Commit | Line | Data |
---|---|---|
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 | ||
e0bb89ef | 37 | static int cache_defer_req(struct cache_req *req, struct cache_head *item); |
1da177e4 LT |
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; | |
2f34931f NB |
74 | /* must fully initialise 'new', else |
75 | * we might get lose if we need to | |
76 | * cache_put it soon. | |
77 | */ | |
15a5f6bd | 78 | cache_init(new); |
2f34931f | 79 | detail->init(new, key); |
15a5f6bd N |
80 | |
81 | write_lock(&detail->hash_lock); | |
82 | ||
83 | /* check if entry appeared while we slept */ | |
84 | for (hp=head; *hp != NULL ; hp = &(*hp)->next) { | |
85 | struct cache_head *tmp = *hp; | |
86 | if (detail->match(tmp, key)) { | |
87 | cache_get(tmp); | |
88 | write_unlock(&detail->hash_lock); | |
baab935f | 89 | cache_put(new, detail); |
15a5f6bd N |
90 | return tmp; |
91 | } | |
92 | } | |
15a5f6bd N |
93 | new->next = *head; |
94 | *head = new; | |
95 | detail->entries++; | |
96 | cache_get(new); | |
97 | write_unlock(&detail->hash_lock); | |
98 | ||
99 | return new; | |
100 | } | |
101 | EXPORT_SYMBOL(sunrpc_cache_lookup); | |
102 | ||
ebd0cb1a N |
103 | |
104 | static void queue_loose(struct cache_detail *detail, struct cache_head *ch); | |
105 | ||
106 | static int cache_fresh_locked(struct cache_head *head, time_t expiry) | |
107 | { | |
108 | head->expiry_time = expiry; | |
109 | head->last_refresh = get_seconds(); | |
110 | return !test_and_set_bit(CACHE_VALID, &head->flags); | |
111 | } | |
112 | ||
113 | static void cache_fresh_unlocked(struct cache_head *head, | |
114 | struct cache_detail *detail, int new) | |
115 | { | |
116 | if (new) | |
117 | cache_revisit_request(head); | |
118 | if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { | |
119 | cache_revisit_request(head); | |
120 | queue_loose(detail, head); | |
121 | } | |
122 | } | |
123 | ||
15a5f6bd N |
124 | struct cache_head *sunrpc_cache_update(struct cache_detail *detail, |
125 | struct cache_head *new, struct cache_head *old, int hash) | |
126 | { | |
127 | /* The 'old' entry is to be replaced by 'new'. | |
128 | * If 'old' is not VALID, we update it directly, | |
129 | * otherwise we need to replace it | |
130 | */ | |
131 | struct cache_head **head; | |
132 | struct cache_head *tmp; | |
ebd0cb1a | 133 | int is_new; |
15a5f6bd N |
134 | |
135 | if (!test_bit(CACHE_VALID, &old->flags)) { | |
136 | write_lock(&detail->hash_lock); | |
137 | if (!test_bit(CACHE_VALID, &old->flags)) { | |
138 | if (test_bit(CACHE_NEGATIVE, &new->flags)) | |
139 | set_bit(CACHE_NEGATIVE, &old->flags); | |
140 | else | |
141 | detail->update(old, new); | |
ebd0cb1a | 142 | is_new = cache_fresh_locked(old, new->expiry_time); |
15a5f6bd | 143 | write_unlock(&detail->hash_lock); |
ebd0cb1a | 144 | cache_fresh_unlocked(old, detail, is_new); |
15a5f6bd N |
145 | return old; |
146 | } | |
147 | write_unlock(&detail->hash_lock); | |
148 | } | |
149 | /* We need to insert a new entry */ | |
150 | tmp = detail->alloc(); | |
151 | if (!tmp) { | |
baab935f | 152 | cache_put(old, detail); |
15a5f6bd N |
153 | return NULL; |
154 | } | |
155 | cache_init(tmp); | |
156 | detail->init(tmp, old); | |
157 | head = &detail->hash_table[hash]; | |
158 | ||
159 | write_lock(&detail->hash_lock); | |
160 | if (test_bit(CACHE_NEGATIVE, &new->flags)) | |
161 | set_bit(CACHE_NEGATIVE, &tmp->flags); | |
162 | else | |
163 | detail->update(tmp, new); | |
164 | tmp->next = *head; | |
165 | *head = tmp; | |
f2d39586 | 166 | detail->entries++; |
15a5f6bd | 167 | cache_get(tmp); |
ebd0cb1a N |
168 | is_new = cache_fresh_locked(tmp, new->expiry_time); |
169 | cache_fresh_locked(old, 0); | |
15a5f6bd | 170 | write_unlock(&detail->hash_lock); |
ebd0cb1a N |
171 | cache_fresh_unlocked(tmp, detail, is_new); |
172 | cache_fresh_unlocked(old, detail, 0); | |
baab935f | 173 | cache_put(old, detail); |
15a5f6bd N |
174 | return tmp; |
175 | } | |
176 | EXPORT_SYMBOL(sunrpc_cache_update); | |
1da177e4 LT |
177 | |
178 | static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); | |
179 | /* | |
180 | * This is the generic cache management routine for all | |
181 | * the authentication caches. | |
182 | * It checks the currency of a cache item and will (later) | |
183 | * initiate an upcall to fill it if needed. | |
184 | * | |
185 | * | |
186 | * Returns 0 if the cache_head can be used, or cache_puts it and returns | |
187 | * -EAGAIN if upcall is pending, | |
e0bb89ef | 188 | * -ETIMEDOUT if upcall failed and should be retried, |
1da177e4 LT |
189 | * -ENOENT if cache entry was negative |
190 | */ | |
191 | int cache_check(struct cache_detail *detail, | |
192 | struct cache_head *h, struct cache_req *rqstp) | |
193 | { | |
194 | int rv; | |
195 | long refresh_age, age; | |
196 | ||
197 | /* First decide return status as best we can */ | |
198 | if (!test_bit(CACHE_VALID, &h->flags) || | |
199 | h->expiry_time < get_seconds()) | |
200 | rv = -EAGAIN; | |
201 | else if (detail->flush_time > h->last_refresh) | |
202 | rv = -EAGAIN; | |
203 | else { | |
204 | /* entry is valid */ | |
205 | if (test_bit(CACHE_NEGATIVE, &h->flags)) | |
206 | rv = -ENOENT; | |
207 | else rv = 0; | |
208 | } | |
209 | ||
210 | /* now see if we want to start an upcall */ | |
211 | refresh_age = (h->expiry_time - h->last_refresh); | |
212 | age = get_seconds() - h->last_refresh; | |
213 | ||
214 | if (rqstp == NULL) { | |
215 | if (rv == -EAGAIN) | |
216 | rv = -ENOENT; | |
217 | } else if (rv == -EAGAIN || age > refresh_age/2) { | |
46121cf7 CL |
218 | dprintk("RPC: Want update, refage=%ld, age=%ld\n", |
219 | refresh_age, age); | |
1da177e4 LT |
220 | if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { |
221 | switch (cache_make_upcall(detail, h)) { | |
222 | case -EINVAL: | |
223 | clear_bit(CACHE_PENDING, &h->flags); | |
224 | if (rv == -EAGAIN) { | |
225 | set_bit(CACHE_NEGATIVE, &h->flags); | |
ebd0cb1a N |
226 | cache_fresh_unlocked(h, detail, |
227 | cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); | |
1da177e4 LT |
228 | rv = -ENOENT; |
229 | } | |
230 | break; | |
231 | ||
232 | case -EAGAIN: | |
233 | clear_bit(CACHE_PENDING, &h->flags); | |
234 | cache_revisit_request(h); | |
235 | break; | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
240 | if (rv == -EAGAIN) | |
e0bb89ef BF |
241 | if (cache_defer_req(rqstp, h) != 0) |
242 | rv = -ETIMEDOUT; | |
1da177e4 | 243 | |
4013edea | 244 | if (rv) |
baab935f | 245 | cache_put(h, detail); |
1da177e4 LT |
246 | return rv; |
247 | } | |
248 | ||
1da177e4 LT |
249 | /* |
250 | * caches need to be periodically cleaned. | |
251 | * For this we maintain a list of cache_detail and | |
252 | * a current pointer into that list and into the table | |
253 | * for that entry. | |
254 | * | |
255 | * Each time clean_cache is called it finds the next non-empty entry | |
256 | * in the current table and walks the list in that entry | |
257 | * looking for entries that can be removed. | |
258 | * | |
259 | * An entry gets removed if: | |
260 | * - The expiry is before current time | |
261 | * - The last_refresh time is before the flush_time for that cache | |
262 | * | |
263 | * later we might drop old entries with non-NEVER expiry if that table | |
264 | * is getting 'full' for some definition of 'full' | |
265 | * | |
266 | * The question of "how often to scan a table" is an interesting one | |
267 | * and is answered in part by the use of the "nextcheck" field in the | |
268 | * cache_detail. | |
269 | * When a scan of a table begins, the nextcheck field is set to a time | |
270 | * that is well into the future. | |
271 | * While scanning, if an expiry time is found that is earlier than the | |
272 | * current nextcheck time, nextcheck is set to that expiry time. | |
273 | * If the flush_time is ever set to a time earlier than the nextcheck | |
274 | * time, the nextcheck time is then set to that flush_time. | |
275 | * | |
276 | * A table is then only scanned if the current time is at least | |
277 | * the nextcheck time. | |
cca5172a | 278 | * |
1da177e4 LT |
279 | */ |
280 | ||
281 | static LIST_HEAD(cache_list); | |
282 | static DEFINE_SPINLOCK(cache_list_lock); | |
283 | static struct cache_detail *current_detail; | |
284 | static int current_index; | |
285 | ||
da7071d7 AV |
286 | static const struct file_operations cache_file_operations; |
287 | static const struct file_operations content_file_operations; | |
288 | static const struct file_operations cache_flush_operations; | |
1da177e4 | 289 | |
65f27f38 DH |
290 | static void do_cache_clean(struct work_struct *work); |
291 | static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean); | |
1da177e4 | 292 | |
ffe9386b | 293 | static void remove_cache_proc_entries(struct cache_detail *cd) |
1da177e4 | 294 | { |
ffe9386b BF |
295 | if (cd->proc_ent == NULL) |
296 | return; | |
297 | if (cd->flush_ent) | |
298 | remove_proc_entry("flush", cd->proc_ent); | |
299 | if (cd->channel_ent) | |
300 | remove_proc_entry("channel", cd->proc_ent); | |
301 | if (cd->content_ent) | |
302 | remove_proc_entry("content", cd->proc_ent); | |
303 | cd->proc_ent = NULL; | |
304 | remove_proc_entry(cd->name, proc_net_rpc); | |
305 | } | |
cca5172a | 306 | |
dbf847ec BF |
307 | #ifdef CONFIG_PROC_FS |
308 | static int create_cache_proc_entries(struct cache_detail *cd) | |
ffe9386b BF |
309 | { |
310 | struct proc_dir_entry *p; | |
cca5172a | 311 | |
ffe9386b BF |
312 | cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc); |
313 | if (cd->proc_ent == NULL) | |
dbf847ec | 314 | goto out_nomem; |
ffe9386b BF |
315 | cd->proc_ent->owner = cd->owner; |
316 | cd->channel_ent = cd->content_ent = NULL; | |
317 | ||
318 | p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR, cd->proc_ent); | |
319 | cd->flush_ent = p; | |
320 | if (p == NULL) | |
dbf847ec | 321 | goto out_nomem; |
ffe9386b BF |
322 | p->proc_fops = &cache_flush_operations; |
323 | p->owner = cd->owner; | |
324 | p->data = cd; | |
325 | ||
326 | if (cd->cache_request || cd->cache_parse) { | |
327 | p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR, | |
328 | cd->proc_ent); | |
329 | cd->channel_ent = p; | |
330 | if (p == NULL) | |
dbf847ec | 331 | goto out_nomem; |
ffe9386b BF |
332 | p->proc_fops = &cache_file_operations; |
333 | p->owner = cd->owner; | |
334 | p->data = cd; | |
1da177e4 | 335 | } |
ffe9386b BF |
336 | if (cd->cache_show) { |
337 | p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR, | |
338 | cd->proc_ent); | |
339 | cd->content_ent = p; | |
340 | if (p == NULL) | |
dbf847ec | 341 | goto out_nomem; |
ffe9386b BF |
342 | p->proc_fops = &content_file_operations; |
343 | p->owner = cd->owner; | |
344 | p->data = cd; | |
345 | } | |
dbf847ec BF |
346 | return 0; |
347 | out_nomem: | |
348 | remove_cache_proc_entries(cd); | |
349 | return -ENOMEM; | |
ffe9386b | 350 | } |
dbf847ec BF |
351 | #else /* CONFIG_PROC_FS */ |
352 | static int create_cache_proc_entries(struct cache_detail *cd) | |
353 | { | |
354 | return 0; | |
355 | } | |
356 | #endif | |
ffe9386b | 357 | |
dbf847ec | 358 | int cache_register(struct cache_detail *cd) |
ffe9386b | 359 | { |
dbf847ec BF |
360 | int ret; |
361 | ||
362 | ret = create_cache_proc_entries(cd); | |
363 | if (ret) | |
364 | return ret; | |
1da177e4 LT |
365 | rwlock_init(&cd->hash_lock); |
366 | INIT_LIST_HEAD(&cd->queue); | |
367 | spin_lock(&cache_list_lock); | |
368 | cd->nextcheck = 0; | |
369 | cd->entries = 0; | |
370 | atomic_set(&cd->readers, 0); | |
371 | cd->last_close = 0; | |
372 | cd->last_warn = -1; | |
373 | list_add(&cd->others, &cache_list); | |
374 | spin_unlock(&cache_list_lock); | |
375 | ||
376 | /* start the cleaning process */ | |
52bad64d | 377 | schedule_delayed_work(&cache_cleaner, 0); |
dbf847ec | 378 | return 0; |
1da177e4 LT |
379 | } |
380 | ||
df95a9d4 | 381 | void cache_unregister(struct cache_detail *cd) |
1da177e4 LT |
382 | { |
383 | cache_purge(cd); | |
384 | spin_lock(&cache_list_lock); | |
385 | write_lock(&cd->hash_lock); | |
386 | if (cd->entries || atomic_read(&cd->inuse)) { | |
387 | write_unlock(&cd->hash_lock); | |
388 | spin_unlock(&cache_list_lock); | |
df95a9d4 | 389 | goto out; |
1da177e4 LT |
390 | } |
391 | if (current_detail == cd) | |
392 | current_detail = NULL; | |
393 | list_del_init(&cd->others); | |
394 | write_unlock(&cd->hash_lock); | |
395 | spin_unlock(&cache_list_lock); | |
ffe9386b | 396 | remove_cache_proc_entries(cd); |
1da177e4 LT |
397 | if (list_empty(&cache_list)) { |
398 | /* module must be being unloaded so its safe to kill the worker */ | |
4011cd97 | 399 | cancel_delayed_work_sync(&cache_cleaner); |
1da177e4 | 400 | } |
df95a9d4 BF |
401 | return; |
402 | out: | |
403 | printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name); | |
1da177e4 LT |
404 | } |
405 | ||
406 | /* clean cache tries to find something to clean | |
407 | * and cleans it. | |
408 | * It returns 1 if it cleaned something, | |
409 | * 0 if it didn't find anything this time | |
410 | * -1 if it fell off the end of the list. | |
411 | */ | |
412 | static int cache_clean(void) | |
413 | { | |
414 | int rv = 0; | |
415 | struct list_head *next; | |
416 | ||
417 | spin_lock(&cache_list_lock); | |
418 | ||
419 | /* find a suitable table if we don't already have one */ | |
420 | while (current_detail == NULL || | |
421 | current_index >= current_detail->hash_size) { | |
422 | if (current_detail) | |
423 | next = current_detail->others.next; | |
424 | else | |
425 | next = cache_list.next; | |
426 | if (next == &cache_list) { | |
427 | current_detail = NULL; | |
428 | spin_unlock(&cache_list_lock); | |
429 | return -1; | |
430 | } | |
431 | current_detail = list_entry(next, struct cache_detail, others); | |
432 | if (current_detail->nextcheck > get_seconds()) | |
433 | current_index = current_detail->hash_size; | |
434 | else { | |
435 | current_index = 0; | |
436 | current_detail->nextcheck = get_seconds()+30*60; | |
437 | } | |
438 | } | |
439 | ||
440 | /* find a non-empty bucket in the table */ | |
441 | while (current_detail && | |
442 | current_index < current_detail->hash_size && | |
443 | current_detail->hash_table[current_index] == NULL) | |
444 | current_index++; | |
445 | ||
446 | /* find a cleanable entry in the bucket and clean it, or set to next bucket */ | |
cca5172a | 447 | |
1da177e4 LT |
448 | if (current_detail && current_index < current_detail->hash_size) { |
449 | struct cache_head *ch, **cp; | |
450 | struct cache_detail *d; | |
cca5172a | 451 | |
1da177e4 LT |
452 | write_lock(¤t_detail->hash_lock); |
453 | ||
454 | /* Ok, now to clean this strand */ | |
cca5172a | 455 | |
1da177e4 LT |
456 | cp = & current_detail->hash_table[current_index]; |
457 | ch = *cp; | |
458 | for (; ch; cp= & ch->next, ch= *cp) { | |
459 | if (current_detail->nextcheck > ch->expiry_time) | |
460 | current_detail->nextcheck = ch->expiry_time+1; | |
461 | if (ch->expiry_time >= get_seconds() | |
462 | && ch->last_refresh >= current_detail->flush_time | |
463 | ) | |
464 | continue; | |
465 | if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) | |
466 | queue_loose(current_detail, ch); | |
467 | ||
baab935f | 468 | if (atomic_read(&ch->ref.refcount) == 1) |
1da177e4 LT |
469 | break; |
470 | } | |
471 | if (ch) { | |
472 | *cp = ch->next; | |
473 | ch->next = NULL; | |
474 | current_detail->entries--; | |
475 | rv = 1; | |
476 | } | |
477 | write_unlock(¤t_detail->hash_lock); | |
478 | d = current_detail; | |
479 | if (!ch) | |
480 | current_index ++; | |
481 | spin_unlock(&cache_list_lock); | |
482 | if (ch) | |
baab935f | 483 | cache_put(ch, d); |
1da177e4 LT |
484 | } else |
485 | spin_unlock(&cache_list_lock); | |
486 | ||
487 | return rv; | |
488 | } | |
489 | ||
490 | /* | |
491 | * We want to regularly clean the cache, so we need to schedule some work ... | |
492 | */ | |
65f27f38 | 493 | static void do_cache_clean(struct work_struct *work) |
1da177e4 LT |
494 | { |
495 | int delay = 5; | |
496 | if (cache_clean() == -1) | |
497 | delay = 30*HZ; | |
498 | ||
499 | if (list_empty(&cache_list)) | |
500 | delay = 0; | |
501 | ||
502 | if (delay) | |
503 | schedule_delayed_work(&cache_cleaner, delay); | |
504 | } | |
505 | ||
506 | ||
cca5172a | 507 | /* |
1da177e4 | 508 | * Clean all caches promptly. This just calls cache_clean |
cca5172a | 509 | * repeatedly until we are sure that every cache has had a chance to |
1da177e4 LT |
510 | * be fully cleaned |
511 | */ | |
512 | void cache_flush(void) | |
513 | { | |
514 | while (cache_clean() != -1) | |
515 | cond_resched(); | |
516 | while (cache_clean() != -1) | |
517 | cond_resched(); | |
518 | } | |
519 | ||
520 | void cache_purge(struct cache_detail *detail) | |
521 | { | |
522 | detail->flush_time = LONG_MAX; | |
523 | detail->nextcheck = get_seconds(); | |
524 | cache_flush(); | |
525 | detail->flush_time = 1; | |
526 | } | |
527 | ||
528 | ||
529 | ||
530 | /* | |
531 | * Deferral and Revisiting of Requests. | |
532 | * | |
533 | * If a cache lookup finds a pending entry, we | |
534 | * need to defer the request and revisit it later. | |
535 | * All deferred requests are stored in a hash table, | |
536 | * indexed by "struct cache_head *". | |
537 | * As it may be wasteful to store a whole request | |
cca5172a | 538 | * structure, we allow the request to provide a |
1da177e4 LT |
539 | * deferred form, which must contain a |
540 | * 'struct cache_deferred_req' | |
541 | * This cache_deferred_req contains a method to allow | |
542 | * it to be revisited when cache info is available | |
543 | */ | |
544 | ||
545 | #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) | |
546 | #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) | |
547 | ||
548 | #define DFR_MAX 300 /* ??? */ | |
549 | ||
550 | static DEFINE_SPINLOCK(cache_defer_lock); | |
551 | static LIST_HEAD(cache_defer_list); | |
552 | static struct list_head cache_defer_hash[DFR_HASHSIZE]; | |
553 | static int cache_defer_cnt; | |
554 | ||
e0bb89ef | 555 | static int cache_defer_req(struct cache_req *req, struct cache_head *item) |
1da177e4 LT |
556 | { |
557 | struct cache_deferred_req *dreq; | |
558 | int hash = DFR_HASH(item); | |
559 | ||
01f3bd1f BF |
560 | if (cache_defer_cnt >= DFR_MAX) { |
561 | /* too much in the cache, randomly drop this one, | |
562 | * or continue and drop the oldest below | |
563 | */ | |
564 | if (net_random()&1) | |
565 | return -ETIMEDOUT; | |
566 | } | |
1da177e4 LT |
567 | dreq = req->defer(req); |
568 | if (dreq == NULL) | |
e0bb89ef | 569 | return -ETIMEDOUT; |
1da177e4 LT |
570 | |
571 | dreq->item = item; | |
572 | dreq->recv_time = get_seconds(); | |
573 | ||
574 | spin_lock(&cache_defer_lock); | |
575 | ||
576 | list_add(&dreq->recent, &cache_defer_list); | |
577 | ||
578 | if (cache_defer_hash[hash].next == NULL) | |
579 | INIT_LIST_HEAD(&cache_defer_hash[hash]); | |
580 | list_add(&dreq->hash, &cache_defer_hash[hash]); | |
581 | ||
582 | /* it is in, now maybe clean up */ | |
583 | dreq = NULL; | |
584 | if (++cache_defer_cnt > DFR_MAX) { | |
01f3bd1f BF |
585 | dreq = list_entry(cache_defer_list.prev, |
586 | struct cache_deferred_req, recent); | |
1da177e4 LT |
587 | list_del(&dreq->recent); |
588 | list_del(&dreq->hash); | |
589 | cache_defer_cnt--; | |
590 | } | |
591 | spin_unlock(&cache_defer_lock); | |
592 | ||
593 | if (dreq) { | |
594 | /* there was one too many */ | |
595 | dreq->revisit(dreq, 1); | |
596 | } | |
4013edea | 597 | if (!test_bit(CACHE_PENDING, &item->flags)) { |
1da177e4 LT |
598 | /* must have just been validated... */ |
599 | cache_revisit_request(item); | |
600 | } | |
e0bb89ef | 601 | return 0; |
1da177e4 LT |
602 | } |
603 | ||
604 | static void cache_revisit_request(struct cache_head *item) | |
605 | { | |
606 | struct cache_deferred_req *dreq; | |
607 | struct list_head pending; | |
608 | ||
609 | struct list_head *lp; | |
610 | int hash = DFR_HASH(item); | |
611 | ||
612 | INIT_LIST_HEAD(&pending); | |
613 | spin_lock(&cache_defer_lock); | |
cca5172a | 614 | |
1da177e4 LT |
615 | lp = cache_defer_hash[hash].next; |
616 | if (lp) { | |
617 | while (lp != &cache_defer_hash[hash]) { | |
618 | dreq = list_entry(lp, struct cache_deferred_req, hash); | |
619 | lp = lp->next; | |
620 | if (dreq->item == item) { | |
621 | list_del(&dreq->hash); | |
622 | list_move(&dreq->recent, &pending); | |
623 | cache_defer_cnt--; | |
624 | } | |
625 | } | |
626 | } | |
627 | spin_unlock(&cache_defer_lock); | |
628 | ||
629 | while (!list_empty(&pending)) { | |
630 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); | |
631 | list_del_init(&dreq->recent); | |
632 | dreq->revisit(dreq, 0); | |
633 | } | |
634 | } | |
635 | ||
636 | void cache_clean_deferred(void *owner) | |
637 | { | |
638 | struct cache_deferred_req *dreq, *tmp; | |
639 | struct list_head pending; | |
640 | ||
641 | ||
642 | INIT_LIST_HEAD(&pending); | |
643 | spin_lock(&cache_defer_lock); | |
cca5172a | 644 | |
1da177e4 LT |
645 | list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { |
646 | if (dreq->owner == owner) { | |
647 | list_del(&dreq->hash); | |
648 | list_move(&dreq->recent, &pending); | |
649 | cache_defer_cnt--; | |
650 | } | |
651 | } | |
652 | spin_unlock(&cache_defer_lock); | |
653 | ||
654 | while (!list_empty(&pending)) { | |
655 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); | |
656 | list_del_init(&dreq->recent); | |
657 | dreq->revisit(dreq, 1); | |
658 | } | |
659 | } | |
660 | ||
661 | /* | |
662 | * communicate with user-space | |
663 | * | |
a490c681 BF |
664 | * We have a magic /proc file - /proc/sunrpc/<cachename>/channel. |
665 | * On read, you get a full request, or block. | |
666 | * On write, an update request is processed. | |
667 | * Poll works if anything to read, and always allows write. | |
1da177e4 | 668 | * |
cca5172a | 669 | * Implemented by linked list of requests. Each open file has |
a490c681 | 670 | * a ->private that also exists in this list. New requests are added |
1da177e4 LT |
671 | * to the end and may wakeup and preceding readers. |
672 | * New readers are added to the head. If, on read, an item is found with | |
673 | * CACHE_UPCALLING clear, we free it from the list. | |
674 | * | |
675 | */ | |
676 | ||
677 | static DEFINE_SPINLOCK(queue_lock); | |
4a3e2f71 | 678 | static DEFINE_MUTEX(queue_io_mutex); |
1da177e4 LT |
679 | |
680 | struct cache_queue { | |
681 | struct list_head list; | |
682 | int reader; /* if 0, then request */ | |
683 | }; | |
684 | struct cache_request { | |
685 | struct cache_queue q; | |
686 | struct cache_head *item; | |
687 | char * buf; | |
688 | int len; | |
689 | int readers; | |
690 | }; | |
691 | struct cache_reader { | |
692 | struct cache_queue q; | |
693 | int offset; /* if non-0, we have a refcnt on next request */ | |
694 | }; | |
695 | ||
696 | static ssize_t | |
697 | cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
698 | { | |
699 | struct cache_reader *rp = filp->private_data; | |
700 | struct cache_request *rq; | |
303b46bb | 701 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
702 | int err; |
703 | ||
704 | if (count == 0) | |
705 | return 0; | |
706 | ||
4a3e2f71 | 707 | mutex_lock(&queue_io_mutex); /* protect against multiple concurrent |
1da177e4 LT |
708 | * readers on this file */ |
709 | again: | |
710 | spin_lock(&queue_lock); | |
711 | /* need to find next request */ | |
712 | while (rp->q.list.next != &cd->queue && | |
713 | list_entry(rp->q.list.next, struct cache_queue, list) | |
714 | ->reader) { | |
715 | struct list_head *next = rp->q.list.next; | |
716 | list_move(&rp->q.list, next); | |
717 | } | |
718 | if (rp->q.list.next == &cd->queue) { | |
719 | spin_unlock(&queue_lock); | |
4a3e2f71 | 720 | mutex_unlock(&queue_io_mutex); |
09a62660 | 721 | BUG_ON(rp->offset); |
1da177e4 LT |
722 | return 0; |
723 | } | |
724 | rq = container_of(rp->q.list.next, struct cache_request, q.list); | |
09a62660 | 725 | BUG_ON(rq->q.reader); |
1da177e4 LT |
726 | if (rp->offset == 0) |
727 | rq->readers++; | |
728 | spin_unlock(&queue_lock); | |
729 | ||
730 | if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { | |
731 | err = -EAGAIN; | |
732 | spin_lock(&queue_lock); | |
733 | list_move(&rp->q.list, &rq->q.list); | |
734 | spin_unlock(&queue_lock); | |
735 | } else { | |
736 | if (rp->offset + count > rq->len) | |
737 | count = rq->len - rp->offset; | |
738 | err = -EFAULT; | |
739 | if (copy_to_user(buf, rq->buf + rp->offset, count)) | |
740 | goto out; | |
741 | rp->offset += count; | |
742 | if (rp->offset >= rq->len) { | |
743 | rp->offset = 0; | |
744 | spin_lock(&queue_lock); | |
745 | list_move(&rp->q.list, &rq->q.list); | |
746 | spin_unlock(&queue_lock); | |
747 | } | |
748 | err = 0; | |
749 | } | |
750 | out: | |
751 | if (rp->offset == 0) { | |
752 | /* need to release rq */ | |
753 | spin_lock(&queue_lock); | |
754 | rq->readers--; | |
755 | if (rq->readers == 0 && | |
756 | !test_bit(CACHE_PENDING, &rq->item->flags)) { | |
757 | list_del(&rq->q.list); | |
758 | spin_unlock(&queue_lock); | |
baab935f | 759 | cache_put(rq->item, cd); |
1da177e4 LT |
760 | kfree(rq->buf); |
761 | kfree(rq); | |
762 | } else | |
763 | spin_unlock(&queue_lock); | |
764 | } | |
765 | if (err == -EAGAIN) | |
766 | goto again; | |
4a3e2f71 | 767 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
768 | return err ? err : count; |
769 | } | |
770 | ||
4a3e2f71 | 771 | static char write_buf[8192]; /* protected by queue_io_mutex */ |
1da177e4 LT |
772 | |
773 | static ssize_t | |
774 | cache_write(struct file *filp, const char __user *buf, size_t count, | |
775 | loff_t *ppos) | |
776 | { | |
777 | int err; | |
303b46bb | 778 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
779 | |
780 | if (count == 0) | |
781 | return 0; | |
782 | if (count >= sizeof(write_buf)) | |
783 | return -EINVAL; | |
784 | ||
4a3e2f71 | 785 | mutex_lock(&queue_io_mutex); |
1da177e4 LT |
786 | |
787 | if (copy_from_user(write_buf, buf, count)) { | |
4a3e2f71 | 788 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
789 | return -EFAULT; |
790 | } | |
791 | write_buf[count] = '\0'; | |
792 | if (cd->cache_parse) | |
793 | err = cd->cache_parse(cd, write_buf, count); | |
794 | else | |
795 | err = -EINVAL; | |
796 | ||
4a3e2f71 | 797 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
798 | return err ? err : count; |
799 | } | |
800 | ||
801 | static DECLARE_WAIT_QUEUE_HEAD(queue_wait); | |
802 | ||
803 | static unsigned int | |
804 | cache_poll(struct file *filp, poll_table *wait) | |
805 | { | |
806 | unsigned int mask; | |
807 | struct cache_reader *rp = filp->private_data; | |
808 | struct cache_queue *cq; | |
303b46bb | 809 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
810 | |
811 | poll_wait(filp, &queue_wait, wait); | |
812 | ||
813 | /* alway allow write */ | |
814 | mask = POLL_OUT | POLLWRNORM; | |
815 | ||
816 | if (!rp) | |
817 | return mask; | |
818 | ||
819 | spin_lock(&queue_lock); | |
820 | ||
821 | for (cq= &rp->q; &cq->list != &cd->queue; | |
822 | cq = list_entry(cq->list.next, struct cache_queue, list)) | |
823 | if (!cq->reader) { | |
824 | mask |= POLLIN | POLLRDNORM; | |
825 | break; | |
826 | } | |
827 | spin_unlock(&queue_lock); | |
828 | return mask; | |
829 | } | |
830 | ||
831 | static int | |
832 | cache_ioctl(struct inode *ino, struct file *filp, | |
833 | unsigned int cmd, unsigned long arg) | |
834 | { | |
835 | int len = 0; | |
836 | struct cache_reader *rp = filp->private_data; | |
837 | struct cache_queue *cq; | |
838 | struct cache_detail *cd = PDE(ino)->data; | |
839 | ||
840 | if (cmd != FIONREAD || !rp) | |
841 | return -EINVAL; | |
842 | ||
843 | spin_lock(&queue_lock); | |
844 | ||
845 | /* only find the length remaining in current request, | |
846 | * or the length of the next request | |
847 | */ | |
848 | for (cq= &rp->q; &cq->list != &cd->queue; | |
849 | cq = list_entry(cq->list.next, struct cache_queue, list)) | |
850 | if (!cq->reader) { | |
851 | struct cache_request *cr = | |
852 | container_of(cq, struct cache_request, q); | |
853 | len = cr->len - rp->offset; | |
854 | break; | |
855 | } | |
856 | spin_unlock(&queue_lock); | |
857 | ||
858 | return put_user(len, (int __user *)arg); | |
859 | } | |
860 | ||
861 | static int | |
862 | cache_open(struct inode *inode, struct file *filp) | |
863 | { | |
864 | struct cache_reader *rp = NULL; | |
865 | ||
866 | nonseekable_open(inode, filp); | |
867 | if (filp->f_mode & FMODE_READ) { | |
868 | struct cache_detail *cd = PDE(inode)->data; | |
869 | ||
870 | rp = kmalloc(sizeof(*rp), GFP_KERNEL); | |
871 | if (!rp) | |
872 | return -ENOMEM; | |
873 | rp->offset = 0; | |
874 | rp->q.reader = 1; | |
875 | atomic_inc(&cd->readers); | |
876 | spin_lock(&queue_lock); | |
877 | list_add(&rp->q.list, &cd->queue); | |
878 | spin_unlock(&queue_lock); | |
879 | } | |
880 | filp->private_data = rp; | |
881 | return 0; | |
882 | } | |
883 | ||
884 | static int | |
885 | cache_release(struct inode *inode, struct file *filp) | |
886 | { | |
887 | struct cache_reader *rp = filp->private_data; | |
888 | struct cache_detail *cd = PDE(inode)->data; | |
889 | ||
890 | if (rp) { | |
891 | spin_lock(&queue_lock); | |
892 | if (rp->offset) { | |
893 | struct cache_queue *cq; | |
894 | for (cq= &rp->q; &cq->list != &cd->queue; | |
895 | cq = list_entry(cq->list.next, struct cache_queue, list)) | |
896 | if (!cq->reader) { | |
897 | container_of(cq, struct cache_request, q) | |
898 | ->readers--; | |
899 | break; | |
900 | } | |
901 | rp->offset = 0; | |
902 | } | |
903 | list_del(&rp->q.list); | |
904 | spin_unlock(&queue_lock); | |
905 | ||
906 | filp->private_data = NULL; | |
907 | kfree(rp); | |
908 | ||
909 | cd->last_close = get_seconds(); | |
910 | atomic_dec(&cd->readers); | |
911 | } | |
912 | return 0; | |
913 | } | |
914 | ||
915 | ||
916 | ||
da7071d7 | 917 | static const struct file_operations cache_file_operations = { |
1da177e4 LT |
918 | .owner = THIS_MODULE, |
919 | .llseek = no_llseek, | |
920 | .read = cache_read, | |
921 | .write = cache_write, | |
922 | .poll = cache_poll, | |
923 | .ioctl = cache_ioctl, /* for FIONREAD */ | |
924 | .open = cache_open, | |
925 | .release = cache_release, | |
926 | }; | |
927 | ||
928 | ||
929 | static void queue_loose(struct cache_detail *detail, struct cache_head *ch) | |
930 | { | |
931 | struct cache_queue *cq; | |
932 | spin_lock(&queue_lock); | |
933 | list_for_each_entry(cq, &detail->queue, list) | |
934 | if (!cq->reader) { | |
935 | struct cache_request *cr = container_of(cq, struct cache_request, q); | |
936 | if (cr->item != ch) | |
937 | continue; | |
938 | if (cr->readers != 0) | |
4013edea | 939 | continue; |
1da177e4 LT |
940 | list_del(&cr->q.list); |
941 | spin_unlock(&queue_lock); | |
baab935f | 942 | cache_put(cr->item, detail); |
1da177e4 LT |
943 | kfree(cr->buf); |
944 | kfree(cr); | |
945 | return; | |
946 | } | |
947 | spin_unlock(&queue_lock); | |
948 | } | |
949 | ||
950 | /* | |
951 | * Support routines for text-based upcalls. | |
952 | * Fields are separated by spaces. | |
953 | * Fields are either mangled to quote space tab newline slosh with slosh | |
954 | * or a hexified with a leading \x | |
955 | * Record is terminated with newline. | |
956 | * | |
957 | */ | |
958 | ||
959 | void qword_add(char **bpp, int *lp, char *str) | |
960 | { | |
961 | char *bp = *bpp; | |
962 | int len = *lp; | |
963 | char c; | |
964 | ||
965 | if (len < 0) return; | |
966 | ||
967 | while ((c=*str++) && len) | |
968 | switch(c) { | |
969 | case ' ': | |
970 | case '\t': | |
971 | case '\n': | |
972 | case '\\': | |
973 | if (len >= 4) { | |
974 | *bp++ = '\\'; | |
975 | *bp++ = '0' + ((c & 0300)>>6); | |
976 | *bp++ = '0' + ((c & 0070)>>3); | |
977 | *bp++ = '0' + ((c & 0007)>>0); | |
978 | } | |
979 | len -= 4; | |
980 | break; | |
981 | default: | |
982 | *bp++ = c; | |
983 | len--; | |
984 | } | |
985 | if (c || len <1) len = -1; | |
986 | else { | |
987 | *bp++ = ' '; | |
988 | len--; | |
989 | } | |
990 | *bpp = bp; | |
991 | *lp = len; | |
992 | } | |
993 | ||
994 | void qword_addhex(char **bpp, int *lp, char *buf, int blen) | |
995 | { | |
996 | char *bp = *bpp; | |
997 | int len = *lp; | |
998 | ||
999 | if (len < 0) return; | |
1000 | ||
1001 | if (len > 2) { | |
1002 | *bp++ = '\\'; | |
1003 | *bp++ = 'x'; | |
1004 | len -= 2; | |
1005 | while (blen && len >= 2) { | |
1006 | unsigned char c = *buf++; | |
1007 | *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); | |
1008 | *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); | |
1009 | len -= 2; | |
1010 | blen--; | |
1011 | } | |
1012 | } | |
1013 | if (blen || len<1) len = -1; | |
1014 | else { | |
1015 | *bp++ = ' '; | |
1016 | len--; | |
1017 | } | |
1018 | *bpp = bp; | |
1019 | *lp = len; | |
1020 | } | |
1021 | ||
1022 | static void warn_no_listener(struct cache_detail *detail) | |
1023 | { | |
1024 | if (detail->last_warn != detail->last_close) { | |
1025 | detail->last_warn = detail->last_close; | |
1026 | if (detail->warn_no_listener) | |
1027 | detail->warn_no_listener(detail); | |
1028 | } | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * register an upcall request to user-space. | |
1033 | * Each request is at most one page long. | |
1034 | */ | |
1035 | static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) | |
1036 | { | |
1037 | ||
1038 | char *buf; | |
1039 | struct cache_request *crq; | |
1040 | char *bp; | |
1041 | int len; | |
1042 | ||
1043 | if (detail->cache_request == NULL) | |
1044 | return -EINVAL; | |
1045 | ||
1046 | if (atomic_read(&detail->readers) == 0 && | |
1047 | detail->last_close < get_seconds() - 30) { | |
1048 | warn_no_listener(detail); | |
1049 | return -EINVAL; | |
1050 | } | |
1051 | ||
1052 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
1053 | if (!buf) | |
1054 | return -EAGAIN; | |
1055 | ||
1056 | crq = kmalloc(sizeof (*crq), GFP_KERNEL); | |
1057 | if (!crq) { | |
1058 | kfree(buf); | |
1059 | return -EAGAIN; | |
1060 | } | |
1061 | ||
1062 | bp = buf; len = PAGE_SIZE; | |
1063 | ||
1064 | detail->cache_request(detail, h, &bp, &len); | |
1065 | ||
1066 | if (len < 0) { | |
1067 | kfree(buf); | |
1068 | kfree(crq); | |
1069 | return -EAGAIN; | |
1070 | } | |
1071 | crq->q.reader = 0; | |
1072 | crq->item = cache_get(h); | |
1073 | crq->buf = buf; | |
1074 | crq->len = PAGE_SIZE - len; | |
1075 | crq->readers = 0; | |
1076 | spin_lock(&queue_lock); | |
1077 | list_add_tail(&crq->q.list, &detail->queue); | |
1078 | spin_unlock(&queue_lock); | |
1079 | wake_up(&queue_wait); | |
1080 | return 0; | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * parse a message from user-space and pass it | |
1085 | * to an appropriate cache | |
1086 | * Messages are, like requests, separated into fields by | |
1087 | * spaces and dequotes as \xHEXSTRING or embedded \nnn octal | |
1088 | * | |
cca5172a | 1089 | * Message is |
1da177e4 LT |
1090 | * reply cachename expiry key ... content.... |
1091 | * | |
cca5172a | 1092 | * key and content are both parsed by cache |
1da177e4 LT |
1093 | */ |
1094 | ||
1095 | #define isodigit(c) (isdigit(c) && c <= '7') | |
1096 | int qword_get(char **bpp, char *dest, int bufsize) | |
1097 | { | |
1098 | /* return bytes copied, or -1 on error */ | |
1099 | char *bp = *bpp; | |
1100 | int len = 0; | |
1101 | ||
1102 | while (*bp == ' ') bp++; | |
1103 | ||
1104 | if (bp[0] == '\\' && bp[1] == 'x') { | |
1105 | /* HEX STRING */ | |
1106 | bp += 2; | |
1107 | while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { | |
1108 | int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; | |
1109 | bp++; | |
1110 | byte <<= 4; | |
1111 | byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; | |
1112 | *dest++ = byte; | |
1113 | bp++; | |
1114 | len++; | |
1115 | } | |
1116 | } else { | |
1117 | /* text with \nnn octal quoting */ | |
1118 | while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { | |
1119 | if (*bp == '\\' && | |
1120 | isodigit(bp[1]) && (bp[1] <= '3') && | |
1121 | isodigit(bp[2]) && | |
1122 | isodigit(bp[3])) { | |
1123 | int byte = (*++bp -'0'); | |
1124 | bp++; | |
1125 | byte = (byte << 3) | (*bp++ - '0'); | |
1126 | byte = (byte << 3) | (*bp++ - '0'); | |
1127 | *dest++ = byte; | |
1128 | len++; | |
1129 | } else { | |
1130 | *dest++ = *bp++; | |
1131 | len++; | |
1132 | } | |
1133 | } | |
1134 | } | |
1135 | ||
1136 | if (*bp != ' ' && *bp != '\n' && *bp != '\0') | |
1137 | return -1; | |
1138 | while (*bp == ' ') bp++; | |
1139 | *bpp = bp; | |
1140 | *dest = '\0'; | |
1141 | return len; | |
1142 | } | |
1143 | ||
1144 | ||
1145 | /* | |
1146 | * support /proc/sunrpc/cache/$CACHENAME/content | |
1147 | * as a seqfile. | |
1148 | * We call ->cache_show passing NULL for the item to | |
1149 | * get a header, then pass each real item in the cache | |
1150 | */ | |
1151 | ||
1152 | struct handle { | |
1153 | struct cache_detail *cd; | |
1154 | }; | |
1155 | ||
1156 | static void *c_start(struct seq_file *m, loff_t *pos) | |
9a429c49 | 1157 | __acquires(cd->hash_lock) |
1da177e4 LT |
1158 | { |
1159 | loff_t n = *pos; | |
1160 | unsigned hash, entry; | |
1161 | struct cache_head *ch; | |
1162 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
cca5172a | 1163 | |
1da177e4 LT |
1164 | |
1165 | read_lock(&cd->hash_lock); | |
1166 | if (!n--) | |
1167 | return SEQ_START_TOKEN; | |
1168 | hash = n >> 32; | |
1169 | entry = n & ((1LL<<32) - 1); | |
1170 | ||
1171 | for (ch=cd->hash_table[hash]; ch; ch=ch->next) | |
1172 | if (!entry--) | |
1173 | return ch; | |
1174 | n &= ~((1LL<<32) - 1); | |
1175 | do { | |
1176 | hash++; | |
1177 | n += 1LL<<32; | |
cca5172a | 1178 | } while(hash < cd->hash_size && |
1da177e4 LT |
1179 | cd->hash_table[hash]==NULL); |
1180 | if (hash >= cd->hash_size) | |
1181 | return NULL; | |
1182 | *pos = n+1; | |
1183 | return cd->hash_table[hash]; | |
1184 | } | |
1185 | ||
1186 | static void *c_next(struct seq_file *m, void *p, loff_t *pos) | |
1187 | { | |
1188 | struct cache_head *ch = p; | |
1189 | int hash = (*pos >> 32); | |
1190 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1191 | ||
1192 | if (p == SEQ_START_TOKEN) | |
1193 | hash = 0; | |
1194 | else if (ch->next == NULL) { | |
1195 | hash++; | |
1196 | *pos += 1LL<<32; | |
1197 | } else { | |
1198 | ++*pos; | |
1199 | return ch->next; | |
1200 | } | |
1201 | *pos &= ~((1LL<<32) - 1); | |
1202 | while (hash < cd->hash_size && | |
1203 | cd->hash_table[hash] == NULL) { | |
1204 | hash++; | |
1205 | *pos += 1LL<<32; | |
1206 | } | |
1207 | if (hash >= cd->hash_size) | |
1208 | return NULL; | |
1209 | ++*pos; | |
1210 | return cd->hash_table[hash]; | |
1211 | } | |
1212 | ||
1213 | static void c_stop(struct seq_file *m, void *p) | |
9a429c49 | 1214 | __releases(cd->hash_lock) |
1da177e4 LT |
1215 | { |
1216 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1217 | read_unlock(&cd->hash_lock); | |
1218 | } | |
1219 | ||
1220 | static int c_show(struct seq_file *m, void *p) | |
1221 | { | |
1222 | struct cache_head *cp = p; | |
1223 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1224 | ||
1225 | if (p == SEQ_START_TOKEN) | |
1226 | return cd->cache_show(m, cd, NULL); | |
1227 | ||
1228 | ifdebug(CACHE) | |
4013edea | 1229 | seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", |
baab935f | 1230 | cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); |
1da177e4 LT |
1231 | cache_get(cp); |
1232 | if (cache_check(cd, cp, NULL)) | |
1233 | /* cache_check does a cache_put on failure */ | |
1234 | seq_printf(m, "# "); | |
1235 | else | |
1236 | cache_put(cp, cd); | |
1237 | ||
1238 | return cd->cache_show(m, cd, cp); | |
1239 | } | |
1240 | ||
56b3d975 | 1241 | static const struct seq_operations cache_content_op = { |
1da177e4 LT |
1242 | .start = c_start, |
1243 | .next = c_next, | |
1244 | .stop = c_stop, | |
1245 | .show = c_show, | |
1246 | }; | |
1247 | ||
1248 | static int content_open(struct inode *inode, struct file *file) | |
1249 | { | |
1da177e4 LT |
1250 | struct handle *han; |
1251 | struct cache_detail *cd = PDE(inode)->data; | |
1252 | ||
ec931035 | 1253 | han = __seq_open_private(file, &cache_content_op, sizeof(*han)); |
1da177e4 LT |
1254 | if (han == NULL) |
1255 | return -ENOMEM; | |
1256 | ||
1257 | han->cd = cd; | |
ec931035 | 1258 | return 0; |
1da177e4 | 1259 | } |
1da177e4 | 1260 | |
da7071d7 | 1261 | static const struct file_operations content_file_operations = { |
1da177e4 LT |
1262 | .open = content_open, |
1263 | .read = seq_read, | |
1264 | .llseek = seq_lseek, | |
14690fc6 | 1265 | .release = seq_release_private, |
1da177e4 LT |
1266 | }; |
1267 | ||
1268 | static ssize_t read_flush(struct file *file, char __user *buf, | |
1269 | size_t count, loff_t *ppos) | |
1270 | { | |
303b46bb | 1271 | struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; |
1da177e4 LT |
1272 | char tbuf[20]; |
1273 | unsigned long p = *ppos; | |
01b2969a | 1274 | size_t len; |
1da177e4 LT |
1275 | |
1276 | sprintf(tbuf, "%lu\n", cd->flush_time); | |
1277 | len = strlen(tbuf); | |
1278 | if (p >= len) | |
1279 | return 0; | |
1280 | len -= p; | |
01b2969a CL |
1281 | if (len > count) |
1282 | len = count; | |
1da177e4 | 1283 | if (copy_to_user(buf, (void*)(tbuf+p), len)) |
01b2969a CL |
1284 | return -EFAULT; |
1285 | *ppos += len; | |
1da177e4 LT |
1286 | return len; |
1287 | } | |
1288 | ||
1289 | static ssize_t write_flush(struct file * file, const char __user * buf, | |
1290 | size_t count, loff_t *ppos) | |
1291 | { | |
303b46bb | 1292 | struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; |
1da177e4 LT |
1293 | char tbuf[20]; |
1294 | char *ep; | |
1295 | long flushtime; | |
1296 | if (*ppos || count > sizeof(tbuf)-1) | |
1297 | return -EINVAL; | |
1298 | if (copy_from_user(tbuf, buf, count)) | |
1299 | return -EFAULT; | |
1300 | tbuf[count] = 0; | |
1301 | flushtime = simple_strtoul(tbuf, &ep, 0); | |
1302 | if (*ep && *ep != '\n') | |
1303 | return -EINVAL; | |
1304 | ||
1305 | cd->flush_time = flushtime; | |
1306 | cd->nextcheck = get_seconds(); | |
1307 | cache_flush(); | |
1308 | ||
1309 | *ppos += count; | |
1310 | return count; | |
1311 | } | |
1312 | ||
da7071d7 | 1313 | static const struct file_operations cache_flush_operations = { |
1da177e4 LT |
1314 | .open = nonseekable_open, |
1315 | .read = read_flush, | |
1316 | .write = write_flush, | |
1317 | }; |