2 * linux/fs/nfs/delegation.c
4 * Copyright (C) 2004 Trond Myklebust
6 * NFS file delegation management
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>
16 #include <linux/nfs4.h>
17 #include <linux/nfs_fs.h>
18 #include <linux/nfs_xdr.h>
21 #include "delegation.h"
23 #include "nfs4trace.h"
25 static void nfs_free_delegation(struct nfs_delegation
*delegation
)
27 if (delegation
->cred
) {
28 put_rpccred(delegation
->cred
);
29 delegation
->cred
= NULL
;
31 kfree_rcu(delegation
, rcu
);
35 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
36 * @delegation: delegation to process
39 void nfs_mark_delegation_referenced(struct nfs_delegation
*delegation
)
41 set_bit(NFS_DELEGATION_REFERENCED
, &delegation
->flags
);
45 nfs4_do_check_delegation(struct inode
*inode
, fmode_t flags
, bool mark
)
47 struct nfs_delegation
*delegation
;
50 flags
&= FMODE_READ
|FMODE_WRITE
;
52 delegation
= rcu_dereference(NFS_I(inode
)->delegation
);
53 if (delegation
!= NULL
&& (delegation
->type
& flags
) == flags
&&
54 !test_bit(NFS_DELEGATION_RETURNING
, &delegation
->flags
)) {
56 nfs_mark_delegation_referenced(delegation
);
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
68 * Returns one if inode has the indicated delegation, otherwise zero.
70 int nfs4_have_delegation(struct inode
*inode
, fmode_t flags
)
72 return nfs4_do_check_delegation(inode
, flags
, true);
76 * nfs4_check_delegation - check if inode has a delegation, do not mark
77 * NFS_DELEGATION_REFERENCED if it has one.
79 int nfs4_check_delegation(struct inode
*inode
, fmode_t flags
)
81 return nfs4_do_check_delegation(inode
, flags
, false);
84 static int nfs_delegation_claim_locks(struct nfs_open_context
*ctx
, struct nfs4_state
*state
, const nfs4_stateid
*stateid
)
86 struct inode
*inode
= state
->inode
;
88 struct file_lock_context
*flctx
= inode
->i_flctx
;
89 struct list_head
*list
;
95 list
= &flctx
->flc_posix
;
96 spin_lock(&flctx
->flc_lock
);
98 list_for_each_entry(fl
, list
, fl_list
) {
99 if (nfs_file_open_context(fl
->fl_file
) != ctx
)
101 spin_unlock(&flctx
->flc_lock
);
102 status
= nfs4_lock_delegation_recall(fl
, state
, stateid
);
105 spin_lock(&flctx
->flc_lock
);
107 if (list
== &flctx
->flc_posix
) {
108 list
= &flctx
->flc_flock
;
111 spin_unlock(&flctx
->flc_lock
);
116 static int nfs_delegation_claim_opens(struct inode
*inode
, const nfs4_stateid
*stateid
)
118 struct nfs_inode
*nfsi
= NFS_I(inode
);
119 struct nfs_open_context
*ctx
;
120 struct nfs4_state_owner
*sp
;
121 struct nfs4_state
*state
;
126 spin_lock(&inode
->i_lock
);
127 list_for_each_entry(ctx
, &nfsi
->open_files
, list
) {
131 if (!test_bit(NFS_DELEGATED_STATE
, &state
->flags
))
133 if (!nfs4_valid_open_stateid(state
))
135 if (!nfs4_stateid_match(&state
->stateid
, stateid
))
137 get_nfs_open_context(ctx
);
138 spin_unlock(&inode
->i_lock
);
140 /* Block nfs4_proc_unlck */
141 mutex_lock(&sp
->so_delegreturn_mutex
);
142 seq
= raw_seqcount_begin(&sp
->so_reclaim_seqcount
);
143 err
= nfs4_open_delegation_recall(ctx
, state
, stateid
);
145 err
= nfs_delegation_claim_locks(ctx
, state
, stateid
);
146 if (!err
&& read_seqcount_retry(&sp
->so_reclaim_seqcount
, seq
))
148 mutex_unlock(&sp
->so_delegreturn_mutex
);
149 put_nfs_open_context(ctx
);
154 spin_unlock(&inode
->i_lock
);
159 * nfs_inode_reclaim_delegation - process a delegation reclaim request
160 * @inode: inode to process
161 * @cred: credential to use for request
162 * @res: new delegation state from server
165 void nfs_inode_reclaim_delegation(struct inode
*inode
, struct rpc_cred
*cred
,
166 struct nfs_openres
*res
)
168 struct nfs_delegation
*delegation
;
169 struct rpc_cred
*oldcred
= NULL
;
172 delegation
= rcu_dereference(NFS_I(inode
)->delegation
);
173 if (delegation
!= NULL
) {
174 spin_lock(&delegation
->lock
);
175 if (delegation
->inode
!= NULL
) {
176 nfs4_stateid_copy(&delegation
->stateid
, &res
->delegation
);
177 delegation
->type
= res
->delegation_type
;
178 delegation
->maxsize
= res
->maxsize
;
179 oldcred
= delegation
->cred
;
180 delegation
->cred
= get_rpccred(cred
);
181 clear_bit(NFS_DELEGATION_NEED_RECLAIM
,
183 spin_unlock(&delegation
->lock
);
184 put_rpccred(oldcred
);
186 trace_nfs4_reclaim_delegation(inode
, res
->delegation_type
);
188 /* We appear to have raced with a delegation return. */
189 spin_unlock(&delegation
->lock
);
191 nfs_inode_set_delegation(inode
, cred
, res
);
198 static int nfs_do_return_delegation(struct inode
*inode
, struct nfs_delegation
*delegation
, int issync
)
202 if (!test_bit(NFS_DELEGATION_REVOKED
, &delegation
->flags
))
203 res
= nfs4_proc_delegreturn(inode
,
205 &delegation
->stateid
,
207 nfs_free_delegation(delegation
);
211 static struct inode
*nfs_delegation_grab_inode(struct nfs_delegation
*delegation
)
213 struct inode
*inode
= NULL
;
215 spin_lock(&delegation
->lock
);
216 if (delegation
->inode
!= NULL
)
217 inode
= igrab(delegation
->inode
);
218 spin_unlock(&delegation
->lock
);
222 static struct nfs_delegation
*
223 nfs_start_delegation_return_locked(struct nfs_inode
*nfsi
)
225 struct nfs_delegation
*ret
= NULL
;
226 struct nfs_delegation
*delegation
= rcu_dereference(nfsi
->delegation
);
228 if (delegation
== NULL
)
230 spin_lock(&delegation
->lock
);
231 if (!test_and_set_bit(NFS_DELEGATION_RETURNING
, &delegation
->flags
))
233 spin_unlock(&delegation
->lock
);
238 static struct nfs_delegation
*
239 nfs_start_delegation_return(struct nfs_inode
*nfsi
)
241 struct nfs_delegation
*delegation
;
244 delegation
= nfs_start_delegation_return_locked(nfsi
);
250 nfs_abort_delegation_return(struct nfs_delegation
*delegation
,
251 struct nfs_client
*clp
)
254 spin_lock(&delegation
->lock
);
255 clear_bit(NFS_DELEGATION_RETURNING
, &delegation
->flags
);
256 set_bit(NFS_DELEGATION_RETURN
, &delegation
->flags
);
257 spin_unlock(&delegation
->lock
);
258 set_bit(NFS4CLNT_DELEGRETURN
, &clp
->cl_state
);
261 static struct nfs_delegation
*
262 nfs_detach_delegation_locked(struct nfs_inode
*nfsi
,
263 struct nfs_delegation
*delegation
,
264 struct nfs_client
*clp
)
266 struct nfs_delegation
*deleg_cur
=
267 rcu_dereference_protected(nfsi
->delegation
,
268 lockdep_is_held(&clp
->cl_lock
));
270 if (deleg_cur
== NULL
|| delegation
!= deleg_cur
)
273 spin_lock(&delegation
->lock
);
274 set_bit(NFS_DELEGATION_RETURNING
, &delegation
->flags
);
275 list_del_rcu(&delegation
->super_list
);
276 delegation
->inode
= NULL
;
277 rcu_assign_pointer(nfsi
->delegation
, NULL
);
278 spin_unlock(&delegation
->lock
);
282 static struct nfs_delegation
*nfs_detach_delegation(struct nfs_inode
*nfsi
,
283 struct nfs_delegation
*delegation
,
284 struct nfs_server
*server
)
286 struct nfs_client
*clp
= server
->nfs_client
;
288 spin_lock(&clp
->cl_lock
);
289 delegation
= nfs_detach_delegation_locked(nfsi
, delegation
, clp
);
290 spin_unlock(&clp
->cl_lock
);
294 static struct nfs_delegation
*
295 nfs_inode_detach_delegation(struct inode
*inode
)
297 struct nfs_inode
*nfsi
= NFS_I(inode
);
298 struct nfs_server
*server
= NFS_SERVER(inode
);
299 struct nfs_delegation
*delegation
;
301 delegation
= nfs_start_delegation_return(nfsi
);
302 if (delegation
== NULL
)
304 return nfs_detach_delegation(nfsi
, delegation
, server
);
308 nfs_update_inplace_delegation(struct nfs_delegation
*delegation
,
309 const struct nfs_delegation
*update
)
311 if (nfs4_stateid_is_newer(&update
->stateid
, &delegation
->stateid
)) {
312 delegation
->stateid
.seqid
= update
->stateid
.seqid
;
314 delegation
->type
= update
->type
;
319 * nfs_inode_set_delegation - set up a delegation on an inode
320 * @inode: inode to which delegation applies
321 * @cred: cred to use for subsequent delegation processing
322 * @res: new delegation state from server
324 * Returns zero on success, or a negative errno value.
326 int nfs_inode_set_delegation(struct inode
*inode
, struct rpc_cred
*cred
, struct nfs_openres
*res
)
328 struct nfs_server
*server
= NFS_SERVER(inode
);
329 struct nfs_client
*clp
= server
->nfs_client
;
330 struct nfs_inode
*nfsi
= NFS_I(inode
);
331 struct nfs_delegation
*delegation
, *old_delegation
;
332 struct nfs_delegation
*freeme
= NULL
;
335 delegation
= kmalloc(sizeof(*delegation
), GFP_NOFS
);
336 if (delegation
== NULL
)
338 nfs4_stateid_copy(&delegation
->stateid
, &res
->delegation
);
339 delegation
->type
= res
->delegation_type
;
340 delegation
->maxsize
= res
->maxsize
;
341 delegation
->change_attr
= inode
->i_version
;
342 delegation
->cred
= get_rpccred(cred
);
343 delegation
->inode
= inode
;
344 delegation
->flags
= 1<<NFS_DELEGATION_REFERENCED
;
345 spin_lock_init(&delegation
->lock
);
347 spin_lock(&clp
->cl_lock
);
348 old_delegation
= rcu_dereference_protected(nfsi
->delegation
,
349 lockdep_is_held(&clp
->cl_lock
));
350 if (old_delegation
!= NULL
) {
351 /* Is this an update of the existing delegation? */
352 if (nfs4_stateid_match_other(&old_delegation
->stateid
,
353 &delegation
->stateid
)) {
354 nfs_update_inplace_delegation(old_delegation
,
359 * Deal with broken servers that hand out two
360 * delegations for the same file.
361 * Allow for upgrades to a WRITE delegation, but
364 dfprintk(FILE, "%s: server %s handed out "
365 "a duplicate delegation!\n",
366 __func__
, clp
->cl_hostname
);
367 if (delegation
->type
== old_delegation
->type
||
368 !(delegation
->type
& FMODE_WRITE
)) {
373 freeme
= nfs_detach_delegation_locked(nfsi
,
374 old_delegation
, clp
);
378 list_add_rcu(&delegation
->super_list
, &server
->delegations
);
379 rcu_assign_pointer(nfsi
->delegation
, delegation
);
382 /* Ensure we revalidate the attributes and page cache! */
383 spin_lock(&inode
->i_lock
);
384 nfsi
->cache_validity
|= NFS_INO_REVAL_FORCED
;
385 spin_unlock(&inode
->i_lock
);
386 trace_nfs4_set_delegation(inode
, res
->delegation_type
);
389 spin_unlock(&clp
->cl_lock
);
390 if (delegation
!= NULL
)
391 nfs_free_delegation(delegation
);
393 nfs_do_return_delegation(inode
, freeme
, 0);
398 * Basic procedure for returning a delegation to the server
400 static int nfs_end_delegation_return(struct inode
*inode
, struct nfs_delegation
*delegation
, int issync
)
402 struct nfs_client
*clp
= NFS_SERVER(inode
)->nfs_client
;
403 struct nfs_inode
*nfsi
= NFS_I(inode
);
406 if (delegation
== NULL
)
409 if (test_bit(NFS_DELEGATION_REVOKED
, &delegation
->flags
))
411 err
= nfs_delegation_claim_opens(inode
, &delegation
->stateid
);
412 if (!issync
|| err
!= -EAGAIN
)
415 * Guard against state recovery
417 err
= nfs4_wait_clnt_recover(clp
);
421 nfs_abort_delegation_return(delegation
, clp
);
424 if (!nfs_detach_delegation(nfsi
, delegation
, NFS_SERVER(inode
)))
427 err
= nfs_do_return_delegation(inode
, delegation
, issync
);
432 static bool nfs_delegation_need_return(struct nfs_delegation
*delegation
)
436 if (test_and_clear_bit(NFS_DELEGATION_RETURN
, &delegation
->flags
))
438 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED
, &delegation
->flags
) && !ret
) {
441 spin_lock(&delegation
->lock
);
442 inode
= delegation
->inode
;
443 if (inode
&& list_empty(&NFS_I(inode
)->open_files
))
445 spin_unlock(&delegation
->lock
);
451 * nfs_client_return_marked_delegations - return previously marked delegations
452 * @clp: nfs_client to process
454 * Note that this function is designed to be called by the state
455 * manager thread. For this reason, it cannot flush the dirty data,
456 * since that could deadlock in case of a state recovery error.
458 * Returns zero on success, or a negative errno value.
460 int nfs_client_return_marked_delegations(struct nfs_client
*clp
)
462 struct nfs_delegation
*delegation
;
463 struct nfs_server
*server
;
469 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
) {
470 list_for_each_entry_rcu(delegation
, &server
->delegations
,
472 if (!nfs_delegation_need_return(delegation
))
474 inode
= nfs_delegation_grab_inode(delegation
);
477 delegation
= nfs_start_delegation_return_locked(NFS_I(inode
));
480 err
= nfs_end_delegation_return(inode
, delegation
, 0);
484 set_bit(NFS4CLNT_DELEGRETURN
, &clp
->cl_state
);
493 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
494 * @inode: inode to process
496 * Does not protect against delegation reclaims, therefore really only safe
497 * to be called from nfs4_clear_inode().
499 void nfs_inode_return_delegation_noreclaim(struct inode
*inode
)
501 struct nfs_delegation
*delegation
;
503 delegation
= nfs_inode_detach_delegation(inode
);
504 if (delegation
!= NULL
)
505 nfs_do_return_delegation(inode
, delegation
, 0);
509 * nfs_inode_return_delegation - synchronously return a delegation
510 * @inode: inode to process
512 * This routine will always flush any dirty data to disk on the
513 * assumption that if we need to return the delegation, then
514 * we should stop caching.
516 * Returns zero on success, or a negative errno value.
518 int nfs4_inode_return_delegation(struct inode
*inode
)
520 struct nfs_inode
*nfsi
= NFS_I(inode
);
521 struct nfs_delegation
*delegation
;
525 delegation
= nfs_start_delegation_return(nfsi
);
526 if (delegation
!= NULL
)
527 err
= nfs_end_delegation_return(inode
, delegation
, 1);
531 static void nfs_mark_return_if_closed_delegation(struct nfs_server
*server
,
532 struct nfs_delegation
*delegation
)
534 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED
, &delegation
->flags
);
535 set_bit(NFS4CLNT_DELEGRETURN
, &server
->nfs_client
->cl_state
);
538 static void nfs_mark_return_delegation(struct nfs_server
*server
,
539 struct nfs_delegation
*delegation
)
541 set_bit(NFS_DELEGATION_RETURN
, &delegation
->flags
);
542 set_bit(NFS4CLNT_DELEGRETURN
, &server
->nfs_client
->cl_state
);
545 static bool nfs_server_mark_return_all_delegations(struct nfs_server
*server
)
547 struct nfs_delegation
*delegation
;
550 list_for_each_entry_rcu(delegation
, &server
->delegations
, super_list
) {
551 nfs_mark_return_delegation(server
, delegation
);
557 static void nfs_client_mark_return_all_delegations(struct nfs_client
*clp
)
559 struct nfs_server
*server
;
562 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
)
563 nfs_server_mark_return_all_delegations(server
);
567 static void nfs_delegation_run_state_manager(struct nfs_client
*clp
)
569 if (test_bit(NFS4CLNT_DELEGRETURN
, &clp
->cl_state
))
570 nfs4_schedule_state_manager(clp
);
574 * nfs_expire_all_delegations
575 * @clp: client to process
578 void nfs_expire_all_delegations(struct nfs_client
*clp
)
580 nfs_client_mark_return_all_delegations(clp
);
581 nfs_delegation_run_state_manager(clp
);
585 * nfs_super_return_all_delegations - return delegations for one superblock
589 void nfs_server_return_all_delegations(struct nfs_server
*server
)
591 struct nfs_client
*clp
= server
->nfs_client
;
598 need_wait
= nfs_server_mark_return_all_delegations(server
);
602 nfs4_schedule_state_manager(clp
);
603 nfs4_wait_clnt_recover(clp
);
607 static void nfs_mark_return_unused_delegation_types(struct nfs_server
*server
,
610 struct nfs_delegation
*delegation
;
612 list_for_each_entry_rcu(delegation
, &server
->delegations
, super_list
) {
613 if ((delegation
->type
== (FMODE_READ
|FMODE_WRITE
)) && !(flags
& FMODE_WRITE
))
615 if (delegation
->type
& flags
)
616 nfs_mark_return_if_closed_delegation(server
, delegation
);
620 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client
*clp
,
623 struct nfs_server
*server
;
626 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
)
627 nfs_mark_return_unused_delegation_types(server
, flags
);
631 static void nfs_revoke_delegation(struct inode
*inode
)
633 struct nfs_delegation
*delegation
;
635 delegation
= rcu_dereference(NFS_I(inode
)->delegation
);
636 if (delegation
!= NULL
) {
637 set_bit(NFS_DELEGATION_REVOKED
, &delegation
->flags
);
638 nfs_mark_return_delegation(NFS_SERVER(inode
), delegation
);
643 void nfs_remove_bad_delegation(struct inode
*inode
)
645 struct nfs_delegation
*delegation
;
647 nfs_revoke_delegation(inode
);
648 delegation
= nfs_inode_detach_delegation(inode
);
650 nfs_inode_find_state_and_recover(inode
, &delegation
->stateid
);
651 nfs_free_delegation(delegation
);
654 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation
);
657 * nfs_expire_unused_delegation_types
658 * @clp: client to process
659 * @flags: delegation types to expire
662 void nfs_expire_unused_delegation_types(struct nfs_client
*clp
, fmode_t flags
)
664 nfs_client_mark_return_unused_delegation_types(clp
, flags
);
665 nfs_delegation_run_state_manager(clp
);
668 static void nfs_mark_return_unreferenced_delegations(struct nfs_server
*server
)
670 struct nfs_delegation
*delegation
;
672 list_for_each_entry_rcu(delegation
, &server
->delegations
, super_list
) {
673 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED
, &delegation
->flags
))
675 nfs_mark_return_if_closed_delegation(server
, delegation
);
680 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
681 * @clp: nfs_client to process
684 void nfs_expire_unreferenced_delegations(struct nfs_client
*clp
)
686 struct nfs_server
*server
;
689 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
)
690 nfs_mark_return_unreferenced_delegations(server
);
693 nfs_delegation_run_state_manager(clp
);
697 * nfs_async_inode_return_delegation - asynchronously return a delegation
698 * @inode: inode to process
699 * @stateid: state ID information
701 * Returns zero on success, or a negative errno value.
703 int nfs_async_inode_return_delegation(struct inode
*inode
,
704 const nfs4_stateid
*stateid
)
706 struct nfs_server
*server
= NFS_SERVER(inode
);
707 struct nfs_client
*clp
= server
->nfs_client
;
708 struct nfs_delegation
*delegation
;
710 filemap_flush(inode
->i_mapping
);
713 delegation
= rcu_dereference(NFS_I(inode
)->delegation
);
714 if (delegation
== NULL
)
717 if (!clp
->cl_mvops
->match_stateid(&delegation
->stateid
, stateid
))
719 nfs_mark_return_delegation(server
, delegation
);
722 nfs_delegation_run_state_manager(clp
);
729 static struct inode
*
730 nfs_delegation_find_inode_server(struct nfs_server
*server
,
731 const struct nfs_fh
*fhandle
)
733 struct nfs_delegation
*delegation
;
734 struct inode
*res
= NULL
;
736 list_for_each_entry_rcu(delegation
, &server
->delegations
, super_list
) {
737 spin_lock(&delegation
->lock
);
738 if (delegation
->inode
!= NULL
&&
739 nfs_compare_fh(fhandle
, &NFS_I(delegation
->inode
)->fh
) == 0) {
740 res
= igrab(delegation
->inode
);
742 spin_unlock(&delegation
->lock
);
750 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
751 * @clp: client state handle
752 * @fhandle: filehandle from a delegation recall
754 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
757 struct inode
*nfs_delegation_find_inode(struct nfs_client
*clp
,
758 const struct nfs_fh
*fhandle
)
760 struct nfs_server
*server
;
761 struct inode
*res
= NULL
;
764 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
) {
765 res
= nfs_delegation_find_inode_server(server
, fhandle
);
773 static void nfs_delegation_mark_reclaim_server(struct nfs_server
*server
)
775 struct nfs_delegation
*delegation
;
777 list_for_each_entry_rcu(delegation
, &server
->delegations
, super_list
)
778 set_bit(NFS_DELEGATION_NEED_RECLAIM
, &delegation
->flags
);
782 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
783 * @clp: nfs_client to process
786 void nfs_delegation_mark_reclaim(struct nfs_client
*clp
)
788 struct nfs_server
*server
;
791 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
)
792 nfs_delegation_mark_reclaim_server(server
);
797 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
798 * @clp: nfs_client to process
801 void nfs_delegation_reap_unclaimed(struct nfs_client
*clp
)
803 struct nfs_delegation
*delegation
;
804 struct nfs_server
*server
;
809 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
) {
810 list_for_each_entry_rcu(delegation
, &server
->delegations
,
812 if (test_bit(NFS_DELEGATION_NEED_RECLAIM
,
813 &delegation
->flags
) == 0)
815 inode
= nfs_delegation_grab_inode(delegation
);
818 delegation
= nfs_detach_delegation(NFS_I(inode
),
822 if (delegation
!= NULL
)
823 nfs_free_delegation(delegation
);
832 * nfs_delegations_present - check for existence of delegations
833 * @clp: client state handle
835 * Returns one if there are any nfs_delegation structures attached
836 * to this nfs_client.
838 int nfs_delegations_present(struct nfs_client
*clp
)
840 struct nfs_server
*server
;
844 list_for_each_entry_rcu(server
, &clp
->cl_superblocks
, client_link
)
845 if (!list_empty(&server
->delegations
)) {
854 * nfs4_copy_delegation_stateid - Copy inode's state ID information
855 * @dst: stateid data structure to fill in
856 * @inode: inode to check
857 * @flags: delegation type requirement
859 * Returns "true" and fills in "dst->data" * if inode had a delegation,
860 * otherwise "false" is returned.
862 bool nfs4_copy_delegation_stateid(nfs4_stateid
*dst
, struct inode
*inode
,
865 struct nfs_inode
*nfsi
= NFS_I(inode
);
866 struct nfs_delegation
*delegation
;
869 flags
&= FMODE_READ
|FMODE_WRITE
;
871 delegation
= rcu_dereference(nfsi
->delegation
);
872 ret
= (delegation
!= NULL
&& (delegation
->type
& flags
) == flags
);
874 nfs4_stateid_copy(dst
, &delegation
->stateid
);
875 nfs_mark_delegation_referenced(delegation
);