1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/sunrpc/cache.c
4 *
5 * Generic code for various authentication-related caches
6 * used by sunrpc clients and servers.
7 *
8 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
9 */
10
11 #include <linux/types.h>
12 #include <linux/fs.h>
13 #include <linux/file.h>
14 #include <linux/slab.h>
15 #include <linux/signal.h>
16 #include <linux/sched.h>
17 #include <linux/kmod.h>
18 #include <linux/list.h>
19 #include <linux/module.h>
20 #include <linux/ctype.h>
21 #include <linux/string_helpers.h>
22 #include <linux/uaccess.h>
23 #include <linux/poll.h>
24 #include <linux/seq_file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/net.h>
27 #include <linux/workqueue.h>
28 #include <linux/mutex.h>
29 #include <linux/pagemap.h>
30 #include <asm/ioctls.h>
31 #include <linux/sunrpc/types.h>
32 #include <linux/sunrpc/cache.h>
33 #include <linux/sunrpc/stats.h>
34 #include <linux/sunrpc/rpc_pipe_fs.h>
35 #include <trace/events/sunrpc.h>
36
37 #include "netns.h"
38 #include "fail.h"
39
40 #define RPCDBG_FACILITY RPCDBG_CACHE
41
42 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
43 static void cache_revisit_request(struct cache_head *item);
44
45 static void cache_init(struct cache_head *h, struct cache_detail *detail)
46 {
47 time64_t now = seconds_since_boot();
48 INIT_HLIST_NODE(&h->cache_list);
49 h->flags = 0;
50 kref_init(&h->ref);
51 h->expiry_time = now + CACHE_NEW_EXPIRY;
52 if (now <= detail->flush_time)
53 /* ensure it isn't already expired */
54 now = detail->flush_time + 1;
55 h->last_refresh = now;
56 }
57
58 static void cache_fresh_unlocked(struct cache_head *head,
59 struct cache_detail *detail);
60
61 static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
62 struct cache_head *key,
63 int hash)
64 {
65 struct hlist_head *head = &detail->hash_table[hash];
66 struct cache_head *tmp;
67
68 rcu_read_lock();
69 hlist_for_each_entry_rcu(tmp, head, cache_list) {
70 if (!detail->match(tmp, key))
71 continue;
72 if (test_bit(CACHE_VALID, &tmp->flags) &&
73 cache_is_expired(detail, tmp))
74 continue;
75 tmp = cache_get_rcu(tmp);
76 rcu_read_unlock();
77 return tmp;
78 }
79 rcu_read_unlock();
80 return NULL;
81 }
82
83 static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
84 struct cache_detail *cd)
85 {
86 /* Must be called under cd->hash_lock */
87 hlist_del_init_rcu(&ch->cache_list);
88 set_bit(CACHE_CLEANED, &ch->flags);
89 cd->entries --;
90 }
91
92 static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
93 struct cache_detail *cd)
94 {
95 cache_fresh_unlocked(ch, cd);
96 cache_put(ch, cd);
97 }
98
99 static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
100 struct cache_head *key,
101 int hash)
102 {
103 struct cache_head *new, *tmp, *freeme = NULL;
104 struct hlist_head *head = &detail->hash_table[hash];
105
106 new = detail->alloc();
107 if (!new)
108 return NULL;
109 /* must fully initialise 'new', else
110 * we might get lose if we need to
111 * cache_put it soon.
112 */
113 cache_init(new, detail);
114 detail->init(new, key);
115
116 spin_lock(&detail->hash_lock);
117
118 /* check if entry appeared while we slept */
119 hlist_for_each_entry_rcu(tmp, head, cache_list,
120 lockdep_is_held(&detail->hash_lock)) {
121 if (!detail->match(tmp, key))
122 continue;
123 if (test_bit(CACHE_VALID, &tmp->flags) &&
124 cache_is_expired(detail, tmp)) {
125 sunrpc_begin_cache_remove_entry(tmp, detail);
126 trace_cache_entry_expired(detail, tmp);
127 freeme = tmp;
128 break;
129 }
130 cache_get(tmp);
131 spin_unlock(&detail->hash_lock);
132 cache_put(new, detail);
133 return tmp;
134 }
135
136 hlist_add_head_rcu(&new->cache_list, head);
137 detail->entries++;
138 cache_get(new);
139 spin_unlock(&detail->hash_lock);
140
141 if (freeme)
142 sunrpc_end_cache_remove_entry(freeme, detail);
143 return new;
144 }
145
146 struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
147 struct cache_head *key, int hash)
148 {
149 struct cache_head *ret;
150
151 ret = sunrpc_cache_find_rcu(detail, key, hash);
152 if (ret)
153 return ret;
154 /* Didn't find anything, insert an empty entry */
155 return sunrpc_cache_add_entry(detail, key, hash);
156 }
157 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
158
159 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
160
161 static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
162 struct cache_detail *detail)
163 {
164 time64_t now = seconds_since_boot();
165 if (now <= detail->flush_time)
166 /* ensure it isn't immediately treated as expired */
167 now = detail->flush_time + 1;
168 head->expiry_time = expiry;
169 head->last_refresh = now;
170 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
171 set_bit(CACHE_VALID, &head->flags);
172 }
173
174 static void cache_fresh_unlocked(struct cache_head *head,
175 struct cache_detail *detail)
176 {
177 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
178 cache_revisit_request(head);
179 cache_dequeue(detail, head);
180 }
181 }
182
183 static void cache_make_negative(struct cache_detail *detail,
184 struct cache_head *h)
185 {
186 set_bit(CACHE_NEGATIVE, &h->flags);
187 trace_cache_entry_make_negative(detail, h);
188 }
189
190 static void cache_entry_update(struct cache_detail *detail,
191 struct cache_head *h,
192 struct cache_head *new)
193 {
194 if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
195 detail->update(h, new);
196 trace_cache_entry_update(detail, h);
197 } else {
198 cache_make_negative(detail, h);
199 }
200 }
201
202 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
203 struct cache_head *new, struct cache_head *old, int hash)
204 {
205 /* The 'old' entry is to be replaced by 'new'.
206 * If 'old' is not VALID, we update it directly,
207 * otherwise we need to replace it
208 */
209 struct cache_head *tmp;
210
211 if (!test_bit(CACHE_VALID, &old->flags)) {
212 spin_lock(&detail->hash_lock);
213 if (!test_bit(CACHE_VALID, &old->flags)) {
214 cache_entry_update(detail, old, new);
215 cache_fresh_locked(old, new->expiry_time, detail);
216 spin_unlock(&detail->hash_lock);
217 cache_fresh_unlocked(old, detail);
218 return old;
219 }
220 spin_unlock(&detail->hash_lock);
221 }
222 /* We need to insert a new entry */
223 tmp = detail->alloc();
224 if (!tmp) {
225 cache_put(old, detail);
226 return NULL;
227 }
228 cache_init(tmp, detail);
229 detail->init(tmp, old);
230
231 spin_lock(&detail->hash_lock);
232 cache_entry_update(detail, tmp, new);
233 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
234 detail->entries++;
235 cache_get(tmp);
236 cache_fresh_locked(tmp, new->expiry_time, detail);
237 cache_fresh_locked(old, 0, detail);
238 spin_unlock(&detail->hash_lock);
239 cache_fresh_unlocked(tmp, detail);
240 cache_fresh_unlocked(old, detail);
241 cache_put(old, detail);
242 return tmp;
243 }
244 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
245
246 static inline int cache_is_valid(struct cache_head *h)
247 {
248 if (!test_bit(CACHE_VALID, &h->flags))
249 return -EAGAIN;
250 else {
251 /* entry is valid */
252 if (test_bit(CACHE_NEGATIVE, &h->flags))
253 return -ENOENT;
254 else {
255 /*
256 * In combination with write barrier in
257 * sunrpc_cache_update, ensures that anyone
258 * using the cache entry after this sees the
259 * updated contents:
260 */
261 smp_rmb();
262 return 0;
263 }
264 }
265 }
266
267 static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
268 {
269 int rv;
270
271 spin_lock(&detail->hash_lock);
272 rv = cache_is_valid(h);
273 if (rv == -EAGAIN) {
274 cache_make_negative(detail, h);
275 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
276 detail);
277 rv = -ENOENT;
278 }
279 spin_unlock(&detail->hash_lock);
280 cache_fresh_unlocked(h, detail);
281 return rv;
282 }
283
284 /*
285 * This is the generic cache management routine for all
286 * the authentication caches.
287 * It checks the currency of a cache item and will (later)
288 * initiate an upcall to fill it if needed.
289 *
290 *
291 * Returns 0 if the cache_head can be used, or cache_puts it and returns
292 * -EAGAIN if upcall is pending and request has been queued
293 * -ETIMEDOUT if upcall failed or request could not be queue or
294 * upcall completed but item is still invalid (implying that
295 * the cache item has been replaced with a newer one).
296 * -ENOENT if cache entry was negative
297 */
298 int cache_check(struct cache_detail *detail,
299 struct cache_head *h, struct cache_req *rqstp)
300 {
301 int rv;
302 time64_t refresh_age, age;
303
304 /* First decide return status as best we can */
305 rv = cache_is_valid(h);
306
307 /* now see if we want to start an upcall */
308 refresh_age = (h->expiry_time - h->last_refresh);
309 age = seconds_since_boot() - h->last_refresh;
310
311 if (rqstp == NULL) {
312 if (rv == -EAGAIN)
313 rv = -ENOENT;
314 } else if (rv == -EAGAIN ||
315 (h->expiry_time != 0 && age > refresh_age/2)) {
316 dprintk("RPC: Want update, refage=%lld, age=%lld\n",
317 refresh_age, age);
318 switch (detail->cache_upcall(detail, h)) {
319 case -EINVAL:
320 rv = try_to_negate_entry(detail, h);
321 break;
322 case -EAGAIN:
323 cache_fresh_unlocked(h, detail);
324 break;
325 }
326 }
327
328 if (rv == -EAGAIN) {
329 if (!cache_defer_req(rqstp, h)) {
330 /*
331 * Request was not deferred; handle it as best
332 * we can ourselves:
333 */
334 rv = cache_is_valid(h);
335 if (rv == -EAGAIN)
336 rv = -ETIMEDOUT;
337 }
338 }
339 if (rv)
340 cache_put(h, detail);
341 return rv;
342 }
343 EXPORT_SYMBOL_GPL(cache_check);
344
345 /*
346 * caches need to be periodically cleaned.
347 * For this we maintain a list of cache_detail and
348 * a current pointer into that list and into the table
349 * for that entry.
350 *
351 * Each time cache_clean is called it finds the next non-empty entry
352 * in the current table and walks the list in that entry
353 * looking for entries that can be removed.
354 *
355 * An entry gets removed if:
356 * - The expiry is before current time
357 * - The last_refresh time is before the flush_time for that cache
358 *
359 * later we might drop old entries with non-NEVER expiry if that table
360 * is getting 'full' for some definition of 'full'
361 *
362 * The question of "how often to scan a table" is an interesting one
363 * and is answered in part by the use of the "nextcheck" field in the
364 * cache_detail.
365 * When a scan of a table begins, the nextcheck field is set to a time
366 * that is well into the future.
367 * While scanning, if an expiry time is found that is earlier than the
368 * current nextcheck time, nextcheck is set to that expiry time.
369 * If the flush_time is ever set to a time earlier than the nextcheck
370 * time, the nextcheck time is then set to that flush_time.
371 *
372 * A table is then only scanned if the current time is at least
373 * the nextcheck time.
374 *
375 */
376
377 static LIST_HEAD(cache_list);
378 static DEFINE_SPINLOCK(cache_list_lock);
379 static struct cache_detail *current_detail;
380 static int current_index;
381
382 static void do_cache_clean(struct work_struct *work);
383 static struct delayed_work cache_cleaner;
384
385 void sunrpc_init_cache_detail(struct cache_detail *cd)
386 {
387 spin_lock_init(&cd->hash_lock);
388 INIT_LIST_HEAD(&cd->queue);
389 spin_lock(&cache_list_lock);
390 cd->nextcheck = 0;
391 cd->entries = 0;
392 atomic_set(&cd->writers, 0);
393 cd->last_close = 0;
394 cd->last_warn = -1;
395 list_add(&cd->others, &cache_list);
396 spin_unlock(&cache_list_lock);
397
398 /* start the cleaning process */
399 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
400 }
401 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
402
403 void sunrpc_destroy_cache_detail(struct cache_detail *cd)
404 {
405 cache_purge(cd);
406 spin_lock(&cache_list_lock);
407 spin_lock(&cd->hash_lock);
408 if (current_detail == cd)
409 current_detail = NULL;
410 list_del_init(&cd->others);
411 spin_unlock(&cd->hash_lock);
412 spin_unlock(&cache_list_lock);
413 if (list_empty(&cache_list)) {
414 /* module must be being unloaded so its safe to kill the worker */
415 cancel_delayed_work_sync(&cache_cleaner);
416 }
417 }
418 EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
419
420 /* clean cache tries to find something to clean
421 * and cleans it.
422 * It returns 1 if it cleaned something,
423 * 0 if it didn't find anything this time
424 * -1 if it fell off the end of the list.
425 */
426 static int cache_clean(void)
427 {
428 int rv = 0;
429 struct list_head *next;
430
431 spin_lock(&cache_list_lock);
432
433 /* find a suitable table if we don't already have one */
434 while (current_detail == NULL ||
435 current_index >= current_detail->hash_size) {
436 if (current_detail)
437 next = current_detail->others.next;
438 else
439 next = cache_list.next;
440 if (next == &cache_list) {
441 current_detail = NULL;
442 spin_unlock(&cache_list_lock);
443 return -1;
444 }
445 current_detail = list_entry(next, struct cache_detail, others);
446 if (current_detail->nextcheck > seconds_since_boot())
447 current_index = current_detail->hash_size;
448 else {
449 current_index = 0;
450 current_detail->nextcheck = seconds_since_boot()+30*60;
451 }
452 }
453
454 /* find a non-empty bucket in the table */
455 while (current_detail &&
456 current_index < current_detail->hash_size &&
457 hlist_empty(¤t_detail->hash_table[current_index]))
458 current_index++;
459
460 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
461
462 if (current_detail && current_index < current_detail->hash_size) {
463 struct cache_head *ch = NULL;
464 struct cache_detail *d;
465 struct hlist_head *head;
466 struct hlist_node *tmp;
467
468 spin_lock(¤t_detail->hash_lock);
469
470 /* Ok, now to clean this strand */
471
472 head = ¤t_detail->hash_table[current_index];
473 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
474 if (current_detail->nextcheck > ch->expiry_time)
475 current_detail->nextcheck = ch->expiry_time+1;
476 if (!cache_is_expired(current_detail, ch))
477 continue;
478
479 sunrpc_begin_cache_remove_entry(ch, current_detail);
480 trace_cache_entry_expired(current_detail, ch);
481 rv = 1;
482 break;
483 }
484
485 spin_unlock(¤t_detail->hash_lock);
486 d = current_detail;
487 if (!ch)
488 current_index ++;
489 spin_unlock(&cache_list_lock);
490 if (ch)
491 sunrpc_end_cache_remove_entry(ch, d);
492 } else
493 spin_unlock(&cache_list_lock);
494
495 return rv;
496 }
497
498 /*
499 * We want to regularly clean the cache, so we need to schedule some work ...
500 */
501 static void do_cache_clean(struct work_struct *work)
502 {
503 int delay;
504
505 if (list_empty(&cache_list))
506 return;
507
508 if (cache_clean() == -1)
509 delay = round_jiffies_relative(30*HZ);
510 else
511 delay = 5;
512
513 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, delay);
514 }
515
516
517 /*
518 * Clean all caches promptly. This just calls cache_clean
519 * repeatedly until we are sure that every cache has had a chance to
520 * be fully cleaned
521 */
522 void cache_flush(void)
523 {
524 while (cache_clean() != -1)
525 cond_resched();
526 while (cache_clean() != -1)
527 cond_resched();
528 }
529 EXPORT_SYMBOL_GPL(cache_flush);
530
531 void cache_purge(struct cache_detail *detail)
532 {
533 struct cache_head *ch = NULL;
534 struct hlist_head *head = NULL;
535 int i = 0;
536
537 spin_lock(&detail->hash_lock);
538 if (!detail->entries) {
539 spin_unlock(&detail->hash_lock);
540 return;
541 }
542
543 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
544 for (i = 0; i < detail->hash_size; i++) {
545 head = &detail->hash_table[i];
546 while (!hlist_empty(head)) {
547 ch = hlist_entry(head->first, struct cache_head,
548 cache_list);
549 sunrpc_begin_cache_remove_entry(ch, detail);
550 spin_unlock(&detail->hash_lock);
551 sunrpc_end_cache_remove_entry(ch, detail);
552 spin_lock(&detail->hash_lock);
553 }
554 }
555 spin_unlock(&detail->hash_lock);
556 }
557 EXPORT_SYMBOL_GPL(cache_purge);
558
559
560 /*
561 * Deferral and Revisiting of Requests.
562 *
563 * If a cache lookup finds a pending entry, we
564 * need to defer the request and revisit it later.
565 * All deferred requests are stored in a hash table,
566 * indexed by "struct cache_head *".
567 * As it may be wasteful to store a whole request
568 * structure, we allow the request to provide a
569 * deferred form, which must contain a
570 * 'struct cache_deferred_req'
571 * This cache_deferred_req contains a method to allow
572 * it to be revisited when cache info is available
573 */
574
575 #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
576 #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
577
578 #define DFR_MAX 300 /* ??? */
579
580 static DEFINE_SPINLOCK(cache_defer_lock);
581 static LIST_HEAD(cache_defer_list);
582 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
583 static int cache_defer_cnt;
584
585 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
586 {
587 hlist_del_init(&dreq->hash);
588 if (!list_empty(&dreq->recent)) {
589 list_del_init(&dreq->recent);
590 cache_defer_cnt--;
591 }
592 }
593
594 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
595 {
596 int hash = DFR_HASH(item);
597
598 INIT_LIST_HEAD(&dreq->recent);
599 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
600 }
601
602 static void setup_deferral(struct cache_deferred_req *dreq,
603 struct cache_head *item,
604 int count_me)
605 {
606
607 dreq->item = item;
608
609 spin_lock(&cache_defer_lock);
610
611 __hash_deferred_req(dreq, item);
612
613 if (count_me) {
614 cache_defer_cnt++;
615 list_add(&dreq->recent, &cache_defer_list);
616 }
617
618 spin_unlock(&cache_defer_lock);
619
620 }
621
622 struct thread_deferred_req {
623 struct cache_deferred_req handle;
624 struct completion completion;
625 };
626
627 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
628 {
629 struct thread_deferred_req *dr =
630 container_of(dreq, struct thread_deferred_req, handle);
631 complete(&dr->completion);
632 }
633
634 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
635 {
636 struct thread_deferred_req sleeper;
637 struct cache_deferred_req *dreq = &sleeper.handle;
638
639 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
640 dreq->revisit = cache_restart_thread;
641
642 setup_deferral(dreq, item, 0);
643
644 if (!test_bit(CACHE_PENDING, &item->flags) ||
645 wait_for_completion_interruptible_timeout(
646 &sleeper.completion, req->thread_wait) <= 0) {
647 /* The completion wasn't completed, so we need
648 * to clean up
649 */
650 spin_lock(&cache_defer_lock);
651 if (!hlist_unhashed(&sleeper.handle.hash)) {
652 __unhash_deferred_req(&sleeper.handle);
653 spin_unlock(&cache_defer_lock);
654 } else {
655 /* cache_revisit_request already removed
656 * this from the hash table, but hasn't
657 * called ->revisit yet. It will very soon
658 * and we need to wait for it.
659 */
660 spin_unlock(&cache_defer_lock);
661 wait_for_completion(&sleeper.completion);
662 }
663 }
664 }
665
666 static void cache_limit_defers(void)
667 {
668 /* Make sure we haven't exceed the limit of allowed deferred
669 * requests.
670 */
671 struct cache_deferred_req *discard = NULL;
672
673 if (cache_defer_cnt <= DFR_MAX)
674 return;
675
676 spin_lock(&cache_defer_lock);
677
678 /* Consider removing either the first or the last */
679 if (cache_defer_cnt > DFR_MAX) {
680 if (get_random_u32_below(2))
681 discard = list_entry(cache_defer_list.next,
682 struct cache_deferred_req, recent);
683 else
684 discard = list_entry(cache_defer_list.prev,
685 struct cache_deferred_req, recent);
686 __unhash_deferred_req(discard);
687 }
688 spin_unlock(&cache_defer_lock);
689 if (discard)
690 discard->revisit(discard, 1);
691 }
692
693 #if IS_ENABLED(CONFIG_FAIL_SUNRPC)
694 static inline bool cache_defer_immediately(void)
695 {
696 return !fail_sunrpc.ignore_cache_wait &&
697 should_fail(&fail_sunrpc.attr, 1);
698 }
699 #else
700 static inline bool cache_defer_immediately(void)
701 {
702 return false;
703 }
704 #endif
705
706 /* Return true if and only if a deferred request is queued. */
707 static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
708 {
709 struct cache_deferred_req *dreq;
710
711 if (!cache_defer_immediately()) {
712 cache_wait_req(req, item);
713 if (!test_bit(CACHE_PENDING, &item->flags))
714 return false;
715 }
716
717 dreq = req->defer(req);
718 if (dreq == NULL)
719 return false;
720 setup_deferral(dreq, item, 1);
721 if (!test_bit(CACHE_PENDING, &item->flags))
722 /* Bit could have been cleared before we managed to
723 * set up the deferral, so need to revisit just in case
724 */
725 cache_revisit_request(item);
726
727 cache_limit_defers();
728 return true;
729 }
730
731 static void cache_revisit_request(struct cache_head *item)
732 {
733 struct cache_deferred_req *dreq;
734 struct list_head pending;
735 struct hlist_node *tmp;
736 int hash = DFR_HASH(item);
737
738 INIT_LIST_HEAD(&pending);
739 spin_lock(&cache_defer_lock);
740
741 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
742 if (dreq->item == item) {
743 __unhash_deferred_req(dreq);
744 list_add(&dreq->recent, &pending);
745 }
746
747 spin_unlock(&cache_defer_lock);
748
749 while (!list_empty(&pending)) {
750 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
751 list_del_init(&dreq->recent);
752 dreq->revisit(dreq, 0);
753 }
754 }
755
756 void cache_clean_deferred(void *owner)
757 {
758 struct cache_deferred_req *dreq, *tmp;
759 struct list_head pending;
760
761
762 INIT_LIST_HEAD(&pending);
763 spin_lock(&cache_defer_lock);
764
765 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
766 if (dreq->owner == owner) {
767 __unhash_deferred_req(dreq);
768 list_add(&dreq->recent, &pending);
769 }
770 }
771 spin_unlock(&cache_defer_lock);
772
773 while (!list_empty(&pending)) {
774 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
775 list_del_init(&dreq->recent);
776 dreq->revisit(dreq, 1);
777 }
778 }
779
780 /*
781 * communicate with user-space
782 *
783 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
784 * On read, you get a full request, or block.
785 * On write, an update request is processed.
786 * Poll works if anything to read, and always allows write.
787 *
788 * Implemented by linked list of requests. Each open file has
789 * a ->private that also exists in this list. New requests are added
790 * to the end and may wakeup and preceding readers.
791 * New readers are added to the head. If, on read, an item is found with
792 * CACHE_UPCALLING clear, we free it from the list.
793 *
794 */
795
796 static DEFINE_SPINLOCK(queue_lock);
797
798 struct cache_queue {
799 struct list_head list;
800 int reader; /* if 0, then request */
801 };
802 struct cache_request {
803 struct cache_queue q;
804 struct cache_head *item;
805 char * buf;
806 int len;
807 int readers;
808 };
809 struct cache_reader {
810 struct cache_queue q;
811 int offset; /* if non-0, we have a refcnt on next request */
812 };
813
814 static int cache_request(struct cache_detail *detail,
815 struct cache_request *crq)
816 {
817 char *bp = crq->buf;
818 int len = PAGE_SIZE;
819
820 detail->cache_request(detail, crq->item, &bp, &len);
821 if (len < 0)
822 return -E2BIG;
823 return PAGE_SIZE - len;
824 }
825
826 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
827 loff_t *ppos, struct cache_detail *cd)
828 {
829 struct cache_reader *rp = filp->private_data;
830 struct cache_request *rq;
831 struct inode *inode = file_inode(filp);
832 int err;
833
834 if (count == 0)
835 return 0;
836
837 inode_lock(inode); /* protect against multiple concurrent
838 * readers on this file */
839 again:
840 spin_lock(&queue_lock);
841 /* need to find next request */
842 while (rp->q.list.next != &cd->queue &&
843 list_entry(rp->q.list.next, struct cache_queue, list)
844 ->reader) {
845 struct list_head *next = rp->q.list.next;
846 list_move(&rp->q.list, next);
847 }
848 if (rp->q.list.next == &cd->queue) {
849 spin_unlock(&queue_lock);
850 inode_unlock(inode);
851 WARN_ON_ONCE(rp->offset);
852 return 0;
853 }
854 rq = container_of(rp->q.list.next, struct cache_request, q.list);
855 WARN_ON_ONCE(rq->q.reader);
856 if (rp->offset == 0)
857 rq->readers++;
858 spin_unlock(&queue_lock);
859
860 if (rq->len == 0) {
861 err = cache_request(cd, rq);
862 if (err < 0)
863 goto out;
864 rq->len = err;
865 }
866
867 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
868 err = -EAGAIN;
869 spin_lock(&queue_lock);
870 list_move(&rp->q.list, &rq->q.list);
871 spin_unlock(&queue_lock);
872 } else {
873 if (rp->offset + count > rq->len)
874 count = rq->len - rp->offset;
875 err = -EFAULT;
876 if (copy_to_user(buf, rq->buf + rp->offset, count))
877 goto out;
878 rp->offset += count;
879 if (rp->offset >= rq->len) {
880 rp->offset = 0;
881 spin_lock(&queue_lock);
882 list_move(&rp->q.list, &rq->q.list);
883 spin_unlock(&queue_lock);
884 }
885 err = 0;
886 }
887 out:
888 if (rp->offset == 0) {
889 /* need to release rq */
890 spin_lock(&queue_lock);
891 rq->readers--;
892 if (rq->readers == 0 &&
893 !test_bit(CACHE_PENDING, &rq->item->flags)) {
894 list_del(&rq->q.list);
895 spin_unlock(&queue_lock);
896 cache_put(rq->item, cd);
897 kfree(rq->buf);
898 kfree(rq);
899 } else
900 spin_unlock(&queue_lock);
901 }
902 if (err == -EAGAIN)
903 goto again;
904 inode_unlock(inode);
905 return err ? err : count;
906 }
907
908 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
909 size_t count, struct cache_detail *cd)
910 {
911 ssize_t ret;
912
913 if (count == 0)
914 return -EINVAL;
915 if (copy_from_user(kaddr, buf, count))
916 return -EFAULT;
917 kaddr[count] = '\0';
918 ret = cd->cache_parse(cd, kaddr, count);
919 if (!ret)
920 ret = count;
921 return ret;
922 }
923
924 static ssize_t cache_downcall(struct address_space *mapping,
925 const char __user *buf,
926 size_t count, struct cache_detail *cd)
927 {
928 char *write_buf;
929 ssize_t ret = -ENOMEM;
930
931 if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
932 ret = -EINVAL;
933 goto out;
934 }
935
936 write_buf = kvmalloc(count + 1, GFP_KERNEL);
937 if (!write_buf)
938 goto out;
939
940 ret = cache_do_downcall(write_buf, buf, count, cd);
941 kvfree(write_buf);
942 out:
943 return ret;
944 }
945
946 static ssize_t cache_write(struct file *filp, const char __user *buf,
947 size_t count, loff_t *ppos,
948 struct cache_detail *cd)
949 {
950 struct address_space *mapping = filp->f_mapping;
951 struct inode *inode = file_inode(filp);
952 ssize_t ret = -EINVAL;
953
954 if (!cd->cache_parse)
955 goto out;
956
957 inode_lock(inode);
958 ret = cache_downcall(mapping, buf, count, cd);
959 inode_unlock(inode);
960 out:
961 return ret;
962 }
963
964 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
965
966 static __poll_t cache_poll(struct file *filp, poll_table *wait,
967 struct cache_detail *cd)
968 {
969 __poll_t mask;
970 struct cache_reader *rp = filp->private_data;
971 struct cache_queue *cq;
972
973 poll_wait(filp, &queue_wait, wait);
974
975 /* alway allow write */
976 mask = EPOLLOUT | EPOLLWRNORM;
977
978 if (!rp)
979 return mask;
980
981 spin_lock(&queue_lock);
982
983 for (cq= &rp->q; &cq->list != &cd->queue;
984 cq = list_entry(cq->list.next, struct cache_queue, list))
985 if (!cq->reader) {
986 mask |= EPOLLIN | EPOLLRDNORM;
987 break;
988 }
989 spin_unlock(&queue_lock);
990 return mask;
991 }
992
993 static int cache_ioctl(struct inode *ino, struct file *filp,
994 unsigned int cmd, unsigned long arg,
995 struct cache_detail *cd)
996 {
997 int len = 0;
998 struct cache_reader *rp = filp->private_data;
999 struct cache_queue *cq;
1000
1001 if (cmd != FIONREAD || !rp)
1002 return -EINVAL;
1003
1004 spin_lock(&queue_lock);
1005
1006 /* only find the length remaining in current request,
1007 * or the length of the next request
1008 */
1009 for (cq= &rp->q; &cq->list != &cd->queue;
1010 cq = list_entry(cq->list.next, struct cache_queue, list))
1011 if (!cq->reader) {
1012 struct cache_request *cr =
1013 container_of(cq, struct cache_request, q);
1014 len = cr->len - rp->offset;
1015 break;
1016 }
1017 spin_unlock(&queue_lock);
1018
1019 return put_user(len, (int __user *)arg);
1020 }
1021
1022 static int cache_open(struct inode *inode, struct file *filp,
1023 struct cache_detail *cd)
1024 {
1025 struct cache_reader *rp = NULL;
1026
1027 if (!cd || !try_module_get(cd->owner))
1028 return -EACCES;
1029 nonseekable_open(inode, filp);
1030 if (filp->f_mode & FMODE_READ) {
1031 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1032 if (!rp) {
1033 module_put(cd->owner);
1034 return -ENOMEM;
1035 }
1036 rp->offset = 0;
1037 rp->q.reader = 1;
1038
1039 spin_lock(&queue_lock);
1040 list_add(&rp->q.list, &cd->queue);
1041 spin_unlock(&queue_lock);
1042 }
1043 if (filp->f_mode & FMODE_WRITE)
1044 atomic_inc(&cd->writers);
1045 filp->private_data = rp;
1046 return 0;
1047 }
1048
1049 static int cache_release(struct inode *inode, struct file *filp,
1050 struct cache_detail *cd)
1051 {
1052 struct cache_reader *rp = filp->private_data;
1053
1054 if (rp) {
1055 spin_lock(&queue_lock);
1056 if (rp->offset) {
1057 struct cache_queue *cq;
1058 for (cq= &rp->q; &cq->list != &cd->queue;
1059 cq = list_entry(cq->list.next, struct cache_queue, list))
1060 if (!cq->reader) {
1061 container_of(cq, struct cache_request, q)
1062 ->readers--;
1063 break;
1064 }
1065 rp->offset = 0;
1066 }
1067 list_del(&rp->q.list);
1068 spin_unlock(&queue_lock);
1069
1070 filp->private_data = NULL;
1071 kfree(rp);
1072
1073 }
1074 if (filp->f_mode & FMODE_WRITE) {
1075 atomic_dec(&cd->writers);
1076 cd->last_close = seconds_since_boot();
1077 }
1078 module_put(cd->owner);
1079 return 0;
1080 }
1081
1082
1083
1084 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1085 {
1086 struct cache_queue *cq, *tmp;
1087 struct cache_request *cr;
1088 struct list_head dequeued;
1089
1090 INIT_LIST_HEAD(&dequeued);
1091 spin_lock(&queue_lock);
1092 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1093 if (!cq->reader) {
1094 cr = container_of(cq, struct cache_request, q);
1095 if (cr->item != ch)
1096 continue;
1097 if (test_bit(CACHE_PENDING, &ch->flags))
1098 /* Lost a race and it is pending again */
1099 break;
1100 if (cr->readers != 0)
1101 continue;
1102 list_move(&cr->q.list, &dequeued);
1103 }
1104 spin_unlock(&queue_lock);
1105 while (!list_empty(&dequeued)) {
1106 cr = list_entry(dequeued.next, struct cache_request, q.list);
1107 list_del(&cr->q.list);
1108 cache_put(cr->item, detail);
1109 kfree(cr->buf);
1110 kfree(cr);
1111 }
1112 }
1113
1114 /*
1115 * Support routines for text-based upcalls.
1116 * Fields are separated by spaces.
1117 * Fields are either mangled to quote space tab newline slosh with slosh
1118 * or a hexified with a leading \x
1119 * Record is terminated with newline.
1120 *
1121 */
1122
1123 void qword_add(char **bpp, int *lp, char *str)
1124 {
1125 char *bp = *bpp;
1126 int len = *lp;
1127 int ret;
1128
1129 if (len < 0) return;
1130
1131 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1132 if (ret >= len) {
1133 bp += len;
1134 len = -1;
1135 } else {
1136 bp += ret;
1137 len -= ret;
1138 *bp++ = ' ';
1139 len--;
1140 }
1141 *bpp = bp;
1142 *lp = len;
1143 }
1144 EXPORT_SYMBOL_GPL(qword_add);
1145
1146 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1147 {
1148 char *bp = *bpp;
1149 int len = *lp;
1150
1151 if (len < 0) return;
1152
1153 if (len > 2) {
1154 *bp++ = '\\';
1155 *bp++ = 'x';
1156 len -= 2;
1157 while (blen && len >= 2) {
1158 bp = hex_byte_pack(bp, *buf++);
1159 len -= 2;
1160 blen--;
1161 }
1162 }
1163 if (blen || len<1) len = -1;
1164 else {
1165 *bp++ = ' ';
1166 len--;
1167 }
1168 *bpp = bp;
1169 *lp = len;
1170 }
1171 EXPORT_SYMBOL_GPL(qword_addhex);
1172
1173 static void warn_no_listener(struct cache_detail *detail)
1174 {
1175 if (detail->last_warn != detail->last_close) {
1176 detail->last_warn = detail->last_close;
1177 if (detail->warn_no_listener)
1178 detail->warn_no_listener(detail, detail->last_close != 0);
1179 }
1180 }
1181
1182 static bool cache_listeners_exist(struct cache_detail *detail)
1183 {
1184 if (atomic_read(&detail->writers))
1185 return true;
1186 if (detail->last_close == 0)
1187 /* This cache was never opened */
1188 return false;
1189 if (detail->last_close < seconds_since_boot() - 30)
1190 /*
1191 * We allow for the possibility that someone might
1192 * restart a userspace daemon without restarting the
1193 * server; but after 30 seconds, we give up.
1194 */
1195 return false;
1196 return true;
1197 }
1198
1199 /*
1200 * register an upcall request to user-space and queue it up for read() by the
1201 * upcall daemon.
1202 *
1203 * Each request is at most one page long.
1204 */
1205 static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1206 {
1207 char *buf;
1208 struct cache_request *crq;
1209 int ret = 0;
1210
1211 if (test_bit(CACHE_CLEANED, &h->flags))
1212 /* Too late to make an upcall */
1213 return -EAGAIN;
1214
1215 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1216 if (!buf)
1217 return -EAGAIN;
1218
1219 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1220 if (!crq) {
1221 kfree(buf);
1222 return -EAGAIN;
1223 }
1224
1225 crq->q.reader = 0;
1226 crq->buf = buf;
1227 crq->len = 0;
1228 crq->readers = 0;
1229 spin_lock(&queue_lock);
1230 if (test_bit(CACHE_PENDING, &h->flags)) {
1231 crq->item = cache_get(h);
1232 list_add_tail(&crq->q.list, &detail->queue);
1233 trace_cache_entry_upcall(detail, h);
1234 } else
1235 /* Lost a race, no longer PENDING, so don't enqueue */
1236 ret = -EAGAIN;
1237 spin_unlock(&queue_lock);
1238 wake_up(&queue_wait);
1239 if (ret == -EAGAIN) {
1240 kfree(buf);
1241 kfree(crq);
1242 }
1243 return ret;
1244 }
1245
1246 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1247 {
1248 if (test_and_set_bit(CACHE_PENDING, &h->flags))
1249 return 0;
1250 return cache_pipe_upcall(detail, h);
1251 }
1252 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1253
1254 int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1255 struct cache_head *h)
1256 {
1257 if (!cache_listeners_exist(detail)) {
1258 warn_no_listener(detail);
1259 trace_cache_entry_no_listener(detail, h);
1260 return -EINVAL;
1261 }
1262 return sunrpc_cache_pipe_upcall(detail, h);
1263 }
1264 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1265
1266 /*
1267 * parse a message from user-space and pass it
1268 * to an appropriate cache
1269 * Messages are, like requests, separated into fields by
1270 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1271 *
1272 * Message is
1273 * reply cachename expiry key ... content....
1274 *
1275 * key and content are both parsed by cache
1276 */
1277
1278 int qword_get(char **bpp, char *dest, int bufsize)
1279 {
1280 /* return bytes copied, or -1 on error */
1281 char *bp = *bpp;
1282 int len = 0;
1283
1284 while (*bp == ' ') bp++;
1285
1286 if (bp[0] == '\\' && bp[1] == 'x') {
1287 /* HEX STRING */
1288 bp += 2;
1289 while (len < bufsize - 1) {
1290 int h, l;
1291
1292 h = hex_to_bin(bp[0]);
1293 if (h < 0)
1294 break;
1295
1296 l = hex_to_bin(bp[1]);
1297 if (l < 0)
1298 break;
1299
1300 *dest++ = (h << 4) | l;
1301 bp += 2;
1302 len++;
1303 }
1304 } else {
1305 /* text with \nnn octal quoting */
1306 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1307 if (*bp == '\\' &&
1308 isodigit(bp[1]) && (bp[1] <= '3') &&
1309 isodigit(bp[2]) &&
1310 isodigit(bp[3])) {
1311 int byte = (*++bp -'');
1312 bp++;
1313 byte = (byte << 3) | (*bp++ - '');
1314 byte = (byte << 3) | (*bp++ - '');
1315 *dest++ = byte;
1316 len++;
1317 } else {
1318 *dest++ = *bp++;
1319 len++;
1320 }
1321 }
1322 }
1323
1324 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1325 return -1;
1326 while (*bp == ' ') bp++;
1327 *bpp = bp;
1328 *dest = '\0';
1329 return len;
1330 }
1331 EXPORT_SYMBOL_GPL(qword_get);
1332
1333
1334 /*
1335 * support /proc/net/rpc/$CACHENAME/content
1336 * as a seqfile.
1337 * We call ->cache_show passing NULL for the item to
1338 * get a header, then pass each real item in the cache
1339 */
1340
1341 static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1342 {
1343 loff_t n = *pos;
1344 unsigned int hash, entry;
1345 struct cache_head *ch;
1346 struct cache_detail *cd = m->private;
1347
1348 if (!n--)
1349 return SEQ_START_TOKEN;
1350 hash = n >> 32;
1351 entry = n & ((1LL<<32) - 1);
1352
1353 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1354 if (!entry--)
1355 return ch;
1356 n &= ~((1LL<<32) - 1);
1357 do {
1358 hash++;
1359 n += 1LL<<32;
1360 } while(hash < cd->hash_size &&
1361 hlist_empty(&cd->hash_table[hash]));
1362 if (hash >= cd->hash_size)
1363 return NULL;
1364 *pos = n+1;
1365 return hlist_entry_safe(rcu_dereference_raw(
1366 hlist_first_rcu(&cd->hash_table[hash])),
1367 struct cache_head, cache_list);
1368 }
1369
1370 static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1371 {
1372 struct cache_head *ch = p;
1373 int hash = (*pos >> 32);
1374 struct cache_detail *cd = m->private;
1375
1376 if (p == SEQ_START_TOKEN)
1377 hash = 0;
1378 else if (ch->cache_list.next == NULL) {
1379 hash++;
1380 *pos += 1LL<<32;
1381 } else {
1382 ++*pos;
1383 return hlist_entry_safe(rcu_dereference_raw(
1384 hlist_next_rcu(&ch->cache_list)),
1385 struct cache_head, cache_list);
1386 }
1387 *pos &= ~((1LL<<32) - 1);
1388 while (hash < cd->hash_size &&
1389 hlist_empty(&cd->hash_table[hash])) {
1390 hash++;
1391 *pos += 1LL<<32;
1392 }
1393 if (hash >= cd->hash_size)
1394 return NULL;
1395 ++*pos;
1396 return hlist_entry_safe(rcu_dereference_raw(
1397 hlist_first_rcu(&cd->hash_table[hash])),
1398 struct cache_head, cache_list);
1399 }
1400
1401 void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1402 __acquires(RCU)
1403 {
1404 rcu_read_lock();
1405 return __cache_seq_start(m, pos);
1406 }
1407 EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1408
1409 void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1410 {
1411 return cache_seq_next(file, p, pos);
1412 }
1413 EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1414
1415 void cache_seq_stop_rcu(struct seq_file *m, void *p)
1416 __releases(RCU)
1417 {
1418 rcu_read_unlock();
1419 }
1420 EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1421
1422 static int c_show(struct seq_file *m, void *p)
1423 {
1424 struct cache_head *cp = p;
1425 struct cache_detail *cd = m->private;
1426
1427 if (p == SEQ_START_TOKEN)
1428 return cd->cache_show(m, cd, NULL);
1429
1430 ifdebug(CACHE)
1431 seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1432 convert_to_wallclock(cp->expiry_time),
1433 kref_read(&cp->ref), cp->flags);
1434 cache_get(cp);
1435 if (cache_check(cd, cp, NULL))
1436 /* cache_check does a cache_put on failure */
1437 seq_puts(m, "# ");
1438 else {
1439 if (cache_is_expired(cd, cp))
1440 seq_puts(m, "# ");
1441 cache_put(cp, cd);
1442 }
1443
1444 return cd->cache_show(m, cd, cp);
1445 }
1446
1447 static const struct seq_operations cache_content_op = {
1448 .start = cache_seq_start_rcu,
1449 .next = cache_seq_next_rcu,
1450 .stop = cache_seq_stop_rcu,
1451 .show = c_show,
1452 };
1453
1454 static int content_open(struct inode *inode, struct file *file,
1455 struct cache_detail *cd)
1456 {
1457 struct seq_file *seq;
1458 int err;
1459
1460 if (!cd || !try_module_get(cd->owner))
1461 return -EACCES;
1462
1463 err = seq_open(file, &cache_content_op);
1464 if (err) {
1465 module_put(cd->owner);
1466 return err;
1467 }
1468
1469 seq = file->private_data;
1470 seq->private = cd;
1471 return 0;
1472 }
1473
1474 static int content_release(struct inode *inode, struct file *file,
1475 struct cache_detail *cd)
1476 {
1477 int ret = seq_release(inode, file);
1478 module_put(cd->owner);
1479 return ret;
1480 }
1481
1482 static int open_flush(struct inode *inode, struct file *file,
1483 struct cache_detail *cd)
1484 {
1485 if (!cd || !try_module_get(cd->owner))
1486 return -EACCES;
1487 return nonseekable_open(inode, file);
1488 }
1489
1490 static int release_flush(struct inode *inode, struct file *file,
1491 struct cache_detail *cd)
1492 {
1493 module_put(cd->owner);
1494 return 0;
1495 }
1496
1497 static ssize_t read_flush(struct file *file, char __user *buf,
1498 size_t count, loff_t *ppos,
1499 struct cache_detail *cd)
1500 {
1501 char tbuf[22];
1502 size_t len;
1503
1504 len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1505 convert_to_wallclock(cd->flush_time));
1506 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1507 }
1508
1509 static ssize_t write_flush(struct file *file, const char __user *buf,
1510 size_t count, loff_t *ppos,
1511 struct cache_detail *cd)
1512 {
1513 char tbuf[20];
1514 char *ep;
1515 time64_t now;
1516
1517 if (*ppos || count > sizeof(tbuf)-1)
1518 return -EINVAL;
1519 if (copy_from_user(tbuf, buf, count))
1520 return -EFAULT;
1521 tbuf[count] = 0;
1522 simple_strtoul(tbuf, &ep, 0);
1523 if (*ep && *ep != '\n')
1524 return -EINVAL;
1525 /* Note that while we check that 'buf' holds a valid number,
1526 * we always ignore the value and just flush everything.
1527 * Making use of the number leads to races.
1528 */
1529
1530 now = seconds_since_boot();
1531 /* Always flush everything, so behave like cache_purge()
1532 * Do this by advancing flush_time to the current time,
1533 * or by one second if it has already reached the current time.
1534 * Newly added cache entries will always have ->last_refresh greater
1535 * that ->flush_time, so they don't get flushed prematurely.
1536 */
1537
1538 if (cd->flush_time >= now)
1539 now = cd->flush_time + 1;
1540
1541 cd->flush_time = now;
1542 cd->nextcheck = now;
1543 cache_flush();
1544
1545 if (cd->flush)
1546 cd->flush();
1547
1548 *ppos += count;
1549 return count;
1550 }
1551
1552 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1553 size_t count, loff_t *ppos)
1554 {
1555 struct cache_detail *cd = pde_data(file_inode(filp));
1556
1557 return cache_read(filp, buf, count, ppos, cd);
1558 }
1559
1560 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1561 size_t count, loff_t *ppos)
1562 {
1563 struct cache_detail *cd = pde_data(file_inode(filp));
1564
1565 return cache_write(filp, buf, count, ppos, cd);
1566 }
1567
1568 static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1569 {
1570 struct cache_detail *cd = pde_data(file_inode(filp));
1571
1572 return cache_poll(filp, wait, cd);
1573 }
1574
1575 static long cache_ioctl_procfs(struct file *filp,
1576 unsigned int cmd, unsigned long arg)
1577 {
1578 struct inode *inode = file_inode(filp);
1579 struct cache_detail *cd = pde_data(inode);
1580
1581 return cache_ioctl(inode, filp, cmd, arg, cd);
1582 }
1583
1584 static int cache_open_procfs(struct inode *inode, struct file *filp)
1585 {
1586 struct cache_detail *cd = pde_data(inode);
1587
1588 return cache_open(inode, filp, cd);
1589 }
1590
1591 static int cache_release_procfs(struct inode *inode, struct file *filp)
1592 {
1593 struct cache_detail *cd = pde_data(inode);
1594
1595 return cache_release(inode, filp, cd);
1596 }
1597
1598 static const struct proc_ops cache_channel_proc_ops = {
1599 .proc_lseek = no_llseek,
1600 .proc_read = cache_read_procfs,
1601 .proc_write = cache_write_procfs,
1602 .proc_poll = cache_poll_procfs,
1603 .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1604 .proc_open = cache_open_procfs,
1605 .proc_release = cache_release_procfs,
1606 };
1607
1608 static int content_open_procfs(struct inode *inode, struct file *filp)
1609 {
1610 struct cache_detail *cd = pde_data(inode);
1611
1612 return content_open(inode, filp, cd);
1613 }
1614
1615 static int content_release_procfs(struct inode *inode, struct file *filp)
1616 {
1617 struct cache_detail *cd = pde_data(inode);
1618
1619 return content_release(inode, filp, cd);
1620 }
1621
1622 static const struct proc_ops content_proc_ops = {
1623 .proc_open = content_open_procfs,
1624 .proc_read = seq_read,
1625 .proc_lseek = seq_lseek,
1626 .proc_release = content_release_procfs,
1627 };
1628
1629 static int open_flush_procfs(struct inode *inode, struct file *filp)
1630 {
1631 struct cache_detail *cd = pde_data(inode);
1632
1633 return open_flush(inode, filp, cd);
1634 }
1635
1636 static int release_flush_procfs(struct inode *inode, struct file *filp)
1637 {
1638 struct cache_detail *cd = pde_data(inode);
1639
1640 return release_flush(inode, filp, cd);
1641 }
1642
1643 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1644 size_t count, loff_t *ppos)
1645 {
1646 struct cache_detail *cd = pde_data(file_inode(filp));
1647
1648 return read_flush(filp, buf, count, ppos, cd);
1649 }
1650
1651 static ssize_t write_flush_procfs(struct file *filp,
1652 const char __user *buf,
1653 size_t count, loff_t *ppos)
1654 {
1655 struct cache_detail *cd = pde_data(file_inode(filp));
1656
1657 return write_flush(filp, buf, count, ppos, cd);
1658 }
1659
1660 static const struct proc_ops cache_flush_proc_ops = {
1661 .proc_open = open_flush_procfs,
1662 .proc_read = read_flush_procfs,
1663 .proc_write = write_flush_procfs,
1664 .proc_release = release_flush_procfs,
1665 .proc_lseek = no_llseek,
1666 };
1667
1668 static void remove_cache_proc_entries(struct cache_detail *cd)
1669 {
1670 if (cd->procfs) {
1671 proc_remove(cd->procfs);
1672 cd->procfs = NULL;
1673 }
1674 }
1675
1676 #ifdef CONFIG_PROC_FS
1677 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1678 {
1679 struct proc_dir_entry *p;
1680 struct sunrpc_net *sn;
1681
1682 sn = net_generic(net, sunrpc_net_id);
1683 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1684 if (cd->procfs == NULL)
1685 goto out_nomem;
1686
1687 p = proc_create_data("flush", S_IFREG | 0600,
1688 cd->procfs, &cache_flush_proc_ops, cd);
1689 if (p == NULL)
1690 goto out_nomem;
1691
1692 if (cd->cache_request || cd->cache_parse) {
1693 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1694 &cache_channel_proc_ops, cd);
1695 if (p == NULL)
1696 goto out_nomem;
1697 }
1698 if (cd->cache_show) {
1699 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1700 &content_proc_ops, cd);
1701 if (p == NULL)
1702 goto out_nomem;
1703 }
1704 return 0;
1705 out_nomem:
1706 remove_cache_proc_entries(cd);
1707 return -ENOMEM;
1708 }
1709 #else /* CONFIG_PROC_FS */
1710 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1711 {
1712 return 0;
1713 }
1714 #endif
1715
1716 void __init cache_initialize(void)
1717 {
1718 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1719 }
1720
1721 int cache_register_net(struct cache_detail *cd, struct net *net)
1722 {
1723 int ret;
1724
1725 sunrpc_init_cache_detail(cd);
1726 ret = create_cache_proc_entries(cd, net);
1727 if (ret)
1728 sunrpc_destroy_cache_detail(cd);
1729 return ret;
1730 }
1731 EXPORT_SYMBOL_GPL(cache_register_net);
1732
1733 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1734 {
1735 remove_cache_proc_entries(cd);
1736 sunrpc_destroy_cache_detail(cd);
1737 }
1738 EXPORT_SYMBOL_GPL(cache_unregister_net);
1739
1740 struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1741 {
1742 struct cache_detail *cd;
1743 int i;
1744
1745 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1746 if (cd == NULL)
1747 return ERR_PTR(-ENOMEM);
1748
1749 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1750 GFP_KERNEL);
1751 if (cd->hash_table == NULL) {
1752 kfree(cd);
1753 return ERR_PTR(-ENOMEM);
1754 }
1755
1756 for (i = 0; i < cd->hash_size; i++)
1757 INIT_HLIST_HEAD(&cd->hash_table[i]);
1758 cd->net = net;
1759 return cd;
1760 }
1761 EXPORT_SYMBOL_GPL(cache_create_net);
1762
1763 void cache_destroy_net(struct cache_detail *cd, struct net *net)
1764 {
1765 kfree(cd->hash_table);
1766 kfree(cd);
1767 }
1768 EXPORT_SYMBOL_GPL(cache_destroy_net);
1769
1770 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1771 size_t count, loff_t *ppos)
1772 {
1773 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1774
1775 return cache_read(filp, buf, count, ppos, cd);
1776 }
1777
1778 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1779 size_t count, loff_t *ppos)
1780 {
1781 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1782
1783 return cache_write(filp, buf, count, ppos, cd);
1784 }
1785
1786 static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1787 {
1788 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1789
1790 return cache_poll(filp, wait, cd);
1791 }
1792
1793 static long cache_ioctl_pipefs(struct file *filp,
1794 unsigned int cmd, unsigned long arg)
1795 {
1796 struct inode *inode = file_inode(filp);
1797 struct cache_detail *cd = RPC_I(inode)->private;
1798
1799 return cache_ioctl(inode, filp, cmd, arg, cd);
1800 }
1801
1802 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1803 {
1804 struct cache_detail *cd = RPC_I(inode)->private;
1805
1806 return cache_open(inode, filp, cd);
1807 }
1808
1809 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1810 {
1811 struct cache_detail *cd = RPC_I(inode)->private;
1812
1813 return cache_release(inode, filp, cd);
1814 }
1815
1816 const struct file_operations cache_file_operations_pipefs = {
1817 .owner = THIS_MODULE,
1818 .llseek = no_llseek,
1819 .read = cache_read_pipefs,
1820 .write = cache_write_pipefs,
1821 .poll = cache_poll_pipefs,
1822 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1823 .open = cache_open_pipefs,
1824 .release = cache_release_pipefs,
1825 };
1826
1827 static int content_open_pipefs(struct inode *inode, struct file *filp)
1828 {
1829 struct cache_detail *cd = RPC_I(inode)->private;
1830
1831 return content_open(inode, filp, cd);
1832 }
1833
1834 static int content_release_pipefs(struct inode *inode, struct file *filp)
1835 {
1836 struct cache_detail *cd = RPC_I(inode)->private;
1837
1838 return content_release(inode, filp, cd);
1839 }
1840
1841 const struct file_operations content_file_operations_pipefs = {
1842 .open = content_open_pipefs,
1843 .read = seq_read,
1844 .llseek = seq_lseek,
1845 .release = content_release_pipefs,
1846 };
1847
1848 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1849 {
1850 struct cache_detail *cd = RPC_I(inode)->private;
1851
1852 return open_flush(inode, filp, cd);
1853 }
1854
1855 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1856 {
1857 struct cache_detail *cd = RPC_I(inode)->private;
1858
1859 return release_flush(inode, filp, cd);
1860 }
1861
1862 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1863 size_t count, loff_t *ppos)
1864 {
1865 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1866
1867 return read_flush(filp, buf, count, ppos, cd);
1868 }
1869
1870 static ssize_t write_flush_pipefs(struct file *filp,
1871 const char __user *buf,
1872 size_t count, loff_t *ppos)
1873 {
1874 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1875
1876 return write_flush(filp, buf, count, ppos, cd);
1877 }
1878
1879 const struct file_operations cache_flush_operations_pipefs = {
1880 .open = open_flush_pipefs,
1881 .read = read_flush_pipefs,
1882 .write = write_flush_pipefs,
1883 .release = release_flush_pipefs,
1884 .llseek = no_llseek,
1885 };
1886
1887 int sunrpc_cache_register_pipefs(struct dentry *parent,
1888 const char *name, umode_t umode,
1889 struct cache_detail *cd)
1890 {
1891 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1892 if (IS_ERR(dir))
1893 return PTR_ERR(dir);
1894 cd->pipefs = dir;
1895 return 0;
1896 }
1897 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1898
1899 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1900 {
1901 if (cd->pipefs) {
1902 rpc_remove_cache_dir(cd->pipefs);
1903 cd->pipefs = NULL;
1904 }
1905 }
1906 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1907
1908 void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1909 {
1910 spin_lock(&cd->hash_lock);
1911 if (!hlist_unhashed(&h->cache_list)){
1912 sunrpc_begin_cache_remove_entry(h, cd);
1913 spin_unlock(&cd->hash_lock);
1914 sunrpc_end_cache_remove_entry(h, cd);
1915 } else
1916 spin_unlock(&cd->hash_lock);
1917 }
1918 EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);
1919
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