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2d6fff63 DH |
1 | /* General filesystem caching interface |
2 | * | |
3 | * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * NOTE!!! See: | |
12 | * | |
13 | * Documentation/filesystems/caching/netfs-api.txt | |
14 | * | |
15 | * for a description of the network filesystem interface declared here. | |
16 | */ | |
17 | ||
18 | #ifndef _LINUX_FSCACHE_H | |
19 | #define _LINUX_FSCACHE_H | |
20 | ||
21 | #include <linux/fs.h> | |
22 | #include <linux/list.h> | |
23 | #include <linux/pagemap.h> | |
24 | #include <linux/pagevec.h> | |
25 | ||
26 | #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE) | |
27 | #define fscache_available() (1) | |
28 | #define fscache_cookie_valid(cookie) (cookie) | |
29 | #else | |
30 | #define fscache_available() (0) | |
31 | #define fscache_cookie_valid(cookie) (0) | |
32 | #endif | |
33 | ||
34 | ||
35 | /* | |
36 | * overload PG_private_2 to give us PG_fscache - this is used to indicate that | |
37 | * a page is currently backed by a local disk cache | |
38 | */ | |
39 | #define PageFsCache(page) PagePrivate2((page)) | |
40 | #define SetPageFsCache(page) SetPagePrivate2((page)) | |
41 | #define ClearPageFsCache(page) ClearPagePrivate2((page)) | |
42 | #define TestSetPageFsCache(page) TestSetPagePrivate2((page)) | |
43 | #define TestClearPageFsCache(page) TestClearPagePrivate2((page)) | |
44 | ||
45 | /* pattern used to fill dead space in an index entry */ | |
46 | #define FSCACHE_INDEX_DEADFILL_PATTERN 0x79 | |
47 | ||
48 | struct pagevec; | |
49 | struct fscache_cache_tag; | |
50 | struct fscache_cookie; | |
51 | struct fscache_netfs; | |
52 | ||
53 | typedef void (*fscache_rw_complete_t)(struct page *page, | |
54 | void *context, | |
55 | int error); | |
56 | ||
57 | /* result of index entry consultation */ | |
58 | enum fscache_checkaux { | |
59 | FSCACHE_CHECKAUX_OKAY, /* entry okay as is */ | |
60 | FSCACHE_CHECKAUX_NEEDS_UPDATE, /* entry requires update */ | |
61 | FSCACHE_CHECKAUX_OBSOLETE, /* entry requires deletion */ | |
62 | }; | |
63 | ||
64 | /* | |
65 | * fscache cookie definition | |
66 | */ | |
67 | struct fscache_cookie_def { | |
68 | /* name of cookie type */ | |
69 | char name[16]; | |
70 | ||
71 | /* cookie type */ | |
72 | uint8_t type; | |
73 | #define FSCACHE_COOKIE_TYPE_INDEX 0 | |
74 | #define FSCACHE_COOKIE_TYPE_DATAFILE 1 | |
75 | ||
76 | /* select the cache into which to insert an entry in this index | |
77 | * - optional | |
78 | * - should return a cache identifier or NULL to cause the cache to be | |
79 | * inherited from the parent if possible or the first cache picked | |
80 | * for a non-index file if not | |
81 | */ | |
82 | struct fscache_cache_tag *(*select_cache)( | |
83 | const void *parent_netfs_data, | |
84 | const void *cookie_netfs_data); | |
85 | ||
86 | /* get an index key | |
87 | * - should store the key data in the buffer | |
ab0cfb92 | 88 | * - should return the amount of data stored |
2d6fff63 DH |
89 | * - not permitted to return an error |
90 | * - the netfs data from the cookie being used as the source is | |
91 | * presented | |
92 | */ | |
93 | uint16_t (*get_key)(const void *cookie_netfs_data, | |
94 | void *buffer, | |
95 | uint16_t bufmax); | |
96 | ||
97 | /* get certain file attributes from the netfs data | |
98 | * - this function can be absent for an index | |
99 | * - not permitted to return an error | |
100 | * - the netfs data from the cookie being used as the source is | |
101 | * presented | |
102 | */ | |
103 | void (*get_attr)(const void *cookie_netfs_data, uint64_t *size); | |
104 | ||
25985edc | 105 | /* get the auxiliary data from netfs data |
2d6fff63 | 106 | * - this function can be absent if the index carries no state data |
25985edc | 107 | * - should store the auxiliary data in the buffer |
2d6fff63 DH |
108 | * - should return the amount of amount stored |
109 | * - not permitted to return an error | |
110 | * - the netfs data from the cookie being used as the source is | |
111 | * presented | |
112 | */ | |
113 | uint16_t (*get_aux)(const void *cookie_netfs_data, | |
114 | void *buffer, | |
115 | uint16_t bufmax); | |
116 | ||
117 | /* consult the netfs about the state of an object | |
118 | * - this function can be absent if the index carries no state data | |
119 | * - the netfs data from the cookie being used as the target is | |
25985edc | 120 | * presented, as is the auxiliary data |
2d6fff63 DH |
121 | */ |
122 | enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, | |
123 | const void *data, | |
124 | uint16_t datalen); | |
125 | ||
126 | /* get an extra reference on a read context | |
127 | * - this function can be absent if the completion function doesn't | |
128 | * require a context | |
129 | */ | |
130 | void (*get_context)(void *cookie_netfs_data, void *context); | |
131 | ||
132 | /* release an extra reference on a read context | |
133 | * - this function can be absent if the completion function doesn't | |
134 | * require a context | |
135 | */ | |
136 | void (*put_context)(void *cookie_netfs_data, void *context); | |
137 | ||
c4d6d8db DH |
138 | /* indicate page that now have cache metadata retained |
139 | * - this function should mark the specified page as now being cached | |
140 | * - the page will have been marked with PG_fscache before this is | |
2d6fff63 DH |
141 | * called, so this is optional |
142 | */ | |
c4d6d8db DH |
143 | void (*mark_page_cached)(void *cookie_netfs_data, |
144 | struct address_space *mapping, | |
145 | struct page *page); | |
2d6fff63 DH |
146 | }; |
147 | ||
148 | /* | |
149 | * fscache cached network filesystem type | |
150 | * - name, version and ops must be filled in before registration | |
151 | * - all other fields will be set during registration | |
152 | */ | |
153 | struct fscache_netfs { | |
154 | uint32_t version; /* indexing version */ | |
155 | const char *name; /* filesystem name */ | |
156 | struct fscache_cookie *primary_index; | |
157 | struct list_head link; /* internal link */ | |
158 | }; | |
159 | ||
94d30ae9 DH |
160 | /* |
161 | * data file or index object cookie | |
162 | * - a file will only appear in one cache | |
163 | * - a request to cache a file may or may not be honoured, subject to | |
164 | * constraints such as disk space | |
165 | * - indices are created on disk just-in-time | |
166 | */ | |
167 | struct fscache_cookie { | |
168 | atomic_t usage; /* number of users of this cookie */ | |
169 | atomic_t n_children; /* number of children of this cookie */ | |
170 | atomic_t n_active; /* number of active users of netfs ptrs */ | |
171 | spinlock_t lock; | |
172 | spinlock_t stores_lock; /* lock on page store tree */ | |
173 | struct hlist_head backing_objects; /* object(s) backing this file/index */ | |
174 | const struct fscache_cookie_def *def; /* definition */ | |
175 | struct fscache_cookie *parent; /* parent of this entry */ | |
176 | void *netfs_data; /* back pointer to netfs */ | |
177 | struct radix_tree_root stores; /* pages to be stored on this cookie */ | |
178 | #define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */ | |
179 | #define FSCACHE_COOKIE_STORING_TAG 1 /* pages tag: writing to cache */ | |
180 | ||
181 | unsigned long flags; | |
182 | #define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */ | |
183 | #define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */ | |
184 | #define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */ | |
185 | #define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */ | |
186 | #define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */ | |
187 | #define FSCACHE_COOKIE_ENABLED 5 /* T if cookie is enabled */ | |
188 | #define FSCACHE_COOKIE_ENABLEMENT_LOCK 6 /* T if cookie is being en/disabled */ | |
189 | }; | |
190 | ||
191 | static inline bool fscache_cookie_enabled(struct fscache_cookie *cookie) | |
192 | { | |
193 | return test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); | |
194 | } | |
195 | ||
2d6fff63 DH |
196 | /* |
197 | * slow-path functions for when there is actually caching available, and the | |
198 | * netfs does actually have a valid token | |
199 | * - these are not to be called directly | |
200 | * - these are undefined symbols when FS-Cache is not configured and the | |
201 | * optimiser takes care of not using them | |
202 | */ | |
726dd7ff DH |
203 | extern int __fscache_register_netfs(struct fscache_netfs *); |
204 | extern void __fscache_unregister_netfs(struct fscache_netfs *); | |
0e04d4ce DH |
205 | extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); |
206 | extern void __fscache_release_cache_tag(struct fscache_cache_tag *); | |
2d6fff63 | 207 | |
ccc4fc3d DH |
208 | extern struct fscache_cookie *__fscache_acquire_cookie( |
209 | struct fscache_cookie *, | |
210 | const struct fscache_cookie_def *, | |
94d30ae9 DH |
211 | void *, bool); |
212 | extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool); | |
da9803bc | 213 | extern int __fscache_check_consistency(struct fscache_cookie *); |
ccc4fc3d | 214 | extern void __fscache_update_cookie(struct fscache_cookie *); |
b5108822 | 215 | extern int __fscache_attr_changed(struct fscache_cookie *); |
ef778e7a DH |
216 | extern void __fscache_invalidate(struct fscache_cookie *); |
217 | extern void __fscache_wait_on_invalidate(struct fscache_cookie *); | |
b5108822 DH |
218 | extern int __fscache_read_or_alloc_page(struct fscache_cookie *, |
219 | struct page *, | |
220 | fscache_rw_complete_t, | |
221 | void *, | |
222 | gfp_t); | |
223 | extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, | |
224 | struct address_space *, | |
225 | struct list_head *, | |
226 | unsigned *, | |
227 | fscache_rw_complete_t, | |
228 | void *, | |
229 | gfp_t); | |
230 | extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); | |
231 | extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t); | |
232 | extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); | |
233 | extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); | |
234 | extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); | |
201a1542 DH |
235 | extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, |
236 | gfp_t); | |
c902ce1b DH |
237 | extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, |
238 | struct inode *); | |
5a6f282a MT |
239 | extern void __fscache_readpages_cancel(struct fscache_cookie *cookie, |
240 | struct list_head *pages); | |
94d30ae9 DH |
241 | extern void __fscache_disable_cookie(struct fscache_cookie *, bool); |
242 | extern void __fscache_enable_cookie(struct fscache_cookie *, | |
243 | bool (*)(void *), void *); | |
ccc4fc3d | 244 | |
2d6fff63 DH |
245 | /** |
246 | * fscache_register_netfs - Register a filesystem as desiring caching services | |
247 | * @netfs: The description of the filesystem | |
248 | * | |
249 | * Register a filesystem as desiring caching services if they're available. | |
250 | * | |
251 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
252 | * description. | |
253 | */ | |
254 | static inline | |
255 | int fscache_register_netfs(struct fscache_netfs *netfs) | |
256 | { | |
726dd7ff DH |
257 | if (fscache_available()) |
258 | return __fscache_register_netfs(netfs); | |
259 | else | |
260 | return 0; | |
2d6fff63 DH |
261 | } |
262 | ||
263 | /** | |
264 | * fscache_unregister_netfs - Indicate that a filesystem no longer desires | |
265 | * caching services | |
266 | * @netfs: The description of the filesystem | |
267 | * | |
268 | * Indicate that a filesystem no longer desires caching services for the | |
269 | * moment. | |
270 | * | |
271 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
272 | * description. | |
273 | */ | |
274 | static inline | |
275 | void fscache_unregister_netfs(struct fscache_netfs *netfs) | |
276 | { | |
726dd7ff DH |
277 | if (fscache_available()) |
278 | __fscache_unregister_netfs(netfs); | |
2d6fff63 DH |
279 | } |
280 | ||
281 | /** | |
282 | * fscache_lookup_cache_tag - Look up a cache tag | |
283 | * @name: The name of the tag to search for | |
284 | * | |
285 | * Acquire a specific cache referral tag that can be used to select a specific | |
286 | * cache in which to cache an index. | |
287 | * | |
288 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
289 | * description. | |
290 | */ | |
291 | static inline | |
292 | struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) | |
293 | { | |
0e04d4ce DH |
294 | if (fscache_available()) |
295 | return __fscache_lookup_cache_tag(name); | |
296 | else | |
297 | return NULL; | |
2d6fff63 DH |
298 | } |
299 | ||
300 | /** | |
301 | * fscache_release_cache_tag - Release a cache tag | |
302 | * @tag: The tag to release | |
303 | * | |
304 | * Release a reference to a cache referral tag previously looked up. | |
305 | * | |
306 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
307 | * description. | |
308 | */ | |
309 | static inline | |
310 | void fscache_release_cache_tag(struct fscache_cache_tag *tag) | |
311 | { | |
0e04d4ce DH |
312 | if (fscache_available()) |
313 | __fscache_release_cache_tag(tag); | |
2d6fff63 DH |
314 | } |
315 | ||
316 | /** | |
317 | * fscache_acquire_cookie - Acquire a cookie to represent a cache object | |
318 | * @parent: The cookie that's to be the parent of this one | |
319 | * @def: A description of the cache object, including callback operations | |
320 | * @netfs_data: An arbitrary piece of data to be kept in the cookie to | |
321 | * represent the cache object to the netfs | |
94d30ae9 | 322 | * @enable: Whether or not to enable a data cookie immediately |
2d6fff63 DH |
323 | * |
324 | * This function is used to inform FS-Cache about part of an index hierarchy | |
325 | * that can be used to locate files. This is done by requesting a cookie for | |
326 | * each index in the path to the file. | |
327 | * | |
328 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
329 | * description. | |
330 | */ | |
331 | static inline | |
332 | struct fscache_cookie *fscache_acquire_cookie( | |
333 | struct fscache_cookie *parent, | |
334 | const struct fscache_cookie_def *def, | |
94d30ae9 DH |
335 | void *netfs_data, |
336 | bool enable) | |
2d6fff63 | 337 | { |
94d30ae9 DH |
338 | if (fscache_cookie_valid(parent) && fscache_cookie_enabled(parent)) |
339 | return __fscache_acquire_cookie(parent, def, netfs_data, | |
340 | enable); | |
ccc4fc3d DH |
341 | else |
342 | return NULL; | |
2d6fff63 DH |
343 | } |
344 | ||
345 | /** | |
346 | * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding | |
347 | * it | |
348 | * @cookie: The cookie being returned | |
349 | * @retire: True if the cache object the cookie represents is to be discarded | |
350 | * | |
351 | * This function returns a cookie to the cache, forcibly discarding the | |
352 | * associated cache object if retire is set to true. | |
353 | * | |
354 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
355 | * description. | |
356 | */ | |
357 | static inline | |
94d30ae9 | 358 | void fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire) |
2d6fff63 | 359 | { |
ccc4fc3d DH |
360 | if (fscache_cookie_valid(cookie)) |
361 | __fscache_relinquish_cookie(cookie, retire); | |
2d6fff63 DH |
362 | } |
363 | ||
da9803bc DH |
364 | /** |
365 | * fscache_check_consistency - Request that if the cache is updated | |
366 | * @cookie: The cookie representing the cache object | |
367 | * | |
368 | * Request an consistency check from fscache, which passes the request | |
369 | * to the backing cache. | |
370 | * | |
371 | * Returns 0 if consistent and -ESTALE if inconsistent. May also | |
372 | * return -ENOMEM and -ERESTARTSYS. | |
373 | */ | |
374 | static inline | |
375 | int fscache_check_consistency(struct fscache_cookie *cookie) | |
376 | { | |
94d30ae9 | 377 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
da9803bc DH |
378 | return __fscache_check_consistency(cookie); |
379 | else | |
380 | return 0; | |
381 | } | |
382 | ||
2d6fff63 DH |
383 | /** |
384 | * fscache_update_cookie - Request that a cache object be updated | |
385 | * @cookie: The cookie representing the cache object | |
386 | * | |
387 | * Request an update of the index data for the cache object associated with the | |
388 | * cookie. | |
389 | * | |
390 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
391 | * description. | |
392 | */ | |
393 | static inline | |
394 | void fscache_update_cookie(struct fscache_cookie *cookie) | |
395 | { | |
94d30ae9 | 396 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ccc4fc3d | 397 | __fscache_update_cookie(cookie); |
2d6fff63 DH |
398 | } |
399 | ||
400 | /** | |
401 | * fscache_pin_cookie - Pin a data-storage cache object in its cache | |
402 | * @cookie: The cookie representing the cache object | |
403 | * | |
404 | * Permit data-storage cache objects to be pinned in the cache. | |
405 | * | |
406 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
407 | * description. | |
408 | */ | |
409 | static inline | |
410 | int fscache_pin_cookie(struct fscache_cookie *cookie) | |
411 | { | |
412 | return -ENOBUFS; | |
413 | } | |
414 | ||
415 | /** | |
416 | * fscache_pin_cookie - Unpin a data-storage cache object in its cache | |
417 | * @cookie: The cookie representing the cache object | |
418 | * | |
419 | * Permit data-storage cache objects to be unpinned from the cache. | |
420 | * | |
421 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
422 | * description. | |
423 | */ | |
424 | static inline | |
425 | void fscache_unpin_cookie(struct fscache_cookie *cookie) | |
426 | { | |
427 | } | |
428 | ||
429 | /** | |
430 | * fscache_attr_changed - Notify cache that an object's attributes changed | |
431 | * @cookie: The cookie representing the cache object | |
432 | * | |
433 | * Send a notification to the cache indicating that an object's attributes have | |
434 | * changed. This includes the data size. These attributes will be obtained | |
435 | * through the get_attr() cookie definition op. | |
436 | * | |
437 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
438 | * description. | |
439 | */ | |
440 | static inline | |
441 | int fscache_attr_changed(struct fscache_cookie *cookie) | |
442 | { | |
94d30ae9 | 443 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
444 | return __fscache_attr_changed(cookie); |
445 | else | |
446 | return -ENOBUFS; | |
2d6fff63 DH |
447 | } |
448 | ||
ef778e7a DH |
449 | /** |
450 | * fscache_invalidate - Notify cache that an object needs invalidation | |
451 | * @cookie: The cookie representing the cache object | |
452 | * | |
453 | * Notify the cache that an object is needs to be invalidated and that it | |
454 | * should abort any retrievals or stores it is doing on the cache. The object | |
455 | * is then marked non-caching until such time as the invalidation is complete. | |
456 | * | |
457 | * This can be called with spinlocks held. | |
458 | * | |
459 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
460 | * description. | |
461 | */ | |
462 | static inline | |
463 | void fscache_invalidate(struct fscache_cookie *cookie) | |
464 | { | |
94d30ae9 | 465 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ef778e7a DH |
466 | __fscache_invalidate(cookie); |
467 | } | |
468 | ||
469 | /** | |
470 | * fscache_wait_on_invalidate - Wait for invalidation to complete | |
471 | * @cookie: The cookie representing the cache object | |
472 | * | |
473 | * Wait for the invalidation of an object to complete. | |
474 | * | |
475 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
476 | * description. | |
477 | */ | |
478 | static inline | |
479 | void fscache_wait_on_invalidate(struct fscache_cookie *cookie) | |
480 | { | |
481 | if (fscache_cookie_valid(cookie)) | |
482 | __fscache_wait_on_invalidate(cookie); | |
483 | } | |
484 | ||
2d6fff63 DH |
485 | /** |
486 | * fscache_reserve_space - Reserve data space for a cached object | |
487 | * @cookie: The cookie representing the cache object | |
488 | * @i_size: The amount of space to be reserved | |
489 | * | |
490 | * Reserve an amount of space in the cache for the cache object attached to a | |
491 | * cookie so that a write to that object within the space can always be | |
492 | * honoured. | |
493 | * | |
494 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
495 | * description. | |
496 | */ | |
497 | static inline | |
498 | int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) | |
499 | { | |
500 | return -ENOBUFS; | |
501 | } | |
502 | ||
503 | /** | |
504 | * fscache_read_or_alloc_page - Read a page from the cache or allocate a block | |
505 | * in which to store it | |
506 | * @cookie: The cookie representing the cache object | |
507 | * @page: The netfs page to fill if possible | |
508 | * @end_io_func: The callback to invoke when and if the page is filled | |
509 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
510 | * @gfp: The conditions under which memory allocation should be made | |
511 | * | |
512 | * Read a page from the cache, or if that's not possible make a potential | |
513 | * one-block reservation in the cache into which the page may be stored once | |
514 | * fetched from the server. | |
515 | * | |
516 | * If the page is not backed by the cache object, or if it there's some reason | |
517 | * it can't be, -ENOBUFS will be returned and nothing more will be done for | |
518 | * that page. | |
519 | * | |
520 | * Else, if that page is backed by the cache, a read will be initiated directly | |
521 | * to the netfs's page and 0 will be returned by this function. The | |
522 | * end_io_func() callback will be invoked when the operation terminates on a | |
523 | * completion or failure. Note that the callback may be invoked before the | |
524 | * return. | |
525 | * | |
526 | * Else, if the page is unbacked, -ENODATA is returned and a block may have | |
527 | * been allocated in the cache. | |
528 | * | |
529 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
530 | * description. | |
531 | */ | |
532 | static inline | |
533 | int fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
534 | struct page *page, | |
535 | fscache_rw_complete_t end_io_func, | |
536 | void *context, | |
537 | gfp_t gfp) | |
538 | { | |
94d30ae9 | 539 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
540 | return __fscache_read_or_alloc_page(cookie, page, end_io_func, |
541 | context, gfp); | |
542 | else | |
543 | return -ENOBUFS; | |
2d6fff63 DH |
544 | } |
545 | ||
546 | /** | |
547 | * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate | |
548 | * blocks in which to store them | |
549 | * @cookie: The cookie representing the cache object | |
550 | * @mapping: The netfs inode mapping to which the pages will be attached | |
551 | * @pages: A list of potential netfs pages to be filled | |
49a3df80 | 552 | * @nr_pages: Number of pages to be read and/or allocated |
2d6fff63 DH |
553 | * @end_io_func: The callback to invoke when and if each page is filled |
554 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
555 | * @gfp: The conditions under which memory allocation should be made | |
556 | * | |
557 | * Read a set of pages from the cache, or if that's not possible, attempt to | |
558 | * make a potential one-block reservation for each page in the cache into which | |
559 | * that page may be stored once fetched from the server. | |
560 | * | |
561 | * If some pages are not backed by the cache object, or if it there's some | |
562 | * reason they can't be, -ENOBUFS will be returned and nothing more will be | |
563 | * done for that pages. | |
564 | * | |
565 | * Else, if some of the pages are backed by the cache, a read will be initiated | |
566 | * directly to the netfs's page and 0 will be returned by this function. The | |
567 | * end_io_func() callback will be invoked when the operation terminates on a | |
568 | * completion or failure. Note that the callback may be invoked before the | |
569 | * return. | |
570 | * | |
571 | * Else, if a page is unbacked, -ENODATA is returned and a block may have | |
572 | * been allocated in the cache. | |
573 | * | |
574 | * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in | |
575 | * regard to different pages, the return values are prioritised in that order. | |
576 | * Any pages submitted for reading are removed from the pages list. | |
577 | * | |
578 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
579 | * description. | |
580 | */ | |
581 | static inline | |
582 | int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
583 | struct address_space *mapping, | |
584 | struct list_head *pages, | |
585 | unsigned *nr_pages, | |
586 | fscache_rw_complete_t end_io_func, | |
587 | void *context, | |
588 | gfp_t gfp) | |
589 | { | |
94d30ae9 | 590 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
591 | return __fscache_read_or_alloc_pages(cookie, mapping, pages, |
592 | nr_pages, end_io_func, | |
593 | context, gfp); | |
594 | else | |
595 | return -ENOBUFS; | |
2d6fff63 DH |
596 | } |
597 | ||
598 | /** | |
599 | * fscache_alloc_page - Allocate a block in which to store a page | |
600 | * @cookie: The cookie representing the cache object | |
601 | * @page: The netfs page to allocate a page for | |
602 | * @gfp: The conditions under which memory allocation should be made | |
603 | * | |
604 | * Request Allocation a block in the cache in which to store a netfs page | |
605 | * without retrieving any contents from the cache. | |
606 | * | |
607 | * If the page is not backed by a file then -ENOBUFS will be returned and | |
608 | * nothing more will be done, and no reservation will be made. | |
609 | * | |
610 | * Else, a block will be allocated if one wasn't already, and 0 will be | |
611 | * returned | |
612 | * | |
613 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
614 | * description. | |
615 | */ | |
616 | static inline | |
617 | int fscache_alloc_page(struct fscache_cookie *cookie, | |
618 | struct page *page, | |
619 | gfp_t gfp) | |
620 | { | |
94d30ae9 | 621 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
622 | return __fscache_alloc_page(cookie, page, gfp); |
623 | else | |
624 | return -ENOBUFS; | |
2d6fff63 DH |
625 | } |
626 | ||
5a6f282a MT |
627 | /** |
628 | * fscache_readpages_cancel - Cancel read/alloc on pages | |
629 | * @cookie: The cookie representing the inode's cache object. | |
630 | * @pages: The netfs pages that we canceled write on in readpages() | |
631 | * | |
632 | * Uncache/unreserve the pages reserved earlier in readpages() via | |
633 | * fscache_readpages_or_alloc() and similar. In most successful caches in | |
634 | * readpages() this doesn't do anything. In cases when the underlying netfs's | |
635 | * readahead failed we need to clean up the pagelist (unmark and uncache). | |
636 | * | |
637 | * This function may sleep as it may have to clean up disk state. | |
638 | */ | |
639 | static inline | |
640 | void fscache_readpages_cancel(struct fscache_cookie *cookie, | |
641 | struct list_head *pages) | |
642 | { | |
643 | if (fscache_cookie_valid(cookie)) | |
644 | __fscache_readpages_cancel(cookie, pages); | |
645 | } | |
646 | ||
2d6fff63 DH |
647 | /** |
648 | * fscache_write_page - Request storage of a page in the cache | |
649 | * @cookie: The cookie representing the cache object | |
650 | * @page: The netfs page to store | |
651 | * @gfp: The conditions under which memory allocation should be made | |
652 | * | |
653 | * Request the contents of the netfs page be written into the cache. This | |
654 | * request may be ignored if no cache block is currently allocated, in which | |
655 | * case it will return -ENOBUFS. | |
656 | * | |
657 | * If a cache block was already allocated, a write will be initiated and 0 will | |
658 | * be returned. The PG_fscache_write page bit is set immediately and will then | |
659 | * be cleared at the completion of the write to indicate the success or failure | |
660 | * of the operation. Note that the completion may happen before the return. | |
661 | * | |
662 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
663 | * description. | |
664 | */ | |
665 | static inline | |
666 | int fscache_write_page(struct fscache_cookie *cookie, | |
667 | struct page *page, | |
668 | gfp_t gfp) | |
669 | { | |
94d30ae9 | 670 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
671 | return __fscache_write_page(cookie, page, gfp); |
672 | else | |
673 | return -ENOBUFS; | |
2d6fff63 DH |
674 | } |
675 | ||
676 | /** | |
677 | * fscache_uncache_page - Indicate that caching is no longer required on a page | |
678 | * @cookie: The cookie representing the cache object | |
679 | * @page: The netfs page that was being cached. | |
680 | * | |
681 | * Tell the cache that we no longer want a page to be cached and that it should | |
682 | * remove any knowledge of the netfs page it may have. | |
683 | * | |
684 | * Note that this cannot cancel any outstanding I/O operations between this | |
685 | * page and the cache. | |
686 | * | |
687 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
688 | * description. | |
689 | */ | |
690 | static inline | |
691 | void fscache_uncache_page(struct fscache_cookie *cookie, | |
692 | struct page *page) | |
693 | { | |
b5108822 DH |
694 | if (fscache_cookie_valid(cookie)) |
695 | __fscache_uncache_page(cookie, page); | |
2d6fff63 DH |
696 | } |
697 | ||
698 | /** | |
699 | * fscache_check_page_write - Ask if a page is being writing to the cache | |
700 | * @cookie: The cookie representing the cache object | |
701 | * @page: The netfs page that is being cached. | |
702 | * | |
703 | * Ask the cache if a page is being written to the cache. | |
704 | * | |
705 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
706 | * description. | |
707 | */ | |
708 | static inline | |
709 | bool fscache_check_page_write(struct fscache_cookie *cookie, | |
710 | struct page *page) | |
711 | { | |
b5108822 DH |
712 | if (fscache_cookie_valid(cookie)) |
713 | return __fscache_check_page_write(cookie, page); | |
2d6fff63 DH |
714 | return false; |
715 | } | |
716 | ||
717 | /** | |
718 | * fscache_wait_on_page_write - Wait for a page to complete writing to the cache | |
719 | * @cookie: The cookie representing the cache object | |
720 | * @page: The netfs page that is being cached. | |
721 | * | |
722 | * Ask the cache to wake us up when a page is no longer being written to the | |
723 | * cache. | |
724 | * | |
725 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
726 | * description. | |
727 | */ | |
728 | static inline | |
729 | void fscache_wait_on_page_write(struct fscache_cookie *cookie, | |
730 | struct page *page) | |
731 | { | |
b5108822 DH |
732 | if (fscache_cookie_valid(cookie)) |
733 | __fscache_wait_on_page_write(cookie, page); | |
2d6fff63 DH |
734 | } |
735 | ||
201a1542 DH |
736 | /** |
737 | * fscache_maybe_release_page - Consider releasing a page, cancelling a store | |
738 | * @cookie: The cookie representing the cache object | |
739 | * @page: The netfs page that is being cached. | |
740 | * @gfp: The gfp flags passed to releasepage() | |
741 | * | |
742 | * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's | |
743 | * releasepage() call. A storage request on the page may cancelled if it is | |
744 | * not currently being processed. | |
745 | * | |
746 | * The function returns true if the page no longer has a storage request on it, | |
747 | * and false if a storage request is left in place. If true is returned, the | |
748 | * page will have been passed to fscache_uncache_page(). If false is returned | |
749 | * the page cannot be freed yet. | |
750 | */ | |
751 | static inline | |
752 | bool fscache_maybe_release_page(struct fscache_cookie *cookie, | |
753 | struct page *page, | |
754 | gfp_t gfp) | |
755 | { | |
756 | if (fscache_cookie_valid(cookie) && PageFsCache(page)) | |
757 | return __fscache_maybe_release_page(cookie, page, gfp); | |
758 | return false; | |
759 | } | |
760 | ||
c902ce1b DH |
761 | /** |
762 | * fscache_uncache_all_inode_pages - Uncache all an inode's pages | |
763 | * @cookie: The cookie representing the inode's cache object. | |
764 | * @inode: The inode to uncache pages from. | |
765 | * | |
766 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them | |
767 | * to be associated with the given cookie. | |
768 | * | |
769 | * This function may sleep. It will wait for pages that are being written out | |
770 | * and will wait whilst the PG_fscache mark is removed by the cache. | |
771 | */ | |
772 | static inline | |
773 | void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, | |
774 | struct inode *inode) | |
775 | { | |
776 | if (fscache_cookie_valid(cookie)) | |
777 | __fscache_uncache_all_inode_pages(cookie, inode); | |
778 | } | |
779 | ||
94d30ae9 DH |
780 | /** |
781 | * fscache_disable_cookie - Disable a cookie | |
782 | * @cookie: The cookie representing the cache object | |
783 | * @invalidate: Invalidate the backing object | |
784 | * | |
785 | * Disable a cookie from accepting further alloc, read, write, invalidate, | |
786 | * update or acquire operations. Outstanding operations can still be waited | |
787 | * upon and pages can still be uncached and the cookie relinquished. | |
788 | * | |
789 | * This will not return until all outstanding operations have completed. | |
790 | * | |
791 | * If @invalidate is set, then the backing object will be invalidated and | |
792 | * detached, otherwise it will just be detached. | |
793 | */ | |
794 | static inline | |
795 | void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate) | |
796 | { | |
797 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) | |
798 | __fscache_disable_cookie(cookie, invalidate); | |
799 | } | |
800 | ||
801 | /** | |
802 | * fscache_enable_cookie - Reenable a cookie | |
803 | * @cookie: The cookie representing the cache object | |
804 | * @can_enable: A function to permit enablement once lock is held | |
805 | * @data: Data for can_enable() | |
806 | * | |
807 | * Reenable a previously disabled cookie, allowing it to accept further alloc, | |
808 | * read, write, invalidate, update or acquire operations. An attempt will be | |
809 | * made to immediately reattach the cookie to a backing object. | |
810 | * | |
811 | * The can_enable() function is called (if not NULL) once the enablement lock | |
812 | * is held to rule on whether enablement is still permitted to go ahead. | |
813 | */ | |
814 | static inline | |
815 | void fscache_enable_cookie(struct fscache_cookie *cookie, | |
816 | bool (*can_enable)(void *data), | |
817 | void *data) | |
818 | { | |
819 | if (fscache_cookie_valid(cookie) && !fscache_cookie_enabled(cookie)) | |
820 | __fscache_enable_cookie(cookie, can_enable, data); | |
821 | } | |
822 | ||
2d6fff63 | 823 | #endif /* _LINUX_FSCACHE_H */ |