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