1 /* General filesystem caching interface
2  *
3  * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  *
11  * NOTE!!! See:
12  *
13  *	Documentation/filesystems/caching/netfs-api.txt
14  *
15  * for a description of the network filesystem interface declared here.
16  */
17 
18 #ifndef _LINUX_FSCACHE_H
19 #define _LINUX_FSCACHE_H
20 
21 #include <linux/fs.h>
22 #include <linux/list.h>
23 #include <linux/pagemap.h>
24 #include <linux/pagevec.h>
25 
26 #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
27 #define fscache_available() (1)
28 #define fscache_cookie_valid(cookie) (cookie)
29 #else
30 #define fscache_available() (0)
31 #define fscache_cookie_valid(cookie) (0)
32 #endif
33 
34 
35 /*
36  * overload PG_private_2 to give us PG_fscache - this is used to indicate that
37  * a page is currently backed by a local disk cache
38  */
39 #define PageFsCache(page)		PagePrivate2((page))
40 #define SetPageFsCache(page)		SetPagePrivate2((page))
41 #define ClearPageFsCache(page)		ClearPagePrivate2((page))
42 #define TestSetPageFsCache(page)	TestSetPagePrivate2((page))
43 #define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
44 
45 /* pattern used to fill dead space in an index entry */
46 #define FSCACHE_INDEX_DEADFILL_PATTERN 0x79
47 
48 struct pagevec;
49 struct fscache_cache_tag;
50 struct fscache_cookie;
51 struct fscache_netfs;
52 
53 typedef void (*fscache_rw_complete_t)(struct page *page,
54 				      void *context,
55 				      int error);
56 
57 /* result of index entry consultation */
58 enum fscache_checkaux {
59 	FSCACHE_CHECKAUX_OKAY,		/* entry okay as is */
60 	FSCACHE_CHECKAUX_NEEDS_UPDATE,	/* entry requires update */
61 	FSCACHE_CHECKAUX_OBSOLETE,	/* entry requires deletion */
62 };
63 
64 /*
65  * fscache cookie definition
66  */
67 struct fscache_cookie_def {
68 	/* name of cookie type */
69 	char name[16];
70 
71 	/* cookie type */
72 	uint8_t type;
73 #define FSCACHE_COOKIE_TYPE_INDEX	0
74 #define FSCACHE_COOKIE_TYPE_DATAFILE	1
75 
76 	/* select the cache into which to insert an entry in this index
77 	 * - optional
78 	 * - should return a cache identifier or NULL to cause the cache to be
79 	 *   inherited from the parent if possible or the first cache picked
80 	 *   for a non-index file if not
81 	 */
82 	struct fscache_cache_tag *(*select_cache)(
83 		const void *parent_netfs_data,
84 		const void *cookie_netfs_data);
85 
86 	/* get an index key
87 	 * - should store the key data in the buffer
88 	 * - should return the amount of data stored
89 	 * - not permitted to return an error
90 	 * - the netfs data from the cookie being used as the source is
91 	 *   presented
92 	 */
93 	uint16_t (*get_key)(const void *cookie_netfs_data,
94 			    void *buffer,
95 			    uint16_t bufmax);
96 
97 	/* get certain file attributes from the netfs data
98 	 * - this function can be absent for an index
99 	 * - not permitted to return an error
100 	 * - the netfs data from the cookie being used as the source is
101 	 *   presented
102 	 */
103 	void (*get_attr)(const void *cookie_netfs_data, uint64_t *size);
104 
105 	/* get the auxiliary data from netfs data
106 	 * - this function can be absent if the index carries no state data
107 	 * - should store the auxiliary data in the buffer
108 	 * - should return the amount of amount stored
109 	 * - not permitted to return an error
110 	 * - the netfs data from the cookie being used as the source is
111 	 *   presented
112 	 */
113 	uint16_t (*get_aux)(const void *cookie_netfs_data,
114 			    void *buffer,
115 			    uint16_t bufmax);
116 
117 	/* consult the netfs about the state of an object
118 	 * - this function can be absent if the index carries no state data
119 	 * - the netfs data from the cookie being used as the target is
120 	 *   presented, as is the auxiliary data
121 	 */
122 	enum fscache_checkaux (*check_aux)(void *cookie_netfs_data,
123 					   const void *data,
124 					   uint16_t datalen);
125 
126 	/* get an extra reference on a read context
127 	 * - this function can be absent if the completion function doesn't
128 	 *   require a context
129 	 */
130 	void (*get_context)(void *cookie_netfs_data, void *context);
131 
132 	/* release an extra reference on a read context
133 	 * - this function can be absent if the completion function doesn't
134 	 *   require a context
135 	 */
136 	void (*put_context)(void *cookie_netfs_data, void *context);
137 
138 	/* indicate pages that now have cache metadata retained
139 	 * - this function should mark the specified pages as now being cached
140 	 * - the pages will have been marked with PG_fscache before this is
141 	 *   called, so this is optional
142 	 */
143 	void (*mark_pages_cached)(void *cookie_netfs_data,
144 				  struct address_space *mapping,
145 				  struct pagevec *cached_pvec);
146 
147 	/* indicate the cookie is no longer cached
148 	 * - this function is called when the backing store currently caching
149 	 *   a cookie is removed
150 	 * - the netfs should use this to clean up any markers indicating
151 	 *   cached pages
152 	 * - this is mandatory for any object that may have data
153 	 */
154 	void (*now_uncached)(void *cookie_netfs_data);
155 };
156 
157 /*
158  * fscache cached network filesystem type
159  * - name, version and ops must be filled in before registration
160  * - all other fields will be set during registration
161  */
162 struct fscache_netfs {
163 	uint32_t			version;	/* indexing version */
164 	const char			*name;		/* filesystem name */
165 	struct fscache_cookie		*primary_index;
166 	struct list_head		link;		/* internal link */
167 };
168 
169 /*
170  * slow-path functions for when there is actually caching available, and the
171  * netfs does actually have a valid token
172  * - these are not to be called directly
173  * - these are undefined symbols when FS-Cache is not configured and the
174  *   optimiser takes care of not using them
175  */
176 extern int __fscache_register_netfs(struct fscache_netfs *);
177 extern void __fscache_unregister_netfs(struct fscache_netfs *);
178 extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *);
179 extern void __fscache_release_cache_tag(struct fscache_cache_tag *);
180 
181 extern struct fscache_cookie *__fscache_acquire_cookie(
182 	struct fscache_cookie *,
183 	const struct fscache_cookie_def *,
184 	void *);
185 extern void __fscache_relinquish_cookie(struct fscache_cookie *, int);
186 extern void __fscache_update_cookie(struct fscache_cookie *);
187 extern int __fscache_attr_changed(struct fscache_cookie *);
188 extern int __fscache_read_or_alloc_page(struct fscache_cookie *,
189 					struct page *,
190 					fscache_rw_complete_t,
191 					void *,
192 					gfp_t);
193 extern int __fscache_read_or_alloc_pages(struct fscache_cookie *,
194 					 struct address_space *,
195 					 struct list_head *,
196 					 unsigned *,
197 					 fscache_rw_complete_t,
198 					 void *,
199 					 gfp_t);
200 extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t);
201 extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t);
202 extern void __fscache_uncache_page(struct fscache_cookie *, struct page *);
203 extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *);
204 extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *);
205 extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *,
206 					 gfp_t);
207 extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *,
208 					      struct inode *);
209 
210 /**
211  * fscache_register_netfs - Register a filesystem as desiring caching services
212  * @netfs: The description of the filesystem
213  *
214  * Register a filesystem as desiring caching services if they're available.
215  *
216  * See Documentation/filesystems/caching/netfs-api.txt for a complete
217  * description.
218  */
219 static inline
fscache_register_netfs(struct fscache_netfs * netfs)220 int fscache_register_netfs(struct fscache_netfs *netfs)
221 {
222 	if (fscache_available())
223 		return __fscache_register_netfs(netfs);
224 	else
225 		return 0;
226 }
227 
228 /**
229  * fscache_unregister_netfs - Indicate that a filesystem no longer desires
230  * caching services
231  * @netfs: The description of the filesystem
232  *
233  * Indicate that a filesystem no longer desires caching services for the
234  * moment.
235  *
236  * See Documentation/filesystems/caching/netfs-api.txt for a complete
237  * description.
238  */
239 static inline
fscache_unregister_netfs(struct fscache_netfs * netfs)240 void fscache_unregister_netfs(struct fscache_netfs *netfs)
241 {
242 	if (fscache_available())
243 		__fscache_unregister_netfs(netfs);
244 }
245 
246 /**
247  * fscache_lookup_cache_tag - Look up a cache tag
248  * @name: The name of the tag to search for
249  *
250  * Acquire a specific cache referral tag that can be used to select a specific
251  * cache in which to cache an index.
252  *
253  * See Documentation/filesystems/caching/netfs-api.txt for a complete
254  * description.
255  */
256 static inline
fscache_lookup_cache_tag(const char * name)257 struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name)
258 {
259 	if (fscache_available())
260 		return __fscache_lookup_cache_tag(name);
261 	else
262 		return NULL;
263 }
264 
265 /**
266  * fscache_release_cache_tag - Release a cache tag
267  * @tag: The tag to release
268  *
269  * Release a reference to a cache referral tag previously looked up.
270  *
271  * See Documentation/filesystems/caching/netfs-api.txt for a complete
272  * description.
273  */
274 static inline
fscache_release_cache_tag(struct fscache_cache_tag * tag)275 void fscache_release_cache_tag(struct fscache_cache_tag *tag)
276 {
277 	if (fscache_available())
278 		__fscache_release_cache_tag(tag);
279 }
280 
281 /**
282  * fscache_acquire_cookie - Acquire a cookie to represent a cache object
283  * @parent: The cookie that's to be the parent of this one
284  * @def: A description of the cache object, including callback operations
285  * @netfs_data: An arbitrary piece of data to be kept in the cookie to
286  * represent the cache object to the netfs
287  *
288  * This function is used to inform FS-Cache about part of an index hierarchy
289  * that can be used to locate files.  This is done by requesting a cookie for
290  * each index in the path to the file.
291  *
292  * See Documentation/filesystems/caching/netfs-api.txt for a complete
293  * description.
294  */
295 static inline
fscache_acquire_cookie(struct fscache_cookie * parent,const struct fscache_cookie_def * def,void * netfs_data)296 struct fscache_cookie *fscache_acquire_cookie(
297 	struct fscache_cookie *parent,
298 	const struct fscache_cookie_def *def,
299 	void *netfs_data)
300 {
301 	if (fscache_cookie_valid(parent))
302 		return __fscache_acquire_cookie(parent, def, netfs_data);
303 	else
304 		return NULL;
305 }
306 
307 /**
308  * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding
309  * it
310  * @cookie: The cookie being returned
311  * @retire: True if the cache object the cookie represents is to be discarded
312  *
313  * This function returns a cookie to the cache, forcibly discarding the
314  * associated cache object if retire is set to true.
315  *
316  * See Documentation/filesystems/caching/netfs-api.txt for a complete
317  * description.
318  */
319 static inline
fscache_relinquish_cookie(struct fscache_cookie * cookie,int retire)320 void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
321 {
322 	if (fscache_cookie_valid(cookie))
323 		__fscache_relinquish_cookie(cookie, retire);
324 }
325 
326 /**
327  * fscache_update_cookie - Request that a cache object be updated
328  * @cookie: The cookie representing the cache object
329  *
330  * Request an update of the index data for the cache object associated with the
331  * cookie.
332  *
333  * See Documentation/filesystems/caching/netfs-api.txt for a complete
334  * description.
335  */
336 static inline
fscache_update_cookie(struct fscache_cookie * cookie)337 void fscache_update_cookie(struct fscache_cookie *cookie)
338 {
339 	if (fscache_cookie_valid(cookie))
340 		__fscache_update_cookie(cookie);
341 }
342 
343 /**
344  * fscache_pin_cookie - Pin a data-storage cache object in its cache
345  * @cookie: The cookie representing the cache object
346  *
347  * Permit data-storage cache objects to be pinned in the cache.
348  *
349  * See Documentation/filesystems/caching/netfs-api.txt for a complete
350  * description.
351  */
352 static inline
fscache_pin_cookie(struct fscache_cookie * cookie)353 int fscache_pin_cookie(struct fscache_cookie *cookie)
354 {
355 	return -ENOBUFS;
356 }
357 
358 /**
359  * fscache_pin_cookie - Unpin a data-storage cache object in its cache
360  * @cookie: The cookie representing the cache object
361  *
362  * Permit data-storage cache objects to be unpinned from the cache.
363  *
364  * See Documentation/filesystems/caching/netfs-api.txt for a complete
365  * description.
366  */
367 static inline
fscache_unpin_cookie(struct fscache_cookie * cookie)368 void fscache_unpin_cookie(struct fscache_cookie *cookie)
369 {
370 }
371 
372 /**
373  * fscache_attr_changed - Notify cache that an object's attributes changed
374  * @cookie: The cookie representing the cache object
375  *
376  * Send a notification to the cache indicating that an object's attributes have
377  * changed.  This includes the data size.  These attributes will be obtained
378  * through the get_attr() cookie definition op.
379  *
380  * See Documentation/filesystems/caching/netfs-api.txt for a complete
381  * description.
382  */
383 static inline
fscache_attr_changed(struct fscache_cookie * cookie)384 int fscache_attr_changed(struct fscache_cookie *cookie)
385 {
386 	if (fscache_cookie_valid(cookie))
387 		return __fscache_attr_changed(cookie);
388 	else
389 		return -ENOBUFS;
390 }
391 
392 /**
393  * fscache_reserve_space - Reserve data space for a cached object
394  * @cookie: The cookie representing the cache object
395  * @i_size: The amount of space to be reserved
396  *
397  * Reserve an amount of space in the cache for the cache object attached to a
398  * cookie so that a write to that object within the space can always be
399  * honoured.
400  *
401  * See Documentation/filesystems/caching/netfs-api.txt for a complete
402  * description.
403  */
404 static inline
fscache_reserve_space(struct fscache_cookie * cookie,loff_t size)405 int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size)
406 {
407 	return -ENOBUFS;
408 }
409 
410 /**
411  * fscache_read_or_alloc_page - Read a page from the cache or allocate a block
412  * in which to store it
413  * @cookie: The cookie representing the cache object
414  * @page: The netfs page to fill if possible
415  * @end_io_func: The callback to invoke when and if the page is filled
416  * @context: An arbitrary piece of data to pass on to end_io_func()
417  * @gfp: The conditions under which memory allocation should be made
418  *
419  * Read a page from the cache, or if that's not possible make a potential
420  * one-block reservation in the cache into which the page may be stored once
421  * fetched from the server.
422  *
423  * If the page is not backed by the cache object, or if it there's some reason
424  * it can't be, -ENOBUFS will be returned and nothing more will be done for
425  * that page.
426  *
427  * Else, if that page is backed by the cache, a read will be initiated directly
428  * to the netfs's page and 0 will be returned by this function.  The
429  * end_io_func() callback will be invoked when the operation terminates on a
430  * completion or failure.  Note that the callback may be invoked before the
431  * return.
432  *
433  * Else, if the page is unbacked, -ENODATA is returned and a block may have
434  * been allocated in the cache.
435  *
436  * See Documentation/filesystems/caching/netfs-api.txt for a complete
437  * description.
438  */
439 static inline
fscache_read_or_alloc_page(struct fscache_cookie * cookie,struct page * page,fscache_rw_complete_t end_io_func,void * context,gfp_t gfp)440 int fscache_read_or_alloc_page(struct fscache_cookie *cookie,
441 			       struct page *page,
442 			       fscache_rw_complete_t end_io_func,
443 			       void *context,
444 			       gfp_t gfp)
445 {
446 	if (fscache_cookie_valid(cookie))
447 		return __fscache_read_or_alloc_page(cookie, page, end_io_func,
448 						    context, gfp);
449 	else
450 		return -ENOBUFS;
451 }
452 
453 /**
454  * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate
455  * blocks in which to store them
456  * @cookie: The cookie representing the cache object
457  * @mapping: The netfs inode mapping to which the pages will be attached
458  * @pages: A list of potential netfs pages to be filled
459  * @nr_pages: Number of pages to be read and/or allocated
460  * @end_io_func: The callback to invoke when and if each page is filled
461  * @context: An arbitrary piece of data to pass on to end_io_func()
462  * @gfp: The conditions under which memory allocation should be made
463  *
464  * Read a set of pages from the cache, or if that's not possible, attempt to
465  * make a potential one-block reservation for each page in the cache into which
466  * that page may be stored once fetched from the server.
467  *
468  * If some pages are not backed by the cache object, or if it there's some
469  * reason they can't be, -ENOBUFS will be returned and nothing more will be
470  * done for that pages.
471  *
472  * Else, if some of the pages are backed by the cache, a read will be initiated
473  * directly to the netfs's page and 0 will be returned by this function.  The
474  * end_io_func() callback will be invoked when the operation terminates on a
475  * completion or failure.  Note that the callback may be invoked before the
476  * return.
477  *
478  * Else, if a page is unbacked, -ENODATA is returned and a block may have
479  * been allocated in the cache.
480  *
481  * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in
482  * regard to different pages, the return values are prioritised in that order.
483  * Any pages submitted for reading are removed from the pages list.
484  *
485  * See Documentation/filesystems/caching/netfs-api.txt for a complete
486  * description.
487  */
488 static inline
fscache_read_or_alloc_pages(struct fscache_cookie * cookie,struct address_space * mapping,struct list_head * pages,unsigned * nr_pages,fscache_rw_complete_t end_io_func,void * context,gfp_t gfp)489 int fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
490 				struct address_space *mapping,
491 				struct list_head *pages,
492 				unsigned *nr_pages,
493 				fscache_rw_complete_t end_io_func,
494 				void *context,
495 				gfp_t gfp)
496 {
497 	if (fscache_cookie_valid(cookie))
498 		return __fscache_read_or_alloc_pages(cookie, mapping, pages,
499 						     nr_pages, end_io_func,
500 						     context, gfp);
501 	else
502 		return -ENOBUFS;
503 }
504 
505 /**
506  * fscache_alloc_page - Allocate a block in which to store a page
507  * @cookie: The cookie representing the cache object
508  * @page: The netfs page to allocate a page for
509  * @gfp: The conditions under which memory allocation should be made
510  *
511  * Request Allocation a block in the cache in which to store a netfs page
512  * without retrieving any contents from the cache.
513  *
514  * If the page is not backed by a file then -ENOBUFS will be returned and
515  * nothing more will be done, and no reservation will be made.
516  *
517  * Else, a block will be allocated if one wasn't already, and 0 will be
518  * returned
519  *
520  * See Documentation/filesystems/caching/netfs-api.txt for a complete
521  * description.
522  */
523 static inline
fscache_alloc_page(struct fscache_cookie * cookie,struct page * page,gfp_t gfp)524 int fscache_alloc_page(struct fscache_cookie *cookie,
525 		       struct page *page,
526 		       gfp_t gfp)
527 {
528 	if (fscache_cookie_valid(cookie))
529 		return __fscache_alloc_page(cookie, page, gfp);
530 	else
531 		return -ENOBUFS;
532 }
533 
534 /**
535  * fscache_write_page - Request storage of a page in the cache
536  * @cookie: The cookie representing the cache object
537  * @page: The netfs page to store
538  * @gfp: The conditions under which memory allocation should be made
539  *
540  * Request the contents of the netfs page be written into the cache.  This
541  * request may be ignored if no cache block is currently allocated, in which
542  * case it will return -ENOBUFS.
543  *
544  * If a cache block was already allocated, a write will be initiated and 0 will
545  * be returned.  The PG_fscache_write page bit is set immediately and will then
546  * be cleared at the completion of the write to indicate the success or failure
547  * of the operation.  Note that the completion may happen before the return.
548  *
549  * See Documentation/filesystems/caching/netfs-api.txt for a complete
550  * description.
551  */
552 static inline
fscache_write_page(struct fscache_cookie * cookie,struct page * page,gfp_t gfp)553 int fscache_write_page(struct fscache_cookie *cookie,
554 		       struct page *page,
555 		       gfp_t gfp)
556 {
557 	if (fscache_cookie_valid(cookie))
558 		return __fscache_write_page(cookie, page, gfp);
559 	else
560 		return -ENOBUFS;
561 }
562 
563 /**
564  * fscache_uncache_page - Indicate that caching is no longer required on a page
565  * @cookie: The cookie representing the cache object
566  * @page: The netfs page that was being cached.
567  *
568  * Tell the cache that we no longer want a page to be cached and that it should
569  * remove any knowledge of the netfs page it may have.
570  *
571  * Note that this cannot cancel any outstanding I/O operations between this
572  * page and the cache.
573  *
574  * See Documentation/filesystems/caching/netfs-api.txt for a complete
575  * description.
576  */
577 static inline
fscache_uncache_page(struct fscache_cookie * cookie,struct page * page)578 void fscache_uncache_page(struct fscache_cookie *cookie,
579 			  struct page *page)
580 {
581 	if (fscache_cookie_valid(cookie))
582 		__fscache_uncache_page(cookie, page);
583 }
584 
585 /**
586  * fscache_check_page_write - Ask if a page is being writing to the cache
587  * @cookie: The cookie representing the cache object
588  * @page: The netfs page that is being cached.
589  *
590  * Ask the cache if a page is being written to the cache.
591  *
592  * See Documentation/filesystems/caching/netfs-api.txt for a complete
593  * description.
594  */
595 static inline
fscache_check_page_write(struct fscache_cookie * cookie,struct page * page)596 bool fscache_check_page_write(struct fscache_cookie *cookie,
597 			      struct page *page)
598 {
599 	if (fscache_cookie_valid(cookie))
600 		return __fscache_check_page_write(cookie, page);
601 	return false;
602 }
603 
604 /**
605  * fscache_wait_on_page_write - Wait for a page to complete writing to the cache
606  * @cookie: The cookie representing the cache object
607  * @page: The netfs page that is being cached.
608  *
609  * Ask the cache to wake us up when a page is no longer being written to the
610  * cache.
611  *
612  * See Documentation/filesystems/caching/netfs-api.txt for a complete
613  * description.
614  */
615 static inline
fscache_wait_on_page_write(struct fscache_cookie * cookie,struct page * page)616 void fscache_wait_on_page_write(struct fscache_cookie *cookie,
617 				struct page *page)
618 {
619 	if (fscache_cookie_valid(cookie))
620 		__fscache_wait_on_page_write(cookie, page);
621 }
622 
623 /**
624  * fscache_maybe_release_page - Consider releasing a page, cancelling a store
625  * @cookie: The cookie representing the cache object
626  * @page: The netfs page that is being cached.
627  * @gfp: The gfp flags passed to releasepage()
628  *
629  * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's
630  * releasepage() call.  A storage request on the page may cancelled if it is
631  * not currently being processed.
632  *
633  * The function returns true if the page no longer has a storage request on it,
634  * and false if a storage request is left in place.  If true is returned, the
635  * page will have been passed to fscache_uncache_page().  If false is returned
636  * the page cannot be freed yet.
637  */
638 static inline
fscache_maybe_release_page(struct fscache_cookie * cookie,struct page * page,gfp_t gfp)639 bool fscache_maybe_release_page(struct fscache_cookie *cookie,
640 				struct page *page,
641 				gfp_t gfp)
642 {
643 	if (fscache_cookie_valid(cookie) && PageFsCache(page))
644 		return __fscache_maybe_release_page(cookie, page, gfp);
645 	return false;
646 }
647 
648 /**
649  * fscache_uncache_all_inode_pages - Uncache all an inode's pages
650  * @cookie: The cookie representing the inode's cache object.
651  * @inode: The inode to uncache pages from.
652  *
653  * Uncache all the pages in an inode that are marked PG_fscache, assuming them
654  * to be associated with the given cookie.
655  *
656  * This function may sleep.  It will wait for pages that are being written out
657  * and will wait whilst the PG_fscache mark is removed by the cache.
658  */
659 static inline
fscache_uncache_all_inode_pages(struct fscache_cookie * cookie,struct inode * inode)660 void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
661 				     struct inode *inode)
662 {
663 	if (fscache_cookie_valid(cookie))
664 		__fscache_uncache_all_inode_pages(cookie, inode);
665 }
666 
667 #endif /* _LINUX_FSCACHE_H */
668