xref: /openbmc/linux/fs/nfs/client.c (revision 2cf1c348)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* client.c: NFS client sharing and management code
3  *
4  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/sched.h>
12 #include <linux/time.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/string.h>
16 #include <linux/stat.h>
17 #include <linux/errno.h>
18 #include <linux/unistd.h>
19 #include <linux/sunrpc/addr.h>
20 #include <linux/sunrpc/clnt.h>
21 #include <linux/sunrpc/stats.h>
22 #include <linux/sunrpc/metrics.h>
23 #include <linux/sunrpc/xprtsock.h>
24 #include <linux/sunrpc/xprtrdma.h>
25 #include <linux/nfs_fs.h>
26 #include <linux/nfs_mount.h>
27 #include <linux/nfs4_mount.h>
28 #include <linux/lockd/bind.h>
29 #include <linux/seq_file.h>
30 #include <linux/mount.h>
31 #include <linux/vfs.h>
32 #include <linux/inet.h>
33 #include <linux/in6.h>
34 #include <linux/slab.h>
35 #include <linux/idr.h>
36 #include <net/ipv6.h>
37 #include <linux/nfs_xdr.h>
38 #include <linux/sunrpc/bc_xprt.h>
39 #include <linux/nsproxy.h>
40 #include <linux/pid_namespace.h>
41 
42 
43 #include "nfs4_fs.h"
44 #include "callback.h"
45 #include "delegation.h"
46 #include "iostat.h"
47 #include "internal.h"
48 #include "fscache.h"
49 #include "pnfs.h"
50 #include "nfs.h"
51 #include "netns.h"
52 #include "sysfs.h"
53 #include "nfs42.h"
54 
55 #define NFSDBG_FACILITY		NFSDBG_CLIENT
56 
57 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
58 static DEFINE_SPINLOCK(nfs_version_lock);
59 static DEFINE_MUTEX(nfs_version_mutex);
60 static LIST_HEAD(nfs_versions);
61 
62 /*
63  * RPC cruft for NFS
64  */
65 static const struct rpc_version *nfs_version[5] = {
66 	[2] = NULL,
67 	[3] = NULL,
68 	[4] = NULL,
69 };
70 
71 const struct rpc_program nfs_program = {
72 	.name			= "nfs",
73 	.number			= NFS_PROGRAM,
74 	.nrvers			= ARRAY_SIZE(nfs_version),
75 	.version		= nfs_version,
76 	.stats			= &nfs_rpcstat,
77 	.pipe_dir_name		= NFS_PIPE_DIRNAME,
78 };
79 
80 struct rpc_stat nfs_rpcstat = {
81 	.program		= &nfs_program
82 };
83 
84 static struct nfs_subversion *find_nfs_version(unsigned int version)
85 {
86 	struct nfs_subversion *nfs;
87 	spin_lock(&nfs_version_lock);
88 
89 	list_for_each_entry(nfs, &nfs_versions, list) {
90 		if (nfs->rpc_ops->version == version) {
91 			spin_unlock(&nfs_version_lock);
92 			return nfs;
93 		}
94 	}
95 
96 	spin_unlock(&nfs_version_lock);
97 	return ERR_PTR(-EPROTONOSUPPORT);
98 }
99 
100 struct nfs_subversion *get_nfs_version(unsigned int version)
101 {
102 	struct nfs_subversion *nfs = find_nfs_version(version);
103 
104 	if (IS_ERR(nfs)) {
105 		mutex_lock(&nfs_version_mutex);
106 		request_module("nfsv%d", version);
107 		nfs = find_nfs_version(version);
108 		mutex_unlock(&nfs_version_mutex);
109 	}
110 
111 	if (!IS_ERR(nfs) && !try_module_get(nfs->owner))
112 		return ERR_PTR(-EAGAIN);
113 	return nfs;
114 }
115 
116 void put_nfs_version(struct nfs_subversion *nfs)
117 {
118 	module_put(nfs->owner);
119 }
120 
121 void register_nfs_version(struct nfs_subversion *nfs)
122 {
123 	spin_lock(&nfs_version_lock);
124 
125 	list_add(&nfs->list, &nfs_versions);
126 	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
127 
128 	spin_unlock(&nfs_version_lock);
129 }
130 EXPORT_SYMBOL_GPL(register_nfs_version);
131 
132 void unregister_nfs_version(struct nfs_subversion *nfs)
133 {
134 	spin_lock(&nfs_version_lock);
135 
136 	nfs_version[nfs->rpc_ops->version] = NULL;
137 	list_del(&nfs->list);
138 
139 	spin_unlock(&nfs_version_lock);
140 }
141 EXPORT_SYMBOL_GPL(unregister_nfs_version);
142 
143 /*
144  * Allocate a shared client record
145  *
146  * Since these are allocated/deallocated very rarely, we don't
147  * bother putting them in a slab cache...
148  */
149 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
150 {
151 	struct nfs_client *clp;
152 	int err = -ENOMEM;
153 
154 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
155 		goto error_0;
156 
157 	clp->cl_minorversion = cl_init->minorversion;
158 	clp->cl_nfs_mod = cl_init->nfs_mod;
159 	if (!try_module_get(clp->cl_nfs_mod->owner))
160 		goto error_dealloc;
161 
162 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
163 
164 	refcount_set(&clp->cl_count, 1);
165 	clp->cl_cons_state = NFS_CS_INITING;
166 
167 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
168 	clp->cl_addrlen = cl_init->addrlen;
169 
170 	if (cl_init->hostname) {
171 		err = -ENOMEM;
172 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
173 		if (!clp->cl_hostname)
174 			goto error_cleanup;
175 	}
176 
177 	INIT_LIST_HEAD(&clp->cl_superblocks);
178 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
179 
180 	clp->cl_proto = cl_init->proto;
181 	clp->cl_nconnect = cl_init->nconnect;
182 	clp->cl_max_connect = cl_init->max_connect ? cl_init->max_connect : 1;
183 	clp->cl_net = get_net(cl_init->net);
184 
185 	clp->cl_principal = "*";
186 	return clp;
187 
188 error_cleanup:
189 	put_nfs_version(clp->cl_nfs_mod);
190 error_dealloc:
191 	kfree(clp);
192 error_0:
193 	return ERR_PTR(err);
194 }
195 EXPORT_SYMBOL_GPL(nfs_alloc_client);
196 
197 #if IS_ENABLED(CONFIG_NFS_V4)
198 static void nfs_cleanup_cb_ident_idr(struct net *net)
199 {
200 	struct nfs_net *nn = net_generic(net, nfs_net_id);
201 
202 	idr_destroy(&nn->cb_ident_idr);
203 }
204 
205 /* nfs_client_lock held */
206 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
207 {
208 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
209 
210 	if (clp->cl_cb_ident)
211 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
212 }
213 
214 static void pnfs_init_server(struct nfs_server *server)
215 {
216 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
217 }
218 
219 #else
220 static void nfs_cleanup_cb_ident_idr(struct net *net)
221 {
222 }
223 
224 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
225 {
226 }
227 
228 static void pnfs_init_server(struct nfs_server *server)
229 {
230 }
231 
232 #endif /* CONFIG_NFS_V4 */
233 
234 /*
235  * Destroy a shared client record
236  */
237 void nfs_free_client(struct nfs_client *clp)
238 {
239 	/* -EIO all pending I/O */
240 	if (!IS_ERR(clp->cl_rpcclient))
241 		rpc_shutdown_client(clp->cl_rpcclient);
242 
243 	put_net(clp->cl_net);
244 	put_nfs_version(clp->cl_nfs_mod);
245 	kfree(clp->cl_hostname);
246 	kfree(clp->cl_acceptor);
247 	kfree(clp);
248 }
249 EXPORT_SYMBOL_GPL(nfs_free_client);
250 
251 /*
252  * Release a reference to a shared client record
253  */
254 void nfs_put_client(struct nfs_client *clp)
255 {
256 	struct nfs_net *nn;
257 
258 	if (!clp)
259 		return;
260 
261 	nn = net_generic(clp->cl_net, nfs_net_id);
262 
263 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
264 		list_del(&clp->cl_share_link);
265 		nfs_cb_idr_remove_locked(clp);
266 		spin_unlock(&nn->nfs_client_lock);
267 
268 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
269 
270 		clp->rpc_ops->free_client(clp);
271 	}
272 }
273 EXPORT_SYMBOL_GPL(nfs_put_client);
274 
275 /*
276  * Find an nfs_client on the list that matches the initialisation data
277  * that is supplied.
278  */
279 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
280 {
281 	struct nfs_client *clp;
282 	const struct sockaddr *sap = data->addr;
283 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
284 	int error;
285 
286 again:
287 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
288 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
289 		/* Don't match clients that failed to initialise properly */
290 		if (clp->cl_cons_state < 0)
291 			continue;
292 
293 		/* If a client is still initializing then we need to wait */
294 		if (clp->cl_cons_state > NFS_CS_READY) {
295 			refcount_inc(&clp->cl_count);
296 			spin_unlock(&nn->nfs_client_lock);
297 			error = nfs_wait_client_init_complete(clp);
298 			nfs_put_client(clp);
299 			spin_lock(&nn->nfs_client_lock);
300 			if (error < 0)
301 				return ERR_PTR(error);
302 			goto again;
303 		}
304 
305 		/* Different NFS versions cannot share the same nfs_client */
306 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
307 			continue;
308 
309 		if (clp->cl_proto != data->proto)
310 			continue;
311 		/* Match nfsv4 minorversion */
312 		if (clp->cl_minorversion != data->minorversion)
313 			continue;
314 
315 		/* Match request for a dedicated DS */
316 		if (test_bit(NFS_CS_DS, &data->init_flags) !=
317 		    test_bit(NFS_CS_DS, &clp->cl_flags))
318 			continue;
319 
320 		/* Match the full socket address */
321 		if (!rpc_cmp_addr_port(sap, clap))
322 			/* Match all xprt_switch full socket addresses */
323 			if (IS_ERR(clp->cl_rpcclient) ||
324                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
325 							   sap))
326 				continue;
327 
328 		refcount_inc(&clp->cl_count);
329 		return clp;
330 	}
331 	return NULL;
332 }
333 
334 /*
335  * Return true if @clp is done initializing, false if still working on it.
336  *
337  * Use nfs_client_init_status to check if it was successful.
338  */
339 bool nfs_client_init_is_complete(const struct nfs_client *clp)
340 {
341 	return clp->cl_cons_state <= NFS_CS_READY;
342 }
343 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
344 
345 /*
346  * Return 0 if @clp was successfully initialized, -errno otherwise.
347  *
348  * This must be called *after* nfs_client_init_is_complete() returns true,
349  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
350  */
351 int nfs_client_init_status(const struct nfs_client *clp)
352 {
353 	/* called without checking nfs_client_init_is_complete */
354 	if (clp->cl_cons_state > NFS_CS_READY) {
355 		WARN_ON_ONCE(1);
356 		return -EINVAL;
357 	}
358 	return clp->cl_cons_state;
359 }
360 EXPORT_SYMBOL_GPL(nfs_client_init_status);
361 
362 int nfs_wait_client_init_complete(const struct nfs_client *clp)
363 {
364 	return wait_event_killable(nfs_client_active_wq,
365 			nfs_client_init_is_complete(clp));
366 }
367 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
368 
369 /*
370  * Found an existing client.  Make sure it's ready before returning.
371  */
372 static struct nfs_client *
373 nfs_found_client(const struct nfs_client_initdata *cl_init,
374 		 struct nfs_client *clp)
375 {
376 	int error;
377 
378 	error = nfs_wait_client_init_complete(clp);
379 	if (error < 0) {
380 		nfs_put_client(clp);
381 		return ERR_PTR(-ERESTARTSYS);
382 	}
383 
384 	if (clp->cl_cons_state < NFS_CS_READY) {
385 		error = clp->cl_cons_state;
386 		nfs_put_client(clp);
387 		return ERR_PTR(error);
388 	}
389 
390 	smp_rmb();
391 	return clp;
392 }
393 
394 /*
395  * Look up a client by IP address and protocol version
396  * - creates a new record if one doesn't yet exist
397  */
398 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
399 {
400 	struct nfs_client *clp, *new = NULL;
401 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
402 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
403 
404 	if (cl_init->hostname == NULL) {
405 		WARN_ON(1);
406 		return ERR_PTR(-EINVAL);
407 	}
408 
409 	/* see if the client already exists */
410 	do {
411 		spin_lock(&nn->nfs_client_lock);
412 
413 		clp = nfs_match_client(cl_init);
414 		if (clp) {
415 			spin_unlock(&nn->nfs_client_lock);
416 			if (new)
417 				new->rpc_ops->free_client(new);
418 			if (IS_ERR(clp))
419 				return clp;
420 			return nfs_found_client(cl_init, clp);
421 		}
422 		if (new) {
423 			list_add_tail(&new->cl_share_link,
424 					&nn->nfs_client_list);
425 			spin_unlock(&nn->nfs_client_lock);
426 			new->cl_flags = cl_init->init_flags;
427 			return rpc_ops->init_client(new, cl_init);
428 		}
429 
430 		spin_unlock(&nn->nfs_client_lock);
431 
432 		new = rpc_ops->alloc_client(cl_init);
433 	} while (!IS_ERR(new));
434 
435 	return new;
436 }
437 EXPORT_SYMBOL_GPL(nfs_get_client);
438 
439 /*
440  * Mark a server as ready or failed
441  */
442 void nfs_mark_client_ready(struct nfs_client *clp, int state)
443 {
444 	smp_wmb();
445 	clp->cl_cons_state = state;
446 	wake_up_all(&nfs_client_active_wq);
447 }
448 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
449 
450 /*
451  * Initialise the timeout values for a connection
452  */
453 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
454 				    int timeo, int retrans)
455 {
456 	to->to_initval = timeo * HZ / 10;
457 	to->to_retries = retrans;
458 
459 	switch (proto) {
460 	case XPRT_TRANSPORT_TCP:
461 	case XPRT_TRANSPORT_RDMA:
462 		if (retrans == NFS_UNSPEC_RETRANS)
463 			to->to_retries = NFS_DEF_TCP_RETRANS;
464 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
465 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
466 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
467 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
468 		to->to_increment = to->to_initval;
469 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
470 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
471 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
472 		if (to->to_maxval < to->to_initval)
473 			to->to_maxval = to->to_initval;
474 		to->to_exponential = 0;
475 		break;
476 	case XPRT_TRANSPORT_UDP:
477 		if (retrans == NFS_UNSPEC_RETRANS)
478 			to->to_retries = NFS_DEF_UDP_RETRANS;
479 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
480 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
481 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
482 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
483 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
484 		to->to_exponential = 1;
485 		break;
486 	default:
487 		BUG();
488 	}
489 }
490 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
491 
492 /*
493  * Create an RPC client handle
494  */
495 int nfs_create_rpc_client(struct nfs_client *clp,
496 			  const struct nfs_client_initdata *cl_init,
497 			  rpc_authflavor_t flavor)
498 {
499 	struct rpc_clnt		*clnt = NULL;
500 	struct rpc_create_args args = {
501 		.net		= clp->cl_net,
502 		.protocol	= clp->cl_proto,
503 		.nconnect	= clp->cl_nconnect,
504 		.address	= (struct sockaddr *)&clp->cl_addr,
505 		.addrsize	= clp->cl_addrlen,
506 		.timeout	= cl_init->timeparms,
507 		.servername	= clp->cl_hostname,
508 		.nodename	= cl_init->nodename,
509 		.program	= &nfs_program,
510 		.version	= clp->rpc_ops->version,
511 		.authflavor	= flavor,
512 		.cred		= cl_init->cred,
513 	};
514 
515 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
516 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
517 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
518 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
519 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
520 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
521 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
522 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
523 	if (test_bit(NFS_CS_NOPING, &clp->cl_flags))
524 		args.flags |= RPC_CLNT_CREATE_NOPING;
525 	if (test_bit(NFS_CS_REUSEPORT, &clp->cl_flags))
526 		args.flags |= RPC_CLNT_CREATE_REUSEPORT;
527 
528 	if (!IS_ERR(clp->cl_rpcclient))
529 		return 0;
530 
531 	clnt = rpc_create(&args);
532 	if (IS_ERR(clnt)) {
533 		dprintk("%s: cannot create RPC client. Error = %ld\n",
534 				__func__, PTR_ERR(clnt));
535 		return PTR_ERR(clnt);
536 	}
537 
538 	clnt->cl_principal = clp->cl_principal;
539 	clp->cl_rpcclient = clnt;
540 	clnt->cl_max_connect = clp->cl_max_connect;
541 	return 0;
542 }
543 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
544 
545 /*
546  * Version 2 or 3 client destruction
547  */
548 static void nfs_destroy_server(struct nfs_server *server)
549 {
550 	if (server->nlm_host)
551 		nlmclnt_done(server->nlm_host);
552 }
553 
554 /*
555  * Version 2 or 3 lockd setup
556  */
557 static int nfs_start_lockd(struct nfs_server *server)
558 {
559 	struct nlm_host *host;
560 	struct nfs_client *clp = server->nfs_client;
561 	struct nlmclnt_initdata nlm_init = {
562 		.hostname	= clp->cl_hostname,
563 		.address	= (struct sockaddr *)&clp->cl_addr,
564 		.addrlen	= clp->cl_addrlen,
565 		.nfs_version	= clp->rpc_ops->version,
566 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
567 					1 : 0,
568 		.net		= clp->cl_net,
569 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
570 		.cred		= server->cred,
571 	};
572 
573 	if (nlm_init.nfs_version > 3)
574 		return 0;
575 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
576 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
577 		return 0;
578 
579 	switch (clp->cl_proto) {
580 		default:
581 			nlm_init.protocol = IPPROTO_TCP;
582 			break;
583 #ifndef CONFIG_NFS_DISABLE_UDP_SUPPORT
584 		case XPRT_TRANSPORT_UDP:
585 			nlm_init.protocol = IPPROTO_UDP;
586 #endif
587 	}
588 
589 	host = nlmclnt_init(&nlm_init);
590 	if (IS_ERR(host))
591 		return PTR_ERR(host);
592 
593 	server->nlm_host = host;
594 	server->destroy = nfs_destroy_server;
595 	return 0;
596 }
597 
598 /*
599  * Create a general RPC client
600  */
601 int nfs_init_server_rpcclient(struct nfs_server *server,
602 		const struct rpc_timeout *timeo,
603 		rpc_authflavor_t pseudoflavour)
604 {
605 	struct nfs_client *clp = server->nfs_client;
606 
607 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
608 							pseudoflavour);
609 	if (IS_ERR(server->client)) {
610 		dprintk("%s: couldn't create rpc_client!\n", __func__);
611 		return PTR_ERR(server->client);
612 	}
613 
614 	memcpy(&server->client->cl_timeout_default,
615 			timeo,
616 			sizeof(server->client->cl_timeout_default));
617 	server->client->cl_timeout = &server->client->cl_timeout_default;
618 	server->client->cl_softrtry = 0;
619 	if (server->flags & NFS_MOUNT_SOFTERR)
620 		server->client->cl_softerr = 1;
621 	if (server->flags & NFS_MOUNT_SOFT)
622 		server->client->cl_softrtry = 1;
623 
624 	return 0;
625 }
626 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
627 
628 /**
629  * nfs_init_client - Initialise an NFS2 or NFS3 client
630  *
631  * @clp: nfs_client to initialise
632  * @cl_init: Initialisation parameters
633  *
634  * Returns pointer to an NFS client, or an ERR_PTR value.
635  */
636 struct nfs_client *nfs_init_client(struct nfs_client *clp,
637 				   const struct nfs_client_initdata *cl_init)
638 {
639 	int error;
640 
641 	/* the client is already initialised */
642 	if (clp->cl_cons_state == NFS_CS_READY)
643 		return clp;
644 
645 	/*
646 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
647 	 * - RFC 2623, sec 2.3.2
648 	 */
649 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
650 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
651 	if (error < 0) {
652 		nfs_put_client(clp);
653 		clp = ERR_PTR(error);
654 	}
655 	return clp;
656 }
657 EXPORT_SYMBOL_GPL(nfs_init_client);
658 
659 /*
660  * Create a version 2 or 3 client
661  */
662 static int nfs_init_server(struct nfs_server *server,
663 			   const struct fs_context *fc)
664 {
665 	const struct nfs_fs_context *ctx = nfs_fc2context(fc);
666 	struct rpc_timeout timeparms;
667 	struct nfs_client_initdata cl_init = {
668 		.hostname = ctx->nfs_server.hostname,
669 		.addr = (const struct sockaddr *)&ctx->nfs_server.address,
670 		.addrlen = ctx->nfs_server.addrlen,
671 		.nfs_mod = ctx->nfs_mod,
672 		.proto = ctx->nfs_server.protocol,
673 		.net = fc->net_ns,
674 		.timeparms = &timeparms,
675 		.cred = server->cred,
676 		.nconnect = ctx->nfs_server.nconnect,
677 		.init_flags = (1UL << NFS_CS_REUSEPORT),
678 	};
679 	struct nfs_client *clp;
680 	int error;
681 
682 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
683 				ctx->timeo, ctx->retrans);
684 	if (ctx->flags & NFS_MOUNT_NORESVPORT)
685 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
686 
687 	/* Allocate or find a client reference we can use */
688 	clp = nfs_get_client(&cl_init);
689 	if (IS_ERR(clp))
690 		return PTR_ERR(clp);
691 
692 	server->nfs_client = clp;
693 
694 	/* Initialise the client representation from the mount data */
695 	server->flags = ctx->flags;
696 	server->options = ctx->options;
697 	server->caps |= NFS_CAP_HARDLINKS | NFS_CAP_SYMLINKS;
698 
699 	switch (clp->rpc_ops->version) {
700 	case 2:
701 		server->fattr_valid = NFS_ATTR_FATTR_V2;
702 		break;
703 	case 3:
704 		server->fattr_valid = NFS_ATTR_FATTR_V3;
705 		break;
706 	default:
707 		server->fattr_valid = NFS_ATTR_FATTR_V4;
708 	}
709 
710 	if (ctx->rsize)
711 		server->rsize = nfs_block_size(ctx->rsize, NULL);
712 	if (ctx->wsize)
713 		server->wsize = nfs_block_size(ctx->wsize, NULL);
714 
715 	server->acregmin = ctx->acregmin * HZ;
716 	server->acregmax = ctx->acregmax * HZ;
717 	server->acdirmin = ctx->acdirmin * HZ;
718 	server->acdirmax = ctx->acdirmax * HZ;
719 
720 	/* Start lockd here, before we might error out */
721 	error = nfs_start_lockd(server);
722 	if (error < 0)
723 		goto error;
724 
725 	server->port = ctx->nfs_server.port;
726 	server->auth_info = ctx->auth_info;
727 
728 	error = nfs_init_server_rpcclient(server, &timeparms,
729 					  ctx->selected_flavor);
730 	if (error < 0)
731 		goto error;
732 
733 	/* Preserve the values of mount_server-related mount options */
734 	if (ctx->mount_server.addrlen) {
735 		memcpy(&server->mountd_address, &ctx->mount_server.address,
736 			ctx->mount_server.addrlen);
737 		server->mountd_addrlen = ctx->mount_server.addrlen;
738 	}
739 	server->mountd_version = ctx->mount_server.version;
740 	server->mountd_port = ctx->mount_server.port;
741 	server->mountd_protocol = ctx->mount_server.protocol;
742 
743 	server->namelen  = ctx->namlen;
744 	return 0;
745 
746 error:
747 	server->nfs_client = NULL;
748 	nfs_put_client(clp);
749 	return error;
750 }
751 
752 /*
753  * Load up the server record from information gained in an fsinfo record
754  */
755 static void nfs_server_set_fsinfo(struct nfs_server *server,
756 				  struct nfs_fsinfo *fsinfo)
757 {
758 	unsigned long max_rpc_payload, raw_max_rpc_payload;
759 
760 	/* Work out a lot of parameters */
761 	if (server->rsize == 0)
762 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
763 	if (server->wsize == 0)
764 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
765 
766 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
767 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
768 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
769 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
770 
771 	raw_max_rpc_payload = rpc_max_payload(server->client);
772 	max_rpc_payload = nfs_block_size(raw_max_rpc_payload, NULL);
773 
774 	if (server->rsize > max_rpc_payload)
775 		server->rsize = max_rpc_payload;
776 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
777 		server->rsize = NFS_MAX_FILE_IO_SIZE;
778 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
779 
780 	if (server->wsize > max_rpc_payload)
781 		server->wsize = max_rpc_payload;
782 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
783 		server->wsize = NFS_MAX_FILE_IO_SIZE;
784 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
785 
786 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
787 
788 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
789 	if (server->dtsize > NFS_MAX_FILE_IO_SIZE)
790 		server->dtsize = NFS_MAX_FILE_IO_SIZE;
791 	if (server->dtsize > server->rsize)
792 		server->dtsize = server->rsize;
793 
794 	if (server->flags & NFS_MOUNT_NOAC) {
795 		server->acregmin = server->acregmax = 0;
796 		server->acdirmin = server->acdirmax = 0;
797 	}
798 
799 	server->maxfilesize = fsinfo->maxfilesize;
800 
801 	server->time_delta = fsinfo->time_delta;
802 	server->change_attr_type = fsinfo->change_attr_type;
803 
804 	server->clone_blksize = fsinfo->clone_blksize;
805 	/* We're airborne Set socket buffersize */
806 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
807 
808 #ifdef CONFIG_NFS_V4_2
809 	/*
810 	 * Defaults until limited by the session parameters.
811 	 */
812 	server->gxasize = min_t(unsigned int, raw_max_rpc_payload,
813 				XATTR_SIZE_MAX);
814 	server->sxasize = min_t(unsigned int, raw_max_rpc_payload,
815 				XATTR_SIZE_MAX);
816 	server->lxasize = min_t(unsigned int, raw_max_rpc_payload,
817 				nfs42_listxattr_xdrsize(XATTR_LIST_MAX));
818 
819 	if (fsinfo->xattr_support)
820 		server->caps |= NFS_CAP_XATTR;
821 #endif
822 }
823 
824 /*
825  * Probe filesystem information, including the FSID on v2/v3
826  */
827 static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
828 {
829 	struct nfs_fsinfo fsinfo;
830 	struct nfs_client *clp = server->nfs_client;
831 	int error;
832 
833 	if (clp->rpc_ops->set_capabilities != NULL) {
834 		error = clp->rpc_ops->set_capabilities(server, mntfh);
835 		if (error < 0)
836 			return error;
837 	}
838 
839 	fsinfo.fattr = fattr;
840 	fsinfo.nlayouttypes = 0;
841 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
842 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
843 	if (error < 0)
844 		return error;
845 
846 	nfs_server_set_fsinfo(server, &fsinfo);
847 
848 	/* Get some general file system info */
849 	if (server->namelen == 0) {
850 		struct nfs_pathconf pathinfo;
851 
852 		pathinfo.fattr = fattr;
853 		nfs_fattr_init(fattr);
854 
855 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
856 			server->namelen = pathinfo.max_namelen;
857 	}
858 
859 	return 0;
860 }
861 
862 /*
863  * Grab the destination's particulars, including lease expiry time.
864  *
865  * Returns zero if probe succeeded and retrieved FSID matches the FSID
866  * we have cached.
867  */
868 int nfs_probe_server(struct nfs_server *server, struct nfs_fh *mntfh)
869 {
870 	struct nfs_fattr *fattr;
871 	int error;
872 
873 	fattr = nfs_alloc_fattr();
874 	if (fattr == NULL)
875 		return -ENOMEM;
876 
877 	/* Sanity: the probe won't work if the destination server
878 	 * does not recognize the migrated FH. */
879 	error = nfs_probe_fsinfo(server, mntfh, fattr);
880 
881 	nfs_free_fattr(fattr);
882 	return error;
883 }
884 EXPORT_SYMBOL_GPL(nfs_probe_server);
885 
886 /*
887  * Copy useful information when duplicating a server record
888  */
889 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
890 {
891 	target->flags = source->flags;
892 	target->rsize = source->rsize;
893 	target->wsize = source->wsize;
894 	target->acregmin = source->acregmin;
895 	target->acregmax = source->acregmax;
896 	target->acdirmin = source->acdirmin;
897 	target->acdirmax = source->acdirmax;
898 	target->caps = source->caps;
899 	target->options = source->options;
900 	target->auth_info = source->auth_info;
901 	target->port = source->port;
902 }
903 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
904 
905 void nfs_server_insert_lists(struct nfs_server *server)
906 {
907 	struct nfs_client *clp = server->nfs_client;
908 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
909 
910 	spin_lock(&nn->nfs_client_lock);
911 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
912 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
913 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
914 	spin_unlock(&nn->nfs_client_lock);
915 
916 }
917 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
918 
919 void nfs_server_remove_lists(struct nfs_server *server)
920 {
921 	struct nfs_client *clp = server->nfs_client;
922 	struct nfs_net *nn;
923 
924 	if (clp == NULL)
925 		return;
926 	nn = net_generic(clp->cl_net, nfs_net_id);
927 	spin_lock(&nn->nfs_client_lock);
928 	list_del_rcu(&server->client_link);
929 	if (list_empty(&clp->cl_superblocks))
930 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
931 	list_del(&server->master_link);
932 	spin_unlock(&nn->nfs_client_lock);
933 
934 	synchronize_rcu();
935 }
936 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
937 
938 /*
939  * Allocate and initialise a server record
940  */
941 struct nfs_server *nfs_alloc_server(void)
942 {
943 	struct nfs_server *server;
944 
945 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
946 	if (!server)
947 		return NULL;
948 
949 	server->client = server->client_acl = ERR_PTR(-EINVAL);
950 
951 	/* Zero out the NFS state stuff */
952 	INIT_LIST_HEAD(&server->client_link);
953 	INIT_LIST_HEAD(&server->master_link);
954 	INIT_LIST_HEAD(&server->delegations);
955 	INIT_LIST_HEAD(&server->layouts);
956 	INIT_LIST_HEAD(&server->state_owners_lru);
957 	INIT_LIST_HEAD(&server->ss_copies);
958 
959 	atomic_set(&server->active, 0);
960 
961 	server->io_stats = nfs_alloc_iostats();
962 	if (!server->io_stats) {
963 		kfree(server);
964 		return NULL;
965 	}
966 
967 	server->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
968 
969 	ida_init(&server->openowner_id);
970 	ida_init(&server->lockowner_id);
971 	pnfs_init_server(server);
972 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
973 
974 	return server;
975 }
976 EXPORT_SYMBOL_GPL(nfs_alloc_server);
977 
978 /*
979  * Free up a server record
980  */
981 void nfs_free_server(struct nfs_server *server)
982 {
983 	nfs_server_remove_lists(server);
984 
985 	if (server->destroy != NULL)
986 		server->destroy(server);
987 
988 	if (!IS_ERR(server->client_acl))
989 		rpc_shutdown_client(server->client_acl);
990 	if (!IS_ERR(server->client))
991 		rpc_shutdown_client(server->client);
992 
993 	nfs_put_client(server->nfs_client);
994 
995 	ida_destroy(&server->lockowner_id);
996 	ida_destroy(&server->openowner_id);
997 	nfs_free_iostats(server->io_stats);
998 	put_cred(server->cred);
999 	kfree(server);
1000 	nfs_release_automount_timer();
1001 }
1002 EXPORT_SYMBOL_GPL(nfs_free_server);
1003 
1004 /*
1005  * Create a version 2 or 3 volume record
1006  * - keyed on server and FSID
1007  */
1008 struct nfs_server *nfs_create_server(struct fs_context *fc)
1009 {
1010 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1011 	struct nfs_server *server;
1012 	struct nfs_fattr *fattr;
1013 	int error;
1014 
1015 	server = nfs_alloc_server();
1016 	if (!server)
1017 		return ERR_PTR(-ENOMEM);
1018 
1019 	server->cred = get_cred(fc->cred);
1020 
1021 	error = -ENOMEM;
1022 	fattr = nfs_alloc_fattr();
1023 	if (fattr == NULL)
1024 		goto error;
1025 
1026 	/* Get a client representation */
1027 	error = nfs_init_server(server, fc);
1028 	if (error < 0)
1029 		goto error;
1030 
1031 	/* Probe the root fh to retrieve its FSID */
1032 	error = nfs_probe_fsinfo(server, ctx->mntfh, fattr);
1033 	if (error < 0)
1034 		goto error;
1035 	if (server->nfs_client->rpc_ops->version == 3) {
1036 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
1037 			server->namelen = NFS3_MAXNAMLEN;
1038 		if (!(ctx->flags & NFS_MOUNT_NORDIRPLUS))
1039 			server->caps |= NFS_CAP_READDIRPLUS;
1040 	} else {
1041 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
1042 			server->namelen = NFS2_MAXNAMLEN;
1043 	}
1044 
1045 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
1046 		error = ctx->nfs_mod->rpc_ops->getattr(server, ctx->mntfh,
1047 						       fattr, NULL);
1048 		if (error < 0) {
1049 			dprintk("nfs_create_server: getattr error = %d\n", -error);
1050 			goto error;
1051 		}
1052 	}
1053 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
1054 
1055 	dprintk("Server FSID: %llx:%llx\n",
1056 		(unsigned long long) server->fsid.major,
1057 		(unsigned long long) server->fsid.minor);
1058 
1059 	nfs_server_insert_lists(server);
1060 	server->mount_time = jiffies;
1061 	nfs_free_fattr(fattr);
1062 	return server;
1063 
1064 error:
1065 	nfs_free_fattr(fattr);
1066 	nfs_free_server(server);
1067 	return ERR_PTR(error);
1068 }
1069 EXPORT_SYMBOL_GPL(nfs_create_server);
1070 
1071 /*
1072  * Clone an NFS2, NFS3 or NFS4 server record
1073  */
1074 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1075 				    struct nfs_fh *fh,
1076 				    struct nfs_fattr *fattr,
1077 				    rpc_authflavor_t flavor)
1078 {
1079 	struct nfs_server *server;
1080 	int error;
1081 
1082 	server = nfs_alloc_server();
1083 	if (!server)
1084 		return ERR_PTR(-ENOMEM);
1085 
1086 	server->cred = get_cred(source->cred);
1087 
1088 	/* Copy data from the source */
1089 	server->nfs_client = source->nfs_client;
1090 	server->destroy = source->destroy;
1091 	refcount_inc(&server->nfs_client->cl_count);
1092 	nfs_server_copy_userdata(server, source);
1093 
1094 	server->fsid = fattr->fsid;
1095 
1096 	error = nfs_init_server_rpcclient(server,
1097 			source->client->cl_timeout,
1098 			flavor);
1099 	if (error < 0)
1100 		goto out_free_server;
1101 
1102 	/* probe the filesystem info for this server filesystem */
1103 	error = nfs_probe_server(server, fh);
1104 	if (error < 0)
1105 		goto out_free_server;
1106 
1107 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1108 		server->namelen = NFS4_MAXNAMLEN;
1109 
1110 	error = nfs_start_lockd(server);
1111 	if (error < 0)
1112 		goto out_free_server;
1113 
1114 	nfs_server_insert_lists(server);
1115 	server->mount_time = jiffies;
1116 
1117 	return server;
1118 
1119 out_free_server:
1120 	nfs_free_server(server);
1121 	return ERR_PTR(error);
1122 }
1123 EXPORT_SYMBOL_GPL(nfs_clone_server);
1124 
1125 void nfs_clients_init(struct net *net)
1126 {
1127 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1128 
1129 	INIT_LIST_HEAD(&nn->nfs_client_list);
1130 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1131 #if IS_ENABLED(CONFIG_NFS_V4)
1132 	idr_init(&nn->cb_ident_idr);
1133 #endif
1134 	spin_lock_init(&nn->nfs_client_lock);
1135 	nn->boot_time = ktime_get_real();
1136 
1137 	nfs_netns_sysfs_setup(nn, net);
1138 }
1139 
1140 void nfs_clients_exit(struct net *net)
1141 {
1142 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1143 
1144 	nfs_netns_sysfs_destroy(nn);
1145 	nfs_cleanup_cb_ident_idr(net);
1146 	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));
1147 	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));
1148 }
1149 
1150 #ifdef CONFIG_PROC_FS
1151 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1152 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1153 static void nfs_server_list_stop(struct seq_file *p, void *v);
1154 static int nfs_server_list_show(struct seq_file *m, void *v);
1155 
1156 static const struct seq_operations nfs_server_list_ops = {
1157 	.start	= nfs_server_list_start,
1158 	.next	= nfs_server_list_next,
1159 	.stop	= nfs_server_list_stop,
1160 	.show	= nfs_server_list_show,
1161 };
1162 
1163 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1164 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1165 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1166 static int nfs_volume_list_show(struct seq_file *m, void *v);
1167 
1168 static const struct seq_operations nfs_volume_list_ops = {
1169 	.start	= nfs_volume_list_start,
1170 	.next	= nfs_volume_list_next,
1171 	.stop	= nfs_volume_list_stop,
1172 	.show	= nfs_volume_list_show,
1173 };
1174 
1175 /*
1176  * set up the iterator to start reading from the server list and return the first item
1177  */
1178 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1179 				__acquires(&nn->nfs_client_lock)
1180 {
1181 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1182 
1183 	/* lock the list against modification */
1184 	spin_lock(&nn->nfs_client_lock);
1185 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1186 }
1187 
1188 /*
1189  * move to next server
1190  */
1191 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1192 {
1193 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1194 
1195 	return seq_list_next(v, &nn->nfs_client_list, pos);
1196 }
1197 
1198 /*
1199  * clean up after reading from the transports list
1200  */
1201 static void nfs_server_list_stop(struct seq_file *p, void *v)
1202 				__releases(&nn->nfs_client_lock)
1203 {
1204 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1205 
1206 	spin_unlock(&nn->nfs_client_lock);
1207 }
1208 
1209 /*
1210  * display a header line followed by a load of call lines
1211  */
1212 static int nfs_server_list_show(struct seq_file *m, void *v)
1213 {
1214 	struct nfs_client *clp;
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_client_list) {
1219 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1220 		return 0;
1221 	}
1222 
1223 	/* display one transport per line on subsequent lines */
1224 	clp = list_entry(v, struct nfs_client, cl_share_link);
1225 
1226 	/* Check if the client is initialized */
1227 	if (clp->cl_cons_state != NFS_CS_READY)
1228 		return 0;
1229 
1230 	rcu_read_lock();
1231 	seq_printf(m, "v%u %s %s %3d %s\n",
1232 		   clp->rpc_ops->version,
1233 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1234 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1235 		   refcount_read(&clp->cl_count),
1236 		   clp->cl_hostname);
1237 	rcu_read_unlock();
1238 
1239 	return 0;
1240 }
1241 
1242 /*
1243  * set up the iterator to start reading from the volume list and return the first item
1244  */
1245 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1246 				__acquires(&nn->nfs_client_lock)
1247 {
1248 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1249 
1250 	/* lock the list against modification */
1251 	spin_lock(&nn->nfs_client_lock);
1252 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1253 }
1254 
1255 /*
1256  * move to next volume
1257  */
1258 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1259 {
1260 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1261 
1262 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1263 }
1264 
1265 /*
1266  * clean up after reading from the transports list
1267  */
1268 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1269 				__releases(&nn->nfs_client_lock)
1270 {
1271 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1272 
1273 	spin_unlock(&nn->nfs_client_lock);
1274 }
1275 
1276 /*
1277  * display a header line followed by a load of call lines
1278  */
1279 static int nfs_volume_list_show(struct seq_file *m, void *v)
1280 {
1281 	struct nfs_server *server;
1282 	struct nfs_client *clp;
1283 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1284 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1285 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1286 
1287 	/* display header on line 1 */
1288 	if (v == &nn->nfs_volume_list) {
1289 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1290 			    "                              FSC\n");
1291 		return 0;
1292 	}
1293 	/* display one transport per line on subsequent lines */
1294 	server = list_entry(v, struct nfs_server, master_link);
1295 	clp = server->nfs_client;
1296 
1297 	snprintf(dev, sizeof(dev), "%u:%u",
1298 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1299 
1300 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1301 		 (unsigned long long) server->fsid.major,
1302 		 (unsigned long long) server->fsid.minor);
1303 
1304 	rcu_read_lock();
1305 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1306 		   clp->rpc_ops->version,
1307 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1308 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1309 		   dev,
1310 		   fsid,
1311 		   nfs_server_fscache_state(server));
1312 	rcu_read_unlock();
1313 
1314 	return 0;
1315 }
1316 
1317 int nfs_fs_proc_net_init(struct net *net)
1318 {
1319 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1320 	struct proc_dir_entry *p;
1321 
1322 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1323 	if (!nn->proc_nfsfs)
1324 		goto error_0;
1325 
1326 	/* a file of servers with which we're dealing */
1327 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1328 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1329 	if (!p)
1330 		goto error_1;
1331 
1332 	/* a file of volumes that we have mounted */
1333 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1334 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1335 	if (!p)
1336 		goto error_1;
1337 	return 0;
1338 
1339 error_1:
1340 	remove_proc_subtree("nfsfs", net->proc_net);
1341 error_0:
1342 	return -ENOMEM;
1343 }
1344 
1345 void nfs_fs_proc_net_exit(struct net *net)
1346 {
1347 	remove_proc_subtree("nfsfs", net->proc_net);
1348 }
1349 
1350 /*
1351  * initialise the /proc/fs/nfsfs/ directory
1352  */
1353 int __init nfs_fs_proc_init(void)
1354 {
1355 	if (!proc_mkdir("fs/nfsfs", NULL))
1356 		goto error_0;
1357 
1358 	/* a file of servers with which we're dealing */
1359 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1360 		goto error_1;
1361 
1362 	/* a file of volumes that we have mounted */
1363 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1364 		goto error_1;
1365 
1366 	return 0;
1367 error_1:
1368 	remove_proc_subtree("fs/nfsfs", NULL);
1369 error_0:
1370 	return -ENOMEM;
1371 }
1372 
1373 /*
1374  * clean up the /proc/fs/nfsfs/ directory
1375  */
1376 void nfs_fs_proc_exit(void)
1377 {
1378 	remove_proc_subtree("fs/nfsfs", NULL);
1379 }
1380 
1381 #endif /* CONFIG_PROC_FS */
1382