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
|
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Copyright by The HDF Group. *
* Copyright by the Board of Trustees of the University of Illinois. *
* All rights reserved. *
* *
* This file is part of HDF5. The full HDF5 copyright notice, including *
* terms governing use, modification, and redistribution, is contained in *
* the COPYING file, which can be found at the root of the source code *
* distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases. *
* If you do not have access to either file, you may request a copy from *
* help@hdfgroup.org. *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*-------------------------------------------------------------------------
*
* Created: H5Defc.c
* December 13, 2010
* Neil Fortner <nfortne2@hdfgroup.org>
*
* Purpose: External file caching routines - implements a
* cache of external files to minimize the number of
* file opens and closes.
*
*-------------------------------------------------------------------------
*/
#define H5F_PACKAGE /*suppress error about including H5Fpkg */
/* Packages needed by this file... */
#include "H5private.h" /* Generic Functions */
#include "H5Eprivate.h" /* Error handling */
#include "H5Fpkg.h" /* File access */
#include "H5MMprivate.h" /* Memory management */
#include "H5Pprivate.h" /* Property lists */
/* Special values for the "tag" field below */
#define H5F_EFC_TAG_DEFAULT -1
#define H5F_EFC_TAG_LOCK -2
#define H5F_EFC_TAG_CLOSE -3
#define H5F_EFC_TAG_DONTCLOSE -4
/* Structure for each entry in a file's external file cache */
typedef struct H5F_efc_ent_t {
char *name; /* Name of the file */
H5F_t *file; /* File object */
struct H5F_efc_ent_t *LRU_next; /* Next item in LRU list */
struct H5F_efc_ent_t *LRU_prev; /* Previous item in LRU list */
unsigned nopen; /* Number of times this file is currently opened by an EFC client */
} H5F_efc_ent_t;
/* Structure for a shared file struct's external file cache */
struct H5F_efc_t {
H5SL_t *slist; /* Skip list of cached external files */
H5F_efc_ent_t *LRU_head; /* Head of LRU list. This is the least recently used file */
H5F_efc_ent_t *LRU_tail; /* Tail of LRU list. This is the most recently used file */
unsigned nfiles; /* Size of the external file cache */
unsigned max_nfiles; /* Maximum size of the external file cache */
unsigned nrefs; /* Number of times this file appears in another file's EFC */
int tag; /* Temporary variable used by H5F_efc_try_close() */
H5F_file_t *tmp_next; /* Next file in temporary list used by H5F_efc_try_close() */
};
/* Private prototypes */
static herr_t H5F_efc_remove_ent(H5F_efc_t *efc, H5F_efc_ent_t *ent);
static void H5F_efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail);
static void H5F_efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail);
/* Free lists */
H5FL_DEFINE_STATIC(H5F_efc_ent_t);
H5FL_DEFINE_STATIC(H5F_efc_t);
/*-------------------------------------------------------------------------
* Function: H5F_efc_create
*
* Purpose: Allocate and initialize a new external file cache object,
* which can the be used to cache open external files.
* the object must be freed with H5F_efc_destroy.
*
* Return: Pointer to new external file cache object on success
* NULL on failure
*
* Programmer: Neil Fortner
* Tuesday, December 14, 2010
*
*-------------------------------------------------------------------------
*/
H5F_efc_t *
H5F_efc_create(unsigned max_nfiles)
{
H5F_efc_t *efc = NULL; /* EFC object */
H5F_efc_t *ret_value; /* Return value */
FUNC_ENTER_NOAPI(NULL)
/* Sanity checks */
HDassert(max_nfiles > 0);
/* Allocate EFC struct */
if(NULL == (efc = H5FL_CALLOC(H5F_efc_t)))
HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
/* Initialize maximum number of files */
efc->max_nfiles = max_nfiles;
/* Initialize temporary ref count */
efc->tag = H5F_EFC_TAG_DEFAULT;
/* Set the return value */
ret_value = efc;
done:
if(ret_value == NULL && efc)
efc = H5FL_FREE(H5F_efc_t, efc);
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_efc_create() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_open
*
* Purpose: Opens a file using the external file cache. The target
* file is added to the external file cache of the parent
* if it is not already present. If the target file is in
* the parent's EFC, simply returns the target file. When
* the file object is no longer in use, it should be closed
* with H5F_efc_close (will not actually close the file
* until it is evicted from the EFC).
*
* Return: Pointer to open file on success
* NULL on failure
*
* Programmer: Neil Fortner
* Tuesday, December 14, 2010
*
*-------------------------------------------------------------------------
*/
H5F_t *
H5F_efc_open(H5F_t *parent, const char *name, unsigned flags, hid_t fcpl_id,
hid_t fapl_id, hid_t dxpl_id)
{
H5F_efc_t *efc = NULL; /* External file cache for parent file */
H5F_efc_ent_t *ent = NULL; /* Entry for target file in efc */
hbool_t open_file = FALSE; /* Whether ent->file needs to be closed in case of error */
H5F_t *ret_value = NULL; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(parent);
HDassert(parent->shared);
HDassert(name);
/* Get external file cache */
efc = parent->shared->efc;
/* Check if the EFC exists. If it does not, just call H5F_open(). We
* support this so clients do not have to make 2 different calls depending
* on the state of the efc. */
if(!efc) {
if(NULL == (ret_value = H5F_open(name, flags, fcpl_id, fapl_id,
dxpl_id)))
HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
/* Increment the number of open objects to prevent the file from being
* closed out from under us - "simulate" having an open file id. Note
* that this behaviour replaces the calls to H5F_incr_nopen_objs() and
* H5F_decr_nopen_objs() in H5L_extern_traverse(). */
ret_value->nopen_objs++;
HGOTO_DONE(ret_value)
} /* end if */
/* Search the skip list for name if the skip list exists, create the skip
* list otherwise */
if(efc->slist) {
if(efc->nfiles > 0)
ent = (H5F_efc_ent_t *)H5SL_search(efc->slist, name);
} /* end if */
else {
HDassert(efc->nfiles == 0);
if(NULL == (efc->slist = H5SL_create(H5SL_TYPE_STR, NULL)))
HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, NULL, "can't create skip list")
} /* end else */
/* If we found the file update the LRU list and return the cached file,
* otherwise open the file and cache it */
if(ent) {
HDassert(efc->LRU_head);
HDassert(efc->LRU_tail);
/* Move ent to the head of the LRU list, if it is not already there */
if(ent->LRU_prev) {
HDassert(efc->LRU_head != ent);
/* Remove from current position. Note that once we touch the LRU
* list we cannot revert to the previous state. Make sure there can
* be no errors between when we first touch the LRU list and when
* the cache is in a consistent state! */
if(ent->LRU_next)
ent->LRU_next->LRU_prev = ent->LRU_prev;
else {
HDassert(efc->LRU_tail == ent);
efc->LRU_tail = ent->LRU_prev;
} /* end else */
ent->LRU_prev->LRU_next = ent->LRU_next;
/* Add to head of LRU list */
ent->LRU_next = efc->LRU_head;
ent->LRU_next->LRU_prev = ent;
ent->LRU_prev = NULL;
efc->LRU_head = ent;
} /* end if */
/* Mark the file as open */
ent->nopen++;
} /* end if */
else {
/* Check if we need to evict something */
if(efc->nfiles == efc->max_nfiles) {
/* Search for an unopened file from the tail */
for(ent = efc->LRU_tail; ent && ent->nopen; ent = ent->LRU_prev);
/* Evict the file if found, otherwise just open the target file and
* do not add it to cache */
if(ent) {
if(H5F_efc_remove_ent(efc, ent) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTREMOVE, NULL, "can't remove entry from external file cache")
/* Do not free ent, we will recycle it below */
} /* end if */
else {
/* Cannot cache file, just open file and return */
if(NULL == (ret_value = H5F_open(name, flags, fcpl_id, fapl_id,
dxpl_id)))
HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
/* Increment the number of open objects to prevent the file from
* being closed out from under us - "simulate" having an open
* file id */
ret_value->nopen_objs++;
HGOTO_DONE(ret_value)
} /* end else */
} /* end if */
else
/* Allocate new entry */
if(NULL == (ent = H5FL_MALLOC(H5F_efc_ent_t)))
HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
/* Build new entry */
if(NULL == (ent->name = H5MM_strdup(name)))
HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
/* Open the file */
if(NULL == (ent->file = H5F_open(name, flags, fcpl_id, fapl_id,
dxpl_id)))
HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open file")
open_file = TRUE;
/* Increment the number of open objects to prevent the file from being
* closed out from under us - "simulate" having an open file id */
ent->file->nopen_objs++;
/* Add the file to the cache */
/* Skip list */
if(H5SL_insert(efc->slist, ent, ent->name) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTINSERT, NULL, "can't insert entry into skip list")
/* Add to head of LRU list and update tail if necessary */
ent->LRU_next = efc->LRU_head;
if(ent->LRU_next)
ent->LRU_next->LRU_prev = ent;
ent->LRU_prev = NULL;
efc->LRU_head = ent;
if(!efc->LRU_tail) {
HDassert(!ent->LRU_next);
efc->LRU_tail = ent;
} /* end if */
/* Mark the file as open */
ent->nopen = 1;
/* Update nfiles and nrefs */
efc->nfiles++;
if(ent->file->shared->efc)
ent->file->shared->efc->nrefs++;
} /* end else */
HDassert(ent);
HDassert(ent->file);
HDassert(ent->name);
HDassert(ent->nopen);
/* Set the return value */
ret_value = ent->file;
done:
if(!ret_value)
if(ent) {
if(open_file) {
ent->file->nopen_objs--;
if(H5F_try_close(ent->file) < 0)
HDONE_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, NULL, "can't close external file")
} /* end if */
ent->name = (char *)H5MM_xfree(ent->name);
ent = H5FL_FREE(H5F_efc_ent_t, ent);
} /* end if */
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_efc_open() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_close
*
* Purpose: Closes (unlocks) a file opened using the external file
* cache. The target file is not immediately closed unless
* there is no external file cache for the parent file.
*
* Return: Non-negative on success
* Negative on failure
*
* Programmer: Neil Fortner
* Wednesday, December 15, 2010
*
*-------------------------------------------------------------------------
*/
herr_t
H5F_efc_close(H5F_t *parent, H5F_t *file)
{
H5F_efc_t *efc = NULL; /* External file cache for parent file */
H5F_efc_ent_t *ent = NULL; /* Entry for target file in efc */
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(parent);
HDassert(parent->shared);
HDassert(file);
HDassert(file->shared);
/* Get external file cache */
efc = parent->shared->efc;
/* Check if the EFC exists. If it does not, just call H5F_try_close(). We
* support this so clients do not have to make 2 different calls depending
* on the state of the efc. */
if(!efc) {
file->nopen_objs--;
if(H5F_try_close(file) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
HGOTO_DONE(SUCCEED)
} /* end if */
/* Scan the parent's LRU list from the head to file file. We do this
* instead of a skip list lookup because the file will almost always be at
* the head. In the unlikely case that the file is not found, just call
* H5F_try_close(). This could happen if the EFC was full of open files
* when the file was opened. */
for(ent = efc->LRU_head; ent && ent->file != file; ent = ent->LRU_next);
if(!ent) {
file->nopen_objs--;
if(H5F_try_close(file) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
} /* end if */
else
/* Reduce the open count on this entry */
ent->nopen--;
done:
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_efc_close() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_max_nfiles
*
* Purpose: Returns the maximum number of files in the provided
* external file cache.
*
* Return: Maximum number of files (never fails)
*
* Programmer: Neil Fortner
* Wednesday, December 15, 2010
*
*-------------------------------------------------------------------------
*/
unsigned
H5F_efc_max_nfiles(H5F_efc_t *efc)
{
FUNC_ENTER_NOAPI_NOINIT_NOERR
HDassert(efc);
HDassert(efc->max_nfiles > 0);
FUNC_LEAVE_NOAPI(efc->max_nfiles)
} /* end H5F_efc_max_nfiles */
/*-------------------------------------------------------------------------
* Function: H5F_efc_release
*
* Purpose: Releases the external file cache, potentially closing any
* cached files unless they are held open from somewhere
* else (or are currently opened by a client).
*
* Return: Non-negative on success
* Negative on failure
*
* Programmer: Neil Fortner
* Wednesday, December 15, 2010
*
*-------------------------------------------------------------------------
*/
herr_t
H5F_efc_release(H5F_efc_t *efc)
{
H5F_efc_ent_t *ent = NULL; /* EFC entry */
H5F_efc_ent_t *prev_ent = NULL; /* Previous EFC entry */
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(efc);
/* Lock the EFC to prevent manipulation of the EFC wile we are releasing it.
* The EFC should never be locked when we enter this function because that
* would require a cycle, a cycle would necessarily invoke
* H5F_efc_try_close(), and that function checks the status of the lock
* before calling this one. */
HDassert((efc->tag == H5F_EFC_TAG_DEFAULT)
|| (efc->tag == H5F_EFC_TAG_CLOSE));
efc->tag = H5F_EFC_TAG_LOCK;
/* Walk down the LRU list, releasing any files that are not opened by an EFC
* client */
ent = efc->LRU_head;
while(ent)
if(!ent->nopen) {
if(H5F_efc_remove_ent(efc, ent) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTREMOVE, FAIL, "can't remove entry from external file cache")
/* Free the entry and move to next entry in LRU list */
prev_ent = ent;
ent = ent->LRU_next;
prev_ent = H5FL_FREE(H5F_efc_ent_t, prev_ent);
} /* end if */
else
/* Can't release file because it's open; just advance the pointer */
ent = ent->LRU_next;
/* Reset tag. No need to reset to CLOSE if that was the original tag, as in
* that case the file must be getting closed anyways. */
efc->tag = H5F_EFC_TAG_DEFAULT;
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5F_efc_release() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_destroy
*
* Purpose: Frees an external file cache object, releasing it first
* if necessary. If it cannot be fully released, for example
* if there are open files, returns an error.
*
* Return: Non-negative on success
* Negative on failure
*
* Programmer: Neil Fortner
* Wednesday, December 15, 2010
*
*-------------------------------------------------------------------------
*/
herr_t
H5F_efc_destroy(H5F_efc_t *efc)
{
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(efc);
if(efc->nfiles > 0) {
/* Release (clear) the efc */
if(H5F_efc_release(efc) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
/* If there are still cached files, return an error */
if(efc->nfiles > 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't destroy EFC after incomplete release")
} /* end if */
HDassert(efc->nfiles == 0);
HDassert(efc->LRU_head == NULL);
HDassert(efc->LRU_tail == NULL);
/* Close skip list */
if(efc->slist)
if(H5SL_close(efc->slist) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close skip list")
/* Free EFC object */
(void)H5FL_FREE(H5F_efc_t, efc);
done:
FUNC_LEAVE_NOAPI(ret_value);
} /* end H5F_efc_destroy() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_remove_ent
*
* Purpose: Removes the specified entry from the specified EFC,
* closing the file if requested. Does not free the entry.
*
* Return: Non-negative on success
* Negative on failure
*
* Programmer: Neil Fortner
* Wednesday, December 15, 2010
*
*-------------------------------------------------------------------------
*/
static herr_t
H5F_efc_remove_ent(H5F_efc_t *efc, H5F_efc_ent_t *ent)
{
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(efc);
HDassert(efc->slist);
HDassert(ent);
/* Remove from skip list */
if(ent != H5SL_remove(efc->slist, ent->name))
HGOTO_ERROR(H5E_FILE, H5E_CANTDELETE, FAIL, "can't delete entry from skip list")
/* Remove from LRU list */
if(ent->LRU_next)
ent->LRU_next->LRU_prev = ent->LRU_prev;
else {
HDassert(efc->LRU_tail == ent);
efc->LRU_tail = ent->LRU_prev;
} /* end else */
if(ent->LRU_prev)
ent->LRU_prev->LRU_next = ent->LRU_next;
else {
HDassert(efc->LRU_head == ent);
efc->LRU_head = ent->LRU_next;
} /* end else */
/* Update nfiles and nrefs */
efc->nfiles--;
if(ent->file->shared->efc)
ent->file->shared->efc->nrefs--;
/* Free the name */
ent->name = (char *)H5MM_xfree(ent->name);
/* Close the file. Note that since H5F_t structs returned from H5F_open()
* are *always* unique, there is no need to reference count this struct.
* However we must still manipulate the nopen_objs field to prevent the file
* from being closed out from under us. */
ent->file->nopen_objs--;
if(H5F_try_close(ent->file) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close external file")
ent->file = NULL;
done:
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_efc_remove_ent() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_try_close_tag1
*
* Purpose: Recursively traverse the EFC tree, keeping a temporary
* reference count on each file that assumes all reachable
* files will eventually be closed.
*
* Return: void (never fails)
*
* Programmer: Neil Fortner
* Monday, January 10, 2011
*
*-------------------------------------------------------------------------
*/
static void
H5F_efc_try_close_tag1(H5F_file_t *sf, H5F_file_t **tail)
{
H5F_efc_ent_t *ent = NULL; /* EFC entry */
H5F_file_t *esf; /* Convenience pointer to ent->file->shared */
FUNC_ENTER_NOAPI_NOINIT_NOERR
/* Sanity checks */
HDassert(sf);
HDassert(sf->efc);
HDassert((sf->efc->tag > 0) || (sf->nrefs == sf->efc->nrefs));
HDassert(sf->efc->tag != H5F_EFC_TAG_LOCK);
HDassert(tail);
HDassert(*tail);
/* Recurse into this file's cached files */
for(ent = sf->efc->LRU_head; ent; ent = ent->LRU_next) {
esf = ent->file->shared;
if(esf->efc) {
/* If tag were 0, that would mean there are more actual references
* than are counted by nrefs */
HDassert(esf->efc->tag != 0);
/* If tag has been set, we have already visited this file so just
* decrement tag and continue */
if(esf->efc->tag > 0)
esf->efc->tag--;
/* If there are references that are not from an EFC, it will never
* be possible to close the file. Just continue. Also continue if
* the EFC is locked or the file is open (through the EFC). Note
* that the reference counts will never match for the root file, but
* that's ok because the root file will always have a tag and enter
* the branch above. */
else if((esf->nrefs == esf->efc->nrefs)
&& (esf->efc->tag != H5F_EFC_TAG_LOCK) && !(ent->nopen)) {
/* If we get here, this file's "tmp_next" pointer must be NULL
*/
HDassert(esf->efc->tmp_next == NULL);
/* If nrefs > 1, Add this file to the list of files with nrefs >
* 1 and initialize tag to the number of references (except this
* one) */
if(esf->nrefs > 1) {
(*tail)->efc->tmp_next = esf;
*tail = esf;
esf->efc->tag = (int)esf->nrefs - 1;
} /* end if */
/* Recurse into the entry */
H5F_efc_try_close_tag1(ent->file->shared, tail);
} /* end if */
} /* end if */
} /* end for */
FUNC_LEAVE_NOAPI_VOID
} /* end H5F_efc_try_close_tag1() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_try_close_tag2
*
* Purpose: Recuresively mark all files reachable through this one as
* uncloseable, and add newly uncloseable files to the tail
* of the provided linked list.
*
* Return: void (never fails)
*
* Programmer: Neil Fortner
* Monday, January 10, 2011
*
*-------------------------------------------------------------------------
*/
static void
H5F_efc_try_close_tag2(H5F_file_t *sf, H5F_file_t **tail)
{
H5F_efc_ent_t *ent = NULL; /* EFC entry */
H5F_file_t *esf; /* Convenience pointer to ent->file->shared */
FUNC_ENTER_NOAPI_NOINIT_NOERR
/* Sanity checks */
HDassert(sf);
HDassert(sf->efc);
/* Recurse into this file's cached files */
for(ent = sf->efc->LRU_head; ent; ent = ent->LRU_next) {
esf = ent->file->shared;
/* Only recurse if the file is tagged CLOSE or DEFAULT. If it is tagged
* DONTCLOSE, we have already visited this file *or* it will be the
* start point of another iteration. No files should be tagged with a
* nonegative value at this point. If it is tagged as DEFAULT, we must
* apply the same conditions as in cb1 above for recursion in order to
* make sure we do not go off into somewhere cb1 didn't touch. The
* root file should never be tagged DEFAULT here, so the reference check
* is still appropriate. */
if((esf->efc) && ((esf->efc->tag == H5F_EFC_TAG_CLOSE)
|| ((esf->efc->tag == H5F_EFC_TAG_DEFAULT)
&& (esf->nrefs == esf->efc->nrefs) && !(ent->nopen)))) {
/* tag should always be CLOSE is nrefs > 1 or DEFAULT if nrefs == 1
* here */
HDassert(((esf->nrefs > 1)
&& ((esf->efc->tag == H5F_EFC_TAG_CLOSE)))
|| ((esf->nrefs == 1)
&& (esf->efc->tag == H5F_EFC_TAG_DEFAULT)));
/* If tag is set to DONTCLOSE, we have already visited this file
* *or* it will be the start point of another iteration so just
* continue */
if(esf->efc->tag != H5F_EFC_TAG_DONTCLOSE) {
/* If tag is CLOSE, set to DONTCLOSE and add to the list of
* uncloseable files. */
if(esf->efc->tag == H5F_EFC_TAG_CLOSE) {
esf->efc->tag = H5F_EFC_TAG_DONTCLOSE;
esf->efc->tmp_next = NULL;
(*tail)->efc->tmp_next = esf;
*tail = esf;
} /* end if */
/* Recurse into the entry */
H5F_efc_try_close_tag2(esf, tail);
} /* end if */
} /* end if */
} /* end for */
FUNC_LEAVE_NOAPI_VOID
} /* end H5F_efc_try_close_tag2() */
/*-------------------------------------------------------------------------
* Function: H5F_efc_try_close
*
* Purpose: Attempts to close the provided (shared) file by checking
* to see if the releasing the EFC would cause its reference
* count to drop to 0. Necessary to handle the case where
* chained EFCs form a cycle. Note that this function does
* not actually close the file (though it closes all children
* as appropriate), as that is left up to the calling
* function H5F_try_close().
*
* Because H5F_try_close() has no way of telling if it is
* called recursively from within this function, this
* function serves as both the root of iteration and the
* "callback" for the final pass (the one where the files are
* actually closed). The code for the callback case is at
* the top of this function; luckily it only consists of a
* (possible) call to H5F_efc_release().
*
* The algorithm basically consists of 3 passes over the EFC
* tree. The first pass assumes that every reachable file is
* closed, and keeps track of what the final reference count
* would be for every reachable file. The files are then
* tagged as either closeable or uncloseable based on whether
* this reference count drops to 0.
*
* The second pass initiates a traversal from each file
* marked as uncloseable in the first pass, and marks every
* file reachable from the initial uncloseable file as
* uncloseable. This eliminates files that were marked as
* closeable only because the first pass assumed that an
* uncloseable file would be closed.
*
* The final pass exploits the H5F_efc_release()->
* H5F_efc_remove_ent()->H5F_try_close()->H5F_efc_try_close()
* calling chain to recursively close the tree, but only the
* files that are still marked as closeable. All files
* marked as closeable have their EFCs released, and will
* eventually be closed when their last parent EFC is
* released (the last part is guaranteed to be true by the
* first 2 passes).
*
* Return: Non-negative on success
* Negative on failure
*
* Programmer: Neil Fortner
* Thursday, January 6, 2011
*
*-------------------------------------------------------------------------
*/
herr_t
H5F_efc_try_close(H5F_t *f)
{
H5F_file_t *tail; /* Tail of linked list of found files. Head will be f->shared. */
H5F_file_t *uncloseable_head = NULL; /* Head of linked list of files found to be uncloseable by the first pass */
H5F_file_t *uncloseable_tail = NULL; /* Tail of linked list of files found to be uncloseable by the first pass */
H5F_file_t *sf; /* Temporary file pointer */
H5F_file_t *next; /* Temporary file pointer */
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_NOAPI_NOINIT
/* Sanity checks */
HDassert(f);
HDassert(f->shared);
HDassert(f->shared->efc);
HDassert(f->shared->nrefs > f->shared->efc->nrefs);
HDassert(f->shared->nrefs > 1);
HDassert(f->shared->efc->tag < 0);
if(f->shared->efc->tag == H5F_EFC_TAG_CLOSE) {
/* We must have reentered this function, and we should close this file.
* In actuality, we just release the EFC, the recursion should
* eventually reduce this file's reference count to 1 (though possibly
* not from this call to H5F_efc_release()). */
if(H5F_efc_release(f->shared->efc) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
/* If we marked the file as closeable, there must be no open files in
* its EFC. This is because, in order to close an open child file, the
* client must keep a copy of the parent file open. The algorithm
* detect that the parent file is open (directly or through an EFC) and
* refuse to close it. Verify that all files were released from this
* EFC (i.e. none were open). */
HDassert(f->shared->efc->nfiles == 0);
HGOTO_DONE(SUCCEED)
} /* end if */
/* Conditions where we should not do anything and just return immediately */
/* If there are references that are not from an EFC or f, it will never
* be possible to close the file. Just return. Note that this holds true
* for the case that this file is being closed through H5F_efc_release()
* because that function (through H5F_efc_remove_ent()) decrements the EFC
* reference count before it calls H5F_try_close(). This may occur if this
* function is reentered. */
/* If the tag is H5F_EFC_TAG_DONTCLOSE, then we have definitely reentered
* this function, and this file has been marked as uncloseable, so we should
* not close/release it */
/* If nfiles is 0, then there is nothing to do. Just return. This may also
* occur on reentry (for example if this file was previously released). */
if((f->shared->nrefs != f->shared->efc->nrefs + 1)
|| (f->shared->efc->tag == H5F_EFC_TAG_DONTCLOSE)
|| (f->shared->efc->nfiles == 0))
/* We must have reentered this function, and we should not close this
* file. Just return. */
HGOTO_DONE(SUCCEED)
/* If the file EFC were locked, that should always mean that there exists
* a reference to this file that is not in an EFC (it may have just been
* removed from an EFC), and should have been caught by the above check */
/* If we get here then we must be beginning a new run. Make sure that the
* temporary variables in f->shared->efc are at the default value */
HDassert(f->shared->efc->tag == H5F_EFC_TAG_DEFAULT);
HDassert(f->shared->efc->tmp_next == NULL);
/* Set up linked list for traversal into EFC tree. f->shared is guaranteed
* to always be at the head. */
tail = f->shared;
/* Set up temporary reference count on root file */
f->shared->efc->tag = (int)f->shared->efc->nrefs;
/* First Pass: simulate closing all files reachable from this one, use "tag"
* field to keep track of final reference count for each file (including
* this one). Keep list of files with starting reference count > 1 (head is
* f->shared). */
H5F_efc_try_close_tag1(f->shared, &tail);
/* Check if f->shared->efc->tag dropped to 0. If it did not,
* we cannot close anything. Just reset temporary values and return. */
if(f->shared->efc->tag > 0) {
sf = f->shared;
while(sf) {
next = sf->efc->tmp_next;
sf->efc->tag = H5F_EFC_TAG_DEFAULT;
sf->efc->tmp_next = NULL;
sf = next;
} /* end while */
HGOTO_DONE(SUCCEED)
} /* end if */
/* Run through the linked list , separating into two lists, one with tag ==
* 0 and one with tag > 0. Mark them as either H5F_EFC_TAG_CLOSE or
* H5F_EFC_TAG_DONTCLOSE as appropriate. */
sf = f->shared;
tail = NULL;
while(sf) {
HDassert(sf->efc->tag >= 0);
next = sf->efc->tmp_next;
if(sf->efc->tag > 0) {
/* Remove from main list */
HDassert(tail);
tail->efc->tmp_next = sf->efc->tmp_next;
sf->efc->tmp_next = NULL;
/* Add to uncloseable list */
if(!uncloseable_head)
uncloseable_head = sf;
else
uncloseable_tail->efc->tmp_next = sf;
uncloseable_tail = sf;
/* Mark as uncloseable */
sf->efc->tag = H5F_EFC_TAG_DONTCLOSE;
} /* end if */
else {
sf->efc->tag = H5F_EFC_TAG_CLOSE;
tail = sf;
} /* end else */
sf = next;
} /* end while */
/* Second pass: Determine which of the reachable files found in pass 1
* cannot be closed by releasing the root file's EFC. Run through the
* uncloseable list, for each item traverse the files reachable through the
* EFC, mark the file as uncloseable, and add it to the list of uncloseable
* files (for cleanup). Use "tail" to store the original uncloseable tail
* so we know when to stop. We do not need to keep track of the closeable
* list any more. */
sf = uncloseable_head;
if(sf) {
tail = uncloseable_tail;
HDassert(tail);
while(sf != tail->efc->tmp_next) {
H5F_efc_try_close_tag2(sf, &uncloseable_tail);
sf = sf->efc->tmp_next;
} /* end while */
} /* end if */
/* If the root file's tag is still H5F_EFC_TAG_CLOSE, release its EFC. This
* should start the recursive release that should close all closeable files.
* Also, see the top of this function. */
if(f->shared->efc->tag == H5F_EFC_TAG_CLOSE) {
if(H5F_efc_release(f->shared->efc) < 0)
HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "can't release external file cache")
/* Make sure the file's reference count is now 1 and will be closed by
* H5F_dest(). */
HDassert(f->shared->nrefs == 1);
} /* end if */
/* Clean up uncloseable files (reset tag and tmp_next). All closeable files
* should have been closed, and therefore do not need to be cleaned up. */
if(uncloseable_head) {
sf = uncloseable_head;
while(sf) {
next = sf->efc->tmp_next;
HDassert(sf->efc->tag == H5F_EFC_TAG_DONTCLOSE);
sf->efc->tag = H5F_EFC_TAG_DEFAULT;
sf->efc->tmp_next = NULL;
sf = next;
} /* end while */
} /* end if */
done:
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_efc_try_close() */
|