xref: /linux/fs/nfs/client.c (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
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 	struct rpc_cred *cred;
155 	int err = -ENOMEM;
156 
157 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
158 		goto error_0;
159 
160 	clp->cl_nfs_mod = cl_init->nfs_mod;
161 	if (!try_module_get(clp->cl_nfs_mod->owner))
162 		goto error_dealloc;
163 
164 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
165 
166 	refcount_set(&clp->cl_count, 1);
167 	clp->cl_cons_state = NFS_CS_INITING;
168 
169 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
170 	clp->cl_addrlen = cl_init->addrlen;
171 
172 	if (cl_init->hostname) {
173 		err = -ENOMEM;
174 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
175 		if (!clp->cl_hostname)
176 			goto error_cleanup;
177 	}
178 
179 	INIT_LIST_HEAD(&clp->cl_superblocks);
180 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
181 
182 	clp->cl_proto = cl_init->proto;
183 	clp->cl_net = get_net(cl_init->net);
184 
185 	cred = rpc_lookup_machine_cred("*");
186 	if (!IS_ERR(cred))
187 		clp->cl_machine_cred = cred;
188 	nfs_fscache_get_client_cookie(clp);
189 
190 	return clp;
191 
192 error_cleanup:
193 	put_nfs_version(clp->cl_nfs_mod);
194 error_dealloc:
195 	kfree(clp);
196 error_0:
197 	return ERR_PTR(err);
198 }
199 EXPORT_SYMBOL_GPL(nfs_alloc_client);
200 
201 #if IS_ENABLED(CONFIG_NFS_V4)
202 void nfs_cleanup_cb_ident_idr(struct net *net)
203 {
204 	struct nfs_net *nn = net_generic(net, nfs_net_id);
205 
206 	idr_destroy(&nn->cb_ident_idr);
207 }
208 
209 /* nfs_client_lock held */
210 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
211 {
212 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
213 
214 	if (clp->cl_cb_ident)
215 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
216 }
217 
218 static void pnfs_init_server(struct nfs_server *server)
219 {
220 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
221 }
222 
223 #else
224 void nfs_cleanup_cb_ident_idr(struct net *net)
225 {
226 }
227 
228 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
229 {
230 }
231 
232 static void pnfs_init_server(struct nfs_server *server)
233 {
234 }
235 
236 #endif /* CONFIG_NFS_V4 */
237 
238 /*
239  * Destroy a shared client record
240  */
241 void nfs_free_client(struct nfs_client *clp)
242 {
243 	nfs_fscache_release_client_cookie(clp);
244 
245 	/* -EIO all pending I/O */
246 	if (!IS_ERR(clp->cl_rpcclient))
247 		rpc_shutdown_client(clp->cl_rpcclient);
248 
249 	if (clp->cl_machine_cred != NULL)
250 		put_rpccred(clp->cl_machine_cred);
251 
252 	put_net(clp->cl_net);
253 	put_nfs_version(clp->cl_nfs_mod);
254 	kfree(clp->cl_hostname);
255 	kfree(clp->cl_acceptor);
256 	kfree(clp);
257 }
258 EXPORT_SYMBOL_GPL(nfs_free_client);
259 
260 /*
261  * Release a reference to a shared client record
262  */
263 void nfs_put_client(struct nfs_client *clp)
264 {
265 	struct nfs_net *nn;
266 
267 	if (!clp)
268 		return;
269 
270 	nn = net_generic(clp->cl_net, nfs_net_id);
271 
272 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
273 		list_del(&clp->cl_share_link);
274 		nfs_cb_idr_remove_locked(clp);
275 		spin_unlock(&nn->nfs_client_lock);
276 
277 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
278 
279 		clp->rpc_ops->free_client(clp);
280 	}
281 }
282 EXPORT_SYMBOL_GPL(nfs_put_client);
283 
284 /*
285  * Find an nfs_client on the list that matches the initialisation data
286  * that is supplied.
287  */
288 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
289 {
290 	struct nfs_client *clp;
291 	const struct sockaddr *sap = data->addr;
292 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
293 
294 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
295 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
296 		/* Don't match clients that failed to initialise properly */
297 		if (clp->cl_cons_state < 0)
298 			continue;
299 
300 		/* Different NFS versions cannot share the same nfs_client */
301 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
302 			continue;
303 
304 		if (clp->cl_proto != data->proto)
305 			continue;
306 		/* Match nfsv4 minorversion */
307 		if (clp->cl_minorversion != data->minorversion)
308 			continue;
309 		/* Match the full socket address */
310 		if (!rpc_cmp_addr_port(sap, clap))
311 			/* Match all xprt_switch full socket addresses */
312 			if (IS_ERR(clp->cl_rpcclient) ||
313                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
314 							   sap))
315 				continue;
316 
317 		refcount_inc(&clp->cl_count);
318 		return clp;
319 	}
320 	return NULL;
321 }
322 
323 /*
324  * Return true if @clp is done initializing, false if still working on it.
325  *
326  * Use nfs_client_init_status to check if it was successful.
327  */
328 bool nfs_client_init_is_complete(const struct nfs_client *clp)
329 {
330 	return clp->cl_cons_state <= NFS_CS_READY;
331 }
332 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
333 
334 /*
335  * Return 0 if @clp was successfully initialized, -errno otherwise.
336  *
337  * This must be called *after* nfs_client_init_is_complete() returns true,
338  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
339  */
340 int nfs_client_init_status(const struct nfs_client *clp)
341 {
342 	/* called without checking nfs_client_init_is_complete */
343 	if (clp->cl_cons_state > NFS_CS_READY) {
344 		WARN_ON_ONCE(1);
345 		return -EINVAL;
346 	}
347 	return clp->cl_cons_state;
348 }
349 EXPORT_SYMBOL_GPL(nfs_client_init_status);
350 
351 int nfs_wait_client_init_complete(const struct nfs_client *clp)
352 {
353 	return wait_event_killable(nfs_client_active_wq,
354 			nfs_client_init_is_complete(clp));
355 }
356 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
357 
358 /*
359  * Found an existing client.  Make sure it's ready before returning.
360  */
361 static struct nfs_client *
362 nfs_found_client(const struct nfs_client_initdata *cl_init,
363 		 struct nfs_client *clp)
364 {
365 	int error;
366 
367 	error = nfs_wait_client_init_complete(clp);
368 	if (error < 0) {
369 		nfs_put_client(clp);
370 		return ERR_PTR(-ERESTARTSYS);
371 	}
372 
373 	if (clp->cl_cons_state < NFS_CS_READY) {
374 		error = clp->cl_cons_state;
375 		nfs_put_client(clp);
376 		return ERR_PTR(error);
377 	}
378 
379 	smp_rmb();
380 	return clp;
381 }
382 
383 /*
384  * Look up a client by IP address and protocol version
385  * - creates a new record if one doesn't yet exist
386  */
387 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
388 {
389 	struct nfs_client *clp, *new = NULL;
390 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
391 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
392 
393 	if (cl_init->hostname == NULL) {
394 		WARN_ON(1);
395 		return NULL;
396 	}
397 
398 	/* see if the client already exists */
399 	do {
400 		spin_lock(&nn->nfs_client_lock);
401 
402 		clp = nfs_match_client(cl_init);
403 		if (clp) {
404 			spin_unlock(&nn->nfs_client_lock);
405 			if (new)
406 				new->rpc_ops->free_client(new);
407 			return nfs_found_client(cl_init, clp);
408 		}
409 		if (new) {
410 			list_add_tail(&new->cl_share_link,
411 					&nn->nfs_client_list);
412 			spin_unlock(&nn->nfs_client_lock);
413 			new->cl_flags = cl_init->init_flags;
414 			return rpc_ops->init_client(new, cl_init);
415 		}
416 
417 		spin_unlock(&nn->nfs_client_lock);
418 
419 		new = rpc_ops->alloc_client(cl_init);
420 	} while (!IS_ERR(new));
421 
422 	return new;
423 }
424 EXPORT_SYMBOL_GPL(nfs_get_client);
425 
426 /*
427  * Mark a server as ready or failed
428  */
429 void nfs_mark_client_ready(struct nfs_client *clp, int state)
430 {
431 	smp_wmb();
432 	clp->cl_cons_state = state;
433 	wake_up_all(&nfs_client_active_wq);
434 }
435 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
436 
437 /*
438  * Initialise the timeout values for a connection
439  */
440 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
441 				    int timeo, int retrans)
442 {
443 	to->to_initval = timeo * HZ / 10;
444 	to->to_retries = retrans;
445 
446 	switch (proto) {
447 	case XPRT_TRANSPORT_TCP:
448 	case XPRT_TRANSPORT_RDMA:
449 		if (retrans == NFS_UNSPEC_RETRANS)
450 			to->to_retries = NFS_DEF_TCP_RETRANS;
451 		if (timeo == NFS_UNSPEC_TIMEO || to->to_retries == 0)
452 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
453 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
454 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
455 		to->to_increment = to->to_initval;
456 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
457 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
458 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
459 		if (to->to_maxval < to->to_initval)
460 			to->to_maxval = to->to_initval;
461 		to->to_exponential = 0;
462 		break;
463 	case XPRT_TRANSPORT_UDP:
464 		if (retrans == NFS_UNSPEC_RETRANS)
465 			to->to_retries = NFS_DEF_UDP_RETRANS;
466 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
467 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
468 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
469 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
470 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
471 		to->to_exponential = 1;
472 		break;
473 	default:
474 		BUG();
475 	}
476 }
477 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
478 
479 /*
480  * Create an RPC client handle
481  */
482 int nfs_create_rpc_client(struct nfs_client *clp,
483 			  const struct nfs_client_initdata *cl_init,
484 			  rpc_authflavor_t flavor)
485 {
486 	struct rpc_clnt		*clnt = NULL;
487 	struct rpc_create_args args = {
488 		.net		= clp->cl_net,
489 		.protocol	= clp->cl_proto,
490 		.address	= (struct sockaddr *)&clp->cl_addr,
491 		.addrsize	= clp->cl_addrlen,
492 		.timeout	= cl_init->timeparms,
493 		.servername	= clp->cl_hostname,
494 		.nodename	= cl_init->nodename,
495 		.program	= &nfs_program,
496 		.version	= clp->rpc_ops->version,
497 		.authflavor	= flavor,
498 	};
499 
500 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
501 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
502 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
503 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
504 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
505 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
506 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
507 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
508 
509 	if (!IS_ERR(clp->cl_rpcclient))
510 		return 0;
511 
512 	clnt = rpc_create(&args);
513 	if (IS_ERR(clnt)) {
514 		dprintk("%s: cannot create RPC client. Error = %ld\n",
515 				__func__, PTR_ERR(clnt));
516 		return PTR_ERR(clnt);
517 	}
518 
519 	clp->cl_rpcclient = clnt;
520 	return 0;
521 }
522 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
523 
524 /*
525  * Version 2 or 3 client destruction
526  */
527 static void nfs_destroy_server(struct nfs_server *server)
528 {
529 	if (server->nlm_host)
530 		nlmclnt_done(server->nlm_host);
531 }
532 
533 /*
534  * Version 2 or 3 lockd setup
535  */
536 static int nfs_start_lockd(struct nfs_server *server)
537 {
538 	struct nlm_host *host;
539 	struct nfs_client *clp = server->nfs_client;
540 	struct nlmclnt_initdata nlm_init = {
541 		.hostname	= clp->cl_hostname,
542 		.address	= (struct sockaddr *)&clp->cl_addr,
543 		.addrlen	= clp->cl_addrlen,
544 		.nfs_version	= clp->rpc_ops->version,
545 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
546 					1 : 0,
547 		.net		= clp->cl_net,
548 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
549 	};
550 
551 	if (nlm_init.nfs_version > 3)
552 		return 0;
553 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
554 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
555 		return 0;
556 
557 	switch (clp->cl_proto) {
558 		default:
559 			nlm_init.protocol = IPPROTO_TCP;
560 			break;
561 		case XPRT_TRANSPORT_UDP:
562 			nlm_init.protocol = IPPROTO_UDP;
563 	}
564 
565 	host = nlmclnt_init(&nlm_init);
566 	if (IS_ERR(host))
567 		return PTR_ERR(host);
568 
569 	server->nlm_host = host;
570 	server->destroy = nfs_destroy_server;
571 	return 0;
572 }
573 
574 /*
575  * Create a general RPC client
576  */
577 int nfs_init_server_rpcclient(struct nfs_server *server,
578 		const struct rpc_timeout *timeo,
579 		rpc_authflavor_t pseudoflavour)
580 {
581 	struct nfs_client *clp = server->nfs_client;
582 
583 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
584 							pseudoflavour);
585 	if (IS_ERR(server->client)) {
586 		dprintk("%s: couldn't create rpc_client!\n", __func__);
587 		return PTR_ERR(server->client);
588 	}
589 
590 	memcpy(&server->client->cl_timeout_default,
591 			timeo,
592 			sizeof(server->client->cl_timeout_default));
593 	server->client->cl_timeout = &server->client->cl_timeout_default;
594 	server->client->cl_softrtry = 0;
595 	if (server->flags & NFS_MOUNT_SOFT)
596 		server->client->cl_softrtry = 1;
597 
598 	return 0;
599 }
600 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
601 
602 /**
603  * nfs_init_client - Initialise an NFS2 or NFS3 client
604  *
605  * @clp: nfs_client to initialise
606  * @cl_init: Initialisation parameters
607  *
608  * Returns pointer to an NFS client, or an ERR_PTR value.
609  */
610 struct nfs_client *nfs_init_client(struct nfs_client *clp,
611 				   const struct nfs_client_initdata *cl_init)
612 {
613 	int error;
614 
615 	/* the client is already initialised */
616 	if (clp->cl_cons_state == NFS_CS_READY)
617 		return clp;
618 
619 	/*
620 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
621 	 * - RFC 2623, sec 2.3.2
622 	 */
623 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
624 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
625 	if (error < 0) {
626 		nfs_put_client(clp);
627 		clp = ERR_PTR(error);
628 	}
629 	return clp;
630 }
631 EXPORT_SYMBOL_GPL(nfs_init_client);
632 
633 /*
634  * Create a version 2 or 3 client
635  */
636 static int nfs_init_server(struct nfs_server *server,
637 			   const struct nfs_parsed_mount_data *data,
638 			   struct nfs_subversion *nfs_mod)
639 {
640 	struct rpc_timeout timeparms;
641 	struct nfs_client_initdata cl_init = {
642 		.hostname = data->nfs_server.hostname,
643 		.addr = (const struct sockaddr *)&data->nfs_server.address,
644 		.addrlen = data->nfs_server.addrlen,
645 		.nfs_mod = nfs_mod,
646 		.proto = data->nfs_server.protocol,
647 		.net = data->net,
648 		.timeparms = &timeparms,
649 	};
650 	struct nfs_client *clp;
651 	int error;
652 
653 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
654 			data->timeo, data->retrans);
655 	if (data->flags & NFS_MOUNT_NORESVPORT)
656 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
657 
658 	/* Allocate or find a client reference we can use */
659 	clp = nfs_get_client(&cl_init);
660 	if (IS_ERR(clp))
661 		return PTR_ERR(clp);
662 
663 	server->nfs_client = clp;
664 
665 	/* Initialise the client representation from the mount data */
666 	server->flags = data->flags;
667 	server->options = data->options;
668 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
669 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
670 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
671 
672 	if (data->rsize)
673 		server->rsize = nfs_block_size(data->rsize, NULL);
674 	if (data->wsize)
675 		server->wsize = nfs_block_size(data->wsize, NULL);
676 
677 	server->acregmin = data->acregmin * HZ;
678 	server->acregmax = data->acregmax * HZ;
679 	server->acdirmin = data->acdirmin * HZ;
680 	server->acdirmax = data->acdirmax * HZ;
681 
682 	/* Start lockd here, before we might error out */
683 	error = nfs_start_lockd(server);
684 	if (error < 0)
685 		goto error;
686 
687 	server->port = data->nfs_server.port;
688 	server->auth_info = data->auth_info;
689 
690 	error = nfs_init_server_rpcclient(server, &timeparms,
691 					  data->selected_flavor);
692 	if (error < 0)
693 		goto error;
694 
695 	/* Preserve the values of mount_server-related mount options */
696 	if (data->mount_server.addrlen) {
697 		memcpy(&server->mountd_address, &data->mount_server.address,
698 			data->mount_server.addrlen);
699 		server->mountd_addrlen = data->mount_server.addrlen;
700 	}
701 	server->mountd_version = data->mount_server.version;
702 	server->mountd_port = data->mount_server.port;
703 	server->mountd_protocol = data->mount_server.protocol;
704 
705 	server->namelen  = data->namlen;
706 	return 0;
707 
708 error:
709 	server->nfs_client = NULL;
710 	nfs_put_client(clp);
711 	return error;
712 }
713 
714 /*
715  * Load up the server record from information gained in an fsinfo record
716  */
717 static void nfs_server_set_fsinfo(struct nfs_server *server,
718 				  struct nfs_fsinfo *fsinfo)
719 {
720 	unsigned long max_rpc_payload;
721 
722 	/* Work out a lot of parameters */
723 	if (server->rsize == 0)
724 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
725 	if (server->wsize == 0)
726 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
727 
728 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
729 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
730 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
731 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
732 
733 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
734 	if (server->rsize > max_rpc_payload)
735 		server->rsize = max_rpc_payload;
736 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
737 		server->rsize = NFS_MAX_FILE_IO_SIZE;
738 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
739 
740 	if (server->wsize > max_rpc_payload)
741 		server->wsize = max_rpc_payload;
742 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
743 		server->wsize = NFS_MAX_FILE_IO_SIZE;
744 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
745 
746 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
747 
748 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
749 	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
750 		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
751 	if (server->dtsize > server->rsize)
752 		server->dtsize = server->rsize;
753 
754 	if (server->flags & NFS_MOUNT_NOAC) {
755 		server->acregmin = server->acregmax = 0;
756 		server->acdirmin = server->acdirmax = 0;
757 	}
758 
759 	server->maxfilesize = fsinfo->maxfilesize;
760 
761 	server->time_delta = fsinfo->time_delta;
762 
763 	server->clone_blksize = fsinfo->clone_blksize;
764 	/* We're airborne Set socket buffersize */
765 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
766 }
767 
768 /*
769  * Probe filesystem information, including the FSID on v2/v3
770  */
771 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
772 {
773 	struct nfs_fsinfo fsinfo;
774 	struct nfs_client *clp = server->nfs_client;
775 	int error;
776 
777 	if (clp->rpc_ops->set_capabilities != NULL) {
778 		error = clp->rpc_ops->set_capabilities(server, mntfh);
779 		if (error < 0)
780 			return error;
781 	}
782 
783 	fsinfo.fattr = fattr;
784 	fsinfo.nlayouttypes = 0;
785 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
786 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
787 	if (error < 0)
788 		return error;
789 
790 	nfs_server_set_fsinfo(server, &fsinfo);
791 
792 	/* Get some general file system info */
793 	if (server->namelen == 0) {
794 		struct nfs_pathconf pathinfo;
795 
796 		pathinfo.fattr = fattr;
797 		nfs_fattr_init(fattr);
798 
799 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
800 			server->namelen = pathinfo.max_namelen;
801 	}
802 
803 	return 0;
804 }
805 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
806 
807 /*
808  * Copy useful information when duplicating a server record
809  */
810 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
811 {
812 	target->flags = source->flags;
813 	target->rsize = source->rsize;
814 	target->wsize = source->wsize;
815 	target->acregmin = source->acregmin;
816 	target->acregmax = source->acregmax;
817 	target->acdirmin = source->acdirmin;
818 	target->acdirmax = source->acdirmax;
819 	target->caps = source->caps;
820 	target->options = source->options;
821 	target->auth_info = source->auth_info;
822 	target->port = source->port;
823 }
824 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
825 
826 void nfs_server_insert_lists(struct nfs_server *server)
827 {
828 	struct nfs_client *clp = server->nfs_client;
829 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
830 
831 	spin_lock(&nn->nfs_client_lock);
832 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
833 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
834 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
835 	spin_unlock(&nn->nfs_client_lock);
836 
837 }
838 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
839 
840 void nfs_server_remove_lists(struct nfs_server *server)
841 {
842 	struct nfs_client *clp = server->nfs_client;
843 	struct nfs_net *nn;
844 
845 	if (clp == NULL)
846 		return;
847 	nn = net_generic(clp->cl_net, nfs_net_id);
848 	spin_lock(&nn->nfs_client_lock);
849 	list_del_rcu(&server->client_link);
850 	if (list_empty(&clp->cl_superblocks))
851 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
852 	list_del(&server->master_link);
853 	spin_unlock(&nn->nfs_client_lock);
854 
855 	synchronize_rcu();
856 }
857 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
858 
859 /*
860  * Allocate and initialise a server record
861  */
862 struct nfs_server *nfs_alloc_server(void)
863 {
864 	struct nfs_server *server;
865 
866 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
867 	if (!server)
868 		return NULL;
869 
870 	server->client = server->client_acl = ERR_PTR(-EINVAL);
871 
872 	/* Zero out the NFS state stuff */
873 	INIT_LIST_HEAD(&server->client_link);
874 	INIT_LIST_HEAD(&server->master_link);
875 	INIT_LIST_HEAD(&server->delegations);
876 	INIT_LIST_HEAD(&server->layouts);
877 	INIT_LIST_HEAD(&server->state_owners_lru);
878 
879 	atomic_set(&server->active, 0);
880 
881 	server->io_stats = nfs_alloc_iostats();
882 	if (!server->io_stats) {
883 		kfree(server);
884 		return NULL;
885 	}
886 
887 	ida_init(&server->openowner_id);
888 	ida_init(&server->lockowner_id);
889 	pnfs_init_server(server);
890 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
891 
892 	return server;
893 }
894 EXPORT_SYMBOL_GPL(nfs_alloc_server);
895 
896 /*
897  * Free up a server record
898  */
899 void nfs_free_server(struct nfs_server *server)
900 {
901 	nfs_server_remove_lists(server);
902 
903 	if (server->destroy != NULL)
904 		server->destroy(server);
905 
906 	if (!IS_ERR(server->client_acl))
907 		rpc_shutdown_client(server->client_acl);
908 	if (!IS_ERR(server->client))
909 		rpc_shutdown_client(server->client);
910 
911 	nfs_put_client(server->nfs_client);
912 
913 	ida_destroy(&server->lockowner_id);
914 	ida_destroy(&server->openowner_id);
915 	nfs_free_iostats(server->io_stats);
916 	kfree(server);
917 	nfs_release_automount_timer();
918 }
919 EXPORT_SYMBOL_GPL(nfs_free_server);
920 
921 /*
922  * Create a version 2 or 3 volume record
923  * - keyed on server and FSID
924  */
925 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
926 				     struct nfs_subversion *nfs_mod)
927 {
928 	struct nfs_server *server;
929 	struct nfs_fattr *fattr;
930 	int error;
931 
932 	server = nfs_alloc_server();
933 	if (!server)
934 		return ERR_PTR(-ENOMEM);
935 
936 	error = -ENOMEM;
937 	fattr = nfs_alloc_fattr();
938 	if (fattr == NULL)
939 		goto error;
940 
941 	/* Get a client representation */
942 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
943 	if (error < 0)
944 		goto error;
945 
946 	/* Probe the root fh to retrieve its FSID */
947 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
948 	if (error < 0)
949 		goto error;
950 	if (server->nfs_client->rpc_ops->version == 3) {
951 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
952 			server->namelen = NFS3_MAXNAMLEN;
953 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
954 			server->caps |= NFS_CAP_READDIRPLUS;
955 	} else {
956 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
957 			server->namelen = NFS2_MAXNAMLEN;
958 	}
959 
960 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
961 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh, fattr, NULL);
962 		if (error < 0) {
963 			dprintk("nfs_create_server: getattr error = %d\n", -error);
964 			goto error;
965 		}
966 	}
967 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
968 
969 	dprintk("Server FSID: %llx:%llx\n",
970 		(unsigned long long) server->fsid.major,
971 		(unsigned long long) server->fsid.minor);
972 
973 	nfs_server_insert_lists(server);
974 	server->mount_time = jiffies;
975 	nfs_free_fattr(fattr);
976 	return server;
977 
978 error:
979 	nfs_free_fattr(fattr);
980 	nfs_free_server(server);
981 	return ERR_PTR(error);
982 }
983 EXPORT_SYMBOL_GPL(nfs_create_server);
984 
985 /*
986  * Clone an NFS2, NFS3 or NFS4 server record
987  */
988 struct nfs_server *nfs_clone_server(struct nfs_server *source,
989 				    struct nfs_fh *fh,
990 				    struct nfs_fattr *fattr,
991 				    rpc_authflavor_t flavor)
992 {
993 	struct nfs_server *server;
994 	struct nfs_fattr *fattr_fsinfo;
995 	int error;
996 
997 	server = nfs_alloc_server();
998 	if (!server)
999 		return ERR_PTR(-ENOMEM);
1000 
1001 	error = -ENOMEM;
1002 	fattr_fsinfo = nfs_alloc_fattr();
1003 	if (fattr_fsinfo == NULL)
1004 		goto out_free_server;
1005 
1006 	/* Copy data from the source */
1007 	server->nfs_client = source->nfs_client;
1008 	server->destroy = source->destroy;
1009 	refcount_inc(&server->nfs_client->cl_count);
1010 	nfs_server_copy_userdata(server, source);
1011 
1012 	server->fsid = fattr->fsid;
1013 
1014 	error = nfs_init_server_rpcclient(server,
1015 			source->client->cl_timeout,
1016 			flavor);
1017 	if (error < 0)
1018 		goto out_free_server;
1019 
1020 	/* probe the filesystem info for this server filesystem */
1021 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1022 	if (error < 0)
1023 		goto out_free_server;
1024 
1025 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1026 		server->namelen = NFS4_MAXNAMLEN;
1027 
1028 	error = nfs_start_lockd(server);
1029 	if (error < 0)
1030 		goto out_free_server;
1031 
1032 	nfs_server_insert_lists(server);
1033 	server->mount_time = jiffies;
1034 
1035 	nfs_free_fattr(fattr_fsinfo);
1036 	return server;
1037 
1038 out_free_server:
1039 	nfs_free_fattr(fattr_fsinfo);
1040 	nfs_free_server(server);
1041 	return ERR_PTR(error);
1042 }
1043 EXPORT_SYMBOL_GPL(nfs_clone_server);
1044 
1045 void nfs_clients_init(struct net *net)
1046 {
1047 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1048 
1049 	INIT_LIST_HEAD(&nn->nfs_client_list);
1050 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1051 #if IS_ENABLED(CONFIG_NFS_V4)
1052 	idr_init(&nn->cb_ident_idr);
1053 #endif
1054 	spin_lock_init(&nn->nfs_client_lock);
1055 	nn->boot_time = ktime_get_real();
1056 }
1057 
1058 #ifdef CONFIG_PROC_FS
1059 static int nfs_server_list_open(struct inode *inode, struct file *file);
1060 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1061 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1062 static void nfs_server_list_stop(struct seq_file *p, void *v);
1063 static int nfs_server_list_show(struct seq_file *m, void *v);
1064 
1065 static const struct seq_operations nfs_server_list_ops = {
1066 	.start	= nfs_server_list_start,
1067 	.next	= nfs_server_list_next,
1068 	.stop	= nfs_server_list_stop,
1069 	.show	= nfs_server_list_show,
1070 };
1071 
1072 static const struct file_operations nfs_server_list_fops = {
1073 	.open		= nfs_server_list_open,
1074 	.read		= seq_read,
1075 	.llseek		= seq_lseek,
1076 	.release	= seq_release_net,
1077 };
1078 
1079 static int nfs_volume_list_open(struct inode *inode, struct file *file);
1080 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1081 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1082 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1083 static int nfs_volume_list_show(struct seq_file *m, void *v);
1084 
1085 static const struct seq_operations nfs_volume_list_ops = {
1086 	.start	= nfs_volume_list_start,
1087 	.next	= nfs_volume_list_next,
1088 	.stop	= nfs_volume_list_stop,
1089 	.show	= nfs_volume_list_show,
1090 };
1091 
1092 static const struct file_operations nfs_volume_list_fops = {
1093 	.open		= nfs_volume_list_open,
1094 	.read		= seq_read,
1095 	.llseek		= seq_lseek,
1096 	.release	= seq_release_net,
1097 };
1098 
1099 /*
1100  * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
1101  * we're dealing
1102  */
1103 static int nfs_server_list_open(struct inode *inode, struct file *file)
1104 {
1105 	return seq_open_net(inode, file, &nfs_server_list_ops,
1106 			   sizeof(struct seq_net_private));
1107 }
1108 
1109 /*
1110  * set up the iterator to start reading from the server list and return the first item
1111  */
1112 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1113 				__acquires(&nn->nfs_client_lock)
1114 {
1115 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1116 
1117 	/* lock the list against modification */
1118 	spin_lock(&nn->nfs_client_lock);
1119 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1120 }
1121 
1122 /*
1123  * move to next server
1124  */
1125 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1126 {
1127 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1128 
1129 	return seq_list_next(v, &nn->nfs_client_list, pos);
1130 }
1131 
1132 /*
1133  * clean up after reading from the transports list
1134  */
1135 static void nfs_server_list_stop(struct seq_file *p, void *v)
1136 				__releases(&nn->nfs_client_lock)
1137 {
1138 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1139 
1140 	spin_unlock(&nn->nfs_client_lock);
1141 }
1142 
1143 /*
1144  * display a header line followed by a load of call lines
1145  */
1146 static int nfs_server_list_show(struct seq_file *m, void *v)
1147 {
1148 	struct nfs_client *clp;
1149 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1150 
1151 	/* display header on line 1 */
1152 	if (v == &nn->nfs_client_list) {
1153 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1154 		return 0;
1155 	}
1156 
1157 	/* display one transport per line on subsequent lines */
1158 	clp = list_entry(v, struct nfs_client, cl_share_link);
1159 
1160 	/* Check if the client is initialized */
1161 	if (clp->cl_cons_state != NFS_CS_READY)
1162 		return 0;
1163 
1164 	rcu_read_lock();
1165 	seq_printf(m, "v%u %s %s %3d %s\n",
1166 		   clp->rpc_ops->version,
1167 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1168 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1169 		   refcount_read(&clp->cl_count),
1170 		   clp->cl_hostname);
1171 	rcu_read_unlock();
1172 
1173 	return 0;
1174 }
1175 
1176 /*
1177  * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
1178  */
1179 static int nfs_volume_list_open(struct inode *inode, struct file *file)
1180 {
1181 	return seq_open_net(inode, file, &nfs_volume_list_ops,
1182 			   sizeof(struct seq_net_private));
1183 }
1184 
1185 /*
1186  * set up the iterator to start reading from the volume list and return the first item
1187  */
1188 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1189 				__acquires(&nn->nfs_client_lock)
1190 {
1191 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1192 
1193 	/* lock the list against modification */
1194 	spin_lock(&nn->nfs_client_lock);
1195 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1196 }
1197 
1198 /*
1199  * move to next volume
1200  */
1201 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1202 {
1203 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1204 
1205 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1206 }
1207 
1208 /*
1209  * clean up after reading from the transports list
1210  */
1211 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1212 				__releases(&nn->nfs_client_lock)
1213 {
1214 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1215 
1216 	spin_unlock(&nn->nfs_client_lock);
1217 }
1218 
1219 /*
1220  * display a header line followed by a load of call lines
1221  */
1222 static int nfs_volume_list_show(struct seq_file *m, void *v)
1223 {
1224 	struct nfs_server *server;
1225 	struct nfs_client *clp;
1226 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1227 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1228 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1229 
1230 	/* display header on line 1 */
1231 	if (v == &nn->nfs_volume_list) {
1232 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1233 			    "                              FSC\n");
1234 		return 0;
1235 	}
1236 	/* display one transport per line on subsequent lines */
1237 	server = list_entry(v, struct nfs_server, master_link);
1238 	clp = server->nfs_client;
1239 
1240 	snprintf(dev, sizeof(dev), "%u:%u",
1241 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1242 
1243 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1244 		 (unsigned long long) server->fsid.major,
1245 		 (unsigned long long) server->fsid.minor);
1246 
1247 	rcu_read_lock();
1248 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1249 		   clp->rpc_ops->version,
1250 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1251 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1252 		   dev,
1253 		   fsid,
1254 		   nfs_server_fscache_state(server));
1255 	rcu_read_unlock();
1256 
1257 	return 0;
1258 }
1259 
1260 int nfs_fs_proc_net_init(struct net *net)
1261 {
1262 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1263 	struct proc_dir_entry *p;
1264 
1265 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1266 	if (!nn->proc_nfsfs)
1267 		goto error_0;
1268 
1269 	/* a file of servers with which we're dealing */
1270 	p = proc_create("servers", S_IFREG|S_IRUGO,
1271 			nn->proc_nfsfs, &nfs_server_list_fops);
1272 	if (!p)
1273 		goto error_1;
1274 
1275 	/* a file of volumes that we have mounted */
1276 	p = proc_create("volumes", S_IFREG|S_IRUGO,
1277 			nn->proc_nfsfs, &nfs_volume_list_fops);
1278 	if (!p)
1279 		goto error_1;
1280 	return 0;
1281 
1282 error_1:
1283 	remove_proc_subtree("nfsfs", net->proc_net);
1284 error_0:
1285 	return -ENOMEM;
1286 }
1287 
1288 void nfs_fs_proc_net_exit(struct net *net)
1289 {
1290 	remove_proc_subtree("nfsfs", net->proc_net);
1291 }
1292 
1293 /*
1294  * initialise the /proc/fs/nfsfs/ directory
1295  */
1296 int __init nfs_fs_proc_init(void)
1297 {
1298 	if (!proc_mkdir("fs/nfsfs", NULL))
1299 		goto error_0;
1300 
1301 	/* a file of servers with which we're dealing */
1302 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1303 		goto error_1;
1304 
1305 	/* a file of volumes that we have mounted */
1306 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1307 		goto error_1;
1308 
1309 	return 0;
1310 error_1:
1311 	remove_proc_subtree("fs/nfsfs", NULL);
1312 error_0:
1313 	return -ENOMEM;
1314 }
1315 
1316 /*
1317  * clean up the /proc/fs/nfsfs/ directory
1318  */
1319 void nfs_fs_proc_exit(void)
1320 {
1321 	remove_proc_subtree("fs/nfsfs", NULL);
1322 }
1323 
1324 #endif /* CONFIG_PROC_FS */
1325