xref: /openbmc/linux/fs/nfs/client.c (revision 2c64e9cb)
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 	int error;
288 
289 again:
290 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
291 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
292 		/* Don't match clients that failed to initialise properly */
293 		if (clp->cl_cons_state < 0)
294 			continue;
295 
296 		/* If a client is still initializing then we need to wait */
297 		if (clp->cl_cons_state > NFS_CS_READY) {
298 			refcount_inc(&clp->cl_count);
299 			spin_unlock(&nn->nfs_client_lock);
300 			error = nfs_wait_client_init_complete(clp);
301 			nfs_put_client(clp);
302 			spin_lock(&nn->nfs_client_lock);
303 			if (error < 0)
304 				return ERR_PTR(error);
305 			goto again;
306 		}
307 
308 		/* Different NFS versions cannot share the same nfs_client */
309 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
310 			continue;
311 
312 		if (clp->cl_proto != data->proto)
313 			continue;
314 		/* Match nfsv4 minorversion */
315 		if (clp->cl_minorversion != data->minorversion)
316 			continue;
317 		/* Match the full socket address */
318 		if (!rpc_cmp_addr_port(sap, clap))
319 			/* Match all xprt_switch full socket addresses */
320 			if (IS_ERR(clp->cl_rpcclient) ||
321                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
322 							   sap))
323 				continue;
324 
325 		refcount_inc(&clp->cl_count);
326 		return clp;
327 	}
328 	return NULL;
329 }
330 
331 /*
332  * Return true if @clp is done initializing, false if still working on it.
333  *
334  * Use nfs_client_init_status to check if it was successful.
335  */
336 bool nfs_client_init_is_complete(const struct nfs_client *clp)
337 {
338 	return clp->cl_cons_state <= NFS_CS_READY;
339 }
340 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
341 
342 /*
343  * Return 0 if @clp was successfully initialized, -errno otherwise.
344  *
345  * This must be called *after* nfs_client_init_is_complete() returns true,
346  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
347  */
348 int nfs_client_init_status(const struct nfs_client *clp)
349 {
350 	/* called without checking nfs_client_init_is_complete */
351 	if (clp->cl_cons_state > NFS_CS_READY) {
352 		WARN_ON_ONCE(1);
353 		return -EINVAL;
354 	}
355 	return clp->cl_cons_state;
356 }
357 EXPORT_SYMBOL_GPL(nfs_client_init_status);
358 
359 int nfs_wait_client_init_complete(const struct nfs_client *clp)
360 {
361 	return wait_event_killable(nfs_client_active_wq,
362 			nfs_client_init_is_complete(clp));
363 }
364 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
365 
366 /*
367  * Found an existing client.  Make sure it's ready before returning.
368  */
369 static struct nfs_client *
370 nfs_found_client(const struct nfs_client_initdata *cl_init,
371 		 struct nfs_client *clp)
372 {
373 	int error;
374 
375 	error = nfs_wait_client_init_complete(clp);
376 	if (error < 0) {
377 		nfs_put_client(clp);
378 		return ERR_PTR(-ERESTARTSYS);
379 	}
380 
381 	if (clp->cl_cons_state < NFS_CS_READY) {
382 		error = clp->cl_cons_state;
383 		nfs_put_client(clp);
384 		return ERR_PTR(error);
385 	}
386 
387 	smp_rmb();
388 	return clp;
389 }
390 
391 /*
392  * Look up a client by IP address and protocol version
393  * - creates a new record if one doesn't yet exist
394  */
395 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
396 {
397 	struct nfs_client *clp, *new = NULL;
398 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
399 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
400 
401 	if (cl_init->hostname == NULL) {
402 		WARN_ON(1);
403 		return NULL;
404 	}
405 
406 	/* see if the client already exists */
407 	do {
408 		spin_lock(&nn->nfs_client_lock);
409 
410 		clp = nfs_match_client(cl_init);
411 		if (clp) {
412 			spin_unlock(&nn->nfs_client_lock);
413 			if (IS_ERR(clp))
414 				return clp;
415 			if (new)
416 				new->rpc_ops->free_client(new);
417 			return nfs_found_client(cl_init, clp);
418 		}
419 		if (new) {
420 			list_add_tail(&new->cl_share_link,
421 					&nn->nfs_client_list);
422 			spin_unlock(&nn->nfs_client_lock);
423 			new->cl_flags = cl_init->init_flags;
424 			return rpc_ops->init_client(new, cl_init);
425 		}
426 
427 		spin_unlock(&nn->nfs_client_lock);
428 
429 		new = rpc_ops->alloc_client(cl_init);
430 	} while (!IS_ERR(new));
431 
432 	return new;
433 }
434 EXPORT_SYMBOL_GPL(nfs_get_client);
435 
436 /*
437  * Mark a server as ready or failed
438  */
439 void nfs_mark_client_ready(struct nfs_client *clp, int state)
440 {
441 	smp_wmb();
442 	clp->cl_cons_state = state;
443 	wake_up_all(&nfs_client_active_wq);
444 }
445 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
446 
447 /*
448  * Initialise the timeout values for a connection
449  */
450 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
451 				    int timeo, int retrans)
452 {
453 	to->to_initval = timeo * HZ / 10;
454 	to->to_retries = retrans;
455 
456 	switch (proto) {
457 	case XPRT_TRANSPORT_TCP:
458 	case XPRT_TRANSPORT_RDMA:
459 		if (retrans == NFS_UNSPEC_RETRANS)
460 			to->to_retries = NFS_DEF_TCP_RETRANS;
461 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
462 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
463 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
464 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
465 		to->to_increment = to->to_initval;
466 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
467 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
468 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
469 		if (to->to_maxval < to->to_initval)
470 			to->to_maxval = to->to_initval;
471 		to->to_exponential = 0;
472 		break;
473 	case XPRT_TRANSPORT_UDP:
474 		if (retrans == NFS_UNSPEC_RETRANS)
475 			to->to_retries = NFS_DEF_UDP_RETRANS;
476 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
477 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
478 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
479 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
480 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
481 		to->to_exponential = 1;
482 		break;
483 	default:
484 		BUG();
485 	}
486 }
487 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
488 
489 /*
490  * Create an RPC client handle
491  */
492 int nfs_create_rpc_client(struct nfs_client *clp,
493 			  const struct nfs_client_initdata *cl_init,
494 			  rpc_authflavor_t flavor)
495 {
496 	struct rpc_clnt		*clnt = NULL;
497 	struct rpc_create_args args = {
498 		.net		= clp->cl_net,
499 		.protocol	= clp->cl_proto,
500 		.address	= (struct sockaddr *)&clp->cl_addr,
501 		.addrsize	= clp->cl_addrlen,
502 		.timeout	= cl_init->timeparms,
503 		.servername	= clp->cl_hostname,
504 		.nodename	= cl_init->nodename,
505 		.program	= &nfs_program,
506 		.version	= clp->rpc_ops->version,
507 		.authflavor	= flavor,
508 		.cred		= cl_init->cred,
509 	};
510 
511 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
512 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
513 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
514 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
515 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
516 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
517 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
518 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
519 
520 	if (!IS_ERR(clp->cl_rpcclient))
521 		return 0;
522 
523 	clnt = rpc_create(&args);
524 	if (IS_ERR(clnt)) {
525 		dprintk("%s: cannot create RPC client. Error = %ld\n",
526 				__func__, PTR_ERR(clnt));
527 		return PTR_ERR(clnt);
528 	}
529 
530 	clnt->cl_principal = clp->cl_principal;
531 	clp->cl_rpcclient = clnt;
532 	return 0;
533 }
534 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
535 
536 /*
537  * Version 2 or 3 client destruction
538  */
539 static void nfs_destroy_server(struct nfs_server *server)
540 {
541 	if (server->nlm_host)
542 		nlmclnt_done(server->nlm_host);
543 }
544 
545 /*
546  * Version 2 or 3 lockd setup
547  */
548 static int nfs_start_lockd(struct nfs_server *server)
549 {
550 	struct nlm_host *host;
551 	struct nfs_client *clp = server->nfs_client;
552 	struct nlmclnt_initdata nlm_init = {
553 		.hostname	= clp->cl_hostname,
554 		.address	= (struct sockaddr *)&clp->cl_addr,
555 		.addrlen	= clp->cl_addrlen,
556 		.nfs_version	= clp->rpc_ops->version,
557 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
558 					1 : 0,
559 		.net		= clp->cl_net,
560 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
561 	};
562 
563 	if (nlm_init.nfs_version > 3)
564 		return 0;
565 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
566 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
567 		return 0;
568 
569 	switch (clp->cl_proto) {
570 		default:
571 			nlm_init.protocol = IPPROTO_TCP;
572 			break;
573 		case XPRT_TRANSPORT_UDP:
574 			nlm_init.protocol = IPPROTO_UDP;
575 	}
576 
577 	host = nlmclnt_init(&nlm_init);
578 	if (IS_ERR(host))
579 		return PTR_ERR(host);
580 
581 	server->nlm_host = host;
582 	server->destroy = nfs_destroy_server;
583 	return 0;
584 }
585 
586 /*
587  * Create a general RPC client
588  */
589 int nfs_init_server_rpcclient(struct nfs_server *server,
590 		const struct rpc_timeout *timeo,
591 		rpc_authflavor_t pseudoflavour)
592 {
593 	struct nfs_client *clp = server->nfs_client;
594 
595 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
596 							pseudoflavour);
597 	if (IS_ERR(server->client)) {
598 		dprintk("%s: couldn't create rpc_client!\n", __func__);
599 		return PTR_ERR(server->client);
600 	}
601 
602 	memcpy(&server->client->cl_timeout_default,
603 			timeo,
604 			sizeof(server->client->cl_timeout_default));
605 	server->client->cl_timeout = &server->client->cl_timeout_default;
606 	server->client->cl_softrtry = 0;
607 	if (server->flags & NFS_MOUNT_SOFTERR)
608 		server->client->cl_softerr = 1;
609 	if (server->flags & NFS_MOUNT_SOFT)
610 		server->client->cl_softrtry = 1;
611 
612 	return 0;
613 }
614 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
615 
616 /**
617  * nfs_init_client - Initialise an NFS2 or NFS3 client
618  *
619  * @clp: nfs_client to initialise
620  * @cl_init: Initialisation parameters
621  *
622  * Returns pointer to an NFS client, or an ERR_PTR value.
623  */
624 struct nfs_client *nfs_init_client(struct nfs_client *clp,
625 				   const struct nfs_client_initdata *cl_init)
626 {
627 	int error;
628 
629 	/* the client is already initialised */
630 	if (clp->cl_cons_state == NFS_CS_READY)
631 		return clp;
632 
633 	/*
634 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
635 	 * - RFC 2623, sec 2.3.2
636 	 */
637 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
638 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
639 	if (error < 0) {
640 		nfs_put_client(clp);
641 		clp = ERR_PTR(error);
642 	}
643 	return clp;
644 }
645 EXPORT_SYMBOL_GPL(nfs_init_client);
646 
647 /*
648  * Create a version 2 or 3 client
649  */
650 static int nfs_init_server(struct nfs_server *server,
651 			   const struct nfs_parsed_mount_data *data,
652 			   struct nfs_subversion *nfs_mod)
653 {
654 	struct rpc_timeout timeparms;
655 	struct nfs_client_initdata cl_init = {
656 		.hostname = data->nfs_server.hostname,
657 		.addr = (const struct sockaddr *)&data->nfs_server.address,
658 		.addrlen = data->nfs_server.addrlen,
659 		.nfs_mod = nfs_mod,
660 		.proto = data->nfs_server.protocol,
661 		.net = data->net,
662 		.timeparms = &timeparms,
663 		.cred = server->cred,
664 	};
665 	struct nfs_client *clp;
666 	int error;
667 
668 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
669 			data->timeo, data->retrans);
670 	if (data->flags & NFS_MOUNT_NORESVPORT)
671 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
672 
673 	/* Allocate or find a client reference we can use */
674 	clp = nfs_get_client(&cl_init);
675 	if (IS_ERR(clp))
676 		return PTR_ERR(clp);
677 
678 	server->nfs_client = clp;
679 
680 	/* Initialise the client representation from the mount data */
681 	server->flags = data->flags;
682 	server->options = data->options;
683 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
684 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
685 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
686 
687 	if (data->rsize)
688 		server->rsize = nfs_block_size(data->rsize, NULL);
689 	if (data->wsize)
690 		server->wsize = nfs_block_size(data->wsize, NULL);
691 
692 	server->acregmin = data->acregmin * HZ;
693 	server->acregmax = data->acregmax * HZ;
694 	server->acdirmin = data->acdirmin * HZ;
695 	server->acdirmax = data->acdirmax * HZ;
696 
697 	/* Start lockd here, before we might error out */
698 	error = nfs_start_lockd(server);
699 	if (error < 0)
700 		goto error;
701 
702 	server->port = data->nfs_server.port;
703 	server->auth_info = data->auth_info;
704 
705 	error = nfs_init_server_rpcclient(server, &timeparms,
706 					  data->selected_flavor);
707 	if (error < 0)
708 		goto error;
709 
710 	/* Preserve the values of mount_server-related mount options */
711 	if (data->mount_server.addrlen) {
712 		memcpy(&server->mountd_address, &data->mount_server.address,
713 			data->mount_server.addrlen);
714 		server->mountd_addrlen = data->mount_server.addrlen;
715 	}
716 	server->mountd_version = data->mount_server.version;
717 	server->mountd_port = data->mount_server.port;
718 	server->mountd_protocol = data->mount_server.protocol;
719 
720 	server->namelen  = data->namlen;
721 	return 0;
722 
723 error:
724 	server->nfs_client = NULL;
725 	nfs_put_client(clp);
726 	return error;
727 }
728 
729 /*
730  * Load up the server record from information gained in an fsinfo record
731  */
732 static void nfs_server_set_fsinfo(struct nfs_server *server,
733 				  struct nfs_fsinfo *fsinfo)
734 {
735 	unsigned long max_rpc_payload;
736 
737 	/* Work out a lot of parameters */
738 	if (server->rsize == 0)
739 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
740 	if (server->wsize == 0)
741 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
742 
743 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
744 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
745 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
746 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
747 
748 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
749 	if (server->rsize > max_rpc_payload)
750 		server->rsize = max_rpc_payload;
751 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
752 		server->rsize = NFS_MAX_FILE_IO_SIZE;
753 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
754 
755 	if (server->wsize > max_rpc_payload)
756 		server->wsize = max_rpc_payload;
757 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
758 		server->wsize = NFS_MAX_FILE_IO_SIZE;
759 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
760 
761 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
762 
763 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
764 	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
765 		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
766 	if (server->dtsize > server->rsize)
767 		server->dtsize = server->rsize;
768 
769 	if (server->flags & NFS_MOUNT_NOAC) {
770 		server->acregmin = server->acregmax = 0;
771 		server->acdirmin = server->acdirmax = 0;
772 	}
773 
774 	server->maxfilesize = fsinfo->maxfilesize;
775 
776 	server->time_delta = fsinfo->time_delta;
777 
778 	server->clone_blksize = fsinfo->clone_blksize;
779 	/* We're airborne Set socket buffersize */
780 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
781 }
782 
783 /*
784  * Probe filesystem information, including the FSID on v2/v3
785  */
786 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
787 {
788 	struct nfs_fsinfo fsinfo;
789 	struct nfs_client *clp = server->nfs_client;
790 	int error;
791 
792 	if (clp->rpc_ops->set_capabilities != NULL) {
793 		error = clp->rpc_ops->set_capabilities(server, mntfh);
794 		if (error < 0)
795 			return error;
796 	}
797 
798 	fsinfo.fattr = fattr;
799 	fsinfo.nlayouttypes = 0;
800 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
801 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
802 	if (error < 0)
803 		return error;
804 
805 	nfs_server_set_fsinfo(server, &fsinfo);
806 
807 	/* Get some general file system info */
808 	if (server->namelen == 0) {
809 		struct nfs_pathconf pathinfo;
810 
811 		pathinfo.fattr = fattr;
812 		nfs_fattr_init(fattr);
813 
814 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
815 			server->namelen = pathinfo.max_namelen;
816 	}
817 
818 	return 0;
819 }
820 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
821 
822 /*
823  * Copy useful information when duplicating a server record
824  */
825 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
826 {
827 	target->flags = source->flags;
828 	target->rsize = source->rsize;
829 	target->wsize = source->wsize;
830 	target->acregmin = source->acregmin;
831 	target->acregmax = source->acregmax;
832 	target->acdirmin = source->acdirmin;
833 	target->acdirmax = source->acdirmax;
834 	target->caps = source->caps;
835 	target->options = source->options;
836 	target->auth_info = source->auth_info;
837 	target->port = source->port;
838 }
839 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
840 
841 void nfs_server_insert_lists(struct nfs_server *server)
842 {
843 	struct nfs_client *clp = server->nfs_client;
844 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
845 
846 	spin_lock(&nn->nfs_client_lock);
847 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
848 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
849 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
850 	spin_unlock(&nn->nfs_client_lock);
851 
852 }
853 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
854 
855 void nfs_server_remove_lists(struct nfs_server *server)
856 {
857 	struct nfs_client *clp = server->nfs_client;
858 	struct nfs_net *nn;
859 
860 	if (clp == NULL)
861 		return;
862 	nn = net_generic(clp->cl_net, nfs_net_id);
863 	spin_lock(&nn->nfs_client_lock);
864 	list_del_rcu(&server->client_link);
865 	if (list_empty(&clp->cl_superblocks))
866 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
867 	list_del(&server->master_link);
868 	spin_unlock(&nn->nfs_client_lock);
869 
870 	synchronize_rcu();
871 }
872 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
873 
874 /*
875  * Allocate and initialise a server record
876  */
877 struct nfs_server *nfs_alloc_server(void)
878 {
879 	struct nfs_server *server;
880 
881 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
882 	if (!server)
883 		return NULL;
884 
885 	server->client = server->client_acl = ERR_PTR(-EINVAL);
886 
887 	/* Zero out the NFS state stuff */
888 	INIT_LIST_HEAD(&server->client_link);
889 	INIT_LIST_HEAD(&server->master_link);
890 	INIT_LIST_HEAD(&server->delegations);
891 	INIT_LIST_HEAD(&server->layouts);
892 	INIT_LIST_HEAD(&server->state_owners_lru);
893 	INIT_LIST_HEAD(&server->ss_copies);
894 
895 	atomic_set(&server->active, 0);
896 
897 	server->io_stats = nfs_alloc_iostats();
898 	if (!server->io_stats) {
899 		kfree(server);
900 		return NULL;
901 	}
902 
903 	ida_init(&server->openowner_id);
904 	ida_init(&server->lockowner_id);
905 	pnfs_init_server(server);
906 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
907 
908 	return server;
909 }
910 EXPORT_SYMBOL_GPL(nfs_alloc_server);
911 
912 /*
913  * Free up a server record
914  */
915 void nfs_free_server(struct nfs_server *server)
916 {
917 	nfs_server_remove_lists(server);
918 
919 	if (server->destroy != NULL)
920 		server->destroy(server);
921 
922 	if (!IS_ERR(server->client_acl))
923 		rpc_shutdown_client(server->client_acl);
924 	if (!IS_ERR(server->client))
925 		rpc_shutdown_client(server->client);
926 
927 	nfs_put_client(server->nfs_client);
928 
929 	ida_destroy(&server->lockowner_id);
930 	ida_destroy(&server->openowner_id);
931 	nfs_free_iostats(server->io_stats);
932 	put_cred(server->cred);
933 	kfree(server);
934 	nfs_release_automount_timer();
935 }
936 EXPORT_SYMBOL_GPL(nfs_free_server);
937 
938 /*
939  * Create a version 2 or 3 volume record
940  * - keyed on server and FSID
941  */
942 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
943 				     struct nfs_subversion *nfs_mod)
944 {
945 	struct nfs_server *server;
946 	struct nfs_fattr *fattr;
947 	int error;
948 
949 	server = nfs_alloc_server();
950 	if (!server)
951 		return ERR_PTR(-ENOMEM);
952 
953 	server->cred = get_cred(current_cred());
954 
955 	error = -ENOMEM;
956 	fattr = nfs_alloc_fattr();
957 	if (fattr == NULL)
958 		goto error;
959 
960 	/* Get a client representation */
961 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
962 	if (error < 0)
963 		goto error;
964 
965 	/* Probe the root fh to retrieve its FSID */
966 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
967 	if (error < 0)
968 		goto error;
969 	if (server->nfs_client->rpc_ops->version == 3) {
970 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
971 			server->namelen = NFS3_MAXNAMLEN;
972 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
973 			server->caps |= NFS_CAP_READDIRPLUS;
974 	} else {
975 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
976 			server->namelen = NFS2_MAXNAMLEN;
977 	}
978 
979 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
980 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh,
981 				fattr, NULL, NULL);
982 		if (error < 0) {
983 			dprintk("nfs_create_server: getattr error = %d\n", -error);
984 			goto error;
985 		}
986 	}
987 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
988 
989 	dprintk("Server FSID: %llx:%llx\n",
990 		(unsigned long long) server->fsid.major,
991 		(unsigned long long) server->fsid.minor);
992 
993 	nfs_server_insert_lists(server);
994 	server->mount_time = jiffies;
995 	nfs_free_fattr(fattr);
996 	return server;
997 
998 error:
999 	nfs_free_fattr(fattr);
1000 	nfs_free_server(server);
1001 	return ERR_PTR(error);
1002 }
1003 EXPORT_SYMBOL_GPL(nfs_create_server);
1004 
1005 /*
1006  * Clone an NFS2, NFS3 or NFS4 server record
1007  */
1008 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1009 				    struct nfs_fh *fh,
1010 				    struct nfs_fattr *fattr,
1011 				    rpc_authflavor_t flavor)
1012 {
1013 	struct nfs_server *server;
1014 	struct nfs_fattr *fattr_fsinfo;
1015 	int error;
1016 
1017 	server = nfs_alloc_server();
1018 	if (!server)
1019 		return ERR_PTR(-ENOMEM);
1020 
1021 	server->cred = get_cred(source->cred);
1022 
1023 	error = -ENOMEM;
1024 	fattr_fsinfo = nfs_alloc_fattr();
1025 	if (fattr_fsinfo == NULL)
1026 		goto out_free_server;
1027 
1028 	/* Copy data from the source */
1029 	server->nfs_client = source->nfs_client;
1030 	server->destroy = source->destroy;
1031 	refcount_inc(&server->nfs_client->cl_count);
1032 	nfs_server_copy_userdata(server, source);
1033 
1034 	server->fsid = fattr->fsid;
1035 
1036 	error = nfs_init_server_rpcclient(server,
1037 			source->client->cl_timeout,
1038 			flavor);
1039 	if (error < 0)
1040 		goto out_free_server;
1041 
1042 	/* probe the filesystem info for this server filesystem */
1043 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1044 	if (error < 0)
1045 		goto out_free_server;
1046 
1047 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1048 		server->namelen = NFS4_MAXNAMLEN;
1049 
1050 	error = nfs_start_lockd(server);
1051 	if (error < 0)
1052 		goto out_free_server;
1053 
1054 	nfs_server_insert_lists(server);
1055 	server->mount_time = jiffies;
1056 
1057 	nfs_free_fattr(fattr_fsinfo);
1058 	return server;
1059 
1060 out_free_server:
1061 	nfs_free_fattr(fattr_fsinfo);
1062 	nfs_free_server(server);
1063 	return ERR_PTR(error);
1064 }
1065 EXPORT_SYMBOL_GPL(nfs_clone_server);
1066 
1067 void nfs_clients_init(struct net *net)
1068 {
1069 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1070 
1071 	INIT_LIST_HEAD(&nn->nfs_client_list);
1072 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1073 #if IS_ENABLED(CONFIG_NFS_V4)
1074 	idr_init(&nn->cb_ident_idr);
1075 #endif
1076 	spin_lock_init(&nn->nfs_client_lock);
1077 	nn->boot_time = ktime_get_real();
1078 }
1079 
1080 #ifdef CONFIG_PROC_FS
1081 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1082 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1083 static void nfs_server_list_stop(struct seq_file *p, void *v);
1084 static int nfs_server_list_show(struct seq_file *m, void *v);
1085 
1086 static const struct seq_operations nfs_server_list_ops = {
1087 	.start	= nfs_server_list_start,
1088 	.next	= nfs_server_list_next,
1089 	.stop	= nfs_server_list_stop,
1090 	.show	= nfs_server_list_show,
1091 };
1092 
1093 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1094 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1095 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1096 static int nfs_volume_list_show(struct seq_file *m, void *v);
1097 
1098 static const struct seq_operations nfs_volume_list_ops = {
1099 	.start	= nfs_volume_list_start,
1100 	.next	= nfs_volume_list_next,
1101 	.stop	= nfs_volume_list_stop,
1102 	.show	= nfs_volume_list_show,
1103 };
1104 
1105 /*
1106  * set up the iterator to start reading from the server list and return the first item
1107  */
1108 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1109 				__acquires(&nn->nfs_client_lock)
1110 {
1111 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1112 
1113 	/* lock the list against modification */
1114 	spin_lock(&nn->nfs_client_lock);
1115 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1116 }
1117 
1118 /*
1119  * move to next server
1120  */
1121 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1122 {
1123 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1124 
1125 	return seq_list_next(v, &nn->nfs_client_list, pos);
1126 }
1127 
1128 /*
1129  * clean up after reading from the transports list
1130  */
1131 static void nfs_server_list_stop(struct seq_file *p, void *v)
1132 				__releases(&nn->nfs_client_lock)
1133 {
1134 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1135 
1136 	spin_unlock(&nn->nfs_client_lock);
1137 }
1138 
1139 /*
1140  * display a header line followed by a load of call lines
1141  */
1142 static int nfs_server_list_show(struct seq_file *m, void *v)
1143 {
1144 	struct nfs_client *clp;
1145 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1146 
1147 	/* display header on line 1 */
1148 	if (v == &nn->nfs_client_list) {
1149 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1150 		return 0;
1151 	}
1152 
1153 	/* display one transport per line on subsequent lines */
1154 	clp = list_entry(v, struct nfs_client, cl_share_link);
1155 
1156 	/* Check if the client is initialized */
1157 	if (clp->cl_cons_state != NFS_CS_READY)
1158 		return 0;
1159 
1160 	rcu_read_lock();
1161 	seq_printf(m, "v%u %s %s %3d %s\n",
1162 		   clp->rpc_ops->version,
1163 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1164 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1165 		   refcount_read(&clp->cl_count),
1166 		   clp->cl_hostname);
1167 	rcu_read_unlock();
1168 
1169 	return 0;
1170 }
1171 
1172 /*
1173  * set up the iterator to start reading from the volume list and return the first item
1174  */
1175 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1176 				__acquires(&nn->nfs_client_lock)
1177 {
1178 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1179 
1180 	/* lock the list against modification */
1181 	spin_lock(&nn->nfs_client_lock);
1182 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1183 }
1184 
1185 /*
1186  * move to next volume
1187  */
1188 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1189 {
1190 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1191 
1192 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1193 }
1194 
1195 /*
1196  * clean up after reading from the transports list
1197  */
1198 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1199 				__releases(&nn->nfs_client_lock)
1200 {
1201 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1202 
1203 	spin_unlock(&nn->nfs_client_lock);
1204 }
1205 
1206 /*
1207  * display a header line followed by a load of call lines
1208  */
1209 static int nfs_volume_list_show(struct seq_file *m, void *v)
1210 {
1211 	struct nfs_server *server;
1212 	struct nfs_client *clp;
1213 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1214 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1215 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1216 
1217 	/* display header on line 1 */
1218 	if (v == &nn->nfs_volume_list) {
1219 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1220 			    "                              FSC\n");
1221 		return 0;
1222 	}
1223 	/* display one transport per line on subsequent lines */
1224 	server = list_entry(v, struct nfs_server, master_link);
1225 	clp = server->nfs_client;
1226 
1227 	snprintf(dev, sizeof(dev), "%u:%u",
1228 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1229 
1230 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1231 		 (unsigned long long) server->fsid.major,
1232 		 (unsigned long long) server->fsid.minor);
1233 
1234 	rcu_read_lock();
1235 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1236 		   clp->rpc_ops->version,
1237 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1238 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1239 		   dev,
1240 		   fsid,
1241 		   nfs_server_fscache_state(server));
1242 	rcu_read_unlock();
1243 
1244 	return 0;
1245 }
1246 
1247 int nfs_fs_proc_net_init(struct net *net)
1248 {
1249 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1250 	struct proc_dir_entry *p;
1251 
1252 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1253 	if (!nn->proc_nfsfs)
1254 		goto error_0;
1255 
1256 	/* a file of servers with which we're dealing */
1257 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1258 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1259 	if (!p)
1260 		goto error_1;
1261 
1262 	/* a file of volumes that we have mounted */
1263 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1264 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1265 	if (!p)
1266 		goto error_1;
1267 	return 0;
1268 
1269 error_1:
1270 	remove_proc_subtree("nfsfs", net->proc_net);
1271 error_0:
1272 	return -ENOMEM;
1273 }
1274 
1275 void nfs_fs_proc_net_exit(struct net *net)
1276 {
1277 	remove_proc_subtree("nfsfs", net->proc_net);
1278 }
1279 
1280 /*
1281  * initialise the /proc/fs/nfsfs/ directory
1282  */
1283 int __init nfs_fs_proc_init(void)
1284 {
1285 	if (!proc_mkdir("fs/nfsfs", NULL))
1286 		goto error_0;
1287 
1288 	/* a file of servers with which we're dealing */
1289 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1290 		goto error_1;
1291 
1292 	/* a file of volumes that we have mounted */
1293 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1294 		goto error_1;
1295 
1296 	return 0;
1297 error_1:
1298 	remove_proc_subtree("fs/nfsfs", NULL);
1299 error_0:
1300 	return -ENOMEM;
1301 }
1302 
1303 /*
1304  * clean up the /proc/fs/nfsfs/ directory
1305  */
1306 void nfs_fs_proc_exit(void)
1307 {
1308 	remove_proc_subtree("fs/nfsfs", NULL);
1309 }
1310 
1311 #endif /* CONFIG_PROC_FS */
1312