xref: /linux/fs/nfs/client.c (revision 2a2c74b2efcb1a0ca3fdcb5fbb96ad8de6a29177)
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 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 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 	dprintk("--> nfs_free_client(%u)\n", clp->rpc_ops->version);
242 
243 	nfs_fscache_release_client_cookie(clp);
244 
245 	/* -EIO all pending I/O */
246 	if (!IS_ERR(clp->cl_rpcclient))
247 		rpc_shutdown_client(clp->cl_rpcclient);
248 
249 	if (clp->cl_machine_cred != NULL)
250 		put_rpccred(clp->cl_machine_cred);
251 
252 	put_net(clp->cl_net);
253 	put_nfs_version(clp->cl_nfs_mod);
254 	kfree(clp->cl_hostname);
255 	kfree(clp);
256 
257 	dprintk("<-- nfs_free_client()\n");
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 	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
272 	nn = net_generic(clp->cl_net, nfs_net_id);
273 
274 	if (atomic_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
275 		list_del(&clp->cl_share_link);
276 		nfs_cb_idr_remove_locked(clp);
277 		spin_unlock(&nn->nfs_client_lock);
278 
279 		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
280 
281 		clp->rpc_ops->free_client(clp);
282 	}
283 }
284 EXPORT_SYMBOL_GPL(nfs_put_client);
285 
286 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
287 /*
288  * Test if two ip6 socket addresses refer to the same socket by
289  * comparing relevant fields. The padding bytes specifically, are not
290  * compared. sin6_flowinfo is not compared because it only affects QoS
291  * and sin6_scope_id is only compared if the address is "link local"
292  * because "link local" addresses need only be unique to a specific
293  * link. Conversely, ordinary unicast addresses might have different
294  * sin6_scope_id.
295  *
296  * The caller should ensure both socket addresses are AF_INET6.
297  */
298 static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
299 				      const struct sockaddr *sa2)
300 {
301 	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
302 	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
303 
304 	if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
305 		return 0;
306 	else if (ipv6_addr_type(&sin1->sin6_addr) & IPV6_ADDR_LINKLOCAL)
307 		return sin1->sin6_scope_id == sin2->sin6_scope_id;
308 
309 	return 1;
310 }
311 #else	/* !defined(CONFIG_IPV6) && !defined(CONFIG_IPV6_MODULE) */
312 static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
313 				      const struct sockaddr *sa2)
314 {
315 	return 0;
316 }
317 #endif
318 
319 /*
320  * Test if two ip4 socket addresses refer to the same socket, by
321  * comparing relevant fields. The padding bytes specifically, are
322  * not compared.
323  *
324  * The caller should ensure both socket addresses are AF_INET.
325  */
326 static int nfs_sockaddr_match_ipaddr4(const struct sockaddr *sa1,
327 				      const struct sockaddr *sa2)
328 {
329 	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
330 	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
331 
332 	return sin1->sin_addr.s_addr == sin2->sin_addr.s_addr;
333 }
334 
335 static int nfs_sockaddr_cmp_ip6(const struct sockaddr *sa1,
336 				const struct sockaddr *sa2)
337 {
338 	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
339 	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
340 
341 	return nfs_sockaddr_match_ipaddr6(sa1, sa2) &&
342 		(sin1->sin6_port == sin2->sin6_port);
343 }
344 
345 static int nfs_sockaddr_cmp_ip4(const struct sockaddr *sa1,
346 				const struct sockaddr *sa2)
347 {
348 	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
349 	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
350 
351 	return nfs_sockaddr_match_ipaddr4(sa1, sa2) &&
352 		(sin1->sin_port == sin2->sin_port);
353 }
354 
355 #if defined(CONFIG_NFS_V4_1)
356 /*
357  * Test if two socket addresses represent the same actual socket,
358  * by comparing (only) relevant fields, excluding the port number.
359  */
360 int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
361 			      const struct sockaddr *sa2)
362 {
363 	if (sa1->sa_family != sa2->sa_family)
364 		return 0;
365 
366 	switch (sa1->sa_family) {
367 	case AF_INET:
368 		return nfs_sockaddr_match_ipaddr4(sa1, sa2);
369 	case AF_INET6:
370 		return nfs_sockaddr_match_ipaddr6(sa1, sa2);
371 	}
372 	return 0;
373 }
374 EXPORT_SYMBOL_GPL(nfs_sockaddr_match_ipaddr);
375 #endif /* CONFIG_NFS_V4_1 */
376 
377 /*
378  * Test if two socket addresses represent the same actual socket,
379  * by comparing (only) relevant fields, including the port number.
380  */
381 static int nfs_sockaddr_cmp(const struct sockaddr *sa1,
382 			    const struct sockaddr *sa2)
383 {
384 	if (sa1->sa_family != sa2->sa_family)
385 		return 0;
386 
387 	switch (sa1->sa_family) {
388 	case AF_INET:
389 		return nfs_sockaddr_cmp_ip4(sa1, sa2);
390 	case AF_INET6:
391 		return nfs_sockaddr_cmp_ip6(sa1, sa2);
392 	}
393 	return 0;
394 }
395 
396 /*
397  * Find an nfs_client on the list that matches the initialisation data
398  * that is supplied.
399  */
400 static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
401 {
402 	struct nfs_client *clp;
403 	const struct sockaddr *sap = data->addr;
404 	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
405 
406 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
407 	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
408 		/* Don't match clients that failed to initialise properly */
409 		if (clp->cl_cons_state < 0)
410 			continue;
411 
412 		/* Different NFS versions cannot share the same nfs_client */
413 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
414 			continue;
415 
416 		if (clp->cl_proto != data->proto)
417 			continue;
418 		/* Match nfsv4 minorversion */
419 		if (clp->cl_minorversion != data->minorversion)
420 			continue;
421 		/* Match the full socket address */
422 		if (!nfs_sockaddr_cmp(sap, clap))
423 			continue;
424 
425 		atomic_inc(&clp->cl_count);
426 		return clp;
427 	}
428 	return NULL;
429 }
430 
431 static bool nfs_client_init_is_complete(const struct nfs_client *clp)
432 {
433 	return clp->cl_cons_state != NFS_CS_INITING;
434 }
435 
436 int nfs_wait_client_init_complete(const struct nfs_client *clp)
437 {
438 	return wait_event_killable(nfs_client_active_wq,
439 			nfs_client_init_is_complete(clp));
440 }
441 EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
442 
443 /*
444  * Found an existing client.  Make sure it's ready before returning.
445  */
446 static struct nfs_client *
447 nfs_found_client(const struct nfs_client_initdata *cl_init,
448 		 struct nfs_client *clp)
449 {
450 	int error;
451 
452 	error = nfs_wait_client_init_complete(clp);
453 	if (error < 0) {
454 		nfs_put_client(clp);
455 		return ERR_PTR(-ERESTARTSYS);
456 	}
457 
458 	if (clp->cl_cons_state < NFS_CS_READY) {
459 		error = clp->cl_cons_state;
460 		nfs_put_client(clp);
461 		return ERR_PTR(error);
462 	}
463 
464 	smp_rmb();
465 
466 	dprintk("<-- %s found nfs_client %p for %s\n",
467 		__func__, clp, cl_init->hostname ?: "");
468 	return clp;
469 }
470 
471 /*
472  * Look up a client by IP address and protocol version
473  * - creates a new record if one doesn't yet exist
474  */
475 struct nfs_client *
476 nfs_get_client(const struct nfs_client_initdata *cl_init,
477 	       const struct rpc_timeout *timeparms,
478 	       const char *ip_addr,
479 	       rpc_authflavor_t authflavour)
480 {
481 	struct nfs_client *clp, *new = NULL;
482 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
483 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
484 
485 	dprintk("--> nfs_get_client(%s,v%u)\n",
486 		cl_init->hostname ?: "", rpc_ops->version);
487 
488 	/* see if the client already exists */
489 	do {
490 		spin_lock(&nn->nfs_client_lock);
491 
492 		clp = nfs_match_client(cl_init);
493 		if (clp) {
494 			spin_unlock(&nn->nfs_client_lock);
495 			if (new)
496 				new->rpc_ops->free_client(new);
497 			return nfs_found_client(cl_init, clp);
498 		}
499 		if (new) {
500 			list_add_tail(&new->cl_share_link,
501 					&nn->nfs_client_list);
502 			spin_unlock(&nn->nfs_client_lock);
503 			new->cl_flags = cl_init->init_flags;
504 			return rpc_ops->init_client(new, timeparms, ip_addr);
505 		}
506 
507 		spin_unlock(&nn->nfs_client_lock);
508 
509 		new = rpc_ops->alloc_client(cl_init);
510 	} while (!IS_ERR(new));
511 
512 	dprintk("<-- nfs_get_client() Failed to find %s (%ld)\n",
513 		cl_init->hostname ?: "", PTR_ERR(new));
514 	return new;
515 }
516 EXPORT_SYMBOL_GPL(nfs_get_client);
517 
518 /*
519  * Mark a server as ready or failed
520  */
521 void nfs_mark_client_ready(struct nfs_client *clp, int state)
522 {
523 	smp_wmb();
524 	clp->cl_cons_state = state;
525 	wake_up_all(&nfs_client_active_wq);
526 }
527 EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
528 
529 /*
530  * Initialise the timeout values for a connection
531  */
532 void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
533 				    unsigned int timeo, unsigned int retrans)
534 {
535 	to->to_initval = timeo * HZ / 10;
536 	to->to_retries = retrans;
537 
538 	switch (proto) {
539 	case XPRT_TRANSPORT_TCP:
540 	case XPRT_TRANSPORT_RDMA:
541 		if (to->to_retries == 0)
542 			to->to_retries = NFS_DEF_TCP_RETRANS;
543 		if (to->to_initval == 0)
544 			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
545 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
546 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
547 		to->to_increment = to->to_initval;
548 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
549 		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
550 			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
551 		if (to->to_maxval < to->to_initval)
552 			to->to_maxval = to->to_initval;
553 		to->to_exponential = 0;
554 		break;
555 	case XPRT_TRANSPORT_UDP:
556 		if (to->to_retries == 0)
557 			to->to_retries = NFS_DEF_UDP_RETRANS;
558 		if (!to->to_initval)
559 			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
560 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
561 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
562 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
563 		to->to_exponential = 1;
564 		break;
565 	default:
566 		BUG();
567 	}
568 }
569 EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
570 
571 /*
572  * Create an RPC client handle
573  */
574 int nfs_create_rpc_client(struct nfs_client *clp,
575 			  const struct rpc_timeout *timeparms,
576 			  rpc_authflavor_t flavor)
577 {
578 	struct rpc_clnt		*clnt = NULL;
579 	struct rpc_create_args args = {
580 		.net		= clp->cl_net,
581 		.protocol	= clp->cl_proto,
582 		.address	= (struct sockaddr *)&clp->cl_addr,
583 		.addrsize	= clp->cl_addrlen,
584 		.timeout	= timeparms,
585 		.servername	= clp->cl_hostname,
586 		.program	= &nfs_program,
587 		.version	= clp->rpc_ops->version,
588 		.authflavor	= flavor,
589 	};
590 
591 	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
592 		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
593 	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
594 		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
595 	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
596 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
597 	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
598 		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
599 
600 	if (!IS_ERR(clp->cl_rpcclient))
601 		return 0;
602 
603 	clnt = rpc_create(&args);
604 	if (IS_ERR(clnt)) {
605 		dprintk("%s: cannot create RPC client. Error = %ld\n",
606 				__func__, PTR_ERR(clnt));
607 		return PTR_ERR(clnt);
608 	}
609 
610 	clp->cl_rpcclient = clnt;
611 	return 0;
612 }
613 EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
614 
615 /*
616  * Version 2 or 3 client destruction
617  */
618 static void nfs_destroy_server(struct nfs_server *server)
619 {
620 	if (server->nlm_host)
621 		nlmclnt_done(server->nlm_host);
622 }
623 
624 /*
625  * Version 2 or 3 lockd setup
626  */
627 static int nfs_start_lockd(struct nfs_server *server)
628 {
629 	struct nlm_host *host;
630 	struct nfs_client *clp = server->nfs_client;
631 	struct nlmclnt_initdata nlm_init = {
632 		.hostname	= clp->cl_hostname,
633 		.address	= (struct sockaddr *)&clp->cl_addr,
634 		.addrlen	= clp->cl_addrlen,
635 		.nfs_version	= clp->rpc_ops->version,
636 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
637 					1 : 0,
638 		.net		= clp->cl_net,
639 	};
640 
641 	if (nlm_init.nfs_version > 3)
642 		return 0;
643 	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
644 			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
645 		return 0;
646 
647 	switch (clp->cl_proto) {
648 		default:
649 			nlm_init.protocol = IPPROTO_TCP;
650 			break;
651 		case XPRT_TRANSPORT_UDP:
652 			nlm_init.protocol = IPPROTO_UDP;
653 	}
654 
655 	host = nlmclnt_init(&nlm_init);
656 	if (IS_ERR(host))
657 		return PTR_ERR(host);
658 
659 	server->nlm_host = host;
660 	server->destroy = nfs_destroy_server;
661 	return 0;
662 }
663 
664 /*
665  * Create a general RPC client
666  */
667 int nfs_init_server_rpcclient(struct nfs_server *server,
668 		const struct rpc_timeout *timeo,
669 		rpc_authflavor_t pseudoflavour)
670 {
671 	struct nfs_client *clp = server->nfs_client;
672 
673 	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
674 							pseudoflavour);
675 	if (IS_ERR(server->client)) {
676 		dprintk("%s: couldn't create rpc_client!\n", __func__);
677 		return PTR_ERR(server->client);
678 	}
679 
680 	memcpy(&server->client->cl_timeout_default,
681 			timeo,
682 			sizeof(server->client->cl_timeout_default));
683 	server->client->cl_timeout = &server->client->cl_timeout_default;
684 	server->client->cl_softrtry = 0;
685 	if (server->flags & NFS_MOUNT_SOFT)
686 		server->client->cl_softrtry = 1;
687 
688 	return 0;
689 }
690 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
691 
692 /**
693  * nfs_init_client - Initialise an NFS2 or NFS3 client
694  *
695  * @clp: nfs_client to initialise
696  * @timeparms: timeout parameters for underlying RPC transport
697  * @ip_addr: IP presentation address (not used)
698  *
699  * Returns pointer to an NFS client, or an ERR_PTR value.
700  */
701 struct nfs_client *nfs_init_client(struct nfs_client *clp,
702 		    const struct rpc_timeout *timeparms,
703 		    const char *ip_addr)
704 {
705 	int error;
706 
707 	if (clp->cl_cons_state == NFS_CS_READY) {
708 		/* the client is already initialised */
709 		dprintk("<-- nfs_init_client() = 0 [already %p]\n", clp);
710 		return clp;
711 	}
712 
713 	/*
714 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
715 	 * - RFC 2623, sec 2.3.2
716 	 */
717 	error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_UNIX);
718 	if (error < 0)
719 		goto error;
720 	nfs_mark_client_ready(clp, NFS_CS_READY);
721 	return clp;
722 
723 error:
724 	nfs_mark_client_ready(clp, error);
725 	nfs_put_client(clp);
726 	dprintk("<-- nfs_init_client() = xerror %d\n", error);
727 	return ERR_PTR(error);
728 }
729 EXPORT_SYMBOL_GPL(nfs_init_client);
730 
731 /*
732  * Create a version 2 or 3 client
733  */
734 static int nfs_init_server(struct nfs_server *server,
735 			   const struct nfs_parsed_mount_data *data,
736 			   struct nfs_subversion *nfs_mod)
737 {
738 	struct nfs_client_initdata cl_init = {
739 		.hostname = data->nfs_server.hostname,
740 		.addr = (const struct sockaddr *)&data->nfs_server.address,
741 		.addrlen = data->nfs_server.addrlen,
742 		.nfs_mod = nfs_mod,
743 		.proto = data->nfs_server.protocol,
744 		.net = data->net,
745 	};
746 	struct rpc_timeout timeparms;
747 	struct nfs_client *clp;
748 	int error;
749 
750 	dprintk("--> nfs_init_server()\n");
751 
752 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
753 			data->timeo, data->retrans);
754 	if (data->flags & NFS_MOUNT_NORESVPORT)
755 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
756 
757 	/* Allocate or find a client reference we can use */
758 	clp = nfs_get_client(&cl_init, &timeparms, NULL, RPC_AUTH_UNIX);
759 	if (IS_ERR(clp)) {
760 		dprintk("<-- nfs_init_server() = error %ld\n", PTR_ERR(clp));
761 		return PTR_ERR(clp);
762 	}
763 
764 	server->nfs_client = clp;
765 
766 	/* Initialise the client representation from the mount data */
767 	server->flags = data->flags;
768 	server->options = data->options;
769 	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
770 		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
771 		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME|NFS_CAP_CHANGE_ATTR;
772 
773 	if (data->rsize)
774 		server->rsize = nfs_block_size(data->rsize, NULL);
775 	if (data->wsize)
776 		server->wsize = nfs_block_size(data->wsize, NULL);
777 
778 	server->acregmin = data->acregmin * HZ;
779 	server->acregmax = data->acregmax * HZ;
780 	server->acdirmin = data->acdirmin * HZ;
781 	server->acdirmax = data->acdirmax * HZ;
782 
783 	/* Start lockd here, before we might error out */
784 	error = nfs_start_lockd(server);
785 	if (error < 0)
786 		goto error;
787 
788 	server->port = data->nfs_server.port;
789 	server->auth_info = data->auth_info;
790 
791 	error = nfs_init_server_rpcclient(server, &timeparms,
792 					  data->selected_flavor);
793 	if (error < 0)
794 		goto error;
795 
796 	/* Preserve the values of mount_server-related mount options */
797 	if (data->mount_server.addrlen) {
798 		memcpy(&server->mountd_address, &data->mount_server.address,
799 			data->mount_server.addrlen);
800 		server->mountd_addrlen = data->mount_server.addrlen;
801 	}
802 	server->mountd_version = data->mount_server.version;
803 	server->mountd_port = data->mount_server.port;
804 	server->mountd_protocol = data->mount_server.protocol;
805 
806 	server->namelen  = data->namlen;
807 	dprintk("<-- nfs_init_server() = 0 [new %p]\n", clp);
808 	return 0;
809 
810 error:
811 	server->nfs_client = NULL;
812 	nfs_put_client(clp);
813 	dprintk("<-- nfs_init_server() = xerror %d\n", error);
814 	return error;
815 }
816 
817 /*
818  * Load up the server record from information gained in an fsinfo record
819  */
820 static void nfs_server_set_fsinfo(struct nfs_server *server,
821 				  struct nfs_fh *mntfh,
822 				  struct nfs_fsinfo *fsinfo)
823 {
824 	unsigned long max_rpc_payload;
825 
826 	/* Work out a lot of parameters */
827 	if (server->rsize == 0)
828 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
829 	if (server->wsize == 0)
830 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
831 
832 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
833 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
834 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
835 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
836 
837 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
838 	if (server->rsize > max_rpc_payload)
839 		server->rsize = max_rpc_payload;
840 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
841 		server->rsize = NFS_MAX_FILE_IO_SIZE;
842 	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
843 
844 	server->backing_dev_info.name = "nfs";
845 	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
846 
847 	if (server->wsize > max_rpc_payload)
848 		server->wsize = max_rpc_payload;
849 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
850 		server->wsize = NFS_MAX_FILE_IO_SIZE;
851 	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
852 
853 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
854 
855 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
856 	if (server->dtsize > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES)
857 		server->dtsize = PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES;
858 	if (server->dtsize > server->rsize)
859 		server->dtsize = server->rsize;
860 
861 	if (server->flags & NFS_MOUNT_NOAC) {
862 		server->acregmin = server->acregmax = 0;
863 		server->acdirmin = server->acdirmax = 0;
864 	}
865 
866 	server->maxfilesize = fsinfo->maxfilesize;
867 
868 	server->time_delta = fsinfo->time_delta;
869 
870 	/* We're airborne Set socket buffersize */
871 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
872 }
873 
874 /*
875  * Probe filesystem information, including the FSID on v2/v3
876  */
877 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
878 {
879 	struct nfs_fsinfo fsinfo;
880 	struct nfs_client *clp = server->nfs_client;
881 	int error;
882 
883 	dprintk("--> nfs_probe_fsinfo()\n");
884 
885 	if (clp->rpc_ops->set_capabilities != NULL) {
886 		error = clp->rpc_ops->set_capabilities(server, mntfh);
887 		if (error < 0)
888 			goto out_error;
889 	}
890 
891 	fsinfo.fattr = fattr;
892 	fsinfo.layouttype = 0;
893 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
894 	if (error < 0)
895 		goto out_error;
896 
897 	nfs_server_set_fsinfo(server, mntfh, &fsinfo);
898 
899 	/* Get some general file system info */
900 	if (server->namelen == 0) {
901 		struct nfs_pathconf pathinfo;
902 
903 		pathinfo.fattr = fattr;
904 		nfs_fattr_init(fattr);
905 
906 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
907 			server->namelen = pathinfo.max_namelen;
908 	}
909 
910 	dprintk("<-- nfs_probe_fsinfo() = 0\n");
911 	return 0;
912 
913 out_error:
914 	dprintk("nfs_probe_fsinfo: error = %d\n", -error);
915 	return error;
916 }
917 EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
918 
919 /*
920  * Copy useful information when duplicating a server record
921  */
922 void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
923 {
924 	target->flags = source->flags;
925 	target->rsize = source->rsize;
926 	target->wsize = source->wsize;
927 	target->acregmin = source->acregmin;
928 	target->acregmax = source->acregmax;
929 	target->acdirmin = source->acdirmin;
930 	target->acdirmax = source->acdirmax;
931 	target->caps = source->caps;
932 	target->options = source->options;
933 	target->auth_info = source->auth_info;
934 }
935 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
936 
937 void nfs_server_insert_lists(struct nfs_server *server)
938 {
939 	struct nfs_client *clp = server->nfs_client;
940 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
941 
942 	spin_lock(&nn->nfs_client_lock);
943 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
944 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
945 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
946 	spin_unlock(&nn->nfs_client_lock);
947 
948 }
949 EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
950 
951 void nfs_server_remove_lists(struct nfs_server *server)
952 {
953 	struct nfs_client *clp = server->nfs_client;
954 	struct nfs_net *nn;
955 
956 	if (clp == NULL)
957 		return;
958 	nn = net_generic(clp->cl_net, nfs_net_id);
959 	spin_lock(&nn->nfs_client_lock);
960 	list_del_rcu(&server->client_link);
961 	if (list_empty(&clp->cl_superblocks))
962 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
963 	list_del(&server->master_link);
964 	spin_unlock(&nn->nfs_client_lock);
965 
966 	synchronize_rcu();
967 }
968 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
969 
970 /*
971  * Allocate and initialise a server record
972  */
973 struct nfs_server *nfs_alloc_server(void)
974 {
975 	struct nfs_server *server;
976 
977 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
978 	if (!server)
979 		return NULL;
980 
981 	server->client = server->client_acl = ERR_PTR(-EINVAL);
982 
983 	/* Zero out the NFS state stuff */
984 	INIT_LIST_HEAD(&server->client_link);
985 	INIT_LIST_HEAD(&server->master_link);
986 	INIT_LIST_HEAD(&server->delegations);
987 	INIT_LIST_HEAD(&server->layouts);
988 	INIT_LIST_HEAD(&server->state_owners_lru);
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 	if (bdi_init(&server->backing_dev_info)) {
999 		nfs_free_iostats(server->io_stats);
1000 		kfree(server);
1001 		return NULL;
1002 	}
1003 
1004 	ida_init(&server->openowner_id);
1005 	ida_init(&server->lockowner_id);
1006 	pnfs_init_server(server);
1007 
1008 	return server;
1009 }
1010 EXPORT_SYMBOL_GPL(nfs_alloc_server);
1011 
1012 /*
1013  * Free up a server record
1014  */
1015 void nfs_free_server(struct nfs_server *server)
1016 {
1017 	dprintk("--> nfs_free_server()\n");
1018 
1019 	nfs_server_remove_lists(server);
1020 
1021 	if (server->destroy != NULL)
1022 		server->destroy(server);
1023 
1024 	if (!IS_ERR(server->client_acl))
1025 		rpc_shutdown_client(server->client_acl);
1026 	if (!IS_ERR(server->client))
1027 		rpc_shutdown_client(server->client);
1028 
1029 	nfs_put_client(server->nfs_client);
1030 
1031 	ida_destroy(&server->lockowner_id);
1032 	ida_destroy(&server->openowner_id);
1033 	nfs_free_iostats(server->io_stats);
1034 	bdi_destroy(&server->backing_dev_info);
1035 	kfree(server);
1036 	nfs_release_automount_timer();
1037 	dprintk("<-- nfs_free_server()\n");
1038 }
1039 EXPORT_SYMBOL_GPL(nfs_free_server);
1040 
1041 /*
1042  * Create a version 2 or 3 volume record
1043  * - keyed on server and FSID
1044  */
1045 struct nfs_server *nfs_create_server(struct nfs_mount_info *mount_info,
1046 				     struct nfs_subversion *nfs_mod)
1047 {
1048 	struct nfs_server *server;
1049 	struct nfs_fattr *fattr;
1050 	int error;
1051 
1052 	server = nfs_alloc_server();
1053 	if (!server)
1054 		return ERR_PTR(-ENOMEM);
1055 
1056 	error = -ENOMEM;
1057 	fattr = nfs_alloc_fattr();
1058 	if (fattr == NULL)
1059 		goto error;
1060 
1061 	/* Get a client representation */
1062 	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
1063 	if (error < 0)
1064 		goto error;
1065 
1066 	/* Probe the root fh to retrieve its FSID */
1067 	error = nfs_probe_fsinfo(server, mount_info->mntfh, fattr);
1068 	if (error < 0)
1069 		goto error;
1070 	if (server->nfs_client->rpc_ops->version == 3) {
1071 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
1072 			server->namelen = NFS3_MAXNAMLEN;
1073 		if (!(mount_info->parsed->flags & NFS_MOUNT_NORDIRPLUS))
1074 			server->caps |= NFS_CAP_READDIRPLUS;
1075 	} else {
1076 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
1077 			server->namelen = NFS2_MAXNAMLEN;
1078 	}
1079 
1080 	if (!(fattr->valid & NFS_ATTR_FATTR)) {
1081 		error = nfs_mod->rpc_ops->getattr(server, mount_info->mntfh, fattr, NULL);
1082 		if (error < 0) {
1083 			dprintk("nfs_create_server: getattr error = %d\n", -error);
1084 			goto error;
1085 		}
1086 	}
1087 	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
1088 
1089 	dprintk("Server FSID: %llx:%llx\n",
1090 		(unsigned long long) server->fsid.major,
1091 		(unsigned long long) server->fsid.minor);
1092 
1093 	nfs_server_insert_lists(server);
1094 	server->mount_time = jiffies;
1095 	nfs_free_fattr(fattr);
1096 	return server;
1097 
1098 error:
1099 	nfs_free_fattr(fattr);
1100 	nfs_free_server(server);
1101 	return ERR_PTR(error);
1102 }
1103 EXPORT_SYMBOL_GPL(nfs_create_server);
1104 
1105 /*
1106  * Clone an NFS2, NFS3 or NFS4 server record
1107  */
1108 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1109 				    struct nfs_fh *fh,
1110 				    struct nfs_fattr *fattr,
1111 				    rpc_authflavor_t flavor)
1112 {
1113 	struct nfs_server *server;
1114 	struct nfs_fattr *fattr_fsinfo;
1115 	int error;
1116 
1117 	dprintk("--> nfs_clone_server(,%llx:%llx,)\n",
1118 		(unsigned long long) fattr->fsid.major,
1119 		(unsigned long long) fattr->fsid.minor);
1120 
1121 	server = nfs_alloc_server();
1122 	if (!server)
1123 		return ERR_PTR(-ENOMEM);
1124 
1125 	error = -ENOMEM;
1126 	fattr_fsinfo = nfs_alloc_fattr();
1127 	if (fattr_fsinfo == NULL)
1128 		goto out_free_server;
1129 
1130 	/* Copy data from the source */
1131 	server->nfs_client = source->nfs_client;
1132 	server->destroy = source->destroy;
1133 	atomic_inc(&server->nfs_client->cl_count);
1134 	nfs_server_copy_userdata(server, source);
1135 
1136 	server->fsid = fattr->fsid;
1137 
1138 	error = nfs_init_server_rpcclient(server,
1139 			source->client->cl_timeout,
1140 			flavor);
1141 	if (error < 0)
1142 		goto out_free_server;
1143 
1144 	/* probe the filesystem info for this server filesystem */
1145 	error = nfs_probe_fsinfo(server, fh, fattr_fsinfo);
1146 	if (error < 0)
1147 		goto out_free_server;
1148 
1149 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1150 		server->namelen = NFS4_MAXNAMLEN;
1151 
1152 	dprintk("Cloned FSID: %llx:%llx\n",
1153 		(unsigned long long) server->fsid.major,
1154 		(unsigned long long) server->fsid.minor);
1155 
1156 	error = nfs_start_lockd(server);
1157 	if (error < 0)
1158 		goto out_free_server;
1159 
1160 	nfs_server_insert_lists(server);
1161 	server->mount_time = jiffies;
1162 
1163 	nfs_free_fattr(fattr_fsinfo);
1164 	dprintk("<-- nfs_clone_server() = %p\n", server);
1165 	return server;
1166 
1167 out_free_server:
1168 	nfs_free_fattr(fattr_fsinfo);
1169 	nfs_free_server(server);
1170 	dprintk("<-- nfs_clone_server() = error %d\n", error);
1171 	return ERR_PTR(error);
1172 }
1173 EXPORT_SYMBOL_GPL(nfs_clone_server);
1174 
1175 void nfs_clients_init(struct net *net)
1176 {
1177 	struct nfs_net *nn = net_generic(net, nfs_net_id);
1178 
1179 	INIT_LIST_HEAD(&nn->nfs_client_list);
1180 	INIT_LIST_HEAD(&nn->nfs_volume_list);
1181 #if IS_ENABLED(CONFIG_NFS_V4)
1182 	idr_init(&nn->cb_ident_idr);
1183 #endif
1184 	spin_lock_init(&nn->nfs_client_lock);
1185 	nn->boot_time = CURRENT_TIME;
1186 }
1187 
1188 #ifdef CONFIG_PROC_FS
1189 static struct proc_dir_entry *proc_fs_nfs;
1190 
1191 static int nfs_server_list_open(struct inode *inode, struct file *file);
1192 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1193 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1194 static void nfs_server_list_stop(struct seq_file *p, void *v);
1195 static int nfs_server_list_show(struct seq_file *m, void *v);
1196 
1197 static const struct seq_operations nfs_server_list_ops = {
1198 	.start	= nfs_server_list_start,
1199 	.next	= nfs_server_list_next,
1200 	.stop	= nfs_server_list_stop,
1201 	.show	= nfs_server_list_show,
1202 };
1203 
1204 static const struct file_operations nfs_server_list_fops = {
1205 	.open		= nfs_server_list_open,
1206 	.read		= seq_read,
1207 	.llseek		= seq_lseek,
1208 	.release	= seq_release,
1209 	.owner		= THIS_MODULE,
1210 };
1211 
1212 static int nfs_volume_list_open(struct inode *inode, struct file *file);
1213 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1214 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1215 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1216 static int nfs_volume_list_show(struct seq_file *m, void *v);
1217 
1218 static const struct seq_operations nfs_volume_list_ops = {
1219 	.start	= nfs_volume_list_start,
1220 	.next	= nfs_volume_list_next,
1221 	.stop	= nfs_volume_list_stop,
1222 	.show	= nfs_volume_list_show,
1223 };
1224 
1225 static const struct file_operations nfs_volume_list_fops = {
1226 	.open		= nfs_volume_list_open,
1227 	.read		= seq_read,
1228 	.llseek		= seq_lseek,
1229 	.release	= seq_release,
1230 	.owner		= THIS_MODULE,
1231 };
1232 
1233 /*
1234  * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
1235  * we're dealing
1236  */
1237 static int nfs_server_list_open(struct inode *inode, struct file *file)
1238 {
1239 	struct seq_file *m;
1240 	int ret;
1241 	struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
1242 	struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
1243 
1244 	ret = seq_open(file, &nfs_server_list_ops);
1245 	if (ret < 0)
1246 		return ret;
1247 
1248 	m = file->private_data;
1249 	m->private = net;
1250 
1251 	return 0;
1252 }
1253 
1254 /*
1255  * set up the iterator to start reading from the server list and return the first item
1256  */
1257 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1258 {
1259 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1260 
1261 	/* lock the list against modification */
1262 	spin_lock(&nn->nfs_client_lock);
1263 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
1264 }
1265 
1266 /*
1267  * move to next server
1268  */
1269 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1270 {
1271 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1272 
1273 	return seq_list_next(v, &nn->nfs_client_list, pos);
1274 }
1275 
1276 /*
1277  * clean up after reading from the transports list
1278  */
1279 static void nfs_server_list_stop(struct seq_file *p, void *v)
1280 {
1281 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1282 
1283 	spin_unlock(&nn->nfs_client_lock);
1284 }
1285 
1286 /*
1287  * display a header line followed by a load of call lines
1288  */
1289 static int nfs_server_list_show(struct seq_file *m, void *v)
1290 {
1291 	struct nfs_client *clp;
1292 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1293 
1294 	/* display header on line 1 */
1295 	if (v == &nn->nfs_client_list) {
1296 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1297 		return 0;
1298 	}
1299 
1300 	/* display one transport per line on subsequent lines */
1301 	clp = list_entry(v, struct nfs_client, cl_share_link);
1302 
1303 	/* Check if the client is initialized */
1304 	if (clp->cl_cons_state != NFS_CS_READY)
1305 		return 0;
1306 
1307 	rcu_read_lock();
1308 	seq_printf(m, "v%u %s %s %3d %s\n",
1309 		   clp->rpc_ops->version,
1310 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1311 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1312 		   atomic_read(&clp->cl_count),
1313 		   clp->cl_hostname);
1314 	rcu_read_unlock();
1315 
1316 	return 0;
1317 }
1318 
1319 /*
1320  * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
1321  */
1322 static int nfs_volume_list_open(struct inode *inode, struct file *file)
1323 {
1324 	struct seq_file *m;
1325 	int ret;
1326 	struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
1327 	struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
1328 
1329 	ret = seq_open(file, &nfs_volume_list_ops);
1330 	if (ret < 0)
1331 		return ret;
1332 
1333 	m = file->private_data;
1334 	m->private = net;
1335 
1336 	return 0;
1337 }
1338 
1339 /*
1340  * set up the iterator to start reading from the volume list and return the first item
1341  */
1342 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1343 {
1344 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1345 
1346 	/* lock the list against modification */
1347 	spin_lock(&nn->nfs_client_lock);
1348 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
1349 }
1350 
1351 /*
1352  * move to next volume
1353  */
1354 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1355 {
1356 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1357 
1358 	return seq_list_next(v, &nn->nfs_volume_list, pos);
1359 }
1360 
1361 /*
1362  * clean up after reading from the transports list
1363  */
1364 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1365 {
1366 	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
1367 
1368 	spin_unlock(&nn->nfs_client_lock);
1369 }
1370 
1371 /*
1372  * display a header line followed by a load of call lines
1373  */
1374 static int nfs_volume_list_show(struct seq_file *m, void *v)
1375 {
1376 	struct nfs_server *server;
1377 	struct nfs_client *clp;
1378 	char dev[8], fsid[17];
1379 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
1380 
1381 	/* display header on line 1 */
1382 	if (v == &nn->nfs_volume_list) {
1383 		seq_puts(m, "NV SERVER   PORT DEV     FSID              FSC\n");
1384 		return 0;
1385 	}
1386 	/* display one transport per line on subsequent lines */
1387 	server = list_entry(v, struct nfs_server, master_link);
1388 	clp = server->nfs_client;
1389 
1390 	snprintf(dev, 8, "%u:%u",
1391 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1392 
1393 	snprintf(fsid, 17, "%llx:%llx",
1394 		 (unsigned long long) server->fsid.major,
1395 		 (unsigned long long) server->fsid.minor);
1396 
1397 	rcu_read_lock();
1398 	seq_printf(m, "v%u %s %s %-7s %-17s %s\n",
1399 		   clp->rpc_ops->version,
1400 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
1401 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
1402 		   dev,
1403 		   fsid,
1404 		   nfs_server_fscache_state(server));
1405 	rcu_read_unlock();
1406 
1407 	return 0;
1408 }
1409 
1410 /*
1411  * initialise the /proc/fs/nfsfs/ directory
1412  */
1413 int __init nfs_fs_proc_init(void)
1414 {
1415 	struct proc_dir_entry *p;
1416 
1417 	proc_fs_nfs = proc_mkdir("fs/nfsfs", NULL);
1418 	if (!proc_fs_nfs)
1419 		goto error_0;
1420 
1421 	/* a file of servers with which we're dealing */
1422 	p = proc_create("servers", S_IFREG|S_IRUGO,
1423 			proc_fs_nfs, &nfs_server_list_fops);
1424 	if (!p)
1425 		goto error_1;
1426 
1427 	/* a file of volumes that we have mounted */
1428 	p = proc_create("volumes", S_IFREG|S_IRUGO,
1429 			proc_fs_nfs, &nfs_volume_list_fops);
1430 	if (!p)
1431 		goto error_2;
1432 	return 0;
1433 
1434 error_2:
1435 	remove_proc_entry("servers", proc_fs_nfs);
1436 error_1:
1437 	remove_proc_entry("fs/nfsfs", NULL);
1438 error_0:
1439 	return -ENOMEM;
1440 }
1441 
1442 /*
1443  * clean up the /proc/fs/nfsfs/ directory
1444  */
1445 void nfs_fs_proc_exit(void)
1446 {
1447 	remove_proc_entry("volumes", proc_fs_nfs);
1448 	remove_proc_entry("servers", proc_fs_nfs);
1449 	remove_proc_entry("fs/nfsfs", NULL);
1450 }
1451 
1452 #endif /* CONFIG_PROC_FS */
1453