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 #include <linux/nfslocalio.h>
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_RWLOCK(nfs_version_lock);
59 
60 static struct nfs_subversion *nfs_version_mods[5] = {
61 	[2] = NULL,
62 	[3] = NULL,
63 	[4] = NULL,
64 };
65 
66 /*
67  * RPC cruft for NFS
68  */
69 static const struct rpc_version *nfs_version[5] = {
70 	[2] = NULL,
71 	[3] = NULL,
72 	[4] = NULL,
73 };
74 
75 const struct rpc_program nfs_program = {
76 	.name			= "nfs",
77 	.number			= NFS_PROGRAM,
78 	.nrvers			= ARRAY_SIZE(nfs_version),
79 	.version		= nfs_version,
80 	.pipe_dir_name		= NFS_PIPE_DIRNAME,
81 };
82 
83 static struct nfs_subversion *__find_nfs_version(unsigned int version)
84 {
85 	struct nfs_subversion *nfs;
86 
87 	read_lock(&nfs_version_lock);
88 	nfs = nfs_version_mods[version];
89 	read_unlock(&nfs_version_lock);
90 	return nfs;
91 }
92 
93 struct nfs_subversion *find_nfs_version(unsigned int version)
94 {
95 	struct nfs_subversion *nfs = __find_nfs_version(version);
96 
97 	if (!nfs && request_module("nfsv%d", version) == 0)
98 		nfs = __find_nfs_version(version);
99 
100 	if (!nfs)
101 		return ERR_PTR(-EPROTONOSUPPORT);
102 
103 	if (!get_nfs_version(nfs))
104 		return ERR_PTR(-EAGAIN);
105 
106 	return nfs;
107 }
108 
109 int get_nfs_version(struct nfs_subversion *nfs)
110 {
111 	return try_module_get(nfs->owner);
112 }
113 EXPORT_SYMBOL_GPL(get_nfs_version);
114 
115 void put_nfs_version(struct nfs_subversion *nfs)
116 {
117 	module_put(nfs->owner);
118 }
119 
120 void register_nfs_version(struct nfs_subversion *nfs)
121 {
122 	write_lock(&nfs_version_lock);
123 
124 	nfs_version_mods[nfs->rpc_ops->version] = nfs;
125 	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
126 
127 	write_unlock(&nfs_version_lock);
128 }
129 EXPORT_SYMBOL_GPL(register_nfs_version);
130 
131 void unregister_nfs_version(struct nfs_subversion *nfs)
132 {
133 	write_lock(&nfs_version_lock);
134 
135 	nfs_version[nfs->rpc_ops->version] = NULL;
136 	nfs_version_mods[nfs->rpc_ops->version] = NULL;
137 
138 	write_unlock(&nfs_version_lock);
139 }
140 EXPORT_SYMBOL_GPL(unregister_nfs_version);
141 
142 /*
143  * Allocate a shared client record
144  *
145  * Since these are allocated/deallocated very rarely, we don't
146  * bother putting them in a slab cache...
147  */
148 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
149 {
150 	struct nfs_client *clp;
151 	int err = -ENOMEM;
152 
153 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
154 		goto error_0;
155 
156 	clp->cl_minorversion = cl_init->minorversion;
157 	clp->cl_nfs_mod = cl_init->nfs_mod;
158 	if (!get_nfs_version(clp->cl_nfs_mod))
159 		goto error_dealloc;
160 
161 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
162 
163 	refcount_set(&clp->cl_count, 1);
164 	clp->cl_cons_state = NFS_CS_INITING;
165 
166 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
167 	clp->cl_addrlen = cl_init->addrlen;
168 
169 	if (cl_init->hostname) {
170 		err = -ENOMEM;
171 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
172 		if (!clp->cl_hostname)
173 			goto error_cleanup;
174 	}
175 
176 	INIT_LIST_HEAD(&clp->cl_superblocks);
177 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
178 
179 	clp->cl_flags = cl_init->init_flags;
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_track(cl_init->net, &clp->cl_ns_tracker, GFP_KERNEL);
184 
185 #if IS_ENABLED(CONFIG_NFS_LOCALIO)
186 	seqlock_init(&clp->cl_boot_lock);
187 	ktime_get_real_ts64(&clp->cl_nfssvc_boot);
188 	nfs_uuid_init(&clp->cl_uuid);
189 	INIT_WORK(&clp->cl_local_probe_work, nfs_local_probe_async_work);
190 #endif /* CONFIG_NFS_LOCALIO */
191 
192 	clp->cl_principal = "*";
193 	clp->cl_xprtsec = cl_init->xprtsec;
194 	return clp;
195 
196 error_cleanup:
197 	put_nfs_version(clp->cl_nfs_mod);
198 error_dealloc:
199 	kfree(clp);
200 error_0:
201 	return ERR_PTR(err);
202 }
203 EXPORT_SYMBOL_GPL(nfs_alloc_client);
204 
205 #if IS_ENABLED(CONFIG_NFS_V4)
206 static void nfs_cleanup_cb_ident_idr(struct net *net)
207 {
208 	struct nfs_net *nn = net_generic(net, nfs_net_id);
209 
210 	idr_destroy(&nn->cb_ident_idr);
211 }
212 
213 /* nfs_client_lock held */
214 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
215 {
216 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
217 
218 	if (clp->cl_cb_ident)
219 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
220 }
221 
222 static void pnfs_init_server(struct nfs_server *server)
223 {
224 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
225 }
226 
227 #else
228 static void nfs_cleanup_cb_ident_idr(struct net *net)
229 {
230 }
231 
232 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
233 {
234 }
235 
236 static void pnfs_init_server(struct nfs_server *server)
237 {
238 }
239 
240 #endif /* CONFIG_NFS_V4 */
241 
242 /*
243  * Destroy a shared client record
244  */
245 void nfs_free_client(struct nfs_client *clp)
246 {
247 	nfs_localio_disable_client(clp);
248 
249 	/* -EIO all pending I/O */
250 	if (!IS_ERR(clp->cl_rpcclient))
251 		rpc_shutdown_client(clp->cl_rpcclient);
252 
253 	put_net_track(clp->cl_net, &clp->cl_ns_tracker);
254 	put_nfs_version(clp->cl_nfs_mod);
255 	kfree(clp->cl_hostname);
256 	kfree(clp->cl_acceptor);
257 	kfree_rcu(clp, rcu);
258 }
259 EXPORT_SYMBOL_GPL(nfs_free_client);
260 
261 /*
262  * Release a reference to a shared client record
263  */
264 void nfs_put_client(struct nfs_client *clp)
265 {
266 	struct nfs_net *nn;
267 
268 	if (!clp)
269 		return;
270 
271 	nn = net_generic(clp->cl_net, nfs_net_id);
272 
273 	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
274 		list_del(&clp->cl_share_link);
275 		nfs_cb_idr_remove_locked(clp);
276 		spin_unlock(&nn->nfs_client_lock);
277 
278 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
279 
280 		clp->rpc_ops->free_client(clp);
281 	}
282 }
283 EXPORT_SYMBOL_GPL(nfs_put_client);
284 
285 /*
286  * Find an nfs_client on the list that matches the initialisation data
287  * that is supplied.
288  */
289 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
290 {
291 	struct nfs_client *clp;
292 	const struct sockaddr *sap = (struct sockaddr *)data->addr;
293 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
294 	int error;
295 
296 again:
297 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
298 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
299 		/* Don't match clients that failed to initialise properly */
300 		if (clp->cl_cons_state < 0)
301 			continue;
302 
303 		/* If a client is still initializing then we need to wait */
304 		if (clp->cl_cons_state > NFS_CS_READY) {
305 			refcount_inc(&clp->cl_count);
306 			spin_unlock(&nn->nfs_client_lock);
307 			error = nfs_wait_client_init_complete(clp);
308 			nfs_put_client(clp);
309 			spin_lock(&nn->nfs_client_lock);
310 			if (error < 0)
311 				return ERR_PTR(error);
312 			goto again;
313 		}
314 
315 		/* Different NFS versions cannot share the same nfs_client */
316 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
317 			continue;
318 
319 		if (clp->cl_proto != data->proto)
320 			continue;
321 		/* Match nfsv4 minorversion */
322 		if (clp->cl_minorversion != data->minorversion)
323 			continue;
324 
325 		/* Match request for a dedicated DS */
326 		if (test_bit(NFS_CS_DS, &data->init_flags) !=
327 		    test_bit(NFS_CS_DS, &clp->cl_flags))
328 			continue;
329 
330 		/* Match the full socket address */
331 		if (!rpc_cmp_addr_port(sap, clap))
332 			/* Match all xprt_switch full socket addresses */
333 			if (IS_ERR(clp->cl_rpcclient) ||
334                             !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
335 							   sap))
336 				continue;
337 
338 		/* Match the xprt security policy */
339 		if (clp->cl_xprtsec.policy != data->xprtsec.policy)
340 			continue;
341 
342 		refcount_inc(&clp->cl_count);
343 		return clp;
344 	}
345 	return NULL;
346 }
347 
348 /*
349  * Return true if @clp is done initializing, false if still working on it.
350  *
351  * Use nfs_client_init_status to check if it was successful.
352  */
353 bool nfs_client_init_is_complete(const struct nfs_client *clp)
354 {
355 	return clp->cl_cons_state <= NFS_CS_READY;
356 }
357 EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
358 
359 /*
360  * Return 0 if @clp was successfully initialized, -errno otherwise.
361  *
362  * This must be called *after* nfs_client_init_is_complete() returns true,
363  * otherwise it will pop WARN_ON_ONCE and return -EINVAL
364  */
365 int nfs_client_init_status(const struct nfs_client *clp)
366 {
367 	/* called without checking nfs_client_init_is_complete */
368 	if (clp->cl_cons_state > NFS_CS_READY) {
369 		WARN_ON_ONCE(1);
370 		return -EINVAL;
371 	}
372 	return clp->cl_cons_state;
373 }
374 EXPORT_SYMBOL_GPL(nfs_client_init_status);
375 
376 int nfs_wait_client_init_complete(const struct nfs_client *clp)
377 {
378 	return wait_event_killable(nfs_client_active_wq,
379 			nfs_client_init_is_complete(clp));
380 }
381 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
382 
383 /*
384  * Found an existing client.  Make sure it's ready before returning.
385  */
386 static struct nfs_client *
387 nfs_found_client(const struct nfs_client_initdata *cl_init,
388 		 struct nfs_client *clp)
389 {
390 	int error;
391 
392 	error = nfs_wait_client_init_complete(clp);
393 	if (error < 0) {
394 		nfs_put_client(clp);
395 		return ERR_PTR(-ERESTARTSYS);
396 	}
397 
398 	if (clp->cl_cons_state < NFS_CS_READY) {
399 		error = clp->cl_cons_state;
400 		nfs_put_client(clp);
401 		return ERR_PTR(error);
402 	}
403 
404 	smp_rmb();
405 	return clp;
406 }
407 
408 /*
409  * Look up a client by IP address and protocol version
410  * - creates a new record if one doesn't yet exist
411  */
412 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
413 {
414 	struct nfs_client *clp, *new = NULL;
415 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
416 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
417 
418 	if (cl_init->hostname == NULL) {
419 		WARN_ON(1);
420 		return ERR_PTR(-EINVAL);
421 	}
422 
423 	/* see if the client already exists */
424 	do {
425 		spin_lock(&nn->nfs_client_lock);
426 
427 		clp = nfs_match_client(cl_init);
428 		if (clp) {
429 			spin_unlock(&nn->nfs_client_lock);
430 			if (new)
431 				new->rpc_ops->free_client(new);
432 			if (IS_ERR(clp))
433 				return clp;
434 			return nfs_found_client(cl_init, clp);
435 		}
436 		if (new) {
437 			list_add_tail(&new->cl_share_link,
438 					&nn->nfs_client_list);
439 			spin_unlock(&nn->nfs_client_lock);
440 			new = rpc_ops->init_client(new, cl_init);
441 			if (!IS_ERR(new))
442 				 nfs_local_probe_async(new);
443 			return new;
444 		}
445 
446 		spin_unlock(&nn->nfs_client_lock);
447 
448 		new = rpc_ops->alloc_client(cl_init);
449 	} while (!IS_ERR(new));
450 
451 	return new;
452 }
453 EXPORT_SYMBOL_GPL(nfs_get_client);
454 
455 /*
456  * Mark a server as ready or failed
457  */
458 void nfs_mark_client_ready(struct nfs_client *clp, int state)
459 {
460 	smp_wmb();
461 	clp->cl_cons_state = state;
462 	wake_up_all(&nfs_client_active_wq);
463 }
464 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
465 
466 /*
467  * Initialise the timeout values for a connection
468  */
469 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
470 				    int timeo, int retrans)
471 {
472 	to->to_initval = timeo * HZ / 10;
473 	to->to_retries = retrans;
474 
475 	switch (proto) {
476 	case XPRT_TRANSPORT_TCP:
477 	case XPRT_TRANSPORT_TCP_TLS:
478 	case XPRT_TRANSPORT_RDMA:
479 		if (retrans == NFS_UNSPEC_RETRANS)
480 			to->to_retries = NFS_DEF_TCP_RETRANS;
481 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
482 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
483 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
484 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
485 		to->to_increment = to->to_initval;
486 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
487 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
488 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
489 		if (to->to_maxval < to->to_initval)
490 			to->to_maxval = to->to_initval;
491 		to->to_exponential = 0;
492 		break;
493 	case XPRT_TRANSPORT_UDP:
494 		if (retrans == NFS_UNSPEC_RETRANS)
495 			to->to_retries = NFS_DEF_UDP_RETRANS;
496 		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
497 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
498 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
499 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
500 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
501 		to->to_exponential = 1;
502 		break;
503 	default:
504 		BUG();
505 	}
506 }
507 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
508 
509 /*
510  * Create an RPC client handle
511  */
512 int nfs_create_rpc_client(struct nfs_client *clp,
513 			  const struct nfs_client_initdata *cl_init,
514 			  rpc_authflavor_t flavor)
515 {
516 	struct nfs_net		*nn = net_generic(clp->cl_net, nfs_net_id);
517 	struct rpc_clnt		*clnt = NULL;
518 	struct rpc_create_args args = {
519 		.net		= clp->cl_net,
520 		.protocol	= clp->cl_proto,
521 		.nconnect	= clp->cl_nconnect,
522 		.address	= (struct sockaddr *)&clp->cl_addr,
523 		.addrsize	= clp->cl_addrlen,
524 		.timeout	= cl_init->timeparms,
525 		.servername	= clp->cl_hostname,
526 		.nodename	= cl_init->nodename,
527 		.program	= &nfs_program,
528 		.stats		= &nn->rpcstats,
529 		.version	= clp->rpc_ops->version,
530 		.authflavor	= flavor,
531 		.cred		= cl_init->cred,
532 		.xprtsec	= cl_init->xprtsec,
533 		.connect_timeout = cl_init->connect_timeout,
534 		.reconnect_timeout = cl_init->reconnect_timeout,
535 	};
536 
537 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
538 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
539 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
540 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
541 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
542 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
543 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
544 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
545 	if (test_bit(NFS_CS_NOPING, &clp->cl_flags))
546 		args.flags |= RPC_CLNT_CREATE_NOPING;
547 	if (test_bit(NFS_CS_REUSEPORT, &clp->cl_flags))
548 		args.flags |= RPC_CLNT_CREATE_REUSEPORT;
549 	if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
550 		args.flags |= RPC_CLNT_CREATE_NETUNREACH_FATAL;
551 
552 	if (!IS_ERR(clp->cl_rpcclient))
553 		return 0;
554 
555 	clnt = rpc_create(&args);
556 	if (IS_ERR(clnt)) {
557 		dprintk("%s: cannot create RPC client. Error = %ld\n",
558 				__func__, PTR_ERR(clnt));
559 		return PTR_ERR(clnt);
560 	}
561 
562 	clnt->cl_principal = clp->cl_principal;
563 	clp->cl_rpcclient = clnt;
564 	clnt->cl_max_connect = clp->cl_max_connect;
565 	return 0;
566 }
567 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
568 
569 /*
570  * Version 2 or 3 client destruction
571  */
572 static void nfs_destroy_server(struct nfs_server *server)
573 {
574 	if (server->nlm_host)
575 		nlmclnt_done(server->nlm_host);
576 }
577 
578 /*
579  * Version 2 or 3 lockd setup
580  */
581 static int nfs_start_lockd(struct nfs_server *server)
582 {
583 	struct nlm_host *host;
584 	struct nfs_client *clp = server->nfs_client;
585 	struct nlmclnt_initdata nlm_init = {
586 		.hostname	= clp->cl_hostname,
587 		.address	= (struct sockaddr *)&clp->cl_addr,
588 		.addrlen	= clp->cl_addrlen,
589 		.nfs_version	= clp->rpc_ops->version,
590 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
591 					1 : 0,
592 		.net		= clp->cl_net,
593 		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
594 		.cred		= server->cred,
595 	};
596 
597 	if (nlm_init.nfs_version > 3)
598 		return 0;
599 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
600 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
601 		return 0;
602 
603 	switch (clp->cl_proto) {
604 		default:
605 			nlm_init.protocol = IPPROTO_TCP;
606 			break;
607 #ifndef CONFIG_NFS_DISABLE_UDP_SUPPORT
608 		case XPRT_TRANSPORT_UDP:
609 			nlm_init.protocol = IPPROTO_UDP;
610 #endif
611 	}
612 
613 	host = nlmclnt_init(&nlm_init);
614 	if (IS_ERR(host))
615 		return PTR_ERR(host);
616 
617 	server->nlm_host = host;
618 	server->destroy = nfs_destroy_server;
619 	nfs_sysfs_link_rpc_client(server, nlmclnt_rpc_clnt(host), NULL);
620 	return 0;
621 }
622 
623 /*
624  * Create a general RPC client
625  */
626 int nfs_init_server_rpcclient(struct nfs_server *server,
627 		const struct rpc_timeout *timeo,
628 		rpc_authflavor_t pseudoflavour)
629 {
630 	struct nfs_client *clp = server->nfs_client;
631 
632 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
633 							pseudoflavour);
634 	if (IS_ERR(server->client)) {
635 		dprintk("%s: couldn't create rpc_client!\n", __func__);
636 		return PTR_ERR(server->client);
637 	}
638 
639 	memcpy(&server->client->cl_timeout_default,
640 			timeo,
641 			sizeof(server->client->cl_timeout_default));
642 	server->client->cl_timeout = &server->client->cl_timeout_default;
643 	server->client->cl_softrtry = 0;
644 	if (server->flags & NFS_MOUNT_SOFTERR)
645 		server->client->cl_softerr = 1;
646 	if (server->flags & NFS_MOUNT_SOFT)
647 		server->client->cl_softrtry = 1;
648 
649 	nfs_sysfs_link_rpc_client(server, server->client, NULL);
650 	return 0;
651 }
652 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
653 
654 /**
655  * nfs_init_client - Initialise an NFS2 or NFS3 client
656  *
657  * @clp: nfs_client to initialise
658  * @cl_init: Initialisation parameters
659  *
660  * Returns pointer to an NFS client, or an ERR_PTR value.
661  */
662 struct nfs_client *nfs_init_client(struct nfs_client *clp,
663 				   const struct nfs_client_initdata *cl_init)
664 {
665 	int error;
666 
667 	/* the client is already initialised */
668 	if (clp->cl_cons_state == NFS_CS_READY)
669 		return clp;
670 
671 	/*
672 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
673 	 * - RFC 2623, sec 2.3.2
674 	 */
675 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
676 	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
677 	if (error < 0) {
678 		nfs_put_client(clp);
679 		clp = ERR_PTR(error);
680 	}
681 	return clp;
682 }
683 EXPORT_SYMBOL_GPL(nfs_init_client);
684 
685 /*
686  * Create a version 2 or 3 client
687  */
688 static int nfs_init_server(struct nfs_server *server,
689 			   const struct fs_context *fc)
690 {
691 	const struct nfs_fs_context *ctx = nfs_fc2context(fc);
692 	struct rpc_timeout timeparms;
693 	struct nfs_client_initdata cl_init = {
694 		.hostname = ctx->nfs_server.hostname,
695 		.addr = &ctx->nfs_server._address,
696 		.addrlen = ctx->nfs_server.addrlen,
697 		.nfs_mod = ctx->nfs_mod,
698 		.proto = ctx->nfs_server.protocol,
699 		.net = fc->net_ns,
700 		.timeparms = &timeparms,
701 		.cred = server->cred,
702 		.nconnect = ctx->nfs_server.nconnect,
703 		.init_flags = (1UL << NFS_CS_REUSEPORT),
704 		.xprtsec = ctx->xprtsec,
705 	};
706 	struct nfs_client *clp;
707 	int error;
708 
709 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
710 				ctx->timeo, ctx->retrans);
711 	if (ctx->flags & NFS_MOUNT_NORESVPORT)
712 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
713 
714 	if (ctx->flags & NFS_MOUNT_NETUNREACH_FATAL)
715 		__set_bit(NFS_CS_NETUNREACH_FATAL, &cl_init.init_flags);
716 
717 	/* Allocate or find a client reference we can use */
718 	clp = nfs_get_client(&cl_init);
719 	if (IS_ERR(clp))
720 		return PTR_ERR(clp);
721 
722 	server->nfs_client = clp;
723 	nfs_sysfs_add_server(server);
724 	nfs_sysfs_link_rpc_client(server, clp->cl_rpcclient, "_state");
725 
726 	/* Initialise the client representation from the mount data */
727 	server->flags = ctx->flags;
728 	server->options = ctx->options;
729 	server->caps |= NFS_CAP_HARDLINKS | NFS_CAP_SYMLINKS;
730 
731 	switch (clp->rpc_ops->version) {
732 	case 2:
733 		server->fattr_valid = NFS_ATTR_FATTR_V2;
734 		break;
735 	case 3:
736 		server->fattr_valid = NFS_ATTR_FATTR_V3;
737 		break;
738 	default:
739 		server->fattr_valid = NFS_ATTR_FATTR_V4;
740 	}
741 
742 	if (ctx->rsize)
743 		server->rsize = nfs_io_size(ctx->rsize, clp->cl_proto);
744 	if (ctx->wsize)
745 		server->wsize = nfs_io_size(ctx->wsize, clp->cl_proto);
746 
747 	server->acregmin = ctx->acregmin * HZ;
748 	server->acregmax = ctx->acregmax * HZ;
749 	server->acdirmin = ctx->acdirmin * HZ;
750 	server->acdirmax = ctx->acdirmax * HZ;
751 
752 	/* Start lockd here, before we might error out */
753 	error = nfs_start_lockd(server);
754 	if (error < 0)
755 		goto error;
756 
757 	server->port = ctx->nfs_server.port;
758 	server->auth_info = ctx->auth_info;
759 
760 	error = nfs_init_server_rpcclient(server, &timeparms,
761 					  ctx->selected_flavor);
762 	if (error < 0)
763 		goto error;
764 
765 	/* Preserve the values of mount_server-related mount options */
766 	if (ctx->mount_server.addrlen) {
767 		memcpy(&server->mountd_address, &ctx->mount_server.address,
768 			ctx->mount_server.addrlen);
769 		server->mountd_addrlen = ctx->mount_server.addrlen;
770 	}
771 	server->mountd_version = ctx->mount_server.version;
772 	server->mountd_port = ctx->mount_server.port;
773 	server->mountd_protocol = ctx->mount_server.protocol;
774 
775 	server->namelen  = ctx->namlen;
776 	return 0;
777 
778 error:
779 	server->nfs_client = NULL;
780 	nfs_put_client(clp);
781 	return error;
782 }
783 
784 /*
785  * Load up the server record from information gained in an fsinfo record
786  */
787 static void nfs_server_set_fsinfo(struct nfs_server *server,
788 				  struct nfs_fsinfo *fsinfo)
789 {
790 	struct nfs_client *clp = server->nfs_client;
791 	unsigned long max_rpc_payload, raw_max_rpc_payload;
792 
793 	/* Work out a lot of parameters */
794 	if (server->rsize == 0)
795 		server->rsize = nfs_io_size(fsinfo->rtpref, clp->cl_proto);
796 	if (server->wsize == 0)
797 		server->wsize = nfs_io_size(fsinfo->wtpref, clp->cl_proto);
798 
799 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
800 		server->rsize = nfs_io_size(fsinfo->rtmax, clp->cl_proto);
801 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
802 		server->wsize = nfs_io_size(fsinfo->wtmax, clp->cl_proto);
803 
804 	raw_max_rpc_payload = rpc_max_payload(server->client);
805 	max_rpc_payload = nfs_block_size(raw_max_rpc_payload, NULL);
806 
807 	if (server->rsize > max_rpc_payload)
808 		server->rsize = max_rpc_payload;
809 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
810 		server->rsize = NFS_MAX_FILE_IO_SIZE;
811 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
812 
813 	if (server->wsize > max_rpc_payload)
814 		server->wsize = max_rpc_payload;
815 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
816 		server->wsize = NFS_MAX_FILE_IO_SIZE;
817 	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
818 
819 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
820 
821 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
822 	if (server->dtsize > NFS_MAX_FILE_IO_SIZE)
823 		server->dtsize = NFS_MAX_FILE_IO_SIZE;
824 	if (server->dtsize > server->rsize)
825 		server->dtsize = server->rsize;
826 
827 	if (server->flags & NFS_MOUNT_NOAC) {
828 		server->acregmin = server->acregmax = 0;
829 		server->acdirmin = server->acdirmax = 0;
830 	}
831 
832 	server->maxfilesize = fsinfo->maxfilesize;
833 
834 	server->time_delta = fsinfo->time_delta;
835 	server->change_attr_type = fsinfo->change_attr_type;
836 
837 	server->clone_blksize = fsinfo->clone_blksize;
838 	/* We're airborne Set socket buffersize */
839 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
840 
841 #ifdef CONFIG_NFS_V4_2
842 	/*
843 	 * Defaults until limited by the session parameters.
844 	 */
845 	server->gxasize = min_t(unsigned int, raw_max_rpc_payload,
846 				XATTR_SIZE_MAX);
847 	server->sxasize = min_t(unsigned int, raw_max_rpc_payload,
848 				XATTR_SIZE_MAX);
849 	server->lxasize = min_t(unsigned int, raw_max_rpc_payload,
850 				nfs42_listxattr_xdrsize(XATTR_LIST_MAX));
851 
852 	if (fsinfo->xattr_support)
853 		server->caps |= NFS_CAP_XATTR;
854 #endif
855 }
856 
857 /*
858  * Probe filesystem information, including the FSID on v2/v3
859  */
860 static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
861 {
862 	struct nfs_fsinfo fsinfo;
863 	struct nfs_client *clp = server->nfs_client;
864 	int error;
865 
866 	if (clp->rpc_ops->set_capabilities != NULL) {
867 		error = clp->rpc_ops->set_capabilities(server, mntfh);
868 		if (error < 0)
869 			return error;
870 	}
871 
872 	fsinfo.fattr = fattr;
873 	fsinfo.nlayouttypes = 0;
874 	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
875 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
876 	if (error < 0)
877 		return error;
878 
879 	nfs_server_set_fsinfo(server, &fsinfo);
880 
881 	/* Get some general file system info */
882 	if (server->namelen == 0) {
883 		struct nfs_pathconf pathinfo;
884 
885 		pathinfo.fattr = fattr;
886 		nfs_fattr_init(fattr);
887 
888 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
889 			server->namelen = pathinfo.max_namelen;
890 	}
891 
892 	if (clp->rpc_ops->discover_trunking != NULL &&
893 			(server->caps & NFS_CAP_FS_LOCATIONS &&
894 			 (server->flags & NFS_MOUNT_TRUNK_DISCOVERY))) {
895 		error = clp->rpc_ops->discover_trunking(server, mntfh);
896 		if (error < 0)
897 			return error;
898 	}
899 
900 	return 0;
901 }
902 
903 /*
904  * Grab the destination's particulars, including lease expiry time.
905  *
906  * Returns zero if probe succeeded and retrieved FSID matches the FSID
907  * we have cached.
908  */
909 int nfs_probe_server(struct nfs_server *server, struct nfs_fh *mntfh)
910 {
911 	struct nfs_fattr *fattr;
912 	int error;
913 
914 	fattr = nfs_alloc_fattr();
915 	if (fattr == NULL)
916 		return -ENOMEM;
917 
918 	/* Sanity: the probe won't work if the destination server
919 	 * does not recognize the migrated FH. */
920 	error = nfs_probe_fsinfo(server, mntfh, fattr);
921 
922 	nfs_free_fattr(fattr);
923 	return error;
924 }
925 EXPORT_SYMBOL_GPL(nfs_probe_server);
926 
927 /*
928  * Copy useful information when duplicating a server record
929  */
930 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
931 {
932 	target->flags = source->flags;
933 	target->rsize = source->rsize;
934 	target->wsize = source->wsize;
935 	target->acregmin = source->acregmin;
936 	target->acregmax = source->acregmax;
937 	target->acdirmin = source->acdirmin;
938 	target->acdirmax = source->acdirmax;
939 	target->caps = source->caps;
940 	target->options = source->options;
941 	target->auth_info = source->auth_info;
942 	target->port = source->port;
943 }
944 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
945 
946 void nfs_server_insert_lists(struct nfs_server *server)
947 {
948 	struct nfs_client *clp = server->nfs_client;
949 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
950 
951 	spin_lock(&nn->nfs_client_lock);
952 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
953 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
954 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
955 	spin_unlock(&nn->nfs_client_lock);
956 
957 }
958 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
959 
960 void nfs_server_remove_lists(struct nfs_server *server)
961 {
962 	struct nfs_client *clp = server->nfs_client;
963 	struct nfs_net *nn;
964 
965 	if (clp == NULL)
966 		return;
967 	nn = net_generic(clp->cl_net, nfs_net_id);
968 	spin_lock(&nn->nfs_client_lock);
969 	list_del_rcu(&server->client_link);
970 	if (list_empty(&clp->cl_superblocks))
971 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
972 	list_del(&server->master_link);
973 	spin_unlock(&nn->nfs_client_lock);
974 
975 	synchronize_rcu();
976 }
977 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
978 
979 static DEFINE_IDA(s_sysfs_ids);
980 
981 /*
982  * Allocate and initialise a server record
983  */
984 struct nfs_server *nfs_alloc_server(void)
985 {
986 	struct nfs_server *server;
987 
988 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
989 	if (!server)
990 		return NULL;
991 
992 	server->s_sysfs_id = ida_alloc(&s_sysfs_ids, GFP_KERNEL);
993 	if (server->s_sysfs_id < 0) {
994 		kfree(server);
995 		return NULL;
996 	}
997 
998 	server->client = server->client_acl = ERR_PTR(-EINVAL);
999 
1000 	/* Zero out the NFS state stuff */
1001 	INIT_LIST_HEAD(&server->client_link);
1002 	INIT_LIST_HEAD(&server->master_link);
1003 	INIT_LIST_HEAD(&server->delegations);
1004 	INIT_LIST_HEAD(&server->layouts);
1005 	INIT_LIST_HEAD(&server->state_owners_lru);
1006 	INIT_LIST_HEAD(&server->ss_copies);
1007 	INIT_LIST_HEAD(&server->ss_src_copies);
1008 
1009 	atomic_set(&server->active, 0);
1010 
1011 	server->io_stats = nfs_alloc_iostats();
1012 	if (!server->io_stats) {
1013 		kfree(server);
1014 		return NULL;
1015 	}
1016 
1017 	server->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
1018 
1019 	init_waitqueue_head(&server->write_congestion_wait);
1020 	atomic_long_set(&server->writeback, 0);
1021 
1022 	atomic64_set(&server->owner_ctr, 0);
1023 
1024 	pnfs_init_server(server);
1025 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
1026 
1027 	return server;
1028 }
1029 EXPORT_SYMBOL_GPL(nfs_alloc_server);
1030 
1031 static void delayed_free(struct rcu_head *p)
1032 {
1033 	struct nfs_server *server = container_of(p, struct nfs_server, rcu);
1034 
1035 	nfs_free_iostats(server->io_stats);
1036 	kfree(server);
1037 }
1038 
1039 /*
1040  * Free up a server record
1041  */
1042 void nfs_free_server(struct nfs_server *server)
1043 {
1044 	nfs_server_remove_lists(server);
1045 
1046 	if (server->destroy != NULL)
1047 		server->destroy(server);
1048 
1049 	if (!IS_ERR(server->client_acl))
1050 		rpc_shutdown_client(server->client_acl);
1051 	if (!IS_ERR(server->client))
1052 		rpc_shutdown_client(server->client);
1053 
1054 	nfs_put_client(server->nfs_client);
1055 
1056 	if (server->kobj.state_initialized) {
1057 		nfs_sysfs_remove_server(server);
1058 		kobject_put(&server->kobj);
1059 	}
1060 	ida_free(&s_sysfs_ids, server->s_sysfs_id);
1061 
1062 	put_cred(server->cred);
1063 	nfs_release_automount_timer();
1064 	call_rcu(&server->rcu, delayed_free);
1065 }
1066 EXPORT_SYMBOL_GPL(nfs_free_server);
1067 
1068 /*
1069  * Create a version 2 or 3 volume record
1070  * - keyed on server and FSID
1071  */
1072 struct nfs_server *nfs_create_server(struct fs_context *fc)
1073 {
1074 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1075 	struct nfs_server *server;
1076 	struct nfs_fattr *fattr;
1077 	int error;
1078 
1079 	server = nfs_alloc_server();
1080 	if (!server)
1081 		return ERR_PTR(-ENOMEM);
1082 
1083 	server->cred = get_cred(fc->cred);
1084 
1085 	error = -ENOMEM;
1086 	fattr = nfs_alloc_fattr();
1087 	if (fattr == NULL)
1088 		goto error;
1089 
1090 	/* Get a client representation */
1091 	error = nfs_init_server(server, fc);
1092 	if (error < 0)
1093 		goto error;
1094 
1095 	/* Probe the root fh to retrieve its FSID */
1096 	error = nfs_probe_fsinfo(server, ctx->mntfh, fattr);
1097 	if (error < 0)
1098 		goto error;
1099 	if (server->nfs_client->rpc_ops->version == 3) {
1100 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
1101 			server->namelen = NFS3_MAXNAMLEN;
1102 		if (!(ctx->flags & NFS_MOUNT_NORDIRPLUS))
1103 			server->caps |= NFS_CAP_READDIRPLUS;
1104 	} else {
1105 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
1106 			server->namelen = NFS2_MAXNAMLEN;
1107 	}
1108 	/* Linux 'subtree_check' borkenness mandates this setting */
1109 	server->fh_expire_type = NFS_FH_VOL_RENAME;
1110 
1111 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
1112 		error = ctx->nfs_mod->rpc_ops->getattr(server, ctx->mntfh,
1113 						       fattr, NULL);
1114 		if (error < 0) {
1115 			dprintk("nfs_create_server: getattr error = %d\n", -error);
1116 			goto error;
1117 		}
1118 	}
1119 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
1120 
1121 	dprintk("Server FSID: %llx:%llx\n",
1122 		(unsigned long long) server->fsid.major,
1123 		(unsigned long long) server->fsid.minor);
1124 
1125 	nfs_server_insert_lists(server);
1126 	server->mount_time = jiffies;
1127 	nfs_free_fattr(fattr);
1128 	return server;
1129 
1130 error:
1131 	nfs_free_fattr(fattr);
1132 	nfs_free_server(server);
1133 	return ERR_PTR(error);
1134 }
1135 EXPORT_SYMBOL_GPL(nfs_create_server);
1136 
1137 /*
1138  * Clone an NFS2, NFS3 or NFS4 server record
1139  */
1140 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1141 				    struct nfs_fh *fh,
1142 				    struct nfs_fattr *fattr,
1143 				    rpc_authflavor_t flavor)
1144 {
1145 	struct nfs_server *server;
1146 	int error;
1147 
1148 	server = nfs_alloc_server();
1149 	if (!server)
1150 		return ERR_PTR(-ENOMEM);
1151 
1152 	server->cred = get_cred(source->cred);
1153 
1154 	/* Copy data from the source */
1155 	server->nfs_client = source->nfs_client;
1156 	server->destroy = source->destroy;
1157 	refcount_inc(&server->nfs_client->cl_count);
1158 	nfs_server_copy_userdata(server, source);
1159 
1160 	server->fsid = fattr->fsid;
1161 
1162 	nfs_sysfs_add_server(server);
1163 
1164 	nfs_sysfs_link_rpc_client(server,
1165 		server->nfs_client->cl_rpcclient, "_state");
1166 
1167 	error = nfs_init_server_rpcclient(server,
1168 			source->client->cl_timeout,
1169 			flavor);
1170 	if (error < 0)
1171 		goto out_free_server;
1172 
1173 	/* probe the filesystem info for this server filesystem */
1174 	error = nfs_probe_server(server, fh);
1175 	if (error < 0)
1176 		goto out_free_server;
1177 
1178 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1179 		server->namelen = NFS4_MAXNAMLEN;
1180 
1181 	error = nfs_start_lockd(server);
1182 	if (error < 0)
1183 		goto out_free_server;
1184 
1185 	nfs_server_insert_lists(server);
1186 	server->mount_time = jiffies;
1187 
1188 	return server;
1189 
1190 out_free_server:
1191 	nfs_free_server(server);
1192 	return ERR_PTR(error);
1193 }
1194 EXPORT_SYMBOL_GPL(nfs_clone_server);
1195 
1196 void nfs_clients_init(struct net *net)
1197 {
1198 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1199 
1200 	INIT_LIST_HEAD(&nn->nfs_client_list);
1201 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1202 #if IS_ENABLED(CONFIG_NFS_V4)
1203 	idr_init(&nn->cb_ident_idr);
1204 #endif
1205 #if IS_ENABLED(CONFIG_NFS_V4_1)
1206 	INIT_LIST_HEAD(&nn->nfs4_data_server_cache);
1207 	spin_lock_init(&nn->nfs4_data_server_lock);
1208 #endif
1209 	spin_lock_init(&nn->nfs_client_lock);
1210 	nn->boot_time = ktime_get_real();
1211 	memset(&nn->rpcstats, 0, sizeof(nn->rpcstats));
1212 	nn->rpcstats.program = &nfs_program;
1213 
1214 	nfs_netns_sysfs_setup(nn, net);
1215 }
1216 
1217 void nfs_clients_exit(struct net *net)
1218 {
1219 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1220 
1221 	nfs_netns_sysfs_destroy(nn);
1222 	nfs_cleanup_cb_ident_idr(net);
1223 	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));
1224 	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));
1225 #if IS_ENABLED(CONFIG_NFS_V4_1)
1226 	WARN_ON_ONCE(!list_empty(&nn->nfs4_data_server_cache));
1227 #endif
1228 }
1229 
1230 #ifdef CONFIG_PROC_FS
1231 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1232 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1233 static void nfs_server_list_stop(struct seq_file *p, void *v);
1234 static int nfs_server_list_show(struct seq_file *m, void *v);
1235 
1236 static const struct seq_operations nfs_server_list_ops = {
1237 	.start	= nfs_server_list_start,
1238 	.next	= nfs_server_list_next,
1239 	.stop	= nfs_server_list_stop,
1240 	.show	= nfs_server_list_show,
1241 };
1242 
1243 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1244 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1245 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1246 static int nfs_volume_list_show(struct seq_file *m, void *v);
1247 
1248 static const struct seq_operations nfs_volume_list_ops = {
1249 	.start	= nfs_volume_list_start,
1250 	.next	= nfs_volume_list_next,
1251 	.stop	= nfs_volume_list_stop,
1252 	.show	= nfs_volume_list_show,
1253 };
1254 
1255 /*
1256  * set up the iterator to start reading from the server list and return the first item
1257  */
1258 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1259 				__acquires(&nn->nfs_client_lock)
1260 {
1261 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1262 
1263 	/* lock the list against modification */
1264 	spin_lock(&nn->nfs_client_lock);
1265 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1266 }
1267 
1268 /*
1269  * move to next server
1270  */
1271 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1272 {
1273 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1274 
1275 	return seq_list_next(v, &nn->nfs_client_list, pos);
1276 }
1277 
1278 /*
1279  * clean up after reading from the transports list
1280  */
1281 static void nfs_server_list_stop(struct seq_file *p, void *v)
1282 				__releases(&nn->nfs_client_lock)
1283 {
1284 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1285 
1286 	spin_unlock(&nn->nfs_client_lock);
1287 }
1288 
1289 /*
1290  * display a header line followed by a load of call lines
1291  */
1292 static int nfs_server_list_show(struct seq_file *m, void *v)
1293 {
1294 	struct nfs_client *clp;
1295 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1296 
1297 	/* display header on line 1 */
1298 	if (v == &nn->nfs_client_list) {
1299 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1300 		return 0;
1301 	}
1302 
1303 	/* display one transport per line on subsequent lines */
1304 	clp = list_entry(v, struct nfs_client, cl_share_link);
1305 
1306 	/* Check if the client is initialized */
1307 	if (clp->cl_cons_state != NFS_CS_READY)
1308 		return 0;
1309 
1310 	rcu_read_lock();
1311 	seq_printf(m, "v%u %s %s %3d %s\n",
1312 		   clp->rpc_ops->version,
1313 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1314 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1315 		   refcount_read(&clp->cl_count),
1316 		   clp->cl_hostname);
1317 	rcu_read_unlock();
1318 
1319 	return 0;
1320 }
1321 
1322 /*
1323  * set up the iterator to start reading from the volume list and return the first item
1324  */
1325 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1326 				__acquires(&nn->nfs_client_lock)
1327 {
1328 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1329 
1330 	/* lock the list against modification */
1331 	spin_lock(&nn->nfs_client_lock);
1332 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1333 }
1334 
1335 /*
1336  * move to next volume
1337  */
1338 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1339 {
1340 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1341 
1342 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1343 }
1344 
1345 /*
1346  * clean up after reading from the transports list
1347  */
1348 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1349 				__releases(&nn->nfs_client_lock)
1350 {
1351 	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
1352 
1353 	spin_unlock(&nn->nfs_client_lock);
1354 }
1355 
1356 /*
1357  * display a header line followed by a load of call lines
1358  */
1359 static int nfs_volume_list_show(struct seq_file *m, void *v)
1360 {
1361 	struct nfs_server *server;
1362 	struct nfs_client *clp;
1363 	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
1364 	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
1365 	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
1366 
1367 	/* display header on line 1 */
1368 	if (v == &nn->nfs_volume_list) {
1369 		seq_puts(m, "NV SERVER   PORT DEV          FSID"
1370 			    "                              FSC\n");
1371 		return 0;
1372 	}
1373 	/* display one transport per line on subsequent lines */
1374 	server = list_entry(v, struct nfs_server, master_link);
1375 	clp = server->nfs_client;
1376 
1377 	snprintf(dev, sizeof(dev), "%u:%u",
1378 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1379 
1380 	snprintf(fsid, sizeof(fsid), "%llx:%llx",
1381 		 (unsigned long long) server->fsid.major,
1382 		 (unsigned long long) server->fsid.minor);
1383 
1384 	rcu_read_lock();
1385 	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
1386 		   clp->rpc_ops->version,
1387 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1388 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1389 		   dev,
1390 		   fsid,
1391 		   nfs_server_fscache_state(server));
1392 	rcu_read_unlock();
1393 
1394 	return 0;
1395 }
1396 
1397 int nfs_fs_proc_net_init(struct net *net)
1398 {
1399 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1400 	struct proc_dir_entry *p;
1401 
1402 	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
1403 	if (!nn->proc_nfsfs)
1404 		goto error_0;
1405 
1406 	/* a file of servers with which we're dealing */
1407 	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1408 			&nfs_server_list_ops, sizeof(struct seq_net_private));
1409 	if (!p)
1410 		goto error_1;
1411 
1412 	/* a file of volumes that we have mounted */
1413 	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
1414 			&nfs_volume_list_ops, sizeof(struct seq_net_private));
1415 	if (!p)
1416 		goto error_1;
1417 	return 0;
1418 
1419 error_1:
1420 	remove_proc_subtree("nfsfs", net->proc_net);
1421 error_0:
1422 	return -ENOMEM;
1423 }
1424 
1425 void nfs_fs_proc_net_exit(struct net *net)
1426 {
1427 	remove_proc_subtree("nfsfs", net->proc_net);
1428 }
1429 
1430 /*
1431  * initialise the /proc/fs/nfsfs/ directory
1432  */
1433 int __init nfs_fs_proc_init(void)
1434 {
1435 	if (!proc_mkdir("fs/nfsfs", NULL))
1436 		goto error_0;
1437 
1438 	/* a file of servers with which we're dealing */
1439 	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
1440 		goto error_1;
1441 
1442 	/* a file of volumes that we have mounted */
1443 	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
1444 		goto error_1;
1445 
1446 	return 0;
1447 error_1:
1448 	remove_proc_subtree("fs/nfsfs", NULL);
1449 error_0:
1450 	return -ENOMEM;
1451 }
1452 
1453 /*
1454  * clean up the /proc/fs/nfsfs/ directory
1455  */
1456 void nfs_fs_proc_exit(void)
1457 {
1458 	remove_proc_subtree("fs/nfsfs", NULL);
1459 	ida_destroy(&s_sysfs_ids);
1460 }
1461 
1462 #endif /* CONFIG_PROC_FS */
1463