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David Howells0dfc41d2009-04-03 16:42:36 +01001/* General filesystem caching backing cache 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/backend-api.txt
14 *
15 * for a description of the cache backend interface declared here.
16 */
17
18#ifndef _LINUX_FSCACHE_CACHE_H
19#define _LINUX_FSCACHE_CACHE_H
20
21#include <linux/fscache.h>
22#include <linux/sched.h>
Tejun Heo8b8edef2010-07-20 22:09:01 +020023#include <linux/workqueue.h>
David Howells0dfc41d2009-04-03 16:42:36 +010024
25#define NR_MAXCACHES BITS_PER_LONG
26
27struct fscache_cache;
28struct fscache_cache_ops;
29struct fscache_object;
30struct fscache_operation;
31
David Howells0dfc41d2009-04-03 16:42:36 +010032/*
33 * cache tag definition
34 */
35struct fscache_cache_tag {
36 struct list_head link;
37 struct fscache_cache *cache; /* cache referred to by this tag */
38 unsigned long flags;
39#define FSCACHE_TAG_RESERVED 0 /* T if tag is reserved for a cache */
40 atomic_t usage;
41 char name[0]; /* tag name */
42};
43
44/*
45 * cache definition
46 */
47struct fscache_cache {
48 const struct fscache_cache_ops *ops;
49 struct fscache_cache_tag *tag; /* tag representing this cache */
50 struct kobject *kobj; /* system representation of this cache */
51 struct list_head link; /* link in list of caches */
52 size_t max_index_size; /* maximum size of index data */
53 char identifier[36]; /* cache label */
54
55 /* node management */
56 struct work_struct op_gc; /* operation garbage collector */
57 struct list_head object_list; /* list of data/index objects */
58 struct list_head op_gc_list; /* list of ops to be deleted */
59 spinlock_t object_list_lock;
60 spinlock_t op_gc_list_lock;
61 atomic_t object_count; /* no. of live objects in this cache */
62 struct fscache_object *fsdef; /* object for the fsdef index */
63 unsigned long flags;
64#define FSCACHE_IOERROR 0 /* cache stopped on I/O error */
65#define FSCACHE_CACHE_WITHDRAWN 1 /* cache has been withdrawn */
66};
67
68extern wait_queue_head_t fscache_cache_cleared_wq;
69
70/*
71 * operation to be applied to a cache object
72 * - retrieval initiation operations are done in the context of the process
73 * that issued them, and not in an async thread pool
74 */
75typedef void (*fscache_operation_release_t)(struct fscache_operation *op);
76typedef void (*fscache_operation_processor_t)(struct fscache_operation *op);
77
David Howells9f105232012-12-20 21:52:35 +000078enum fscache_operation_state {
79 FSCACHE_OP_ST_BLANK, /* Op is not yet submitted */
80 FSCACHE_OP_ST_INITIALISED, /* Op is initialised */
81 FSCACHE_OP_ST_PENDING, /* Op is blocked from running */
82 FSCACHE_OP_ST_IN_PROGRESS, /* Op is in progress */
83 FSCACHE_OP_ST_COMPLETE, /* Op is complete */
84 FSCACHE_OP_ST_CANCELLED, /* Op has been cancelled */
85 FSCACHE_OP_ST_DEAD /* Op is now dead */
86};
87
David Howells0dfc41d2009-04-03 16:42:36 +010088struct fscache_operation {
Tejun Heo8af7c122010-07-20 22:09:01 +020089 struct work_struct work; /* record for async ops */
David Howells0dfc41d2009-04-03 16:42:36 +010090 struct list_head pend_link; /* link in object->pending_ops */
91 struct fscache_object *object; /* object to be operated upon */
92
93 unsigned long flags;
94#define FSCACHE_OP_TYPE 0x000f /* operation type */
Tejun Heo8af7c122010-07-20 22:09:01 +020095#define FSCACHE_OP_ASYNC 0x0001 /* - async op, processor may sleep for disk */
96#define FSCACHE_OP_MYTHREAD 0x0002 /* - processing is done be issuing thread, not pool */
David Howells0dfc41d2009-04-03 16:42:36 +010097#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
98#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
David Howells9f105232012-12-20 21:52:35 +000099#define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */
David Howells13627292013-05-10 19:50:26 +0100100#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */
101#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */
David Howells0dfc41d2009-04-03 16:42:36 +0100102
David Howells9f105232012-12-20 21:52:35 +0000103 enum fscache_operation_state state;
David Howells0dfc41d2009-04-03 16:42:36 +0100104 atomic_t usage;
105 unsigned debug_id; /* debugging ID */
106
107 /* operation processor callback
108 * - can be NULL if FSCACHE_OP_WAITING is going to be used to perform
109 * the op in a non-pool thread */
110 fscache_operation_processor_t processor;
111
112 /* operation releaser */
113 fscache_operation_release_t release;
114};
115
116extern atomic_t fscache_op_debug_id;
Tejun Heo8af7c122010-07-20 22:09:01 +0200117extern void fscache_op_work_func(struct work_struct *work);
David Howells0dfc41d2009-04-03 16:42:36 +0100118
119extern void fscache_enqueue_operation(struct fscache_operation *);
David Howells1f372df2012-12-13 20:03:13 +0000120extern void fscache_op_complete(struct fscache_operation *, bool);
David Howells0dfc41d2009-04-03 16:42:36 +0100121extern void fscache_put_operation(struct fscache_operation *);
122
123/**
124 * fscache_operation_init - Do basic initialisation of an operation
125 * @op: The operation to initialise
126 * @release: The release function to assign
127 *
128 * Do basic initialisation of an operation. The caller must still set flags,
Tejun Heo8af7c122010-07-20 22:09:01 +0200129 * object and processor if needed.
David Howells0dfc41d2009-04-03 16:42:36 +0100130 */
131static inline void fscache_operation_init(struct fscache_operation *op,
Tejun Heo8af7c122010-07-20 22:09:01 +0200132 fscache_operation_processor_t processor,
133 fscache_operation_release_t release)
David Howells0dfc41d2009-04-03 16:42:36 +0100134{
Tejun Heo8af7c122010-07-20 22:09:01 +0200135 INIT_WORK(&op->work, fscache_op_work_func);
David Howells0dfc41d2009-04-03 16:42:36 +0100136 atomic_set(&op->usage, 1);
David Howells9f105232012-12-20 21:52:35 +0000137 op->state = FSCACHE_OP_ST_INITIALISED;
David Howells0dfc41d2009-04-03 16:42:36 +0100138 op->debug_id = atomic_inc_return(&fscache_op_debug_id);
Tejun Heo8af7c122010-07-20 22:09:01 +0200139 op->processor = processor;
David Howells0dfc41d2009-04-03 16:42:36 +0100140 op->release = release;
141 INIT_LIST_HEAD(&op->pend_link);
142}
143
David Howells0dfc41d2009-04-03 16:42:36 +0100144/*
145 * data read operation
146 */
147struct fscache_retrieval {
148 struct fscache_operation op;
149 struct address_space *mapping; /* netfs pages */
150 fscache_rw_complete_t end_io_func; /* function to call on I/O completion */
151 void *context; /* netfs read context (pinned) */
152 struct list_head to_do; /* list of things to be done by the backend */
153 unsigned long start_time; /* time at which retrieval started */
David Howells1bb4b7f92013-05-21 13:44:15 +0100154 atomic_t n_pages; /* number of pages to be retrieved */
David Howells0dfc41d2009-04-03 16:42:36 +0100155};
156
157typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
158 struct page *page,
159 gfp_t gfp);
160
161typedef int (*fscache_pages_retrieval_func_t)(struct fscache_retrieval *op,
162 struct list_head *pages,
163 unsigned *nr_pages,
164 gfp_t gfp);
165
166/**
167 * fscache_get_retrieval - Get an extra reference on a retrieval operation
168 * @op: The retrieval operation to get a reference on
169 *
170 * Get an extra reference on a retrieval operation.
171 */
172static inline
173struct fscache_retrieval *fscache_get_retrieval(struct fscache_retrieval *op)
174{
175 atomic_inc(&op->op.usage);
176 return op;
177}
178
179/**
180 * fscache_enqueue_retrieval - Enqueue a retrieval operation for processing
181 * @op: The retrieval operation affected
182 *
183 * Enqueue a retrieval operation for processing by the FS-Cache thread pool.
184 */
185static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
186{
187 fscache_enqueue_operation(&op->op);
188}
189
190/**
David Howells9f105232012-12-20 21:52:35 +0000191 * fscache_retrieval_complete - Record (partial) completion of a retrieval
192 * @op: The retrieval operation affected
193 * @n_pages: The number of pages to account for
194 */
195static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
196 int n_pages)
197{
David Howells1bb4b7f92013-05-21 13:44:15 +0100198 atomic_sub(n_pages, &op->n_pages);
199 if (atomic_read(&op->n_pages) <= 0)
David Howells1f372df2012-12-13 20:03:13 +0000200 fscache_op_complete(&op->op, true);
David Howells9f105232012-12-20 21:52:35 +0000201}
202
203/**
David Howells0dfc41d2009-04-03 16:42:36 +0100204 * fscache_put_retrieval - Drop a reference to a retrieval operation
205 * @op: The retrieval operation affected
206 *
207 * Drop a reference to a retrieval operation.
208 */
209static inline void fscache_put_retrieval(struct fscache_retrieval *op)
210{
211 fscache_put_operation(&op->op);
212}
213
214/*
215 * cached page storage work item
216 * - used to do three things:
217 * - batch writes to the cache
218 * - do cache writes asynchronously
219 * - defer writes until cache object lookup completion
220 */
221struct fscache_storage {
222 struct fscache_operation op;
223 pgoff_t store_limit; /* don't write more than this */
224};
225
226/*
227 * cache operations
228 */
229struct fscache_cache_ops {
230 /* name of cache provider */
231 const char *name;
232
233 /* allocate an object record for a cookie */
234 struct fscache_object *(*alloc_object)(struct fscache_cache *cache,
235 struct fscache_cookie *cookie);
236
David Howellsfee096d2009-11-19 18:12:05 +0000237 /* look up the object for a cookie
238 * - return -ETIMEDOUT to be requeued
239 */
240 int (*lookup_object)(struct fscache_object *object);
David Howells0dfc41d2009-04-03 16:42:36 +0100241
242 /* finished looking up */
243 void (*lookup_complete)(struct fscache_object *object);
244
245 /* increment the usage count on this object (may fail if unmounting) */
246 struct fscache_object *(*grab_object)(struct fscache_object *object);
247
248 /* pin an object in the cache */
249 int (*pin_object)(struct fscache_object *object);
250
251 /* unpin an object in the cache */
252 void (*unpin_object)(struct fscache_object *object);
253
David Howellsda9803b2013-08-21 17:29:38 -0400254 /* check the consistency between the backing cache and the FS-Cache
255 * cookie */
256 bool (*check_consistency)(struct fscache_operation *op);
257
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300258 /* store the updated auxiliary data on an object */
David Howells0dfc41d2009-04-03 16:42:36 +0100259 void (*update_object)(struct fscache_object *object);
260
David Howellsef778e72012-12-20 21:52:36 +0000261 /* Invalidate an object */
262 void (*invalidate_object)(struct fscache_operation *op);
263
David Howells0dfc41d2009-04-03 16:42:36 +0100264 /* discard the resources pinned by an object and effect retirement if
265 * necessary */
266 void (*drop_object)(struct fscache_object *object);
267
268 /* dispose of a reference to an object */
269 void (*put_object)(struct fscache_object *object);
270
271 /* sync a cache */
272 void (*sync_cache)(struct fscache_cache *cache);
273
274 /* notification that the attributes of a non-index object (such as
275 * i_size) have changed */
276 int (*attr_changed)(struct fscache_object *object);
277
278 /* reserve space for an object's data and associated metadata */
279 int (*reserve_space)(struct fscache_object *object, loff_t i_size);
280
281 /* request a backing block for a page be read or allocated in the
282 * cache */
283 fscache_page_retrieval_func_t read_or_alloc_page;
284
285 /* request backing blocks for a list of pages be read or allocated in
286 * the cache */
287 fscache_pages_retrieval_func_t read_or_alloc_pages;
288
289 /* request a backing block for a page be allocated in the cache so that
290 * it can be written directly */
291 fscache_page_retrieval_func_t allocate_page;
292
293 /* request backing blocks for pages be allocated in the cache so that
294 * they can be written directly */
295 fscache_pages_retrieval_func_t allocate_pages;
296
297 /* write a page to its backing block in the cache */
298 int (*write_page)(struct fscache_storage *op, struct page *page);
299
300 /* detach backing block from a page (optional)
301 * - must release the cookie lock before returning
302 * - may sleep
303 */
304 void (*uncache_page)(struct fscache_object *object,
305 struct page *page);
306
307 /* dissociate a cache from all the pages it was backing */
308 void (*dissociate_pages)(struct fscache_cache *cache);
309};
310
David Howells0dfc41d2009-04-03 16:42:36 +0100311extern struct fscache_cookie fscache_fsdef_index;
312
313/*
David Howells36a02de2012-12-05 13:34:46 +0000314 * Event list for fscache_object::{event_mask,events}
315 */
316enum {
David Howellscaaef692013-05-10 19:50:26 +0100317 FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */
318 FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */
David Howells36a02de2012-12-05 13:34:46 +0000319 FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
320 FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
321 FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
322 FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
David Howellscaaef692013-05-10 19:50:26 +0100323 FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */
David Howells36a02de2012-12-05 13:34:46 +0000324 NR_FSCACHE_OBJECT_EVENTS
325};
326
327#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
328
329/*
David Howellscaaef692013-05-10 19:50:26 +0100330 * States for object state machine.
331 */
332struct fscache_transition {
333 unsigned long events;
334 const struct fscache_state *transit_to;
335};
336
337struct fscache_state {
338 char name[24];
339 char short_name[8];
340 const struct fscache_state *(*work)(struct fscache_object *object,
341 int event);
342 const struct fscache_transition transitions[];
343};
344
345/*
David Howells0dfc41d2009-04-03 16:42:36 +0100346 * on-disk cache file or index handle
347 */
348struct fscache_object {
David Howellscaaef692013-05-10 19:50:26 +0100349 const struct fscache_state *state; /* Object state machine state */
350 const struct fscache_transition *oob_table; /* OOB state transition table */
David Howells0dfc41d2009-04-03 16:42:36 +0100351 int debug_id; /* debugging ID */
352 int n_children; /* number of child objects */
David Howells9f105232012-12-20 21:52:35 +0000353 int n_ops; /* number of extant ops on object */
David Howells0dfc41d2009-04-03 16:42:36 +0100354 int n_obj_ops; /* number of object ops outstanding on object */
355 int n_in_progress; /* number of ops in progress */
David Howells9f105232012-12-20 21:52:35 +0000356 int n_exclusive; /* number of exclusive ops queued or in progress */
David Howells4fbf4292009-11-19 18:11:04 +0000357 atomic_t n_reads; /* number of read ops in progress */
David Howells0dfc41d2009-04-03 16:42:36 +0100358 spinlock_t lock; /* state and operations lock */
359
360 unsigned long lookup_jif; /* time at which lookup started */
David Howellscaaef692013-05-10 19:50:26 +0100361 unsigned long oob_event_mask; /* OOB events this object is interested in */
David Howells0dfc41d2009-04-03 16:42:36 +0100362 unsigned long event_mask; /* events this object is interested in */
363 unsigned long events; /* events to be processed by this object
364 * (order is important - using fls) */
David Howells0dfc41d2009-04-03 16:42:36 +0100365
366 unsigned long flags;
367#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
368#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
369#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
David Howells13627292013-05-10 19:50:26 +0100370#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */
371#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */
372#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */
David Howells94d30ae2013-09-21 00:09:31 +0100373#define FSCACHE_OBJECT_RETIRED 6 /* T if object was retired on relinquishment */
David Howells0dfc41d2009-04-03 16:42:36 +0100374
375 struct list_head cache_link; /* link in cache->object_list */
376 struct hlist_node cookie_link; /* link in cookie->backing_objects */
377 struct fscache_cache *cache; /* cache that supplied this object */
378 struct fscache_cookie *cookie; /* netfs's file/index object */
379 struct fscache_object *parent; /* parent object */
Tejun Heo8b8edef2010-07-20 22:09:01 +0200380 struct work_struct work; /* attention scheduling record */
David Howells0dfc41d2009-04-03 16:42:36 +0100381 struct list_head dependents; /* FIFO of dependent objects */
382 struct list_head dep_link; /* link in parent's dependents list */
383 struct list_head pending_ops; /* unstarted operations on this object */
David Howells4fbf4292009-11-19 18:11:04 +0000384#ifdef CONFIG_FSCACHE_OBJECT_LIST
385 struct rb_node objlist_link; /* link in global object list */
386#endif
David Howells0dfc41d2009-04-03 16:42:36 +0100387 pgoff_t store_limit; /* current storage limit */
David Howellsa17754f2009-11-19 18:11:52 +0000388 loff_t store_limit_l; /* current storage limit */
David Howells0dfc41d2009-04-03 16:42:36 +0100389};
390
David Howells610be242013-05-10 19:50:25 +0100391extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
392 struct fscache_cache *);
David Howells13627292013-05-10 19:50:26 +0100393extern void fscache_object_destroy(struct fscache_object *);
David Howells0dfc41d2009-04-03 16:42:36 +0100394
395extern void fscache_object_lookup_negative(struct fscache_object *object);
396extern void fscache_obtained_object(struct fscache_object *object);
397
David Howells493f7bc2013-05-10 19:50:26 +0100398static inline bool fscache_object_is_live(struct fscache_object *object)
399{
David Howellscaaef692013-05-10 19:50:26 +0100400 return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
David Howells493f7bc2013-05-10 19:50:26 +0100401}
402
403static inline bool fscache_object_is_dying(struct fscache_object *object)
404{
405 return !fscache_object_is_live(object);
406}
407
408static inline bool fscache_object_is_available(struct fscache_object *object)
409{
David Howellscaaef692013-05-10 19:50:26 +0100410 return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
David Howells493f7bc2013-05-10 19:50:26 +0100411}
412
413static inline bool fscache_object_is_active(struct fscache_object *object)
414{
415 return fscache_object_is_available(object) &&
416 fscache_object_is_live(object) &&
417 !test_bit(FSCACHE_IOERROR, &object->cache->flags);
418}
419
420static inline bool fscache_object_is_dead(struct fscache_object *object)
421{
422 return fscache_object_is_dying(object) &&
423 test_bit(FSCACHE_IOERROR, &object->cache->flags);
424}
425
David Howells0dfc41d2009-04-03 16:42:36 +0100426/**
427 * fscache_object_destroyed - Note destruction of an object in a cache
428 * @cache: The cache from which the object came
429 *
430 * Note the destruction and deallocation of an object record in a cache.
431 */
432static inline void fscache_object_destroyed(struct fscache_cache *cache)
433{
434 if (atomic_dec_and_test(&cache->object_count))
435 wake_up_all(&fscache_cache_cleared_wq);
436}
437
438/**
439 * fscache_object_lookup_error - Note an object encountered an error
440 * @object: The object on which the error was encountered
441 *
442 * Note that an object encountered a fatal error (usually an I/O error) and
443 * that it should be withdrawn as soon as possible.
444 */
445static inline void fscache_object_lookup_error(struct fscache_object *object)
446{
447 set_bit(FSCACHE_OBJECT_EV_ERROR, &object->events);
448}
449
450/**
451 * fscache_set_store_limit - Set the maximum size to be stored in an object
452 * @object: The object to set the maximum on
453 * @i_size: The limit to set in bytes
454 *
455 * Set the maximum size an object is permitted to reach, implying the highest
456 * byte that may be written. Intended to be called by the attr_changed() op.
457 *
458 * See Documentation/filesystems/caching/backend-api.txt for a complete
459 * description.
460 */
461static inline
462void fscache_set_store_limit(struct fscache_object *object, loff_t i_size)
463{
David Howellsa17754f2009-11-19 18:11:52 +0000464 object->store_limit_l = i_size;
David Howells0dfc41d2009-04-03 16:42:36 +0100465 object->store_limit = i_size >> PAGE_SHIFT;
466 if (i_size & ~PAGE_MASK)
467 object->store_limit++;
468}
469
470/**
471 * fscache_end_io - End a retrieval operation on a page
472 * @op: The FS-Cache operation covering the retrieval
473 * @page: The page that was to be fetched
474 * @error: The error code (0 if successful)
475 *
476 * Note the end of an operation to retrieve a page, as covered by a particular
477 * operation record.
478 */
479static inline void fscache_end_io(struct fscache_retrieval *op,
480 struct page *page, int error)
481{
482 op->end_io_func(page, op->context, error);
483}
484
David Howells8fb883f2013-09-21 00:09:31 +0100485static inline void __fscache_use_cookie(struct fscache_cookie *cookie)
486{
487 atomic_inc(&cookie->n_active);
488}
489
David Howells13627292013-05-10 19:50:26 +0100490/**
491 * fscache_use_cookie - Request usage of cookie attached to an object
492 * @object: Object description
493 *
494 * Request usage of the cookie attached to an object. NULL is returned if the
495 * relinquishment had reduced the cookie usage count to 0.
496 */
497static inline bool fscache_use_cookie(struct fscache_object *object)
498{
499 struct fscache_cookie *cookie = object->cookie;
500 return atomic_inc_not_zero(&cookie->n_active) != 0;
501}
502
David Howells8fb883f2013-09-21 00:09:31 +0100503static inline bool __fscache_unuse_cookie(struct fscache_cookie *cookie)
504{
505 return atomic_dec_and_test(&cookie->n_active);
506}
507
508static inline void __fscache_wake_unused_cookie(struct fscache_cookie *cookie)
509{
510 wake_up_atomic_t(&cookie->n_active);
511}
512
David Howells13627292013-05-10 19:50:26 +0100513/**
514 * fscache_unuse_cookie - Cease usage of cookie attached to an object
515 * @object: Object description
516 *
517 * Cease usage of the cookie attached to an object. When the users count
518 * reaches zero then the cookie relinquishment will be permitted to proceed.
519 */
520static inline void fscache_unuse_cookie(struct fscache_object *object)
521{
522 struct fscache_cookie *cookie = object->cookie;
David Howells8fb883f2013-09-21 00:09:31 +0100523 if (__fscache_unuse_cookie(cookie))
524 __fscache_wake_unused_cookie(cookie);
David Howells13627292013-05-10 19:50:26 +0100525}
526
David Howells0dfc41d2009-04-03 16:42:36 +0100527/*
528 * out-of-line cache backend functions
529 */
Joe Perchesb9075fa2011-10-31 17:11:33 -0700530extern __printf(3, 4)
531void fscache_init_cache(struct fscache_cache *cache,
532 const struct fscache_cache_ops *ops,
533 const char *idfmt, ...);
David Howells0dfc41d2009-04-03 16:42:36 +0100534
535extern int fscache_add_cache(struct fscache_cache *cache,
536 struct fscache_object *fsdef,
537 const char *tagname);
538extern void fscache_withdraw_cache(struct fscache_cache *cache);
539
540extern void fscache_io_error(struct fscache_cache *cache);
541
David Howellsc4d6d8d2012-12-20 21:52:32 +0000542extern void fscache_mark_page_cached(struct fscache_retrieval *op,
543 struct page *page);
544
David Howells0dfc41d2009-04-03 16:42:36 +0100545extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
546 struct pagevec *pagevec);
547
Tejun Heo8b8edef2010-07-20 22:09:01 +0200548extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
549
David Howells0dfc41d2009-04-03 16:42:36 +0100550extern enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
551 const void *data,
552 uint16_t datalen);
553
554#endif /* _LINUX_FSCACHE_CACHE_H */