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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 "netns.h"
36
37#define RPCDBG_FACILITY RPCDBG_CACHE
38
39static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
40static void cache_revisit_request(struct cache_head *item);
41static bool cache_listeners_exist(struct cache_detail *detail);
42
43static void cache_init(struct cache_head *h, struct cache_detail *detail)
44{
45 time_t now = seconds_since_boot();
46 INIT_HLIST_NODE(&h->cache_list);
47 h->flags = 0;
48 kref_init(&h->ref);
49 h->expiry_time = now + CACHE_NEW_EXPIRY;
50 if (now <= detail->flush_time)
51 /* ensure it isn't already expired */
52 now = detail->flush_time + 1;
53 h->last_refresh = now;
54}
55
56static inline int cache_is_valid(struct cache_head *h);
57static void cache_fresh_locked(struct cache_head *head, time_t expiry,
58 struct cache_detail *detail);
59static void cache_fresh_unlocked(struct cache_head *head,
60 struct cache_detail *detail);
61
62static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
63 struct cache_head *key,
64 int hash)
65{
66 struct hlist_head *head = &detail->hash_table[hash];
67 struct cache_head *tmp;
68
69 rcu_read_lock();
70 hlist_for_each_entry_rcu(tmp, head, cache_list) {
71 if (detail->match(tmp, key)) {
72 if (cache_is_expired(detail, tmp))
73 continue;
74 tmp = cache_get_rcu(tmp);
75 rcu_read_unlock();
76 return tmp;
77 }
78 }
79 rcu_read_unlock();
80 return NULL;
81}
82
83static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
84 struct cache_head *key,
85 int hash)
86{
87 struct cache_head *new, *tmp, *freeme = NULL;
88 struct hlist_head *head = &detail->hash_table[hash];
89
90 new = detail->alloc();
91 if (!new)
92 return NULL;
93 /* must fully initialise 'new', else
94 * we might get lose if we need to
95 * cache_put it soon.
96 */
97 cache_init(new, detail);
98 detail->init(new, key);
99
100 spin_lock(&detail->hash_lock);
101
102 /* check if entry appeared while we slept */
103 hlist_for_each_entry_rcu(tmp, head, cache_list) {
104 if (detail->match(tmp, key)) {
105 if (cache_is_expired(detail, tmp)) {
106 hlist_del_init_rcu(&tmp->cache_list);
107 detail->entries --;
108 if (cache_is_valid(tmp) == -EAGAIN)
109 set_bit(CACHE_NEGATIVE, &tmp->flags);
110 cache_fresh_locked(tmp, 0, detail);
111 freeme = tmp;
112 break;
113 }
114 cache_get(tmp);
115 spin_unlock(&detail->hash_lock);
116 cache_put(new, detail);
117 return tmp;
118 }
119 }
120
121 hlist_add_head_rcu(&new->cache_list, head);
122 detail->entries++;
123 cache_get(new);
124 spin_unlock(&detail->hash_lock);
125
126 if (freeme) {
127 cache_fresh_unlocked(freeme, detail);
128 cache_put(freeme, detail);
129 }
130 return new;
131}
132
133struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
134 struct cache_head *key, int hash)
135{
136 struct cache_head *ret;
137
138 ret = sunrpc_cache_find_rcu(detail, key, hash);
139 if (ret)
140 return ret;
141 /* Didn't find anything, insert an empty entry */
142 return sunrpc_cache_add_entry(detail, key, hash);
143}
144EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
145
146static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
147
148static void cache_fresh_locked(struct cache_head *head, time_t expiry,
149 struct cache_detail *detail)
150{
151 time_t now = seconds_since_boot();
152 if (now <= detail->flush_time)
153 /* ensure it isn't immediately treated as expired */
154 now = detail->flush_time + 1;
155 head->expiry_time = expiry;
156 head->last_refresh = now;
157 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
158 set_bit(CACHE_VALID, &head->flags);
159}
160
161static void cache_fresh_unlocked(struct cache_head *head,
162 struct cache_detail *detail)
163{
164 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
165 cache_revisit_request(head);
166 cache_dequeue(detail, head);
167 }
168}
169
170struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
171 struct cache_head *new, struct cache_head *old, int hash)
172{
173 /* The 'old' entry is to be replaced by 'new'.
174 * If 'old' is not VALID, we update it directly,
175 * otherwise we need to replace it
176 */
177 struct cache_head *tmp;
178
179 if (!test_bit(CACHE_VALID, &old->flags)) {
180 spin_lock(&detail->hash_lock);
181 if (!test_bit(CACHE_VALID, &old->flags)) {
182 if (test_bit(CACHE_NEGATIVE, &new->flags))
183 set_bit(CACHE_NEGATIVE, &old->flags);
184 else
185 detail->update(old, new);
186 cache_fresh_locked(old, new->expiry_time, detail);
187 spin_unlock(&detail->hash_lock);
188 cache_fresh_unlocked(old, detail);
189 return old;
190 }
191 spin_unlock(&detail->hash_lock);
192 }
193 /* We need to insert a new entry */
194 tmp = detail->alloc();
195 if (!tmp) {
196 cache_put(old, detail);
197 return NULL;
198 }
199 cache_init(tmp, detail);
200 detail->init(tmp, old);
201
202 spin_lock(&detail->hash_lock);
203 if (test_bit(CACHE_NEGATIVE, &new->flags))
204 set_bit(CACHE_NEGATIVE, &tmp->flags);
205 else
206 detail->update(tmp, new);
207 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
208 detail->entries++;
209 cache_get(tmp);
210 cache_fresh_locked(tmp, new->expiry_time, detail);
211 cache_fresh_locked(old, 0, detail);
212 spin_unlock(&detail->hash_lock);
213 cache_fresh_unlocked(tmp, detail);
214 cache_fresh_unlocked(old, detail);
215 cache_put(old, detail);
216 return tmp;
217}
218EXPORT_SYMBOL_GPL(sunrpc_cache_update);
219
220static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
221{
222 if (cd->cache_upcall)
223 return cd->cache_upcall(cd, h);
224 return sunrpc_cache_pipe_upcall(cd, h);
225}
226
227static inline int cache_is_valid(struct cache_head *h)
228{
229 if (!test_bit(CACHE_VALID, &h->flags))
230 return -EAGAIN;
231 else {
232 /* entry is valid */
233 if (test_bit(CACHE_NEGATIVE, &h->flags))
234 return -ENOENT;
235 else {
236 /*
237 * In combination with write barrier in
238 * sunrpc_cache_update, ensures that anyone
239 * using the cache entry after this sees the
240 * updated contents:
241 */
242 smp_rmb();
243 return 0;
244 }
245 }
246}
247
248static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
249{
250 int rv;
251
252 spin_lock(&detail->hash_lock);
253 rv = cache_is_valid(h);
254 if (rv == -EAGAIN) {
255 set_bit(CACHE_NEGATIVE, &h->flags);
256 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
257 detail);
258 rv = -ENOENT;
259 }
260 spin_unlock(&detail->hash_lock);
261 cache_fresh_unlocked(h, detail);
262 return rv;
263}
264
265/*
266 * This is the generic cache management routine for all
267 * the authentication caches.
268 * It checks the currency of a cache item and will (later)
269 * initiate an upcall to fill it if needed.
270 *
271 *
272 * Returns 0 if the cache_head can be used, or cache_puts it and returns
273 * -EAGAIN if upcall is pending and request has been queued
274 * -ETIMEDOUT if upcall failed or request could not be queue or
275 * upcall completed but item is still invalid (implying that
276 * the cache item has been replaced with a newer one).
277 * -ENOENT if cache entry was negative
278 */
279int cache_check(struct cache_detail *detail,
280 struct cache_head *h, struct cache_req *rqstp)
281{
282 int rv;
283 long refresh_age, age;
284
285 /* First decide return status as best we can */
286 rv = cache_is_valid(h);
287
288 /* now see if we want to start an upcall */
289 refresh_age = (h->expiry_time - h->last_refresh);
290 age = seconds_since_boot() - h->last_refresh;
291
292 if (rqstp == NULL) {
293 if (rv == -EAGAIN)
294 rv = -ENOENT;
295 } else if (rv == -EAGAIN ||
296 (h->expiry_time != 0 && age > refresh_age/2)) {
297 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
298 refresh_age, age);
299 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
300 switch (cache_make_upcall(detail, h)) {
301 case -EINVAL:
302 rv = try_to_negate_entry(detail, h);
303 break;
304 case -EAGAIN:
305 cache_fresh_unlocked(h, detail);
306 break;
307 }
308 } else if (!cache_listeners_exist(detail))
309 rv = try_to_negate_entry(detail, h);
310 }
311
312 if (rv == -EAGAIN) {
313 if (!cache_defer_req(rqstp, h)) {
314 /*
315 * Request was not deferred; handle it as best
316 * we can ourselves:
317 */
318 rv = cache_is_valid(h);
319 if (rv == -EAGAIN)
320 rv = -ETIMEDOUT;
321 }
322 }
323 if (rv)
324 cache_put(h, detail);
325 return rv;
326}
327EXPORT_SYMBOL_GPL(cache_check);
328
329/*
330 * caches need to be periodically cleaned.
331 * For this we maintain a list of cache_detail and
332 * a current pointer into that list and into the table
333 * for that entry.
334 *
335 * Each time cache_clean is called it finds the next non-empty entry
336 * in the current table and walks the list in that entry
337 * looking for entries that can be removed.
338 *
339 * An entry gets removed if:
340 * - The expiry is before current time
341 * - The last_refresh time is before the flush_time for that cache
342 *
343 * later we might drop old entries with non-NEVER expiry if that table
344 * is getting 'full' for some definition of 'full'
345 *
346 * The question of "how often to scan a table" is an interesting one
347 * and is answered in part by the use of the "nextcheck" field in the
348 * cache_detail.
349 * When a scan of a table begins, the nextcheck field is set to a time
350 * that is well into the future.
351 * While scanning, if an expiry time is found that is earlier than the
352 * current nextcheck time, nextcheck is set to that expiry time.
353 * If the flush_time is ever set to a time earlier than the nextcheck
354 * time, the nextcheck time is then set to that flush_time.
355 *
356 * A table is then only scanned if the current time is at least
357 * the nextcheck time.
358 *
359 */
360
361static LIST_HEAD(cache_list);
362static DEFINE_SPINLOCK(cache_list_lock);
363static struct cache_detail *current_detail;
364static int current_index;
365
366static void do_cache_clean(struct work_struct *work);
367static struct delayed_work cache_cleaner;
368
369void sunrpc_init_cache_detail(struct cache_detail *cd)
370{
371 spin_lock_init(&cd->hash_lock);
372 INIT_LIST_HEAD(&cd->queue);
373 spin_lock(&cache_list_lock);
374 cd->nextcheck = 0;
375 cd->entries = 0;
376 atomic_set(&cd->writers, 0);
377 cd->last_close = 0;
378 cd->last_warn = -1;
379 list_add(&cd->others, &cache_list);
380 spin_unlock(&cache_list_lock);
381
382 /* start the cleaning process */
383 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
384}
385EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
386
387void sunrpc_destroy_cache_detail(struct cache_detail *cd)
388{
389 cache_purge(cd);
390 spin_lock(&cache_list_lock);
391 spin_lock(&cd->hash_lock);
392 if (current_detail == cd)
393 current_detail = NULL;
394 list_del_init(&cd->others);
395 spin_unlock(&cd->hash_lock);
396 spin_unlock(&cache_list_lock);
397 if (list_empty(&cache_list)) {
398 /* module must be being unloaded so its safe to kill the worker */
399 cancel_delayed_work_sync(&cache_cleaner);
400 }
401}
402EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
403
404/* clean cache tries to find something to clean
405 * and cleans it.
406 * It returns 1 if it cleaned something,
407 * 0 if it didn't find anything this time
408 * -1 if it fell off the end of the list.
409 */
410static int cache_clean(void)
411{
412 int rv = 0;
413 struct list_head *next;
414
415 spin_lock(&cache_list_lock);
416
417 /* find a suitable table if we don't already have one */
418 while (current_detail == NULL ||
419 current_index >= current_detail->hash_size) {
420 if (current_detail)
421 next = current_detail->others.next;
422 else
423 next = cache_list.next;
424 if (next == &cache_list) {
425 current_detail = NULL;
426 spin_unlock(&cache_list_lock);
427 return -1;
428 }
429 current_detail = list_entry(next, struct cache_detail, others);
430 if (current_detail->nextcheck > seconds_since_boot())
431 current_index = current_detail->hash_size;
432 else {
433 current_index = 0;
434 current_detail->nextcheck = seconds_since_boot()+30*60;
435 }
436 }
437
438 /* find a non-empty bucket in the table */
439 while (current_detail &&
440 current_index < current_detail->hash_size &&
441 hlist_empty(¤t_detail->hash_table[current_index]))
442 current_index++;
443
444 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
445
446 if (current_detail && current_index < current_detail->hash_size) {
447 struct cache_head *ch = NULL;
448 struct cache_detail *d;
449 struct hlist_head *head;
450 struct hlist_node *tmp;
451
452 spin_lock(¤t_detail->hash_lock);
453
454 /* Ok, now to clean this strand */
455
456 head = ¤t_detail->hash_table[current_index];
457 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
458 if (current_detail->nextcheck > ch->expiry_time)
459 current_detail->nextcheck = ch->expiry_time+1;
460 if (!cache_is_expired(current_detail, ch))
461 continue;
462
463 hlist_del_init_rcu(&ch->cache_list);
464 current_detail->entries--;
465 rv = 1;
466 break;
467 }
468
469 spin_unlock(¤t_detail->hash_lock);
470 d = current_detail;
471 if (!ch)
472 current_index ++;
473 spin_unlock(&cache_list_lock);
474 if (ch) {
475 set_bit(CACHE_CLEANED, &ch->flags);
476 cache_fresh_unlocked(ch, d);
477 cache_put(ch, d);
478 }
479 } else
480 spin_unlock(&cache_list_lock);
481
482 return rv;
483}
484
485/*
486 * We want to regularly clean the cache, so we need to schedule some work ...
487 */
488static void do_cache_clean(struct work_struct *work)
489{
490 int delay = 5;
491 if (cache_clean() == -1)
492 delay = round_jiffies_relative(30*HZ);
493
494 if (list_empty(&cache_list))
495 delay = 0;
496
497 if (delay)
498 queue_delayed_work(system_power_efficient_wq,
499 &cache_cleaner, delay);
500}
501
502
503/*
504 * Clean all caches promptly. This just calls cache_clean
505 * repeatedly until we are sure that every cache has had a chance to
506 * be fully cleaned
507 */
508void cache_flush(void)
509{
510 while (cache_clean() != -1)
511 cond_resched();
512 while (cache_clean() != -1)
513 cond_resched();
514}
515EXPORT_SYMBOL_GPL(cache_flush);
516
517void cache_purge(struct cache_detail *detail)
518{
519 struct cache_head *ch = NULL;
520 struct hlist_head *head = NULL;
521 struct hlist_node *tmp = NULL;
522 int i = 0;
523
524 spin_lock(&detail->hash_lock);
525 if (!detail->entries) {
526 spin_unlock(&detail->hash_lock);
527 return;
528 }
529
530 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
531 for (i = 0; i < detail->hash_size; i++) {
532 head = &detail->hash_table[i];
533 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
534 hlist_del_init_rcu(&ch->cache_list);
535 detail->entries--;
536
537 set_bit(CACHE_CLEANED, &ch->flags);
538 spin_unlock(&detail->hash_lock);
539 cache_fresh_unlocked(ch, detail);
540 cache_put(ch, detail);
541 spin_lock(&detail->hash_lock);
542 }
543 }
544 spin_unlock(&detail->hash_lock);
545}
546EXPORT_SYMBOL_GPL(cache_purge);
547
548
549/*
550 * Deferral and Revisiting of Requests.
551 *
552 * If a cache lookup finds a pending entry, we
553 * need to defer the request and revisit it later.
554 * All deferred requests are stored in a hash table,
555 * indexed by "struct cache_head *".
556 * As it may be wasteful to store a whole request
557 * structure, we allow the request to provide a
558 * deferred form, which must contain a
559 * 'struct cache_deferred_req'
560 * This cache_deferred_req contains a method to allow
561 * it to be revisited when cache info is available
562 */
563
564#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
565#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
566
567#define DFR_MAX 300 /* ??? */
568
569static DEFINE_SPINLOCK(cache_defer_lock);
570static LIST_HEAD(cache_defer_list);
571static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
572static int cache_defer_cnt;
573
574static void __unhash_deferred_req(struct cache_deferred_req *dreq)
575{
576 hlist_del_init(&dreq->hash);
577 if (!list_empty(&dreq->recent)) {
578 list_del_init(&dreq->recent);
579 cache_defer_cnt--;
580 }
581}
582
583static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
584{
585 int hash = DFR_HASH(item);
586
587 INIT_LIST_HEAD(&dreq->recent);
588 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
589}
590
591static void setup_deferral(struct cache_deferred_req *dreq,
592 struct cache_head *item,
593 int count_me)
594{
595
596 dreq->item = item;
597
598 spin_lock(&cache_defer_lock);
599
600 __hash_deferred_req(dreq, item);
601
602 if (count_me) {
603 cache_defer_cnt++;
604 list_add(&dreq->recent, &cache_defer_list);
605 }
606
607 spin_unlock(&cache_defer_lock);
608
609}
610
611struct thread_deferred_req {
612 struct cache_deferred_req handle;
613 struct completion completion;
614};
615
616static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
617{
618 struct thread_deferred_req *dr =
619 container_of(dreq, struct thread_deferred_req, handle);
620 complete(&dr->completion);
621}
622
623static void cache_wait_req(struct cache_req *req, struct cache_head *item)
624{
625 struct thread_deferred_req sleeper;
626 struct cache_deferred_req *dreq = &sleeper.handle;
627
628 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
629 dreq->revisit = cache_restart_thread;
630
631 setup_deferral(dreq, item, 0);
632
633 if (!test_bit(CACHE_PENDING, &item->flags) ||
634 wait_for_completion_interruptible_timeout(
635 &sleeper.completion, req->thread_wait) <= 0) {
636 /* The completion wasn't completed, so we need
637 * to clean up
638 */
639 spin_lock(&cache_defer_lock);
640 if (!hlist_unhashed(&sleeper.handle.hash)) {
641 __unhash_deferred_req(&sleeper.handle);
642 spin_unlock(&cache_defer_lock);
643 } else {
644 /* cache_revisit_request already removed
645 * this from the hash table, but hasn't
646 * called ->revisit yet. It will very soon
647 * and we need to wait for it.
648 */
649 spin_unlock(&cache_defer_lock);
650 wait_for_completion(&sleeper.completion);
651 }
652 }
653}
654
655static void cache_limit_defers(void)
656{
657 /* Make sure we haven't exceed the limit of allowed deferred
658 * requests.
659 */
660 struct cache_deferred_req *discard = NULL;
661
662 if (cache_defer_cnt <= DFR_MAX)
663 return;
664
665 spin_lock(&cache_defer_lock);
666
667 /* Consider removing either the first or the last */
668 if (cache_defer_cnt > DFR_MAX) {
669 if (prandom_u32() & 1)
670 discard = list_entry(cache_defer_list.next,
671 struct cache_deferred_req, recent);
672 else
673 discard = list_entry(cache_defer_list.prev,
674 struct cache_deferred_req, recent);
675 __unhash_deferred_req(discard);
676 }
677 spin_unlock(&cache_defer_lock);
678 if (discard)
679 discard->revisit(discard, 1);
680}
681
682/* Return true if and only if a deferred request is queued. */
683static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
684{
685 struct cache_deferred_req *dreq;
686
687 if (req->thread_wait) {
688 cache_wait_req(req, item);
689 if (!test_bit(CACHE_PENDING, &item->flags))
690 return false;
691 }
692 dreq = req->defer(req);
693 if (dreq == NULL)
694 return false;
695 setup_deferral(dreq, item, 1);
696 if (!test_bit(CACHE_PENDING, &item->flags))
697 /* Bit could have been cleared before we managed to
698 * set up the deferral, so need to revisit just in case
699 */
700 cache_revisit_request(item);
701
702 cache_limit_defers();
703 return true;
704}
705
706static void cache_revisit_request(struct cache_head *item)
707{
708 struct cache_deferred_req *dreq;
709 struct list_head pending;
710 struct hlist_node *tmp;
711 int hash = DFR_HASH(item);
712
713 INIT_LIST_HEAD(&pending);
714 spin_lock(&cache_defer_lock);
715
716 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
717 if (dreq->item == item) {
718 __unhash_deferred_req(dreq);
719 list_add(&dreq->recent, &pending);
720 }
721
722 spin_unlock(&cache_defer_lock);
723
724 while (!list_empty(&pending)) {
725 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
726 list_del_init(&dreq->recent);
727 dreq->revisit(dreq, 0);
728 }
729}
730
731void cache_clean_deferred(void *owner)
732{
733 struct cache_deferred_req *dreq, *tmp;
734 struct list_head pending;
735
736
737 INIT_LIST_HEAD(&pending);
738 spin_lock(&cache_defer_lock);
739
740 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
741 if (dreq->owner == owner) {
742 __unhash_deferred_req(dreq);
743 list_add(&dreq->recent, &pending);
744 }
745 }
746 spin_unlock(&cache_defer_lock);
747
748 while (!list_empty(&pending)) {
749 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
750 list_del_init(&dreq->recent);
751 dreq->revisit(dreq, 1);
752 }
753}
754
755/*
756 * communicate with user-space
757 *
758 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
759 * On read, you get a full request, or block.
760 * On write, an update request is processed.
761 * Poll works if anything to read, and always allows write.
762 *
763 * Implemented by linked list of requests. Each open file has
764 * a ->private that also exists in this list. New requests are added
765 * to the end and may wakeup and preceding readers.
766 * New readers are added to the head. If, on read, an item is found with
767 * CACHE_UPCALLING clear, we free it from the list.
768 *
769 */
770
771static DEFINE_SPINLOCK(queue_lock);
772static DEFINE_MUTEX(queue_io_mutex);
773
774struct cache_queue {
775 struct list_head list;
776 int reader; /* if 0, then request */
777};
778struct cache_request {
779 struct cache_queue q;
780 struct cache_head *item;
781 char * buf;
782 int len;
783 int readers;
784};
785struct cache_reader {
786 struct cache_queue q;
787 int offset; /* if non-0, we have a refcnt on next request */
788};
789
790static int cache_request(struct cache_detail *detail,
791 struct cache_request *crq)
792{
793 char *bp = crq->buf;
794 int len = PAGE_SIZE;
795
796 detail->cache_request(detail, crq->item, &bp, &len);
797 if (len < 0)
798 return -EAGAIN;
799 return PAGE_SIZE - len;
800}
801
802static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
803 loff_t *ppos, struct cache_detail *cd)
804{
805 struct cache_reader *rp = filp->private_data;
806 struct cache_request *rq;
807 struct inode *inode = file_inode(filp);
808 int err;
809
810 if (count == 0)
811 return 0;
812
813 inode_lock(inode); /* protect against multiple concurrent
814 * readers on this file */
815 again:
816 spin_lock(&queue_lock);
817 /* need to find next request */
818 while (rp->q.list.next != &cd->queue &&
819 list_entry(rp->q.list.next, struct cache_queue, list)
820 ->reader) {
821 struct list_head *next = rp->q.list.next;
822 list_move(&rp->q.list, next);
823 }
824 if (rp->q.list.next == &cd->queue) {
825 spin_unlock(&queue_lock);
826 inode_unlock(inode);
827 WARN_ON_ONCE(rp->offset);
828 return 0;
829 }
830 rq = container_of(rp->q.list.next, struct cache_request, q.list);
831 WARN_ON_ONCE(rq->q.reader);
832 if (rp->offset == 0)
833 rq->readers++;
834 spin_unlock(&queue_lock);
835
836 if (rq->len == 0) {
837 err = cache_request(cd, rq);
838 if (err < 0)
839 goto out;
840 rq->len = err;
841 }
842
843 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
844 err = -EAGAIN;
845 spin_lock(&queue_lock);
846 list_move(&rp->q.list, &rq->q.list);
847 spin_unlock(&queue_lock);
848 } else {
849 if (rp->offset + count > rq->len)
850 count = rq->len - rp->offset;
851 err = -EFAULT;
852 if (copy_to_user(buf, rq->buf + rp->offset, count))
853 goto out;
854 rp->offset += count;
855 if (rp->offset >= rq->len) {
856 rp->offset = 0;
857 spin_lock(&queue_lock);
858 list_move(&rp->q.list, &rq->q.list);
859 spin_unlock(&queue_lock);
860 }
861 err = 0;
862 }
863 out:
864 if (rp->offset == 0) {
865 /* need to release rq */
866 spin_lock(&queue_lock);
867 rq->readers--;
868 if (rq->readers == 0 &&
869 !test_bit(CACHE_PENDING, &rq->item->flags)) {
870 list_del(&rq->q.list);
871 spin_unlock(&queue_lock);
872 cache_put(rq->item, cd);
873 kfree(rq->buf);
874 kfree(rq);
875 } else
876 spin_unlock(&queue_lock);
877 }
878 if (err == -EAGAIN)
879 goto again;
880 inode_unlock(inode);
881 return err ? err : count;
882}
883
884static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
885 size_t count, struct cache_detail *cd)
886{
887 ssize_t ret;
888
889 if (count == 0)
890 return -EINVAL;
891 if (copy_from_user(kaddr, buf, count))
892 return -EFAULT;
893 kaddr[count] = '\0';
894 ret = cd->cache_parse(cd, kaddr, count);
895 if (!ret)
896 ret = count;
897 return ret;
898}
899
900static ssize_t cache_slow_downcall(const char __user *buf,
901 size_t count, struct cache_detail *cd)
902{
903 static char write_buf[8192]; /* protected by queue_io_mutex */
904 ssize_t ret = -EINVAL;
905
906 if (count >= sizeof(write_buf))
907 goto out;
908 mutex_lock(&queue_io_mutex);
909 ret = cache_do_downcall(write_buf, buf, count, cd);
910 mutex_unlock(&queue_io_mutex);
911out:
912 return ret;
913}
914
915static ssize_t cache_downcall(struct address_space *mapping,
916 const char __user *buf,
917 size_t count, struct cache_detail *cd)
918{
919 struct page *page;
920 char *kaddr;
921 ssize_t ret = -ENOMEM;
922
923 if (count >= PAGE_SIZE)
924 goto out_slow;
925
926 page = find_or_create_page(mapping, 0, GFP_KERNEL);
927 if (!page)
928 goto out_slow;
929
930 kaddr = kmap(page);
931 ret = cache_do_downcall(kaddr, buf, count, cd);
932 kunmap(page);
933 unlock_page(page);
934 put_page(page);
935 return ret;
936out_slow:
937 return cache_slow_downcall(buf, count, cd);
938}
939
940static ssize_t cache_write(struct file *filp, const char __user *buf,
941 size_t count, loff_t *ppos,
942 struct cache_detail *cd)
943{
944 struct address_space *mapping = filp->f_mapping;
945 struct inode *inode = file_inode(filp);
946 ssize_t ret = -EINVAL;
947
948 if (!cd->cache_parse)
949 goto out;
950
951 inode_lock(inode);
952 ret = cache_downcall(mapping, buf, count, cd);
953 inode_unlock(inode);
954out:
955 return ret;
956}
957
958static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
959
960static __poll_t cache_poll(struct file *filp, poll_table *wait,
961 struct cache_detail *cd)
962{
963 __poll_t mask;
964 struct cache_reader *rp = filp->private_data;
965 struct cache_queue *cq;
966
967 poll_wait(filp, &queue_wait, wait);
968
969 /* alway allow write */
970 mask = EPOLLOUT | EPOLLWRNORM;
971
972 if (!rp)
973 return mask;
974
975 spin_lock(&queue_lock);
976
977 for (cq= &rp->q; &cq->list != &cd->queue;
978 cq = list_entry(cq->list.next, struct cache_queue, list))
979 if (!cq->reader) {
980 mask |= EPOLLIN | EPOLLRDNORM;
981 break;
982 }
983 spin_unlock(&queue_lock);
984 return mask;
985}
986
987static int cache_ioctl(struct inode *ino, struct file *filp,
988 unsigned int cmd, unsigned long arg,
989 struct cache_detail *cd)
990{
991 int len = 0;
992 struct cache_reader *rp = filp->private_data;
993 struct cache_queue *cq;
994
995 if (cmd != FIONREAD || !rp)
996 return -EINVAL;
997
998 spin_lock(&queue_lock);
999
1000 /* only find the length remaining in current request,
1001 * or the length of the next request
1002 */
1003 for (cq= &rp->q; &cq->list != &cd->queue;
1004 cq = list_entry(cq->list.next, struct cache_queue, list))
1005 if (!cq->reader) {
1006 struct cache_request *cr =
1007 container_of(cq, struct cache_request, q);
1008 len = cr->len - rp->offset;
1009 break;
1010 }
1011 spin_unlock(&queue_lock);
1012
1013 return put_user(len, (int __user *)arg);
1014}
1015
1016static int cache_open(struct inode *inode, struct file *filp,
1017 struct cache_detail *cd)
1018{
1019 struct cache_reader *rp = NULL;
1020
1021 if (!cd || !try_module_get(cd->owner))
1022 return -EACCES;
1023 nonseekable_open(inode, filp);
1024 if (filp->f_mode & FMODE_READ) {
1025 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1026 if (!rp) {
1027 module_put(cd->owner);
1028 return -ENOMEM;
1029 }
1030 rp->offset = 0;
1031 rp->q.reader = 1;
1032
1033 spin_lock(&queue_lock);
1034 list_add(&rp->q.list, &cd->queue);
1035 spin_unlock(&queue_lock);
1036 }
1037 if (filp->f_mode & FMODE_WRITE)
1038 atomic_inc(&cd->writers);
1039 filp->private_data = rp;
1040 return 0;
1041}
1042
1043static int cache_release(struct inode *inode, struct file *filp,
1044 struct cache_detail *cd)
1045{
1046 struct cache_reader *rp = filp->private_data;
1047
1048 if (rp) {
1049 spin_lock(&queue_lock);
1050 if (rp->offset) {
1051 struct cache_queue *cq;
1052 for (cq= &rp->q; &cq->list != &cd->queue;
1053 cq = list_entry(cq->list.next, struct cache_queue, list))
1054 if (!cq->reader) {
1055 container_of(cq, struct cache_request, q)
1056 ->readers--;
1057 break;
1058 }
1059 rp->offset = 0;
1060 }
1061 list_del(&rp->q.list);
1062 spin_unlock(&queue_lock);
1063
1064 filp->private_data = NULL;
1065 kfree(rp);
1066
1067 }
1068 if (filp->f_mode & FMODE_WRITE) {
1069 atomic_dec(&cd->writers);
1070 cd->last_close = seconds_since_boot();
1071 }
1072 module_put(cd->owner);
1073 return 0;
1074}
1075
1076
1077
1078static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1079{
1080 struct cache_queue *cq, *tmp;
1081 struct cache_request *cr;
1082 struct list_head dequeued;
1083
1084 INIT_LIST_HEAD(&dequeued);
1085 spin_lock(&queue_lock);
1086 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1087 if (!cq->reader) {
1088 cr = container_of(cq, struct cache_request, q);
1089 if (cr->item != ch)
1090 continue;
1091 if (test_bit(CACHE_PENDING, &ch->flags))
1092 /* Lost a race and it is pending again */
1093 break;
1094 if (cr->readers != 0)
1095 continue;
1096 list_move(&cr->q.list, &dequeued);
1097 }
1098 spin_unlock(&queue_lock);
1099 while (!list_empty(&dequeued)) {
1100 cr = list_entry(dequeued.next, struct cache_request, q.list);
1101 list_del(&cr->q.list);
1102 cache_put(cr->item, detail);
1103 kfree(cr->buf);
1104 kfree(cr);
1105 }
1106}
1107
1108/*
1109 * Support routines for text-based upcalls.
1110 * Fields are separated by spaces.
1111 * Fields are either mangled to quote space tab newline slosh with slosh
1112 * or a hexified with a leading \x
1113 * Record is terminated with newline.
1114 *
1115 */
1116
1117void qword_add(char **bpp, int *lp, char *str)
1118{
1119 char *bp = *bpp;
1120 int len = *lp;
1121 int ret;
1122
1123 if (len < 0) return;
1124
1125 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1126 if (ret >= len) {
1127 bp += len;
1128 len = -1;
1129 } else {
1130 bp += ret;
1131 len -= ret;
1132 *bp++ = ' ';
1133 len--;
1134 }
1135 *bpp = bp;
1136 *lp = len;
1137}
1138EXPORT_SYMBOL_GPL(qword_add);
1139
1140void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1141{
1142 char *bp = *bpp;
1143 int len = *lp;
1144
1145 if (len < 0) return;
1146
1147 if (len > 2) {
1148 *bp++ = '\\';
1149 *bp++ = 'x';
1150 len -= 2;
1151 while (blen && len >= 2) {
1152 bp = hex_byte_pack(bp, *buf++);
1153 len -= 2;
1154 blen--;
1155 }
1156 }
1157 if (blen || len<1) len = -1;
1158 else {
1159 *bp++ = ' ';
1160 len--;
1161 }
1162 *bpp = bp;
1163 *lp = len;
1164}
1165EXPORT_SYMBOL_GPL(qword_addhex);
1166
1167static void warn_no_listener(struct cache_detail *detail)
1168{
1169 if (detail->last_warn != detail->last_close) {
1170 detail->last_warn = detail->last_close;
1171 if (detail->warn_no_listener)
1172 detail->warn_no_listener(detail, detail->last_close != 0);
1173 }
1174}
1175
1176static bool cache_listeners_exist(struct cache_detail *detail)
1177{
1178 if (atomic_read(&detail->writers))
1179 return true;
1180 if (detail->last_close == 0)
1181 /* This cache was never opened */
1182 return false;
1183 if (detail->last_close < seconds_since_boot() - 30)
1184 /*
1185 * We allow for the possibility that someone might
1186 * restart a userspace daemon without restarting the
1187 * server; but after 30 seconds, we give up.
1188 */
1189 return false;
1190 return true;
1191}
1192
1193/*
1194 * register an upcall request to user-space and queue it up for read() by the
1195 * upcall daemon.
1196 *
1197 * Each request is at most one page long.
1198 */
1199int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1200{
1201
1202 char *buf;
1203 struct cache_request *crq;
1204 int ret = 0;
1205
1206 if (!detail->cache_request)
1207 return -EINVAL;
1208
1209 if (!cache_listeners_exist(detail)) {
1210 warn_no_listener(detail);
1211 return -EINVAL;
1212 }
1213 if (test_bit(CACHE_CLEANED, &h->flags))
1214 /* Too late to make an upcall */
1215 return -EAGAIN;
1216
1217 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1218 if (!buf)
1219 return -EAGAIN;
1220
1221 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1222 if (!crq) {
1223 kfree(buf);
1224 return -EAGAIN;
1225 }
1226
1227 crq->q.reader = 0;
1228 crq->buf = buf;
1229 crq->len = 0;
1230 crq->readers = 0;
1231 spin_lock(&queue_lock);
1232 if (test_bit(CACHE_PENDING, &h->flags)) {
1233 crq->item = cache_get(h);
1234 list_add_tail(&crq->q.list, &detail->queue);
1235 } else
1236 /* Lost a race, no longer PENDING, so don't enqueue */
1237 ret = -EAGAIN;
1238 spin_unlock(&queue_lock);
1239 wake_up(&queue_wait);
1240 if (ret == -EAGAIN) {
1241 kfree(buf);
1242 kfree(crq);
1243 }
1244 return ret;
1245}
1246EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1247
1248/*
1249 * parse a message from user-space and pass it
1250 * to an appropriate cache
1251 * Messages are, like requests, separated into fields by
1252 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1253 *
1254 * Message is
1255 * reply cachename expiry key ... content....
1256 *
1257 * key and content are both parsed by cache
1258 */
1259
1260int qword_get(char **bpp, char *dest, int bufsize)
1261{
1262 /* return bytes copied, or -1 on error */
1263 char *bp = *bpp;
1264 int len = 0;
1265
1266 while (*bp == ' ') bp++;
1267
1268 if (bp[0] == '\\' && bp[1] == 'x') {
1269 /* HEX STRING */
1270 bp += 2;
1271 while (len < bufsize - 1) {
1272 int h, l;
1273
1274 h = hex_to_bin(bp[0]);
1275 if (h < 0)
1276 break;
1277
1278 l = hex_to_bin(bp[1]);
1279 if (l < 0)
1280 break;
1281
1282 *dest++ = (h << 4) | l;
1283 bp += 2;
1284 len++;
1285 }
1286 } else {
1287 /* text with \nnn octal quoting */
1288 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1289 if (*bp == '\\' &&
1290 isodigit(bp[1]) && (bp[1] <= '3') &&
1291 isodigit(bp[2]) &&
1292 isodigit(bp[3])) {
1293 int byte = (*++bp -'0');
1294 bp++;
1295 byte = (byte << 3) | (*bp++ - '0');
1296 byte = (byte << 3) | (*bp++ - '0');
1297 *dest++ = byte;
1298 len++;
1299 } else {
1300 *dest++ = *bp++;
1301 len++;
1302 }
1303 }
1304 }
1305
1306 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1307 return -1;
1308 while (*bp == ' ') bp++;
1309 *bpp = bp;
1310 *dest = '\0';
1311 return len;
1312}
1313EXPORT_SYMBOL_GPL(qword_get);
1314
1315
1316/*
1317 * support /proc/net/rpc/$CACHENAME/content
1318 * as a seqfile.
1319 * We call ->cache_show passing NULL for the item to
1320 * get a header, then pass each real item in the cache
1321 */
1322
1323static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1324{
1325 loff_t n = *pos;
1326 unsigned int hash, entry;
1327 struct cache_head *ch;
1328 struct cache_detail *cd = m->private;
1329
1330 if (!n--)
1331 return SEQ_START_TOKEN;
1332 hash = n >> 32;
1333 entry = n & ((1LL<<32) - 1);
1334
1335 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1336 if (!entry--)
1337 return ch;
1338 n &= ~((1LL<<32) - 1);
1339 do {
1340 hash++;
1341 n += 1LL<<32;
1342 } while(hash < cd->hash_size &&
1343 hlist_empty(&cd->hash_table[hash]));
1344 if (hash >= cd->hash_size)
1345 return NULL;
1346 *pos = n+1;
1347 return hlist_entry_safe(rcu_dereference_raw(
1348 hlist_first_rcu(&cd->hash_table[hash])),
1349 struct cache_head, cache_list);
1350}
1351
1352static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1353{
1354 struct cache_head *ch = p;
1355 int hash = (*pos >> 32);
1356 struct cache_detail *cd = m->private;
1357
1358 if (p == SEQ_START_TOKEN)
1359 hash = 0;
1360 else if (ch->cache_list.next == NULL) {
1361 hash++;
1362 *pos += 1LL<<32;
1363 } else {
1364 ++*pos;
1365 return hlist_entry_safe(rcu_dereference_raw(
1366 hlist_next_rcu(&ch->cache_list)),
1367 struct cache_head, cache_list);
1368 }
1369 *pos &= ~((1LL<<32) - 1);
1370 while (hash < cd->hash_size &&
1371 hlist_empty(&cd->hash_table[hash])) {
1372 hash++;
1373 *pos += 1LL<<32;
1374 }
1375 if (hash >= cd->hash_size)
1376 return NULL;
1377 ++*pos;
1378 return hlist_entry_safe(rcu_dereference_raw(
1379 hlist_first_rcu(&cd->hash_table[hash])),
1380 struct cache_head, cache_list);
1381}
1382
1383void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1384 __acquires(RCU)
1385{
1386 rcu_read_lock();
1387 return __cache_seq_start(m, pos);
1388}
1389EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1390
1391void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1392{
1393 return cache_seq_next(file, p, pos);
1394}
1395EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1396
1397void cache_seq_stop_rcu(struct seq_file *m, void *p)
1398 __releases(RCU)
1399{
1400 rcu_read_unlock();
1401}
1402EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1403
1404static int c_show(struct seq_file *m, void *p)
1405{
1406 struct cache_head *cp = p;
1407 struct cache_detail *cd = m->private;
1408
1409 if (p == SEQ_START_TOKEN)
1410 return cd->cache_show(m, cd, NULL);
1411
1412 ifdebug(CACHE)
1413 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1414 convert_to_wallclock(cp->expiry_time),
1415 kref_read(&cp->ref), cp->flags);
1416 cache_get(cp);
1417 if (cache_check(cd, cp, NULL))
1418 /* cache_check does a cache_put on failure */
1419 seq_printf(m, "# ");
1420 else {
1421 if (cache_is_expired(cd, cp))
1422 seq_printf(m, "# ");
1423 cache_put(cp, cd);
1424 }
1425
1426 return cd->cache_show(m, cd, cp);
1427}
1428
1429static const struct seq_operations cache_content_op = {
1430 .start = cache_seq_start_rcu,
1431 .next = cache_seq_next_rcu,
1432 .stop = cache_seq_stop_rcu,
1433 .show = c_show,
1434};
1435
1436static int content_open(struct inode *inode, struct file *file,
1437 struct cache_detail *cd)
1438{
1439 struct seq_file *seq;
1440 int err;
1441
1442 if (!cd || !try_module_get(cd->owner))
1443 return -EACCES;
1444
1445 err = seq_open(file, &cache_content_op);
1446 if (err) {
1447 module_put(cd->owner);
1448 return err;
1449 }
1450
1451 seq = file->private_data;
1452 seq->private = cd;
1453 return 0;
1454}
1455
1456static int content_release(struct inode *inode, struct file *file,
1457 struct cache_detail *cd)
1458{
1459 int ret = seq_release(inode, file);
1460 module_put(cd->owner);
1461 return ret;
1462}
1463
1464static int open_flush(struct inode *inode, struct file *file,
1465 struct cache_detail *cd)
1466{
1467 if (!cd || !try_module_get(cd->owner))
1468 return -EACCES;
1469 return nonseekable_open(inode, file);
1470}
1471
1472static int release_flush(struct inode *inode, struct file *file,
1473 struct cache_detail *cd)
1474{
1475 module_put(cd->owner);
1476 return 0;
1477}
1478
1479static ssize_t read_flush(struct file *file, char __user *buf,
1480 size_t count, loff_t *ppos,
1481 struct cache_detail *cd)
1482{
1483 char tbuf[22];
1484 size_t len;
1485
1486 len = snprintf(tbuf, sizeof(tbuf), "%lu\n",
1487 convert_to_wallclock(cd->flush_time));
1488 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1489}
1490
1491static ssize_t write_flush(struct file *file, const char __user *buf,
1492 size_t count, loff_t *ppos,
1493 struct cache_detail *cd)
1494{
1495 char tbuf[20];
1496 char *ep;
1497 time_t now;
1498
1499 if (*ppos || count > sizeof(tbuf)-1)
1500 return -EINVAL;
1501 if (copy_from_user(tbuf, buf, count))
1502 return -EFAULT;
1503 tbuf[count] = 0;
1504 simple_strtoul(tbuf, &ep, 0);
1505 if (*ep && *ep != '\n')
1506 return -EINVAL;
1507 /* Note that while we check that 'buf' holds a valid number,
1508 * we always ignore the value and just flush everything.
1509 * Making use of the number leads to races.
1510 */
1511
1512 now = seconds_since_boot();
1513 /* Always flush everything, so behave like cache_purge()
1514 * Do this by advancing flush_time to the current time,
1515 * or by one second if it has already reached the current time.
1516 * Newly added cache entries will always have ->last_refresh greater
1517 * that ->flush_time, so they don't get flushed prematurely.
1518 */
1519
1520 if (cd->flush_time >= now)
1521 now = cd->flush_time + 1;
1522
1523 cd->flush_time = now;
1524 cd->nextcheck = now;
1525 cache_flush();
1526
1527 if (cd->flush)
1528 cd->flush();
1529
1530 *ppos += count;
1531 return count;
1532}
1533
1534static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1535 size_t count, loff_t *ppos)
1536{
1537 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1538
1539 return cache_read(filp, buf, count, ppos, cd);
1540}
1541
1542static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1543 size_t count, loff_t *ppos)
1544{
1545 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1546
1547 return cache_write(filp, buf, count, ppos, cd);
1548}
1549
1550static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1551{
1552 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1553
1554 return cache_poll(filp, wait, cd);
1555}
1556
1557static long cache_ioctl_procfs(struct file *filp,
1558 unsigned int cmd, unsigned long arg)
1559{
1560 struct inode *inode = file_inode(filp);
1561 struct cache_detail *cd = PDE_DATA(inode);
1562
1563 return cache_ioctl(inode, filp, cmd, arg, cd);
1564}
1565
1566static int cache_open_procfs(struct inode *inode, struct file *filp)
1567{
1568 struct cache_detail *cd = PDE_DATA(inode);
1569
1570 return cache_open(inode, filp, cd);
1571}
1572
1573static int cache_release_procfs(struct inode *inode, struct file *filp)
1574{
1575 struct cache_detail *cd = PDE_DATA(inode);
1576
1577 return cache_release(inode, filp, cd);
1578}
1579
1580static const struct file_operations cache_file_operations_procfs = {
1581 .owner = THIS_MODULE,
1582 .llseek = no_llseek,
1583 .read = cache_read_procfs,
1584 .write = cache_write_procfs,
1585 .poll = cache_poll_procfs,
1586 .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1587 .open = cache_open_procfs,
1588 .release = cache_release_procfs,
1589};
1590
1591static int content_open_procfs(struct inode *inode, struct file *filp)
1592{
1593 struct cache_detail *cd = PDE_DATA(inode);
1594
1595 return content_open(inode, filp, cd);
1596}
1597
1598static int content_release_procfs(struct inode *inode, struct file *filp)
1599{
1600 struct cache_detail *cd = PDE_DATA(inode);
1601
1602 return content_release(inode, filp, cd);
1603}
1604
1605static const struct file_operations content_file_operations_procfs = {
1606 .open = content_open_procfs,
1607 .read = seq_read,
1608 .llseek = seq_lseek,
1609 .release = content_release_procfs,
1610};
1611
1612static int open_flush_procfs(struct inode *inode, struct file *filp)
1613{
1614 struct cache_detail *cd = PDE_DATA(inode);
1615
1616 return open_flush(inode, filp, cd);
1617}
1618
1619static int release_flush_procfs(struct inode *inode, struct file *filp)
1620{
1621 struct cache_detail *cd = PDE_DATA(inode);
1622
1623 return release_flush(inode, filp, cd);
1624}
1625
1626static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1627 size_t count, loff_t *ppos)
1628{
1629 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1630
1631 return read_flush(filp, buf, count, ppos, cd);
1632}
1633
1634static ssize_t write_flush_procfs(struct file *filp,
1635 const char __user *buf,
1636 size_t count, loff_t *ppos)
1637{
1638 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1639
1640 return write_flush(filp, buf, count, ppos, cd);
1641}
1642
1643static const struct file_operations cache_flush_operations_procfs = {
1644 .open = open_flush_procfs,
1645 .read = read_flush_procfs,
1646 .write = write_flush_procfs,
1647 .release = release_flush_procfs,
1648 .llseek = no_llseek,
1649};
1650
1651static void remove_cache_proc_entries(struct cache_detail *cd)
1652{
1653 if (cd->procfs) {
1654 proc_remove(cd->procfs);
1655 cd->procfs = NULL;
1656 }
1657}
1658
1659#ifdef CONFIG_PROC_FS
1660static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1661{
1662 struct proc_dir_entry *p;
1663 struct sunrpc_net *sn;
1664
1665 sn = net_generic(net, sunrpc_net_id);
1666 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1667 if (cd->procfs == NULL)
1668 goto out_nomem;
1669
1670 p = proc_create_data("flush", S_IFREG | 0600,
1671 cd->procfs, &cache_flush_operations_procfs, cd);
1672 if (p == NULL)
1673 goto out_nomem;
1674
1675 if (cd->cache_request || cd->cache_parse) {
1676 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1677 &cache_file_operations_procfs, cd);
1678 if (p == NULL)
1679 goto out_nomem;
1680 }
1681 if (cd->cache_show) {
1682 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1683 &content_file_operations_procfs, cd);
1684 if (p == NULL)
1685 goto out_nomem;
1686 }
1687 return 0;
1688out_nomem:
1689 remove_cache_proc_entries(cd);
1690 return -ENOMEM;
1691}
1692#else /* CONFIG_PROC_FS */
1693static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1694{
1695 return 0;
1696}
1697#endif
1698
1699void __init cache_initialize(void)
1700{
1701 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1702}
1703
1704int cache_register_net(struct cache_detail *cd, struct net *net)
1705{
1706 int ret;
1707
1708 sunrpc_init_cache_detail(cd);
1709 ret = create_cache_proc_entries(cd, net);
1710 if (ret)
1711 sunrpc_destroy_cache_detail(cd);
1712 return ret;
1713}
1714EXPORT_SYMBOL_GPL(cache_register_net);
1715
1716void cache_unregister_net(struct cache_detail *cd, struct net *net)
1717{
1718 remove_cache_proc_entries(cd);
1719 sunrpc_destroy_cache_detail(cd);
1720}
1721EXPORT_SYMBOL_GPL(cache_unregister_net);
1722
1723struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1724{
1725 struct cache_detail *cd;
1726 int i;
1727
1728 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1729 if (cd == NULL)
1730 return ERR_PTR(-ENOMEM);
1731
1732 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1733 GFP_KERNEL);
1734 if (cd->hash_table == NULL) {
1735 kfree(cd);
1736 return ERR_PTR(-ENOMEM);
1737 }
1738
1739 for (i = 0; i < cd->hash_size; i++)
1740 INIT_HLIST_HEAD(&cd->hash_table[i]);
1741 cd->net = net;
1742 return cd;
1743}
1744EXPORT_SYMBOL_GPL(cache_create_net);
1745
1746void cache_destroy_net(struct cache_detail *cd, struct net *net)
1747{
1748 kfree(cd->hash_table);
1749 kfree(cd);
1750}
1751EXPORT_SYMBOL_GPL(cache_destroy_net);
1752
1753static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1754 size_t count, loff_t *ppos)
1755{
1756 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1757
1758 return cache_read(filp, buf, count, ppos, cd);
1759}
1760
1761static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1762 size_t count, loff_t *ppos)
1763{
1764 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1765
1766 return cache_write(filp, buf, count, ppos, cd);
1767}
1768
1769static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1770{
1771 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1772
1773 return cache_poll(filp, wait, cd);
1774}
1775
1776static long cache_ioctl_pipefs(struct file *filp,
1777 unsigned int cmd, unsigned long arg)
1778{
1779 struct inode *inode = file_inode(filp);
1780 struct cache_detail *cd = RPC_I(inode)->private;
1781
1782 return cache_ioctl(inode, filp, cmd, arg, cd);
1783}
1784
1785static int cache_open_pipefs(struct inode *inode, struct file *filp)
1786{
1787 struct cache_detail *cd = RPC_I(inode)->private;
1788
1789 return cache_open(inode, filp, cd);
1790}
1791
1792static int cache_release_pipefs(struct inode *inode, struct file *filp)
1793{
1794 struct cache_detail *cd = RPC_I(inode)->private;
1795
1796 return cache_release(inode, filp, cd);
1797}
1798
1799const struct file_operations cache_file_operations_pipefs = {
1800 .owner = THIS_MODULE,
1801 .llseek = no_llseek,
1802 .read = cache_read_pipefs,
1803 .write = cache_write_pipefs,
1804 .poll = cache_poll_pipefs,
1805 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1806 .open = cache_open_pipefs,
1807 .release = cache_release_pipefs,
1808};
1809
1810static int content_open_pipefs(struct inode *inode, struct file *filp)
1811{
1812 struct cache_detail *cd = RPC_I(inode)->private;
1813
1814 return content_open(inode, filp, cd);
1815}
1816
1817static int content_release_pipefs(struct inode *inode, struct file *filp)
1818{
1819 struct cache_detail *cd = RPC_I(inode)->private;
1820
1821 return content_release(inode, filp, cd);
1822}
1823
1824const struct file_operations content_file_operations_pipefs = {
1825 .open = content_open_pipefs,
1826 .read = seq_read,
1827 .llseek = seq_lseek,
1828 .release = content_release_pipefs,
1829};
1830
1831static int open_flush_pipefs(struct inode *inode, struct file *filp)
1832{
1833 struct cache_detail *cd = RPC_I(inode)->private;
1834
1835 return open_flush(inode, filp, cd);
1836}
1837
1838static int release_flush_pipefs(struct inode *inode, struct file *filp)
1839{
1840 struct cache_detail *cd = RPC_I(inode)->private;
1841
1842 return release_flush(inode, filp, cd);
1843}
1844
1845static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1846 size_t count, loff_t *ppos)
1847{
1848 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1849
1850 return read_flush(filp, buf, count, ppos, cd);
1851}
1852
1853static ssize_t write_flush_pipefs(struct file *filp,
1854 const char __user *buf,
1855 size_t count, loff_t *ppos)
1856{
1857 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1858
1859 return write_flush(filp, buf, count, ppos, cd);
1860}
1861
1862const struct file_operations cache_flush_operations_pipefs = {
1863 .open = open_flush_pipefs,
1864 .read = read_flush_pipefs,
1865 .write = write_flush_pipefs,
1866 .release = release_flush_pipefs,
1867 .llseek = no_llseek,
1868};
1869
1870int sunrpc_cache_register_pipefs(struct dentry *parent,
1871 const char *name, umode_t umode,
1872 struct cache_detail *cd)
1873{
1874 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1875 if (IS_ERR(dir))
1876 return PTR_ERR(dir);
1877 cd->pipefs = dir;
1878 return 0;
1879}
1880EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1881
1882void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1883{
1884 if (cd->pipefs) {
1885 rpc_remove_cache_dir(cd->pipefs);
1886 cd->pipefs = NULL;
1887 }
1888}
1889EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1890
1891void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1892{
1893 spin_lock(&cd->hash_lock);
1894 if (!hlist_unhashed(&h->cache_list)){
1895 hlist_del_init_rcu(&h->cache_list);
1896 cd->entries--;
1897 spin_unlock(&cd->hash_lock);
1898 cache_put(h, cd);
1899 } else
1900 spin_unlock(&cd->hash_lock);
1901}
1902EXPORT_SYMBOL_GPL(sunrpc_cache_unhash);
1/*
2 * net/sunrpc/cache.c
3 *
4 * Generic code for various authentication-related caches
5 * used by sunrpc clients and servers.
6 *
7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
8 *
9 * Released under terms in GPL version 2. See COPYING.
10 *
11 */
12
13#include <linux/types.h>
14#include <linux/fs.h>
15#include <linux/file.h>
16#include <linux/slab.h>
17#include <linux/signal.h>
18#include <linux/sched.h>
19#include <linux/kmod.h>
20#include <linux/list.h>
21#include <linux/module.h>
22#include <linux/ctype.h>
23#include <asm/uaccess.h>
24#include <linux/poll.h>
25#include <linux/seq_file.h>
26#include <linux/proc_fs.h>
27#include <linux/net.h>
28#include <linux/workqueue.h>
29#include <linux/mutex.h>
30#include <linux/pagemap.h>
31#include <asm/ioctls.h>
32#include <linux/sunrpc/types.h>
33#include <linux/sunrpc/cache.h>
34#include <linux/sunrpc/stats.h>
35#include <linux/sunrpc/rpc_pipe_fs.h>
36#include "netns.h"
37
38#define RPCDBG_FACILITY RPCDBG_CACHE
39
40static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
41static void cache_revisit_request(struct cache_head *item);
42
43static void cache_init(struct cache_head *h)
44{
45 time_t now = seconds_since_boot();
46 h->next = NULL;
47 h->flags = 0;
48 kref_init(&h->ref);
49 h->expiry_time = now + CACHE_NEW_EXPIRY;
50 h->last_refresh = now;
51}
52
53static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
54{
55 return (h->expiry_time < seconds_since_boot()) ||
56 (detail->flush_time > h->last_refresh);
57}
58
59struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
60 struct cache_head *key, int hash)
61{
62 struct cache_head **head, **hp;
63 struct cache_head *new = NULL, *freeme = NULL;
64
65 head = &detail->hash_table[hash];
66
67 read_lock(&detail->hash_lock);
68
69 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
70 struct cache_head *tmp = *hp;
71 if (detail->match(tmp, key)) {
72 if (cache_is_expired(detail, tmp))
73 /* This entry is expired, we will discard it. */
74 break;
75 cache_get(tmp);
76 read_unlock(&detail->hash_lock);
77 return tmp;
78 }
79 }
80 read_unlock(&detail->hash_lock);
81 /* Didn't find anything, insert an empty entry */
82
83 new = detail->alloc();
84 if (!new)
85 return NULL;
86 /* must fully initialise 'new', else
87 * we might get lose if we need to
88 * cache_put it soon.
89 */
90 cache_init(new);
91 detail->init(new, key);
92
93 write_lock(&detail->hash_lock);
94
95 /* check if entry appeared while we slept */
96 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
97 struct cache_head *tmp = *hp;
98 if (detail->match(tmp, key)) {
99 if (cache_is_expired(detail, tmp)) {
100 *hp = tmp->next;
101 tmp->next = NULL;
102 detail->entries --;
103 freeme = tmp;
104 break;
105 }
106 cache_get(tmp);
107 write_unlock(&detail->hash_lock);
108 cache_put(new, detail);
109 return tmp;
110 }
111 }
112 new->next = *head;
113 *head = new;
114 detail->entries++;
115 cache_get(new);
116 write_unlock(&detail->hash_lock);
117
118 if (freeme)
119 cache_put(freeme, detail);
120 return new;
121}
122EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
123
124
125static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
126
127static void cache_fresh_locked(struct cache_head *head, time_t expiry)
128{
129 head->expiry_time = expiry;
130 head->last_refresh = seconds_since_boot();
131 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
132 set_bit(CACHE_VALID, &head->flags);
133}
134
135static void cache_fresh_unlocked(struct cache_head *head,
136 struct cache_detail *detail)
137{
138 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
139 cache_revisit_request(head);
140 cache_dequeue(detail, head);
141 }
142}
143
144struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
145 struct cache_head *new, struct cache_head *old, int hash)
146{
147 /* The 'old' entry is to be replaced by 'new'.
148 * If 'old' is not VALID, we update it directly,
149 * otherwise we need to replace it
150 */
151 struct cache_head **head;
152 struct cache_head *tmp;
153
154 if (!test_bit(CACHE_VALID, &old->flags)) {
155 write_lock(&detail->hash_lock);
156 if (!test_bit(CACHE_VALID, &old->flags)) {
157 if (test_bit(CACHE_NEGATIVE, &new->flags))
158 set_bit(CACHE_NEGATIVE, &old->flags);
159 else
160 detail->update(old, new);
161 cache_fresh_locked(old, new->expiry_time);
162 write_unlock(&detail->hash_lock);
163 cache_fresh_unlocked(old, detail);
164 return old;
165 }
166 write_unlock(&detail->hash_lock);
167 }
168 /* We need to insert a new entry */
169 tmp = detail->alloc();
170 if (!tmp) {
171 cache_put(old, detail);
172 return NULL;
173 }
174 cache_init(tmp);
175 detail->init(tmp, old);
176 head = &detail->hash_table[hash];
177
178 write_lock(&detail->hash_lock);
179 if (test_bit(CACHE_NEGATIVE, &new->flags))
180 set_bit(CACHE_NEGATIVE, &tmp->flags);
181 else
182 detail->update(tmp, new);
183 tmp->next = *head;
184 *head = tmp;
185 detail->entries++;
186 cache_get(tmp);
187 cache_fresh_locked(tmp, new->expiry_time);
188 cache_fresh_locked(old, 0);
189 write_unlock(&detail->hash_lock);
190 cache_fresh_unlocked(tmp, detail);
191 cache_fresh_unlocked(old, detail);
192 cache_put(old, detail);
193 return tmp;
194}
195EXPORT_SYMBOL_GPL(sunrpc_cache_update);
196
197static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
198{
199 if (!cd->cache_upcall)
200 return -EINVAL;
201 return cd->cache_upcall(cd, h);
202}
203
204static inline int cache_is_valid(struct cache_detail *detail, struct cache_head *h)
205{
206 if (!test_bit(CACHE_VALID, &h->flags))
207 return -EAGAIN;
208 else {
209 /* entry is valid */
210 if (test_bit(CACHE_NEGATIVE, &h->flags))
211 return -ENOENT;
212 else {
213 /*
214 * In combination with write barrier in
215 * sunrpc_cache_update, ensures that anyone
216 * using the cache entry after this sees the
217 * updated contents:
218 */
219 smp_rmb();
220 return 0;
221 }
222 }
223}
224
225static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
226{
227 int rv;
228
229 write_lock(&detail->hash_lock);
230 rv = cache_is_valid(detail, h);
231 if (rv != -EAGAIN) {
232 write_unlock(&detail->hash_lock);
233 return rv;
234 }
235 set_bit(CACHE_NEGATIVE, &h->flags);
236 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
237 write_unlock(&detail->hash_lock);
238 cache_fresh_unlocked(h, detail);
239 return -ENOENT;
240}
241
242/*
243 * This is the generic cache management routine for all
244 * the authentication caches.
245 * It checks the currency of a cache item and will (later)
246 * initiate an upcall to fill it if needed.
247 *
248 *
249 * Returns 0 if the cache_head can be used, or cache_puts it and returns
250 * -EAGAIN if upcall is pending and request has been queued
251 * -ETIMEDOUT if upcall failed or request could not be queue or
252 * upcall completed but item is still invalid (implying that
253 * the cache item has been replaced with a newer one).
254 * -ENOENT if cache entry was negative
255 */
256int cache_check(struct cache_detail *detail,
257 struct cache_head *h, struct cache_req *rqstp)
258{
259 int rv;
260 long refresh_age, age;
261
262 /* First decide return status as best we can */
263 rv = cache_is_valid(detail, h);
264
265 /* now see if we want to start an upcall */
266 refresh_age = (h->expiry_time - h->last_refresh);
267 age = seconds_since_boot() - h->last_refresh;
268
269 if (rqstp == NULL) {
270 if (rv == -EAGAIN)
271 rv = -ENOENT;
272 } else if (rv == -EAGAIN || age > refresh_age/2) {
273 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
274 refresh_age, age);
275 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
276 switch (cache_make_upcall(detail, h)) {
277 case -EINVAL:
278 clear_bit(CACHE_PENDING, &h->flags);
279 cache_revisit_request(h);
280 rv = try_to_negate_entry(detail, h);
281 break;
282 case -EAGAIN:
283 clear_bit(CACHE_PENDING, &h->flags);
284 cache_revisit_request(h);
285 break;
286 }
287 }
288 }
289
290 if (rv == -EAGAIN) {
291 if (!cache_defer_req(rqstp, h)) {
292 /*
293 * Request was not deferred; handle it as best
294 * we can ourselves:
295 */
296 rv = cache_is_valid(detail, h);
297 if (rv == -EAGAIN)
298 rv = -ETIMEDOUT;
299 }
300 }
301 if (rv)
302 cache_put(h, detail);
303 return rv;
304}
305EXPORT_SYMBOL_GPL(cache_check);
306
307/*
308 * caches need to be periodically cleaned.
309 * For this we maintain a list of cache_detail and
310 * a current pointer into that list and into the table
311 * for that entry.
312 *
313 * Each time clean_cache is called it finds the next non-empty entry
314 * in the current table and walks the list in that entry
315 * looking for entries that can be removed.
316 *
317 * An entry gets removed if:
318 * - The expiry is before current time
319 * - The last_refresh time is before the flush_time for that cache
320 *
321 * later we might drop old entries with non-NEVER expiry if that table
322 * is getting 'full' for some definition of 'full'
323 *
324 * The question of "how often to scan a table" is an interesting one
325 * and is answered in part by the use of the "nextcheck" field in the
326 * cache_detail.
327 * When a scan of a table begins, the nextcheck field is set to a time
328 * that is well into the future.
329 * While scanning, if an expiry time is found that is earlier than the
330 * current nextcheck time, nextcheck is set to that expiry time.
331 * If the flush_time is ever set to a time earlier than the nextcheck
332 * time, the nextcheck time is then set to that flush_time.
333 *
334 * A table is then only scanned if the current time is at least
335 * the nextcheck time.
336 *
337 */
338
339static LIST_HEAD(cache_list);
340static DEFINE_SPINLOCK(cache_list_lock);
341static struct cache_detail *current_detail;
342static int current_index;
343
344static void do_cache_clean(struct work_struct *work);
345static struct delayed_work cache_cleaner;
346
347static void sunrpc_init_cache_detail(struct cache_detail *cd)
348{
349 rwlock_init(&cd->hash_lock);
350 INIT_LIST_HEAD(&cd->queue);
351 spin_lock(&cache_list_lock);
352 cd->nextcheck = 0;
353 cd->entries = 0;
354 atomic_set(&cd->readers, 0);
355 cd->last_close = 0;
356 cd->last_warn = -1;
357 list_add(&cd->others, &cache_list);
358 spin_unlock(&cache_list_lock);
359
360 /* start the cleaning process */
361 schedule_delayed_work(&cache_cleaner, 0);
362}
363
364static void sunrpc_destroy_cache_detail(struct cache_detail *cd)
365{
366 cache_purge(cd);
367 spin_lock(&cache_list_lock);
368 write_lock(&cd->hash_lock);
369 if (cd->entries || atomic_read(&cd->inuse)) {
370 write_unlock(&cd->hash_lock);
371 spin_unlock(&cache_list_lock);
372 goto out;
373 }
374 if (current_detail == cd)
375 current_detail = NULL;
376 list_del_init(&cd->others);
377 write_unlock(&cd->hash_lock);
378 spin_unlock(&cache_list_lock);
379 if (list_empty(&cache_list)) {
380 /* module must be being unloaded so its safe to kill the worker */
381 cancel_delayed_work_sync(&cache_cleaner);
382 }
383 return;
384out:
385 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
386}
387
388/* clean cache tries to find something to clean
389 * and cleans it.
390 * It returns 1 if it cleaned something,
391 * 0 if it didn't find anything this time
392 * -1 if it fell off the end of the list.
393 */
394static int cache_clean(void)
395{
396 int rv = 0;
397 struct list_head *next;
398
399 spin_lock(&cache_list_lock);
400
401 /* find a suitable table if we don't already have one */
402 while (current_detail == NULL ||
403 current_index >= current_detail->hash_size) {
404 if (current_detail)
405 next = current_detail->others.next;
406 else
407 next = cache_list.next;
408 if (next == &cache_list) {
409 current_detail = NULL;
410 spin_unlock(&cache_list_lock);
411 return -1;
412 }
413 current_detail = list_entry(next, struct cache_detail, others);
414 if (current_detail->nextcheck > seconds_since_boot())
415 current_index = current_detail->hash_size;
416 else {
417 current_index = 0;
418 current_detail->nextcheck = seconds_since_boot()+30*60;
419 }
420 }
421
422 /* find a non-empty bucket in the table */
423 while (current_detail &&
424 current_index < current_detail->hash_size &&
425 current_detail->hash_table[current_index] == NULL)
426 current_index++;
427
428 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
429
430 if (current_detail && current_index < current_detail->hash_size) {
431 struct cache_head *ch, **cp;
432 struct cache_detail *d;
433
434 write_lock(¤t_detail->hash_lock);
435
436 /* Ok, now to clean this strand */
437
438 cp = & current_detail->hash_table[current_index];
439 for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
440 if (current_detail->nextcheck > ch->expiry_time)
441 current_detail->nextcheck = ch->expiry_time+1;
442 if (!cache_is_expired(current_detail, ch))
443 continue;
444
445 *cp = ch->next;
446 ch->next = NULL;
447 current_detail->entries--;
448 rv = 1;
449 break;
450 }
451
452 write_unlock(¤t_detail->hash_lock);
453 d = current_detail;
454 if (!ch)
455 current_index ++;
456 spin_unlock(&cache_list_lock);
457 if (ch) {
458 if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
459 cache_dequeue(current_detail, ch);
460 cache_revisit_request(ch);
461 cache_put(ch, d);
462 }
463 } else
464 spin_unlock(&cache_list_lock);
465
466 return rv;
467}
468
469/*
470 * We want to regularly clean the cache, so we need to schedule some work ...
471 */
472static void do_cache_clean(struct work_struct *work)
473{
474 int delay = 5;
475 if (cache_clean() == -1)
476 delay = round_jiffies_relative(30*HZ);
477
478 if (list_empty(&cache_list))
479 delay = 0;
480
481 if (delay)
482 schedule_delayed_work(&cache_cleaner, delay);
483}
484
485
486/*
487 * Clean all caches promptly. This just calls cache_clean
488 * repeatedly until we are sure that every cache has had a chance to
489 * be fully cleaned
490 */
491void cache_flush(void)
492{
493 while (cache_clean() != -1)
494 cond_resched();
495 while (cache_clean() != -1)
496 cond_resched();
497}
498EXPORT_SYMBOL_GPL(cache_flush);
499
500void cache_purge(struct cache_detail *detail)
501{
502 detail->flush_time = LONG_MAX;
503 detail->nextcheck = seconds_since_boot();
504 cache_flush();
505 detail->flush_time = 1;
506}
507EXPORT_SYMBOL_GPL(cache_purge);
508
509
510/*
511 * Deferral and Revisiting of Requests.
512 *
513 * If a cache lookup finds a pending entry, we
514 * need to defer the request and revisit it later.
515 * All deferred requests are stored in a hash table,
516 * indexed by "struct cache_head *".
517 * As it may be wasteful to store a whole request
518 * structure, we allow the request to provide a
519 * deferred form, which must contain a
520 * 'struct cache_deferred_req'
521 * This cache_deferred_req contains a method to allow
522 * it to be revisited when cache info is available
523 */
524
525#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
526#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
527
528#define DFR_MAX 300 /* ??? */
529
530static DEFINE_SPINLOCK(cache_defer_lock);
531static LIST_HEAD(cache_defer_list);
532static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
533static int cache_defer_cnt;
534
535static void __unhash_deferred_req(struct cache_deferred_req *dreq)
536{
537 hlist_del_init(&dreq->hash);
538 if (!list_empty(&dreq->recent)) {
539 list_del_init(&dreq->recent);
540 cache_defer_cnt--;
541 }
542}
543
544static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
545{
546 int hash = DFR_HASH(item);
547
548 INIT_LIST_HEAD(&dreq->recent);
549 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
550}
551
552static void setup_deferral(struct cache_deferred_req *dreq,
553 struct cache_head *item,
554 int count_me)
555{
556
557 dreq->item = item;
558
559 spin_lock(&cache_defer_lock);
560
561 __hash_deferred_req(dreq, item);
562
563 if (count_me) {
564 cache_defer_cnt++;
565 list_add(&dreq->recent, &cache_defer_list);
566 }
567
568 spin_unlock(&cache_defer_lock);
569
570}
571
572struct thread_deferred_req {
573 struct cache_deferred_req handle;
574 struct completion completion;
575};
576
577static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
578{
579 struct thread_deferred_req *dr =
580 container_of(dreq, struct thread_deferred_req, handle);
581 complete(&dr->completion);
582}
583
584static void cache_wait_req(struct cache_req *req, struct cache_head *item)
585{
586 struct thread_deferred_req sleeper;
587 struct cache_deferred_req *dreq = &sleeper.handle;
588
589 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
590 dreq->revisit = cache_restart_thread;
591
592 setup_deferral(dreq, item, 0);
593
594 if (!test_bit(CACHE_PENDING, &item->flags) ||
595 wait_for_completion_interruptible_timeout(
596 &sleeper.completion, req->thread_wait) <= 0) {
597 /* The completion wasn't completed, so we need
598 * to clean up
599 */
600 spin_lock(&cache_defer_lock);
601 if (!hlist_unhashed(&sleeper.handle.hash)) {
602 __unhash_deferred_req(&sleeper.handle);
603 spin_unlock(&cache_defer_lock);
604 } else {
605 /* cache_revisit_request already removed
606 * this from the hash table, but hasn't
607 * called ->revisit yet. It will very soon
608 * and we need to wait for it.
609 */
610 spin_unlock(&cache_defer_lock);
611 wait_for_completion(&sleeper.completion);
612 }
613 }
614}
615
616static void cache_limit_defers(void)
617{
618 /* Make sure we haven't exceed the limit of allowed deferred
619 * requests.
620 */
621 struct cache_deferred_req *discard = NULL;
622
623 if (cache_defer_cnt <= DFR_MAX)
624 return;
625
626 spin_lock(&cache_defer_lock);
627
628 /* Consider removing either the first or the last */
629 if (cache_defer_cnt > DFR_MAX) {
630 if (net_random() & 1)
631 discard = list_entry(cache_defer_list.next,
632 struct cache_deferred_req, recent);
633 else
634 discard = list_entry(cache_defer_list.prev,
635 struct cache_deferred_req, recent);
636 __unhash_deferred_req(discard);
637 }
638 spin_unlock(&cache_defer_lock);
639 if (discard)
640 discard->revisit(discard, 1);
641}
642
643/* Return true if and only if a deferred request is queued. */
644static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
645{
646 struct cache_deferred_req *dreq;
647
648 if (req->thread_wait) {
649 cache_wait_req(req, item);
650 if (!test_bit(CACHE_PENDING, &item->flags))
651 return false;
652 }
653 dreq = req->defer(req);
654 if (dreq == NULL)
655 return false;
656 setup_deferral(dreq, item, 1);
657 if (!test_bit(CACHE_PENDING, &item->flags))
658 /* Bit could have been cleared before we managed to
659 * set up the deferral, so need to revisit just in case
660 */
661 cache_revisit_request(item);
662
663 cache_limit_defers();
664 return true;
665}
666
667static void cache_revisit_request(struct cache_head *item)
668{
669 struct cache_deferred_req *dreq;
670 struct list_head pending;
671 struct hlist_node *lp, *tmp;
672 int hash = DFR_HASH(item);
673
674 INIT_LIST_HEAD(&pending);
675 spin_lock(&cache_defer_lock);
676
677 hlist_for_each_entry_safe(dreq, lp, tmp, &cache_defer_hash[hash], hash)
678 if (dreq->item == item) {
679 __unhash_deferred_req(dreq);
680 list_add(&dreq->recent, &pending);
681 }
682
683 spin_unlock(&cache_defer_lock);
684
685 while (!list_empty(&pending)) {
686 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
687 list_del_init(&dreq->recent);
688 dreq->revisit(dreq, 0);
689 }
690}
691
692void cache_clean_deferred(void *owner)
693{
694 struct cache_deferred_req *dreq, *tmp;
695 struct list_head pending;
696
697
698 INIT_LIST_HEAD(&pending);
699 spin_lock(&cache_defer_lock);
700
701 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
702 if (dreq->owner == owner) {
703 __unhash_deferred_req(dreq);
704 list_add(&dreq->recent, &pending);
705 }
706 }
707 spin_unlock(&cache_defer_lock);
708
709 while (!list_empty(&pending)) {
710 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
711 list_del_init(&dreq->recent);
712 dreq->revisit(dreq, 1);
713 }
714}
715
716/*
717 * communicate with user-space
718 *
719 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
720 * On read, you get a full request, or block.
721 * On write, an update request is processed.
722 * Poll works if anything to read, and always allows write.
723 *
724 * Implemented by linked list of requests. Each open file has
725 * a ->private that also exists in this list. New requests are added
726 * to the end and may wakeup and preceding readers.
727 * New readers are added to the head. If, on read, an item is found with
728 * CACHE_UPCALLING clear, we free it from the list.
729 *
730 */
731
732static DEFINE_SPINLOCK(queue_lock);
733static DEFINE_MUTEX(queue_io_mutex);
734
735struct cache_queue {
736 struct list_head list;
737 int reader; /* if 0, then request */
738};
739struct cache_request {
740 struct cache_queue q;
741 struct cache_head *item;
742 char * buf;
743 int len;
744 int readers;
745};
746struct cache_reader {
747 struct cache_queue q;
748 int offset; /* if non-0, we have a refcnt on next request */
749};
750
751static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
752 loff_t *ppos, struct cache_detail *cd)
753{
754 struct cache_reader *rp = filp->private_data;
755 struct cache_request *rq;
756 struct inode *inode = filp->f_path.dentry->d_inode;
757 int err;
758
759 if (count == 0)
760 return 0;
761
762 mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
763 * readers on this file */
764 again:
765 spin_lock(&queue_lock);
766 /* need to find next request */
767 while (rp->q.list.next != &cd->queue &&
768 list_entry(rp->q.list.next, struct cache_queue, list)
769 ->reader) {
770 struct list_head *next = rp->q.list.next;
771 list_move(&rp->q.list, next);
772 }
773 if (rp->q.list.next == &cd->queue) {
774 spin_unlock(&queue_lock);
775 mutex_unlock(&inode->i_mutex);
776 BUG_ON(rp->offset);
777 return 0;
778 }
779 rq = container_of(rp->q.list.next, struct cache_request, q.list);
780 BUG_ON(rq->q.reader);
781 if (rp->offset == 0)
782 rq->readers++;
783 spin_unlock(&queue_lock);
784
785 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
786 err = -EAGAIN;
787 spin_lock(&queue_lock);
788 list_move(&rp->q.list, &rq->q.list);
789 spin_unlock(&queue_lock);
790 } else {
791 if (rp->offset + count > rq->len)
792 count = rq->len - rp->offset;
793 err = -EFAULT;
794 if (copy_to_user(buf, rq->buf + rp->offset, count))
795 goto out;
796 rp->offset += count;
797 if (rp->offset >= rq->len) {
798 rp->offset = 0;
799 spin_lock(&queue_lock);
800 list_move(&rp->q.list, &rq->q.list);
801 spin_unlock(&queue_lock);
802 }
803 err = 0;
804 }
805 out:
806 if (rp->offset == 0) {
807 /* need to release rq */
808 spin_lock(&queue_lock);
809 rq->readers--;
810 if (rq->readers == 0 &&
811 !test_bit(CACHE_PENDING, &rq->item->flags)) {
812 list_del(&rq->q.list);
813 spin_unlock(&queue_lock);
814 cache_put(rq->item, cd);
815 kfree(rq->buf);
816 kfree(rq);
817 } else
818 spin_unlock(&queue_lock);
819 }
820 if (err == -EAGAIN)
821 goto again;
822 mutex_unlock(&inode->i_mutex);
823 return err ? err : count;
824}
825
826static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
827 size_t count, struct cache_detail *cd)
828{
829 ssize_t ret;
830
831 if (copy_from_user(kaddr, buf, count))
832 return -EFAULT;
833 kaddr[count] = '\0';
834 ret = cd->cache_parse(cd, kaddr, count);
835 if (!ret)
836 ret = count;
837 return ret;
838}
839
840static ssize_t cache_slow_downcall(const char __user *buf,
841 size_t count, struct cache_detail *cd)
842{
843 static char write_buf[8192]; /* protected by queue_io_mutex */
844 ssize_t ret = -EINVAL;
845
846 if (count >= sizeof(write_buf))
847 goto out;
848 mutex_lock(&queue_io_mutex);
849 ret = cache_do_downcall(write_buf, buf, count, cd);
850 mutex_unlock(&queue_io_mutex);
851out:
852 return ret;
853}
854
855static ssize_t cache_downcall(struct address_space *mapping,
856 const char __user *buf,
857 size_t count, struct cache_detail *cd)
858{
859 struct page *page;
860 char *kaddr;
861 ssize_t ret = -ENOMEM;
862
863 if (count >= PAGE_CACHE_SIZE)
864 goto out_slow;
865
866 page = find_or_create_page(mapping, 0, GFP_KERNEL);
867 if (!page)
868 goto out_slow;
869
870 kaddr = kmap(page);
871 ret = cache_do_downcall(kaddr, buf, count, cd);
872 kunmap(page);
873 unlock_page(page);
874 page_cache_release(page);
875 return ret;
876out_slow:
877 return cache_slow_downcall(buf, count, cd);
878}
879
880static ssize_t cache_write(struct file *filp, const char __user *buf,
881 size_t count, loff_t *ppos,
882 struct cache_detail *cd)
883{
884 struct address_space *mapping = filp->f_mapping;
885 struct inode *inode = filp->f_path.dentry->d_inode;
886 ssize_t ret = -EINVAL;
887
888 if (!cd->cache_parse)
889 goto out;
890
891 mutex_lock(&inode->i_mutex);
892 ret = cache_downcall(mapping, buf, count, cd);
893 mutex_unlock(&inode->i_mutex);
894out:
895 return ret;
896}
897
898static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
899
900static unsigned int cache_poll(struct file *filp, poll_table *wait,
901 struct cache_detail *cd)
902{
903 unsigned int mask;
904 struct cache_reader *rp = filp->private_data;
905 struct cache_queue *cq;
906
907 poll_wait(filp, &queue_wait, wait);
908
909 /* alway allow write */
910 mask = POLL_OUT | POLLWRNORM;
911
912 if (!rp)
913 return mask;
914
915 spin_lock(&queue_lock);
916
917 for (cq= &rp->q; &cq->list != &cd->queue;
918 cq = list_entry(cq->list.next, struct cache_queue, list))
919 if (!cq->reader) {
920 mask |= POLLIN | POLLRDNORM;
921 break;
922 }
923 spin_unlock(&queue_lock);
924 return mask;
925}
926
927static int cache_ioctl(struct inode *ino, struct file *filp,
928 unsigned int cmd, unsigned long arg,
929 struct cache_detail *cd)
930{
931 int len = 0;
932 struct cache_reader *rp = filp->private_data;
933 struct cache_queue *cq;
934
935 if (cmd != FIONREAD || !rp)
936 return -EINVAL;
937
938 spin_lock(&queue_lock);
939
940 /* only find the length remaining in current request,
941 * or the length of the next request
942 */
943 for (cq= &rp->q; &cq->list != &cd->queue;
944 cq = list_entry(cq->list.next, struct cache_queue, list))
945 if (!cq->reader) {
946 struct cache_request *cr =
947 container_of(cq, struct cache_request, q);
948 len = cr->len - rp->offset;
949 break;
950 }
951 spin_unlock(&queue_lock);
952
953 return put_user(len, (int __user *)arg);
954}
955
956static int cache_open(struct inode *inode, struct file *filp,
957 struct cache_detail *cd)
958{
959 struct cache_reader *rp = NULL;
960
961 if (!cd || !try_module_get(cd->owner))
962 return -EACCES;
963 nonseekable_open(inode, filp);
964 if (filp->f_mode & FMODE_READ) {
965 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
966 if (!rp)
967 return -ENOMEM;
968 rp->offset = 0;
969 rp->q.reader = 1;
970 atomic_inc(&cd->readers);
971 spin_lock(&queue_lock);
972 list_add(&rp->q.list, &cd->queue);
973 spin_unlock(&queue_lock);
974 }
975 filp->private_data = rp;
976 return 0;
977}
978
979static int cache_release(struct inode *inode, struct file *filp,
980 struct cache_detail *cd)
981{
982 struct cache_reader *rp = filp->private_data;
983
984 if (rp) {
985 spin_lock(&queue_lock);
986 if (rp->offset) {
987 struct cache_queue *cq;
988 for (cq= &rp->q; &cq->list != &cd->queue;
989 cq = list_entry(cq->list.next, struct cache_queue, list))
990 if (!cq->reader) {
991 container_of(cq, struct cache_request, q)
992 ->readers--;
993 break;
994 }
995 rp->offset = 0;
996 }
997 list_del(&rp->q.list);
998 spin_unlock(&queue_lock);
999
1000 filp->private_data = NULL;
1001 kfree(rp);
1002
1003 cd->last_close = seconds_since_boot();
1004 atomic_dec(&cd->readers);
1005 }
1006 module_put(cd->owner);
1007 return 0;
1008}
1009
1010
1011
1012static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1013{
1014 struct cache_queue *cq;
1015 spin_lock(&queue_lock);
1016 list_for_each_entry(cq, &detail->queue, list)
1017 if (!cq->reader) {
1018 struct cache_request *cr = container_of(cq, struct cache_request, q);
1019 if (cr->item != ch)
1020 continue;
1021 if (cr->readers != 0)
1022 continue;
1023 list_del(&cr->q.list);
1024 spin_unlock(&queue_lock);
1025 cache_put(cr->item, detail);
1026 kfree(cr->buf);
1027 kfree(cr);
1028 return;
1029 }
1030 spin_unlock(&queue_lock);
1031}
1032
1033/*
1034 * Support routines for text-based upcalls.
1035 * Fields are separated by spaces.
1036 * Fields are either mangled to quote space tab newline slosh with slosh
1037 * or a hexified with a leading \x
1038 * Record is terminated with newline.
1039 *
1040 */
1041
1042void qword_add(char **bpp, int *lp, char *str)
1043{
1044 char *bp = *bpp;
1045 int len = *lp;
1046 char c;
1047
1048 if (len < 0) return;
1049
1050 while ((c=*str++) && len)
1051 switch(c) {
1052 case ' ':
1053 case '\t':
1054 case '\n':
1055 case '\\':
1056 if (len >= 4) {
1057 *bp++ = '\\';
1058 *bp++ = '0' + ((c & 0300)>>6);
1059 *bp++ = '0' + ((c & 0070)>>3);
1060 *bp++ = '0' + ((c & 0007)>>0);
1061 }
1062 len -= 4;
1063 break;
1064 default:
1065 *bp++ = c;
1066 len--;
1067 }
1068 if (c || len <1) len = -1;
1069 else {
1070 *bp++ = ' ';
1071 len--;
1072 }
1073 *bpp = bp;
1074 *lp = len;
1075}
1076EXPORT_SYMBOL_GPL(qword_add);
1077
1078void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1079{
1080 char *bp = *bpp;
1081 int len = *lp;
1082
1083 if (len < 0) return;
1084
1085 if (len > 2) {
1086 *bp++ = '\\';
1087 *bp++ = 'x';
1088 len -= 2;
1089 while (blen && len >= 2) {
1090 unsigned char c = *buf++;
1091 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1092 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1093 len -= 2;
1094 blen--;
1095 }
1096 }
1097 if (blen || len<1) len = -1;
1098 else {
1099 *bp++ = ' ';
1100 len--;
1101 }
1102 *bpp = bp;
1103 *lp = len;
1104}
1105EXPORT_SYMBOL_GPL(qword_addhex);
1106
1107static void warn_no_listener(struct cache_detail *detail)
1108{
1109 if (detail->last_warn != detail->last_close) {
1110 detail->last_warn = detail->last_close;
1111 if (detail->warn_no_listener)
1112 detail->warn_no_listener(detail, detail->last_close != 0);
1113 }
1114}
1115
1116static bool cache_listeners_exist(struct cache_detail *detail)
1117{
1118 if (atomic_read(&detail->readers))
1119 return true;
1120 if (detail->last_close == 0)
1121 /* This cache was never opened */
1122 return false;
1123 if (detail->last_close < seconds_since_boot() - 30)
1124 /*
1125 * We allow for the possibility that someone might
1126 * restart a userspace daemon without restarting the
1127 * server; but after 30 seconds, we give up.
1128 */
1129 return false;
1130 return true;
1131}
1132
1133/*
1134 * register an upcall request to user-space and queue it up for read() by the
1135 * upcall daemon.
1136 *
1137 * Each request is at most one page long.
1138 */
1139int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
1140 void (*cache_request)(struct cache_detail *,
1141 struct cache_head *,
1142 char **,
1143 int *))
1144{
1145
1146 char *buf;
1147 struct cache_request *crq;
1148 char *bp;
1149 int len;
1150
1151 if (!cache_listeners_exist(detail)) {
1152 warn_no_listener(detail);
1153 return -EINVAL;
1154 }
1155
1156 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1157 if (!buf)
1158 return -EAGAIN;
1159
1160 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1161 if (!crq) {
1162 kfree(buf);
1163 return -EAGAIN;
1164 }
1165
1166 bp = buf; len = PAGE_SIZE;
1167
1168 cache_request(detail, h, &bp, &len);
1169
1170 if (len < 0) {
1171 kfree(buf);
1172 kfree(crq);
1173 return -EAGAIN;
1174 }
1175 crq->q.reader = 0;
1176 crq->item = cache_get(h);
1177 crq->buf = buf;
1178 crq->len = PAGE_SIZE - len;
1179 crq->readers = 0;
1180 spin_lock(&queue_lock);
1181 list_add_tail(&crq->q.list, &detail->queue);
1182 spin_unlock(&queue_lock);
1183 wake_up(&queue_wait);
1184 return 0;
1185}
1186EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1187
1188/*
1189 * parse a message from user-space and pass it
1190 * to an appropriate cache
1191 * Messages are, like requests, separated into fields by
1192 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1193 *
1194 * Message is
1195 * reply cachename expiry key ... content....
1196 *
1197 * key and content are both parsed by cache
1198 */
1199
1200#define isodigit(c) (isdigit(c) && c <= '7')
1201int qword_get(char **bpp, char *dest, int bufsize)
1202{
1203 /* return bytes copied, or -1 on error */
1204 char *bp = *bpp;
1205 int len = 0;
1206
1207 while (*bp == ' ') bp++;
1208
1209 if (bp[0] == '\\' && bp[1] == 'x') {
1210 /* HEX STRING */
1211 bp += 2;
1212 while (len < bufsize) {
1213 int h, l;
1214
1215 h = hex_to_bin(bp[0]);
1216 if (h < 0)
1217 break;
1218
1219 l = hex_to_bin(bp[1]);
1220 if (l < 0)
1221 break;
1222
1223 *dest++ = (h << 4) | l;
1224 bp += 2;
1225 len++;
1226 }
1227 } else {
1228 /* text with \nnn octal quoting */
1229 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1230 if (*bp == '\\' &&
1231 isodigit(bp[1]) && (bp[1] <= '3') &&
1232 isodigit(bp[2]) &&
1233 isodigit(bp[3])) {
1234 int byte = (*++bp -'0');
1235 bp++;
1236 byte = (byte << 3) | (*bp++ - '0');
1237 byte = (byte << 3) | (*bp++ - '0');
1238 *dest++ = byte;
1239 len++;
1240 } else {
1241 *dest++ = *bp++;
1242 len++;
1243 }
1244 }
1245 }
1246
1247 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1248 return -1;
1249 while (*bp == ' ') bp++;
1250 *bpp = bp;
1251 *dest = '\0';
1252 return len;
1253}
1254EXPORT_SYMBOL_GPL(qword_get);
1255
1256
1257/*
1258 * support /proc/sunrpc/cache/$CACHENAME/content
1259 * as a seqfile.
1260 * We call ->cache_show passing NULL for the item to
1261 * get a header, then pass each real item in the cache
1262 */
1263
1264struct handle {
1265 struct cache_detail *cd;
1266};
1267
1268static void *c_start(struct seq_file *m, loff_t *pos)
1269 __acquires(cd->hash_lock)
1270{
1271 loff_t n = *pos;
1272 unsigned hash, entry;
1273 struct cache_head *ch;
1274 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1275
1276
1277 read_lock(&cd->hash_lock);
1278 if (!n--)
1279 return SEQ_START_TOKEN;
1280 hash = n >> 32;
1281 entry = n & ((1LL<<32) - 1);
1282
1283 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1284 if (!entry--)
1285 return ch;
1286 n &= ~((1LL<<32) - 1);
1287 do {
1288 hash++;
1289 n += 1LL<<32;
1290 } while(hash < cd->hash_size &&
1291 cd->hash_table[hash]==NULL);
1292 if (hash >= cd->hash_size)
1293 return NULL;
1294 *pos = n+1;
1295 return cd->hash_table[hash];
1296}
1297
1298static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1299{
1300 struct cache_head *ch = p;
1301 int hash = (*pos >> 32);
1302 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1303
1304 if (p == SEQ_START_TOKEN)
1305 hash = 0;
1306 else if (ch->next == NULL) {
1307 hash++;
1308 *pos += 1LL<<32;
1309 } else {
1310 ++*pos;
1311 return ch->next;
1312 }
1313 *pos &= ~((1LL<<32) - 1);
1314 while (hash < cd->hash_size &&
1315 cd->hash_table[hash] == NULL) {
1316 hash++;
1317 *pos += 1LL<<32;
1318 }
1319 if (hash >= cd->hash_size)
1320 return NULL;
1321 ++*pos;
1322 return cd->hash_table[hash];
1323}
1324
1325static void c_stop(struct seq_file *m, void *p)
1326 __releases(cd->hash_lock)
1327{
1328 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1329 read_unlock(&cd->hash_lock);
1330}
1331
1332static int c_show(struct seq_file *m, void *p)
1333{
1334 struct cache_head *cp = p;
1335 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1336
1337 if (p == SEQ_START_TOKEN)
1338 return cd->cache_show(m, cd, NULL);
1339
1340 ifdebug(CACHE)
1341 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1342 convert_to_wallclock(cp->expiry_time),
1343 atomic_read(&cp->ref.refcount), cp->flags);
1344 cache_get(cp);
1345 if (cache_check(cd, cp, NULL))
1346 /* cache_check does a cache_put on failure */
1347 seq_printf(m, "# ");
1348 else
1349 cache_put(cp, cd);
1350
1351 return cd->cache_show(m, cd, cp);
1352}
1353
1354static const struct seq_operations cache_content_op = {
1355 .start = c_start,
1356 .next = c_next,
1357 .stop = c_stop,
1358 .show = c_show,
1359};
1360
1361static int content_open(struct inode *inode, struct file *file,
1362 struct cache_detail *cd)
1363{
1364 struct handle *han;
1365
1366 if (!cd || !try_module_get(cd->owner))
1367 return -EACCES;
1368 han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1369 if (han == NULL) {
1370 module_put(cd->owner);
1371 return -ENOMEM;
1372 }
1373
1374 han->cd = cd;
1375 return 0;
1376}
1377
1378static int content_release(struct inode *inode, struct file *file,
1379 struct cache_detail *cd)
1380{
1381 int ret = seq_release_private(inode, file);
1382 module_put(cd->owner);
1383 return ret;
1384}
1385
1386static int open_flush(struct inode *inode, struct file *file,
1387 struct cache_detail *cd)
1388{
1389 if (!cd || !try_module_get(cd->owner))
1390 return -EACCES;
1391 return nonseekable_open(inode, file);
1392}
1393
1394static int release_flush(struct inode *inode, struct file *file,
1395 struct cache_detail *cd)
1396{
1397 module_put(cd->owner);
1398 return 0;
1399}
1400
1401static ssize_t read_flush(struct file *file, char __user *buf,
1402 size_t count, loff_t *ppos,
1403 struct cache_detail *cd)
1404{
1405 char tbuf[20];
1406 unsigned long p = *ppos;
1407 size_t len;
1408
1409 sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
1410 len = strlen(tbuf);
1411 if (p >= len)
1412 return 0;
1413 len -= p;
1414 if (len > count)
1415 len = count;
1416 if (copy_to_user(buf, (void*)(tbuf+p), len))
1417 return -EFAULT;
1418 *ppos += len;
1419 return len;
1420}
1421
1422static ssize_t write_flush(struct file *file, const char __user *buf,
1423 size_t count, loff_t *ppos,
1424 struct cache_detail *cd)
1425{
1426 char tbuf[20];
1427 char *bp, *ep;
1428
1429 if (*ppos || count > sizeof(tbuf)-1)
1430 return -EINVAL;
1431 if (copy_from_user(tbuf, buf, count))
1432 return -EFAULT;
1433 tbuf[count] = 0;
1434 simple_strtoul(tbuf, &ep, 0);
1435 if (*ep && *ep != '\n')
1436 return -EINVAL;
1437
1438 bp = tbuf;
1439 cd->flush_time = get_expiry(&bp);
1440 cd->nextcheck = seconds_since_boot();
1441 cache_flush();
1442
1443 *ppos += count;
1444 return count;
1445}
1446
1447static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1448 size_t count, loff_t *ppos)
1449{
1450 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1451
1452 return cache_read(filp, buf, count, ppos, cd);
1453}
1454
1455static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1456 size_t count, loff_t *ppos)
1457{
1458 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1459
1460 return cache_write(filp, buf, count, ppos, cd);
1461}
1462
1463static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1464{
1465 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1466
1467 return cache_poll(filp, wait, cd);
1468}
1469
1470static long cache_ioctl_procfs(struct file *filp,
1471 unsigned int cmd, unsigned long arg)
1472{
1473 struct inode *inode = filp->f_path.dentry->d_inode;
1474 struct cache_detail *cd = PDE(inode)->data;
1475
1476 return cache_ioctl(inode, filp, cmd, arg, cd);
1477}
1478
1479static int cache_open_procfs(struct inode *inode, struct file *filp)
1480{
1481 struct cache_detail *cd = PDE(inode)->data;
1482
1483 return cache_open(inode, filp, cd);
1484}
1485
1486static int cache_release_procfs(struct inode *inode, struct file *filp)
1487{
1488 struct cache_detail *cd = PDE(inode)->data;
1489
1490 return cache_release(inode, filp, cd);
1491}
1492
1493static const struct file_operations cache_file_operations_procfs = {
1494 .owner = THIS_MODULE,
1495 .llseek = no_llseek,
1496 .read = cache_read_procfs,
1497 .write = cache_write_procfs,
1498 .poll = cache_poll_procfs,
1499 .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1500 .open = cache_open_procfs,
1501 .release = cache_release_procfs,
1502};
1503
1504static int content_open_procfs(struct inode *inode, struct file *filp)
1505{
1506 struct cache_detail *cd = PDE(inode)->data;
1507
1508 return content_open(inode, filp, cd);
1509}
1510
1511static int content_release_procfs(struct inode *inode, struct file *filp)
1512{
1513 struct cache_detail *cd = PDE(inode)->data;
1514
1515 return content_release(inode, filp, cd);
1516}
1517
1518static const struct file_operations content_file_operations_procfs = {
1519 .open = content_open_procfs,
1520 .read = seq_read,
1521 .llseek = seq_lseek,
1522 .release = content_release_procfs,
1523};
1524
1525static int open_flush_procfs(struct inode *inode, struct file *filp)
1526{
1527 struct cache_detail *cd = PDE(inode)->data;
1528
1529 return open_flush(inode, filp, cd);
1530}
1531
1532static int release_flush_procfs(struct inode *inode, struct file *filp)
1533{
1534 struct cache_detail *cd = PDE(inode)->data;
1535
1536 return release_flush(inode, filp, cd);
1537}
1538
1539static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1540 size_t count, loff_t *ppos)
1541{
1542 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1543
1544 return read_flush(filp, buf, count, ppos, cd);
1545}
1546
1547static ssize_t write_flush_procfs(struct file *filp,
1548 const char __user *buf,
1549 size_t count, loff_t *ppos)
1550{
1551 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1552
1553 return write_flush(filp, buf, count, ppos, cd);
1554}
1555
1556static const struct file_operations cache_flush_operations_procfs = {
1557 .open = open_flush_procfs,
1558 .read = read_flush_procfs,
1559 .write = write_flush_procfs,
1560 .release = release_flush_procfs,
1561 .llseek = no_llseek,
1562};
1563
1564static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1565{
1566 struct sunrpc_net *sn;
1567
1568 if (cd->u.procfs.proc_ent == NULL)
1569 return;
1570 if (cd->u.procfs.flush_ent)
1571 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1572 if (cd->u.procfs.channel_ent)
1573 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1574 if (cd->u.procfs.content_ent)
1575 remove_proc_entry("content", cd->u.procfs.proc_ent);
1576 cd->u.procfs.proc_ent = NULL;
1577 sn = net_generic(net, sunrpc_net_id);
1578 remove_proc_entry(cd->name, sn->proc_net_rpc);
1579}
1580
1581#ifdef CONFIG_PROC_FS
1582static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1583{
1584 struct proc_dir_entry *p;
1585 struct sunrpc_net *sn;
1586
1587 sn = net_generic(net, sunrpc_net_id);
1588 cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1589 if (cd->u.procfs.proc_ent == NULL)
1590 goto out_nomem;
1591 cd->u.procfs.channel_ent = NULL;
1592 cd->u.procfs.content_ent = NULL;
1593
1594 p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1595 cd->u.procfs.proc_ent,
1596 &cache_flush_operations_procfs, cd);
1597 cd->u.procfs.flush_ent = p;
1598 if (p == NULL)
1599 goto out_nomem;
1600
1601 if (cd->cache_upcall || cd->cache_parse) {
1602 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1603 cd->u.procfs.proc_ent,
1604 &cache_file_operations_procfs, cd);
1605 cd->u.procfs.channel_ent = p;
1606 if (p == NULL)
1607 goto out_nomem;
1608 }
1609 if (cd->cache_show) {
1610 p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
1611 cd->u.procfs.proc_ent,
1612 &content_file_operations_procfs, cd);
1613 cd->u.procfs.content_ent = p;
1614 if (p == NULL)
1615 goto out_nomem;
1616 }
1617 return 0;
1618out_nomem:
1619 remove_cache_proc_entries(cd, net);
1620 return -ENOMEM;
1621}
1622#else /* CONFIG_PROC_FS */
1623static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1624{
1625 return 0;
1626}
1627#endif
1628
1629void __init cache_initialize(void)
1630{
1631 INIT_DELAYED_WORK_DEFERRABLE(&cache_cleaner, do_cache_clean);
1632}
1633
1634int cache_register_net(struct cache_detail *cd, struct net *net)
1635{
1636 int ret;
1637
1638 sunrpc_init_cache_detail(cd);
1639 ret = create_cache_proc_entries(cd, net);
1640 if (ret)
1641 sunrpc_destroy_cache_detail(cd);
1642 return ret;
1643}
1644
1645int cache_register(struct cache_detail *cd)
1646{
1647 return cache_register_net(cd, &init_net);
1648}
1649EXPORT_SYMBOL_GPL(cache_register);
1650
1651void cache_unregister_net(struct cache_detail *cd, struct net *net)
1652{
1653 remove_cache_proc_entries(cd, net);
1654 sunrpc_destroy_cache_detail(cd);
1655}
1656
1657void cache_unregister(struct cache_detail *cd)
1658{
1659 cache_unregister_net(cd, &init_net);
1660}
1661EXPORT_SYMBOL_GPL(cache_unregister);
1662
1663static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1664 size_t count, loff_t *ppos)
1665{
1666 struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1667
1668 return cache_read(filp, buf, count, ppos, cd);
1669}
1670
1671static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1672 size_t count, loff_t *ppos)
1673{
1674 struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1675
1676 return cache_write(filp, buf, count, ppos, cd);
1677}
1678
1679static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1680{
1681 struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1682
1683 return cache_poll(filp, wait, cd);
1684}
1685
1686static long cache_ioctl_pipefs(struct file *filp,
1687 unsigned int cmd, unsigned long arg)
1688{
1689 struct inode *inode = filp->f_dentry->d_inode;
1690 struct cache_detail *cd = RPC_I(inode)->private;
1691
1692 return cache_ioctl(inode, filp, cmd, arg, cd);
1693}
1694
1695static int cache_open_pipefs(struct inode *inode, struct file *filp)
1696{
1697 struct cache_detail *cd = RPC_I(inode)->private;
1698
1699 return cache_open(inode, filp, cd);
1700}
1701
1702static int cache_release_pipefs(struct inode *inode, struct file *filp)
1703{
1704 struct cache_detail *cd = RPC_I(inode)->private;
1705
1706 return cache_release(inode, filp, cd);
1707}
1708
1709const struct file_operations cache_file_operations_pipefs = {
1710 .owner = THIS_MODULE,
1711 .llseek = no_llseek,
1712 .read = cache_read_pipefs,
1713 .write = cache_write_pipefs,
1714 .poll = cache_poll_pipefs,
1715 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1716 .open = cache_open_pipefs,
1717 .release = cache_release_pipefs,
1718};
1719
1720static int content_open_pipefs(struct inode *inode, struct file *filp)
1721{
1722 struct cache_detail *cd = RPC_I(inode)->private;
1723
1724 return content_open(inode, filp, cd);
1725}
1726
1727static int content_release_pipefs(struct inode *inode, struct file *filp)
1728{
1729 struct cache_detail *cd = RPC_I(inode)->private;
1730
1731 return content_release(inode, filp, cd);
1732}
1733
1734const struct file_operations content_file_operations_pipefs = {
1735 .open = content_open_pipefs,
1736 .read = seq_read,
1737 .llseek = seq_lseek,
1738 .release = content_release_pipefs,
1739};
1740
1741static int open_flush_pipefs(struct inode *inode, struct file *filp)
1742{
1743 struct cache_detail *cd = RPC_I(inode)->private;
1744
1745 return open_flush(inode, filp, cd);
1746}
1747
1748static int release_flush_pipefs(struct inode *inode, struct file *filp)
1749{
1750 struct cache_detail *cd = RPC_I(inode)->private;
1751
1752 return release_flush(inode, filp, cd);
1753}
1754
1755static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1756 size_t count, loff_t *ppos)
1757{
1758 struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1759
1760 return read_flush(filp, buf, count, ppos, cd);
1761}
1762
1763static ssize_t write_flush_pipefs(struct file *filp,
1764 const char __user *buf,
1765 size_t count, loff_t *ppos)
1766{
1767 struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1768
1769 return write_flush(filp, buf, count, ppos, cd);
1770}
1771
1772const struct file_operations cache_flush_operations_pipefs = {
1773 .open = open_flush_pipefs,
1774 .read = read_flush_pipefs,
1775 .write = write_flush_pipefs,
1776 .release = release_flush_pipefs,
1777 .llseek = no_llseek,
1778};
1779
1780int sunrpc_cache_register_pipefs(struct dentry *parent,
1781 const char *name, mode_t umode,
1782 struct cache_detail *cd)
1783{
1784 struct qstr q;
1785 struct dentry *dir;
1786 int ret = 0;
1787
1788 sunrpc_init_cache_detail(cd);
1789 q.name = name;
1790 q.len = strlen(name);
1791 q.hash = full_name_hash(q.name, q.len);
1792 dir = rpc_create_cache_dir(parent, &q, umode, cd);
1793 if (!IS_ERR(dir))
1794 cd->u.pipefs.dir = dir;
1795 else {
1796 sunrpc_destroy_cache_detail(cd);
1797 ret = PTR_ERR(dir);
1798 }
1799 return ret;
1800}
1801EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1802
1803void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1804{
1805 rpc_remove_cache_dir(cd->u.pipefs.dir);
1806 cd->u.pipefs.dir = NULL;
1807 sunrpc_destroy_cache_detail(cd);
1808}
1809EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1810