xref: /linux/fs/nfs/nfs4client.c (revision 9abd613a85af72fa560e49d9a0acc5b872840c72)
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 #include "sysfs.h"
22 
23 #define NFSDBG_FACILITY		NFSDBG_CLIENT
24 
25 /*
26  * Get a unique NFSv4.0 callback identifier which will be used
27  * by the V4.0 callback service to lookup the nfs_client struct
28  */
29 static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
30 {
31 	int ret = 0;
32 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
33 
34 	if (clp->rpc_ops->version != 4 || minorversion != 0)
35 		return ret;
36 	idr_preload(GFP_KERNEL);
37 	spin_lock(&nn->nfs_client_lock);
38 	ret = idr_alloc(&nn->cb_ident_idr, clp, 1, 0, GFP_NOWAIT);
39 	if (ret >= 0)
40 		clp->cl_cb_ident = ret;
41 	spin_unlock(&nn->nfs_client_lock);
42 	idr_preload_end();
43 	return ret < 0 ? ret : 0;
44 }
45 
46 #ifdef CONFIG_NFS_V4_1
47 /*
48  * Per auth flavor data server rpc clients
49  */
50 struct nfs4_ds_server {
51 	struct list_head	list;   /* ds_clp->cl_ds_clients */
52 	struct rpc_clnt		*rpc_clnt;
53 };
54 
55 /**
56  * nfs4_find_ds_client - Common lookup case for DS I/O
57  * @ds_clp: pointer to the DS's nfs_client
58  * @flavor: rpc auth flavour to match
59  */
60 static struct nfs4_ds_server *
61 nfs4_find_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
62 {
63 	struct nfs4_ds_server *dss;
64 
65 	rcu_read_lock();
66 	list_for_each_entry_rcu(dss, &ds_clp->cl_ds_clients, list) {
67 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
68 			continue;
69 		goto out;
70 	}
71 	dss = NULL;
72 out:
73 	rcu_read_unlock();
74 	return dss;
75 }
76 
77 static struct nfs4_ds_server *
78 nfs4_add_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor,
79 			   struct nfs4_ds_server *new)
80 {
81 	struct nfs4_ds_server *dss;
82 
83 	spin_lock(&ds_clp->cl_lock);
84 	list_for_each_entry(dss, &ds_clp->cl_ds_clients, list) {
85 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
86 			continue;
87 		goto out;
88 	}
89 	if (new)
90 		list_add_rcu(&new->list, &ds_clp->cl_ds_clients);
91 	dss = new;
92 out:
93 	spin_unlock(&ds_clp->cl_lock); /* need some lock to protect list */
94 	return dss;
95 }
96 
97 static struct nfs4_ds_server *
98 nfs4_alloc_ds_server(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
99 {
100 	struct nfs4_ds_server *dss;
101 
102 	dss = kmalloc(sizeof(*dss), GFP_NOFS);
103 	if (dss == NULL)
104 		return ERR_PTR(-ENOMEM);
105 
106 	dss->rpc_clnt = rpc_clone_client_set_auth(ds_clp->cl_rpcclient, flavor);
107 	if (IS_ERR(dss->rpc_clnt)) {
108 		int err = PTR_ERR(dss->rpc_clnt);
109 		kfree (dss);
110 		return ERR_PTR(err);
111 	}
112 	INIT_LIST_HEAD(&dss->list);
113 
114 	return dss;
115 }
116 
117 static void
118 nfs4_free_ds_server(struct nfs4_ds_server *dss)
119 {
120 	rpc_release_client(dss->rpc_clnt);
121 	kfree(dss);
122 }
123 
124 /**
125  * nfs4_find_or_create_ds_client - Find or create a DS rpc client
126  * @ds_clp: pointer to the DS's nfs_client
127  * @inode: pointer to the inode
128  *
129  * Find or create a DS rpc client with th MDS server rpc client auth flavor
130  * in the nfs_client cl_ds_clients list.
131  */
132 struct rpc_clnt *
133 nfs4_find_or_create_ds_client(struct nfs_client *ds_clp, struct inode *inode)
134 {
135 	struct nfs4_ds_server *dss, *new;
136 	rpc_authflavor_t flavor = NFS_SERVER(inode)->client->cl_auth->au_flavor;
137 
138 	dss = nfs4_find_ds_client(ds_clp, flavor);
139 	if (dss != NULL)
140 		goto out;
141 	new = nfs4_alloc_ds_server(ds_clp, flavor);
142 	if (IS_ERR(new))
143 		return ERR_CAST(new);
144 	dss = nfs4_add_ds_client(ds_clp, flavor, new);
145 	if (dss != new)
146 		nfs4_free_ds_server(new);
147 out:
148 	return dss->rpc_clnt;
149 }
150 EXPORT_SYMBOL_GPL(nfs4_find_or_create_ds_client);
151 
152 static void
153 nfs4_shutdown_ds_clients(struct nfs_client *clp)
154 {
155 	struct nfs4_ds_server *dss;
156 
157 	while (!list_empty(&clp->cl_ds_clients)) {
158 		dss = list_entry(clp->cl_ds_clients.next,
159 					struct nfs4_ds_server, list);
160 		list_del(&dss->list);
161 		rpc_shutdown_client(dss->rpc_clnt);
162 		kfree (dss);
163 	}
164 }
165 
166 static void
167 nfs4_cleanup_callback(struct nfs_client *clp)
168 {
169 	struct nfs4_copy_state *cp_state;
170 
171 	while (!list_empty(&clp->pending_cb_stateids)) {
172 		cp_state = list_entry(clp->pending_cb_stateids.next,
173 					struct nfs4_copy_state, copies);
174 		list_del(&cp_state->copies);
175 		kfree(cp_state);
176 	}
177 }
178 
179 void nfs41_shutdown_client(struct nfs_client *clp)
180 {
181 	if (nfs4_has_session(clp)) {
182 		nfs4_cleanup_callback(clp);
183 		nfs4_shutdown_ds_clients(clp);
184 		nfs4_destroy_session(clp->cl_session);
185 		nfs4_destroy_clientid(clp);
186 	}
187 
188 }
189 #endif	/* CONFIG_NFS_V4_1 */
190 
191 void nfs40_shutdown_client(struct nfs_client *clp)
192 {
193 	if (clp->cl_slot_tbl) {
194 		nfs4_shutdown_slot_table(clp->cl_slot_tbl);
195 		kfree(clp->cl_slot_tbl);
196 	}
197 }
198 
199 struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
200 {
201 	char buf[INET6_ADDRSTRLEN + 1];
202 	const char *ip_addr = cl_init->ip_addr;
203 	struct nfs_client *clp = nfs_alloc_client(cl_init);
204 	int err;
205 
206 	if (IS_ERR(clp))
207 		return clp;
208 
209 	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
210 	if (err)
211 		goto error;
212 
213 	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
214 		err = -EINVAL;
215 		goto error;
216 	}
217 
218 	spin_lock_init(&clp->cl_lock);
219 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
220 	INIT_LIST_HEAD(&clp->cl_ds_clients);
221 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
222 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
223 	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
224 	clp->cl_mig_gen = 1;
225 #if IS_ENABLED(CONFIG_NFS_V4_1)
226 	init_waitqueue_head(&clp->cl_lock_waitq);
227 #endif
228 	INIT_LIST_HEAD(&clp->pending_cb_stateids);
229 
230 	if (cl_init->minorversion != 0)
231 		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
232 	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
233 	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
234 
235 	if (test_bit(NFS_CS_DS, &cl_init->init_flags))
236 		__set_bit(NFS_CS_DS, &clp->cl_flags);
237 	/*
238 	 * Set up the connection to the server before we add add to the
239 	 * global list.
240 	 */
241 	err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_GSS_KRB5I);
242 	if (err == -EINVAL)
243 		err = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
244 	if (err < 0)
245 		goto error;
246 
247 	/* If no clientaddr= option was specified, find a usable cb address */
248 	if (ip_addr == NULL) {
249 		struct sockaddr_storage cb_addr;
250 		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
251 
252 		err = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
253 		if (err < 0)
254 			goto error;
255 		err = rpc_ntop(sap, buf, sizeof(buf));
256 		if (err < 0)
257 			goto error;
258 		ip_addr = (const char *)buf;
259 	}
260 	strscpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
261 
262 	err = nfs_idmap_new(clp);
263 	if (err < 0) {
264 		dprintk("%s: failed to create idmapper. Error = %d\n",
265 			__func__, err);
266 		goto error;
267 	}
268 	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
269 	return clp;
270 
271 error:
272 	nfs_free_client(clp);
273 	return ERR_PTR(err);
274 }
275 
276 /*
277  * Destroy the NFS4 callback service
278  */
279 static void nfs4_destroy_callback(struct nfs_client *clp)
280 {
281 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
282 		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
283 }
284 
285 static void nfs4_shutdown_client(struct nfs_client *clp)
286 {
287 	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
288 		nfs4_kill_renewd(clp);
289 	clp->cl_mvops->shutdown_client(clp);
290 	nfs4_destroy_callback(clp);
291 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
292 		nfs_idmap_delete(clp);
293 
294 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
295 	kfree(clp->cl_serverowner);
296 	kfree(clp->cl_serverscope);
297 	kfree(clp->cl_implid);
298 	kfree(clp->cl_owner_id);
299 }
300 
301 void nfs4_free_client(struct nfs_client *clp)
302 {
303 	nfs4_shutdown_client(clp);
304 	nfs_free_client(clp);
305 }
306 
307 /*
308  * Initialize the NFS4 callback service
309  */
310 static int nfs4_init_callback(struct nfs_client *clp)
311 {
312 	struct rpc_xprt *xprt;
313 	int error;
314 
315 	xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);
316 
317 	if (nfs4_has_session(clp)) {
318 		error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
319 		if (error < 0)
320 			return error;
321 	}
322 
323 	error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
324 	if (error < 0) {
325 		dprintk("%s: failed to start callback. Error = %d\n",
326 			__func__, error);
327 		return error;
328 	}
329 	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
330 
331 	return 0;
332 }
333 
334 /**
335  * nfs40_init_client - nfs_client initialization tasks for NFSv4.0
336  * @clp: nfs_client to initialize
337  *
338  * Returns zero on success, or a negative errno if some error occurred.
339  */
340 int nfs40_init_client(struct nfs_client *clp)
341 {
342 	struct nfs4_slot_table *tbl;
343 	int ret;
344 
345 	tbl = kzalloc(sizeof(*tbl), GFP_NOFS);
346 	if (tbl == NULL)
347 		return -ENOMEM;
348 
349 	ret = nfs4_setup_slot_table(tbl, NFS4_MAX_SLOT_TABLE,
350 					"NFSv4.0 transport Slot table");
351 	if (ret) {
352 		nfs4_shutdown_slot_table(tbl);
353 		kfree(tbl);
354 		return ret;
355 	}
356 
357 	clp->cl_slot_tbl = tbl;
358 	return 0;
359 }
360 
361 #if defined(CONFIG_NFS_V4_1)
362 
363 /**
364  * nfs41_init_client - nfs_client initialization tasks for NFSv4.1+
365  * @clp: nfs_client to initialize
366  *
367  * Returns zero on success, or a negative errno if some error occurred.
368  */
369 int nfs41_init_client(struct nfs_client *clp)
370 {
371 	struct nfs4_session *session = NULL;
372 
373 	/*
374 	 * Create the session and mark it expired.
375 	 * When a SEQUENCE operation encounters the expired session
376 	 * it will do session recovery to initialize it.
377 	 */
378 	session = nfs4_alloc_session(clp);
379 	if (!session)
380 		return -ENOMEM;
381 
382 	clp->cl_session = session;
383 
384 	/*
385 	 * The create session reply races with the server back
386 	 * channel probe. Mark the client NFS_CS_SESSION_INITING
387 	 * so that the client back channel can find the
388 	 * nfs_client struct
389 	 */
390 	nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
391 	return 0;
392 }
393 
394 #endif	/* CONFIG_NFS_V4_1 */
395 
396 /*
397  * Initialize the minor version specific parts of an NFS4 client record
398  */
399 static int nfs4_init_client_minor_version(struct nfs_client *clp)
400 {
401 	int ret;
402 
403 	ret = clp->cl_mvops->init_client(clp);
404 	if (ret)
405 		return ret;
406 	return nfs4_init_callback(clp);
407 }
408 
409 static void nfs4_add_trunk(struct nfs_client *clp, struct nfs_client *old)
410 {
411 	struct sockaddr_storage clp_addr, old_addr;
412 	struct sockaddr *clp_sap = (struct sockaddr *)&clp_addr;
413 	struct sockaddr *old_sap = (struct sockaddr *)&old_addr;
414 	size_t clp_salen;
415 	struct xprt_create xprt_args = {
416 		.ident = old->cl_proto,
417 		.net = old->cl_net,
418 		.servername = old->cl_hostname,
419 	};
420 	int max_connect = test_bit(NFS_CS_PNFS, &clp->cl_flags) ?
421 		clp->cl_max_connect : old->cl_max_connect;
422 
423 	if (clp->cl_proto != old->cl_proto)
424 		return;
425 	clp_salen = rpc_peeraddr(clp->cl_rpcclient, clp_sap, sizeof(clp_addr));
426 	rpc_peeraddr(old->cl_rpcclient, old_sap, sizeof(old_addr));
427 
428 	if (clp_addr.ss_family != old_addr.ss_family)
429 		return;
430 
431 	xprt_args.dstaddr = clp_sap;
432 	xprt_args.addrlen = clp_salen;
433 
434 	rpc_clnt_add_xprt(old->cl_rpcclient, &xprt_args,
435 			  rpc_clnt_test_and_add_xprt, &max_connect);
436 }
437 
438 /**
439  * nfs4_init_client - Initialise an NFS4 client record
440  *
441  * @clp: nfs_client to initialise
442  * @cl_init: pointer to nfs_client_initdata
443  *
444  * Returns pointer to an NFS client, or an ERR_PTR value.
445  */
446 struct nfs_client *nfs4_init_client(struct nfs_client *clp,
447 				    const struct nfs_client_initdata *cl_init)
448 {
449 	struct nfs_client *old;
450 	int error;
451 
452 	if (clp->cl_cons_state == NFS_CS_READY)
453 		/* the client is initialised already */
454 		return clp;
455 
456 	error = nfs4_init_client_minor_version(clp);
457 	if (error < 0)
458 		goto error;
459 
460 	error = nfs4_discover_server_trunking(clp, &old);
461 	if (error < 0)
462 		goto error;
463 
464 	if (clp != old) {
465 		clp->cl_preserve_clid = true;
466 		/*
467 		 * Mark the client as having failed initialization so other
468 		 * processes walking the nfs_client_list in nfs_match_client()
469 		 * won't try to use it.
470 		 */
471 		nfs_mark_client_ready(clp, -EPERM);
472 		if (old->cl_mvops->session_trunk)
473 			nfs4_add_trunk(clp, old);
474 	}
475 	clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
476 	nfs_put_client(clp);
477 	return old;
478 
479 error:
480 	nfs_mark_client_ready(clp, error);
481 	nfs_put_client(clp);
482 	return ERR_PTR(error);
483 }
484 
485 /*
486  * SETCLIENTID just did a callback update with the callback ident in
487  * "drop," but server trunking discovery claims "drop" and "keep" are
488  * actually the same server.  Swap the callback IDs so that "keep"
489  * will continue to use the callback ident the server now knows about,
490  * and so that "keep"'s original callback ident is destroyed when
491  * "drop" is freed.
492  */
493 static void nfs4_swap_callback_idents(struct nfs_client *keep,
494 				      struct nfs_client *drop)
495 {
496 	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
497 	unsigned int save = keep->cl_cb_ident;
498 
499 	if (keep->cl_cb_ident == drop->cl_cb_ident)
500 		return;
501 
502 	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
503 		__func__, keep->cl_cb_ident, drop->cl_cb_ident);
504 
505 	spin_lock(&nn->nfs_client_lock);
506 
507 	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
508 	keep->cl_cb_ident = drop->cl_cb_ident;
509 
510 	idr_replace(&nn->cb_ident_idr, drop, save);
511 	drop->cl_cb_ident = save;
512 
513 	spin_unlock(&nn->nfs_client_lock);
514 }
515 
516 static bool nfs4_match_client_owner_id(const struct nfs_client *clp1,
517 		const struct nfs_client *clp2)
518 {
519 	if (clp1->cl_owner_id == NULL || clp2->cl_owner_id == NULL)
520 		return true;
521 	return strcmp(clp1->cl_owner_id, clp2->cl_owner_id) == 0;
522 }
523 
524 static bool nfs4_same_verifier(nfs4_verifier *v1, nfs4_verifier *v2)
525 {
526 	return memcmp(v1->data, v2->data, sizeof(v1->data)) == 0;
527 }
528 
529 static int nfs4_match_client(struct nfs_client  *pos,  struct nfs_client *new,
530 			     struct nfs_client **prev, struct nfs_net *nn)
531 {
532 	int status;
533 
534 	if (pos->rpc_ops != new->rpc_ops)
535 		return 1;
536 
537 	if (pos->cl_minorversion != new->cl_minorversion)
538 		return 1;
539 
540 	/* If "pos" isn't marked ready, we can't trust the
541 	 * remaining fields in "pos", especially the client
542 	 * ID and serverowner fields.  Wait for CREATE_SESSION
543 	 * to finish. */
544 	if (pos->cl_cons_state > NFS_CS_READY) {
545 		refcount_inc(&pos->cl_count);
546 		spin_unlock(&nn->nfs_client_lock);
547 
548 		nfs_put_client(*prev);
549 		*prev = pos;
550 
551 		status = nfs_wait_client_init_complete(pos);
552 		spin_lock(&nn->nfs_client_lock);
553 
554 		if (status < 0)
555 			return status;
556 	}
557 
558 	if (pos->cl_cons_state != NFS_CS_READY)
559 		return 1;
560 
561 	if (pos->cl_clientid != new->cl_clientid)
562 		return 1;
563 
564 	/* NFSv4.1 always uses the uniform string, however someone
565 	 * might switch the uniquifier string on us.
566 	 */
567 	if (!nfs4_match_client_owner_id(pos, new))
568 		return 1;
569 
570 	return 0;
571 }
572 
573 /**
574  * nfs40_walk_client_list - Find server that recognizes a client ID
575  *
576  * @new: nfs_client with client ID to test
577  * @result: OUT: found nfs_client, or new
578  * @cred: credential to use for trunking test
579  *
580  * Returns zero, a negative errno, or a negative NFS4ERR status.
581  * If zero is returned, an nfs_client pointer is planted in "result."
582  *
583  * NB: nfs40_walk_client_list() relies on the new nfs_client being
584  *     the last nfs_client on the list.
585  */
586 int nfs40_walk_client_list(struct nfs_client *new,
587 			   struct nfs_client **result,
588 			   const struct cred *cred)
589 {
590 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
591 	struct nfs_client *pos, *prev = NULL;
592 	struct nfs4_setclientid_res clid = {
593 		.clientid	= new->cl_clientid,
594 		.confirm	= new->cl_confirm,
595 	};
596 	int status = -NFS4ERR_STALE_CLIENTID;
597 
598 	spin_lock(&nn->nfs_client_lock);
599 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
600 
601 		if (pos == new)
602 			goto found;
603 
604 		status = nfs4_match_client(pos, new, &prev, nn);
605 		if (status < 0)
606 			goto out_unlock;
607 		if (status != 0)
608 			continue;
609 		/*
610 		 * We just sent a new SETCLIENTID, which should have
611 		 * caused the server to return a new cl_confirm.  So if
612 		 * cl_confirm is the same, then this is a different
613 		 * server that just returned the same cl_confirm by
614 		 * coincidence:
615 		 */
616 		if ((new != pos) && nfs4_same_verifier(&pos->cl_confirm,
617 						       &new->cl_confirm))
618 			continue;
619 		/*
620 		 * But if the cl_confirm's are different, then the only
621 		 * way that a SETCLIENTID_CONFIRM to pos can succeed is
622 		 * if new and pos point to the same server:
623 		 */
624 found:
625 		refcount_inc(&pos->cl_count);
626 		spin_unlock(&nn->nfs_client_lock);
627 
628 		nfs_put_client(prev);
629 		prev = pos;
630 
631 		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
632 		switch (status) {
633 		case -NFS4ERR_STALE_CLIENTID:
634 			break;
635 		case 0:
636 			nfs4_swap_callback_idents(pos, new);
637 			pos->cl_confirm = new->cl_confirm;
638 			nfs_mark_client_ready(pos, NFS_CS_READY);
639 
640 			prev = NULL;
641 			*result = pos;
642 			goto out;
643 		case -ERESTARTSYS:
644 		case -ETIMEDOUT:
645 			/* The callback path may have been inadvertently
646 			 * changed. Schedule recovery!
647 			 */
648 			nfs4_schedule_path_down_recovery(pos);
649 			goto out;
650 		default:
651 			goto out;
652 		}
653 
654 		spin_lock(&nn->nfs_client_lock);
655 	}
656 out_unlock:
657 	spin_unlock(&nn->nfs_client_lock);
658 
659 	/* No match found. The server lost our clientid */
660 out:
661 	nfs_put_client(prev);
662 	return status;
663 }
664 
665 #ifdef CONFIG_NFS_V4_1
666 /*
667  * Returns true if the server major ids match
668  */
669 bool
670 nfs4_check_serverowner_major_id(struct nfs41_server_owner *o1,
671 				struct nfs41_server_owner *o2)
672 {
673 	if (o1->major_id_sz != o2->major_id_sz)
674 		return false;
675 	return memcmp(o1->major_id, o2->major_id, o1->major_id_sz) == 0;
676 }
677 
678 /*
679  * Returns true if the server scopes match
680  */
681 static bool
682 nfs4_check_server_scope(struct nfs41_server_scope *s1,
683 			struct nfs41_server_scope *s2)
684 {
685 	if (s1->server_scope_sz != s2->server_scope_sz)
686 		return false;
687 	return memcmp(s1->server_scope, s2->server_scope,
688 					s1->server_scope_sz) == 0;
689 }
690 
691 /**
692  * nfs4_detect_session_trunking - Checks for session trunking.
693  * @clp:    original mount nfs_client
694  * @res:    result structure from an exchange_id using the original mount
695  *          nfs_client with a new multi_addr transport
696  * @xprt:   pointer to the transport to add.
697  *
698  * Called after a successful EXCHANGE_ID on a multi-addr connection.
699  * Upon success, add the transport.
700  *
701  * Returns zero on success, otherwise -EINVAL
702  *
703  * Note: since the exchange_id for the new multi_addr transport uses the
704  * same nfs_client from the original mount, the cl_owner_id is reused,
705  * so eir_clientowner is the same.
706  */
707 int nfs4_detect_session_trunking(struct nfs_client *clp,
708 				 struct nfs41_exchange_id_res *res,
709 				 struct rpc_xprt *xprt)
710 {
711 	/* Check eir_clientid */
712 	if (clp->cl_clientid != res->clientid)
713 		goto out_err;
714 
715 	/* Check eir_server_owner so_major_id */
716 	if (!nfs4_check_serverowner_major_id(clp->cl_serverowner,
717 					     res->server_owner))
718 		goto out_err;
719 
720 	/* Check eir_server_owner so_minor_id */
721 	if (clp->cl_serverowner->minor_id != res->server_owner->minor_id)
722 		goto out_err;
723 
724 	/* Check eir_server_scope */
725 	if (!nfs4_check_server_scope(clp->cl_serverscope, res->server_scope))
726 		goto out_err;
727 
728 	pr_info("NFS:  %s: Session trunking succeeded for %s\n",
729 		clp->cl_hostname,
730 		xprt->address_strings[RPC_DISPLAY_ADDR]);
731 
732 	return 0;
733 out_err:
734 	pr_info("NFS:  %s: Session trunking failed for %s\n", clp->cl_hostname,
735 		xprt->address_strings[RPC_DISPLAY_ADDR]);
736 
737 	return -EINVAL;
738 }
739 
740 /**
741  * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
742  *
743  * @new: nfs_client with client ID to test
744  * @result: OUT: found nfs_client, or new
745  * @cred: credential to use for trunking test
746  *
747  * Returns zero, a negative errno, or a negative NFS4ERR status.
748  * If zero is returned, an nfs_client pointer is planted in "result."
749  *
750  * NB: nfs41_walk_client_list() relies on the new nfs_client being
751  *     the last nfs_client on the list.
752  */
753 int nfs41_walk_client_list(struct nfs_client *new,
754 			   struct nfs_client **result,
755 			   const struct cred *cred)
756 {
757 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
758 	struct nfs_client *pos, *prev = NULL;
759 	int status = -NFS4ERR_STALE_CLIENTID;
760 
761 	spin_lock(&nn->nfs_client_lock);
762 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
763 
764 		if (pos == new)
765 			goto found;
766 
767 		status = nfs4_match_client(pos, new, &prev, nn);
768 		if (status < 0)
769 			goto out;
770 		if (status != 0)
771 			continue;
772 
773 		/*
774 		 * Note that session trunking is just a special subcase of
775 		 * client id trunking. In either case, we want to fall back
776 		 * to using the existing nfs_client.
777 		 */
778 		if (!nfs4_check_serverowner_major_id(pos->cl_serverowner,
779 						     new->cl_serverowner))
780 			continue;
781 
782 found:
783 		refcount_inc(&pos->cl_count);
784 		*result = pos;
785 		status = 0;
786 		break;
787 	}
788 
789 out:
790 	spin_unlock(&nn->nfs_client_lock);
791 	nfs_put_client(prev);
792 	return status;
793 }
794 #endif	/* CONFIG_NFS_V4_1 */
795 
796 static void nfs4_destroy_server(struct nfs_server *server)
797 {
798 	LIST_HEAD(freeme);
799 
800 	nfs_server_return_all_delegations(server);
801 	unset_pnfs_layoutdriver(server);
802 	nfs4_purge_state_owners(server, &freeme);
803 	nfs4_free_state_owners(&freeme);
804 }
805 
806 /*
807  * NFSv4.0 callback thread helper
808  *
809  * Find a client by callback identifier
810  */
811 struct nfs_client *
812 nfs4_find_client_ident(struct net *net, int cb_ident)
813 {
814 	struct nfs_client *clp;
815 	struct nfs_net *nn = net_generic(net, nfs_net_id);
816 
817 	spin_lock(&nn->nfs_client_lock);
818 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
819 	if (clp)
820 		refcount_inc(&clp->cl_count);
821 	spin_unlock(&nn->nfs_client_lock);
822 	return clp;
823 }
824 
825 #if defined(CONFIG_NFS_V4_1)
826 /* Common match routine for v4.0 and v4.1 callback services */
827 static bool nfs4_cb_match_client(const struct sockaddr *addr,
828 		struct nfs_client *clp, u32 minorversion)
829 {
830 	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
831 
832 	/* Don't match clients that failed to initialise */
833 	if (!(clp->cl_cons_state == NFS_CS_READY ||
834 	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
835 		return false;
836 
837 	smp_rmb();
838 
839 	/* Match the version and minorversion */
840 	if (clp->rpc_ops->version != 4 ||
841 	    clp->cl_minorversion != minorversion)
842 		return false;
843 
844 	/* Match only the IP address, not the port number */
845 	return rpc_cmp_addr(addr, clap);
846 }
847 
848 /*
849  * NFSv4.1 callback thread helper
850  * For CB_COMPOUND calls, find a client by IP address, protocol version,
851  * minorversion, and sessionID
852  *
853  * Returns NULL if no such client
854  */
855 struct nfs_client *
856 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
857 			   struct nfs4_sessionid *sid, u32 minorversion)
858 {
859 	struct nfs_client *clp;
860 	struct nfs_net *nn = net_generic(net, nfs_net_id);
861 
862 	spin_lock(&nn->nfs_client_lock);
863 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
864 		if (!nfs4_cb_match_client(addr, clp, minorversion))
865 			continue;
866 
867 		if (!nfs4_has_session(clp))
868 			continue;
869 
870 		/* Match sessionid*/
871 		if (memcmp(clp->cl_session->sess_id.data,
872 		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
873 			continue;
874 
875 		refcount_inc(&clp->cl_count);
876 		spin_unlock(&nn->nfs_client_lock);
877 		return clp;
878 	}
879 	spin_unlock(&nn->nfs_client_lock);
880 	return NULL;
881 }
882 
883 #else /* CONFIG_NFS_V4_1 */
884 
885 struct nfs_client *
886 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
887 			   struct nfs4_sessionid *sid, u32 minorversion)
888 {
889 	return NULL;
890 }
891 #endif /* CONFIG_NFS_V4_1 */
892 
893 /*
894  * Set up an NFS4 client
895  */
896 static int nfs4_set_client(struct nfs_server *server,
897 		const char *hostname,
898 		const struct sockaddr_storage *addr,
899 		const size_t addrlen,
900 		const char *ip_addr,
901 		int proto, const struct rpc_timeout *timeparms,
902 		u32 minorversion, unsigned int nconnect,
903 		unsigned int max_connect,
904 		struct net *net,
905 		struct xprtsec_parms *xprtsec)
906 {
907 	struct nfs_client_initdata cl_init = {
908 		.hostname = hostname,
909 		.addr = addr,
910 		.addrlen = addrlen,
911 		.ip_addr = ip_addr,
912 		.nfs_mod = &nfs_v4,
913 		.proto = proto,
914 		.minorversion = minorversion,
915 		.net = net,
916 		.timeparms = timeparms,
917 		.cred = server->cred,
918 		.xprtsec = *xprtsec,
919 	};
920 	struct nfs_client *clp;
921 
922 	if (minorversion == 0)
923 		__set_bit(NFS_CS_REUSEPORT, &cl_init.init_flags);
924 	else
925 		cl_init.max_connect = max_connect;
926 	switch (proto) {
927 	case XPRT_TRANSPORT_RDMA:
928 	case XPRT_TRANSPORT_TCP:
929 	case XPRT_TRANSPORT_TCP_TLS:
930 		cl_init.nconnect = nconnect;
931 	}
932 
933 	if (server->flags & NFS_MOUNT_NORESVPORT)
934 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
935 	if (server->options & NFS_OPTION_MIGRATION)
936 		__set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
937 	if (test_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status))
938 		__set_bit(NFS_CS_TSM_POSSIBLE, &cl_init.init_flags);
939 	server->port = rpc_get_port((struct sockaddr *)addr);
940 
941 	/* Allocate or find a client reference we can use */
942 	clp = nfs_get_client(&cl_init);
943 	if (IS_ERR(clp))
944 		return PTR_ERR(clp);
945 
946 	if (server->nfs_client == clp) {
947 		nfs_put_client(clp);
948 		return -ELOOP;
949 	}
950 
951 	/*
952 	 * Query for the lease time on clientid setup or renewal
953 	 *
954 	 * Note that this will be set on nfs_clients that were created
955 	 * only for the DS role and did not set this bit, but now will
956 	 * serve a dual role.
957 	 */
958 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
959 
960 	server->nfs_client = clp;
961 	nfs_sysfs_add_server(server);
962 	nfs_sysfs_link_rpc_client(server, clp->cl_rpcclient, "_state");
963 
964 	return 0;
965 }
966 
967 /*
968  * Set up a pNFS Data Server client.
969  *
970  * Return any existing nfs_client that matches server address,port,version
971  * and minorversion.
972  *
973  * For a new nfs_client, use a soft mount (default), a low retrans and a
974  * low timeout interval so that if a connection is lost, we retry through
975  * the MDS.
976  */
977 struct nfs_client *nfs4_set_ds_client(struct nfs_server *mds_srv,
978 		const struct sockaddr_storage *ds_addr, int ds_addrlen,
979 		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans,
980 		u32 minor_version)
981 {
982 	struct rpc_timeout ds_timeout;
983 	struct nfs_client *mds_clp = mds_srv->nfs_client;
984 	struct nfs_client_initdata cl_init = {
985 		.addr = ds_addr,
986 		.addrlen = ds_addrlen,
987 		.nodename = mds_clp->cl_rpcclient->cl_nodename,
988 		.ip_addr = mds_clp->cl_ipaddr,
989 		.nfs_mod = &nfs_v4,
990 		.proto = ds_proto,
991 		.minorversion = minor_version,
992 		.net = mds_clp->cl_net,
993 		.timeparms = &ds_timeout,
994 		.cred = mds_srv->cred,
995 		.xprtsec = mds_srv->nfs_client->cl_xprtsec,
996 	};
997 	char buf[INET6_ADDRSTRLEN + 1];
998 
999 	if (rpc_ntop((struct sockaddr *)ds_addr, buf, sizeof(buf)) <= 0)
1000 		return ERR_PTR(-EINVAL);
1001 	cl_init.hostname = buf;
1002 
1003 	switch (ds_proto) {
1004 	case XPRT_TRANSPORT_RDMA:
1005 	case XPRT_TRANSPORT_TCP:
1006 	case XPRT_TRANSPORT_TCP_TLS:
1007 		if (mds_clp->cl_nconnect > 1) {
1008 			cl_init.nconnect = mds_clp->cl_nconnect;
1009 			cl_init.max_connect = NFS_MAX_TRANSPORTS;
1010 		}
1011 	}
1012 
1013 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
1014 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
1015 
1016 	__set_bit(NFS_CS_DS, &cl_init.init_flags);
1017 	__set_bit(NFS_CS_PNFS, &cl_init.init_flags);
1018 	cl_init.max_connect = NFS_MAX_TRANSPORTS;
1019 	/*
1020 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
1021 	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
1022 	 * (section 13.1 RFC 5661).
1023 	 */
1024 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
1025 	return nfs_get_client(&cl_init);
1026 }
1027 EXPORT_SYMBOL_GPL(nfs4_set_ds_client);
1028 
1029 /*
1030  * Session has been established, and the client marked ready.
1031  * Limit the mount rsize, wsize and dtsize using negotiated fore
1032  * channel attributes.
1033  */
1034 static void nfs4_session_limit_rwsize(struct nfs_server *server)
1035 {
1036 #ifdef CONFIG_NFS_V4_1
1037 	struct nfs4_session *sess;
1038 	u32 server_resp_sz;
1039 	u32 server_rqst_sz;
1040 
1041 	if (!nfs4_has_session(server->nfs_client))
1042 		return;
1043 	sess = server->nfs_client->cl_session;
1044 	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
1045 	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
1046 
1047 	if (server->dtsize > server_resp_sz)
1048 		server->dtsize = server_resp_sz;
1049 	if (server->rsize > server_resp_sz)
1050 		server->rsize = server_resp_sz;
1051 	if (server->wsize > server_rqst_sz)
1052 		server->wsize = server_rqst_sz;
1053 #endif /* CONFIG_NFS_V4_1 */
1054 }
1055 
1056 /*
1057  * Limit xattr sizes using the channel attributes.
1058  */
1059 static void nfs4_session_limit_xasize(struct nfs_server *server)
1060 {
1061 #ifdef CONFIG_NFS_V4_2
1062 	struct nfs4_session *sess;
1063 	u32 server_gxa_sz;
1064 	u32 server_sxa_sz;
1065 	u32 server_lxa_sz;
1066 
1067 	if (!nfs4_has_session(server->nfs_client))
1068 		return;
1069 
1070 	sess = server->nfs_client->cl_session;
1071 
1072 	server_gxa_sz = sess->fc_attrs.max_resp_sz - nfs42_maxgetxattr_overhead;
1073 	server_sxa_sz = sess->fc_attrs.max_rqst_sz - nfs42_maxsetxattr_overhead;
1074 	server_lxa_sz = sess->fc_attrs.max_resp_sz -
1075 	    nfs42_maxlistxattrs_overhead;
1076 
1077 	if (server->gxasize > server_gxa_sz)
1078 		server->gxasize = server_gxa_sz;
1079 	if (server->sxasize > server_sxa_sz)
1080 		server->sxasize = server_sxa_sz;
1081 	if (server->lxasize > server_lxa_sz)
1082 		server->lxasize = server_lxa_sz;
1083 #endif
1084 }
1085 
1086 void nfs4_server_set_init_caps(struct nfs_server *server)
1087 {
1088 	/* Set the basic capabilities */
1089 	server->caps |= server->nfs_client->cl_mvops->init_caps;
1090 	if (server->flags & NFS_MOUNT_NORDIRPLUS)
1091 			server->caps &= ~NFS_CAP_READDIRPLUS;
1092 	if (server->nfs_client->cl_proto == XPRT_TRANSPORT_RDMA)
1093 		server->caps &= ~NFS_CAP_READ_PLUS;
1094 
1095 	/*
1096 	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
1097 	 * authentication.
1098 	 */
1099 	if (nfs4_disable_idmapping &&
1100 			server->client->cl_auth->au_flavor == RPC_AUTH_UNIX)
1101 		server->caps |= NFS_CAP_UIDGID_NOMAP;
1102 }
1103 
1104 static int nfs4_server_common_setup(struct nfs_server *server,
1105 		struct nfs_fh *mntfh, bool auth_probe)
1106 {
1107 	int error;
1108 
1109 	/* data servers support only a subset of NFSv4.1 */
1110 	if (is_ds_only_client(server->nfs_client))
1111 		return -EPROTONOSUPPORT;
1112 
1113 	/* We must ensure the session is initialised first */
1114 	error = nfs4_init_session(server->nfs_client);
1115 	if (error < 0)
1116 		goto out;
1117 
1118 	nfs4_server_set_init_caps(server);
1119 
1120 	/* Probe the root fh to retrieve its FSID and filehandle */
1121 	error = nfs4_get_rootfh(server, mntfh, auth_probe);
1122 	if (error < 0)
1123 		goto out;
1124 
1125 	dprintk("Server FSID: %llx:%llx\n",
1126 			(unsigned long long) server->fsid.major,
1127 			(unsigned long long) server->fsid.minor);
1128 	nfs_display_fhandle(mntfh, "Pseudo-fs root FH");
1129 
1130 	error = nfs_probe_server(server, mntfh);
1131 	if (error < 0)
1132 		goto out;
1133 
1134 	nfs4_session_limit_rwsize(server);
1135 	nfs4_session_limit_xasize(server);
1136 
1137 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
1138 		server->namelen = NFS4_MAXNAMLEN;
1139 
1140 	nfs_server_insert_lists(server);
1141 	server->mount_time = jiffies;
1142 	server->destroy = nfs4_destroy_server;
1143 out:
1144 	return error;
1145 }
1146 
1147 /*
1148  * Create a version 4 volume record
1149  */
1150 static int nfs4_init_server(struct nfs_server *server, struct fs_context *fc)
1151 {
1152 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1153 	struct rpc_timeout timeparms;
1154 	int error;
1155 
1156 	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
1157 				ctx->timeo, ctx->retrans);
1158 
1159 	/* Initialise the client representation from the mount data */
1160 	server->flags = ctx->flags;
1161 	server->options = ctx->options;
1162 	server->auth_info = ctx->auth_info;
1163 
1164 	/* Use the first specified auth flavor. If this flavor isn't
1165 	 * allowed by the server, use the SECINFO path to try the
1166 	 * other specified flavors */
1167 	if (ctx->auth_info.flavor_len >= 1)
1168 		ctx->selected_flavor = ctx->auth_info.flavors[0];
1169 	else
1170 		ctx->selected_flavor = RPC_AUTH_UNIX;
1171 
1172 	/* Get a client record */
1173 	error = nfs4_set_client(server,
1174 				ctx->nfs_server.hostname,
1175 				&ctx->nfs_server._address,
1176 				ctx->nfs_server.addrlen,
1177 				ctx->client_address,
1178 				ctx->nfs_server.protocol,
1179 				&timeparms,
1180 				ctx->minorversion,
1181 				ctx->nfs_server.nconnect,
1182 				ctx->nfs_server.max_connect,
1183 				fc->net_ns,
1184 				&ctx->xprtsec);
1185 	if (error < 0)
1186 		return error;
1187 
1188 	if (ctx->rsize)
1189 		server->rsize = nfs_io_size(ctx->rsize, server->nfs_client->cl_proto);
1190 	if (ctx->wsize)
1191 		server->wsize = nfs_io_size(ctx->wsize, server->nfs_client->cl_proto);
1192 
1193 	server->acregmin = ctx->acregmin * HZ;
1194 	server->acregmax = ctx->acregmax * HZ;
1195 	server->acdirmin = ctx->acdirmin * HZ;
1196 	server->acdirmax = ctx->acdirmax * HZ;
1197 	server->port     = ctx->nfs_server.port;
1198 
1199 	return nfs_init_server_rpcclient(server, &timeparms,
1200 					 ctx->selected_flavor);
1201 }
1202 
1203 /*
1204  * Create a version 4 volume record
1205  * - keyed on server and FSID
1206  */
1207 struct nfs_server *nfs4_create_server(struct fs_context *fc)
1208 {
1209 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1210 	struct nfs_server *server;
1211 	bool auth_probe;
1212 	int error;
1213 
1214 	server = nfs_alloc_server();
1215 	if (!server)
1216 		return ERR_PTR(-ENOMEM);
1217 
1218 	server->cred = get_cred(fc->cred);
1219 
1220 	auth_probe = ctx->auth_info.flavor_len < 1;
1221 
1222 	/* set up the general RPC client */
1223 	error = nfs4_init_server(server, fc);
1224 	if (error < 0)
1225 		goto error;
1226 
1227 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1228 	if (error < 0)
1229 		goto error;
1230 
1231 	return server;
1232 
1233 error:
1234 	nfs_free_server(server);
1235 	return ERR_PTR(error);
1236 }
1237 
1238 /*
1239  * Create an NFS4 referral server record
1240  */
1241 struct nfs_server *nfs4_create_referral_server(struct fs_context *fc)
1242 {
1243 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1244 	struct nfs_client *parent_client;
1245 	struct nfs_server *server, *parent_server;
1246 	int proto, error;
1247 	bool auth_probe;
1248 
1249 	server = nfs_alloc_server();
1250 	if (!server)
1251 		return ERR_PTR(-ENOMEM);
1252 
1253 	parent_server = NFS_SB(ctx->clone_data.sb);
1254 	parent_client = parent_server->nfs_client;
1255 
1256 	server->cred = get_cred(parent_server->cred);
1257 
1258 	/* Initialise the client representation from the parent server */
1259 	nfs_server_copy_userdata(server, parent_server);
1260 
1261 	/* Get a client representation */
1262 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1263 	rpc_set_port(&ctx->nfs_server.address, NFS_RDMA_PORT);
1264 	error = nfs4_set_client(server,
1265 				ctx->nfs_server.hostname,
1266 				&ctx->nfs_server._address,
1267 				ctx->nfs_server.addrlen,
1268 				parent_client->cl_ipaddr,
1269 				XPRT_TRANSPORT_RDMA,
1270 				parent_server->client->cl_timeout,
1271 				parent_client->cl_mvops->minor_version,
1272 				parent_client->cl_nconnect,
1273 				parent_client->cl_max_connect,
1274 				parent_client->cl_net,
1275 				&parent_client->cl_xprtsec);
1276 	if (!error)
1277 		goto init_server;
1278 #endif	/* IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA) */
1279 
1280 	proto = XPRT_TRANSPORT_TCP;
1281 	if (parent_client->cl_xprtsec.policy != RPC_XPRTSEC_NONE)
1282 		proto = XPRT_TRANSPORT_TCP_TLS;
1283 	rpc_set_port(&ctx->nfs_server.address, NFS_PORT);
1284 	error = nfs4_set_client(server,
1285 				ctx->nfs_server.hostname,
1286 				&ctx->nfs_server._address,
1287 				ctx->nfs_server.addrlen,
1288 				parent_client->cl_ipaddr,
1289 				proto,
1290 				parent_server->client->cl_timeout,
1291 				parent_client->cl_mvops->minor_version,
1292 				parent_client->cl_nconnect,
1293 				parent_client->cl_max_connect,
1294 				parent_client->cl_net,
1295 				&parent_client->cl_xprtsec);
1296 	if (error < 0)
1297 		goto error;
1298 
1299 #if IS_ENABLED(CONFIG_SUNRPC_XPRT_RDMA)
1300 init_server:
1301 #endif
1302 	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout,
1303 					  ctx->selected_flavor);
1304 	if (error < 0)
1305 		goto error;
1306 
1307 	auth_probe = parent_server->auth_info.flavor_len < 1;
1308 
1309 	error = nfs4_server_common_setup(server, ctx->mntfh, auth_probe);
1310 	if (error < 0)
1311 		goto error;
1312 
1313 	return server;
1314 
1315 error:
1316 	nfs_free_server(server);
1317 	return ERR_PTR(error);
1318 }
1319 
1320 /**
1321  * nfs4_update_server - Move an nfs_server to a different nfs_client
1322  *
1323  * @server: represents FSID to be moved
1324  * @hostname: new end-point's hostname
1325  * @sap: new end-point's socket address
1326  * @salen: size of "sap"
1327  * @net: net namespace
1328  *
1329  * The nfs_server must be quiescent before this function is invoked.
1330  * Either its session is drained (NFSv4.1+), or its transport is
1331  * plugged and drained (NFSv4.0).
1332  *
1333  * Returns zero on success, or a negative errno value.
1334  */
1335 int nfs4_update_server(struct nfs_server *server, const char *hostname,
1336 		       struct sockaddr_storage *sap, size_t salen, struct net *net)
1337 {
1338 	struct nfs_client *clp = server->nfs_client;
1339 	struct rpc_clnt *clnt = server->client;
1340 	struct xprt_create xargs = {
1341 		.ident		= clp->cl_proto,
1342 		.net		= net,
1343 		.dstaddr	= (struct sockaddr *)sap,
1344 		.addrlen	= salen,
1345 		.servername	= hostname,
1346 		/* cel: bleh. We might need to pass TLS parameters here */
1347 	};
1348 	char buf[INET6_ADDRSTRLEN + 1];
1349 	struct sockaddr_storage address;
1350 	struct sockaddr *localaddr = (struct sockaddr *)&address;
1351 	int error;
1352 
1353 	error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
1354 	if (error != 0)
1355 		return error;
1356 
1357 	error = rpc_localaddr(clnt, localaddr, sizeof(address));
1358 	if (error != 0)
1359 		return error;
1360 
1361 	if (rpc_ntop(localaddr, buf, sizeof(buf)) == 0)
1362 		return -EAFNOSUPPORT;
1363 
1364 	nfs_server_remove_lists(server);
1365 	set_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1366 	error = nfs4_set_client(server, hostname, sap, salen, buf,
1367 				clp->cl_proto, clnt->cl_timeout,
1368 				clp->cl_minorversion,
1369 				clp->cl_nconnect, clp->cl_max_connect,
1370 				net, &clp->cl_xprtsec);
1371 	clear_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
1372 	if (error != 0) {
1373 		nfs_server_insert_lists(server);
1374 		return error;
1375 	}
1376 	nfs_put_client(clp);
1377 
1378 	if (server->nfs_client->cl_hostname == NULL) {
1379 		server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
1380 		if (server->nfs_client->cl_hostname == NULL)
1381 			return -ENOMEM;
1382 	}
1383 	nfs_server_insert_lists(server);
1384 
1385 	return nfs_probe_server(server, NFS_FH(d_inode(server->super->s_root)));
1386 }
1387