xref: /openbmc/linux/fs/nfs/nfs4client.c (revision f71a261a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  */
6 #include <linux/module.h>
7 #include <linux/nfs_fs.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 <linux/sunrpc/rpc_pipe_fs.h>
14 #include "internal.h"
15 #include "callback.h"
16 #include "delegation.h"
17 #include "nfs4session.h"
18 #include "nfs4idmap.h"
19 #include "pnfs.h"
20 #include "netns.h"
21 
22 #define NFSDBG_FACILITY		NFSDBG_CLIENT
23 
24 /*
25  * Get a unique NFSv4.0 callback identifier which will be used
26  * by the V4.0 callback service to lookup the nfs_client struct
27  */
28 static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
29 {
30 	int ret = 0;
31 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
32 
33 	if (clp->rpc_ops->version != 4 || minorversion != 0)
34 		return ret;
35 	idr_preload(GFP_KERNEL);
36 	spin_lock(&nn->nfs_client_lock);
37 	ret = idr_alloc(&nn->cb_ident_idr, clp, 1, 0, GFP_NOWAIT);
38 	if (ret >= 0)
39 		clp->cl_cb_ident = ret;
40 	spin_unlock(&nn->nfs_client_lock);
41 	idr_preload_end();
42 	return ret < 0 ? ret : 0;
43 }
44 
45 #ifdef CONFIG_NFS_V4_1
46 /*
47  * Per auth flavor data server rpc clients
48  */
49 struct nfs4_ds_server {
50 	struct list_head	list;   /* ds_clp->cl_ds_clients */
51 	struct rpc_clnt		*rpc_clnt;
52 };
53 
54 /**
55  * nfs4_find_ds_client - Common lookup case for DS I/O
56  * @ds_clp: pointer to the DS's nfs_client
57  * @flavor: rpc auth flavour to match
58  */
59 static struct nfs4_ds_server *
60 nfs4_find_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
61 {
62 	struct nfs4_ds_server *dss;
63 
64 	rcu_read_lock();
65 	list_for_each_entry_rcu(dss, &ds_clp->cl_ds_clients, list) {
66 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
67 			continue;
68 		goto out;
69 	}
70 	dss = NULL;
71 out:
72 	rcu_read_unlock();
73 	return dss;
74 }
75 
76 static struct nfs4_ds_server *
77 nfs4_add_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor,
78 			   struct nfs4_ds_server *new)
79 {
80 	struct nfs4_ds_server *dss;
81 
82 	spin_lock(&ds_clp->cl_lock);
83 	list_for_each_entry(dss, &ds_clp->cl_ds_clients, list) {
84 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
85 			continue;
86 		goto out;
87 	}
88 	if (new)
89 		list_add_rcu(&new->list, &ds_clp->cl_ds_clients);
90 	dss = new;
91 out:
92 	spin_unlock(&ds_clp->cl_lock); /* need some lock to protect list */
93 	return dss;
94 }
95 
96 static struct nfs4_ds_server *
97 nfs4_alloc_ds_server(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
98 {
99 	struct nfs4_ds_server *dss;
100 
101 	dss = kmalloc(sizeof(*dss), GFP_NOFS);
102 	if (dss == NULL)
103 		return ERR_PTR(-ENOMEM);
104 
105 	dss->rpc_clnt = rpc_clone_client_set_auth(ds_clp->cl_rpcclient, flavor);
106 	if (IS_ERR(dss->rpc_clnt)) {
107 		int err = PTR_ERR(dss->rpc_clnt);
108 		kfree (dss);
109 		return ERR_PTR(err);
110 	}
111 	INIT_LIST_HEAD(&dss->list);
112 
113 	return dss;
114 }
115 
116 static void
117 nfs4_free_ds_server(struct nfs4_ds_server *dss)
118 {
119 	rpc_release_client(dss->rpc_clnt);
120 	kfree(dss);
121 }
122 
123 /**
124  * nfs4_find_or_create_ds_client - Find or create a DS rpc client
125  * @ds_clp: pointer to the DS's nfs_client
126  * @inode: pointer to the inode
127  *
128  * Find or create a DS rpc client with th MDS server rpc client auth flavor
129  * in the nfs_client cl_ds_clients list.
130  */
131 struct rpc_clnt *
132 nfs4_find_or_create_ds_client(struct nfs_client *ds_clp, struct inode *inode)
133 {
134 	struct nfs4_ds_server *dss, *new;
135 	rpc_authflavor_t flavor = NFS_SERVER(inode)->client->cl_auth->au_flavor;
136 
137 	dss = nfs4_find_ds_client(ds_clp, flavor);
138 	if (dss != NULL)
139 		goto out;
140 	new = nfs4_alloc_ds_server(ds_clp, flavor);
141 	if (IS_ERR(new))
142 		return ERR_CAST(new);
143 	dss = nfs4_add_ds_client(ds_clp, flavor, new);
144 	if (dss != new)
145 		nfs4_free_ds_server(new);
146 out:
147 	return dss->rpc_clnt;
148 }
149 EXPORT_SYMBOL_GPL(nfs4_find_or_create_ds_client);
150 
151 static void
152 nfs4_shutdown_ds_clients(struct nfs_client *clp)
153 {
154 	struct nfs4_ds_server *dss;
155 
156 	while (!list_empty(&clp->cl_ds_clients)) {
157 		dss = list_entry(clp->cl_ds_clients.next,
158 					struct nfs4_ds_server, list);
159 		list_del(&dss->list);
160 		rpc_shutdown_client(dss->rpc_clnt);
161 		kfree (dss);
162 	}
163 }
164 
165 static void
166 nfs4_cleanup_callback(struct nfs_client *clp)
167 {
168 	struct nfs4_copy_state *cp_state;
169 
170 	while (!list_empty(&clp->pending_cb_stateids)) {
171 		cp_state = list_entry(clp->pending_cb_stateids.next,
172 					struct nfs4_copy_state, copies);
173 		list_del(&cp_state->copies);
174 		kfree(cp_state);
175 	}
176 }
177 
178 void nfs41_shutdown_client(struct nfs_client *clp)
179 {
180 	if (nfs4_has_session(clp)) {
181 		nfs4_cleanup_callback(clp);
182 		nfs4_shutdown_ds_clients(clp);
183 		nfs4_destroy_session(clp->cl_session);
184 		nfs4_destroy_clientid(clp);
185 	}
186 
187 }
188 #endif	/* CONFIG_NFS_V4_1 */
189 
190 void nfs40_shutdown_client(struct nfs_client *clp)
191 {
192 	if (clp->cl_slot_tbl) {
193 		nfs4_shutdown_slot_table(clp->cl_slot_tbl);
194 		kfree(clp->cl_slot_tbl);
195 	}
196 }
197 
198 struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
199 {
200 	char buf[INET6_ADDRSTRLEN + 1];
201 	const char *ip_addr = cl_init->ip_addr;
202 	struct nfs_client *clp = nfs_alloc_client(cl_init);
203 	int err;
204 
205 	if (IS_ERR(clp))
206 		return clp;
207 
208 	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
209 	if (err)
210 		goto error;
211 
212 	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
213 		err = -EINVAL;
214 		goto error;
215 	}
216 
217 	spin_lock_init(&clp->cl_lock);
218 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
219 	INIT_LIST_HEAD(&clp->cl_ds_clients);
220 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
221 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
222 	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
223 	clp->cl_mig_gen = 1;
224 #if IS_ENABLED(CONFIG_NFS_V4_1)
225 	init_waitqueue_head(&clp->cl_lock_waitq);
226 #endif
227 	INIT_LIST_HEAD(&clp->pending_cb_stateids);
228 
229 	if (cl_init->minorversion != 0)
230 		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
231 	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
232 	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
233 
234 	/*
235 	 * Set up the connection to the server before we add add to the
236 	 * global list.
237 	 */
238 	err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_GSS_KRB5I);
239 	if (err == -EINVAL)
240 		err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
241 	if (err < 0)
242 		goto error;
243 
244 	/* If no clientaddr= option was specified, find a usable cb address */
245 	if (ip_addr == NULL) {
246 		struct sockaddr_storage cb_addr;
247 		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
248 
249 		err = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
250 		if (err < 0)
251 			goto error;
252 		err = rpc_ntop(sap, buf, sizeof(buf));
253 		if (err < 0)
254 			goto error;
255 		ip_addr = (const char *)buf;
256 	}
257 	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
258 
259 	err = nfs_idmap_new(clp);
260 	if (err < 0) {
261 		dprintk("%s: failed to create idmapper. Error = %d\n",
262 			__func__, err);
263 		goto error;
264 	}
265 	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
266 	return clp;
267 
268 error:
269 	nfs_free_client(clp);
270 	return ERR_PTR(err);
271 }
272 
273 /*
274  * Destroy the NFS4 callback service
275  */
276 static void nfs4_destroy_callback(struct nfs_client *clp)
277 {
278 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
279 		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
280 }
281 
282 static void nfs4_shutdown_client(struct nfs_client *clp)
283 {
284 	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
285 		nfs4_kill_renewd(clp);
286 	clp->cl_mvops->shutdown_client(clp);
287 	nfs4_destroy_callback(clp);
288 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
289 		nfs_idmap_delete(clp);
290 
291 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
292 	kfree(clp->cl_serverowner);
293 	kfree(clp->cl_serverscope);
294 	kfree(clp->cl_implid);
295 	kfree(clp->cl_owner_id);
296 }
297 
298 void nfs4_free_client(struct nfs_client *clp)
299 {
300 	nfs4_shutdown_client(clp);
301 	nfs_free_client(clp);
302 }
303 
304 /*
305  * Initialize the NFS4 callback service
306  */
307 static int nfs4_init_callback(struct nfs_client *clp)
308 {
309 	struct rpc_xprt *xprt;
310 	int error;
311 
312 	xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);
313 
314 	if (nfs4_has_session(clp)) {
315 		error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
316 		if (error < 0)
317 			return error;
318 	}
319 
320 	error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
321 	if (error < 0) {
322 		dprintk("%s: failed to start callback. Error = %d\n",
323 			__func__, error);
324 		return error;
325 	}
326 	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
327 
328 	return 0;
329 }
330 
331 /**
332  * nfs40_init_client - nfs_client initialization tasks for NFSv4.0
333  * @clp: nfs_client to initialize
334  *
335  * Returns zero on success, or a negative errno if some error occurred.
336  */
337 int nfs40_init_client(struct nfs_client *clp)
338 {
339 	struct nfs4_slot_table *tbl;
340 	int ret;
341 
342 	tbl = kzalloc(sizeof(*tbl), GFP_NOFS);
343 	if (tbl == NULL)
344 		return -ENOMEM;
345 
346 	ret = nfs4_setup_slot_table(tbl, NFS4_MAX_SLOT_TABLE,
347 					"NFSv4.0 transport Slot table");
348 	if (ret) {
349 		kfree(tbl);
350 		return ret;
351 	}
352 
353 	clp->cl_slot_tbl = tbl;
354 	return 0;
355 }
356 
357 #if defined(CONFIG_NFS_V4_1)
358 
359 /**
360  * nfs41_init_client - nfs_client initialization tasks for NFSv4.1+
361  * @clp: nfs_client to initialize
362  *
363  * Returns zero on success, or a negative errno if some error occurred.
364  */
365 int nfs41_init_client(struct nfs_client *clp)
366 {
367 	struct nfs4_session *session = NULL;
368 
369 	/*
370 	 * Create the session and mark it expired.
371 	 * When a SEQUENCE operation encounters the expired session
372 	 * it will do session recovery to initialize it.
373 	 */
374 	session = nfs4_alloc_session(clp);
375 	if (!session)
376 		return -ENOMEM;
377 
378 	clp->cl_session = session;
379 
380 	/*
381 	 * The create session reply races with the server back
382 	 * channel probe. Mark the client NFS_CS_SESSION_INITING
383 	 * so that the client back channel can find the
384 	 * nfs_client struct
385 	 */
386 	nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
387 	return 0;
388 }
389 
390 #endif	/* CONFIG_NFS_V4_1 */
391 
392 /*
393  * Initialize the minor version specific parts of an NFS4 client record
394  */
395 static int nfs4_init_client_minor_version(struct nfs_client *clp)
396 {
397 	int ret;
398 
399 	ret = clp->cl_mvops->init_client(clp);
400 	if (ret)
401 		return ret;
402 	return nfs4_init_callback(clp);
403 }
404 
405 static void nfs4_add_trunk(struct nfs_client *clp, struct nfs_client *old)
406 {
407 	struct sockaddr_storage clp_addr, old_addr;
408 	struct sockaddr *clp_sap = (struct sockaddr *)&clp_addr;
409 	struct sockaddr *old_sap = (struct sockaddr *)&old_addr;
410 	size_t clp_salen;
411 	struct xprt_create xprt_args = {
412 		.ident = old->cl_proto,
413 		.net = old->cl_net,
414 		.servername = old->cl_hostname,
415 	};
416 
417 	if (clp->cl_proto != old->cl_proto)
418 		return;
419 	clp_salen = rpc_peeraddr(clp->cl_rpcclient, clp_sap, sizeof(clp_addr));
420 	rpc_peeraddr(old->cl_rpcclient, old_sap, sizeof(old_addr));
421 
422 	if (clp_addr.ss_family != old_addr.ss_family)
423 		return;
424 
425 	xprt_args.dstaddr = clp_sap;
426 	xprt_args.addrlen = clp_salen;
427 
428 	rpc_clnt_add_xprt(old->cl_rpcclient, &xprt_args,
429 			  rpc_clnt_test_and_add_xprt, NULL);
430 }
431 
432 /**
433  * nfs4_init_client - Initialise an NFS4 client record
434  *
435  * @clp: nfs_client to initialise
436  * @cl_init: pointer to nfs_client_initdata
437  *
438  * Returns pointer to an NFS client, or an ERR_PTR value.
439  */
440 struct nfs_client *nfs4_init_client(struct nfs_client *clp,
441 				    const struct nfs_client_initdata *cl_init)
442 {
443 	struct nfs_client *old;
444 	int error;
445 
446 	if (clp->cl_cons_state == NFS_CS_READY)
447 		/* the client is initialised already */
448 		return clp;
449 
450 	error = nfs4_init_client_minor_version(clp);
451 	if (error < 0)
452 		goto error;
453 
454 	error = nfs4_discover_server_trunking(clp, &old);
455 	if (error < 0)
456 		goto error;
457 
458 	if (clp != old) {
459 		clp->cl_preserve_clid = true;
460 		/*
461 		 * Mark the client as having failed initialization so other
462 		 * processes walking the nfs_client_list in nfs_match_client()
463 		 * won't try to use it.
464 		 */
465 		nfs_mark_client_ready(clp, -EPERM);
466 		if (old->cl_mvops->session_trunk)
467 			nfs4_add_trunk(clp, old);
468 	}
469 	clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
470 	nfs_put_client(clp);
471 	return old;
472 
473 error:
474 	nfs_mark_client_ready(clp, error);
475 	nfs_put_client(clp);
476 	return ERR_PTR(error);
477 }
478 
479 /*
480  * SETCLIENTID just did a callback update with the callback ident in
481  * "drop," but server trunking discovery claims "drop" and "keep" are
482  * actually the same server.  Swap the callback IDs so that "keep"
483  * will continue to use the callback ident the server now knows about,
484  * and so that "keep"'s original callback ident is destroyed when
485  * "drop" is freed.
486  */
487 static void nfs4_swap_callback_idents(struct nfs_client *keep,
488 				      struct nfs_client *drop)
489 {
490 	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
491 	unsigned int save = keep->cl_cb_ident;
492 
493 	if (keep->cl_cb_ident == drop->cl_cb_ident)
494 		return;
495 
496 	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
497 		__func__, keep->cl_cb_ident, drop->cl_cb_ident);
498 
499 	spin_lock(&nn->nfs_client_lock);
500 
501 	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
502 	keep->cl_cb_ident = drop->cl_cb_ident;
503 
504 	idr_replace(&nn->cb_ident_idr, drop, save);
505 	drop->cl_cb_ident = save;
506 
507 	spin_unlock(&nn->nfs_client_lock);
508 }
509 
510 static bool nfs4_match_client_owner_id(const struct nfs_client *clp1,
511 		const struct nfs_client *clp2)
512 {
513 	if (clp1->cl_owner_id == NULL || clp2->cl_owner_id == NULL)
514 		return true;
515 	return strcmp(clp1->cl_owner_id, clp2->cl_owner_id) == 0;
516 }
517 
518 static bool nfs4_same_verifier(nfs4_verifier *v1, nfs4_verifier *v2)
519 {
520 	return memcmp(v1->data, v2->data, sizeof(v1->data)) == 0;
521 }
522 
523 static int nfs4_match_client(struct nfs_client  *pos,  struct nfs_client *new,
524 			     struct nfs_client **prev, struct nfs_net *nn)
525 {
526 	int status;
527 
528 	if (pos->rpc_ops != new->rpc_ops)
529 		return 1;
530 
531 	if (pos->cl_minorversion != new->cl_minorversion)
532 		return 1;
533 
534 	/* If "pos" isn't marked ready, we can't trust the
535 	 * remaining fields in "pos", especially the client
536 	 * ID and serverowner fields.  Wait for CREATE_SESSION
537 	 * to finish. */
538 	if (pos->cl_cons_state > NFS_CS_READY) {
539 		refcount_inc(&pos->cl_count);
540 		spin_unlock(&nn->nfs_client_lock);
541 
542 		nfs_put_client(*prev);
543 		*prev = pos;
544 
545 		status = nfs_wait_client_init_complete(pos);
546 		spin_lock(&nn->nfs_client_lock);
547 
548 		if (status < 0)
549 			return status;
550 	}
551 
552 	if (pos->cl_cons_state != NFS_CS_READY)
553 		return 1;
554 
555 	if (pos->cl_clientid != new->cl_clientid)
556 		return 1;
557 
558 	/* NFSv4.1 always uses the uniform string, however someone
559 	 * might switch the uniquifier string on us.
560 	 */
561 	if (!nfs4_match_client_owner_id(pos, new))
562 		return 1;
563 
564 	return 0;
565 }
566 
567 /**
568  * nfs40_walk_client_list - Find server that recognizes a client ID
569  *
570  * @new: nfs_client with client ID to test
571  * @result: OUT: found nfs_client, or new
572  * @cred: credential to use for trunking test
573  *
574  * Returns zero, a negative errno, or a negative NFS4ERR status.
575  * If zero is returned, an nfs_client pointer is planted in "result."
576  *
577  * NB: nfs40_walk_client_list() relies on the new nfs_client being
578  *     the last nfs_client on the list.
579  */
580 int nfs40_walk_client_list(struct nfs_client *new,
581 			   struct nfs_client **result,
582 			   const struct cred *cred)
583 {
584 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
585 	struct nfs_client *pos, *prev = NULL;
586 	struct nfs4_setclientid_res clid = {
587 		.clientid	= new->cl_clientid,
588 		.confirm	= new->cl_confirm,
589 	};
590 	int status = -NFS4ERR_STALE_CLIENTID;
591 
592 	spin_lock(&nn->nfs_client_lock);
593 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
594 
595 		if (pos == new)
596 			goto found;
597 
598 		status = nfs4_match_client(pos, new, &prev, nn);
599 		if (status < 0)
600 			goto out_unlock;
601 		if (status != 0)
602 			continue;
603 		/*
604 		 * We just sent a new SETCLIENTID, which should have
605 		 * caused the server to return a new cl_confirm.  So if
606 		 * cl_confirm is the same, then this is a different
607 		 * server that just returned the same cl_confirm by
608 		 * coincidence:
609 		 */
610 		if ((new != pos) && nfs4_same_verifier(&pos->cl_confirm,
611 						       &new->cl_confirm))
612 			continue;
613 		/*
614 		 * But if the cl_confirm's are different, then the only
615 		 * way that a SETCLIENTID_CONFIRM to pos can succeed is
616 		 * if new and pos point to the same server:
617 		 */
618 found:
619 		refcount_inc(&pos->cl_count);
620 		spin_unlock(&nn->nfs_client_lock);
621 
622 		nfs_put_client(prev);
623 		prev = pos;
624 
625 		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
626 		switch (status) {
627 		case -NFS4ERR_STALE_CLIENTID:
628 			break;
629 		case 0:
630 			nfs4_swap_callback_idents(pos, new);
631 			pos->cl_confirm = new->cl_confirm;
632 			nfs_mark_client_ready(pos, NFS_CS_READY);
633 
634 			prev = NULL;
635 			*result = pos;
636 			goto out;
637 		case -ERESTARTSYS:
638 		case -ETIMEDOUT:
639 			/* The callback path may have been inadvertently
640 			 * changed. Schedule recovery!
641 			 */
642 			nfs4_schedule_path_down_recovery(pos);
643 			goto out;
644 		default:
645 			goto out;
646 		}
647 
648 		spin_lock(&nn->nfs_client_lock);
649 	}
650 out_unlock:
651 	spin_unlock(&nn->nfs_client_lock);
652 
653 	/* No match found. The server lost our clientid */
654 out:
655 	nfs_put_client(prev);
656 	return status;
657 }
658 
659 #ifdef CONFIG_NFS_V4_1
660 /*
661  * Returns true if the server major ids match
662  */
663 bool
664 nfs4_check_serverowner_major_id(struct nfs41_server_owner *o1,
665 				struct nfs41_server_owner *o2)
666 {
667 	if (o1->major_id_sz != o2->major_id_sz)
668 		return false;
669 	return memcmp(o1->major_id, o2->major_id, o1->major_id_sz) == 0;
670 }
671 
672 /*
673  * Returns true if the server scopes match
674  */
675 static bool
676 nfs4_check_server_scope(struct nfs41_server_scope *s1,
677 			struct nfs41_server_scope *s2)
678 {
679 	if (s1->server_scope_sz != s2->server_scope_sz)
680 		return false;
681 	return memcmp(s1->server_scope, s2->server_scope,
682 					s1->server_scope_sz) == 0;
683 }
684 
685 /**
686  * nfs4_detect_session_trunking - Checks for session trunking.
687  * @clp:    original mount nfs_client
688  * @res:    result structure from an exchange_id using the original mount
689  *          nfs_client with a new multi_addr transport
690  * @xprt:   pointer to the transport to add.
691  *
692  * Called after a successful EXCHANGE_ID on a multi-addr connection.
693  * Upon success, add the transport.
694  *
695  * Returns zero on success, otherwise -EINVAL
696  *
697  * Note: since the exchange_id for the new multi_addr transport uses the
698  * same nfs_client from the original mount, the cl_owner_id is reused,
699  * so eir_clientowner is the same.
700  */
701 int nfs4_detect_session_trunking(struct nfs_client *clp,
702 				 struct nfs41_exchange_id_res *res,
703 				 struct rpc_xprt *xprt)
704 {
705 	/* Check eir_clientid */
706 	if (clp->cl_clientid != res->clientid)
707 		goto out_err;
708 
709 	/* Check eir_server_owner so_major_id */
710 	if (!nfs4_check_serverowner_major_id(clp->cl_serverowner,
711 					     res->server_owner))
712 		goto out_err;
713 
714 	/* Check eir_server_owner so_minor_id */
715 	if (clp->cl_serverowner->minor_id != res->server_owner->minor_id)
716 		goto out_err;
717 
718 	/* Check eir_server_scope */
719 	if (!nfs4_check_server_scope(clp->cl_serverscope, res->server_scope))
720 		goto out_err;
721 
722 	pr_info("NFS:  %s: Session trunking succeeded for %s\n",
723 		clp->cl_hostname,
724 		xprt->address_strings[RPC_DISPLAY_ADDR]);
725 
726 	return 0;
727 out_err:
728 	pr_info("NFS:  %s: Session trunking failed for %s\n", clp->cl_hostname,
729 		xprt->address_strings[RPC_DISPLAY_ADDR]);
730 
731 	return -EINVAL;
732 }
733 
734 /**
735  * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
736  *
737  * @new: nfs_client with client ID to test
738  * @result: OUT: found nfs_client, or new
739  * @cred: credential to use for trunking test
740  *
741  * Returns zero, a negative errno, or a negative NFS4ERR status.
742  * If zero is returned, an nfs_client pointer is planted in "result."
743  *
744  * NB: nfs41_walk_client_list() relies on the new nfs_client being
745  *     the last nfs_client on the list.
746  */
747 int nfs41_walk_client_list(struct nfs_client *new,
748 			   struct nfs_client **result,
749 			   const struct cred *cred)
750 {
751 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
752 	struct nfs_client *pos, *prev = NULL;
753 	int status = -NFS4ERR_STALE_CLIENTID;
754 
755 	spin_lock(&nn->nfs_client_lock);
756 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
757 
758 		if (pos == new)
759 			goto found;
760 
761 		status = nfs4_match_client(pos, new, &prev, nn);
762 		if (status < 0)
763 			goto out;
764 		if (status != 0)
765 			continue;
766 
767 		/*
768 		 * Note that session trunking is just a special subcase of
769 		 * client id trunking. In either case, we want to fall back
770 		 * to using the existing nfs_client.
771 		 */
772 		if (!nfs4_check_serverowner_major_id(pos->cl_serverowner,
773 						     new->cl_serverowner))
774 			continue;
775 
776 found:
777 		refcount_inc(&pos->cl_count);
778 		*result = pos;
779 		status = 0;
780 		break;
781 	}
782 
783 out:
784 	spin_unlock(&nn->nfs_client_lock);
785 	nfs_put_client(prev);
786 	return status;
787 }
788 #endif	/* CONFIG_NFS_V4_1 */
789 
790 static void nfs4_destroy_server(struct nfs_server *server)
791 {
792 	LIST_HEAD(freeme);
793 
794 	nfs_server_return_all_delegations(server);
795 	unset_pnfs_layoutdriver(server);
796 	nfs4_purge_state_owners(server, &freeme);
797 	nfs4_free_state_owners(&freeme);
798 }
799 
800 /*
801  * NFSv4.0 callback thread helper
802  *
803  * Find a client by callback identifier
804  */
805 struct nfs_client *
806 nfs4_find_client_ident(struct net *net, int cb_ident)
807 {
808 	struct nfs_client *clp;
809 	struct nfs_net *nn = net_generic(net, nfs_net_id);
810 
811 	spin_lock(&nn->nfs_client_lock);
812 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
813 	if (clp)
814 		refcount_inc(&clp->cl_count);
815 	spin_unlock(&nn->nfs_client_lock);
816 	return clp;
817 }
818 
819 #if defined(CONFIG_NFS_V4_1)
820 /* Common match routine for v4.0 and v4.1 callback services */
821 static bool nfs4_cb_match_client(const struct sockaddr *addr,
822 		struct nfs_client *clp, u32 minorversion)
823 {
824 	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
825 
826 	/* Don't match clients that failed to initialise */
827 	if (!(clp->cl_cons_state == NFS_CS_READY ||
828 	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
829 		return false;
830 
831 	smp_rmb();
832 
833 	/* Match the version and minorversion */
834 	if (clp->rpc_ops->version != 4 ||
835 	    clp->cl_minorversion != minorversion)
836 		return false;
837 
838 	/* Match only the IP address, not the port number */
839 	return rpc_cmp_addr(addr, clap);
840 }
841 
842 /*
843  * NFSv4.1 callback thread helper
844  * For CB_COMPOUND calls, find a client by IP address, protocol version,
845  * minorversion, and sessionID
846  *
847  * Returns NULL if no such client
848  */
849 struct nfs_client *
850 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
851 			   struct nfs4_sessionid *sid, u32 minorversion)
852 {
853 	struct nfs_client *clp;
854 	struct nfs_net *nn = net_generic(net, nfs_net_id);
855 
856 	spin_lock(&nn->nfs_client_lock);
857 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
858 		if (!nfs4_cb_match_client(addr, clp, minorversion))
859 			continue;
860 
861 		if (!nfs4_has_session(clp))
862 			continue;
863 
864 		/* Match sessionid*/
865 		if (memcmp(clp->cl_session->sess_id.data,
866 		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
867 			continue;
868 
869 		refcount_inc(&clp->cl_count);
870 		spin_unlock(&nn->nfs_client_lock);
871 		return clp;
872 	}
873 	spin_unlock(&nn->nfs_client_lock);
874 	return NULL;
875 }
876 
877 #else /* CONFIG_NFS_V4_1 */
878 
879 struct nfs_client *
880 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
881 			   struct nfs4_sessionid *sid, u32 minorversion)
882 {
883 	return NULL;
884 }
885 #endif /* CONFIG_NFS_V4_1 */
886 
887 /*
888  * Set up an NFS4 client
889  */
890 static int nfs4_set_client(struct nfs_server *server,
891 		const char *hostname,
892 		const struct sockaddr *addr,
893 		const size_t addrlen,
894 		const char *ip_addr,
895 		int proto, const struct rpc_timeout *timeparms,
896 		u32 minorversion, unsigned int nconnect,
897 		unsigned int max_connect,
898 		struct net *net)
899 {
900 	struct nfs_client_initdata cl_init = {
901 		.hostname = hostname,
902 		.addr = addr,
903 		.addrlen = addrlen,
904 		.ip_addr = ip_addr,
905 		.nfs_mod = &nfs_v4,
906 		.proto = proto,
907 		.minorversion = minorversion,
908 		.net = net,
909 		.timeparms = timeparms,
910 		.cred = server->cred,
911 	};
912 	struct nfs_client *clp;
913 
914 	if (minorversion == 0)
915 		__set_bit(NFS_CS_REUSEPORT, &cl_init.init_flags);
916 	else
917 		cl_init.max_connect = max_connect;
918 	if (proto == XPRT_TRANSPORT_TCP)
919 		cl_init.nconnect = nconnect;
920 
921 	if (server->flags & NFS_MOUNT_NORESVPORT)
922 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
923 	if (server->options & NFS_OPTION_MIGRATION)
924 		__set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
925 	if (test_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status))
926 		__set_bit(NFS_CS_TSM_POSSIBLE, &cl_init.init_flags);
927 	server->port = rpc_get_port(addr);
928 
929 	/* Allocate or find a client reference we can use */
930 	clp = nfs_get_client(&cl_init);
931 	if (IS_ERR(clp))
932 		return PTR_ERR(clp);
933 
934 	if (server->nfs_client == clp) {
935 		nfs_put_client(clp);
936 		return -ELOOP;
937 	}
938 
939 	/*
940 	 * Query for the lease time on clientid setup or renewal
941 	 *
942 	 * Note that this will be set on nfs_clients that were created
943 	 * only for the DS role and did not set this bit, but now will
944 	 * serve a dual role.
945 	 */
946 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
947 
948 	server->nfs_client = clp;
949 	return 0;
950 }
951 
952 /*
953  * Set up a pNFS Data Server client.
954  *
955  * Return any existing nfs_client that matches server address,port,version
956  * and minorversion.
957  *
958  * For a new nfs_client, use a soft mount (default), a low retrans and a
959  * low timeout interval so that if a connection is lost, we retry through
960  * the MDS.
961  */
962 struct nfs_client *nfs4_set_ds_client(struct nfs_server *mds_srv,
963 		const struct sockaddr *ds_addr, int ds_addrlen,
964 		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans,
965 		u32 minor_version)
966 {
967 	struct rpc_timeout ds_timeout;
968 	struct nfs_client *mds_clp = mds_srv->nfs_client;
969 	struct nfs_client_initdata cl_init = {
970 		.addr = ds_addr,
971 		.addrlen = ds_addrlen,
972 		.nodename = mds_clp->cl_rpcclient->cl_nodename,
973 		.ip_addr = mds_clp->cl_ipaddr,
974 		.nfs_mod = &nfs_v4,
975 		.proto = ds_proto,
976 		.minorversion = minor_version,
977 		.net = mds_clp->cl_net,
978 		.timeparms = &ds_timeout,
979 		.cred = mds_srv->cred,
980 	};
981 	char buf[INET6_ADDRSTRLEN + 1];
982 
983 	if (rpc_ntop(ds_addr, buf, sizeof(buf)) <= 0)
984 		return ERR_PTR(-EINVAL);
985 	cl_init.hostname = buf;
986 
987 	if (mds_clp->cl_nconnect > 1 && ds_proto == XPRT_TRANSPORT_TCP) {
988 		cl_init.nconnect = mds_clp->cl_nconnect;
989 		cl_init.max_connect = NFS_MAX_TRANSPORTS;
990 	}
991 
992 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
993 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
994 
995 	/*
996 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
997 	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
998 	 * (section 13.1 RFC 5661).
999 	 */
1000 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
1001 	return nfs_get_client(&cl_init);
1002 }
1003 EXPORT_SYMBOL_GPL(nfs4_set_ds_client);
1004 
1005 /*
1006  * Session has been established, and the client marked ready.
1007  * Limit the mount rsize, wsize and dtsize using negotiated fore
1008  * channel attributes.
1009  */
1010 static void nfs4_session_limit_rwsize(struct nfs_server *server)
1011 {
1012 #ifdef CONFIG_NFS_V4_1
1013 	struct nfs4_session *sess;
1014 	u32 server_resp_sz;
1015 	u32 server_rqst_sz;
1016 
1017 	if (!nfs4_has_session(server->nfs_client))
1018 		return;
1019 	sess = server->nfs_client->cl_session;
1020 	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
1021 	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
1022 
1023 	if (server->dtsize > server_resp_sz)
1024 		server->dtsize = server_resp_sz;
1025 	if (server->rsize > server_resp_sz)
1026 		server->rsize = server_resp_sz;
1027 	if (server->wsize > server_rqst_sz)
1028 		server->wsize = server_rqst_sz;
1029 #endif /* CONFIG_NFS_V4_1 */
1030 }
1031 
1032 /*
1033  * Limit xattr sizes using the channel attributes.
1034  */
1035 static void nfs4_session_limit_xasize(struct nfs_server *server)
1036 {
1037 #ifdef CONFIG_NFS_V4_2
1038 	struct nfs4_session *sess;
1039 	u32 server_gxa_sz;
1040 	u32 server_sxa_sz;
1041 	u32 server_lxa_sz;
1042 
1043 	if (!nfs4_has_session(server->nfs_client))
1044 		return;
1045 
1046 	sess = server->nfs_client->cl_session;
1047 
1048 	server_gxa_sz = sess->fc_attrs.max_resp_sz - nfs42_maxgetxattr_overhead;
1049 	server_sxa_sz = sess->fc_attrs.max_rqst_sz - nfs42_maxsetxattr_overhead;
1050 	server_lxa_sz = sess->fc_attrs.max_resp_sz -
1051 	    nfs42_maxlistxattrs_overhead;
1052 
1053 	if (server->gxasize > server_gxa_sz)
1054 		server->gxasize = server_gxa_sz;
1055 	if (server->sxasize > server_sxa_sz)
1056 		server->sxasize = server_sxa_sz;
1057 	if (server->lxasize > server_lxa_sz)
1058 		server->lxasize = server_lxa_sz;
1059 #endif
1060 }
1061 
1062 void nfs4_server_set_init_caps(struct nfs_server *server)
1063 {
1064 	/* Set the basic capabilities */
1065 	server->caps |= server->nfs_client->cl_mvops->init_caps;
1066 	if (server->flags & NFS_MOUNT_NORDIRPLUS)
1067 			server->caps &= ~NFS_CAP_READDIRPLUS;
1068 	if (server->nfs_client->cl_proto == XPRT_TRANSPORT_RDMA)
1069 		server->caps &= ~NFS_CAP_READ_PLUS;
1070 
1071 	/*
1072 	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
1073 	 * authentication.
1074 	 */
1075 	if (nfs4_disable_idmapping &&
1076 			server->client->cl_auth->au_flavor == RPC_AUTH_UNIX)
1077 		server->caps |= NFS_CAP_UIDGID_NOMAP;
1078 }
1079 
1080 static int nfs4_server_common_setup(struct nfs_server *server,
1081 		struct nfs_fh *mntfh, bool auth_probe)
1082 {
1083 	int error;
1084 
1085 	/* data servers support only a subset of NFSv4.1 */
1086 	if (is_ds_only_client(server->nfs_client))
1087 		return -EPROTONOSUPPORT;
1088 
1089 	/* We must ensure the session is initialised first */
1090 	error = nfs4_init_session(server->nfs_client);
1091 	if (error < 0)
1092 		goto out;
1093 
1094 	nfs4_server_set_init_caps(server);
1095 
1096 	/* Probe the root fh to retrieve its FSID and filehandle */
1097 	error = nfs4_get_rootfh(server, mntfh, auth_probe);
1098 	if (error < 0)
1099 		goto out;
1100 
1101 	dprintk("Server FSID: %llx:%llx\n",
1102 			(unsigned long long) server->fsid.major,
1103 			(unsigned long long) server->fsid.minor);
1104 	nfs_display_fhandle(mntfh, "Pseudo-fs root FH");
1105 
1106 	error = nfs_probe_server(server, mntfh);
1107 	if (error < 0)
1108 		goto out;
1109 
1110 	nfs4_session_limit_rwsize(server);
1111 	nfs4_session_limit_xasize(server);
1112 
1113 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1114 		server->namelen = NFS4_MAXNAMLEN;
1115 
1116 	nfs_server_insert_lists(server);
1117 	server->mount_time = jiffies;
1118 	server->destroy = nfs4_destroy_server;
1119 out:
1120 	return error;
1121 }
1122 
1123 /*
1124  * Create a version 4 volume record
1125  */
1126 static int nfs4_init_server(struct nfs_server *server, struct fs_context *fc)
1127 {
1128 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1129 	struct rpc_timeout timeparms;
1130 	int error;
1131 
1132 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
1133 				ctx->timeo, ctx->retrans);
1134 
1135 	/* Initialise the client representation from the mount data */
1136 	server->flags = ctx->flags;
1137 	server->options = ctx->options;
1138 	server->auth_info = ctx->auth_info;
1139 
1140 	/* Use the first specified auth flavor. If this flavor isn't
1141 	 * allowed by the server, use the SECINFO path to try the
1142 	 * other specified flavors */
1143 	if (ctx->auth_info.flavor_len >= 1)
1144 		ctx->selected_flavor = ctx->auth_info.flavors[0];
1145 	else
1146 		ctx->selected_flavor = RPC_AUTH_UNIX;
1147 
1148 	/* Get a client record */
1149 	error = nfs4_set_client(server,
1150 				ctx->nfs_server.hostname,
1151 				&ctx->nfs_server.address,
1152 				ctx->nfs_server.addrlen,
1153 				ctx->client_address,
1154 				ctx->nfs_server.protocol,
1155 				&timeparms,
1156 				ctx->minorversion,
1157 				ctx->nfs_server.nconnect,
1158 				ctx->nfs_server.max_connect,
1159 				fc->net_ns);
1160 	if (error < 0)
1161 		return error;
1162 
1163 	if (ctx->rsize)
1164 		server->rsize = nfs_block_size(ctx->rsize, NULL);
1165 	if (ctx->wsize)
1166 		server->wsize = nfs_block_size(ctx->wsize, NULL);
1167 
1168 	server->acregmin = ctx->acregmin * HZ;
1169 	server->acregmax = ctx->acregmax * HZ;
1170 	server->acdirmin = ctx->acdirmin * HZ;
1171 	server->acdirmax = ctx->acdirmax * HZ;
1172 	server->port     = ctx->nfs_server.port;
1173 
1174 	return nfs_init_server_rpcclient(server, &timeparms,
1175 					 ctx->selected_flavor);
1176 }
1177 
1178 /*
1179  * Create a version 4 volume record
1180  * - keyed on server and FSID
1181  */
1182 struct nfs_server *nfs4_create_server(struct fs_context *fc)
1183 {
1184 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1185 	struct nfs_server *server;
1186 	bool auth_probe;
1187 	int error;
1188 
1189 	server = nfs_alloc_server();
1190 	if (!server)
1191 		return ERR_PTR(-ENOMEM);
1192 
1193 	server->cred = get_cred(fc->cred);
1194 
1195 	auth_probe = ctx->auth_info.flavor_len < 1;
1196 
1197 	/* set up the general RPC client */
1198 	error = nfs4_init_server(server, fc);
1199 	if (error < 0)
1200 		goto error;
1201 
1202 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1203 	if (error < 0)
1204 		goto error;
1205 
1206 	return server;
1207 
1208 error:
1209 	nfs_free_server(server);
1210 	return ERR_PTR(error);
1211 }
1212 
1213 /*
1214  * Create an NFS4 referral server record
1215  */
1216 struct nfs_server *nfs4_create_referral_server(struct fs_context *fc)
1217 {
1218 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1219 	struct nfs_client *parent_client;
1220 	struct nfs_server *server, *parent_server;
1221 	bool auth_probe;
1222 	int error;
1223 
1224 	server = nfs_alloc_server();
1225 	if (!server)
1226 		return ERR_PTR(-ENOMEM);
1227 
1228 	parent_server = NFS_SB(ctx->clone_data.sb);
1229 	parent_client = parent_server->nfs_client;
1230 
1231 	server->cred = get_cred(parent_server->cred);
1232 
1233 	/* Initialise the client representation from the parent server */
1234 	nfs_server_copy_userdata(server, parent_server);
1235 
1236 	/* Get a client representation */
1237 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1238 	rpc_set_port(&ctx->nfs_server.address, NFS_RDMA_PORT);
1239 	error = nfs4_set_client(server,
1240 				ctx->nfs_server.hostname,
1241 				&ctx->nfs_server.address,
1242 				ctx->nfs_server.addrlen,
1243 				parent_client->cl_ipaddr,
1244 				XPRT_TRANSPORT_RDMA,
1245 				parent_server->client->cl_timeout,
1246 				parent_client->cl_mvops->minor_version,
1247 				parent_client->cl_nconnect,
1248 				parent_client->cl_max_connect,
1249 				parent_client->cl_net);
1250 	if (!error)
1251 		goto init_server;
1252 #endif	/* IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA) */
1253 
1254 	rpc_set_port(&ctx->nfs_server.address, NFS_PORT);
1255 	error = nfs4_set_client(server,
1256 				ctx->nfs_server.hostname,
1257 				&ctx->nfs_server.address,
1258 				ctx->nfs_server.addrlen,
1259 				parent_client->cl_ipaddr,
1260 				XPRT_TRANSPORT_TCP,
1261 				parent_server->client->cl_timeout,
1262 				parent_client->cl_mvops->minor_version,
1263 				parent_client->cl_nconnect,
1264 				parent_client->cl_max_connect,
1265 				parent_client->cl_net);
1266 	if (error < 0)
1267 		goto error;
1268 
1269 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1270 init_server:
1271 #endif
1272 	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout,
1273 					  ctx->selected_flavor);
1274 	if (error < 0)
1275 		goto error;
1276 
1277 	auth_probe = parent_server->auth_info.flavor_len < 1;
1278 
1279 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1280 	if (error < 0)
1281 		goto error;
1282 
1283 	return server;
1284 
1285 error:
1286 	nfs_free_server(server);
1287 	return ERR_PTR(error);
1288 }
1289 
1290 /**
1291  * nfs4_update_server - Move an nfs_server to a different nfs_client
1292  *
1293  * @server: represents FSID to be moved
1294  * @hostname: new end-point's hostname
1295  * @sap: new end-point's socket address
1296  * @salen: size of "sap"
1297  * @net: net namespace
1298  *
1299  * The nfs_server must be quiescent before this function is invoked.
1300  * Either its session is drained (NFSv4.1+), or its transport is
1301  * plugged and drained (NFSv4.0).
1302  *
1303  * Returns zero on success, or a negative errno value.
1304  */
1305 int nfs4_update_server(struct nfs_server *server, const char *hostname,
1306 		       struct sockaddr *sap, size_t salen, struct net *net)
1307 {
1308 	struct nfs_client *clp = server->nfs_client;
1309 	struct rpc_clnt *clnt = server->client;
1310 	struct xprt_create xargs = {
1311 		.ident		= clp->cl_proto,
1312 		.net		= net,
1313 		.dstaddr	= sap,
1314 		.addrlen	= salen,
1315 		.servername	= hostname,
1316 	};
1317 	char buf[INET6_ADDRSTRLEN + 1];
1318 	struct sockaddr_storage address;
1319 	struct sockaddr *localaddr = (struct sockaddr *)&address;
1320 	int error;
1321 
1322 	error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
1323 	if (error != 0)
1324 		return error;
1325 
1326 	error = rpc_localaddr(clnt, localaddr, sizeof(address));
1327 	if (error != 0)
1328 		return error;
1329 
1330 	if (rpc_ntop(localaddr, buf, sizeof(buf)) == 0)
1331 		return -EAFNOSUPPORT;
1332 
1333 	nfs_server_remove_lists(server);
1334 	set_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1335 	error = nfs4_set_client(server, hostname, sap, salen, buf,
1336 				clp->cl_proto, clnt->cl_timeout,
1337 				clp->cl_minorversion,
1338 				clp->cl_nconnect, clp->cl_max_connect, net);
1339 	clear_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1340 	if (error != 0) {
1341 		nfs_server_insert_lists(server);
1342 		return error;
1343 	}
1344 	nfs_put_client(clp);
1345 
1346 	if (server->nfs_client->cl_hostname == NULL) {
1347 		server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
1348 		if (server->nfs_client->cl_hostname == NULL)
1349 			return -ENOMEM;
1350 	}
1351 	nfs_server_insert_lists(server);
1352 
1353 	return nfs_probe_server(server, NFS_FH(d_inode(server->super->s_root)));
1354 }
1355