aboutsummaryrefslogtreecommitdiffstats
path: root/fs/nfs/dir.c
blob: 3ddda6f7ecc2dfad9c9c2b000b9a406349a7f65d (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
/*
 *  linux/fs/nfs/dir.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  nfs directory handling functions
 *
 * 10 Apr 1996	Added silly rename for unlink	--okir
 * 28 Sep 1996	Improved directory cache --okir
 * 23 Aug 1997  Claus Heine claus@momo.math.rwth-aachen.de 
 *              Re-implemented silly rename for unlink, newly implemented
 *              silly rename for nfs_rename() following the suggestions
 *              of Olaf Kirch (okir) found in this file.
 *              Following Linus comments on my original hack, this version
 *              depends only on the dcache stuff and doesn't touch the inode
 *              layer (iput() and friends).
 *  6 Jun 1999	Cache readdir lookups in the page cache. -DaveM
 */

#include <linux/time.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/namei.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "iostat.h"

#define NFS_PARANOIA 1
/* #define NFS_DEBUG_VERBOSE 1 */

static int nfs_opendir(struct inode *, struct file *);
static int nfs_readdir(struct file *, void *, filldir_t);
static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *);
static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *);
static int nfs_mkdir(struct inode *, struct dentry *, int);
static int nfs_rmdir(struct inode *, struct dentry *);
static int nfs_unlink(struct inode *, struct dentry *);
static int nfs_symlink(struct inode *, struct dentry *, const char *);
static int nfs_link(struct dentry *, struct inode *, struct dentry *);
static int nfs_mknod(struct inode *, struct dentry *, int, dev_t);
static int nfs_rename(struct inode *, struct dentry *,
		      struct inode *, struct dentry *);
static int nfs_fsync_dir(struct file *, struct dentry *, int);
static loff_t nfs_llseek_dir(struct file *, loff_t, int);

const struct file_operations nfs_dir_operations = {
	.llseek		= nfs_llseek_dir,
	.read		= generic_read_dir,
	.readdir	= nfs_readdir,
	.open		= nfs_opendir,
	.release	= nfs_release,
	.fsync		= nfs_fsync_dir,
};

struct inode_operations nfs_dir_inode_operations = {
	.create		= nfs_create,
	.lookup		= nfs_lookup,
	.link		= nfs_link,
	.unlink		= nfs_unlink,
	.symlink	= nfs_symlink,
	.mkdir		= nfs_mkdir,
	.rmdir		= nfs_rmdir,
	.mknod		= nfs_mknod,
	.rename		= nfs_rename,
	.permission	= nfs_permission,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
};

#ifdef CONFIG_NFS_V3
struct inode_operations nfs3_dir_inode_operations = {
	.create		= nfs_create,
	.lookup		= nfs_lookup,
	.link		= nfs_link,
	.unlink		= nfs_unlink,
	.symlink	= nfs_symlink,
	.mkdir		= nfs_mkdir,
	.rmdir		= nfs_rmdir,
	.mknod		= nfs_mknod,
	.rename		= nfs_rename,
	.permission	= nfs_permission,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
	.listxattr	= nfs3_listxattr,
	.getxattr	= nfs3_getxattr,
	.setxattr	= nfs3_setxattr,
	.removexattr	= nfs3_removexattr,
};
#endif  /* CONFIG_NFS_V3 */

#ifdef CONFIG_NFS_V4

static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
struct inode_operations nfs4_dir_inode_operations = {
	.create		= nfs_create,
	.lookup		= nfs_atomic_lookup,
	.link		= nfs_link,
	.unlink		= nfs_unlink,
	.symlink	= nfs_symlink,
	.mkdir		= nfs_mkdir,
	.rmdir		= nfs_rmdir,
	.mknod		= nfs_mknod,
	.rename		= nfs_rename,
	.permission	= nfs_permission,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
	.getxattr       = nfs4_getxattr,
	.setxattr       = nfs4_setxattr,
	.listxattr      = nfs4_listxattr,
};

#endif /* CONFIG_NFS_V4 */

/*
 * Open file
 */
static int
nfs_opendir(struct inode *inode, struct file *filp)
{
	int res;

	dfprintk(VFS, "NFS: opendir(%s/%ld)\n",
			inode->i_sb->s_id, inode->i_ino);

	lock_kernel();
	/* Call generic open code in order to cache credentials */
	res = nfs_open(inode, filp);
	unlock_kernel();
	return res;
}

typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int);
typedef struct {
	struct file	*file;
	struct page	*page;
	unsigned long	page_index;
	u32		*ptr;
	u64		*dir_cookie;
	loff_t		current_index;
	struct nfs_entry *entry;
	decode_dirent_t	decode;
	int		plus;
	int		error;
} nfs_readdir_descriptor_t;

/* Now we cache directories properly, by stuffing the dirent
 * data directly in the page cache.
 *
 * Inode invalidation due to refresh etc. takes care of
 * _everything_, no sloppy entry flushing logic, no extraneous
 * copying, network direct to page cache, the way it was meant
 * to be.
 *
 * NOTE: Dirent information verification is done always by the
 *	 page-in of the RPC reply, nowhere else, this simplies
 *	 things substantially.
 */
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
{
	struct file	*file = desc->file;
	struct inode	*inode = file->f_dentry->d_inode;
	struct rpc_cred	*cred = nfs_file_cred(file);
	unsigned long	timestamp;
	int		error;

	dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n",
			__FUNCTION__, (long long)desc->entry->cookie,
			page->index);

 again:
	timestamp = jiffies;
	error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page,
					  NFS_SERVER(inode)->dtsize, desc->plus);
	if (error < 0) {
		/* We requested READDIRPLUS, but the server doesn't grok it */
		if (error == -ENOTSUPP && desc->plus) {
			NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
			desc->plus = 0;
			goto again;
		}
		goto error;
	}
	SetPageUptodate(page);
	spin_lock(&inode->i_lock);
	NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
	spin_unlock(&inode->i_lock);
	/* Ensure consistent page alignment of the data.
	 * Note: assumes we have exclusive access to this mapping either
	 *	 through inode->i_mutex or some other mechanism.
	 */
	if (page->index == 0)
		invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1);
	unlock_page(page);
	return 0;
 error:
	SetPageError(page);
	unlock_page(page);
	nfs_zap_caches(inode);
	desc->error = error;
	return -EIO;
}

static inline
int dir_decode(nfs_readdir_descriptor_t *desc)
{
	u32	*p = desc->ptr;
	p = desc->decode(p, desc->entry, desc->plus);
	if (IS_ERR(p))
		return PTR_ERR(p);
	desc->ptr = p;
	return 0;
}

static inline
void dir_page_release(nfs_readdir_descriptor_t *desc)
{
	kunmap(desc->page);
	page_cache_release(desc->page);
	desc->page = NULL;
	desc->ptr = NULL;
}

/*
 * Given a pointer to a buffer that has already been filled by a call
 * to readdir, find the next entry with cookie '*desc->dir_cookie'.
 *
 * If the end of the buffer has been reached, return -EAGAIN, if not,
 * return the offset within the buffer of the next entry to be
 * read.
 */
static inline
int find_dirent(nfs_readdir_descriptor_t *desc)
{
	struct nfs_entry *entry = desc->entry;
	int		loop_count = 0,
			status;

	while((status = dir_decode(desc)) == 0) {
		dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n",
				__FUNCTION__, (unsigned long long)entry->cookie);
		if (entry->prev_cookie == *desc->dir_cookie)
			break;
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}
	return status;
}

/*
 * Given a pointer to a buffer that has already been filled by a call
 * to readdir, find the entry at offset 'desc->file->f_pos'.
 *
 * If the end of the buffer has been reached, return -EAGAIN, if not,
 * return the offset within the buffer of the next entry to be
 * read.
 */
static inline
int find_dirent_index(nfs_readdir_descriptor_t *desc)
{
	struct nfs_entry *entry = desc->entry;
	int		loop_count = 0,
			status;

	for(;;) {
		status = dir_decode(desc);
		if (status)
			break;

		dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n",
				(unsigned long long)entry->cookie, desc->current_index);

		if (desc->file->f_pos == desc->current_index) {
			*desc->dir_cookie = entry->cookie;
			break;
		}
		desc->current_index++;
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}
	return status;
}

/*
 * Find the given page, and call find_dirent() or find_dirent_index in
 * order to try to return the next entry.
 */
static inline
int find_dirent_page(nfs_readdir_descriptor_t *desc)
{
	struct inode	*inode = desc->file->f_dentry->d_inode;
	struct page	*page;
	int		status;

	dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n",
			__FUNCTION__, desc->page_index,
			(long long) *desc->dir_cookie);

	page = read_cache_page(inode->i_mapping, desc->page_index,
			       (filler_t *)nfs_readdir_filler, desc);
	if (IS_ERR(page)) {
		status = PTR_ERR(page);
		goto out;
	}
	if (!PageUptodate(page))
		goto read_error;

	/* NOTE: Someone else may have changed the READDIRPLUS flag */
	desc->page = page;
	desc->ptr = kmap(page);		/* matching kunmap in nfs_do_filldir */
	if (*desc->dir_cookie != 0)
		status = find_dirent(desc);
	else
		status = find_dirent_index(desc);
	if (status < 0)
		dir_page_release(desc);
 out:
	dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status);
	return status;
 read_error:
	page_cache_release(page);
	return -EIO;
}

/*
 * Recurse through the page cache pages, and return a
 * filled nfs_entry structure of the next directory entry if possible.
 *
 * The target for the search is '*desc->dir_cookie' if non-0,
 * 'desc->file->f_pos' otherwise
 */
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
	int		loop_count = 0;
	int		res;

	/* Always search-by-index from the beginning of the cache */
	if (*desc->dir_cookie == 0) {
		dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n",
				(long long)desc->file->f_pos);
		desc->page_index = 0;
		desc->entry->cookie = desc->entry->prev_cookie = 0;
		desc->entry->eof = 0;
		desc->current_index = 0;
	} else
		dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n",
				(unsigned long long)*desc->dir_cookie);

	for (;;) {
		res = find_dirent_page(desc);
		if (res != -EAGAIN)
			break;
		/* Align to beginning of next page */
		desc->page_index ++;
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}

	dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, res);
	return res;
}

static inline unsigned int dt_type(struct inode *inode)
{
	return (inode->i_mode >> 12) & 15;
}

static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc);

/*
 * Once we've found the start of the dirent within a page: fill 'er up...
 */
static 
int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
		   filldir_t filldir)
{
	struct file	*file = desc->file;
	struct nfs_entry *entry = desc->entry;
	struct dentry	*dentry = NULL;
	unsigned long	fileid;
	int		loop_count = 0,
			res;

	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n",
			(unsigned long long)entry->cookie);

	for(;;) {
		unsigned d_type = DT_UNKNOWN;
		/* Note: entry->prev_cookie contains the cookie for
		 *	 retrieving the current dirent on the server */
		fileid = nfs_fileid_to_ino_t(entry->ino);

		/* Get a dentry if we have one */
		if (dentry != NULL)
			dput(dentry);
		dentry = nfs_readdir_lookup(desc);

		/* Use readdirplus info */
		if (dentry != NULL && dentry->d_inode != NULL) {
			d_type = dt_type(dentry->d_inode);
			fileid = dentry->d_inode->i_ino;
		}

		res = filldir(dirent, entry->name, entry->len, 
			      file->f_pos, fileid, d_type);
		if (res < 0)
			break;
		file->f_pos++;
		*desc->dir_cookie = entry->cookie;
		if (dir_decode(desc) != 0) {
			desc->page_index ++;
			break;
		}
		if (loop_count++ > 200) {
			loop_count = 0;
			schedule();
		}
	}
	dir_page_release(desc);
	if (dentry != NULL)
		dput(dentry);
	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
			(unsigned long long)*desc->dir_cookie, res);
	return res;
}

/*
 * If we cannot find a cookie in our cache, we suspect that this is
 * because it points to a deleted file, so we ask the server to return
 * whatever it thinks is the next entry. We then feed this to filldir.
 * If all goes well, we should then be able to find our way round the
 * cache on the next call to readdir_search_pagecache();
 *
 * NOTE: we cannot add the anonymous page to the pagecache because
 *	 the data it contains might not be page aligned. Besides,
 *	 we should already have a complete representation of the
 *	 directory in the page cache by the time we get here.
 */
static inline
int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
		     filldir_t filldir)
{
	struct file	*file = desc->file;
	struct inode	*inode = file->f_dentry->d_inode;
	struct rpc_cred	*cred = nfs_file_cred(file);
	struct page	*page = NULL;
	int		status;

	dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
			(unsigned long long)*desc->dir_cookie);

	page = alloc_page(GFP_HIGHUSER);
	if (!page) {
		status = -ENOMEM;
		goto out;
	}
	desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, *desc->dir_cookie,
						page,
						NFS_SERVER(inode)->dtsize,
						desc->plus);
	spin_lock(&inode->i_lock);
	NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
	spin_unlock(&inode->i_lock);
	desc->page = page;
	desc->ptr = kmap(page);		/* matching kunmap in nfs_do_filldir */
	if (desc->error >= 0) {
		if ((status = dir_decode(desc)) == 0)
			desc->entry->prev_cookie = *desc->dir_cookie;
	} else
		status = -EIO;
	if (status < 0)
		goto out_release;

	status = nfs_do_filldir(desc, dirent, filldir);

	/* Reset read descriptor so it searches the page cache from
	 * the start upon the next call to readdir_search_pagecache() */
	desc->page_index = 0;
	desc->entry->cookie = desc->entry->prev_cookie = 0;
	desc->entry->eof = 0;
 out:
	dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
			__FUNCTION__, status);
	return status;
 out_release:
	dir_page_release(desc);
	goto out;
}

/* The file offset position represents the dirent entry number.  A
   last cookie cache takes care of the common case of reading the
   whole directory.
 */
static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
	struct dentry	*dentry = filp->f_dentry;
	struct inode	*inode = dentry->d_inode;
	nfs_readdir_descriptor_t my_desc,
			*desc = &my_desc;
	struct nfs_entry my_entry;
	struct nfs_fh	 fh;
	struct nfs_fattr fattr;
	long		res;

	dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			(long long)filp->f_pos);
	nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);

	lock_kernel();

	res = nfs_revalidate_mapping(inode, filp->f_mapping);
	if (res < 0) {
		unlock_kernel();
		return res;
	}

	/*
	 * filp->f_pos points to the dirent entry number.
	 * *desc->dir_cookie has the cookie for the next entry. We have
	 * to either find the entry with the appropriate number or
	 * revalidate the cookie.
	 */
	memset(desc, 0, sizeof(*desc));

	desc->file = filp;
	desc->dir_cookie = &((struct nfs_open_context *)filp->private_data)->dir_cookie;
	desc->decode = NFS_PROTO(inode)->decode_dirent;
	desc->plus = NFS_USE_READDIRPLUS(inode);

	my_entry.cookie = my_entry.prev_cookie = 0;
	my_entry.eof = 0;
	my_entry.fh = &fh;
	my_entry.fattr = &fattr;
	nfs_fattr_init(&fattr);
	desc->entry = &my_entry;

	while(!desc->entry->eof) {
		res = readdir_search_pagecache(desc);

		if (res == -EBADCOOKIE) {
			/* This means either end of directory */
			if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) {
				/* Or that the server has 'lost' a cookie */
				res = uncached_readdir(desc, dirent, filldir);
				if (res >= 0)
					continue;
			}
			res = 0;
			break;
		}
		if (res == -ETOOSMALL && desc->plus) {
			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
			nfs_zap_caches(inode);
			desc->plus = 0;
			desc->entry->eof = 0;
			continue;
		}
		if (res < 0)
			break;

		res = nfs_do_filldir(desc, dirent, filldir);
		if (res < 0) {
			res = 0;
			break;
		}
	}
	unlock_kernel();
	if (res > 0)
		res = 0;
	dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			res);
	return res;
}

loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin)
{
	mutex_lock(&filp->f_dentry->d_inode->i_mutex);
	switch (origin) {
		case 1:
			offset += filp->f_pos;
		case 0:
			if (offset >= 0)
				break;
		default:
			offset = -EINVAL;
			goto out;
	}
	if (offset != filp->f_pos) {
		filp->f_pos = offset;
		((struct nfs_open_context *)filp->private_data)->dir_cookie = 0;
	}
out:
	mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
	return offset;
}

/*
 * All directory operations under NFS are synchronous, so fsync()
 * is a dummy operation.
 */
int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync)
{
	dfprintk(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n",
			dentry->d_parent->d_name.name, dentry->d_name.name,
			datasync);

	return 0;
}

/*
 * A check for whether or not the parent directory has changed.
 * In the case it has, we assume that the dentries are untrustworthy
 * and may need to be looked up again.
 */
static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
{
	if (IS_ROOT(dentry))
		return 1;
	if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0
			|| nfs_attribute_timeout(dir))
		return 0;
	return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
}

static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
{
	dentry->d_fsdata = (void *)verf;
}

/*
 * Whenever an NFS operation succeeds, we know that the dentry
 * is valid, so we update the revalidation timestamp.
 */
static inline void nfs_renew_times(struct dentry * dentry)
{
	dentry->d_time = jiffies;
}

/*
 * Return the intent data that applies to this particular path component
 *
 * Note that the current set of intents only apply to the very last
 * component of the path.
 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT.
 */
static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask)
{
	if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))
		return 0;
	return nd->flags & mask;
}

/*
 * Inode and filehandle revalidation for lookups.
 *
 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
 * or if the intent information indicates that we're about to open this
 * particular file and the "nocto" mount flag is not set.
 *
 */
static inline
int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
{
	struct nfs_server *server = NFS_SERVER(inode);

	if (nd != NULL) {
		/* VFS wants an on-the-wire revalidation */
		if (nd->flags & LOOKUP_REVAL)
			goto out_force;
		/* This is an open(2) */
		if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 &&
				!(server->flags & NFS_MOUNT_NOCTO))
			goto out_force;
	}
	return nfs_revalidate_inode(server, inode);
out_force:
	return __nfs_revalidate_inode(server, inode);
}

/*
 * We judge how long we want to trust negative
 * dentries by looking at the parent inode mtime.
 *
 * If parent mtime has changed, we revalidate, else we wait for a
 * period corresponding to the parent's attribute cache timeout value.
 */
static inline
int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
		       struct nameidata *nd)
{
	/* Don't revalidate a negative dentry if we're creating a new file */
	if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)
		return 0;
	return !nfs_check_verifier(dir, dentry);
}

/*
 * This is called every time the dcache has a lookup hit,
 * and we should check whether we can really trust that
 * lookup.
 *
 * NOTE! The hit can be a negative hit too, don't assume
 * we have an inode!
 *
 * If the parent directory is seen to have changed, we throw out the
 * cached dentry and do a new lookup.
 */
static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
{
	struct inode *dir;
	struct inode *inode;
	struct dentry *parent;
	int error;
	struct nfs_fh fhandle;
	struct nfs_fattr fattr;
	unsigned long verifier;

	parent = dget_parent(dentry);
	lock_kernel();
	dir = parent->d_inode;
	nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
	inode = dentry->d_inode;

	if (!inode) {
		if (nfs_neg_need_reval(dir, dentry, nd))
			goto out_bad;
		goto out_valid;
	}

	if (is_bad_inode(inode)) {
		dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n",
				__FUNCTION__, dentry->d_parent->d_name.name,
				dentry->d_name.name);
		goto out_bad;
	}

	/* Revalidate parent directory attribute cache */
	if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
		goto out_zap_parent;

	/* Force a full look up iff the parent directory has changed */
	if (nfs_check_verifier(dir, dentry)) {
		if (nfs_lookup_verify_inode(inode, nd))
			goto out_zap_parent;
		goto out_valid;
	}

	if (NFS_STALE(inode))
		goto out_bad;

	verifier = nfs_save_change_attribute(dir);
	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
	if (error)
		goto out_bad;
	if (nfs_compare_fh(NFS_FH(inode), &fhandle))
		goto out_bad;
	if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
		goto out_bad;

	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, verifier);
 out_valid:
	unlock_kernel();
	dput(parent);
	dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
			__FUNCTION__, dentry->d_parent->d_name.name,
			dentry->d_name.name);
	return 1;
out_zap_parent:
	nfs_zap_caches(dir);
 out_bad:
	NFS_CACHEINV(dir);
	if (inode && S_ISDIR(inode->i_mode)) {
		/* Purge readdir caches. */
		nfs_zap_caches(inode);
		/* If we have submounts, don't unhash ! */
		if (have_submounts(dentry))
			goto out_valid;
		shrink_dcache_parent(dentry);
	}
	d_drop(dentry);
	unlock_kernel();
	dput(parent);
	dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
			__FUNCTION__, dentry->d_parent->d_name.name,
			dentry->d_name.name);
	return 0;
}

/*
 * This is called from dput() when d_count is going to 0.
 */
static int nfs_dentry_delete(struct dentry *dentry)
{
	dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name,
		dentry->d_flags);

	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
		/* Unhash it, so that ->d_iput() would be called */
		return 1;
	}
	if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
		/* Unhash it, so that ancestors of killed async unlink
		 * files will be cleaned up during umount */
		return 1;
	}
	return 0;

}

/*
 * Called when the dentry loses inode.
 * We use it to clean up silly-renamed files.
 */
static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
{
	nfs_inode_return_delegation(inode);
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
		lock_kernel();
		inode->i_nlink--;
		nfs_complete_unlink(dentry);
		unlock_kernel();
	}
	/* When creating a negative dentry, we want to renew d_time */
	nfs_renew_times(dentry);
	iput(inode);
}

struct dentry_operations nfs_dentry_operations = {
	.d_revalidate	= nfs_lookup_revalidate,
	.d_delete	= nfs_dentry_delete,
	.d_iput		= nfs_dentry_iput,
};

/*
 * Use intent information to check whether or not we're going to do
 * an O_EXCL create using this path component.
 */
static inline
int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
{
	if (NFS_PROTO(dir)->version == 2)
		return 0;
	if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0)
		return 0;
	return (nd->intent.open.flags & O_EXCL) != 0;
}

static inline int nfs_reval_fsid(struct inode *dir,
		struct nfs_fh *fh, struct nfs_fattr *fattr)
{
	struct nfs_server *server = NFS_SERVER(dir);

	if (!nfs_fsid_equal(&server->fsid, &fattr->fsid))
		/* Revalidate fsid on root dir */
		return __nfs_revalidate_inode(server, dir->i_sb->s_root->d_inode);
	return 0;
}

static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
	struct dentry *res;
	struct inode *inode = NULL;
	int error;
	struct nfs_fh fhandle;
	struct nfs_fattr fattr;

	dfprintk(VFS, "NFS: lookup(%s/%s)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name);
	nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);

	res = ERR_PTR(-ENAMETOOLONG);
	if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
		goto out;

	res = ERR_PTR(-ENOMEM);
	dentry->d_op = NFS_PROTO(dir)->dentry_ops;

	lock_kernel();

	/* If we're doing an exclusive create, optimize away the lookup */
	if (nfs_is_exclusive_create(dir, nd))
		goto no_entry;

	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
	if (error == -ENOENT)
		goto no_entry;
	if (error < 0) {
		res = ERR_PTR(error);
		goto out_unlock;
	}
	error = nfs_reval_fsid(dir, &fhandle, &fattr);
	if (error < 0) {
		res = ERR_PTR(error);
		goto out_unlock;
	}
	inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
	res = (struct dentry *)inode;
	if (IS_ERR(res))
		goto out_unlock;
no_entry:
	res = d_add_unique(dentry, inode);
	if (res != NULL)
		dentry = res;
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unlock:
	unlock_kernel();
out:
	return res;
}

#ifdef CONFIG_NFS_V4
static int nfs_open_revalidate(struct dentry *, struct nameidata *);

struct dentry_operations nfs4_dentry_operations = {
	.d_revalidate	= nfs_open_revalidate,
	.d_delete	= nfs_dentry_delete,
	.d_iput		= nfs_dentry_iput,
};

/*
 * Use intent information to determine whether we need to substitute
 * the NFSv4-style stateful OPEN for the LOOKUP call
 */
static int is_atomic_open(struct inode *dir, struct nameidata *nd)
{
	if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0)
		return 0;
	/* NFS does not (yet) have a stateful open for directories */
	if (nd->flags & LOOKUP_DIRECTORY)
		return 0;
	/* Are we trying to write to a read only partition? */
	if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
		return 0;
	return 1;
}

static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
	struct dentry *res = NULL;
	int error;

	dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

	/* Check that we are indeed trying to open this file */
	if (!is_atomic_open(dir, nd))
		goto no_open;

	if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
		res = ERR_PTR(-ENAMETOOLONG);
		goto out;
	}
	dentry->d_op = NFS_PROTO(dir)->dentry_ops;

	/* Let vfs_create() deal with O_EXCL */
	if (nd->intent.open.flags & O_EXCL) {
		d_add(dentry, NULL);
		goto out;
	}

	/* Open the file on the server */
	lock_kernel();
	/* Revalidate parent directory attribute cache */
	error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
	if (error < 0) {
		res = ERR_PTR(error);
		unlock_kernel();
		goto out;
	}

	if (nd->intent.open.flags & O_CREAT) {
		nfs_begin_data_update(dir);
		res = nfs4_atomic_open(dir, dentry, nd);
		nfs_end_data_update(dir);
	} else
		res = nfs4_atomic_open(dir, dentry, nd);
	unlock_kernel();
	if (IS_ERR(res)) {
		error = PTR_ERR(res);
		switch (error) {
			/* Make a negative dentry */
			case -ENOENT:
				res = NULL;
				goto out;
			/* This turned out not to be a regular file */
			case -EISDIR:
			case -ENOTDIR:
				goto no_open;
			case -ELOOP:
				if (!(nd->intent.open.flags & O_NOFOLLOW))
					goto no_open;
			/* case -EINVAL: */
			default:
				goto out;
		}
	} else if (res != NULL)
		dentry = res;
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out:
	return res;
no_open:
	return nfs_lookup(dir, dentry, nd);
}

static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	struct dentry *parent = NULL;
	struct inode *inode = dentry->d_inode;
	struct inode *dir;
	unsigned long verifier;
	int openflags, ret = 0;

	parent = dget_parent(dentry);
	dir = parent->d_inode;
	if (!is_atomic_open(dir, nd))
		goto no_open;
	/* We can't create new files in nfs_open_revalidate(), so we
	 * optimize away revalidation of negative dentries.
	 */
	if (inode == NULL)
		goto out;
	/* NFS only supports OPEN on regular files */
	if (!S_ISREG(inode->i_mode))
		goto no_open;
	openflags = nd->intent.open.flags;
	/* We cannot do exclusive creation on a positive dentry */
	if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
		goto no_open;
	/* We can't create new files, or truncate existing ones here */
	openflags &= ~(O_CREAT|O_TRUNC);

	/*
	 * Note: we're not holding inode->i_mutex and so may be racing with
	 * operations that change the directory. We therefore save the
	 * change attribute *before* we do the RPC call.
	 */
	lock_kernel();
	verifier = nfs_save_change_attribute(dir);
	ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
	if (!ret)
		nfs_set_verifier(dentry, verifier);
	unlock_kernel();
out:
	dput(parent);
	if (!ret)
		d_drop(dentry);
	return ret;
no_open:
	dput(parent);
	if (inode != NULL && nfs_have_delegation(inode, FMODE_READ))
		return 1;
	return nfs_lookup_revalidate(dentry, nd);
}
#endif /* CONFIG_NFSV4 */

static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
{
	struct dentry *parent = desc->file->f_dentry;
	struct inode *dir = parent->d_inode;
	struct nfs_entry *entry = desc->entry;
	struct dentry *dentry, *alias;
	struct qstr name = {
		.name = entry->name,
		.len = entry->len,
	};
	struct inode *inode;

	switch (name.len) {
		case 2:
			if (name.name[0] == '.' && name.name[1] == '.')
				return dget_parent(parent);
			break;
		case 1:
			if (name.name[0] == '.')
				return dget(parent);
	}
	name.hash = full_name_hash(name.name, name.len);
	dentry = d_lookup(parent, &name);
	if (dentry != NULL)
		return dentry;
	if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
		return NULL;
	/* Note: caller is already holding the dir->i_mutex! */
	dentry = d_alloc(parent, &name);
	if (dentry == NULL)
		return NULL;
	dentry->d_op = NFS_PROTO(dir)->dentry_ops;
	inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
	if (IS_ERR(inode)) {
		dput(dentry);
		return NULL;
	}
	alias = d_add_unique(dentry, inode);
	if (alias != NULL) {
		dput(dentry);
		dentry = alias;
	}
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
	return dentry;
}

/*
 * Code common to create, mkdir, and mknod.
 */
int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
				struct nfs_fattr *fattr)
{
	struct inode *inode;
	int error = -EACCES;

	/* We may have been initialized further down */
	if (dentry->d_inode)
		return 0;
	if (fhandle->size == 0) {
		struct inode *dir = dentry->d_parent->d_inode;
		error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
		if (error)
			goto out_err;
	}
	if (!(fattr->valid & NFS_ATTR_FATTR)) {
		struct nfs_server *server = NFS_SB(dentry->d_sb);
		error = server->rpc_ops->getattr(server, fhandle, fattr);
		if (error < 0)
			goto out_err;
	}
	inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
	error = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out_err;
	d_instantiate(dentry, inode);
	return 0;
out_err:
	d_drop(dentry);
	return error;
}

/*
 * Following a failed create operation, we drop the dentry rather
 * than retain a negative dentry. This avoids a problem in the event
 * that the operation succeeded on the server, but an error in the
 * reply path made it appear to have failed.
 */
static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
		struct nameidata *nd)
{
	struct iattr attr;
	int error;
	int open_flags = 0;

	dfprintk(VFS, "NFS: create(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

	attr.ia_mode = mode;
	attr.ia_valid = ATTR_MODE;

	if (nd && (nd->flags & LOOKUP_CREATE))
		open_flags = nd->intent.open.flags;

	lock_kernel();
	nfs_begin_data_update(dir);
	error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
	nfs_end_data_update(dir);
	if (error != 0)
		goto out_err;
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
	unlock_kernel();
	return 0;
out_err:
	unlock_kernel();
	d_drop(dentry);
	return error;
}

/*
 * See comments for nfs_proc_create regarding failed operations.
 */
static int
nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
	struct iattr attr;
	int status;

	dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

	if (!new_valid_dev(rdev))
		return -EINVAL;

	attr.ia_mode = mode;
	attr.ia_valid = ATTR_MODE;

	lock_kernel();
	nfs_begin_data_update(dir);
	status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
	nfs_end_data_update(dir);
	if (status != 0)
		goto out_err;
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
	unlock_kernel();
	return 0;
out_err:
	unlock_kernel();
	d_drop(dentry);
	return status;
}

/*
 * See comments for nfs_proc_create regarding failed operations.
 */
static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	struct iattr attr;
	int error;

	dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

	attr.ia_valid = ATTR_MODE;
	attr.ia_mode = mode | S_IFDIR;

	lock_kernel();
	nfs_begin_data_update(dir);
	error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
	nfs_end_data_update(dir);
	if (error != 0)
		goto out_err;
	nfs_renew_times(dentry);
	nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
	unlock_kernel();
	return 0;
out_err:
	d_drop(dentry);
	unlock_kernel();
	return error;
}

static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	int error;

	dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n",
			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);

	lock_kernel();
	nfs_begin_data_update(dir);
	error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
	/* Ensure the VFS deletes this inode */
	if (error == 0 && dentry->d_inode != NULL)
		dentry->d_inode->i_nlink = 0;
	nfs_end_data_update(dir);
	unlock_kernel();

	return error;
}

static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
{
	static unsigned int sillycounter;
	const int      i_inosize  = sizeof(dir->i_ino)*2;
	const int      countersize = sizeof(sillycounter)*2;
	const int      slen       = sizeof(".nfs") + i_inosize + countersize - 1;
	char           silly[slen+1];
	struct qstr    qsilly;
	struct dentry *sdentry;
	int            error = -EIO;

	dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name, 
		atomic_read(&dentry->d_count));
	nfs_inc_stats(dir, NFSIOS_SILLYRENAME);

#ifdef NFS_PARANOIA
if (!dentry->d_inode)
printk("NFS: silly-renaming %s/%s, negative dentry??\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
#endif
	/*
	 * We don't allow a dentry to be silly-renamed twice.
	 */
	error = -EBUSY;
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
		goto out;

	sprintf(silly, ".nfs%*.*lx",
		i_inosize, i_inosize, dentry->d_inode->i_ino);

	/* Return delegation in anticipation of the rename */
	nfs_inode_return_delegation(dentry->d_inode);

	sdentry = NULL;
	do {
		char *suffix = silly + slen - countersize;

		dput(sdentry);
		sillycounter++;
		sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);

		dfprintk(VFS, "NFS: trying to rename %s to %s\n",
				dentry->d_name.name, silly);
		
		sdentry = lookup_one_len(silly, dentry->d_parent, slen);
		/*
		 * N.B. Better to return EBUSY here ... it could be
		 * dangerous to delete the file while it's in use.
		 */
		if (IS_ERR(sdentry))
			goto out;
	} while(sdentry->d_inode != NULL); /* need negative lookup */

	qsilly.name = silly;
	qsilly.len  = strlen(silly);
	nfs_begin_data_update(dir);
	if (dentry->d_inode) {
		nfs_begin_data_update(dentry->d_inode);
		error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
				dir, &qsilly);
		nfs_mark_for_revalidate(dentry->d_inode);
		nfs_end_data_update(dentry->d_inode);
	} else
		error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
				dir, &qsilly);
	nfs_end_data_update(dir);
	if (!error) {
		nfs_renew_times(dentry);
		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
		d_move(dentry, sdentry);
		error = nfs_async_unlink(dentry);
 		/* If we return 0 we don't unlink */
	}
	dput(sdentry);
out:
	return error;
}

/*
 * Remove a file after making sure there are no pending writes,
 * and after checking that the file has only one user. 
 *
 * We invalidate the attribute cache and free the inode prior to the operation
 * to avoid possible races if the server reuses the inode.
 */
static int nfs_safe_remove(struct dentry *dentry)
{
	struct inode *dir = dentry->d_parent->d_inode;
	struct inode *inode = dentry->d_inode;
	int error = -EBUSY;
		
	dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name);

	/* If the dentry was sillyrenamed, we simply call d_delete() */
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
		error = 0;
		goto out;
	}

	nfs_begin_data_update(dir);
	if (inode != NULL) {
		nfs_inode_return_delegation(inode);
		nfs_begin_data_update(inode);
		error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
		/* The VFS may want to delete this inode */
		if (error == 0)
			inode->i_nlink--;
		nfs_mark_for_revalidate(inode);
		nfs_end_data_update(inode);
	} else
		error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
	nfs_end_data_update(dir);
out:
	return error;
}

/*  We do silly rename. In case sillyrename() returns -EBUSY, the inode
 *  belongs to an active ".nfs..." file and we return -EBUSY.
 *
 *  If sillyrename() returns 0, we do nothing, otherwise we unlink.
 */
static int nfs_unlink(struct inode *dir, struct dentry *dentry)
{
	int error;
	int need_rehash = 0;

	dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
		dir->i_ino, dentry->d_name.name);

	lock_kernel();
	spin_lock(&dcache_lock);
	spin_lock(&dentry->d_lock);
	if (atomic_read(&dentry->d_count) > 1) {
		spin_unlock(&dentry->d_lock);
		spin_unlock(&dcache_lock);
		error = nfs_sillyrename(dir, dentry);
		unlock_kernel();
		return error;
	}
	if (!d_unhashed(dentry)) {
		__d_drop(dentry);
		need_rehash = 1;
	}
	spin_unlock(&dentry->d_lock);
	spin_unlock(&dcache_lock);
	error = nfs_safe_remove(dentry);
	if (!error) {
		nfs_renew_times(dentry);
		nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
	} else if (need_rehash)
		d_rehash(dentry);
	unlock_kernel();
	return error;
}

static int
nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
	struct iattr attr;
	struct nfs_fattr sym_attr;
	struct nfs_fh sym_fh;
	struct qstr qsymname;
	int error;

	dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
		dir->i_ino, dentry->d_name.name, symname);

#ifdef NFS_PARANOIA
if (dentry->d_inode)
printk("nfs_proc_symlink: %s/%s not negative!\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
#endif
	/*
	 * Fill in the sattr for the call.
 	 * Note: SunOS 4.1.2 crashes if the mode isn't initialized!
	 */
	attr.ia_valid = ATTR_MODE;
	attr.ia_mode = S_IFLNK | S_IRWXUGO;

	qsymname.name = symname;
	qsymname.len  = strlen(symname);

	lock_kernel();
	nfs_begin_data_update(dir);
	error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
					  &attr, &sym_fh, &sym_attr);
	nfs_end_data_update(dir);
	if (!error) {
		error = nfs_instantiate(dentry, &sym_fh, &sym_attr);
	} else {
		if (error == -EEXIST)
			printk("nfs_proc_symlink: %s/%s already exists??\n",
			       dentry->d_parent->d_name.name, dentry->d_name.name);
		d_drop(dentry);
	}
	unlock_kernel();
	return error;
}

static int 
nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
	struct inode *inode = old_dentry->d_inode;
	int error;

	dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
		old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
		dentry->d_parent->d_name.name, dentry->d_name.name);

	lock_kernel();
	nfs_begin_data_update(dir);
	nfs_begin_data_update(inode);
	error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
	if (error == 0) {
		atomic_inc(&inode->i_count);
		d_instantiate(dentry, inode);
	}
	nfs_end_data_update(inode);
	nfs_end_data_update(dir);
	unlock_kernel();
	return error;
}

/*
 * RENAME
 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
 * different file handle for the same inode after a rename (e.g. when
 * moving to a different directory). A fail-safe method to do so would
 * be to look up old_dir/old_name, create a link to new_dir/new_name and
 * rename the old file using the sillyrename stuff. This way, the original
 * file in old_dir will go away when the last process iput()s the inode.
 *
 * FIXED.
 * 
 * It actually works quite well. One needs to have the possibility for
 * at least one ".nfs..." file in each directory the file ever gets
 * moved or linked to which happens automagically with the new
 * implementation that only depends on the dcache stuff instead of
 * using the inode layer
 *
 * Unfortunately, things are a little more complicated than indicated
 * above. For a cross-directory move, we want to make sure we can get
 * rid of the old inode after the operation.  This means there must be
 * no pending writes (if it's a file), and the use count must be 1.
 * If these conditions are met, we can drop the dentries before doing
 * the rename.
 */
static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		      struct inode *new_dir, struct dentry *new_dentry)
{
	struct inode *old_inode = old_dentry->d_inode;
	struct inode *new_inode = new_dentry->d_inode;
	struct dentry *dentry = NULL, *rehash = NULL;
	int error = -EBUSY;

	/*
	 * To prevent any new references to the target during the rename,
	 * we unhash the dentry and free the inode in advance.
	 */
	lock_kernel();
	if (!d_unhashed(new_dentry)) {
		d_drop(new_dentry);
		rehash = new_dentry;
	}

	dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
		 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
		 new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
		 atomic_read(&new_dentry->d_count));

	/*
	 * First check whether the target is busy ... we can't
	 * safely do _any_ rename if the target is in use.
	 *
	 * For files, make a copy of the dentry and then do a 
	 * silly-rename. If the silly-rename succeeds, the
	 * copied dentry is hashed and becomes the new target.
	 */
	if (!new_inode)
		goto go_ahead;
	if (S_ISDIR(new_inode->i_mode)) {
		error = -EISDIR;
		if (!S_ISDIR(old_inode->i_mode))
			goto out;
	} else if (atomic_read(&new_dentry->d_count) > 2) {
		int err;
		/* copy the target dentry's name */
		dentry = d_alloc(new_dentry->d_parent,
				 &new_dentry->d_name);
		if (!dentry)
			goto out;

		/* silly-rename the existing target ... */
		err = nfs_sillyrename(new_dir, new_dentry);
		if (!err) {
			new_dentry = rehash = dentry;
			new_inode = NULL;
			/* instantiate the replacement target */
			d_instantiate(new_dentry, NULL);
		} else if (atomic_read(&new_dentry->d_count) > 1) {
		/* dentry still busy? */
#ifdef NFS_PARANOIA
			printk("nfs_rename: target %s/%s busy, d_count=%d\n",
			       new_dentry->d_parent->d_name.name,
			       new_dentry->d_name.name,
			       atomic_read(&new_dentry->d_count));
#endif
			goto out;
		}
	} else
		new_inode->i_nlink--;

go_ahead:
	/*
	 * ... prune child dentries and writebacks if needed.
	 */
	if (atomic_read(&old_dentry->d_count) > 1) {
		nfs_wb_all(old_inode);
		shrink_dcache_parent(old_dentry);
	}
	nfs_inode_return_delegation(old_inode);

	if (new_inode != NULL) {
		nfs_inode_return_delegation(new_inode);
		d_delete(new_dentry);
	}

	nfs_begin_data_update(old_dir);
	nfs_begin_data_update(new_dir);
	nfs_begin_data_update(old_inode);
	error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
					   new_dir, &new_dentry->d_name);
	nfs_mark_for_revalidate(old_inode);
	nfs_end_data_update(old_inode);
	nfs_end_data_update(new_dir);
	nfs_end_data_update(old_dir);
out:
	if (rehash)
		d_rehash(rehash);
	if (!error) {
		if (!S_ISDIR(old_inode->i_mode))
			d_move(old_dentry, new_dentry);
		nfs_renew_times(new_dentry);
		nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
	}

	/* new dentry created? */
	if (dentry)
		dput(dentry);
	unlock_kernel();
	return error;
}

int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_access_entry *cache = &nfsi->cache_access;

	if (cache->cred != cred
			|| time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
			|| (nfsi->cache_validity & NFS_INO_INVALID_ACCESS))
		return -ENOENT;
	memcpy(res, cache, sizeof(*res));
	return 0;
}

void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_access_entry *cache = &nfsi->cache_access;

	if (cache->cred != set->cred) {
		if (cache->cred)
			put_rpccred(cache->cred);
		cache->cred = get_rpccred(set->cred);
	}
	/* FIXME: replace current access_cache BKL reliance with inode->i_lock */
	spin_lock(&inode->i_lock);
	nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
	spin_unlock(&inode->i_lock);
	cache->jiffies = set->jiffies;
	cache->mask = set->mask;
}

static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
{
	struct nfs_access_entry cache;
	int status;

	status = nfs_access_get_cached(inode, cred, &cache);
	if (status == 0)
		goto out;

	/* Be clever: ask server to check for all possible rights */
	cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
	cache.cred = cred;
	cache.jiffies = jiffies;
	status = NFS_PROTO(inode)->access(inode, &cache);
	if (status != 0)
		return status;
	nfs_access_add_cache(inode, &cache);
out:
	if ((cache.mask & mask) == mask)
		return 0;
	return -EACCES;
}

int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	struct rpc_cred *cred;
	int res = 0;

	nfs_inc_stats(inode, NFSIOS_VFSACCESS);

	if (mask == 0)
		goto out;
	/* Is this sys_access() ? */
	if (nd != NULL && (nd->flags & LOOKUP_ACCESS))
		goto force_lookup;

	switch (inode->i_mode & S_IFMT) {
		case S_IFLNK:
			goto out;
		case S_IFREG:
			/* NFSv4 has atomic_open... */
			if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
					&& nd != NULL
					&& (nd->flags & LOOKUP_OPEN))
				goto out;
			break;
		case S_IFDIR:
			/*
			 * Optimize away all write operations, since the server
			 * will check permissions when we perform the op.
			 */
			if ((mask & MAY_WRITE) && !(mask & MAY_READ))
				goto out;
	}

force_lookup:
	lock_kernel();

	if (!NFS_PROTO(inode)->access)
		goto out_notsup;

	cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
	if (!IS_ERR(cred)) {
		res = nfs_do_access(inode, cred, mask);
		put_rpccred(cred);
	} else
		res = PTR_ERR(cred);
	unlock_kernel();
out:
	dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n",
		inode->i_sb->s_id, inode->i_ino, mask, res);
	return res;
out_notsup:
	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (res == 0)
		res = generic_permission(inode, mask, NULL);
	unlock_kernel();
	goto out;
}

/*
 * Local variables:
 *  version-control: t
 *  kept-new-versions: 5
 * End:
 */

Privacy Policy