summaryrefslogtreecommitdiff
path: root/fs/xfs/libxfs/xfs_inode_fork.c
blob: d3d1477bfb9e4af8aa96a8614f4e6dc4f5d5a503 (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
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
/*
 * Copyright (c) 2000-2006 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 <linux/log2.h>

#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_attr_sf.h"
#include "xfs_da_format.h"

kmem_zone_t *xfs_ifork_zone;

STATIC int xfs_iformat_local(xfs_inode_t *, xfs_dinode_t *, int, int);
STATIC int xfs_iformat_extents(xfs_inode_t *, xfs_dinode_t *, int);
STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);

#ifdef DEBUG
/*
 * Make sure that the extents in the given memory buffer
 * are valid.
 */
void
xfs_validate_extents(
	xfs_ifork_t		*ifp,
	int			nrecs,
	xfs_exntfmt_t		fmt)
{
	xfs_bmbt_irec_t		irec;
	xfs_bmbt_rec_host_t	rec;
	int			i;

	for (i = 0; i < nrecs; i++) {
		xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
		rec.l0 = get_unaligned(&ep->l0);
		rec.l1 = get_unaligned(&ep->l1);
		xfs_bmbt_get_all(&rec, &irec);
		if (fmt == XFS_EXTFMT_NOSTATE)
			ASSERT(irec.br_state == XFS_EXT_NORM);
	}
}
#else /* DEBUG */
#define xfs_validate_extents(ifp, nrecs, fmt)
#endif /* DEBUG */


/*
 * Move inode type and inode format specific information from the
 * on-disk inode to the in-core inode.  For fifos, devs, and sockets
 * this means set if_rdev to the proper value.  For files, directories,
 * and symlinks this means to bring in the in-line data or extent
 * pointers.  For a file in B-tree format, only the root is immediately
 * brought in-core.  The rest will be in-lined in if_extents when it
 * is first referenced (see xfs_iread_extents()).
 */
int
xfs_iformat_fork(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip)
{
	xfs_attr_shortform_t	*atp;
	int			size;
	int			error = 0;
	xfs_fsize_t             di_size;

	if (unlikely(be32_to_cpu(dip->di_nextents) +
		     be16_to_cpu(dip->di_anextents) >
		     be64_to_cpu(dip->di_nblocks))) {
		xfs_warn(ip->i_mount,
			"corrupt dinode %Lu, extent total = %d, nblocks = %Lu.",
			(unsigned long long)ip->i_ino,
			(int)(be32_to_cpu(dip->di_nextents) +
			      be16_to_cpu(dip->di_anextents)),
			(unsigned long long)
				be64_to_cpu(dip->di_nblocks));
		XFS_CORRUPTION_ERROR("xfs_iformat(1)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return -EFSCORRUPTED;
	}

	if (unlikely(dip->di_forkoff > ip->i_mount->m_sb.sb_inodesize)) {
		xfs_warn(ip->i_mount, "corrupt dinode %Lu, forkoff = 0x%x.",
			(unsigned long long)ip->i_ino,
			dip->di_forkoff);
		XFS_CORRUPTION_ERROR("xfs_iformat(2)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return -EFSCORRUPTED;
	}

	if (unlikely((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) &&
		     !ip->i_mount->m_rtdev_targp)) {
		xfs_warn(ip->i_mount,
			"corrupt dinode %Lu, has realtime flag set.",
			ip->i_ino);
		XFS_CORRUPTION_ERROR("xfs_iformat(realtime)",
				     XFS_ERRLEVEL_LOW, ip->i_mount, dip);
		return -EFSCORRUPTED;
	}

	switch (VFS_I(ip)->i_mode & S_IFMT) {
	case S_IFIFO:
	case S_IFCHR:
	case S_IFBLK:
	case S_IFSOCK:
		if (unlikely(dip->di_format != XFS_DINODE_FMT_DEV)) {
			XFS_CORRUPTION_ERROR("xfs_iformat(3)", XFS_ERRLEVEL_LOW,
					      ip->i_mount, dip);
			return -EFSCORRUPTED;
		}
		ip->i_d.di_size = 0;
		ip->i_df.if_u2.if_rdev = xfs_dinode_get_rdev(dip);
		break;

	case S_IFREG:
	case S_IFLNK:
	case S_IFDIR:
		switch (dip->di_format) {
		case XFS_DINODE_FMT_LOCAL:
			/*
			 * no local regular files yet
			 */
			if (unlikely(S_ISREG(be16_to_cpu(dip->di_mode)))) {
				xfs_warn(ip->i_mount,
			"corrupt inode %Lu (local format for regular file).",
					(unsigned long long) ip->i_ino);
				XFS_CORRUPTION_ERROR("xfs_iformat(4)",
						     XFS_ERRLEVEL_LOW,
						     ip->i_mount, dip);
				return -EFSCORRUPTED;
			}

			di_size = be64_to_cpu(dip->di_size);
			if (unlikely(di_size < 0 ||
				     di_size > XFS_DFORK_DSIZE(dip, ip->i_mount))) {
				xfs_warn(ip->i_mount,
			"corrupt inode %Lu (bad size %Ld for local inode).",
					(unsigned long long) ip->i_ino,
					(long long) di_size);
				XFS_CORRUPTION_ERROR("xfs_iformat(5)",
						     XFS_ERRLEVEL_LOW,
						     ip->i_mount, dip);
				return -EFSCORRUPTED;
			}

			size = (int)di_size;
			error = xfs_iformat_local(ip, dip, XFS_DATA_FORK, size);
			break;
		case XFS_DINODE_FMT_EXTENTS:
			error = xfs_iformat_extents(ip, dip, XFS_DATA_FORK);
			break;
		case XFS_DINODE_FMT_BTREE:
			error = xfs_iformat_btree(ip, dip, XFS_DATA_FORK);
			break;
		default:
			XFS_ERROR_REPORT("xfs_iformat(6)", XFS_ERRLEVEL_LOW,
					 ip->i_mount);
			return -EFSCORRUPTED;
		}
		break;

	default:
		XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount);
		return -EFSCORRUPTED;
	}
	if (error) {
		return error;
	}
	if (!XFS_DFORK_Q(dip))
		return 0;

	ASSERT(ip->i_afp == NULL);
	ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP | KM_NOFS);

	switch (dip->di_aformat) {
	case XFS_DINODE_FMT_LOCAL:
		atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
		size = be16_to_cpu(atp->hdr.totsize);

		if (unlikely(size < sizeof(struct xfs_attr_sf_hdr))) {
			xfs_warn(ip->i_mount,
				"corrupt inode %Lu (bad attr fork size %Ld).",
				(unsigned long long) ip->i_ino,
				(long long) size);
			XFS_CORRUPTION_ERROR("xfs_iformat(8)",
					     XFS_ERRLEVEL_LOW,
					     ip->i_mount, dip);
			return -EFSCORRUPTED;
		}

		error = xfs_iformat_local(ip, dip, XFS_ATTR_FORK, size);
		break;
	case XFS_DINODE_FMT_EXTENTS:
		error = xfs_iformat_extents(ip, dip, XFS_ATTR_FORK);
		break;
	case XFS_DINODE_FMT_BTREE:
		error = xfs_iformat_btree(ip, dip, XFS_ATTR_FORK);
		break;
	default:
		error = -EFSCORRUPTED;
		break;
	}
	if (error) {
		kmem_zone_free(xfs_ifork_zone, ip->i_afp);
		ip->i_afp = NULL;
		xfs_idestroy_fork(ip, XFS_DATA_FORK);
	}
	return error;
}

void
xfs_init_local_fork(
	struct xfs_inode	*ip,
	int			whichfork,
	const void		*data,
	int			size)
{
	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
	int			mem_size = size, real_size = 0;
	bool			zero_terminate;

	/*
	 * If we are using the local fork to store a symlink body we need to
	 * zero-terminate it so that we can pass it back to the VFS directly.
	 * Overallocate the in-memory fork by one for that and add a zero
	 * to terminate it below.
	 */
	zero_terminate = S_ISLNK(VFS_I(ip)->i_mode);
	if (zero_terminate)
		mem_size++;

	if (size == 0)
		ifp->if_u1.if_data = NULL;
	else if (mem_size <= sizeof(ifp->if_u2.if_inline_data))
		ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
	else {
		real_size = roundup(mem_size, 4);
		ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS);
	}

	if (size) {
		memcpy(ifp->if_u1.if_data, data, size);
		if (zero_terminate)
			ifp->if_u1.if_data[size] = '\0';
	}

	ifp->if_bytes = size;
	ifp->if_real_bytes = real_size;
	ifp->if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
	ifp->if_flags |= XFS_IFINLINE;
}

/*
 * The file is in-lined in the on-disk inode.
 * If it fits into if_inline_data, then copy
 * it there, otherwise allocate a buffer for it
 * and copy the data there.  Either way, set
 * if_data to point at the data.
 * If we allocate a buffer for the data, make
 * sure that its size is a multiple of 4 and
 * record the real size in i_real_bytes.
 */
STATIC int
xfs_iformat_local(
	xfs_inode_t	*ip,
	xfs_dinode_t	*dip,
	int		whichfork,
	int		size)
{

	/*
	 * If the size is unreasonable, then something
	 * is wrong and we just bail out rather than crash in
	 * kmem_alloc() or memcpy() below.
	 */
	if (unlikely(size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
		xfs_warn(ip->i_mount,
	"corrupt inode %Lu (bad size %d for local fork, size = %d).",
			(unsigned long long) ip->i_ino, size,
			XFS_DFORK_SIZE(dip, ip->i_mount, whichfork));
		XFS_CORRUPTION_ERROR("xfs_iformat_local", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return -EFSCORRUPTED;
	}

	xfs_init_local_fork(ip, whichfork, XFS_DFORK_PTR(dip, whichfork), size);
	return 0;
}

/*
 * The file consists of a set of extents all
 * of which fit into the on-disk inode.
 * If there are few enough extents to fit into
 * the if_inline_ext, then copy them there.
 * Otherwise allocate a buffer for them and copy
 * them into it.  Either way, set if_extents
 * to point at the extents.
 */
STATIC int
xfs_iformat_extents(
	xfs_inode_t	*ip,
	xfs_dinode_t	*dip,
	int		whichfork)
{
	xfs_bmbt_rec_t	*dp;
	xfs_ifork_t	*ifp;
	int		nex;
	int		size;
	int		i;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	nex = XFS_DFORK_NEXTENTS(dip, whichfork);
	size = nex * (uint)sizeof(xfs_bmbt_rec_t);

	/*
	 * If the number of extents is unreasonable, then something
	 * is wrong and we just bail out rather than crash in
	 * kmem_alloc() or memcpy() below.
	 */
	if (unlikely(size < 0 || size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
		xfs_warn(ip->i_mount, "corrupt inode %Lu ((a)extents = %d).",
			(unsigned long long) ip->i_ino, nex);
		XFS_CORRUPTION_ERROR("xfs_iformat_extents(1)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return -EFSCORRUPTED;
	}

	ifp->if_real_bytes = 0;
	if (nex == 0)
		ifp->if_u1.if_extents = NULL;
	else if (nex <= XFS_INLINE_EXTS)
		ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
	else
		xfs_iext_add(ifp, 0, nex);

	ifp->if_bytes = size;
	if (size) {
		dp = (xfs_bmbt_rec_t *) XFS_DFORK_PTR(dip, whichfork);
		xfs_validate_extents(ifp, nex, XFS_EXTFMT_INODE(ip));
		for (i = 0; i < nex; i++, dp++) {
			xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
			ep->l0 = get_unaligned_be64(&dp->l0);
			ep->l1 = get_unaligned_be64(&dp->l1);
		}
		XFS_BMAP_TRACE_EXLIST(ip, nex, whichfork);
		if (whichfork != XFS_DATA_FORK ||
			XFS_EXTFMT_INODE(ip) == XFS_EXTFMT_NOSTATE)
				if (unlikely(xfs_check_nostate_extents(
				    ifp, 0, nex))) {
					XFS_ERROR_REPORT("xfs_iformat_extents(2)",
							 XFS_ERRLEVEL_LOW,
							 ip->i_mount);
					return -EFSCORRUPTED;
				}
	}
	ifp->if_flags |= XFS_IFEXTENTS;
	return 0;
}

/*
 * The file has too many extents to fit into
 * the inode, so they are in B-tree format.
 * Allocate a buffer for the root of the B-tree
 * and copy the root into it.  The i_extents
 * field will remain NULL until all of the
 * extents are read in (when they are needed).
 */
STATIC int
xfs_iformat_btree(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip,
	int			whichfork)
{
	struct xfs_mount	*mp = ip->i_mount;
	xfs_bmdr_block_t	*dfp;
	xfs_ifork_t		*ifp;
	/* REFERENCED */
	int			nrecs;
	int			size;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	dfp = (xfs_bmdr_block_t *)XFS_DFORK_PTR(dip, whichfork);
	size = XFS_BMAP_BROOT_SPACE(mp, dfp);
	nrecs = be16_to_cpu(dfp->bb_numrecs);

	/*
	 * blow out if -- fork has less extents than can fit in
	 * fork (fork shouldn't be a btree format), root btree
	 * block has more records than can fit into the fork,
	 * or the number of extents is greater than the number of
	 * blocks.
	 */
	if (unlikely(XFS_IFORK_NEXTENTS(ip, whichfork) <=
					XFS_IFORK_MAXEXT(ip, whichfork) ||
		     XFS_BMDR_SPACE_CALC(nrecs) >
					XFS_DFORK_SIZE(dip, mp, whichfork) ||
		     XFS_IFORK_NEXTENTS(ip, whichfork) > ip->i_d.di_nblocks)) {
		xfs_warn(mp, "corrupt inode %Lu (btree).",
					(unsigned long long) ip->i_ino);
		XFS_CORRUPTION_ERROR("xfs_iformat_btree", XFS_ERRLEVEL_LOW,
					 mp, dip);
		return -EFSCORRUPTED;
	}

	ifp->if_broot_bytes = size;
	ifp->if_broot = kmem_alloc(size, KM_SLEEP | KM_NOFS);
	ASSERT(ifp->if_broot != NULL);
	/*
	 * Copy and convert from the on-disk structure
	 * to the in-memory structure.
	 */
	xfs_bmdr_to_bmbt(ip, dfp, XFS_DFORK_SIZE(dip, ip->i_mount, whichfork),
			 ifp->if_broot, size);
	ifp->if_flags &= ~XFS_IFEXTENTS;
	ifp->if_flags |= XFS_IFBROOT;

	return 0;
}

/*
 * Read in extents from a btree-format inode.
 * Allocate and fill in if_extents.  Real work is done in xfs_bmap.c.
 */
int
xfs_iread_extents(
	xfs_trans_t	*tp,
	xfs_inode_t	*ip,
	int		whichfork)
{
	int		error;
	xfs_ifork_t	*ifp;
	xfs_extnum_t	nextents;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

	if (unlikely(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
		XFS_ERROR_REPORT("xfs_iread_extents", XFS_ERRLEVEL_LOW,
				 ip->i_mount);
		return -EFSCORRUPTED;
	}
	nextents = XFS_IFORK_NEXTENTS(ip, whichfork);
	ifp = XFS_IFORK_PTR(ip, whichfork);

	/*
	 * We know that the size is valid (it's checked in iformat_btree)
	 */
	ifp->if_bytes = ifp->if_real_bytes = 0;
	ifp->if_flags |= XFS_IFEXTENTS;
	xfs_iext_add(ifp, 0, nextents);
	error = xfs_bmap_read_extents(tp, ip, whichfork);
	if (error) {
		xfs_iext_destroy(ifp);
		ifp->if_flags &= ~XFS_IFEXTENTS;
		return error;
	}
	xfs_validate_extents(ifp, nextents, XFS_EXTFMT_INODE(ip));
	return 0;
}
/*
 * Reallocate the space for if_broot based on the number of records
 * being added or deleted as indicated in rec_diff.  Move the records
 * and pointers in if_broot to fit the new size.  When shrinking this
 * will eliminate holes between the records and pointers created by
 * the caller.  When growing this will create holes to be filled in
 * by the caller.
 *
 * The caller must not request to add more records than would fit in
 * the on-disk inode root.  If the if_broot is currently NULL, then
 * if we are adding records, one will be allocated.  The caller must also
 * not request that the number of records go below zero, although
 * it can go to zero.
 *
 * ip -- the inode whose if_broot area is changing
 * ext_diff -- the change in the number of records, positive or negative,
 *	 requested for the if_broot array.
 */
void
xfs_iroot_realloc(
	xfs_inode_t		*ip,
	int			rec_diff,
	int			whichfork)
{
	struct xfs_mount	*mp = ip->i_mount;
	int			cur_max;
	xfs_ifork_t		*ifp;
	struct xfs_btree_block	*new_broot;
	int			new_max;
	size_t			new_size;
	char			*np;
	char			*op;

	/*
	 * Handle the degenerate case quietly.
	 */
	if (rec_diff == 0) {
		return;
	}

	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (rec_diff > 0) {
		/*
		 * If there wasn't any memory allocated before, just
		 * allocate it now and get out.
		 */
		if (ifp->if_broot_bytes == 0) {
			new_size = XFS_BMAP_BROOT_SPACE_CALC(mp, rec_diff);
			ifp->if_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
			ifp->if_broot_bytes = (int)new_size;
			return;
		}

		/*
		 * If there is already an existing if_broot, then we need
		 * to realloc() it and shift the pointers to their new
		 * location.  The records don't change location because
		 * they are kept butted up against the btree block header.
		 */
		cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
		new_max = cur_max + rec_diff;
		new_size = XFS_BMAP_BROOT_SPACE_CALC(mp, new_max);
		ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
				KM_SLEEP | KM_NOFS);
		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     ifp->if_broot_bytes);
		np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     (int)new_size);
		ifp->if_broot_bytes = (int)new_size;
		ASSERT(XFS_BMAP_BMDR_SPACE(ifp->if_broot) <=
			XFS_IFORK_SIZE(ip, whichfork));
		memmove(np, op, cur_max * (uint)sizeof(xfs_fsblock_t));
		return;
	}

	/*
	 * rec_diff is less than 0.  In this case, we are shrinking the
	 * if_broot buffer.  It must already exist.  If we go to zero
	 * records, just get rid of the root and clear the status bit.
	 */
	ASSERT((ifp->if_broot != NULL) && (ifp->if_broot_bytes > 0));
	cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
	new_max = cur_max + rec_diff;
	ASSERT(new_max >= 0);
	if (new_max > 0)
		new_size = XFS_BMAP_BROOT_SPACE_CALC(mp, new_max);
	else
		new_size = 0;
	if (new_size > 0) {
		new_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
		/*
		 * First copy over the btree block header.
		 */
		memcpy(new_broot, ifp->if_broot,
			XFS_BMBT_BLOCK_LEN(ip->i_mount));
	} else {
		new_broot = NULL;
		ifp->if_flags &= ~XFS_IFBROOT;
	}

	/*
	 * Only copy the records and pointers if there are any.
	 */
	if (new_max > 0) {
		/*
		 * First copy the records.
		 */
		op = (char *)XFS_BMBT_REC_ADDR(mp, ifp->if_broot, 1);
		np = (char *)XFS_BMBT_REC_ADDR(mp, new_broot, 1);
		memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_rec_t));

		/*
		 * Then copy the pointers.
		 */
		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     ifp->if_broot_bytes);
		np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, new_broot, 1,
						     (int)new_size);
		memcpy(np, op, new_max * (uint)sizeof(xfs_fsblock_t));
	}
	kmem_free(ifp->if_broot);
	ifp->if_broot = new_broot;
	ifp->if_broot_bytes = (int)new_size;
	if (ifp->if_broot)
		ASSERT(XFS_BMAP_BMDR_SPACE(ifp->if_broot) <=
			XFS_IFORK_SIZE(ip, whichfork));
	return;
}


/*
 * This is called when the amount of space needed for if_data
 * is increased or decreased.  The change in size is indicated by
 * the number of bytes that need to be added or deleted in the
 * byte_diff parameter.
 *
 * If the amount of space needed has decreased below the size of the
 * inline buffer, then switch to using the inline buffer.  Otherwise,
 * use kmem_realloc() or kmem_alloc() to adjust the size of the buffer
 * to what is needed.
 *
 * ip -- the inode whose if_data area is changing
 * byte_diff -- the change in the number of bytes, positive or negative,
 *	 requested for the if_data array.
 */
void
xfs_idata_realloc(
	xfs_inode_t	*ip,
	int		byte_diff,
	int		whichfork)
{
	xfs_ifork_t	*ifp;
	int		new_size;
	int		real_size;

	if (byte_diff == 0) {
		return;
	}

	ifp = XFS_IFORK_PTR(ip, whichfork);
	new_size = (int)ifp->if_bytes + byte_diff;
	ASSERT(new_size >= 0);

	if (new_size == 0) {
		if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			kmem_free(ifp->if_u1.if_data);
		}
		ifp->if_u1.if_data = NULL;
		real_size = 0;
	} else if (new_size <= sizeof(ifp->if_u2.if_inline_data)) {
		/*
		 * If the valid extents/data can fit in if_inline_ext/data,
		 * copy them from the malloc'd vector and free it.
		 */
		if (ifp->if_u1.if_data == NULL) {
			ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
		} else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			ASSERT(ifp->if_real_bytes != 0);
			memcpy(ifp->if_u2.if_inline_data, ifp->if_u1.if_data,
			      new_size);
			kmem_free(ifp->if_u1.if_data);
			ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
		}
		real_size = 0;
	} else {
		/*
		 * Stuck with malloc/realloc.
		 * For inline data, the underlying buffer must be
		 * a multiple of 4 bytes in size so that it can be
		 * logged and stay on word boundaries.  We enforce
		 * that here.
		 */
		real_size = roundup(new_size, 4);
		if (ifp->if_u1.if_data == NULL) {
			ASSERT(ifp->if_real_bytes == 0);
			ifp->if_u1.if_data = kmem_alloc(real_size,
							KM_SLEEP | KM_NOFS);
		} else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			/*
			 * Only do the realloc if the underlying size
			 * is really changing.
			 */
			if (ifp->if_real_bytes != real_size) {
				ifp->if_u1.if_data =
					kmem_realloc(ifp->if_u1.if_data,
							real_size,
							KM_SLEEP | KM_NOFS);
			}
		} else {
			ASSERT(ifp->if_real_bytes == 0);
			ifp->if_u1.if_data = kmem_alloc(real_size,
							KM_SLEEP | KM_NOFS);
			memcpy(ifp->if_u1.if_data, ifp->if_u2.if_inline_data,
				ifp->if_bytes);
		}
	}
	ifp->if_real_bytes = real_size;
	ifp->if_bytes = new_size;
	ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
}

void
xfs_idestroy_fork(
	xfs_inode_t	*ip,
	int		whichfork)
{
	xfs_ifork_t	*ifp;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (ifp->if_broot != NULL) {
		kmem_free(ifp->if_broot);
		ifp->if_broot = NULL;
	}

	/*
	 * If the format is local, then we can't have an extents
	 * array so just look for an inline data array.  If we're
	 * not local then we may or may not have an extents list,
	 * so check and free it up if we do.
	 */
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		if ((ifp->if_u1.if_data != ifp->if_u2.if_inline_data) &&
		    (ifp->if_u1.if_data != NULL)) {
			ASSERT(ifp->if_real_bytes != 0);
			kmem_free(ifp->if_u1.if_data);
			ifp->if_u1.if_data = NULL;
			ifp->if_real_bytes = 0;
		}
	} else if ((ifp->if_flags & XFS_IFEXTENTS) &&
		   ((ifp->if_flags & XFS_IFEXTIREC) ||
		    ((ifp->if_u1.if_extents != NULL) &&
		     (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)))) {
		ASSERT(ifp->if_real_bytes != 0);
		xfs_iext_destroy(ifp);
	}
	ASSERT(ifp->if_u1.if_extents == NULL ||
	       ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext);
	ASSERT(ifp->if_real_bytes == 0);
	if (whichfork == XFS_ATTR_FORK) {
		kmem_zone_free(xfs_ifork_zone, ip->i_afp);
		ip->i_afp = NULL;
	}
}

/*
 * Convert in-core extents to on-disk form
 *
 * For either the data or attr fork in extent format, we need to endian convert
 * the in-core extent as we place them into the on-disk inode.
 *
 * In the case of the data fork, the in-core and on-disk fork sizes can be
 * different due to delayed allocation extents. We only copy on-disk extents
 * here, so callers must always use the physical fork size to determine the
 * size of the buffer passed to this routine.  We will return the size actually
 * used.
 */
int
xfs_iextents_copy(
	xfs_inode_t		*ip,
	xfs_bmbt_rec_t		*dp,
	int			whichfork)
{
	int			copied;
	int			i;
	xfs_ifork_t		*ifp;
	int			nrecs;
	xfs_fsblock_t		start_block;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
	ASSERT(ifp->if_bytes > 0);

	nrecs = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	XFS_BMAP_TRACE_EXLIST(ip, nrecs, whichfork);
	ASSERT(nrecs > 0);

	/*
	 * There are some delayed allocation extents in the
	 * inode, so copy the extents one at a time and skip
	 * the delayed ones.  There must be at least one
	 * non-delayed extent.
	 */
	copied = 0;
	for (i = 0; i < nrecs; i++) {
		xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
		start_block = xfs_bmbt_get_startblock(ep);
		if (isnullstartblock(start_block)) {
			/*
			 * It's a delayed allocation extent, so skip it.
			 */
			continue;
		}

		/* Translate to on disk format */
		put_unaligned_be64(ep->l0, &dp->l0);
		put_unaligned_be64(ep->l1, &dp->l1);
		dp++;
		copied++;
	}
	ASSERT(copied != 0);
	xfs_validate_extents(ifp, copied, XFS_EXTFMT_INODE(ip));

	return (copied * (uint)sizeof(xfs_bmbt_rec_t));
}

/*
 * Each of the following cases stores data into the same region
 * of the on-disk inode, so only one of them can be valid at
 * any given time. While it is possible to have conflicting formats
 * and log flags, e.g. having XFS_ILOG_?DATA set when the fork is
 * in EXTENTS format, this can only happen when the fork has
 * changed formats after being modified but before being flushed.
 * In these cases, the format always takes precedence, because the
 * format indicates the current state of the fork.
 */
void
xfs_iflush_fork(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip,
	xfs_inode_log_item_t	*iip,
	int			whichfork)
{
	char			*cp;
	xfs_ifork_t		*ifp;
	xfs_mount_t		*mp;
	static const short	brootflag[2] =
		{ XFS_ILOG_DBROOT, XFS_ILOG_ABROOT };
	static const short	dataflag[2] =
		{ XFS_ILOG_DDATA, XFS_ILOG_ADATA };
	static const short	extflag[2] =
		{ XFS_ILOG_DEXT, XFS_ILOG_AEXT };

	if (!iip)
		return;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	/*
	 * This can happen if we gave up in iformat in an error path,
	 * for the attribute fork.
	 */
	if (!ifp) {
		ASSERT(whichfork == XFS_ATTR_FORK);
		return;
	}
	cp = XFS_DFORK_PTR(dip, whichfork);
	mp = ip->i_mount;
	switch (XFS_IFORK_FORMAT(ip, whichfork)) {
	case XFS_DINODE_FMT_LOCAL:
		if ((iip->ili_fields & dataflag[whichfork]) &&
		    (ifp->if_bytes > 0)) {
			ASSERT(ifp->if_u1.if_data != NULL);
			ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
			memcpy(cp, ifp->if_u1.if_data, ifp->if_bytes);
		}
		break;

	case XFS_DINODE_FMT_EXTENTS:
		ASSERT((ifp->if_flags & XFS_IFEXTENTS) ||
		       !(iip->ili_fields & extflag[whichfork]));
		if ((iip->ili_fields & extflag[whichfork]) &&
		    (ifp->if_bytes > 0)) {
			ASSERT(xfs_iext_get_ext(ifp, 0));
			ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) > 0);
			(void)xfs_iextents_copy(ip, (xfs_bmbt_rec_t *)cp,
				whichfork);
		}
		break;

	case XFS_DINODE_FMT_BTREE:
		if ((iip->ili_fields & brootflag[whichfork]) &&
		    (ifp->if_broot_bytes > 0)) {
			ASSERT(ifp->if_broot != NULL);
			ASSERT(XFS_BMAP_BMDR_SPACE(ifp->if_broot) <=
			        XFS_IFORK_SIZE(ip, whichfork));
			xfs_bmbt_to_bmdr(mp, ifp->if_broot, ifp->if_broot_bytes,
				(xfs_bmdr_block_t *)cp,
				XFS_DFORK_SIZE(dip, mp, whichfork));
		}
		break;

	case XFS_DINODE_FMT_DEV:
		if (iip->ili_fields & XFS_ILOG_DEV) {
			ASSERT(whichfork == XFS_DATA_FORK);
			xfs_dinode_put_rdev(dip, ip->i_df.if_u2.if_rdev);
		}
		break;

	case XFS_DINODE_FMT_UUID:
		if (iip->ili_fields & XFS_ILOG_UUID) {
			ASSERT(whichfork == XFS_DATA_FORK);
			memcpy(XFS_DFORK_DPTR(dip),
			       &ip->i_df.if_u2.if_uuid,
			       sizeof(uuid_t));
		}
		break;

	default:
		ASSERT(0);
		break;
	}
}

/*
 * Return a pointer to the extent record at file index idx.
 */
xfs_bmbt_rec_host_t *
xfs_iext_get_ext(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx)		/* index of target extent */
{
	ASSERT(idx >= 0);
	ASSERT(idx < ifp->if_bytes / sizeof(xfs_bmbt_rec_t));

	if ((ifp->if_flags & XFS_IFEXTIREC) && (idx == 0)) {
		return ifp->if_u1.if_ext_irec->er_extbuf;
	} else if (ifp->if_flags & XFS_IFEXTIREC) {
		xfs_ext_irec_t	*erp;		/* irec pointer */
		int		erp_idx = 0;	/* irec index */
		xfs_extnum_t	page_idx = idx;	/* ext index in target list */

		erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 0);
		return &erp->er_extbuf[page_idx];
	} else if (ifp->if_bytes) {
		return &ifp->if_u1.if_extents[idx];
	} else {
		return NULL;
	}
}

/*
 * Insert new item(s) into the extent records for incore inode
 * fork 'ifp'.  'count' new items are inserted at index 'idx'.
 */
void
xfs_iext_insert(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_extnum_t	idx,		/* starting index of new items */
	xfs_extnum_t	count,		/* number of inserted items */
	xfs_bmbt_irec_t	*new,		/* items to insert */
	int		state)		/* type of extent conversion */
{
	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
	xfs_extnum_t	i;		/* extent record index */

	trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_);

	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	xfs_iext_add(ifp, idx, count);
	for (i = idx; i < idx + count; i++, new++)
		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, i), new);
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be increased. The ext_diff parameter stores the
 * number of new extents being added and the idx parameter contains
 * the extent index where the new extents will be added. If the new
 * extents are being appended, then we just need to (re)allocate and
 * initialize the space. Otherwise, if the new extents are being
 * inserted into the middle of the existing entries, a bit more work
 * is required to make room for the new extents to be inserted. The
 * caller is responsible for filling in the new extent entries upon
 * return.
 */
void
xfs_iext_add(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin adding exts */
	int		ext_diff)	/* number of extents to add */
{
	int		byte_diff;	/* new bytes being added */
	int		new_size;	/* size of extents after adding */
	xfs_extnum_t	nextents;	/* number of extents in file */

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT((idx >= 0) && (idx <= nextents));
	byte_diff = ext_diff * sizeof(xfs_bmbt_rec_t);
	new_size = ifp->if_bytes + byte_diff;
	/*
	 * If the new number of extents (nextents + ext_diff)
	 * fits inside the inode, then continue to use the inline
	 * extent buffer.
	 */
	if (nextents + ext_diff <= XFS_INLINE_EXTS) {
		if (idx < nextents) {
			memmove(&ifp->if_u2.if_inline_ext[idx + ext_diff],
				&ifp->if_u2.if_inline_ext[idx],
				(nextents - idx) * sizeof(xfs_bmbt_rec_t));
			memset(&ifp->if_u2.if_inline_ext[idx], 0, byte_diff);
		}
		ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
		ifp->if_real_bytes = 0;
	}
	/*
	 * Otherwise use a linear (direct) extent list.
	 * If the extents are currently inside the inode,
	 * xfs_iext_realloc_direct will switch us from
	 * inline to direct extent allocation mode.
	 */
	else if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
		xfs_iext_realloc_direct(ifp, new_size);
		if (idx < nextents) {
			memmove(&ifp->if_u1.if_extents[idx + ext_diff],
				&ifp->if_u1.if_extents[idx],
				(nextents - idx) * sizeof(xfs_bmbt_rec_t));
			memset(&ifp->if_u1.if_extents[idx], 0, byte_diff);
		}
	}
	/* Indirection array */
	else {
		xfs_ext_irec_t	*erp;
		int		erp_idx = 0;
		int		page_idx = idx;

		ASSERT(nextents + ext_diff > XFS_LINEAR_EXTS);
		if (ifp->if_flags & XFS_IFEXTIREC) {
			erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 1);
		} else {
			xfs_iext_irec_init(ifp);
			ASSERT(ifp->if_flags & XFS_IFEXTIREC);
			erp = ifp->if_u1.if_ext_irec;
		}
		/* Extents fit in target extent page */
		if (erp && erp->er_extcount + ext_diff <= XFS_LINEAR_EXTS) {
			if (page_idx < erp->er_extcount) {
				memmove(&erp->er_extbuf[page_idx + ext_diff],
					&erp->er_extbuf[page_idx],
					(erp->er_extcount - page_idx) *
					sizeof(xfs_bmbt_rec_t));
				memset(&erp->er_extbuf[page_idx], 0, byte_diff);
			}
			erp->er_extcount += ext_diff;
			xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		}
		/* Insert a new extent page */
		else if (erp) {
			xfs_iext_add_indirect_multi(ifp,
				erp_idx, page_idx, ext_diff);
		}
		/*
		 * If extent(s) are being appended to the last page in
		 * the indirection array and the new extent(s) don't fit
		 * in the page, then erp is NULL and erp_idx is set to
		 * the next index needed in the indirection array.
		 */
		else {
			uint	count = ext_diff;

			while (count) {
				erp = xfs_iext_irec_new(ifp, erp_idx);
				erp->er_extcount = min(count, XFS_LINEAR_EXTS);
				count -= erp->er_extcount;
				if (count)
					erp_idx++;
			}
		}
	}
	ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being added to the indirection
 * array and the new extents do not fit in the target extent list. The
 * erp_idx parameter contains the irec index for the target extent list
 * in the indirection array, and the idx parameter contains the extent
 * index within the list. The number of extents being added is stored
 * in the count parameter.
 *
 *    |-------|   |-------|
 *    |       |   |       |    idx - number of extents before idx
 *    |  idx  |   | count |
 *    |       |   |       |    count - number of extents being inserted at idx
 *    |-------|   |-------|
 *    | count |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_add_indirect_multi(
	xfs_ifork_t	*ifp,			/* inode fork pointer */
	int		erp_idx,		/* target extent irec index */
	xfs_extnum_t	idx,			/* index within target list */
	int		count)			/* new extents being added */
{
	int		byte_diff;		/* new bytes being added */
	xfs_ext_irec_t	*erp;			/* pointer to irec entry */
	xfs_extnum_t	ext_diff;		/* number of extents to add */
	xfs_extnum_t	ext_cnt;		/* new extents still needed */
	xfs_extnum_t	nex2;			/* extents after idx + count */
	xfs_bmbt_rec_t	*nex2_ep = NULL;	/* temp list for nex2 extents */
	int		nlists;			/* number of irec's (lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	erp = &ifp->if_u1.if_ext_irec[erp_idx];
	nex2 = erp->er_extcount - idx;
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

	/*
	 * Save second part of target extent list
	 * (all extents past */
	if (nex2) {
		byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
		nex2_ep = (xfs_bmbt_rec_t *) kmem_alloc(byte_diff, KM_NOFS);
		memmove(nex2_ep, &erp->er_extbuf[idx], byte_diff);
		erp->er_extcount -= nex2;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -nex2);
		memset(&erp->er_extbuf[idx], 0, byte_diff);
	}

	/*
	 * Add the new extents to the end of the target
	 * list, then allocate new irec record(s) and
	 * extent buffer(s) as needed to store the rest
	 * of the new extents.
	 */
	ext_cnt = count;
	ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS - erp->er_extcount);
	if (ext_diff) {
		erp->er_extcount += ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		ext_cnt -= ext_diff;
	}
	while (ext_cnt) {
		erp_idx++;
		erp = xfs_iext_irec_new(ifp, erp_idx);
		ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS);
		erp->er_extcount = ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		ext_cnt -= ext_diff;
	}

	/* Add nex2 extents back to indirection array */
	if (nex2) {
		xfs_extnum_t	ext_avail;
		int		i;

		byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
		ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
		i = 0;
		/*
		 * If nex2 extents fit in the current page, append
		 * nex2_ep after the new extents.
		 */
		if (nex2 <= ext_avail) {
			i = erp->er_extcount;
		}
		/*
		 * Otherwise, check if space is available in the
		 * next page.
		 */
		else if ((erp_idx < nlists - 1) &&
			 (nex2 <= (ext_avail = XFS_LINEAR_EXTS -
			  ifp->if_u1.if_ext_irec[erp_idx+1].er_extcount))) {
			erp_idx++;
			erp++;
			/* Create a hole for nex2 extents */
			memmove(&erp->er_extbuf[nex2], erp->er_extbuf,
				erp->er_extcount * sizeof(xfs_bmbt_rec_t));
		}
		/*
		 * Final choice, create a new extent page for
		 * nex2 extents.
		 */
		else {
			erp_idx++;
			erp = xfs_iext_irec_new(ifp, erp_idx);
		}
		memmove(&erp->er_extbuf[i], nex2_ep, byte_diff);
		kmem_free(nex2_ep);
		erp->er_extcount += nex2;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, nex2);
	}
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be decreased. The ext_diff parameter stores the
 * number of extents to be removed and the idx parameter contains
 * the extent index where the extents will be removed from.
 *
 * If the amount of space needed has decreased below the linear
 * limit, XFS_IEXT_BUFSZ, then switch to using the contiguous
 * extent array.  Otherwise, use kmem_realloc() to adjust the
 * size to what is needed.
 */
void
xfs_iext_remove(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff,	/* number of extents to remove */
	int		state)		/* type of extent conversion */
{
	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		new_size;	/* size of extents after removal */

	trace_xfs_iext_remove(ip, idx, state, _RET_IP_);

	ASSERT(ext_diff > 0);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	new_size = (nextents - ext_diff) * sizeof(xfs_bmbt_rec_t);

	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	} else if (ifp->if_flags & XFS_IFEXTIREC) {
		xfs_iext_remove_indirect(ifp, idx, ext_diff);
	} else if (ifp->if_real_bytes) {
		xfs_iext_remove_direct(ifp, idx, ext_diff);
	} else {
		xfs_iext_remove_inline(ifp, idx, ext_diff);
	}
	ifp->if_bytes = new_size;
}

/*
 * This removes ext_diff extents from the inline buffer, beginning
 * at extent index idx.
 */
void
xfs_iext_remove_inline(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff)	/* number of extents to remove */
{
	int		nextents;	/* number of extents in file */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	ASSERT(idx < XFS_INLINE_EXTS);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(((nextents - ext_diff) > 0) &&
		(nextents - ext_diff) < XFS_INLINE_EXTS);

	if (idx + ext_diff < nextents) {
		memmove(&ifp->if_u2.if_inline_ext[idx],
			&ifp->if_u2.if_inline_ext[idx + ext_diff],
			(nextents - (idx + ext_diff)) *
			 sizeof(xfs_bmbt_rec_t));
		memset(&ifp->if_u2.if_inline_ext[nextents - ext_diff],
			0, ext_diff * sizeof(xfs_bmbt_rec_t));
	} else {
		memset(&ifp->if_u2.if_inline_ext[idx], 0,
			ext_diff * sizeof(xfs_bmbt_rec_t));
	}
}

/*
 * This removes ext_diff extents from a linear (direct) extent list,
 * beginning at extent index idx. If the extents are being removed
 * from the end of the list (ie. truncate) then we just need to re-
 * allocate the list to remove the extra space. Otherwise, if the
 * extents are being removed from the middle of the existing extent
 * entries, then we first need to move the extent records beginning
 * at idx + ext_diff up in the list to overwrite the records being
 * removed, then remove the extra space via kmem_realloc.
 */
void
xfs_iext_remove_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff)	/* number of extents to remove */
{
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		new_size;	/* size of extents after removal */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	new_size = ifp->if_bytes -
		(ext_diff * sizeof(xfs_bmbt_rec_t));
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (new_size == 0) {
		xfs_iext_destroy(ifp);
		return;
	}
	/* Move extents up in the list (if needed) */
	if (idx + ext_diff < nextents) {
		memmove(&ifp->if_u1.if_extents[idx],
			&ifp->if_u1.if_extents[idx + ext_diff],
			(nextents - (idx + ext_diff)) *
			 sizeof(xfs_bmbt_rec_t));
	}
	memset(&ifp->if_u1.if_extents[nextents - ext_diff],
		0, ext_diff * sizeof(xfs_bmbt_rec_t));
	/*
	 * Reallocate the direct extent list. If the extents
	 * will fit inside the inode then xfs_iext_realloc_direct
	 * will switch from direct to inline extent allocation
	 * mode for us.
	 */
	xfs_iext_realloc_direct(ifp, new_size);
	ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being removed from the
 * indirection array and the extents being removed span multiple extent
 * buffers. The idx parameter contains the file extent index where we
 * want to begin removing extents, and the count parameter contains
 * how many extents need to be removed.
 *
 *    |-------|   |-------|
 *    | nex1  |   |       |    nex1 - number of extents before idx
 *    |-------|   | count |
 *    |       |   |       |    count - number of extents being removed at idx
 *    | count |   |-------|
 *    |       |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_remove_indirect(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing extents */
	int		count)		/* number of extents to remove */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		erp_idx = 0;	/* indirection array index */
	xfs_extnum_t	ext_cnt;	/* extents left to remove */
	xfs_extnum_t	ext_diff;	/* extents to remove in current list */
	xfs_extnum_t	nex1;		/* number of extents before idx */
	xfs_extnum_t	nex2;		/* extents after idx + count */
	int		page_idx = idx;	/* index in target extent list */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	erp = xfs_iext_idx_to_irec(ifp,  &page_idx, &erp_idx, 0);
	ASSERT(erp != NULL);
	nex1 = page_idx;
	ext_cnt = count;
	while (ext_cnt) {
		nex2 = MAX((erp->er_extcount - (nex1 + ext_cnt)), 0);
		ext_diff = MIN(ext_cnt, (erp->er_extcount - nex1));
		/*
		 * Check for deletion of entire list;
		 * xfs_iext_irec_remove() updates extent offsets.
		 */
		if (ext_diff == erp->er_extcount) {
			xfs_iext_irec_remove(ifp, erp_idx);
			ext_cnt -= ext_diff;
			nex1 = 0;
			if (ext_cnt) {
				ASSERT(erp_idx < ifp->if_real_bytes /
					XFS_IEXT_BUFSZ);
				erp = &ifp->if_u1.if_ext_irec[erp_idx];
				nex1 = 0;
				continue;
			} else {
				break;
			}
		}
		/* Move extents up (if needed) */
		if (nex2) {
			memmove(&erp->er_extbuf[nex1],
				&erp->er_extbuf[nex1 + ext_diff],
				nex2 * sizeof(xfs_bmbt_rec_t));
		}
		/* Zero out rest of page */
		memset(&erp->er_extbuf[nex1 + nex2], 0, (XFS_IEXT_BUFSZ -
			((nex1 + nex2) * sizeof(xfs_bmbt_rec_t))));
		/* Update remaining counters */
		erp->er_extcount -= ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -ext_diff);
		ext_cnt -= ext_diff;
		nex1 = 0;
		erp_idx++;
		erp++;
	}
	ifp->if_bytes -= count * sizeof(xfs_bmbt_rec_t);
	xfs_iext_irec_compact(ifp);
}

/*
 * Create, destroy, or resize a linear (direct) block of extents.
 */
void
xfs_iext_realloc_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* new size of extents after adding */
{
	int		rnew_size;	/* real new size of extents */

	rnew_size = new_size;

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC) ||
		((new_size >= 0) && (new_size <= XFS_IEXT_BUFSZ) &&
		 (new_size != ifp->if_real_bytes)));

	/* Free extent records */
	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	}
	/* Resize direct extent list and zero any new bytes */
	else if (ifp->if_real_bytes) {
		/* Check if extents will fit inside the inode */
		if (new_size <= XFS_INLINE_EXTS * sizeof(xfs_bmbt_rec_t)) {
			xfs_iext_direct_to_inline(ifp, new_size /
				(uint)sizeof(xfs_bmbt_rec_t));
			ifp->if_bytes = new_size;
			return;
		}
		if (!is_power_of_2(new_size)){
			rnew_size = roundup_pow_of_two(new_size);
		}
		if (rnew_size != ifp->if_real_bytes) {
			ifp->if_u1.if_extents =
				kmem_realloc(ifp->if_u1.if_extents,
						rnew_size, KM_NOFS);
		}
		if (rnew_size > ifp->if_real_bytes) {
			memset(&ifp->if_u1.if_extents[ifp->if_bytes /
				(uint)sizeof(xfs_bmbt_rec_t)], 0,
				rnew_size - ifp->if_real_bytes);
		}
	}
	/* Switch from the inline extent buffer to a direct extent list */
	else {
		if (!is_power_of_2(new_size)) {
			rnew_size = roundup_pow_of_two(new_size);
		}
		xfs_iext_inline_to_direct(ifp, rnew_size);
	}
	ifp->if_real_bytes = rnew_size;
	ifp->if_bytes = new_size;
}

/*
 * Switch from linear (direct) extent records to inline buffer.
 */
void
xfs_iext_direct_to_inline(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	nextents)	/* number of extents in file */
{
	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	ASSERT(nextents <= XFS_INLINE_EXTS);
	/*
	 * The inline buffer was zeroed when we switched
	 * from inline to direct extent allocation mode,
	 * so we don't need to clear it here.
	 */
	memcpy(ifp->if_u2.if_inline_ext, ifp->if_u1.if_extents,
		nextents * sizeof(xfs_bmbt_rec_t));
	kmem_free(ifp->if_u1.if_extents);
	ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
	ifp->if_real_bytes = 0;
}

/*
 * Switch from inline buffer to linear (direct) extent records.
 * new_size should already be rounded up to the next power of 2
 * by the caller (when appropriate), so use new_size as it is.
 * However, since new_size may be rounded up, we can't update
 * if_bytes here. It is the caller's responsibility to update
 * if_bytes upon return.
 */
void
xfs_iext_inline_to_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* number of extents in file */
{
	ifp->if_u1.if_extents = kmem_alloc(new_size, KM_NOFS);
	memset(ifp->if_u1.if_extents, 0, new_size);
	if (ifp->if_bytes) {
		memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
			ifp->if_bytes);
		memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
			sizeof(xfs_bmbt_rec_t));
	}
	ifp->if_real_bytes = new_size;
}

/*
 * Resize an extent indirection array to new_size bytes.
 */
STATIC void
xfs_iext_realloc_indirect(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* new indirection array size */
{
	int		nlists;		/* number of irec's (ex lists) */
	int		size;		/* current indirection array size */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	size = nlists * sizeof(xfs_ext_irec_t);
	ASSERT(ifp->if_real_bytes);
	ASSERT((new_size >= 0) && (new_size != size));
	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	} else {
		ifp->if_u1.if_ext_irec =
			kmem_realloc(ifp->if_u1.if_ext_irec, new_size, KM_NOFS);
	}
}

/*
 * Switch from indirection array to linear (direct) extent allocations.
 */
STATIC void
xfs_iext_indirect_to_direct(
	 xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_bmbt_rec_host_t *ep;	/* extent record pointer */
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		size;		/* size of file extents */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(nextents <= XFS_LINEAR_EXTS);
	size = nextents * sizeof(xfs_bmbt_rec_t);

	xfs_iext_irec_compact_pages(ifp);
	ASSERT(ifp->if_real_bytes == XFS_IEXT_BUFSZ);

	ep = ifp->if_u1.if_ext_irec->er_extbuf;
	kmem_free(ifp->if_u1.if_ext_irec);
	ifp->if_flags &= ~XFS_IFEXTIREC;
	ifp->if_u1.if_extents = ep;
	ifp->if_bytes = size;
	if (nextents < XFS_LINEAR_EXTS) {
		xfs_iext_realloc_direct(ifp, size);
	}
}

/*
 * Free incore file extents.
 */
void
xfs_iext_destroy(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	if (ifp->if_flags & XFS_IFEXTIREC) {
		int	erp_idx;
		int	nlists;

		nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
		for (erp_idx = nlists - 1; erp_idx >= 0 ; erp_idx--) {
			xfs_iext_irec_remove(ifp, erp_idx);
		}
		ifp->if_flags &= ~XFS_IFEXTIREC;
	} else if (ifp->if_real_bytes) {
		kmem_free(ifp->if_u1.if_extents);
	} else if (ifp->if_bytes) {
		memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
			sizeof(xfs_bmbt_rec_t));
	}
	ifp->if_u1.if_extents = NULL;
	ifp->if_real_bytes = 0;
	ifp->if_bytes = 0;
}

/*
 * Return a pointer to the extent record for file system block bno.
 */
xfs_bmbt_rec_host_t *			/* pointer to found extent record */
xfs_iext_bno_to_ext(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fileoff_t	bno,		/* block number to search for */
	xfs_extnum_t	*idxp)		/* index of target extent */
{
	xfs_bmbt_rec_host_t *base;	/* pointer to first extent */
	xfs_filblks_t	blockcount = 0;	/* number of blocks in extent */
	xfs_bmbt_rec_host_t *ep = NULL;	/* pointer to target extent */
	xfs_ext_irec_t	*erp = NULL;	/* indirection array pointer */
	int		high;		/* upper boundary in search */
	xfs_extnum_t	idx = 0;	/* index of target extent */
	int		low;		/* lower boundary in search */
	xfs_extnum_t	nextents;	/* number of file extents */
	xfs_fileoff_t	startoff = 0;	/* start offset of extent */

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (nextents == 0) {
		*idxp = 0;
		return NULL;
	}
	low = 0;
	if (ifp->if_flags & XFS_IFEXTIREC) {
		/* Find target extent list */
		int	erp_idx = 0;
		erp = xfs_iext_bno_to_irec(ifp, bno, &erp_idx);
		base = erp->er_extbuf;
		high = erp->er_extcount - 1;
	} else {
		base = ifp->if_u1.if_extents;
		high = nextents - 1;
	}
	/* Binary search extent records */
	while (low <= high) {
		idx = (low + high) >> 1;
		ep = base + idx;
		startoff = xfs_bmbt_get_startoff(ep);
		blockcount = xfs_bmbt_get_blockcount(ep);
		if (bno < startoff) {
			high = idx - 1;
		} else if (bno >= startoff + blockcount) {
			low = idx + 1;
		} else {
			/* Convert back to file-based extent index */
			if (ifp->if_flags & XFS_IFEXTIREC) {
				idx += erp->er_extoff;
			}
			*idxp = idx;
			return ep;
		}
	}
	/* Convert back to file-based extent index */
	if (ifp->if_flags & XFS_IFEXTIREC) {
		idx += erp->er_extoff;
	}
	if (bno >= startoff + blockcount) {
		if (++idx == nextents) {
			ep = NULL;
		} else {
			ep = xfs_iext_get_ext(ifp, idx);
		}
	}
	*idxp = idx;
	return ep;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record for filesystem block bno. Store the index of the
 * target irec in *erp_idxp.
 */
xfs_ext_irec_t *			/* pointer to found extent record */
xfs_iext_bno_to_irec(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fileoff_t	bno,		/* block number to search for */
	int		*erp_idxp)	/* irec index of target ext list */
{
	xfs_ext_irec_t	*erp = NULL;	/* indirection array pointer */
	xfs_ext_irec_t	*erp_next;	/* next indirection array entry */
	int		erp_idx;	/* indirection array index */
	int		nlists;		/* number of extent irec's (lists) */
	int		high;		/* binary search upper limit */
	int		low;		/* binary search lower limit */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp_idx = 0;
	low = 0;
	high = nlists - 1;
	while (low <= high) {
		erp_idx = (low + high) >> 1;
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		erp_next = erp_idx < nlists - 1 ? erp + 1 : NULL;
		if (bno < xfs_bmbt_get_startoff(erp->er_extbuf)) {
			high = erp_idx - 1;
		} else if (erp_next && bno >=
			   xfs_bmbt_get_startoff(erp_next->er_extbuf)) {
			low = erp_idx + 1;
		} else {
			break;
		}
	}
	*erp_idxp = erp_idx;
	return erp;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record at file extent index *idxp. Store the index of the
 * target irec in *erp_idxp and store the page index of the target
 * extent record in *idxp.
 */
xfs_ext_irec_t *
xfs_iext_idx_to_irec(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	*idxp,		/* extent index (file -> page) */
	int		*erp_idxp,	/* pointer to target irec */
	int		realloc)	/* new bytes were just added */
{
	xfs_ext_irec_t	*prev;		/* pointer to previous irec */
	xfs_ext_irec_t	*erp = NULL;	/* pointer to current irec */
	int		erp_idx;	/* indirection array index */
	int		nlists;		/* number of irec's (ex lists) */
	int		high;		/* binary search upper limit */
	int		low;		/* binary search lower limit */
	xfs_extnum_t	page_idx = *idxp; /* extent index in target list */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	ASSERT(page_idx >= 0);
	ASSERT(page_idx <= ifp->if_bytes / sizeof(xfs_bmbt_rec_t));
	ASSERT(page_idx < ifp->if_bytes / sizeof(xfs_bmbt_rec_t) || realloc);

	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp_idx = 0;
	low = 0;
	high = nlists - 1;

	/* Binary search extent irec's */
	while (low <= high) {
		erp_idx = (low + high) >> 1;
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		prev = erp_idx > 0 ? erp - 1 : NULL;
		if (page_idx < erp->er_extoff || (page_idx == erp->er_extoff &&
		     realloc && prev && prev->er_extcount < XFS_LINEAR_EXTS)) {
			high = erp_idx - 1;
		} else if (page_idx > erp->er_extoff + erp->er_extcount ||
			   (page_idx == erp->er_extoff + erp->er_extcount &&
			    !realloc)) {
			low = erp_idx + 1;
		} else if (page_idx == erp->er_extoff + erp->er_extcount &&
			   erp->er_extcount == XFS_LINEAR_EXTS) {
			ASSERT(realloc);
			page_idx = 0;
			erp_idx++;
			erp = erp_idx < nlists ? erp + 1 : NULL;
			break;
		} else {
			page_idx -= erp->er_extoff;
			break;
		}
	}
	*idxp = page_idx;
	*erp_idxp = erp_idx;
	return erp;
}

/*
 * Allocate and initialize an indirection array once the space needed
 * for incore extents increases above XFS_IEXT_BUFSZ.
 */
void
xfs_iext_irec_init(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	xfs_extnum_t	nextents;	/* number of extents in file */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(nextents <= XFS_LINEAR_EXTS);

	erp = kmem_alloc(sizeof(xfs_ext_irec_t), KM_NOFS);

	if (nextents == 0) {
		ifp->if_u1.if_extents = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
	} else if (!ifp->if_real_bytes) {
		xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
	} else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
		xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
	}
	erp->er_extbuf = ifp->if_u1.if_extents;
	erp->er_extcount = nextents;
	erp->er_extoff = 0;

	ifp->if_flags |= XFS_IFEXTIREC;
	ifp->if_real_bytes = XFS_IEXT_BUFSZ;
	ifp->if_bytes = nextents * sizeof(xfs_bmbt_rec_t);
	ifp->if_u1.if_ext_irec = erp;

	return;
}

/*
 * Allocate and initialize a new entry in the indirection array.
 */
xfs_ext_irec_t *
xfs_iext_irec_new(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx)	/* index for new irec */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

	/* Resize indirection array */
	xfs_iext_realloc_indirect(ifp, ++nlists *
				  sizeof(xfs_ext_irec_t));
	/*
	 * Move records down in the array so the
	 * new page can use erp_idx.
	 */
	erp = ifp->if_u1.if_ext_irec;
	for (i = nlists - 1; i > erp_idx; i--) {
		memmove(&erp[i], &erp[i-1], sizeof(xfs_ext_irec_t));
	}
	ASSERT(i == erp_idx);

	/* Initialize new extent record */
	erp = ifp->if_u1.if_ext_irec;
	erp[erp_idx].er_extbuf = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
	ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
	memset(erp[erp_idx].er_extbuf, 0, XFS_IEXT_BUFSZ);
	erp[erp_idx].er_extcount = 0;
	erp[erp_idx].er_extoff = erp_idx > 0 ?
		erp[erp_idx-1].er_extoff + erp[erp_idx-1].er_extcount : 0;
	return (&erp[erp_idx]);
}

/*
 * Remove a record from the indirection array.
 */
void
xfs_iext_irec_remove(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx)	/* irec index to remove */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp = &ifp->if_u1.if_ext_irec[erp_idx];
	if (erp->er_extbuf) {
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1,
			-erp->er_extcount);
		kmem_free(erp->er_extbuf);
	}
	/* Compact extent records */
	erp = ifp->if_u1.if_ext_irec;
	for (i = erp_idx; i < nlists - 1; i++) {
		memmove(&erp[i], &erp[i+1], sizeof(xfs_ext_irec_t));
	}
	/*
	 * Manually free the last extent record from the indirection
	 * array.  A call to xfs_iext_realloc_indirect() with a size
	 * of zero would result in a call to xfs_iext_destroy() which
	 * would in turn call this function again, creating a nasty
	 * infinite loop.
	 */
	if (--nlists) {
		xfs_iext_realloc_indirect(ifp,
			nlists * sizeof(xfs_ext_irec_t));
	} else {
		kmem_free(ifp->if_u1.if_ext_irec);
	}
	ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
}

/*
 * This is called to clean up large amounts of unused memory allocated
 * by the indirection array.  Before compacting anything though, verify
 * that the indirection array is still needed and switch back to the
 * linear extent list (or even the inline buffer) if possible.  The
 * compaction policy is as follows:
 *
 *    Full Compaction: Extents fit into a single page (or inline buffer)
 * Partial Compaction: Extents occupy less than 50% of allocated space
 *      No Compaction: Extents occupy at least 50% of allocated space
 */
void
xfs_iext_irec_compact(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (nextents == 0) {
		xfs_iext_destroy(ifp);
	} else if (nextents <= XFS_INLINE_EXTS) {
		xfs_iext_indirect_to_direct(ifp);
		xfs_iext_direct_to_inline(ifp, nextents);
	} else if (nextents <= XFS_LINEAR_EXTS) {
		xfs_iext_indirect_to_direct(ifp);
	} else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
		xfs_iext_irec_compact_pages(ifp);
	}
}

/*
 * Combine extents from neighboring extent pages.
 */
void
xfs_iext_irec_compact_pages(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_ext_irec_t	*erp, *erp_next;/* pointers to irec entries */
	int		erp_idx = 0;	/* indirection array index */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	while (erp_idx < nlists - 1) {
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		erp_next = erp + 1;
		if (erp_next->er_extcount <=
		    (XFS_LINEAR_EXTS - erp->er_extcount)) {
			memcpy(&erp->er_extbuf[erp->er_extcount],
				erp_next->er_extbuf, erp_next->er_extcount *
				sizeof(xfs_bmbt_rec_t));
			erp->er_extcount += erp_next->er_extcount;
			/*
			 * Free page before removing extent record
			 * so er_extoffs don't get modified in
			 * xfs_iext_irec_remove.
			 */
			kmem_free(erp_next->er_extbuf);
			erp_next->er_extbuf = NULL;
			xfs_iext_irec_remove(ifp, erp_idx + 1);
			nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
		} else {
			erp_idx++;
		}
	}
}

/*
 * This is called to update the er_extoff field in the indirection
 * array when extents have been added or removed from one of the
 * extent lists. erp_idx contains the irec index to begin updating
 * at and ext_diff contains the number of extents that were added
 * or removed.
 */
void
xfs_iext_irec_update_extoffs(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx,	/* irec index to update */
	int		ext_diff)	/* number of new extents */
{
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	for (i = erp_idx; i < nlists; i++) {
		ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
	}
}