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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/fs/nfs/delegation.c
4  *
5  * Copyright (C) 2004 Trond Myklebust
6  *
7  * NFS file delegation management
8  *
9  */
10 #include <linux/completion.h>
11 #include <linux/kthread.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/iversion.h>
17 
18 #include <linux/nfs4.h>
19 #include <linux/nfs_fs.h>
20 #include <linux/nfs_xdr.h>
21 
22 #include "nfs4_fs.h"
23 #include "nfs4session.h"
24 #include "delegation.h"
25 #include "internal.h"
26 #include "nfs4trace.h"
27 
28 #define NFS_DEFAULT_DELEGATION_WATERMARK (5000U)
29 
30 static atomic_long_t nfs_active_delegations;
31 static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
32 
__nfs_free_delegation(struct nfs_delegation * delegation)33 static void __nfs_free_delegation(struct nfs_delegation *delegation)
34 {
35 	put_cred(delegation->cred);
36 	delegation->cred = NULL;
37 	kfree_rcu(delegation, rcu);
38 }
39 
nfs_mark_delegation_revoked(struct nfs_delegation * delegation)40 static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation)
41 {
42 	if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
43 		delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
44 		atomic_long_dec(&nfs_active_delegations);
45 		if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
46 			nfs_clear_verifier_delegated(delegation->inode);
47 	}
48 }
49 
nfs_get_delegation(struct nfs_delegation * delegation)50 static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
51 {
52 	refcount_inc(&delegation->refcount);
53 	return delegation;
54 }
55 
nfs_put_delegation(struct nfs_delegation * delegation)56 static void nfs_put_delegation(struct nfs_delegation *delegation)
57 {
58 	if (refcount_dec_and_test(&delegation->refcount))
59 		__nfs_free_delegation(delegation);
60 }
61 
nfs_free_delegation(struct nfs_delegation * delegation)62 static void nfs_free_delegation(struct nfs_delegation *delegation)
63 {
64 	nfs_mark_delegation_revoked(delegation);
65 	nfs_put_delegation(delegation);
66 }
67 
68 /**
69  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
70  * @delegation: delegation to process
71  *
72  */
nfs_mark_delegation_referenced(struct nfs_delegation * delegation)73 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
74 {
75 	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
76 }
77 
nfs_mark_return_delegation(struct nfs_server * server,struct nfs_delegation * delegation)78 static void nfs_mark_return_delegation(struct nfs_server *server,
79 				       struct nfs_delegation *delegation)
80 {
81 	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
82 	set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
83 }
84 
85 static bool
nfs4_is_valid_delegation(const struct nfs_delegation * delegation,fmode_t flags)86 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
87 		fmode_t flags)
88 {
89 	if (delegation != NULL && (delegation->type & flags) == flags &&
90 	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
91 	    !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
92 		return true;
93 	return false;
94 }
95 
nfs4_get_valid_delegation(const struct inode * inode)96 struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
97 {
98 	struct nfs_delegation *delegation;
99 
100 	delegation = rcu_dereference(NFS_I(inode)->delegation);
101 	if (nfs4_is_valid_delegation(delegation, 0))
102 		return delegation;
103 	return NULL;
104 }
105 
106 static int
nfs4_do_check_delegation(struct inode * inode,fmode_t flags,bool mark)107 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
108 {
109 	struct nfs_delegation *delegation;
110 	int ret = 0;
111 
112 	flags &= FMODE_READ|FMODE_WRITE;
113 	rcu_read_lock();
114 	delegation = rcu_dereference(NFS_I(inode)->delegation);
115 	if (nfs4_is_valid_delegation(delegation, flags)) {
116 		if (mark)
117 			nfs_mark_delegation_referenced(delegation);
118 		ret = 1;
119 	}
120 	rcu_read_unlock();
121 	return ret;
122 }
123 /**
124  * nfs4_have_delegation - check if inode has a delegation, mark it
125  * NFS_DELEGATION_REFERENCED if there is one.
126  * @inode: inode to check
127  * @flags: delegation types to check for
128  *
129  * Returns one if inode has the indicated delegation, otherwise zero.
130  */
nfs4_have_delegation(struct inode * inode,fmode_t flags)131 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
132 {
133 	return nfs4_do_check_delegation(inode, flags, true);
134 }
135 
136 /*
137  * nfs4_check_delegation - check if inode has a delegation, do not mark
138  * NFS_DELEGATION_REFERENCED if it has one.
139  */
nfs4_check_delegation(struct inode * inode,fmode_t flags)140 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
141 {
142 	return nfs4_do_check_delegation(inode, flags, false);
143 }
144 
nfs_delegation_claim_locks(struct nfs4_state * state,const nfs4_stateid * stateid)145 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
146 {
147 	struct inode *inode = state->inode;
148 	struct file_lock *fl;
149 	struct file_lock_context *flctx = locks_inode_context(inode);
150 	struct list_head *list;
151 	int status = 0;
152 
153 	if (flctx == NULL)
154 		goto out;
155 
156 	list = &flctx->flc_posix;
157 	spin_lock(&flctx->flc_lock);
158 restart:
159 	list_for_each_entry(fl, list, fl_list) {
160 		if (nfs_file_open_context(fl->fl_file)->state != state)
161 			continue;
162 		spin_unlock(&flctx->flc_lock);
163 		status = nfs4_lock_delegation_recall(fl, state, stateid);
164 		if (status < 0)
165 			goto out;
166 		spin_lock(&flctx->flc_lock);
167 	}
168 	if (list == &flctx->flc_posix) {
169 		list = &flctx->flc_flock;
170 		goto restart;
171 	}
172 	spin_unlock(&flctx->flc_lock);
173 out:
174 	return status;
175 }
176 
nfs_delegation_claim_opens(struct inode * inode,const nfs4_stateid * stateid,fmode_t type)177 static int nfs_delegation_claim_opens(struct inode *inode,
178 		const nfs4_stateid *stateid, fmode_t type)
179 {
180 	struct nfs_inode *nfsi = NFS_I(inode);
181 	struct nfs_open_context *ctx;
182 	struct nfs4_state_owner *sp;
183 	struct nfs4_state *state;
184 	unsigned int seq;
185 	int err;
186 
187 again:
188 	rcu_read_lock();
189 	list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
190 		state = ctx->state;
191 		if (state == NULL)
192 			continue;
193 		if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
194 			continue;
195 		if (!nfs4_valid_open_stateid(state))
196 			continue;
197 		if (!nfs4_stateid_match(&state->stateid, stateid))
198 			continue;
199 		if (!get_nfs_open_context(ctx))
200 			continue;
201 		rcu_read_unlock();
202 		sp = state->owner;
203 		/* Block nfs4_proc_unlck */
204 		mutex_lock(&sp->so_delegreturn_mutex);
205 		seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
206 		err = nfs4_open_delegation_recall(ctx, state, stateid);
207 		if (!err)
208 			err = nfs_delegation_claim_locks(state, stateid);
209 		if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
210 			err = -EAGAIN;
211 		mutex_unlock(&sp->so_delegreturn_mutex);
212 		put_nfs_open_context(ctx);
213 		if (err != 0)
214 			return err;
215 		goto again;
216 	}
217 	rcu_read_unlock();
218 	return 0;
219 }
220 
221 /**
222  * nfs_inode_reclaim_delegation - process a delegation reclaim request
223  * @inode: inode to process
224  * @cred: credential to use for request
225  * @type: delegation type
226  * @stateid: delegation stateid
227  * @pagemod_limit: write delegation "space_limit"
228  *
229  */
nfs_inode_reclaim_delegation(struct inode * inode,const struct cred * cred,fmode_t type,const nfs4_stateid * stateid,unsigned long pagemod_limit)230 void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
231 				  fmode_t type, const nfs4_stateid *stateid,
232 				  unsigned long pagemod_limit)
233 {
234 	struct nfs_delegation *delegation;
235 	const struct cred *oldcred = NULL;
236 
237 	rcu_read_lock();
238 	delegation = rcu_dereference(NFS_I(inode)->delegation);
239 	if (delegation != NULL) {
240 		spin_lock(&delegation->lock);
241 		nfs4_stateid_copy(&delegation->stateid, stateid);
242 		delegation->type = type;
243 		delegation->pagemod_limit = pagemod_limit;
244 		oldcred = delegation->cred;
245 		delegation->cred = get_cred(cred);
246 		clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
247 		if (test_and_clear_bit(NFS_DELEGATION_REVOKED,
248 				       &delegation->flags))
249 			atomic_long_inc(&nfs_active_delegations);
250 		spin_unlock(&delegation->lock);
251 		rcu_read_unlock();
252 		put_cred(oldcred);
253 		trace_nfs4_reclaim_delegation(inode, type);
254 	} else {
255 		rcu_read_unlock();
256 		nfs_inode_set_delegation(inode, cred, type, stateid,
257 					 pagemod_limit);
258 	}
259 }
260 
nfs_do_return_delegation(struct inode * inode,struct nfs_delegation * delegation,int issync)261 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
262 {
263 	const struct cred *cred;
264 	int res = 0;
265 
266 	if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
267 		spin_lock(&delegation->lock);
268 		cred = get_cred(delegation->cred);
269 		spin_unlock(&delegation->lock);
270 		res = nfs4_proc_delegreturn(inode, cred,
271 				&delegation->stateid,
272 				issync);
273 		put_cred(cred);
274 	}
275 	return res;
276 }
277 
nfs_delegation_grab_inode(struct nfs_delegation * delegation)278 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
279 {
280 	struct inode *inode = NULL;
281 
282 	spin_lock(&delegation->lock);
283 	if (delegation->inode != NULL)
284 		inode = igrab(delegation->inode);
285 	if (!inode)
286 		set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
287 	spin_unlock(&delegation->lock);
288 	return inode;
289 }
290 
291 static struct nfs_delegation *
nfs_start_delegation_return_locked(struct nfs_inode * nfsi)292 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
293 {
294 	struct nfs_delegation *ret = NULL;
295 	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
296 
297 	if (delegation == NULL)
298 		goto out;
299 	spin_lock(&delegation->lock);
300 	if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
301 		clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
302 		/* Refcount matched in nfs_end_delegation_return() */
303 		ret = nfs_get_delegation(delegation);
304 	}
305 	spin_unlock(&delegation->lock);
306 	if (ret)
307 		nfs_clear_verifier_delegated(&nfsi->vfs_inode);
308 out:
309 	return ret;
310 }
311 
312 static struct nfs_delegation *
nfs_start_delegation_return(struct nfs_inode * nfsi)313 nfs_start_delegation_return(struct nfs_inode *nfsi)
314 {
315 	struct nfs_delegation *delegation;
316 
317 	rcu_read_lock();
318 	delegation = nfs_start_delegation_return_locked(nfsi);
319 	rcu_read_unlock();
320 	return delegation;
321 }
322 
nfs_abort_delegation_return(struct nfs_delegation * delegation,struct nfs_client * clp,int err)323 static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
324 					struct nfs_client *clp, int err)
325 {
326 
327 	spin_lock(&delegation->lock);
328 	clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
329 	if (err == -EAGAIN) {
330 		set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
331 		set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state);
332 	}
333 	spin_unlock(&delegation->lock);
334 }
335 
336 static struct nfs_delegation *
nfs_detach_delegation_locked(struct nfs_inode * nfsi,struct nfs_delegation * delegation,struct nfs_client * clp)337 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
338 		struct nfs_delegation *delegation,
339 		struct nfs_client *clp)
340 {
341 	struct nfs_delegation *deleg_cur =
342 		rcu_dereference_protected(nfsi->delegation,
343 				lockdep_is_held(&clp->cl_lock));
344 
345 	if (deleg_cur == NULL || delegation != deleg_cur)
346 		return NULL;
347 
348 	spin_lock(&delegation->lock);
349 	if (!delegation->inode) {
350 		spin_unlock(&delegation->lock);
351 		return NULL;
352 	}
353 	list_del_rcu(&delegation->super_list);
354 	delegation->inode = NULL;
355 	rcu_assign_pointer(nfsi->delegation, NULL);
356 	spin_unlock(&delegation->lock);
357 	return delegation;
358 }
359 
nfs_detach_delegation(struct nfs_inode * nfsi,struct nfs_delegation * delegation,struct nfs_server * server)360 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
361 		struct nfs_delegation *delegation,
362 		struct nfs_server *server)
363 {
364 	struct nfs_client *clp = server->nfs_client;
365 
366 	spin_lock(&clp->cl_lock);
367 	delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
368 	spin_unlock(&clp->cl_lock);
369 	return delegation;
370 }
371 
372 static struct nfs_delegation *
nfs_inode_detach_delegation(struct inode * inode)373 nfs_inode_detach_delegation(struct inode *inode)
374 {
375 	struct nfs_inode *nfsi = NFS_I(inode);
376 	struct nfs_server *server = NFS_SERVER(inode);
377 	struct nfs_delegation *delegation;
378 
379 	rcu_read_lock();
380 	delegation = rcu_dereference(nfsi->delegation);
381 	if (delegation != NULL)
382 		delegation = nfs_detach_delegation(nfsi, delegation, server);
383 	rcu_read_unlock();
384 	return delegation;
385 }
386 
387 static void
nfs_update_delegation_cred(struct nfs_delegation * delegation,const struct cred * cred)388 nfs_update_delegation_cred(struct nfs_delegation *delegation,
389 		const struct cred *cred)
390 {
391 	const struct cred *old;
392 
393 	if (cred_fscmp(delegation->cred, cred) != 0) {
394 		old = xchg(&delegation->cred, get_cred(cred));
395 		put_cred(old);
396 	}
397 }
398 
399 static void
nfs_update_inplace_delegation(struct nfs_delegation * delegation,const struct nfs_delegation * update)400 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
401 		const struct nfs_delegation *update)
402 {
403 	if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
404 		delegation->stateid.seqid = update->stateid.seqid;
405 		smp_wmb();
406 		delegation->type = update->type;
407 		delegation->pagemod_limit = update->pagemod_limit;
408 		if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
409 			delegation->change_attr = update->change_attr;
410 			nfs_update_delegation_cred(delegation, update->cred);
411 			/* smp_mb__before_atomic() is implicit due to xchg() */
412 			clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
413 			atomic_long_inc(&nfs_active_delegations);
414 		}
415 	}
416 }
417 
418 /**
419  * nfs_inode_set_delegation - set up a delegation on an inode
420  * @inode: inode to which delegation applies
421  * @cred: cred to use for subsequent delegation processing
422  * @type: delegation type
423  * @stateid: delegation stateid
424  * @pagemod_limit: write delegation "space_limit"
425  *
426  * Returns zero on success, or a negative errno value.
427  */
nfs_inode_set_delegation(struct inode * inode,const struct cred * cred,fmode_t type,const nfs4_stateid * stateid,unsigned long pagemod_limit)428 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
429 				  fmode_t type,
430 				  const nfs4_stateid *stateid,
431 				  unsigned long pagemod_limit)
432 {
433 	struct nfs_server *server = NFS_SERVER(inode);
434 	struct nfs_client *clp = server->nfs_client;
435 	struct nfs_inode *nfsi = NFS_I(inode);
436 	struct nfs_delegation *delegation, *old_delegation;
437 	struct nfs_delegation *freeme = NULL;
438 	int status = 0;
439 
440 	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL_ACCOUNT);
441 	if (delegation == NULL)
442 		return -ENOMEM;
443 	nfs4_stateid_copy(&delegation->stateid, stateid);
444 	refcount_set(&delegation->refcount, 1);
445 	delegation->type = type;
446 	delegation->pagemod_limit = pagemod_limit;
447 	delegation->change_attr = inode_peek_iversion_raw(inode);
448 	delegation->cred = get_cred(cred);
449 	delegation->inode = inode;
450 	delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
451 	spin_lock_init(&delegation->lock);
452 
453 	spin_lock(&clp->cl_lock);
454 	old_delegation = rcu_dereference_protected(nfsi->delegation,
455 					lockdep_is_held(&clp->cl_lock));
456 	if (old_delegation == NULL)
457 		goto add_new;
458 	/* Is this an update of the existing delegation? */
459 	if (nfs4_stateid_match_other(&old_delegation->stateid,
460 				&delegation->stateid)) {
461 		spin_lock(&old_delegation->lock);
462 		nfs_update_inplace_delegation(old_delegation,
463 				delegation);
464 		spin_unlock(&old_delegation->lock);
465 		goto out;
466 	}
467 	if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
468 		/*
469 		 * Deal with broken servers that hand out two
470 		 * delegations for the same file.
471 		 * Allow for upgrades to a WRITE delegation, but
472 		 * nothing else.
473 		 */
474 		dfprintk(FILE, "%s: server %s handed out "
475 				"a duplicate delegation!\n",
476 				__func__, clp->cl_hostname);
477 		if (delegation->type == old_delegation->type ||
478 		    !(delegation->type & FMODE_WRITE)) {
479 			freeme = delegation;
480 			delegation = NULL;
481 			goto out;
482 		}
483 		if (test_and_set_bit(NFS_DELEGATION_RETURNING,
484 					&old_delegation->flags))
485 			goto out;
486 	}
487 	freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
488 	if (freeme == NULL)
489 		goto out;
490 add_new:
491 	/*
492 	 * If we didn't revalidate the change attribute before setting
493 	 * the delegation, then pre-emptively ask for a full attribute
494 	 * cache revalidation.
495 	 */
496 	spin_lock(&inode->i_lock);
497 	if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
498 		nfs_set_cache_invalid(inode,
499 			NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
500 			NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
501 			NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
502 			NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
503 			NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
504 			NFS_INO_INVALID_XATTR);
505 	spin_unlock(&inode->i_lock);
506 
507 	list_add_tail_rcu(&delegation->super_list, &server->delegations);
508 	rcu_assign_pointer(nfsi->delegation, delegation);
509 	delegation = NULL;
510 
511 	atomic_long_inc(&nfs_active_delegations);
512 
513 	trace_nfs4_set_delegation(inode, type);
514 out:
515 	spin_unlock(&clp->cl_lock);
516 	if (delegation != NULL)
517 		__nfs_free_delegation(delegation);
518 	if (freeme != NULL) {
519 		nfs_do_return_delegation(inode, freeme, 0);
520 		nfs_free_delegation(freeme);
521 	}
522 	return status;
523 }
524 
525 /*
526  * Basic procedure for returning a delegation to the server
527  */
nfs_end_delegation_return(struct inode * inode,struct nfs_delegation * delegation,int issync)528 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
529 {
530 	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
531 	unsigned int mode = O_WRONLY | O_RDWR;
532 	int err = 0;
533 
534 	if (delegation == NULL)
535 		return 0;
536 
537 	if (!issync)
538 		mode |= O_NONBLOCK;
539 	/* Recall of any remaining application leases */
540 	err = break_lease(inode, mode);
541 
542 	while (err == 0) {
543 		if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
544 			break;
545 		err = nfs_delegation_claim_opens(inode, &delegation->stateid,
546 				delegation->type);
547 		if (!issync || err != -EAGAIN)
548 			break;
549 		/*
550 		 * Guard against state recovery
551 		 */
552 		err = nfs4_wait_clnt_recover(clp);
553 	}
554 
555 	if (err) {
556 		nfs_abort_delegation_return(delegation, clp, err);
557 		goto out;
558 	}
559 
560 	err = nfs_do_return_delegation(inode, delegation, issync);
561 out:
562 	/* Refcount matched in nfs_start_delegation_return_locked() */
563 	nfs_put_delegation(delegation);
564 	return err;
565 }
566 
nfs_delegation_need_return(struct nfs_delegation * delegation)567 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
568 {
569 	bool ret = false;
570 
571 	if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
572 		ret = true;
573 	else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
574 		struct inode *inode;
575 
576 		spin_lock(&delegation->lock);
577 		inode = delegation->inode;
578 		if (inode && list_empty(&NFS_I(inode)->open_files))
579 			ret = true;
580 		spin_unlock(&delegation->lock);
581 	}
582 	if (ret)
583 		clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
584 	if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
585 	    test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
586 	    test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
587 		ret = false;
588 
589 	return ret;
590 }
591 
nfs_server_return_marked_delegations(struct nfs_server * server,void __always_unused * data)592 static int nfs_server_return_marked_delegations(struct nfs_server *server,
593 		void __always_unused *data)
594 {
595 	struct nfs_delegation *delegation;
596 	struct nfs_delegation *prev;
597 	struct inode *inode;
598 	struct inode *place_holder = NULL;
599 	struct nfs_delegation *place_holder_deleg = NULL;
600 	int err = 0;
601 
602 restart:
603 	/*
604 	 * To avoid quadratic looping we hold a reference
605 	 * to an inode place_holder.  Each time we restart, we
606 	 * list delegation in the server from the delegations
607 	 * of that inode.
608 	 * prev is an RCU-protected pointer to a delegation which
609 	 * wasn't marked for return and might be a good choice for
610 	 * the next place_holder.
611 	 */
612 	prev = NULL;
613 	delegation = NULL;
614 	rcu_read_lock();
615 	if (place_holder)
616 		delegation = rcu_dereference(NFS_I(place_holder)->delegation);
617 	if (!delegation || delegation != place_holder_deleg)
618 		delegation = list_entry_rcu(server->delegations.next,
619 					    struct nfs_delegation, super_list);
620 	list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
621 		struct inode *to_put = NULL;
622 
623 		if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
624 			continue;
625 		if (!nfs_delegation_need_return(delegation)) {
626 			if (nfs4_is_valid_delegation(delegation, 0))
627 				prev = delegation;
628 			continue;
629 		}
630 
631 		if (prev) {
632 			struct inode *tmp = nfs_delegation_grab_inode(prev);
633 			if (tmp) {
634 				to_put = place_holder;
635 				place_holder = tmp;
636 				place_holder_deleg = prev;
637 			}
638 		}
639 
640 		inode = nfs_delegation_grab_inode(delegation);
641 		if (inode == NULL) {
642 			rcu_read_unlock();
643 			iput(to_put);
644 			goto restart;
645 		}
646 		delegation = nfs_start_delegation_return_locked(NFS_I(inode));
647 		rcu_read_unlock();
648 
649 		iput(to_put);
650 
651 		err = nfs_end_delegation_return(inode, delegation, 0);
652 		iput(inode);
653 		cond_resched();
654 		if (!err)
655 			goto restart;
656 		set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
657 		goto out;
658 	}
659 	rcu_read_unlock();
660 out:
661 	iput(place_holder);
662 	return err;
663 }
664 
nfs_server_clear_delayed_delegations(struct nfs_server * server)665 static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
666 {
667 	struct nfs_delegation *d;
668 	bool ret = false;
669 
670 	list_for_each_entry_rcu (d, &server->delegations, super_list) {
671 		if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
672 			continue;
673 		nfs_mark_return_delegation(server, d);
674 		clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags);
675 		ret = true;
676 	}
677 	return ret;
678 }
679 
nfs_client_clear_delayed_delegations(struct nfs_client * clp)680 static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
681 {
682 	struct nfs_server *server;
683 	bool ret = false;
684 
685 	if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))
686 		goto out;
687 	rcu_read_lock();
688 	list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
689 		if (nfs_server_clear_delayed_delegations(server))
690 			ret = true;
691 	}
692 	rcu_read_unlock();
693 out:
694 	return ret;
695 }
696 
697 /**
698  * nfs_client_return_marked_delegations - return previously marked delegations
699  * @clp: nfs_client to process
700  *
701  * Note that this function is designed to be called by the state
702  * manager thread. For this reason, it cannot flush the dirty data,
703  * since that could deadlock in case of a state recovery error.
704  *
705  * Returns zero on success, or a negative errno value.
706  */
nfs_client_return_marked_delegations(struct nfs_client * clp)707 int nfs_client_return_marked_delegations(struct nfs_client *clp)
708 {
709 	int err = nfs_client_for_each_server(
710 		clp, nfs_server_return_marked_delegations, NULL);
711 	if (err)
712 		return err;
713 	/* If a return was delayed, sleep to prevent hard looping */
714 	if (nfs_client_clear_delayed_delegations(clp))
715 		ssleep(1);
716 	return 0;
717 }
718 
719 /**
720  * nfs_inode_evict_delegation - return delegation, don't reclaim opens
721  * @inode: inode to process
722  *
723  * Does not protect against delegation reclaims, therefore really only safe
724  * to be called from nfs4_clear_inode(). Guaranteed to always free
725  * the delegation structure.
726  */
nfs_inode_evict_delegation(struct inode * inode)727 void nfs_inode_evict_delegation(struct inode *inode)
728 {
729 	struct nfs_delegation *delegation;
730 
731 	delegation = nfs_inode_detach_delegation(inode);
732 	if (delegation != NULL) {
733 		set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
734 		set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
735 		nfs_do_return_delegation(inode, delegation, 1);
736 		nfs_free_delegation(delegation);
737 	}
738 }
739 
740 /**
741  * nfs4_inode_return_delegation - synchronously return a delegation
742  * @inode: inode to process
743  *
744  * This routine will always flush any dirty data to disk on the
745  * assumption that if we need to return the delegation, then
746  * we should stop caching.
747  *
748  * Returns zero on success, or a negative errno value.
749  */
nfs4_inode_return_delegation(struct inode * inode)750 int nfs4_inode_return_delegation(struct inode *inode)
751 {
752 	struct nfs_inode *nfsi = NFS_I(inode);
753 	struct nfs_delegation *delegation;
754 
755 	delegation = nfs_start_delegation_return(nfsi);
756 	if (delegation != NULL) {
757 		/* Synchronous recall of any application leases */
758 		break_lease(inode, O_WRONLY | O_RDWR);
759 		if (S_ISREG(inode->i_mode))
760 			nfs_wb_all(inode);
761 		return nfs_end_delegation_return(inode, delegation, 1);
762 	}
763 	return 0;
764 }
765 
766 /**
767  * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
768  * @inode: inode to process
769  *
770  * This routine is called on file close in order to determine if the
771  * inode delegation needs to be returned immediately.
772  */
nfs4_inode_return_delegation_on_close(struct inode * inode)773 void nfs4_inode_return_delegation_on_close(struct inode *inode)
774 {
775 	struct nfs_delegation *delegation;
776 	struct nfs_delegation *ret = NULL;
777 
778 	if (!inode)
779 		return;
780 	rcu_read_lock();
781 	delegation = nfs4_get_valid_delegation(inode);
782 	if (!delegation)
783 		goto out;
784 	if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
785 	    atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
786 		spin_lock(&delegation->lock);
787 		if (delegation->inode &&
788 		    list_empty(&NFS_I(inode)->open_files) &&
789 		    !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
790 			clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
791 			/* Refcount matched in nfs_end_delegation_return() */
792 			ret = nfs_get_delegation(delegation);
793 		}
794 		spin_unlock(&delegation->lock);
795 		if (ret)
796 			nfs_clear_verifier_delegated(inode);
797 	}
798 out:
799 	rcu_read_unlock();
800 	nfs_end_delegation_return(inode, ret, 0);
801 }
802 
803 /**
804  * nfs4_inode_make_writeable
805  * @inode: pointer to inode
806  *
807  * Make the inode writeable by returning the delegation if necessary
808  *
809  * Returns zero on success, or a negative errno value.
810  */
nfs4_inode_make_writeable(struct inode * inode)811 int nfs4_inode_make_writeable(struct inode *inode)
812 {
813 	struct nfs_delegation *delegation;
814 
815 	rcu_read_lock();
816 	delegation = nfs4_get_valid_delegation(inode);
817 	if (delegation == NULL ||
818 	    (nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
819 	     (delegation->type & FMODE_WRITE))) {
820 		rcu_read_unlock();
821 		return 0;
822 	}
823 	rcu_read_unlock();
824 	return nfs4_inode_return_delegation(inode);
825 }
826 
nfs_mark_return_if_closed_delegation(struct nfs_server * server,struct nfs_delegation * delegation)827 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
828 		struct nfs_delegation *delegation)
829 {
830 	set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
831 	set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
832 }
833 
nfs_server_mark_return_all_delegations(struct nfs_server * server)834 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
835 {
836 	struct nfs_delegation *delegation;
837 	bool ret = false;
838 
839 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
840 		nfs_mark_return_delegation(server, delegation);
841 		ret = true;
842 	}
843 	return ret;
844 }
845 
nfs_client_mark_return_all_delegations(struct nfs_client * clp)846 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
847 {
848 	struct nfs_server *server;
849 
850 	rcu_read_lock();
851 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
852 		nfs_server_mark_return_all_delegations(server);
853 	rcu_read_unlock();
854 }
855 
nfs_delegation_run_state_manager(struct nfs_client * clp)856 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
857 {
858 	if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
859 		nfs4_schedule_state_manager(clp);
860 }
861 
862 /**
863  * nfs_expire_all_delegations
864  * @clp: client to process
865  *
866  */
nfs_expire_all_delegations(struct nfs_client * clp)867 void nfs_expire_all_delegations(struct nfs_client *clp)
868 {
869 	nfs_client_mark_return_all_delegations(clp);
870 	nfs_delegation_run_state_manager(clp);
871 }
872 
873 /**
874  * nfs_server_return_all_delegations - return delegations for one superblock
875  * @server: pointer to nfs_server to process
876  *
877  */
nfs_server_return_all_delegations(struct nfs_server * server)878 void nfs_server_return_all_delegations(struct nfs_server *server)
879 {
880 	struct nfs_client *clp = server->nfs_client;
881 	bool need_wait;
882 
883 	if (clp == NULL)
884 		return;
885 
886 	rcu_read_lock();
887 	need_wait = nfs_server_mark_return_all_delegations(server);
888 	rcu_read_unlock();
889 
890 	if (need_wait) {
891 		nfs4_schedule_state_manager(clp);
892 		nfs4_wait_clnt_recover(clp);
893 	}
894 }
895 
nfs_mark_return_unused_delegation_types(struct nfs_server * server,fmode_t flags)896 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
897 						 fmode_t flags)
898 {
899 	struct nfs_delegation *delegation;
900 
901 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
902 		if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
903 			continue;
904 		if (delegation->type & flags)
905 			nfs_mark_return_if_closed_delegation(server, delegation);
906 	}
907 }
908 
nfs_client_mark_return_unused_delegation_types(struct nfs_client * clp,fmode_t flags)909 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
910 							fmode_t flags)
911 {
912 	struct nfs_server *server;
913 
914 	rcu_read_lock();
915 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
916 		nfs_mark_return_unused_delegation_types(server, flags);
917 	rcu_read_unlock();
918 }
919 
nfs_revoke_delegation(struct inode * inode,const nfs4_stateid * stateid)920 static void nfs_revoke_delegation(struct inode *inode,
921 		const nfs4_stateid *stateid)
922 {
923 	struct nfs_delegation *delegation;
924 	nfs4_stateid tmp;
925 	bool ret = false;
926 
927 	rcu_read_lock();
928 	delegation = rcu_dereference(NFS_I(inode)->delegation);
929 	if (delegation == NULL)
930 		goto out;
931 	if (stateid == NULL) {
932 		nfs4_stateid_copy(&tmp, &delegation->stateid);
933 		stateid = &tmp;
934 	} else {
935 		if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
936 			goto out;
937 		spin_lock(&delegation->lock);
938 		if (stateid->seqid) {
939 			if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
940 				spin_unlock(&delegation->lock);
941 				goto out;
942 			}
943 			delegation->stateid.seqid = stateid->seqid;
944 		}
945 		spin_unlock(&delegation->lock);
946 	}
947 	nfs_mark_delegation_revoked(delegation);
948 	ret = true;
949 out:
950 	rcu_read_unlock();
951 	if (ret)
952 		nfs_inode_find_state_and_recover(inode, stateid);
953 }
954 
nfs_remove_bad_delegation(struct inode * inode,const nfs4_stateid * stateid)955 void nfs_remove_bad_delegation(struct inode *inode,
956 		const nfs4_stateid *stateid)
957 {
958 	nfs_revoke_delegation(inode, stateid);
959 }
960 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
961 
nfs_delegation_mark_returned(struct inode * inode,const nfs4_stateid * stateid)962 void nfs_delegation_mark_returned(struct inode *inode,
963 		const nfs4_stateid *stateid)
964 {
965 	struct nfs_delegation *delegation;
966 
967 	if (!inode)
968 		return;
969 
970 	rcu_read_lock();
971 	delegation = rcu_dereference(NFS_I(inode)->delegation);
972 	if (!delegation)
973 		goto out_rcu_unlock;
974 
975 	spin_lock(&delegation->lock);
976 	if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
977 		goto out_spin_unlock;
978 	if (stateid->seqid) {
979 		/* If delegation->stateid is newer, dont mark as returned */
980 		if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
981 			goto out_clear_returning;
982 		if (delegation->stateid.seqid != stateid->seqid)
983 			delegation->stateid.seqid = stateid->seqid;
984 	}
985 
986 	nfs_mark_delegation_revoked(delegation);
987 
988 out_clear_returning:
989 	clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
990 out_spin_unlock:
991 	spin_unlock(&delegation->lock);
992 out_rcu_unlock:
993 	rcu_read_unlock();
994 
995 	nfs_inode_find_state_and_recover(inode, stateid);
996 }
997 
998 /**
999  * nfs_expire_unused_delegation_types
1000  * @clp: client to process
1001  * @flags: delegation types to expire
1002  *
1003  */
nfs_expire_unused_delegation_types(struct nfs_client * clp,fmode_t flags)1004 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1005 {
1006 	nfs_client_mark_return_unused_delegation_types(clp, flags);
1007 	nfs_delegation_run_state_manager(clp);
1008 }
1009 
nfs_mark_return_unreferenced_delegations(struct nfs_server * server)1010 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1011 {
1012 	struct nfs_delegation *delegation;
1013 
1014 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1015 		if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
1016 			continue;
1017 		nfs_mark_return_if_closed_delegation(server, delegation);
1018 	}
1019 }
1020 
1021 /**
1022  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1023  * @clp: nfs_client to process
1024  *
1025  */
nfs_expire_unreferenced_delegations(struct nfs_client * clp)1026 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
1027 {
1028 	struct nfs_server *server;
1029 
1030 	rcu_read_lock();
1031 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1032 		nfs_mark_return_unreferenced_delegations(server);
1033 	rcu_read_unlock();
1034 
1035 	nfs_delegation_run_state_manager(clp);
1036 }
1037 
1038 /**
1039  * nfs_async_inode_return_delegation - asynchronously return a delegation
1040  * @inode: inode to process
1041  * @stateid: state ID information
1042  *
1043  * Returns zero on success, or a negative errno value.
1044  */
nfs_async_inode_return_delegation(struct inode * inode,const nfs4_stateid * stateid)1045 int nfs_async_inode_return_delegation(struct inode *inode,
1046 				      const nfs4_stateid *stateid)
1047 {
1048 	struct nfs_server *server = NFS_SERVER(inode);
1049 	struct nfs_client *clp = server->nfs_client;
1050 	struct nfs_delegation *delegation;
1051 
1052 	rcu_read_lock();
1053 	delegation = nfs4_get_valid_delegation(inode);
1054 	if (delegation == NULL)
1055 		goto out_enoent;
1056 	if (stateid != NULL &&
1057 	    !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1058 		goto out_enoent;
1059 	nfs_mark_return_delegation(server, delegation);
1060 	rcu_read_unlock();
1061 
1062 	/* If there are any application leases or delegations, recall them */
1063 	break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1064 
1065 	nfs_delegation_run_state_manager(clp);
1066 	return 0;
1067 out_enoent:
1068 	rcu_read_unlock();
1069 	return -ENOENT;
1070 }
1071 
1072 static struct inode *
nfs_delegation_find_inode_server(struct nfs_server * server,const struct nfs_fh * fhandle)1073 nfs_delegation_find_inode_server(struct nfs_server *server,
1074 				 const struct nfs_fh *fhandle)
1075 {
1076 	struct nfs_delegation *delegation;
1077 	struct super_block *freeme = NULL;
1078 	struct inode *res = NULL;
1079 
1080 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1081 		spin_lock(&delegation->lock);
1082 		if (delegation->inode != NULL &&
1083 		    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1084 		    nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1085 			if (nfs_sb_active(server->super)) {
1086 				freeme = server->super;
1087 				res = igrab(delegation->inode);
1088 			}
1089 			spin_unlock(&delegation->lock);
1090 			if (res != NULL)
1091 				return res;
1092 			if (freeme) {
1093 				rcu_read_unlock();
1094 				nfs_sb_deactive(freeme);
1095 				rcu_read_lock();
1096 			}
1097 			return ERR_PTR(-EAGAIN);
1098 		}
1099 		spin_unlock(&delegation->lock);
1100 	}
1101 	return ERR_PTR(-ENOENT);
1102 }
1103 
1104 /**
1105  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1106  * @clp: client state handle
1107  * @fhandle: filehandle from a delegation recall
1108  *
1109  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1110  * cannot be found.
1111  */
nfs_delegation_find_inode(struct nfs_client * clp,const struct nfs_fh * fhandle)1112 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1113 					const struct nfs_fh *fhandle)
1114 {
1115 	struct nfs_server *server;
1116 	struct inode *res;
1117 
1118 	rcu_read_lock();
1119 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1120 		res = nfs_delegation_find_inode_server(server, fhandle);
1121 		if (res != ERR_PTR(-ENOENT)) {
1122 			rcu_read_unlock();
1123 			return res;
1124 		}
1125 	}
1126 	rcu_read_unlock();
1127 	return ERR_PTR(-ENOENT);
1128 }
1129 
nfs_delegation_mark_reclaim_server(struct nfs_server * server)1130 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1131 {
1132 	struct nfs_delegation *delegation;
1133 
1134 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1135 		/*
1136 		 * If the delegation may have been admin revoked, then we
1137 		 * cannot reclaim it.
1138 		 */
1139 		if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1140 			continue;
1141 		set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1142 	}
1143 }
1144 
1145 /**
1146  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1147  * @clp: nfs_client to process
1148  *
1149  */
nfs_delegation_mark_reclaim(struct nfs_client * clp)1150 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1151 {
1152 	struct nfs_server *server;
1153 
1154 	rcu_read_lock();
1155 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1156 		nfs_delegation_mark_reclaim_server(server);
1157 	rcu_read_unlock();
1158 }
1159 
nfs_server_reap_unclaimed_delegations(struct nfs_server * server,void __always_unused * data)1160 static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1161 		void __always_unused *data)
1162 {
1163 	struct nfs_delegation *delegation;
1164 	struct inode *inode;
1165 restart:
1166 	rcu_read_lock();
1167 restart_locked:
1168 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1169 		if (test_bit(NFS_DELEGATION_INODE_FREEING,
1170 					&delegation->flags) ||
1171 		    test_bit(NFS_DELEGATION_RETURNING,
1172 					&delegation->flags) ||
1173 		    test_bit(NFS_DELEGATION_NEED_RECLAIM,
1174 					&delegation->flags) == 0)
1175 			continue;
1176 		inode = nfs_delegation_grab_inode(delegation);
1177 		if (inode == NULL)
1178 			goto restart_locked;
1179 		delegation = nfs_start_delegation_return_locked(NFS_I(inode));
1180 		rcu_read_unlock();
1181 		if (delegation != NULL) {
1182 			if (nfs_detach_delegation(NFS_I(inode), delegation,
1183 						server) != NULL)
1184 				nfs_free_delegation(delegation);
1185 			/* Match nfs_start_delegation_return_locked */
1186 			nfs_put_delegation(delegation);
1187 		}
1188 		iput(inode);
1189 		cond_resched();
1190 		goto restart;
1191 	}
1192 	rcu_read_unlock();
1193 	return 0;
1194 }
1195 
1196 /**
1197  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1198  * @clp: nfs_client to process
1199  *
1200  */
nfs_delegation_reap_unclaimed(struct nfs_client * clp)1201 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1202 {
1203 	nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
1204 			NULL);
1205 }
1206 
nfs4_server_rebooted(const struct nfs_client * clp)1207 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1208 {
1209 	return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1210 				BIT(NFS4CLNT_LEASE_EXPIRED) |
1211 				BIT(NFS4CLNT_SESSION_RESET))) != 0;
1212 }
1213 
nfs_mark_test_expired_delegation(struct nfs_server * server,struct nfs_delegation * delegation)1214 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1215 	    struct nfs_delegation *delegation)
1216 {
1217 	if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1218 		return;
1219 	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1220 	set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1221 	set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1222 }
1223 
nfs_inode_mark_test_expired_delegation(struct nfs_server * server,struct inode * inode)1224 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1225 		struct inode *inode)
1226 {
1227 	struct nfs_delegation *delegation;
1228 
1229 	rcu_read_lock();
1230 	delegation = rcu_dereference(NFS_I(inode)->delegation);
1231 	if (delegation)
1232 		nfs_mark_test_expired_delegation(server, delegation);
1233 	rcu_read_unlock();
1234 
1235 }
1236 
nfs_delegation_mark_test_expired_server(struct nfs_server * server)1237 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1238 {
1239 	struct nfs_delegation *delegation;
1240 
1241 	list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1242 		nfs_mark_test_expired_delegation(server, delegation);
1243 }
1244 
1245 /**
1246  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1247  * @clp: nfs_client to process
1248  *
1249  * Iterates through all the delegations associated with this server and
1250  * marks them as needing to be checked for validity.
1251  */
nfs_mark_test_expired_all_delegations(struct nfs_client * clp)1252 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1253 {
1254 	struct nfs_server *server;
1255 
1256 	rcu_read_lock();
1257 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1258 		nfs_delegation_mark_test_expired_server(server);
1259 	rcu_read_unlock();
1260 }
1261 
1262 /**
1263  * nfs_test_expired_all_delegations - test all delegations for a client
1264  * @clp: nfs_client to process
1265  *
1266  * Helper for handling "recallable state revoked" status from server.
1267  */
nfs_test_expired_all_delegations(struct nfs_client * clp)1268 void nfs_test_expired_all_delegations(struct nfs_client *clp)
1269 {
1270 	nfs_mark_test_expired_all_delegations(clp);
1271 	nfs4_schedule_state_manager(clp);
1272 }
1273 
1274 static void
nfs_delegation_test_free_expired(struct inode * inode,nfs4_stateid * stateid,const struct cred * cred)1275 nfs_delegation_test_free_expired(struct inode *inode,
1276 		nfs4_stateid *stateid,
1277 		const struct cred *cred)
1278 {
1279 	struct nfs_server *server = NFS_SERVER(inode);
1280 	const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1281 	int status;
1282 
1283 	if (!cred)
1284 		return;
1285 	status = ops->test_and_free_expired(server, stateid, cred);
1286 	if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1287 		nfs_remove_bad_delegation(inode, stateid);
1288 }
1289 
nfs_server_reap_expired_delegations(struct nfs_server * server,void __always_unused * data)1290 static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1291 		void __always_unused *data)
1292 {
1293 	struct nfs_delegation *delegation;
1294 	struct inode *inode;
1295 	const struct cred *cred;
1296 	nfs4_stateid stateid;
1297 restart:
1298 	rcu_read_lock();
1299 restart_locked:
1300 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1301 		if (test_bit(NFS_DELEGATION_INODE_FREEING,
1302 					&delegation->flags) ||
1303 		    test_bit(NFS_DELEGATION_RETURNING,
1304 					&delegation->flags) ||
1305 		    test_bit(NFS_DELEGATION_TEST_EXPIRED,
1306 					&delegation->flags) == 0)
1307 			continue;
1308 		inode = nfs_delegation_grab_inode(delegation);
1309 		if (inode == NULL)
1310 			goto restart_locked;
1311 		spin_lock(&delegation->lock);
1312 		cred = get_cred_rcu(delegation->cred);
1313 		nfs4_stateid_copy(&stateid, &delegation->stateid);
1314 		spin_unlock(&delegation->lock);
1315 		clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1316 		rcu_read_unlock();
1317 		nfs_delegation_test_free_expired(inode, &stateid, cred);
1318 		put_cred(cred);
1319 		if (!nfs4_server_rebooted(server->nfs_client)) {
1320 			iput(inode);
1321 			cond_resched();
1322 			goto restart;
1323 		}
1324 		nfs_inode_mark_test_expired_delegation(server,inode);
1325 		iput(inode);
1326 		return -EAGAIN;
1327 	}
1328 	rcu_read_unlock();
1329 	return 0;
1330 }
1331 
1332 /**
1333  * nfs_reap_expired_delegations - reap expired delegations
1334  * @clp: nfs_client to process
1335  *
1336  * Iterates through all the delegations associated with this server and
1337  * checks if they have may have been revoked. This function is usually
1338  * expected to be called in cases where the server may have lost its
1339  * lease.
1340  */
nfs_reap_expired_delegations(struct nfs_client * clp)1341 void nfs_reap_expired_delegations(struct nfs_client *clp)
1342 {
1343 	nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
1344 			NULL);
1345 }
1346 
nfs_inode_find_delegation_state_and_recover(struct inode * inode,const nfs4_stateid * stateid)1347 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1348 		const nfs4_stateid *stateid)
1349 {
1350 	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1351 	struct nfs_delegation *delegation;
1352 	bool found = false;
1353 
1354 	rcu_read_lock();
1355 	delegation = rcu_dereference(NFS_I(inode)->delegation);
1356 	if (delegation &&
1357 	    nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
1358 	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1359 		nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1360 		found = true;
1361 	}
1362 	rcu_read_unlock();
1363 	if (found)
1364 		nfs4_schedule_state_manager(clp);
1365 }
1366 
1367 /**
1368  * nfs_delegations_present - check for existence of delegations
1369  * @clp: client state handle
1370  *
1371  * Returns one if there are any nfs_delegation structures attached
1372  * to this nfs_client.
1373  */
nfs_delegations_present(struct nfs_client * clp)1374 int nfs_delegations_present(struct nfs_client *clp)
1375 {
1376 	struct nfs_server *server;
1377 	int ret = 0;
1378 
1379 	rcu_read_lock();
1380 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1381 		if (!list_empty(&server->delegations)) {
1382 			ret = 1;
1383 			break;
1384 		}
1385 	rcu_read_unlock();
1386 	return ret;
1387 }
1388 
1389 /**
1390  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1391  * @dst: stateid to refresh
1392  * @inode: inode to check
1393  *
1394  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1395  * that matches our delegation stateid. Otherwise "false" is returned.
1396  */
nfs4_refresh_delegation_stateid(nfs4_stateid * dst,struct inode * inode)1397 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1398 {
1399 	struct nfs_delegation *delegation;
1400 	bool ret = false;
1401 	if (!inode)
1402 		goto out;
1403 
1404 	rcu_read_lock();
1405 	delegation = rcu_dereference(NFS_I(inode)->delegation);
1406 	if (delegation != NULL &&
1407 	    nfs4_stateid_match_other(dst, &delegation->stateid) &&
1408 	    nfs4_stateid_is_newer(&delegation->stateid, dst) &&
1409 	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1410 		dst->seqid = delegation->stateid.seqid;
1411 		ret = true;
1412 	}
1413 	rcu_read_unlock();
1414 out:
1415 	return ret;
1416 }
1417 
1418 /**
1419  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1420  * @inode: inode to check
1421  * @flags: delegation type requirement
1422  * @dst: stateid data structure to fill in
1423  * @cred: optional argument to retrieve credential
1424  *
1425  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1426  * otherwise "false" is returned.
1427  */
nfs4_copy_delegation_stateid(struct inode * inode,fmode_t flags,nfs4_stateid * dst,const struct cred ** cred)1428 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1429 		nfs4_stateid *dst, const struct cred **cred)
1430 {
1431 	struct nfs_inode *nfsi = NFS_I(inode);
1432 	struct nfs_delegation *delegation;
1433 	bool ret = false;
1434 
1435 	flags &= FMODE_READ|FMODE_WRITE;
1436 	rcu_read_lock();
1437 	delegation = rcu_dereference(nfsi->delegation);
1438 	if (!delegation)
1439 		goto out;
1440 	spin_lock(&delegation->lock);
1441 	ret = nfs4_is_valid_delegation(delegation, flags);
1442 	if (ret) {
1443 		nfs4_stateid_copy(dst, &delegation->stateid);
1444 		nfs_mark_delegation_referenced(delegation);
1445 		if (cred)
1446 			*cred = get_cred(delegation->cred);
1447 	}
1448 	spin_unlock(&delegation->lock);
1449 out:
1450 	rcu_read_unlock();
1451 	return ret;
1452 }
1453 
1454 /**
1455  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1456  * @inode: inode to check
1457  *
1458  * This function checks the number of outstanding writes to the file
1459  * against the delegation 'space_limit' field to see if
1460  * the spec requires us to flush the file on close.
1461  */
nfs4_delegation_flush_on_close(const struct inode * inode)1462 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1463 {
1464 	struct nfs_inode *nfsi = NFS_I(inode);
1465 	struct nfs_delegation *delegation;
1466 	bool ret = true;
1467 
1468 	rcu_read_lock();
1469 	delegation = rcu_dereference(nfsi->delegation);
1470 	if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1471 		goto out;
1472 	if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1473 		ret = false;
1474 out:
1475 	rcu_read_unlock();
1476 	return ret;
1477 }
1478 
1479 module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
1480