Commit | Line | Data |
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1da177e4 LT |
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> | |
4a3e2f71 | 29 | #include <linux/mutex.h> |
1da177e4 LT |
30 | #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 | ||
37 | static void cache_defer_req(struct cache_req *req, struct cache_head *item); | |
38 | static void cache_revisit_request(struct cache_head *item); | |
39 | ||
74cae61a | 40 | static void cache_init(struct cache_head *h) |
1da177e4 LT |
41 | { |
42 | time_t now = get_seconds(); | |
43 | h->next = NULL; | |
44 | h->flags = 0; | |
baab935f | 45 | kref_init(&h->ref); |
1da177e4 LT |
46 | h->expiry_time = now + CACHE_NEW_EXPIRY; |
47 | h->last_refresh = now; | |
48 | } | |
49 | ||
15a5f6bd N |
50 | struct 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); | |
baab935f | 84 | cache_put(new, detail); |
15a5f6bd N |
85 | 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 | } | |
97 | EXPORT_SYMBOL(sunrpc_cache_lookup); | |
98 | ||
ebd0cb1a N |
99 | |
100 | static void queue_loose(struct cache_detail *detail, struct cache_head *ch); | |
101 | ||
102 | static 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 | ||
109 | static 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 | ||
15a5f6bd N |
120 | struct 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; | |
ebd0cb1a | 129 | int is_new; |
15a5f6bd N |
130 | |
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); | |
ebd0cb1a | 138 | is_new = cache_fresh_locked(old, new->expiry_time); |
15a5f6bd | 139 | write_unlock(&detail->hash_lock); |
ebd0cb1a | 140 | cache_fresh_unlocked(old, detail, is_new); |
15a5f6bd N |
141 | 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) { | |
baab935f | 148 | cache_put(old, detail); |
15a5f6bd N |
149 | 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); | |
ebd0cb1a N |
163 | is_new = cache_fresh_locked(tmp, new->expiry_time); |
164 | cache_fresh_locked(old, 0); | |
15a5f6bd | 165 | write_unlock(&detail->hash_lock); |
ebd0cb1a N |
166 | cache_fresh_unlocked(tmp, detail, is_new); |
167 | cache_fresh_unlocked(old, detail, 0); | |
baab935f | 168 | cache_put(old, detail); |
15a5f6bd N |
169 | return tmp; |
170 | } | |
171 | EXPORT_SYMBOL(sunrpc_cache_update); | |
1da177e4 LT |
172 | |
173 | static 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 | */ | |
185 | int 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); | |
ebd0cb1a N |
219 | cache_fresh_unlocked(h, detail, |
220 | cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); | |
1da177e4 LT |
221 | 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 | ||
4013edea | 236 | if (rv) |
baab935f | 237 | cache_put(h, detail); |
1da177e4 LT |
238 | return rv; |
239 | } | |
240 | ||
1da177e4 LT |
241 | /* |
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 | ||
273 | static LIST_HEAD(cache_list); | |
274 | static DEFINE_SPINLOCK(cache_list_lock); | |
275 | static struct cache_detail *current_detail; | |
276 | static int current_index; | |
277 | ||
278 | static struct file_operations cache_file_operations; | |
279 | static struct file_operations content_file_operations; | |
280 | static struct file_operations cache_flush_operations; | |
281 | ||
282 | static void do_cache_clean(void *data); | |
283 | static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL); | |
284 | ||
285 | void 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; | |
f35279d3 | 290 | cd->proc_ent->owner = cd->owner; |
1da177e4 LT |
291 | 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; | |
f35279d3 | 298 | p->owner = cd->owner; |
1da177e4 LT |
299 | 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; | |
f35279d3 | 308 | p->owner = cd->owner; |
1da177e4 LT |
309 | 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; | |
f35279d3 | 318 | p->owner = cd->owner; |
1da177e4 LT |
319 | 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 | ||
338 | int 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 | */ | |
378 | static 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(¤t_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 | ||
baab935f | 434 | if (atomic_read(&ch->ref.refcount) == 1) |
1da177e4 LT |
435 | break; |
436 | } | |
437 | if (ch) { | |
438 | *cp = ch->next; | |
439 | ch->next = NULL; | |
440 | current_detail->entries--; | |
441 | rv = 1; | |
442 | } | |
443 | write_unlock(¤t_detail->hash_lock); | |
444 | d = current_detail; | |
445 | if (!ch) | |
446 | current_index ++; | |
447 | spin_unlock(&cache_list_lock); | |
448 | if (ch) | |
baab935f | 449 | cache_put(ch, d); |
1da177e4 LT |
450 | } 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 | */ | |
459 | static 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 | */ | |
478 | void cache_flush(void) | |
479 | { | |
480 | while (cache_clean() != -1) | |
481 | cond_resched(); | |
482 | while (cache_clean() != -1) | |
483 | cond_resched(); | |
484 | } | |
485 | ||
486 | void 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 | ||
516 | static DEFINE_SPINLOCK(cache_defer_lock); | |
517 | static LIST_HEAD(cache_defer_list); | |
518 | static struct list_head cache_defer_hash[DFR_HASHSIZE]; | |
519 | static int cache_defer_cnt; | |
520 | ||
521 | static 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 | } | |
4013edea | 565 | if (!test_bit(CACHE_PENDING, &item->flags)) { |
1da177e4 LT |
566 | /* must have just been validated... */ |
567 | cache_revisit_request(item); | |
568 | } | |
569 | } | |
570 | ||
571 | static 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 | ||
603 | void 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 | ||
644 | static DEFINE_SPINLOCK(queue_lock); | |
4a3e2f71 | 645 | static DEFINE_MUTEX(queue_io_mutex); |
1da177e4 LT |
646 | |
647 | struct cache_queue { | |
648 | struct list_head list; | |
649 | int reader; /* if 0, then request */ | |
650 | }; | |
651 | struct cache_request { | |
652 | struct cache_queue q; | |
653 | struct cache_head *item; | |
654 | char * buf; | |
655 | int len; | |
656 | int readers; | |
657 | }; | |
658 | struct cache_reader { | |
659 | struct cache_queue q; | |
660 | int offset; /* if non-0, we have a refcnt on next request */ | |
661 | }; | |
662 | ||
663 | static ssize_t | |
664 | cache_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 | ||
4a3e2f71 | 674 | mutex_lock(&queue_io_mutex); /* protect against multiple concurrent |
1da177e4 LT |
675 | * 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); | |
4a3e2f71 | 687 | mutex_unlock(&queue_io_mutex); |
09a62660 | 688 | BUG_ON(rp->offset); |
1da177e4 LT |
689 | return 0; |
690 | } | |
691 | rq = container_of(rp->q.list.next, struct cache_request, q.list); | |
09a62660 | 692 | BUG_ON(rq->q.reader); |
1da177e4 LT |
693 | 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); | |
baab935f | 726 | cache_put(rq->item, cd); |
1da177e4 LT |
727 | kfree(rq->buf); |
728 | kfree(rq); | |
729 | } else | |
730 | spin_unlock(&queue_lock); | |
731 | } | |
732 | if (err == -EAGAIN) | |
733 | goto again; | |
4a3e2f71 | 734 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
735 | return err ? err : count; |
736 | } | |
737 | ||
4a3e2f71 | 738 | static char write_buf[8192]; /* protected by queue_io_mutex */ |
1da177e4 LT |
739 | |
740 | static ssize_t | |
741 | cache_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 | ||
4a3e2f71 | 752 | mutex_lock(&queue_io_mutex); |
1da177e4 LT |
753 | |
754 | if (copy_from_user(write_buf, buf, count)) { | |
4a3e2f71 | 755 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
756 | 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 | ||
4a3e2f71 | 764 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
765 | return err ? err : count; |
766 | } | |
767 | ||
768 | static DECLARE_WAIT_QUEUE_HEAD(queue_wait); | |
769 | ||
770 | static unsigned int | |
771 | cache_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 | ||
798 | static int | |
799 | cache_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 | ||
828 | static int | |
829 | cache_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 | ||
851 | static int | |
852 | cache_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 | ||
884 | static 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 | ||
896 | static 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) | |
4013edea | 906 | continue; |
1da177e4 LT |
907 | list_del(&cr->q.list); |
908 | spin_unlock(&queue_lock); | |
baab935f | 909 | cache_put(cr->item, detail); |
1da177e4 LT |
910 | 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 | ||
926 | void 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 | ||
961 | void 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 | ||
989 | static 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 | */ | |
1002 | static 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') | |
1063 | int 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 | ||
1119 | struct handle { | |
1120 | struct cache_detail *cd; | |
1121 | }; | |
1122 | ||
1123 | static 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 | ||
1152 | static 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 | ||
1179 | static 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 | ||
1185 | static 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) | |
4013edea | 1194 | seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", |
baab935f | 1195 | cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); |
1da177e4 LT |
1196 | 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 | ||
1206 | static struct seq_operations cache_content_op = { | |
1207 | .start = c_start, | |
1208 | .next = c_next, | |
1209 | .stop = c_stop, | |
1210 | .show = c_show, | |
1211 | }; | |
1212 | ||
1213 | static 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 | } | |
1233 | static 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 | ||
1242 | static struct file_operations content_file_operations = { | |
1243 | .open = content_open, | |
1244 | .read = seq_read, | |
1245 | .llseek = seq_lseek, | |
1246 | .release = content_release, | |
1247 | }; | |
1248 | ||
1249 | static 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 | ||
1270 | static 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 | ||
1294 | static struct file_operations cache_flush_operations = { | |
1295 | .open = nonseekable_open, | |
1296 | .read = read_flush, | |
1297 | .write = write_flush, | |
1298 | }; |