1 /*
2 * linux/fs/nfs/delegation.c
3 *
4 * Copyright (C) 2004 Trond Myklebust
5 *
6 * NFS file delegation management
7 *
8 */
9 #include <linux/completion.h>
10 #include <linux/kthread.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15
16 #include <linux/nfs4.h>
17 #include <linux/nfs_fs.h>
18 #include <linux/nfs_xdr.h>
19
20 #include "nfs4_fs.h"
21 #include "delegation.h"
22 #include "internal.h"
23
nfs_free_delegation(struct nfs_delegation * delegation)24 static void nfs_free_delegation(struct nfs_delegation *delegation)
25 {
26 if (delegation->cred) {
27 put_rpccred(delegation->cred);
28 delegation->cred = NULL;
29 }
30 kfree_rcu(delegation, rcu);
31 }
32
33 /**
34 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
35 * @delegation: delegation to process
36 *
37 */
nfs_mark_delegation_referenced(struct nfs_delegation * delegation)38 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
39 {
40 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
41 }
42
43 /**
44 * nfs_have_delegation - check if inode has a delegation
45 * @inode: inode to check
46 * @flags: delegation types to check for
47 *
48 * Returns one if inode has the indicated delegation, otherwise zero.
49 */
nfs_have_delegation(struct inode * inode,fmode_t flags)50 int nfs_have_delegation(struct inode *inode, fmode_t flags)
51 {
52 struct nfs_delegation *delegation;
53 int ret = 0;
54
55 flags &= FMODE_READ|FMODE_WRITE;
56 rcu_read_lock();
57 delegation = rcu_dereference(NFS_I(inode)->delegation);
58 if (delegation != NULL && (delegation->type & flags) == flags) {
59 nfs_mark_delegation_referenced(delegation);
60 ret = 1;
61 }
62 rcu_read_unlock();
63 return ret;
64 }
65
nfs_delegation_claim_locks(struct nfs_open_context * ctx,struct nfs4_state * state)66 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
67 {
68 struct inode *inode = state->inode;
69 struct file_lock *fl;
70 int status = 0;
71
72 if (inode->i_flock == NULL)
73 goto out;
74
75 /* Protect inode->i_flock using the file locks lock */
76 lock_flocks();
77 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
78 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
79 continue;
80 if (nfs_file_open_context(fl->fl_file) != ctx)
81 continue;
82 unlock_flocks();
83 status = nfs4_lock_delegation_recall(state, fl);
84 if (status < 0)
85 goto out;
86 lock_flocks();
87 }
88 unlock_flocks();
89 out:
90 return status;
91 }
92
nfs_delegation_claim_opens(struct inode * inode,const nfs4_stateid * stateid)93 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
94 {
95 struct nfs_inode *nfsi = NFS_I(inode);
96 struct nfs_open_context *ctx;
97 struct nfs4_state *state;
98 int err;
99
100 again:
101 spin_lock(&inode->i_lock);
102 list_for_each_entry(ctx, &nfsi->open_files, list) {
103 state = ctx->state;
104 if (state == NULL)
105 continue;
106 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
107 continue;
108 if (!nfs4_stateid_match(&state->stateid, stateid))
109 continue;
110 get_nfs_open_context(ctx);
111 spin_unlock(&inode->i_lock);
112 err = nfs4_open_delegation_recall(ctx, state, stateid);
113 if (err >= 0)
114 err = nfs_delegation_claim_locks(ctx, state);
115 put_nfs_open_context(ctx);
116 if (err != 0)
117 return err;
118 goto again;
119 }
120 spin_unlock(&inode->i_lock);
121 return 0;
122 }
123
124 /**
125 * nfs_inode_reclaim_delegation - process a delegation reclaim request
126 * @inode: inode to process
127 * @cred: credential to use for request
128 * @res: new delegation state from server
129 *
130 */
nfs_inode_reclaim_delegation(struct inode * inode,struct rpc_cred * cred,struct nfs_openres * res)131 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
132 struct nfs_openres *res)
133 {
134 struct nfs_delegation *delegation;
135 struct rpc_cred *oldcred = NULL;
136
137 rcu_read_lock();
138 delegation = rcu_dereference(NFS_I(inode)->delegation);
139 if (delegation != NULL) {
140 spin_lock(&delegation->lock);
141 if (delegation->inode != NULL) {
142 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
143 delegation->type = res->delegation_type;
144 delegation->maxsize = res->maxsize;
145 oldcred = delegation->cred;
146 delegation->cred = get_rpccred(cred);
147 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
148 &delegation->flags);
149 NFS_I(inode)->delegation_state = delegation->type;
150 spin_unlock(&delegation->lock);
151 put_rpccred(oldcred);
152 rcu_read_unlock();
153 } else {
154 /* We appear to have raced with a delegation return. */
155 spin_unlock(&delegation->lock);
156 rcu_read_unlock();
157 nfs_inode_set_delegation(inode, cred, res);
158 }
159 } else {
160 rcu_read_unlock();
161 }
162 }
163
nfs_do_return_delegation(struct inode * inode,struct nfs_delegation * delegation,int issync)164 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
165 {
166 int res = 0;
167
168 res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
169 nfs_free_delegation(delegation);
170 return res;
171 }
172
nfs_delegation_grab_inode(struct nfs_delegation * delegation)173 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
174 {
175 struct inode *inode = NULL;
176
177 spin_lock(&delegation->lock);
178 if (delegation->inode != NULL)
179 inode = igrab(delegation->inode);
180 spin_unlock(&delegation->lock);
181 return inode;
182 }
183
184 static struct nfs_delegation *
nfs_detach_delegation_locked(struct nfs_inode * nfsi,struct nfs_server * server)185 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
186 struct nfs_server *server)
187 {
188 struct nfs_delegation *delegation =
189 rcu_dereference_protected(nfsi->delegation,
190 lockdep_is_held(&server->nfs_client->cl_lock));
191
192 if (delegation == NULL)
193 goto nomatch;
194
195 spin_lock(&delegation->lock);
196 list_del_rcu(&delegation->super_list);
197 delegation->inode = NULL;
198 nfsi->delegation_state = 0;
199 rcu_assign_pointer(nfsi->delegation, NULL);
200 spin_unlock(&delegation->lock);
201 return delegation;
202 nomatch:
203 return NULL;
204 }
205
nfs_detach_delegation(struct nfs_inode * nfsi,struct nfs_server * server)206 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
207 struct nfs_server *server)
208 {
209 struct nfs_client *clp = server->nfs_client;
210 struct nfs_delegation *delegation;
211
212 spin_lock(&clp->cl_lock);
213 delegation = nfs_detach_delegation_locked(nfsi, server);
214 spin_unlock(&clp->cl_lock);
215 return delegation;
216 }
217
218 /**
219 * nfs_inode_set_delegation - set up a delegation on an inode
220 * @inode: inode to which delegation applies
221 * @cred: cred to use for subsequent delegation processing
222 * @res: new delegation state from server
223 *
224 * Returns zero on success, or a negative errno value.
225 */
nfs_inode_set_delegation(struct inode * inode,struct rpc_cred * cred,struct nfs_openres * res)226 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
227 {
228 struct nfs_server *server = NFS_SERVER(inode);
229 struct nfs_client *clp = server->nfs_client;
230 struct nfs_inode *nfsi = NFS_I(inode);
231 struct nfs_delegation *delegation, *old_delegation;
232 struct nfs_delegation *freeme = NULL;
233 int status = 0;
234
235 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
236 if (delegation == NULL)
237 return -ENOMEM;
238 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
239 delegation->type = res->delegation_type;
240 delegation->maxsize = res->maxsize;
241 delegation->change_attr = inode->i_version;
242 delegation->cred = get_rpccred(cred);
243 delegation->inode = inode;
244 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
245 spin_lock_init(&delegation->lock);
246
247 spin_lock(&clp->cl_lock);
248 old_delegation = rcu_dereference_protected(nfsi->delegation,
249 lockdep_is_held(&clp->cl_lock));
250 if (old_delegation != NULL) {
251 if (nfs4_stateid_match(&delegation->stateid,
252 &old_delegation->stateid) &&
253 delegation->type == old_delegation->type) {
254 goto out;
255 }
256 /*
257 * Deal with broken servers that hand out two
258 * delegations for the same file.
259 * Allow for upgrades to a WRITE delegation, but
260 * nothing else.
261 */
262 dfprintk(FILE, "%s: server %s handed out "
263 "a duplicate delegation!\n",
264 __func__, clp->cl_hostname);
265 if (delegation->type == old_delegation->type ||
266 !(delegation->type & FMODE_WRITE)) {
267 freeme = delegation;
268 delegation = NULL;
269 goto out;
270 }
271 freeme = nfs_detach_delegation_locked(nfsi, server);
272 }
273 list_add_rcu(&delegation->super_list, &server->delegations);
274 nfsi->delegation_state = delegation->type;
275 rcu_assign_pointer(nfsi->delegation, delegation);
276 delegation = NULL;
277
278 /* Ensure we revalidate the attributes and page cache! */
279 spin_lock(&inode->i_lock);
280 nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
281 spin_unlock(&inode->i_lock);
282
283 out:
284 spin_unlock(&clp->cl_lock);
285 if (delegation != NULL)
286 nfs_free_delegation(delegation);
287 if (freeme != NULL)
288 nfs_do_return_delegation(inode, freeme, 0);
289 return status;
290 }
291
292 /*
293 * Basic procedure for returning a delegation to the server
294 */
__nfs_inode_return_delegation(struct inode * inode,struct nfs_delegation * delegation,int issync)295 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
296 {
297 struct nfs_inode *nfsi = NFS_I(inode);
298 int err;
299
300 /*
301 * Guard against new delegated open/lock/unlock calls and against
302 * state recovery
303 */
304 down_write(&nfsi->rwsem);
305 err = nfs_delegation_claim_opens(inode, &delegation->stateid);
306 up_write(&nfsi->rwsem);
307 if (err)
308 goto out;
309
310 err = nfs_do_return_delegation(inode, delegation, issync);
311 out:
312 return err;
313 }
314
315 /**
316 * nfs_client_return_marked_delegations - return previously marked delegations
317 * @clp: nfs_client to process
318 *
319 * Returns zero on success, or a negative errno value.
320 */
nfs_client_return_marked_delegations(struct nfs_client * clp)321 int nfs_client_return_marked_delegations(struct nfs_client *clp)
322 {
323 struct nfs_delegation *delegation;
324 struct nfs_server *server;
325 struct inode *inode;
326 int err = 0;
327
328 restart:
329 rcu_read_lock();
330 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
331 list_for_each_entry_rcu(delegation, &server->delegations,
332 super_list) {
333 if (!test_and_clear_bit(NFS_DELEGATION_RETURN,
334 &delegation->flags))
335 continue;
336 inode = nfs_delegation_grab_inode(delegation);
337 if (inode == NULL)
338 continue;
339 delegation = nfs_detach_delegation(NFS_I(inode),
340 server);
341 rcu_read_unlock();
342
343 if (delegation != NULL) {
344 filemap_flush(inode->i_mapping);
345 err = __nfs_inode_return_delegation(inode,
346 delegation, 0);
347 }
348 iput(inode);
349 if (!err)
350 goto restart;
351 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
352 return err;
353 }
354 }
355 rcu_read_unlock();
356 return 0;
357 }
358
359 /**
360 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
361 * @inode: inode to process
362 *
363 * Does not protect against delegation reclaims, therefore really only safe
364 * to be called from nfs4_clear_inode().
365 */
nfs_inode_return_delegation_noreclaim(struct inode * inode)366 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
367 {
368 struct nfs_server *server = NFS_SERVER(inode);
369 struct nfs_inode *nfsi = NFS_I(inode);
370 struct nfs_delegation *delegation;
371
372 if (rcu_access_pointer(nfsi->delegation) != NULL) {
373 delegation = nfs_detach_delegation(nfsi, server);
374 if (delegation != NULL)
375 nfs_do_return_delegation(inode, delegation, 0);
376 }
377 }
378
379 /**
380 * nfs_inode_return_delegation - synchronously return a delegation
381 * @inode: inode to process
382 *
383 * Returns zero on success, or a negative errno value.
384 */
nfs_inode_return_delegation(struct inode * inode)385 int nfs_inode_return_delegation(struct inode *inode)
386 {
387 struct nfs_server *server = NFS_SERVER(inode);
388 struct nfs_inode *nfsi = NFS_I(inode);
389 struct nfs_delegation *delegation;
390 int err = 0;
391
392 if (rcu_access_pointer(nfsi->delegation) != NULL) {
393 delegation = nfs_detach_delegation(nfsi, server);
394 if (delegation != NULL) {
395 nfs_wb_all(inode);
396 err = __nfs_inode_return_delegation(inode, delegation, 1);
397 }
398 }
399 return err;
400 }
401
nfs_mark_return_delegation(struct nfs_server * server,struct nfs_delegation * delegation)402 static void nfs_mark_return_delegation(struct nfs_server *server,
403 struct nfs_delegation *delegation)
404 {
405 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
406 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
407 }
408
409 /**
410 * nfs_super_return_all_delegations - return delegations for one superblock
411 * @sb: sb to process
412 *
413 */
nfs_super_return_all_delegations(struct super_block * sb)414 void nfs_super_return_all_delegations(struct super_block *sb)
415 {
416 struct nfs_server *server = NFS_SB(sb);
417 struct nfs_client *clp = server->nfs_client;
418 struct nfs_delegation *delegation;
419
420 if (clp == NULL)
421 return;
422
423 rcu_read_lock();
424 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
425 spin_lock(&delegation->lock);
426 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
427 spin_unlock(&delegation->lock);
428 }
429 rcu_read_unlock();
430
431 if (nfs_client_return_marked_delegations(clp) != 0)
432 nfs4_schedule_state_manager(clp);
433 }
434
nfs_mark_return_all_delegation_types(struct nfs_server * server,fmode_t flags)435 static void nfs_mark_return_all_delegation_types(struct nfs_server *server,
436 fmode_t flags)
437 {
438 struct nfs_delegation *delegation;
439
440 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
441 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
442 continue;
443 if (delegation->type & flags)
444 nfs_mark_return_delegation(server, delegation);
445 }
446 }
447
nfs_client_mark_return_all_delegation_types(struct nfs_client * clp,fmode_t flags)448 static void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp,
449 fmode_t flags)
450 {
451 struct nfs_server *server;
452
453 rcu_read_lock();
454 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
455 nfs_mark_return_all_delegation_types(server, flags);
456 rcu_read_unlock();
457 }
458
nfs_delegation_run_state_manager(struct nfs_client * clp)459 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
460 {
461 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
462 nfs4_schedule_state_manager(clp);
463 }
464
nfs_remove_bad_delegation(struct inode * inode)465 void nfs_remove_bad_delegation(struct inode *inode)
466 {
467 struct nfs_delegation *delegation;
468
469 delegation = nfs_detach_delegation(NFS_I(inode), NFS_SERVER(inode));
470 if (delegation) {
471 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
472 nfs_free_delegation(delegation);
473 }
474 }
475 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
476
477 /**
478 * nfs_expire_all_delegation_types
479 * @clp: client to process
480 * @flags: delegation types to expire
481 *
482 */
nfs_expire_all_delegation_types(struct nfs_client * clp,fmode_t flags)483 void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
484 {
485 nfs_client_mark_return_all_delegation_types(clp, flags);
486 nfs_delegation_run_state_manager(clp);
487 }
488
489 /**
490 * nfs_expire_all_delegations
491 * @clp: client to process
492 *
493 */
nfs_expire_all_delegations(struct nfs_client * clp)494 void nfs_expire_all_delegations(struct nfs_client *clp)
495 {
496 nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
497 }
498
nfs_mark_return_unreferenced_delegations(struct nfs_server * server)499 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
500 {
501 struct nfs_delegation *delegation;
502
503 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
504 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
505 continue;
506 nfs_mark_return_delegation(server, delegation);
507 }
508 }
509
510 /**
511 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
512 * @clp: nfs_client to process
513 *
514 */
nfs_expire_unreferenced_delegations(struct nfs_client * clp)515 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
516 {
517 struct nfs_server *server;
518
519 rcu_read_lock();
520 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
521 nfs_mark_return_unreferenced_delegations(server);
522 rcu_read_unlock();
523
524 nfs_delegation_run_state_manager(clp);
525 }
526
527 /**
528 * nfs_async_inode_return_delegation - asynchronously return a delegation
529 * @inode: inode to process
530 * @stateid: state ID information
531 *
532 * Returns zero on success, or a negative errno value.
533 */
nfs_async_inode_return_delegation(struct inode * inode,const nfs4_stateid * stateid)534 int nfs_async_inode_return_delegation(struct inode *inode,
535 const nfs4_stateid *stateid)
536 {
537 struct nfs_server *server = NFS_SERVER(inode);
538 struct nfs_client *clp = server->nfs_client;
539 struct nfs_delegation *delegation;
540
541 rcu_read_lock();
542 delegation = rcu_dereference(NFS_I(inode)->delegation);
543 if (delegation == NULL)
544 goto out_enoent;
545
546 if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
547 goto out_enoent;
548 nfs_mark_return_delegation(server, delegation);
549 rcu_read_unlock();
550
551 nfs_delegation_run_state_manager(clp);
552 return 0;
553 out_enoent:
554 rcu_read_unlock();
555 return -ENOENT;
556 }
557
558 static struct inode *
nfs_delegation_find_inode_server(struct nfs_server * server,const struct nfs_fh * fhandle)559 nfs_delegation_find_inode_server(struct nfs_server *server,
560 const struct nfs_fh *fhandle)
561 {
562 struct nfs_delegation *delegation;
563 struct inode *res = NULL;
564
565 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
566 spin_lock(&delegation->lock);
567 if (delegation->inode != NULL &&
568 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
569 res = igrab(delegation->inode);
570 }
571 spin_unlock(&delegation->lock);
572 if (res != NULL)
573 break;
574 }
575 return res;
576 }
577
578 /**
579 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
580 * @clp: client state handle
581 * @fhandle: filehandle from a delegation recall
582 *
583 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
584 * cannot be found.
585 */
nfs_delegation_find_inode(struct nfs_client * clp,const struct nfs_fh * fhandle)586 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
587 const struct nfs_fh *fhandle)
588 {
589 struct nfs_server *server;
590 struct inode *res = NULL;
591
592 rcu_read_lock();
593 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
594 res = nfs_delegation_find_inode_server(server, fhandle);
595 if (res != NULL)
596 break;
597 }
598 rcu_read_unlock();
599 return res;
600 }
601
nfs_delegation_mark_reclaim_server(struct nfs_server * server)602 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
603 {
604 struct nfs_delegation *delegation;
605
606 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
607 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
608 }
609
610 /**
611 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
612 * @clp: nfs_client to process
613 *
614 */
nfs_delegation_mark_reclaim(struct nfs_client * clp)615 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
616 {
617 struct nfs_server *server;
618
619 rcu_read_lock();
620 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
621 nfs_delegation_mark_reclaim_server(server);
622 rcu_read_unlock();
623 }
624
625 /**
626 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
627 * @clp: nfs_client to process
628 *
629 */
nfs_delegation_reap_unclaimed(struct nfs_client * clp)630 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
631 {
632 struct nfs_delegation *delegation;
633 struct nfs_server *server;
634 struct inode *inode;
635
636 restart:
637 rcu_read_lock();
638 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
639 list_for_each_entry_rcu(delegation, &server->delegations,
640 super_list) {
641 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
642 &delegation->flags) == 0)
643 continue;
644 inode = nfs_delegation_grab_inode(delegation);
645 if (inode == NULL)
646 continue;
647 delegation = nfs_detach_delegation(NFS_I(inode),
648 server);
649 rcu_read_unlock();
650
651 if (delegation != NULL)
652 nfs_free_delegation(delegation);
653 iput(inode);
654 goto restart;
655 }
656 }
657 rcu_read_unlock();
658 }
659
660 /**
661 * nfs_delegations_present - check for existence of delegations
662 * @clp: client state handle
663 *
664 * Returns one if there are any nfs_delegation structures attached
665 * to this nfs_client.
666 */
nfs_delegations_present(struct nfs_client * clp)667 int nfs_delegations_present(struct nfs_client *clp)
668 {
669 struct nfs_server *server;
670 int ret = 0;
671
672 rcu_read_lock();
673 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
674 if (!list_empty(&server->delegations)) {
675 ret = 1;
676 break;
677 }
678 rcu_read_unlock();
679 return ret;
680 }
681
682 /**
683 * nfs4_copy_delegation_stateid - Copy inode's state ID information
684 * @dst: stateid data structure to fill in
685 * @inode: inode to check
686 * @flags: delegation type requirement
687 *
688 * Returns "true" and fills in "dst->data" * if inode had a delegation,
689 * otherwise "false" is returned.
690 */
nfs4_copy_delegation_stateid(nfs4_stateid * dst,struct inode * inode,fmode_t flags)691 bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
692 fmode_t flags)
693 {
694 struct nfs_inode *nfsi = NFS_I(inode);
695 struct nfs_delegation *delegation;
696 bool ret;
697
698 flags &= FMODE_READ|FMODE_WRITE;
699 rcu_read_lock();
700 delegation = rcu_dereference(nfsi->delegation);
701 ret = (delegation != NULL && (delegation->type & flags) == flags);
702 if (ret) {
703 nfs4_stateid_copy(dst, &delegation->stateid);
704 nfs_mark_delegation_referenced(delegation);
705 }
706 rcu_read_unlock();
707 return ret;
708 }
709