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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
86nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
87 fmode_t flags)
88{
89 if (delegation != NULL && (delegation->type & flags) == flags &&
90 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
91 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
92 return true;
93 return false;
94}
95
96struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
97{
98 struct nfs_delegation *delegation;
99
100 delegation = rcu_dereference(NFS_I(inode)->delegation);
101 if (nfs4_is_valid_delegation(delegation, 0))
102 return delegation;
103 return NULL;
104}
105
106static int
107nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
108{
109 struct nfs_delegation *delegation;
110 int ret = 0;
111
112 flags &= FMODE_READ|FMODE_WRITE;
113 rcu_read_lock();
114 delegation = rcu_dereference(NFS_I(inode)->delegation);
115 if (nfs4_is_valid_delegation(delegation, flags)) {
116 if (mark)
117 nfs_mark_delegation_referenced(delegation);
118 ret = 1;
119 }
120 rcu_read_unlock();
121 return ret;
122}
123/**
124 * nfs4_have_delegation - check if inode has a delegation, mark it
125 * NFS_DELEGATION_REFERENCED if there is one.
126 * @inode: inode to check
127 * @flags: delegation types to check for
128 *
129 * Returns one if inode has the indicated delegation, otherwise zero.
130 */
131int nfs4_have_delegation(struct inode *inode, fmode_t flags)
132{
133 return nfs4_do_check_delegation(inode, flags, true);
134}
135
136/*
137 * nfs4_check_delegation - check if inode has a delegation, do not mark
138 * NFS_DELEGATION_REFERENCED if it has one.
139 */
140int nfs4_check_delegation(struct inode *inode, fmode_t flags)
141{
142 return nfs4_do_check_delegation(inode, flags, false);
143}
144
145static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
146{
147 struct inode *inode = state->inode;
148 struct file_lock *fl;
149 struct file_lock_context *flctx = locks_inode_context(inode);
150 struct list_head *list;
151 int status = 0;
152
153 if (flctx == NULL)
154 goto out;
155
156 list = &flctx->flc_posix;
157 spin_lock(&flctx->flc_lock);
158restart:
159 list_for_each_entry(fl, list, fl_list) {
160 if (nfs_file_open_context(fl->fl_file)->state != state)
161 continue;
162 spin_unlock(&flctx->flc_lock);
163 status = nfs4_lock_delegation_recall(fl, state, stateid);
164 if (status < 0)
165 goto out;
166 spin_lock(&flctx->flc_lock);
167 }
168 if (list == &flctx->flc_posix) {
169 list = &flctx->flc_flock;
170 goto restart;
171 }
172 spin_unlock(&flctx->flc_lock);
173out:
174 return status;
175}
176
177static int nfs_delegation_claim_opens(struct inode *inode,
178 const nfs4_stateid *stateid, fmode_t type)
179{
180 struct nfs_inode *nfsi = NFS_I(inode);
181 struct nfs_open_context *ctx;
182 struct nfs4_state_owner *sp;
183 struct nfs4_state *state;
184 unsigned int seq;
185 int err;
186
187again:
188 rcu_read_lock();
189 list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
190 state = ctx->state;
191 if (state == NULL)
192 continue;
193 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
194 continue;
195 if (!nfs4_valid_open_stateid(state))
196 continue;
197 if (!nfs4_stateid_match(&state->stateid, stateid))
198 continue;
199 if (!get_nfs_open_context(ctx))
200 continue;
201 rcu_read_unlock();
202 sp = state->owner;
203 /* Block nfs4_proc_unlck */
204 mutex_lock(&sp->so_delegreturn_mutex);
205 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
206 err = nfs4_open_delegation_recall(ctx, state, stateid);
207 if (!err)
208 err = nfs_delegation_claim_locks(state, stateid);
209 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
210 err = -EAGAIN;
211 mutex_unlock(&sp->so_delegreturn_mutex);
212 put_nfs_open_context(ctx);
213 if (err != 0)
214 return err;
215 goto again;
216 }
217 rcu_read_unlock();
218 return 0;
219}
220
221/**
222 * nfs_inode_reclaim_delegation - process a delegation reclaim request
223 * @inode: inode to process
224 * @cred: credential to use for request
225 * @type: delegation type
226 * @stateid: delegation stateid
227 * @pagemod_limit: write delegation "space_limit"
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)
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 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
247 if (test_and_clear_bit(NFS_DELEGATION_REVOKED,
248 &delegation->flags))
249 atomic_long_inc(&nfs_active_delegations);
250 spin_unlock(&delegation->lock);
251 rcu_read_unlock();
252 put_cred(oldcred);
253 trace_nfs4_reclaim_delegation(inode, type);
254 } else {
255 rcu_read_unlock();
256 nfs_inode_set_delegation(inode, cred, type, stateid,
257 pagemod_limit);
258 }
259}
260
261static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
262{
263 const struct cred *cred;
264 int res = 0;
265
266 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
267 spin_lock(&delegation->lock);
268 cred = get_cred(delegation->cred);
269 spin_unlock(&delegation->lock);
270 res = nfs4_proc_delegreturn(inode, cred,
271 &delegation->stateid,
272 issync);
273 put_cred(cred);
274 }
275 return res;
276}
277
278static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
279{
280 struct inode *inode = NULL;
281
282 spin_lock(&delegation->lock);
283 if (delegation->inode != NULL)
284 inode = igrab(delegation->inode);
285 if (!inode)
286 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
287 spin_unlock(&delegation->lock);
288 return inode;
289}
290
291static struct nfs_delegation *
292nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
293{
294 struct nfs_delegation *ret = NULL;
295 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
296
297 if (delegation == NULL)
298 goto out;
299 spin_lock(&delegation->lock);
300 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
301 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
302 /* Refcount matched in nfs_end_delegation_return() */
303 ret = nfs_get_delegation(delegation);
304 }
305 spin_unlock(&delegation->lock);
306 if (ret)
307 nfs_clear_verifier_delegated(&nfsi->vfs_inode);
308out:
309 return ret;
310}
311
312static struct nfs_delegation *
313nfs_start_delegation_return(struct nfs_inode *nfsi)
314{
315 struct nfs_delegation *delegation;
316
317 rcu_read_lock();
318 delegation = nfs_start_delegation_return_locked(nfsi);
319 rcu_read_unlock();
320 return delegation;
321}
322
323static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
324 struct nfs_client *clp, int err)
325{
326
327 spin_lock(&delegation->lock);
328 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
329 if (err == -EAGAIN) {
330 set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
331 set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state);
332 }
333 spin_unlock(&delegation->lock);
334}
335
336static struct nfs_delegation *
337nfs_detach_delegation_locked(struct nfs_inode *nfsi,
338 struct nfs_delegation *delegation,
339 struct nfs_client *clp)
340{
341 struct nfs_delegation *deleg_cur =
342 rcu_dereference_protected(nfsi->delegation,
343 lockdep_is_held(&clp->cl_lock));
344
345 if (deleg_cur == NULL || delegation != deleg_cur)
346 return NULL;
347
348 spin_lock(&delegation->lock);
349 if (!delegation->inode) {
350 spin_unlock(&delegation->lock);
351 return NULL;
352 }
353 list_del_rcu(&delegation->super_list);
354 delegation->inode = NULL;
355 rcu_assign_pointer(nfsi->delegation, NULL);
356 spin_unlock(&delegation->lock);
357 return delegation;
358}
359
360static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
361 struct nfs_delegation *delegation,
362 struct nfs_server *server)
363{
364 struct nfs_client *clp = server->nfs_client;
365
366 spin_lock(&clp->cl_lock);
367 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
368 spin_unlock(&clp->cl_lock);
369 return delegation;
370}
371
372static struct nfs_delegation *
373nfs_inode_detach_delegation(struct inode *inode)
374{
375 struct nfs_inode *nfsi = NFS_I(inode);
376 struct nfs_server *server = NFS_SERVER(inode);
377 struct nfs_delegation *delegation;
378
379 rcu_read_lock();
380 delegation = rcu_dereference(nfsi->delegation);
381 if (delegation != NULL)
382 delegation = nfs_detach_delegation(nfsi, delegation, server);
383 rcu_read_unlock();
384 return delegation;
385}
386
387static void
388nfs_update_delegation_cred(struct nfs_delegation *delegation,
389 const struct cred *cred)
390{
391 const struct cred *old;
392
393 if (cred_fscmp(delegation->cred, cred) != 0) {
394 old = xchg(&delegation->cred, get_cred(cred));
395 put_cred(old);
396 }
397}
398
399static void
400nfs_update_inplace_delegation(struct nfs_delegation *delegation,
401 const struct nfs_delegation *update)
402{
403 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
404 delegation->stateid.seqid = update->stateid.seqid;
405 smp_wmb();
406 delegation->type = update->type;
407 delegation->pagemod_limit = update->pagemod_limit;
408 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
409 delegation->change_attr = update->change_attr;
410 nfs_update_delegation_cred(delegation, update->cred);
411 /* smp_mb__before_atomic() is implicit due to xchg() */
412 clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
413 atomic_long_inc(&nfs_active_delegations);
414 }
415 }
416}
417
418/**
419 * nfs_inode_set_delegation - set up a delegation on an inode
420 * @inode: inode to which delegation applies
421 * @cred: cred to use for subsequent delegation processing
422 * @type: delegation type
423 * @stateid: delegation stateid
424 * @pagemod_limit: write delegation "space_limit"
425 *
426 * Returns zero on success, or a negative errno value.
427 */
428int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
429 fmode_t type,
430 const nfs4_stateid *stateid,
431 unsigned long pagemod_limit)
432{
433 struct nfs_server *server = NFS_SERVER(inode);
434 struct nfs_client *clp = server->nfs_client;
435 struct nfs_inode *nfsi = NFS_I(inode);
436 struct nfs_delegation *delegation, *old_delegation;
437 struct nfs_delegation *freeme = NULL;
438 int status = 0;
439
440 delegation = kmalloc(sizeof(*delegation), GFP_KERNEL_ACCOUNT);
441 if (delegation == NULL)
442 return -ENOMEM;
443 nfs4_stateid_copy(&delegation->stateid, stateid);
444 refcount_set(&delegation->refcount, 1);
445 delegation->type = type;
446 delegation->pagemod_limit = pagemod_limit;
447 delegation->change_attr = inode_peek_iversion_raw(inode);
448 delegation->cred = get_cred(cred);
449 delegation->inode = inode;
450 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
451 spin_lock_init(&delegation->lock);
452
453 spin_lock(&clp->cl_lock);
454 old_delegation = rcu_dereference_protected(nfsi->delegation,
455 lockdep_is_held(&clp->cl_lock));
456 if (old_delegation == NULL)
457 goto add_new;
458 /* Is this an update of the existing delegation? */
459 if (nfs4_stateid_match_other(&old_delegation->stateid,
460 &delegation->stateid)) {
461 spin_lock(&old_delegation->lock);
462 nfs_update_inplace_delegation(old_delegation,
463 delegation);
464 spin_unlock(&old_delegation->lock);
465 goto out;
466 }
467 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
468 /*
469 * Deal with broken servers that hand out two
470 * delegations for the same file.
471 * Allow for upgrades to a WRITE delegation, but
472 * nothing else.
473 */
474 dfprintk(FILE, "%s: server %s handed out "
475 "a duplicate delegation!\n",
476 __func__, clp->cl_hostname);
477 if (delegation->type == old_delegation->type ||
478 !(delegation->type & FMODE_WRITE)) {
479 freeme = delegation;
480 delegation = NULL;
481 goto out;
482 }
483 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
484 &old_delegation->flags))
485 goto out;
486 }
487 freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
488 if (freeme == NULL)
489 goto out;
490add_new:
491 /*
492 * If we didn't revalidate the change attribute before setting
493 * the delegation, then pre-emptively ask for a full attribute
494 * cache revalidation.
495 */
496 spin_lock(&inode->i_lock);
497 if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
498 nfs_set_cache_invalid(inode,
499 NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
500 NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
501 NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
502 NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
503 NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
504 NFS_INO_INVALID_XATTR);
505 spin_unlock(&inode->i_lock);
506
507 list_add_tail_rcu(&delegation->super_list, &server->delegations);
508 rcu_assign_pointer(nfsi->delegation, delegation);
509 delegation = NULL;
510
511 atomic_long_inc(&nfs_active_delegations);
512
513 trace_nfs4_set_delegation(inode, type);
514out:
515 spin_unlock(&clp->cl_lock);
516 if (delegation != NULL)
517 __nfs_free_delegation(delegation);
518 if (freeme != NULL) {
519 nfs_do_return_delegation(inode, freeme, 0);
520 nfs_free_delegation(freeme);
521 }
522 return status;
523}
524
525/*
526 * Basic procedure for returning a delegation to the server
527 */
528static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
529{
530 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
531 unsigned int mode = O_WRONLY | O_RDWR;
532 int err = 0;
533
534 if (delegation == NULL)
535 return 0;
536
537 if (!issync)
538 mode |= O_NONBLOCK;
539 /* Recall of any remaining application leases */
540 err = break_lease(inode, mode);
541
542 while (err == 0) {
543 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
544 break;
545 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
546 delegation->type);
547 if (!issync || err != -EAGAIN)
548 break;
549 /*
550 * Guard against state recovery
551 */
552 err = nfs4_wait_clnt_recover(clp);
553 }
554
555 if (err) {
556 nfs_abort_delegation_return(delegation, clp, err);
557 goto out;
558 }
559
560 err = nfs_do_return_delegation(inode, delegation, issync);
561out:
562 /* Refcount matched in nfs_start_delegation_return_locked() */
563 nfs_put_delegation(delegation);
564 return err;
565}
566
567static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
568{
569 bool ret = false;
570
571 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
572 ret = true;
573 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
574 struct inode *inode;
575
576 spin_lock(&delegation->lock);
577 inode = delegation->inode;
578 if (inode && list_empty(&NFS_I(inode)->open_files))
579 ret = true;
580 spin_unlock(&delegation->lock);
581 }
582 if (ret)
583 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
584 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
585 test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
586 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
587 ret = false;
588
589 return ret;
590}
591
592static int nfs_server_return_marked_delegations(struct nfs_server *server,
593 void __always_unused *data)
594{
595 struct nfs_delegation *delegation;
596 struct nfs_delegation *prev;
597 struct inode *inode;
598 struct inode *place_holder = NULL;
599 struct nfs_delegation *place_holder_deleg = NULL;
600 int err = 0;
601
602restart:
603 /*
604 * To avoid quadratic looping we hold a reference
605 * to an inode place_holder. Each time we restart, we
606 * list delegation in the server from the delegations
607 * of that inode.
608 * prev is an RCU-protected pointer to a delegation which
609 * wasn't marked for return and might be a good choice for
610 * the next place_holder.
611 */
612 prev = NULL;
613 delegation = NULL;
614 rcu_read_lock();
615 if (place_holder)
616 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
617 if (!delegation || delegation != place_holder_deleg)
618 delegation = list_entry_rcu(server->delegations.next,
619 struct nfs_delegation, super_list);
620 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
621 struct inode *to_put = NULL;
622
623 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
624 continue;
625 if (!nfs_delegation_need_return(delegation)) {
626 if (nfs4_is_valid_delegation(delegation, 0))
627 prev = delegation;
628 continue;
629 }
630
631 if (prev) {
632 struct inode *tmp = nfs_delegation_grab_inode(prev);
633 if (tmp) {
634 to_put = place_holder;
635 place_holder = tmp;
636 place_holder_deleg = prev;
637 }
638 }
639
640 inode = nfs_delegation_grab_inode(delegation);
641 if (inode == NULL) {
642 rcu_read_unlock();
643 iput(to_put);
644 goto restart;
645 }
646 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
647 rcu_read_unlock();
648
649 iput(to_put);
650
651 err = nfs_end_delegation_return(inode, delegation, 0);
652 iput(inode);
653 cond_resched();
654 if (!err)
655 goto restart;
656 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
657 goto out;
658 }
659 rcu_read_unlock();
660out:
661 iput(place_holder);
662 return err;
663}
664
665static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
666{
667 struct nfs_delegation *d;
668 bool ret = false;
669
670 list_for_each_entry_rcu (d, &server->delegations, super_list) {
671 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
672 continue;
673 nfs_mark_return_delegation(server, d);
674 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags);
675 ret = true;
676 }
677 return ret;
678}
679
680static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
681{
682 struct nfs_server *server;
683 bool ret = false;
684
685 if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))
686 goto out;
687 rcu_read_lock();
688 list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
689 if (nfs_server_clear_delayed_delegations(server))
690 ret = true;
691 }
692 rcu_read_unlock();
693out:
694 return ret;
695}
696
697/**
698 * nfs_client_return_marked_delegations - return previously marked delegations
699 * @clp: nfs_client to process
700 *
701 * Note that this function is designed to be called by the state
702 * manager thread. For this reason, it cannot flush the dirty data,
703 * since that could deadlock in case of a state recovery error.
704 *
705 * Returns zero on success, or a negative errno value.
706 */
707int nfs_client_return_marked_delegations(struct nfs_client *clp)
708{
709 int err = nfs_client_for_each_server(
710 clp, nfs_server_return_marked_delegations, NULL);
711 if (err)
712 return err;
713 /* If a return was delayed, sleep to prevent hard looping */
714 if (nfs_client_clear_delayed_delegations(clp))
715 ssleep(1);
716 return 0;
717}
718
719/**
720 * nfs_inode_evict_delegation - return delegation, don't reclaim opens
721 * @inode: inode to process
722 *
723 * Does not protect against delegation reclaims, therefore really only safe
724 * to be called from nfs4_clear_inode(). Guaranteed to always free
725 * the delegation structure.
726 */
727void nfs_inode_evict_delegation(struct inode *inode)
728{
729 struct nfs_delegation *delegation;
730
731 delegation = nfs_inode_detach_delegation(inode);
732 if (delegation != NULL) {
733 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
734 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
735 nfs_do_return_delegation(inode, delegation, 1);
736 nfs_free_delegation(delegation);
737 }
738}
739
740/**
741 * nfs4_inode_return_delegation - synchronously return a delegation
742 * @inode: inode to process
743 *
744 * This routine will always flush any dirty data to disk on the
745 * assumption that if we need to return the delegation, then
746 * we should stop caching.
747 *
748 * Returns zero on success, or a negative errno value.
749 */
750int nfs4_inode_return_delegation(struct inode *inode)
751{
752 struct nfs_inode *nfsi = NFS_I(inode);
753 struct nfs_delegation *delegation;
754
755 delegation = nfs_start_delegation_return(nfsi);
756 if (delegation != NULL) {
757 /* Synchronous recall of any application leases */
758 break_lease(inode, O_WRONLY | O_RDWR);
759 if (S_ISREG(inode->i_mode))
760 nfs_wb_all(inode);
761 return nfs_end_delegation_return(inode, delegation, 1);
762 }
763 return 0;
764}
765
766/**
767 * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
768 * @inode: inode to process
769 *
770 * This routine is called on file close in order to determine if the
771 * inode delegation needs to be returned immediately.
772 */
773void nfs4_inode_return_delegation_on_close(struct inode *inode)
774{
775 struct nfs_delegation *delegation;
776 struct nfs_delegation *ret = NULL;
777
778 if (!inode)
779 return;
780 rcu_read_lock();
781 delegation = nfs4_get_valid_delegation(inode);
782 if (!delegation)
783 goto out;
784 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
785 atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
786 spin_lock(&delegation->lock);
787 if (delegation->inode &&
788 list_empty(&NFS_I(inode)->open_files) &&
789 !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
790 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
791 /* Refcount matched in nfs_end_delegation_return() */
792 ret = nfs_get_delegation(delegation);
793 }
794 spin_unlock(&delegation->lock);
795 if (ret)
796 nfs_clear_verifier_delegated(inode);
797 }
798out:
799 rcu_read_unlock();
800 nfs_end_delegation_return(inode, ret, 0);
801}
802
803/**
804 * nfs4_inode_make_writeable
805 * @inode: pointer to inode
806 *
807 * Make the inode writeable by returning the delegation if necessary
808 *
809 * Returns zero on success, or a negative errno value.
810 */
811int nfs4_inode_make_writeable(struct inode *inode)
812{
813 struct nfs_delegation *delegation;
814
815 rcu_read_lock();
816 delegation = nfs4_get_valid_delegation(inode);
817 if (delegation == NULL ||
818 (nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
819 (delegation->type & FMODE_WRITE))) {
820 rcu_read_unlock();
821 return 0;
822 }
823 rcu_read_unlock();
824 return nfs4_inode_return_delegation(inode);
825}
826
827static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
828 struct nfs_delegation *delegation)
829{
830 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
831 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
832}
833
834static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
835{
836 struct nfs_delegation *delegation;
837 bool ret = false;
838
839 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
840 nfs_mark_return_delegation(server, delegation);
841 ret = true;
842 }
843 return ret;
844}
845
846static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
847{
848 struct nfs_server *server;
849
850 rcu_read_lock();
851 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
852 nfs_server_mark_return_all_delegations(server);
853 rcu_read_unlock();
854}
855
856static void nfs_delegation_run_state_manager(struct nfs_client *clp)
857{
858 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
859 nfs4_schedule_state_manager(clp);
860}
861
862/**
863 * nfs_expire_all_delegations
864 * @clp: client to process
865 *
866 */
867void nfs_expire_all_delegations(struct nfs_client *clp)
868{
869 nfs_client_mark_return_all_delegations(clp);
870 nfs_delegation_run_state_manager(clp);
871}
872
873/**
874 * nfs_server_return_all_delegations - return delegations for one superblock
875 * @server: pointer to nfs_server to process
876 *
877 */
878void nfs_server_return_all_delegations(struct nfs_server *server)
879{
880 struct nfs_client *clp = server->nfs_client;
881 bool need_wait;
882
883 if (clp == NULL)
884 return;
885
886 rcu_read_lock();
887 need_wait = nfs_server_mark_return_all_delegations(server);
888 rcu_read_unlock();
889
890 if (need_wait) {
891 nfs4_schedule_state_manager(clp);
892 nfs4_wait_clnt_recover(clp);
893 }
894}
895
896static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
897 fmode_t flags)
898{
899 struct nfs_delegation *delegation;
900
901 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
902 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
903 continue;
904 if (delegation->type & flags)
905 nfs_mark_return_if_closed_delegation(server, delegation);
906 }
907}
908
909static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
910 fmode_t flags)
911{
912 struct nfs_server *server;
913
914 rcu_read_lock();
915 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
916 nfs_mark_return_unused_delegation_types(server, flags);
917 rcu_read_unlock();
918}
919
920static void nfs_revoke_delegation(struct inode *inode,
921 const nfs4_stateid *stateid)
922{
923 struct nfs_delegation *delegation;
924 nfs4_stateid tmp;
925 bool ret = false;
926
927 rcu_read_lock();
928 delegation = rcu_dereference(NFS_I(inode)->delegation);
929 if (delegation == NULL)
930 goto out;
931 if (stateid == NULL) {
932 nfs4_stateid_copy(&tmp, &delegation->stateid);
933 stateid = &tmp;
934 } else {
935 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
936 goto out;
937 spin_lock(&delegation->lock);
938 if (stateid->seqid) {
939 if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
940 spin_unlock(&delegation->lock);
941 goto out;
942 }
943 delegation->stateid.seqid = stateid->seqid;
944 }
945 spin_unlock(&delegation->lock);
946 }
947 nfs_mark_delegation_revoked(delegation);
948 ret = true;
949out:
950 rcu_read_unlock();
951 if (ret)
952 nfs_inode_find_state_and_recover(inode, stateid);
953}
954
955void nfs_remove_bad_delegation(struct inode *inode,
956 const nfs4_stateid *stateid)
957{
958 nfs_revoke_delegation(inode, stateid);
959}
960EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
961
962void nfs_delegation_mark_returned(struct inode *inode,
963 const nfs4_stateid *stateid)
964{
965 struct nfs_delegation *delegation;
966
967 if (!inode)
968 return;
969
970 rcu_read_lock();
971 delegation = rcu_dereference(NFS_I(inode)->delegation);
972 if (!delegation)
973 goto out_rcu_unlock;
974
975 spin_lock(&delegation->lock);
976 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
977 goto out_spin_unlock;
978 if (stateid->seqid) {
979 /* If delegation->stateid is newer, dont mark as returned */
980 if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
981 goto out_clear_returning;
982 if (delegation->stateid.seqid != stateid->seqid)
983 delegation->stateid.seqid = stateid->seqid;
984 }
985
986 nfs_mark_delegation_revoked(delegation);
987
988out_clear_returning:
989 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
990out_spin_unlock:
991 spin_unlock(&delegation->lock);
992out_rcu_unlock:
993 rcu_read_unlock();
994
995 nfs_inode_find_state_and_recover(inode, stateid);
996}
997
998/**
999 * nfs_expire_unused_delegation_types
1000 * @clp: client to process
1001 * @flags: delegation types to expire
1002 *
1003 */
1004void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1005{
1006 nfs_client_mark_return_unused_delegation_types(clp, flags);
1007 nfs_delegation_run_state_manager(clp);
1008}
1009
1010static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1011{
1012 struct nfs_delegation *delegation;
1013
1014 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1015 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
1016 continue;
1017 nfs_mark_return_if_closed_delegation(server, delegation);
1018 }
1019}
1020
1021/**
1022 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1023 * @clp: nfs_client to process
1024 *
1025 */
1026void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
1027{
1028 struct nfs_server *server;
1029
1030 rcu_read_lock();
1031 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1032 nfs_mark_return_unreferenced_delegations(server);
1033 rcu_read_unlock();
1034
1035 nfs_delegation_run_state_manager(clp);
1036}
1037
1038/**
1039 * nfs_async_inode_return_delegation - asynchronously return a delegation
1040 * @inode: inode to process
1041 * @stateid: state ID information
1042 *
1043 * Returns zero on success, or a negative errno value.
1044 */
1045int nfs_async_inode_return_delegation(struct inode *inode,
1046 const nfs4_stateid *stateid)
1047{
1048 struct nfs_server *server = NFS_SERVER(inode);
1049 struct nfs_client *clp = server->nfs_client;
1050 struct nfs_delegation *delegation;
1051
1052 rcu_read_lock();
1053 delegation = nfs4_get_valid_delegation(inode);
1054 if (delegation == NULL)
1055 goto out_enoent;
1056 if (stateid != NULL &&
1057 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1058 goto out_enoent;
1059 nfs_mark_return_delegation(server, delegation);
1060 rcu_read_unlock();
1061
1062 /* If there are any application leases or delegations, recall them */
1063 break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1064
1065 nfs_delegation_run_state_manager(clp);
1066 return 0;
1067out_enoent:
1068 rcu_read_unlock();
1069 return -ENOENT;
1070}
1071
1072static struct inode *
1073nfs_delegation_find_inode_server(struct nfs_server *server,
1074 const struct nfs_fh *fhandle)
1075{
1076 struct nfs_delegation *delegation;
1077 struct super_block *freeme = NULL;
1078 struct inode *res = NULL;
1079
1080 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1081 spin_lock(&delegation->lock);
1082 if (delegation->inode != NULL &&
1083 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1084 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1085 if (nfs_sb_active(server->super)) {
1086 freeme = server->super;
1087 res = igrab(delegation->inode);
1088 }
1089 spin_unlock(&delegation->lock);
1090 if (res != NULL)
1091 return res;
1092 if (freeme) {
1093 rcu_read_unlock();
1094 nfs_sb_deactive(freeme);
1095 rcu_read_lock();
1096 }
1097 return ERR_PTR(-EAGAIN);
1098 }
1099 spin_unlock(&delegation->lock);
1100 }
1101 return ERR_PTR(-ENOENT);
1102}
1103
1104/**
1105 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1106 * @clp: client state handle
1107 * @fhandle: filehandle from a delegation recall
1108 *
1109 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1110 * cannot be found.
1111 */
1112struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1113 const struct nfs_fh *fhandle)
1114{
1115 struct nfs_server *server;
1116 struct inode *res;
1117
1118 rcu_read_lock();
1119 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1120 res = nfs_delegation_find_inode_server(server, fhandle);
1121 if (res != ERR_PTR(-ENOENT)) {
1122 rcu_read_unlock();
1123 return res;
1124 }
1125 }
1126 rcu_read_unlock();
1127 return ERR_PTR(-ENOENT);
1128}
1129
1130static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1131{
1132 struct nfs_delegation *delegation;
1133
1134 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1135 /*
1136 * If the delegation may have been admin revoked, then we
1137 * cannot reclaim it.
1138 */
1139 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1140 continue;
1141 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1142 }
1143}
1144
1145/**
1146 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1147 * @clp: nfs_client to process
1148 *
1149 */
1150void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1151{
1152 struct nfs_server *server;
1153
1154 rcu_read_lock();
1155 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1156 nfs_delegation_mark_reclaim_server(server);
1157 rcu_read_unlock();
1158}
1159
1160static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1161 void __always_unused *data)
1162{
1163 struct nfs_delegation *delegation;
1164 struct inode *inode;
1165restart:
1166 rcu_read_lock();
1167restart_locked:
1168 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1169 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1170 &delegation->flags) ||
1171 test_bit(NFS_DELEGATION_RETURNING,
1172 &delegation->flags) ||
1173 test_bit(NFS_DELEGATION_NEED_RECLAIM,
1174 &delegation->flags) == 0)
1175 continue;
1176 inode = nfs_delegation_grab_inode(delegation);
1177 if (inode == NULL)
1178 goto restart_locked;
1179 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
1180 rcu_read_unlock();
1181 if (delegation != NULL) {
1182 if (nfs_detach_delegation(NFS_I(inode), delegation,
1183 server) != NULL)
1184 nfs_free_delegation(delegation);
1185 /* Match nfs_start_delegation_return_locked */
1186 nfs_put_delegation(delegation);
1187 }
1188 iput(inode);
1189 cond_resched();
1190 goto restart;
1191 }
1192 rcu_read_unlock();
1193 return 0;
1194}
1195
1196/**
1197 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1198 * @clp: nfs_client to process
1199 *
1200 */
1201void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1202{
1203 nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
1204 NULL);
1205}
1206
1207static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1208{
1209 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1210 BIT(NFS4CLNT_LEASE_EXPIRED) |
1211 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1212}
1213
1214static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1215 struct nfs_delegation *delegation)
1216{
1217 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1218 return;
1219 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1220 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1221 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1222}
1223
1224static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1225 struct inode *inode)
1226{
1227 struct nfs_delegation *delegation;
1228
1229 rcu_read_lock();
1230 delegation = rcu_dereference(NFS_I(inode)->delegation);
1231 if (delegation)
1232 nfs_mark_test_expired_delegation(server, delegation);
1233 rcu_read_unlock();
1234
1235}
1236
1237static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1238{
1239 struct nfs_delegation *delegation;
1240
1241 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1242 nfs_mark_test_expired_delegation(server, delegation);
1243}
1244
1245/**
1246 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1247 * @clp: nfs_client to process
1248 *
1249 * Iterates through all the delegations associated with this server and
1250 * marks them as needing to be checked for validity.
1251 */
1252void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1253{
1254 struct nfs_server *server;
1255
1256 rcu_read_lock();
1257 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1258 nfs_delegation_mark_test_expired_server(server);
1259 rcu_read_unlock();
1260}
1261
1262/**
1263 * nfs_test_expired_all_delegations - test all delegations for a client
1264 * @clp: nfs_client to process
1265 *
1266 * Helper for handling "recallable state revoked" status from server.
1267 */
1268void nfs_test_expired_all_delegations(struct nfs_client *clp)
1269{
1270 nfs_mark_test_expired_all_delegations(clp);
1271 nfs4_schedule_state_manager(clp);
1272}
1273
1274static void
1275nfs_delegation_test_free_expired(struct inode *inode,
1276 nfs4_stateid *stateid,
1277 const struct cred *cred)
1278{
1279 struct nfs_server *server = NFS_SERVER(inode);
1280 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1281 int status;
1282
1283 if (!cred)
1284 return;
1285 status = ops->test_and_free_expired(server, stateid, cred);
1286 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1287 nfs_remove_bad_delegation(inode, stateid);
1288}
1289
1290static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1291 void __always_unused *data)
1292{
1293 struct nfs_delegation *delegation;
1294 struct inode *inode;
1295 const struct cred *cred;
1296 nfs4_stateid stateid;
1297restart:
1298 rcu_read_lock();
1299restart_locked:
1300 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1301 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1302 &delegation->flags) ||
1303 test_bit(NFS_DELEGATION_RETURNING,
1304 &delegation->flags) ||
1305 test_bit(NFS_DELEGATION_TEST_EXPIRED,
1306 &delegation->flags) == 0)
1307 continue;
1308 inode = nfs_delegation_grab_inode(delegation);
1309 if (inode == NULL)
1310 goto restart_locked;
1311 spin_lock(&delegation->lock);
1312 cred = get_cred_rcu(delegation->cred);
1313 nfs4_stateid_copy(&stateid, &delegation->stateid);
1314 spin_unlock(&delegation->lock);
1315 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1316 rcu_read_unlock();
1317 nfs_delegation_test_free_expired(inode, &stateid, cred);
1318 put_cred(cred);
1319 if (!nfs4_server_rebooted(server->nfs_client)) {
1320 iput(inode);
1321 cond_resched();
1322 goto restart;
1323 }
1324 nfs_inode_mark_test_expired_delegation(server,inode);
1325 iput(inode);
1326 return -EAGAIN;
1327 }
1328 rcu_read_unlock();
1329 return 0;
1330}
1331
1332/**
1333 * nfs_reap_expired_delegations - reap expired delegations
1334 * @clp: nfs_client to process
1335 *
1336 * Iterates through all the delegations associated with this server and
1337 * checks if they have may have been revoked. This function is usually
1338 * expected to be called in cases where the server may have lost its
1339 * lease.
1340 */
1341void nfs_reap_expired_delegations(struct nfs_client *clp)
1342{
1343 nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
1344 NULL);
1345}
1346
1347void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1348 const nfs4_stateid *stateid)
1349{
1350 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1351 struct nfs_delegation *delegation;
1352 bool found = false;
1353
1354 rcu_read_lock();
1355 delegation = rcu_dereference(NFS_I(inode)->delegation);
1356 if (delegation &&
1357 nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
1358 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1359 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1360 found = true;
1361 }
1362 rcu_read_unlock();
1363 if (found)
1364 nfs4_schedule_state_manager(clp);
1365}
1366
1367/**
1368 * nfs_delegations_present - check for existence of delegations
1369 * @clp: client state handle
1370 *
1371 * Returns one if there are any nfs_delegation structures attached
1372 * to this nfs_client.
1373 */
1374int nfs_delegations_present(struct nfs_client *clp)
1375{
1376 struct nfs_server *server;
1377 int ret = 0;
1378
1379 rcu_read_lock();
1380 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1381 if (!list_empty(&server->delegations)) {
1382 ret = 1;
1383 break;
1384 }
1385 rcu_read_unlock();
1386 return ret;
1387}
1388
1389/**
1390 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1391 * @dst: stateid to refresh
1392 * @inode: inode to check
1393 *
1394 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1395 * that matches our delegation stateid. Otherwise "false" is returned.
1396 */
1397bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1398{
1399 struct nfs_delegation *delegation;
1400 bool ret = false;
1401 if (!inode)
1402 goto out;
1403
1404 rcu_read_lock();
1405 delegation = rcu_dereference(NFS_I(inode)->delegation);
1406 if (delegation != NULL &&
1407 nfs4_stateid_match_other(dst, &delegation->stateid) &&
1408 nfs4_stateid_is_newer(&delegation->stateid, dst) &&
1409 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1410 dst->seqid = delegation->stateid.seqid;
1411 ret = true;
1412 }
1413 rcu_read_unlock();
1414out:
1415 return ret;
1416}
1417
1418/**
1419 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1420 * @inode: inode to check
1421 * @flags: delegation type requirement
1422 * @dst: stateid data structure to fill in
1423 * @cred: optional argument to retrieve credential
1424 *
1425 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1426 * otherwise "false" is returned.
1427 */
1428bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1429 nfs4_stateid *dst, const struct cred **cred)
1430{
1431 struct nfs_inode *nfsi = NFS_I(inode);
1432 struct nfs_delegation *delegation;
1433 bool ret = false;
1434
1435 flags &= FMODE_READ|FMODE_WRITE;
1436 rcu_read_lock();
1437 delegation = rcu_dereference(nfsi->delegation);
1438 if (!delegation)
1439 goto out;
1440 spin_lock(&delegation->lock);
1441 ret = nfs4_is_valid_delegation(delegation, flags);
1442 if (ret) {
1443 nfs4_stateid_copy(dst, &delegation->stateid);
1444 nfs_mark_delegation_referenced(delegation);
1445 if (cred)
1446 *cred = get_cred(delegation->cred);
1447 }
1448 spin_unlock(&delegation->lock);
1449out:
1450 rcu_read_unlock();
1451 return ret;
1452}
1453
1454/**
1455 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1456 * @inode: inode to check
1457 *
1458 * This function checks the number of outstanding writes to the file
1459 * against the delegation 'space_limit' field to see if
1460 * the spec requires us to flush the file on close.
1461 */
1462bool nfs4_delegation_flush_on_close(const struct inode *inode)
1463{
1464 struct nfs_inode *nfsi = NFS_I(inode);
1465 struct nfs_delegation *delegation;
1466 bool ret = true;
1467
1468 rcu_read_lock();
1469 delegation = rcu_dereference(nfsi->delegation);
1470 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1471 goto out;
1472 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1473 ret = false;
1474out:
1475 rcu_read_unlock();
1476 return ret;
1477}
1478
1479module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
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);