/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:		H5HFcache.c
 *			Feb 24 2006
 *			Quincey Koziol <koziol@ncsa.uiuc.edu>
 *
 * Purpose:		Implement fractal heap metadata cache methods.
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/

#include "H5HFmodule.h"         /* This source code file is part of the H5HF module */


/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions			*/
#include "H5ACprivate.h"	/* Metadata cache			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5HFpkg.h"		/* Fractal heaps			*/
#include "H5MFprivate.h"	/* File memory management		*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5VMprivate.h"	/* Vectors and arrays 			*/
#include "H5WBprivate.h"        /* Wrapped Buffers                      */


/****************/
/* Local Macros */
/****************/

/* Fractal heap format version #'s */
#define H5HF_HDR_VERSION        0               /* Header */
#define H5HF_DBLOCK_VERSION     0               /* Direct block */
#define H5HF_IBLOCK_VERSION     0               /* Indirect block */


/******************/
/* Local Typedefs */
/******************/


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/

/* Local encode/decode routines */
static herr_t H5HF__dtable_encode(H5F_t *f, uint8_t **pp, const H5HF_dtable_t *dtable);
static herr_t H5HF__dtable_decode(H5F_t *f, const uint8_t **pp, H5HF_dtable_t *dtable);

/* Metadata cache (H5AC) callbacks */
static herr_t H5HF__cache_hdr_get_load_size(const void *image_ptr, void *udata, 
    size_t *image_len, size_t *actual_len, 
    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
static htri_t H5HF__cache_hdr_verify_chksum(const void *image_ptr, size_t len, void *udata_ptr);
static void *H5HF__cache_hdr_deserialize(const void *image, size_t len,
    void *udata, hbool_t *dirty); 
static herr_t H5HF__cache_hdr_image_len(const void *thing, size_t *image_len,
    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
static herr_t H5HF__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id,
    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
    unsigned *flags); 
static herr_t H5HF__cache_hdr_serialize(const H5F_t *f, void *image,
    size_t len, void *thing); 
static herr_t H5HF__cache_hdr_free_icr(void *thing);

static herr_t H5HF__cache_iblock_get_load_size(const void *image_ptr, void *udata, 
    size_t *image_len, size_t *actual_len, 
    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
static htri_t H5HF__cache_iblock_verify_chksum(const void *image_ptr, size_t len, void *udata_ptr);
static void *H5HF__cache_iblock_deserialize(const void *image, size_t len,
    void *udata, hbool_t *dirty); 
static herr_t H5HF__cache_iblock_image_len(const void *thing, 
    size_t *image_len, hbool_t *compressed_ptr, 
    size_t *compressed_image_len_ptr);
static herr_t H5HF__cache_iblock_pre_serialize(const H5F_t *f, hid_t dxpl_id,
    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
    unsigned *flags); 
static herr_t H5HF__cache_iblock_serialize(const H5F_t *f, void *image,
    size_t len, void *thing); 
static herr_t H5HF__cache_iblock_notify(H5C_notify_action_t action, void *thing); 
static herr_t H5HF__cache_iblock_free_icr(void *thing);

static herr_t H5HF__cache_dblock_get_load_size(const void *image_ptr, void *udata, 
    size_t *image_len, size_t *actual_len, 
    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
static htri_t H5HF__cache_dblock_verify_chksum(const void *image_ptr, size_t len, void *udata_ptr);
static void *H5HF__cache_dblock_deserialize(const void *image, size_t len,
    void *udata, hbool_t *dirty); 
static herr_t H5HF__cache_dblock_image_len(const void *thing, 
    size_t *image_len, hbool_t *compressed_ptr, 
    size_t *compressed_image_len_ptr);
static herr_t H5HF__cache_dblock_pre_serialize(const H5F_t *f, hid_t dxpl_id,
    void *thing, haddr_t addr, size_t len, size_t compressed_len,
    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
    unsigned *flags); 
static herr_t H5HF__cache_dblock_serialize(const H5F_t *f, void *image,
    size_t len, void *thing); 
static herr_t H5HF__cache_dblock_notify(H5C_notify_action_t action, void *thing);
static herr_t H5HF__cache_dblock_free_icr(void *thing);

/* Debugging Function Prototypes */
#ifndef NDEBUG
static herr_t H5HF__cache_verify_hdr_descendants_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_hdr_t *hdr, hbool_t *clean);
static herr_t H5HF__cache_verify_iblock_descendants_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_indirect_t *iblock, unsigned *iblock_status, hbool_t *clean);
static herr_t H5HF__cache_verify_iblocks_dblocks_clean(H5F_t *f,
    H5HF_indirect_t *iblock, hbool_t *clean, hbool_t *has_dblocks);
static herr_t H5HF__cache_verify_descendant_iblocks_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_indirect_t *iblock, hbool_t *clean, hbool_t *has_iblocks);
#endif /* NDEBUG */


/*********************/
/* Package Variables */
/*********************/

/* H5HF header inherits cache-like properties from H5AC */
const H5AC_class_t H5AC_FHEAP_HDR[1] = {{
    H5AC_FHEAP_HDR_ID,                  /* Metadata client ID */
    "fractal heap header",              /* Metadata client name (for debugging) */
    H5FD_MEM_FHEAP_HDR,                 /* File space memory type for client */
    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
    H5HF__cache_hdr_get_load_size,      /* 'get_load_size' callback */
    H5HF__cache_hdr_verify_chksum, 	/* 'verify_chksum' callback */
    H5HF__cache_hdr_deserialize,        /* 'deserialize' callback */
    H5HF__cache_hdr_image_len,          /* 'image_len' callback */
    H5HF__cache_hdr_pre_serialize,      /* 'pre_serialize' callback */
    H5HF__cache_hdr_serialize,          /* 'serialize' callback */
    NULL,                               /* 'notify' callback */
    H5HF__cache_hdr_free_icr,           /* 'free_icr' callback */
    NULL,                               /* 'clear' callback */
    NULL,                               /* 'fsf_size' callback */
}};

/* H5HF indirect block inherits cache-like properties from H5AC */
const H5AC_class_t H5AC_FHEAP_IBLOCK[1] = {{
    H5AC_FHEAP_IBLOCK_ID,               /* Metadata client ID */
    "fractal heap indirect block",      /* Metadata client name (for debugging) */
    H5FD_MEM_FHEAP_IBLOCK,              /* File space memory type for client */
    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
    H5HF__cache_iblock_get_load_size,   /* 'get_load_size' callback */
    H5HF__cache_iblock_verify_chksum,	/* 'verify_chksum' callback */
    H5HF__cache_iblock_deserialize,     /* 'deserialize' callback */
    H5HF__cache_iblock_image_len,       /* 'image_len' callback */
    H5HF__cache_iblock_pre_serialize,   /* 'pre_serialize' callback */
    H5HF__cache_iblock_serialize,       /* 'serialize' callback */
    H5HF__cache_iblock_notify,          /* 'notify' callback */
    H5HF__cache_iblock_free_icr,        /* 'free_icr' callback */
    NULL,                               /* 'clear' callback */
    NULL,                               /* 'fsf_size' callback */
}};

/* H5HF direct block inherits cache-like properties from H5AC */
const H5AC_class_t H5AC_FHEAP_DBLOCK[1] = {{
    H5AC_FHEAP_DBLOCK_ID,               /* Metadata client ID */
    "fractal heap direct block",        /* Metadata client name (for debugging) */
    H5FD_MEM_FHEAP_DBLOCK,              /* File space memory type for client */
    H5C__CLASS_COMPRESSED_FLAG,         /* Client class behavior flags */
    H5HF__cache_dblock_get_load_size,   /* 'get_load_size' callback */
    H5HF__cache_dblock_verify_chksum,	/* 'verify_chksum' callback */
    H5HF__cache_dblock_deserialize,     /* 'deserialize' callback */
    H5HF__cache_dblock_image_len,       /* 'image_len' callback */
    H5HF__cache_dblock_pre_serialize,   /* 'pre_serialize' callback */
    H5HF__cache_dblock_serialize,       /* 'serialize' callback */
    H5HF__cache_dblock_notify,          /* 'notify' callback */
    H5HF__cache_dblock_free_icr,        /* 'free_icr' callback */
    NULL,                               /* 'clear' callback */
    NULL,                               /* 'fsf_size' callback */
}};


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/

/* Declare a free list to manage heap direct block data to/from disk */
H5FL_BLK_DEFINE(direct_block);



/*-------------------------------------------------------------------------
 * Function:	H5HF__dtable_decode
 *
 * Purpose:	Decodes the metadata for a doubling table
 *
 * Return:	Success:	Pointer to a new fractal heap
 *
 *		Failure:	NULL
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Feb 27 2006
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5HF__dtable_decode(H5F_t *f, const uint8_t **pp, H5HF_dtable_t *dtable)
{
    FUNC_ENTER_STATIC_NOERR

    /* Check arguments */
    HDassert(f);
    HDassert(pp && *pp);
    HDassert(dtable);

    /* Table width */
    UINT16DECODE(*pp, dtable->cparam.width);

    /* Starting block size */
    H5F_DECODE_LENGTH(f, *pp, dtable->cparam.start_block_size);

    /* Maximum direct block size */
    H5F_DECODE_LENGTH(f, *pp, dtable->cparam.max_direct_size);

    /* Maximum heap size (as # of bits) */
    UINT16DECODE(*pp, dtable->cparam.max_index);

    /* Starting # of rows in root indirect block */
    UINT16DECODE(*pp, dtable->cparam.start_root_rows);

    /* Address of table */
    H5F_addr_decode(f, pp, &(dtable->table_addr));

    /* Current # of rows in root indirect block */
    UINT16DECODE(*pp, dtable->curr_root_rows);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__dtable_decode() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__dtable_encode
 *
 * Purpose:	Encodes the metadata for a doubling table
 *
 * Return:	Success:	Pointer to a new fractal heap
 *
 *		Failure:	NULL
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Feb 27 2006
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5HF__dtable_encode(H5F_t *f, uint8_t **pp, const H5HF_dtable_t *dtable)
{
    FUNC_ENTER_STATIC_NOERR

    /* Check arguments */
    HDassert(f);
    HDassert(pp && *pp);
    HDassert(dtable);

    /* Table width */
    UINT16ENCODE(*pp, dtable->cparam.width);

    /* Starting block size */
    H5F_ENCODE_LENGTH(f, *pp, dtable->cparam.start_block_size);

    /* Maximum direct block size */
    H5F_ENCODE_LENGTH(f, *pp, dtable->cparam.max_direct_size);

    /* Maximum heap size (as # of bits) */
    UINT16ENCODE(*pp, dtable->cparam.max_index);

    /* Starting # of rows in root indirect block */
    UINT16ENCODE(*pp, dtable->cparam.start_root_rows);

    /* Address of root direct/indirect block */
    H5F_addr_encode(f, pp, dtable->table_addr);

    /* Current # of rows in root indirect block */
    UINT16ENCODE(*pp, dtable->curr_root_rows);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__dtable_encode() */

/**************************************************/
/* metadata cache callback definitions for header */
/**************************************************/


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_get_load_size()
 *
 * Purpose:	Determine the size of the fractal heap header on disk,
 *		and set *image_len to this value.
 *
 *		This code is based on the old H5HF_cache_hdr_load() routine
 *		that was used with the version 2 metadata cache.  Note the 
 *		use of a dummy header to compute the on disk size of the header.
 *
 *		Note also that the value returned by this function presumes that 
 *		there is no I/O filtering data in the header.  If there is, the 
 *		size reported will be too small, and H5C_load_entry()
 *		will have to make two tries to load the fractal heap header.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_hdr_get_load_size(const void *_image, void *_udata, size_t *image_len, size_t *actual_len,
    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
{
    const uint8_t *image = (const uint8_t *)_image;	/* Pointer into raw data buffer */
    H5HF_hdr_cache_ud_t *udata = (H5HF_hdr_cache_ud_t *)_udata; /* pointer to user data */
    H5HF_hdr_t dummy_hdr; 				/* dummy header -- to compute size */
    unsigned id_len;            /* Size of heap IDs (in bytes) */
    unsigned filter_len;        /* Size of I/O filter information (in bytes) */
    size_t filter_info_size;    /* Size of filter information */
    htri_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(udata);
    HDassert(image_len);

    if(image == NULL) {
	/* Set the internal parameters for the heap */
	dummy_hdr.f = udata->f;
	dummy_hdr.sizeof_size = H5F_SIZEOF_SIZE(udata->f);
	dummy_hdr.sizeof_addr = H5F_SIZEOF_ADDR(udata->f);

	/* Compute the 'base' size of the fractal heap header on disk */
	*image_len = (size_t)H5HF_HEADER_SIZE(&dummy_hdr);

    } else { /* compute actual_len */

	HDassert(actual_len);
	HDassert(*actual_len == *image_len);

	/* Magic number */
	if(HDmemcmp(image, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
	    HGOTO_DONE(FAIL)
	image += H5_SIZEOF_MAGIC;

	/* Version */
	if(*image++ != H5HF_HDR_VERSION)
	    HGOTO_DONE(FAIL)

	/* General heap information */
	UINT16DECODE(image, id_len);              /* Heap ID length */
	UINT16DECODE(image, filter_len);          /* I/O filters' encoded length */

	if(filter_len > 0) {

	    /* Compute the size of the extra filter information */
	    filter_info_size = (size_t)(H5F_SIZEOF_SIZE(udata->f)   /* Size of size for filtered root direct block */
				+ (unsigned)4		/* Size of filter mask for filtered root direct block */
				+ filter_len);         	/* Size of encoded I/O filter info */

	    /* Compute the heap header's size */
	    *actual_len += filter_info_size;
	}

    } /* compute actual_len */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_get_load_size() */


/*-------------------------------------------------------------------------
 * Function:    H5HF__cache_hdr_verify_chksum
 *
 * Purpose:     Verify the computed checksum of the data structure is the
 *              same as the stored chksum.
 *
 * Return:      Success:        TRUE/FALSE
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi; Aug 2015
 *
 *-------------------------------------------------------------------------
 */
static htri_t
H5HF__cache_hdr_verify_chksum(const void *_image, size_t len, void H5_ATTR_UNUSED *_udata)
{
    const uint8_t *image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
    uint32_t stored_chksum;     /* Stored metadata checksum value */
    uint32_t computed_chksum;   /* Computed metadata checksum value */
    htri_t ret_value = TRUE;	/* Return value */

    FUNC_ENTER_STATIC_NOERR

    /* Check arguments */
    HDassert(image);

    /* Get stored and computed checksums */
    H5F_get_checksums(image, len, &stored_chksum, &computed_chksum);

    if(stored_chksum != computed_chksum)
        ret_value = FALSE;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_verify_chksum() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_deserialize
 *
 * Purpose:	Given a buffer containing an on disk image of a fractal heap
 *		header block, allocate an instance of H5HF_hdr_t, load the contents
 *		of the buffer into into the new instance of H5HF_hdr_t, and then
 *		return a pointer to the new instance.
 *
 *		Since H5HF__cache_hdr_get_load_size() reports header on disk size 
 *		base on the assumption that the header contains no I/O filtering 
 *		data, it is possible that the provided image will be too small.
 *
 *		In this case, we DO NOT flag an error when this is discovered.
 *		Instead, we make note of the correct image size, and report 
 *		success.
 *
 *		Since H5HF__cache_hdr_image_len() callback is defined, 
 *		H5C_load_entry() will call H5HF__cache_hdr_image_len() and 
 *		obtain the correct image length.  
 *
 *		Since the H5AC__CLASS_SPECULATIVE_LOAD_FLAG is set, 
 *		H5C_load_entry() will load an image of the correct size, and 
 *		then call this function again to deserialize it.  Before doing 
 *		so, it will also call H5HF__cache_hdr_free_icr() to discard the 
 *		result of the first deserialize call.
 *
 *		Note that the v2 B-tree and free space manager associated 
 *		with the fractal heap (roots stored in the huge_bt2 and fspace 
 *		fields respectively) are not loaded at this time.  As best I can
 *		tell from reviewing the code, they are loaded or created when 
 *		they are accessed.
 *
 * Return:	Success:	Pointer to in core representation
 *		Failure:	NULL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static void *
H5HF__cache_hdr_deserialize(const void *_image, size_t len, void *_udata,
    hbool_t H5_ATTR_UNUSED *dirty)
{
    H5HF_hdr_t          *hdr = NULL;     /* Fractal heap info */
    H5HF_hdr_cache_ud_t *udata = (H5HF_hdr_cache_ud_t *)_udata; /* User data for callback */
    const uint8_t       *image = (const uint8_t *)_image;       /* Pointer into into supplied image */
    size_t              size;           /* Header size */
    uint32_t            stored_chksum;  /* Stored metadata checksum value */
    uint8_t             heap_flags;     /* Status flags for heap */
    void *              ret_value = NULL;       /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(image);
    HDassert(len > 0);
    HDassert(udata);
    HDassert(dirty);

    /* Allocate space for the fractal heap data structure */
    if(NULL == (hdr = H5HF_hdr_alloc(udata->f)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")

    /* Compute the 'base' size of the fractal heap header on disk */
    size = (size_t)H5HF_HEADER_SIZE(hdr);

    /* the size we have just calculated presumes that there is no I/O 
     * filter information in the header.  If there is no filter information,
     * the deserialize operation should succeed.
     *
     * If there is filter information, the first attempt to deserialize 
     * the header will reveal this.  In this case, we will be unable to 
     * deserialize the header as the supplied image will be too small.
     * However, we will make note of the correct size and report success 
     * anyway.  
     *
     * When H5C_load_entry() calls H5HF__cache_hdr_image_len(), we will report 
     * the correct size.  Since the H5C__CLASS_SPECULATIVE_LOAD_FLAG is set,
     * this will prompt H5C_load_entry() to load the correct size image,
     * discard the result of the first attempt at deserialization, and 
     * call this routine a second time to deserialize the correct size 
     * buffer.
     */
    HDassert(size <= len);

    /* Magic number */
    if(HDmemcmp(image, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap header signature")
    image += H5_SIZEOF_MAGIC;

    /* Version */
    if(*image++ != H5HF_HDR_VERSION)
        HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap header version")

    /* General heap information */
    UINT16DECODE(image, hdr->id_len);              /* Heap ID length */
    UINT16DECODE(image, hdr->filter_len);          /* I/O filters' encoded length */

    /* Heap status flags */
    /* (bit 0: "huge" object IDs have wrapped) */
    /* (bit 1: checksum direct blocks) */
    heap_flags = *image++;
    hdr->huge_ids_wrapped = heap_flags & H5HF_HDR_FLAGS_HUGE_ID_WRAPPED;
    hdr->checksum_dblocks = heap_flags & H5HF_HDR_FLAGS_CHECKSUM_DBLOCKS;

    /* "Huge" object information */
    UINT32DECODE(image, hdr->max_man_size);     /* Max. size of "managed" objects */
    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_next_id); /* Next ID to use for "huge" object */
    H5F_addr_decode(udata->f, &image, &hdr->huge_bt2_addr); /* Address of "huge" object tracker B-tree */

    /* "Managed" object free space information */
    H5F_DECODE_LENGTH(udata->f, image, hdr->total_man_free); /* Internal free space in managed direct blocks */
    H5F_addr_decode(udata->f, &image, &hdr->fs_addr);  /* Address of free section header */

    /* Heap statistics */
    H5F_DECODE_LENGTH(udata->f, image, hdr->man_size);
    H5F_DECODE_LENGTH(udata->f, image, hdr->man_alloc_size);
    H5F_DECODE_LENGTH(udata->f, image, hdr->man_iter_off);
    H5F_DECODE_LENGTH(udata->f, image, hdr->man_nobjs);
    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_size);
    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_nobjs);
    H5F_DECODE_LENGTH(udata->f, image, hdr->tiny_size);
    H5F_DECODE_LENGTH(udata->f, image, hdr->tiny_nobjs);

    /* Managed objects' doubling-table info */
    if(H5HF__dtable_decode(hdr->f, &image, &(hdr->man_dtable)) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, NULL, "unable to encode managed obj. doubling table info")

    /* Sanity check */
    /* (allow for checksum not decoded yet) */
    HDassert((size_t)(image - (const uint8_t *)_image) == (size - H5HF_SIZEOF_CHKSUM));

    /* Check for I/O filter information to decode */
    if(hdr->filter_len > 0) {
        size_t filter_info_size;    /* Size of filter information */
        H5O_pline_t *pline;         /* Pipeline information from the header on disk */

        /* Compute the size of the extra filter information */
        filter_info_size = (size_t)(hdr->sizeof_size     /* Size of size for filtered root direct block */
            + (unsigned)4		/* Size of filter mask for filtered root direct block */
            + hdr->filter_len);         /* Size of encoded I/O filter info */

        /* Compute the heap header's size */
        hdr->heap_size = size + filter_info_size;

        if(size == len) 
	    /* we were supplied with too small a buffer -- goto done
             * and let H5C_load_entry() retry with a larger buffer
             */
	    HGOTO_DONE((void *)hdr)

	else
            if((size + filter_info_size) != len)
                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "bad image len")

        /* Decode the size of a filtered root direct block */
        H5F_DECODE_LENGTH(udata->f, image, hdr->pline_root_direct_size);

        /* Decode the filter mask for a filtered root direct block */
        UINT32DECODE(image, hdr->pline_root_direct_filter_mask);

        /* Decode I/O filter information */
        if(NULL == (pline = (H5O_pline_t *)H5O_msg_decode(hdr->f, udata->dxpl_id, NULL, H5O_PLINE_ID, image)))
            HGOTO_ERROR(H5E_HEAP, H5E_CANTDECODE, NULL, "can't decode I/O pipeline filters")

        image += hdr->filter_len;

        /* Copy the information into the header's I/O pipeline structure */
        if(NULL == H5O_msg_copy(H5O_PLINE_ID, pline, &(hdr->pline)))
            HGOTO_ERROR(H5E_HEAP, H5E_CANTCOPY, NULL, "can't copy I/O filter pipeline")

        /* Release the space allocated for the I/O pipeline filters */
        H5O_msg_free(H5O_PLINE_ID, pline);
    } /* end if */
    else
        /* Set the heap header's size */
        hdr->heap_size = size;

    /* checksum verification already done in verify_chksum cb */

    /* Metadata checksum */
    UINT32DECODE(image, stored_chksum);

    /* Sanity check */
    HDassert((size_t)(image - (const uint8_t *)_image) == hdr->heap_size);

    /* Finish initialization of heap header */
    if(H5HF_hdr_finish_init(hdr) < 0)
        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, NULL, "can't finish initializing shared fractal heap header")

    /* Set return value */
    ret_value = (void *)hdr;

done:
    if(!ret_value && hdr)
        if(H5HF_hdr_free(hdr) < 0)
            HDONE_ERROR(H5E_HEAP, H5E_CANTRELEASE, NULL, "unable to release fractal heap header")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_deserialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_image_len
 *
 * Purpose:	Return the actual size of the fractal heap header on 
 *		disk image.  
 *
 *		If the header contains filter information, this size will be 
 *		larger than the value returned by H5HF__cache_hdr_get_load_size().  
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_hdr_image_len(const void *_thing, size_t *image_len,
    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
{
    const H5HF_hdr_t  *hdr = (const H5HF_hdr_t *)_thing;    /* Fractal heap info */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(image_len);

    *image_len = hdr->heap_size;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__cache_hdr_image_len() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_pre_serialize
 *
 * Purpose:	As best I can tell, fractal heap header blocks are always 
 *		allocated in real file space.  Thus this routine simply verifies
 *		this, verifies that the len parameter contains the expected
 *		value, and returns an error if either of these checks fail.
 *
 *		When compiled in debug mode, the function also verifies that all
 *		indirect and direct blocks that are children of the header are 
 *		either clean, or not in the metadata cache.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
    haddr_t addr, size_t len, size_t H5_ATTR_UNUSED compressed_len, 
    haddr_t H5_ATTR_UNUSED *new_addr, size_t H5_ATTR_UNUSED *new_len,
    size_t H5_ATTR_UNUSED *new_compressed_len, unsigned *flags)
{
    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(H5F_addr_defined(addr));
    HDassert(addr == hdr->heap_addr);
    HDassert(new_addr);
    HDassert(new_len);
    HDassert(flags);

#ifndef NDEBUG
{
    hbool_t descendants_clean = TRUE;

    /* Verify that flush dependencies are working correctly.  Do this
     * by verifying that either:
     *
     * 1) the header has a root iblock, and that the root iblock and all
     *    of its children are clean, or
     *
     * 2) The header has a root dblock, which is clean, or
     *
     * 3) The heap is empty, and thus the header has neither a root
     *    iblock no a root dblock.  In this case, the flush ordering
     *    constraint is met by default.
     *
     * Do this with a call to H5HF__cache_verify_hdr_descendants_clean().
     */
    if(H5HF__cache_verify_hdr_descendants_clean((H5F_t *)f, dxpl_id, hdr, &descendants_clean) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify hdr descendants clean.")
    HDassert(descendants_clean);
}
#endif /* NDEBUG */

    if(H5F_IS_TMP_ADDR(f, addr))
        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, FAIL, "addr in temporary space?!?.");

    if(len != hdr->heap_size)
        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, FAIL, "unexpected image len.");

    *flags = 0;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_pre_serialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_serialize
 *
 * Purpose:	Construct the on disk image of the header, and place it in 
 *		the buffer pointed to by image.  Return SUCCEED on success,
 *		and FAIL on failure.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_hdr_serialize(const H5F_t *f, void *_image, size_t len,
    void *_thing)
{
    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
    uint8_t    *image = (uint8_t *)_image;      /* Pointer into raw data buffer */
    uint8_t 	heap_flags;             /* Status flags for heap */
    uint32_t 	metadata_chksum;        /* Computed metadata checksum value */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(image);
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(len == hdr->heap_size);

    /* Set the shared heap header's file context for this operation */
    hdr->f = f;

    /* Magic number */
    HDmemcpy(image, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
    image += H5_SIZEOF_MAGIC;

    /* Version # */
    *image++ = H5HF_HDR_VERSION;

    /* General heap information */
    UINT16ENCODE(image, hdr->id_len);           /* Heap ID length */
    UINT16ENCODE(image, hdr->filter_len);       /* I/O filters' encoded length */

    /* Heap status flags */
    /* (bit 0: "huge" object IDs have wrapped) */
    /* (bit 1: checksum direct blocks) */
    heap_flags = 0;
    heap_flags = (uint8_t)(heap_flags | (hdr->huge_ids_wrapped ? H5HF_HDR_FLAGS_HUGE_ID_WRAPPED : 0));
    heap_flags = (uint8_t)(heap_flags | (hdr->checksum_dblocks ? H5HF_HDR_FLAGS_CHECKSUM_DBLOCKS : 0));
    *image++ = heap_flags;

    /* "Huge" object information */
    UINT32ENCODE(image, hdr->max_man_size);   /* Max. size of "managed" objects */
    H5F_ENCODE_LENGTH(f, image, hdr->huge_next_id); /* Next ID to use for "huge" object */
    H5F_addr_encode(f, &image, hdr->huge_bt2_addr); /* Address of "huge" object tracker B-tree */

    /* "Managed" object free space information */
    H5F_ENCODE_LENGTH(f, image, hdr->total_man_free); /* Internal free space in managed direct blocks */
    H5F_addr_encode(f, &image, hdr->fs_addr); /* Address of free section header */

    /* Heap statistics */
    H5F_ENCODE_LENGTH(f, image, hdr->man_size);
    H5F_ENCODE_LENGTH(f, image, hdr->man_alloc_size);
    H5F_ENCODE_LENGTH(f, image, hdr->man_iter_off);
    H5F_ENCODE_LENGTH(f, image, hdr->man_nobjs);
    H5F_ENCODE_LENGTH(f, image, hdr->huge_size);
    H5F_ENCODE_LENGTH(f, image, hdr->huge_nobjs);
    H5F_ENCODE_LENGTH(f, image, hdr->tiny_size);
    H5F_ENCODE_LENGTH(f, image, hdr->tiny_nobjs);

    /* Managed objects' doubling-table info */
    if(H5HF__dtable_encode(hdr->f, &image, &(hdr->man_dtable)) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "unable to encode managed obj. doubling table info")

    /* Check for I/O filter information to encode */
    if(hdr->filter_len > 0) {
        /* Encode the size of a filtered root direct block */
        H5F_ENCODE_LENGTH(f, image, hdr->pline_root_direct_size);

        /* Encode the filter mask for a filtered root direct block */
        UINT32ENCODE(image, hdr->pline_root_direct_filter_mask);

        /* Encode I/O filter information */
        if(H5O_msg_encode(hdr->f, H5O_PLINE_ID, FALSE, image, &(hdr->pline)) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "can't encode I/O pipeline fiters")
        image += hdr->filter_len;
    } /* end if */

    /* Compute metadata checksum */
    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);

    /* Metadata checksum */
    UINT32ENCODE(image, metadata_chksum);

    /* sanity check */
    HDassert((size_t)(image - (uint8_t *)_image) == len);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_serialize() */

/***************************************/
/* no H5HF__cache_hdr_notify() function */
/***************************************/


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_hdr_free_icr
 *
 * Purpose:	Free the in core representation of the fractal heap header.
 *
 *		This routine frees just the header itself, not the 
 *		associated version 2 B-Tree, the associated Free Space Manager,
 *		nor the indirect/direct block tree that is rooted in the header.
 *
 *		This routine also does not free the file space that may
 *		be allocated to the header.
 *
 * Note:	The metadata cache sets the object's cache_info.magic to
 *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
 *		callback (checked in assert).
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_hdr_free_icr(void *_thing)
{
    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
    herr_t      ret_value = SUCCEED;            /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(hdr->rc == 0);

    if(H5HF_hdr_free(hdr) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "unable to release fractal heap header")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_hdr_free_icr() */

/***********************************************************/
/* metadata cache callback definitions for indirect blocks */
/***********************************************************/


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_get_load_size()
 *
 * Purpose:	Compute the size of the on disk image of the indirect 
 *		block, and place this value in *image_len.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_get_load_size(const void *_image, void *_udata, size_t *image_len, size_t *actual_len,
    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
{
    const uint8_t *image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
    H5HF_iblock_cache_ud_t *udata = (H5HF_iblock_cache_ud_t *)_udata;   /* User data for callback */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(udata);
    HDassert(udata->par_info);
    HDassert(udata->par_info->hdr);
    HDassert(image_len);
   
    if(image == NULL)
	*image_len = (size_t)H5HF_MAN_INDIRECT_SIZE(udata->par_info->hdr, *udata->nrows);
    else {
        HDassert(actual_len);
        HDassert(*actual_len == *image_len);
    } /* end else */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__cache_iblock_get_load_size() */

/***********************************************************/
/* metadata cache callback definitions for indirect blocks */
/***********************************************************/

/*-------------------------------------------------------------------------
 * Function:    H5HF__cache_iblock_verify_chksum
 *
 * Purpose:     Verify the computed checksum of the data structure is the
 *              same as the stored chksum.
 *
 * Return:      Success:        TRUE/FALSE
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi; Aug 2015
 *
 *-------------------------------------------------------------------------
 */
static htri_t
H5HF__cache_iblock_verify_chksum(const void *_image, size_t len, void H5_ATTR_UNUSED *_udata)
{
    const uint8_t *image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
    uint32_t stored_chksum;     /* Stored metadata checksum value */
    uint32_t computed_chksum;   /* Computed metadata checksum value */
    htri_t ret_value = TRUE;	/* Return value */

    FUNC_ENTER_STATIC_NOERR

    /* Check arguments */
    HDassert(image);

    /* Get stored and computed checksums */
    H5F_get_checksums(image, len, &stored_chksum, &computed_chksum);

    if(stored_chksum != computed_chksum)
        ret_value = FALSE;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_verify_chksum() */



/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_deserialize
 *
 * Purpose:	Given a buffer containing the on disk image of the indirect 
 *		block, allocate an instance of H5HF_indirect_t, load the data 
 *		in the buffer into this new instance, and return a pointer to 
 *		it.
 *
 *		As best I can tell, the size of the indirect block image is fully
 *		know before the image is loaded, so this function should succeed
 *		unless the image is corrupt or memory allocation fails.
 *
 * Return:	Success:	Pointer to in core representation
 *		Failure:	NULL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static void *
H5HF__cache_iblock_deserialize(const void *_image, size_t len, void *_udata,
    hbool_t H5_ATTR_UNUSED *dirty)
{
    H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
    H5HF_iblock_cache_ud_t *udata = (H5HF_iblock_cache_ud_t *)_udata; /* User data for callback */
    H5HF_indirect_t     *iblock = NULL; /* Indirect block info */
    const uint8_t       *image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
    haddr_t             heap_addr;      /* Address of heap header in the file */
    uint32_t            stored_chksum;  /* Stored metadata checksum value */
    unsigned            u;              /* Local index variable */
    void *              ret_value = NULL;       /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(image);
    HDassert(udata);
    HDassert(dirty);
    hdr = udata->par_info->hdr;
    HDassert(hdr->f);

    /* Set the shared heap header's file context for this operation */
    hdr->f = udata->f;

    /* Allocate space for the fractal heap indirect block */
    if(NULL == (iblock = H5FL_CALLOC(H5HF_indirect_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")

    /* Share common heap information */
    iblock->hdr = hdr;
    if(H5HF_hdr_incr(hdr) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, NULL, "can't increment reference count on shared heap header")

    /* Set block's internal information */
    iblock->rc = 0;
    iblock->nrows = *udata->nrows;
    iblock->nchildren = 0;

    /* Compute size of indirect block */
    iblock->size = H5HF_MAN_INDIRECT_SIZE(hdr, iblock->nrows);

    /* sanity check */
    HDassert(iblock->size == len);

    /* Magic number */
    if(HDmemcmp(image, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap indirect block signature")
    image += H5_SIZEOF_MAGIC;

    /* Version */
    if(*image++ != H5HF_IBLOCK_VERSION)
        HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap direct block version")

    /* Address of heap that owns this block */
    H5F_addr_decode(udata->f, &image, &heap_addr);
    if(H5F_addr_ne(heap_addr, hdr->heap_addr))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect heap header address for direct block")

    /* Address of parent block */
    iblock->parent = udata->par_info->iblock;
    /* this copy of the parent pointer is needed by the notify callback so */
    /* that it can take down flush dependencies on eviction even if        */
    /* the parent pointer has been nulled out.             JRM -- 5/18/14  */
    iblock->fd_parent = udata->par_info->iblock;
    iblock->par_entry = udata->par_info->entry;
    if(iblock->parent) {
        /* Share parent block */
        if(H5HF_iblock_incr(iblock->parent) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, NULL, "can't increment reference count on shared indirect block")

        /* Set max. # of rows in this block */
        iblock->max_rows = iblock->nrows;
    } /* end if */
    else {
        /* Set max. # of rows in this block */
        iblock->max_rows = hdr->man_dtable.max_root_rows;
    } /* end else */

    /* Offset of heap within the heap's address space */
    UINT64DECODE_VAR(image, iblock->block_off, hdr->heap_off_size);

    /* Allocate & decode child block entry tables */
    HDassert(iblock->nrows > 0);
    if(NULL == (iblock->ents = H5FL_SEQ_MALLOC(H5HF_indirect_ent_t, (size_t)(iblock->nrows * hdr->man_dtable.cparam.width))))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for direct entries")

    if(hdr->filter_len > 0) {
        unsigned dir_rows;   /* Number of direct rows in this indirect block */

        /* Compute the number of direct rows for this indirect block */
        dir_rows = MIN(iblock->nrows, hdr->man_dtable.max_direct_rows);

        /* Allocate indirect block filtered entry array */
        if(NULL == (iblock->filt_ents = H5FL_SEQ_MALLOC(H5HF_indirect_filt_ent_t, (size_t)(dir_rows * hdr->man_dtable.cparam.width))))
            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for block entries")
    } /* end if */
    else
        iblock->filt_ents = NULL;

    for(u = 0; u < (iblock->nrows * hdr->man_dtable.cparam.width); u++) {
        /* Decode child block address */
        H5F_addr_decode(udata->f, &image, &(iblock->ents[u].addr));

        /* Check for heap with I/O filters */
        if(hdr->filter_len > 0) {
            /* Sanity check */
            HDassert(iblock->filt_ents);

            /* Decode extra information for direct blocks */
            if(u < (hdr->man_dtable.max_direct_rows * hdr->man_dtable.cparam.width)) {
                /* Size of filtered direct block */
                H5F_DECODE_LENGTH(udata->f, image, iblock->filt_ents[u].size);

                /* Sanity check */
                /* (either both the address & size are defined or both are
                 *  not defined)
                 */
                HDassert((H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size)
                    || (!H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size == 0));

                /* I/O filter mask for filtered direct block */
                UINT32DECODE(image, iblock->filt_ents[u].filter_mask);
            } /* end if */
        } /* end if */

        /* Count child blocks */
        if(H5F_addr_defined(iblock->ents[u].addr)) {
            iblock->nchildren++;
            iblock->max_child = u;
        } /* end if */
    } /* end for */

    /* Sanity check */
    HDassert(iblock->nchildren);   /* indirect blocks w/no children should have been deleted */

    /* checksum verification already done by verify_chksum cb */

    /* Metadata checksum */
    UINT32DECODE(image, stored_chksum);

    /* Sanity check */
    HDassert((size_t)(image - (const uint8_t *)_image) == iblock->size);

    /* Check if we have any indirect block children */
    if(iblock->nrows > hdr->man_dtable.max_direct_rows) {
        unsigned indir_rows;/* Number of indirect rows in this indirect block */

        /* Compute the number of indirect rows for this indirect block */
        indir_rows = iblock->nrows - hdr->man_dtable.max_direct_rows;

        /* Allocate & initialize child indirect block pointer array */
        if(NULL == (iblock->child_iblocks = H5FL_SEQ_CALLOC(H5HF_indirect_ptr_t, (size_t)(indir_rows * hdr->man_dtable.cparam.width))))
            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "memory allocation failed for block entries")
    } /* end if */
    else
        iblock->child_iblocks = NULL;

    /* Set return value */
    ret_value = (void *)iblock;

done:
    if(!ret_value && iblock)
        if(H5HF_man_iblock_dest(iblock) < 0)
            HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy fractal heap indirect block")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_deserialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_image_len
 *
 * Purpose:	Return the size of the on disk image of the iblock.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_image_len(const void *_thing, size_t *image_len,
    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
{
    const H5HF_indirect_t *iblock = (const H5HF_indirect_t *)_thing;    /* Indirect block info */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(image_len);

    *image_len = iblock->size;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__cache_iblock_image_len() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_pre_serialize
 *
 * Purpose:	The primary objective of this function is to determine if the
 *		indirect block is currently allocated in temporary file space,
 *		and if so, to move it to real file space before the entry is 
 *		serialized.
 *
 *		In debug compiles, this function also verifies that all children
 *		of this indirect block are either clean or are not in cache.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
    haddr_t addr, size_t H5_ATTR_UNUSED len, size_t H5_ATTR_UNUSED compressed_len,
    haddr_t *new_addr, size_t H5_ATTR_UNUSED *new_len,
    size_t H5_ATTR_UNUSED *new_compressed_len, unsigned *flags)
{
    H5HF_hdr_t          *hdr;                   /* Shared fractal heap information */
    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;    /* Indirect block info */
    herr_t      	 ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(iblock->cache_info.size == iblock->size);
    HDassert(H5F_addr_defined(addr));
    HDassert(H5F_addr_eq(iblock->addr, addr));
    HDassert(new_addr);
    HDassert(new_len);
    HDassert(flags);
    hdr = iblock->hdr;
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);

#ifndef NDEBUG
{
    hbool_t 		 descendants_clean = TRUE;
    unsigned 		 iblock_status = 0;

    /* verify that flush dependencies are working correctly.  Do this
     * by verifying that all children of this iblock are clean.
     */
    if(H5AC_get_entry_status(f, iblock->addr, &iblock_status) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get iblock status")

    /* since the current iblock is the guest of honor in a flush, we know
     * that it is locked into the cache for the duration of the call.  Hence
     * there is no need to check to see if it is pinned or protected, or to
     * protect it if it is not.
     */
    if(H5HF__cache_verify_iblock_descendants_clean((H5F_t *)f, dxpl_id, iblock, &iblock_status, &descendants_clean) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify descendants clean.")
    HDassert(descendants_clean);
}
#endif /* NDEBUG */

    /* Check to see if we must re-allocate the iblock from temporary to 
     * normal (AKA real) file space.
     */
    if(H5F_IS_TMP_ADDR(f, addr)) {
        haddr_t iblock_addr;

        /* Allocate 'normal' space for the new indirect block on disk */
        if(HADDR_UNDEF == (iblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_IBLOCK, dxpl_id, (hsize_t)iblock->size)))
            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap indirect block")

        /* Sanity check */
        HDassert(!H5F_addr_eq(iblock->addr, iblock_addr));

        /* Let the metadata cache know the block moved */
        if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_IBLOCK, iblock->addr, iblock_addr) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move indirect block")

        /* Update the internal address for the block */
        iblock->addr = iblock_addr;

        /* Check for root indirect block */
        if(NULL == iblock->parent) {
            /* Update information about indirect block's location */
            hdr->man_dtable.table_addr = iblock_addr;

            /* Mark that heap header was modified */
            if(H5HF_hdr_dirty(hdr) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
        } /* end if */
        else {
            H5HF_indirect_t *par_iblock;    /* Parent indirect block */
            unsigned par_entry;             /* Entry in parent indirect block */

            /* Get parent information */
            par_iblock = iblock->parent;
            par_entry = iblock->par_entry;

            /* Update information about indirect block's location */
            par_iblock->ents[par_entry].addr = iblock_addr;

            /* Mark that parent was modified */
            if(H5HF_iblock_dirty(par_iblock) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
        } /* end if */

	*new_addr = iblock_addr;
        *flags = H5C__SERIALIZE_MOVED_FLAG;
    } /* end if */
    else 
	*flags = 0;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_pre_serialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_serialize
 *
 * Purpose:	Given a pointer to an iblock, and a pointer to a buffer of 
 *		the appropriate size, write the contents of the iblock to the 
 *		buffer in format appropriate for writing to disk.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_serialize(const H5F_t *f, void *_image, size_t len,
    void *_thing)
{
    H5HF_hdr_t 		*hdr;           /* Shared fractal heap information */
    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;     /* Indirect block info */
    uint8_t 		*image = (uint8_t *)_image;     /* Pointer into raw data buffer */
#ifndef NDEBUG
    unsigned 		 nchildren = 0; /* Track # of children */
    size_t		 max_child = 0; /* Track max. child entry used */
#endif /* NDEBUG */
    uint32_t		 metadata_chksum; /* Computed metadata checksum value */
    size_t 		 u;             /* Local index variable */
    herr_t               ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(f);
    HDassert(image);
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(iblock->cache_info.size == iblock->size);
    HDassert(len == iblock->size);

    /* Indirect block must be in 'normal' file space */
    HDassert(!H5F_IS_TMP_ADDR(f, iblock->addr));
    HDassert(H5F_addr_eq(iblock->addr, iblock->cache_info.addr));

    /* Get the pointer to the shared heap header */
    hdr = iblock->hdr;

    /* Set the shared heap header's file context for this operation */
    hdr->f = f;

    /* Magic number */
    HDmemcpy(image, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
    image += H5_SIZEOF_MAGIC;

    /* Version # */
    *image++ = H5HF_IBLOCK_VERSION;

    /* Address of heap header for heap which owns this block */
    H5F_addr_encode(f, &image, hdr->heap_addr);

    /* Offset of block in heap */
    UINT64ENCODE_VAR(image, iblock->block_off, hdr->heap_off_size);

    /* Encode indirect block-specific fields */
    for(u = 0; u < (iblock->nrows * hdr->man_dtable.cparam.width); u++) {
        /* Encode child block address */
        H5F_addr_encode(f, &image, iblock->ents[u].addr);

        /* Check for heap with I/O filters */
        if(hdr->filter_len > 0) {
            /* Sanity check */
            HDassert(iblock->filt_ents);

            /* Encode extra information for direct blocks */
            if(u < (hdr->man_dtable.max_direct_rows * hdr->man_dtable.cparam.width)) {
                /* Sanity check */
                /* (either both the address & size are defined or both are
                 *  not defined)
                 */
                HDassert((H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size) 
                        || (!H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size == 0));

                /* Size of filtered direct block */
                H5F_ENCODE_LENGTH(f, image, iblock->filt_ents[u].size);

                /* I/O filter mask for filtered direct block */
                UINT32ENCODE(image, iblock->filt_ents[u].filter_mask);
            } /* end if */
        } /* end if */

#ifndef NDEBUG
        /* Count child blocks */
        if(H5F_addr_defined(iblock->ents[u].addr)) {
            nchildren++;
            if(u > max_child)
                max_child = u;
        } /* end if */
#endif /* NDEBUG */
    } /* end for */

    /* Compute checksum */
    metadata_chksum = H5_checksum_metadata((uint8_t *)_image, (size_t)(image - (uint8_t *)_image), 0);

    /* Metadata checksum */
    UINT32ENCODE(image, metadata_chksum);

    /* Sanity checks */
    HDassert((size_t)(image - (uint8_t *)_image) == iblock->size);
#ifndef NDEBUG
    HDassert(nchildren == iblock->nchildren);
    HDassert(max_child == iblock->max_child);
#endif /* NDEBUG */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_serialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_notify
 *
 * Purpose:	This function is used to create and destroy flush dependency 
 *		relationships between iblocks and their parents as indirect blocks
 *		are loaded / inserted and evicted from the metadata cache.
 *
 *		In general, the parent will be another iblock, but it may be the 
 *		header if the iblock in question is the root iblock.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_notify(H5C_notify_action_t action, void *_thing)
{
    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;    /* Indirect block info */
    herr_t      	 ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(iblock->hdr);

    if(action == H5AC_NOTIFY_ACTION_BEFORE_EVICT)
        HDassert((iblock->parent == iblock->fd_parent) || ((NULL == iblock->parent) && (iblock->fd_parent)));
    else
        HDassert(iblock->parent == iblock->fd_parent);

    /* further sanity checks */
    if(iblock->parent == NULL) {
        /* Either this is the root iblock, or the parent pointer is     */
        /* invalid.  Since we save a copy of the parent pointer on      */
        /* the insertion event, it doesn't matter if the parent pointer */
        /* is invalid just before eviction.  However, we will not be    */
        /* able to function if it is invalid on the insertion event.    */
        /* Scream and die if this is the case.                          */
        HDassert((action == H5C_NOTIFY_ACTION_BEFORE_EVICT) || (iblock->block_off == 0));

        /* pointer from hdr to root iblock will not be set up unless */
        /* the fractal heap has already pinned the hdr.  Do what     */
        /* sanity checking we can.                                   */
        if((iblock->block_off == 0) && (iblock->hdr->root_iblock_flags & H5HF_ROOT_IBLOCK_PINNED))
           HDassert(iblock->hdr->root_iblock == iblock);
    } /* end if */
    else {
        /* if this is a child iblock, verify that the pointers are */
        /* either uninitialized or set up correctly.               */
        H5HF_indirect_t *par_iblock = iblock->parent;
        unsigned indir_idx;  /* Index in parent's child iblock pointer array */

        /* Sanity check */
        HDassert(par_iblock->child_iblocks);
        HDassert(iblock->par_entry >= (iblock->hdr->man_dtable.max_direct_rows * iblock->hdr->man_dtable.cparam.width));

        /* Compute index in parent's child iblock pointer array */
        indir_idx = iblock->par_entry - (iblock->hdr->man_dtable.max_direct_rows * iblock->hdr->man_dtable.cparam.width);

        /* The pointer to iblock in the parent may not be set yet -- */
        /* verify that it is either NULL, or that it has been set to */
        /* iblock.                                                   */
        HDassert((NULL == par_iblock->child_iblocks[indir_idx]) || (par_iblock->child_iblocks[indir_idx] == iblock));
    } /* end else */

    switch(action) {
        case H5AC_NOTIFY_ACTION_AFTER_INSERT:
        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
            if(iblock->parent) {        /* this is a child iblock */
                /* create flush dependency with parent iblock */
                if(H5AC_create_flush_dependency(iblock->parent, iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDEPEND, FAIL, "unable to create flush dependency")
            } /* end if */
            else {      /* this is the root iblock */
                /* create flush dependency with header */
                if(H5AC_create_flush_dependency(iblock->hdr, iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDEPEND, FAIL, "unable to create flush dependency")
            } /* end else */
            break;

	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
	    /* do nothing */
	    break;

        case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
            if(iblock->fd_parent) {     /* this is a child iblock */
                /* destroy flush dependency with parent iblock */
                if(H5AC_destroy_flush_dependency(iblock->fd_parent, iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTUNDEPEND, FAIL, "unable to destroy flush dependency")
            } /* end if */
            else {      /* this is the root iblock */
                /* destroy flush dependency with header */
                if(H5AC_destroy_flush_dependency(iblock->hdr, iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTUNDEPEND, FAIL, "unable to destroy flush dependency")
            } /* end else */
            break;

        default:
            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unknown action from metadata cache")
            break;
    } /* end switch */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_notify() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_iblock_free_icr
 *
 * Purpose:	Unlink the supplied instance of H5HF_indirect_t from the 
 *		fractal heap and free its memory.
 *
 * Note:	The metadata cache sets the object's cache_info.magic to
 *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
 *		callback (checked in assert).
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_iblock_free_icr(void *thing)
{
    H5HF_indirect_t	*iblock = (H5HF_indirect_t *)thing;     /* Fractal heap indirect block to free */
    herr_t      	 ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(iblock->rc == 0);
    HDassert(iblock->hdr);

    /* Destroy fractal heap indirect block */
    if(H5HF_man_iblock_dest(iblock) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap indirect block")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_iblock_free_icr() */

/*********************************************************/
/* metadata cache callback definitions for direct blocks */
/*********************************************************/


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_get_load_size()
 *
 * Purpose:	Determine the size of the direct block on disk image, and 
 *		return it in *image_len.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_get_load_size(const void *_image, void *_udata, size_t *image_len, size_t *actual_len,
    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr)
{
    const uint8_t *image = (const uint8_t *)_image;                     /* Pointer into raw data buffer */
    const H5HF_dblock_cache_ud_t *udata = (const H5HF_dblock_cache_ud_t *)_udata;    /* User data for callback */
    const H5HF_parent_t *par_info; 	/* Pointer to parent information */
    const H5HF_hdr_t  *hdr;     	/* Shared fractal heap information */
    size_t compressed_size=0;
    hbool_t compressed;

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(udata);
    HDassert(image_len);
    par_info = (const H5HF_parent_t *)(&(udata->par_info));
    HDassert(par_info);
    hdr = par_info->hdr;
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);

    /* Check for I/O filters on this heap */
    if(hdr->filter_len > 0) {

	/* Check for root direct block */
	if(par_info->iblock == NULL) {
	    /* filtered direct block */
	    compressed_size = hdr->pline_root_direct_size;
	} /* end if */
	else {
	    /* filtered direct block */
	    compressed_size = par_info->iblock->filt_ents[par_info->entry].size;
	} /* end else */
    } 

    if(image == NULL) {

	/* depend on I/O filters on this heap */
	*image_len = (hdr->filter_len > 0) ? compressed_size:udata->dblock_size;

    } else { 

	HDassert(actual_len);
	HDassert(*actual_len == *image_len);
	HDassert(compressed_ptr);
	HDassert(compressed_image_len_ptr);

	if(hdr->filter_len > 0) {
	    HDassert(*image_len == compressed_size);
	    compressed = TRUE;
	} else {
	    HDassert(*image_len == udata->dblock_size);
	    compressed = FALSE;
	    compressed_size = 0;
	}

	/* decompressed size */
	*actual_len = udata->dblock_size;
	*compressed_ptr = compressed;
	*compressed_image_len_ptr = compressed_size;
    }
    
    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__cache_dblock_get_load_size() */

/*********************************************************/
/* metadata cache callback definitions for direct blocks */
/*********************************************************/

/*-------------------------------------------------------------------------
 * Function:    H5HF__cache_dblock_verify_chksum
 *
 * Purpose:     Verify the computed checksum of the data structure is the
 *              same as the stored chksum.
 *
 * Return:      Success:        TRUE/FALSE
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi; Aug 2015
 *
 *-------------------------------------------------------------------------
 */
static htri_t
H5HF__cache_dblock_verify_chksum(const void *_image, size_t len, void *_udata)
{
    const uint8_t *image = (const uint8_t *)_image;       		/* Pointer into raw data buffer */
    H5HF_dblock_cache_ud_t *udata = (H5HF_dblock_cache_ud_t *)_udata;   /* User data for callback */
    void *read_buf = NULL;     	/* Pointer to buffer to read in */
    size_t read_size;       	/* Size of filtered direct block to read */
    H5HF_hdr_t  *hdr;           /* Shared fractal heap information */
    H5HF_parent_t *par_info;   	/* Pointer to parent information */
    uint32_t stored_chksum;     /* Stored metadata checksum value */
    uint32_t computed_chksum;   /* Computed metadata checksum value */
    size_t chk_size;       	/* The size for validating checksum */
    uint8_t *chk_p;         	/* Pointer to the area for validating checksum */
    htri_t ret_value = TRUE;	/* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(image);
    HDassert(udata);
    par_info = (H5HF_parent_t *)(&(udata->par_info));
    HDassert(par_info);
    hdr = par_info->hdr;
    HDassert(hdr);

    /* len is the decompressed size of the direct block */

    udata->decompressed = FALSE;
    udata->dblk = NULL;

    /* Get out if data block is not checksummed */
    if(!(hdr->checksum_dblocks))
	HGOTO_DONE(TRUE);

    /* Determine the size on disk */
    if(hdr->filter_len > 0) {

	/* Check for root direct block */
	if(par_info->iblock == NULL) {
	    /* Set up parameters to read filtered direct block */
	    read_size = hdr->pline_root_direct_size;
	} /* end if */
	else {
	    /* Set up parameters to read filtered direct block */
	    read_size = par_info->iblock->filt_ents[par_info->entry].size;
	} /* end else */
    } else
	read_size = len;

    /* Allocate buffer to perform I/O filtering on and copy image into
     * it.  Must do this as H5Z_pipeline() may re-sized the buffer 
     * provided to it.
     */
    if(NULL == (read_buf = H5MM_malloc(read_size)))
	HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "memory allocation failed for pipeline buffer")

    if(hdr->filter_len > 0) {
	size_t nbytes;          /* Number of bytes used in buffer, after applying reverse filters */
	unsigned filter_mask;	/* Excluded filters for direct block */
	H5Z_cb_t filter_cb = {NULL, NULL};  /* Filter callback structure */

	/* Push direct block data through I/O filter pipeline */
	nbytes = read_size;
	filter_mask = udata->filter_mask;
        HDmemcpy(read_buf, image, read_size);

	if(H5Z_pipeline(&(hdr->pline), H5Z_FLAG_REVERSE, &filter_mask, H5Z_ENABLE_EDC, filter_cb, &nbytes, &read_size, &read_buf) < 0)
	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFILTER, FAIL, "output pipeline failed")

	/* Sanity check */
	HDassert(nbytes == len); 
	udata->decompressed = TRUE;

    } else
        HDmemcpy(read_buf, image, read_size);

    /* Decode checksum */
    chk_size = (size_t)(H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr) - H5HF_SIZEOF_CHKSUM);
    chk_p = (uint8_t *)read_buf + chk_size;

    /* Metadata checksum */
    UINT32DECODE(chk_p, stored_chksum);

    chk_p -= H5HF_SIZEOF_CHKSUM;

    /* Reset checksum field, for computing the checksum */
    /* (Casting away const OK - QAK) */
    HDmemset(chk_p, 0, (size_t)H5HF_SIZEOF_CHKSUM);

    /* Compute checksum on entire direct block */
    computed_chksum = H5_checksum_metadata(read_buf, len, 0);

    /* Restore the checksum */
    UINT32ENCODE(chk_p, stored_chksum)

    /* Verify checksum */
    if(stored_chksum != computed_chksum)
	HGOTO_DONE(FALSE);

    /* Save the decompressed data to be used later in deserialize callback */
    if(hdr->filter_len > 0) {

	HDassert(udata->decompressed);
	HDassert(len == udata->dblock_size);
	/* Allocate block buffer */
	if(NULL == (udata->dblk = H5FL_BLK_MALLOC(direct_block, (size_t)len)))
	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")

	/* Copy un-filtered data into block's buffer */
	HDmemcpy(udata->dblk, read_buf, len);
    }

done:
    /* Release the read buffer */
    if(read_buf)
	H5MM_xfree(read_buf);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_verify_chksum() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_deserialize
 *
 * Purpose:	Given a buffer containing the on disk image of a direct
 *		block, allocate an instance of H5HF_direct_t, load the data
 *		in the buffer into this new instance, and return a pointer to
 *		it.
 *
 *		As best I can tell, the size of the direct block image is fully
 *		know before the image is loaded, so this function should succeed
 *		unless the image is corrupt or memory allocation fails.
 *
 * Return:	Success:	Pointer to in core representation
 *		Failure:	NULL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static void *
H5HF__cache_dblock_deserialize(const void *_image, size_t len, void *_udata,
    hbool_t H5_ATTR_UNUSED *dirty)
{
    H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
    H5HF_dblock_cache_ud_t *udata = (H5HF_dblock_cache_ud_t *)_udata;   /* User data for callback */
    H5HF_parent_t       *par_info;      /* Pointer to parent information */
    H5HF_direct_t       *dblock = NULL; /* Direct block info */
    const uint8_t       *image;         /* Pointer into raw data buffer */
    haddr_t             heap_addr;      /* Address of heap header in the file */
    void *              ret_value = NULL;       /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(_image);
    HDassert(udata);
    par_info = (H5HF_parent_t *)(&(udata->par_info));
    HDassert(par_info);
    hdr = par_info->hdr;
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(dirty);

    /* Allocate space for the fractal heap direct block */
    if(NULL == (dblock = H5FL_MALLOC(H5HF_direct_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
    HDmemset(&dblock->cache_info, 0, sizeof(H5AC_info_t));

    /* Set the shared heap header's file context for this operation */
    hdr->f = udata->f;

    /* Share common heap information */
    dblock->hdr = hdr;
    if(H5HF_hdr_incr(hdr) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, NULL, "can't increment reference count on shared heap header")

    /* Set block's internal information */
    dblock->size = udata->dblock_size;
    dblock->file_size = 0;

    /* initialize fields used in serialization */
    dblock->write_buf = NULL;
    dblock->write_size = 0;

    if(udata->dblk && udata->decompressed) { 
	/* direct block is already decompressed in verify_chksum callback */
	HDassert(hdr->filter_len > 0);
	HDassert(len == dblock->size);
	dblock->blk = udata->dblk;
    } else {
	HDassert(udata->dblk == NULL);
	HDassert(!udata->decompressed);

	/* Allocate block buffer */
/* XXX: Change to using free-list factories */
	if(NULL == (dblock->blk = H5FL_BLK_MALLOC(direct_block, (size_t)dblock->size)))
	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
    } 

    /* Check for I/O filters on this heap */
    if(hdr->filter_len > 0) {
	H5Z_cb_t filter_cb = {NULL, NULL};  /* Filter callback structure */
	size_t nbytes;          /* Number of bytes used in buffer, after applying reverse filters */
	void *read_buf;         /* Pointer to buffer to read in */
	size_t read_size;       /* Size of filtered direct block to read */
	unsigned filter_mask;	/* Excluded filters for direct block */

	if(!udata->decompressed) {
	    HDassert(udata->dblk == NULL);

	    /* Check for root direct block */
	    if(par_info->iblock == NULL) {
		/* Set up parameters to read filtered direct block */
		read_size = hdr->pline_root_direct_size;
	    } /* end if */
	    else {
		/* Set up parameters to read filtered direct block */
		read_size = par_info->iblock->filt_ents[par_info->entry].size;
	    } /* end else */
	    HDassert(len == read_size);

	    /* Allocate buffer to perform I/O filtering on and copy image into
	     * it.  Must do this as H5Z_pipeline() may re-sized the buffer 
	     * provided to it.
	     */
	    if(NULL == (read_buf = H5MM_malloc(read_size)))
		HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "memory allocation failed for pipeline buffer")
	    HDmemcpy(read_buf, _image, len);

	    /* Push direct block data through I/O filter pipeline */
	    nbytes = read_size;
	    filter_mask = udata->filter_mask;
	    if(H5Z_pipeline(&(hdr->pline), H5Z_FLAG_REVERSE, &filter_mask, H5Z_ENABLE_EDC, filter_cb, &nbytes, &read_size, &read_buf) < 0)
		HGOTO_ERROR(H5E_HEAP, H5E_CANTFILTER, NULL, "output pipeline failed")

	    /* Sanity check */
	    HDassert(nbytes == dblock->size);

	    /* Copy un-filtered data into block's buffer */
	    HDmemcpy(dblock->blk, read_buf, dblock->size);

	    /* Release the read buffer */
	    H5MM_xfree(read_buf);
	}
    } /* end if */
    else {
        /* copy image to dblock->blk */
        HDassert(dblock->size == len);
        HDmemcpy(dblock->blk, _image, dblock->size);
    } /* end else */

    /* Start decoding direct block */
    image = dblock->blk;

    /* Magic number */
    if(HDmemcmp(image, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap direct block signature")
    image += H5_SIZEOF_MAGIC;

    /* Version */
    if(*image++ != H5HF_DBLOCK_VERSION)
        HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap direct block version")

    /* Address of heap that owns this block (just for file integrity checks) */
    H5F_addr_decode(udata->f, &image, &heap_addr);
    if(H5F_addr_ne(heap_addr, hdr->heap_addr))
        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect heap header address for direct block")

    /* Address of parent block */
    dblock->parent = par_info->iblock;
    dblock->fd_parent = par_info->iblock;
    dblock->par_entry = par_info->entry;
    if(dblock->parent) {
        /* Share parent block */
        if(H5HF_iblock_incr(dblock->parent) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, NULL, "can't increment reference count on shared indirect block")
    } /* end if */

    /* Offset of heap within the heap's address space */
    UINT64DECODE_VAR(image, dblock->block_off, hdr->heap_off_size);

    /* Decode checksum on direct block, if requested */
    if(hdr->checksum_dblocks) {
	uint32_t stored_chksum;         /* Metadata checksum value */

	/* checksum verification already done in verify_chksum cb */

        /* Metadata checksum */
        UINT32DECODE(image, stored_chksum);

    } /* end if */

    /* Sanity check */
    HDassert((size_t)(image - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));

    /* Set return value */
    ret_value = (void *)dblock;

done:
    if(!ret_value && dblock)
        if(H5HF_man_dblock_dest(dblock) < 0)
            HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy fractal heap direct block")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_deserialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_image_len
 *
 * Purpose:	Report the actual size of the direct block image on disk.
 *		Note that this value will probably be incorrect if compression 
 *		is enabled and the entry is dirty.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_image_len(const void *_thing, size_t *image_len, hbool_t *compressed_ptr, size_t *compressed_image_len_ptr)
{
    const H5HF_direct_t    *dblock = (const H5HF_direct_t *)_thing;     /* Direct block info */
    const H5HF_indirect_t  *par_iblock; /* Parent iblock */
    const H5HF_hdr_t  *hdr;             /* Shared fractal heap information */
    hbool_t	      compressed;
    size_t            size;
    size_t	      compressed_size;

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(dblock);
    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
    HDassert(image_len);
    HDassert(compressed_ptr);
    HDassert(compressed_image_len_ptr);

    /* Set up convenience variables */
    hdr = dblock->hdr;
    par_iblock = dblock->parent;

    /* Check for I/O filters on this heap */
    if(hdr->filter_len > 0) {

        /* Filters are enabled, so set compressed to TRUE, and set 
 	 * size equal to the uncompressed size of the direct block.
         * If the data is available, set compressed_size to the compressed
         * size of the direct block -- otherwise set it equal to the 
         * uncompressed size.  
         *
         * We have three possible scenarios here.
         *
         * First, the block may never have been flushed.  In this
         * case, both dblock->file_size and the size stored in the 
         * parent (either the header or the parent iblock) will all 
         * be zero.  In this case, return the uncompressed size 
         * stored in dblock->size as the compressed size.
         *
         * Second, the block may have just been serialized, in which
         * case, dblock->file_size should be zero, and the correct 
         * on disk size should be stored in the parent (again, either
         * the header or the parent iblock as case may be).
         * 
         * Third, we may be in the process of discarding this 
         * dblock without writing it.  In this case, dblock->file_size
         * should be non-zero and have the correct size.  Note that 
         * in this case, the direct block will have been detached,
         * and thus looking up the parent will likely return incorrect
         * data.
         */
        size            = dblock->size;
        compressed      = TRUE;
        compressed_size = dblock->size; /* will overwrite if compressed 
                                         * size is available.
                                         */

        if(dblock->file_size != 0) 
            compressed_size = dblock->file_size;
        else {
            if(par_iblock) {
                unsigned          par_entry;  /* Entry in parent indirect block */

                par_entry = dblock->par_entry;
                compressed_size = par_iblock->filt_ents[par_entry].size;

            } /* end if */
            else {
                compressed_size = hdr->pline_root_direct_size;
            }

            if(compressed_size == 0)
                compressed_size = dblock->size;

        } /* end else */
    } /* end if */
    else {
        size = dblock->size;
        compressed = FALSE;
        compressed_size = 0; /* a convenient, invalid value */
    }

    HDassert(size > 0);

    *image_len                = size;
    *compressed_ptr           = compressed;
    *compressed_image_len_ptr = compressed_size;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5HF__cache_dblock_image_len() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_pre_serialize
 *
 * Purpose:	In principle, the purpose of this function is to determine
 *		the size and location of the disk image of the target direct 
 *		block.  In this case, the uncompressed size of the block is
 *		fixed, but sined the H5C__CLASS_COMPRESSED_FLAG is set, 
 *		we may need to compute and report the compressed size.
 *
 *		This is a bit sticky in the case of a direct block when I/O 
 *		filters are enabled, as the size of the compressed version
 *		of the on disk image is not known until the direct block has 
 *		been run through the filters.  Further, the location of the 
 *		on disk image may change if the compressed size of the image 
 *		changes as well.
 *
 *		To complicate matters further, the direct block may have been 
 *		initially allocated in temporary (AKA imaginary) file space. 
 *		In this case, we must relocate the direct block's on disk 
 *		image to real file space regardless of whether it has changed 
 *		size.
 *
 *		One simplifying factor is the direct block's "blk" field, 
 *		which contains a pointer to a buffer which (with the exception
 *		of a small header) contains the on disk image in uncompressed 
 *		form.
 *
 *		To square this particular circle, this function does 
 *		everything the serialize function usually does, with the 
 *		exception of copying the image into the image buffer provided 
 *		to the serialize function by the metadata cache.  The data to 
 *		copy is provided to the serialize function in a buffer pointed
 *		to by the write_buf field.
 *
 *		If I/O filters are enabled, on exit, 
 *		H5HF__cache_dblock_pre_serialize() sets the write_buf field to 
 *		point to a buffer containing the filtered image of the direct
 *		block.  The serialize function should free this block, and set
 *		the write_buf field to NULL after copying it into the image 
 *		buffer provided by the metadata cache.
 *
 *		If I/O filters are not enabled, this function prepares 
 *		the buffer pointed to by the blk field for copying to the 
 *		image buffer provided by the metadata cache, and sets the 
 *		write_buf field equal to the blk field.  In this case, the 
 *		serialize function should simply set the write_buf field to 
 *		NULL after copying the direct block image into the image 
 *		buffer.
 *
 *		In both of the above cases, the length of the buffer pointed 
 *		to by write_buf is provided in the write_len field.  This 
 *		field must contain 0 on entry to this function, and should 
 *		be set back to 0 at the end of the serialize function.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
    haddr_t addr, size_t len, size_t compressed_len, haddr_t *new_addr, 
    size_t H5_ATTR_UNUSED *new_len, size_t *new_compressed_len, unsigned *flags)
{
    hbool_t 		 at_tmp_addr;  /* Flag to indicate direct block is */
                                       /* at temporary address */
    haddr_t		 dblock_addr;
    H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Direct block info */
    H5HF_indirect_t 	*par_iblock;    /* Parent indirect block */
    unsigned		 par_entry = 0;     /* Entry in parent indirect block */
    void 		*write_buf;     /* Pointer to buffer to write out */
    size_t 		 write_size;    /* Size of buffer to write out */
    uint8_t 		*image;         /* Pointer into raw data buffer */
    unsigned		 dblock_flags = 0;
    herr_t               ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(dblock);
    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
    HDassert(dblock->write_buf == NULL);
    HDassert(dblock->write_size == 0);
    HDassert(dblock->cache_info.size == len);
    HDassert(H5F_addr_defined(addr));
    HDassert(len == dblock->size);
    HDassert(new_addr);
    HDassert(new_compressed_len);
    HDassert(flags);

    /* Set up local variables */
    hdr = dblock->hdr;
    dblock_addr = addr;    /* will update dblock_addr if we move the block */

    /* dblock->size must match dblock->cache_info.size */
    HDassert(dblock->cache_info.size == dblock->size);

    /* Set the shared heap header's file context for this operation */
    hdr->f = (H5F_t *)f;

    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);

    if(dblock->parent) {
	/* this is the common case, in which the direct block is the child 
         * of an indirect block.  Set up the convenience variables we will
         * need if the address and/or compressed size of the on disk image 
         * of the direct block changes, and do some sanity checking in 
         * passing.
         */
        par_iblock = dblock->parent;
	par_entry = dblock->par_entry;

	HDassert(par_iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
	HDassert(par_iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
        HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
    } /* end if */
    else {
	/* the direct block is a root direct block -- just set par_iblock
         * to NULL, as the field will not be used.
         */
	par_iblock = NULL;
    } /* end else */

    at_tmp_addr = H5F_IS_TMP_ADDR(f, addr);

    /* Begin by preping the direct block to be written to disk.  Do
     * this by writing the correct magic number, the dblock version, 
     * the address of the header, the offset of the block in the heap, 
     * and the checksum at the beginning of the block.
     */

    HDassert(dblock->blk);
    image = dblock->blk;

    /* Magic number */
    HDmemcpy(image, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
    image += H5_SIZEOF_MAGIC;

    /* Version # */
    *image++ = H5HF_DBLOCK_VERSION;

    /* Address of heap header for heap which owns this block */
    H5F_addr_encode(f, &image, hdr->heap_addr);

    /* Offset of block in heap */
    UINT64ENCODE_VAR(image, dblock->block_off, hdr->heap_off_size);

    /* Metadata checksum */
    if(hdr->checksum_dblocks) {
        uint32_t metadata_chksum;       /* Computed metadata checksum value */

        /* Clear the checksum field, to compute the checksum */
        HDmemset(image, 0, (size_t)H5HF_SIZEOF_CHKSUM);

        /* Compute checksum on entire direct block */
        metadata_chksum = H5_checksum_metadata(dblock->blk, dblock->size, 0);

        /* Metadata checksum */
        UINT32ENCODE(image, metadata_chksum);
    } /* end if */

    /* at this point, dblock->blk should point to an uncompressed image of 
     * the direct block.  If I/O filters are not enabled, this image should
     * be ready to hand off to the metadata cache.
     */

    /* Sanity check */
    HDassert((size_t)(image - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));

    /* If I/O filters are enabled on this heap, we must run the direct block
     * image through the filters to obtain the image that we will hand off
     * to the metadata cache.
     */

    /* Check for I/O filters on this heap */
    if(hdr->filter_len > 0) {
        H5Z_cb_t filter_cb = {NULL, NULL};  /* Filter callback structure */
        size_t nbytes;                      /* Number of bytes used */
        unsigned filter_mask = 0;           /* Filter mask for block */

        /* Allocate buffer to perform I/O filtering on */
        write_size = dblock->size;

        if(NULL == (write_buf = H5MM_malloc(write_size)))
            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "memory allocation failed for pipeline buffer")
        HDmemcpy(write_buf, dblock->blk, write_size);

        /* Push direct block data through I/O filter pipeline */
        nbytes = write_size;
        if(H5Z_pipeline(&(hdr->pline), 0, &filter_mask, H5Z_ENABLE_EDC, filter_cb, &nbytes, &write_size, &write_buf) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "output pipeline failed")

        /* Use the compressed number of bytes as the size to write */
        write_size = nbytes;

        /* If the size and/or location of the on disk image of the 
         * direct block changes, we must touch up its parent to reflect
         * these changes.  Do this differently depending on whether the
         * direct block's parent is an indirect block or (rarely) the 
         * fractal heap header.  In this case, the direct block is known
         * as a root direct block.
         */

        /* Check for root direct block */
        if(dblock->parent == NULL) {
            hbool_t hdr_changed = FALSE; /* Whether the header info changed */

            /* Sanity check */
            HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
            HDassert(hdr->pline_root_direct_size > 0);

            /* Check if the filter mask changed */
            if(hdr->pline_root_direct_filter_mask != filter_mask) {
                hdr->pline_root_direct_filter_mask = filter_mask;
                hdr_changed = TRUE;
            } /* end if */

            /* verify that the cache's last record of the compressed 
             * size matches the heap's last record.  This value will
             * likely change shortly.
             */
            HDassert(compressed_len == hdr->pline_root_direct_size);

            /* Check if we need to re-size the block on disk */
            if(hdr->pline_root_direct_size != write_size || at_tmp_addr) {
                /* Check if the direct block is NOT currently allocated 
                 * in temp. file space 
                 *
                 * (temp. file space does not need to be freed) 
                 */
                if(!at_tmp_addr) {
                    /* Release direct block's current disk space */
                    if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)hdr->pline_root_direct_size) < 0)
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
                } /* end if */

                /* Allocate space for the compressed direct block */
                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")

                /* Let the metadata cache know, if the block moved */
                if(!H5F_addr_eq(hdr->man_dtable.table_addr, dblock_addr))
                    if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, dblock_addr) < 0)
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")

                /* Update information about compressed direct block's 
                 * location & size 
                 */
                HDassert(hdr->man_dtable.table_addr == addr);
                HDassert(hdr->pline_root_direct_size == compressed_len);
                hdr->man_dtable.table_addr = dblock_addr;
                hdr->pline_root_direct_size = write_size;

                /* Note that heap header was modified */
                hdr_changed = TRUE;
            } /* end if */

            /* Check if heap header was modified */
            if(hdr_changed)
                if(H5HF_hdr_dirty(hdr) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
        } /* end if */
        else { /* the direct block's parent is an indirect block */
            hbool_t par_changed = FALSE;  /* Whether the parent's infochanged */

            /* Sanity check */
            HDassert(par_iblock);
            HDassert(par_iblock->filt_ents[par_entry].size > 0);

            /* Check if the filter mask changed */
            if(par_iblock->filt_ents[par_entry].filter_mask != filter_mask) {
                par_iblock->filt_ents[par_entry].filter_mask = filter_mask;
                par_changed = TRUE;
            } /* end if */

            /* verify that the cache's last record of the compressed 
             * size matches the heap's last record.  This value will
             * likely change shortly.
             */
            HDassert(compressed_len == par_iblock->filt_ents[par_entry].size);

            /* Check if we need to re-size the block on disk */
            if(par_iblock->filt_ents[par_entry].size != write_size || at_tmp_addr) {
                /* Check if the direct block is NOT currently allocated 
                 * in temp. file space 
                 *
                 * (temp. file space does not need to be freed) 
                 */
                if(!at_tmp_addr) {
                    /* Release direct block's current disk space */
                    if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)par_iblock->filt_ents[par_entry].size) < 0)
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
                } /* end if */

                /* Allocate space for the compressed direct block */
                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")

                /* Let the metadata cache know, if the block moved */
                if(!H5F_addr_eq(par_iblock->ents[par_entry].addr, dblock_addr))
                    if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, dblock_addr) < 0)
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")

                /* Update information about compressed direct block's 
                 * location & size 
                 */
                HDassert(par_iblock->ents[par_entry].addr == addr);
                HDassert(par_iblock->filt_ents[par_entry].size == compressed_len);
                par_iblock->ents[par_entry].addr = dblock_addr;
                par_iblock->filt_ents[par_entry].size = write_size;

                /* Note that parent was modified */
                par_changed = TRUE;
            } /* end if */

            /* Check if parent was modified */
            if(par_changed)
                if(H5HF_iblock_dirty(par_iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
        } /* end else */
    } /* end if */
    else {
        /* I/O filters are not enabled -- thus all we need to do is check to 
         * see if the direct block is in temporary (AKA imaginary) file 
         * space, and move it to real file space if it is.
         *
         * As in the I/O filters case above, we will have to touch up the 
         * direct blocks parent if the direct block is relocated.
         *
         * Recall that temporary file space need not be freed, which 
         * simplifies matters slightly.
         */
        write_buf = dblock->blk;
        write_size = dblock->size;

        /* Check to see if we must re-allocate direct block from 'temp.' 
         * to 'normal' file space 
         */
        if(at_tmp_addr) {
            /* Check for root direct block */
            if(NULL == dblock->parent) {
                /* Sanity check */
                HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));

                /* Allocate 'normal' space for the direct block */
                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")

                /* Sanity check */
                HDassert(!H5F_addr_eq(hdr->man_dtable.table_addr, dblock_addr));

                /* Let the metadata cache know the block moved */
                if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, dblock_addr) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")

                /* Update information about direct block's location */
                hdr->man_dtable.table_addr = dblock_addr;

                /* Mark that heap header was modified */
                if(H5HF_hdr_dirty(hdr) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
            } /* end if */
            else { /* the direct block's parent is an indirect block */
                /* Sanity check */
                HDassert(par_iblock);
                HDassert(par_iblock->ents);
                HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));

                /* Allocate 'normal' space for the direct block */
                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")

                /* Sanity check */
                HDassert(!H5F_addr_eq(par_iblock->ents[par_entry].addr, dblock_addr));

                /* Let the metadata cache know the block moved */
                if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, dblock_addr) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")

                /* Update information about direct block's location */
                par_iblock->ents[par_entry].addr = dblock_addr;

                /* Mark that parent was modified */
                if(H5HF_iblock_dirty(par_iblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
            } /* end else */
        } /* end if */
    } /* end else */

    /* At this point, write_buf points to a buffer containing the image 
     * of the direct block that is ready to copy into the image buffer,
     * and write_size contains the length of this buffer. 
     *
     * Also, if image size or address has changed, the direct block's
     * parent has been modified to reflect the change.
     *
     * Now, make note of the pointer and length of the above buffer for
     * use by the serialize function.
     */
    dblock->write_buf = (uint8_t *)write_buf;
    dblock->write_size = write_size;

    /* finally, pass data back to the metadata cache as appropriate */
    if(!H5F_addr_eq(addr, dblock_addr)) {
        dblock_flags |= H5C__SERIALIZE_MOVED_FLAG;
        *new_addr = dblock_addr;
    } /* end if */

    if((hdr->filter_len > 0) && (compressed_len != write_size)) {
        dblock_flags |= H5C__SERIALIZE_COMPRESSED_FLAG;
        *new_compressed_len = write_size;
    } /* end if */

    *flags = dblock_flags;

    /* final sanity check */
    HDassert(dblock->write_buf);
    HDassert(dblock->write_size > 0);

done:
    /* discard the write buf if we have an error */
    if(write_buf && (write_buf != dblock->blk) && (dblock->write_buf == NULL))
	H5MM_xfree(write_buf);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_pre_serialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_serialize
 *
 * Purpose:	In principle, this function is supposed to construct the on 
 *		disk image of the direct block, and place that image in the 
 *		image buffer provided by the metadata cache.
 *
 *		However, since there are cases in which the pre_serialize 
 *		function has to construct the on disk image to determine its size 
 *		and address, this function simply copies the image prepared by
 *		the pre-serialize function into the supplied image buffer, and 
 *		discards a buffer if necessary.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_serialize(const H5F_t *f, void *image, size_t len,
    void *_thing)
{
    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Direct block info */
    herr_t               ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC_NOERR

    /* Sanity checks */
    HDassert(f);
    HDassert(image);
    HDassert(len > 0);
    HDassert(dblock);
    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
    HDassert((dblock->blk != dblock->write_buf) || (dblock->cache_info.size == dblock->size));
    HDassert(dblock->write_buf);
    HDassert(dblock->write_size > 0);
    HDassert((dblock->blk != dblock->write_buf) || (dblock->write_size == dblock->size));
    HDassert(dblock->write_size == len);

    /* Copy the image from *(dblock->write_buf) to *image */
    HDmemcpy(image, dblock->write_buf, dblock->write_size);

    /* Free *(dblock->write_buf) if it was allocated by the 
     * pre-serialize function 
     */
    if(dblock->write_buf != dblock->blk)
        H5MM_xfree(dblock->write_buf);

    /* Reset the write_buf and write_size fields */
    dblock->write_buf = NULL;
    dblock->write_size = 0;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_serialize() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_notify
 *
 * Purpose:	Setup / takedown flush dependencies as direct blocks
 *		are loaded / inserted and evicted from the metadata cache.
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_notify(H5C_notify_action_t action, void *_thing)
{
    H5HF_direct_t 	*dblock = (H5HF_direct_t *)_thing;      /* Fractal heap direct block */
    herr_t 		 ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(dblock);
    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
    HDassert(dblock->hdr);
    HDassert((dblock->fd_parent) ||
             ((dblock->hdr->man_dtable.curr_root_rows == 0) && (dblock->block_off == (hsize_t)0)));

    switch(action) {
        case H5AC_NOTIFY_ACTION_AFTER_INSERT:
        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
            HDassert(dblock->parent == dblock->fd_parent);
            if(dblock->parent) {        /* this is a leaf dblock */
                /* create flush dependency with parent iblock */
                if(H5AC_create_flush_dependency(dblock->parent, dblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDEPEND, FAIL, "unable to create flush dependency")
            } /* end if */
            else {      /* this is a root dblock */
                /* create flush dependency with header */
                if(H5AC_create_flush_dependency(dblock->hdr, dblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDEPEND, FAIL, "unable to create flush dependency")
            } /* end else */
            break;

	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
	    /* do nothing */
	    break;

        case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
            HDassert((dblock->parent == dblock->fd_parent) ||
                     ((NULL == dblock->parent) && (dblock->fd_parent)));
            if(dblock->fd_parent) {     /* this is a leaf dblock */
                /* destroy flush dependency with parent iblock */
                if(H5AC_destroy_flush_dependency(dblock->fd_parent, dblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTUNDEPEND, FAIL, "unable to destroy flush dependency")
            } /* end if */
            else {      /* this is a root dblock */
                /* destroy flush dependency with header */
                if(H5AC_destroy_flush_dependency(dblock->hdr, dblock) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTUNDEPEND, FAIL, "unable to destroy flush dependency")
            } /* end else */
            break;

        default:
            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unknown action from metadata cache")
            break;
    } /* end switch */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_notify() */


/*-------------------------------------------------------------------------
 * Function:	H5HF__cache_dblock_free_icr
 *
 * Purpose:	Free the in core memory allocated to the supplied direct
 *		block.
 *
 * Note:	The metadata cache sets the object's cache_info.magic to
 *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
 *		callback (checked in assert).
 *
 * Return:	Success:	SUCCEED
 *		Failure:	FAIL
 *
 * Programmer:	John Mainzer
 *		6/21/14
 *
 *-------------------------------------------------------------------------
 */
static herr_t 
H5HF__cache_dblock_free_icr(void *_thing)
{
    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Fractal heap direct block */
    herr_t      	 ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(dblock);
    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);

    /* Destroy fractal heap direct block */
    if(H5HF_man_dblock_dest(dblock) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap direct block")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5HF__cache_dblock_free_icr() */


/*------------------------------------------------------------------------
 * Function:	H5HF__cache_verify_hdr_descendants_clean
 *
 * Purpose:	Sanity checking routine that verifies that all indirect 
 *		and direct blocks that are descendants of the supplied 
 *		instance of H5HF_hdr_t are clean.  Set *clean to 
 *		TRUE if this is the case, and to FALSE otherwise.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	John Mainzer
 *		5/25/14
 *
 *-------------------------------------------------------------------------
 */
#ifndef NDEBUG
static herr_t
H5HF__cache_verify_hdr_descendants_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_hdr_t * hdr, hbool_t *clean)
{
    haddr_t	hdr_addr;               /* Address of header */
    unsigned	hdr_status = 0;         /* Header cache entry status */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(hdr);
    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
    HDassert(clean);
    hdr_addr = hdr->cache_info.addr;
    HDassert(hdr_addr == hdr->heap_addr);

    if(H5AC_get_entry_status(f, hdr_addr, &hdr_status) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get hdr status")
    HDassert(hdr_status & H5AC_ES__IN_CACHE);

    /* We have three basic scenarios we have to deal with:
     *
     * The first, and most common case, is that there is a root iblock.  
     * In this case we need to verify that the root iblock and all its 
     * children are clean.
     *
     * The second, and much less common case, is that in which the 
     * the fractal heap contains only one direct block, which is 
     * pointed to by hdr->man_dtable.table_addr.  In this case, all we 
     * need to do is verify that the root direct block is clean.
     *
     * Finally, it is possible that the fractal heap is empty, and 
     * has neither a root indirect block nor a root direct block.
     * In this case, we have nothing to do.
     */

    /* There are two ways in which we can arrive at the first scenario.
     *
     * By far the most common is when hdr->root_iblock contains a pointer
     * to the root iblock -- in this case the root iblock is almost certainly 
     * pinned, although we can't count on that.
     *
     * However, it is also possible that there is a root iblock that 
     * is no longer pointed to by the header.  In this case, the on 
     * disk address of the iblock will be in hdr->man_dtable.table_addr
     * and hdr->man_dtable.curr_root_rows will contain a positive value.
     *
     * Since the former case is far and away the most common, we don't 
     * worry too much about efficiency in the second case.
     */
    if(hdr->root_iblock ||
             ((hdr->man_dtable.curr_root_rows > 0) &&
               (HADDR_UNDEF != hdr->man_dtable.table_addr))) {
        H5HF_indirect_t *root_iblock = hdr->root_iblock;
        haddr_t		root_iblock_addr;
        unsigned	root_iblock_status = 0;
        hbool_t		root_iblock_in_cache;

        /* make note of the on disk address of the root iblock */
        if(root_iblock == NULL)
	    /* hdr->man_dtable.table_addr must contain address of root
             * iblock.  Check to see if it is in cache.  If it is, 
             * protect it and put its address in root_iblock.
             */
	    root_iblock_addr = hdr->man_dtable.table_addr;
        else
	    root_iblock_addr = root_iblock->addr;

	/* get the status of the root iblock */
	HDassert(root_iblock_addr != HADDR_UNDEF);
        if(H5AC_get_entry_status(f, root_iblock_addr, &root_iblock_status) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get root iblock status")

	root_iblock_in_cache = ( (root_iblock_status & H5AC_ES__IN_CACHE) != 0);
	HDassert(root_iblock_in_cache || (root_iblock == NULL));

	if(!root_iblock_in_cache) /* we are done */
	    *clean = TRUE;
	else if(root_iblock_status & H5AC_ES__IS_DIRTY)
	    *clean = FALSE;
	else { /* must examine children */
            hbool_t	unprotect_root_iblock = FALSE;

	    /* At this point, the root iblock may be pinned, protected,
	     * both, or neither, and we may or may not have a pointer
	     * to root iblock in memory.  
	     *
	     * Before we call H5HF__cache_verify_iblock_descendants_clean(),
	     * we must ensure that the root iblock is either pinned or 
	     * protected or both, and that we have a pointer to it.  
	     * Do this as follows:
	     */
	    if(root_iblock == NULL) {   /* we don't have ptr to root iblock */
		if(0 == (root_iblock_status & H5AC_ES__IS_PROTECTED)) {
		    /* just protect the root iblock -- this will give us
		     * the pointer we need to proceed, and ensure that 
		     * it is locked into the metadata cache for the 
		     * duration.
		     *
		     * Note that the udata is only used in the load callback.
                     * While the fractal heap makes heavy use of the udata
                     * in this case, since we know that the entry is in cache,
                     * we can pass NULL udata.
		     */
                    if(NULL == (root_iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
                    unprotect_root_iblock = TRUE;
		} /* end if */
                else {
		    /* the root iblock is protected, and we have no
		     * legitimate way of getting a pointer to it.
		     *
		     * We square this circle by using the 
		     * H5AC_get_entry_ptr_from_addr() to get the needed
		     * pointer.
		     *
		     * WARNING: This call should be used only in debugging
                     *          routines, and it should be avoided there when
                     *          possible.
                     *
                     *          Further, if we ever multi-thread the cache,
                     *          this routine will have to be either discarded
                     *          or heavily re-worked.
                     *
                     *          Finally, keep in mind that the entry whose
                     *          pointer is obtained in this fashion may not
                     *          be in a stable state.
                     *
                     * Assuming that the flush dependency code is working
                     * as it should, the only reason for the root iblock to
                     * be unpinned is if none of its children are in cache.
                     * This unfortunately means that if it is protected and
                     * not pinned, the fractal heap is in the process of loading
                     * or inserting one of its children.  The obvious implication
                     * is that there is a significant chance that the root
                     * iblock is in an unstable state.
                     *
                     * All this suggests that using H5AC_get_entry_ptr_from_addr()
		     * to obtain the pointer to the protected root iblock is 
		     * questionable here.  However, since this is test/debugging 
		     * code, I expect that we will use this approach until it 
		     * causes problems, or we think of a better way.
                     */
                    if(H5AC_get_entry_ptr_from_addr(f, root_iblock_addr, (void **)(&root_iblock)) < 0)
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "H5AC_get_entry_ptr_from_addr() failed.")
                    HDassert(root_iblock);
		} /* end else */
	    } /* end if */
            else {      /* root_iblock != NULL */
		/* we have the pointer to the root iblock.  Protect it 
		 * if it is neither pinned nor protected -- otherwise we 
		 * are ready to go.
		 */
                H5HF_indirect_t *   iblock = NULL;

                if(((root_iblock_status & H5AC_ES__IS_PINNED) == 0) &&
                        ((root_iblock_status & H5AC_ES__IS_PROTECTED) == 0)) {
                    /* the root iblock is neither pinned nor protected -- hence
                     * we must protect it before we proceed
                     *
                     * Note that the udata is only used in the load callback.
                     * While the fractal heap makes heavy use of the udata
                     * in this case, since we know that the entry is in cache,
                     * we can pass NULL udata.
                     */
                    if(NULL == (iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                        HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
                    unprotect_root_iblock = TRUE;
                    HDassert(iblock == root_iblock);
		} /* end if */
	    } /* end else */

            /* at this point, one way or another, the root iblock is locked
             * in memory for the duration of the call.  Do some sanity checks,
	     * and then call H5HF__cache_verify_iblock_descendants_clean().
             */
            HDassert(hdr->root_iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
            HDassert(hdr->root_iblock->cache_info.type == H5AC_FHEAP_IBLOCK);

            if(H5HF__cache_verify_iblock_descendants_clean(f, dxpl_id, root_iblock, &root_iblock_status, clean) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify root iblock & descendants clean.")

            /* unprotect the root indirect block if required */
            if(unprotect_root_iblock) {
                HDassert(root_iblock);
                if(H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, root_iblock, H5AC__NO_FLAGS_SET) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "H5AC_unprotect() faild.")
            } /* end if */
        } /* end else */
    } /* end if */
    else if((hdr->man_dtable.curr_root_rows == 0) &&
		(HADDR_UNDEF != hdr->man_dtable.table_addr)) {
        haddr_t		root_dblock_addr;
        unsigned	root_dblock_status = 0;
        hbool_t		in_cache;
        hbool_t		type_ok;

	/* this is scenario 2 -- we have a root dblock */
	root_dblock_addr = hdr->man_dtable.table_addr;
        if(H5AC_get_entry_status(f, root_dblock_addr, &root_dblock_status) < 0)
            HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get root dblock status")

	if(root_dblock_status & H5AC_ES__IN_CACHE) {
	    if(H5AC_verify_entry_type(f, root_dblock_addr, &H5AC_FHEAP_DBLOCK[0], &in_cache, &type_ok) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't check dblock type")
	    HDassert(in_cache);
	    if(!type_ok)
		HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "root dblock addr doesn't refer to a dblock?!?")

            /* If a root dblock is in cache, it must have a flush
             * dependency relationship with the header, and it
             * may not be the parent in any flush dependency
             * relationship.
             *
             * We don't test this fully, but we will verify that
             * the root iblock is a child in some flush dependency
             * relationship.
             */
            if(0 == (root_dblock_status & H5AC_ES__IS_FLUSH_DEP_CHILD))
                HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "root dblock in cache and not a flush dep child.")
            if(0 != (root_dblock_status & H5AC_ES__IS_FLUSH_DEP_PARENT))
                HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "root dblock in cache and is a flush dep parent.")

	    *clean = ! (root_dblock_status & H5AC_ES__IS_DIRTY);
	} /* end if */
        else    /* root dblock not in cache */
	    *clean = TRUE;
    } /* end else-if */
    else
	/* this is scenario 3 -- the fractal heap is empty, and we 
	 * have nothing to do. 
	 */
	*clean = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HF__cache_verify_hdr_descendants_clean() */
#endif /* NDEBUG */


/*------------------------------------------------------------------------
 * Function:	H5HF__cache_verify_iblock_descendants_clean
 *
 * Purpose:	Sanity checking routine that verifies that all indirect 
 *		and direct blocks that are decendents of the supplied 
 *		instance of H5HF_indirect_t are clean.  Set *clean 
 *		to TRUE if this is the case, and to FALSE otherwise.
 *
 *		In passing, the function also does a cursory check to 
 *		spot any obvious errors in the flush dependency setup.  
 *		If any problems are found, the function returns failure.  
 *		Note that these checks are not exhaustive, thus passing 
 *		them does not mean that the flush dependencies are 
 *		correct -- only that there is nothing obviously wrong
 *		with them.
 *
 *		WARNING:  At its top level call, this function is 
 *		intended to be called from H5HF_cache_iblock_flush(), 
 *		and thus presumes that the supplied indirect block 
 *		is in cache.  Any other use of this function and 
 *		its descendants must insure that this assumption is 
 *		met.
 *
 *		Note that this function and 
 *		H5HF__cache_verify_descendant_iblocks_clean() are 
 *		recursive co-routines.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	John Mainzer
 *		5/25/14
 *
 *-------------------------------------------------------------------------
 */
#ifndef NDEBUG
static herr_t
H5HF__cache_verify_iblock_descendants_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_indirect_t *iblock, unsigned *iblock_status, hbool_t *clean)
{
    hbool_t	has_dblocks = FALSE;
    hbool_t	has_iblocks = FALSE;
    herr_t      ret_value = SUCCEED;      /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(iblock_status);
    HDassert(clean);
    HDassert(*clean);

    if((*clean) && H5HF__cache_verify_iblocks_dblocks_clean(f, iblock, clean, &has_dblocks) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify dblocks clean.")

    if((*clean) && H5HF__cache_verify_descendant_iblocks_clean(f, dxpl_id, iblock, clean, &has_iblocks) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify iblocks clean.")

    if((NULL == iblock_status) && H5AC_get_entry_status(f, iblock->addr, iblock_status) < 0)
        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get iblock status")

    /* verify that flush dependency setup is plausible */
    if(0 == (*iblock_status & H5AC_ES__IS_FLUSH_DEP_CHILD))
	HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "iblock is not a flush dep child.")
    if(((has_dblocks || has_iblocks)) && (0 == (*iblock_status & H5AC_ES__IS_FLUSH_DEP_PARENT)))
	HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "iblock has children and is not a flush dep parent.")
    if(((has_dblocks || has_iblocks)) && (0 == (*iblock_status & H5AC_ES__IS_PINNED)))
	HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "iblock has children and is not pinned.")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HF__cache_verify_iblock_descendants_clean() */
#endif /* NDEBUG */


/*------------------------------------------------------------------------
 * Function:	H5HF__cache_verify_iblocks_dblocks_clean
 *
 * Purpose:	Sanity checking routine that attempts to verify that all
 *		direct blocks pointed to by the supplied indirect block
 *		are either clean, or not in the cache.
 *
 *		In passing, the function also does a cursory check to 
 *		spot any obvious errors in the flush dependency setup.  
 *		If any problems are found, the function returns failure.  
 *		Note that these checks are not exhaustive, thus passing 
 *		them does not mean that the flush dependencies are 
 *		correct -- only that there is nothing obviously wrong
 *		with them.
 *
 *		WARNING:  This function presumes that the supplied 
 *		iblock is in the cache, and will not be removed 
 *		during the call.  Caller must ensure that this is 
 *		the case before the call.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	John Mainzer
 *		5/25/14
 *
 *-------------------------------------------------------------------------
 */
#ifndef NDEBUG
static herr_t
H5HF__cache_verify_iblocks_dblocks_clean(H5F_t *f, H5HF_indirect_t *iblock, 
    hbool_t *clean, hbool_t *has_dblocks)
{
    unsigned	num_direct_rows;
    unsigned	max_dblock_index;
    unsigned    i;
    herr_t      ret_value = SUCCEED;      /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(clean);
    HDassert(*clean);
    HDassert(has_dblocks);

    i = 0;
    num_direct_rows = MIN(iblock->nrows, iblock->hdr->man_dtable.max_direct_rows);
    HDassert(num_direct_rows <= iblock->nrows);
    max_dblock_index = (num_direct_rows * iblock->hdr->man_dtable.cparam.width) - 1;
    while((*clean) && (i <= max_dblock_index)) {
        haddr_t     dblock_addr;

        dblock_addr = iblock->ents[i].addr;
	if(H5F_addr_defined(dblock_addr)) {
            hbool_t	in_cache;
            hbool_t	type_ok;

	    if(H5AC_verify_entry_type(f, dblock_addr, &H5AC_FHEAP_DBLOCK[0], &in_cache, &type_ok) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't check dblock type")

	    if(in_cache) { /* dblock is in cache */
                unsigned 	dblock_status = 0;

		if(!type_ok)
		    HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "dblock addr doesn't refer to a dblock?!?")

                if(H5AC_get_entry_status(f, dblock_addr, &dblock_status) < 0)
                    HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get dblock status")
                HDassert(dblock_status & H5AC_ES__IN_CACHE);

	        *has_dblocks = TRUE;
                if(dblock_status & H5AC_ES__IS_DIRTY)
		    *clean = FALSE;

	        /* If a child dblock is in cache, it must have a flush 
                 * dependency relationship with this iblock, and it 
                 * may not be the parent in any flush dependency 
                 * relationship.  
                 * 
                 * We don't test this fully, but we will verify that 
                 * the child iblock is a child in some flush dependency 
                 * relationship.
                 */
	        if(0 == (dblock_status & H5AC_ES__IS_FLUSH_DEP_CHILD))
		    HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "dblock in cache and not a flush dep child.")
	        
                if(0 != (dblock_status & H5AC_ES__IS_FLUSH_DEP_PARENT)) 
		    HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "dblock in cache and is a flush dep parent.")
   
            } /* end if */
        } /* end if */

        i++;
    } /* end while */
    
done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HF__cache_verify_iblocks_dblocks_clean() */
#endif /* NDEBUG */


/*------------------------------------------------------------------------
 * Function:	H5HF__cache_verify_descendant_iblocks_clean
 *
 * Purpose:	Sanity checking routine that attempts to verify that all
 *		direct blocks pointed to by the supplied indirect block
 *		are either clean, or not in the cache.
 *
 *		In passing, the function also does a cursory check to 
 *		spot any obvious errors in the flush dependency setup.  
 *		If any problems are found, the function returns failure.  
 *		Note that these checks are not exhaustive, thus passing 
 *		them does not mean that the flush dependencies are 
 *		correct -- only that there is nothing obviously wrong
 *		with them.
 *
 *		WARNING:  This function presumes that the supplied 
 *		iblock is in the cache, and will not be removed 
 *		during the call.  Caller must ensure that this is 
 *		the case before the call.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	John Mainzer
 *		5/25/14
 *
 *-------------------------------------------------------------------------
 */
#ifndef NDEBUG
static herr_t
H5HF__cache_verify_descendant_iblocks_clean(H5F_t *f, hid_t dxpl_id,
    H5HF_indirect_t *iblock, hbool_t *clean, hbool_t *has_iblocks)
{
    unsigned	      first_iblock_index;
    unsigned	      last_iblock_index;
    unsigned	      num_direct_rows;
    unsigned	      i;
    herr_t            ret_value = SUCCEED;      /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity checks */
    HDassert(f);
    HDassert(iblock);
    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
    HDassert(clean);
    HDassert(*clean);
    HDassert(has_iblocks);
    num_direct_rows = MIN(iblock->nrows, iblock->hdr->man_dtable.max_direct_rows);
    HDassert(num_direct_rows <= iblock->nrows);

    first_iblock_index = num_direct_rows * iblock->hdr->man_dtable.cparam.width;
    last_iblock_index = (iblock->nrows * iblock->hdr->man_dtable.cparam.width) - 1;

    i = first_iblock_index;
    while((*clean) && (i <= last_iblock_index)) {
        haddr_t           child_iblock_addr = iblock->ents[i].addr;

	if(H5F_addr_defined(child_iblock_addr)) {
            unsigned 	      child_iblock_status = 0;

            if(H5AC_get_entry_status(f, child_iblock_addr, &child_iblock_status) < 0)
                HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get iblock status")

	    if(child_iblock_status & H5AC_ES__IN_CACHE) {
	        *has_iblocks = TRUE;
                if(child_iblock_status & H5AC_ES__IS_DIRTY)
		    *clean = FALSE;

                /* if the child iblock is in cache and *clean is TRUE, 
                 * we must continue to explore down the fractal heap tree
                 * structure to verify that all descendant blocks are either
                 * clean, or not in the metadata cache.  We do this with a 
                 * recursive call to 
		 * H5HF__cache_verify_iblock_descendants_clean().
		 * However, we can't make this call unless the child iblock
                 * is somehow locked into the cache -- typically via either 
 		 * pinning or protecting.
                 *
                 * If the child iblock is pinned, we can look up its pointer
                 * on the current iblock's pinned child iblock list, and 
                 * and use that pointer in the recursive call.
                 *
                 * If the entry is unprotected and unpinned, we simply
                 * protect it.
                 *
		 * If, however, the the child iblock is already protected, 
                 * but not pinned, we have a bit of a problem, as we have 
		 * no legitimate way of looking up its pointer in memory.
		 *
		 * To solve this problem, I have added a new metadata cache
		 * call to obtain the pointer.  
		 *
		 * WARNING: This call should be used only in debugging 
		 * 	    routines, and it should be avoided there when 
		 *	    possible.  
		 *
		 *          Further, if we ever multi-thread the cache, 
		 *	    this routine will have to be either discarded 
		 *	    or heavily re-worked.
		 *
		 *	    Finally, keep in mind that the entry whose 
		 *	    pointer is obtained in this fashion may not 
		 *          be in a stable state.  
		 *
		 * Assuming that the flush dependency code is working 
		 * as it should, the only reason for the child entry to 
		 * be unpinned is if none of its children are in cache.
		 * This unfortunately means that if it is protected and 
		 * not pinned, the fractal heap is in the process of loading
		 * or inserting one of its children.  The obvious implication
		 * is that there is a significant chance that the child 
		 * iblock is in an unstable state.
		 *
		 * All this suggests that using the new call to obtain the 
		 * pointer to the protected child iblock is questionable 
		 * here.  However, since this is test/debugging code, I
		 * expect that we will use this approach until it causes
		 * problems, or we think of a better way.
                 */
                if(*clean) {
                    H5HF_indirect_t *child_iblock = NULL;
                    hbool_t unprotect_child_iblock = FALSE;

		    if(0 == (child_iblock_status & H5AC_ES__IS_PINNED)) {
			/* child iblock is not pinned */
			if(0 == (child_iblock_status & H5AC_ES__IS_PROTECTED)) {
			    /* child iblock is unprotected, and unpinned */
			    /* protect it.  Note that the udata is only  */
			    /* used in the load callback.  While the     */
			    /* fractal heap makes heavy use of the udata */
			    /* in this case, since we know that the      */
			    /* entry is in cache, we can pass NULL udata */

			    if(NULL == (child_iblock = (H5HF_indirect_t *) H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, child_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                                HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
			    unprotect_child_iblock = TRUE;
			} /* end if */
                        else {
			    /* child iblock is protected -- use             */
			    /* H5AC_get_entry_ptr_from_addr() to get a      */
			    /* pointer to the entry.  This is very slimy -- */
			    /* come up with a better solution.              */
			    if(H5AC_get_entry_ptr_from_addr(f, child_iblock_addr, (void **)(&child_iblock)) < 0)
                                HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "H5AC_get_entry_ptr_from_addr() faild.")
			    HDassert(child_iblock);
			} /* end else */
		    } /* end if */
                    else {
			/* child iblock is pinned -- look it up in the */
			/* parent iblocks child_iblocks array.         */
			HDassert(iblock->child_iblocks);
			child_iblock = iblock->child_iblocks[i - first_iblock_index];
		    } /* end else */

		    /* At this point, one way or another we should have 
                     * a pointer to the child iblock.  Verify that we 
                     * that we have the correct one.
                     */
		    HDassert(child_iblock);
    		    HDassert(child_iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
    		    HDassert(child_iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
		    HDassert(child_iblock->addr == child_iblock_addr);

		    /* now make the recursive call */
		    if(H5HF__cache_verify_iblock_descendants_clean(f, dxpl_id, child_iblock, &child_iblock_status, clean) < 0)
        		HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify child iblock clean.")

		    /* if we protected the child iblock, unprotect it now */
		    if(unprotect_child_iblock) {
			if(H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_IBLOCK, child_iblock_addr, child_iblock, H5AC__NO_FLAGS_SET) < 0)
                            HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "H5AC_unprotect() faild.")

                    } /* end if */
                } /* end if */
            } /* end if */
        } /* end if */

        i++;
    } /* end while */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5HF__cache_verify_descendant_iblocks_clean() */
#endif /* NDEBUG */

