summaryrefslogtreecommitdiffstats
path: root/src/H5Fsuper_cache.c
blob: e62cc474dfefd92dba1a84dd6e23ec960ed2a0a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * 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 COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:		H5Fsuper_cache.c
 *
 * Purpose:		Implement file superblock & driver info metadata cache methods
 *
 *-------------------------------------------------------------------------
 */

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

#include "H5Fmodule.h" /* This source code file is part of the H5F module */
#define H5G_FRIEND     /*suppress error about including H5Gpkg	  */

/***********/
/* Headers */
/***********/
#include "H5private.h"   /* Generic Functions			*/
#include "H5Eprivate.h"  /* Error handling		  	*/
#include "H5Fpkg.h"      /* File access				*/
#include "H5FDprivate.h" /* File drivers				*/
#include "H5FLprivate.h" /* Free Lists                           */
#include "H5Gpkg.h"      /* Groups		  		*/
#include "H5Iprivate.h"  /* IDs			  		*/
#include "H5MMprivate.h" /* Memory management                    */
#include "H5Pprivate.h"  /* Property lists			*/

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

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

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

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

/* Metadata cache (H5AC) callbacks */
static herr_t H5F__cache_superblock_get_initial_load_size(void *udata, size_t *image_len);
static herr_t H5F__cache_superblock_get_final_load_size(const void *image_ptr, size_t image_len, void *udata,
                                                        size_t *actual_len);
static htri_t H5F__cache_superblock_verify_chksum(const void *image_ptr, size_t len, void *udata_ptr);
static void  *H5F__cache_superblock_deserialize(const void *image, size_t len, void *udata, bool *dirty);
static herr_t H5F__cache_superblock_image_len(const void *thing, size_t *image_len);
static herr_t H5F__cache_superblock_serialize(const H5F_t *f, void *image, size_t len, void *thing);
static herr_t H5F__cache_superblock_free_icr(void *thing);

static herr_t H5F__cache_drvrinfo_get_initial_load_size(void *udata, size_t *image_len);
static herr_t H5F__cache_drvrinfo_get_final_load_size(const void *image_ptr, size_t image_len, void *udata,
                                                      size_t *actual_len);
static void  *H5F__cache_drvrinfo_deserialize(const void *image, size_t len, void *udata, bool *dirty);
static herr_t H5F__cache_drvrinfo_image_len(const void *thing, size_t *image_len);
static herr_t H5F__cache_drvrinfo_serialize(const H5F_t *f, void *image, size_t len, void *thing);
static herr_t H5F__cache_drvrinfo_free_icr(void *thing);

/* Local encode/decode routines */
static herr_t H5F__superblock_prefix_decode(H5F_super_t *sblock, const uint8_t **image_ref, size_t len,
                                            const H5F_superblock_cache_ud_t *udata, bool extend_eoa);
static herr_t H5F__drvrinfo_prefix_decode(H5O_drvinfo_t *drvinfo, char *drv_name, const uint8_t **image_ref,
                                          size_t len, H5F_drvrinfo_cache_ud_t *udata, bool extend_eoa);

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

/* H5F superblock inherits cache-like properties from H5AC */
const H5AC_class_t H5AC_SUPERBLOCK[1] = {{
    H5AC_SUPERBLOCK_ID,                          /* Metadata client ID */
    "Superblock",                                /* Metadata client name (for debugging) */
    H5FD_MEM_SUPER,                              /* File space memory type for client */
    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,           /* Client class behavior flags */
    H5F__cache_superblock_get_initial_load_size, /* 'get_initial_load_size' callback */
    H5F__cache_superblock_get_final_load_size,   /* 'get_final_load_size' callback */
    H5F__cache_superblock_verify_chksum,         /* 'verify_chksum' callback */
    H5F__cache_superblock_deserialize,           /* 'deserialize' callback */
    H5F__cache_superblock_image_len,             /* 'image_len' callback */
    NULL,                                        /* 'pre_serialize' callback */
    H5F__cache_superblock_serialize,             /* 'serialize' callback */
    NULL,                                        /* 'notify' callback */
    H5F__cache_superblock_free_icr,              /* 'free_icr' callback */
    NULL,                                        /* 'fsf_size' callback */
}};

/* H5F driver info block inherits cache-like properties from H5AC */
const H5AC_class_t H5AC_DRVRINFO[1] = {{
    H5AC_DRVRINFO_ID,                          /* Metadata client ID */
    "Driver info block",                       /* Metadata client name (for debugging) */
    H5FD_MEM_SUPER,                            /* File space memory type for client */
    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,         /* Client class behavior flags */
    H5F__cache_drvrinfo_get_initial_load_size, /* 'get_initial_load_size' callback */
    H5F__cache_drvrinfo_get_final_load_size,   /* 'get_final_load_size' callback */
    NULL,                                      /* 'verify_chksum' callback */
    H5F__cache_drvrinfo_deserialize,           /* 'deserialize' callback */
    H5F__cache_drvrinfo_image_len,             /* 'image_len' callback */
    NULL,                                      /* 'pre_serialize' callback */
    H5F__cache_drvrinfo_serialize,             /* 'serialize' callback */
    NULL,                                      /* 'notify' callback */
    H5F__cache_drvrinfo_free_icr,              /* 'free_icr' callback */
    NULL,                                      /* 'fsf_size' callback */
}};

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

/* Declare extern the free list to manage the H5F_super_t struct */
H5FL_EXTERN(H5F_super_t);

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

/*-------------------------------------------------------------------------
 * Function:    H5F__superblock_prefix_decode
 *
 * Purpose:     Decode a superblock prefix
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__superblock_prefix_decode(H5F_super_t *sblock, const uint8_t **image_ref, size_t len,
                              const H5F_superblock_cache_ud_t *udata, bool extend_eoa)
{
    const uint8_t *image     = (const uint8_t *)*image_ref; /* Pointer into raw data buffer */
    const uint8_t *end       = image + len - 1;             /* Pointer to end of buffer */
    htri_t         ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(sblock);
    assert(image_ref);
    assert(image);
    assert(udata);
    assert(udata->f);

    /* Skip over signature (already checked when locating the superblock) */
    if (H5_IS_BUFFER_OVERFLOW(image, H5F_SIGNATURE_LEN, end))
        HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
    image += H5F_SIGNATURE_LEN;

    /* Superblock version */
    if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
        HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
    sblock->super_vers = *image++;
    if (sblock->super_vers > HDF5_SUPERBLOCK_VERSION_LATEST)
        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad superblock version number");

    /* Size check */
    if (((size_t)(image - (const uint8_t *)*image_ref)) != H5F_SUPERBLOCK_FIXED_SIZE)
        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad superblock (fixed) size");

    /* Determine the size of addresses & size of offsets, for computing the
     * variable-sized portion of the superblock.
     */
    if (sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
        if (H5_IS_BUFFER_OVERFLOW(image, 6, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
        sblock->sizeof_addr = image[4];
        sblock->sizeof_size = image[5];
    }
    else {
        if (H5_IS_BUFFER_OVERFLOW(image, 2, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
        sblock->sizeof_addr = image[0];
        sblock->sizeof_size = image[1];
    }

    if (sblock->sizeof_addr != 2 && sblock->sizeof_addr != 4 && sblock->sizeof_addr != 8 &&
        sblock->sizeof_addr != 16 && sblock->sizeof_addr != 32)
        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number in an address");
    if (sblock->sizeof_size != 2 && sblock->sizeof_size != 4 && sblock->sizeof_size != 8 &&
        sblock->sizeof_size != 16 && sblock->sizeof_size != 32)
        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad byte number for object size");

    /* Check for extending the EOA for the file */
    if (extend_eoa) {
        size_t variable_size; /* Variable size of superblock */

        /* Determine the size of the variable-length part of the superblock */
        variable_size =
            (size_t)H5F_SUPERBLOCK_VARLEN_SIZE(sblock->super_vers, sblock->sizeof_addr, sblock->sizeof_size);
        if (variable_size == 0)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "variable size can't be zero");

        /* Make certain we can read the variable-sized portion of the superblock */
        if (H5F__set_eoa(udata->f, H5FD_MEM_SUPER, (haddr_t)(H5F_SUPERBLOCK_FIXED_SIZE + variable_size)) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed");
    }

    /* Update the image buffer pointer */
    *image_ref = image;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__superblock_prefix_decode() */

/*-------------------------------------------------------------------------
 * Function:    H5F__drvrinfo_prefix_decode
 *
 * Purpose:     Decode a driver info prefix
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__drvrinfo_prefix_decode(H5O_drvinfo_t *drvrinfo, char *drv_name, const uint8_t **image_ref, size_t len,
                            H5F_drvrinfo_cache_ud_t *udata, bool extend_eoa)
{
    const uint8_t *image = (const uint8_t *)*image_ref; /* Pointer into raw data buffer */
    const uint8_t *end   = image + len - 1;             /* Pointer to end of buffer */
    unsigned       drv_vers;                            /* Version of driver info block */
    herr_t         ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(drvrinfo);
    assert(image_ref);
    assert(image);
    assert(udata);
    assert(udata->f);

    /* Version number */
    if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
        HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
    drv_vers = *image++;
    if (drv_vers != HDF5_DRIVERINFO_VERSION_0)
        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "bad driver information block version number");

    /* Reserved bytes */
    if (H5_IS_BUFFER_OVERFLOW(image, 3, end))
        HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
    image += 3;

    /* Driver info size */
    if (H5_IS_BUFFER_OVERFLOW(image, 4, end))
        HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
    UINT32DECODE(image, drvrinfo->len);

    /* Driver name and/or version */
    if (drv_name) {
        if (H5_IS_BUFFER_OVERFLOW(image, 8, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
        H5MM_memcpy(drv_name, (const char *)image, (size_t)8);
        drv_name[8] = '\0';
        image += 8; /* advance past name/version */
    }

    /* Extend the EOA if required so that we can read the complete driver info block */
    if (extend_eoa) {
        haddr_t eoa;     /* Current EOA for the file */
        haddr_t min_eoa; /* Minimum EOA needed for reading the driver info */

        /* Get current EOA... */
        eoa = H5FD_get_eoa(udata->f->shared->lf, H5FD_MEM_SUPER);
        if (!H5_addr_defined(eoa))
            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "driver get_eoa request failed");

        /* ... if it is too small, extend it. */
        min_eoa = udata->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE + drvrinfo->len;

        /* If it grew, set it */
        if (H5_addr_gt(min_eoa, eoa))
            if (H5FD_set_eoa(udata->f->shared->lf, H5FD_MEM_SUPER, min_eoa) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "set end of space allocation request failed");
    }

    /* Update the image buffer pointer */
    *image_ref = image;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__drvrinfo_prefix_decode() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_superblock_get_initial_load_size
 *
 * Purpose:     Compute the size of the data structure on disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_superblock_get_initial_load_size(void H5_ATTR_UNUSED *_udata, size_t *image_len)
{
    FUNC_ENTER_PACKAGE_NOERR

    assert(image_len);

    /* Set the initial image length size */
    *image_len = H5F_SUPERBLOCK_FIXED_SIZE + /* Fixed size of superblock */
                 H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5F__cache_superblock_get_initial_load_size() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_superblock_get_final_load_size
 *
 * Purpose:     Compute the final size of the data structure on disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_superblock_get_final_load_size(const void *_image, size_t image_len, void *_udata,
                                          size_t *actual_len)
{
    const uint8_t             *image = _image;                              /* Pointer into raw data buffer */
    H5F_superblock_cache_ud_t *udata = (H5F_superblock_cache_ud_t *)_udata; /* User data */
    H5F_super_t                sblock;                                      /* Temporary file superblock */
    htri_t                     ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(image);
    assert(udata);
    assert(actual_len);
    assert(*actual_len == image_len);
    assert(image_len >= H5F_SUPERBLOCK_FIXED_SIZE + 6);

    /* Deserialize the file superblock's prefix */
    if (H5F__superblock_prefix_decode(&sblock, &image, image_len, udata, true) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, FAIL, "can't decode file superblock prefix");

    /* Save the version to be used in verify_chksum callback */
    udata->super_vers = sblock.super_vers;

    /* Set the final size for the cache image */
    *actual_len = H5F_SUPERBLOCK_FIXED_SIZE + (size_t)H5F_SUPERBLOCK_VARLEN_SIZE(
                                                  sblock.super_vers, sblock.sizeof_addr, sblock.sizeof_size);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__cache_superblock_get_final_load_size() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_superblock_verify_chksum
 *
 * Purpose:     Verify the computed checksum of the data structure is the
 *              same as the stored chksum.
 *
 * Return:      Success:    true/false
 *              Failure:    Negative
 *-------------------------------------------------------------------------
 */
static htri_t
H5F__cache_superblock_verify_chksum(const void *_image, size_t len, void *_udata)
{
    const uint8_t             *image = _image;                              /* Pointer into raw data buffer */
    H5F_superblock_cache_ud_t *udata = (H5F_superblock_cache_ud_t *)_udata; /* User data */
    uint32_t                   stored_chksum;   /* Stored metadata checksum value */
    uint32_t                   computed_chksum; /* Computed metadata checksum value */
    htri_t                     ret_value = true;

    FUNC_ENTER_PACKAGE_NOERR

    assert(image);
    assert(udata);

    /* No checksum for version 0 & 1 */
    if (udata->super_vers >= HDF5_SUPERBLOCK_VERSION_2) {

        /* 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 H5F__cache_superblock_verify_chksum() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_superblock_deserialize
 *
 * Purpose:     Load an object from the disk
 *
 * Return:      Success:    Pointer to new object
 *              Failure:    NULL
 *-------------------------------------------------------------------------
 */
static void *
H5F__cache_superblock_deserialize(const void *_image, size_t len, void *_udata, bool H5_ATTR_UNUSED *dirty)
{
    H5F_super_t               *sblock    = NULL;                                /* File's superblock */
    H5F_superblock_cache_ud_t *udata     = (H5F_superblock_cache_ud_t *)_udata; /* User data */
    const uint8_t             *image     = _image;          /* Pointer into raw data buffer */
    const uint8_t             *end       = image + len - 1; /* Pointer to end of buffer */
    H5F_super_t               *ret_value = NULL;

    FUNC_ENTER_PACKAGE

    assert(image);
    assert(udata);
    assert(udata->f);
    assert(len >= H5F_SUPERBLOCK_FIXED_SIZE + 6);

    /* Allocate space for the superblock */
    if (NULL == (sblock = H5FL_CALLOC(H5F_super_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");

    /* Deserialize the file superblock's prefix */
    if (H5F__superblock_prefix_decode(sblock, &image, len, udata, false) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "can't decode file superblock prefix");

    /* Check for older version of superblock format */
    if (sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
        uint32_t status_flags;  /* File status flags	   */
        unsigned sym_leaf_k;    /* Symbol table leaf node's 'K' value */
        unsigned snode_btree_k; /* B-tree symbol table internal node 'K' value */
        unsigned chunk_btree_k; /* B-tree chunk internal node 'K' value */

        /* Freespace version (hard-wired) */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        if (HDF5_FREESPACE_VERSION != *image++)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad free space version number");

        /* Root group version number (hard-wired) */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        if (HDF5_OBJECTDIR_VERSION != *image++)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad object directory version number");

        /* Skip over reserved byte */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        image++;

        /* Shared header version number (hard-wired) */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        if (HDF5_SHAREDHEADER_VERSION != *image++)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad shared-header format version number");

        /* Skip over size of file addresses (already decoded) */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        image++;
        udata->f->shared->sizeof_addr = sblock->sizeof_addr; /* Keep a local copy also */

        /* Skip over size of file sizes (already decoded) */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        image++;
        udata->f->shared->sizeof_size = sblock->sizeof_size; /* Keep a local copy also */

        /* Skip over reserved byte */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        image++;

        /* Various B-tree sizes */
        if (H5_IS_BUFFER_OVERFLOW(image, 2, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        UINT16DECODE(image, sym_leaf_k);
        if (sym_leaf_k == 0)
            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad symbol table leaf node 1/2 rank");
        udata->sym_leaf_k = sym_leaf_k; /* Keep a local copy also */

        /* Need 'get' call to set other array values */
        if (H5_IS_BUFFER_OVERFLOW(image, 2, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        UINT16DECODE(image, snode_btree_k);
        if (snode_btree_k == 0)
            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad 1/2 rank for btree internal nodes");
        udata->btree_k[H5B_SNODE_ID] = snode_btree_k;

        /* Delay setting the value in the property list until we've checked
         * for the indexed storage B-tree internal 'K' value later.
         */

        /* File status flags (not really used yet) */
        if (H5_IS_BUFFER_OVERFLOW(image, 4, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        UINT32DECODE(image, status_flags);
        if (status_flags > 255)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad superblock status flags");
        sblock->status_flags = (uint8_t)status_flags;
        if (sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock");

        /* If the superblock version # is greater than 0, read in the indexed
         * storage B-tree internal 'K' value
         */
        if (sblock->super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
            if (H5_IS_BUFFER_OVERFLOW(image, 2, end))
                HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
            UINT16DECODE(image, chunk_btree_k);

            /* Reserved bytes are present only in version 1 */
            if (sblock->super_vers == HDF5_SUPERBLOCK_VERSION_1) {
                /* Reserved */
                if (H5_IS_BUFFER_OVERFLOW(image, 2, end))
                    HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
                image += 2;
            }
        }
        else
            chunk_btree_k = HDF5_BTREE_CHUNK_IK_DEF;
        udata->btree_k[H5B_CHUNK_ID] = chunk_btree_k;

        /* Remainder of "variable-sized" portion of superblock */
        if (H5_IS_BUFFER_OVERFLOW(image, H5F_sizeof_addr(udata->f) * 4, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->base_addr /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->ext_addr /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &udata->stored_eof /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->driver_addr /*out*/);

        /* Allocate space for the root group symbol table entry */
        if (sblock->root_ent)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "root entry should not exist yet");
        if (NULL == (sblock->root_ent = (H5G_entry_t *)H5MM_calloc(sizeof(H5G_entry_t))))
            HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL,
                        "can't allocate space for root group symbol table entry");

        /* Decode the root group symbol table entry */
        if (H5G_ent_decode(udata->f, (const uint8_t **)&image, sblock->root_ent, end) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "can't decode root group symbol table entry");

        /* Set the root group address to the correct value */
        sblock->root_addr = sblock->root_ent->header;

        /* This step is for h5repart tool only. If user wants to change file driver
         *  from family to sec2 while using h5repart, set the driver address to
         *  undefined to let the library ignore the family driver information saved
         *  in the superblock.
         */
        if (udata->ignore_drvrinfo && H5_addr_defined(sblock->driver_addr)) {
            /* Eliminate the driver info */
            sblock->driver_addr     = HADDR_UNDEF;
            udata->drvrinfo_removed = true;
        }

        /* NOTE: Driver info block is decoded separately, later */
    }
    else {
        uint32_t read_chksum; /* Checksum read from file  */

        /* Skip over size of file addresses (already decoded) */
        image++;
        udata->f->shared->sizeof_addr = sblock->sizeof_addr; /* Keep a local copy also */
        /* Skip over size of file sizes (already decoded) */
        image++;
        udata->f->shared->sizeof_size = sblock->sizeof_size; /* Keep a local copy also */

        /* Check whether the image pointer is out of bounds */
        if (H5_IS_BUFFER_OVERFLOW(image, 1, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");

        /* File status flags (not really used yet) */
        sblock->status_flags = *image++;
        if (sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock");

        /* Check whether the image pointer will be out of bounds */
        if (H5_IS_BUFFER_OVERFLOW(image, H5F_SIZEOF_ADDR(udata->f) * 4, end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");

        /* Base, superblock extension, end of file & root group object header addresses */
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->base_addr /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->ext_addr /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &udata->stored_eof /*out*/);
        H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->root_addr /*out*/);

        /* checksum verification already done in verify_chksum cb */

        /* Check whether the image pointer will be out of bounds */
        if (H5_IS_BUFFER_OVERFLOW(image, sizeof(uint32_t), end))
            HGOTO_ERROR(H5E_FILE, H5E_OVERFLOW, NULL, "image pointer is out of bounds");

        /* Decode checksum */
        UINT32DECODE(image, read_chksum);

        /* The Driver Information Block may not appear with the version
         * 2 super block.  Thus we set the driver_addr field of the in
         * core representation of the super block HADDR_UNDEF to prevent
         * any attempt to load the Driver Information Block.
         */
        sblock->driver_addr = HADDR_UNDEF;
    }

    /* Size check */
    if ((size_t)(image - (const uint8_t *)_image) > len)
        HDONE_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad decoded superblock size");

    ret_value = sblock;

done:
    /* Release the [possibly partially initialized] superblock on error */
    if (!ret_value && sblock)
        if (H5F__super_free(sblock) < 0)
            HDONE_ERROR(H5E_FILE, H5E_CANTFREE, NULL, "unable to destroy superblock data");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__cache_superblock_deserialize() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_superblock_image_len
 *
 * Purpose:     Compute the size of the data structure on disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_superblock_image_len(const void *_thing, size_t *image_len)
{
    const H5F_super_t *sblock = (const H5F_super_t *)_thing; /* Pointer to the object */

    FUNC_ENTER_PACKAGE_NOERR

    assert(sblock);
    assert(sblock->cache_info.type == H5AC_SUPERBLOCK);
    assert(image_len);

    /* Set the image length size */
    *image_len = (size_t)H5F_SUPERBLOCK_SIZE(sblock);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5F__cache_superblock_image_len() */

/*-------------------------------------------------------------------------
 * Function:	H5F__cache_superblock_serialize
 *
 * Purpose:     Flush a dirty object to disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_superblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len, void *_thing)
{
    H5F_super_t *sblock = (H5F_super_t *)_thing; /* Pointer to the object */
    uint8_t     *image  = _image;                /* Pointer into raw data buffer */
    haddr_t      rel_eof;                        /* Relative EOF for file */
    herr_t       ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(f);
    assert(image);
    assert(sblock);

    /* Assert that the superblock is marked as being flushed last (and
       collectively in parallel) */
    /* (We'll rely on the cache to make sure it actually *is* flushed
       last (and collectively in parallel), but this check doesn't hurt) */
    assert(sblock->cache_info.flush_me_last);

    /* Encode the common portion of the file superblock for all versions */
    H5MM_memcpy(image, H5F_SIGNATURE, (size_t)H5F_SIGNATURE_LEN);
    image += H5F_SIGNATURE_LEN;
    *image++ = (uint8_t)sblock->super_vers;

    /* Check for older version of superblock format */
    if (sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
        *image++ = (uint8_t)HDF5_FREESPACE_VERSION; /* (hard-wired) */
        *image++ = (uint8_t)HDF5_OBJECTDIR_VERSION; /* (hard-wired) */
        *image++ = 0;                               /* reserved*/

        *image++ = (uint8_t)HDF5_SHAREDHEADER_VERSION; /* (hard-wired) */
        *image++ = sblock->sizeof_addr;
        *image++ = sblock->sizeof_size;
        *image++ = 0; /* reserved */

        UINT16ENCODE(image, sblock->sym_leaf_k);
        UINT16ENCODE(image, sblock->btree_k[H5B_SNODE_ID]);
        UINT32ENCODE(image, (uint32_t)sblock->status_flags);

        /*
         * Versions of the superblock >0 have the indexed storage B-tree
         * internal 'K' value stored
         */
        if (sblock->super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
            UINT16ENCODE(image, sblock->btree_k[H5B_CHUNK_ID]);
            *image++ = 0; /*reserved */
            *image++ = 0; /*reserved */
        }                 /* end if */

        /* Encode the base address */
        H5F_addr_encode(f, &image, sblock->base_addr);

        /* Encode the address of global free-space index */
        H5F_addr_encode(f, &image, sblock->ext_addr);

        /* Encode the end-of-file address. Note that at this point in time,
         * the EOF value itself may not be reflective of the file's size, as
         * we will eventually truncate the file to match the EOA value. As
         * such, use the EOA value in its place, knowing that the current EOF
         * value will ultimately match it. */
        if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed");
        H5F_addr_encode(f, &image, (rel_eof + sblock->base_addr));

        /* Encode the driver information block address */
        H5F_addr_encode(f, &image, sblock->driver_addr);

        /* Encode the root group object entry, including the cached stab info */
        if (H5G_ent_encode(f, &image, sblock->root_ent) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTENCODE, FAIL, "can't encode root group symbol table entry");

        /* NOTE: Driver info block is handled separately */

    }                         /* end if */
    else {                    /* sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2 */
        uint32_t   chksum;    /* Checksum temporary variable      */
        H5O_loc_t *root_oloc; /* Pointer to root group's object location */

        /* Size of file addresses & offsets, and status flags */
        *image++ = sblock->sizeof_addr;
        *image++ = sblock->sizeof_size;
        *image++ = sblock->status_flags;

        /* Encode the base address */
        H5F_addr_encode(f, &image, sblock->base_addr);

        /* Encode the address of the superblock extension */
        H5F_addr_encode(f, &image, sblock->ext_addr);

        /* At this point in time, the EOF value itself may
         * not be reflective of the file's size, since we'll eventually
         * truncate it to match the EOA value. As such, use the EOA value
         * in its place, knowing that the current EOF value will
         * ultimately match it. */
        if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed");
        H5F_addr_encode(f, &image, (rel_eof + sblock->base_addr));

        /* Retrieve information for root group */
        if (NULL == (root_oloc = H5G_oloc(f->shared->root_grp)))
            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to retrieve root group information");

        /* Encode address of root group's object header */
        H5F_addr_encode(f, &image, root_oloc->addr);

        /* Compute superblock checksum */
        chksum = H5_checksum_metadata(_image, ((size_t)H5F_SUPERBLOCK_SIZE(sblock) - H5F_SIZEOF_CHKSUM), 0);

        /* Superblock checksum */
        UINT32ENCODE(image, chksum);

        /* Sanity check */
        assert((size_t)(image - (uint8_t *)_image) == (size_t)H5F_SUPERBLOCK_SIZE(sblock));
    }

    /* Sanity check */
    assert((size_t)(image - (uint8_t *)_image) == len);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F__cache_superblock_serialize() */

/*-------------------------------------------------------------------------
 * Function:	H5F__cache_superblock_free_icr
 *
 * Purpose:     Destroy/release an "in core representation" of a data
 *              structure
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_superblock_free_icr(void *_thing)
{
    H5F_super_t *sblock    = (H5F_super_t *)_thing; /* Pointer to the object */
    herr_t       ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(sblock);
    assert(sblock->cache_info.type == H5AC_SUPERBLOCK);

    /* Destroy superblock */
    if (H5F__super_free(sblock) < 0)
        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free superblock");

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F__cache_superblock_free_icr() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_drvrinfo_get_initial_load_size
 *
 * Purpose:     Compute the initial size of the data structure on disk.
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_drvrinfo_get_initial_load_size(void H5_ATTR_UNUSED *_udata, size_t *image_len)
{
    FUNC_ENTER_PACKAGE_NOERR

    assert(image_len);

    /* Set the initial image length size */
    *image_len = H5F_DRVINFOBLOCK_HDR_SIZE; /* Fixed size portion of driver info block */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5F__cache_drvrinfo_get_initial_load_size() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_drvrinfo_get_final_load_size
 *
 * Purpose:     Compute the final size of the data structure on disk.
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_drvrinfo_get_final_load_size(const void *_image, size_t image_len, void *_udata,
                                        size_t *actual_len)
{
    const uint8_t           *image = _image;                            /* Pointer into raw data buffer */
    H5F_drvrinfo_cache_ud_t *udata = (H5F_drvrinfo_cache_ud_t *)_udata; /* User data */
    H5O_drvinfo_t            drvrinfo;                                  /* Driver info */
    herr_t                   ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(image);
    assert(udata);
    assert(actual_len);
    assert(*actual_len == image_len);
    assert(image_len == H5F_DRVINFOBLOCK_HDR_SIZE);

    /* Deserialize the file driver info's prefix */
    if (H5F__drvrinfo_prefix_decode(&drvrinfo, NULL, &image, image_len, udata, true) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, FAIL, "can't decode file driver info prefix");

    /* Set the final size for the cache image */
    *actual_len = H5F_DRVINFOBLOCK_HDR_SIZE + drvrinfo.len;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__cache_drvrinfo_get_final_load_size() */

/*-------------------------------------------------------------------------
 * Function:	H5F__cache_drvrinfo_deserialize
 *
 * Purpose:     Loads an object from the disk
 *
 * Return:      Success:    Pointer to a new driver info struct
 *              Failure:    NULL
 *-------------------------------------------------------------------------
 */
static void *
H5F__cache_drvrinfo_deserialize(const void *_image, size_t len, void *_udata, bool H5_ATTR_UNUSED *dirty)
{
    H5O_drvinfo_t           *drvinfo = NULL;                              /* Driver info */
    H5F_drvrinfo_cache_ud_t *udata   = (H5F_drvrinfo_cache_ud_t *)_udata; /* User data */
    const uint8_t           *image   = _image;                            /* Pointer into raw data buffer */
    char                     drv_name[9];                                 /* Name of driver */
    H5O_drvinfo_t           *ret_value = NULL;

    FUNC_ENTER_PACKAGE

    assert(image);
    assert(len >= H5F_DRVINFOBLOCK_HDR_SIZE);
    assert(udata);
    assert(udata->f);

    /* Allocate space for the driver info */
    if (NULL == (drvinfo = (H5O_drvinfo_t *)H5MM_calloc(sizeof(H5O_drvinfo_t))))
        HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "memory allocation failed for driver info message");

    /* Deserialize the file driver info's prefix */
    if (H5F__drvrinfo_prefix_decode(drvinfo, drv_name, &image, len, udata, false) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "can't decode file driver info prefix");

    /* Sanity check */
    assert(len == (H5F_DRVINFOBLOCK_HDR_SIZE + drvinfo->len));

    /* Validate and decode driver information */
    if (H5FD_sb_load(udata->f->shared->lf, drv_name, image) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "unable to decode driver information");

    /* Sanity check */
    assert((size_t)(image - (const uint8_t *)_image) <= len);

    ret_value = drvinfo;

done:
    /* Release the [possibly partially initialized] driver info message on error */
    if (!ret_value && drvinfo)
        H5MM_xfree(drvinfo);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F__cache_drvrinfo_deserialize() */

/*-------------------------------------------------------------------------
 * Function:    H5F__cache_drvrinfo_image_len
 *
 * Purpose:     Compute the size of the data structure on disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_drvrinfo_image_len(const void *_thing, size_t *image_len)
{
    const H5O_drvinfo_t *drvinfo = (const H5O_drvinfo_t *)_thing; /* Pointer to the object */

    FUNC_ENTER_PACKAGE_NOERR

    assert(drvinfo);
    assert(drvinfo->cache_info.type == H5AC_DRVRINFO);
    assert(image_len);

    /* Set the image length size */
    *image_len = (size_t)(H5F_DRVINFOBLOCK_HDR_SIZE + /* Fixed-size portion of driver info block */
                          drvinfo->len);              /* Variable-size portion of driver info block */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5F__cache_drvrinfo_image_len() */

/*-------------------------------------------------------------------------
 * Function:	H5F__cache_drvrinfo_serialize
 *
 * Purpose:     Flush a dirty object to disk
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_drvrinfo_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_NDEBUG_UNUSED len, void *_thing)
{
    H5O_drvinfo_t *drvinfo = (H5O_drvinfo_t *)_thing; /* Pointer to the object */
    uint8_t       *image   = _image;                  /* Pointer into raw data buffer */
    uint8_t       *dbuf;                              /* Pointer to beginning of driver info */
    herr_t         ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    assert(f);
    assert(image);
    assert(drvinfo);
    assert(drvinfo->cache_info.type == H5AC_DRVRINFO);
    assert(len == (size_t)(H5F_DRVINFOBLOCK_HDR_SIZE + drvinfo->len));

    /* Save pointer to beginning of driver info */
    dbuf = image;

    /* Encode the driver information block */
    *image++ = HDF5_DRIVERINFO_VERSION_0; /* Version */
    *image++ = 0;                         /* reserved */
    *image++ = 0;                         /* reserved */
    *image++ = 0;                         /* reserved */

    /* Driver info size, excluding header */
    UINT32ENCODE(image, drvinfo->len);

    /* Encode driver-specific data */
    if (H5FD_sb_encode(f->shared->lf, (char *)image, dbuf + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information");

    /* Advance buffer pointer past name & variable-sized portion of driver info */
    image += 8 + drvinfo->len;

    /* Sanity check */
    assert((size_t)(image - (uint8_t *)_image) == len);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F__cache_drvrinfo_serialize() */

/*-------------------------------------------------------------------------
 * Function:	H5F__cache_drvrinfo_free_icr
 *
 * Purpose:     Destroy/release an "in core representation" of a data
 *              structure
 *
 * Return:      SUCCEED/FAIL
 *-------------------------------------------------------------------------
 */
static herr_t
H5F__cache_drvrinfo_free_icr(void *_thing)
{
    H5O_drvinfo_t *drvinfo = (H5O_drvinfo_t *)_thing; /* Pointer to the object */

    FUNC_ENTER_PACKAGE_NOERR

    assert(drvinfo);
    assert(drvinfo->cache_info.type == H5AC_DRVRINFO);

    /* Destroy driver info message */
    H5MM_xfree(drvinfo);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* H5F__cache_drvrinfo_free_icr() */