blob: 7026b0866b7b0d50b0003b15bb14fde24a569a65 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080029#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <asm/ioctls.h>
31#include <linux/sunrpc/types.h>
32#include <linux/sunrpc/cache.h>
33#include <linux/sunrpc/stats.h>
34
35#define RPCDBG_FACILITY RPCDBG_CACHE
36
37static void cache_defer_req(struct cache_req *req, struct cache_head *item);
38static void cache_revisit_request(struct cache_head *item);
39
Adrian Bunk74cae612006-03-27 01:15:10 -080040static void cache_init(struct cache_head *h)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
42 time_t now = get_seconds();
43 h->next = NULL;
44 h->flags = 0;
NeilBrownbaab9352006-03-27 01:15:09 -080045 kref_init(&h->ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 h->expiry_time = now + CACHE_NEW_EXPIRY;
47 h->last_refresh = now;
48}
49
NeilBrown15a5f6b2006-03-27 01:15:02 -080050struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
51 struct cache_head *key, int hash)
52{
53 struct cache_head **head, **hp;
54 struct cache_head *new = NULL;
55
56 head = &detail->hash_table[hash];
57
58 read_lock(&detail->hash_lock);
59
60 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
61 struct cache_head *tmp = *hp;
62 if (detail->match(tmp, key)) {
63 cache_get(tmp);
64 read_unlock(&detail->hash_lock);
65 return tmp;
66 }
67 }
68 read_unlock(&detail->hash_lock);
69 /* Didn't find anything, insert an empty entry */
70
71 new = detail->alloc();
72 if (!new)
73 return NULL;
74 cache_init(new);
75
76 write_lock(&detail->hash_lock);
77
78 /* check if entry appeared while we slept */
79 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
80 struct cache_head *tmp = *hp;
81 if (detail->match(tmp, key)) {
82 cache_get(tmp);
83 write_unlock(&detail->hash_lock);
NeilBrownbaab9352006-03-27 01:15:09 -080084 cache_put(new, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -080085 return tmp;
86 }
87 }
88 detail->init(new, key);
89 new->next = *head;
90 *head = new;
91 detail->entries++;
92 cache_get(new);
93 write_unlock(&detail->hash_lock);
94
95 return new;
96}
97EXPORT_SYMBOL(sunrpc_cache_lookup);
98
NeilBrownebd0cb12006-03-27 01:15:08 -080099
100static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
101
102static int cache_fresh_locked(struct cache_head *head, time_t expiry)
103{
104 head->expiry_time = expiry;
105 head->last_refresh = get_seconds();
106 return !test_and_set_bit(CACHE_VALID, &head->flags);
107}
108
109static void cache_fresh_unlocked(struct cache_head *head,
110 struct cache_detail *detail, int new)
111{
112 if (new)
113 cache_revisit_request(head);
114 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
115 cache_revisit_request(head);
116 queue_loose(detail, head);
117 }
118}
119
NeilBrown15a5f6b2006-03-27 01:15:02 -0800120struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
121 struct cache_head *new, struct cache_head *old, int hash)
122{
123 /* The 'old' entry is to be replaced by 'new'.
124 * If 'old' is not VALID, we update it directly,
125 * otherwise we need to replace it
126 */
127 struct cache_head **head;
128 struct cache_head *tmp;
NeilBrownebd0cb12006-03-27 01:15:08 -0800129 int is_new;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800130
131 if (!test_bit(CACHE_VALID, &old->flags)) {
132 write_lock(&detail->hash_lock);
133 if (!test_bit(CACHE_VALID, &old->flags)) {
134 if (test_bit(CACHE_NEGATIVE, &new->flags))
135 set_bit(CACHE_NEGATIVE, &old->flags);
136 else
137 detail->update(old, new);
NeilBrownebd0cb12006-03-27 01:15:08 -0800138 is_new = cache_fresh_locked(old, new->expiry_time);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800139 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800140 cache_fresh_unlocked(old, detail, is_new);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800141 return old;
142 }
143 write_unlock(&detail->hash_lock);
144 }
145 /* We need to insert a new entry */
146 tmp = detail->alloc();
147 if (!tmp) {
NeilBrownbaab9352006-03-27 01:15:09 -0800148 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800149 return NULL;
150 }
151 cache_init(tmp);
152 detail->init(tmp, old);
153 head = &detail->hash_table[hash];
154
155 write_lock(&detail->hash_lock);
156 if (test_bit(CACHE_NEGATIVE, &new->flags))
157 set_bit(CACHE_NEGATIVE, &tmp->flags);
158 else
159 detail->update(tmp, new);
160 tmp->next = *head;
161 *head = tmp;
NeilBrownf2d39582006-05-22 22:35:25 -0700162 detail->entries++;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800163 cache_get(tmp);
NeilBrownebd0cb12006-03-27 01:15:08 -0800164 is_new = cache_fresh_locked(tmp, new->expiry_time);
165 cache_fresh_locked(old, 0);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800166 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800167 cache_fresh_unlocked(tmp, detail, is_new);
168 cache_fresh_unlocked(old, detail, 0);
NeilBrownbaab9352006-03-27 01:15:09 -0800169 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800170 return tmp;
171}
172EXPORT_SYMBOL(sunrpc_cache_update);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
174static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
175/*
176 * This is the generic cache management routine for all
177 * the authentication caches.
178 * It checks the currency of a cache item and will (later)
179 * initiate an upcall to fill it if needed.
180 *
181 *
182 * Returns 0 if the cache_head can be used, or cache_puts it and returns
183 * -EAGAIN if upcall is pending,
184 * -ENOENT if cache entry was negative
185 */
186int cache_check(struct cache_detail *detail,
187 struct cache_head *h, struct cache_req *rqstp)
188{
189 int rv;
190 long refresh_age, age;
191
192 /* First decide return status as best we can */
193 if (!test_bit(CACHE_VALID, &h->flags) ||
194 h->expiry_time < get_seconds())
195 rv = -EAGAIN;
196 else if (detail->flush_time > h->last_refresh)
197 rv = -EAGAIN;
198 else {
199 /* entry is valid */
200 if (test_bit(CACHE_NEGATIVE, &h->flags))
201 rv = -ENOENT;
202 else rv = 0;
203 }
204
205 /* now see if we want to start an upcall */
206 refresh_age = (h->expiry_time - h->last_refresh);
207 age = get_seconds() - h->last_refresh;
208
209 if (rqstp == NULL) {
210 if (rv == -EAGAIN)
211 rv = -ENOENT;
212 } else if (rv == -EAGAIN || age > refresh_age/2) {
213 dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age);
214 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
215 switch (cache_make_upcall(detail, h)) {
216 case -EINVAL:
217 clear_bit(CACHE_PENDING, &h->flags);
218 if (rv == -EAGAIN) {
219 set_bit(CACHE_NEGATIVE, &h->flags);
NeilBrownebd0cb12006-03-27 01:15:08 -0800220 cache_fresh_unlocked(h, detail,
221 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 rv = -ENOENT;
223 }
224 break;
225
226 case -EAGAIN:
227 clear_bit(CACHE_PENDING, &h->flags);
228 cache_revisit_request(h);
229 break;
230 }
231 }
232 }
233
234 if (rv == -EAGAIN)
235 cache_defer_req(rqstp, h);
236
NeilBrown4013ede2006-03-27 01:15:07 -0800237 if (rv)
NeilBrownbaab9352006-03-27 01:15:09 -0800238 cache_put(h, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 return rv;
240}
241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242/*
243 * caches need to be periodically cleaned.
244 * For this we maintain a list of cache_detail and
245 * a current pointer into that list and into the table
246 * for that entry.
247 *
248 * Each time clean_cache is called it finds the next non-empty entry
249 * in the current table and walks the list in that entry
250 * looking for entries that can be removed.
251 *
252 * An entry gets removed if:
253 * - The expiry is before current time
254 * - The last_refresh time is before the flush_time for that cache
255 *
256 * later we might drop old entries with non-NEVER expiry if that table
257 * is getting 'full' for some definition of 'full'
258 *
259 * The question of "how often to scan a table" is an interesting one
260 * and is answered in part by the use of the "nextcheck" field in the
261 * cache_detail.
262 * When a scan of a table begins, the nextcheck field is set to a time
263 * that is well into the future.
264 * While scanning, if an expiry time is found that is earlier than the
265 * current nextcheck time, nextcheck is set to that expiry time.
266 * If the flush_time is ever set to a time earlier than the nextcheck
267 * time, the nextcheck time is then set to that flush_time.
268 *
269 * A table is then only scanned if the current time is at least
270 * the nextcheck time.
271 *
272 */
273
274static LIST_HEAD(cache_list);
275static DEFINE_SPINLOCK(cache_list_lock);
276static struct cache_detail *current_detail;
277static int current_index;
278
279static struct file_operations cache_file_operations;
280static struct file_operations content_file_operations;
281static struct file_operations cache_flush_operations;
282
283static void do_cache_clean(void *data);
284static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL);
285
286void cache_register(struct cache_detail *cd)
287{
288 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
289 if (cd->proc_ent) {
290 struct proc_dir_entry *p;
Bruce Allanf35279d2005-09-06 15:17:08 -0700291 cd->proc_ent->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 cd->channel_ent = cd->content_ent = NULL;
293
294 p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR,
295 cd->proc_ent);
296 cd->flush_ent = p;
297 if (p) {
298 p->proc_fops = &cache_flush_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700299 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 p->data = cd;
301 }
302
303 if (cd->cache_request || cd->cache_parse) {
304 p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR,
305 cd->proc_ent);
306 cd->channel_ent = p;
307 if (p) {
308 p->proc_fops = &cache_file_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700309 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 p->data = cd;
311 }
312 }
313 if (cd->cache_show) {
314 p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR,
315 cd->proc_ent);
316 cd->content_ent = p;
317 if (p) {
318 p->proc_fops = &content_file_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700319 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 p->data = cd;
321 }
322 }
323 }
324 rwlock_init(&cd->hash_lock);
325 INIT_LIST_HEAD(&cd->queue);
326 spin_lock(&cache_list_lock);
327 cd->nextcheck = 0;
328 cd->entries = 0;
329 atomic_set(&cd->readers, 0);
330 cd->last_close = 0;
331 cd->last_warn = -1;
332 list_add(&cd->others, &cache_list);
333 spin_unlock(&cache_list_lock);
334
335 /* start the cleaning process */
336 schedule_work(&cache_cleaner);
337}
338
339int cache_unregister(struct cache_detail *cd)
340{
341 cache_purge(cd);
342 spin_lock(&cache_list_lock);
343 write_lock(&cd->hash_lock);
344 if (cd->entries || atomic_read(&cd->inuse)) {
345 write_unlock(&cd->hash_lock);
346 spin_unlock(&cache_list_lock);
347 return -EBUSY;
348 }
349 if (current_detail == cd)
350 current_detail = NULL;
351 list_del_init(&cd->others);
352 write_unlock(&cd->hash_lock);
353 spin_unlock(&cache_list_lock);
354 if (cd->proc_ent) {
355 if (cd->flush_ent)
356 remove_proc_entry("flush", cd->proc_ent);
357 if (cd->channel_ent)
358 remove_proc_entry("channel", cd->proc_ent);
359 if (cd->content_ent)
360 remove_proc_entry("content", cd->proc_ent);
361
362 cd->proc_ent = NULL;
363 remove_proc_entry(cd->name, proc_net_rpc);
364 }
365 if (list_empty(&cache_list)) {
366 /* module must be being unloaded so its safe to kill the worker */
367 cancel_delayed_work(&cache_cleaner);
368 flush_scheduled_work();
369 }
370 return 0;
371}
372
373/* clean cache tries to find something to clean
374 * and cleans it.
375 * It returns 1 if it cleaned something,
376 * 0 if it didn't find anything this time
377 * -1 if it fell off the end of the list.
378 */
379static int cache_clean(void)
380{
381 int rv = 0;
382 struct list_head *next;
383
384 spin_lock(&cache_list_lock);
385
386 /* find a suitable table if we don't already have one */
387 while (current_detail == NULL ||
388 current_index >= current_detail->hash_size) {
389 if (current_detail)
390 next = current_detail->others.next;
391 else
392 next = cache_list.next;
393 if (next == &cache_list) {
394 current_detail = NULL;
395 spin_unlock(&cache_list_lock);
396 return -1;
397 }
398 current_detail = list_entry(next, struct cache_detail, others);
399 if (current_detail->nextcheck > get_seconds())
400 current_index = current_detail->hash_size;
401 else {
402 current_index = 0;
403 current_detail->nextcheck = get_seconds()+30*60;
404 }
405 }
406
407 /* find a non-empty bucket in the table */
408 while (current_detail &&
409 current_index < current_detail->hash_size &&
410 current_detail->hash_table[current_index] == NULL)
411 current_index++;
412
413 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
414
415 if (current_detail && current_index < current_detail->hash_size) {
416 struct cache_head *ch, **cp;
417 struct cache_detail *d;
418
419 write_lock(&current_detail->hash_lock);
420
421 /* Ok, now to clean this strand */
422
423 cp = & current_detail->hash_table[current_index];
424 ch = *cp;
425 for (; ch; cp= & ch->next, ch= *cp) {
426 if (current_detail->nextcheck > ch->expiry_time)
427 current_detail->nextcheck = ch->expiry_time+1;
428 if (ch->expiry_time >= get_seconds()
429 && ch->last_refresh >= current_detail->flush_time
430 )
431 continue;
432 if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
433 queue_loose(current_detail, ch);
434
NeilBrownbaab9352006-03-27 01:15:09 -0800435 if (atomic_read(&ch->ref.refcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 break;
437 }
438 if (ch) {
439 *cp = ch->next;
440 ch->next = NULL;
441 current_detail->entries--;
442 rv = 1;
443 }
444 write_unlock(&current_detail->hash_lock);
445 d = current_detail;
446 if (!ch)
447 current_index ++;
448 spin_unlock(&cache_list_lock);
449 if (ch)
NeilBrownbaab9352006-03-27 01:15:09 -0800450 cache_put(ch, d);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 } else
452 spin_unlock(&cache_list_lock);
453
454 return rv;
455}
456
457/*
458 * We want to regularly clean the cache, so we need to schedule some work ...
459 */
460static void do_cache_clean(void *data)
461{
462 int delay = 5;
463 if (cache_clean() == -1)
464 delay = 30*HZ;
465
466 if (list_empty(&cache_list))
467 delay = 0;
468
469 if (delay)
470 schedule_delayed_work(&cache_cleaner, delay);
471}
472
473
474/*
475 * Clean all caches promptly. This just calls cache_clean
476 * repeatedly until we are sure that every cache has had a chance to
477 * be fully cleaned
478 */
479void cache_flush(void)
480{
481 while (cache_clean() != -1)
482 cond_resched();
483 while (cache_clean() != -1)
484 cond_resched();
485}
486
487void cache_purge(struct cache_detail *detail)
488{
489 detail->flush_time = LONG_MAX;
490 detail->nextcheck = get_seconds();
491 cache_flush();
492 detail->flush_time = 1;
493}
494
495
496
497/*
498 * Deferral and Revisiting of Requests.
499 *
500 * If a cache lookup finds a pending entry, we
501 * need to defer the request and revisit it later.
502 * All deferred requests are stored in a hash table,
503 * indexed by "struct cache_head *".
504 * As it may be wasteful to store a whole request
505 * structure, we allow the request to provide a
506 * deferred form, which must contain a
507 * 'struct cache_deferred_req'
508 * This cache_deferred_req contains a method to allow
509 * it to be revisited when cache info is available
510 */
511
512#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
513#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
514
515#define DFR_MAX 300 /* ??? */
516
517static DEFINE_SPINLOCK(cache_defer_lock);
518static LIST_HEAD(cache_defer_list);
519static struct list_head cache_defer_hash[DFR_HASHSIZE];
520static int cache_defer_cnt;
521
522static void cache_defer_req(struct cache_req *req, struct cache_head *item)
523{
524 struct cache_deferred_req *dreq;
525 int hash = DFR_HASH(item);
526
527 dreq = req->defer(req);
528 if (dreq == NULL)
529 return;
530
531 dreq->item = item;
532 dreq->recv_time = get_seconds();
533
534 spin_lock(&cache_defer_lock);
535
536 list_add(&dreq->recent, &cache_defer_list);
537
538 if (cache_defer_hash[hash].next == NULL)
539 INIT_LIST_HEAD(&cache_defer_hash[hash]);
540 list_add(&dreq->hash, &cache_defer_hash[hash]);
541
542 /* it is in, now maybe clean up */
543 dreq = NULL;
544 if (++cache_defer_cnt > DFR_MAX) {
545 /* too much in the cache, randomly drop
546 * first or last
547 */
548 if (net_random()&1)
549 dreq = list_entry(cache_defer_list.next,
550 struct cache_deferred_req,
551 recent);
552 else
553 dreq = list_entry(cache_defer_list.prev,
554 struct cache_deferred_req,
555 recent);
556 list_del(&dreq->recent);
557 list_del(&dreq->hash);
558 cache_defer_cnt--;
559 }
560 spin_unlock(&cache_defer_lock);
561
562 if (dreq) {
563 /* there was one too many */
564 dreq->revisit(dreq, 1);
565 }
NeilBrown4013ede2006-03-27 01:15:07 -0800566 if (!test_bit(CACHE_PENDING, &item->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 /* must have just been validated... */
568 cache_revisit_request(item);
569 }
570}
571
572static void cache_revisit_request(struct cache_head *item)
573{
574 struct cache_deferred_req *dreq;
575 struct list_head pending;
576
577 struct list_head *lp;
578 int hash = DFR_HASH(item);
579
580 INIT_LIST_HEAD(&pending);
581 spin_lock(&cache_defer_lock);
582
583 lp = cache_defer_hash[hash].next;
584 if (lp) {
585 while (lp != &cache_defer_hash[hash]) {
586 dreq = list_entry(lp, struct cache_deferred_req, hash);
587 lp = lp->next;
588 if (dreq->item == item) {
589 list_del(&dreq->hash);
590 list_move(&dreq->recent, &pending);
591 cache_defer_cnt--;
592 }
593 }
594 }
595 spin_unlock(&cache_defer_lock);
596
597 while (!list_empty(&pending)) {
598 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
599 list_del_init(&dreq->recent);
600 dreq->revisit(dreq, 0);
601 }
602}
603
604void cache_clean_deferred(void *owner)
605{
606 struct cache_deferred_req *dreq, *tmp;
607 struct list_head pending;
608
609
610 INIT_LIST_HEAD(&pending);
611 spin_lock(&cache_defer_lock);
612
613 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
614 if (dreq->owner == owner) {
615 list_del(&dreq->hash);
616 list_move(&dreq->recent, &pending);
617 cache_defer_cnt--;
618 }
619 }
620 spin_unlock(&cache_defer_lock);
621
622 while (!list_empty(&pending)) {
623 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
624 list_del_init(&dreq->recent);
625 dreq->revisit(dreq, 1);
626 }
627}
628
629/*
630 * communicate with user-space
631 *
632 * We have a magic /proc file - /proc/sunrpc/cache
633 * On read, you get a full request, or block
634 * On write, an update request is processed
635 * Poll works if anything to read, and always allows write
636 *
637 * Implemented by linked list of requests. Each open file has
638 * a ->private that also exists in this list. New request are added
639 * to the end and may wakeup and preceding readers.
640 * New readers are added to the head. If, on read, an item is found with
641 * CACHE_UPCALLING clear, we free it from the list.
642 *
643 */
644
645static DEFINE_SPINLOCK(queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800646static DEFINE_MUTEX(queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647
648struct cache_queue {
649 struct list_head list;
650 int reader; /* if 0, then request */
651};
652struct cache_request {
653 struct cache_queue q;
654 struct cache_head *item;
655 char * buf;
656 int len;
657 int readers;
658};
659struct cache_reader {
660 struct cache_queue q;
661 int offset; /* if non-0, we have a refcnt on next request */
662};
663
664static ssize_t
665cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
666{
667 struct cache_reader *rp = filp->private_data;
668 struct cache_request *rq;
669 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
670 int err;
671
672 if (count == 0)
673 return 0;
674
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800675 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 * readers on this file */
677 again:
678 spin_lock(&queue_lock);
679 /* need to find next request */
680 while (rp->q.list.next != &cd->queue &&
681 list_entry(rp->q.list.next, struct cache_queue, list)
682 ->reader) {
683 struct list_head *next = rp->q.list.next;
684 list_move(&rp->q.list, next);
685 }
686 if (rp->q.list.next == &cd->queue) {
687 spin_unlock(&queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800688 mutex_unlock(&queue_io_mutex);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800689 BUG_ON(rp->offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 return 0;
691 }
692 rq = container_of(rp->q.list.next, struct cache_request, q.list);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800693 BUG_ON(rq->q.reader);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 if (rp->offset == 0)
695 rq->readers++;
696 spin_unlock(&queue_lock);
697
698 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
699 err = -EAGAIN;
700 spin_lock(&queue_lock);
701 list_move(&rp->q.list, &rq->q.list);
702 spin_unlock(&queue_lock);
703 } else {
704 if (rp->offset + count > rq->len)
705 count = rq->len - rp->offset;
706 err = -EFAULT;
707 if (copy_to_user(buf, rq->buf + rp->offset, count))
708 goto out;
709 rp->offset += count;
710 if (rp->offset >= rq->len) {
711 rp->offset = 0;
712 spin_lock(&queue_lock);
713 list_move(&rp->q.list, &rq->q.list);
714 spin_unlock(&queue_lock);
715 }
716 err = 0;
717 }
718 out:
719 if (rp->offset == 0) {
720 /* need to release rq */
721 spin_lock(&queue_lock);
722 rq->readers--;
723 if (rq->readers == 0 &&
724 !test_bit(CACHE_PENDING, &rq->item->flags)) {
725 list_del(&rq->q.list);
726 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800727 cache_put(rq->item, cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 kfree(rq->buf);
729 kfree(rq);
730 } else
731 spin_unlock(&queue_lock);
732 }
733 if (err == -EAGAIN)
734 goto again;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800735 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 return err ? err : count;
737}
738
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800739static char write_buf[8192]; /* protected by queue_io_mutex */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
741static ssize_t
742cache_write(struct file *filp, const char __user *buf, size_t count,
743 loff_t *ppos)
744{
745 int err;
746 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
747
748 if (count == 0)
749 return 0;
750 if (count >= sizeof(write_buf))
751 return -EINVAL;
752
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800753 mutex_lock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754
755 if (copy_from_user(write_buf, buf, count)) {
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800756 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 return -EFAULT;
758 }
759 write_buf[count] = '\0';
760 if (cd->cache_parse)
761 err = cd->cache_parse(cd, write_buf, count);
762 else
763 err = -EINVAL;
764
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800765 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 return err ? err : count;
767}
768
769static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
770
771static unsigned int
772cache_poll(struct file *filp, poll_table *wait)
773{
774 unsigned int mask;
775 struct cache_reader *rp = filp->private_data;
776 struct cache_queue *cq;
777 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
778
779 poll_wait(filp, &queue_wait, wait);
780
781 /* alway allow write */
782 mask = POLL_OUT | POLLWRNORM;
783
784 if (!rp)
785 return mask;
786
787 spin_lock(&queue_lock);
788
789 for (cq= &rp->q; &cq->list != &cd->queue;
790 cq = list_entry(cq->list.next, struct cache_queue, list))
791 if (!cq->reader) {
792 mask |= POLLIN | POLLRDNORM;
793 break;
794 }
795 spin_unlock(&queue_lock);
796 return mask;
797}
798
799static int
800cache_ioctl(struct inode *ino, struct file *filp,
801 unsigned int cmd, unsigned long arg)
802{
803 int len = 0;
804 struct cache_reader *rp = filp->private_data;
805 struct cache_queue *cq;
806 struct cache_detail *cd = PDE(ino)->data;
807
808 if (cmd != FIONREAD || !rp)
809 return -EINVAL;
810
811 spin_lock(&queue_lock);
812
813 /* only find the length remaining in current request,
814 * or the length of the next request
815 */
816 for (cq= &rp->q; &cq->list != &cd->queue;
817 cq = list_entry(cq->list.next, struct cache_queue, list))
818 if (!cq->reader) {
819 struct cache_request *cr =
820 container_of(cq, struct cache_request, q);
821 len = cr->len - rp->offset;
822 break;
823 }
824 spin_unlock(&queue_lock);
825
826 return put_user(len, (int __user *)arg);
827}
828
829static int
830cache_open(struct inode *inode, struct file *filp)
831{
832 struct cache_reader *rp = NULL;
833
834 nonseekable_open(inode, filp);
835 if (filp->f_mode & FMODE_READ) {
836 struct cache_detail *cd = PDE(inode)->data;
837
838 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
839 if (!rp)
840 return -ENOMEM;
841 rp->offset = 0;
842 rp->q.reader = 1;
843 atomic_inc(&cd->readers);
844 spin_lock(&queue_lock);
845 list_add(&rp->q.list, &cd->queue);
846 spin_unlock(&queue_lock);
847 }
848 filp->private_data = rp;
849 return 0;
850}
851
852static int
853cache_release(struct inode *inode, struct file *filp)
854{
855 struct cache_reader *rp = filp->private_data;
856 struct cache_detail *cd = PDE(inode)->data;
857
858 if (rp) {
859 spin_lock(&queue_lock);
860 if (rp->offset) {
861 struct cache_queue *cq;
862 for (cq= &rp->q; &cq->list != &cd->queue;
863 cq = list_entry(cq->list.next, struct cache_queue, list))
864 if (!cq->reader) {
865 container_of(cq, struct cache_request, q)
866 ->readers--;
867 break;
868 }
869 rp->offset = 0;
870 }
871 list_del(&rp->q.list);
872 spin_unlock(&queue_lock);
873
874 filp->private_data = NULL;
875 kfree(rp);
876
877 cd->last_close = get_seconds();
878 atomic_dec(&cd->readers);
879 }
880 return 0;
881}
882
883
884
885static struct file_operations cache_file_operations = {
886 .owner = THIS_MODULE,
887 .llseek = no_llseek,
888 .read = cache_read,
889 .write = cache_write,
890 .poll = cache_poll,
891 .ioctl = cache_ioctl, /* for FIONREAD */
892 .open = cache_open,
893 .release = cache_release,
894};
895
896
897static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
898{
899 struct cache_queue *cq;
900 spin_lock(&queue_lock);
901 list_for_each_entry(cq, &detail->queue, list)
902 if (!cq->reader) {
903 struct cache_request *cr = container_of(cq, struct cache_request, q);
904 if (cr->item != ch)
905 continue;
906 if (cr->readers != 0)
NeilBrown4013ede2006-03-27 01:15:07 -0800907 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 list_del(&cr->q.list);
909 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800910 cache_put(cr->item, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 kfree(cr->buf);
912 kfree(cr);
913 return;
914 }
915 spin_unlock(&queue_lock);
916}
917
918/*
919 * Support routines for text-based upcalls.
920 * Fields are separated by spaces.
921 * Fields are either mangled to quote space tab newline slosh with slosh
922 * or a hexified with a leading \x
923 * Record is terminated with newline.
924 *
925 */
926
927void qword_add(char **bpp, int *lp, char *str)
928{
929 char *bp = *bpp;
930 int len = *lp;
931 char c;
932
933 if (len < 0) return;
934
935 while ((c=*str++) && len)
936 switch(c) {
937 case ' ':
938 case '\t':
939 case '\n':
940 case '\\':
941 if (len >= 4) {
942 *bp++ = '\\';
943 *bp++ = '0' + ((c & 0300)>>6);
944 *bp++ = '0' + ((c & 0070)>>3);
945 *bp++ = '0' + ((c & 0007)>>0);
946 }
947 len -= 4;
948 break;
949 default:
950 *bp++ = c;
951 len--;
952 }
953 if (c || len <1) len = -1;
954 else {
955 *bp++ = ' ';
956 len--;
957 }
958 *bpp = bp;
959 *lp = len;
960}
961
962void qword_addhex(char **bpp, int *lp, char *buf, int blen)
963{
964 char *bp = *bpp;
965 int len = *lp;
966
967 if (len < 0) return;
968
969 if (len > 2) {
970 *bp++ = '\\';
971 *bp++ = 'x';
972 len -= 2;
973 while (blen && len >= 2) {
974 unsigned char c = *buf++;
975 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
976 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
977 len -= 2;
978 blen--;
979 }
980 }
981 if (blen || len<1) len = -1;
982 else {
983 *bp++ = ' ';
984 len--;
985 }
986 *bpp = bp;
987 *lp = len;
988}
989
990static void warn_no_listener(struct cache_detail *detail)
991{
992 if (detail->last_warn != detail->last_close) {
993 detail->last_warn = detail->last_close;
994 if (detail->warn_no_listener)
995 detail->warn_no_listener(detail);
996 }
997}
998
999/*
1000 * register an upcall request to user-space.
1001 * Each request is at most one page long.
1002 */
1003static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
1004{
1005
1006 char *buf;
1007 struct cache_request *crq;
1008 char *bp;
1009 int len;
1010
1011 if (detail->cache_request == NULL)
1012 return -EINVAL;
1013
1014 if (atomic_read(&detail->readers) == 0 &&
1015 detail->last_close < get_seconds() - 30) {
1016 warn_no_listener(detail);
1017 return -EINVAL;
1018 }
1019
1020 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1021 if (!buf)
1022 return -EAGAIN;
1023
1024 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1025 if (!crq) {
1026 kfree(buf);
1027 return -EAGAIN;
1028 }
1029
1030 bp = buf; len = PAGE_SIZE;
1031
1032 detail->cache_request(detail, h, &bp, &len);
1033
1034 if (len < 0) {
1035 kfree(buf);
1036 kfree(crq);
1037 return -EAGAIN;
1038 }
1039 crq->q.reader = 0;
1040 crq->item = cache_get(h);
1041 crq->buf = buf;
1042 crq->len = PAGE_SIZE - len;
1043 crq->readers = 0;
1044 spin_lock(&queue_lock);
1045 list_add_tail(&crq->q.list, &detail->queue);
1046 spin_unlock(&queue_lock);
1047 wake_up(&queue_wait);
1048 return 0;
1049}
1050
1051/*
1052 * parse a message from user-space and pass it
1053 * to an appropriate cache
1054 * Messages are, like requests, separated into fields by
1055 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1056 *
1057 * Message is
1058 * reply cachename expiry key ... content....
1059 *
1060 * key and content are both parsed by cache
1061 */
1062
1063#define isodigit(c) (isdigit(c) && c <= '7')
1064int qword_get(char **bpp, char *dest, int bufsize)
1065{
1066 /* return bytes copied, or -1 on error */
1067 char *bp = *bpp;
1068 int len = 0;
1069
1070 while (*bp == ' ') bp++;
1071
1072 if (bp[0] == '\\' && bp[1] == 'x') {
1073 /* HEX STRING */
1074 bp += 2;
1075 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) {
1076 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1077 bp++;
1078 byte <<= 4;
1079 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1080 *dest++ = byte;
1081 bp++;
1082 len++;
1083 }
1084 } else {
1085 /* text with \nnn octal quoting */
1086 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1087 if (*bp == '\\' &&
1088 isodigit(bp[1]) && (bp[1] <= '3') &&
1089 isodigit(bp[2]) &&
1090 isodigit(bp[3])) {
1091 int byte = (*++bp -'0');
1092 bp++;
1093 byte = (byte << 3) | (*bp++ - '0');
1094 byte = (byte << 3) | (*bp++ - '0');
1095 *dest++ = byte;
1096 len++;
1097 } else {
1098 *dest++ = *bp++;
1099 len++;
1100 }
1101 }
1102 }
1103
1104 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1105 return -1;
1106 while (*bp == ' ') bp++;
1107 *bpp = bp;
1108 *dest = '\0';
1109 return len;
1110}
1111
1112
1113/*
1114 * support /proc/sunrpc/cache/$CACHENAME/content
1115 * as a seqfile.
1116 * We call ->cache_show passing NULL for the item to
1117 * get a header, then pass each real item in the cache
1118 */
1119
1120struct handle {
1121 struct cache_detail *cd;
1122};
1123
1124static void *c_start(struct seq_file *m, loff_t *pos)
1125{
1126 loff_t n = *pos;
1127 unsigned hash, entry;
1128 struct cache_head *ch;
1129 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1130
1131
1132 read_lock(&cd->hash_lock);
1133 if (!n--)
1134 return SEQ_START_TOKEN;
1135 hash = n >> 32;
1136 entry = n & ((1LL<<32) - 1);
1137
1138 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1139 if (!entry--)
1140 return ch;
1141 n &= ~((1LL<<32) - 1);
1142 do {
1143 hash++;
1144 n += 1LL<<32;
1145 } while(hash < cd->hash_size &&
1146 cd->hash_table[hash]==NULL);
1147 if (hash >= cd->hash_size)
1148 return NULL;
1149 *pos = n+1;
1150 return cd->hash_table[hash];
1151}
1152
1153static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1154{
1155 struct cache_head *ch = p;
1156 int hash = (*pos >> 32);
1157 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1158
1159 if (p == SEQ_START_TOKEN)
1160 hash = 0;
1161 else if (ch->next == NULL) {
1162 hash++;
1163 *pos += 1LL<<32;
1164 } else {
1165 ++*pos;
1166 return ch->next;
1167 }
1168 *pos &= ~((1LL<<32) - 1);
1169 while (hash < cd->hash_size &&
1170 cd->hash_table[hash] == NULL) {
1171 hash++;
1172 *pos += 1LL<<32;
1173 }
1174 if (hash >= cd->hash_size)
1175 return NULL;
1176 ++*pos;
1177 return cd->hash_table[hash];
1178}
1179
1180static void c_stop(struct seq_file *m, void *p)
1181{
1182 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1183 read_unlock(&cd->hash_lock);
1184}
1185
1186static int c_show(struct seq_file *m, void *p)
1187{
1188 struct cache_head *cp = p;
1189 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1190
1191 if (p == SEQ_START_TOKEN)
1192 return cd->cache_show(m, cd, NULL);
1193
1194 ifdebug(CACHE)
NeilBrown4013ede2006-03-27 01:15:07 -08001195 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
NeilBrownbaab9352006-03-27 01:15:09 -08001196 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 cache_get(cp);
1198 if (cache_check(cd, cp, NULL))
1199 /* cache_check does a cache_put on failure */
1200 seq_printf(m, "# ");
1201 else
1202 cache_put(cp, cd);
1203
1204 return cd->cache_show(m, cd, cp);
1205}
1206
1207static struct seq_operations cache_content_op = {
1208 .start = c_start,
1209 .next = c_next,
1210 .stop = c_stop,
1211 .show = c_show,
1212};
1213
1214static int content_open(struct inode *inode, struct file *file)
1215{
1216 int res;
1217 struct handle *han;
1218 struct cache_detail *cd = PDE(inode)->data;
1219
1220 han = kmalloc(sizeof(*han), GFP_KERNEL);
1221 if (han == NULL)
1222 return -ENOMEM;
1223
1224 han->cd = cd;
1225
1226 res = seq_open(file, &cache_content_op);
1227 if (res)
1228 kfree(han);
1229 else
1230 ((struct seq_file *)file->private_data)->private = han;
1231
1232 return res;
1233}
1234static int content_release(struct inode *inode, struct file *file)
1235{
1236 struct seq_file *m = (struct seq_file *)file->private_data;
1237 struct handle *han = m->private;
1238 kfree(han);
1239 m->private = NULL;
1240 return seq_release(inode, file);
1241}
1242
1243static struct file_operations content_file_operations = {
1244 .open = content_open,
1245 .read = seq_read,
1246 .llseek = seq_lseek,
1247 .release = content_release,
1248};
1249
1250static ssize_t read_flush(struct file *file, char __user *buf,
1251 size_t count, loff_t *ppos)
1252{
1253 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1254 char tbuf[20];
1255 unsigned long p = *ppos;
1256 int len;
1257
1258 sprintf(tbuf, "%lu\n", cd->flush_time);
1259 len = strlen(tbuf);
1260 if (p >= len)
1261 return 0;
1262 len -= p;
1263 if (len > count) len = count;
1264 if (copy_to_user(buf, (void*)(tbuf+p), len))
1265 len = -EFAULT;
1266 else
1267 *ppos += len;
1268 return len;
1269}
1270
1271static ssize_t write_flush(struct file * file, const char __user * buf,
1272 size_t count, loff_t *ppos)
1273{
1274 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1275 char tbuf[20];
1276 char *ep;
1277 long flushtime;
1278 if (*ppos || count > sizeof(tbuf)-1)
1279 return -EINVAL;
1280 if (copy_from_user(tbuf, buf, count))
1281 return -EFAULT;
1282 tbuf[count] = 0;
1283 flushtime = simple_strtoul(tbuf, &ep, 0);
1284 if (*ep && *ep != '\n')
1285 return -EINVAL;
1286
1287 cd->flush_time = flushtime;
1288 cd->nextcheck = get_seconds();
1289 cache_flush();
1290
1291 *ppos += count;
1292 return count;
1293}
1294
1295static struct file_operations cache_flush_operations = {
1296 .open = nonseekable_open,
1297 .read = read_flush,
1298 .write = write_flush,
1299};