xref: /openbmc/linux/fs/nfs/client.c (revision b60a5b8d)
1 /* client.c: NFS client sharing and management code
2  *
3  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/sched.h>
16 #include <linux/time.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/stat.h>
21 #include <linux/errno.h>
22 #include <linux/unistd.h>
23 #include <linux/sunrpc/addr.h>
24 #include <linux/sunrpc/clnt.h>
25 #include <linux/sunrpc/stats.h>
26 #include <linux/sunrpc/metrics.h>
27 #include <linux/sunrpc/xprtsock.h>
28 #include <linux/sunrpc/xprtrdma.h>
29 #include <linux/nfs_fs.h>
30 #include <linux/nfs_mount.h>
31 #include <linux/nfs4_mount.h>
32 #include <linux/lockd/bind.h>
33 #include <linux/seq_file.h>
34 #include <linux/mount.h>
35 #include <linux/vfs.h>
36 #include <linux/inet.h>
37 #include <linux/in6.h>
38 #include <linux/slab.h>
39 #include <linux/idr.h>
40 #include <net/ipv6.h>
41 #include <linux/nfs_xdr.h>
42 #include <linux/sunrpc/bc_xprt.h>
43 #include <linux/nsproxy.h>
44 #include <linux/pid_namespace.h>
45 
46 
47 #include "nfs4_fs.h"
48 #include "callback.h"
49 #include "delegation.h"
50 #include "iostat.h"
51 #include "internal.h"
52 #include "fscache.h"
53 #include "pnfs.h"
54 #include "nfs.h"
55 #include "netns.h"
56 
57 #define NFSDBG_FACILITY		NFSDBG_CLIENT
58 
59 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
60 static DEFINE_SPINLOCK(nfs_version_lock);
61 static DEFINE_MUTEX(nfs_version_mutex);
62 static LIST_HEAD(nfs_versions);
63 
64 /*
65  * RPC cruft for NFS
66  */
67 static const struct rpc_version *nfs_version[5] = {
68 	[2] = NULL,
69 	[3] = NULL,
70 	[4] = NULL,
71 };
72 
73 const struct rpc_program nfs_program = {
74 	.name			= "nfs",
75 	.number			= NFS_PROGRAM,
76 	.nrvers			= ARRAY_SIZE(nfs_version),
77 	.version		= nfs_version,
78 	.stats			= &nfs_rpcstat,
79 	.pipe_dir_name		= NFS_PIPE_DIRNAME,
80 };
81 
82 struct rpc_stat nfs_rpcstat = {
83 	.program		= &nfs_program
84 };
85 
86 static struct nfs_subversion *find_nfs_version(unsigned int version)
87 {
88 	struct nfs_subversion *nfs;
89 	spin_lock(&nfs_version_lock);
90 
91 	list_for_each_entry(nfs, &nfs_versions, list) {
92 		if (nfs->rpc_ops->version == version) {
93 			spin_unlock(&nfs_version_lock);
94 			return nfs;
95 		}
96 	}
97 
98 	spin_unlock(&nfs_version_lock);
99 	return ERR_PTR(-EPROTONOSUPPORT);
100 }
101 
102 struct nfs_subversion *get_nfs_version(unsigned int version)
103 {
104 	struct nfs_subversion *nfs = find_nfs_version(version);
105 
106 	if (IS_ERR(nfs)) {
107 		mutex_lock(&nfs_version_mutex);
108 		request_module("nfsv%d", version);
109 		nfs = find_nfs_version(version);
110 		mutex_unlock(&nfs_version_mutex);
111 	}
112 
113 	if (!IS_ERR(nfs) && !try_module_get(nfs->owner))
114 		return ERR_PTR(-EAGAIN);
115 	return nfs;
116 }
117 
118 void put_nfs_version(struct nfs_subversion *nfs)
119 {
120 	module_put(nfs->owner);
121 }
122 
123 void register_nfs_version(struct nfs_subversion *nfs)
124 {
125 	spin_lock(&nfs_version_lock);
126 
127 	list_add(&nfs->list, &nfs_versions);
128 	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
129 
130 	spin_unlock(&nfs_version_lock);
131 }
132 EXPORT_SYMBOL_GPL(register_nfs_version);
133 
134 void unregister_nfs_version(struct nfs_subversion *nfs)
135 {
136 	spin_lock(&nfs_version_lock);
137 
138 	nfs_version[nfs->rpc_ops->version] = NULL;
139 	list_del(&nfs->list);
140 
141 	spin_unlock(&nfs_version_lock);
142 }
143 EXPORT_SYMBOL_GPL(unregister_nfs_version);
144 
145 /*
146  * Allocate a shared client record
147  *
148  * Since these are allocated/deallocated very rarely, we don't
149  * bother putting them in a slab cache...
150  */
151 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
152 {
153 	struct nfs_client *clp;
154 	int err = -ENOMEM;
155 
156 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
157 		goto error_0;
158 
159 	clp->cl_nfs_mod = cl_init->nfs_mod;
160 	if (!try_module_get(clp->cl_nfs_mod->owner))
161 		goto error_dealloc;
162 
163 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
164 
165 	refcount_set(&clp->cl_count, 1);
166 	clp->cl_cons_state = NFS_CS_INITING;
167 
168 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
169 	clp->cl_addrlen = cl_init->addrlen;
170 
171 	if (cl_init->hostname) {
172 		err = -ENOMEM;
173 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
174 		if (!clp->cl_hostname)
175 			goto error_cleanup;
176 	}
177 
178 	INIT_LIST_HEAD(&clp->cl_superblocks);
179 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
180 
181 	clp->cl_proto = cl_init->proto;
182 	clp->cl_net = get_net(cl_init->net);
183 
184 	clp->cl_principal = "*";
185 	nfs_fscache_get_client_cookie(clp);
186 
187 	return clp;
188 
189 error_cleanup:
190 	put_nfs_version(clp->cl_nfs_mod);
191 error_dealloc:
192 	kfree(clp);
193 error_0:
194 	return ERR_PTR(err);
195 }
196 EXPORT_SYMBOL_GPL(nfs_alloc_client);
197 
198 #if IS_ENABLED(CONFIG_NFS_V4)
199 void nfs_cleanup_cb_ident_idr(struct net *net)
200 {
201 	struct nfs_net *nn = net_generic(net, nfs_net_id);
202 
203 	idr_destroy(&nn->cb_ident_idr);
204 }
205 
206 /* nfs_client_lock held */
207 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
208 {
209 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
210 
211 	if (clp->cl_cb_ident)
212 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
213 }
214 
215 static void pnfs_init_server(struct nfs_server *server)
216 {
217 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
218 }
219 
220 #else
221 void nfs_cleanup_cb_ident_idr(struct net *net)
222 {
223 }
224 
225 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
226 {
227 }
228 
229 static void pnfs_init_server(struct nfs_server *server)
230 {
231 }
232 
233 #endif /* CONFIG_NFS_V4 */
234 
235 /*
236  * Destroy a shared client record
237  */
238 void nfs_free_client(struct nfs_client *clp)
239 {
240 	nfs_fscache_release_client_cookie(clp);
241 
242 	/* -EIO all pending I/O */
243 	if (!IS_ERR(clp->cl_rpcclient))
244 		rpc_shutdown_client(clp->cl_rpcclient);
245 
246 	put_net(clp->cl_net);
247 	put_nfs_version(clp->cl_nfs_mod);
248 	kfree(clp->cl_hostname);
249 	kfree(clp->cl_acceptor);
250 	kfree(clp);
251 }
252 EXPORT_SYMBOL_GPL(nfs_free_client);
253 
254 /*
255  * Release a reference to a shared client record
256  */
257 void nfs_put_client(struct nfs_client *clp)
258 {
259 	struct nfs_net *nn;
260 
261 	if (!clp)
262 		return;
263 
264 	nn = net_generic(clp->cl_net, nfs_net_id);
265 
266 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
267 		list_del(&clp->cl_share_link);
268 		nfs_cb_idr_remove_locked(clp);
269 		spin_unlock(&nn->nfs_client_lock);
270 
271 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
272 
273 		clp->rpc_ops->free_client(clp);
274 	}
275 }
276 EXPORT_SYMBOL_GPL(nfs_put_client);
277 
278 /*
279  * Find an nfs_client on the list that matches the initialisation data
280  * that is supplied.
281  */
282 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
283 {
284 	struct nfs_client *clp;
285 	const struct sockaddr *sap = data->addr;
286 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
287 
288 again:
289 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
290 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
291 		/* Don't match clients that failed to initialise properly */
292 		if (clp->cl_cons_state < 0)
293 			continue;
294 
295 		/* If a client is still initializing then we need to wait */
296 		if (clp->cl_cons_state > NFS_CS_READY) {
297 			refcount_inc(&clp->cl_count);
298 			spin_unlock(&nn->nfs_client_lock);
299 			nfs_wait_client_init_complete(clp);
300 			nfs_put_client(clp);
301 			spin_lock(&nn->nfs_client_lock);
302 			goto again;
303 		}
304 
305 		/* Different NFS versions cannot share the same nfs_client */
306 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
307 			continue;
308 
309 		if (clp->cl_proto != data->proto)
310 			continue;
311 		/* Match nfsv4 minorversion */
312 		if (clp->cl_minorversion != data->minorversion)
313 			continue;
314 		/* Match the full socket address */
315 		if (!rpc_cmp_addr_port(sap, clap))
316 			/* Match all xprt_switch full socket addresses */
317 			if (IS_ERR(clp->cl_rpcclient) ||
318                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
319 							   sap))
320 				continue;
321 
322 		refcount_inc(&clp->cl_count);
323 		return clp;
324 	}
325 	return NULL;
326 }
327 
328 /*
329  * Return true if @clp is done initializing, false if still working on it.
330  *
331  * Use nfs_client_init_status to check if it was successful.
332  */
333 bool nfs_client_init_is_complete(const struct nfs_client *clp)
334 {
335 	return clp->cl_cons_state <= NFS_CS_READY;
336 }
337 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
338 
339 /*
340  * Return 0 if @clp was successfully initialized, -errno otherwise.
341  *
342  * This must be called *after* nfs_client_init_is_complete() returns true,
343  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
344  */
345 int nfs_client_init_status(const struct nfs_client *clp)
346 {
347 	/* called without checking nfs_client_init_is_complete */
348 	if (clp->cl_cons_state > NFS_CS_READY) {
349 		WARN_ON_ONCE(1);
350 		return -EINVAL;
351 	}
352 	return clp->cl_cons_state;
353 }
354 EXPORT_SYMBOL_GPL(nfs_client_init_status);
355 
356 int nfs_wait_client_init_complete(const struct nfs_client *clp)
357 {
358 	return wait_event_killable(nfs_client_active_wq,
359 			nfs_client_init_is_complete(clp));
360 }
361 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
362 
363 /*
364  * Found an existing client.  Make sure it's ready before returning.
365  */
366 static struct nfs_client *
367 nfs_found_client(const struct nfs_client_initdata *cl_init,
368 		 struct nfs_client *clp)
369 {
370 	int error;
371 
372 	error = nfs_wait_client_init_complete(clp);
373 	if (error < 0) {
374 		nfs_put_client(clp);
375 		return ERR_PTR(-ERESTARTSYS);
376 	}
377 
378 	if (clp->cl_cons_state < NFS_CS_READY) {
379 		error = clp->cl_cons_state;
380 		nfs_put_client(clp);
381 		return ERR_PTR(error);
382 	}
383 
384 	smp_rmb();
385 	return clp;
386 }
387 
388 /*
389  * Look up a client by IP address and protocol version
390  * - creates a new record if one doesn't yet exist
391  */
392 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
393 {
394 	struct nfs_client *clp, *new = NULL;
395 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
396 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
397 
398 	if (cl_init->hostname == NULL) {
399 		WARN_ON(1);
400 		return NULL;
401 	}
402 
403 	/* see if the client already exists */
404 	do {
405 		spin_lock(&nn->nfs_client_lock);
406 
407 		clp = nfs_match_client(cl_init);
408 		if (clp) {
409 			spin_unlock(&nn->nfs_client_lock);
410 			if (new)
411 				new->rpc_ops->free_client(new);
412 			return nfs_found_client(cl_init, clp);
413 		}
414 		if (new) {
415 			list_add_tail(&new->cl_share_link,
416 					&nn->nfs_client_list);
417 			spin_unlock(&nn->nfs_client_lock);
418 			new->cl_flags = cl_init->init_flags;
419 			return rpc_ops->init_client(new, cl_init);
420 		}
421 
422 		spin_unlock(&nn->nfs_client_lock);
423 
424 		new = rpc_ops->alloc_client(cl_init);
425 	} while (!IS_ERR(new));
426 
427 	return new;
428 }
429 EXPORT_SYMBOL_GPL(nfs_get_client);
430 
431 /*
432  * Mark a server as ready or failed
433  */
434 void nfs_mark_client_ready(struct nfs_client *clp, int state)
435 {
436 	smp_wmb();
437 	clp->cl_cons_state = state;
438 	wake_up_all(&nfs_client_active_wq);
439 }
440 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
441 
442 /*
443  * Initialise the timeout values for a connection
444  */
445 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
446 				    int timeo, int retrans)
447 {
448 	to->to_initval = timeo * HZ / 10;
449 	to->to_retries = retrans;
450 
451 	switch (proto) {
452 	case XPRT_TRANSPORT_TCP:
453 	case XPRT_TRANSPORT_RDMA:
454 		if (retrans == NFS_UNSPEC_RETRANS)
455 			to->to_retries = NFS_DEF_TCP_RETRANS;
456 		if (timeo == NFS_UNSPEC_TIMEO || to->to_retries == 0)
457 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
458 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
459 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
460 		to->to_increment = to->to_initval;
461 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
462 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
463 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
464 		if (to->to_maxval < to->to_initval)
465 			to->to_maxval = to->to_initval;
466 		to->to_exponential = 0;
467 		break;
468 	case XPRT_TRANSPORT_UDP:
469 		if (retrans == NFS_UNSPEC_RETRANS)
470 			to->to_retries = NFS_DEF_UDP_RETRANS;
471 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
472 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
473 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
474 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
475 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
476 		to->to_exponential = 1;
477 		break;
478 	default:
479 		BUG();
480 	}
481 }
482 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
483 
484 /*
485  * Create an RPC client handle
486  */
487 int nfs_create_rpc_client(struct nfs_client *clp,
488 			  const struct nfs_client_initdata *cl_init,
489 			  rpc_authflavor_t flavor)
490 {
491 	struct rpc_clnt		*clnt = NULL;
492 	struct rpc_create_args args = {
493 		.net		= clp->cl_net,
494 		.protocol	= clp->cl_proto,
495 		.address	= (struct sockaddr *)&clp->cl_addr,
496 		.addrsize	= clp->cl_addrlen,
497 		.timeout	= cl_init->timeparms,
498 		.servername	= clp->cl_hostname,
499 		.nodename	= cl_init->nodename,
500 		.program	= &nfs_program,
501 		.version	= clp->rpc_ops->version,
502 		.authflavor	= flavor,
503 	};
504 
505 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
506 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
507 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
508 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
509 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
510 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
511 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
512 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
513 
514 	if (!IS_ERR(clp->cl_rpcclient))
515 		return 0;
516 
517 	clnt = rpc_create(&args);
518 	if (IS_ERR(clnt)) {
519 		dprintk("%s: cannot create RPC client. Error = %ld\n",
520 				__func__, PTR_ERR(clnt));
521 		return PTR_ERR(clnt);
522 	}
523 
524 	clnt->cl_principal = clp->cl_principal;
525 	clp->cl_rpcclient = clnt;
526 	return 0;
527 }
528 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
529 
530 /*
531  * Version 2 or 3 client destruction
532  */
533 static void nfs_destroy_server(struct nfs_server *server)
534 {
535 	if (server->nlm_host)
536 		nlmclnt_done(server->nlm_host);
537 }
538 
539 /*
540  * Version 2 or 3 lockd setup
541  */
542 static int nfs_start_lockd(struct nfs_server *server)
543 {
544 	struct nlm_host *host;
545 	struct nfs_client *clp = server->nfs_client;
546 	struct nlmclnt_initdata nlm_init = {
547 		.hostname	= clp->cl_hostname,
548 		.address	= (struct sockaddr *)&clp->cl_addr,
549 		.addrlen	= clp->cl_addrlen,
550 		.nfs_version	= clp->rpc_ops->version,
551 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
552 					1 : 0,
553 		.net		= clp->cl_net,
554 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
555 	};
556 
557 	if (nlm_init.nfs_version > 3)
558 		return 0;
559 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
560 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
561 		return 0;
562 
563 	switch (clp->cl_proto) {
564 		default:
565 			nlm_init.protocol = IPPROTO_TCP;
566 			break;
567 		case XPRT_TRANSPORT_UDP:
568 			nlm_init.protocol = IPPROTO_UDP;
569 	}
570 
571 	host = nlmclnt_init(&nlm_init);
572 	if (IS_ERR(host))
573 		return PTR_ERR(host);
574 
575 	server->nlm_host = host;
576 	server->destroy = nfs_destroy_server;
577 	return 0;
578 }
579 
580 /*
581  * Create a general RPC client
582  */
583 int nfs_init_server_rpcclient(struct nfs_server *server,
584 		const struct rpc_timeout *timeo,
585 		rpc_authflavor_t pseudoflavour)
586 {
587 	struct nfs_client *clp = server->nfs_client;
588 
589 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
590 							pseudoflavour);
591 	if (IS_ERR(server->client)) {
592 		dprintk("%s: couldn't create rpc_client!\n", __func__);
593 		return PTR_ERR(server->client);
594 	}
595 
596 	memcpy(&server->client->cl_timeout_default,
597 			timeo,
598 			sizeof(server->client->cl_timeout_default));
599 	server->client->cl_timeout = &server->client->cl_timeout_default;
600 	server->client->cl_softrtry = 0;
601 	if (server->flags & NFS_MOUNT_SOFT)
602 		server->client->cl_softrtry = 1;
603 
604 	return 0;
605 }
606 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
607 
608 /**
609  * nfs_init_client - Initialise an NFS2 or NFS3 client
610  *
611  * @clp: nfs_client to initialise
612  * @cl_init: Initialisation parameters
613  *
614  * Returns pointer to an NFS client, or an ERR_PTR value.
615  */
616 struct nfs_client *nfs_init_client(struct nfs_client *clp,
617 				   const struct nfs_client_initdata *cl_init)
618 {
619 	int error;
620 
621 	/* the client is already initialised */
622 	if (clp->cl_cons_state == NFS_CS_READY)
623 		return clp;
624 
625 	/*
626 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
627 	 * - RFC 2623, sec 2.3.2
628 	 */
629 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
630 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
631 	if (error < 0) {
632 		nfs_put_client(clp);
633 		clp = ERR_PTR(error);
634 	}
635 	return clp;
636 }
637 EXPORT_SYMBOL_GPL(nfs_init_client);
638 
639 /*
640  * Create a version 2 or 3 client
641  */
642 static int nfs_init_server(struct nfs_server *server,
643 			   const struct nfs_parsed_mount_data *data,
644 			   struct nfs_subversion *nfs_mod)
645 {
646 	struct rpc_timeout timeparms;
647 	struct nfs_client_initdata cl_init = {
648 		.hostname = data->nfs_server.hostname,
649 		.addr = (const struct sockaddr *)&data->nfs_server.address,
650 		.addrlen = data->nfs_server.addrlen,
651 		.nfs_mod = nfs_mod,
652 		.proto = data->nfs_server.protocol,
653 		.net = data->net,
654 		.timeparms = &timeparms,
655 	};
656 	struct nfs_client *clp;
657 	int error;
658 
659 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
660 			data->timeo, data->retrans);
661 	if (data->flags & NFS_MOUNT_NORESVPORT)
662 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
663 
664 	/* Allocate or find a client reference we can use */
665 	clp = nfs_get_client(&cl_init);
666 	if (IS_ERR(clp))
667 		return PTR_ERR(clp);
668 
669 	server->nfs_client = clp;
670 
671 	/* Initialise the client representation from the mount data */
672 	server->flags = data->flags;
673 	server->options = data->options;
674 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
675 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
676 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
677 
678 	if (data->rsize)
679 		server->rsize = nfs_block_size(data->rsize, NULL);
680 	if (data->wsize)
681 		server->wsize = nfs_block_size(data->wsize, NULL);
682 
683 	server->acregmin = data->acregmin * HZ;
684 	server->acregmax = data->acregmax * HZ;
685 	server->acdirmin = data->acdirmin * HZ;
686 	server->acdirmax = data->acdirmax * HZ;
687 
688 	/* Start lockd here, before we might error out */
689 	error = nfs_start_lockd(server);
690 	if (error < 0)
691 		goto error;
692 
693 	server->port = data->nfs_server.port;
694 	server->auth_info = data->auth_info;
695 
696 	error = nfs_init_server_rpcclient(server, &timeparms,
697 					  data->selected_flavor);
698 	if (error < 0)
699 		goto error;
700 
701 	/* Preserve the values of mount_server-related mount options */
702 	if (data->mount_server.addrlen) {
703 		memcpy(&server->mountd_address, &data->mount_server.address,
704 			data->mount_server.addrlen);
705 		server->mountd_addrlen = data->mount_server.addrlen;
706 	}
707 	server->mountd_version = data->mount_server.version;
708 	server->mountd_port = data->mount_server.port;
709 	server->mountd_protocol = data->mount_server.protocol;
710 
711 	server->namelen  = data->namlen;
712 	return 0;
713 
714 error:
715 	server->nfs_client = NULL;
716 	nfs_put_client(clp);
717 	return error;
718 }
719 
720 /*
721  * Load up the server record from information gained in an fsinfo record
722  */
723 static void nfs_server_set_fsinfo(struct nfs_server *server,
724 				  struct nfs_fsinfo *fsinfo)
725 {
726 	unsigned long max_rpc_payload;
727 
728 	/* Work out a lot of parameters */
729 	if (server->rsize == 0)
730 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
731 	if (server->wsize == 0)
732 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
733 
734 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
735 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
736 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
737 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
738 
739 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
740 	if (server->rsize > max_rpc_payload)
741 		server->rsize = max_rpc_payload;
742 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
743 		server->rsize = NFS_MAX_FILE_IO_SIZE;
744 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
745 
746 	if (server->wsize > max_rpc_payload)
747 		server->wsize = max_rpc_payload;
748 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
749 		server->wsize = NFS_MAX_FILE_IO_SIZE;
750 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
751 
752 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
753 
754 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
755 	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
756 		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
757 	if (server->dtsize > server->rsize)
758 		server->dtsize = server->rsize;
759 
760 	if (server->flags & NFS_MOUNT_NOAC) {
761 		server->acregmin = server->acregmax = 0;
762 		server->acdirmin = server->acdirmax = 0;
763 	}
764 
765 	server->maxfilesize = fsinfo->maxfilesize;
766 
767 	server->time_delta = fsinfo->time_delta;
768 
769 	server->clone_blksize = fsinfo->clone_blksize;
770 	/* We're airborne Set socket buffersize */
771 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
772 }
773 
774 /*
775  * Probe filesystem information, including the FSID on v2/v3
776  */
777 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
778 {
779 	struct nfs_fsinfo fsinfo;
780 	struct nfs_client *clp = server->nfs_client;
781 	int error;
782 
783 	if (clp->rpc_ops->set_capabilities != NULL) {
784 		error = clp->rpc_ops->set_capabilities(server, mntfh);
785 		if (error < 0)
786 			return error;
787 	}
788 
789 	fsinfo.fattr = fattr;
790 	fsinfo.nlayouttypes = 0;
791 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
792 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
793 	if (error < 0)
794 		return error;
795 
796 	nfs_server_set_fsinfo(server, &fsinfo);
797 
798 	/* Get some general file system info */
799 	if (server->namelen == 0) {
800 		struct nfs_pathconf pathinfo;
801 
802 		pathinfo.fattr = fattr;
803 		nfs_fattr_init(fattr);
804 
805 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
806 			server->namelen = pathinfo.max_namelen;
807 	}
808 
809 	return 0;
810 }
811 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
812 
813 /*
814  * Copy useful information when duplicating a server record
815  */
816 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
817 {
818 	target->flags = source->flags;
819 	target->rsize = source->rsize;
820 	target->wsize = source->wsize;
821 	target->acregmin = source->acregmin;
822 	target->acregmax = source->acregmax;
823 	target->acdirmin = source->acdirmin;
824 	target->acdirmax = source->acdirmax;
825 	target->caps = source->caps;
826 	target->options = source->options;
827 	target->auth_info = source->auth_info;
828 	target->port = source->port;
829 }
830 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
831 
832 void nfs_server_insert_lists(struct nfs_server *server)
833 {
834 	struct nfs_client *clp = server->nfs_client;
835 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
836 
837 	spin_lock(&nn->nfs_client_lock);
838 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
839 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
840 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
841 	spin_unlock(&nn->nfs_client_lock);
842 
843 }
844 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
845 
846 void nfs_server_remove_lists(struct nfs_server *server)
847 {
848 	struct nfs_client *clp = server->nfs_client;
849 	struct nfs_net *nn;
850 
851 	if (clp == NULL)
852 		return;
853 	nn = net_generic(clp->cl_net, nfs_net_id);
854 	spin_lock(&nn->nfs_client_lock);
855 	list_del_rcu(&server->client_link);
856 	if (list_empty(&clp->cl_superblocks))
857 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
858 	list_del(&server->master_link);
859 	spin_unlock(&nn->nfs_client_lock);
860 
861 	synchronize_rcu();
862 }
863 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
864 
865 /*
866  * Allocate and initialise a server record
867  */
868 struct nfs_server *nfs_alloc_server(void)
869 {
870 	struct nfs_server *server;
871 
872 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
873 	if (!server)
874 		return NULL;
875 
876 	server->client = server->client_acl = ERR_PTR(-EINVAL);
877 
878 	/* Zero out the NFS state stuff */
879 	INIT_LIST_HEAD(&server->client_link);
880 	INIT_LIST_HEAD(&server->master_link);
881 	INIT_LIST_HEAD(&server->delegations);
882 	INIT_LIST_HEAD(&server->layouts);
883 	INIT_LIST_HEAD(&server->state_owners_lru);
884 	INIT_LIST_HEAD(&server->ss_copies);
885 
886 	atomic_set(&server->active, 0);
887 
888 	server->io_stats = nfs_alloc_iostats();
889 	if (!server->io_stats) {
890 		kfree(server);
891 		return NULL;
892 	}
893 
894 	ida_init(&server->openowner_id);
895 	ida_init(&server->lockowner_id);
896 	pnfs_init_server(server);
897 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
898 
899 	return server;
900 }
901 EXPORT_SYMBOL_GPL(nfs_alloc_server);
902 
903 /*
904  * Free up a server record
905  */
906 void nfs_free_server(struct nfs_server *server)
907 {
908 	nfs_server_remove_lists(server);
909 
910 	if (server->destroy != NULL)
911 		server->destroy(server);
912 
913 	if (!IS_ERR(server->client_acl))
914 		rpc_shutdown_client(server->client_acl);
915 	if (!IS_ERR(server->client))
916 		rpc_shutdown_client(server->client);
917 
918 	nfs_put_client(server->nfs_client);
919 
920 	ida_destroy(&server->lockowner_id);
921 	ida_destroy(&server->openowner_id);
922 	nfs_free_iostats(server->io_stats);
923 	kfree(server);
924 	nfs_release_automount_timer();
925 }
926 EXPORT_SYMBOL_GPL(nfs_free_server);
927 
928 /*
929  * Create a version 2 or 3 volume record
930  * - keyed on server and FSID
931  */
932 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
933 				     struct nfs_subversion *nfs_mod)
934 {
935 	struct nfs_server *server;
936 	struct nfs_fattr *fattr;
937 	int error;
938 
939 	server = nfs_alloc_server();
940 	if (!server)
941 		return ERR_PTR(-ENOMEM);
942 
943 	error = -ENOMEM;
944 	fattr = nfs_alloc_fattr();
945 	if (fattr == NULL)
946 		goto error;
947 
948 	/* Get a client representation */
949 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
950 	if (error < 0)
951 		goto error;
952 
953 	/* Probe the root fh to retrieve its FSID */
954 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
955 	if (error < 0)
956 		goto error;
957 	if (server->nfs_client->rpc_ops->version == 3) {
958 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
959 			server->namelen = NFS3_MAXNAMLEN;
960 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
961 			server->caps |= NFS_CAP_READDIRPLUS;
962 	} else {
963 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
964 			server->namelen = NFS2_MAXNAMLEN;
965 	}
966 
967 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
968 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh,
969 				fattr, NULL, NULL);
970 		if (error < 0) {
971 			dprintk("nfs_create_server: getattr error = %d\n", -error);
972 			goto error;
973 		}
974 	}
975 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
976 
977 	dprintk("Server FSID: %llx:%llx\n",
978 		(unsigned long long) server->fsid.major,
979 		(unsigned long long) server->fsid.minor);
980 
981 	nfs_server_insert_lists(server);
982 	server->mount_time = jiffies;
983 	nfs_free_fattr(fattr);
984 	return server;
985 
986 error:
987 	nfs_free_fattr(fattr);
988 	nfs_free_server(server);
989 	return ERR_PTR(error);
990 }
991 EXPORT_SYMBOL_GPL(nfs_create_server);
992 
993 /*
994  * Clone an NFS2, NFS3 or NFS4 server record
995  */
996 struct nfs_server *nfs_clone_server(struct nfs_server *source,
997 				    struct nfs_fh *fh,
998 				    struct nfs_fattr *fattr,
999 				    rpc_authflavor_t flavor)
1000 {
1001 	struct nfs_server *server;
1002 	struct nfs_fattr *fattr_fsinfo;
1003 	int error;
1004 
1005 	server = nfs_alloc_server();
1006 	if (!server)
1007 		return ERR_PTR(-ENOMEM);
1008 
1009 	error = -ENOMEM;
1010 	fattr_fsinfo = nfs_alloc_fattr();
1011 	if (fattr_fsinfo == NULL)
1012 		goto out_free_server;
1013 
1014 	/* Copy data from the source */
1015 	server->nfs_client = source->nfs_client;
1016 	server->destroy = source->destroy;
1017 	refcount_inc(&server->nfs_client->cl_count);
1018 	nfs_server_copy_userdata(server, source);
1019 
1020 	server->fsid = fattr->fsid;
1021 
1022 	error = nfs_init_server_rpcclient(server,
1023 			source->client->cl_timeout,
1024 			flavor);
1025 	if (error < 0)
1026 		goto out_free_server;
1027 
1028 	/* probe the filesystem info for this server filesystem */
1029 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1030 	if (error < 0)
1031 		goto out_free_server;
1032 
1033 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1034 		server->namelen = NFS4_MAXNAMLEN;
1035 
1036 	error = nfs_start_lockd(server);
1037 	if (error < 0)
1038 		goto out_free_server;
1039 
1040 	nfs_server_insert_lists(server);
1041 	server->mount_time = jiffies;
1042 
1043 	nfs_free_fattr(fattr_fsinfo);
1044 	return server;
1045 
1046 out_free_server:
1047 	nfs_free_fattr(fattr_fsinfo);
1048 	nfs_free_server(server);
1049 	return ERR_PTR(error);
1050 }
1051 EXPORT_SYMBOL_GPL(nfs_clone_server);
1052 
1053 void nfs_clients_init(struct net *net)
1054 {
1055 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1056 
1057 	INIT_LIST_HEAD(&nn->nfs_client_list);
1058 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1059 #if IS_ENABLED(CONFIG_NFS_V4)
1060 	idr_init(&nn->cb_ident_idr);
1061 #endif
1062 	spin_lock_init(&nn->nfs_client_lock);
1063 	nn->boot_time = ktime_get_real();
1064 }
1065 
1066 #ifdef CONFIG_PROC_FS
1067 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1068 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1069 static void nfs_server_list_stop(struct seq_file *p, void *v);
1070 static int nfs_server_list_show(struct seq_file *m, void *v);
1071 
1072 static const struct seq_operations nfs_server_list_ops = {
1073 	.start	= nfs_server_list_start,
1074 	.next	= nfs_server_list_next,
1075 	.stop	= nfs_server_list_stop,
1076 	.show	= nfs_server_list_show,
1077 };
1078 
1079 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1080 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1081 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1082 static int nfs_volume_list_show(struct seq_file *m, void *v);
1083 
1084 static const struct seq_operations nfs_volume_list_ops = {
1085 	.start	= nfs_volume_list_start,
1086 	.next	= nfs_volume_list_next,
1087 	.stop	= nfs_volume_list_stop,
1088 	.show	= nfs_volume_list_show,
1089 };
1090 
1091 /*
1092  * set up the iterator to start reading from the server list and return the first item
1093  */
1094 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1095 				__acquires(&nn->nfs_client_lock)
1096 {
1097 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1098 
1099 	/* lock the list against modification */
1100 	spin_lock(&nn->nfs_client_lock);
1101 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1102 }
1103 
1104 /*
1105  * move to next server
1106  */
1107 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1108 {
1109 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1110 
1111 	return seq_list_next(v, &nn->nfs_client_list, pos);
1112 }
1113 
1114 /*
1115  * clean up after reading from the transports list
1116  */
1117 static void nfs_server_list_stop(struct seq_file *p, void *v)
1118 				__releases(&nn->nfs_client_lock)
1119 {
1120 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1121 
1122 	spin_unlock(&nn->nfs_client_lock);
1123 }
1124 
1125 /*
1126  * display a header line followed by a load of call lines
1127  */
1128 static int nfs_server_list_show(struct seq_file *m, void *v)
1129 {
1130 	struct nfs_client *clp;
1131 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1132 
1133 	/* display header on line 1 */
1134 	if (v == &nn->nfs_client_list) {
1135 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1136 		return 0;
1137 	}
1138 
1139 	/* display one transport per line on subsequent lines */
1140 	clp = list_entry(v, struct nfs_client, cl_share_link);
1141 
1142 	/* Check if the client is initialized */
1143 	if (clp->cl_cons_state != NFS_CS_READY)
1144 		return 0;
1145 
1146 	rcu_read_lock();
1147 	seq_printf(m, "v%u %s %s %3d %s\n",
1148 		   clp->rpc_ops->version,
1149 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1150 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1151 		   refcount_read(&clp->cl_count),
1152 		   clp->cl_hostname);
1153 	rcu_read_unlock();
1154 
1155 	return 0;
1156 }
1157 
1158 /*
1159  * set up the iterator to start reading from the volume list and return the first item
1160  */
1161 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1162 				__acquires(&nn->nfs_client_lock)
1163 {
1164 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1165 
1166 	/* lock the list against modification */
1167 	spin_lock(&nn->nfs_client_lock);
1168 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1169 }
1170 
1171 /*
1172  * move to next volume
1173  */
1174 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1175 {
1176 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1177 
1178 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1179 }
1180 
1181 /*
1182  * clean up after reading from the transports list
1183  */
1184 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1185 				__releases(&nn->nfs_client_lock)
1186 {
1187 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1188 
1189 	spin_unlock(&nn->nfs_client_lock);
1190 }
1191 
1192 /*
1193  * display a header line followed by a load of call lines
1194  */
1195 static int nfs_volume_list_show(struct seq_file *m, void *v)
1196 {
1197 	struct nfs_server *server;
1198 	struct nfs_client *clp;
1199 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1200 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1201 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1202 
1203 	/* display header on line 1 */
1204 	if (v == &nn->nfs_volume_list) {
1205 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1206 			    "                              FSC\n");
1207 		return 0;
1208 	}
1209 	/* display one transport per line on subsequent lines */
1210 	server = list_entry(v, struct nfs_server, master_link);
1211 	clp = server->nfs_client;
1212 
1213 	snprintf(dev, sizeof(dev), "%u:%u",
1214 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1215 
1216 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1217 		 (unsigned long long) server->fsid.major,
1218 		 (unsigned long long) server->fsid.minor);
1219 
1220 	rcu_read_lock();
1221 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1222 		   clp->rpc_ops->version,
1223 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1224 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1225 		   dev,
1226 		   fsid,
1227 		   nfs_server_fscache_state(server));
1228 	rcu_read_unlock();
1229 
1230 	return 0;
1231 }
1232 
1233 int nfs_fs_proc_net_init(struct net *net)
1234 {
1235 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1236 	struct proc_dir_entry *p;
1237 
1238 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1239 	if (!nn->proc_nfsfs)
1240 		goto error_0;
1241 
1242 	/* a file of servers with which we're dealing */
1243 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1244 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1245 	if (!p)
1246 		goto error_1;
1247 
1248 	/* a file of volumes that we have mounted */
1249 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1250 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1251 	if (!p)
1252 		goto error_1;
1253 	return 0;
1254 
1255 error_1:
1256 	remove_proc_subtree("nfsfs", net->proc_net);
1257 error_0:
1258 	return -ENOMEM;
1259 }
1260 
1261 void nfs_fs_proc_net_exit(struct net *net)
1262 {
1263 	remove_proc_subtree("nfsfs", net->proc_net);
1264 }
1265 
1266 /*
1267  * initialise the /proc/fs/nfsfs/ directory
1268  */
1269 int __init nfs_fs_proc_init(void)
1270 {
1271 	if (!proc_mkdir("fs/nfsfs", NULL))
1272 		goto error_0;
1273 
1274 	/* a file of servers with which we're dealing */
1275 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1276 		goto error_1;
1277 
1278 	/* a file of volumes that we have mounted */
1279 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1280 		goto error_1;
1281 
1282 	return 0;
1283 error_1:
1284 	remove_proc_subtree("fs/nfsfs", NULL);
1285 error_0:
1286 	return -ENOMEM;
1287 }
1288 
1289 /*
1290  * clean up the /proc/fs/nfsfs/ directory
1291  */
1292 void nfs_fs_proc_exit(void)
1293 {
1294 	remove_proc_subtree("fs/nfsfs", NULL);
1295 }
1296 
1297 #endif /* CONFIG_PROC_FS */
1298