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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 |
88 | * - should return the amount of data stored |
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 | |
105 | /* get the auxiliary data from netfs data |
106 | * - this function can be absent if the index carries no state data |
107 | * - should store the auxiliary data in the buffer |
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 |
120 | * presented, as is the auxiliary data |
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 | |
138 | /* indicate pages that now have cache metadata retained |
139 | * - this function should mark the specified pages as now being cached |
140 | * - the pages will have been marked with PG_fscache before this is |
141 | * called, so this is optional |
142 | */ |
143 | void (*mark_pages_cached)(void *cookie_netfs_data, |
144 | struct address_space *mapping, |
145 | struct pagevec *cached_pvec); |
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 | */ |
176 | extern int __fscache_register_netfs(struct fscache_netfs *); |
177 | extern void __fscache_unregister_netfs(struct fscache_netfs *); |
178 | extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); |
179 | extern void __fscache_release_cache_tag(struct fscache_cache_tag *); |
180 | |
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 *); |
187 | extern int __fscache_attr_changed(struct fscache_cookie *); |
188 | extern int __fscache_read_or_alloc_page(struct fscache_cookie *, |
189 | struct page *, |
190 | fscache_rw_complete_t, |
191 | void *, |
192 | gfp_t); |
193 | extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, |
194 | struct address_space *, |
195 | struct list_head *, |
196 | unsigned *, |
197 | fscache_rw_complete_t, |
198 | void *, |
199 | gfp_t); |
200 | extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); |
201 | extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t); |
202 | extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); |
203 | extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); |
204 | extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); |
205 | extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, |
206 | gfp_t); |
207 | extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, |
208 | struct inode *); |
209 | |
210 | /** |
211 | * fscache_register_netfs - Register a filesystem as desiring caching services |
212 | * @netfs: The description of the filesystem |
213 | * |
214 | * Register a filesystem as desiring caching services if they're available. |
215 | * |
216 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
217 | * description. |
218 | */ |
219 | static inline |
220 | int fscache_register_netfs(struct fscache_netfs *netfs) |
221 | { |
222 | if (fscache_available()) |
223 | return __fscache_register_netfs(netfs); |
224 | else |
225 | return 0; |
226 | } |
227 | |
228 | /** |
229 | * fscache_unregister_netfs - Indicate that a filesystem no longer desires |
230 | * caching services |
231 | * @netfs: The description of the filesystem |
232 | * |
233 | * Indicate that a filesystem no longer desires caching services for the |
234 | * moment. |
235 | * |
236 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
237 | * description. |
238 | */ |
239 | static inline |
240 | void fscache_unregister_netfs(struct fscache_netfs *netfs) |
241 | { |
242 | if (fscache_available()) |
243 | __fscache_unregister_netfs(netfs); |
244 | } |
245 | |
246 | /** |
247 | * fscache_lookup_cache_tag - Look up a cache tag |
248 | * @name: The name of the tag to search for |
249 | * |
250 | * Acquire a specific cache referral tag that can be used to select a specific |
251 | * cache in which to cache an index. |
252 | * |
253 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
254 | * description. |
255 | */ |
256 | static inline |
257 | struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) |
258 | { |
259 | if (fscache_available()) |
260 | return __fscache_lookup_cache_tag(name); |
261 | else |
262 | return NULL; |
263 | } |
264 | |
265 | /** |
266 | * fscache_release_cache_tag - Release a cache tag |
267 | * @tag: The tag to release |
268 | * |
269 | * Release a reference to a cache referral tag previously looked up. |
270 | * |
271 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
272 | * description. |
273 | */ |
274 | static inline |
275 | void fscache_release_cache_tag(struct fscache_cache_tag *tag) |
276 | { |
277 | if (fscache_available()) |
278 | __fscache_release_cache_tag(tag); |
279 | } |
280 | |
281 | /** |
282 | * fscache_acquire_cookie - Acquire a cookie to represent a cache object |
283 | * @parent: The cookie that's to be the parent of this one |
284 | * @def: A description of the cache object, including callback operations |
285 | * @netfs_data: An arbitrary piece of data to be kept in the cookie to |
286 | * represent the cache object to the netfs |
287 | * |
288 | * This function is used to inform FS-Cache about part of an index hierarchy |
289 | * that can be used to locate files. This is done by requesting a cookie for |
290 | * each index in the path to the file. |
291 | * |
292 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
293 | * description. |
294 | */ |
295 | static inline |
296 | struct fscache_cookie *fscache_acquire_cookie( |
297 | struct fscache_cookie *parent, |
298 | const struct fscache_cookie_def *def, |
299 | void *netfs_data) |
300 | { |
301 | if (fscache_cookie_valid(parent)) |
302 | return __fscache_acquire_cookie(parent, def, netfs_data); |
303 | else |
304 | return NULL; |
305 | } |
306 | |
307 | /** |
308 | * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding |
309 | * it |
310 | * @cookie: The cookie being returned |
311 | * @retire: True if the cache object the cookie represents is to be discarded |
312 | * |
313 | * This function returns a cookie to the cache, forcibly discarding the |
314 | * associated cache object if retire is set to true. |
315 | * |
316 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
317 | * description. |
318 | */ |
319 | static inline |
320 | void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) |
321 | { |
322 | if (fscache_cookie_valid(cookie)) |
323 | __fscache_relinquish_cookie(cookie, retire); |
324 | } |
325 | |
326 | /** |
327 | * fscache_update_cookie - Request that a cache object be updated |
328 | * @cookie: The cookie representing the cache object |
329 | * |
330 | * Request an update of the index data for the cache object associated with the |
331 | * cookie. |
332 | * |
333 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
334 | * description. |
335 | */ |
336 | static inline |
337 | void fscache_update_cookie(struct fscache_cookie *cookie) |
338 | { |
339 | if (fscache_cookie_valid(cookie)) |
340 | __fscache_update_cookie(cookie); |
341 | } |
342 | |
343 | /** |
344 | * fscache_pin_cookie - Pin a data-storage cache object in its cache |
345 | * @cookie: The cookie representing the cache object |
346 | * |
347 | * Permit data-storage cache objects to be pinned in the cache. |
348 | * |
349 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
350 | * description. |
351 | */ |
352 | static inline |
353 | int fscache_pin_cookie(struct fscache_cookie *cookie) |
354 | { |
355 | return -ENOBUFS; |
356 | } |
357 | |
358 | /** |
359 | * fscache_pin_cookie - Unpin a data-storage cache object in its cache |
360 | * @cookie: The cookie representing the cache object |
361 | * |
362 | * Permit data-storage cache objects to be unpinned from the cache. |
363 | * |
364 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
365 | * description. |
366 | */ |
367 | static inline |
368 | void fscache_unpin_cookie(struct fscache_cookie *cookie) |
369 | { |
370 | } |
371 | |
372 | /** |
373 | * fscache_attr_changed - Notify cache that an object's attributes changed |
374 | * @cookie: The cookie representing the cache object |
375 | * |
376 | * Send a notification to the cache indicating that an object's attributes have |
377 | * changed. This includes the data size. These attributes will be obtained |
378 | * through the get_attr() cookie definition op. |
379 | * |
380 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
381 | * description. |
382 | */ |
383 | static inline |
384 | int fscache_attr_changed(struct fscache_cookie *cookie) |
385 | { |
386 | if (fscache_cookie_valid(cookie)) |
387 | return __fscache_attr_changed(cookie); |
388 | else |
389 | return -ENOBUFS; |
390 | } |
391 | |
392 | /** |
393 | * fscache_reserve_space - Reserve data space for a cached object |
394 | * @cookie: The cookie representing the cache object |
395 | * @i_size: The amount of space to be reserved |
396 | * |
397 | * Reserve an amount of space in the cache for the cache object attached to a |
398 | * cookie so that a write to that object within the space can always be |
399 | * honoured. |
400 | * |
401 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
402 | * description. |
403 | */ |
404 | static inline |
405 | int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) |
406 | { |
407 | return -ENOBUFS; |
408 | } |
409 | |
410 | /** |
411 | * fscache_read_or_alloc_page - Read a page from the cache or allocate a block |
412 | * in which to store it |
413 | * @cookie: The cookie representing the cache object |
414 | * @page: The netfs page to fill if possible |
415 | * @end_io_func: The callback to invoke when and if the page is filled |
416 | * @context: An arbitrary piece of data to pass on to end_io_func() |
417 | * @gfp: The conditions under which memory allocation should be made |
418 | * |
419 | * Read a page from the cache, or if that's not possible make a potential |
420 | * one-block reservation in the cache into which the page may be stored once |
421 | * fetched from the server. |
422 | * |
423 | * If the page is not backed by the cache object, or if it there's some reason |
424 | * it can't be, -ENOBUFS will be returned and nothing more will be done for |
425 | * that page. |
426 | * |
427 | * Else, if that page is backed by the cache, a read will be initiated directly |
428 | * to the netfs's page and 0 will be returned by this function. The |
429 | * end_io_func() callback will be invoked when the operation terminates on a |
430 | * completion or failure. Note that the callback may be invoked before the |
431 | * return. |
432 | * |
433 | * Else, if the page is unbacked, -ENODATA is returned and a block may have |
434 | * been allocated in the cache. |
435 | * |
436 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
437 | * description. |
438 | */ |
439 | static inline |
440 | int fscache_read_or_alloc_page(struct fscache_cookie *cookie, |
441 | struct page *page, |
442 | fscache_rw_complete_t end_io_func, |
443 | void *context, |
444 | gfp_t gfp) |
445 | { |
446 | if (fscache_cookie_valid(cookie)) |
447 | return __fscache_read_or_alloc_page(cookie, page, end_io_func, |
448 | context, gfp); |
449 | else |
450 | return -ENOBUFS; |
451 | } |
452 | |
453 | /** |
454 | * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate |
455 | * blocks in which to store them |
456 | * @cookie: The cookie representing the cache object |
457 | * @mapping: The netfs inode mapping to which the pages will be attached |
458 | * @pages: A list of potential netfs pages to be filled |
459 | * @nr_pages: Number of pages to be read and/or allocated |
460 | * @end_io_func: The callback to invoke when and if each page is filled |
461 | * @context: An arbitrary piece of data to pass on to end_io_func() |
462 | * @gfp: The conditions under which memory allocation should be made |
463 | * |
464 | * Read a set of pages from the cache, or if that's not possible, attempt to |
465 | * make a potential one-block reservation for each page in the cache into which |
466 | * that page may be stored once fetched from the server. |
467 | * |
468 | * If some pages are not backed by the cache object, or if it there's some |
469 | * reason they can't be, -ENOBUFS will be returned and nothing more will be |
470 | * done for that pages. |
471 | * |
472 | * Else, if some of the pages are backed by the cache, a read will be initiated |
473 | * directly to the netfs's page and 0 will be returned by this function. The |
474 | * end_io_func() callback will be invoked when the operation terminates on a |
475 | * completion or failure. Note that the callback may be invoked before the |
476 | * return. |
477 | * |
478 | * Else, if a page is unbacked, -ENODATA is returned and a block may have |
479 | * been allocated in the cache. |
480 | * |
481 | * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in |
482 | * regard to different pages, the return values are prioritised in that order. |
483 | * Any pages submitted for reading are removed from the pages list. |
484 | * |
485 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
486 | * description. |
487 | */ |
488 | static inline |
489 | int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, |
490 | struct address_space *mapping, |
491 | struct list_head *pages, |
492 | unsigned *nr_pages, |
493 | fscache_rw_complete_t end_io_func, |
494 | void *context, |
495 | gfp_t gfp) |
496 | { |
497 | if (fscache_cookie_valid(cookie)) |
498 | return __fscache_read_or_alloc_pages(cookie, mapping, pages, |
499 | nr_pages, end_io_func, |
500 | context, gfp); |
501 | else |
502 | return -ENOBUFS; |
503 | } |
504 | |
505 | /** |
506 | * fscache_alloc_page - Allocate a block in which to store a page |
507 | * @cookie: The cookie representing the cache object |
508 | * @page: The netfs page to allocate a page for |
509 | * @gfp: The conditions under which memory allocation should be made |
510 | * |
511 | * Request Allocation a block in the cache in which to store a netfs page |
512 | * without retrieving any contents from the cache. |
513 | * |
514 | * If the page is not backed by a file then -ENOBUFS will be returned and |
515 | * nothing more will be done, and no reservation will be made. |
516 | * |
517 | * Else, a block will be allocated if one wasn't already, and 0 will be |
518 | * returned |
519 | * |
520 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
521 | * description. |
522 | */ |
523 | static inline |
524 | int fscache_alloc_page(struct fscache_cookie *cookie, |
525 | struct page *page, |
526 | gfp_t gfp) |
527 | { |
528 | if (fscache_cookie_valid(cookie)) |
529 | return __fscache_alloc_page(cookie, page, gfp); |
530 | else |
531 | return -ENOBUFS; |
532 | } |
533 | |
534 | /** |
535 | * fscache_write_page - Request storage of a page in the cache |
536 | * @cookie: The cookie representing the cache object |
537 | * @page: The netfs page to store |
538 | * @gfp: The conditions under which memory allocation should be made |
539 | * |
540 | * Request the contents of the netfs page be written into the cache. This |
541 | * request may be ignored if no cache block is currently allocated, in which |
542 | * case it will return -ENOBUFS. |
543 | * |
544 | * If a cache block was already allocated, a write will be initiated and 0 will |
545 | * be returned. The PG_fscache_write page bit is set immediately and will then |
546 | * be cleared at the completion of the write to indicate the success or failure |
547 | * of the operation. Note that the completion may happen before the return. |
548 | * |
549 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
550 | * description. |
551 | */ |
552 | static inline |
553 | int fscache_write_page(struct fscache_cookie *cookie, |
554 | struct page *page, |
555 | gfp_t gfp) |
556 | { |
557 | if (fscache_cookie_valid(cookie)) |
558 | return __fscache_write_page(cookie, page, gfp); |
559 | else |
560 | return -ENOBUFS; |
561 | } |
562 | |
563 | /** |
564 | * fscache_uncache_page - Indicate that caching is no longer required on a page |
565 | * @cookie: The cookie representing the cache object |
566 | * @page: The netfs page that was being cached. |
567 | * |
568 | * Tell the cache that we no longer want a page to be cached and that it should |
569 | * remove any knowledge of the netfs page it may have. |
570 | * |
571 | * Note that this cannot cancel any outstanding I/O operations between this |
572 | * page and the cache. |
573 | * |
574 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
575 | * description. |
576 | */ |
577 | static inline |
578 | void fscache_uncache_page(struct fscache_cookie *cookie, |
579 | struct page *page) |
580 | { |
581 | if (fscache_cookie_valid(cookie)) |
582 | __fscache_uncache_page(cookie, page); |
583 | } |
584 | |
585 | /** |
586 | * fscache_check_page_write - Ask if a page is being writing to the cache |
587 | * @cookie: The cookie representing the cache object |
588 | * @page: The netfs page that is being cached. |
589 | * |
590 | * Ask the cache if a page is being written to the cache. |
591 | * |
592 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
593 | * description. |
594 | */ |
595 | static inline |
596 | bool fscache_check_page_write(struct fscache_cookie *cookie, |
597 | struct page *page) |
598 | { |
599 | if (fscache_cookie_valid(cookie)) |
600 | return __fscache_check_page_write(cookie, page); |
601 | return false; |
602 | } |
603 | |
604 | /** |
605 | * fscache_wait_on_page_write - Wait for a page to complete writing to the cache |
606 | * @cookie: The cookie representing the cache object |
607 | * @page: The netfs page that is being cached. |
608 | * |
609 | * Ask the cache to wake us up when a page is no longer being written to the |
610 | * cache. |
611 | * |
612 | * See Documentation/filesystems/caching/netfs-api.txt for a complete |
613 | * description. |
614 | */ |
615 | static inline |
616 | void fscache_wait_on_page_write(struct fscache_cookie *cookie, |
617 | struct page *page) |
618 | { |
619 | if (fscache_cookie_valid(cookie)) |
620 | __fscache_wait_on_page_write(cookie, page); |
621 | } |
622 | |
623 | /** |
624 | * fscache_maybe_release_page - Consider releasing a page, cancelling a store |
625 | * @cookie: The cookie representing the cache object |
626 | * @page: The netfs page that is being cached. |
627 | * @gfp: The gfp flags passed to releasepage() |
628 | * |
629 | * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's |
630 | * releasepage() call. A storage request on the page may cancelled if it is |
631 | * not currently being processed. |
632 | * |
633 | * The function returns true if the page no longer has a storage request on it, |
634 | * and false if a storage request is left in place. If true is returned, the |
635 | * page will have been passed to fscache_uncache_page(). If false is returned |
636 | * the page cannot be freed yet. |
637 | */ |
638 | static inline |
639 | bool fscache_maybe_release_page(struct fscache_cookie *cookie, |
640 | struct page *page, |
641 | gfp_t gfp) |
642 | { |
643 | if (fscache_cookie_valid(cookie) && PageFsCache(page)) |
644 | return __fscache_maybe_release_page(cookie, page, gfp); |
645 | return false; |
646 | } |
647 | |
648 | /** |
649 | * fscache_uncache_all_inode_pages - Uncache all an inode's pages |
650 | * @cookie: The cookie representing the inode's cache object. |
651 | * @inode: The inode to uncache pages from. |
652 | * |
653 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them |
654 | * to be associated with the given cookie. |
655 | * |
656 | * This function may sleep. It will wait for pages that are being written out |
657 | * and will wait whilst the PG_fscache mark is removed by the cache. |
658 | */ |
659 | static inline |
660 | void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, |
661 | struct inode *inode) |
662 | { |
663 | if (fscache_cookie_valid(cookie)) |
664 | __fscache_uncache_all_inode_pages(cookie, inode); |
665 | } |
666 | |
667 | #endif /* _LINUX_FSCACHE_H */ |
668 |
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