xref: /openbmc/linux/fs/nfs/client.c (revision be78b59e)
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 	atomic_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 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
222 }
223 
224 #else
225 void nfs_cleanup_cb_ident_idr(struct net *net)
226 {
227 }
228 
229 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
230 {
231 }
232 
233 static void pnfs_init_server(struct nfs_server *server)
234 {
235 }
236 
237 #endif /* CONFIG_NFS_V4 */
238 
239 /*
240  * Destroy a shared client record
241  */
242 void nfs_free_client(struct nfs_client *clp)
243 {
244 	nfs_fscache_release_client_cookie(clp);
245 
246 	/* -EIO all pending I/O */
247 	if (!IS_ERR(clp->cl_rpcclient))
248 		rpc_shutdown_client(clp->cl_rpcclient);
249 
250 	if (clp->cl_machine_cred != NULL)
251 		put_rpccred(clp->cl_machine_cred);
252 
253 	put_net(clp->cl_net);
254 	put_nfs_version(clp->cl_nfs_mod);
255 	kfree(clp->cl_hostname);
256 	kfree(clp->cl_acceptor);
257 	kfree(clp);
258 }
259 EXPORT_SYMBOL_GPL(nfs_free_client);
260 
261 /*
262  * Release a reference to a shared client record
263  */
264 void nfs_put_client(struct nfs_client *clp)
265 {
266 	struct nfs_net *nn;
267 
268 	if (!clp)
269 		return;
270 
271 	nn = net_generic(clp->cl_net, nfs_net_id);
272 
273 	if (atomic_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
274 		list_del(&clp->cl_share_link);
275 		nfs_cb_idr_remove_locked(clp);
276 		spin_unlock(&nn->nfs_client_lock);
277 
278 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
279 
280 		clp->rpc_ops->free_client(clp);
281 	}
282 }
283 EXPORT_SYMBOL_GPL(nfs_put_client);
284 
285 /*
286  * Find an nfs_client on the list that matches the initialisation data
287  * that is supplied.
288  */
289 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
290 {
291 	struct nfs_client *clp;
292 	const struct sockaddr *sap = data->addr;
293 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
294 
295 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
296 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
297 		/* Don't match clients that failed to initialise properly */
298 		if (clp->cl_cons_state < 0)
299 			continue;
300 
301 		/* Different NFS versions cannot share the same nfs_client */
302 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
303 			continue;
304 
305 		if (clp->cl_proto != data->proto)
306 			continue;
307 		/* Match nfsv4 minorversion */
308 		if (clp->cl_minorversion != data->minorversion)
309 			continue;
310 		/* Match the full socket address */
311 		if (!rpc_cmp_addr_port(sap, clap))
312 			/* Match all xprt_switch full socket addresses */
313 			if (IS_ERR(clp->cl_rpcclient) ||
314                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
315 							   sap))
316 				continue;
317 
318 		atomic_inc(&clp->cl_count);
319 		return clp;
320 	}
321 	return NULL;
322 }
323 
324 /*
325  * Return true if @clp is done initializing, false if still working on it.
326  *
327  * Use nfs_client_init_status to check if it was successful.
328  */
329 bool nfs_client_init_is_complete(const struct nfs_client *clp)
330 {
331 	return clp->cl_cons_state <= NFS_CS_READY;
332 }
333 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
334 
335 /*
336  * Return 0 if @clp was successfully initialized, -errno otherwise.
337  *
338  * This must be called *after* nfs_client_init_is_complete() returns true,
339  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
340  */
341 int nfs_client_init_status(const struct nfs_client *clp)
342 {
343 	/* called without checking nfs_client_init_is_complete */
344 	if (clp->cl_cons_state > NFS_CS_READY) {
345 		WARN_ON_ONCE(1);
346 		return -EINVAL;
347 	}
348 	return clp->cl_cons_state;
349 }
350 EXPORT_SYMBOL_GPL(nfs_client_init_status);
351 
352 int nfs_wait_client_init_complete(const struct nfs_client *clp)
353 {
354 	return wait_event_killable(nfs_client_active_wq,
355 			nfs_client_init_is_complete(clp));
356 }
357 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
358 
359 /*
360  * Found an existing client.  Make sure it's ready before returning.
361  */
362 static struct nfs_client *
363 nfs_found_client(const struct nfs_client_initdata *cl_init,
364 		 struct nfs_client *clp)
365 {
366 	int error;
367 
368 	error = nfs_wait_client_init_complete(clp);
369 	if (error < 0) {
370 		nfs_put_client(clp);
371 		return ERR_PTR(-ERESTARTSYS);
372 	}
373 
374 	if (clp->cl_cons_state < NFS_CS_READY) {
375 		error = clp->cl_cons_state;
376 		nfs_put_client(clp);
377 		return ERR_PTR(error);
378 	}
379 
380 	smp_rmb();
381 	return clp;
382 }
383 
384 /*
385  * Look up a client by IP address and protocol version
386  * - creates a new record if one doesn't yet exist
387  */
388 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
389 {
390 	struct nfs_client *clp, *new = NULL;
391 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
392 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
393 
394 	if (cl_init->hostname == NULL) {
395 		WARN_ON(1);
396 		return NULL;
397 	}
398 
399 	/* see if the client already exists */
400 	do {
401 		spin_lock(&nn->nfs_client_lock);
402 
403 		clp = nfs_match_client(cl_init);
404 		if (clp) {
405 			spin_unlock(&nn->nfs_client_lock);
406 			if (new)
407 				new->rpc_ops->free_client(new);
408 			return nfs_found_client(cl_init, clp);
409 		}
410 		if (new) {
411 			list_add_tail(&new->cl_share_link,
412 					&nn->nfs_client_list);
413 			spin_unlock(&nn->nfs_client_lock);
414 			new->cl_flags = cl_init->init_flags;
415 			return rpc_ops->init_client(new, cl_init);
416 		}
417 
418 		spin_unlock(&nn->nfs_client_lock);
419 
420 		new = rpc_ops->alloc_client(cl_init);
421 	} while (!IS_ERR(new));
422 
423 	return new;
424 }
425 EXPORT_SYMBOL_GPL(nfs_get_client);
426 
427 /*
428  * Mark a server as ready or failed
429  */
430 void nfs_mark_client_ready(struct nfs_client *clp, int state)
431 {
432 	smp_wmb();
433 	clp->cl_cons_state = state;
434 	wake_up_all(&nfs_client_active_wq);
435 }
436 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
437 
438 /*
439  * Initialise the timeout values for a connection
440  */
441 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
442 				    int timeo, int retrans)
443 {
444 	to->to_initval = timeo * HZ / 10;
445 	to->to_retries = retrans;
446 
447 	switch (proto) {
448 	case XPRT_TRANSPORT_TCP:
449 	case XPRT_TRANSPORT_RDMA:
450 		if (retrans == NFS_UNSPEC_RETRANS)
451 			to->to_retries = NFS_DEF_TCP_RETRANS;
452 		if (timeo == NFS_UNSPEC_TIMEO || to->to_retries == 0)
453 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
454 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
455 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
456 		to->to_increment = to->to_initval;
457 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
458 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
459 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
460 		if (to->to_maxval < to->to_initval)
461 			to->to_maxval = to->to_initval;
462 		to->to_exponential = 0;
463 		break;
464 	case XPRT_TRANSPORT_UDP:
465 		if (retrans == NFS_UNSPEC_RETRANS)
466 			to->to_retries = NFS_DEF_UDP_RETRANS;
467 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
468 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
469 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
470 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
471 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
472 		to->to_exponential = 1;
473 		break;
474 	default:
475 		BUG();
476 	}
477 }
478 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
479 
480 /*
481  * Create an RPC client handle
482  */
483 int nfs_create_rpc_client(struct nfs_client *clp,
484 			  const struct nfs_client_initdata *cl_init,
485 			  rpc_authflavor_t flavor)
486 {
487 	struct rpc_clnt		*clnt = NULL;
488 	struct rpc_create_args args = {
489 		.net		= clp->cl_net,
490 		.protocol	= clp->cl_proto,
491 		.address	= (struct sockaddr *)&clp->cl_addr,
492 		.addrsize	= clp->cl_addrlen,
493 		.timeout	= cl_init->timeparms,
494 		.servername	= clp->cl_hostname,
495 		.nodename	= cl_init->nodename,
496 		.program	= &nfs_program,
497 		.version	= clp->rpc_ops->version,
498 		.authflavor	= flavor,
499 	};
500 
501 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
502 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
503 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
504 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
505 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
506 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
507 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
508 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
509 
510 	if (!IS_ERR(clp->cl_rpcclient))
511 		return 0;
512 
513 	clnt = rpc_create(&args);
514 	if (IS_ERR(clnt)) {
515 		dprintk("%s: cannot create RPC client. Error = %ld\n",
516 				__func__, PTR_ERR(clnt));
517 		return PTR_ERR(clnt);
518 	}
519 
520 	clp->cl_rpcclient = clnt;
521 	return 0;
522 }
523 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
524 
525 /*
526  * Version 2 or 3 client destruction
527  */
528 static void nfs_destroy_server(struct nfs_server *server)
529 {
530 	if (server->nlm_host)
531 		nlmclnt_done(server->nlm_host);
532 }
533 
534 /*
535  * Version 2 or 3 lockd setup
536  */
537 static int nfs_start_lockd(struct nfs_server *server)
538 {
539 	struct nlm_host *host;
540 	struct nfs_client *clp = server->nfs_client;
541 	struct nlmclnt_initdata nlm_init = {
542 		.hostname	= clp->cl_hostname,
543 		.address	= (struct sockaddr *)&clp->cl_addr,
544 		.addrlen	= clp->cl_addrlen,
545 		.nfs_version	= clp->rpc_ops->version,
546 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
547 					1 : 0,
548 		.net		= clp->cl_net,
549 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
550 	};
551 
552 	if (nlm_init.nfs_version > 3)
553 		return 0;
554 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
555 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
556 		return 0;
557 
558 	switch (clp->cl_proto) {
559 		default:
560 			nlm_init.protocol = IPPROTO_TCP;
561 			break;
562 		case XPRT_TRANSPORT_UDP:
563 			nlm_init.protocol = IPPROTO_UDP;
564 	}
565 
566 	host = nlmclnt_init(&nlm_init);
567 	if (IS_ERR(host))
568 		return PTR_ERR(host);
569 
570 	server->nlm_host = host;
571 	server->destroy = nfs_destroy_server;
572 	return 0;
573 }
574 
575 /*
576  * Create a general RPC client
577  */
578 int nfs_init_server_rpcclient(struct nfs_server *server,
579 		const struct rpc_timeout *timeo,
580 		rpc_authflavor_t pseudoflavour)
581 {
582 	struct nfs_client *clp = server->nfs_client;
583 
584 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
585 							pseudoflavour);
586 	if (IS_ERR(server->client)) {
587 		dprintk("%s: couldn't create rpc_client!\n", __func__);
588 		return PTR_ERR(server->client);
589 	}
590 
591 	memcpy(&server->client->cl_timeout_default,
592 			timeo,
593 			sizeof(server->client->cl_timeout_default));
594 	server->client->cl_timeout = &server->client->cl_timeout_default;
595 	server->client->cl_softrtry = 0;
596 	if (server->flags & NFS_MOUNT_SOFT)
597 		server->client->cl_softrtry = 1;
598 
599 	return 0;
600 }
601 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
602 
603 /**
604  * nfs_init_client - Initialise an NFS2 or NFS3 client
605  *
606  * @clp: nfs_client to initialise
607  * @cl_init: Initialisation parameters
608  *
609  * Returns pointer to an NFS client, or an ERR_PTR value.
610  */
611 struct nfs_client *nfs_init_client(struct nfs_client *clp,
612 				   const struct nfs_client_initdata *cl_init)
613 {
614 	int error;
615 
616 	/* the client is already initialised */
617 	if (clp->cl_cons_state == NFS_CS_READY)
618 		return clp;
619 
620 	/*
621 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
622 	 * - RFC 2623, sec 2.3.2
623 	 */
624 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
625 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
626 	if (error < 0) {
627 		nfs_put_client(clp);
628 		clp = ERR_PTR(error);
629 	}
630 	return clp;
631 }
632 EXPORT_SYMBOL_GPL(nfs_init_client);
633 
634 /*
635  * Create a version 2 or 3 client
636  */
637 static int nfs_init_server(struct nfs_server *server,
638 			   const struct nfs_parsed_mount_data *data,
639 			   struct nfs_subversion *nfs_mod)
640 {
641 	struct rpc_timeout timeparms;
642 	struct nfs_client_initdata cl_init = {
643 		.hostname = data->nfs_server.hostname,
644 		.addr = (const struct sockaddr *)&data->nfs_server.address,
645 		.addrlen = data->nfs_server.addrlen,
646 		.nfs_mod = nfs_mod,
647 		.proto = data->nfs_server.protocol,
648 		.net = data->net,
649 		.timeparms = &timeparms,
650 	};
651 	struct nfs_client *clp;
652 	int error;
653 
654 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
655 			data->timeo, data->retrans);
656 	if (data->flags & NFS_MOUNT_NORESVPORT)
657 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
658 
659 	/* Allocate or find a client reference we can use */
660 	clp = nfs_get_client(&cl_init);
661 	if (IS_ERR(clp))
662 		return PTR_ERR(clp);
663 
664 	server->nfs_client = clp;
665 
666 	/* Initialise the client representation from the mount data */
667 	server->flags = data->flags;
668 	server->options = data->options;
669 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
670 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
671 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
672 
673 	if (data->rsize)
674 		server->rsize = nfs_block_size(data->rsize, NULL);
675 	if (data->wsize)
676 		server->wsize = nfs_block_size(data->wsize, NULL);
677 
678 	server->acregmin = data->acregmin * HZ;
679 	server->acregmax = data->acregmax * HZ;
680 	server->acdirmin = data->acdirmin * HZ;
681 	server->acdirmax = data->acdirmax * HZ;
682 
683 	/* Start lockd here, before we might error out */
684 	error = nfs_start_lockd(server);
685 	if (error < 0)
686 		goto error;
687 
688 	server->port = data->nfs_server.port;
689 	server->auth_info = data->auth_info;
690 
691 	error = nfs_init_server_rpcclient(server, &timeparms,
692 					  data->selected_flavor);
693 	if (error < 0)
694 		goto error;
695 
696 	/* Preserve the values of mount_server-related mount options */
697 	if (data->mount_server.addrlen) {
698 		memcpy(&server->mountd_address, &data->mount_server.address,
699 			data->mount_server.addrlen);
700 		server->mountd_addrlen = data->mount_server.addrlen;
701 	}
702 	server->mountd_version = data->mount_server.version;
703 	server->mountd_port = data->mount_server.port;
704 	server->mountd_protocol = data->mount_server.protocol;
705 
706 	server->namelen  = data->namlen;
707 	return 0;
708 
709 error:
710 	server->nfs_client = NULL;
711 	nfs_put_client(clp);
712 	return error;
713 }
714 
715 /*
716  * Load up the server record from information gained in an fsinfo record
717  */
718 static void nfs_server_set_fsinfo(struct nfs_server *server,
719 				  struct nfs_fsinfo *fsinfo)
720 {
721 	unsigned long max_rpc_payload;
722 
723 	/* Work out a lot of parameters */
724 	if (server->rsize == 0)
725 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
726 	if (server->wsize == 0)
727 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
728 
729 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
730 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
731 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
732 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
733 
734 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
735 	if (server->rsize > max_rpc_payload)
736 		server->rsize = max_rpc_payload;
737 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
738 		server->rsize = NFS_MAX_FILE_IO_SIZE;
739 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
740 
741 	if (server->wsize > max_rpc_payload)
742 		server->wsize = max_rpc_payload;
743 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
744 		server->wsize = NFS_MAX_FILE_IO_SIZE;
745 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
746 
747 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
748 
749 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
750 	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
751 		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
752 	if (server->dtsize > server->rsize)
753 		server->dtsize = server->rsize;
754 
755 	if (server->flags & NFS_MOUNT_NOAC) {
756 		server->acregmin = server->acregmax = 0;
757 		server->acdirmin = server->acdirmax = 0;
758 	}
759 
760 	server->maxfilesize = fsinfo->maxfilesize;
761 
762 	server->time_delta = fsinfo->time_delta;
763 
764 	server->clone_blksize = fsinfo->clone_blksize;
765 	/* We're airborne Set socket buffersize */
766 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
767 }
768 
769 /*
770  * Probe filesystem information, including the FSID on v2/v3
771  */
772 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
773 {
774 	struct nfs_fsinfo fsinfo;
775 	struct nfs_client *clp = server->nfs_client;
776 	int error;
777 
778 	if (clp->rpc_ops->set_capabilities != NULL) {
779 		error = clp->rpc_ops->set_capabilities(server, mntfh);
780 		if (error < 0)
781 			return error;
782 	}
783 
784 	fsinfo.fattr = fattr;
785 	fsinfo.nlayouttypes = 0;
786 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
787 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
788 	if (error < 0)
789 		return error;
790 
791 	nfs_server_set_fsinfo(server, &fsinfo);
792 
793 	/* Get some general file system info */
794 	if (server->namelen == 0) {
795 		struct nfs_pathconf pathinfo;
796 
797 		pathinfo.fattr = fattr;
798 		nfs_fattr_init(fattr);
799 
800 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
801 			server->namelen = pathinfo.max_namelen;
802 	}
803 
804 	return 0;
805 }
806 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
807 
808 /*
809  * Copy useful information when duplicating a server record
810  */
811 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
812 {
813 	target->flags = source->flags;
814 	target->rsize = source->rsize;
815 	target->wsize = source->wsize;
816 	target->acregmin = source->acregmin;
817 	target->acregmax = source->acregmax;
818 	target->acdirmin = source->acdirmin;
819 	target->acdirmax = source->acdirmax;
820 	target->caps = source->caps;
821 	target->options = source->options;
822 	target->auth_info = source->auth_info;
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 
891 	return server;
892 }
893 EXPORT_SYMBOL_GPL(nfs_alloc_server);
894 
895 /*
896  * Free up a server record
897  */
898 void nfs_free_server(struct nfs_server *server)
899 {
900 	nfs_server_remove_lists(server);
901 
902 	if (server->destroy != NULL)
903 		server->destroy(server);
904 
905 	if (!IS_ERR(server->client_acl))
906 		rpc_shutdown_client(server->client_acl);
907 	if (!IS_ERR(server->client))
908 		rpc_shutdown_client(server->client);
909 
910 	nfs_put_client(server->nfs_client);
911 
912 	ida_destroy(&server->lockowner_id);
913 	ida_destroy(&server->openowner_id);
914 	nfs_free_iostats(server->io_stats);
915 	kfree(server);
916 	nfs_release_automount_timer();
917 }
918 EXPORT_SYMBOL_GPL(nfs_free_server);
919 
920 /*
921  * Create a version 2 or 3 volume record
922  * - keyed on server and FSID
923  */
924 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
925 				     struct nfs_subversion *nfs_mod)
926 {
927 	struct nfs_server *server;
928 	struct nfs_fattr *fattr;
929 	int error;
930 
931 	server = nfs_alloc_server();
932 	if (!server)
933 		return ERR_PTR(-ENOMEM);
934 
935 	error = -ENOMEM;
936 	fattr = nfs_alloc_fattr();
937 	if (fattr == NULL)
938 		goto error;
939 
940 	/* Get a client representation */
941 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
942 	if (error < 0)
943 		goto error;
944 
945 	/* Probe the root fh to retrieve its FSID */
946 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
947 	if (error < 0)
948 		goto error;
949 	if (server->nfs_client->rpc_ops->version == 3) {
950 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
951 			server->namelen = NFS3_MAXNAMLEN;
952 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
953 			server->caps |= NFS_CAP_READDIRPLUS;
954 	} else {
955 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
956 			server->namelen = NFS2_MAXNAMLEN;
957 	}
958 
959 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
960 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh, fattr, NULL);
961 		if (error < 0) {
962 			dprintk("nfs_create_server: getattr error = %d\n", -error);
963 			goto error;
964 		}
965 	}
966 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
967 
968 	dprintk("Server FSID: %llx:%llx\n",
969 		(unsigned long long) server->fsid.major,
970 		(unsigned long long) server->fsid.minor);
971 
972 	nfs_server_insert_lists(server);
973 	server->mount_time = jiffies;
974 	nfs_free_fattr(fattr);
975 	return server;
976 
977 error:
978 	nfs_free_fattr(fattr);
979 	nfs_free_server(server);
980 	return ERR_PTR(error);
981 }
982 EXPORT_SYMBOL_GPL(nfs_create_server);
983 
984 /*
985  * Clone an NFS2, NFS3 or NFS4 server record
986  */
987 struct nfs_server *nfs_clone_server(struct nfs_server *source,
988 				    struct nfs_fh *fh,
989 				    struct nfs_fattr *fattr,
990 				    rpc_authflavor_t flavor)
991 {
992 	struct nfs_server *server;
993 	struct nfs_fattr *fattr_fsinfo;
994 	int error;
995 
996 	server = nfs_alloc_server();
997 	if (!server)
998 		return ERR_PTR(-ENOMEM);
999 
1000 	error = -ENOMEM;
1001 	fattr_fsinfo = nfs_alloc_fattr();
1002 	if (fattr_fsinfo == NULL)
1003 		goto out_free_server;
1004 
1005 	/* Copy data from the source */
1006 	server->nfs_client = source->nfs_client;
1007 	server->destroy = source->destroy;
1008 	atomic_inc(&server->nfs_client->cl_count);
1009 	nfs_server_copy_userdata(server, source);
1010 
1011 	server->fsid = fattr->fsid;
1012 
1013 	error = nfs_init_server_rpcclient(server,
1014 			source->client->cl_timeout,
1015 			flavor);
1016 	if (error < 0)
1017 		goto out_free_server;
1018 
1019 	/* probe the filesystem info for this server filesystem */
1020 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1021 	if (error < 0)
1022 		goto out_free_server;
1023 
1024 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1025 		server->namelen = NFS4_MAXNAMLEN;
1026 
1027 	error = nfs_start_lockd(server);
1028 	if (error < 0)
1029 		goto out_free_server;
1030 
1031 	nfs_server_insert_lists(server);
1032 	server->mount_time = jiffies;
1033 
1034 	nfs_free_fattr(fattr_fsinfo);
1035 	return server;
1036 
1037 out_free_server:
1038 	nfs_free_fattr(fattr_fsinfo);
1039 	nfs_free_server(server);
1040 	return ERR_PTR(error);
1041 }
1042 EXPORT_SYMBOL_GPL(nfs_clone_server);
1043 
1044 void nfs_clients_init(struct net *net)
1045 {
1046 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1047 
1048 	INIT_LIST_HEAD(&nn->nfs_client_list);
1049 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1050 #if IS_ENABLED(CONFIG_NFS_V4)
1051 	idr_init(&nn->cb_ident_idr);
1052 #endif
1053 	spin_lock_init(&nn->nfs_client_lock);
1054 	nn->boot_time = ktime_get_real();
1055 }
1056 
1057 #ifdef CONFIG_PROC_FS
1058 static int nfs_server_list_open(struct inode *inode, struct file *file);
1059 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1060 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1061 static void nfs_server_list_stop(struct seq_file *p, void *v);
1062 static int nfs_server_list_show(struct seq_file *m, void *v);
1063 
1064 static const struct seq_operations nfs_server_list_ops = {
1065 	.start	= nfs_server_list_start,
1066 	.next	= nfs_server_list_next,
1067 	.stop	= nfs_server_list_stop,
1068 	.show	= nfs_server_list_show,
1069 };
1070 
1071 static const struct file_operations nfs_server_list_fops = {
1072 	.open		= nfs_server_list_open,
1073 	.read		= seq_read,
1074 	.llseek		= seq_lseek,
1075 	.release	= seq_release_net,
1076 };
1077 
1078 static int nfs_volume_list_open(struct inode *inode, struct file *file);
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 static const struct file_operations nfs_volume_list_fops = {
1092 	.open		= nfs_volume_list_open,
1093 	.read		= seq_read,
1094 	.llseek		= seq_lseek,
1095 	.release	= seq_release_net,
1096 };
1097 
1098 /*
1099  * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
1100  * we're dealing
1101  */
1102 static int nfs_server_list_open(struct inode *inode, struct file *file)
1103 {
1104 	return seq_open_net(inode, file, &nfs_server_list_ops,
1105 			   sizeof(struct seq_net_private));
1106 }
1107 
1108 /*
1109  * set up the iterator to start reading from the server list and return the first item
1110  */
1111 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1112 				__acquires(&nn->nfs_client_lock)
1113 {
1114 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1115 
1116 	/* lock the list against modification */
1117 	spin_lock(&nn->nfs_client_lock);
1118 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1119 }
1120 
1121 /*
1122  * move to next server
1123  */
1124 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1125 {
1126 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1127 
1128 	return seq_list_next(v, &nn->nfs_client_list, pos);
1129 }
1130 
1131 /*
1132  * clean up after reading from the transports list
1133  */
1134 static void nfs_server_list_stop(struct seq_file *p, void *v)
1135 				__releases(&nn->nfs_client_lock)
1136 {
1137 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1138 
1139 	spin_unlock(&nn->nfs_client_lock);
1140 }
1141 
1142 /*
1143  * display a header line followed by a load of call lines
1144  */
1145 static int nfs_server_list_show(struct seq_file *m, void *v)
1146 {
1147 	struct nfs_client *clp;
1148 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1149 
1150 	/* display header on line 1 */
1151 	if (v == &nn->nfs_client_list) {
1152 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1153 		return 0;
1154 	}
1155 
1156 	/* display one transport per line on subsequent lines */
1157 	clp = list_entry(v, struct nfs_client, cl_share_link);
1158 
1159 	/* Check if the client is initialized */
1160 	if (clp->cl_cons_state != NFS_CS_READY)
1161 		return 0;
1162 
1163 	rcu_read_lock();
1164 	seq_printf(m, "v%u %s %s %3d %s\n",
1165 		   clp->rpc_ops->version,
1166 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1167 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1168 		   atomic_read(&clp->cl_count),
1169 		   clp->cl_hostname);
1170 	rcu_read_unlock();
1171 
1172 	return 0;
1173 }
1174 
1175 /*
1176  * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
1177  */
1178 static int nfs_volume_list_open(struct inode *inode, struct file *file)
1179 {
1180 	return seq_open_net(inode, file, &nfs_volume_list_ops,
1181 			   sizeof(struct seq_net_private));
1182 }
1183 
1184 /*
1185  * set up the iterator to start reading from the volume list and return the first item
1186  */
1187 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1188 				__acquires(&nn->nfs_client_lock)
1189 {
1190 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1191 
1192 	/* lock the list against modification */
1193 	spin_lock(&nn->nfs_client_lock);
1194 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1195 }
1196 
1197 /*
1198  * move to next volume
1199  */
1200 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1201 {
1202 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1203 
1204 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1205 }
1206 
1207 /*
1208  * clean up after reading from the transports list
1209  */
1210 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1211 				__releases(&nn->nfs_client_lock)
1212 {
1213 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1214 
1215 	spin_unlock(&nn->nfs_client_lock);
1216 }
1217 
1218 /*
1219  * display a header line followed by a load of call lines
1220  */
1221 static int nfs_volume_list_show(struct seq_file *m, void *v)
1222 {
1223 	struct nfs_server *server;
1224 	struct nfs_client *clp;
1225 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1226 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1227 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1228 
1229 	/* display header on line 1 */
1230 	if (v == &nn->nfs_volume_list) {
1231 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1232 			    "                              FSC\n");
1233 		return 0;
1234 	}
1235 	/* display one transport per line on subsequent lines */
1236 	server = list_entry(v, struct nfs_server, master_link);
1237 	clp = server->nfs_client;
1238 
1239 	snprintf(dev, sizeof(dev), "%u:%u",
1240 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1241 
1242 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1243 		 (unsigned long long) server->fsid.major,
1244 		 (unsigned long long) server->fsid.minor);
1245 
1246 	rcu_read_lock();
1247 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1248 		   clp->rpc_ops->version,
1249 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1250 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1251 		   dev,
1252 		   fsid,
1253 		   nfs_server_fscache_state(server));
1254 	rcu_read_unlock();
1255 
1256 	return 0;
1257 }
1258 
1259 int nfs_fs_proc_net_init(struct net *net)
1260 {
1261 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1262 	struct proc_dir_entry *p;
1263 
1264 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1265 	if (!nn->proc_nfsfs)
1266 		goto error_0;
1267 
1268 	/* a file of servers with which we're dealing */
1269 	p = proc_create("servers", S_IFREG|S_IRUGO,
1270 			nn->proc_nfsfs, &nfs_server_list_fops);
1271 	if (!p)
1272 		goto error_1;
1273 
1274 	/* a file of volumes that we have mounted */
1275 	p = proc_create("volumes", S_IFREG|S_IRUGO,
1276 			nn->proc_nfsfs, &nfs_volume_list_fops);
1277 	if (!p)
1278 		goto error_1;
1279 	return 0;
1280 
1281 error_1:
1282 	remove_proc_subtree("nfsfs", net->proc_net);
1283 error_0:
1284 	return -ENOMEM;
1285 }
1286 
1287 void nfs_fs_proc_net_exit(struct net *net)
1288 {
1289 	remove_proc_subtree("nfsfs", net->proc_net);
1290 }
1291 
1292 /*
1293  * initialise the /proc/fs/nfsfs/ directory
1294  */
1295 int __init nfs_fs_proc_init(void)
1296 {
1297 	if (!proc_mkdir("fs/nfsfs", NULL))
1298 		goto error_0;
1299 
1300 	/* a file of servers with which we're dealing */
1301 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1302 		goto error_1;
1303 
1304 	/* a file of volumes that we have mounted */
1305 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1306 		goto error_1;
1307 
1308 	return 0;
1309 error_1:
1310 	remove_proc_subtree("fs/nfsfs", NULL);
1311 error_0:
1312 	return -ENOMEM;
1313 }
1314 
1315 /*
1316  * clean up the /proc/fs/nfsfs/ directory
1317  */
1318 void nfs_fs_proc_exit(void)
1319 {
1320 	remove_proc_subtree("fs/nfsfs", NULL);
1321 }
1322 
1323 #endif /* CONFIG_PROC_FS */
1324