blob: ff0c23053d2f04bb40fc8db1dc8c10264bccff79 [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}
Trond Myklebust24c37672008-12-23 16:30:12 -0500101EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
NeilBrown15a5f6b2006-03-27 01:15:02 -0800102
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}
Trond Myklebust24c37672008-12-23 16:30:12 -0500176EXPORT_SYMBOL_GPL(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 Myklebust24c37672008-12-23 16:30:12 -0500248EXPORT_SYMBOL_GPL(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->channel_ent = cd->content_ent = NULL;
317
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700318 p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
319 cd->proc_ent, &cache_flush_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500320 cd->flush_ent = p;
321 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500322 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500323
324 if (cd->cache_request || cd->cache_parse) {
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700325 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
326 cd->proc_ent, &cache_file_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500327 cd->channel_ent = p;
328 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500329 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500330 }
331 if (cd->cache_show) {
Denis V. Luneve7fe2332008-05-02 02:44:36 -0700332 p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
333 cd->proc_ent, &content_file_operations, cd);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500334 cd->content_ent = p;
335 if (p == NULL)
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500336 goto out_nomem;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500337 }
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500338 return 0;
339out_nomem:
340 remove_cache_proc_entries(cd);
341 return -ENOMEM;
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500342}
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500343#else /* CONFIG_PROC_FS */
344static int create_cache_proc_entries(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345{
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500346 return 0;
347}
348#endif
349
350int cache_register(struct cache_detail *cd)
351{
352 int ret;
353
354 ret = create_cache_proc_entries(cd);
355 if (ret)
356 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 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 */
David Howells52bad642006-11-22 14:54:01 +0000369 schedule_delayed_work(&cache_cleaner, 0);
J. Bruce Fieldsdbf847e2007-11-08 17:20:34 -0500370 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371}
Trond Myklebust24c37672008-12-23 16:30:12 -0500372EXPORT_SYMBOL_GPL(cache_register);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500374void cache_unregister(struct cache_detail *cd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375{
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);
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500382 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 }
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);
J. Bruce Fieldsffe93862007-11-12 17:04:29 -0500389 remove_cache_proc_entries(cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 if (list_empty(&cache_list)) {
391 /* module must be being unloaded so its safe to kill the worker */
Trond Myklebust4011cd92007-08-07 15:33:01 -0400392 cancel_delayed_work_sync(&cache_cleaner);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 }
J. Bruce Fieldsdf95a9d2007-11-08 16:09:59 -0500394 return;
395out:
396 printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397}
Trond Myklebust24c37672008-12-23 16:30:12 -0500398EXPORT_SYMBOL_GPL(cache_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
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 */
406static 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 */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800441
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 if (current_detail && current_index < current_detail->hash_size) {
443 struct cache_head *ch, **cp;
444 struct cache_detail *d;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800445
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 write_lock(&current_detail->hash_lock);
447
448 /* Ok, now to clean this strand */
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800449
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 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
NeilBrownbaab9352006-03-27 01:15:09 -0800462 if (atomic_read(&ch->ref.refcount) == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 break;
464 }
465 if (ch) {
466 *cp = ch->next;
467 ch->next = NULL;
468 current_detail->entries--;
469 rv = 1;
470 }
471 write_unlock(&current_detail->hash_lock);
472 d = current_detail;
473 if (!ch)
474 current_index ++;
475 spin_unlock(&cache_list_lock);
476 if (ch)
NeilBrownbaab9352006-03-27 01:15:09 -0800477 cache_put(ch, d);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 } 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 */
David Howells65f27f32006-11-22 14:55:48 +0000487static void do_cache_clean(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488{
489 int delay = 5;
490 if (cache_clean() == -1)
Anton Blanchard6aad89c2009-06-10 12:52:21 -0700491 delay = round_jiffies_relative(30*HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492
493 if (list_empty(&cache_list))
494 delay = 0;
495
496 if (delay)
497 schedule_delayed_work(&cache_cleaner, delay);
498}
499
500
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800501/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 * Clean all caches promptly. This just calls cache_clean
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800503 * repeatedly until we are sure that every cache has had a chance to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 * be fully cleaned
505 */
506void cache_flush(void)
507{
508 while (cache_clean() != -1)
509 cond_resched();
510 while (cache_clean() != -1)
511 cond_resched();
512}
Trond Myklebust24c37672008-12-23 16:30:12 -0500513EXPORT_SYMBOL_GPL(cache_flush);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514
515void 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}
Trond Myklebust24c37672008-12-23 16:30:12 -0500522EXPORT_SYMBOL_GPL(cache_purge);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523
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
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800533 * structure, we allow the request to provide a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 * 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
545static DEFINE_SPINLOCK(cache_defer_lock);
546static LIST_HEAD(cache_defer_list);
547static struct list_head cache_defer_hash[DFR_HASHSIZE];
548static int cache_defer_cnt;
549
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800550static int cache_defer_req(struct cache_req *req, struct cache_head *item)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
552 struct cache_deferred_req *dreq;
553 int hash = DFR_HASH(item);
554
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800555 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 dreq = req->defer(req);
563 if (dreq == NULL)
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800564 return -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 dreq->item = item;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567
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) {
J.Bruce Fields01f3bd12006-12-13 00:35:26 -0800579 dreq = list_entry(cache_defer_list.prev,
580 struct cache_deferred_req, recent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 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 }
NeilBrown4013ede2006-03-27 01:15:07 -0800591 if (!test_bit(CACHE_PENDING, &item->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 /* must have just been validated... */
593 cache_revisit_request(item);
594 }
J.Bruce Fieldse0bb89e2006-12-13 00:35:25 -0800595 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596}
597
598static 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);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800608
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 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
630void 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);
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800638
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 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 *
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500658 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -0800663 * Implemented by linked list of requests. Each open file has
J. Bruce Fieldsa490c682007-11-06 14:15:19 -0500664 * a ->private that also exists in this list. New requests are added
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 * 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
671static DEFINE_SPINLOCK(queue_lock);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800672static DEFINE_MUTEX(queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
674struct cache_queue {
675 struct list_head list;
676 int reader; /* if 0, then request */
677};
678struct cache_request {
679 struct cache_queue q;
680 struct cache_head *item;
681 char * buf;
682 int len;
683 int readers;
684};
685struct cache_reader {
686 struct cache_queue q;
687 int offset; /* if non-0, we have a refcnt on next request */
688};
689
690static ssize_t
691cache_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;
Josef Sipek303b46b2006-12-08 02:37:42 -0800695 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 int err;
697
698 if (count == 0)
699 return 0;
700
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800701 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 * 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);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800714 mutex_unlock(&queue_io_mutex);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800715 BUG_ON(rp->offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 return 0;
717 }
718 rq = container_of(rp->q.list.next, struct cache_request, q.list);
Kris Katterjohn09a62662006-01-08 22:24:28 -0800719 BUG_ON(rq->q.reader);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 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);
NeilBrownbaab9352006-03-27 01:15:09 -0800753 cache_put(rq->item, cd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 kfree(rq->buf);
755 kfree(rq);
756 } else
757 spin_unlock(&queue_lock);
758 }
759 if (err == -EAGAIN)
760 goto again;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800761 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 return err ? err : count;
763}
764
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800765static char write_buf[8192]; /* protected by queue_io_mutex */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766
767static ssize_t
768cache_write(struct file *filp, const char __user *buf, size_t count,
769 loff_t *ppos)
770{
771 int err;
Josef Sipek303b46b2006-12-08 02:37:42 -0800772 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773
774 if (count == 0)
775 return 0;
776 if (count >= sizeof(write_buf))
777 return -EINVAL;
778
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800779 mutex_lock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
781 if (copy_from_user(write_buf, buf, count)) {
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800782 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 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
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800791 mutex_unlock(&queue_io_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 return err ? err : count;
793}
794
795static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
796
797static unsigned int
798cache_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;
Josef Sipek303b46b2006-12-08 02:37:42 -0800803 struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804
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
825static int
826cache_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
855static int
856cache_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
878static int
879cache_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
Arjan van de Venda7071d2007-02-12 00:55:36 -0800911static const struct file_operations cache_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 .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
923static 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)
NeilBrown4013ede2006-03-27 01:15:07 -0800933 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 list_del(&cr->q.list);
935 spin_unlock(&queue_lock);
NeilBrownbaab9352006-03-27 01:15:09 -0800936 cache_put(cr->item, detail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 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
953void 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}
Trond Myklebust24c37672008-12-23 16:30:12 -0500987EXPORT_SYMBOL_GPL(qword_add);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988
989void 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}
Trond Myklebust24c37672008-12-23 16:30:12 -05001016EXPORT_SYMBOL_GPL(qword_addhex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017
1018static 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 */
1031static 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 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001085 * Message is
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 * reply cachename expiry key ... content....
1087 *
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001088 * key and content are both parsed by cache
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 */
1090
1091#define isodigit(c) (isdigit(c) && c <= '7')
1092int 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}
Trond Myklebust24c37672008-12-23 16:30:12 -05001139EXPORT_SYMBOL_GPL(qword_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140
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
1149struct handle {
1150 struct cache_detail *cd;
1151};
1152
1153static void *c_start(struct seq_file *m, loff_t *pos)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001154 __acquires(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155{
1156 loff_t n = *pos;
1157 unsigned hash, entry;
1158 struct cache_head *ch;
1159 struct cache_detail *cd = ((struct handle*)m->private)->cd;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001160
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
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;
YOSHIFUJI Hideakicca51722007-02-09 15:38:13 -08001175 } while(hash < cd->hash_size &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 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
1183static 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
1210static void c_stop(struct seq_file *m, void *p)
Eric Dumazet9a429c42008-01-01 21:58:02 -08001211 __releases(cd->hash_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212{
1213 struct cache_detail *cd = ((struct handle*)m->private)->cd;
1214 read_unlock(&cd->hash_lock);
1215}
1216
1217static 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)
NeilBrown4013ede2006-03-27 01:15:07 -08001226 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
NeilBrownbaab9352006-03-27 01:15:09 -08001227 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 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
Philippe De Muyter56b3d972007-07-10 23:07:31 -07001238static const struct seq_operations cache_content_op = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 .start = c_start,
1240 .next = c_next,
1241 .stop = c_stop,
1242 .show = c_show,
1243};
1244
1245static int content_open(struct inode *inode, struct file *file)
1246{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 struct handle *han;
1248 struct cache_detail *cd = PDE(inode)->data;
1249
Pavel Emelyanovec931032007-10-10 02:31:07 -07001250 han = __seq_open_private(file, &cache_content_op, sizeof(*han));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 if (han == NULL)
1252 return -ENOMEM;
1253
1254 han->cd = cd;
Pavel Emelyanovec931032007-10-10 02:31:07 -07001255 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257
Arjan van de Venda7071d2007-02-12 00:55:36 -08001258static const struct file_operations content_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 .open = content_open,
1260 .read = seq_read,
1261 .llseek = seq_lseek,
Martin Peschke14690fc2007-04-26 01:03:43 -07001262 .release = seq_release_private,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263};
1264
1265static ssize_t read_flush(struct file *file, char __user *buf,
1266 size_t count, loff_t *ppos)
1267{
Josef Sipek303b46b2006-12-08 02:37:42 -08001268 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 char tbuf[20];
1270 unsigned long p = *ppos;
Chuck Lever01b29692007-10-26 13:31:20 -04001271 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272
1273 sprintf(tbuf, "%lu\n", cd->flush_time);
1274 len = strlen(tbuf);
1275 if (p >= len)
1276 return 0;
1277 len -= p;
Chuck Lever01b29692007-10-26 13:31:20 -04001278 if (len > count)
1279 len = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 if (copy_to_user(buf, (void*)(tbuf+p), len))
Chuck Lever01b29692007-10-26 13:31:20 -04001281 return -EFAULT;
1282 *ppos += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 return len;
1284}
1285
1286static ssize_t write_flush(struct file * file, const char __user * buf,
1287 size_t count, loff_t *ppos)
1288{
Josef Sipek303b46b2006-12-08 02:37:42 -08001289 struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 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
Arjan van de Venda7071d2007-02-12 00:55:36 -08001310static const struct file_operations cache_flush_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 .open = nonseekable_open,
1312 .read = read_flush,
1313 .write = write_flush,
1314};