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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 void nfs_mark_return_delegation(struct nfs_server *server,
79 struct nfs_delegation *delegation)
80{
81 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
82 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
83}
84
85static bool nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
86 fmode_t type)
87{
88 if (delegation != NULL && (delegation->type & type) == type &&
89 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
90 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
91 return true;
92 return false;
93}
94
95struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
96{
97 struct nfs_delegation *delegation;
98
99 delegation = rcu_dereference(NFS_I(inode)->delegation);
100 if (nfs4_is_valid_delegation(delegation, 0))
101 return delegation;
102 return NULL;
103}
104
105static int nfs4_do_check_delegation(struct inode *inode, fmode_t type,
106 int flags, bool mark)
107{
108 struct nfs_delegation *delegation;
109 int ret = 0;
110
111 type &= FMODE_READ|FMODE_WRITE;
112 rcu_read_lock();
113 delegation = rcu_dereference(NFS_I(inode)->delegation);
114 if (nfs4_is_valid_delegation(delegation, type)) {
115 if (mark)
116 nfs_mark_delegation_referenced(delegation);
117 ret = 1;
118 if ((flags & NFS_DELEGATION_FLAG_TIME) &&
119 !test_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags))
120 ret = 0;
121 }
122 rcu_read_unlock();
123 return ret;
124}
125/**
126 * nfs4_have_delegation - check if inode has a delegation, mark it
127 * NFS_DELEGATION_REFERENCED if there is one.
128 * @inode: inode to check
129 * @type: delegation types to check for
130 * @flags: various modifiers
131 *
132 * Returns one if inode has the indicated delegation, otherwise zero.
133 */
134int nfs4_have_delegation(struct inode *inode, fmode_t type, int flags)
135{
136 return nfs4_do_check_delegation(inode, type, flags, true);
137}
138
139/*
140 * nfs4_check_delegation - check if inode has a delegation, do not mark
141 * NFS_DELEGATION_REFERENCED if it has one.
142 */
143int nfs4_check_delegation(struct inode *inode, fmode_t type)
144{
145 return nfs4_do_check_delegation(inode, type, 0, false);
146}
147
148static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
149{
150 struct inode *inode = state->inode;
151 struct file_lock *fl;
152 struct file_lock_context *flctx = locks_inode_context(inode);
153 struct list_head *list;
154 int status = 0;
155
156 if (flctx == NULL)
157 goto out;
158
159 list = &flctx->flc_posix;
160 spin_lock(&flctx->flc_lock);
161restart:
162 for_each_file_lock(fl, list) {
163 if (nfs_file_open_context(fl->c.flc_file)->state != state)
164 continue;
165 spin_unlock(&flctx->flc_lock);
166 status = nfs4_lock_delegation_recall(fl, state, stateid);
167 if (status < 0)
168 goto out;
169 spin_lock(&flctx->flc_lock);
170 }
171 if (list == &flctx->flc_posix) {
172 list = &flctx->flc_flock;
173 goto restart;
174 }
175 spin_unlock(&flctx->flc_lock);
176out:
177 return status;
178}
179
180static int nfs_delegation_claim_opens(struct inode *inode,
181 const nfs4_stateid *stateid, fmode_t type)
182{
183 struct nfs_inode *nfsi = NFS_I(inode);
184 struct nfs_open_context *ctx;
185 struct nfs4_state_owner *sp;
186 struct nfs4_state *state;
187 int err;
188
189again:
190 rcu_read_lock();
191 list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
192 state = ctx->state;
193 if (state == NULL)
194 continue;
195 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
196 continue;
197 if (!nfs4_valid_open_stateid(state))
198 continue;
199 if (!nfs4_stateid_match(&state->stateid, stateid))
200 continue;
201 if (!get_nfs_open_context(ctx))
202 continue;
203 rcu_read_unlock();
204 sp = state->owner;
205 /* Block nfs4_proc_unlck */
206 mutex_lock(&sp->so_delegreturn_mutex);
207 err = nfs4_open_delegation_recall(ctx, state, stateid);
208 if (!err)
209 err = nfs_delegation_claim_locks(state, stateid);
210 mutex_unlock(&sp->so_delegreturn_mutex);
211 put_nfs_open_context(ctx);
212 if (err != 0)
213 return err;
214 goto again;
215 }
216 rcu_read_unlock();
217 return 0;
218}
219
220/**
221 * nfs_inode_reclaim_delegation - process a delegation reclaim request
222 * @inode: inode to process
223 * @cred: credential to use for request
224 * @type: delegation type
225 * @stateid: delegation stateid
226 * @pagemod_limit: write delegation "space_limit"
227 * @deleg_type: raw delegation type
228 *
229 */
230void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
231 fmode_t type, const nfs4_stateid *stateid,
232 unsigned long pagemod_limit, u32 deleg_type)
233{
234 struct nfs_delegation *delegation;
235 const struct cred *oldcred = NULL;
236
237 rcu_read_lock();
238 delegation = rcu_dereference(NFS_I(inode)->delegation);
239 if (delegation != NULL) {
240 spin_lock(&delegation->lock);
241 nfs4_stateid_copy(&delegation->stateid, stateid);
242 delegation->type = type;
243 delegation->pagemod_limit = pagemod_limit;
244 oldcred = delegation->cred;
245 delegation->cred = get_cred(cred);
246 switch (deleg_type) {
247 case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:
248 case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:
249 set_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);
250 break;
251 default:
252 clear_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);
253 }
254 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
255 if (test_and_clear_bit(NFS_DELEGATION_REVOKED,
256 &delegation->flags))
257 atomic_long_inc(&nfs_active_delegations);
258 spin_unlock(&delegation->lock);
259 rcu_read_unlock();
260 put_cred(oldcred);
261 trace_nfs4_reclaim_delegation(inode, type);
262 } else {
263 rcu_read_unlock();
264 nfs_inode_set_delegation(inode, cred, type, stateid,
265 pagemod_limit, deleg_type);
266 }
267}
268
269static int nfs_do_return_delegation(struct inode *inode,
270 struct nfs_delegation *delegation,
271 int issync)
272{
273 const struct cred *cred;
274 int res = 0;
275
276 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
277 spin_lock(&delegation->lock);
278 cred = get_cred(delegation->cred);
279 spin_unlock(&delegation->lock);
280 res = nfs4_proc_delegreturn(inode, cred, &delegation->stateid,
281 delegation, issync);
282 put_cred(cred);
283 }
284 return res;
285}
286
287static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
288{
289 struct inode *inode = NULL;
290
291 spin_lock(&delegation->lock);
292 if (delegation->inode != NULL)
293 inode = igrab(delegation->inode);
294 if (!inode)
295 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
296 spin_unlock(&delegation->lock);
297 return inode;
298}
299
300static struct nfs_delegation *
301nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
302{
303 struct nfs_delegation *ret = NULL;
304 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
305
306 if (delegation == NULL)
307 goto out;
308 spin_lock(&delegation->lock);
309 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
310 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
311 /* Refcount matched in nfs_end_delegation_return() */
312 ret = nfs_get_delegation(delegation);
313 }
314 spin_unlock(&delegation->lock);
315 if (ret)
316 nfs_clear_verifier_delegated(&nfsi->vfs_inode);
317out:
318 return ret;
319}
320
321static struct nfs_delegation *
322nfs_start_delegation_return(struct nfs_inode *nfsi)
323{
324 struct nfs_delegation *delegation;
325
326 rcu_read_lock();
327 delegation = nfs_start_delegation_return_locked(nfsi);
328 rcu_read_unlock();
329 return delegation;
330}
331
332static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
333 struct nfs_client *clp, int err)
334{
335
336 spin_lock(&delegation->lock);
337 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
338 if (err == -EAGAIN) {
339 set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
340 set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state);
341 }
342 spin_unlock(&delegation->lock);
343}
344
345static struct nfs_delegation *
346nfs_detach_delegation_locked(struct nfs_inode *nfsi,
347 struct nfs_delegation *delegation,
348 struct nfs_client *clp)
349{
350 struct nfs_delegation *deleg_cur =
351 rcu_dereference_protected(nfsi->delegation,
352 lockdep_is_held(&clp->cl_lock));
353
354 if (deleg_cur == NULL || delegation != deleg_cur)
355 return NULL;
356
357 spin_lock(&delegation->lock);
358 if (!delegation->inode) {
359 spin_unlock(&delegation->lock);
360 return NULL;
361 }
362 list_del_rcu(&delegation->super_list);
363 delegation->inode = NULL;
364 rcu_assign_pointer(nfsi->delegation, NULL);
365 spin_unlock(&delegation->lock);
366 return delegation;
367}
368
369static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
370 struct nfs_delegation *delegation,
371 struct nfs_server *server)
372{
373 struct nfs_client *clp = server->nfs_client;
374
375 spin_lock(&clp->cl_lock);
376 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
377 spin_unlock(&clp->cl_lock);
378 return delegation;
379}
380
381static struct nfs_delegation *
382nfs_inode_detach_delegation(struct inode *inode)
383{
384 struct nfs_inode *nfsi = NFS_I(inode);
385 struct nfs_server *server = NFS_SERVER(inode);
386 struct nfs_delegation *delegation;
387
388 rcu_read_lock();
389 delegation = rcu_dereference(nfsi->delegation);
390 if (delegation != NULL)
391 delegation = nfs_detach_delegation(nfsi, delegation, server);
392 rcu_read_unlock();
393 return delegation;
394}
395
396static void
397nfs_update_delegation_cred(struct nfs_delegation *delegation,
398 const struct cred *cred)
399{
400 const struct cred *old;
401
402 if (cred_fscmp(delegation->cred, cred) != 0) {
403 old = xchg(&delegation->cred, get_cred(cred));
404 put_cred(old);
405 }
406}
407
408static void
409nfs_update_inplace_delegation(struct nfs_delegation *delegation,
410 const struct nfs_delegation *update)
411{
412 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
413 delegation->stateid.seqid = update->stateid.seqid;
414 smp_wmb();
415 delegation->type = update->type;
416 delegation->pagemod_limit = update->pagemod_limit;
417 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
418 delegation->change_attr = update->change_attr;
419 nfs_update_delegation_cred(delegation, update->cred);
420 /* smp_mb__before_atomic() is implicit due to xchg() */
421 clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
422 atomic_long_inc(&nfs_active_delegations);
423 }
424 }
425}
426
427/**
428 * nfs_inode_set_delegation - set up a delegation on an inode
429 * @inode: inode to which delegation applies
430 * @cred: cred to use for subsequent delegation processing
431 * @type: delegation type
432 * @stateid: delegation stateid
433 * @pagemod_limit: write delegation "space_limit"
434 * @deleg_type: raw delegation type
435 *
436 * Returns zero on success, or a negative errno value.
437 */
438int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
439 fmode_t type, const nfs4_stateid *stateid,
440 unsigned long pagemod_limit, u32 deleg_type)
441{
442 struct nfs_server *server = NFS_SERVER(inode);
443 struct nfs_client *clp = server->nfs_client;
444 struct nfs_inode *nfsi = NFS_I(inode);
445 struct nfs_delegation *delegation, *old_delegation;
446 struct nfs_delegation *freeme = NULL;
447 int status = 0;
448
449 delegation = kmalloc(sizeof(*delegation), GFP_KERNEL_ACCOUNT);
450 if (delegation == NULL)
451 return -ENOMEM;
452 nfs4_stateid_copy(&delegation->stateid, stateid);
453 refcount_set(&delegation->refcount, 1);
454 delegation->type = type;
455 delegation->pagemod_limit = pagemod_limit;
456 delegation->change_attr = inode_peek_iversion_raw(inode);
457 delegation->cred = get_cred(cred);
458 delegation->inode = inode;
459 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
460 switch (deleg_type) {
461 case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:
462 case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:
463 delegation->flags |= BIT(NFS_DELEGATION_DELEGTIME);
464 }
465 delegation->test_gen = 0;
466 spin_lock_init(&delegation->lock);
467
468 spin_lock(&clp->cl_lock);
469 old_delegation = rcu_dereference_protected(nfsi->delegation,
470 lockdep_is_held(&clp->cl_lock));
471 if (old_delegation == NULL)
472 goto add_new;
473 /* Is this an update of the existing delegation? */
474 if (nfs4_stateid_match_other(&old_delegation->stateid,
475 &delegation->stateid)) {
476 spin_lock(&old_delegation->lock);
477 nfs_update_inplace_delegation(old_delegation,
478 delegation);
479 spin_unlock(&old_delegation->lock);
480 goto out;
481 }
482 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
483 /*
484 * Deal with broken servers that hand out two
485 * delegations for the same file.
486 * Allow for upgrades to a WRITE delegation, but
487 * nothing else.
488 */
489 dfprintk(FILE, "%s: server %s handed out "
490 "a duplicate delegation!\n",
491 __func__, clp->cl_hostname);
492 if (delegation->type == old_delegation->type ||
493 !(delegation->type & FMODE_WRITE)) {
494 freeme = delegation;
495 delegation = NULL;
496 goto out;
497 }
498 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
499 &old_delegation->flags))
500 goto out;
501 }
502 freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
503 if (freeme == NULL)
504 goto out;
505add_new:
506 /*
507 * If we didn't revalidate the change attribute before setting
508 * the delegation, then pre-emptively ask for a full attribute
509 * cache revalidation.
510 */
511 spin_lock(&inode->i_lock);
512 if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
513 nfs_set_cache_invalid(inode,
514 NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
515 NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
516 NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
517 NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
518 NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
519 NFS_INO_INVALID_XATTR);
520 spin_unlock(&inode->i_lock);
521
522 list_add_tail_rcu(&delegation->super_list, &server->delegations);
523 rcu_assign_pointer(nfsi->delegation, delegation);
524 delegation = NULL;
525
526 atomic_long_inc(&nfs_active_delegations);
527
528 trace_nfs4_set_delegation(inode, type);
529
530 /* If we hold writebacks and have delegated mtime then update */
531 if (deleg_type == NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG &&
532 nfs_have_writebacks(inode))
533 nfs_update_delegated_mtime(inode);
534out:
535 spin_unlock(&clp->cl_lock);
536 if (delegation != NULL)
537 __nfs_free_delegation(delegation);
538 if (freeme != NULL) {
539 nfs_do_return_delegation(inode, freeme, 0);
540 nfs_free_delegation(freeme);
541 }
542 return status;
543}
544
545/*
546 * Basic procedure for returning a delegation to the server
547 */
548static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
549{
550 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
551 unsigned int mode = O_WRONLY | O_RDWR;
552 int err = 0;
553
554 if (delegation == NULL)
555 return 0;
556
557 if (!issync)
558 mode |= O_NONBLOCK;
559 /* Recall of any remaining application leases */
560 err = break_lease(inode, mode);
561
562 while (err == 0) {
563 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
564 break;
565 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
566 delegation->type);
567 if (!issync || err != -EAGAIN)
568 break;
569 /*
570 * Guard against state recovery
571 */
572 err = nfs4_wait_clnt_recover(clp);
573 }
574
575 if (err) {
576 nfs_abort_delegation_return(delegation, clp, err);
577 goto out;
578 }
579
580 err = nfs_do_return_delegation(inode, delegation, issync);
581out:
582 /* Refcount matched in nfs_start_delegation_return_locked() */
583 nfs_put_delegation(delegation);
584 return err;
585}
586
587static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
588{
589 bool ret = false;
590
591 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
592 ret = true;
593 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
594 struct inode *inode;
595
596 spin_lock(&delegation->lock);
597 inode = delegation->inode;
598 if (inode && list_empty(&NFS_I(inode)->open_files))
599 ret = true;
600 spin_unlock(&delegation->lock);
601 }
602 if (ret)
603 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
604 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
605 test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
606 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
607 ret = false;
608
609 return ret;
610}
611
612static int nfs_server_return_marked_delegations(struct nfs_server *server,
613 void __always_unused *data)
614{
615 struct nfs_delegation *delegation;
616 struct nfs_delegation *prev;
617 struct inode *inode;
618 struct inode *place_holder = NULL;
619 struct nfs_delegation *place_holder_deleg = NULL;
620 int err = 0;
621
622restart:
623 /*
624 * To avoid quadratic looping we hold a reference
625 * to an inode place_holder. Each time we restart, we
626 * list delegation in the server from the delegations
627 * of that inode.
628 * prev is an RCU-protected pointer to a delegation which
629 * wasn't marked for return and might be a good choice for
630 * the next place_holder.
631 */
632 prev = NULL;
633 delegation = NULL;
634 rcu_read_lock();
635 if (place_holder)
636 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
637 if (!delegation || delegation != place_holder_deleg)
638 delegation = list_entry_rcu(server->delegations.next,
639 struct nfs_delegation, super_list);
640 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
641 struct inode *to_put = NULL;
642
643 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
644 continue;
645 if (!nfs_delegation_need_return(delegation)) {
646 if (nfs4_is_valid_delegation(delegation, 0))
647 prev = delegation;
648 continue;
649 }
650 inode = nfs_delegation_grab_inode(delegation);
651 if (inode == NULL)
652 continue;
653
654 if (prev) {
655 struct inode *tmp = nfs_delegation_grab_inode(prev);
656 if (tmp) {
657 to_put = place_holder;
658 place_holder = tmp;
659 place_holder_deleg = prev;
660 }
661 }
662
663 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
664 rcu_read_unlock();
665
666 iput(to_put);
667
668 err = nfs_end_delegation_return(inode, delegation, 0);
669 iput(inode);
670 cond_resched();
671 if (!err)
672 goto restart;
673 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
674 goto out;
675 }
676 rcu_read_unlock();
677out:
678 iput(place_holder);
679 return err;
680}
681
682static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
683{
684 struct nfs_delegation *d;
685 bool ret = false;
686
687 list_for_each_entry_rcu (d, &server->delegations, super_list) {
688 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
689 continue;
690 nfs_mark_return_delegation(server, d);
691 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags);
692 ret = true;
693 }
694 return ret;
695}
696
697static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
698{
699 struct nfs_server *server;
700 bool ret = false;
701
702 if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))
703 goto out;
704 rcu_read_lock();
705 list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
706 if (nfs_server_clear_delayed_delegations(server))
707 ret = true;
708 }
709 rcu_read_unlock();
710out:
711 return ret;
712}
713
714/**
715 * nfs_client_return_marked_delegations - return previously marked delegations
716 * @clp: nfs_client to process
717 *
718 * Note that this function is designed to be called by the state
719 * manager thread. For this reason, it cannot flush the dirty data,
720 * since that could deadlock in case of a state recovery error.
721 *
722 * Returns zero on success, or a negative errno value.
723 */
724int nfs_client_return_marked_delegations(struct nfs_client *clp)
725{
726 int err = nfs_client_for_each_server(
727 clp, nfs_server_return_marked_delegations, NULL);
728 if (err)
729 return err;
730 /* If a return was delayed, sleep to prevent hard looping */
731 if (nfs_client_clear_delayed_delegations(clp))
732 ssleep(1);
733 return 0;
734}
735
736/**
737 * nfs_inode_evict_delegation - return delegation, don't reclaim opens
738 * @inode: inode to process
739 *
740 * Does not protect against delegation reclaims, therefore really only safe
741 * to be called from nfs4_clear_inode(). Guaranteed to always free
742 * the delegation structure.
743 */
744void nfs_inode_evict_delegation(struct inode *inode)
745{
746 struct nfs_delegation *delegation;
747
748 delegation = nfs_inode_detach_delegation(inode);
749 if (delegation != NULL) {
750 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
751 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
752 nfs_do_return_delegation(inode, delegation, 1);
753 nfs_free_delegation(delegation);
754 }
755}
756
757/**
758 * nfs4_inode_return_delegation - synchronously return a delegation
759 * @inode: inode to process
760 *
761 * This routine will always flush any dirty data to disk on the
762 * assumption that if we need to return the delegation, then
763 * we should stop caching.
764 *
765 * Returns zero on success, or a negative errno value.
766 */
767int nfs4_inode_return_delegation(struct inode *inode)
768{
769 struct nfs_inode *nfsi = NFS_I(inode);
770 struct nfs_delegation *delegation;
771
772 delegation = nfs_start_delegation_return(nfsi);
773 if (delegation != NULL) {
774 /* Synchronous recall of any application leases */
775 break_lease(inode, O_WRONLY | O_RDWR);
776 if (S_ISREG(inode->i_mode))
777 nfs_wb_all(inode);
778 return nfs_end_delegation_return(inode, delegation, 1);
779 }
780 return 0;
781}
782
783/**
784 * nfs4_inode_set_return_delegation_on_close - asynchronously return a delegation
785 * @inode: inode to process
786 *
787 * This routine is called to request that the delegation be returned as soon
788 * as the file is closed. If the file is already closed, the delegation is
789 * immediately returned.
790 */
791void nfs4_inode_set_return_delegation_on_close(struct inode *inode)
792{
793 struct nfs_delegation *delegation;
794 struct nfs_delegation *ret = NULL;
795
796 if (!inode)
797 return;
798 rcu_read_lock();
799 delegation = nfs4_get_valid_delegation(inode);
800 if (!delegation)
801 goto out;
802 spin_lock(&delegation->lock);
803 if (!delegation->inode)
804 goto out_unlock;
805 if (list_empty(&NFS_I(inode)->open_files) &&
806 !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
807 /* Refcount matched in nfs_end_delegation_return() */
808 ret = nfs_get_delegation(delegation);
809 } else
810 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
811out_unlock:
812 spin_unlock(&delegation->lock);
813 if (ret)
814 nfs_clear_verifier_delegated(inode);
815out:
816 rcu_read_unlock();
817 nfs_end_delegation_return(inode, ret, 0);
818}
819
820/**
821 * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
822 * @inode: inode to process
823 *
824 * This routine is called on file close in order to determine if the
825 * inode delegation needs to be returned immediately.
826 */
827void nfs4_inode_return_delegation_on_close(struct inode *inode)
828{
829 struct nfs_delegation *delegation;
830 struct nfs_delegation *ret = NULL;
831
832 if (!inode)
833 return;
834 rcu_read_lock();
835 delegation = nfs4_get_valid_delegation(inode);
836 if (!delegation)
837 goto out;
838 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
839 atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
840 spin_lock(&delegation->lock);
841 if (delegation->inode &&
842 list_empty(&NFS_I(inode)->open_files) &&
843 !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
844 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
845 /* Refcount matched in nfs_end_delegation_return() */
846 ret = nfs_get_delegation(delegation);
847 }
848 spin_unlock(&delegation->lock);
849 if (ret)
850 nfs_clear_verifier_delegated(inode);
851 }
852out:
853 rcu_read_unlock();
854 nfs_end_delegation_return(inode, ret, 0);
855}
856
857/**
858 * nfs4_inode_make_writeable
859 * @inode: pointer to inode
860 *
861 * Make the inode writeable by returning the delegation if necessary
862 *
863 * Returns zero on success, or a negative errno value.
864 */
865int nfs4_inode_make_writeable(struct inode *inode)
866{
867 struct nfs_delegation *delegation;
868
869 rcu_read_lock();
870 delegation = nfs4_get_valid_delegation(inode);
871 if (delegation == NULL ||
872 (nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
873 (delegation->type & FMODE_WRITE))) {
874 rcu_read_unlock();
875 return 0;
876 }
877 rcu_read_unlock();
878 return nfs4_inode_return_delegation(inode);
879}
880
881static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
882 struct nfs_delegation *delegation)
883{
884 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
885 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
886}
887
888static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
889{
890 struct nfs_delegation *delegation;
891 bool ret = false;
892
893 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
894 nfs_mark_return_delegation(server, delegation);
895 ret = true;
896 }
897 return ret;
898}
899
900static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
901{
902 struct nfs_server *server;
903
904 rcu_read_lock();
905 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
906 nfs_server_mark_return_all_delegations(server);
907 rcu_read_unlock();
908}
909
910static void nfs_delegation_run_state_manager(struct nfs_client *clp)
911{
912 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
913 nfs4_schedule_state_manager(clp);
914}
915
916/**
917 * nfs_expire_all_delegations
918 * @clp: client to process
919 *
920 */
921void nfs_expire_all_delegations(struct nfs_client *clp)
922{
923 nfs_client_mark_return_all_delegations(clp);
924 nfs_delegation_run_state_manager(clp);
925}
926
927/**
928 * nfs_server_return_all_delegations - return delegations for one superblock
929 * @server: pointer to nfs_server to process
930 *
931 */
932void nfs_server_return_all_delegations(struct nfs_server *server)
933{
934 struct nfs_client *clp = server->nfs_client;
935 bool need_wait;
936
937 if (clp == NULL)
938 return;
939
940 rcu_read_lock();
941 need_wait = nfs_server_mark_return_all_delegations(server);
942 rcu_read_unlock();
943
944 if (need_wait) {
945 nfs4_schedule_state_manager(clp);
946 nfs4_wait_clnt_recover(clp);
947 }
948}
949
950static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
951 fmode_t flags)
952{
953 struct nfs_delegation *delegation;
954
955 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
956 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
957 continue;
958 if (delegation->type & flags)
959 nfs_mark_return_if_closed_delegation(server, delegation);
960 }
961}
962
963static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
964 fmode_t flags)
965{
966 struct nfs_server *server;
967
968 rcu_read_lock();
969 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
970 nfs_mark_return_unused_delegation_types(server, flags);
971 rcu_read_unlock();
972}
973
974static void nfs_revoke_delegation(struct inode *inode,
975 const nfs4_stateid *stateid)
976{
977 struct nfs_delegation *delegation;
978 nfs4_stateid tmp;
979 bool ret = false;
980
981 rcu_read_lock();
982 delegation = rcu_dereference(NFS_I(inode)->delegation);
983 if (delegation == NULL)
984 goto out;
985 if (stateid == NULL) {
986 nfs4_stateid_copy(&tmp, &delegation->stateid);
987 stateid = &tmp;
988 } else {
989 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
990 goto out;
991 spin_lock(&delegation->lock);
992 if (stateid->seqid) {
993 if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
994 spin_unlock(&delegation->lock);
995 goto out;
996 }
997 delegation->stateid.seqid = stateid->seqid;
998 }
999 spin_unlock(&delegation->lock);
1000 }
1001 nfs_mark_delegation_revoked(delegation);
1002 ret = true;
1003out:
1004 rcu_read_unlock();
1005 if (ret)
1006 nfs_inode_find_state_and_recover(inode, stateid);
1007}
1008
1009void nfs_remove_bad_delegation(struct inode *inode,
1010 const nfs4_stateid *stateid)
1011{
1012 nfs_revoke_delegation(inode, stateid);
1013}
1014EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
1015
1016void nfs_delegation_mark_returned(struct inode *inode,
1017 const nfs4_stateid *stateid)
1018{
1019 struct nfs_delegation *delegation;
1020
1021 if (!inode)
1022 return;
1023
1024 rcu_read_lock();
1025 delegation = rcu_dereference(NFS_I(inode)->delegation);
1026 if (!delegation)
1027 goto out_rcu_unlock;
1028
1029 spin_lock(&delegation->lock);
1030 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
1031 goto out_spin_unlock;
1032 if (stateid->seqid) {
1033 /* If delegation->stateid is newer, dont mark as returned */
1034 if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
1035 goto out_clear_returning;
1036 if (delegation->stateid.seqid != stateid->seqid)
1037 delegation->stateid.seqid = stateid->seqid;
1038 }
1039
1040 nfs_mark_delegation_revoked(delegation);
1041 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
1042 spin_unlock(&delegation->lock);
1043 if (nfs_detach_delegation(NFS_I(inode), delegation, NFS_SERVER(inode)))
1044 nfs_put_delegation(delegation);
1045 goto out_rcu_unlock;
1046
1047out_clear_returning:
1048 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
1049out_spin_unlock:
1050 spin_unlock(&delegation->lock);
1051out_rcu_unlock:
1052 rcu_read_unlock();
1053
1054 nfs_inode_find_state_and_recover(inode, stateid);
1055}
1056
1057/**
1058 * nfs_expire_unused_delegation_types
1059 * @clp: client to process
1060 * @flags: delegation types to expire
1061 *
1062 */
1063void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1064{
1065 nfs_client_mark_return_unused_delegation_types(clp, flags);
1066 nfs_delegation_run_state_manager(clp);
1067}
1068
1069static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1070{
1071 struct nfs_delegation *delegation;
1072
1073 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1074 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
1075 continue;
1076 nfs_mark_return_if_closed_delegation(server, delegation);
1077 }
1078}
1079
1080/**
1081 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1082 * @clp: nfs_client to process
1083 *
1084 */
1085void nfs_expire_unreferenced_delegations(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_mark_return_unreferenced_delegations(server);
1092 rcu_read_unlock();
1093
1094 nfs_delegation_run_state_manager(clp);
1095}
1096
1097/**
1098 * nfs_async_inode_return_delegation - asynchronously return a delegation
1099 * @inode: inode to process
1100 * @stateid: state ID information
1101 *
1102 * Returns zero on success, or a negative errno value.
1103 */
1104int nfs_async_inode_return_delegation(struct inode *inode,
1105 const nfs4_stateid *stateid)
1106{
1107 struct nfs_server *server = NFS_SERVER(inode);
1108 struct nfs_client *clp = server->nfs_client;
1109 struct nfs_delegation *delegation;
1110
1111 rcu_read_lock();
1112 delegation = nfs4_get_valid_delegation(inode);
1113 if (delegation == NULL)
1114 goto out_enoent;
1115 if (stateid != NULL &&
1116 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1117 goto out_enoent;
1118 nfs_mark_return_delegation(server, delegation);
1119 rcu_read_unlock();
1120
1121 /* If there are any application leases or delegations, recall them */
1122 break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1123
1124 nfs_delegation_run_state_manager(clp);
1125 return 0;
1126out_enoent:
1127 rcu_read_unlock();
1128 return -ENOENT;
1129}
1130
1131static struct inode *
1132nfs_delegation_find_inode_server(struct nfs_server *server,
1133 const struct nfs_fh *fhandle)
1134{
1135 struct nfs_delegation *delegation;
1136 struct super_block *freeme = NULL;
1137 struct inode *res = NULL;
1138
1139 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1140 spin_lock(&delegation->lock);
1141 if (delegation->inode != NULL &&
1142 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1143 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1144 if (nfs_sb_active(server->super)) {
1145 freeme = server->super;
1146 res = igrab(delegation->inode);
1147 }
1148 spin_unlock(&delegation->lock);
1149 if (res != NULL)
1150 return res;
1151 if (freeme) {
1152 rcu_read_unlock();
1153 nfs_sb_deactive(freeme);
1154 rcu_read_lock();
1155 }
1156 return ERR_PTR(-EAGAIN);
1157 }
1158 spin_unlock(&delegation->lock);
1159 }
1160 return ERR_PTR(-ENOENT);
1161}
1162
1163/**
1164 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1165 * @clp: client state handle
1166 * @fhandle: filehandle from a delegation recall
1167 *
1168 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1169 * cannot be found.
1170 */
1171struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1172 const struct nfs_fh *fhandle)
1173{
1174 struct nfs_server *server;
1175 struct inode *res;
1176
1177 rcu_read_lock();
1178 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1179 res = nfs_delegation_find_inode_server(server, fhandle);
1180 if (res != ERR_PTR(-ENOENT)) {
1181 rcu_read_unlock();
1182 return res;
1183 }
1184 }
1185 rcu_read_unlock();
1186 return ERR_PTR(-ENOENT);
1187}
1188
1189static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1190{
1191 struct nfs_delegation *delegation;
1192
1193 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1194 /*
1195 * If the delegation may have been admin revoked, then we
1196 * cannot reclaim it.
1197 */
1198 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1199 continue;
1200 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1201 }
1202}
1203
1204/**
1205 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1206 * @clp: nfs_client to process
1207 *
1208 */
1209void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1210{
1211 struct nfs_server *server;
1212
1213 rcu_read_lock();
1214 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1215 nfs_delegation_mark_reclaim_server(server);
1216 rcu_read_unlock();
1217}
1218
1219static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1220 void __always_unused *data)
1221{
1222 struct nfs_delegation *delegation;
1223 struct inode *inode;
1224restart:
1225 rcu_read_lock();
1226 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1227 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1228 &delegation->flags) ||
1229 test_bit(NFS_DELEGATION_RETURNING,
1230 &delegation->flags) ||
1231 test_bit(NFS_DELEGATION_NEED_RECLAIM,
1232 &delegation->flags) == 0)
1233 continue;
1234 inode = nfs_delegation_grab_inode(delegation);
1235 if (inode == NULL)
1236 continue;
1237 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
1238 rcu_read_unlock();
1239 if (delegation != NULL) {
1240 if (nfs_detach_delegation(NFS_I(inode), delegation,
1241 server) != NULL)
1242 nfs_free_delegation(delegation);
1243 /* Match nfs_start_delegation_return_locked */
1244 nfs_put_delegation(delegation);
1245 }
1246 iput(inode);
1247 cond_resched();
1248 goto restart;
1249 }
1250 rcu_read_unlock();
1251 return 0;
1252}
1253
1254/**
1255 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1256 * @clp: nfs_client to process
1257 *
1258 */
1259void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1260{
1261 nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
1262 NULL);
1263}
1264
1265static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1266{
1267 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1268 BIT(NFS4CLNT_LEASE_EXPIRED) |
1269 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1270}
1271
1272static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1273 struct nfs_delegation *delegation)
1274{
1275 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1276 return;
1277 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1278 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1279 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1280}
1281
1282static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1283 struct inode *inode)
1284{
1285 struct nfs_delegation *delegation;
1286
1287 rcu_read_lock();
1288 delegation = rcu_dereference(NFS_I(inode)->delegation);
1289 if (delegation)
1290 nfs_mark_test_expired_delegation(server, delegation);
1291 rcu_read_unlock();
1292
1293}
1294
1295static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1296{
1297 struct nfs_delegation *delegation;
1298
1299 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1300 nfs_mark_test_expired_delegation(server, delegation);
1301}
1302
1303/**
1304 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1305 * @clp: nfs_client to process
1306 *
1307 * Iterates through all the delegations associated with this server and
1308 * marks them as needing to be checked for validity.
1309 */
1310void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1311{
1312 struct nfs_server *server;
1313
1314 rcu_read_lock();
1315 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1316 nfs_delegation_mark_test_expired_server(server);
1317 rcu_read_unlock();
1318}
1319
1320/**
1321 * nfs_test_expired_all_delegations - test all delegations for a client
1322 * @clp: nfs_client to process
1323 *
1324 * Helper for handling "recallable state revoked" status from server.
1325 */
1326void nfs_test_expired_all_delegations(struct nfs_client *clp)
1327{
1328 nfs_mark_test_expired_all_delegations(clp);
1329 nfs4_schedule_state_manager(clp);
1330}
1331
1332static void
1333nfs_delegation_test_free_expired(struct inode *inode,
1334 nfs4_stateid *stateid,
1335 const struct cred *cred)
1336{
1337 struct nfs_server *server = NFS_SERVER(inode);
1338 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1339 int status;
1340
1341 if (!cred)
1342 return;
1343 status = ops->test_and_free_expired(server, stateid, cred);
1344 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1345 nfs_remove_bad_delegation(inode, stateid);
1346}
1347
1348static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1349 void __always_unused *data)
1350{
1351 struct nfs_delegation *delegation;
1352 struct inode *inode;
1353 const struct cred *cred;
1354 nfs4_stateid stateid;
1355 unsigned long gen = ++server->delegation_gen;
1356
1357restart:
1358 rcu_read_lock();
1359 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1360 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1361 &delegation->flags) ||
1362 test_bit(NFS_DELEGATION_RETURNING,
1363 &delegation->flags) ||
1364 test_bit(NFS_DELEGATION_TEST_EXPIRED,
1365 &delegation->flags) == 0 ||
1366 delegation->test_gen == gen)
1367 continue;
1368 inode = nfs_delegation_grab_inode(delegation);
1369 if (inode == NULL)
1370 continue;
1371 spin_lock(&delegation->lock);
1372 cred = get_cred_rcu(delegation->cred);
1373 nfs4_stateid_copy(&stateid, &delegation->stateid);
1374 spin_unlock(&delegation->lock);
1375 delegation->test_gen = gen;
1376 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1377 rcu_read_unlock();
1378 nfs_delegation_test_free_expired(inode, &stateid, cred);
1379 put_cred(cred);
1380 if (!nfs4_server_rebooted(server->nfs_client)) {
1381 iput(inode);
1382 cond_resched();
1383 goto restart;
1384 }
1385 nfs_inode_mark_test_expired_delegation(server,inode);
1386 iput(inode);
1387 return -EAGAIN;
1388 }
1389 rcu_read_unlock();
1390 return 0;
1391}
1392
1393/**
1394 * nfs_reap_expired_delegations - reap expired delegations
1395 * @clp: nfs_client to process
1396 *
1397 * Iterates through all the delegations associated with this server and
1398 * checks if they have may have been revoked. This function is usually
1399 * expected to be called in cases where the server may have lost its
1400 * lease.
1401 */
1402void nfs_reap_expired_delegations(struct nfs_client *clp)
1403{
1404 nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
1405 NULL);
1406}
1407
1408void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1409 const nfs4_stateid *stateid)
1410{
1411 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1412 struct nfs_delegation *delegation;
1413 bool found = false;
1414
1415 rcu_read_lock();
1416 delegation = rcu_dereference(NFS_I(inode)->delegation);
1417 if (delegation &&
1418 nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
1419 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1420 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1421 found = true;
1422 }
1423 rcu_read_unlock();
1424 if (found)
1425 nfs4_schedule_state_manager(clp);
1426}
1427
1428/**
1429 * nfs_delegations_present - check for existence of delegations
1430 * @clp: client state handle
1431 *
1432 * Returns one if there are any nfs_delegation structures attached
1433 * to this nfs_client.
1434 */
1435int nfs_delegations_present(struct nfs_client *clp)
1436{
1437 struct nfs_server *server;
1438 int ret = 0;
1439
1440 rcu_read_lock();
1441 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1442 if (!list_empty(&server->delegations)) {
1443 ret = 1;
1444 break;
1445 }
1446 rcu_read_unlock();
1447 return ret;
1448}
1449
1450/**
1451 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1452 * @dst: stateid to refresh
1453 * @inode: inode to check
1454 *
1455 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1456 * that matches our delegation stateid. Otherwise "false" is returned.
1457 */
1458bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1459{
1460 struct nfs_delegation *delegation;
1461 bool ret = false;
1462 if (!inode)
1463 goto out;
1464
1465 rcu_read_lock();
1466 delegation = rcu_dereference(NFS_I(inode)->delegation);
1467 if (delegation != NULL &&
1468 nfs4_stateid_match_other(dst, &delegation->stateid) &&
1469 nfs4_stateid_is_newer(&delegation->stateid, dst) &&
1470 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1471 dst->seqid = delegation->stateid.seqid;
1472 ret = true;
1473 }
1474 rcu_read_unlock();
1475out:
1476 return ret;
1477}
1478
1479/**
1480 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1481 * @inode: inode to check
1482 * @flags: delegation type requirement
1483 * @dst: stateid data structure to fill in
1484 * @cred: optional argument to retrieve credential
1485 *
1486 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1487 * otherwise "false" is returned.
1488 */
1489bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1490 nfs4_stateid *dst, const struct cred **cred)
1491{
1492 struct nfs_inode *nfsi = NFS_I(inode);
1493 struct nfs_delegation *delegation;
1494 bool ret = false;
1495
1496 flags &= FMODE_READ|FMODE_WRITE;
1497 rcu_read_lock();
1498 delegation = rcu_dereference(nfsi->delegation);
1499 if (!delegation)
1500 goto out;
1501 spin_lock(&delegation->lock);
1502 ret = nfs4_is_valid_delegation(delegation, flags);
1503 if (ret) {
1504 nfs4_stateid_copy(dst, &delegation->stateid);
1505 nfs_mark_delegation_referenced(delegation);
1506 if (cred)
1507 *cred = get_cred(delegation->cred);
1508 }
1509 spin_unlock(&delegation->lock);
1510out:
1511 rcu_read_unlock();
1512 return ret;
1513}
1514
1515/**
1516 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1517 * @inode: inode to check
1518 *
1519 * This function checks the number of outstanding writes to the file
1520 * against the delegation 'space_limit' field to see if
1521 * the spec requires us to flush the file on close.
1522 */
1523bool nfs4_delegation_flush_on_close(const struct inode *inode)
1524{
1525 struct nfs_inode *nfsi = NFS_I(inode);
1526 struct nfs_delegation *delegation;
1527 bool ret = true;
1528
1529 rcu_read_lock();
1530 delegation = rcu_dereference(nfsi->delegation);
1531 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1532 goto out;
1533 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1534 ret = false;
1535out:
1536 rcu_read_unlock();
1537 return ret;
1538}
1539
1540module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);