xref: /openbmc/linux/fs/nfs/nfs4client.c (revision bc5aa3a0)
1 /*
2  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
3  * Written by David Howells (dhowells@redhat.com)
4  */
5 #include <linux/module.h>
6 #include <linux/nfs_fs.h>
7 #include <linux/nfs_mount.h>
8 #include <linux/sunrpc/addr.h>
9 #include <linux/sunrpc/auth.h>
10 #include <linux/sunrpc/xprt.h>
11 #include <linux/sunrpc/bc_xprt.h>
12 #include <linux/sunrpc/rpc_pipe_fs.h>
13 #include "internal.h"
14 #include "callback.h"
15 #include "delegation.h"
16 #include "nfs4session.h"
17 #include "nfs4idmap.h"
18 #include "pnfs.h"
19 #include "netns.h"
20 
21 #define NFSDBG_FACILITY		NFSDBG_CLIENT
22 
23 /*
24  * Get a unique NFSv4.0 callback identifier which will be used
25  * by the V4.0 callback service to lookup the nfs_client struct
26  */
27 static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
28 {
29 	int ret = 0;
30 	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
31 
32 	if (clp->rpc_ops->version != 4 || minorversion != 0)
33 		return ret;
34 	idr_preload(GFP_KERNEL);
35 	spin_lock(&nn->nfs_client_lock);
36 	ret = idr_alloc(&nn->cb_ident_idr, clp, 1, 0, GFP_NOWAIT);
37 	if (ret >= 0)
38 		clp->cl_cb_ident = ret;
39 	spin_unlock(&nn->nfs_client_lock);
40 	idr_preload_end();
41 	return ret < 0 ? ret : 0;
42 }
43 
44 #ifdef CONFIG_NFS_V4_1
45 /**
46  * Per auth flavor data server rpc clients
47  */
48 struct nfs4_ds_server {
49 	struct list_head	list;   /* ds_clp->cl_ds_clients */
50 	struct rpc_clnt		*rpc_clnt;
51 };
52 
53 /**
54  * Common lookup case for DS I/O
55  */
56 static struct nfs4_ds_server *
57 nfs4_find_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
58 {
59 	struct nfs4_ds_server *dss;
60 
61 	rcu_read_lock();
62 	list_for_each_entry_rcu(dss, &ds_clp->cl_ds_clients, list) {
63 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
64 			continue;
65 		goto out;
66 	}
67 	dss = NULL;
68 out:
69 	rcu_read_unlock();
70 	return dss;
71 }
72 
73 static struct nfs4_ds_server *
74 nfs4_add_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor,
75 			   struct nfs4_ds_server *new)
76 {
77 	struct nfs4_ds_server *dss;
78 
79 	spin_lock(&ds_clp->cl_lock);
80 	list_for_each_entry(dss, &ds_clp->cl_ds_clients, list) {
81 		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
82 			continue;
83 		goto out;
84 	}
85 	if (new)
86 		list_add_rcu(&new->list, &ds_clp->cl_ds_clients);
87 	dss = new;
88 out:
89 	spin_unlock(&ds_clp->cl_lock); /* need some lock to protect list */
90 	return dss;
91 }
92 
93 static struct nfs4_ds_server *
94 nfs4_alloc_ds_server(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
95 {
96 	struct nfs4_ds_server *dss;
97 
98 	dss = kmalloc(sizeof(*dss), GFP_NOFS);
99 	if (dss == NULL)
100 		return ERR_PTR(-ENOMEM);
101 
102 	dss->rpc_clnt = rpc_clone_client_set_auth(ds_clp->cl_rpcclient, flavor);
103 	if (IS_ERR(dss->rpc_clnt)) {
104 		int err = PTR_ERR(dss->rpc_clnt);
105 		kfree (dss);
106 		return ERR_PTR(err);
107 	}
108 	INIT_LIST_HEAD(&dss->list);
109 
110 	return dss;
111 }
112 
113 static void
114 nfs4_free_ds_server(struct nfs4_ds_server *dss)
115 {
116 	rpc_release_client(dss->rpc_clnt);
117 	kfree(dss);
118 }
119 
120 /**
121 * Find or create a DS rpc client with th MDS server rpc client auth flavor
122 * in the nfs_client cl_ds_clients list.
123 */
124 struct rpc_clnt *
125 nfs4_find_or_create_ds_client(struct nfs_client *ds_clp, struct inode *inode)
126 {
127 	struct nfs4_ds_server *dss, *new;
128 	rpc_authflavor_t flavor = NFS_SERVER(inode)->client->cl_auth->au_flavor;
129 
130 	dss = nfs4_find_ds_client(ds_clp, flavor);
131 	if (dss != NULL)
132 		goto out;
133 	new = nfs4_alloc_ds_server(ds_clp, flavor);
134 	if (IS_ERR(new))
135 		return ERR_CAST(new);
136 	dss = nfs4_add_ds_client(ds_clp, flavor, new);
137 	if (dss != new)
138 		nfs4_free_ds_server(new);
139 out:
140 	return dss->rpc_clnt;
141 }
142 EXPORT_SYMBOL_GPL(nfs4_find_or_create_ds_client);
143 
144 static void
145 nfs4_shutdown_ds_clients(struct nfs_client *clp)
146 {
147 	struct nfs4_ds_server *dss;
148 	LIST_HEAD(shutdown_list);
149 
150 	while (!list_empty(&clp->cl_ds_clients)) {
151 		dss = list_entry(clp->cl_ds_clients.next,
152 					struct nfs4_ds_server, list);
153 		list_del(&dss->list);
154 		rpc_shutdown_client(dss->rpc_clnt);
155 		kfree (dss);
156 	}
157 }
158 
159 void nfs41_shutdown_client(struct nfs_client *clp)
160 {
161 	if (nfs4_has_session(clp)) {
162 		nfs4_shutdown_ds_clients(clp);
163 		nfs4_destroy_session(clp->cl_session);
164 		nfs4_destroy_clientid(clp);
165 	}
166 
167 }
168 #endif	/* CONFIG_NFS_V4_1 */
169 
170 void nfs40_shutdown_client(struct nfs_client *clp)
171 {
172 	if (clp->cl_slot_tbl) {
173 		nfs4_shutdown_slot_table(clp->cl_slot_tbl);
174 		kfree(clp->cl_slot_tbl);
175 	}
176 }
177 
178 struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
179 {
180 	int err;
181 	struct nfs_client *clp = nfs_alloc_client(cl_init);
182 	if (IS_ERR(clp))
183 		return clp;
184 
185 	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
186 	if (err)
187 		goto error;
188 
189 	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
190 		err = -EINVAL;
191 		goto error;
192 	}
193 
194 	spin_lock_init(&clp->cl_lock);
195 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
196 	INIT_LIST_HEAD(&clp->cl_ds_clients);
197 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
198 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
199 	clp->cl_minorversion = cl_init->minorversion;
200 	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
201 	clp->cl_mig_gen = 1;
202 	return clp;
203 
204 error:
205 	nfs_free_client(clp);
206 	return ERR_PTR(err);
207 }
208 
209 /*
210  * Destroy the NFS4 callback service
211  */
212 static void nfs4_destroy_callback(struct nfs_client *clp)
213 {
214 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
215 		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
216 }
217 
218 static void nfs4_shutdown_client(struct nfs_client *clp)
219 {
220 	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
221 		nfs4_kill_renewd(clp);
222 	clp->cl_mvops->shutdown_client(clp);
223 	nfs4_destroy_callback(clp);
224 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
225 		nfs_idmap_delete(clp);
226 
227 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
228 	kfree(clp->cl_serverowner);
229 	kfree(clp->cl_serverscope);
230 	kfree(clp->cl_implid);
231 	kfree(clp->cl_owner_id);
232 }
233 
234 void nfs4_free_client(struct nfs_client *clp)
235 {
236 	nfs4_shutdown_client(clp);
237 	nfs_free_client(clp);
238 }
239 
240 /*
241  * Initialize the NFS4 callback service
242  */
243 static int nfs4_init_callback(struct nfs_client *clp)
244 {
245 	struct rpc_xprt *xprt;
246 	int error;
247 
248 	xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);
249 
250 	if (nfs4_has_session(clp)) {
251 		error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
252 		if (error < 0)
253 			return error;
254 	}
255 
256 	error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
257 	if (error < 0) {
258 		dprintk("%s: failed to start callback. Error = %d\n",
259 			__func__, error);
260 		return error;
261 	}
262 	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
263 
264 	return 0;
265 }
266 
267 /**
268  * nfs40_init_client - nfs_client initialization tasks for NFSv4.0
269  * @clp - nfs_client to initialize
270  *
271  * Returns zero on success, or a negative errno if some error occurred.
272  */
273 int nfs40_init_client(struct nfs_client *clp)
274 {
275 	struct nfs4_slot_table *tbl;
276 	int ret;
277 
278 	tbl = kzalloc(sizeof(*tbl), GFP_NOFS);
279 	if (tbl == NULL)
280 		return -ENOMEM;
281 
282 	ret = nfs4_setup_slot_table(tbl, NFS4_MAX_SLOT_TABLE,
283 					"NFSv4.0 transport Slot table");
284 	if (ret) {
285 		kfree(tbl);
286 		return ret;
287 	}
288 
289 	clp->cl_slot_tbl = tbl;
290 	return 0;
291 }
292 
293 #if defined(CONFIG_NFS_V4_1)
294 
295 /**
296  * nfs41_init_client - nfs_client initialization tasks for NFSv4.1+
297  * @clp - nfs_client to initialize
298  *
299  * Returns zero on success, or a negative errno if some error occurred.
300  */
301 int nfs41_init_client(struct nfs_client *clp)
302 {
303 	struct nfs4_session *session = NULL;
304 
305 	/*
306 	 * Create the session and mark it expired.
307 	 * When a SEQUENCE operation encounters the expired session
308 	 * it will do session recovery to initialize it.
309 	 */
310 	session = nfs4_alloc_session(clp);
311 	if (!session)
312 		return -ENOMEM;
313 
314 	clp->cl_session = session;
315 
316 	/*
317 	 * The create session reply races with the server back
318 	 * channel probe. Mark the client NFS_CS_SESSION_INITING
319 	 * so that the client back channel can find the
320 	 * nfs_client struct
321 	 */
322 	nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
323 	return 0;
324 }
325 
326 #endif	/* CONFIG_NFS_V4_1 */
327 
328 /*
329  * Initialize the minor version specific parts of an NFS4 client record
330  */
331 static int nfs4_init_client_minor_version(struct nfs_client *clp)
332 {
333 	int ret;
334 
335 	ret = clp->cl_mvops->init_client(clp);
336 	if (ret)
337 		return ret;
338 	return nfs4_init_callback(clp);
339 }
340 
341 /**
342  * nfs4_init_client - Initialise an NFS4 client record
343  *
344  * @clp: nfs_client to initialise
345  * @timeparms: timeout parameters for underlying RPC transport
346  * @ip_addr: callback IP address in presentation format
347  * @authflavor: authentication flavor for underlying RPC transport
348  *
349  * Returns pointer to an NFS client, or an ERR_PTR value.
350  */
351 struct nfs_client *nfs4_init_client(struct nfs_client *clp,
352 				    const struct nfs_client_initdata *cl_init)
353 {
354 	char buf[INET6_ADDRSTRLEN + 1];
355 	const char *ip_addr = cl_init->ip_addr;
356 	struct nfs_client *old;
357 	int error;
358 
359 	if (clp->cl_cons_state == NFS_CS_READY) {
360 		/* the client is initialised already */
361 		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
362 		return clp;
363 	}
364 
365 	/* Check NFS protocol revision and initialize RPC op vector */
366 	clp->rpc_ops = &nfs_v4_clientops;
367 
368 	if (clp->cl_minorversion != 0)
369 		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
370 	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
371 	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
372 
373 	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_GSS_KRB5I);
374 	if (error == -EINVAL)
375 		error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
376 	if (error < 0)
377 		goto error;
378 
379 	/* If no clientaddr= option was specified, find a usable cb address */
380 	if (ip_addr == NULL) {
381 		struct sockaddr_storage cb_addr;
382 		struct sockaddr *sap = (struct sockaddr *)&cb_addr;
383 
384 		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
385 		if (error < 0)
386 			goto error;
387 		error = rpc_ntop(sap, buf, sizeof(buf));
388 		if (error < 0)
389 			goto error;
390 		ip_addr = (const char *)buf;
391 	}
392 	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
393 
394 	error = nfs_idmap_new(clp);
395 	if (error < 0) {
396 		dprintk("%s: failed to create idmapper. Error = %d\n",
397 			__func__, error);
398 		goto error;
399 	}
400 	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);
401 
402 	error = nfs4_init_client_minor_version(clp);
403 	if (error < 0)
404 		goto error;
405 
406 	if (!nfs4_has_session(clp))
407 		nfs_mark_client_ready(clp, NFS_CS_READY);
408 
409 	error = nfs4_discover_server_trunking(clp, &old);
410 	if (error < 0)
411 		goto error;
412 
413 	if (clp != old)
414 		clp->cl_preserve_clid = true;
415 	nfs_put_client(clp);
416 	return old;
417 
418 error:
419 	nfs_mark_client_ready(clp, error);
420 	nfs_put_client(clp);
421 	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
422 	return ERR_PTR(error);
423 }
424 
425 /*
426  * SETCLIENTID just did a callback update with the callback ident in
427  * "drop," but server trunking discovery claims "drop" and "keep" are
428  * actually the same server.  Swap the callback IDs so that "keep"
429  * will continue to use the callback ident the server now knows about,
430  * and so that "keep"'s original callback ident is destroyed when
431  * "drop" is freed.
432  */
433 static void nfs4_swap_callback_idents(struct nfs_client *keep,
434 				      struct nfs_client *drop)
435 {
436 	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
437 	unsigned int save = keep->cl_cb_ident;
438 
439 	if (keep->cl_cb_ident == drop->cl_cb_ident)
440 		return;
441 
442 	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
443 		__func__, keep->cl_cb_ident, drop->cl_cb_ident);
444 
445 	spin_lock(&nn->nfs_client_lock);
446 
447 	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
448 	keep->cl_cb_ident = drop->cl_cb_ident;
449 
450 	idr_replace(&nn->cb_ident_idr, drop, save);
451 	drop->cl_cb_ident = save;
452 
453 	spin_unlock(&nn->nfs_client_lock);
454 }
455 
456 static bool nfs4_match_client_owner_id(const struct nfs_client *clp1,
457 		const struct nfs_client *clp2)
458 {
459 	if (clp1->cl_owner_id == NULL || clp2->cl_owner_id == NULL)
460 		return true;
461 	return strcmp(clp1->cl_owner_id, clp2->cl_owner_id) == 0;
462 }
463 
464 /**
465  * nfs40_walk_client_list - Find server that recognizes a client ID
466  *
467  * @new: nfs_client with client ID to test
468  * @result: OUT: found nfs_client, or new
469  * @cred: credential to use for trunking test
470  *
471  * Returns zero, a negative errno, or a negative NFS4ERR status.
472  * If zero is returned, an nfs_client pointer is planted in "result."
473  *
474  * NB: nfs40_walk_client_list() relies on the new nfs_client being
475  *     the last nfs_client on the list.
476  */
477 int nfs40_walk_client_list(struct nfs_client *new,
478 			   struct nfs_client **result,
479 			   struct rpc_cred *cred)
480 {
481 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
482 	struct nfs_client *pos, *prev = NULL;
483 	struct nfs4_setclientid_res clid = {
484 		.clientid	= new->cl_clientid,
485 		.confirm	= new->cl_confirm,
486 	};
487 	int status = -NFS4ERR_STALE_CLIENTID;
488 
489 	spin_lock(&nn->nfs_client_lock);
490 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
491 
492 		if (pos->rpc_ops != new->rpc_ops)
493 			continue;
494 
495 		if (pos->cl_minorversion != new->cl_minorversion)
496 			continue;
497 
498 		/* If "pos" isn't marked ready, we can't trust the
499 		 * remaining fields in "pos" */
500 		if (pos->cl_cons_state > NFS_CS_READY) {
501 			atomic_inc(&pos->cl_count);
502 			spin_unlock(&nn->nfs_client_lock);
503 
504 			nfs_put_client(prev);
505 			prev = pos;
506 
507 			status = nfs_wait_client_init_complete(pos);
508 			if (status < 0)
509 				goto out;
510 			status = -NFS4ERR_STALE_CLIENTID;
511 			spin_lock(&nn->nfs_client_lock);
512 		}
513 		if (pos->cl_cons_state != NFS_CS_READY)
514 			continue;
515 
516 		if (pos->cl_clientid != new->cl_clientid)
517 			continue;
518 
519 		if (!nfs4_match_client_owner_id(pos, new))
520 			continue;
521 
522 		atomic_inc(&pos->cl_count);
523 		spin_unlock(&nn->nfs_client_lock);
524 
525 		nfs_put_client(prev);
526 		prev = pos;
527 
528 		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
529 		switch (status) {
530 		case -NFS4ERR_STALE_CLIENTID:
531 			break;
532 		case 0:
533 			nfs4_swap_callback_idents(pos, new);
534 
535 			prev = NULL;
536 			*result = pos;
537 			dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
538 				__func__, pos, atomic_read(&pos->cl_count));
539 			goto out;
540 		case -ERESTARTSYS:
541 		case -ETIMEDOUT:
542 			/* The callback path may have been inadvertently
543 			 * changed. Schedule recovery!
544 			 */
545 			nfs4_schedule_path_down_recovery(pos);
546 		default:
547 			goto out;
548 		}
549 
550 		spin_lock(&nn->nfs_client_lock);
551 	}
552 	spin_unlock(&nn->nfs_client_lock);
553 
554 	/* No match found. The server lost our clientid */
555 out:
556 	nfs_put_client(prev);
557 	dprintk("NFS: <-- %s status = %d\n", __func__, status);
558 	return status;
559 }
560 
561 #ifdef CONFIG_NFS_V4_1
562 /*
563  * Returns true if the client IDs match
564  */
565 static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
566 {
567 	if (a->cl_clientid != b->cl_clientid) {
568 		dprintk("NFS: --> %s client ID %llx does not match %llx\n",
569 			__func__, a->cl_clientid, b->cl_clientid);
570 		return false;
571 	}
572 	dprintk("NFS: --> %s client ID %llx matches %llx\n",
573 		__func__, a->cl_clientid, b->cl_clientid);
574 	return true;
575 }
576 
577 /*
578  * Returns true if the server major ids match
579  */
580 static bool
581 nfs4_check_clientid_trunking(struct nfs_client *a, struct nfs_client *b)
582 {
583 	struct nfs41_server_owner *o1 = a->cl_serverowner;
584 	struct nfs41_server_owner *o2 = b->cl_serverowner;
585 
586 	if (o1->major_id_sz != o2->major_id_sz)
587 		goto out_major_mismatch;
588 	if (memcmp(o1->major_id, o2->major_id, o1->major_id_sz) != 0)
589 		goto out_major_mismatch;
590 
591 	dprintk("NFS: --> %s server owners match\n", __func__);
592 	return true;
593 
594 out_major_mismatch:
595 	dprintk("NFS: --> %s server owner major IDs do not match\n",
596 		__func__);
597 	return false;
598 }
599 
600 /**
601  * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
602  *
603  * @new: nfs_client with client ID to test
604  * @result: OUT: found nfs_client, or new
605  * @cred: credential to use for trunking test
606  *
607  * Returns zero, a negative errno, or a negative NFS4ERR status.
608  * If zero is returned, an nfs_client pointer is planted in "result."
609  *
610  * NB: nfs41_walk_client_list() relies on the new nfs_client being
611  *     the last nfs_client on the list.
612  */
613 int nfs41_walk_client_list(struct nfs_client *new,
614 			   struct nfs_client **result,
615 			   struct rpc_cred *cred)
616 {
617 	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
618 	struct nfs_client *pos, *prev = NULL;
619 	int status = -NFS4ERR_STALE_CLIENTID;
620 
621 	spin_lock(&nn->nfs_client_lock);
622 	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
623 
624 		if (pos == new)
625 			goto found;
626 
627 		if (pos->rpc_ops != new->rpc_ops)
628 			continue;
629 
630 		if (pos->cl_minorversion != new->cl_minorversion)
631 			continue;
632 
633 		/* If "pos" isn't marked ready, we can't trust the
634 		 * remaining fields in "pos", especially the client
635 		 * ID and serverowner fields.  Wait for CREATE_SESSION
636 		 * to finish. */
637 		if (pos->cl_cons_state > NFS_CS_READY) {
638 			atomic_inc(&pos->cl_count);
639 			spin_unlock(&nn->nfs_client_lock);
640 
641 			nfs_put_client(prev);
642 			prev = pos;
643 
644 			status = nfs_wait_client_init_complete(pos);
645 			spin_lock(&nn->nfs_client_lock);
646 			if (status < 0)
647 				break;
648 			status = -NFS4ERR_STALE_CLIENTID;
649 		}
650 		if (pos->cl_cons_state != NFS_CS_READY)
651 			continue;
652 
653 		if (!nfs4_match_clientids(pos, new))
654 			continue;
655 
656 		/*
657 		 * Note that session trunking is just a special subcase of
658 		 * client id trunking. In either case, we want to fall back
659 		 * to using the existing nfs_client.
660 		 */
661 		if (!nfs4_check_clientid_trunking(pos, new))
662 			continue;
663 
664 		/* Unlike NFSv4.0, we know that NFSv4.1 always uses the
665 		 * uniform string, however someone might switch the
666 		 * uniquifier string on us.
667 		 */
668 		if (!nfs4_match_client_owner_id(pos, new))
669 			continue;
670 found:
671 		atomic_inc(&pos->cl_count);
672 		*result = pos;
673 		status = 0;
674 		dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
675 			__func__, pos, atomic_read(&pos->cl_count));
676 		break;
677 	}
678 
679 	spin_unlock(&nn->nfs_client_lock);
680 	dprintk("NFS: <-- %s status = %d\n", __func__, status);
681 	nfs_put_client(prev);
682 	return status;
683 }
684 #endif	/* CONFIG_NFS_V4_1 */
685 
686 static void nfs4_destroy_server(struct nfs_server *server)
687 {
688 	nfs_server_return_all_delegations(server);
689 	unset_pnfs_layoutdriver(server);
690 	nfs4_purge_state_owners(server);
691 }
692 
693 /*
694  * NFSv4.0 callback thread helper
695  *
696  * Find a client by callback identifier
697  */
698 struct nfs_client *
699 nfs4_find_client_ident(struct net *net, int cb_ident)
700 {
701 	struct nfs_client *clp;
702 	struct nfs_net *nn = net_generic(net, nfs_net_id);
703 
704 	spin_lock(&nn->nfs_client_lock);
705 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
706 	if (clp)
707 		atomic_inc(&clp->cl_count);
708 	spin_unlock(&nn->nfs_client_lock);
709 	return clp;
710 }
711 
712 #if defined(CONFIG_NFS_V4_1)
713 /* Common match routine for v4.0 and v4.1 callback services */
714 static bool nfs4_cb_match_client(const struct sockaddr *addr,
715 		struct nfs_client *clp, u32 minorversion)
716 {
717 	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
718 
719 	/* Don't match clients that failed to initialise */
720 	if (!(clp->cl_cons_state == NFS_CS_READY ||
721 	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
722 		return false;
723 
724 	smp_rmb();
725 
726 	/* Match the version and minorversion */
727 	if (clp->rpc_ops->version != 4 ||
728 	    clp->cl_minorversion != minorversion)
729 		return false;
730 
731 	/* Match only the IP address, not the port number */
732 	return rpc_cmp_addr(addr, clap);
733 }
734 
735 /*
736  * NFSv4.1 callback thread helper
737  * For CB_COMPOUND calls, find a client by IP address, protocol version,
738  * minorversion, and sessionID
739  *
740  * Returns NULL if no such client
741  */
742 struct nfs_client *
743 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
744 			   struct nfs4_sessionid *sid, u32 minorversion)
745 {
746 	struct nfs_client *clp;
747 	struct nfs_net *nn = net_generic(net, nfs_net_id);
748 
749 	spin_lock(&nn->nfs_client_lock);
750 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
751 		if (nfs4_cb_match_client(addr, clp, minorversion) == false)
752 			continue;
753 
754 		if (!nfs4_has_session(clp))
755 			continue;
756 
757 		/* Match sessionid*/
758 		if (memcmp(clp->cl_session->sess_id.data,
759 		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
760 			continue;
761 
762 		atomic_inc(&clp->cl_count);
763 		spin_unlock(&nn->nfs_client_lock);
764 		return clp;
765 	}
766 	spin_unlock(&nn->nfs_client_lock);
767 	return NULL;
768 }
769 
770 #else /* CONFIG_NFS_V4_1 */
771 
772 struct nfs_client *
773 nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
774 			   struct nfs4_sessionid *sid, u32 minorversion)
775 {
776 	return NULL;
777 }
778 #endif /* CONFIG_NFS_V4_1 */
779 
780 /*
781  * Set up an NFS4 client
782  */
783 static int nfs4_set_client(struct nfs_server *server,
784 		const char *hostname,
785 		const struct sockaddr *addr,
786 		const size_t addrlen,
787 		const char *ip_addr,
788 		rpc_authflavor_t authflavour,
789 		int proto, const struct rpc_timeout *timeparms,
790 		u32 minorversion, struct net *net)
791 {
792 	struct nfs_client_initdata cl_init = {
793 		.hostname = hostname,
794 		.addr = addr,
795 		.addrlen = addrlen,
796 		.ip_addr = ip_addr,
797 		.nfs_mod = &nfs_v4,
798 		.proto = proto,
799 		.minorversion = minorversion,
800 		.net = net,
801 		.timeparms = timeparms,
802 	};
803 	struct nfs_client *clp;
804 	int error;
805 
806 	dprintk("--> nfs4_set_client()\n");
807 
808 	if (server->flags & NFS_MOUNT_NORESVPORT)
809 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
810 	if (server->options & NFS_OPTION_MIGRATION)
811 		set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
812 
813 	/* Allocate or find a client reference we can use */
814 	clp = nfs_get_client(&cl_init, authflavour);
815 	if (IS_ERR(clp)) {
816 		error = PTR_ERR(clp);
817 		goto error;
818 	}
819 
820 	if (server->nfs_client == clp) {
821 		error = -ELOOP;
822 		goto error;
823 	}
824 
825 	/*
826 	 * Query for the lease time on clientid setup or renewal
827 	 *
828 	 * Note that this will be set on nfs_clients that were created
829 	 * only for the DS role and did not set this bit, but now will
830 	 * serve a dual role.
831 	 */
832 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
833 
834 	server->nfs_client = clp;
835 	dprintk("<-- nfs4_set_client() = 0 [new %p]\n", clp);
836 	return 0;
837 error:
838 	dprintk("<-- nfs4_set_client() = xerror %d\n", error);
839 	return error;
840 }
841 
842 /*
843  * Set up a pNFS Data Server client.
844  *
845  * Return any existing nfs_client that matches server address,port,version
846  * and minorversion.
847  *
848  * For a new nfs_client, use a soft mount (default), a low retrans and a
849  * low timeout interval so that if a connection is lost, we retry through
850  * the MDS.
851  */
852 struct nfs_client *nfs4_set_ds_client(struct nfs_server *mds_srv,
853 		const struct sockaddr *ds_addr, int ds_addrlen,
854 		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans,
855 		u32 minor_version, rpc_authflavor_t au_flavor)
856 {
857 	struct rpc_timeout ds_timeout;
858 	struct nfs_client *mds_clp = mds_srv->nfs_client;
859 	struct nfs_client_initdata cl_init = {
860 		.addr = ds_addr,
861 		.addrlen = ds_addrlen,
862 		.nodename = mds_clp->cl_rpcclient->cl_nodename,
863 		.ip_addr = mds_clp->cl_ipaddr,
864 		.nfs_mod = &nfs_v4,
865 		.proto = ds_proto,
866 		.minorversion = minor_version,
867 		.net = mds_clp->cl_net,
868 		.timeparms = &ds_timeout,
869 	};
870 	struct nfs_client *clp;
871 	char buf[INET6_ADDRSTRLEN + 1];
872 
873 	if (rpc_ntop(ds_addr, buf, sizeof(buf)) <= 0)
874 		return ERR_PTR(-EINVAL);
875 	cl_init.hostname = buf;
876 
877 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
878 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
879 
880 	/*
881 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
882 	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
883 	 * (section 13.1 RFC 5661).
884 	 */
885 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
886 	clp = nfs_get_client(&cl_init, au_flavor);
887 
888 	dprintk("<-- %s %p\n", __func__, clp);
889 	return clp;
890 }
891 EXPORT_SYMBOL_GPL(nfs4_set_ds_client);
892 
893 /*
894  * Session has been established, and the client marked ready.
895  * Set the mount rsize and wsize with negotiated fore channel
896  * attributes which will be bound checked in nfs_server_set_fsinfo.
897  */
898 static void nfs4_session_set_rwsize(struct nfs_server *server)
899 {
900 #ifdef CONFIG_NFS_V4_1
901 	struct nfs4_session *sess;
902 	u32 server_resp_sz;
903 	u32 server_rqst_sz;
904 
905 	if (!nfs4_has_session(server->nfs_client))
906 		return;
907 	sess = server->nfs_client->cl_session;
908 	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
909 	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
910 
911 	if (server->rsize > server_resp_sz)
912 		server->rsize = server_resp_sz;
913 	if (server->wsize > server_rqst_sz)
914 		server->wsize = server_rqst_sz;
915 #endif /* CONFIG_NFS_V4_1 */
916 }
917 
918 static int nfs4_server_common_setup(struct nfs_server *server,
919 		struct nfs_fh *mntfh, bool auth_probe)
920 {
921 	struct nfs_fattr *fattr;
922 	int error;
923 
924 	/* data servers support only a subset of NFSv4.1 */
925 	if (is_ds_only_client(server->nfs_client))
926 		return -EPROTONOSUPPORT;
927 
928 	fattr = nfs_alloc_fattr();
929 	if (fattr == NULL)
930 		return -ENOMEM;
931 
932 	/* We must ensure the session is initialised first */
933 	error = nfs4_init_session(server->nfs_client);
934 	if (error < 0)
935 		goto out;
936 
937 	/* Set the basic capabilities */
938 	server->caps |= server->nfs_client->cl_mvops->init_caps;
939 	if (server->flags & NFS_MOUNT_NORDIRPLUS)
940 			server->caps &= ~NFS_CAP_READDIRPLUS;
941 	/*
942 	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
943 	 * authentication.
944 	 */
945 	if (nfs4_disable_idmapping &&
946 			server->client->cl_auth->au_flavor == RPC_AUTH_UNIX)
947 		server->caps |= NFS_CAP_UIDGID_NOMAP;
948 
949 
950 	/* Probe the root fh to retrieve its FSID and filehandle */
951 	error = nfs4_get_rootfh(server, mntfh, auth_probe);
952 	if (error < 0)
953 		goto out;
954 
955 	dprintk("Server FSID: %llx:%llx\n",
956 			(unsigned long long) server->fsid.major,
957 			(unsigned long long) server->fsid.minor);
958 	nfs_display_fhandle(mntfh, "Pseudo-fs root FH");
959 
960 	nfs4_session_set_rwsize(server);
961 
962 	error = nfs_probe_fsinfo(server, mntfh, fattr);
963 	if (error < 0)
964 		goto out;
965 
966 	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
967 		server->namelen = NFS4_MAXNAMLEN;
968 
969 	nfs_server_insert_lists(server);
970 	server->mount_time = jiffies;
971 	server->destroy = nfs4_destroy_server;
972 out:
973 	nfs_free_fattr(fattr);
974 	return error;
975 }
976 
977 /*
978  * Create a version 4 volume record
979  */
980 static int nfs4_init_server(struct nfs_server *server,
981 		struct nfs_parsed_mount_data *data)
982 {
983 	struct rpc_timeout timeparms;
984 	int error;
985 
986 	dprintk("--> nfs4_init_server()\n");
987 
988 	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
989 			data->timeo, data->retrans);
990 
991 	/* Initialise the client representation from the mount data */
992 	server->flags = data->flags;
993 	server->options = data->options;
994 	server->auth_info = data->auth_info;
995 
996 	/* Use the first specified auth flavor. If this flavor isn't
997 	 * allowed by the server, use the SECINFO path to try the
998 	 * other specified flavors */
999 	if (data->auth_info.flavor_len >= 1)
1000 		data->selected_flavor = data->auth_info.flavors[0];
1001 	else
1002 		data->selected_flavor = RPC_AUTH_UNIX;
1003 
1004 	/* Get a client record */
1005 	error = nfs4_set_client(server,
1006 			data->nfs_server.hostname,
1007 			(const struct sockaddr *)&data->nfs_server.address,
1008 			data->nfs_server.addrlen,
1009 			data->client_address,
1010 			data->selected_flavor,
1011 			data->nfs_server.protocol,
1012 			&timeparms,
1013 			data->minorversion,
1014 			data->net);
1015 	if (error < 0)
1016 		goto error;
1017 
1018 	if (data->rsize)
1019 		server->rsize = nfs_block_size(data->rsize, NULL);
1020 	if (data->wsize)
1021 		server->wsize = nfs_block_size(data->wsize, NULL);
1022 
1023 	server->acregmin = data->acregmin * HZ;
1024 	server->acregmax = data->acregmax * HZ;
1025 	server->acdirmin = data->acdirmin * HZ;
1026 	server->acdirmax = data->acdirmax * HZ;
1027 
1028 	server->port = data->nfs_server.port;
1029 
1030 	error = nfs_init_server_rpcclient(server, &timeparms,
1031 					  data->selected_flavor);
1032 
1033 error:
1034 	/* Done */
1035 	dprintk("<-- nfs4_init_server() = %d\n", error);
1036 	return error;
1037 }
1038 
1039 /*
1040  * Create a version 4 volume record
1041  * - keyed on server and FSID
1042  */
1043 /*struct nfs_server *nfs4_create_server(const struct nfs_parsed_mount_data *data,
1044 				      struct nfs_fh *mntfh)*/
1045 struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
1046 				      struct nfs_subversion *nfs_mod)
1047 {
1048 	struct nfs_server *server;
1049 	bool auth_probe;
1050 	int error;
1051 
1052 	dprintk("--> nfs4_create_server()\n");
1053 
1054 	server = nfs_alloc_server();
1055 	if (!server)
1056 		return ERR_PTR(-ENOMEM);
1057 
1058 	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
1059 
1060 	/* set up the general RPC client */
1061 	error = nfs4_init_server(server, mount_info->parsed);
1062 	if (error < 0)
1063 		goto error;
1064 
1065 	error = nfs4_server_common_setup(server, mount_info->mntfh, auth_probe);
1066 	if (error < 0)
1067 		goto error;
1068 
1069 	dprintk("<-- nfs4_create_server() = %p\n", server);
1070 	return server;
1071 
1072 error:
1073 	nfs_free_server(server);
1074 	dprintk("<-- nfs4_create_server() = error %d\n", error);
1075 	return ERR_PTR(error);
1076 }
1077 
1078 /*
1079  * Create an NFS4 referral server record
1080  */
1081 struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
1082 					       struct nfs_fh *mntfh)
1083 {
1084 	struct nfs_client *parent_client;
1085 	struct nfs_server *server, *parent_server;
1086 	bool auth_probe;
1087 	int error;
1088 
1089 	dprintk("--> nfs4_create_referral_server()\n");
1090 
1091 	server = nfs_alloc_server();
1092 	if (!server)
1093 		return ERR_PTR(-ENOMEM);
1094 
1095 	parent_server = NFS_SB(data->sb);
1096 	parent_client = parent_server->nfs_client;
1097 
1098 	/* Initialise the client representation from the parent server */
1099 	nfs_server_copy_userdata(server, parent_server);
1100 
1101 	/* Get a client representation.
1102 	 * Note: NFSv4 always uses TCP, */
1103 	error = nfs4_set_client(server, data->hostname,
1104 				data->addr,
1105 				data->addrlen,
1106 				parent_client->cl_ipaddr,
1107 				data->authflavor,
1108 				rpc_protocol(parent_server->client),
1109 				parent_server->client->cl_timeout,
1110 				parent_client->cl_mvops->minor_version,
1111 				parent_client->cl_net);
1112 	if (error < 0)
1113 		goto error;
1114 
1115 	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout, data->authflavor);
1116 	if (error < 0)
1117 		goto error;
1118 
1119 	auth_probe = parent_server->auth_info.flavor_len < 1;
1120 
1121 	error = nfs4_server_common_setup(server, mntfh, auth_probe);
1122 	if (error < 0)
1123 		goto error;
1124 
1125 	dprintk("<-- nfs_create_referral_server() = %p\n", server);
1126 	return server;
1127 
1128 error:
1129 	nfs_free_server(server);
1130 	dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
1131 	return ERR_PTR(error);
1132 }
1133 
1134 /*
1135  * Grab the destination's particulars, including lease expiry time.
1136  *
1137  * Returns zero if probe succeeded and retrieved FSID matches the FSID
1138  * we have cached.
1139  */
1140 static int nfs_probe_destination(struct nfs_server *server)
1141 {
1142 	struct inode *inode = d_inode(server->super->s_root);
1143 	struct nfs_fattr *fattr;
1144 	int error;
1145 
1146 	fattr = nfs_alloc_fattr();
1147 	if (fattr == NULL)
1148 		return -ENOMEM;
1149 
1150 	/* Sanity: the probe won't work if the destination server
1151 	 * does not recognize the migrated FH. */
1152 	error = nfs_probe_fsinfo(server, NFS_FH(inode), fattr);
1153 
1154 	nfs_free_fattr(fattr);
1155 	return error;
1156 }
1157 
1158 /**
1159  * nfs4_update_server - Move an nfs_server to a different nfs_client
1160  *
1161  * @server: represents FSID to be moved
1162  * @hostname: new end-point's hostname
1163  * @sap: new end-point's socket address
1164  * @salen: size of "sap"
1165  * @net: net namespace
1166  *
1167  * The nfs_server must be quiescent before this function is invoked.
1168  * Either its session is drained (NFSv4.1+), or its transport is
1169  * plugged and drained (NFSv4.0).
1170  *
1171  * Returns zero on success, or a negative errno value.
1172  */
1173 int nfs4_update_server(struct nfs_server *server, const char *hostname,
1174 		       struct sockaddr *sap, size_t salen, struct net *net)
1175 {
1176 	struct nfs_client *clp = server->nfs_client;
1177 	struct rpc_clnt *clnt = server->client;
1178 	struct xprt_create xargs = {
1179 		.ident		= clp->cl_proto,
1180 		.net		= net,
1181 		.dstaddr	= sap,
1182 		.addrlen	= salen,
1183 		.servername	= hostname,
1184 	};
1185 	char buf[INET6_ADDRSTRLEN + 1];
1186 	struct sockaddr_storage address;
1187 	struct sockaddr *localaddr = (struct sockaddr *)&address;
1188 	int error;
1189 
1190 	dprintk("--> %s: move FSID %llx:%llx to \"%s\")\n", __func__,
1191 			(unsigned long long)server->fsid.major,
1192 			(unsigned long long)server->fsid.minor,
1193 			hostname);
1194 
1195 	error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
1196 	if (error != 0) {
1197 		dprintk("<-- %s(): rpc_switch_client_transport returned %d\n",
1198 			__func__, error);
1199 		goto out;
1200 	}
1201 
1202 	error = rpc_localaddr(clnt, localaddr, sizeof(address));
1203 	if (error != 0) {
1204 		dprintk("<-- %s(): rpc_localaddr returned %d\n",
1205 			__func__, error);
1206 		goto out;
1207 	}
1208 
1209 	error = -EAFNOSUPPORT;
1210 	if (rpc_ntop(localaddr, buf, sizeof(buf)) == 0) {
1211 		dprintk("<-- %s(): rpc_ntop returned %d\n",
1212 			__func__, error);
1213 		goto out;
1214 	}
1215 
1216 	nfs_server_remove_lists(server);
1217 	error = nfs4_set_client(server, hostname, sap, salen, buf,
1218 				clp->cl_rpcclient->cl_auth->au_flavor,
1219 				clp->cl_proto, clnt->cl_timeout,
1220 				clp->cl_minorversion, net);
1221 	nfs_put_client(clp);
1222 	if (error != 0) {
1223 		nfs_server_insert_lists(server);
1224 		dprintk("<-- %s(): nfs4_set_client returned %d\n",
1225 			__func__, error);
1226 		goto out;
1227 	}
1228 
1229 	if (server->nfs_client->cl_hostname == NULL)
1230 		server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
1231 	nfs_server_insert_lists(server);
1232 
1233 	error = nfs_probe_destination(server);
1234 	if (error < 0)
1235 		goto out;
1236 
1237 	dprintk("<-- %s() succeeded\n", __func__);
1238 
1239 out:
1240 	return error;
1241 }
1242