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 for_each_file_lock(fl, list) {
160 if (nfs_file_open_context(filp: fl->c.flc_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 int err;
185
186again:
187 rcu_read_lock();
188 list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
189 state = ctx->state;
190 if (state == NULL)
191 continue;
192 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
193 continue;
194 if (!nfs4_valid_open_stateid(state))
195 continue;
196 if (!nfs4_stateid_match(dst: &state->stateid, src: stateid))
197 continue;
198 if (!get_nfs_open_context(ctx))
199 continue;
200 rcu_read_unlock();
201 sp = state->owner;
202 /* Block nfs4_proc_unlck */
203 mutex_lock(&sp->so_delegreturn_mutex);
204 err = nfs4_open_delegation_recall(ctx, state, stateid);
205 if (!err)
206 err = nfs_delegation_claim_locks(state, stateid);
207 mutex_unlock(lock: &sp->so_delegreturn_mutex);
208 put_nfs_open_context(ctx);
209 if (err != 0)
210 return err;
211 goto again;
212 }
213 rcu_read_unlock();
214 return 0;
215}
216
217/**
218 * nfs_inode_reclaim_delegation - process a delegation reclaim request
219 * @inode: inode to process
220 * @cred: credential to use for request
221 * @type: delegation type
222 * @stateid: delegation stateid
223 * @pagemod_limit: write delegation "space_limit"
224 *
225 */
226void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
227 fmode_t type, const nfs4_stateid *stateid,
228 unsigned long pagemod_limit)
229{
230 struct nfs_delegation *delegation;
231 const struct cred *oldcred = NULL;
232
233 rcu_read_lock();
234 delegation = rcu_dereference(NFS_I(inode)->delegation);
235 if (delegation != NULL) {
236 spin_lock(lock: &delegation->lock);
237 nfs4_stateid_copy(dst: &delegation->stateid, src: stateid);
238 delegation->type = type;
239 delegation->pagemod_limit = pagemod_limit;
240 oldcred = delegation->cred;
241 delegation->cred = get_cred(cred);
242 clear_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
243 if (test_and_clear_bit(nr: NFS_DELEGATION_REVOKED,
244 addr: &delegation->flags))
245 atomic_long_inc(v: &nfs_active_delegations);
246 spin_unlock(lock: &delegation->lock);
247 rcu_read_unlock();
248 put_cred(cred: oldcred);
249 trace_nfs4_reclaim_delegation(inode, fmode: type);
250 } else {
251 rcu_read_unlock();
252 nfs_inode_set_delegation(inode, cred, type, stateid,
253 pagemod_limit);
254 }
255}
256
257static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
258{
259 const struct cred *cred;
260 int res = 0;
261
262 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
263 spin_lock(lock: &delegation->lock);
264 cred = get_cred(cred: delegation->cred);
265 spin_unlock(lock: &delegation->lock);
266 res = nfs4_proc_delegreturn(inode, cred,
267 stateid: &delegation->stateid,
268 issync);
269 put_cred(cred);
270 }
271 return res;
272}
273
274static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
275{
276 struct inode *inode = NULL;
277
278 spin_lock(lock: &delegation->lock);
279 if (delegation->inode != NULL)
280 inode = igrab(delegation->inode);
281 if (!inode)
282 set_bit(nr: NFS_DELEGATION_INODE_FREEING, addr: &delegation->flags);
283 spin_unlock(lock: &delegation->lock);
284 return inode;
285}
286
287static struct nfs_delegation *
288nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
289{
290 struct nfs_delegation *ret = NULL;
291 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
292
293 if (delegation == NULL)
294 goto out;
295 spin_lock(lock: &delegation->lock);
296 if (!test_and_set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags)) {
297 clear_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &delegation->flags);
298 /* Refcount matched in nfs_end_delegation_return() */
299 ret = nfs_get_delegation(delegation);
300 }
301 spin_unlock(lock: &delegation->lock);
302 if (ret)
303 nfs_clear_verifier_delegated(inode: &nfsi->vfs_inode);
304out:
305 return ret;
306}
307
308static struct nfs_delegation *
309nfs_start_delegation_return(struct nfs_inode *nfsi)
310{
311 struct nfs_delegation *delegation;
312
313 rcu_read_lock();
314 delegation = nfs_start_delegation_return_locked(nfsi);
315 rcu_read_unlock();
316 return delegation;
317}
318
319static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
320 struct nfs_client *clp, int err)
321{
322
323 spin_lock(lock: &delegation->lock);
324 clear_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
325 if (err == -EAGAIN) {
326 set_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &delegation->flags);
327 set_bit(nr: NFS4CLNT_DELEGRETURN_DELAYED, addr: &clp->cl_state);
328 }
329 spin_unlock(lock: &delegation->lock);
330}
331
332static struct nfs_delegation *
333nfs_detach_delegation_locked(struct nfs_inode *nfsi,
334 struct nfs_delegation *delegation,
335 struct nfs_client *clp)
336{
337 struct nfs_delegation *deleg_cur =
338 rcu_dereference_protected(nfsi->delegation,
339 lockdep_is_held(&clp->cl_lock));
340
341 if (deleg_cur == NULL || delegation != deleg_cur)
342 return NULL;
343
344 spin_lock(lock: &delegation->lock);
345 if (!delegation->inode) {
346 spin_unlock(lock: &delegation->lock);
347 return NULL;
348 }
349 list_del_rcu(entry: &delegation->super_list);
350 delegation->inode = NULL;
351 rcu_assign_pointer(nfsi->delegation, NULL);
352 spin_unlock(lock: &delegation->lock);
353 return delegation;
354}
355
356static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
357 struct nfs_delegation *delegation,
358 struct nfs_server *server)
359{
360 struct nfs_client *clp = server->nfs_client;
361
362 spin_lock(lock: &clp->cl_lock);
363 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
364 spin_unlock(lock: &clp->cl_lock);
365 return delegation;
366}
367
368static struct nfs_delegation *
369nfs_inode_detach_delegation(struct inode *inode)
370{
371 struct nfs_inode *nfsi = NFS_I(inode);
372 struct nfs_server *server = NFS_SERVER(inode);
373 struct nfs_delegation *delegation;
374
375 rcu_read_lock();
376 delegation = rcu_dereference(nfsi->delegation);
377 if (delegation != NULL)
378 delegation = nfs_detach_delegation(nfsi, delegation, server);
379 rcu_read_unlock();
380 return delegation;
381}
382
383static void
384nfs_update_delegation_cred(struct nfs_delegation *delegation,
385 const struct cred *cred)
386{
387 const struct cred *old;
388
389 if (cred_fscmp(delegation->cred, cred) != 0) {
390 old = xchg(&delegation->cred, get_cred(cred));
391 put_cred(cred: old);
392 }
393}
394
395static void
396nfs_update_inplace_delegation(struct nfs_delegation *delegation,
397 const struct nfs_delegation *update)
398{
399 if (nfs4_stateid_is_newer(s1: &update->stateid, s2: &delegation->stateid)) {
400 delegation->stateid.seqid = update->stateid.seqid;
401 smp_wmb();
402 delegation->type = update->type;
403 delegation->pagemod_limit = update->pagemod_limit;
404 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
405 delegation->change_attr = update->change_attr;
406 nfs_update_delegation_cred(delegation, cred: update->cred);
407 /* smp_mb__before_atomic() is implicit due to xchg() */
408 clear_bit(nr: NFS_DELEGATION_REVOKED, addr: &delegation->flags);
409 atomic_long_inc(v: &nfs_active_delegations);
410 }
411 }
412}
413
414/**
415 * nfs_inode_set_delegation - set up a delegation on an inode
416 * @inode: inode to which delegation applies
417 * @cred: cred to use for subsequent delegation processing
418 * @type: delegation type
419 * @stateid: delegation stateid
420 * @pagemod_limit: write delegation "space_limit"
421 *
422 * Returns zero on success, or a negative errno value.
423 */
424int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
425 fmode_t type,
426 const nfs4_stateid *stateid,
427 unsigned long pagemod_limit)
428{
429 struct nfs_server *server = NFS_SERVER(inode);
430 struct nfs_client *clp = server->nfs_client;
431 struct nfs_inode *nfsi = NFS_I(inode);
432 struct nfs_delegation *delegation, *old_delegation;
433 struct nfs_delegation *freeme = NULL;
434 int status = 0;
435
436 delegation = kmalloc(size: sizeof(*delegation), GFP_KERNEL_ACCOUNT);
437 if (delegation == NULL)
438 return -ENOMEM;
439 nfs4_stateid_copy(dst: &delegation->stateid, src: stateid);
440 refcount_set(r: &delegation->refcount, n: 1);
441 delegation->type = type;
442 delegation->pagemod_limit = pagemod_limit;
443 delegation->change_attr = inode_peek_iversion_raw(inode);
444 delegation->cred = get_cred(cred);
445 delegation->inode = inode;
446 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
447 delegation->test_gen = 0;
448 spin_lock_init(&delegation->lock);
449
450 spin_lock(lock: &clp->cl_lock);
451 old_delegation = rcu_dereference_protected(nfsi->delegation,
452 lockdep_is_held(&clp->cl_lock));
453 if (old_delegation == NULL)
454 goto add_new;
455 /* Is this an update of the existing delegation? */
456 if (nfs4_stateid_match_other(dst: &old_delegation->stateid,
457 src: &delegation->stateid)) {
458 spin_lock(lock: &old_delegation->lock);
459 nfs_update_inplace_delegation(delegation: old_delegation,
460 update: delegation);
461 spin_unlock(lock: &old_delegation->lock);
462 goto out;
463 }
464 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
465 /*
466 * Deal with broken servers that hand out two
467 * delegations for the same file.
468 * Allow for upgrades to a WRITE delegation, but
469 * nothing else.
470 */
471 dfprintk(FILE, "%s: server %s handed out "
472 "a duplicate delegation!\n",
473 __func__, clp->cl_hostname);
474 if (delegation->type == old_delegation->type ||
475 !(delegation->type & FMODE_WRITE)) {
476 freeme = delegation;
477 delegation = NULL;
478 goto out;
479 }
480 if (test_and_set_bit(nr: NFS_DELEGATION_RETURNING,
481 addr: &old_delegation->flags))
482 goto out;
483 }
484 freeme = nfs_detach_delegation_locked(nfsi, delegation: old_delegation, clp);
485 if (freeme == NULL)
486 goto out;
487add_new:
488 /*
489 * If we didn't revalidate the change attribute before setting
490 * the delegation, then pre-emptively ask for a full attribute
491 * cache revalidation.
492 */
493 spin_lock(lock: &inode->i_lock);
494 if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
495 nfs_set_cache_invalid(inode,
496 NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
497 NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
498 NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
499 NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
500 NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
501 NFS_INO_INVALID_XATTR);
502 spin_unlock(lock: &inode->i_lock);
503
504 list_add_tail_rcu(new: &delegation->super_list, head: &server->delegations);
505 rcu_assign_pointer(nfsi->delegation, delegation);
506 delegation = NULL;
507
508 atomic_long_inc(v: &nfs_active_delegations);
509
510 trace_nfs4_set_delegation(inode, fmode: type);
511out:
512 spin_unlock(lock: &clp->cl_lock);
513 if (delegation != NULL)
514 __nfs_free_delegation(delegation);
515 if (freeme != NULL) {
516 nfs_do_return_delegation(inode, delegation: freeme, issync: 0);
517 nfs_free_delegation(delegation: freeme);
518 }
519 return status;
520}
521
522/*
523 * Basic procedure for returning a delegation to the server
524 */
525static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
526{
527 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
528 unsigned int mode = O_WRONLY | O_RDWR;
529 int err = 0;
530
531 if (delegation == NULL)
532 return 0;
533
534 if (!issync)
535 mode |= O_NONBLOCK;
536 /* Recall of any remaining application leases */
537 err = break_lease(inode, mode);
538
539 while (err == 0) {
540 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
541 break;
542 err = nfs_delegation_claim_opens(inode, stateid: &delegation->stateid,
543 type: delegation->type);
544 if (!issync || err != -EAGAIN)
545 break;
546 /*
547 * Guard against state recovery
548 */
549 err = nfs4_wait_clnt_recover(clp);
550 }
551
552 if (err) {
553 nfs_abort_delegation_return(delegation, clp, err);
554 goto out;
555 }
556
557 err = nfs_do_return_delegation(inode, delegation, issync);
558out:
559 /* Refcount matched in nfs_start_delegation_return_locked() */
560 nfs_put_delegation(delegation);
561 return err;
562}
563
564static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
565{
566 bool ret = false;
567
568 if (test_and_clear_bit(nr: NFS_DELEGATION_RETURN, addr: &delegation->flags))
569 ret = true;
570 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
571 struct inode *inode;
572
573 spin_lock(lock: &delegation->lock);
574 inode = delegation->inode;
575 if (inode && list_empty(head: &NFS_I(inode)->open_files))
576 ret = true;
577 spin_unlock(lock: &delegation->lock);
578 }
579 if (ret)
580 clear_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
581 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
582 test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
583 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
584 ret = false;
585
586 return ret;
587}
588
589static int nfs_server_return_marked_delegations(struct nfs_server *server,
590 void __always_unused *data)
591{
592 struct nfs_delegation *delegation;
593 struct nfs_delegation *prev;
594 struct inode *inode;
595 struct inode *place_holder = NULL;
596 struct nfs_delegation *place_holder_deleg = NULL;
597 int err = 0;
598
599restart:
600 /*
601 * To avoid quadratic looping we hold a reference
602 * to an inode place_holder. Each time we restart, we
603 * list delegation in the server from the delegations
604 * of that inode.
605 * prev is an RCU-protected pointer to a delegation which
606 * wasn't marked for return and might be a good choice for
607 * the next place_holder.
608 */
609 prev = NULL;
610 delegation = NULL;
611 rcu_read_lock();
612 if (place_holder)
613 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
614 if (!delegation || delegation != place_holder_deleg)
615 delegation = list_entry_rcu(server->delegations.next,
616 struct nfs_delegation, super_list);
617 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
618 struct inode *to_put = NULL;
619
620 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
621 continue;
622 if (!nfs_delegation_need_return(delegation)) {
623 if (nfs4_is_valid_delegation(delegation, flags: 0))
624 prev = delegation;
625 continue;
626 }
627
628 if (prev) {
629 struct inode *tmp = nfs_delegation_grab_inode(delegation: prev);
630 if (tmp) {
631 to_put = place_holder;
632 place_holder = tmp;
633 place_holder_deleg = prev;
634 }
635 }
636
637 inode = nfs_delegation_grab_inode(delegation);
638 if (inode == NULL) {
639 rcu_read_unlock();
640 iput(to_put);
641 goto restart;
642 }
643 delegation = nfs_start_delegation_return_locked(nfsi: NFS_I(inode));
644 rcu_read_unlock();
645
646 iput(to_put);
647
648 err = nfs_end_delegation_return(inode, delegation, issync: 0);
649 iput(inode);
650 cond_resched();
651 if (!err)
652 goto restart;
653 set_bit(nr: NFS4CLNT_DELEGRETURN, addr: &server->nfs_client->cl_state);
654 goto out;
655 }
656 rcu_read_unlock();
657out:
658 iput(place_holder);
659 return err;
660}
661
662static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
663{
664 struct nfs_delegation *d;
665 bool ret = false;
666
667 list_for_each_entry_rcu (d, &server->delegations, super_list) {
668 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
669 continue;
670 nfs_mark_return_delegation(server, delegation: d);
671 clear_bit(nr: NFS_DELEGATION_RETURN_DELAYED, addr: &d->flags);
672 ret = true;
673 }
674 return ret;
675}
676
677static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
678{
679 struct nfs_server *server;
680 bool ret = false;
681
682 if (!test_and_clear_bit(nr: NFS4CLNT_DELEGRETURN_DELAYED, addr: &clp->cl_state))
683 goto out;
684 rcu_read_lock();
685 list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
686 if (nfs_server_clear_delayed_delegations(server))
687 ret = true;
688 }
689 rcu_read_unlock();
690out:
691 return ret;
692}
693
694/**
695 * nfs_client_return_marked_delegations - return previously marked delegations
696 * @clp: nfs_client to process
697 *
698 * Note that this function is designed to be called by the state
699 * manager thread. For this reason, it cannot flush the dirty data,
700 * since that could deadlock in case of a state recovery error.
701 *
702 * Returns zero on success, or a negative errno value.
703 */
704int nfs_client_return_marked_delegations(struct nfs_client *clp)
705{
706 int err = nfs_client_for_each_server(
707 clp, fn: nfs_server_return_marked_delegations, NULL);
708 if (err)
709 return err;
710 /* If a return was delayed, sleep to prevent hard looping */
711 if (nfs_client_clear_delayed_delegations(clp))
712 ssleep(seconds: 1);
713 return 0;
714}
715
716/**
717 * nfs_inode_evict_delegation - return delegation, don't reclaim opens
718 * @inode: inode to process
719 *
720 * Does not protect against delegation reclaims, therefore really only safe
721 * to be called from nfs4_clear_inode(). Guaranteed to always free
722 * the delegation structure.
723 */
724void nfs_inode_evict_delegation(struct inode *inode)
725{
726 struct nfs_delegation *delegation;
727
728 delegation = nfs_inode_detach_delegation(inode);
729 if (delegation != NULL) {
730 set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
731 set_bit(nr: NFS_DELEGATION_INODE_FREEING, addr: &delegation->flags);
732 nfs_do_return_delegation(inode, delegation, issync: 1);
733 nfs_free_delegation(delegation);
734 }
735}
736
737/**
738 * nfs4_inode_return_delegation - synchronously return a delegation
739 * @inode: inode to process
740 *
741 * This routine will always flush any dirty data to disk on the
742 * assumption that if we need to return the delegation, then
743 * we should stop caching.
744 *
745 * Returns zero on success, or a negative errno value.
746 */
747int nfs4_inode_return_delegation(struct inode *inode)
748{
749 struct nfs_inode *nfsi = NFS_I(inode);
750 struct nfs_delegation *delegation;
751
752 delegation = nfs_start_delegation_return(nfsi);
753 if (delegation != NULL) {
754 /* Synchronous recall of any application leases */
755 break_lease(inode, O_WRONLY | O_RDWR);
756 if (S_ISREG(inode->i_mode))
757 nfs_wb_all(inode);
758 return nfs_end_delegation_return(inode, delegation, issync: 1);
759 }
760 return 0;
761}
762
763/**
764 * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
765 * @inode: inode to process
766 *
767 * This routine is called on file close in order to determine if the
768 * inode delegation needs to be returned immediately.
769 */
770void nfs4_inode_return_delegation_on_close(struct inode *inode)
771{
772 struct nfs_delegation *delegation;
773 struct nfs_delegation *ret = NULL;
774
775 if (!inode)
776 return;
777 rcu_read_lock();
778 delegation = nfs4_get_valid_delegation(inode);
779 if (!delegation)
780 goto out;
781 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
782 atomic_long_read(v: &nfs_active_delegations) >= nfs_delegation_watermark) {
783 spin_lock(lock: &delegation->lock);
784 if (delegation->inode &&
785 list_empty(head: &NFS_I(inode)->open_files) &&
786 !test_and_set_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags)) {
787 clear_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
788 /* Refcount matched in nfs_end_delegation_return() */
789 ret = nfs_get_delegation(delegation);
790 }
791 spin_unlock(lock: &delegation->lock);
792 if (ret)
793 nfs_clear_verifier_delegated(inode);
794 }
795out:
796 rcu_read_unlock();
797 nfs_end_delegation_return(inode, delegation: ret, issync: 0);
798}
799
800/**
801 * nfs4_inode_make_writeable
802 * @inode: pointer to inode
803 *
804 * Make the inode writeable by returning the delegation if necessary
805 *
806 * Returns zero on success, or a negative errno value.
807 */
808int nfs4_inode_make_writeable(struct inode *inode)
809{
810 struct nfs_delegation *delegation;
811
812 rcu_read_lock();
813 delegation = nfs4_get_valid_delegation(inode);
814 if (delegation == NULL ||
815 (nfs4_has_session(clp: NFS_SERVER(inode)->nfs_client) &&
816 (delegation->type & FMODE_WRITE))) {
817 rcu_read_unlock();
818 return 0;
819 }
820 rcu_read_unlock();
821 return nfs4_inode_return_delegation(inode);
822}
823
824static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
825 struct nfs_delegation *delegation)
826{
827 set_bit(nr: NFS_DELEGATION_RETURN_IF_CLOSED, addr: &delegation->flags);
828 set_bit(nr: NFS4CLNT_DELEGRETURN, addr: &server->nfs_client->cl_state);
829}
830
831static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
832{
833 struct nfs_delegation *delegation;
834 bool ret = false;
835
836 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
837 nfs_mark_return_delegation(server, delegation);
838 ret = true;
839 }
840 return ret;
841}
842
843static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
844{
845 struct nfs_server *server;
846
847 rcu_read_lock();
848 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
849 nfs_server_mark_return_all_delegations(server);
850 rcu_read_unlock();
851}
852
853static void nfs_delegation_run_state_manager(struct nfs_client *clp)
854{
855 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
856 nfs4_schedule_state_manager(clp);
857}
858
859/**
860 * nfs_expire_all_delegations
861 * @clp: client to process
862 *
863 */
864void nfs_expire_all_delegations(struct nfs_client *clp)
865{
866 nfs_client_mark_return_all_delegations(clp);
867 nfs_delegation_run_state_manager(clp);
868}
869
870/**
871 * nfs_server_return_all_delegations - return delegations for one superblock
872 * @server: pointer to nfs_server to process
873 *
874 */
875void nfs_server_return_all_delegations(struct nfs_server *server)
876{
877 struct nfs_client *clp = server->nfs_client;
878 bool need_wait;
879
880 if (clp == NULL)
881 return;
882
883 rcu_read_lock();
884 need_wait = nfs_server_mark_return_all_delegations(server);
885 rcu_read_unlock();
886
887 if (need_wait) {
888 nfs4_schedule_state_manager(clp);
889 nfs4_wait_clnt_recover(clp);
890 }
891}
892
893static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
894 fmode_t flags)
895{
896 struct nfs_delegation *delegation;
897
898 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
899 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
900 continue;
901 if (delegation->type & flags)
902 nfs_mark_return_if_closed_delegation(server, delegation);
903 }
904}
905
906static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
907 fmode_t flags)
908{
909 struct nfs_server *server;
910
911 rcu_read_lock();
912 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
913 nfs_mark_return_unused_delegation_types(server, flags);
914 rcu_read_unlock();
915}
916
917static void nfs_revoke_delegation(struct inode *inode,
918 const nfs4_stateid *stateid)
919{
920 struct nfs_delegation *delegation;
921 nfs4_stateid tmp;
922 bool ret = false;
923
924 rcu_read_lock();
925 delegation = rcu_dereference(NFS_I(inode)->delegation);
926 if (delegation == NULL)
927 goto out;
928 if (stateid == NULL) {
929 nfs4_stateid_copy(dst: &tmp, src: &delegation->stateid);
930 stateid = &tmp;
931 } else {
932 if (!nfs4_stateid_match_other(dst: stateid, src: &delegation->stateid))
933 goto out;
934 spin_lock(lock: &delegation->lock);
935 if (stateid->seqid) {
936 if (nfs4_stateid_is_newer(s1: &delegation->stateid, s2: stateid)) {
937 spin_unlock(lock: &delegation->lock);
938 goto out;
939 }
940 delegation->stateid.seqid = stateid->seqid;
941 }
942 spin_unlock(lock: &delegation->lock);
943 }
944 nfs_mark_delegation_revoked(delegation);
945 ret = true;
946out:
947 rcu_read_unlock();
948 if (ret)
949 nfs_inode_find_state_and_recover(inode, stateid);
950}
951
952void nfs_remove_bad_delegation(struct inode *inode,
953 const nfs4_stateid *stateid)
954{
955 nfs_revoke_delegation(inode, stateid);
956}
957EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
958
959void nfs_delegation_mark_returned(struct inode *inode,
960 const nfs4_stateid *stateid)
961{
962 struct nfs_delegation *delegation;
963
964 if (!inode)
965 return;
966
967 rcu_read_lock();
968 delegation = rcu_dereference(NFS_I(inode)->delegation);
969 if (!delegation)
970 goto out_rcu_unlock;
971
972 spin_lock(lock: &delegation->lock);
973 if (!nfs4_stateid_match_other(dst: stateid, src: &delegation->stateid))
974 goto out_spin_unlock;
975 if (stateid->seqid) {
976 /* If delegation->stateid is newer, dont mark as returned */
977 if (nfs4_stateid_is_newer(s1: &delegation->stateid, s2: stateid))
978 goto out_clear_returning;
979 if (delegation->stateid.seqid != stateid->seqid)
980 delegation->stateid.seqid = stateid->seqid;
981 }
982
983 nfs_mark_delegation_revoked(delegation);
984
985out_clear_returning:
986 clear_bit(nr: NFS_DELEGATION_RETURNING, addr: &delegation->flags);
987out_spin_unlock:
988 spin_unlock(lock: &delegation->lock);
989out_rcu_unlock:
990 rcu_read_unlock();
991
992 nfs_inode_find_state_and_recover(inode, stateid);
993}
994
995/**
996 * nfs_expire_unused_delegation_types
997 * @clp: client to process
998 * @flags: delegation types to expire
999 *
1000 */
1001void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1002{
1003 nfs_client_mark_return_unused_delegation_types(clp, flags);
1004 nfs_delegation_run_state_manager(clp);
1005}
1006
1007static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1008{
1009 struct nfs_delegation *delegation;
1010
1011 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1012 if (test_and_clear_bit(nr: NFS_DELEGATION_REFERENCED, addr: &delegation->flags))
1013 continue;
1014 nfs_mark_return_if_closed_delegation(server, delegation);
1015 }
1016}
1017
1018/**
1019 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1020 * @clp: nfs_client to process
1021 *
1022 */
1023void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
1024{
1025 struct nfs_server *server;
1026
1027 rcu_read_lock();
1028 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1029 nfs_mark_return_unreferenced_delegations(server);
1030 rcu_read_unlock();
1031
1032 nfs_delegation_run_state_manager(clp);
1033}
1034
1035/**
1036 * nfs_async_inode_return_delegation - asynchronously return a delegation
1037 * @inode: inode to process
1038 * @stateid: state ID information
1039 *
1040 * Returns zero on success, or a negative errno value.
1041 */
1042int nfs_async_inode_return_delegation(struct inode *inode,
1043 const nfs4_stateid *stateid)
1044{
1045 struct nfs_server *server = NFS_SERVER(inode);
1046 struct nfs_client *clp = server->nfs_client;
1047 struct nfs_delegation *delegation;
1048
1049 rcu_read_lock();
1050 delegation = nfs4_get_valid_delegation(inode);
1051 if (delegation == NULL)
1052 goto out_enoent;
1053 if (stateid != NULL &&
1054 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1055 goto out_enoent;
1056 nfs_mark_return_delegation(server, delegation);
1057 rcu_read_unlock();
1058
1059 /* If there are any application leases or delegations, recall them */
1060 break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1061
1062 nfs_delegation_run_state_manager(clp);
1063 return 0;
1064out_enoent:
1065 rcu_read_unlock();
1066 return -ENOENT;
1067}
1068
1069static struct inode *
1070nfs_delegation_find_inode_server(struct nfs_server *server,
1071 const struct nfs_fh *fhandle)
1072{
1073 struct nfs_delegation *delegation;
1074 struct super_block *freeme = NULL;
1075 struct inode *res = NULL;
1076
1077 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1078 spin_lock(lock: &delegation->lock);
1079 if (delegation->inode != NULL &&
1080 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1081 nfs_compare_fh(a: fhandle, b: &NFS_I(inode: delegation->inode)->fh) == 0) {
1082 if (nfs_sb_active(sb: server->super)) {
1083 freeme = server->super;
1084 res = igrab(delegation->inode);
1085 }
1086 spin_unlock(lock: &delegation->lock);
1087 if (res != NULL)
1088 return res;
1089 if (freeme) {
1090 rcu_read_unlock();
1091 nfs_sb_deactive(sb: freeme);
1092 rcu_read_lock();
1093 }
1094 return ERR_PTR(error: -EAGAIN);
1095 }
1096 spin_unlock(lock: &delegation->lock);
1097 }
1098 return ERR_PTR(error: -ENOENT);
1099}
1100
1101/**
1102 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1103 * @clp: client state handle
1104 * @fhandle: filehandle from a delegation recall
1105 *
1106 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1107 * cannot be found.
1108 */
1109struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1110 const struct nfs_fh *fhandle)
1111{
1112 struct nfs_server *server;
1113 struct inode *res;
1114
1115 rcu_read_lock();
1116 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1117 res = nfs_delegation_find_inode_server(server, fhandle);
1118 if (res != ERR_PTR(error: -ENOENT)) {
1119 rcu_read_unlock();
1120 return res;
1121 }
1122 }
1123 rcu_read_unlock();
1124 return ERR_PTR(error: -ENOENT);
1125}
1126
1127static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1128{
1129 struct nfs_delegation *delegation;
1130
1131 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1132 /*
1133 * If the delegation may have been admin revoked, then we
1134 * cannot reclaim it.
1135 */
1136 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1137 continue;
1138 set_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
1139 }
1140}
1141
1142/**
1143 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1144 * @clp: nfs_client to process
1145 *
1146 */
1147void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1148{
1149 struct nfs_server *server;
1150
1151 rcu_read_lock();
1152 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1153 nfs_delegation_mark_reclaim_server(server);
1154 rcu_read_unlock();
1155}
1156
1157static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1158 void __always_unused *data)
1159{
1160 struct nfs_delegation *delegation;
1161 struct inode *inode;
1162restart:
1163 rcu_read_lock();
1164restart_locked:
1165 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1166 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1167 &delegation->flags) ||
1168 test_bit(NFS_DELEGATION_RETURNING,
1169 &delegation->flags) ||
1170 test_bit(NFS_DELEGATION_NEED_RECLAIM,
1171 &delegation->flags) == 0)
1172 continue;
1173 inode = nfs_delegation_grab_inode(delegation);
1174 if (inode == NULL)
1175 goto restart_locked;
1176 delegation = nfs_start_delegation_return_locked(nfsi: NFS_I(inode));
1177 rcu_read_unlock();
1178 if (delegation != NULL) {
1179 if (nfs_detach_delegation(nfsi: NFS_I(inode), delegation,
1180 server) != NULL)
1181 nfs_free_delegation(delegation);
1182 /* Match nfs_start_delegation_return_locked */
1183 nfs_put_delegation(delegation);
1184 }
1185 iput(inode);
1186 cond_resched();
1187 goto restart;
1188 }
1189 rcu_read_unlock();
1190 return 0;
1191}
1192
1193/**
1194 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1195 * @clp: nfs_client to process
1196 *
1197 */
1198void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1199{
1200 nfs_client_for_each_server(clp, fn: nfs_server_reap_unclaimed_delegations,
1201 NULL);
1202}
1203
1204static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1205{
1206 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1207 BIT(NFS4CLNT_LEASE_EXPIRED) |
1208 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1209}
1210
1211static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1212 struct nfs_delegation *delegation)
1213{
1214 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1215 return;
1216 clear_bit(nr: NFS_DELEGATION_NEED_RECLAIM, addr: &delegation->flags);
1217 set_bit(nr: NFS_DELEGATION_TEST_EXPIRED, addr: &delegation->flags);
1218 set_bit(nr: NFS4CLNT_DELEGATION_EXPIRED, addr: &server->nfs_client->cl_state);
1219}
1220
1221static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1222 struct inode *inode)
1223{
1224 struct nfs_delegation *delegation;
1225
1226 rcu_read_lock();
1227 delegation = rcu_dereference(NFS_I(inode)->delegation);
1228 if (delegation)
1229 nfs_mark_test_expired_delegation(server, delegation);
1230 rcu_read_unlock();
1231
1232}
1233
1234static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1235{
1236 struct nfs_delegation *delegation;
1237
1238 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1239 nfs_mark_test_expired_delegation(server, delegation);
1240}
1241
1242/**
1243 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1244 * @clp: nfs_client to process
1245 *
1246 * Iterates through all the delegations associated with this server and
1247 * marks them as needing to be checked for validity.
1248 */
1249void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1250{
1251 struct nfs_server *server;
1252
1253 rcu_read_lock();
1254 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1255 nfs_delegation_mark_test_expired_server(server);
1256 rcu_read_unlock();
1257}
1258
1259/**
1260 * nfs_test_expired_all_delegations - test all delegations for a client
1261 * @clp: nfs_client to process
1262 *
1263 * Helper for handling "recallable state revoked" status from server.
1264 */
1265void nfs_test_expired_all_delegations(struct nfs_client *clp)
1266{
1267 nfs_mark_test_expired_all_delegations(clp);
1268 nfs4_schedule_state_manager(clp);
1269}
1270
1271static void
1272nfs_delegation_test_free_expired(struct inode *inode,
1273 nfs4_stateid *stateid,
1274 const struct cred *cred)
1275{
1276 struct nfs_server *server = NFS_SERVER(inode);
1277 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1278 int status;
1279
1280 if (!cred)
1281 return;
1282 status = ops->test_and_free_expired(server, stateid, cred);
1283 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1284 nfs_remove_bad_delegation(inode, stateid);
1285}
1286
1287static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1288 void __always_unused *data)
1289{
1290 struct nfs_delegation *delegation;
1291 struct inode *inode;
1292 const struct cred *cred;
1293 nfs4_stateid stateid;
1294 unsigned long gen = ++server->delegation_gen;
1295
1296restart:
1297 rcu_read_lock();
1298restart_locked:
1299 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1300 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1301 &delegation->flags) ||
1302 test_bit(NFS_DELEGATION_RETURNING,
1303 &delegation->flags) ||
1304 test_bit(NFS_DELEGATION_TEST_EXPIRED,
1305 &delegation->flags) == 0 ||
1306 delegation->test_gen == gen)
1307 continue;
1308 inode = nfs_delegation_grab_inode(delegation);
1309 if (inode == NULL)
1310 goto restart_locked;
1311 spin_lock(lock: &delegation->lock);
1312 cred = get_cred_rcu(cred: delegation->cred);
1313 nfs4_stateid_copy(dst: &stateid, src: &delegation->stateid);
1314 spin_unlock(lock: &delegation->lock);
1315 delegation->test_gen = gen;
1316 clear_bit(nr: NFS_DELEGATION_TEST_EXPIRED, addr: &delegation->flags);
1317 rcu_read_unlock();
1318 nfs_delegation_test_free_expired(inode, stateid: &stateid, cred);
1319 put_cred(cred);
1320 if (!nfs4_server_rebooted(clp: server->nfs_client)) {
1321 iput(inode);
1322 cond_resched();
1323 goto restart;
1324 }
1325 nfs_inode_mark_test_expired_delegation(server,inode);
1326 iput(inode);
1327 return -EAGAIN;
1328 }
1329 rcu_read_unlock();
1330 return 0;
1331}
1332
1333/**
1334 * nfs_reap_expired_delegations - reap expired delegations
1335 * @clp: nfs_client to process
1336 *
1337 * Iterates through all the delegations associated with this server and
1338 * checks if they have may have been revoked. This function is usually
1339 * expected to be called in cases where the server may have lost its
1340 * lease.
1341 */
1342void nfs_reap_expired_delegations(struct nfs_client *clp)
1343{
1344 nfs_client_for_each_server(clp, fn: nfs_server_reap_expired_delegations,
1345 NULL);
1346}
1347
1348void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1349 const nfs4_stateid *stateid)
1350{
1351 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1352 struct nfs_delegation *delegation;
1353 bool found = false;
1354
1355 rcu_read_lock();
1356 delegation = rcu_dereference(NFS_I(inode)->delegation);
1357 if (delegation &&
1358 nfs4_stateid_match_or_older(dst: &delegation->stateid, src: stateid) &&
1359 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1360 nfs_mark_test_expired_delegation(server: NFS_SERVER(inode), delegation);
1361 found = true;
1362 }
1363 rcu_read_unlock();
1364 if (found)
1365 nfs4_schedule_state_manager(clp);
1366}
1367
1368/**
1369 * nfs_delegations_present - check for existence of delegations
1370 * @clp: client state handle
1371 *
1372 * Returns one if there are any nfs_delegation structures attached
1373 * to this nfs_client.
1374 */
1375int nfs_delegations_present(struct nfs_client *clp)
1376{
1377 struct nfs_server *server;
1378 int ret = 0;
1379
1380 rcu_read_lock();
1381 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1382 if (!list_empty(head: &server->delegations)) {
1383 ret = 1;
1384 break;
1385 }
1386 rcu_read_unlock();
1387 return ret;
1388}
1389
1390/**
1391 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1392 * @dst: stateid to refresh
1393 * @inode: inode to check
1394 *
1395 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1396 * that matches our delegation stateid. Otherwise "false" is returned.
1397 */
1398bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1399{
1400 struct nfs_delegation *delegation;
1401 bool ret = false;
1402 if (!inode)
1403 goto out;
1404
1405 rcu_read_lock();
1406 delegation = rcu_dereference(NFS_I(inode)->delegation);
1407 if (delegation != NULL &&
1408 nfs4_stateid_match_other(dst, src: &delegation->stateid) &&
1409 nfs4_stateid_is_newer(s1: &delegation->stateid, s2: dst) &&
1410 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1411 dst->seqid = delegation->stateid.seqid;
1412 ret = true;
1413 }
1414 rcu_read_unlock();
1415out:
1416 return ret;
1417}
1418
1419/**
1420 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1421 * @inode: inode to check
1422 * @flags: delegation type requirement
1423 * @dst: stateid data structure to fill in
1424 * @cred: optional argument to retrieve credential
1425 *
1426 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1427 * otherwise "false" is returned.
1428 */
1429bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1430 nfs4_stateid *dst, const struct cred **cred)
1431{
1432 struct nfs_inode *nfsi = NFS_I(inode);
1433 struct nfs_delegation *delegation;
1434 bool ret = false;
1435
1436 flags &= FMODE_READ|FMODE_WRITE;
1437 rcu_read_lock();
1438 delegation = rcu_dereference(nfsi->delegation);
1439 if (!delegation)
1440 goto out;
1441 spin_lock(lock: &delegation->lock);
1442 ret = nfs4_is_valid_delegation(delegation, flags);
1443 if (ret) {
1444 nfs4_stateid_copy(dst, src: &delegation->stateid);
1445 nfs_mark_delegation_referenced(delegation);
1446 if (cred)
1447 *cred = get_cred(cred: delegation->cred);
1448 }
1449 spin_unlock(lock: &delegation->lock);
1450out:
1451 rcu_read_unlock();
1452 return ret;
1453}
1454
1455/**
1456 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1457 * @inode: inode to check
1458 *
1459 * This function checks the number of outstanding writes to the file
1460 * against the delegation 'space_limit' field to see if
1461 * the spec requires us to flush the file on close.
1462 */
1463bool nfs4_delegation_flush_on_close(const struct inode *inode)
1464{
1465 struct nfs_inode *nfsi = NFS_I(inode);
1466 struct nfs_delegation *delegation;
1467 bool ret = true;
1468
1469 rcu_read_lock();
1470 delegation = rcu_dereference(nfsi->delegation);
1471 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1472 goto out;
1473 if (atomic_long_read(v: &nfsi->nrequests) < delegation->pagemod_limit)
1474 ret = false;
1475out:
1476 rcu_read_unlock();
1477 return ret;
1478}
1479
1480module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
1481

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