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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#include <linux/iversion.h>
16
17#include <linux/nfs4.h>
18#include <linux/nfs_fs.h>
19#include <linux/nfs_xdr.h>
20
21#include "nfs4_fs.h"
22#include "nfs4session.h"
23#include "delegation.h"
24#include "internal.h"
25#include "nfs4trace.h"
26
27static void nfs_free_delegation(struct nfs_delegation *delegation)
28{
29 if (delegation->cred) {
30 put_rpccred(delegation->cred);
31 delegation->cred = NULL;
32 }
33 kfree_rcu(delegation, rcu);
34}
35
36/**
37 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
38 * @delegation: delegation to process
39 *
40 */
41void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
42{
43 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
44}
45
46static bool
47nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
48 fmode_t flags)
49{
50 if (delegation != NULL && (delegation->type & flags) == flags &&
51 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
52 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
53 return true;
54 return false;
55}
56
57static int
58nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
59{
60 struct nfs_delegation *delegation;
61 int ret = 0;
62
63 flags &= FMODE_READ|FMODE_WRITE;
64 rcu_read_lock();
65 delegation = rcu_dereference(NFS_I(inode)->delegation);
66 if (nfs4_is_valid_delegation(delegation, flags)) {
67 if (mark)
68 nfs_mark_delegation_referenced(delegation);
69 ret = 1;
70 }
71 rcu_read_unlock();
72 return ret;
73}
74/**
75 * nfs_have_delegation - check if inode has a delegation, mark it
76 * NFS_DELEGATION_REFERENCED if there is one.
77 * @inode: inode to check
78 * @flags: delegation types to check for
79 *
80 * Returns one if inode has the indicated delegation, otherwise zero.
81 */
82int nfs4_have_delegation(struct inode *inode, fmode_t flags)
83{
84 return nfs4_do_check_delegation(inode, flags, true);
85}
86
87/*
88 * nfs4_check_delegation - check if inode has a delegation, do not mark
89 * NFS_DELEGATION_REFERENCED if it has one.
90 */
91int nfs4_check_delegation(struct inode *inode, fmode_t flags)
92{
93 return nfs4_do_check_delegation(inode, flags, false);
94}
95
96static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
97{
98 struct inode *inode = state->inode;
99 struct file_lock *fl;
100 struct file_lock_context *flctx = inode->i_flctx;
101 struct list_head *list;
102 int status = 0;
103
104 if (flctx == NULL)
105 goto out;
106
107 list = &flctx->flc_posix;
108 spin_lock(&flctx->flc_lock);
109restart:
110 list_for_each_entry(fl, list, fl_list) {
111 if (nfs_file_open_context(fl->fl_file) != ctx)
112 continue;
113 spin_unlock(&flctx->flc_lock);
114 status = nfs4_lock_delegation_recall(fl, state, stateid);
115 if (status < 0)
116 goto out;
117 spin_lock(&flctx->flc_lock);
118 }
119 if (list == &flctx->flc_posix) {
120 list = &flctx->flc_flock;
121 goto restart;
122 }
123 spin_unlock(&flctx->flc_lock);
124out:
125 return status;
126}
127
128static int nfs_delegation_claim_opens(struct inode *inode,
129 const nfs4_stateid *stateid, fmode_t type)
130{
131 struct nfs_inode *nfsi = NFS_I(inode);
132 struct nfs_open_context *ctx;
133 struct nfs4_state_owner *sp;
134 struct nfs4_state *state;
135 unsigned int seq;
136 int err;
137
138again:
139 spin_lock(&inode->i_lock);
140 list_for_each_entry(ctx, &nfsi->open_files, list) {
141 state = ctx->state;
142 if (state == NULL)
143 continue;
144 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
145 continue;
146 if (!nfs4_valid_open_stateid(state))
147 continue;
148 if (!nfs4_stateid_match(&state->stateid, stateid))
149 continue;
150 get_nfs_open_context(ctx);
151 spin_unlock(&inode->i_lock);
152 sp = state->owner;
153 /* Block nfs4_proc_unlck */
154 mutex_lock(&sp->so_delegreturn_mutex);
155 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
156 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
157 if (!err)
158 err = nfs_delegation_claim_locks(ctx, state, stateid);
159 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
160 err = -EAGAIN;
161 mutex_unlock(&sp->so_delegreturn_mutex);
162 put_nfs_open_context(ctx);
163 if (err != 0)
164 return err;
165 goto again;
166 }
167 spin_unlock(&inode->i_lock);
168 return 0;
169}
170
171/**
172 * nfs_inode_reclaim_delegation - process a delegation reclaim request
173 * @inode: inode to process
174 * @cred: credential to use for request
175 * @type: delegation type
176 * @stateid: delegation stateid
177 * @pagemod_limit: write delegation "space_limit"
178 *
179 */
180void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
181 fmode_t type,
182 const nfs4_stateid *stateid,
183 unsigned long pagemod_limit)
184{
185 struct nfs_delegation *delegation;
186 struct rpc_cred *oldcred = NULL;
187
188 rcu_read_lock();
189 delegation = rcu_dereference(NFS_I(inode)->delegation);
190 if (delegation != NULL) {
191 spin_lock(&delegation->lock);
192 if (delegation->inode != NULL) {
193 nfs4_stateid_copy(&delegation->stateid, stateid);
194 delegation->type = type;
195 delegation->pagemod_limit = pagemod_limit;
196 oldcred = delegation->cred;
197 delegation->cred = get_rpccred(cred);
198 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
199 &delegation->flags);
200 spin_unlock(&delegation->lock);
201 rcu_read_unlock();
202 put_rpccred(oldcred);
203 trace_nfs4_reclaim_delegation(inode, type);
204 return;
205 }
206 /* We appear to have raced with a delegation return. */
207 spin_unlock(&delegation->lock);
208 }
209 rcu_read_unlock();
210 nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
211}
212
213static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
214{
215 int res = 0;
216
217 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
218 res = nfs4_proc_delegreturn(inode,
219 delegation->cred,
220 &delegation->stateid,
221 issync);
222 nfs_free_delegation(delegation);
223 return res;
224}
225
226static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
227{
228 struct inode *inode = NULL;
229
230 spin_lock(&delegation->lock);
231 if (delegation->inode != NULL)
232 inode = igrab(delegation->inode);
233 spin_unlock(&delegation->lock);
234 return inode;
235}
236
237static struct nfs_delegation *
238nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
239{
240 struct nfs_delegation *ret = NULL;
241 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
242
243 if (delegation == NULL)
244 goto out;
245 spin_lock(&delegation->lock);
246 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
247 ret = delegation;
248 spin_unlock(&delegation->lock);
249out:
250 return ret;
251}
252
253static struct nfs_delegation *
254nfs_start_delegation_return(struct nfs_inode *nfsi)
255{
256 struct nfs_delegation *delegation;
257
258 rcu_read_lock();
259 delegation = nfs_start_delegation_return_locked(nfsi);
260 rcu_read_unlock();
261 return delegation;
262}
263
264static void
265nfs_abort_delegation_return(struct nfs_delegation *delegation,
266 struct nfs_client *clp)
267{
268
269 spin_lock(&delegation->lock);
270 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
271 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
272 spin_unlock(&delegation->lock);
273 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
274}
275
276static struct nfs_delegation *
277nfs_detach_delegation_locked(struct nfs_inode *nfsi,
278 struct nfs_delegation *delegation,
279 struct nfs_client *clp)
280{
281 struct nfs_delegation *deleg_cur =
282 rcu_dereference_protected(nfsi->delegation,
283 lockdep_is_held(&clp->cl_lock));
284
285 if (deleg_cur == NULL || delegation != deleg_cur)
286 return NULL;
287
288 spin_lock(&delegation->lock);
289 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
290 list_del_rcu(&delegation->super_list);
291 delegation->inode = NULL;
292 rcu_assign_pointer(nfsi->delegation, NULL);
293 spin_unlock(&delegation->lock);
294 return delegation;
295}
296
297static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
298 struct nfs_delegation *delegation,
299 struct nfs_server *server)
300{
301 struct nfs_client *clp = server->nfs_client;
302
303 spin_lock(&clp->cl_lock);
304 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
305 spin_unlock(&clp->cl_lock);
306 return delegation;
307}
308
309static struct nfs_delegation *
310nfs_inode_detach_delegation(struct inode *inode)
311{
312 struct nfs_inode *nfsi = NFS_I(inode);
313 struct nfs_server *server = NFS_SERVER(inode);
314 struct nfs_delegation *delegation;
315
316 delegation = nfs_start_delegation_return(nfsi);
317 if (delegation == NULL)
318 return NULL;
319 return nfs_detach_delegation(nfsi, delegation, server);
320}
321
322static void
323nfs_update_inplace_delegation(struct nfs_delegation *delegation,
324 const struct nfs_delegation *update)
325{
326 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
327 delegation->stateid.seqid = update->stateid.seqid;
328 smp_wmb();
329 delegation->type = update->type;
330 }
331}
332
333/**
334 * nfs_inode_set_delegation - set up a delegation on an inode
335 * @inode: inode to which delegation applies
336 * @cred: cred to use for subsequent delegation processing
337 * @type: delegation type
338 * @stateid: delegation stateid
339 * @pagemod_limit: write delegation "space_limit"
340 *
341 * Returns zero on success, or a negative errno value.
342 */
343int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred,
344 fmode_t type,
345 const nfs4_stateid *stateid,
346 unsigned long pagemod_limit)
347{
348 struct nfs_server *server = NFS_SERVER(inode);
349 struct nfs_client *clp = server->nfs_client;
350 struct nfs_inode *nfsi = NFS_I(inode);
351 struct nfs_delegation *delegation, *old_delegation;
352 struct nfs_delegation *freeme = NULL;
353 int status = 0;
354
355 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
356 if (delegation == NULL)
357 return -ENOMEM;
358 nfs4_stateid_copy(&delegation->stateid, stateid);
359 delegation->type = type;
360 delegation->pagemod_limit = pagemod_limit;
361 delegation->change_attr = inode_peek_iversion_raw(inode);
362 delegation->cred = get_rpccred(cred);
363 delegation->inode = inode;
364 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
365 spin_lock_init(&delegation->lock);
366
367 spin_lock(&clp->cl_lock);
368 old_delegation = rcu_dereference_protected(nfsi->delegation,
369 lockdep_is_held(&clp->cl_lock));
370 if (old_delegation != NULL) {
371 /* Is this an update of the existing delegation? */
372 if (nfs4_stateid_match_other(&old_delegation->stateid,
373 &delegation->stateid)) {
374 nfs_update_inplace_delegation(old_delegation,
375 delegation);
376 goto out;
377 }
378 /*
379 * Deal with broken servers that hand out two
380 * delegations for the same file.
381 * Allow for upgrades to a WRITE delegation, but
382 * nothing else.
383 */
384 dfprintk(FILE, "%s: server %s handed out "
385 "a duplicate delegation!\n",
386 __func__, clp->cl_hostname);
387 if (delegation->type == old_delegation->type ||
388 !(delegation->type & FMODE_WRITE)) {
389 freeme = delegation;
390 delegation = NULL;
391 goto out;
392 }
393 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
394 &old_delegation->flags))
395 goto out;
396 freeme = nfs_detach_delegation_locked(nfsi,
397 old_delegation, clp);
398 if (freeme == NULL)
399 goto out;
400 }
401 list_add_tail_rcu(&delegation->super_list, &server->delegations);
402 rcu_assign_pointer(nfsi->delegation, delegation);
403 delegation = NULL;
404
405 trace_nfs4_set_delegation(inode, type);
406
407out:
408 spin_unlock(&clp->cl_lock);
409 if (delegation != NULL)
410 nfs_free_delegation(delegation);
411 if (freeme != NULL)
412 nfs_do_return_delegation(inode, freeme, 0);
413 return status;
414}
415
416/*
417 * Basic procedure for returning a delegation to the server
418 */
419static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
420{
421 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
422 struct nfs_inode *nfsi = NFS_I(inode);
423 int err = 0;
424
425 if (delegation == NULL)
426 return 0;
427 do {
428 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
429 break;
430 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
431 delegation->type);
432 if (!issync || err != -EAGAIN)
433 break;
434 /*
435 * Guard against state recovery
436 */
437 err = nfs4_wait_clnt_recover(clp);
438 } while (err == 0);
439
440 if (err) {
441 nfs_abort_delegation_return(delegation, clp);
442 goto out;
443 }
444 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
445 goto out;
446
447 err = nfs_do_return_delegation(inode, delegation, issync);
448out:
449 return err;
450}
451
452static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
453{
454 bool ret = false;
455
456 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
457 goto out;
458 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
459 ret = true;
460 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
461 struct inode *inode;
462
463 spin_lock(&delegation->lock);
464 inode = delegation->inode;
465 if (inode && list_empty(&NFS_I(inode)->open_files))
466 ret = true;
467 spin_unlock(&delegation->lock);
468 }
469out:
470 return ret;
471}
472
473/**
474 * nfs_client_return_marked_delegations - return previously marked delegations
475 * @clp: nfs_client to process
476 *
477 * Note that this function is designed to be called by the state
478 * manager thread. For this reason, it cannot flush the dirty data,
479 * since that could deadlock in case of a state recovery error.
480 *
481 * Returns zero on success, or a negative errno value.
482 */
483int nfs_client_return_marked_delegations(struct nfs_client *clp)
484{
485 struct nfs_delegation *delegation;
486 struct nfs_server *server;
487 struct inode *inode;
488 int err = 0;
489
490restart:
491 rcu_read_lock();
492 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
493 list_for_each_entry_rcu(delegation, &server->delegations,
494 super_list) {
495 if (!nfs_delegation_need_return(delegation))
496 continue;
497 if (!nfs_sb_active(server->super))
498 continue;
499 inode = nfs_delegation_grab_inode(delegation);
500 if (inode == NULL) {
501 rcu_read_unlock();
502 nfs_sb_deactive(server->super);
503 goto restart;
504 }
505 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
506 rcu_read_unlock();
507
508 err = nfs_end_delegation_return(inode, delegation, 0);
509 iput(inode);
510 nfs_sb_deactive(server->super);
511 if (!err)
512 goto restart;
513 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
514 return err;
515 }
516 }
517 rcu_read_unlock();
518 return 0;
519}
520
521/**
522 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
523 * @inode: inode to process
524 *
525 * Does not protect against delegation reclaims, therefore really only safe
526 * to be called from nfs4_clear_inode().
527 */
528void nfs_inode_return_delegation_noreclaim(struct inode *inode)
529{
530 struct nfs_delegation *delegation;
531
532 delegation = nfs_inode_detach_delegation(inode);
533 if (delegation != NULL)
534 nfs_do_return_delegation(inode, delegation, 1);
535}
536
537/**
538 * nfs_inode_return_delegation - synchronously return a delegation
539 * @inode: inode to process
540 *
541 * This routine will always flush any dirty data to disk on the
542 * assumption that if we need to return the delegation, then
543 * we should stop caching.
544 *
545 * Returns zero on success, or a negative errno value.
546 */
547int nfs4_inode_return_delegation(struct inode *inode)
548{
549 struct nfs_inode *nfsi = NFS_I(inode);
550 struct nfs_delegation *delegation;
551 int err = 0;
552
553 nfs_wb_all(inode);
554 delegation = nfs_start_delegation_return(nfsi);
555 if (delegation != NULL)
556 err = nfs_end_delegation_return(inode, delegation, 1);
557 return err;
558}
559
560/**
561 * nfs4_inode_make_writeable
562 * @inode: pointer to inode
563 *
564 * Make the inode writeable by returning the delegation if necessary
565 *
566 * Returns zero on success, or a negative errno value.
567 */
568int nfs4_inode_make_writeable(struct inode *inode)
569{
570 if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
571 !nfs4_check_delegation(inode, FMODE_WRITE))
572 return nfs4_inode_return_delegation(inode);
573 return 0;
574}
575
576static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
577 struct nfs_delegation *delegation)
578{
579 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
580 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
581}
582
583static void nfs_mark_return_delegation(struct nfs_server *server,
584 struct nfs_delegation *delegation)
585{
586 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
587 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
588}
589
590static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
591{
592 struct nfs_delegation *delegation;
593 bool ret = false;
594
595 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
596 nfs_mark_return_delegation(server, delegation);
597 ret = true;
598 }
599 return ret;
600}
601
602static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
603{
604 struct nfs_server *server;
605
606 rcu_read_lock();
607 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
608 nfs_server_mark_return_all_delegations(server);
609 rcu_read_unlock();
610}
611
612static void nfs_delegation_run_state_manager(struct nfs_client *clp)
613{
614 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
615 nfs4_schedule_state_manager(clp);
616}
617
618/**
619 * nfs_expire_all_delegations
620 * @clp: client to process
621 *
622 */
623void nfs_expire_all_delegations(struct nfs_client *clp)
624{
625 nfs_client_mark_return_all_delegations(clp);
626 nfs_delegation_run_state_manager(clp);
627}
628
629/**
630 * nfs_super_return_all_delegations - return delegations for one superblock
631 * @sb: sb to process
632 *
633 */
634void nfs_server_return_all_delegations(struct nfs_server *server)
635{
636 struct nfs_client *clp = server->nfs_client;
637 bool need_wait;
638
639 if (clp == NULL)
640 return;
641
642 rcu_read_lock();
643 need_wait = nfs_server_mark_return_all_delegations(server);
644 rcu_read_unlock();
645
646 if (need_wait) {
647 nfs4_schedule_state_manager(clp);
648 nfs4_wait_clnt_recover(clp);
649 }
650}
651
652static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
653 fmode_t flags)
654{
655 struct nfs_delegation *delegation;
656
657 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
658 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
659 continue;
660 if (delegation->type & flags)
661 nfs_mark_return_if_closed_delegation(server, delegation);
662 }
663}
664
665static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
666 fmode_t flags)
667{
668 struct nfs_server *server;
669
670 rcu_read_lock();
671 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
672 nfs_mark_return_unused_delegation_types(server, flags);
673 rcu_read_unlock();
674}
675
676static void nfs_mark_delegation_revoked(struct nfs_server *server,
677 struct nfs_delegation *delegation)
678{
679 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
680 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
681 nfs_mark_return_delegation(server, delegation);
682}
683
684static bool nfs_revoke_delegation(struct inode *inode,
685 const nfs4_stateid *stateid)
686{
687 struct nfs_delegation *delegation;
688 nfs4_stateid tmp;
689 bool ret = false;
690
691 rcu_read_lock();
692 delegation = rcu_dereference(NFS_I(inode)->delegation);
693 if (delegation == NULL)
694 goto out;
695 if (stateid == NULL) {
696 nfs4_stateid_copy(&tmp, &delegation->stateid);
697 stateid = &tmp;
698 } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
699 goto out;
700 nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
701 ret = true;
702out:
703 rcu_read_unlock();
704 if (ret)
705 nfs_inode_find_state_and_recover(inode, stateid);
706 return ret;
707}
708
709void nfs_remove_bad_delegation(struct inode *inode,
710 const nfs4_stateid *stateid)
711{
712 struct nfs_delegation *delegation;
713
714 if (!nfs_revoke_delegation(inode, stateid))
715 return;
716 delegation = nfs_inode_detach_delegation(inode);
717 if (delegation)
718 nfs_free_delegation(delegation);
719}
720EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
721
722/**
723 * nfs_expire_unused_delegation_types
724 * @clp: client to process
725 * @flags: delegation types to expire
726 *
727 */
728void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
729{
730 nfs_client_mark_return_unused_delegation_types(clp, flags);
731 nfs_delegation_run_state_manager(clp);
732}
733
734static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
735{
736 struct nfs_delegation *delegation;
737
738 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
739 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
740 continue;
741 nfs_mark_return_if_closed_delegation(server, delegation);
742 }
743}
744
745/**
746 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
747 * @clp: nfs_client to process
748 *
749 */
750void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
751{
752 struct nfs_server *server;
753
754 rcu_read_lock();
755 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
756 nfs_mark_return_unreferenced_delegations(server);
757 rcu_read_unlock();
758
759 nfs_delegation_run_state_manager(clp);
760}
761
762/**
763 * nfs_async_inode_return_delegation - asynchronously return a delegation
764 * @inode: inode to process
765 * @stateid: state ID information
766 *
767 * Returns zero on success, or a negative errno value.
768 */
769int nfs_async_inode_return_delegation(struct inode *inode,
770 const nfs4_stateid *stateid)
771{
772 struct nfs_server *server = NFS_SERVER(inode);
773 struct nfs_client *clp = server->nfs_client;
774 struct nfs_delegation *delegation;
775
776 rcu_read_lock();
777 delegation = rcu_dereference(NFS_I(inode)->delegation);
778 if (delegation == NULL)
779 goto out_enoent;
780 if (stateid != NULL &&
781 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
782 goto out_enoent;
783 nfs_mark_return_delegation(server, delegation);
784 rcu_read_unlock();
785
786 nfs_delegation_run_state_manager(clp);
787 return 0;
788out_enoent:
789 rcu_read_unlock();
790 return -ENOENT;
791}
792
793static struct inode *
794nfs_delegation_find_inode_server(struct nfs_server *server,
795 const struct nfs_fh *fhandle)
796{
797 struct nfs_delegation *delegation;
798 struct inode *res = NULL;
799
800 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
801 spin_lock(&delegation->lock);
802 if (delegation->inode != NULL &&
803 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
804 res = igrab(delegation->inode);
805 }
806 spin_unlock(&delegation->lock);
807 if (res != NULL)
808 break;
809 }
810 return res;
811}
812
813/**
814 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
815 * @clp: client state handle
816 * @fhandle: filehandle from a delegation recall
817 *
818 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
819 * cannot be found.
820 */
821struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
822 const struct nfs_fh *fhandle)
823{
824 struct nfs_server *server;
825 struct inode *res = NULL;
826
827 rcu_read_lock();
828 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
829 res = nfs_delegation_find_inode_server(server, fhandle);
830 if (res != NULL)
831 break;
832 }
833 rcu_read_unlock();
834 return res;
835}
836
837static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
838{
839 struct nfs_delegation *delegation;
840
841 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
842 /*
843 * If the delegation may have been admin revoked, then we
844 * cannot reclaim it.
845 */
846 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
847 continue;
848 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
849 }
850}
851
852/**
853 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
854 * @clp: nfs_client to process
855 *
856 */
857void nfs_delegation_mark_reclaim(struct nfs_client *clp)
858{
859 struct nfs_server *server;
860
861 rcu_read_lock();
862 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
863 nfs_delegation_mark_reclaim_server(server);
864 rcu_read_unlock();
865}
866
867/**
868 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
869 * @clp: nfs_client to process
870 *
871 */
872void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
873{
874 struct nfs_delegation *delegation;
875 struct nfs_server *server;
876 struct inode *inode;
877
878restart:
879 rcu_read_lock();
880 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
881 list_for_each_entry_rcu(delegation, &server->delegations,
882 super_list) {
883 if (test_bit(NFS_DELEGATION_RETURNING,
884 &delegation->flags))
885 continue;
886 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
887 &delegation->flags) == 0)
888 continue;
889 if (!nfs_sb_active(server->super))
890 continue;
891 inode = nfs_delegation_grab_inode(delegation);
892 if (inode == NULL) {
893 rcu_read_unlock();
894 nfs_sb_deactive(server->super);
895 goto restart;
896 }
897 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
898 rcu_read_unlock();
899 if (delegation != NULL) {
900 delegation = nfs_detach_delegation(NFS_I(inode),
901 delegation, server);
902 if (delegation != NULL)
903 nfs_free_delegation(delegation);
904 }
905 iput(inode);
906 nfs_sb_deactive(server->super);
907 goto restart;
908 }
909 }
910 rcu_read_unlock();
911}
912
913static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
914{
915 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
916 BIT(NFS4CLNT_LEASE_EXPIRED) |
917 BIT(NFS4CLNT_SESSION_RESET))) != 0;
918}
919
920static void nfs_mark_test_expired_delegation(struct nfs_server *server,
921 struct nfs_delegation *delegation)
922{
923 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
924 return;
925 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
926 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
927 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
928}
929
930static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
931 struct inode *inode)
932{
933 struct nfs_delegation *delegation;
934
935 rcu_read_lock();
936 delegation = rcu_dereference(NFS_I(inode)->delegation);
937 if (delegation)
938 nfs_mark_test_expired_delegation(server, delegation);
939 rcu_read_unlock();
940
941}
942
943static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
944{
945 struct nfs_delegation *delegation;
946
947 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
948 nfs_mark_test_expired_delegation(server, delegation);
949}
950
951/**
952 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
953 * @clp: nfs_client to process
954 *
955 * Iterates through all the delegations associated with this server and
956 * marks them as needing to be checked for validity.
957 */
958void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
959{
960 struct nfs_server *server;
961
962 rcu_read_lock();
963 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
964 nfs_delegation_mark_test_expired_server(server);
965 rcu_read_unlock();
966}
967
968/**
969 * nfs_reap_expired_delegations - reap expired delegations
970 * @clp: nfs_client to process
971 *
972 * Iterates through all the delegations associated with this server and
973 * checks if they have may have been revoked. This function is usually
974 * expected to be called in cases where the server may have lost its
975 * lease.
976 */
977void nfs_reap_expired_delegations(struct nfs_client *clp)
978{
979 const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
980 struct nfs_delegation *delegation;
981 struct nfs_server *server;
982 struct inode *inode;
983 struct rpc_cred *cred;
984 nfs4_stateid stateid;
985
986restart:
987 rcu_read_lock();
988 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
989 list_for_each_entry_rcu(delegation, &server->delegations,
990 super_list) {
991 if (test_bit(NFS_DELEGATION_RETURNING,
992 &delegation->flags))
993 continue;
994 if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
995 &delegation->flags) == 0)
996 continue;
997 if (!nfs_sb_active(server->super))
998 continue;
999 inode = nfs_delegation_grab_inode(delegation);
1000 if (inode == NULL) {
1001 rcu_read_unlock();
1002 nfs_sb_deactive(server->super);
1003 goto restart;
1004 }
1005 cred = get_rpccred_rcu(delegation->cred);
1006 nfs4_stateid_copy(&stateid, &delegation->stateid);
1007 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1008 rcu_read_unlock();
1009 if (cred != NULL &&
1010 ops->test_and_free_expired(server, &stateid, cred) < 0) {
1011 nfs_revoke_delegation(inode, &stateid);
1012 nfs_inode_find_state_and_recover(inode, &stateid);
1013 }
1014 put_rpccred(cred);
1015 if (nfs4_server_rebooted(clp)) {
1016 nfs_inode_mark_test_expired_delegation(server,inode);
1017 iput(inode);
1018 nfs_sb_deactive(server->super);
1019 return;
1020 }
1021 iput(inode);
1022 nfs_sb_deactive(server->super);
1023 goto restart;
1024 }
1025 }
1026 rcu_read_unlock();
1027}
1028
1029void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1030 const nfs4_stateid *stateid)
1031{
1032 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1033 struct nfs_delegation *delegation;
1034 bool found = false;
1035
1036 rcu_read_lock();
1037 delegation = rcu_dereference(NFS_I(inode)->delegation);
1038 if (delegation &&
1039 nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1040 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1041 found = true;
1042 }
1043 rcu_read_unlock();
1044 if (found)
1045 nfs4_schedule_state_manager(clp);
1046}
1047
1048/**
1049 * nfs_delegations_present - check for existence of delegations
1050 * @clp: client state handle
1051 *
1052 * Returns one if there are any nfs_delegation structures attached
1053 * to this nfs_client.
1054 */
1055int nfs_delegations_present(struct nfs_client *clp)
1056{
1057 struct nfs_server *server;
1058 int ret = 0;
1059
1060 rcu_read_lock();
1061 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1062 if (!list_empty(&server->delegations)) {
1063 ret = 1;
1064 break;
1065 }
1066 rcu_read_unlock();
1067 return ret;
1068}
1069
1070/**
1071 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1072 * @dst: stateid to refresh
1073 * @inode: inode to check
1074 *
1075 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1076 * that matches our delegation stateid. Otherwise "false" is returned.
1077 */
1078bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1079{
1080 struct nfs_delegation *delegation;
1081 bool ret = false;
1082 if (!inode)
1083 goto out;
1084
1085 rcu_read_lock();
1086 delegation = rcu_dereference(NFS_I(inode)->delegation);
1087 if (delegation != NULL &&
1088 nfs4_stateid_match_other(dst, &delegation->stateid)) {
1089 dst->seqid = delegation->stateid.seqid;
1090 return ret;
1091 }
1092 rcu_read_unlock();
1093out:
1094 return ret;
1095}
1096
1097/**
1098 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1099 * @inode: inode to check
1100 * @flags: delegation type requirement
1101 * @dst: stateid data structure to fill in
1102 * @cred: optional argument to retrieve credential
1103 *
1104 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1105 * otherwise "false" is returned.
1106 */
1107bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1108 nfs4_stateid *dst, struct rpc_cred **cred)
1109{
1110 struct nfs_inode *nfsi = NFS_I(inode);
1111 struct nfs_delegation *delegation;
1112 bool ret;
1113
1114 flags &= FMODE_READ|FMODE_WRITE;
1115 rcu_read_lock();
1116 delegation = rcu_dereference(nfsi->delegation);
1117 ret = nfs4_is_valid_delegation(delegation, flags);
1118 if (ret) {
1119 nfs4_stateid_copy(dst, &delegation->stateid);
1120 nfs_mark_delegation_referenced(delegation);
1121 if (cred)
1122 *cred = get_rpccred(delegation->cred);
1123 }
1124 rcu_read_unlock();
1125 return ret;
1126}
1127
1128/**
1129 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1130 * @inode: inode to check
1131 *
1132 * This function checks the number of outstanding writes to the file
1133 * against the delegation 'space_limit' field to see if
1134 * the spec requires us to flush the file on close.
1135 */
1136bool nfs4_delegation_flush_on_close(const struct inode *inode)
1137{
1138 struct nfs_inode *nfsi = NFS_I(inode);
1139 struct nfs_delegation *delegation;
1140 bool ret = true;
1141
1142 rcu_read_lock();
1143 delegation = rcu_dereference(nfsi->delegation);
1144 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1145 goto out;
1146 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1147 ret = false;
1148out:
1149 rcu_read_unlock();
1150 return ret;
1151}
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
25static 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 */
39void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
40{
41 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
42}
43
44/**
45 * nfs_have_delegation - check if inode has a delegation
46 * @inode: inode to check
47 * @flags: delegation types to check for
48 *
49 * Returns one if inode has the indicated delegation, otherwise zero.
50 */
51int nfs4_have_delegation(struct inode *inode, fmode_t flags)
52{
53 struct nfs_delegation *delegation;
54 int ret = 0;
55
56 flags &= FMODE_READ|FMODE_WRITE;
57 rcu_read_lock();
58 delegation = rcu_dereference(NFS_I(inode)->delegation);
59 if (delegation != NULL && (delegation->type & flags) == flags &&
60 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
61 nfs_mark_delegation_referenced(delegation);
62 ret = 1;
63 }
64 rcu_read_unlock();
65 return ret;
66}
67
68static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
69{
70 struct inode *inode = state->inode;
71 struct file_lock *fl;
72 int status = 0;
73
74 if (inode->i_flock == NULL)
75 goto out;
76
77 /* Protect inode->i_flock using the i_lock */
78 spin_lock(&inode->i_lock);
79 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
80 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
81 continue;
82 if (nfs_file_open_context(fl->fl_file) != ctx)
83 continue;
84 spin_unlock(&inode->i_lock);
85 status = nfs4_lock_delegation_recall(fl, state, stateid);
86 if (status < 0)
87 goto out;
88 spin_lock(&inode->i_lock);
89 }
90 spin_unlock(&inode->i_lock);
91out:
92 return status;
93}
94
95static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
96{
97 struct nfs_inode *nfsi = NFS_I(inode);
98 struct nfs_open_context *ctx;
99 struct nfs4_state_owner *sp;
100 struct nfs4_state *state;
101 unsigned int seq;
102 int err;
103
104again:
105 spin_lock(&inode->i_lock);
106 list_for_each_entry(ctx, &nfsi->open_files, list) {
107 state = ctx->state;
108 if (state == NULL)
109 continue;
110 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
111 continue;
112 if (!nfs4_stateid_match(&state->stateid, stateid))
113 continue;
114 get_nfs_open_context(ctx);
115 spin_unlock(&inode->i_lock);
116 sp = state->owner;
117 /* Block nfs4_proc_unlck */
118 mutex_lock(&sp->so_delegreturn_mutex);
119 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
120 err = nfs4_open_delegation_recall(ctx, state, stateid);
121 if (!err)
122 err = nfs_delegation_claim_locks(ctx, state, stateid);
123 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
124 err = -EAGAIN;
125 mutex_unlock(&sp->so_delegreturn_mutex);
126 put_nfs_open_context(ctx);
127 if (err != 0)
128 return err;
129 goto again;
130 }
131 spin_unlock(&inode->i_lock);
132 return 0;
133}
134
135/**
136 * nfs_inode_reclaim_delegation - process a delegation reclaim request
137 * @inode: inode to process
138 * @cred: credential to use for request
139 * @res: new delegation state from server
140 *
141 */
142void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
143 struct nfs_openres *res)
144{
145 struct nfs_delegation *delegation;
146 struct rpc_cred *oldcred = NULL;
147
148 rcu_read_lock();
149 delegation = rcu_dereference(NFS_I(inode)->delegation);
150 if (delegation != NULL) {
151 spin_lock(&delegation->lock);
152 if (delegation->inode != NULL) {
153 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
154 delegation->type = res->delegation_type;
155 delegation->maxsize = res->maxsize;
156 oldcred = delegation->cred;
157 delegation->cred = get_rpccred(cred);
158 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
159 &delegation->flags);
160 NFS_I(inode)->delegation_state = delegation->type;
161 spin_unlock(&delegation->lock);
162 put_rpccred(oldcred);
163 rcu_read_unlock();
164 trace_nfs4_reclaim_delegation(inode, res->delegation_type);
165 } else {
166 /* We appear to have raced with a delegation return. */
167 spin_unlock(&delegation->lock);
168 rcu_read_unlock();
169 nfs_inode_set_delegation(inode, cred, res);
170 }
171 } else {
172 rcu_read_unlock();
173 }
174}
175
176static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
177{
178 int res = 0;
179
180 res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
181 nfs_free_delegation(delegation);
182 return res;
183}
184
185static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
186{
187 struct inode *inode = NULL;
188
189 spin_lock(&delegation->lock);
190 if (delegation->inode != NULL)
191 inode = igrab(delegation->inode);
192 spin_unlock(&delegation->lock);
193 return inode;
194}
195
196static struct nfs_delegation *
197nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
198{
199 struct nfs_delegation *ret = NULL;
200 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
201
202 if (delegation == NULL)
203 goto out;
204 spin_lock(&delegation->lock);
205 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
206 ret = delegation;
207 spin_unlock(&delegation->lock);
208out:
209 return ret;
210}
211
212static struct nfs_delegation *
213nfs_start_delegation_return(struct nfs_inode *nfsi)
214{
215 struct nfs_delegation *delegation;
216
217 rcu_read_lock();
218 delegation = nfs_start_delegation_return_locked(nfsi);
219 rcu_read_unlock();
220 return delegation;
221}
222
223static void
224nfs_abort_delegation_return(struct nfs_delegation *delegation,
225 struct nfs_client *clp)
226{
227
228 spin_lock(&delegation->lock);
229 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
230 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
231 spin_unlock(&delegation->lock);
232 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
233}
234
235static struct nfs_delegation *
236nfs_detach_delegation_locked(struct nfs_inode *nfsi,
237 struct nfs_delegation *delegation,
238 struct nfs_client *clp)
239{
240 struct nfs_delegation *deleg_cur =
241 rcu_dereference_protected(nfsi->delegation,
242 lockdep_is_held(&clp->cl_lock));
243
244 if (deleg_cur == NULL || delegation != deleg_cur)
245 return NULL;
246
247 spin_lock(&delegation->lock);
248 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
249 list_del_rcu(&delegation->super_list);
250 delegation->inode = NULL;
251 nfsi->delegation_state = 0;
252 rcu_assign_pointer(nfsi->delegation, NULL);
253 spin_unlock(&delegation->lock);
254 return delegation;
255}
256
257static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
258 struct nfs_delegation *delegation,
259 struct nfs_server *server)
260{
261 struct nfs_client *clp = server->nfs_client;
262
263 spin_lock(&clp->cl_lock);
264 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
265 spin_unlock(&clp->cl_lock);
266 return delegation;
267}
268
269static struct nfs_delegation *
270nfs_inode_detach_delegation(struct inode *inode)
271{
272 struct nfs_inode *nfsi = NFS_I(inode);
273 struct nfs_server *server = NFS_SERVER(inode);
274 struct nfs_delegation *delegation;
275
276 delegation = nfs_start_delegation_return(nfsi);
277 if (delegation == NULL)
278 return NULL;
279 return nfs_detach_delegation(nfsi, delegation, server);
280}
281
282/**
283 * nfs_inode_set_delegation - set up a delegation on an inode
284 * @inode: inode to which delegation applies
285 * @cred: cred to use for subsequent delegation processing
286 * @res: new delegation state from server
287 *
288 * Returns zero on success, or a negative errno value.
289 */
290int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
291{
292 struct nfs_server *server = NFS_SERVER(inode);
293 struct nfs_client *clp = server->nfs_client;
294 struct nfs_inode *nfsi = NFS_I(inode);
295 struct nfs_delegation *delegation, *old_delegation;
296 struct nfs_delegation *freeme = NULL;
297 int status = 0;
298
299 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
300 if (delegation == NULL)
301 return -ENOMEM;
302 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
303 delegation->type = res->delegation_type;
304 delegation->maxsize = res->maxsize;
305 delegation->change_attr = inode->i_version;
306 delegation->cred = get_rpccred(cred);
307 delegation->inode = inode;
308 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
309 spin_lock_init(&delegation->lock);
310
311 spin_lock(&clp->cl_lock);
312 old_delegation = rcu_dereference_protected(nfsi->delegation,
313 lockdep_is_held(&clp->cl_lock));
314 if (old_delegation != NULL) {
315 if (nfs4_stateid_match(&delegation->stateid,
316 &old_delegation->stateid) &&
317 delegation->type == old_delegation->type) {
318 goto out;
319 }
320 /*
321 * Deal with broken servers that hand out two
322 * delegations for the same file.
323 * Allow for upgrades to a WRITE delegation, but
324 * nothing else.
325 */
326 dfprintk(FILE, "%s: server %s handed out "
327 "a duplicate delegation!\n",
328 __func__, clp->cl_hostname);
329 if (delegation->type == old_delegation->type ||
330 !(delegation->type & FMODE_WRITE)) {
331 freeme = delegation;
332 delegation = NULL;
333 goto out;
334 }
335 freeme = nfs_detach_delegation_locked(nfsi,
336 old_delegation, clp);
337 if (freeme == NULL)
338 goto out;
339 }
340 list_add_rcu(&delegation->super_list, &server->delegations);
341 nfsi->delegation_state = delegation->type;
342 rcu_assign_pointer(nfsi->delegation, delegation);
343 delegation = NULL;
344
345 /* Ensure we revalidate the attributes and page cache! */
346 spin_lock(&inode->i_lock);
347 nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
348 spin_unlock(&inode->i_lock);
349 trace_nfs4_set_delegation(inode, res->delegation_type);
350
351out:
352 spin_unlock(&clp->cl_lock);
353 if (delegation != NULL)
354 nfs_free_delegation(delegation);
355 if (freeme != NULL)
356 nfs_do_return_delegation(inode, freeme, 0);
357 return status;
358}
359
360/*
361 * Basic procedure for returning a delegation to the server
362 */
363static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
364{
365 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
366 struct nfs_inode *nfsi = NFS_I(inode);
367 int err;
368
369 if (delegation == NULL)
370 return 0;
371 do {
372 err = nfs_delegation_claim_opens(inode, &delegation->stateid);
373 if (!issync || err != -EAGAIN)
374 break;
375 /*
376 * Guard against state recovery
377 */
378 err = nfs4_wait_clnt_recover(clp);
379 } while (err == 0);
380
381 if (err) {
382 nfs_abort_delegation_return(delegation, clp);
383 goto out;
384 }
385 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
386 goto out;
387
388 err = nfs_do_return_delegation(inode, delegation, issync);
389out:
390 return err;
391}
392
393static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
394{
395 bool ret = false;
396
397 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
398 ret = true;
399 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
400 struct inode *inode;
401
402 spin_lock(&delegation->lock);
403 inode = delegation->inode;
404 if (inode && list_empty(&NFS_I(inode)->open_files))
405 ret = true;
406 spin_unlock(&delegation->lock);
407 }
408 return ret;
409}
410
411/**
412 * nfs_client_return_marked_delegations - return previously marked delegations
413 * @clp: nfs_client to process
414 *
415 * Note that this function is designed to be called by the state
416 * manager thread. For this reason, it cannot flush the dirty data,
417 * since that could deadlock in case of a state recovery error.
418 *
419 * Returns zero on success, or a negative errno value.
420 */
421int nfs_client_return_marked_delegations(struct nfs_client *clp)
422{
423 struct nfs_delegation *delegation;
424 struct nfs_server *server;
425 struct inode *inode;
426 int err = 0;
427
428restart:
429 rcu_read_lock();
430 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
431 list_for_each_entry_rcu(delegation, &server->delegations,
432 super_list) {
433 if (!nfs_delegation_need_return(delegation))
434 continue;
435 inode = nfs_delegation_grab_inode(delegation);
436 if (inode == NULL)
437 continue;
438 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
439 rcu_read_unlock();
440
441 err = nfs_end_delegation_return(inode, delegation, 0);
442 iput(inode);
443 if (!err)
444 goto restart;
445 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
446 return err;
447 }
448 }
449 rcu_read_unlock();
450 return 0;
451}
452
453/**
454 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
455 * @inode: inode to process
456 *
457 * Does not protect against delegation reclaims, therefore really only safe
458 * to be called from nfs4_clear_inode().
459 */
460void nfs_inode_return_delegation_noreclaim(struct inode *inode)
461{
462 struct nfs_delegation *delegation;
463
464 delegation = nfs_inode_detach_delegation(inode);
465 if (delegation != NULL)
466 nfs_do_return_delegation(inode, delegation, 0);
467}
468
469/**
470 * nfs_inode_return_delegation - synchronously return a delegation
471 * @inode: inode to process
472 *
473 * This routine will always flush any dirty data to disk on the
474 * assumption that if we need to return the delegation, then
475 * we should stop caching.
476 *
477 * Returns zero on success, or a negative errno value.
478 */
479int nfs4_inode_return_delegation(struct inode *inode)
480{
481 struct nfs_inode *nfsi = NFS_I(inode);
482 struct nfs_delegation *delegation;
483 int err = 0;
484
485 nfs_wb_all(inode);
486 delegation = nfs_start_delegation_return(nfsi);
487 if (delegation != NULL)
488 err = nfs_end_delegation_return(inode, delegation, 1);
489 return err;
490}
491
492static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
493 struct nfs_delegation *delegation)
494{
495 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
496 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
497}
498
499static void nfs_mark_return_delegation(struct nfs_server *server,
500 struct nfs_delegation *delegation)
501{
502 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
503 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
504}
505
506static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
507{
508 struct nfs_delegation *delegation;
509 bool ret = false;
510
511 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
512 nfs_mark_return_delegation(server, delegation);
513 ret = true;
514 }
515 return ret;
516}
517
518static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
519{
520 struct nfs_server *server;
521
522 rcu_read_lock();
523 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
524 nfs_server_mark_return_all_delegations(server);
525 rcu_read_unlock();
526}
527
528static void nfs_delegation_run_state_manager(struct nfs_client *clp)
529{
530 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
531 nfs4_schedule_state_manager(clp);
532}
533
534/**
535 * nfs_expire_all_delegations
536 * @clp: client to process
537 *
538 */
539void nfs_expire_all_delegations(struct nfs_client *clp)
540{
541 nfs_client_mark_return_all_delegations(clp);
542 nfs_delegation_run_state_manager(clp);
543}
544
545/**
546 * nfs_super_return_all_delegations - return delegations for one superblock
547 * @sb: sb to process
548 *
549 */
550void nfs_server_return_all_delegations(struct nfs_server *server)
551{
552 struct nfs_client *clp = server->nfs_client;
553 bool need_wait;
554
555 if (clp == NULL)
556 return;
557
558 rcu_read_lock();
559 need_wait = nfs_server_mark_return_all_delegations(server);
560 rcu_read_unlock();
561
562 if (need_wait) {
563 nfs4_schedule_state_manager(clp);
564 nfs4_wait_clnt_recover(clp);
565 }
566}
567
568static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
569 fmode_t flags)
570{
571 struct nfs_delegation *delegation;
572
573 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
574 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
575 continue;
576 if (delegation->type & flags)
577 nfs_mark_return_if_closed_delegation(server, delegation);
578 }
579}
580
581static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
582 fmode_t flags)
583{
584 struct nfs_server *server;
585
586 rcu_read_lock();
587 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
588 nfs_mark_return_unused_delegation_types(server, flags);
589 rcu_read_unlock();
590}
591
592void nfs_remove_bad_delegation(struct inode *inode)
593{
594 struct nfs_delegation *delegation;
595
596 delegation = nfs_inode_detach_delegation(inode);
597 if (delegation) {
598 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
599 nfs_free_delegation(delegation);
600 }
601}
602EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
603
604/**
605 * nfs_expire_unused_delegation_types
606 * @clp: client to process
607 * @flags: delegation types to expire
608 *
609 */
610void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
611{
612 nfs_client_mark_return_unused_delegation_types(clp, flags);
613 nfs_delegation_run_state_manager(clp);
614}
615
616static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
617{
618 struct nfs_delegation *delegation;
619
620 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
621 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
622 continue;
623 nfs_mark_return_if_closed_delegation(server, delegation);
624 }
625}
626
627/**
628 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
629 * @clp: nfs_client to process
630 *
631 */
632void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
633{
634 struct nfs_server *server;
635
636 rcu_read_lock();
637 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
638 nfs_mark_return_unreferenced_delegations(server);
639 rcu_read_unlock();
640
641 nfs_delegation_run_state_manager(clp);
642}
643
644/**
645 * nfs_async_inode_return_delegation - asynchronously return a delegation
646 * @inode: inode to process
647 * @stateid: state ID information
648 *
649 * Returns zero on success, or a negative errno value.
650 */
651int nfs_async_inode_return_delegation(struct inode *inode,
652 const nfs4_stateid *stateid)
653{
654 struct nfs_server *server = NFS_SERVER(inode);
655 struct nfs_client *clp = server->nfs_client;
656 struct nfs_delegation *delegation;
657
658 filemap_flush(inode->i_mapping);
659
660 rcu_read_lock();
661 delegation = rcu_dereference(NFS_I(inode)->delegation);
662 if (delegation == NULL)
663 goto out_enoent;
664
665 if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
666 goto out_enoent;
667 nfs_mark_return_delegation(server, delegation);
668 rcu_read_unlock();
669
670 nfs_delegation_run_state_manager(clp);
671 return 0;
672out_enoent:
673 rcu_read_unlock();
674 return -ENOENT;
675}
676
677static struct inode *
678nfs_delegation_find_inode_server(struct nfs_server *server,
679 const struct nfs_fh *fhandle)
680{
681 struct nfs_delegation *delegation;
682 struct inode *res = NULL;
683
684 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
685 spin_lock(&delegation->lock);
686 if (delegation->inode != NULL &&
687 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
688 res = igrab(delegation->inode);
689 }
690 spin_unlock(&delegation->lock);
691 if (res != NULL)
692 break;
693 }
694 return res;
695}
696
697/**
698 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
699 * @clp: client state handle
700 * @fhandle: filehandle from a delegation recall
701 *
702 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
703 * cannot be found.
704 */
705struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
706 const struct nfs_fh *fhandle)
707{
708 struct nfs_server *server;
709 struct inode *res = NULL;
710
711 rcu_read_lock();
712 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
713 res = nfs_delegation_find_inode_server(server, fhandle);
714 if (res != NULL)
715 break;
716 }
717 rcu_read_unlock();
718 return res;
719}
720
721static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
722{
723 struct nfs_delegation *delegation;
724
725 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
726 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
727}
728
729/**
730 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
731 * @clp: nfs_client to process
732 *
733 */
734void nfs_delegation_mark_reclaim(struct nfs_client *clp)
735{
736 struct nfs_server *server;
737
738 rcu_read_lock();
739 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
740 nfs_delegation_mark_reclaim_server(server);
741 rcu_read_unlock();
742}
743
744/**
745 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
746 * @clp: nfs_client to process
747 *
748 */
749void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
750{
751 struct nfs_delegation *delegation;
752 struct nfs_server *server;
753 struct inode *inode;
754
755restart:
756 rcu_read_lock();
757 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
758 list_for_each_entry_rcu(delegation, &server->delegations,
759 super_list) {
760 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
761 &delegation->flags) == 0)
762 continue;
763 inode = nfs_delegation_grab_inode(delegation);
764 if (inode == NULL)
765 continue;
766 delegation = nfs_detach_delegation(NFS_I(inode),
767 delegation, server);
768 rcu_read_unlock();
769
770 if (delegation != NULL)
771 nfs_free_delegation(delegation);
772 iput(inode);
773 goto restart;
774 }
775 }
776 rcu_read_unlock();
777}
778
779/**
780 * nfs_delegations_present - check for existence of delegations
781 * @clp: client state handle
782 *
783 * Returns one if there are any nfs_delegation structures attached
784 * to this nfs_client.
785 */
786int nfs_delegations_present(struct nfs_client *clp)
787{
788 struct nfs_server *server;
789 int ret = 0;
790
791 rcu_read_lock();
792 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
793 if (!list_empty(&server->delegations)) {
794 ret = 1;
795 break;
796 }
797 rcu_read_unlock();
798 return ret;
799}
800
801/**
802 * nfs4_copy_delegation_stateid - Copy inode's state ID information
803 * @dst: stateid data structure to fill in
804 * @inode: inode to check
805 * @flags: delegation type requirement
806 *
807 * Returns "true" and fills in "dst->data" * if inode had a delegation,
808 * otherwise "false" is returned.
809 */
810bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
811 fmode_t flags)
812{
813 struct nfs_inode *nfsi = NFS_I(inode);
814 struct nfs_delegation *delegation;
815 bool ret;
816
817 flags &= FMODE_READ|FMODE_WRITE;
818 rcu_read_lock();
819 delegation = rcu_dereference(nfsi->delegation);
820 ret = (delegation != NULL && (delegation->type & flags) == flags);
821 if (ret) {
822 nfs4_stateid_copy(dst, &delegation->stateid);
823 nfs_mark_delegation_referenced(delegation);
824 }
825 rcu_read_unlock();
826 return ret;
827}