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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2d6fff63 DH |
2 | /* General filesystem caching interface |
3 | * | |
4 | * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
6 | * | |
2d6fff63 DH |
7 | * NOTE!!! See: |
8 | * | |
efc930fa | 9 | * Documentation/filesystems/caching/netfs-api.rst |
2d6fff63 DH |
10 | * |
11 | * for a description of the network filesystem interface declared here. | |
12 | */ | |
13 | ||
14 | #ifndef _LINUX_FSCACHE_H | |
15 | #define _LINUX_FSCACHE_H | |
16 | ||
17 | #include <linux/fs.h> | |
18 | #include <linux/list.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/pagevec.h> | |
ec0328e4 | 21 | #include <linux/list_bl.h> |
b533a83f | 22 | #include <linux/netfs.h> |
2d6fff63 DH |
23 | |
24 | #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE) | |
25 | #define fscache_available() (1) | |
26 | #define fscache_cookie_valid(cookie) (cookie) | |
27 | #else | |
28 | #define fscache_available() (0) | |
29 | #define fscache_cookie_valid(cookie) (0) | |
30 | #endif | |
31 | ||
32 | ||
2d6fff63 DH |
33 | /* pattern used to fill dead space in an index entry */ |
34 | #define FSCACHE_INDEX_DEADFILL_PATTERN 0x79 | |
35 | ||
36 | struct pagevec; | |
37 | struct fscache_cache_tag; | |
38 | struct fscache_cookie; | |
39 | struct fscache_netfs; | |
26aaeffc | 40 | struct netfs_read_request; |
2d6fff63 DH |
41 | |
42 | typedef void (*fscache_rw_complete_t)(struct page *page, | |
43 | void *context, | |
44 | int error); | |
45 | ||
46 | /* result of index entry consultation */ | |
47 | enum fscache_checkaux { | |
48 | FSCACHE_CHECKAUX_OKAY, /* entry okay as is */ | |
49 | FSCACHE_CHECKAUX_NEEDS_UPDATE, /* entry requires update */ | |
50 | FSCACHE_CHECKAUX_OBSOLETE, /* entry requires deletion */ | |
51 | }; | |
52 | ||
53 | /* | |
54 | * fscache cookie definition | |
55 | */ | |
56 | struct fscache_cookie_def { | |
57 | /* name of cookie type */ | |
58 | char name[16]; | |
59 | ||
60 | /* cookie type */ | |
61 | uint8_t type; | |
62 | #define FSCACHE_COOKIE_TYPE_INDEX 0 | |
63 | #define FSCACHE_COOKIE_TYPE_DATAFILE 1 | |
64 | ||
65 | /* select the cache into which to insert an entry in this index | |
66 | * - optional | |
67 | * - should return a cache identifier or NULL to cause the cache to be | |
68 | * inherited from the parent if possible or the first cache picked | |
69 | * for a non-index file if not | |
70 | */ | |
71 | struct fscache_cache_tag *(*select_cache)( | |
72 | const void *parent_netfs_data, | |
73 | const void *cookie_netfs_data); | |
74 | ||
2d6fff63 DH |
75 | /* consult the netfs about the state of an object |
76 | * - this function can be absent if the index carries no state data | |
77 | * - the netfs data from the cookie being used as the target is | |
ee1235a9 | 78 | * presented, as is the auxiliary data and the object size |
2d6fff63 DH |
79 | */ |
80 | enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, | |
81 | const void *data, | |
ee1235a9 DH |
82 | uint16_t datalen, |
83 | loff_t object_size); | |
2d6fff63 DH |
84 | |
85 | /* get an extra reference on a read context | |
86 | * - this function can be absent if the completion function doesn't | |
87 | * require a context | |
88 | */ | |
89 | void (*get_context)(void *cookie_netfs_data, void *context); | |
90 | ||
91 | /* release an extra reference on a read context | |
92 | * - this function can be absent if the completion function doesn't | |
93 | * require a context | |
94 | */ | |
95 | void (*put_context)(void *cookie_netfs_data, void *context); | |
96 | ||
c4d6d8db DH |
97 | /* indicate page that now have cache metadata retained |
98 | * - this function should mark the specified page as now being cached | |
99 | * - the page will have been marked with PG_fscache before this is | |
2d6fff63 DH |
100 | * called, so this is optional |
101 | */ | |
c4d6d8db DH |
102 | void (*mark_page_cached)(void *cookie_netfs_data, |
103 | struct address_space *mapping, | |
104 | struct page *page); | |
2d6fff63 DH |
105 | }; |
106 | ||
107 | /* | |
108 | * fscache cached network filesystem type | |
109 | * - name, version and ops must be filled in before registration | |
110 | * - all other fields will be set during registration | |
111 | */ | |
112 | struct fscache_netfs { | |
113 | uint32_t version; /* indexing version */ | |
114 | const char *name; /* filesystem name */ | |
115 | struct fscache_cookie *primary_index; | |
2d6fff63 DH |
116 | }; |
117 | ||
94d30ae9 DH |
118 | /* |
119 | * data file or index object cookie | |
120 | * - a file will only appear in one cache | |
121 | * - a request to cache a file may or may not be honoured, subject to | |
122 | * constraints such as disk space | |
123 | * - indices are created on disk just-in-time | |
124 | */ | |
125 | struct fscache_cookie { | |
126 | atomic_t usage; /* number of users of this cookie */ | |
127 | atomic_t n_children; /* number of children of this cookie */ | |
128 | atomic_t n_active; /* number of active users of netfs ptrs */ | |
129 | spinlock_t lock; | |
130 | spinlock_t stores_lock; /* lock on page store tree */ | |
131 | struct hlist_head backing_objects; /* object(s) backing this file/index */ | |
132 | const struct fscache_cookie_def *def; /* definition */ | |
133 | struct fscache_cookie *parent; /* parent of this entry */ | |
ec0328e4 | 134 | struct hlist_bl_node hash_link; /* Link in hash table */ |
94d30ae9 DH |
135 | void *netfs_data; /* back pointer to netfs */ |
136 | struct radix_tree_root stores; /* pages to be stored on this cookie */ | |
137 | #define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */ | |
138 | #define FSCACHE_COOKIE_STORING_TAG 1 /* pages tag: writing to cache */ | |
139 | ||
140 | unsigned long flags; | |
141 | #define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */ | |
142 | #define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */ | |
143 | #define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */ | |
144 | #define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */ | |
145 | #define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */ | |
146 | #define FSCACHE_COOKIE_ENABLED 5 /* T if cookie is enabled */ | |
147 | #define FSCACHE_COOKIE_ENABLEMENT_LOCK 6 /* T if cookie is being en/disabled */ | |
ec0328e4 DH |
148 | #define FSCACHE_COOKIE_AUX_UPDATED 8 /* T if the auxiliary data was updated */ |
149 | #define FSCACHE_COOKIE_ACQUIRED 9 /* T if cookie is in use */ | |
150 | #define FSCACHE_COOKIE_RELINQUISHING 10 /* T if cookie is being relinquished */ | |
402cb8dd DH |
151 | |
152 | u8 type; /* Type of object */ | |
153 | u8 key_len; /* Length of index key */ | |
154 | u8 aux_len; /* Length of auxiliary data */ | |
ec0328e4 | 155 | u32 key_hash; /* Hash of parent, type, key, len */ |
402cb8dd DH |
156 | union { |
157 | void *key; /* Index key */ | |
158 | u8 inline_key[16]; /* - If the key is short enough */ | |
159 | }; | |
160 | union { | |
161 | void *aux; /* Auxiliary data */ | |
162 | u8 inline_aux[8]; /* - If the aux data is short enough */ | |
163 | }; | |
94d30ae9 DH |
164 | }; |
165 | ||
166 | static inline bool fscache_cookie_enabled(struct fscache_cookie *cookie) | |
167 | { | |
168 | return test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); | |
169 | } | |
170 | ||
2d6fff63 DH |
171 | /* |
172 | * slow-path functions for when there is actually caching available, and the | |
173 | * netfs does actually have a valid token | |
174 | * - these are not to be called directly | |
175 | * - these are undefined symbols when FS-Cache is not configured and the | |
176 | * optimiser takes care of not using them | |
177 | */ | |
726dd7ff DH |
178 | extern int __fscache_register_netfs(struct fscache_netfs *); |
179 | extern void __fscache_unregister_netfs(struct fscache_netfs *); | |
0e04d4ce DH |
180 | extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); |
181 | extern void __fscache_release_cache_tag(struct fscache_cache_tag *); | |
2d6fff63 | 182 | |
ccc4fc3d DH |
183 | extern struct fscache_cookie *__fscache_acquire_cookie( |
184 | struct fscache_cookie *, | |
185 | const struct fscache_cookie_def *, | |
402cb8dd DH |
186 | const void *, size_t, |
187 | const void *, size_t, | |
ee1235a9 | 188 | void *, loff_t, bool); |
402cb8dd DH |
189 | extern void __fscache_relinquish_cookie(struct fscache_cookie *, const void *, bool); |
190 | extern int __fscache_check_consistency(struct fscache_cookie *, const void *); | |
191 | extern void __fscache_update_cookie(struct fscache_cookie *, const void *); | |
b5108822 | 192 | extern int __fscache_attr_changed(struct fscache_cookie *); |
ef778e7a DH |
193 | extern void __fscache_invalidate(struct fscache_cookie *); |
194 | extern void __fscache_wait_on_invalidate(struct fscache_cookie *); | |
26aaeffc DH |
195 | |
196 | #ifdef FSCACHE_USE_NEW_IO_API | |
197 | extern int __fscache_begin_read_operation(struct netfs_read_request *, struct fscache_cookie *); | |
198 | #else | |
b5108822 DH |
199 | extern int __fscache_read_or_alloc_page(struct fscache_cookie *, |
200 | struct page *, | |
201 | fscache_rw_complete_t, | |
202 | void *, | |
203 | gfp_t); | |
204 | extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, | |
205 | struct address_space *, | |
206 | struct list_head *, | |
207 | unsigned *, | |
208 | fscache_rw_complete_t, | |
209 | void *, | |
210 | gfp_t); | |
211 | extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); | |
ee1235a9 | 212 | extern int __fscache_write_page(struct fscache_cookie *, struct page *, loff_t, gfp_t); |
b5108822 DH |
213 | extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); |
214 | extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); | |
215 | extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); | |
201a1542 DH |
216 | extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, |
217 | gfp_t); | |
c902ce1b DH |
218 | extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, |
219 | struct inode *); | |
5a6f282a MT |
220 | extern void __fscache_readpages_cancel(struct fscache_cookie *cookie, |
221 | struct list_head *pages); | |
26aaeffc DH |
222 | #endif /* FSCACHE_USE_NEW_IO_API */ |
223 | ||
402cb8dd | 224 | extern void __fscache_disable_cookie(struct fscache_cookie *, const void *, bool); |
ee1235a9 | 225 | extern void __fscache_enable_cookie(struct fscache_cookie *, const void *, loff_t, |
94d30ae9 | 226 | bool (*)(void *), void *); |
ccc4fc3d | 227 | |
2d6fff63 DH |
228 | /** |
229 | * fscache_register_netfs - Register a filesystem as desiring caching services | |
230 | * @netfs: The description of the filesystem | |
231 | * | |
232 | * Register a filesystem as desiring caching services if they're available. | |
233 | * | |
efc930fa | 234 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
235 | * description. |
236 | */ | |
237 | static inline | |
238 | int fscache_register_netfs(struct fscache_netfs *netfs) | |
239 | { | |
726dd7ff DH |
240 | if (fscache_available()) |
241 | return __fscache_register_netfs(netfs); | |
242 | else | |
243 | return 0; | |
2d6fff63 DH |
244 | } |
245 | ||
246 | /** | |
247 | * fscache_unregister_netfs - Indicate that a filesystem no longer desires | |
248 | * caching services | |
249 | * @netfs: The description of the filesystem | |
250 | * | |
251 | * Indicate that a filesystem no longer desires caching services for the | |
252 | * moment. | |
253 | * | |
efc930fa | 254 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
255 | * description. |
256 | */ | |
257 | static inline | |
258 | void fscache_unregister_netfs(struct fscache_netfs *netfs) | |
259 | { | |
726dd7ff DH |
260 | if (fscache_available()) |
261 | __fscache_unregister_netfs(netfs); | |
2d6fff63 DH |
262 | } |
263 | ||
264 | /** | |
265 | * fscache_lookup_cache_tag - Look up a cache tag | |
266 | * @name: The name of the tag to search for | |
267 | * | |
268 | * Acquire a specific cache referral tag that can be used to select a specific | |
269 | * cache in which to cache an index. | |
270 | * | |
efc930fa | 271 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
272 | * description. |
273 | */ | |
274 | static inline | |
275 | struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) | |
276 | { | |
0e04d4ce DH |
277 | if (fscache_available()) |
278 | return __fscache_lookup_cache_tag(name); | |
279 | else | |
280 | return NULL; | |
2d6fff63 DH |
281 | } |
282 | ||
283 | /** | |
284 | * fscache_release_cache_tag - Release a cache tag | |
285 | * @tag: The tag to release | |
286 | * | |
287 | * Release a reference to a cache referral tag previously looked up. | |
288 | * | |
efc930fa | 289 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
290 | * description. |
291 | */ | |
292 | static inline | |
293 | void fscache_release_cache_tag(struct fscache_cache_tag *tag) | |
294 | { | |
0e04d4ce DH |
295 | if (fscache_available()) |
296 | __fscache_release_cache_tag(tag); | |
2d6fff63 DH |
297 | } |
298 | ||
299 | /** | |
300 | * fscache_acquire_cookie - Acquire a cookie to represent a cache object | |
301 | * @parent: The cookie that's to be the parent of this one | |
302 | * @def: A description of the cache object, including callback operations | |
402cb8dd DH |
303 | * @index_key: The index key for this cookie |
304 | * @index_key_len: Size of the index key | |
305 | * @aux_data: The auxiliary data for the cookie (may be NULL) | |
306 | * @aux_data_len: Size of the auxiliary data buffer | |
2d6fff63 DH |
307 | * @netfs_data: An arbitrary piece of data to be kept in the cookie to |
308 | * represent the cache object to the netfs | |
ee1235a9 | 309 | * @object_size: The initial size of object |
94d30ae9 | 310 | * @enable: Whether or not to enable a data cookie immediately |
2d6fff63 DH |
311 | * |
312 | * This function is used to inform FS-Cache about part of an index hierarchy | |
313 | * that can be used to locate files. This is done by requesting a cookie for | |
314 | * each index in the path to the file. | |
315 | * | |
efc930fa | 316 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
317 | * description. |
318 | */ | |
319 | static inline | |
320 | struct fscache_cookie *fscache_acquire_cookie( | |
321 | struct fscache_cookie *parent, | |
322 | const struct fscache_cookie_def *def, | |
402cb8dd DH |
323 | const void *index_key, |
324 | size_t index_key_len, | |
325 | const void *aux_data, | |
326 | size_t aux_data_len, | |
94d30ae9 | 327 | void *netfs_data, |
ee1235a9 | 328 | loff_t object_size, |
94d30ae9 | 329 | bool enable) |
2d6fff63 | 330 | { |
94d30ae9 | 331 | if (fscache_cookie_valid(parent) && fscache_cookie_enabled(parent)) |
402cb8dd DH |
332 | return __fscache_acquire_cookie(parent, def, |
333 | index_key, index_key_len, | |
334 | aux_data, aux_data_len, | |
ee1235a9 | 335 | netfs_data, object_size, enable); |
ccc4fc3d DH |
336 | else |
337 | return NULL; | |
2d6fff63 DH |
338 | } |
339 | ||
340 | /** | |
341 | * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding | |
342 | * it | |
343 | * @cookie: The cookie being returned | |
402cb8dd | 344 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
2d6fff63 DH |
345 | * @retire: True if the cache object the cookie represents is to be discarded |
346 | * | |
347 | * This function returns a cookie to the cache, forcibly discarding the | |
402cb8dd DH |
348 | * associated cache object if retire is set to true. The opportunity is |
349 | * provided to update the auxiliary data in the cache before the object is | |
350 | * disconnected. | |
2d6fff63 | 351 | * |
efc930fa | 352 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
353 | * description. |
354 | */ | |
355 | static inline | |
402cb8dd DH |
356 | void fscache_relinquish_cookie(struct fscache_cookie *cookie, |
357 | const void *aux_data, | |
358 | bool retire) | |
2d6fff63 | 359 | { |
ccc4fc3d | 360 | if (fscache_cookie_valid(cookie)) |
402cb8dd | 361 | __fscache_relinquish_cookie(cookie, aux_data, retire); |
2d6fff63 DH |
362 | } |
363 | ||
da9803bc | 364 | /** |
402cb8dd | 365 | * fscache_check_consistency - Request validation of a cache's auxiliary data |
da9803bc | 366 | * @cookie: The cookie representing the cache object |
402cb8dd | 367 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
da9803bc | 368 | * |
402cb8dd DH |
369 | * Request an consistency check from fscache, which passes the request to the |
370 | * backing cache. The auxiliary data on the cookie will be updated first if | |
371 | * @aux_data is set. | |
da9803bc DH |
372 | * |
373 | * Returns 0 if consistent and -ESTALE if inconsistent. May also | |
374 | * return -ENOMEM and -ERESTARTSYS. | |
375 | */ | |
376 | static inline | |
402cb8dd DH |
377 | int fscache_check_consistency(struct fscache_cookie *cookie, |
378 | const void *aux_data) | |
da9803bc | 379 | { |
94d30ae9 | 380 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
402cb8dd | 381 | return __fscache_check_consistency(cookie, aux_data); |
da9803bc DH |
382 | else |
383 | return 0; | |
384 | } | |
385 | ||
2d6fff63 DH |
386 | /** |
387 | * fscache_update_cookie - Request that a cache object be updated | |
388 | * @cookie: The cookie representing the cache object | |
402cb8dd | 389 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
2d6fff63 DH |
390 | * |
391 | * Request an update of the index data for the cache object associated with the | |
402cb8dd DH |
392 | * cookie. The auxiliary data on the cookie will be updated first if @aux_data |
393 | * is set. | |
2d6fff63 | 394 | * |
efc930fa | 395 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
396 | * description. |
397 | */ | |
398 | static inline | |
402cb8dd | 399 | void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data) |
2d6fff63 | 400 | { |
94d30ae9 | 401 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
402cb8dd | 402 | __fscache_update_cookie(cookie, aux_data); |
2d6fff63 DH |
403 | } |
404 | ||
405 | /** | |
406 | * fscache_pin_cookie - Pin a data-storage cache object in its cache | |
407 | * @cookie: The cookie representing the cache object | |
408 | * | |
409 | * Permit data-storage cache objects to be pinned in the cache. | |
410 | * | |
efc930fa | 411 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
412 | * description. |
413 | */ | |
414 | static inline | |
415 | int fscache_pin_cookie(struct fscache_cookie *cookie) | |
416 | { | |
417 | return -ENOBUFS; | |
418 | } | |
419 | ||
420 | /** | |
421 | * fscache_pin_cookie - Unpin a data-storage cache object in its cache | |
422 | * @cookie: The cookie representing the cache object | |
423 | * | |
424 | * Permit data-storage cache objects to be unpinned from the cache. | |
425 | * | |
efc930fa | 426 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
427 | * description. |
428 | */ | |
429 | static inline | |
430 | void fscache_unpin_cookie(struct fscache_cookie *cookie) | |
431 | { | |
432 | } | |
433 | ||
434 | /** | |
435 | * fscache_attr_changed - Notify cache that an object's attributes changed | |
436 | * @cookie: The cookie representing the cache object | |
437 | * | |
438 | * Send a notification to the cache indicating that an object's attributes have | |
439 | * changed. This includes the data size. These attributes will be obtained | |
440 | * through the get_attr() cookie definition op. | |
441 | * | |
efc930fa | 442 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
443 | * description. |
444 | */ | |
445 | static inline | |
446 | int fscache_attr_changed(struct fscache_cookie *cookie) | |
447 | { | |
94d30ae9 | 448 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
449 | return __fscache_attr_changed(cookie); |
450 | else | |
451 | return -ENOBUFS; | |
2d6fff63 DH |
452 | } |
453 | ||
ef778e7a DH |
454 | /** |
455 | * fscache_invalidate - Notify cache that an object needs invalidation | |
456 | * @cookie: The cookie representing the cache object | |
457 | * | |
458 | * Notify the cache that an object is needs to be invalidated and that it | |
459 | * should abort any retrievals or stores it is doing on the cache. The object | |
460 | * is then marked non-caching until such time as the invalidation is complete. | |
461 | * | |
462 | * This can be called with spinlocks held. | |
463 | * | |
efc930fa | 464 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
ef778e7a DH |
465 | * description. |
466 | */ | |
467 | static inline | |
468 | void fscache_invalidate(struct fscache_cookie *cookie) | |
469 | { | |
94d30ae9 | 470 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ef778e7a DH |
471 | __fscache_invalidate(cookie); |
472 | } | |
473 | ||
474 | /** | |
475 | * fscache_wait_on_invalidate - Wait for invalidation to complete | |
476 | * @cookie: The cookie representing the cache object | |
477 | * | |
478 | * Wait for the invalidation of an object to complete. | |
479 | * | |
efc930fa | 480 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
ef778e7a DH |
481 | * description. |
482 | */ | |
483 | static inline | |
484 | void fscache_wait_on_invalidate(struct fscache_cookie *cookie) | |
485 | { | |
486 | if (fscache_cookie_valid(cookie)) | |
487 | __fscache_wait_on_invalidate(cookie); | |
488 | } | |
489 | ||
2d6fff63 DH |
490 | /** |
491 | * fscache_reserve_space - Reserve data space for a cached object | |
492 | * @cookie: The cookie representing the cache object | |
493 | * @i_size: The amount of space to be reserved | |
494 | * | |
495 | * Reserve an amount of space in the cache for the cache object attached to a | |
496 | * cookie so that a write to that object within the space can always be | |
497 | * honoured. | |
498 | * | |
efc930fa | 499 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
500 | * description. |
501 | */ | |
502 | static inline | |
503 | int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) | |
504 | { | |
505 | return -ENOBUFS; | |
506 | } | |
507 | ||
26aaeffc DH |
508 | #ifdef FSCACHE_USE_NEW_IO_API |
509 | ||
510 | /** | |
511 | * fscache_begin_read_operation - Begin a read operation for the netfs lib | |
512 | * @rreq: The read request being undertaken | |
513 | * @cookie: The cookie representing the cache object | |
514 | * | |
515 | * Begin a read operation on behalf of the netfs helper library. @rreq | |
516 | * indicates the read request to which the operation state should be attached; | |
517 | * @cookie indicates the cache object that will be accessed. | |
518 | * | |
519 | * This is intended to be called from the ->begin_cache_operation() netfs lib | |
520 | * operation as implemented by the network filesystem. | |
521 | * | |
522 | * Returns: | |
523 | * * 0 - Success | |
524 | * * -ENOBUFS - No caching available | |
525 | * * Other error code from the cache, such as -ENOMEM. | |
526 | */ | |
527 | static inline | |
528 | int fscache_begin_read_operation(struct netfs_read_request *rreq, | |
529 | struct fscache_cookie *cookie) | |
530 | { | |
531 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) | |
532 | return __fscache_begin_read_operation(rreq, cookie); | |
533 | return -ENOBUFS; | |
534 | } | |
535 | ||
536 | #else /* FSCACHE_USE_NEW_IO_API */ | |
537 | ||
2d6fff63 DH |
538 | /** |
539 | * fscache_read_or_alloc_page - Read a page from the cache or allocate a block | |
540 | * in which to store it | |
541 | * @cookie: The cookie representing the cache object | |
542 | * @page: The netfs page to fill if possible | |
543 | * @end_io_func: The callback to invoke when and if the page is filled | |
544 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
545 | * @gfp: The conditions under which memory allocation should be made | |
546 | * | |
547 | * Read a page from the cache, or if that's not possible make a potential | |
548 | * one-block reservation in the cache into which the page may be stored once | |
549 | * fetched from the server. | |
550 | * | |
551 | * If the page is not backed by the cache object, or if it there's some reason | |
552 | * it can't be, -ENOBUFS will be returned and nothing more will be done for | |
553 | * that page. | |
554 | * | |
555 | * Else, if that page is backed by the cache, a read will be initiated directly | |
556 | * to the netfs's page and 0 will be returned by this function. The | |
557 | * end_io_func() callback will be invoked when the operation terminates on a | |
558 | * completion or failure. Note that the callback may be invoked before the | |
559 | * return. | |
560 | * | |
561 | * Else, if the page is unbacked, -ENODATA is returned and a block may have | |
562 | * been allocated in the cache. | |
563 | * | |
efc930fa | 564 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
565 | * description. |
566 | */ | |
567 | static inline | |
568 | int fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
569 | struct page *page, | |
570 | fscache_rw_complete_t end_io_func, | |
571 | void *context, | |
572 | gfp_t gfp) | |
573 | { | |
94d30ae9 | 574 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
575 | return __fscache_read_or_alloc_page(cookie, page, end_io_func, |
576 | context, gfp); | |
577 | else | |
578 | return -ENOBUFS; | |
2d6fff63 DH |
579 | } |
580 | ||
581 | /** | |
582 | * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate | |
583 | * blocks in which to store them | |
584 | * @cookie: The cookie representing the cache object | |
585 | * @mapping: The netfs inode mapping to which the pages will be attached | |
586 | * @pages: A list of potential netfs pages to be filled | |
49a3df80 | 587 | * @nr_pages: Number of pages to be read and/or allocated |
2d6fff63 DH |
588 | * @end_io_func: The callback to invoke when and if each page is filled |
589 | * @context: An arbitrary piece of data to pass on to end_io_func() | |
590 | * @gfp: The conditions under which memory allocation should be made | |
591 | * | |
592 | * Read a set of pages from the cache, or if that's not possible, attempt to | |
593 | * make a potential one-block reservation for each page in the cache into which | |
594 | * that page may be stored once fetched from the server. | |
595 | * | |
596 | * If some pages are not backed by the cache object, or if it there's some | |
597 | * reason they can't be, -ENOBUFS will be returned and nothing more will be | |
598 | * done for that pages. | |
599 | * | |
600 | * Else, if some of the pages are backed by the cache, a read will be initiated | |
601 | * directly to the netfs's page and 0 will be returned by this function. The | |
602 | * end_io_func() callback will be invoked when the operation terminates on a | |
603 | * completion or failure. Note that the callback may be invoked before the | |
604 | * return. | |
605 | * | |
606 | * Else, if a page is unbacked, -ENODATA is returned and a block may have | |
607 | * been allocated in the cache. | |
608 | * | |
609 | * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in | |
610 | * regard to different pages, the return values are prioritised in that order. | |
611 | * Any pages submitted for reading are removed from the pages list. | |
612 | * | |
efc930fa | 613 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
614 | * description. |
615 | */ | |
616 | static inline | |
617 | int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
618 | struct address_space *mapping, | |
619 | struct list_head *pages, | |
620 | unsigned *nr_pages, | |
621 | fscache_rw_complete_t end_io_func, | |
622 | void *context, | |
623 | gfp_t gfp) | |
624 | { | |
94d30ae9 | 625 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
626 | return __fscache_read_or_alloc_pages(cookie, mapping, pages, |
627 | nr_pages, end_io_func, | |
628 | context, gfp); | |
629 | else | |
630 | return -ENOBUFS; | |
2d6fff63 DH |
631 | } |
632 | ||
633 | /** | |
634 | * fscache_alloc_page - Allocate a block in which to store a page | |
635 | * @cookie: The cookie representing the cache object | |
636 | * @page: The netfs page to allocate a page for | |
637 | * @gfp: The conditions under which memory allocation should be made | |
638 | * | |
639 | * Request Allocation a block in the cache in which to store a netfs page | |
640 | * without retrieving any contents from the cache. | |
641 | * | |
642 | * If the page is not backed by a file then -ENOBUFS will be returned and | |
643 | * nothing more will be done, and no reservation will be made. | |
644 | * | |
645 | * Else, a block will be allocated if one wasn't already, and 0 will be | |
646 | * returned | |
647 | * | |
efc930fa | 648 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
649 | * description. |
650 | */ | |
651 | static inline | |
652 | int fscache_alloc_page(struct fscache_cookie *cookie, | |
653 | struct page *page, | |
654 | gfp_t gfp) | |
655 | { | |
94d30ae9 | 656 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
b5108822 DH |
657 | return __fscache_alloc_page(cookie, page, gfp); |
658 | else | |
659 | return -ENOBUFS; | |
2d6fff63 DH |
660 | } |
661 | ||
5a6f282a MT |
662 | /** |
663 | * fscache_readpages_cancel - Cancel read/alloc on pages | |
664 | * @cookie: The cookie representing the inode's cache object. | |
665 | * @pages: The netfs pages that we canceled write on in readpages() | |
666 | * | |
667 | * Uncache/unreserve the pages reserved earlier in readpages() via | |
668 | * fscache_readpages_or_alloc() and similar. In most successful caches in | |
669 | * readpages() this doesn't do anything. In cases when the underlying netfs's | |
670 | * readahead failed we need to clean up the pagelist (unmark and uncache). | |
671 | * | |
672 | * This function may sleep as it may have to clean up disk state. | |
673 | */ | |
674 | static inline | |
675 | void fscache_readpages_cancel(struct fscache_cookie *cookie, | |
676 | struct list_head *pages) | |
677 | { | |
678 | if (fscache_cookie_valid(cookie)) | |
679 | __fscache_readpages_cancel(cookie, pages); | |
680 | } | |
681 | ||
2d6fff63 DH |
682 | /** |
683 | * fscache_write_page - Request storage of a page in the cache | |
684 | * @cookie: The cookie representing the cache object | |
685 | * @page: The netfs page to store | |
ee1235a9 | 686 | * @object_size: Updated size of object |
2d6fff63 DH |
687 | * @gfp: The conditions under which memory allocation should be made |
688 | * | |
689 | * Request the contents of the netfs page be written into the cache. This | |
690 | * request may be ignored if no cache block is currently allocated, in which | |
691 | * case it will return -ENOBUFS. | |
692 | * | |
693 | * If a cache block was already allocated, a write will be initiated and 0 will | |
694 | * be returned. The PG_fscache_write page bit is set immediately and will then | |
695 | * be cleared at the completion of the write to indicate the success or failure | |
696 | * of the operation. Note that the completion may happen before the return. | |
697 | * | |
efc930fa | 698 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
699 | * description. |
700 | */ | |
701 | static inline | |
702 | int fscache_write_page(struct fscache_cookie *cookie, | |
703 | struct page *page, | |
ee1235a9 | 704 | loff_t object_size, |
2d6fff63 DH |
705 | gfp_t gfp) |
706 | { | |
94d30ae9 | 707 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
ee1235a9 | 708 | return __fscache_write_page(cookie, page, object_size, gfp); |
b5108822 DH |
709 | else |
710 | return -ENOBUFS; | |
2d6fff63 DH |
711 | } |
712 | ||
713 | /** | |
714 | * fscache_uncache_page - Indicate that caching is no longer required on a page | |
715 | * @cookie: The cookie representing the cache object | |
716 | * @page: The netfs page that was being cached. | |
717 | * | |
718 | * Tell the cache that we no longer want a page to be cached and that it should | |
719 | * remove any knowledge of the netfs page it may have. | |
720 | * | |
721 | * Note that this cannot cancel any outstanding I/O operations between this | |
722 | * page and the cache. | |
723 | * | |
efc930fa | 724 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
725 | * description. |
726 | */ | |
727 | static inline | |
728 | void fscache_uncache_page(struct fscache_cookie *cookie, | |
729 | struct page *page) | |
730 | { | |
b5108822 DH |
731 | if (fscache_cookie_valid(cookie)) |
732 | __fscache_uncache_page(cookie, page); | |
2d6fff63 DH |
733 | } |
734 | ||
735 | /** | |
736 | * fscache_check_page_write - Ask if a page is being writing to the cache | |
737 | * @cookie: The cookie representing the cache object | |
738 | * @page: The netfs page that is being cached. | |
739 | * | |
740 | * Ask the cache if a page is being written to the cache. | |
741 | * | |
efc930fa | 742 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
743 | * description. |
744 | */ | |
745 | static inline | |
746 | bool fscache_check_page_write(struct fscache_cookie *cookie, | |
747 | struct page *page) | |
748 | { | |
b5108822 DH |
749 | if (fscache_cookie_valid(cookie)) |
750 | return __fscache_check_page_write(cookie, page); | |
2d6fff63 DH |
751 | return false; |
752 | } | |
753 | ||
754 | /** | |
755 | * fscache_wait_on_page_write - Wait for a page to complete writing to the cache | |
756 | * @cookie: The cookie representing the cache object | |
757 | * @page: The netfs page that is being cached. | |
758 | * | |
759 | * Ask the cache to wake us up when a page is no longer being written to the | |
760 | * cache. | |
761 | * | |
efc930fa | 762 | * See Documentation/filesystems/caching/netfs-api.rst for a complete |
2d6fff63 DH |
763 | * description. |
764 | */ | |
765 | static inline | |
766 | void fscache_wait_on_page_write(struct fscache_cookie *cookie, | |
767 | struct page *page) | |
768 | { | |
b5108822 DH |
769 | if (fscache_cookie_valid(cookie)) |
770 | __fscache_wait_on_page_write(cookie, page); | |
2d6fff63 DH |
771 | } |
772 | ||
201a1542 DH |
773 | /** |
774 | * fscache_maybe_release_page - Consider releasing a page, cancelling a store | |
775 | * @cookie: The cookie representing the cache object | |
776 | * @page: The netfs page that is being cached. | |
777 | * @gfp: The gfp flags passed to releasepage() | |
778 | * | |
779 | * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's | |
780 | * releasepage() call. A storage request on the page may cancelled if it is | |
781 | * not currently being processed. | |
782 | * | |
783 | * The function returns true if the page no longer has a storage request on it, | |
784 | * and false if a storage request is left in place. If true is returned, the | |
785 | * page will have been passed to fscache_uncache_page(). If false is returned | |
786 | * the page cannot be freed yet. | |
787 | */ | |
788 | static inline | |
789 | bool fscache_maybe_release_page(struct fscache_cookie *cookie, | |
790 | struct page *page, | |
791 | gfp_t gfp) | |
792 | { | |
793 | if (fscache_cookie_valid(cookie) && PageFsCache(page)) | |
794 | return __fscache_maybe_release_page(cookie, page, gfp); | |
98801506 | 795 | return true; |
201a1542 DH |
796 | } |
797 | ||
c902ce1b DH |
798 | /** |
799 | * fscache_uncache_all_inode_pages - Uncache all an inode's pages | |
800 | * @cookie: The cookie representing the inode's cache object. | |
801 | * @inode: The inode to uncache pages from. | |
802 | * | |
803 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them | |
804 | * to be associated with the given cookie. | |
805 | * | |
806 | * This function may sleep. It will wait for pages that are being written out | |
807 | * and will wait whilst the PG_fscache mark is removed by the cache. | |
808 | */ | |
809 | static inline | |
810 | void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, | |
811 | struct inode *inode) | |
812 | { | |
813 | if (fscache_cookie_valid(cookie)) | |
814 | __fscache_uncache_all_inode_pages(cookie, inode); | |
815 | } | |
816 | ||
26aaeffc DH |
817 | #endif /* FSCACHE_USE_NEW_IO_API */ |
818 | ||
94d30ae9 DH |
819 | /** |
820 | * fscache_disable_cookie - Disable a cookie | |
821 | * @cookie: The cookie representing the cache object | |
402cb8dd | 822 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
94d30ae9 DH |
823 | * @invalidate: Invalidate the backing object |
824 | * | |
825 | * Disable a cookie from accepting further alloc, read, write, invalidate, | |
826 | * update or acquire operations. Outstanding operations can still be waited | |
827 | * upon and pages can still be uncached and the cookie relinquished. | |
828 | * | |
829 | * This will not return until all outstanding operations have completed. | |
830 | * | |
831 | * If @invalidate is set, then the backing object will be invalidated and | |
832 | * detached, otherwise it will just be detached. | |
402cb8dd DH |
833 | * |
834 | * If @aux_data is set, then auxiliary data will be updated from that. | |
94d30ae9 DH |
835 | */ |
836 | static inline | |
402cb8dd DH |
837 | void fscache_disable_cookie(struct fscache_cookie *cookie, |
838 | const void *aux_data, | |
839 | bool invalidate) | |
94d30ae9 DH |
840 | { |
841 | if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) | |
402cb8dd | 842 | __fscache_disable_cookie(cookie, aux_data, invalidate); |
94d30ae9 DH |
843 | } |
844 | ||
845 | /** | |
846 | * fscache_enable_cookie - Reenable a cookie | |
847 | * @cookie: The cookie representing the cache object | |
402cb8dd | 848 | * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
ee1235a9 | 849 | * @object_size: Current size of object |
94d30ae9 DH |
850 | * @can_enable: A function to permit enablement once lock is held |
851 | * @data: Data for can_enable() | |
852 | * | |
853 | * Reenable a previously disabled cookie, allowing it to accept further alloc, | |
854 | * read, write, invalidate, update or acquire operations. An attempt will be | |
402cb8dd DH |
855 | * made to immediately reattach the cookie to a backing object. If @aux_data |
856 | * is set, the auxiliary data attached to the cookie will be updated. | |
94d30ae9 DH |
857 | * |
858 | * The can_enable() function is called (if not NULL) once the enablement lock | |
859 | * is held to rule on whether enablement is still permitted to go ahead. | |
860 | */ | |
861 | static inline | |
862 | void fscache_enable_cookie(struct fscache_cookie *cookie, | |
402cb8dd | 863 | const void *aux_data, |
ee1235a9 | 864 | loff_t object_size, |
94d30ae9 DH |
865 | bool (*can_enable)(void *data), |
866 | void *data) | |
867 | { | |
868 | if (fscache_cookie_valid(cookie) && !fscache_cookie_enabled(cookie)) | |
ee1235a9 DH |
869 | __fscache_enable_cookie(cookie, aux_data, object_size, |
870 | can_enable, data); | |
94d30ae9 DH |
871 | } |
872 | ||
2d6fff63 | 873 | #endif /* _LINUX_FSCACHE_H */ |