xref: /openbmc/linux/fs/nfsd/export.c (revision 32c1eb0cd7ee00b5eb7b6f7059c635fbc1052966)
1 #define MSNFS	/* HACK HACK */
2 /*
3  * linux/fs/nfsd/export.c
4  *
5  * NFS exporting and validation.
6  *
7  * We maintain a list of clients, each of which has a list of
8  * exports. To export an fs to a given client, you first have
9  * to create the client entry with NFSCTL_ADDCLIENT, which
10  * creates a client control block and adds it to the hash
11  * table. Then, you call NFSCTL_EXPORT for each fs.
12  *
13  *
14  * Copyright (C) 1995, 1996 Olaf Kirch, <okir@monad.swb.de>
15  */
16 
17 #include <linux/unistd.h>
18 #include <linux/slab.h>
19 #include <linux/stat.h>
20 #include <linux/in.h>
21 #include <linux/seq_file.h>
22 #include <linux/syscalls.h>
23 #include <linux/rwsem.h>
24 #include <linux/dcache.h>
25 #include <linux/namei.h>
26 #include <linux/mount.h>
27 #include <linux/hash.h>
28 #include <linux/module.h>
29 #include <linux/exportfs.h>
30 
31 #include <linux/sunrpc/svc.h>
32 #include <linux/nfsd/nfsd.h>
33 #include <linux/nfsd/nfsfh.h>
34 #include <linux/nfsd/syscall.h>
35 #include <linux/lockd/bind.h>
36 #include <linux/sunrpc/msg_prot.h>
37 #include <linux/sunrpc/gss_api.h>
38 
39 #define NFSDDBG_FACILITY	NFSDDBG_EXPORT
40 
41 typedef struct auth_domain	svc_client;
42 typedef struct svc_export	svc_export;
43 
44 static void		exp_do_unexport(svc_export *unexp);
45 static int		exp_verify_string(char *cp, int max);
46 
47 /*
48  * We have two caches.
49  * One maps client+vfsmnt+dentry to export options - the export map
50  * The other maps client+filehandle-fragment to export options. - the expkey map
51  *
52  * The export options are actually stored in the first map, and the
53  * second map contains a reference to the entry in the first map.
54  */
55 
56 #define	EXPKEY_HASHBITS		8
57 #define	EXPKEY_HASHMAX		(1 << EXPKEY_HASHBITS)
58 #define	EXPKEY_HASHMASK		(EXPKEY_HASHMAX -1)
59 static struct cache_head *expkey_table[EXPKEY_HASHMAX];
60 
61 static void expkey_put(struct kref *ref)
62 {
63 	struct svc_expkey *key = container_of(ref, struct svc_expkey, h.ref);
64 
65 	if (test_bit(CACHE_VALID, &key->h.flags) &&
66 	    !test_bit(CACHE_NEGATIVE, &key->h.flags)) {
67 		dput(key->ek_dentry);
68 		mntput(key->ek_mnt);
69 	}
70 	auth_domain_put(key->ek_client);
71 	kfree(key);
72 }
73 
74 static void expkey_request(struct cache_detail *cd,
75 			   struct cache_head *h,
76 			   char **bpp, int *blen)
77 {
78 	/* client fsidtype \xfsid */
79 	struct svc_expkey *ek = container_of(h, struct svc_expkey, h);
80 	char type[5];
81 
82 	qword_add(bpp, blen, ek->ek_client->name);
83 	snprintf(type, 5, "%d", ek->ek_fsidtype);
84 	qword_add(bpp, blen, type);
85 	qword_addhex(bpp, blen, (char*)ek->ek_fsid, key_len(ek->ek_fsidtype));
86 	(*bpp)[-1] = '\n';
87 }
88 
89 static struct svc_expkey *svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old);
90 static struct svc_expkey *svc_expkey_lookup(struct svc_expkey *);
91 static struct cache_detail svc_expkey_cache;
92 
93 static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
94 {
95 	/* client fsidtype fsid [path] */
96 	char *buf;
97 	int len;
98 	struct auth_domain *dom = NULL;
99 	int err;
100 	int fsidtype;
101 	char *ep;
102 	struct svc_expkey key;
103 	struct svc_expkey *ek;
104 
105 	if (mesg[mlen-1] != '\n')
106 		return -EINVAL;
107 	mesg[mlen-1] = 0;
108 
109 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
110 	err = -ENOMEM;
111 	if (!buf) goto out;
112 
113 	err = -EINVAL;
114 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
115 		goto out;
116 
117 	err = -ENOENT;
118 	dom = auth_domain_find(buf);
119 	if (!dom)
120 		goto out;
121 	dprintk("found domain %s\n", buf);
122 
123 	err = -EINVAL;
124 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
125 		goto out;
126 	fsidtype = simple_strtoul(buf, &ep, 10);
127 	if (*ep)
128 		goto out;
129 	dprintk("found fsidtype %d\n", fsidtype);
130 	if (key_len(fsidtype)==0) /* invalid type */
131 		goto out;
132 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
133 		goto out;
134 	dprintk("found fsid length %d\n", len);
135 	if (len != key_len(fsidtype))
136 		goto out;
137 
138 	/* OK, we seem to have a valid key */
139 	key.h.flags = 0;
140 	key.h.expiry_time = get_expiry(&mesg);
141 	if (key.h.expiry_time == 0)
142 		goto out;
143 
144 	key.ek_client = dom;
145 	key.ek_fsidtype = fsidtype;
146 	memcpy(key.ek_fsid, buf, len);
147 
148 	ek = svc_expkey_lookup(&key);
149 	err = -ENOMEM;
150 	if (!ek)
151 		goto out;
152 
153 	/* now we want a pathname, or empty meaning NEGATIVE  */
154 	err = -EINVAL;
155 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) < 0)
156 		goto out;
157 	dprintk("Path seems to be <%s>\n", buf);
158 	err = 0;
159 	if (len == 0) {
160 		set_bit(CACHE_NEGATIVE, &key.h.flags);
161 		ek = svc_expkey_update(&key, ek);
162 		if (ek)
163 			cache_put(&ek->h, &svc_expkey_cache);
164 		else err = -ENOMEM;
165 	} else {
166 		struct nameidata nd;
167 		err = path_lookup(buf, 0, &nd);
168 		if (err)
169 			goto out;
170 
171 		dprintk("Found the path %s\n", buf);
172 		key.ek_mnt = nd.mnt;
173 		key.ek_dentry = nd.dentry;
174 
175 		ek = svc_expkey_update(&key, ek);
176 		if (ek)
177 			cache_put(&ek->h, &svc_expkey_cache);
178 		else
179 			err = -ENOMEM;
180 		path_release(&nd);
181 	}
182 	cache_flush();
183  out:
184 	if (dom)
185 		auth_domain_put(dom);
186 	kfree(buf);
187 	return err;
188 }
189 
190 static int expkey_show(struct seq_file *m,
191 		       struct cache_detail *cd,
192 		       struct cache_head *h)
193 {
194 	struct svc_expkey *ek ;
195 	int i;
196 
197 	if (h ==NULL) {
198 		seq_puts(m, "#domain fsidtype fsid [path]\n");
199 		return 0;
200 	}
201 	ek = container_of(h, struct svc_expkey, h);
202 	seq_printf(m, "%s %d 0x", ek->ek_client->name,
203 		   ek->ek_fsidtype);
204 	for (i=0; i < key_len(ek->ek_fsidtype)/4; i++)
205 		seq_printf(m, "%08x", ek->ek_fsid[i]);
206 	if (test_bit(CACHE_VALID, &h->flags) &&
207 	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
208 		seq_printf(m, " ");
209 		seq_path(m, ek->ek_mnt, ek->ek_dentry, "\\ \t\n");
210 	}
211 	seq_printf(m, "\n");
212 	return 0;
213 }
214 
215 static inline int expkey_match (struct cache_head *a, struct cache_head *b)
216 {
217 	struct svc_expkey *orig = container_of(a, struct svc_expkey, h);
218 	struct svc_expkey *new = container_of(b, struct svc_expkey, h);
219 
220 	if (orig->ek_fsidtype != new->ek_fsidtype ||
221 	    orig->ek_client != new->ek_client ||
222 	    memcmp(orig->ek_fsid, new->ek_fsid, key_len(orig->ek_fsidtype)) != 0)
223 		return 0;
224 	return 1;
225 }
226 
227 static inline void expkey_init(struct cache_head *cnew,
228 				   struct cache_head *citem)
229 {
230 	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
231 	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);
232 
233 	kref_get(&item->ek_client->ref);
234 	new->ek_client = item->ek_client;
235 	new->ek_fsidtype = item->ek_fsidtype;
236 
237 	memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid));
238 }
239 
240 static inline void expkey_update(struct cache_head *cnew,
241 				   struct cache_head *citem)
242 {
243 	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
244 	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);
245 
246 	new->ek_mnt = mntget(item->ek_mnt);
247 	new->ek_dentry = dget(item->ek_dentry);
248 }
249 
250 static struct cache_head *expkey_alloc(void)
251 {
252 	struct svc_expkey *i = kmalloc(sizeof(*i), GFP_KERNEL);
253 	if (i)
254 		return &i->h;
255 	else
256 		return NULL;
257 }
258 
259 static struct cache_detail svc_expkey_cache = {
260 	.owner		= THIS_MODULE,
261 	.hash_size	= EXPKEY_HASHMAX,
262 	.hash_table	= expkey_table,
263 	.name		= "nfsd.fh",
264 	.cache_put	= expkey_put,
265 	.cache_request	= expkey_request,
266 	.cache_parse	= expkey_parse,
267 	.cache_show	= expkey_show,
268 	.match		= expkey_match,
269 	.init		= expkey_init,
270 	.update       	= expkey_update,
271 	.alloc		= expkey_alloc,
272 };
273 
274 static struct svc_expkey *
275 svc_expkey_lookup(struct svc_expkey *item)
276 {
277 	struct cache_head *ch;
278 	int hash = item->ek_fsidtype;
279 	char * cp = (char*)item->ek_fsid;
280 	int len = key_len(item->ek_fsidtype);
281 
282 	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
283 	hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
284 	hash &= EXPKEY_HASHMASK;
285 
286 	ch = sunrpc_cache_lookup(&svc_expkey_cache, &item->h,
287 				 hash);
288 	if (ch)
289 		return container_of(ch, struct svc_expkey, h);
290 	else
291 		return NULL;
292 }
293 
294 static struct svc_expkey *
295 svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old)
296 {
297 	struct cache_head *ch;
298 	int hash = new->ek_fsidtype;
299 	char * cp = (char*)new->ek_fsid;
300 	int len = key_len(new->ek_fsidtype);
301 
302 	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
303 	hash ^= hash_ptr(new->ek_client, EXPKEY_HASHBITS);
304 	hash &= EXPKEY_HASHMASK;
305 
306 	ch = sunrpc_cache_update(&svc_expkey_cache, &new->h,
307 				 &old->h, hash);
308 	if (ch)
309 		return container_of(ch, struct svc_expkey, h);
310 	else
311 		return NULL;
312 }
313 
314 
315 #define	EXPORT_HASHBITS		8
316 #define	EXPORT_HASHMAX		(1<< EXPORT_HASHBITS)
317 #define	EXPORT_HASHMASK		(EXPORT_HASHMAX -1)
318 
319 static struct cache_head *export_table[EXPORT_HASHMAX];
320 
321 static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
322 {
323 	int i;
324 
325 	for (i = 0; i < fsloc->locations_count; i++) {
326 		kfree(fsloc->locations[i].path);
327 		kfree(fsloc->locations[i].hosts);
328 	}
329 	kfree(fsloc->locations);
330 }
331 
332 static void svc_export_put(struct kref *ref)
333 {
334 	struct svc_export *exp = container_of(ref, struct svc_export, h.ref);
335 	dput(exp->ex_dentry);
336 	mntput(exp->ex_mnt);
337 	auth_domain_put(exp->ex_client);
338 	kfree(exp->ex_path);
339 	nfsd4_fslocs_free(&exp->ex_fslocs);
340 	kfree(exp);
341 }
342 
343 static void svc_export_request(struct cache_detail *cd,
344 			       struct cache_head *h,
345 			       char **bpp, int *blen)
346 {
347 	/*  client path */
348 	struct svc_export *exp = container_of(h, struct svc_export, h);
349 	char *pth;
350 
351 	qword_add(bpp, blen, exp->ex_client->name);
352 	pth = d_path(exp->ex_dentry, exp->ex_mnt, *bpp, *blen);
353 	if (IS_ERR(pth)) {
354 		/* is this correct? */
355 		(*bpp)[0] = '\n';
356 		return;
357 	}
358 	qword_add(bpp, blen, pth);
359 	(*bpp)[-1] = '\n';
360 }
361 
362 static struct svc_export *svc_export_update(struct svc_export *new,
363 					    struct svc_export *old);
364 static struct svc_export *svc_export_lookup(struct svc_export *);
365 
366 static int check_export(struct inode *inode, int flags, unsigned char *uuid)
367 {
368 
369 	/* We currently export only dirs and regular files.
370 	 * This is what umountd does.
371 	 */
372 	if (!S_ISDIR(inode->i_mode) &&
373 	    !S_ISREG(inode->i_mode))
374 		return -ENOTDIR;
375 
376 	/* There are two requirements on a filesystem to be exportable.
377 	 * 1:  We must be able to identify the filesystem from a number.
378 	 *       either a device number (so FS_REQUIRES_DEV needed)
379 	 *       or an FSID number (so NFSEXP_FSID or ->uuid is needed).
380 	 * 2:  We must be able to find an inode from a filehandle.
381 	 *       This means that s_export_op must be set.
382 	 */
383 	if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
384 	    !(flags & NFSEXP_FSID) &&
385 	    uuid == NULL) {
386 		dprintk("exp_export: export of non-dev fs without fsid\n");
387 		return -EINVAL;
388 	}
389 	if (!inode->i_sb->s_export_op) {
390 		dprintk("exp_export: export of invalid fs type.\n");
391 		return -EINVAL;
392 	}
393 
394 	/* Ok, we can export it */;
395 	if (!inode->i_sb->s_export_op->find_exported_dentry)
396 		inode->i_sb->s_export_op->find_exported_dentry =
397 			find_exported_dentry;
398 	return 0;
399 
400 }
401 
402 #ifdef CONFIG_NFSD_V4
403 
404 static int
405 fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
406 {
407 	int len;
408 	int migrated, i, err;
409 
410 	/* listsize */
411 	err = get_int(mesg, &fsloc->locations_count);
412 	if (err)
413 		return err;
414 	if (fsloc->locations_count > MAX_FS_LOCATIONS)
415 		return -EINVAL;
416 	if (fsloc->locations_count == 0)
417 		return 0;
418 
419 	fsloc->locations = kzalloc(fsloc->locations_count
420 			* sizeof(struct nfsd4_fs_location), GFP_KERNEL);
421 	if (!fsloc->locations)
422 		return -ENOMEM;
423 	for (i=0; i < fsloc->locations_count; i++) {
424 		/* colon separated host list */
425 		err = -EINVAL;
426 		len = qword_get(mesg, buf, PAGE_SIZE);
427 		if (len <= 0)
428 			goto out_free_all;
429 		err = -ENOMEM;
430 		fsloc->locations[i].hosts = kstrdup(buf, GFP_KERNEL);
431 		if (!fsloc->locations[i].hosts)
432 			goto out_free_all;
433 		err = -EINVAL;
434 		/* slash separated path component list */
435 		len = qword_get(mesg, buf, PAGE_SIZE);
436 		if (len <= 0)
437 			goto out_free_all;
438 		err = -ENOMEM;
439 		fsloc->locations[i].path = kstrdup(buf, GFP_KERNEL);
440 		if (!fsloc->locations[i].path)
441 			goto out_free_all;
442 	}
443 	/* migrated */
444 	err = get_int(mesg, &migrated);
445 	if (err)
446 		goto out_free_all;
447 	err = -EINVAL;
448 	if (migrated < 0 || migrated > 1)
449 		goto out_free_all;
450 	fsloc->migrated = migrated;
451 	return 0;
452 out_free_all:
453 	nfsd4_fslocs_free(fsloc);
454 	return err;
455 }
456 
457 static int secinfo_parse(char **mesg, char *buf, struct svc_export *exp)
458 {
459 	int listsize, err;
460 	struct exp_flavor_info *f;
461 
462 	err = get_int(mesg, &listsize);
463 	if (err)
464 		return err;
465 	if (listsize < 0 || listsize > MAX_SECINFO_LIST)
466 		return -EINVAL;
467 
468 	for (f = exp->ex_flavors; f < exp->ex_flavors + listsize; f++) {
469 		err = get_int(mesg, &f->pseudoflavor);
470 		if (err)
471 			return err;
472 		/*
473 		 * Just a quick sanity check; we could also try to check
474 		 * whether this pseudoflavor is supported, but at worst
475 		 * an unsupported pseudoflavor on the export would just
476 		 * be a pseudoflavor that won't match the flavor of any
477 		 * authenticated request.  The administrator will
478 		 * probably discover the problem when someone fails to
479 		 * authenticate.
480 		 */
481 		if (f->pseudoflavor < 0)
482 			return -EINVAL;
483 		err = get_int(mesg, &f->flags);
484 		if (err)
485 			return err;
486 		/* Only some flags are allowed to differ between flavors: */
487 		if (~NFSEXP_SECINFO_FLAGS & (f->flags ^ exp->ex_flags))
488 			return -EINVAL;
489 	}
490 	exp->ex_nflavors = listsize;
491 	return 0;
492 }
493 
494 #else /* CONFIG_NFSD_V4 */
495 static inline int
496 fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc){return 0;}
497 static inline int
498 secinfo_parse(char **mesg, char *buf, struct svc_export *exp) { return 0; }
499 #endif
500 
501 static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
502 {
503 	/* client path expiry [flags anonuid anongid fsid] */
504 	char *buf;
505 	int len;
506 	int err;
507 	struct auth_domain *dom = NULL;
508 	struct nameidata nd;
509 	struct svc_export exp, *expp;
510 	int an_int;
511 
512 	nd.dentry = NULL;
513 	exp.ex_path = NULL;
514 
515 	/* fs locations */
516 	exp.ex_fslocs.locations = NULL;
517 	exp.ex_fslocs.locations_count = 0;
518 	exp.ex_fslocs.migrated = 0;
519 
520 	exp.ex_uuid = NULL;
521 
522 	/* secinfo */
523 	exp.ex_nflavors = 0;
524 
525 	if (mesg[mlen-1] != '\n')
526 		return -EINVAL;
527 	mesg[mlen-1] = 0;
528 
529 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
530 	err = -ENOMEM;
531 	if (!buf) goto out;
532 
533 	/* client */
534 	len = qword_get(&mesg, buf, PAGE_SIZE);
535 	err = -EINVAL;
536 	if (len <= 0) goto out;
537 
538 	err = -ENOENT;
539 	dom = auth_domain_find(buf);
540 	if (!dom)
541 		goto out;
542 
543 	/* path */
544 	err = -EINVAL;
545 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
546 		goto out;
547 	err = path_lookup(buf, 0, &nd);
548 	if (err) goto out_no_path;
549 
550 	exp.h.flags = 0;
551 	exp.ex_client = dom;
552 	exp.ex_mnt = nd.mnt;
553 	exp.ex_dentry = nd.dentry;
554 	exp.ex_path = kstrdup(buf, GFP_KERNEL);
555 	err = -ENOMEM;
556 	if (!exp.ex_path)
557 		goto out;
558 
559 	/* expiry */
560 	err = -EINVAL;
561 	exp.h.expiry_time = get_expiry(&mesg);
562 	if (exp.h.expiry_time == 0)
563 		goto out;
564 
565 	/* flags */
566 	err = get_int(&mesg, &an_int);
567 	if (err == -ENOENT)
568 		set_bit(CACHE_NEGATIVE, &exp.h.flags);
569 	else {
570 		if (err || an_int < 0) goto out;
571 		exp.ex_flags= an_int;
572 
573 		/* anon uid */
574 		err = get_int(&mesg, &an_int);
575 		if (err) goto out;
576 		exp.ex_anon_uid= an_int;
577 
578 		/* anon gid */
579 		err = get_int(&mesg, &an_int);
580 		if (err) goto out;
581 		exp.ex_anon_gid= an_int;
582 
583 		/* fsid */
584 		err = get_int(&mesg, &an_int);
585 		if (err) goto out;
586 		exp.ex_fsid = an_int;
587 
588 		while ((len = qword_get(&mesg, buf, PAGE_SIZE)) > 0) {
589 			if (strcmp(buf, "fsloc") == 0)
590 				err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
591 			else if (strcmp(buf, "uuid") == 0) {
592 				/* expect a 16 byte uuid encoded as \xXXXX... */
593 				len = qword_get(&mesg, buf, PAGE_SIZE);
594 				if (len != 16)
595 					err  = -EINVAL;
596 				else {
597 					exp.ex_uuid =
598 						kmemdup(buf, 16, GFP_KERNEL);
599 					if (exp.ex_uuid == NULL)
600 						err = -ENOMEM;
601 				}
602 			} else if (strcmp(buf, "secinfo") == 0)
603 				err = secinfo_parse(&mesg, buf, &exp);
604 			else
605 				/* quietly ignore unknown words and anything
606 				 * following. Newer user-space can try to set
607 				 * new values, then see what the result was.
608 				 */
609 				break;
610 			if (err)
611 				goto out;
612 		}
613 
614 		err = check_export(nd.dentry->d_inode, exp.ex_flags,
615 				   exp.ex_uuid);
616 		if (err) goto out;
617 	}
618 
619 	expp = svc_export_lookup(&exp);
620 	if (expp)
621 		expp = svc_export_update(&exp, expp);
622 	else
623 		err = -ENOMEM;
624 	cache_flush();
625 	if (expp == NULL)
626 		err = -ENOMEM;
627 	else
628 		exp_put(expp);
629  out:
630 	nfsd4_fslocs_free(&exp.ex_fslocs);
631 	kfree(exp.ex_uuid);
632  	kfree(exp.ex_path);
633 	if (nd.dentry)
634 		path_release(&nd);
635  out_no_path:
636 	if (dom)
637 		auth_domain_put(dom);
638 	kfree(buf);
639 	return err;
640 }
641 
642 static void exp_flags(struct seq_file *m, int flag, int fsid,
643 		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fslocs);
644 
645 static int svc_export_show(struct seq_file *m,
646 			   struct cache_detail *cd,
647 			   struct cache_head *h)
648 {
649 	struct svc_export *exp ;
650 
651 	if (h ==NULL) {
652 		seq_puts(m, "#path domain(flags)\n");
653 		return 0;
654 	}
655 	exp = container_of(h, struct svc_export, h);
656 	seq_path(m, exp->ex_mnt, exp->ex_dentry, " \t\n\\");
657 	seq_putc(m, '\t');
658 	seq_escape(m, exp->ex_client->name, " \t\n\\");
659 	seq_putc(m, '(');
660 	if (test_bit(CACHE_VALID, &h->flags) &&
661 	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
662 		exp_flags(m, exp->ex_flags, exp->ex_fsid,
663 			  exp->ex_anon_uid, exp->ex_anon_gid, &exp->ex_fslocs);
664 		if (exp->ex_uuid) {
665 			int i;
666 			seq_puts(m, ",uuid=");
667 			for (i=0; i<16; i++) {
668 				if ((i&3) == 0 && i)
669 					seq_putc(m, ':');
670 				seq_printf(m, "%02x", exp->ex_uuid[i]);
671 			}
672 		}
673 	}
674 	seq_puts(m, ")\n");
675 	return 0;
676 }
677 static int svc_export_match(struct cache_head *a, struct cache_head *b)
678 {
679 	struct svc_export *orig = container_of(a, struct svc_export, h);
680 	struct svc_export *new = container_of(b, struct svc_export, h);
681 	return orig->ex_client == new->ex_client &&
682 		orig->ex_dentry == new->ex_dentry &&
683 		orig->ex_mnt == new->ex_mnt;
684 }
685 
686 static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
687 {
688 	struct svc_export *new = container_of(cnew, struct svc_export, h);
689 	struct svc_export *item = container_of(citem, struct svc_export, h);
690 
691 	kref_get(&item->ex_client->ref);
692 	new->ex_client = item->ex_client;
693 	new->ex_dentry = dget(item->ex_dentry);
694 	new->ex_mnt = mntget(item->ex_mnt);
695 	new->ex_path = NULL;
696 	new->ex_fslocs.locations = NULL;
697 	new->ex_fslocs.locations_count = 0;
698 	new->ex_fslocs.migrated = 0;
699 }
700 
701 static void export_update(struct cache_head *cnew, struct cache_head *citem)
702 {
703 	struct svc_export *new = container_of(cnew, struct svc_export, h);
704 	struct svc_export *item = container_of(citem, struct svc_export, h);
705 	int i;
706 
707 	new->ex_flags = item->ex_flags;
708 	new->ex_anon_uid = item->ex_anon_uid;
709 	new->ex_anon_gid = item->ex_anon_gid;
710 	new->ex_fsid = item->ex_fsid;
711 	new->ex_uuid = item->ex_uuid;
712 	item->ex_uuid = NULL;
713 	new->ex_path = item->ex_path;
714 	item->ex_path = NULL;
715 	new->ex_fslocs.locations = item->ex_fslocs.locations;
716 	item->ex_fslocs.locations = NULL;
717 	new->ex_fslocs.locations_count = item->ex_fslocs.locations_count;
718 	item->ex_fslocs.locations_count = 0;
719 	new->ex_fslocs.migrated = item->ex_fslocs.migrated;
720 	item->ex_fslocs.migrated = 0;
721 	new->ex_nflavors = item->ex_nflavors;
722 	for (i = 0; i < MAX_SECINFO_LIST; i++) {
723 		new->ex_flavors[i] = item->ex_flavors[i];
724 	}
725 }
726 
727 static struct cache_head *svc_export_alloc(void)
728 {
729 	struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL);
730 	if (i)
731 		return &i->h;
732 	else
733 		return NULL;
734 }
735 
736 struct cache_detail svc_export_cache = {
737 	.owner		= THIS_MODULE,
738 	.hash_size	= EXPORT_HASHMAX,
739 	.hash_table	= export_table,
740 	.name		= "nfsd.export",
741 	.cache_put	= svc_export_put,
742 	.cache_request	= svc_export_request,
743 	.cache_parse	= svc_export_parse,
744 	.cache_show	= svc_export_show,
745 	.match		= svc_export_match,
746 	.init		= svc_export_init,
747 	.update		= export_update,
748 	.alloc		= svc_export_alloc,
749 };
750 
751 static struct svc_export *
752 svc_export_lookup(struct svc_export *exp)
753 {
754 	struct cache_head *ch;
755 	int hash;
756 	hash = hash_ptr(exp->ex_client, EXPORT_HASHBITS);
757 	hash ^= hash_ptr(exp->ex_dentry, EXPORT_HASHBITS);
758 	hash ^= hash_ptr(exp->ex_mnt, EXPORT_HASHBITS);
759 
760 	ch = sunrpc_cache_lookup(&svc_export_cache, &exp->h,
761 				 hash);
762 	if (ch)
763 		return container_of(ch, struct svc_export, h);
764 	else
765 		return NULL;
766 }
767 
768 static struct svc_export *
769 svc_export_update(struct svc_export *new, struct svc_export *old)
770 {
771 	struct cache_head *ch;
772 	int hash;
773 	hash = hash_ptr(old->ex_client, EXPORT_HASHBITS);
774 	hash ^= hash_ptr(old->ex_dentry, EXPORT_HASHBITS);
775 	hash ^= hash_ptr(old->ex_mnt, EXPORT_HASHBITS);
776 
777 	ch = sunrpc_cache_update(&svc_export_cache, &new->h,
778 				 &old->h,
779 				 hash);
780 	if (ch)
781 		return container_of(ch, struct svc_export, h);
782 	else
783 		return NULL;
784 }
785 
786 
787 static struct svc_expkey *
788 exp_find_key(svc_client *clp, int fsid_type, u32 *fsidv, struct cache_req *reqp)
789 {
790 	struct svc_expkey key, *ek;
791 	int err;
792 
793 	if (!clp)
794 		return ERR_PTR(-ENOENT);
795 
796 	key.ek_client = clp;
797 	key.ek_fsidtype = fsid_type;
798 	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
799 
800 	ek = svc_expkey_lookup(&key);
801 	if (ek == NULL)
802 		return ERR_PTR(-ENOMEM);
803 	err = cache_check(&svc_expkey_cache, &ek->h, reqp);
804 	if (err)
805 		return ERR_PTR(err);
806 	return ek;
807 }
808 
809 static int exp_set_key(svc_client *clp, int fsid_type, u32 *fsidv,
810 		       struct svc_export *exp)
811 {
812 	struct svc_expkey key, *ek;
813 
814 	key.ek_client = clp;
815 	key.ek_fsidtype = fsid_type;
816 	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
817 	key.ek_mnt = exp->ex_mnt;
818 	key.ek_dentry = exp->ex_dentry;
819 	key.h.expiry_time = NEVER;
820 	key.h.flags = 0;
821 
822 	ek = svc_expkey_lookup(&key);
823 	if (ek)
824 		ek = svc_expkey_update(&key,ek);
825 	if (ek) {
826 		cache_put(&ek->h, &svc_expkey_cache);
827 		return 0;
828 	}
829 	return -ENOMEM;
830 }
831 
832 /*
833  * Find the client's export entry matching xdev/xino.
834  */
835 static inline struct svc_expkey *
836 exp_get_key(svc_client *clp, dev_t dev, ino_t ino)
837 {
838 	u32 fsidv[3];
839 
840 	if (old_valid_dev(dev)) {
841 		mk_fsid(FSID_DEV, fsidv, dev, ino, 0, NULL);
842 		return exp_find_key(clp, FSID_DEV, fsidv, NULL);
843 	}
844 	mk_fsid(FSID_ENCODE_DEV, fsidv, dev, ino, 0, NULL);
845 	return exp_find_key(clp, FSID_ENCODE_DEV, fsidv, NULL);
846 }
847 
848 /*
849  * Find the client's export entry matching fsid
850  */
851 static inline struct svc_expkey *
852 exp_get_fsid_key(svc_client *clp, int fsid)
853 {
854 	u32 fsidv[2];
855 
856 	mk_fsid(FSID_NUM, fsidv, 0, 0, fsid, NULL);
857 
858 	return exp_find_key(clp, FSID_NUM, fsidv, NULL);
859 }
860 
861 svc_export *
862 exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
863 		struct cache_req *reqp)
864 {
865 	struct svc_export *exp, key;
866 	int err;
867 
868 	if (!clp)
869 		return ERR_PTR(-ENOENT);
870 
871 	key.ex_client = clp;
872 	key.ex_mnt = mnt;
873 	key.ex_dentry = dentry;
874 
875 	exp = svc_export_lookup(&key);
876 	if (exp == NULL)
877 		return ERR_PTR(-ENOMEM);
878 	err = cache_check(&svc_export_cache, &exp->h, reqp);
879 	if (err)
880 		return ERR_PTR(err);
881 	return exp;
882 }
883 
884 /*
885  * Find the export entry for a given dentry.
886  */
887 struct svc_export *
888 exp_parent(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
889 	   struct cache_req *reqp)
890 {
891 	svc_export *exp;
892 
893 	dget(dentry);
894 	exp = exp_get_by_name(clp, mnt, dentry, reqp);
895 
896 	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(dentry)) {
897 		struct dentry *parent;
898 
899 		parent = dget_parent(dentry);
900 		dput(dentry);
901 		dentry = parent;
902 		exp = exp_get_by_name(clp, mnt, dentry, reqp);
903 	}
904 	dput(dentry);
905 	return exp;
906 }
907 
908 /*
909  * Hashtable locking. Write locks are placed only by user processes
910  * wanting to modify export information.
911  * Write locking only done in this file.  Read locking
912  * needed externally.
913  */
914 
915 static DECLARE_RWSEM(hash_sem);
916 
917 void
918 exp_readlock(void)
919 {
920 	down_read(&hash_sem);
921 }
922 
923 static inline void
924 exp_writelock(void)
925 {
926 	down_write(&hash_sem);
927 }
928 
929 void
930 exp_readunlock(void)
931 {
932 	up_read(&hash_sem);
933 }
934 
935 static inline void
936 exp_writeunlock(void)
937 {
938 	up_write(&hash_sem);
939 }
940 
941 static void exp_fsid_unhash(struct svc_export *exp)
942 {
943 	struct svc_expkey *ek;
944 
945 	if ((exp->ex_flags & NFSEXP_FSID) == 0)
946 		return;
947 
948 	ek = exp_get_fsid_key(exp->ex_client, exp->ex_fsid);
949 	if (!IS_ERR(ek)) {
950 		ek->h.expiry_time = get_seconds()-1;
951 		cache_put(&ek->h, &svc_expkey_cache);
952 	}
953 	svc_expkey_cache.nextcheck = get_seconds();
954 }
955 
956 static int exp_fsid_hash(svc_client *clp, struct svc_export *exp)
957 {
958 	u32 fsid[2];
959 
960 	if ((exp->ex_flags & NFSEXP_FSID) == 0)
961 		return 0;
962 
963 	mk_fsid(FSID_NUM, fsid, 0, 0, exp->ex_fsid, NULL);
964 	return exp_set_key(clp, FSID_NUM, fsid, exp);
965 }
966 
967 static int exp_hash(struct auth_domain *clp, struct svc_export *exp)
968 {
969 	u32 fsid[2];
970 	struct inode *inode = exp->ex_dentry->d_inode;
971 	dev_t dev = inode->i_sb->s_dev;
972 
973 	if (old_valid_dev(dev)) {
974 		mk_fsid(FSID_DEV, fsid, dev, inode->i_ino, 0, NULL);
975 		return exp_set_key(clp, FSID_DEV, fsid, exp);
976 	}
977 	mk_fsid(FSID_ENCODE_DEV, fsid, dev, inode->i_ino, 0, NULL);
978 	return exp_set_key(clp, FSID_ENCODE_DEV, fsid, exp);
979 }
980 
981 static void exp_unhash(struct svc_export *exp)
982 {
983 	struct svc_expkey *ek;
984 	struct inode *inode = exp->ex_dentry->d_inode;
985 
986 	ek = exp_get_key(exp->ex_client, inode->i_sb->s_dev, inode->i_ino);
987 	if (!IS_ERR(ek)) {
988 		ek->h.expiry_time = get_seconds()-1;
989 		cache_put(&ek->h, &svc_expkey_cache);
990 	}
991 	svc_expkey_cache.nextcheck = get_seconds();
992 }
993 
994 /*
995  * Export a file system.
996  */
997 int
998 exp_export(struct nfsctl_export *nxp)
999 {
1000 	svc_client	*clp;
1001 	struct svc_export	*exp = NULL;
1002 	struct svc_export	new;
1003 	struct svc_expkey	*fsid_key = NULL;
1004 	struct nameidata nd;
1005 	int		err;
1006 
1007 	/* Consistency check */
1008 	err = -EINVAL;
1009 	if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
1010 	    !exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
1011 		goto out;
1012 
1013 	dprintk("exp_export called for %s:%s (%x/%ld fl %x).\n",
1014 			nxp->ex_client, nxp->ex_path,
1015 			(unsigned)nxp->ex_dev, (long)nxp->ex_ino,
1016 			nxp->ex_flags);
1017 
1018 	/* Try to lock the export table for update */
1019 	exp_writelock();
1020 
1021 	/* Look up client info */
1022 	if (!(clp = auth_domain_find(nxp->ex_client)))
1023 		goto out_unlock;
1024 
1025 
1026 	/* Look up the dentry */
1027 	err = path_lookup(nxp->ex_path, 0, &nd);
1028 	if (err)
1029 		goto out_unlock;
1030 	err = -EINVAL;
1031 
1032 	exp = exp_get_by_name(clp, nd.mnt, nd.dentry, NULL);
1033 
1034 	memset(&new, 0, sizeof(new));
1035 
1036 	/* must make sure there won't be an ex_fsid clash */
1037 	if ((nxp->ex_flags & NFSEXP_FSID) &&
1038 	    (!IS_ERR(fsid_key = exp_get_fsid_key(clp, nxp->ex_dev))) &&
1039 	    fsid_key->ek_mnt &&
1040 	    (fsid_key->ek_mnt != nd.mnt || fsid_key->ek_dentry != nd.dentry) )
1041 		goto finish;
1042 
1043 	if (!IS_ERR(exp)) {
1044 		/* just a flags/id/fsid update */
1045 
1046 		exp_fsid_unhash(exp);
1047 		exp->ex_flags    = nxp->ex_flags;
1048 		exp->ex_anon_uid = nxp->ex_anon_uid;
1049 		exp->ex_anon_gid = nxp->ex_anon_gid;
1050 		exp->ex_fsid     = nxp->ex_dev;
1051 
1052 		err = exp_fsid_hash(clp, exp);
1053 		goto finish;
1054 	}
1055 
1056 	err = check_export(nd.dentry->d_inode, nxp->ex_flags, NULL);
1057 	if (err) goto finish;
1058 
1059 	err = -ENOMEM;
1060 
1061 	dprintk("nfsd: creating export entry %p for client %p\n", exp, clp);
1062 
1063 	new.h.expiry_time = NEVER;
1064 	new.h.flags = 0;
1065 	new.ex_path = kstrdup(nxp->ex_path, GFP_KERNEL);
1066 	if (!new.ex_path)
1067 		goto finish;
1068 	new.ex_client = clp;
1069 	new.ex_mnt = nd.mnt;
1070 	new.ex_dentry = nd.dentry;
1071 	new.ex_flags = nxp->ex_flags;
1072 	new.ex_anon_uid = nxp->ex_anon_uid;
1073 	new.ex_anon_gid = nxp->ex_anon_gid;
1074 	new.ex_fsid = nxp->ex_dev;
1075 
1076 	exp = svc_export_lookup(&new);
1077 	if (exp)
1078 		exp = svc_export_update(&new, exp);
1079 
1080 	if (!exp)
1081 		goto finish;
1082 
1083 	if (exp_hash(clp, exp) ||
1084 	    exp_fsid_hash(clp, exp)) {
1085 		/* failed to create at least one index */
1086 		exp_do_unexport(exp);
1087 		cache_flush();
1088 	} else
1089 		err = 0;
1090 finish:
1091 	if (new.ex_path)
1092 		kfree(new.ex_path);
1093 	if (exp)
1094 		exp_put(exp);
1095 	if (fsid_key && !IS_ERR(fsid_key))
1096 		cache_put(&fsid_key->h, &svc_expkey_cache);
1097 	if (clp)
1098 		auth_domain_put(clp);
1099 	path_release(&nd);
1100 out_unlock:
1101 	exp_writeunlock();
1102 out:
1103 	return err;
1104 }
1105 
1106 /*
1107  * Unexport a file system. The export entry has already
1108  * been removed from the client's list of exported fs's.
1109  */
1110 static void
1111 exp_do_unexport(svc_export *unexp)
1112 {
1113 	unexp->h.expiry_time = get_seconds()-1;
1114 	svc_export_cache.nextcheck = get_seconds();
1115 	exp_unhash(unexp);
1116 	exp_fsid_unhash(unexp);
1117 }
1118 
1119 
1120 /*
1121  * unexport syscall.
1122  */
1123 int
1124 exp_unexport(struct nfsctl_export *nxp)
1125 {
1126 	struct auth_domain *dom;
1127 	svc_export *exp;
1128 	struct nameidata nd;
1129 	int		err;
1130 
1131 	/* Consistency check */
1132 	if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
1133 	    !exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
1134 		return -EINVAL;
1135 
1136 	exp_writelock();
1137 
1138 	err = -EINVAL;
1139 	dom = auth_domain_find(nxp->ex_client);
1140 	if (!dom) {
1141 		dprintk("nfsd: unexport couldn't find %s\n", nxp->ex_client);
1142 		goto out_unlock;
1143 	}
1144 
1145 	err = path_lookup(nxp->ex_path, 0, &nd);
1146 	if (err)
1147 		goto out_domain;
1148 
1149 	err = -EINVAL;
1150 	exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);
1151 	path_release(&nd);
1152 	if (IS_ERR(exp))
1153 		goto out_domain;
1154 
1155 	exp_do_unexport(exp);
1156 	exp_put(exp);
1157 	err = 0;
1158 
1159 out_domain:
1160 	auth_domain_put(dom);
1161 	cache_flush();
1162 out_unlock:
1163 	exp_writeunlock();
1164 	return err;
1165 }
1166 
1167 /*
1168  * Obtain the root fh on behalf of a client.
1169  * This could be done in user space, but I feel that it adds some safety
1170  * since its harder to fool a kernel module than a user space program.
1171  */
1172 int
1173 exp_rootfh(svc_client *clp, char *path, struct knfsd_fh *f, int maxsize)
1174 {
1175 	struct svc_export	*exp;
1176 	struct nameidata	nd;
1177 	struct inode		*inode;
1178 	struct svc_fh		fh;
1179 	int			err;
1180 
1181 	err = -EPERM;
1182 	/* NB: we probably ought to check that it's NUL-terminated */
1183 	if (path_lookup(path, 0, &nd)) {
1184 		printk("nfsd: exp_rootfh path not found %s", path);
1185 		return err;
1186 	}
1187 	inode = nd.dentry->d_inode;
1188 
1189 	dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)\n",
1190 		 path, nd.dentry, clp->name,
1191 		 inode->i_sb->s_id, inode->i_ino);
1192 	exp = exp_parent(clp, nd.mnt, nd.dentry, NULL);
1193 	if (IS_ERR(exp)) {
1194 		err = PTR_ERR(exp);
1195 		goto out;
1196 	}
1197 
1198 	/*
1199 	 * fh must be initialized before calling fh_compose
1200 	 */
1201 	fh_init(&fh, maxsize);
1202 	if (fh_compose(&fh, exp, nd.dentry, NULL))
1203 		err = -EINVAL;
1204 	else
1205 		err = 0;
1206 	memcpy(f, &fh.fh_handle, sizeof(struct knfsd_fh));
1207 	fh_put(&fh);
1208 	exp_put(exp);
1209 out:
1210 	path_release(&nd);
1211 	return err;
1212 }
1213 
1214 struct svc_export *
1215 exp_find(struct auth_domain *clp, int fsid_type, u32 *fsidv,
1216 	 struct cache_req *reqp)
1217 {
1218 	struct svc_export *exp;
1219 	struct svc_expkey *ek = exp_find_key(clp, fsid_type, fsidv, reqp);
1220 	if (IS_ERR(ek))
1221 		return ERR_PTR(PTR_ERR(ek));
1222 
1223 	exp = exp_get_by_name(clp, ek->ek_mnt, ek->ek_dentry, reqp);
1224 	cache_put(&ek->h, &svc_expkey_cache);
1225 
1226 	if (IS_ERR(exp))
1227 		return ERR_PTR(PTR_ERR(exp));
1228 	return exp;
1229 }
1230 
1231 __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
1232 {
1233 	struct exp_flavor_info *f;
1234 	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
1235 
1236 	/* legacy gss-only clients are always OK: */
1237 	if (exp->ex_client == rqstp->rq_gssclient)
1238 		return 0;
1239 	/* ip-address based client; check sec= export option: */
1240 	for (f = exp->ex_flavors; f < end; f++) {
1241 		if (f->pseudoflavor == rqstp->rq_flavor)
1242 			return 0;
1243 	}
1244 	/* defaults in absence of sec= options: */
1245 	if (exp->ex_nflavors == 0) {
1246 		if (rqstp->rq_flavor == RPC_AUTH_NULL ||
1247 		    rqstp->rq_flavor == RPC_AUTH_UNIX)
1248 			return 0;
1249 	}
1250 	return nfserr_wrongsec;
1251 }
1252 
1253 /*
1254  * Uses rq_client and rq_gssclient to find an export; uses rq_client (an
1255  * auth_unix client) if it's available and has secinfo information;
1256  * otherwise, will try to use rq_gssclient.
1257  *
1258  * Called from functions that handle requests; functions that do work on
1259  * behalf of mountd are passed a single client name to use, and should
1260  * use exp_get_by_name() or exp_find().
1261  */
1262 struct svc_export *
1263 rqst_exp_get_by_name(struct svc_rqst *rqstp, struct vfsmount *mnt,
1264 		struct dentry *dentry)
1265 {
1266 	struct svc_export *gssexp, *exp = NULL;
1267 
1268 	if (rqstp->rq_client == NULL)
1269 		goto gss;
1270 
1271 	/* First try the auth_unix client: */
1272 	exp = exp_get_by_name(rqstp->rq_client, mnt, dentry,
1273 						&rqstp->rq_chandle);
1274 	if (PTR_ERR(exp) == -ENOENT)
1275 		goto gss;
1276 	if (IS_ERR(exp))
1277 		return exp;
1278 	/* If it has secinfo, assume there are no gss/... clients */
1279 	if (exp->ex_nflavors > 0)
1280 		return exp;
1281 gss:
1282 	/* Otherwise, try falling back on gss client */
1283 	if (rqstp->rq_gssclient == NULL)
1284 		return exp;
1285 	gssexp = exp_get_by_name(rqstp->rq_gssclient, mnt, dentry,
1286 						&rqstp->rq_chandle);
1287 	if (PTR_ERR(gssexp) == -ENOENT)
1288 		return exp;
1289 	if (exp && !IS_ERR(exp))
1290 		exp_put(exp);
1291 	return gssexp;
1292 }
1293 
1294 struct svc_export *
1295 rqst_exp_find(struct svc_rqst *rqstp, int fsid_type, u32 *fsidv)
1296 {
1297 	struct svc_export *gssexp, *exp = NULL;
1298 
1299 	if (rqstp->rq_client == NULL)
1300 		goto gss;
1301 
1302 	/* First try the auth_unix client: */
1303 	exp = exp_find(rqstp->rq_client, fsid_type, fsidv, &rqstp->rq_chandle);
1304 	if (PTR_ERR(exp) == -ENOENT)
1305 		goto gss;
1306 	if (IS_ERR(exp))
1307 		return exp;
1308 	/* If it has secinfo, assume there are no gss/... clients */
1309 	if (exp->ex_nflavors > 0)
1310 		return exp;
1311 gss:
1312 	/* Otherwise, try falling back on gss client */
1313 	if (rqstp->rq_gssclient == NULL)
1314 		return exp;
1315 	gssexp = exp_find(rqstp->rq_gssclient, fsid_type, fsidv,
1316 						&rqstp->rq_chandle);
1317 	if (PTR_ERR(gssexp) == -ENOENT)
1318 		return exp;
1319 	if (exp && !IS_ERR(exp))
1320 		exp_put(exp);
1321 	return gssexp;
1322 }
1323 
1324 struct svc_export *
1325 rqst_exp_parent(struct svc_rqst *rqstp, struct vfsmount *mnt,
1326 		struct dentry *dentry)
1327 {
1328 	struct svc_export *exp;
1329 
1330 	dget(dentry);
1331 	exp = rqst_exp_get_by_name(rqstp, mnt, dentry);
1332 
1333 	while (PTR_ERR(exp) == -ENOENT && !IS_ROOT(dentry)) {
1334 		struct dentry *parent;
1335 
1336 		parent = dget_parent(dentry);
1337 		dput(dentry);
1338 		dentry = parent;
1339 		exp = rqst_exp_get_by_name(rqstp, mnt, dentry);
1340 	}
1341 	dput(dentry);
1342 	return exp;
1343 }
1344 
1345 /*
1346  * Called when we need the filehandle for the root of the pseudofs,
1347  * for a given NFSv4 client.   The root is defined to be the
1348  * export point with fsid==0
1349  */
1350 __be32
1351 exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
1352 {
1353 	struct svc_export *exp;
1354 	__be32 rv;
1355 	u32 fsidv[2];
1356 
1357 	mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
1358 
1359 	exp = rqst_exp_find(rqstp, FSID_NUM, fsidv);
1360 	if (PTR_ERR(exp) == -ENOENT)
1361 		return nfserr_perm;
1362 	if (IS_ERR(exp))
1363 		return nfserrno(PTR_ERR(exp));
1364 	rv = fh_compose(fhp, exp, exp->ex_dentry, NULL);
1365 	if (rv)
1366 		goto out;
1367 	rv = check_nfsd_access(exp, rqstp);
1368 out:
1369 	exp_put(exp);
1370 	return rv;
1371 }
1372 
1373 /* Iterator */
1374 
1375 static void *e_start(struct seq_file *m, loff_t *pos)
1376 	__acquires(svc_export_cache.hash_lock)
1377 {
1378 	loff_t n = *pos;
1379 	unsigned hash, export;
1380 	struct cache_head *ch;
1381 
1382 	exp_readlock();
1383 	read_lock(&svc_export_cache.hash_lock);
1384 	if (!n--)
1385 		return SEQ_START_TOKEN;
1386 	hash = n >> 32;
1387 	export = n & ((1LL<<32) - 1);
1388 
1389 
1390 	for (ch=export_table[hash]; ch; ch=ch->next)
1391 		if (!export--)
1392 			return ch;
1393 	n &= ~((1LL<<32) - 1);
1394 	do {
1395 		hash++;
1396 		n += 1LL<<32;
1397 	} while(hash < EXPORT_HASHMAX && export_table[hash]==NULL);
1398 	if (hash >= EXPORT_HASHMAX)
1399 		return NULL;
1400 	*pos = n+1;
1401 	return export_table[hash];
1402 }
1403 
1404 static void *e_next(struct seq_file *m, void *p, loff_t *pos)
1405 {
1406 	struct cache_head *ch = p;
1407 	int hash = (*pos >> 32);
1408 
1409 	if (p == SEQ_START_TOKEN)
1410 		hash = 0;
1411 	else if (ch->next == NULL) {
1412 		hash++;
1413 		*pos += 1LL<<32;
1414 	} else {
1415 		++*pos;
1416 		return ch->next;
1417 	}
1418 	*pos &= ~((1LL<<32) - 1);
1419 	while (hash < EXPORT_HASHMAX && export_table[hash] == NULL) {
1420 		hash++;
1421 		*pos += 1LL<<32;
1422 	}
1423 	if (hash >= EXPORT_HASHMAX)
1424 		return NULL;
1425 	++*pos;
1426 	return export_table[hash];
1427 }
1428 
1429 static void e_stop(struct seq_file *m, void *p)
1430 	__releases(svc_export_cache.hash_lock)
1431 {
1432 	read_unlock(&svc_export_cache.hash_lock);
1433 	exp_readunlock();
1434 }
1435 
1436 static struct flags {
1437 	int flag;
1438 	char *name[2];
1439 } expflags[] = {
1440 	{ NFSEXP_READONLY, {"ro", "rw"}},
1441 	{ NFSEXP_INSECURE_PORT, {"insecure", ""}},
1442 	{ NFSEXP_ROOTSQUASH, {"root_squash", "no_root_squash"}},
1443 	{ NFSEXP_ALLSQUASH, {"all_squash", ""}},
1444 	{ NFSEXP_ASYNC, {"async", "sync"}},
1445 	{ NFSEXP_GATHERED_WRITES, {"wdelay", "no_wdelay"}},
1446 	{ NFSEXP_NOHIDE, {"nohide", ""}},
1447 	{ NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
1448 	{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
1449 	{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
1450 #ifdef MSNFS
1451 	{ NFSEXP_MSNFS, {"msnfs", ""}},
1452 #endif
1453 	{ 0, {"", ""}}
1454 };
1455 
1456 static void exp_flags(struct seq_file *m, int flag, int fsid,
1457 		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fsloc)
1458 {
1459 	int first = 0;
1460 	struct flags *flg;
1461 
1462 	for (flg = expflags; flg->flag; flg++) {
1463 		int state = (flg->flag & flag)?0:1;
1464 		if (*flg->name[state])
1465 			seq_printf(m, "%s%s", first++?",":"", flg->name[state]);
1466 	}
1467 	if (flag & NFSEXP_FSID)
1468 		seq_printf(m, "%sfsid=%d", first++?",":"", fsid);
1469 	if (anonu != (uid_t)-2 && anonu != (0x10000-2))
1470 		seq_printf(m, "%sanonuid=%d", first++?",":"", anonu);
1471 	if (anong != (gid_t)-2 && anong != (0x10000-2))
1472 		seq_printf(m, "%sanongid=%d", first++?",":"", anong);
1473 	if (fsloc && fsloc->locations_count > 0) {
1474 		char *loctype = (fsloc->migrated) ? "refer" : "replicas";
1475 		int i;
1476 
1477 		seq_printf(m, "%s%s=", first++?",":"", loctype);
1478 		seq_escape(m, fsloc->locations[0].path, ",;@ \t\n\\");
1479 		seq_putc(m, '@');
1480 		seq_escape(m, fsloc->locations[0].hosts, ",;@ \t\n\\");
1481 		for (i = 1; i < fsloc->locations_count; i++) {
1482 			seq_putc(m, ';');
1483 			seq_escape(m, fsloc->locations[i].path, ",;@ \t\n\\");
1484 			seq_putc(m, '@');
1485 			seq_escape(m, fsloc->locations[i].hosts, ",;@ \t\n\\");
1486 		}
1487 	}
1488 }
1489 
1490 static int e_show(struct seq_file *m, void *p)
1491 {
1492 	struct cache_head *cp = p;
1493 	struct svc_export *exp = container_of(cp, struct svc_export, h);
1494 
1495 	if (p == SEQ_START_TOKEN) {
1496 		seq_puts(m, "# Version 1.1\n");
1497 		seq_puts(m, "# Path Client(Flags) # IPs\n");
1498 		return 0;
1499 	}
1500 
1501 	cache_get(&exp->h);
1502 	if (cache_check(&svc_export_cache, &exp->h, NULL))
1503 		return 0;
1504 	cache_put(&exp->h, &svc_export_cache);
1505 	return svc_export_show(m, &svc_export_cache, cp);
1506 }
1507 
1508 struct seq_operations nfs_exports_op = {
1509 	.start	= e_start,
1510 	.next	= e_next,
1511 	.stop	= e_stop,
1512 	.show	= e_show,
1513 };
1514 
1515 /*
1516  * Add or modify a client.
1517  * Change requests may involve the list of host addresses. The list of
1518  * exports and possibly existing uid maps are left untouched.
1519  */
1520 int
1521 exp_addclient(struct nfsctl_client *ncp)
1522 {
1523 	struct auth_domain	*dom;
1524 	int			i, err;
1525 
1526 	/* First, consistency check. */
1527 	err = -EINVAL;
1528 	if (! exp_verify_string(ncp->cl_ident, NFSCLNT_IDMAX))
1529 		goto out;
1530 	if (ncp->cl_naddr > NFSCLNT_ADDRMAX)
1531 		goto out;
1532 
1533 	/* Lock the hashtable */
1534 	exp_writelock();
1535 
1536 	dom = unix_domain_find(ncp->cl_ident);
1537 
1538 	err = -ENOMEM;
1539 	if (!dom)
1540 		goto out_unlock;
1541 
1542 	/* Insert client into hashtable. */
1543 	for (i = 0; i < ncp->cl_naddr; i++)
1544 		auth_unix_add_addr(ncp->cl_addrlist[i], dom);
1545 
1546 	auth_unix_forget_old(dom);
1547 	auth_domain_put(dom);
1548 
1549 	err = 0;
1550 
1551 out_unlock:
1552 	exp_writeunlock();
1553 out:
1554 	return err;
1555 }
1556 
1557 /*
1558  * Delete a client given an identifier.
1559  */
1560 int
1561 exp_delclient(struct nfsctl_client *ncp)
1562 {
1563 	int		err;
1564 	struct auth_domain *dom;
1565 
1566 	err = -EINVAL;
1567 	if (!exp_verify_string(ncp->cl_ident, NFSCLNT_IDMAX))
1568 		goto out;
1569 
1570 	/* Lock the hashtable */
1571 	exp_writelock();
1572 
1573 	dom = auth_domain_find(ncp->cl_ident);
1574 	/* just make sure that no addresses work
1575 	 * and that it will expire soon
1576 	 */
1577 	if (dom) {
1578 		err = auth_unix_forget_old(dom);
1579 		auth_domain_put(dom);
1580 	}
1581 
1582 	exp_writeunlock();
1583 out:
1584 	return err;
1585 }
1586 
1587 /*
1588  * Verify that string is non-empty and does not exceed max length.
1589  */
1590 static int
1591 exp_verify_string(char *cp, int max)
1592 {
1593 	int	i;
1594 
1595 	for (i = 0; i < max; i++)
1596 		if (!cp[i])
1597 			return i;
1598 	cp[i] = 0;
1599 	printk(KERN_NOTICE "nfsd: couldn't validate string %s\n", cp);
1600 	return 0;
1601 }
1602 
1603 /*
1604  * Initialize the exports module.
1605  */
1606 void
1607 nfsd_export_init(void)
1608 {
1609 	dprintk("nfsd: initializing export module.\n");
1610 
1611 	cache_register(&svc_export_cache);
1612 	cache_register(&svc_expkey_cache);
1613 
1614 }
1615 
1616 /*
1617  * Flush exports table - called when last nfsd thread is killed
1618  */
1619 void
1620 nfsd_export_flush(void)
1621 {
1622 	exp_writelock();
1623 	cache_purge(&svc_expkey_cache);
1624 	cache_purge(&svc_export_cache);
1625 	exp_writeunlock();
1626 }
1627 
1628 /*
1629  * Shutdown the exports module.
1630  */
1631 void
1632 nfsd_export_shutdown(void)
1633 {
1634 
1635 	dprintk("nfsd: shutting down export module.\n");
1636 
1637 	exp_writelock();
1638 
1639 	if (cache_unregister(&svc_expkey_cache))
1640 		printk(KERN_ERR "nfsd: failed to unregister expkey cache\n");
1641 	if (cache_unregister(&svc_export_cache))
1642 		printk(KERN_ERR "nfsd: failed to unregister export cache\n");
1643 	svcauth_unix_purge();
1644 
1645 	exp_writeunlock();
1646 	dprintk("nfsd: export shutdown complete.\n");
1647 }
1648