xref: /linux/fs/nfs/client.c (revision 861e10be08c69808065d755d3e3cab5d520a2d32)
1 /* client.c: NFS client sharing and management code
2  *
3  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/sched.h>
16 #include <linux/time.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/string.h>
20 #include <linux/stat.h>
21 #include <linux/errno.h>
22 #include <linux/unistd.h>
23 #include <linux/sunrpc/clnt.h>
24 #include <linux/sunrpc/stats.h>
25 #include <linux/sunrpc/metrics.h>
26 #include <linux/sunrpc/xprtsock.h>
27 #include <linux/sunrpc/xprtrdma.h>
28 #include <linux/nfs_fs.h>
29 #include <linux/nfs_mount.h>
30 #include <linux/nfs4_mount.h>
31 #include <linux/lockd/bind.h>
32 #include <linux/seq_file.h>
33 #include <linux/mount.h>
34 #include <linux/nfs_idmap.h>
35 #include <linux/vfs.h>
36 #include <linux/inet.h>
37 #include <linux/in6.h>
38 #include <linux/slab.h>
39 #include <linux/idr.h>
40 #include <net/ipv6.h>
41 #include <linux/nfs_xdr.h>
42 #include <linux/sunrpc/bc_xprt.h>
43 #include <linux/nsproxy.h>
44 #include <linux/pid_namespace.h>
45 
46 
47 #include "nfs4_fs.h"
48 #include "callback.h"
49 #include "delegation.h"
50 #include "iostat.h"
51 #include "internal.h"
52 #include "fscache.h"
53 #include "pnfs.h"
54 #include "nfs.h"
55 #include "netns.h"
56 
57 #define NFSDBG_FACILITY		NFSDBG_CLIENT
58 
59 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
60 static DEFINE_SPINLOCK(nfs_version_lock);
61 static DEFINE_MUTEX(nfs_version_mutex);
62 static LIST_HEAD(nfs_versions);
63 
64 /*
65  * RPC cruft for NFS
66  */
67 static const struct rpc_version *nfs_version[5] = {
68 	[2] = NULL,
69 	[3] = NULL,
70 	[4] = NULL,
71 };
72 
73 const struct rpc_program nfs_program = {
74 	.name			= "nfs",
75 	.number			= NFS_PROGRAM,
76 	.nrvers			= ARRAY_SIZE(nfs_version),
77 	.version		= nfs_version,
78 	.stats			= &nfs_rpcstat,
79 	.pipe_dir_name		= NFS_PIPE_DIRNAME,
80 };
81 
82 struct rpc_stat nfs_rpcstat = {
83 	.program		= &nfs_program
84 };
85 
86 static struct nfs_subversion *find_nfs_version(unsigned int version)
87 {
88 	struct nfs_subversion *nfs;
89 	spin_lock(&nfs_version_lock);
90 
91 	list_for_each_entry(nfs, &nfs_versions, list) {
92 		if (nfs->rpc_ops->version == version) {
93 			spin_unlock(&nfs_version_lock);
94 			return nfs;
95 		}
96 	}
97 
98 	spin_unlock(&nfs_version_lock);
99 	return ERR_PTR(-EPROTONOSUPPORT);
100 }
101 
102 struct nfs_subversion *get_nfs_version(unsigned int version)
103 {
104 	struct nfs_subversion *nfs = find_nfs_version(version);
105 
106 	if (IS_ERR(nfs)) {
107 		mutex_lock(&nfs_version_mutex);
108 		request_module("nfsv%d", version);
109 		nfs = find_nfs_version(version);
110 		mutex_unlock(&nfs_version_mutex);
111 	}
112 
113 	if (!IS_ERR(nfs))
114 		try_module_get(nfs->owner);
115 	return nfs;
116 }
117 
118 void put_nfs_version(struct nfs_subversion *nfs)
119 {
120 	module_put(nfs->owner);
121 }
122 
123 void register_nfs_version(struct nfs_subversion *nfs)
124 {
125 	spin_lock(&nfs_version_lock);
126 
127 	list_add(&nfs->list, &nfs_versions);
128 	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
129 
130 	spin_unlock(&nfs_version_lock);
131 }
132 EXPORT_SYMBOL_GPL(register_nfs_version);
133 
134 void unregister_nfs_version(struct nfs_subversion *nfs)
135 {
136 	spin_lock(&nfs_version_lock);
137 
138 	nfs_version[nfs->rpc_ops->version] = NULL;
139 	list_del(&nfs->list);
140 
141 	spin_unlock(&nfs_version_lock);
142 }
143 EXPORT_SYMBOL_GPL(unregister_nfs_version);
144 
145 /*
146  * Allocate a shared client record
147  *
148  * Since these are allocated/deallocated very rarely, we don't
149  * bother putting them in a slab cache...
150  */
151 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
152 {
153 	struct nfs_client *clp;
154 	struct rpc_cred *cred;
155 	int err = -ENOMEM;
156 
157 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
158 		goto error_0;
159 
160 	clp->cl_nfs_mod = cl_init->nfs_mod;
161 	try_module_get(clp->cl_nfs_mod->owner);
162 
163 	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
164 
165 	atomic_set(&clp->cl_count, 1);
166 	clp->cl_cons_state = NFS_CS_INITING;
167 
168 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
169 	clp->cl_addrlen = cl_init->addrlen;
170 
171 	if (cl_init->hostname) {
172 		err = -ENOMEM;
173 		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
174 		if (!clp->cl_hostname)
175 			goto error_cleanup;
176 	}
177 
178 	INIT_LIST_HEAD(&clp->cl_superblocks);
179 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
180 
181 	clp->cl_proto = cl_init->proto;
182 	clp->cl_net = get_net(cl_init->net);
183 
184 	cred = rpc_lookup_machine_cred("*");
185 	if (!IS_ERR(cred))
186 		clp->cl_machine_cred = cred;
187 	nfs_fscache_get_client_cookie(clp);
188 
189 	return clp;
190 
191 error_cleanup:
192 	put_nfs_version(clp->cl_nfs_mod);
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 /* idr_remove_all is not needed as all id's are removed by nfs_put_client */
201 void nfs_cleanup_cb_ident_idr(struct net *net)
202 {
203 	struct nfs_net *nn = net_generic(net, nfs_net_id);
204 
205 	idr_destroy(&nn->cb_ident_idr);
206 }
207 
208 /* nfs_client_lock held */
209 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
210 {
211 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
212 
213 	if (clp->cl_cb_ident)
214 		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
215 }
216 
217 static void pnfs_init_server(struct nfs_server *server)
218 {
219 	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
220 }
221 
222 #else
223 void nfs_cleanup_cb_ident_idr(struct net *net)
224 {
225 }
226 
227 static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
228 {
229 }
230 
231 static void pnfs_init_server(struct nfs_server *server)
232 {
233 }
234 
235 #endif /* CONFIG_NFS_V4 */
236 
237 /*
238  * Destroy a shared client record
239  */
240 void nfs_free_client(struct nfs_client *clp)
241 {
242 	dprintk("--> nfs_free_client(%u)\n", clp->rpc_ops->version);
243 
244 	nfs_fscache_release_client_cookie(clp);
245 
246 	/* -EIO all pending I/O */
247 	if (!IS_ERR(clp->cl_rpcclient))
248 		rpc_shutdown_client(clp->cl_rpcclient);
249 
250 	if (clp->cl_machine_cred != NULL)
251 		put_rpccred(clp->cl_machine_cred);
252 
253 	put_net(clp->cl_net);
254 	put_nfs_version(clp->cl_nfs_mod);
255 	kfree(clp->cl_hostname);
256 	kfree(clp);
257 
258 	dprintk("<-- nfs_free_client()\n");
259 }
260 EXPORT_SYMBOL_GPL(nfs_free_client);
261 
262 /*
263  * Release a reference to a shared client record
264  */
265 void nfs_put_client(struct nfs_client *clp)
266 {
267 	struct nfs_net *nn;
268 
269 	if (!clp)
270 		return;
271 
272 	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
273 	nn = net_generic(clp->cl_net, nfs_net_id);
274 
275 	if (atomic_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
276 		list_del(&clp->cl_share_link);
277 		nfs_cb_idr_remove_locked(clp);
278 		spin_unlock(&nn->nfs_client_lock);
279 
280 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
281 
282 		clp->rpc_ops->free_client(clp);
283 	}
284 }
285 EXPORT_SYMBOL_GPL(nfs_put_client);
286 
287 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
288 /*
289  * Test if two ip6 socket addresses refer to the same socket by
290  * comparing relevant fields. The padding bytes specifically, are not
291  * compared. sin6_flowinfo is not compared because it only affects QoS
292  * and sin6_scope_id is only compared if the address is "link local"
293  * because "link local" addresses need only be unique to a specific
294  * link. Conversely, ordinary unicast addresses might have different
295  * sin6_scope_id.
296  *
297  * The caller should ensure both socket addresses are AF_INET6.
298  */
299 static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
300 				      const struct sockaddr *sa2)
301 {
302 	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
303 	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
304 
305 	if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
306 		return 0;
307 	else if (ipv6_addr_type(&sin1->sin6_addr) & IPV6_ADDR_LINKLOCAL)
308 		return sin1->sin6_scope_id == sin2->sin6_scope_id;
309 
310 	return 1;
311 }
312 #else	/* !defined(CONFIG_IPV6) && !defined(CONFIG_IPV6_MODULE) */
313 static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
314 				      const struct sockaddr *sa2)
315 {
316 	return 0;
317 }
318 #endif
319 
320 /*
321  * Test if two ip4 socket addresses refer to the same socket, by
322  * comparing relevant fields. The padding bytes specifically, are
323  * not compared.
324  *
325  * The caller should ensure both socket addresses are AF_INET.
326  */
327 static int nfs_sockaddr_match_ipaddr4(const struct sockaddr *sa1,
328 				      const struct sockaddr *sa2)
329 {
330 	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
331 	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
332 
333 	return sin1->sin_addr.s_addr == sin2->sin_addr.s_addr;
334 }
335 
336 static int nfs_sockaddr_cmp_ip6(const struct sockaddr *sa1,
337 				const struct sockaddr *sa2)
338 {
339 	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
340 	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
341 
342 	return nfs_sockaddr_match_ipaddr6(sa1, sa2) &&
343 		(sin1->sin6_port == sin2->sin6_port);
344 }
345 
346 static int nfs_sockaddr_cmp_ip4(const struct sockaddr *sa1,
347 				const struct sockaddr *sa2)
348 {
349 	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
350 	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
351 
352 	return nfs_sockaddr_match_ipaddr4(sa1, sa2) &&
353 		(sin1->sin_port == sin2->sin_port);
354 }
355 
356 #if defined(CONFIG_NFS_V4_1)
357 /*
358  * Test if two socket addresses represent the same actual socket,
359  * by comparing (only) relevant fields, excluding the port number.
360  */
361 int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
362 			      const struct sockaddr *sa2)
363 {
364 	if (sa1->sa_family != sa2->sa_family)
365 		return 0;
366 
367 	switch (sa1->sa_family) {
368 	case AF_INET:
369 		return nfs_sockaddr_match_ipaddr4(sa1, sa2);
370 	case AF_INET6:
371 		return nfs_sockaddr_match_ipaddr6(sa1, sa2);
372 	}
373 	return 0;
374 }
375 EXPORT_SYMBOL_GPL(nfs_sockaddr_match_ipaddr);
376 #endif /* CONFIG_NFS_V4_1 */
377 
378 /*
379  * Test if two socket addresses represent the same actual socket,
380  * by comparing (only) relevant fields, including the port number.
381  */
382 static int nfs_sockaddr_cmp(const struct sockaddr *sa1,
383 			    const struct sockaddr *sa2)
384 {
385 	if (sa1->sa_family != sa2->sa_family)
386 		return 0;
387 
388 	switch (sa1->sa_family) {
389 	case AF_INET:
390 		return nfs_sockaddr_cmp_ip4(sa1, sa2);
391 	case AF_INET6:
392 		return nfs_sockaddr_cmp_ip6(sa1, sa2);
393 	}
394 	return 0;
395 }
396 
397 /*
398  * Find an nfs_client on the list that matches the initialisation data
399  * that is supplied.
400  */
401 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
402 {
403 	struct nfs_client *clp;
404 	const struct sockaddr *sap = data->addr;
405 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
406 
407 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
408 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
409 		/* Don't match clients that failed to initialise properly */
410 		if (clp->cl_cons_state < 0)
411 			continue;
412 
413 		/* Different NFS versions cannot share the same nfs_client */
414 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
415 			continue;
416 
417 		if (clp->cl_proto != data->proto)
418 			continue;
419 		/* Match nfsv4 minorversion */
420 		if (clp->cl_minorversion != data->minorversion)
421 			continue;
422 		/* Match the full socket address */
423 		if (!nfs_sockaddr_cmp(sap, clap))
424 			continue;
425 
426 		atomic_inc(&clp->cl_count);
427 		return clp;
428 	}
429 	return NULL;
430 }
431 
432 static bool nfs_client_init_is_complete(const struct nfs_client *clp)
433 {
434 	return clp->cl_cons_state != NFS_CS_INITING;
435 }
436 
437 int nfs_wait_client_init_complete(const struct nfs_client *clp)
438 {
439 	return wait_event_killable(nfs_client_active_wq,
440 			nfs_client_init_is_complete(clp));
441 }
442 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
443 
444 /*
445  * Found an existing client.  Make sure it's ready before returning.
446  */
447 static struct nfs_client *
448 nfs_found_client(const struct nfs_client_initdata *cl_init,
449 		 struct nfs_client *clp)
450 {
451 	int error;
452 
453 	error = nfs_wait_client_init_complete(clp);
454 	if (error < 0) {
455 		nfs_put_client(clp);
456 		return ERR_PTR(-ERESTARTSYS);
457 	}
458 
459 	if (clp->cl_cons_state < NFS_CS_READY) {
460 		error = clp->cl_cons_state;
461 		nfs_put_client(clp);
462 		return ERR_PTR(error);
463 	}
464 
465 	smp_rmb();
466 
467 	dprintk("<-- %s found nfs_client %p for %s\n",
468 		__func__, clp, cl_init->hostname ?: "");
469 	return clp;
470 }
471 
472 /*
473  * Look up a client by IP address and protocol version
474  * - creates a new record if one doesn't yet exist
475  */
476 struct nfs_client *
477 nfs_get_client(const struct nfs_client_initdata *cl_init,
478 	       const struct rpc_timeout *timeparms,
479 	       const char *ip_addr,
480 	       rpc_authflavor_t authflavour)
481 {
482 	struct nfs_client *clp, *new = NULL;
483 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
484 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
485 
486 	dprintk("--> nfs_get_client(%s,v%u)\n",
487 		cl_init->hostname ?: "", rpc_ops->version);
488 
489 	/* see if the client already exists */
490 	do {
491 		spin_lock(&nn->nfs_client_lock);
492 
493 		clp = nfs_match_client(cl_init);
494 		if (clp) {
495 			spin_unlock(&nn->nfs_client_lock);
496 			if (new)
497 				new->rpc_ops->free_client(new);
498 			return nfs_found_client(cl_init, clp);
499 		}
500 		if (new) {
501 			list_add_tail(&new->cl_share_link,
502 					&nn->nfs_client_list);
503 			spin_unlock(&nn->nfs_client_lock);
504 			new->cl_flags = cl_init->init_flags;
505 			return rpc_ops->init_client(new, timeparms, ip_addr,
506 						    authflavour);
507 		}
508 
509 		spin_unlock(&nn->nfs_client_lock);
510 
511 		new = rpc_ops->alloc_client(cl_init);
512 	} while (!IS_ERR(new));
513 
514 	dprintk("<-- nfs_get_client() Failed to find %s (%ld)\n",
515 		cl_init->hostname ?: "", PTR_ERR(new));
516 	return new;
517 }
518 EXPORT_SYMBOL_GPL(nfs_get_client);
519 
520 /*
521  * Mark a server as ready or failed
522  */
523 void nfs_mark_client_ready(struct nfs_client *clp, int state)
524 {
525 	smp_wmb();
526 	clp->cl_cons_state = state;
527 	wake_up_all(&nfs_client_active_wq);
528 }
529 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
530 
531 /*
532  * Initialise the timeout values for a connection
533  */
534 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
535 				    unsigned int timeo, unsigned int retrans)
536 {
537 	to->to_initval = timeo * HZ / 10;
538 	to->to_retries = retrans;
539 
540 	switch (proto) {
541 	case XPRT_TRANSPORT_TCP:
542 	case XPRT_TRANSPORT_RDMA:
543 		if (to->to_retries == 0)
544 			to->to_retries = NFS_DEF_TCP_RETRANS;
545 		if (to->to_initval == 0)
546 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
547 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
548 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
549 		to->to_increment = to->to_initval;
550 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
551 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
552 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
553 		if (to->to_maxval < to->to_initval)
554 			to->to_maxval = to->to_initval;
555 		to->to_exponential = 0;
556 		break;
557 	case XPRT_TRANSPORT_UDP:
558 		if (to->to_retries == 0)
559 			to->to_retries = NFS_DEF_UDP_RETRANS;
560 		if (!to->to_initval)
561 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
562 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
563 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
564 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
565 		to->to_exponential = 1;
566 		break;
567 	default:
568 		BUG();
569 	}
570 }
571 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
572 
573 /*
574  * Create an RPC client handle
575  */
576 int nfs_create_rpc_client(struct nfs_client *clp,
577 			  const struct rpc_timeout *timeparms,
578 			  rpc_authflavor_t flavor)
579 {
580 	struct rpc_clnt		*clnt = NULL;
581 	struct rpc_create_args args = {
582 		.net		= clp->cl_net,
583 		.protocol	= clp->cl_proto,
584 		.address	= (struct sockaddr *)&clp->cl_addr,
585 		.addrsize	= clp->cl_addrlen,
586 		.timeout	= timeparms,
587 		.servername	= clp->cl_hostname,
588 		.program	= &nfs_program,
589 		.version	= clp->rpc_ops->version,
590 		.authflavor	= flavor,
591 	};
592 
593 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
594 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
595 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
596 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
597 
598 	if (!IS_ERR(clp->cl_rpcclient))
599 		return 0;
600 
601 	clnt = rpc_create(&args);
602 	if (IS_ERR(clnt)) {
603 		dprintk("%s: cannot create RPC client. Error = %ld\n",
604 				__func__, PTR_ERR(clnt));
605 		return PTR_ERR(clnt);
606 	}
607 
608 	clp->cl_rpcclient = clnt;
609 	return 0;
610 }
611 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
612 
613 /*
614  * Version 2 or 3 client destruction
615  */
616 static void nfs_destroy_server(struct nfs_server *server)
617 {
618 	if (server->nlm_host)
619 		nlmclnt_done(server->nlm_host);
620 }
621 
622 /*
623  * Version 2 or 3 lockd setup
624  */
625 static int nfs_start_lockd(struct nfs_server *server)
626 {
627 	struct nlm_host *host;
628 	struct nfs_client *clp = server->nfs_client;
629 	struct nlmclnt_initdata nlm_init = {
630 		.hostname	= clp->cl_hostname,
631 		.address	= (struct sockaddr *)&clp->cl_addr,
632 		.addrlen	= clp->cl_addrlen,
633 		.nfs_version	= clp->rpc_ops->version,
634 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
635 					1 : 0,
636 		.net		= clp->cl_net,
637 	};
638 
639 	if (nlm_init.nfs_version > 3)
640 		return 0;
641 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
642 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
643 		return 0;
644 
645 	switch (clp->cl_proto) {
646 		default:
647 			nlm_init.protocol = IPPROTO_TCP;
648 			break;
649 		case XPRT_TRANSPORT_UDP:
650 			nlm_init.protocol = IPPROTO_UDP;
651 	}
652 
653 	host = nlmclnt_init(&nlm_init);
654 	if (IS_ERR(host))
655 		return PTR_ERR(host);
656 
657 	server->nlm_host = host;
658 	server->destroy = nfs_destroy_server;
659 	return 0;
660 }
661 
662 /*
663  * Create a general RPC client
664  */
665 int nfs_init_server_rpcclient(struct nfs_server *server,
666 		const struct rpc_timeout *timeo,
667 		rpc_authflavor_t pseudoflavour)
668 {
669 	struct nfs_client *clp = server->nfs_client;
670 
671 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
672 							pseudoflavour);
673 	if (IS_ERR(server->client)) {
674 		dprintk("%s: couldn't create rpc_client!\n", __func__);
675 		return PTR_ERR(server->client);
676 	}
677 
678 	memcpy(&server->client->cl_timeout_default,
679 			timeo,
680 			sizeof(server->client->cl_timeout_default));
681 	server->client->cl_timeout = &server->client->cl_timeout_default;
682 	server->client->cl_softrtry = 0;
683 	if (server->flags & NFS_MOUNT_SOFT)
684 		server->client->cl_softrtry = 1;
685 
686 	return 0;
687 }
688 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
689 
690 /**
691  * nfs_init_client - Initialise an NFS2 or NFS3 client
692  *
693  * @clp: nfs_client to initialise
694  * @timeparms: timeout parameters for underlying RPC transport
695  * @ip_addr: IP presentation address (not used)
696  * @authflavor: authentication flavor for underlying RPC transport
697  *
698  * Returns pointer to an NFS client, or an ERR_PTR value.
699  */
700 struct nfs_client *nfs_init_client(struct nfs_client *clp,
701 		    const struct rpc_timeout *timeparms,
702 		    const char *ip_addr, rpc_authflavor_t authflavour)
703 {
704 	int error;
705 
706 	if (clp->cl_cons_state == NFS_CS_READY) {
707 		/* the client is already initialised */
708 		dprintk("<-- nfs_init_client() = 0 [already %p]\n", clp);
709 		return clp;
710 	}
711 
712 	/*
713 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
714 	 * - RFC 2623, sec 2.3.2
715 	 */
716 	error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_UNIX);
717 	if (error < 0)
718 		goto error;
719 	nfs_mark_client_ready(clp, NFS_CS_READY);
720 	return clp;
721 
722 error:
723 	nfs_mark_client_ready(clp, error);
724 	nfs_put_client(clp);
725 	dprintk("<-- nfs_init_client() = xerror %d\n", error);
726 	return ERR_PTR(error);
727 }
728 EXPORT_SYMBOL_GPL(nfs_init_client);
729 
730 /*
731  * Create a version 2 or 3 client
732  */
733 static int nfs_init_server(struct nfs_server *server,
734 			   const struct nfs_parsed_mount_data *data,
735 			   struct nfs_subversion *nfs_mod)
736 {
737 	struct nfs_client_initdata cl_init = {
738 		.hostname = data->nfs_server.hostname,
739 		.addr = (const struct sockaddr *)&data->nfs_server.address,
740 		.addrlen = data->nfs_server.addrlen,
741 		.nfs_mod = nfs_mod,
742 		.proto = data->nfs_server.protocol,
743 		.net = data->net,
744 	};
745 	struct rpc_timeout timeparms;
746 	struct nfs_client *clp;
747 	int error;
748 
749 	dprintk("--> nfs_init_server()\n");
750 
751 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
752 			data->timeo, data->retrans);
753 	if (data->flags & NFS_MOUNT_NORESVPORT)
754 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
755 	if (server->options & NFS_OPTION_MIGRATION)
756 		set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
757 
758 	/* Allocate or find a client reference we can use */
759 	clp = nfs_get_client(&cl_init, &timeparms, NULL, RPC_AUTH_UNIX);
760 	if (IS_ERR(clp)) {
761 		dprintk("<-- nfs_init_server() = error %ld\n", PTR_ERR(clp));
762 		return PTR_ERR(clp);
763 	}
764 
765 	server->nfs_client = clp;
766 
767 	/* Initialise the client representation from the mount data */
768 	server->flags = data->flags;
769 	server->options = data->options;
770 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
771 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
772 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME|NFS_CAP_CHANGE_ATTR;
773 
774 	if (data->rsize)
775 		server->rsize = nfs_block_size(data->rsize, NULL);
776 	if (data->wsize)
777 		server->wsize = nfs_block_size(data->wsize, NULL);
778 
779 	server->acregmin = data->acregmin * HZ;
780 	server->acregmax = data->acregmax * HZ;
781 	server->acdirmin = data->acdirmin * HZ;
782 	server->acdirmax = data->acdirmax * HZ;
783 
784 	/* Start lockd here, before we might error out */
785 	error = nfs_start_lockd(server);
786 	if (error < 0)
787 		goto error;
788 
789 	server->port = data->nfs_server.port;
790 
791 	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
792 	if (error < 0)
793 		goto error;
794 
795 	/* Preserve the values of mount_server-related mount options */
796 	if (data->mount_server.addrlen) {
797 		memcpy(&server->mountd_address, &data->mount_server.address,
798 			data->mount_server.addrlen);
799 		server->mountd_addrlen = data->mount_server.addrlen;
800 	}
801 	server->mountd_version = data->mount_server.version;
802 	server->mountd_port = data->mount_server.port;
803 	server->mountd_protocol = data->mount_server.protocol;
804 
805 	server->namelen  = data->namlen;
806 	dprintk("<-- nfs_init_server() = 0 [new %p]\n", clp);
807 	return 0;
808 
809 error:
810 	server->nfs_client = NULL;
811 	nfs_put_client(clp);
812 	dprintk("<-- nfs_init_server() = xerror %d\n", error);
813 	return error;
814 }
815 
816 /*
817  * Load up the server record from information gained in an fsinfo record
818  */
819 static void nfs_server_set_fsinfo(struct nfs_server *server,
820 				  struct nfs_fh *mntfh,
821 				  struct nfs_fsinfo *fsinfo)
822 {
823 	unsigned long max_rpc_payload;
824 
825 	/* Work out a lot of parameters */
826 	if (server->rsize == 0)
827 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
828 	if (server->wsize == 0)
829 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
830 
831 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
832 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
833 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
834 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
835 
836 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
837 	if (server->rsize > max_rpc_payload)
838 		server->rsize = max_rpc_payload;
839 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
840 		server->rsize = NFS_MAX_FILE_IO_SIZE;
841 	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
842 
843 	server->backing_dev_info.name = "nfs";
844 	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
845 
846 	if (server->wsize > max_rpc_payload)
847 		server->wsize = max_rpc_payload;
848 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
849 		server->wsize = NFS_MAX_FILE_IO_SIZE;
850 	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
851 
852 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
853 
854 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
855 	if (server->dtsize > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES)
856 		server->dtsize = PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES;
857 	if (server->dtsize > server->rsize)
858 		server->dtsize = server->rsize;
859 
860 	if (server->flags & NFS_MOUNT_NOAC) {
861 		server->acregmin = server->acregmax = 0;
862 		server->acdirmin = server->acdirmax = 0;
863 	}
864 
865 	server->maxfilesize = fsinfo->maxfilesize;
866 
867 	server->time_delta = fsinfo->time_delta;
868 
869 	/* We're airborne Set socket buffersize */
870 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
871 }
872 
873 /*
874  * Probe filesystem information, including the FSID on v2/v3
875  */
876 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
877 {
878 	struct nfs_fsinfo fsinfo;
879 	struct nfs_client *clp = server->nfs_client;
880 	int error;
881 
882 	dprintk("--> nfs_probe_fsinfo()\n");
883 
884 	if (clp->rpc_ops->set_capabilities != NULL) {
885 		error = clp->rpc_ops->set_capabilities(server, mntfh);
886 		if (error < 0)
887 			goto out_error;
888 	}
889 
890 	fsinfo.fattr = fattr;
891 	fsinfo.layouttype = 0;
892 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
893 	if (error < 0)
894 		goto out_error;
895 
896 	nfs_server_set_fsinfo(server, mntfh, &fsinfo);
897 
898 	/* Get some general file system info */
899 	if (server->namelen == 0) {
900 		struct nfs_pathconf pathinfo;
901 
902 		pathinfo.fattr = fattr;
903 		nfs_fattr_init(fattr);
904 
905 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
906 			server->namelen = pathinfo.max_namelen;
907 	}
908 
909 	dprintk("<-- nfs_probe_fsinfo() = 0\n");
910 	return 0;
911 
912 out_error:
913 	dprintk("nfs_probe_fsinfo: error = %d\n", -error);
914 	return error;
915 }
916 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
917 
918 /*
919  * Copy useful information when duplicating a server record
920  */
921 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
922 {
923 	target->flags = source->flags;
924 	target->rsize = source->rsize;
925 	target->wsize = source->wsize;
926 	target->acregmin = source->acregmin;
927 	target->acregmax = source->acregmax;
928 	target->acdirmin = source->acdirmin;
929 	target->acdirmax = source->acdirmax;
930 	target->caps = source->caps;
931 	target->options = source->options;
932 }
933 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
934 
935 void nfs_server_insert_lists(struct nfs_server *server)
936 {
937 	struct nfs_client *clp = server->nfs_client;
938 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
939 
940 	spin_lock(&nn->nfs_client_lock);
941 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
942 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
943 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
944 	spin_unlock(&nn->nfs_client_lock);
945 
946 }
947 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
948 
949 static void nfs_server_remove_lists(struct nfs_server *server)
950 {
951 	struct nfs_client *clp = server->nfs_client;
952 	struct nfs_net *nn;
953 
954 	if (clp == NULL)
955 		return;
956 	nn = net_generic(clp->cl_net, nfs_net_id);
957 	spin_lock(&nn->nfs_client_lock);
958 	list_del_rcu(&server->client_link);
959 	if (list_empty(&clp->cl_superblocks))
960 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
961 	list_del(&server->master_link);
962 	spin_unlock(&nn->nfs_client_lock);
963 
964 	synchronize_rcu();
965 }
966 
967 /*
968  * Allocate and initialise a server record
969  */
970 struct nfs_server *nfs_alloc_server(void)
971 {
972 	struct nfs_server *server;
973 
974 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
975 	if (!server)
976 		return NULL;
977 
978 	server->client = server->client_acl = ERR_PTR(-EINVAL);
979 
980 	/* Zero out the NFS state stuff */
981 	INIT_LIST_HEAD(&server->client_link);
982 	INIT_LIST_HEAD(&server->master_link);
983 	INIT_LIST_HEAD(&server->delegations);
984 	INIT_LIST_HEAD(&server->layouts);
985 	INIT_LIST_HEAD(&server->state_owners_lru);
986 
987 	atomic_set(&server->active, 0);
988 
989 	server->io_stats = nfs_alloc_iostats();
990 	if (!server->io_stats) {
991 		kfree(server);
992 		return NULL;
993 	}
994 
995 	if (bdi_init(&server->backing_dev_info)) {
996 		nfs_free_iostats(server->io_stats);
997 		kfree(server);
998 		return NULL;
999 	}
1000 
1001 	ida_init(&server->openowner_id);
1002 	ida_init(&server->lockowner_id);
1003 	pnfs_init_server(server);
1004 
1005 	return server;
1006 }
1007 EXPORT_SYMBOL_GPL(nfs_alloc_server);
1008 
1009 /*
1010  * Free up a server record
1011  */
1012 void nfs_free_server(struct nfs_server *server)
1013 {
1014 	dprintk("--> nfs_free_server()\n");
1015 
1016 	nfs_server_remove_lists(server);
1017 
1018 	if (server->destroy != NULL)
1019 		server->destroy(server);
1020 
1021 	if (!IS_ERR(server->client_acl))
1022 		rpc_shutdown_client(server->client_acl);
1023 	if (!IS_ERR(server->client))
1024 		rpc_shutdown_client(server->client);
1025 
1026 	nfs_put_client(server->nfs_client);
1027 
1028 	ida_destroy(&server->lockowner_id);
1029 	ida_destroy(&server->openowner_id);
1030 	nfs_free_iostats(server->io_stats);
1031 	bdi_destroy(&server->backing_dev_info);
1032 	kfree(server);
1033 	nfs_release_automount_timer();
1034 	dprintk("<-- nfs_free_server()\n");
1035 }
1036 EXPORT_SYMBOL_GPL(nfs_free_server);
1037 
1038 /*
1039  * Create a version 2 or 3 volume record
1040  * - keyed on server and FSID
1041  */
1042 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
1043 				     struct nfs_subversion *nfs_mod)
1044 {
1045 	struct nfs_server *server;
1046 	struct nfs_fattr *fattr;
1047 	int error;
1048 
1049 	server = nfs_alloc_server();
1050 	if (!server)
1051 		return ERR_PTR(-ENOMEM);
1052 
1053 	error = -ENOMEM;
1054 	fattr = nfs_alloc_fattr();
1055 	if (fattr == NULL)
1056 		goto error;
1057 
1058 	/* Get a client representation */
1059 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
1060 	if (error < 0)
1061 		goto error;
1062 
1063 	/* Probe the root fh to retrieve its FSID */
1064 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
1065 	if (error < 0)
1066 		goto error;
1067 	if (server->nfs_client->rpc_ops->version == 3) {
1068 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
1069 			server->namelen = NFS3_MAXNAMLEN;
1070 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
1071 			server->caps |= NFS_CAP_READDIRPLUS;
1072 	} else {
1073 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
1074 			server->namelen = NFS2_MAXNAMLEN;
1075 	}
1076 
1077 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
1078 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh, fattr);
1079 		if (error < 0) {
1080 			dprintk("nfs_create_server: getattr error = %d\n", -error);
1081 			goto error;
1082 		}
1083 	}
1084 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
1085 
1086 	dprintk("Server FSID: %llx:%llx\n",
1087 		(unsigned long long) server->fsid.major,
1088 		(unsigned long long) server->fsid.minor);
1089 
1090 	nfs_server_insert_lists(server);
1091 	server->mount_time = jiffies;
1092 	nfs_free_fattr(fattr);
1093 	return server;
1094 
1095 error:
1096 	nfs_free_fattr(fattr);
1097 	nfs_free_server(server);
1098 	return ERR_PTR(error);
1099 }
1100 EXPORT_SYMBOL_GPL(nfs_create_server);
1101 
1102 /*
1103  * Clone an NFS2, NFS3 or NFS4 server record
1104  */
1105 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1106 				    struct nfs_fh *fh,
1107 				    struct nfs_fattr *fattr,
1108 				    rpc_authflavor_t flavor)
1109 {
1110 	struct nfs_server *server;
1111 	struct nfs_fattr *fattr_fsinfo;
1112 	int error;
1113 
1114 	dprintk("--> nfs_clone_server(,%llx:%llx,)\n",
1115 		(unsigned long long) fattr->fsid.major,
1116 		(unsigned long long) fattr->fsid.minor);
1117 
1118 	server = nfs_alloc_server();
1119 	if (!server)
1120 		return ERR_PTR(-ENOMEM);
1121 
1122 	error = -ENOMEM;
1123 	fattr_fsinfo = nfs_alloc_fattr();
1124 	if (fattr_fsinfo == NULL)
1125 		goto out_free_server;
1126 
1127 	/* Copy data from the source */
1128 	server->nfs_client = source->nfs_client;
1129 	server->destroy = source->destroy;
1130 	atomic_inc(&server->nfs_client->cl_count);
1131 	nfs_server_copy_userdata(server, source);
1132 
1133 	server->fsid = fattr->fsid;
1134 
1135 	error = nfs_init_server_rpcclient(server,
1136 			source->client->cl_timeout,
1137 			flavor);
1138 	if (error < 0)
1139 		goto out_free_server;
1140 
1141 	/* probe the filesystem info for this server filesystem */
1142 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1143 	if (error < 0)
1144 		goto out_free_server;
1145 
1146 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1147 		server->namelen = NFS4_MAXNAMLEN;
1148 
1149 	dprintk("Cloned FSID: %llx:%llx\n",
1150 		(unsigned long long) server->fsid.major,
1151 		(unsigned long long) server->fsid.minor);
1152 
1153 	error = nfs_start_lockd(server);
1154 	if (error < 0)
1155 		goto out_free_server;
1156 
1157 	nfs_server_insert_lists(server);
1158 	server->mount_time = jiffies;
1159 
1160 	nfs_free_fattr(fattr_fsinfo);
1161 	dprintk("<-- nfs_clone_server() = %p\n", server);
1162 	return server;
1163 
1164 out_free_server:
1165 	nfs_free_fattr(fattr_fsinfo);
1166 	nfs_free_server(server);
1167 	dprintk("<-- nfs_clone_server() = error %d\n", error);
1168 	return ERR_PTR(error);
1169 }
1170 EXPORT_SYMBOL_GPL(nfs_clone_server);
1171 
1172 void nfs_clients_init(struct net *net)
1173 {
1174 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1175 
1176 	INIT_LIST_HEAD(&nn->nfs_client_list);
1177 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1178 #if IS_ENABLED(CONFIG_NFS_V4)
1179 	idr_init(&nn->cb_ident_idr);
1180 #endif
1181 	spin_lock_init(&nn->nfs_client_lock);
1182 	nn->boot_time = CURRENT_TIME;
1183 }
1184 
1185 #ifdef CONFIG_PROC_FS
1186 static struct proc_dir_entry *proc_fs_nfs;
1187 
1188 static int nfs_server_list_open(struct inode *inode, struct file *file);
1189 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1190 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1191 static void nfs_server_list_stop(struct seq_file *p, void *v);
1192 static int nfs_server_list_show(struct seq_file *m, void *v);
1193 
1194 static const struct seq_operations nfs_server_list_ops = {
1195 	.start	= nfs_server_list_start,
1196 	.next	= nfs_server_list_next,
1197 	.stop	= nfs_server_list_stop,
1198 	.show	= nfs_server_list_show,
1199 };
1200 
1201 static const struct file_operations nfs_server_list_fops = {
1202 	.open		= nfs_server_list_open,
1203 	.read		= seq_read,
1204 	.llseek		= seq_lseek,
1205 	.release	= seq_release,
1206 	.owner		= THIS_MODULE,
1207 };
1208 
1209 static int nfs_volume_list_open(struct inode *inode, struct file *file);
1210 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1211 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1212 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1213 static int nfs_volume_list_show(struct seq_file *m, void *v);
1214 
1215 static const struct seq_operations nfs_volume_list_ops = {
1216 	.start	= nfs_volume_list_start,
1217 	.next	= nfs_volume_list_next,
1218 	.stop	= nfs_volume_list_stop,
1219 	.show	= nfs_volume_list_show,
1220 };
1221 
1222 static const struct file_operations nfs_volume_list_fops = {
1223 	.open		= nfs_volume_list_open,
1224 	.read		= seq_read,
1225 	.llseek		= seq_lseek,
1226 	.release	= seq_release,
1227 	.owner		= THIS_MODULE,
1228 };
1229 
1230 /*
1231  * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
1232  * we're dealing
1233  */
1234 static int nfs_server_list_open(struct inode *inode, struct file *file)
1235 {
1236 	struct seq_file *m;
1237 	int ret;
1238 	struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
1239 	struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
1240 
1241 	ret = seq_open(file, &nfs_server_list_ops);
1242 	if (ret < 0)
1243 		return ret;
1244 
1245 	m = file->private_data;
1246 	m->private = net;
1247 
1248 	return 0;
1249 }
1250 
1251 /*
1252  * set up the iterator to start reading from the server list and return the first item
1253  */
1254 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1255 {
1256 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1257 
1258 	/* lock the list against modification */
1259 	spin_lock(&nn->nfs_client_lock);
1260 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1261 }
1262 
1263 /*
1264  * move to next server
1265  */
1266 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1267 {
1268 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1269 
1270 	return seq_list_next(v, &nn->nfs_client_list, pos);
1271 }
1272 
1273 /*
1274  * clean up after reading from the transports list
1275  */
1276 static void nfs_server_list_stop(struct seq_file *p, void *v)
1277 {
1278 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1279 
1280 	spin_unlock(&nn->nfs_client_lock);
1281 }
1282 
1283 /*
1284  * display a header line followed by a load of call lines
1285  */
1286 static int nfs_server_list_show(struct seq_file *m, void *v)
1287 {
1288 	struct nfs_client *clp;
1289 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1290 
1291 	/* display header on line 1 */
1292 	if (v == &nn->nfs_client_list) {
1293 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1294 		return 0;
1295 	}
1296 
1297 	/* display one transport per line on subsequent lines */
1298 	clp = list_entry(v, struct nfs_client, cl_share_link);
1299 
1300 	/* Check if the client is initialized */
1301 	if (clp->cl_cons_state != NFS_CS_READY)
1302 		return 0;
1303 
1304 	rcu_read_lock();
1305 	seq_printf(m, "v%u %s %s %3d %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 		   atomic_read(&clp->cl_count),
1310 		   clp->cl_hostname);
1311 	rcu_read_unlock();
1312 
1313 	return 0;
1314 }
1315 
1316 /*
1317  * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
1318  */
1319 static int nfs_volume_list_open(struct inode *inode, struct file *file)
1320 {
1321 	struct seq_file *m;
1322 	int ret;
1323 	struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
1324 	struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
1325 
1326 	ret = seq_open(file, &nfs_volume_list_ops);
1327 	if (ret < 0)
1328 		return ret;
1329 
1330 	m = file->private_data;
1331 	m->private = net;
1332 
1333 	return 0;
1334 }
1335 
1336 /*
1337  * set up the iterator to start reading from the volume list and return the first item
1338  */
1339 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1340 {
1341 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1342 
1343 	/* lock the list against modification */
1344 	spin_lock(&nn->nfs_client_lock);
1345 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1346 }
1347 
1348 /*
1349  * move to next volume
1350  */
1351 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1352 {
1353 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1354 
1355 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1356 }
1357 
1358 /*
1359  * clean up after reading from the transports list
1360  */
1361 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1362 {
1363 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1364 
1365 	spin_unlock(&nn->nfs_client_lock);
1366 }
1367 
1368 /*
1369  * display a header line followed by a load of call lines
1370  */
1371 static int nfs_volume_list_show(struct seq_file *m, void *v)
1372 {
1373 	struct nfs_server *server;
1374 	struct nfs_client *clp;
1375 	char dev[8], fsid[17];
1376 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1377 
1378 	/* display header on line 1 */
1379 	if (v == &nn->nfs_volume_list) {
1380 		seq_puts(m, "NV SERVER   PORT DEV     FSID              FSC\n");
1381 		return 0;
1382 	}
1383 	/* display one transport per line on subsequent lines */
1384 	server = list_entry(v, struct nfs_server, master_link);
1385 	clp = server->nfs_client;
1386 
1387 	snprintf(dev, 8, "%u:%u",
1388 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1389 
1390 	snprintf(fsid, 17, "%llx:%llx",
1391 		 (unsigned long long) server->fsid.major,
1392 		 (unsigned long long) server->fsid.minor);
1393 
1394 	rcu_read_lock();
1395 	seq_printf(m, "v%u %s %s %-7s %-17s %s\n",
1396 		   clp->rpc_ops->version,
1397 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1398 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1399 		   dev,
1400 		   fsid,
1401 		   nfs_server_fscache_state(server));
1402 	rcu_read_unlock();
1403 
1404 	return 0;
1405 }
1406 
1407 /*
1408  * initialise the /proc/fs/nfsfs/ directory
1409  */
1410 int __init nfs_fs_proc_init(void)
1411 {
1412 	struct proc_dir_entry *p;
1413 
1414 	proc_fs_nfs = proc_mkdir("fs/nfsfs", NULL);
1415 	if (!proc_fs_nfs)
1416 		goto error_0;
1417 
1418 	/* a file of servers with which we're dealing */
1419 	p = proc_create("servers", S_IFREG|S_IRUGO,
1420 			proc_fs_nfs, &nfs_server_list_fops);
1421 	if (!p)
1422 		goto error_1;
1423 
1424 	/* a file of volumes that we have mounted */
1425 	p = proc_create("volumes", S_IFREG|S_IRUGO,
1426 			proc_fs_nfs, &nfs_volume_list_fops);
1427 	if (!p)
1428 		goto error_2;
1429 	return 0;
1430 
1431 error_2:
1432 	remove_proc_entry("servers", proc_fs_nfs);
1433 error_1:
1434 	remove_proc_entry("fs/nfsfs", NULL);
1435 error_0:
1436 	return -ENOMEM;
1437 }
1438 
1439 /*
1440  * clean up the /proc/fs/nfsfs/ directory
1441  */
1442 void nfs_fs_proc_exit(void)
1443 {
1444 	remove_proc_entry("volumes", proc_fs_nfs);
1445 	remove_proc_entry("servers", proc_fs_nfs);
1446 	remove_proc_entry("fs/nfsfs", NULL);
1447 }
1448 
1449 #endif /* CONFIG_PROC_FS */
1450