xref: /openbmc/linux/fs/nfs/nfs4client.c (revision 9659281c)
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 /**
406  * nfs4_init_client - Initialise an NFS4 client record
407  *
408  * @clp: nfs_client to initialise
409  * @cl_init: pointer to nfs_client_initdata
410  *
411  * Returns pointer to an NFS client, or an ERR_PTR value.
412  */
413 struct nfs_client *nfs4_init_client(struct nfs_client *clp,
414 				    const struct nfs_client_initdata *cl_init)
415 {
416 	struct nfs_client *old;
417 	int error;
418 
419 	if (clp->cl_cons_state == NFS_CS_READY)
420 		/* the client is initialised already */
421 		return clp;
422 
423 	error = nfs4_init_client_minor_version(clp);
424 	if (error < 0)
425 		goto error;
426 
427 	error = nfs4_discover_server_trunking(clp, &old);
428 	if (error < 0)
429 		goto error;
430 
431 	if (clp != old) {
432 		clp->cl_preserve_clid = true;
433 		/*
434 		 * Mark the client as having failed initialization so other
435 		 * processes walking the nfs_client_list in nfs_match_client()
436 		 * won't try to use it.
437 		 */
438 		nfs_mark_client_ready(clp, -EPERM);
439 	}
440 	clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
441 	nfs_put_client(clp);
442 	return old;
443 
444 error:
445 	nfs_mark_client_ready(clp, error);
446 	nfs_put_client(clp);
447 	return ERR_PTR(error);
448 }
449 
450 /*
451  * SETCLIENTID just did a callback update with the callback ident in
452  * "drop," but server trunking discovery claims "drop" and "keep" are
453  * actually the same server.  Swap the callback IDs so that "keep"
454  * will continue to use the callback ident the server now knows about,
455  * and so that "keep"'s original callback ident is destroyed when
456  * "drop" is freed.
457  */
458 static void nfs4_swap_callback_idents(struct nfs_client *keep,
459 				      struct nfs_client *drop)
460 {
461 	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
462 	unsigned int save = keep->cl_cb_ident;
463 
464 	if (keep->cl_cb_ident == drop->cl_cb_ident)
465 		return;
466 
467 	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
468 		__func__, keep->cl_cb_ident, drop->cl_cb_ident);
469 
470 	spin_lock(&nn->nfs_client_lock);
471 
472 	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
473 	keep->cl_cb_ident = drop->cl_cb_ident;
474 
475 	idr_replace(&nn->cb_ident_idr, drop, save);
476 	drop->cl_cb_ident = save;
477 
478 	spin_unlock(&nn->nfs_client_lock);
479 }
480 
481 static bool nfs4_match_client_owner_id(const struct nfs_client *clp1,
482 		const struct nfs_client *clp2)
483 {
484 	if (clp1->cl_owner_id == NULL || clp2->cl_owner_id == NULL)
485 		return true;
486 	return strcmp(clp1->cl_owner_id, clp2->cl_owner_id) == 0;
487 }
488 
489 static bool nfs4_same_verifier(nfs4_verifier *v1, nfs4_verifier *v2)
490 {
491 	return memcmp(v1->data, v2->data, sizeof(v1->data)) == 0;
492 }
493 
494 static int nfs4_match_client(struct nfs_client  *pos,  struct nfs_client *new,
495 			     struct nfs_client **prev, struct nfs_net *nn)
496 {
497 	int status;
498 
499 	if (pos->rpc_ops != new->rpc_ops)
500 		return 1;
501 
502 	if (pos->cl_minorversion != new->cl_minorversion)
503 		return 1;
504 
505 	/* If "pos" isn't marked ready, we can't trust the
506 	 * remaining fields in "pos", especially the client
507 	 * ID and serverowner fields.  Wait for CREATE_SESSION
508 	 * to finish. */
509 	if (pos->cl_cons_state > NFS_CS_READY) {
510 		refcount_inc(&pos->cl_count);
511 		spin_unlock(&nn->nfs_client_lock);
512 
513 		nfs_put_client(*prev);
514 		*prev = pos;
515 
516 		status = nfs_wait_client_init_complete(pos);
517 		spin_lock(&nn->nfs_client_lock);
518 
519 		if (status < 0)
520 			return status;
521 	}
522 
523 	if (pos->cl_cons_state != NFS_CS_READY)
524 		return 1;
525 
526 	if (pos->cl_clientid != new->cl_clientid)
527 		return 1;
528 
529 	/* NFSv4.1 always uses the uniform string, however someone
530 	 * might switch the uniquifier string on us.
531 	 */
532 	if (!nfs4_match_client_owner_id(pos, new))
533 		return 1;
534 
535 	return 0;
536 }
537 
538 /**
539  * nfs40_walk_client_list - Find server that recognizes a client ID
540  *
541  * @new: nfs_client with client ID to test
542  * @result: OUT: found nfs_client, or new
543  * @cred: credential to use for trunking test
544  *
545  * Returns zero, a negative errno, or a negative NFS4ERR status.
546  * If zero is returned, an nfs_client pointer is planted in "result."
547  *
548  * NB: nfs40_walk_client_list() relies on the new nfs_client being
549  *     the last nfs_client on the list.
550  */
551 int nfs40_walk_client_list(struct nfs_client *new,
552 			   struct nfs_client **result,
553 			   const struct cred *cred)
554 {
555 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
556 	struct nfs_client *pos, *prev = NULL;
557 	struct nfs4_setclientid_res clid = {
558 		.clientid	= new->cl_clientid,
559 		.confirm	= new->cl_confirm,
560 	};
561 	int status = -NFS4ERR_STALE_CLIENTID;
562 
563 	spin_lock(&nn->nfs_client_lock);
564 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
565 
566 		if (pos == new)
567 			goto found;
568 
569 		status = nfs4_match_client(pos, new, &prev, nn);
570 		if (status < 0)
571 			goto out_unlock;
572 		if (status != 0)
573 			continue;
574 		/*
575 		 * We just sent a new SETCLIENTID, which should have
576 		 * caused the server to return a new cl_confirm.  So if
577 		 * cl_confirm is the same, then this is a different
578 		 * server that just returned the same cl_confirm by
579 		 * coincidence:
580 		 */
581 		if ((new != pos) && nfs4_same_verifier(&pos->cl_confirm,
582 						       &new->cl_confirm))
583 			continue;
584 		/*
585 		 * But if the cl_confirm's are different, then the only
586 		 * way that a SETCLIENTID_CONFIRM to pos can succeed is
587 		 * if new and pos point to the same server:
588 		 */
589 found:
590 		refcount_inc(&pos->cl_count);
591 		spin_unlock(&nn->nfs_client_lock);
592 
593 		nfs_put_client(prev);
594 		prev = pos;
595 
596 		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
597 		switch (status) {
598 		case -NFS4ERR_STALE_CLIENTID:
599 			break;
600 		case 0:
601 			nfs4_swap_callback_idents(pos, new);
602 			pos->cl_confirm = new->cl_confirm;
603 			nfs_mark_client_ready(pos, NFS_CS_READY);
604 
605 			prev = NULL;
606 			*result = pos;
607 			goto out;
608 		case -ERESTARTSYS:
609 		case -ETIMEDOUT:
610 			/* The callback path may have been inadvertently
611 			 * changed. Schedule recovery!
612 			 */
613 			nfs4_schedule_path_down_recovery(pos);
614 			goto out;
615 		default:
616 			goto out;
617 		}
618 
619 		spin_lock(&nn->nfs_client_lock);
620 	}
621 out_unlock:
622 	spin_unlock(&nn->nfs_client_lock);
623 
624 	/* No match found. The server lost our clientid */
625 out:
626 	nfs_put_client(prev);
627 	return status;
628 }
629 
630 #ifdef CONFIG_NFS_V4_1
631 /*
632  * Returns true if the server major ids match
633  */
634 bool
635 nfs4_check_serverowner_major_id(struct nfs41_server_owner *o1,
636 				struct nfs41_server_owner *o2)
637 {
638 	if (o1->major_id_sz != o2->major_id_sz)
639 		return false;
640 	return memcmp(o1->major_id, o2->major_id, o1->major_id_sz) == 0;
641 }
642 
643 /*
644  * Returns true if the server scopes match
645  */
646 static bool
647 nfs4_check_server_scope(struct nfs41_server_scope *s1,
648 			struct nfs41_server_scope *s2)
649 {
650 	if (s1->server_scope_sz != s2->server_scope_sz)
651 		return false;
652 	return memcmp(s1->server_scope, s2->server_scope,
653 					s1->server_scope_sz) == 0;
654 }
655 
656 /**
657  * nfs4_detect_session_trunking - Checks for session trunking.
658  * @clp:    original mount nfs_client
659  * @res:    result structure from an exchange_id using the original mount
660  *          nfs_client with a new multi_addr transport
661  * @xprt:   pointer to the transport to add.
662  *
663  * Called after a successful EXCHANGE_ID on a multi-addr connection.
664  * Upon success, add the transport.
665  *
666  * Returns zero on success, otherwise -EINVAL
667  *
668  * Note: since the exchange_id for the new multi_addr transport uses the
669  * same nfs_client from the original mount, the cl_owner_id is reused,
670  * so eir_clientowner is the same.
671  */
672 int nfs4_detect_session_trunking(struct nfs_client *clp,
673 				 struct nfs41_exchange_id_res *res,
674 				 struct rpc_xprt *xprt)
675 {
676 	/* Check eir_clientid */
677 	if (clp->cl_clientid != res->clientid)
678 		goto out_err;
679 
680 	/* Check eir_server_owner so_major_id */
681 	if (!nfs4_check_serverowner_major_id(clp->cl_serverowner,
682 					     res->server_owner))
683 		goto out_err;
684 
685 	/* Check eir_server_owner so_minor_id */
686 	if (clp->cl_serverowner->minor_id != res->server_owner->minor_id)
687 		goto out_err;
688 
689 	/* Check eir_server_scope */
690 	if (!nfs4_check_server_scope(clp->cl_serverscope, res->server_scope))
691 		goto out_err;
692 
693 	pr_info("NFS:  %s: Session trunking succeeded for %s\n",
694 		clp->cl_hostname,
695 		xprt->address_strings[RPC_DISPLAY_ADDR]);
696 
697 	return 0;
698 out_err:
699 	pr_info("NFS:  %s: Session trunking failed for %s\n", clp->cl_hostname,
700 		xprt->address_strings[RPC_DISPLAY_ADDR]);
701 
702 	return -EINVAL;
703 }
704 
705 /**
706  * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
707  *
708  * @new: nfs_client with client ID to test
709  * @result: OUT: found nfs_client, or new
710  * @cred: credential to use for trunking test
711  *
712  * Returns zero, a negative errno, or a negative NFS4ERR status.
713  * If zero is returned, an nfs_client pointer is planted in "result."
714  *
715  * NB: nfs41_walk_client_list() relies on the new nfs_client being
716  *     the last nfs_client on the list.
717  */
718 int nfs41_walk_client_list(struct nfs_client *new,
719 			   struct nfs_client **result,
720 			   const struct cred *cred)
721 {
722 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
723 	struct nfs_client *pos, *prev = NULL;
724 	int status = -NFS4ERR_STALE_CLIENTID;
725 
726 	spin_lock(&nn->nfs_client_lock);
727 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
728 
729 		if (pos == new)
730 			goto found;
731 
732 		status = nfs4_match_client(pos, new, &prev, nn);
733 		if (status < 0)
734 			goto out;
735 		if (status != 0)
736 			continue;
737 
738 		/*
739 		 * Note that session trunking is just a special subcase of
740 		 * client id trunking. In either case, we want to fall back
741 		 * to using the existing nfs_client.
742 		 */
743 		if (!nfs4_check_serverowner_major_id(pos->cl_serverowner,
744 						     new->cl_serverowner))
745 			continue;
746 
747 found:
748 		refcount_inc(&pos->cl_count);
749 		*result = pos;
750 		status = 0;
751 		break;
752 	}
753 
754 out:
755 	spin_unlock(&nn->nfs_client_lock);
756 	nfs_put_client(prev);
757 	return status;
758 }
759 #endif	/* CONFIG_NFS_V4_1 */
760 
761 static void nfs4_destroy_server(struct nfs_server *server)
762 {
763 	LIST_HEAD(freeme);
764 
765 	nfs_server_return_all_delegations(server);
766 	unset_pnfs_layoutdriver(server);
767 	nfs4_purge_state_owners(server, &freeme);
768 	nfs4_free_state_owners(&freeme);
769 }
770 
771 /*
772  * NFSv4.0 callback thread helper
773  *
774  * Find a client by callback identifier
775  */
776 struct nfs_client *
777 nfs4_find_client_ident(struct net *net, int cb_ident)
778 {
779 	struct nfs_client *clp;
780 	struct nfs_net *nn = net_generic(net, nfs_net_id);
781 
782 	spin_lock(&nn->nfs_client_lock);
783 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
784 	if (clp)
785 		refcount_inc(&clp->cl_count);
786 	spin_unlock(&nn->nfs_client_lock);
787 	return clp;
788 }
789 
790 #if defined(CONFIG_NFS_V4_1)
791 /* Common match routine for v4.0 and v4.1 callback services */
792 static bool nfs4_cb_match_client(const struct sockaddr *addr,
793 		struct nfs_client *clp, u32 minorversion)
794 {
795 	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
796 
797 	/* Don't match clients that failed to initialise */
798 	if (!(clp->cl_cons_state == NFS_CS_READY ||
799 	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
800 		return false;
801 
802 	smp_rmb();
803 
804 	/* Match the version and minorversion */
805 	if (clp->rpc_ops->version != 4 ||
806 	    clp->cl_minorversion != minorversion)
807 		return false;
808 
809 	/* Match only the IP address, not the port number */
810 	return rpc_cmp_addr(addr, clap);
811 }
812 
813 /*
814  * NFSv4.1 callback thread helper
815  * For CB_COMPOUND calls, find a client by IP address, protocol version,
816  * minorversion, and sessionID
817  *
818  * Returns NULL if no such client
819  */
820 struct nfs_client *
821 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
822 			   struct nfs4_sessionid *sid, u32 minorversion)
823 {
824 	struct nfs_client *clp;
825 	struct nfs_net *nn = net_generic(net, nfs_net_id);
826 
827 	spin_lock(&nn->nfs_client_lock);
828 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
829 		if (!nfs4_cb_match_client(addr, clp, minorversion))
830 			continue;
831 
832 		if (!nfs4_has_session(clp))
833 			continue;
834 
835 		/* Match sessionid*/
836 		if (memcmp(clp->cl_session->sess_id.data,
837 		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
838 			continue;
839 
840 		refcount_inc(&clp->cl_count);
841 		spin_unlock(&nn->nfs_client_lock);
842 		return clp;
843 	}
844 	spin_unlock(&nn->nfs_client_lock);
845 	return NULL;
846 }
847 
848 #else /* CONFIG_NFS_V4_1 */
849 
850 struct nfs_client *
851 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
852 			   struct nfs4_sessionid *sid, u32 minorversion)
853 {
854 	return NULL;
855 }
856 #endif /* CONFIG_NFS_V4_1 */
857 
858 /*
859  * Set up an NFS4 client
860  */
861 static int nfs4_set_client(struct nfs_server *server,
862 		const char *hostname,
863 		const struct sockaddr *addr,
864 		const size_t addrlen,
865 		const char *ip_addr,
866 		int proto, const struct rpc_timeout *timeparms,
867 		u32 minorversion, unsigned int nconnect,
868 		struct net *net)
869 {
870 	struct nfs_client_initdata cl_init = {
871 		.hostname = hostname,
872 		.addr = addr,
873 		.addrlen = addrlen,
874 		.ip_addr = ip_addr,
875 		.nfs_mod = &nfs_v4,
876 		.proto = proto,
877 		.minorversion = minorversion,
878 		.net = net,
879 		.timeparms = timeparms,
880 		.cred = server->cred,
881 	};
882 	struct nfs_client *clp;
883 
884 	if (minorversion == 0)
885 		__set_bit(NFS_CS_REUSEPORT, &cl_init.init_flags);
886 	if (proto == XPRT_TRANSPORT_TCP)
887 		cl_init.nconnect = nconnect;
888 
889 	if (server->flags & NFS_MOUNT_NORESVPORT)
890 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
891 	if (server->options & NFS_OPTION_MIGRATION)
892 		__set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
893 	if (test_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status))
894 		__set_bit(NFS_CS_TSM_POSSIBLE, &cl_init.init_flags);
895 	server->port = rpc_get_port(addr);
896 
897 	/* Allocate or find a client reference we can use */
898 	clp = nfs_get_client(&cl_init);
899 	if (IS_ERR(clp))
900 		return PTR_ERR(clp);
901 
902 	if (server->nfs_client == clp) {
903 		nfs_put_client(clp);
904 		return -ELOOP;
905 	}
906 
907 	/*
908 	 * Query for the lease time on clientid setup or renewal
909 	 *
910 	 * Note that this will be set on nfs_clients that were created
911 	 * only for the DS role and did not set this bit, but now will
912 	 * serve a dual role.
913 	 */
914 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
915 
916 	server->nfs_client = clp;
917 	return 0;
918 }
919 
920 /*
921  * Set up a pNFS Data Server client.
922  *
923  * Return any existing nfs_client that matches server address,port,version
924  * and minorversion.
925  *
926  * For a new nfs_client, use a soft mount (default), a low retrans and a
927  * low timeout interval so that if a connection is lost, we retry through
928  * the MDS.
929  */
930 struct nfs_client *nfs4_set_ds_client(struct nfs_server *mds_srv,
931 		const struct sockaddr *ds_addr, int ds_addrlen,
932 		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans,
933 		u32 minor_version)
934 {
935 	struct rpc_timeout ds_timeout;
936 	struct nfs_client *mds_clp = mds_srv->nfs_client;
937 	struct nfs_client_initdata cl_init = {
938 		.addr = ds_addr,
939 		.addrlen = ds_addrlen,
940 		.nodename = mds_clp->cl_rpcclient->cl_nodename,
941 		.ip_addr = mds_clp->cl_ipaddr,
942 		.nfs_mod = &nfs_v4,
943 		.proto = ds_proto,
944 		.minorversion = minor_version,
945 		.net = mds_clp->cl_net,
946 		.timeparms = &ds_timeout,
947 		.cred = mds_srv->cred,
948 	};
949 	char buf[INET6_ADDRSTRLEN + 1];
950 
951 	if (rpc_ntop(ds_addr, buf, sizeof(buf)) <= 0)
952 		return ERR_PTR(-EINVAL);
953 	cl_init.hostname = buf;
954 
955 	if (mds_clp->cl_nconnect > 1 && ds_proto == XPRT_TRANSPORT_TCP)
956 		cl_init.nconnect = mds_clp->cl_nconnect;
957 
958 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
959 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
960 
961 	/*
962 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
963 	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
964 	 * (section 13.1 RFC 5661).
965 	 */
966 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
967 	return nfs_get_client(&cl_init);
968 }
969 EXPORT_SYMBOL_GPL(nfs4_set_ds_client);
970 
971 /*
972  * Session has been established, and the client marked ready.
973  * Limit the mount rsize, wsize and dtsize using negotiated fore
974  * channel attributes.
975  */
976 static void nfs4_session_limit_rwsize(struct nfs_server *server)
977 {
978 #ifdef CONFIG_NFS_V4_1
979 	struct nfs4_session *sess;
980 	u32 server_resp_sz;
981 	u32 server_rqst_sz;
982 
983 	if (!nfs4_has_session(server->nfs_client))
984 		return;
985 	sess = server->nfs_client->cl_session;
986 	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
987 	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
988 
989 	if (server->dtsize > server_resp_sz)
990 		server->dtsize = server_resp_sz;
991 	if (server->rsize > server_resp_sz)
992 		server->rsize = server_resp_sz;
993 	if (server->wsize > server_rqst_sz)
994 		server->wsize = server_rqst_sz;
995 #endif /* CONFIG_NFS_V4_1 */
996 }
997 
998 /*
999  * Limit xattr sizes using the channel attributes.
1000  */
1001 static void nfs4_session_limit_xasize(struct nfs_server *server)
1002 {
1003 #ifdef CONFIG_NFS_V4_2
1004 	struct nfs4_session *sess;
1005 	u32 server_gxa_sz;
1006 	u32 server_sxa_sz;
1007 	u32 server_lxa_sz;
1008 
1009 	if (!nfs4_has_session(server->nfs_client))
1010 		return;
1011 
1012 	sess = server->nfs_client->cl_session;
1013 
1014 	server_gxa_sz = sess->fc_attrs.max_resp_sz - nfs42_maxgetxattr_overhead;
1015 	server_sxa_sz = sess->fc_attrs.max_rqst_sz - nfs42_maxsetxattr_overhead;
1016 	server_lxa_sz = sess->fc_attrs.max_resp_sz -
1017 	    nfs42_maxlistxattrs_overhead;
1018 
1019 	if (server->gxasize > server_gxa_sz)
1020 		server->gxasize = server_gxa_sz;
1021 	if (server->sxasize > server_sxa_sz)
1022 		server->sxasize = server_sxa_sz;
1023 	if (server->lxasize > server_lxa_sz)
1024 		server->lxasize = server_lxa_sz;
1025 #endif
1026 }
1027 
1028 static int nfs4_server_common_setup(struct nfs_server *server,
1029 		struct nfs_fh *mntfh, bool auth_probe)
1030 {
1031 	struct nfs_fattr *fattr;
1032 	int error;
1033 
1034 	/* data servers support only a subset of NFSv4.1 */
1035 	if (is_ds_only_client(server->nfs_client))
1036 		return -EPROTONOSUPPORT;
1037 
1038 	fattr = nfs_alloc_fattr();
1039 	if (fattr == NULL)
1040 		return -ENOMEM;
1041 
1042 	/* We must ensure the session is initialised first */
1043 	error = nfs4_init_session(server->nfs_client);
1044 	if (error < 0)
1045 		goto out;
1046 
1047 	/* Set the basic capabilities */
1048 	server->caps |= server->nfs_client->cl_mvops->init_caps;
1049 	if (server->flags & NFS_MOUNT_NORDIRPLUS)
1050 			server->caps &= ~NFS_CAP_READDIRPLUS;
1051 	if (server->nfs_client->cl_proto == XPRT_TRANSPORT_RDMA)
1052 		server->caps &= ~NFS_CAP_READ_PLUS;
1053 	/*
1054 	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
1055 	 * authentication.
1056 	 */
1057 	if (nfs4_disable_idmapping &&
1058 			server->client->cl_auth->au_flavor == RPC_AUTH_UNIX)
1059 		server->caps |= NFS_CAP_UIDGID_NOMAP;
1060 
1061 
1062 	/* Probe the root fh to retrieve its FSID and filehandle */
1063 	error = nfs4_get_rootfh(server, mntfh, auth_probe);
1064 	if (error < 0)
1065 		goto out;
1066 
1067 	dprintk("Server FSID: %llx:%llx\n",
1068 			(unsigned long long) server->fsid.major,
1069 			(unsigned long long) server->fsid.minor);
1070 	nfs_display_fhandle(mntfh, "Pseudo-fs root FH");
1071 
1072 	error = nfs_probe_fsinfo(server, mntfh, fattr);
1073 	if (error < 0)
1074 		goto out;
1075 
1076 	nfs4_session_limit_rwsize(server);
1077 	nfs4_session_limit_xasize(server);
1078 
1079 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1080 		server->namelen = NFS4_MAXNAMLEN;
1081 
1082 	nfs_server_insert_lists(server);
1083 	server->mount_time = jiffies;
1084 	server->destroy = nfs4_destroy_server;
1085 out:
1086 	nfs_free_fattr(fattr);
1087 	return error;
1088 }
1089 
1090 /*
1091  * Create a version 4 volume record
1092  */
1093 static int nfs4_init_server(struct nfs_server *server, struct fs_context *fc)
1094 {
1095 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1096 	struct rpc_timeout timeparms;
1097 	int error;
1098 
1099 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
1100 				ctx->timeo, ctx->retrans);
1101 
1102 	/* Initialise the client representation from the mount data */
1103 	server->flags = ctx->flags;
1104 	server->options = ctx->options;
1105 	server->auth_info = ctx->auth_info;
1106 
1107 	/* Use the first specified auth flavor. If this flavor isn't
1108 	 * allowed by the server, use the SECINFO path to try the
1109 	 * other specified flavors */
1110 	if (ctx->auth_info.flavor_len >= 1)
1111 		ctx->selected_flavor = ctx->auth_info.flavors[0];
1112 	else
1113 		ctx->selected_flavor = RPC_AUTH_UNIX;
1114 
1115 	/* Get a client record */
1116 	error = nfs4_set_client(server,
1117 				ctx->nfs_server.hostname,
1118 				&ctx->nfs_server.address,
1119 				ctx->nfs_server.addrlen,
1120 				ctx->client_address,
1121 				ctx->nfs_server.protocol,
1122 				&timeparms,
1123 				ctx->minorversion,
1124 				ctx->nfs_server.nconnect,
1125 				fc->net_ns);
1126 	if (error < 0)
1127 		return error;
1128 
1129 	if (ctx->rsize)
1130 		server->rsize = nfs_block_size(ctx->rsize, NULL);
1131 	if (ctx->wsize)
1132 		server->wsize = nfs_block_size(ctx->wsize, NULL);
1133 
1134 	server->acregmin = ctx->acregmin * HZ;
1135 	server->acregmax = ctx->acregmax * HZ;
1136 	server->acdirmin = ctx->acdirmin * HZ;
1137 	server->acdirmax = ctx->acdirmax * HZ;
1138 	server->port     = ctx->nfs_server.port;
1139 
1140 	return nfs_init_server_rpcclient(server, &timeparms,
1141 					 ctx->selected_flavor);
1142 }
1143 
1144 /*
1145  * Create a version 4 volume record
1146  * - keyed on server and FSID
1147  */
1148 struct nfs_server *nfs4_create_server(struct fs_context *fc)
1149 {
1150 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1151 	struct nfs_server *server;
1152 	bool auth_probe;
1153 	int error;
1154 
1155 	server = nfs_alloc_server();
1156 	if (!server)
1157 		return ERR_PTR(-ENOMEM);
1158 
1159 	server->cred = get_cred(fc->cred);
1160 
1161 	auth_probe = ctx->auth_info.flavor_len < 1;
1162 
1163 	/* set up the general RPC client */
1164 	error = nfs4_init_server(server, fc);
1165 	if (error < 0)
1166 		goto error;
1167 
1168 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1169 	if (error < 0)
1170 		goto error;
1171 
1172 	return server;
1173 
1174 error:
1175 	nfs_free_server(server);
1176 	return ERR_PTR(error);
1177 }
1178 
1179 /*
1180  * Create an NFS4 referral server record
1181  */
1182 struct nfs_server *nfs4_create_referral_server(struct fs_context *fc)
1183 {
1184 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1185 	struct nfs_client *parent_client;
1186 	struct nfs_server *server, *parent_server;
1187 	bool auth_probe;
1188 	int error;
1189 
1190 	server = nfs_alloc_server();
1191 	if (!server)
1192 		return ERR_PTR(-ENOMEM);
1193 
1194 	parent_server = NFS_SB(ctx->clone_data.sb);
1195 	parent_client = parent_server->nfs_client;
1196 
1197 	server->cred = get_cred(parent_server->cred);
1198 
1199 	/* Initialise the client representation from the parent server */
1200 	nfs_server_copy_userdata(server, parent_server);
1201 
1202 	/* Get a client representation */
1203 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1204 	rpc_set_port(&ctx->nfs_server.address, NFS_RDMA_PORT);
1205 	error = nfs4_set_client(server,
1206 				ctx->nfs_server.hostname,
1207 				&ctx->nfs_server.address,
1208 				ctx->nfs_server.addrlen,
1209 				parent_client->cl_ipaddr,
1210 				XPRT_TRANSPORT_RDMA,
1211 				parent_server->client->cl_timeout,
1212 				parent_client->cl_mvops->minor_version,
1213 				parent_client->cl_nconnect,
1214 				parent_client->cl_net);
1215 	if (!error)
1216 		goto init_server;
1217 #endif	/* IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA) */
1218 
1219 	rpc_set_port(&ctx->nfs_server.address, NFS_PORT);
1220 	error = nfs4_set_client(server,
1221 				ctx->nfs_server.hostname,
1222 				&ctx->nfs_server.address,
1223 				ctx->nfs_server.addrlen,
1224 				parent_client->cl_ipaddr,
1225 				XPRT_TRANSPORT_TCP,
1226 				parent_server->client->cl_timeout,
1227 				parent_client->cl_mvops->minor_version,
1228 				parent_client->cl_nconnect,
1229 				parent_client->cl_net);
1230 	if (error < 0)
1231 		goto error;
1232 
1233 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1234 init_server:
1235 #endif
1236 	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout,
1237 					  ctx->selected_flavor);
1238 	if (error < 0)
1239 		goto error;
1240 
1241 	auth_probe = parent_server->auth_info.flavor_len < 1;
1242 
1243 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1244 	if (error < 0)
1245 		goto error;
1246 
1247 	return server;
1248 
1249 error:
1250 	nfs_free_server(server);
1251 	return ERR_PTR(error);
1252 }
1253 
1254 /*
1255  * Grab the destination's particulars, including lease expiry time.
1256  *
1257  * Returns zero if probe succeeded and retrieved FSID matches the FSID
1258  * we have cached.
1259  */
1260 static int nfs_probe_destination(struct nfs_server *server)
1261 {
1262 	struct inode *inode = d_inode(server->super->s_root);
1263 	struct nfs_fattr *fattr;
1264 	int error;
1265 
1266 	fattr = nfs_alloc_fattr();
1267 	if (fattr == NULL)
1268 		return -ENOMEM;
1269 
1270 	/* Sanity: the probe won't work if the destination server
1271 	 * does not recognize the migrated FH. */
1272 	error = nfs_probe_fsinfo(server, NFS_FH(inode), fattr);
1273 
1274 	nfs_free_fattr(fattr);
1275 	return error;
1276 }
1277 
1278 /**
1279  * nfs4_update_server - Move an nfs_server to a different nfs_client
1280  *
1281  * @server: represents FSID to be moved
1282  * @hostname: new end-point's hostname
1283  * @sap: new end-point's socket address
1284  * @salen: size of "sap"
1285  * @net: net namespace
1286  *
1287  * The nfs_server must be quiescent before this function is invoked.
1288  * Either its session is drained (NFSv4.1+), or its transport is
1289  * plugged and drained (NFSv4.0).
1290  *
1291  * Returns zero on success, or a negative errno value.
1292  */
1293 int nfs4_update_server(struct nfs_server *server, const char *hostname,
1294 		       struct sockaddr *sap, size_t salen, struct net *net)
1295 {
1296 	struct nfs_client *clp = server->nfs_client;
1297 	struct rpc_clnt *clnt = server->client;
1298 	struct xprt_create xargs = {
1299 		.ident		= clp->cl_proto,
1300 		.net		= net,
1301 		.dstaddr	= sap,
1302 		.addrlen	= salen,
1303 		.servername	= hostname,
1304 	};
1305 	char buf[INET6_ADDRSTRLEN + 1];
1306 	struct sockaddr_storage address;
1307 	struct sockaddr *localaddr = (struct sockaddr *)&address;
1308 	int error;
1309 
1310 	error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
1311 	if (error != 0)
1312 		return error;
1313 
1314 	error = rpc_localaddr(clnt, localaddr, sizeof(address));
1315 	if (error != 0)
1316 		return error;
1317 
1318 	if (rpc_ntop(localaddr, buf, sizeof(buf)) == 0)
1319 		return -EAFNOSUPPORT;
1320 
1321 	nfs_server_remove_lists(server);
1322 	set_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1323 	error = nfs4_set_client(server, hostname, sap, salen, buf,
1324 				clp->cl_proto, clnt->cl_timeout,
1325 				clp->cl_minorversion,
1326 				clp->cl_nconnect, net);
1327 	clear_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1328 	if (error != 0) {
1329 		nfs_server_insert_lists(server);
1330 		return error;
1331 	}
1332 	nfs_put_client(clp);
1333 
1334 	if (server->nfs_client->cl_hostname == NULL)
1335 		server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
1336 	nfs_server_insert_lists(server);
1337 
1338 	return nfs_probe_destination(server);
1339 }
1340