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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/delegation.c
4 *
5 * Copyright (C) 2004 Trond Myklebust
6 *
7 * NFS file delegation management
8 *
9 */
10#include <linux/completion.h>
11#include <linux/kthread.h>
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/slab.h>
15#include <linux/spinlock.h>
16#include <linux/iversion.h>
17
18#include <linux/nfs4.h>
19#include <linux/nfs_fs.h>
20#include <linux/nfs_xdr.h>
21
22#include "nfs4_fs.h"
23#include "nfs4session.h"
24#include "delegation.h"
25#include "internal.h"
26#include "nfs4trace.h"
27
28#define NFS_DEFAULT_DELEGATION_WATERMARK (5000U)
29
30static atomic_long_t nfs_active_delegations;
31static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
32
33static void __nfs_free_delegation(struct nfs_delegation *delegation)
34{
35 put_cred(delegation->cred);
36 delegation->cred = NULL;
37 kfree_rcu(delegation, rcu);
38}
39
40static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation)
41{
42 if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
43 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
44 atomic_long_dec(&nfs_active_delegations);
45 if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
46 nfs_clear_verifier_delegated(delegation->inode);
47 }
48}
49
50static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
51{
52 refcount_inc(&delegation->refcount);
53 return delegation;
54}
55
56static void nfs_put_delegation(struct nfs_delegation *delegation)
57{
58 if (refcount_dec_and_test(&delegation->refcount))
59 __nfs_free_delegation(delegation);
60}
61
62static void nfs_free_delegation(struct nfs_delegation *delegation)
63{
64 nfs_mark_delegation_revoked(delegation);
65 nfs_put_delegation(delegation);
66}
67
68/**
69 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
70 * @delegation: delegation to process
71 *
72 */
73void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
74{
75 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
76}
77
78static bool
79nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
80 fmode_t flags)
81{
82 if (delegation != NULL && (delegation->type & flags) == flags &&
83 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
84 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
85 return true;
86 return false;
87}
88
89struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
90{
91 struct nfs_delegation *delegation;
92
93 delegation = rcu_dereference(NFS_I(inode)->delegation);
94 if (nfs4_is_valid_delegation(delegation, 0))
95 return delegation;
96 return NULL;
97}
98
99static int
100nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
101{
102 struct nfs_delegation *delegation;
103 int ret = 0;
104
105 flags &= FMODE_READ|FMODE_WRITE;
106 rcu_read_lock();
107 delegation = rcu_dereference(NFS_I(inode)->delegation);
108 if (nfs4_is_valid_delegation(delegation, flags)) {
109 if (mark)
110 nfs_mark_delegation_referenced(delegation);
111 ret = 1;
112 }
113 rcu_read_unlock();
114 return ret;
115}
116/**
117 * nfs_have_delegation - check if inode has a delegation, mark it
118 * NFS_DELEGATION_REFERENCED if there is one.
119 * @inode: inode to check
120 * @flags: delegation types to check for
121 *
122 * Returns one if inode has the indicated delegation, otherwise zero.
123 */
124int nfs4_have_delegation(struct inode *inode, fmode_t flags)
125{
126 return nfs4_do_check_delegation(inode, flags, true);
127}
128
129/*
130 * nfs4_check_delegation - check if inode has a delegation, do not mark
131 * NFS_DELEGATION_REFERENCED if it has one.
132 */
133int nfs4_check_delegation(struct inode *inode, fmode_t flags)
134{
135 return nfs4_do_check_delegation(inode, flags, false);
136}
137
138static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
139{
140 struct inode *inode = state->inode;
141 struct file_lock *fl;
142 struct file_lock_context *flctx = inode->i_flctx;
143 struct list_head *list;
144 int status = 0;
145
146 if (flctx == NULL)
147 goto out;
148
149 list = &flctx->flc_posix;
150 spin_lock(&flctx->flc_lock);
151restart:
152 list_for_each_entry(fl, list, fl_list) {
153 if (nfs_file_open_context(fl->fl_file)->state != state)
154 continue;
155 spin_unlock(&flctx->flc_lock);
156 status = nfs4_lock_delegation_recall(fl, state, stateid);
157 if (status < 0)
158 goto out;
159 spin_lock(&flctx->flc_lock);
160 }
161 if (list == &flctx->flc_posix) {
162 list = &flctx->flc_flock;
163 goto restart;
164 }
165 spin_unlock(&flctx->flc_lock);
166out:
167 return status;
168}
169
170static int nfs_delegation_claim_opens(struct inode *inode,
171 const nfs4_stateid *stateid, fmode_t type)
172{
173 struct nfs_inode *nfsi = NFS_I(inode);
174 struct nfs_open_context *ctx;
175 struct nfs4_state_owner *sp;
176 struct nfs4_state *state;
177 unsigned int seq;
178 int err;
179
180again:
181 rcu_read_lock();
182 list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
183 state = ctx->state;
184 if (state == NULL)
185 continue;
186 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
187 continue;
188 if (!nfs4_valid_open_stateid(state))
189 continue;
190 if (!nfs4_stateid_match(&state->stateid, stateid))
191 continue;
192 if (!get_nfs_open_context(ctx))
193 continue;
194 rcu_read_unlock();
195 sp = state->owner;
196 /* Block nfs4_proc_unlck */
197 mutex_lock(&sp->so_delegreturn_mutex);
198 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
199 err = nfs4_open_delegation_recall(ctx, state, stateid);
200 if (!err)
201 err = nfs_delegation_claim_locks(state, stateid);
202 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
203 err = -EAGAIN;
204 mutex_unlock(&sp->so_delegreturn_mutex);
205 put_nfs_open_context(ctx);
206 if (err != 0)
207 return err;
208 goto again;
209 }
210 rcu_read_unlock();
211 return 0;
212}
213
214/**
215 * nfs_inode_reclaim_delegation - process a delegation reclaim request
216 * @inode: inode to process
217 * @cred: credential to use for request
218 * @type: delegation type
219 * @stateid: delegation stateid
220 * @pagemod_limit: write delegation "space_limit"
221 *
222 */
223void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
224 fmode_t type,
225 const nfs4_stateid *stateid,
226 unsigned long pagemod_limit)
227{
228 struct nfs_delegation *delegation;
229 const struct cred *oldcred = NULL;
230
231 rcu_read_lock();
232 delegation = rcu_dereference(NFS_I(inode)->delegation);
233 if (delegation != NULL) {
234 spin_lock(&delegation->lock);
235 if (nfs4_is_valid_delegation(delegation, 0)) {
236 nfs4_stateid_copy(&delegation->stateid, stateid);
237 delegation->type = type;
238 delegation->pagemod_limit = pagemod_limit;
239 oldcred = delegation->cred;
240 delegation->cred = get_cred(cred);
241 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
242 &delegation->flags);
243 spin_unlock(&delegation->lock);
244 rcu_read_unlock();
245 put_cred(oldcred);
246 trace_nfs4_reclaim_delegation(inode, type);
247 return;
248 }
249 /* We appear to have raced with a delegation return. */
250 spin_unlock(&delegation->lock);
251 }
252 rcu_read_unlock();
253 nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
254}
255
256static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
257{
258 const struct cred *cred;
259 int res = 0;
260
261 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
262 spin_lock(&delegation->lock);
263 cred = get_cred(delegation->cred);
264 spin_unlock(&delegation->lock);
265 res = nfs4_proc_delegreturn(inode, cred,
266 &delegation->stateid,
267 issync);
268 put_cred(cred);
269 }
270 return res;
271}
272
273static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
274{
275 struct inode *inode = NULL;
276
277 spin_lock(&delegation->lock);
278 if (delegation->inode != NULL)
279 inode = igrab(delegation->inode);
280 if (!inode)
281 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
282 spin_unlock(&delegation->lock);
283 return inode;
284}
285
286static struct nfs_delegation *
287nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
288{
289 struct nfs_delegation *ret = NULL;
290 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
291
292 if (delegation == NULL)
293 goto out;
294 spin_lock(&delegation->lock);
295 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
296 /* Refcount matched in nfs_end_delegation_return() */
297 ret = nfs_get_delegation(delegation);
298 }
299 spin_unlock(&delegation->lock);
300 if (ret)
301 nfs_clear_verifier_delegated(&nfsi->vfs_inode);
302out:
303 return ret;
304}
305
306static struct nfs_delegation *
307nfs_start_delegation_return(struct nfs_inode *nfsi)
308{
309 struct nfs_delegation *delegation;
310
311 rcu_read_lock();
312 delegation = nfs_start_delegation_return_locked(nfsi);
313 rcu_read_unlock();
314 return delegation;
315}
316
317static void
318nfs_abort_delegation_return(struct nfs_delegation *delegation,
319 struct nfs_client *clp)
320{
321
322 spin_lock(&delegation->lock);
323 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
324 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
325 spin_unlock(&delegation->lock);
326 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
327}
328
329static struct nfs_delegation *
330nfs_detach_delegation_locked(struct nfs_inode *nfsi,
331 struct nfs_delegation *delegation,
332 struct nfs_client *clp)
333{
334 struct nfs_delegation *deleg_cur =
335 rcu_dereference_protected(nfsi->delegation,
336 lockdep_is_held(&clp->cl_lock));
337
338 if (deleg_cur == NULL || delegation != deleg_cur)
339 return NULL;
340
341 spin_lock(&delegation->lock);
342 if (!delegation->inode) {
343 spin_unlock(&delegation->lock);
344 return NULL;
345 }
346 list_del_rcu(&delegation->super_list);
347 delegation->inode = NULL;
348 rcu_assign_pointer(nfsi->delegation, NULL);
349 spin_unlock(&delegation->lock);
350 return delegation;
351}
352
353static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
354 struct nfs_delegation *delegation,
355 struct nfs_server *server)
356{
357 struct nfs_client *clp = server->nfs_client;
358
359 spin_lock(&clp->cl_lock);
360 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
361 spin_unlock(&clp->cl_lock);
362 return delegation;
363}
364
365static struct nfs_delegation *
366nfs_inode_detach_delegation(struct inode *inode)
367{
368 struct nfs_inode *nfsi = NFS_I(inode);
369 struct nfs_server *server = NFS_SERVER(inode);
370 struct nfs_delegation *delegation;
371
372 rcu_read_lock();
373 delegation = rcu_dereference(nfsi->delegation);
374 if (delegation != NULL)
375 delegation = nfs_detach_delegation(nfsi, delegation, server);
376 rcu_read_unlock();
377 return delegation;
378}
379
380static void
381nfs_update_delegation_cred(struct nfs_delegation *delegation,
382 const struct cred *cred)
383{
384 const struct cred *old;
385
386 if (cred_fscmp(delegation->cred, cred) != 0) {
387 old = xchg(&delegation->cred, get_cred(cred));
388 put_cred(old);
389 }
390}
391
392static void
393nfs_update_inplace_delegation(struct nfs_delegation *delegation,
394 const struct nfs_delegation *update)
395{
396 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
397 delegation->stateid.seqid = update->stateid.seqid;
398 smp_wmb();
399 delegation->type = update->type;
400 delegation->pagemod_limit = update->pagemod_limit;
401 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
402 delegation->change_attr = update->change_attr;
403 nfs_update_delegation_cred(delegation, update->cred);
404 /* smp_mb__before_atomic() is implicit due to xchg() */
405 clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
406 atomic_long_inc(&nfs_active_delegations);
407 }
408 }
409}
410
411/**
412 * nfs_inode_set_delegation - set up a delegation on an inode
413 * @inode: inode to which delegation applies
414 * @cred: cred to use for subsequent delegation processing
415 * @type: delegation type
416 * @stateid: delegation stateid
417 * @pagemod_limit: write delegation "space_limit"
418 *
419 * Returns zero on success, or a negative errno value.
420 */
421int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
422 fmode_t type,
423 const nfs4_stateid *stateid,
424 unsigned long pagemod_limit)
425{
426 struct nfs_server *server = NFS_SERVER(inode);
427 struct nfs_client *clp = server->nfs_client;
428 struct nfs_inode *nfsi = NFS_I(inode);
429 struct nfs_delegation *delegation, *old_delegation;
430 struct nfs_delegation *freeme = NULL;
431 int status = 0;
432
433 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
434 if (delegation == NULL)
435 return -ENOMEM;
436 nfs4_stateid_copy(&delegation->stateid, stateid);
437 refcount_set(&delegation->refcount, 1);
438 delegation->type = type;
439 delegation->pagemod_limit = pagemod_limit;
440 delegation->change_attr = inode_peek_iversion_raw(inode);
441 delegation->cred = get_cred(cred);
442 delegation->inode = inode;
443 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
444 spin_lock_init(&delegation->lock);
445
446 spin_lock(&clp->cl_lock);
447 old_delegation = rcu_dereference_protected(nfsi->delegation,
448 lockdep_is_held(&clp->cl_lock));
449 if (old_delegation == NULL)
450 goto add_new;
451 /* Is this an update of the existing delegation? */
452 if (nfs4_stateid_match_other(&old_delegation->stateid,
453 &delegation->stateid)) {
454 spin_lock(&old_delegation->lock);
455 nfs_update_inplace_delegation(old_delegation,
456 delegation);
457 spin_unlock(&old_delegation->lock);
458 goto out;
459 }
460 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
461 /*
462 * Deal with broken servers that hand out two
463 * delegations for the same file.
464 * Allow for upgrades to a WRITE delegation, but
465 * nothing else.
466 */
467 dfprintk(FILE, "%s: server %s handed out "
468 "a duplicate delegation!\n",
469 __func__, clp->cl_hostname);
470 if (delegation->type == old_delegation->type ||
471 !(delegation->type & FMODE_WRITE)) {
472 freeme = delegation;
473 delegation = NULL;
474 goto out;
475 }
476 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
477 &old_delegation->flags))
478 goto out;
479 }
480 freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
481 if (freeme == NULL)
482 goto out;
483add_new:
484 list_add_tail_rcu(&delegation->super_list, &server->delegations);
485 rcu_assign_pointer(nfsi->delegation, delegation);
486 delegation = NULL;
487
488 atomic_long_inc(&nfs_active_delegations);
489
490 trace_nfs4_set_delegation(inode, type);
491
492 spin_lock(&inode->i_lock);
493 if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
494 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
495 spin_unlock(&inode->i_lock);
496out:
497 spin_unlock(&clp->cl_lock);
498 if (delegation != NULL)
499 __nfs_free_delegation(delegation);
500 if (freeme != NULL) {
501 nfs_do_return_delegation(inode, freeme, 0);
502 nfs_free_delegation(freeme);
503 }
504 return status;
505}
506
507/*
508 * Basic procedure for returning a delegation to the server
509 */
510static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
511{
512 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
513 int err = 0;
514
515 if (delegation == NULL)
516 return 0;
517 do {
518 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
519 break;
520 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
521 delegation->type);
522 if (!issync || err != -EAGAIN)
523 break;
524 /*
525 * Guard against state recovery
526 */
527 err = nfs4_wait_clnt_recover(clp);
528 } while (err == 0);
529
530 if (err) {
531 nfs_abort_delegation_return(delegation, clp);
532 goto out;
533 }
534
535 err = nfs_do_return_delegation(inode, delegation, issync);
536out:
537 /* Refcount matched in nfs_start_delegation_return_locked() */
538 nfs_put_delegation(delegation);
539 return err;
540}
541
542static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
543{
544 bool ret = false;
545
546 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
547 ret = true;
548 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
549 struct inode *inode;
550
551 spin_lock(&delegation->lock);
552 inode = delegation->inode;
553 if (inode && list_empty(&NFS_I(inode)->open_files))
554 ret = true;
555 spin_unlock(&delegation->lock);
556 }
557 if (ret)
558 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
559 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
560 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
561 ret = false;
562
563 return ret;
564}
565
566static int nfs_server_return_marked_delegations(struct nfs_server *server,
567 void __always_unused *data)
568{
569 struct nfs_delegation *delegation;
570 struct nfs_delegation *prev;
571 struct inode *inode;
572 struct inode *place_holder = NULL;
573 struct nfs_delegation *place_holder_deleg = NULL;
574 int err = 0;
575
576restart:
577 /*
578 * To avoid quadratic looping we hold a reference
579 * to an inode place_holder. Each time we restart, we
580 * list delegation in the server from the delegations
581 * of that inode.
582 * prev is an RCU-protected pointer to a delegation which
583 * wasn't marked for return and might be a good choice for
584 * the next place_holder.
585 */
586 prev = NULL;
587 delegation = NULL;
588 rcu_read_lock();
589 if (place_holder)
590 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
591 if (!delegation || delegation != place_holder_deleg)
592 delegation = list_entry_rcu(server->delegations.next,
593 struct nfs_delegation, super_list);
594 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
595 struct inode *to_put = NULL;
596
597 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
598 continue;
599 if (!nfs_delegation_need_return(delegation)) {
600 if (nfs4_is_valid_delegation(delegation, 0))
601 prev = delegation;
602 continue;
603 }
604
605 if (prev) {
606 struct inode *tmp = nfs_delegation_grab_inode(prev);
607 if (tmp) {
608 to_put = place_holder;
609 place_holder = tmp;
610 place_holder_deleg = prev;
611 }
612 }
613
614 inode = nfs_delegation_grab_inode(delegation);
615 if (inode == NULL) {
616 rcu_read_unlock();
617 iput(to_put);
618 goto restart;
619 }
620 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
621 rcu_read_unlock();
622
623 iput(to_put);
624
625 err = nfs_end_delegation_return(inode, delegation, 0);
626 iput(inode);
627 cond_resched();
628 if (!err)
629 goto restart;
630 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
631 goto out;
632 }
633 rcu_read_unlock();
634out:
635 iput(place_holder);
636 return err;
637}
638
639/**
640 * nfs_client_return_marked_delegations - return previously marked delegations
641 * @clp: nfs_client to process
642 *
643 * Note that this function is designed to be called by the state
644 * manager thread. For this reason, it cannot flush the dirty data,
645 * since that could deadlock in case of a state recovery error.
646 *
647 * Returns zero on success, or a negative errno value.
648 */
649int nfs_client_return_marked_delegations(struct nfs_client *clp)
650{
651 return nfs_client_for_each_server(clp,
652 nfs_server_return_marked_delegations, NULL);
653}
654
655/**
656 * nfs_inode_evict_delegation - return delegation, don't reclaim opens
657 * @inode: inode to process
658 *
659 * Does not protect against delegation reclaims, therefore really only safe
660 * to be called from nfs4_clear_inode(). Guaranteed to always free
661 * the delegation structure.
662 */
663void nfs_inode_evict_delegation(struct inode *inode)
664{
665 struct nfs_delegation *delegation;
666
667 delegation = nfs_inode_detach_delegation(inode);
668 if (delegation != NULL) {
669 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
670 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
671 nfs_do_return_delegation(inode, delegation, 1);
672 nfs_free_delegation(delegation);
673 }
674}
675
676/**
677 * nfs_inode_return_delegation - synchronously return a delegation
678 * @inode: inode to process
679 *
680 * This routine will always flush any dirty data to disk on the
681 * assumption that if we need to return the delegation, then
682 * we should stop caching.
683 *
684 * Returns zero on success, or a negative errno value.
685 */
686int nfs4_inode_return_delegation(struct inode *inode)
687{
688 struct nfs_inode *nfsi = NFS_I(inode);
689 struct nfs_delegation *delegation;
690 int err = 0;
691
692 nfs_wb_all(inode);
693 delegation = nfs_start_delegation_return(nfsi);
694 if (delegation != NULL)
695 err = nfs_end_delegation_return(inode, delegation, 1);
696 return err;
697}
698
699/**
700 * nfs_inode_return_delegation_on_close - asynchronously return a delegation
701 * @inode: inode to process
702 *
703 * This routine is called on file close in order to determine if the
704 * inode delegation needs to be returned immediately.
705 */
706void nfs4_inode_return_delegation_on_close(struct inode *inode)
707{
708 struct nfs_delegation *delegation;
709 struct nfs_delegation *ret = NULL;
710
711 if (!inode)
712 return;
713 rcu_read_lock();
714 delegation = nfs4_get_valid_delegation(inode);
715 if (!delegation)
716 goto out;
717 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
718 atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
719 spin_lock(&delegation->lock);
720 if (delegation->inode &&
721 list_empty(&NFS_I(inode)->open_files) &&
722 !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
723 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
724 /* Refcount matched in nfs_end_delegation_return() */
725 ret = nfs_get_delegation(delegation);
726 }
727 spin_unlock(&delegation->lock);
728 if (ret)
729 nfs_clear_verifier_delegated(inode);
730 }
731out:
732 rcu_read_unlock();
733 nfs_end_delegation_return(inode, ret, 0);
734}
735
736/**
737 * nfs4_inode_make_writeable
738 * @inode: pointer to inode
739 *
740 * Make the inode writeable by returning the delegation if necessary
741 *
742 * Returns zero on success, or a negative errno value.
743 */
744int nfs4_inode_make_writeable(struct inode *inode)
745{
746 struct nfs_delegation *delegation;
747
748 rcu_read_lock();
749 delegation = nfs4_get_valid_delegation(inode);
750 if (delegation == NULL ||
751 (nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
752 (delegation->type & FMODE_WRITE))) {
753 rcu_read_unlock();
754 return 0;
755 }
756 rcu_read_unlock();
757 return nfs4_inode_return_delegation(inode);
758}
759
760static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
761 struct nfs_delegation *delegation)
762{
763 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
764 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
765}
766
767static void nfs_mark_return_delegation(struct nfs_server *server,
768 struct nfs_delegation *delegation)
769{
770 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
771 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
772}
773
774static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
775{
776 struct nfs_delegation *delegation;
777 bool ret = false;
778
779 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
780 nfs_mark_return_delegation(server, delegation);
781 ret = true;
782 }
783 return ret;
784}
785
786static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
787{
788 struct nfs_server *server;
789
790 rcu_read_lock();
791 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
792 nfs_server_mark_return_all_delegations(server);
793 rcu_read_unlock();
794}
795
796static void nfs_delegation_run_state_manager(struct nfs_client *clp)
797{
798 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
799 nfs4_schedule_state_manager(clp);
800}
801
802/**
803 * nfs_expire_all_delegations
804 * @clp: client to process
805 *
806 */
807void nfs_expire_all_delegations(struct nfs_client *clp)
808{
809 nfs_client_mark_return_all_delegations(clp);
810 nfs_delegation_run_state_manager(clp);
811}
812
813/**
814 * nfs_super_return_all_delegations - return delegations for one superblock
815 * @server: pointer to nfs_server to process
816 *
817 */
818void nfs_server_return_all_delegations(struct nfs_server *server)
819{
820 struct nfs_client *clp = server->nfs_client;
821 bool need_wait;
822
823 if (clp == NULL)
824 return;
825
826 rcu_read_lock();
827 need_wait = nfs_server_mark_return_all_delegations(server);
828 rcu_read_unlock();
829
830 if (need_wait) {
831 nfs4_schedule_state_manager(clp);
832 nfs4_wait_clnt_recover(clp);
833 }
834}
835
836static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
837 fmode_t flags)
838{
839 struct nfs_delegation *delegation;
840
841 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
842 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
843 continue;
844 if (delegation->type & flags)
845 nfs_mark_return_if_closed_delegation(server, delegation);
846 }
847}
848
849static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
850 fmode_t flags)
851{
852 struct nfs_server *server;
853
854 rcu_read_lock();
855 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
856 nfs_mark_return_unused_delegation_types(server, flags);
857 rcu_read_unlock();
858}
859
860static void nfs_revoke_delegation(struct inode *inode,
861 const nfs4_stateid *stateid)
862{
863 struct nfs_delegation *delegation;
864 nfs4_stateid tmp;
865 bool ret = false;
866
867 rcu_read_lock();
868 delegation = rcu_dereference(NFS_I(inode)->delegation);
869 if (delegation == NULL)
870 goto out;
871 if (stateid == NULL) {
872 nfs4_stateid_copy(&tmp, &delegation->stateid);
873 stateid = &tmp;
874 } else {
875 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
876 goto out;
877 spin_lock(&delegation->lock);
878 if (stateid->seqid) {
879 if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
880 spin_unlock(&delegation->lock);
881 goto out;
882 }
883 delegation->stateid.seqid = stateid->seqid;
884 }
885 spin_unlock(&delegation->lock);
886 }
887 nfs_mark_delegation_revoked(delegation);
888 ret = true;
889out:
890 rcu_read_unlock();
891 if (ret)
892 nfs_inode_find_state_and_recover(inode, stateid);
893}
894
895void nfs_remove_bad_delegation(struct inode *inode,
896 const nfs4_stateid *stateid)
897{
898 nfs_revoke_delegation(inode, stateid);
899}
900EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
901
902void nfs_delegation_mark_returned(struct inode *inode,
903 const nfs4_stateid *stateid)
904{
905 struct nfs_delegation *delegation;
906
907 if (!inode)
908 return;
909
910 rcu_read_lock();
911 delegation = rcu_dereference(NFS_I(inode)->delegation);
912 if (!delegation)
913 goto out_rcu_unlock;
914
915 spin_lock(&delegation->lock);
916 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
917 goto out_spin_unlock;
918 if (stateid->seqid) {
919 /* If delegation->stateid is newer, dont mark as returned */
920 if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
921 goto out_clear_returning;
922 if (delegation->stateid.seqid != stateid->seqid)
923 delegation->stateid.seqid = stateid->seqid;
924 }
925
926 nfs_mark_delegation_revoked(delegation);
927
928out_clear_returning:
929 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
930out_spin_unlock:
931 spin_unlock(&delegation->lock);
932out_rcu_unlock:
933 rcu_read_unlock();
934
935 nfs_inode_find_state_and_recover(inode, stateid);
936}
937
938/**
939 * nfs_expire_unused_delegation_types
940 * @clp: client to process
941 * @flags: delegation types to expire
942 *
943 */
944void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
945{
946 nfs_client_mark_return_unused_delegation_types(clp, flags);
947 nfs_delegation_run_state_manager(clp);
948}
949
950static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
951{
952 struct nfs_delegation *delegation;
953
954 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
955 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
956 continue;
957 nfs_mark_return_if_closed_delegation(server, delegation);
958 }
959}
960
961/**
962 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
963 * @clp: nfs_client to process
964 *
965 */
966void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
967{
968 struct nfs_server *server;
969
970 rcu_read_lock();
971 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
972 nfs_mark_return_unreferenced_delegations(server);
973 rcu_read_unlock();
974
975 nfs_delegation_run_state_manager(clp);
976}
977
978/**
979 * nfs_async_inode_return_delegation - asynchronously return a delegation
980 * @inode: inode to process
981 * @stateid: state ID information
982 *
983 * Returns zero on success, or a negative errno value.
984 */
985int nfs_async_inode_return_delegation(struct inode *inode,
986 const nfs4_stateid *stateid)
987{
988 struct nfs_server *server = NFS_SERVER(inode);
989 struct nfs_client *clp = server->nfs_client;
990 struct nfs_delegation *delegation;
991
992 rcu_read_lock();
993 delegation = nfs4_get_valid_delegation(inode);
994 if (delegation == NULL)
995 goto out_enoent;
996 if (stateid != NULL &&
997 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
998 goto out_enoent;
999 nfs_mark_return_delegation(server, delegation);
1000 rcu_read_unlock();
1001
1002 nfs_delegation_run_state_manager(clp);
1003 return 0;
1004out_enoent:
1005 rcu_read_unlock();
1006 return -ENOENT;
1007}
1008
1009static struct inode *
1010nfs_delegation_find_inode_server(struct nfs_server *server,
1011 const struct nfs_fh *fhandle)
1012{
1013 struct nfs_delegation *delegation;
1014 struct inode *freeme, *res = NULL;
1015
1016 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1017 spin_lock(&delegation->lock);
1018 if (delegation->inode != NULL &&
1019 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1020 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1021 freeme = igrab(delegation->inode);
1022 if (freeme && nfs_sb_active(freeme->i_sb))
1023 res = freeme;
1024 spin_unlock(&delegation->lock);
1025 if (res != NULL)
1026 return res;
1027 if (freeme) {
1028 rcu_read_unlock();
1029 iput(freeme);
1030 rcu_read_lock();
1031 }
1032 return ERR_PTR(-EAGAIN);
1033 }
1034 spin_unlock(&delegation->lock);
1035 }
1036 return ERR_PTR(-ENOENT);
1037}
1038
1039/**
1040 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1041 * @clp: client state handle
1042 * @fhandle: filehandle from a delegation recall
1043 *
1044 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1045 * cannot be found.
1046 */
1047struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1048 const struct nfs_fh *fhandle)
1049{
1050 struct nfs_server *server;
1051 struct inode *res;
1052
1053 rcu_read_lock();
1054 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1055 res = nfs_delegation_find_inode_server(server, fhandle);
1056 if (res != ERR_PTR(-ENOENT)) {
1057 rcu_read_unlock();
1058 return res;
1059 }
1060 }
1061 rcu_read_unlock();
1062 return ERR_PTR(-ENOENT);
1063}
1064
1065static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1066{
1067 struct nfs_delegation *delegation;
1068
1069 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1070 /*
1071 * If the delegation may have been admin revoked, then we
1072 * cannot reclaim it.
1073 */
1074 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1075 continue;
1076 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1077 }
1078}
1079
1080/**
1081 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1082 * @clp: nfs_client to process
1083 *
1084 */
1085void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1086{
1087 struct nfs_server *server;
1088
1089 rcu_read_lock();
1090 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1091 nfs_delegation_mark_reclaim_server(server);
1092 rcu_read_unlock();
1093}
1094
1095static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1096 void __always_unused *data)
1097{
1098 struct nfs_delegation *delegation;
1099 struct inode *inode;
1100restart:
1101 rcu_read_lock();
1102restart_locked:
1103 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1104 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1105 &delegation->flags) ||
1106 test_bit(NFS_DELEGATION_RETURNING,
1107 &delegation->flags) ||
1108 test_bit(NFS_DELEGATION_NEED_RECLAIM,
1109 &delegation->flags) == 0)
1110 continue;
1111 inode = nfs_delegation_grab_inode(delegation);
1112 if (inode == NULL)
1113 goto restart_locked;
1114 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
1115 rcu_read_unlock();
1116 if (delegation != NULL) {
1117 if (nfs_detach_delegation(NFS_I(inode), delegation,
1118 server) != NULL)
1119 nfs_free_delegation(delegation);
1120 /* Match nfs_start_delegation_return_locked */
1121 nfs_put_delegation(delegation);
1122 }
1123 iput(inode);
1124 cond_resched();
1125 goto restart;
1126 }
1127 rcu_read_unlock();
1128 return 0;
1129}
1130
1131/**
1132 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1133 * @clp: nfs_client to process
1134 *
1135 */
1136void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1137{
1138 nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
1139 NULL);
1140}
1141
1142static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1143{
1144 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1145 BIT(NFS4CLNT_LEASE_EXPIRED) |
1146 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1147}
1148
1149static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1150 struct nfs_delegation *delegation)
1151{
1152 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1153 return;
1154 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1155 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1156 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1157}
1158
1159static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1160 struct inode *inode)
1161{
1162 struct nfs_delegation *delegation;
1163
1164 rcu_read_lock();
1165 delegation = rcu_dereference(NFS_I(inode)->delegation);
1166 if (delegation)
1167 nfs_mark_test_expired_delegation(server, delegation);
1168 rcu_read_unlock();
1169
1170}
1171
1172static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1173{
1174 struct nfs_delegation *delegation;
1175
1176 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1177 nfs_mark_test_expired_delegation(server, delegation);
1178}
1179
1180/**
1181 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1182 * @clp: nfs_client to process
1183 *
1184 * Iterates through all the delegations associated with this server and
1185 * marks them as needing to be checked for validity.
1186 */
1187void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1188{
1189 struct nfs_server *server;
1190
1191 rcu_read_lock();
1192 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1193 nfs_delegation_mark_test_expired_server(server);
1194 rcu_read_unlock();
1195}
1196
1197/**
1198 * nfs_test_expired_all_delegations - test all delegations for a client
1199 * @clp: nfs_client to process
1200 *
1201 * Helper for handling "recallable state revoked" status from server.
1202 */
1203void nfs_test_expired_all_delegations(struct nfs_client *clp)
1204{
1205 nfs_mark_test_expired_all_delegations(clp);
1206 nfs4_schedule_state_manager(clp);
1207}
1208
1209static void
1210nfs_delegation_test_free_expired(struct inode *inode,
1211 nfs4_stateid *stateid,
1212 const struct cred *cred)
1213{
1214 struct nfs_server *server = NFS_SERVER(inode);
1215 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1216 int status;
1217
1218 if (!cred)
1219 return;
1220 status = ops->test_and_free_expired(server, stateid, cred);
1221 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1222 nfs_remove_bad_delegation(inode, stateid);
1223}
1224
1225static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1226 void __always_unused *data)
1227{
1228 struct nfs_delegation *delegation;
1229 struct inode *inode;
1230 const struct cred *cred;
1231 nfs4_stateid stateid;
1232restart:
1233 rcu_read_lock();
1234restart_locked:
1235 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1236 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1237 &delegation->flags) ||
1238 test_bit(NFS_DELEGATION_RETURNING,
1239 &delegation->flags) ||
1240 test_bit(NFS_DELEGATION_TEST_EXPIRED,
1241 &delegation->flags) == 0)
1242 continue;
1243 inode = nfs_delegation_grab_inode(delegation);
1244 if (inode == NULL)
1245 goto restart_locked;
1246 spin_lock(&delegation->lock);
1247 cred = get_cred_rcu(delegation->cred);
1248 nfs4_stateid_copy(&stateid, &delegation->stateid);
1249 spin_unlock(&delegation->lock);
1250 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1251 rcu_read_unlock();
1252 nfs_delegation_test_free_expired(inode, &stateid, cred);
1253 put_cred(cred);
1254 if (!nfs4_server_rebooted(server->nfs_client)) {
1255 iput(inode);
1256 cond_resched();
1257 goto restart;
1258 }
1259 nfs_inode_mark_test_expired_delegation(server,inode);
1260 iput(inode);
1261 return -EAGAIN;
1262 }
1263 rcu_read_unlock();
1264 return 0;
1265}
1266
1267/**
1268 * nfs_reap_expired_delegations - reap expired delegations
1269 * @clp: nfs_client to process
1270 *
1271 * Iterates through all the delegations associated with this server and
1272 * checks if they have may have been revoked. This function is usually
1273 * expected to be called in cases where the server may have lost its
1274 * lease.
1275 */
1276void nfs_reap_expired_delegations(struct nfs_client *clp)
1277{
1278 nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
1279 NULL);
1280}
1281
1282void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1283 const nfs4_stateid *stateid)
1284{
1285 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1286 struct nfs_delegation *delegation;
1287 bool found = false;
1288
1289 rcu_read_lock();
1290 delegation = rcu_dereference(NFS_I(inode)->delegation);
1291 if (delegation &&
1292 nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
1293 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1294 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1295 found = true;
1296 }
1297 rcu_read_unlock();
1298 if (found)
1299 nfs4_schedule_state_manager(clp);
1300}
1301
1302/**
1303 * nfs_delegations_present - check for existence of delegations
1304 * @clp: client state handle
1305 *
1306 * Returns one if there are any nfs_delegation structures attached
1307 * to this nfs_client.
1308 */
1309int nfs_delegations_present(struct nfs_client *clp)
1310{
1311 struct nfs_server *server;
1312 int ret = 0;
1313
1314 rcu_read_lock();
1315 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1316 if (!list_empty(&server->delegations)) {
1317 ret = 1;
1318 break;
1319 }
1320 rcu_read_unlock();
1321 return ret;
1322}
1323
1324/**
1325 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1326 * @dst: stateid to refresh
1327 * @inode: inode to check
1328 *
1329 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1330 * that matches our delegation stateid. Otherwise "false" is returned.
1331 */
1332bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1333{
1334 struct nfs_delegation *delegation;
1335 bool ret = false;
1336 if (!inode)
1337 goto out;
1338
1339 rcu_read_lock();
1340 delegation = rcu_dereference(NFS_I(inode)->delegation);
1341 if (delegation != NULL &&
1342 nfs4_stateid_match_other(dst, &delegation->stateid) &&
1343 nfs4_stateid_is_newer(&delegation->stateid, dst) &&
1344 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1345 dst->seqid = delegation->stateid.seqid;
1346 ret = true;
1347 }
1348 rcu_read_unlock();
1349out:
1350 return ret;
1351}
1352
1353/**
1354 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1355 * @inode: inode to check
1356 * @flags: delegation type requirement
1357 * @dst: stateid data structure to fill in
1358 * @cred: optional argument to retrieve credential
1359 *
1360 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1361 * otherwise "false" is returned.
1362 */
1363bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1364 nfs4_stateid *dst, const struct cred **cred)
1365{
1366 struct nfs_inode *nfsi = NFS_I(inode);
1367 struct nfs_delegation *delegation;
1368 bool ret = false;
1369
1370 flags &= FMODE_READ|FMODE_WRITE;
1371 rcu_read_lock();
1372 delegation = rcu_dereference(nfsi->delegation);
1373 if (!delegation)
1374 goto out;
1375 spin_lock(&delegation->lock);
1376 ret = nfs4_is_valid_delegation(delegation, flags);
1377 if (ret) {
1378 nfs4_stateid_copy(dst, &delegation->stateid);
1379 nfs_mark_delegation_referenced(delegation);
1380 if (cred)
1381 *cred = get_cred(delegation->cred);
1382 }
1383 spin_unlock(&delegation->lock);
1384out:
1385 rcu_read_unlock();
1386 return ret;
1387}
1388
1389/**
1390 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1391 * @inode: inode to check
1392 *
1393 * This function checks the number of outstanding writes to the file
1394 * against the delegation 'space_limit' field to see if
1395 * the spec requires us to flush the file on close.
1396 */
1397bool nfs4_delegation_flush_on_close(const struct inode *inode)
1398{
1399 struct nfs_inode *nfsi = NFS_I(inode);
1400 struct nfs_delegation *delegation;
1401 bool ret = true;
1402
1403 rcu_read_lock();
1404 delegation = rcu_dereference(nfsi->delegation);
1405 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1406 goto out;
1407 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1408 ret = false;
1409out:
1410 rcu_read_unlock();
1411 return ret;
1412}
1413
1414module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);