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1/*
2 * linux/fs/nfs/delegation.c
3 *
4 * Copyright (C) 2004 Trond Myklebust
5 *
6 * NFS file delegation management
7 *
8 */
9#include <linux/completion.h>
10#include <linux/kthread.h>
11#include <linux/module.h>
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/iversion.h>
16
17#include <linux/nfs4.h>
18#include <linux/nfs_fs.h>
19#include <linux/nfs_xdr.h>
20
21#include "nfs4_fs.h"
22#include "nfs4session.h"
23#include "delegation.h"
24#include "internal.h"
25#include "nfs4trace.h"
26
27static void nfs_free_delegation(struct nfs_delegation *delegation)
28{
29 if (delegation->cred) {
30 put_rpccred(delegation->cred);
31 delegation->cred = NULL;
32 }
33 kfree_rcu(delegation, rcu);
34}
35
36/**
37 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
38 * @delegation: delegation to process
39 *
40 */
41void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
42{
43 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
44}
45
46static bool
47nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
48 fmode_t flags)
49{
50 if (delegation != NULL && (delegation->type & flags) == flags &&
51 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
52 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
53 return true;
54 return false;
55}
56
57static int
58nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
59{
60 struct nfs_delegation *delegation;
61 int ret = 0;
62
63 flags &= FMODE_READ|FMODE_WRITE;
64 rcu_read_lock();
65 delegation = rcu_dereference(NFS_I(inode)->delegation);
66 if (nfs4_is_valid_delegation(delegation, flags)) {
67 if (mark)
68 nfs_mark_delegation_referenced(delegation);
69 ret = 1;
70 }
71 rcu_read_unlock();
72 return ret;
73}
74/**
75 * nfs_have_delegation - check if inode has a delegation, mark it
76 * NFS_DELEGATION_REFERENCED if there is one.
77 * @inode: inode to check
78 * @flags: delegation types to check for
79 *
80 * Returns one if inode has the indicated delegation, otherwise zero.
81 */
82int nfs4_have_delegation(struct inode *inode, fmode_t flags)
83{
84 return nfs4_do_check_delegation(inode, flags, true);
85}
86
87/*
88 * nfs4_check_delegation - check if inode has a delegation, do not mark
89 * NFS_DELEGATION_REFERENCED if it has one.
90 */
91int nfs4_check_delegation(struct inode *inode, fmode_t flags)
92{
93 return nfs4_do_check_delegation(inode, flags, false);
94}
95
96static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
97{
98 struct inode *inode = state->inode;
99 struct file_lock *fl;
100 struct file_lock_context *flctx = inode->i_flctx;
101 struct list_head *list;
102 int status = 0;
103
104 if (flctx == NULL)
105 goto out;
106
107 list = &flctx->flc_posix;
108 spin_lock(&flctx->flc_lock);
109restart:
110 list_for_each_entry(fl, list, fl_list) {
111 if (nfs_file_open_context(fl->fl_file) != ctx)
112 continue;
113 spin_unlock(&flctx->flc_lock);
114 status = nfs4_lock_delegation_recall(fl, state, stateid);
115 if (status < 0)
116 goto out;
117 spin_lock(&flctx->flc_lock);
118 }
119 if (list == &flctx->flc_posix) {
120 list = &flctx->flc_flock;
121 goto restart;
122 }
123 spin_unlock(&flctx->flc_lock);
124out:
125 return status;
126}
127
128static int nfs_delegation_claim_opens(struct inode *inode,
129 const nfs4_stateid *stateid, fmode_t type)
130{
131 struct nfs_inode *nfsi = NFS_I(inode);
132 struct nfs_open_context *ctx;
133 struct nfs4_state_owner *sp;
134 struct nfs4_state *state;
135 unsigned int seq;
136 int err;
137
138again:
139 spin_lock(&inode->i_lock);
140 list_for_each_entry(ctx, &nfsi->open_files, list) {
141 state = ctx->state;
142 if (state == NULL)
143 continue;
144 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
145 continue;
146 if (!nfs4_valid_open_stateid(state))
147 continue;
148 if (!nfs4_stateid_match(&state->stateid, stateid))
149 continue;
150 get_nfs_open_context(ctx);
151 spin_unlock(&inode->i_lock);
152 sp = state->owner;
153 /* Block nfs4_proc_unlck */
154 mutex_lock(&sp->so_delegreturn_mutex);
155 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
156 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
157 if (!err)
158 err = nfs_delegation_claim_locks(ctx, state, stateid);
159 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
160 err = -EAGAIN;
161 mutex_unlock(&sp->so_delegreturn_mutex);
162 put_nfs_open_context(ctx);
163 if (err != 0)
164 return err;
165 goto again;
166 }
167 spin_unlock(&inode->i_lock);
168 return 0;
169}
170
171/**
172 * nfs_inode_reclaim_delegation - process a delegation reclaim request
173 * @inode: inode to process
174 * @cred: credential to use for request
175 * @type: delegation type
176 * @stateid: delegation stateid
177 * @pagemod_limit: write delegation "space_limit"
178 *
179 */
180void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
181 fmode_t type,
182 const nfs4_stateid *stateid,
183 unsigned long pagemod_limit)
184{
185 struct nfs_delegation *delegation;
186 struct rpc_cred *oldcred = NULL;
187
188 rcu_read_lock();
189 delegation = rcu_dereference(NFS_I(inode)->delegation);
190 if (delegation != NULL) {
191 spin_lock(&delegation->lock);
192 if (delegation->inode != NULL) {
193 nfs4_stateid_copy(&delegation->stateid, stateid);
194 delegation->type = type;
195 delegation->pagemod_limit = pagemod_limit;
196 oldcred = delegation->cred;
197 delegation->cred = get_rpccred(cred);
198 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
199 &delegation->flags);
200 spin_unlock(&delegation->lock);
201 rcu_read_unlock();
202 put_rpccred(oldcred);
203 trace_nfs4_reclaim_delegation(inode, type);
204 return;
205 }
206 /* We appear to have raced with a delegation return. */
207 spin_unlock(&delegation->lock);
208 }
209 rcu_read_unlock();
210 nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
211}
212
213static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
214{
215 int res = 0;
216
217 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
218 res = nfs4_proc_delegreturn(inode,
219 delegation->cred,
220 &delegation->stateid,
221 issync);
222 nfs_free_delegation(delegation);
223 return res;
224}
225
226static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
227{
228 struct inode *inode = NULL;
229
230 spin_lock(&delegation->lock);
231 if (delegation->inode != NULL)
232 inode = igrab(delegation->inode);
233 spin_unlock(&delegation->lock);
234 return inode;
235}
236
237static struct nfs_delegation *
238nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
239{
240 struct nfs_delegation *ret = NULL;
241 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
242
243 if (delegation == NULL)
244 goto out;
245 spin_lock(&delegation->lock);
246 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
247 ret = delegation;
248 spin_unlock(&delegation->lock);
249out:
250 return ret;
251}
252
253static struct nfs_delegation *
254nfs_start_delegation_return(struct nfs_inode *nfsi)
255{
256 struct nfs_delegation *delegation;
257
258 rcu_read_lock();
259 delegation = nfs_start_delegation_return_locked(nfsi);
260 rcu_read_unlock();
261 return delegation;
262}
263
264static void
265nfs_abort_delegation_return(struct nfs_delegation *delegation,
266 struct nfs_client *clp)
267{
268
269 spin_lock(&delegation->lock);
270 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
271 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
272 spin_unlock(&delegation->lock);
273 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
274}
275
276static struct nfs_delegation *
277nfs_detach_delegation_locked(struct nfs_inode *nfsi,
278 struct nfs_delegation *delegation,
279 struct nfs_client *clp)
280{
281 struct nfs_delegation *deleg_cur =
282 rcu_dereference_protected(nfsi->delegation,
283 lockdep_is_held(&clp->cl_lock));
284
285 if (deleg_cur == NULL || delegation != deleg_cur)
286 return NULL;
287
288 spin_lock(&delegation->lock);
289 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
290 list_del_rcu(&delegation->super_list);
291 delegation->inode = NULL;
292 rcu_assign_pointer(nfsi->delegation, NULL);
293 spin_unlock(&delegation->lock);
294 return delegation;
295}
296
297static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
298 struct nfs_delegation *delegation,
299 struct nfs_server *server)
300{
301 struct nfs_client *clp = server->nfs_client;
302
303 spin_lock(&clp->cl_lock);
304 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
305 spin_unlock(&clp->cl_lock);
306 return delegation;
307}
308
309static struct nfs_delegation *
310nfs_inode_detach_delegation(struct inode *inode)
311{
312 struct nfs_inode *nfsi = NFS_I(inode);
313 struct nfs_server *server = NFS_SERVER(inode);
314 struct nfs_delegation *delegation;
315
316 delegation = nfs_start_delegation_return(nfsi);
317 if (delegation == NULL)
318 return NULL;
319 return nfs_detach_delegation(nfsi, delegation, server);
320}
321
322static void
323nfs_update_inplace_delegation(struct nfs_delegation *delegation,
324 const struct nfs_delegation *update)
325{
326 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
327 delegation->stateid.seqid = update->stateid.seqid;
328 smp_wmb();
329 delegation->type = update->type;
330 }
331}
332
333/**
334 * nfs_inode_set_delegation - set up a delegation on an inode
335 * @inode: inode to which delegation applies
336 * @cred: cred to use for subsequent delegation processing
337 * @type: delegation type
338 * @stateid: delegation stateid
339 * @pagemod_limit: write delegation "space_limit"
340 *
341 * Returns zero on success, or a negative errno value.
342 */
343int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred,
344 fmode_t type,
345 const nfs4_stateid *stateid,
346 unsigned long pagemod_limit)
347{
348 struct nfs_server *server = NFS_SERVER(inode);
349 struct nfs_client *clp = server->nfs_client;
350 struct nfs_inode *nfsi = NFS_I(inode);
351 struct nfs_delegation *delegation, *old_delegation;
352 struct nfs_delegation *freeme = NULL;
353 int status = 0;
354
355 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
356 if (delegation == NULL)
357 return -ENOMEM;
358 nfs4_stateid_copy(&delegation->stateid, stateid);
359 delegation->type = type;
360 delegation->pagemod_limit = pagemod_limit;
361 delegation->change_attr = inode_peek_iversion_raw(inode);
362 delegation->cred = get_rpccred(cred);
363 delegation->inode = inode;
364 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
365 spin_lock_init(&delegation->lock);
366
367 spin_lock(&clp->cl_lock);
368 old_delegation = rcu_dereference_protected(nfsi->delegation,
369 lockdep_is_held(&clp->cl_lock));
370 if (old_delegation != NULL) {
371 /* Is this an update of the existing delegation? */
372 if (nfs4_stateid_match_other(&old_delegation->stateid,
373 &delegation->stateid)) {
374 nfs_update_inplace_delegation(old_delegation,
375 delegation);
376 goto out;
377 }
378 /*
379 * Deal with broken servers that hand out two
380 * delegations for the same file.
381 * Allow for upgrades to a WRITE delegation, but
382 * nothing else.
383 */
384 dfprintk(FILE, "%s: server %s handed out "
385 "a duplicate delegation!\n",
386 __func__, clp->cl_hostname);
387 if (delegation->type == old_delegation->type ||
388 !(delegation->type & FMODE_WRITE)) {
389 freeme = delegation;
390 delegation = NULL;
391 goto out;
392 }
393 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
394 &old_delegation->flags))
395 goto out;
396 freeme = nfs_detach_delegation_locked(nfsi,
397 old_delegation, clp);
398 if (freeme == NULL)
399 goto out;
400 }
401 list_add_tail_rcu(&delegation->super_list, &server->delegations);
402 rcu_assign_pointer(nfsi->delegation, delegation);
403 delegation = NULL;
404
405 trace_nfs4_set_delegation(inode, type);
406
407out:
408 spin_unlock(&clp->cl_lock);
409 if (delegation != NULL)
410 nfs_free_delegation(delegation);
411 if (freeme != NULL)
412 nfs_do_return_delegation(inode, freeme, 0);
413 return status;
414}
415
416/*
417 * Basic procedure for returning a delegation to the server
418 */
419static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
420{
421 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
422 struct nfs_inode *nfsi = NFS_I(inode);
423 int err = 0;
424
425 if (delegation == NULL)
426 return 0;
427 do {
428 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
429 break;
430 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
431 delegation->type);
432 if (!issync || err != -EAGAIN)
433 break;
434 /*
435 * Guard against state recovery
436 */
437 err = nfs4_wait_clnt_recover(clp);
438 } while (err == 0);
439
440 if (err) {
441 nfs_abort_delegation_return(delegation, clp);
442 goto out;
443 }
444 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
445 goto out;
446
447 err = nfs_do_return_delegation(inode, delegation, issync);
448out:
449 return err;
450}
451
452static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
453{
454 bool ret = false;
455
456 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
457 goto out;
458 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
459 ret = true;
460 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
461 struct inode *inode;
462
463 spin_lock(&delegation->lock);
464 inode = delegation->inode;
465 if (inode && list_empty(&NFS_I(inode)->open_files))
466 ret = true;
467 spin_unlock(&delegation->lock);
468 }
469out:
470 return ret;
471}
472
473/**
474 * nfs_client_return_marked_delegations - return previously marked delegations
475 * @clp: nfs_client to process
476 *
477 * Note that this function is designed to be called by the state
478 * manager thread. For this reason, it cannot flush the dirty data,
479 * since that could deadlock in case of a state recovery error.
480 *
481 * Returns zero on success, or a negative errno value.
482 */
483int nfs_client_return_marked_delegations(struct nfs_client *clp)
484{
485 struct nfs_delegation *delegation;
486 struct nfs_server *server;
487 struct inode *inode;
488 int err = 0;
489
490restart:
491 rcu_read_lock();
492 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
493 list_for_each_entry_rcu(delegation, &server->delegations,
494 super_list) {
495 if (!nfs_delegation_need_return(delegation))
496 continue;
497 if (!nfs_sb_active(server->super))
498 continue;
499 inode = nfs_delegation_grab_inode(delegation);
500 if (inode == NULL) {
501 rcu_read_unlock();
502 nfs_sb_deactive(server->super);
503 goto restart;
504 }
505 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
506 rcu_read_unlock();
507
508 err = nfs_end_delegation_return(inode, delegation, 0);
509 iput(inode);
510 nfs_sb_deactive(server->super);
511 if (!err)
512 goto restart;
513 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
514 return err;
515 }
516 }
517 rcu_read_unlock();
518 return 0;
519}
520
521/**
522 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
523 * @inode: inode to process
524 *
525 * Does not protect against delegation reclaims, therefore really only safe
526 * to be called from nfs4_clear_inode().
527 */
528void nfs_inode_return_delegation_noreclaim(struct inode *inode)
529{
530 struct nfs_delegation *delegation;
531
532 delegation = nfs_inode_detach_delegation(inode);
533 if (delegation != NULL)
534 nfs_do_return_delegation(inode, delegation, 1);
535}
536
537/**
538 * nfs_inode_return_delegation - synchronously return a delegation
539 * @inode: inode to process
540 *
541 * This routine will always flush any dirty data to disk on the
542 * assumption that if we need to return the delegation, then
543 * we should stop caching.
544 *
545 * Returns zero on success, or a negative errno value.
546 */
547int nfs4_inode_return_delegation(struct inode *inode)
548{
549 struct nfs_inode *nfsi = NFS_I(inode);
550 struct nfs_delegation *delegation;
551 int err = 0;
552
553 nfs_wb_all(inode);
554 delegation = nfs_start_delegation_return(nfsi);
555 if (delegation != NULL)
556 err = nfs_end_delegation_return(inode, delegation, 1);
557 return err;
558}
559
560/**
561 * nfs4_inode_make_writeable
562 * @inode: pointer to inode
563 *
564 * Make the inode writeable by returning the delegation if necessary
565 *
566 * Returns zero on success, or a negative errno value.
567 */
568int nfs4_inode_make_writeable(struct inode *inode)
569{
570 if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
571 !nfs4_check_delegation(inode, FMODE_WRITE))
572 return nfs4_inode_return_delegation(inode);
573 return 0;
574}
575
576static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
577 struct nfs_delegation *delegation)
578{
579 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
580 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
581}
582
583static void nfs_mark_return_delegation(struct nfs_server *server,
584 struct nfs_delegation *delegation)
585{
586 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
587 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
588}
589
590static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
591{
592 struct nfs_delegation *delegation;
593 bool ret = false;
594
595 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
596 nfs_mark_return_delegation(server, delegation);
597 ret = true;
598 }
599 return ret;
600}
601
602static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
603{
604 struct nfs_server *server;
605
606 rcu_read_lock();
607 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
608 nfs_server_mark_return_all_delegations(server);
609 rcu_read_unlock();
610}
611
612static void nfs_delegation_run_state_manager(struct nfs_client *clp)
613{
614 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
615 nfs4_schedule_state_manager(clp);
616}
617
618/**
619 * nfs_expire_all_delegations
620 * @clp: client to process
621 *
622 */
623void nfs_expire_all_delegations(struct nfs_client *clp)
624{
625 nfs_client_mark_return_all_delegations(clp);
626 nfs_delegation_run_state_manager(clp);
627}
628
629/**
630 * nfs_super_return_all_delegations - return delegations for one superblock
631 * @sb: sb to process
632 *
633 */
634void nfs_server_return_all_delegations(struct nfs_server *server)
635{
636 struct nfs_client *clp = server->nfs_client;
637 bool need_wait;
638
639 if (clp == NULL)
640 return;
641
642 rcu_read_lock();
643 need_wait = nfs_server_mark_return_all_delegations(server);
644 rcu_read_unlock();
645
646 if (need_wait) {
647 nfs4_schedule_state_manager(clp);
648 nfs4_wait_clnt_recover(clp);
649 }
650}
651
652static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
653 fmode_t flags)
654{
655 struct nfs_delegation *delegation;
656
657 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
658 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
659 continue;
660 if (delegation->type & flags)
661 nfs_mark_return_if_closed_delegation(server, delegation);
662 }
663}
664
665static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
666 fmode_t flags)
667{
668 struct nfs_server *server;
669
670 rcu_read_lock();
671 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
672 nfs_mark_return_unused_delegation_types(server, flags);
673 rcu_read_unlock();
674}
675
676static void nfs_mark_delegation_revoked(struct nfs_server *server,
677 struct nfs_delegation *delegation)
678{
679 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
680 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
681 nfs_mark_return_delegation(server, delegation);
682}
683
684static bool nfs_revoke_delegation(struct inode *inode,
685 const nfs4_stateid *stateid)
686{
687 struct nfs_delegation *delegation;
688 nfs4_stateid tmp;
689 bool ret = false;
690
691 rcu_read_lock();
692 delegation = rcu_dereference(NFS_I(inode)->delegation);
693 if (delegation == NULL)
694 goto out;
695 if (stateid == NULL) {
696 nfs4_stateid_copy(&tmp, &delegation->stateid);
697 stateid = &tmp;
698 } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
699 goto out;
700 nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
701 ret = true;
702out:
703 rcu_read_unlock();
704 if (ret)
705 nfs_inode_find_state_and_recover(inode, stateid);
706 return ret;
707}
708
709void nfs_remove_bad_delegation(struct inode *inode,
710 const nfs4_stateid *stateid)
711{
712 struct nfs_delegation *delegation;
713
714 if (!nfs_revoke_delegation(inode, stateid))
715 return;
716 delegation = nfs_inode_detach_delegation(inode);
717 if (delegation)
718 nfs_free_delegation(delegation);
719}
720EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
721
722/**
723 * nfs_expire_unused_delegation_types
724 * @clp: client to process
725 * @flags: delegation types to expire
726 *
727 */
728void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
729{
730 nfs_client_mark_return_unused_delegation_types(clp, flags);
731 nfs_delegation_run_state_manager(clp);
732}
733
734static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
735{
736 struct nfs_delegation *delegation;
737
738 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
739 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
740 continue;
741 nfs_mark_return_if_closed_delegation(server, delegation);
742 }
743}
744
745/**
746 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
747 * @clp: nfs_client to process
748 *
749 */
750void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
751{
752 struct nfs_server *server;
753
754 rcu_read_lock();
755 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
756 nfs_mark_return_unreferenced_delegations(server);
757 rcu_read_unlock();
758
759 nfs_delegation_run_state_manager(clp);
760}
761
762/**
763 * nfs_async_inode_return_delegation - asynchronously return a delegation
764 * @inode: inode to process
765 * @stateid: state ID information
766 *
767 * Returns zero on success, or a negative errno value.
768 */
769int nfs_async_inode_return_delegation(struct inode *inode,
770 const nfs4_stateid *stateid)
771{
772 struct nfs_server *server = NFS_SERVER(inode);
773 struct nfs_client *clp = server->nfs_client;
774 struct nfs_delegation *delegation;
775
776 rcu_read_lock();
777 delegation = rcu_dereference(NFS_I(inode)->delegation);
778 if (delegation == NULL)
779 goto out_enoent;
780 if (stateid != NULL &&
781 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
782 goto out_enoent;
783 nfs_mark_return_delegation(server, delegation);
784 rcu_read_unlock();
785
786 nfs_delegation_run_state_manager(clp);
787 return 0;
788out_enoent:
789 rcu_read_unlock();
790 return -ENOENT;
791}
792
793static struct inode *
794nfs_delegation_find_inode_server(struct nfs_server *server,
795 const struct nfs_fh *fhandle)
796{
797 struct nfs_delegation *delegation;
798 struct inode *res = NULL;
799
800 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
801 spin_lock(&delegation->lock);
802 if (delegation->inode != NULL &&
803 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
804 res = igrab(delegation->inode);
805 }
806 spin_unlock(&delegation->lock);
807 if (res != NULL)
808 break;
809 }
810 return res;
811}
812
813/**
814 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
815 * @clp: client state handle
816 * @fhandle: filehandle from a delegation recall
817 *
818 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
819 * cannot be found.
820 */
821struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
822 const struct nfs_fh *fhandle)
823{
824 struct nfs_server *server;
825 struct inode *res = NULL;
826
827 rcu_read_lock();
828 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
829 res = nfs_delegation_find_inode_server(server, fhandle);
830 if (res != NULL)
831 break;
832 }
833 rcu_read_unlock();
834 return res;
835}
836
837static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
838{
839 struct nfs_delegation *delegation;
840
841 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
842 /*
843 * If the delegation may have been admin revoked, then we
844 * cannot reclaim it.
845 */
846 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
847 continue;
848 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
849 }
850}
851
852/**
853 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
854 * @clp: nfs_client to process
855 *
856 */
857void nfs_delegation_mark_reclaim(struct nfs_client *clp)
858{
859 struct nfs_server *server;
860
861 rcu_read_lock();
862 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
863 nfs_delegation_mark_reclaim_server(server);
864 rcu_read_unlock();
865}
866
867/**
868 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
869 * @clp: nfs_client to process
870 *
871 */
872void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
873{
874 struct nfs_delegation *delegation;
875 struct nfs_server *server;
876 struct inode *inode;
877
878restart:
879 rcu_read_lock();
880 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
881 list_for_each_entry_rcu(delegation, &server->delegations,
882 super_list) {
883 if (test_bit(NFS_DELEGATION_RETURNING,
884 &delegation->flags))
885 continue;
886 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
887 &delegation->flags) == 0)
888 continue;
889 if (!nfs_sb_active(server->super))
890 continue;
891 inode = nfs_delegation_grab_inode(delegation);
892 if (inode == NULL) {
893 rcu_read_unlock();
894 nfs_sb_deactive(server->super);
895 goto restart;
896 }
897 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
898 rcu_read_unlock();
899 if (delegation != NULL) {
900 delegation = nfs_detach_delegation(NFS_I(inode),
901 delegation, server);
902 if (delegation != NULL)
903 nfs_free_delegation(delegation);
904 }
905 iput(inode);
906 nfs_sb_deactive(server->super);
907 goto restart;
908 }
909 }
910 rcu_read_unlock();
911}
912
913static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
914{
915 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
916 BIT(NFS4CLNT_LEASE_EXPIRED) |
917 BIT(NFS4CLNT_SESSION_RESET))) != 0;
918}
919
920static void nfs_mark_test_expired_delegation(struct nfs_server *server,
921 struct nfs_delegation *delegation)
922{
923 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
924 return;
925 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
926 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
927 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
928}
929
930static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
931 struct inode *inode)
932{
933 struct nfs_delegation *delegation;
934
935 rcu_read_lock();
936 delegation = rcu_dereference(NFS_I(inode)->delegation);
937 if (delegation)
938 nfs_mark_test_expired_delegation(server, delegation);
939 rcu_read_unlock();
940
941}
942
943static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
944{
945 struct nfs_delegation *delegation;
946
947 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
948 nfs_mark_test_expired_delegation(server, delegation);
949}
950
951/**
952 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
953 * @clp: nfs_client to process
954 *
955 * Iterates through all the delegations associated with this server and
956 * marks them as needing to be checked for validity.
957 */
958void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
959{
960 struct nfs_server *server;
961
962 rcu_read_lock();
963 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
964 nfs_delegation_mark_test_expired_server(server);
965 rcu_read_unlock();
966}
967
968/**
969 * nfs_reap_expired_delegations - reap expired delegations
970 * @clp: nfs_client to process
971 *
972 * Iterates through all the delegations associated with this server and
973 * checks if they have may have been revoked. This function is usually
974 * expected to be called in cases where the server may have lost its
975 * lease.
976 */
977void nfs_reap_expired_delegations(struct nfs_client *clp)
978{
979 const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
980 struct nfs_delegation *delegation;
981 struct nfs_server *server;
982 struct inode *inode;
983 struct rpc_cred *cred;
984 nfs4_stateid stateid;
985
986restart:
987 rcu_read_lock();
988 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
989 list_for_each_entry_rcu(delegation, &server->delegations,
990 super_list) {
991 if (test_bit(NFS_DELEGATION_RETURNING,
992 &delegation->flags))
993 continue;
994 if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
995 &delegation->flags) == 0)
996 continue;
997 if (!nfs_sb_active(server->super))
998 continue;
999 inode = nfs_delegation_grab_inode(delegation);
1000 if (inode == NULL) {
1001 rcu_read_unlock();
1002 nfs_sb_deactive(server->super);
1003 goto restart;
1004 }
1005 cred = get_rpccred_rcu(delegation->cred);
1006 nfs4_stateid_copy(&stateid, &delegation->stateid);
1007 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1008 rcu_read_unlock();
1009 if (cred != NULL &&
1010 ops->test_and_free_expired(server, &stateid, cred) < 0) {
1011 nfs_revoke_delegation(inode, &stateid);
1012 nfs_inode_find_state_and_recover(inode, &stateid);
1013 }
1014 put_rpccred(cred);
1015 if (nfs4_server_rebooted(clp)) {
1016 nfs_inode_mark_test_expired_delegation(server,inode);
1017 iput(inode);
1018 nfs_sb_deactive(server->super);
1019 return;
1020 }
1021 iput(inode);
1022 nfs_sb_deactive(server->super);
1023 goto restart;
1024 }
1025 }
1026 rcu_read_unlock();
1027}
1028
1029void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1030 const nfs4_stateid *stateid)
1031{
1032 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1033 struct nfs_delegation *delegation;
1034 bool found = false;
1035
1036 rcu_read_lock();
1037 delegation = rcu_dereference(NFS_I(inode)->delegation);
1038 if (delegation &&
1039 nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1040 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1041 found = true;
1042 }
1043 rcu_read_unlock();
1044 if (found)
1045 nfs4_schedule_state_manager(clp);
1046}
1047
1048/**
1049 * nfs_delegations_present - check for existence of delegations
1050 * @clp: client state handle
1051 *
1052 * Returns one if there are any nfs_delegation structures attached
1053 * to this nfs_client.
1054 */
1055int nfs_delegations_present(struct nfs_client *clp)
1056{
1057 struct nfs_server *server;
1058 int ret = 0;
1059
1060 rcu_read_lock();
1061 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1062 if (!list_empty(&server->delegations)) {
1063 ret = 1;
1064 break;
1065 }
1066 rcu_read_unlock();
1067 return ret;
1068}
1069
1070/**
1071 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1072 * @dst: stateid to refresh
1073 * @inode: inode to check
1074 *
1075 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1076 * that matches our delegation stateid. Otherwise "false" is returned.
1077 */
1078bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1079{
1080 struct nfs_delegation *delegation;
1081 bool ret = false;
1082 if (!inode)
1083 goto out;
1084
1085 rcu_read_lock();
1086 delegation = rcu_dereference(NFS_I(inode)->delegation);
1087 if (delegation != NULL &&
1088 nfs4_stateid_match_other(dst, &delegation->stateid)) {
1089 dst->seqid = delegation->stateid.seqid;
1090 return ret;
1091 }
1092 rcu_read_unlock();
1093out:
1094 return ret;
1095}
1096
1097/**
1098 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1099 * @inode: inode to check
1100 * @flags: delegation type requirement
1101 * @dst: stateid data structure to fill in
1102 * @cred: optional argument to retrieve credential
1103 *
1104 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1105 * otherwise "false" is returned.
1106 */
1107bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1108 nfs4_stateid *dst, struct rpc_cred **cred)
1109{
1110 struct nfs_inode *nfsi = NFS_I(inode);
1111 struct nfs_delegation *delegation;
1112 bool ret;
1113
1114 flags &= FMODE_READ|FMODE_WRITE;
1115 rcu_read_lock();
1116 delegation = rcu_dereference(nfsi->delegation);
1117 ret = nfs4_is_valid_delegation(delegation, flags);
1118 if (ret) {
1119 nfs4_stateid_copy(dst, &delegation->stateid);
1120 nfs_mark_delegation_referenced(delegation);
1121 if (cred)
1122 *cred = get_rpccred(delegation->cred);
1123 }
1124 rcu_read_unlock();
1125 return ret;
1126}
1127
1128/**
1129 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1130 * @inode: inode to check
1131 *
1132 * This function checks the number of outstanding writes to the file
1133 * against the delegation 'space_limit' field to see if
1134 * the spec requires us to flush the file on close.
1135 */
1136bool nfs4_delegation_flush_on_close(const struct inode *inode)
1137{
1138 struct nfs_inode *nfsi = NFS_I(inode);
1139 struct nfs_delegation *delegation;
1140 bool ret = true;
1141
1142 rcu_read_lock();
1143 delegation = rcu_dereference(nfsi->delegation);
1144 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1145 goto out;
1146 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1147 ret = false;
1148out:
1149 rcu_read_unlock();
1150 return ret;
1151}
1/*
2 * linux/fs/nfs/delegation.c
3 *
4 * Copyright (C) 2004 Trond Myklebust
5 *
6 * NFS file delegation management
7 *
8 */
9#include <linux/completion.h>
10#include <linux/kthread.h>
11#include <linux/module.h>
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15
16#include <linux/nfs4.h>
17#include <linux/nfs_fs.h>
18#include <linux/nfs_xdr.h>
19
20#include "nfs4_fs.h"
21#include "delegation.h"
22#include "internal.h"
23#include "nfs4trace.h"
24
25static void nfs_free_delegation(struct nfs_delegation *delegation)
26{
27 if (delegation->cred) {
28 put_rpccred(delegation->cred);
29 delegation->cred = NULL;
30 }
31 kfree_rcu(delegation, rcu);
32}
33
34/**
35 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
36 * @delegation: delegation to process
37 *
38 */
39void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
40{
41 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
42}
43
44static int
45nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
46{
47 struct nfs_delegation *delegation;
48 int ret = 0;
49
50 flags &= FMODE_READ|FMODE_WRITE;
51 rcu_read_lock();
52 delegation = rcu_dereference(NFS_I(inode)->delegation);
53 if (delegation != NULL && (delegation->type & flags) == flags &&
54 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
55 if (mark)
56 nfs_mark_delegation_referenced(delegation);
57 ret = 1;
58 }
59 rcu_read_unlock();
60 return ret;
61}
62/**
63 * nfs_have_delegation - check if inode has a delegation, mark it
64 * NFS_DELEGATION_REFERENCED if there is one.
65 * @inode: inode to check
66 * @flags: delegation types to check for
67 *
68 * Returns one if inode has the indicated delegation, otherwise zero.
69 */
70int nfs4_have_delegation(struct inode *inode, fmode_t flags)
71{
72 return nfs4_do_check_delegation(inode, flags, true);
73}
74
75/*
76 * nfs4_check_delegation - check if inode has a delegation, do not mark
77 * NFS_DELEGATION_REFERENCED if it has one.
78 */
79int nfs4_check_delegation(struct inode *inode, fmode_t flags)
80{
81 return nfs4_do_check_delegation(inode, flags, false);
82}
83
84static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
85{
86 struct inode *inode = state->inode;
87 struct file_lock *fl;
88 struct file_lock_context *flctx = inode->i_flctx;
89 struct list_head *list;
90 int status = 0;
91
92 if (flctx == NULL)
93 goto out;
94
95 list = &flctx->flc_posix;
96 spin_lock(&flctx->flc_lock);
97restart:
98 list_for_each_entry(fl, list, fl_list) {
99 if (nfs_file_open_context(fl->fl_file) != ctx)
100 continue;
101 spin_unlock(&flctx->flc_lock);
102 status = nfs4_lock_delegation_recall(fl, state, stateid);
103 if (status < 0)
104 goto out;
105 spin_lock(&flctx->flc_lock);
106 }
107 if (list == &flctx->flc_posix) {
108 list = &flctx->flc_flock;
109 goto restart;
110 }
111 spin_unlock(&flctx->flc_lock);
112out:
113 return status;
114}
115
116static int nfs_delegation_claim_opens(struct inode *inode,
117 const nfs4_stateid *stateid, fmode_t type)
118{
119 struct nfs_inode *nfsi = NFS_I(inode);
120 struct nfs_open_context *ctx;
121 struct nfs4_state_owner *sp;
122 struct nfs4_state *state;
123 unsigned int seq;
124 int err;
125
126again:
127 spin_lock(&inode->i_lock);
128 list_for_each_entry(ctx, &nfsi->open_files, list) {
129 state = ctx->state;
130 if (state == NULL)
131 continue;
132 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
133 continue;
134 if (!nfs4_valid_open_stateid(state))
135 continue;
136 if (!nfs4_stateid_match(&state->stateid, stateid))
137 continue;
138 get_nfs_open_context(ctx);
139 spin_unlock(&inode->i_lock);
140 sp = state->owner;
141 /* Block nfs4_proc_unlck */
142 mutex_lock(&sp->so_delegreturn_mutex);
143 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
144 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
145 if (!err)
146 err = nfs_delegation_claim_locks(ctx, state, stateid);
147 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
148 err = -EAGAIN;
149 mutex_unlock(&sp->so_delegreturn_mutex);
150 put_nfs_open_context(ctx);
151 if (err != 0)
152 return err;
153 goto again;
154 }
155 spin_unlock(&inode->i_lock);
156 return 0;
157}
158
159/**
160 * nfs_inode_reclaim_delegation - process a delegation reclaim request
161 * @inode: inode to process
162 * @cred: credential to use for request
163 * @res: new delegation state from server
164 *
165 */
166void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
167 struct nfs_openres *res)
168{
169 struct nfs_delegation *delegation;
170 struct rpc_cred *oldcred = NULL;
171
172 rcu_read_lock();
173 delegation = rcu_dereference(NFS_I(inode)->delegation);
174 if (delegation != NULL) {
175 spin_lock(&delegation->lock);
176 if (delegation->inode != NULL) {
177 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
178 delegation->type = res->delegation_type;
179 delegation->pagemod_limit = res->pagemod_limit;
180 oldcred = delegation->cred;
181 delegation->cred = get_rpccred(cred);
182 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
183 &delegation->flags);
184 spin_unlock(&delegation->lock);
185 rcu_read_unlock();
186 put_rpccred(oldcred);
187 trace_nfs4_reclaim_delegation(inode, res->delegation_type);
188 } else {
189 /* We appear to have raced with a delegation return. */
190 spin_unlock(&delegation->lock);
191 rcu_read_unlock();
192 nfs_inode_set_delegation(inode, cred, res);
193 }
194 } else {
195 rcu_read_unlock();
196 }
197}
198
199static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
200{
201 int res = 0;
202
203 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
204 res = nfs4_proc_delegreturn(inode,
205 delegation->cred,
206 &delegation->stateid,
207 issync);
208 nfs_free_delegation(delegation);
209 return res;
210}
211
212static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
213{
214 struct inode *inode = NULL;
215
216 spin_lock(&delegation->lock);
217 if (delegation->inode != NULL)
218 inode = igrab(delegation->inode);
219 spin_unlock(&delegation->lock);
220 return inode;
221}
222
223static struct nfs_delegation *
224nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
225{
226 struct nfs_delegation *ret = NULL;
227 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
228
229 if (delegation == NULL)
230 goto out;
231 spin_lock(&delegation->lock);
232 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
233 ret = delegation;
234 spin_unlock(&delegation->lock);
235out:
236 return ret;
237}
238
239static struct nfs_delegation *
240nfs_start_delegation_return(struct nfs_inode *nfsi)
241{
242 struct nfs_delegation *delegation;
243
244 rcu_read_lock();
245 delegation = nfs_start_delegation_return_locked(nfsi);
246 rcu_read_unlock();
247 return delegation;
248}
249
250static void
251nfs_abort_delegation_return(struct nfs_delegation *delegation,
252 struct nfs_client *clp)
253{
254
255 spin_lock(&delegation->lock);
256 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
257 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
258 spin_unlock(&delegation->lock);
259 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
260}
261
262static struct nfs_delegation *
263nfs_detach_delegation_locked(struct nfs_inode *nfsi,
264 struct nfs_delegation *delegation,
265 struct nfs_client *clp)
266{
267 struct nfs_delegation *deleg_cur =
268 rcu_dereference_protected(nfsi->delegation,
269 lockdep_is_held(&clp->cl_lock));
270
271 if (deleg_cur == NULL || delegation != deleg_cur)
272 return NULL;
273
274 spin_lock(&delegation->lock);
275 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
276 list_del_rcu(&delegation->super_list);
277 delegation->inode = NULL;
278 rcu_assign_pointer(nfsi->delegation, NULL);
279 spin_unlock(&delegation->lock);
280 return delegation;
281}
282
283static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
284 struct nfs_delegation *delegation,
285 struct nfs_server *server)
286{
287 struct nfs_client *clp = server->nfs_client;
288
289 spin_lock(&clp->cl_lock);
290 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
291 spin_unlock(&clp->cl_lock);
292 return delegation;
293}
294
295static struct nfs_delegation *
296nfs_inode_detach_delegation(struct inode *inode)
297{
298 struct nfs_inode *nfsi = NFS_I(inode);
299 struct nfs_server *server = NFS_SERVER(inode);
300 struct nfs_delegation *delegation;
301
302 delegation = nfs_start_delegation_return(nfsi);
303 if (delegation == NULL)
304 return NULL;
305 return nfs_detach_delegation(nfsi, delegation, server);
306}
307
308static void
309nfs_update_inplace_delegation(struct nfs_delegation *delegation,
310 const struct nfs_delegation *update)
311{
312 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
313 delegation->stateid.seqid = update->stateid.seqid;
314 smp_wmb();
315 delegation->type = update->type;
316 }
317}
318
319/**
320 * nfs_inode_set_delegation - set up a delegation on an inode
321 * @inode: inode to which delegation applies
322 * @cred: cred to use for subsequent delegation processing
323 * @res: new delegation state from server
324 *
325 * Returns zero on success, or a negative errno value.
326 */
327int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
328{
329 struct nfs_server *server = NFS_SERVER(inode);
330 struct nfs_client *clp = server->nfs_client;
331 struct nfs_inode *nfsi = NFS_I(inode);
332 struct nfs_delegation *delegation, *old_delegation;
333 struct nfs_delegation *freeme = NULL;
334 int status = 0;
335
336 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
337 if (delegation == NULL)
338 return -ENOMEM;
339 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
340 delegation->type = res->delegation_type;
341 delegation->pagemod_limit = res->pagemod_limit;
342 delegation->change_attr = inode->i_version;
343 delegation->cred = get_rpccred(cred);
344 delegation->inode = inode;
345 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
346 spin_lock_init(&delegation->lock);
347
348 spin_lock(&clp->cl_lock);
349 old_delegation = rcu_dereference_protected(nfsi->delegation,
350 lockdep_is_held(&clp->cl_lock));
351 if (old_delegation != NULL) {
352 /* Is this an update of the existing delegation? */
353 if (nfs4_stateid_match_other(&old_delegation->stateid,
354 &delegation->stateid)) {
355 nfs_update_inplace_delegation(old_delegation,
356 delegation);
357 goto out;
358 }
359 /*
360 * Deal with broken servers that hand out two
361 * delegations for the same file.
362 * Allow for upgrades to a WRITE delegation, but
363 * nothing else.
364 */
365 dfprintk(FILE, "%s: server %s handed out "
366 "a duplicate delegation!\n",
367 __func__, clp->cl_hostname);
368 if (delegation->type == old_delegation->type ||
369 !(delegation->type & FMODE_WRITE)) {
370 freeme = delegation;
371 delegation = NULL;
372 goto out;
373 }
374 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
375 &old_delegation->flags))
376 goto out;
377 freeme = nfs_detach_delegation_locked(nfsi,
378 old_delegation, clp);
379 if (freeme == NULL)
380 goto out;
381 }
382 list_add_tail_rcu(&delegation->super_list, &server->delegations);
383 rcu_assign_pointer(nfsi->delegation, delegation);
384 delegation = NULL;
385
386 /* Ensure we revalidate the attributes and page cache! */
387 spin_lock(&inode->i_lock);
388 nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
389 spin_unlock(&inode->i_lock);
390 trace_nfs4_set_delegation(inode, res->delegation_type);
391
392out:
393 spin_unlock(&clp->cl_lock);
394 if (delegation != NULL)
395 nfs_free_delegation(delegation);
396 if (freeme != NULL)
397 nfs_do_return_delegation(inode, freeme, 0);
398 return status;
399}
400
401/*
402 * Basic procedure for returning a delegation to the server
403 */
404static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
405{
406 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
407 struct nfs_inode *nfsi = NFS_I(inode);
408 int err = 0;
409
410 if (delegation == NULL)
411 return 0;
412 do {
413 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
414 break;
415 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
416 delegation->type);
417 if (!issync || err != -EAGAIN)
418 break;
419 /*
420 * Guard against state recovery
421 */
422 err = nfs4_wait_clnt_recover(clp);
423 } while (err == 0);
424
425 if (err) {
426 nfs_abort_delegation_return(delegation, clp);
427 goto out;
428 }
429 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
430 goto out;
431
432 err = nfs_do_return_delegation(inode, delegation, issync);
433out:
434 return err;
435}
436
437static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
438{
439 bool ret = false;
440
441 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
442 goto out;
443 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
444 ret = true;
445 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
446 struct inode *inode;
447
448 spin_lock(&delegation->lock);
449 inode = delegation->inode;
450 if (inode && list_empty(&NFS_I(inode)->open_files))
451 ret = true;
452 spin_unlock(&delegation->lock);
453 }
454out:
455 return ret;
456}
457
458/**
459 * nfs_client_return_marked_delegations - return previously marked delegations
460 * @clp: nfs_client to process
461 *
462 * Note that this function is designed to be called by the state
463 * manager thread. For this reason, it cannot flush the dirty data,
464 * since that could deadlock in case of a state recovery error.
465 *
466 * Returns zero on success, or a negative errno value.
467 */
468int nfs_client_return_marked_delegations(struct nfs_client *clp)
469{
470 struct nfs_delegation *delegation;
471 struct nfs_server *server;
472 struct inode *inode;
473 int err = 0;
474
475restart:
476 rcu_read_lock();
477 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
478 list_for_each_entry_rcu(delegation, &server->delegations,
479 super_list) {
480 if (!nfs_delegation_need_return(delegation))
481 continue;
482 if (!nfs_sb_active(server->super))
483 continue;
484 inode = nfs_delegation_grab_inode(delegation);
485 if (inode == NULL) {
486 rcu_read_unlock();
487 nfs_sb_deactive(server->super);
488 goto restart;
489 }
490 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
491 rcu_read_unlock();
492
493 err = nfs_end_delegation_return(inode, delegation, 0);
494 iput(inode);
495 nfs_sb_deactive(server->super);
496 if (!err)
497 goto restart;
498 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
499 return err;
500 }
501 }
502 rcu_read_unlock();
503 return 0;
504}
505
506/**
507 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
508 * @inode: inode to process
509 *
510 * Does not protect against delegation reclaims, therefore really only safe
511 * to be called from nfs4_clear_inode().
512 */
513void nfs_inode_return_delegation_noreclaim(struct inode *inode)
514{
515 struct nfs_delegation *delegation;
516
517 delegation = nfs_inode_detach_delegation(inode);
518 if (delegation != NULL)
519 nfs_do_return_delegation(inode, delegation, 1);
520}
521
522/**
523 * nfs_inode_return_delegation - synchronously return a delegation
524 * @inode: inode to process
525 *
526 * This routine will always flush any dirty data to disk on the
527 * assumption that if we need to return the delegation, then
528 * we should stop caching.
529 *
530 * Returns zero on success, or a negative errno value.
531 */
532int nfs4_inode_return_delegation(struct inode *inode)
533{
534 struct nfs_inode *nfsi = NFS_I(inode);
535 struct nfs_delegation *delegation;
536 int err = 0;
537
538 nfs_wb_all(inode);
539 delegation = nfs_start_delegation_return(nfsi);
540 if (delegation != NULL)
541 err = nfs_end_delegation_return(inode, delegation, 1);
542 return err;
543}
544
545static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
546 struct nfs_delegation *delegation)
547{
548 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
549 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
550}
551
552static void nfs_mark_return_delegation(struct nfs_server *server,
553 struct nfs_delegation *delegation)
554{
555 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
556 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
557}
558
559static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
560{
561 struct nfs_delegation *delegation;
562 bool ret = false;
563
564 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
565 nfs_mark_return_delegation(server, delegation);
566 ret = true;
567 }
568 return ret;
569}
570
571static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
572{
573 struct nfs_server *server;
574
575 rcu_read_lock();
576 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
577 nfs_server_mark_return_all_delegations(server);
578 rcu_read_unlock();
579}
580
581static void nfs_delegation_run_state_manager(struct nfs_client *clp)
582{
583 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
584 nfs4_schedule_state_manager(clp);
585}
586
587/**
588 * nfs_expire_all_delegations
589 * @clp: client to process
590 *
591 */
592void nfs_expire_all_delegations(struct nfs_client *clp)
593{
594 nfs_client_mark_return_all_delegations(clp);
595 nfs_delegation_run_state_manager(clp);
596}
597
598/**
599 * nfs_super_return_all_delegations - return delegations for one superblock
600 * @sb: sb to process
601 *
602 */
603void nfs_server_return_all_delegations(struct nfs_server *server)
604{
605 struct nfs_client *clp = server->nfs_client;
606 bool need_wait;
607
608 if (clp == NULL)
609 return;
610
611 rcu_read_lock();
612 need_wait = nfs_server_mark_return_all_delegations(server);
613 rcu_read_unlock();
614
615 if (need_wait) {
616 nfs4_schedule_state_manager(clp);
617 nfs4_wait_clnt_recover(clp);
618 }
619}
620
621static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
622 fmode_t flags)
623{
624 struct nfs_delegation *delegation;
625
626 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
627 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
628 continue;
629 if (delegation->type & flags)
630 nfs_mark_return_if_closed_delegation(server, delegation);
631 }
632}
633
634static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
635 fmode_t flags)
636{
637 struct nfs_server *server;
638
639 rcu_read_lock();
640 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
641 nfs_mark_return_unused_delegation_types(server, flags);
642 rcu_read_unlock();
643}
644
645static void nfs_revoke_delegation(struct inode *inode)
646{
647 struct nfs_delegation *delegation;
648 rcu_read_lock();
649 delegation = rcu_dereference(NFS_I(inode)->delegation);
650 if (delegation != NULL) {
651 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
652 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
653 }
654 rcu_read_unlock();
655}
656
657void nfs_remove_bad_delegation(struct inode *inode)
658{
659 struct nfs_delegation *delegation;
660
661 nfs_revoke_delegation(inode);
662 delegation = nfs_inode_detach_delegation(inode);
663 if (delegation) {
664 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
665 nfs_free_delegation(delegation);
666 }
667}
668EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
669
670/**
671 * nfs_expire_unused_delegation_types
672 * @clp: client to process
673 * @flags: delegation types to expire
674 *
675 */
676void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
677{
678 nfs_client_mark_return_unused_delegation_types(clp, flags);
679 nfs_delegation_run_state_manager(clp);
680}
681
682static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
683{
684 struct nfs_delegation *delegation;
685
686 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
687 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
688 continue;
689 nfs_mark_return_if_closed_delegation(server, delegation);
690 }
691}
692
693/**
694 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
695 * @clp: nfs_client to process
696 *
697 */
698void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
699{
700 struct nfs_server *server;
701
702 rcu_read_lock();
703 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
704 nfs_mark_return_unreferenced_delegations(server);
705 rcu_read_unlock();
706
707 nfs_delegation_run_state_manager(clp);
708}
709
710/**
711 * nfs_async_inode_return_delegation - asynchronously return a delegation
712 * @inode: inode to process
713 * @stateid: state ID information
714 *
715 * Returns zero on success, or a negative errno value.
716 */
717int nfs_async_inode_return_delegation(struct inode *inode,
718 const nfs4_stateid *stateid)
719{
720 struct nfs_server *server = NFS_SERVER(inode);
721 struct nfs_client *clp = server->nfs_client;
722 struct nfs_delegation *delegation;
723
724 rcu_read_lock();
725 delegation = rcu_dereference(NFS_I(inode)->delegation);
726 if (delegation == NULL)
727 goto out_enoent;
728 if (stateid != NULL &&
729 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
730 goto out_enoent;
731 nfs_mark_return_delegation(server, delegation);
732 rcu_read_unlock();
733
734 nfs_delegation_run_state_manager(clp);
735 return 0;
736out_enoent:
737 rcu_read_unlock();
738 return -ENOENT;
739}
740
741static struct inode *
742nfs_delegation_find_inode_server(struct nfs_server *server,
743 const struct nfs_fh *fhandle)
744{
745 struct nfs_delegation *delegation;
746 struct inode *res = NULL;
747
748 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
749 spin_lock(&delegation->lock);
750 if (delegation->inode != NULL &&
751 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
752 res = igrab(delegation->inode);
753 }
754 spin_unlock(&delegation->lock);
755 if (res != NULL)
756 break;
757 }
758 return res;
759}
760
761/**
762 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
763 * @clp: client state handle
764 * @fhandle: filehandle from a delegation recall
765 *
766 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
767 * cannot be found.
768 */
769struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
770 const struct nfs_fh *fhandle)
771{
772 struct nfs_server *server;
773 struct inode *res = NULL;
774
775 rcu_read_lock();
776 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
777 res = nfs_delegation_find_inode_server(server, fhandle);
778 if (res != NULL)
779 break;
780 }
781 rcu_read_unlock();
782 return res;
783}
784
785static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
786{
787 struct nfs_delegation *delegation;
788
789 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
790 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
791}
792
793/**
794 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
795 * @clp: nfs_client to process
796 *
797 */
798void nfs_delegation_mark_reclaim(struct nfs_client *clp)
799{
800 struct nfs_server *server;
801
802 rcu_read_lock();
803 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
804 nfs_delegation_mark_reclaim_server(server);
805 rcu_read_unlock();
806}
807
808/**
809 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
810 * @clp: nfs_client to process
811 *
812 */
813void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
814{
815 struct nfs_delegation *delegation;
816 struct nfs_server *server;
817 struct inode *inode;
818
819restart:
820 rcu_read_lock();
821 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
822 list_for_each_entry_rcu(delegation, &server->delegations,
823 super_list) {
824 if (test_bit(NFS_DELEGATION_RETURNING,
825 &delegation->flags))
826 continue;
827 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
828 &delegation->flags) == 0)
829 continue;
830 if (!nfs_sb_active(server->super))
831 continue;
832 inode = nfs_delegation_grab_inode(delegation);
833 if (inode == NULL) {
834 rcu_read_unlock();
835 nfs_sb_deactive(server->super);
836 goto restart;
837 }
838 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
839 rcu_read_unlock();
840 if (delegation != NULL) {
841 delegation = nfs_detach_delegation(NFS_I(inode),
842 delegation, server);
843 if (delegation != NULL)
844 nfs_free_delegation(delegation);
845 }
846 iput(inode);
847 nfs_sb_deactive(server->super);
848 goto restart;
849 }
850 }
851 rcu_read_unlock();
852}
853
854/**
855 * nfs_delegations_present - check for existence of delegations
856 * @clp: client state handle
857 *
858 * Returns one if there are any nfs_delegation structures attached
859 * to this nfs_client.
860 */
861int nfs_delegations_present(struct nfs_client *clp)
862{
863 struct nfs_server *server;
864 int ret = 0;
865
866 rcu_read_lock();
867 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
868 if (!list_empty(&server->delegations)) {
869 ret = 1;
870 break;
871 }
872 rcu_read_unlock();
873 return ret;
874}
875
876/**
877 * nfs4_copy_delegation_stateid - Copy inode's state ID information
878 * @dst: stateid data structure to fill in
879 * @inode: inode to check
880 * @flags: delegation type requirement
881 *
882 * Returns "true" and fills in "dst->data" * if inode had a delegation,
883 * otherwise "false" is returned.
884 */
885bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
886 fmode_t flags)
887{
888 struct nfs_inode *nfsi = NFS_I(inode);
889 struct nfs_delegation *delegation;
890 bool ret;
891
892 flags &= FMODE_READ|FMODE_WRITE;
893 rcu_read_lock();
894 delegation = rcu_dereference(nfsi->delegation);
895 ret = (delegation != NULL && (delegation->type & flags) == flags);
896 if (ret) {
897 nfs4_stateid_copy(dst, &delegation->stateid);
898 nfs_mark_delegation_referenced(delegation);
899 }
900 rcu_read_unlock();
901 return ret;
902}
903
904/**
905 * nfs4_delegation_flush_on_close - Check if we must flush file on close
906 * @inode: inode to check
907 *
908 * This function checks the number of outstanding writes to the file
909 * against the delegation 'space_limit' field to see if
910 * the spec requires us to flush the file on close.
911 */
912bool nfs4_delegation_flush_on_close(const struct inode *inode)
913{
914 struct nfs_inode *nfsi = NFS_I(inode);
915 struct nfs_delegation *delegation;
916 bool ret = true;
917
918 rcu_read_lock();
919 delegation = rcu_dereference(nfsi->delegation);
920 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
921 goto out;
922 if (nfsi->nrequests < delegation->pagemod_limit)
923 ret = false;
924out:
925 rcu_read_unlock();
926 return ret;
927}