ead8a0e06abf9abdc179601f61ee3a3fe2c4736c
[releases.git] / delegation.c
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
30 static atomic_long_t nfs_active_delegations;
31 static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
32
33 static 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
40 static 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
50 static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
51 {
52         refcount_inc(&delegation->refcount);
53         return delegation;
54 }
55
56 static void nfs_put_delegation(struct nfs_delegation *delegation)
57 {
58         if (refcount_dec_and_test(&delegation->refcount))
59                 __nfs_free_delegation(delegation);
60 }
61
62 static 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  */
73 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
74 {
75         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
76 }
77
78 static 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
85 static bool
86 nfs4_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
96 struct 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
106 static int
107 nfs4_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  */
131 int 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  */
140 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
141 {
142         return nfs4_do_check_delegation(inode, flags, false);
143 }
144
145 static 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 = inode->i_flctx;
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);
158 restart:
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);
173 out:
174         return status;
175 }
176
177 static 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
187 again:
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  */
230 void 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
261 static 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
278 static 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
291 static struct nfs_delegation *
292 nfs_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);
308 out:
309         return ret;
310 }
311
312 static struct nfs_delegation *
313 nfs_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
323 static 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
336 static struct nfs_delegation *
337 nfs_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
360 static 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
372 static struct nfs_delegation *
373 nfs_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
387 static void
388 nfs_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
399 static void
400 nfs_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  */
428 int 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;
490 add_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);
514 out:
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  */
528 static 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);
561 out:
562         /* Refcount matched in nfs_start_delegation_return_locked() */
563         nfs_put_delegation(delegation);
564         return err;
565 }
566
567 static 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
592 static 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
602 restart:
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();
660 out:
661         iput(place_holder);
662         return err;
663 }
664
665 static 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
680 static 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();
693 out:
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  */
707 int 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  */
727 void 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  */
750 int 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  */
773 void 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         }
798 out:
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  */
811 int 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
827 static 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
834 static 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
846 static 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
856 static 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  */
867 void 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  */
878 void 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
896 static 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
909 static 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
920 static 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;
949 out:
950         rcu_read_unlock();
951         if (ret)
952                 nfs_inode_find_state_and_recover(inode, stateid);
953 }
954
955 void nfs_remove_bad_delegation(struct inode *inode,
956                 const nfs4_stateid *stateid)
957 {
958         nfs_revoke_delegation(inode, stateid);
959 }
960 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
961
962 void 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
988 out_clear_returning:
989         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
990 out_spin_unlock:
991         spin_unlock(&delegation->lock);
992 out_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  */
1004 void 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
1010 static 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  */
1026 void 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  */
1045 int 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;
1067 out_enoent:
1068         rcu_read_unlock();
1069         return -ENOENT;
1070 }
1071
1072 static struct inode *
1073 nfs_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  */
1112 struct 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
1130 static 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  */
1150 void 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
1160 static 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;
1165 restart:
1166         rcu_read_lock();
1167 restart_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  */
1201 void 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
1207 static 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
1214 static 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
1224 static 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
1237 static 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  */
1252 void 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  */
1268 void 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
1274 static void
1275 nfs_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
1290 static 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;
1297 restart:
1298         rcu_read_lock();
1299 restart_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  */
1341 void 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
1347 void 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  */
1374 int 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  */
1397 bool 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();
1414 out:
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  */
1428 bool 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);
1449 out:
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  */
1462 bool 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;
1474 out:
1475         rcu_read_unlock();
1476         return ret;
1477 }
1478
1479 module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);