xref: /linux/fs/nfs/client.c (revision 7cc9196675234d4de0e1e19b9da1a8b86ecfeedd)
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_flags = cl_init->init_flags;
181 	clp->cl_proto = cl_init->proto;
182 	clp->cl_nconnect = cl_init->nconnect;
183 	clp->cl_max_connect = cl_init->max_connect ? cl_init->max_connect : 1;
184 	clp->cl_net = get_net(cl_init->net);
185 
186 	clp->cl_principal = "*";
187 	clp->cl_xprtsec = cl_init->xprtsec;
188 	return clp;
189 
190 error_cleanup:
191 	put_nfs_version(clp->cl_nfs_mod);
192 error_dealloc:
193 	kfree(clp);
194 error_0:
195 	return ERR_PTR(err);
196 }
197 EXPORT_SYMBOL_GPL(nfs_alloc_client);
198 
199 #if IS_ENABLED(CONFIG_NFS_V4)
200 static void nfs_cleanup_cb_ident_idr(struct net *net)
201 {
202 	struct nfs_net *nn = net_generic(net, nfs_net_id);
203 
204 	idr_destroy(&nn->cb_ident_idr);
205 }
206 
207 /* nfs_client_lock held */
208 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
209 {
210 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
211 
212 	if (clp->cl_cb_ident)
213 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
214 }
215 
216 static void pnfs_init_server(struct nfs_server *server)
217 {
218 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
219 }
220 
221 #else
222 static void nfs_cleanup_cb_ident_idr(struct net *net)
223 {
224 }
225 
226 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
227 {
228 }
229 
230 static void pnfs_init_server(struct nfs_server *server)
231 {
232 }
233 
234 #endif /* CONFIG_NFS_V4 */
235 
236 /*
237  * Destroy a shared client record
238  */
239 void nfs_free_client(struct nfs_client *clp)
240 {
241 	/* -EIO all pending I/O */
242 	if (!IS_ERR(clp->cl_rpcclient))
243 		rpc_shutdown_client(clp->cl_rpcclient);
244 
245 	put_net(clp->cl_net);
246 	put_nfs_version(clp->cl_nfs_mod);
247 	kfree(clp->cl_hostname);
248 	kfree(clp->cl_acceptor);
249 	kfree_rcu(clp, rcu);
250 }
251 EXPORT_SYMBOL_GPL(nfs_free_client);
252 
253 /*
254  * Release a reference to a shared client record
255  */
256 void nfs_put_client(struct nfs_client *clp)
257 {
258 	struct nfs_net *nn;
259 
260 	if (!clp)
261 		return;
262 
263 	nn = net_generic(clp->cl_net, nfs_net_id);
264 
265 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
266 		list_del(&clp->cl_share_link);
267 		nfs_cb_idr_remove_locked(clp);
268 		spin_unlock(&nn->nfs_client_lock);
269 
270 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
271 
272 		clp->rpc_ops->free_client(clp);
273 	}
274 }
275 EXPORT_SYMBOL_GPL(nfs_put_client);
276 
277 /*
278  * Find an nfs_client on the list that matches the initialisation data
279  * that is supplied.
280  */
281 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
282 {
283 	struct nfs_client *clp;
284 	const struct sockaddr *sap = (struct sockaddr *)data->addr;
285 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
286 	int error;
287 
288 again:
289 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
290 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
291 		/* Don't match clients that failed to initialise properly */
292 		if (clp->cl_cons_state < 0)
293 			continue;
294 
295 		/* If a client is still initializing then we need to wait */
296 		if (clp->cl_cons_state > NFS_CS_READY) {
297 			refcount_inc(&clp->cl_count);
298 			spin_unlock(&nn->nfs_client_lock);
299 			error = nfs_wait_client_init_complete(clp);
300 			nfs_put_client(clp);
301 			spin_lock(&nn->nfs_client_lock);
302 			if (error < 0)
303 				return ERR_PTR(error);
304 			goto again;
305 		}
306 
307 		/* Different NFS versions cannot share the same nfs_client */
308 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
309 			continue;
310 
311 		if (clp->cl_proto != data->proto)
312 			continue;
313 		/* Match nfsv4 minorversion */
314 		if (clp->cl_minorversion != data->minorversion)
315 			continue;
316 
317 		/* Match request for a dedicated DS */
318 		if (test_bit(NFS_CS_DS, &data->init_flags) !=
319 		    test_bit(NFS_CS_DS, &clp->cl_flags))
320 			continue;
321 
322 		/* Match the full socket address */
323 		if (!rpc_cmp_addr_port(sap, clap))
324 			/* Match all xprt_switch full socket addresses */
325 			if (IS_ERR(clp->cl_rpcclient) ||
326                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
327 							   sap))
328 				continue;
329 
330 		/* Match the xprt security policy */
331 		if (clp->cl_xprtsec.policy != data->xprtsec.policy)
332 			continue;
333 
334 		refcount_inc(&clp->cl_count);
335 		return clp;
336 	}
337 	return NULL;
338 }
339 
340 /*
341  * Return true if @clp is done initializing, false if still working on it.
342  *
343  * Use nfs_client_init_status to check if it was successful.
344  */
345 bool nfs_client_init_is_complete(const struct nfs_client *clp)
346 {
347 	return clp->cl_cons_state <= NFS_CS_READY;
348 }
349 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
350 
351 /*
352  * Return 0 if @clp was successfully initialized, -errno otherwise.
353  *
354  * This must be called *after* nfs_client_init_is_complete() returns true,
355  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
356  */
357 int nfs_client_init_status(const struct nfs_client *clp)
358 {
359 	/* called without checking nfs_client_init_is_complete */
360 	if (clp->cl_cons_state > NFS_CS_READY) {
361 		WARN_ON_ONCE(1);
362 		return -EINVAL;
363 	}
364 	return clp->cl_cons_state;
365 }
366 EXPORT_SYMBOL_GPL(nfs_client_init_status);
367 
368 int nfs_wait_client_init_complete(const struct nfs_client *clp)
369 {
370 	return wait_event_killable(nfs_client_active_wq,
371 			nfs_client_init_is_complete(clp));
372 }
373 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
374 
375 /*
376  * Found an existing client.  Make sure it's ready before returning.
377  */
378 static struct nfs_client *
379 nfs_found_client(const struct nfs_client_initdata *cl_init,
380 		 struct nfs_client *clp)
381 {
382 	int error;
383 
384 	error = nfs_wait_client_init_complete(clp);
385 	if (error < 0) {
386 		nfs_put_client(clp);
387 		return ERR_PTR(-ERESTARTSYS);
388 	}
389 
390 	if (clp->cl_cons_state < NFS_CS_READY) {
391 		error = clp->cl_cons_state;
392 		nfs_put_client(clp);
393 		return ERR_PTR(error);
394 	}
395 
396 	smp_rmb();
397 	return clp;
398 }
399 
400 /*
401  * Look up a client by IP address and protocol version
402  * - creates a new record if one doesn't yet exist
403  */
404 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
405 {
406 	struct nfs_client *clp, *new = NULL;
407 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
408 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
409 
410 	if (cl_init->hostname == NULL) {
411 		WARN_ON(1);
412 		return ERR_PTR(-EINVAL);
413 	}
414 
415 	/* see if the client already exists */
416 	do {
417 		spin_lock(&nn->nfs_client_lock);
418 
419 		clp = nfs_match_client(cl_init);
420 		if (clp) {
421 			spin_unlock(&nn->nfs_client_lock);
422 			if (new)
423 				new->rpc_ops->free_client(new);
424 			if (IS_ERR(clp))
425 				return clp;
426 			return nfs_found_client(cl_init, clp);
427 		}
428 		if (new) {
429 			list_add_tail(&new->cl_share_link,
430 					&nn->nfs_client_list);
431 			spin_unlock(&nn->nfs_client_lock);
432 			return rpc_ops->init_client(new, cl_init);
433 		}
434 
435 		spin_unlock(&nn->nfs_client_lock);
436 
437 		new = rpc_ops->alloc_client(cl_init);
438 	} while (!IS_ERR(new));
439 
440 	return new;
441 }
442 EXPORT_SYMBOL_GPL(nfs_get_client);
443 
444 /*
445  * Mark a server as ready or failed
446  */
447 void nfs_mark_client_ready(struct nfs_client *clp, int state)
448 {
449 	smp_wmb();
450 	clp->cl_cons_state = state;
451 	wake_up_all(&nfs_client_active_wq);
452 }
453 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
454 
455 /*
456  * Initialise the timeout values for a connection
457  */
458 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
459 				    int timeo, int retrans)
460 {
461 	to->to_initval = timeo * HZ / 10;
462 	to->to_retries = retrans;
463 
464 	switch (proto) {
465 	case XPRT_TRANSPORT_TCP:
466 	case XPRT_TRANSPORT_TCP_TLS:
467 	case XPRT_TRANSPORT_RDMA:
468 		if (retrans == NFS_UNSPEC_RETRANS)
469 			to->to_retries = NFS_DEF_TCP_RETRANS;
470 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
471 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
472 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
473 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
474 		to->to_increment = to->to_initval;
475 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
476 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
477 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
478 		if (to->to_maxval < to->to_initval)
479 			to->to_maxval = to->to_initval;
480 		to->to_exponential = 0;
481 		break;
482 	case XPRT_TRANSPORT_UDP:
483 		if (retrans == NFS_UNSPEC_RETRANS)
484 			to->to_retries = NFS_DEF_UDP_RETRANS;
485 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
486 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
487 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
488 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
489 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
490 		to->to_exponential = 1;
491 		break;
492 	default:
493 		BUG();
494 	}
495 }
496 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
497 
498 /*
499  * Create an RPC client handle
500  */
501 int nfs_create_rpc_client(struct nfs_client *clp,
502 			  const struct nfs_client_initdata *cl_init,
503 			  rpc_authflavor_t flavor)
504 {
505 	struct rpc_clnt		*clnt = NULL;
506 	struct rpc_create_args args = {
507 		.net		= clp->cl_net,
508 		.protocol	= clp->cl_proto,
509 		.nconnect	= clp->cl_nconnect,
510 		.address	= (struct sockaddr *)&clp->cl_addr,
511 		.addrsize	= clp->cl_addrlen,
512 		.timeout	= cl_init->timeparms,
513 		.servername	= clp->cl_hostname,
514 		.nodename	= cl_init->nodename,
515 		.program	= &nfs_program,
516 		.version	= clp->rpc_ops->version,
517 		.authflavor	= flavor,
518 		.cred		= cl_init->cred,
519 		.xprtsec	= cl_init->xprtsec,
520 		.connect_timeout = cl_init->connect_timeout,
521 		.reconnect_timeout = cl_init->reconnect_timeout,
522 	};
523 
524 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
525 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
526 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
527 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
528 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
529 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
530 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
531 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
532 	if (test_bit(NFS_CS_NOPING, &clp->cl_flags))
533 		args.flags |= RPC_CLNT_CREATE_NOPING;
534 	if (test_bit(NFS_CS_REUSEPORT, &clp->cl_flags))
535 		args.flags |= RPC_CLNT_CREATE_REUSEPORT;
536 
537 	if (!IS_ERR(clp->cl_rpcclient))
538 		return 0;
539 
540 	clnt = rpc_create(&args);
541 	if (IS_ERR(clnt)) {
542 		dprintk("%s: cannot create RPC client. Error = %ld\n",
543 				__func__, PTR_ERR(clnt));
544 		return PTR_ERR(clnt);
545 	}
546 
547 	clnt->cl_principal = clp->cl_principal;
548 	clp->cl_rpcclient = clnt;
549 	clnt->cl_max_connect = clp->cl_max_connect;
550 	return 0;
551 }
552 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
553 
554 /*
555  * Version 2 or 3 client destruction
556  */
557 static void nfs_destroy_server(struct nfs_server *server)
558 {
559 	if (server->nlm_host)
560 		nlmclnt_done(server->nlm_host);
561 }
562 
563 /*
564  * Version 2 or 3 lockd setup
565  */
566 static int nfs_start_lockd(struct nfs_server *server)
567 {
568 	struct nlm_host *host;
569 	struct nfs_client *clp = server->nfs_client;
570 	struct nlmclnt_initdata nlm_init = {
571 		.hostname	= clp->cl_hostname,
572 		.address	= (struct sockaddr *)&clp->cl_addr,
573 		.addrlen	= clp->cl_addrlen,
574 		.nfs_version	= clp->rpc_ops->version,
575 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
576 					1 : 0,
577 		.net		= clp->cl_net,
578 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
579 		.cred		= server->cred,
580 	};
581 
582 	if (nlm_init.nfs_version > 3)
583 		return 0;
584 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
585 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
586 		return 0;
587 
588 	switch (clp->cl_proto) {
589 		default:
590 			nlm_init.protocol = IPPROTO_TCP;
591 			break;
592 #ifndef CONFIG_NFS_DISABLE_UDP_SUPPORT
593 		case XPRT_TRANSPORT_UDP:
594 			nlm_init.protocol = IPPROTO_UDP;
595 #endif
596 	}
597 
598 	host = nlmclnt_init(&nlm_init);
599 	if (IS_ERR(host))
600 		return PTR_ERR(host);
601 
602 	server->nlm_host = host;
603 	server->destroy = nfs_destroy_server;
604 	nfs_sysfs_link_rpc_client(server, nlmclnt_rpc_clnt(host), NULL);
605 	return 0;
606 }
607 
608 /*
609  * Create a general RPC client
610  */
611 int nfs_init_server_rpcclient(struct nfs_server *server,
612 		const struct rpc_timeout *timeo,
613 		rpc_authflavor_t pseudoflavour)
614 {
615 	struct nfs_client *clp = server->nfs_client;
616 
617 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
618 							pseudoflavour);
619 	if (IS_ERR(server->client)) {
620 		dprintk("%s: couldn't create rpc_client!\n", __func__);
621 		return PTR_ERR(server->client);
622 	}
623 
624 	memcpy(&server->client->cl_timeout_default,
625 			timeo,
626 			sizeof(server->client->cl_timeout_default));
627 	server->client->cl_timeout = &server->client->cl_timeout_default;
628 	server->client->cl_softrtry = 0;
629 	if (server->flags & NFS_MOUNT_SOFTERR)
630 		server->client->cl_softerr = 1;
631 	if (server->flags & NFS_MOUNT_SOFT)
632 		server->client->cl_softrtry = 1;
633 
634 	nfs_sysfs_link_rpc_client(server, server->client, NULL);
635 	return 0;
636 }
637 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
638 
639 /**
640  * nfs_init_client - Initialise an NFS2 or NFS3 client
641  *
642  * @clp: nfs_client to initialise
643  * @cl_init: Initialisation parameters
644  *
645  * Returns pointer to an NFS client, or an ERR_PTR value.
646  */
647 struct nfs_client *nfs_init_client(struct nfs_client *clp,
648 				   const struct nfs_client_initdata *cl_init)
649 {
650 	int error;
651 
652 	/* the client is already initialised */
653 	if (clp->cl_cons_state == NFS_CS_READY)
654 		return clp;
655 
656 	/*
657 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
658 	 * - RFC 2623, sec 2.3.2
659 	 */
660 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
661 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
662 	if (error < 0) {
663 		nfs_put_client(clp);
664 		clp = ERR_PTR(error);
665 	}
666 	return clp;
667 }
668 EXPORT_SYMBOL_GPL(nfs_init_client);
669 
670 /*
671  * Create a version 2 or 3 client
672  */
673 static int nfs_init_server(struct nfs_server *server,
674 			   const struct fs_context *fc)
675 {
676 	const struct nfs_fs_context *ctx = nfs_fc2context(fc);
677 	struct rpc_timeout timeparms;
678 	struct nfs_client_initdata cl_init = {
679 		.hostname = ctx->nfs_server.hostname,
680 		.addr = &ctx->nfs_server._address,
681 		.addrlen = ctx->nfs_server.addrlen,
682 		.nfs_mod = ctx->nfs_mod,
683 		.proto = ctx->nfs_server.protocol,
684 		.net = fc->net_ns,
685 		.timeparms = &timeparms,
686 		.cred = server->cred,
687 		.nconnect = ctx->nfs_server.nconnect,
688 		.init_flags = (1UL << NFS_CS_REUSEPORT),
689 		.xprtsec = ctx->xprtsec,
690 	};
691 	struct nfs_client *clp;
692 	int error;
693 
694 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
695 				ctx->timeo, ctx->retrans);
696 	if (ctx->flags & NFS_MOUNT_NORESVPORT)
697 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
698 
699 	/* Allocate or find a client reference we can use */
700 	clp = nfs_get_client(&cl_init);
701 	if (IS_ERR(clp))
702 		return PTR_ERR(clp);
703 
704 	server->nfs_client = clp;
705 	nfs_sysfs_add_server(server);
706 	nfs_sysfs_link_rpc_client(server, clp->cl_rpcclient, "_state");
707 
708 	/* Initialise the client representation from the mount data */
709 	server->flags = ctx->flags;
710 	server->options = ctx->options;
711 	server->caps |= NFS_CAP_HARDLINKS | NFS_CAP_SYMLINKS;
712 
713 	switch (clp->rpc_ops->version) {
714 	case 2:
715 		server->fattr_valid = NFS_ATTR_FATTR_V2;
716 		break;
717 	case 3:
718 		server->fattr_valid = NFS_ATTR_FATTR_V3;
719 		break;
720 	default:
721 		server->fattr_valid = NFS_ATTR_FATTR_V4;
722 	}
723 
724 	if (ctx->rsize)
725 		server->rsize = nfs_io_size(ctx->rsize, clp->cl_proto);
726 	if (ctx->wsize)
727 		server->wsize = nfs_io_size(ctx->wsize, clp->cl_proto);
728 
729 	server->acregmin = ctx->acregmin * HZ;
730 	server->acregmax = ctx->acregmax * HZ;
731 	server->acdirmin = ctx->acdirmin * HZ;
732 	server->acdirmax = ctx->acdirmax * HZ;
733 
734 	/* Start lockd here, before we might error out */
735 	error = nfs_start_lockd(server);
736 	if (error < 0)
737 		goto error;
738 
739 	server->port = ctx->nfs_server.port;
740 	server->auth_info = ctx->auth_info;
741 
742 	error = nfs_init_server_rpcclient(server, &timeparms,
743 					  ctx->selected_flavor);
744 	if (error < 0)
745 		goto error;
746 
747 	/* Preserve the values of mount_server-related mount options */
748 	if (ctx->mount_server.addrlen) {
749 		memcpy(&server->mountd_address, &ctx->mount_server.address,
750 			ctx->mount_server.addrlen);
751 		server->mountd_addrlen = ctx->mount_server.addrlen;
752 	}
753 	server->mountd_version = ctx->mount_server.version;
754 	server->mountd_port = ctx->mount_server.port;
755 	server->mountd_protocol = ctx->mount_server.protocol;
756 
757 	server->namelen  = ctx->namlen;
758 	return 0;
759 
760 error:
761 	server->nfs_client = NULL;
762 	nfs_put_client(clp);
763 	return error;
764 }
765 
766 /*
767  * Load up the server record from information gained in an fsinfo record
768  */
769 static void nfs_server_set_fsinfo(struct nfs_server *server,
770 				  struct nfs_fsinfo *fsinfo)
771 {
772 	struct nfs_client *clp = server->nfs_client;
773 	unsigned long max_rpc_payload, raw_max_rpc_payload;
774 
775 	/* Work out a lot of parameters */
776 	if (server->rsize == 0)
777 		server->rsize = nfs_io_size(fsinfo->rtpref, clp->cl_proto);
778 	if (server->wsize == 0)
779 		server->wsize = nfs_io_size(fsinfo->wtpref, clp->cl_proto);
780 
781 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
782 		server->rsize = nfs_io_size(fsinfo->rtmax, clp->cl_proto);
783 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
784 		server->wsize = nfs_io_size(fsinfo->wtmax, clp->cl_proto);
785 
786 	raw_max_rpc_payload = rpc_max_payload(server->client);
787 	max_rpc_payload = nfs_block_size(raw_max_rpc_payload, NULL);
788 
789 	if (server->rsize > max_rpc_payload)
790 		server->rsize = max_rpc_payload;
791 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
792 		server->rsize = NFS_MAX_FILE_IO_SIZE;
793 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
794 
795 	if (server->wsize > max_rpc_payload)
796 		server->wsize = max_rpc_payload;
797 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
798 		server->wsize = NFS_MAX_FILE_IO_SIZE;
799 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
800 
801 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
802 
803 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
804 	if (server->dtsize > NFS_MAX_FILE_IO_SIZE)
805 		server->dtsize = NFS_MAX_FILE_IO_SIZE;
806 	if (server->dtsize > server->rsize)
807 		server->dtsize = server->rsize;
808 
809 	if (server->flags & NFS_MOUNT_NOAC) {
810 		server->acregmin = server->acregmax = 0;
811 		server->acdirmin = server->acdirmax = 0;
812 	}
813 
814 	server->maxfilesize = fsinfo->maxfilesize;
815 
816 	server->time_delta = fsinfo->time_delta;
817 	server->change_attr_type = fsinfo->change_attr_type;
818 
819 	server->clone_blksize = fsinfo->clone_blksize;
820 	/* We're airborne Set socket buffersize */
821 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
822 
823 #ifdef CONFIG_NFS_V4_2
824 	/*
825 	 * Defaults until limited by the session parameters.
826 	 */
827 	server->gxasize = min_t(unsigned int, raw_max_rpc_payload,
828 				XATTR_SIZE_MAX);
829 	server->sxasize = min_t(unsigned int, raw_max_rpc_payload,
830 				XATTR_SIZE_MAX);
831 	server->lxasize = min_t(unsigned int, raw_max_rpc_payload,
832 				nfs42_listxattr_xdrsize(XATTR_LIST_MAX));
833 
834 	if (fsinfo->xattr_support)
835 		server->caps |= NFS_CAP_XATTR;
836 #endif
837 }
838 
839 /*
840  * Probe filesystem information, including the FSID on v2/v3
841  */
842 static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
843 {
844 	struct nfs_fsinfo fsinfo;
845 	struct nfs_client *clp = server->nfs_client;
846 	int error;
847 
848 	if (clp->rpc_ops->set_capabilities != NULL) {
849 		error = clp->rpc_ops->set_capabilities(server, mntfh);
850 		if (error < 0)
851 			return error;
852 	}
853 
854 	fsinfo.fattr = fattr;
855 	fsinfo.nlayouttypes = 0;
856 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
857 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
858 	if (error < 0)
859 		return error;
860 
861 	nfs_server_set_fsinfo(server, &fsinfo);
862 
863 	/* Get some general file system info */
864 	if (server->namelen == 0) {
865 		struct nfs_pathconf pathinfo;
866 
867 		pathinfo.fattr = fattr;
868 		nfs_fattr_init(fattr);
869 
870 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
871 			server->namelen = pathinfo.max_namelen;
872 	}
873 
874 	if (clp->rpc_ops->discover_trunking != NULL &&
875 			(server->caps & NFS_CAP_FS_LOCATIONS &&
876 			 (server->flags & NFS_MOUNT_TRUNK_DISCOVERY))) {
877 		error = clp->rpc_ops->discover_trunking(server, mntfh);
878 		if (error < 0)
879 			return error;
880 	}
881 
882 	return 0;
883 }
884 
885 /*
886  * Grab the destination's particulars, including lease expiry time.
887  *
888  * Returns zero if probe succeeded and retrieved FSID matches the FSID
889  * we have cached.
890  */
891 int nfs_probe_server(struct nfs_server *server, struct nfs_fh *mntfh)
892 {
893 	struct nfs_fattr *fattr;
894 	int error;
895 
896 	fattr = nfs_alloc_fattr();
897 	if (fattr == NULL)
898 		return -ENOMEM;
899 
900 	/* Sanity: the probe won't work if the destination server
901 	 * does not recognize the migrated FH. */
902 	error = nfs_probe_fsinfo(server, mntfh, fattr);
903 
904 	nfs_free_fattr(fattr);
905 	return error;
906 }
907 EXPORT_SYMBOL_GPL(nfs_probe_server);
908 
909 /*
910  * Copy useful information when duplicating a server record
911  */
912 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
913 {
914 	target->flags = source->flags;
915 	target->rsize = source->rsize;
916 	target->wsize = source->wsize;
917 	target->acregmin = source->acregmin;
918 	target->acregmax = source->acregmax;
919 	target->acdirmin = source->acdirmin;
920 	target->acdirmax = source->acdirmax;
921 	target->caps = source->caps;
922 	target->options = source->options;
923 	target->auth_info = source->auth_info;
924 	target->port = source->port;
925 }
926 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
927 
928 void nfs_server_insert_lists(struct nfs_server *server)
929 {
930 	struct nfs_client *clp = server->nfs_client;
931 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
932 
933 	spin_lock(&nn->nfs_client_lock);
934 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
935 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
936 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
937 	spin_unlock(&nn->nfs_client_lock);
938 
939 }
940 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
941 
942 void nfs_server_remove_lists(struct nfs_server *server)
943 {
944 	struct nfs_client *clp = server->nfs_client;
945 	struct nfs_net *nn;
946 
947 	if (clp == NULL)
948 		return;
949 	nn = net_generic(clp->cl_net, nfs_net_id);
950 	spin_lock(&nn->nfs_client_lock);
951 	list_del_rcu(&server->client_link);
952 	if (list_empty(&clp->cl_superblocks))
953 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
954 	list_del(&server->master_link);
955 	spin_unlock(&nn->nfs_client_lock);
956 
957 	synchronize_rcu();
958 }
959 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
960 
961 static DEFINE_IDA(s_sysfs_ids);
962 
963 /*
964  * Allocate and initialise a server record
965  */
966 struct nfs_server *nfs_alloc_server(void)
967 {
968 	struct nfs_server *server;
969 
970 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
971 	if (!server)
972 		return NULL;
973 
974 	server->s_sysfs_id = ida_alloc(&s_sysfs_ids, GFP_KERNEL);
975 	if (server->s_sysfs_id < 0) {
976 		kfree(server);
977 		return NULL;
978 	}
979 
980 	server->client = server->client_acl = ERR_PTR(-EINVAL);
981 
982 	/* Zero out the NFS state stuff */
983 	INIT_LIST_HEAD(&server->client_link);
984 	INIT_LIST_HEAD(&server->master_link);
985 	INIT_LIST_HEAD(&server->delegations);
986 	INIT_LIST_HEAD(&server->layouts);
987 	INIT_LIST_HEAD(&server->state_owners_lru);
988 	INIT_LIST_HEAD(&server->ss_copies);
989 
990 	atomic_set(&server->active, 0);
991 
992 	server->io_stats = nfs_alloc_iostats();
993 	if (!server->io_stats) {
994 		kfree(server);
995 		return NULL;
996 	}
997 
998 	server->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
999 
1000 	ida_init(&server->openowner_id);
1001 	ida_init(&server->lockowner_id);
1002 	pnfs_init_server(server);
1003 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
1004 
1005 	return server;
1006 }
1007 EXPORT_SYMBOL_GPL(nfs_alloc_server);
1008 
1009 static void delayed_free(struct rcu_head *p)
1010 {
1011 	struct nfs_server *server = container_of(p, struct nfs_server, rcu);
1012 
1013 	nfs_free_iostats(server->io_stats);
1014 	kfree(server);
1015 }
1016 
1017 /*
1018  * Free up a server record
1019  */
1020 void nfs_free_server(struct nfs_server *server)
1021 {
1022 	nfs_server_remove_lists(server);
1023 
1024 	if (server->destroy != NULL)
1025 		server->destroy(server);
1026 
1027 	if (!IS_ERR(server->client_acl))
1028 		rpc_shutdown_client(server->client_acl);
1029 	if (!IS_ERR(server->client))
1030 		rpc_shutdown_client(server->client);
1031 
1032 	nfs_put_client(server->nfs_client);
1033 
1034 	if (server->kobj.state_initialized) {
1035 		nfs_sysfs_remove_server(server);
1036 		kobject_put(&server->kobj);
1037 	}
1038 	ida_free(&s_sysfs_ids, server->s_sysfs_id);
1039 
1040 	ida_destroy(&server->lockowner_id);
1041 	ida_destroy(&server->openowner_id);
1042 	put_cred(server->cred);
1043 	nfs_release_automount_timer();
1044 	call_rcu(&server->rcu, delayed_free);
1045 }
1046 EXPORT_SYMBOL_GPL(nfs_free_server);
1047 
1048 /*
1049  * Create a version 2 or 3 volume record
1050  * - keyed on server and FSID
1051  */
1052 struct nfs_server *nfs_create_server(struct fs_context *fc)
1053 {
1054 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1055 	struct nfs_server *server;
1056 	struct nfs_fattr *fattr;
1057 	int error;
1058 
1059 	server = nfs_alloc_server();
1060 	if (!server)
1061 		return ERR_PTR(-ENOMEM);
1062 
1063 	server->cred = get_cred(fc->cred);
1064 
1065 	error = -ENOMEM;
1066 	fattr = nfs_alloc_fattr();
1067 	if (fattr == NULL)
1068 		goto error;
1069 
1070 	/* Get a client representation */
1071 	error = nfs_init_server(server, fc);
1072 	if (error < 0)
1073 		goto error;
1074 
1075 	/* Probe the root fh to retrieve its FSID */
1076 	error = nfs_probe_fsinfo(server, ctx->mntfh, fattr);
1077 	if (error < 0)
1078 		goto error;
1079 	if (server->nfs_client->rpc_ops->version == 3) {
1080 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
1081 			server->namelen = NFS3_MAXNAMLEN;
1082 		if (!(ctx->flags & NFS_MOUNT_NORDIRPLUS))
1083 			server->caps |= NFS_CAP_READDIRPLUS;
1084 	} else {
1085 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
1086 			server->namelen = NFS2_MAXNAMLEN;
1087 	}
1088 
1089 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
1090 		error = ctx->nfs_mod->rpc_ops->getattr(server, ctx->mntfh,
1091 						       fattr, NULL);
1092 		if (error < 0) {
1093 			dprintk("nfs_create_server: getattr error = %d\n", -error);
1094 			goto error;
1095 		}
1096 	}
1097 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
1098 
1099 	dprintk("Server FSID: %llx:%llx\n",
1100 		(unsigned long long) server->fsid.major,
1101 		(unsigned long long) server->fsid.minor);
1102 
1103 	nfs_server_insert_lists(server);
1104 	server->mount_time = jiffies;
1105 	nfs_free_fattr(fattr);
1106 	return server;
1107 
1108 error:
1109 	nfs_free_fattr(fattr);
1110 	nfs_free_server(server);
1111 	return ERR_PTR(error);
1112 }
1113 EXPORT_SYMBOL_GPL(nfs_create_server);
1114 
1115 /*
1116  * Clone an NFS2, NFS3 or NFS4 server record
1117  */
1118 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1119 				    struct nfs_fh *fh,
1120 				    struct nfs_fattr *fattr,
1121 				    rpc_authflavor_t flavor)
1122 {
1123 	struct nfs_server *server;
1124 	int error;
1125 
1126 	server = nfs_alloc_server();
1127 	if (!server)
1128 		return ERR_PTR(-ENOMEM);
1129 
1130 	server->cred = get_cred(source->cred);
1131 
1132 	/* Copy data from the source */
1133 	server->nfs_client = source->nfs_client;
1134 	server->destroy = source->destroy;
1135 	refcount_inc(&server->nfs_client->cl_count);
1136 	nfs_server_copy_userdata(server, source);
1137 
1138 	server->fsid = fattr->fsid;
1139 
1140 	nfs_sysfs_add_server(server);
1141 
1142 	nfs_sysfs_link_rpc_client(server,
1143 		server->nfs_client->cl_rpcclient, "_state");
1144 
1145 	error = nfs_init_server_rpcclient(server,
1146 			source->client->cl_timeout,
1147 			flavor);
1148 	if (error < 0)
1149 		goto out_free_server;
1150 
1151 	/* probe the filesystem info for this server filesystem */
1152 	error = nfs_probe_server(server, fh);
1153 	if (error < 0)
1154 		goto out_free_server;
1155 
1156 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1157 		server->namelen = NFS4_MAXNAMLEN;
1158 
1159 	error = nfs_start_lockd(server);
1160 	if (error < 0)
1161 		goto out_free_server;
1162 
1163 	nfs_server_insert_lists(server);
1164 	server->mount_time = jiffies;
1165 
1166 	return server;
1167 
1168 out_free_server:
1169 	nfs_free_server(server);
1170 	return ERR_PTR(error);
1171 }
1172 EXPORT_SYMBOL_GPL(nfs_clone_server);
1173 
1174 void nfs_clients_init(struct net *net)
1175 {
1176 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1177 
1178 	INIT_LIST_HEAD(&nn->nfs_client_list);
1179 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1180 #if IS_ENABLED(CONFIG_NFS_V4)
1181 	idr_init(&nn->cb_ident_idr);
1182 #endif
1183 	spin_lock_init(&nn->nfs_client_lock);
1184 	nn->boot_time = ktime_get_real();
1185 
1186 	nfs_netns_sysfs_setup(nn, net);
1187 }
1188 
1189 void nfs_clients_exit(struct net *net)
1190 {
1191 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1192 
1193 	nfs_netns_sysfs_destroy(nn);
1194 	nfs_cleanup_cb_ident_idr(net);
1195 	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));
1196 	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));
1197 }
1198 
1199 #ifdef CONFIG_PROC_FS
1200 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1201 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1202 static void nfs_server_list_stop(struct seq_file *p, void *v);
1203 static int nfs_server_list_show(struct seq_file *m, void *v);
1204 
1205 static const struct seq_operations nfs_server_list_ops = {
1206 	.start	= nfs_server_list_start,
1207 	.next	= nfs_server_list_next,
1208 	.stop	= nfs_server_list_stop,
1209 	.show	= nfs_server_list_show,
1210 };
1211 
1212 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1213 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1214 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1215 static int nfs_volume_list_show(struct seq_file *m, void *v);
1216 
1217 static const struct seq_operations nfs_volume_list_ops = {
1218 	.start	= nfs_volume_list_start,
1219 	.next	= nfs_volume_list_next,
1220 	.stop	= nfs_volume_list_stop,
1221 	.show	= nfs_volume_list_show,
1222 };
1223 
1224 /*
1225  * set up the iterator to start reading from the server list and return the first item
1226  */
1227 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1228 				__acquires(&nn->nfs_client_lock)
1229 {
1230 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1231 
1232 	/* lock the list against modification */
1233 	spin_lock(&nn->nfs_client_lock);
1234 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1235 }
1236 
1237 /*
1238  * move to next server
1239  */
1240 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1241 {
1242 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1243 
1244 	return seq_list_next(v, &nn->nfs_client_list, pos);
1245 }
1246 
1247 /*
1248  * clean up after reading from the transports list
1249  */
1250 static void nfs_server_list_stop(struct seq_file *p, void *v)
1251 				__releases(&nn->nfs_client_lock)
1252 {
1253 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1254 
1255 	spin_unlock(&nn->nfs_client_lock);
1256 }
1257 
1258 /*
1259  * display a header line followed by a load of call lines
1260  */
1261 static int nfs_server_list_show(struct seq_file *m, void *v)
1262 {
1263 	struct nfs_client *clp;
1264 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1265 
1266 	/* display header on line 1 */
1267 	if (v == &nn->nfs_client_list) {
1268 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1269 		return 0;
1270 	}
1271 
1272 	/* display one transport per line on subsequent lines */
1273 	clp = list_entry(v, struct nfs_client, cl_share_link);
1274 
1275 	/* Check if the client is initialized */
1276 	if (clp->cl_cons_state != NFS_CS_READY)
1277 		return 0;
1278 
1279 	rcu_read_lock();
1280 	seq_printf(m, "v%u %s %s %3d %s\n",
1281 		   clp->rpc_ops->version,
1282 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1283 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1284 		   refcount_read(&clp->cl_count),
1285 		   clp->cl_hostname);
1286 	rcu_read_unlock();
1287 
1288 	return 0;
1289 }
1290 
1291 /*
1292  * set up the iterator to start reading from the volume list and return the first item
1293  */
1294 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1295 				__acquires(&nn->nfs_client_lock)
1296 {
1297 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1298 
1299 	/* lock the list against modification */
1300 	spin_lock(&nn->nfs_client_lock);
1301 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1302 }
1303 
1304 /*
1305  * move to next volume
1306  */
1307 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1308 {
1309 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1310 
1311 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1312 }
1313 
1314 /*
1315  * clean up after reading from the transports list
1316  */
1317 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1318 				__releases(&nn->nfs_client_lock)
1319 {
1320 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1321 
1322 	spin_unlock(&nn->nfs_client_lock);
1323 }
1324 
1325 /*
1326  * display a header line followed by a load of call lines
1327  */
1328 static int nfs_volume_list_show(struct seq_file *m, void *v)
1329 {
1330 	struct nfs_server *server;
1331 	struct nfs_client *clp;
1332 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1333 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1334 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1335 
1336 	/* display header on line 1 */
1337 	if (v == &nn->nfs_volume_list) {
1338 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1339 			    "                              FSC\n");
1340 		return 0;
1341 	}
1342 	/* display one transport per line on subsequent lines */
1343 	server = list_entry(v, struct nfs_server, master_link);
1344 	clp = server->nfs_client;
1345 
1346 	snprintf(dev, sizeof(dev), "%u:%u",
1347 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1348 
1349 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1350 		 (unsigned long long) server->fsid.major,
1351 		 (unsigned long long) server->fsid.minor);
1352 
1353 	rcu_read_lock();
1354 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1355 		   clp->rpc_ops->version,
1356 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1357 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1358 		   dev,
1359 		   fsid,
1360 		   nfs_server_fscache_state(server));
1361 	rcu_read_unlock();
1362 
1363 	return 0;
1364 }
1365 
1366 int nfs_fs_proc_net_init(struct net *net)
1367 {
1368 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1369 	struct proc_dir_entry *p;
1370 
1371 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1372 	if (!nn->proc_nfsfs)
1373 		goto error_0;
1374 
1375 	/* a file of servers with which we're dealing */
1376 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1377 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1378 	if (!p)
1379 		goto error_1;
1380 
1381 	/* a file of volumes that we have mounted */
1382 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1383 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1384 	if (!p)
1385 		goto error_1;
1386 	return 0;
1387 
1388 error_1:
1389 	remove_proc_subtree("nfsfs", net->proc_net);
1390 error_0:
1391 	return -ENOMEM;
1392 }
1393 
1394 void nfs_fs_proc_net_exit(struct net *net)
1395 {
1396 	remove_proc_subtree("nfsfs", net->proc_net);
1397 }
1398 
1399 /*
1400  * initialise the /proc/fs/nfsfs/ directory
1401  */
1402 int __init nfs_fs_proc_init(void)
1403 {
1404 	if (!proc_mkdir("fs/nfsfs", NULL))
1405 		goto error_0;
1406 
1407 	/* a file of servers with which we're dealing */
1408 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1409 		goto error_1;
1410 
1411 	/* a file of volumes that we have mounted */
1412 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1413 		goto error_1;
1414 
1415 	return 0;
1416 error_1:
1417 	remove_proc_subtree("fs/nfsfs", NULL);
1418 error_0:
1419 	return -ENOMEM;
1420 }
1421 
1422 /*
1423  * clean up the /proc/fs/nfsfs/ directory
1424  */
1425 void nfs_fs_proc_exit(void)
1426 {
1427 	remove_proc_subtree("fs/nfsfs", NULL);
1428 	ida_destroy(&s_sysfs_ids);
1429 }
1430 
1431 #endif /* CONFIG_PROC_FS */
1432