xref: /openbmc/linux/fs/nfsd/export.c (revision a569425512253992cc64ebf8b6d00a62f986db3e)
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 
37 #define NFSDDBG_FACILITY	NFSDDBG_EXPORT
38 
39 typedef struct auth_domain	svc_client;
40 typedef struct svc_export	svc_export;
41 
42 static void		exp_do_unexport(svc_export *unexp);
43 static int		exp_verify_string(char *cp, int max);
44 
45 /*
46  * We have two caches.
47  * One maps client+vfsmnt+dentry to export options - the export map
48  * The other maps client+filehandle-fragment to export options. - the expkey map
49  *
50  * The export options are actually stored in the first map, and the
51  * second map contains a reference to the entry in the first map.
52  */
53 
54 #define	EXPKEY_HASHBITS		8
55 #define	EXPKEY_HASHMAX		(1 << EXPKEY_HASHBITS)
56 #define	EXPKEY_HASHMASK		(EXPKEY_HASHMAX -1)
57 static struct cache_head *expkey_table[EXPKEY_HASHMAX];
58 
59 static void expkey_put(struct kref *ref)
60 {
61 	struct svc_expkey *key = container_of(ref, struct svc_expkey, h.ref);
62 
63 	if (test_bit(CACHE_VALID, &key->h.flags) &&
64 	    !test_bit(CACHE_NEGATIVE, &key->h.flags)) {
65 		dput(key->ek_dentry);
66 		mntput(key->ek_mnt);
67 	}
68 	auth_domain_put(key->ek_client);
69 	kfree(key);
70 }
71 
72 static void expkey_request(struct cache_detail *cd,
73 			   struct cache_head *h,
74 			   char **bpp, int *blen)
75 {
76 	/* client fsidtype \xfsid */
77 	struct svc_expkey *ek = container_of(h, struct svc_expkey, h);
78 	char type[5];
79 
80 	qword_add(bpp, blen, ek->ek_client->name);
81 	snprintf(type, 5, "%d", ek->ek_fsidtype);
82 	qword_add(bpp, blen, type);
83 	qword_addhex(bpp, blen, (char*)ek->ek_fsid, key_len(ek->ek_fsidtype));
84 	(*bpp)[-1] = '\n';
85 }
86 
87 static struct svc_expkey *svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old);
88 static struct svc_expkey *svc_expkey_lookup(struct svc_expkey *);
89 static struct cache_detail svc_expkey_cache;
90 
91 static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
92 {
93 	/* client fsidtype fsid [path] */
94 	char *buf;
95 	int len;
96 	struct auth_domain *dom = NULL;
97 	int err;
98 	int fsidtype;
99 	char *ep;
100 	struct svc_expkey key;
101 	struct svc_expkey *ek;
102 
103 	if (mesg[mlen-1] != '\n')
104 		return -EINVAL;
105 	mesg[mlen-1] = 0;
106 
107 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
108 	err = -ENOMEM;
109 	if (!buf) goto out;
110 
111 	err = -EINVAL;
112 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
113 		goto out;
114 
115 	err = -ENOENT;
116 	dom = auth_domain_find(buf);
117 	if (!dom)
118 		goto out;
119 	dprintk("found domain %s\n", buf);
120 
121 	err = -EINVAL;
122 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
123 		goto out;
124 	fsidtype = simple_strtoul(buf, &ep, 10);
125 	if (*ep)
126 		goto out;
127 	dprintk("found fsidtype %d\n", fsidtype);
128 	if (key_len(fsidtype)==0) /* invalid type */
129 		goto out;
130 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
131 		goto out;
132 	dprintk("found fsid length %d\n", len);
133 	if (len != key_len(fsidtype))
134 		goto out;
135 
136 	/* OK, we seem to have a valid key */
137 	key.h.flags = 0;
138 	key.h.expiry_time = get_expiry(&mesg);
139 	if (key.h.expiry_time == 0)
140 		goto out;
141 
142 	key.ek_client = dom;
143 	key.ek_fsidtype = fsidtype;
144 	memcpy(key.ek_fsid, buf, len);
145 
146 	ek = svc_expkey_lookup(&key);
147 	err = -ENOMEM;
148 	if (!ek)
149 		goto out;
150 
151 	/* now we want a pathname, or empty meaning NEGATIVE  */
152 	err = -EINVAL;
153 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) < 0)
154 		goto out;
155 	dprintk("Path seems to be <%s>\n", buf);
156 	err = 0;
157 	if (len == 0) {
158 		set_bit(CACHE_NEGATIVE, &key.h.flags);
159 		ek = svc_expkey_update(&key, ek);
160 		if (ek)
161 			cache_put(&ek->h, &svc_expkey_cache);
162 		else err = -ENOMEM;
163 	} else {
164 		struct nameidata nd;
165 		err = path_lookup(buf, 0, &nd);
166 		if (err)
167 			goto out;
168 
169 		dprintk("Found the path %s\n", buf);
170 		key.ek_mnt = nd.mnt;
171 		key.ek_dentry = nd.dentry;
172 
173 		ek = svc_expkey_update(&key, ek);
174 		if (ek)
175 			cache_put(&ek->h, &svc_expkey_cache);
176 		else
177 			err = -ENOMEM;
178 		path_release(&nd);
179 	}
180 	cache_flush();
181  out:
182 	if (dom)
183 		auth_domain_put(dom);
184 	kfree(buf);
185 	return err;
186 }
187 
188 static int expkey_show(struct seq_file *m,
189 		       struct cache_detail *cd,
190 		       struct cache_head *h)
191 {
192 	struct svc_expkey *ek ;
193 	int i;
194 
195 	if (h ==NULL) {
196 		seq_puts(m, "#domain fsidtype fsid [path]\n");
197 		return 0;
198 	}
199 	ek = container_of(h, struct svc_expkey, h);
200 	seq_printf(m, "%s %d 0x", ek->ek_client->name,
201 		   ek->ek_fsidtype);
202 	for (i=0; i < key_len(ek->ek_fsidtype)/4; i++)
203 		seq_printf(m, "%08x", ek->ek_fsid[i]);
204 	if (test_bit(CACHE_VALID, &h->flags) &&
205 	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
206 		seq_printf(m, " ");
207 		seq_path(m, ek->ek_mnt, ek->ek_dentry, "\\ \t\n");
208 	}
209 	seq_printf(m, "\n");
210 	return 0;
211 }
212 
213 static inline int expkey_match (struct cache_head *a, struct cache_head *b)
214 {
215 	struct svc_expkey *orig = container_of(a, struct svc_expkey, h);
216 	struct svc_expkey *new = container_of(b, struct svc_expkey, h);
217 
218 	if (orig->ek_fsidtype != new->ek_fsidtype ||
219 	    orig->ek_client != new->ek_client ||
220 	    memcmp(orig->ek_fsid, new->ek_fsid, key_len(orig->ek_fsidtype)) != 0)
221 		return 0;
222 	return 1;
223 }
224 
225 static inline void expkey_init(struct cache_head *cnew,
226 				   struct cache_head *citem)
227 {
228 	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
229 	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);
230 
231 	kref_get(&item->ek_client->ref);
232 	new->ek_client = item->ek_client;
233 	new->ek_fsidtype = item->ek_fsidtype;
234 
235 	memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid));
236 }
237 
238 static inline void expkey_update(struct cache_head *cnew,
239 				   struct cache_head *citem)
240 {
241 	struct svc_expkey *new = container_of(cnew, struct svc_expkey, h);
242 	struct svc_expkey *item = container_of(citem, struct svc_expkey, h);
243 
244 	new->ek_mnt = mntget(item->ek_mnt);
245 	new->ek_dentry = dget(item->ek_dentry);
246 }
247 
248 static struct cache_head *expkey_alloc(void)
249 {
250 	struct svc_expkey *i = kmalloc(sizeof(*i), GFP_KERNEL);
251 	if (i)
252 		return &i->h;
253 	else
254 		return NULL;
255 }
256 
257 static struct cache_detail svc_expkey_cache = {
258 	.owner		= THIS_MODULE,
259 	.hash_size	= EXPKEY_HASHMAX,
260 	.hash_table	= expkey_table,
261 	.name		= "nfsd.fh",
262 	.cache_put	= expkey_put,
263 	.cache_request	= expkey_request,
264 	.cache_parse	= expkey_parse,
265 	.cache_show	= expkey_show,
266 	.match		= expkey_match,
267 	.init		= expkey_init,
268 	.update       	= expkey_update,
269 	.alloc		= expkey_alloc,
270 };
271 
272 static struct svc_expkey *
273 svc_expkey_lookup(struct svc_expkey *item)
274 {
275 	struct cache_head *ch;
276 	int hash = item->ek_fsidtype;
277 	char * cp = (char*)item->ek_fsid;
278 	int len = key_len(item->ek_fsidtype);
279 
280 	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
281 	hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
282 	hash &= EXPKEY_HASHMASK;
283 
284 	ch = sunrpc_cache_lookup(&svc_expkey_cache, &item->h,
285 				 hash);
286 	if (ch)
287 		return container_of(ch, struct svc_expkey, h);
288 	else
289 		return NULL;
290 }
291 
292 static struct svc_expkey *
293 svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old)
294 {
295 	struct cache_head *ch;
296 	int hash = new->ek_fsidtype;
297 	char * cp = (char*)new->ek_fsid;
298 	int len = key_len(new->ek_fsidtype);
299 
300 	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
301 	hash ^= hash_ptr(new->ek_client, EXPKEY_HASHBITS);
302 	hash &= EXPKEY_HASHMASK;
303 
304 	ch = sunrpc_cache_update(&svc_expkey_cache, &new->h,
305 				 &old->h, hash);
306 	if (ch)
307 		return container_of(ch, struct svc_expkey, h);
308 	else
309 		return NULL;
310 }
311 
312 
313 #define	EXPORT_HASHBITS		8
314 #define	EXPORT_HASHMAX		(1<< EXPORT_HASHBITS)
315 #define	EXPORT_HASHMASK		(EXPORT_HASHMAX -1)
316 
317 static struct cache_head *export_table[EXPORT_HASHMAX];
318 
319 static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
320 {
321 	int i;
322 
323 	for (i = 0; i < fsloc->locations_count; i++) {
324 		kfree(fsloc->locations[i].path);
325 		kfree(fsloc->locations[i].hosts);
326 	}
327 	kfree(fsloc->locations);
328 }
329 
330 static void svc_export_put(struct kref *ref)
331 {
332 	struct svc_export *exp = container_of(ref, struct svc_export, h.ref);
333 	dput(exp->ex_dentry);
334 	mntput(exp->ex_mnt);
335 	auth_domain_put(exp->ex_client);
336 	kfree(exp->ex_path);
337 	nfsd4_fslocs_free(&exp->ex_fslocs);
338 	kfree(exp);
339 }
340 
341 static void svc_export_request(struct cache_detail *cd,
342 			       struct cache_head *h,
343 			       char **bpp, int *blen)
344 {
345 	/*  client path */
346 	struct svc_export *exp = container_of(h, struct svc_export, h);
347 	char *pth;
348 
349 	qword_add(bpp, blen, exp->ex_client->name);
350 	pth = d_path(exp->ex_dentry, exp->ex_mnt, *bpp, *blen);
351 	if (IS_ERR(pth)) {
352 		/* is this correct? */
353 		(*bpp)[0] = '\n';
354 		return;
355 	}
356 	qword_add(bpp, blen, pth);
357 	(*bpp)[-1] = '\n';
358 }
359 
360 static struct svc_export *svc_export_update(struct svc_export *new,
361 					    struct svc_export *old);
362 static struct svc_export *svc_export_lookup(struct svc_export *);
363 
364 static int check_export(struct inode *inode, int flags, unsigned char *uuid)
365 {
366 
367 	/* We currently export only dirs and regular files.
368 	 * This is what umountd does.
369 	 */
370 	if (!S_ISDIR(inode->i_mode) &&
371 	    !S_ISREG(inode->i_mode))
372 		return -ENOTDIR;
373 
374 	/* There are two requirements on a filesystem to be exportable.
375 	 * 1:  We must be able to identify the filesystem from a number.
376 	 *       either a device number (so FS_REQUIRES_DEV needed)
377 	 *       or an FSID number (so NFSEXP_FSID or ->uuid is needed).
378 	 * 2:  We must be able to find an inode from a filehandle.
379 	 *       This means that s_export_op must be set.
380 	 */
381 	if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
382 	    !(flags & NFSEXP_FSID) &&
383 	    uuid == NULL) {
384 		dprintk("exp_export: export of non-dev fs without fsid\n");
385 		return -EINVAL;
386 	}
387 	if (!inode->i_sb->s_export_op) {
388 		dprintk("exp_export: export of invalid fs type.\n");
389 		return -EINVAL;
390 	}
391 
392 	/* Ok, we can export it */;
393 	if (!inode->i_sb->s_export_op->find_exported_dentry)
394 		inode->i_sb->s_export_op->find_exported_dentry =
395 			find_exported_dentry;
396 	return 0;
397 
398 }
399 
400 #ifdef CONFIG_NFSD_V4
401 
402 static int
403 fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
404 {
405 	int len;
406 	int migrated, i, err;
407 
408 	/* listsize */
409 	err = get_int(mesg, &fsloc->locations_count);
410 	if (err)
411 		return err;
412 	if (fsloc->locations_count > MAX_FS_LOCATIONS)
413 		return -EINVAL;
414 	if (fsloc->locations_count == 0)
415 		return 0;
416 
417 	fsloc->locations = kzalloc(fsloc->locations_count
418 			* sizeof(struct nfsd4_fs_location), GFP_KERNEL);
419 	if (!fsloc->locations)
420 		return -ENOMEM;
421 	for (i=0; i < fsloc->locations_count; i++) {
422 		/* colon separated host list */
423 		err = -EINVAL;
424 		len = qword_get(mesg, buf, PAGE_SIZE);
425 		if (len <= 0)
426 			goto out_free_all;
427 		err = -ENOMEM;
428 		fsloc->locations[i].hosts = kstrdup(buf, GFP_KERNEL);
429 		if (!fsloc->locations[i].hosts)
430 			goto out_free_all;
431 		err = -EINVAL;
432 		/* slash separated path component list */
433 		len = qword_get(mesg, buf, PAGE_SIZE);
434 		if (len <= 0)
435 			goto out_free_all;
436 		err = -ENOMEM;
437 		fsloc->locations[i].path = kstrdup(buf, GFP_KERNEL);
438 		if (!fsloc->locations[i].path)
439 			goto out_free_all;
440 	}
441 	/* migrated */
442 	err = get_int(mesg, &migrated);
443 	if (err)
444 		goto out_free_all;
445 	err = -EINVAL;
446 	if (migrated < 0 || migrated > 1)
447 		goto out_free_all;
448 	fsloc->migrated = migrated;
449 	return 0;
450 out_free_all:
451 	nfsd4_fslocs_free(fsloc);
452 	return err;
453 }
454 
455 #else /* CONFIG_NFSD_V4 */
456 static inline int fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc) { return 0; }
457 #endif
458 
459 static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
460 {
461 	/* client path expiry [flags anonuid anongid fsid] */
462 	char *buf;
463 	int len;
464 	int err;
465 	struct auth_domain *dom = NULL;
466 	struct nameidata nd;
467 	struct svc_export exp, *expp;
468 	int an_int;
469 
470 	nd.dentry = NULL;
471 	exp.ex_path = NULL;
472 
473 	/* fs locations */
474 	exp.ex_fslocs.locations = NULL;
475 	exp.ex_fslocs.locations_count = 0;
476 	exp.ex_fslocs.migrated = 0;
477 
478 	exp.ex_uuid = NULL;
479 
480 	if (mesg[mlen-1] != '\n')
481 		return -EINVAL;
482 	mesg[mlen-1] = 0;
483 
484 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
485 	err = -ENOMEM;
486 	if (!buf) goto out;
487 
488 	/* client */
489 	len = qword_get(&mesg, buf, PAGE_SIZE);
490 	err = -EINVAL;
491 	if (len <= 0) goto out;
492 
493 	err = -ENOENT;
494 	dom = auth_domain_find(buf);
495 	if (!dom)
496 		goto out;
497 
498 	/* path */
499 	err = -EINVAL;
500 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
501 		goto out;
502 	err = path_lookup(buf, 0, &nd);
503 	if (err) goto out_no_path;
504 
505 	exp.h.flags = 0;
506 	exp.ex_client = dom;
507 	exp.ex_mnt = nd.mnt;
508 	exp.ex_dentry = nd.dentry;
509 	exp.ex_path = kstrdup(buf, GFP_KERNEL);
510 	err = -ENOMEM;
511 	if (!exp.ex_path)
512 		goto out;
513 
514 	/* expiry */
515 	err = -EINVAL;
516 	exp.h.expiry_time = get_expiry(&mesg);
517 	if (exp.h.expiry_time == 0)
518 		goto out;
519 
520 	/* flags */
521 	err = get_int(&mesg, &an_int);
522 	if (err == -ENOENT)
523 		set_bit(CACHE_NEGATIVE, &exp.h.flags);
524 	else {
525 		if (err || an_int < 0) goto out;
526 		exp.ex_flags= an_int;
527 
528 		/* anon uid */
529 		err = get_int(&mesg, &an_int);
530 		if (err) goto out;
531 		exp.ex_anon_uid= an_int;
532 
533 		/* anon gid */
534 		err = get_int(&mesg, &an_int);
535 		if (err) goto out;
536 		exp.ex_anon_gid= an_int;
537 
538 		/* fsid */
539 		err = get_int(&mesg, &an_int);
540 		if (err) goto out;
541 		exp.ex_fsid = an_int;
542 
543 		while ((len = qword_get(&mesg, buf, PAGE_SIZE)) > 0) {
544 			if (strcmp(buf, "fsloc") == 0)
545 				err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
546 			else if (strcmp(buf, "uuid") == 0) {
547 				/* expect a 16 byte uuid encoded as \xXXXX... */
548 				len = qword_get(&mesg, buf, PAGE_SIZE);
549 				if (len != 16)
550 					err  = -EINVAL;
551 				else {
552 					exp.ex_uuid =
553 						kmemdup(buf, 16, GFP_KERNEL);
554 					if (exp.ex_uuid == NULL)
555 						err = -ENOMEM;
556 				}
557 			} else
558 				/* quietly ignore unknown words and anything
559 				 * following. Newer user-space can try to set
560 				 * new values, then see what the result was.
561 				 */
562 				break;
563 			if (err)
564 				goto out;
565 		}
566 
567 		err = check_export(nd.dentry->d_inode, exp.ex_flags,
568 				   exp.ex_uuid);
569 		if (err) goto out;
570 	}
571 
572 	expp = svc_export_lookup(&exp);
573 	if (expp)
574 		expp = svc_export_update(&exp, expp);
575 	else
576 		err = -ENOMEM;
577 	cache_flush();
578 	if (expp == NULL)
579 		err = -ENOMEM;
580 	else
581 		exp_put(expp);
582  out:
583 	nfsd4_fslocs_free(&exp.ex_fslocs);
584 	kfree(exp.ex_uuid);
585  	kfree(exp.ex_path);
586 	if (nd.dentry)
587 		path_release(&nd);
588  out_no_path:
589 	if (dom)
590 		auth_domain_put(dom);
591 	kfree(buf);
592 	return err;
593 }
594 
595 static void exp_flags(struct seq_file *m, int flag, int fsid,
596 		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fslocs);
597 
598 static int svc_export_show(struct seq_file *m,
599 			   struct cache_detail *cd,
600 			   struct cache_head *h)
601 {
602 	struct svc_export *exp ;
603 
604 	if (h ==NULL) {
605 		seq_puts(m, "#path domain(flags)\n");
606 		return 0;
607 	}
608 	exp = container_of(h, struct svc_export, h);
609 	seq_path(m, exp->ex_mnt, exp->ex_dentry, " \t\n\\");
610 	seq_putc(m, '\t');
611 	seq_escape(m, exp->ex_client->name, " \t\n\\");
612 	seq_putc(m, '(');
613 	if (test_bit(CACHE_VALID, &h->flags) &&
614 	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
615 		exp_flags(m, exp->ex_flags, exp->ex_fsid,
616 			  exp->ex_anon_uid, exp->ex_anon_gid, &exp->ex_fslocs);
617 		if (exp->ex_uuid) {
618 			int i;
619 			seq_puts(m, ",uuid=");
620 			for (i=0; i<16; i++) {
621 				if ((i&3) == 0 && i)
622 					seq_putc(m, ':');
623 				seq_printf(m, "%02x", exp->ex_uuid[i]);
624 			}
625 		}
626 	}
627 	seq_puts(m, ")\n");
628 	return 0;
629 }
630 static int svc_export_match(struct cache_head *a, struct cache_head *b)
631 {
632 	struct svc_export *orig = container_of(a, struct svc_export, h);
633 	struct svc_export *new = container_of(b, struct svc_export, h);
634 	return orig->ex_client == new->ex_client &&
635 		orig->ex_dentry == new->ex_dentry &&
636 		orig->ex_mnt == new->ex_mnt;
637 }
638 
639 static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
640 {
641 	struct svc_export *new = container_of(cnew, struct svc_export, h);
642 	struct svc_export *item = container_of(citem, struct svc_export, h);
643 
644 	kref_get(&item->ex_client->ref);
645 	new->ex_client = item->ex_client;
646 	new->ex_dentry = dget(item->ex_dentry);
647 	new->ex_mnt = mntget(item->ex_mnt);
648 	new->ex_path = NULL;
649 	new->ex_fslocs.locations = NULL;
650 	new->ex_fslocs.locations_count = 0;
651 	new->ex_fslocs.migrated = 0;
652 }
653 
654 static void export_update(struct cache_head *cnew, struct cache_head *citem)
655 {
656 	struct svc_export *new = container_of(cnew, struct svc_export, h);
657 	struct svc_export *item = container_of(citem, struct svc_export, h);
658 
659 	new->ex_flags = item->ex_flags;
660 	new->ex_anon_uid = item->ex_anon_uid;
661 	new->ex_anon_gid = item->ex_anon_gid;
662 	new->ex_fsid = item->ex_fsid;
663 	new->ex_uuid = item->ex_uuid;
664 	item->ex_uuid = NULL;
665 	new->ex_path = item->ex_path;
666 	item->ex_path = NULL;
667 	new->ex_fslocs.locations = item->ex_fslocs.locations;
668 	item->ex_fslocs.locations = NULL;
669 	new->ex_fslocs.locations_count = item->ex_fslocs.locations_count;
670 	item->ex_fslocs.locations_count = 0;
671 	new->ex_fslocs.migrated = item->ex_fslocs.migrated;
672 	item->ex_fslocs.migrated = 0;
673 }
674 
675 static struct cache_head *svc_export_alloc(void)
676 {
677 	struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL);
678 	if (i)
679 		return &i->h;
680 	else
681 		return NULL;
682 }
683 
684 struct cache_detail svc_export_cache = {
685 	.owner		= THIS_MODULE,
686 	.hash_size	= EXPORT_HASHMAX,
687 	.hash_table	= export_table,
688 	.name		= "nfsd.export",
689 	.cache_put	= svc_export_put,
690 	.cache_request	= svc_export_request,
691 	.cache_parse	= svc_export_parse,
692 	.cache_show	= svc_export_show,
693 	.match		= svc_export_match,
694 	.init		= svc_export_init,
695 	.update		= export_update,
696 	.alloc		= svc_export_alloc,
697 };
698 
699 static struct svc_export *
700 svc_export_lookup(struct svc_export *exp)
701 {
702 	struct cache_head *ch;
703 	int hash;
704 	hash = hash_ptr(exp->ex_client, EXPORT_HASHBITS);
705 	hash ^= hash_ptr(exp->ex_dentry, EXPORT_HASHBITS);
706 	hash ^= hash_ptr(exp->ex_mnt, EXPORT_HASHBITS);
707 
708 	ch = sunrpc_cache_lookup(&svc_export_cache, &exp->h,
709 				 hash);
710 	if (ch)
711 		return container_of(ch, struct svc_export, h);
712 	else
713 		return NULL;
714 }
715 
716 static struct svc_export *
717 svc_export_update(struct svc_export *new, struct svc_export *old)
718 {
719 	struct cache_head *ch;
720 	int hash;
721 	hash = hash_ptr(old->ex_client, EXPORT_HASHBITS);
722 	hash ^= hash_ptr(old->ex_dentry, EXPORT_HASHBITS);
723 	hash ^= hash_ptr(old->ex_mnt, EXPORT_HASHBITS);
724 
725 	ch = sunrpc_cache_update(&svc_export_cache, &new->h,
726 				 &old->h,
727 				 hash);
728 	if (ch)
729 		return container_of(ch, struct svc_export, h);
730 	else
731 		return NULL;
732 }
733 
734 
735 static struct svc_expkey *
736 exp_find_key(svc_client *clp, int fsid_type, u32 *fsidv, struct cache_req *reqp)
737 {
738 	struct svc_expkey key, *ek;
739 	int err;
740 
741 	if (!clp)
742 		return NULL;
743 
744 	key.ek_client = clp;
745 	key.ek_fsidtype = fsid_type;
746 	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
747 
748 	ek = svc_expkey_lookup(&key);
749 	if (ek != NULL)
750 		if ((err = cache_check(&svc_expkey_cache, &ek->h, reqp)))
751 			ek = ERR_PTR(err);
752 	return ek;
753 }
754 
755 static int exp_set_key(svc_client *clp, int fsid_type, u32 *fsidv,
756 		       struct svc_export *exp)
757 {
758 	struct svc_expkey key, *ek;
759 
760 	key.ek_client = clp;
761 	key.ek_fsidtype = fsid_type;
762 	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
763 	key.ek_mnt = exp->ex_mnt;
764 	key.ek_dentry = exp->ex_dentry;
765 	key.h.expiry_time = NEVER;
766 	key.h.flags = 0;
767 
768 	ek = svc_expkey_lookup(&key);
769 	if (ek)
770 		ek = svc_expkey_update(&key,ek);
771 	if (ek) {
772 		cache_put(&ek->h, &svc_expkey_cache);
773 		return 0;
774 	}
775 	return -ENOMEM;
776 }
777 
778 /*
779  * Find the client's export entry matching xdev/xino.
780  */
781 static inline struct svc_expkey *
782 exp_get_key(svc_client *clp, dev_t dev, ino_t ino)
783 {
784 	u32 fsidv[3];
785 
786 	if (old_valid_dev(dev)) {
787 		mk_fsid(FSID_DEV, fsidv, dev, ino, 0, NULL);
788 		return exp_find_key(clp, FSID_DEV, fsidv, NULL);
789 	}
790 	mk_fsid(FSID_ENCODE_DEV, fsidv, dev, ino, 0, NULL);
791 	return exp_find_key(clp, FSID_ENCODE_DEV, fsidv, NULL);
792 }
793 
794 /*
795  * Find the client's export entry matching fsid
796  */
797 static inline struct svc_expkey *
798 exp_get_fsid_key(svc_client *clp, int fsid)
799 {
800 	u32 fsidv[2];
801 
802 	mk_fsid(FSID_NUM, fsidv, 0, 0, fsid, NULL);
803 
804 	return exp_find_key(clp, FSID_NUM, fsidv, NULL);
805 }
806 
807 svc_export *
808 exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
809 		struct cache_req *reqp)
810 {
811 	struct svc_export *exp, key;
812 
813 	if (!clp)
814 		return NULL;
815 
816 	key.ex_client = clp;
817 	key.ex_mnt = mnt;
818 	key.ex_dentry = dentry;
819 
820 	exp = svc_export_lookup(&key);
821 	if (exp != NULL)  {
822 		int err;
823 
824 		err = cache_check(&svc_export_cache, &exp->h, reqp);
825 		switch (err) {
826 		case 0: break;
827 		case -EAGAIN:
828 		case -ETIMEDOUT:
829 			exp = ERR_PTR(err);
830 			break;
831 		default:
832 			exp = NULL;
833 		}
834 	}
835 
836 	return exp;
837 }
838 
839 /*
840  * Find the export entry for a given dentry.
841  */
842 struct svc_export *
843 exp_parent(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
844 	   struct cache_req *reqp)
845 {
846 	svc_export *exp;
847 
848 	dget(dentry);
849 	exp = exp_get_by_name(clp, mnt, dentry, reqp);
850 
851 	while (exp == NULL && !IS_ROOT(dentry)) {
852 		struct dentry *parent;
853 
854 		parent = dget_parent(dentry);
855 		dput(dentry);
856 		dentry = parent;
857 		exp = exp_get_by_name(clp, mnt, dentry, reqp);
858 	}
859 	dput(dentry);
860 	return exp;
861 }
862 
863 /*
864  * Hashtable locking. Write locks are placed only by user processes
865  * wanting to modify export information.
866  * Write locking only done in this file.  Read locking
867  * needed externally.
868  */
869 
870 static DECLARE_RWSEM(hash_sem);
871 
872 void
873 exp_readlock(void)
874 {
875 	down_read(&hash_sem);
876 }
877 
878 static inline void
879 exp_writelock(void)
880 {
881 	down_write(&hash_sem);
882 }
883 
884 void
885 exp_readunlock(void)
886 {
887 	up_read(&hash_sem);
888 }
889 
890 static inline void
891 exp_writeunlock(void)
892 {
893 	up_write(&hash_sem);
894 }
895 
896 static void exp_fsid_unhash(struct svc_export *exp)
897 {
898 	struct svc_expkey *ek;
899 
900 	if ((exp->ex_flags & NFSEXP_FSID) == 0)
901 		return;
902 
903 	ek = exp_get_fsid_key(exp->ex_client, exp->ex_fsid);
904 	if (ek && !IS_ERR(ek)) {
905 		ek->h.expiry_time = get_seconds()-1;
906 		cache_put(&ek->h, &svc_expkey_cache);
907 	}
908 	svc_expkey_cache.nextcheck = get_seconds();
909 }
910 
911 static int exp_fsid_hash(svc_client *clp, struct svc_export *exp)
912 {
913 	u32 fsid[2];
914 
915 	if ((exp->ex_flags & NFSEXP_FSID) == 0)
916 		return 0;
917 
918 	mk_fsid(FSID_NUM, fsid, 0, 0, exp->ex_fsid, NULL);
919 	return exp_set_key(clp, FSID_NUM, fsid, exp);
920 }
921 
922 static int exp_hash(struct auth_domain *clp, struct svc_export *exp)
923 {
924 	u32 fsid[2];
925 	struct inode *inode = exp->ex_dentry->d_inode;
926 	dev_t dev = inode->i_sb->s_dev;
927 
928 	if (old_valid_dev(dev)) {
929 		mk_fsid(FSID_DEV, fsid, dev, inode->i_ino, 0, NULL);
930 		return exp_set_key(clp, FSID_DEV, fsid, exp);
931 	}
932 	mk_fsid(FSID_ENCODE_DEV, fsid, dev, inode->i_ino, 0, NULL);
933 	return exp_set_key(clp, FSID_ENCODE_DEV, fsid, exp);
934 }
935 
936 static void exp_unhash(struct svc_export *exp)
937 {
938 	struct svc_expkey *ek;
939 	struct inode *inode = exp->ex_dentry->d_inode;
940 
941 	ek = exp_get_key(exp->ex_client, inode->i_sb->s_dev, inode->i_ino);
942 	if (ek && !IS_ERR(ek)) {
943 		ek->h.expiry_time = get_seconds()-1;
944 		cache_put(&ek->h, &svc_expkey_cache);
945 	}
946 	svc_expkey_cache.nextcheck = get_seconds();
947 }
948 
949 /*
950  * Export a file system.
951  */
952 int
953 exp_export(struct nfsctl_export *nxp)
954 {
955 	svc_client	*clp;
956 	struct svc_export	*exp = NULL;
957 	struct svc_export	new;
958 	struct svc_expkey	*fsid_key = NULL;
959 	struct nameidata nd;
960 	int		err;
961 
962 	/* Consistency check */
963 	err = -EINVAL;
964 	if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
965 	    !exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
966 		goto out;
967 
968 	dprintk("exp_export called for %s:%s (%x/%ld fl %x).\n",
969 			nxp->ex_client, nxp->ex_path,
970 			(unsigned)nxp->ex_dev, (long)nxp->ex_ino,
971 			nxp->ex_flags);
972 
973 	/* Try to lock the export table for update */
974 	exp_writelock();
975 
976 	/* Look up client info */
977 	if (!(clp = auth_domain_find(nxp->ex_client)))
978 		goto out_unlock;
979 
980 
981 	/* Look up the dentry */
982 	err = path_lookup(nxp->ex_path, 0, &nd);
983 	if (err)
984 		goto out_unlock;
985 	err = -EINVAL;
986 
987 	exp = exp_get_by_name(clp, nd.mnt, nd.dentry, NULL);
988 
989 	memset(&new, 0, sizeof(new));
990 
991 	/* must make sure there won't be an ex_fsid clash */
992 	if ((nxp->ex_flags & NFSEXP_FSID) &&
993 	    (fsid_key = exp_get_fsid_key(clp, nxp->ex_dev)) &&
994 	    !IS_ERR(fsid_key) &&
995 	    fsid_key->ek_mnt &&
996 	    (fsid_key->ek_mnt != nd.mnt || fsid_key->ek_dentry != nd.dentry) )
997 		goto finish;
998 
999 	if (exp) {
1000 		/* just a flags/id/fsid update */
1001 
1002 		exp_fsid_unhash(exp);
1003 		exp->ex_flags    = nxp->ex_flags;
1004 		exp->ex_anon_uid = nxp->ex_anon_uid;
1005 		exp->ex_anon_gid = nxp->ex_anon_gid;
1006 		exp->ex_fsid     = nxp->ex_dev;
1007 
1008 		err = exp_fsid_hash(clp, exp);
1009 		goto finish;
1010 	}
1011 
1012 	err = check_export(nd.dentry->d_inode, nxp->ex_flags, NULL);
1013 	if (err) goto finish;
1014 
1015 	err = -ENOMEM;
1016 
1017 	dprintk("nfsd: creating export entry %p for client %p\n", exp, clp);
1018 
1019 	new.h.expiry_time = NEVER;
1020 	new.h.flags = 0;
1021 	new.ex_path = kstrdup(nxp->ex_path, GFP_KERNEL);
1022 	if (!new.ex_path)
1023 		goto finish;
1024 	new.ex_client = clp;
1025 	new.ex_mnt = nd.mnt;
1026 	new.ex_dentry = nd.dentry;
1027 	new.ex_flags = nxp->ex_flags;
1028 	new.ex_anon_uid = nxp->ex_anon_uid;
1029 	new.ex_anon_gid = nxp->ex_anon_gid;
1030 	new.ex_fsid = nxp->ex_dev;
1031 
1032 	exp = svc_export_lookup(&new);
1033 	if (exp)
1034 		exp = svc_export_update(&new, exp);
1035 
1036 	if (!exp)
1037 		goto finish;
1038 
1039 	if (exp_hash(clp, exp) ||
1040 	    exp_fsid_hash(clp, exp)) {
1041 		/* failed to create at least one index */
1042 		exp_do_unexport(exp);
1043 		cache_flush();
1044 	} else
1045 		err = 0;
1046 finish:
1047 	if (new.ex_path)
1048 		kfree(new.ex_path);
1049 	if (exp)
1050 		exp_put(exp);
1051 	if (fsid_key && !IS_ERR(fsid_key))
1052 		cache_put(&fsid_key->h, &svc_expkey_cache);
1053 	if (clp)
1054 		auth_domain_put(clp);
1055 	path_release(&nd);
1056 out_unlock:
1057 	exp_writeunlock();
1058 out:
1059 	return err;
1060 }
1061 
1062 /*
1063  * Unexport a file system. The export entry has already
1064  * been removed from the client's list of exported fs's.
1065  */
1066 static void
1067 exp_do_unexport(svc_export *unexp)
1068 {
1069 	unexp->h.expiry_time = get_seconds()-1;
1070 	svc_export_cache.nextcheck = get_seconds();
1071 	exp_unhash(unexp);
1072 	exp_fsid_unhash(unexp);
1073 }
1074 
1075 
1076 /*
1077  * unexport syscall.
1078  */
1079 int
1080 exp_unexport(struct nfsctl_export *nxp)
1081 {
1082 	struct auth_domain *dom;
1083 	svc_export *exp;
1084 	struct nameidata nd;
1085 	int		err;
1086 
1087 	/* Consistency check */
1088 	if (!exp_verify_string(nxp->ex_path, NFS_MAXPATHLEN) ||
1089 	    !exp_verify_string(nxp->ex_client, NFSCLNT_IDMAX))
1090 		return -EINVAL;
1091 
1092 	exp_writelock();
1093 
1094 	err = -EINVAL;
1095 	dom = auth_domain_find(nxp->ex_client);
1096 	if (!dom) {
1097 		dprintk("nfsd: unexport couldn't find %s\n", nxp->ex_client);
1098 		goto out_unlock;
1099 	}
1100 
1101 	err = path_lookup(nxp->ex_path, 0, &nd);
1102 	if (err)
1103 		goto out_domain;
1104 
1105 	err = -EINVAL;
1106 	exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);
1107 	path_release(&nd);
1108 	if (!exp)
1109 		goto out_domain;
1110 
1111 	exp_do_unexport(exp);
1112 	exp_put(exp);
1113 	err = 0;
1114 
1115 out_domain:
1116 	auth_domain_put(dom);
1117 	cache_flush();
1118 out_unlock:
1119 	exp_writeunlock();
1120 	return err;
1121 }
1122 
1123 /*
1124  * Obtain the root fh on behalf of a client.
1125  * This could be done in user space, but I feel that it adds some safety
1126  * since its harder to fool a kernel module than a user space program.
1127  */
1128 int
1129 exp_rootfh(svc_client *clp, char *path, struct knfsd_fh *f, int maxsize)
1130 {
1131 	struct svc_export	*exp;
1132 	struct nameidata	nd;
1133 	struct inode		*inode;
1134 	struct svc_fh		fh;
1135 	int			err;
1136 
1137 	err = -EPERM;
1138 	/* NB: we probably ought to check that it's NUL-terminated */
1139 	if (path_lookup(path, 0, &nd)) {
1140 		printk("nfsd: exp_rootfh path not found %s", path);
1141 		return err;
1142 	}
1143 	inode = nd.dentry->d_inode;
1144 
1145 	dprintk("nfsd: exp_rootfh(%s [%p] %s:%s/%ld)\n",
1146 		 path, nd.dentry, clp->name,
1147 		 inode->i_sb->s_id, inode->i_ino);
1148 	exp = exp_parent(clp, nd.mnt, nd.dentry, NULL);
1149 	if (IS_ERR(exp)) {
1150 		err = PTR_ERR(exp);
1151 		goto out;
1152 	}
1153 	if (!exp) {
1154 		dprintk("nfsd: exp_rootfh export not found.\n");
1155 		goto out;
1156 	}
1157 
1158 	/*
1159 	 * fh must be initialized before calling fh_compose
1160 	 */
1161 	fh_init(&fh, maxsize);
1162 	if (fh_compose(&fh, exp, nd.dentry, NULL))
1163 		err = -EINVAL;
1164 	else
1165 		err = 0;
1166 	memcpy(f, &fh.fh_handle, sizeof(struct knfsd_fh));
1167 	fh_put(&fh);
1168 	exp_put(exp);
1169 out:
1170 	path_release(&nd);
1171 	return err;
1172 }
1173 
1174 struct svc_export *
1175 exp_find(struct auth_domain *clp, int fsid_type, u32 *fsidv,
1176 	 struct cache_req *reqp)
1177 {
1178 	struct svc_export *exp;
1179 	struct svc_expkey *ek = exp_find_key(clp, fsid_type, fsidv, reqp);
1180 	if (!ek || IS_ERR(ek))
1181 		return ERR_PTR(PTR_ERR(ek));
1182 
1183 	exp = exp_get_by_name(clp, ek->ek_mnt, ek->ek_dentry, reqp);
1184 	cache_put(&ek->h, &svc_expkey_cache);
1185 
1186 	if (!exp || IS_ERR(exp))
1187 		return ERR_PTR(PTR_ERR(exp));
1188 	return exp;
1189 }
1190 
1191 
1192 /*
1193  * Called when we need the filehandle for the root of the pseudofs,
1194  * for a given NFSv4 client.   The root is defined to be the
1195  * export point with fsid==0
1196  */
1197 __be32
1198 exp_pseudoroot(struct auth_domain *clp, struct svc_fh *fhp,
1199 	       struct cache_req *creq)
1200 {
1201 	struct svc_export *exp;
1202 	__be32 rv;
1203 	u32 fsidv[2];
1204 
1205 	mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
1206 
1207 	exp = exp_find(clp, FSID_NUM, fsidv, creq);
1208 	if (IS_ERR(exp))
1209 		return nfserrno(PTR_ERR(exp));
1210 	if (exp == NULL)
1211 		return nfserr_perm;
1212 	rv = fh_compose(fhp, exp, exp->ex_dentry, NULL);
1213 	exp_put(exp);
1214 	return rv;
1215 }
1216 
1217 /* Iterator */
1218 
1219 static void *e_start(struct seq_file *m, loff_t *pos)
1220 	__acquires(svc_export_cache.hash_lock)
1221 {
1222 	loff_t n = *pos;
1223 	unsigned hash, export;
1224 	struct cache_head *ch;
1225 
1226 	exp_readlock();
1227 	read_lock(&svc_export_cache.hash_lock);
1228 	if (!n--)
1229 		return SEQ_START_TOKEN;
1230 	hash = n >> 32;
1231 	export = n & ((1LL<<32) - 1);
1232 
1233 
1234 	for (ch=export_table[hash]; ch; ch=ch->next)
1235 		if (!export--)
1236 			return ch;
1237 	n &= ~((1LL<<32) - 1);
1238 	do {
1239 		hash++;
1240 		n += 1LL<<32;
1241 	} while(hash < EXPORT_HASHMAX && export_table[hash]==NULL);
1242 	if (hash >= EXPORT_HASHMAX)
1243 		return NULL;
1244 	*pos = n+1;
1245 	return export_table[hash];
1246 }
1247 
1248 static void *e_next(struct seq_file *m, void *p, loff_t *pos)
1249 {
1250 	struct cache_head *ch = p;
1251 	int hash = (*pos >> 32);
1252 
1253 	if (p == SEQ_START_TOKEN)
1254 		hash = 0;
1255 	else if (ch->next == NULL) {
1256 		hash++;
1257 		*pos += 1LL<<32;
1258 	} else {
1259 		++*pos;
1260 		return ch->next;
1261 	}
1262 	*pos &= ~((1LL<<32) - 1);
1263 	while (hash < EXPORT_HASHMAX && export_table[hash] == NULL) {
1264 		hash++;
1265 		*pos += 1LL<<32;
1266 	}
1267 	if (hash >= EXPORT_HASHMAX)
1268 		return NULL;
1269 	++*pos;
1270 	return export_table[hash];
1271 }
1272 
1273 static void e_stop(struct seq_file *m, void *p)
1274 	__releases(svc_export_cache.hash_lock)
1275 {
1276 	read_unlock(&svc_export_cache.hash_lock);
1277 	exp_readunlock();
1278 }
1279 
1280 static struct flags {
1281 	int flag;
1282 	char *name[2];
1283 } expflags[] = {
1284 	{ NFSEXP_READONLY, {"ro", "rw"}},
1285 	{ NFSEXP_INSECURE_PORT, {"insecure", ""}},
1286 	{ NFSEXP_ROOTSQUASH, {"root_squash", "no_root_squash"}},
1287 	{ NFSEXP_ALLSQUASH, {"all_squash", ""}},
1288 	{ NFSEXP_ASYNC, {"async", "sync"}},
1289 	{ NFSEXP_GATHERED_WRITES, {"wdelay", "no_wdelay"}},
1290 	{ NFSEXP_NOHIDE, {"nohide", ""}},
1291 	{ NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
1292 	{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
1293 	{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
1294 #ifdef MSNFS
1295 	{ NFSEXP_MSNFS, {"msnfs", ""}},
1296 #endif
1297 	{ 0, {"", ""}}
1298 };
1299 
1300 static void exp_flags(struct seq_file *m, int flag, int fsid,
1301 		uid_t anonu, uid_t anong, struct nfsd4_fs_locations *fsloc)
1302 {
1303 	int first = 0;
1304 	struct flags *flg;
1305 
1306 	for (flg = expflags; flg->flag; flg++) {
1307 		int state = (flg->flag & flag)?0:1;
1308 		if (*flg->name[state])
1309 			seq_printf(m, "%s%s", first++?",":"", flg->name[state]);
1310 	}
1311 	if (flag & NFSEXP_FSID)
1312 		seq_printf(m, "%sfsid=%d", first++?",":"", fsid);
1313 	if (anonu != (uid_t)-2 && anonu != (0x10000-2))
1314 		seq_printf(m, "%sanonuid=%d", first++?",":"", anonu);
1315 	if (anong != (gid_t)-2 && anong != (0x10000-2))
1316 		seq_printf(m, "%sanongid=%d", first++?",":"", anong);
1317 	if (fsloc && fsloc->locations_count > 0) {
1318 		char *loctype = (fsloc->migrated) ? "refer" : "replicas";
1319 		int i;
1320 
1321 		seq_printf(m, "%s%s=", first++?",":"", loctype);
1322 		seq_escape(m, fsloc->locations[0].path, ",;@ \t\n\\");
1323 		seq_putc(m, '@');
1324 		seq_escape(m, fsloc->locations[0].hosts, ",;@ \t\n\\");
1325 		for (i = 1; i < fsloc->locations_count; i++) {
1326 			seq_putc(m, ';');
1327 			seq_escape(m, fsloc->locations[i].path, ",;@ \t\n\\");
1328 			seq_putc(m, '@');
1329 			seq_escape(m, fsloc->locations[i].hosts, ",;@ \t\n\\");
1330 		}
1331 	}
1332 }
1333 
1334 static int e_show(struct seq_file *m, void *p)
1335 {
1336 	struct cache_head *cp = p;
1337 	struct svc_export *exp = container_of(cp, struct svc_export, h);
1338 
1339 	if (p == SEQ_START_TOKEN) {
1340 		seq_puts(m, "# Version 1.1\n");
1341 		seq_puts(m, "# Path Client(Flags) # IPs\n");
1342 		return 0;
1343 	}
1344 
1345 	cache_get(&exp->h);
1346 	if (cache_check(&svc_export_cache, &exp->h, NULL))
1347 		return 0;
1348 	cache_put(&exp->h, &svc_export_cache);
1349 	return svc_export_show(m, &svc_export_cache, cp);
1350 }
1351 
1352 struct seq_operations nfs_exports_op = {
1353 	.start	= e_start,
1354 	.next	= e_next,
1355 	.stop	= e_stop,
1356 	.show	= e_show,
1357 };
1358 
1359 /*
1360  * Add or modify a client.
1361  * Change requests may involve the list of host addresses. The list of
1362  * exports and possibly existing uid maps are left untouched.
1363  */
1364 int
1365 exp_addclient(struct nfsctl_client *ncp)
1366 {
1367 	struct auth_domain	*dom;
1368 	int			i, err;
1369 
1370 	/* First, consistency check. */
1371 	err = -EINVAL;
1372 	if (! exp_verify_string(ncp->cl_ident, NFSCLNT_IDMAX))
1373 		goto out;
1374 	if (ncp->cl_naddr > NFSCLNT_ADDRMAX)
1375 		goto out;
1376 
1377 	/* Lock the hashtable */
1378 	exp_writelock();
1379 
1380 	dom = unix_domain_find(ncp->cl_ident);
1381 
1382 	err = -ENOMEM;
1383 	if (!dom)
1384 		goto out_unlock;
1385 
1386 	/* Insert client into hashtable. */
1387 	for (i = 0; i < ncp->cl_naddr; i++)
1388 		auth_unix_add_addr(ncp->cl_addrlist[i], dom);
1389 
1390 	auth_unix_forget_old(dom);
1391 	auth_domain_put(dom);
1392 
1393 	err = 0;
1394 
1395 out_unlock:
1396 	exp_writeunlock();
1397 out:
1398 	return err;
1399 }
1400 
1401 /*
1402  * Delete a client given an identifier.
1403  */
1404 int
1405 exp_delclient(struct nfsctl_client *ncp)
1406 {
1407 	int		err;
1408 	struct auth_domain *dom;
1409 
1410 	err = -EINVAL;
1411 	if (!exp_verify_string(ncp->cl_ident, NFSCLNT_IDMAX))
1412 		goto out;
1413 
1414 	/* Lock the hashtable */
1415 	exp_writelock();
1416 
1417 	dom = auth_domain_find(ncp->cl_ident);
1418 	/* just make sure that no addresses work
1419 	 * and that it will expire soon
1420 	 */
1421 	if (dom) {
1422 		err = auth_unix_forget_old(dom);
1423 		auth_domain_put(dom);
1424 	}
1425 
1426 	exp_writeunlock();
1427 out:
1428 	return err;
1429 }
1430 
1431 /*
1432  * Verify that string is non-empty and does not exceed max length.
1433  */
1434 static int
1435 exp_verify_string(char *cp, int max)
1436 {
1437 	int	i;
1438 
1439 	for (i = 0; i < max; i++)
1440 		if (!cp[i])
1441 			return i;
1442 	cp[i] = 0;
1443 	printk(KERN_NOTICE "nfsd: couldn't validate string %s\n", cp);
1444 	return 0;
1445 }
1446 
1447 /*
1448  * Initialize the exports module.
1449  */
1450 void
1451 nfsd_export_init(void)
1452 {
1453 	dprintk("nfsd: initializing export module.\n");
1454 
1455 	cache_register(&svc_export_cache);
1456 	cache_register(&svc_expkey_cache);
1457 
1458 }
1459 
1460 /*
1461  * Flush exports table - called when last nfsd thread is killed
1462  */
1463 void
1464 nfsd_export_flush(void)
1465 {
1466 	exp_writelock();
1467 	cache_purge(&svc_expkey_cache);
1468 	cache_purge(&svc_export_cache);
1469 	exp_writeunlock();
1470 }
1471 
1472 /*
1473  * Shutdown the exports module.
1474  */
1475 void
1476 nfsd_export_shutdown(void)
1477 {
1478 
1479 	dprintk("nfsd: shutting down export module.\n");
1480 
1481 	exp_writelock();
1482 
1483 	if (cache_unregister(&svc_expkey_cache))
1484 		printk(KERN_ERR "nfsd: failed to unregister expkey cache\n");
1485 	if (cache_unregister(&svc_export_cache))
1486 		printk(KERN_ERR "nfsd: failed to unregister export cache\n");
1487 	svcauth_unix_purge();
1488 
1489 	exp_writeunlock();
1490 	dprintk("nfsd: export shutdown complete.\n");
1491 }
1492