summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_alloc_btree.c
blob: 974a412ebc8a34d571f91e3f895cae0afccca12a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_error.h"

/*
 * Prototypes for internal functions.
 */

STATIC void xfs_alloc_log_block(xfs_trans_t *, xfs_buf_t *, int);
STATIC void xfs_alloc_log_keys(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC void xfs_alloc_log_ptrs(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC void xfs_alloc_log_recs(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC int xfs_alloc_newroot(xfs_btree_cur_t *, int *);
STATIC int xfs_alloc_split(xfs_btree_cur_t *, int, xfs_agblock_t *,
		xfs_alloc_key_t *, xfs_btree_cur_t **, int *);

/*
 * Internal functions.
 */

/*
 * Single level of the xfs_alloc_delete record deletion routine.
 * Delete record pointed to by cur/level.
 * Remove the record from its block then rebalance the tree.
 * Return 0 for error, 1 for done, 2 to go on to the next level.
 */
STATIC int				/* error */
xfs_alloc_delrec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level removing record from */
	int			*stat)	/* fail/done/go-on */
{
	xfs_agf_t		*agf;	/* allocation group freelist header */
	xfs_alloc_block_t	*block;	/* btree block record/key lives in */
	xfs_agblock_t		bno;	/* btree block number */
	xfs_buf_t		*bp;	/* buffer for block */
	int			error;	/* error return value */
	int			i;	/* loop index */
	xfs_alloc_key_t		key;	/* kp points here if block is level 0 */
	xfs_agblock_t		lbno;	/* left block's block number */
	xfs_buf_t		*lbp;	/* left block's buffer pointer */
	xfs_alloc_block_t	*left;	/* left btree block */
	xfs_alloc_key_t		*lkp=NULL;	/* left block key pointer */
	xfs_alloc_ptr_t		*lpp=NULL;	/* left block address pointer */
	int			lrecs=0;	/* number of records in left block */
	xfs_alloc_rec_t		*lrp;	/* left block record pointer */
	xfs_mount_t		*mp;	/* mount structure */
	int			ptr;	/* index in btree block for this rec */
	xfs_agblock_t		rbno;	/* right block's block number */
	xfs_buf_t		*rbp;	/* right block's buffer pointer */
	xfs_alloc_block_t	*right;	/* right btree block */
	xfs_alloc_key_t		*rkp;	/* right block key pointer */
	xfs_alloc_ptr_t		*rpp;	/* right block address pointer */
	int			rrecs=0;	/* number of records in right block */
	int			numrecs;
	xfs_alloc_rec_t		*rrp;	/* right block record pointer */
	xfs_btree_cur_t		*tcur;	/* temporary btree cursor */

	/*
	 * Get the index of the entry being deleted, check for nothing there.
	 */
	ptr = cur->bc_ptrs[level];
	if (ptr == 0) {
		*stat = 0;
		return 0;
	}
	/*
	 * Get the buffer & block containing the record or key/ptr.
	 */
	bp = cur->bc_bufs[level];
	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, level, bp)))
		return error;
#endif
	/*
	 * Fail if we're off the end of the block.
	 */
	numrecs = be16_to_cpu(block->bb_numrecs);
	if (ptr > numrecs) {
		*stat = 0;
		return 0;
	}
	XFS_STATS_INC(xs_abt_delrec);
	/*
	 * It's a nonleaf.  Excise the key and ptr being deleted, by
	 * sliding the entries past them down one.
	 * Log the changed areas of the block.
	 */
	if (level > 0) {
		lkp = XFS_ALLOC_KEY_ADDR(block, 1, cur);
		lpp = XFS_ALLOC_PTR_ADDR(block, 1, cur);
#ifdef DEBUG
		for (i = ptr; i < numrecs; i++) {
			if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(lpp[i]), level)))
				return error;
		}
#endif
		if (ptr < numrecs) {
			memmove(&lkp[ptr - 1], &lkp[ptr],
				(numrecs - ptr) * sizeof(*lkp));
			memmove(&lpp[ptr - 1], &lpp[ptr],
				(numrecs - ptr) * sizeof(*lpp));
			xfs_alloc_log_ptrs(cur, bp, ptr, numrecs - 1);
			xfs_alloc_log_keys(cur, bp, ptr, numrecs - 1);
		}
	}
	/*
	 * It's a leaf.  Excise the record being deleted, by sliding the
	 * entries past it down one.  Log the changed areas of the block.
	 */
	else {
		lrp = XFS_ALLOC_REC_ADDR(block, 1, cur);
		if (ptr < numrecs) {
			memmove(&lrp[ptr - 1], &lrp[ptr],
				(numrecs - ptr) * sizeof(*lrp));
			xfs_alloc_log_recs(cur, bp, ptr, numrecs - 1);
		}
		/*
		 * If it's the first record in the block, we'll need a key
		 * structure to pass up to the next level (updkey).
		 */
		if (ptr == 1) {
			key.ar_startblock = lrp->ar_startblock;
			key.ar_blockcount = lrp->ar_blockcount;
			lkp = &key;
		}
	}
	/*
	 * Decrement and log the number of entries in the block.
	 */
	numrecs--;
	block->bb_numrecs = cpu_to_be16(numrecs);
	xfs_alloc_log_block(cur->bc_tp, bp, XFS_BB_NUMRECS);
	/*
	 * See if the longest free extent in the allocation group was
	 * changed by this operation.  True if it's the by-size btree, and
	 * this is the leaf level, and there is no right sibling block,
	 * and this was the last record.
	 */
	agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
	mp = cur->bc_mp;

	if (level == 0 &&
	    cur->bc_btnum == XFS_BTNUM_CNT &&
	    be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK &&
	    ptr > numrecs) {
		ASSERT(ptr == numrecs + 1);
		/*
		 * There are still records in the block.  Grab the size
		 * from the last one.
		 */
		if (numrecs) {
			rrp = XFS_ALLOC_REC_ADDR(block, numrecs, cur);
			agf->agf_longest = rrp->ar_blockcount;
		}
		/*
		 * No free extents left.
		 */
		else
			agf->agf_longest = 0;
		mp->m_perag[be32_to_cpu(agf->agf_seqno)].pagf_longest =
			be32_to_cpu(agf->agf_longest);
		xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
			XFS_AGF_LONGEST);
	}
	/*
	 * Is this the root level?  If so, we're almost done.
	 */
	if (level == cur->bc_nlevels - 1) {
		/*
		 * If this is the root level,
		 * and there's only one entry left,
		 * and it's NOT the leaf level,
		 * then we can get rid of this level.
		 */
		if (numrecs == 1 && level > 0) {
			/*
			 * lpp is still set to the first pointer in the block.
			 * Make it the new root of the btree.
			 */
			bno = be32_to_cpu(agf->agf_roots[cur->bc_btnum]);
			agf->agf_roots[cur->bc_btnum] = *lpp;
			be32_add_cpu(&agf->agf_levels[cur->bc_btnum], -1);
			mp->m_perag[be32_to_cpu(agf->agf_seqno)].pagf_levels[cur->bc_btnum]--;
			/*
			 * Put this buffer/block on the ag's freelist.
			 */
			error = xfs_alloc_put_freelist(cur->bc_tp,
					cur->bc_private.a.agbp, NULL, bno, 1);
			if (error)
				return error;
			/*
			 * Since blocks move to the free list without the
			 * coordination used in xfs_bmap_finish, we can't allow
			 * block to be available for reallocation and
			 * non-transaction writing (user data) until we know
			 * that the transaction that moved it to the free list
			 * is permanently on disk. We track the blocks by
			 * declaring these blocks as "busy"; the busy list is
			 * maintained on a per-ag basis and each transaction
			 * records which entries should be removed when the
			 * iclog commits to disk. If a busy block is
			 * allocated, the iclog is pushed up to the LSN
			 * that freed the block.
			 */
			xfs_alloc_mark_busy(cur->bc_tp,
				be32_to_cpu(agf->agf_seqno), bno, 1);

			xfs_trans_agbtree_delta(cur->bc_tp, -1);
			xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
				XFS_AGF_ROOTS | XFS_AGF_LEVELS);
			/*
			 * Update the cursor so there's one fewer level.
			 */
			xfs_btree_setbuf(cur, level, NULL);
			cur->bc_nlevels--;
		} else if (level > 0 &&
			   (error = xfs_btree_decrement(cur, level, &i)))
			return error;
		*stat = 1;
		return 0;
	}
	/*
	 * If we deleted the leftmost entry in the block, update the
	 * key values above us in the tree.
	 */
	if (ptr == 1 && (error = xfs_btree_updkey(cur, (union xfs_btree_key *)lkp, level + 1)))
		return error;
	/*
	 * If the number of records remaining in the block is at least
	 * the minimum, we're done.
	 */
	if (numrecs >= XFS_ALLOC_BLOCK_MINRECS(level, cur)) {
		if (level > 0 && (error = xfs_btree_decrement(cur, level, &i)))
			return error;
		*stat = 1;
		return 0;
	}
	/*
	 * Otherwise, we have to move some records around to keep the
	 * tree balanced.  Look at the left and right sibling blocks to
	 * see if we can re-balance by moving only one record.
	 */
	rbno = be32_to_cpu(block->bb_rightsib);
	lbno = be32_to_cpu(block->bb_leftsib);
	bno = NULLAGBLOCK;
	ASSERT(rbno != NULLAGBLOCK || lbno != NULLAGBLOCK);
	/*
	 * Duplicate the cursor so our btree manipulations here won't
	 * disrupt the next level up.
	 */
	if ((error = xfs_btree_dup_cursor(cur, &tcur)))
		return error;
	/*
	 * If there's a right sibling, see if it's ok to shift an entry
	 * out of it.
	 */
	if (rbno != NULLAGBLOCK) {
		/*
		 * Move the temp cursor to the last entry in the next block.
		 * Actually any entry but the first would suffice.
		 */
		i = xfs_btree_lastrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		if ((error = xfs_btree_increment(tcur, level, &i)))
			goto error0;
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		i = xfs_btree_lastrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		/*
		 * Grab a pointer to the block.
		 */
		rbp = tcur->bc_bufs[level];
		right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
#ifdef DEBUG
		if ((error = xfs_btree_check_sblock(cur, right, level, rbp)))
			goto error0;
#endif
		/*
		 * Grab the current block number, for future use.
		 */
		bno = be32_to_cpu(right->bb_leftsib);
		/*
		 * If right block is full enough so that removing one entry
		 * won't make it too empty, and left-shifting an entry out
		 * of right to us works, we're done.
		 */
		if (be16_to_cpu(right->bb_numrecs) - 1 >=
		     XFS_ALLOC_BLOCK_MINRECS(level, cur)) {
			if ((error = xfs_btree_lshift(tcur, level, &i)))
				goto error0;
			if (i) {
				ASSERT(be16_to_cpu(block->bb_numrecs) >=
				       XFS_ALLOC_BLOCK_MINRECS(level, cur));
				xfs_btree_del_cursor(tcur,
						     XFS_BTREE_NOERROR);
				if (level > 0 &&
				    (error = xfs_btree_decrement(cur, level,
					    &i)))
					return error;
				*stat = 1;
				return 0;
			}
		}
		/*
		 * Otherwise, grab the number of records in right for
		 * future reference, and fix up the temp cursor to point
		 * to our block again (last record).
		 */
		rrecs = be16_to_cpu(right->bb_numrecs);
		if (lbno != NULLAGBLOCK) {
			i = xfs_btree_firstrec(tcur, level);
			XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
			if ((error = xfs_btree_decrement(tcur, level, &i)))
				goto error0;
			XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		}
	}
	/*
	 * If there's a left sibling, see if it's ok to shift an entry
	 * out of it.
	 */
	if (lbno != NULLAGBLOCK) {
		/*
		 * Move the temp cursor to the first entry in the
		 * previous block.
		 */
		i = xfs_btree_firstrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		if ((error = xfs_btree_decrement(tcur, level, &i)))
			goto error0;
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		xfs_btree_firstrec(tcur, level);
		/*
		 * Grab a pointer to the block.
		 */
		lbp = tcur->bc_bufs[level];
		left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
#ifdef DEBUG
		if ((error = xfs_btree_check_sblock(cur, left, level, lbp)))
			goto error0;
#endif
		/*
		 * Grab the current block number, for future use.
		 */
		bno = be32_to_cpu(left->bb_rightsib);
		/*
		 * If left block is full enough so that removing one entry
		 * won't make it too empty, and right-shifting an entry out
		 * of left to us works, we're done.
		 */
		if (be16_to_cpu(left->bb_numrecs) - 1 >=
		     XFS_ALLOC_BLOCK_MINRECS(level, cur)) {
			if ((error = xfs_btree_rshift(tcur, level, &i)))
				goto error0;
			if (i) {
				ASSERT(be16_to_cpu(block->bb_numrecs) >=
				       XFS_ALLOC_BLOCK_MINRECS(level, cur));
				xfs_btree_del_cursor(tcur,
						     XFS_BTREE_NOERROR);
				if (level == 0)
					cur->bc_ptrs[0]++;
				*stat = 1;
				return 0;
			}
		}
		/*
		 * Otherwise, grab the number of records in right for
		 * future reference.
		 */
		lrecs = be16_to_cpu(left->bb_numrecs);
	}
	/*
	 * Delete the temp cursor, we're done with it.
	 */
	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
	/*
	 * If here, we need to do a join to keep the tree balanced.
	 */
	ASSERT(bno != NULLAGBLOCK);
	/*
	 * See if we can join with the left neighbor block.
	 */
	if (lbno != NULLAGBLOCK &&
	    lrecs + numrecs <= XFS_ALLOC_BLOCK_MAXRECS(level, cur)) {
		/*
		 * Set "right" to be the starting block,
		 * "left" to be the left neighbor.
		 */
		rbno = bno;
		right = block;
		rrecs = be16_to_cpu(right->bb_numrecs);
		rbp = bp;
		if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
				cur->bc_private.a.agno, lbno, 0, &lbp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
		lrecs = be16_to_cpu(left->bb_numrecs);
		if ((error = xfs_btree_check_sblock(cur, left, level, lbp)))
			return error;
	}
	/*
	 * If that won't work, see if we can join with the right neighbor block.
	 */
	else if (rbno != NULLAGBLOCK &&
		 rrecs + numrecs <= XFS_ALLOC_BLOCK_MAXRECS(level, cur)) {
		/*
		 * Set "left" to be the starting block,
		 * "right" to be the right neighbor.
		 */
		lbno = bno;
		left = block;
		lrecs = be16_to_cpu(left->bb_numrecs);
		lbp = bp;
		if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
				cur->bc_private.a.agno, rbno, 0, &rbp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
		rrecs = be16_to_cpu(right->bb_numrecs);
		if ((error = xfs_btree_check_sblock(cur, right, level, rbp)))
			return error;
	}
	/*
	 * Otherwise, we can't fix the imbalance.
	 * Just return.  This is probably a logic error, but it's not fatal.
	 */
	else {
		if (level > 0 && (error = xfs_btree_decrement(cur, level, &i)))
			return error;
		*stat = 1;
		return 0;
	}
	/*
	 * We're now going to join "left" and "right" by moving all the stuff
	 * in "right" to "left" and deleting "right".
	 */
	if (level > 0) {
		/*
		 * It's a non-leaf.  Move keys and pointers.
		 */
		lkp = XFS_ALLOC_KEY_ADDR(left, lrecs + 1, cur);
		lpp = XFS_ALLOC_PTR_ADDR(left, lrecs + 1, cur);
		rkp = XFS_ALLOC_KEY_ADDR(right, 1, cur);
		rpp = XFS_ALLOC_PTR_ADDR(right, 1, cur);
#ifdef DEBUG
		for (i = 0; i < rrecs; i++) {
			if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(rpp[i]), level)))
				return error;
		}
#endif
		memcpy(lkp, rkp, rrecs * sizeof(*lkp));
		memcpy(lpp, rpp, rrecs * sizeof(*lpp));
		xfs_alloc_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
		xfs_alloc_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
	} else {
		/*
		 * It's a leaf.  Move records.
		 */
		lrp = XFS_ALLOC_REC_ADDR(left, lrecs + 1, cur);
		rrp = XFS_ALLOC_REC_ADDR(right, 1, cur);
		memcpy(lrp, rrp, rrecs * sizeof(*lrp));
		xfs_alloc_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
	}
	/*
	 * If we joined with the left neighbor, set the buffer in the
	 * cursor to the left block, and fix up the index.
	 */
	if (bp != lbp) {
		xfs_btree_setbuf(cur, level, lbp);
		cur->bc_ptrs[level] += lrecs;
	}
	/*
	 * If we joined with the right neighbor and there's a level above
	 * us, increment the cursor at that level.
	 */
	else if (level + 1 < cur->bc_nlevels &&
		 (error = xfs_btree_increment(cur, level + 1, &i)))
		return error;
	/*
	 * Fix up the number of records in the surviving block.
	 */
	lrecs += rrecs;
	left->bb_numrecs = cpu_to_be16(lrecs);
	/*
	 * Fix up the right block pointer in the surviving block, and log it.
	 */
	left->bb_rightsib = right->bb_rightsib;
	xfs_alloc_log_block(cur->bc_tp, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
	/*
	 * If there is a right sibling now, make it point to the
	 * remaining block.
	 */
	if (be32_to_cpu(left->bb_rightsib) != NULLAGBLOCK) {
		xfs_alloc_block_t	*rrblock;
		xfs_buf_t		*rrbp;

		if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
				cur->bc_private.a.agno, be32_to_cpu(left->bb_rightsib), 0,
				&rrbp, XFS_ALLOC_BTREE_REF)))
			return error;
		rrblock = XFS_BUF_TO_ALLOC_BLOCK(rrbp);
		if ((error = xfs_btree_check_sblock(cur, rrblock, level, rrbp)))
			return error;
		rrblock->bb_leftsib = cpu_to_be32(lbno);
		xfs_alloc_log_block(cur->bc_tp, rrbp, XFS_BB_LEFTSIB);
	}
	/*
	 * Free the deleting block by putting it on the freelist.
	 */
	error = xfs_alloc_put_freelist(cur->bc_tp,
					 cur->bc_private.a.agbp, NULL, rbno, 1);
	if (error)
		return error;
	/*
	 * Since blocks move to the free list without the coordination
	 * used in xfs_bmap_finish, we can't allow block to be available
	 * for reallocation and non-transaction writing (user data)
	 * until we know that the transaction that moved it to the free
	 * list is permanently on disk. We track the blocks by declaring
	 * these blocks as "busy"; the busy list is maintained on a
	 * per-ag basis and each transaction records which entries
	 * should be removed when the iclog commits to disk. If a
	 * busy block is allocated, the iclog is pushed up to the
	 * LSN that freed the block.
	 */
	xfs_alloc_mark_busy(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1);
	xfs_trans_agbtree_delta(cur->bc_tp, -1);

	/*
	 * Adjust the current level's cursor so that we're left referring
	 * to the right node, after we're done.
	 * If this leaves the ptr value 0 our caller will fix it up.
	 */
	if (level > 0)
		cur->bc_ptrs[level]--;
	/*
	 * Return value means the next level up has something to do.
	 */
	*stat = 2;
	return 0;

error0:
	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
	return error;
}

/*
 * Insert one record/level.  Return information to the caller
 * allowing the next level up to proceed if necessary.
 */
STATIC int				/* error */
xfs_alloc_insrec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level to insert record at */
	xfs_agblock_t		*bnop,	/* i/o: block number inserted */
	xfs_alloc_rec_t		*recp,	/* i/o: record data inserted */
	xfs_btree_cur_t		**curp,	/* output: new cursor replacing cur */
	int			*stat)	/* output: success/failure */
{
	xfs_agf_t		*agf;	/* allocation group freelist header */
	xfs_alloc_block_t	*block;	/* btree block record/key lives in */
	xfs_buf_t		*bp;	/* buffer for block */
	int			error;	/* error return value */
	int			i;	/* loop index */
	xfs_alloc_key_t		key;	/* key value being inserted */
	xfs_alloc_key_t		*kp;	/* pointer to btree keys */
	xfs_agblock_t		nbno;	/* block number of allocated block */
	xfs_btree_cur_t		*ncur;	/* new cursor to be used at next lvl */
	xfs_alloc_key_t		nkey;	/* new key value, from split */
	xfs_alloc_rec_t		nrec;	/* new record value, for caller */
	int			numrecs;
	int			optr;	/* old ptr value */
	xfs_alloc_ptr_t		*pp;	/* pointer to btree addresses */
	int			ptr;	/* index in btree block for this rec */
	xfs_alloc_rec_t		*rp;	/* pointer to btree records */

	ASSERT(be32_to_cpu(recp->ar_blockcount) > 0);

	/*
	 * GCC doesn't understand the (arguably complex) control flow in
	 * this function and complains about uninitialized structure fields
	 * without this.
	 */
	memset(&nrec, 0, sizeof(nrec));

	/*
	 * If we made it to the root level, allocate a new root block
	 * and we're done.
	 */
	if (level >= cur->bc_nlevels) {
		XFS_STATS_INC(xs_abt_insrec);
		if ((error = xfs_alloc_newroot(cur, &i)))
			return error;
		*bnop = NULLAGBLOCK;
		*stat = i;
		return 0;
	}
	/*
	 * Make a key out of the record data to be inserted, and save it.
	 */
	key.ar_startblock = recp->ar_startblock;
	key.ar_blockcount = recp->ar_blockcount;
	optr = ptr = cur->bc_ptrs[level];
	/*
	 * If we're off the left edge, return failure.
	 */
	if (ptr == 0) {
		*stat = 0;
		return 0;
	}
	XFS_STATS_INC(xs_abt_insrec);
	/*
	 * Get pointers to the btree buffer and block.
	 */
	bp = cur->bc_bufs[level];
	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
	numrecs = be16_to_cpu(block->bb_numrecs);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, level, bp)))
		return error;
	/*
	 * Check that the new entry is being inserted in the right place.
	 */
	if (ptr <= numrecs) {
		if (level == 0) {
			rp = XFS_ALLOC_REC_ADDR(block, ptr, cur);
			xfs_btree_check_rec(cur->bc_btnum, recp, rp);
		} else {
			kp = XFS_ALLOC_KEY_ADDR(block, ptr, cur);
			xfs_btree_check_key(cur->bc_btnum, &key, kp);
		}
	}
#endif
	nbno = NULLAGBLOCK;
	ncur = NULL;
	/*
	 * If the block is full, we can't insert the new entry until we
	 * make the block un-full.
	 */
	if (numrecs == XFS_ALLOC_BLOCK_MAXRECS(level, cur)) {
		/*
		 * First, try shifting an entry to the right neighbor.
		 */
		if ((error = xfs_btree_rshift(cur, level, &i)))
			return error;
		if (i) {
			/* nothing */
		}
		/*
		 * Next, try shifting an entry to the left neighbor.
		 */
		else {
			if ((error = xfs_btree_lshift(cur, level, &i)))
				return error;
			if (i)
				optr = ptr = cur->bc_ptrs[level];
			else {
				/*
				 * Next, try splitting the current block in
				 * half. If this works we have to re-set our
				 * variables because we could be in a
				 * different block now.
				 */
				if ((error = xfs_alloc_split(cur, level, &nbno,
						&nkey, &ncur, &i)))
					return error;
				if (i) {
					bp = cur->bc_bufs[level];
					block = XFS_BUF_TO_ALLOC_BLOCK(bp);
#ifdef DEBUG
					if ((error =
						xfs_btree_check_sblock(cur,
							block, level, bp)))
						return error;
#endif
					ptr = cur->bc_ptrs[level];
					nrec.ar_startblock = nkey.ar_startblock;
					nrec.ar_blockcount = nkey.ar_blockcount;
				}
				/*
				 * Otherwise the insert fails.
				 */
				else {
					*stat = 0;
					return 0;
				}
			}
		}
	}
	/*
	 * At this point we know there's room for our new entry in the block
	 * we're pointing at.
	 */
	numrecs = be16_to_cpu(block->bb_numrecs);
	if (level > 0) {
		/*
		 * It's a non-leaf entry.  Make a hole for the new data
		 * in the key and ptr regions of the block.
		 */
		kp = XFS_ALLOC_KEY_ADDR(block, 1, cur);
		pp = XFS_ALLOC_PTR_ADDR(block, 1, cur);
#ifdef DEBUG
		for (i = numrecs; i >= ptr; i--) {
			if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(pp[i - 1]), level)))
				return error;
		}
#endif
		memmove(&kp[ptr], &kp[ptr - 1],
			(numrecs - ptr + 1) * sizeof(*kp));
		memmove(&pp[ptr], &pp[ptr - 1],
			(numrecs - ptr + 1) * sizeof(*pp));
#ifdef DEBUG
		if ((error = xfs_btree_check_sptr(cur, *bnop, level)))
			return error;
#endif
		/*
		 * Now stuff the new data in, bump numrecs and log the new data.
		 */
		kp[ptr - 1] = key;
		pp[ptr - 1] = cpu_to_be32(*bnop);
		numrecs++;
		block->bb_numrecs = cpu_to_be16(numrecs);
		xfs_alloc_log_keys(cur, bp, ptr, numrecs);
		xfs_alloc_log_ptrs(cur, bp, ptr, numrecs);
#ifdef DEBUG
		if (ptr < numrecs)
			xfs_btree_check_key(cur->bc_btnum, kp + ptr - 1,
				kp + ptr);
#endif
	} else {
		/*
		 * It's a leaf entry.  Make a hole for the new record.
		 */
		rp = XFS_ALLOC_REC_ADDR(block, 1, cur);
		memmove(&rp[ptr], &rp[ptr - 1],
			(numrecs - ptr + 1) * sizeof(*rp));
		/*
		 * Now stuff the new record in, bump numrecs
		 * and log the new data.
		 */
		rp[ptr - 1] = *recp;
		numrecs++;
		block->bb_numrecs = cpu_to_be16(numrecs);
		xfs_alloc_log_recs(cur, bp, ptr, numrecs);
#ifdef DEBUG
		if (ptr < numrecs)
			xfs_btree_check_rec(cur->bc_btnum, rp + ptr - 1,
				rp + ptr);
#endif
	}
	/*
	 * Log the new number of records in the btree header.
	 */
	xfs_alloc_log_block(cur->bc_tp, bp, XFS_BB_NUMRECS);
	/*
	 * If we inserted at the start of a block, update the parents' keys.
	 */
	if (optr == 1 && (error = xfs_btree_updkey(cur, (union xfs_btree_key *)&key, level + 1)))
		return error;
	/*
	 * Look to see if the longest extent in the allocation group
	 * needs to be updated.
	 */

	agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
	if (level == 0 &&
	    cur->bc_btnum == XFS_BTNUM_CNT &&
	    be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK &&
	    be32_to_cpu(recp->ar_blockcount) > be32_to_cpu(agf->agf_longest)) {
		/*
		 * If this is a leaf in the by-size btree and there
		 * is no right sibling block and this block is bigger
		 * than the previous longest block, update it.
		 */
		agf->agf_longest = recp->ar_blockcount;
		cur->bc_mp->m_perag[be32_to_cpu(agf->agf_seqno)].pagf_longest
			= be32_to_cpu(recp->ar_blockcount);
		xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
			XFS_AGF_LONGEST);
	}
	/*
	 * Return the new block number, if any.
	 * If there is one, give back a record value and a cursor too.
	 */
	*bnop = nbno;
	if (nbno != NULLAGBLOCK) {
		*recp = nrec;
		*curp = ncur;
	}
	*stat = 1;
	return 0;
}

/*
 * Log header fields from a btree block.
 */
STATIC void
xfs_alloc_log_block(
	xfs_trans_t		*tp,	/* transaction pointer */
	xfs_buf_t		*bp,	/* buffer containing btree block */
	int			fields)	/* mask of fields: XFS_BB_... */
{
	int			first;	/* first byte offset logged */
	int			last;	/* last byte offset logged */
	static const short	offsets[] = {	/* table of offsets */
		offsetof(xfs_alloc_block_t, bb_magic),
		offsetof(xfs_alloc_block_t, bb_level),
		offsetof(xfs_alloc_block_t, bb_numrecs),
		offsetof(xfs_alloc_block_t, bb_leftsib),
		offsetof(xfs_alloc_block_t, bb_rightsib),
		sizeof(xfs_alloc_block_t)
	};

	xfs_btree_offsets(fields, offsets, XFS_BB_NUM_BITS, &first, &last);
	xfs_trans_log_buf(tp, bp, first, last);
}

/*
 * Log keys from a btree block (nonleaf).
 */
STATIC void
xfs_alloc_log_keys(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_buf_t		*bp,	/* buffer containing btree block */
	int			kfirst,	/* index of first key to log */
	int			klast)	/* index of last key to log */
{
	xfs_alloc_block_t	*block;	/* btree block to log from */
	int			first;	/* first byte offset logged */
	xfs_alloc_key_t		*kp;	/* key pointer in btree block */
	int			last;	/* last byte offset logged */

	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
	kp = XFS_ALLOC_KEY_ADDR(block, 1, cur);
	first = (int)((xfs_caddr_t)&kp[kfirst - 1] - (xfs_caddr_t)block);
	last = (int)(((xfs_caddr_t)&kp[klast] - 1) - (xfs_caddr_t)block);
	xfs_trans_log_buf(cur->bc_tp, bp, first, last);
}

/*
 * Log block pointer fields from a btree block (nonleaf).
 */
STATIC void
xfs_alloc_log_ptrs(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_buf_t		*bp,	/* buffer containing btree block */
	int			pfirst,	/* index of first pointer to log */
	int			plast)	/* index of last pointer to log */
{
	xfs_alloc_block_t	*block;	/* btree block to log from */
	int			first;	/* first byte offset logged */
	int			last;	/* last byte offset logged */
	xfs_alloc_ptr_t		*pp;	/* block-pointer pointer in btree blk */

	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
	pp = XFS_ALLOC_PTR_ADDR(block, 1, cur);
	first = (int)((xfs_caddr_t)&pp[pfirst - 1] - (xfs_caddr_t)block);
	last = (int)(((xfs_caddr_t)&pp[plast] - 1) - (xfs_caddr_t)block);
	xfs_trans_log_buf(cur->bc_tp, bp, first, last);
}

/*
 * Log records from a btree block (leaf).
 */
STATIC void
xfs_alloc_log_recs(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_buf_t		*bp,	/* buffer containing btree block */
	int			rfirst,	/* index of first record to log */
	int			rlast)	/* index of last record to log */
{
	xfs_alloc_block_t	*block;	/* btree block to log from */
	int			first;	/* first byte offset logged */
	int			last;	/* last byte offset logged */
	xfs_alloc_rec_t		*rp;	/* record pointer for btree block */


	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
	rp = XFS_ALLOC_REC_ADDR(block, 1, cur);
#ifdef DEBUG
	{
		xfs_agf_t	*agf;
		xfs_alloc_rec_t	*p;

		agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
		for (p = &rp[rfirst - 1]; p <= &rp[rlast - 1]; p++)
			ASSERT(be32_to_cpu(p->ar_startblock) +
			       be32_to_cpu(p->ar_blockcount) <=
			       be32_to_cpu(agf->agf_length));
	}
#endif
	first = (int)((xfs_caddr_t)&rp[rfirst - 1] - (xfs_caddr_t)block);
	last = (int)(((xfs_caddr_t)&rp[rlast] - 1) - (xfs_caddr_t)block);
	xfs_trans_log_buf(cur->bc_tp, bp, first, last);
}

/*
 * Allocate a new root block, fill it in.
 */
STATIC int				/* error */
xfs_alloc_newroot(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			*stat)	/* success/failure */
{
	int			error;	/* error return value */
	xfs_agblock_t		lbno;	/* left block number */
	xfs_buf_t		*lbp;	/* left btree buffer */
	xfs_alloc_block_t	*left;	/* left btree block */
	xfs_mount_t		*mp;	/* mount structure */
	xfs_agblock_t		nbno;	/* new block number */
	xfs_buf_t		*nbp;	/* new (root) buffer */
	xfs_alloc_block_t	*new;	/* new (root) btree block */
	int			nptr;	/* new value for key index, 1 or 2 */
	xfs_agblock_t		rbno;	/* right block number */
	xfs_buf_t		*rbp;	/* right btree buffer */
	xfs_alloc_block_t	*right;	/* right btree block */

	mp = cur->bc_mp;

	ASSERT(cur->bc_nlevels < XFS_AG_MAXLEVELS(mp));
	/*
	 * Get a buffer from the freelist blocks, for the new root.
	 */
	error = xfs_alloc_get_freelist(cur->bc_tp,
					cur->bc_private.a.agbp, &nbno, 1);
	if (error)
		return error;
	/*
	 * None available, we fail.
	 */
	if (nbno == NULLAGBLOCK) {
		*stat = 0;
		return 0;
	}
	xfs_trans_agbtree_delta(cur->bc_tp, 1);
	nbp = xfs_btree_get_bufs(mp, cur->bc_tp, cur->bc_private.a.agno, nbno,
		0);
	new = XFS_BUF_TO_ALLOC_BLOCK(nbp);
	/*
	 * Set the root data in the a.g. freespace structure.
	 */
	{
		xfs_agf_t	*agf;	/* a.g. freespace header */
		xfs_agnumber_t	seqno;

		agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
		agf->agf_roots[cur->bc_btnum] = cpu_to_be32(nbno);
		be32_add_cpu(&agf->agf_levels[cur->bc_btnum], 1);
		seqno = be32_to_cpu(agf->agf_seqno);
		mp->m_perag[seqno].pagf_levels[cur->bc_btnum]++;
		xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
			XFS_AGF_ROOTS | XFS_AGF_LEVELS);
	}
	/*
	 * At the previous root level there are now two blocks: the old
	 * root, and the new block generated when it was split.
	 * We don't know which one the cursor is pointing at, so we
	 * set up variables "left" and "right" for each case.
	 */
	lbp = cur->bc_bufs[cur->bc_nlevels - 1];
	left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, left, cur->bc_nlevels - 1, lbp)))
		return error;
#endif
	if (be32_to_cpu(left->bb_rightsib) != NULLAGBLOCK) {
		/*
		 * Our block is left, pick up the right block.
		 */
		lbno = XFS_DADDR_TO_AGBNO(mp, XFS_BUF_ADDR(lbp));
		rbno = be32_to_cpu(left->bb_rightsib);
		if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
				cur->bc_private.a.agno, rbno, 0, &rbp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
		if ((error = xfs_btree_check_sblock(cur, right,
				cur->bc_nlevels - 1, rbp)))
			return error;
		nptr = 1;
	} else {
		/*
		 * Our block is right, pick up the left block.
		 */
		rbp = lbp;
		right = left;
		rbno = XFS_DADDR_TO_AGBNO(mp, XFS_BUF_ADDR(rbp));
		lbno = be32_to_cpu(right->bb_leftsib);
		if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
				cur->bc_private.a.agno, lbno, 0, &lbp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
		if ((error = xfs_btree_check_sblock(cur, left,
				cur->bc_nlevels - 1, lbp)))
			return error;
		nptr = 2;
	}
	/*
	 * Fill in the new block's btree header and log it.
	 */
	new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
	new->bb_level = cpu_to_be16(cur->bc_nlevels);
	new->bb_numrecs = cpu_to_be16(2);
	new->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
	new->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
	xfs_alloc_log_block(cur->bc_tp, nbp, XFS_BB_ALL_BITS);
	ASSERT(lbno != NULLAGBLOCK && rbno != NULLAGBLOCK);
	/*
	 * Fill in the key data in the new root.
	 */
	{
		xfs_alloc_key_t		*kp;	/* btree key pointer */

		kp = XFS_ALLOC_KEY_ADDR(new, 1, cur);
		if (be16_to_cpu(left->bb_level) > 0) {
			kp[0] = *XFS_ALLOC_KEY_ADDR(left, 1, cur);
			kp[1] = *XFS_ALLOC_KEY_ADDR(right, 1, cur);
		} else {
			xfs_alloc_rec_t	*rp;	/* btree record pointer */

			rp = XFS_ALLOC_REC_ADDR(left, 1, cur);
			kp[0].ar_startblock = rp->ar_startblock;
			kp[0].ar_blockcount = rp->ar_blockcount;
			rp = XFS_ALLOC_REC_ADDR(right, 1, cur);
			kp[1].ar_startblock = rp->ar_startblock;
			kp[1].ar_blockcount = rp->ar_blockcount;
		}
	}
	xfs_alloc_log_keys(cur, nbp, 1, 2);
	/*
	 * Fill in the pointer data in the new root.
	 */
	{
		xfs_alloc_ptr_t		*pp;	/* btree address pointer */

		pp = XFS_ALLOC_PTR_ADDR(new, 1, cur);
		pp[0] = cpu_to_be32(lbno);
		pp[1] = cpu_to_be32(rbno);
	}
	xfs_alloc_log_ptrs(cur, nbp, 1, 2);
	/*
	 * Fix up the cursor.
	 */
	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
	cur->bc_ptrs[cur->bc_nlevels] = nptr;
	cur->bc_nlevels++;
	*stat = 1;
	return 0;
}

/*
 * Split cur/level block in half.
 * Return new block number and its first record (to be inserted into parent).
 */
STATIC int				/* error */
xfs_alloc_split(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level to split */
	xfs_agblock_t		*bnop,	/* output: block number allocated */
	xfs_alloc_key_t		*keyp,	/* output: first key of new block */
	xfs_btree_cur_t		**curp,	/* output: new cursor */
	int			*stat)	/* success/failure */
{
	int			error;	/* error return value */
	int			i;	/* loop index/record number */
	xfs_agblock_t		lbno;	/* left (current) block number */
	xfs_buf_t		*lbp;	/* buffer for left block */
	xfs_alloc_block_t	*left;	/* left (current) btree block */
	xfs_agblock_t		rbno;	/* right (new) block number */
	xfs_buf_t		*rbp;	/* buffer for right block */
	xfs_alloc_block_t	*right;	/* right (new) btree block */

	/*
	 * Allocate the new block from the freelist.
	 * If we can't do it, we're toast.  Give up.
	 */
	error = xfs_alloc_get_freelist(cur->bc_tp,
					 cur->bc_private.a.agbp, &rbno, 1);
	if (error)
		return error;
	if (rbno == NULLAGBLOCK) {
		*stat = 0;
		return 0;
	}
	xfs_trans_agbtree_delta(cur->bc_tp, 1);
	rbp = xfs_btree_get_bufs(cur->bc_mp, cur->bc_tp, cur->bc_private.a.agno,
		rbno, 0);
	/*
	 * Set up the new block as "right".
	 */
	right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
	/*
	 * "Left" is the current (according to the cursor) block.
	 */
	lbp = cur->bc_bufs[level];
	left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, left, level, lbp)))
		return error;
#endif
	/*
	 * Fill in the btree header for the new block.
	 */
	right->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
	right->bb_level = left->bb_level;
	right->bb_numrecs = cpu_to_be16(be16_to_cpu(left->bb_numrecs) / 2);
	/*
	 * Make sure that if there's an odd number of entries now, that
	 * each new block will have the same number of entries.
	 */
	if ((be16_to_cpu(left->bb_numrecs) & 1) &&
	    cur->bc_ptrs[level] <= be16_to_cpu(right->bb_numrecs) + 1)
		be16_add_cpu(&right->bb_numrecs, 1);
	i = be16_to_cpu(left->bb_numrecs) - be16_to_cpu(right->bb_numrecs) + 1;
	/*
	 * For non-leaf blocks, copy keys and addresses over to the new block.
	 */
	if (level > 0) {
		xfs_alloc_key_t	*lkp;	/* left btree key pointer */
		xfs_alloc_ptr_t	*lpp;	/* left btree address pointer */
		xfs_alloc_key_t	*rkp;	/* right btree key pointer */
		xfs_alloc_ptr_t	*rpp;	/* right btree address pointer */

		lkp = XFS_ALLOC_KEY_ADDR(left, i, cur);
		lpp = XFS_ALLOC_PTR_ADDR(left, i, cur);
		rkp = XFS_ALLOC_KEY_ADDR(right, 1, cur);
		rpp = XFS_ALLOC_PTR_ADDR(right, 1, cur);
#ifdef DEBUG
		for (i = 0; i < be16_to_cpu(right->bb_numrecs); i++) {
			if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(lpp[i]), level)))
				return error;
		}
#endif
		memcpy(rkp, lkp, be16_to_cpu(right->bb_numrecs) * sizeof(*rkp));
		memcpy(rpp, lpp, be16_to_cpu(right->bb_numrecs) * sizeof(*rpp));
		xfs_alloc_log_keys(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
		xfs_alloc_log_ptrs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
		*keyp = *rkp;
	}
	/*
	 * For leaf blocks, copy records over to the new block.
	 */
	else {
		xfs_alloc_rec_t	*lrp;	/* left btree record pointer */
		xfs_alloc_rec_t	*rrp;	/* right btree record pointer */

		lrp = XFS_ALLOC_REC_ADDR(left, i, cur);
		rrp = XFS_ALLOC_REC_ADDR(right, 1, cur);
		memcpy(rrp, lrp, be16_to_cpu(right->bb_numrecs) * sizeof(*rrp));
		xfs_alloc_log_recs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
		keyp->ar_startblock = rrp->ar_startblock;
		keyp->ar_blockcount = rrp->ar_blockcount;
	}
	/*
	 * Find the left block number by looking in the buffer.
	 * Adjust numrecs, sibling pointers.
	 */
	lbno = XFS_DADDR_TO_AGBNO(cur->bc_mp, XFS_BUF_ADDR(lbp));
	be16_add_cpu(&left->bb_numrecs, -(be16_to_cpu(right->bb_numrecs)));
	right->bb_rightsib = left->bb_rightsib;
	left->bb_rightsib = cpu_to_be32(rbno);
	right->bb_leftsib = cpu_to_be32(lbno);
	xfs_alloc_log_block(cur->bc_tp, rbp, XFS_BB_ALL_BITS);
	xfs_alloc_log_block(cur->bc_tp, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
	/*
	 * If there's a block to the new block's right, make that block
	 * point back to right instead of to left.
	 */
	if (be32_to_cpu(right->bb_rightsib) != NULLAGBLOCK) {
		xfs_alloc_block_t	*rrblock;	/* rr btree block */
		xfs_buf_t		*rrbp;		/* buffer for rrblock */

		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.a.agno, be32_to_cpu(right->bb_rightsib), 0,
				&rrbp, XFS_ALLOC_BTREE_REF)))
			return error;
		rrblock = XFS_BUF_TO_ALLOC_BLOCK(rrbp);
		if ((error = xfs_btree_check_sblock(cur, rrblock, level, rrbp)))
			return error;
		rrblock->bb_leftsib = cpu_to_be32(rbno);
		xfs_alloc_log_block(cur->bc_tp, rrbp, XFS_BB_LEFTSIB);
	}
	/*
	 * If the cursor is really in the right block, move it there.
	 * If it's just pointing past the last entry in left, then we'll
	 * insert there, so don't change anything in that case.
	 */
	if (cur->bc_ptrs[level] > be16_to_cpu(left->bb_numrecs) + 1) {
		xfs_btree_setbuf(cur, level, rbp);
		cur->bc_ptrs[level] -= be16_to_cpu(left->bb_numrecs);
	}
	/*
	 * If there are more levels, we'll need another cursor which refers to
	 * the right block, no matter where this cursor was.
	 */
	if (level + 1 < cur->bc_nlevels) {
		if ((error = xfs_btree_dup_cursor(cur, curp)))
			return error;
		(*curp)->bc_ptrs[level + 1]++;
	}
	*bnop = rbno;
	*stat = 1;
	return 0;
}

/*
 * Externally visible routines.
 */

/*
 * Delete the record pointed to by cur.
 * The cursor refers to the place where the record was (could be inserted)
 * when the operation returns.
 */
int					/* error */
xfs_alloc_delete(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		*stat)		/* success/failure */
{
	int		error;		/* error return value */
	int		i;		/* result code */
	int		level;		/* btree level */

	/*
	 * Go up the tree, starting at leaf level.
	 * If 2 is returned then a join was done; go to the next level.
	 * Otherwise we are done.
	 */
	for (level = 0, i = 2; i == 2; level++) {
		if ((error = xfs_alloc_delrec(cur, level, &i)))
			return error;
	}
	if (i == 0) {
		for (level = 1; level < cur->bc_nlevels; level++) {
			if (cur->bc_ptrs[level] == 0) {
				if ((error = xfs_btree_decrement(cur, level, &i)))
					return error;
				break;
			}
		}
	}
	*stat = i;
	return 0;
}

/*
 * Get the data from the pointed-to record.
 */
int					/* error */
xfs_alloc_get_rec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_agblock_t		*bno,	/* output: starting block of extent */
	xfs_extlen_t		*len,	/* output: length of extent */
	int			*stat)	/* output: success/failure */
{
	xfs_alloc_block_t	*block;	/* btree block */
#ifdef DEBUG
	int			error;	/* error return value */
#endif
	int			ptr;	/* record number */

	ptr = cur->bc_ptrs[0];
	block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[0]);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, 0, cur->bc_bufs[0])))
		return error;
#endif
	/*
	 * Off the right end or left end, return failure.
	 */
	if (ptr > be16_to_cpu(block->bb_numrecs) || ptr <= 0) {
		*stat = 0;
		return 0;
	}
	/*
	 * Point to the record and extract its data.
	 */
	{
		xfs_alloc_rec_t		*rec;	/* record data */

		rec = XFS_ALLOC_REC_ADDR(block, ptr, cur);
		*bno = be32_to_cpu(rec->ar_startblock);
		*len = be32_to_cpu(rec->ar_blockcount);
	}
	*stat = 1;
	return 0;
}

/*
 * Insert the current record at the point referenced by cur.
 * The cursor may be inconsistent on return if splits have been done.
 */
int					/* error */
xfs_alloc_insert(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		*stat)		/* success/failure */
{
	int		error;		/* error return value */
	int		i;		/* result value, 0 for failure */
	int		level;		/* current level number in btree */
	xfs_agblock_t	nbno;		/* new block number (split result) */
	xfs_btree_cur_t	*ncur;		/* new cursor (split result) */
	xfs_alloc_rec_t	nrec;		/* record being inserted this level */
	xfs_btree_cur_t	*pcur;		/* previous level's cursor */

	level = 0;
	nbno = NULLAGBLOCK;
	nrec.ar_startblock = cpu_to_be32(cur->bc_rec.a.ar_startblock);
	nrec.ar_blockcount = cpu_to_be32(cur->bc_rec.a.ar_blockcount);
	ncur = NULL;
	pcur = cur;
	/*
	 * Loop going up the tree, starting at the leaf level.
	 * Stop when we don't get a split block, that must mean that
	 * the insert is finished with this level.
	 */
	do {
		/*
		 * Insert nrec/nbno into this level of the tree.
		 * Note if we fail, nbno will be null.
		 */
		if ((error = xfs_alloc_insrec(pcur, level++, &nbno, &nrec, &ncur,
				&i))) {
			if (pcur != cur)
				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
			return error;
		}
		/*
		 * See if the cursor we just used is trash.
		 * Can't trash the caller's cursor, but otherwise we should
		 * if ncur is a new cursor or we're about to be done.
		 */
		if (pcur != cur && (ncur || nbno == NULLAGBLOCK)) {
			cur->bc_nlevels = pcur->bc_nlevels;
			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
		}
		/*
		 * If we got a new cursor, switch to it.
		 */
		if (ncur) {
			pcur = ncur;
			ncur = NULL;
		}
	} while (nbno != NULLAGBLOCK);
	*stat = i;
	return 0;
}

STATIC struct xfs_btree_cur *
xfs_allocbt_dup_cursor(
	struct xfs_btree_cur	*cur)
{
	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
			cur->bc_private.a.agbp, cur->bc_private.a.agno,
			cur->bc_btnum);
}

/*
 * Update the longest extent in the AGF
 */
STATIC void
xfs_allocbt_update_lastrec(
	struct xfs_btree_cur	*cur,
	struct xfs_btree_block	*block,
	union xfs_btree_rec	*rec,
	int			ptr,
	int			reason)
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
	__be32			len;

	ASSERT(cur->bc_btnum == XFS_BTNUM_CNT);

	switch (reason) {
	case LASTREC_UPDATE:
		/*
		 * If this is the last leaf block and it's the last record,
		 * then update the size of the longest extent in the AG.
		 */
		if (ptr != xfs_btree_get_numrecs(block))
			return;
		len = rec->alloc.ar_blockcount;
		break;
	default:
		ASSERT(0);
		return;
	}

	agf->agf_longest = len;
	cur->bc_mp->m_perag[seqno].pagf_longest = be32_to_cpu(len);
	xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp, XFS_AGF_LONGEST);
}

STATIC int
xfs_allocbt_get_maxrecs(
	struct xfs_btree_cur	*cur,
	int			level)
{
	return cur->bc_mp->m_alloc_mxr[level != 0];
}

STATIC void
xfs_allocbt_init_key_from_rec(
	union xfs_btree_key	*key,
	union xfs_btree_rec	*rec)
{
	ASSERT(rec->alloc.ar_startblock != 0);

	key->alloc.ar_startblock = rec->alloc.ar_startblock;
	key->alloc.ar_blockcount = rec->alloc.ar_blockcount;
}

STATIC void
xfs_allocbt_init_ptr_from_cur(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr)
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);

	ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
	ASSERT(agf->agf_roots[cur->bc_btnum] != 0);

	ptr->s = agf->agf_roots[cur->bc_btnum];
}

STATIC __int64_t
xfs_allocbt_key_diff(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*key)
{
	xfs_alloc_rec_incore_t	*rec = &cur->bc_rec.a;
	xfs_alloc_key_t		*kp = &key->alloc;
	__int64_t		diff;

	if (cur->bc_btnum == XFS_BTNUM_BNO) {
		return (__int64_t)be32_to_cpu(kp->ar_startblock) -
				rec->ar_startblock;
	}

	diff = (__int64_t)be32_to_cpu(kp->ar_blockcount) - rec->ar_blockcount;
	if (diff)
		return diff;

	return (__int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock;
}

#ifdef XFS_BTREE_TRACE
ktrace_t	*xfs_allocbt_trace_buf;

STATIC void
xfs_allocbt_trace_enter(
	struct xfs_btree_cur	*cur,
	const char		*func,
	char			*s,
	int			type,
	int			line,
	__psunsigned_t		a0,
	__psunsigned_t		a1,
	__psunsigned_t		a2,
	__psunsigned_t		a3,
	__psunsigned_t		a4,
	__psunsigned_t		a5,
	__psunsigned_t		a6,
	__psunsigned_t		a7,
	__psunsigned_t		a8,
	__psunsigned_t		a9,
	__psunsigned_t		a10)
{
	ktrace_enter(xfs_allocbt_trace_buf, (void *)(__psint_t)type,
		(void *)func, (void *)s, NULL, (void *)cur,
		(void *)a0, (void *)a1, (void *)a2, (void *)a3,
		(void *)a4, (void *)a5, (void *)a6, (void *)a7,
		(void *)a8, (void *)a9, (void *)a10);
}

STATIC void
xfs_allocbt_trace_cursor(
	struct xfs_btree_cur	*cur,
	__uint32_t		*s0,
	__uint64_t		*l0,
	__uint64_t		*l1)
{
	*s0 = cur->bc_private.a.agno;
	*l0 = cur->bc_rec.a.ar_startblock;
	*l1 = cur->bc_rec.a.ar_blockcount;
}

STATIC void
xfs_allocbt_trace_key(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*key,
	__uint64_t		*l0,
	__uint64_t		*l1)
{
	*l0 = be32_to_cpu(key->alloc.ar_startblock);
	*l1 = be32_to_cpu(key->alloc.ar_blockcount);
}

STATIC void
xfs_allocbt_trace_record(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*rec,
	__uint64_t		*l0,
	__uint64_t		*l1,
	__uint64_t		*l2)
{
	*l0 = be32_to_cpu(rec->alloc.ar_startblock);
	*l1 = be32_to_cpu(rec->alloc.ar_blockcount);
	*l2 = 0;
}
#endif /* XFS_BTREE_TRACE */

static const struct xfs_btree_ops xfs_allocbt_ops = {
	.rec_len		= sizeof(xfs_alloc_rec_t),
	.key_len		= sizeof(xfs_alloc_key_t),

	.dup_cursor		= xfs_allocbt_dup_cursor,
	.update_lastrec		= xfs_allocbt_update_lastrec,
	.get_maxrecs		= xfs_allocbt_get_maxrecs,
	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
	.key_diff		= xfs_allocbt_key_diff,

#ifdef XFS_BTREE_TRACE
	.trace_enter		= xfs_allocbt_trace_enter,
	.trace_cursor		= xfs_allocbt_trace_cursor,
	.trace_key		= xfs_allocbt_trace_key,
	.trace_record		= xfs_allocbt_trace_record,
#endif
};

/*
 * Allocate a new allocation btree cursor.
 */
struct xfs_btree_cur *			/* new alloc btree cursor */
xfs_allocbt_init_cursor(
	struct xfs_mount	*mp,		/* file system mount point */
	struct xfs_trans	*tp,		/* transaction pointer */
	struct xfs_buf		*agbp,		/* buffer for agf structure */
	xfs_agnumber_t		agno,		/* allocation group number */
	xfs_btnum_t		btnum)		/* btree identifier */
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
	struct xfs_btree_cur	*cur;

	ASSERT(btnum == XFS_BTNUM_BNO || btnum == XFS_BTNUM_CNT);

	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);

	cur->bc_tp = tp;
	cur->bc_mp = mp;
	cur->bc_nlevels = be32_to_cpu(agf->agf_levels[btnum]);
	cur->bc_btnum = btnum;
	cur->bc_blocklog = mp->m_sb.sb_blocklog;

	cur->bc_ops = &xfs_allocbt_ops;
	if (btnum == XFS_BTNUM_CNT)
		cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;

	cur->bc_private.a.agbp = agbp;
	cur->bc_private.a.agno = agno;

	return cur;
}