summary refs log tree commit diff
path: root/db2/btree/bt_cursor.c
blob: e5f3faeb70e18496e82ac70e2dd42798c889c5f9 (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
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997
 *	Sleepycat Software.  All rights reserved.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)bt_cursor.c	10.35 (Sleepycat) 10/25/97";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "btree.h"

static int __bam_c_close __P((DBC *));
static int __bam_c_del __P((DBC *, int));
static int __bam_c_first __P((DB *, CURSOR *));
static int __bam_c_get __P((DBC *, DBT *, DBT *, int));
static int __bam_c_last __P((DB *, CURSOR *));
static int __bam_c_next __P((DB *, CURSOR *, int));
static int __bam_c_physdel __P((DB *, CURSOR *, PAGE *));
static int __bam_c_prev __P((DB *, CURSOR *));
static int __bam_c_put __P((DBC *, DBT *, DBT *, int));
static int __bam_c_rget __P((DB *, CURSOR *, DBT *, DBT *, int));
static int __bam_c_search __P((DB *, CURSOR *, const DBT *, u_int, int, int *));

/* Discard the current page/lock held by a cursor. */
#undef	DISCARD
#define	DISCARD(dbp, cp) {						\
	(void)memp_fput(dbp->mpf, (cp)->page, 0);			\
	(cp)->page = NULL;						\
	(void)__BT_TLPUT((dbp), (cp)->lock);				\
	(cp)->lock = LOCK_INVALID;					\
}

/*
 * __bam_cursor --
 *	Interface to the cursor functions.
 *
 * PUBLIC: int __bam_cursor __P((DB *, DB_TXN *, DBC **));
 */
int
__bam_cursor(dbp, txn, dbcp)
	DB *dbp;
	DB_TXN *txn;
	DBC **dbcp;
{
	CURSOR *cp;
	DBC *dbc;

	DEBUG_LWRITE(dbp, txn, "bam_cursor", NULL, NULL, 0);

	if ((dbc = (DBC *)__db_calloc(1, sizeof(DBC))) == NULL)
		return (ENOMEM);
	if ((cp = (CURSOR *)__db_calloc(1, sizeof(CURSOR))) == NULL) {
		__db_free(dbc);
		return (ENOMEM);
	}

	cp->dbc = dbc;
	cp->pgno = cp->dpgno = PGNO_INVALID;
	cp->lock = LOCK_INVALID;

	dbc->dbp = dbp;
	dbc->txn = txn;
	dbc->internal = cp;
	dbc->c_close = __bam_c_close;
	dbc->c_del = __bam_c_del;
	dbc->c_get = __bam_c_get;
	dbc->c_put = __bam_c_put;

	/*
	 * All cursors are queued from the master DB structure.  Add the
	 * cursor to that queue.
	 */
	DB_THREAD_LOCK(dbp);
	TAILQ_INSERT_HEAD(&dbp->curs_queue, dbc, links);
	DB_THREAD_UNLOCK(dbp);

	*dbcp = dbc;
	return (0);
}

/*
 * __bam_c_close --
 *	Close a single cursor.
 */
static int
__bam_c_close(dbc)
	DBC *dbc;
{
	DB *dbp;
	int ret;

	DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_close", NULL, NULL, 0);

	GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);

	ret = __bam_c_iclose(dbp, dbc);

	PUTHANDLE(dbp);
	return (ret);
}

/*
 * __bam_c_iclose --
 *	Close a single cursor -- internal version.
 *
 * PUBLIC: int __bam_c_iclose __P((DB *, DBC *));
 */
int
__bam_c_iclose(dbp, dbc)
	DB *dbp;
	DBC *dbc;
{
	CURSOR *cp;
	int ret;

	cp = dbc->internal;

	/* If a cursor key was deleted, perform the actual deletion.  */
	ret = F_ISSET(cp, C_DELETED) ? __bam_c_physdel(dbp, cp, NULL) : 0;

	/* Discard any lock if we're not inside a transaction. */
	if (cp->lock != LOCK_INVALID)
		(void)__BT_TLPUT(dbp, cp->lock);

	/*
	 * All cursors are queued from the master DB structure.  Remove the
	 * cursor from that queue.
	 */
	DB_THREAD_LOCK(dbc->dbp);
	TAILQ_REMOVE(&dbc->dbp->curs_queue, dbc, links);
	DB_THREAD_UNLOCK(dbc->dbp);

	/* Discard the structures. */
	FREE(dbc->internal, sizeof(CURSOR));
	FREE(dbc, sizeof(DBC));

	return (ret);
}

/*
 * __bam_c_del --
 *	Delete using a cursor.
 */
static int
__bam_c_del(dbc, flags)
	DBC *dbc;
	int flags;
{
	CURSOR *cp;
	DB *dbp;
	DB_LOCK lock;
	PAGE *h;
	db_pgno_t pgno;
	db_indx_t indx;
	int ret;

	DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_del", NULL, NULL, flags);

	cp = dbc->internal;

	/* Check for invalid flags. */
	if ((ret = __db_cdelchk(dbc->dbp, flags,
	    F_ISSET(dbc->dbp, DB_AM_RDONLY), cp->pgno != PGNO_INVALID)) != 0)
		return (ret);

	/* If already deleted, return failure. */
	if (F_ISSET(cp, C_DELETED | C_REPLACE))
		return (DB_KEYEMPTY);

	GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);

	/*
	 * We don't physically delete the record until the cursor moves,
	 * so we have to have a long-lived write lock on the page instead
	 * of a long-lived read lock.  Note, we have to have a read lock
	 * to even get here, so we simply discard it.
	 */
	if (F_ISSET(dbp, DB_AM_LOCKING) && cp->mode != DB_LOCK_WRITE) {
		if ((ret = __bam_lget(dbp,
		    0, cp->pgno, DB_LOCK_WRITE, &lock)) != 0)
			goto err;
		(void)__BT_TLPUT(dbp, cp->lock);
		cp->lock = lock;
		cp->mode = DB_LOCK_WRITE;
	}

	/*
	 * Acquire the underlying page (which may be different from the above
	 * page because it may be a duplicate page), and set the on-page and
	 * in-cursor delete flags.  We don't need to lock it as we've already
	 * write-locked the page leading to it.
	 */
	if (cp->dpgno == PGNO_INVALID) {
		pgno = cp->pgno;
		indx = cp->indx;
	} else {
		pgno = cp->dpgno;
		indx = cp->dindx;
	}

	if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
		goto err;

	/* Log the change. */
	if (DB_LOGGING(dbp) &&
	    (ret = __bam_cdel_log(dbp->dbenv->lg_info, dbp->txn, &LSN(h),
	    0, dbp->log_fileid, PGNO(h), &LSN(h), indx)) != 0) {
		(void)memp_fput(dbp->mpf, h, 0);
		goto err;
	}

	/* Set the intent-to-delete flag on the page and in all cursors. */
	if (cp->dpgno == PGNO_INVALID)
		B_DSET(GET_BKEYDATA(h, indx + O_INDX)->type);
	else
		B_DSET(GET_BKEYDATA(h, indx)->type);
	(void)__bam_ca_delete(dbp, pgno, indx, NULL);

	ret = memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);

err:	PUTHANDLE(dbp);
	return (ret);
}

/*
 * __bam_get --
 *	Retrieve a key/data pair from the tree.
 *
 * PUBLIC: int __bam_get __P((DB *, DB_TXN *, DBT *, DBT *, int));
 */
int
__bam_get(argdbp, txn, key, data, flags)
	DB *argdbp;
	DB_TXN *txn;
	DBT *key, *data;
	int flags;
{
	DBC dbc;
	CURSOR cp;
	int ret;

	DEBUG_LREAD(argdbp, txn, "bam_get", key, NULL, flags);

	/* Check for invalid flags. */
	if ((ret = __db_getchk(argdbp, key, data, flags)) != 0)
		return (ret);

	/* Build an internal cursor. */
	memset(&cp, 0, sizeof(cp));
	cp.dbc = &dbc;
	cp.pgno = cp.dpgno = PGNO_INVALID;
	cp.lock = LOCK_INVALID;
	cp.flags = C_INTERNAL;

	/* Build an external cursor. */
	memset(&dbc, 0, sizeof(dbc));
	dbc.dbp = argdbp;
	dbc.txn = txn;
	dbc.internal = &cp;

	/* Get the key. */
	return(__bam_c_get(&dbc,
	    key, data, LF_ISSET(DB_SET_RECNO) ? DB_SET_RECNO : DB_SET));
}

/*
 * __bam_c_get --
 *	Get using a cursor (btree).
 */
static int
__bam_c_get(dbc, key, data, flags)
	DBC *dbc;
	DBT *key, *data;
	int flags;
{
	BTREE *t;
	CURSOR *cp, copy;
	DB *dbp;
	PAGE *h;
	int exact, ret;

	DEBUG_LREAD(dbc->dbp, dbc->txn, "bam_c_get",
	    flags == DB_SET || flags == DB_SET_RANGE ? key : NULL, NULL, flags);

	cp = dbc->internal;

	/* Check for invalid flags. */
	if ((ret = __db_cgetchk(dbc->dbp,
	    key, data, flags, cp->pgno != PGNO_INVALID)) != 0)
		return (ret);

	GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
	t = dbp->internal;

	/*
	 * Break out the code to return a cursor's record number.  It
	 * has nothing to do with the cursor get code except that it's
	 * been rammed into the interface.
	 */
	if (LF_ISSET(DB_GET_RECNO)) {
		ret = __bam_c_rget(dbp, cp, key, data, flags);
		PUTHANDLE(dbp);
		return (ret);
	}

	/* Initialize the cursor for a new retrieval. */
	copy = *cp;
	cp->page = NULL;
	cp->lock = LOCK_INVALID;

	switch (flags) {
	case DB_CURRENT:
		/* It's not possible to return a deleted record. */
		if (F_ISSET(cp, C_DELETED | C_REPLACE)) {
			PUTHANDLE(dbp);
			return (DB_KEYEMPTY);
		}

		/* Get the page with the current item on it. */
		if ((ret = __bam_pget(dbp, &cp->page, &cp->pgno, 0)) != 0)
			goto err;
		break;
	case DB_NEXT:
		if (cp->pgno != PGNO_INVALID) {
			if ((ret = __bam_c_next(dbp, cp, 1)) != 0)
				goto err;
			break;
		}
		/* FALLTHROUGH */
	case DB_FIRST:
		if ((ret = __bam_c_first(dbp, cp)) != 0)
			goto err;
		break;
	case DB_PREV:
		if (cp->pgno != PGNO_INVALID) {
			if ((ret = __bam_c_prev(dbp, cp)) != 0)
				goto err;
			break;
		}
		/* FALLTHROUGH */
	case DB_LAST:
		if ((ret = __bam_c_last(dbp, cp)) != 0)
			goto err;
		break;
	case DB_SET_RECNO:
		exact = 1;
		if ((ret =
		    __bam_c_search(dbp, cp, key, S_FIND, 1, &exact)) != 0)
			goto err;
		break;
	case DB_SET:
		exact = 1;
		if ((ret =
		    __bam_c_search(dbp, cp, key, S_FIND, 0, &exact)) != 0)
			goto err;
		break;
	case DB_SET_RANGE:
		exact = 0;
		if ((ret =
		    __bam_c_search(dbp, cp, key, S_FIND, 0, &exact)) != 0)
			goto err;
		break;
	}

	/*
	 * Return the key if the user didn't give us one.  If we've moved to
	 * a duplicate page, we may no longer have a pointer to the main page,
	 * so we have to go get it.  We know that it's already read-locked,
	 * however, so we don't have to acquire a new lock.
	 */
	if (flags != DB_SET) {
		if (cp->dpgno != PGNO_INVALID) {
			if ((ret = __bam_pget(dbp, &h, &cp->pgno, 0)) != 0)
				goto err;
		} else
			h = cp->page;
		ret = __db_ret(dbp,
		    h, cp->indx, key, &t->bt_rkey.data, &t->bt_rkey.ulen);
		if (cp->dpgno != PGNO_INVALID)
			(void)memp_fput(dbp->mpf, h, 0);
		if (ret)
			goto err;
	}

	/* Return the data. */
	if ((ret = __db_ret(dbp, cp->page,
	    cp->dpgno == PGNO_INVALID ? cp->indx + O_INDX : cp->dindx,
	    data, &t->bt_rdata.data, &t->bt_rdata.ulen)) != 0)
		goto err;

	/*
	 * If the previous cursor record has been deleted, delete it.  The
	 * returned key isn't a deleted key, so clear the flag.
	 */
	if (F_ISSET(&copy, C_DELETED) && __bam_c_physdel(dbp, &copy, cp->page))
		goto err;
	F_CLR(cp, C_DELETED | C_REPLACE);

	/* Release the previous lock, if any. */
	if (copy.lock != LOCK_INVALID)
		(void)__BT_TLPUT(dbp, copy.lock);

	/* Release the pinned page. */
	ret = memp_fput(dbp->mpf, cp->page, 0);

	/* Internal cursors don't hold locks. */
	if (F_ISSET(cp, C_INTERNAL) && cp->lock != LOCK_INVALID)
		(void)__BT_TLPUT(dbp, cp->lock);

	++t->lstat.bt_get;

	if (0) {
err:		if (cp->page != NULL)
			(void)memp_fput(dbp->mpf, cp->page, 0);
		if (cp->lock != LOCK_INVALID)
			(void)__BT_TLPUT(dbp, cp->lock);
		*cp = copy;
	}

	PUTHANDLE(dbp);
	return (ret);
}

/*
 * __bam_c_rget --
 *	Return the record number for a cursor.
 */
static int
__bam_c_rget(dbp, cp, key, data, flags)
	DB *dbp;
	CURSOR *cp;
	DBT *key, *data;
	int flags;
{
	BTREE *t;
	DBT dbt;
	db_recno_t recno;
	int exact, ret;

	/* Get the page with the current item on it. */
	if ((ret = __bam_pget(dbp, &cp->page, &cp->pgno, 0)) != 0)
		return (ret);

	/* Get a copy of the key. */
	memset(&dbt, 0, sizeof(DBT));
	dbt.flags = DB_DBT_MALLOC | DB_DBT_INTERNAL;
	if ((ret = __db_ret(dbp, cp->page, cp->indx, &dbt, NULL, NULL)) != 0)
		goto err;

	exact = 1;
	if ((ret = __bam_search(dbp, &dbt, S_FIND, 1, &recno, &exact)) != 0)
		goto err;

	t = dbp->internal;
	ret = __db_retcopy(data, &recno, sizeof(recno),
	    &t->bt_rdata.data, &t->bt_rdata.ulen, dbp->db_malloc);

	/* Release the stack. */
	__bam_stkrel(dbp);

err:	(void)memp_fput(dbp->mpf, cp->page, 0);
	__db_free(dbt.data);
	return (ret);
}

/*
 * __bam_c_put --
 *	Put using a cursor.
 */
static int
__bam_c_put(dbc, key, data, flags)
	DBC *dbc;
	DBT *key, *data;
	int flags;
{
	BTREE *t;
	CURSOR *cp, copy;
	DB *dbp;
	DBT dbt;
	db_indx_t indx;
	db_pgno_t pgno;
	int exact, needkey, ret;
	void *arg;

	DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_put",
	    flags == DB_KEYFIRST || flags == DB_KEYLAST ? key : NULL,
	    data, flags);

	cp = dbc->internal;

	if ((ret = __db_cputchk(dbc->dbp, key, data, flags,
	    F_ISSET(dbc->dbp, DB_AM_RDONLY), cp->pgno != PGNO_INVALID)) != 0)
		return (ret);

	GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
	t = dbp->internal;

	/* Initialize the cursor for a new retrieval. */
	copy = *cp;
	cp->page = NULL;
	cp->lock = LOCK_INVALID;

	/*
	 * To split, we need a valid key for the page.  Since it's a cursor,
	 * we have to build one.
	 */
	if (0) {
split:		if (needkey) {
			memset(&dbt, 0, sizeof(DBT));
			ret = __db_ret(dbp, cp->page, indx,
			    &dbt, &t->bt_rkey.data, &t->bt_rkey.ulen);

			DISCARD(dbp, cp);

			if (ret)
				goto err;
			arg = &dbt;
		} else {
			(void)__bam_stkrel(dbp);
			arg = key;
		}
		if ((ret = __bam_split(dbp, arg)) != 0)
			goto err;
	}

	/* If there's no key supplied, use the cursor. */
	if (flags == DB_KEYFIRST || flags == DB_KEYLAST)
		needkey = 0;
	else {
		needkey = 1;
		if (cp->dpgno == PGNO_INVALID) {
			pgno = cp->pgno;
			indx = cp->indx;
		} else {
			pgno = cp->dpgno;
			indx = cp->dindx;
		}
		/* Acquire the current page. */
		if ((ret = __bam_lget(dbp,
		    0, cp->pgno, DB_LOCK_WRITE, &cp->lock)) != 0)
			goto err;
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			goto err;
	}

	ret = 0;
	switch (flags) {
	case DB_AFTER:
	case DB_BEFORE:
	case DB_CURRENT:
		if ((ret = __bam_iitem(dbp, &cp->page,
		    &indx, key, data, flags, 0)) == DB_NEEDSPLIT)
			goto split;
		break;
	case DB_KEYFIRST:
		exact = 0;
		if ((ret =
		    __bam_c_search(dbp, cp, key, S_KEYFIRST, 0, &exact)) != 0)
			goto err;

		indx = cp->dpgno == PGNO_INVALID ? cp->indx : cp->dindx;
		if ((ret = __bam_iitem(dbp, &cp->page, &indx, key,
		    data, DB_BEFORE, exact ? 0 : BI_NEWKEY)) == DB_NEEDSPLIT)
			goto split;
		if (ret)
			goto err;
		break;
	case DB_KEYLAST:
		exact = 0;
		if ((ret =
		    __bam_c_search(dbp, cp, key, S_KEYLAST, 0, &exact)) != 0)
			goto err;

		indx = cp->dpgno == PGNO_INVALID ? cp->indx : cp->dindx;
		if ((ret = __bam_iitem(dbp, &cp->page, &indx, key,
		    data, DB_AFTER, exact ? 0 : BI_NEWKEY)) == DB_NEEDSPLIT)
			goto split;
		break;
	}
	if (ret)
		goto err;

	/*
	 * Update the cursor to point to the new entry.  The new entry was
	 * stored on the current page, because we split pages until it was
	 * possible.
	 */
	if (cp->dpgno == PGNO_INVALID)
		cp->indx = indx;
	else
		cp->dindx = indx;

	/*
	 * If the previous cursor record has been deleted, delete it.  The
	 * returned key isn't a deleted key, so clear the flag.
	 */
	if (F_ISSET(&copy, C_DELETED) &&
	    (ret = __bam_c_physdel(dbp, &copy, cp->page)) != 0)
		goto err;
	F_CLR(cp, C_DELETED | C_REPLACE);

	/* Release the previous lock, if any. */
	if (copy.lock != LOCK_INVALID)
		(void)__BT_TLPUT(dbp, copy.lock);

	/* Discard the pinned page. */
	ret = memp_fput(dbp->mpf, cp->page, 0);
	if (0) {
err:		if (cp->page != NULL)
			(void)memp_fput(dbp->mpf, cp->page, 0);
		if (cp->lock != LOCK_INVALID)
			(void)__BT_TLPUT(dbp, cp->lock);
		*cp = copy;
	}

	PUTHANDLE(dbp);
	return (ret);
}

/*
 * __bam_c_first --
 *	Return the first record.
 */
static int
__bam_c_first(dbp, cp)
	DB *dbp;
	CURSOR *cp;
{
	db_pgno_t pgno;
	int ret;

	/* Walk down the left-hand side of the tree. */
	for (pgno = PGNO_ROOT;;) {
		if ((ret =
		    __bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
			return (ret);
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			return (ret);

		/* If we find a leaf page, we're done. */
		if (ISLEAF(cp->page))
			break;

		pgno = GET_BINTERNAL(cp->page, 0)->pgno;
		DISCARD(dbp, cp);
	}

	cp->pgno = cp->page->pgno;
	cp->indx = 0;
	cp->dpgno = PGNO_INVALID;

	/* If it's an empty page or a deleted record, go to the next one. */
	if (NUM_ENT(cp->page) == 0 ||
	    B_DISSET(GET_BKEYDATA(cp->page, cp->indx + O_INDX)->type))
		if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
			return (ret);

	/* If it's a duplicate reference, go to the first entry. */
	if ((ret = __bam_ovfl_chk(dbp, cp, O_INDX, 0)) != 0)
		return (ret);

	/* If it's a deleted record, go to the next one. */
	if (cp->dpgno != PGNO_INVALID &&
	    B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
		if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
			return (ret);
	return (0);
}

/*
 * __bam_c_last --
 *	Return the last record.
 */
static int
__bam_c_last(dbp, cp)
	DB *dbp;
	CURSOR *cp;
{
	db_pgno_t pgno;
	int ret;

	/* Walk down the right-hand side of the tree. */
	for (pgno = PGNO_ROOT;;) {
		if ((ret =
		    __bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
			return (ret);
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			return (ret);

		/* If we find a leaf page, we're done. */
		if (ISLEAF(cp->page))
			break;

		pgno =
		    GET_BINTERNAL(cp->page, NUM_ENT(cp->page) - O_INDX)->pgno;
		DISCARD(dbp, cp);
	}

	cp->pgno = cp->page->pgno;
	cp->indx = NUM_ENT(cp->page) == 0 ? 0 : NUM_ENT(cp->page) - P_INDX;
	cp->dpgno = PGNO_INVALID;

	/* If it's an empty page or a deleted record, go to the previous one. */
	if (NUM_ENT(cp->page) == 0 ||
	    B_DISSET(GET_BKEYDATA(cp->page, cp->indx + O_INDX)->type))
		if ((ret = __bam_c_prev(dbp, cp)) != 0)
			return (ret);

	/* If it's a duplicate reference, go to the last entry. */
	if ((ret = __bam_ovfl_chk(dbp, cp, cp->indx + O_INDX, 1)) != 0)
		return (ret);

	/* If it's a deleted record, go to the previous one. */
	if (cp->dpgno != PGNO_INVALID &&
	    B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
		if ((ret = __bam_c_prev(dbp, cp)) != 0)
			return (ret);
	return (0);
}

/*
 * __bam_c_next --
 *	Move to the next record.
 */
static int
__bam_c_next(dbp, cp, initial_move)
	DB *dbp;
	CURSOR *cp;
	int initial_move;
{
	db_indx_t adjust, indx;
	db_pgno_t pgno;
	int ret;

	/*
	 * We're either moving through a page of duplicates or a btree leaf
	 * page.
	 */
	if (cp->dpgno == PGNO_INVALID) {
		adjust = dbp->type == DB_BTREE ? P_INDX : O_INDX;
		pgno = cp->pgno;
		indx = cp->indx;
	} else {
		adjust = O_INDX;
		pgno = cp->dpgno;
		indx = cp->dindx;
	}
	if (cp->page == NULL) {
		if ((ret =
		    __bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
			return (ret);
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			return (ret);
	}

	/*
	 * If at the end of the page, move to a subsequent page.
	 *
	 * !!!
	 * Check for >= NUM_ENT.  If we're here as the result of a search that
	 * landed us on NUM_ENT, we'll increment indx before we test.
	 *
	 * !!!
	 * This code handles empty pages and pages with only deleted entries.
	 */
	if (initial_move)
		indx += adjust;
	for (;;) {
		if (indx >= NUM_ENT(cp->page)) {
			pgno = cp->page->next_pgno;
			DISCARD(dbp, cp);

			/*
			 * If we're in a btree leaf page, we've reached the end
			 * of the tree.  If we've reached the end of a page of
			 * duplicates, continue from the btree leaf page where
			 * we found this page of duplicates.
			 */
			if (pgno == PGNO_INVALID) {
				/* If in a btree leaf page, it's EOF. */
				if (cp->dpgno == PGNO_INVALID)
					return (DB_NOTFOUND);

				/* Continue from the last btree leaf page. */
				cp->dpgno = PGNO_INVALID;

				adjust = P_INDX;
				pgno = cp->pgno;
				indx = cp->indx + P_INDX;
			} else
				indx = 0;

			if ((ret = __bam_lget(dbp,
			    0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
				return (ret);
			if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
				return (ret);
			continue;
		}

		/* Ignore deleted records. */
		if (dbp->type == DB_BTREE &&
		    ((cp->dpgno == PGNO_INVALID &&
		    B_DISSET(GET_BKEYDATA(cp->page, indx + O_INDX)->type)) ||
		    (cp->dpgno != PGNO_INVALID &&
		    B_DISSET(GET_BKEYDATA(cp->page, indx)->type)))) {
			indx += adjust;
			continue;
		}

		/*
		 * If we're not in a duplicates page, check to see if we've
		 * found a page of duplicates, in which case we move to the
		 * first entry.
		 */
		if (cp->dpgno == PGNO_INVALID) {
			cp->pgno = cp->page->pgno;
			cp->indx = indx;

			if ((ret =
			    __bam_ovfl_chk(dbp, cp, indx + O_INDX, 0)) != 0)
				return (ret);
			if (cp->dpgno != PGNO_INVALID) {
				indx = cp->dindx;
				adjust = O_INDX;
				continue;
			}
		} else {
			cp->dpgno = cp->page->pgno;
			cp->dindx = indx;
		}
		break;
	}
	return (0);
}

/*
 * __bam_c_prev --
 *	Move to the previous record.
 */
static int
__bam_c_prev(dbp, cp)
	DB *dbp;
	CURSOR *cp;
{
	db_indx_t indx, adjust;
	db_pgno_t pgno;
	int ret, set_indx;

	/*
	 * We're either moving through a page of duplicates or a btree leaf
	 * page.
	 */
	if (cp->dpgno == PGNO_INVALID) {
		adjust = dbp->type == DB_BTREE ? P_INDX : O_INDX;
		pgno = cp->pgno;
		indx = cp->indx;
	} else {
		adjust = O_INDX;
		pgno = cp->dpgno;
		indx = cp->dindx;
	}
	if (cp->page == NULL) {
		if ((ret =
		    __bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
			return (ret);
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			return (ret);
	}

	/*
	 * If at the beginning of the page, move to any previous one.
	 *
	 * !!!
	 * This code handles empty pages and pages with only deleted entries.
	 */
	for (;;) {
		if (indx == 0) {
			pgno = cp->page->prev_pgno;
			DISCARD(dbp, cp);

			/*
			 * If we're in a btree leaf page, we've reached the
			 * beginning of the tree.  If we've reached the first
			 * of a page of duplicates, continue from the btree
			 * leaf page where we found this page of duplicates.
			 */
			if (pgno == PGNO_INVALID) {
				/* If in a btree leaf page, it's SOF. */
				if (cp->dpgno == PGNO_INVALID)
					return (DB_NOTFOUND);

				/* Continue from the last btree leaf page. */
				cp->dpgno = PGNO_INVALID;

				adjust = P_INDX;
				pgno = cp->pgno;
				indx = cp->indx;
				set_indx = 0;
			} else
				set_indx = 1;

			if ((ret = __bam_lget(dbp,
			    0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
				return (ret);
			if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
				return (ret);

			if (set_indx)
				indx = NUM_ENT(cp->page);
			if (indx == 0)
				continue;
		}

		/* Ignore deleted records. */
		indx -= adjust;
		if (dbp->type == DB_BTREE &&
		    ((cp->dpgno == PGNO_INVALID &&
		    B_DISSET(GET_BKEYDATA(cp->page, indx + O_INDX)->type)) ||
		    (cp->dpgno != PGNO_INVALID &&
		    B_DISSET(GET_BKEYDATA(cp->page, indx)->type))))
			continue;

		/*
		 * If we're not in a duplicates page, check to see if we've
		 * found a page of duplicates, in which case we move to the
		 * last entry.
		 */
		if (cp->dpgno == PGNO_INVALID) {
			cp->pgno = cp->page->pgno;
			cp->indx = indx;

			if ((ret =
			    __bam_ovfl_chk(dbp, cp, indx + O_INDX, 1)) != 0)
				return (ret);
			if (cp->dpgno != PGNO_INVALID) {
				indx = cp->dindx + O_INDX;
				adjust = O_INDX;
				continue;
			}
		} else {
			cp->dpgno = cp->page->pgno;
			cp->dindx = indx;
		}
		break;
	}
	return (0);
}

/*
 * __bam_c_search --
 *	Move to a specified record.
 */
static int
__bam_c_search(dbp, cp, key, flags, isrecno, exactp)
	DB *dbp;
	CURSOR *cp;
	const DBT *key;
	u_int flags;
	int isrecno, *exactp;
{
	BTREE *t;
	db_recno_t recno;
	int needexact, ret;

	t = dbp->internal;
	needexact = *exactp;

	/*
	 * Find any matching record; the search function pins the page.  Make
	 * sure it's a valid key (__bam_search may return an index just past
	 * the end of a page) and return it.
	 */
	if (isrecno) {
		if ((ret = __ram_getno(dbp, key, &recno, 0)) != 0)
			return (ret);
		ret = __bam_rsearch(dbp, &recno, flags, 1, exactp);
	} else
		ret = __bam_search(dbp, key, flags, 1, NULL, exactp);
	if (ret != 0)
		return (ret);

	cp->page = t->bt_csp->page;
	cp->pgno = cp->page->pgno;
	cp->indx = t->bt_csp->indx;
	cp->lock = t->bt_csp->lock;
	cp->dpgno = PGNO_INVALID;

	/*
	 * If we have an exact match, make sure that we're not looking at a
	 * chain of duplicates -- if so, move to an entry in that chain.
	 */
	if (*exactp) {
		if ((ret = __bam_ovfl_chk(dbp,
		    cp, cp->indx + O_INDX, LF_ISSET(S_DUPLAST))) != 0)
			return (ret);
	} else
		if (needexact)
			return (DB_NOTFOUND);

	/* If past the end of a page, find the next entry. */
	if (cp->indx == NUM_ENT(cp->page) &&
	    (ret = __bam_c_next(dbp, cp, 0)) != 0)
		return (ret);

	/* If it's a deleted record, go to the next or previous one. */
	if (cp->dpgno != PGNO_INVALID &&
	    B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
		if (flags == S_KEYLAST) {
			if ((ret = __bam_c_prev(dbp, cp)) != 0)
				return (ret);
		} else
			if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
				return (ret);
	return (0);
}

/*
 * __bam_ovfl_chk --
 *	Check for an overflow record, and if found, move to the correct
 *	record.
 *
 * PUBLIC: int __bam_ovfl_chk __P((DB *, CURSOR *, u_int32_t, int));
 */
int
__bam_ovfl_chk(dbp, cp, indx, to_end)
	DB *dbp;
	CURSOR *cp;
	u_int32_t indx;
	int to_end;
{
	BOVERFLOW *bo;
	db_pgno_t pgno;
	int ret;

	/* Check for an overflow entry. */
	bo = GET_BOVERFLOW(cp->page, indx);
	if (B_TYPE(bo->type) != B_DUPLICATE)
		return (0);

	/*
	 * If we find one, go to the duplicates page, and optionally move
	 * to the last record on that page.
	 *
	 * XXX
	 * We don't lock duplicates pages, we've already got the correct
	 * lock on the main page.
	 */
	pgno = bo->pgno;
	if ((ret = memp_fput(dbp->mpf, cp->page, 0)) != 0)
		return (ret);
	cp->page = NULL;
	if (to_end) {
		if ((ret = __db_dend(dbp, pgno, &cp->page)) != 0)
			return (ret);
		indx = NUM_ENT(cp->page) - O_INDX;
	} else {
		if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
			return (ret);
		indx = 0;
	}

	/* Update the duplicate entry in the cursor. */
	cp->dpgno = cp->page->pgno;
	cp->dindx = indx;

	return (0);
}

#ifdef DEBUG
/*
 * __bam_cprint --
 *	Display the current btree cursor list.
 */
int
__bam_cprint(dbp)
	DB *dbp;
{
	CURSOR *cp;
	DBC *dbc;

	DB_THREAD_LOCK(dbp);
	for (dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		fprintf(stderr,
		    "%#0x: page: %lu index: %lu dpage %lu dindex: %lu",
		    (u_int)cp, (u_long)cp->pgno, (u_long)cp->indx,
		    (u_long)cp->dpgno, (u_long)cp->dindx);
		if (F_ISSET(cp, C_DELETED))
			fprintf(stderr, "(deleted)");
		fprintf(stderr, "\n");
	}
	DB_THREAD_UNLOCK(dbp);
	return (0);
}
#endif /* DEBUG */

/*
 * __bam_ca_delete --
 * 	Check if any of the cursors refer to the item we are about to delete.
 *	We'll return the number of cursors that refer to the item in question.
 *	If a cursor does refer to the item, then we set its deleted bit.
 *
 * PUBLIC: int __bam_ca_delete __P((DB *, db_pgno_t, u_int32_t, CURSOR *));
 */
int
__bam_ca_delete(dbp, pgno, indx, curs)
	DB *dbp;
	db_pgno_t pgno;
	u_int32_t indx;
	CURSOR *curs;
{
	DBC *dbc;
	CURSOR *cp;
	int count;

	/*
	 * Adjust the cursors.  We don't have to review the cursors for any
	 * process other than the current one, because we have the page write
	 * locked at this point, and any other process had better be using a
	 * different locker ID, meaning that only cursors in our process can
	 * be on the page.
	 *
	 * It's possible for multiple cursors within the thread to have write
	 * locks on the same page, but, cursors within a thread must be single
	 * threaded, so all we're locking here is the cursor linked list.
	 *
	 * indx refers to the first of what might be a duplicate set.  The
	 * cursor passed in is the one initiating the delete, so we don't
	 * want to count it.
	 */
	DB_THREAD_LOCK(dbp);
	for (count = 0, dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		if ((curs != cp &&
		    cp->pgno == pgno && cp->indx == indx) ||
		    (cp->dpgno == pgno && cp->dindx == indx)) {
			++count;
			F_SET(cp, C_DELETED);
		}
	}
	DB_THREAD_UNLOCK(dbp);
	return (count);
}

/*
 * __bam_ca_di --
 *	Adjust the cursors during a delete or insert.
 *
 * PUBLIC: void __bam_ca_di __P((DB *, db_pgno_t, u_int32_t, int));
 */
void
__bam_ca_di(dbp, pgno, indx, value)
	DB *dbp;
	db_pgno_t pgno;
	u_int32_t indx;
	int value;
{
	CURSOR *cp;
	DBC *dbc;

	/* Recno is responsible for its own adjustments. */
	if (dbp->type == DB_RECNO)
		return;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 */
	DB_THREAD_LOCK(dbp);
	for (dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		if (cp->pgno == pgno && cp->indx >= indx)
			cp->indx += value;
		if (cp->dpgno == pgno && cp->dindx >= indx)
			cp->dindx += value;
	}
	DB_THREAD_UNLOCK(dbp);
}

/*
 * __bam_ca_dup --
 *	Adjust the cursors when moving data items to a duplicates page.
 *
 * PUBLIC: void __bam_ca_dup __P((DB *,
 * PUBLIC:    db_pgno_t, u_int32_t, u_int32_t, db_pgno_t, u_int32_t));
 */
void
__bam_ca_dup(dbp, fpgno, first, fi, tpgno, ti)
	DB *dbp;
	db_pgno_t fpgno, tpgno;
	u_int32_t first, fi, ti;
{
	CURSOR *cp;
	DBC *dbc;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * No need to test duplicates, this only gets called when moving
	 * leaf page data items onto a duplicates page.
	 */
	DB_THREAD_LOCK(dbp);
	for (dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		/*
		 * Ignore matching entries that have already been moved,
		 * we move from the same location on the leaf page more
		 * than once.
		 */
		if (cp->dpgno == PGNO_INVALID &&
		    cp->pgno == fpgno && cp->indx == fi) {
			cp->indx = first;
			cp->dpgno = tpgno;
			cp->dindx = ti;
		}
	}
	DB_THREAD_UNLOCK(dbp);
}

/*
 * __bam_ca_move --
 *	Adjust the cursors when moving data items to another page.
 *
 * PUBLIC: void __bam_ca_move __P((DB *, BTREE *, db_pgno_t, db_pgno_t));
 */
void
__bam_ca_move(dbp, t, fpgno, tpgno)
	DB *dbp;
	BTREE *t;
	db_pgno_t fpgno, tpgno;
{
	CURSOR *cp;
	DBC *dbc;

	/* Recno is responsible for its own adjustments. */
	if (dbp->type == DB_RECNO)
		return;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * No need to test duplicates, this only gets called when copying
	 * over the root page with a leaf or internal page.
	 */
	DB_THREAD_LOCK(dbp);
	for (dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		if (cp->pgno == fpgno)
			cp->pgno = tpgno;
	}
	DB_THREAD_UNLOCK(dbp);
}

/*
 * __bam_ca_replace --
 * 	Check if any of the cursors refer to the item we are about to replace.
 *	If so, their flags should be changed from deleted to replaced.
 *
 * PUBLIC: void __bam_ca_replace
 * PUBLIC:    __P((DB *, db_pgno_t, u_int32_t, ca_replace_arg));
 */
void
__bam_ca_replace(dbp, pgno, indx, pass)
	DB *dbp;
	db_pgno_t pgno;
	u_int32_t indx;
	ca_replace_arg pass;
{
	CURSOR *cp;
	DBC *dbc;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * Find any cursors that have logically deleted a record we're about
	 * to overwrite.
	 *
	 * Pass == REPLACE_SETUP:
	 *	Set C_REPLACE_SETUP so we can find the cursors again.
	 *
	 * Pass == REPLACE_SUCCESS:
	 *	Clear C_DELETED and C_REPLACE_SETUP, set C_REPLACE, the
	 *	overwrite was successful.
	 *
	 * Pass == REPLACE_FAILED:
	 *	Clear C_REPLACE_SETUP, the overwrite failed.
	 *
	 * For REPLACE_SUCCESS and REPLACE_FAILED, we reset the indx value
	 * for the cursor as it may have been changed by other cursor update
	 * routines as the item was deleted/inserted.
	 */
	DB_THREAD_LOCK(dbp);
	switch (pass) {
	case REPLACE_SETUP:			/* Setup. */
		for (dbc = TAILQ_FIRST(&dbp->curs_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			cp = (CURSOR *)dbc->internal;
			if ((cp->pgno == pgno && cp->indx == indx) ||
			    (cp->dpgno == pgno && cp->dindx == indx))
				F_SET(cp, C_REPLACE_SETUP);
		}
		break;
	case REPLACE_SUCCESS:			/* Overwrite succeeded. */
		for (dbc = TAILQ_FIRST(&dbp->curs_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			cp = (CURSOR *)dbc->internal;
			if (F_ISSET(cp, C_REPLACE_SETUP)) {
				if (cp->dpgno == pgno)
					cp->dindx = indx;
				if (cp->pgno == pgno)
					cp->indx = indx;
				F_SET(cp, C_REPLACE);
				F_CLR(cp, C_DELETED | C_REPLACE_SETUP);
			}
		}
		break;
	case REPLACE_FAILED:			/* Overwrite failed. */
		for (dbc = TAILQ_FIRST(&dbp->curs_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			cp = (CURSOR *)dbc->internal;
			if (F_ISSET(cp, C_REPLACE_SETUP)) {
				if (cp->dpgno == pgno)
					cp->dindx = indx;
				if (cp->pgno == pgno)
					cp->indx = indx;
				F_CLR(cp, C_REPLACE_SETUP);
			}
		}
		break;
	}
	DB_THREAD_UNLOCK(dbp);
}

/*
 * __bam_ca_split --
 *	Adjust the cursors when splitting a page.
 *
 * PUBLIC: void __bam_ca_split __P((DB *,
 * PUBLIC:    db_pgno_t, db_pgno_t, db_pgno_t, u_int32_t, int));
 */
void
__bam_ca_split(dbp, ppgno, lpgno, rpgno, split_indx, cleft)
	DB *dbp;
	db_pgno_t ppgno, lpgno, rpgno;
	u_int32_t split_indx;
	int cleft;
{
	DBC *dbc;
	CURSOR *cp;

	/* Recno is responsible for its own adjustments. */
	if (dbp->type == DB_RECNO)
		return;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * If splitting the page that a cursor was on, the cursor has to be
	 * adjusted to point to the same record as before the split.  Most
	 * of the time we don't adjust pointers to the left page, because
	 * we're going to copy its contents back over the original page.  If
	 * the cursor is on the right page, it is decremented by the number of
	 * records split to the left page.
	 */
	DB_THREAD_LOCK(dbp);
	for (dbc = TAILQ_FIRST(&dbp->curs_queue);
	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
		cp = (CURSOR *)dbc->internal;
		if (cp->pgno == ppgno)
			if (cp->indx < split_indx) {
				if (cleft)
					cp->pgno = lpgno;
			} else {
				cp->pgno = rpgno;
				cp->indx -= split_indx;
			}
		if (cp->dpgno == ppgno)
			if (cp->dindx < split_indx) {
				if (cleft)
					cp->dpgno = lpgno;
			} else {
				cp->dpgno = rpgno;
				cp->dindx -= split_indx;
			}
	}
	DB_THREAD_UNLOCK(dbp);
}

/*
 * __bam_c_physdel --
 *	Actually do the cursor deletion.
 */
static int
__bam_c_physdel(dbp, cp, h)
	DB *dbp;
	CURSOR *cp;
	PAGE *h;
{
	BOVERFLOW bo;
	BTREE *t;
	DBT dbt;
	DB_LOCK lock;
	db_indx_t indx;
	db_pgno_t pgno, next_pgno, prev_pgno;
	int local, normal, ret;

	t = dbp->internal;
	ret = 0;

	/* Figure out what we're deleting. */
	if (cp->dpgno == PGNO_INVALID) {
		pgno = cp->pgno;
		indx = cp->indx;
	} else {
		pgno = cp->dpgno;
		indx = cp->dindx;
	}

	/*
	 * If the item is referenced by another cursor, leave it up to that
	 * cursor to do the delete.
	 */
	if (__bam_ca_delete(dbp, pgno, indx, cp) != 0)
		return (0);

	/*
	 * If we don't already have the page locked, get it and delete the
	 * items.
	 */
	if ((h == NULL || h->pgno != pgno)) {
		if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &lock)) != 0)
			return (ret);
		if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
			return (ret);
		local = 1;
	} else
		local = 0;

	/*
	 * If we're deleting a duplicate entry and there are other duplicate
	 * entries remaining, call the common code to do the work and fix up
	 * the parent page as necessary.  Otherwise, do a normal btree delete.
	 *
	 * There are 5 possible cases:
	 *
	 * 1. It's not a duplicate item: do a normal btree delete.
	 * 2. It's a duplicate item:
	 *	2a: We delete an item from a page of duplicates, but there are
	 *	    more items on the page.
	 *      2b: We delete the last item from a page of duplicates, deleting
	 *	    the last duplicate.
	 *      2c: We delete the last item from a page of duplicates, but there
	 *	    is a previous page of duplicates.
	 *      2d: We delete the last item from a page of duplicates, but there
	 *	    is a following page of duplicates.
	 *
	 * In the case of:
	 *
	 *  1: There's nothing further to do.
	 * 2a: There's nothing further to do.
	 * 2b: Do the normal btree delete instead of a duplicate delete, as
	 *     that deletes both the duplicate chain and the parent page's
	 *     entry.
	 * 2c: There's nothing further to do.
	 * 2d: Delete the duplicate, and update the parent page's entry.
	 */
	if (TYPE(h) == P_DUPLICATE) {
		pgno = PGNO(h);
		prev_pgno = PREV_PGNO(h);
		next_pgno = NEXT_PGNO(h);

		if (NUM_ENT(h) == 1 &&
		    prev_pgno == PGNO_INVALID && next_pgno == PGNO_INVALID)
			normal = 1;
		else {
			normal = 0;

			/* Delete the duplicate. */
			if ((ret = __db_drem(dbp, &h, indx, __bam_free)) != 0)
				goto err;

			/*
			 * 2a: h != NULL, h->pgno == pgno
			 * 2b: We don't reach this clause, as the above test
			 *     was true.
			 * 2c: h == NULL, prev_pgno != PGNO_INVALID
			 * 2d: h != NULL, next_pgno != PGNO_INVALID
			 *
			 * Test for 2a and 2c: if we didn't empty the current
			 * page or there was a previous page of duplicates, we
			 * don't need to touch the parent page.
			 */
			if ((h != NULL && pgno == h->pgno) ||
			    prev_pgno != PGNO_INVALID)
				goto done;
		}

		/* Release any page we're holding and its lock. */
		if (local) {
			if (h != NULL)
				(void)memp_fput(dbp->mpf, h, 0);
			(void)__BT_TLPUT(dbp, lock);
			local = 0;
		}

		/* Acquire the parent page. */
		if ((ret =
		    __bam_lget(dbp, 0, cp->pgno, DB_LOCK_WRITE, &lock)) != 0)
			goto err;
		if ((ret = __bam_pget(dbp, &h, &cp->pgno, 0)) != 0) {
			(void)__BT_TLPUT(dbp, lock);
			goto err;
		}
		local = 1;

		/* Switch to the parent page's entry. */
		indx = cp->indx;
		if (normal)
			goto btd;

		/*
		 * Copy, delete, update, add-back the parent page's data entry.
		 *
		 * XXX
		 * This may be a performance/logging problem.  We should add a
		 * log message which simply logs/updates a random set of bytes
		 * on a page, and use it instead of doing a delete/add pair.
		 */
		indx += O_INDX;
		bo = *GET_BOVERFLOW(h, indx);
		(void)__db_ditem(dbp, h, indx, BOVERFLOW_SIZE);
		bo.pgno = next_pgno;
		memset(&dbt, 0, sizeof(dbt));
		dbt.data = &bo;
		dbt.size = BOVERFLOW_SIZE;
		(void)__db_pitem(dbp, h, indx, BOVERFLOW_SIZE, &dbt, NULL);
		(void)memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY);
		goto done;
	}

	/* Otherwise, do a normal btree delete. */
btd:	if ((ret = __bam_ditem(dbp, h, indx)) != 0)
		goto err;
	if ((ret = __bam_ditem(dbp, h, indx)) != 0)
		goto err;

	/*
	 * If the page is empty, delete it.  To delete a leaf page we need a
	 * copy of a key from the page.  We use the first one that was there,
	 * since it's the last key that the page held.  We malloc the page
	 * information instead of using the return key/data memory because
	 * we've already set them -- the reason that we've already set them
	 * is because we're (potentially) about to do a reverse split, which
	 * would make our saved page information useless.
	 *
	 * XXX
	 * The following operations to delete a page might deadlock.  I think
	 * that's OK.  The problem is if we're deleting an item because we're
	 * closing cursors because we've already deadlocked and want to call
	 * txn_abort().  If we fail due to deadlock, we'll leave an locked
	 * empty page in the tree, which won't be empty long because we're
	 * going to undo the delete.
	 */
	if (NUM_ENT(h) == 0 && h->pgno != PGNO_ROOT) {
		memset(&dbt, 0, sizeof(DBT));
		dbt.flags = DB_DBT_MALLOC | DB_DBT_INTERNAL;
		if ((ret = __db_ret(dbp, h, 0, &dbt, NULL, NULL)) != 0)
			goto err;

		if (local) {
			(void)memp_fput(dbp->mpf, h, 0);
			(void)__BT_TLPUT(dbp, lock);
			local = 0;
		}

		ret = __bam_dpage(dbp, &dbt);
		__db_free(dbt.data);
	}

err:
done:	if (local) {
		(void)memp_fput(dbp->mpf, h, 0);
		(void)__BT_TLPUT(dbp, lock);
	}

	if (ret == 0)
		++t->lstat.bt_deleted;
	return (ret);
}