summaryrefslogtreecommitdiffstats
path: root/fs/nfsd/export.c
blob: 46b48dbbdd3255260c2b505b49d87b8d2e874100 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * NFS exporting and validation.
 *
 * We maintain a list of clients, each of which has a list of
 * exports. To export an fs to a given client, you first have
 * to create the client entry with NFSCTL_ADDCLIENT, which
 * creates a client control block and adds it to the hash
 * table. Then, you call NFSCTL_EXPORT for each fs.
 *
 *
 * Copyright (C) 1995, 1996 Olaf Kirch, <okir@monad.swb.de>
 */

#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/module.h>
#include <linux/exportfs.h>
#include <linux/sunrpc/svc_xprt.h>

#include "nfsd.h"
#include "nfsfh.h"
#include "netns.h"
#include "pnfs.h"

#define NFSDDBG_FACILITY	NFSDDBG_EXPORT

/*
 * We have two caches.
 * One maps client+vfsmnt+dentry to export options - the export map
 * The other maps client+filehandle-fragment to export options. - the expkey map
 *
 * The export options are actually stored in the first map, and the
 * second map contains a reference to the entry in the first map.
 */

#define	EXPKEY_HASHBITS		8
#define	EXPKEY_HASHMAX		(1 << EXPKEY_HASHBITS)
#define	EXPKEY_HASHMASK		(EXPKEY_HASHMAX -1)

static void expkey_put(struct kref *ref)
{
	struct svc_expkey *key = container_of(ref, struct svc_expkey, h.ref);

	if (test_bit(CACHE_VALID, &key->h.flags) &&
	    !test_bit(CACHE_NEGATIVE, &key->h.flags))
		path_put(&key->ek_path);
	auth_domain_put(key->ek_client);
	kfree(key);
}

static void expkey_request(struct cache_detail *cd,
			   struct cache_head *h,
			   char **bpp, int *blen)
{
	/* client fsidtype \xfsid */
	struct svc_expkey *ek = container_of(h, struct svc_expkey, h);
	char type[5];

	qword_add(bpp, blen, ek->ek_client->name);
	snprintf(type, 5, "%d", ek->ek_fsidtype);
	qword_add(bpp, blen, type);
	qword_addhex(bpp, blen, (char*)ek->ek_fsid, key_len(ek->ek_fsidtype));
	(*bpp)[-1] = '\n';
}

static struct svc_expkey *svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new,
					    struct svc_expkey *old);
static struct svc_expkey *svc_expkey_lookup(struct cache_detail *cd, struct svc_expkey *);

static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
{
	/* client fsidtype fsid expiry [path] */
	char *buf;
	int len;
	struct auth_domain *dom = NULL;
	int err;
	int fsidtype;
	char *ep;
	struct svc_expkey key;
	struct svc_expkey *ek = NULL;

	if (mesg[mlen - 1] != '\n')
		return -EINVAL;
	mesg[mlen-1] = 0;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	err = -ENOMEM;
	if (!buf)
		goto out;

	err = -EINVAL;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;

	err = -ENOENT;
	dom = auth_domain_find(buf);
	if (!dom)
		goto out;
	dprintk("found domain %s\n", buf);

	err = -EINVAL;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
	fsidtype = simple_strtoul(buf, &ep, 10);
	if (*ep)
		goto out;
	dprintk("found fsidtype %d\n", fsidtype);
	if (key_len(fsidtype)==0) /* invalid type */
		goto out;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
	dprintk("found fsid length %d\n", len);
	if (len != key_len(fsidtype))
		goto out;

	/* OK, we seem to have a valid key */
	key.h.flags = 0;
	key.h.expiry_time = get_expiry(&mesg);
	if (key.h.expiry_time == 0)
		goto out;

	key.ek_client = dom;	
	key.ek_fsidtype = fsidtype;
	memcpy(key.ek_fsid, buf, len);

	ek = svc_expkey_lookup(cd, &key);
	err = -ENOMEM;
	if (!ek)
		goto out;

	/* now we want a pathname, or empty meaning NEGATIVE  */
	err = -EINVAL;
	len = qword_get(&mesg, buf, PAGE_SIZE);
	if (len < 0)
		goto out;
	dprintk("Path seems to be <%s>\n", buf);
	err = 0;
	if (len == 0) {
		set_bit(CACHE_NEGATIVE, &key.h.flags);
		ek = svc_expkey_update(cd, &key, ek);
		if (!ek)
			err = -ENOMEM;
	} else {
		err = kern_path(buf, 0, &key.ek_path);
		if (err)
			goto out;

		dprintk("Found the path %s\n", buf);

		ek = svc_expkey_update(cd, &key, ek);
		if (!ek)
			err = -ENOMEM;
		path_put(&key.ek_path);
	}
	cache_flush();
 out:
	if (ek)
		cache_put(&ek->h, cd);
	if (dom)
		auth_domain_put(dom);
	kfree(buf);
	return err;
}

static int expkey_show(struct seq_file *m,
		       struct cache_detail *cd,
		       struct cache_head *h)
{
	struct svc_expkey *ek ;
	int i;

	if (h ==NULL) {
		seq_puts(m, "#domain fsidtype fsid [path]\n");
		return 0;
	}
	ek = container_of(h, struct svc_expkey, h);
	seq_printf(m, "%s %d 0x", ek->ek_client->name,
		   ek->ek_fsidtype);
	for (i=0; i < key_len(ek->ek_fsidtype)/4; i++)
		seq_printf(m, "%08x", ek->ek_fsid[i]);
	if (test_bit(CACHE_VALID, &h->flags) && 
	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
		seq_printf(m, " ");
		seq_path(m, &ek->ek_path, "\\ \t\n");
	}
	seq_printf(m, "\n");
	return 0;
}

static inline int expkey_match (struct cache_head *a, struct cache_head *b)
{
	struct svc_expkey *orig = container_of(a, struct svc_expkey, h);
	struct svc_expkey *new = container_of(b, struct svc_expkey, h);

	if (orig->ek_fsidtype != new->ek_fsidtype ||
	    orig->ek_client != new->ek_client ||
	    memcmp(orig->ek_fsid, new->ek_fsid, key_len(orig->ek_fsidtype)) != 0)
		return 0;
	return 1;
}

static inline void expkey_init(struct cache_head *cnew,
				   struct cache_head *citem)
{
	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);

	kref_get(&item->ek_client->ref);
	new->ek_client = item->ek_client;
	new->ek_fsidtype = item->ek_fsidtype;

	memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid));
}

static inline void expkey_update(struct cache_head *cnew,
				   struct cache_head *citem)
{
	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);

	new->ek_path = item->ek_path;
	path_get(&item->ek_path);
}

static struct cache_head *expkey_alloc(void)
{
	struct svc_expkey *i = kmalloc(sizeof(*i), GFP_KERNEL);
	if (i)
		return &i->h;
	else
		return NULL;
}

static struct cache_detail svc_expkey_cache_template = {
	.owner		= THIS_MODULE,
	.hash_size	= EXPKEY_HASHMAX,
	.name		= "nfsd.fh",
	.cache_put	= expkey_put,
	.cache_request	= expkey_request,
	.cache_parse	= expkey_parse,
	.cache_show	= expkey_show,
	.match		= expkey_match,
	.init		= expkey_init,
	.update       	= expkey_update,
	.alloc		= expkey_alloc,
};

static int
svc_expkey_hash(struct svc_expkey *item)
{
	int hash = item->ek_fsidtype;
	char * cp = (char*)item->ek_fsid;
	int len = key_len(item->ek_fsidtype);

	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
	hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
	hash &= EXPKEY_HASHMASK;
	return hash;
}

static struct svc_expkey *
svc_expkey_lookup(struct cache_detail *cd, struct svc_expkey *item)
{
	struct cache_head *ch;
	int hash = svc_expkey_hash(item);

	ch = sunrpc_cache_lookup(cd, &item->h, hash);
	if (ch)
		return container_of(ch, struct svc_expkey, h);
	else
		return NULL;
}

static struct svc_expkey *
svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new,
		  struct svc_expkey *old)
{
	struct cache_head *ch;
	int hash = svc_expkey_hash(new);

	ch = sunrpc_cache_update(cd, &new->h, &old->h, hash);
	if (ch)
		return container_of(ch, struct svc_expkey, h);
	else
		return NULL;
}


#define	EXPORT_HASHBITS		8
#define	EXPORT_HASHMAX		(1<< EXPORT_HASHBITS)

static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
{
	struct nfsd4_fs_location *locations = fsloc->locations;
	int i;

	if (!locations)
		return;

	for (i = 0; i < fsloc->locations_count; i++) {
		kfree(locations[i].path);
		kfree(locations[i].hosts);
	}

	kfree(locations);
	fsloc->locations = NULL;
}

static void svc_export_put(struct kref *ref)
{
	struct svc_export *exp = container_of(ref, struct svc_export, h.ref);
	path_put(&exp->ex_path);
	auth_domain_put(exp->ex_client);
	nfsd4_fslocs_free(&exp->ex_fslocs);
	kfree(exp->ex_uuid);
	kfree(exp);
}

static void svc_export_request(struct cache_detail *cd,
			       struct cache_head *h,
			       char **bpp, int *blen)
{
	/*  client path */
	struct svc_export *exp = container_of(h, struct svc_export, h);
	char *pth;

	qword_add(bpp, blen, exp->ex_client->name);
	pth = d_path(&exp->ex_path, *bpp, *blen);
	if (IS_ERR(pth)) {
		/* is this correct? */
		(*bpp)[0] = '\n';
		return;
	}
	qword_add(bpp, blen, pth);
	(*bpp)[-1] = '\n';
}

static struct svc_export *svc_export_update(struct svc_export *new,
					    struct svc_export *old);
static struct svc_export *svc_export_lookup(struct svc_export *);

static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
{

	/*
	 * We currently export only dirs, regular files, and (for v4
	 * pseudoroot) symlinks.
	 */
	if (!S_ISDIR(inode->i_mode) &&
	    !S_ISLNK(inode->i_mode) &&
	    !S_ISREG(inode->i_mode))
		return -ENOTDIR;

	/*
	 * Mountd should never pass down a writeable V4ROOT export, but,
	 * just to make sure:
	 */
	if (*flags & NFSEXP_V4ROOT)
		*flags |= NFSEXP_READONLY;

	/* There are two requirements on a filesystem to be exportable.
	 * 1:  We must be able to identify the filesystem from a number.
	 *       either a device number (so FS_REQUIRES_DEV needed)
	 *       or an FSID number (so NFSEXP_FSID or ->uuid is needed).
	 * 2:  We must be able to find an inode from a filehandle.
	 *       This means that s_export_op must be set.
	 */
	if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
	    !(*flags & NFSEXP_FSID) &&
	    uuid == NULL) {
		dprintk("exp_export: export of non-dev fs without fsid\n");
		return -EINVAL;
	}

	if (!inode->i_sb->s_export_op ||
	    !inode->i_sb->s_export_op->fh_to_dentry) {
		dprintk("exp_export: export of invalid fs type.\n");
		return -EINVAL;
	}

	return 0;

}

#ifdef CONFIG_NFSD_V4

static int
fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
{
	int len;
	int migrated, i, err;

	/* more than one fsloc */
	if (fsloc->locations)
		return -EINVAL;

	/* listsize */
	err = get_uint(mesg, &fsloc->locations_count);
	if (err)
		return err;
	if (fsloc->locations_count > MAX_FS_LOCATIONS)
		return -EINVAL;
	if (fsloc->locations_count == 0)
		return 0;

	fsloc->locations = kzalloc(fsloc->locations_count
			* sizeof(struct nfsd4_fs_location), GFP_KERNEL);
	if (!fsloc->locations)
		return -ENOMEM;
	for (i=0; i < fsloc->locations_count; i++) {
		/* colon separated host list */
		err = -EINVAL;
		len = qword_get(mesg, buf, PAGE_SIZE);
		if (len <= 0)
			goto out_free_all;
		err = -ENOMEM;
		fsloc->locations[i].hosts = kstrdup(buf, GFP_KERNEL);
		if (!fsloc->locations[i].hosts)
			goto out_free_all;
		err = -EINVAL;
		/* slash separated path component list */
		len = qword_get(mesg, buf, PAGE_SIZE);
		if (len <= 0)
			goto out_free_all;
		err = -ENOMEM;
		fsloc->locations[i].path = kstrdup(buf, GFP_KERNEL);
		if (!fsloc->locations[i].path)
			goto out_free_all;
	}
	/* migrated */
	err = get_int(mesg, &migrated);
	if (err)
		goto out_free_all;
	err = -EINVAL;
	if (migrated < 0 || migrated > 1)
		goto out_free_all;
	fsloc->migrated = migrated;
	return 0;
out_free_all:
	nfsd4_fslocs_free(fsloc);
	return err;
}

static int secinfo_parse(char **mesg, char *buf, struct svc_export *exp)
{
	struct exp_flavor_info *f;
	u32 listsize;
	int err;

	/* more than one secinfo */
	if (exp->ex_nflavors)
		return -EINVAL;

	err = get_uint(mesg, &listsize);
	if (err)
		return err;
	if (listsize > MAX_SECINFO_LIST)
		return -EINVAL;

	for (f = exp->ex_flavors; f < exp->ex_flavors + listsize; f++) {
		err = get_uint(mesg, &f->pseudoflavor);
		if (err)
			return err;
		/*
		 * XXX: It would be nice to also check whether this
		 * pseudoflavor is supported, so we can discover the
		 * problem at export time instead of when a client fails
		 * to authenticate.
		 */
		err = get_uint(mesg, &f->flags);
		if (err)
			return err;
		/* Only some flags are allowed to differ between flavors: */
		if (~NFSEXP_SECINFO_FLAGS & (f->flags ^ exp->ex_flags))
			return -EINVAL;
	}
	exp->ex_nflavors = listsize;
	return 0;
}

#else /* CONFIG_NFSD_V4 */
static inline int
fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc){return 0;}
static inline int
secinfo_parse(char **mesg, char *buf, struct svc_export *exp) { return 0; }
#endif

static inline int
nfsd_uuid_parse(char **mesg, char *buf, unsigned char **puuid)
{
	int len;

	/* more than one uuid */
	if (*puuid)
		return -EINVAL;

	/* expect a 16 byte uuid encoded as \xXXXX... */
	len = qword_get(mesg, buf, PAGE_SIZE);
	if (len != EX_UUID_LEN)
		return -EINVAL;

	*puuid = kmemdup(buf, EX_UUID_LEN, GFP_KERNEL);
	if (*puuid == NULL)
		return -ENOMEM;

	return 0;
}

static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
{
	/* client path expiry [flags anonuid anongid fsid] */
	char *buf;
	int len;
	int err;
	struct auth_domain *dom = NULL;
	struct svc_export exp = {}, *expp;
	int an_int;

	if (mesg[mlen-1] != '\n')
		return -EINVAL;
	mesg[mlen-1] = 0;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	/* client */
	err = -EINVAL;
	len = qword_get(&mesg, buf, PAGE_SIZE);
	if (len <= 0)
		goto out;

	err = -ENOENT;
	dom = auth_domain_find(buf);
	if (!dom)
		goto out;

	/* path */
	err = -EINVAL;
	if ((len = qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out1;

	err = kern_path(buf, 0, &exp.ex_path);
	if (err)
		goto out1;

	exp.ex_client = dom;
	exp.cd = cd;
	exp.ex_devid_map = NULL;

	/* expiry */
	err = -EINVAL;
	exp.h.expiry_time = get_expiry(&mesg);
	if (exp.h.expiry_time == 0)
		goto out3;

	/* flags */
	err = get_int(&mesg, &an_int);
	if (err == -ENOENT) {
		err = 0;
		set_bit(CACHE_NEGATIVE, &exp.h.flags);
	} else {
		if (err || an_int < 0)
			goto out3;
		exp.ex_flags= an_int;
	
		/* anon uid */
		err = get_int(&mesg, &an_int);
		if (err)
			goto out3;
		exp.ex_anon_uid= make_kuid(&init_user_ns, an_int);

		/* anon gid */
		err = get_int(&mesg, &an_int);
		if (err)
			goto out3;
		exp.ex_anon_gid= make_kgid(&init_user_ns, an_int);

		/* fsid */
		err = get_int(&mesg, &an_int);
		if (err)
			goto out3;
		exp.ex_fsid = an_int;

		while ((len = qword_get(&mesg, buf, PAGE_SIZE)) > 0) {
			if (strcmp(buf, "fsloc") == 0)
				err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
			else if (strcmp(buf, "uuid") == 0)
				err = nfsd_uuid_parse(&mesg, buf, &exp.ex_uuid);
			else if (strcmp(buf, "secinfo") == 0)
				err = secinfo_parse(&mesg, buf, &exp);
			else
				/* quietly ignore unknown words and anything
				 * following. Newer user-space can try to set
				 * new values, then see what the result was.
				 */
				break;
			if (err)
				goto out4;
		}

		err = check_export(d_inode(exp.ex_path.dentry), &exp.ex_flags,
				   exp.ex_uuid);
		if (err)
			goto out4;
		/*
		 * No point caching this if it would immediately expire.
		 * Also, this protects exportfs's dummy export from the
		 * anon_uid/anon_gid checks:
		 */
		if (exp.h.expiry_time < seconds_since_boot())
			goto out4;
		/*
		 * For some reason exportfs has been passing down an
		 * invalid (-1) uid & gid on the "dummy" export which it
		 * uses to test export support.  To make sure exportfs
		 * sees errors from check_export we therefore need to
		 * delay these checks till after check_export:
		 */
		err = -EINVAL;
		if (!uid_valid(exp.ex_anon_uid))
			goto out4;
		if (!gid_valid(exp.ex_anon_gid))
			goto out4;
		err = 0;

		nfsd4_setup_layout_type(&exp);
	}

	expp = svc_export_lookup(&exp);
	if (expp)
		expp = svc_export_update(&exp, expp);
	else
		err = -ENOMEM;
	cache_flush();
	if (expp == NULL)
		err = -ENOMEM;
	else
		exp_put(expp);
out4:
	nfsd4_fslocs_free(&exp.ex_fslocs);
	kfree(exp.ex_uuid);
out3:
	path_put(&exp.ex_path);
out1:
	auth_domain_put(dom);
out:
	kfree(buf);
	return err;
}

static void exp_flags(struct seq_file *m, int flag, int fsid,
		kuid_t anonu, kgid_t anong, struct nfsd4_fs_locations *fslocs);
static void show_secinfo(struct seq_file *m, struct svc_export *exp);

static int svc_export_show(struct seq_file *m,
			   struct cache_detail *cd,
			   struct cache_head *h)
{
	struct svc_export *exp ;

	if (h ==NULL) {
		seq_puts(m, "#path domain(flags)\n");
		return 0;
	}
	exp = container_of(h, struct svc_export, h);
	seq_path(m, &exp->ex_path, " \t\n\\");
	seq_putc(m, '\t');
	seq_escape(m, exp->ex_client->name, " \t\n\\");
	seq_putc(m, '(');
	if (test_bit(CACHE_VALID, &h->flags) && 
	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
		exp_flags(m, exp->ex_flags, exp->ex_fsid,
			  exp->ex_anon_uid, exp->ex_anon_gid, &exp->ex_fslocs);
		if (exp->ex_uuid) {
			int i;
			seq_puts(m, ",uuid=");
			for (i = 0; i < EX_UUID_LEN; i++) {
				if ((i&3) == 0 && i)
					seq_putc(m, ':');
				seq_printf(m, "%02x", exp->ex_uuid[i]);
			}
		}
		show_secinfo(m, exp);
	}
	seq_puts(m, ")\n");
	return 0;
}
static int svc_export_match(struct cache_head *a, struct cache_head *b)
{
	struct svc_export *orig = container_of(a, struct svc_export, h);
	struct svc_export *new = container_of(b, struct svc_export, h);
	return orig->ex_client == new->ex_client &&
		path_equal(&orig->ex_path, &new->ex_path);
}

static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
{
	struct svc_export *new = container_of(cnew, struct svc_export, h);
	struct svc_export *item = container_of(citem, struct svc_export, h);

	kref_get(&item->ex_client->ref);
	new->ex_client = item->ex_client;
	new->ex_path = item->ex_path;
	path_get(&item->ex_path);
	new->ex_fslocs.locations = NULL;
	new->ex_fslocs.locations_count = 0;
	new->ex_fslocs.migrated = 0;
	new->ex_layout_types = 0;
	new->ex_uuid = NULL;
	new->cd = item->cd;
}

static void export_update(struct cache_head *cnew, struct cache_head *citem)
{
	struct svc_export *new = container_of(cnew, struct svc_export, h);
	struct svc_export *item = container_of(citem, struct svc_export, h);
	int i;

	new->ex_flags = item->ex_flags;
	new->ex_anon_uid = item->ex_anon_uid;
	new->ex_anon_gid = item->ex_anon_gid;
	new->ex_fsid = item->ex_fsid;
	new->ex_devid_map = item->ex_devid_map;
	item->ex_devid_map = NULL;
	new->ex_uuid = item->ex_uuid;
	item->ex_uuid = NULL;
	new->ex_fslocs.locations = item->ex_fslocs.locations;
	item->ex_fslocs.locations = NULL;
	new->ex_fslocs.locations_count = item->ex_fslocs.locations_count;
	item->ex_fslocs.locations_count = 0;
	new->ex_fslocs.migrated = item->ex_fslocs.migrated;
	item->ex_fslocs.migrated = 0;
	new->ex_layout_types = item->ex_layout_types;
	new->ex_nflavors = item->ex_nflavors;
	for (i = 0; i < MAX_SECINFO_LIST; i++) {
		new->ex_flavors[i] = item->ex_flavors[i];
	}
}

static struct cache_head *svc_export_alloc(void)
{
	struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL);
	if (i)
		return &i->h;
	else
		return NULL;
}

static struct cache_detail svc_export_cache_template = {
	.owner		= THIS_MODULE,
	.hash_size	= EXPORT_HASHMAX,
	.name		= "nfsd.export",
	.cache_put	= svc_export_put,
	.cache_request	= svc_export_request,
	.cache_parse	= svc_export_parse,
	.cache_show	= svc_export_show,
	.match		= svc_export_match,
	.init		= svc_export_init,
	.update		= export_update,
	.alloc		= svc_export_alloc,
};

static int
svc_export_hash(struct svc_export *exp)
{
	int hash;

	hash = hash_ptr(exp->ex_client, EXPORT_HASHBITS);
	hash ^= hash_ptr(exp->ex_path.dentry, EXPORT_HASHBITS);
	hash ^= hash_ptr(exp->ex_path.mnt, EXPORT_HASHBITS);
	return hash;
}

static struct svc_export *
svc_export_lookup(struct svc_export *exp)
{
	struct cache_head *ch;
	int hash = svc_export_hash(exp);

	ch = sunrpc_cache_lookup(exp->cd, &exp->h, hash);
	if (ch)
		return container_of(ch, struct svc_export, h);
	else
		return NULL;
}

static struct svc_export *
svc_export_update(struct svc_export *new, struct svc_export *old)
{
	struct cache_head *ch;
	int hash = svc_export_hash(old);

	ch = sunrpc_cache_update(old->cd, &new->h, &old->h, hash);
	if (ch)
		return container_of(ch, struct svc_export, h);
	else
		return NULL;
}


static struct svc_expkey *
exp_find_key(struct cache_detail *cd, struct auth_domain *clp, int fsid_type,
	     u32 *fsidv, struct cache_req *reqp)
{
	struct svc_expkey key, *ek;
	int err;
	
	if (!clp)
		return ERR_PTR(-ENOENT);

	key.ek_client = clp;
	key.ek_fsidtype = fsid_type;
	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));

	ek = svc_expkey_lookup(cd, &key);
	if (ek == NULL)
		return ERR_PTR(-ENOMEM);
	err = cache_check(cd, &ek->h, reqp);
	if (err)
		return ERR_PTR(err);
	return ek;
}

static struct svc_export *
exp_get_by_name(struct cache_detail *cd, struct auth_domain *clp,
		const struct path *path, struct cache_req *reqp)
{
	struct svc_export *exp, key;
	int err;

	if (!clp)
		return ERR_PTR(-ENOENT);

	key.ex_client = clp;
	key.ex_path = *path;
	key.cd = cd;

	exp = svc_export_lookup(&key);
	if (exp == NULL)
		return ERR_PTR(-ENOMEM);
	err = cache_check(cd, &exp->h, reqp);
	if (err)
		return ERR_PTR(err);
	return exp;
}

/*
 * Find the export entry for a given dentry.
 */
static struct svc_export *
exp_parent(struct cache_detail *cd, struct auth_domain *clp, struct path *path)
{
	struct dentry *saved = dget(path->dentry);
	struct svc_export *exp = exp_get_by_name(cd, clp, path, NULL);

	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(path->dentry)) {
		struct dentry *parent = dget_parent(path->dentry);
		dput(path->dentry);
		path->dentry = parent;
		exp = exp_get_by_name(cd, clp, path, NULL);
	}
	dput(path->dentry);
	path->dentry = saved;
	return exp;
}



/*
 * Obtain the root fh on behalf of a client.
 * This could be done in user space, but I feel that it adds some safety
 * since its harder to fool a kernel module than a user space program.
 */
int
exp_rootfh(struct net *net, struct auth_domain *clp, char *name,
	   struct knfsd_fh *f, int maxsize)
{
	struct svc_export	*exp;
	struct path		path;
	struct inode		*inode;
	struct svc_fh		fh;
	int			err;
	struct nfsd_net		*nn = net_generic(net, nfsd_net_id);
	struct cache_detail	*cd = nn->svc_export_cache;

	err = -EPERM;
	/* NB: we probably ought to check that it's NUL-terminated */
	if (kern_path(name, 0, &path)) {
		printk("nfsd: exp_rootfh path not found %s", name);
		return err;
	}
	inode = d_inode(path.dentry);

	dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)\n",
		 name, path.dentry, clp->name,
		 inode->i_sb->s_id, inode->i_ino);
	exp = exp_parent(cd, clp, &path);
	if (IS_ERR(exp)) {
		err = PTR_ERR(exp);
		goto out;
	}

	/*
	 * fh must be initialized before calling fh_compose
	 */
	fh_init(&fh, maxsize);
	if (fh_compose(&fh, exp, path.dentry, NULL))
		err = -EINVAL;
	else
		err = 0;
	memcpy(f, &fh.fh_handle, sizeof(struct knfsd_fh));
	fh_put(&fh);
	exp_put(exp);
out:
	path_put(&path);
	return err;
}

static struct svc_export *exp_find(struct cache_detail *cd,
				   struct auth_domain *clp, int fsid_type,
				   u32 *fsidv, struct cache_req *reqp)
{
	struct svc_export *exp;
	struct nfsd_net *nn = net_generic(cd->net, nfsd_net_id);
	struct svc_expkey *ek = exp_find_key(nn->svc_expkey_cache, clp, fsid_type, fsidv, reqp);
	if (IS_ERR(ek))
		return ERR_CAST(ek);

	exp = exp_get_by_name(cd, clp, &ek->ek_path, reqp);
	cache_put(&ek->h, nn->svc_expkey_cache);

	if (IS_ERR(exp))
		return ERR_CAST(exp);
	return exp;
}

__be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
{
	struct exp_flavor_info *f;
	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;

	/* legacy gss-only clients are always OK: */
	if (exp->ex_client == rqstp->rq_gssclient)
		return 0;
	/* ip-address based client; check sec= export option: */
	for (f = exp->ex_flavors; f < end; f++) {
		if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
			return 0;
	}
	/* defaults in absence of sec= options: */
	if (exp->ex_nflavors == 0) {
		if (rqstp->rq_cred.cr_flavor == RPC_AUTH_NULL ||
		    rqstp->rq_cred.cr_flavor == RPC_AUTH_UNIX)
			return 0;
	}

	/* If the compound op contains a spo_must_allowed op,
	 * it will be sent with integrity/protection which
	 * will have to be expressly allowed on mounts that
	 * don't support it
	 */

	if (nfsd4_spo_must_allow(rqstp))
		return 0;

	return nfserr_wrongsec;
}

/*
 * Uses rq_client and rq_gssclient to find an export; uses rq_client (an
 * auth_unix client) if it's available and has secinfo information;
 * otherwise, will try to use rq_gssclient.
 *
 * Called from functions that handle requests; functions that do work on
 * behalf of mountd are passed a single client name to use, and should
 * use exp_get_by_name() or exp_find().
 */
struct svc_export *
rqst_exp_get_by_name(struct svc_rqst *rqstp, struct path *path)
{
	struct svc_export *gssexp, *exp = ERR_PTR(-ENOENT);
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
	struct cache_detail *cd = nn->svc_export_cache;

	if (rqstp->rq_client == NULL)
		goto gss;

	/* First try the auth_unix client: */
	exp = exp_get_by_name(cd, rqstp->rq_client, path, &rqstp->rq_chandle);
	if (PTR_ERR(exp) == -ENOENT)
		goto gss;
	if (IS_ERR(exp))
		return exp;
	/* If it has secinfo, assume there are no gss/... clients */
	if (exp->ex_nflavors > 0)
		return exp;
gss:
	/* Otherwise, try falling back on gss client */
	if (rqstp->rq_gssclient == NULL)
		return exp;
	gssexp = exp_get_by_name(cd, rqstp->rq_gssclient, path, &rqstp->rq_chandle);
	if (PTR_ERR(gssexp) == -ENOENT)
		return exp;
	if (!IS_ERR(exp))
		exp_put(exp);
	return gssexp;
}

struct svc_export *
rqst_exp_find(struct svc_rqst *rqstp, int fsid_type, u32 *fsidv)
{
	struct svc_export *gssexp, *exp = ERR_PTR(-ENOENT);
	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
	struct cache_detail *cd = nn->svc_export_cache;

	if (rqstp->rq_client == NULL)
		goto gss;

	/* First try the auth_unix client: */
	exp = exp_find(cd, rqstp->rq_client, fsid_type,
		       fsidv, &rqstp->rq_chandle);
	if (PTR_ERR(exp) == -ENOENT)
		goto gss;
	if (IS_ERR(exp))
		return exp;
	/* If it has secinfo, assume there are no gss/... clients */
	if (exp->ex_nflavors > 0)
		return exp;
gss:
	/* Otherwise, try falling back on gss client */
	if (rqstp->rq_gssclient == NULL)
		return exp;
	gssexp = exp_find(cd, rqstp->rq_gssclient, fsid_type, fsidv,
						&rqstp->rq_chandle);
	if (PTR_ERR(gssexp) == -ENOENT)
		return exp;
	if (!IS_ERR(exp))
		exp_put(exp);
	return gssexp;
}

struct svc_export *
rqst_exp_parent(struct svc_rqst *rqstp, struct path *path)
{
	struct dentry *saved = dget(path->dentry);
	struct svc_export *exp = rqst_exp_get_by_name(rqstp, path);

	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(path->dentry)) {
		struct dentry *parent = dget_parent(path->dentry);
		dput(path->dentry);
		path->dentry = parent;
		exp = rqst_exp_get_by_name(rqstp, path);
	}
	dput(path->dentry);
	path->dentry = saved;
	return exp;
}

struct svc_export *rqst_find_fsidzero_export(struct svc_rqst *rqstp)
{
	u32 fsidv[2];

	mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);

	return rqst_exp_find(rqstp, FSID_NUM, fsidv);
}

/*
 * Called when we need the filehandle for the root of the pseudofs,
 * for a given NFSv4 client.   The root is defined to be the
 * export point with fsid==0
 */
__be32
exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
{
	struct svc_export *exp;
	__be32 rv;

	exp = rqst_find_fsidzero_export(rqstp);
	if (IS_ERR(exp))
		return nfserrno(PTR_ERR(exp));
	rv = fh_compose(fhp, exp, exp->ex_path.dentry, NULL);
	exp_put(exp);
	return rv;
}

static struct flags {
	int flag;
	char *name[2];
} expflags[] = {
	{ NFSEXP_READONLY, {"ro", "rw"}},
	{ NFSEXP_INSECURE_PORT, {"insecure", ""}},
	{ NFSEXP_ROOTSQUASH, {"root_squash", "no_root_squash"}},
	{ NFSEXP_ALLSQUASH, {"all_squash", ""}},
	{ NFSEXP_ASYNC, {"async", "sync"}},
	{ NFSEXP_GATHERED_WRITES, {"wdelay", "no_wdelay"}},
	{ NFSEXP_NOREADDIRPLUS, {"nordirplus", ""}},
	{ NFSEXP_NOHIDE, {"nohide", ""}},
	{ NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
	{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
	{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
	{ NFSEXP_V4ROOT, {"v4root", ""}},
	{ NFSEXP_PNFS, {"pnfs", ""}},
	{ NFSEXP_SECURITY_LABEL, {"security_label", ""}},
	{ 0, {"", ""}}
};

static void show_expflags(struct seq_file *m, int flags, int mask)
{
	struct flags *flg;
	int state, first = 0;

	for (flg = expflags; flg->flag; flg++) {
		if (flg->flag & ~mask)
			continue;
		state = (flg->flag & flags) ? 0 : 1;
		if (*flg->name[state])
			seq_printf(m, "%s%s", first++?",":"", flg->name[state]);
	}
}

static void show_secinfo_flags(struct seq_file *m, int flags)
{
	seq_printf(m, ",");
	show_expflags(m, flags, NFSEXP_SECINFO_FLAGS);
}

static bool secinfo_flags_equal(int f, int g)
{
	f &= NFSEXP_SECINFO_FLAGS;
	g &= NFSEXP_SECINFO_FLAGS;
	return f == g;
}

static int show_secinfo_run(struct seq_file *m, struct exp_flavor_info **fp, struct exp_flavor_info *end)
{
	int flags;

	flags = (*fp)->flags;
	seq_printf(m, ",sec=%d", (*fp)->pseudoflavor);
	(*fp)++;
	while (*fp != end && secinfo_flags_equal(flags, (*fp)->flags)) {
		seq_printf(m, ":%d", (*fp)->pseudoflavor);
		(*fp)++;
	}
	return flags;
}

static void show_secinfo(struct seq_file *m, struct svc_export *exp)
{
	struct exp_flavor_info *f;
	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
	int flags;

	if (exp->ex_nflavors == 0)
		return;
	f = exp->ex_flavors;
	flags = show_secinfo_run(m, &f, end);
	if (!secinfo_flags_equal(flags, exp->ex_flags))
		show_secinfo_flags(m, flags);
	while (f != end) {
		flags = show_secinfo_run(m, &f, end);
		show_secinfo_flags(m, flags);
	}
}

static void exp_flags(struct seq_file *m, int flag, int fsid,
		kuid_t anonu, kgid_t anong, struct nfsd4_fs_locations *fsloc)
{
	show_expflags(m, flag, NFSEXP_ALLFLAGS);
	if (flag & NFSEXP_FSID)
		seq_printf(m, ",fsid=%d", fsid);
	if (!uid_eq(anonu, make_kuid(&init_user_ns, (uid_t)-2)) &&
	    !uid_eq(anonu, make_kuid(&init_user_ns, 0x10000-2)))
		seq_printf(m, ",anonuid=%u", from_kuid(&init_user_ns, anonu));
	if (!gid_eq(anong, make_kgid(&init_user_ns, (gid_t)-2)) &&
	    !gid_eq(anong, make_kgid(&init_user_ns, 0x10000-2)))
		seq_printf(m, ",anongid=%u", from_kgid(&init_user_ns, anong));
	if (fsloc && fsloc->locations_count > 0) {
		char *loctype = (fsloc->migrated) ? "refer" : "replicas";
		int i;

		seq_printf(m, ",%s=", loctype);
		seq_escape(m, fsloc->locations[0].path, ",;@ \t\n\\");
		seq_putc(m, '@');
		seq_escape(m, fsloc->locations[0].hosts, ",;@ \t\n\\");
		for (i = 1; i < fsloc->locations_count; i++) {
			seq_putc(m, ';');
			seq_escape(m, fsloc->locations[i].path, ",;@ \t\n\\");
			seq_putc(m, '@');
			seq_escape(m, fsloc->locations[i].hosts, ",;@ \t\n\\");
		}
	}
}

static int e_show(struct seq_file *m, void *p)
{
	struct cache_head *cp = p;
	struct svc_export *exp = container_of(cp, struct svc_export, h);
	struct cache_detail *cd = m->private;

	if (p == SEQ_START_TOKEN) {
		seq_puts(m, "# Version 1.1\n");
		seq_puts(m, "# Path Client(Flags) # IPs\n");
		return 0;
	}

	exp_get(exp);
	if (cache_check(cd, &exp->h, NULL))
		return 0;
	exp_put(exp);
	return svc_export_show(m, cd, cp);
}

const struct seq_operations nfs_exports_op = {
	.start	= cache_seq_start,
	.next	= cache_seq_next,
	.stop	= cache_seq_stop,
	.show	= e_show,
};

/*
 * Initialize the exports module.
 */
int
nfsd_export_init(struct net *net)
{
	int rv;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	dprintk("nfsd: initializing export module (net: %p).\n", net);

	nn->svc_export_cache = cache_create_net(&svc_export_cache_template, net);
	if (IS_ERR(nn->svc_export_cache))
		return PTR_ERR(nn->svc_export_cache);
	rv = cache_register_net(nn->svc_export_cache, net);
	if (rv)
		goto destroy_export_cache;

	nn->svc_expkey_cache = cache_create_net(&svc_expkey_cache_template, net);
	if (IS_ERR(nn->svc_expkey_cache)) {
		rv = PTR_ERR(nn->svc_expkey_cache);
		goto unregister_export_cache;
	}
	rv = cache_register_net(nn->svc_expkey_cache, net);
	if (rv)
		goto destroy_expkey_cache;
	return 0;

destroy_expkey_cache:
	cache_destroy_net(nn->svc_expkey_cache, net);
unregister_export_cache:
	cache_unregister_net(nn->svc_export_cache, net);
destroy_export_cache:
	cache_destroy_net(nn->svc_export_cache, net);
	return rv;
}

/*
 * Flush exports table - called when last nfsd thread is killed
 */
void
nfsd_export_flush(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	cache_purge(nn->svc_expkey_cache);
	cache_purge(nn->svc_export_cache);
}

/*
 * Shutdown the exports module.
 */
void
nfsd_export_shutdown(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	dprintk("nfsd: shutting down export module (net: %p).\n", net);

	cache_unregister_net(nn->svc_expkey_cache, net);
	cache_unregister_net(nn->svc_export_cache, net);
	cache_destroy_net(nn->svc_expkey_cache, net);
	cache_destroy_net(nn->svc_export_cache, net);
	svcauth_unix_purge(net);

	dprintk("nfsd: export shutdown complete (net: %p).\n", net);
}