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David Howells2d6fff62009-04-03 16:42:36 +01001/* 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
48struct pagevec;
49struct fscache_cache_tag;
50struct fscache_cookie;
51struct fscache_netfs;
52
53typedef void (*fscache_rw_complete_t)(struct page *page,
54 void *context,
55 int error);
56
57/* result of index entry consultation */
58enum 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 */
67struct 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
Suresh Jayaramanab0cfb92010-07-06 18:12:39 +053088 * - should return the amount of data stored
David Howells2d6fff62009-04-03 16:42:36 +010089 * - 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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300105 /* get the auxiliary data from netfs data
David Howells2d6fff62009-04-03 16:42:36 +0100106 * - this function can be absent if the index carries no state data
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300107 * - should store the auxiliary data in the buffer
David Howells2d6fff62009-04-03 16:42:36 +0100108 * - 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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300120 * presented, as is the auxiliary data
David Howells2d6fff62009-04-03 16:42:36 +0100121 */
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
David Howellsc4d6d8d2012-12-20 21:52:32 +0000138 /* indicate page that now have cache metadata retained
139 * - this function should mark the specified page as now being cached
140 * - the page will have been marked with PG_fscache before this is
David Howells2d6fff62009-04-03 16:42:36 +0100141 * called, so this is optional
142 */
David Howellsc4d6d8d2012-12-20 21:52:32 +0000143 void (*mark_page_cached)(void *cookie_netfs_data,
144 struct address_space *mapping,
145 struct page *page);
David Howells2d6fff62009-04-03 16:42:36 +0100146
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 */
162struct 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 */
David Howells726dd7f2009-04-03 16:42:38 +0100176extern int __fscache_register_netfs(struct fscache_netfs *);
177extern void __fscache_unregister_netfs(struct fscache_netfs *);
David Howells0e04d4c2009-04-03 16:42:37 +0100178extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *);
179extern void __fscache_release_cache_tag(struct fscache_cache_tag *);
David Howells2d6fff62009-04-03 16:42:36 +0100180
David Howellsccc4fc32009-04-03 16:42:38 +0100181extern struct fscache_cookie *__fscache_acquire_cookie(
182 struct fscache_cookie *,
183 const struct fscache_cookie_def *,
184 void *);
185extern void __fscache_relinquish_cookie(struct fscache_cookie *, int);
186extern void __fscache_update_cookie(struct fscache_cookie *);
David Howellsb5108822009-04-03 16:42:39 +0100187extern int __fscache_attr_changed(struct fscache_cookie *);
David Howellsef778e72012-12-20 21:52:36 +0000188extern void __fscache_invalidate(struct fscache_cookie *);
189extern void __fscache_wait_on_invalidate(struct fscache_cookie *);
David Howellsb5108822009-04-03 16:42:39 +0100190extern int __fscache_read_or_alloc_page(struct fscache_cookie *,
191 struct page *,
192 fscache_rw_complete_t,
193 void *,
194 gfp_t);
195extern int __fscache_read_or_alloc_pages(struct fscache_cookie *,
196 struct address_space *,
197 struct list_head *,
198 unsigned *,
199 fscache_rw_complete_t,
200 void *,
201 gfp_t);
202extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t);
203extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t);
204extern void __fscache_uncache_page(struct fscache_cookie *, struct page *);
205extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *);
206extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *);
David Howells201a1542009-11-19 18:11:35 +0000207extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *,
208 gfp_t);
David Howellsc902ce12011-07-07 12:19:48 +0100209extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *,
210 struct inode *);
David Howellsccc4fc32009-04-03 16:42:38 +0100211
David Howells2d6fff62009-04-03 16:42:36 +0100212/**
213 * fscache_register_netfs - Register a filesystem as desiring caching services
214 * @netfs: The description of the filesystem
215 *
216 * Register a filesystem as desiring caching services if they're available.
217 *
218 * See Documentation/filesystems/caching/netfs-api.txt for a complete
219 * description.
220 */
221static inline
222int fscache_register_netfs(struct fscache_netfs *netfs)
223{
David Howells726dd7f2009-04-03 16:42:38 +0100224 if (fscache_available())
225 return __fscache_register_netfs(netfs);
226 else
227 return 0;
David Howells2d6fff62009-04-03 16:42:36 +0100228}
229
230/**
231 * fscache_unregister_netfs - Indicate that a filesystem no longer desires
232 * caching services
233 * @netfs: The description of the filesystem
234 *
235 * Indicate that a filesystem no longer desires caching services for the
236 * moment.
237 *
238 * See Documentation/filesystems/caching/netfs-api.txt for a complete
239 * description.
240 */
241static inline
242void fscache_unregister_netfs(struct fscache_netfs *netfs)
243{
David Howells726dd7f2009-04-03 16:42:38 +0100244 if (fscache_available())
245 __fscache_unregister_netfs(netfs);
David Howells2d6fff62009-04-03 16:42:36 +0100246}
247
248/**
249 * fscache_lookup_cache_tag - Look up a cache tag
250 * @name: The name of the tag to search for
251 *
252 * Acquire a specific cache referral tag that can be used to select a specific
253 * cache in which to cache an index.
254 *
255 * See Documentation/filesystems/caching/netfs-api.txt for a complete
256 * description.
257 */
258static inline
259struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name)
260{
David Howells0e04d4c2009-04-03 16:42:37 +0100261 if (fscache_available())
262 return __fscache_lookup_cache_tag(name);
263 else
264 return NULL;
David Howells2d6fff62009-04-03 16:42:36 +0100265}
266
267/**
268 * fscache_release_cache_tag - Release a cache tag
269 * @tag: The tag to release
270 *
271 * Release a reference to a cache referral tag previously looked up.
272 *
273 * See Documentation/filesystems/caching/netfs-api.txt for a complete
274 * description.
275 */
276static inline
277void fscache_release_cache_tag(struct fscache_cache_tag *tag)
278{
David Howells0e04d4c2009-04-03 16:42:37 +0100279 if (fscache_available())
280 __fscache_release_cache_tag(tag);
David Howells2d6fff62009-04-03 16:42:36 +0100281}
282
283/**
284 * fscache_acquire_cookie - Acquire a cookie to represent a cache object
285 * @parent: The cookie that's to be the parent of this one
286 * @def: A description of the cache object, including callback operations
287 * @netfs_data: An arbitrary piece of data to be kept in the cookie to
288 * represent the cache object to the netfs
289 *
290 * This function is used to inform FS-Cache about part of an index hierarchy
291 * that can be used to locate files. This is done by requesting a cookie for
292 * each index in the path to the file.
293 *
294 * See Documentation/filesystems/caching/netfs-api.txt for a complete
295 * description.
296 */
297static inline
298struct fscache_cookie *fscache_acquire_cookie(
299 struct fscache_cookie *parent,
300 const struct fscache_cookie_def *def,
301 void *netfs_data)
302{
David Howellsccc4fc32009-04-03 16:42:38 +0100303 if (fscache_cookie_valid(parent))
304 return __fscache_acquire_cookie(parent, def, netfs_data);
305 else
306 return NULL;
David Howells2d6fff62009-04-03 16:42:36 +0100307}
308
309/**
310 * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding
311 * it
312 * @cookie: The cookie being returned
313 * @retire: True if the cache object the cookie represents is to be discarded
314 *
315 * This function returns a cookie to the cache, forcibly discarding the
316 * associated cache object if retire is set to true.
317 *
318 * See Documentation/filesystems/caching/netfs-api.txt for a complete
319 * description.
320 */
321static inline
322void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
323{
David Howellsccc4fc32009-04-03 16:42:38 +0100324 if (fscache_cookie_valid(cookie))
325 __fscache_relinquish_cookie(cookie, retire);
David Howells2d6fff62009-04-03 16:42:36 +0100326}
327
328/**
329 * fscache_update_cookie - Request that a cache object be updated
330 * @cookie: The cookie representing the cache object
331 *
332 * Request an update of the index data for the cache object associated with the
333 * cookie.
334 *
335 * See Documentation/filesystems/caching/netfs-api.txt for a complete
336 * description.
337 */
338static inline
339void fscache_update_cookie(struct fscache_cookie *cookie)
340{
David Howellsccc4fc32009-04-03 16:42:38 +0100341 if (fscache_cookie_valid(cookie))
342 __fscache_update_cookie(cookie);
David Howells2d6fff62009-04-03 16:42:36 +0100343}
344
345/**
346 * fscache_pin_cookie - Pin a data-storage cache object in its cache
347 * @cookie: The cookie representing the cache object
348 *
349 * Permit data-storage cache objects to be pinned in the cache.
350 *
351 * See Documentation/filesystems/caching/netfs-api.txt for a complete
352 * description.
353 */
354static inline
355int fscache_pin_cookie(struct fscache_cookie *cookie)
356{
357 return -ENOBUFS;
358}
359
360/**
361 * fscache_pin_cookie - Unpin a data-storage cache object in its cache
362 * @cookie: The cookie representing the cache object
363 *
364 * Permit data-storage cache objects to be unpinned from the cache.
365 *
366 * See Documentation/filesystems/caching/netfs-api.txt for a complete
367 * description.
368 */
369static inline
370void fscache_unpin_cookie(struct fscache_cookie *cookie)
371{
372}
373
374/**
375 * fscache_attr_changed - Notify cache that an object's attributes changed
376 * @cookie: The cookie representing the cache object
377 *
378 * Send a notification to the cache indicating that an object's attributes have
379 * changed. This includes the data size. These attributes will be obtained
380 * through the get_attr() cookie definition op.
381 *
382 * See Documentation/filesystems/caching/netfs-api.txt for a complete
383 * description.
384 */
385static inline
386int fscache_attr_changed(struct fscache_cookie *cookie)
387{
David Howellsb5108822009-04-03 16:42:39 +0100388 if (fscache_cookie_valid(cookie))
389 return __fscache_attr_changed(cookie);
390 else
391 return -ENOBUFS;
David Howells2d6fff62009-04-03 16:42:36 +0100392}
393
394/**
David Howellsef778e72012-12-20 21:52:36 +0000395 * fscache_invalidate - Notify cache that an object needs invalidation
396 * @cookie: The cookie representing the cache object
397 *
398 * Notify the cache that an object is needs to be invalidated and that it
399 * should abort any retrievals or stores it is doing on the cache. The object
400 * is then marked non-caching until such time as the invalidation is complete.
401 *
402 * This can be called with spinlocks held.
403 *
404 * See Documentation/filesystems/caching/netfs-api.txt for a complete
405 * description.
406 */
407static inline
408void fscache_invalidate(struct fscache_cookie *cookie)
409{
410 if (fscache_cookie_valid(cookie))
411 __fscache_invalidate(cookie);
412}
413
414/**
415 * fscache_wait_on_invalidate - Wait for invalidation to complete
416 * @cookie: The cookie representing the cache object
417 *
418 * Wait for the invalidation of an object to complete.
419 *
420 * See Documentation/filesystems/caching/netfs-api.txt for a complete
421 * description.
422 */
423static inline
424void fscache_wait_on_invalidate(struct fscache_cookie *cookie)
425{
426 if (fscache_cookie_valid(cookie))
427 __fscache_wait_on_invalidate(cookie);
428}
429
430/**
David Howells2d6fff62009-04-03 16:42:36 +0100431 * fscache_reserve_space - Reserve data space for a cached object
432 * @cookie: The cookie representing the cache object
433 * @i_size: The amount of space to be reserved
434 *
435 * Reserve an amount of space in the cache for the cache object attached to a
436 * cookie so that a write to that object within the space can always be
437 * honoured.
438 *
439 * See Documentation/filesystems/caching/netfs-api.txt for a complete
440 * description.
441 */
442static inline
443int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size)
444{
445 return -ENOBUFS;
446}
447
448/**
449 * fscache_read_or_alloc_page - Read a page from the cache or allocate a block
450 * in which to store it
451 * @cookie: The cookie representing the cache object
452 * @page: The netfs page to fill if possible
453 * @end_io_func: The callback to invoke when and if the page is filled
454 * @context: An arbitrary piece of data to pass on to end_io_func()
455 * @gfp: The conditions under which memory allocation should be made
456 *
457 * Read a page from the cache, or if that's not possible make a potential
458 * one-block reservation in the cache into which the page may be stored once
459 * fetched from the server.
460 *
461 * If the page is not backed by the cache object, or if it there's some reason
462 * it can't be, -ENOBUFS will be returned and nothing more will be done for
463 * that page.
464 *
465 * Else, if that page is backed by the cache, a read will be initiated directly
466 * to the netfs's page and 0 will be returned by this function. The
467 * end_io_func() callback will be invoked when the operation terminates on a
468 * completion or failure. Note that the callback may be invoked before the
469 * return.
470 *
471 * Else, if the page is unbacked, -ENODATA is returned and a block may have
472 * been allocated in the cache.
473 *
474 * See Documentation/filesystems/caching/netfs-api.txt for a complete
475 * description.
476 */
477static inline
478int fscache_read_or_alloc_page(struct fscache_cookie *cookie,
479 struct page *page,
480 fscache_rw_complete_t end_io_func,
481 void *context,
482 gfp_t gfp)
483{
David Howellsb5108822009-04-03 16:42:39 +0100484 if (fscache_cookie_valid(cookie))
485 return __fscache_read_or_alloc_page(cookie, page, end_io_func,
486 context, gfp);
487 else
488 return -ENOBUFS;
David Howells2d6fff62009-04-03 16:42:36 +0100489}
490
491/**
492 * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate
493 * blocks in which to store them
494 * @cookie: The cookie representing the cache object
495 * @mapping: The netfs inode mapping to which the pages will be attached
496 * @pages: A list of potential netfs pages to be filled
Suresh Jayaraman49a3df82010-07-06 18:29:45 +0530497 * @nr_pages: Number of pages to be read and/or allocated
David Howells2d6fff62009-04-03 16:42:36 +0100498 * @end_io_func: The callback to invoke when and if each page is filled
499 * @context: An arbitrary piece of data to pass on to end_io_func()
500 * @gfp: The conditions under which memory allocation should be made
501 *
502 * Read a set of pages from the cache, or if that's not possible, attempt to
503 * make a potential one-block reservation for each page in the cache into which
504 * that page may be stored once fetched from the server.
505 *
506 * If some pages are not backed by the cache object, or if it there's some
507 * reason they can't be, -ENOBUFS will be returned and nothing more will be
508 * done for that pages.
509 *
510 * Else, if some of the pages are backed by the cache, a read will be initiated
511 * directly to the netfs's page and 0 will be returned by this function. The
512 * end_io_func() callback will be invoked when the operation terminates on a
513 * completion or failure. Note that the callback may be invoked before the
514 * return.
515 *
516 * Else, if a page is unbacked, -ENODATA is returned and a block may have
517 * been allocated in the cache.
518 *
519 * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in
520 * regard to different pages, the return values are prioritised in that order.
521 * Any pages submitted for reading are removed from the pages list.
522 *
523 * See Documentation/filesystems/caching/netfs-api.txt for a complete
524 * description.
525 */
526static inline
527int fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
528 struct address_space *mapping,
529 struct list_head *pages,
530 unsigned *nr_pages,
531 fscache_rw_complete_t end_io_func,
532 void *context,
533 gfp_t gfp)
534{
David Howellsb5108822009-04-03 16:42:39 +0100535 if (fscache_cookie_valid(cookie))
536 return __fscache_read_or_alloc_pages(cookie, mapping, pages,
537 nr_pages, end_io_func,
538 context, gfp);
539 else
540 return -ENOBUFS;
David Howells2d6fff62009-04-03 16:42:36 +0100541}
542
543/**
544 * fscache_alloc_page - Allocate a block in which to store a page
545 * @cookie: The cookie representing the cache object
546 * @page: The netfs page to allocate a page for
547 * @gfp: The conditions under which memory allocation should be made
548 *
549 * Request Allocation a block in the cache in which to store a netfs page
550 * without retrieving any contents from the cache.
551 *
552 * If the page is not backed by a file then -ENOBUFS will be returned and
553 * nothing more will be done, and no reservation will be made.
554 *
555 * Else, a block will be allocated if one wasn't already, and 0 will be
556 * returned
557 *
558 * See Documentation/filesystems/caching/netfs-api.txt for a complete
559 * description.
560 */
561static inline
562int fscache_alloc_page(struct fscache_cookie *cookie,
563 struct page *page,
564 gfp_t gfp)
565{
David Howellsb5108822009-04-03 16:42:39 +0100566 if (fscache_cookie_valid(cookie))
567 return __fscache_alloc_page(cookie, page, gfp);
568 else
569 return -ENOBUFS;
David Howells2d6fff62009-04-03 16:42:36 +0100570}
571
572/**
573 * fscache_write_page - Request storage of a page in the cache
574 * @cookie: The cookie representing the cache object
575 * @page: The netfs page to store
576 * @gfp: The conditions under which memory allocation should be made
577 *
578 * Request the contents of the netfs page be written into the cache. This
579 * request may be ignored if no cache block is currently allocated, in which
580 * case it will return -ENOBUFS.
581 *
582 * If a cache block was already allocated, a write will be initiated and 0 will
583 * be returned. The PG_fscache_write page bit is set immediately and will then
584 * be cleared at the completion of the write to indicate the success or failure
585 * of the operation. Note that the completion may happen before the return.
586 *
587 * See Documentation/filesystems/caching/netfs-api.txt for a complete
588 * description.
589 */
590static inline
591int fscache_write_page(struct fscache_cookie *cookie,
592 struct page *page,
593 gfp_t gfp)
594{
David Howellsb5108822009-04-03 16:42:39 +0100595 if (fscache_cookie_valid(cookie))
596 return __fscache_write_page(cookie, page, gfp);
597 else
598 return -ENOBUFS;
David Howells2d6fff62009-04-03 16:42:36 +0100599}
600
601/**
602 * fscache_uncache_page - Indicate that caching is no longer required on a page
603 * @cookie: The cookie representing the cache object
604 * @page: The netfs page that was being cached.
605 *
606 * Tell the cache that we no longer want a page to be cached and that it should
607 * remove any knowledge of the netfs page it may have.
608 *
609 * Note that this cannot cancel any outstanding I/O operations between this
610 * page and the cache.
611 *
612 * See Documentation/filesystems/caching/netfs-api.txt for a complete
613 * description.
614 */
615static inline
616void fscache_uncache_page(struct fscache_cookie *cookie,
617 struct page *page)
618{
David Howellsb5108822009-04-03 16:42:39 +0100619 if (fscache_cookie_valid(cookie))
620 __fscache_uncache_page(cookie, page);
David Howells2d6fff62009-04-03 16:42:36 +0100621}
622
623/**
624 * fscache_check_page_write - Ask if a page is being writing to the cache
625 * @cookie: The cookie representing the cache object
626 * @page: The netfs page that is being cached.
627 *
628 * Ask the cache if a page is being written to the cache.
629 *
630 * See Documentation/filesystems/caching/netfs-api.txt for a complete
631 * description.
632 */
633static inline
634bool fscache_check_page_write(struct fscache_cookie *cookie,
635 struct page *page)
636{
David Howellsb5108822009-04-03 16:42:39 +0100637 if (fscache_cookie_valid(cookie))
638 return __fscache_check_page_write(cookie, page);
David Howells2d6fff62009-04-03 16:42:36 +0100639 return false;
640}
641
642/**
643 * fscache_wait_on_page_write - Wait for a page to complete writing to the cache
644 * @cookie: The cookie representing the cache object
645 * @page: The netfs page that is being cached.
646 *
647 * Ask the cache to wake us up when a page is no longer being written to the
648 * cache.
649 *
650 * See Documentation/filesystems/caching/netfs-api.txt for a complete
651 * description.
652 */
653static inline
654void fscache_wait_on_page_write(struct fscache_cookie *cookie,
655 struct page *page)
656{
David Howellsb5108822009-04-03 16:42:39 +0100657 if (fscache_cookie_valid(cookie))
658 __fscache_wait_on_page_write(cookie, page);
David Howells2d6fff62009-04-03 16:42:36 +0100659}
660
David Howells201a1542009-11-19 18:11:35 +0000661/**
662 * fscache_maybe_release_page - Consider releasing a page, cancelling a store
663 * @cookie: The cookie representing the cache object
664 * @page: The netfs page that is being cached.
665 * @gfp: The gfp flags passed to releasepage()
666 *
667 * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's
668 * releasepage() call. A storage request on the page may cancelled if it is
669 * not currently being processed.
670 *
671 * The function returns true if the page no longer has a storage request on it,
672 * and false if a storage request is left in place. If true is returned, the
673 * page will have been passed to fscache_uncache_page(). If false is returned
674 * the page cannot be freed yet.
675 */
676static inline
677bool fscache_maybe_release_page(struct fscache_cookie *cookie,
678 struct page *page,
679 gfp_t gfp)
680{
681 if (fscache_cookie_valid(cookie) && PageFsCache(page))
682 return __fscache_maybe_release_page(cookie, page, gfp);
683 return false;
684}
685
David Howellsc902ce12011-07-07 12:19:48 +0100686/**
687 * fscache_uncache_all_inode_pages - Uncache all an inode's pages
688 * @cookie: The cookie representing the inode's cache object.
689 * @inode: The inode to uncache pages from.
690 *
691 * Uncache all the pages in an inode that are marked PG_fscache, assuming them
692 * to be associated with the given cookie.
693 *
694 * This function may sleep. It will wait for pages that are being written out
695 * and will wait whilst the PG_fscache mark is removed by the cache.
696 */
697static inline
698void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
699 struct inode *inode)
700{
701 if (fscache_cookie_valid(cookie))
702 __fscache_uncache_all_inode_pages(cookie, inode);
703}
704
David Howells2d6fff62009-04-03 16:42:36 +0100705#endif /* _LINUX_FSCACHE_H */