xref: /openbmc/linux/fs/nfs/nfs4client.c (revision 42c2c4249cd0192e29eec71e3e94d7bbc383c8de)
1 /*
2  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
3  * Written by David Howells (dhowells@redhat.com)
4  */
5 #include <linux/module.h>
6 #include <linux/nfs_fs.h>
7 #include <linux/nfs_idmap.h>
8 #include <linux/nfs_mount.h>
9 #include <linux/sunrpc/addr.h>
10 #include <linux/sunrpc/auth.h>
11 #include <linux/sunrpc/xprt.h>
12 #include <linux/sunrpc/bc_xprt.h>
13 #include "internal.h"
14 #include "callback.h"
15 #include "delegation.h"
16 #include "nfs4session.h"
17 #include "pnfs.h"
18 #include "netns.h"
19 
20 #define NFSDBG_FACILITY		NFSDBG_CLIENT
21 
22 /*
23  * Get a unique NFSv4.0 callback identifier which will be used
24  * by the V4.0 callback service to lookup the nfs_client struct
25  */
26 static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
27 {
28 	int ret = 0;
29 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
30 
31 	if (clp->rpc_ops->version != 4 || minorversion != 0)
32 		return ret;
33 	idr_preload(GFP_KERNEL);
34 	spin_lock(&nn->nfs_client_lock);
35 	ret = idr_alloc(&nn->cb_ident_idr, clp, 0, 0, GFP_NOWAIT);
36 	if (ret >= 0)
37 		clp->cl_cb_ident = ret;
38 	spin_unlock(&nn->nfs_client_lock);
39 	idr_preload_end();
40 	return ret < 0 ? ret : 0;
41 }
42 
43 #ifdef CONFIG_NFS_V4_1
44 static void nfs4_shutdown_session(struct nfs_client *clp)
45 {
46 	if (nfs4_has_session(clp)) {
47 		nfs4_destroy_session(clp->cl_session);
48 		nfs4_destroy_clientid(clp);
49 	}
50 
51 }
52 #else /* CONFIG_NFS_V4_1 */
53 static void nfs4_shutdown_session(struct nfs_client *clp)
54 {
55 }
56 #endif /* CONFIG_NFS_V4_1 */
57 
58 struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
59 {
60 	int err;
61 	struct nfs_client *clp = nfs_alloc_client(cl_init);
62 	if (IS_ERR(clp))
63 		return clp;
64 
65 	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
66 	if (err)
67 		goto error;
68 
69 	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
70 		err = -EINVAL;
71 		goto error;
72 	}
73 
74 	spin_lock_init(&clp->cl_lock);
75 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
76 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
77 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
78 	clp->cl_minorversion = cl_init->minorversion;
79 	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
80 	return clp;
81 
82 error:
83 	nfs_free_client(clp);
84 	return ERR_PTR(err);
85 }
86 
87 /*
88  * Destroy the NFS4 callback service
89  */
90 static void nfs4_destroy_callback(struct nfs_client *clp)
91 {
92 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
93 		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
94 }
95 
96 static void nfs4_shutdown_client(struct nfs_client *clp)
97 {
98 	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
99 		nfs4_kill_renewd(clp);
100 	nfs4_shutdown_session(clp);
101 	nfs4_destroy_callback(clp);
102 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
103 		nfs_idmap_delete(clp);
104 
105 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
106 	kfree(clp->cl_serverowner);
107 	kfree(clp->cl_serverscope);
108 	kfree(clp->cl_implid);
109 }
110 
111 void nfs4_free_client(struct nfs_client *clp)
112 {
113 	nfs4_shutdown_client(clp);
114 	nfs_free_client(clp);
115 }
116 
117 /*
118  * Initialize the NFS4 callback service
119  */
120 static int nfs4_init_callback(struct nfs_client *clp)
121 {
122 	int error;
123 
124 	if (clp->rpc_ops->version == 4) {
125 		struct rpc_xprt *xprt;
126 
127 		xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);
128 
129 		if (nfs4_has_session(clp)) {
130 			error = xprt_setup_backchannel(xprt,
131 						NFS41_BC_MIN_CALLBACKS);
132 			if (error < 0)
133 				return error;
134 		}
135 
136 		error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
137 		if (error < 0) {
138 			dprintk("%s: failed to start callback. Error = %d\n",
139 				__func__, error);
140 			return error;
141 		}
142 		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
143 	}
144 	return 0;
145 }
146 
147 /*
148  * Initialize the minor version specific parts of an NFS4 client record
149  */
150 static int nfs4_init_client_minor_version(struct nfs_client *clp)
151 {
152 #if defined(CONFIG_NFS_V4_1)
153 	if (clp->cl_mvops->minor_version) {
154 		struct nfs4_session *session = NULL;
155 		/*
156 		 * Create the session and mark it expired.
157 		 * When a SEQUENCE operation encounters the expired session
158 		 * it will do session recovery to initialize it.
159 		 */
160 		session = nfs4_alloc_session(clp);
161 		if (!session)
162 			return -ENOMEM;
163 
164 		clp->cl_session = session;
165 		/*
166 		 * The create session reply races with the server back
167 		 * channel probe. Mark the client NFS_CS_SESSION_INITING
168 		 * so that the client back channel can find the
169 		 * nfs_client struct
170 		 */
171 		nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
172 	}
173 #endif /* CONFIG_NFS_V4_1 */
174 
175 	return nfs4_init_callback(clp);
176 }
177 
178 /**
179  * nfs4_init_client - Initialise an NFS4 client record
180  *
181  * @clp: nfs_client to initialise
182  * @timeparms: timeout parameters for underlying RPC transport
183  * @ip_addr: callback IP address in presentation format
184  * @authflavor: authentication flavor for underlying RPC transport
185  *
186  * Returns pointer to an NFS client, or an ERR_PTR value.
187  */
188 struct nfs_client *nfs4_init_client(struct nfs_client *clp,
189 				    const struct rpc_timeout *timeparms,
190 				    const char *ip_addr,
191 				    rpc_authflavor_t authflavour)
192 {
193 	char buf[INET6_ADDRSTRLEN + 1];
194 	struct nfs_client *old;
195 	int error;
196 
197 	if (clp->cl_cons_state == NFS_CS_READY) {
198 		/* the client is initialised already */
199 		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
200 		return clp;
201 	}
202 
203 	/* Check NFS protocol revision and initialize RPC op vector */
204 	clp->rpc_ops = &nfs_v4_clientops;
205 
206 	if (clp->cl_minorversion != 0)
207 		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
208 	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
209 	error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_GSS_KRB5I);
210 	if (error == -EINVAL)
211 		error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_NULL);
212 	if (error < 0)
213 		goto error;
214 
215 	/* If no clientaddr= option was specified, find a usable cb address */
216 	if (ip_addr == NULL) {
217 		struct sockaddr_storage cb_addr;
218 		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
219 
220 		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
221 		if (error < 0)
222 			goto error;
223 		error = rpc_ntop(sap, buf, sizeof(buf));
224 		if (error < 0)
225 			goto error;
226 		ip_addr = (const char *)buf;
227 	}
228 	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
229 
230 	error = nfs_idmap_new(clp);
231 	if (error < 0) {
232 		dprintk("%s: failed to create idmapper. Error = %d\n",
233 			__func__, error);
234 		goto error;
235 	}
236 	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
237 
238 	error = nfs4_init_client_minor_version(clp);
239 	if (error < 0)
240 		goto error;
241 
242 	if (!nfs4_has_session(clp))
243 		nfs_mark_client_ready(clp, NFS_CS_READY);
244 
245 	error = nfs4_discover_server_trunking(clp, &old);
246 	if (error < 0)
247 		goto error;
248 	nfs_put_client(clp);
249 	if (clp != old) {
250 		clp->cl_preserve_clid = true;
251 		clp = old;
252 	}
253 
254 	return clp;
255 
256 error:
257 	nfs_mark_client_ready(clp, error);
258 	nfs_put_client(clp);
259 	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
260 	return ERR_PTR(error);
261 }
262 
263 /*
264  * SETCLIENTID just did a callback update with the callback ident in
265  * "drop," but server trunking discovery claims "drop" and "keep" are
266  * actually the same server.  Swap the callback IDs so that "keep"
267  * will continue to use the callback ident the server now knows about,
268  * and so that "keep"'s original callback ident is destroyed when
269  * "drop" is freed.
270  */
271 static void nfs4_swap_callback_idents(struct nfs_client *keep,
272 				      struct nfs_client *drop)
273 {
274 	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
275 	unsigned int save = keep->cl_cb_ident;
276 
277 	if (keep->cl_cb_ident == drop->cl_cb_ident)
278 		return;
279 
280 	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
281 		__func__, keep->cl_cb_ident, drop->cl_cb_ident);
282 
283 	spin_lock(&nn->nfs_client_lock);
284 
285 	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
286 	keep->cl_cb_ident = drop->cl_cb_ident;
287 
288 	idr_replace(&nn->cb_ident_idr, drop, save);
289 	drop->cl_cb_ident = save;
290 
291 	spin_unlock(&nn->nfs_client_lock);
292 }
293 
294 /**
295  * nfs40_walk_client_list - Find server that recognizes a client ID
296  *
297  * @new: nfs_client with client ID to test
298  * @result: OUT: found nfs_client, or new
299  * @cred: credential to use for trunking test
300  *
301  * Returns zero, a negative errno, or a negative NFS4ERR status.
302  * If zero is returned, an nfs_client pointer is planted in "result."
303  *
304  * NB: nfs40_walk_client_list() relies on the new nfs_client being
305  *     the last nfs_client on the list.
306  */
307 int nfs40_walk_client_list(struct nfs_client *new,
308 			   struct nfs_client **result,
309 			   struct rpc_cred *cred)
310 {
311 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
312 	struct nfs_client *pos, *prev = NULL;
313 	struct nfs4_setclientid_res clid = {
314 		.clientid	= new->cl_clientid,
315 		.confirm	= new->cl_confirm,
316 	};
317 	int status = -NFS4ERR_STALE_CLIENTID;
318 
319 	spin_lock(&nn->nfs_client_lock);
320 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
321 		/* If "pos" isn't marked ready, we can't trust the
322 		 * remaining fields in "pos" */
323 		if (pos->cl_cons_state > NFS_CS_READY) {
324 			atomic_inc(&pos->cl_count);
325 			spin_unlock(&nn->nfs_client_lock);
326 
327 			if (prev)
328 				nfs_put_client(prev);
329 			prev = pos;
330 
331 			status = nfs_wait_client_init_complete(pos);
332 			spin_lock(&nn->nfs_client_lock);
333 			if (status < 0)
334 				continue;
335 		}
336 		if (pos->cl_cons_state != NFS_CS_READY)
337 			continue;
338 
339 		if (pos->rpc_ops != new->rpc_ops)
340 			continue;
341 
342 		if (pos->cl_proto != new->cl_proto)
343 			continue;
344 
345 		if (pos->cl_minorversion != new->cl_minorversion)
346 			continue;
347 
348 		if (pos->cl_clientid != new->cl_clientid)
349 			continue;
350 
351 		atomic_inc(&pos->cl_count);
352 		spin_unlock(&nn->nfs_client_lock);
353 
354 		if (prev)
355 			nfs_put_client(prev);
356 		prev = pos;
357 
358 		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
359 		switch (status) {
360 		case -NFS4ERR_STALE_CLIENTID:
361 			break;
362 		case 0:
363 			nfs4_swap_callback_idents(pos, new);
364 
365 			prev = NULL;
366 			*result = pos;
367 			dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
368 				__func__, pos, atomic_read(&pos->cl_count));
369 		default:
370 			goto out;
371 		}
372 
373 		spin_lock(&nn->nfs_client_lock);
374 	}
375 	spin_unlock(&nn->nfs_client_lock);
376 
377 	/* No match found. The server lost our clientid */
378 out:
379 	if (prev)
380 		nfs_put_client(prev);
381 	dprintk("NFS: <-- %s status = %d\n", __func__, status);
382 	return status;
383 }
384 
385 #ifdef CONFIG_NFS_V4_1
386 /*
387  * Returns true if the client IDs match
388  */
389 static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
390 {
391 	if (a->cl_clientid != b->cl_clientid) {
392 		dprintk("NFS: --> %s client ID %llx does not match %llx\n",
393 			__func__, a->cl_clientid, b->cl_clientid);
394 		return false;
395 	}
396 	dprintk("NFS: --> %s client ID %llx matches %llx\n",
397 		__func__, a->cl_clientid, b->cl_clientid);
398 	return true;
399 }
400 
401 /*
402  * Returns true if the server owners match
403  */
404 static bool
405 nfs4_match_serverowners(struct nfs_client *a, struct nfs_client *b)
406 {
407 	struct nfs41_server_owner *o1 = a->cl_serverowner;
408 	struct nfs41_server_owner *o2 = b->cl_serverowner;
409 
410 	if (o1->minor_id != o2->minor_id) {
411 		dprintk("NFS: --> %s server owner minor IDs do not match\n",
412 			__func__);
413 		return false;
414 	}
415 
416 	if (o1->major_id_sz != o2->major_id_sz)
417 		goto out_major_mismatch;
418 	if (memcmp(o1->major_id, o2->major_id, o1->major_id_sz) != 0)
419 		goto out_major_mismatch;
420 
421 	dprintk("NFS: --> %s server owners match\n", __func__);
422 	return true;
423 
424 out_major_mismatch:
425 	dprintk("NFS: --> %s server owner major IDs do not match\n",
426 		__func__);
427 	return false;
428 }
429 
430 /**
431  * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
432  *
433  * @new: nfs_client with client ID to test
434  * @result: OUT: found nfs_client, or new
435  * @cred: credential to use for trunking test
436  *
437  * Returns zero, a negative errno, or a negative NFS4ERR status.
438  * If zero is returned, an nfs_client pointer is planted in "result."
439  *
440  * NB: nfs41_walk_client_list() relies on the new nfs_client being
441  *     the last nfs_client on the list.
442  */
443 int nfs41_walk_client_list(struct nfs_client *new,
444 			   struct nfs_client **result,
445 			   struct rpc_cred *cred)
446 {
447 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
448 	struct nfs_client *pos, *prev = NULL;
449 	int status = -NFS4ERR_STALE_CLIENTID;
450 
451 	spin_lock(&nn->nfs_client_lock);
452 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
453 		/* If "pos" isn't marked ready, we can't trust the
454 		 * remaining fields in "pos", especially the client
455 		 * ID and serverowner fields.  Wait for CREATE_SESSION
456 		 * to finish. */
457 		if (pos->cl_cons_state > NFS_CS_READY) {
458 			atomic_inc(&pos->cl_count);
459 			spin_unlock(&nn->nfs_client_lock);
460 
461 			if (prev)
462 				nfs_put_client(prev);
463 			prev = pos;
464 
465 			status = nfs_wait_client_init_complete(pos);
466 			if (status == 0) {
467 				nfs4_schedule_lease_recovery(pos);
468 				status = nfs4_wait_clnt_recover(pos);
469 			}
470 			spin_lock(&nn->nfs_client_lock);
471 			if (status < 0)
472 				continue;
473 		}
474 		if (pos->cl_cons_state != NFS_CS_READY)
475 			continue;
476 
477 		if (pos->rpc_ops != new->rpc_ops)
478 			continue;
479 
480 		if (pos->cl_proto != new->cl_proto)
481 			continue;
482 
483 		if (pos->cl_minorversion != new->cl_minorversion)
484 			continue;
485 
486 		if (!nfs4_match_clientids(pos, new))
487 			continue;
488 
489 		if (!nfs4_match_serverowners(pos, new))
490 			continue;
491 
492 		atomic_inc(&pos->cl_count);
493 		*result = pos;
494 		status = 0;
495 		dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
496 			__func__, pos, atomic_read(&pos->cl_count));
497 		break;
498 	}
499 
500 	/* No matching nfs_client found. */
501 	spin_unlock(&nn->nfs_client_lock);
502 	dprintk("NFS: <-- %s status = %d\n", __func__, status);
503 	if (prev)
504 		nfs_put_client(prev);
505 	return status;
506 }
507 #endif	/* CONFIG_NFS_V4_1 */
508 
509 static void nfs4_destroy_server(struct nfs_server *server)
510 {
511 	nfs_server_return_all_delegations(server);
512 	unset_pnfs_layoutdriver(server);
513 	nfs4_purge_state_owners(server);
514 }
515 
516 /*
517  * NFSv4.0 callback thread helper
518  *
519  * Find a client by callback identifier
520  */
521 struct nfs_client *
522 nfs4_find_client_ident(struct net *net, int cb_ident)
523 {
524 	struct nfs_client *clp;
525 	struct nfs_net *nn = net_generic(net, nfs_net_id);
526 
527 	spin_lock(&nn->nfs_client_lock);
528 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
529 	if (clp)
530 		atomic_inc(&clp->cl_count);
531 	spin_unlock(&nn->nfs_client_lock);
532 	return clp;
533 }
534 
535 #if defined(CONFIG_NFS_V4_1)
536 /* Common match routine for v4.0 and v4.1 callback services */
537 static bool nfs4_cb_match_client(const struct sockaddr *addr,
538 		struct nfs_client *clp, u32 minorversion)
539 {
540 	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
541 
542 	/* Don't match clients that failed to initialise */
543 	if (!(clp->cl_cons_state == NFS_CS_READY ||
544 	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
545 		return false;
546 
547 	smp_rmb();
548 
549 	/* Match the version and minorversion */
550 	if (clp->rpc_ops->version != 4 ||
551 	    clp->cl_minorversion != minorversion)
552 		return false;
553 
554 	/* Match only the IP address, not the port number */
555 	if (!nfs_sockaddr_match_ipaddr(addr, clap))
556 		return false;
557 
558 	return true;
559 }
560 
561 /*
562  * NFSv4.1 callback thread helper
563  * For CB_COMPOUND calls, find a client by IP address, protocol version,
564  * minorversion, and sessionID
565  *
566  * Returns NULL if no such client
567  */
568 struct nfs_client *
569 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
570 			   struct nfs4_sessionid *sid)
571 {
572 	struct nfs_client *clp;
573 	struct nfs_net *nn = net_generic(net, nfs_net_id);
574 
575 	spin_lock(&nn->nfs_client_lock);
576 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
577 		if (nfs4_cb_match_client(addr, clp, 1) == false)
578 			continue;
579 
580 		if (!nfs4_has_session(clp))
581 			continue;
582 
583 		/* Match sessionid*/
584 		if (memcmp(clp->cl_session->sess_id.data,
585 		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
586 			continue;
587 
588 		atomic_inc(&clp->cl_count);
589 		spin_unlock(&nn->nfs_client_lock);
590 		return clp;
591 	}
592 	spin_unlock(&nn->nfs_client_lock);
593 	return NULL;
594 }
595 
596 #else /* CONFIG_NFS_V4_1 */
597 
598 struct nfs_client *
599 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
600 			   struct nfs4_sessionid *sid)
601 {
602 	return NULL;
603 }
604 #endif /* CONFIG_NFS_V4_1 */
605 
606 /*
607  * Set up an NFS4 client
608  */
609 static int nfs4_set_client(struct nfs_server *server,
610 		const char *hostname,
611 		const struct sockaddr *addr,
612 		const size_t addrlen,
613 		const char *ip_addr,
614 		rpc_authflavor_t authflavour,
615 		int proto, const struct rpc_timeout *timeparms,
616 		u32 minorversion, struct net *net)
617 {
618 	struct nfs_client_initdata cl_init = {
619 		.hostname = hostname,
620 		.addr = addr,
621 		.addrlen = addrlen,
622 		.nfs_mod = &nfs_v4,
623 		.proto = proto,
624 		.minorversion = minorversion,
625 		.net = net,
626 	};
627 	struct nfs_client *clp;
628 	int error;
629 
630 	dprintk("--> nfs4_set_client()\n");
631 
632 	if (server->flags & NFS_MOUNT_NORESVPORT)
633 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
634 
635 	/* Allocate or find a client reference we can use */
636 	clp = nfs_get_client(&cl_init, timeparms, ip_addr, authflavour);
637 	if (IS_ERR(clp)) {
638 		error = PTR_ERR(clp);
639 		goto error;
640 	}
641 
642 	/*
643 	 * Query for the lease time on clientid setup or renewal
644 	 *
645 	 * Note that this will be set on nfs_clients that were created
646 	 * only for the DS role and did not set this bit, but now will
647 	 * serve a dual role.
648 	 */
649 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
650 
651 	server->nfs_client = clp;
652 	dprintk("<-- nfs4_set_client() = 0 [new %p]\n", clp);
653 	return 0;
654 error:
655 	dprintk("<-- nfs4_set_client() = xerror %d\n", error);
656 	return error;
657 }
658 
659 /*
660  * Set up a pNFS Data Server client.
661  *
662  * Return any existing nfs_client that matches server address,port,version
663  * and minorversion.
664  *
665  * For a new nfs_client, use a soft mount (default), a low retrans and a
666  * low timeout interval so that if a connection is lost, we retry through
667  * the MDS.
668  */
669 struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,
670 		const struct sockaddr *ds_addr, int ds_addrlen,
671 		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans)
672 {
673 	struct nfs_client_initdata cl_init = {
674 		.addr = ds_addr,
675 		.addrlen = ds_addrlen,
676 		.nfs_mod = &nfs_v4,
677 		.proto = ds_proto,
678 		.minorversion = mds_clp->cl_minorversion,
679 		.net = mds_clp->cl_net,
680 	};
681 	struct rpc_timeout ds_timeout;
682 	struct nfs_client *clp;
683 
684 	/*
685 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
686 	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
687 	 * (section 13.1 RFC 5661).
688 	 */
689 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
690 	clp = nfs_get_client(&cl_init, &ds_timeout, mds_clp->cl_ipaddr,
691 			     mds_clp->cl_rpcclient->cl_auth->au_flavor);
692 
693 	dprintk("<-- %s %p\n", __func__, clp);
694 	return clp;
695 }
696 EXPORT_SYMBOL_GPL(nfs4_set_ds_client);
697 
698 /*
699  * Session has been established, and the client marked ready.
700  * Set the mount rsize and wsize with negotiated fore channel
701  * attributes which will be bound checked in nfs_server_set_fsinfo.
702  */
703 static void nfs4_session_set_rwsize(struct nfs_server *server)
704 {
705 #ifdef CONFIG_NFS_V4_1
706 	struct nfs4_session *sess;
707 	u32 server_resp_sz;
708 	u32 server_rqst_sz;
709 
710 	if (!nfs4_has_session(server->nfs_client))
711 		return;
712 	sess = server->nfs_client->cl_session;
713 	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
714 	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
715 
716 	if (server->rsize > server_resp_sz)
717 		server->rsize = server_resp_sz;
718 	if (server->wsize > server_rqst_sz)
719 		server->wsize = server_rqst_sz;
720 #endif /* CONFIG_NFS_V4_1 */
721 }
722 
723 static int nfs4_server_common_setup(struct nfs_server *server,
724 		struct nfs_fh *mntfh)
725 {
726 	struct nfs_fattr *fattr;
727 	int error;
728 
729 	/* data servers support only a subset of NFSv4.1 */
730 	if (is_ds_only_client(server->nfs_client))
731 		return -EPROTONOSUPPORT;
732 
733 	fattr = nfs_alloc_fattr();
734 	if (fattr == NULL)
735 		return -ENOMEM;
736 
737 	/* We must ensure the session is initialised first */
738 	error = nfs4_init_session(server);
739 	if (error < 0)
740 		goto out;
741 
742 	/* Set the basic capabilities */
743 	server->caps |= server->nfs_client->cl_mvops->init_caps;
744 	if (server->flags & NFS_MOUNT_NORDIRPLUS)
745 			server->caps &= ~NFS_CAP_READDIRPLUS;
746 	/*
747 	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
748 	 * authentication.
749 	 */
750 	if (nfs4_disable_idmapping &&
751 			server->client->cl_auth->au_flavor == RPC_AUTH_UNIX)
752 		server->caps |= NFS_CAP_UIDGID_NOMAP;
753 
754 
755 	/* Probe the root fh to retrieve its FSID and filehandle */
756 	error = nfs4_get_rootfh(server, mntfh);
757 	if (error < 0)
758 		goto out;
759 
760 	dprintk("Server FSID: %llx:%llx\n",
761 			(unsigned long long) server->fsid.major,
762 			(unsigned long long) server->fsid.minor);
763 	dprintk("Mount FH: %d\n", mntfh->size);
764 
765 	nfs4_session_set_rwsize(server);
766 
767 	error = nfs_probe_fsinfo(server, mntfh, fattr);
768 	if (error < 0)
769 		goto out;
770 
771 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
772 		server->namelen = NFS4_MAXNAMLEN;
773 
774 	nfs_server_insert_lists(server);
775 	server->mount_time = jiffies;
776 	server->destroy = nfs4_destroy_server;
777 out:
778 	nfs_free_fattr(fattr);
779 	return error;
780 }
781 
782 /*
783  * Create a version 4 volume record
784  */
785 static int nfs4_init_server(struct nfs_server *server,
786 		const struct nfs_parsed_mount_data *data)
787 {
788 	struct rpc_timeout timeparms;
789 	int error;
790 
791 	dprintk("--> nfs4_init_server()\n");
792 
793 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
794 			data->timeo, data->retrans);
795 
796 	/* Initialise the client representation from the mount data */
797 	server->flags = data->flags;
798 	server->options = data->options;
799 
800 	/* Get a client record */
801 	error = nfs4_set_client(server,
802 			data->nfs_server.hostname,
803 			(const struct sockaddr *)&data->nfs_server.address,
804 			data->nfs_server.addrlen,
805 			data->client_address,
806 			data->auth_flavors[0],
807 			data->nfs_server.protocol,
808 			&timeparms,
809 			data->minorversion,
810 			data->net);
811 	if (error < 0)
812 		goto error;
813 
814 	if (data->rsize)
815 		server->rsize = nfs_block_size(data->rsize, NULL);
816 	if (data->wsize)
817 		server->wsize = nfs_block_size(data->wsize, NULL);
818 
819 	server->acregmin = data->acregmin * HZ;
820 	server->acregmax = data->acregmax * HZ;
821 	server->acdirmin = data->acdirmin * HZ;
822 	server->acdirmax = data->acdirmax * HZ;
823 
824 	server->port = data->nfs_server.port;
825 
826 	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
827 
828 error:
829 	/* Done */
830 	dprintk("<-- nfs4_init_server() = %d\n", error);
831 	return error;
832 }
833 
834 /*
835  * Create a version 4 volume record
836  * - keyed on server and FSID
837  */
838 /*struct nfs_server *nfs4_create_server(const struct nfs_parsed_mount_data *data,
839 				      struct nfs_fh *mntfh)*/
840 struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
841 				      struct nfs_subversion *nfs_mod)
842 {
843 	struct nfs_server *server;
844 	int error;
845 
846 	dprintk("--> nfs4_create_server()\n");
847 
848 	server = nfs_alloc_server();
849 	if (!server)
850 		return ERR_PTR(-ENOMEM);
851 
852 	/* set up the general RPC client */
853 	error = nfs4_init_server(server, mount_info->parsed);
854 	if (error < 0)
855 		goto error;
856 
857 	error = nfs4_server_common_setup(server, mount_info->mntfh);
858 	if (error < 0)
859 		goto error;
860 
861 	dprintk("<-- nfs4_create_server() = %p\n", server);
862 	return server;
863 
864 error:
865 	nfs_free_server(server);
866 	dprintk("<-- nfs4_create_server() = error %d\n", error);
867 	return ERR_PTR(error);
868 }
869 
870 /*
871  * Create an NFS4 referral server record
872  */
873 struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
874 					       struct nfs_fh *mntfh)
875 {
876 	struct nfs_client *parent_client;
877 	struct nfs_server *server, *parent_server;
878 	int error;
879 
880 	dprintk("--> nfs4_create_referral_server()\n");
881 
882 	server = nfs_alloc_server();
883 	if (!server)
884 		return ERR_PTR(-ENOMEM);
885 
886 	parent_server = NFS_SB(data->sb);
887 	parent_client = parent_server->nfs_client;
888 
889 	/* Initialise the client representation from the parent server */
890 	nfs_server_copy_userdata(server, parent_server);
891 
892 	/* Get a client representation.
893 	 * Note: NFSv4 always uses TCP, */
894 	error = nfs4_set_client(server, data->hostname,
895 				data->addr,
896 				data->addrlen,
897 				parent_client->cl_ipaddr,
898 				data->authflavor,
899 				rpc_protocol(parent_server->client),
900 				parent_server->client->cl_timeout,
901 				parent_client->cl_mvops->minor_version,
902 				parent_client->cl_net);
903 	if (error < 0)
904 		goto error;
905 
906 	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout, data->authflavor);
907 	if (error < 0)
908 		goto error;
909 
910 	error = nfs4_server_common_setup(server, mntfh);
911 	if (error < 0)
912 		goto error;
913 
914 	dprintk("<-- nfs_create_referral_server() = %p\n", server);
915 	return server;
916 
917 error:
918 	nfs_free_server(server);
919 	dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
920 	return ERR_PTR(error);
921 }
922