blob: c9966713282a75531388b9d02e408aafef62f933 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * net/sunrpc/cache.c
3 *
4 * Generic code for various authentication-related caches
5 * used by sunrpc clients and servers.
6 *
7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
8 *
9 * Released under terms in GPL version 2. See COPYING.
10 *
11 */
12
13#include <linux/types.h>
14#include <linux/fs.h>
15#include <linux/file.h>
16#include <linux/slab.h>
17#include <linux/signal.h>
18#include <linux/sched.h>
19#include <linux/kmod.h>
20#include <linux/list.h>
21#include <linux/module.h>
22#include <linux/ctype.h>
23#include <asm/uaccess.h>
24#include <linux/poll.h>
25#include <linux/seq_file.h>
26#include <linux/proc_fs.h>
27#include <linux/net.h>
28#include <linux/workqueue.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080029#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <asm/ioctls.h>
31#include <linux/sunrpc/types.h>
32#include <linux/sunrpc/cache.h>
33#include <linux/sunrpc/stats.h>
34
35#define RPCDBG_FACILITY RPCDBG_CACHE
36
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -080037static int cache_defer_req(struct cache_req *req, struct cache_head *item);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static void cache_revisit_request(struct cache_head *item);
39
Adrian Bunk74cae612006-03-27 01:15:10 -080040static void cache_init(struct cache_head *h)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
42 time_t now = get_seconds();
43 h->next = NULL;
44 h->flags = 0;
NeilBrownbaab9352006-03-27 01:15:09 -080045 kref_init(&h->ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 h->expiry_time = now + CACHE_NEW_EXPIRY;
47 h->last_refresh = now;
48}
49
NeilBrown15a5f6b2006-03-27 01:15:02 -080050struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
51 struct cache_head *key, int hash)
52{
53 struct cache_head **head, **hp;
54 struct cache_head *new = NULL;
55
56 head = &detail->hash_table[hash];
57
58 read_lock(&detail->hash_lock);
59
60 for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
61 struct cache_head *tmp = *hp;
62 if (detail->match(tmp, key)) {
63 cache_get(tmp);
64 read_unlock(&detail->hash_lock);
65 return tmp;
66 }
67 }
68 read_unlock(&detail->hash_lock);
69 /* Didn't find anything, insert an empty entry */
70
71 new = detail->alloc();
72 if (!new)
73 return NULL;
Neil Brown2f349312006-08-05 12:14:29 -070074 /* must fully initialise 'new', else
75 * we might get lose if we need to
76 * cache_put it soon.
77 */
NeilBrown15a5f6b2006-03-27 01:15:02 -080078 cache_init(new);
Neil Brown2f349312006-08-05 12:14:29 -070079 detail->init(new, key);
NeilBrown15a5f6b2006-03-27 01:15:02 -080080
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);
NeilBrownbaab9352006-03-27 01:15:09 -080089 cache_put(new, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -080090 return tmp;
91 }
92 }
NeilBrown15a5f6b2006-03-27 01:15:02 -080093 new->next = *head;
94 *head = new;
95 detail->entries++;
96 cache_get(new);
97 write_unlock(&detail->hash_lock);
98
99 return new;
100}
101EXPORT_SYMBOL(sunrpc_cache_lookup);
102
NeilBrownebd0cb12006-03-27 01:15:08 -0800103
104static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
105
106static 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
113static 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
NeilBrown15a5f6b2006-03-27 01:15:02 -0800124struct 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;
NeilBrownebd0cb12006-03-27 01:15:08 -0800133 int is_new;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800134
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);
NeilBrownebd0cb12006-03-27 01:15:08 -0800142 is_new = cache_fresh_locked(old, new->expiry_time);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800143 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800144 cache_fresh_unlocked(old, detail, is_new);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800145 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) {
NeilBrownbaab9352006-03-27 01:15:09 -0800152 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800153 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;
NeilBrownf2d39582006-05-22 22:35:25 -0700166 detail->entries++;
NeilBrown15a5f6b2006-03-27 01:15:02 -0800167 cache_get(tmp);
NeilBrownebd0cb12006-03-27 01:15:08 -0800168 is_new = cache_fresh_locked(tmp, new->expiry_time);
169 cache_fresh_locked(old, 0);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800170 write_unlock(&detail->hash_lock);
NeilBrownebd0cb12006-03-27 01:15:08 -0800171 cache_fresh_unlocked(tmp, detail, is_new);
172 cache_fresh_unlocked(old, detail, 0);
NeilBrownbaab9352006-03-27 01:15:09 -0800173 cache_put(old, detail);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800174 return tmp;
175}
176EXPORT_SYMBOL(sunrpc_cache_update);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
178static 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,
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800188 * -ETIMEDOUT if upcall failed and should be retried,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 * -ENOENT if cache entry was negative
190 */
191int 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) {
Chuck Lever46121cf2007-01-31 12:14:08 -0500218 dprintk("RPC: Want update, refage=%ld, age=%ld\n",
219 refresh_age, age);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 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);
NeilBrownebd0cb12006-03-27 01:15:08 -0800226 cache_fresh_unlocked(h, detail,
227 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 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)
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800241 if (cache_defer_req(rqstp, h) != 0)
242 rv = -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
NeilBrown4013ede2006-03-27 01:15:07 -0800244 if (rv)
NeilBrownbaab9352006-03-27 01:15:09 -0800245 cache_put(h, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 return rv;
247}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400248EXPORT_SYMBOL(cache_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250/*
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.
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800279 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 */
281
282static LIST_HEAD(cache_list);
283static DEFINE_SPINLOCK(cache_list_lock);
284static struct cache_detail *current_detail;
285static int current_index;
286
Arjan van de Venda7071d2007-02-12 00:55:36 -0800287static const struct file_operations cache_file_operations;
288static const struct file_operations content_file_operations;
289static const struct file_operations cache_flush_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
David Howells65f27f32006-11-22 14:55:48 +0000291static void do_cache_clean(struct work_struct *work);
292static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500294static void remove_cache_proc_entries(struct cache_detail *cd)
295{
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}
307
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500308#ifdef CONFIG_PROC_FS
309static int create_cache_proc_entries(struct cache_detail *cd)
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500310{
311 struct proc_dir_entry *p;
312
313 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
314 if (cd->proc_ent == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500315 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500316 cd->proc_ent->owner = cd->owner;
317 cd->channel_ent = cd->content_ent = NULL;
318
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700319 p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
320 cd->proc_ent, &cache_flush_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500321 cd->flush_ent = p;
322 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500323 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500324 p->owner = cd->owner;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500325
326 if (cd->cache_request || cd->cache_parse) {
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700327 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
328 cd->proc_ent, &cache_file_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500329 cd->channel_ent = p;
330 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500331 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500332 p->owner = cd->owner;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500333 }
334 if (cd->cache_show) {
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700335 p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
336 cd->proc_ent, &content_file_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500337 cd->content_ent = p;
338 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500339 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500340 p->owner = cd->owner;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500341 }
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500342 return 0;
343out_nomem:
344 remove_cache_proc_entries(cd);
345 return -ENOMEM;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500346}
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500347#else /* CONFIG_PROC_FS */
348static int create_cache_proc_entries(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349{
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500350 return 0;
351}
352#endif
353
354int cache_register(struct cache_detail *cd)
355{
356 int ret;
357
358 ret = create_cache_proc_entries(cd);
359 if (ret)
360 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 rwlock_init(&cd->hash_lock);
362 INIT_LIST_HEAD(&cd->queue);
363 spin_lock(&cache_list_lock);
364 cd->nextcheck = 0;
365 cd->entries = 0;
366 atomic_set(&cd->readers, 0);
367 cd->last_close = 0;
368 cd->last_warn = -1;
369 list_add(&cd->others, &cache_list);
370 spin_unlock(&cache_list_lock);
371
372 /* start the cleaning process */
David Howells52bad642006-11-22 14:54:01 +0000373 schedule_delayed_work(&cache_cleaner, 0);
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500374 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400376EXPORT_SYMBOL(cache_register);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500378void cache_unregister(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379{
380 cache_purge(cd);
381 spin_lock(&cache_list_lock);
382 write_lock(&cd->hash_lock);
383 if (cd->entries || atomic_read(&cd->inuse)) {
384 write_unlock(&cd->hash_lock);
385 spin_unlock(&cache_list_lock);
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500386 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 }
388 if (current_detail == cd)
389 current_detail = NULL;
390 list_del_init(&cd->others);
391 write_unlock(&cd->hash_lock);
392 spin_unlock(&cache_list_lock);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500393 remove_cache_proc_entries(cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 if (list_empty(&cache_list)) {
395 /* module must be being unloaded so its safe to kill the worker */
Trond Myklebust4011cd92007-08-07 15:33:01 -0400396 cancel_delayed_work_sync(&cache_cleaner);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 }
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500398 return;
399out:
400 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400402EXPORT_SYMBOL(cache_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404/* clean cache tries to find something to clean
405 * and cleans it.
406 * It returns 1 if it cleaned something,
407 * 0 if it didn't find anything this time
408 * -1 if it fell off the end of the list.
409 */
410static int cache_clean(void)
411{
412 int rv = 0;
413 struct list_head *next;
414
415 spin_lock(&cache_list_lock);
416
417 /* find a suitable table if we don't already have one */
418 while (current_detail == NULL ||
419 current_index >= current_detail->hash_size) {
420 if (current_detail)
421 next = current_detail->others.next;
422 else
423 next = cache_list.next;
424 if (next == &cache_list) {
425 current_detail = NULL;
426 spin_unlock(&cache_list_lock);
427 return -1;
428 }
429 current_detail = list_entry(next, struct cache_detail, others);
430 if (current_detail->nextcheck > get_seconds())
431 current_index = current_detail->hash_size;
432 else {
433 current_index = 0;
434 current_detail->nextcheck = get_seconds()+30*60;
435 }
436 }
437
438 /* find a non-empty bucket in the table */
439 while (current_detail &&
440 current_index < current_detail->hash_size &&
441 current_detail->hash_table[current_index] == NULL)
442 current_index++;
443
444 /* find a cleanable entry in the bucket and clean it, or set to next bucket */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800445
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 if (current_detail && current_index < current_detail->hash_size) {
447 struct cache_head *ch, **cp;
448 struct cache_detail *d;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800449
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 write_lock(&current_detail->hash_lock);
451
452 /* Ok, now to clean this strand */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800453
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 cp = & current_detail->hash_table[current_index];
455 ch = *cp;
456 for (; ch; cp= & ch->next, ch= *cp) {
457 if (current_detail->nextcheck > ch->expiry_time)
458 current_detail->nextcheck = ch->expiry_time+1;
459 if (ch->expiry_time >= get_seconds()
460 && ch->last_refresh >= current_detail->flush_time
461 )
462 continue;
463 if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
464 queue_loose(current_detail, ch);
465
NeilBrownbaab9352006-03-27 01:15:09 -0800466 if (atomic_read(&ch->ref.refcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 break;
468 }
469 if (ch) {
470 *cp = ch->next;
471 ch->next = NULL;
472 current_detail->entries--;
473 rv = 1;
474 }
475 write_unlock(&current_detail->hash_lock);
476 d = current_detail;
477 if (!ch)
478 current_index ++;
479 spin_unlock(&cache_list_lock);
480 if (ch)
NeilBrownbaab9352006-03-27 01:15:09 -0800481 cache_put(ch, d);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 } else
483 spin_unlock(&cache_list_lock);
484
485 return rv;
486}
487
488/*
489 * We want to regularly clean the cache, so we need to schedule some work ...
490 */
David Howells65f27f32006-11-22 14:55:48 +0000491static void do_cache_clean(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492{
493 int delay = 5;
494 if (cache_clean() == -1)
495 delay = 30*HZ;
496
497 if (list_empty(&cache_list))
498 delay = 0;
499
500 if (delay)
501 schedule_delayed_work(&cache_cleaner, delay);
502}
503
504
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800505/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 * Clean all caches promptly. This just calls cache_clean
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800507 * repeatedly until we are sure that every cache has had a chance to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 * be fully cleaned
509 */
510void cache_flush(void)
511{
512 while (cache_clean() != -1)
513 cond_resched();
514 while (cache_clean() != -1)
515 cond_resched();
516}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400517EXPORT_SYMBOL(cache_flush);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518
519void cache_purge(struct cache_detail *detail)
520{
521 detail->flush_time = LONG_MAX;
522 detail->nextcheck = get_seconds();
523 cache_flush();
524 detail->flush_time = 1;
525}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400526EXPORT_SYMBOL(cache_purge);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
528
529/*
530 * Deferral and Revisiting of Requests.
531 *
532 * If a cache lookup finds a pending entry, we
533 * need to defer the request and revisit it later.
534 * All deferred requests are stored in a hash table,
535 * indexed by "struct cache_head *".
536 * As it may be wasteful to store a whole request
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800537 * structure, we allow the request to provide a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 * deferred form, which must contain a
539 * 'struct cache_deferred_req'
540 * This cache_deferred_req contains a method to allow
541 * it to be revisited when cache info is available
542 */
543
544#define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head))
545#define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
546
547#define DFR_MAX 300 /* ??? */
548
549static DEFINE_SPINLOCK(cache_defer_lock);
550static LIST_HEAD(cache_defer_list);
551static struct list_head cache_defer_hash[DFR_HASHSIZE];
552static int cache_defer_cnt;
553
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800554static int cache_defer_req(struct cache_req *req, struct cache_head *item)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555{
556 struct cache_deferred_req *dreq;
557 int hash = DFR_HASH(item);
558
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800559 if (cache_defer_cnt >= DFR_MAX) {
560 /* too much in the cache, randomly drop this one,
561 * or continue and drop the oldest below
562 */
563 if (net_random()&1)
564 return -ETIMEDOUT;
565 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 dreq = req->defer(req);
567 if (dreq == NULL)
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800568 return -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569
570 dreq->item = item;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
572 spin_lock(&cache_defer_lock);
573
574 list_add(&dreq->recent, &cache_defer_list);
575
576 if (cache_defer_hash[hash].next == NULL)
577 INIT_LIST_HEAD(&cache_defer_hash[hash]);
578 list_add(&dreq->hash, &cache_defer_hash[hash]);
579
580 /* it is in, now maybe clean up */
581 dreq = NULL;
582 if (++cache_defer_cnt > DFR_MAX) {
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800583 dreq = list_entry(cache_defer_list.prev,
584 struct cache_deferred_req, recent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 list_del(&dreq->recent);
586 list_del(&dreq->hash);
587 cache_defer_cnt--;
588 }
589 spin_unlock(&cache_defer_lock);
590
591 if (dreq) {
592 /* there was one too many */
593 dreq->revisit(dreq, 1);
594 }
NeilBrown4013ede2006-03-27 01:15:07 -0800595 if (!test_bit(CACHE_PENDING, &item->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 /* must have just been validated... */
597 cache_revisit_request(item);
598 }
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800599 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600}
601
602static void cache_revisit_request(struct cache_head *item)
603{
604 struct cache_deferred_req *dreq;
605 struct list_head pending;
606
607 struct list_head *lp;
608 int hash = DFR_HASH(item);
609
610 INIT_LIST_HEAD(&pending);
611 spin_lock(&cache_defer_lock);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 lp = cache_defer_hash[hash].next;
614 if (lp) {
615 while (lp != &cache_defer_hash[hash]) {
616 dreq = list_entry(lp, struct cache_deferred_req, hash);
617 lp = lp->next;
618 if (dreq->item == item) {
619 list_del(&dreq->hash);
620 list_move(&dreq->recent, &pending);
621 cache_defer_cnt--;
622 }
623 }
624 }
625 spin_unlock(&cache_defer_lock);
626
627 while (!list_empty(&pending)) {
628 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
629 list_del_init(&dreq->recent);
630 dreq->revisit(dreq, 0);
631 }
632}
633
634void cache_clean_deferred(void *owner)
635{
636 struct cache_deferred_req *dreq, *tmp;
637 struct list_head pending;
638
639
640 INIT_LIST_HEAD(&pending);
641 spin_lock(&cache_defer_lock);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800642
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
644 if (dreq->owner == owner) {
645 list_del(&dreq->hash);
646 list_move(&dreq->recent, &pending);
647 cache_defer_cnt--;
648 }
649 }
650 spin_unlock(&cache_defer_lock);
651
652 while (!list_empty(&pending)) {
653 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
654 list_del_init(&dreq->recent);
655 dreq->revisit(dreq, 1);
656 }
657}
658
659/*
660 * communicate with user-space
661 *
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500662 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
663 * On read, you get a full request, or block.
664 * On write, an update request is processed.
665 * Poll works if anything to read, and always allows write.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800667 * Implemented by linked list of requests. Each open file has
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500668 * a ->private that also exists in this list. New requests are added
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 * to the end and may wakeup and preceding readers.
670 * New readers are added to the head. If, on read, an item is found with
671 * CACHE_UPCALLING clear, we free it from the list.
672 *
673 */
674
675static DEFINE_SPINLOCK(queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800676static DEFINE_MUTEX(queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677
678struct cache_queue {
679 struct list_head list;
680 int reader; /* if 0, then request */
681};
682struct cache_request {
683 struct cache_queue q;
684 struct cache_head *item;
685 char * buf;
686 int len;
687 int readers;
688};
689struct cache_reader {
690 struct cache_queue q;
691 int offset; /* if non-0, we have a refcnt on next request */
692};
693
694static ssize_t
695cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
696{
697 struct cache_reader *rp = filp->private_data;
698 struct cache_request *rq;
Josef Sipek303b46b2006-12-08 02:37:42 -0800699 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 int err;
701
702 if (count == 0)
703 return 0;
704
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800705 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 * readers on this file */
707 again:
708 spin_lock(&queue_lock);
709 /* need to find next request */
710 while (rp->q.list.next != &cd->queue &&
711 list_entry(rp->q.list.next, struct cache_queue, list)
712 ->reader) {
713 struct list_head *next = rp->q.list.next;
714 list_move(&rp->q.list, next);
715 }
716 if (rp->q.list.next == &cd->queue) {
717 spin_unlock(&queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800718 mutex_unlock(&queue_io_mutex);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800719 BUG_ON(rp->offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 return 0;
721 }
722 rq = container_of(rp->q.list.next, struct cache_request, q.list);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800723 BUG_ON(rq->q.reader);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 if (rp->offset == 0)
725 rq->readers++;
726 spin_unlock(&queue_lock);
727
728 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
729 err = -EAGAIN;
730 spin_lock(&queue_lock);
731 list_move(&rp->q.list, &rq->q.list);
732 spin_unlock(&queue_lock);
733 } else {
734 if (rp->offset + count > rq->len)
735 count = rq->len - rp->offset;
736 err = -EFAULT;
737 if (copy_to_user(buf, rq->buf + rp->offset, count))
738 goto out;
739 rp->offset += count;
740 if (rp->offset >= rq->len) {
741 rp->offset = 0;
742 spin_lock(&queue_lock);
743 list_move(&rp->q.list, &rq->q.list);
744 spin_unlock(&queue_lock);
745 }
746 err = 0;
747 }
748 out:
749 if (rp->offset == 0) {
750 /* need to release rq */
751 spin_lock(&queue_lock);
752 rq->readers--;
753 if (rq->readers == 0 &&
754 !test_bit(CACHE_PENDING, &rq->item->flags)) {
755 list_del(&rq->q.list);
756 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800757 cache_put(rq->item, cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 kfree(rq->buf);
759 kfree(rq);
760 } else
761 spin_unlock(&queue_lock);
762 }
763 if (err == -EAGAIN)
764 goto again;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800765 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 return err ? err : count;
767}
768
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800769static char write_buf[8192]; /* protected by queue_io_mutex */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
771static ssize_t
772cache_write(struct file *filp, const char __user *buf, size_t count,
773 loff_t *ppos)
774{
775 int err;
Josef Sipek303b46b2006-12-08 02:37:42 -0800776 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 if (count == 0)
779 return 0;
780 if (count >= sizeof(write_buf))
781 return -EINVAL;
782
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800783 mutex_lock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784
785 if (copy_from_user(write_buf, buf, count)) {
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800786 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 return -EFAULT;
788 }
789 write_buf[count] = '\0';
790 if (cd->cache_parse)
791 err = cd->cache_parse(cd, write_buf, count);
792 else
793 err = -EINVAL;
794
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800795 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 return err ? err : count;
797}
798
799static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
800
801static unsigned int
802cache_poll(struct file *filp, poll_table *wait)
803{
804 unsigned int mask;
805 struct cache_reader *rp = filp->private_data;
806 struct cache_queue *cq;
Josef Sipek303b46b2006-12-08 02:37:42 -0800807 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808
809 poll_wait(filp, &queue_wait, wait);
810
811 /* alway allow write */
812 mask = POLL_OUT | POLLWRNORM;
813
814 if (!rp)
815 return mask;
816
817 spin_lock(&queue_lock);
818
819 for (cq= &rp->q; &cq->list != &cd->queue;
820 cq = list_entry(cq->list.next, struct cache_queue, list))
821 if (!cq->reader) {
822 mask |= POLLIN | POLLRDNORM;
823 break;
824 }
825 spin_unlock(&queue_lock);
826 return mask;
827}
828
829static int
830cache_ioctl(struct inode *ino, struct file *filp,
831 unsigned int cmd, unsigned long arg)
832{
833 int len = 0;
834 struct cache_reader *rp = filp->private_data;
835 struct cache_queue *cq;
836 struct cache_detail *cd = PDE(ino)->data;
837
838 if (cmd != FIONREAD || !rp)
839 return -EINVAL;
840
841 spin_lock(&queue_lock);
842
843 /* only find the length remaining in current request,
844 * or the length of the next request
845 */
846 for (cq= &rp->q; &cq->list != &cd->queue;
847 cq = list_entry(cq->list.next, struct cache_queue, list))
848 if (!cq->reader) {
849 struct cache_request *cr =
850 container_of(cq, struct cache_request, q);
851 len = cr->len - rp->offset;
852 break;
853 }
854 spin_unlock(&queue_lock);
855
856 return put_user(len, (int __user *)arg);
857}
858
859static int
860cache_open(struct inode *inode, struct file *filp)
861{
862 struct cache_reader *rp = NULL;
863
864 nonseekable_open(inode, filp);
865 if (filp->f_mode & FMODE_READ) {
866 struct cache_detail *cd = PDE(inode)->data;
867
868 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
869 if (!rp)
870 return -ENOMEM;
871 rp->offset = 0;
872 rp->q.reader = 1;
873 atomic_inc(&cd->readers);
874 spin_lock(&queue_lock);
875 list_add(&rp->q.list, &cd->queue);
876 spin_unlock(&queue_lock);
877 }
878 filp->private_data = rp;
879 return 0;
880}
881
882static int
883cache_release(struct inode *inode, struct file *filp)
884{
885 struct cache_reader *rp = filp->private_data;
886 struct cache_detail *cd = PDE(inode)->data;
887
888 if (rp) {
889 spin_lock(&queue_lock);
890 if (rp->offset) {
891 struct cache_queue *cq;
892 for (cq= &rp->q; &cq->list != &cd->queue;
893 cq = list_entry(cq->list.next, struct cache_queue, list))
894 if (!cq->reader) {
895 container_of(cq, struct cache_request, q)
896 ->readers--;
897 break;
898 }
899 rp->offset = 0;
900 }
901 list_del(&rp->q.list);
902 spin_unlock(&queue_lock);
903
904 filp->private_data = NULL;
905 kfree(rp);
906
907 cd->last_close = get_seconds();
908 atomic_dec(&cd->readers);
909 }
910 return 0;
911}
912
913
914
Arjan van de Venda7071d2007-02-12 00:55:36 -0800915static const struct file_operations cache_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 .owner = THIS_MODULE,
917 .llseek = no_llseek,
918 .read = cache_read,
919 .write = cache_write,
920 .poll = cache_poll,
921 .ioctl = cache_ioctl, /* for FIONREAD */
922 .open = cache_open,
923 .release = cache_release,
924};
925
926
927static void queue_loose(struct cache_detail *detail, struct cache_head *ch)
928{
929 struct cache_queue *cq;
930 spin_lock(&queue_lock);
931 list_for_each_entry(cq, &detail->queue, list)
932 if (!cq->reader) {
933 struct cache_request *cr = container_of(cq, struct cache_request, q);
934 if (cr->item != ch)
935 continue;
936 if (cr->readers != 0)
NeilBrown4013ede2006-03-27 01:15:07 -0800937 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 list_del(&cr->q.list);
939 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800940 cache_put(cr->item, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 kfree(cr->buf);
942 kfree(cr);
943 return;
944 }
945 spin_unlock(&queue_lock);
946}
947
948/*
949 * Support routines for text-based upcalls.
950 * Fields are separated by spaces.
951 * Fields are either mangled to quote space tab newline slosh with slosh
952 * or a hexified with a leading \x
953 * Record is terminated with newline.
954 *
955 */
956
957void qword_add(char **bpp, int *lp, char *str)
958{
959 char *bp = *bpp;
960 int len = *lp;
961 char c;
962
963 if (len < 0) return;
964
965 while ((c=*str++) && len)
966 switch(c) {
967 case ' ':
968 case '\t':
969 case '\n':
970 case '\\':
971 if (len >= 4) {
972 *bp++ = '\\';
973 *bp++ = '0' + ((c & 0300)>>6);
974 *bp++ = '0' + ((c & 0070)>>3);
975 *bp++ = '0' + ((c & 0007)>>0);
976 }
977 len -= 4;
978 break;
979 default:
980 *bp++ = c;
981 len--;
982 }
983 if (c || len <1) len = -1;
984 else {
985 *bp++ = ' ';
986 len--;
987 }
988 *bpp = bp;
989 *lp = len;
990}
Trond Myklebustd2f7e792007-07-14 15:39:58 -0400991EXPORT_SYMBOL(qword_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
993void qword_addhex(char **bpp, int *lp, char *buf, int blen)
994{
995 char *bp = *bpp;
996 int len = *lp;
997
998 if (len < 0) return;
999
1000 if (len > 2) {
1001 *bp++ = '\\';
1002 *bp++ = 'x';
1003 len -= 2;
1004 while (blen && len >= 2) {
1005 unsigned char c = *buf++;
1006 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1007 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1008 len -= 2;
1009 blen--;
1010 }
1011 }
1012 if (blen || len<1) len = -1;
1013 else {
1014 *bp++ = ' ';
1015 len--;
1016 }
1017 *bpp = bp;
1018 *lp = len;
1019}
Trond Myklebustd2f7e792007-07-14 15:39:58 -04001020EXPORT_SYMBOL(qword_addhex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021
1022static 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 */
1035static 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 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001089 * Message is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 * reply cachename expiry key ... content....
1091 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001092 * key and content are both parsed by cache
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 */
1094
1095#define isodigit(c) (isdigit(c) && c <= '7')
1096int 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}
Trond Myklebustd2f7e792007-07-14 15:39:58 -04001143EXPORT_SYMBOL(qword_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144
1145
1146/*
1147 * support /proc/sunrpc/cache/$CACHENAME/content
1148 * as a seqfile.
1149 * We call ->cache_show passing NULL for the item to
1150 * get a header, then pass each real item in the cache
1151 */
1152
1153struct handle {
1154 struct cache_detail *cd;
1155};
1156
1157static void *c_start(struct seq_file *m, loff_t *pos)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001158 __acquires(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159{
1160 loff_t n = *pos;
1161 unsigned hash, entry;
1162 struct cache_head *ch;
1163 struct cache_detail *cd = ((struct handle*)m->private)->cd;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001164
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165
1166 read_lock(&cd->hash_lock);
1167 if (!n--)
1168 return SEQ_START_TOKEN;
1169 hash = n >> 32;
1170 entry = n & ((1LL<<32) - 1);
1171
1172 for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1173 if (!entry--)
1174 return ch;
1175 n &= ~((1LL<<32) - 1);
1176 do {
1177 hash++;
1178 n += 1LL<<32;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001179 } while(hash < cd->hash_size &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 cd->hash_table[hash]==NULL);
1181 if (hash >= cd->hash_size)
1182 return NULL;
1183 *pos = n+1;
1184 return cd->hash_table[hash];
1185}
1186
1187static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1188{
1189 struct cache_head *ch = p;
1190 int hash = (*pos >> 32);
1191 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1192
1193 if (p == SEQ_START_TOKEN)
1194 hash = 0;
1195 else if (ch->next == NULL) {
1196 hash++;
1197 *pos += 1LL<<32;
1198 } else {
1199 ++*pos;
1200 return ch->next;
1201 }
1202 *pos &= ~((1LL<<32) - 1);
1203 while (hash < cd->hash_size &&
1204 cd->hash_table[hash] == NULL) {
1205 hash++;
1206 *pos += 1LL<<32;
1207 }
1208 if (hash >= cd->hash_size)
1209 return NULL;
1210 ++*pos;
1211 return cd->hash_table[hash];
1212}
1213
1214static void c_stop(struct seq_file *m, void *p)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001215 __releases(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216{
1217 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1218 read_unlock(&cd->hash_lock);
1219}
1220
1221static int c_show(struct seq_file *m, void *p)
1222{
1223 struct cache_head *cp = p;
1224 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1225
1226 if (p == SEQ_START_TOKEN)
1227 return cd->cache_show(m, cd, NULL);
1228
1229 ifdebug(CACHE)
NeilBrown4013ede2006-03-27 01:15:07 -08001230 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
NeilBrownbaab9352006-03-27 01:15:09 -08001231 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 cache_get(cp);
1233 if (cache_check(cd, cp, NULL))
1234 /* cache_check does a cache_put on failure */
1235 seq_printf(m, "# ");
1236 else
1237 cache_put(cp, cd);
1238
1239 return cd->cache_show(m, cd, cp);
1240}
1241
Philippe De Muyter56b3d972007-07-10 23:07:31 -07001242static const struct seq_operations cache_content_op = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 .start = c_start,
1244 .next = c_next,
1245 .stop = c_stop,
1246 .show = c_show,
1247};
1248
1249static int content_open(struct inode *inode, struct file *file)
1250{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 struct handle *han;
1252 struct cache_detail *cd = PDE(inode)->data;
1253
Pavel Emelyanovec931032007-10-10 02:31:07 -07001254 han = __seq_open_private(file, &cache_content_op, sizeof(*han));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 if (han == NULL)
1256 return -ENOMEM;
1257
1258 han->cd = cd;
Pavel Emelyanovec931032007-10-10 02:31:07 -07001259 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
Arjan van de Venda7071d2007-02-12 00:55:36 -08001262static const struct file_operations content_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 .open = content_open,
1264 .read = seq_read,
1265 .llseek = seq_lseek,
Martin Peschke14690fc2007-04-26 01:03:43 -07001266 .release = seq_release_private,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267};
1268
1269static ssize_t read_flush(struct file *file, char __user *buf,
1270 size_t count, loff_t *ppos)
1271{
Josef Sipek303b46b2006-12-08 02:37:42 -08001272 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 char tbuf[20];
1274 unsigned long p = *ppos;
Chuck Lever01b29692007-10-26 13:31:20 -04001275 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276
1277 sprintf(tbuf, "%lu\n", cd->flush_time);
1278 len = strlen(tbuf);
1279 if (p >= len)
1280 return 0;
1281 len -= p;
Chuck Lever01b29692007-10-26 13:31:20 -04001282 if (len > count)
1283 len = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 if (copy_to_user(buf, (void*)(tbuf+p), len))
Chuck Lever01b29692007-10-26 13:31:20 -04001285 return -EFAULT;
1286 *ppos += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 return len;
1288}
1289
1290static ssize_t write_flush(struct file * file, const char __user * buf,
1291 size_t count, loff_t *ppos)
1292{
Josef Sipek303b46b2006-12-08 02:37:42 -08001293 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 char tbuf[20];
1295 char *ep;
1296 long flushtime;
1297 if (*ppos || count > sizeof(tbuf)-1)
1298 return -EINVAL;
1299 if (copy_from_user(tbuf, buf, count))
1300 return -EFAULT;
1301 tbuf[count] = 0;
1302 flushtime = simple_strtoul(tbuf, &ep, 0);
1303 if (*ep && *ep != '\n')
1304 return -EINVAL;
1305
1306 cd->flush_time = flushtime;
1307 cd->nextcheck = get_seconds();
1308 cache_flush();
1309
1310 *ppos += count;
1311 return count;
1312}
1313
Arjan van de Venda7071d2007-02-12 00:55:36 -08001314static const struct file_operations cache_flush_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 .open = nonseekable_open,
1316 .read = read_flush,
1317 .write = write_flush,
1318};