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(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(nr: NFS_DELEGATION_REVOKED, addr: &delegation->flags)) {
43 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
44 atomic_long_dec(v: &nfs_active_delegations);
45 if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
46 nfs_clear_verifier_delegated(inode: delegation->inode);
47 }
48}
49
50static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
51{
52 refcount_inc(r: &delegation->refcount);
53 return delegation;
54}
55
56static void nfs_put_delegation(struct nfs_delegation *delegation)
57{
58 if (refcount_dec_and_test(r: &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(nr: NFS_DELEGATION_REFERENCED, addr: &delegation->flags);
76}
77
78static void nfs_mark_return_delegation(struct nfs_server *server,
79 struct nfs_delegation *delegation)
80{
81 set_bit(nr: NFS_DELEGATION_RETURN, addr: &delegation->flags);
82 set_bit(nr: NFS4CLNT_DELEGRETURN, addr: &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, flags: 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, mark: 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, mark: 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(lock: &flctx->flc_lock);
158restart:
159 list_for_each_entry(fl, list, fl_list) {
160 if (nfs_file_open_context(filp: fl->fl_file)->state != state)
161 continue;
162 spin_unlock(lock: &flctx->flc_lock);
163 status = nfs4_lock_delegation_recall(fl, state, stateid);
164 if (status < 0)
165 goto out;
166 spin_lock(lock: &flctx->flc_lock);
167 }
168 if (list == &flctx->flc_posix) {
169 list = &flctx->flc_flock;
170 goto restart;
171 }
172 spin_unlock(lock: &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(dst: &state->stateid, src: 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(lock: &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(lock: &delegation->lock);
241 nfs4_stateid_copy(dst: &delegation->stateid, src: stateid);
242 delegation->type = type;
243 delegation->pagemod_limit = pagemod_limit;
244 oldcred = delegation->cred;
245 delegation->cred = get_cred(cred);
246 clear_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
247 if (test_and_clear_bit(nr: NFS_DELEGATION_REVOKED,
248 addr: &delegation->flags))
249 atomic_long_inc(v: &nfs_active_delegations);
250 spin_unlock(lock: &delegation->lock);
251 rcu_read_unlock();
252 put_cred(cred: oldcred);
253 trace_nfs4_reclaim_delegation(inode, fmode: 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(lock: &delegation->lock);
268 cred = get_cred(cred: delegation->cred);
269 spin_unlock(lock: &delegation->lock);
270 res = nfs4_proc_delegreturn(inode, cred,
271 stateid: &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(lock: &delegation->lock);
283 if (delegation->inode != NULL)
284 inode = igrab(delegation->inode);
285 if (!inode)
286 set_bit(nr: NFS_DELEGATION_INODE_FREEING, addr: &delegation->flags);
287 spin_unlock(lock: &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(lock: &delegation->lock);
300 if (!test_and_set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags)) {
301 clear_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &delegation->flags);
302 /* Refcount matched in nfs_end_delegation_return() */
303 ret = nfs_get_delegation(delegation);
304 }
305 spin_unlock(lock: &delegation->lock);
306 if (ret)
307 nfs_clear_verifier_delegated(inode: &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(lock: &delegation->lock);
328 clear_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
329 if (err == -EAGAIN) {
330 set_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &delegation->flags);
331 set_bit(nr: NFS4CLNT_DELEGRETURN_DELAYED, addr: &clp->cl_state);
332 }
333 spin_unlock(lock: &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(lock: &delegation->lock);
349 if (!delegation->inode) {
350 spin_unlock(lock: &delegation->lock);
351 return NULL;
352 }
353 list_del_rcu(entry: &delegation->super_list);
354 delegation->inode = NULL;
355 rcu_assign_pointer(nfsi->delegation, NULL);
356 spin_unlock(lock: &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(lock: &clp->cl_lock);
367 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
368 spin_unlock(lock: &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(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(s1: &update->stateid, s2: &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, cred: update->cred);
411 /* smp_mb__before_atomic() is implicit due to xchg() */
412 clear_bit(nr: NFS_DELEGATION_REVOKED, addr: &delegation->flags);
413 atomic_long_inc(v: &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(size: sizeof(*delegation), GFP_KERNEL_ACCOUNT);
441 if (delegation == NULL)
442 return -ENOMEM;
443 nfs4_stateid_copy(dst: &delegation->stateid, src: stateid);
444 refcount_set(r: &delegation->refcount, n: 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 delegation->test_gen = 0;
452 spin_lock_init(&delegation->lock);
453
454 spin_lock(lock: &clp->cl_lock);
455 old_delegation = rcu_dereference_protected(nfsi->delegation,
456 lockdep_is_held(&clp->cl_lock));
457 if (old_delegation == NULL)
458 goto add_new;
459 /* Is this an update of the existing delegation? */
460 if (nfs4_stateid_match_other(dst: &old_delegation->stateid,
461 src: &delegation->stateid)) {
462 spin_lock(lock: &old_delegation->lock);
463 nfs_update_inplace_delegation(delegation: old_delegation,
464 update: delegation);
465 spin_unlock(lock: &old_delegation->lock);
466 goto out;
467 }
468 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
469 /*
470 * Deal with broken servers that hand out two
471 * delegations for the same file.
472 * Allow for upgrades to a WRITE delegation, but
473 * nothing else.
474 */
475 dfprintk(FILE, "%s: server %s handed out "
476 "a duplicate delegation!\n",
477 __func__, clp->cl_hostname);
478 if (delegation->type == old_delegation->type ||
479 !(delegation->type & FMODE_WRITE)) {
480 freeme = delegation;
481 delegation = NULL;
482 goto out;
483 }
484 if (test_and_set_bit(nr: NFS_DELEGATION_RETURNING,
485 addr: &old_delegation->flags))
486 goto out;
487 }
488 freeme = nfs_detach_delegation_locked(nfsi, delegation: old_delegation, clp);
489 if (freeme == NULL)
490 goto out;
491add_new:
492 /*
493 * If we didn't revalidate the change attribute before setting
494 * the delegation, then pre-emptively ask for a full attribute
495 * cache revalidation.
496 */
497 spin_lock(lock: &inode->i_lock);
498 if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
499 nfs_set_cache_invalid(inode,
500 NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
501 NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
502 NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
503 NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
504 NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
505 NFS_INO_INVALID_XATTR);
506 spin_unlock(lock: &inode->i_lock);
507
508 list_add_tail_rcu(new: &delegation->super_list, head: &server->delegations);
509 rcu_assign_pointer(nfsi->delegation, delegation);
510 delegation = NULL;
511
512 atomic_long_inc(v: &nfs_active_delegations);
513
514 trace_nfs4_set_delegation(inode, fmode: type);
515out:
516 spin_unlock(lock: &clp->cl_lock);
517 if (delegation != NULL)
518 __nfs_free_delegation(delegation);
519 if (freeme != NULL) {
520 nfs_do_return_delegation(inode, delegation: freeme, issync: 0);
521 nfs_free_delegation(delegation: freeme);
522 }
523 return status;
524}
525
526/*
527 * Basic procedure for returning a delegation to the server
528 */
529static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
530{
531 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
532 unsigned int mode = O_WRONLY | O_RDWR;
533 int err = 0;
534
535 if (delegation == NULL)
536 return 0;
537
538 if (!issync)
539 mode |= O_NONBLOCK;
540 /* Recall of any remaining application leases */
541 err = break_lease(inode, mode);
542
543 while (err == 0) {
544 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
545 break;
546 err = nfs_delegation_claim_opens(inode, stateid: &delegation->stateid,
547 type: delegation->type);
548 if (!issync || err != -EAGAIN)
549 break;
550 /*
551 * Guard against state recovery
552 */
553 err = nfs4_wait_clnt_recover(clp);
554 }
555
556 if (err) {
557 nfs_abort_delegation_return(delegation, clp, err);
558 goto out;
559 }
560
561 err = nfs_do_return_delegation(inode, delegation, issync);
562out:
563 /* Refcount matched in nfs_start_delegation_return_locked() */
564 nfs_put_delegation(delegation);
565 return err;
566}
567
568static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
569{
570 bool ret = false;
571
572 if (test_and_clear_bit(nr: NFS_DELEGATION_RETURN, addr: &delegation->flags))
573 ret = true;
574 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
575 struct inode *inode;
576
577 spin_lock(lock: &delegation->lock);
578 inode = delegation->inode;
579 if (inode && list_empty(head: &NFS_I(inode)->open_files))
580 ret = true;
581 spin_unlock(lock: &delegation->lock);
582 }
583 if (ret)
584 clear_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
585 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
586 test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
587 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
588 ret = false;
589
590 return ret;
591}
592
593static int nfs_server_return_marked_delegations(struct nfs_server *server,
594 void __always_unused *data)
595{
596 struct nfs_delegation *delegation;
597 struct nfs_delegation *prev;
598 struct inode *inode;
599 struct inode *place_holder = NULL;
600 struct nfs_delegation *place_holder_deleg = NULL;
601 int err = 0;
602
603restart:
604 /*
605 * To avoid quadratic looping we hold a reference
606 * to an inode place_holder. Each time we restart, we
607 * list delegation in the server from the delegations
608 * of that inode.
609 * prev is an RCU-protected pointer to a delegation which
610 * wasn't marked for return and might be a good choice for
611 * the next place_holder.
612 */
613 prev = NULL;
614 delegation = NULL;
615 rcu_read_lock();
616 if (place_holder)
617 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
618 if (!delegation || delegation != place_holder_deleg)
619 delegation = list_entry_rcu(server->delegations.next,
620 struct nfs_delegation, super_list);
621 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
622 struct inode *to_put = NULL;
623
624 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
625 continue;
626 if (!nfs_delegation_need_return(delegation)) {
627 if (nfs4_is_valid_delegation(delegation, flags: 0))
628 prev = delegation;
629 continue;
630 }
631
632 if (prev) {
633 struct inode *tmp = nfs_delegation_grab_inode(delegation: prev);
634 if (tmp) {
635 to_put = place_holder;
636 place_holder = tmp;
637 place_holder_deleg = prev;
638 }
639 }
640
641 inode = nfs_delegation_grab_inode(delegation);
642 if (inode == NULL) {
643 rcu_read_unlock();
644 iput(to_put);
645 goto restart;
646 }
647 delegation = nfs_start_delegation_return_locked(nfsi: NFS_I(inode));
648 rcu_read_unlock();
649
650 iput(to_put);
651
652 err = nfs_end_delegation_return(inode, delegation, issync: 0);
653 iput(inode);
654 cond_resched();
655 if (!err)
656 goto restart;
657 set_bit(nr: NFS4CLNT_DELEGRETURN, addr: &server->nfs_client->cl_state);
658 goto out;
659 }
660 rcu_read_unlock();
661out:
662 iput(place_holder);
663 return err;
664}
665
666static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
667{
668 struct nfs_delegation *d;
669 bool ret = false;
670
671 list_for_each_entry_rcu (d, &server->delegations, super_list) {
672 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
673 continue;
674 nfs_mark_return_delegation(server, delegation: d);
675 clear_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &d->flags);
676 ret = true;
677 }
678 return ret;
679}
680
681static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
682{
683 struct nfs_server *server;
684 bool ret = false;
685
686 if (!test_and_clear_bit(nr: NFS4CLNT_DELEGRETURN_DELAYED, addr: &clp->cl_state))
687 goto out;
688 rcu_read_lock();
689 list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
690 if (nfs_server_clear_delayed_delegations(server))
691 ret = true;
692 }
693 rcu_read_unlock();
694out:
695 return ret;
696}
697
698/**
699 * nfs_client_return_marked_delegations - return previously marked delegations
700 * @clp: nfs_client to process
701 *
702 * Note that this function is designed to be called by the state
703 * manager thread. For this reason, it cannot flush the dirty data,
704 * since that could deadlock in case of a state recovery error.
705 *
706 * Returns zero on success, or a negative errno value.
707 */
708int nfs_client_return_marked_delegations(struct nfs_client *clp)
709{
710 int err = nfs_client_for_each_server(
711 clp, fn: nfs_server_return_marked_delegations, NULL);
712 if (err)
713 return err;
714 /* If a return was delayed, sleep to prevent hard looping */
715 if (nfs_client_clear_delayed_delegations(clp))
716 ssleep(seconds: 1);
717 return 0;
718}
719
720/**
721 * nfs_inode_evict_delegation - return delegation, don't reclaim opens
722 * @inode: inode to process
723 *
724 * Does not protect against delegation reclaims, therefore really only safe
725 * to be called from nfs4_clear_inode(). Guaranteed to always free
726 * the delegation structure.
727 */
728void nfs_inode_evict_delegation(struct inode *inode)
729{
730 struct nfs_delegation *delegation;
731
732 delegation = nfs_inode_detach_delegation(inode);
733 if (delegation != NULL) {
734 set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
735 set_bit(nr: NFS_DELEGATION_INODE_FREEING, addr: &delegation->flags);
736 nfs_do_return_delegation(inode, delegation, issync: 1);
737 nfs_free_delegation(delegation);
738 }
739}
740
741/**
742 * nfs4_inode_return_delegation - synchronously return a delegation
743 * @inode: inode to process
744 *
745 * This routine will always flush any dirty data to disk on the
746 * assumption that if we need to return the delegation, then
747 * we should stop caching.
748 *
749 * Returns zero on success, or a negative errno value.
750 */
751int nfs4_inode_return_delegation(struct inode *inode)
752{
753 struct nfs_inode *nfsi = NFS_I(inode);
754 struct nfs_delegation *delegation;
755
756 delegation = nfs_start_delegation_return(nfsi);
757 if (delegation != NULL) {
758 /* Synchronous recall of any application leases */
759 break_lease(inode, O_WRONLY | O_RDWR);
760 if (S_ISREG(inode->i_mode))
761 nfs_wb_all(inode);
762 return nfs_end_delegation_return(inode, delegation, issync: 1);
763 }
764 return 0;
765}
766
767/**
768 * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
769 * @inode: inode to process
770 *
771 * This routine is called on file close in order to determine if the
772 * inode delegation needs to be returned immediately.
773 */
774void nfs4_inode_return_delegation_on_close(struct inode *inode)
775{
776 struct nfs_delegation *delegation;
777 struct nfs_delegation *ret = NULL;
778
779 if (!inode)
780 return;
781 rcu_read_lock();
782 delegation = nfs4_get_valid_delegation(inode);
783 if (!delegation)
784 goto out;
785 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
786 atomic_long_read(v: &nfs_active_delegations) >= nfs_delegation_watermark) {
787 spin_lock(lock: &delegation->lock);
788 if (delegation->inode &&
789 list_empty(head: &NFS_I(inode)->open_files) &&
790 !test_and_set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags)) {
791 clear_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
792 /* Refcount matched in nfs_end_delegation_return() */
793 ret = nfs_get_delegation(delegation);
794 }
795 spin_unlock(lock: &delegation->lock);
796 if (ret)
797 nfs_clear_verifier_delegated(inode);
798 }
799out:
800 rcu_read_unlock();
801 nfs_end_delegation_return(inode, delegation: ret, issync: 0);
802}
803
804/**
805 * nfs4_inode_make_writeable
806 * @inode: pointer to inode
807 *
808 * Make the inode writeable by returning the delegation if necessary
809 *
810 * Returns zero on success, or a negative errno value.
811 */
812int nfs4_inode_make_writeable(struct inode *inode)
813{
814 struct nfs_delegation *delegation;
815
816 rcu_read_lock();
817 delegation = nfs4_get_valid_delegation(inode);
818 if (delegation == NULL ||
819 (nfs4_has_session(clp: NFS_SERVER(inode)->nfs_client) &&
820 (delegation->type & FMODE_WRITE))) {
821 rcu_read_unlock();
822 return 0;
823 }
824 rcu_read_unlock();
825 return nfs4_inode_return_delegation(inode);
826}
827
828static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
829 struct nfs_delegation *delegation)
830{
831 set_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
832 set_bit(nr: NFS4CLNT_DELEGRETURN, addr: &server->nfs_client->cl_state);
833}
834
835static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
836{
837 struct nfs_delegation *delegation;
838 bool ret = false;
839
840 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
841 nfs_mark_return_delegation(server, delegation);
842 ret = true;
843 }
844 return ret;
845}
846
847static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
848{
849 struct nfs_server *server;
850
851 rcu_read_lock();
852 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
853 nfs_server_mark_return_all_delegations(server);
854 rcu_read_unlock();
855}
856
857static void nfs_delegation_run_state_manager(struct nfs_client *clp)
858{
859 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
860 nfs4_schedule_state_manager(clp);
861}
862
863/**
864 * nfs_expire_all_delegations
865 * @clp: client to process
866 *
867 */
868void nfs_expire_all_delegations(struct nfs_client *clp)
869{
870 nfs_client_mark_return_all_delegations(clp);
871 nfs_delegation_run_state_manager(clp);
872}
873
874/**
875 * nfs_server_return_all_delegations - return delegations for one superblock
876 * @server: pointer to nfs_server to process
877 *
878 */
879void nfs_server_return_all_delegations(struct nfs_server *server)
880{
881 struct nfs_client *clp = server->nfs_client;
882 bool need_wait;
883
884 if (clp == NULL)
885 return;
886
887 rcu_read_lock();
888 need_wait = nfs_server_mark_return_all_delegations(server);
889 rcu_read_unlock();
890
891 if (need_wait) {
892 nfs4_schedule_state_manager(clp);
893 nfs4_wait_clnt_recover(clp);
894 }
895}
896
897static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
898 fmode_t flags)
899{
900 struct nfs_delegation *delegation;
901
902 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
903 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
904 continue;
905 if (delegation->type & flags)
906 nfs_mark_return_if_closed_delegation(server, delegation);
907 }
908}
909
910static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
911 fmode_t flags)
912{
913 struct nfs_server *server;
914
915 rcu_read_lock();
916 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
917 nfs_mark_return_unused_delegation_types(server, flags);
918 rcu_read_unlock();
919}
920
921static void nfs_revoke_delegation(struct inode *inode,
922 const nfs4_stateid *stateid)
923{
924 struct nfs_delegation *delegation;
925 nfs4_stateid tmp;
926 bool ret = false;
927
928 rcu_read_lock();
929 delegation = rcu_dereference(NFS_I(inode)->delegation);
930 if (delegation == NULL)
931 goto out;
932 if (stateid == NULL) {
933 nfs4_stateid_copy(dst: &tmp, src: &delegation->stateid);
934 stateid = &tmp;
935 } else {
936 if (!nfs4_stateid_match_other(dst: stateid, src: &delegation->stateid))
937 goto out;
938 spin_lock(lock: &delegation->lock);
939 if (stateid->seqid) {
940 if (nfs4_stateid_is_newer(s1: &delegation->stateid, s2: stateid)) {
941 spin_unlock(lock: &delegation->lock);
942 goto out;
943 }
944 delegation->stateid.seqid = stateid->seqid;
945 }
946 spin_unlock(lock: &delegation->lock);
947 }
948 nfs_mark_delegation_revoked(delegation);
949 ret = true;
950out:
951 rcu_read_unlock();
952 if (ret)
953 nfs_inode_find_state_and_recover(inode, stateid);
954}
955
956void nfs_remove_bad_delegation(struct inode *inode,
957 const nfs4_stateid *stateid)
958{
959 nfs_revoke_delegation(inode, stateid);
960}
961EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
962
963void nfs_delegation_mark_returned(struct inode *inode,
964 const nfs4_stateid *stateid)
965{
966 struct nfs_delegation *delegation;
967
968 if (!inode)
969 return;
970
971 rcu_read_lock();
972 delegation = rcu_dereference(NFS_I(inode)->delegation);
973 if (!delegation)
974 goto out_rcu_unlock;
975
976 spin_lock(lock: &delegation->lock);
977 if (!nfs4_stateid_match_other(dst: stateid, src: &delegation->stateid))
978 goto out_spin_unlock;
979 if (stateid->seqid) {
980 /* If delegation->stateid is newer, dont mark as returned */
981 if (nfs4_stateid_is_newer(s1: &delegation->stateid, s2: stateid))
982 goto out_clear_returning;
983 if (delegation->stateid.seqid != stateid->seqid)
984 delegation->stateid.seqid = stateid->seqid;
985 }
986
987 nfs_mark_delegation_revoked(delegation);
988
989out_clear_returning:
990 clear_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
991out_spin_unlock:
992 spin_unlock(lock: &delegation->lock);
993out_rcu_unlock:
994 rcu_read_unlock();
995
996 nfs_inode_find_state_and_recover(inode, stateid);
997}
998
999/**
1000 * nfs_expire_unused_delegation_types
1001 * @clp: client to process
1002 * @flags: delegation types to expire
1003 *
1004 */
1005void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1006{
1007 nfs_client_mark_return_unused_delegation_types(clp, flags);
1008 nfs_delegation_run_state_manager(clp);
1009}
1010
1011static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1012{
1013 struct nfs_delegation *delegation;
1014
1015 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1016 if (test_and_clear_bit(nr: NFS_DELEGATION_REFERENCED, addr: &delegation->flags))
1017 continue;
1018 nfs_mark_return_if_closed_delegation(server, delegation);
1019 }
1020}
1021
1022/**
1023 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1024 * @clp: nfs_client to process
1025 *
1026 */
1027void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
1028{
1029 struct nfs_server *server;
1030
1031 rcu_read_lock();
1032 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1033 nfs_mark_return_unreferenced_delegations(server);
1034 rcu_read_unlock();
1035
1036 nfs_delegation_run_state_manager(clp);
1037}
1038
1039/**
1040 * nfs_async_inode_return_delegation - asynchronously return a delegation
1041 * @inode: inode to process
1042 * @stateid: state ID information
1043 *
1044 * Returns zero on success, or a negative errno value.
1045 */
1046int nfs_async_inode_return_delegation(struct inode *inode,
1047 const nfs4_stateid *stateid)
1048{
1049 struct nfs_server *server = NFS_SERVER(inode);
1050 struct nfs_client *clp = server->nfs_client;
1051 struct nfs_delegation *delegation;
1052
1053 rcu_read_lock();
1054 delegation = nfs4_get_valid_delegation(inode);
1055 if (delegation == NULL)
1056 goto out_enoent;
1057 if (stateid != NULL &&
1058 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1059 goto out_enoent;
1060 nfs_mark_return_delegation(server, delegation);
1061 rcu_read_unlock();
1062
1063 /* If there are any application leases or delegations, recall them */
1064 break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1065
1066 nfs_delegation_run_state_manager(clp);
1067 return 0;
1068out_enoent:
1069 rcu_read_unlock();
1070 return -ENOENT;
1071}
1072
1073static struct inode *
1074nfs_delegation_find_inode_server(struct nfs_server *server,
1075 const struct nfs_fh *fhandle)
1076{
1077 struct nfs_delegation *delegation;
1078 struct super_block *freeme = NULL;
1079 struct inode *res = NULL;
1080
1081 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1082 spin_lock(lock: &delegation->lock);
1083 if (delegation->inode != NULL &&
1084 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1085 nfs_compare_fh(a: fhandle, b: &NFS_I(inode: delegation->inode)->fh) == 0) {
1086 if (nfs_sb_active(sb: server->super)) {
1087 freeme = server->super;
1088 res = igrab(delegation->inode);
1089 }
1090 spin_unlock(lock: &delegation->lock);
1091 if (res != NULL)
1092 return res;
1093 if (freeme) {
1094 rcu_read_unlock();
1095 nfs_sb_deactive(sb: freeme);
1096 rcu_read_lock();
1097 }
1098 return ERR_PTR(error: -EAGAIN);
1099 }
1100 spin_unlock(lock: &delegation->lock);
1101 }
1102 return ERR_PTR(error: -ENOENT);
1103}
1104
1105/**
1106 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1107 * @clp: client state handle
1108 * @fhandle: filehandle from a delegation recall
1109 *
1110 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1111 * cannot be found.
1112 */
1113struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1114 const struct nfs_fh *fhandle)
1115{
1116 struct nfs_server *server;
1117 struct inode *res;
1118
1119 rcu_read_lock();
1120 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1121 res = nfs_delegation_find_inode_server(server, fhandle);
1122 if (res != ERR_PTR(error: -ENOENT)) {
1123 rcu_read_unlock();
1124 return res;
1125 }
1126 }
1127 rcu_read_unlock();
1128 return ERR_PTR(error: -ENOENT);
1129}
1130
1131static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1132{
1133 struct nfs_delegation *delegation;
1134
1135 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1136 /*
1137 * If the delegation may have been admin revoked, then we
1138 * cannot reclaim it.
1139 */
1140 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1141 continue;
1142 set_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
1143 }
1144}
1145
1146/**
1147 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1148 * @clp: nfs_client to process
1149 *
1150 */
1151void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1152{
1153 struct nfs_server *server;
1154
1155 rcu_read_lock();
1156 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1157 nfs_delegation_mark_reclaim_server(server);
1158 rcu_read_unlock();
1159}
1160
1161static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1162 void __always_unused *data)
1163{
1164 struct nfs_delegation *delegation;
1165 struct inode *inode;
1166restart:
1167 rcu_read_lock();
1168restart_locked:
1169 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1170 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1171 &delegation->flags) ||
1172 test_bit(NFS_DELEGATION_RETURNING,
1173 &delegation->flags) ||
1174 test_bit(NFS_DELEGATION_NEED_RECLAIM,
1175 &delegation->flags) == 0)
1176 continue;
1177 inode = nfs_delegation_grab_inode(delegation);
1178 if (inode == NULL)
1179 goto restart_locked;
1180 delegation = nfs_start_delegation_return_locked(nfsi: NFS_I(inode));
1181 rcu_read_unlock();
1182 if (delegation != NULL) {
1183 if (nfs_detach_delegation(nfsi: NFS_I(inode), delegation,
1184 server) != NULL)
1185 nfs_free_delegation(delegation);
1186 /* Match nfs_start_delegation_return_locked */
1187 nfs_put_delegation(delegation);
1188 }
1189 iput(inode);
1190 cond_resched();
1191 goto restart;
1192 }
1193 rcu_read_unlock();
1194 return 0;
1195}
1196
1197/**
1198 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1199 * @clp: nfs_client to process
1200 *
1201 */
1202void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1203{
1204 nfs_client_for_each_server(clp, fn: nfs_server_reap_unclaimed_delegations,
1205 NULL);
1206}
1207
1208static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1209{
1210 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1211 BIT(NFS4CLNT_LEASE_EXPIRED) |
1212 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1213}
1214
1215static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1216 struct nfs_delegation *delegation)
1217{
1218 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1219 return;
1220 clear_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
1221 set_bit(nr: NFS_DELEGATION_TEST_EXPIRED, addr: &delegation->flags);
1222 set_bit(nr: NFS4CLNT_DELEGATION_EXPIRED, addr: &server->nfs_client->cl_state);
1223}
1224
1225static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1226 struct inode *inode)
1227{
1228 struct nfs_delegation *delegation;
1229
1230 rcu_read_lock();
1231 delegation = rcu_dereference(NFS_I(inode)->delegation);
1232 if (delegation)
1233 nfs_mark_test_expired_delegation(server, delegation);
1234 rcu_read_unlock();
1235
1236}
1237
1238static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1239{
1240 struct nfs_delegation *delegation;
1241
1242 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1243 nfs_mark_test_expired_delegation(server, delegation);
1244}
1245
1246/**
1247 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1248 * @clp: nfs_client to process
1249 *
1250 * Iterates through all the delegations associated with this server and
1251 * marks them as needing to be checked for validity.
1252 */
1253void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1254{
1255 struct nfs_server *server;
1256
1257 rcu_read_lock();
1258 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1259 nfs_delegation_mark_test_expired_server(server);
1260 rcu_read_unlock();
1261}
1262
1263/**
1264 * nfs_test_expired_all_delegations - test all delegations for a client
1265 * @clp: nfs_client to process
1266 *
1267 * Helper for handling "recallable state revoked" status from server.
1268 */
1269void nfs_test_expired_all_delegations(struct nfs_client *clp)
1270{
1271 nfs_mark_test_expired_all_delegations(clp);
1272 nfs4_schedule_state_manager(clp);
1273}
1274
1275static void
1276nfs_delegation_test_free_expired(struct inode *inode,
1277 nfs4_stateid *stateid,
1278 const struct cred *cred)
1279{
1280 struct nfs_server *server = NFS_SERVER(inode);
1281 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1282 int status;
1283
1284 if (!cred)
1285 return;
1286 status = ops->test_and_free_expired(server, stateid, cred);
1287 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1288 nfs_remove_bad_delegation(inode, stateid);
1289}
1290
1291static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1292 void __always_unused *data)
1293{
1294 struct nfs_delegation *delegation;
1295 struct inode *inode;
1296 const struct cred *cred;
1297 nfs4_stateid stateid;
1298 unsigned long gen = ++server->delegation_gen;
1299
1300restart:
1301 rcu_read_lock();
1302restart_locked:
1303 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1304 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1305 &delegation->flags) ||
1306 test_bit(NFS_DELEGATION_RETURNING,
1307 &delegation->flags) ||
1308 test_bit(NFS_DELEGATION_TEST_EXPIRED,
1309 &delegation->flags) == 0 ||
1310 delegation->test_gen == gen)
1311 continue;
1312 inode = nfs_delegation_grab_inode(delegation);
1313 if (inode == NULL)
1314 goto restart_locked;
1315 spin_lock(lock: &delegation->lock);
1316 cred = get_cred_rcu(cred: delegation->cred);
1317 nfs4_stateid_copy(dst: &stateid, src: &delegation->stateid);
1318 spin_unlock(lock: &delegation->lock);
1319 delegation->test_gen = gen;
1320 clear_bit(nr: NFS_DELEGATION_TEST_EXPIRED, addr: &delegation->flags);
1321 rcu_read_unlock();
1322 nfs_delegation_test_free_expired(inode, stateid: &stateid, cred);
1323 put_cred(cred);
1324 if (!nfs4_server_rebooted(clp: server->nfs_client)) {
1325 iput(inode);
1326 cond_resched();
1327 goto restart;
1328 }
1329 nfs_inode_mark_test_expired_delegation(server,inode);
1330 iput(inode);
1331 return -EAGAIN;
1332 }
1333 rcu_read_unlock();
1334 return 0;
1335}
1336
1337/**
1338 * nfs_reap_expired_delegations - reap expired delegations
1339 * @clp: nfs_client to process
1340 *
1341 * Iterates through all the delegations associated with this server and
1342 * checks if they have may have been revoked. This function is usually
1343 * expected to be called in cases where the server may have lost its
1344 * lease.
1345 */
1346void nfs_reap_expired_delegations(struct nfs_client *clp)
1347{
1348 nfs_client_for_each_server(clp, fn: nfs_server_reap_expired_delegations,
1349 NULL);
1350}
1351
1352void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1353 const nfs4_stateid *stateid)
1354{
1355 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1356 struct nfs_delegation *delegation;
1357 bool found = false;
1358
1359 rcu_read_lock();
1360 delegation = rcu_dereference(NFS_I(inode)->delegation);
1361 if (delegation &&
1362 nfs4_stateid_match_or_older(dst: &delegation->stateid, src: stateid) &&
1363 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1364 nfs_mark_test_expired_delegation(server: NFS_SERVER(inode), delegation);
1365 found = true;
1366 }
1367 rcu_read_unlock();
1368 if (found)
1369 nfs4_schedule_state_manager(clp);
1370}
1371
1372/**
1373 * nfs_delegations_present - check for existence of delegations
1374 * @clp: client state handle
1375 *
1376 * Returns one if there are any nfs_delegation structures attached
1377 * to this nfs_client.
1378 */
1379int nfs_delegations_present(struct nfs_client *clp)
1380{
1381 struct nfs_server *server;
1382 int ret = 0;
1383
1384 rcu_read_lock();
1385 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1386 if (!list_empty(head: &server->delegations)) {
1387 ret = 1;
1388 break;
1389 }
1390 rcu_read_unlock();
1391 return ret;
1392}
1393
1394/**
1395 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1396 * @dst: stateid to refresh
1397 * @inode: inode to check
1398 *
1399 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1400 * that matches our delegation stateid. Otherwise "false" is returned.
1401 */
1402bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1403{
1404 struct nfs_delegation *delegation;
1405 bool ret = false;
1406 if (!inode)
1407 goto out;
1408
1409 rcu_read_lock();
1410 delegation = rcu_dereference(NFS_I(inode)->delegation);
1411 if (delegation != NULL &&
1412 nfs4_stateid_match_other(dst, src: &delegation->stateid) &&
1413 nfs4_stateid_is_newer(s1: &delegation->stateid, s2: dst) &&
1414 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1415 dst->seqid = delegation->stateid.seqid;
1416 ret = true;
1417 }
1418 rcu_read_unlock();
1419out:
1420 return ret;
1421}
1422
1423/**
1424 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1425 * @inode: inode to check
1426 * @flags: delegation type requirement
1427 * @dst: stateid data structure to fill in
1428 * @cred: optional argument to retrieve credential
1429 *
1430 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1431 * otherwise "false" is returned.
1432 */
1433bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1434 nfs4_stateid *dst, const struct cred **cred)
1435{
1436 struct nfs_inode *nfsi = NFS_I(inode);
1437 struct nfs_delegation *delegation;
1438 bool ret = false;
1439
1440 flags &= FMODE_READ|FMODE_WRITE;
1441 rcu_read_lock();
1442 delegation = rcu_dereference(nfsi->delegation);
1443 if (!delegation)
1444 goto out;
1445 spin_lock(lock: &delegation->lock);
1446 ret = nfs4_is_valid_delegation(delegation, flags);
1447 if (ret) {
1448 nfs4_stateid_copy(dst, src: &delegation->stateid);
1449 nfs_mark_delegation_referenced(delegation);
1450 if (cred)
1451 *cred = get_cred(cred: delegation->cred);
1452 }
1453 spin_unlock(lock: &delegation->lock);
1454out:
1455 rcu_read_unlock();
1456 return ret;
1457}
1458
1459/**
1460 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1461 * @inode: inode to check
1462 *
1463 * This function checks the number of outstanding writes to the file
1464 * against the delegation 'space_limit' field to see if
1465 * the spec requires us to flush the file on close.
1466 */
1467bool nfs4_delegation_flush_on_close(const struct inode *inode)
1468{
1469 struct nfs_inode *nfsi = NFS_I(inode);
1470 struct nfs_delegation *delegation;
1471 bool ret = true;
1472
1473 rcu_read_lock();
1474 delegation = rcu_dereference(nfsi->delegation);
1475 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1476 goto out;
1477 if (atomic_long_read(v: &nfsi->nrequests) < delegation->pagemod_limit)
1478 ret = false;
1479out:
1480 rcu_read_unlock();
1481 return ret;
1482}
1483
1484module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
1485

source code of linux/fs/nfs/delegation.c