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 #include "nfs4trace.h"
24
25 static void nfs_free_delegation(struct nfs_delegation *delegation)
26 {
27 if (delegation->cred) {
28 put_rpccred(delegation->cred);
29 delegation->cred = NULL;
30 }
31 kfree_rcu(delegation, rcu);
32 }
33
34 /**
35 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
36 * @delegation: delegation to process
37 *
38 */
39 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
40 {
41 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
42 }
43
44 static bool
45 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
46 fmode_t flags)
47 {
48 if (delegation != NULL && (delegation->type & flags) == flags &&
49 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
50 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
51 return true;
52 return false;
53 }
54
55 static int
56 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
57 {
58 struct nfs_delegation *delegation;
59 int ret = 0;
60
61 flags &= FMODE_READ|FMODE_WRITE;
62 rcu_read_lock();
63 delegation = rcu_dereference(NFS_I(inode)->delegation);
64 if (nfs4_is_valid_delegation(delegation, flags)) {
65 if (mark)
66 nfs_mark_delegation_referenced(delegation);
67 ret = 1;
68 }
69 rcu_read_unlock();
70 return ret;
71 }
72 /**
73 * nfs_have_delegation - check if inode has a delegation, mark it
74 * NFS_DELEGATION_REFERENCED if there is one.
75 * @inode: inode to check
76 * @flags: delegation types to check for
77 *
78 * Returns one if inode has the indicated delegation, otherwise zero.
79 */
80 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
81 {
82 return nfs4_do_check_delegation(inode, flags, true);
83 }
84
85 /*
86 * nfs4_check_delegation - check if inode has a delegation, do not mark
87 * NFS_DELEGATION_REFERENCED if it has one.
88 */
89 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
90 {
91 return nfs4_do_check_delegation(inode, flags, false);
92 }
93
94 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
95 {
96 struct inode *inode = state->inode;
97 struct file_lock *fl;
98 struct file_lock_context *flctx = inode->i_flctx;
99 struct list_head *list;
100 int status = 0;
101
102 if (flctx == NULL)
103 goto out;
104
105 list = &flctx->flc_posix;
106 spin_lock(&flctx->flc_lock);
107 restart:
108 list_for_each_entry(fl, list, fl_list) {
109 if (nfs_file_open_context(fl->fl_file) != ctx)
110 continue;
111 spin_unlock(&flctx->flc_lock);
112 status = nfs4_lock_delegation_recall(fl, state, stateid);
113 if (status < 0)
114 goto out;
115 spin_lock(&flctx->flc_lock);
116 }
117 if (list == &flctx->flc_posix) {
118 list = &flctx->flc_flock;
119 goto restart;
120 }
121 spin_unlock(&flctx->flc_lock);
122 out:
123 return status;
124 }
125
126 static int nfs_delegation_claim_opens(struct inode *inode,
127 const nfs4_stateid *stateid, fmode_t type)
128 {
129 struct nfs_inode *nfsi = NFS_I(inode);
130 struct nfs_open_context *ctx;
131 struct nfs4_state_owner *sp;
132 struct nfs4_state *state;
133 unsigned int seq;
134 int err;
135
136 again:
137 spin_lock(&inode->i_lock);
138 list_for_each_entry(ctx, &nfsi->open_files, list) {
139 state = ctx->state;
140 if (state == NULL)
141 continue;
142 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
143 continue;
144 if (!nfs4_valid_open_stateid(state))
145 continue;
146 if (!nfs4_stateid_match(&state->stateid, stateid))
147 continue;
148 get_nfs_open_context(ctx);
149 spin_unlock(&inode->i_lock);
150 sp = state->owner;
151 /* Block nfs4_proc_unlck */
152 mutex_lock(&sp->so_delegreturn_mutex);
153 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
154 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
155 if (!err)
156 err = nfs_delegation_claim_locks(ctx, state, stateid);
157 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
158 err = -EAGAIN;
159 mutex_unlock(&sp->so_delegreturn_mutex);
160 put_nfs_open_context(ctx);
161 if (err != 0)
162 return err;
163 goto again;
164 }
165 spin_unlock(&inode->i_lock);
166 return 0;
167 }
168
169 /**
170 * nfs_inode_reclaim_delegation - process a delegation reclaim request
171 * @inode: inode to process
172 * @cred: credential to use for request
173 * @res: new delegation state from server
174 *
175 */
176 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
177 struct nfs_openres *res)
178 {
179 struct nfs_delegation *delegation;
180 struct rpc_cred *oldcred = NULL;
181
182 rcu_read_lock();
183 delegation = rcu_dereference(NFS_I(inode)->delegation);
184 if (delegation != NULL) {
185 spin_lock(&delegation->lock);
186 if (delegation->inode != NULL) {
187 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
188 delegation->type = res->delegation_type;
189 delegation->pagemod_limit = res->pagemod_limit;
190 oldcred = delegation->cred;
191 delegation->cred = get_rpccred(cred);
192 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
193 &delegation->flags);
194 spin_unlock(&delegation->lock);
195 rcu_read_unlock();
196 put_rpccred(oldcred);
197 trace_nfs4_reclaim_delegation(inode, res->delegation_type);
198 } else {
199 /* We appear to have raced with a delegation return. */
200 spin_unlock(&delegation->lock);
201 rcu_read_unlock();
202 nfs_inode_set_delegation(inode, cred, res);
203 }
204 } else {
205 rcu_read_unlock();
206 }
207 }
208
209 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
210 {
211 int res = 0;
212
213 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
214 res = nfs4_proc_delegreturn(inode,
215 delegation->cred,
216 &delegation->stateid,
217 issync);
218 nfs_free_delegation(delegation);
219 return res;
220 }
221
222 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
223 {
224 struct inode *inode = NULL;
225
226 spin_lock(&delegation->lock);
227 if (delegation->inode != NULL)
228 inode = igrab(delegation->inode);
229 spin_unlock(&delegation->lock);
230 return inode;
231 }
232
233 static struct nfs_delegation *
234 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
235 {
236 struct nfs_delegation *ret = NULL;
237 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
238
239 if (delegation == NULL)
240 goto out;
241 spin_lock(&delegation->lock);
242 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
243 ret = delegation;
244 spin_unlock(&delegation->lock);
245 out:
246 return ret;
247 }
248
249 static struct nfs_delegation *
250 nfs_start_delegation_return(struct nfs_inode *nfsi)
251 {
252 struct nfs_delegation *delegation;
253
254 rcu_read_lock();
255 delegation = nfs_start_delegation_return_locked(nfsi);
256 rcu_read_unlock();
257 return delegation;
258 }
259
260 static void
261 nfs_abort_delegation_return(struct nfs_delegation *delegation,
262 struct nfs_client *clp)
263 {
264
265 spin_lock(&delegation->lock);
266 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
267 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
268 spin_unlock(&delegation->lock);
269 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
270 }
271
272 static struct nfs_delegation *
273 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
274 struct nfs_delegation *delegation,
275 struct nfs_client *clp)
276 {
277 struct nfs_delegation *deleg_cur =
278 rcu_dereference_protected(nfsi->delegation,
279 lockdep_is_held(&clp->cl_lock));
280
281 if (deleg_cur == NULL || delegation != deleg_cur)
282 return NULL;
283
284 spin_lock(&delegation->lock);
285 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
286 list_del_rcu(&delegation->super_list);
287 delegation->inode = NULL;
288 rcu_assign_pointer(nfsi->delegation, NULL);
289 spin_unlock(&delegation->lock);
290 return delegation;
291 }
292
293 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
294 struct nfs_delegation *delegation,
295 struct nfs_server *server)
296 {
297 struct nfs_client *clp = server->nfs_client;
298
299 spin_lock(&clp->cl_lock);
300 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
301 spin_unlock(&clp->cl_lock);
302 return delegation;
303 }
304
305 static struct nfs_delegation *
306 nfs_inode_detach_delegation(struct inode *inode)
307 {
308 struct nfs_inode *nfsi = NFS_I(inode);
309 struct nfs_server *server = NFS_SERVER(inode);
310 struct nfs_delegation *delegation;
311
312 delegation = nfs_start_delegation_return(nfsi);
313 if (delegation == NULL)
314 return NULL;
315 return nfs_detach_delegation(nfsi, delegation, server);
316 }
317
318 static void
319 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
320 const struct nfs_delegation *update)
321 {
322 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
323 delegation->stateid.seqid = update->stateid.seqid;
324 smp_wmb();
325 delegation->type = update->type;
326 }
327 }
328
329 /**
330 * nfs_inode_set_delegation - set up a delegation on an inode
331 * @inode: inode to which delegation applies
332 * @cred: cred to use for subsequent delegation processing
333 * @res: new delegation state from server
334 *
335 * Returns zero on success, or a negative errno value.
336 */
337 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
338 {
339 struct nfs_server *server = NFS_SERVER(inode);
340 struct nfs_client *clp = server->nfs_client;
341 struct nfs_inode *nfsi = NFS_I(inode);
342 struct nfs_delegation *delegation, *old_delegation;
343 struct nfs_delegation *freeme = NULL;
344 int status = 0;
345
346 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
347 if (delegation == NULL)
348 return -ENOMEM;
349 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
350 delegation->type = res->delegation_type;
351 delegation->pagemod_limit = res->pagemod_limit;
352 delegation->change_attr = inode->i_version;
353 delegation->cred = get_rpccred(cred);
354 delegation->inode = inode;
355 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
356 spin_lock_init(&delegation->lock);
357
358 spin_lock(&clp->cl_lock);
359 old_delegation = rcu_dereference_protected(nfsi->delegation,
360 lockdep_is_held(&clp->cl_lock));
361 if (old_delegation != NULL) {
362 /* Is this an update of the existing delegation? */
363 if (nfs4_stateid_match_other(&old_delegation->stateid,
364 &delegation->stateid)) {
365 nfs_update_inplace_delegation(old_delegation,
366 delegation);
367 goto out;
368 }
369 /*
370 * Deal with broken servers that hand out two
371 * delegations for the same file.
372 * Allow for upgrades to a WRITE delegation, but
373 * nothing else.
374 */
375 dfprintk(FILE, "%s: server %s handed out "
376 "a duplicate delegation!\n",
377 __func__, clp->cl_hostname);
378 if (delegation->type == old_delegation->type ||
379 !(delegation->type & FMODE_WRITE)) {
380 freeme = delegation;
381 delegation = NULL;
382 goto out;
383 }
384 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
385 &old_delegation->flags))
386 goto out;
387 freeme = nfs_detach_delegation_locked(nfsi,
388 old_delegation, clp);
389 if (freeme == NULL)
390 goto out;
391 }
392 list_add_tail_rcu(&delegation->super_list, &server->delegations);
393 rcu_assign_pointer(nfsi->delegation, delegation);
394 delegation = NULL;
395
396 /* Ensure we revalidate the attributes and page cache! */
397 spin_lock(&inode->i_lock);
398 nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
399 spin_unlock(&inode->i_lock);
400 trace_nfs4_set_delegation(inode, res->delegation_type);
401
402 out:
403 spin_unlock(&clp->cl_lock);
404 if (delegation != NULL)
405 nfs_free_delegation(delegation);
406 if (freeme != NULL)
407 nfs_do_return_delegation(inode, freeme, 0);
408 return status;
409 }
410
411 /*
412 * Basic procedure for returning a delegation to the server
413 */
414 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
415 {
416 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
417 struct nfs_inode *nfsi = NFS_I(inode);
418 int err = 0;
419
420 if (delegation == NULL)
421 return 0;
422 do {
423 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
424 break;
425 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
426 delegation->type);
427 if (!issync || err != -EAGAIN)
428 break;
429 /*
430 * Guard against state recovery
431 */
432 err = nfs4_wait_clnt_recover(clp);
433 } while (err == 0);
434
435 if (err) {
436 nfs_abort_delegation_return(delegation, clp);
437 goto out;
438 }
439 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
440 goto out;
441
442 err = nfs_do_return_delegation(inode, delegation, issync);
443 out:
444 return err;
445 }
446
447 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
448 {
449 bool ret = false;
450
451 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
452 goto out;
453 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
454 ret = true;
455 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
456 struct inode *inode;
457
458 spin_lock(&delegation->lock);
459 inode = delegation->inode;
460 if (inode && list_empty(&NFS_I(inode)->open_files))
461 ret = true;
462 spin_unlock(&delegation->lock);
463 }
464 out:
465 return ret;
466 }
467
468 /**
469 * nfs_client_return_marked_delegations - return previously marked delegations
470 * @clp: nfs_client to process
471 *
472 * Note that this function is designed to be called by the state
473 * manager thread. For this reason, it cannot flush the dirty data,
474 * since that could deadlock in case of a state recovery error.
475 *
476 * Returns zero on success, or a negative errno value.
477 */
478 int nfs_client_return_marked_delegations(struct nfs_client *clp)
479 {
480 struct nfs_delegation *delegation;
481 struct nfs_server *server;
482 struct inode *inode;
483 int err = 0;
484
485 restart:
486 rcu_read_lock();
487 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
488 list_for_each_entry_rcu(delegation, &server->delegations,
489 super_list) {
490 if (!nfs_delegation_need_return(delegation))
491 continue;
492 if (!nfs_sb_active(server->super))
493 continue;
494 inode = nfs_delegation_grab_inode(delegation);
495 if (inode == NULL) {
496 rcu_read_unlock();
497 nfs_sb_deactive(server->super);
498 goto restart;
499 }
500 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
501 rcu_read_unlock();
502
503 err = nfs_end_delegation_return(inode, delegation, 0);
504 iput(inode);
505 nfs_sb_deactive(server->super);
506 if (!err)
507 goto restart;
508 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
509 return err;
510 }
511 }
512 rcu_read_unlock();
513 return 0;
514 }
515
516 /**
517 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
518 * @inode: inode to process
519 *
520 * Does not protect against delegation reclaims, therefore really only safe
521 * to be called from nfs4_clear_inode().
522 */
523 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
524 {
525 struct nfs_delegation *delegation;
526
527 delegation = nfs_inode_detach_delegation(inode);
528 if (delegation != NULL)
529 nfs_do_return_delegation(inode, delegation, 1);
530 }
531
532 /**
533 * nfs_inode_return_delegation - synchronously return a delegation
534 * @inode: inode to process
535 *
536 * This routine will always flush any dirty data to disk on the
537 * assumption that if we need to return the delegation, then
538 * we should stop caching.
539 *
540 * Returns zero on success, or a negative errno value.
541 */
542 int nfs4_inode_return_delegation(struct inode *inode)
543 {
544 struct nfs_inode *nfsi = NFS_I(inode);
545 struct nfs_delegation *delegation;
546 int err = 0;
547
548 nfs_wb_all(inode);
549 delegation = nfs_start_delegation_return(nfsi);
550 if (delegation != NULL)
551 err = nfs_end_delegation_return(inode, delegation, 1);
552 return err;
553 }
554
555 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
556 struct nfs_delegation *delegation)
557 {
558 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
559 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
560 }
561
562 static void nfs_mark_return_delegation(struct nfs_server *server,
563 struct nfs_delegation *delegation)
564 {
565 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
566 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
567 }
568
569 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
570 {
571 struct nfs_delegation *delegation;
572 bool ret = false;
573
574 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
575 nfs_mark_return_delegation(server, delegation);
576 ret = true;
577 }
578 return ret;
579 }
580
581 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
582 {
583 struct nfs_server *server;
584
585 rcu_read_lock();
586 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
587 nfs_server_mark_return_all_delegations(server);
588 rcu_read_unlock();
589 }
590
591 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
592 {
593 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
594 nfs4_schedule_state_manager(clp);
595 }
596
597 /**
598 * nfs_expire_all_delegations
599 * @clp: client to process
600 *
601 */
602 void nfs_expire_all_delegations(struct nfs_client *clp)
603 {
604 nfs_client_mark_return_all_delegations(clp);
605 nfs_delegation_run_state_manager(clp);
606 }
607
608 /**
609 * nfs_super_return_all_delegations - return delegations for one superblock
610 * @sb: sb to process
611 *
612 */
613 void nfs_server_return_all_delegations(struct nfs_server *server)
614 {
615 struct nfs_client *clp = server->nfs_client;
616 bool need_wait;
617
618 if (clp == NULL)
619 return;
620
621 rcu_read_lock();
622 need_wait = nfs_server_mark_return_all_delegations(server);
623 rcu_read_unlock();
624
625 if (need_wait) {
626 nfs4_schedule_state_manager(clp);
627 nfs4_wait_clnt_recover(clp);
628 }
629 }
630
631 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
632 fmode_t flags)
633 {
634 struct nfs_delegation *delegation;
635
636 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
637 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
638 continue;
639 if (delegation->type & flags)
640 nfs_mark_return_if_closed_delegation(server, delegation);
641 }
642 }
643
644 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
645 fmode_t flags)
646 {
647 struct nfs_server *server;
648
649 rcu_read_lock();
650 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
651 nfs_mark_return_unused_delegation_types(server, flags);
652 rcu_read_unlock();
653 }
654
655 static void nfs_revoke_delegation(struct inode *inode)
656 {
657 struct nfs_delegation *delegation;
658 rcu_read_lock();
659 delegation = rcu_dereference(NFS_I(inode)->delegation);
660 if (delegation != NULL) {
661 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
662 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
663 }
664 rcu_read_unlock();
665 }
666
667 void nfs_remove_bad_delegation(struct inode *inode)
668 {
669 struct nfs_delegation *delegation;
670
671 nfs_revoke_delegation(inode);
672 delegation = nfs_inode_detach_delegation(inode);
673 if (delegation) {
674 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
675 nfs_free_delegation(delegation);
676 }
677 }
678 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
679
680 /**
681 * nfs_expire_unused_delegation_types
682 * @clp: client to process
683 * @flags: delegation types to expire
684 *
685 */
686 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
687 {
688 nfs_client_mark_return_unused_delegation_types(clp, flags);
689 nfs_delegation_run_state_manager(clp);
690 }
691
692 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
693 {
694 struct nfs_delegation *delegation;
695
696 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
697 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
698 continue;
699 nfs_mark_return_if_closed_delegation(server, delegation);
700 }
701 }
702
703 /**
704 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
705 * @clp: nfs_client to process
706 *
707 */
708 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
709 {
710 struct nfs_server *server;
711
712 rcu_read_lock();
713 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
714 nfs_mark_return_unreferenced_delegations(server);
715 rcu_read_unlock();
716
717 nfs_delegation_run_state_manager(clp);
718 }
719
720 /**
721 * nfs_async_inode_return_delegation - asynchronously return a delegation
722 * @inode: inode to process
723 * @stateid: state ID information
724 *
725 * Returns zero on success, or a negative errno value.
726 */
727 int nfs_async_inode_return_delegation(struct inode *inode,
728 const nfs4_stateid *stateid)
729 {
730 struct nfs_server *server = NFS_SERVER(inode);
731 struct nfs_client *clp = server->nfs_client;
732 struct nfs_delegation *delegation;
733
734 rcu_read_lock();
735 delegation = rcu_dereference(NFS_I(inode)->delegation);
736 if (delegation == NULL)
737 goto out_enoent;
738 if (stateid != NULL &&
739 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
740 goto out_enoent;
741 nfs_mark_return_delegation(server, delegation);
742 rcu_read_unlock();
743
744 nfs_delegation_run_state_manager(clp);
745 return 0;
746 out_enoent:
747 rcu_read_unlock();
748 return -ENOENT;
749 }
750
751 static struct inode *
752 nfs_delegation_find_inode_server(struct nfs_server *server,
753 const struct nfs_fh *fhandle)
754 {
755 struct nfs_delegation *delegation;
756 struct inode *res = NULL;
757
758 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
759 spin_lock(&delegation->lock);
760 if (delegation->inode != NULL &&
761 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
762 res = igrab(delegation->inode);
763 }
764 spin_unlock(&delegation->lock);
765 if (res != NULL)
766 break;
767 }
768 return res;
769 }
770
771 /**
772 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
773 * @clp: client state handle
774 * @fhandle: filehandle from a delegation recall
775 *
776 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
777 * cannot be found.
778 */
779 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
780 const struct nfs_fh *fhandle)
781 {
782 struct nfs_server *server;
783 struct inode *res = NULL;
784
785 rcu_read_lock();
786 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
787 res = nfs_delegation_find_inode_server(server, fhandle);
788 if (res != NULL)
789 break;
790 }
791 rcu_read_unlock();
792 return res;
793 }
794
795 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
796 {
797 struct nfs_delegation *delegation;
798
799 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
800 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
801 }
802
803 /**
804 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
805 * @clp: nfs_client to process
806 *
807 */
808 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
809 {
810 struct nfs_server *server;
811
812 rcu_read_lock();
813 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
814 nfs_delegation_mark_reclaim_server(server);
815 rcu_read_unlock();
816 }
817
818 /**
819 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
820 * @clp: nfs_client to process
821 *
822 */
823 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
824 {
825 struct nfs_delegation *delegation;
826 struct nfs_server *server;
827 struct inode *inode;
828
829 restart:
830 rcu_read_lock();
831 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
832 list_for_each_entry_rcu(delegation, &server->delegations,
833 super_list) {
834 if (test_bit(NFS_DELEGATION_RETURNING,
835 &delegation->flags))
836 continue;
837 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
838 &delegation->flags) == 0)
839 continue;
840 if (!nfs_sb_active(server->super))
841 continue;
842 inode = nfs_delegation_grab_inode(delegation);
843 if (inode == NULL) {
844 rcu_read_unlock();
845 nfs_sb_deactive(server->super);
846 goto restart;
847 }
848 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
849 rcu_read_unlock();
850 if (delegation != NULL) {
851 delegation = nfs_detach_delegation(NFS_I(inode),
852 delegation, server);
853 if (delegation != NULL)
854 nfs_free_delegation(delegation);
855 }
856 iput(inode);
857 nfs_sb_deactive(server->super);
858 goto restart;
859 }
860 }
861 rcu_read_unlock();
862 }
863
864 /**
865 * nfs_delegations_present - check for existence of delegations
866 * @clp: client state handle
867 *
868 * Returns one if there are any nfs_delegation structures attached
869 * to this nfs_client.
870 */
871 int nfs_delegations_present(struct nfs_client *clp)
872 {
873 struct nfs_server *server;
874 int ret = 0;
875
876 rcu_read_lock();
877 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
878 if (!list_empty(&server->delegations)) {
879 ret = 1;
880 break;
881 }
882 rcu_read_unlock();
883 return ret;
884 }
885
886 /**
887 * nfs4_copy_delegation_stateid - Copy inode's state ID information
888 * @inode: inode to check
889 * @flags: delegation type requirement
890 * @dst: stateid data structure to fill in
891 * @cred: optional argument to retrieve credential
892 *
893 * Returns "true" and fills in "dst->data" * if inode had a delegation,
894 * otherwise "false" is returned.
895 */
896 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
897 nfs4_stateid *dst, struct rpc_cred **cred)
898 {
899 struct nfs_inode *nfsi = NFS_I(inode);
900 struct nfs_delegation *delegation;
901 bool ret;
902
903 flags &= FMODE_READ|FMODE_WRITE;
904 rcu_read_lock();
905 delegation = rcu_dereference(nfsi->delegation);
906 ret = nfs4_is_valid_delegation(delegation, flags);
907 if (ret) {
908 nfs4_stateid_copy(dst, &delegation->stateid);
909 nfs_mark_delegation_referenced(delegation);
910 if (cred)
911 *cred = get_rpccred(delegation->cred);
912 }
913 rcu_read_unlock();
914 return ret;
915 }
916
917 /**
918 * nfs4_delegation_flush_on_close - Check if we must flush file on close
919 * @inode: inode to check
920 *
921 * This function checks the number of outstanding writes to the file
922 * against the delegation 'space_limit' field to see if
923 * the spec requires us to flush the file on close.
924 */
925 bool nfs4_delegation_flush_on_close(const struct inode *inode)
926 {
927 struct nfs_inode *nfsi = NFS_I(inode);
928 struct nfs_delegation *delegation;
929 bool ret = true;
930
931 rcu_read_lock();
932 delegation = rcu_dereference(nfsi->delegation);
933 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
934 goto out;
935 if (nfsi->nrequests < delegation->pagemod_limit)
936 ret = false;
937 out:
938 rcu_read_unlock();
939 return ret;
940 }
941
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