aboutsummaryrefslogtreecommitdiffstats
path: root/fs/dquot.c
blob: 5bdc4b2a872a41818adac58bc7e2ece95ee956ec (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
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
/*
 * Implementation of the diskquota system for the LINUX operating system. QUOTA
 * is implemented using the BSD system call interface as the means of
 * communication with the user level. This file contains the generic routines
 * called by the different filesystems on allocation of an inode or block.
 * These routines take care of the administration needed to have a consistent
 * diskquota tracking system. The ideas of both user and group quotas are based
 * on the Melbourne quota system as used on BSD derived systems. The internal
 * implementation is based on one of the several variants of the LINUX
 * inode-subsystem with added complexity of the diskquota system.
 * 
 * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
 * 
 * Author:	Marco van Wieringen <mvw@planets.elm.net>
 *
 * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
 *
 *		Revised list management to avoid races
 *		-- Bill Hawes, <whawes@star.net>, 9/98
 *
 *		Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
 *		As the consequence the locking was moved from dquot_decr_...(),
 *		dquot_incr_...() to calling functions.
 *		invalidate_dquots() now writes modified dquots.
 *		Serialized quota_off() and quota_on() for mount point.
 *		Fixed a few bugs in grow_dquots().
 *		Fixed deadlock in write_dquot() - we no longer account quotas on
 *		quota files
 *		remove_dquot_ref() moved to inode.c - it now traverses through inodes
 *		add_dquot_ref() restarts after blocking
 *		Added check for bogus uid and fixed check for group in quotactl.
 *		Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
 *
 *		Used struct list_head instead of own list struct
 *		Invalidation of referenced dquots is no longer possible
 *		Improved free_dquots list management
 *		Quota and i_blocks are now updated in one place to avoid races
 *		Warnings are now delayed so we won't block in critical section
 *		Write updated not to require dquot lock
 *		Jan Kara, <jack@suse.cz>, 9/2000
 *
 *		Added dynamic quota structure allocation
 *		Jan Kara <jack@suse.cz> 12/2000
 *
 *		Rewritten quota interface. Implemented new quota format and
 *		formats registering.
 *		Jan Kara, <jack@suse.cz>, 2001,2002
 *
 *		New SMP locking.
 *		Jan Kara, <jack@suse.cz>, 10/2002
 *
 *		Added journalled quota support, fix lock inversion problems
 *		Jan Kara, <jack@suse.cz>, 2003,2004
 *
 * (C) Copyright 1994 - 1997 Marco van Wieringen 
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/kmod.h>
#include <linux/namei.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/writeback.h> /* for inode_lock, oddly enough.. */

#include <asm/uaccess.h>

#define __DQUOT_PARANOIA

/*
 * There are two quota SMP locks. dq_list_lock protects all lists with quotas
 * and quota formats and also dqstats structure containing statistics about the
 * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
 * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
 * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
 * in inode_add_bytes() and inode_sub_bytes().
 *
 * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
 *
 * Note that some things (eg. sb pointer, type, id) doesn't change during
 * the life of the dquot structure and so needn't to be protected by a lock
 *
 * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
 * operation is just reading pointers from inode (or not using them at all) the
 * read lock is enough. If pointers are altered function must hold write lock
 * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
 * for altering the flag i_mutex is also needed).  If operation is holding
 * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
 * dqonoff_mutex.
 * This locking assures that:
 *   a) update/access to dquot pointers in inode is serialized
 *   b) everyone is guarded against invalidate_dquots()
 *
 * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
 * from inodes (dquot_alloc_space() and such don't check the dq_lock).
 * Currently dquot is locked only when it is being read to memory (or space for
 * it is being allocated) on the first dqget() and when it is being released on
 * the last dqput(). The allocation and release oparations are serialized by
 * the dq_lock and by checking the use count in dquot_release().  Write
 * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
 * spinlock to internal buffers before writing.
 *
 * Lock ordering (including related VFS locks) is the following:
 *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
 *   dqio_mutex
 * i_mutex on quota files is special (it's below dqio_mutex)
 */

static DEFINE_SPINLOCK(dq_list_lock);
DEFINE_SPINLOCK(dq_data_lock);

static char *quotatypes[] = INITQFNAMES;
static struct quota_format_type *quota_formats;	/* List of registered formats */
static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;

/* SLAB cache for dquot structures */
static struct kmem_cache *dquot_cachep;

int register_quota_format(struct quota_format_type *fmt)
{
	spin_lock(&dq_list_lock);
	fmt->qf_next = quota_formats;
	quota_formats = fmt;
	spin_unlock(&dq_list_lock);
	return 0;
}

void unregister_quota_format(struct quota_format_type *fmt)
{
	struct quota_format_type **actqf;

	spin_lock(&dq_list_lock);
	for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
	if (*actqf)
		*actqf = (*actqf)->qf_next;
	spin_unlock(&dq_list_lock);
}

static struct quota_format_type *find_quota_format(int id)
{
	struct quota_format_type *actqf;

	spin_lock(&dq_list_lock);
	for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
	if (!actqf || !try_module_get(actqf->qf_owner)) {
		int qm;

		spin_unlock(&dq_list_lock);
		
		for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
		if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
			return NULL;

		spin_lock(&dq_list_lock);
		for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
		if (actqf && !try_module_get(actqf->qf_owner))
			actqf = NULL;
	}
	spin_unlock(&dq_list_lock);
	return actqf;
}

static void put_quota_format(struct quota_format_type *fmt)
{
	module_put(fmt->qf_owner);
}

/*
 * Dquot List Management:
 * The quota code uses three lists for dquot management: the inuse_list,
 * free_dquots, and dquot_hash[] array. A single dquot structure may be
 * on all three lists, depending on its current state.
 *
 * All dquots are placed to the end of inuse_list when first created, and this
 * list is used for invalidate operation, which must look at every dquot.
 *
 * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 * and this list is searched whenever we need an available dquot.  Dquots are
 * removed from the list as soon as they are used again, and
 * dqstats.free_dquots gives the number of dquots on the list. When
 * dquot is invalidated it's completely released from memory.
 *
 * Dquots with a specific identity (device, type and id) are placed on
 * one of the dquot_hash[] hash chains. The provides an efficient search
 * mechanism to locate a specific dquot.
 */

static LIST_HEAD(inuse_list);
static LIST_HEAD(free_dquots);
static unsigned int dq_hash_bits, dq_hash_mask;
static struct hlist_head *dquot_hash;

struct dqstats dqstats;

static void dqput(struct dquot *dquot);

static inline unsigned int
hashfn(const struct super_block *sb, unsigned int id, int type)
{
	unsigned long tmp;

	tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
	return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
}

/*
 * Following list functions expect dq_list_lock to be held
 */
static inline void insert_dquot_hash(struct dquot *dquot)
{
	struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
	hlist_add_head(&dquot->dq_hash, head);
}

static inline void remove_dquot_hash(struct dquot *dquot)
{
	hlist_del_init(&dquot->dq_hash);
}

static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
{
	struct hlist_node *node;
	struct dquot *dquot;

	hlist_for_each (node, dquot_hash+hashent) {
		dquot = hlist_entry(node, struct dquot, dq_hash);
		if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
			return dquot;
	}
	return NODQUOT;
}

/* Add a dquot to the tail of the free list */
static inline void put_dquot_last(struct dquot *dquot)
{
	list_add_tail(&dquot->dq_free, &free_dquots);
	dqstats.free_dquots++;
}

static inline void remove_free_dquot(struct dquot *dquot)
{
	if (list_empty(&dquot->dq_free))
		return;
	list_del_init(&dquot->dq_free);
	dqstats.free_dquots--;
}

static inline void put_inuse(struct dquot *dquot)
{
	/* We add to the back of inuse list so we don't have to restart
	 * when traversing this list and we block */
	list_add_tail(&dquot->dq_inuse, &inuse_list);
	dqstats.allocated_dquots++;
}

static inline void remove_inuse(struct dquot *dquot)
{
	dqstats.allocated_dquots--;
	list_del(&dquot->dq_inuse);
}
/*
 * End of list functions needing dq_list_lock
 */

static void wait_on_dquot(struct dquot *dquot)
{
	mutex_lock(&dquot->dq_lock);
	mutex_unlock(&dquot->dq_lock);
}

#define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))

int dquot_mark_dquot_dirty(struct dquot *dquot)
{
	spin_lock(&dq_list_lock);
	if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
		list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
				info[dquot->dq_type].dqi_dirty_list);
	spin_unlock(&dq_list_lock);
	return 0;
}

/* This function needs dq_list_lock */
static inline int clear_dquot_dirty(struct dquot *dquot)
{
	if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
		return 0;
	list_del_init(&dquot->dq_dirty);
	return 1;
}

void mark_info_dirty(struct super_block *sb, int type)
{
	set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
}
EXPORT_SYMBOL(mark_info_dirty);

/*
 *	Read dquot from disk and alloc space for it
 */

int dquot_acquire(struct dquot *dquot)
{
	int ret = 0, ret2 = 0;
	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

	mutex_lock(&dquot->dq_lock);
	mutex_lock(&dqopt->dqio_mutex);
	if (!test_bit(DQ_READ_B, &dquot->dq_flags))
		ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
	if (ret < 0)
		goto out_iolock;
	set_bit(DQ_READ_B, &dquot->dq_flags);
	/* Instantiate dquot if needed */
	if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
		ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
		/* Write the info if needed */
		if (info_dirty(&dqopt->info[dquot->dq_type]))
			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
		if (ret < 0)
			goto out_iolock;
		if (ret2 < 0) {
			ret = ret2;
			goto out_iolock;
		}
	}
	set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_iolock:
	mutex_unlock(&dqopt->dqio_mutex);
	mutex_unlock(&dquot->dq_lock);
	return ret;
}

/*
 *	Write dquot to disk
 */
int dquot_commit(struct dquot *dquot)
{
	int ret = 0, ret2 = 0;
	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

	mutex_lock(&dqopt->dqio_mutex);
	spin_lock(&dq_list_lock);
	if (!clear_dquot_dirty(dquot)) {
		spin_unlock(&dq_list_lock);
		goto out_sem;
	}
	spin_unlock(&dq_list_lock);
	/* Inactive dquot can be only if there was error during read/init
	 * => we have better not writing it */
	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
		ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
		if (info_dirty(&dqopt->info[dquot->dq_type]))
			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
		if (ret >= 0)
			ret = ret2;
	}
out_sem:
	mutex_unlock(&dqopt->dqio_mutex);
	return ret;
}

/*
 *	Release dquot
 */
int dquot_release(struct dquot *dquot)
{
	int ret = 0, ret2 = 0;
	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

	mutex_lock(&dquot->dq_lock);
	/* Check whether we are not racing with some other dqget() */
	if (atomic_read(&dquot->dq_count) > 1)
		goto out_dqlock;
	mutex_lock(&dqopt->dqio_mutex);
	if (dqopt->ops[dquot->dq_type]->release_dqblk) {
		ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
		/* Write the info */
		if (info_dirty(&dqopt->info[dquot->dq_type]))
			ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
		if (ret >= 0)
			ret = ret2;
	}
	clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
	mutex_unlock(&dqopt->dqio_mutex);
out_dqlock:
	mutex_unlock(&dquot->dq_lock);
	return ret;
}

/* Invalidate all dquots on the list. Note that this function is called after
 * quota is disabled and pointers from inodes removed so there cannot be new
 * quota users. There can still be some users of quotas due to inodes being
 * just deleted or pruned by prune_icache() (those are not attached to any
 * list). We have to wait for such users.
 */
static void invalidate_dquots(struct super_block *sb, int type)
{
	struct dquot *dquot, *tmp;

restart:
	spin_lock(&dq_list_lock);
	list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
		if (dquot->dq_sb != sb)
			continue;
		if (dquot->dq_type != type)
			continue;
		/* Wait for dquot users */
		if (atomic_read(&dquot->dq_count)) {
			DEFINE_WAIT(wait);

			atomic_inc(&dquot->dq_count);
			prepare_to_wait(&dquot->dq_wait_unused, &wait,
					TASK_UNINTERRUPTIBLE);
			spin_unlock(&dq_list_lock);
			/* Once dqput() wakes us up, we know it's time to free
			 * the dquot.
			 * IMPORTANT: we rely on the fact that there is always
			 * at most one process waiting for dquot to free.
			 * Otherwise dq_count would be > 1 and we would never
			 * wake up.
			 */
			if (atomic_read(&dquot->dq_count) > 1)
				schedule();
			finish_wait(&dquot->dq_wait_unused, &wait);
			dqput(dquot);
			/* At this moment dquot() need not exist (it could be
			 * reclaimed by prune_dqcache(). Hence we must
			 * restart. */
			goto restart;
		}
		/*
		 * Quota now has no users and it has been written on last
		 * dqput()
		 */
		remove_dquot_hash(dquot);
		remove_free_dquot(dquot);
		remove_inuse(dquot);
		kmem_cache_free(dquot_cachep, dquot);
	}
	spin_unlock(&dq_list_lock);
}

int vfs_quota_sync(struct super_block *sb, int type)
{
	struct list_head *dirty;
	struct dquot *dquot;
	struct quota_info *dqopt = sb_dqopt(sb);
	int cnt;

	mutex_lock(&dqopt->dqonoff_mutex);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (type != -1 && cnt != type)
			continue;
		if (!sb_has_quota_enabled(sb, cnt))
			continue;
		spin_lock(&dq_list_lock);
		dirty = &dqopt->info[cnt].dqi_dirty_list;
		while (!list_empty(dirty)) {
			dquot = list_entry(dirty->next, struct dquot, dq_dirty);
			/* Dirty and inactive can be only bad dquot... */
			if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
				clear_dquot_dirty(dquot);
				continue;
			}
			/* Now we have active dquot from which someone is
 			 * holding reference so we can safely just increase
			 * use count */
			atomic_inc(&dquot->dq_count);
			dqstats.lookups++;
			spin_unlock(&dq_list_lock);
			sb->dq_op->write_dquot(dquot);
			dqput(dquot);
			spin_lock(&dq_list_lock);
		}
		spin_unlock(&dq_list_lock);
	}

	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
			&& info_dirty(&dqopt->info[cnt]))
			sb->dq_op->write_info(sb, cnt);
	spin_lock(&dq_list_lock);
	dqstats.syncs++;
	spin_unlock(&dq_list_lock);
	mutex_unlock(&dqopt->dqonoff_mutex);

	return 0;
}

/* Free unused dquots from cache */
static void prune_dqcache(int count)
{
	struct list_head *head;
	struct dquot *dquot;

	head = free_dquots.prev;
	while (head != &free_dquots && count) {
		dquot = list_entry(head, struct dquot, dq_free);
		remove_dquot_hash(dquot);
		remove_free_dquot(dquot);
		remove_inuse(dquot);
		kmem_cache_free(dquot_cachep, dquot);
		count--;
		head = free_dquots.prev;
	}
}

/*
 * This is called from kswapd when we think we need some
 * more memory
 */

static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
{
	if (nr) {
		spin_lock(&dq_list_lock);
		prune_dqcache(nr);
		spin_unlock(&dq_list_lock);
	}
	return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
}

/*
 * Put reference to dquot
 * NOTE: If you change this function please check whether dqput_blocks() works right...
 * MUST be called with either dqptr_sem or dqonoff_mutex held
 */
static void dqput(struct dquot *dquot)
{
	if (!dquot)
		return;
#ifdef __DQUOT_PARANOIA
	if (!atomic_read(&dquot->dq_count)) {
		printk("VFS: dqput: trying to free free dquot\n");
		printk("VFS: device %s, dquot of %s %d\n",
			dquot->dq_sb->s_id,
			quotatypes[dquot->dq_type],
			dquot->dq_id);
		BUG();
	}
#endif
	
	spin_lock(&dq_list_lock);
	dqstats.drops++;
	spin_unlock(&dq_list_lock);
we_slept:
	spin_lock(&dq_list_lock);
	if (atomic_read(&dquot->dq_count) > 1) {
		/* We have more than one user... nothing to do */
		atomic_dec(&dquot->dq_count);
		/* Releasing dquot during quotaoff phase? */
		if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
		    atomic_read(&dquot->dq_count) == 1)
			wake_up(&dquot->dq_wait_unused);
		spin_unlock(&dq_list_lock);
		return;
	}
	/* Need to release dquot? */
	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
		spin_unlock(&dq_list_lock);
		/* Commit dquot before releasing */
		dquot->dq_sb->dq_op->write_dquot(dquot);
		goto we_slept;
	}
	/* Clear flag in case dquot was inactive (something bad happened) */
	clear_dquot_dirty(dquot);
	if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
		spin_unlock(&dq_list_lock);
		dquot->dq_sb->dq_op->release_dquot(dquot);
		goto we_slept;
	}
	atomic_dec(&dquot->dq_count);
#ifdef __DQUOT_PARANOIA
	/* sanity check */
	BUG_ON(!list_empty(&dquot->dq_free));
#endif
	put_dquot_last(dquot);
	spin_unlock(&dq_list_lock);
}

static struct dquot *get_empty_dquot(struct super_block *sb, int type)
{
	struct dquot *dquot;

	dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
	if(!dquot)
		return NODQUOT;

	mutex_init(&dquot->dq_lock);
	INIT_LIST_HEAD(&dquot->dq_free);
	INIT_LIST_HEAD(&dquot->dq_inuse);
	INIT_HLIST_NODE(&dquot->dq_hash);
	INIT_LIST_HEAD(&dquot->dq_dirty);
	init_waitqueue_head(&dquot->dq_wait_unused);
	dquot->dq_sb = sb;
	dquot->dq_type = type;
	atomic_set(&dquot->dq_count, 1);

	return dquot;
}

/*
 * Get reference to dquot
 * MUST be called with either dqptr_sem or dqonoff_mutex held
 */
static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
{
	unsigned int hashent = hashfn(sb, id, type);
	struct dquot *dquot, *empty = NODQUOT;

        if (!sb_has_quota_enabled(sb, type))
		return NODQUOT;
we_slept:
	spin_lock(&dq_list_lock);
	if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
		if (empty == NODQUOT) {
			spin_unlock(&dq_list_lock);
			if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
				schedule();	/* Try to wait for a moment... */
			goto we_slept;
		}
		dquot = empty;
		dquot->dq_id = id;
		/* all dquots go on the inuse_list */
		put_inuse(dquot);
		/* hash it first so it can be found */
		insert_dquot_hash(dquot);
		dqstats.lookups++;
		spin_unlock(&dq_list_lock);
	} else {
		if (!atomic_read(&dquot->dq_count))
			remove_free_dquot(dquot);
		atomic_inc(&dquot->dq_count);
		dqstats.cache_hits++;
		dqstats.lookups++;
		spin_unlock(&dq_list_lock);
		if (empty)
			kmem_cache_free(dquot_cachep, empty);
	}
	/* Wait for dq_lock - after this we know that either dquot_release() is already
	 * finished or it will be canceled due to dq_count > 1 test */
	wait_on_dquot(dquot);
	/* Read the dquot and instantiate it (everything done only if needed) */
	if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
		dqput(dquot);
		return NODQUOT;
	}
#ifdef __DQUOT_PARANOIA
	BUG_ON(!dquot->dq_sb);	/* Has somebody invalidated entry under us? */
#endif

	return dquot;
}

static int dqinit_needed(struct inode *inode, int type)
{
	int cnt;

	if (IS_NOQUOTA(inode))
		return 0;
	if (type != -1)
		return inode->i_dquot[type] == NODQUOT;
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if (inode->i_dquot[cnt] == NODQUOT)
			return 1;
	return 0;
}

/* This routine is guarded by dqonoff_mutex mutex */
static void add_dquot_ref(struct super_block *sb, int type)
{
	struct list_head *p;

restart:
	file_list_lock();
	list_for_each(p, &sb->s_files) {
		struct file *filp = list_entry(p, struct file, f_u.fu_list);
		struct inode *inode = filp->f_path.dentry->d_inode;
		if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
			struct dentry *dentry = dget(filp->f_path.dentry);
			file_list_unlock();
			sb->dq_op->initialize(inode, type);
			dput(dentry);
			/* As we may have blocked we had better restart... */
			goto restart;
		}
	}
	file_list_unlock();
}

/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
static inline int dqput_blocks(struct dquot *dquot)
{
	if (atomic_read(&dquot->dq_count) <= 1)
		return 1;
	return 0;
}

/* Remove references to dquots from inode - add dquot to list for freeing if needed */
/* We can't race with anybody because we hold dqptr_sem for writing... */
int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
{
	struct dquot *dquot = inode->i_dquot[type];

	inode->i_dquot[type] = NODQUOT;
	if (dquot != NODQUOT) {
		if (dqput_blocks(dquot)) {
#ifdef __DQUOT_PARANOIA
			if (atomic_read(&dquot->dq_count) != 1)
				printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
#endif
			spin_lock(&dq_list_lock);
			list_add(&dquot->dq_free, tofree_head);	/* As dquot must have currently users it can't be on the free list... */
			spin_unlock(&dq_list_lock);
			return 1;
		}
		else
			dqput(dquot);   /* We have guaranteed we won't block */
	}
	return 0;
}

/* Free list of dquots - called from inode.c */
/* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
static void put_dquot_list(struct list_head *tofree_head)
{
	struct list_head *act_head;
	struct dquot *dquot;

	act_head = tofree_head->next;
	/* So now we have dquots on the list... Just free them */
	while (act_head != tofree_head) {
		dquot = list_entry(act_head, struct dquot, dq_free);
		act_head = act_head->next;
		list_del_init(&dquot->dq_free);	/* Remove dquot from the list so we won't have problems... */
		dqput(dquot);
	}
}

static void remove_dquot_ref(struct super_block *sb, int type,
		struct list_head *tofree_head)
{
	struct inode *inode;

	spin_lock(&inode_lock);
	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
		if (!IS_NOQUOTA(inode))
			remove_inode_dquot_ref(inode, type, tofree_head);
	}
	spin_unlock(&inode_lock);
}

/* Gather all references from inodes and drop them */
static void drop_dquot_ref(struct super_block *sb, int type)
{
	LIST_HEAD(tofree_head);

	if (sb->dq_op) {
		down_write(&sb_dqopt(sb)->dqptr_sem);
		remove_dquot_ref(sb, type, &tofree_head);
		up_write(&sb_dqopt(sb)->dqptr_sem);
		put_dquot_list(&tofree_head);
	}
}

static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
{
	dquot->dq_dqb.dqb_curinodes += number;
}

static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
{
	dquot->dq_dqb.dqb_curspace += number;
}

static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
{
	if (dquot->dq_dqb.dqb_curinodes > number)
		dquot->dq_dqb.dqb_curinodes -= number;
	else
		dquot->dq_dqb.dqb_curinodes = 0;
	if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
		dquot->dq_dqb.dqb_itime = (time_t) 0;
	clear_bit(DQ_INODES_B, &dquot->dq_flags);
}

static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
{
	if (dquot->dq_dqb.dqb_curspace > number)
		dquot->dq_dqb.dqb_curspace -= number;
	else
		dquot->dq_dqb.dqb_curspace = 0;
	if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
		dquot->dq_dqb.dqb_btime = (time_t) 0;
	clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}

static int flag_print_warnings = 1;

static inline int need_print_warning(struct dquot *dquot)
{
	if (!flag_print_warnings)
		return 0;

	switch (dquot->dq_type) {
		case USRQUOTA:
			return current->fsuid == dquot->dq_id;
		case GRPQUOTA:
			return in_group_p(dquot->dq_id);
	}
	return 0;
}

/* Values of warnings */
#define NOWARN 0
#define IHARDWARN 1
#define ISOFTLONGWARN 2
#define ISOFTWARN 3
#define BHARDWARN 4
#define BSOFTLONGWARN 5
#define BSOFTWARN 6

/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const char warntype)
{
	char *msg = NULL;
	struct tty_struct *tty;
	int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
	  ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);

	if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
		return;

	mutex_lock(&tty_mutex);
	tty = get_current_tty();
	if (!tty)
		goto out_lock;
	tty_write_message(tty, dquot->dq_sb->s_id);
	if (warntype == ISOFTWARN || warntype == BSOFTWARN)
		tty_write_message(tty, ": warning, ");
	else
		tty_write_message(tty, ": write failed, ");
	tty_write_message(tty, quotatypes[dquot->dq_type]);
	switch (warntype) {
		case IHARDWARN:
			msg = " file limit reached.\r\n";
			break;
		case ISOFTLONGWARN:
			msg = " file quota exceeded too long.\r\n";
			break;
		case ISOFTWARN:
			msg = " file quota exceeded.\r\n";
			break;
		case BHARDWARN:
			msg = " block limit reached.\r\n";
			break;
		case BSOFTLONGWARN:
			msg = " block quota exceeded too long.\r\n";
			break;
		case BSOFTWARN:
			msg = " block quota exceeded.\r\n";
			break;
	}
	tty_write_message(tty, msg);
out_lock:
	mutex_unlock(&tty_mutex);
}

static inline void flush_warnings(struct dquot **dquots, char *warntype)
{
	int i;

	for (i = 0; i < MAXQUOTAS; i++)
		if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
			print_warning(dquots[i], warntype[i]);
}

static inline char ignore_hardlimit(struct dquot *dquot)
{
	struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];

	return capable(CAP_SYS_RESOURCE) &&
	    (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
}

/* needs dq_data_lock */
static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
	*warntype = NOWARN;
	if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
		return QUOTA_OK;

	if (dquot->dq_dqb.dqb_ihardlimit &&
	   (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
            !ignore_hardlimit(dquot)) {
		*warntype = IHARDWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_dqb.dqb_isoftlimit &&
	   (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
	    dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
            !ignore_hardlimit(dquot)) {
		*warntype = ISOFTLONGWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_dqb.dqb_isoftlimit &&
	   (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
	    dquot->dq_dqb.dqb_itime == 0) {
		*warntype = ISOFTWARN;
		dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
	}

	return QUOTA_OK;
}

/* needs dq_data_lock */
static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
{
	*warntype = 0;
	if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
		return QUOTA_OK;

	if (dquot->dq_dqb.dqb_bhardlimit &&
	   toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
            !ignore_hardlimit(dquot)) {
		if (!prealloc)
			*warntype = BHARDWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_dqb.dqb_bsoftlimit &&
	   toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
	    dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
            !ignore_hardlimit(dquot)) {
		if (!prealloc)
			*warntype = BSOFTLONGWARN;
		return NO_QUOTA;
	}

	if (dquot->dq_dqb.dqb_bsoftlimit &&
	   toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
	    dquot->dq_dqb.dqb_btime == 0) {
		if (!prealloc) {
			*warntype = BSOFTWARN;
			dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
		}
		else
			/*
			 * We don't allow preallocation to exceed softlimit so exceeding will
			 * be always printed
			 */
			return NO_QUOTA;
	}

	return QUOTA_OK;
}

/*
 *	Initialize quota pointers in inode
 *	Transaction must be started at entry
 */
int dquot_initialize(struct inode *inode, int type)
{
	unsigned int id = 0;
	int cnt, ret = 0;

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode))
		return 0;
	down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	/* Having dqptr_sem we know NOQUOTA flags can't be altered... */
	if (IS_NOQUOTA(inode))
		goto out_err;
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (type != -1 && cnt != type)
			continue;
		if (inode->i_dquot[cnt] == NODQUOT) {
			switch (cnt) {
				case USRQUOTA:
					id = inode->i_uid;
					break;
				case GRPQUOTA:
					id = inode->i_gid;
					break;
			}
			inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
		}
	}
out_err:
	up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return ret;
}

/*
 * 	Release all quotas referenced by inode
 *	Transaction must be started at an entry
 */
int dquot_drop(struct inode *inode)
{
	int cnt;

	down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] != NODQUOT) {
			dqput(inode->i_dquot[cnt]);
			inode->i_dquot[cnt] = NODQUOT;
		}
	}
	up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return 0;
}

/*
 * Following four functions update i_blocks+i_bytes fields and
 * quota information (together with appropriate checks)
 * NOTE: We absolutely rely on the fact that caller dirties
 * the inode (usually macros in quotaops.h care about this) and
 * holds a handle for the current transaction so that dquot write and
 * inode write go into the same transaction.
 */

/*
 * This operation can block, but only after everything is updated
 */
int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
{
	int cnt, ret = NO_QUOTA;
	char warntype[MAXQUOTAS];

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode)) {
out_add:
		inode_add_bytes(inode, number);
		return QUOTA_OK;
	}
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		warntype[cnt] = NOWARN;

	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	if (IS_NOQUOTA(inode)) {	/* Now we can do reliable test... */
		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
		goto out_add;
	}
	spin_lock(&dq_data_lock);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
			goto warn_put_all;
	}
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_incr_space(inode->i_dquot[cnt], number);
	}
	inode_add_bytes(inode, number);
	ret = QUOTA_OK;
warn_put_all:
	spin_unlock(&dq_data_lock);
	if (ret == QUOTA_OK)
		/* Dirtify all the dquots - this can block when journalling */
		for (cnt = 0; cnt < MAXQUOTAS; cnt++)
			if (inode->i_dquot[cnt])
				mark_dquot_dirty(inode->i_dquot[cnt]);
	flush_warnings(inode->i_dquot, warntype);
	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return ret;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_alloc_inode(const struct inode *inode, unsigned long number)
{
	int cnt, ret = NO_QUOTA;
	char warntype[MAXQUOTAS];

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode))
		return QUOTA_OK;
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		warntype[cnt] = NOWARN;
	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	if (IS_NOQUOTA(inode)) {
		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
		return QUOTA_OK;
	}
	spin_lock(&dq_data_lock);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
			goto warn_put_all;
	}

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_incr_inodes(inode->i_dquot[cnt], number);
	}
	ret = QUOTA_OK;
warn_put_all:
	spin_unlock(&dq_data_lock);
	if (ret == QUOTA_OK)
		/* Dirtify all the dquots - this can block when journalling */
		for (cnt = 0; cnt < MAXQUOTAS; cnt++)
			if (inode->i_dquot[cnt])
				mark_dquot_dirty(inode->i_dquot[cnt]);
	flush_warnings((struct dquot **)inode->i_dquot, warntype);
	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return ret;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_free_space(struct inode *inode, qsize_t number)
{
	unsigned int cnt;

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode)) {
out_sub:
		inode_sub_bytes(inode, number);
		return QUOTA_OK;
	}
	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	/* Now recheck reliably when holding dqptr_sem */
	if (IS_NOQUOTA(inode)) {
		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
		goto out_sub;
	}
	spin_lock(&dq_data_lock);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_decr_space(inode->i_dquot[cnt], number);
	}
	inode_sub_bytes(inode, number);
	spin_unlock(&dq_data_lock);
	/* Dirtify all the dquots - this can block when journalling */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if (inode->i_dquot[cnt])
			mark_dquot_dirty(inode->i_dquot[cnt]);
	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return QUOTA_OK;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_free_inode(const struct inode *inode, unsigned long number)
{
	unsigned int cnt;

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode))
		return QUOTA_OK;
	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	/* Now recheck reliably when holding dqptr_sem */
	if (IS_NOQUOTA(inode)) {
		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
		return QUOTA_OK;
	}
	spin_lock(&dq_data_lock);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_decr_inodes(inode->i_dquot[cnt], number);
	}
	spin_unlock(&dq_data_lock);
	/* Dirtify all the dquots - this can block when journalling */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if (inode->i_dquot[cnt])
			mark_dquot_dirty(inode->i_dquot[cnt]);
	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return QUOTA_OK;
}

/*
 * Transfer the number of inode and blocks from one diskquota to an other.
 *
 * This operation can block, but only after everything is updated
 * A transaction must be started when entering this function.
 */
int dquot_transfer(struct inode *inode, struct iattr *iattr)
{
	qsize_t space;
	struct dquot *transfer_from[MAXQUOTAS];
	struct dquot *transfer_to[MAXQUOTAS];
	int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
	    chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
	char warntype[MAXQUOTAS];

	/* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
	if (IS_NOQUOTA(inode))
		return QUOTA_OK;
	/* Clear the arrays */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
		warntype[cnt] = NOWARN;
	}
	down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	/* Now recheck reliably when holding dqptr_sem */
	if (IS_NOQUOTA(inode)) {	/* File without quota accounting? */
		up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
		return QUOTA_OK;
	}
	/* First build the transfer_to list - here we can block on
	 * reading/instantiating of dquots.  We know that the transaction for
	 * us was already started so we don't violate lock ranking here */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		switch (cnt) {
			case USRQUOTA:
				if (!chuid)
					continue;
				transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
				break;
			case GRPQUOTA:
				if (!chgid)
					continue;
				transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
				break;
		}
	}
	spin_lock(&dq_data_lock);
	space = inode_get_bytes(inode);
	/* Build the transfer_from list and check the limits */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (transfer_to[cnt] == NODQUOT)
			continue;
		transfer_from[cnt] = inode->i_dquot[cnt];
		if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
		    check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
			goto warn_put_all;
	}

	/*
	 * Finally perform the needed transfer from transfer_from to transfer_to
	 */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		/*
		 * Skip changes for same uid or gid or for turned off quota-type.
		 */
		if (transfer_to[cnt] == NODQUOT)
			continue;

		/* Due to IO error we might not have transfer_from[] structure */
		if (transfer_from[cnt]) {
			dquot_decr_inodes(transfer_from[cnt], 1);
			dquot_decr_space(transfer_from[cnt], space);
		}

		dquot_incr_inodes(transfer_to[cnt], 1);
		dquot_incr_space(transfer_to[cnt], space);

		inode->i_dquot[cnt] = transfer_to[cnt];
	}
	ret = QUOTA_OK;
warn_put_all:
	spin_unlock(&dq_data_lock);
	/* Dirtify all the dquots - this can block when journalling */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (transfer_from[cnt])
			mark_dquot_dirty(transfer_from[cnt]);
		if (transfer_to[cnt])
			mark_dquot_dirty(transfer_to[cnt]);
	}
	flush_warnings(transfer_to, warntype);
	
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
			dqput(transfer_from[cnt]);
		if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
			dqput(transfer_to[cnt]);
	}
	up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
	return ret;
}

/*
 * Write info of quota file to disk
 */
int dquot_commit_info(struct super_block *sb, int type)
{
	int ret;
	struct quota_info *dqopt = sb_dqopt(sb);

	mutex_lock(&dqopt->dqio_mutex);
	ret = dqopt->ops[type]->write_file_info(sb, type);
	mutex_unlock(&dqopt->dqio_mutex);
	return ret;
}

/*
 * Definitions of diskquota operations.
 */
struct dquot_operations dquot_operations = {
	.initialize	= dquot_initialize,
	.drop		= dquot_drop,
	.alloc_space	= dquot_alloc_space,
	.alloc_inode	= dquot_alloc_inode,
	.free_space	= dquot_free_space,
	.free_inode	= dquot_free_inode,
	.transfer	= dquot_transfer,
	.write_dquot	= dquot_commit,
	.acquire_dquot	= dquot_acquire,
	.release_dquot	= dquot_release,
	.mark_dirty	= dquot_mark_dquot_dirty,
	.write_info	= dquot_commit_info
};

static inline void set_enable_flags(struct quota_info *dqopt, int type)
{
	switch (type) {
		case USRQUOTA:
			dqopt->flags |= DQUOT_USR_ENABLED;
			break;
		case GRPQUOTA:
			dqopt->flags |= DQUOT_GRP_ENABLED;
			break;
	}
}

static inline void reset_enable_flags(struct quota_info *dqopt, int type)
{
	switch (type) {
		case USRQUOTA:
			dqopt->flags &= ~DQUOT_USR_ENABLED;
			break;
		case GRPQUOTA:
			dqopt->flags &= ~DQUOT_GRP_ENABLED;
			break;
	}
}

/*
 * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
 */
int vfs_quota_off(struct super_block *sb, int type)
{
	int cnt;
	struct quota_info *dqopt = sb_dqopt(sb);
	struct inode *toputinode[MAXQUOTAS];

	/* We need to serialize quota_off() for device */
	mutex_lock(&dqopt->dqonoff_mutex);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		toputinode[cnt] = NULL;
		if (type != -1 && cnt != type)
			continue;
		if (!sb_has_quota_enabled(sb, cnt))
			continue;
		reset_enable_flags(dqopt, cnt);

		/* Note: these are blocking operations */
		drop_dquot_ref(sb, cnt);
		invalidate_dquots(sb, cnt);
		/*
		 * Now all dquots should be invalidated, all writes done so we should be only
		 * users of the info. No locks needed.
		 */
		if (info_dirty(&dqopt->info[cnt]))
			sb->dq_op->write_info(sb, cnt);
		if (dqopt->ops[cnt]->free_file_info)
			dqopt->ops[cnt]->free_file_info(sb, cnt);
		put_quota_format(dqopt->info[cnt].dqi_format);

		toputinode[cnt] = dqopt->files[cnt];
		dqopt->files[cnt] = NULL;
		dqopt->info[cnt].dqi_flags = 0;
		dqopt->info[cnt].dqi_igrace = 0;
		dqopt->info[cnt].dqi_bgrace = 0;
		dqopt->ops[cnt] = NULL;
	}
	mutex_unlock(&dqopt->dqonoff_mutex);
	/* Sync the superblock so that buffers with quota data are written to
	 * disk (and so userspace sees correct data afterwards). */
	if (sb->s_op->sync_fs)
		sb->s_op->sync_fs(sb, 1);
	sync_blockdev(sb->s_bdev);
	/* Now the quota files are just ordinary files and we can set the
	 * inode flags back. Moreover we discard the pagecache so that
	 * userspace sees the writes we did bypassing the pagecache. We
	 * must also discard the blockdev buffers so that we see the
	 * changes done by userspace on the next quotaon() */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
		if (toputinode[cnt]) {
			mutex_lock(&dqopt->dqonoff_mutex);
			/* If quota was reenabled in the meantime, we have
			 * nothing to do */
			if (!sb_has_quota_enabled(sb, cnt)) {
				mutex_lock(&toputinode[cnt]->i_mutex);
				toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
				  S_NOATIME | S_NOQUOTA);
				truncate_inode_pages(&toputinode[cnt]->i_data, 0);
				mutex_unlock(&toputinode[cnt]->i_mutex);
				mark_inode_dirty(toputinode[cnt]);
				iput(toputinode[cnt]);
			}
			mutex_unlock(&dqopt->dqonoff_mutex);
		}
	if (sb->s_bdev)
		invalidate_bdev(sb->s_bdev, 0);
	return 0;
}

/*
 *	Turn quotas on on a device
 */

/* Helper function when we already have the inode */
static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
{
	struct quota_format_type *fmt = find_quota_format(format_id);
	struct super_block *sb = inode->i_sb;
	struct quota_info *dqopt = sb_dqopt(sb);
	int error;
	int oldflags = -1;

	if (!fmt)
		return -ESRCH;
	if (!S_ISREG(inode->i_mode)) {
		error = -EACCES;
		goto out_fmt;
	}
	if (IS_RDONLY(inode)) {
		error = -EROFS;
		goto out_fmt;
	}
	if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
		error = -EINVAL;
		goto out_fmt;
	}

	/* As we bypass the pagecache we must now flush the inode so that
	 * we see all the changes from userspace... */
	write_inode_now(inode, 1);
	/* And now flush the block cache so that kernel sees the changes */
	invalidate_bdev(sb->s_bdev, 0);
	mutex_lock(&inode->i_mutex);
	mutex_lock(&dqopt->dqonoff_mutex);
	if (sb_has_quota_enabled(sb, type)) {
		error = -EBUSY;
		goto out_lock;
	}
	/* We don't want quota and atime on quota files (deadlocks possible)
	 * Also nobody should write to the file - we use special IO operations
	 * which ignore the immutable bit. */
	down_write(&dqopt->dqptr_sem);
	oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
	inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
	up_write(&dqopt->dqptr_sem);
	sb->dq_op->drop(inode);

	error = -EIO;
	dqopt->files[type] = igrab(inode);
	if (!dqopt->files[type])
		goto out_lock;
	error = -EINVAL;
	if (!fmt->qf_ops->check_quota_file(sb, type))
		goto out_file_init;

	dqopt->ops[type] = fmt->qf_ops;
	dqopt->info[type].dqi_format = fmt;
	INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
	mutex_lock(&dqopt->dqio_mutex);
	if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
		mutex_unlock(&dqopt->dqio_mutex);
		goto out_file_init;
	}
	mutex_unlock(&dqopt->dqio_mutex);
	mutex_unlock(&inode->i_mutex);
	set_enable_flags(dqopt, type);

	add_dquot_ref(sb, type);
	mutex_unlock(&dqopt->dqonoff_mutex);

	return 0;

out_file_init:
	dqopt->files[type] = NULL;
	iput(inode);
out_lock:
	mutex_unlock(&dqopt->dqonoff_mutex);
	if (oldflags != -1) {
		down_write(&dqopt->dqptr_sem);
		/* Set the flags back (in the case of accidental quotaon()
		 * on a wrong file we don't want to mess up the flags) */
		inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
		inode->i_flags |= oldflags;
		up_write(&dqopt->dqptr_sem);
	}
	mutex_unlock(&inode->i_mutex);
out_fmt:
	put_quota_format(fmt);

	return error; 
}

/* Actual function called from quotactl() */
int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
{
	struct nameidata nd;
	int error;

	error = path_lookup(path, LOOKUP_FOLLOW, &nd);
	if (error < 0)
		return error;
	error = security_quota_on(nd.dentry);
	if (error)
		goto out_path;
	/* Quota file not on the same filesystem? */
	if (nd.mnt->mnt_sb != sb)
		error = -EXDEV;
	else
		error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
out_path:
	path_release(&nd);
	return error;
}

/*
 * This function is used when filesystem needs to initialize quotas
 * during mount time.
 */
int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
		int format_id, int type)
{
	struct dentry *dentry;
	int error;

	dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	if (!dentry->d_inode) {
		error = -ENOENT;
		goto out;
	}

	error = security_quota_on(dentry);
	if (!error)
		error = vfs_quota_on_inode(dentry->d_inode, type, format_id);

out:
	dput(dentry);
	return error;
}

/* Generic routine for getting common part of quota structure */
static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
	struct mem_dqblk *dm = &dquot->dq_dqb;

	spin_lock(&dq_data_lock);
	di->dqb_bhardlimit = dm->dqb_bhardlimit;
	di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
	di->dqb_curspace = dm->dqb_curspace;
	di->dqb_ihardlimit = dm->dqb_ihardlimit;
	di->dqb_isoftlimit = dm->dqb_isoftlimit;
	di->dqb_curinodes = dm->dqb_curinodes;
	di->dqb_btime = dm->dqb_btime;
	di->dqb_itime = dm->dqb_itime;
	di->dqb_valid = QIF_ALL;
	spin_unlock(&dq_data_lock);
}

int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
	struct dquot *dquot;

	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	if (!(dquot = dqget(sb, id, type))) {
		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
		return -ESRCH;
	}
	do_get_dqblk(dquot, di);
	dqput(dquot);
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
	return 0;
}

/* Generic routine for setting common part of quota structure */
static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
	struct mem_dqblk *dm = &dquot->dq_dqb;
	int check_blim = 0, check_ilim = 0;

	spin_lock(&dq_data_lock);
	if (di->dqb_valid & QIF_SPACE) {
		dm->dqb_curspace = di->dqb_curspace;
		check_blim = 1;
	}
	if (di->dqb_valid & QIF_BLIMITS) {
		dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
		dm->dqb_bhardlimit = di->dqb_bhardlimit;
		check_blim = 1;
	}
	if (di->dqb_valid & QIF_INODES) {
		dm->dqb_curinodes = di->dqb_curinodes;
		check_ilim = 1;
	}
	if (di->dqb_valid & QIF_ILIMITS) {
		dm->dqb_isoftlimit = di->dqb_isoftlimit;
		dm->dqb_ihardlimit = di->dqb_ihardlimit;
		check_ilim = 1;
	}
	if (di->dqb_valid & QIF_BTIME)
		dm->dqb_btime = di->dqb_btime;
	if (di->dqb_valid & QIF_ITIME)
		dm->dqb_itime = di->dqb_itime;

	if (check_blim) {
		if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
			dm->dqb_btime = 0;
			clear_bit(DQ_BLKS_B, &dquot->dq_flags);
		}
		else if (!(di->dqb_valid & QIF_BTIME))	/* Set grace only if user hasn't provided his own... */
			dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
	}
	if (check_ilim) {
		if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
			dm->dqb_itime = 0;
			clear_bit(DQ_INODES_B, &dquot->dq_flags);
		}
		else if (!(di->dqb_valid & QIF_ITIME))	/* Set grace only if user hasn't provided his own... */
			dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
	}
	if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
		clear_bit(DQ_FAKE_B, &dquot->dq_flags);
	else
		set_bit(DQ_FAKE_B, &dquot->dq_flags);
	spin_unlock(&dq_data_lock);
	mark_dquot_dirty(dquot);
}

int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
	struct dquot *dquot;

	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	if (!(dquot = dqget(sb, id, type))) {
		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
		return -ESRCH;
	}
	do_set_dqblk(dquot, di);
	dqput(dquot);
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
	return 0;
}

/* Generic routine for getting common part of quota file information */
int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
	struct mem_dqinfo *mi;
  
	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	if (!sb_has_quota_enabled(sb, type)) {
		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
		return -ESRCH;
	}
	mi = sb_dqopt(sb)->info + type;
	spin_lock(&dq_data_lock);
	ii->dqi_bgrace = mi->dqi_bgrace;
	ii->dqi_igrace = mi->dqi_igrace;
	ii->dqi_flags = mi->dqi_flags & DQF_MASK;
	ii->dqi_valid = IIF_ALL;
	spin_unlock(&dq_data_lock);
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
	return 0;
}

/* Generic routine for setting common part of quota file information */
int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
	struct mem_dqinfo *mi;

	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	if (!sb_has_quota_enabled(sb, type)) {
		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
		return -ESRCH;
	}
	mi = sb_dqopt(sb)->info + type;
	spin_lock(&dq_data_lock);
	if (ii->dqi_valid & IIF_BGRACE)
		mi->dqi_bgrace = ii->dqi_bgrace;
	if (ii->dqi_valid & IIF_IGRACE)
		mi->dqi_igrace = ii->dqi_igrace;
	if (ii->dqi_valid & IIF_FLAGS)
		mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
	spin_unlock(&dq_data_lock);
	mark_info_dirty(sb, type);
	/* Force write to disk */
	sb->dq_op->write_info(sb, type);
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
	return 0;
}

struct quotactl_ops vfs_quotactl_ops = {
	.quota_on	= vfs_quota_on,
	.quota_off	= vfs_quota_off,
	.quota_sync	= vfs_quota_sync,
	.get_info	= vfs_get_dqinfo,
	.set_info	= vfs_set_dqinfo,
	.get_dqblk	= vfs_get_dqblk,
	.set_dqblk	= vfs_set_dqblk
};

static ctl_table fs_dqstats_table[] = {
	{
		.ctl_name	= FS_DQ_LOOKUPS,
		.procname	= "lookups",
		.data		= &dqstats.lookups,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_DROPS,
		.procname	= "drops",
		.data		= &dqstats.drops,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_READS,
		.procname	= "reads",
		.data		= &dqstats.reads,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_WRITES,
		.procname	= "writes",
		.data		= &dqstats.writes,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_CACHE_HITS,
		.procname	= "cache_hits",
		.data		= &dqstats.cache_hits,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_ALLOCATED,
		.procname	= "allocated_dquots",
		.data		= &dqstats.allocated_dquots,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_FREE,
		.procname	= "free_dquots",
		.data		= &dqstats.free_dquots,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_SYNCS,
		.procname	= "syncs",
		.data		= &dqstats.syncs,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DQ_WARNINGS,
		.procname	= "warnings",
		.data		= &flag_print_warnings,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{ .ctl_name = 0 },
};

static ctl_table fs_table[] = {
	{
		.ctl_name	= FS_DQSTATS,
		.procname	= "quota",
		.mode		= 0555,
		.child		= fs_dqstats_table,
	},
	{ .ctl_name = 0 },
};

static ctl_table sys_table[] = {
	{
		.ctl_name	= CTL_FS,
		.procname	= "fs",
		.mode		= 0555,
		.child		= fs_table,
	},
	{ .ctl_name = 0 },
};

static int __init dquot_init(void)
{
	int i;
	unsigned long nr_hash, order;

	printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);

	register_sysctl_table(sys_table, 0);

	dquot_cachep = kmem_cache_create("dquot", 
			sizeof(struct dquot), sizeof(unsigned long) * 4,
			(SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
				SLAB_MEM_SPREAD|SLAB_PANIC),
			NULL, NULL);

	order = 0;
	dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
	if (!dquot_hash)
		panic("Cannot create dquot hash table");

	/* Find power-of-two hlist_heads which can fit into allocation */
	nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
	dq_hash_bits = 0;
	do {
		dq_hash_bits++;
	} while (nr_hash >> dq_hash_bits);
	dq_hash_bits--;

	nr_hash = 1UL << dq_hash_bits;
	dq_hash_mask = nr_hash - 1;
	for (i = 0; i < nr_hash; i++)
		INIT_HLIST_HEAD(dquot_hash + i);

	printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
			nr_hash, order, (PAGE_SIZE << order));

	set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);

	return 0;
}
module_init(dquot_init);

EXPORT_SYMBOL(register_quota_format);
EXPORT_SYMBOL(unregister_quota_format);
EXPORT_SYMBOL(dqstats);
EXPORT_SYMBOL(dq_data_lock);
EXPORT_SYMBOL(vfs_quota_on);
EXPORT_SYMBOL(vfs_quota_on_mount);
EXPORT_SYMBOL(vfs_quota_off);
EXPORT_SYMBOL(vfs_quota_sync);
EXPORT_SYMBOL(vfs_get_dqinfo);
EXPORT_SYMBOL(vfs_set_dqinfo);
EXPORT_SYMBOL(vfs_get_dqblk);
EXPORT_SYMBOL(vfs_set_dqblk);
EXPORT_SYMBOL(dquot_commit);
EXPORT_SYMBOL(dquot_commit_info);
EXPORT_SYMBOL(dquot_acquire);
EXPORT_SYMBOL(dquot_release);
EXPORT_SYMBOL(dquot_mark_dquot_dirty);
EXPORT_SYMBOL(dquot_initialize);
EXPORT_SYMBOL(dquot_drop);
EXPORT_SYMBOL(dquot_alloc_space);
EXPORT_SYMBOL(dquot_alloc_inode);
EXPORT_SYMBOL(dquot_free_space);
EXPORT_SYMBOL(dquot_free_inode);
EXPORT_SYMBOL(dquot_transfer);