[svn-r13250] Description:

	Add support for inserting attributes into creation order index.

	Also, update support for dense link & attribute storage in h5debug.

Tested on:
	FreeBSD/32 6.2 (duty)
	Mac OS X/32 10.4.8 (amazon)

17 files changed, 589 insertions, 52 deletions

diff --git a/src/H5Abtree2.c b/src/H5Abtree2.c
index 14d7bb9..25abd92 100644
--- a/src/H5Abtree2.c
+++ b/src/H5Abtree2.c
@@ -77,6 +77,17 @@ typedef struct H5A_fh_ud_cmp_t {
 
 /* v2 B-tree function callbacks */
 
+/* v2 B-tree driver callbacks for 'creation order' index */
+static herr_t H5A_dense_btree2_corder_store(void *native, const void *udata);
+static herr_t H5A_dense_btree2_corder_retrieve(void *udata, const void *native);
+static herr_t H5A_dense_btree2_corder_compare(const void *rec1, const void *rec2);
+static herr_t H5A_dense_btree2_corder_encode(const H5F_t *f, uint8_t *raw,
+    const void *native);
+static herr_t H5A_dense_btree2_corder_decode(const H5F_t *f, const uint8_t *raw,
+    void *native);
+static herr_t H5A_dense_btree2_corder_debug(FILE *stream, const H5F_t *f, hid_t dxpl_id,
+    int indent, int fwidth, const void *record, const void *_udata);
+
 /* v2 B-tree driver callbacks for 'name' index */
 static herr_t H5A_dense_btree2_name_store(void *native, const void *udata);
 static herr_t H5A_dense_btree2_name_retrieve(void *udata, const void *native);
@@ -95,7 +106,7 @@ static herr_t H5A_dense_fh_name_cmp(const void *obj, size_t obj_len, void *op_da
 /*********************/
 /* Package Variables */
 /*********************/
-/* v2 B-tree class for indexing 'name' field of links */
+/* v2 B-tree class for indexing 'name' field of attributes */
 const H5B2_class_t H5A_BT2_NAME[1]={{  /* B-tree class information */
     H5B2_ATTR_DENSE_NAME_ID,                /* Type of B-tree */
     sizeof(H5A_dense_bt2_name_rec_t),  /* Size of native record */
@@ -107,6 +118,18 @@ const H5B2_class_t H5A_BT2_NAME[1]={{  /* B-tree class information */
     H5A_dense_btree2_name_debug        /* Record debugging callback */
 }};
 
+/* v2 B-tree class for indexing 'creation order' field of attributes */
+const H5B2_class_t H5A_BT2_CORDER[1]={{  /* B-tree class information */
+    H5B2_ATTR_DENSE_CORDER_ID,                /* Type of B-tree */
+    sizeof(H5A_dense_bt2_corder_rec_t),/* Size of native record */
+    H5A_dense_btree2_corder_store,     /* Record storage callback */
+    H5A_dense_btree2_corder_retrieve,  /* Record retrieval callback */
+    H5A_dense_btree2_corder_compare,   /* Record comparison callback */
+    H5A_dense_btree2_corder_encode,    /* Record encoding callback */
+    H5A_dense_btree2_corder_decode,    /* Record decoding callback */
+    H5A_dense_btree2_corder_debug      /* Record debugging callback */
+}};
+
 
 /*****************************/
 /* Library Private Variables */
@@ -142,7 +165,7 @@ H5A_dense_fh_name_cmp(const void *obj, size_t UNUSED obj_len, void *_udata)
 
     FUNC_ENTER_NOAPI_NOINIT(H5A_dense_fh_name_cmp)
 
-    /* Decode link information */
+    /* Decode attribute information */
     if(NULL == (attr = (H5A_t *)H5O_msg_decode(udata->f, udata->dxpl_id, H5O_ATTR_ID, (const unsigned char *)obj)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, FAIL, "can't decode attribute")
 
@@ -155,6 +178,9 @@ H5A_dense_fh_name_cmp(const void *obj, size_t UNUSED obj_len, void *_udata)
         if(udata->record->flags & H5O_MSG_FLAG_SHARED)
             H5SM_reconstitute(&(attr->sh_loc), udata->record->id);
 
+        /* Set the creation order index for the attribute */
+        attr->crt_idx = udata->record->corder;
+
         /* Make callback */
         if((udata->found_op)(attr, udata->found_op_data) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTOPERATE, FAIL, "attribute found callback failed")
@@ -191,9 +217,10 @@ H5A_dense_btree2_name_store(void *_nrecord, const void *_udata)
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_name_store)
 
     /* Copy user information info native record */
-    nrecord->hash = udata->common.name_hash;
-    nrecord->flags = udata->common.flags;
     nrecord->id = udata->id;
+    nrecord->flags = udata->common.flags;
+    nrecord->corder = udata->common.corder;
+    nrecord->hash = udata->common.name_hash;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5A_dense_btree2_name_store() */
@@ -252,9 +279,9 @@ H5A_dense_btree2_name_compare(const void *_bt2_udata, const void *_bt2_rec)
 
     /* Check hash value */
     if(bt2_udata->name_hash < bt2_rec->hash)
-        HGOTO_DONE(-1)
+        ret_value = (-1);
     else if(bt2_udata->name_hash > bt2_rec->hash)
-        HGOTO_DONE(1)
+        ret_value = 1;
     else {
         H5A_fh_ud_cmp_t fh_udata;       /* User data for fractal heap 'op' callback */
         H5HF_t *fheap;                  /* Fractal heap handle to use for finding object */
@@ -282,15 +309,14 @@ H5A_dense_btree2_name_compare(const void *_bt2_udata, const void *_bt2_rec)
             fheap = bt2_udata->fheap;
         HDassert(fheap);
 
-        /* Check if the user's link and the B-tree's link have the same name */
+        /* Check if the user's attribute and the B-tree's attribute have the same name */
         status = H5HF_op(fheap, bt2_udata->dxpl_id, &bt2_rec->id, H5A_dense_fh_name_cmp, &fh_udata);
         HDassert(status >= 0);
 
         /* Callback will set comparison value */
-        HGOTO_DONE(fh_udata.cmp)
+        ret_value = fh_udata.cmp;
     } /* end else */
 
-done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5A_dense_btree2_name_compare() */
 
@@ -316,9 +342,10 @@ H5A_dense_btree2_name_encode(const H5F_t UNUSED *f, uint8_t *raw, const void *_n
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_name_encode)
 
     /* Encode the record's fields */
-    UINT32ENCODE(raw, nrecord->hash)
-    *raw++ = nrecord->flags;
     UINT64ENCODE(raw, nrecord->id);
+    *raw++ = nrecord->flags;
+    UINT32ENCODE(raw, nrecord->corder)
+    UINT32ENCODE(raw, nrecord->hash)
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5A_dense_btree2_name_encode() */
@@ -345,9 +372,10 @@ H5A_dense_btree2_name_decode(const H5F_t UNUSED *f, const uint8_t *raw, void *_n
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_name_decode)
 
     /* Decode the record's fields */
-    UINT32DECODE(raw, nrecord->hash)
-    nrecord->flags = *raw++;
     UINT64DECODE(raw, nrecord->id);
+    nrecord->flags = *raw++;
+    UINT32DECODE(raw, nrecord->corder)
+    UINT32DECODE(raw, nrecord->hash)
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5A_dense_btree2_name_decode() */
@@ -374,9 +402,190 @@ H5A_dense_btree2_name_debug(FILE *stream, const H5F_t UNUSED *f, hid_t UNUSED dx
 
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_name_debug)
 
-    HDfprintf(stream, "%*s%-*s {%lx, %Hx, %02x}", indent, "", fwidth, "Record:",
-        nrecord->hash, nrecord->id, nrecord->flags);
+    HDfprintf(stream, "%*s%-*s {%016Hx, %02x, %u, %08lx}\n", indent, "", fwidth,
+        "Record:",
+        (hsize_t)nrecord->id, (unsigned)nrecord->flags, (unsigned)nrecord->corder, (unsigned long)nrecord->hash);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5A_dense_btree2_name_debug() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_store
+ *
+ * Purpose:	Store user information into native record for v2 B-tree
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_store(void *_nrecord, const void *_udata)
+{
+    const H5A_bt2_ud_ins_t *udata = (const H5A_bt2_ud_ins_t *)_udata;
+    H5A_dense_bt2_corder_rec_t *nrecord = (H5A_dense_bt2_corder_rec_t *)_nrecord;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_store)
+
+    /* Copy user information info native record */
+    nrecord->id = udata->id;
+    nrecord->flags = udata->common.flags;
+    nrecord->corder = udata->common.corder;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5A_dense_btree2_corder_store() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_retrieve
+ *
+ * Purpose:	Retrieve native information from record for v2 B-tree
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_retrieve(void *udata, const void *nrecord)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_retrieve)
+
+    *(H5A_dense_bt2_corder_rec_t *)udata = *(const H5A_dense_bt2_corder_rec_t *)nrecord;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5A_dense_btree2_corder_retrieve() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_compare
+ *
+ * Purpose:	Compare two native information records, according to some key
+ *
+ * Return:	<0 if rec1 < rec2
+ *              =0 if rec1 == rec2
+ *              >0 if rec1 > rec2
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_compare(const void *_bt2_udata, const void *_bt2_rec)
+{
+    const H5A_bt2_ud_common_t *bt2_udata = (const H5A_bt2_ud_common_t *)_bt2_udata;
+    const H5A_dense_bt2_corder_rec_t *bt2_rec = (const H5A_dense_bt2_corder_rec_t *)_bt2_rec;
+    herr_t ret_value;           /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_compare)
+
+    /* Sanity check */
+    HDassert(bt2_udata);
+    HDassert(bt2_rec);
+
+    /* Check creation order value */
+    if(bt2_udata->corder < bt2_rec->corder)
+        ret_value = -1;
+    else if(bt2_udata->corder > bt2_rec->corder)
+        ret_value = 1;
+    else
+        ret_value = 0;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5A_dense_btree2_corder_compare() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_encode
+ *
+ * Purpose:	Encode native information into raw form for storing on disk
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_encode(const H5F_t UNUSED *f, uint8_t *raw, const void *_nrecord)
+{
+    const H5A_dense_bt2_corder_rec_t *nrecord = (const H5A_dense_bt2_corder_rec_t *)_nrecord;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_encode)
+
+    /* Encode the record's fields */
+    UINT64ENCODE(raw, nrecord->id);
+    *raw++ = nrecord->flags;
+    UINT32ENCODE(raw, nrecord->corder)
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5A_dense_btree2_corder_encode() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_decode
+ *
+ * Purpose:	Decode raw disk form of record into native form
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_decode(const H5F_t UNUSED *f, const uint8_t *raw, void *_nrecord)
+{
+    H5A_dense_bt2_corder_rec_t *nrecord = (H5A_dense_bt2_corder_rec_t *)_nrecord;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_decode)
+
+    /* Decode the record's fields */
+    UINT64DECODE(raw, nrecord->id);
+    nrecord->flags = *raw++;
+    UINT32DECODE(raw, nrecord->corder)
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5A_dense_btree2_corder_decode() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5A_dense_btree2_corder_debug
+ *
+ * Purpose:	Debug native form of record
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, February  6, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5A_dense_btree2_corder_debug(FILE *stream, const H5F_t UNUSED *f, hid_t UNUSED dxpl_id,
+    int indent, int fwidth, const void *_nrecord, const void UNUSED *_udata)
+{
+    const H5A_dense_bt2_corder_rec_t *nrecord = (const H5A_dense_bt2_corder_rec_t *)_nrecord;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5A_dense_btree2_corder_debug)
+
+    HDfprintf(stream, "%*s%-*s {%016Hx, %02x, %u}\n", indent, "", fwidth,
+        "Record:",
+        (hsize_t)nrecord->id, (unsigned)nrecord->flags, (unsigned)nrecord->corder);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5A_dense_btree2_corder_debug() */
+
diff --git a/src/H5Adense.c b/src/H5Adense.c
index f227730..a0de2fb 100644
--- a/src/H5Adense.c
+++ b/src/H5Adense.c
@@ -216,6 +216,7 @@ HDfprintf(stderr, "%s: fheap_id_len = %Zu\n", FUNC, fheap_id_len);
 
     /* Create the name index v2 B-tree */
     bt2_rrec_size = 4 +                 /* Name's hash value */
+            4 +                         /* Creation order index */
             1 +                         /* Message flags */
             H5O_FHEAP_ID_LEN;           /* Fractal heap ID */
     if(H5B2_create(f, dxpl_id, H5A_BT2_NAME,
@@ -227,23 +228,21 @@ HDfprintf(stderr, "%s: fheap_id_len = %Zu\n", FUNC, fheap_id_len);
 HDfprintf(stderr, "%s: oh->name_bt2_addr = %a\n", FUNC, oh->name_bt2_addr);
 #endif /* QAK */
 
-/* XXX: fix me */
-#ifdef NOT_YET
     /* Check if we should create a creation order index v2 B-tree */
-    if(linfo->index_corder) {
+    if(oh->flags & H5P_CRT_ORDER_INDEXED) {
         /* Create the creation order index v2 B-tree */
-        bt2_rrec_size = 8 +             /* Creation order value */
+        bt2_rrec_size = 4 +             /* Creation order index */
+                1 +                     /* Message flags */
                 H5O_FHEAP_ID_LEN;       /* Fractal heap ID */
         if(H5B2_create(f, dxpl_id, H5A_BT2_CORDER,
                 (size_t)H5A_CORDER_BT2_NODE_SIZE, bt2_rrec_size,
                 H5A_CORDER_BT2_SPLIT_PERC, H5A_CORDER_BT2_MERGE_PERC,
-                &(linfo->corder_bt2_addr)) < 0)
+                &(oh->corder_bt2_addr)) < 0)
             HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "unable to create v2 B-tree for name index")
 #ifdef QAK
-HDfprintf(stderr, "%s: linfo->corder_bt2_addr = %a\n", FUNC, linfo->corder_bt2_addr);
+HDfprintf(stderr, "%s: oh->corder_bt2_addr = %a\n", FUNC, oh->corder_bt2_addr);
 #endif /* QAK */
     } /* end if */
-#endif /* NOT_YET */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -350,7 +349,7 @@ H5A_dense_open(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, const char *name)
     udata.name = name;
     udata.name_hash = H5_checksum_lookup3(name, HDstrlen(name), 0);
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = H5A_dense_fnd_cb;       /* v2 B-tree comparison callback */
     udata.found_op_data = &ret_value;
 
@@ -484,7 +483,7 @@ H5A_dense_insert(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, H5A_t *attr)
     udata.common.name = attr->name;
     udata.common.name_hash = H5_checksum_lookup3(attr->name, HDstrlen(attr->name), 0);
     udata.common.flags = mesg_flags;
-    udata.common.corder = -1;   /* XXX: None yet */
+    udata.common.corder = attr->crt_idx;
     udata.common.found_op = NULL;
     udata.common.found_op_data = NULL;
     /* udata.id already set */
@@ -493,6 +492,14 @@ H5A_dense_insert(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, H5A_t *attr)
     if(H5B2_insert(f, dxpl_id, H5A_BT2_NAME, oh->name_bt2_addr, &udata) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, FAIL, "unable to insert record into v2 B-tree")
 
+    /* Check if we should create a creation order index v2 B-tree record */
+    if(oh->flags & H5P_CRT_ORDER_INDEXED) {
+        /* Insert the record into the creation order index v2 B-tree */
+        HDassert(H5F_addr_defined(oh->corder_bt2_addr));
+        if(H5B2_insert(f, dxpl_id, H5A_BT2_CORDER, oh->corder_bt2_addr, &udata) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTINSERT, FAIL, "unable to insert record into v2 B-tree")
+    } /* end if */
+
 done:
     /* Release resources */
     if(shared_fheap && H5HF_close(shared_fheap, dxpl_id) < 0)
@@ -656,7 +663,7 @@ H5A_dense_write(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, H5A_t *attr)
     udata.name = attr->name;
     udata.name_hash = H5_checksum_lookup3(attr->name, HDstrlen(attr->name), 0);
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = NULL;
     udata.found_op_data = NULL;
 
@@ -790,7 +797,7 @@ H5A_dense_rename(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, const char *old_name,
     udata.name = old_name;
     udata.name_hash = H5_checksum_lookup3(old_name, HDstrlen(old_name), 0);
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = H5A_dense_fnd_cb;       /* v2 B-tree comparison callback */
     udata.found_op_data = &attr_copy;
 
@@ -1168,7 +1175,7 @@ H5A_dense_remove(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, const char *name)
     udata.name = name;
     udata.name_hash = H5_checksum_lookup3(name, HDstrlen(name), 0);
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = H5A_dense_fnd_cb;       /* v2 B-tree comparison callback */
     udata.found_op_data = &attr_copy;
 
@@ -1253,7 +1260,7 @@ H5A_dense_exists(H5F_t *f, hid_t dxpl_id, const H5O_t *oh, const char *name)
     udata.name = name;
     udata.name_hash = H5_checksum_lookup3(name, HDstrlen(name), 0);
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = NULL;       /* v2 B-tree comparison callback */
     udata.found_op_data = NULL;
 
@@ -1402,7 +1409,7 @@ H5A_dense_delete(H5F_t *f, hid_t dxpl_id, H5O_t *oh)
     udata.name = NULL;
     udata.name_hash = 0;
     udata.flags = 0;
-    udata.corder = -1;   /* XXX: None yet */
+    udata.corder = 0;
     udata.found_op = NULL;       /* v2 B-tree comparison callback */
     udata.found_op_data = NULL;
 
diff --git a/src/H5Apkg.h b/src/H5Apkg.h
index eb2b11f..10aa0ad 100644
--- a/src/H5Apkg.h
+++ b/src/H5Apkg.h
@@ -81,10 +81,19 @@ struct H5A_t {
 /* (Keep 'id' field first so generic record handling in callbacks works) */
 typedef struct H5A_dense_bt2_name_rec_t {
     H5O_fheap_id_t id;                  /* Heap ID for attribute */
-    uint8_t flags;                      /* Message flags for attribute */
+    uint8_t flags;                      /* Object header message flags for attribute */
+    H5O_msg_crt_idx_t corder;           /* 'creation order' field value */
     uint32_t hash;                      /* Hash of 'name' field value */
 } H5A_dense_bt2_name_rec_t;
 
+/* Typedef for native 'creation order' field index records in the v2 B-tree */
+/* (Keep 'id' field first so generic record handling in callbacks works) */
+typedef struct H5A_dense_bt2_corder_rec_t {
+    H5O_fheap_id_t id;                  /* Heap ID for attribute */
+    uint8_t flags;                      /* Object header message flags for attribute */
+    H5O_msg_crt_idx_t corder;           /* 'creation order' field value */
+} H5A_dense_bt2_corder_rec_t;
+
 /*
  * Common data exchange structure for dense attribute storage.  This structure
  * is passed through the v2 B-tree layer to the methods for the objects
@@ -99,7 +108,7 @@ typedef struct H5A_bt2_ud_common_t {
     const char  *name;                  /* Name of attribute to compare      */
     uint32_t    name_hash;              /* Hash of name of attribute to compare */
     uint8_t     flags;                  /* Flags for attribute storage location */
-    int64_t     corder;                 /* Creation order value of attribute to compare */
+    H5O_msg_crt_idx_t corder;           /* Creation order value of attribute to compare */
     H5B2_found_t found_op;              /* Callback when correct attribute is found */
     void        *found_op_data;         /* Callback data when correct attribute is found */
 } H5A_bt2_ud_common_t;
@@ -149,6 +158,9 @@ H5FL_BLK_EXTERN(attr_buf);
 /* The v2 B-tree class for indexing 'name' field on attributes */
 H5_DLLVAR const H5B2_class_t H5A_BT2_NAME[1];
 
+/* The v2 B-tree class for indexing 'creation order' field on attributes */
+H5_DLLVAR const H5B2_class_t H5A_BT2_CORDER[1];
+
 
 /******************************/
 /* Package Private Prototypes */
diff --git a/src/H5B2dbg.c b/src/H5B2dbg.c
index 27db285..d2a392e 100644
--- a/src/H5B2dbg.c
+++ b/src/H5B2dbg.c
@@ -130,8 +130,12 @@ H5B2_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_INDIR_ID ? "H5B2_FHEAP_HUGE_FILT_INDIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_DIR_ID ? "H5B2_FHEAP_HUGE_DIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_DIR_ID ? "H5B2_FHEAP_HUGE_FILT_DIR_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_NAME_ID ? "H5B2_GRP_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_CORDER_ID ? "H5B2_GRP_DENSE_CORDER_ID" :
                   (shared->type->id == H5B2_SOHM_INDEX_ID ? "H5B2_SOHM_INDEX_ID" :
-              "Unknown!")))))));
+                  (shared->type->id == H5B2_ATTR_DENSE_NAME_ID ? "H5B2_ATTR_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_ATTR_DENSE_CORDER_ID ? "H5B2_ATTR_DENSE_CORDER_ID" :
+              "Unknown!")))))))))));
     HDfprintf(stream, "%*s%-*s %Zu\n", indent, "", fwidth,
 	      "Size of node:",
 	      shared->node_size);
@@ -252,8 +256,12 @@ H5B2_int_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_INDIR_ID ? "H5B2_FHEAP_HUGE_FILT_INDIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_DIR_ID ? "H5B2_FHEAP_HUGE_DIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_DIR_ID ? "H5B2_FHEAP_HUGE_FILT_DIR_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_NAME_ID ? "H5B2_GRP_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_CORDER_ID ? "H5B2_GRP_DENSE_CORDER_ID" :
                   (shared->type->id == H5B2_SOHM_INDEX_ID ? "H5B2_SOHM_INDEX_ID" :
-              "Unknown!")))))));
+                  (shared->type->id == H5B2_ATTR_DENSE_NAME_ID ? "H5B2_ATTR_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_ATTR_DENSE_CORDER_ID ? "H5B2_ATTR_DENSE_CORDER_ID" :
+              "Unknown!")))))))))));
     HDfprintf(stream, "%*s%-*s %Zu\n", indent, "", fwidth,
 	      "Size of node:",
 	      shared->node_size);
@@ -374,8 +382,12 @@ H5B2_leaf_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_INDIR_ID ? "H5B2_FHEAP_HUGE_FILT_INDIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_DIR_ID ? "H5B2_FHEAP_HUGE_DIR_ID" :
                   (shared->type->id == H5B2_FHEAP_HUGE_FILT_DIR_ID ? "H5B2_FHEAP_HUGE_FILT_DIR_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_NAME_ID ? "H5B2_GRP_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_GRP_DENSE_CORDER_ID ? "H5B2_GRP_DENSE_CORDER_ID" :
                   (shared->type->id == H5B2_SOHM_INDEX_ID ? "H5B2_SOHM_INDEX_ID" :
-              "Unknown!")))))));
+                  (shared->type->id == H5B2_ATTR_DENSE_NAME_ID ? "H5B2_ATTR_DENSE_NAME_ID" :
+                  (shared->type->id == H5B2_ATTR_DENSE_CORDER_ID ? "H5B2_ATTR_DENSE_CORDER_ID" :
+              "Unknown!")))))))))));
     HDfprintf(stream, "%*s%-*s %Zu\n", indent, "", fwidth,
 	      "Size of node:",
 	      shared->node_size);
diff --git a/src/H5B2private.h b/src/H5B2private.h
index a0e9c3b..35ddfb0 100644
--- a/src/H5B2private.h
+++ b/src/H5B2private.h
@@ -52,6 +52,7 @@ typedef enum H5B2_subid_t {
     H5B2_GRP_DENSE_CORDER_ID,   /* B-tree is for indexing 'creation order' field for "dense" link storage in groups */
     H5B2_SOHM_INDEX_ID,         /* B-tree is an index for shared object header messages */
     H5B2_ATTR_DENSE_NAME_ID,    /* B-tree is for indexing 'name' field for "dense" attribute storage on objects */
+    H5B2_ATTR_DENSE_CORDER_ID,  /* B-tree is for indexing 'creation order' field for "dense" attribute storage on objects */
     H5B2_NUM_BTREE_ID           /* Number of B-tree IDs (must be last)  */
 } H5B2_subid_t;
 
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index d1457df..83a5071 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -92,8 +92,8 @@
         ( 2 /* indexed B-tree internal k */                             \
         + H5F_SIZEOF_ADDR(f) /* base address */                         \
         + H5F_SIZEOF_ADDR(f) /* free space address */                   \
-/*        + H5F_SIZEOF_ADDR(f) /* shared message table address */         \
-/* JAMES        + 2 /* shared message version and number of indexes */          \
+/*        + H5F_SIZEOF_ADDR(f) */ /* shared message table address */         \
+/* JAMES        + 2 */ /* shared message version and number of indexes */          \
         + H5F_SIZEOF_ADDR(f) /* EOF address */                          \
         + H5F_SIZEOF_ADDR(f) /* driver block address */                 \
         + H5G_SIZEOF_ENTRY(f) /* root group ptr */                      \
diff --git a/src/H5Gbtree2.c b/src/H5Gbtree2.c
index ed909c3..d8958fb 100644
--- a/src/H5Gbtree2.c
+++ b/src/H5Gbtree2.c
@@ -275,9 +275,9 @@ for(u = 0; u < H5G_DENSE_FHEAP_ID_LEN; u++)
 #endif /* QAK */
     /* Check hash value */
     if(bt2_udata->name_hash < bt2_rec->hash)
-        HGOTO_DONE(-1)
+        ret_value = (-1);
     else if(bt2_udata->name_hash > bt2_rec->hash)
-        HGOTO_DONE(1)
+        ret_value = 1;
     else {
         H5G_fh_ud_cmp_t fh_udata;       /* User data for fractal heap 'op' callback */
         herr_t status;                  /* Status from fractal heap 'op' routine */
@@ -302,10 +302,9 @@ for(u = 0; u < H5G_DENSE_FHEAP_ID_LEN; u++)
         HDassert(status >= 0);
 
         /* Callback will set comparison value */
-        HGOTO_DONE(fh_udata.cmp)
+        ret_value = fh_udata.cmp;
     } /* end else */
 
-done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5G_dense_btree2_name_compare() */
 
diff --git a/src/H5O.c b/src/H5O.c
index acba9dd..075f6a3 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -697,6 +697,7 @@ H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, hid_t ocpl_id,
         /* Set starting values for attribute info */
         oh->attr_fheap_addr = HADDR_UNDEF;
         oh->name_bt2_addr = HADDR_UNDEF;
+        oh->corder_bt2_addr = HADDR_UNDEF;
     } /* end if */
     else {
         /* Reset unused time fields */
@@ -705,6 +706,7 @@ H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, hid_t ocpl_id,
         /* Reset unused attribute fields */
         oh->attr_fheap_addr = HADDR_UNDEF;
         oh->name_bt2_addr = HADDR_UNDEF;
+        oh->corder_bt2_addr = HADDR_UNDEF;
     } /* end else */
 
     /* Compute total size of initial object header */
diff --git a/src/H5Ocache.c b/src/H5Ocache.c
index 878faf8..f804468 100644
--- a/src/H5Ocache.c
+++ b/src/H5Ocache.c
@@ -304,6 +304,7 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
         H5F_DECODE_LENGTH(f, p, oh->nattrs);
         H5F_addr_decode(f, &p, &(oh->attr_fheap_addr));
         H5F_addr_decode(f, &p, &(oh->name_bt2_addr));
+        H5F_addr_decode(f, &p, &(oh->corder_bt2_addr));
         UINT16DECODE(p, oh->max_attr_crt_idx);
     } /* end if */
     else {
@@ -316,6 +317,7 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
         oh->nattrs = 0;
         oh->attr_fheap_addr = HADDR_UNDEF;
         oh->name_bt2_addr = HADDR_UNDEF;
+        oh->corder_bt2_addr = HADDR_UNDEF;
         oh->max_attr_crt_idx = 0;
     } /* end else */
 
@@ -642,6 +644,7 @@ H5O_assert(oh);
             H5F_ENCODE_LENGTH(f, p, oh->nattrs);
             H5F_addr_encode(f, &p, oh->attr_fheap_addr);
             H5F_addr_encode(f, &p, oh->name_bt2_addr);
+            H5F_addr_encode(f, &p, oh->corder_bt2_addr);
             UINT16ENCODE(p, oh->max_attr_crt_idx);
 
             /* Chunk size */
diff --git a/src/H5Ocopy.c b/src/H5Ocopy.c
index 1592278..b703895 100644
--- a/src/H5Ocopy.c
+++ b/src/H5Ocopy.c
@@ -354,6 +354,7 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
         oh_dst->nattrs = 0;
         oh_dst->attr_fheap_addr = HADDR_UNDEF;
         oh_dst->name_bt2_addr = HADDR_UNDEF;
+        oh_dst->corder_bt2_addr = HADDR_UNDEF;
     } /* end if */
     else {
         oh_dst->nattrs = oh_src->nattrs;
@@ -364,6 +365,7 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
             HDassert(!H5F_addr_defined(oh_src->name_bt2_addr));
             oh_dst->attr_fheap_addr = HADDR_UNDEF;
             oh_dst->name_bt2_addr = HADDR_UNDEF;
+            oh_dst->corder_bt2_addr = HADDR_UNDEF;
         } /* end else */
     } /* end else */
     
diff --git a/src/H5Odbg.c b/src/H5Odbg.c
index 90c9376..50575da 100644
--- a/src/H5Odbg.c
+++ b/src/H5Odbg.c
@@ -320,6 +320,9 @@ H5O_debug_real(H5F_t *f, hid_t dxpl_id, H5O_t *oh, haddr_t addr, FILE *stream, i
         HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
                   "Attribute name index address:",
                   oh->name_bt2_addr);
+        HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
+                  "Attribute creation order index address:",
+                  oh->corder_bt2_addr);
     } /* end if */
 
     HDfprintf(stream, "%*s%-*s %Zu (%Zu)\n", indent, "", fwidth,
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index 3b39640..f7a2a08 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -98,14 +98,15 @@
                 4 +		/*modification time	*/		      \
                 4 +		/*change time		*/		      \
                 4 +		/*birth time		*/		      \
-                2 +		/*max compact attributes	*/	      \
+                2 +		/*max compact attributes */		      \
                 2 +		/*min dense attributes	*/		      \
-                (O)->sizeof_size +	/*# of attributes	*/		      \
-                (O)->sizeof_addr +	/*addr of attribute heap	*/	      \
-                (O)->sizeof_addr +	/*addr of attribute name index	*/	      \
-                2 +		/*max attr. creation index	*/	      \
+                (O)->sizeof_size + /*# of attributes	*/		      \
+                (O)->sizeof_addr + /*addr of attribute heap */		      \
+                (O)->sizeof_addr + /*addr of attribute name index */	      \
+                (O)->sizeof_addr + /*addr of attribute creation order index */ \
+                2 +		/*max attr. creation index */		      \
                 4 +		/*chunk data size	*/		      \
-                H5O_SIZEOF_CHKSUM)	/*checksum size	        */	      \
+                H5O_SIZEOF_CHKSUM) /*checksum size	*/		      \
     )
 
 /*
@@ -245,6 +246,7 @@ struct H5O_t {
     hsize_t     nattrs;                 /* Number of attributes in the group */
     haddr_t     attr_fheap_addr;        /* Address of fractal heap for storing "dense" attributes */
     haddr_t     name_bt2_addr;          /* Address of v2 B-tree for indexing names of attributes */
+    haddr_t     corder_bt2_addr;        /* Address of v2 B-tree for indexing creation order of attributes */
     H5O_msg_crt_idx_t max_attr_crt_idx; /* Maximum attribute creation index used */
 
     /* Message management (stored, encoded in chunks) */
@@ -497,6 +499,7 @@ H5_DLL herr_t H5O_dest(H5F_t *f, H5O_t *oh);
 H5_DLL htri_t H5O_is_attr_empty_test(hid_t oid);
 H5_DLL htri_t H5O_is_attr_dense_test(hid_t oid);
 H5_DLL herr_t H5O_num_attrs_test(hid_t oid, hsize_t *nattrs);
+H5_DLL herr_t H5O_attr_dense_info_test(hid_t oid, hsize_t *name_count, hsize_t *corder_count);
 #endif /* H5O_TESTING */
 
 /* Object header debugging routines */
diff --git a/src/H5Oshmesg.c b/src/H5Oshmesg.c
index 1a39af2..3a02302 100644
--- a/src/H5Oshmesg.c
+++ b/src/H5Oshmesg.c
@@ -251,4 +251,3 @@ H5O_shmesg_debug(H5F_t UNUSED *f, hid_t UNUSED dxpl_id, const void *_mesg, FILE
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5O_shmesg_debug() */
 
-
diff --git a/src/H5Otest.c b/src/H5Otest.c
index b1b0751..e442374 100644
--- a/src/H5Otest.c
+++ b/src/H5Otest.c
@@ -258,3 +258,68 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 }   /* H5O_num_attrs_test() */
 
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5O_attr_dense_info_test
+ PURPOSE
+    Retrieve information about the state of the "dense" storage for attributes
+ USAGE
+    herr_t H5O_attr_dense_info_test(oid, name_count, corder_count)
+        hid_t oid;              IN: Object to check
+        hsize_t *name_count;    OUT: Number of attributes in name index
+        hsize_t *corder_count;  OUT: Number of attributes in creation order index
+ RETURNS
+    Non-negative on success, negative on failure
+ DESCRIPTION
+    Currently, just retrieves the number of attributes in each index and returns
+    them.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+    DO NOT USE THIS FUNCTION FOR ANYTHING EXCEPT TESTING
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5O_attr_dense_info_test(hid_t oid, hsize_t *name_count, hsize_t *corder_count)
+{
+    H5O_t *oh = NULL;           /* Object header */
+    H5O_loc_t *oloc;            /* Pointer to object's location */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_NOAPI(H5O_attr_dense_info_test, FAIL)
+
+    /* Get object location for object */
+    if(NULL == (oloc = H5O_get_loc(oid)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
+
+    /* Get the object header */
+    if(NULL == (oh = H5AC_protect(oloc->file, H5AC_ind_dxpl_id, H5AC_OHDR, oloc->addr, NULL, NULL, H5AC_READ)))
+	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
+
+    /* Check for 'dense' attribute storage file addresses being defined */
+    if(!H5F_addr_defined(oh->attr_fheap_addr))
+        HGOTO_DONE(FAIL)
+    if(!H5F_addr_defined(oh->name_bt2_addr))
+        HGOTO_DONE(FAIL)
+
+    /* Retrieve # of records in name index */
+    if(H5B2_get_nrec(oloc->file, H5AC_ind_dxpl_id, H5A_BT2_NAME, oh->name_bt2_addr, name_count) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTCOUNT, FAIL, "unable to retrieve # of records from name index")
+
+    /* Check if there is a creation order index */
+    if(H5F_addr_defined(oh->corder_bt2_addr)) {
+        /* Retrieve # of records in creation order index */
+        if(H5B2_get_nrec(oloc->file, H5AC_ind_dxpl_id, H5A_BT2_CORDER, oh->corder_bt2_addr, corder_count) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTCOUNT, FAIL, "unable to retrieve # of records from creation order index")
+    } /* end if */
+    else
+        *corder_count = 0;
+
+done:
+    if(oh && H5AC_unprotect(oloc->file, H5AC_ind_dxpl_id, H5AC_OHDR, oloc->addr, oh, H5AC__NO_FLAGS_SET) < 0)
+	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* H5O_attr_dense_info_test() */
+
diff --git a/test/stab.c b/test/stab.c
index 47dbbfe..48e2bb9 100644
--- a/test/stab.c
+++ b/test/stab.c
@@ -426,9 +426,9 @@ lifecycle(hid_t fapl)
     /* Check that the object header is only one chunk and the space has been allocated correctly */
     if(H5Gget_objinfo(gid, ".", FALSE, &obj_stat) < 0) TEST_ERROR
 #ifdef H5_HAVE_LARGE_HSIZET
-    if(obj_stat.ohdr.size != 250) TEST_ERROR
+    if(obj_stat.ohdr.size != 258) TEST_ERROR
 #else /* H5_HAVE_LARGE_HSIZET */
-    if(obj_stat.ohdr.size != 230) TEST_ERROR
+    if(obj_stat.ohdr.size != 238) TEST_ERROR
 #endif /* H5_HAVE_LARGE_HSIZET */
     if(obj_stat.ohdr.free != 0) TEST_ERROR
     if(obj_stat.ohdr.nmesgs != 6) TEST_ERROR
@@ -452,9 +452,9 @@ lifecycle(hid_t fapl)
     /* Check that the object header is still one chunk and the space has been allocated correctly */
     if(H5Gget_objinfo(gid, ".", FALSE, &obj_stat) < 0) TEST_ERROR
 #ifdef H5_HAVE_LARGE_HSIZET
-    if(obj_stat.ohdr.size != 250) TEST_ERROR
+    if(obj_stat.ohdr.size != 258) TEST_ERROR
 #else /* H5_HAVE_LARGE_HSIZET */
-    if(obj_stat.ohdr.size != 230) TEST_ERROR
+    if(obj_stat.ohdr.size != 238) TEST_ERROR
 #endif /* H5_HAVE_LARGE_HSIZET */
     if(obj_stat.ohdr.free != 120) TEST_ERROR
     if(obj_stat.ohdr.nmesgs != 3) TEST_ERROR
diff --git a/test/tattr.c b/test/tattr.c
index c877c37..ff04026 100644
--- a/test/tattr.c
+++ b/test/tattr.c
@@ -2887,6 +2887,174 @@ test_attr_corder_create_compact(hid_t fcpl, hid_t fapl)
 
 /****************************************************************
 **
+**  test_attr_corder_create_dense(): Test basic H5A (attribute) code.
+**      Tests dense attribute storage on objects with attribute creation order info
+**
+****************************************************************/
+static void
+test_attr_corder_create_dense(hid_t fcpl, hid_t fapl)
+{
+    hid_t	fid;		/* HDF5 File ID			*/
+    hid_t	dataset;	/* Dataset ID			*/
+    hid_t	sid;	        /* Dataspace ID			*/
+    hid_t	attr;	        /* Attribute ID			*/
+    hid_t	dcpl;	        /* Dataset creation property list ID */
+    unsigned    max_compact;    /* Maximum # of links to store in group compactly */
+    unsigned    min_dense;      /* Minimum # of links to store in group "densely" */
+    htri_t	is_empty;	/* Are there any attributes? */
+    htri_t	is_dense;	/* Are attributes stored densely? */
+    hsize_t     nattrs;         /* Number of attributes on object */
+    hsize_t     name_count;     /* # of records in name index */
+    hsize_t     corder_count;   /* # of records in creation order index */
+    char	attrname[NAME_BUF_SIZE];        /* Name of attribute */
+    unsigned    u;              /* Local index variable */
+    herr_t	ret;		/* Generic return value		*/
+
+    /* Output message about test being performed */
+    MESSAGE(5, ("Testing Dense Storage of Attributes with Creation Order Info\n"));
+
+    /* Create file */
+    fid = H5Fcreate(FILENAME, H5F_ACC_TRUNC, fcpl, fapl);
+    CHECK(fid, FAIL, "H5Fcreate");
+
+    /* Create dataset creation property list */
+    dcpl = H5Pcreate(H5P_DATASET_CREATE);
+    CHECK(dcpl, FAIL, "H5Pcreate");
+
+    /* Set attribute creation order tracking & indexing for object */
+    ret = H5Pset_attr_creation_order(dcpl, (H5P_CRT_ORDER_TRACKED | H5P_CRT_ORDER_INDEXED));
+    CHECK(ret, FAIL, "H5Pset_attr_creation_order");
+
+    /* Create dataspace for dataset & attributes */
+    sid = H5Screate(H5S_SCALAR);
+    CHECK(sid, FAIL, "H5Screate");
+
+    /* Create a dataset */
+    dataset = H5Dcreate(fid, DSET1_NAME, H5T_NATIVE_UCHAR, sid, dcpl);
+    CHECK(dataset, FAIL, "H5Dcreate");
+
+    /* Check on dataset's attribute storage status */
+    is_empty = H5O_is_attr_empty_test(dataset);
+    VERIFY(is_empty, TRUE, "H5O_is_attr_empty_test");
+    is_dense = H5O_is_attr_dense_test(dataset);
+    VERIFY(is_dense, FALSE, "H5O_is_attr_dense_test");
+
+    /* Query the attribute creation properties */
+    ret = H5Pget_attr_phase_change(dcpl, &max_compact, &min_dense);
+    CHECK(ret, FAIL, "H5Pget_attr_phase_change");
+
+    /* Create several attributes, but keep storage in compact form */
+    for(u = 0; u < max_compact; u++) {
+        /* Create attribute */
+        sprintf(attrname, "attr %02u", u);
+        attr = H5Acreate(dataset, attrname, H5T_NATIVE_UINT, sid, H5P_DEFAULT);
+        CHECK(attr, FAIL, "H5Acreate");
+
+        /* Write data into the attribute */
+        ret = H5Awrite(attr, H5T_NATIVE_UINT, &u);
+        CHECK(ret, FAIL, "H5Awrite");
+
+        /* Close attribute */
+        ret = H5Aclose(attr);
+        CHECK(ret, FAIL, "H5Aclose");
+
+        /* Verify state of object */
+        ret = H5O_num_attrs_test(dataset, &nattrs);
+        CHECK(ret, FAIL, "H5O_num_attrs_test");
+        VERIFY(nattrs, (u + 1), "H5O_num_attrs_test");
+        is_empty = H5O_is_attr_empty_test(dataset);
+        VERIFY(is_empty, FALSE, "H5O_is_attr_empty_test");
+        is_dense = H5O_is_attr_dense_test(dataset);
+        VERIFY(is_dense, FALSE, "H5O_is_attr_dense_test");
+    } /* end for */
+
+    /* Create another attribute, to push into dense storage */
+    sprintf(attrname, "attr %02u", max_compact);
+    attr = H5Acreate(dataset, attrname, H5T_NATIVE_UINT, sid, H5P_DEFAULT);
+    CHECK(attr, FAIL, "H5Acreate");
+
+    /* Write data into the attribute */
+    ret = H5Awrite(attr, H5T_NATIVE_UINT, &u);
+    CHECK(ret, FAIL, "H5Awrite");
+
+    /* Close attribute */
+    ret = H5Aclose(attr);
+    CHECK(ret, FAIL, "H5Aclose");
+
+    /* Verify state of object */
+    ret = H5O_num_attrs_test(dataset, &nattrs);
+    CHECK(ret, FAIL, "H5O_num_attrs_test");
+    VERIFY(nattrs, (max_compact + 1), "H5O_num_attrs_test");
+    is_empty = H5O_is_attr_empty_test(dataset);
+    VERIFY(is_empty, FALSE, "H5O_is_attr_empty_test");
+    is_dense = H5O_is_attr_dense_test(dataset);
+    VERIFY(is_dense, TRUE, "H5O_is_attr_dense_test");
+
+    /* Retrieve & verify # of records in the name & creation order indices */
+    ret = H5O_attr_dense_info_test(dataset, &name_count, &corder_count);
+    CHECK(ret, FAIL, "H5O_attr_dense_info_test");
+    VERIFY(name_count, corder_count, "H5O_attr_dense_info_test");
+
+    /* Close dataspace */
+    ret = H5Sclose(sid);
+    CHECK(ret, FAIL, "H5Sclose");
+
+    /* Close Dataset */
+    ret = H5Dclose(dataset);
+    CHECK(ret, FAIL, "H5Dclose");
+
+    /* Close property list */
+    ret = H5Pclose(dcpl);
+    CHECK(ret, FAIL, "H5Pclose");
+
+    /* Close file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+
+
+    /* Re-open file */
+    fid = H5Fopen(FILENAME, H5F_ACC_RDWR, fapl);
+    CHECK(fid, FAIL, "H5Fopen");
+
+    /* Open dataset created */
+    dataset = H5Dopen(fid, DSET1_NAME);
+    CHECK(dataset, FAIL, "H5Dopen");
+
+    /* Check on dataset's attribute storage status */
+    ret = H5O_num_attrs_test(dataset, &nattrs);
+    CHECK(ret, FAIL, "H5O_num_attrs_test");
+    VERIFY(nattrs, (max_compact + 1), "H5O_num_attrs_test");
+    is_empty = H5O_is_attr_empty_test(dataset);
+    VERIFY(is_empty, FALSE, "H5O_is_attr_empty_test");
+    is_dense = H5O_is_attr_dense_test(dataset);
+    VERIFY(is_dense, TRUE, "H5O_is_attr_dense_test");
+
+    /* Loop through attributes, checking their creation order values */
+    /* (the name index is used, but the creation order value is in the same order) */
+    for(u = 0; u < (max_compact + 1); u++) {
+        H5A_info_t ainfo;           /* Attribute information */
+
+        /* Retrieve information for attribute */
+        sprintf(attrname, "attr %02u", u);
+        ret = H5Aget_info(dataset, attrname, &ainfo);
+        CHECK(ret, FAIL, "H5Aget_info");
+
+        /* Verify creation order of attribute */
+        VERIFY(ainfo.corder_valid, TRUE, "H5Aget_info");
+        VERIFY(ainfo.corder, u, "H5Aget_info");
+    } /* end for */
+
+    /* Close Dataset */
+    ret = H5Dclose(dataset);
+    CHECK(ret, FAIL, "H5Dclose");
+
+    /* Close file */
+    ret = H5Fclose(fid);
+    CHECK(ret, FAIL, "H5Fclose");
+}   /* test_attr_corder_create_dense() */
+
+/****************************************************************
+**
 **  test_attr_shared_write(): Test basic H5A (attribute) code.
 **      Tests writing mix of shared & un-shared attributes in "compact" & "dense" storage
 **
@@ -4487,6 +4655,7 @@ test_attr(void)
         /* Attribute creation order tests */
         test_attr_corder_create_basic(my_fcpl, fapl2);  /* Test creating an object w/attribute creation order info */
         test_attr_corder_create_compact(my_fcpl, fapl2);  /* Test compact attribute storage on an object w/attribute creation order info */
+        test_attr_corder_create_dense(my_fcpl, fapl2);  /* Test dense attribute storage on an object w/attribute creation order info */
     } /* end for */
 
     /* More complex tests with both "new format" and "shared" attributes */
diff --git a/tools/misc/h5debug.c b/tools/misc/h5debug.c
index e9d80a6..061f5f1 100644
--- a/tools/misc/h5debug.c
+++ b/tools/misc/h5debug.c
@@ -24,22 +24,25 @@
  *
  *-------------------------------------------------------------------------
  */
+#define H5A_PACKAGE		/*suppress error about including H5Apkg  */
 #define H5B2_PACKAGE		/*suppress error about including H5B2pkg  */
 #define H5B2_TESTING		/*suppress warning about H5B2 testing funcs*/
 #define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */
 #define H5FS_PACKAGE		/*suppress error about including H5FSpkg  */
+#define H5G_PACKAGE		/*suppress error about including H5Gpkg	  */
 #define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
 #define H5O_PACKAGE		/*suppress error about including H5Opkg	  */
 #define H5SM_PACKAGE		/*suppress error about including H5SMpkg  */
 
 #include "H5private.h"		/* Generic Functions			*/
+#include "H5Apkg.h"		/* Attributes				*/
 #include "H5Bprivate.h"		/* B-trees				*/
 #include "H5B2pkg.h"		/* v2 B-trees				*/
 #include "H5Dprivate.h"		/* Datasets				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fpkg.h"             /* File access				*/
 #include "H5FSpkg.h"		/* File free space			*/
-#include "H5Gprivate.h"		/* Groups				*/
+#include "H5Gpkg.h"		/* Groups				*/
 #include "H5HFpkg.h"		/* Fractal heaps			*/
 #include "H5HGprivate.h"	/* Global Heaps				*/
 #include "H5HLprivate.h"	/* Local Heaps				*/
@@ -234,10 +237,26 @@ main(int argc, char *argv[])
                 status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5HF_BT2_FILT_DIR);
                 break;
 
+            case H5B2_GRP_DENSE_NAME_ID:
+                status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_NAME);
+                break;
+
+            case H5B2_GRP_DENSE_CORDER_ID:
+                status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_CORDER);
+                break;
+
             case H5B2_SOHM_INDEX_ID:
                 status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5SM_INDEX);
                 break;
 
+            case H5B2_ATTR_DENSE_NAME_ID:
+                status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_NAME);
+                break;
+
+            case H5B2_ATTR_DENSE_CORDER_ID:
+                status = H5B2_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_CORDER);
+                break;
+
             default:
                 fprintf(stderr, "Unknown B-tree subtype %u\n", (unsigned)(subtype));
                 HDexit(4);
@@ -281,10 +300,26 @@ main(int argc, char *argv[])
                 status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5HF_BT2_FILT_DIR, extra, (unsigned)extra2, (unsigned)extra3);
                 break;
 
+            case H5B2_GRP_DENSE_NAME_ID:
+                status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_NAME, extra, (unsigned)extra2, (unsigned)extra3);
+                break;
+
+            case H5B2_GRP_DENSE_CORDER_ID:
+                status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_CORDER, extra, (unsigned)extra2, (unsigned)extra3);
+                break;
+
             case H5B2_SOHM_INDEX_ID:
                 status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5SM_INDEX, extra, (unsigned)extra2, (unsigned)extra3);
                 break;
 
+            case H5B2_ATTR_DENSE_NAME_ID:
+                status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_NAME, extra, (unsigned)extra2, (unsigned)extra3);
+                break;
+
+            case H5B2_ATTR_DENSE_CORDER_ID:
+                status = H5B2_int_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_CORDER, extra, (unsigned)extra2, (unsigned)extra3);
+                break;
+
             default:
                 fprintf(stderr, "Unknown B-tree subtype %u\n", (unsigned)(subtype));
                 HDexit(4);
@@ -327,10 +362,26 @@ main(int argc, char *argv[])
                 status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5HF_BT2_FILT_DIR, extra, (unsigned)extra2);
                 break;
 
+            case H5B2_GRP_DENSE_NAME_ID:
+                status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_NAME, extra, (unsigned)extra2);
+                break;
+
+            case H5B2_GRP_DENSE_CORDER_ID:
+                status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5G_BT2_CORDER, extra, (unsigned)extra2);
+                break;
+
             case H5B2_SOHM_INDEX_ID:
                 status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5SM_INDEX, extra, (unsigned)extra2);
                 break;
 
+            case H5B2_ATTR_DENSE_NAME_ID:
+                status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_NAME, extra, (unsigned)extra2);
+                break;
+
+            case H5B2_ATTR_DENSE_CORDER_ID:
+                status = H5B2_leaf_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, H5A_BT2_CORDER, extra, (unsigned)extra2);
+                break;
+
             default:
                 fprintf(stderr, "Unknown B-tree subtype %u\n", (unsigned)(subtype));
                 HDexit(4);