xref: /linux/fs/nfs/client.c (revision a7edd0e676d51145ae634a2acf7a447e319200fa)
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 
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/nfs_fs.h>
27 #include <linux/nfs_mount.h>
28 #include <linux/nfs4_mount.h>
29 #include <linux/lockd/bind.h>
30 #include <linux/smp_lock.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/nfs_idmap.h>
34 #include <linux/vfs.h>
35 #include <linux/inet.h>
36 #include <linux/nfs_xdr.h>
37 
38 #include <asm/system.h>
39 
40 #include "nfs4_fs.h"
41 #include "callback.h"
42 #include "delegation.h"
43 #include "iostat.h"
44 #include "internal.h"
45 
46 #define NFSDBG_FACILITY		NFSDBG_CLIENT
47 
48 static DEFINE_SPINLOCK(nfs_client_lock);
49 static LIST_HEAD(nfs_client_list);
50 static LIST_HEAD(nfs_volume_list);
51 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
52 
53 /*
54  * RPC cruft for NFS
55  */
56 static struct rpc_version *nfs_version[5] = {
57 	[2]			= &nfs_version2,
58 #ifdef CONFIG_NFS_V3
59 	[3]			= &nfs_version3,
60 #endif
61 #ifdef CONFIG_NFS_V4
62 	[4]			= &nfs_version4,
63 #endif
64 };
65 
66 struct rpc_program nfs_program = {
67 	.name			= "nfs",
68 	.number			= NFS_PROGRAM,
69 	.nrvers			= ARRAY_SIZE(nfs_version),
70 	.version		= nfs_version,
71 	.stats			= &nfs_rpcstat,
72 	.pipe_dir_name		= "/nfs",
73 };
74 
75 struct rpc_stat nfs_rpcstat = {
76 	.program		= &nfs_program
77 };
78 
79 
80 #ifdef CONFIG_NFS_V3_ACL
81 static struct rpc_stat		nfsacl_rpcstat = { &nfsacl_program };
82 static struct rpc_version *	nfsacl_version[] = {
83 	[3]			= &nfsacl_version3,
84 };
85 
86 struct rpc_program		nfsacl_program = {
87 	.name			= "nfsacl",
88 	.number			= NFS_ACL_PROGRAM,
89 	.nrvers			= ARRAY_SIZE(nfsacl_version),
90 	.version		= nfsacl_version,
91 	.stats			= &nfsacl_rpcstat,
92 };
93 #endif  /* CONFIG_NFS_V3_ACL */
94 
95 /*
96  * Allocate a shared client record
97  *
98  * Since these are allocated/deallocated very rarely, we don't
99  * bother putting them in a slab cache...
100  */
101 static struct nfs_client *nfs_alloc_client(const char *hostname,
102 					   const struct sockaddr_in *addr,
103 					   int nfsversion)
104 {
105 	struct nfs_client *clp;
106 	int error;
107 
108 	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
109 		goto error_0;
110 
111 	error = rpciod_up();
112 	if (error < 0) {
113 		dprintk("%s: couldn't start rpciod! Error = %d\n",
114 				__FUNCTION__, error);
115 		goto error_1;
116 	}
117 	__set_bit(NFS_CS_RPCIOD, &clp->cl_res_state);
118 
119 	if (nfsversion == 4) {
120 		if (nfs_callback_up() < 0)
121 			goto error_2;
122 		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
123 	}
124 
125 	atomic_set(&clp->cl_count, 1);
126 	clp->cl_cons_state = NFS_CS_INITING;
127 
128 	clp->cl_nfsversion = nfsversion;
129 	memcpy(&clp->cl_addr, addr, sizeof(clp->cl_addr));
130 
131 	if (hostname) {
132 		clp->cl_hostname = kstrdup(hostname, GFP_KERNEL);
133 		if (!clp->cl_hostname)
134 			goto error_3;
135 	}
136 
137 	INIT_LIST_HEAD(&clp->cl_superblocks);
138 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
139 
140 #ifdef CONFIG_NFS_V4
141 	init_rwsem(&clp->cl_sem);
142 	INIT_LIST_HEAD(&clp->cl_delegations);
143 	INIT_LIST_HEAD(&clp->cl_state_owners);
144 	INIT_LIST_HEAD(&clp->cl_unused);
145 	spin_lock_init(&clp->cl_lock);
146 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
147 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
148 	clp->cl_boot_time = CURRENT_TIME;
149 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
150 #endif
151 
152 	return clp;
153 
154 error_3:
155 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
156 		nfs_callback_down();
157 error_2:
158 	rpciod_down();
159 	__clear_bit(NFS_CS_RPCIOD, &clp->cl_res_state);
160 error_1:
161 	kfree(clp);
162 error_0:
163 	return NULL;
164 }
165 
166 static void nfs4_shutdown_client(struct nfs_client *clp)
167 {
168 #ifdef CONFIG_NFS_V4
169 	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
170 		nfs4_kill_renewd(clp);
171 	while (!list_empty(&clp->cl_unused)) {
172 		struct nfs4_state_owner *sp;
173 
174 		sp = list_entry(clp->cl_unused.next,
175 				struct nfs4_state_owner,
176 				so_list);
177 		list_del(&sp->so_list);
178 		kfree(sp);
179 	}
180 	BUG_ON(!list_empty(&clp->cl_state_owners));
181 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
182 		nfs_idmap_delete(clp);
183 #endif
184 }
185 
186 /*
187  * Destroy a shared client record
188  */
189 static void nfs_free_client(struct nfs_client *clp)
190 {
191 	dprintk("--> nfs_free_client(%d)\n", clp->cl_nfsversion);
192 
193 	nfs4_shutdown_client(clp);
194 
195 	/* -EIO all pending I/O */
196 	if (!IS_ERR(clp->cl_rpcclient))
197 		rpc_shutdown_client(clp->cl_rpcclient);
198 
199 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
200 		nfs_callback_down();
201 
202 	if (__test_and_clear_bit(NFS_CS_RPCIOD, &clp->cl_res_state))
203 		rpciod_down();
204 
205 	kfree(clp->cl_hostname);
206 	kfree(clp);
207 
208 	dprintk("<-- nfs_free_client()\n");
209 }
210 
211 /*
212  * Release a reference to a shared client record
213  */
214 void nfs_put_client(struct nfs_client *clp)
215 {
216 	if (!clp)
217 		return;
218 
219 	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
220 
221 	if (atomic_dec_and_lock(&clp->cl_count, &nfs_client_lock)) {
222 		list_del(&clp->cl_share_link);
223 		spin_unlock(&nfs_client_lock);
224 
225 		BUG_ON(!list_empty(&clp->cl_superblocks));
226 
227 		nfs_free_client(clp);
228 	}
229 }
230 
231 /*
232  * Find a client by address
233  * - caller must hold nfs_client_lock
234  */
235 static struct nfs_client *__nfs_find_client(const struct sockaddr_in *addr, int nfsversion, int match_port)
236 {
237 	struct nfs_client *clp;
238 
239 	list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
240 		/* Don't match clients that failed to initialise properly */
241 		if (clp->cl_cons_state < 0)
242 			continue;
243 
244 		/* Different NFS versions cannot share the same nfs_client */
245 		if (clp->cl_nfsversion != nfsversion)
246 			continue;
247 
248 		if (memcmp(&clp->cl_addr.sin_addr, &addr->sin_addr,
249 			   sizeof(clp->cl_addr.sin_addr)) != 0)
250 			continue;
251 
252 		if (!match_port || clp->cl_addr.sin_port == addr->sin_port)
253 			goto found;
254 	}
255 
256 	return NULL;
257 
258 found:
259 	atomic_inc(&clp->cl_count);
260 	return clp;
261 }
262 
263 /*
264  * Find a client by IP address and protocol version
265  * - returns NULL if no such client
266  */
267 struct nfs_client *nfs_find_client(const struct sockaddr_in *addr, int nfsversion)
268 {
269 	struct nfs_client *clp;
270 
271 	spin_lock(&nfs_client_lock);
272 	clp = __nfs_find_client(addr, nfsversion, 0);
273 	spin_unlock(&nfs_client_lock);
274 	if (clp != NULL && clp->cl_cons_state != NFS_CS_READY) {
275 		nfs_put_client(clp);
276 		clp = NULL;
277 	}
278 	return clp;
279 }
280 
281 /*
282  * Look up a client by IP address and protocol version
283  * - creates a new record if one doesn't yet exist
284  */
285 static struct nfs_client *nfs_get_client(const char *hostname,
286 					 const struct sockaddr_in *addr,
287 					 int nfsversion)
288 {
289 	struct nfs_client *clp, *new = NULL;
290 	int error;
291 
292 	dprintk("--> nfs_get_client(%s,"NIPQUAD_FMT":%d,%d)\n",
293 		hostname ?: "", NIPQUAD(addr->sin_addr),
294 		addr->sin_port, nfsversion);
295 
296 	/* see if the client already exists */
297 	do {
298 		spin_lock(&nfs_client_lock);
299 
300 		clp = __nfs_find_client(addr, nfsversion, 1);
301 		if (clp)
302 			goto found_client;
303 		if (new)
304 			goto install_client;
305 
306 		spin_unlock(&nfs_client_lock);
307 
308 		new = nfs_alloc_client(hostname, addr, nfsversion);
309 	} while (new);
310 
311 	return ERR_PTR(-ENOMEM);
312 
313 	/* install a new client and return with it unready */
314 install_client:
315 	clp = new;
316 	list_add(&clp->cl_share_link, &nfs_client_list);
317 	spin_unlock(&nfs_client_lock);
318 	dprintk("--> nfs_get_client() = %p [new]\n", clp);
319 	return clp;
320 
321 	/* found an existing client
322 	 * - make sure it's ready before returning
323 	 */
324 found_client:
325 	spin_unlock(&nfs_client_lock);
326 
327 	if (new)
328 		nfs_free_client(new);
329 
330 	error = wait_event_interruptible(nfs_client_active_wq,
331 				clp->cl_cons_state != NFS_CS_INITING);
332 	if (error < 0) {
333 		nfs_put_client(clp);
334 		return ERR_PTR(-ERESTARTSYS);
335 	}
336 
337 	if (clp->cl_cons_state < NFS_CS_READY) {
338 		error = clp->cl_cons_state;
339 		nfs_put_client(clp);
340 		return ERR_PTR(error);
341 	}
342 
343 	BUG_ON(clp->cl_cons_state != NFS_CS_READY);
344 
345 	dprintk("--> nfs_get_client() = %p [share]\n", clp);
346 	return clp;
347 }
348 
349 /*
350  * Mark a server as ready or failed
351  */
352 static void nfs_mark_client_ready(struct nfs_client *clp, int state)
353 {
354 	clp->cl_cons_state = state;
355 	wake_up_all(&nfs_client_active_wq);
356 }
357 
358 /*
359  * Initialise the timeout values for a connection
360  */
361 static void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
362 				    unsigned int timeo, unsigned int retrans)
363 {
364 	to->to_initval = timeo * HZ / 10;
365 	to->to_retries = retrans;
366 	if (!to->to_retries)
367 		to->to_retries = 2;
368 
369 	switch (proto) {
370 	case IPPROTO_TCP:
371 		if (!to->to_initval)
372 			to->to_initval = 60 * HZ;
373 		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
374 			to->to_initval = NFS_MAX_TCP_TIMEOUT;
375 		to->to_increment = to->to_initval;
376 		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
377 		to->to_exponential = 0;
378 		break;
379 	case IPPROTO_UDP:
380 	default:
381 		if (!to->to_initval)
382 			to->to_initval = 11 * HZ / 10;
383 		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
384 			to->to_initval = NFS_MAX_UDP_TIMEOUT;
385 		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
386 		to->to_exponential = 1;
387 		break;
388 	}
389 }
390 
391 /*
392  * Create an RPC client handle
393  */
394 static int nfs_create_rpc_client(struct nfs_client *clp, int proto,
395 						unsigned int timeo,
396 						unsigned int retrans,
397 						rpc_authflavor_t flavor,
398 						int flags)
399 {
400 	struct rpc_timeout	timeparms;
401 	struct rpc_clnt		*clnt = NULL;
402 	struct rpc_create_args args = {
403 		.protocol	= proto,
404 		.address	= (struct sockaddr *)&clp->cl_addr,
405 		.addrsize	= sizeof(clp->cl_addr),
406 		.timeout	= &timeparms,
407 		.servername	= clp->cl_hostname,
408 		.program	= &nfs_program,
409 		.version	= clp->rpc_ops->version,
410 		.authflavor	= flavor,
411 		.flags		= flags,
412 	};
413 
414 	if (!IS_ERR(clp->cl_rpcclient))
415 		return 0;
416 
417 	nfs_init_timeout_values(&timeparms, proto, timeo, retrans);
418 	clp->retrans_timeo = timeparms.to_initval;
419 	clp->retrans_count = timeparms.to_retries;
420 
421 	clnt = rpc_create(&args);
422 	if (IS_ERR(clnt)) {
423 		dprintk("%s: cannot create RPC client. Error = %ld\n",
424 				__FUNCTION__, PTR_ERR(clnt));
425 		return PTR_ERR(clnt);
426 	}
427 
428 	clp->cl_rpcclient = clnt;
429 	return 0;
430 }
431 
432 /*
433  * Version 2 or 3 client destruction
434  */
435 static void nfs_destroy_server(struct nfs_server *server)
436 {
437 	if (!IS_ERR(server->client_acl))
438 		rpc_shutdown_client(server->client_acl);
439 
440 	if (!(server->flags & NFS_MOUNT_NONLM))
441 		lockd_down();	/* release rpc.lockd */
442 }
443 
444 /*
445  * Version 2 or 3 lockd setup
446  */
447 static int nfs_start_lockd(struct nfs_server *server)
448 {
449 	int error = 0;
450 
451 	if (server->nfs_client->cl_nfsversion > 3)
452 		goto out;
453 	if (server->flags & NFS_MOUNT_NONLM)
454 		goto out;
455 	error = lockd_up((server->flags & NFS_MOUNT_TCP) ?
456 			IPPROTO_TCP : IPPROTO_UDP);
457 	if (error < 0)
458 		server->flags |= NFS_MOUNT_NONLM;
459 	else
460 		server->destroy = nfs_destroy_server;
461 out:
462 	return error;
463 }
464 
465 /*
466  * Initialise an NFSv3 ACL client connection
467  */
468 #ifdef CONFIG_NFS_V3_ACL
469 static void nfs_init_server_aclclient(struct nfs_server *server)
470 {
471 	if (server->nfs_client->cl_nfsversion != 3)
472 		goto out_noacl;
473 	if (server->flags & NFS_MOUNT_NOACL)
474 		goto out_noacl;
475 
476 	server->client_acl = rpc_bind_new_program(server->client, &nfsacl_program, 3);
477 	if (IS_ERR(server->client_acl))
478 		goto out_noacl;
479 
480 	/* No errors! Assume that Sun nfsacls are supported */
481 	server->caps |= NFS_CAP_ACLS;
482 	return;
483 
484 out_noacl:
485 	server->caps &= ~NFS_CAP_ACLS;
486 }
487 #else
488 static inline void nfs_init_server_aclclient(struct nfs_server *server)
489 {
490 	server->flags &= ~NFS_MOUNT_NOACL;
491 	server->caps &= ~NFS_CAP_ACLS;
492 }
493 #endif
494 
495 /*
496  * Create a general RPC client
497  */
498 static int nfs_init_server_rpcclient(struct nfs_server *server, rpc_authflavor_t pseudoflavour)
499 {
500 	struct nfs_client *clp = server->nfs_client;
501 
502 	server->client = rpc_clone_client(clp->cl_rpcclient);
503 	if (IS_ERR(server->client)) {
504 		dprintk("%s: couldn't create rpc_client!\n", __FUNCTION__);
505 		return PTR_ERR(server->client);
506 	}
507 
508 	if (pseudoflavour != clp->cl_rpcclient->cl_auth->au_flavor) {
509 		struct rpc_auth *auth;
510 
511 		auth = rpcauth_create(pseudoflavour, server->client);
512 		if (IS_ERR(auth)) {
513 			dprintk("%s: couldn't create credcache!\n", __FUNCTION__);
514 			return PTR_ERR(auth);
515 		}
516 	}
517 	server->client->cl_softrtry = 0;
518 	if (server->flags & NFS_MOUNT_SOFT)
519 		server->client->cl_softrtry = 1;
520 
521 	server->client->cl_intr = 0;
522 	if (server->flags & NFS4_MOUNT_INTR)
523 		server->client->cl_intr = 1;
524 
525 	return 0;
526 }
527 
528 /*
529  * Initialise an NFS2 or NFS3 client
530  */
531 static int nfs_init_client(struct nfs_client *clp, const struct nfs_mount_data *data)
532 {
533 	int proto = (data->flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
534 	int error;
535 
536 	if (clp->cl_cons_state == NFS_CS_READY) {
537 		/* the client is already initialised */
538 		dprintk("<-- nfs_init_client() = 0 [already %p]\n", clp);
539 		return 0;
540 	}
541 
542 	/* Check NFS protocol revision and initialize RPC op vector */
543 	clp->rpc_ops = &nfs_v2_clientops;
544 #ifdef CONFIG_NFS_V3
545 	if (clp->cl_nfsversion == 3)
546 		clp->rpc_ops = &nfs_v3_clientops;
547 #endif
548 	/*
549 	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
550 	 * - RFC 2623, sec 2.3.2
551 	 */
552 	error = nfs_create_rpc_client(clp, proto, data->timeo, data->retrans,
553 					RPC_AUTH_UNIX, 0);
554 	if (error < 0)
555 		goto error;
556 	nfs_mark_client_ready(clp, NFS_CS_READY);
557 	return 0;
558 
559 error:
560 	nfs_mark_client_ready(clp, error);
561 	dprintk("<-- nfs_init_client() = xerror %d\n", error);
562 	return error;
563 }
564 
565 /*
566  * Create a version 2 or 3 client
567  */
568 static int nfs_init_server(struct nfs_server *server, const struct nfs_mount_data *data)
569 {
570 	struct nfs_client *clp;
571 	int error, nfsvers = 2;
572 
573 	dprintk("--> nfs_init_server()\n");
574 
575 #ifdef CONFIG_NFS_V3
576 	if (data->flags & NFS_MOUNT_VER3)
577 		nfsvers = 3;
578 #endif
579 
580 	/* Allocate or find a client reference we can use */
581 	clp = nfs_get_client(data->hostname, &data->addr, nfsvers);
582 	if (IS_ERR(clp)) {
583 		dprintk("<-- nfs_init_server() = error %ld\n", PTR_ERR(clp));
584 		return PTR_ERR(clp);
585 	}
586 
587 	error = nfs_init_client(clp, data);
588 	if (error < 0)
589 		goto error;
590 
591 	server->nfs_client = clp;
592 
593 	/* Initialise the client representation from the mount data */
594 	server->flags = data->flags & NFS_MOUNT_FLAGMASK;
595 
596 	if (data->rsize)
597 		server->rsize = nfs_block_size(data->rsize, NULL);
598 	if (data->wsize)
599 		server->wsize = nfs_block_size(data->wsize, NULL);
600 
601 	server->acregmin = data->acregmin * HZ;
602 	server->acregmax = data->acregmax * HZ;
603 	server->acdirmin = data->acdirmin * HZ;
604 	server->acdirmax = data->acdirmax * HZ;
605 
606 	/* Start lockd here, before we might error out */
607 	error = nfs_start_lockd(server);
608 	if (error < 0)
609 		goto error;
610 
611 	error = nfs_init_server_rpcclient(server, data->pseudoflavor);
612 	if (error < 0)
613 		goto error;
614 
615 	server->namelen  = data->namlen;
616 	/* Create a client RPC handle for the NFSv3 ACL management interface */
617 	nfs_init_server_aclclient(server);
618 	if (clp->cl_nfsversion == 3) {
619 		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
620 			server->namelen = NFS3_MAXNAMLEN;
621 		server->caps |= NFS_CAP_READDIRPLUS;
622 	} else {
623 		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
624 			server->namelen = NFS2_MAXNAMLEN;
625 	}
626 
627 	dprintk("<-- nfs_init_server() = 0 [new %p]\n", clp);
628 	return 0;
629 
630 error:
631 	server->nfs_client = NULL;
632 	nfs_put_client(clp);
633 	dprintk("<-- nfs_init_server() = xerror %d\n", error);
634 	return error;
635 }
636 
637 /*
638  * Load up the server record from information gained in an fsinfo record
639  */
640 static void nfs_server_set_fsinfo(struct nfs_server *server, struct nfs_fsinfo *fsinfo)
641 {
642 	unsigned long max_rpc_payload;
643 
644 	/* Work out a lot of parameters */
645 	if (server->rsize == 0)
646 		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
647 	if (server->wsize == 0)
648 		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
649 
650 	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
651 		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
652 	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
653 		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
654 
655 	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
656 	if (server->rsize > max_rpc_payload)
657 		server->rsize = max_rpc_payload;
658 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
659 		server->rsize = NFS_MAX_FILE_IO_SIZE;
660 	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
661 	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
662 
663 	if (server->wsize > max_rpc_payload)
664 		server->wsize = max_rpc_payload;
665 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
666 		server->wsize = NFS_MAX_FILE_IO_SIZE;
667 	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
668 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
669 
670 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
671 	if (server->dtsize > PAGE_CACHE_SIZE)
672 		server->dtsize = PAGE_CACHE_SIZE;
673 	if (server->dtsize > server->rsize)
674 		server->dtsize = server->rsize;
675 
676 	if (server->flags & NFS_MOUNT_NOAC) {
677 		server->acregmin = server->acregmax = 0;
678 		server->acdirmin = server->acdirmax = 0;
679 	}
680 
681 	server->maxfilesize = fsinfo->maxfilesize;
682 
683 	/* We're airborne Set socket buffersize */
684 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
685 }
686 
687 /*
688  * Probe filesystem information, including the FSID on v2/v3
689  */
690 static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
691 {
692 	struct nfs_fsinfo fsinfo;
693 	struct nfs_client *clp = server->nfs_client;
694 	int error;
695 
696 	dprintk("--> nfs_probe_fsinfo()\n");
697 
698 	if (clp->rpc_ops->set_capabilities != NULL) {
699 		error = clp->rpc_ops->set_capabilities(server, mntfh);
700 		if (error < 0)
701 			goto out_error;
702 	}
703 
704 	fsinfo.fattr = fattr;
705 	nfs_fattr_init(fattr);
706 	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
707 	if (error < 0)
708 		goto out_error;
709 
710 	nfs_server_set_fsinfo(server, &fsinfo);
711 
712 	/* Get some general file system info */
713 	if (server->namelen == 0) {
714 		struct nfs_pathconf pathinfo;
715 
716 		pathinfo.fattr = fattr;
717 		nfs_fattr_init(fattr);
718 
719 		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
720 			server->namelen = pathinfo.max_namelen;
721 	}
722 
723 	dprintk("<-- nfs_probe_fsinfo() = 0\n");
724 	return 0;
725 
726 out_error:
727 	dprintk("nfs_probe_fsinfo: error = %d\n", -error);
728 	return error;
729 }
730 
731 /*
732  * Copy useful information when duplicating a server record
733  */
734 static void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
735 {
736 	target->flags = source->flags;
737 	target->acregmin = source->acregmin;
738 	target->acregmax = source->acregmax;
739 	target->acdirmin = source->acdirmin;
740 	target->acdirmax = source->acdirmax;
741 	target->caps = source->caps;
742 }
743 
744 /*
745  * Allocate and initialise a server record
746  */
747 static struct nfs_server *nfs_alloc_server(void)
748 {
749 	struct nfs_server *server;
750 
751 	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
752 	if (!server)
753 		return NULL;
754 
755 	server->client = server->client_acl = ERR_PTR(-EINVAL);
756 
757 	/* Zero out the NFS state stuff */
758 	INIT_LIST_HEAD(&server->client_link);
759 	INIT_LIST_HEAD(&server->master_link);
760 
761 	server->io_stats = nfs_alloc_iostats();
762 	if (!server->io_stats) {
763 		kfree(server);
764 		return NULL;
765 	}
766 
767 	return server;
768 }
769 
770 /*
771  * Free up a server record
772  */
773 void nfs_free_server(struct nfs_server *server)
774 {
775 	dprintk("--> nfs_free_server()\n");
776 
777 	spin_lock(&nfs_client_lock);
778 	list_del(&server->client_link);
779 	list_del(&server->master_link);
780 	spin_unlock(&nfs_client_lock);
781 
782 	if (server->destroy != NULL)
783 		server->destroy(server);
784 	if (!IS_ERR(server->client))
785 		rpc_shutdown_client(server->client);
786 
787 	nfs_put_client(server->nfs_client);
788 
789 	nfs_free_iostats(server->io_stats);
790 	kfree(server);
791 	nfs_release_automount_timer();
792 	dprintk("<-- nfs_free_server()\n");
793 }
794 
795 /*
796  * Create a version 2 or 3 volume record
797  * - keyed on server and FSID
798  */
799 struct nfs_server *nfs_create_server(const struct nfs_mount_data *data,
800 				     struct nfs_fh *mntfh)
801 {
802 	struct nfs_server *server;
803 	struct nfs_fattr fattr;
804 	int error;
805 
806 	server = nfs_alloc_server();
807 	if (!server)
808 		return ERR_PTR(-ENOMEM);
809 
810 	/* Get a client representation */
811 	error = nfs_init_server(server, data);
812 	if (error < 0)
813 		goto error;
814 
815 	BUG_ON(!server->nfs_client);
816 	BUG_ON(!server->nfs_client->rpc_ops);
817 	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
818 
819 	/* Probe the root fh to retrieve its FSID */
820 	error = nfs_probe_fsinfo(server, mntfh, &fattr);
821 	if (error < 0)
822 		goto error;
823 	if (!(fattr.valid & NFS_ATTR_FATTR)) {
824 		error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr);
825 		if (error < 0) {
826 			dprintk("nfs_create_server: getattr error = %d\n", -error);
827 			goto error;
828 		}
829 	}
830 	memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid));
831 
832 	dprintk("Server FSID: %llx:%llx\n",
833 		(unsigned long long) server->fsid.major,
834 		(unsigned long long) server->fsid.minor);
835 
836 	BUG_ON(!server->nfs_client);
837 	BUG_ON(!server->nfs_client->rpc_ops);
838 	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
839 
840 	spin_lock(&nfs_client_lock);
841 	list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
842 	list_add_tail(&server->master_link, &nfs_volume_list);
843 	spin_unlock(&nfs_client_lock);
844 
845 	server->mount_time = jiffies;
846 	return server;
847 
848 error:
849 	nfs_free_server(server);
850 	return ERR_PTR(error);
851 }
852 
853 #ifdef CONFIG_NFS_V4
854 /*
855  * Initialise an NFS4 client record
856  */
857 static int nfs4_init_client(struct nfs_client *clp,
858 		int proto, int timeo, int retrans,
859 		const char *ip_addr,
860 		rpc_authflavor_t authflavour)
861 {
862 	int error;
863 
864 	if (clp->cl_cons_state == NFS_CS_READY) {
865 		/* the client is initialised already */
866 		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
867 		return 0;
868 	}
869 
870 	/* Check NFS protocol revision and initialize RPC op vector */
871 	clp->rpc_ops = &nfs_v4_clientops;
872 
873 	error = nfs_create_rpc_client(clp, proto, timeo, retrans, authflavour,
874 					RPC_CLNT_CREATE_DISCRTRY);
875 	if (error < 0)
876 		goto error;
877 	memcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
878 
879 	error = nfs_idmap_new(clp);
880 	if (error < 0) {
881 		dprintk("%s: failed to create idmapper. Error = %d\n",
882 			__FUNCTION__, error);
883 		goto error;
884 	}
885 	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
886 
887 	nfs_mark_client_ready(clp, NFS_CS_READY);
888 	return 0;
889 
890 error:
891 	nfs_mark_client_ready(clp, error);
892 	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
893 	return error;
894 }
895 
896 /*
897  * Set up an NFS4 client
898  */
899 static int nfs4_set_client(struct nfs_server *server,
900 		const char *hostname, const struct sockaddr_in *addr,
901 		const char *ip_addr,
902 		rpc_authflavor_t authflavour,
903 		int proto, int timeo, int retrans)
904 {
905 	struct nfs_client *clp;
906 	int error;
907 
908 	dprintk("--> nfs4_set_client()\n");
909 
910 	/* Allocate or find a client reference we can use */
911 	clp = nfs_get_client(hostname, addr, 4);
912 	if (IS_ERR(clp)) {
913 		error = PTR_ERR(clp);
914 		goto error;
915 	}
916 	error = nfs4_init_client(clp, proto, timeo, retrans, ip_addr, authflavour);
917 	if (error < 0)
918 		goto error_put;
919 
920 	server->nfs_client = clp;
921 	dprintk("<-- nfs4_set_client() = 0 [new %p]\n", clp);
922 	return 0;
923 
924 error_put:
925 	nfs_put_client(clp);
926 error:
927 	dprintk("<-- nfs4_set_client() = xerror %d\n", error);
928 	return error;
929 }
930 
931 /*
932  * Create a version 4 volume record
933  */
934 static int nfs4_init_server(struct nfs_server *server,
935 		const struct nfs4_mount_data *data, rpc_authflavor_t authflavour)
936 {
937 	int error;
938 
939 	dprintk("--> nfs4_init_server()\n");
940 
941 	/* Initialise the client representation from the mount data */
942 	server->flags = data->flags & NFS_MOUNT_FLAGMASK;
943 	server->caps |= NFS_CAP_ATOMIC_OPEN;
944 
945 	if (data->rsize)
946 		server->rsize = nfs_block_size(data->rsize, NULL);
947 	if (data->wsize)
948 		server->wsize = nfs_block_size(data->wsize, NULL);
949 
950 	server->acregmin = data->acregmin * HZ;
951 	server->acregmax = data->acregmax * HZ;
952 	server->acdirmin = data->acdirmin * HZ;
953 	server->acdirmax = data->acdirmax * HZ;
954 
955 	error = nfs_init_server_rpcclient(server, authflavour);
956 
957 	/* Done */
958 	dprintk("<-- nfs4_init_server() = %d\n", error);
959 	return error;
960 }
961 
962 /*
963  * Create a version 4 volume record
964  * - keyed on server and FSID
965  */
966 struct nfs_server *nfs4_create_server(const struct nfs4_mount_data *data,
967 				      const char *hostname,
968 				      const struct sockaddr_in *addr,
969 				      const char *mntpath,
970 				      const char *ip_addr,
971 				      rpc_authflavor_t authflavour,
972 				      struct nfs_fh *mntfh)
973 {
974 	struct nfs_fattr fattr;
975 	struct nfs_server *server;
976 	int error;
977 
978 	dprintk("--> nfs4_create_server()\n");
979 
980 	server = nfs_alloc_server();
981 	if (!server)
982 		return ERR_PTR(-ENOMEM);
983 
984 	/* Get a client record */
985 	error = nfs4_set_client(server, hostname, addr, ip_addr, authflavour,
986 			data->proto, data->timeo, data->retrans);
987 	if (error < 0)
988 		goto error;
989 
990 	/* set up the general RPC client */
991 	error = nfs4_init_server(server, data, authflavour);
992 	if (error < 0)
993 		goto error;
994 
995 	BUG_ON(!server->nfs_client);
996 	BUG_ON(!server->nfs_client->rpc_ops);
997 	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
998 
999 	/* Probe the root fh to retrieve its FSID */
1000 	error = nfs4_path_walk(server, mntfh, mntpath);
1001 	if (error < 0)
1002 		goto error;
1003 
1004 	dprintk("Server FSID: %llx:%llx\n",
1005 		(unsigned long long) server->fsid.major,
1006 		(unsigned long long) server->fsid.minor);
1007 	dprintk("Mount FH: %d\n", mntfh->size);
1008 
1009 	error = nfs_probe_fsinfo(server, mntfh, &fattr);
1010 	if (error < 0)
1011 		goto error;
1012 
1013 	BUG_ON(!server->nfs_client);
1014 	BUG_ON(!server->nfs_client->rpc_ops);
1015 	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
1016 
1017 	spin_lock(&nfs_client_lock);
1018 	list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
1019 	list_add_tail(&server->master_link, &nfs_volume_list);
1020 	spin_unlock(&nfs_client_lock);
1021 
1022 	server->mount_time = jiffies;
1023 	dprintk("<-- nfs4_create_server() = %p\n", server);
1024 	return server;
1025 
1026 error:
1027 	nfs_free_server(server);
1028 	dprintk("<-- nfs4_create_server() = error %d\n", error);
1029 	return ERR_PTR(error);
1030 }
1031 
1032 /*
1033  * Create an NFS4 referral server record
1034  */
1035 struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
1036 					       struct nfs_fh *mntfh)
1037 {
1038 	struct nfs_client *parent_client;
1039 	struct nfs_server *server, *parent_server;
1040 	struct nfs_fattr fattr;
1041 	int error;
1042 
1043 	dprintk("--> nfs4_create_referral_server()\n");
1044 
1045 	server = nfs_alloc_server();
1046 	if (!server)
1047 		return ERR_PTR(-ENOMEM);
1048 
1049 	parent_server = NFS_SB(data->sb);
1050 	parent_client = parent_server->nfs_client;
1051 
1052 	/* Get a client representation.
1053 	 * Note: NFSv4 always uses TCP, */
1054 	error = nfs4_set_client(server, data->hostname, data->addr,
1055 			parent_client->cl_ipaddr,
1056 			data->authflavor,
1057 			parent_server->client->cl_xprt->prot,
1058 			parent_client->retrans_timeo,
1059 			parent_client->retrans_count);
1060 	if (error < 0)
1061 		goto error;
1062 
1063 	/* Initialise the client representation from the parent server */
1064 	nfs_server_copy_userdata(server, parent_server);
1065 	server->caps |= NFS_CAP_ATOMIC_OPEN;
1066 
1067 	error = nfs_init_server_rpcclient(server, data->authflavor);
1068 	if (error < 0)
1069 		goto error;
1070 
1071 	BUG_ON(!server->nfs_client);
1072 	BUG_ON(!server->nfs_client->rpc_ops);
1073 	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
1074 
1075 	/* Probe the root fh to retrieve its FSID and filehandle */
1076 	error = nfs4_path_walk(server, mntfh, data->mnt_path);
1077 	if (error < 0)
1078 		goto error;
1079 
1080 	/* probe the filesystem info for this server filesystem */
1081 	error = nfs_probe_fsinfo(server, mntfh, &fattr);
1082 	if (error < 0)
1083 		goto error;
1084 
1085 	dprintk("Referral FSID: %llx:%llx\n",
1086 		(unsigned long long) server->fsid.major,
1087 		(unsigned long long) server->fsid.minor);
1088 
1089 	spin_lock(&nfs_client_lock);
1090 	list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
1091 	list_add_tail(&server->master_link, &nfs_volume_list);
1092 	spin_unlock(&nfs_client_lock);
1093 
1094 	server->mount_time = jiffies;
1095 
1096 	dprintk("<-- nfs_create_referral_server() = %p\n", server);
1097 	return server;
1098 
1099 error:
1100 	nfs_free_server(server);
1101 	dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
1102 	return ERR_PTR(error);
1103 }
1104 
1105 #endif /* CONFIG_NFS_V4 */
1106 
1107 /*
1108  * Clone an NFS2, NFS3 or NFS4 server record
1109  */
1110 struct nfs_server *nfs_clone_server(struct nfs_server *source,
1111 				    struct nfs_fh *fh,
1112 				    struct nfs_fattr *fattr)
1113 {
1114 	struct nfs_server *server;
1115 	struct nfs_fattr fattr_fsinfo;
1116 	int error;
1117 
1118 	dprintk("--> nfs_clone_server(,%llx:%llx,)\n",
1119 		(unsigned long long) fattr->fsid.major,
1120 		(unsigned long long) fattr->fsid.minor);
1121 
1122 	server = nfs_alloc_server();
1123 	if (!server)
1124 		return ERR_PTR(-ENOMEM);
1125 
1126 	/* Copy data from the source */
1127 	server->nfs_client = source->nfs_client;
1128 	atomic_inc(&server->nfs_client->cl_count);
1129 	nfs_server_copy_userdata(server, source);
1130 
1131 	server->fsid = fattr->fsid;
1132 
1133 	error = nfs_init_server_rpcclient(server, source->client->cl_auth->au_flavor);
1134 	if (error < 0)
1135 		goto out_free_server;
1136 	if (!IS_ERR(source->client_acl))
1137 		nfs_init_server_aclclient(server);
1138 
1139 	/* probe the filesystem info for this server filesystem */
1140 	error = nfs_probe_fsinfo(server, fh, &fattr_fsinfo);
1141 	if (error < 0)
1142 		goto out_free_server;
1143 
1144 	dprintk("Cloned FSID: %llx:%llx\n",
1145 		(unsigned long long) server->fsid.major,
1146 		(unsigned long long) server->fsid.minor);
1147 
1148 	error = nfs_start_lockd(server);
1149 	if (error < 0)
1150 		goto out_free_server;
1151 
1152 	spin_lock(&nfs_client_lock);
1153 	list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
1154 	list_add_tail(&server->master_link, &nfs_volume_list);
1155 	spin_unlock(&nfs_client_lock);
1156 
1157 	server->mount_time = jiffies;
1158 
1159 	dprintk("<-- nfs_clone_server() = %p\n", server);
1160 	return server;
1161 
1162 out_free_server:
1163 	nfs_free_server(server);
1164 	dprintk("<-- nfs_clone_server() = error %d\n", error);
1165 	return ERR_PTR(error);
1166 }
1167 
1168 #ifdef CONFIG_PROC_FS
1169 static struct proc_dir_entry *proc_fs_nfs;
1170 
1171 static int nfs_server_list_open(struct inode *inode, struct file *file);
1172 static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
1173 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
1174 static void nfs_server_list_stop(struct seq_file *p, void *v);
1175 static int nfs_server_list_show(struct seq_file *m, void *v);
1176 
1177 static struct seq_operations nfs_server_list_ops = {
1178 	.start	= nfs_server_list_start,
1179 	.next	= nfs_server_list_next,
1180 	.stop	= nfs_server_list_stop,
1181 	.show	= nfs_server_list_show,
1182 };
1183 
1184 static const struct file_operations nfs_server_list_fops = {
1185 	.open		= nfs_server_list_open,
1186 	.read		= seq_read,
1187 	.llseek		= seq_lseek,
1188 	.release	= seq_release,
1189 };
1190 
1191 static int nfs_volume_list_open(struct inode *inode, struct file *file);
1192 static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
1193 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
1194 static void nfs_volume_list_stop(struct seq_file *p, void *v);
1195 static int nfs_volume_list_show(struct seq_file *m, void *v);
1196 
1197 static struct seq_operations nfs_volume_list_ops = {
1198 	.start	= nfs_volume_list_start,
1199 	.next	= nfs_volume_list_next,
1200 	.stop	= nfs_volume_list_stop,
1201 	.show	= nfs_volume_list_show,
1202 };
1203 
1204 static const struct file_operations nfs_volume_list_fops = {
1205 	.open		= nfs_volume_list_open,
1206 	.read		= seq_read,
1207 	.llseek		= seq_lseek,
1208 	.release	= seq_release,
1209 };
1210 
1211 /*
1212  * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
1213  * we're dealing
1214  */
1215 static int nfs_server_list_open(struct inode *inode, struct file *file)
1216 {
1217 	struct seq_file *m;
1218 	int ret;
1219 
1220 	ret = seq_open(file, &nfs_server_list_ops);
1221 	if (ret < 0)
1222 		return ret;
1223 
1224 	m = file->private_data;
1225 	m->private = PDE(inode)->data;
1226 
1227 	return 0;
1228 }
1229 
1230 /*
1231  * set up the iterator to start reading from the server list and return the first item
1232  */
1233 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
1234 {
1235 	struct list_head *_p;
1236 	loff_t pos = *_pos;
1237 
1238 	/* lock the list against modification */
1239 	spin_lock(&nfs_client_lock);
1240 
1241 	/* allow for the header line */
1242 	if (!pos)
1243 		return SEQ_START_TOKEN;
1244 	pos--;
1245 
1246 	/* find the n'th element in the list */
1247 	list_for_each(_p, &nfs_client_list)
1248 		if (!pos--)
1249 			break;
1250 
1251 	return _p != &nfs_client_list ? _p : NULL;
1252 }
1253 
1254 /*
1255  * move to next server
1256  */
1257 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
1258 {
1259 	struct list_head *_p;
1260 
1261 	(*pos)++;
1262 
1263 	_p = v;
1264 	_p = (v == SEQ_START_TOKEN) ? nfs_client_list.next : _p->next;
1265 
1266 	return _p != &nfs_client_list ? _p : NULL;
1267 }
1268 
1269 /*
1270  * clean up after reading from the transports list
1271  */
1272 static void nfs_server_list_stop(struct seq_file *p, void *v)
1273 {
1274 	spin_unlock(&nfs_client_lock);
1275 }
1276 
1277 /*
1278  * display a header line followed by a load of call lines
1279  */
1280 static int nfs_server_list_show(struct seq_file *m, void *v)
1281 {
1282 	struct nfs_client *clp;
1283 
1284 	/* display header on line 1 */
1285 	if (v == SEQ_START_TOKEN) {
1286 		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
1287 		return 0;
1288 	}
1289 
1290 	/* display one transport per line on subsequent lines */
1291 	clp = list_entry(v, struct nfs_client, cl_share_link);
1292 
1293 	seq_printf(m, "v%d %02x%02x%02x%02x %4hx %3d %s\n",
1294 		   clp->cl_nfsversion,
1295 		   NIPQUAD(clp->cl_addr.sin_addr),
1296 		   ntohs(clp->cl_addr.sin_port),
1297 		   atomic_read(&clp->cl_count),
1298 		   clp->cl_hostname);
1299 
1300 	return 0;
1301 }
1302 
1303 /*
1304  * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
1305  */
1306 static int nfs_volume_list_open(struct inode *inode, struct file *file)
1307 {
1308 	struct seq_file *m;
1309 	int ret;
1310 
1311 	ret = seq_open(file, &nfs_volume_list_ops);
1312 	if (ret < 0)
1313 		return ret;
1314 
1315 	m = file->private_data;
1316 	m->private = PDE(inode)->data;
1317 
1318 	return 0;
1319 }
1320 
1321 /*
1322  * set up the iterator to start reading from the volume list and return the first item
1323  */
1324 static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
1325 {
1326 	struct list_head *_p;
1327 	loff_t pos = *_pos;
1328 
1329 	/* lock the list against modification */
1330 	spin_lock(&nfs_client_lock);
1331 
1332 	/* allow for the header line */
1333 	if (!pos)
1334 		return SEQ_START_TOKEN;
1335 	pos--;
1336 
1337 	/* find the n'th element in the list */
1338 	list_for_each(_p, &nfs_volume_list)
1339 		if (!pos--)
1340 			break;
1341 
1342 	return _p != &nfs_volume_list ? _p : NULL;
1343 }
1344 
1345 /*
1346  * move to next volume
1347  */
1348 static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
1349 {
1350 	struct list_head *_p;
1351 
1352 	(*pos)++;
1353 
1354 	_p = v;
1355 	_p = (v == SEQ_START_TOKEN) ? nfs_volume_list.next : _p->next;
1356 
1357 	return _p != &nfs_volume_list ? _p : NULL;
1358 }
1359 
1360 /*
1361  * clean up after reading from the transports list
1362  */
1363 static void nfs_volume_list_stop(struct seq_file *p, void *v)
1364 {
1365 	spin_unlock(&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 
1377 	/* display header on line 1 */
1378 	if (v == SEQ_START_TOKEN) {
1379 		seq_puts(m, "NV SERVER   PORT DEV     FSID\n");
1380 		return 0;
1381 	}
1382 	/* display one transport per line on subsequent lines */
1383 	server = list_entry(v, struct nfs_server, master_link);
1384 	clp = server->nfs_client;
1385 
1386 	snprintf(dev, 8, "%u:%u",
1387 		 MAJOR(server->s_dev), MINOR(server->s_dev));
1388 
1389 	snprintf(fsid, 17, "%llx:%llx",
1390 		 (unsigned long long) server->fsid.major,
1391 		 (unsigned long long) server->fsid.minor);
1392 
1393 	seq_printf(m, "v%d %02x%02x%02x%02x %4hx %-7s %-17s\n",
1394 		   clp->cl_nfsversion,
1395 		   NIPQUAD(clp->cl_addr.sin_addr),
1396 		   ntohs(clp->cl_addr.sin_port),
1397 		   dev,
1398 		   fsid);
1399 
1400 	return 0;
1401 }
1402 
1403 /*
1404  * initialise the /proc/fs/nfsfs/ directory
1405  */
1406 int __init nfs_fs_proc_init(void)
1407 {
1408 	struct proc_dir_entry *p;
1409 
1410 	proc_fs_nfs = proc_mkdir("nfsfs", proc_root_fs);
1411 	if (!proc_fs_nfs)
1412 		goto error_0;
1413 
1414 	proc_fs_nfs->owner = THIS_MODULE;
1415 
1416 	/* a file of servers with which we're dealing */
1417 	p = create_proc_entry("servers", S_IFREG|S_IRUGO, proc_fs_nfs);
1418 	if (!p)
1419 		goto error_1;
1420 
1421 	p->proc_fops = &nfs_server_list_fops;
1422 	p->owner = THIS_MODULE;
1423 
1424 	/* a file of volumes that we have mounted */
1425 	p = create_proc_entry("volumes", S_IFREG|S_IRUGO, proc_fs_nfs);
1426 	if (!p)
1427 		goto error_2;
1428 
1429 	p->proc_fops = &nfs_volume_list_fops;
1430 	p->owner = THIS_MODULE;
1431 	return 0;
1432 
1433 error_2:
1434 	remove_proc_entry("servers", proc_fs_nfs);
1435 error_1:
1436 	remove_proc_entry("nfsfs", proc_root_fs);
1437 error_0:
1438 	return -ENOMEM;
1439 }
1440 
1441 /*
1442  * clean up the /proc/fs/nfsfs/ directory
1443  */
1444 void nfs_fs_proc_exit(void)
1445 {
1446 	remove_proc_entry("volumes", proc_fs_nfs);
1447 	remove_proc_entry("servers", proc_fs_nfs);
1448 	remove_proc_entry("nfsfs", proc_root_fs);
1449 }
1450 
1451 #endif /* CONFIG_PROC_FS */
1452