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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 <trace/events/sunrpc.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, struct cache_detail *detail)
44{
45 time64_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 void cache_fresh_unlocked(struct cache_head *head,
57 struct cache_detail *detail);
58
59static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
60 struct cache_head *key,
61 int hash)
62{
63 struct hlist_head *head = &detail->hash_table[hash];
64 struct cache_head *tmp;
65
66 rcu_read_lock();
67 hlist_for_each_entry_rcu(tmp, head, cache_list) {
68 if (!detail->match(tmp, key))
69 continue;
70 if (test_bit(CACHE_VALID, &tmp->flags) &&
71 cache_is_expired(detail, tmp))
72 continue;
73 tmp = cache_get_rcu(tmp);
74 rcu_read_unlock();
75 return tmp;
76 }
77 rcu_read_unlock();
78 return NULL;
79}
80
81static void sunrpc_begin_cache_remove_entry(struct cache_head *ch,
82 struct cache_detail *cd)
83{
84 /* Must be called under cd->hash_lock */
85 hlist_del_init_rcu(&ch->cache_list);
86 set_bit(CACHE_CLEANED, &ch->flags);
87 cd->entries --;
88}
89
90static void sunrpc_end_cache_remove_entry(struct cache_head *ch,
91 struct cache_detail *cd)
92{
93 cache_fresh_unlocked(ch, cd);
94 cache_put(ch, cd);
95}
96
97static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
98 struct cache_head *key,
99 int hash)
100{
101 struct cache_head *new, *tmp, *freeme = NULL;
102 struct hlist_head *head = &detail->hash_table[hash];
103
104 new = detail->alloc();
105 if (!new)
106 return NULL;
107 /* must fully initialise 'new', else
108 * we might get lose if we need to
109 * cache_put it soon.
110 */
111 cache_init(new, detail);
112 detail->init(new, key);
113
114 spin_lock(&detail->hash_lock);
115
116 /* check if entry appeared while we slept */
117 hlist_for_each_entry_rcu(tmp, head, cache_list,
118 lockdep_is_held(&detail->hash_lock)) {
119 if (!detail->match(tmp, key))
120 continue;
121 if (test_bit(CACHE_VALID, &tmp->flags) &&
122 cache_is_expired(detail, tmp)) {
123 sunrpc_begin_cache_remove_entry(tmp, detail);
124 trace_cache_entry_expired(detail, tmp);
125 freeme = tmp;
126 break;
127 }
128 cache_get(tmp);
129 spin_unlock(&detail->hash_lock);
130 cache_put(new, detail);
131 return tmp;
132 }
133
134 hlist_add_head_rcu(&new->cache_list, head);
135 detail->entries++;
136 cache_get(new);
137 spin_unlock(&detail->hash_lock);
138
139 if (freeme)
140 sunrpc_end_cache_remove_entry(freeme, detail);
141 return new;
142}
143
144struct cache_head *sunrpc_cache_lookup_rcu(struct cache_detail *detail,
145 struct cache_head *key, int hash)
146{
147 struct cache_head *ret;
148
149 ret = sunrpc_cache_find_rcu(detail, key, hash);
150 if (ret)
151 return ret;
152 /* Didn't find anything, insert an empty entry */
153 return sunrpc_cache_add_entry(detail, key, hash);
154}
155EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu);
156
157static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
158
159static void cache_fresh_locked(struct cache_head *head, time64_t expiry,
160 struct cache_detail *detail)
161{
162 time64_t now = seconds_since_boot();
163 if (now <= detail->flush_time)
164 /* ensure it isn't immediately treated as expired */
165 now = detail->flush_time + 1;
166 head->expiry_time = expiry;
167 head->last_refresh = now;
168 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
169 set_bit(CACHE_VALID, &head->flags);
170}
171
172static void cache_fresh_unlocked(struct cache_head *head,
173 struct cache_detail *detail)
174{
175 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
176 cache_revisit_request(head);
177 cache_dequeue(detail, head);
178 }
179}
180
181static void cache_make_negative(struct cache_detail *detail,
182 struct cache_head *h)
183{
184 set_bit(CACHE_NEGATIVE, &h->flags);
185 trace_cache_entry_make_negative(detail, h);
186}
187
188static void cache_entry_update(struct cache_detail *detail,
189 struct cache_head *h,
190 struct cache_head *new)
191{
192 if (!test_bit(CACHE_NEGATIVE, &new->flags)) {
193 detail->update(h, new);
194 trace_cache_entry_update(detail, h);
195 } else {
196 cache_make_negative(detail, h);
197 }
198}
199
200struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
201 struct cache_head *new, struct cache_head *old, int hash)
202{
203 /* The 'old' entry is to be replaced by 'new'.
204 * If 'old' is not VALID, we update it directly,
205 * otherwise we need to replace it
206 */
207 struct cache_head *tmp;
208
209 if (!test_bit(CACHE_VALID, &old->flags)) {
210 spin_lock(&detail->hash_lock);
211 if (!test_bit(CACHE_VALID, &old->flags)) {
212 cache_entry_update(detail, old, new);
213 cache_fresh_locked(old, new->expiry_time, detail);
214 spin_unlock(&detail->hash_lock);
215 cache_fresh_unlocked(old, detail);
216 return old;
217 }
218 spin_unlock(&detail->hash_lock);
219 }
220 /* We need to insert a new entry */
221 tmp = detail->alloc();
222 if (!tmp) {
223 cache_put(old, detail);
224 return NULL;
225 }
226 cache_init(tmp, detail);
227 detail->init(tmp, old);
228
229 spin_lock(&detail->hash_lock);
230 cache_entry_update(detail, tmp, new);
231 hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
232 detail->entries++;
233 cache_get(tmp);
234 cache_fresh_locked(tmp, new->expiry_time, detail);
235 cache_fresh_locked(old, 0, detail);
236 spin_unlock(&detail->hash_lock);
237 cache_fresh_unlocked(tmp, detail);
238 cache_fresh_unlocked(old, detail);
239 cache_put(old, detail);
240 return tmp;
241}
242EXPORT_SYMBOL_GPL(sunrpc_cache_update);
243
244static inline int cache_is_valid(struct cache_head *h)
245{
246 if (!test_bit(CACHE_VALID, &h->flags))
247 return -EAGAIN;
248 else {
249 /* entry is valid */
250 if (test_bit(CACHE_NEGATIVE, &h->flags))
251 return -ENOENT;
252 else {
253 /*
254 * In combination with write barrier in
255 * sunrpc_cache_update, ensures that anyone
256 * using the cache entry after this sees the
257 * updated contents:
258 */
259 smp_rmb();
260 return 0;
261 }
262 }
263}
264
265static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
266{
267 int rv;
268
269 spin_lock(&detail->hash_lock);
270 rv = cache_is_valid(h);
271 if (rv == -EAGAIN) {
272 cache_make_negative(detail, h);
273 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
274 detail);
275 rv = -ENOENT;
276 }
277 spin_unlock(&detail->hash_lock);
278 cache_fresh_unlocked(h, detail);
279 return rv;
280}
281
282/*
283 * This is the generic cache management routine for all
284 * the authentication caches.
285 * It checks the currency of a cache item and will (later)
286 * initiate an upcall to fill it if needed.
287 *
288 *
289 * Returns 0 if the cache_head can be used, or cache_puts it and returns
290 * -EAGAIN if upcall is pending and request has been queued
291 * -ETIMEDOUT if upcall failed or request could not be queue or
292 * upcall completed but item is still invalid (implying that
293 * the cache item has been replaced with a newer one).
294 * -ENOENT if cache entry was negative
295 */
296int cache_check(struct cache_detail *detail,
297 struct cache_head *h, struct cache_req *rqstp)
298{
299 int rv;
300 time64_t refresh_age, age;
301
302 /* First decide return status as best we can */
303 rv = cache_is_valid(h);
304
305 /* now see if we want to start an upcall */
306 refresh_age = (h->expiry_time - h->last_refresh);
307 age = seconds_since_boot() - h->last_refresh;
308
309 if (rqstp == NULL) {
310 if (rv == -EAGAIN)
311 rv = -ENOENT;
312 } else if (rv == -EAGAIN ||
313 (h->expiry_time != 0 && age > refresh_age/2)) {
314 dprintk("RPC: Want update, refage=%lld, age=%lld\n",
315 refresh_age, age);
316 switch (detail->cache_upcall(detail, h)) {
317 case -EINVAL:
318 rv = try_to_negate_entry(detail, h);
319 break;
320 case -EAGAIN:
321 cache_fresh_unlocked(h, detail);
322 break;
323 }
324 }
325
326 if (rv == -EAGAIN) {
327 if (!cache_defer_req(rqstp, h)) {
328 /*
329 * Request was not deferred; handle it as best
330 * we can ourselves:
331 */
332 rv = cache_is_valid(h);
333 if (rv == -EAGAIN)
334 rv = -ETIMEDOUT;
335 }
336 }
337 if (rv)
338 cache_put(h, detail);
339 return rv;
340}
341EXPORT_SYMBOL_GPL(cache_check);
342
343/*
344 * caches need to be periodically cleaned.
345 * For this we maintain a list of cache_detail and
346 * a current pointer into that list and into the table
347 * for that entry.
348 *
349 * Each time cache_clean is called it finds the next non-empty entry
350 * in the current table and walks the list in that entry
351 * looking for entries that can be removed.
352 *
353 * An entry gets removed if:
354 * - The expiry is before current time
355 * - The last_refresh time is before the flush_time for that cache
356 *
357 * later we might drop old entries with non-NEVER expiry if that table
358 * is getting 'full' for some definition of 'full'
359 *
360 * The question of "how often to scan a table" is an interesting one
361 * and is answered in part by the use of the "nextcheck" field in the
362 * cache_detail.
363 * When a scan of a table begins, the nextcheck field is set to a time
364 * that is well into the future.
365 * While scanning, if an expiry time is found that is earlier than the
366 * current nextcheck time, nextcheck is set to that expiry time.
367 * If the flush_time is ever set to a time earlier than the nextcheck
368 * time, the nextcheck time is then set to that flush_time.
369 *
370 * A table is then only scanned if the current time is at least
371 * the nextcheck time.
372 *
373 */
374
375static LIST_HEAD(cache_list);
376static DEFINE_SPINLOCK(cache_list_lock);
377static struct cache_detail *current_detail;
378static int current_index;
379
380static void do_cache_clean(struct work_struct *work);
381static struct delayed_work cache_cleaner;
382
383void sunrpc_init_cache_detail(struct cache_detail *cd)
384{
385 spin_lock_init(&cd->hash_lock);
386 INIT_LIST_HEAD(&cd->queue);
387 spin_lock(&cache_list_lock);
388 cd->nextcheck = 0;
389 cd->entries = 0;
390 atomic_set(&cd->writers, 0);
391 cd->last_close = 0;
392 cd->last_warn = -1;
393 list_add(&cd->others, &cache_list);
394 spin_unlock(&cache_list_lock);
395
396 /* start the cleaning process */
397 queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
398}
399EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
400
401void sunrpc_destroy_cache_detail(struct cache_detail *cd)
402{
403 cache_purge(cd);
404 spin_lock(&cache_list_lock);
405 spin_lock(&cd->hash_lock);
406 if (current_detail == cd)
407 current_detail = NULL;
408 list_del_init(&cd->others);
409 spin_unlock(&cd->hash_lock);
410 spin_unlock(&cache_list_lock);
411 if (list_empty(&cache_list)) {
412 /* module must be being unloaded so its safe to kill the worker */
413 cancel_delayed_work_sync(&cache_cleaner);
414 }
415}
416EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
417
418/* clean cache tries to find something to clean
419 * and cleans it.
420 * It returns 1 if it cleaned something,
421 * 0 if it didn't find anything this time
422 * -1 if it fell off the end of the list.
423 */
424static int cache_clean(void)
425{
426 int rv = 0;
427 struct list_head *next;
428
429 spin_lock(&cache_list_lock);
430
431 /* find a suitable table if we don't already have one */
432 while (current_detail == NULL ||
433 current_index >= current_detail->hash_size) {
434 if (current_detail)
435 next = current_detail->others.next;
436 else
437 next = cache_list.next;
438 if (next == &cache_list) {
439 current_detail = NULL;
440 spin_unlock(&cache_list_lock);
441 return -1;
442 }
443 current_detail = list_entry(next, struct cache_detail, others);
444 if (current_detail->nextcheck > seconds_since_boot())
445 current_index = current_detail->hash_size;
446 else {
447 current_index = 0;
448 current_detail->nextcheck = seconds_since_boot()+30*60;
449 }
450 }
451
452 /* find a non-empty bucket in the table */
453 while (current_detail &&
454 current_index < current_detail->hash_size &&
455 hlist_empty(¤t_detail->hash_table[current_index]))
456 current_index++;
457
458 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
459
460 if (current_detail && current_index < current_detail->hash_size) {
461 struct cache_head *ch = NULL;
462 struct cache_detail *d;
463 struct hlist_head *head;
464 struct hlist_node *tmp;
465
466 spin_lock(¤t_detail->hash_lock);
467
468 /* Ok, now to clean this strand */
469
470 head = ¤t_detail->hash_table[current_index];
471 hlist_for_each_entry_safe(ch, tmp, head, cache_list) {
472 if (current_detail->nextcheck > ch->expiry_time)
473 current_detail->nextcheck = ch->expiry_time+1;
474 if (!cache_is_expired(current_detail, ch))
475 continue;
476
477 sunrpc_begin_cache_remove_entry(ch, current_detail);
478 trace_cache_entry_expired(current_detail, ch);
479 rv = 1;
480 break;
481 }
482
483 spin_unlock(¤t_detail->hash_lock);
484 d = current_detail;
485 if (!ch)
486 current_index ++;
487 spin_unlock(&cache_list_lock);
488 if (ch)
489 sunrpc_end_cache_remove_entry(ch, d);
490 } else
491 spin_unlock(&cache_list_lock);
492
493 return rv;
494}
495
496/*
497 * We want to regularly clean the cache, so we need to schedule some work ...
498 */
499static void do_cache_clean(struct work_struct *work)
500{
501 int delay = 5;
502 if (cache_clean() == -1)
503 delay = round_jiffies_relative(30*HZ);
504
505 if (list_empty(&cache_list))
506 delay = 0;
507
508 if (delay)
509 queue_delayed_work(system_power_efficient_wq,
510 &cache_cleaner, delay);
511}
512
513
514/*
515 * Clean all caches promptly. This just calls cache_clean
516 * repeatedly until we are sure that every cache has had a chance to
517 * be fully cleaned
518 */
519void cache_flush(void)
520{
521 while (cache_clean() != -1)
522 cond_resched();
523 while (cache_clean() != -1)
524 cond_resched();
525}
526EXPORT_SYMBOL_GPL(cache_flush);
527
528void cache_purge(struct cache_detail *detail)
529{
530 struct cache_head *ch = NULL;
531 struct hlist_head *head = NULL;
532 int i = 0;
533
534 spin_lock(&detail->hash_lock);
535 if (!detail->entries) {
536 spin_unlock(&detail->hash_lock);
537 return;
538 }
539
540 dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name);
541 for (i = 0; i < detail->hash_size; i++) {
542 head = &detail->hash_table[i];
543 while (!hlist_empty(head)) {
544 ch = hlist_entry(head->first, struct cache_head,
545 cache_list);
546 sunrpc_begin_cache_remove_entry(ch, detail);
547 spin_unlock(&detail->hash_lock);
548 sunrpc_end_cache_remove_entry(ch, detail);
549 spin_lock(&detail->hash_lock);
550 }
551 }
552 spin_unlock(&detail->hash_lock);
553}
554EXPORT_SYMBOL_GPL(cache_purge);
555
556
557/*
558 * Deferral and Revisiting of Requests.
559 *
560 * If a cache lookup finds a pending entry, we
561 * need to defer the request and revisit it later.
562 * All deferred requests are stored in a hash table,
563 * indexed by "struct cache_head *".
564 * As it may be wasteful to store a whole request
565 * structure, we allow the request to provide a
566 * deferred form, which must contain a
567 * 'struct cache_deferred_req'
568 * This cache_deferred_req contains a method to allow
569 * it to be revisited when cache info is available
570 */
571
572#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
573#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
574
575#define DFR_MAX 300 /* ??? */
576
577static DEFINE_SPINLOCK(cache_defer_lock);
578static LIST_HEAD(cache_defer_list);
579static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
580static int cache_defer_cnt;
581
582static void __unhash_deferred_req(struct cache_deferred_req *dreq)
583{
584 hlist_del_init(&dreq->hash);
585 if (!list_empty(&dreq->recent)) {
586 list_del_init(&dreq->recent);
587 cache_defer_cnt--;
588 }
589}
590
591static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
592{
593 int hash = DFR_HASH(item);
594
595 INIT_LIST_HEAD(&dreq->recent);
596 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
597}
598
599static void setup_deferral(struct cache_deferred_req *dreq,
600 struct cache_head *item,
601 int count_me)
602{
603
604 dreq->item = item;
605
606 spin_lock(&cache_defer_lock);
607
608 __hash_deferred_req(dreq, item);
609
610 if (count_me) {
611 cache_defer_cnt++;
612 list_add(&dreq->recent, &cache_defer_list);
613 }
614
615 spin_unlock(&cache_defer_lock);
616
617}
618
619struct thread_deferred_req {
620 struct cache_deferred_req handle;
621 struct completion completion;
622};
623
624static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
625{
626 struct thread_deferred_req *dr =
627 container_of(dreq, struct thread_deferred_req, handle);
628 complete(&dr->completion);
629}
630
631static void cache_wait_req(struct cache_req *req, struct cache_head *item)
632{
633 struct thread_deferred_req sleeper;
634 struct cache_deferred_req *dreq = &sleeper.handle;
635
636 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
637 dreq->revisit = cache_restart_thread;
638
639 setup_deferral(dreq, item, 0);
640
641 if (!test_bit(CACHE_PENDING, &item->flags) ||
642 wait_for_completion_interruptible_timeout(
643 &sleeper.completion, req->thread_wait) <= 0) {
644 /* The completion wasn't completed, so we need
645 * to clean up
646 */
647 spin_lock(&cache_defer_lock);
648 if (!hlist_unhashed(&sleeper.handle.hash)) {
649 __unhash_deferred_req(&sleeper.handle);
650 spin_unlock(&cache_defer_lock);
651 } else {
652 /* cache_revisit_request already removed
653 * this from the hash table, but hasn't
654 * called ->revisit yet. It will very soon
655 * and we need to wait for it.
656 */
657 spin_unlock(&cache_defer_lock);
658 wait_for_completion(&sleeper.completion);
659 }
660 }
661}
662
663static void cache_limit_defers(void)
664{
665 /* Make sure we haven't exceed the limit of allowed deferred
666 * requests.
667 */
668 struct cache_deferred_req *discard = NULL;
669
670 if (cache_defer_cnt <= DFR_MAX)
671 return;
672
673 spin_lock(&cache_defer_lock);
674
675 /* Consider removing either the first or the last */
676 if (cache_defer_cnt > DFR_MAX) {
677 if (prandom_u32() & 1)
678 discard = list_entry(cache_defer_list.next,
679 struct cache_deferred_req, recent);
680 else
681 discard = list_entry(cache_defer_list.prev,
682 struct cache_deferred_req, recent);
683 __unhash_deferred_req(discard);
684 }
685 spin_unlock(&cache_defer_lock);
686 if (discard)
687 discard->revisit(discard, 1);
688}
689
690/* Return true if and only if a deferred request is queued. */
691static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
692{
693 struct cache_deferred_req *dreq;
694
695 if (req->thread_wait) {
696 cache_wait_req(req, item);
697 if (!test_bit(CACHE_PENDING, &item->flags))
698 return false;
699 }
700 dreq = req->defer(req);
701 if (dreq == NULL)
702 return false;
703 setup_deferral(dreq, item, 1);
704 if (!test_bit(CACHE_PENDING, &item->flags))
705 /* Bit could have been cleared before we managed to
706 * set up the deferral, so need to revisit just in case
707 */
708 cache_revisit_request(item);
709
710 cache_limit_defers();
711 return true;
712}
713
714static void cache_revisit_request(struct cache_head *item)
715{
716 struct cache_deferred_req *dreq;
717 struct list_head pending;
718 struct hlist_node *tmp;
719 int hash = DFR_HASH(item);
720
721 INIT_LIST_HEAD(&pending);
722 spin_lock(&cache_defer_lock);
723
724 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
725 if (dreq->item == item) {
726 __unhash_deferred_req(dreq);
727 list_add(&dreq->recent, &pending);
728 }
729
730 spin_unlock(&cache_defer_lock);
731
732 while (!list_empty(&pending)) {
733 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
734 list_del_init(&dreq->recent);
735 dreq->revisit(dreq, 0);
736 }
737}
738
739void cache_clean_deferred(void *owner)
740{
741 struct cache_deferred_req *dreq, *tmp;
742 struct list_head pending;
743
744
745 INIT_LIST_HEAD(&pending);
746 spin_lock(&cache_defer_lock);
747
748 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
749 if (dreq->owner == owner) {
750 __unhash_deferred_req(dreq);
751 list_add(&dreq->recent, &pending);
752 }
753 }
754 spin_unlock(&cache_defer_lock);
755
756 while (!list_empty(&pending)) {
757 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
758 list_del_init(&dreq->recent);
759 dreq->revisit(dreq, 1);
760 }
761}
762
763/*
764 * communicate with user-space
765 *
766 * We have a magic /proc file - /proc/net/rpc/<cachename>/channel.
767 * On read, you get a full request, or block.
768 * On write, an update request is processed.
769 * Poll works if anything to read, and always allows write.
770 *
771 * Implemented by linked list of requests. Each open file has
772 * a ->private that also exists in this list. New requests are added
773 * to the end and may wakeup and preceding readers.
774 * New readers are added to the head. If, on read, an item is found with
775 * CACHE_UPCALLING clear, we free it from the list.
776 *
777 */
778
779static DEFINE_SPINLOCK(queue_lock);
780static DEFINE_MUTEX(queue_io_mutex);
781
782struct cache_queue {
783 struct list_head list;
784 int reader; /* if 0, then request */
785};
786struct cache_request {
787 struct cache_queue q;
788 struct cache_head *item;
789 char * buf;
790 int len;
791 int readers;
792};
793struct cache_reader {
794 struct cache_queue q;
795 int offset; /* if non-0, we have a refcnt on next request */
796};
797
798static int cache_request(struct cache_detail *detail,
799 struct cache_request *crq)
800{
801 char *bp = crq->buf;
802 int len = PAGE_SIZE;
803
804 detail->cache_request(detail, crq->item, &bp, &len);
805 if (len < 0)
806 return -EAGAIN;
807 return PAGE_SIZE - len;
808}
809
810static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
811 loff_t *ppos, struct cache_detail *cd)
812{
813 struct cache_reader *rp = filp->private_data;
814 struct cache_request *rq;
815 struct inode *inode = file_inode(filp);
816 int err;
817
818 if (count == 0)
819 return 0;
820
821 inode_lock(inode); /* protect against multiple concurrent
822 * readers on this file */
823 again:
824 spin_lock(&queue_lock);
825 /* need to find next request */
826 while (rp->q.list.next != &cd->queue &&
827 list_entry(rp->q.list.next, struct cache_queue, list)
828 ->reader) {
829 struct list_head *next = rp->q.list.next;
830 list_move(&rp->q.list, next);
831 }
832 if (rp->q.list.next == &cd->queue) {
833 spin_unlock(&queue_lock);
834 inode_unlock(inode);
835 WARN_ON_ONCE(rp->offset);
836 return 0;
837 }
838 rq = container_of(rp->q.list.next, struct cache_request, q.list);
839 WARN_ON_ONCE(rq->q.reader);
840 if (rp->offset == 0)
841 rq->readers++;
842 spin_unlock(&queue_lock);
843
844 if (rq->len == 0) {
845 err = cache_request(cd, rq);
846 if (err < 0)
847 goto out;
848 rq->len = err;
849 }
850
851 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
852 err = -EAGAIN;
853 spin_lock(&queue_lock);
854 list_move(&rp->q.list, &rq->q.list);
855 spin_unlock(&queue_lock);
856 } else {
857 if (rp->offset + count > rq->len)
858 count = rq->len - rp->offset;
859 err = -EFAULT;
860 if (copy_to_user(buf, rq->buf + rp->offset, count))
861 goto out;
862 rp->offset += count;
863 if (rp->offset >= rq->len) {
864 rp->offset = 0;
865 spin_lock(&queue_lock);
866 list_move(&rp->q.list, &rq->q.list);
867 spin_unlock(&queue_lock);
868 }
869 err = 0;
870 }
871 out:
872 if (rp->offset == 0) {
873 /* need to release rq */
874 spin_lock(&queue_lock);
875 rq->readers--;
876 if (rq->readers == 0 &&
877 !test_bit(CACHE_PENDING, &rq->item->flags)) {
878 list_del(&rq->q.list);
879 spin_unlock(&queue_lock);
880 cache_put(rq->item, cd);
881 kfree(rq->buf);
882 kfree(rq);
883 } else
884 spin_unlock(&queue_lock);
885 }
886 if (err == -EAGAIN)
887 goto again;
888 inode_unlock(inode);
889 return err ? err : count;
890}
891
892static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
893 size_t count, struct cache_detail *cd)
894{
895 ssize_t ret;
896
897 if (count == 0)
898 return -EINVAL;
899 if (copy_from_user(kaddr, buf, count))
900 return -EFAULT;
901 kaddr[count] = '\0';
902 ret = cd->cache_parse(cd, kaddr, count);
903 if (!ret)
904 ret = count;
905 return ret;
906}
907
908static ssize_t cache_slow_downcall(const char __user *buf,
909 size_t count, struct cache_detail *cd)
910{
911 static char write_buf[8192]; /* protected by queue_io_mutex */
912 ssize_t ret = -EINVAL;
913
914 if (count >= sizeof(write_buf))
915 goto out;
916 mutex_lock(&queue_io_mutex);
917 ret = cache_do_downcall(write_buf, buf, count, cd);
918 mutex_unlock(&queue_io_mutex);
919out:
920 return ret;
921}
922
923static ssize_t cache_downcall(struct address_space *mapping,
924 const char __user *buf,
925 size_t count, struct cache_detail *cd)
926{
927 struct page *page;
928 char *kaddr;
929 ssize_t ret = -ENOMEM;
930
931 if (count >= PAGE_SIZE)
932 goto out_slow;
933
934 page = find_or_create_page(mapping, 0, GFP_KERNEL);
935 if (!page)
936 goto out_slow;
937
938 kaddr = kmap(page);
939 ret = cache_do_downcall(kaddr, buf, count, cd);
940 kunmap(page);
941 unlock_page(page);
942 put_page(page);
943 return ret;
944out_slow:
945 return cache_slow_downcall(buf, count, cd);
946}
947
948static ssize_t cache_write(struct file *filp, const char __user *buf,
949 size_t count, loff_t *ppos,
950 struct cache_detail *cd)
951{
952 struct address_space *mapping = filp->f_mapping;
953 struct inode *inode = file_inode(filp);
954 ssize_t ret = -EINVAL;
955
956 if (!cd->cache_parse)
957 goto out;
958
959 inode_lock(inode);
960 ret = cache_downcall(mapping, buf, count, cd);
961 inode_unlock(inode);
962out:
963 return ret;
964}
965
966static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
967
968static __poll_t cache_poll(struct file *filp, poll_table *wait,
969 struct cache_detail *cd)
970{
971 __poll_t mask;
972 struct cache_reader *rp = filp->private_data;
973 struct cache_queue *cq;
974
975 poll_wait(filp, &queue_wait, wait);
976
977 /* alway allow write */
978 mask = EPOLLOUT | EPOLLWRNORM;
979
980 if (!rp)
981 return mask;
982
983 spin_lock(&queue_lock);
984
985 for (cq= &rp->q; &cq->list != &cd->queue;
986 cq = list_entry(cq->list.next, struct cache_queue, list))
987 if (!cq->reader) {
988 mask |= EPOLLIN | EPOLLRDNORM;
989 break;
990 }
991 spin_unlock(&queue_lock);
992 return mask;
993}
994
995static int cache_ioctl(struct inode *ino, struct file *filp,
996 unsigned int cmd, unsigned long arg,
997 struct cache_detail *cd)
998{
999 int len = 0;
1000 struct cache_reader *rp = filp->private_data;
1001 struct cache_queue *cq;
1002
1003 if (cmd != FIONREAD || !rp)
1004 return -EINVAL;
1005
1006 spin_lock(&queue_lock);
1007
1008 /* only find the length remaining in current request,
1009 * or the length of the next request
1010 */
1011 for (cq= &rp->q; &cq->list != &cd->queue;
1012 cq = list_entry(cq->list.next, struct cache_queue, list))
1013 if (!cq->reader) {
1014 struct cache_request *cr =
1015 container_of(cq, struct cache_request, q);
1016 len = cr->len - rp->offset;
1017 break;
1018 }
1019 spin_unlock(&queue_lock);
1020
1021 return put_user(len, (int __user *)arg);
1022}
1023
1024static int cache_open(struct inode *inode, struct file *filp,
1025 struct cache_detail *cd)
1026{
1027 struct cache_reader *rp = NULL;
1028
1029 if (!cd || !try_module_get(cd->owner))
1030 return -EACCES;
1031 nonseekable_open(inode, filp);
1032 if (filp->f_mode & FMODE_READ) {
1033 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
1034 if (!rp) {
1035 module_put(cd->owner);
1036 return -ENOMEM;
1037 }
1038 rp->offset = 0;
1039 rp->q.reader = 1;
1040
1041 spin_lock(&queue_lock);
1042 list_add(&rp->q.list, &cd->queue);
1043 spin_unlock(&queue_lock);
1044 }
1045 if (filp->f_mode & FMODE_WRITE)
1046 atomic_inc(&cd->writers);
1047 filp->private_data = rp;
1048 return 0;
1049}
1050
1051static int cache_release(struct inode *inode, struct file *filp,
1052 struct cache_detail *cd)
1053{
1054 struct cache_reader *rp = filp->private_data;
1055
1056 if (rp) {
1057 spin_lock(&queue_lock);
1058 if (rp->offset) {
1059 struct cache_queue *cq;
1060 for (cq= &rp->q; &cq->list != &cd->queue;
1061 cq = list_entry(cq->list.next, struct cache_queue, list))
1062 if (!cq->reader) {
1063 container_of(cq, struct cache_request, q)
1064 ->readers--;
1065 break;
1066 }
1067 rp->offset = 0;
1068 }
1069 list_del(&rp->q.list);
1070 spin_unlock(&queue_lock);
1071
1072 filp->private_data = NULL;
1073 kfree(rp);
1074
1075 }
1076 if (filp->f_mode & FMODE_WRITE) {
1077 atomic_dec(&cd->writers);
1078 cd->last_close = seconds_since_boot();
1079 }
1080 module_put(cd->owner);
1081 return 0;
1082}
1083
1084
1085
1086static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1087{
1088 struct cache_queue *cq, *tmp;
1089 struct cache_request *cr;
1090 struct list_head dequeued;
1091
1092 INIT_LIST_HEAD(&dequeued);
1093 spin_lock(&queue_lock);
1094 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1095 if (!cq->reader) {
1096 cr = container_of(cq, struct cache_request, q);
1097 if (cr->item != ch)
1098 continue;
1099 if (test_bit(CACHE_PENDING, &ch->flags))
1100 /* Lost a race and it is pending again */
1101 break;
1102 if (cr->readers != 0)
1103 continue;
1104 list_move(&cr->q.list, &dequeued);
1105 }
1106 spin_unlock(&queue_lock);
1107 while (!list_empty(&dequeued)) {
1108 cr = list_entry(dequeued.next, struct cache_request, q.list);
1109 list_del(&cr->q.list);
1110 cache_put(cr->item, detail);
1111 kfree(cr->buf);
1112 kfree(cr);
1113 }
1114}
1115
1116/*
1117 * Support routines for text-based upcalls.
1118 * Fields are separated by spaces.
1119 * Fields are either mangled to quote space tab newline slosh with slosh
1120 * or a hexified with a leading \x
1121 * Record is terminated with newline.
1122 *
1123 */
1124
1125void qword_add(char **bpp, int *lp, char *str)
1126{
1127 char *bp = *bpp;
1128 int len = *lp;
1129 int ret;
1130
1131 if (len < 0) return;
1132
1133 ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
1134 if (ret >= len) {
1135 bp += len;
1136 len = -1;
1137 } else {
1138 bp += ret;
1139 len -= ret;
1140 *bp++ = ' ';
1141 len--;
1142 }
1143 *bpp = bp;
1144 *lp = len;
1145}
1146EXPORT_SYMBOL_GPL(qword_add);
1147
1148void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1149{
1150 char *bp = *bpp;
1151 int len = *lp;
1152
1153 if (len < 0) return;
1154
1155 if (len > 2) {
1156 *bp++ = '\\';
1157 *bp++ = 'x';
1158 len -= 2;
1159 while (blen && len >= 2) {
1160 bp = hex_byte_pack(bp, *buf++);
1161 len -= 2;
1162 blen--;
1163 }
1164 }
1165 if (blen || len<1) len = -1;
1166 else {
1167 *bp++ = ' ';
1168 len--;
1169 }
1170 *bpp = bp;
1171 *lp = len;
1172}
1173EXPORT_SYMBOL_GPL(qword_addhex);
1174
1175static void warn_no_listener(struct cache_detail *detail)
1176{
1177 if (detail->last_warn != detail->last_close) {
1178 detail->last_warn = detail->last_close;
1179 if (detail->warn_no_listener)
1180 detail->warn_no_listener(detail, detail->last_close != 0);
1181 }
1182}
1183
1184static bool cache_listeners_exist(struct cache_detail *detail)
1185{
1186 if (atomic_read(&detail->writers))
1187 return true;
1188 if (detail->last_close == 0)
1189 /* This cache was never opened */
1190 return false;
1191 if (detail->last_close < seconds_since_boot() - 30)
1192 /*
1193 * We allow for the possibility that someone might
1194 * restart a userspace daemon without restarting the
1195 * server; but after 30 seconds, we give up.
1196 */
1197 return false;
1198 return true;
1199}
1200
1201/*
1202 * register an upcall request to user-space and queue it up for read() by the
1203 * upcall daemon.
1204 *
1205 * Each request is at most one page long.
1206 */
1207static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1208{
1209 char *buf;
1210 struct cache_request *crq;
1211 int ret = 0;
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 trace_cache_entry_upcall(detail, h);
1236 } else
1237 /* Lost a race, no longer PENDING, so don't enqueue */
1238 ret = -EAGAIN;
1239 spin_unlock(&queue_lock);
1240 wake_up(&queue_wait);
1241 if (ret == -EAGAIN) {
1242 kfree(buf);
1243 kfree(crq);
1244 }
1245 return ret;
1246}
1247
1248int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1249{
1250 if (test_and_set_bit(CACHE_PENDING, &h->flags))
1251 return 0;
1252 return cache_pipe_upcall(detail, h);
1253}
1254EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1255
1256int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
1257 struct cache_head *h)
1258{
1259 if (!cache_listeners_exist(detail)) {
1260 warn_no_listener(detail);
1261 trace_cache_entry_no_listener(detail, h);
1262 return -EINVAL;
1263 }
1264 return sunrpc_cache_pipe_upcall(detail, h);
1265}
1266EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
1267
1268/*
1269 * parse a message from user-space and pass it
1270 * to an appropriate cache
1271 * Messages are, like requests, separated into fields by
1272 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1273 *
1274 * Message is
1275 * reply cachename expiry key ... content....
1276 *
1277 * key and content are both parsed by cache
1278 */
1279
1280int qword_get(char **bpp, char *dest, int bufsize)
1281{
1282 /* return bytes copied, or -1 on error */
1283 char *bp = *bpp;
1284 int len = 0;
1285
1286 while (*bp == ' ') bp++;
1287
1288 if (bp[0] == '\\' && bp[1] == 'x') {
1289 /* HEX STRING */
1290 bp += 2;
1291 while (len < bufsize - 1) {
1292 int h, l;
1293
1294 h = hex_to_bin(bp[0]);
1295 if (h < 0)
1296 break;
1297
1298 l = hex_to_bin(bp[1]);
1299 if (l < 0)
1300 break;
1301
1302 *dest++ = (h << 4) | l;
1303 bp += 2;
1304 len++;
1305 }
1306 } else {
1307 /* text with \nnn octal quoting */
1308 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1309 if (*bp == '\\' &&
1310 isodigit(bp[1]) && (bp[1] <= '3') &&
1311 isodigit(bp[2]) &&
1312 isodigit(bp[3])) {
1313 int byte = (*++bp -'0');
1314 bp++;
1315 byte = (byte << 3) | (*bp++ - '0');
1316 byte = (byte << 3) | (*bp++ - '0');
1317 *dest++ = byte;
1318 len++;
1319 } else {
1320 *dest++ = *bp++;
1321 len++;
1322 }
1323 }
1324 }
1325
1326 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1327 return -1;
1328 while (*bp == ' ') bp++;
1329 *bpp = bp;
1330 *dest = '\0';
1331 return len;
1332}
1333EXPORT_SYMBOL_GPL(qword_get);
1334
1335
1336/*
1337 * support /proc/net/rpc/$CACHENAME/content
1338 * as a seqfile.
1339 * We call ->cache_show passing NULL for the item to
1340 * get a header, then pass each real item in the cache
1341 */
1342
1343static void *__cache_seq_start(struct seq_file *m, loff_t *pos)
1344{
1345 loff_t n = *pos;
1346 unsigned int hash, entry;
1347 struct cache_head *ch;
1348 struct cache_detail *cd = m->private;
1349
1350 if (!n--)
1351 return SEQ_START_TOKEN;
1352 hash = n >> 32;
1353 entry = n & ((1LL<<32) - 1);
1354
1355 hlist_for_each_entry_rcu(ch, &cd->hash_table[hash], cache_list)
1356 if (!entry--)
1357 return ch;
1358 n &= ~((1LL<<32) - 1);
1359 do {
1360 hash++;
1361 n += 1LL<<32;
1362 } while(hash < cd->hash_size &&
1363 hlist_empty(&cd->hash_table[hash]));
1364 if (hash >= cd->hash_size)
1365 return NULL;
1366 *pos = n+1;
1367 return hlist_entry_safe(rcu_dereference_raw(
1368 hlist_first_rcu(&cd->hash_table[hash])),
1369 struct cache_head, cache_list);
1370}
1371
1372static void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos)
1373{
1374 struct cache_head *ch = p;
1375 int hash = (*pos >> 32);
1376 struct cache_detail *cd = m->private;
1377
1378 if (p == SEQ_START_TOKEN)
1379 hash = 0;
1380 else if (ch->cache_list.next == NULL) {
1381 hash++;
1382 *pos += 1LL<<32;
1383 } else {
1384 ++*pos;
1385 return hlist_entry_safe(rcu_dereference_raw(
1386 hlist_next_rcu(&ch->cache_list)),
1387 struct cache_head, cache_list);
1388 }
1389 *pos &= ~((1LL<<32) - 1);
1390 while (hash < cd->hash_size &&
1391 hlist_empty(&cd->hash_table[hash])) {
1392 hash++;
1393 *pos += 1LL<<32;
1394 }
1395 if (hash >= cd->hash_size)
1396 return NULL;
1397 ++*pos;
1398 return hlist_entry_safe(rcu_dereference_raw(
1399 hlist_first_rcu(&cd->hash_table[hash])),
1400 struct cache_head, cache_list);
1401}
1402
1403void *cache_seq_start_rcu(struct seq_file *m, loff_t *pos)
1404 __acquires(RCU)
1405{
1406 rcu_read_lock();
1407 return __cache_seq_start(m, pos);
1408}
1409EXPORT_SYMBOL_GPL(cache_seq_start_rcu);
1410
1411void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos)
1412{
1413 return cache_seq_next(file, p, pos);
1414}
1415EXPORT_SYMBOL_GPL(cache_seq_next_rcu);
1416
1417void cache_seq_stop_rcu(struct seq_file *m, void *p)
1418 __releases(RCU)
1419{
1420 rcu_read_unlock();
1421}
1422EXPORT_SYMBOL_GPL(cache_seq_stop_rcu);
1423
1424static int c_show(struct seq_file *m, void *p)
1425{
1426 struct cache_head *cp = p;
1427 struct cache_detail *cd = m->private;
1428
1429 if (p == SEQ_START_TOKEN)
1430 return cd->cache_show(m, cd, NULL);
1431
1432 ifdebug(CACHE)
1433 seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
1434 convert_to_wallclock(cp->expiry_time),
1435 kref_read(&cp->ref), cp->flags);
1436 cache_get(cp);
1437 if (cache_check(cd, cp, NULL))
1438 /* cache_check does a cache_put on failure */
1439 seq_printf(m, "# ");
1440 else {
1441 if (cache_is_expired(cd, cp))
1442 seq_printf(m, "# ");
1443 cache_put(cp, cd);
1444 }
1445
1446 return cd->cache_show(m, cd, cp);
1447}
1448
1449static const struct seq_operations cache_content_op = {
1450 .start = cache_seq_start_rcu,
1451 .next = cache_seq_next_rcu,
1452 .stop = cache_seq_stop_rcu,
1453 .show = c_show,
1454};
1455
1456static int content_open(struct inode *inode, struct file *file,
1457 struct cache_detail *cd)
1458{
1459 struct seq_file *seq;
1460 int err;
1461
1462 if (!cd || !try_module_get(cd->owner))
1463 return -EACCES;
1464
1465 err = seq_open(file, &cache_content_op);
1466 if (err) {
1467 module_put(cd->owner);
1468 return err;
1469 }
1470
1471 seq = file->private_data;
1472 seq->private = cd;
1473 return 0;
1474}
1475
1476static int content_release(struct inode *inode, struct file *file,
1477 struct cache_detail *cd)
1478{
1479 int ret = seq_release(inode, file);
1480 module_put(cd->owner);
1481 return ret;
1482}
1483
1484static int open_flush(struct inode *inode, struct file *file,
1485 struct cache_detail *cd)
1486{
1487 if (!cd || !try_module_get(cd->owner))
1488 return -EACCES;
1489 return nonseekable_open(inode, file);
1490}
1491
1492static int release_flush(struct inode *inode, struct file *file,
1493 struct cache_detail *cd)
1494{
1495 module_put(cd->owner);
1496 return 0;
1497}
1498
1499static ssize_t read_flush(struct file *file, char __user *buf,
1500 size_t count, loff_t *ppos,
1501 struct cache_detail *cd)
1502{
1503 char tbuf[22];
1504 size_t len;
1505
1506 len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
1507 convert_to_wallclock(cd->flush_time));
1508 return simple_read_from_buffer(buf, count, ppos, tbuf, len);
1509}
1510
1511static ssize_t write_flush(struct file *file, const char __user *buf,
1512 size_t count, loff_t *ppos,
1513 struct cache_detail *cd)
1514{
1515 char tbuf[20];
1516 char *ep;
1517 time64_t now;
1518
1519 if (*ppos || count > sizeof(tbuf)-1)
1520 return -EINVAL;
1521 if (copy_from_user(tbuf, buf, count))
1522 return -EFAULT;
1523 tbuf[count] = 0;
1524 simple_strtoul(tbuf, &ep, 0);
1525 if (*ep && *ep != '\n')
1526 return -EINVAL;
1527 /* Note that while we check that 'buf' holds a valid number,
1528 * we always ignore the value and just flush everything.
1529 * Making use of the number leads to races.
1530 */
1531
1532 now = seconds_since_boot();
1533 /* Always flush everything, so behave like cache_purge()
1534 * Do this by advancing flush_time to the current time,
1535 * or by one second if it has already reached the current time.
1536 * Newly added cache entries will always have ->last_refresh greater
1537 * that ->flush_time, so they don't get flushed prematurely.
1538 */
1539
1540 if (cd->flush_time >= now)
1541 now = cd->flush_time + 1;
1542
1543 cd->flush_time = now;
1544 cd->nextcheck = now;
1545 cache_flush();
1546
1547 if (cd->flush)
1548 cd->flush();
1549
1550 *ppos += count;
1551 return count;
1552}
1553
1554static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1555 size_t count, loff_t *ppos)
1556{
1557 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1558
1559 return cache_read(filp, buf, count, ppos, cd);
1560}
1561
1562static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1563 size_t count, loff_t *ppos)
1564{
1565 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1566
1567 return cache_write(filp, buf, count, ppos, cd);
1568}
1569
1570static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)
1571{
1572 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1573
1574 return cache_poll(filp, wait, cd);
1575}
1576
1577static long cache_ioctl_procfs(struct file *filp,
1578 unsigned int cmd, unsigned long arg)
1579{
1580 struct inode *inode = file_inode(filp);
1581 struct cache_detail *cd = PDE_DATA(inode);
1582
1583 return cache_ioctl(inode, filp, cmd, arg, cd);
1584}
1585
1586static int cache_open_procfs(struct inode *inode, struct file *filp)
1587{
1588 struct cache_detail *cd = PDE_DATA(inode);
1589
1590 return cache_open(inode, filp, cd);
1591}
1592
1593static int cache_release_procfs(struct inode *inode, struct file *filp)
1594{
1595 struct cache_detail *cd = PDE_DATA(inode);
1596
1597 return cache_release(inode, filp, cd);
1598}
1599
1600static const struct proc_ops cache_channel_proc_ops = {
1601 .proc_lseek = no_llseek,
1602 .proc_read = cache_read_procfs,
1603 .proc_write = cache_write_procfs,
1604 .proc_poll = cache_poll_procfs,
1605 .proc_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1606 .proc_open = cache_open_procfs,
1607 .proc_release = cache_release_procfs,
1608};
1609
1610static int content_open_procfs(struct inode *inode, struct file *filp)
1611{
1612 struct cache_detail *cd = PDE_DATA(inode);
1613
1614 return content_open(inode, filp, cd);
1615}
1616
1617static int content_release_procfs(struct inode *inode, struct file *filp)
1618{
1619 struct cache_detail *cd = PDE_DATA(inode);
1620
1621 return content_release(inode, filp, cd);
1622}
1623
1624static const struct proc_ops content_proc_ops = {
1625 .proc_open = content_open_procfs,
1626 .proc_read = seq_read,
1627 .proc_lseek = seq_lseek,
1628 .proc_release = content_release_procfs,
1629};
1630
1631static int open_flush_procfs(struct inode *inode, struct file *filp)
1632{
1633 struct cache_detail *cd = PDE_DATA(inode);
1634
1635 return open_flush(inode, filp, cd);
1636}
1637
1638static int release_flush_procfs(struct inode *inode, struct file *filp)
1639{
1640 struct cache_detail *cd = PDE_DATA(inode);
1641
1642 return release_flush(inode, filp, cd);
1643}
1644
1645static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1646 size_t count, loff_t *ppos)
1647{
1648 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1649
1650 return read_flush(filp, buf, count, ppos, cd);
1651}
1652
1653static ssize_t write_flush_procfs(struct file *filp,
1654 const char __user *buf,
1655 size_t count, loff_t *ppos)
1656{
1657 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1658
1659 return write_flush(filp, buf, count, ppos, cd);
1660}
1661
1662static const struct proc_ops cache_flush_proc_ops = {
1663 .proc_open = open_flush_procfs,
1664 .proc_read = read_flush_procfs,
1665 .proc_write = write_flush_procfs,
1666 .proc_release = release_flush_procfs,
1667 .proc_lseek = no_llseek,
1668};
1669
1670static void remove_cache_proc_entries(struct cache_detail *cd)
1671{
1672 if (cd->procfs) {
1673 proc_remove(cd->procfs);
1674 cd->procfs = NULL;
1675 }
1676}
1677
1678#ifdef CONFIG_PROC_FS
1679static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1680{
1681 struct proc_dir_entry *p;
1682 struct sunrpc_net *sn;
1683
1684 sn = net_generic(net, sunrpc_net_id);
1685 cd->procfs = proc_mkdir(cd->name, sn->proc_net_rpc);
1686 if (cd->procfs == NULL)
1687 goto out_nomem;
1688
1689 p = proc_create_data("flush", S_IFREG | 0600,
1690 cd->procfs, &cache_flush_proc_ops, cd);
1691 if (p == NULL)
1692 goto out_nomem;
1693
1694 if (cd->cache_request || cd->cache_parse) {
1695 p = proc_create_data("channel", S_IFREG | 0600, cd->procfs,
1696 &cache_channel_proc_ops, cd);
1697 if (p == NULL)
1698 goto out_nomem;
1699 }
1700 if (cd->cache_show) {
1701 p = proc_create_data("content", S_IFREG | 0400, cd->procfs,
1702 &content_proc_ops, cd);
1703 if (p == NULL)
1704 goto out_nomem;
1705 }
1706 return 0;
1707out_nomem:
1708 remove_cache_proc_entries(cd);
1709 return -ENOMEM;
1710}
1711#else /* CONFIG_PROC_FS */
1712static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1713{
1714 return 0;
1715}
1716#endif
1717
1718void __init cache_initialize(void)
1719{
1720 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1721}
1722
1723int cache_register_net(struct cache_detail *cd, struct net *net)
1724{
1725 int ret;
1726
1727 sunrpc_init_cache_detail(cd);
1728 ret = create_cache_proc_entries(cd, net);
1729 if (ret)
1730 sunrpc_destroy_cache_detail(cd);
1731 return ret;
1732}
1733EXPORT_SYMBOL_GPL(cache_register_net);
1734
1735void cache_unregister_net(struct cache_detail *cd, struct net *net)
1736{
1737 remove_cache_proc_entries(cd);
1738 sunrpc_destroy_cache_detail(cd);
1739}
1740EXPORT_SYMBOL_GPL(cache_unregister_net);
1741
1742struct cache_detail *cache_create_net(const struct cache_detail *tmpl, struct net *net)
1743{
1744 struct cache_detail *cd;
1745 int i;
1746
1747 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1748 if (cd == NULL)
1749 return ERR_PTR(-ENOMEM);
1750
1751 cd->hash_table = kcalloc(cd->hash_size, sizeof(struct hlist_head),
1752 GFP_KERNEL);
1753 if (cd->hash_table == NULL) {
1754 kfree(cd);
1755 return ERR_PTR(-ENOMEM);
1756 }
1757
1758 for (i = 0; i < cd->hash_size; i++)
1759 INIT_HLIST_HEAD(&cd->hash_table[i]);
1760 cd->net = net;
1761 return cd;
1762}
1763EXPORT_SYMBOL_GPL(cache_create_net);
1764
1765void cache_destroy_net(struct cache_detail *cd, struct net *net)
1766{
1767 kfree(cd->hash_table);
1768 kfree(cd);
1769}
1770EXPORT_SYMBOL_GPL(cache_destroy_net);
1771
1772static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1773 size_t count, loff_t *ppos)
1774{
1775 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1776
1777 return cache_read(filp, buf, count, ppos, cd);
1778}
1779
1780static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1781 size_t count, loff_t *ppos)
1782{
1783 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1784
1785 return cache_write(filp, buf, count, ppos, cd);
1786}
1787
1788static __poll_t cache_poll_pipefs(struct file *filp, poll_table *wait)
1789{
1790 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1791
1792 return cache_poll(filp, wait, cd);
1793}
1794
1795static long cache_ioctl_pipefs(struct file *filp,
1796 unsigned int cmd, unsigned long arg)
1797{
1798 struct inode *inode = file_inode(filp);
1799 struct cache_detail *cd = RPC_I(inode)->private;
1800
1801 return cache_ioctl(inode, filp, cmd, arg, cd);
1802}
1803
1804static int cache_open_pipefs(struct inode *inode, struct file *filp)
1805{
1806 struct cache_detail *cd = RPC_I(inode)->private;
1807
1808 return cache_open(inode, filp, cd);
1809}
1810
1811static int cache_release_pipefs(struct inode *inode, struct file *filp)
1812{
1813 struct cache_detail *cd = RPC_I(inode)->private;
1814
1815 return cache_release(inode, filp, cd);
1816}
1817
1818const struct file_operations cache_file_operations_pipefs = {
1819 .owner = THIS_MODULE,
1820 .llseek = no_llseek,
1821 .read = cache_read_pipefs,
1822 .write = cache_write_pipefs,
1823 .poll = cache_poll_pipefs,
1824 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1825 .open = cache_open_pipefs,
1826 .release = cache_release_pipefs,
1827};
1828
1829static int content_open_pipefs(struct inode *inode, struct file *filp)
1830{
1831 struct cache_detail *cd = RPC_I(inode)->private;
1832
1833 return content_open(inode, filp, cd);
1834}
1835
1836static int content_release_pipefs(struct inode *inode, struct file *filp)
1837{
1838 struct cache_detail *cd = RPC_I(inode)->private;
1839
1840 return content_release(inode, filp, cd);
1841}
1842
1843const struct file_operations content_file_operations_pipefs = {
1844 .open = content_open_pipefs,
1845 .read = seq_read,
1846 .llseek = seq_lseek,
1847 .release = content_release_pipefs,
1848};
1849
1850static int open_flush_pipefs(struct inode *inode, struct file *filp)
1851{
1852 struct cache_detail *cd = RPC_I(inode)->private;
1853
1854 return open_flush(inode, filp, cd);
1855}
1856
1857static int release_flush_pipefs(struct inode *inode, struct file *filp)
1858{
1859 struct cache_detail *cd = RPC_I(inode)->private;
1860
1861 return release_flush(inode, filp, cd);
1862}
1863
1864static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1865 size_t count, loff_t *ppos)
1866{
1867 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1868
1869 return read_flush(filp, buf, count, ppos, cd);
1870}
1871
1872static ssize_t write_flush_pipefs(struct file *filp,
1873 const char __user *buf,
1874 size_t count, loff_t *ppos)
1875{
1876 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1877
1878 return write_flush(filp, buf, count, ppos, cd);
1879}
1880
1881const struct file_operations cache_flush_operations_pipefs = {
1882 .open = open_flush_pipefs,
1883 .read = read_flush_pipefs,
1884 .write = write_flush_pipefs,
1885 .release = release_flush_pipefs,
1886 .llseek = no_llseek,
1887};
1888
1889int sunrpc_cache_register_pipefs(struct dentry *parent,
1890 const char *name, umode_t umode,
1891 struct cache_detail *cd)
1892{
1893 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1894 if (IS_ERR(dir))
1895 return PTR_ERR(dir);
1896 cd->pipefs = dir;
1897 return 0;
1898}
1899EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1900
1901void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1902{
1903 if (cd->pipefs) {
1904 rpc_remove_cache_dir(cd->pipefs);
1905 cd->pipefs = NULL;
1906 }
1907}
1908EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1909
1910void sunrpc_cache_unhash(struct cache_detail *cd, struct cache_head *h)
1911{
1912 spin_lock(&cd->hash_lock);
1913 if (!hlist_unhashed(&h->cache_list)){
1914 sunrpc_begin_cache_remove_entry(h, cd);
1915 spin_unlock(&cd->hash_lock);
1916 sunrpc_end_cache_remove_entry(h, cd);
1917 } else
1918 spin_unlock(&cd->hash_lock);
1919}
1920EXPORT_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
53struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
54 struct cache_head *key, int hash)
55{
56 struct cache_head **head, **hp;
57 struct cache_head *new = NULL, *freeme = NULL;
58
59 head = &detail->hash_table[hash];
60
61 read_lock(&detail->hash_lock);
62
63 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
64 struct cache_head *tmp = *hp;
65 if (detail->match(tmp, key)) {
66 if (cache_is_expired(detail, tmp))
67 /* This entry is expired, we will discard it. */
68 break;
69 cache_get(tmp);
70 read_unlock(&detail->hash_lock);
71 return tmp;
72 }
73 }
74 read_unlock(&detail->hash_lock);
75 /* Didn't find anything, insert an empty entry */
76
77 new = detail->alloc();
78 if (!new)
79 return NULL;
80 /* must fully initialise 'new', else
81 * we might get lose if we need to
82 * cache_put it soon.
83 */
84 cache_init(new);
85 detail->init(new, key);
86
87 write_lock(&detail->hash_lock);
88
89 /* check if entry appeared while we slept */
90 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
91 struct cache_head *tmp = *hp;
92 if (detail->match(tmp, key)) {
93 if (cache_is_expired(detail, tmp)) {
94 *hp = tmp->next;
95 tmp->next = NULL;
96 detail->entries --;
97 freeme = tmp;
98 break;
99 }
100 cache_get(tmp);
101 write_unlock(&detail->hash_lock);
102 cache_put(new, detail);
103 return tmp;
104 }
105 }
106 new->next = *head;
107 *head = new;
108 detail->entries++;
109 cache_get(new);
110 write_unlock(&detail->hash_lock);
111
112 if (freeme)
113 cache_put(freeme, detail);
114 return new;
115}
116EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
117
118
119static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
120
121static void cache_fresh_locked(struct cache_head *head, time_t expiry)
122{
123 head->expiry_time = expiry;
124 head->last_refresh = seconds_since_boot();
125 smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
126 set_bit(CACHE_VALID, &head->flags);
127}
128
129static void cache_fresh_unlocked(struct cache_head *head,
130 struct cache_detail *detail)
131{
132 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
133 cache_revisit_request(head);
134 cache_dequeue(detail, head);
135 }
136}
137
138struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
139 struct cache_head *new, struct cache_head *old, int hash)
140{
141 /* The 'old' entry is to be replaced by 'new'.
142 * If 'old' is not VALID, we update it directly,
143 * otherwise we need to replace it
144 */
145 struct cache_head **head;
146 struct cache_head *tmp;
147
148 if (!test_bit(CACHE_VALID, &old->flags)) {
149 write_lock(&detail->hash_lock);
150 if (!test_bit(CACHE_VALID, &old->flags)) {
151 if (test_bit(CACHE_NEGATIVE, &new->flags))
152 set_bit(CACHE_NEGATIVE, &old->flags);
153 else
154 detail->update(old, new);
155 cache_fresh_locked(old, new->expiry_time);
156 write_unlock(&detail->hash_lock);
157 cache_fresh_unlocked(old, detail);
158 return old;
159 }
160 write_unlock(&detail->hash_lock);
161 }
162 /* We need to insert a new entry */
163 tmp = detail->alloc();
164 if (!tmp) {
165 cache_put(old, detail);
166 return NULL;
167 }
168 cache_init(tmp);
169 detail->init(tmp, old);
170 head = &detail->hash_table[hash];
171
172 write_lock(&detail->hash_lock);
173 if (test_bit(CACHE_NEGATIVE, &new->flags))
174 set_bit(CACHE_NEGATIVE, &tmp->flags);
175 else
176 detail->update(tmp, new);
177 tmp->next = *head;
178 *head = tmp;
179 detail->entries++;
180 cache_get(tmp);
181 cache_fresh_locked(tmp, new->expiry_time);
182 cache_fresh_locked(old, 0);
183 write_unlock(&detail->hash_lock);
184 cache_fresh_unlocked(tmp, detail);
185 cache_fresh_unlocked(old, detail);
186 cache_put(old, detail);
187 return tmp;
188}
189EXPORT_SYMBOL_GPL(sunrpc_cache_update);
190
191static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
192{
193 if (cd->cache_upcall)
194 return cd->cache_upcall(cd, h);
195 return sunrpc_cache_pipe_upcall(cd, h);
196}
197
198static inline int cache_is_valid(struct cache_head *h)
199{
200 if (!test_bit(CACHE_VALID, &h->flags))
201 return -EAGAIN;
202 else {
203 /* entry is valid */
204 if (test_bit(CACHE_NEGATIVE, &h->flags))
205 return -ENOENT;
206 else {
207 /*
208 * In combination with write barrier in
209 * sunrpc_cache_update, ensures that anyone
210 * using the cache entry after this sees the
211 * updated contents:
212 */
213 smp_rmb();
214 return 0;
215 }
216 }
217}
218
219static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
220{
221 int rv;
222
223 write_lock(&detail->hash_lock);
224 rv = cache_is_valid(h);
225 if (rv == -EAGAIN) {
226 set_bit(CACHE_NEGATIVE, &h->flags);
227 cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
228 rv = -ENOENT;
229 }
230 write_unlock(&detail->hash_lock);
231 cache_fresh_unlocked(h, detail);
232 return rv;
233}
234
235/*
236 * This is the generic cache management routine for all
237 * the authentication caches.
238 * It checks the currency of a cache item and will (later)
239 * initiate an upcall to fill it if needed.
240 *
241 *
242 * Returns 0 if the cache_head can be used, or cache_puts it and returns
243 * -EAGAIN if upcall is pending and request has been queued
244 * -ETIMEDOUT if upcall failed or request could not be queue or
245 * upcall completed but item is still invalid (implying that
246 * the cache item has been replaced with a newer one).
247 * -ENOENT if cache entry was negative
248 */
249int cache_check(struct cache_detail *detail,
250 struct cache_head *h, struct cache_req *rqstp)
251{
252 int rv;
253 long refresh_age, age;
254
255 /* First decide return status as best we can */
256 rv = cache_is_valid(h);
257
258 /* now see if we want to start an upcall */
259 refresh_age = (h->expiry_time - h->last_refresh);
260 age = seconds_since_boot() - h->last_refresh;
261
262 if (rqstp == NULL) {
263 if (rv == -EAGAIN)
264 rv = -ENOENT;
265 } else if (rv == -EAGAIN ||
266 (h->expiry_time != 0 && age > refresh_age/2)) {
267 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
268 refresh_age, age);
269 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
270 switch (cache_make_upcall(detail, h)) {
271 case -EINVAL:
272 rv = try_to_negate_entry(detail, h);
273 break;
274 case -EAGAIN:
275 cache_fresh_unlocked(h, detail);
276 break;
277 }
278 }
279 }
280
281 if (rv == -EAGAIN) {
282 if (!cache_defer_req(rqstp, h)) {
283 /*
284 * Request was not deferred; handle it as best
285 * we can ourselves:
286 */
287 rv = cache_is_valid(h);
288 if (rv == -EAGAIN)
289 rv = -ETIMEDOUT;
290 }
291 }
292 if (rv)
293 cache_put(h, detail);
294 return rv;
295}
296EXPORT_SYMBOL_GPL(cache_check);
297
298/*
299 * caches need to be periodically cleaned.
300 * For this we maintain a list of cache_detail and
301 * a current pointer into that list and into the table
302 * for that entry.
303 *
304 * Each time cache_clean is called it finds the next non-empty entry
305 * in the current table and walks the list in that entry
306 * looking for entries that can be removed.
307 *
308 * An entry gets removed if:
309 * - The expiry is before current time
310 * - The last_refresh time is before the flush_time for that cache
311 *
312 * later we might drop old entries with non-NEVER expiry if that table
313 * is getting 'full' for some definition of 'full'
314 *
315 * The question of "how often to scan a table" is an interesting one
316 * and is answered in part by the use of the "nextcheck" field in the
317 * cache_detail.
318 * When a scan of a table begins, the nextcheck field is set to a time
319 * that is well into the future.
320 * While scanning, if an expiry time is found that is earlier than the
321 * current nextcheck time, nextcheck is set to that expiry time.
322 * If the flush_time is ever set to a time earlier than the nextcheck
323 * time, the nextcheck time is then set to that flush_time.
324 *
325 * A table is then only scanned if the current time is at least
326 * the nextcheck time.
327 *
328 */
329
330static LIST_HEAD(cache_list);
331static DEFINE_SPINLOCK(cache_list_lock);
332static struct cache_detail *current_detail;
333static int current_index;
334
335static void do_cache_clean(struct work_struct *work);
336static struct delayed_work cache_cleaner;
337
338void sunrpc_init_cache_detail(struct cache_detail *cd)
339{
340 rwlock_init(&cd->hash_lock);
341 INIT_LIST_HEAD(&cd->queue);
342 spin_lock(&cache_list_lock);
343 cd->nextcheck = 0;
344 cd->entries = 0;
345 atomic_set(&cd->readers, 0);
346 cd->last_close = 0;
347 cd->last_warn = -1;
348 list_add(&cd->others, &cache_list);
349 spin_unlock(&cache_list_lock);
350
351 /* start the cleaning process */
352 schedule_delayed_work(&cache_cleaner, 0);
353}
354EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
355
356void sunrpc_destroy_cache_detail(struct cache_detail *cd)
357{
358 cache_purge(cd);
359 spin_lock(&cache_list_lock);
360 write_lock(&cd->hash_lock);
361 if (cd->entries || atomic_read(&cd->inuse)) {
362 write_unlock(&cd->hash_lock);
363 spin_unlock(&cache_list_lock);
364 goto out;
365 }
366 if (current_detail == cd)
367 current_detail = NULL;
368 list_del_init(&cd->others);
369 write_unlock(&cd->hash_lock);
370 spin_unlock(&cache_list_lock);
371 if (list_empty(&cache_list)) {
372 /* module must be being unloaded so its safe to kill the worker */
373 cancel_delayed_work_sync(&cache_cleaner);
374 }
375 return;
376out:
377 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
378}
379EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
380
381/* clean cache tries to find something to clean
382 * and cleans it.
383 * It returns 1 if it cleaned something,
384 * 0 if it didn't find anything this time
385 * -1 if it fell off the end of the list.
386 */
387static int cache_clean(void)
388{
389 int rv = 0;
390 struct list_head *next;
391
392 spin_lock(&cache_list_lock);
393
394 /* find a suitable table if we don't already have one */
395 while (current_detail == NULL ||
396 current_index >= current_detail->hash_size) {
397 if (current_detail)
398 next = current_detail->others.next;
399 else
400 next = cache_list.next;
401 if (next == &cache_list) {
402 current_detail = NULL;
403 spin_unlock(&cache_list_lock);
404 return -1;
405 }
406 current_detail = list_entry(next, struct cache_detail, others);
407 if (current_detail->nextcheck > seconds_since_boot())
408 current_index = current_detail->hash_size;
409 else {
410 current_index = 0;
411 current_detail->nextcheck = seconds_since_boot()+30*60;
412 }
413 }
414
415 /* find a non-empty bucket in the table */
416 while (current_detail &&
417 current_index < current_detail->hash_size &&
418 current_detail->hash_table[current_index] == NULL)
419 current_index++;
420
421 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
422
423 if (current_detail && current_index < current_detail->hash_size) {
424 struct cache_head *ch, **cp;
425 struct cache_detail *d;
426
427 write_lock(¤t_detail->hash_lock);
428
429 /* Ok, now to clean this strand */
430
431 cp = & current_detail->hash_table[current_index];
432 for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
433 if (current_detail->nextcheck > ch->expiry_time)
434 current_detail->nextcheck = ch->expiry_time+1;
435 if (!cache_is_expired(current_detail, ch))
436 continue;
437
438 *cp = ch->next;
439 ch->next = NULL;
440 current_detail->entries--;
441 rv = 1;
442 break;
443 }
444
445 write_unlock(¤t_detail->hash_lock);
446 d = current_detail;
447 if (!ch)
448 current_index ++;
449 spin_unlock(&cache_list_lock);
450 if (ch) {
451 set_bit(CACHE_CLEANED, &ch->flags);
452 cache_fresh_unlocked(ch, d);
453 cache_put(ch, d);
454 }
455 } else
456 spin_unlock(&cache_list_lock);
457
458 return rv;
459}
460
461/*
462 * We want to regularly clean the cache, so we need to schedule some work ...
463 */
464static void do_cache_clean(struct work_struct *work)
465{
466 int delay = 5;
467 if (cache_clean() == -1)
468 delay = round_jiffies_relative(30*HZ);
469
470 if (list_empty(&cache_list))
471 delay = 0;
472
473 if (delay)
474 schedule_delayed_work(&cache_cleaner, delay);
475}
476
477
478/*
479 * Clean all caches promptly. This just calls cache_clean
480 * repeatedly until we are sure that every cache has had a chance to
481 * be fully cleaned
482 */
483void cache_flush(void)
484{
485 while (cache_clean() != -1)
486 cond_resched();
487 while (cache_clean() != -1)
488 cond_resched();
489}
490EXPORT_SYMBOL_GPL(cache_flush);
491
492void cache_purge(struct cache_detail *detail)
493{
494 detail->flush_time = LONG_MAX;
495 detail->nextcheck = seconds_since_boot();
496 cache_flush();
497 detail->flush_time = 1;
498}
499EXPORT_SYMBOL_GPL(cache_purge);
500
501
502/*
503 * Deferral and Revisiting of Requests.
504 *
505 * If a cache lookup finds a pending entry, we
506 * need to defer the request and revisit it later.
507 * All deferred requests are stored in a hash table,
508 * indexed by "struct cache_head *".
509 * As it may be wasteful to store a whole request
510 * structure, we allow the request to provide a
511 * deferred form, which must contain a
512 * 'struct cache_deferred_req'
513 * This cache_deferred_req contains a method to allow
514 * it to be revisited when cache info is available
515 */
516
517#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
518#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
519
520#define DFR_MAX 300 /* ??? */
521
522static DEFINE_SPINLOCK(cache_defer_lock);
523static LIST_HEAD(cache_defer_list);
524static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
525static int cache_defer_cnt;
526
527static void __unhash_deferred_req(struct cache_deferred_req *dreq)
528{
529 hlist_del_init(&dreq->hash);
530 if (!list_empty(&dreq->recent)) {
531 list_del_init(&dreq->recent);
532 cache_defer_cnt--;
533 }
534}
535
536static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
537{
538 int hash = DFR_HASH(item);
539
540 INIT_LIST_HEAD(&dreq->recent);
541 hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
542}
543
544static void setup_deferral(struct cache_deferred_req *dreq,
545 struct cache_head *item,
546 int count_me)
547{
548
549 dreq->item = item;
550
551 spin_lock(&cache_defer_lock);
552
553 __hash_deferred_req(dreq, item);
554
555 if (count_me) {
556 cache_defer_cnt++;
557 list_add(&dreq->recent, &cache_defer_list);
558 }
559
560 spin_unlock(&cache_defer_lock);
561
562}
563
564struct thread_deferred_req {
565 struct cache_deferred_req handle;
566 struct completion completion;
567};
568
569static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
570{
571 struct thread_deferred_req *dr =
572 container_of(dreq, struct thread_deferred_req, handle);
573 complete(&dr->completion);
574}
575
576static void cache_wait_req(struct cache_req *req, struct cache_head *item)
577{
578 struct thread_deferred_req sleeper;
579 struct cache_deferred_req *dreq = &sleeper.handle;
580
581 sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
582 dreq->revisit = cache_restart_thread;
583
584 setup_deferral(dreq, item, 0);
585
586 if (!test_bit(CACHE_PENDING, &item->flags) ||
587 wait_for_completion_interruptible_timeout(
588 &sleeper.completion, req->thread_wait) <= 0) {
589 /* The completion wasn't completed, so we need
590 * to clean up
591 */
592 spin_lock(&cache_defer_lock);
593 if (!hlist_unhashed(&sleeper.handle.hash)) {
594 __unhash_deferred_req(&sleeper.handle);
595 spin_unlock(&cache_defer_lock);
596 } else {
597 /* cache_revisit_request already removed
598 * this from the hash table, but hasn't
599 * called ->revisit yet. It will very soon
600 * and we need to wait for it.
601 */
602 spin_unlock(&cache_defer_lock);
603 wait_for_completion(&sleeper.completion);
604 }
605 }
606}
607
608static void cache_limit_defers(void)
609{
610 /* Make sure we haven't exceed the limit of allowed deferred
611 * requests.
612 */
613 struct cache_deferred_req *discard = NULL;
614
615 if (cache_defer_cnt <= DFR_MAX)
616 return;
617
618 spin_lock(&cache_defer_lock);
619
620 /* Consider removing either the first or the last */
621 if (cache_defer_cnt > DFR_MAX) {
622 if (prandom_u32() & 1)
623 discard = list_entry(cache_defer_list.next,
624 struct cache_deferred_req, recent);
625 else
626 discard = list_entry(cache_defer_list.prev,
627 struct cache_deferred_req, recent);
628 __unhash_deferred_req(discard);
629 }
630 spin_unlock(&cache_defer_lock);
631 if (discard)
632 discard->revisit(discard, 1);
633}
634
635/* Return true if and only if a deferred request is queued. */
636static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
637{
638 struct cache_deferred_req *dreq;
639
640 if (req->thread_wait) {
641 cache_wait_req(req, item);
642 if (!test_bit(CACHE_PENDING, &item->flags))
643 return false;
644 }
645 dreq = req->defer(req);
646 if (dreq == NULL)
647 return false;
648 setup_deferral(dreq, item, 1);
649 if (!test_bit(CACHE_PENDING, &item->flags))
650 /* Bit could have been cleared before we managed to
651 * set up the deferral, so need to revisit just in case
652 */
653 cache_revisit_request(item);
654
655 cache_limit_defers();
656 return true;
657}
658
659static void cache_revisit_request(struct cache_head *item)
660{
661 struct cache_deferred_req *dreq;
662 struct list_head pending;
663 struct hlist_node *tmp;
664 int hash = DFR_HASH(item);
665
666 INIT_LIST_HEAD(&pending);
667 spin_lock(&cache_defer_lock);
668
669 hlist_for_each_entry_safe(dreq, tmp, &cache_defer_hash[hash], hash)
670 if (dreq->item == item) {
671 __unhash_deferred_req(dreq);
672 list_add(&dreq->recent, &pending);
673 }
674
675 spin_unlock(&cache_defer_lock);
676
677 while (!list_empty(&pending)) {
678 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
679 list_del_init(&dreq->recent);
680 dreq->revisit(dreq, 0);
681 }
682}
683
684void cache_clean_deferred(void *owner)
685{
686 struct cache_deferred_req *dreq, *tmp;
687 struct list_head pending;
688
689
690 INIT_LIST_HEAD(&pending);
691 spin_lock(&cache_defer_lock);
692
693 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
694 if (dreq->owner == owner) {
695 __unhash_deferred_req(dreq);
696 list_add(&dreq->recent, &pending);
697 }
698 }
699 spin_unlock(&cache_defer_lock);
700
701 while (!list_empty(&pending)) {
702 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
703 list_del_init(&dreq->recent);
704 dreq->revisit(dreq, 1);
705 }
706}
707
708/*
709 * communicate with user-space
710 *
711 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
712 * On read, you get a full request, or block.
713 * On write, an update request is processed.
714 * Poll works if anything to read, and always allows write.
715 *
716 * Implemented by linked list of requests. Each open file has
717 * a ->private that also exists in this list. New requests are added
718 * to the end and may wakeup and preceding readers.
719 * New readers are added to the head. If, on read, an item is found with
720 * CACHE_UPCALLING clear, we free it from the list.
721 *
722 */
723
724static DEFINE_SPINLOCK(queue_lock);
725static DEFINE_MUTEX(queue_io_mutex);
726
727struct cache_queue {
728 struct list_head list;
729 int reader; /* if 0, then request */
730};
731struct cache_request {
732 struct cache_queue q;
733 struct cache_head *item;
734 char * buf;
735 int len;
736 int readers;
737};
738struct cache_reader {
739 struct cache_queue q;
740 int offset; /* if non-0, we have a refcnt on next request */
741};
742
743static int cache_request(struct cache_detail *detail,
744 struct cache_request *crq)
745{
746 char *bp = crq->buf;
747 int len = PAGE_SIZE;
748
749 detail->cache_request(detail, crq->item, &bp, &len);
750 if (len < 0)
751 return -EAGAIN;
752 return PAGE_SIZE - len;
753}
754
755static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
756 loff_t *ppos, struct cache_detail *cd)
757{
758 struct cache_reader *rp = filp->private_data;
759 struct cache_request *rq;
760 struct inode *inode = file_inode(filp);
761 int err;
762
763 if (count == 0)
764 return 0;
765
766 mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
767 * readers on this file */
768 again:
769 spin_lock(&queue_lock);
770 /* need to find next request */
771 while (rp->q.list.next != &cd->queue &&
772 list_entry(rp->q.list.next, struct cache_queue, list)
773 ->reader) {
774 struct list_head *next = rp->q.list.next;
775 list_move(&rp->q.list, next);
776 }
777 if (rp->q.list.next == &cd->queue) {
778 spin_unlock(&queue_lock);
779 mutex_unlock(&inode->i_mutex);
780 WARN_ON_ONCE(rp->offset);
781 return 0;
782 }
783 rq = container_of(rp->q.list.next, struct cache_request, q.list);
784 WARN_ON_ONCE(rq->q.reader);
785 if (rp->offset == 0)
786 rq->readers++;
787 spin_unlock(&queue_lock);
788
789 if (rq->len == 0) {
790 err = cache_request(cd, rq);
791 if (err < 0)
792 goto out;
793 rq->len = err;
794 }
795
796 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
797 err = -EAGAIN;
798 spin_lock(&queue_lock);
799 list_move(&rp->q.list, &rq->q.list);
800 spin_unlock(&queue_lock);
801 } else {
802 if (rp->offset + count > rq->len)
803 count = rq->len - rp->offset;
804 err = -EFAULT;
805 if (copy_to_user(buf, rq->buf + rp->offset, count))
806 goto out;
807 rp->offset += count;
808 if (rp->offset >= rq->len) {
809 rp->offset = 0;
810 spin_lock(&queue_lock);
811 list_move(&rp->q.list, &rq->q.list);
812 spin_unlock(&queue_lock);
813 }
814 err = 0;
815 }
816 out:
817 if (rp->offset == 0) {
818 /* need to release rq */
819 spin_lock(&queue_lock);
820 rq->readers--;
821 if (rq->readers == 0 &&
822 !test_bit(CACHE_PENDING, &rq->item->flags)) {
823 list_del(&rq->q.list);
824 spin_unlock(&queue_lock);
825 cache_put(rq->item, cd);
826 kfree(rq->buf);
827 kfree(rq);
828 } else
829 spin_unlock(&queue_lock);
830 }
831 if (err == -EAGAIN)
832 goto again;
833 mutex_unlock(&inode->i_mutex);
834 return err ? err : count;
835}
836
837static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
838 size_t count, struct cache_detail *cd)
839{
840 ssize_t ret;
841
842 if (count == 0)
843 return -EINVAL;
844 if (copy_from_user(kaddr, buf, count))
845 return -EFAULT;
846 kaddr[count] = '\0';
847 ret = cd->cache_parse(cd, kaddr, count);
848 if (!ret)
849 ret = count;
850 return ret;
851}
852
853static ssize_t cache_slow_downcall(const char __user *buf,
854 size_t count, struct cache_detail *cd)
855{
856 static char write_buf[8192]; /* protected by queue_io_mutex */
857 ssize_t ret = -EINVAL;
858
859 if (count >= sizeof(write_buf))
860 goto out;
861 mutex_lock(&queue_io_mutex);
862 ret = cache_do_downcall(write_buf, buf, count, cd);
863 mutex_unlock(&queue_io_mutex);
864out:
865 return ret;
866}
867
868static ssize_t cache_downcall(struct address_space *mapping,
869 const char __user *buf,
870 size_t count, struct cache_detail *cd)
871{
872 struct page *page;
873 char *kaddr;
874 ssize_t ret = -ENOMEM;
875
876 if (count >= PAGE_CACHE_SIZE)
877 goto out_slow;
878
879 page = find_or_create_page(mapping, 0, GFP_KERNEL);
880 if (!page)
881 goto out_slow;
882
883 kaddr = kmap(page);
884 ret = cache_do_downcall(kaddr, buf, count, cd);
885 kunmap(page);
886 unlock_page(page);
887 page_cache_release(page);
888 return ret;
889out_slow:
890 return cache_slow_downcall(buf, count, cd);
891}
892
893static ssize_t cache_write(struct file *filp, const char __user *buf,
894 size_t count, loff_t *ppos,
895 struct cache_detail *cd)
896{
897 struct address_space *mapping = filp->f_mapping;
898 struct inode *inode = file_inode(filp);
899 ssize_t ret = -EINVAL;
900
901 if (!cd->cache_parse)
902 goto out;
903
904 mutex_lock(&inode->i_mutex);
905 ret = cache_downcall(mapping, buf, count, cd);
906 mutex_unlock(&inode->i_mutex);
907out:
908 return ret;
909}
910
911static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
912
913static unsigned int cache_poll(struct file *filp, poll_table *wait,
914 struct cache_detail *cd)
915{
916 unsigned int mask;
917 struct cache_reader *rp = filp->private_data;
918 struct cache_queue *cq;
919
920 poll_wait(filp, &queue_wait, wait);
921
922 /* alway allow write */
923 mask = POLL_OUT | POLLWRNORM;
924
925 if (!rp)
926 return mask;
927
928 spin_lock(&queue_lock);
929
930 for (cq= &rp->q; &cq->list != &cd->queue;
931 cq = list_entry(cq->list.next, struct cache_queue, list))
932 if (!cq->reader) {
933 mask |= POLLIN | POLLRDNORM;
934 break;
935 }
936 spin_unlock(&queue_lock);
937 return mask;
938}
939
940static int cache_ioctl(struct inode *ino, struct file *filp,
941 unsigned int cmd, unsigned long arg,
942 struct cache_detail *cd)
943{
944 int len = 0;
945 struct cache_reader *rp = filp->private_data;
946 struct cache_queue *cq;
947
948 if (cmd != FIONREAD || !rp)
949 return -EINVAL;
950
951 spin_lock(&queue_lock);
952
953 /* only find the length remaining in current request,
954 * or the length of the next request
955 */
956 for (cq= &rp->q; &cq->list != &cd->queue;
957 cq = list_entry(cq->list.next, struct cache_queue, list))
958 if (!cq->reader) {
959 struct cache_request *cr =
960 container_of(cq, struct cache_request, q);
961 len = cr->len - rp->offset;
962 break;
963 }
964 spin_unlock(&queue_lock);
965
966 return put_user(len, (int __user *)arg);
967}
968
969static int cache_open(struct inode *inode, struct file *filp,
970 struct cache_detail *cd)
971{
972 struct cache_reader *rp = NULL;
973
974 if (!cd || !try_module_get(cd->owner))
975 return -EACCES;
976 nonseekable_open(inode, filp);
977 if (filp->f_mode & FMODE_READ) {
978 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
979 if (!rp) {
980 module_put(cd->owner);
981 return -ENOMEM;
982 }
983 rp->offset = 0;
984 rp->q.reader = 1;
985 atomic_inc(&cd->readers);
986 spin_lock(&queue_lock);
987 list_add(&rp->q.list, &cd->queue);
988 spin_unlock(&queue_lock);
989 }
990 filp->private_data = rp;
991 return 0;
992}
993
994static int cache_release(struct inode *inode, struct file *filp,
995 struct cache_detail *cd)
996{
997 struct cache_reader *rp = filp->private_data;
998
999 if (rp) {
1000 spin_lock(&queue_lock);
1001 if (rp->offset) {
1002 struct cache_queue *cq;
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 container_of(cq, struct cache_request, q)
1007 ->readers--;
1008 break;
1009 }
1010 rp->offset = 0;
1011 }
1012 list_del(&rp->q.list);
1013 spin_unlock(&queue_lock);
1014
1015 filp->private_data = NULL;
1016 kfree(rp);
1017
1018 cd->last_close = seconds_since_boot();
1019 atomic_dec(&cd->readers);
1020 }
1021 module_put(cd->owner);
1022 return 0;
1023}
1024
1025
1026
1027static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1028{
1029 struct cache_queue *cq, *tmp;
1030 struct cache_request *cr;
1031 struct list_head dequeued;
1032
1033 INIT_LIST_HEAD(&dequeued);
1034 spin_lock(&queue_lock);
1035 list_for_each_entry_safe(cq, tmp, &detail->queue, list)
1036 if (!cq->reader) {
1037 cr = container_of(cq, struct cache_request, q);
1038 if (cr->item != ch)
1039 continue;
1040 if (test_bit(CACHE_PENDING, &ch->flags))
1041 /* Lost a race and it is pending again */
1042 break;
1043 if (cr->readers != 0)
1044 continue;
1045 list_move(&cr->q.list, &dequeued);
1046 }
1047 spin_unlock(&queue_lock);
1048 while (!list_empty(&dequeued)) {
1049 cr = list_entry(dequeued.next, struct cache_request, q.list);
1050 list_del(&cr->q.list);
1051 cache_put(cr->item, detail);
1052 kfree(cr->buf);
1053 kfree(cr);
1054 }
1055}
1056
1057/*
1058 * Support routines for text-based upcalls.
1059 * Fields are separated by spaces.
1060 * Fields are either mangled to quote space tab newline slosh with slosh
1061 * or a hexified with a leading \x
1062 * Record is terminated with newline.
1063 *
1064 */
1065
1066void qword_add(char **bpp, int *lp, char *str)
1067{
1068 char *bp = *bpp;
1069 int len = *lp;
1070 char c;
1071
1072 if (len < 0) return;
1073
1074 while ((c=*str++) && len)
1075 switch(c) {
1076 case ' ':
1077 case '\t':
1078 case '\n':
1079 case '\\':
1080 if (len >= 4) {
1081 *bp++ = '\\';
1082 *bp++ = '0' + ((c & 0300)>>6);
1083 *bp++ = '0' + ((c & 0070)>>3);
1084 *bp++ = '0' + ((c & 0007)>>0);
1085 }
1086 len -= 4;
1087 break;
1088 default:
1089 *bp++ = c;
1090 len--;
1091 }
1092 if (c || len <1) len = -1;
1093 else {
1094 *bp++ = ' ';
1095 len--;
1096 }
1097 *bpp = bp;
1098 *lp = len;
1099}
1100EXPORT_SYMBOL_GPL(qword_add);
1101
1102void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1103{
1104 char *bp = *bpp;
1105 int len = *lp;
1106
1107 if (len < 0) return;
1108
1109 if (len > 2) {
1110 *bp++ = '\\';
1111 *bp++ = 'x';
1112 len -= 2;
1113 while (blen && len >= 2) {
1114 bp = hex_byte_pack(bp, *buf++);
1115 len -= 2;
1116 blen--;
1117 }
1118 }
1119 if (blen || len<1) len = -1;
1120 else {
1121 *bp++ = ' ';
1122 len--;
1123 }
1124 *bpp = bp;
1125 *lp = len;
1126}
1127EXPORT_SYMBOL_GPL(qword_addhex);
1128
1129static void warn_no_listener(struct cache_detail *detail)
1130{
1131 if (detail->last_warn != detail->last_close) {
1132 detail->last_warn = detail->last_close;
1133 if (detail->warn_no_listener)
1134 detail->warn_no_listener(detail, detail->last_close != 0);
1135 }
1136}
1137
1138static bool cache_listeners_exist(struct cache_detail *detail)
1139{
1140 if (atomic_read(&detail->readers))
1141 return true;
1142 if (detail->last_close == 0)
1143 /* This cache was never opened */
1144 return false;
1145 if (detail->last_close < seconds_since_boot() - 30)
1146 /*
1147 * We allow for the possibility that someone might
1148 * restart a userspace daemon without restarting the
1149 * server; but after 30 seconds, we give up.
1150 */
1151 return false;
1152 return true;
1153}
1154
1155/*
1156 * register an upcall request to user-space and queue it up for read() by the
1157 * upcall daemon.
1158 *
1159 * Each request is at most one page long.
1160 */
1161int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
1162{
1163
1164 char *buf;
1165 struct cache_request *crq;
1166 int ret = 0;
1167
1168 if (!detail->cache_request)
1169 return -EINVAL;
1170
1171 if (!cache_listeners_exist(detail)) {
1172 warn_no_listener(detail);
1173 return -EINVAL;
1174 }
1175 if (test_bit(CACHE_CLEANED, &h->flags))
1176 /* Too late to make an upcall */
1177 return -EAGAIN;
1178
1179 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1180 if (!buf)
1181 return -EAGAIN;
1182
1183 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1184 if (!crq) {
1185 kfree(buf);
1186 return -EAGAIN;
1187 }
1188
1189 crq->q.reader = 0;
1190 crq->item = cache_get(h);
1191 crq->buf = buf;
1192 crq->len = 0;
1193 crq->readers = 0;
1194 spin_lock(&queue_lock);
1195 if (test_bit(CACHE_PENDING, &h->flags))
1196 list_add_tail(&crq->q.list, &detail->queue);
1197 else
1198 /* Lost a race, no longer PENDING, so don't enqueue */
1199 ret = -EAGAIN;
1200 spin_unlock(&queue_lock);
1201 wake_up(&queue_wait);
1202 if (ret == -EAGAIN) {
1203 kfree(buf);
1204 kfree(crq);
1205 }
1206 return ret;
1207}
1208EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1209
1210/*
1211 * parse a message from user-space and pass it
1212 * to an appropriate cache
1213 * Messages are, like requests, separated into fields by
1214 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1215 *
1216 * Message is
1217 * reply cachename expiry key ... content....
1218 *
1219 * key and content are both parsed by cache
1220 */
1221
1222int qword_get(char **bpp, char *dest, int bufsize)
1223{
1224 /* return bytes copied, or -1 on error */
1225 char *bp = *bpp;
1226 int len = 0;
1227
1228 while (*bp == ' ') bp++;
1229
1230 if (bp[0] == '\\' && bp[1] == 'x') {
1231 /* HEX STRING */
1232 bp += 2;
1233 while (len < bufsize) {
1234 int h, l;
1235
1236 h = hex_to_bin(bp[0]);
1237 if (h < 0)
1238 break;
1239
1240 l = hex_to_bin(bp[1]);
1241 if (l < 0)
1242 break;
1243
1244 *dest++ = (h << 4) | l;
1245 bp += 2;
1246 len++;
1247 }
1248 } else {
1249 /* text with \nnn octal quoting */
1250 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1251 if (*bp == '\\' &&
1252 isodigit(bp[1]) && (bp[1] <= '3') &&
1253 isodigit(bp[2]) &&
1254 isodigit(bp[3])) {
1255 int byte = (*++bp -'0');
1256 bp++;
1257 byte = (byte << 3) | (*bp++ - '0');
1258 byte = (byte << 3) | (*bp++ - '0');
1259 *dest++ = byte;
1260 len++;
1261 } else {
1262 *dest++ = *bp++;
1263 len++;
1264 }
1265 }
1266 }
1267
1268 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1269 return -1;
1270 while (*bp == ' ') bp++;
1271 *bpp = bp;
1272 *dest = '\0';
1273 return len;
1274}
1275EXPORT_SYMBOL_GPL(qword_get);
1276
1277
1278/*
1279 * support /proc/sunrpc/cache/$CACHENAME/content
1280 * as a seqfile.
1281 * We call ->cache_show passing NULL for the item to
1282 * get a header, then pass each real item in the cache
1283 */
1284
1285struct handle {
1286 struct cache_detail *cd;
1287};
1288
1289static void *c_start(struct seq_file *m, loff_t *pos)
1290 __acquires(cd->hash_lock)
1291{
1292 loff_t n = *pos;
1293 unsigned int hash, entry;
1294 struct cache_head *ch;
1295 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1296
1297
1298 read_lock(&cd->hash_lock);
1299 if (!n--)
1300 return SEQ_START_TOKEN;
1301 hash = n >> 32;
1302 entry = n & ((1LL<<32) - 1);
1303
1304 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1305 if (!entry--)
1306 return ch;
1307 n &= ~((1LL<<32) - 1);
1308 do {
1309 hash++;
1310 n += 1LL<<32;
1311 } while(hash < cd->hash_size &&
1312 cd->hash_table[hash]==NULL);
1313 if (hash >= cd->hash_size)
1314 return NULL;
1315 *pos = n+1;
1316 return cd->hash_table[hash];
1317}
1318
1319static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1320{
1321 struct cache_head *ch = p;
1322 int hash = (*pos >> 32);
1323 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1324
1325 if (p == SEQ_START_TOKEN)
1326 hash = 0;
1327 else if (ch->next == NULL) {
1328 hash++;
1329 *pos += 1LL<<32;
1330 } else {
1331 ++*pos;
1332 return ch->next;
1333 }
1334 *pos &= ~((1LL<<32) - 1);
1335 while (hash < cd->hash_size &&
1336 cd->hash_table[hash] == NULL) {
1337 hash++;
1338 *pos += 1LL<<32;
1339 }
1340 if (hash >= cd->hash_size)
1341 return NULL;
1342 ++*pos;
1343 return cd->hash_table[hash];
1344}
1345
1346static void c_stop(struct seq_file *m, void *p)
1347 __releases(cd->hash_lock)
1348{
1349 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1350 read_unlock(&cd->hash_lock);
1351}
1352
1353static int c_show(struct seq_file *m, void *p)
1354{
1355 struct cache_head *cp = p;
1356 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1357
1358 if (p == SEQ_START_TOKEN)
1359 return cd->cache_show(m, cd, NULL);
1360
1361 ifdebug(CACHE)
1362 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1363 convert_to_wallclock(cp->expiry_time),
1364 atomic_read(&cp->ref.refcount), cp->flags);
1365 cache_get(cp);
1366 if (cache_check(cd, cp, NULL))
1367 /* cache_check does a cache_put on failure */
1368 seq_printf(m, "# ");
1369 else {
1370 if (cache_is_expired(cd, cp))
1371 seq_printf(m, "# ");
1372 cache_put(cp, cd);
1373 }
1374
1375 return cd->cache_show(m, cd, cp);
1376}
1377
1378static const struct seq_operations cache_content_op = {
1379 .start = c_start,
1380 .next = c_next,
1381 .stop = c_stop,
1382 .show = c_show,
1383};
1384
1385static int content_open(struct inode *inode, struct file *file,
1386 struct cache_detail *cd)
1387{
1388 struct handle *han;
1389
1390 if (!cd || !try_module_get(cd->owner))
1391 return -EACCES;
1392 han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1393 if (han == NULL) {
1394 module_put(cd->owner);
1395 return -ENOMEM;
1396 }
1397
1398 han->cd = cd;
1399 return 0;
1400}
1401
1402static int content_release(struct inode *inode, struct file *file,
1403 struct cache_detail *cd)
1404{
1405 int ret = seq_release_private(inode, file);
1406 module_put(cd->owner);
1407 return ret;
1408}
1409
1410static int open_flush(struct inode *inode, struct file *file,
1411 struct cache_detail *cd)
1412{
1413 if (!cd || !try_module_get(cd->owner))
1414 return -EACCES;
1415 return nonseekable_open(inode, file);
1416}
1417
1418static int release_flush(struct inode *inode, struct file *file,
1419 struct cache_detail *cd)
1420{
1421 module_put(cd->owner);
1422 return 0;
1423}
1424
1425static ssize_t read_flush(struct file *file, char __user *buf,
1426 size_t count, loff_t *ppos,
1427 struct cache_detail *cd)
1428{
1429 char tbuf[22];
1430 unsigned long p = *ppos;
1431 size_t len;
1432
1433 snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1434 len = strlen(tbuf);
1435 if (p >= len)
1436 return 0;
1437 len -= p;
1438 if (len > count)
1439 len = count;
1440 if (copy_to_user(buf, (void*)(tbuf+p), len))
1441 return -EFAULT;
1442 *ppos += len;
1443 return len;
1444}
1445
1446static ssize_t write_flush(struct file *file, const char __user *buf,
1447 size_t count, loff_t *ppos,
1448 struct cache_detail *cd)
1449{
1450 char tbuf[20];
1451 char *bp, *ep;
1452
1453 if (*ppos || count > sizeof(tbuf)-1)
1454 return -EINVAL;
1455 if (copy_from_user(tbuf, buf, count))
1456 return -EFAULT;
1457 tbuf[count] = 0;
1458 simple_strtoul(tbuf, &ep, 0);
1459 if (*ep && *ep != '\n')
1460 return -EINVAL;
1461
1462 bp = tbuf;
1463 cd->flush_time = get_expiry(&bp);
1464 cd->nextcheck = seconds_since_boot();
1465 cache_flush();
1466
1467 *ppos += count;
1468 return count;
1469}
1470
1471static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1472 size_t count, loff_t *ppos)
1473{
1474 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1475
1476 return cache_read(filp, buf, count, ppos, cd);
1477}
1478
1479static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1480 size_t count, loff_t *ppos)
1481{
1482 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1483
1484 return cache_write(filp, buf, count, ppos, cd);
1485}
1486
1487static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1488{
1489 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1490
1491 return cache_poll(filp, wait, cd);
1492}
1493
1494static long cache_ioctl_procfs(struct file *filp,
1495 unsigned int cmd, unsigned long arg)
1496{
1497 struct inode *inode = file_inode(filp);
1498 struct cache_detail *cd = PDE_DATA(inode);
1499
1500 return cache_ioctl(inode, filp, cmd, arg, cd);
1501}
1502
1503static int cache_open_procfs(struct inode *inode, struct file *filp)
1504{
1505 struct cache_detail *cd = PDE_DATA(inode);
1506
1507 return cache_open(inode, filp, cd);
1508}
1509
1510static int cache_release_procfs(struct inode *inode, struct file *filp)
1511{
1512 struct cache_detail *cd = PDE_DATA(inode);
1513
1514 return cache_release(inode, filp, cd);
1515}
1516
1517static const struct file_operations cache_file_operations_procfs = {
1518 .owner = THIS_MODULE,
1519 .llseek = no_llseek,
1520 .read = cache_read_procfs,
1521 .write = cache_write_procfs,
1522 .poll = cache_poll_procfs,
1523 .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1524 .open = cache_open_procfs,
1525 .release = cache_release_procfs,
1526};
1527
1528static int content_open_procfs(struct inode *inode, struct file *filp)
1529{
1530 struct cache_detail *cd = PDE_DATA(inode);
1531
1532 return content_open(inode, filp, cd);
1533}
1534
1535static int content_release_procfs(struct inode *inode, struct file *filp)
1536{
1537 struct cache_detail *cd = PDE_DATA(inode);
1538
1539 return content_release(inode, filp, cd);
1540}
1541
1542static const struct file_operations content_file_operations_procfs = {
1543 .open = content_open_procfs,
1544 .read = seq_read,
1545 .llseek = seq_lseek,
1546 .release = content_release_procfs,
1547};
1548
1549static int open_flush_procfs(struct inode *inode, struct file *filp)
1550{
1551 struct cache_detail *cd = PDE_DATA(inode);
1552
1553 return open_flush(inode, filp, cd);
1554}
1555
1556static int release_flush_procfs(struct inode *inode, struct file *filp)
1557{
1558 struct cache_detail *cd = PDE_DATA(inode);
1559
1560 return release_flush(inode, filp, cd);
1561}
1562
1563static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1564 size_t count, loff_t *ppos)
1565{
1566 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1567
1568 return read_flush(filp, buf, count, ppos, cd);
1569}
1570
1571static ssize_t write_flush_procfs(struct file *filp,
1572 const char __user *buf,
1573 size_t count, loff_t *ppos)
1574{
1575 struct cache_detail *cd = PDE_DATA(file_inode(filp));
1576
1577 return write_flush(filp, buf, count, ppos, cd);
1578}
1579
1580static const struct file_operations cache_flush_operations_procfs = {
1581 .open = open_flush_procfs,
1582 .read = read_flush_procfs,
1583 .write = write_flush_procfs,
1584 .release = release_flush_procfs,
1585 .llseek = no_llseek,
1586};
1587
1588static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1589{
1590 struct sunrpc_net *sn;
1591
1592 if (cd->u.procfs.proc_ent == NULL)
1593 return;
1594 if (cd->u.procfs.flush_ent)
1595 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1596 if (cd->u.procfs.channel_ent)
1597 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1598 if (cd->u.procfs.content_ent)
1599 remove_proc_entry("content", cd->u.procfs.proc_ent);
1600 cd->u.procfs.proc_ent = NULL;
1601 sn = net_generic(net, sunrpc_net_id);
1602 remove_proc_entry(cd->name, sn->proc_net_rpc);
1603}
1604
1605#ifdef CONFIG_PROC_FS
1606static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1607{
1608 struct proc_dir_entry *p;
1609 struct sunrpc_net *sn;
1610
1611 sn = net_generic(net, sunrpc_net_id);
1612 cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1613 if (cd->u.procfs.proc_ent == NULL)
1614 goto out_nomem;
1615 cd->u.procfs.channel_ent = NULL;
1616 cd->u.procfs.content_ent = NULL;
1617
1618 p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1619 cd->u.procfs.proc_ent,
1620 &cache_flush_operations_procfs, cd);
1621 cd->u.procfs.flush_ent = p;
1622 if (p == NULL)
1623 goto out_nomem;
1624
1625 if (cd->cache_request || cd->cache_parse) {
1626 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1627 cd->u.procfs.proc_ent,
1628 &cache_file_operations_procfs, cd);
1629 cd->u.procfs.channel_ent = p;
1630 if (p == NULL)
1631 goto out_nomem;
1632 }
1633 if (cd->cache_show) {
1634 p = proc_create_data("content", S_IFREG|S_IRUSR,
1635 cd->u.procfs.proc_ent,
1636 &content_file_operations_procfs, cd);
1637 cd->u.procfs.content_ent = p;
1638 if (p == NULL)
1639 goto out_nomem;
1640 }
1641 return 0;
1642out_nomem:
1643 remove_cache_proc_entries(cd, net);
1644 return -ENOMEM;
1645}
1646#else /* CONFIG_PROC_FS */
1647static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1648{
1649 return 0;
1650}
1651#endif
1652
1653void __init cache_initialize(void)
1654{
1655 INIT_DEFERRABLE_WORK(&cache_cleaner, do_cache_clean);
1656}
1657
1658int cache_register_net(struct cache_detail *cd, struct net *net)
1659{
1660 int ret;
1661
1662 sunrpc_init_cache_detail(cd);
1663 ret = create_cache_proc_entries(cd, net);
1664 if (ret)
1665 sunrpc_destroy_cache_detail(cd);
1666 return ret;
1667}
1668EXPORT_SYMBOL_GPL(cache_register_net);
1669
1670void cache_unregister_net(struct cache_detail *cd, struct net *net)
1671{
1672 remove_cache_proc_entries(cd, net);
1673 sunrpc_destroy_cache_detail(cd);
1674}
1675EXPORT_SYMBOL_GPL(cache_unregister_net);
1676
1677struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1678{
1679 struct cache_detail *cd;
1680
1681 cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1682 if (cd == NULL)
1683 return ERR_PTR(-ENOMEM);
1684
1685 cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *),
1686 GFP_KERNEL);
1687 if (cd->hash_table == NULL) {
1688 kfree(cd);
1689 return ERR_PTR(-ENOMEM);
1690 }
1691 cd->net = net;
1692 return cd;
1693}
1694EXPORT_SYMBOL_GPL(cache_create_net);
1695
1696void cache_destroy_net(struct cache_detail *cd, struct net *net)
1697{
1698 kfree(cd->hash_table);
1699 kfree(cd);
1700}
1701EXPORT_SYMBOL_GPL(cache_destroy_net);
1702
1703static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1704 size_t count, loff_t *ppos)
1705{
1706 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1707
1708 return cache_read(filp, buf, count, ppos, cd);
1709}
1710
1711static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1712 size_t count, loff_t *ppos)
1713{
1714 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1715
1716 return cache_write(filp, buf, count, ppos, cd);
1717}
1718
1719static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1720{
1721 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1722
1723 return cache_poll(filp, wait, cd);
1724}
1725
1726static long cache_ioctl_pipefs(struct file *filp,
1727 unsigned int cmd, unsigned long arg)
1728{
1729 struct inode *inode = file_inode(filp);
1730 struct cache_detail *cd = RPC_I(inode)->private;
1731
1732 return cache_ioctl(inode, filp, cmd, arg, cd);
1733}
1734
1735static int cache_open_pipefs(struct inode *inode, struct file *filp)
1736{
1737 struct cache_detail *cd = RPC_I(inode)->private;
1738
1739 return cache_open(inode, filp, cd);
1740}
1741
1742static int cache_release_pipefs(struct inode *inode, struct file *filp)
1743{
1744 struct cache_detail *cd = RPC_I(inode)->private;
1745
1746 return cache_release(inode, filp, cd);
1747}
1748
1749const struct file_operations cache_file_operations_pipefs = {
1750 .owner = THIS_MODULE,
1751 .llseek = no_llseek,
1752 .read = cache_read_pipefs,
1753 .write = cache_write_pipefs,
1754 .poll = cache_poll_pipefs,
1755 .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1756 .open = cache_open_pipefs,
1757 .release = cache_release_pipefs,
1758};
1759
1760static int content_open_pipefs(struct inode *inode, struct file *filp)
1761{
1762 struct cache_detail *cd = RPC_I(inode)->private;
1763
1764 return content_open(inode, filp, cd);
1765}
1766
1767static int content_release_pipefs(struct inode *inode, struct file *filp)
1768{
1769 struct cache_detail *cd = RPC_I(inode)->private;
1770
1771 return content_release(inode, filp, cd);
1772}
1773
1774const struct file_operations content_file_operations_pipefs = {
1775 .open = content_open_pipefs,
1776 .read = seq_read,
1777 .llseek = seq_lseek,
1778 .release = content_release_pipefs,
1779};
1780
1781static int open_flush_pipefs(struct inode *inode, struct file *filp)
1782{
1783 struct cache_detail *cd = RPC_I(inode)->private;
1784
1785 return open_flush(inode, filp, cd);
1786}
1787
1788static int release_flush_pipefs(struct inode *inode, struct file *filp)
1789{
1790 struct cache_detail *cd = RPC_I(inode)->private;
1791
1792 return release_flush(inode, filp, cd);
1793}
1794
1795static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1796 size_t count, loff_t *ppos)
1797{
1798 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1799
1800 return read_flush(filp, buf, count, ppos, cd);
1801}
1802
1803static ssize_t write_flush_pipefs(struct file *filp,
1804 const char __user *buf,
1805 size_t count, loff_t *ppos)
1806{
1807 struct cache_detail *cd = RPC_I(file_inode(filp))->private;
1808
1809 return write_flush(filp, buf, count, ppos, cd);
1810}
1811
1812const struct file_operations cache_flush_operations_pipefs = {
1813 .open = open_flush_pipefs,
1814 .read = read_flush_pipefs,
1815 .write = write_flush_pipefs,
1816 .release = release_flush_pipefs,
1817 .llseek = no_llseek,
1818};
1819
1820int sunrpc_cache_register_pipefs(struct dentry *parent,
1821 const char *name, umode_t umode,
1822 struct cache_detail *cd)
1823{
1824 struct dentry *dir = rpc_create_cache_dir(parent, name, umode, cd);
1825 if (IS_ERR(dir))
1826 return PTR_ERR(dir);
1827 cd->u.pipefs.dir = dir;
1828 return 0;
1829}
1830EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1831
1832void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1833{
1834 rpc_remove_cache_dir(cd->u.pipefs.dir);
1835 cd->u.pipefs.dir = NULL;
1836}
1837EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1838