr, hsize_t *size);
+H5_DLL herr_t H5Dget_chunk_info(hid_t dset_id, hid_t fspace_id, hsize_t chk_idx, hsize_t *coord, unsigned *filter_mask, haddr_t *addr, hsize_t *size);
 H5_DLL haddr_t H5Dget_offset(hid_t dset_id);
 H5_DLL herr_t H5Dread(hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id,
 			hid_t file_space_id, hid_t plist_id, void *buf/*out*/);
diff --git a/src/H5EA.c b/src/H5EA.c
index d0bf474..96eee12 100644
--- a/src/H5EA.c
+++ b/src/H5EA.c
@@ -987,19 +987,25 @@ END_FUNC(PRIV)  /* end H5EA_delete() */
  * Purpose:	Iterate over the elements of an extensible array
  *		(copied and modified from FA_iterate() in H5FA.c)
  *
- * Return:      SUCCEED/FAIL
+ * Return:      H5_ITER_CONT/H5_ITER_ERROR
  *
  * Programmer:  Vailin Choi; Feb 2015
  *
+ * Modification:
+ *              Prototype changed (HDFFV-10661)
+ *              - herr_t to int
+ *              - SUCCEED/FAIL to H5_ITER_CONT/H5_ITER_ERROR
+ *              June 6, 2019 -BMR
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(PRIV, ERR,
-herr_t, SUCCEED, FAIL,
+int, H5_ITER_CONT, H5_ITER_ERROR,
 H5EA_iterate(H5EA_t *ea, H5EA_operator_t op, void *udata))
 
     /* Local variables */
     uint8_t     *elmt = NULL;
     hsize_t     u;
+    int         cb_ret = H5_ITER_CONT;     /* Return value from callback */
 
     /*
      * Check arguments.
@@ -1013,9 +1019,7 @@ H5EA_iterate(H5EA_t *ea, H5EA_operator_t op, void *udata))
         H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array element")
 
     /* Iterate over all elements in array */
-    for(u = 0; u < ea->hdr->stats.stored.max_idx_set; u++) {
-        int cb_ret;     /* Return value from callback */
-
+    for(u = 0; u < ea->hdr->stats.stored.max_idx_set && cb_ret == H5_ITER_CONT; u++) {
         /* Get array element */
         if(H5EA_get(ea, u, elmt) < 0)
             H5E_THROW(H5E_CANTGET, "unable to delete fixed array")
diff --git a/src/H5FA.c b/src/H5FA.c
index 8c86193..df53f27 100644
--- a/src/H5FA.c
+++ b/src/H5FA.c
@@ -686,20 +686,26 @@ END_FUNC(PRIV)  /* end H5FA_delete() */
  * Note:        This is not very efficient, we should be iterating directly
  *              over the fixed array's direct block [pages].
  *
- * Return:      SUCCEED/FAIL
+ * Return:      H5_ITER_CONT/H5_ITER_ERROR
  *
  * Programmer:  Vailin Choi
  *              Thursday, April 30, 2009
  *
+ * Modification:
+ *              Prototype changed (HDFFV-10661)
+ *              - herr_t to int
+ *              - SUCCEED/FAIL to H5_ITER_CONT/H5_ITER_ERROR
+ *              June 6, 2019 -BMR
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(PRIV, ERR,
-herr_t, SUCCEED, FAIL,
+int, H5_ITER_CONT, H5_ITER_ERROR,
 H5FA_iterate(H5FA_t *fa, H5FA_operator_t op, void *udata))
 
     /* Local variables */
     uint8_t     *elmt = NULL;
     hsize_t     u;
+    int         cb_ret = H5_ITER_CONT;     /* Return value from callback */
 
     /*
      * Check arguments.
@@ -713,9 +719,7 @@ H5FA_iterate(H5FA_t *fa, H5FA_operator_t op, void *udata))
         H5E_THROW(H5E_CANTALLOC, "memory allocation failed for fixed array element")
 
     /* Iterate over all elements in array */
-    for(u = 0; u < fa->hdr->stats.nelmts; u++) {
-        int cb_ret;     /* Return value from callback */
-
+    for(u = 0; u < fa->hdr->stats.nelmts && cb_ret == H5_ITER_CONT; u++) {
         /* Get array element */
         if(H5FA_get(fa, u, elmt) < 0)
             H5E_THROW(H5E_CANTGET, "unable to delete fixed array")
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 6ca7aa4..71e9fe1 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -58,27 +58,24 @@ static char H5FD_mpi_native_g[] = "native";
  * driver doesn't bother to keep it updated since it's an expensive operation.
  */
 typedef struct H5FD_mpio_t {
-    H5FD_t	pub;		/*public stuff, must be first		*/
-    MPI_File	f;		/*MPIO file handle			*/
-    MPI_Comm	comm;		/*communicator				*/
-    MPI_Info	info;		/*file information			*/
-    int         mpi_rank;       /* This process's rank                  */
-    int         mpi_size;       /* Total number of processes            */
-    haddr_t	eof;		/*end-of-file marker			*/
-    haddr_t	eoa;		/*end-of-address marker			*/
-    haddr_t	last_eoa;	/* Last known end-of-address marker	*/
-    haddr_t	local_eof;	/* Local end-of-file address for each process */
+    H5FD_t      pub;        /* Public stuff, must be first                  */
+    MPI_File    f;          /* MPIO file handle                             */
+    MPI_Comm    comm;       /* MPI Communicator                             */
+    MPI_Info    info;       /* MPI info object                              */
+    int         mpi_rank;   /* This process's rank                          */
+    int         mpi_size;   /* Total number of processes                    */
+    haddr_t     eof;        /* End-of-file marker                           */
+    haddr_t     eoa;        /* End-of-address marker                        */
+    haddr_t     last_eoa;   /* Last known end-of-address marker             */
+    haddr_t     local_eof;  /* Local end-of-file address for each process   */
 } H5FD_mpio_t;
 
 /* Private Prototypes */
 
 /* Callbacks */
 static herr_t H5FD__mpio_term(void);
-static void *H5FD__mpio_fapl_get(H5FD_t *_file);
-static void *H5FD__mpio_fapl_copy(const void *_old_fa);
-static herr_t H5FD__mpio_fapl_free(void *_fa);
 static H5FD_t *H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
-			      haddr_t maxaddr);
+            haddr_t maxaddr);
 static herr_t H5FD__mpio_close(H5FD_t *_file);
 static herr_t H5FD__mpio_query(const H5FD_t *_f1, unsigned long *flags);
 static haddr_t H5FD__mpio_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
@@ -106,10 +103,10 @@ static const H5FD_class_mpi_t H5FD_mpio_g = {
     NULL,					/*sb_size		*/
     NULL,					/*sb_encode		*/
     NULL,					/*sb_decode		*/
-    sizeof(H5FD_mpio_fapl_t),			/*fapl_size		*/
-    H5FD__mpio_fapl_get,			/*fapl_get		*/
-    H5FD__mpio_fapl_copy,			/*fapl_copy		*/
-    H5FD__mpio_fapl_free, 			/*fapl_free		*/
+    0,			/*fapl_size		*/
+    NULL,			/*fapl_get		*/
+    NULL,			/*fapl_copy		*/
+    NULL, 			/*fapl_free		*/
     0,		                		/*dxpl_size		*/
     NULL,					/*dxpl_copy		*/
     NULL,					/*dxpl_free		*/
@@ -306,7 +303,6 @@ H5FD__mpio_term(void)
 herr_t
 H5Pset_fapl_mpio(hid_t fapl_id, MPI_Comm comm, MPI_Info info)
 {
-    H5FD_mpio_fapl_t    fa;
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t ret_value;
 
@@ -319,15 +315,16 @@ H5Pset_fapl_mpio(hid_t fapl_id, MPI_Comm comm, MPI_Info info)
     if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a file access list")
     if(MPI_COMM_NULL == comm)
-        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a valid communicator")
+        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "MPI_COMM_NULL is not a valid communicator")
 
-    /* Initialize driver specific properties */
-    HDmemset(&fa, 0, sizeof(H5FD_mpio_fapl_t));
-    fa.comm = comm;
-    fa.info = info;
+    /* Set the MPI communicator and info object */
+    if(H5P_set(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, &comm) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI communicator")
+    if(H5P_set(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI info object")
 
     /* duplication is done during driver setting. */
-    ret_value = H5P_set_driver(plist, H5FD_MPIO, &fa);
+    ret_value = H5P_set_driver(plist, H5FD_MPIO, NULL);
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -361,52 +358,43 @@ herr_t
 H5Pget_fapl_mpio(hid_t fapl_id, MPI_Comm *comm/*out*/, MPI_Info *info/*out*/)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
-    const H5FD_mpio_fapl_t *fa;       /* MPIO fapl info */
-    MPI_Comm    comm_tmp = MPI_COMM_NULL;
-    hbool_t     comm_copied = FALSE;    /* MPI Comm has been duplicated */
-    int         mpi_code;               /* MPI return code */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE3("e", "ixx", fapl_id, comm, info);
 
+    /* Set comm and info in case we have problems */
+    if(comm)
+        *comm = MPI_COMM_NULL;
+    if(info)
+        *info = MPI_INFO_NULL;
+
     /* Check arguments */
     if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "not a file access list")
     if(H5FD_MPIO != H5P_peek_driver(plist))
-        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "incorrect VFL driver")
-    if(NULL == (fa = (const H5FD_mpio_fapl_t *)H5P_peek_driver_info(plist)))
-        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "bad VFL driver info")
-
-    /* Store the duplicated communicator in a temporary variable for error */
-    /* recovery in case the INFO duplication fails. */
-    if(comm) {
-        if(MPI_SUCCESS != (mpi_code = MPI_Comm_dup(fa->comm, &comm_tmp)))
-            HMPI_GOTO_ERROR(FAIL, "MPI_Comm_dup failed", mpi_code)
-        comm_copied = TRUE;
-    } /* end if */
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "VFL driver is not MPI-I/O")
 
-    if(info) {
-        if(MPI_INFO_NULL != fa->info) {
-            if(MPI_SUCCESS != (mpi_code = MPI_Info_dup(fa->info, info)))
-                HMPI_GOTO_ERROR(FAIL, "MPI_Info_dup failed", mpi_code)
-        } /* end if */
-        else
-            /* do not dup it */
-            *info = MPI_INFO_NULL;
-    } /* end if */
-
-    /* Store the copied communicator, now that the Info object has been
-     *  successfully copied.
-     */
+    /* Get the MPI communicator and info object */
     if(comm)
-        *comm = comm_tmp;
+        if(H5P_get(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, comm) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get MPI communicator")
+    if(info)
+        if(H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, info) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get MPI info object")
 
 done:
-    if(ret_value < 0)
-        /* need to free anything created here */
-        if(comm_copied)
-            MPI_Comm_free(&comm_tmp);
+    /* Clean up anything duplicated on errors. The free calls will set
+     * the output values to MPI_COMM|INFO_NULL.
+     */
+    if(ret_value != SUCCEED) {
+        if(comm)
+            if(H5_mpi_comm_free(comm) < 0)
+                HDONE_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI communicator")
+        if(info)
+            if(H5_mpi_info_free(info) < 0)
+                HDONE_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI info object")
+    }
 
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_fapl_mpio() */
@@ -667,161 +655,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5FD__mpio_fapl_get
- *
- * Purpose:     Returns a file access property list which could be used to
- *              create another file the same as this one.
- *
- * Return:      Success:    Ptr to new file access property list with all
- *                          fields copied from the file pointer.
- *              Failure:    NULL
- *
- * Programmer:  Robb Matzke
- *              Friday, August 13, 1999
- *
- *-------------------------------------------------------------------------
- */
-static void *
-H5FD__mpio_fapl_get(H5FD_t *_file)
-{
-    H5FD_mpio_t         *file = (H5FD_mpio_t*)_file;
-    H5FD_mpio_fapl_t    *fa = NULL;
-    void                *ret_value = NULL;       /* Return value */
-
-    FUNC_ENTER_STATIC
-
-    /* Sanity checks */
-    HDassert(file);
-    HDassert(H5FD_MPIO == file->pub.driver_id);
-
-    /* Check arguments */
-    if(NULL == (fa = (H5FD_mpio_fapl_t *)H5MM_calloc(sizeof(H5FD_mpio_fapl_t))))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-    fa->comm = MPI_COMM_NULL;
-    fa->info = MPI_INFO_NULL;
-
-    /* Duplicate MPI communicator and info */
-    if(FAIL == H5_mpi_comm_dup(file->comm, &fa->comm))
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "communicator duplicate failed")
-    if(FAIL == H5_mpi_info_dup(file->info, &fa->info))
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "info duplicate failed")
-
-    /* Set return value */
-    ret_value = fa;
-
-done:
-    /* Clean up badness if we're failing */
-    if(NULL == ret_value && fa) {
-        H5_mpi_comm_free(&fa->comm);
-        H5_mpi_info_free(&fa->info);
-        H5MM_xfree(fa);
-    }
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD__mpio_fapl_get() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5FD__mpio_fapl_copy
- *
- * Purpose:     Copies the mpio-specific file access properties.
- *
- * Return:      Success:    Ptr to a new property list
- *              Failure:    NULL
- *
- * Programmer:  Albert Cheng
- *              Jan  8, 2003
- *
- *-------------------------------------------------------------------------
- */
-static void *
-H5FD__mpio_fapl_copy(const void *_old_fa)
-{
-    const H5FD_mpio_fapl_t  *old_fa = (const H5FD_mpio_fapl_t*)_old_fa;
-    H5FD_mpio_fapl_t        *new_fa = NULL;
-    void                    *ret_value = NULL;
-
-    FUNC_ENTER_STATIC
-
-#ifdef H5FDmpio_DEBUG
-if(H5FD_mpio_Debug[(int)'t'])
-    HDfprintf(stderr, "%s: entering\n", FUNC);
-#endif
-
-    if(NULL == (new_fa = (H5FD_mpio_fapl_t *)H5MM_malloc(sizeof(H5FD_mpio_fapl_t))))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-    /* Copy the general information */
-    H5MM_memcpy(new_fa, old_fa, sizeof(H5FD_mpio_fapl_t));
-
-    /* Duplicate MPI communicator and info */
-    if(H5_mpi_comm_dup(old_fa->comm, &new_fa->comm) < 0)
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "communicator duplicate failed")
-    if(H5_mpi_info_dup(old_fa->info, &new_fa->info) < 0)
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "info duplicate failed")
-
-    /* Set return value */
-    ret_value = new_fa;
-
-done:
-    /* Clean up badness if we're failing */
-    if(NULL == ret_value && new_fa) {
-        H5_mpi_comm_free(&new_fa->comm);
-        H5_mpi_info_free(&new_fa->info);
-        H5MM_xfree(new_fa);
-    }
-
-#ifdef H5FDmpio_DEBUG
-if(H5FD_mpio_Debug[(int)'t'])
-    HDfprintf(stderr, "%s: leaving\n", FUNC);
-#endif
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD__mpio_fapl_copy() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5FD__mpio_fapl_free
- *
- * Purpose:     Frees the mpio-specific file access properties.
- *
- * Return:      SUCCEED/FAIL
- *
- * Programmer:  Albert Cheng
- *              Jan  8, 2003
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__mpio_fapl_free(void *_fa)
-{
-    H5FD_mpio_fapl_t    *fa = (H5FD_mpio_fapl_t*)_fa;
-
-    FUNC_ENTER_STATIC_NOERR
-
-#ifdef H5FDmpio_DEBUG
-if(H5FD_mpio_Debug[(int)'t'])
-    HDfprintf(stderr, "%s: Entering\n", FUNC);
-#endif
-
-    /* Sanity checks */
-    HDassert(fa);
-
-    /* Free the internal communicator and INFO object */
-    HDassert(MPI_COMM_NULL != fa->comm);
-    H5_mpi_comm_free(&fa->comm);
-    H5_mpi_info_free(&fa->info);
-    H5MM_xfree(fa);
-
-#ifdef H5FDmpio_DEBUG
-if(H5FD_mpio_Debug[(int)'t'])
-    HDfprintf(stderr, "%s: leaving\n", FUNC);
-#endif
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5FD__mpio_fapl_free() */
-
-
-/*-------------------------------------------------------------------------
  * Function:    H5FD_set_mpio_atomicity
  *
  * Purpose:     Sets the atomicity mode
@@ -935,20 +768,18 @@ static H5FD_t *
 H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
     haddr_t H5_ATTR_UNUSED maxaddr)
 {
-    H5FD_mpio_t			*file = NULL;
-    MPI_File			fh;
-    unsigned                    file_opened = 0; /* Flag to indicate that the file was successfully opened */
-    int				mpi_amode;
-    int				mpi_rank;       /* MPI rank of this process */
-    int				mpi_size;       /* Total number of MPI processes */
-    int				mpi_code;	/* mpi return code */
-    MPI_Offset			size;
-    const H5FD_mpio_fapl_t	*fa = NULL;
-    H5FD_mpio_fapl_t		_fa;
+    H5FD_mpio_t     *file = NULL;
+    MPI_File        fh;
+    hbool_t         file_opened = FALSE; /* Flag to indicate that the file was successfully opened */
+    int             mpi_amode;
+    int             mpi_rank;       /* MPI rank of this process */
+    int             mpi_size;       /* Total number of MPI processes */
+    int             mpi_code;       /* MPI return code */
+    MPI_Offset      size;
     H5P_genplist_t *plist;      /* Property list pointer */
-    MPI_Comm                    comm_dup = MPI_COMM_NULL;
-    MPI_Info                    info_dup = MPI_INFO_NULL;
-    H5FD_t			*ret_value = NULL;     /* Return value */
+    MPI_Comm        comm = MPI_COMM_NULL;
+    MPI_Info        info = MPI_INFO_NULL;
+    H5FD_t          *ret_value = NULL;     /* Return value */
 
     FUNC_ENTER_STATIC
 
@@ -957,26 +788,18 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
         HDfprintf(stdout, "%s: Entering - name = \"%s\", flags = 0x%x, fapl_id = %d, maxaddr = %lu\n", FUNC, name, flags, (int)fapl_id, (unsigned long)maxaddr);
 #endif
 
-    /* Obtain a pointer to mpio-specific file access properties */
+    /* Get a pointer to the fapl */
     if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a file access property list")
-    if(H5P_FILE_ACCESS_DEFAULT == fapl_id || H5FD_MPIO != H5P_peek_driver(plist)) {
-        _fa.comm = MPI_COMM_SELF; /*default*/
-        _fa.info = MPI_INFO_NULL; /*default*/
-        fa = &_fa;
-    } /* end if */
-    else
-        if(NULL == (fa = (const H5FD_mpio_fapl_t *)H5P_peek_driver_info(plist)))
-            HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, NULL, "bad VFL driver info")
 
-    /* Duplicate MPI communicator and info */
-    if(FAIL == H5_mpi_comm_dup(fa->comm, &comm_dup))
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "communicator duplicate failed")
-    if(FAIL == H5_mpi_info_dup(fa->info, &info_dup))
-        HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "info duplicate failed")
+    /* Get the MPI communicator and info object from the property list */
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, &comm) < 0)
+        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI communicator")
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI info object")
 
-    /* convert HDF5 flags to MPI-IO flags */
-    /* some combinations are illegal; let MPI-IO figure it out */
+    /* Convert HDF5 flags to MPI-IO flags */
+    /* Some combinations are illegal; let MPI-IO figure it out */
     mpi_amode  = (flags & H5F_ACC_RDWR) ? MPI_MODE_RDWR : MPI_MODE_RDONLY;
     if(flags & H5F_ACC_CREAT)
         mpi_amode |= MPI_MODE_CREATE;
@@ -985,11 +808,11 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
 
 #ifdef H5FDmpio_DEBUG
     /* Check for debug commands in the info parameter */
-    if(MPI_INFO_NULL != info_dup) {
+    if(MPI_INFO_NULL != info) {
         char debug_str[128];
         int flag;
 
-        MPI_Info_get(fa->info, H5F_MPIO_DEBUG_KEY, sizeof(debug_str) - 1, debug_str, &flag);
+        MPI_Info_get(info, H5F_MPIO_DEBUG_KEY, sizeof(debug_str) - 1, debug_str, &flag);
         if(flag) {
             int i;
 
@@ -1000,22 +823,22 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
     } /* end if */
 #endif
 
-    if(MPI_SUCCESS != (mpi_code = MPI_File_open(comm_dup, name, mpi_amode, info_dup, &fh)))
+    if(MPI_SUCCESS != (mpi_code = MPI_File_open(comm, name, mpi_amode, info, &fh)))
         HMPI_GOTO_ERROR(NULL, "MPI_File_open failed", mpi_code)
-    file_opened=1;
+    file_opened = TRUE;
 
     /* Get the MPI rank of this process and the total number of processes */
-    if (MPI_SUCCESS != (mpi_code=MPI_Comm_rank (comm_dup, &mpi_rank)))
+    if (MPI_SUCCESS != (mpi_code = MPI_Comm_rank (comm, &mpi_rank)))
         HMPI_GOTO_ERROR(NULL, "MPI_Comm_rank failed", mpi_code)
-    if (MPI_SUCCESS != (mpi_code=MPI_Comm_size (comm_dup, &mpi_size)))
+    if (MPI_SUCCESS != (mpi_code = MPI_Comm_size (comm, &mpi_size)))
         HMPI_GOTO_ERROR(NULL, "MPI_Comm_size failed", mpi_code)
 
     /* Build the return value and initialize it */
     if(NULL == (file = (H5FD_mpio_t *)H5MM_calloc(sizeof(H5FD_mpio_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
     file->f = fh;
-    file->comm = comm_dup;
-    file->info = info_dup;
+    file->comm = comm;
+    file->info = info;
     file->mpi_rank = mpi_rank;
     file->mpi_size = mpi_size;
 
@@ -1026,7 +849,7 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
     } /* end if */
 
     /* Broadcast file size */
-    if(MPI_SUCCESS != (mpi_code = MPI_Bcast(&size, (int)sizeof(MPI_Offset), MPI_BYTE, 0, comm_dup)))
+    if(MPI_SUCCESS != (mpi_code = MPI_Bcast(&size, (int)sizeof(MPI_Offset), MPI_BYTE, 0, comm)))
         HMPI_GOTO_ERROR(NULL, "MPI_Bcast failed", mpi_code)
 
     /* Determine if the file should be truncated */
@@ -1035,7 +858,7 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
             HMPI_GOTO_ERROR(NULL, "MPI_File_set_size failed", mpi_code)
 
         /* Don't let any proc return until all have truncated the file. */
-        if (MPI_SUCCESS!= (mpi_code=MPI_Barrier(comm_dup)))
+        if (MPI_SUCCESS != (mpi_code = MPI_Barrier(comm)))
             HMPI_GOTO_ERROR(NULL, "MPI_Barrier failed", mpi_code)
 
         /* File is zero size now */
@@ -1053,8 +876,10 @@ done:
     if(ret_value == NULL) {
         if(file_opened)
             MPI_File_close(&fh);
-        MPI_Comm_free(&comm_dup);
-        MPI_Info_free(&info_dup);
+        if(H5_mpi_comm_free(&comm) < 0)
+            HDONE_ERROR(H5E_VFL, H5E_CANTFREE, NULL, "unable to free MPI communicator")
+        if(H5_mpi_info_free(&info) < 0)
+            HDONE_ERROR(H5E_VFL, H5E_CANTFREE, NULL, "unable to free MPI info object")
         if(file)
             H5MM_xfree(file);
     } /* end if */
@@ -1282,37 +1107,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:       H5FD_mpio_get_info
- *
- * Purpose:        Returns the file info of MPIO file driver.
- *
- * Returns:        SUCCEED/FAIL
- *
- * Programmer:     John Mainzer
- *                 April 4, 2017
- *
- *-------------------------------------------------------------------------
-*/
-static herr_t
-H5FD_mpio_get_info(H5FD_t *_file, void** mpi_info)
-{
-    H5FD_mpio_t         *file = (H5FD_mpio_t *)_file;
-    herr_t              ret_value = SUCCEED;
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    if(!mpi_info)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "mpi info not valid")
-
-    *mpi_info = &(file->info);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-
-} /* H5FD_mpio_get_info() */
-
-
-/*-------------------------------------------------------------------------
  * Function:    H5FD__mpio_read
  *
  * Purpose:     Reads SIZE bytes of data from FILE beginning at address ADDR
@@ -1697,7 +1491,7 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id,
     io_size = type_size * size_i;
 
     /* Check for write failure */
-    if(bytes_written != io_size)
+    if(bytes_written != io_size || bytes_written < 0)
         HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed")
 
     /* Each process will keep track of its perceived EOF value locally, and
@@ -1708,8 +1502,8 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id,
      * potentially be wrong.) */
     file->eof = HADDR_UNDEF;
 
-    if(bytes_written && ((bytes_written + addr) > file->local_eof))
-        file->local_eof = addr + bytes_written;
+    if(bytes_written && (((haddr_t)bytes_written + addr) > file->local_eof))
+        file->local_eof = addr + (haddr_t)bytes_written;
 
 done:
 #ifdef H5FDmpio_DEBUG
diff --git a/src/H5FDprivate.h b/src/H5FDprivate.h
index 0db66af..ac08f7f 100644
--- a/src/H5FDprivate.h
+++ b/src/H5FDprivate.h
@@ -95,14 +95,6 @@ typedef struct {
     const void *driver_info;    /* Driver info, for open callbacks */
 } H5FD_driver_prop_t;
 
-#ifdef H5_HAVE_PARALLEL
-/* MPIO-specific file access properties */
-typedef struct H5FD_mpio_fapl_t {
-    MPI_Comm		comm;		/*communicator			*/
-    MPI_Info		info;		/*file information		*/
-} H5FD_mpio_fapl_t;
-#endif /* H5_HAVE_PARALLEL */
-
 
 /*****************************/
 /* Library Private Variables */
diff --git a/src/H5FDros3.c b/src/H5FDros3.c
index 18f1f91..a369ca2 100644
--- a/src/H5FDros3.c
+++ b/src/H5FDros3.c
@@ -34,6 +34,8 @@
 #include "H5MMprivate.h"    /* Memory management        */
 #include "H5FDs3comms.h"    /* S3 Communications        */
 
+#ifdef H5_HAVE_ROS3_VFD
+
 /* toggle function call prints: 1 turns on
  */
 #define ROS3_DEBUG 0
@@ -119,8 +121,6 @@ static unsigned long long ros3_stats_boundaries[ROS3_STATS_BIN_COUNT];
  *
  * Programmer: Jacob Smith
  *
- * Changes: None
- *
  ***************************************************************************/
 typedef struct {
     unsigned long long count;
@@ -190,8 +190,6 @@ typedef struct {
  *
  * Programmer: Jacob Smith
  *
- * Changes: None.
- *
  ***************************************************************************/
 typedef struct H5FD_ros3_t {
     H5FD_t            pub;
@@ -215,9 +213,7 @@ typedef struct H5FD_ros3_t {
  *
  */
 #define MAXADDR (((haddr_t)1<<(8*sizeof(HDoff_t)-1))-1)
-#ifdef H5_HAVE_ROS3_VFD
 #define ADDR_OVERFLOW(A)    (HADDR_UNDEF==(A) || ((A) & ~(haddr_t)MAXADDR))
-#endif /* H5_HAVE_ROS3_VFD */
 
 /* Prototypes */
 static herr_t  H5FD_ros3_term(void);
@@ -279,10 +275,8 @@ static const H5FD_class_t H5FD_ros3_g = {
     H5FD_FLMAP_DICHOTOMY        /* fl_map               */
 };
 
-#ifdef H5_HAVE_ROS3_VFD
 /* Declare a free list to manage the H5FD_ros3_t struct */
 H5FL_DEFINE_STATIC(H5FD_ros3_t);
-#endif /* H5_HAVE_ROS3_VFD */
 
 
 /*-------------------------------------------------------------------------
@@ -292,8 +286,7 @@ H5FL_DEFINE_STATIC(H5FD_ros3_t);
  *
  * Return:      Non-negative on success/Negative on failure
  *
- * Changes:     Rename as appropriate for ros3 vfd.
- *              Jacob Smith 2017
+ * Programmer:  Jacob Smith 2017
  *
  *-------------------------------------------------------------------------
  */
@@ -324,11 +317,7 @@ done:
  * Return:      Success:    The driver ID for the ros3 driver.
  *              Failure:    Negative
  *
- * Programmer:  Robb Matzke
- *              Thursday, July 29, 1999
- *
- * Changes:     Rename as appropriate for ros3 vfd.
- *              Jacob Smith 2017
+ * Programmer:  Jacob Smith 2017
  *
  *-------------------------------------------------------------------------
  */
@@ -372,11 +361,7 @@ done:
  *
  * Returns:     SUCCEED (Can't fail)
  *
- * Programmer:  Quincey Koziol
- *              Friday, Jan 30, 2004
- *
- * Changes:     Rename as appropriate for ros3 vfd.
- *              Jacob Smith 2017
+ * Programmer:  Jacob Smith 2017
  *
  *---------------------------------------------------------------------------
  */
@@ -464,10 +449,6 @@ done:
  * Programmer:  Jacob Smith
  *              9/10/17
  *
- * Changes:     Add checks for authenticate flag requring populated
- *              `aws_region` and `secret_id` strings.
- *                  -- Jacob Smith 2017-11-01
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -479,7 +460,7 @@ H5FD_ros3_validate_config(const H5FD_ros3_fapl_t * fa)
 
     HDassert(fa != NULL);
 
-    if ( fa->version != H5FD__CURR_ROS3_FAPL_T_VERSION ) {
+    if ( fa->version != H5FD_CURR_ROS3_FAPL_T_VERSION ) {
          HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                      "Unknown H5FD_ros3_fapl_t version");
     }
@@ -704,8 +685,6 @@ H5FD_ros3_fapl_free(void *_fa)
  * Programmer: Jacob Smith
  *             2017-12-08
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 static herr_t
@@ -774,12 +753,8 @@ done:
  * Programmer: Jacob Smith
  *             2017-11-02
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
-
 static H5FD_t *
 H5FD_ros3_open(
         const char *url,
@@ -904,22 +879,6 @@ done:
 
 } /* end H5FD_ros3_open() */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-static H5FD_t *
-H5FD_ros3_open(
-        const char H5_ATTR_UNUSED *url,
-        unsigned   H5_ATTR_UNUSED  flags,
-        hid_t      H5_ATTR_UNUSED  fapl_id,
-        haddr_t    H5_ATTR_UNUSED  maxaddr)
-{
-    H5FD_t *ret_value = NULL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FD_ros3_open() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 #if ROS3_STATS
 
 /*----------------------------------------------------------------------------
@@ -974,8 +933,6 @@ H5FD_ros3_open(
  *
  * Programmer: Jacob Smith
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 static herr_t
@@ -1228,12 +1185,8 @@ done:
  * Programmer: Jacob Smith
  *             2017-11-02
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
-
 static herr_t
 H5FD_ros3_close(H5FD_t H5_ATTR_UNUSED *_file)
 {
@@ -1277,18 +1230,6 @@ done:
 
 } /* end H5FD_ros3_close() */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-static herr_t
-H5FD_ros3_close(H5FD_t H5_ATTR_UNUSED *_file)
-{
-    herr_t ret_value = FAIL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD_ros3_close() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 
 /*-------------------------------------------------------------------------
  *
@@ -1318,17 +1259,8 @@ H5FD_ros3_close(H5FD_t H5_ATTR_UNUSED *_file)
  * Programmer: Jacob Smith
  *             2017-11-06
  *
- * Changes:
- *
- *     + Change from strcmp-like return values (-1, 0, 1) to instead return
- *       binary equivalence (0) or inequality (-1).
- *     + Replace "if still equal then check this" waterfall with GOTO jumps.
- *     Jacob Smith 2018-05-17
- *
  *-------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
-
 static int
 H5FD_ros3_cmp(
         const H5FD_t *_f1,
@@ -1463,20 +1395,6 @@ done:
 
 } /* H5FD_ros3_cmp() */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-static int
-H5FD_ros3_cmp(
-        const H5FD_t H5_ATTR_UNUSED *_f1,
-        const H5FD_t H5_ATTR_UNUSED *_f2)
-{
-    int                 ret_value = 0;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FD_ros3_cmp() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 
 /*-------------------------------------------------------------------------
  * Function:    H5FD_ros3_query
@@ -1536,8 +1454,6 @@ H5FD_ros3_query(const H5FD_t H5_ATTR_UNUSED *_file,
  * Programmer: Jacob Smith
  *             2017-11-02
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
@@ -1572,8 +1488,6 @@ H5FD_ros3_get_eoa(const H5FD_t                *_file,
  * Programmer: Jacob Smith
  *             2017-11-03
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1646,8 +1560,6 @@ H5FD_ros3_get_eof(const H5FD_t                *_file,
  * Programmer: Jacob Smith
  *             2017-11-02
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1696,8 +1608,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-11-??
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1792,8 +1702,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-10-23
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1839,8 +1747,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-10-23
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1884,8 +1790,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-11-03
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1914,8 +1818,6 @@ H5FD_ros3_lock(H5FD_t  H5_ATTR_UNUSED *_file,
  * Programmer: Jacob Smith
  *             2017-11-03
  *
- * Changes: None.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1926,4 +1828,5 @@ H5FD_ros3_unlock(H5FD_t H5_ATTR_UNUSED *_file)
 
 } /* end H5FD_ros3_unlock() */
 
+#endif /* H5_HAVE_ROS3_VFD */
 
diff --git a/src/H5FDros3.h b/src/H5FDros3.h
index 7dfc95b..250c7cc 100644
--- a/src/H5FDros3.h
+++ b/src/H5FDros3.h
@@ -21,11 +21,13 @@
 #ifndef H5FDros3_H
 #define H5FDros3_H
 
-#define H5FD_ROS3 (H5FD_ros3_init())
+#ifdef H5_HAVE_ROS3_VFD
+#define H5FD_ROS3               (H5FD_ros3_init())
+#else
+#define H5FD_ROS3               (H5I_INVALID_HID)
+#endif /* H5_HAVE_ROS3_VFD */
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+#ifdef H5_HAVE_ROS3_VFD
 
 /****************************************************************************
  *
@@ -46,7 +48,7 @@ extern "C" {
  *     to the above calls must have a recognized version number, or an error
  *     will be flagged.
  *
- *     This field should be set to H5FD__CURR_ROS3_FAPL_T_VERSION.
+ *     This field should be set to H5FD_CURR_ROS3_FAPL_T_VERSION.
  *
  * `authenticate` (hbool_t)
  *
@@ -67,31 +69,27 @@ extern "C" {
  *
  *     String: "Secret Access Key" associated with the ID and resource.
  *
- *
- *
- * Programmer: John Mainzer
- *
- * Changes:
- *
- *     - Add documentation of fields (except `version`)
- *     --- Jacob Smith 2017-12-04
- *
  ****************************************************************************/
 
-#define H5FD__CURR_ROS3_FAPL_T_VERSION     1
+#define H5FD_CURR_ROS3_FAPL_T_VERSION     1
 
-#define H5FD__ROS3_MAX_REGION_LEN         32
-#define H5FD__ROS3_MAX_SECRET_ID_LEN     128
-#define H5FD__ROS3_MAX_SECRET_KEY_LEN    128
+#define H5FD_ROS3_MAX_REGION_LEN         32
+#define H5FD_ROS3_MAX_SECRET_ID_LEN     128
+#define H5FD_ROS3_MAX_SECRET_KEY_LEN    128
 
 typedef struct H5FD_ros3_fapl_t {
     int32_t version;
     hbool_t authenticate;
-    char    aws_region[H5FD__ROS3_MAX_REGION_LEN + 1];
-    char    secret_id[H5FD__ROS3_MAX_SECRET_ID_LEN + 1];
-    char    secret_key[H5FD__ROS3_MAX_SECRET_KEY_LEN + 1];
+    char    aws_region[H5FD_ROS3_MAX_REGION_LEN + 1];
+    char    secret_id[H5FD_ROS3_MAX_SECRET_ID_LEN + 1];
+    char    secret_key[H5FD_ROS3_MAX_SECRET_KEY_LEN + 1];
 } H5FD_ros3_fapl_t;
 
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 H5_DLL hid_t H5FD_ros3_init(void);
 H5_DLL herr_t H5Pget_fapl_ros3(hid_t fapl_id, H5FD_ros3_fapl_t * fa_out);
 H5_DLL herr_t H5Pset_fapl_ros3(hid_t fapl_id, H5FD_ros3_fapl_t * fa);
@@ -100,6 +98,8 @@ H5_DLL herr_t H5Pset_fapl_ros3(hid_t fapl_id, H5FD_ros3_fapl_t * fa);
 }
 #endif
 
+#endif /* H5_HAVE_ROS3_VFD */
+
 #endif /* ifndef H5FDros3_H */
 
 
diff --git a/src/H5FDs3comms.c b/src/H5FDs3comms.c
index 42b281f..f8b4417 100644
--- a/src/H5FDs3comms.c
+++ b/src/H5FDs3comms.c
@@ -47,12 +47,12 @@
 /* Local Macros */
 /****************/
 
+#ifdef H5_HAVE_ROS3_VFD
+
 /* toggle debugging (enable with 1)
  */
 #define S3COMMS_DEBUG 0
 
-#ifdef H5_HAVE_ROS3_VFD
-
 /* manipulate verbosity of CURL output
  * operates separately from S3COMMS_DEBUG
  *
@@ -67,7 +67,6 @@
  */
 #define S3COMMS_MAX_RANGE_STRING_SIZE 128
 
-#endif /* H5_HAVE_ROS3_VFD */
 
 /******************/
 /* Local Typedefs */
@@ -137,8 +136,6 @@ herr_t H5FD_s3comms_s3r_getsize(s3r_t *handle);
  * Programmer: Jacob Smith
  *             2017-08-17
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 size_t
@@ -217,14 +214,6 @@ curlwritecallback(char   *ptr,
  * Programmer: Jacob Smith
  *             2017-09-22
  *
- * Changes:
- *
- *     - Change return value to herr_t
- *     - Change list pointer to pointer-to-pointer-to-node
- *     - Change to use singly-linked list (from twin doubly-linked lists)
- *       with modification to hrb_node_t
- *     --- Jake Smith 2017-01-17
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -635,19 +624,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-21
  *
- * Changes:
- *
- *     - Conditional free() of `hrb_node_t` pointer properties based on
- *       `which_free` property.
- *     --- Jacob Smith 2017-08-08
- *
- *     - Integrate with HDF5.
- *     - Returns herr_t instead of nothing.
- *     --- Jacob Smith 2017-09-21
- *
- *     - Change argument to from *buf to **buf, to null pointer within call
- *     --- Jacob Smith 2017-20-05
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -709,25 +685,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-21
  *
- * Changes:
- *
- *     - Update struct membership for newer 'generic' `hrb_t` format.
- *     --- Jacob Smith, 2017-07-24
- *
- *     - Rename from `hrb_new()` to `hrb_request()`
- *     --- Jacob Smith, 2017-07-25
- *
- *     - Integrate with HDF5.
- *     - Rename from 'hrb_request()` to `H5FD_s3comms_hrb_init_request()`.
- *     - Remove `host` from input parameters.
- *         - Host, as with all other fields, must now be added through the
- *           add-field functions.
- *     - Add `version` (HTTP version string, e.g. "HTTP/1.1") to parameters.
- *     --- Jacob Smith 2017-09-20
- *
- *     - Update to use linked-list `hrb_node_t` headers in structure.
- *     --- Jacob Smith 2017-10-05
- *
  *----------------------------------------------------------------------------
  */
 hrb_t *
@@ -842,64 +799,10 @@ done:
 } /* end H5FD_s3comms_hrb_init_request() */
 
 
-
 /****************************************************************************
  * S3R FUNCTIONS
  ****************************************************************************/
 
-#ifndef H5_HAVE_ROS3_VFD
-/* No-op, auto-fail, unused-variable implementations if ROS3 is not enabled */
-
-herr_t
-H5FD_s3comms_s3r_close(s3r_t H5_ATTR_UNUSED *handle)
-{
-    herr_t ret_value = SUCCEED;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD_s3comms_s3r_close() */
-
-size_t
-H5FD_s3comms_s3r_get_filesize(s3r_t H5_ATTR_UNUSED *handle)
-{
-    size_t ret_value = 0;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD_s3comms_s3r_get_filesize() */
-
-herr_t
-H5FD_s3comms_s3r_getsize(s3r_t H5_ATTR_UNUSED *handle)
-{
-    herr_t ret_value = FAIL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5FD_s3comms_s3r_getsize() */
-
-s3r_t *
-H5FD_s3comms_s3r_open(
-        const char          H5_ATTR_UNUSED *url,
-        const char          H5_ATTR_UNUSED *region,
-        const char          H5_ATTR_UNUSED *id,
-        const unsigned char H5_ATTR_UNUSED *signing_key)
-{
-    s3r_t        *ret_value = NULL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD_s3comms_s3r_open() */
-
-herr_t
-H5FD_s3comms_s3r_read(
-        s3r_t   H5_ATTR_UNUSED *handle,
-        haddr_t H5_ATTR_UNUSED  offset,
-        size_t  H5_ATTR_UNUSED  len,
-        void    H5_ATTR_UNUSED *dest)
-{
-    herr_t ret_value = FAIL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5FD_s3comms_s3r_read() */
-
-#else
-
 
 /*----------------------------------------------------------------------------
  *
@@ -920,20 +823,6 @@ H5FD_s3comms_s3r_read(
  * Programmer: Jacob Smith
  *             2017-08-31
  *
- * Changes:
- *
- *    - Remove all messiness related to the now-gone "setopt" utility
- *      as it no longer exists in the handle.
- *    - Return type to `void`.
- *    --- Jacob Smith 2017-09-01
- *
- *    - Incorporate into HDF environment.
- *    - Rename from `s3r_close()` to `H5FD_s3comms_s3r_close()`.
- *    --- Jacob Smith 2017-10-06
- *
- *    - Change separate host, resource, port info to `parsed_url_t` struct ptr.
- *    --- Jacob Smith 2017-11-01
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -995,8 +884,6 @@ done:
  *
  * Programmer: Jacob Smith 2017-01-14
  *
- * Changes: None
- *
  *----------------------------------------------------------------------------
  */
 size_t
@@ -1044,44 +931,24 @@ H5FD_s3comms_s3r_get_filesize(s3r_t *handle)
  * Programmer: Jacob Smith
  *             2017-08-23
  *
- * Changes:
- *
- *     - Update to revised `s3r_t` format and life cycle.
- *     --- Jacob Smith 2017-09-01
- *
- *     - Conditional change to static header buffer and structure.
- *     --- Jacob Smith 2017-09-05
- *
- *     - Incorporate into HDF environment.
- *     - Rename from `s3r_getsize()` to `H5FD_s3comms_s3r_getsize()`.
- *     --- Jacob Smith 2017-10-06
- *
  *----------------------------------------------------------------------------
  */
 herr_t
 H5FD_s3comms_s3r_getsize(s3r_t *handle)
 {
-#ifdef H5_HAVE_ROS3_VFD
     uintmax_t             content_length = 0;
     CURL                  *curlh          = NULL;
     char                  *end            = NULL;
     char                  *headerresponse = NULL;
-    herr_t                 ret_value      = SUCCEED;
     struct s3r_datastruct  sds            = {
             S3COMMS_CALLBACK_DATASTRUCT_MAGIC,
             NULL,
             0 };
     char                  *start          = NULL;
-#else
-    herr_t                 ret_value      = FAIL;
-#endif /* H5_HAVE_ROS3_VFD */
-
-
+    herr_t                 ret_value      = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-#ifdef H5_HAVE_ROS3_VFD
-
 #if S3COMMS_DEBUG
     HDfprintf(stdout, "called H5FD_s3comms_s3r_getsize.\n");
 #endif
@@ -1238,8 +1105,6 @@ done:
     H5MM_xfree(headerresponse);
     sds.magic += 1; /* set to bad magic */
 
-#endif /* H5_HAVE_ROS3_VFD */
-
     FUNC_LEAVE_NOAPI(ret_value);
 
 } /* H5FD_s3comms_s3r_getsize */
@@ -1282,20 +1147,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-09-01
  *
- * Changes:
- *
- *     - Incorporate into HDF environment.
- *     - Rename from `s3r_open()` to `H5FD_s3comms_s3r_open()`.
- *     --- Jacob Smith 2017-10-06
- *
- *     - Remove port number from signature.
- *     - Name (`url`) must be complete url with http scheme and optional port
- *       number in string.
- *         - e.g., "http://bucket.aws.com:9000/myfile.dat?query=param"
- *     - Internal storage of host, resource, and port information moved into
- *       `parsed_url_t` struct pointer.
- *     --- Jacob Smith 2017-11-01
- *
  *----------------------------------------------------------------------------
  */
 s3r_t *
@@ -1304,20 +1155,14 @@ H5FD_s3comms_s3r_open(const char          *url,
                       const char          *id,
                       const unsigned char *signing_key)
 {
-#ifdef H5_HAVE_ROS3_VFD
     size_t        tmplen    = 0;
     CURL         *curlh     = NULL;
     s3r_t        *handle    = NULL;
     parsed_url_t *purl      = NULL;
-#endif
     s3r_t        *ret_value = NULL;
 
-
-
     FUNC_ENTER_NOAPI_NOINIT
 
-#ifdef H5_HAVE_ROS3_VFD
-
 #if S3COMMS_DEBUG
     HDfprintf(stdout, "called H5FD_s3comms_s3r_open.\n");
 #endif
@@ -1492,11 +1337,9 @@ H5FD_s3comms_s3r_open(const char          *url,
     HDmemcpy(handle->httpverb, "GET", 4);
 
     ret_value = handle;
-#endif /* H5_HAVE_ROS3_VFD */
 
 done:
     if (ret_value == NULL) {
-#ifdef H5_HAVE_ROS3_VFD
         if (curlh != NULL) {
             curl_easy_cleanup(curlh);
         }
@@ -1513,7 +1356,6 @@ done:
             }
             H5MM_xfree(handle);
         }
-#endif /* H5_HAVE_ROS3_VFD */
     }
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1560,29 +1402,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-08-22
  *
- * Changes:
- *
- *     - Revise structure to prevent unnecessary hrb_t element creation.
- *     - Rename tmprstr -> rangebytesstr to reflect purpose.
- *     - Insert needed `free()`s, particularly for `sds`.
- *     --- Jacob Smith 2017-08-23
- *
- *     - Revise heavily to accept buffer, range as parameters.
- *     - Utilize modified s3r_t format.
- *     --- Jacob Smith 2017-08-31
- *
- *     - Incorporate into HDF library.
- *     - Rename from `s3r_read()` to `H5FD_s3comms_s3r_read()`.
- *     - Return `herr_t` succeed/fail instead of S3code.
- *     - Update to use revised `hrb_t` and `hrb_node_t` structures.
- *     --- Jacob Smith 2017-10-06
- *
- *     - Update to use `parsed_url_t *purl` in handle.
- *     --- Jacob Smith 2017-11-01
- *
- *     - Better define behavior upon read past EOF
- *     --- Jacob Smith 2017-01-19
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -1591,7 +1410,6 @@ H5FD_s3comms_s3r_read(s3r_t   *handle,
                       size_t   len,
                       void    *dest)
 {
-#ifdef H5_HAVE_ROS3_VFD
     CURL                  *curlh         = NULL;
     CURLcode               p_status      = CURLE_OK;
     struct curl_slist     *curlheaders   = NULL;
@@ -1604,16 +1422,9 @@ H5FD_s3comms_s3r_read(s3r_t   *handle,
                                               /* return value of HDsnprintf  */
     struct s3r_datastruct *sds           = NULL;
     herr_t                 ret_value     = SUCCEED;
-#else
-    herr_t                 ret_value     = FAIL;
-#endif /* H5_HAVE_ROS3_VFD */
-
-
 
     FUNC_ENTER_NOAPI_NOINIT
 
-#ifdef H5_HAVE_ROS3_VFD
-
 #if S3COMMS_DEBUG
     HDfprintf(stdout, "called H5FD_s3comms_s3r_read.\n");
 #endif
@@ -2105,12 +1916,9 @@ done:
         }
     }
 
-#endif /* H5_HAVE_ROS3_VFD */
-
     FUNC_LEAVE_NOAPI(ret_value);
 } /* H5FD_s3comms_s3r_read */
 
-#endif /* H5_HAVE_ROS3_VFD */
 
 /****************************************************************************
  * MISCELLANEOUS FUNCTIONS
@@ -2133,8 +1941,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-12
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 struct tm *
@@ -2192,8 +1998,6 @@ gmnow(void)
  * Programmer: Jacob Smith
  *             2017-10-04
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -2362,20 +2166,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-12
  *
- * Changes:
- *
- *     - Integrate into HDF.
- *     - Rename from hex() to H5FD_s3comms_bytes_to_hex.
- *     - Change return type from `void` to `herr_t`.
- *     --- Jacob Smtih 2017-09-14
- *
- *     - Add bool parameter `lowercase` to configure upper/lowercase output
- *       of a-f hex characters.
- *     --- Jacob Smith 2017-09-19
- *
- *     - Change bool type to `hbool_t`
- *     --- Jacob Smtih 2017-10-11
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -2438,8 +2228,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-11-01
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -2494,22 +2282,8 @@ H5FD_s3comms_free_purl(parsed_url_t *purl)
  * Programmer: Jacob Smith
  *             2017-07-??
  *
- * Changes:
- *
- *     - Integrate with HDF5.
- *     - Rename from `HMAC_SHA256` to `H5FD_s3comms_HMAC_SHA256`.
- *     - Rename output parameter from `md` to `dest`.
- *     - Return `herr_t` type instead of `void`.
- *     - Call `H5FD_s3comms_bytes_to_hex` to generate hex cleartext for output.
- *     --- Jacob Smith 2017-09-19
- *
- *     - Use static char array instead of malloc'ing `md`
- *     --- Jacob Smith 2017-10-10
- *
  *----------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
-
 herr_t
 H5FD_s3comms_HMAC_SHA256(
         const unsigned char *key,
@@ -2556,23 +2330,6 @@ done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* H5FD_s3comms_HMAC_SHA256 */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-herr_t
-H5FD_s3comms_HMAC_SHA256(
-        const unsigned char H5_ATTR_UNUSED *key,
-        size_t              H5_ATTR_UNUSED  key_len,
-        const char          H5_ATTR_UNUSED *msg,
-        size_t              H5_ATTR_UNUSED  msg_len,
-        char                H5_ATTR_UNUSED *dest)
-{
-    herr_t ret_value = FAIL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5FD_s3comms_HMAC_SHA256() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 
 /*-----------------------------------------------------------------------------
  *
@@ -2621,8 +2378,6 @@ H5FD_s3comms_HMAC_SHA256(
  * Programmer: Jacob Smith
  *             2018-02-27
  *
- * Changes: None
- *
  *-----------------------------------------------------------------------------
  */
 static herr_t
@@ -2781,8 +2536,6 @@ done:
  * Programmer: Jacob Smith
  *             2018-02-27
  *
- * Changes: None
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -2903,8 +2656,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-09-18
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -2968,8 +2719,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-10-30
  *
- * Changes: None.
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -3242,12 +2991,6 @@ done:
  *
  * Programmer: Jacob Smith
  *
- * Changes:
- *
- *     - Integrate into HDF.
- *     - Rename from `hexutf8` to `H5FD_s3comms_percent_encode_char`.
- *     --- Jacob Smith 2017-09-15
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -3421,19 +3164,8 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-13
  *
- * Changes:
- *
- *     - Integrate into HDF5.
- *     - Return herr_t type.
- *     --- Jacob Smith 2017-09-18
- *
- *     - NULL check and fail of input parameters.
- *     --- Jacob Smith 2017-10-10
- *
  *----------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
-
 herr_t
 H5FD_s3comms_signing_key(
         unsigned char *md,
@@ -3526,22 +3258,6 @@ done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5FD_s3comms_signing_key() */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-herr_t
-H5FD_s3comms_signing_key(
-        unsigned char H5_ATTR_UNUSED *md,
-        const char    H5_ATTR_UNUSED *secret,
-        const char    H5_ATTR_UNUSED *region,
-        const char    H5_ATTR_UNUSED *iso8601now)
-{
-    herr_t ret_value = SUCCEED;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR;
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5FD_s3comms_signing_key() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 
 /*----------------------------------------------------------------------------
  *
@@ -3577,20 +3293,8 @@ H5FD_s3comms_signing_key(
  * Programmer: Jacob Smith
  *             2017-07-??
  *
- * Changes:
- *
- *     - Integrate with HDF5.
- *     - Rename from `tostringtosign` to `H5FD_s3comms_tostringtosign`.
- *     - Return `herr_t` instead of characters written.
- *     - Use HDF-friendly bytes-to-hex function (`H5FD_s3comms_bytes_to_hex`)
- *       instead of general-purpose, deprecated `hex()`.
- *     - Adjust casts to openssl's `SHA256`.
- *     - Input strings are now `const`.
- *     --- Jacob Smith 2017-09-19
- *
  *----------------------------------------------------------------------------
  */
-#ifdef H5_HAVE_ROS3_VFD
 herr_t
 H5FD_s3comms_tostringtosign(
         char       *dest,
@@ -3681,22 +3385,6 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5ros3_tostringtosign() */
 
-#else /* H5_HAVE_ROS3_VFD not defined */
-
-herr_t
-H5FD_s3comms_tostringtosign(
-        char       H5_ATTR_UNUSED *dest,
-        const char H5_ATTR_UNUSED *req,
-        const char H5_ATTR_UNUSED *now,
-        const char H5_ATTR_UNUSED *region)
-{
-    herr_t        ret_value = FAIL;
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5ros3_tostringtosign() */
-
-#endif /* H5_HAVE_ROS3_VFD */
-
 
 /*----------------------------------------------------------------------------
  *
@@ -3725,13 +3413,6 @@ H5FD_s3comms_tostringtosign(
  * Programmer: Jacob Smith
  *             2017-09-18
  *
- * Changes:
- *
- *     - Rename from `trim()` to `H5FD_s3comms_trim()`.
- *     - Incorporate into HDF5.
- *     - Returns `herr_t` type.
- *     --- Jacob Smith 2017-??-??
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -3826,16 +3507,6 @@ done:
  * Programmer: Jacob Smith
  *             2017-07-??
  *
- * Changes:
- *
- *     - Integrate to HDF environment.
- *     - Rename from `uriencode` to `H5FD_s3comms_uriencode`.
- *     - Change return from characters written to herr_t;
- *       move to i/o parameter `n_written`.
- *     - No longer append null-terminator to string;
- *       programmer may append or not as appropriate upon return.
- *     --- Jacob Smith 2017-09-15
- *
  *----------------------------------------------------------------------------
  */
 herr_t
@@ -3915,4 +3586,5 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5FD_s3comms_uriencode */
 
+#endif /* H5_HAVE_ROS3_VFD */
 
diff --git a/src/H5FDs3comms.h b/src/H5FDs3comms.h
index 16f6a8b..94fae7e 100644
--- a/src/H5FDs3comms.h
+++ b/src/H5FDs3comms.h
@@ -52,18 +52,15 @@
  *
  *****************************************************************************/
 
-#include <ctype.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
+#include "H5private.h"      /* Generic Functions        */
 
 #ifdef H5_HAVE_ROS3_VFD
+
+/* Necessary S3 headers */
 #include <curl/curl.h>
 #include <openssl/evp.h>
 #include <openssl/hmac.h>
 #include <openssl/sha.h>
-#endif /* ifdef H5_HAVE_ROS3_VFD */
 
 /*****************
  * PUBLIC MACROS *
@@ -99,9 +96,6 @@
  *     It is left to the programmer to check return value of
  *     ISO8601NOW (should equal ISO8601_SIZE - 1).
  *
- * Programmer: Jacob Smith
- *             2017-07-??
- *
  *---------------------------------------------------------------------------
  */
 #define ISO8601NOW(dest, now_gm) \
@@ -121,9 +115,6 @@ strftime((dest), ISO8601_SIZE, "%Y%m%dT%H%M%SZ", (now_gm))
  *     It is left to the programmer to check return value of
  *     RFC7231NOW (should equal RFC7231_SIZE - 1).
  *
- * Programmer: Jacob Smith
- *             2017-07-??
- *
  *---------------------------------------------------------------------------
  */
 #define RFC7231NOW(dest, now_gm) \
@@ -169,11 +160,6 @@ strftime((dest), RFC7231_SIZE, "%a, %d %b %Y %H:%M:%S GMT", (now_gm))
  *     `region` should be relevant AWS region, i.e. "us-east-1".
  *     `service` should be "s3".
  *
- * Programmer: Jacob Smith
- *             2017-09-19
- *
- * Changes: None.
- *
  *---------------------------------------------------------------------------
  */
 #define S3COMMS_FORMAT_CREDENTIAL(dest, access, iso8601_date, region, service) \
@@ -266,16 +252,6 @@ HDsnprintf((dest), S3COMMS_MAX_CREDENTIAL_SIZE,
  *     Pointers to next node in the list, or NULL sentinel as end of list.
  *     Next node must have a greater `lowername` as determined by strcmp().
  *
- *
- *
- * Programmer: Jacob Smith
- *             2017-09-22
- *
- * Changes:
- *
- *     - Change from twin doubly-linked lists to singly-linked list.
- *     --- Jake Smith 2017-01-17
- *
  *----------------------------------------------------------------------------
  */
 typedef struct hrb_node_t {
@@ -353,10 +329,6 @@ typedef struct hrb_node_t {
  *
  *     Pointer to HTTP version string, e.g., "HTTP/1.1".
  *
- *
- *
- * Programmer: Jacob Smith
- *
  *----------------------------------------------------------------------------
  */
 typedef struct {
@@ -421,10 +393,6 @@ typedef struct {
  *     Single string of all query parameters in url (if any).
  *     "arg1=value1&arg2=value2"
  *
- *
- *
- * Programmer: Jacob Smith
- *
  *----------------------------------------------------------------------------
  */
 typedef struct {
@@ -514,15 +482,10 @@ typedef struct {
  *
  *     Requred to authenticate.
  *
- *
- *
- * Programmer: Jacob Smith
- *
  *----------------------------------------------------------------------------
  */
 typedef struct {
     unsigned long  magic;
-#ifdef H5_HAVE_ROS3_VFD
     CURL          *curlhandle;
     size_t         filesize;
     char          *httpverb;
@@ -530,15 +493,19 @@ typedef struct {
     char          *region;
     char          *secret_id;
     unsigned char *signing_key;
-#endif /* ifdef H5_HAVE_ROS3_VFD */
 } s3r_t;
+
 #define S3COMMS_S3R_MAGIC 0x44d8d79
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*******************************************
  * DECLARATION OF HTTP FIELD LIST ROUTINES *
  *******************************************/
 
-herr_t H5FD_s3comms_hrb_node_set(hrb_node_t **L,
+H5_DLL herr_t H5FD_s3comms_hrb_node_set(hrb_node_t **L,
                                  const char  *name,
                                  const char  *value);
 
@@ -546,9 +513,9 @@ herr_t H5FD_s3comms_hrb_node_set(hrb_node_t **L,
  * DECLARATION OF HTTP REQUEST BUFFER ROUTINES *
  ***********************************************/
 
-herr_t H5FD_s3comms_hrb_destroy(hrb_t **buf);
+H5_DLL herr_t H5FD_s3comms_hrb_destroy(hrb_t **buf);
 
-hrb_t * H5FD_s3comms_hrb_init_request(const char *verb,
+H5_DLL hrb_t * H5FD_s3comms_hrb_init_request(const char *verb,
                                       const char *resource,
                                       const char *host);
 
@@ -576,7 +543,7 @@ H5_DLL herr_t H5FD_s3comms_s3r_read(s3r_t   *handle,
 
 H5_DLL struct tm * gmnow(void);
 
-herr_t H5FD_s3comms_aws_canonical_request(char  *canonical_request_dest,
+H5_DLL herr_t H5FD_s3comms_aws_canonical_request(char  *canonical_request_dest,
                                           int    cr_size,
                                           char  *signed_headers_dest,
                                           int    sh_size,
@@ -587,27 +554,27 @@ H5_DLL herr_t H5FD_s3comms_bytes_to_hex(char                *dest,
                                  size_t               msg_len,
                                  hbool_t              lowercase);
 
-herr_t H5FD_s3comms_free_purl(parsed_url_t *purl);
+H5_DLL herr_t H5FD_s3comms_free_purl(parsed_url_t *purl);
 
-herr_t H5FD_s3comms_HMAC_SHA256(const unsigned char *key,
+H5_DLL herr_t H5FD_s3comms_HMAC_SHA256(const unsigned char *key,
                                 size_t               key_len,
                                 const char          *msg,
                                 size_t               msg_len,
                                 char                *dest);
 
-herr_t H5FD_s3comms_load_aws_profile(const char *name,
+H5_DLL herr_t H5FD_s3comms_load_aws_profile(const char *name,
                                      char       *key_id_out,
                                      char       *secret_access_key_out,
                                      char       *aws_region_out);
 
-herr_t H5FD_s3comms_nlowercase(char       *dest,
+H5_DLL herr_t H5FD_s3comms_nlowercase(char       *dest,
                                const char *s,
                                size_t      len);
 
-herr_t H5FD_s3comms_parse_url(const char    *str,
+H5_DLL herr_t H5FD_s3comms_parse_url(const char    *str,
                               parsed_url_t **purl);
 
-herr_t H5FD_s3comms_percent_encode_char(char                *repr,
+H5_DLL herr_t H5FD_s3comms_percent_encode_char(char                *repr,
                                         const unsigned char  c,
                                         size_t              *repr_len);
 
@@ -616,7 +583,7 @@ H5_DLL herr_t H5FD_s3comms_signing_key(unsigned char *md,
                                        const char    *region,
                                        const char    *iso8601now);
 
-herr_t H5FD_s3comms_tostringtosign(char       *dest,
+H5_DLL herr_t H5FD_s3comms_tostringtosign(char       *dest,
                                    const char *req_str,
                                    const char *now,
                                    const char *region);
@@ -626,10 +593,12 @@ H5_DLL herr_t H5FD_s3comms_trim(char   *dest,
                          size_t  s_len,
                          size_t *n_written);
 
-H5_DLL herr_t H5FD_s3comms_uriencode(char       *dest,
-                              const char *s,
-                              size_t      s_len,
-                              hbool_t     encode_slash,
-                              size_t     *n_written);
+H5_DLL herr_t H5FD_s3comms_uriencode(char *dest, const char *s, size_t s_len,
+    hbool_t encode_slash, size_t *n_written);
+
+#ifdef __cplusplus
+}
+#endif
 
+#endif /* H5_HAVE_ROS3_VFD */
 
diff --git a/src/H5FSsection.c b/src/H5FSsection.c
index 9f86aea..df67bd9 100644
--- a/src/H5FSsection.c
+++ b/src/H5FSsection.c
@@ -390,7 +390,7 @@ HDfprintf(stderr, "%s: fspace->alloc_sect_size = %Hu, fspace->sect_size = %Hu\n"
                 cache_flags |= H5AC__DIRTIED_FLAG;
 
                 /* On file close or flushing, does not allow section info to shrink in size */
-                if(f->closing || flush_in_progress) {
+                if(f->shared->closing || flush_in_progress) {
                     if(fspace->sect_size > fspace->alloc_sect_size)
                         cache_flags |= H5AC__DELETED_FLAG | H5AC__TAKE_OWNERSHIP_FLAG;
                     else
@@ -441,7 +441,7 @@ HDfprintf(stderr, "%s: Relinquishing section info ownership\n", FUNC);
                     /* Set flag to release section info space in file */
                     /* On file close or flushing, only need to release section info with size 
                        bigger than previous section */
-                    if(f->closing || flush_in_progress) {
+                    if(f->shared->closing || flush_in_progress) {
                         if(fspace->sect_size > fspace->alloc_sect_size)
                             release_sinfo_space = TRUE;
                         else
diff --git a/src/H5Faccum.c b/src/H5Faccum.c
index 8d7852b..74a170b 100644
--- a/src/H5Faccum.c
+++ b/src/H5Faccum.c
@@ -111,7 +111,7 @@ H5FL_BLK_DEFINE_STATIC(meta_accum);
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__accum_read(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
+H5F__accum_read(H5F_shared_t *f_sh, H5FD_mem_t map_type, haddr_t addr,
     size_t size, void *buf/*out*/)
 {
     H5FD_t *file;                       /* File driver pointer */
@@ -120,18 +120,18 @@ H5F__accum_read(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
     FUNC_ENTER_PACKAGE
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
     HDassert(buf);
 
     /* Translate to file driver I/O info object */
-    file = f->shared->lf;
+    file = f_sh->lf;
 
     /* Check if this information is in the metadata accumulator */
-    if((f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && map_type != H5FD_MEM_DRAW) {
+    if((f_sh->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && map_type != H5FD_MEM_DRAW) {
         H5F_meta_accum_t *accum;     /* Alias for file's metadata accumulator */
 
         /* Set up alias for file's metadata accumulator info */
-        accum = &f->shared->accum;
+        accum = &f_sh->accum;
 
         if(size < H5F_ACCUM_MAX_SIZE) {
             /* Sanity check */
@@ -419,7 +419,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__accum_write(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
+H5F__accum_write(H5F_shared_t *f_sh, H5FD_mem_t map_type, haddr_t addr,
     size_t size, const void *buf)
 {
     H5FD_t *file;                       /* File driver pointer */
@@ -428,19 +428,19 @@ H5F__accum_write(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
-    HDassert(H5F_INTENT(f) & H5F_ACC_RDWR);
+    HDassert(f_sh);
+    HDassert(H5F_SHARED_INTENT(f_sh) & H5F_ACC_RDWR);
     HDassert(buf);
 
     /* Translate to file driver pointer */
-    file = f->shared->lf;
+    file = f_sh->lf;
 
     /* Check for accumulating metadata */
-    if((f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && map_type != H5FD_MEM_DRAW) {
+    if((f_sh->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && map_type != H5FD_MEM_DRAW) {
         H5F_meta_accum_t *accum;     /* Alias for file's metadata accumulator */
 
         /* Set up alias for file's metadata accumulator info */
-        accum = &f->shared->accum;
+        accum = &f_sh->accum;
 
         if(size < H5F_ACCUM_MAX_SIZE) {
             /* Sanity check */
@@ -732,9 +732,9 @@ H5F__accum_write(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
         } /* end if */
         else {
             /* Make certain that data in accumulator is visible before new write */
-	    if((H5F_INTENT(f) & H5F_ACC_SWMR_WRITE) > 0)
+	    if((H5F_SHARED_INTENT(f_sh) & H5F_ACC_SWMR_WRITE) > 0)
                 /* Flush if dirty and reset accumulator */
-                if(H5F__accum_reset(f, TRUE) < 0)
+                if(H5F__accum_reset(f_sh, TRUE) < 0)
                     HGOTO_ERROR(H5E_IO, H5E_CANTRESET, FAIL, "can't reset accumulator")
 
             /* Write the data */
@@ -783,7 +783,7 @@ H5F__accum_write(H5F_t *f, H5FD_mem_t map_type, haddr_t addr,
                     } /* end if */
                     else {        /* Access covers whole accumulator */
                         /* Reset accumulator, but don't flush */
-                        if(H5F__accum_reset(f, FALSE) < 0)
+                        if(H5F__accum_reset(f_sh, FALSE) < 0)
                             HGOTO_ERROR(H5E_IO, H5E_CANTRESET, FAIL, "can't reset accumulator")
                     } /* end else */
                 } /* end if */
@@ -847,7 +847,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__accum_free(H5F_t *f, H5FD_mem_t H5_ATTR_UNUSED type, haddr_t addr,
+H5F__accum_free(H5F_shared_t *f_sh, H5FD_mem_t H5_ATTR_UNUSED type, haddr_t addr,
     hsize_t size)
 {
     H5F_meta_accum_t *accum;            /* Alias for file's metadata accumulator */
@@ -857,16 +857,16 @@ H5F__accum_free(H5F_t *f, H5FD_mem_t H5_ATTR_UNUSED type, haddr_t addr,
     FUNC_ENTER_PACKAGE
 
     /* check arguments */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Set up alias for file's metadata accumulator info */
-    accum = &f->shared->accum;
+    accum = &f_sh->accum;
 
     /* Translate to file driver pointer */
-    file = f->shared->lf;
+    file = f_sh->lf;
 
     /* Adjust the metadata accumulator to remove the freed block, if it overlaps */
-    if((f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA)
+    if((f_sh->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA)
             && H5F_addr_overlap(addr, size, accum->loc, accum->size)) {
         size_t overlap_size;        /* Size of overlap with accumulator */
 
@@ -1013,28 +1013,28 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__accum_flush(H5F_t *f)
+H5F__accum_flush(H5F_shared_t *f_sh)
 {
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Check if we need to flush out the metadata accumulator */
-    if((f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && f->shared->accum.dirty) {
+    if((f_sh->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) && f_sh->accum.dirty) {
         H5FD_t *file;                       /* File driver pointer */
 
         /* Translate to file driver pointer */
-        file = f->shared->lf;
+        file = f_sh->lf;
 
         /* Flush the metadata contents */
-        if(H5FD_write(file, H5FD_MEM_DEFAULT, f->shared->accum.loc + f->shared->accum.dirty_off, f->shared->accum.dirty_len, f->shared->accum.buf + f->shared->accum.dirty_off) < 0)
+        if(H5FD_write(file, H5FD_MEM_DEFAULT, f_sh->accum.loc + f_sh->accum.dirty_off, f_sh->accum.dirty_len, f_sh->accum.buf + f_sh->accum.dirty_off) < 0)
             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed")
 
         /* Reset the dirty flag */
-        f->shared->accum.dirty = FALSE;
+        f_sh->accum.dirty = FALSE;
     } /* end if */
 
 done:
@@ -1056,34 +1056,31 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__accum_reset(H5F_t *f, hbool_t flush)
+H5F__accum_reset(H5F_shared_t *f_sh, hbool_t flush)
 {
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Flush any dirty data in accumulator, if requested */
     if(flush)
-        if(H5F__accum_flush(f) < 0)
+        if(H5F__accum_flush(f_sh) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "can't flush metadata accumulator")
 
     /* Check if we need to reset the metadata accumulator information */
-    if(f->shared->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) {
-        /* Sanity check */
-        HDassert(!f->closing || FALSE == f->shared->accum.dirty);
-
+    if(f_sh->feature_flags & H5FD_FEAT_ACCUMULATE_METADATA) {
         /* Free the buffer */
-        if(f->shared->accum.buf)
-            f->shared->accum.buf = H5FL_BLK_FREE(meta_accum, f->shared->accum.buf);
+        if(f_sh->accum.buf)
+            f_sh->accum.buf = H5FL_BLK_FREE(meta_accum, f_sh->accum.buf);
 
         /* Reset the buffer sizes & location */
-        f->shared->accum.alloc_size = f->shared->accum.size = 0;
-        f->shared->accum.loc = HADDR_UNDEF;
-        f->shared->accum.dirty = FALSE;
-        f->shared->accum.dirty_len = 0;
+        f_sh->accum.alloc_size = f_sh->accum.size = 0;
+        f_sh->accum.loc = HADDR_UNDEF;
+        f_sh->accum.dirty = FALSE;
+        f_sh->accum.dirty_len = 0;
     } /* end if */
 
 done:
diff --git a/src/H5Fcwfs.c b/src/H5Fcwfs.c
index aa5f8ab..26452b6 100644
--- a/src/H5Fcwfs.c
+++ b/src/H5Fcwfs.c
@@ -299,7 +299,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F_cwfs_remove_heap(H5F_file_t *shared, H5HG_heap_t *heap)
+H5F_cwfs_remove_heap(H5F_shared_t *shared, H5HG_heap_t *heap)
 {
     unsigned u;                         /* Local index variable */
     herr_t ret_value = SUCCEED;         /* Return value */
diff --git a/src/H5Fefc.c b/src/H5Fefc.c
index f3881d4..66d68b2 100644
--- a/src/H5Fefc.c
+++ b/src/H5Fefc.c
@@ -60,14 +60,14 @@ struct H5F_efc_t {
     unsigned            max_nfiles;     /* Maximum size of the external file cache */
     unsigned            nrefs;          /* Number of times this file appears in another file's EFC */
     int                 tag;            /* Temporary variable used by H5F__efc_try_close() */
-    H5F_file_t          *tmp_next;      /* Next file in temporary list used by H5F__efc_try_close() */
+    H5F_shared_t        *tmp_next;      /* Next file in temporary list used by H5F__efc_try_close() */
 };
 
 /* Private prototypes */
 static herr_t H5F__efc_release_real(H5F_efc_t *efc);
 static herr_t H5F__efc_remove_ent(H5F_efc_t *efc, H5F_efc_ent_t *ent);
-static void H5F__efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail);
-static void H5F__efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail);
+static void H5F__efc_try_close_tag1(H5F_shared_t *sf, H5F_shared_t **tail);
+static void H5F__efc_try_close_tag2(H5F_shared_t *sf, H5F_shared_t **tail);
 
 /* Free lists */
 H5FL_DEFINE_STATIC(H5F_efc_ent_t);
@@ -644,10 +644,10 @@ done:
  *-------------------------------------------------------------------------
  */
 static void
-H5F__efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail)
+H5F__efc_try_close_tag1(H5F_shared_t *sf, H5F_shared_t **tail)
 {
     H5F_efc_ent_t       *ent = NULL;    /* EFC entry */
-    H5F_file_t          *esf;           /* Convenience pointer to ent->file->shared */
+    H5F_shared_t          *esf;           /* Convenience pointer to ent->file->shared */
 
     FUNC_ENTER_STATIC_NOERR
 
@@ -718,10 +718,10 @@ H5F__efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail)
  *-------------------------------------------------------------------------
  */
 static void
-H5F__efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail)
+H5F__efc_try_close_tag2(H5F_shared_t *sf, H5F_shared_t **tail)
 {
     H5F_efc_ent_t       *ent = NULL;    /* EFC entry */
-    H5F_file_t          *esf;           /* Convenience pointer to ent->file->shared */
+    H5F_shared_t        *esf;           /* Convenience pointer to ent->file->shared */
 
     FUNC_ENTER_STATIC_NOERR
 
@@ -827,11 +827,11 @@ H5F__efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail)
 herr_t
 H5F__efc_try_close(H5F_t *f)
 {
-    H5F_file_t  *tail;                  /* Tail of linked list of found files.  Head will be f->shared. */
-    H5F_file_t  *uncloseable_head = NULL; /* Head of linked list of files found to be uncloseable by the first pass */
-    H5F_file_t  *uncloseable_tail = NULL; /* Tail of linked list of files found to be uncloseable by the first pass */
-    H5F_file_t  *sf;                    /* Temporary file pointer */
-    H5F_file_t  *next;                  /* Temporary file pointer */
+    H5F_shared_t  *tail;                /* Tail of linked list of found files.  Head will be f->shared. */
+    H5F_shared_t  *uncloseable_head = NULL; /* Head of linked list of files found to be uncloseable by the first pass */
+    H5F_shared_t  *uncloseable_tail = NULL; /* Tail of linked list of files found to be uncloseable by the first pass */
+    H5F_shared_t  *sf;                  /* Temporary file pointer */
+    H5F_shared_t  *next;                /* Temporary file pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_PACKAGE
diff --git a/src/H5Ffake.c b/src/H5Ffake.c
index 6072f2e..67bd180 100644
--- a/src/H5Ffake.c
+++ b/src/H5Ffake.c
@@ -50,7 +50,7 @@ H5F_fake_alloc(uint8_t sizeof_size)
     /* Allocate faked file struct */
     if(NULL == (f = H5FL_CALLOC(H5F_t)))
 	HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, NULL, "can't allocate top file structure")
-    if(NULL == (f->shared = H5FL_CALLOC(H5F_file_t)))
+    if(NULL == (f->shared = H5FL_CALLOC(H5F_shared_t)))
 	HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, NULL, "can't allocate shared file structure")
 
     /* Only set fields necessary for clients */
@@ -93,7 +93,7 @@ H5F_fake_free(H5F_t *f)
     if(f) {
         /* Destroy shared file struct */
         if(f->shared)
-            f->shared = H5FL_FREE(H5F_file_t, f->shared);
+            f->shared = H5FL_FREE(H5F_shared_t, f->shared);
         f = H5FL_FREE(H5F_t, f);
     } /* end if */
 
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 29f017e..5e2cf26 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -58,7 +58,7 @@ typedef struct H5F_olist_t {
     struct {
         hbool_t local;          /* Set flag for "local" file searches */
         union {
-            H5F_file_t *shared; /* Pointer to shared file to look inside */
+            H5F_shared_t *shared; /* Pointer to shared file to look inside */
             const H5F_t *file;  /* Pointer to file to look inside */
         } ptr;
     } file_info;
@@ -81,7 +81,7 @@ static herr_t H5F__get_objects(const H5F_t *f, unsigned types, size_t max_index,
 static int H5F__get_objects_cb(void *obj_ptr, hid_t obj_id, void *key);
 static herr_t H5F__build_name(const char *prefix, const char *file_name, char **full_name/*out*/);
 static char *H5F__getenv_prefix_name(char **env_prefix/*in,out*/);
-static H5F_t *H5F__new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf);
+static H5F_t *H5F__new(H5F_shared_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf);
 static herr_t H5F__build_actual_name(const H5F_t *f, const H5P_genplist_t *fapl, const char *name, char ** /*out*/ actual_name);
 static herr_t H5F__flush_phase1(H5F_t *f);
 static herr_t H5F__flush_phase2(H5F_t *f, hbool_t closing);
@@ -104,8 +104,8 @@ static herr_t H5F__flush_phase2(H5F_t *f, hbool_t closing);
 /* Declare a free list to manage the H5F_t struct */
 H5FL_DEFINE(H5F_t);
 
-/* Declare a free list to manage the H5F_file_t struct */
-H5FL_DEFINE(H5F_file_t);
+/* Declare a free list to manage the H5F_shared_t struct */
+H5FL_DEFINE(H5F_shared_t);
 
 
 
@@ -246,9 +246,9 @@ H5F_get_access_plist(H5F_t *f, hbool_t app_ref)
             HGOTO_ERROR(H5E_FILE, H5E_CANTGET, H5I_INVALID_HID, "can't set minimum raw data fraction of page buffer")
     } /* end if */
 #ifdef H5_HAVE_PARALLEL
-    if(H5P_set(new_plist, H5_COLL_MD_READ_FLAG_NAME, &(f->coll_md_read)) < 0)
+    if(H5P_set(new_plist, H5_COLL_MD_READ_FLAG_NAME, &(f->shared->coll_md_read)) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTGET, H5I_INVALID_HID, "can't set collective metadata read flag")
-    if(H5P_set(new_plist, H5F_ACS_COLL_MD_WRITE_FLAG_NAME, &(f->coll_md_write)) < 0)
+    if(H5P_set(new_plist, H5F_ACS_COLL_MD_WRITE_FLAG_NAME, &(f->shared->coll_md_write)) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTGET, H5I_INVALID_HID, "can't set collective metadata read flag")
 #endif /* H5_HAVE_PARALLEL */
     if(H5P_set(new_plist, H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_NAME, &(f->shared->mdc_initCacheImageCfg)) < 0)
@@ -901,7 +901,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static H5F_t *
-H5F__new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf)
+H5F__new(H5F_shared_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf)
 {
     H5F_t       *f          = NULL;
     H5F_t       *ret_value  = NULL;
@@ -922,7 +922,7 @@ H5F__new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_
         size_t u;                       /* Local index variable */
 
         HDassert(lf != NULL);
-        if(NULL == (f->shared = H5FL_CALLOC(H5F_file_t)))
+        if(NULL == (f->shared = H5FL_CALLOC(H5F_shared_t)))
             HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, NULL, "can't allocate shared file structure")
 
         f->shared->flags = flags;
@@ -1020,9 +1020,9 @@ H5F__new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_
             if(NULL == (f->shared->efc = H5F__efc_create(efc_size)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't create external file cache")
 #ifdef H5_HAVE_PARALLEL
-        if(H5P_get(plist, H5_COLL_MD_READ_FLAG_NAME, &(f->coll_md_read)) < 0)
+        if(H5P_get(plist, H5_COLL_MD_READ_FLAG_NAME, &(f->shared->coll_md_read)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get collective metadata read flag")
-        if(H5P_get(plist, H5F_ACS_COLL_MD_WRITE_FLAG_NAME, &(f->coll_md_write)) < 0)
+        if(H5P_get(plist, H5F_ACS_COLL_MD_WRITE_FLAG_NAME, &(f->shared->coll_md_write)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get collective metadata write flag")
 #endif /* H5_HAVE_PARALLEL */
         if(H5P_get(plist, H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_NAME, &(f->shared->mdc_initCacheImageCfg)) < 0)
@@ -1041,7 +1041,7 @@ H5F__new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_
 
         if(H5FD_get_fs_type_map(lf, f->shared->fs_type_map) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't get free space type mapping from VFD")
-        if(H5MF_init_merge_flags(f) < 0)
+        if(H5MF_init_merge_flags(f->shared) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "problem initializing free space merge flags")
         f->shared->tmp_addr = f->shared->maxaddr;
         /* Disable temp. space allocation for parallel I/O (for now) */
@@ -1141,7 +1141,7 @@ done:
                 if(H5I_dec_ref(f->shared->fcpl_id) < 0)
                     HDONE_ERROR(H5E_FILE, H5E_CANTDEC, NULL, "can't close property list")
 
-            f->shared = H5FL_FREE(H5F_file_t, f->shared);
+            f->shared = H5FL_FREE(H5F_shared_t, f->shared);
         }
         f = H5FL_FREE(H5F_t, f);
     }
@@ -1175,6 +1175,9 @@ H5F__dest(H5F_t *f, hbool_t flush)
     if(1 == f->shared->nrefs) {
         int actype;                         /* metadata cache type (enum value) */
 
+        /* Mark this file as closing */
+        f->shared->closing = TRUE;
+
         /* Flush at this point since the file will be closed (phase 1).
          * Only try to flush the file if it was opened with write access, and if
          * the caller requested a flush.
@@ -1325,7 +1328,7 @@ H5F__dest(H5F_t *f, hbool_t flush)
             HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "problems closing file")
 
         /* Shutdown the page buffer cache */
-        if(H5PB_dest(f) < 0)
+        if(H5PB_dest(f->shared) < 0)
             /* Push error, but keep going*/
             HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "problems closing page buffer cache")
 
@@ -1346,7 +1349,7 @@ H5F__dest(H5F_t *f, hbool_t flush)
         } /* end if */
 
         /* Destroy other components of the file */
-        if(H5F__accum_reset(f, TRUE) < 0)
+        if(H5F__accum_reset(f->shared, TRUE) < 0)
             /* Push error, but keep going*/
             HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "problems closing file")
         if(H5FO_dest(f) < 0)
@@ -1384,13 +1387,16 @@ H5F__dest(H5F_t *f, hbool_t flush)
         f->shared->mtab.child = (H5F_mount_t *)H5MM_xfree(f->shared->mtab.child);
         f->shared->mtab.nalloc = 0;
 
+        /* Free the external link file */
+        f->shared->extpath = (char *)H5MM_xfree(f->shared->extpath);
+
         /* Clean up the metadata retries array */
         for(actype = 0; actype < (int)H5AC_NTYPES; actype++)
             if(f->shared->retries[actype])
                 f->shared->retries[actype] = (uint32_t *)H5MM_xfree(f->shared->retries[actype]);
 
         /* Destroy shared file struct */
-        f->shared = (H5F_file_t *)H5FL_FREE(H5F_file_t, f->shared);
+        f->shared = (H5F_shared_t *)H5FL_FREE(H5F_shared_t, f->shared);
 
     }
     else if(f->shared->nrefs > 0) {
@@ -1404,7 +1410,6 @@ H5F__dest(H5F_t *f, hbool_t flush)
     /* Free the non-shared part of the file */
     f->open_name = (char *)H5MM_xfree(f->open_name);
     f->actual_name = (char *)H5MM_xfree(f->actual_name);
-    f->extpath = (char *)H5MM_xfree(f->extpath);
     if(H5FO_top_dest(f) < 0)
         HDONE_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "problems closing file")
     f->shared = NULL;
@@ -1491,7 +1496,7 @@ H5F_t *
 H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
 {
     H5F_t              *file = NULL;        /*the success return value      */
-    H5F_file_t         *shared = NULL;      /*shared part of `file'         */
+    H5F_shared_t       *shared = NULL;      /*shared part of `file'         */
     H5FD_t             *lf = NULL;          /*file driver part of `shared'  */
     unsigned            tent_flags;         /*tentative flags               */
     H5FD_class_t       *drvr;               /*file driver class info        */
@@ -1650,7 +1655,7 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
     if(page_buf_size) {
 #ifdef H5_HAVE_PARALLEL
         /* Collective metadata writes are not supported with page buffering */
-        if(file->coll_md_write)
+        if(file->shared->coll_md_write)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "collective metadata writes are not supported with page buffering")
 
         /* Temporary: fail file create when page buffering feature is enabled for parallel */
@@ -1675,7 +1680,7 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
 
         /* Create the page buffer before initializing the superblock */
         if(page_buf_size)
-            if(H5PB_create(file, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
+            if(H5PB_create(shared, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to create page buffer")
 
         /* Initialize information about the superblock and allocate space for it */
@@ -1697,7 +1702,7 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
 
         /* Create the page buffer before initializing the superblock */
         if(page_buf_size)
-            if(H5PB_create(file, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
+            if(H5PB_create(shared, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to create page buffer")
 
         /* Open the root group */
@@ -1750,8 +1755,10 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
     } /* end if */
 
     /* Formulate the absolute path for later search of target file for external links */
-    if(H5_build_extpath(name, &file->extpath) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to build extpath")
+    if(shared->nrefs == 1) {
+        if(H5_build_extpath(name, &file->shared->extpath) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to build extpath")
+    }
 
     /* Formulate the actual file name, after following symlinks, etc. */
     if(H5F__build_actual_name(file, a_plist, name, &file->actual_name) < 0)
@@ -1905,12 +1912,12 @@ H5F__flush_phase2(H5F_t *f, hbool_t closing)
 #endif /* H5_HAVE_PARALLEL */
 
     /* Flush out the metadata accumulator */
-    if(H5F__accum_flush(f) < 0)
+    if(H5F__accum_flush(f->shared) < 0)
         /* Push error, but keep going*/
         HDONE_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush metadata accumulator")
 
     /* Flush the page buffer */
-    if(H5PB_flush(f) < 0)
+    if(H5PB_flush(f->shared) < 0)
         /* Push error, but keep going*/
         HDONE_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "page buffer flush failed")
 
@@ -2181,7 +2188,7 @@ H5F_try_close(H5F_t *f, hbool_t *was_closed /*out*/)
      */
 
     /* Destroy the H5F_t struct and decrement the reference count for the
-     * shared H5F_file_t struct. If the reference count for the H5F_file_t
+     * shared H5F_shared_t struct. If the reference count for the H5F_shared_t
      * struct reaches zero then destroy it also.
      */
     if(H5F__dest(f, TRUE) < 0)
@@ -2224,7 +2231,6 @@ H5F__reopen(H5F_t *f)
     /* Duplicate old file's names */
     ret_value->open_name    = H5MM_xstrdup(f->open_name);
     ret_value->actual_name  = H5MM_xstrdup(f->actual_name);
-    ret_value->extpath      = H5MM_xstrdup(f->extpath);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -3152,31 +3158,6 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__get_max_eof_eoa() */
 
-#ifdef H5_HAVE_PARALLEL
-
-/*-------------------------------------------------------------------------
- * Function:    H5F_set_coll_md_read
- *
- * Purpose:     Set the coll_md_read field with a new value.
- *
- * Return:      SUCCEED/FAIL
- *-------------------------------------------------------------------------
- */
-void
-H5F_set_coll_md_read(H5F_t *f, H5P_coll_md_read_flag_t cmr)
-{
-    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /* Sanity check */
-    HDassert(f);
-
-    f->coll_md_read = cmr;
-
-    FUNC_LEAVE_NOAPI_VOID
-} /* H5F_set_coll_md_read() */
-#endif /* H5_HAVE_PARALLEL */
-
 
 /*-------------------------------------------------------------------------
  * Function:    H5F_get_metadata_read_retry_info
@@ -3416,7 +3397,7 @@ H5F__start_swmr_write(H5F_t *f)
     } /* end if */
 
     /* Flush and reset the accumulator */
-    if(H5F__accum_reset(f, TRUE) < 0)
+    if(H5F__accum_reset(f->shared, TRUE) < 0)
         HGOTO_ERROR(H5E_IO, H5E_CANTRESET, FAIL, "can't reset accumulator")
 
     /* Turn on SWMR write in shared file open flags */
diff --git a/src/H5Fio.c b/src/H5Fio.c
index 69e6bb2..34dd0d6 100644
--- a/src/H5Fio.c
+++ b/src/H5Fio.c
@@ -77,6 +77,50 @@
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5F_shared_block_read
+ *
+ * Purpose:	Reads some data from a file/server/etc into a buffer.
+ *		The data is contiguous.	 The address is relative to the base
+ *		address for the file.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Robb Matzke
+ *		matzke@llnl.gov
+ *		Jul 10 1997
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_shared_block_read(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/)
+{
+    H5FD_mem_t  map_type;               /* Mapped memory type */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f_sh);
+    HDassert(buf);
+    HDassert(H5F_addr_defined(addr));
+
+    /* Check for attempting I/O on 'temporary' file address */
+    if(H5F_addr_le(f_sh->tmp_addr, (addr + size)))
+        HGOTO_ERROR(H5E_IO, H5E_BADRANGE, FAIL, "attempting I/O in temporary file space")
+
+    /* Treat global heap as raw data */
+    map_type = (type == H5FD_MEM_GHEAP) ? H5FD_MEM_DRAW : type;
+
+    /* Pass through page buffer layer */
+    if(H5PB_read(f_sh, map_type, addr, size, buf) < 0)
+        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "read through page buffer failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_shared_block_read() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5F_block_read
  *
  * Purpose:	Reads some data from a file/server/etc into a buffer.
@@ -113,7 +157,7 @@ H5F_block_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*
     map_type = (type == H5FD_MEM_GHEAP) ? H5FD_MEM_DRAW : type;
 
     /* Pass through page buffer layer */
-    if(H5PB_read(f, map_type, addr, size, buf) < 0)
+    if(H5PB_read(f->shared, map_type, addr, size, buf) < 0)
         HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "read through page buffer failed")
 
 done:
@@ -122,6 +166,51 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5F_shared_block_write
+ *
+ * Purpose:	Writes some data from memory to a file/server/etc.  The
+ *		data is contiguous.  The address is relative to the base
+ *		address.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Robb Matzke
+ *		matzke@llnl.gov
+ *		Jul 10 1997
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_shared_block_write(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf)
+{
+    H5FD_mem_t  map_type;               /* Mapped memory type */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f_sh);
+    HDassert(H5F_SHARED_INTENT(f_sh) & H5F_ACC_RDWR);
+    HDassert(buf);
+    HDassert(H5F_addr_defined(addr));
+
+    /* Check for attempting I/O on 'temporary' file address */
+    if(H5F_addr_le(f_sh->tmp_addr, (addr + size)))
+        HGOTO_ERROR(H5E_IO, H5E_BADRANGE, FAIL, "attempting I/O in temporary file space")
+
+    /* Treat global heap as raw data */
+    map_type = (type == H5FD_MEM_GHEAP) ? H5FD_MEM_DRAW : type;
+
+    /* Pass through page buffer layer */
+    if(H5PB_write(f_sh, map_type, addr, size, buf) < 0)
+        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write through page buffer failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_shared_block_write() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5F_block_write
  *
  * Purpose:	Writes some data from memory to a file/server/etc.  The
@@ -159,7 +248,7 @@ H5F_block_write(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, const void
     map_type = (type == H5FD_MEM_GHEAP) ? H5FD_MEM_DRAW : type;
 
     /* Pass through page buffer layer */
-    if(H5PB_write(f, map_type, addr, size, buf) < 0)
+    if(H5PB_write(f->shared, map_type, addr, size, buf) < 0)
         HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write through page buffer failed")
 
 done:
@@ -170,7 +259,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function:    H5F_flush_tagged_metadata
  *
- * Purpose:     Flushes metadata with specified tag in the metadata cache 
+ * Purpose:     Flushes metadata with specified tag in the metadata cache
  *              to disk.
  *
  * Return:      Non-negative on success/Negative on failure
@@ -192,7 +281,7 @@ H5F_flush_tagged_metadata(H5F_t *f, haddr_t tag)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to flush tagged metadata")
 
     /* Flush and reset the accumulator */
-    if(H5F__accum_reset(f, TRUE) < 0)
+    if(H5F__accum_reset(f->shared, TRUE) < 0)
         HGOTO_ERROR(H5E_IO, H5E_CANTRESET, FAIL, "can't reset accumulator")
 
     /* Flush file buffers to disk. */
diff --git a/src/H5Fmpi.c b/src/H5Fmpi.c
index 12bcbc0..bb422ac 100644
--- a/src/H5Fmpi.c
+++ b/src/H5Fmpi.c
@@ -130,7 +130,7 @@ H5F_mpi_get_rank(const H5F_t *f)
 
     /* Dispatch to driver */
     if ((ret_value = H5FD_mpi_get_rank(f->shared->lf)) < 0)
-        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, (-1), "driver get_rank request failed")
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, (-1), "driver get_rank request failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -162,7 +162,7 @@ H5F_mpi_get_comm(const H5F_t *f)
 
     /* Dispatch to driver */
     if ((ret_value = H5FD_mpi_get_comm(f->shared->lf)) == MPI_COMM_NULL)
-        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, MPI_COMM_NULL, "driver get_comm request failed")
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, MPI_COMM_NULL, "driver get_comm request failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -170,6 +170,38 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5F_shared_mpi_get_size
+ *
+ * Purpose:     Retrieves the size of an MPI process.
+ *
+ * Return:      Success:        The size (positive)
+ *
+ *              Failure:        Negative
+ *
+ * Programmer:  John Mainzer
+ *              Friday, May 6, 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5F_shared_mpi_get_size(const H5F_shared_t *f_sh)
+{
+    int ret_value = -1;
+
+    FUNC_ENTER_NOAPI((-1))
+
+    HDassert(f_sh);
+
+    /* Dispatch to driver */
+    if((ret_value = H5FD_mpi_get_size(f_sh->lf)) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, (-1), "driver get_size request failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_shared_mpi_get_size() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5F_mpi_get_size
  *
  * Purpose:     Retrieves the size of an MPI process.
@@ -194,7 +226,7 @@ H5F_mpi_get_size(const H5F_t *f)
 
     /* Dispatch to driver */
     if ((ret_value = H5FD_mpi_get_size(f->shared->lf)) < 0)
-        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, (-1), "driver get_size request failed")
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, (-1), "driver get_size request failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -336,14 +368,9 @@ H5F_mpi_retrieve_comm(hid_t loc_id, hid_t acspl_id, MPI_Comm *mpi_comm)
         if(NULL == (plist = H5P_object_verify(acspl_id, H5P_FILE_ACCESS)))
             HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "not a file access list")
 
-        if(H5FD_MPIO == H5P_peek_driver(plist)) {
-            const H5FD_mpio_fapl_t *fa; /* MPIO fapl info */
-
-            if(NULL == (fa = (const H5FD_mpio_fapl_t *)H5P_peek_driver_info(plist)))
-                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad VFL driver info")
-
-            *mpi_comm = fa->comm;
-        }
+        if(H5FD_MPIO == H5P_peek_driver(plist))
+            if(H5P_peek(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, mpi_comm) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get MPI communicator")
     }
 
 done:
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index dbf68c3..6cd2d3c 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -217,7 +217,7 @@ typedef struct H5F_mtab_t {
 } H5F_mtab_t;
 
 /* Structure specifically to store superblock. This was originally
- * maintained entirely within H5F_file_t, but is now extracted
+ * maintained entirely within H5F_shared_t, but is now extracted
  * here because the superblock is now handled by the cache */
 typedef struct H5F_super_t {
     H5AC_info_t cache_info;     /* Cache entry information structure          */
@@ -238,11 +238,11 @@ typedef struct H5F_super_t {
 /*
  * Define the structure to store the file information for HDF5 files. One of
  * these structures is allocated per file, not per H5Fopen(). That is, set of
- * H5F_t structs can all point to the same H5F_file_t struct. The `nrefs'
+ * H5F_t structs can all point to the same H5F_shared_t struct. The `nrefs'
  * count in this struct indicates the number of H5F_t structs which are
  * pointing to this struct.
  */
-struct H5F_file_t {
+struct H5F_shared_t {
     H5FD_t	*lf; 		/* Lower level file handle for I/O	*/
     H5F_super_t *sblock;        /* Pointer to (pinned) superblock for file */
     H5O_drvinfo_t *drvinfo;	/* Pointer to the (pinned) driver info 
@@ -309,6 +309,7 @@ struct H5F_file_t {
     struct H5G_t *root_grp;	/* Open root group			*/
     H5FO_t *open_objs;          /* Open objects in file                 */
     H5UC_t *grp_btree_shared;   /* Ref-counted group B-tree node info   */
+    hbool_t     closing;        /* File is in the process of being closed */
 
     /* Cached VOL connector ID & info */
     hid_t       vol_id;         /* ID of VOL connector for the container */
@@ -357,28 +358,31 @@ struct H5F_file_t {
     /* Object flush info */
     H5F_object_flush_t 	object_flush;	    /* Information for object flush callback */
     hbool_t crt_dset_min_ohdr_flag; /* flag to minimize created dataset object header */
+
+    char               *extpath;        /* Path for searching target external link file                 */
+
+#ifdef H5_HAVE_PARALLEL
+    H5P_coll_md_read_flag_t coll_md_read;  /* Do all metadata reads collectively */
+    hbool_t             coll_md_write;  /* Do all metadata writes collectively */
+#endif /* H5_HAVE_PARALLEL */
+
 };
 
 /*
  * This is the top-level file descriptor.  One of these structures is
  * allocated every time H5Fopen() is called although they may contain pointers
- * to shared H5F_file_t structs.
+ * to shared H5F_shared_t structs.
  */
 struct H5F_t {
-    char		       *open_name;      /* Name used to open file                                       */
-    char		       *actual_name;    /* Actual name of the file, after resolving symlinks, etc.      */
-    char               *extpath;        /* Path for searching target external link file                 */
-    H5F_file_t		   *shared;         /* The shared file info                                         */
-    unsigned		    nopen_objs;     /* Number of open object headers                                */
+    char	       *open_name;      /* Name used to open file                                       */
+    char	       *actual_name;    /* Actual name of the file, after resolving symlinks, etc.      */
+    H5F_shared_t       *shared;         /* The shared file info                                         */
+    unsigned	        nopen_objs;     /* Number of open object headers                                */
     H5FO_t             *obj_count;      /* # of time each object is opened through top file structure   */
     hbool_t             id_exists;      /* Whether an ID for this struct exists                         */
     hbool_t             closing;        /* File is in the process of being closed                       */
     struct H5F_t       *parent;         /* Parent file that this file is mounted to                     */
     unsigned            nmounts;        /* Number of children mounted to this file                      */
-#ifdef H5_HAVE_PARALLEL
-    H5P_coll_md_read_flag_t coll_md_read;  /* Do all metadata reads collectively */
-    hbool_t             coll_md_write;  /* Do all metadata writes collectively */
-#endif /* H5_HAVE_PARALLEL */
 };
 
 /*****************************/
@@ -388,8 +392,8 @@ struct H5F_t {
 /* Declare a free list to manage the H5F_t struct */
 H5FL_EXTERN(H5F_t);
 
-/* Declare a free list to manage the H5F_file_t struct */
-H5FL_EXTERN(H5F_file_t);
+/* Declare a free list to manage the H5F_shared_t struct */
+H5FL_EXTERN(H5F_shared_t);
 
 
 /******************************/
@@ -429,16 +433,16 @@ H5_DLL herr_t H5F__super_ext_remove_msg(H5F_t *f, unsigned id);
 H5_DLL herr_t H5F__super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr, hbool_t was_created);
 
 /* Metadata accumulator routines */
-H5_DLL herr_t H5F__accum_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf);
-H5_DLL herr_t H5F__accum_write(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
-H5_DLL herr_t H5F__accum_free(H5F_t *f, H5FD_mem_t type, haddr_t addr, hsize_t size);
-H5_DLL herr_t H5F__accum_flush(H5F_t *f);
-H5_DLL herr_t H5F__accum_reset(H5F_t *f, hbool_t flush);
+H5_DLL herr_t H5F__accum_read(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, void *buf);
+H5_DLL herr_t H5F__accum_write(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
+H5_DLL herr_t H5F__accum_free(H5F_shared_t *f, H5FD_mem_t type, haddr_t addr, hsize_t size);
+H5_DLL herr_t H5F__accum_flush(H5F_shared_t *f_sh);
+H5_DLL herr_t H5F__accum_reset(H5F_shared_t *f_sh, hbool_t flush);
 
 /* Shared file list related routines */
-H5_DLL herr_t H5F__sfile_add(H5F_file_t *shared);
-H5_DLL H5F_file_t *H5F__sfile_search(H5FD_t *lf);
-H5_DLL herr_t H5F__sfile_remove(H5F_file_t *shared);
+H5_DLL herr_t H5F__sfile_add(H5F_shared_t *shared);
+H5_DLL H5F_shared_t *H5F__sfile_search(H5FD_t *lf);
+H5_DLL herr_t H5F__sfile_remove(H5F_shared_t *shared);
 
 /* External file cache routines */
 H5_DLL H5F_efc_t *H5F__efc_create(unsigned max_nfiles);
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 838fa28..8c70663 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -278,10 +278,11 @@ typedef struct H5F_t H5F_t;
 #ifdef H5F_MODULE
 #define H5F_LOW_BOUND(F)        ((F)->shared->low_bound)
 #define H5F_HIGH_BOUND(F)       ((F)->shared->high_bound)
+#define H5F_SHARED_INTENT(F_SH) ((F_SH)->flags)
 #define H5F_INTENT(F)           ((F)->shared->flags)
 #define H5F_OPEN_NAME(F)        ((F)->open_name)
 #define H5F_ACTUAL_NAME(F)      ((F)->actual_name)
-#define H5F_EXTPATH(F)          ((F)->extpath)
+#define H5F_EXTPATH(F)          ((F)->shared->extpath)
 #define H5F_SHARED(F)           ((F)->shared)
 #define H5F_SAME_SHARED(F1, F2) ((F1)->shared == (F2)->shared)
 #define H5F_NOPEN_OBJS(F)       ((F)->nopen_objs)
@@ -293,6 +294,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_GET_READ_ATTEMPTS(F) ((F)->shared->read_attempts)
 #define H5F_DRIVER_ID(F)        ((F)->shared->lf->driver_id)
 #define H5F_GET_FILENO(F,FILENUM) ((FILENUM) = (F)->shared->lf->fileno)
+#define H5F_SHARED_HAS_FEATURE(F_SH,FL) ((F_SH)->lf->feature_flags & (FL))
 #define H5F_HAS_FEATURE(F,FL)   ((F)->shared->lf->feature_flags & (FL))
 #define H5F_BASE_ADDR(F)        ((F)->shared->sblock->base_addr)
 #define H5F_SYM_LEAF_K(F)       ((F)->shared->sblock->sym_leaf_k)
@@ -321,7 +323,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_USE_TMP_SPACE(F)    ((F)->shared->fs.use_tmp_space)
 #define H5F_IS_TMP_ADDR(F, ADDR) (H5F_addr_le((F)->shared->fs.tmp_addr, (ADDR)))
 #ifdef H5_HAVE_PARALLEL
-#define H5F_COLL_MD_READ(F)     ((F)->coll_md_read)
+#define H5F_COLL_MD_READ(F)     ((F)->shared->coll_md_read)
 #endif /* H5_HAVE_PARALLEL */
 #define H5F_USE_MDC_LOGGING(F)  ((F)->shared->use_mdc_logging)
 #define H5F_START_MDC_LOG_ON_ACCESS(F)  ((F)->shared->start_mdc_log_on_access)
@@ -336,6 +338,7 @@ typedef struct H5F_t H5F_t;
 #else /* H5F_MODULE */
 #define H5F_LOW_BOUND(F)        (H5F_get_low_bound(F))
 #define H5F_HIGH_BOUND(F)       (H5F_get_high_bound(F))
+#define H5F_SHARED_INTENT(F_SH) (H5F_shared_get_intent(F_SH))
 #define H5F_INTENT(F)           (H5F_get_intent(F))
 #define H5F_OPEN_NAME(F)        (H5F_get_open_name(F))
 #define H5F_ACTUAL_NAME(F)      (H5F_get_actual_name(F))
@@ -351,6 +354,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_GET_READ_ATTEMPTS(F) (H5F_get_read_attempts(F))
 #define H5F_DRIVER_ID(F)        (H5F_get_driver_id(F))
 #define H5F_GET_FILENO(F,FILENUM) (H5F_get_fileno((F), &(FILENUM)))
+#define H5F_SHARED_HAS_FEATURE(F_SH,FL) (H5F_shared_has_feature(F_SH,FL))
 #define H5F_HAS_FEATURE(F,FL)   (H5F_has_feature(F,FL))
 #define H5F_BASE_ADDR(F)        (H5F_get_base_addr(F))
 #define H5F_SYM_LEAF_K(F)       (H5F_sym_leaf_k(F))
@@ -509,6 +513,10 @@ typedef struct H5F_t H5F_t;
 #define H5F_ACS_PAGE_BUFFER_SIZE_NAME           "page_buffer_size" /* the maximum size for the page buffer cache */
 #define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME  "page_buffer_min_meta_perc" /* the min metadata percentage for the page buffer cache */
 #define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME   "page_buffer_min_raw_perc" /* the min raw data percentage for the page buffer cache */
+#ifdef H5_HAVE_PARALLEL
+#define H5F_ACS_MPI_PARAMS_COMM_NAME            "mpi_params_comm" /* the MPI communicator */
+#define H5F_ACS_MPI_PARAMS_INFO_NAME            "mpi_params_info" /* the MPI info struct */
+#endif /* H5_HAVE_PARALLEL */
 
 /* ======================== File Mount properties ====================*/
 #define H5F_MNT_SYM_LOCAL_NAME         "local"                 /* Whether absolute symlinks local to file. */
@@ -575,6 +583,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_SDATA_BLOCK_SIZE_DEF    2048
 
 /* Check for file using paged aggregation */
+#define H5F_SHARED_PAGED_AGGR(F_SH) ((F_SH)->fs_strategy == H5F_FSPACE_STRATEGY_PAGE && (F_SH)->fs_page_size)
 #define H5F_PAGED_AGGR(F) (F->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE && F->shared->fs_page_size)
 
 /* Metadata read attempt values */
@@ -651,7 +660,7 @@ struct H5P_genplist_t;
 /* Forward declarations for anonymous H5F objects */
 
 /* Main file structures */
-typedef struct H5F_file_t H5F_file_t;
+typedef struct H5F_shared_t H5F_shared_t;
 
 /* Block aggregation structure */
 typedef struct H5F_blk_aggr_t H5F_blk_aggr_t;
@@ -723,11 +732,12 @@ H5_DLL hid_t H5F_get_file_id(hid_t obj_id, H5I_type_t id_type, hbool_t app_ref);
 /* Functions that retrieve values from the file struct */
 H5_DLL H5F_libver_t H5F_get_low_bound(const H5F_t *f);
 H5_DLL H5F_libver_t H5F_get_high_bound(const H5F_t *f);
+H5_DLL unsigned H5F_shared_get_intent(const H5F_shared_t *f);
 H5_DLL unsigned H5F_get_intent(const H5F_t *f);
 H5_DLL char *H5F_get_open_name(const H5F_t *f);
 H5_DLL char *H5F_get_actual_name(const H5F_t *f);
 H5_DLL char *H5F_get_extpath(const H5F_t *f);
-H5_DLL H5F_file_t *H5F_get_shared(const H5F_t *f);
+H5_DLL H5F_shared_t *H5F_get_shared(const H5F_t *f);
 H5_DLL hbool_t H5F_same_shared(const H5F_t *f1, const H5F_t *f2);
 H5_DLL unsigned H5F_get_nopen_objs(const H5F_t *f);
 H5_DLL unsigned H5F_incr_nopen_objs(H5F_t *f);
@@ -786,7 +796,9 @@ H5_DLL char *H5F_mdc_log_location(const H5F_t *f);
 /* Functions that retrieve values from VFD layer */
 H5_DLL hid_t H5F_get_driver_id(const H5F_t *f);
 H5_DLL herr_t H5F_get_fileno(const H5F_t *f, unsigned long *filenum);
+H5_DLL hbool_t H5F_shared_has_feature(const H5F_shared_t *f, unsigned feature);
 H5_DLL hbool_t H5F_has_feature(const H5F_t *f, unsigned feature);
+H5_DLL haddr_t H5F_shared_get_eoa(const H5F_shared_t *f_sh, H5FD_mem_t type);
 H5_DLL haddr_t H5F_get_eoa(const H5F_t *f, H5FD_mem_t type);
 H5_DLL herr_t H5F_get_vfd_handle(const H5F_t *file, hid_t fapl, void **file_handle);
 
@@ -797,7 +809,9 @@ H5_DLL herr_t H5F_traverse_mount(struct H5O_loc_t *oloc/*in,out*/);
 H5_DLL herr_t H5F_flush_mounts(H5F_t *f);
 
 /* Functions that operate on blocks of bytes wrt super block */
+H5_DLL herr_t H5F_shared_block_read(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/);
 H5_DLL herr_t H5F_block_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/);
+H5_DLL herr_t H5F_shared_block_write(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
 H5_DLL herr_t H5F_block_write(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
 
 /* Functions that flush or evict */
@@ -837,6 +851,7 @@ H5_DLL herr_t H5F_eoa_dirty(H5F_t *f);
 H5_DLL herr_t H5F_get_mpi_handle(const H5F_t *f, MPI_File **f_handle);
 H5_DLL int H5F_mpi_get_rank(const H5F_t *f);
 H5_DLL MPI_Comm H5F_mpi_get_comm(const H5F_t *f);
+H5_DLL int H5F_shared_mpi_get_size(const H5F_shared_t *f_sh);
 H5_DLL int H5F_mpi_get_size(const H5F_t *f);
 H5_DLL herr_t H5F_mpi_retrieve_comm(hid_t loc_id, hid_t acspl_id, MPI_Comm *mpi_comm);
 H5_DLL herr_t H5F_get_mpi_info(const H5F_t *f, MPI_Info **f_info);
@@ -853,7 +868,7 @@ H5_DLL H5F_t *H5F_prefix_open_file(H5F_t *primary_file, H5F_prefix_open_t prefix
 H5_DLL herr_t H5F_cwfs_add(H5F_t *f, struct H5HG_heap_t *heap);
 H5_DLL herr_t H5F_cwfs_find_free_heap(H5F_t *f, size_t need, haddr_t *addr);
 H5_DLL herr_t H5F_cwfs_advance_heap(H5F_t *f, struct H5HG_heap_t *heap, hbool_t add_heap);
-H5_DLL herr_t H5F_cwfs_remove_heap(H5F_file_t *shared, struct H5HG_heap_t *heap);
+H5_DLL herr_t H5F_cwfs_remove_heap(H5F_shared_t *shared, struct H5HG_heap_t *heap);
 
 /* Debugging functions */
 H5_DLL herr_t H5F_debug(H5F_t *f, FILE * stream, int indent, int fwidth);
diff --git a/src/H5Fquery.c b/src/H5Fquery.c
index c168535..f36f348 100644
--- a/src/H5Fquery.c
+++ b/src/H5Fquery.c
@@ -75,6 +75,28 @@
 
 
 /*-------------------------------------------------------------------------
+ * Function: H5F_shared_get_intent
+ *
+ * Purpose:  Quick and dirty routine to retrieve the file's 'intent' flags
+ *           (Mainly added to stop non-file routines from poking about in the
+ *           H5F_shared_t data structure)
+ *
+ * Return:   'intent' on success/abort on failure (shouldn't fail)
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_shared_get_intent(const H5F_shared_t *f_sh)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f_sh);
+
+    FUNC_LEAVE_NOAPI(f_sh->flags)
+} /* end H5F_shared_get_intent() */
+
+
+/*-------------------------------------------------------------------------
  * Function: H5F_get_intent
  *
  * Purpose:  Quick and dirty routine to retrieve the file's 'intent' flags
@@ -207,9 +229,9 @@ H5F_get_extpath(const H5F_t *f)
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     HDassert(f);
-    HDassert(f->extpath);
+    HDassert(f->shared->extpath);
 
-    FUNC_LEAVE_NOAPI(f->extpath)
+    FUNC_LEAVE_NOAPI(f->shared->extpath)
 } /* end H5F_get_extpath() */
 
 
@@ -221,7 +243,7 @@ H5F_get_extpath(const H5F_t *f)
  * Return:   'shared' on success/abort on failure (shouldn't fail)
  *-------------------------------------------------------------------------
  */
-H5F_file_t *
+H5F_shared_t *
 H5F_get_shared(const H5F_t *f)
 {
     /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
@@ -827,6 +849,27 @@ H5F_store_msg_crt_idx(const H5F_t *f)
 
 
 /*-------------------------------------------------------------------------
+ * Function: H5F_shared_has_feature
+ *
+ * Purpose:  Check if a file has a particular feature enabled
+ *
+ * Return:   Success:    Non-negative - TRUE or FALSE
+ *           Failure:    Negative (should not happen)
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5F_shared_has_feature(const H5F_shared_t *f_sh, unsigned feature)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f_sh);
+
+    FUNC_LEAVE_NOAPI((hbool_t)(f_sh->lf->feature_flags & feature))
+} /* end H5F_shared_has_feature() */
+
+
+/*-------------------------------------------------------------------------
  * Function: H5F_has_feature
  *
  * Purpose:  Check if a file has a particular feature enabled
@@ -904,6 +947,32 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function: H5F_shared_get_eoa
+ *
+ * Purpose:  Quick and dirty routine to retrieve the file's 'eoa' value
+ *
+ * Return:   Non-negative on success/Negative on failure
+ *-------------------------------------------------------------------------
+ */
+haddr_t
+H5F_shared_get_eoa(const H5F_shared_t *f_sh, H5FD_mem_t type)
+{
+    haddr_t    ret_value = HADDR_UNDEF;        /* Return value */
+
+    FUNC_ENTER_NOAPI(HADDR_UNDEF)
+
+    HDassert(f_sh);
+
+    /* Dispatch to driver */
+    if(HADDR_UNDEF == (ret_value = H5FD_get_eoa(f_sh->lf, type)))
+        HGOTO_ERROR(H5E_VFL, H5E_CANTINIT, HADDR_UNDEF, "driver get_eoa request failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_shared_get_eoa() */
+
+
+/*-------------------------------------------------------------------------
  * Function: H5F_get_eoa
  *
  * Purpose:  Quick and dirty routine to retrieve the file's 'eoa' value
@@ -1026,7 +1095,7 @@ H5F_coll_md_read(const H5F_t *f)
 
     HDassert(f);
 
-    FUNC_LEAVE_NOAPI(f->coll_md_read)
+    FUNC_LEAVE_NOAPI(f->shared->coll_md_read)
 } /* end H5F_coll_md_read() */
 #endif /* H5_HAVE_PARALLEL */
 
diff --git a/src/H5Fsfile.c b/src/H5Fsfile.c
index ebc2ab2..9a9bbab 100644
--- a/src/H5Fsfile.c
+++ b/src/H5Fsfile.c
@@ -24,7 +24,7 @@
 
 /* Struct for tracking "shared" file structs */
 typedef struct H5F_sfile_node_t {
-    H5F_file_t *shared;                 /* Pointer to "shared" file struct */
+    H5F_shared_t *shared;               /* Pointer to "shared" file struct */
     struct H5F_sfile_node_t *next;      /* Pointer to next node */
 } H5F_sfile_node_t;
 
@@ -96,9 +96,9 @@ H5F_sfile_assert_num(unsigned n)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__sfile_add(H5F_file_t *shared)
+H5F__sfile_add(H5F_shared_t *shared)
 {
-    H5F_sfile_node_t *new_shared;              /* New shared file node */
+    H5F_sfile_node_t *new_shared;       /* New shared file node */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_PACKAGE
@@ -135,11 +135,11 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-H5F_file_t *
+H5F_shared_t *
 H5F__sfile_search(H5FD_t *lf)
 {
     H5F_sfile_node_t *curr;             /* Current shared file node */
-    H5F_file_t *ret_value = NULL;       /* Return value */
+    H5F_shared_t *ret_value = NULL;     /* Return value */
 
     FUNC_ENTER_PACKAGE_NOERR
 
@@ -175,7 +175,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5F__sfile_remove(H5F_file_t *shared)
+H5F__sfile_remove(H5F_shared_t *shared)
 {
     H5F_sfile_node_t *curr;             /* Current shared file node */
     H5F_sfile_node_t *last;             /* Last shared file node */
diff --git a/src/H5HGpkg.h b/src/H5HGpkg.h
index 4ed9b10..3119de4 100644
--- a/src/H5HGpkg.h
+++ b/src/H5HGpkg.h
@@ -117,7 +117,7 @@ typedef struct H5HG_obj_t {
 } H5HG_obj_t;
 
 /* Forward declarations for fields */
-struct H5F_file_t;
+struct H5F_shared_t;
 
 struct H5HG_heap_t {
     H5AC_info_t cache_info; /* Information for H5AC cache functions, _must_ be */
@@ -130,7 +130,7 @@ struct H5HG_heap_t {
                                         /* If this value is >65535 then all indices */
                                         /* have been used at some time and the */
                                         /* correct new index should be searched for */
-    struct H5F_file_t   *shared;        /* shared file */
+    struct H5F_shared_t   *shared;      /* shared file */
     H5HG_obj_t	*obj;		/*array of object descriptions	*/
 };
 
diff --git a/src/H5MF.c b/src/H5MF.c
index 3d9ddb0..14be37a 100644
--- a/src/H5MF.c
+++ b/src/H5MF.c
@@ -55,6 +55,11 @@
     if(!H5F_addr_defined(FSM->addr) || !H5F_addr_defined(FSM->sect_addr))   \
         *CF = TRUE;
 
+/* For non-paged aggregation: map allocation request type to tracked free-space type */
+/* F_SH -- pointer to H5F_shared_t; T -- H5FD_mem_t */
+#define H5MF_ALLOC_TO_FS_AGGR_TYPE(F_SH, T)                  \
+        ((H5FD_MEM_DEFAULT == (F_SH)->fs_type_map[T]) ? (T) : (F_SH)->fs_type_map[T])
+
 /******************/
 /* Local Typedefs */
 /******************/
@@ -93,9 +98,9 @@ static herr_t H5MF__close_shrink_eoa(H5F_t *f);
 
 /* General routines */
 static herr_t H5MF__get_free_sects(H5F_t *f, H5FS_t *fspace, H5MF_sect_iter_ud_t *sect_udata, size_t *nums);
-static hbool_t H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type);
-static hbool_t H5MF__fsm_is_self_referential(H5F_t *f, H5FS_t *fspace);
-static herr_t H5MF__continue_alloc_fsm(H5F_t *f, H5FS_t *sm_hdr_fspace, H5FS_t *sm_sinfo_fspace, 
+static hbool_t H5MF__fsm_type_is_self_referential(H5F_shared_t *f_sh, H5F_mem_page_t fsm_type);
+static hbool_t H5MF__fsm_is_self_referential(H5F_shared_t *f_sh, H5FS_t *fspace);
+static herr_t H5MF__continue_alloc_fsm(H5F_shared_t *f_sh, H5FS_t *sm_hdr_fspace, H5FS_t *sm_sinfo_fspace, 
     H5FS_t  *lg_hdr_fspace, H5FS_t *lg_sinfo_fspace, hbool_t *continue_alloc_fsm);
 
 /* Free-space type manager routines */
@@ -141,7 +146,7 @@ hbool_t H5_PKG_INIT_VAR = FALSE;
  *-------------------------------------------------------------------------
  */
 herr_t
-H5MF_init_merge_flags(H5F_t *f)
+H5MF_init_merge_flags(H5F_shared_t *f_sh)
 {
     H5MF_aggr_merge_t mapping_type;     /* Type of free list mapping */
     H5FD_mem_t type;                    /* Memory type for iteration */
@@ -151,9 +156,8 @@ H5MF_init_merge_flags(H5F_t *f)
     FUNC_ENTER_NOAPI(FAIL)
 
     /* check args */
-    HDassert(f);
-    HDassert(f->shared);
-    HDassert(f->shared->lf);
+    HDassert(f_sh);
+    HDassert(f_sh->lf);
 
     /* Iterate over all the free space types to determine if sections of that type
      *  can merge with the metadata or small 'raw' data aggregator
@@ -161,21 +165,21 @@ H5MF_init_merge_flags(H5F_t *f)
     all_same = TRUE;
     for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
         /* Check for any different type mappings */
-        if(f->shared->fs_type_map[type] != f->shared->fs_type_map[H5FD_MEM_DEFAULT]) {
+        if(f_sh->fs_type_map[type] != f_sh->fs_type_map[H5FD_MEM_DEFAULT]) {
             all_same = FALSE;
             break;
         } /* end if */
 
     /* Check for all allocation types mapping to the same free list type */
     if(all_same) {
-        if(f->shared->fs_type_map[H5FD_MEM_DEFAULT] == H5FD_MEM_DEFAULT)
+        if(f_sh->fs_type_map[H5FD_MEM_DEFAULT] == H5FD_MEM_DEFAULT)
             mapping_type = H5MF_AGGR_MERGE_SEPARATE;
         else
             mapping_type = H5MF_AGGR_MERGE_TOGETHER;
     } /* end if */
     else {
         /* Check for raw data mapping into same list as metadata */
-        if(f->shared->fs_type_map[H5FD_MEM_DRAW] == f->shared->fs_type_map[H5FD_MEM_SUPER])
+        if(f_sh->fs_type_map[H5FD_MEM_DRAW] == f_sh->fs_type_map[H5FD_MEM_SUPER])
             mapping_type = H5MF_AGGR_MERGE_SEPARATE;
         else {
             hbool_t all_metadata_same;              /* Whether all metadata go in same free list */
@@ -188,7 +192,7 @@ H5MF_init_merge_flags(H5F_t *f)
                 /* (global heap is treated as raw data) */
                 if(type != H5FD_MEM_DRAW && type != H5FD_MEM_GHEAP) {
                     /* Check for any different type mappings */
-                    if(f->shared->fs_type_map[type] != f->shared->fs_type_map[H5FD_MEM_SUPER]) {
+                    if(f_sh->fs_type_map[type] != f_sh->fs_type_map[H5FD_MEM_SUPER]) {
                         all_metadata_same = FALSE;
                         break;
                     } /* end if */
@@ -206,30 +210,30 @@ H5MF_init_merge_flags(H5F_t *f)
     switch(mapping_type) {
         case H5MF_AGGR_MERGE_SEPARATE:
             /* Don't merge any metadata together */
-            HDmemset(f->shared->fs_aggr_merge, 0, sizeof(f->shared->fs_aggr_merge));
+            HDmemset(f_sh->fs_aggr_merge, 0, sizeof(f_sh->fs_aggr_merge));
 
             /* Check if merging raw data should be allowed */
             /* (treat global heaps as raw data) */
-            if(H5FD_MEM_DRAW == f->shared->fs_type_map[H5FD_MEM_DRAW] ||
-                    H5FD_MEM_DEFAULT == f->shared->fs_type_map[H5FD_MEM_DRAW]) {
-                f->shared->fs_aggr_merge[H5FD_MEM_DRAW] = H5F_FS_MERGE_RAWDATA;
-                f->shared->fs_aggr_merge[H5FD_MEM_GHEAP] = H5F_FS_MERGE_RAWDATA;
+            if(H5FD_MEM_DRAW == f_sh->fs_type_map[H5FD_MEM_DRAW] ||
+                    H5FD_MEM_DEFAULT == f_sh->fs_type_map[H5FD_MEM_DRAW]) {
+                f_sh->fs_aggr_merge[H5FD_MEM_DRAW] = H5F_FS_MERGE_RAWDATA;
+                f_sh->fs_aggr_merge[H5FD_MEM_GHEAP] = H5F_FS_MERGE_RAWDATA;
 	    } /* end if */
             break;
 
         case H5MF_AGGR_MERGE_DICHOTOMY:
             /* Merge all metadata together (but not raw data) */
-            HDmemset(f->shared->fs_aggr_merge, H5F_FS_MERGE_METADATA, sizeof(f->shared->fs_aggr_merge));
+            HDmemset(f_sh->fs_aggr_merge, H5F_FS_MERGE_METADATA, sizeof(f_sh->fs_aggr_merge));
 
             /* Allow merging raw data allocations together */
             /* (treat global heaps as raw data) */
-            f->shared->fs_aggr_merge[H5FD_MEM_DRAW] = H5F_FS_MERGE_RAWDATA;
-            f->shared->fs_aggr_merge[H5FD_MEM_GHEAP] = H5F_FS_MERGE_RAWDATA;
+            f_sh->fs_aggr_merge[H5FD_MEM_DRAW] = H5F_FS_MERGE_RAWDATA;
+            f_sh->fs_aggr_merge[H5FD_MEM_GHEAP] = H5F_FS_MERGE_RAWDATA;
             break;
 
         case H5MF_AGGR_MERGE_TOGETHER:
             /* Merge all allocation types together */
-            HDmemset(f->shared->fs_aggr_merge, (H5F_FS_MERGE_METADATA | H5F_FS_MERGE_RAWDATA), sizeof(f->shared->fs_aggr_merge));
+            HDmemset(f_sh->fs_aggr_merge, (H5F_FS_MERGE_METADATA | H5F_FS_MERGE_RAWDATA), sizeof(f_sh->fs_aggr_merge));
             break;
 
         default:
@@ -254,31 +258,32 @@ done:
  *-------------------------------------------------------------------------
  */
 void
-H5MF__alloc_to_fs_type(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5F_mem_page_t *fs_type)
+H5MF__alloc_to_fs_type(H5F_shared_t *f_sh, H5FD_mem_t alloc_type, hsize_t size, H5F_mem_page_t *fs_type)
 {
     FUNC_ENTER_PACKAGE_NOERR
 
-    HDassert(f);
+    /* Check arguments */
+    HDassert(f_sh);
     HDassert(fs_type);
 
-    if(H5F_PAGED_AGGR(f)) { /* paged aggregation */
-        if(size >= f->shared->fs_page_size) {
-            if(H5F_HAS_FEATURE(f, H5FD_FEAT_PAGED_AGGR)) { /* multi or split driver */
+    if(H5F_SHARED_PAGED_AGGR(f_sh)) { /* paged aggregation */
+        if(size >= f_sh->fs_page_size) {
+            if(H5F_SHARED_HAS_FEATURE(f_sh, H5FD_FEAT_PAGED_AGGR)) { /* multi or split driver */
                 /* For non-contiguous address space, map to large size free-space manager for each alloc_type */
-                if(H5FD_MEM_DEFAULT == f->shared->fs_type_map[alloc_type]) 
-                    *fs_type = (H5F_mem_page_t) (alloc_type + (H5FD_MEM_NTYPES - 1));
+                if(H5FD_MEM_DEFAULT == f_sh->fs_type_map[alloc_type])
+                    *fs_type = (H5F_mem_page_t)(alloc_type + (H5FD_MEM_NTYPES - 1));
                 else
-                    *fs_type = (H5F_mem_page_t) (f->shared->fs_type_map[alloc_type] + (H5FD_MEM_NTYPES - 1));
+                    *fs_type = (H5F_mem_page_t)(f_sh->fs_type_map[alloc_type] + (H5FD_MEM_NTYPES - 1));
             } /* end if */
             else
                 /* For contiguous address space, map to generic large size free-space manager */
                 *fs_type = H5F_MEM_PAGE_GENERIC; /* H5F_MEM_PAGE_SUPER */
         } /* end if */
         else
-            *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f, alloc_type);
+            *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f_sh, alloc_type);
     } /* end if */
     else /* non-paged aggregation */
-        *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f, alloc_type);
+        *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f_sh, alloc_type);
 
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5MF__alloc_to_fs_type() */
@@ -340,7 +345,7 @@ H5MF__open_fstype(H5F_t *f, H5F_mem_page_t type)
     } /* end else */
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -428,7 +433,7 @@ H5MF__create_fstype(H5F_t *f, H5F_mem_page_t type)
     } /* end else */
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -544,7 +549,7 @@ H5MF__delete_fstype(H5F_t *f, H5F_mem_page_t type)
     f->shared->fs_state[type] = H5F_FS_STATE_DELETING;
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -620,7 +625,6 @@ done:
     FUNC_LEAVE_NOAPI_TAG(ret_value)
 } /* end H5MF__close_fstype() */
 
-
 
 /*-------------------------------------------------------------------------
  * Function:    H5MF__add_sect
@@ -649,7 +653,7 @@ H5MF__add_sect(H5F_t *f, H5FD_mem_t alloc_type, H5FS_t *fspace, H5MF_free_sectio
     HDassert(fspace);
     HDassert(node);
 
-    H5MF__alloc_to_fs_type(f, alloc_type, node->sect_info.size, &fs_type);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, node->sect_info.size, &fs_type);
 
     /* Construct user data for callbacks */
     udata.f = f;
@@ -658,7 +662,7 @@ H5MF__add_sect(H5F_t *f, H5FD_mem_t alloc_type, H5FS_t *fspace, H5MF_free_sectio
     udata.allow_eoa_shrink_only = FALSE;
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_is_self_referential(f, fspace))
+    if(H5MF__fsm_is_self_referential(f->shared, fspace))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -708,7 +712,7 @@ H5MF__find_sect(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5FS_t *fspace,
     HDassert(fspace);
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_is_self_referential(f, fspace))
+    if(H5MF__fsm_is_self_referential(f->shared, fspace))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -801,14 +805,14 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
     HDassert(f->shared->lf);
     HDassert(size > 0);
 
-    H5MF__alloc_to_fs_type(f, alloc_type, size, &fs_type);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, size, &fs_type);
 
 #ifdef H5MF_ALLOC_DEBUG_MORE
 HDfprintf(stderr, "%s: Check 1.0\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, fs_type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -907,15 +911,15 @@ H5MF__alloc_pagefs(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size)
 HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_type, size);
 #endif /* H5MF_ALLOC_DEBUG */
 
-    H5MF__alloc_to_fs_type(f, alloc_type, size, &ptype);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, size, &ptype);
 
     switch(ptype) {
-	    case H5F_MEM_PAGE_GENERIC:  
-	    case H5F_MEM_PAGE_LARGE_BTREE:
-	    case H5F_MEM_PAGE_LARGE_DRAW:
-	    case H5F_MEM_PAGE_LARGE_GHEAP:
-	    case H5F_MEM_PAGE_LARGE_LHEAP:
-	    case H5F_MEM_PAGE_LARGE_OHDR:
+        case H5F_MEM_PAGE_GENERIC:
+        case H5F_MEM_PAGE_LARGE_BTREE:
+        case H5F_MEM_PAGE_LARGE_DRAW:
+        case H5F_MEM_PAGE_LARGE_GHEAP:
+        case H5F_MEM_PAGE_LARGE_LHEAP:
+        case H5F_MEM_PAGE_LARGE_OHDR:
         {
             haddr_t eoa;            /* EOA for the file */
             hsize_t frag_size = 0;  /* Fragment size */
@@ -952,7 +956,7 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
         }
         break;
 
-        case H5F_MEM_PAGE_META: 
+        case H5F_MEM_PAGE_META:
         case H5F_MEM_PAGE_DRAW:
         case H5F_MEM_PAGE_BTREE:
         case H5F_MEM_PAGE_GHEAP:
@@ -980,13 +984,13 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
 
             node = NULL;
 
-            /* Insert the new page into the Page Buffer list of new pages so 
+            /* Insert the new page into the Page Buffer list of new pages so
                we don't read an empty page from disk */
-            if(f->shared->page_buf != NULL && H5PB_add_new_page(f, alloc_type, new_page) < 0)
+            if(f->shared->page_buf != NULL && H5PB_add_new_page(f->shared, alloc_type, new_page) < 0)
                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, HADDR_UNDEF, "can't add new page to Page Buffer new page list")
 
             ret_value = new_page;
-        } 
+        }
         break;
 
         case H5F_MEM_PAGE_NTYPES:
@@ -1108,10 +1112,10 @@ HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUN
         HGOTO_DONE(SUCCEED)
     HDassert(addr != 0);        /* Can't deallocate the superblock :-) */
 
-    H5MF__alloc_to_fs_type(f, alloc_type, size, &fs_type);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, size, &fs_type);
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, fs_type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -1133,11 +1137,10 @@ HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUN
     /* If it's metadata, check if the space to free intersects with the file's
      * metadata accumulator
      */
-    if(H5FD_MEM_DRAW != alloc_type) {
+    if(H5FD_MEM_DRAW != alloc_type)
         /* Check if the space to free intersects with the file's metadata accumulator */
-        if(H5F__accum_free(f, alloc_type, addr, size) < 0)
+        if(H5F__accum_free(f->shared, alloc_type, addr, size) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't check free space intersection w/metadata accumulator")
-    } /* end if */
 
     /* Check if the free space manager for the file has been initialized */
     if(!f->shared->fs_man[fs_type]) {
@@ -1326,10 +1329,10 @@ HDfprintf(stderr, "%s: Entering: alloc_type = %u, addr = %a, size = %Hu, extra_r
     } /* end if */
 
     /* Get free space type from allocation type */
-    H5MF__alloc_to_fs_type(f, alloc_type, size, &fs_type);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, size, &fs_type);
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, fs_type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -1477,10 +1480,10 @@ HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUN
     HDassert(sect_cls);
 
     /* Get free space type from allocation type */
-    H5MF__alloc_to_fs_type(f, alloc_type, size, &fs_type);
+    H5MF__alloc_to_fs_type(f->shared, alloc_type, size, &fs_type);
 
     /* Set the ring type in the API context */
-    if(H5MF__fsm_type_is_self_referential(f, fs_type))
+    if(H5MF__fsm_type_is_self_referential(f->shared, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -1553,11 +1556,11 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
     if(H5F_PAGED_AGGR(f)) {
         if((ret_value = H5MF__close_pagefs(f)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close free-space managers for 'page' file space")
-    }
+    } /* end if */
     else {
         if((ret_value = H5MF__close_aggrfs(f)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close free-space managers for 'aggr' file space")
-    }
+    } /* end else */
 
 done:
 #ifdef H5MF_ALLOC_DEBUG
@@ -1663,10 +1666,10 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
      *
      * The situation is further complicated if a cache image exists
      * and had not yet been loaded into the metadata cache.  In this
-     * case, call H5AC_force_cache_image_load() instead of 
+     * case, call H5AC_force_cache_image_load() instead of
      * H5MF_tidy_self_referential_fsm_hack().  H5AC_force_cache_image_load()
-     * will load the cache image, and then call 
-     * H5MF_tidy_self_referential_fsm_hack() to discard the cache image 
+     * will load the cache image, and then call
+     * H5MF_tidy_self_referential_fsm_hack() to discard the cache image
      * block.
      */
 
@@ -1680,12 +1683,12 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
     if(H5F_PAGED_AGGR(f)) {
         H5F_mem_page_t ptype; 	/* Memory type for iteration */
 
-        /* Iterate over all the free space types that have managers and 
-         * get each free list's space 
+        /* Iterate over all the free space types that have managers and
+         * get each free list's space
          */
         for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
             /* Test to see if we need to switch rings -- do so if required */
-            if(H5MF__fsm_type_is_self_referential(f, ptype))
+            if(H5MF__fsm_type_is_self_referential(f->shared, ptype))
                 needed_ring = H5AC_RING_MDFSM;
             else
                 needed_ring = H5AC_RING_RDFSM;
@@ -1702,12 +1705,12 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
     else {
         H5FD_mem_t type;          	/* Memory type for iteration */
 
-        /* Iterate over all the free space types that have managers and 
-         * get each free list's space 
+        /* Iterate over all the free space types that have managers and
+         * get each free list's space
          */
         for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
             /* Test to see if we need to switch rings -- do so if required */
-            if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+            if(H5MF__fsm_type_is_self_referential(f->shared, (H5F_mem_page_t)type))
                 needed_ring = H5AC_RING_MDFSM;
             else
                 needed_ring = H5AC_RING_RDFSM;
@@ -1824,9 +1827,9 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
         for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
             if(f->shared->fs_man[type]) {
                 /* Test to see if we need to switch rings -- do so if required */
-                if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+                if(H5MF__fsm_type_is_self_referential(f->shared, (H5F_mem_page_t)type))
                     needed_ring = H5AC_RING_MDFSM;
-                else 
+                else
                     needed_ring = H5AC_RING_RDFSM;
 
                 if(needed_ring != curr_ring) {
@@ -1974,7 +1977,7 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
 
         /* gather data for the free space manager superblock extension message.
          * Only need addresses of FSMs and eoa prior to allocation of
-         * file space for the self referential free space managers.  Other 
+         * file space for the self referential free space managers.  Other
          * data was gathered above.
          */
         for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
@@ -1990,7 +1993,7 @@ HDfprintf(stderr, "%s: Entering\n", FUNC);
         for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
             if(f->shared->fs_man[ptype]) {
                 /* Test to see if we need to switch rings -- do so if required */
-                if(H5MF__fsm_type_is_self_referential(f, ptype))
+                if(H5MF__fsm_type_is_self_referential(f->shared, ptype))
                     needed_ring = H5AC_RING_MDFSM;
                 else
                     needed_ring = H5AC_RING_RDFSM;
@@ -2125,7 +2128,7 @@ H5MF__close_shrink_eoa(H5F_t *f)
             for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
                 if(f->shared->fs_man[ptype]) {
                     /* Test to see if we need to switch rings -- do so if required */
-                    if(H5MF__fsm_type_is_self_referential(f, ptype))
+                    if(H5MF__fsm_type_is_self_referential(f->shared, ptype))
                         needed_ring = H5AC_RING_MDFSM;
                     else
                         needed_ring = H5AC_RING_RDFSM;
@@ -2149,7 +2152,7 @@ H5MF__close_shrink_eoa(H5F_t *f)
             for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
                 if(f->shared->fs_man[type]) {
                     /* Test to see if we need to switch rings -- do so if required */
-                    if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+                    if(H5MF__fsm_type_is_self_referential(f->shared, (H5F_mem_page_t)type))
                         needed_ring = H5AC_RING_MDFSM;
                     else
                         needed_ring = H5AC_RING_RDFSM;
@@ -2269,7 +2272,7 @@ H5MF_get_freespace(H5F_t *f, hsize_t *tot_space, hsize_t *meta_size)
         } /* end if */
 
         /* Test to see if we need to switch rings -- do so if required */
-        if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+        if(H5MF__fsm_type_is_self_referential(f->shared, (H5F_mem_page_t)type))
             needed_ring = H5AC_RING_MDFSM;
         else
             needed_ring = H5AC_RING_RDFSM;
@@ -2299,7 +2302,7 @@ H5MF_get_freespace(H5F_t *f, hsize_t *tot_space, hsize_t *meta_size)
     /* Close the free-space managers if they were opened earlier in this routine */
     for(type = start_type; type < end_type; H5_INC_ENUM(H5F_mem_page_t, type)) {
         /* Test to see if we need to switch rings -- do so if required */
-        if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+        if(H5MF__fsm_type_is_self_referential(f->shared, (H5F_mem_page_t)type))
             needed_ring = H5AC_RING_MDFSM;
         else
             needed_ring = H5AC_RING_RDFSM;
@@ -2405,7 +2408,7 @@ H5MF_get_free_sections(H5F_t *f, H5FD_mem_t type, size_t nsects, H5F_sect_info_t
         size_t nums = 0;		/* The number of free-space sections */
 
         /* Test to see if we need to switch rings -- do so if required */
-        if(H5MF__fsm_type_is_self_referential(f, ty))
+        if(H5MF__fsm_type_is_self_referential(f->shared, ty))
             needed_ring = H5AC_RING_MDFSM;
         else
             needed_ring = H5AC_RING_RDFSM;
@@ -2731,7 +2734,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
                 break;
 
             for(mem_type = H5FD_MEM_SUPER; mem_type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5F_mem_t, mem_type)) {
-                H5MF__alloc_to_fs_type(f, mem_type, alloc_size, &fsm_type);
+                H5MF__alloc_to_fs_type(f->shared, mem_type, alloc_size, &fsm_type);
 
                 if(pass_count == 0) { /* this is the first pass */
                     HDassert(fsm_type > H5F_MEM_PAGE_DEFAULT);
@@ -2764,7 +2767,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
 
                     if(f->shared->fs_man[fsm_type]) {
                         /* Test to see if we need to switch rings -- do so if required */
-                        if(H5MF__fsm_type_is_self_referential(f, fsm_type))
+                        if(H5MF__fsm_type_is_self_referential(f->shared, fsm_type))
                              needed_ring = H5AC_RING_MDFSM;
                         else
                              needed_ring = H5AC_RING_RDFSM;
@@ -2876,7 +2879,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
                 break;
 
             for(mem_type = H5FD_MEM_SUPER; mem_type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5F_mem_t, mem_type)) {
-                H5MF__alloc_to_fs_type(f, mem_type, alloc_size, &fsm_type);
+                H5MF__alloc_to_fs_type(f->shared, mem_type, alloc_size, &fsm_type);
 
                 if(pass_count == 0) { /* this is the first pass */
                     HDassert(fsm_type > H5F_MEM_PAGE_DEFAULT);
@@ -2890,7 +2893,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
                     HDassert(FALSE);
 
                 /* Test to see if we need to switch rings -- do so if required */
-                if(H5MF__fsm_type_is_self_referential(f, fsm_type))
+                if(H5MF__fsm_type_is_self_referential(f->shared, fsm_type))
                     needed_ring = H5AC_RING_MDFSM;
                 else
                     needed_ring = H5AC_RING_RDFSM;
@@ -2913,7 +2916,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
                          * that this is also the deciding factor as to whether a FSM 
                          * in in the raw data FSM ring.
                          */
-                        if(!H5MF__fsm_type_is_self_referential(f, fsm_type)) {
+                        if(!H5MF__fsm_type_is_self_referential(f->shared, fsm_type)) {
                             /* The current ring should be H5AC_RING_RDFSM */
                             HDassert(curr_ring == H5AC_RING_RDFSM);
 
@@ -3120,8 +3123,8 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hbool_t *fsm_settled)
         /* should only be called if file is opened R/W */
         HDassert(H5F_INTENT(f) & H5F_ACC_RDWR);
 
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fs_type);
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fs_type);
+        H5MF__alloc_to_fs_type(f->shared, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fs_type);
+        H5MF__alloc_to_fs_type(f->shared, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fs_type);
 
         HDassert(sm_fshdr_fs_type > H5F_MEM_PAGE_DEFAULT);
         HDassert(sm_fshdr_fs_type < H5F_MEM_PAGE_LARGE_SUPER);
@@ -3137,8 +3140,8 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hbool_t *fsm_settled)
         sm_sinfo_fspace = f->shared->fs_man[sm_fssinfo_fs_type];
 
         if(H5F_PAGED_AGGR(f)) {
-            H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fs_type);
-            H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fs_type);
+            H5MF__alloc_to_fs_type(f->shared, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fs_type);
+            H5MF__alloc_to_fs_type(f->shared, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fs_type);
 
             HDassert(lg_fshdr_fs_type >= H5F_MEM_PAGE_LARGE_SUPER);
             HDassert(lg_fshdr_fs_type < H5F_MEM_PAGE_NTYPES);
@@ -3278,14 +3281,13 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hbool_t *fsm_settled)
                 lg_sinfo_fspace = f->shared->fs_man[lg_fssinfo_fs_type];
             }
 
-            if(H5MF__continue_alloc_fsm(f, sm_hdr_fspace, sm_sinfo_fspace, lg_hdr_fspace, lg_sinfo_fspace, &continue_alloc_fsm) < 0)
+            if(H5MF__continue_alloc_fsm(f->shared, sm_hdr_fspace, sm_sinfo_fspace, lg_hdr_fspace, lg_sinfo_fspace, &continue_alloc_fsm) < 0)
                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate lg sinfo FSM file space")
-
         } while(continue_alloc_fsm);
 
 
         /* All free space managers should have file space allocated for them
-         * now, and should see no further allocations / deallocations.  
+         * now, and should see no further allocations / deallocations.
          * For backward compatibility, store the eoa in f->shared->eoa_fsm_fsalloc 
          * which will be set to fsinfo.eoa_pre_fsm_fsalloc when we actually write 
          * the free-space info message to the superblock extension.
@@ -3293,7 +3295,7 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hbool_t *fsm_settled)
          * the new solution.
          */
         /* Get the eoa after allocation of file space for the self referential
-         * free space managers.  Assuming no cache image, this should be the 
+         * free space managers.  Assuming no cache image, this should be the
          * final EOA of the file.
          */
         if(HADDR_UNDEF == (eoa_fsm_fsalloc = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)))
@@ -3328,42 +3330,39 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF__continue_alloc_fsm(H5F_t *f, H5FS_t *sm_hdr_fspace, H5FS_t *sm_sinfo_fspace, 
+H5MF__continue_alloc_fsm(H5F_shared_t *f_sh, H5FS_t *sm_hdr_fspace, H5FS_t *sm_sinfo_fspace, 
     H5FS_t  *lg_hdr_fspace, H5FS_t *lg_sinfo_fspace, hbool_t *continue_alloc_fsm)
 {
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     /* Sanity checks */
-    HDassert(f);
-    HDassert(f->shared);
+    HDassert(f_sh);
     HDassert(continue_alloc_fsm);
 
     /* Check sm_hdr_fspace */
     if(sm_hdr_fspace && sm_hdr_fspace->serial_sect_count > 0 && sm_hdr_fspace->sinfo) {
         H5MF_CHECK_FSM(sm_hdr_fspace, continue_alloc_fsm);
-    }
+    } /* end if */
 
-    if(!(*continue_alloc_fsm)) {
+    if(!(*continue_alloc_fsm))
         if(sm_sinfo_fspace && sm_sinfo_fspace != sm_hdr_fspace &&
            sm_sinfo_fspace->serial_sect_count > 0 && sm_sinfo_fspace->sinfo) {
             H5MF_CHECK_FSM(sm_hdr_fspace, continue_alloc_fsm);
-        }
-    }
+        } /* end if */
 
-    if(H5F_PAGED_AGGR(f) && !(*continue_alloc_fsm)) {
+    if(H5F_SHARED_PAGED_AGGR(f_sh) && !(*continue_alloc_fsm)) {
         /* Check lg_hdr_fspace */
         if(lg_hdr_fspace && lg_hdr_fspace->serial_sect_count > 0 && lg_hdr_fspace->sinfo) {
             H5MF_CHECK_FSM(lg_hdr_fspace, continue_alloc_fsm);
-        }
+        } /* end if */
 
         /* Check lg_sinfo_fspace */
-        if(!(*continue_alloc_fsm)) {
+        if(!(*continue_alloc_fsm))
             if(lg_sinfo_fspace && lg_sinfo_fspace != lg_hdr_fspace &&
-               lg_sinfo_fspace->serial_sect_count > 0 && lg_sinfo_fspace->sinfo) {
+                    lg_sinfo_fspace->serial_sect_count > 0 && lg_sinfo_fspace->sinfo) {
                 H5MF_CHECK_FSM(lg_sinfo_fspace, continue_alloc_fsm);
-            }
-         }
-    }
+            } /* end if */
+    } /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5MF__continue_alloc_fsm() */
@@ -3382,8 +3381,8 @@ H5MF__continue_alloc_fsm(H5F_t *f, H5FS_t *sm_hdr_fspace, H5FS_t *sm_sinfo_fspac
  *
  *-------------------------------------------------------------------------
  */
-hbool_t
-H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type)
+static hbool_t
+H5MF__fsm_type_is_self_referential(H5F_shared_t *f_sh, H5F_mem_page_t fsm_type)
 {
     H5F_mem_page_t sm_fshdr_fsm;
     H5F_mem_page_t sm_fssinfo_fsm;
@@ -3391,26 +3390,25 @@ H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type)
     H5F_mem_page_t lg_fssinfo_fsm;
     hbool_t result = FALSE;
 
-    FUNC_ENTER_PACKAGE_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(f->shared);
+    HDassert(f_sh);
     HDassert(fsm_type >= H5F_MEM_PAGE_DEFAULT);
     HDassert(fsm_type < H5F_MEM_PAGE_NTYPES);
 
-    H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
-    H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
+    H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
+    H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
 
-    if(H5F_PAGED_AGGR(f)) {
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fsm);
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fsm);
+    if(H5F_SHARED_PAGED_AGGR(f_sh)) {
+        H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_HDR, f_sh->fs_page_size + 1, &lg_fshdr_fsm);
+        H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_SINFO, f_sh->fs_page_size + 1, &lg_fssinfo_fsm);
 
         result = (fsm_type == sm_fshdr_fsm) || (fsm_type == sm_fssinfo_fsm)
                 || (fsm_type == lg_fshdr_fsm) || (fsm_type == lg_fssinfo_fsm);
     } /* end if */
     else {
-        /* In principle, fsm_type should always be less than 
+        /* In principle, fsm_type should always be less than
          * H5F_MEM_PAGE_LARGE_SUPER whenever paged aggregation
          * is not enabled.  However, since there is code that does
          * not observe this principle, force the result to FALSE if
@@ -3440,7 +3438,7 @@ H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type)
  *-------------------------------------------------------------------------
  */
 static hbool_t
-H5MF__fsm_is_self_referential(H5F_t *f, H5FS_t *fspace)
+H5MF__fsm_is_self_referential(H5F_shared_t *f_sh, H5FS_t *fspace)
 {
     H5F_mem_page_t sm_fshdr_fsm;
     H5F_mem_page_t sm_fssinfo_fsm;
@@ -3449,28 +3447,27 @@ H5MF__fsm_is_self_referential(H5F_t *f, H5FS_t *fspace)
     FUNC_ENTER_STATIC_NOERR
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(f->shared);
+    HDassert(f_sh);
     HDassert(fspace);
 
-    H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
-    H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
+    H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
+    H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
 
-    if(H5F_PAGED_AGGR(f)) {
+    if(H5F_SHARED_PAGED_AGGR(f_sh)) {
         H5F_mem_page_t lg_fshdr_fsm;
         H5F_mem_page_t lg_fssinfo_fsm;
 
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fsm);
-        H5MF__alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fsm);
+        H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_HDR, f_sh->fs_page_size + 1, &lg_fshdr_fsm);
+        H5MF__alloc_to_fs_type(f_sh, H5FD_MEM_FSPACE_SINFO, f_sh->fs_page_size + 1, &lg_fssinfo_fsm);
 
-        result = (fspace == f->shared->fs_man[sm_fshdr_fsm]) ||
-                   (fspace == f->shared->fs_man[sm_fssinfo_fsm]) ||
-                   (fspace == f->shared->fs_man[lg_fshdr_fsm]) ||
-                   (fspace == f->shared->fs_man[lg_fssinfo_fsm]);
+        result = (fspace == f_sh->fs_man[sm_fshdr_fsm]) ||
+                   (fspace == f_sh->fs_man[sm_fssinfo_fsm]) ||
+                   (fspace == f_sh->fs_man[lg_fshdr_fsm]) ||
+                   (fspace == f_sh->fs_man[lg_fssinfo_fsm]);
     } /* end if */
     else
-        result = (fspace == f->shared->fs_man[sm_fshdr_fsm]) ||
-                   (fspace == f->shared->fs_man[sm_fssinfo_fsm]);
+        result = (fspace == f_sh->fs_man[sm_fshdr_fsm]) ||
+                   (fspace == f_sh->fs_man[sm_fssinfo_fsm]);
 
     FUNC_LEAVE_NOAPI(result)
 } /* H5MF__fsm_is_self_referential() */
diff --git a/src/H5MFaggr.c b/src/H5MFaggr.c
index c726341..d716ae2 100644
--- a/src/H5MFaggr.c
+++ b/src/H5MFaggr.c
@@ -194,9 +194,9 @@ HDfprintf(stderr, "%s: type = %u, size = %Hu\n", FUNC, (unsigned)type, size);
      * the cache eventually adjusts/evicts ageout entries and ends up flushing out the
      * same entry that is being serialized (flush_in_progress).
      */ 
-    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FSPACE_STRATEGY_NONE && (!f->closing || !f->shared->fs_persist)) {
+    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FSPACE_STRATEGY_NONE && (!f->shared->closing || !f->shared->fs_persist)) {
 #ifdef REPLACE
-    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FSPACE_STRATEGY_NONE && !f->closing) {
+    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FSPACE_STRATEGY_NONE && !f->shared->closing) {
 #endif
         haddr_t	aggr_frag_addr = HADDR_UNDEF;   /* Address of aggregrator fragment */
         hsize_t	aggr_frag_size = 0;             /* Size of aggregator fragment */
diff --git a/src/H5MFpkg.h b/src/H5MFpkg.h
index ec4aab4..fc398db 100644
--- a/src/H5MFpkg.h
+++ b/src/H5MFpkg.h
@@ -55,11 +55,6 @@
 #define H5MF_FSPACE_SECT_SMALL      1   /* For paged aggregation: "small" meta/raw data section which is < fsp_size) */
 #define H5MF_FSPACE_SECT_LARGE      2   /* For paged aggregation: "large" Section which is >= fsp_size) */
 
-/* For non-paged aggregation: map allocation request type to tracked free-space type */
-/* F -- pointer to H5F_t; T -- H5FD_mem_t */
-#define H5MF_ALLOC_TO_FS_AGGR_TYPE(F, T)                  \
-        ((H5FD_MEM_DEFAULT == (F)->shared->fs_type_map[T]) ? (T) : (F)->shared->fs_type_map[T])
-
 /* Get section class type based on size */
 #define H5MF_SECT_CLASS_TYPE(F, S)                          \
         ((H5F_PAGED_AGGR(F)) ?                              \
@@ -182,13 +177,10 @@ H5_DLLVAR H5FS_section_class_t H5MF_FSPACE_SECT_CLS_LARGE[1];
 /* Allocator routines */
 H5_DLL herr_t H5MF__open_fstype(H5F_t *f, H5F_mem_page_t type);
 H5_DLL herr_t H5MF__start_fstype(H5F_t *f, H5F_mem_page_t type);
-
 H5_DLL htri_t H5MF__find_sect(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5FS_t *fspace, haddr_t *addr);
 H5_DLL herr_t H5MF__add_sect(H5F_t *f, H5FD_mem_t alloc_type, H5FS_t *fspace, H5MF_free_section_t *node);
-
-H5_DLL herr_t H5MF__sects_dump(H5F_t *f, FILE *stream);
-
-H5_DLL void H5MF__alloc_to_fs_type(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5F_mem_page_t *fs_type);
+H5_DLL void H5MF__alloc_to_fs_type(H5F_shared_t *f_sh, H5FD_mem_t alloc_type,
+    hsize_t size, H5F_mem_page_t *fs_type);
 
 /* 'simple/small/large' section routines */
 H5_DLL H5MF_free_section_t *H5MF__sect_new(unsigned ctype, haddr_t sect_off,
@@ -206,6 +198,11 @@ H5_DLL herr_t H5MF__aggr_absorb(const H5F_t *f, H5F_blk_aggr_t *aggr,
 H5_DLL herr_t H5MF__aggr_query(const H5F_t *f, const H5F_blk_aggr_t *aggr,
     haddr_t *addr, hsize_t *size);
 
+/* Debugging routines */
+#ifdef H5MF_ALLOC_DEBUG_DUMP
+H5_DLL herr_t H5MF__sects_dump(H5F_t *f, FILE *stream);
+#endif /* H5MF_ALLOC_DEBUG_DUMP */
+
 /* Testing routines */
 #ifdef H5MF_TESTING
 #endif /* H5MF_TESTING */
diff --git a/src/H5MFprivate.h b/src/H5MFprivate.h
index bd57f05..de1bdfb 100644
--- a/src/H5MFprivate.h
+++ b/src/H5MFprivate.h
@@ -48,7 +48,7 @@
 /***************************************/
 
 /* File space manager routines */
-H5_DLL herr_t H5MF_init_merge_flags(H5F_t *f);
+H5_DLL herr_t H5MF_init_merge_flags(H5F_shared_t *f_sh);
 H5_DLL herr_t H5MF_get_freespace(H5F_t *f, hsize_t *tot_space, hsize_t *meta_size);
 H5_DLL herr_t H5MF_close(H5F_t *f);
 H5_DLL herr_t H5MF_try_close(H5F_t *f);
diff --git a/src/H5MFsection.c b/src/H5MFsection.c
index 3ebc5c8..f661ef9 100644
--- a/src/H5MFsection.c
+++ b/src/H5MFsection.c
@@ -776,7 +776,7 @@ H5MF__sect_small_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2
         /* Note: Large metadata page bypasses the PB cache */
         /* Note: Update of raw data page (large or small sized) is handled by the PB cache */
         if(udata->f->shared->page_buf != NULL && udata->alloc_type != H5FD_MEM_DRAW)
-            if(H5PB_remove_entry(udata->f, (*sect1)->sect_info.addr) < 0)
+            if(H5PB_remove_entry(udata->f->shared, (*sect1)->sect_info.addr) < 0)
                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free merged section")
 
         if(H5MF__sect_free((H5FS_section_info_t *)(*sect1)) < 0)
diff --git a/src/H5Ocache_image.c b/src/H5Ocache_image.c
index 7336211..70d9ef5 100644
--- a/src/H5Ocache_image.c
+++ b/src/H5Ocache_image.c
@@ -325,7 +325,7 @@ H5O__mdci_delete(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, void *_mesg)
 
 
 
-        if(f->closing) {
+        if(f->shared->closing) {
 
             /* Get the eoa, and verify that it has the expected value */
             if(HADDR_UNDEF == (final_eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)) )
diff --git a/src/H5Ochunk.c b/src/H5Ochunk.c
index 94301b3..9ce5a46 100644
--- a/src/H5Ochunk.c
+++ b/src/H5Ochunk.c
@@ -331,7 +331,7 @@ H5O__chunk_update_idx(H5F_t *f, H5O_t *oh, unsigned idx)
     H5O_chk_cache_ud_t chk_udata;       /* User data for loading chunk */
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_PACKAGE
+    FUNC_ENTER_PACKAGE_TAG(oh->cache_info.addr)
 
     /* check args */
     HDassert(f);
diff --git a/src/H5PB.c b/src/H5PB.c
index 25c5f43..6c83217 100644
--- a/src/H5PB.c
+++ b/src/H5PB.c
@@ -124,8 +124,8 @@ typedef struct {
 /* Local Prototypes */
 /********************/
 static herr_t H5PB__insert_entry(H5PB_t *page_buf, H5PB_entry_t *page_entry);
-static htri_t H5PB__make_space(H5F_t *f, H5PB_t *page_buf, H5FD_mem_t inserted_type);
-static herr_t H5PB__write_entry(H5F_t *f, H5PB_entry_t *page_entry);
+static htri_t H5PB__make_space(H5F_shared_t *f_sh, H5PB_t *page_buf, H5FD_mem_t inserted_type);
+static herr_t H5PB__write_entry(H5F_shared_t *f_sh, H5PB_entry_t *page_entry);
 
 
 /*********************/
@@ -289,7 +289,7 @@ H5PB_print_stats(const H5PB_t *page_buf)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_create(H5F_t *f, size_t size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc)
+H5PB_create(H5F_shared_t *f_sh, size_t size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc)
 {
     H5PB_t *page_buf = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
@@ -297,20 +297,19 @@ H5PB_create(H5F_t *f, size_t size, unsigned page_buf_min_meta_perc, unsigned pag
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
-    HDassert(f->shared);
+    HDassert(f_sh);
 
     /* Check args */
-    if(f->shared->fs_strategy != H5F_FSPACE_STRATEGY_PAGE)
+    if(f_sh->fs_strategy != H5F_FSPACE_STRATEGY_PAGE)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "Enabling Page Buffering requires PAGE file space strategy")
     /* round down the size if it is larger than the page size */
-    else if(size > f->shared->fs_page_size) {
+    else if(size > f_sh->fs_page_size) {
         hsize_t temp_size;
 
-        temp_size = (size / f->shared->fs_page_size) * f->shared->fs_page_size;
+        temp_size = (size / f_sh->fs_page_size) * f_sh->fs_page_size;
         H5_CHECKED_ASSIGN(size, size_t, temp_size, hsize_t);
     } /* end if */
-    else if(0 != size % f->shared->fs_page_size)
+    else if(0 != size % f_sh->fs_page_size)
         HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTINIT, FAIL, "Page Buffer size must be >= to the page size")
 
     /* Allocate the new page buffering structure */
@@ -318,15 +317,15 @@ H5PB_create(H5F_t *f, size_t size, unsigned page_buf_min_meta_perc, unsigned pag
 	HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "memory allocation failed")
 
     page_buf->max_size = size;
-    H5_CHECKED_ASSIGN(page_buf->page_size, size_t, f->shared->fs_page_size, hsize_t);
+    H5_CHECKED_ASSIGN(page_buf->page_size, size_t, f_sh->fs_page_size, hsize_t);
     page_buf->min_meta_perc = page_buf_min_meta_perc;
     page_buf->min_raw_perc = page_buf_min_raw_perc;
 
     /* Calculate the minimum page count for metadata and raw data
-     * based on the fractions provided 
+     * based on the fractions provided
      */
-    page_buf->min_meta_count = (unsigned)((size * page_buf_min_meta_perc) / (f->shared->fs_page_size * 100));
-    page_buf->min_raw_count = (unsigned)((size * page_buf_min_raw_perc) / (f->shared->fs_page_size * 100));
+    page_buf->min_meta_count = (unsigned)((size * page_buf_min_meta_perc) / (f_sh->fs_page_size * 100));
+    page_buf->min_raw_count = (unsigned)((size * page_buf_min_raw_perc) / (f_sh->fs_page_size * 100));
 
     if(NULL == (page_buf->slist_ptr = H5SL_create(H5SL_TYPE_HADDR, NULL)))
         HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTCREATE, FAIL, "can't create skip list")
@@ -336,7 +335,7 @@ H5PB_create(H5F_t *f, size_t size, unsigned page_buf_min_meta_perc, unsigned pag
     if(NULL == (page_buf->page_fac = H5FL_fac_init(page_buf->page_size)))
         HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTINIT, FAIL, "can't create page factory")
 
-    f->shared->page_buf = page_buf;
+    f_sh->page_buf = page_buf;
 
 done:
     if(ret_value < 0) {
@@ -370,18 +369,18 @@ static herr_t
 H5PB__flush_cb(void *item, void H5_ATTR_UNUSED *key, void *_op_data)
 {
     H5PB_entry_t *page_entry = (H5PB_entry_t *)item;    /* Pointer to page entry node */
-    H5F_t *f = (H5F_t *)_op_data;
+    H5F_shared_t *f_sh = (H5F_shared_t *)_op_data;
     herr_t  ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_STATIC
 
     /* Sanity checks */
     HDassert(page_entry);
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Flush the page if it's dirty */
     if(page_entry->is_dirty)
-        if(H5PB__write_entry(f, page_entry) < 0)
+        if(H5PB__write_entry(f_sh, page_entry) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
 
 done:
@@ -401,21 +400,21 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_flush(H5F_t *f)
+H5PB_flush(H5F_shared_t *f_sh)
 {
     herr_t  ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Flush all the entries in the PB skiplist, if we have write access on the file */
-    if(f->shared->page_buf && (H5F_ACC_RDWR & H5F_INTENT(f))) {
-        H5PB_t *page_buf = f->shared->page_buf;
+    if(f_sh->page_buf && (H5F_ACC_RDWR & H5F_SHARED_INTENT(f_sh))) {
+        H5PB_t *page_buf = f_sh->page_buf;
 
         /* Iterate over all entries in page buffer skip list */
-        if(H5SL_iterate(page_buf->slist_ptr, H5PB__flush_cb, (void *)f))
+        if(H5SL_iterate(page_buf->slist_ptr, H5PB__flush_cb, f_sh))
             HGOTO_ERROR(H5E_PAGEBUF, H5E_BADITER, FAIL, "can't flush page buffer skip list")
     } /* end if */
 
@@ -473,21 +472,21 @@ H5PB__dest_cb(void *item, void H5_ATTR_UNUSED *key, void *_op_data)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_dest(H5F_t *f)
+H5PB_dest(H5F_shared_t *f_sh)
 {
     herr_t  ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* flush and destroy the page buffer, if it exists */
-    if(f->shared->page_buf) {
-        H5PB_t *page_buf = f->shared->page_buf;
+    if(f_sh->page_buf) {
+        H5PB_t *page_buf = f_sh->page_buf;
         H5PB_ud1_t op_data;                 /* Iteration context */
 
-        if(H5PB_flush(f) < 0)
+        if(H5PB_flush(f_sh) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTFLUSH, FAIL, "can't flush page buffer")
 
         /* Set up context info */
@@ -507,7 +506,7 @@ H5PB_dest(H5F_t *f)
         if(H5FL_fac_term(page_buf->page_fac) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTRELEASE, FAIL, "can't destroy page buffer page factory")
 
-        f->shared->page_buf = H5FL_FREE(H5PB_t, page_buf);
+        f_sh->page_buf = H5FL_FREE(H5PB_t, page_buf);
     } /* end if */
 
 done:
@@ -529,16 +528,18 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-herr_t 
-H5PB_add_new_page(H5F_t *f, H5FD_mem_t type, haddr_t page_addr)
+herr_t
+H5PB_add_new_page(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t page_addr)
 {
-    H5PB_t *page_buf = f->shared->page_buf;
-    H5PB_entry_t *page_entry = NULL;    /* pointer to the corresponding page entry */
-    herr_t ret_value = SUCCEED;    /* Return value */
+    H5PB_t *page_buf;                   /* Page buffer to operate on */
+    H5PB_entry_t *page_entry = NULL;    /* Pointer to the corresponding page entry */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
+    HDassert(f_sh);
+    page_buf = f_sh->page_buf;
     HDassert(page_buf);
 
     /* If there is an existing page, this means that at some point the
@@ -624,7 +625,7 @@ H5PB_update_entry(H5PB_t *page_buf, haddr_t addr, size_t size, const void *buf)
  * Function:    H5PB_remove_entry
  *
  * Purpose:     Remove possible metadata entry with ADDR from the PB cache.
- *              This is in response to the data corruption bug from fheap.c 
+ *              This is in response to the data corruption bug from fheap.c
  *              with page buffering + page strategy.
  *              Note: Large metadata page bypasses the PB cache.
  *              Note: Update of raw data page (large or small sized) is handled by the PB cache.
@@ -636,15 +637,17 @@ H5PB_update_entry(H5PB_t *page_buf, haddr_t addr, size_t size, const void *buf)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_remove_entry(const H5F_t *f, haddr_t addr)
+H5PB_remove_entry(const H5F_shared_t *f_sh, haddr_t addr)
 {
-    H5PB_t *page_buf = f->shared->page_buf;
-    H5PB_entry_t *page_entry = NULL;        /* pointer to the page entry being searched */
-    herr_t ret_value = SUCCEED;             /* Return value */
+    H5PB_t *page_buf;                   /* Page buffer to operate on */
+    H5PB_entry_t *page_entry = NULL;    /* Pointer to the page entry being searched */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
+    HDassert(f_sh);
+    page_buf = f_sh->page_buf;
     HDassert(page_buf);
 
     /* Search for address in the skip list */
@@ -674,7 +677,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function:	H5PB_read
  *
- * Purpose:	Reads in the data from the page containing it if it exists 
+ * Purpose:	Reads in the data from the page containing it if it exists
  *              in the PB cache; otherwise reads in the page through the VFD.
  *
  * Return:	Non-negative on success/Negative on failure
@@ -684,7 +687,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/)
+H5PB_read(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/)
 {
     H5PB_t *page_buf;                   /* Page buffering info for this file */
     H5PB_entry_t *page_entry;           /* Pointer to the corresponding page entry */
@@ -701,21 +704,21 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
     HDassert(type != H5FD_MEM_GHEAP);
 
     /* Get pointer to page buffer info for this file */
-    page_buf = f->shared->page_buf;
+    page_buf = f_sh->page_buf;
 
 #ifdef H5_HAVE_PARALLEL
-    if(H5F_HAS_FEATURE(f, H5FD_FEAT_HAS_MPI)) {
+    if(H5F_SHARED_HAS_FEATURE(f_sh, H5FD_FEAT_HAS_MPI)) {
 #if 1
         bypass_pb = TRUE;
 #else
         /* MSC - why this stopped working ? */
         int mpi_size;
 
-        if((mpi_size = H5F_mpi_get_size(f)) < 0)
+        if((mpi_size = H5F_shared_mpi_get_size(f_sh)) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "can't retrieve MPI communicator size")
         if(1 != mpi_size)
             bypass_pb = TRUE;
@@ -729,7 +732,7 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
      */
     if(NULL == page_buf || size >= page_buf->page_size ||
            (bypass_pb && H5FD_MEM_DRAW == type)) {
-        if(H5F__accum_read(f, type, addr, size, buf) < 0)
+        if(H5F__accum_read(f_sh, type, addr, size, buf) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_READERROR, FAIL, "read through metadata accumulator failed")
 
         /* Update statistics */
@@ -780,7 +783,7 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
     } /* end else */
 
     /* Translate to file driver I/O info object */
-    file = f->shared->lf;
+    file = f_sh->lf;
 
     /* Copy raw data from dirty pages into the read buffer if the read
        request spans pages in the page buffer*/
@@ -884,7 +887,7 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
                 else
                     page_buf->hits[0]++;
             } /* end if */
-            /* if not found */ 
+            /* if not found */
             else {
                 void *new_page_buf = NULL;
                 size_t page_size = page_buf->page_size;
@@ -895,7 +898,7 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
                     htri_t can_make_space;
 
                     /* check if we can make space in page buffer */
-                    if((can_make_space = H5PB__make_space(f, page_buf, type)) < 0)
+                    if((can_make_space = H5PB__make_space(f_sh, page_buf, type)) < 0)
                         HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "make space in Page buffer Failed")
 
                     /* if make_space returns 0, then we can't use the page
@@ -920,7 +923,7 @@ H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/
                 /* Read page through the VFD layer, but make sure we don't read past the EOA. */
 
                 /* Retrieve the 'eoa' for the file */
-                if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, type)))
+                if(HADDR_UNDEF == (eoa = H5F_shared_get_eoa(f_sh, type)))
                     HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
 
                 /* If the entire page falls outside the EOA, then fail */
@@ -981,7 +984,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
+H5PB_write(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr,
     size_t size, const void *buf)
 {
     H5PB_t *page_buf;                   /* Page buffering info for this file */
@@ -999,20 +1002,20 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity checks */
-    HDassert(f);
+    HDassert(f_sh);
 
     /* Get pointer to page buffer info for this file */
-    page_buf = f->shared->page_buf;
+    page_buf = f_sh->page_buf;
 
 #ifdef H5_HAVE_PARALLEL
-    if(H5F_HAS_FEATURE(f, H5FD_FEAT_HAS_MPI)) {
+    if(H5F_SHARED_HAS_FEATURE(f_sh, H5FD_FEAT_HAS_MPI)) {
 #if 1
         bypass_pb = TRUE;
 #else
         /* MSC - why this stopped working ? */
         int mpi_size;
 
-        if((mpi_size = H5F_mpi_get_size(f)) < 0)
+        if((mpi_size = H5F_shared_mpi_get_size(f_sh)) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "can't retrieve MPI communicator size")
         if(1 != mpi_size)
             bypass_pb = TRUE;
@@ -1025,7 +1028,7 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
      * buffering.
      */
     if(NULL == page_buf || size >= page_buf->page_size || bypass_pb) {
-        if(H5F__accum_write(f, type, addr, size, buf) < 0)
+        if(H5F__accum_write(f_sh, type, addr, size, buf) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "write through metadata accumulator failed")
 
         /* Update statistics */
@@ -1084,7 +1087,7 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
     } /* end else */
 
     /* Translate to file driver I/O info object */
-    file = f->shared->lf;
+    file = f_sh->lf;
 
     /* Check if existing pages for raw data need to be updated since raw data access is not atomic */
     if(H5FD_MEM_DRAW == type && size >= page_buf->page_size) {
@@ -1186,7 +1189,7 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
                 else
                     page_buf->hits[0]++;
             } /* end if */
-            /* If not found */ 
+            /* If not found */
             else {
                 void *new_page_buf;
                 size_t page_size = page_buf->page_size;
@@ -1196,7 +1199,7 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
                     htri_t can_make_space;
 
                     /* Check if we can make space in page buffer */
-                    if((can_make_space = H5PB__make_space(f, page_buf, type)) < 0)
+                    if((can_make_space = H5PB__make_space(f_sh, page_buf, type)) < 0)
                         HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "make space in Page buffer Failed")
 
                     /* If make_space returns 0, then we can't use the page
@@ -1208,14 +1211,14 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
                         /* Write to VFD and return */
                         if(H5FD_write(file, type, addr, size, buf) < 0)
                             HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "driver write request failed")
-                        
+
                         /* Break out of loop */
                         break;
                     } /* end if */
                 } /* end if */
 
                 /* Don't bother searching if there is no write access */
-                if(H5F_ACC_RDWR & H5F_INTENT(f))
+                if(H5F_ACC_RDWR & H5F_SHARED_INTENT(f_sh))
                     /* Lookup & remove the page from the new skip list page if
                      * it exists to see if this is a new page from the MF layer
                      */
@@ -1258,7 +1261,7 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
                     page_entry->type = (H5F_mem_page_t)type;
 
                     /* Retrieve the 'eoa' for the file */
-                    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, type)))
+                    if(HADDR_UNDEF == (eoa = H5F_shared_get_eoa(f_sh, type)))
                         HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
 
                     /* If the entire page falls outside the EOA, then fail */
@@ -1269,8 +1272,8 @@ H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr,
                      * returned will most likely be HADDR_UNDEF, so skip
                      * that check.
                      */
-                    if(!H5F_HAS_FEATURE(f, H5FD_FEAT_HAS_MPI))
-                        if(HADDR_UNDEF == (eof = H5FD_get_eof(f->shared->lf, H5FD_MEM_DEFAULT)))
+                    if(!H5F_SHARED_HAS_FEATURE(f_sh, H5FD_FEAT_HAS_MPI))
+                        if(HADDR_UNDEF == (eof = H5FD_get_eof(f_sh->lf, H5FD_MEM_DEFAULT)))
                             HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eof request failed")
 
                     /* Adjust the read size to not go beyond the EOA */
@@ -1360,26 +1363,19 @@ done:
 /*-------------------------------------------------------------------------
  * Function:	H5PB__make_space()
  *
- * Purpose: ??? 
- *
- *          This function was created without documentation.
- *          What follows is my best understanding of Mohamad's intent.
- *
- *          If necessary and if possible, evict a page from the page 
- *          buffer to make space for the supplied page.  Depending on 
- *	    the page buffer configuration and contents, and the page 
+ * Purpose: If necessary and if possible, evict a page from the page
+ *          buffer to make space for the supplied page.  Depending on
+ *	    the page buffer configuration and contents, and the page
  *          supplied this may or may not be possible.
  *
- *                                             JRM -- 12/22/16
- *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Mohamad Chaarawi
  *
  *-------------------------------------------------------------------------
  */
-static htri_t 
-H5PB__make_space(H5F_t *f, H5PB_t *page_buf, H5FD_mem_t inserted_type)
+static htri_t
+H5PB__make_space(H5F_shared_t *f_sh, H5PB_t *page_buf, H5FD_mem_t inserted_type)
 {
     H5PB_entry_t *page_entry;   /* Pointer to page eviction candidate */
     htri_t ret_value = TRUE;    /* Return value */
@@ -1387,7 +1383,7 @@ H5PB__make_space(H5F_t *f, H5PB_t *page_buf, H5FD_mem_t inserted_type)
     FUNC_ENTER_STATIC
 
     /* Sanity check */
-    HDassert(f);
+    HDassert(f_sh);
     HDassert(page_buf);
 
     /* Get oldest entry */
@@ -1444,7 +1440,7 @@ H5PB__make_space(H5F_t *f, H5PB_t *page_buf, H5FD_mem_t inserted_type)
 
     /* Flush page if dirty */
     if(page_entry->is_dirty)
-        if(H5PB__write_entry(f, page_entry) < 0)
+        if(H5PB__write_entry(f_sh, page_entry) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
 
     /* Update statistics */
@@ -1478,7 +1474,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5PB__write_entry(H5F_t *f, H5PB_entry_t *page_entry)
+H5PB__write_entry(H5F_shared_t *f_sh, H5PB_entry_t *page_entry)
 {
     haddr_t eoa;                    /* Current EOA for the file */
     herr_t ret_value = SUCCEED;    /* Return value */
@@ -1486,11 +1482,11 @@ H5PB__write_entry(H5F_t *f, H5PB_entry_t *page_entry)
     FUNC_ENTER_STATIC
 
     /* Sanity check */
-    HDassert(f);
+    HDassert(f_sh);
     HDassert(page_entry);
 
     /* Retrieve the 'eoa' for the file */
-    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, (H5FD_mem_t)page_entry->type)))
+    if(HADDR_UNDEF == (eoa = H5F_shared_get_eoa(f_sh, (H5FD_mem_t)page_entry->type)))
         HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
 
     /* If the starting address of the page is larger than
@@ -1498,14 +1494,14 @@ H5PB__write_entry(H5F_t *f, H5PB_entry_t *page_entry)
      */
     if(page_entry->addr <= eoa) {
         H5FD_t *file;                   /* File driver I/O info */
-        size_t page_size = f->shared->page_buf->page_size;
+        size_t page_size = f_sh->page_buf->page_size;
 
         /* Adjust the page length if it exceeds the EOA */
         if((page_entry->addr + page_size) > eoa)
             page_size = (size_t)(eoa - page_entry->addr);
 
         /* Translate to file driver I/O info object */
-        file = f->shared->lf;
+        file = f_sh->lf;
 
         if(H5FD_write(file, (H5FD_mem_t)page_entry->type, page_entry->addr, page_size, page_entry->page_buf_ptr) < 0)
             HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
diff --git a/src/H5PBprivate.h b/src/H5PBprivate.h
index b94b845..82d010d 100644
--- a/src/H5PBprivate.h
+++ b/src/H5PBprivate.h
@@ -85,14 +85,14 @@ typedef struct H5PB_t {
 /***************************************/
 
 /* General routines */
-H5_DLL herr_t H5PB_create(H5F_t *file, size_t page_buffer_size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc);
-H5_DLL herr_t H5PB_flush(H5F_t *f);
-H5_DLL herr_t H5PB_dest(H5F_t *f);
-H5_DLL herr_t H5PB_add_new_page(H5F_t *f, H5FD_mem_t type, haddr_t page_addr);
+H5_DLL herr_t H5PB_create(H5F_shared_t *f_sh, size_t page_buffer_size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc);
+H5_DLL herr_t H5PB_flush(H5F_shared_t *f_sh);
+H5_DLL herr_t H5PB_dest(H5F_shared_t *f_sh);
+H5_DLL herr_t H5PB_add_new_page(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t page_addr);
 H5_DLL herr_t H5PB_update_entry(H5PB_t *page_buf, haddr_t addr, size_t size, const void *buf);
-H5_DLL herr_t H5PB_remove_entry(const H5F_t *f, haddr_t addr);
-H5_DLL herr_t H5PB_read(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/);
-H5_DLL herr_t H5PB_write(H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
+H5_DLL herr_t H5PB_remove_entry(const H5F_shared_t *f_sh, haddr_t addr);
+H5_DLL herr_t H5PB_read(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, void *buf/*out*/);
+H5_DLL herr_t H5PB_write(H5F_shared_t *f_sh, H5FD_mem_t type, haddr_t addr, size_t size, const void *buf);
 
 /* Statistics routines */
 H5_DLL herr_t H5PB_reset_stats(H5PB_t *page_buf);
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 8bb2b12..22252d3 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -30,22 +30,22 @@
 /***********/
 /* Headers */
 /***********/
-#include "H5private.h"          /* Generic Functions                    */
-#include "H5ACprivate.h"        /* Metadata cache                       */
-#include "H5Dprivate.h"         /* Datasets                             */
-#include "H5Eprivate.h"         /* Error handling                       */
-#include "H5Fprivate.h"         /* Files                                */
-#include "H5FDprivate.h"        /* File drivers                         */
-#include "H5Iprivate.h"         /* IDs                                  */
-#include "H5MMprivate.h"        /* Memory Management                    */
-#include "H5Ppkg.h"             /* Property lists                       */
-#include "H5VLprivate.h"        /* Virtual Object Layer                 */
+#include "H5private.h"          /* Generic Functions                        */
+#include "H5ACprivate.h"        /* Metadata cache                           */
+#include "H5Eprivate.h"         /* Error handling                           */
+#include "H5Fprivate.h"         /* Files                                    */
+#include "H5FDprivate.h"        /* File drivers                             */
+#include "H5Iprivate.h"         /* IDs                                      */
+#include "H5MMprivate.h"        /* Memory Management                        */
+#include "H5Ppkg.h"             /* Property lists                           */
+#include "H5VLprivate.h"        /* Virtual Object Layer                     */
+#include "H5VMprivate.h"        /* Vector Functions                         */
 
 /* Includes needed to set default file driver */
-#include "H5FDsec2.h"           /* POSIX unbuffered I/O                 */
-#include "H5FDstdio.h"          /* Standard C buffered I/O              */
+#include "H5FDsec2.h"           /* POSIX unbuffered I/O                     */
+#include "H5FDstdio.h"          /* Standard C buffered I/O                  */
 #ifdef H5_HAVE_WINDOWS
-#include "H5FDwindows.h"        /* Win32 I/O                            */
+#include "H5FDwindows.h"        /* Win32 I/O                                */
 #endif
 
 /* Includes needed to set default VOL connector */
@@ -111,7 +111,7 @@
 #define H5F_ACS_GARBG_COLCT_REF_DEF             0
 #define H5F_ACS_GARBG_COLCT_REF_ENC             H5P__encode_unsigned
 #define H5F_ACS_GARBG_COLCT_REF_DEC             H5P__decode_unsigned
-/* Definition for file driver ID & info*/
+/* Definition for file driver ID & info */
 #define H5F_ACS_FILE_DRV_SIZE                   sizeof(H5FD_driver_prop_t)
 #define H5F_ACS_FILE_DRV_DEF                    {H5_DEFAULT_VFD, NULL}
 #define H5F_ACS_FILE_DRV_CRT                    H5P__facc_file_driver_create
@@ -231,6 +231,24 @@
 #define H5F_ACS_COLL_MD_WRITE_FLAG_DEF    FALSE
 #define H5F_ACS_COLL_MD_WRITE_FLAG_ENC    H5P__encode_hbool_t
 #define H5F_ACS_COLL_MD_WRITE_FLAG_DEC    H5P__decode_hbool_t
+/* Definition for the file's MPI communicator */
+#define H5F_ACS_MPI_PARAMS_COMM_SIZE            sizeof(MPI_Comm)
+#define H5F_ACS_MPI_PARAMS_COMM_DEF             MPI_COMM_NULL
+#define H5F_ACS_MPI_PARAMS_COMM_SET             H5P__facc_mpi_comm_set
+#define H5F_ACS_MPI_PARAMS_COMM_GET             H5P__facc_mpi_comm_get
+#define H5F_ACS_MPI_PARAMS_COMM_DEL             H5P__facc_mpi_comm_del
+#define H5F_ACS_MPI_PARAMS_COMM_COPY            H5P__facc_mpi_comm_copy
+#define H5F_ACS_MPI_PARAMS_COMM_CMP             H5P__facc_mpi_comm_cmp
+#define H5F_ACS_MPI_PARAMS_COMM_CLOSE           H5P__facc_mpi_comm_close
+/* Definition for the file's MPI info */
+#define H5F_ACS_MPI_PARAMS_INFO_SIZE            sizeof(MPI_Info)
+#define H5F_ACS_MPI_PARAMS_INFO_DEF             MPI_INFO_NULL
+#define H5F_ACS_MPI_PARAMS_INFO_SET             H5P__facc_mpi_info_set
+#define H5F_ACS_MPI_PARAMS_INFO_GET             H5P__facc_mpi_info_get
+#define H5F_ACS_MPI_PARAMS_INFO_DEL             H5P__facc_mpi_info_del
+#define H5F_ACS_MPI_PARAMS_INFO_COPY            H5P__facc_mpi_info_copy
+#define H5F_ACS_MPI_PARAMS_INFO_CMP             H5P__facc_mpi_info_cmp
+#define H5F_ACS_MPI_PARAMS_INFO_CLOSE           H5P__facc_mpi_info_close
 #endif /* H5_HAVE_PARALLEL */
 /* Definitions for the initial metadata cache image configuration */
 #define H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_SIZE sizeof(H5AC_cache_image_config_t)
@@ -334,6 +352,24 @@ static herr_t H5P__facc_vol_copy(const char *name, size_t size, void *value);
 static int H5P__facc_vol_cmp(const void *value1, const void *value2, size_t size);
 static herr_t H5P__facc_vol_close(const char *name, size_t size, void *value);
 
+#ifdef H5_HAVE_PARALLEL
+/* MPI communicator callbacks */
+static herr_t H5P__facc_mpi_comm_set(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_comm_get(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_comm_del(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_comm_copy(const char *name, size_t size, void *value);
+static int    H5P__facc_mpi_comm_cmp(const void *value1, const void *value2, size_t size);
+static herr_t H5P__facc_mpi_comm_close(const char *name, size_t size, void *value);
+
+/* MPI info callbacks */
+static herr_t H5P__facc_mpi_info_set(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_info_get(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_info_del(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mpi_info_copy(const char *name, size_t size, void *value);
+static int    H5P__facc_mpi_info_cmp(const void *value1, const void *value2, size_t size);
+static herr_t H5P__facc_mpi_info_close(const char *name, size_t size, void *value);
+#endif /* H5_HAVE_PARALLEL */
+
 
 /*********************/
 /* Package Variables */
@@ -404,6 +440,8 @@ static const hbool_t H5F_def_evict_on_close_flag_g = H5F_ACS_EVICT_ON_CLOSE_FLAG
 #ifdef H5_HAVE_PARALLEL
 static const H5P_coll_md_read_flag_t H5F_def_coll_md_read_flag_g = H5F_ACS_COLL_MD_READ_FLAG_DEF;  /* Default setting for the collective metedata read flag */
 static const hbool_t H5F_def_coll_md_write_flag_g = H5F_ACS_COLL_MD_WRITE_FLAG_DEF;  /* Default setting for the collective metedata write flag */
+static const MPI_Comm H5F_def_mpi_params_comm_g = H5F_ACS_MPI_PARAMS_COMM_DEF;  /* Default MPI communicator */
+static const MPI_Info H5F_def_mpi_params_info_g = H5F_ACS_MPI_PARAMS_INFO_DEF;  /* Default MPI info struct */
 #endif /* H5_HAVE_PARALLEL */
 static const H5AC_cache_image_config_t H5F_def_mdc_initCacheImageCfg_g = H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_DEF;  /* Default metadata cache image settings */
 static const size_t H5F_def_page_buf_size_g = H5F_ACS_PAGE_BUFFER_SIZE_DEF;      /* Default page buffer size */
@@ -621,6 +659,19 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, H5F_ACS_COLL_MD_WRITE_FLAG_ENC, H5F_ACS_COLL_MD_WRITE_FLAG_DEC,
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
+    /* Register the MPI communicator */
+    if(H5P__register_real(pclass, H5F_ACS_MPI_PARAMS_COMM_NAME, H5F_ACS_MPI_PARAMS_COMM_SIZE, &H5F_def_mpi_params_comm_g,
+            NULL, H5F_ACS_MPI_PARAMS_COMM_SET, H5F_ACS_MPI_PARAMS_COMM_GET, NULL, NULL,
+            H5F_ACS_MPI_PARAMS_COMM_DEL, H5F_ACS_MPI_PARAMS_COMM_COPY, H5F_ACS_MPI_PARAMS_COMM_CMP, H5F_ACS_MPI_PARAMS_COMM_CLOSE) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
+    /* Register the MPI info struct */
+    if(H5P__register_real(pclass, H5F_ACS_MPI_PARAMS_INFO_NAME, H5F_ACS_MPI_PARAMS_INFO_SIZE, &H5F_def_mpi_params_info_g,
+            NULL, H5F_ACS_MPI_PARAMS_INFO_SET, H5F_ACS_MPI_PARAMS_INFO_GET, NULL, NULL,
+            H5F_ACS_MPI_PARAMS_INFO_DEL, H5F_ACS_MPI_PARAMS_INFO_COPY, H5F_ACS_MPI_PARAMS_INFO_CMP, H5F_ACS_MPI_PARAMS_INFO_CLOSE) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 #endif /* H5_HAVE_PARALLEL */
 
     /* Register the initial metadata cache image configuration */
@@ -634,11 +685,13 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_SIZE_ENC, H5F_ACS_PAGE_BUFFER_SIZE_DEC,
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
     /* Register the size of the page buffer minimum metadata size */
     if(H5P__register_real(pclass, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_SIZE, &H5F_def_page_buf_min_meta_perc_g,
             NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_ENC, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEC,
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
     /* Register the size of the page buffer minimum raw data size */
     if(H5P__register_real(pclass, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_SIZE, &H5F_def_page_buf_min_raw_perc_g,
             NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_ENC, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEC,
@@ -4738,6 +4791,468 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5Pget_mpi_params
+ *
+ * Purpose:     Gets the MPI communicator and info stored in the fapl.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Dana Robinson
+ *              August 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_mpi_params(hid_t plist_id, MPI_Comm *comm, MPI_Info *info)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value = SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*Mc*Mi", plist_id, comm, info);
+
+    /* Make sure that the property list is a fapl */
+    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTREGISTER, FAIL, "property list is not a file access plist")
+
+    /* Get the plist structure */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(plist_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get the properties */
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, comm) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get MPI communicator from plist")
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get MPI info from plist")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_mpi_params() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_mpi_params
+ *
+ * Purpose:     Set the MPI communicator and info
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Dana Robinson
+ *              August 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_mpi_params(hid_t plist_id, MPI_Comm comm, MPI_Info info)
+{
+    H5P_genplist_t  *plist;                 /* Property list pointer */
+    herr_t          ret_value = SUCCEED;    /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "iMcMi", plist_id, comm, info);
+
+    /* Make sure the MPI communicator is valid */
+    if(MPI_COMM_NULL == comm)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "not a valid argument")
+
+    /* Make sure that the property list is a fapl */
+    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTREGISTER, FAIL, "property list is not a file access plist")
+
+    /* Get the plist structure */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(plist_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Set values */
+    if(H5P_set(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, &comm) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI communicator")
+    if(H5P_set(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI info object")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_mpi_params() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_comm_set
+ *
+ * Purpose:     Copies an MPI comminicator property when it's set for a property list
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_comm_set(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+    size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Comm    *comm = (MPI_Comm *)value;
+    MPI_Comm    comm_tmp = MPI_COMM_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI communicator */
+    if(H5_mpi_comm_dup(*comm, &comm_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI communicator")
+
+done:
+    /* Copy the communicator to the in/out parameter */
+    if(ret_value != SUCCEED)
+        *comm = MPI_COMM_NULL;
+    else
+        *comm = comm_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_set() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_comm_get
+ *
+ * Purpose:     Copies an MPI comminicator property when it's retrieved from a property list
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_comm_get(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+    size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Comm    *comm = (MPI_Comm *)value;
+    MPI_Comm    comm_tmp = MPI_COMM_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI communicator */
+    if(H5_mpi_comm_dup(*comm, &comm_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI communicator")
+
+done:
+    /* Copy the communicator to the out parameter */
+    if(ret_value != SUCCEED)
+        *comm = MPI_COMM_NULL;
+    else
+        *comm = comm_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_get() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_comm_del
+ *
+ * Purpose:     Frees an MPI communicator property
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_comm_del(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Comm    *comm = (MPI_Comm *)value;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Free the MPI communicator */
+    if(H5_mpi_comm_free(comm) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI communicator")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_del() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_comm_copy
+ *
+ * Purpose:     Copy callback for the MPI communicator property.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_comm_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Comm    *comm = (MPI_Comm *)value;
+    MPI_Comm    comm_tmp = MPI_COMM_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI communicator */
+    if(H5_mpi_comm_dup(*comm, &comm_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI communicator")
+
+done:
+    /* Copy the communicator to the in/out parameter */
+    if(ret_value != SUCCEED)
+        *comm = MPI_COMM_NULL;
+    else
+        *comm = comm_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_copy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P__facc_mpi_comm_cmp
+ *
+ * Purpose:        Callback routine which is called whenever the MPI
+ *                 communicator property in the file access property list
+ *                 is compared.
+ *
+ * Return:         positive if VALUE1 is greater than VALUE2, negative if
+ *                 VALUE2 is greater than VALUE1 and zero if VALUE1 and
+ *                 VALUE2 are equal.
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5P__facc_mpi_comm_cmp(const void *_comm1, const void *_comm2, size_t H5_ATTR_UNUSED size)
+{
+    const MPI_Comm  *comm1 = (const MPI_Comm *)_comm1;
+    const MPI_Comm  *comm2 = (const MPI_Comm *)_comm2;
+    int         ret_value = 0;
+
+    FUNC_ENTER_STATIC
+
+    /* Compare the MPI communicators */
+    if(H5_mpi_comm_cmp(*comm1, *comm2, &ret_value) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, 0, "unable to compare MPI communicator")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_cmp() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_comm_close
+ *
+ * Purpose:     Close callback for the MPI communicator property.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_comm_close(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Comm    *comm = (MPI_Comm *)value;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Free the MPI communicator */
+    if(H5_mpi_comm_free(comm) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI communicator")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_comm_close() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_info_set
+ *
+ * Purpose:     Copies an MPI info object property when it's set for a property list
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_info_set(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+    size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Info    *info = (MPI_Info *)value;
+    MPI_Info    info_tmp = MPI_INFO_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI info object */
+    if(H5_mpi_info_dup(*info, &info_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI info object")
+
+done:
+    /* Copy the info object to the in/out parameter */
+    if(ret_value != SUCCEED)
+        *info = MPI_INFO_NULL;
+    else
+        *info = info_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_set() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_info_get
+ *
+ * Purpose:     Copies an MPI comminicator property when it's retrieved from a property list
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_info_get(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+    size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Info    *info = (MPI_Info *)value;
+    MPI_Info    info_tmp = MPI_INFO_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI communicator */
+    if(H5_mpi_info_dup(*info, &info_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI info object")
+
+done:
+    /* Copy the info object to the out parameter */
+    if(ret_value != SUCCEED)
+        *info = MPI_INFO_NULL;
+    else
+        *info = info_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_get() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_info_del
+ *
+ * Purpose:     Frees an MPI info object property
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_info_del(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Info    *info = (MPI_Info *)value;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Free the MPI info object */
+    if(H5_mpi_info_free(info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI info object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_del() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_info_copy
+ *
+ * Purpose:     Copy callback for the MPI info object property.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_info_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Info    *info = (MPI_Info *)value;
+    MPI_Info    info_tmp = MPI_INFO_NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Make a copy of the MPI info object */
+    if(H5_mpi_info_dup(*info, &info_tmp) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "unable to duplicate MPI info object")
+
+done:
+    /* Copy the info object to the in/out parameter */
+    if(ret_value != SUCCEED)
+        *info = MPI_INFO_NULL;
+    else
+        *info = info_tmp;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_copy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P__facc_mpi_info_cmp
+ *
+ * Purpose:        Callback routine which is called whenever the MPI
+ *                 info object property in the file access property list
+ *                 is compared.
+ *
+ * Return:         positive if VALUE1 is greater than VALUE2, negative if
+ *                 VALUE2 is greater than VALUE1 and zero if VALUE1 and
+ *                 VALUE2 are equal.
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5P__facc_mpi_info_cmp(const void *_info1, const void *_info2, size_t H5_ATTR_UNUSED size)
+{
+    const MPI_Info  *info1 = (const MPI_Info *)_info1;
+    const MPI_Info  *info2 = (const MPI_Info *)_info2;
+    int         ret_value = 0;
+
+    FUNC_ENTER_STATIC
+
+    /* Compare the MPI info objects */
+    if(H5_mpi_info_cmp(*info1, *info2, &ret_value) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, 0, "unable to compare MPI info objects")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_cmp() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__facc_mpi_info_close
+ *
+ * Purpose:     Close callback for the MPI info object property.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_mpi_info_close(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+{
+    MPI_Info    *info = (MPI_Info *)value;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Free the MPI info object */
+    if(H5_mpi_info_free(info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "unable to free MPI info object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__facc_mpi_info_close() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Pget_coll_metadata_write
  *
  * Purpose:    Gets information about collective metadata write mode.
@@ -5305,4 +5820,3 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P__facc_vol_close() */
 
-
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index 43e477a..9f26b8b 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -381,6 +381,8 @@ H5_DLL herr_t H5Pset_all_coll_metadata_ops(hid_t plist_id, hbool_t is_collective
 H5_DLL herr_t H5Pget_all_coll_metadata_ops(hid_t plist_id, hbool_t *is_collective);
 H5_DLL herr_t H5Pset_coll_metadata_write(hid_t plist_id, hbool_t is_collective);
 H5_DLL herr_t H5Pget_coll_metadata_write(hid_t plist_id, hbool_t *is_collective);
+H5_DLL herr_t H5Pget_mpi_params(hid_t fapl_id, MPI_Comm *comm, MPI_Info *info);
+H5_DLL herr_t H5Pset_mpi_params(hid_t fapl_id, MPI_Comm comm, MPI_Info info);
 #endif /* H5_HAVE_PARALLEL */
 H5_DLL herr_t H5Pset_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr);
 H5_DLL herr_t H5Pget_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr /*out*/);
diff --git a/src/H5VLnative.h b/src/H5VLnative.h
index 1a3007a..a8d5720 100644
--- a/src/H5VLnative.h
+++ b/src/H5VLnative.h
@@ -36,8 +36,11 @@ typedef int H5VL_native_dataset_optional_t;
 #define H5VL_NATIVE_DATASET_FORMAT_CONVERT          0   /* H5Dformat_convert (internal) */
 #define H5VL_NATIVE_DATASET_GET_CHUNK_INDEX_TYPE    1   /* H5Dget_chunk_index_type      */
 #define H5VL_NATIVE_DATASET_GET_CHUNK_STORAGE_SIZE  2   /* H5Dget_chunk_storage_size    */
-#define H5VL_NATIVE_DATASET_CHUNK_READ              3   /* H5Dchunk_read                */
-#define H5VL_NATIVE_DATASET_CHUNK_WRITE             4   /* H5Dchunk_write               */
+#define H5VL_NATIVE_DATASET_GET_NUM_CHUNKS          3   /* H5Dget_num_chunks            */
+#define H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_IDX   4   /* H5Dget_chunk_info            */
+#define H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_COORD 5   /* H5Dget_chunk_info_by_coord   */
+#define H5VL_NATIVE_DATASET_CHUNK_READ              6   /* H5Dchunk_read                */
+#define H5VL_NATIVE_DATASET_CHUNK_WRITE             7   /* H5Dchunk_write               */
 
 /* Typedef and values for native VOL connector file optional VOL operations */
 typedef int H5VL_native_file_optional_t;
diff --git a/src/H5VLnative_dataset.c b/src/H5VLnative_dataset.c
index 1e3d263..676d859 100644
--- a/src/H5VLnative_dataset.c
+++ b/src/H5VLnative_dataset.c
@@ -339,7 +339,7 @@ H5VL__native_dataset_specific(void *obj, H5VL_dataset_specific_t specific_type,
     switch(specific_type) {
         /* H5Dspecific_space */
         case H5VL_DATASET_SET_EXTENT:
-            {
+            { /* H5Dset_extent (H5Dextend - deprecated) */
                 const hsize_t *size = HDva_arg(arguments, const hsize_t *); 
 
                 if(H5D__set_extent(dset, size) < 0)
@@ -348,7 +348,7 @@ H5VL__native_dataset_specific(void *obj, H5VL_dataset_specific_t specific_type,
             }
 
         case H5VL_DATASET_FLUSH:
-            {
+            { /* H5Dflush */
                 hid_t dset_id = HDva_arg(arguments, hid_t);
 
                 /* Flush the dataset */
@@ -359,7 +359,7 @@ H5VL__native_dataset_specific(void *obj, H5VL_dataset_specific_t specific_type,
             }
 
         case H5VL_DATASET_REFRESH:
-            {
+            { /* H5Drefresh */
                 hid_t dset_id = HDva_arg(arguments, hid_t);
 
                 /* Refresh the dataset */
@@ -399,7 +399,7 @@ H5VL__native_dataset_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
 
     switch(optional_type) {
         case H5VL_NATIVE_DATASET_FORMAT_CONVERT:
-            {
+            {   /* H5Dformat_convert */
                 dset = (H5D_t *)obj;
 
                 switch(dset->shared->layout.type) {
@@ -434,7 +434,7 @@ H5VL__native_dataset_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
             }
 
         case H5VL_NATIVE_DATASET_GET_CHUNK_INDEX_TYPE:
-            {
+            {   /* H5Dget_chunk_index_type */
                 H5D_chunk_index_t *idx_type = HDva_arg(arguments, H5D_chunk_index_t *);
 
                 dset = (H5D_t *)obj;
@@ -450,7 +450,7 @@ H5VL__native_dataset_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
             }
 
         case H5VL_NATIVE_DATASET_GET_CHUNK_STORAGE_SIZE:
-            {
+            {   /* H5Dget_chunk_storage_size */
                 hsize_t *offset = HDva_arg(arguments, hsize_t *);
                 hsize_t *chunk_nbytes = HDva_arg(arguments, hsize_t *);
 
@@ -467,8 +467,91 @@ H5VL__native_dataset_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
                 break;
             }
 
+        case H5VL_NATIVE_DATASET_GET_NUM_CHUNKS:
+            {   /* H5Dget_num_chunks */
+                const H5S_t *space    = NULL;
+                hid_t        space_id = HDva_arg(arguments, hid_t);
+                hsize_t     *nchunks  = HDva_arg(arguments, hsize_t *);
+
+                dset = (H5D_t *)obj;
+                HDassert(dset);
+                HDassert(dset->shared);
+                HDassert(dset->shared->space);
+
+                /* When default dataspace is given, use the dataset's dataspace */
+                if(space_id == H5S_ALL)
+                    space = dset->shared->space;
+                else /*  otherwise, use the given space ID */
+                    if(NULL == (space = (const H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
+                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a valid dataspace ID")
+
+                /* Make sure the dataset is chunked */
+                if(H5D_CHUNKED != dset->shared->layout.type)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a chunked dataset")
+
+                /* Call private function */
+                if(H5D__get_num_chunks(dset, space, nchunks) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get number of chunks")
+
+                break;
+            }
+
+        case H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_IDX:
+            {   /* H5Dget_chunk_info */
+                const H5S_t *space = NULL;
+                hid_t        space_id    = HDva_arg(arguments, hid_t);
+                hsize_t      chk_index   = HDva_arg(arguments, hsize_t);
+                hsize_t     *offset = HDva_arg(arguments, hsize_t *);
+                unsigned    *filter_mask = HDva_arg(arguments, unsigned *);
+                haddr_t     *addr        = HDva_arg(arguments, haddr_t *);
+                hsize_t     *size        = HDva_arg(arguments, hsize_t *);
+
+                dset = (H5D_t *)obj;
+                HDassert(dset);
+                HDassert(dset->shared);
+                HDassert(dset->shared->space);
+
+                /* When default dataspace is given, use the dataset's dataspace */
+                if(space_id == H5S_ALL)
+                    space = dset->shared->space;
+                else /*  otherwise, use the given space ID */
+                    if(NULL == (space = (const H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
+                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a valid dataspace ID")
+
+                /* Make sure the dataset is chunked */
+                if(H5D_CHUNKED != dset->shared->layout.type)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a chunked dataset")
+
+                /* Call private function */
+                if(H5D__get_chunk_info(dset, space, chk_index, offset, filter_mask, addr, size) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get chunk info by index")
+                break;
+            }
+
+        case H5VL_NATIVE_DATASET_GET_CHUNK_INFO_BY_COORD:
+            {   /* H5Dget_chunk_info_by_coord */
+                hsize_t  *offset      = HDva_arg(arguments, hsize_t *);
+                unsigned *filter_mask = HDva_arg(arguments, unsigned *);
+                haddr_t  *addr        = HDva_arg(arguments, haddr_t *);
+                hsize_t  *size        = HDva_arg(arguments, hsize_t *);
+
+                dset = (H5D_t *)obj;
+                HDassert(dset);
+                HDassert(dset->shared);
+
+                /* Make sure the dataset is chunked */
+                if(H5D_CHUNKED != dset->shared->layout.type)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a chunked dataset")
+
+                /* Call private function */
+                if(H5D__get_chunk_info_by_coord(dset, offset, filter_mask, addr, size) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get chunk info by its logical coordinates")
+
+                break;
+            }
+
         case H5VL_NATIVE_DATASET_CHUNK_READ:
-            {
+            {   /* H5Dread_chunk */
                 const       hsize_t *offset     = HDva_arg(arguments, hsize_t *);
                 uint32_t   *filters             = HDva_arg(arguments, uint32_t *);
                 void       *buf                 = HDva_arg(arguments, void *);
@@ -496,7 +579,7 @@ H5VL__native_dataset_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
             }
 
         case H5VL_NATIVE_DATASET_CHUNK_WRITE:
-            {
+            {   /* H5Dwrite_chunk */
                 uint32_t        filters             = HDva_arg(arguments, uint32_t);
                 const  hsize_t *offset              = HDva_arg(arguments, const hsize_t *);
                 uint32_t        data_size_32        = HDva_arg(arguments, uint32_t);
diff --git a/src/H5mpi.c b/src/H5mpi.c
index ea6b33f..d48790b 100644
--- a/src/H5mpi.c
+++ b/src/H5mpi.c
@@ -16,14 +16,10 @@
  *
  */
 
-
 #include "H5private.h"          /* Generic Functions                        */
-#include "H5CXprivate.h"        /* API Contexts                             */
 #include "H5Eprivate.h"         /* Error handling                           */
-#include "H5Fprivate.h"         /* File access                              */
-#include "H5FDprivate.h"        /* File drivers                             */
-#include "H5FDmpi.h"            /* Common MPI file driver                   */
-#include "H5Pprivate.h"         /* Property lists                           */
+#include "H5MMprivate.h"        /* Memory Management                        */
+
 
 #ifdef H5_HAVE_PARALLEL
 
@@ -32,6 +28,9 @@
  *
  * Purpose:     Duplicate an MPI communicator.
  *
+ *              Does not duplicate MPI_COMM_NULL. Instead, comm_new will
+ *              be set to MPI_COMM_NULL directly.
+ *
  *              The new communicator is returned via the comm_new pointer.
  *
  * Return:      SUCCEED/FAIL
@@ -50,19 +49,26 @@ H5_mpi_comm_dup(MPI_Comm comm, MPI_Comm *comm_new)
     /* Check arguments */
     if (!comm_new)
         HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "comm_new cannot be NULL")
-    if (MPI_COMM_NULL == comm)
-        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "can't duplicate MPI_COMM_NULL")
 
-    /* Duplicate the MPI communicator */
-    if (MPI_SUCCESS != (mpi_code = MPI_Comm_dup(comm, &comm_dup)))
-        HMPI_GOTO_ERROR(FAIL, "MPI_Comm_dup failed", mpi_code)
+    /* Handle MPI_COMM_NULL separately */
+    if (MPI_COMM_NULL == comm) {
+        /* Don't duplicate MPI_COMM_NULL since that's an error in MPI */
+        comm_dup = MPI_COMM_NULL;
+    }
+    else {
 
-    /* Set MPI_ERRORS_RETURN on comm_dup so that MPI failures are not fatal, 
-     * and return codes can be checked and handled.
-     */
-    if (MPI_SUCCESS != (mpi_code = MPI_Comm_set_errhandler(comm_dup, MPI_ERRORS_RETURN)))
-        HMPI_GOTO_ERROR(FAIL, "MPI_Errhandler_set failed", mpi_code)
+        /* Duplicate the MPI communicator */
+        if (MPI_SUCCESS != (mpi_code = MPI_Comm_dup(comm, &comm_dup)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Comm_dup failed", mpi_code)
+
+        /* Set MPI_ERRORS_RETURN on comm_dup so that MPI failures are not fatal,
+         * and return codes can be checked and handled.
+         */
+        if (MPI_SUCCESS != (mpi_code = MPI_Comm_set_errhandler(comm_dup, MPI_ERRORS_RETURN)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Errhandler_set failed", mpi_code)
  
+    }
+
     /* Copy the new communicator to the return argument */
     *comm_new = comm_dup;
 
@@ -108,7 +114,7 @@ H5_mpi_info_dup(MPI_Info info, MPI_Info *info_new)
     /* Duplicate the MPI info */
     if (info == MPI_INFO_NULL) {
         /* Don't duplicate MPI_INFO_NULL. Just copy it. */
-        info_dup = info;
+        info_dup = MPI_INFO_NULL;
     }
     else {
         /* Duplicate the info */
@@ -194,5 +200,197 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* End H5_mpi_info_free() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5_mpi_comm_cmp
+ *
+ * Purpose:     Compares two MPI communicators.
+ *
+ *              Note that passing MPI_COMM_NULL to this function will not
+ *              throw errors, unlike MPI_Comm_compare().
+ *
+ *              We consider MPI communicators to be the "same" when the
+ *              groups are identical. We don't care about the context
+ *              since that will always be different as we call MPI_Comm_dup
+ *              when we store the communicator in the fapl.
+ *
+ *              The out parameter is a value like strcmp. The value is
+ *              undefined when the return value is FAIL.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result)
+{
+    int         mpi_code;
+    int         mpi_result = MPI_IDENT;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Check arguments */
+    if (!result)
+        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "result cannot be NULL")
+
+    /* Set out parameter to something reasonable in case something goes wrong */
+    *result = 0;
+
+    /* Can't pass MPI_COMM_NULL to MPI_Comm_compare() so we have to handle
+     * it in special cases.
+     *
+     * MPI_Comm can either be an integer type or a pointer. We cast them
+     * to intptr_t so we can compare them with < and > when needed.
+     */
+    if (MPI_COMM_NULL == comm1 && MPI_COMM_NULL == comm2) {
+        /* Special case of both communicators being MPI_COMM_NULL */
+        *result = 0;
+    }
+    else if (MPI_COMM_NULL == comm1 || MPI_COMM_NULL == comm2) {
+
+        /* Special case of one communicator being MPI_COMM_NULL */
+        *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
+    }
+    else {
+
+        /* Normal communicator compare */
+
+        /* Compare the MPI communicators */
+        if (MPI_SUCCESS != (mpi_code = MPI_Comm_compare(comm1, comm2, &mpi_result)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Comm_compare failed", mpi_code)
+
+        /* Set the result */
+        if (MPI_IDENT == mpi_result || MPI_CONGRUENT == mpi_result)
+            *result = 0;
+        else
+            *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5_mpi_comm_cmp() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5_mpi_info_cmp
+ *
+ * Purpose:     Compares two MPI info objects.
+ *
+ *              For our purposes, two mpi info objects are the "same" if
+ *              they contain the same key-value pairs or are both
+ *              MPI_INFO_NULL.
+ *
+ *              The out parameter is a value like strcmp. The value is
+ *              undefined when the return value is FAIL.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5_mpi_info_cmp(MPI_Info info1, MPI_Info info2, int *result)
+{
+    hbool_t     same = FALSE;
+    char        *key = NULL;
+    char        *value1 = NULL;
+    char        *value2 = NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Check arguments */
+    if (!result)
+        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "result cannot be NULL")
+
+    /* Check for MPI_INFO_NULL */
+    if (MPI_INFO_NULL == info1 && MPI_INFO_NULL == info2) {
+        /* Special case of both info objects being MPI_INFO_NULL */
+        same = TRUE;
+    }
+    else if (MPI_INFO_NULL == info1 || MPI_INFO_NULL == info2) {
+
+        /* Special case of one info object being MPI_INFO_NULL */
+        same = FALSE;
+    }
+    else {
+        int         mpi_code;
+        int         nkeys_1;
+        int         nkeys_2;
+
+        /* Check if the number of keys is the same */
+        if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nkeys(info1, &nkeys_1)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nkeys failed", mpi_code)
+        if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nkeys(info2, &nkeys_2)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nkeys failed", mpi_code)
+
+        if (nkeys_1 != nkeys_2)
+            same = FALSE;
+        else if (0 == nkeys_1 && 0 == nkeys_2)
+            same = TRUE;
+        else {
+            int i;
+            int flag1 = -1;
+            int flag2 = -1;
+
+            /* Allocate buffers for iteration */
+            if (NULL == (key = (char *)H5MM_malloc(MPI_MAX_INFO_KEY * sizeof(char))))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+            if (NULL == (value1 = (char *)H5MM_malloc(MPI_MAX_INFO_VAL * sizeof(char))))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+            if (NULL == (value2 = (char *)H5MM_malloc(MPI_MAX_INFO_VAL * sizeof(char))))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+            /* Iterate over the keys, comparing them */
+            for (i = 0; i < nkeys_1; i++) {
+
+                same = TRUE;
+
+                /* Memset the buffers to zero */
+                HDmemset(key, 0, MPI_MAX_INFO_KEY);
+                HDmemset(value1, 0, MPI_MAX_INFO_VAL);
+                HDmemset(value2, 0, MPI_MAX_INFO_VAL);
+
+                /* Get the nth key */
+                if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nthkey(info1, i, key)))
+                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nthkey failed", mpi_code)
+
+                /* Get the values */
+                if (MPI_SUCCESS != (mpi_code = MPI_Info_get(info1, key, MPI_MAX_INFO_VAL, value1, &flag1)))
+                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get failed", mpi_code)
+                if (MPI_SUCCESS != (mpi_code = MPI_Info_get(info2, key, MPI_MAX_INFO_VAL, value2, &flag2)))
+                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get failed", mpi_code)
+
+                /* Compare values and flags */
+                if (!flag1 || !flag2 || HDmemcmp(value1, value2, MPI_MAX_INFO_VAL)) {
+                    same = FALSE;
+                    break;
+                }
+
+            } /* end for */
+        } /* end else */
+    } /* end else */
+
+    /* Set the output value
+     *
+     * MPI_Info can either be an integer type or a pointer. We cast them
+     * to intptr_t so we can compare them with < and > when needed.
+     */
+    if (same)
+        *result = 0;
+    else
+        *result = (intptr_t)info1 < (intptr_t)info2 ? -1 : 1;
+
+done:
+    if (key)
+        H5MM_xfree(key);
+    if (value1)
+        H5MM_xfree(value1);
+    if (value2)
+        H5MM_xfree(value2);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5_mpi_info_cmp() */
+
 #endif /* H5_HAVE_PARALLEL */
 
diff --git a/src/H5private.h b/src/H5private.h
index 18b52a0..bb2a2eb 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -2674,6 +2674,8 @@ H5_DLL herr_t   H5_mpi_comm_dup(MPI_Comm comm, MPI_Comm *comm_new);
 H5_DLL herr_t   H5_mpi_info_dup(MPI_Info info, MPI_Info *info_new);
 H5_DLL herr_t   H5_mpi_comm_free(MPI_Comm *comm);
 H5_DLL herr_t   H5_mpi_info_free(MPI_Info *info);
+H5_DLL herr_t   H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result);
+H5_DLL herr_t   H5_mpi_info_cmp(MPI_Info info1, MPI_Info info2, int *result);
 #endif /* H5_HAVE_PARALLEL */
 
 /* Functions for debugging */
diff --git a/src/H5system.c b/src/H5system.c
index 1d47d13..384360d 100644
--- a/src/H5system.c
+++ b/src/H5system.c
@@ -631,7 +631,7 @@ Pflock(int fd, int operation) {
     flk.l_pid = 0;              /* not used with set */
 
     /* Lock or unlock */
-    if(HDfcntl(fd, F_SETLK, flk) < 0)
+    if(HDfcntl(fd, F_SETLK, &flk) < 0)
         return -1;
 
     return 0;
diff --git a/src/Makefile.am b/src/Makefile.am
index 1e1273c..ccee69b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -62,9 +62,8 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5Fsfile.c H5Fspace.c H5Fsuper.c H5Fsuper_cache.c H5Ftest.c \
         H5FA.c H5FAcache.c H5FAdbg.c H5FAdblock.c H5FAdblkpage.c H5FAhdr.c \
         H5FAint.c H5FAstat.c H5FAtest.c \
-        H5FD.c H5FDcore.c  \
-        H5FDfamily.c H5FDhdfs.c H5FDint.c H5FDlog.c H5FDs3comms.c \
-        H5FDmulti.c H5FDros3.c H5FDsec2.c H5FDspace.c H5FDstdio.c H5FDtest.c \
+        H5FD.c H5FDcore.c H5FDfamily.c H5FDhdfs.c H5FDint.c H5FDlog.c \
+        H5FDmulti.c H5FDsec2.c H5FDspace.c H5FDstdio.c H5FDtest.c \
         H5FL.c H5FO.c H5FS.c H5FScache.c H5FSdbg.c H5FSint.c H5FSsection.c \
         H5FSstat.c H5FStest.c \
         H5G.c H5Gbtree2.c H5Gcache.c \
@@ -134,6 +133,11 @@ if DIRECT_VFD_CONDITIONAL
     libhdf5_la_SOURCES += H5FDdirect.c
 endif
 
+# Only compile the read-only S3 VFD if necessary
+if ROS3_VFD_CONDITIONAL
+    libhdf5_la_SOURCES += H5FDros3.c H5FDs3comms.c
+endif
+
 # Public headers
 include_HEADERS = hdf5.h H5api_adpt.h H5overflow.h H5pubconf.h H5public.h H5version.h \
         H5Apublic.h H5ACpublic.h \