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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 | /* indicate the cookie is no longer cached | |
148 | * - this function is called when the backing store currently caching | |
149 | * a cookie is removed | |
150 | * - the netfs should use this to clean up any markers indicating | |
151 | * cached pages | |
152 | * - this is mandatory for any object that may have data | |
153 | */ | |
154 | void (*now_uncached)(void *cookie_netfs_data); | |
155 | }; | |
156 | ||
157 | /* | |
158 | * fscache cached network filesystem type | |
159 | * - name, version and ops must be filled in before registration | |
160 | * - all other fields will be set during registration | |
161 | */ | |
162 | struct fscache_netfs { | |
163 | uint32_t version; /* indexing version */ | |
164 | const char *name; /* filesystem name */ | |
165 | struct fscache_cookie *primary_index; | |
166 | struct list_head link; /* internal link */ | |
167 | }; | |
168 | ||
169 | /* | |
170 | * slow-path functions for when there is actually caching available, and the | |
171 | * netfs does actually have a valid token | |
172 | * - these are not to be called directly | |
173 | * - these are undefined symbols when FS-Cache is not configured and the | |
174 | * optimiser takes care of not using them | |
175 | */ | |
726dd7ff DH |
176 | extern int __fscache_register_netfs(struct fscache_netfs *); |
177 | extern void __fscache_unregister_netfs(struct fscache_netfs *); | |
0e04d4ce DH |
178 | extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); |
179 | extern void __fscache_release_cache_tag(struct fscache_cache_tag *); | |
2d6fff63 | 180 | |
ccc4fc3d DH |
181 | extern struct fscache_cookie *__fscache_acquire_cookie( |
182 | struct fscache_cookie *, | |
183 | const struct fscache_cookie_def *, | |
184 | void *); | |
185 | extern void __fscache_relinquish_cookie(struct fscache_cookie *, int); | |
186 | extern void __fscache_update_cookie(struct fscache_cookie *); | |
b5108822 | 187 | extern int __fscache_attr_changed(struct fscache_cookie *); |
ef778e7a DH |
188 | extern void __fscache_invalidate(struct fscache_cookie *); |
189 | extern void __fscache_wait_on_invalidate(struct fscache_cookie *); | |
b5108822 DH |
190 | extern int __fscache_read_or_alloc_page(struct fscache_cookie *, |
191 | struct page *, | |
192 | fscache_rw_complete_t, | |
193 | void *, | |
194 | gfp_t); | |
195 | extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, | |
196 | struct address_space *, | |
197 | struct list_head *, | |
198 | unsigned *, | |
199 | fscache_rw_complete_t, | |
200 | void *, | |
201 | gfp_t); | |
202 | extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); | |
203 | extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t); | |
204 | extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); | |
205 | extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); | |
206 | extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); | |
201a1542 DH |
207 | extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, |
208 | gfp_t); | |
c902ce1b DH |
209 | extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, |
210 | struct inode *); | |
ccc4fc3d | 211 | |
2d6fff63 DH |
212 | /** |
213 | * fscache_register_netfs - Register a filesystem as desiring caching services | |
214 | * @netfs: The description of the filesystem | |
215 | * | |
216 | * Register a filesystem as desiring caching services if they're available. | |
217 | * | |
218 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
219 | * description. | |
220 | */ | |
221 | static inline | |
222 | int fscache_register_netfs(struct fscache_netfs *netfs) | |
223 | { | |
726dd7ff DH |
224 | if (fscache_available()) |
225 | return __fscache_register_netfs(netfs); | |
226 | else | |
227 | return 0; | |
2d6fff63 DH |
228 | } |
229 | ||
230 | /** | |
231 | * fscache_unregister_netfs - Indicate that a filesystem no longer desires | |
232 | * caching services | |
233 | * @netfs: The description of the filesystem | |
234 | * | |
235 | * Indicate that a filesystem no longer desires caching services for the | |
236 | * moment. | |
237 | * | |
238 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
239 | * description. | |
240 | */ | |
241 | static inline | |
242 | void fscache_unregister_netfs(struct fscache_netfs *netfs) | |
243 | { | |
726dd7ff DH |
244 | if (fscache_available()) |
245 | __fscache_unregister_netfs(netfs); | |
2d6fff63 DH |
246 | } |
247 | ||
248 | /** | |
249 | * fscache_lookup_cache_tag - Look up a cache tag | |
250 | * @name: The name of the tag to search for | |
251 | * | |
252 | * Acquire a specific cache referral tag that can be used to select a specific | |
253 | * cache in which to cache an index. | |
254 | * | |
255 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
256 | * description. | |
257 | */ | |
258 | static inline | |
259 | struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) | |
260 | { | |
0e04d4ce DH |
261 | if (fscache_available()) |
262 | return __fscache_lookup_cache_tag(name); | |
263 | else | |
264 | return NULL; | |
2d6fff63 DH |
265 | } |
266 | ||
267 | /** | |
268 | * fscache_release_cache_tag - Release a cache tag | |
269 | * @tag: The tag to release | |
270 | * | |
271 | * Release a reference to a cache referral tag previously looked up. | |
272 | * | |
273 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
274 | * description. | |
275 | */ | |
276 | static inline | |
277 | void fscache_release_cache_tag(struct fscache_cache_tag *tag) | |
278 | { | |
0e04d4ce DH |
279 | if (fscache_available()) |
280 | __fscache_release_cache_tag(tag); | |
2d6fff63 DH |
281 | } |
282 | ||
283 | /** | |
284 | * fscache_acquire_cookie - Acquire a cookie to represent a cache object | |
285 | * @parent: The cookie that's to be the parent of this one | |
286 | * @def: A description of the cache object, including callback operations | |
287 | * @netfs_data: An arbitrary piece of data to be kept in the cookie to | |
288 | * represent the cache object to the netfs | |
289 | * | |
290 | * This function is used to inform FS-Cache about part of an index hierarchy | |
291 | * that can be used to locate files. This is done by requesting a cookie for | |
292 | * each index in the path to the file. | |
293 | * | |
294 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
295 | * description. | |
296 | */ | |
297 | static inline | |
298 | struct fscache_cookie *fscache_acquire_cookie( | |
299 | struct fscache_cookie *parent, | |
300 | const struct fscache_cookie_def *def, | |
301 | void *netfs_data) | |
302 | { | |
ccc4fc3d DH |
303 | if (fscache_cookie_valid(parent)) |
304 | return __fscache_acquire_cookie(parent, def, netfs_data); | |
305 | else | |
306 | return NULL; | |
2d6fff63 DH |
307 | } |
308 | ||
309 | /** | |
310 | * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding | |
311 | * it | |
312 | * @cookie: The cookie being returned | |
313 | * @retire: True if the cache object the cookie represents is to be discarded | |
314 | * | |
315 | * This function returns a cookie to the cache, forcibly discarding the | |
316 | * associated cache object if retire is set to true. | |
317 | * | |
318 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
319 | * description. | |
320 | */ | |
321 | static inline | |
322 | void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) | |
323 | { | |
ccc4fc3d DH |
324 | if (fscache_cookie_valid(cookie)) |
325 | __fscache_relinquish_cookie(cookie, retire); | |
2d6fff63 DH |
326 | } |
327 | ||
328 | /** | |
329 | * fscache_update_cookie - Request that a cache object be updated | |
330 | * @cookie: The cookie representing the cache object | |
331 | * | |
332 | * Request an update of the index data for the cache object associated with the | |
333 | * cookie. | |
334 | * | |
335 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
336 | * description. | |
337 | */ | |
338 | static inline | |
339 | void fscache_update_cookie(struct fscache_cookie *cookie) | |
340 | { | |
ccc4fc3d DH |
341 | if (fscache_cookie_valid(cookie)) |
342 | __fscache_update_cookie(cookie); | |
2d6fff63 DH |
343 | } |
344 | ||
345 | /** | |
346 | * fscache_pin_cookie - Pin a data-storage cache object in its cache | |
347 | * @cookie: The cookie representing the cache object | |
348 | * | |
349 | * Permit data-storage cache objects to be pinned in the cache. | |
350 | * | |
351 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
352 | * description. | |
353 | */ | |
354 | static inline | |
355 | int fscache_pin_cookie(struct fscache_cookie *cookie) | |
356 | { | |
357 | return -ENOBUFS; | |
358 | } | |
359 | ||
360 | /** | |
361 | * fscache_pin_cookie - Unpin a data-storage cache object in its cache | |
362 | * @cookie: The cookie representing the cache object | |
363 | * | |
364 | * Permit data-storage cache objects to be unpinned from the cache. | |
365 | * | |
366 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
367 | * description. | |
368 | */ | |
369 | static inline | |
370 | void fscache_unpin_cookie(struct fscache_cookie *cookie) | |
371 | { | |
372 | } | |
373 | ||
374 | /** | |
375 | * fscache_attr_changed - Notify cache that an object's attributes changed | |
376 | * @cookie: The cookie representing the cache object | |
377 | * | |
378 | * Send a notification to the cache indicating that an object's attributes have | |
379 | * changed. This includes the data size. These attributes will be obtained | |
380 | * through the get_attr() cookie definition op. | |
381 | * | |
382 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
383 | * description. | |
384 | */ | |
385 | static inline | |
386 | int fscache_attr_changed(struct fscache_cookie *cookie) | |
387 | { | |
b5108822 DH |
388 | if (fscache_cookie_valid(cookie)) |
389 | return __fscache_attr_changed(cookie); | |
390 | else | |
391 | return -ENOBUFS; | |
2d6fff63 DH |
392 | } |
393 | ||
ef778e7a DH |
394 | /** |
395 | * fscache_invalidate - Notify cache that an object needs invalidation | |
396 | * @cookie: The cookie representing the cache object | |
397 | * | |
398 | * Notify the cache that an object is needs to be invalidated and that it | |
399 | * should abort any retrievals or stores it is doing on the cache. The object | |
400 | * is then marked non-caching until such time as the invalidation is complete. | |
401 | * | |
402 | * This can be called with spinlocks held. | |
403 | * | |
404 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
405 | * description. | |
406 | */ | |
407 | static inline | |
408 | void fscache_invalidate(struct fscache_cookie *cookie) | |
409 | { | |
410 | if (fscache_cookie_valid(cookie)) | |
411 | __fscache_invalidate(cookie); | |
412 | } | |
413 | ||
414 | /** | |
415 | * fscache_wait_on_invalidate - Wait for invalidation to complete | |
416 | * @cookie: The cookie representing the cache object | |
417 | * | |
418 | * Wait for the invalidation of an object to complete. | |
419 | * | |
420 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
421 | * description. | |
422 | */ | |
423 | static inline | |
424 | void fscache_wait_on_invalidate(struct fscache_cookie *cookie) | |
425 | { | |
426 | if (fscache_cookie_valid(cookie)) | |
427 | __fscache_wait_on_invalidate(cookie); | |
428 | } | |
429 | ||
2d6fff63 DH |
430 | /** |
431 | * fscache_reserve_space - Reserve data space for a cached object | |
432 | * @cookie: The cookie representing the cache object | |
433 | * @i_size: The amount of space to be reserved | |
434 | * | |
435 | * Reserve an amount of space in the cache for the cache object attached to a | |
436 | * cookie so that a write to that object within the space can always be | |
437 | * honoured. | |
438 | * | |
439 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
440 | * description. | |
441 | */ | |
442 | static inline | |
443 | int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) | |
444 | { | |
445 | return -ENOBUFS; | |
446 | } | |
447 | ||
448 | /** | |
449 | * fscache_read_or_alloc_page - Read a page from the cache or allocate a block | |
450 | * in which to store it | |
451 | * @cookie: The cookie representing the cache object | |
452 | * @page: The netfs page to fill if possible | |
453 | * @end_io_func: The callback to invoke when and if the page is filled | |
454 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
455 | * @gfp: The conditions under which memory allocation should be made | |
456 | * | |
457 | * Read a page from the cache, or if that's not possible make a potential | |
458 | * one-block reservation in the cache into which the page may be stored once | |
459 | * fetched from the server. | |
460 | * | |
461 | * If the page is not backed by the cache object, or if it there's some reason | |
462 | * it can't be, -ENOBUFS will be returned and nothing more will be done for | |
463 | * that page. | |
464 | * | |
465 | * Else, if that page is backed by the cache, a read will be initiated directly | |
466 | * to the netfs's page and 0 will be returned by this function. The | |
467 | * end_io_func() callback will be invoked when the operation terminates on a | |
468 | * completion or failure. Note that the callback may be invoked before the | |
469 | * return. | |
470 | * | |
471 | * Else, if the page is unbacked, -ENODATA is returned and a block may have | |
472 | * been allocated in the cache. | |
473 | * | |
474 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
475 | * description. | |
476 | */ | |
477 | static inline | |
478 | int fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
479 | struct page *page, | |
480 | fscache_rw_complete_t end_io_func, | |
481 | void *context, | |
482 | gfp_t gfp) | |
483 | { | |
b5108822 DH |
484 | if (fscache_cookie_valid(cookie)) |
485 | return __fscache_read_or_alloc_page(cookie, page, end_io_func, | |
486 | context, gfp); | |
487 | else | |
488 | return -ENOBUFS; | |
2d6fff63 DH |
489 | } |
490 | ||
491 | /** | |
492 | * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate | |
493 | * blocks in which to store them | |
494 | * @cookie: The cookie representing the cache object | |
495 | * @mapping: The netfs inode mapping to which the pages will be attached | |
496 | * @pages: A list of potential netfs pages to be filled | |
49a3df80 | 497 | * @nr_pages: Number of pages to be read and/or allocated |
2d6fff63 DH |
498 | * @end_io_func: The callback to invoke when and if each page is filled |
499 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
500 | * @gfp: The conditions under which memory allocation should be made | |
501 | * | |
502 | * Read a set of pages from the cache, or if that's not possible, attempt to | |
503 | * make a potential one-block reservation for each page in the cache into which | |
504 | * that page may be stored once fetched from the server. | |
505 | * | |
506 | * If some pages are not backed by the cache object, or if it there's some | |
507 | * reason they can't be, -ENOBUFS will be returned and nothing more will be | |
508 | * done for that pages. | |
509 | * | |
510 | * Else, if some of the pages are backed by the cache, a read will be initiated | |
511 | * directly to the netfs's page and 0 will be returned by this function. The | |
512 | * end_io_func() callback will be invoked when the operation terminates on a | |
513 | * completion or failure. Note that the callback may be invoked before the | |
514 | * return. | |
515 | * | |
516 | * Else, if a page is unbacked, -ENODATA is returned and a block may have | |
517 | * been allocated in the cache. | |
518 | * | |
519 | * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in | |
520 | * regard to different pages, the return values are prioritised in that order. | |
521 | * Any pages submitted for reading are removed from the pages list. | |
522 | * | |
523 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
524 | * description. | |
525 | */ | |
526 | static inline | |
527 | int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
528 | struct address_space *mapping, | |
529 | struct list_head *pages, | |
530 | unsigned *nr_pages, | |
531 | fscache_rw_complete_t end_io_func, | |
532 | void *context, | |
533 | gfp_t gfp) | |
534 | { | |
b5108822 DH |
535 | if (fscache_cookie_valid(cookie)) |
536 | return __fscache_read_or_alloc_pages(cookie, mapping, pages, | |
537 | nr_pages, end_io_func, | |
538 | context, gfp); | |
539 | else | |
540 | return -ENOBUFS; | |
2d6fff63 DH |
541 | } |
542 | ||
543 | /** | |
544 | * fscache_alloc_page - Allocate a block in which to store a page | |
545 | * @cookie: The cookie representing the cache object | |
546 | * @page: The netfs page to allocate a page for | |
547 | * @gfp: The conditions under which memory allocation should be made | |
548 | * | |
549 | * Request Allocation a block in the cache in which to store a netfs page | |
550 | * without retrieving any contents from the cache. | |
551 | * | |
552 | * If the page is not backed by a file then -ENOBUFS will be returned and | |
553 | * nothing more will be done, and no reservation will be made. | |
554 | * | |
555 | * Else, a block will be allocated if one wasn't already, and 0 will be | |
556 | * returned | |
557 | * | |
558 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
559 | * description. | |
560 | */ | |
561 | static inline | |
562 | int fscache_alloc_page(struct fscache_cookie *cookie, | |
563 | struct page *page, | |
564 | gfp_t gfp) | |
565 | { | |
b5108822 DH |
566 | if (fscache_cookie_valid(cookie)) |
567 | return __fscache_alloc_page(cookie, page, gfp); | |
568 | else | |
569 | return -ENOBUFS; | |
2d6fff63 DH |
570 | } |
571 | ||
572 | /** | |
573 | * fscache_write_page - Request storage of a page in the cache | |
574 | * @cookie: The cookie representing the cache object | |
575 | * @page: The netfs page to store | |
576 | * @gfp: The conditions under which memory allocation should be made | |
577 | * | |
578 | * Request the contents of the netfs page be written into the cache. This | |
579 | * request may be ignored if no cache block is currently allocated, in which | |
580 | * case it will return -ENOBUFS. | |
581 | * | |
582 | * If a cache block was already allocated, a write will be initiated and 0 will | |
583 | * be returned. The PG_fscache_write page bit is set immediately and will then | |
584 | * be cleared at the completion of the write to indicate the success or failure | |
585 | * of the operation. Note that the completion may happen before the return. | |
586 | * | |
587 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
588 | * description. | |
589 | */ | |
590 | static inline | |
591 | int fscache_write_page(struct fscache_cookie *cookie, | |
592 | struct page *page, | |
593 | gfp_t gfp) | |
594 | { | |
b5108822 DH |
595 | if (fscache_cookie_valid(cookie)) |
596 | return __fscache_write_page(cookie, page, gfp); | |
597 | else | |
598 | return -ENOBUFS; | |
2d6fff63 DH |
599 | } |
600 | ||
601 | /** | |
602 | * fscache_uncache_page - Indicate that caching is no longer required on a page | |
603 | * @cookie: The cookie representing the cache object | |
604 | * @page: The netfs page that was being cached. | |
605 | * | |
606 | * Tell the cache that we no longer want a page to be cached and that it should | |
607 | * remove any knowledge of the netfs page it may have. | |
608 | * | |
609 | * Note that this cannot cancel any outstanding I/O operations between this | |
610 | * page and the cache. | |
611 | * | |
612 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
613 | * description. | |
614 | */ | |
615 | static inline | |
616 | void fscache_uncache_page(struct fscache_cookie *cookie, | |
617 | struct page *page) | |
618 | { | |
b5108822 DH |
619 | if (fscache_cookie_valid(cookie)) |
620 | __fscache_uncache_page(cookie, page); | |
2d6fff63 DH |
621 | } |
622 | ||
623 | /** | |
624 | * fscache_check_page_write - Ask if a page is being writing to the cache | |
625 | * @cookie: The cookie representing the cache object | |
626 | * @page: The netfs page that is being cached. | |
627 | * | |
628 | * Ask the cache if a page is being written to the cache. | |
629 | * | |
630 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
631 | * description. | |
632 | */ | |
633 | static inline | |
634 | bool fscache_check_page_write(struct fscache_cookie *cookie, | |
635 | struct page *page) | |
636 | { | |
b5108822 DH |
637 | if (fscache_cookie_valid(cookie)) |
638 | return __fscache_check_page_write(cookie, page); | |
2d6fff63 DH |
639 | return false; |
640 | } | |
641 | ||
642 | /** | |
643 | * fscache_wait_on_page_write - Wait for a page to complete writing to the cache | |
644 | * @cookie: The cookie representing the cache object | |
645 | * @page: The netfs page that is being cached. | |
646 | * | |
647 | * Ask the cache to wake us up when a page is no longer being written to the | |
648 | * cache. | |
649 | * | |
650 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
651 | * description. | |
652 | */ | |
653 | static inline | |
654 | void fscache_wait_on_page_write(struct fscache_cookie *cookie, | |
655 | struct page *page) | |
656 | { | |
b5108822 DH |
657 | if (fscache_cookie_valid(cookie)) |
658 | __fscache_wait_on_page_write(cookie, page); | |
2d6fff63 DH |
659 | } |
660 | ||
201a1542 DH |
661 | /** |
662 | * fscache_maybe_release_page - Consider releasing a page, cancelling a store | |
663 | * @cookie: The cookie representing the cache object | |
664 | * @page: The netfs page that is being cached. | |
665 | * @gfp: The gfp flags passed to releasepage() | |
666 | * | |
667 | * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's | |
668 | * releasepage() call. A storage request on the page may cancelled if it is | |
669 | * not currently being processed. | |
670 | * | |
671 | * The function returns true if the page no longer has a storage request on it, | |
672 | * and false if a storage request is left in place. If true is returned, the | |
673 | * page will have been passed to fscache_uncache_page(). If false is returned | |
674 | * the page cannot be freed yet. | |
675 | */ | |
676 | static inline | |
677 | bool fscache_maybe_release_page(struct fscache_cookie *cookie, | |
678 | struct page *page, | |
679 | gfp_t gfp) | |
680 | { | |
681 | if (fscache_cookie_valid(cookie) && PageFsCache(page)) | |
682 | return __fscache_maybe_release_page(cookie, page, gfp); | |
683 | return false; | |
684 | } | |
685 | ||
c902ce1b DH |
686 | /** |
687 | * fscache_uncache_all_inode_pages - Uncache all an inode's pages | |
688 | * @cookie: The cookie representing the inode's cache object. | |
689 | * @inode: The inode to uncache pages from. | |
690 | * | |
691 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them | |
692 | * to be associated with the given cookie. | |
693 | * | |
694 | * This function may sleep. It will wait for pages that are being written out | |
695 | * and will wait whilst the PG_fscache mark is removed by the cache. | |
696 | */ | |
697 | static inline | |
698 | void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, | |
699 | struct inode *inode) | |
700 | { | |
701 | if (fscache_cookie_valid(cookie)) | |
702 | __fscache_uncache_all_inode_pages(cookie, inode); | |
703 | } | |
704 | ||
2d6fff63 | 705 | #endif /* _LINUX_FSCACHE_H */ |