Merge branch 'develop' of https://bitbucket.hdfgroup.org/scm/~songyulu/hdf5_ray into HDFFV-10658-performance-drop-from-1-8

19 files changed, 334 insertions, 122 deletions

diff --git a/src/H5Aint.c b/src/H5Aint.c
index 88a4780..d8ba92a 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -108,6 +108,7 @@ static herr_t H5A__iterate_common(hid_t loc_id, H5_index_t idx_type,
 const unsigned H5O_attr_ver_bounds[] = {
     H5O_ATTR_VERSION_1,         /* H5F_LIBVER_EARLIEST */
     H5O_ATTR_VERSION_3,         /* H5F_LIBVER_V18 */
+    H5O_ATTR_VERSION_3,         /* H5F_LIBVER_V110 */
     H5O_ATTR_VERSION_LATEST     /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5CX.c b/src/H5CX.c
index d9334d0..c78d508 100644
--- a/src/H5CX.c
+++ b/src/H5CX.c
@@ -193,6 +193,10 @@ typedef struct H5CX_t {
     hid_t dapl_id;              /* DAPL ID for API operation */
     H5P_genplist_t *dapl;       /* Dataset Access Property List */
 
+    /* FAPL */
+    hid_t fapl_id;              /* FAPL ID for API operation */
+    H5P_genplist_t *fapl;       /* File Access Property List */
+
     /* Internal: Object tagging info */
     haddr_t tag;                /* Current object's tag (ohdr chunk #0 address) */
 
@@ -288,6 +292,12 @@ typedef struct H5CX_t {
     char *vds_prefix;
     hbool_t vds_prefix_valid;
 
+    /* Cached FAPL properties */
+    H5F_libver_t low_bound;     /* low_bound property for H5Pset_libver_bounds() */
+    hbool_t low_bound_valid;    /* Whether low_bound property is valid */
+    H5F_libver_t high_bound;    /* high_bound property for H5Pset_libver_bounds */
+    hbool_t high_bound_valid;   /* Whether high_bound property is valid */
+
     /* Cached VOL settings */
     H5VL_connector_prop_t vol_connector_prop;  /* Property for VOL connector ID & info */
     hbool_t vol_connector_prop_valid; /* Whether property for VOL connector ID & info is valid */
@@ -355,6 +365,13 @@ typedef struct H5CX_dapl_cache_t {
     char *vds_prefix;
 } H5CX_dapl_cache_t;
 
+/* Typedef for cached default file access property list information */
+/* (Same as the cached DXPL struct, above, except for the default DCPL) */
+typedef struct H5CX_fapl_cache_t {
+    H5F_libver_t low_bound;     /* low_bound property for H5Pset_libver_bounds() */
+    H5F_libver_t high_bound;    /* high_bound property for H5Pset_libver_bounds */
+} H5CX_fapl_cache_t;
+
 /********************/
 /* Local Prototypes */
 /********************/
@@ -393,6 +410,9 @@ static H5CX_dcpl_cache_t H5CX_def_dcpl_cache;
 /* Define a "default" dataset access property list cache structure to use for default DAPLs */
 static H5CX_dapl_cache_t H5CX_def_dapl_cache;
 
+/* Define a "default" file access property list cache structure to use for default FAPLs */
+static H5CX_fapl_cache_t H5CX_def_fapl_cache;
+
 /* Declare a static free list to manage H5CX_node_t structs */
 H5FL_DEFINE_STATIC(H5CX_node_t);
 
@@ -418,6 +438,7 @@ H5CX__init_package(void)
     H5P_genplist_t *la_plist;           /* Link access property list */
     H5P_genplist_t *dc_plist;           /* Dataset creation property list */
     H5P_genplist_t *da_plist;           /* Dataset access property list */
+    H5P_genplist_t *fa_plist;           /* File access property list */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -531,7 +552,6 @@ H5CX__init_package(void)
     if(H5P_get(dc_plist, H5D_CRT_MIN_DSET_HDR_SIZE_NAME, &H5CX_def_dcpl_cache.do_min_dset_ohdr) < 0)
         HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "Can't retrieve dataset minimize flag")
 
-
     /* Reset the "default DAPL cache" information */
     HDmemset(&H5CX_def_dapl_cache, 0, sizeof(H5CX_dapl_cache_t));
 
@@ -549,6 +569,22 @@ H5CX__init_package(void)
     if(H5P_peek(da_plist, H5D_ACS_VDS_PREFIX_NAME, &H5CX_def_dapl_cache.vds_prefix) < 0)
         HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "Can't retrieve prefix for VDS")
 
+    /* Reset the "default FAPL cache" information */
+    HDmemset(&H5CX_def_fapl_cache, 0, sizeof(H5CX_fapl_cache_t));
+
+    /* Get the default FAPL cache information */
+
+    /* Get the default file access property list */
+    if(NULL == (fa_plist = (H5P_genplist_t *)H5I_object(H5P_FILE_ACCESS_DEFAULT)))
+        HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, FAIL, "not a dataset create property list")
+
+    /* Get low_bound */
+    if(H5P_get(fa_plist, H5F_ACS_LIBVER_LOW_BOUND_NAME, &H5CX_def_fapl_cache.low_bound) < 0)
+        HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "Can't retrieve dataset minimize flag")
+
+    if(H5P_get(fa_plist, H5F_ACS_LIBVER_HIGH_BOUND_NAME, &H5CX_def_fapl_cache.high_bound) < 0)
+        HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "Can't retrieve dataset minimize flag")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5CX__init_package() */
@@ -675,6 +711,7 @@ H5CX__push_common(H5CX_node_t *cnode)
     cnode->ctx.dcpl_id = H5P_DATASET_CREATE_DEFAULT;
     cnode->ctx.dapl_id = H5P_DATASET_ACCESS_DEFAULT;
     cnode->ctx.lapl_id = H5P_LINK_ACCESS_DEFAULT;
+    cnode->ctx.fapl_id = H5P_FILE_ACCESS_DEFAULT;
     cnode->ctx.tag = H5AC__INVALID_TAG;
     cnode->ctx.ring = H5AC_RING_USER;
 
@@ -1053,6 +1090,42 @@ H5CX_set_dcpl(hid_t dcpl_id)
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5CX_set_dcpl() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5CX_set_libver_bounds
+ *
+ * Purpose:     Sets the low/high bounds according to "f" for the current API call context.
+ *              When "f" is NULL, the low/high bounds are set to latest format.
+ *
+ * Return:      Non-negative on success / Negative on failure
+ *
+ * Programmer:  Vailin Choi
+ *              March 27, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5CX_set_libver_bounds(H5F_t *f)
+{
+    H5CX_node_t **head = H5CX_get_my_context();  /* Get the pointer to the head of the API context, for this thread */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(head && *head);
+
+    /* Set the API context value */
+    (*head)->ctx.low_bound = (f == NULL) ? H5F_LIBVER_LATEST : H5F_LOW_BOUND(f);
+    (*head)->ctx.high_bound = (f == NULL) ? H5F_LIBVER_LATEST : H5F_HIGH_BOUND(f);
+
+    /* Mark the values as valid */
+    (*head)->ctx.low_bound_valid = TRUE;
+    (*head)->ctx.high_bound_valid = TRUE;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5CX_set_libver_bounds() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    H5CX_set_lapl
@@ -1124,6 +1197,7 @@ H5CX_set_apl(hid_t *acspl_id, const H5P_libclass_t *libclass,
     else {
         htri_t is_lapl;         /* Whether the access property list is (or is derived from) a link access property list */
         htri_t is_dapl;         /* Whether the access property list is (or is derived from) a dataset access property list */
+        htri_t is_fapl;         /* Whether the access property list is (or is derived from) a file access property list */
 
 #ifdef H5CX_DEBUG
         /* Sanity check the access property list class */
@@ -1143,6 +1217,12 @@ H5CX_set_apl(hid_t *acspl_id, const H5P_libclass_t *libclass,
         else if(is_dapl)
             (*head)->ctx.dapl_id = *acspl_id;
 
+        /* Check for file access property and set API context if so */
+        if((is_fapl = H5P_class_isa(*libclass->pclass, *H5P_CLS_FACC->pclass)) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "can't check for file access class")
+        else if(is_fapl)
+            (*head)->ctx.fapl_id = *acspl_id;
+
 #ifdef H5_HAVE_PARALLEL
         /* If this routine is not guaranteed to be collective (i.e. it doesn't
          * modify the structural metadata in a file), check if the application
@@ -2333,6 +2413,43 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5CX_get_nlinks() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5CX_get_libver_bounds
+ *
+ * Purpose:     Retrieves the low/high bounds for the current API call context.
+ *
+ * Return:      Non-negative on success / Negative on failure
+ *
+ * Programmer:  Vailin Choi
+ *              March 27, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5CX_get_libver_bounds(H5F_libver_t *low_bound, H5F_libver_t *high_bound)
+{
+    H5CX_node_t **head = H5CX_get_my_context();  /* Get the pointer to the head of the API context, for this thread */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(low_bound);
+    HDassert(high_bound);
+    HDassert(head && *head);
+    HDassert(H5P_DEFAULT != (*head)->ctx.fapl_id);
+
+    H5CX_RETRIEVE_PROP_VALID(fapl, H5P_FILE_ACCESS_DEFAULT, H5F_ACS_LIBVER_LOW_BOUND_NAME, low_bound)
+    H5CX_RETRIEVE_PROP_VALID(fapl, H5P_FILE_ACCESS_DEFAULT, H5F_ACS_LIBVER_HIGH_BOUND_NAME, high_bound)
+
+    /* Get the values */
+    *low_bound = (*head)->ctx.low_bound;
+    *high_bound = (*head)->ctx.high_bound;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5CX_get_libver_bounds() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    H5CX_get_dset_min_ohdr_flag
diff --git a/src/H5CXprivate.h b/src/H5CXprivate.h
index 2248ac9..638c32a 100644
--- a/src/H5CXprivate.h
+++ b/src/H5CXprivate.h
@@ -79,6 +79,7 @@ H5_DLL herr_t H5CX_free_state(H5CX_state_t *api_state);
 H5_DLL void H5CX_set_dxpl(hid_t dxpl_id);
 H5_DLL void H5CX_set_lapl(hid_t lapl_id);
 H5_DLL void H5CX_set_dcpl(hid_t dcpl_id);
+H5_DLL herr_t H5CX_set_libver_bounds(H5F_t *f);
 H5_DLL herr_t H5CX_set_apl(hid_t *acspl_id, const H5P_libclass_t *libclass,
     hid_t loc_id, hbool_t is_collective);
 H5_DLL herr_t H5CX_set_loc(hid_t loc_id);
@@ -131,6 +132,9 @@ H5_DLL herr_t H5CX_get_dset_min_ohdr_flag(hbool_t *dset_min_ohdr_flag);
 H5_DLL herr_t H5CX_get_ext_file_prefix(char **prefix_extfile);
 H5_DLL herr_t H5CX_get_vds_prefix(char **prefix_vds);
 
+/* "Getter" routines for FAPL properties cached in API context */
+H5_DLL herr_t H5CX_get_libver_bounds(H5F_libver_t *low_bound, H5F_libver_t *high_bound);
+
 /* "Setter" routines for API context info */
 H5_DLL void H5CX_set_tag(haddr_t tag);
 H5_DLL void H5CX_set_ring(H5AC_ring_t ring);
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
index 494d2c8..fb28489 100644
--- a/src/H5Dlayout.c
+++ b/src/H5Dlayout.c
@@ -50,6 +50,7 @@
 const unsigned H5O_layout_ver_bounds[] = {
     H5O_LAYOUT_VERSION_1,       /* H5F_LIBVER_EARLIEST */
     H5O_LAYOUT_VERSION_3,       /* H5F_LIBVER_V18 */  /* H5O_LAYOUT_VERSION_DEFAULT */
+    H5O_LAYOUT_VERSION_4,       /* H5F_LIBVER_V110 */
     H5O_LAYOUT_VERSION_LATEST   /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 03bbbd9..5d03b3b 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -3327,7 +3327,7 @@ H5F__start_swmr_write(H5F_t *f)
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "file superblock version - should be at least 3")
 
     /* Check for correct file format version */
-    if((f->shared->low_bound != H5F_LIBVER_V110) || (f->shared->high_bound != H5F_LIBVER_V110))
+    if((f->shared->low_bound < H5F_LIBVER_V110) || (f->shared->high_bound < H5F_LIBVER_V110))
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "file format version does not support SWMR - needs to be 1.10 or greater")
 
     /* Should not be marked for SWMR writing mode already */
diff --git a/src/H5Fpublic.h b/src/H5Fpublic.h
index 9f1ed01..8274654 100644
--- a/src/H5Fpublic.h
+++ b/src/H5Fpublic.h
@@ -178,11 +178,12 @@ typedef enum H5F_libver_t {
     H5F_LIBVER_ERROR = -1,
     H5F_LIBVER_EARLIEST = 0,    /* Use the earliest possible format for storing objects */
     H5F_LIBVER_V18 = 1,         /* Use the latest v18 format for storing objects */
-    H5F_LIBVER_V110 = 2,        /* Use the latest v10 format for storing objects */
+    H5F_LIBVER_V110 = 2,        /* Use the latest v110 format for storing objects */
+    H5F_LIBVER_V112 = 3,        /* Use the latest v112 format for storing objects */
     H5F_LIBVER_NBOUNDS
 } H5F_libver_t;
 
-#define H5F_LIBVER_LATEST   H5F_LIBVER_V110
+#define H5F_LIBVER_LATEST   H5F_LIBVER_V112
 
 /* File space handling strategy */
 typedef enum H5F_fspace_strategy_t {
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 3c225a2..aa5a85d 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -76,6 +76,7 @@ H5FL_DEFINE(H5F_super_t);
 static const unsigned HDF5_superblock_ver_bounds[] = {
     HDF5_SUPERBLOCK_VERSION_DEF,    /* H5F_LIBVER_EARLIEST */
     HDF5_SUPERBLOCK_VERSION_2,      /* H5F_LIBVER_V18 */
+    HDF5_SUPERBLOCK_VERSION_3,      /* H5F_LIBVER_V110 */
     HDF5_SUPERBLOCK_VERSION_LATEST  /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5Ofill.c b/src/H5Ofill.c
index ebd885c..d87dc84 100644
--- a/src/H5Ofill.c
+++ b/src/H5Ofill.c
@@ -157,6 +157,7 @@ const H5O_msg_class_t H5O_MSG_FILL_NEW[1] = {{
 const unsigned H5O_fill_ver_bounds[] = {
     H5O_FILL_VERSION_1,     /* H5F_LIBVER_EARLIEST */
     H5O_FILL_VERSION_2,     /* H5F_LIBVER_V18 */
+    H5O_FILL_VERSION_3,     /* H5F_LIBVER_V110 */
     H5O_FILL_VERSION_LATEST /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5Oint.c b/src/H5Oint.c
index 570f94e..60aae45 100644
--- a/src/H5Oint.c
+++ b/src/H5Oint.c
@@ -130,6 +130,7 @@ const H5O_msg_class_t *const H5O_msg_class_g[] = {
 const unsigned H5O_obj_ver_bounds[] = {
     H5O_VERSION_1,      /* H5F_LIBVER_EARLIEST */
     H5O_VERSION_2,      /* H5F_LIBVER_V18 */
+    H5O_VERSION_2,      /* H5F_LIBVER_V110 */
     H5O_VERSION_LATEST  /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5Opline.c b/src/H5Opline.c
index 85a95b7..609f2eb 100644
--- a/src/H5Opline.c
+++ b/src/H5Opline.c
@@ -93,6 +93,7 @@ const H5O_msg_class_t H5O_MSG_PLINE[1] = {{
 const unsigned H5O_pline_ver_bounds[] = {
     H5O_PLINE_VERSION_1,        /* H5F_LIBVER_EARLIEST */
     H5O_PLINE_VERSION_2,        /* H5F_LIBVER_V18 */
+    H5O_PLINE_VERSION_2,        /* H5F_LIBVER_V110 */
     H5O_PLINE_VERSION_LATEST    /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5S.c b/src/H5S.c
index bf30a26..301060f 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -66,6 +66,7 @@ hbool_t H5_PKG_INIT_VAR = FALSE;
 const unsigned H5O_sdspace_ver_bounds[] = {
     H5O_SDSPACE_VERSION_1,      /* H5F_LIBVER_EARLIEST */
     H5O_SDSPACE_VERSION_2,      /* H5F_LIBVER_V18 */
+    H5O_SDSPACE_VERSION_2,      /* H5F_LIBVER_V110 */
     H5O_SDSPACE_VERSION_LATEST  /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5Sall.c b/src/H5Sall.c
index 0aa2f05..9823d36 100644
--- a/src/H5Sall.c
+++ b/src/H5Sall.c
@@ -58,8 +58,7 @@ static herr_t H5S__all_release(H5S_t *space);
 static htri_t H5S__all_is_valid(const H5S_t *space);
 static hssize_t H5S__all_serial_size(const H5S_t *space);
 static herr_t H5S__all_serialize(const H5S_t *space, uint8_t **p);
-static herr_t H5S__all_deserialize(H5S_t *space, uint32_t version, uint8_t flags,
-    const uint8_t **p);
+static herr_t H5S__all_deserialize(H5S_t **space, const uint8_t **p);
 static herr_t H5S__all_bounds(const H5S_t *space, hsize_t *start, hsize_t *end);
 static herr_t H5S__all_offset(const H5S_t *space, hsize_t *off);
 static int H5S__all_unlim_dim(const H5S_t *space);
@@ -648,10 +647,8 @@ H5S__all_serialize(const H5S_t *space, uint8_t **p)
     Deserialize the current selection from a user-provided buffer.
  USAGE
     herr_t H5S_all_deserialize(space, p)
-        H5S_t *space;           IN/OUT: Dataspace pointer to place
+        H5S_t **space;          IN/OUT: Dataspace pointer to place
                                 selection into
-        uint32_t version        IN: Selection version
-        uint8_t flags           IN: Selection flags
         uint8 **p;              OUT: Pointer to buffer holding serialized
                                 selection.  Will be advanced to end of
                                 serialized selection.
@@ -666,22 +663,51 @@ H5S__all_serialize(const H5S_t *space, uint8_t **p)
  REVISION LOG
 --------------------------------------------------------------------------*/
 static herr_t
-H5S__all_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t H5_ATTR_UNUSED flags,
-        const uint8_t H5_ATTR_UNUSED **p)
+H5S__all_deserialize(H5S_t **space, const uint8_t **p)
 {
+    uint32_t version;           /* Version number */
+    H5S_t *tmp_space = NULL;    /* Pointer to actual dataspace to use,
+                                   either *space or a newly allocated one */
     herr_t ret_value = SUCCEED;   /* return value */
 
     FUNC_ENTER_STATIC
 
-    HDassert(space);
     HDassert(p);
     HDassert(*p);
 
+    /* As part of the efforts to push all selection-type specific coding
+       to the callbacks, the coding for the allocation of a null dataspace 
+       is moved from H5S_select_deserialize() in H5Sselect.c.
+       This is needed for decoding virtual layout in H5O__layout_decode() */
+
+    /* Allocate space if not provided */
+    if(!*space) {
+        if(NULL == (tmp_space = H5S_create(H5S_SIMPLE)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create dataspace")
+    } /* end if */
+    else
+        tmp_space = *space;
+
+    /* Decode version */
+    UINT32DECODE(*p, version);
+
+    /* Skip over the remainder of the header */
+    *p += 8;
+
     /* Change to "all" selection */
-    if(H5S_select_all(space, TRUE) < 0)
+    if(H5S_select_all(tmp_space, TRUE) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
 
+    /* Return space to the caller if allocated */
+    if(!*space)
+        *space = tmp_space;
+
 done:
+    /* Free temporary space if not passed to caller (only happens on error) */
+    if(!*space && tmp_space)
+        if(H5S_close(tmp_space) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5S__all_deserialize() */
 
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index 4cb5e28..6d42ec1 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -95,8 +95,7 @@ static herr_t H5S__hyper_release(H5S_t *space);
 static htri_t H5S__hyper_is_valid(const H5S_t *space);
 static hssize_t H5S__hyper_serial_size(const H5S_t *space);
 static herr_t H5S__hyper_serialize(const H5S_t *space, uint8_t **p);
-static herr_t H5S__hyper_deserialize(H5S_t *space, uint32_t version, uint8_t flags,
-    const uint8_t **p);
+static herr_t H5S__hyper_deserialize(H5S_t **space, const uint8_t **p);
 static herr_t H5S__hyper_bounds(const H5S_t *space, hsize_t *start, hsize_t *end);
 static herr_t H5S__hyper_offset(const H5S_t *space, hsize_t *offset);
 static int H5S__hyper_unlim_dim(const H5S_t *space);
@@ -3456,7 +3455,7 @@ H5S__hyper_serialize_helper(const H5S_hyper_span_info_t *spans,
 static herr_t
 H5S__hyper_serialize(const H5S_t *space, uint8_t **p)
 {
-    uint8_t *pp;            /* Local pointer for decoding */
+    uint8_t *pp;            /* Local pointer for encoding */
     uint8_t *lenp;          /* Pointer to length location for later storage */
     uint32_t len = 0;       /* Number of bytes used */
     uint32_t version;       /* Version number */
@@ -3507,6 +3506,7 @@ H5S__hyper_serialize(const H5S_t *space, uint8_t **p)
             UINT64ENCODE(pp, space->select.sel_info.hslab->opt_diminfo[i].count);
             UINT64ENCODE(pp, space->select.sel_info.hslab->opt_diminfo[i].block);
         } /* end for */
+        len += (4 * space->extent.rank * 8);
     } /* end if */
     /* Check for a "regular" hyperslab selection */
     else if(space->select.sel_info.hslab->diminfo_valid) {
@@ -3636,10 +3636,8 @@ H5S__hyper_serialize(const H5S_t *space, uint8_t **p)
     Deserialize the current selection from a user-provided buffer.
  USAGE
     herr_t H5S__hyper_deserialize(space, p)
-        H5S_t *space;           IN/OUT: Dataspace pointer to place
+        H5S_t **space;          IN/OUT: Dataspace pointer to place
                                 selection into
-        uint32_t version        IN: Selection version
-        uint8_t flags           IN: Selection flags
         uint8 **p;              OUT: Pointer to buffer holding serialized
                                 selection.  Will be advanced to end of
                                 serialized selection.
@@ -3654,27 +3652,65 @@ H5S__hyper_serialize(const H5S_t *space, uint8_t **p)
  REVISION LOG
 --------------------------------------------------------------------------*/
 static herr_t
-H5S__hyper_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t flags,
-    const uint8_t **p)
+H5S__hyper_deserialize(H5S_t **space, const uint8_t **p)
 {
-    unsigned rank;           	/* Rank of points */
-    const uint8_t *pp;          /* Local pointer for decoding */
-    hsize_t start[H5S_MAX_RANK]; /* Hyperslab start information */
-    hsize_t block[H5S_MAX_RANK]; /* Hyperslab block information */
-    unsigned u;             	/* Local counting variable */
-    herr_t ret_value = FAIL;  	/* Return value */
+    H5S_t *tmp_space = NULL;        /* Pointer to actual dataspace to use,
+                                       either *space or a newly allocated one */
+    hsize_t dims[H5S_MAX_RANK];     /* Dimenion sizes */
+    hsize_t start[H5S_MAX_RANK];    /* Hyperslab start information */
+    hsize_t block[H5S_MAX_RANK];    /* Hyperslab block information */
+    uint32_t version;               /* Version number */
+    uint8_t flags = 0;              /* Flags */
+    unsigned rank;           	    /* Rank of points */
+    const uint8_t *pp;              /* Local pointer for decoding */
+    unsigned u;             	    /* Local counting variable */
+    herr_t ret_value = FAIL;  	    /* Return value */
 
     FUNC_ENTER_STATIC
 
     /* Check args */
-    HDassert(space);
     HDassert(p);
     pp = (*p);
     HDassert(pp);
 
-    /* Deserialize slabs to select */
-    /* (The header and rank have already beed decoded) */
-    rank = space->extent.rank;  /* Retrieve rank from space */
+    /* As part of the efforts to push all selection-type specific coding
+       to the callbacks, the coding for the allocation of a null dataspace
+       is moved from H5S_select_deserialize() in H5Sselect.c to here.
+       This is needed for decoding virtual layout in H5O__layout_decode() */
+    /* Allocate space if not provided */
+    if(!*space) {
+        if(NULL == (tmp_space = H5S_create(H5S_SIMPLE)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create dataspace")
+    } /* end if */
+    else
+        tmp_space = *space;
+
+    /* Decode version */
+    UINT32DECODE(pp, version);
+
+    if(version >= (uint32_t)2) {
+        /* Decode flags */
+        flags = *(pp)++;
+
+        /* Skip over the remainder of the header */
+        pp += 4;
+    } else
+        /* Skip over the remainder of the header */
+        pp += 8;
+
+    /* Decode the rank of the point selection */
+    UINT32DECODE(pp,rank);
+
+    if(!*space) {
+        /* Patch the rank of the allocated dataspace */
+        (void)HDmemset(dims, 0, (size_t)rank * sizeof(dims[0]));
+        if(H5S_set_extent_simple(tmp_space, rank, dims, NULL) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't set dimensions")
+    } /* end if */
+    else
+        /* Verify the rank of the provided dataspace */
+        if(rank != tmp_space->extent.rank)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "rank of serialized selection does not match dataspace")
 
     /* If there is an unlimited dimension, only encode opt_unlim_diminfo */
     if(flags & H5S_SELECT_FLAG_UNLIM) {
@@ -3695,7 +3731,7 @@ H5S__hyper_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t fl
         } /* end for */
 
         /* Select the hyperslab to the current selection */
-        if((ret_value = H5S_select_hyperslab(space, H5S_SELECT_SET, start, stride, count, block)) < 0)
+        if((ret_value = H5S_select_hyperslab(tmp_space, H5S_SELECT_SET, start, stride, count, block)) < 0)
             HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "can't change selection")
     } /* end if */
     else {
@@ -3729,7 +3765,7 @@ H5S__hyper_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t fl
                 *tblock = (*tend - *tstart) + 1;
 
             /* Select or add the hyperslab to the current selection */
-            if((ret_value = H5S_select_hyperslab(space, (u == 0 ? H5S_SELECT_SET : H5S_SELECT_OR), start, stride, count, block)) < 0)
+            if((ret_value = H5S_select_hyperslab(tmp_space, (u == 0 ? H5S_SELECT_SET : H5S_SELECT_OR), start, stride, count, block)) < 0)
                 HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSET, FAIL, "can't change selection")
         } /* end for */
     } /* end else */
@@ -3737,7 +3773,16 @@ H5S__hyper_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t fl
     /* Update decoding pointer */
     *p = pp;
 
+    /* Return space to the caller if allocated */
+    if(!*space)
+        *space = tmp_space;
+
 done:
+    /* Free temporary space if not passed to caller (only happens on error) */
+    if(!*space && tmp_space)
+        if(H5S_close(tmp_space) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5S__hyper_deserialize() */
 
diff --git a/src/H5Snone.c b/src/H5Snone.c
index 86994dd..cae9a67 100644
--- a/src/H5Snone.c
+++ b/src/H5Snone.c
@@ -58,8 +58,7 @@ static herr_t H5S__none_release(H5S_t *space);
 static htri_t H5S__none_is_valid(const H5S_t *space);
 static hssize_t H5S__none_serial_size(const H5S_t *space);
 static herr_t H5S__none_serialize(const H5S_t *space, uint8_t **p);
-static herr_t H5S__none_deserialize(H5S_t *space, uint32_t version, uint8_t flags,
-    const uint8_t **p);
+static herr_t H5S__none_deserialize(H5S_t **space, const uint8_t **p);
 static herr_t H5S__none_bounds(const H5S_t *space, hsize_t *start, hsize_t *end);
 static herr_t H5S__none_offset(const H5S_t *space, hsize_t *off);
 static int H5S__none_unlim_dim(const H5S_t *space);
@@ -602,10 +601,8 @@ H5S__none_serialize(const H5S_t *space, uint8_t **p)
     Deserialize the current selection from a user-provided buffer.
  USAGE
     herr_t H5S__none_deserialize(space, version, flags, p)
-        H5S_t *space;           IN/OUT: Dataspace pointer to place
+        H5S_t **space;          IN/OUT: Dataspace pointer to place
                                 selection into
-        uint32_t version        IN: Selection version
-        uint8_t flags           IN: Selection flags
         uint8 **p;              OUT: Pointer to buffer holding serialized
                                 selection.  Will be advanced to end of
                                 serialized selection.
@@ -620,22 +617,50 @@ H5S__none_serialize(const H5S_t *space, uint8_t **p)
  REVISION LOG
 --------------------------------------------------------------------------*/
 static herr_t
-H5S__none_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version,
-    uint8_t H5_ATTR_UNUSED flags, const uint8_t H5_ATTR_UNUSED **p)
+H5S__none_deserialize(H5S_t **space, const uint8_t **p)
 {
-    herr_t ret_value = SUCCEED;  /* return value */
+    H5S_t *tmp_space = NULL;    /* Pointer to actual dataspace to use,
+                                   either *space or a newly allocated one */
+    uint32_t version;           /* Version number */
+    herr_t ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_STATIC
 
-    HDassert(space);
     HDassert(p);
     HDassert(*p);
 
+    /* As part of the efforts to push all selection-type specific coding
+       to the callbacks, the coding for the allocation of a null dataspace
+       is moved from H5S_select_deserialize() in H5Sselect.c to here.
+       This is needed for decoding virtual layout in H5O__layout_decode() */
+    /* Allocate space if not provided */
+    if(!*space) {
+        if(NULL == (tmp_space = H5S_create(H5S_SIMPLE)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create dataspace")
+    } /* end if */
+    else
+        tmp_space = *space;
+
+    /* Decode version */
+    UINT32DECODE(*p, version);
+
+    /* Skip over the remainder of the header */
+    *p += 8;
+
     /* Change to "none" selection */
-    if(H5S_select_none(space) < 0)
+    if(H5S_select_none(tmp_space) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
 
+    /* Return space to the caller if allocated */
+    if(!*space)
+        *space = tmp_space;
+
 done:
+    /* Free temporary space if not passed to caller (only happens on error) */
+    if(!*space && tmp_space)
+        if(H5S_close(tmp_space) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5S__none_deserialize() */
 
diff --git a/src/H5Spkg.h b/src/H5Spkg.h
index 0575f03..2918648 100644
--- a/src/H5Spkg.h
+++ b/src/H5Spkg.h
@@ -148,8 +148,7 @@ typedef hssize_t (*H5S_sel_serial_size_func_t)(const H5S_t *space);
 /* Method to store current selection in "serialized" form (a byte sequence suitable for storing on disk) */
 typedef herr_t (*H5S_sel_serialize_func_t)(const H5S_t *space, uint8_t **p);
 /* Method to create selection from "serialized" form (a byte sequence suitable for storing on disk) */
-typedef herr_t (*H5S_sel_deserialize_func_t)(H5S_t *space, uint32_t version, uint8_t flags,
-    const uint8_t **p);
+typedef herr_t (*H5S_sel_deserialize_func_t)(H5S_t **space, const uint8_t **p);
 /* Method to determine smallest n-D bounding box containing the current selection */
 typedef herr_t (*H5S_sel_bounds_func_t)(const H5S_t *space, hsize_t *start, hsize_t *end);
 /* Method to determine linear offset of initial element in selection within dataspace */
diff --git a/src/H5Spoint.c b/src/H5Spoint.c
index e62b48d..ac9c983 100644
--- a/src/H5Spoint.c
+++ b/src/H5Spoint.c
@@ -60,8 +60,7 @@ static herr_t H5S__point_release(H5S_t *space);
 static htri_t H5S__point_is_valid(const H5S_t *space);
 static hssize_t H5S__point_serial_size(const H5S_t *space);
 static herr_t H5S__point_serialize(const H5S_t *space, uint8_t **p);
-static herr_t H5S__point_deserialize(H5S_t *space, uint32_t version, uint8_t flags,
-    const uint8_t **p);
+static herr_t H5S__point_deserialize(H5S_t **space, const uint8_t **p);
 static herr_t H5S__point_bounds(const H5S_t *space, hsize_t *start, hsize_t *end);
 static herr_t H5S__point_offset(const H5S_t *space, hsize_t *off);
 static int H5S__point_unlim_dim(const H5S_t *space);
@@ -988,7 +987,7 @@ static herr_t
 H5S__point_serialize(const H5S_t *space, uint8_t **p)
 {
     H5S_pnt_node_t *curr;       /* Point information nodes */
-    uint8_t *pp = (*p);         /* Local pointer for decoding */
+    uint8_t *pp;                /* Local pointer for encoding */
     uint8_t *lenp;              /* Pointer to length location for later storage */
     uint32_t len = 0;           /* Number of bytes used */
     unsigned u;                 /* Local counting variable */
@@ -998,6 +997,7 @@ H5S__point_serialize(const H5S_t *space, uint8_t **p)
     /* Check args */
     HDassert(space);
     HDassert(p);
+    pp = (*p);
     HDassert(pp);
 
     /* Store the preamble information */
@@ -1045,10 +1045,8 @@ H5S__point_serialize(const H5S_t *space, uint8_t **p)
     Deserialize the current selection from a user-provided buffer.
  USAGE
     herr_t H5S__point_deserialize(space, p)
-        H5S_t *space;           IN/OUT: Dataspace pointer to place
+        H5S_t **space;          IN/OUT: Dataspace pointer to place
                                 selection into
-        uint32_t version        IN: Selection version
-        uint8_t flags           IN: Selection flags
         uint8 **p;              OUT: Pointer to buffer holding serialized
                                 selection.  Will be advanced to end of
                                 serialized selection.
@@ -1063,11 +1061,14 @@ H5S__point_serialize(const H5S_t *space, uint8_t **p)
  REVISION LOG
 --------------------------------------------------------------------------*/
 static herr_t
-H5S__point_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t H5_ATTR_UNUSED flags,
-    const uint8_t **p)
+H5S__point_deserialize(H5S_t **space, const uint8_t **p)
 {
+    H5S_t *tmp_space = NULL;    /* Pointer to actual dataspace to use,
+                                   either *space or a newly allocated one */
+    hsize_t dims[H5S_MAX_RANK]; /* Dimension sizes */
+    uint32_t version;           /* Version number */
     hsize_t *coord = NULL, *tcoord;     /* Pointer to array of elements */
-    const uint8_t *pp = (*p);   /* Local pointer for decoding */
+    const uint8_t *pp;          /* Local pointer for decoding */
     size_t num_elem = 0;        /* Number of elements in selection */
     unsigned rank;              /* Rank of points */
     unsigned i, j;              /* local counting variables */
@@ -1076,13 +1077,43 @@ H5S__point_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t H5
     FUNC_ENTER_STATIC
 
     /* Check args */
-    HDassert(space);
     HDassert(p);
+    pp = (*p);
     HDassert(pp);
 
+    /* As part of the efforts to push all selection-type specific coding
+       to the callbacks, the coding for the allocation of a null dataspace
+       is moved from H5S_select_deserialize() in H5Sselect.c to here.
+       This is needed for decoding virtual layout in H5O__layout_decode() */
+    /* Allocate space if not provided */
+    if(!*space) {
+        if(NULL == (tmp_space = H5S_create(H5S_SIMPLE)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create dataspace")
+    } /* end if */
+    else
+        tmp_space = *space;
+
+    /* Decode version */
+    UINT32DECODE(pp, version);
+
+    /* Skip over the remainder of the header */
+    pp += 8;
+
+    /* Decode the rank of the point selection */
+    UINT32DECODE(pp,rank);
+
+    if(!*space) {
+        /* Patch the rank of the allocated dataspace */
+        (void)HDmemset(dims, 0, (size_t)rank * sizeof(dims[0]));
+        if(H5S_set_extent_simple(tmp_space, rank, dims, NULL) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't set dimensions")
+    } /* end if */
+    else
+        /* Verify the rank of the provided dataspace */
+        if(rank != tmp_space->extent.rank)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "rank of serialized selection does not match dataspace")
+
     /* Deserialize points to select */
-    /* (The header and rank have already beed decoded) */
-    rank = space->extent.rank;  /* Retrieve rank from space */
     UINT32DECODE(pp, num_elem); /* decode the number of points */
 
     /* Allocate space for the coordinates */
@@ -1095,13 +1126,22 @@ H5S__point_deserialize(H5S_t *space, uint32_t H5_ATTR_UNUSED version, uint8_t H5
             UINT32DECODE(pp, *tcoord);
 
     /* Select points */
-    if(H5S_select_elements(space, H5S_SELECT_SET, num_elem, (const hsize_t *)coord) < 0)
+    if(H5S_select_elements(tmp_space, H5S_SELECT_SET, num_elem, (const hsize_t *)coord) < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
 
     /* Update decoding pointer */
     *p = pp;
 
+    /* Return space to the caller if allocated */
+    if(!*space)
+        *space = tmp_space;
+
 done:
+    /* Free temporary space if not passed to caller (only happens on error) */
+    if(!*space && tmp_space)
+        if(H5S_close(tmp_space) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace")
+
     /* Free the coordinate array if necessary */
     if(coord != NULL)
         H5MM_xfree(coord);
diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index ef38746..aaea203 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -544,101 +544,44 @@ H5S_select_valid(const H5S_t *space)
 herr_t
 H5S_select_deserialize(H5S_t **space, const uint8_t **p)
 {
-    H5S_t *tmp_space = NULL;    /* Pointer to actual dataspace to use, either
-                                 *space or a newly allocated one */
     uint32_t sel_type;          /* Pointer to the selection type */
-    uint32_t version;           /* Version number */
-    uint8_t flags = 0;          /* Flags */
     herr_t ret_value = FAIL;    /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     HDassert(space);
 
-    /* Allocate space if not provided */
-    if(!*space) {
-        if(NULL == (tmp_space = H5S_create(H5S_SIMPLE)))
-            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create dataspace")
-    } /* end if */
-    else
-        tmp_space = *space;
+    /* Selection-type specific coding is moved to the callbacks. */
 
     /* Decode selection type */
     UINT32DECODE(*p, sel_type);
 
-    /* Decode version */
-    UINT32DECODE(*p, version);
-
-    if(version >= (uint32_t)2) {
-        /* Decode flags */
-        flags = *(*p)++;
-
-        /* Check for unknown flags */
-        if(flags & ~H5S_SELECT_FLAG_BITS)
-            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTLOAD, FAIL, "unknown flag for selection")
-
-        /* Skip over the remainder of the header */
-        *p += 4;
-    } /* end if */
-    else
-        /* Skip over the remainder of the header */
-        *p += 8;
-
-    /* Decode and check or patch rank for point and hyperslab selections */
-    if((sel_type == H5S_SEL_POINTS) || (sel_type == H5S_SEL_HYPERSLABS)) {
-        uint32_t rank;              /* Rank of dataspace */
-
-        /* Decode the rank of the point selection */
-        UINT32DECODE(*p,rank);
-
-        if(!*space) {
-            hsize_t dims[H5S_MAX_RANK];
-
-            /* Patch the rank of the allocated dataspace */
-            (void)HDmemset(dims, 0, (size_t)rank * sizeof(dims[0]));
-            if(H5S_set_extent_simple(tmp_space, rank, dims, NULL) < 0)
-                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTINIT, FAIL, "can't set dimensions")
-        } /* end if */
-        else
-            /* Verify the rank of the provided dataspace */
-            if(rank != tmp_space->extent.rank)
-                HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "rank of serialized selection does not match dataspace")
-    } /* end if */
-
     /* Make routine for selection type */
     switch(sel_type) {
         case H5S_SEL_POINTS:         /* Sequence of points selected */
-            ret_value = (*H5S_sel_point->deserialize)(tmp_space, version, flags, p);
+            ret_value = (*H5S_sel_point->deserialize)(space, p);
             break;
 
         case H5S_SEL_HYPERSLABS:     /* Hyperslab selection defined */
-            ret_value = (*H5S_sel_hyper->deserialize)(tmp_space, version, flags, p);
+            ret_value = (*H5S_sel_hyper->deserialize)(space, p);
             break;
 
         case H5S_SEL_ALL:            /* Entire extent selected */
-            ret_value = (*H5S_sel_all->deserialize)(tmp_space, version, flags, p);
+            ret_value = (*H5S_sel_all->deserialize)(space, p);
             break;
 
         case H5S_SEL_NONE:           /* Nothing selected */
-            ret_value = (*H5S_sel_none->deserialize)(tmp_space, version, flags, p);
+            ret_value = (*H5S_sel_none->deserialize)(space, p);
             break;
 
         default:
             break;
     } /* end switch */
+
     if(ret_value < 0)
         HGOTO_ERROR(H5E_DATASPACE, H5E_CANTLOAD, FAIL, "can't deserialize selection")
 
-    /* Return space to the caller if allocated */
-    if(!*space)
-        *space = tmp_space;
-
 done:
-    /* Free temporary space if not passed to caller (only happens on error) */
-    if(!*space && tmp_space)
-        if(H5S_close(tmp_space) < 0)
-            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace")
-
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5S_select_deserialize() */
 
diff --git a/src/H5T.c b/src/H5T.c
index 1c4acb9..8c8a9b7 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -513,6 +513,7 @@ H5FL_DEFINE(H5T_shared_t);
 const unsigned H5O_dtype_ver_bounds[] = {
     H5O_DTYPE_VERSION_1,        /* H5F_LIBVER_EARLIEST */
     H5O_DTYPE_VERSION_3,        /* H5F_LIBVER_V18 */
+    H5O_DTYPE_VERSION_3,        /* H5F_LIBVER_V110 */
     H5O_DTYPE_VERSION_LATEST    /* H5F_LIBVER_LATEST */
 };
 
diff --git a/src/H5trace.c b/src/H5trace.c
index 9a13193..23f2f1d 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -1054,7 +1054,11 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                                     break;
 
                                 case H5F_LIBVER_V110:
-                                    HDcompile_assert(H5F_LIBVER_LATEST == H5F_LIBVER_V110);
+                                    HDfprintf(out, "H5F_LIBVER_V110");
+                                    break;
+
+                                case H5F_LIBVER_V112:
+                                    HDcompile_assert(H5F_LIBVER_LATEST == H5F_LIBVER_V112);
                                     HDfprintf(out, "H5F_LIBVER_LATEST");
                                     break;