forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
fix_node.c
2821 lines (2434 loc) · 77.3 KB
/
fix_node.c
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
/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
#include <linux/time.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "reiserfs.h"
#include <linux/buffer_head.h>
/*
* To make any changes in the tree we find a node that contains item
* to be changed/deleted or position in the node we insert a new item
* to. We call this node S. To do balancing we need to decide what we
* will shift to left/right neighbor, or to a new node, where new item
* will be etc. To make this analysis simpler we build virtual
* node. Virtual node is an array of items, that will replace items of
* node S. (For instance if we are going to delete an item, virtual
* node does not contain it). Virtual node keeps information about
* item sizes and types, mergeability of first and last items, sizes
* of all entries in directory item. We use this array of items when
* calculating what we can shift to neighbors and how many nodes we
* have to have if we do not any shiftings, if we shift to left/right
* neighbor or to both.
*/
/*
* Takes item number in virtual node, returns number of item
* that it has in source buffer
*/
static inline int old_item_num(int new_num, int affected_item_num, int mode)
{
if (mode == M_PASTE || mode == M_CUT || new_num < affected_item_num)
return new_num;
if (mode == M_INSERT) {
RFALSE(new_num == 0,
"vs-8005: for INSERT mode and item number of inserted item");
return new_num - 1;
}
RFALSE(mode != M_DELETE,
"vs-8010: old_item_num: mode must be M_DELETE (mode = \'%c\'",
mode);
/* delete mode */
return new_num + 1;
}
static void create_virtual_node(struct tree_balance *tb, int h)
{
struct item_head *ih;
struct virtual_node *vn = tb->tb_vn;
int new_num;
struct buffer_head *Sh; /* this comes from tb->S[h] */
Sh = PATH_H_PBUFFER(tb->tb_path, h);
/* size of changed node */
vn->vn_size =
MAX_CHILD_SIZE(Sh) - B_FREE_SPACE(Sh) + tb->insert_size[h];
/* for internal nodes array if virtual items is not created */
if (h) {
vn->vn_nr_item = (vn->vn_size - DC_SIZE) / (DC_SIZE + KEY_SIZE);
return;
}
/* number of items in virtual node */
vn->vn_nr_item =
B_NR_ITEMS(Sh) + ((vn->vn_mode == M_INSERT) ? 1 : 0) -
((vn->vn_mode == M_DELETE) ? 1 : 0);
/* first virtual item */
vn->vn_vi = (struct virtual_item *)(tb->tb_vn + 1);
memset(vn->vn_vi, 0, vn->vn_nr_item * sizeof(struct virtual_item));
vn->vn_free_ptr += vn->vn_nr_item * sizeof(struct virtual_item);
/* first item in the node */
ih = item_head(Sh, 0);
/* define the mergeability for 0-th item (if it is not being deleted) */
if (op_is_left_mergeable(&ih->ih_key, Sh->b_size)
&& (vn->vn_mode != M_DELETE || vn->vn_affected_item_num))
vn->vn_vi[0].vi_type |= VI_TYPE_LEFT_MERGEABLE;
/*
* go through all items that remain in the virtual
* node (except for the new (inserted) one)
*/
for (new_num = 0; new_num < vn->vn_nr_item; new_num++) {
int j;
struct virtual_item *vi = vn->vn_vi + new_num;
int is_affected =
((new_num != vn->vn_affected_item_num) ? 0 : 1);
if (is_affected && vn->vn_mode == M_INSERT)
continue;
/* get item number in source node */
j = old_item_num(new_num, vn->vn_affected_item_num,
vn->vn_mode);
vi->vi_item_len += ih_item_len(ih + j) + IH_SIZE;
vi->vi_ih = ih + j;
vi->vi_item = ih_item_body(Sh, ih + j);
vi->vi_uarea = vn->vn_free_ptr;
/*
* FIXME: there is no check that item operation did not
* consume too much memory
*/
vn->vn_free_ptr +=
op_create_vi(vn, vi, is_affected, tb->insert_size[0]);
if (tb->vn_buf + tb->vn_buf_size < vn->vn_free_ptr)
reiserfs_panic(tb->tb_sb, "vs-8030",
"virtual node space consumed");
if (!is_affected)
/* this is not being changed */
continue;
if (vn->vn_mode == M_PASTE || vn->vn_mode == M_CUT) {
vn->vn_vi[new_num].vi_item_len += tb->insert_size[0];
/* pointer to data which is going to be pasted */
vi->vi_new_data = vn->vn_data;
}
}
/* virtual inserted item is not defined yet */
if (vn->vn_mode == M_INSERT) {
struct virtual_item *vi = vn->vn_vi + vn->vn_affected_item_num;
RFALSE(vn->vn_ins_ih == NULL,
"vs-8040: item header of inserted item is not specified");
vi->vi_item_len = tb->insert_size[0];
vi->vi_ih = vn->vn_ins_ih;
vi->vi_item = vn->vn_data;
vi->vi_uarea = vn->vn_free_ptr;
op_create_vi(vn, vi, 0 /*not pasted or cut */ ,
tb->insert_size[0]);
}
/*
* set right merge flag we take right delimiting key and
* check whether it is a mergeable item
*/
if (tb->CFR[0]) {
struct reiserfs_key *key;
key = internal_key(tb->CFR[0], tb->rkey[0]);
if (op_is_left_mergeable(key, Sh->b_size)
&& (vn->vn_mode != M_DELETE
|| vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1))
vn->vn_vi[vn->vn_nr_item - 1].vi_type |=
VI_TYPE_RIGHT_MERGEABLE;
#ifdef CONFIG_REISERFS_CHECK
if (op_is_left_mergeable(key, Sh->b_size) &&
!(vn->vn_mode != M_DELETE
|| vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) {
/*
* we delete last item and it could be merged
* with right neighbor's first item
*/
if (!
(B_NR_ITEMS(Sh) == 1
&& is_direntry_le_ih(item_head(Sh, 0))
&& ih_entry_count(item_head(Sh, 0)) == 1)) {
/*
* node contains more than 1 item, or item
* is not directory item, or this item
* contains more than 1 entry
*/
print_block(Sh, 0, -1, -1);
reiserfs_panic(tb->tb_sb, "vs-8045",
"rdkey %k, affected item==%d "
"(mode==%c) Must be %c",
key, vn->vn_affected_item_num,
vn->vn_mode, M_DELETE);
}
}
#endif
}
}
/*
* Using virtual node check, how many items can be
* shifted to left neighbor
*/
static void check_left(struct tree_balance *tb, int h, int cur_free)
{
int i;
struct virtual_node *vn = tb->tb_vn;
struct virtual_item *vi;
int d_size, ih_size;
RFALSE(cur_free < 0, "vs-8050: cur_free (%d) < 0", cur_free);
/* internal level */
if (h > 0) {
tb->lnum[h] = cur_free / (DC_SIZE + KEY_SIZE);
return;
}
/* leaf level */
if (!cur_free || !vn->vn_nr_item) {
/* no free space or nothing to move */
tb->lnum[h] = 0;
tb->lbytes = -1;
return;
}
RFALSE(!PATH_H_PPARENT(tb->tb_path, 0),
"vs-8055: parent does not exist or invalid");
vi = vn->vn_vi;
if ((unsigned int)cur_free >=
(vn->vn_size -
((vi->vi_type & VI_TYPE_LEFT_MERGEABLE) ? IH_SIZE : 0))) {
/* all contents of S[0] fits into L[0] */
RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE,
"vs-8055: invalid mode or balance condition failed");
tb->lnum[0] = vn->vn_nr_item;
tb->lbytes = -1;
return;
}
d_size = 0, ih_size = IH_SIZE;
/* first item may be merge with last item in left neighbor */
if (vi->vi_type & VI_TYPE_LEFT_MERGEABLE)
d_size = -((int)IH_SIZE), ih_size = 0;
tb->lnum[0] = 0;
for (i = 0; i < vn->vn_nr_item;
i++, ih_size = IH_SIZE, d_size = 0, vi++) {
d_size += vi->vi_item_len;
if (cur_free >= d_size) {
/* the item can be shifted entirely */
cur_free -= d_size;
tb->lnum[0]++;
continue;
}
/* the item cannot be shifted entirely, try to split it */
/*
* check whether L[0] can hold ih and at least one byte
* of the item body
*/
/* cannot shift even a part of the current item */
if (cur_free <= ih_size) {
tb->lbytes = -1;
return;
}
cur_free -= ih_size;
tb->lbytes = op_check_left(vi, cur_free, 0, 0);
if (tb->lbytes != -1)
/* count partially shifted item */
tb->lnum[0]++;
break;
}
return;
}
/*
* Using virtual node check, how many items can be
* shifted to right neighbor
*/
static void check_right(struct tree_balance *tb, int h, int cur_free)
{
int i;
struct virtual_node *vn = tb->tb_vn;
struct virtual_item *vi;
int d_size, ih_size;
RFALSE(cur_free < 0, "vs-8070: cur_free < 0");
/* internal level */
if (h > 0) {
tb->rnum[h] = cur_free / (DC_SIZE + KEY_SIZE);
return;
}
/* leaf level */
if (!cur_free || !vn->vn_nr_item) {
/* no free space */
tb->rnum[h] = 0;
tb->rbytes = -1;
return;
}
RFALSE(!PATH_H_PPARENT(tb->tb_path, 0),
"vs-8075: parent does not exist or invalid");
vi = vn->vn_vi + vn->vn_nr_item - 1;
if ((unsigned int)cur_free >=
(vn->vn_size -
((vi->vi_type & VI_TYPE_RIGHT_MERGEABLE) ? IH_SIZE : 0))) {
/* all contents of S[0] fits into R[0] */
RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE,
"vs-8080: invalid mode or balance condition failed");
tb->rnum[h] = vn->vn_nr_item;
tb->rbytes = -1;
return;
}
d_size = 0, ih_size = IH_SIZE;
/* last item may be merge with first item in right neighbor */
if (vi->vi_type & VI_TYPE_RIGHT_MERGEABLE)
d_size = -(int)IH_SIZE, ih_size = 0;
tb->rnum[0] = 0;
for (i = vn->vn_nr_item - 1; i >= 0;
i--, d_size = 0, ih_size = IH_SIZE, vi--) {
d_size += vi->vi_item_len;
if (cur_free >= d_size) {
/* the item can be shifted entirely */
cur_free -= d_size;
tb->rnum[0]++;
continue;
}
/*
* check whether R[0] can hold ih and at least one
* byte of the item body
*/
/* cannot shift even a part of the current item */
if (cur_free <= ih_size) {
tb->rbytes = -1;
return;
}
/*
* R[0] can hold the header of the item and at least
* one byte of its body
*/
cur_free -= ih_size; /* cur_free is still > 0 */
tb->rbytes = op_check_right(vi, cur_free);
if (tb->rbytes != -1)
/* count partially shifted item */
tb->rnum[0]++;
break;
}
return;
}
/*
* from - number of items, which are shifted to left neighbor entirely
* to - number of item, which are shifted to right neighbor entirely
* from_bytes - number of bytes of boundary item (or directory entries)
* which are shifted to left neighbor
* to_bytes - number of bytes of boundary item (or directory entries)
* which are shifted to right neighbor
*/
static int get_num_ver(int mode, struct tree_balance *tb, int h,
int from, int from_bytes,
int to, int to_bytes, short *snum012, int flow)
{
int i;
int units;
struct virtual_node *vn = tb->tb_vn;
int total_node_size, max_node_size, current_item_size;
int needed_nodes;
/* position of item we start filling node from */
int start_item;
/* position of item we finish filling node by */
int end_item;
/*
* number of first bytes (entries for directory) of start_item-th item
* we do not include into node that is being filled
*/
int start_bytes;
/*
* number of last bytes (entries for directory) of end_item-th item
* we do node include into node that is being filled
*/
int end_bytes;
/*
* these are positions in virtual item of items, that are split
* between S[0] and S1new and S1new and S2new
*/
int split_item_positions[2];
split_item_positions[0] = -1;
split_item_positions[1] = -1;
/*
* We only create additional nodes if we are in insert or paste mode
* or we are in replace mode at the internal level. If h is 0 and
* the mode is M_REPLACE then in fix_nodes we change the mode to
* paste or insert before we get here in the code.
*/
RFALSE(tb->insert_size[h] < 0 || (mode != M_INSERT && mode != M_PASTE),
"vs-8100: insert_size < 0 in overflow");
max_node_size = MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, h));
/*
* snum012 [0-2] - number of items, that lay
* to S[0], first new node and second new node
*/
snum012[3] = -1; /* s1bytes */
snum012[4] = -1; /* s2bytes */
/* internal level */
if (h > 0) {
i = ((to - from) * (KEY_SIZE + DC_SIZE) + DC_SIZE);
if (i == max_node_size)
return 1;
return (i / max_node_size + 1);
}
/* leaf level */
needed_nodes = 1;
total_node_size = 0;
/* start from 'from'-th item */
start_item = from;
/* skip its first 'start_bytes' units */
start_bytes = ((from_bytes != -1) ? from_bytes : 0);
/* last included item is the 'end_item'-th one */
end_item = vn->vn_nr_item - to - 1;
/* do not count last 'end_bytes' units of 'end_item'-th item */
end_bytes = (to_bytes != -1) ? to_bytes : 0;
/*
* go through all item beginning from the start_item-th item
* and ending by the end_item-th item. Do not count first
* 'start_bytes' units of 'start_item'-th item and last
* 'end_bytes' of 'end_item'-th item
*/
for (i = start_item; i <= end_item; i++) {
struct virtual_item *vi = vn->vn_vi + i;
int skip_from_end = ((i == end_item) ? end_bytes : 0);
RFALSE(needed_nodes > 3, "vs-8105: too many nodes are needed");
/* get size of current item */
current_item_size = vi->vi_item_len;
/*
* do not take in calculation head part (from_bytes)
* of from-th item
*/
current_item_size -=
op_part_size(vi, 0 /*from start */ , start_bytes);
/* do not take in calculation tail part of last item */
current_item_size -=
op_part_size(vi, 1 /*from end */ , skip_from_end);
/* if item fits into current node entierly */
if (total_node_size + current_item_size <= max_node_size) {
snum012[needed_nodes - 1]++;
total_node_size += current_item_size;
start_bytes = 0;
continue;
}
/*
* virtual item length is longer, than max size of item in
* a node. It is impossible for direct item
*/
if (current_item_size > max_node_size) {
RFALSE(is_direct_le_ih(vi->vi_ih),
"vs-8110: "
"direct item length is %d. It can not be longer than %d",
current_item_size, max_node_size);
/* we will try to split it */
flow = 1;
}
/* as we do not split items, take new node and continue */
if (!flow) {
needed_nodes++;
i--;
total_node_size = 0;
continue;
}
/*
* calculate number of item units which fit into node being
* filled
*/
{
int free_space;
free_space = max_node_size - total_node_size - IH_SIZE;
units =
op_check_left(vi, free_space, start_bytes,
skip_from_end);
/*
* nothing fits into current node, take new
* node and continue
*/
if (units == -1) {
needed_nodes++, i--, total_node_size = 0;
continue;
}
}
/* something fits into the current node */
start_bytes += units;
snum012[needed_nodes - 1 + 3] = units;
if (needed_nodes > 2)
reiserfs_warning(tb->tb_sb, "vs-8111",
"split_item_position is out of range");
snum012[needed_nodes - 1]++;
split_item_positions[needed_nodes - 1] = i;
needed_nodes++;
/* continue from the same item with start_bytes != -1 */
start_item = i;
i--;
total_node_size = 0;
}
/*
* sum012[4] (if it is not -1) contains number of units of which
* are to be in S1new, snum012[3] - to be in S0. They are supposed
* to be S1bytes and S2bytes correspondingly, so recalculate
*/
if (snum012[4] > 0) {
int split_item_num;
int bytes_to_r, bytes_to_l;
int bytes_to_S1new;
split_item_num = split_item_positions[1];
bytes_to_l =
((from == split_item_num
&& from_bytes != -1) ? from_bytes : 0);
bytes_to_r =
((end_item == split_item_num
&& end_bytes != -1) ? end_bytes : 0);
bytes_to_S1new =
((split_item_positions[0] ==
split_item_positions[1]) ? snum012[3] : 0);
/* s2bytes */
snum012[4] =
op_unit_num(&vn->vn_vi[split_item_num]) - snum012[4] -
bytes_to_r - bytes_to_l - bytes_to_S1new;
if (vn->vn_vi[split_item_num].vi_index != TYPE_DIRENTRY &&
vn->vn_vi[split_item_num].vi_index != TYPE_INDIRECT)
reiserfs_warning(tb->tb_sb, "vs-8115",
"not directory or indirect item");
}
/* now we know S2bytes, calculate S1bytes */
if (snum012[3] > 0) {
int split_item_num;
int bytes_to_r, bytes_to_l;
int bytes_to_S2new;
split_item_num = split_item_positions[0];
bytes_to_l =
((from == split_item_num
&& from_bytes != -1) ? from_bytes : 0);
bytes_to_r =
((end_item == split_item_num
&& end_bytes != -1) ? end_bytes : 0);
bytes_to_S2new =
((split_item_positions[0] == split_item_positions[1]
&& snum012[4] != -1) ? snum012[4] : 0);
/* s1bytes */
snum012[3] =
op_unit_num(&vn->vn_vi[split_item_num]) - snum012[3] -
bytes_to_r - bytes_to_l - bytes_to_S2new;
}
return needed_nodes;
}
/*
* Set parameters for balancing.
* Performs write of results of analysis of balancing into structure tb,
* where it will later be used by the functions that actually do the balancing.
* Parameters:
* tb tree_balance structure;
* h current level of the node;
* lnum number of items from S[h] that must be shifted to L[h];
* rnum number of items from S[h] that must be shifted to R[h];
* blk_num number of blocks that S[h] will be splitted into;
* s012 number of items that fall into splitted nodes.
* lbytes number of bytes which flow to the left neighbor from the
* item that is not shifted entirely
* rbytes number of bytes which flow to the right neighbor from the
* item that is not shifted entirely
* s1bytes number of bytes which flow to the first new node when
* S[0] splits (this number is contained in s012 array)
*/
static void set_parameters(struct tree_balance *tb, int h, int lnum,
int rnum, int blk_num, short *s012, int lb, int rb)
{
tb->lnum[h] = lnum;
tb->rnum[h] = rnum;
tb->blknum[h] = blk_num;
/* only for leaf level */
if (h == 0) {
if (s012 != NULL) {
tb->s0num = *s012++;
tb->snum[0] = *s012++;
tb->snum[1] = *s012++;
tb->sbytes[0] = *s012++;
tb->sbytes[1] = *s012;
}
tb->lbytes = lb;
tb->rbytes = rb;
}
PROC_INFO_ADD(tb->tb_sb, lnum[h], lnum);
PROC_INFO_ADD(tb->tb_sb, rnum[h], rnum);
PROC_INFO_ADD(tb->tb_sb, lbytes[h], lb);
PROC_INFO_ADD(tb->tb_sb, rbytes[h], rb);
}
/*
* check if node disappears if we shift tb->lnum[0] items to left
* neighbor and tb->rnum[0] to the right one.
*/
static int is_leaf_removable(struct tree_balance *tb)
{
struct virtual_node *vn = tb->tb_vn;
int to_left, to_right;
int size;
int remain_items;
/*
* number of items that will be shifted to left (right) neighbor
* entirely
*/
to_left = tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0);
to_right = tb->rnum[0] - ((tb->rbytes != -1) ? 1 : 0);
remain_items = vn->vn_nr_item;
/* how many items remain in S[0] after shiftings to neighbors */
remain_items -= (to_left + to_right);
/* all content of node can be shifted to neighbors */
if (remain_items < 1) {
set_parameters(tb, 0, to_left, vn->vn_nr_item - to_left, 0,
NULL, -1, -1);
return 1;
}
/* S[0] is not removable */
if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1)
return 0;
/* check whether we can divide 1 remaining item between neighbors */
/* get size of remaining item (in item units) */
size = op_unit_num(&vn->vn_vi[to_left]);
if (tb->lbytes + tb->rbytes >= size) {
set_parameters(tb, 0, to_left + 1, to_right + 1, 0, NULL,
tb->lbytes, -1);
return 1;
}
return 0;
}
/* check whether L, S, R can be joined in one node */
static int are_leaves_removable(struct tree_balance *tb, int lfree, int rfree)
{
struct virtual_node *vn = tb->tb_vn;
int ih_size;
struct buffer_head *S0;
S0 = PATH_H_PBUFFER(tb->tb_path, 0);
ih_size = 0;
if (vn->vn_nr_item) {
if (vn->vn_vi[0].vi_type & VI_TYPE_LEFT_MERGEABLE)
ih_size += IH_SIZE;
if (vn->vn_vi[vn->vn_nr_item - 1].
vi_type & VI_TYPE_RIGHT_MERGEABLE)
ih_size += IH_SIZE;
} else {
/* there was only one item and it will be deleted */
struct item_head *ih;
RFALSE(B_NR_ITEMS(S0) != 1,
"vs-8125: item number must be 1: it is %d",
B_NR_ITEMS(S0));
ih = item_head(S0, 0);
if (tb->CFR[0]
&& !comp_short_le_keys(&ih->ih_key,
internal_key(tb->CFR[0],
tb->rkey[0])))
/*
* Directory must be in correct state here: that is
* somewhere at the left side should exist first
* directory item. But the item being deleted can
* not be that first one because its right neighbor
* is item of the same directory. (But first item
* always gets deleted in last turn). So, neighbors
* of deleted item can be merged, so we can save
* ih_size
*/
if (is_direntry_le_ih(ih)) {
ih_size = IH_SIZE;
/*
* we might check that left neighbor exists
* and is of the same directory
*/
RFALSE(le_ih_k_offset(ih) == DOT_OFFSET,
"vs-8130: first directory item can not be removed until directory is not empty");
}
}
if (MAX_CHILD_SIZE(S0) + vn->vn_size <= rfree + lfree + ih_size) {
set_parameters(tb, 0, -1, -1, -1, NULL, -1, -1);
PROC_INFO_INC(tb->tb_sb, leaves_removable);
return 1;
}
return 0;
}
/* when we do not split item, lnum and rnum are numbers of entire items */
#define SET_PAR_SHIFT_LEFT \
if (h)\
{\
int to_l;\
\
to_l = (MAX_NR_KEY(Sh)+1 - lpar + vn->vn_nr_item + 1) / 2 -\
(MAX_NR_KEY(Sh) + 1 - lpar);\
\
set_parameters (tb, h, to_l, 0, lnver, NULL, -1, -1);\
}\
else \
{\
if (lset==LEFT_SHIFT_FLOW)\
set_parameters (tb, h, lpar, 0, lnver, snum012+lset,\
tb->lbytes, -1);\
else\
set_parameters (tb, h, lpar - (tb->lbytes!=-1), 0, lnver, snum012+lset,\
-1, -1);\
}
#define SET_PAR_SHIFT_RIGHT \
if (h)\
{\
int to_r;\
\
to_r = (MAX_NR_KEY(Sh)+1 - rpar + vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - rpar);\
\
set_parameters (tb, h, 0, to_r, rnver, NULL, -1, -1);\
}\
else \
{\
if (rset==RIGHT_SHIFT_FLOW)\
set_parameters (tb, h, 0, rpar, rnver, snum012+rset,\
-1, tb->rbytes);\
else\
set_parameters (tb, h, 0, rpar - (tb->rbytes!=-1), rnver, snum012+rset,\
-1, -1);\
}
static void free_buffers_in_tb(struct tree_balance *tb)
{
int i;
pathrelse(tb->tb_path);
for (i = 0; i < MAX_HEIGHT; i++) {
brelse(tb->L[i]);
brelse(tb->R[i]);
brelse(tb->FL[i]);
brelse(tb->FR[i]);
brelse(tb->CFL[i]);
brelse(tb->CFR[i]);
tb->L[i] = NULL;
tb->R[i] = NULL;
tb->FL[i] = NULL;
tb->FR[i] = NULL;
tb->CFL[i] = NULL;
tb->CFR[i] = NULL;
}
}
/*
* Get new buffers for storing new nodes that are created while balancing.
* Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked;
* CARRY_ON - schedule didn't occur while the function worked;
* NO_DISK_SPACE - no disk space.
*/
/* The function is NOT SCHEDULE-SAFE! */
static int get_empty_nodes(struct tree_balance *tb, int h)
{
struct buffer_head *new_bh, *Sh = PATH_H_PBUFFER(tb->tb_path, h);
b_blocknr_t *blocknr, blocknrs[MAX_AMOUNT_NEEDED] = { 0, };
int counter, number_of_freeblk;
int amount_needed; /* number of needed empty blocks */
int retval = CARRY_ON;
struct super_block *sb = tb->tb_sb;
/*
* number_of_freeblk is the number of empty blocks which have been
* acquired for use by the balancing algorithm minus the number of
* empty blocks used in the previous levels of the analysis,
* number_of_freeblk = tb->cur_blknum can be non-zero if a schedule
* occurs after empty blocks are acquired, and the balancing analysis
* is then restarted, amount_needed is the number needed by this
* level (h) of the balancing analysis.
*
* Note that for systems with many processes writing, it would be
* more layout optimal to calculate the total number needed by all
* levels and then to run reiserfs_new_blocks to get all of them at
* once.
*/
/*
* Initiate number_of_freeblk to the amount acquired prior to the
* restart of the analysis or 0 if not restarted, then subtract the
* amount needed by all of the levels of the tree below h.
*/
/* blknum includes S[h], so we subtract 1 in this calculation */
for (counter = 0, number_of_freeblk = tb->cur_blknum;
counter < h; counter++)
number_of_freeblk -=
(tb->blknum[counter]) ? (tb->blknum[counter] -
1) : 0;
/* Allocate missing empty blocks. */
/* if Sh == 0 then we are getting a new root */
amount_needed = (Sh) ? (tb->blknum[h] - 1) : 1;
/*
* Amount_needed = the amount that we need more than the
* amount that we have.
*/
if (amount_needed > number_of_freeblk)
amount_needed -= number_of_freeblk;
else /* If we have enough already then there is nothing to do. */
return CARRY_ON;
/*
* No need to check quota - is not allocated for blocks used
* for formatted nodes
*/
if (reiserfs_new_form_blocknrs(tb, blocknrs,
amount_needed) == NO_DISK_SPACE)
return NO_DISK_SPACE;
/* for each blocknumber we just got, get a buffer and stick it on FEB */
for (blocknr = blocknrs, counter = 0;
counter < amount_needed; blocknr++, counter++) {
RFALSE(!*blocknr,
"PAP-8135: reiserfs_new_blocknrs failed when got new blocks");
new_bh = sb_getblk(sb, *blocknr);
RFALSE(buffer_dirty(new_bh) ||
buffer_journaled(new_bh) ||
buffer_journal_dirty(new_bh),
"PAP-8140: journaled or dirty buffer %b for the new block",
new_bh);
/* Put empty buffers into the array. */
RFALSE(tb->FEB[tb->cur_blknum],
"PAP-8141: busy slot for new buffer");
set_buffer_journal_new(new_bh);
tb->FEB[tb->cur_blknum++] = new_bh;
}
if (retval == CARRY_ON && FILESYSTEM_CHANGED_TB(tb))
retval = REPEAT_SEARCH;
return retval;
}
/*
* Get free space of the left neighbor, which is stored in the parent
* node of the left neighbor.
*/
static int get_lfree(struct tree_balance *tb, int h)
{
struct buffer_head *l, *f;
int order;
if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL ||
(l = tb->FL[h]) == NULL)
return 0;
if (f == l)
order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) - 1;
else {
order = B_NR_ITEMS(l);
f = l;
}
return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order)));
}
/*
* Get free space of the right neighbor,
* which is stored in the parent node of the right neighbor.
*/
static int get_rfree(struct tree_balance *tb, int h)
{
struct buffer_head *r, *f;
int order;
if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL ||
(r = tb->FR[h]) == NULL)
return 0;
if (f == r)
order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) + 1;
else {
order = 0;
f = r;
}
return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order)));
}
/* Check whether left neighbor is in memory. */
static int is_left_neighbor_in_cache(struct tree_balance *tb, int h)
{
struct buffer_head *father, *left;
struct super_block *sb = tb->tb_sb;
b_blocknr_t left_neighbor_blocknr;
int left_neighbor_position;
/* Father of the left neighbor does not exist. */
if (!tb->FL[h])
return 0;
/* Calculate father of the node to be balanced. */
father = PATH_H_PBUFFER(tb->tb_path, h + 1);
RFALSE(!father ||
!B_IS_IN_TREE(father) ||
!B_IS_IN_TREE(tb->FL[h]) ||
!buffer_uptodate(father) ||
!buffer_uptodate(tb->FL[h]),
"vs-8165: F[h] (%b) or FL[h] (%b) is invalid",
father, tb->FL[h]);
/*
* Get position of the pointer to the left neighbor
* into the left father.
*/
left_neighbor_position = (father == tb->FL[h]) ?
tb->lkey[h] : B_NR_ITEMS(tb->FL[h]);
/* Get left neighbor block number. */
left_neighbor_blocknr =
B_N_CHILD_NUM(tb->FL[h], left_neighbor_position);
/* Look for the left neighbor in the cache. */
if ((left = sb_find_get_block(sb, left_neighbor_blocknr))) {
RFALSE(buffer_uptodate(left) && !B_IS_IN_TREE(left),
"vs-8170: left neighbor (%b %z) is not in the tree",
left, left);
put_bh(left);
return 1;
}
return 0;