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 | } | |
24c3767e | 101 | EXPORT_SYMBOL_GPL(sunrpc_cache_lookup); |
15a5f6bd | 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 | } | |
24c3767e | 176 | EXPORT_SYMBOL_GPL(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 | } | |
24c3767e | 248 | EXPORT_SYMBOL_GPL(cache_check); |
1da177e4 | 249 | |
1da177e4 LT |
250 | /* |
251 | * caches need to be periodically cleaned. | |
252 | * For this we maintain a list of cache_detail and | |
253 | * a current pointer into that list and into the table | |
254 | * for that entry. | |
255 | * | |
256 | * Each time clean_cache is called it finds the next non-empty entry | |
257 | * in the current table and walks the list in that entry | |
258 | * looking for entries that can be removed. | |
259 | * | |
260 | * An entry gets removed if: | |
261 | * - The expiry is before current time | |
262 | * - The last_refresh time is before the flush_time for that cache | |
263 | * | |
264 | * later we might drop old entries with non-NEVER expiry if that table | |
265 | * is getting 'full' for some definition of 'full' | |
266 | * | |
267 | * The question of "how often to scan a table" is an interesting one | |
268 | * and is answered in part by the use of the "nextcheck" field in the | |
269 | * cache_detail. | |
270 | * When a scan of a table begins, the nextcheck field is set to a time | |
271 | * that is well into the future. | |
272 | * While scanning, if an expiry time is found that is earlier than the | |
273 | * current nextcheck time, nextcheck is set to that expiry time. | |
274 | * If the flush_time is ever set to a time earlier than the nextcheck | |
275 | * time, the nextcheck time is then set to that flush_time. | |
276 | * | |
277 | * A table is then only scanned if the current time is at least | |
278 | * the nextcheck time. | |
cca5172a | 279 | * |
1da177e4 LT |
280 | */ |
281 | ||
282 | static LIST_HEAD(cache_list); | |
283 | static DEFINE_SPINLOCK(cache_list_lock); | |
284 | static struct cache_detail *current_detail; | |
285 | static int current_index; | |
286 | ||
da7071d7 AV |
287 | static const struct file_operations cache_file_operations; |
288 | static const struct file_operations content_file_operations; | |
289 | static const struct file_operations cache_flush_operations; | |
1da177e4 | 290 | |
65f27f38 DH |
291 | static void do_cache_clean(struct work_struct *work); |
292 | static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean); | |
1da177e4 | 293 | |
ffe9386b | 294 | static void remove_cache_proc_entries(struct cache_detail *cd) |
1da177e4 | 295 | { |
ffe9386b BF |
296 | if (cd->proc_ent == NULL) |
297 | return; | |
298 | if (cd->flush_ent) | |
299 | remove_proc_entry("flush", cd->proc_ent); | |
300 | if (cd->channel_ent) | |
301 | remove_proc_entry("channel", cd->proc_ent); | |
302 | if (cd->content_ent) | |
303 | remove_proc_entry("content", cd->proc_ent); | |
304 | cd->proc_ent = NULL; | |
305 | remove_proc_entry(cd->name, proc_net_rpc); | |
306 | } | |
cca5172a | 307 | |
dbf847ec BF |
308 | #ifdef CONFIG_PROC_FS |
309 | static int create_cache_proc_entries(struct cache_detail *cd) | |
ffe9386b BF |
310 | { |
311 | struct proc_dir_entry *p; | |
cca5172a | 312 | |
ffe9386b BF |
313 | cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc); |
314 | if (cd->proc_ent == NULL) | |
dbf847ec | 315 | goto out_nomem; |
ffe9386b BF |
316 | cd->channel_ent = cd->content_ent = NULL; |
317 | ||
e7fe2336 DL |
318 | p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR, |
319 | cd->proc_ent, &cache_flush_operations, cd); | |
ffe9386b BF |
320 | cd->flush_ent = p; |
321 | if (p == NULL) | |
dbf847ec | 322 | goto out_nomem; |
ffe9386b BF |
323 | |
324 | if (cd->cache_request || cd->cache_parse) { | |
e7fe2336 DL |
325 | p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR, |
326 | cd->proc_ent, &cache_file_operations, cd); | |
ffe9386b BF |
327 | cd->channel_ent = p; |
328 | if (p == NULL) | |
dbf847ec | 329 | goto out_nomem; |
1da177e4 | 330 | } |
ffe9386b | 331 | if (cd->cache_show) { |
e7fe2336 DL |
332 | p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR, |
333 | cd->proc_ent, &content_file_operations, cd); | |
ffe9386b BF |
334 | cd->content_ent = p; |
335 | if (p == NULL) | |
dbf847ec | 336 | goto out_nomem; |
ffe9386b | 337 | } |
dbf847ec BF |
338 | return 0; |
339 | out_nomem: | |
340 | remove_cache_proc_entries(cd); | |
341 | return -ENOMEM; | |
ffe9386b | 342 | } |
dbf847ec BF |
343 | #else /* CONFIG_PROC_FS */ |
344 | static int create_cache_proc_entries(struct cache_detail *cd) | |
345 | { | |
346 | return 0; | |
347 | } | |
348 | #endif | |
ffe9386b | 349 | |
dbf847ec | 350 | int cache_register(struct cache_detail *cd) |
ffe9386b | 351 | { |
dbf847ec BF |
352 | int ret; |
353 | ||
354 | ret = create_cache_proc_entries(cd); | |
355 | if (ret) | |
356 | return ret; | |
1da177e4 LT |
357 | rwlock_init(&cd->hash_lock); |
358 | INIT_LIST_HEAD(&cd->queue); | |
359 | spin_lock(&cache_list_lock); | |
360 | cd->nextcheck = 0; | |
361 | cd->entries = 0; | |
362 | atomic_set(&cd->readers, 0); | |
363 | cd->last_close = 0; | |
364 | cd->last_warn = -1; | |
365 | list_add(&cd->others, &cache_list); | |
366 | spin_unlock(&cache_list_lock); | |
367 | ||
368 | /* start the cleaning process */ | |
52bad64d | 369 | schedule_delayed_work(&cache_cleaner, 0); |
dbf847ec | 370 | return 0; |
1da177e4 | 371 | } |
24c3767e | 372 | EXPORT_SYMBOL_GPL(cache_register); |
1da177e4 | 373 | |
df95a9d4 | 374 | void cache_unregister(struct cache_detail *cd) |
1da177e4 LT |
375 | { |
376 | cache_purge(cd); | |
377 | spin_lock(&cache_list_lock); | |
378 | write_lock(&cd->hash_lock); | |
379 | if (cd->entries || atomic_read(&cd->inuse)) { | |
380 | write_unlock(&cd->hash_lock); | |
381 | spin_unlock(&cache_list_lock); | |
df95a9d4 | 382 | goto out; |
1da177e4 LT |
383 | } |
384 | if (current_detail == cd) | |
385 | current_detail = NULL; | |
386 | list_del_init(&cd->others); | |
387 | write_unlock(&cd->hash_lock); | |
388 | spin_unlock(&cache_list_lock); | |
ffe9386b | 389 | remove_cache_proc_entries(cd); |
1da177e4 LT |
390 | if (list_empty(&cache_list)) { |
391 | /* module must be being unloaded so its safe to kill the worker */ | |
4011cd97 | 392 | cancel_delayed_work_sync(&cache_cleaner); |
1da177e4 | 393 | } |
df95a9d4 BF |
394 | return; |
395 | out: | |
396 | printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name); | |
1da177e4 | 397 | } |
24c3767e | 398 | EXPORT_SYMBOL_GPL(cache_unregister); |
1da177e4 LT |
399 | |
400 | /* clean cache tries to find something to clean | |
401 | * and cleans it. | |
402 | * It returns 1 if it cleaned something, | |
403 | * 0 if it didn't find anything this time | |
404 | * -1 if it fell off the end of the list. | |
405 | */ | |
406 | static int cache_clean(void) | |
407 | { | |
408 | int rv = 0; | |
409 | struct list_head *next; | |
410 | ||
411 | spin_lock(&cache_list_lock); | |
412 | ||
413 | /* find a suitable table if we don't already have one */ | |
414 | while (current_detail == NULL || | |
415 | current_index >= current_detail->hash_size) { | |
416 | if (current_detail) | |
417 | next = current_detail->others.next; | |
418 | else | |
419 | next = cache_list.next; | |
420 | if (next == &cache_list) { | |
421 | current_detail = NULL; | |
422 | spin_unlock(&cache_list_lock); | |
423 | return -1; | |
424 | } | |
425 | current_detail = list_entry(next, struct cache_detail, others); | |
426 | if (current_detail->nextcheck > get_seconds()) | |
427 | current_index = current_detail->hash_size; | |
428 | else { | |
429 | current_index = 0; | |
430 | current_detail->nextcheck = get_seconds()+30*60; | |
431 | } | |
432 | } | |
433 | ||
434 | /* find a non-empty bucket in the table */ | |
435 | while (current_detail && | |
436 | current_index < current_detail->hash_size && | |
437 | current_detail->hash_table[current_index] == NULL) | |
438 | current_index++; | |
439 | ||
440 | /* find a cleanable entry in the bucket and clean it, or set to next bucket */ | |
cca5172a | 441 | |
1da177e4 LT |
442 | if (current_detail && current_index < current_detail->hash_size) { |
443 | struct cache_head *ch, **cp; | |
444 | struct cache_detail *d; | |
cca5172a | 445 | |
1da177e4 LT |
446 | write_lock(¤t_detail->hash_lock); |
447 | ||
448 | /* Ok, now to clean this strand */ | |
cca5172a | 449 | |
1da177e4 LT |
450 | cp = & current_detail->hash_table[current_index]; |
451 | ch = *cp; | |
452 | for (; ch; cp= & ch->next, ch= *cp) { | |
453 | if (current_detail->nextcheck > ch->expiry_time) | |
454 | current_detail->nextcheck = ch->expiry_time+1; | |
455 | if (ch->expiry_time >= get_seconds() | |
456 | && ch->last_refresh >= current_detail->flush_time | |
457 | ) | |
458 | continue; | |
459 | if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) | |
460 | queue_loose(current_detail, ch); | |
461 | ||
baab935f | 462 | if (atomic_read(&ch->ref.refcount) == 1) |
1da177e4 LT |
463 | break; |
464 | } | |
465 | if (ch) { | |
466 | *cp = ch->next; | |
467 | ch->next = NULL; | |
468 | current_detail->entries--; | |
469 | rv = 1; | |
470 | } | |
471 | write_unlock(¤t_detail->hash_lock); | |
472 | d = current_detail; | |
473 | if (!ch) | |
474 | current_index ++; | |
475 | spin_unlock(&cache_list_lock); | |
476 | if (ch) | |
baab935f | 477 | cache_put(ch, d); |
1da177e4 LT |
478 | } else |
479 | spin_unlock(&cache_list_lock); | |
480 | ||
481 | return rv; | |
482 | } | |
483 | ||
484 | /* | |
485 | * We want to regularly clean the cache, so we need to schedule some work ... | |
486 | */ | |
65f27f38 | 487 | static void do_cache_clean(struct work_struct *work) |
1da177e4 LT |
488 | { |
489 | int delay = 5; | |
490 | if (cache_clean() == -1) | |
491 | delay = 30*HZ; | |
492 | ||
493 | if (list_empty(&cache_list)) | |
494 | delay = 0; | |
495 | ||
496 | if (delay) | |
497 | schedule_delayed_work(&cache_cleaner, delay); | |
498 | } | |
499 | ||
500 | ||
cca5172a | 501 | /* |
1da177e4 | 502 | * Clean all caches promptly. This just calls cache_clean |
cca5172a | 503 | * repeatedly until we are sure that every cache has had a chance to |
1da177e4 LT |
504 | * be fully cleaned |
505 | */ | |
506 | void cache_flush(void) | |
507 | { | |
508 | while (cache_clean() != -1) | |
509 | cond_resched(); | |
510 | while (cache_clean() != -1) | |
511 | cond_resched(); | |
512 | } | |
24c3767e | 513 | EXPORT_SYMBOL_GPL(cache_flush); |
1da177e4 LT |
514 | |
515 | void cache_purge(struct cache_detail *detail) | |
516 | { | |
517 | detail->flush_time = LONG_MAX; | |
518 | detail->nextcheck = get_seconds(); | |
519 | cache_flush(); | |
520 | detail->flush_time = 1; | |
521 | } | |
24c3767e | 522 | EXPORT_SYMBOL_GPL(cache_purge); |
1da177e4 LT |
523 | |
524 | ||
525 | /* | |
526 | * Deferral and Revisiting of Requests. | |
527 | * | |
528 | * If a cache lookup finds a pending entry, we | |
529 | * need to defer the request and revisit it later. | |
530 | * All deferred requests are stored in a hash table, | |
531 | * indexed by "struct cache_head *". | |
532 | * As it may be wasteful to store a whole request | |
cca5172a | 533 | * structure, we allow the request to provide a |
1da177e4 LT |
534 | * deferred form, which must contain a |
535 | * 'struct cache_deferred_req' | |
536 | * This cache_deferred_req contains a method to allow | |
537 | * it to be revisited when cache info is available | |
538 | */ | |
539 | ||
540 | #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) | |
541 | #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) | |
542 | ||
543 | #define DFR_MAX 300 /* ??? */ | |
544 | ||
545 | static DEFINE_SPINLOCK(cache_defer_lock); | |
546 | static LIST_HEAD(cache_defer_list); | |
547 | static struct list_head cache_defer_hash[DFR_HASHSIZE]; | |
548 | static int cache_defer_cnt; | |
549 | ||
e0bb89ef | 550 | static int cache_defer_req(struct cache_req *req, struct cache_head *item) |
1da177e4 LT |
551 | { |
552 | struct cache_deferred_req *dreq; | |
553 | int hash = DFR_HASH(item); | |
554 | ||
01f3bd1f BF |
555 | if (cache_defer_cnt >= DFR_MAX) { |
556 | /* too much in the cache, randomly drop this one, | |
557 | * or continue and drop the oldest below | |
558 | */ | |
559 | if (net_random()&1) | |
560 | return -ETIMEDOUT; | |
561 | } | |
1da177e4 LT |
562 | dreq = req->defer(req); |
563 | if (dreq == NULL) | |
e0bb89ef | 564 | return -ETIMEDOUT; |
1da177e4 LT |
565 | |
566 | dreq->item = item; | |
1da177e4 LT |
567 | |
568 | spin_lock(&cache_defer_lock); | |
569 | ||
570 | list_add(&dreq->recent, &cache_defer_list); | |
571 | ||
572 | if (cache_defer_hash[hash].next == NULL) | |
573 | INIT_LIST_HEAD(&cache_defer_hash[hash]); | |
574 | list_add(&dreq->hash, &cache_defer_hash[hash]); | |
575 | ||
576 | /* it is in, now maybe clean up */ | |
577 | dreq = NULL; | |
578 | if (++cache_defer_cnt > DFR_MAX) { | |
01f3bd1f BF |
579 | dreq = list_entry(cache_defer_list.prev, |
580 | struct cache_deferred_req, recent); | |
1da177e4 LT |
581 | list_del(&dreq->recent); |
582 | list_del(&dreq->hash); | |
583 | cache_defer_cnt--; | |
584 | } | |
585 | spin_unlock(&cache_defer_lock); | |
586 | ||
587 | if (dreq) { | |
588 | /* there was one too many */ | |
589 | dreq->revisit(dreq, 1); | |
590 | } | |
4013edea | 591 | if (!test_bit(CACHE_PENDING, &item->flags)) { |
1da177e4 LT |
592 | /* must have just been validated... */ |
593 | cache_revisit_request(item); | |
594 | } | |
e0bb89ef | 595 | return 0; |
1da177e4 LT |
596 | } |
597 | ||
598 | static void cache_revisit_request(struct cache_head *item) | |
599 | { | |
600 | struct cache_deferred_req *dreq; | |
601 | struct list_head pending; | |
602 | ||
603 | struct list_head *lp; | |
604 | int hash = DFR_HASH(item); | |
605 | ||
606 | INIT_LIST_HEAD(&pending); | |
607 | spin_lock(&cache_defer_lock); | |
cca5172a | 608 | |
1da177e4 LT |
609 | lp = cache_defer_hash[hash].next; |
610 | if (lp) { | |
611 | while (lp != &cache_defer_hash[hash]) { | |
612 | dreq = list_entry(lp, struct cache_deferred_req, hash); | |
613 | lp = lp->next; | |
614 | if (dreq->item == item) { | |
615 | list_del(&dreq->hash); | |
616 | list_move(&dreq->recent, &pending); | |
617 | cache_defer_cnt--; | |
618 | } | |
619 | } | |
620 | } | |
621 | spin_unlock(&cache_defer_lock); | |
622 | ||
623 | while (!list_empty(&pending)) { | |
624 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); | |
625 | list_del_init(&dreq->recent); | |
626 | dreq->revisit(dreq, 0); | |
627 | } | |
628 | } | |
629 | ||
630 | void cache_clean_deferred(void *owner) | |
631 | { | |
632 | struct cache_deferred_req *dreq, *tmp; | |
633 | struct list_head pending; | |
634 | ||
635 | ||
636 | INIT_LIST_HEAD(&pending); | |
637 | spin_lock(&cache_defer_lock); | |
cca5172a | 638 | |
1da177e4 LT |
639 | list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { |
640 | if (dreq->owner == owner) { | |
641 | list_del(&dreq->hash); | |
642 | list_move(&dreq->recent, &pending); | |
643 | cache_defer_cnt--; | |
644 | } | |
645 | } | |
646 | spin_unlock(&cache_defer_lock); | |
647 | ||
648 | while (!list_empty(&pending)) { | |
649 | dreq = list_entry(pending.next, struct cache_deferred_req, recent); | |
650 | list_del_init(&dreq->recent); | |
651 | dreq->revisit(dreq, 1); | |
652 | } | |
653 | } | |
654 | ||
655 | /* | |
656 | * communicate with user-space | |
657 | * | |
a490c681 BF |
658 | * We have a magic /proc file - /proc/sunrpc/<cachename>/channel. |
659 | * On read, you get a full request, or block. | |
660 | * On write, an update request is processed. | |
661 | * Poll works if anything to read, and always allows write. | |
1da177e4 | 662 | * |
cca5172a | 663 | * Implemented by linked list of requests. Each open file has |
a490c681 | 664 | * a ->private that also exists in this list. New requests are added |
1da177e4 LT |
665 | * to the end and may wakeup and preceding readers. |
666 | * New readers are added to the head. If, on read, an item is found with | |
667 | * CACHE_UPCALLING clear, we free it from the list. | |
668 | * | |
669 | */ | |
670 | ||
671 | static DEFINE_SPINLOCK(queue_lock); | |
4a3e2f71 | 672 | static DEFINE_MUTEX(queue_io_mutex); |
1da177e4 LT |
673 | |
674 | struct cache_queue { | |
675 | struct list_head list; | |
676 | int reader; /* if 0, then request */ | |
677 | }; | |
678 | struct cache_request { | |
679 | struct cache_queue q; | |
680 | struct cache_head *item; | |
681 | char * buf; | |
682 | int len; | |
683 | int readers; | |
684 | }; | |
685 | struct cache_reader { | |
686 | struct cache_queue q; | |
687 | int offset; /* if non-0, we have a refcnt on next request */ | |
688 | }; | |
689 | ||
690 | static ssize_t | |
691 | cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
692 | { | |
693 | struct cache_reader *rp = filp->private_data; | |
694 | struct cache_request *rq; | |
303b46bb | 695 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
696 | int err; |
697 | ||
698 | if (count == 0) | |
699 | return 0; | |
700 | ||
4a3e2f71 | 701 | mutex_lock(&queue_io_mutex); /* protect against multiple concurrent |
1da177e4 LT |
702 | * readers on this file */ |
703 | again: | |
704 | spin_lock(&queue_lock); | |
705 | /* need to find next request */ | |
706 | while (rp->q.list.next != &cd->queue && | |
707 | list_entry(rp->q.list.next, struct cache_queue, list) | |
708 | ->reader) { | |
709 | struct list_head *next = rp->q.list.next; | |
710 | list_move(&rp->q.list, next); | |
711 | } | |
712 | if (rp->q.list.next == &cd->queue) { | |
713 | spin_unlock(&queue_lock); | |
4a3e2f71 | 714 | mutex_unlock(&queue_io_mutex); |
09a62660 | 715 | BUG_ON(rp->offset); |
1da177e4 LT |
716 | return 0; |
717 | } | |
718 | rq = container_of(rp->q.list.next, struct cache_request, q.list); | |
09a62660 | 719 | BUG_ON(rq->q.reader); |
1da177e4 LT |
720 | if (rp->offset == 0) |
721 | rq->readers++; | |
722 | spin_unlock(&queue_lock); | |
723 | ||
724 | if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { | |
725 | err = -EAGAIN; | |
726 | spin_lock(&queue_lock); | |
727 | list_move(&rp->q.list, &rq->q.list); | |
728 | spin_unlock(&queue_lock); | |
729 | } else { | |
730 | if (rp->offset + count > rq->len) | |
731 | count = rq->len - rp->offset; | |
732 | err = -EFAULT; | |
733 | if (copy_to_user(buf, rq->buf + rp->offset, count)) | |
734 | goto out; | |
735 | rp->offset += count; | |
736 | if (rp->offset >= rq->len) { | |
737 | rp->offset = 0; | |
738 | spin_lock(&queue_lock); | |
739 | list_move(&rp->q.list, &rq->q.list); | |
740 | spin_unlock(&queue_lock); | |
741 | } | |
742 | err = 0; | |
743 | } | |
744 | out: | |
745 | if (rp->offset == 0) { | |
746 | /* need to release rq */ | |
747 | spin_lock(&queue_lock); | |
748 | rq->readers--; | |
749 | if (rq->readers == 0 && | |
750 | !test_bit(CACHE_PENDING, &rq->item->flags)) { | |
751 | list_del(&rq->q.list); | |
752 | spin_unlock(&queue_lock); | |
baab935f | 753 | cache_put(rq->item, cd); |
1da177e4 LT |
754 | kfree(rq->buf); |
755 | kfree(rq); | |
756 | } else | |
757 | spin_unlock(&queue_lock); | |
758 | } | |
759 | if (err == -EAGAIN) | |
760 | goto again; | |
4a3e2f71 | 761 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
762 | return err ? err : count; |
763 | } | |
764 | ||
4a3e2f71 | 765 | static char write_buf[8192]; /* protected by queue_io_mutex */ |
1da177e4 LT |
766 | |
767 | static ssize_t | |
768 | cache_write(struct file *filp, const char __user *buf, size_t count, | |
769 | loff_t *ppos) | |
770 | { | |
771 | int err; | |
303b46bb | 772 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
773 | |
774 | if (count == 0) | |
775 | return 0; | |
776 | if (count >= sizeof(write_buf)) | |
777 | return -EINVAL; | |
778 | ||
4a3e2f71 | 779 | mutex_lock(&queue_io_mutex); |
1da177e4 LT |
780 | |
781 | if (copy_from_user(write_buf, buf, count)) { | |
4a3e2f71 | 782 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
783 | return -EFAULT; |
784 | } | |
785 | write_buf[count] = '\0'; | |
786 | if (cd->cache_parse) | |
787 | err = cd->cache_parse(cd, write_buf, count); | |
788 | else | |
789 | err = -EINVAL; | |
790 | ||
4a3e2f71 | 791 | mutex_unlock(&queue_io_mutex); |
1da177e4 LT |
792 | return err ? err : count; |
793 | } | |
794 | ||
795 | static DECLARE_WAIT_QUEUE_HEAD(queue_wait); | |
796 | ||
797 | static unsigned int | |
798 | cache_poll(struct file *filp, poll_table *wait) | |
799 | { | |
800 | unsigned int mask; | |
801 | struct cache_reader *rp = filp->private_data; | |
802 | struct cache_queue *cq; | |
303b46bb | 803 | struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; |
1da177e4 LT |
804 | |
805 | poll_wait(filp, &queue_wait, wait); | |
806 | ||
807 | /* alway allow write */ | |
808 | mask = POLL_OUT | POLLWRNORM; | |
809 | ||
810 | if (!rp) | |
811 | return mask; | |
812 | ||
813 | spin_lock(&queue_lock); | |
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 | mask |= POLLIN | POLLRDNORM; | |
819 | break; | |
820 | } | |
821 | spin_unlock(&queue_lock); | |
822 | return mask; | |
823 | } | |
824 | ||
825 | static int | |
826 | cache_ioctl(struct inode *ino, struct file *filp, | |
827 | unsigned int cmd, unsigned long arg) | |
828 | { | |
829 | int len = 0; | |
830 | struct cache_reader *rp = filp->private_data; | |
831 | struct cache_queue *cq; | |
832 | struct cache_detail *cd = PDE(ino)->data; | |
833 | ||
834 | if (cmd != FIONREAD || !rp) | |
835 | return -EINVAL; | |
836 | ||
837 | spin_lock(&queue_lock); | |
838 | ||
839 | /* only find the length remaining in current request, | |
840 | * or the length of the next request | |
841 | */ | |
842 | for (cq= &rp->q; &cq->list != &cd->queue; | |
843 | cq = list_entry(cq->list.next, struct cache_queue, list)) | |
844 | if (!cq->reader) { | |
845 | struct cache_request *cr = | |
846 | container_of(cq, struct cache_request, q); | |
847 | len = cr->len - rp->offset; | |
848 | break; | |
849 | } | |
850 | spin_unlock(&queue_lock); | |
851 | ||
852 | return put_user(len, (int __user *)arg); | |
853 | } | |
854 | ||
855 | static int | |
856 | cache_open(struct inode *inode, struct file *filp) | |
857 | { | |
858 | struct cache_reader *rp = NULL; | |
859 | ||
860 | nonseekable_open(inode, filp); | |
861 | if (filp->f_mode & FMODE_READ) { | |
862 | struct cache_detail *cd = PDE(inode)->data; | |
863 | ||
864 | rp = kmalloc(sizeof(*rp), GFP_KERNEL); | |
865 | if (!rp) | |
866 | return -ENOMEM; | |
867 | rp->offset = 0; | |
868 | rp->q.reader = 1; | |
869 | atomic_inc(&cd->readers); | |
870 | spin_lock(&queue_lock); | |
871 | list_add(&rp->q.list, &cd->queue); | |
872 | spin_unlock(&queue_lock); | |
873 | } | |
874 | filp->private_data = rp; | |
875 | return 0; | |
876 | } | |
877 | ||
878 | static int | |
879 | cache_release(struct inode *inode, struct file *filp) | |
880 | { | |
881 | struct cache_reader *rp = filp->private_data; | |
882 | struct cache_detail *cd = PDE(inode)->data; | |
883 | ||
884 | if (rp) { | |
885 | spin_lock(&queue_lock); | |
886 | if (rp->offset) { | |
887 | struct cache_queue *cq; | |
888 | for (cq= &rp->q; &cq->list != &cd->queue; | |
889 | cq = list_entry(cq->list.next, struct cache_queue, list)) | |
890 | if (!cq->reader) { | |
891 | container_of(cq, struct cache_request, q) | |
892 | ->readers--; | |
893 | break; | |
894 | } | |
895 | rp->offset = 0; | |
896 | } | |
897 | list_del(&rp->q.list); | |
898 | spin_unlock(&queue_lock); | |
899 | ||
900 | filp->private_data = NULL; | |
901 | kfree(rp); | |
902 | ||
903 | cd->last_close = get_seconds(); | |
904 | atomic_dec(&cd->readers); | |
905 | } | |
906 | return 0; | |
907 | } | |
908 | ||
909 | ||
910 | ||
da7071d7 | 911 | static const struct file_operations cache_file_operations = { |
1da177e4 LT |
912 | .owner = THIS_MODULE, |
913 | .llseek = no_llseek, | |
914 | .read = cache_read, | |
915 | .write = cache_write, | |
916 | .poll = cache_poll, | |
917 | .ioctl = cache_ioctl, /* for FIONREAD */ | |
918 | .open = cache_open, | |
919 | .release = cache_release, | |
920 | }; | |
921 | ||
922 | ||
923 | static void queue_loose(struct cache_detail *detail, struct cache_head *ch) | |
924 | { | |
925 | struct cache_queue *cq; | |
926 | spin_lock(&queue_lock); | |
927 | list_for_each_entry(cq, &detail->queue, list) | |
928 | if (!cq->reader) { | |
929 | struct cache_request *cr = container_of(cq, struct cache_request, q); | |
930 | if (cr->item != ch) | |
931 | continue; | |
932 | if (cr->readers != 0) | |
4013edea | 933 | continue; |
1da177e4 LT |
934 | list_del(&cr->q.list); |
935 | spin_unlock(&queue_lock); | |
baab935f | 936 | cache_put(cr->item, detail); |
1da177e4 LT |
937 | kfree(cr->buf); |
938 | kfree(cr); | |
939 | return; | |
940 | } | |
941 | spin_unlock(&queue_lock); | |
942 | } | |
943 | ||
944 | /* | |
945 | * Support routines for text-based upcalls. | |
946 | * Fields are separated by spaces. | |
947 | * Fields are either mangled to quote space tab newline slosh with slosh | |
948 | * or a hexified with a leading \x | |
949 | * Record is terminated with newline. | |
950 | * | |
951 | */ | |
952 | ||
953 | void qword_add(char **bpp, int *lp, char *str) | |
954 | { | |
955 | char *bp = *bpp; | |
956 | int len = *lp; | |
957 | char c; | |
958 | ||
959 | if (len < 0) return; | |
960 | ||
961 | while ((c=*str++) && len) | |
962 | switch(c) { | |
963 | case ' ': | |
964 | case '\t': | |
965 | case '\n': | |
966 | case '\\': | |
967 | if (len >= 4) { | |
968 | *bp++ = '\\'; | |
969 | *bp++ = '0' + ((c & 0300)>>6); | |
970 | *bp++ = '0' + ((c & 0070)>>3); | |
971 | *bp++ = '0' + ((c & 0007)>>0); | |
972 | } | |
973 | len -= 4; | |
974 | break; | |
975 | default: | |
976 | *bp++ = c; | |
977 | len--; | |
978 | } | |
979 | if (c || len <1) len = -1; | |
980 | else { | |
981 | *bp++ = ' '; | |
982 | len--; | |
983 | } | |
984 | *bpp = bp; | |
985 | *lp = len; | |
986 | } | |
24c3767e | 987 | EXPORT_SYMBOL_GPL(qword_add); |
1da177e4 LT |
988 | |
989 | void qword_addhex(char **bpp, int *lp, char *buf, int blen) | |
990 | { | |
991 | char *bp = *bpp; | |
992 | int len = *lp; | |
993 | ||
994 | if (len < 0) return; | |
995 | ||
996 | if (len > 2) { | |
997 | *bp++ = '\\'; | |
998 | *bp++ = 'x'; | |
999 | len -= 2; | |
1000 | while (blen && len >= 2) { | |
1001 | unsigned char c = *buf++; | |
1002 | *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); | |
1003 | *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); | |
1004 | len -= 2; | |
1005 | blen--; | |
1006 | } | |
1007 | } | |
1008 | if (blen || len<1) len = -1; | |
1009 | else { | |
1010 | *bp++ = ' '; | |
1011 | len--; | |
1012 | } | |
1013 | *bpp = bp; | |
1014 | *lp = len; | |
1015 | } | |
24c3767e | 1016 | EXPORT_SYMBOL_GPL(qword_addhex); |
1da177e4 LT |
1017 | |
1018 | static void warn_no_listener(struct cache_detail *detail) | |
1019 | { | |
1020 | if (detail->last_warn != detail->last_close) { | |
1021 | detail->last_warn = detail->last_close; | |
1022 | if (detail->warn_no_listener) | |
1023 | detail->warn_no_listener(detail); | |
1024 | } | |
1025 | } | |
1026 | ||
1027 | /* | |
1028 | * register an upcall request to user-space. | |
1029 | * Each request is at most one page long. | |
1030 | */ | |
1031 | static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) | |
1032 | { | |
1033 | ||
1034 | char *buf; | |
1035 | struct cache_request *crq; | |
1036 | char *bp; | |
1037 | int len; | |
1038 | ||
1039 | if (detail->cache_request == NULL) | |
1040 | return -EINVAL; | |
1041 | ||
1042 | if (atomic_read(&detail->readers) == 0 && | |
1043 | detail->last_close < get_seconds() - 30) { | |
1044 | warn_no_listener(detail); | |
1045 | return -EINVAL; | |
1046 | } | |
1047 | ||
1048 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
1049 | if (!buf) | |
1050 | return -EAGAIN; | |
1051 | ||
1052 | crq = kmalloc(sizeof (*crq), GFP_KERNEL); | |
1053 | if (!crq) { | |
1054 | kfree(buf); | |
1055 | return -EAGAIN; | |
1056 | } | |
1057 | ||
1058 | bp = buf; len = PAGE_SIZE; | |
1059 | ||
1060 | detail->cache_request(detail, h, &bp, &len); | |
1061 | ||
1062 | if (len < 0) { | |
1063 | kfree(buf); | |
1064 | kfree(crq); | |
1065 | return -EAGAIN; | |
1066 | } | |
1067 | crq->q.reader = 0; | |
1068 | crq->item = cache_get(h); | |
1069 | crq->buf = buf; | |
1070 | crq->len = PAGE_SIZE - len; | |
1071 | crq->readers = 0; | |
1072 | spin_lock(&queue_lock); | |
1073 | list_add_tail(&crq->q.list, &detail->queue); | |
1074 | spin_unlock(&queue_lock); | |
1075 | wake_up(&queue_wait); | |
1076 | return 0; | |
1077 | } | |
1078 | ||
1079 | /* | |
1080 | * parse a message from user-space and pass it | |
1081 | * to an appropriate cache | |
1082 | * Messages are, like requests, separated into fields by | |
1083 | * spaces and dequotes as \xHEXSTRING or embedded \nnn octal | |
1084 | * | |
cca5172a | 1085 | * Message is |
1da177e4 LT |
1086 | * reply cachename expiry key ... content.... |
1087 | * | |
cca5172a | 1088 | * key and content are both parsed by cache |
1da177e4 LT |
1089 | */ |
1090 | ||
1091 | #define isodigit(c) (isdigit(c) && c <= '7') | |
1092 | int qword_get(char **bpp, char *dest, int bufsize) | |
1093 | { | |
1094 | /* return bytes copied, or -1 on error */ | |
1095 | char *bp = *bpp; | |
1096 | int len = 0; | |
1097 | ||
1098 | while (*bp == ' ') bp++; | |
1099 | ||
1100 | if (bp[0] == '\\' && bp[1] == 'x') { | |
1101 | /* HEX STRING */ | |
1102 | bp += 2; | |
1103 | while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { | |
1104 | int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; | |
1105 | bp++; | |
1106 | byte <<= 4; | |
1107 | byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; | |
1108 | *dest++ = byte; | |
1109 | bp++; | |
1110 | len++; | |
1111 | } | |
1112 | } else { | |
1113 | /* text with \nnn octal quoting */ | |
1114 | while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { | |
1115 | if (*bp == '\\' && | |
1116 | isodigit(bp[1]) && (bp[1] <= '3') && | |
1117 | isodigit(bp[2]) && | |
1118 | isodigit(bp[3])) { | |
1119 | int byte = (*++bp -'0'); | |
1120 | bp++; | |
1121 | byte = (byte << 3) | (*bp++ - '0'); | |
1122 | byte = (byte << 3) | (*bp++ - '0'); | |
1123 | *dest++ = byte; | |
1124 | len++; | |
1125 | } else { | |
1126 | *dest++ = *bp++; | |
1127 | len++; | |
1128 | } | |
1129 | } | |
1130 | } | |
1131 | ||
1132 | if (*bp != ' ' && *bp != '\n' && *bp != '\0') | |
1133 | return -1; | |
1134 | while (*bp == ' ') bp++; | |
1135 | *bpp = bp; | |
1136 | *dest = '\0'; | |
1137 | return len; | |
1138 | } | |
24c3767e | 1139 | EXPORT_SYMBOL_GPL(qword_get); |
1da177e4 LT |
1140 | |
1141 | ||
1142 | /* | |
1143 | * support /proc/sunrpc/cache/$CACHENAME/content | |
1144 | * as a seqfile. | |
1145 | * We call ->cache_show passing NULL for the item to | |
1146 | * get a header, then pass each real item in the cache | |
1147 | */ | |
1148 | ||
1149 | struct handle { | |
1150 | struct cache_detail *cd; | |
1151 | }; | |
1152 | ||
1153 | static void *c_start(struct seq_file *m, loff_t *pos) | |
9a429c49 | 1154 | __acquires(cd->hash_lock) |
1da177e4 LT |
1155 | { |
1156 | loff_t n = *pos; | |
1157 | unsigned hash, entry; | |
1158 | struct cache_head *ch; | |
1159 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
cca5172a | 1160 | |
1da177e4 LT |
1161 | |
1162 | read_lock(&cd->hash_lock); | |
1163 | if (!n--) | |
1164 | return SEQ_START_TOKEN; | |
1165 | hash = n >> 32; | |
1166 | entry = n & ((1LL<<32) - 1); | |
1167 | ||
1168 | for (ch=cd->hash_table[hash]; ch; ch=ch->next) | |
1169 | if (!entry--) | |
1170 | return ch; | |
1171 | n &= ~((1LL<<32) - 1); | |
1172 | do { | |
1173 | hash++; | |
1174 | n += 1LL<<32; | |
cca5172a | 1175 | } while(hash < cd->hash_size && |
1da177e4 LT |
1176 | cd->hash_table[hash]==NULL); |
1177 | if (hash >= cd->hash_size) | |
1178 | return NULL; | |
1179 | *pos = n+1; | |
1180 | return cd->hash_table[hash]; | |
1181 | } | |
1182 | ||
1183 | static void *c_next(struct seq_file *m, void *p, loff_t *pos) | |
1184 | { | |
1185 | struct cache_head *ch = p; | |
1186 | int hash = (*pos >> 32); | |
1187 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1188 | ||
1189 | if (p == SEQ_START_TOKEN) | |
1190 | hash = 0; | |
1191 | else if (ch->next == NULL) { | |
1192 | hash++; | |
1193 | *pos += 1LL<<32; | |
1194 | } else { | |
1195 | ++*pos; | |
1196 | return ch->next; | |
1197 | } | |
1198 | *pos &= ~((1LL<<32) - 1); | |
1199 | while (hash < cd->hash_size && | |
1200 | cd->hash_table[hash] == NULL) { | |
1201 | hash++; | |
1202 | *pos += 1LL<<32; | |
1203 | } | |
1204 | if (hash >= cd->hash_size) | |
1205 | return NULL; | |
1206 | ++*pos; | |
1207 | return cd->hash_table[hash]; | |
1208 | } | |
1209 | ||
1210 | static void c_stop(struct seq_file *m, void *p) | |
9a429c49 | 1211 | __releases(cd->hash_lock) |
1da177e4 LT |
1212 | { |
1213 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1214 | read_unlock(&cd->hash_lock); | |
1215 | } | |
1216 | ||
1217 | static int c_show(struct seq_file *m, void *p) | |
1218 | { | |
1219 | struct cache_head *cp = p; | |
1220 | struct cache_detail *cd = ((struct handle*)m->private)->cd; | |
1221 | ||
1222 | if (p == SEQ_START_TOKEN) | |
1223 | return cd->cache_show(m, cd, NULL); | |
1224 | ||
1225 | ifdebug(CACHE) | |
4013edea | 1226 | seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", |
baab935f | 1227 | cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); |
1da177e4 LT |
1228 | cache_get(cp); |
1229 | if (cache_check(cd, cp, NULL)) | |
1230 | /* cache_check does a cache_put on failure */ | |
1231 | seq_printf(m, "# "); | |
1232 | else | |
1233 | cache_put(cp, cd); | |
1234 | ||
1235 | return cd->cache_show(m, cd, cp); | |
1236 | } | |
1237 | ||
56b3d975 | 1238 | static const struct seq_operations cache_content_op = { |
1da177e4 LT |
1239 | .start = c_start, |
1240 | .next = c_next, | |
1241 | .stop = c_stop, | |
1242 | .show = c_show, | |
1243 | }; | |
1244 | ||
1245 | static int content_open(struct inode *inode, struct file *file) | |
1246 | { | |
1da177e4 LT |
1247 | struct handle *han; |
1248 | struct cache_detail *cd = PDE(inode)->data; | |
1249 | ||
ec931035 | 1250 | han = __seq_open_private(file, &cache_content_op, sizeof(*han)); |
1da177e4 LT |
1251 | if (han == NULL) |
1252 | return -ENOMEM; | |
1253 | ||
1254 | han->cd = cd; | |
ec931035 | 1255 | return 0; |
1da177e4 | 1256 | } |
1da177e4 | 1257 | |
da7071d7 | 1258 | static const struct file_operations content_file_operations = { |
1da177e4 LT |
1259 | .open = content_open, |
1260 | .read = seq_read, | |
1261 | .llseek = seq_lseek, | |
14690fc6 | 1262 | .release = seq_release_private, |
1da177e4 LT |
1263 | }; |
1264 | ||
1265 | static ssize_t read_flush(struct file *file, char __user *buf, | |
1266 | size_t count, loff_t *ppos) | |
1267 | { | |
303b46bb | 1268 | struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; |
1da177e4 LT |
1269 | char tbuf[20]; |
1270 | unsigned long p = *ppos; | |
01b2969a | 1271 | size_t len; |
1da177e4 LT |
1272 | |
1273 | sprintf(tbuf, "%lu\n", cd->flush_time); | |
1274 | len = strlen(tbuf); | |
1275 | if (p >= len) | |
1276 | return 0; | |
1277 | len -= p; | |
01b2969a CL |
1278 | if (len > count) |
1279 | len = count; | |
1da177e4 | 1280 | if (copy_to_user(buf, (void*)(tbuf+p), len)) |
01b2969a CL |
1281 | return -EFAULT; |
1282 | *ppos += len; | |
1da177e4 LT |
1283 | return len; |
1284 | } | |
1285 | ||
1286 | static ssize_t write_flush(struct file * file, const char __user * buf, | |
1287 | size_t count, loff_t *ppos) | |
1288 | { | |
303b46bb | 1289 | struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; |
1da177e4 LT |
1290 | char tbuf[20]; |
1291 | char *ep; | |
1292 | long flushtime; | |
1293 | if (*ppos || count > sizeof(tbuf)-1) | |
1294 | return -EINVAL; | |
1295 | if (copy_from_user(tbuf, buf, count)) | |
1296 | return -EFAULT; | |
1297 | tbuf[count] = 0; | |
1298 | flushtime = simple_strtoul(tbuf, &ep, 0); | |
1299 | if (*ep && *ep != '\n') | |
1300 | return -EINVAL; | |
1301 | ||
1302 | cd->flush_time = flushtime; | |
1303 | cd->nextcheck = get_seconds(); | |
1304 | cache_flush(); | |
1305 | ||
1306 | *ppos += count; | |
1307 | return count; | |
1308 | } | |
1309 | ||
da7071d7 | 1310 | static const struct file_operations cache_flush_operations = { |
1da177e4 LT |
1311 | .open = nonseekable_open, |
1312 | .read = read_flush, | |
1313 | .write = write_flush, | |
1314 | }; |