blob: 3ac4193a78edf2c0fcff4ae5257b50163c2a937f [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;
162 cache_get(tmp);
NeilBrownebd0cb12006-03-27 01:15:08 -0800163 is_new = cache_fresh_locked(tmp, new->expiry_time);
164 cache_fresh_locked(old, 0);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800165 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800166 cache_fresh_unlocked(tmp, detail, is_new);
167 cache_fresh_unlocked(old, detail, 0);
NeilBrownbaab9352006-03-27 01:15:09 -0800168 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800169 return tmp;
170}
171EXPORT_SYMBOL(sunrpc_cache_update);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
173static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
174/*
175 * This is the generic cache management routine for all
176 * the authentication caches.
177 * It checks the currency of a cache item and will (later)
178 * initiate an upcall to fill it if needed.
179 *
180 *
181 * Returns 0 if the cache_head can be used, or cache_puts it and returns
182 * -EAGAIN if upcall is pending,
183 * -ENOENT if cache entry was negative
184 */
185int cache_check(struct cache_detail *detail,
186 struct cache_head *h, struct cache_req *rqstp)
187{
188 int rv;
189 long refresh_age, age;
190
191 /* First decide return status as best we can */
192 if (!test_bit(CACHE_VALID, &h->flags) ||
193 h->expiry_time < get_seconds())
194 rv = -EAGAIN;
195 else if (detail->flush_time > h->last_refresh)
196 rv = -EAGAIN;
197 else {
198 /* entry is valid */
199 if (test_bit(CACHE_NEGATIVE, &h->flags))
200 rv = -ENOENT;
201 else rv = 0;
202 }
203
204 /* now see if we want to start an upcall */
205 refresh_age = (h->expiry_time - h->last_refresh);
206 age = get_seconds() - h->last_refresh;
207
208 if (rqstp == NULL) {
209 if (rv == -EAGAIN)
210 rv = -ENOENT;
211 } else if (rv == -EAGAIN || age > refresh_age/2) {
212 dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age);
213 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
214 switch (cache_make_upcall(detail, h)) {
215 case -EINVAL:
216 clear_bit(CACHE_PENDING, &h->flags);
217 if (rv == -EAGAIN) {
218 set_bit(CACHE_NEGATIVE, &h->flags);
NeilBrownebd0cb12006-03-27 01:15:08 -0800219 cache_fresh_unlocked(h, detail,
220 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 rv = -ENOENT;
222 }
223 break;
224
225 case -EAGAIN:
226 clear_bit(CACHE_PENDING, &h->flags);
227 cache_revisit_request(h);
228 break;
229 }
230 }
231 }
232
233 if (rv == -EAGAIN)
234 cache_defer_req(rqstp, h);
235
NeilBrown4013ede2006-03-27 01:15:07 -0800236 if (rv)
NeilBrownbaab9352006-03-27 01:15:09 -0800237 cache_put(h, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 return rv;
239}
240
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241/*
242 * caches need to be periodically cleaned.
243 * For this we maintain a list of cache_detail and
244 * a current pointer into that list and into the table
245 * for that entry.
246 *
247 * Each time clean_cache is called it finds the next non-empty entry
248 * in the current table and walks the list in that entry
249 * looking for entries that can be removed.
250 *
251 * An entry gets removed if:
252 * - The expiry is before current time
253 * - The last_refresh time is before the flush_time for that cache
254 *
255 * later we might drop old entries with non-NEVER expiry if that table
256 * is getting 'full' for some definition of 'full'
257 *
258 * The question of "how often to scan a table" is an interesting one
259 * and is answered in part by the use of the "nextcheck" field in the
260 * cache_detail.
261 * When a scan of a table begins, the nextcheck field is set to a time
262 * that is well into the future.
263 * While scanning, if an expiry time is found that is earlier than the
264 * current nextcheck time, nextcheck is set to that expiry time.
265 * If the flush_time is ever set to a time earlier than the nextcheck
266 * time, the nextcheck time is then set to that flush_time.
267 *
268 * A table is then only scanned if the current time is at least
269 * the nextcheck time.
270 *
271 */
272
273static LIST_HEAD(cache_list);
274static DEFINE_SPINLOCK(cache_list_lock);
275static struct cache_detail *current_detail;
276static int current_index;
277
278static struct file_operations cache_file_operations;
279static struct file_operations content_file_operations;
280static struct file_operations cache_flush_operations;
281
282static void do_cache_clean(void *data);
283static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL);
284
285void cache_register(struct cache_detail *cd)
286{
287 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
288 if (cd->proc_ent) {
289 struct proc_dir_entry *p;
Bruce Allanf35279d2005-09-06 15:17:08 -0700290 cd->proc_ent->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 cd->channel_ent = cd->content_ent = NULL;
292
293 p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR,
294 cd->proc_ent);
295 cd->flush_ent = p;
296 if (p) {
297 p->proc_fops = &cache_flush_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700298 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 p->data = cd;
300 }
301
302 if (cd->cache_request || cd->cache_parse) {
303 p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR,
304 cd->proc_ent);
305 cd->channel_ent = p;
306 if (p) {
307 p->proc_fops = &cache_file_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700308 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 p->data = cd;
310 }
311 }
312 if (cd->cache_show) {
313 p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR,
314 cd->proc_ent);
315 cd->content_ent = p;
316 if (p) {
317 p->proc_fops = &content_file_operations;
Bruce Allanf35279d2005-09-06 15:17:08 -0700318 p->owner = cd->owner;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 p->data = cd;
320 }
321 }
322 }
323 rwlock_init(&cd->hash_lock);
324 INIT_LIST_HEAD(&cd->queue);
325 spin_lock(&cache_list_lock);
326 cd->nextcheck = 0;
327 cd->entries = 0;
328 atomic_set(&cd->readers, 0);
329 cd->last_close = 0;
330 cd->last_warn = -1;
331 list_add(&cd->others, &cache_list);
332 spin_unlock(&cache_list_lock);
333
334 /* start the cleaning process */
335 schedule_work(&cache_cleaner);
336}
337
338int cache_unregister(struct cache_detail *cd)
339{
340 cache_purge(cd);
341 spin_lock(&cache_list_lock);
342 write_lock(&cd->hash_lock);
343 if (cd->entries || atomic_read(&cd->inuse)) {
344 write_unlock(&cd->hash_lock);
345 spin_unlock(&cache_list_lock);
346 return -EBUSY;
347 }
348 if (current_detail == cd)
349 current_detail = NULL;
350 list_del_init(&cd->others);
351 write_unlock(&cd->hash_lock);
352 spin_unlock(&cache_list_lock);
353 if (cd->proc_ent) {
354 if (cd->flush_ent)
355 remove_proc_entry("flush", cd->proc_ent);
356 if (cd->channel_ent)
357 remove_proc_entry("channel", cd->proc_ent);
358 if (cd->content_ent)
359 remove_proc_entry("content", cd->proc_ent);
360
361 cd->proc_ent = NULL;
362 remove_proc_entry(cd->name, proc_net_rpc);
363 }
364 if (list_empty(&cache_list)) {
365 /* module must be being unloaded so its safe to kill the worker */
366 cancel_delayed_work(&cache_cleaner);
367 flush_scheduled_work();
368 }
369 return 0;
370}
371
372/* clean cache tries to find something to clean
373 * and cleans it.
374 * It returns 1 if it cleaned something,
375 * 0 if it didn't find anything this time
376 * -1 if it fell off the end of the list.
377 */
378static int cache_clean(void)
379{
380 int rv = 0;
381 struct list_head *next;
382
383 spin_lock(&cache_list_lock);
384
385 /* find a suitable table if we don't already have one */
386 while (current_detail == NULL ||
387 current_index >= current_detail->hash_size) {
388 if (current_detail)
389 next = current_detail->others.next;
390 else
391 next = cache_list.next;
392 if (next == &cache_list) {
393 current_detail = NULL;
394 spin_unlock(&cache_list_lock);
395 return -1;
396 }
397 current_detail = list_entry(next, struct cache_detail, others);
398 if (current_detail->nextcheck > get_seconds())
399 current_index = current_detail->hash_size;
400 else {
401 current_index = 0;
402 current_detail->nextcheck = get_seconds()+30*60;
403 }
404 }
405
406 /* find a non-empty bucket in the table */
407 while (current_detail &&
408 current_index < current_detail->hash_size &&
409 current_detail->hash_table[current_index] == NULL)
410 current_index++;
411
412 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
413
414 if (current_detail && current_index < current_detail->hash_size) {
415 struct cache_head *ch, **cp;
416 struct cache_detail *d;
417
418 write_lock(&current_detail->hash_lock);
419
420 /* Ok, now to clean this strand */
421
422 cp = & current_detail->hash_table[current_index];
423 ch = *cp;
424 for (; ch; cp= & ch->next, ch= *cp) {
425 if (current_detail->nextcheck > ch->expiry_time)
426 current_detail->nextcheck = ch->expiry_time+1;
427 if (ch->expiry_time >= get_seconds()
428 && ch->last_refresh >= current_detail->flush_time
429 )
430 continue;
431 if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
432 queue_loose(current_detail, ch);
433
NeilBrownbaab9352006-03-27 01:15:09 -0800434 if (atomic_read(&ch->ref.refcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 break;
436 }
437 if (ch) {
438 *cp = ch->next;
439 ch->next = NULL;
440 current_detail->entries--;
441 rv = 1;
442 }
443 write_unlock(&current_detail->hash_lock);
444 d = current_detail;
445 if (!ch)
446 current_index ++;
447 spin_unlock(&cache_list_lock);
448 if (ch)
NeilBrownbaab9352006-03-27 01:15:09 -0800449 cache_put(ch, d);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 } else
451 spin_unlock(&cache_list_lock);
452
453 return rv;
454}
455
456/*
457 * We want to regularly clean the cache, so we need to schedule some work ...
458 */
459static void do_cache_clean(void *data)
460{
461 int delay = 5;
462 if (cache_clean() == -1)
463 delay = 30*HZ;
464
465 if (list_empty(&cache_list))
466 delay = 0;
467
468 if (delay)
469 schedule_delayed_work(&cache_cleaner, delay);
470}
471
472
473/*
474 * Clean all caches promptly. This just calls cache_clean
475 * repeatedly until we are sure that every cache has had a chance to
476 * be fully cleaned
477 */
478void cache_flush(void)
479{
480 while (cache_clean() != -1)
481 cond_resched();
482 while (cache_clean() != -1)
483 cond_resched();
484}
485
486void cache_purge(struct cache_detail *detail)
487{
488 detail->flush_time = LONG_MAX;
489 detail->nextcheck = get_seconds();
490 cache_flush();
491 detail->flush_time = 1;
492}
493
494
495
496/*
497 * Deferral and Revisiting of Requests.
498 *
499 * If a cache lookup finds a pending entry, we
500 * need to defer the request and revisit it later.
501 * All deferred requests are stored in a hash table,
502 * indexed by "struct cache_head *".
503 * As it may be wasteful to store a whole request
504 * structure, we allow the request to provide a
505 * deferred form, which must contain a
506 * 'struct cache_deferred_req'
507 * This cache_deferred_req contains a method to allow
508 * it to be revisited when cache info is available
509 */
510
511#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
512#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
513
514#define DFR_MAX 300 /* ??? */
515
516static DEFINE_SPINLOCK(cache_defer_lock);
517static LIST_HEAD(cache_defer_list);
518static struct list_head cache_defer_hash[DFR_HASHSIZE];
519static int cache_defer_cnt;
520
521static void cache_defer_req(struct cache_req *req, struct cache_head *item)
522{
523 struct cache_deferred_req *dreq;
524 int hash = DFR_HASH(item);
525
526 dreq = req->defer(req);
527 if (dreq == NULL)
528 return;
529
530 dreq->item = item;
531 dreq->recv_time = get_seconds();
532
533 spin_lock(&cache_defer_lock);
534
535 list_add(&dreq->recent, &cache_defer_list);
536
537 if (cache_defer_hash[hash].next == NULL)
538 INIT_LIST_HEAD(&cache_defer_hash[hash]);
539 list_add(&dreq->hash, &cache_defer_hash[hash]);
540
541 /* it is in, now maybe clean up */
542 dreq = NULL;
543 if (++cache_defer_cnt > DFR_MAX) {
544 /* too much in the cache, randomly drop
545 * first or last
546 */
547 if (net_random()&1)
548 dreq = list_entry(cache_defer_list.next,
549 struct cache_deferred_req,
550 recent);
551 else
552 dreq = list_entry(cache_defer_list.prev,
553 struct cache_deferred_req,
554 recent);
555 list_del(&dreq->recent);
556 list_del(&dreq->hash);
557 cache_defer_cnt--;
558 }
559 spin_unlock(&cache_defer_lock);
560
561 if (dreq) {
562 /* there was one too many */
563 dreq->revisit(dreq, 1);
564 }
NeilBrown4013ede2006-03-27 01:15:07 -0800565 if (!test_bit(CACHE_PENDING, &item->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 /* must have just been validated... */
567 cache_revisit_request(item);
568 }
569}
570
571static void cache_revisit_request(struct cache_head *item)
572{
573 struct cache_deferred_req *dreq;
574 struct list_head pending;
575
576 struct list_head *lp;
577 int hash = DFR_HASH(item);
578
579 INIT_LIST_HEAD(&pending);
580 spin_lock(&cache_defer_lock);
581
582 lp = cache_defer_hash[hash].next;
583 if (lp) {
584 while (lp != &cache_defer_hash[hash]) {
585 dreq = list_entry(lp, struct cache_deferred_req, hash);
586 lp = lp->next;
587 if (dreq->item == item) {
588 list_del(&dreq->hash);
589 list_move(&dreq->recent, &pending);
590 cache_defer_cnt--;
591 }
592 }
593 }
594 spin_unlock(&cache_defer_lock);
595
596 while (!list_empty(&pending)) {
597 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
598 list_del_init(&dreq->recent);
599 dreq->revisit(dreq, 0);
600 }
601}
602
603void cache_clean_deferred(void *owner)
604{
605 struct cache_deferred_req *dreq, *tmp;
606 struct list_head pending;
607
608
609 INIT_LIST_HEAD(&pending);
610 spin_lock(&cache_defer_lock);
611
612 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
613 if (dreq->owner == owner) {
614 list_del(&dreq->hash);
615 list_move(&dreq->recent, &pending);
616 cache_defer_cnt--;
617 }
618 }
619 spin_unlock(&cache_defer_lock);
620
621 while (!list_empty(&pending)) {
622 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
623 list_del_init(&dreq->recent);
624 dreq->revisit(dreq, 1);
625 }
626}
627
628/*
629 * communicate with user-space
630 *
631 * We have a magic /proc file - /proc/sunrpc/cache
632 * On read, you get a full request, or block
633 * On write, an update request is processed
634 * Poll works if anything to read, and always allows write
635 *
636 * Implemented by linked list of requests. Each open file has
637 * a ->private that also exists in this list. New request are added
638 * to the end and may wakeup and preceding readers.
639 * New readers are added to the head. If, on read, an item is found with
640 * CACHE_UPCALLING clear, we free it from the list.
641 *
642 */
643
644static DEFINE_SPINLOCK(queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800645static DEFINE_MUTEX(queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646
647struct cache_queue {
648 struct list_head list;
649 int reader; /* if 0, then request */
650};
651struct cache_request {
652 struct cache_queue q;
653 struct cache_head *item;
654 char * buf;
655 int len;
656 int readers;
657};
658struct cache_reader {
659 struct cache_queue q;
660 int offset; /* if non-0, we have a refcnt on next request */
661};
662
663static ssize_t
664cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
665{
666 struct cache_reader *rp = filp->private_data;
667 struct cache_request *rq;
668 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
669 int err;
670
671 if (count == 0)
672 return 0;
673
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800674 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 * readers on this file */
676 again:
677 spin_lock(&queue_lock);
678 /* need to find next request */
679 while (rp->q.list.next != &cd->queue &&
680 list_entry(rp->q.list.next, struct cache_queue, list)
681 ->reader) {
682 struct list_head *next = rp->q.list.next;
683 list_move(&rp->q.list, next);
684 }
685 if (rp->q.list.next == &cd->queue) {
686 spin_unlock(&queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800687 mutex_unlock(&queue_io_mutex);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800688 BUG_ON(rp->offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 return 0;
690 }
691 rq = container_of(rp->q.list.next, struct cache_request, q.list);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800692 BUG_ON(rq->q.reader);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 if (rp->offset == 0)
694 rq->readers++;
695 spin_unlock(&queue_lock);
696
697 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
698 err = -EAGAIN;
699 spin_lock(&queue_lock);
700 list_move(&rp->q.list, &rq->q.list);
701 spin_unlock(&queue_lock);
702 } else {
703 if (rp->offset + count > rq->len)
704 count = rq->len - rp->offset;
705 err = -EFAULT;
706 if (copy_to_user(buf, rq->buf + rp->offset, count))
707 goto out;
708 rp->offset += count;
709 if (rp->offset >= rq->len) {
710 rp->offset = 0;
711 spin_lock(&queue_lock);
712 list_move(&rp->q.list, &rq->q.list);
713 spin_unlock(&queue_lock);
714 }
715 err = 0;
716 }
717 out:
718 if (rp->offset == 0) {
719 /* need to release rq */
720 spin_lock(&queue_lock);
721 rq->readers--;
722 if (rq->readers == 0 &&
723 !test_bit(CACHE_PENDING, &rq->item->flags)) {
724 list_del(&rq->q.list);
725 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800726 cache_put(rq->item, cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 kfree(rq->buf);
728 kfree(rq);
729 } else
730 spin_unlock(&queue_lock);
731 }
732 if (err == -EAGAIN)
733 goto again;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800734 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 return err ? err : count;
736}
737
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800738static char write_buf[8192]; /* protected by queue_io_mutex */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739
740static ssize_t
741cache_write(struct file *filp, const char __user *buf, size_t count,
742 loff_t *ppos)
743{
744 int err;
745 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
746
747 if (count == 0)
748 return 0;
749 if (count >= sizeof(write_buf))
750 return -EINVAL;
751
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800752 mutex_lock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753
754 if (copy_from_user(write_buf, buf, count)) {
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800755 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 return -EFAULT;
757 }
758 write_buf[count] = '\0';
759 if (cd->cache_parse)
760 err = cd->cache_parse(cd, write_buf, count);
761 else
762 err = -EINVAL;
763
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800764 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 return err ? err : count;
766}
767
768static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
769
770static unsigned int
771cache_poll(struct file *filp, poll_table *wait)
772{
773 unsigned int mask;
774 struct cache_reader *rp = filp->private_data;
775 struct cache_queue *cq;
776 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data;
777
778 poll_wait(filp, &queue_wait, wait);
779
780 /* alway allow write */
781 mask = POLL_OUT | POLLWRNORM;
782
783 if (!rp)
784 return mask;
785
786 spin_lock(&queue_lock);
787
788 for (cq= &rp->q; &cq->list != &cd->queue;
789 cq = list_entry(cq->list.next, struct cache_queue, list))
790 if (!cq->reader) {
791 mask |= POLLIN | POLLRDNORM;
792 break;
793 }
794 spin_unlock(&queue_lock);
795 return mask;
796}
797
798static int
799cache_ioctl(struct inode *ino, struct file *filp,
800 unsigned int cmd, unsigned long arg)
801{
802 int len = 0;
803 struct cache_reader *rp = filp->private_data;
804 struct cache_queue *cq;
805 struct cache_detail *cd = PDE(ino)->data;
806
807 if (cmd != FIONREAD || !rp)
808 return -EINVAL;
809
810 spin_lock(&queue_lock);
811
812 /* only find the length remaining in current request,
813 * or the length of the next request
814 */
815 for (cq= &rp->q; &cq->list != &cd->queue;
816 cq = list_entry(cq->list.next, struct cache_queue, list))
817 if (!cq->reader) {
818 struct cache_request *cr =
819 container_of(cq, struct cache_request, q);
820 len = cr->len - rp->offset;
821 break;
822 }
823 spin_unlock(&queue_lock);
824
825 return put_user(len, (int __user *)arg);
826}
827
828static int
829cache_open(struct inode *inode, struct file *filp)
830{
831 struct cache_reader *rp = NULL;
832
833 nonseekable_open(inode, filp);
834 if (filp->f_mode & FMODE_READ) {
835 struct cache_detail *cd = PDE(inode)->data;
836
837 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
838 if (!rp)
839 return -ENOMEM;
840 rp->offset = 0;
841 rp->q.reader = 1;
842 atomic_inc(&cd->readers);
843 spin_lock(&queue_lock);
844 list_add(&rp->q.list, &cd->queue);
845 spin_unlock(&queue_lock);
846 }
847 filp->private_data = rp;
848 return 0;
849}
850
851static int
852cache_release(struct inode *inode, struct file *filp)
853{
854 struct cache_reader *rp = filp->private_data;
855 struct cache_detail *cd = PDE(inode)->data;
856
857 if (rp) {
858 spin_lock(&queue_lock);
859 if (rp->offset) {
860 struct cache_queue *cq;
861 for (cq= &rp->q; &cq->list != &cd->queue;
862 cq = list_entry(cq->list.next, struct cache_queue, list))
863 if (!cq->reader) {
864 container_of(cq, struct cache_request, q)
865 ->readers--;
866 break;
867 }
868 rp->offset = 0;
869 }
870 list_del(&rp->q.list);
871 spin_unlock(&queue_lock);
872
873 filp->private_data = NULL;
874 kfree(rp);
875
876 cd->last_close = get_seconds();
877 atomic_dec(&cd->readers);
878 }
879 return 0;
880}
881
882
883
884static struct file_operations cache_file_operations = {
885 .owner = THIS_MODULE,
886 .llseek = no_llseek,
887 .read = cache_read,
888 .write = cache_write,
889 .poll = cache_poll,
890 .ioctl = cache_ioctl, /* for FIONREAD */
891 .open = cache_open,
892 .release = cache_release,
893};
894
895
896static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
897{
898 struct cache_queue *cq;
899 spin_lock(&queue_lock);
900 list_for_each_entry(cq, &detail->queue, list)
901 if (!cq->reader) {
902 struct cache_request *cr = container_of(cq, struct cache_request, q);
903 if (cr->item != ch)
904 continue;
905 if (cr->readers != 0)
NeilBrown4013ede2006-03-27 01:15:07 -0800906 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 list_del(&cr->q.list);
908 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800909 cache_put(cr->item, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 kfree(cr->buf);
911 kfree(cr);
912 return;
913 }
914 spin_unlock(&queue_lock);
915}
916
917/*
918 * Support routines for text-based upcalls.
919 * Fields are separated by spaces.
920 * Fields are either mangled to quote space tab newline slosh with slosh
921 * or a hexified with a leading \x
922 * Record is terminated with newline.
923 *
924 */
925
926void qword_add(char **bpp, int *lp, char *str)
927{
928 char *bp = *bpp;
929 int len = *lp;
930 char c;
931
932 if (len < 0) return;
933
934 while ((c=*str++) && len)
935 switch(c) {
936 case ' ':
937 case '\t':
938 case '\n':
939 case '\\':
940 if (len >= 4) {
941 *bp++ = '\\';
942 *bp++ = '0' + ((c & 0300)>>6);
943 *bp++ = '0' + ((c & 0070)>>3);
944 *bp++ = '0' + ((c & 0007)>>0);
945 }
946 len -= 4;
947 break;
948 default:
949 *bp++ = c;
950 len--;
951 }
952 if (c || len <1) len = -1;
953 else {
954 *bp++ = ' ';
955 len--;
956 }
957 *bpp = bp;
958 *lp = len;
959}
960
961void qword_addhex(char **bpp, int *lp, char *buf, int blen)
962{
963 char *bp = *bpp;
964 int len = *lp;
965
966 if (len < 0) return;
967
968 if (len > 2) {
969 *bp++ = '\\';
970 *bp++ = 'x';
971 len -= 2;
972 while (blen && len >= 2) {
973 unsigned char c = *buf++;
974 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
975 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
976 len -= 2;
977 blen--;
978 }
979 }
980 if (blen || len<1) len = -1;
981 else {
982 *bp++ = ' ';
983 len--;
984 }
985 *bpp = bp;
986 *lp = len;
987}
988
989static void warn_no_listener(struct cache_detail *detail)
990{
991 if (detail->last_warn != detail->last_close) {
992 detail->last_warn = detail->last_close;
993 if (detail->warn_no_listener)
994 detail->warn_no_listener(detail);
995 }
996}
997
998/*
999 * register an upcall request to user-space.
1000 * Each request is at most one page long.
1001 */
1002static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h)
1003{
1004
1005 char *buf;
1006 struct cache_request *crq;
1007 char *bp;
1008 int len;
1009
1010 if (detail->cache_request == NULL)
1011 return -EINVAL;
1012
1013 if (atomic_read(&detail->readers) == 0 &&
1014 detail->last_close < get_seconds() - 30) {
1015 warn_no_listener(detail);
1016 return -EINVAL;
1017 }
1018
1019 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1020 if (!buf)
1021 return -EAGAIN;
1022
1023 crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1024 if (!crq) {
1025 kfree(buf);
1026 return -EAGAIN;
1027 }
1028
1029 bp = buf; len = PAGE_SIZE;
1030
1031 detail->cache_request(detail, h, &bp, &len);
1032
1033 if (len < 0) {
1034 kfree(buf);
1035 kfree(crq);
1036 return -EAGAIN;
1037 }
1038 crq->q.reader = 0;
1039 crq->item = cache_get(h);
1040 crq->buf = buf;
1041 crq->len = PAGE_SIZE - len;
1042 crq->readers = 0;
1043 spin_lock(&queue_lock);
1044 list_add_tail(&crq->q.list, &detail->queue);
1045 spin_unlock(&queue_lock);
1046 wake_up(&queue_wait);
1047 return 0;
1048}
1049
1050/*
1051 * parse a message from user-space and pass it
1052 * to an appropriate cache
1053 * Messages are, like requests, separated into fields by
1054 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1055 *
1056 * Message is
1057 * reply cachename expiry key ... content....
1058 *
1059 * key and content are both parsed by cache
1060 */
1061
1062#define isodigit(c) (isdigit(c) && c <= '7')
1063int qword_get(char **bpp, char *dest, int bufsize)
1064{
1065 /* return bytes copied, or -1 on error */
1066 char *bp = *bpp;
1067 int len = 0;
1068
1069 while (*bp == ' ') bp++;
1070
1071 if (bp[0] == '\\' && bp[1] == 'x') {
1072 /* HEX STRING */
1073 bp += 2;
1074 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) {
1075 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1076 bp++;
1077 byte <<= 4;
1078 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10;
1079 *dest++ = byte;
1080 bp++;
1081 len++;
1082 }
1083 } else {
1084 /* text with \nnn octal quoting */
1085 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1086 if (*bp == '\\' &&
1087 isodigit(bp[1]) && (bp[1] <= '3') &&
1088 isodigit(bp[2]) &&
1089 isodigit(bp[3])) {
1090 int byte = (*++bp -'0');
1091 bp++;
1092 byte = (byte << 3) | (*bp++ - '0');
1093 byte = (byte << 3) | (*bp++ - '0');
1094 *dest++ = byte;
1095 len++;
1096 } else {
1097 *dest++ = *bp++;
1098 len++;
1099 }
1100 }
1101 }
1102
1103 if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1104 return -1;
1105 while (*bp == ' ') bp++;
1106 *bpp = bp;
1107 *dest = '\0';
1108 return len;
1109}
1110
1111
1112/*
1113 * support /proc/sunrpc/cache/$CACHENAME/content
1114 * as a seqfile.
1115 * We call ->cache_show passing NULL for the item to
1116 * get a header, then pass each real item in the cache
1117 */
1118
1119struct handle {
1120 struct cache_detail *cd;
1121};
1122
1123static void *c_start(struct seq_file *m, loff_t *pos)
1124{
1125 loff_t n = *pos;
1126 unsigned hash, entry;
1127 struct cache_head *ch;
1128 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1129
1130
1131 read_lock(&cd->hash_lock);
1132 if (!n--)
1133 return SEQ_START_TOKEN;
1134 hash = n >> 32;
1135 entry = n & ((1LL<<32) - 1);
1136
1137 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1138 if (!entry--)
1139 return ch;
1140 n &= ~((1LL<<32) - 1);
1141 do {
1142 hash++;
1143 n += 1LL<<32;
1144 } while(hash < cd->hash_size &&
1145 cd->hash_table[hash]==NULL);
1146 if (hash >= cd->hash_size)
1147 return NULL;
1148 *pos = n+1;
1149 return cd->hash_table[hash];
1150}
1151
1152static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1153{
1154 struct cache_head *ch = p;
1155 int hash = (*pos >> 32);
1156 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1157
1158 if (p == SEQ_START_TOKEN)
1159 hash = 0;
1160 else if (ch->next == NULL) {
1161 hash++;
1162 *pos += 1LL<<32;
1163 } else {
1164 ++*pos;
1165 return ch->next;
1166 }
1167 *pos &= ~((1LL<<32) - 1);
1168 while (hash < cd->hash_size &&
1169 cd->hash_table[hash] == NULL) {
1170 hash++;
1171 *pos += 1LL<<32;
1172 }
1173 if (hash >= cd->hash_size)
1174 return NULL;
1175 ++*pos;
1176 return cd->hash_table[hash];
1177}
1178
1179static void c_stop(struct seq_file *m, void *p)
1180{
1181 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1182 read_unlock(&cd->hash_lock);
1183}
1184
1185static int c_show(struct seq_file *m, void *p)
1186{
1187 struct cache_head *cp = p;
1188 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1189
1190 if (p == SEQ_START_TOKEN)
1191 return cd->cache_show(m, cd, NULL);
1192
1193 ifdebug(CACHE)
NeilBrown4013ede2006-03-27 01:15:07 -08001194 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
NeilBrownbaab9352006-03-27 01:15:09 -08001195 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 cache_get(cp);
1197 if (cache_check(cd, cp, NULL))
1198 /* cache_check does a cache_put on failure */
1199 seq_printf(m, "# ");
1200 else
1201 cache_put(cp, cd);
1202
1203 return cd->cache_show(m, cd, cp);
1204}
1205
1206static struct seq_operations cache_content_op = {
1207 .start = c_start,
1208 .next = c_next,
1209 .stop = c_stop,
1210 .show = c_show,
1211};
1212
1213static int content_open(struct inode *inode, struct file *file)
1214{
1215 int res;
1216 struct handle *han;
1217 struct cache_detail *cd = PDE(inode)->data;
1218
1219 han = kmalloc(sizeof(*han), GFP_KERNEL);
1220 if (han == NULL)
1221 return -ENOMEM;
1222
1223 han->cd = cd;
1224
1225 res = seq_open(file, &cache_content_op);
1226 if (res)
1227 kfree(han);
1228 else
1229 ((struct seq_file *)file->private_data)->private = han;
1230
1231 return res;
1232}
1233static int content_release(struct inode *inode, struct file *file)
1234{
1235 struct seq_file *m = (struct seq_file *)file->private_data;
1236 struct handle *han = m->private;
1237 kfree(han);
1238 m->private = NULL;
1239 return seq_release(inode, file);
1240}
1241
1242static struct file_operations content_file_operations = {
1243 .open = content_open,
1244 .read = seq_read,
1245 .llseek = seq_lseek,
1246 .release = content_release,
1247};
1248
1249static ssize_t read_flush(struct file *file, char __user *buf,
1250 size_t count, loff_t *ppos)
1251{
1252 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1253 char tbuf[20];
1254 unsigned long p = *ppos;
1255 int len;
1256
1257 sprintf(tbuf, "%lu\n", cd->flush_time);
1258 len = strlen(tbuf);
1259 if (p >= len)
1260 return 0;
1261 len -= p;
1262 if (len > count) len = count;
1263 if (copy_to_user(buf, (void*)(tbuf+p), len))
1264 len = -EFAULT;
1265 else
1266 *ppos += len;
1267 return len;
1268}
1269
1270static ssize_t write_flush(struct file * file, const char __user * buf,
1271 size_t count, loff_t *ppos)
1272{
1273 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data;
1274 char tbuf[20];
1275 char *ep;
1276 long flushtime;
1277 if (*ppos || count > sizeof(tbuf)-1)
1278 return -EINVAL;
1279 if (copy_from_user(tbuf, buf, count))
1280 return -EFAULT;
1281 tbuf[count] = 0;
1282 flushtime = simple_strtoul(tbuf, &ep, 0);
1283 if (*ep && *ep != '\n')
1284 return -EINVAL;
1285
1286 cd->flush_time = flushtime;
1287 cd->nextcheck = get_seconds();
1288 cache_flush();
1289
1290 *ppos += count;
1291 return count;
1292}
1293
1294static struct file_operations cache_flush_operations = {
1295 .open = nonseekable_open,
1296 .read = read_flush,
1297 .write = write_flush,
1298};