summaryrefslogtreecommitdiffstats
path: root/src/H5Dvirtual.c
blob: cbd9e3574e2057012056501c22504fe18ae57742 (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
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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 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.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  Neil Fortner <nfortne2@hdfgroup.org>
 *              Wednesday, January 28, 2015
 *
 * Purpose:
 *      Virtual Dataset (VDS) functions.  Creates a layout type which allows
 *      definition of a virtual dataset, where the actual dataset is stored in
 *      other datasets (called source datasets).  The mappings between the
 *      virtual and source datasets are specified by hyperslab or "all"
 *      dataspace selections.  Point selections are not currently supported.
 *      Overlaps in the mappings in the virtual dataset result in undefined
 *      behaviour.
 *
 *      Mapping selections may be unlimited, in which case the size of the
 *      virtual dataset is determined by the size of the source dataset(s).
 *      Names for the source datasets may also be generated procedurally, in
 *      which case the virtual selection should be unlimited with an unlimited
 *      count and the source selection should be limited with a size equal to
 *      that of the virtual selection with the unlimited count set to 1.
 *
 *      Source datasets are opened lazily (only when needed for I/O or to
 *      determine the size of the virtual dataset), and are currently held open
 *      until the virtual dataset is closed.
 */

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

#include "H5Dmodule.h"          /* This source code file is part of the H5D module */


/***********/
/* Headers */
/***********/
#include "H5private.h"          /* Generic Functions                    */
#include "H5Dpkg.h"             /* Dataset functions                    */
#include "H5Eprivate.h"         /* Error handling                       */
#include "H5Fprivate.h"         /* Files                                */
#include "H5FLprivate.h"        /* Free Lists                           */
#include "H5Gprivate.h"         /* Groups                               */
#include "H5HGprivate.h"        /* Global Heaps                         */
#include "H5Iprivate.h"         /* IDs                                  */
#include "H5MMprivate.h"        /* Memory management                    */
#include "H5Oprivate.h"         /* Object headers                       */
#include "H5Sprivate.h"         /* Dataspaces                           */


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

/* Default size for sub_dset array */
#define H5D_VIRTUAL_DEF_SUB_DSET_SIZE 128


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


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

/* Layout operation callbacks */
static herr_t H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t
    *type_info, hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
    H5D_chunk_map_t *fm);
static herr_t H5D__virtual_write(H5D_io_info_t *io_info,
    const H5D_type_info_t *type_info, hsize_t nelmts, const H5S_t *file_space,
    const H5S_t *mem_space, H5D_chunk_map_t *fm);
static herr_t H5D__virtual_flush(H5D_t *dset, hid_t dxpl_id);

/* Other functions */
static herr_t H5D__virtual_open_source_dset(const H5D_t *vdset,
    H5O_storage_virtual_ent_t *virtual_ent,
    H5O_storage_virtual_srcdset_t *source_dset, hid_t dxpl_id);
static herr_t H5D__virtual_reset_source_dset(
    H5O_storage_virtual_ent_t *virtual_ent,
    H5O_storage_virtual_srcdset_t *source_dset);
static herr_t H5D__virtual_str_append(const char *src, size_t src_len, char **p,
    char **buf, size_t *buf_size);
static herr_t H5D__virtual_copy_parsed_name(
    H5O_storage_virtual_name_seg_t **dst, H5O_storage_virtual_name_seg_t *src);
static herr_t H5D__virtual_build_source_name(char *source_name,
    const H5O_storage_virtual_name_seg_t *parsed_name, size_t static_strlen,
    size_t nsubs, hsize_t blockno, char **built_name);
static herr_t H5D__virtual_init_all(const H5D_t *dset, hid_t dxpl_id);
static herr_t H5D__virtual_pre_io(H5D_io_info_t *io_info,
    H5O_storage_virtual_t *storage, const H5S_t *file_space,
    const H5S_t *mem_space, hsize_t *tot_nelmts);
static herr_t H5D__virtual_post_io(H5O_storage_virtual_t *storage);
static herr_t H5D__virtual_read_one(H5D_io_info_t *io_info,
    const H5D_type_info_t *type_info, const H5S_t *file_space,
    H5O_storage_virtual_srcdset_t *source_dset);
static herr_t H5D__virtual_write_one(H5D_io_info_t *io_info,
    const H5D_type_info_t *type_info, const H5S_t *file_space,
    H5O_storage_virtual_srcdset_t *source_dset);


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

/* Contiguous storage layout I/O ops */
const H5D_layout_ops_t H5D_LOPS_VIRTUAL[1] = {{
    NULL,
    H5D__virtual_init,
    H5D__virtual_is_space_alloc,
    NULL,
    H5D__virtual_read,
    H5D__virtual_write,
#ifdef H5_HAVE_PARALLEL
    NULL,
    NULL,
#endif /* H5_HAVE_PARALLEL */
    NULL,
    NULL,
    H5D__virtual_flush,
    NULL
}};


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

/* Declare a free list to manage the H5O_storage_virtual_name_seg_t struct */
H5FL_DEFINE(H5O_storage_virtual_name_seg_t);



/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_check_mapping_pre
 *
 * Purpose:     Checks that the provided virtual and source selections are
 *              legal for use as a VDS mapping, prior to creating the rest
 *              of the mapping entry.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              August 12, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_check_mapping_pre(const H5S_t *vspace, const H5S_t *src_space,
    H5O_virtual_space_status_t space_status)
{
    H5S_sel_type    select_type; /* Selection type */
    hsize_t         nelmts_vs;  /* Number of elements in virtual selection */
    hsize_t         nelmts_ss;  /* Number of elements in source selection */
    herr_t          ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Check for point selections (currently unsupported) */
    if(H5S_SEL_ERROR == (select_type = H5S_GET_SELECT_TYPE(vspace)))
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get selection type")
    if(select_type == H5S_SEL_POINTS)
        HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "point selections not currently supported with virtual datasets")
    if(H5S_SEL_ERROR == (select_type = H5S_GET_SELECT_TYPE(src_space)))
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get selection type")
    if(select_type == H5S_SEL_POINTS)
        HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "point selections not currently supported with virtual datasets")

    /* Get number of elements in spaces */
    nelmts_vs = (hsize_t)H5S_GET_SELECT_NPOINTS(vspace);
    nelmts_ss = (hsize_t)H5S_GET_SELECT_NPOINTS(src_space);

    /* Check for unlimited vspace */
    if(nelmts_vs == H5S_UNLIMITED) {
        /* Check for unlimited src_space */
        if(nelmts_ss == H5S_UNLIMITED) {
            hsize_t nenu_vs;    /* Number of elements in the non-unlimited dimensions of vspace */
            hsize_t nenu_ss;    /* Number of elements in the non-unlimited dimensions of src_space */

            /* Non-printf unlimited selection.  Make sure both selections have
             * the same number of elements in the non-unlimited dimension.  Note
             * we can always check this even if the space status is invalid
             * because unlimited selections are never dependent on the extent.
             */
            if(H5S_get_select_num_elem_non_unlim(vspace, &nenu_vs) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "can't get number of elements in non-unlimited dimension")
            if(H5S_get_select_num_elem_non_unlim(src_space, &nenu_ss) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "can't get number of elements in non-unlimited dimension")
            if(nenu_vs != nenu_ss)
                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "numbers of elemnts in the non-unlimited dimensions is different for source and virtual spaces")
        } /* end if */
        /* We will handle the printf case after parsing the source names */
    } /* end if */
    else if(space_status != H5O_VIRTUAL_STATUS_INVALID)
        /* Limited selections.  Check number of points is the same. */
        if(nelmts_vs != nelmts_ss)
            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "virtual and source space selections have different numbers of elements")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_check_mapping_pre() */


/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_check_mapping_post
 *
 * Purpose:     Checks that the provided virtual dataset mapping entry is
 *              legal, after the mapping is otherwise complete.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              August 12, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_check_mapping_post(const H5O_storage_virtual_ent_t *ent)
{
    hsize_t         nelmts_vs;  /* Number of elements in virtual selection */
    hsize_t         nelmts_ss;  /* Number of elements in source selection */
    H5S_t           *tmp_space = NULL; /* Temporary dataspace */
    herr_t          ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Get number of elements in spaces */
    nelmts_vs = (hsize_t)H5S_GET_SELECT_NPOINTS(ent->source_dset.virtual_select);
    nelmts_ss = (hsize_t)H5S_GET_SELECT_NPOINTS(ent->source_select);

    /* Check for printf selection */
    if((nelmts_vs == H5S_UNLIMITED) && (nelmts_ss != H5S_UNLIMITED)) {
        /* Make sure there at least one %b substitution in the source file or
         * dataset name */
        if((ent->psfn_nsubs == 0) && (ent->psdn_nsubs == 0))
            HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "unlimited virtual selection, limited source selection, and no printf specifiers in source names")

        /* Make sure virtual space uses hyperslab selection */
        if(H5S_GET_SELECT_TYPE(ent->source_dset.virtual_select) != H5S_SEL_HYPERSLABS)
            HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "virtual selection with printf mapping must be hyperslab")

        /* Check that the number of elements in one block in the virtual
         * selection matches the total number of elements in the source
         * selection, if the source space status is not invalid (virtual space
         * status does not matter here because it is unlimited) */
        if(ent->source_space_status != H5O_VIRTUAL_STATUS_INVALID) {
            /* Get first block in virtual selection */
            if(NULL == (tmp_space = H5S_hyper_get_unlim_block(ent->source_dset.virtual_select, (hsize_t)0)))
                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get first block in virtual selection")

            /* Check number of points */
            nelmts_vs = (hsize_t)H5S_GET_SELECT_NPOINTS(tmp_space);
            if(nelmts_vs != nelmts_ss)
                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "virtual (single block) and source space selections have different numbers of elements")
        } /* end if */
    } /* end if */
    else
        /* Make sure there are no printf substitutions */
        if((ent->psfn_nsubs > 0) || (ent->psdn_nsubs > 0))
            HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "printf specifier(s) in source name(s) without an unlimited virtual selection and limited source selection")

done:
    /* Free temporary space */
    if(tmp_space)
        if(H5S_close(tmp_space) < 0)
            HDONE_ERROR(H5E_PLIST, H5E_CLOSEERROR, FAIL, "can't close dataspace")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_check_mapping_post() */


/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_update_min_dims
 *
 * Purpose:     Updates the virtual layout's "min_dims" field to take into
 *              account the "idx"th entry in the mapping list.  The entry
 *              must be complete, though top level field list_nused (and
 *              of course min_dims) does not need to take it into account.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 10, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_update_min_dims(H5O_layout_t *layout, size_t idx)
{
    H5S_sel_type    sel_type;
    int             rank;
    hsize_t         bounds_start[H5S_MAX_RANK];
    hsize_t         bounds_end[H5S_MAX_RANK];
    int             i;
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    HDassert(layout);
    HDassert(layout->type == H5D_VIRTUAL);
    HDassert(idx < layout->storage.u.virt.list_nalloc);

    /* Get type of selection */
    if(H5S_SEL_ERROR == (sel_type = H5S_GET_SELECT_TYPE(layout->storage.u.virt.list[idx].source_dset.virtual_select)))
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection type")

    /* Do not update min_dims for "all" or "none" selections */
    if((sel_type == H5S_SEL_ALL) || (sel_type == H5S_SEL_NONE))
        HGOTO_DONE(SUCCEED)

    /* Get rank of vspace */
    if((rank = H5S_GET_EXTENT_NDIMS(layout->storage.u.virt.list[idx].source_dset.virtual_select)) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get number of dimensions")

    /* Get selection bounds */
    if(H5S_SELECT_BOUNDS(layout->storage.u.virt.list[idx].source_dset.virtual_select, bounds_start, bounds_end) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")

    /* Update min_dims */
    for(i = 0; i < rank; i++)
        /* Don't check unlimited dimensions in the selection */
        if((i != layout->storage.u.virt.list[idx].unlim_dim_virtual)
                && (bounds_end[i] >= layout->storage.u.virt.min_dims[i]))
            layout->storage.u.virt.min_dims[i] = bounds_end[i] + (hsize_t)1;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_update_min_dims() */


/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_check_min_dims
 *
 * Purpose:     Checks if the dataset's dimensions are at least the
 *              calculated minimum dimensions from the mappings.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              August 13, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_check_min_dims(const H5D_t *dset)
{
    int             rank;
    hsize_t         dims[H5S_MAX_RANK];
    int             i;
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    HDassert(dset);
    HDassert(dset->shared);
    HDassert(dset->shared->layout.type == H5D_VIRTUAL);

    /* Get rank of dataspace */
    if((rank = H5S_GET_EXTENT_NDIMS(dset->shared->space)) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get number of dimensions")

    /* Get VDS dimensions */
    if(H5S_get_simple_extent_dims(dset->shared->space, dims, NULL) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get VDS dimensions")

    /* Verify that dimensions are larger than min_dims */
    for(i = 0; i < rank; i++)
        if(dims[i] < dset->shared->layout.storage.u.virt.min_dims[i])
            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "virtual dataset dimensions not large enough to contain all limited dimensions in all selections")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_check_min_dims() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_copy_layout
 *
 * Purpose:     Deep copies virtual storage layout message in memory.
 *              This function assumes that the top-level struct has
 *              already been copied (so the source struct retains
 *              ownership of the fields passed to this function).
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 10, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_copy_layout(H5O_layout_t *layout)
{
    H5O_storage_virtual_ent_t *orig_list = NULL;
    hid_t           orig_source_fapl;
    hid_t           orig_source_dapl;
    H5P_genplist_t *plist;
    size_t          i;
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    HDassert(layout);
    HDassert(layout->type == H5D_VIRTUAL);

    /* Save original entry list and top-level property lists and reset in layout
     * so the originals aren't closed on error */
    orig_source_fapl = layout->storage.u.virt.source_fapl;
    layout->storage.u.virt.source_fapl = -1;
    orig_source_dapl = layout->storage.u.virt.source_dapl;
    layout->storage.u.virt.source_dapl = -1;
    orig_list = layout->storage.u.virt.list;
    layout->storage.u.virt.list = NULL;

    /* Copy entry list */
    if(layout->storage.u.virt.list_nused > 0) {
        HDassert(orig_list);

        /* Allocate memory for the list */
        if(NULL == (layout->storage.u.virt.list = (H5O_storage_virtual_ent_t *)H5MM_calloc(layout->storage.u.virt.list_nused * sizeof(H5O_storage_virtual_ent_t))))
            HGOTO_ERROR(H5E_DATASET, H5E_CANTALLOC, FAIL, "unable to allocate memory for virtual dataset entry list")
        layout->storage.u.virt.list_nalloc = layout->storage.u.virt.list_nused;

        /* Copy the list entries, though set source_dset.dset and sub_dset to
         * NULL */
        for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
            /* Copy virtual selection */
            if(NULL == (layout->storage.u.virt.list[i].source_dset.virtual_select
                    = H5S_copy(orig_list[i].source_dset.virtual_select, FALSE, TRUE)))
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")

            /* Copy original source names */
            if(NULL == (layout->storage.u.virt.list[i].source_file_name
                    = HDstrdup(orig_list[i].source_file_name)))
                HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source file name")
            if(NULL == (layout->storage.u.virt.list[i].source_dset_name
                    = HDstrdup(orig_list[i].source_dset_name)))
                HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source dataset name")

            /* Copy source selection */
            if(NULL == (layout->storage.u.virt.list[i].source_select
                    = H5S_copy(orig_list[i].source_select, FALSE, TRUE)))
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy source selection")

            /* Initialize clipped selections */
            if(orig_list[i].unlim_dim_virtual < 0) {
                layout->storage.u.virt.list[i].source_dset.clipped_source_select = layout->storage.u.virt.list[i].source_select;
                layout->storage.u.virt.list[i].source_dset.clipped_virtual_select = layout->storage.u.virt.list[i].source_dset.virtual_select;
            } /* end if */

            /* Copy parsed names */
            if(H5D__virtual_copy_parsed_name(&layout->storage.u.virt.list[i].parsed_source_file_name, orig_list[i].parsed_source_file_name) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy parsed source file name")
            layout->storage.u.virt.list[i].psfn_static_strlen = orig_list[i].psfn_static_strlen;
            layout->storage.u.virt.list[i].psfn_nsubs = orig_list[i].psfn_nsubs;
            if(H5D__virtual_copy_parsed_name(&layout->storage.u.virt.list[i].parsed_source_dset_name, orig_list[i].parsed_source_dset_name) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy parsed source dataset name")
            layout->storage.u.virt.list[i].psdn_static_strlen = orig_list[i].psdn_static_strlen;
            layout->storage.u.virt.list[i].psdn_nsubs = orig_list[i].psdn_nsubs;

            /* Copy source names in source dset or add reference as appropriate
             */
            if(orig_list[i].source_dset.file_name) {
                if(orig_list[i].source_dset.file_name
                        == orig_list[i].source_file_name)
                    layout->storage.u.virt.list[i].source_dset.file_name = layout->storage.u.virt.list[i].source_file_name;
                else if(orig_list[i].parsed_source_file_name
                        && (orig_list[i].source_dset.file_name
                        != orig_list[i].parsed_source_file_name->name_segment)) {
                    HDassert(layout->storage.u.virt.list[i].parsed_source_file_name);
                    HDassert(layout->storage.u.virt.list[i].parsed_source_file_name->name_segment);
                    layout->storage.u.virt.list[i].source_dset.file_name = layout->storage.u.virt.list[i].parsed_source_file_name->name_segment;
                } /* end if */
                else
                    if(NULL == (layout->storage.u.virt.list[i].source_dset.file_name
                            = HDstrdup(orig_list[i].source_dset.file_name)))
                        HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source file name")
            } /* end if */
            if(orig_list[i].source_dset.dset_name) {
                if(orig_list[i].source_dset.dset_name
                        == orig_list[i].source_dset_name)
                    layout->storage.u.virt.list[i].source_dset.dset_name = layout->storage.u.virt.list[i].source_dset_name;
                else if(orig_list[i].parsed_source_dset_name
                        && (orig_list[i].source_dset.dset_name
                        != orig_list[i].parsed_source_dset_name->name_segment)) {
                    HDassert(layout->storage.u.virt.list[i].parsed_source_dset_name);
                    HDassert(layout->storage.u.virt.list[i].parsed_source_dset_name->name_segment);
                    layout->storage.u.virt.list[i].source_dset.dset_name = layout->storage.u.virt.list[i].parsed_source_dset_name->name_segment;
                } /* end if */
                else
                    if(NULL == (layout->storage.u.virt.list[i].source_dset.dset_name
                            = HDstrdup(orig_list[i].source_dset.dset_name)))
                        HGOTO_ERROR(H5E_DATASET, H5E_RESOURCE, FAIL, "unable to duplicate source dataset name")
            } /* end if */

            /* Copy other fields in entry */
            layout->storage.u.virt.list[i].unlim_dim_source = orig_list[i].unlim_dim_source;
            layout->storage.u.virt.list[i].unlim_dim_virtual = orig_list[i].unlim_dim_virtual;
            layout->storage.u.virt.list[i].unlim_extent_source = orig_list[i].unlim_extent_source;
            layout->storage.u.virt.list[i].unlim_extent_virtual = orig_list[i].unlim_extent_virtual;
            layout->storage.u.virt.list[i].clip_size_source = orig_list[i].clip_size_source;
            layout->storage.u.virt.list[i].clip_size_virtual = orig_list[i].clip_size_virtual;
            layout->storage.u.virt.list[i].source_space_status = orig_list[i].source_space_status;
            layout->storage.u.virt.list[i].virtual_space_status = orig_list[i].virtual_space_status;
        } /* end for */
    } /* end if */
    else {
        /* Zero out other fields related to list, just to be sure */
        layout->storage.u.virt.list = NULL;
        layout->storage.u.virt.list_nalloc = 0;
    } /* end else */

    /* Copy property lists */
    if(orig_source_fapl >= 0) {
        if(NULL == (plist = (H5P_genplist_t *)H5I_object_verify(orig_source_fapl, H5I_GENPROP_LST)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
        if((layout->storage.u.virt.source_fapl = H5P_copy_plist(plist, FALSE)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy fapl")
    } /* end if */
    if(orig_source_dapl >= 0) {
        if(NULL == (plist = (H5P_genplist_t *)H5I_object_verify(orig_source_dapl, H5I_GENPROP_LST)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
        if((layout->storage.u.virt.source_dapl = H5P_copy_plist(plist, FALSE)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy dapl")
    } /* end if */

    /* New layout is not fully initialized */
    layout->storage.u.virt.init = FALSE;

done:
    /* Release allocated resources on failure */
    if(ret_value < 0)
        if(H5D__virtual_reset_layout(layout) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "unable to reset virtual layout")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_copy_layout() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_reset_layout
 *
 * Purpose:     Frees internal structures in a virtual storage layout
 *              message in memory.  This function is safe to use on
 *              incomplete structures (for recovery from failure) provided
 *              the internal structures are initialized with all bytes set
 *              to 0.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 11, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_reset_layout(H5O_layout_t *layout)
{
    size_t          i, j;
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    HDassert(layout);
    HDassert(layout->type == H5D_VIRTUAL);

    /* Free the list entries.  Note we always attempt to free everything even in
     * the case of a failure.  Because of this, and because we free the list
     * afterwards, we do not need to zero out the memory in the list. */
    for(i = 0; i < layout->storage.u.virt.list_nused; i++) {
        /* Free source_dset */
        if(H5D__virtual_reset_source_dset(&layout->storage.u.virt.list[i], &layout->storage.u.virt.list[i].source_dset) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "unable to reset source dataset")

        /* Free original source names */
        (void)H5MM_xfree(layout->storage.u.virt.list[i].source_file_name);
        (void)H5MM_xfree(layout->storage.u.virt.list[i].source_dset_name);

        /* Free sub_dset */
        for(j = 0; j < layout->storage.u.virt.list[i].sub_dset_nalloc; j++)
            if(H5D__virtual_reset_source_dset(&layout->storage.u.virt.list[i], &layout->storage.u.virt.list[i].sub_dset[j]) < 0)
                HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "unable to reset source dataset")
        layout->storage.u.virt.list[i].sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_xfree(layout->storage.u.virt.list[i].sub_dset);

        /* Free source_select */
        if(layout->storage.u.virt.list[i].source_select)
            if(H5S_close(layout->storage.u.virt.list[i].source_select) < 0)
                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release source selection")

        /* Free parsed_source_file_name */
        H5D_virtual_free_parsed_name(layout->storage.u.virt.list[i].parsed_source_file_name);

        /* Free parsed_source_dset_name */
        H5D_virtual_free_parsed_name(layout->storage.u.virt.list[i].parsed_source_dset_name);
    } /* end for */

    /* Free the list */
    layout->storage.u.virt.list = (H5O_storage_virtual_ent_t *)H5MM_xfree(layout->storage.u.virt.list);
    layout->storage.u.virt.list_nalloc = (size_t)0;
    layout->storage.u.virt.list_nused = (size_t)0;
    (void)HDmemset(layout->storage.u.virt.min_dims, 0, sizeof(layout->storage.u.virt.min_dims));

    /* Close access property lists */
    if(layout->storage.u.virt.source_fapl >= 0) {
        if(H5I_dec_ref(layout->storage.u.virt.source_fapl) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "can't close source fapl")
        layout->storage.u.virt.source_fapl = -1;
    } /* end if */
    if(layout->storage.u.virt.source_dapl >= 0) {
        if(H5I_dec_ref(layout->storage.u.virt.source_dapl) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "can't close source dapl")
        layout->storage.u.virt.source_dapl = -1;
    } /* end if */

    /* The list is no longer initialized */
    layout->storage.u.virt.init = FALSE;

    /* Note the lack of a done: label.  This is because there are no HGOTO_ERROR
     * calls.  If one is added, a done: label must also be added */
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_reset_layout() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_copy
 *
 * Purpose:     Copy virtual storage raw data from SRC file to DST file.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_copy(H5F_t H5_ATTR_UNUSED *f_dst, H5O_layout_t *layout_dst,
    hid_t H5_ATTR_UNUSED dxpl_id)
{
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE

    /* Copy message in memory */
    if(H5D__virtual_copy_layout(layout_dst) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual layout")

#ifdef NOT_YET
    /* Check for copy to the same file */
    if(f_dst == f_src) {
        /* Increase reference count on global heap object */
        if((heap_rc = H5HG_link(f_dst, dxpl_id, (H5HG_t *)&(layout_dst->u.virt.serial_list_hobjid), 1)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTMODIFY, FAIL, "unable to adjust global heap refence count")
    } /* end if */
    else
#endif /* NOT_YET */
    {
        /* Reset global heap id so a new heap object is created when the message
         * is flushed */
        layout_dst->storage.u.virt.serial_list_hobjid.addr = HADDR_UNDEF;
        layout_dst->storage.u.virt.serial_list_hobjid.idx = (size_t)0;
    } /* end block/else */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_copy() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_delete
 *
 * Purpose:     Delete the file space for a virtual dataset
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_delete(H5F_t *f, hid_t dxpl_id, H5O_storage_t *storage)
{
#ifdef NOT_YET
    int heap_rc;                /* Reference count of global heap object */
#endif  /* NOT_YET */
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    HDassert(f);
    HDassert(storage);
    HDassert(storage->type == H5D_VIRTUAL);

    /* Check for global heap block */
    if(storage->u.virt.serial_list_hobjid.addr != HADDR_UNDEF) {
#ifdef NOT_YET
        /* Unlink the global heap block */
        if((heap_rc = H5HG_link(f, dxpl_id, (H5HG_t *)&(storage->u.virt.serial_list_hobjid), -1)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTMODIFY, FAIL, "unable to adjust global heap refence count")
        if(heap_rc == 0)
#endif /* NOT_YET */
            /* Delete the global heap block */
            if(H5HG_remove(f, dxpl_id, (H5HG_t *)&(storage->u.virt.serial_list_hobjid)) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTREMOVE, FAIL, "unable to remove heap object")
    } /* end if */

    /* Clear global heap ID in storage */
    storage->u.virt.serial_list_hobjid.addr = HADDR_UNDEF;
    storage->u.virt.serial_list_hobjid.idx = 0;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_delete */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_open_source_dset
 *
 * Purpose:     Attempts to open a source dataset.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              March 6, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_open_source_dset(const H5D_t *vdset,
    H5O_storage_virtual_ent_t *virtual_ent,
    H5O_storage_virtual_srcdset_t *source_dset, hid_t dxpl_id)
{
    H5F_t       *src_file = NULL;       /* Source file */
    hbool_t     src_file_open = FALSE;  /* Whether we have opened and need to close src_file */
    H5G_loc_t   src_root_loc;           /* Object location of source file root group */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(vdset);
    HDassert(source_dset);
    HDassert(!source_dset->dset);
    HDassert(source_dset->file_name);
    HDassert(source_dset->dset_name);

    /* Check if we need to open the source file */
    if(HDstrcmp(source_dset->file_name, ".")) {
        /* Open the source file */
        if(NULL == (src_file = H5F_open(source_dset->file_name, H5F_INTENT(vdset->oloc.file) & H5F_ACC_RDWR, H5P_FILE_CREATE_DEFAULT, vdset->shared->layout.storage.u.virt.source_fapl, dxpl_id)))
            H5E_clear_stack(NULL); /* Quick hack until proper support for H5Fopen with missing file is implemented */
        else
            src_file_open = TRUE;
    } /* end if */
    else
        /* Source file is ".", use the virtual dataset's file */
        src_file = vdset->oloc.file;

    if(src_file) {
        /* Set up the root group in the destination file */
        if(NULL == (src_root_loc.oloc = H5G_oloc(H5G_rootof(src_file))))
            HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, FAIL, "unable to get object location for root group")
        if(NULL == (src_root_loc.path = H5G_nameof(H5G_rootof(src_file))))
            HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, FAIL, "unable to get path for root group")

        /* Open the source dataset */
        if(NULL == (source_dset->dset = H5D__open_name(&src_root_loc, source_dset->dset_name, vdset->shared->layout.storage.u.virt.source_dapl, dxpl_id))) {
            H5E_clear_stack(NULL); /* Quick hack until proper support for H5Dopen with missing file is implemented */

            /* Dataset does not exist */
            source_dset->dset_exists = FALSE;
        } /* end if */
        else {
            /* Dataset exists */
            source_dset->dset_exists = TRUE;

            /* Patch the source selection if necessary */
            if(virtual_ent->source_space_status != H5O_VIRTUAL_STATUS_CORRECT) {
                if(H5S_extent_copy(virtual_ent->source_select, source_dset->dset->shared->space) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy source dataspace extent")
                virtual_ent->source_space_status = H5O_VIRTUAL_STATUS_CORRECT;
            } /* end if */
        } /* end else */
    } /* end if */

done:
    /* Close source file */
    if(src_file_open)
        if(H5F_try_close(src_file) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CANTCLOSEFILE, FAIL, "can't close source file")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_open_source_dset() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_reset_source_dset
 *
 * Purpose:     Frees space referenced by a source dataset struct.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 20, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_reset_source_dset(H5O_storage_virtual_ent_t *virtual_ent,
    H5O_storage_virtual_srcdset_t *source_dset)
{
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(source_dset);

    /* Free dataset */
    if(source_dset->dset) {
        if(H5D_close(source_dset->dset) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to close source dataset")
        source_dset->dset = NULL;
    } /* end if */

    /* Free file name */
    if(virtual_ent->parsed_source_file_name
            && (source_dset->file_name
            != virtual_ent->parsed_source_file_name->name_segment))
        source_dset->file_name = (char *)H5MM_xfree(source_dset->file_name);
    else
        HDassert((source_dset->file_name == virtual_ent->source_file_name)
                || (virtual_ent->parsed_source_file_name
                && (source_dset->file_name
                == virtual_ent->parsed_source_file_name->name_segment))
                || !source_dset->file_name);

    /* Free dataset name */
    if(virtual_ent->parsed_source_dset_name
            && (source_dset->dset_name
            != virtual_ent->parsed_source_dset_name->name_segment))
        source_dset->dset_name = (char *)H5MM_xfree(source_dset->dset_name);
    else
        HDassert((source_dset->dset_name == virtual_ent->source_dset_name)
                || (virtual_ent->parsed_source_dset_name
                && (source_dset->dset_name
                == virtual_ent->parsed_source_dset_name->name_segment))
                || !source_dset->dset_name);

    /* Free clipped virtual selection */
    if(source_dset->clipped_virtual_select) {
        if(source_dset->clipped_virtual_select != source_dset->virtual_select)
            if(H5S_close(source_dset->clipped_virtual_select) < 0)
                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual selection")
        source_dset->clipped_virtual_select = NULL;
    } /* end if */

    /* Free virtual selection */
    if(source_dset->virtual_select) {
        if(H5S_close(source_dset->virtual_select) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release virtual selection")
        source_dset->virtual_select = NULL;
    } /* end if */

    /* Free clipped source selection */
    if(source_dset->clipped_source_select) {
        if(source_dset->clipped_source_select != virtual_ent->source_select)
            if(H5S_close(source_dset->clipped_source_select) < 0)
                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source selection")
        source_dset->clipped_source_select = NULL;
    } /* end if */

    /* The projected memory space should never exist when this function is
     * called */
    HDassert(!source_dset->projected_mem_space);

    /* Note the lack of a done: label.  This is because there are no HGOTO_ERROR
     * calls.  If one is added, a done: label must also be added */
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_reset_source_dset() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_str_append
 *
 * Purpose:     Appends src_len bytes of the string src to the position *p
 *              in the buffer *buf (allocating *buf if necessary).
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 19, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_str_append(const char *src, size_t src_len, char **p, char **buf,
    size_t *buf_size)
{
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(src);
    HDassert(src_len > 0);
    HDassert(p);
    HDassert(buf);
    HDassert(*p >= *buf);
    HDassert(buf_size);

    /* Allocate or extend buffer if necessary */
    if(!*buf) {
        HDassert(!*p);
        HDassert(*buf_size == 0);

        /* Allocate buffer */
        if(NULL == (*buf = (char *)H5MM_malloc(src_len + (size_t)1)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name segment struct")
        *buf_size = src_len + (size_t)1;
        *p = *buf;
    } /* end if */
    else {
        size_t p_offset = (size_t)(*p - *buf); /* Offset of p within buf */

        /* Extend buffer if necessary */
        if((p_offset + src_len + (size_t)1) > *buf_size) {
            char *tmp_buf;
            size_t tmp_buf_size;

            /* Calculate new size of buffer */
            tmp_buf_size = MAX(p_offset + src_len + (size_t)1,
                    *buf_size * (size_t)2);

            /* Reallocate buffer */
            if(NULL == (tmp_buf = (char *)H5MM_realloc(*buf, tmp_buf_size)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to reallocate name segment buffer")
            *buf = tmp_buf;
            *buf_size = tmp_buf_size;
            *p = *buf + p_offset;
        } /* end if */
    } /* end else */

    /* Copy string to *p.  Note that since src in not NULL terminated, we must
     * use memcpy */
    (void)HDmemcpy(*p, src, src_len);

    /* Advance *p */
    *p += src_len;

    /* Add NULL terminator */
    **p = '\0';

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5D__virtual_str_append() */


/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_parse_source_name
 *
 * Purpose:     Parses a source file or dataset name.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 18, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_parse_source_name(const char *source_name,
    H5O_storage_virtual_name_seg_t **parsed_name, size_t *static_strlen,
    size_t *nsubs)
{
    H5O_storage_virtual_name_seg_t *tmp_parsed_name = NULL;
    H5O_storage_virtual_name_seg_t **tmp_parsed_name_p = &tmp_parsed_name;
    size_t      tmp_static_strlen;
    size_t      tmp_strlen;
    size_t      tmp_nsubs = 0;
    const char  *p;
    const char  *pct;
    char        *name_seg_p = NULL;
    size_t      name_seg_size = 0;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Sanity check */
    HDassert(source_name);
    HDassert(parsed_name);
    HDassert(static_strlen);
    HDassert(nsubs);

    /* Initialize p and tmp_static_strlen */
    p = source_name;
    tmp_static_strlen = tmp_strlen = HDstrlen(source_name);

    /* Iterate over name */
    /* Note this will not work with UTF-8!  We should support this eventually
     * -NAF 5/18/2015 */
    while((pct = HDstrchr(p, '%'))) {
        HDassert(pct >= p);

        /* Allocate name segment struct if necessary */
        if(!*tmp_parsed_name_p)
            if(NULL == (*tmp_parsed_name_p = H5FL_CALLOC(H5O_storage_virtual_name_seg_t)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name segment struct")

        /* Check for type of format specifier */
        if(pct[1] == 'b') {
            /* Check for blank string before specifier */
            if(pct != p)
                /* Append string to name segment */
                if(H5D__virtual_str_append(p, (size_t)(pct - p), &name_seg_p, &(*tmp_parsed_name_p)->name_segment,
    &name_seg_size) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to append name segment")

            /* Update other variables */
            tmp_parsed_name_p = &(*tmp_parsed_name_p)->next;
            tmp_static_strlen -= 2;
            tmp_nsubs++;
            name_seg_p = NULL;
            name_seg_size = 0;
        } /* end if */
        else if(pct[1] == '%') {
            /* Append string to name segment (include first '%') */
            if(H5D__virtual_str_append(p, (size_t)(pct - p) + (size_t)1, &name_seg_p, &(*tmp_parsed_name_p)->name_segment,
&name_seg_size) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to append name segment")

            /* Update other variables */
            tmp_static_strlen -= 1;
        } /* end else */
        else
            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid format specifier")

        p = pct + 2;
    } /* end while */

    /* Copy last segment of name, if any, unless the parsed name was not
     * allocated */
    if(tmp_parsed_name) {
        HDassert(p >= source_name);
        if(*p == '\0')
            HDassert((size_t)(p - source_name) == tmp_strlen);
        else {
            HDassert((size_t)(p - source_name) < tmp_strlen);

            /* Allocate name segment struct if necessary */
            if(!*tmp_parsed_name_p)
                if(NULL == (*tmp_parsed_name_p = H5FL_CALLOC(H5O_storage_virtual_name_seg_t)))
                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name segment struct")

            /* Append string to name segment */
            if(H5D__virtual_str_append(p, tmp_strlen - (size_t)(p - source_name), &name_seg_p, &(*tmp_parsed_name_p)->name_segment,
    &name_seg_size) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to append name segment")
        } /* end else */
    } /* end if */

    /* Set return values */
    *parsed_name = tmp_parsed_name;
    tmp_parsed_name = NULL;
    *static_strlen = tmp_static_strlen;
    *nsubs = tmp_nsubs;

done:
    if(tmp_parsed_name) {
        HDassert(ret_value < 0);
        H5D_virtual_free_parsed_name(tmp_parsed_name);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_parse_source_name() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_copy_parsed_name
 *
 * Purpose:     Deep copies a parsed source file or dataset name.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 19, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_copy_parsed_name(H5O_storage_virtual_name_seg_t **dst,
    H5O_storage_virtual_name_seg_t *src)
{
    H5O_storage_virtual_name_seg_t *tmp_dst = NULL;
    H5O_storage_virtual_name_seg_t *p_src = src;
    H5O_storage_virtual_name_seg_t **p_dst = &tmp_dst;
    herr_t          ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(dst);

    /* Walk over parsed name, duplicating it */
    while(p_src) {
        /* Allocate name segment struct */
        if(NULL == (*p_dst = H5FL_CALLOC(H5O_storage_virtual_name_seg_t)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name segment struct")

        /* Duplicate name segment */
        if(p_src->name_segment) {
            if(NULL == ((*p_dst)->name_segment = HDstrdup(p_src->name_segment)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to duplicate name segment")
        } /* end if */

        /* Advance pointers */
        p_src = p_src->next;
        p_dst = &(*p_dst)->next;
    } /* end while */

    /* Set dst */
    *dst = tmp_dst;
    tmp_dst = NULL;

done:
    if(tmp_dst) {
        HDassert(ret_value < 0);
        H5D_virtual_free_parsed_name(tmp_dst);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_copy_parsed_name() */


/*-------------------------------------------------------------------------
 * Function:    H5D_virtual_free_parsed_name
 *
 * Purpose:     Frees the provided parsed name.
 *
 * Return:      void
 *
 * Programmer:  Neil Fortner
 *              May 19, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D_virtual_free_parsed_name(H5O_storage_virtual_name_seg_t *name_seg)
{
    H5O_storage_virtual_name_seg_t *next_seg;
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Walk name segments, freeing them */
    while(name_seg) {
        (void)H5MM_xfree(name_seg->name_segment);
        next_seg = name_seg->next;
        (void)H5FL_FREE(H5O_storage_virtual_name_seg_t, name_seg);
        name_seg = next_seg;
    } /* end while */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D_virtual_free_parsed_name() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_build_source_name
 *
 * Purpose:     Builds a source file or dataset name from a parsed name.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 18, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_build_source_name(char *source_name,
    const H5O_storage_virtual_name_seg_t *parsed_name, size_t static_strlen,
    size_t nsubs, hsize_t blockno, char **built_name)
{
    char        *tmp_name = NULL;       /* Name buffer */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(source_name);
    HDassert(built_name);

    /* Check for static name */
    if(nsubs == 0) {
        if(parsed_name)
            *built_name = parsed_name->name_segment;
        else
            *built_name = source_name;
    } /* end if */
    else {
        const H5O_storage_virtual_name_seg_t *name_seg = parsed_name;
        char *p;
        hsize_t blockno_down = blockno;
        size_t blockno_len = 1;
        size_t name_len;
        size_t name_len_rem;
        size_t seg_len;
        size_t nsubs_rem = nsubs;

        HDassert(parsed_name);

        /* Calculate length of printed block number */
        do {
            blockno_down /= (hsize_t)10;
            if(blockno_down == 0)
                break;
            blockno_len++;
        } while(1);

        /* Calculate length of name buffer */
        name_len_rem = name_len = static_strlen + (nsubs * blockno_len) + (size_t)1;

        /* Allocate name buffer */
        if(NULL == (tmp_name = (char *)H5MM_malloc(name_len)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name buffer")
        p = tmp_name;

        /* Build name */
        do {
            /* Add name segment */
            if(name_seg->name_segment) {
                seg_len = HDstrlen(name_seg->name_segment);
                HDassert(seg_len > 0);
                HDassert(seg_len < name_len_rem);
                HDstrncpy(p, name_seg->name_segment, name_len_rem);
                name_len_rem -= seg_len;
                p += seg_len;
            } /* end if */

            /* Add block number */
            if(nsubs_rem > 0) {
                HDassert(blockno_len < name_len_rem);
                if(HDsnprintf(p, name_len_rem, "%llu", (long long unsigned)blockno) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write block number to string")
                name_len_rem -= blockno_len;
                p += blockno_len;
                nsubs_rem--;
            } /* end if */

            /* Advance name_seg */
            name_seg = name_seg->next;
        } while(name_seg);

        /* Assign built_name */
        *built_name = tmp_name;
        tmp_name = NULL;
    } /* end else */

done:
    if(tmp_name) {
        HDassert(ret_value < 0);
        H5MM_free(tmp_name);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_build_source_name() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_set_extent_unlim
 *
 * Purpose:     Sets the extent of the virtual dataset by checking the
 *              extents of source datasets where an unlimited selection
 *              matching.  Dimensions that are not unlimited in any
 *              virtual mapping selections are not affected.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              April 22, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_set_extent_unlim(const H5D_t *dset, hid_t dxpl_id)
{
    H5O_storage_virtual_t *storage;
    hsize_t     new_dims[H5S_MAX_RANK];
    hsize_t     curr_dims[H5S_MAX_RANK];
    hsize_t     clip_size;
    int         rank;
    hbool_t     changed = FALSE;        /* Whether the VDS extent changed */
    size_t      i, j;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    HDassert(dset);
    HDassert(dset->shared->layout.storage.type == H5D_VIRTUAL);
    storage = &dset->shared->layout.storage.u.virt;
    HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));

    /* Get rank of VDS */
    if((rank = H5S_GET_EXTENT_NDIMS(dset->shared->space)) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get number of dimensions")

    /* Initialize new_dims to HSIZE_UNDEF */
    for(i = 0; i < (size_t)rank; i++)
        new_dims[i] = HSIZE_UNDEF;

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nalloc; i++)
        /* Check for unlimited dimension */
        if(storage->list[i].unlim_dim_virtual >= 0) {
            /* Check for "printf" source dataset resolution */
            if(storage->list[i].unlim_dim_source >= 0 ) {
                /* Non-printf mapping */
                /* Open source dataset */
                if(!storage->list[i].source_dset.dset)
                    if(H5D__virtual_open_source_dset(dset, &storage->list[i], &storage->list[i].source_dset, dxpl_id) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")

                /* Check if source dataset is open */
                if(storage->list[i].source_dset.dset) {
                    /* Retrieve current source dataset extent and patch mapping
                     */
                    if(H5S_extent_copy(storage->list[i].source_select, storage->list[i].source_dset.dset->shared->space) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy source dataspace extent")

                    /* Get source space dimenstions */
                    if(H5S_get_simple_extent_dims(storage->list[i].source_select, curr_dims, NULL) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get source space dimensions")

                    /* Check if the source extent in the unlimited dimension
                     * changed since the last time the VDS extent/mapping
                     * was updated */
                    if(curr_dims[storage->list[i].unlim_dim_source]
                            == storage->list[i].unlim_extent_source)
                        /* Use cached result for clip size */
                        clip_size = storage->list[i].clip_size_virtual;
                    else {
                        /* Get size that virtual selection would be clipped to
                         * to match size of source selection within source
                         * extent */
                        clip_size = H5S_hyper_get_clip_extent_match(storage->list[i].source_dset.virtual_select, storage->list[i].source_select, curr_dims[storage->list[i].unlim_dim_source], storage->view == H5D_VDS_FIRST_MISSING);

                        /* If we are setting the extent by the last available
                         * data, clip virtual_select and source_select.  Note
                         * that if we used the cached clip_size above or it
                         * happens to be the same, the virtual selection will
                         * already be clipped to the correct size.  Likewise,
                         * if we used the cached clip_size the source selection
                         * will already be correct. */
                        if(storage->view == H5D_VDS_LAST_AVAILABLE) {
                            if(clip_size != storage->list[i].clip_size_virtual) {
                                /* Close previous clipped virtual selection, if
                                 * any */
                                if(storage->list[i].source_dset.clipped_virtual_select) {
                                    HDassert(storage->list[i].source_dset.clipped_virtual_select
                                            != storage->list[i].source_dset.virtual_select);
                                    if(H5S_close(storage->list[i].source_dset.clipped_virtual_select) < 0)
                                        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual dataspace")
                                } /* end if */

                                /* Copy virtual selection */
                                if(NULL == (storage->list[i].source_dset.clipped_virtual_select = H5S_copy(storage->list[i].source_dset.virtual_select, FALSE, TRUE)))
                                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")

                                /* Clip virtual selection */
                                if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_virtual_select, clip_size))
                                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")
                            } /* end if */

                            /* Close previous clipped source selection, if any
                             */
                            if(storage->list[i].source_dset.clipped_source_select) {
                                HDassert(storage->list[i].source_dset.clipped_source_select
                                        != storage->list[i].source_select);
                                if(H5S_close(storage->list[i].source_dset.clipped_source_select) < 0)
                                    HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source dataspace")
                            } /* end if */

                            /* Copy source selection */
                            if(NULL == (storage->list[i].source_dset.clipped_source_select = H5S_copy(storage->list[i].source_select, FALSE, TRUE)))
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy source selection")

                            /* Clip source selection */
                            if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_source_select, curr_dims[storage->list[i].unlim_dim_source]))
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")
                        } /* end if */

                        /* Update cached values unlim_extent_source and 
                         * clip_size_virtual */
                        storage->list[i].unlim_extent_source = curr_dims[storage->list[i].unlim_dim_source];
                        storage->list[i].clip_size_virtual = clip_size;
                    } /* end else */
                } /* end if */
                else
                    clip_size = 0;
            } /* end if */
            else {
                /* printf mapping */
                hsize_t first_missing = 0;  /* First missing dataset in the current block of missing datasets */

                /* Search for source datasets */
                HDassert(storage->printf_gap != HSIZE_UNDEF);
                for(j = 0; j <= (storage->printf_gap + first_missing); j++) {
                    /* Check for running out of space in sub_dset array */
                    if(j >= (hsize_t)storage->list[i].sub_dset_nalloc) {
                        if(storage->list[i].sub_dset_nalloc == 0) {
                            /* Allocate sub_dset */
                            if(NULL == (storage->list[i].sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_calloc(H5D_VIRTUAL_DEF_SUB_DSET_SIZE * sizeof(H5O_storage_virtual_srcdset_t))))
                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate sub dataset array")
                            storage->list[i].sub_dset_nalloc = H5D_VIRTUAL_DEF_SUB_DSET_SIZE;
                        } /* end if */
                        else {
                            H5O_storage_virtual_srcdset_t *tmp_sub_dset;

                            /* Extend sub_dset */
                            if(NULL == (tmp_sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_realloc(storage->list[i].sub_dset, 2 * storage->list[i].sub_dset_nalloc * sizeof(H5O_storage_virtual_srcdset_t))))
                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend sub dataset array")
                            storage->list[i].sub_dset = tmp_sub_dset;

                            /* Clear new space in sub_dset */
                            (void)HDmemset(&storage->list[i].sub_dset[storage->list[i].sub_dset_nalloc], 0, storage->list[i].sub_dset_nalloc * sizeof(H5O_storage_virtual_srcdset_t));

                            /* Update sub_dset_nalloc */
                            storage->list[i].sub_dset_nalloc *= 2;
                        } /* end else */
                    } /* end if */

                    /* Check if the dataset was already opened */
                    if(storage->list[i].sub_dset[j].dset_exists)
                        first_missing = j + 1;
                    else {
                        /* Resolve file name */
                        if(!storage->list[i].sub_dset[j].file_name)
                            if(H5D__virtual_build_source_name(storage->list[i].source_file_name, storage->list[i].parsed_source_file_name, storage->list[i].psfn_static_strlen, storage->list[i].psfn_nsubs, j, &storage->list[i].sub_dset[j].file_name) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to build source file name")

                        /* Resolve dset name */
                        if(!storage->list[i].sub_dset[j].dset_name)
                            if(H5D__virtual_build_source_name(storage->list[i].source_dset_name, storage->list[i].parsed_source_dset_name, storage->list[i].psdn_static_strlen, storage->list[i].psdn_nsubs, j, &storage->list[i].sub_dset[j].dset_name) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to build source dataset name")

                        /* Resolve virtual selection for block */
                        if(!storage->list[i].sub_dset[j].virtual_select)
                            if(NULL == (storage->list[i].sub_dset[j].virtual_select = H5S_hyper_get_unlim_block(storage->list[i].source_dset.virtual_select, j)))
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get block in unlimited selection")

                        /* Initialize clipped selections */
                        if(!storage->list[i].sub_dset[j].clipped_source_select)
                            storage->list[i].sub_dset[j].clipped_source_select = storage->list[i].source_select;
                        if(!storage->list[i].sub_dset[j].clipped_virtual_select)
                            storage->list[i].sub_dset[j].clipped_virtual_select = storage->list[i].sub_dset[j].virtual_select;

                        /* Open source dataset */
                        if(H5D__virtual_open_source_dset(dset, &storage->list[i], &storage->list[i].sub_dset[j], dxpl_id) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")

                        if(storage->list[i].sub_dset[j].dset) {
                            /* Update first_missing */
                            first_missing = j + 1;

                            /* Close source dataset so we don't have huge
                             * numbers of datasets open */
                            if(H5D_close(storage->list[i].sub_dset[j].dset) < 0)
                                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to close source dataset")
                            storage->list[i].sub_dset[j].dset = NULL;
                        } /* end if */
                    } /* end else */
                } /* end for */

                /* Check if the size changed */
                if((first_missing == (hsize_t)storage->list[i].sub_dset_nused)
                        && (storage->list[i].clip_size_virtual != HSIZE_UNDEF))
                    /* Use cached clip_size */
                    clip_size = storage->list[i].clip_size_virtual;
                else {
                    /* Check for no datasets */
                    if(first_missing == 0)
                        /* Set clip size to 0 */
                        clip_size = (hsize_t)0;
                    else {
                        hsize_t         bounds_start[H5S_MAX_RANK];
                        hsize_t         bounds_end[H5S_MAX_RANK];

                        /* Get clip size from selection */
                        if(storage->view == H5D_VDS_LAST_AVAILABLE) {
                            /* Get bounds from last valid virtual selection */
                            if(H5S_SELECT_BOUNDS(storage->list[i].sub_dset[first_missing - (hsize_t)1].virtual_select, bounds_start, bounds_end) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")

                            /* Set clip_size to bounds_end in unlimited
                             * dimension */
                            clip_size = bounds_end[storage->list[i].unlim_dim_virtual]
                                    + (hsize_t)1;
                        } /* end if */
                        else {
                            /* Get bounds from first missing virtual selection
                             */
                            if(H5S_SELECT_BOUNDS(storage->list[i].sub_dset[first_missing].virtual_select, bounds_start, bounds_end) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")

                            /* Set clip_size to bounds_start in unlimited
                             * dimension */
                            clip_size = bounds_start[storage->list[i].unlim_dim_virtual];
                        } /* end else */
                    } /* end else */

                    /* Set sub_dset_nused and clip_size_virtual */
                    storage->list[i].sub_dset_nused = (size_t)first_missing;
                    storage->list[i].clip_size_virtual = clip_size;
                } /* end else */
            } /* end else */

            /* Update new_dims */
            if((new_dims[storage->list[i].unlim_dim_virtual] == HSIZE_UNDEF)
                    || (storage->view == H5D_VDS_FIRST_MISSING ? (clip_size
                    < (hsize_t)new_dims[storage->list[i].unlim_dim_virtual])
                    : (clip_size
                    > (hsize_t)new_dims[storage->list[i].unlim_dim_virtual])))
                new_dims[storage->list[i].unlim_dim_virtual] = clip_size;
        } /* end if */

    /* Get current VDS dimensions */
    if(H5S_get_simple_extent_dims(dset->shared->space, curr_dims, NULL) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get VDS dimensions")

    /* Calculate new extent */
    for(i = 0; i < (size_t)rank; i++) {
        if(new_dims[i] == HSIZE_UNDEF)
            new_dims[i] = curr_dims[i];
        else if(new_dims[i] < storage->min_dims[i])
            new_dims[i] = storage->min_dims[i];
        if(new_dims[i] != curr_dims[i])
            changed = TRUE;
    } /* end for */

    /* Update extent if it changed */
    if(changed) {
        /* Update VDS extent */
        if(H5S_set_extent(dset->shared->space, new_dims) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")

        /* Mark the space as dirty, for later writing to the file */
        if(H5F_INTENT(dset->oloc.file) & H5F_ACC_RDWR) 
            if(H5D__mark(dset, dxpl_id, H5D_MARK_SPACE) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "unable to mark dataspace as dirty")
    } /* end if */

    /* If we did not change the VDS dimensions, there is nothing more to update
     */
    if(changed || (!storage->init && (storage->view == H5D_VDS_FIRST_MISSING))) {
        /* Iterate over mappings again to update source selections and virtual
         * mapping extents */
        for(i = 0; i < storage->list_nalloc; i++) {
            /* If there is an unlimited dimension, we are setting extent by the
             * minimum of mappings, and the virtual extent in the unlimited
             * dimension has changed since the last time the VDS extent/mapping
             * was updated, we must adjust the selections */
            if((storage->list[i].unlim_dim_virtual >= 0)
                    && (storage->view == H5D_VDS_FIRST_MISSING)
                    && (new_dims[storage->list[i].unlim_dim_virtual]
                    != storage->list[i].unlim_extent_virtual)) {
                /* Check for "printf" style mapping */
                if(storage->list[i].unlim_dim_source >= 0) {
                    /* Non-printf mapping */
                    /* Close previous clipped virtual selection, if any */
                    if(storage->list[i].source_dset.clipped_virtual_select) {
                        HDassert(storage->list[i].source_dset.clipped_virtual_select
                            != storage->list[i].source_dset.virtual_select);
                        if(H5S_close(storage->list[i].source_dset.clipped_virtual_select) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual dataspace")
                    } /* end if */

                    /* Copy virtual selection */
                    if(NULL == (storage->list[i].source_dset.clipped_virtual_select = H5S_copy(storage->list[i].source_dset.virtual_select, FALSE, TRUE)))
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")

                    /* Clip space to virtual extent */
                    if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_virtual_select, new_dims[storage->list[i].unlim_dim_source]))
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")

                    /* Get size that source selection will be clipped to to
                     * match size of virtual selection */
                    clip_size = H5S_hyper_get_clip_extent(storage->list[i].source_select, storage->list[i].source_dset.clipped_virtual_select, FALSE);

                    /* Check if the clip size changed */
                    if(clip_size != storage->list[i].clip_size_source) {
                        /* Close previous clipped source selection, if any */
                        if(storage->list[i].source_dset.clipped_source_select) {
                            HDassert(storage->list[i].source_dset.clipped_source_select
                                != storage->list[i].source_select);
                            if(H5S_close(storage->list[i].source_dset.clipped_source_select) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source dataspace")
                        } /* end if */

                        /* Copy source selection */
                        if(NULL == (storage->list[i].source_dset.clipped_source_select = H5S_copy(storage->list[i].source_select, FALSE, TRUE)))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy source selection")

                        /* Clip source selection */
                        if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_source_select, clip_size))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")

                        /* Update cached value clip_size_source */
                        storage->list[i].clip_size_source = clip_size;
                    } /* end if */
                } /* end if */
                else {
                    /* printf mapping */
                    hsize_t first_inc_block;
                    hbool_t partial_block;

                    /* Get index of first incomplete block in virtual
                     * selection */
                    first_inc_block = H5S_hyper_get_first_inc_block(storage->list[i].source_dset.virtual_select, new_dims[storage->list[i].unlim_dim_virtual], &partial_block);

                    /* Iterate over sub datasets */
                    for(j = 0; j < storage->list[i].sub_dset_nalloc; j++) {
                        /* Close previous clipped source selection, if any */
                        if(storage->list[i].sub_dset[j].clipped_source_select
                                != storage->list[i].source_select) {
                            if(storage->list[i].sub_dset[j].clipped_source_select)
                                if(H5S_close(storage->list[i].sub_dset[j].clipped_source_select) < 0)
                                    HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source dataspace")

                            /* Initialize clipped source selection to point to
                             * base source selection */
                            storage->list[i].sub_dset[j].clipped_source_select = storage->list[i].source_select;
                        } /* end if */

                        /* Close previous clipped virtual selection, if any */
                        if(storage->list[i].sub_dset[j].clipped_virtual_select
                                != storage->list[i].sub_dset[j].virtual_select) {
                            if(storage->list[i].sub_dset[j].clipped_virtual_select)
                                if(H5S_close(storage->list[i].sub_dset[j].clipped_virtual_select) < 0)
                                    HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual dataspace")

                            /* Initialize clipped virtual selection to point to
                             * unclipped virtual selection */
                            storage->list[i].sub_dset[j].clipped_virtual_select = storage->list[i].sub_dset[j].virtual_select;
                        } /* end if */

                        /* Only initialize clipped selections if it is a
                         * complete block, for incomplete blocks defer to
                         * H5D__virtual_pre_io() as we may not have a valid
                         * source extent here.  For unused blocks we will never
                         * need clipped selections (until the extent is
                         * recalculated in this function). */
                        if(j >= (size_t)first_inc_block) {
                            /* Clear clipped source and virtual selections */
                            storage->list[i].sub_dset[j].clipped_source_select = NULL;
                            storage->list[i].sub_dset[j].clipped_virtual_select = NULL;
                        } /* end if */
                    } /* end for */
                } /* end else */

                /* Update cached value unlim_extent_virtual */
                storage->list[i].unlim_extent_virtual = new_dims[storage->list[i].unlim_dim_virtual];
            } /* end if */

            /* Update top level virtual_select and clipped_virtual_select
             * extents */
            if(H5S_set_extent(storage->list[i].source_dset.virtual_select, new_dims) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
            if((storage->list[i].source_dset.clipped_virtual_select
                    != storage->list[i].source_dset.virtual_select)
                    && storage->list[i].source_dset.clipped_virtual_select)
                if(H5S_set_extent(storage->list[i].source_dset.clipped_virtual_select, new_dims) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")

            /* Update sub dataset virtual_select and clipped_virtual_select
             * extents */
            for(j = 0; j < storage->list[i].sub_dset_nalloc; j++)
                if(storage->list[i].sub_dset[j].virtual_select) {
                    if(H5S_set_extent(storage->list[i].sub_dset[j].virtual_select, new_dims) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
                    if((storage->list[i].sub_dset[j].clipped_virtual_select
                            != storage->list[i].sub_dset[j].virtual_select)
                            && storage->list[i].sub_dset[j].clipped_virtual_select)
                        if(H5S_set_extent(storage->list[i].sub_dset[j].clipped_virtual_select, new_dims) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
                } /* end if */
                else
                    HDassert(!storage->list[i].sub_dset[j].clipped_virtual_select);
        } /* end for */
    } /* end if */

    /* Mark layout as fully initialized */
    storage->init = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_set_extent_unlim() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_init_all
 *
 * Purpose:     Finishes initializing layout in preparation for I/O.
 *              Only necessary if H5D__virtual_set_extent_unlim() has not
 *              been called yet.  Initializes clipped_virtual_select and
 *              clipped_source_select for all mappings in this layout.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              August 10, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_init_all(const H5D_t *dset, hid_t dxpl_id)
{
    H5O_storage_virtual_t *storage;
    hsize_t     virtual_dims[H5S_MAX_RANK];
    hsize_t     source_dims[H5S_MAX_RANK];
    hsize_t     clip_size;
    size_t      i, j;
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(dset);
    HDassert(dset->shared->layout.storage.type == H5D_VIRTUAL);
    storage = &dset->shared->layout.storage.u.virt;
    HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));

    /* Get current VDS dimensions */
    if(H5S_get_simple_extent_dims(dset->shared->space, virtual_dims, NULL) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get VDS dimensions")

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nalloc; i++)
        /* Check for unlimited dimension */
        if(storage->list[i].unlim_dim_virtual >= 0) {
            /* Check for "printf" source dataset resolution */
            if(storage->list[i].unlim_dim_source >= 0 ) {
                /* Non-printf mapping */
                /* Open source dataset */
                if(!storage->list[i].source_dset.dset)
                    if(H5D__virtual_open_source_dset(dset, &storage->list[i], &storage->list[i].source_dset, dxpl_id) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")

                /* Check if source dataset is open */
                if(storage->list[i].source_dset.dset) {
                    /* Retrieve current source dataset extent and patch mapping
                     */
                    if(H5S_extent_copy(storage->list[i].source_select, storage->list[i].source_dset.dset->shared->space) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy source dataspace extent")

                    /* Get source space dimenstions */
                    if(H5S_get_simple_extent_dims(storage->list[i].source_select, source_dims, NULL) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get source space dimensions")

                    /* Get size that source selection would be clipped to to
                     * match size of virtual selection */
                    clip_size = H5S_hyper_get_clip_extent_match(storage->list[i].source_select, storage->list[i].source_dset.virtual_select, virtual_dims[storage->list[i].unlim_dim_virtual], FALSE);

                    /* Close previous clipped virtual selection, if any */
                    if(storage->list[i].source_dset.clipped_virtual_select) {
                        HDassert(storage->list[i].source_dset.clipped_virtual_select
                                != storage->list[i].source_dset.virtual_select);
                        if(H5S_close(storage->list[i].source_dset.clipped_virtual_select) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual dataspace")
                    } /* end if */

                    /* Copy virtual selection */
                    if(NULL == (storage->list[i].source_dset.clipped_virtual_select = H5S_copy(storage->list[i].source_dset.virtual_select, FALSE, TRUE)))
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")

                    /* Close previous clipped source selection, if any */
                    if(storage->list[i].source_dset.clipped_source_select) {
                        HDassert(storage->list[i].source_dset.clipped_source_select
                                != storage->list[i].source_select);
                        if(H5S_close(storage->list[i].source_dset.clipped_source_select) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source dataspace")
                    } /* end if */

                    /* Copy source selection */
                    if(NULL == (storage->list[i].source_dset.clipped_source_select = H5S_copy(storage->list[i].source_select, FALSE, TRUE)))
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy source selection")

                    /* Check if the clip size is within the current extent of
                     * the source dataset */
                    if(clip_size <= source_dims[storage->list[i].unlim_dim_source]) {
                        /* Clip virtual selection to extent */
                        if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_virtual_select, virtual_dims[storage->list[i].unlim_dim_virtual]))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")

                        /* Clip source selection to clip_size */
                        if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_source_select, clip_size))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")
                    } /* end if */
                    else {
                        /* Get size that virtual selection will be clipped to to
                         * match size of source selection within source extent
                         */
                        clip_size = H5S_hyper_get_clip_extent_match(storage->list[i].source_dset.virtual_select, storage->list[i].source_select, source_dims[storage->list[i].unlim_dim_source], FALSE);

                        /* Clip virtual selection to clip_size */
                        if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_virtual_select, clip_size))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")

                        /* Clip source selection to extent */
                        if(H5S_hyper_clip_unlim(storage->list[i].source_dset.clipped_source_select, source_dims[storage->list[i].unlim_dim_source]))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "failed to clip unlimited selection")
                    } /* end else */
                } /* end if */
                else {
                    HDassert(!storage->list[i].source_dset.clipped_virtual_select);
                    HDassert(!storage->list[i].source_dset.clipped_source_select);
                } /* end else */
            } /* end if */
            else {
                /* printf mapping */
                size_t sub_dset_max;
                hbool_t partial_block;

                /* Get number of sub-source datasets in current extent */
                sub_dset_max = (size_t)H5S_hyper_get_first_inc_block(storage->list[i].source_dset.virtual_select, virtual_dims[storage->list[i].unlim_dim_virtual], &partial_block);
                if(partial_block)
                    sub_dset_max++;

                /* Allocate or grow the sub_dset array if necessary */
                if(!storage->list[i].sub_dset) {
                    /* Allocate sub_dset array */
                    if(NULL == (storage->list[i].sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_calloc(sub_dset_max * sizeof(H5O_storage_virtual_srcdset_t))))
                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate sub dataset array")

                    /* Update sub_dset_nalloc */
                    storage->list[i].sub_dset_nalloc = sub_dset_max;
                } /* end if */
                else if(sub_dset_max > storage->list[i].sub_dset_nalloc) {
                    H5O_storage_virtual_srcdset_t *tmp_sub_dset;

                    /* Extend sub_dset array */
                    if(NULL == (tmp_sub_dset = (H5O_storage_virtual_srcdset_t *)H5MM_realloc(storage->list[i].sub_dset, sub_dset_max * sizeof(H5O_storage_virtual_srcdset_t))))
                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend sub dataset array")
                    storage->list[i].sub_dset = tmp_sub_dset;

                    /* Clear new space in sub_dset */
                    (void)HDmemset(&storage->list[i].sub_dset[storage->list[i].sub_dset_nalloc], 0, (sub_dset_max - storage->list[i].sub_dset_nalloc) * sizeof(H5O_storage_virtual_srcdset_t));

                    /* Update sub_dset_nalloc */
                    storage->list[i].sub_dset_nalloc = sub_dset_max;
                } /* end if */

                /* Iterate over sub dsets */
                for(j = 0; j < sub_dset_max; j++) {
                    /* Resolve file name */
                    if(!storage->list[i].sub_dset[j].file_name)
                        if(H5D__virtual_build_source_name(storage->list[i].source_file_name, storage->list[i].parsed_source_file_name, storage->list[i].psfn_static_strlen, storage->list[i].psfn_nsubs, j, &storage->list[i].sub_dset[j].file_name) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to build source file name")

                    /* Resolve dset name */
                    if(!storage->list[i].sub_dset[j].dset_name)
                        if(H5D__virtual_build_source_name(storage->list[i].source_dset_name, storage->list[i].parsed_source_dset_name, storage->list[i].psdn_static_strlen, storage->list[i].psdn_nsubs, j, &storage->list[i].sub_dset[j].dset_name) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to build source dataset name")

                    /* Resolve virtual selection for block */
                    if(!storage->list[i].sub_dset[j].virtual_select)
                        if(NULL == (storage->list[i].sub_dset[j].virtual_select = H5S_hyper_get_unlim_block(storage->list[i].source_dset.virtual_select, j)))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get block in unlimited selection")

                    /* Close previous clipped source selection, if any */
                    if(storage->list[i].sub_dset[j].clipped_source_select
                            != storage->list[i].source_select) {
                        if(storage->list[i].sub_dset[j].clipped_source_select)
                            if(H5S_close(storage->list[i].sub_dset[j].clipped_source_select) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped source dataspace")

                        /* Initialize clipped source selection to point to base
                         * source selection */
                        storage->list[i].sub_dset[j].clipped_source_select = storage->list[i].source_select;
                    } /* end if */

                    /* Close previous clipped virtual selection, if any */
                    if(storage->list[i].sub_dset[j].clipped_virtual_select
                            != storage->list[i].sub_dset[j].virtual_select) {
                        if(storage->list[i].sub_dset[j].clipped_virtual_select)
                            if(H5S_close(storage->list[i].sub_dset[j].clipped_virtual_select) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to release clipped virtual dataspace")

                        /* Initialize clipped virtual selection to point to
                         * unclipped virtual selection */
                        storage->list[i].sub_dset[j].clipped_virtual_select = storage->list[i].sub_dset[j].virtual_select;
                    } /* end if */

                    /* Clear clipped selections if this is a partial block,
                     * defer calculation of real clipped selections to
                     * H5D__virtual_pre_io() as we may not have a valid source
                     * extent here */
                    if((j == (sub_dset_max - 1)) && partial_block) {
                        /* Clear clipped source and virtual selections */
                        storage->list[i].sub_dset[j].clipped_source_select = NULL;
                        storage->list[i].sub_dset[j].clipped_virtual_select = NULL;
                    } /* end else */
                    /* Note we do not need to open the source file, this will
                     * happen later in H5D__virtual_pre_io() */
                } /* end for */

                /* Update sub_dset_nused */
                storage->list[i].sub_dset_nused = sub_dset_max;
            } /* end else */
        } /* end if */
        else {
            /* Limited mapping, just make sure the clipped selections were
             * already set.  Again, no need to open the source file. */
            HDassert(storage->list[i].source_dset.clipped_virtual_select);
            HDassert(storage->list[i].source_dset.clipped_source_select);
        } /* end else */

    /* Mark layout as fully initialized */
    storage->init = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_init_all() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_init
 *
 * Purpose:     Initialize the virtual layout information for a dataset.
 *              This is called when the dataset is initialized.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              Thursday, April 30, 2015
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5D__virtual_init(H5F_t *f, hid_t H5_ATTR_UNUSED dxpl_id, const H5D_t *dset,
    hid_t dapl_id)
{
    H5O_storage_virtual_t *storage;     /* Convenience pointer */
    H5P_genplist_t *dapl;               /* Data access property list object pointer */
    hssize_t old_offset[H5O_LAYOUT_NDIMS]; /* Old selection offset (unused) */
    size_t      i;                      /* Local index variables */
    herr_t      ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    HDassert(dset);
    storage = &dset->shared->layout.storage.u.virt;
    HDassert(storage->list || (storage->list_nused == 0));

    /* Check that the dimensions of the VDS are large enough */
    if(H5D_virtual_check_min_dims(dset) < 0)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "virtual dataset dimensions not large enough to contain all limited dimensions in all selections")

    /* Patch the virtual selection dataspaces.  Note we always patch the space
     * status because this layout could be from an old version held in the
     * object header message code.  We cannot update that held message because
     * the layout message is constant, so just overwrite the values here (and
     * invalidate other fields by setting storage->init to FALSE below).  Also
     * remove offset from selections.  We only have to update
     * source_space_status and virtual_space_status because others will be based
     * on these and should therefore already have been normalized. */
    for(i = 0; i < storage->list_nused; i++) {
        HDassert(storage->list[i].sub_dset_nalloc == 0);

        /* Patch extent */
        if(H5S_extent_copy(storage->list[i].source_dset.virtual_select, dset->shared->space) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy virtual dataspace extent")
        storage->list[i].virtual_space_status = H5O_VIRTUAL_STATUS_CORRECT;

        /* Mark source extent as invalid */
        storage->list[i].source_space_status = H5O_VIRTUAL_STATUS_INVALID;

        /* Normalize offsets, toss out old offset values */
        if(H5S_hyper_normalize_offset(storage->list[i].source_dset.virtual_select, old_offset) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_BADSELECT, FAIL, "unable to normalize dataspace by offset")
        if(H5S_hyper_normalize_offset(storage->list[i].source_select, old_offset) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_BADSELECT, FAIL, "unable to normalize dataspace by offset")
    } /* end for */

    /* Get dataset access property list */
    if(NULL == (dapl = (H5P_genplist_t *)H5I_object(dapl_id)))
        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for dapl ID")

    /* Get view option */
    if(H5P_get(dapl, H5D_ACS_VDS_VIEW_NAME, &storage->view) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get virtual view option")

    /* Get printf gap if view is H5D_VDS_LAST_AVAILABLE, otherwise set to 0 */
    if(storage->view == H5D_VDS_LAST_AVAILABLE) {
        if(H5P_get(dapl, H5D_ACS_VDS_PRINTF_GAP_NAME, &storage->printf_gap) < 0)
            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get virtual printf gap")
    } /* end if */
    else
        storage->printf_gap = (hsize_t)0;

    /* Retrieve VDS file FAPL to layout */
    if(storage->source_fapl <= 0)
        if((storage->source_fapl = H5F_get_access_plist(f, FALSE)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get fapl")

    /* Copy DAPL to layout */
    if(storage->source_dapl <= 0)
        if((storage->source_dapl = H5P_copy_plist(dapl, FALSE)) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy dapl")

    /* Mark layout as not fully initialized (must be done prior to I/O for
     * unlimited/printf selections) */
    storage->init = FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_init() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_is_space_alloc
 *
 * Purpose:     Query if space is allocated for layout
 *
 * Return:      TRUE if space is allocated
 *              FALSE if it is not
 *              Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
hbool_t
H5D__virtual_is_space_alloc(const H5O_storage_t H5_ATTR_UNUSED *storage)
{
    hbool_t ret_value;                  /* Return value */

    FUNC_ENTER_PACKAGE_NOERR

    /* Just return TRUE, since the global heap object containing the mappings is
     * created when the layout message is encoded, and nothing else needs to be
     * allocated for virtual datasets.  This also ensures that the library never
     * assumes (falsely) that no data is present in the dataset, causing errors.
     */
    ret_value = TRUE;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_is_space_alloc() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_pre_io
 *
 * Purpose:     Project all virtual mappings onto mem_space, with the
 *              results stored in projected_mem_space for each mapping.
 *              Opens all source datasets if possible.  The total number
 *              of elements is stored in tot_nelmts.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              June 3, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_pre_io(H5D_io_info_t *io_info,
    H5O_storage_virtual_t *storage, const H5S_t *file_space,
    const H5S_t *mem_space, hsize_t *tot_nelmts)
{
    hssize_t    select_nelmts;              /* Number of elements in selection */
    hsize_t     bounds_start[H5S_MAX_RANK]; /* Selection bounds start */
    hsize_t     bounds_end[H5S_MAX_RANK];   /* Selection bounds end */
    int         rank;
    hbool_t     bounds_init = FALSE;        /* Whether bounds_start, bounds_end, and rank are valid */
    size_t      i, j, k;                    /* Local index variables */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(storage);
    HDassert(mem_space);
    HDassert(file_space);
    HDassert(tot_nelmts);

    /* Initialize layout if necessary */
    if(!storage->init)
        if(H5D__virtual_init_all(io_info->dset, io_info->dxpl_id) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize virtual layout")

    /* Initialize tot_nelmts */
    *tot_nelmts = 0;

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nused; i++) {
        /* Sanity check that the virtual space has been patched by now */
        HDassert(storage->list[i].virtual_space_status == H5O_VIRTUAL_STATUS_CORRECT);

        /* Check for "printf" source dataset resolution */
        if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
            hbool_t partial_block;

            HDassert(storage->list[i].unlim_dim_virtual >= 0);

            /* Get selection bounds if necessary */
            if(!bounds_init) {
                /* Get rank of VDS */
                if((rank = H5S_GET_EXTENT_NDIMS(io_info->dset->shared->space)) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get number of dimensions")

                /* Get selection bounds */
                if(H5S_SELECT_BOUNDS(file_space, bounds_start, bounds_end) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")

                /* Adjust bounds_end to represent the extent just enclosing them
                 * (add 1) */
                for(j = 0; j < (size_t)rank; j++)
                    bounds_end[j]++;

                /* Bounds are now initialized */
                bounds_init = TRUE;
            } /* end if */

            /* Get index of first block in virtual selection */
            storage->list[i].sub_dset_io_start = (size_t)H5S_hyper_get_first_inc_block(storage->list[i].source_dset.virtual_select, bounds_start[storage->list[i].unlim_dim_virtual], NULL);

            /* Get index of first block outside of virtual selection */
            storage->list[i].sub_dset_io_end = (size_t)H5S_hyper_get_first_inc_block(storage->list[i].source_dset.virtual_select, bounds_end[storage->list[i].unlim_dim_virtual], &partial_block);
            if(partial_block)
                storage->list[i].sub_dset_io_end++;
            if(storage->list[i].sub_dset_io_end > storage->list[i].sub_dset_nused)
                storage->list[i].sub_dset_io_end = storage->list[i].sub_dset_nused;

            /* Iterate over sub-source dsets */
            for(j = storage->list[i].sub_dset_io_start;
                    j < storage->list[i].sub_dset_io_end; j++) {
                /* Check for clipped virtual selection */
                if(!storage->list[i].sub_dset[j].clipped_virtual_select) {
                    hsize_t start[H5S_MAX_RANK];
                    /* This should only be NULL if this is a partial block */
                    HDassert((j == (storage->list[i].sub_dset_io_end - 1))
                            && partial_block);

                    /* If the source space status is not correct, we must try to
                     * open the source dataset to patch it */
                    if(storage->list[i].source_space_status != H5O_VIRTUAL_STATUS_CORRECT) {
                        HDassert(!storage->list[i].sub_dset[j].dset);
                        if(H5D__virtual_open_source_dset(io_info->dset, &storage->list[i], &storage->list[i].sub_dset[j], io_info->dxpl_id) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")
                    } /* end if */

                    /* If we obtained a valid source space, we must create
                     * clipped source and virtual selections, otherwise we
                     * cannot do this and we will leave them NULL.  This doesn't
                     * hurt anything because we can't do I/O because the dataset
                     * must not have been found. */
                    if(storage->list[i].source_space_status == H5O_VIRTUAL_STATUS_CORRECT) {
                        hsize_t tmp_dims[H5S_MAX_RANK];
                        hsize_t vbounds_end[H5S_MAX_RANK];

                        /* Get bounds of virtual selection */
                        if(H5S_SELECT_BOUNDS(storage->list[i].sub_dset[j].virtual_select, tmp_dims, vbounds_end) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to get selection bounds")

                        HDassert(bounds_init);

                        /* Convert bounds to extent (add 1) */
                        for(k = 0; k < (size_t)rank; k++)
                            vbounds_end[k]++;

                        /* Temporarily set extent of virtual selection to bounds */
                        if(H5S_set_extent(storage->list[i].sub_dset[j].virtual_select, vbounds_end) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")

                        /* Get current VDS dimensions */
                        if(H5S_get_simple_extent_dims(io_info->dset->shared->space, tmp_dims, NULL) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get VDS dimensions")

                        /* Copy virtual selection */
                        if(NULL == (storage->list[i].sub_dset[j].clipped_virtual_select = H5S_copy(storage->list[i].sub_dset[j].virtual_select, FALSE, TRUE)))
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy virtual selection")

                        /* Clip virtual selection to real virtual extent */
                        (void)HDmemset(start, 0, sizeof(start));
                        if(H5S_select_hyperslab(storage->list[i].sub_dset[j].clipped_virtual_select, H5S_SELECT_AND, start, NULL, tmp_dims, NULL) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTSELECT, FAIL, "unable to clip hyperslab")

                        /* Project intersection of virtual space and clipped
                         * virtual space onto source space (create
                         * clipped_source_select) */
                        if(H5S_select_project_intersection(storage->list[i].sub_dset[j].virtual_select, storage->list[i].source_select, storage->list[i].sub_dset[j].clipped_virtual_select, &storage->list[i].sub_dset[j].clipped_source_select) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")

                        /* Set extents of virtual_select and
                         * clipped_virtual_select to virtual extent */
                        if(H5S_set_extent(storage->list[i].sub_dset[j].virtual_select, tmp_dims) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
                        if(H5S_set_extent(storage->list[i].sub_dset[j].clipped_virtual_select, tmp_dims) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space")
                    } /* end if */
                } /* end if */

                /* Only continue if we managed to obtain a
                 * clipped_virtual_select */
                if(storage->list[i].sub_dset[j].clipped_virtual_select) {
                    /* Project intersection of file space and mapping virtual space
                     * onto memory space */
                    if(H5S_select_project_intersection(file_space, mem_space, storage->list[i].sub_dset[j].clipped_virtual_select, &storage->list[i].sub_dset[j].projected_mem_space) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")

                    /* Check number of elements selected */
                    if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(storage->list[i].sub_dset[j].projected_mem_space)) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")

                    /* Check if anything is selected */
                    if(select_nelmts > (hssize_t)0) {
                        /* Open source dataset */
                        if(!storage->list[i].sub_dset[j].dset)
                            /* Try to open dataset */
                            if(H5D__virtual_open_source_dset(io_info->dset, &storage->list[i], &storage->list[i].sub_dset[j], io_info->dxpl_id) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")

                        /* If the source dataset is not open, mark the selected
                         * elements as zero so projected_mem_space is freed */
                        if(!storage->list[i].sub_dset[j].dset)
                            select_nelmts = (hssize_t)0;
                    } /* end if */

                    /* If there are not elements selected in this mapping, free
                     * projected_mem_space, otherwise update tot_nelmts */
                    if(select_nelmts == (hssize_t)0) {
                        if(H5S_close(storage->list[i].sub_dset[j].projected_mem_space) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
                        storage->list[i].sub_dset[j].projected_mem_space = NULL;
                    } /* end if */
                    else 
                        *tot_nelmts += (hsize_t)select_nelmts;
                } /* end if */
            } /* end for */
        } /* end if */
        else {
            if(storage->list[i].source_dset.clipped_virtual_select) {
                /* Project intersection of file space and mapping virtual space onto
                 * memory space */
                if(H5S_select_project_intersection(file_space, mem_space, storage->list[i].source_dset.clipped_virtual_select, &storage->list[i].source_dset.projected_mem_space) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")

                /* Check number of elements selected, add to tot_nelmts */
                if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(storage->list[i].source_dset.projected_mem_space)) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")

                /* Check if anything is selected */
                if(select_nelmts > (hssize_t)0) {
                    /* Open source dataset */
                    if(!storage->list[i].source_dset.dset) 
                        /* Try to open dataset */
                        if(H5D__virtual_open_source_dset(io_info->dset, &storage->list[i], &storage->list[i].source_dset, io_info->dxpl_id) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")

                    /* If the source dataset is not open, mark the selected elements
                     * as zero so projected_mem_space is freed */
                    if(!storage->list[i].source_dset.dset)
                        select_nelmts = (hssize_t)0;
                } /* end if */

                /* If there are not elements selected in this mapping, free
                 * projected_mem_space, otherwise update tot_nelmts */
                if(select_nelmts == (hssize_t)0) {
                    if(H5S_close(storage->list[i].source_dset.projected_mem_space) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
                    storage->list[i].source_dset.projected_mem_space = NULL;
                } /* end if */
                else
                    *tot_nelmts += (hsize_t)select_nelmts;
            } /* end if */
            else {
                /* If there is no clipped_dim_virtual, this must be an unlimited
                 * selection whose dataset was not found in the last call to
                 * H5Dget_space().  Do not attempt to open it as this might
                 * affect the extent and we are not going to recalculate it
                 * here. */
                HDassert(storage->list[i].unlim_dim_virtual >= 0);
                HDassert(!storage->list[i].source_dset.dset);
            } /* end else */
        } /* end else */
    } /* end for */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_pre_io() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_post_io
 *
 * Purpose:     Frees memory structures allocated by H5D__virtual_pre_io.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              June 4, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_post_io(H5O_storage_virtual_t *storage)
{
    size_t      i, j;                       /* Local index variables */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(storage);

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nused; i++)
        /* Check for "printf" source dataset resolution */
        if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
            /* Iterate over sub-source dsets */
            for(j = storage->list[i].sub_dset_io_start;
                    j < storage->list[i].sub_dset_io_end; j++)
                /* Close projected memory space */
                if(storage->list[i].sub_dset[j].projected_mem_space) {
                    if(H5S_close(storage->list[i].sub_dset[j].projected_mem_space) < 0)
                        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
                    storage->list[i].sub_dset[j].projected_mem_space = NULL;
                } /* end if */
        } /* end if */
        else
            /* Close projected memory space */
            if(storage->list[i].source_dset.projected_mem_space) {
                if(H5S_close(storage->list[i].source_dset.projected_mem_space) < 0)
                    HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
                storage->list[i].source_dset.projected_mem_space = NULL;
            } /* end if */

    /* Note the lack of a done: label.  This is because there are no HGOTO_ERROR
     * calls.  If one is added, a done: label must also be added */
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_post_io() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_read_one
 *
 * Purpose:     Read from a singe source dataset in a virtual dataset.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 15, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_read_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
    const H5S_t *file_space, H5O_storage_virtual_srcdset_t *source_dset)
{
    H5S_t       *projected_src_space = NULL; /* File space for selection in a single source dataset */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    HDassert(source_dset);

    /* Only perform I/O if there is a projected memory space, otherwise there
     * were no elements in the projection or the source dataset could not be
     * opened */
    if(source_dset->projected_mem_space) {
        HDassert(source_dset->dset);
        HDassert(source_dset->clipped_source_select);

        /* Project intersection of file space and mapping virtual space onto
         * mapping source space */
        if(H5S_select_project_intersection(source_dset->clipped_virtual_select, source_dset->clipped_source_select, file_space, &projected_src_space) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")

        /* Perform read on source dataset */
        if(H5D__read(source_dset->dset, type_info->dst_type_id, source_dset->projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.rbuf) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "can't read source dataset")

        /* Close projected_src_space */
        if(H5S_close(projected_src_space) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
        projected_src_space = NULL;
    } /* end if */

done:
    /* Release allocated resources on failure */
    if(projected_src_space) {
        HDassert(ret_value < 0);
        if(H5S_close(projected_src_space) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_read_one() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_read
 *
 * Purpose:     Read from a virtual dataset.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
    hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
    H5D_chunk_map_t H5_ATTR_UNUSED *fm)
{
    H5O_storage_virtual_t *storage;         /* Convenient pointer into layout struct */
    hsize_t     tot_nelmts;                 /* Total number of elements mapped to mem_space */
    H5S_t       *fill_space = NULL;         /* Space to fill with fill value */
    size_t      i, j;                       /* Local index variables */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(io_info);
    HDassert(io_info->u.rbuf);
    HDassert(type_info);
    HDassert(mem_space);
    HDassert(file_space);

    storage = &io_info->dset->shared->layout.storage.u.virt;
    HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));

#ifdef H5_HAVE_PARALLEL
    /* Parallel reads are not supported (yet) */
    if(H5F_HAS_FEATURE(io_info->dset->oloc.file, H5FD_FEAT_HAS_MPI))
        HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "parallel reads not supported on virtual datasets")
#endif /* H5_HAVE_PARALLEL */

    /* Prepare for I/O operation */
    if(H5D__virtual_pre_io(io_info, storage, file_space, mem_space, &tot_nelmts) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to prepare for I/O operation")

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nused; i++) {
        /* Sanity check that the virtual space has been patched by now */
        HDassert(storage->list[i].virtual_space_status == H5O_VIRTUAL_STATUS_CORRECT);

        /* Check for "printf" source dataset resolution */
        if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
            /* Iterate over sub-source dsets */
            for(j = storage->list[i].sub_dset_io_start;
                    j < storage->list[i].sub_dset_io_end; j++)
                if(H5D__virtual_read_one(io_info, type_info, file_space, &storage->list[i].sub_dset[j]) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to read source dataset")
        } /* end if */
        else
            /* Read from source dataset */
            if(H5D__virtual_read_one(io_info, type_info, file_space, &storage->list[i].source_dset) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to read source dataset")
    } /* end for */

    /* Fill unmapped part of buffer with fill value */
    if(tot_nelmts < nelmts) {
        H5D_fill_value_t fill_status;       /* Fill value status */

        /* Check the fill value status */
        if(H5P_is_fill_value_defined(&io_info->dset->shared->dcpl_cache.fill, &fill_status) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't tell if fill value defined")

        /* Always write fill value to memory buffer unless it is undefined */
        if(fill_status != H5D_FILL_VALUE_UNDEFINED) {
            /* Start with fill space equal to memory space */
            if(NULL == (fill_space = H5S_copy(mem_space, FALSE, TRUE)))
                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy memory selection")

            /* Iterate over mappings */
            for(i = 0; i < storage->list_nused; i++)
                /* Check for "printf" source dataset resolution */
                if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
                    /* Iterate over sub-source dsets */
                    for(j = storage->list[i].sub_dset_io_start;
                            j < storage->list[i].sub_dset_io_end; j++)
                        if(storage->list[i].sub_dset[j].projected_mem_space)
                            if(H5S_select_subtract(fill_space, storage->list[i].sub_dset[j].projected_mem_space) < 0)
                                HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to clip fill selection")
                } /* end if */
                else
                    if(storage->list[i].source_dset.projected_mem_space)
                        /* Subtract projected memory space from fill space */
                        if(H5S_select_subtract(fill_space, storage->list[i].source_dset.projected_mem_space) < 0)
                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to clip fill selection")

            /* Write fill values to memory buffer */
            if(H5D__fill(io_info->dset->shared->dcpl_cache.fill.buf, io_info->dset->shared->type, io_info->u.rbuf, type_info->mem_type, fill_space, io_info->dxpl_id) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "filling buf failed")

#ifndef NDEBUG
            /* Make sure the total number of elements written (including fill
             * values) >= nelmts */
            {
                hssize_t    select_nelmts;  /* Number of elements in selection */

                /* Get number of elements in fill dataspace */
                if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(fill_space)) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")

                /* Verify number of elements is correct.  Note that since we
                 * don't check for overlap we can't assert that these are equal
                 */
                HDassert((tot_nelmts + (hsize_t)select_nelmts) >= nelmts);
            } /* end block */
#endif /* NDEBUG */
        } /* end if */
    } /* end if */

done:
    /* Cleanup I/O operation */
    if(H5D__virtual_post_io(storage) < 0)
        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't cleanup I/O operation")

    /* Close fill space */
    if(fill_space)
        if(H5S_close(fill_space) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close fill space")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_read() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_write_one
 *
 * Purpose:     Write to a singe source dataset in a virtual dataset.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              May 15, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
    const H5S_t *file_space, H5O_storage_virtual_srcdset_t *source_dset)
{
    H5S_t       *projected_src_space = NULL; /* File space for selection in a single source dataset */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    HDassert(source_dset);

    /* Only perform I/O if there is a projected memory space, otherwise there
     * were no elements in the projection */
    if(source_dset->projected_mem_space) {
        HDassert(source_dset->dset);
        HDassert(source_dset->clipped_source_select);

        /* In the future we may wish to extent this implementation to extend
         * source datasets if a write to a virtual dataset goes past the current
         * extent in the unlimited dimension.  -NAF */
        /* Project intersection of file space and mapping virtual space onto
         * mapping source space */
        if(H5S_select_project_intersection(source_dset->virtual_select, source_dset->clipped_source_select, file_space, &projected_src_space) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")

        /* Perform write on source dataset */
        if(H5D__write(source_dset->dset, type_info->dst_type_id, source_dset->projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.wbuf) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "can't write to source dataset")

        /* Close projected_src_space */
        if(H5S_close(projected_src_space) < 0)
            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
        projected_src_space = NULL;
    } /* end if */

done:
    /* Release allocated resources on failure */
    if(projected_src_space) {
        HDassert(ret_value < 0);
        if(H5S_close(projected_src_space) < 0)
            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_write_one() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_write
 *
 * Purpose:     Write to a virtual dataset.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
    hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
    H5D_chunk_map_t H5_ATTR_UNUSED *fm)
{
    H5O_storage_virtual_t *storage;         /* Convenient pointer into layout struct */
    hsize_t     tot_nelmts;                 /* Total number of elements mapped to mem_space */
    size_t      i, j;                       /* Local index variables */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(io_info);
    HDassert(io_info->u.wbuf);
    HDassert(type_info);
    HDassert(mem_space);
    HDassert(file_space);

    storage = &io_info->dset->shared->layout.storage.u.virt;
    HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));

#ifdef H5_HAVE_PARALLEL
    /* Parallel writes are not supported (yet) */
    if(H5F_HAS_FEATURE(io_info->dset->oloc.file, H5FD_FEAT_HAS_MPI))
        HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "parallel writes not supported on virtual datasets")
#endif /* H5_HAVE_PARALLEL */

    /* Prepare for I/O operation */
    if(H5D__virtual_pre_io(io_info, storage, file_space, mem_space, &tot_nelmts) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to prepare for I/O operation")

    /* Fail if there are unmapped parts of the selection as they would not be
     * written */
    if(tot_nelmts != nelmts)
        HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "write requested to unmapped portion of virtual dataset")

    /* Iterate over mappings */
    for(i = 0; i < storage->list_nused; i++) {
        /* Sanity check that virtual space has been patched by now */
        HDassert(storage->list[i].virtual_space_status == H5O_VIRTUAL_STATUS_CORRECT);

        /* Check for "printf" source dataset resolution */
        if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
            /* Iterate over sub-source dsets */
            for(j = storage->list[i].sub_dset_io_start;
                    j < storage->list[i].sub_dset_io_end; j++)
                if(H5D__virtual_write_one(io_info, type_info, file_space, &storage->list[i].sub_dset[j]) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write to source dataset")
        } /* end if */
        else
            /* Write to source dataset */
            if(H5D__virtual_write_one(io_info, type_info, file_space, &storage->list[i].source_dset) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to write to source dataset")
    } /* end for */

done:
    /* Cleanup I/O operation */
    if(H5D__virtual_post_io(storage) < 0)
        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't cleanup I/O operation")

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_write() */


/*-------------------------------------------------------------------------
 * Function:    H5D__virtual_flush
 *
 * Purpose:     Writes all dirty data to disk.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Neil Fortner
 *              February 6, 2015
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5D__virtual_flush(H5D_t *dset, hid_t dxpl_id)
{
    H5O_storage_virtual_t *storage;         /* Convenient pointer into layout struct */
    size_t      i, j;                       /* Local index variables */
    herr_t      ret_value = SUCCEED;        /* Return value */

    FUNC_ENTER_STATIC

    /* Sanity check */
    HDassert(dset);

    storage = &dset->shared->layout.storage.u.virt;

    /* Flush only open datasets */
    for(i = 0; i < storage->list_nused; i++)
        /* Check for "printf" source dataset resolution */
        if(storage->list[i].psfn_nsubs || storage->list[i].psdn_nsubs) {
            /* Iterate over sub-source dsets */
            for(j = 0; j < storage->list[i].sub_dset_nused; j++)
                if(storage->list[i].sub_dset[j].dset)
                    /* Flush source dataset */
                    if(H5D__flush_real(storage->list[i].sub_dset[j].dset, dxpl_id) < 0)
                        HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to flush source dataset")
        } /* end if */
        else
            if(storage->list[i].source_dset.dset)
                /* Flush source dataset */
                if(H5D__flush_real(storage->list[i].source_dset.dset, dxpl_id) < 0)
                    HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to write to source dataset")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5D__virtual_flush() */