summaryrefslogtreecommitdiff
path: root/fs/reiserfs/ibalance.c
blob: de391a82b9999830cb8eb89b3633b960ac96e2e8 (plain) (blame)
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
/*
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

#include <asm/uaccess.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/reiserfs_fs.h>
#include <linux/buffer_head.h>

/* this is one and only function that is used outside (do_balance.c) */
int balance_internal(struct tree_balance *,
		     int, int, struct item_head *, struct buffer_head **);

/* modes of internal_shift_left, internal_shift_right and internal_insert_childs */
#define INTERNAL_SHIFT_FROM_S_TO_L 0
#define INTERNAL_SHIFT_FROM_R_TO_S 1
#define INTERNAL_SHIFT_FROM_L_TO_S 2
#define INTERNAL_SHIFT_FROM_S_TO_R 3
#define INTERNAL_INSERT_TO_S 4
#define INTERNAL_INSERT_TO_L 5
#define INTERNAL_INSERT_TO_R 6

static void internal_define_dest_src_infos(int shift_mode,
					   struct tree_balance *tb,
					   int h,
					   struct buffer_info *dest_bi,
					   struct buffer_info *src_bi,
					   int *d_key, struct buffer_head **cf)
{
	memset(dest_bi, 0, sizeof(struct buffer_info));
	memset(src_bi, 0, sizeof(struct buffer_info));
	/* define dest, src, dest parent, dest position */
	switch (shift_mode) {
	case INTERNAL_SHIFT_FROM_S_TO_L:	/* used in internal_shift_left */
		src_bi->tb = tb;
		src_bi->bi_bh = PATH_H_PBUFFER(tb->tb_path, h);
		src_bi->bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		src_bi->bi_position = PATH_H_POSITION(tb->tb_path, h + 1);
		dest_bi->tb = tb;
		dest_bi->bi_bh = tb->L[h];
		dest_bi->bi_parent = tb->FL[h];
		dest_bi->bi_position = get_left_neighbor_position(tb, h);
		*d_key = tb->lkey[h];
		*cf = tb->CFL[h];
		break;
	case INTERNAL_SHIFT_FROM_L_TO_S:
		src_bi->tb = tb;
		src_bi->bi_bh = tb->L[h];
		src_bi->bi_parent = tb->FL[h];
		src_bi->bi_position = get_left_neighbor_position(tb, h);
		dest_bi->tb = tb;
		dest_bi->bi_bh = PATH_H_PBUFFER(tb->tb_path, h);
		dest_bi->bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		dest_bi->bi_position = PATH_H_POSITION(tb->tb_path, h + 1);	/* dest position is analog of dest->b_item_order */
		*d_key = tb->lkey[h];
		*cf = tb->CFL[h];
		break;

	case INTERNAL_SHIFT_FROM_R_TO_S:	/* used in internal_shift_left */
		src_bi->tb = tb;
		src_bi->bi_bh = tb->R[h];
		src_bi->bi_parent = tb->FR[h];
		src_bi->bi_position = get_right_neighbor_position(tb, h);
		dest_bi->tb = tb;
		dest_bi->bi_bh = PATH_H_PBUFFER(tb->tb_path, h);
		dest_bi->bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		dest_bi->bi_position = PATH_H_POSITION(tb->tb_path, h + 1);
		*d_key = tb->rkey[h];
		*cf = tb->CFR[h];
		break;

	case INTERNAL_SHIFT_FROM_S_TO_R:
		src_bi->tb = tb;
		src_bi->bi_bh = PATH_H_PBUFFER(tb->tb_path, h);
		src_bi->bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		src_bi->bi_position = PATH_H_POSITION(tb->tb_path, h + 1);
		dest_bi->tb = tb;
		dest_bi->bi_bh = tb->R[h];
		dest_bi->bi_parent = tb->FR[h];
		dest_bi->bi_position = get_right_neighbor_position(tb, h);
		*d_key = tb->rkey[h];
		*cf = tb->CFR[h];
		break;

	case INTERNAL_INSERT_TO_L:
		dest_bi->tb = tb;
		dest_bi->bi_bh = tb->L[h];
		dest_bi->bi_parent = tb->FL[h];
		dest_bi->bi_position = get_left_neighbor_position(tb, h);
		break;

	case INTERNAL_INSERT_TO_S:
		dest_bi->tb = tb;
		dest_bi->bi_bh = PATH_H_PBUFFER(tb->tb_path, h);
		dest_bi->bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		dest_bi->bi_position = PATH_H_POSITION(tb->tb_path, h + 1);
		break;

	case INTERNAL_INSERT_TO_R:
		dest_bi->tb = tb;
		dest_bi->bi_bh = tb->R[h];
		dest_bi->bi_parent = tb->FR[h];
		dest_bi->bi_position = get_right_neighbor_position(tb, h);
		break;

	default:
		reiserfs_panic(tb->tb_sb,
			       "internal_define_dest_src_infos: shift type is unknown (%d)",
			       shift_mode);
	}
}

/* Insert count node pointers into buffer cur before position to + 1.
 * Insert count items into buffer cur before position to.
 * Items and node pointers are specified by inserted and bh respectively.
 */
static void internal_insert_childs(struct buffer_info *cur_bi,
				   int to, int count,
				   struct item_head *inserted,
				   struct buffer_head **bh)
{
	struct buffer_head *cur = cur_bi->bi_bh;
	struct block_head *blkh;
	int nr;
	struct reiserfs_key *ih;
	struct disk_child new_dc[2];
	struct disk_child *dc;
	int i;

	if (count <= 0)
		return;

	blkh = B_BLK_HEAD(cur);
	nr = blkh_nr_item(blkh);

	RFALSE(count > 2, "too many children (%d) are to be inserted", count);
	RFALSE(B_FREE_SPACE(cur) < count * (KEY_SIZE + DC_SIZE),
	       "no enough free space (%d), needed %d bytes",
	       B_FREE_SPACE(cur), count * (KEY_SIZE + DC_SIZE));

	/* prepare space for count disk_child */
	dc = B_N_CHILD(cur, to + 1);

	memmove(dc + count, dc, (nr + 1 - (to + 1)) * DC_SIZE);

	/* copy to_be_insert disk children */
	for (i = 0; i < count; i++) {
		put_dc_size(&(new_dc[i]),
			    MAX_CHILD_SIZE(bh[i]) - B_FREE_SPACE(bh[i]));
		put_dc_block_number(&(new_dc[i]), bh[i]->b_blocknr);
	}
	memcpy(dc, new_dc, DC_SIZE * count);

	/* prepare space for count items  */
	ih = B_N_PDELIM_KEY(cur, ((to == -1) ? 0 : to));

	memmove(ih + count, ih,
		(nr - to) * KEY_SIZE + (nr + 1 + count) * DC_SIZE);

	/* copy item headers (keys) */
	memcpy(ih, inserted, KEY_SIZE);
	if (count > 1)
		memcpy(ih + 1, inserted + 1, KEY_SIZE);

	/* sizes, item number */
	set_blkh_nr_item(blkh, blkh_nr_item(blkh) + count);
	set_blkh_free_space(blkh,
			    blkh_free_space(blkh) - count * (DC_SIZE +
							     KEY_SIZE));

	do_balance_mark_internal_dirty(cur_bi->tb, cur, 0);

	/*&&&&&&&&&&&&&&&&&&&&&&&& */
	check_internal(cur);
	/*&&&&&&&&&&&&&&&&&&&&&&&& */

	if (cur_bi->bi_parent) {
		struct disk_child *t_dc =
		    B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
		put_dc_size(t_dc,
			    dc_size(t_dc) + (count * (DC_SIZE + KEY_SIZE)));
		do_balance_mark_internal_dirty(cur_bi->tb, cur_bi->bi_parent,
					       0);

		/*&&&&&&&&&&&&&&&&&&&&&&&& */
		check_internal(cur_bi->bi_parent);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */
	}

}

/* Delete del_num items and node pointers from buffer cur starting from *
 * the first_i'th item and first_p'th pointers respectively.		*/
static void internal_delete_pointers_items(struct buffer_info *cur_bi,
					   int first_p,
					   int first_i, int del_num)
{
	struct buffer_head *cur = cur_bi->bi_bh;
	int nr;
	struct block_head *blkh;
	struct reiserfs_key *key;
	struct disk_child *dc;

	RFALSE(cur == NULL, "buffer is 0");
	RFALSE(del_num < 0,
	       "negative number of items (%d) can not be deleted", del_num);
	RFALSE(first_p < 0 || first_p + del_num > B_NR_ITEMS(cur) + 1
	       || first_i < 0,
	       "first pointer order (%d) < 0 or "
	       "no so many pointers (%d), only (%d) or "
	       "first key order %d < 0", first_p, first_p + del_num,
	       B_NR_ITEMS(cur) + 1, first_i);
	if (del_num == 0)
		return;

	blkh = B_BLK_HEAD(cur);
	nr = blkh_nr_item(blkh);

	if (first_p == 0 && del_num == nr + 1) {
		RFALSE(first_i != 0,
		       "1st deleted key must have order 0, not %d", first_i);
		make_empty_node(cur_bi);
		return;
	}

	RFALSE(first_i + del_num > B_NR_ITEMS(cur),
	       "first_i = %d del_num = %d "
	       "no so many keys (%d) in the node (%b)(%z)",
	       first_i, del_num, first_i + del_num, cur, cur);

	/* deleting */
	dc = B_N_CHILD(cur, first_p);

	memmove(dc, dc + del_num, (nr + 1 - first_p - del_num) * DC_SIZE);
	key = B_N_PDELIM_KEY(cur, first_i);
	memmove(key, key + del_num,
		(nr - first_i - del_num) * KEY_SIZE + (nr + 1 -
						       del_num) * DC_SIZE);

	/* sizes, item number */
	set_blkh_nr_item(blkh, blkh_nr_item(blkh) - del_num);
	set_blkh_free_space(blkh,
			    blkh_free_space(blkh) +
			    (del_num * (KEY_SIZE + DC_SIZE)));

	do_balance_mark_internal_dirty(cur_bi->tb, cur, 0);
	/*&&&&&&&&&&&&&&&&&&&&&&& */
	check_internal(cur);
	/*&&&&&&&&&&&&&&&&&&&&&&& */

	if (cur_bi->bi_parent) {
		struct disk_child *t_dc;
		t_dc = B_N_CHILD(cur_bi->bi_parent, cur_bi->bi_position);
		put_dc_size(t_dc,
			    dc_size(t_dc) - (del_num * (KEY_SIZE + DC_SIZE)));

		do_balance_mark_internal_dirty(cur_bi->tb, cur_bi->bi_parent,
					       0);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */
		check_internal(cur_bi->bi_parent);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */
	}
}

/* delete n node pointers and items starting from given position */
static void internal_delete_childs(struct buffer_info *cur_bi, int from, int n)
{
	int i_from;

	i_from = (from == 0) ? from : from - 1;

	/* delete n pointers starting from `from' position in CUR;
	   delete n keys starting from 'i_from' position in CUR;
	 */
	internal_delete_pointers_items(cur_bi, from, i_from, n);
}

/* copy cpy_num node pointers and cpy_num - 1 items from buffer src to buffer dest
* last_first == FIRST_TO_LAST means, that we copy first items from src to tail of dest
 * last_first == LAST_TO_FIRST means, that we copy last items from src to head of dest 
 */
static void internal_copy_pointers_items(struct buffer_info *dest_bi,
					 struct buffer_head *src,
					 int last_first, int cpy_num)
{
	/* ATTENTION! Number of node pointers in DEST is equal to number of items in DEST *
	 * as delimiting key have already inserted to buffer dest.*/
	struct buffer_head *dest = dest_bi->bi_bh;
	int nr_dest, nr_src;
	int dest_order, src_order;
	struct block_head *blkh;
	struct reiserfs_key *key;
	struct disk_child *dc;

	nr_src = B_NR_ITEMS(src);

	RFALSE(dest == NULL || src == NULL,
	       "src (%p) or dest (%p) buffer is 0", src, dest);
	RFALSE(last_first != FIRST_TO_LAST && last_first != LAST_TO_FIRST,
	       "invalid last_first parameter (%d)", last_first);
	RFALSE(nr_src < cpy_num - 1,
	       "no so many items (%d) in src (%d)", cpy_num, nr_src);
	RFALSE(cpy_num < 0, "cpy_num less than 0 (%d)", cpy_num);
	RFALSE(cpy_num - 1 + B_NR_ITEMS(dest) > (int)MAX_NR_KEY(dest),
	       "cpy_num (%d) + item number in dest (%d) can not be > MAX_NR_KEY(%d)",
	       cpy_num, B_NR_ITEMS(dest), MAX_NR_KEY(dest));

	if (cpy_num == 0)
		return;

	/* coping */
	blkh = B_BLK_HEAD(dest);
	nr_dest = blkh_nr_item(blkh);

	/*dest_order = (last_first == LAST_TO_FIRST) ? 0 : nr_dest; */
	/*src_order = (last_first == LAST_TO_FIRST) ? (nr_src - cpy_num + 1) : 0; */
	(last_first == LAST_TO_FIRST) ? (dest_order = 0, src_order =
					 nr_src - cpy_num + 1) : (dest_order =
								  nr_dest,
								  src_order =
								  0);

	/* prepare space for cpy_num pointers */
	dc = B_N_CHILD(dest, dest_order);

	memmove(dc + cpy_num, dc, (nr_dest - dest_order) * DC_SIZE);

	/* insert pointers */
	memcpy(dc, B_N_CHILD(src, src_order), DC_SIZE * cpy_num);

	/* prepare space for cpy_num - 1 item headers */
	key = B_N_PDELIM_KEY(dest, dest_order);
	memmove(key + cpy_num - 1, key,
		KEY_SIZE * (nr_dest - dest_order) + DC_SIZE * (nr_dest +
							       cpy_num));

	/* insert headers */
	memcpy(key, B_N_PDELIM_KEY(src, src_order), KEY_SIZE * (cpy_num - 1));

	/* sizes, item number */
	set_blkh_nr_item(blkh, blkh_nr_item(blkh) + (cpy_num - 1));
	set_blkh_free_space(blkh,
			    blkh_free_space(blkh) - (KEY_SIZE * (cpy_num - 1) +
						     DC_SIZE * cpy_num));

	do_balance_mark_internal_dirty(dest_bi->tb, dest, 0);

	/*&&&&&&&&&&&&&&&&&&&&&&&& */
	check_internal(dest);
	/*&&&&&&&&&&&&&&&&&&&&&&&& */

	if (dest_bi->bi_parent) {
		struct disk_child *t_dc;
		t_dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
		put_dc_size(t_dc,
			    dc_size(t_dc) + (KEY_SIZE * (cpy_num - 1) +
					     DC_SIZE * cpy_num));

		do_balance_mark_internal_dirty(dest_bi->tb, dest_bi->bi_parent,
					       0);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */
		check_internal(dest_bi->bi_parent);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */
	}

}

/* Copy cpy_num node pointers and cpy_num - 1 items from buffer src to buffer dest.
 * Delete cpy_num - del_par items and node pointers from buffer src.
 * last_first == FIRST_TO_LAST means, that we copy/delete first items from src.
 * last_first == LAST_TO_FIRST means, that we copy/delete last items from src.
 */
static void internal_move_pointers_items(struct buffer_info *dest_bi,
					 struct buffer_info *src_bi,
					 int last_first, int cpy_num,
					 int del_par)
{
	int first_pointer;
	int first_item;

	internal_copy_pointers_items(dest_bi, src_bi->bi_bh, last_first,
				     cpy_num);

	if (last_first == FIRST_TO_LAST) {	/* shift_left occurs */
		first_pointer = 0;
		first_item = 0;
		/* delete cpy_num - del_par pointers and keys starting for pointers with first_pointer, 
		   for key - with first_item */
		internal_delete_pointers_items(src_bi, first_pointer,
					       first_item, cpy_num - del_par);
	} else {		/* shift_right occurs */
		int i, j;

		i = (cpy_num - del_par ==
		     (j =
		      B_NR_ITEMS(src_bi->bi_bh)) + 1) ? 0 : j - cpy_num +
		    del_par;

		internal_delete_pointers_items(src_bi,
					       j + 1 - cpy_num + del_par, i,
					       cpy_num - del_par);
	}
}

/* Insert n_src'th key of buffer src before n_dest'th key of buffer dest. */
static void internal_insert_key(struct buffer_info *dest_bi, int dest_position_before,	/* insert key before key with n_dest number */
				struct buffer_head *src, int src_position)
{
	struct buffer_head *dest = dest_bi->bi_bh;
	int nr;
	struct block_head *blkh;
	struct reiserfs_key *key;

	RFALSE(dest == NULL || src == NULL,
	       "source(%p) or dest(%p) buffer is 0", src, dest);
	RFALSE(dest_position_before < 0 || src_position < 0,
	       "source(%d) or dest(%d) key number less than 0",
	       src_position, dest_position_before);
	RFALSE(dest_position_before > B_NR_ITEMS(dest) ||
	       src_position >= B_NR_ITEMS(src),
	       "invalid position in dest (%d (key number %d)) or in src (%d (key number %d))",
	       dest_position_before, B_NR_ITEMS(dest),
	       src_position, B_NR_ITEMS(src));
	RFALSE(B_FREE_SPACE(dest) < KEY_SIZE,
	       "no enough free space (%d) in dest buffer", B_FREE_SPACE(dest));

	blkh = B_BLK_HEAD(dest);
	nr = blkh_nr_item(blkh);

	/* prepare space for inserting key */
	key = B_N_PDELIM_KEY(dest, dest_position_before);
	memmove(key + 1, key,
		(nr - dest_position_before) * KEY_SIZE + (nr + 1) * DC_SIZE);

	/* insert key */
	memcpy(key, B_N_PDELIM_KEY(src, src_position), KEY_SIZE);

	/* Change dirt, free space, item number fields. */

	set_blkh_nr_item(blkh, blkh_nr_item(blkh) + 1);
	set_blkh_free_space(blkh, blkh_free_space(blkh) - KEY_SIZE);

	do_balance_mark_internal_dirty(dest_bi->tb, dest, 0);

	if (dest_bi->bi_parent) {
		struct disk_child *t_dc;
		t_dc = B_N_CHILD(dest_bi->bi_parent, dest_bi->bi_position);
		put_dc_size(t_dc, dc_size(t_dc) + KEY_SIZE);

		do_balance_mark_internal_dirty(dest_bi->tb, dest_bi->bi_parent,
					       0);
	}
}

/* Insert d_key'th (delimiting) key from buffer cfl to tail of dest. 
 * Copy pointer_amount node pointers and pointer_amount - 1 items from buffer src to buffer dest.
 * Replace  d_key'th key in buffer cfl.
 * Delete pointer_amount items and node pointers from buffer src.
 */
/* this can be invoked both to shift from S to L and from R to S */
static void internal_shift_left(int mode,	/* INTERNAL_FROM_S_TO_L | INTERNAL_FROM_R_TO_S */
				struct tree_balance *tb,
				int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(mode, tb, h, &dest_bi, &src_bi,
				       &d_key_position, &cf);

	/*printk("pointer_amount = %d\n",pointer_amount); */

	if (pointer_amount) {
		/* insert delimiting key from common father of dest and src to node dest into position B_NR_ITEM(dest) */
		internal_insert_key(&dest_bi, B_NR_ITEMS(dest_bi.bi_bh), cf,
				    d_key_position);

		if (B_NR_ITEMS(src_bi.bi_bh) == pointer_amount - 1) {
			if (src_bi.bi_position /*src->b_item_order */  == 0)
				replace_key(tb, cf, d_key_position,
					    src_bi.
					    bi_parent /*src->b_parent */ , 0);
		} else
			replace_key(tb, cf, d_key_position, src_bi.bi_bh,
				    pointer_amount - 1);
	}
	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, FIRST_TO_LAST,
				     pointer_amount, 0);

}

/* Insert delimiting key to L[h].
 * Copy n node pointers and n - 1 items from buffer S[h] to L[h].
 * Delete n - 1 items and node pointers from buffer S[h].
 */
/* it always shifts from S[h] to L[h] */
static void internal_shift1_left(struct tree_balance *tb,
				 int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
				       &dest_bi, &src_bi, &d_key_position, &cf);

	if (pointer_amount > 0)	/* insert lkey[h]-th key  from CFL[h] to left neighbor L[h] */
		internal_insert_key(&dest_bi, B_NR_ITEMS(dest_bi.bi_bh), cf,
				    d_key_position);
	/*            internal_insert_key (tb->L[h], B_NR_ITEM(tb->L[h]), tb->CFL[h], tb->lkey[h]); */

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, FIRST_TO_LAST,
				     pointer_amount, 1);
	/*    internal_move_pointers_items (tb->L[h], tb->S[h], FIRST_TO_LAST, pointer_amount, 1); */
}

/* Insert d_key'th (delimiting) key from buffer cfr to head of dest. 
 * Copy n node pointers and n - 1 items from buffer src to buffer dest.
 * Replace  d_key'th key in buffer cfr.
 * Delete n items and node pointers from buffer src.
 */
static void internal_shift_right(int mode,	/* INTERNAL_FROM_S_TO_R | INTERNAL_FROM_L_TO_S */
				 struct tree_balance *tb,
				 int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;
	int nr;

	internal_define_dest_src_infos(mode, tb, h, &dest_bi, &src_bi,
				       &d_key_position, &cf);

	nr = B_NR_ITEMS(src_bi.bi_bh);

	if (pointer_amount > 0) {
		/* insert delimiting key from common father of dest and src to dest node into position 0 */
		internal_insert_key(&dest_bi, 0, cf, d_key_position);
		if (nr == pointer_amount - 1) {
			RFALSE(src_bi.bi_bh != PATH_H_PBUFFER(tb->tb_path, h) /*tb->S[h] */ ||
			       dest_bi.bi_bh != tb->R[h],
			       "src (%p) must be == tb->S[h](%p) when it disappears",
			       src_bi.bi_bh, PATH_H_PBUFFER(tb->tb_path, h));
			/* when S[h] disappers replace left delemiting key as well */
			if (tb->CFL[h])
				replace_key(tb, cf, d_key_position, tb->CFL[h],
					    tb->lkey[h]);
		} else
			replace_key(tb, cf, d_key_position, src_bi.bi_bh,
				    nr - pointer_amount);
	}

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, LAST_TO_FIRST,
				     pointer_amount, 0);
}

/* Insert delimiting key to R[h].
 * Copy n node pointers and n - 1 items from buffer S[h] to R[h].
 * Delete n - 1 items and node pointers from buffer S[h].
 */
/* it always shift from S[h] to R[h] */
static void internal_shift1_right(struct tree_balance *tb,
				  int h, int pointer_amount)
{
	struct buffer_info dest_bi, src_bi;
	struct buffer_head *cf;
	int d_key_position;

	internal_define_dest_src_infos(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
				       &dest_bi, &src_bi, &d_key_position, &cf);

	if (pointer_amount > 0)	/* insert rkey from CFR[h] to right neighbor R[h] */
		internal_insert_key(&dest_bi, 0, cf, d_key_position);
	/*            internal_insert_key (tb->R[h], 0, tb->CFR[h], tb->rkey[h]); */

	/* last parameter is del_parameter */
	internal_move_pointers_items(&dest_bi, &src_bi, LAST_TO_FIRST,
				     pointer_amount, 1);
	/*    internal_move_pointers_items (tb->R[h], tb->S[h], LAST_TO_FIRST, pointer_amount, 1); */
}

/* Delete insert_num node pointers together with their left items
 * and balance current node.*/
static void balance_internal_when_delete(struct tree_balance *tb,
					 int h, int child_pos)
{
	int insert_num;
	int n;
	struct buffer_head *tbSh = PATH_H_PBUFFER(tb->tb_path, h);
	struct buffer_info bi;

	insert_num = tb->insert_size[h] / ((int)(DC_SIZE + KEY_SIZE));

	/* delete child-node-pointer(s) together with their left item(s) */
	bi.tb = tb;
	bi.bi_bh = tbSh;
	bi.bi_parent = PATH_H_PPARENT(tb->tb_path, h);
	bi.bi_position = PATH_H_POSITION(tb->tb_path, h + 1);

	internal_delete_childs(&bi, child_pos, -insert_num);

	RFALSE(tb->blknum[h] > 1,
	       "tb->blknum[%d]=%d when insert_size < 0", h, tb->blknum[h]);

	n = B_NR_ITEMS(tbSh);

	if (tb->lnum[h] == 0 && tb->rnum[h] == 0) {
		if (tb->blknum[h] == 0) {
			/* node S[h] (root of the tree) is empty now */
			struct buffer_head *new_root;

			RFALSE(n
			       || B_FREE_SPACE(tbSh) !=
			       MAX_CHILD_SIZE(tbSh) - DC_SIZE,
			       "buffer must have only 0 keys (%d)", n);
			RFALSE(bi.bi_parent, "root has parent (%p)",
			       bi.bi_parent);

			/* choose a new root */
			if (!tb->L[h - 1] || !B_NR_ITEMS(tb->L[h - 1]))
				new_root = tb->R[h - 1];
			else
				new_root = tb->L[h - 1];
			/* switch super block's tree root block number to the new value */
			PUT_SB_ROOT_BLOCK(tb->tb_sb, new_root->b_blocknr);
			//REISERFS_SB(tb->tb_sb)->s_rs->s_tree_height --;
			PUT_SB_TREE_HEIGHT(tb->tb_sb,
					   SB_TREE_HEIGHT(tb->tb_sb) - 1);

			do_balance_mark_sb_dirty(tb,
						 REISERFS_SB(tb->tb_sb)->s_sbh,
						 1);
			/*&&&&&&&&&&&&&&&&&&&&&& */
			if (h > 1)
				/* use check_internal if new root is an internal node */
				check_internal(new_root);
			/*&&&&&&&&&&&&&&&&&&&&&& */

			/* do what is needed for buffer thrown from tree */
			reiserfs_invalidate_buffer(tb, tbSh);
			return;
		}
		return;
	}

	if (tb->L[h] && tb->lnum[h] == -B_NR_ITEMS(tb->L[h]) - 1) {	/* join S[h] with L[h] */

		RFALSE(tb->rnum[h] != 0,
		       "invalid tb->rnum[%d]==%d when joining S[h] with L[h]",
		       h, tb->rnum[h]);

		internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h, n + 1);
		reiserfs_invalidate_buffer(tb, tbSh);

		return;
	}

	if (tb->R[h] && tb->rnum[h] == -B_NR_ITEMS(tb->R[h]) - 1) {	/* join S[h] with R[h] */
		RFALSE(tb->lnum[h] != 0,
		       "invalid tb->lnum[%d]==%d when joining S[h] with R[h]",
		       h, tb->lnum[h]);

		internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h, n + 1);

		reiserfs_invalidate_buffer(tb, tbSh);
		return;
	}

	if (tb->lnum[h] < 0) {	/* borrow from left neighbor L[h] */
		RFALSE(tb->rnum[h] != 0,
		       "wrong tb->rnum[%d]==%d when borrow from L[h]", h,
		       tb->rnum[h]);
		/*internal_shift_right (tb, h, tb->L[h], tb->CFL[h], tb->lkey[h], tb->S[h], -tb->lnum[h]); */
		internal_shift_right(INTERNAL_SHIFT_FROM_L_TO_S, tb, h,
				     -tb->lnum[h]);
		return;
	}

	if (tb->rnum[h] < 0) {	/* borrow from right neighbor R[h] */
		RFALSE(tb->lnum[h] != 0,
		       "invalid tb->lnum[%d]==%d when borrow from R[h]",
		       h, tb->lnum[h]);
		internal_shift_left(INTERNAL_SHIFT_FROM_R_TO_S, tb, h, -tb->rnum[h]);	/*tb->S[h], tb->CFR[h], tb->rkey[h], tb->R[h], -tb->rnum[h]); */
		return;
	}

	if (tb->lnum[h] > 0) {	/* split S[h] into two parts and put them into neighbors */
		RFALSE(tb->rnum[h] == 0 || tb->lnum[h] + tb->rnum[h] != n + 1,
		       "invalid tb->lnum[%d]==%d or tb->rnum[%d]==%d when S[h](item number == %d) is split between them",
		       h, tb->lnum[h], h, tb->rnum[h], n);

		internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h, tb->lnum[h]);	/*tb->L[h], tb->CFL[h], tb->lkey[h], tb->S[h], tb->lnum[h]); */
		internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
				     tb->rnum[h]);

		reiserfs_invalidate_buffer(tb, tbSh);

		return;
	}
	reiserfs_panic(tb->tb_sb,
		       "balance_internal_when_delete: unexpected tb->lnum[%d]==%d or tb->rnum[%d]==%d",
		       h, tb->lnum[h], h, tb->rnum[h]);
}

/* Replace delimiting key of buffers L[h] and S[h] by the given key.*/
static void replace_lkey(struct tree_balance *tb, int h, struct item_head *key)
{
	RFALSE(tb->L[h] == NULL || tb->CFL[h] == NULL,
	       "L[h](%p) and CFL[h](%p) must exist in replace_lkey",
	       tb->L[h], tb->CFL[h]);

	if (B_NR_ITEMS(PATH_H_PBUFFER(tb->tb_path, h)) == 0)
		return;

	memcpy(B_N_PDELIM_KEY(tb->CFL[h], tb->lkey[h]), key, KEY_SIZE);

	do_balance_mark_internal_dirty(tb, tb->CFL[h], 0);
}

/* Replace delimiting key of buffers S[h] and R[h] by the given key.*/
static void replace_rkey(struct tree_balance *tb, int h, struct item_head *key)
{
	RFALSE(tb->R[h] == NULL || tb->CFR[h] == NULL,
	       "R[h](%p) and CFR[h](%p) must exist in replace_rkey",
	       tb->R[h], tb->CFR[h]);
	RFALSE(B_NR_ITEMS(tb->R[h]) == 0,
	       "R[h] can not be empty if it exists (item number=%d)",
	       B_NR_ITEMS(tb->R[h]));

	memcpy(B_N_PDELIM_KEY(tb->CFR[h], tb->rkey[h]), key, KEY_SIZE);

	do_balance_mark_internal_dirty(tb, tb->CFR[h], 0);
}

int balance_internal(struct tree_balance *tb,	/* tree_balance structure               */
		     int h,	/* level of the tree                    */
		     int child_pos, struct item_head *insert_key,	/* key for insertion on higher level    */
		     struct buffer_head **insert_ptr	/* node for insertion on higher level */
    )
    /* if inserting/pasting
       {
       child_pos is the position of the node-pointer in S[h] that        *
       pointed to S[h-1] before balancing of the h-1 level;              *
       this means that new pointers and items must be inserted AFTER *
       child_pos
       }
       else 
       {
       it is the position of the leftmost pointer that must be deleted (together with
       its corresponding key to the left of the pointer)
       as a result of the previous level's balancing.
       }
     */
{
	struct buffer_head *tbSh = PATH_H_PBUFFER(tb->tb_path, h);
	struct buffer_info bi;
	int order;		/* we return this: it is 0 if there is no S[h], else it is tb->S[h]->b_item_order */
	int insert_num, n, k;
	struct buffer_head *S_new;
	struct item_head new_insert_key;
	struct buffer_head *new_insert_ptr = NULL;
	struct item_head *new_insert_key_addr = insert_key;

	RFALSE(h < 1, "h (%d) can not be < 1 on internal level", h);

	PROC_INFO_INC(tb->tb_sb, balance_at[h]);

	order =
	    (tbSh) ? PATH_H_POSITION(tb->tb_path,
				     h + 1) /*tb->S[h]->b_item_order */ : 0;

	/* Using insert_size[h] calculate the number insert_num of items
	   that must be inserted to or deleted from S[h]. */
	insert_num = tb->insert_size[h] / ((int)(KEY_SIZE + DC_SIZE));

	/* Check whether insert_num is proper * */
	RFALSE(insert_num < -2 || insert_num > 2,
	       "incorrect number of items inserted to the internal node (%d)",
	       insert_num);
	RFALSE(h > 1 && (insert_num > 1 || insert_num < -1),
	       "incorrect number of items (%d) inserted to the internal node on a level (h=%d) higher than last internal level",
	       insert_num, h);

	/* Make balance in case insert_num < 0 */
	if (insert_num < 0) {
		balance_internal_when_delete(tb, h, child_pos);
		return order;
	}

	k = 0;
	if (tb->lnum[h] > 0) {
		/* shift lnum[h] items from S[h] to the left neighbor L[h].
		   check how many of new items fall into L[h] or CFL[h] after
		   shifting */
		n = B_NR_ITEMS(tb->L[h]);	/* number of items in L[h] */
		if (tb->lnum[h] <= child_pos) {
			/* new items don't fall into L[h] or CFL[h] */
			internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
					    tb->lnum[h]);
			/*internal_shift_left (tb->L[h],tb->CFL[h],tb->lkey[h],tbSh,tb->lnum[h]); */
			child_pos -= tb->lnum[h];
		} else if (tb->lnum[h] > child_pos + insert_num) {
			/* all new items fall into L[h] */
			internal_shift_left(INTERNAL_SHIFT_FROM_S_TO_L, tb, h,
					    tb->lnum[h] - insert_num);
			/*                  internal_shift_left(tb->L[h],tb->CFL[h],tb->lkey[h],tbSh,
			   tb->lnum[h]-insert_num);
			 */
			/* insert insert_num keys and node-pointers into L[h] */
			bi.tb = tb;
			bi.bi_bh = tb->L[h];
			bi.bi_parent = tb->FL[h];
			bi.bi_position = get_left_neighbor_position(tb, h);
			internal_insert_childs(&bi,
					       /*tb->L[h], tb->S[h-1]->b_next */
					       n + child_pos + 1,
					       insert_num, insert_key,
					       insert_ptr);

			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* some items fall into L[h] or CFL[h], but some don't fall */
			internal_shift1_left(tb, h, child_pos + 1);
			/* calculate number of new items that fall into L[h] */
			k = tb->lnum[h] - child_pos - 1;
			bi.tb = tb;
			bi.bi_bh = tb->L[h];
			bi.bi_parent = tb->FL[h];
			bi.bi_position = get_left_neighbor_position(tb, h);
			internal_insert_childs(&bi,
					       /*tb->L[h], tb->S[h-1]->b_next, */
					       n + child_pos + 1, k,
					       insert_key, insert_ptr);

			replace_lkey(tb, h, insert_key + k);

			/* replace the first node-ptr in S[h] by node-ptr to insert_ptr[k] */
			dc = B_N_CHILD(tbSh, 0);
			put_dc_size(dc,
				    MAX_CHILD_SIZE(insert_ptr[k]) -
				    B_FREE_SPACE(insert_ptr[k]));
			put_dc_block_number(dc, insert_ptr[k]->b_blocknr);

			do_balance_mark_internal_dirty(tb, tbSh, 0);

			k++;
			insert_key += k;
			insert_ptr += k;
			insert_num -= k;
			child_pos = 0;
		}
	}
	/* tb->lnum[h] > 0 */
	if (tb->rnum[h] > 0) {
		/*shift rnum[h] items from S[h] to the right neighbor R[h] */
		/* check how many of new items fall into R or CFR after shifting */
		n = B_NR_ITEMS(tbSh);	/* number of items in S[h] */
		if (n - tb->rnum[h] >= child_pos)
			/* new items fall into S[h] */
			/*internal_shift_right(tb,h,tbSh,tb->CFR[h],tb->rkey[h],tb->R[h],tb->rnum[h]); */
			internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
					     tb->rnum[h]);
		else if (n + insert_num - tb->rnum[h] < child_pos) {
			/* all new items fall into R[h] */
			/*internal_shift_right(tb,h,tbSh,tb->CFR[h],tb->rkey[h],tb->R[h],
			   tb->rnum[h] - insert_num); */
			internal_shift_right(INTERNAL_SHIFT_FROM_S_TO_R, tb, h,
					     tb->rnum[h] - insert_num);

			/* insert insert_num keys and node-pointers into R[h] */
			bi.tb = tb;
			bi.bi_bh = tb->R[h];
			bi.bi_parent = tb->FR[h];
			bi.bi_position = get_right_neighbor_position(tb, h);
			internal_insert_childs(&bi,
					       /*tb->R[h],tb->S[h-1]->b_next */
					       child_pos - n - insert_num +
					       tb->rnum[h] - 1,
					       insert_num, insert_key,
					       insert_ptr);
			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* one of the items falls into CFR[h] */
			internal_shift1_right(tb, h, n - child_pos + 1);
			/* calculate number of new items that fall into R[h] */
			k = tb->rnum[h] - n + child_pos - 1;
			bi.tb = tb;
			bi.bi_bh = tb->R[h];
			bi.bi_parent = tb->FR[h];
			bi.bi_position = get_right_neighbor_position(tb, h);
			internal_insert_childs(&bi,
					       /*tb->R[h], tb->R[h]->b_child, */
					       0, k, insert_key + 1,
					       insert_ptr + 1);

			replace_rkey(tb, h, insert_key + insert_num - k - 1);

			/* replace the first node-ptr in R[h] by node-ptr insert_ptr[insert_num-k-1] */
			dc = B_N_CHILD(tb->R[h], 0);
			put_dc_size(dc,
				    MAX_CHILD_SIZE(insert_ptr
						   [insert_num - k - 1]) -
				    B_FREE_SPACE(insert_ptr
						 [insert_num - k - 1]));
			put_dc_block_number(dc,
					    insert_ptr[insert_num - k -
						       1]->b_blocknr);

			do_balance_mark_internal_dirty(tb, tb->R[h], 0);

			insert_num -= (k + 1);
		}
	}

    /** Fill new node that appears instead of S[h] **/
	RFALSE(tb->blknum[h] > 2, "blknum can not be > 2 for internal level");
	RFALSE(tb->blknum[h] < 0, "blknum can not be < 0");

	if (!tb->blknum[h]) {	/* node S[h] is empty now */
		RFALSE(!tbSh, "S[h] is equal NULL");

		/* do what is needed for buffer thrown from tree */
		reiserfs_invalidate_buffer(tb, tbSh);
		return order;
	}

	if (!tbSh) {
		/* create new root */
		struct disk_child *dc;
		struct buffer_head *tbSh_1 = PATH_H_PBUFFER(tb->tb_path, h - 1);
		struct block_head *blkh;

		if (tb->blknum[h] != 1)
			reiserfs_panic(NULL,
				       "balance_internal: One new node required for creating the new root");
		/* S[h] = empty buffer from the list FEB. */
		tbSh = get_FEB(tb);
		blkh = B_BLK_HEAD(tbSh);
		set_blkh_level(blkh, h + 1);

		/* Put the unique node-pointer to S[h] that points to S[h-1]. */

		dc = B_N_CHILD(tbSh, 0);
		put_dc_block_number(dc, tbSh_1->b_blocknr);
		put_dc_size(dc,
			    (MAX_CHILD_SIZE(tbSh_1) - B_FREE_SPACE(tbSh_1)));

		tb->insert_size[h] -= DC_SIZE;
		set_blkh_free_space(blkh, blkh_free_space(blkh) - DC_SIZE);

		do_balance_mark_internal_dirty(tb, tbSh, 0);

		/*&&&&&&&&&&&&&&&&&&&&&&&& */
		check_internal(tbSh);
		/*&&&&&&&&&&&&&&&&&&&&&&&& */

		/* put new root into path structure */
		PATH_OFFSET_PBUFFER(tb->tb_path, ILLEGAL_PATH_ELEMENT_OFFSET) =
		    tbSh;

		/* Change root in structure super block. */
		PUT_SB_ROOT_BLOCK(tb->tb_sb, tbSh->b_blocknr);
		PUT_SB_TREE_HEIGHT(tb->tb_sb, SB_TREE_HEIGHT(tb->tb_sb) + 1);
		do_balance_mark_sb_dirty(tb, REISERFS_SB(tb->tb_sb)->s_sbh, 1);
	}

	if (tb->blknum[h] == 2) {
		int snum;
		struct buffer_info dest_bi, src_bi;

		/* S_new = free buffer from list FEB */
		S_new = get_FEB(tb);

		set_blkh_level(B_BLK_HEAD(S_new), h + 1);

		dest_bi.tb = tb;
		dest_bi.bi_bh = S_new;
		dest_bi.bi_parent = NULL;
		dest_bi.bi_position = 0;
		src_bi.tb = tb;
		src_bi.bi_bh = tbSh;
		src_bi.bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		src_bi.bi_position = PATH_H_POSITION(tb->tb_path, h + 1);

		n = B_NR_ITEMS(tbSh);	/* number of items in S[h] */
		snum = (insert_num + n + 1) / 2;
		if (n - snum >= child_pos) {
			/* new items don't fall into S_new */
			/*  store the delimiting key for the next level */
			/* new_insert_key = (n - snum)'th key in S[h] */
			memcpy(&new_insert_key, B_N_PDELIM_KEY(tbSh, n - snum),
			       KEY_SIZE);
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST, snum, 0);
			/*            internal_move_pointers_items(S_new, tbSh, LAST_TO_FIRST, snum, 0); */
		} else if (n + insert_num - snum < child_pos) {
			/* all new items fall into S_new */
			/*  store the delimiting key for the next level */
			/* new_insert_key = (n + insert_item - snum)'th key in S[h] */
			memcpy(&new_insert_key,
			       B_N_PDELIM_KEY(tbSh, n + insert_num - snum),
			       KEY_SIZE);
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST,
						     snum - insert_num, 0);
			/*                  internal_move_pointers_items(S_new,tbSh,1,snum - insert_num,0); */

			/* insert insert_num keys and node-pointers into S_new */
			internal_insert_childs(&dest_bi,
					       /*S_new,tb->S[h-1]->b_next, */
					       child_pos - n - insert_num +
					       snum - 1,
					       insert_num, insert_key,
					       insert_ptr);

			insert_num = 0;
		} else {
			struct disk_child *dc;

			/* some items fall into S_new, but some don't fall */
			/* last parameter is del_par */
			internal_move_pointers_items(&dest_bi, &src_bi,
						     LAST_TO_FIRST,
						     n - child_pos + 1, 1);
			/*                  internal_move_pointers_items(S_new,tbSh,1,n - child_pos + 1,1); */
			/* calculate number of new items that fall into S_new */
			k = snum - n + child_pos - 1;

			internal_insert_childs(&dest_bi, /*S_new, */ 0, k,
					       insert_key + 1, insert_ptr + 1);

			/* new_insert_key = insert_key[insert_num - k - 1] */
			memcpy(&new_insert_key, insert_key + insert_num - k - 1,
			       KEY_SIZE);
			/* replace first node-ptr in S_new by node-ptr to insert_ptr[insert_num-k-1] */

			dc = B_N_CHILD(S_new, 0);
			put_dc_size(dc,
				    (MAX_CHILD_SIZE
				     (insert_ptr[insert_num - k - 1]) -
				     B_FREE_SPACE(insert_ptr
						  [insert_num - k - 1])));
			put_dc_block_number(dc,
					    insert_ptr[insert_num - k -
						       1]->b_blocknr);

			do_balance_mark_internal_dirty(tb, S_new, 0);

			insert_num -= (k + 1);
		}
		/* new_insert_ptr = node_pointer to S_new */
		new_insert_ptr = S_new;

		RFALSE(!buffer_journaled(S_new) || buffer_journal_dirty(S_new)
		       || buffer_dirty(S_new), "cm-00001: bad S_new (%b)",
		       S_new);

		// S_new is released in unfix_nodes
	}

	n = B_NR_ITEMS(tbSh);	/*number of items in S[h] */

	if (0 <= child_pos && child_pos <= n && insert_num > 0) {
		bi.tb = tb;
		bi.bi_bh = tbSh;
		bi.bi_parent = PATH_H_PPARENT(tb->tb_path, h);
		bi.bi_position = PATH_H_POSITION(tb->tb_path, h + 1);
		internal_insert_childs(&bi,	/*tbSh, */
				       /*          ( tb->S[h-1]->b_parent == tb->S[h] ) ? tb->S[h-1]->b_next :  tb->S[h]->b_child->b_next, */
				       child_pos, insert_num, insert_key,
				       insert_ptr);
	}

	memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
	insert_ptr[0] = new_insert_ptr;

	return order;
}