summaryrefslogtreecommitdiffstats
path: root/src/H5Fsuper.c
blob: 2262ccd9987f12cdea4aec5416b7fe652a70f0eb (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
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

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

#define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */

/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC	H5F_init_super_interface


/***********/
/* Headers */
/***********/
#include "H5private.h"		/* Generic Functions                    */
#include "H5ACprivate.h"        /* Metadata cache                       */
#include "H5Eprivate.h"		/* Error handling                       */
#include "H5Fpkg.h"             /* File access                          */
#include "H5FDprivate.h"	/* File drivers                         */
#include "H5Iprivate.h"		/* IDs                                  */
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Pprivate.h"		/* Property lists                       */
#include "H5SMprivate.h"        /* Shared Object Header Messages        */


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


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


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


/********************/
/* Local Prototypes */
/********************/
static herr_t H5F_super_ext_create(H5F_t *f, hid_t dxpl_id, H5O_loc_t *ext_ptr);


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


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

/* Declare a free list to manage the H5F_super_t struct */
H5FL_DEFINE(H5F_super_t);


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



/*--------------------------------------------------------------------------
NAME
   H5F_init_super_interface -- Initialize interface-specific information
USAGE
    herr_t H5F_init_super_interface()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.  (Just calls
    H5F_init() currently).

--------------------------------------------------------------------------*/
static herr_t
H5F_init_super_interface(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(H5F_init())
} /* H5F_init_super_interface() */


/*-------------------------------------------------------------------------
 * Function:    H5F_super_ext_create
 *
 * Purpose:     Create the superblock extension
 *
 * Return:      Success:        non-negative on success
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi; Feb 2009
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_super_ext_create(H5F_t *f, hid_t dxpl_id, H5O_loc_t *ext_ptr)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(f);
    HDassert(f->shared);
    HDassert(f->shared->sblock);
    HDassert(!H5F_addr_defined(f->shared->sblock->ext_addr));
    HDassert(ext_ptr);

    /* Check for older version of superblock format that can't support superblock extensions */
    if(f->shared->sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2)
        HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, FAIL, "superblock extension not permitted with version %u of superblock", f->shared->sblock->super_vers)
    else if(H5F_addr_defined(f->shared->sblock->ext_addr))
        HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, FAIL, "superblock extension already exists?!?!")
    else {
        /* The superblock extension isn't actually a group, but the
         * default group creation list should work fine.
         * If we don't supply a size for the object header, HDF5 will
         * allocate H5O_MIN_SIZE by default.  This is currently
         * big enough to hold the biggest possible extension, but should
         * be tuned if more information is added to the superblock
         * extension.
         */
        H5O_loc_reset(ext_ptr);
        if(H5O_create(f, dxpl_id, 0, (size_t)1, H5P_GROUP_CREATE_DEFAULT, ext_ptr) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTCREATE, FAIL, "unable to create superblock extension")

        /* Record the address of the superblock extension */
        f->shared->sblock->ext_addr = ext_ptr->addr;
    } /* end else */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_ext_create() */


/*-------------------------------------------------------------------------
 * Function:    H5F_super_ext_open
 *
 * Purpose:     Open an existing superblock extension
 *
 * Return:      Success:        non-negative on success
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi; Feb 2009
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_super_ext_open(H5F_t *f, haddr_t ext_addr, H5O_loc_t *ext_ptr)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(f);
    HDassert(H5F_addr_defined(ext_addr));
    HDassert(ext_ptr);

    /* Set up "fake" object location for superblock extension */
    H5O_loc_reset(ext_ptr);
    ext_ptr->file = f;
    ext_ptr->addr = ext_addr;

    /* Open the superblock extension object header */
    if(H5O_open(ext_ptr) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, FAIL, "unable to open superblock extension")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_ext_open() */


/*-------------------------------------------------------------------------
 * Function:   H5F_super_ext_close
 *
 * Purpose:    Close superblock extension
 *
 * Return:     Success:        non-negative on success
 *             Failure:        Negative
 *
 * Programmer:  Vailin Choi; Feb 2009
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_super_ext_close(H5F_t *f, H5O_loc_t *ext_ptr, hid_t dxpl_id,
    hbool_t was_created)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(f);
    HDassert(ext_ptr);

    /* Check if extension was created */
    if(was_created) {
        /* Increment link count on superblock extension's object header */
        if(H5O_link(ext_ptr, 1, dxpl_id) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_LINKCOUNT, FAIL, "unable to increment hard link count")

        /* Decrement refcount on superblock extension's object header in memory */
        if(H5O_dec_rc_by_loc(ext_ptr, dxpl_id) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTDEC, FAIL, "unable to decrement refcount on superblock extension");
    } /* end if */

    /* Twiddle the number of open objects to avoid closing the file. */
    f->nopen_objs++;
    if(H5O_close(ext_ptr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close superblock extension")
    f->nopen_objs--;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_ext_close() */


/*-------------------------------------------------------------------------
 * Function:    H5F__super_read
 *
 * Purpose:     Reads the superblock from the file or from the BUF. If
 *              ADDR is a valid address, then it reads it from the file.
 *              If not, then BUF must be non-NULL for it to read from the
 *              BUF.
 *
 * Return:      Success:        SUCCEED
 *              Failure:        FAIL
 *
 * Programmer:  Bill Wendling
 *              wendling@ncsa.uiuc.edu
 *              Sept 12, 2003
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F__super_read(H5F_t *f, hid_t dxpl_id)
{
    H5P_genplist_t     *dxpl;               /* DXPL object */
    H5F_super_t *       sblock = NULL;      /* Superblock structure */
    H5F_superblock_cache_ud_t udata;        /* User data for cache callbacks */
    H5P_genplist_t     *c_plist;            /* File creation property list  */
    unsigned            sblock_flags = H5AC__NO_FLAGS_SET;       /* flags used in superblock unprotect call      */
    haddr_t             super_addr;         /* Absolute address of superblock */
    haddr_t             eof;                /* End of file address */
    unsigned      	rw_flags;           /* Read/write permissions for file */
    herr_t              ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE_TAG(dxpl_id, H5AC__SUPERBLOCK_TAG, FAIL)

    /* initialize the drvinfo to NULL -- we will overwrite this if there
     * is a driver information block 
     */
    f->shared->drvinfo = NULL;

    /* Get the DXPL plist object for DXPL ID */
    if(NULL == (dxpl = (H5P_genplist_t *)H5I_object(dxpl_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")

    /* Find the superblock */
    if(H5FD_locate_signature(f->shared->lf, dxpl, &super_addr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_NOTHDF5, FAIL, "unable to locate file signature")
    if(HADDR_UNDEF == super_addr)
        HGOTO_ERROR(H5E_FILE, H5E_NOTHDF5, FAIL, "file signature not found")

    /* Check for userblock present */
    if(H5F_addr_gt(super_addr, 0)) {
        /* Set the base address for the file in the VFD now */
        if(H5F__set_base_addr(f, super_addr) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "failed to set base address for file driver")
    } /* end if */

    /* Determine file intent for superblock protect */

    /* Must tell cache at protect time that the super block is to be
     * flushed last (and collectively in the parallel case).
     */
    rw_flags = H5AC__FLUSH_LAST_FLAG;
#ifdef H5_HAVE_PARALLEL
    rw_flags |= H5C__FLUSH_COLLECTIVELY_FLAG;
#endif /* H5_HAVE_PARALLEL */
    if(!(H5F_INTENT(f) & H5F_ACC_RDWR))
        rw_flags |= H5AC__READ_ONLY_FLAG;

    /* Get the shared file creation property list */
    if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
        HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "can't get property list")

    /* Make certain we can read the fixed-size portion of the superblock */
    if(H5F__set_eoa(f, H5FD_MEM_SUPER, 
              H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "set end of space allocation request failed")

    /* Set up the user data for cache callbacks */
    udata.f = f;
    udata.ignore_drvrinfo = H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO);
    udata.sym_leaf_k = 0;
    if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, udata.btree_k) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
    udata.stored_eof = HADDR_UNDEF;
    udata.drvrinfo_removed = FALSE;

    /* Look up the superblock */
    if(NULL == (sblock = (H5F_super_t *)H5AC_protect(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, &udata, rw_flags)))
        HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load superblock")

    /* Pin the superblock in the cache */
    if(H5AC_pin_protected_entry(sblock) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTPIN, FAIL, "unable to pin superblock")

    /* Mark the superblock dirty if it was modified during loading */
    if(((rw_flags & H5AC__READ_ONLY_FLAG) == 0) && udata.ignore_drvrinfo && udata.drvrinfo_removed) {
        HDassert(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2);
        sblock_flags |= H5AC__DIRTIED_FLAG;
    } /* end if */

    /* The superblock must be flushed last (and collectively in parallel) */
    sblock_flags |= H5AC__FLUSH_LAST_FLAG;
#ifdef H5_HAVE_PARALLEL
    sblock_flags |= H5AC__FLUSH_COLLECTIVELY_FLAG;
#endif /* H5_HAVE_PARALLEL */

    /* Check if superblock address is different from base address and adjust
     * base address and "end of address" address if so.
     */
    if(!H5F_addr_eq(super_addr, sblock->base_addr)) {
        /* Check if the superblock moved earlier in the file */
        if(H5F_addr_lt(super_addr, sblock->base_addr))
            udata.stored_eof -= (sblock->base_addr - super_addr);
        else
            /* The superblock moved later in the file */
            udata.stored_eof += (super_addr - sblock->base_addr);

        /* Adjust base address for offsets of the HDF5 data in the file */
        sblock->base_addr = super_addr;

        /* Set the base address for the file in the VFD now */
        if(H5F__set_base_addr(f, sblock->base_addr) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "failed to set base address for file driver")

        /* Indicate that the superblock should be marked dirty */
        if((rw_flags & H5AC__READ_ONLY_FLAG) == 0)
            sblock_flags |= H5AC__DIRTIED_FLAG;
    } /* end if */

    /* Set information in the file's creation property list */
    if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &sblock->super_vers) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set superblock version")
    if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sblock->sizeof_addr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set byte number in an address")
    if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sblock->sizeof_size) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set byte number for object size")

    /* Handle the B-tree 'K' values */
    if(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
        /* Sanity check */
        HDassert(udata.sym_leaf_k != 0);

        /* Set the symbol table internal node 'K' value */
        if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &udata.sym_leaf_k) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
        sblock->sym_leaf_k = udata.sym_leaf_k;

        /* Set the B-tree internal node values, etc */
        if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, udata.btree_k) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
        HDmemcpy(sblock->btree_k, udata.btree_k, sizeof(unsigned) * (size_t)H5B_NUM_BTREE_ID);
    } /* end if */
    else {
        /* Get the (default) B-tree internal node values, etc */
        /* (Note: these may be reset in a superblock extension) */
        if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, sblock->btree_k) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
        if(H5P_get(c_plist, H5F_CRT_SYM_LEAF_NAME, &sblock->sym_leaf_k) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
    } /* end else */

    /*
     * The user-defined data is the area of the file before the base
     * address.
     */
    if(H5P_set(c_plist, H5F_CRT_USER_BLOCK_NAME, &sblock->base_addr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set userblock size")

    /*
     * Make sure that the data is not truncated. One case where this is
     * possible is if the first file of a family of files was opened
     * individually.
     */
    if(HADDR_UNDEF == (eof = H5FD_get_eof(f->shared->lf, H5FD_MEM_DEFAULT)))
        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to determine file size")

    /* (Account for the stored EOA being absolute offset -QAK) */
    if((eof + sblock->base_addr) < udata.stored_eof)
        HGOTO_ERROR(H5E_FILE, H5E_TRUNCATED, FAIL, "truncated file: eof = %llu, sblock->base_addr = %llu, stored_eoa = %llu", (unsigned long long)eof, (unsigned long long)sblock->base_addr, (unsigned long long)udata.stored_eof)

    /*
     * Tell the file driver how much address space has already been
     * allocated so that it knows how to allocate additional memory.
     */

    /* Decode the optional driver information block */
    if(H5F_addr_defined(sblock->driver_addr)) {
        H5O_drvinfo_t *drvinfo;         /* Driver info */
        H5F_drvrinfo_cache_ud_t drvrinfo_udata;  /* User data for metadata callbacks */
        unsigned drvinfo_flags = H5AC__NO_FLAGS_SET;    /* Flags used in driver info block unprotect call */

        /* Sanity check - driver info block should only be defined for
         *      superblock version < 2.
         */
        HDassert(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2);

        /* Set up user data */
        drvrinfo_udata.f           = f;
        drvrinfo_udata.driver_addr = sblock->driver_addr;

        /* extend EOA so we can read at least the fixed sized 
         * portion of the driver info block 
         */
        if(H5FD_set_eoa(f->shared->lf, H5FD_MEM_SUPER, sblock->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE) < 0) /* will extend eoa later if required */ 
            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, \
                        "set end of space allocation request failed")

        /* Look up the driver info block */
        if(NULL == (drvinfo = (H5O_drvinfo_t *)H5AC_protect(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, &drvrinfo_udata, rw_flags)))
            HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load driver info block")

        /* Loading the driver info block is enough to set up the right info */

        /* Check if we need to rewrite the driver info block info */
        if ( ( (rw_flags & H5AC__READ_ONLY_FLAG) == 0 ) &&
             ( H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_DRVRINFO_LOAD) ) ) {

            drvinfo_flags |= H5AC__DIRTIED_FLAG;
        } /* end if */

        /* set the pin entry flag so that the driver information block 
         * cache entry will be pinned in the cache.
         */
        drvinfo_flags |= H5AC__PIN_ENTRY_FLAG;

        /* Release the driver info block */
        if(H5AC_unprotect(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, drvinfo, drvinfo_flags) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTUNPROTECT, FAIL, "unable to release driver info block")

        /* save a pointer to the driver information cache entry */
        f->shared->drvinfo = drvinfo;
    } /* end if */

    /* (Account for the stored EOA being absolute offset -NAF) */
    if(H5F__set_eoa(f, H5FD_MEM_SUPER, udata.stored_eof - sblock->base_addr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set end-of-address marker for file")

    /* Decode the optional superblock extension info */
    if(H5F_addr_defined(sblock->ext_addr)) {
        H5O_loc_t ext_loc;      /* "Object location" for superblock extension */
        H5O_btreek_t btreek;    /* v1 B-tree 'K' value message from superblock extension */
        H5O_drvinfo_t drvinfo;  /* Driver info message from superblock extension */
	size_t u; 		/* Local index variable */
        htri_t status;          /* Status for message existing */

        /* Sanity check - superblock extension should only be defined for
         *      superblock version >= 2.
         */
        HDassert(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2);

        /* Check for superblock extension being located "outside" the stored
         *      'eoa' value, which can occur with the split/multi VFD.
         */
        if(H5F_addr_gt(sblock->ext_addr, udata.stored_eof)) {
            /* Set the 'eoa' for the object header memory type large enough
             *  to give some room for a reasonably sized superblock extension.
             *  (This is _rather_ a kludge -QAK)
             */
            if(H5F__set_eoa(f, H5FD_MEM_OHDR, (haddr_t)(sblock->ext_addr + 1024)) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set end-of-address marker for file")
        } /* end if */

        /* Open the superblock extension */
	if(H5F_super_ext_open(f, sblock->ext_addr, &ext_loc) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")

        /* Check for the extension having a 'driver info' message */
        if((status = H5O_msg_exists(&ext_loc, H5O_DRVINFO_ID, dxpl_id)) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
        if(status) {
            /* Check for ignoring the driver info for this file */
            if(!udata.ignore_drvrinfo) {

                /* Retrieve the 'driver info' structure */
                if(NULL == H5O_msg_read(&ext_loc, H5O_DRVINFO_ID, &drvinfo, dxpl_id))
                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "driver info message not present")

                /* Validate and decode driver information */
                if(H5FD_sb_load(f->shared->lf, drvinfo.name, drvinfo.buf) < 0)
                    HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, FAIL, "unable to decode driver information")

                /* Reset driver info message */
                H5O_msg_reset(H5O_DRVINFO_ID, &drvinfo);
            } /* end else */
        } /* end if */

        /* Read in the shared OH message information if there is any */
        if(H5SM_get_info(&ext_loc, c_plist, dxpl_id) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to read SOHM table information")

        /* Check for the extension having a 'v1 B-tree "K"' message */
        if((status = H5O_msg_exists(&ext_loc, H5O_BTREEK_ID, dxpl_id)) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
        if(status) {
            /* Retrieve the 'v1 B-tree "K"' structure */
            if(NULL == H5O_msg_read(&ext_loc, H5O_BTREEK_ID, &btreek, dxpl_id))
                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "v1 B-tree 'K' info message not present")

            /* Set non-default v1 B-tree 'K' value info from file */
            sblock->btree_k[H5B_CHUNK_ID] = btreek.btree_k[H5B_CHUNK_ID];
            sblock->btree_k[H5B_SNODE_ID] = btreek.btree_k[H5B_SNODE_ID];
            sblock->sym_leaf_k = btreek.sym_leaf_k;

            /* Set non-default v1 B-tree 'K' values in the property list */
            if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btreek.btree_k) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
            if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &btreek.sym_leaf_k) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
        } /* end if */

        /* Check for the extension having a 'free-space manager info' message */
        if((status = H5O_msg_exists(&ext_loc, H5O_FSINFO_ID, dxpl_id)) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
        if(status) {
            H5O_fsinfo_t fsinfo;    /* Free-space manager info message from superblock extension */

            /* Retrieve the 'free-space manager info' structure */
	    if(NULL == H5O_msg_read(&ext_loc, H5O_FSINFO_ID, &fsinfo, dxpl_id))
                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get free-space manager info message")

            /* Check for non-default info */
	    if(f->shared->fs_strategy != fsinfo.strategy) {
		f->shared->fs_strategy = fsinfo.strategy;

		/* Set non-default strategy in the property list */
		if(H5P_set(c_plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &fsinfo.strategy) < 0)
		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set file space strategy")
	    } /* end if */
	    if(f->shared->fs_threshold != fsinfo.threshold) {
		f->shared->fs_threshold = fsinfo.threshold;

		/* Set non-default threshold in the property list */
		if(H5P_set(c_plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &fsinfo.threshold) < 0)
		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set file space strategy")
	    } /* end if */

	    /* Set free-space manager addresses */
	    f->shared->fs_addr[0] = HADDR_UNDEF;
	    for(u = 1; u < NELMTS(f->shared->fs_addr); u++)
		f->shared->fs_addr[u] = fsinfo.fs_addr[u-1];
        } /* end if */

        /* Close superblock extension */
        if(H5F_super_ext_close(f, &ext_loc, dxpl_id, FALSE) < 0)
	    HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close file's superblock extension")
    } /* end if */

    /* Update the driver info if VFD indicated to do so */
    /* (NOTE: only for later versions of superblock, earlier versions are handled
     *          earlier in this routine.
     */
    if(((rw_flags & H5AC__READ_ONLY_FLAG) == 0) &&
            sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2 &&
            H5F_addr_defined(sblock->ext_addr)) {
        /* Check for modifying the driver info when opening the file */
        if(H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_DRVRINFO_LOAD)) {
            size_t          driver_size;    /* Size of driver info block (bytes) */

            /* Check for driver info message */
            H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
            if(driver_size > 0) {
                H5O_drvinfo_t drvinfo;      /* Driver info */
                uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */

                /* Sanity check */
                HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);

                /* Encode driver-specific data */
                if(H5FD_sb_encode(f->shared->lf, drvinfo.name, dbuf) < 0)
                    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")

                /* Set the driver info information for the superblock extension */
                drvinfo.len = driver_size;
                drvinfo.buf = dbuf;

                /* Write driver info information to the superblock extension */

#if 1 /* bug fix test code -- tidy this up if all goes well */ /* JRM */
		/* KLUGE ALERT!!
		 *
		 * H5F_super_ext_write_msg() expects f->shared->sblock to 
		 * be set -- verify that it is NULL, and then set it.
		 * Set it back to NULL when we are done.
		 */
		HDassert(f->shared->sblock == NULL);
		f->shared->sblock = sblock;
#endif /* JRM */

                if(H5F_super_ext_write_msg(f, dxpl_id, &drvinfo, H5O_DRVINFO_ID, FALSE) < 0)
                    HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")

#if 1 /* bug fix test code -- tidy this up if all goes well */ /* JRM */
		f->shared->sblock = NULL;
#endif /* JRM */

            } /* end if */
        } /* end if */
        /* Check for eliminating the driver info block */
        else if(H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
            /* Remove the driver info message from the superblock extension */
            if(H5F_super_ext_remove_msg(f, dxpl_id, H5O_DRVINFO_ID) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "error in removing message from superblock extension")

            /* Check if the superblock extension was removed */
            if(!H5F_addr_defined(sblock->ext_addr))
                sblock_flags |= H5AC__DIRTIED_FLAG;
        } /* end if */
    } /* end if */

    /* Set the pointer to the pinned superblock */
    f->shared->sblock = sblock;

done:
    /* Release the superblock */
    if(sblock && H5AC_unprotect(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, sblock, sblock_flags) < 0)
        HDONE_ERROR(H5E_FILE, H5E_CANTUNPROTECT, FAIL, "unable to close superblock")

    /* If we have failed, make sure no entries are left in the 
     * metadata cache, so that it can be shut down and discarded.
     */
    if(ret_value < 0) { 
        /* Unpin and discard drvinfo cache entry */
        if(f->shared->drvinfo) {
            if(H5AC_unpin_entry(f->shared->drvinfo) < 0)
                HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin driver info")

            /* Evict the driver info block from the cache */
            if(H5AC_expunge_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, H5AC__NO_FLAGS_SET) < 0)
                HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge driver info block")
        } /* end if */

        /* Unpin & discard superblock */
        if(sblock) {
            /* Unpin superblock in cache */
            if(H5AC_unpin_entry(sblock) < 0)
                HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin superblock")

            /* Evict the superblock from the cache */
            if(H5AC_expunge_entry(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, H5AC__NO_FLAGS_SET) < 0)
                HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge superblock")
        } /* end if */
    } /* end if */

    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
} /* end H5F__super_read() */


/*-------------------------------------------------------------------------
 * Function:    H5F__super_init
 *
 * Purpose:     Allocates the superblock for the file and initializes
 *              information about the superblock in memory.  Writes extension
 *              messages if any are needed.
 *
 * Return:      Success:        SUCCEED
 *              Failure:        FAIL
 *
 * Programmer:  Quincey Koziol
 *              koziol@ncsa.uiuc.edu
 *              Sept 15, 2003
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F__super_init(H5F_t *f, hid_t dxpl_id)
{
    H5F_super_t    *sblock = NULL;      /* Superblock cache structure                 */
    hbool_t         sblock_in_cache = FALSE;    /* Whether the superblock has been inserted into the metadata cache */
    H5O_drvinfo_t  *drvinfo = NULL;     /* Driver info */
    hbool_t         drvinfo_in_cache = FALSE;   /* Whether the driver info block has been inserted into the metadata cache */
    H5P_genplist_t *plist;              /* File creation property list                */
    hsize_t         userblock_size;     /* Size of userblock, in bytes                */
    hsize_t         superblock_size;    /* Size of superblock, in bytes               */
    size_t          driver_size;        /* Size of driver info block (bytes)          */
    unsigned super_vers = HDF5_SUPERBLOCK_VERSION_DEF; /* Superblock version for file */
    H5O_loc_t       ext_loc;            /* Superblock extension object location */
    hbool_t         need_ext;           /* Whether the superblock extension is needed */
    hbool_t         ext_created = FALSE; /* Whether the extension has been created */
    herr_t          ret_value = SUCCEED; /* Return Value                              */

    FUNC_ENTER_PACKAGE_TAG(dxpl_id, H5AC__SUPERBLOCK_TAG, FAIL)

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

    /* Initialize various address information */
    sblock->base_addr = HADDR_UNDEF;
    sblock->ext_addr = HADDR_UNDEF;
    sblock->driver_addr = HADDR_UNDEF;
    sblock->root_addr = HADDR_UNDEF;

    /* Get the shared file creation property list */
    if(NULL == (plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")

    /* Initialize sym_leaf_k */
    if(H5P_get(plist, H5F_CRT_SYM_LEAF_NAME, &sblock->sym_leaf_k) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get byte number for object size")

    /* Initialize btree_k */
    if(H5P_get(plist, H5F_CRT_BTREE_RANK_NAME, &sblock->btree_k[0]) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")

    /* Bump superblock version if we are to use the latest version of the format */
    if(f->shared->latest_format)
        super_vers = HDF5_SUPERBLOCK_VERSION_LATEST;
    /* Bump superblock version to create superblock extension for SOHM info */
    else if(f->shared->sohm_nindexes > 0)
        super_vers = HDF5_SUPERBLOCK_VERSION_2;
    /* Bump superblock version to create superblock extension for
     * non-default file space strategy or non-default free-space threshold
     */
    else if(f->shared->fs_strategy != H5F_FILE_SPACE_STRATEGY_DEF ||
            f->shared->fs_threshold != H5F_FREE_SPACE_THRESHOLD_DEF)
        super_vers = HDF5_SUPERBLOCK_VERSION_2;
    /* Check for non-default indexed storage B-tree internal 'K' value
     * and set the version # of the superblock to 1 if it is a non-default
     * value.
     */
    else if(sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF)
        super_vers = HDF5_SUPERBLOCK_VERSION_1;

    /* If a newer superblock version is required, set it here */
    if(super_vers != HDF5_SUPERBLOCK_VERSION_DEF) {
        H5P_genplist_t *c_plist;              /* Property list */

        if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not property list")
        if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set superblock version")
    } /* end if */

    /*
     * The superblock starts immediately after the user-defined
     * header, which we have already insured is a proper size. The
     * base address is set to the same thing as the superblock for
     * now.
     */
    if(H5P_get(plist, H5F_CRT_USER_BLOCK_NAME, &userblock_size) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get userblock size")

    /* Sanity check the userblock size vs. the file's allocation alignment */
    if(userblock_size > 0) {
        if(userblock_size < f->shared->alignment)
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "userblock size must be > file object alignment")
        if(0 != (userblock_size % f->shared->alignment))
            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "userblock size must be an integral multiple of file object alignment")
    } /* end if */

    sblock->base_addr = userblock_size;
    sblock->status_flags = 0;

    /* Reserve space for the userblock */
    if(H5F__set_eoa(f, H5FD_MEM_SUPER, userblock_size) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to set EOA value for userblock")

    /* Set the base address for the file in the VFD now, after allocating
     *  space for userblock.
     */
    if(H5F__set_base_addr(f, sblock->base_addr) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set base address for file driver")

    /* Save a local copy of the superblock version number, size of addresses & offsets */
    sblock->super_vers = super_vers;
    sblock->sizeof_addr = f->shared->sizeof_addr;
    sblock->sizeof_size = f->shared->sizeof_size;

    /* Compute the size of the superblock */
    superblock_size = (hsize_t)H5F_SUPERBLOCK_SIZE(sblock);

    /* Compute the size of the driver information block */
    H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
    if(driver_size > 0) {
        driver_size += H5F_DRVINFOBLOCK_HDR_SIZE;

        /*
         * The file driver information block begins immediately after the
         * superblock. (relative to base address in file)
         */
        sblock->driver_addr = superblock_size;
    } /* end if */

    /*
     * Allocate space for the superblock & driver info block.
     * We do it with one allocation request because the superblock needs to be
     * at the beginning of the file and only the first allocation request is
     * required to return memory at format address zero.
     */
    if(super_vers < HDF5_SUPERBLOCK_VERSION_2)
        superblock_size += driver_size;

    /* Reserve space in the file for the superblock, instead of allocating it */
    if(H5F__set_eoa(f, H5FD_MEM_SUPER, superblock_size) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to set EOA value for superblock")

    /* Insert superblock into cache, pinned */
    if(H5AC_insert_entry(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, sblock, H5AC__PIN_ENTRY_FLAG | H5AC__FLUSH_LAST_FLAG | H5AC__FLUSH_COLLECTIVELY_FLAG) < 0)
        HGOTO_ERROR(H5E_CACHE, H5E_CANTINS, FAIL, "can't add superblock to cache")
    sblock_in_cache = TRUE;

    /* Keep a copy of the superblock info */
    f->shared->sblock = sblock;

    /* set the drvinfo filed to NULL -- will overwrite this later if needed */
    f->shared->drvinfo = NULL;

    /*
     * Determine if we will need a superblock extension
     */

    /* Files with SOHM indices always need the superblock extension */
    if(f->shared->sohm_nindexes > 0) {
        HDassert(super_vers >= HDF5_SUPERBLOCK_VERSION_2);
        need_ext = TRUE;
    } /* end if */
    /* Files with non-default free space settings always need the superblock extension */
    else if(f->shared->fs_strategy != H5F_FILE_SPACE_STRATEGY_DEF ||
            f->shared->fs_threshold != H5F_FREE_SPACE_THRESHOLD_DEF) {
        HDassert(super_vers >= HDF5_SUPERBLOCK_VERSION_2);
        need_ext = TRUE;
    } /* end if */
    /* If we're going to use a version of the superblock format which allows
     *  for the superblock extension, check for non-default values to store
     *  in it.
     */
    else if(super_vers >= HDF5_SUPERBLOCK_VERSION_2) {
        /* Check for non-default v1 B-tree 'K' values to store */
        if(sblock->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
                sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
                sblock->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF)
            need_ext = TRUE;
        /* Check for driver info to store */
        else if(driver_size > 0)
            need_ext = TRUE;
        else
            need_ext = FALSE;
    } /* end if */
    else
        need_ext = FALSE;

    /* Create the superblock extension for "extra" superblock data, if necessary. */
    if(need_ext) {
        /* The superblock extension isn't actually a group, but the
         * default group creation list should work fine.
         * If we don't supply a size for the object header, HDF5 will
         * allocate H5O_MIN_SIZE by default.  This is currently
         * big enough to hold the biggest possible extension, but should
         * be tuned if more information is added to the superblock
         * extension.
         */
	if(H5F_super_ext_create(f, dxpl_id, &ext_loc) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, FAIL, "unable to create superblock extension")
        ext_created = TRUE;

        /* Create the Shared Object Header Message table and register it with
         *      the metadata cache, if this file supports shared messages.
         */
        if(f->shared->sohm_nindexes > 0) {
            /* Initialize the shared message code & write the SOHM message to the extension */
            if(H5SM_init(f, plist, &ext_loc, dxpl_id) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to create SOHM table")
        } /* end if */

        /* Check for non-default v1 B-tree 'K' values to store */
        if(sblock->btree_k[H5B_SNODE_ID] != HDF5_BTREE_SNODE_IK_DEF ||
                sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF ||
                sblock->sym_leaf_k != H5F_CRT_SYM_LEAF_DEF) {
            H5O_btreek_t btreek;        /* v1 B-tree 'K' value message for superblock extension */

            /* Write v1 B-tree 'K' value information to the superblock extension */
            btreek.btree_k[H5B_CHUNK_ID] = sblock->btree_k[H5B_CHUNK_ID];
            btreek.btree_k[H5B_SNODE_ID] = sblock->btree_k[H5B_SNODE_ID];
            btreek.sym_leaf_k = sblock->sym_leaf_k;
            if(H5O_msg_create(&ext_loc, H5O_BTREEK_ID, H5O_MSG_FLAG_CONSTANT | H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &btreek, dxpl_id) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update v1 B-tree 'K' value header message")
        } /* end if */

        /* Check for driver info to store */
        if(driver_size > 0) {
            H5O_drvinfo_t info;      /* Driver info */
            uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */

            /* Sanity check */
            HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);

            /* Encode driver-specific data */
            if(H5FD_sb_encode(f->shared->lf, info.name, dbuf) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")

            /* Write driver info information to the superblock extension */
            info.len = driver_size;
            info.buf = dbuf;
            if(H5O_msg_create(&ext_loc, H5O_DRVINFO_ID, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &info, dxpl_id) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update driver info header message")
        } /* end if */

        /* Check for non-default free space settings */
	if(f->shared->fs_strategy != H5F_FILE_SPACE_STRATEGY_DEF ||
                f->shared->fs_threshold != H5F_FREE_SPACE_THRESHOLD_DEF) {
	    H5FD_mem_t   type;         	/* Memory type for iteration */
            H5O_fsinfo_t fsinfo;	/* Free space manager info message */

	    /* Write free-space manager info message to superblock extension object header if needed */
	    fsinfo.strategy = f->shared->fs_strategy;
	    fsinfo.threshold = f->shared->fs_threshold;
	    for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
                fsinfo.fs_addr[type-1] = HADDR_UNDEF;

            if(H5O_msg_create(&ext_loc, H5O_FSINFO_ID, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &fsinfo, dxpl_id) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update free-space info header message")
	} /* end if */
    } /* end if */
    else {
        /* Check for creating an "old-style" driver info block */
        if(driver_size > 0) {
            /* Sanity check */
            HDassert(H5F_addr_defined(sblock->driver_addr));

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

            /* Set up driver info message */
            /* (NOTE: All the actual information (name & driver information) is
             *          actually based on the VFD info in the file handle and
             *          will be encoded by the VFD's 'encode' callback, so it
             *          doesn't need to be set here. -QAK, 7/20/2013
             */
            H5_CHECKED_ASSIGN(drvinfo->len, size_t, H5FD_sb_size(f->shared->lf), hsize_t);

            /* Insert driver info block into cache */
            if(H5AC_insert_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, drvinfo, H5AC__PIN_ENTRY_FLAG | H5AC__FLUSH_LAST_FLAG | H5AC__FLUSH_COLLECTIVELY_FLAG) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTINS, FAIL, "can't add driver info block to cache")
            drvinfo_in_cache = TRUE;
            f->shared->drvinfo = drvinfo;
        } /* end if */
        else
            HDassert(!H5F_addr_defined(sblock->driver_addr));
    } /* end if */

done:
    /* Close superblock extension, if it was created */
    if(ext_created && H5F_super_ext_close(f, &ext_loc, dxpl_id, ext_created) < 0)
        HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "unable to close file's superblock extension")

    /* Cleanup on failure */
    if(ret_value < 0) {
        /* Check if the driver info block has been allocated yet */
        if(drvinfo) {
            /* Check if we've cached it already */
            if(drvinfo_in_cache) {
                /* Unpin drvinfo in cache */
                if(H5AC_unpin_entry(drvinfo) < 0)
                    HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin driver info")

                /* Evict the driver info block from the cache */
                if(H5AC_expunge_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, H5AC__NO_FLAGS_SET) < 0)
                    HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge driver info block")
            } /* end if */
            else
                /* Free driver info block */
                H5MM_xfree(drvinfo);
        } /* end if */

        /* Check if the superblock has been allocated yet */
        if(sblock) {
            /* Check if we've cached it already */
            if(sblock_in_cache) {
                /* Unpin superblock in cache */
                if(H5AC_unpin_entry(sblock) < 0)
                    HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin superblock")

                /* Evict the superblock from the cache */
                if(H5AC_expunge_entry(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, H5AC__NO_FLAGS_SET) < 0)
                    HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge superblock")
            } /* end if */
            else
                /* Free superblock */
                if(H5F__super_free(sblock) < 0)
                    HDONE_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "unable to destroy superblock")

            /* Reset variables in file structure */
            f->shared->sblock = NULL;
        } /* end if */
    } /* end if */

    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
} /* end H5F__super_init() */


/*-------------------------------------------------------------------------
 * Function:    H5F_super_dirty
 *
 * Purpose:     Mark the file's superblock dirty
 *
 * Return:      Success:        non-negative on success
 *              Failure:        Negative
 *
 * Programmer:  Quincey Koziol
 *              August 14, 2009
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_super_dirty(H5F_t *f)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Sanity check */
    HDassert(f);
    HDassert(f->shared);
    HDassert(f->shared->sblock);

    /* Mark superblock dirty in cache, so change to EOA will get encoded */
    if(H5AC_mark_entry_dirty(f->shared->sblock) < 0)
        HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")

    /* if the driver information block exists, mark it dirty as well 
     * so that the change in eoa will be reflected there as well if 
     * appropriate.
     */
    if ( f->shared->drvinfo )
        if(H5AC_mark_entry_dirty(f->shared->drvinfo) < 0)
            HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark drvinfo as dirty")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_dirty() */


/*-------------------------------------------------------------------------
 * Function:    H5F__super_free
 *
 * Purpose:     Destroyer the file's superblock
 *
 * Return:      Success:        non-negative on success
 *              Failure:        Negative
 *
 * Programmer:  Quincey Koziol
 *              April 1, 2010
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F__super_free(H5F_super_t *sblock)
{
    FUNC_ENTER_PACKAGE_NOERR

    /* Sanity check */
    HDassert(sblock);

    /* Free root group symbol table entry, if any */
    sblock->root_ent = (H5G_entry_t *)H5MM_xfree(sblock->root_ent);

    /* Free superblock */
    sblock = (H5F_super_t *)H5FL_FREE(H5F_super_t, sblock);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* H5F__super_free() */


/*-------------------------------------------------------------------------
 * Function:    H5F__super_size
 *
 * Purpose:     Get storage size of the superblock and superblock extension
 *
 * Return:      Success:        non-negative on success
 *              Failure:        Negative
 *
 * Programmer:  Vailin Choi
 *              July 11, 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F__super_size(H5F_t *f, hid_t dxpl_id, hsize_t *super_size, hsize_t *super_ext_size)
{
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    HDassert(f);
    HDassert(f->shared);
    HDassert(f->shared->sblock);

    /* Set the superblock size */
    if(super_size)
	*super_size = (hsize_t)H5F_SUPERBLOCK_SIZE(f->shared->sblock);

    /* Set the superblock extension size */
    if(super_ext_size) {
        if(H5F_addr_defined(f->shared->sblock->ext_addr)) {
            H5O_loc_t ext_loc;          /* "Object location" for superblock extension */
            H5O_hdr_info_t hdr_info;    /* Object info for superblock extension */

            /* Set up "fake" object location for superblock extension */
            H5O_loc_reset(&ext_loc);
            ext_loc.file = f;
            ext_loc.addr = f->shared->sblock->ext_addr;

            /* Get object header info for superblock extension */
            if(H5O_get_hdr_info(&ext_loc, dxpl_id, &hdr_info) < 0)
                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to retrieve superblock extension info")

            /* Set the superblock extension size */
            *super_ext_size = hdr_info.space.total;
        } /* end if */
        else
            /* Set the superblock extension size to zero */
            *super_ext_size = (hsize_t)0;
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F__super_size() */


/*-------------------------------------------------------------------------
 * Function:    H5F_super_ext_write_msg()
 *
 * Purpose:     Write the message with ID to the superblock extension
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Vailin Choi; Feb 2009
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_super_ext_write_msg(H5F_t *f, hid_t dxpl_id, void *mesg, unsigned id, hbool_t may_create)
{
    hbool_t     ext_created = FALSE;   /* Whether superblock extension was created */
    hbool_t     ext_opened = FALSE;    /* Whether superblock extension was opened */
    H5O_loc_t 	ext_loc; 	/* "Object location" for superblock extension */
    htri_t 	status;       	/* Indicate whether the message exists or not */
    herr_t 	ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Sanity checks */
    HDassert(f);
    HDassert(f->shared);
    HDassert(f->shared->sblock);

    /* Open/create the superblock extension object header */
    if(H5F_addr_defined(f->shared->sblock->ext_addr)) {
	if(H5F_super_ext_open(f, f->shared->sblock->ext_addr, &ext_loc) < 0)
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")
    } /* end if */
    else {
        HDassert(may_create);
	if(H5F_super_ext_create(f, dxpl_id, &ext_loc) < 0)
	    HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, FAIL, "unable to create file's superblock extension")
        ext_created = TRUE;
    } /* end else */
    HDassert(H5F_addr_defined(ext_loc.addr));
    ext_opened = TRUE;

    /* Check if message with ID does not exist in the object header */
    if((status = H5O_msg_exists(&ext_loc, id, dxpl_id)) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to check object header for message or message exists")

    /* Check for creating vs. writing */
    if(may_create) {
	if(status)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "Message should not exist")

	/* Create the message with ID in the superblock extension */
	if(H5O_msg_create(&ext_loc, id, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, mesg, dxpl_id) < 0)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to create the message in object header")
    } /* end if */
    else {
	if(!status)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "Message should exist")

	/* Update the message with ID in the superblock extension */
	if(H5O_msg_write(&ext_loc, id, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, mesg, dxpl_id) < 0)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to write the message in object header")
    } /* end else */

done:
    /* Close the superblock extension, if it was opened */
    if(ext_opened && H5F_super_ext_close(f, &ext_loc, dxpl_id, ext_created) < 0)
        HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "unable to close file's superblock extension")

    /* Mark superblock dirty in cache, if superblock extension was created */
    if(ext_created && H5AC_mark_entry_dirty(f->shared->sblock) < 0)
        HDONE_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_ext_write_msg() */


/*-------------------------------------------------------------------------
 * Function:    H5F_super_ext_remove_msg
 *
 * Purpose:     Remove the message with ID from the superblock extension
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Vailin Choi; Feb 2009
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_super_ext_remove_msg(H5F_t *f, hid_t dxpl_id, unsigned id)
{
    H5O_loc_t 	ext_loc; 	/* "Object location" for superblock extension */
    hbool_t     ext_opened = FALSE;     /* Whether the superblock extension was opened */
    int		null_count = 0;	/* # of null messages */
    htri_t      status;         /* Indicate whether the message exists or not */
    herr_t 	ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Make sure that the superblock extension object header exists */
    HDassert(H5F_addr_defined(f->shared->sblock->ext_addr));

    /* Open superblock extension object header */
    if(H5F_super_ext_open(f, f->shared->sblock->ext_addr, &ext_loc) < 0)
	HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "error in starting file's superblock extension")
    ext_opened = TRUE;

    /* Check if message with ID exists in the object header */
    if((status = H5O_msg_exists(&ext_loc, id, dxpl_id)) < 0)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to check object header for message")
    else if(status) { /* message exists */
	H5O_hdr_info_t 	hdr_info;       /* Object header info for superblock extension */

	/* Remove the message */
	if(H5O_msg_remove(&ext_loc, id, H5O_ALL, TRUE, dxpl_id) < 0)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "unable to delete free-space manager info message")

	/* Get info for the superblock extension's object header */
	if(H5O_get_hdr_info(&ext_loc, dxpl_id, &hdr_info) < 0)
	    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve superblock extension info")

	/* If the object header is an empty base chunk, remove superblock extension */
	if(hdr_info.nchunks == 1) {
	    if((null_count = H5O_msg_count(&ext_loc, H5O_NULL_ID, dxpl_id)) < 0)
		HGOTO_ERROR(H5E_SYM, H5E_CANTCOUNT, FAIL, "unable to count messages")
	    else if((unsigned)null_count == hdr_info.nmesgs) {
		HDassert(H5F_addr_defined(ext_loc.addr));
		if(H5O_delete(f, dxpl_id, ext_loc.addr) < 0)
		    HGOTO_ERROR(H5E_SYM, H5E_CANTCOUNT, FAIL, "unable to count messages")
		f->shared->sblock->ext_addr = HADDR_UNDEF;
	    } /* end if */
	} /* end if */
    } /* end if */

done:
    /* Close superblock extension object header, if opened */
    if(ext_opened && H5F_super_ext_close(f, &ext_loc, dxpl_id, FALSE) < 0)
       HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "unable to close file's superblock extension")

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5F_super_ext_remove_msg() */