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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> | |
ec0328e4 | 25 | #include <linux/list_bl.h> |
2d6fff63 DH |
26 | |
27 | #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE) | |
28 | #define fscache_available() (1) | |
29 | #define fscache_cookie_valid(cookie) (cookie) | |
30 | #else | |
31 | #define fscache_available() (0) | |
32 | #define fscache_cookie_valid(cookie) (0) | |
33 | #endif | |
34 | ||
35 | ||
36 | /* | |
37 | * overload PG_private_2 to give us PG_fscache - this is used to indicate that | |
38 | * a page is currently backed by a local disk cache | |
39 | */ | |
40 | #define PageFsCache(page) PagePrivate2((page)) | |
41 | #define SetPageFsCache(page) SetPagePrivate2((page)) | |
42 | #define ClearPageFsCache(page) ClearPagePrivate2((page)) | |
43 | #define TestSetPageFsCache(page) TestSetPagePrivate2((page)) | |
44 | #define TestClearPageFsCache(page) TestClearPagePrivate2((page)) | |
45 | ||
46 | /* pattern used to fill dead space in an index entry */ | |
47 | #define FSCACHE_INDEX_DEADFILL_PATTERN 0x79 | |
48 | ||
49 | struct pagevec; | |
50 | struct fscache_cache_tag; | |
51 | struct fscache_cookie; | |
52 | struct fscache_netfs; | |
53 | ||
54 | typedef void (*fscache_rw_complete_t)(struct page *page, | |
55 | void *context, | |
56 | int error); | |
57 | ||
58 | /* result of index entry consultation */ | |
59 | enum fscache_checkaux { | |
60 | FSCACHE_CHECKAUX_OKAY, /* entry okay as is */ | |
61 | FSCACHE_CHECKAUX_NEEDS_UPDATE, /* entry requires update */ | |
62 | FSCACHE_CHECKAUX_OBSOLETE, /* entry requires deletion */ | |
63 | }; | |
64 | ||
65 | /* | |
66 | * fscache cookie definition | |
67 | */ | |
68 | struct fscache_cookie_def { | |
69 | /* name of cookie type */ | |
70 | char name[16]; | |
71 | ||
72 | /* cookie type */ | |
73 | uint8_t type; | |
74 | #define FSCACHE_COOKIE_TYPE_INDEX 0 | |
75 | #define FSCACHE_COOKIE_TYPE_DATAFILE 1 | |
76 | ||
77 | /* select the cache into which to insert an entry in this index | |
78 | * - optional | |
79 | * - should return a cache identifier or NULL to cause the cache to be | |
80 | * inherited from the parent if possible or the first cache picked | |
81 | * for a non-index file if not | |
82 | */ | |
83 | struct fscache_cache_tag *(*select_cache)( | |
84 | const void *parent_netfs_data, | |
85 | const void *cookie_netfs_data); | |
86 | ||
2d6fff63 DH |
87 | /* consult the netfs about the state of an object |
88 | * - this function can be absent if the index carries no state data | |
89 | * - the netfs data from the cookie being used as the target is | |
ee1235a9 | 90 | * presented, as is the auxiliary data and the object size |
2d6fff63 DH |
91 | */ |
92 | enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, | |
93 | const void *data, | |
ee1235a9 DH |
94 | uint16_t datalen, |
95 | loff_t object_size); | |
2d6fff63 DH |
96 | |
97 | /* get an extra reference on a read context | |
98 | * - this function can be absent if the completion function doesn't | |
99 | * require a context | |
100 | */ | |
101 | void (*get_context)(void *cookie_netfs_data, void *context); | |
102 | ||
103 | /* release an extra reference on a read context | |
104 | * - this function can be absent if the completion function doesn't | |
105 | * require a context | |
106 | */ | |
107 | void (*put_context)(void *cookie_netfs_data, void *context); | |
108 | ||
c4d6d8db DH |
109 | /* indicate page that now have cache metadata retained |
110 | * - this function should mark the specified page as now being cached | |
111 | * - the page will have been marked with PG_fscache before this is | |
2d6fff63 DH |
112 | * called, so this is optional |
113 | */ | |
c4d6d8db DH |
114 | void (*mark_page_cached)(void *cookie_netfs_data, |
115 | struct address_space *mapping, | |
116 | struct page *page); | |
2d6fff63 DH |
117 | }; |
118 | ||
119 | /* | |
120 | * fscache cached network filesystem type | |
121 | * - name, version and ops must be filled in before registration | |
122 | * - all other fields will be set during registration | |
123 | */ | |
124 | struct fscache_netfs { | |
125 | uint32_t version; /* indexing version */ | |
126 | const char *name; /* filesystem name */ | |
127 | struct fscache_cookie *primary_index; | |
2d6fff63 DH |
128 | }; |
129 | ||
94d30ae9 DH |
130 | /* |
131 | * data file or index object cookie | |
132 | * - a file will only appear in one cache | |
133 | * - a request to cache a file may or may not be honoured, subject to | |
134 | * constraints such as disk space | |
135 | * - indices are created on disk just-in-time | |
136 | */ | |
137 | struct fscache_cookie { | |
138 | atomic_t usage; /* number of users of this cookie */ | |
139 | atomic_t n_children; /* number of children of this cookie */ | |
140 | atomic_t n_active; /* number of active users of netfs ptrs */ | |
141 | spinlock_t lock; | |
142 | spinlock_t stores_lock; /* lock on page store tree */ | |
143 | struct hlist_head backing_objects; /* object(s) backing this file/index */ | |
144 | const struct fscache_cookie_def *def; /* definition */ | |
145 | struct fscache_cookie *parent; /* parent of this entry */ | |
ec0328e4 | 146 | struct hlist_bl_node hash_link; /* Link in hash table */ |
94d30ae9 DH |
147 | void *netfs_data; /* back pointer to netfs */ |
148 | struct radix_tree_root stores; /* pages to be stored on this cookie */ | |
149 | #define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */ | |
150 | #define FSCACHE_COOKIE_STORING_TAG 1 /* pages tag: writing to cache */ | |
151 | ||
152 | unsigned long flags; | |
153 | #define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */ | |
154 | #define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */ | |
155 | #define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */ | |
156 | #define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */ | |
157 | #define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */ | |
158 | #define FSCACHE_COOKIE_ENABLED 5 /* T if cookie is enabled */ | |
159 | #define FSCACHE_COOKIE_ENABLEMENT_LOCK 6 /* T if cookie is being en/disabled */ | |
ec0328e4 DH |
160 | #define FSCACHE_COOKIE_AUX_UPDATED 8 /* T if the auxiliary data was updated */ |
161 | #define FSCACHE_COOKIE_ACQUIRED 9 /* T if cookie is in use */ | |
162 | #define FSCACHE_COOKIE_RELINQUISHING 10 /* T if cookie is being relinquished */ | |
402cb8dd DH |
163 | |
164 | u8 type; /* Type of object */ | |
165 | u8 key_len; /* Length of index key */ | |
166 | u8 aux_len; /* Length of auxiliary data */ | |
ec0328e4 | 167 | u32 key_hash; /* Hash of parent, type, key, len */ |
402cb8dd DH |
168 | union { |
169 | void *key; /* Index key */ | |
170 | u8 inline_key[16]; /* - If the key is short enough */ | |
171 | }; | |
172 | union { | |
173 | void *aux; /* Auxiliary data */ | |
174 | u8 inline_aux[8]; /* - If the aux data is short enough */ | |
175 | }; | |
94d30ae9 DH |
176 | }; |
177 | ||
178 | static inline bool fscache_cookie_enabled(struct fscache_cookie *cookie) | |
179 | { | |
180 | return test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); | |
181 | } | |
182 | ||
2d6fff63 DH |
183 | /* |
184 | * slow-path functions for when there is actually caching available, and the | |
185 | * netfs does actually have a valid token | |
186 | * - these are not to be called directly | |
187 | * - these are undefined symbols when FS-Cache is not configured and the | |
188 | * optimiser takes care of not using them | |
189 | */ | |
726dd7ff DH |
190 | extern int __fscache_register_netfs(struct fscache_netfs *); |
191 | extern void __fscache_unregister_netfs(struct fscache_netfs *); | |
0e04d4ce DH |
192 | extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); |
193 | extern void __fscache_release_cache_tag(struct fscache_cache_tag *); | |
2d6fff63 | 194 | |
ccc4fc3d DH |
195 | extern struct fscache_cookie *__fscache_acquire_cookie( |
196 | struct fscache_cookie *, | |
197 | const struct fscache_cookie_def *, | |
402cb8dd DH |
198 | const void *, size_t, |
199 | const void *, size_t, | |
ee1235a9 | 200 | void *, loff_t, bool); |
402cb8dd DH |
201 | extern void __fscache_relinquish_cookie(struct fscache_cookie *, const void *, bool); |
202 | extern int __fscache_check_consistency(struct fscache_cookie *, const void *); | |
203 | extern void __fscache_update_cookie(struct fscache_cookie *, const void *); | |
b5108822 | 204 | extern int __fscache_attr_changed(struct fscache_cookie *); |
ef778e7a DH |
205 | extern void __fscache_invalidate(struct fscache_cookie *); |
206 | extern void __fscache_wait_on_invalidate(struct fscache_cookie *); | |
b5108822 DH |
207 | extern int __fscache_read_or_alloc_page(struct fscache_cookie *, |
208 | struct page *, | |
209 | fscache_rw_complete_t, | |
210 | void *, | |
211 | gfp_t); | |
212 | extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, | |
213 | struct address_space *, | |
214 | struct list_head *, | |
215 | unsigned *, | |
216 | fscache_rw_complete_t, | |
217 | void *, | |
218 | gfp_t); | |
219 | extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); | |
ee1235a9 | 220 | extern int __fscache_write_page(struct fscache_cookie *, struct page *, loff_t, gfp_t); |
b5108822 DH |
221 | extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); |
222 | extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); | |
223 | extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); | |
201a1542 DH |
224 | extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, |
225 | gfp_t); | |
c902ce1b DH |
226 | extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, |
227 | struct inode *); | |
5a6f282a MT |
228 | extern void __fscache_readpages_cancel(struct fscache_cookie *cookie, |
229 | struct list_head *pages); | |
402cb8dd | 230 | extern void __fscache_disable_cookie(struct fscache_cookie *, const void *, bool); |
ee1235a9 | 231 | extern void __fscache_enable_cookie(struct fscache_cookie *, const void *, loff_t, |
94d30ae9 | 232 | bool (*)(void *), void *); |
ccc4fc3d | 233 | |
2d6fff63 DH |
234 | /** |
235 | * fscache_register_netfs - Register a filesystem as desiring caching services | |
236 | * @netfs: The description of the filesystem | |
237 | * | |
238 | * Register a filesystem as desiring caching services if they're available. | |
239 | * | |
240 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
241 | * description. | |
242 | */ | |
243 | static inline | |
244 | int fscache_register_netfs(struct fscache_netfs *netfs) | |
245 | { | |
726dd7ff DH |
246 | if (fscache_available()) |
247 | return __fscache_register_netfs(netfs); | |
248 | else | |
249 | return 0; | |
2d6fff63 DH |
250 | } |
251 | ||
252 | /** | |
253 | * fscache_unregister_netfs - Indicate that a filesystem no longer desires | |
254 | * caching services | |
255 | * @netfs: The description of the filesystem | |
256 | * | |
257 | * Indicate that a filesystem no longer desires caching services for the | |
258 | * moment. | |
259 | * | |
260 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
261 | * description. | |
262 | */ | |
263 | static inline | |
264 | void fscache_unregister_netfs(struct fscache_netfs *netfs) | |
265 | { | |
726dd7ff DH |
266 | if (fscache_available()) |
267 | __fscache_unregister_netfs(netfs); | |
2d6fff63 DH |
268 | } |
269 | ||
270 | /** | |
271 | * fscache_lookup_cache_tag - Look up a cache tag | |
272 | * @name: The name of the tag to search for | |
273 | * | |
274 | * Acquire a specific cache referral tag that can be used to select a specific | |
275 | * cache in which to cache an index. | |
276 | * | |
277 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
278 | * description. | |
279 | */ | |
280 | static inline | |
281 | struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) | |
282 | { | |
0e04d4ce DH |
283 | if (fscache_available()) |
284 | return __fscache_lookup_cache_tag(name); | |
285 | else | |
286 | return NULL; | |
2d6fff63 DH |
287 | } |
288 | ||
289 | /** | |
290 | * fscache_release_cache_tag - Release a cache tag | |
291 | * @tag: The tag to release | |
292 | * | |
293 | * Release a reference to a cache referral tag previously looked up. | |
294 | * | |
295 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
296 | * description. | |
297 | */ | |
298 | static inline | |
299 | void fscache_release_cache_tag(struct fscache_cache_tag *tag) | |
300 | { | |
0e04d4ce DH |
301 | if (fscache_available()) |
302 | __fscache_release_cache_tag(tag); | |
2d6fff63 DH |
303 | } |
304 | ||
305 | /** | |
306 | * fscache_acquire_cookie - Acquire a cookie to represent a cache object | |
307 | * @parent: The cookie that's to be the parent of this one | |
308 | * @def: A description of the cache object, including callback operations | |
402cb8dd DH |
309 | * @index_key: The index key for this cookie |
310 | * @index_key_len: Size of the index key | |
311 | * @aux_data: The auxiliary data for the cookie (may be NULL) | |
312 | * @aux_data_len: Size of the auxiliary data buffer | |
2d6fff63 DH |
313 | * @netfs_data: An arbitrary piece of data to be kept in the cookie to |
314 | * represent the cache object to the netfs | |
ee1235a9 | 315 | * @object_size: The initial size of object |
94d30ae9 | 316 | * @enable: Whether or not to enable a data cookie immediately |
2d6fff63 DH |
317 | * |
318 | * This function is used to inform FS-Cache about part of an index hierarchy | |
319 | * that can be used to locate files. This is done by requesting a cookie for | |
320 | * each index in the path to the file. | |
321 | * | |
322 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
323 | * description. | |
324 | */ | |
325 | static inline | |
326 | struct fscache_cookie *fscache_acquire_cookie( | |
327 | struct fscache_cookie *parent, | |
328 | const struct fscache_cookie_def *def, | |
402cb8dd DH |
329 | const void *index_key, |
330 | size_t index_key_len, | |
331 | const void *aux_data, | |
332 | size_t aux_data_len, | |
94d30ae9 | 333 | void *netfs_data, |
ee1235a9 | 334 | loff_t object_size, |
94d30ae9 | 335 | bool enable) |
2d6fff63 | 336 | { |
94d30ae9 | 337 | if (fscache_cookie_valid(parent) && fscache_cookie_enabled(parent)) |
402cb8dd DH |
338 | return __fscache_acquire_cookie(parent, def, |
339 | index_key, index_key_len, | |
340 | aux_data, aux_data_len, | |
ee1235a9 | 341 | netfs_data, object_size, enable); |
ccc4fc3d DH |
342 | else |
343 | return NULL; | |
2d6fff63 DH |
344 | } |
345 | ||
346 | /** | |
347 | * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding | |
348 | * it | |
349 | * @cookie: The cookie being returned | |
402cb8dd | 350 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
2d6fff63 DH |
351 | * @retire: True if the cache object the cookie represents is to be discarded |
352 | * | |
353 | * This function returns a cookie to the cache, forcibly discarding the | |
402cb8dd DH |
354 | * associated cache object if retire is set to true. The opportunity is |
355 | * provided to update the auxiliary data in the cache before the object is | |
356 | * disconnected. | |
2d6fff63 DH |
357 | * |
358 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
359 | * description. | |
360 | */ | |
361 | static inline | |
402cb8dd DH |
362 | void fscache_relinquish_cookie(struct fscache_cookie *cookie, |
363 | const void *aux_data, | |
364 | bool retire) | |
2d6fff63 | 365 | { |
ccc4fc3d | 366 | if (fscache_cookie_valid(cookie)) |
402cb8dd | 367 | __fscache_relinquish_cookie(cookie, aux_data, retire); |
2d6fff63 DH |
368 | } |
369 | ||
da9803bc | 370 | /** |
402cb8dd | 371 | * fscache_check_consistency - Request validation of a cache's auxiliary data |
da9803bc | 372 | * @cookie: The cookie representing the cache object |
402cb8dd | 373 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
da9803bc | 374 | * |
402cb8dd DH |
375 | * Request an consistency check from fscache, which passes the request to the |
376 | * backing cache. The auxiliary data on the cookie will be updated first if | |
377 | * @aux_data is set. | |
da9803bc DH |
378 | * |
379 | * Returns 0 if consistent and -ESTALE if inconsistent. May also | |
380 | * return -ENOMEM and -ERESTARTSYS. | |
381 | */ | |
382 | static inline | |
402cb8dd DH |
383 | int fscache_check_consistency(struct fscache_cookie *cookie, |
384 | const void *aux_data) | |
da9803bc | 385 | { |
94d30ae9 | 386 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
402cb8dd | 387 | return __fscache_check_consistency(cookie, aux_data); |
da9803bc DH |
388 | else |
389 | return 0; | |
390 | } | |
391 | ||
2d6fff63 DH |
392 | /** |
393 | * fscache_update_cookie - Request that a cache object be updated | |
394 | * @cookie: The cookie representing the cache object | |
402cb8dd | 395 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
2d6fff63 DH |
396 | * |
397 | * Request an update of the index data for the cache object associated with the | |
402cb8dd DH |
398 | * cookie. The auxiliary data on the cookie will be updated first if @aux_data |
399 | * is set. | |
2d6fff63 DH |
400 | * |
401 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
402 | * description. | |
403 | */ | |
404 | static inline | |
402cb8dd | 405 | void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data) |
2d6fff63 | 406 | { |
94d30ae9 | 407 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
402cb8dd | 408 | __fscache_update_cookie(cookie, aux_data); |
2d6fff63 DH |
409 | } |
410 | ||
411 | /** | |
412 | * fscache_pin_cookie - Pin a data-storage cache object in its cache | |
413 | * @cookie: The cookie representing the cache object | |
414 | * | |
415 | * Permit data-storage cache objects to be pinned in the cache. | |
416 | * | |
417 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
418 | * description. | |
419 | */ | |
420 | static inline | |
421 | int fscache_pin_cookie(struct fscache_cookie *cookie) | |
422 | { | |
423 | return -ENOBUFS; | |
424 | } | |
425 | ||
426 | /** | |
427 | * fscache_pin_cookie - Unpin a data-storage cache object in its cache | |
428 | * @cookie: The cookie representing the cache object | |
429 | * | |
430 | * Permit data-storage cache objects to be unpinned from the cache. | |
431 | * | |
432 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
433 | * description. | |
434 | */ | |
435 | static inline | |
436 | void fscache_unpin_cookie(struct fscache_cookie *cookie) | |
437 | { | |
438 | } | |
439 | ||
440 | /** | |
441 | * fscache_attr_changed - Notify cache that an object's attributes changed | |
442 | * @cookie: The cookie representing the cache object | |
443 | * | |
444 | * Send a notification to the cache indicating that an object's attributes have | |
445 | * changed. This includes the data size. These attributes will be obtained | |
446 | * through the get_attr() cookie definition op. | |
447 | * | |
448 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
449 | * description. | |
450 | */ | |
451 | static inline | |
452 | int fscache_attr_changed(struct fscache_cookie *cookie) | |
453 | { | |
94d30ae9 | 454 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
455 | return __fscache_attr_changed(cookie); |
456 | else | |
457 | return -ENOBUFS; | |
2d6fff63 DH |
458 | } |
459 | ||
ef778e7a DH |
460 | /** |
461 | * fscache_invalidate - Notify cache that an object needs invalidation | |
462 | * @cookie: The cookie representing the cache object | |
463 | * | |
464 | * Notify the cache that an object is needs to be invalidated and that it | |
465 | * should abort any retrievals or stores it is doing on the cache. The object | |
466 | * is then marked non-caching until such time as the invalidation is complete. | |
467 | * | |
468 | * This can be called with spinlocks held. | |
469 | * | |
470 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
471 | * description. | |
472 | */ | |
473 | static inline | |
474 | void fscache_invalidate(struct fscache_cookie *cookie) | |
475 | { | |
94d30ae9 | 476 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ef778e7a DH |
477 | __fscache_invalidate(cookie); |
478 | } | |
479 | ||
480 | /** | |
481 | * fscache_wait_on_invalidate - Wait for invalidation to complete | |
482 | * @cookie: The cookie representing the cache object | |
483 | * | |
484 | * Wait for the invalidation of an object to complete. | |
485 | * | |
486 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
487 | * description. | |
488 | */ | |
489 | static inline | |
490 | void fscache_wait_on_invalidate(struct fscache_cookie *cookie) | |
491 | { | |
492 | if (fscache_cookie_valid(cookie)) | |
493 | __fscache_wait_on_invalidate(cookie); | |
494 | } | |
495 | ||
2d6fff63 DH |
496 | /** |
497 | * fscache_reserve_space - Reserve data space for a cached object | |
498 | * @cookie: The cookie representing the cache object | |
499 | * @i_size: The amount of space to be reserved | |
500 | * | |
501 | * Reserve an amount of space in the cache for the cache object attached to a | |
502 | * cookie so that a write to that object within the space can always be | |
503 | * honoured. | |
504 | * | |
505 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
506 | * description. | |
507 | */ | |
508 | static inline | |
509 | int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) | |
510 | { | |
511 | return -ENOBUFS; | |
512 | } | |
513 | ||
514 | /** | |
515 | * fscache_read_or_alloc_page - Read a page from the cache or allocate a block | |
516 | * in which to store it | |
517 | * @cookie: The cookie representing the cache object | |
518 | * @page: The netfs page to fill if possible | |
519 | * @end_io_func: The callback to invoke when and if the page is filled | |
520 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
521 | * @gfp: The conditions under which memory allocation should be made | |
522 | * | |
523 | * Read a page from the cache, or if that's not possible make a potential | |
524 | * one-block reservation in the cache into which the page may be stored once | |
525 | * fetched from the server. | |
526 | * | |
527 | * If the page is not backed by the cache object, or if it there's some reason | |
528 | * it can't be, -ENOBUFS will be returned and nothing more will be done for | |
529 | * that page. | |
530 | * | |
531 | * Else, if that page is backed by the cache, a read will be initiated directly | |
532 | * to the netfs's page and 0 will be returned by this function. The | |
533 | * end_io_func() callback will be invoked when the operation terminates on a | |
534 | * completion or failure. Note that the callback may be invoked before the | |
535 | * return. | |
536 | * | |
537 | * Else, if the page is unbacked, -ENODATA is returned and a block may have | |
538 | * been allocated in the cache. | |
539 | * | |
540 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
541 | * description. | |
542 | */ | |
543 | static inline | |
544 | int fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
545 | struct page *page, | |
546 | fscache_rw_complete_t end_io_func, | |
547 | void *context, | |
548 | gfp_t gfp) | |
549 | { | |
94d30ae9 | 550 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
551 | return __fscache_read_or_alloc_page(cookie, page, end_io_func, |
552 | context, gfp); | |
553 | else | |
554 | return -ENOBUFS; | |
2d6fff63 DH |
555 | } |
556 | ||
557 | /** | |
558 | * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate | |
559 | * blocks in which to store them | |
560 | * @cookie: The cookie representing the cache object | |
561 | * @mapping: The netfs inode mapping to which the pages will be attached | |
562 | * @pages: A list of potential netfs pages to be filled | |
49a3df80 | 563 | * @nr_pages: Number of pages to be read and/or allocated |
2d6fff63 DH |
564 | * @end_io_func: The callback to invoke when and if each page is filled |
565 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
566 | * @gfp: The conditions under which memory allocation should be made | |
567 | * | |
568 | * Read a set of pages from the cache, or if that's not possible, attempt to | |
569 | * make a potential one-block reservation for each page in the cache into which | |
570 | * that page may be stored once fetched from the server. | |
571 | * | |
572 | * If some pages are not backed by the cache object, or if it there's some | |
573 | * reason they can't be, -ENOBUFS will be returned and nothing more will be | |
574 | * done for that pages. | |
575 | * | |
576 | * Else, if some of the pages are backed by the cache, a read will be initiated | |
577 | * directly to the netfs's page and 0 will be returned by this function. The | |
578 | * end_io_func() callback will be invoked when the operation terminates on a | |
579 | * completion or failure. Note that the callback may be invoked before the | |
580 | * return. | |
581 | * | |
582 | * Else, if a page is unbacked, -ENODATA is returned and a block may have | |
583 | * been allocated in the cache. | |
584 | * | |
585 | * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in | |
586 | * regard to different pages, the return values are prioritised in that order. | |
587 | * Any pages submitted for reading are removed from the pages list. | |
588 | * | |
589 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
590 | * description. | |
591 | */ | |
592 | static inline | |
593 | int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
594 | struct address_space *mapping, | |
595 | struct list_head *pages, | |
596 | unsigned *nr_pages, | |
597 | fscache_rw_complete_t end_io_func, | |
598 | void *context, | |
599 | gfp_t gfp) | |
600 | { | |
94d30ae9 | 601 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
602 | return __fscache_read_or_alloc_pages(cookie, mapping, pages, |
603 | nr_pages, end_io_func, | |
604 | context, gfp); | |
605 | else | |
606 | return -ENOBUFS; | |
2d6fff63 DH |
607 | } |
608 | ||
609 | /** | |
610 | * fscache_alloc_page - Allocate a block in which to store a page | |
611 | * @cookie: The cookie representing the cache object | |
612 | * @page: The netfs page to allocate a page for | |
613 | * @gfp: The conditions under which memory allocation should be made | |
614 | * | |
615 | * Request Allocation a block in the cache in which to store a netfs page | |
616 | * without retrieving any contents from the cache. | |
617 | * | |
618 | * If the page is not backed by a file then -ENOBUFS will be returned and | |
619 | * nothing more will be done, and no reservation will be made. | |
620 | * | |
621 | * Else, a block will be allocated if one wasn't already, and 0 will be | |
622 | * returned | |
623 | * | |
624 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
625 | * description. | |
626 | */ | |
627 | static inline | |
628 | int fscache_alloc_page(struct fscache_cookie *cookie, | |
629 | struct page *page, | |
630 | gfp_t gfp) | |
631 | { | |
94d30ae9 | 632 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
633 | return __fscache_alloc_page(cookie, page, gfp); |
634 | else | |
635 | return -ENOBUFS; | |
2d6fff63 DH |
636 | } |
637 | ||
5a6f282a MT |
638 | /** |
639 | * fscache_readpages_cancel - Cancel read/alloc on pages | |
640 | * @cookie: The cookie representing the inode's cache object. | |
641 | * @pages: The netfs pages that we canceled write on in readpages() | |
642 | * | |
643 | * Uncache/unreserve the pages reserved earlier in readpages() via | |
644 | * fscache_readpages_or_alloc() and similar. In most successful caches in | |
645 | * readpages() this doesn't do anything. In cases when the underlying netfs's | |
646 | * readahead failed we need to clean up the pagelist (unmark and uncache). | |
647 | * | |
648 | * This function may sleep as it may have to clean up disk state. | |
649 | */ | |
650 | static inline | |
651 | void fscache_readpages_cancel(struct fscache_cookie *cookie, | |
652 | struct list_head *pages) | |
653 | { | |
654 | if (fscache_cookie_valid(cookie)) | |
655 | __fscache_readpages_cancel(cookie, pages); | |
656 | } | |
657 | ||
2d6fff63 DH |
658 | /** |
659 | * fscache_write_page - Request storage of a page in the cache | |
660 | * @cookie: The cookie representing the cache object | |
661 | * @page: The netfs page to store | |
ee1235a9 | 662 | * @object_size: Updated size of object |
2d6fff63 DH |
663 | * @gfp: The conditions under which memory allocation should be made |
664 | * | |
665 | * Request the contents of the netfs page be written into the cache. This | |
666 | * request may be ignored if no cache block is currently allocated, in which | |
667 | * case it will return -ENOBUFS. | |
668 | * | |
669 | * If a cache block was already allocated, a write will be initiated and 0 will | |
670 | * be returned. The PG_fscache_write page bit is set immediately and will then | |
671 | * be cleared at the completion of the write to indicate the success or failure | |
672 | * of the operation. Note that the completion may happen before the return. | |
673 | * | |
674 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
675 | * description. | |
676 | */ | |
677 | static inline | |
678 | int fscache_write_page(struct fscache_cookie *cookie, | |
679 | struct page *page, | |
ee1235a9 | 680 | loff_t object_size, |
2d6fff63 DH |
681 | gfp_t gfp) |
682 | { | |
94d30ae9 | 683 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ee1235a9 | 684 | return __fscache_write_page(cookie, page, object_size, gfp); |
b5108822 DH |
685 | else |
686 | return -ENOBUFS; | |
2d6fff63 DH |
687 | } |
688 | ||
689 | /** | |
690 | * fscache_uncache_page - Indicate that caching is no longer required on a page | |
691 | * @cookie: The cookie representing the cache object | |
692 | * @page: The netfs page that was being cached. | |
693 | * | |
694 | * Tell the cache that we no longer want a page to be cached and that it should | |
695 | * remove any knowledge of the netfs page it may have. | |
696 | * | |
697 | * Note that this cannot cancel any outstanding I/O operations between this | |
698 | * page and the cache. | |
699 | * | |
700 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
701 | * description. | |
702 | */ | |
703 | static inline | |
704 | void fscache_uncache_page(struct fscache_cookie *cookie, | |
705 | struct page *page) | |
706 | { | |
b5108822 DH |
707 | if (fscache_cookie_valid(cookie)) |
708 | __fscache_uncache_page(cookie, page); | |
2d6fff63 DH |
709 | } |
710 | ||
711 | /** | |
712 | * fscache_check_page_write - Ask if a page is being writing to the cache | |
713 | * @cookie: The cookie representing the cache object | |
714 | * @page: The netfs page that is being cached. | |
715 | * | |
716 | * Ask the cache if a page is being written to the cache. | |
717 | * | |
718 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
719 | * description. | |
720 | */ | |
721 | static inline | |
722 | bool fscache_check_page_write(struct fscache_cookie *cookie, | |
723 | struct page *page) | |
724 | { | |
b5108822 DH |
725 | if (fscache_cookie_valid(cookie)) |
726 | return __fscache_check_page_write(cookie, page); | |
2d6fff63 DH |
727 | return false; |
728 | } | |
729 | ||
730 | /** | |
731 | * fscache_wait_on_page_write - Wait for a page to complete writing to the cache | |
732 | * @cookie: The cookie representing the cache object | |
733 | * @page: The netfs page that is being cached. | |
734 | * | |
735 | * Ask the cache to wake us up when a page is no longer being written to the | |
736 | * cache. | |
737 | * | |
738 | * See Documentation/filesystems/caching/netfs-api.txt for a complete | |
739 | * description. | |
740 | */ | |
741 | static inline | |
742 | void fscache_wait_on_page_write(struct fscache_cookie *cookie, | |
743 | struct page *page) | |
744 | { | |
b5108822 DH |
745 | if (fscache_cookie_valid(cookie)) |
746 | __fscache_wait_on_page_write(cookie, page); | |
2d6fff63 DH |
747 | } |
748 | ||
201a1542 DH |
749 | /** |
750 | * fscache_maybe_release_page - Consider releasing a page, cancelling a store | |
751 | * @cookie: The cookie representing the cache object | |
752 | * @page: The netfs page that is being cached. | |
753 | * @gfp: The gfp flags passed to releasepage() | |
754 | * | |
755 | * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's | |
756 | * releasepage() call. A storage request on the page may cancelled if it is | |
757 | * not currently being processed. | |
758 | * | |
759 | * The function returns true if the page no longer has a storage request on it, | |
760 | * and false if a storage request is left in place. If true is returned, the | |
761 | * page will have been passed to fscache_uncache_page(). If false is returned | |
762 | * the page cannot be freed yet. | |
763 | */ | |
764 | static inline | |
765 | bool fscache_maybe_release_page(struct fscache_cookie *cookie, | |
766 | struct page *page, | |
767 | gfp_t gfp) | |
768 | { | |
769 | if (fscache_cookie_valid(cookie) && PageFsCache(page)) | |
770 | return __fscache_maybe_release_page(cookie, page, gfp); | |
98801506 | 771 | return true; |
201a1542 DH |
772 | } |
773 | ||
c902ce1b DH |
774 | /** |
775 | * fscache_uncache_all_inode_pages - Uncache all an inode's pages | |
776 | * @cookie: The cookie representing the inode's cache object. | |
777 | * @inode: The inode to uncache pages from. | |
778 | * | |
779 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them | |
780 | * to be associated with the given cookie. | |
781 | * | |
782 | * This function may sleep. It will wait for pages that are being written out | |
783 | * and will wait whilst the PG_fscache mark is removed by the cache. | |
784 | */ | |
785 | static inline | |
786 | void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, | |
787 | struct inode *inode) | |
788 | { | |
789 | if (fscache_cookie_valid(cookie)) | |
790 | __fscache_uncache_all_inode_pages(cookie, inode); | |
791 | } | |
792 | ||
94d30ae9 DH |
793 | /** |
794 | * fscache_disable_cookie - Disable a cookie | |
795 | * @cookie: The cookie representing the cache object | |
402cb8dd | 796 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
94d30ae9 DH |
797 | * @invalidate: Invalidate the backing object |
798 | * | |
799 | * Disable a cookie from accepting further alloc, read, write, invalidate, | |
800 | * update or acquire operations. Outstanding operations can still be waited | |
801 | * upon and pages can still be uncached and the cookie relinquished. | |
802 | * | |
803 | * This will not return until all outstanding operations have completed. | |
804 | * | |
805 | * If @invalidate is set, then the backing object will be invalidated and | |
806 | * detached, otherwise it will just be detached. | |
402cb8dd DH |
807 | * |
808 | * If @aux_data is set, then auxiliary data will be updated from that. | |
94d30ae9 DH |
809 | */ |
810 | static inline | |
402cb8dd DH |
811 | void fscache_disable_cookie(struct fscache_cookie *cookie, |
812 | const void *aux_data, | |
813 | bool invalidate) | |
94d30ae9 DH |
814 | { |
815 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) | |
402cb8dd | 816 | __fscache_disable_cookie(cookie, aux_data, invalidate); |
94d30ae9 DH |
817 | } |
818 | ||
819 | /** | |
820 | * fscache_enable_cookie - Reenable a cookie | |
821 | * @cookie: The cookie representing the cache object | |
402cb8dd | 822 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
ee1235a9 | 823 | * @object_size: Current size of object |
94d30ae9 DH |
824 | * @can_enable: A function to permit enablement once lock is held |
825 | * @data: Data for can_enable() | |
826 | * | |
827 | * Reenable a previously disabled cookie, allowing it to accept further alloc, | |
828 | * read, write, invalidate, update or acquire operations. An attempt will be | |
402cb8dd DH |
829 | * made to immediately reattach the cookie to a backing object. If @aux_data |
830 | * is set, the auxiliary data attached to the cookie will be updated. | |
94d30ae9 DH |
831 | * |
832 | * The can_enable() function is called (if not NULL) once the enablement lock | |
833 | * is held to rule on whether enablement is still permitted to go ahead. | |
834 | */ | |
835 | static inline | |
836 | void fscache_enable_cookie(struct fscache_cookie *cookie, | |
402cb8dd | 837 | const void *aux_data, |
ee1235a9 | 838 | loff_t object_size, |
94d30ae9 DH |
839 | bool (*can_enable)(void *data), |
840 | void *data) | |
841 | { | |
842 | if (fscache_cookie_valid(cookie) && !fscache_cookie_enabled(cookie)) | |
ee1235a9 DH |
843 | __fscache_enable_cookie(cookie, aux_data, object_size, |
844 | can_enable, data); | |
94d30ae9 DH |
845 | } |
846 | ||
2d6fff63 | 847 | #endif /* _LINUX_FSCACHE_H */ |