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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65#define FSCACHE_CACHE_WITHDRAWN 1 /* cache has been withdrawn */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);
David Howellsd3b97ca2015-02-24 10:05:29 +000077typedef void (*fscache_operation_cancel_t)(struct fscache_operation *op);
David Howells0dfc41d2009-04-03 16:42:36 +010078
David Howells9f105232012-12-20 21:52:35 +000079enum fscache_operation_state {
80 FSCACHE_OP_ST_BLANK, /* Op is not yet submitted */
81 FSCACHE_OP_ST_INITIALISED, /* Op is initialised */
82 FSCACHE_OP_ST_PENDING, /* Op is blocked from running */
83 FSCACHE_OP_ST_IN_PROGRESS, /* Op is in progress */
84 FSCACHE_OP_ST_COMPLETE, /* Op is complete */
85 FSCACHE_OP_ST_CANCELLED, /* Op has been cancelled */
86 FSCACHE_OP_ST_DEAD /* Op is now dead */
87};
88
David Howells0dfc41d2009-04-03 16:42:36 +010089struct fscache_operation {
Tejun Heo8af7c122010-07-20 22:09:01 +020090 struct work_struct work; /* record for async ops */
David Howells0dfc41d2009-04-03 16:42:36 +010091 struct list_head pend_link; /* link in object->pending_ops */
92 struct fscache_object *object; /* object to be operated upon */
93
94 unsigned long flags;
95#define FSCACHE_OP_TYPE 0x000f /* operation type */
Tejun Heo8af7c122010-07-20 22:09:01 +020096#define FSCACHE_OP_ASYNC 0x0001 /* - async op, processor may sleep for disk */
97#define FSCACHE_OP_MYTHREAD 0x0002 /* - processing is done be issuing thread, not pool */
David Howells0dfc41d2009-04-03 16:42:36 +010098#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
99#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
David Howells9f105232012-12-20 21:52:35 +0000100#define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */
David Howells13627292013-05-10 19:50:26 +0100101#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */
102#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */
David Howells0dfc41d2009-04-03 16:42:36 +0100103
David Howells9f105232012-12-20 21:52:35 +0000104 enum fscache_operation_state state;
David Howells0dfc41d2009-04-03 16:42:36 +0100105 atomic_t usage;
106 unsigned debug_id; /* debugging ID */
107
108 /* operation processor callback
109 * - can be NULL if FSCACHE_OP_WAITING is going to be used to perform
110 * the op in a non-pool thread */
111 fscache_operation_processor_t processor;
112
David Howellsd3b97ca2015-02-24 10:05:29 +0000113 /* Operation cancellation cleanup (optional) */
114 fscache_operation_cancel_t cancel;
115
David Howells0dfc41d2009-04-03 16:42:36 +0100116 /* operation releaser */
117 fscache_operation_release_t release;
118};
119
120extern atomic_t fscache_op_debug_id;
Tejun Heo8af7c122010-07-20 22:09:01 +0200121extern void fscache_op_work_func(struct work_struct *work);
David Howells0dfc41d2009-04-03 16:42:36 +0100122
123extern void fscache_enqueue_operation(struct fscache_operation *);
David Howells1f372df2012-12-13 20:03:13 +0000124extern void fscache_op_complete(struct fscache_operation *, bool);
David Howells0dfc41d2009-04-03 16:42:36 +0100125extern void fscache_put_operation(struct fscache_operation *);
David Howells1339ec92015-02-25 13:26:39 +0000126extern void fscache_operation_init(struct fscache_operation *,
127 fscache_operation_processor_t,
David Howellsd3b97ca2015-02-24 10:05:29 +0000128 fscache_operation_cancel_t,
David Howells1339ec92015-02-25 13:26:39 +0000129 fscache_operation_release_t);
David Howells0dfc41d2009-04-03 16:42:36 +0100130
David Howells0dfc41d2009-04-03 16:42:36 +0100131/*
132 * data read operation
133 */
134struct fscache_retrieval {
135 struct fscache_operation op;
David Howells4a471322015-02-24 10:05:29 +0000136 struct fscache_cookie *cookie; /* The netfs cookie */
David Howells0dfc41d2009-04-03 16:42:36 +0100137 struct address_space *mapping; /* netfs pages */
138 fscache_rw_complete_t end_io_func; /* function to call on I/O completion */
139 void *context; /* netfs read context (pinned) */
140 struct list_head to_do; /* list of things to be done by the backend */
141 unsigned long start_time; /* time at which retrieval started */
David Howells1bb4b7f92013-05-21 13:44:15 +0100142 atomic_t n_pages; /* number of pages to be retrieved */
David Howells0dfc41d2009-04-03 16:42:36 +0100143};
144
145typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
146 struct page *page,
147 gfp_t gfp);
148
149typedef int (*fscache_pages_retrieval_func_t)(struct fscache_retrieval *op,
150 struct list_head *pages,
151 unsigned *nr_pages,
152 gfp_t gfp);
153
154/**
155 * fscache_get_retrieval - Get an extra reference on a retrieval operation
156 * @op: The retrieval operation to get a reference on
157 *
158 * Get an extra reference on a retrieval operation.
159 */
160static inline
161struct fscache_retrieval *fscache_get_retrieval(struct fscache_retrieval *op)
162{
163 atomic_inc(&op->op.usage);
164 return op;
165}
166
167/**
168 * fscache_enqueue_retrieval - Enqueue a retrieval operation for processing
169 * @op: The retrieval operation affected
170 *
171 * Enqueue a retrieval operation for processing by the FS-Cache thread pool.
172 */
173static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
174{
175 fscache_enqueue_operation(&op->op);
176}
177
178/**
David Howells9f105232012-12-20 21:52:35 +0000179 * fscache_retrieval_complete - Record (partial) completion of a retrieval
180 * @op: The retrieval operation affected
181 * @n_pages: The number of pages to account for
182 */
183static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
184 int n_pages)
185{
David Howells1bb4b7f92013-05-21 13:44:15 +0100186 atomic_sub(n_pages, &op->n_pages);
187 if (atomic_read(&op->n_pages) <= 0)
David Howells1f372df2012-12-13 20:03:13 +0000188 fscache_op_complete(&op->op, true);
David Howells9f105232012-12-20 21:52:35 +0000189}
190
191/**
David Howells0dfc41d2009-04-03 16:42:36 +0100192 * fscache_put_retrieval - Drop a reference to a retrieval operation
193 * @op: The retrieval operation affected
194 *
195 * Drop a reference to a retrieval operation.
196 */
197static inline void fscache_put_retrieval(struct fscache_retrieval *op)
198{
199 fscache_put_operation(&op->op);
200}
201
202/*
203 * cached page storage work item
204 * - used to do three things:
205 * - batch writes to the cache
206 * - do cache writes asynchronously
207 * - defer writes until cache object lookup completion
208 */
209struct fscache_storage {
210 struct fscache_operation op;
211 pgoff_t store_limit; /* don't write more than this */
212};
213
214/*
215 * cache operations
216 */
217struct fscache_cache_ops {
218 /* name of cache provider */
219 const char *name;
220
221 /* allocate an object record for a cookie */
222 struct fscache_object *(*alloc_object)(struct fscache_cache *cache,
223 struct fscache_cookie *cookie);
224
David Howellsfee096d2009-11-19 18:12:05 +0000225 /* look up the object for a cookie
226 * - return -ETIMEDOUT to be requeued
227 */
228 int (*lookup_object)(struct fscache_object *object);
David Howells0dfc41d2009-04-03 16:42:36 +0100229
230 /* finished looking up */
231 void (*lookup_complete)(struct fscache_object *object);
232
233 /* increment the usage count on this object (may fail if unmounting) */
234 struct fscache_object *(*grab_object)(struct fscache_object *object);
235
236 /* pin an object in the cache */
237 int (*pin_object)(struct fscache_object *object);
238
239 /* unpin an object in the cache */
240 void (*unpin_object)(struct fscache_object *object);
241
David Howellsda9803b2013-08-21 17:29:38 -0400242 /* check the consistency between the backing cache and the FS-Cache
243 * cookie */
Yan, Zheng480ce082016-05-20 18:32:31 +0800244 int (*check_consistency)(struct fscache_operation *op);
David Howellsda9803b2013-08-21 17:29:38 -0400245
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300246 /* store the updated auxiliary data on an object */
David Howells0dfc41d2009-04-03 16:42:36 +0100247 void (*update_object)(struct fscache_object *object);
248
David Howellsef778e72012-12-20 21:52:36 +0000249 /* Invalidate an object */
250 void (*invalidate_object)(struct fscache_operation *op);
251
David Howells0dfc41d2009-04-03 16:42:36 +0100252 /* discard the resources pinned by an object and effect retirement if
253 * necessary */
254 void (*drop_object)(struct fscache_object *object);
255
256 /* dispose of a reference to an object */
257 void (*put_object)(struct fscache_object *object);
258
259 /* sync a cache */
260 void (*sync_cache)(struct fscache_cache *cache);
261
262 /* notification that the attributes of a non-index object (such as
263 * i_size) have changed */
264 int (*attr_changed)(struct fscache_object *object);
265
266 /* reserve space for an object's data and associated metadata */
267 int (*reserve_space)(struct fscache_object *object, loff_t i_size);
268
269 /* request a backing block for a page be read or allocated in the
270 * cache */
271 fscache_page_retrieval_func_t read_or_alloc_page;
272
273 /* request backing blocks for a list of pages be read or allocated in
274 * the cache */
275 fscache_pages_retrieval_func_t read_or_alloc_pages;
276
277 /* request a backing block for a page be allocated in the cache so that
278 * it can be written directly */
279 fscache_page_retrieval_func_t allocate_page;
280
281 /* request backing blocks for pages be allocated in the cache so that
282 * they can be written directly */
283 fscache_pages_retrieval_func_t allocate_pages;
284
285 /* write a page to its backing block in the cache */
286 int (*write_page)(struct fscache_storage *op, struct page *page);
287
288 /* detach backing block from a page (optional)
289 * - must release the cookie lock before returning
290 * - may sleep
291 */
292 void (*uncache_page)(struct fscache_object *object,
293 struct page *page);
294
295 /* dissociate a cache from all the pages it was backing */
296 void (*dissociate_pages)(struct fscache_cache *cache);
297};
298
David Howells0dfc41d2009-04-03 16:42:36 +0100299extern struct fscache_cookie fscache_fsdef_index;
300
301/*
David Howells36a02de2012-12-05 13:34:46 +0000302 * Event list for fscache_object::{event_mask,events}
303 */
304enum {
David Howellscaaef692013-05-10 19:50:26 +0100305 FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */
306 FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */
David Howells36a02de2012-12-05 13:34:46 +0000307 FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
308 FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
309 FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
310 FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
David Howellscaaef692013-05-10 19:50:26 +0100311 FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */
David Howells36a02de2012-12-05 13:34:46 +0000312 NR_FSCACHE_OBJECT_EVENTS
313};
314
315#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
316
317/*
David Howellscaaef692013-05-10 19:50:26 +0100318 * States for object state machine.
319 */
320struct fscache_transition {
321 unsigned long events;
322 const struct fscache_state *transit_to;
323};
324
325struct fscache_state {
326 char name[24];
327 char short_name[8];
328 const struct fscache_state *(*work)(struct fscache_object *object,
329 int event);
330 const struct fscache_transition transitions[];
331};
332
333/*
David Howells0dfc41d2009-04-03 16:42:36 +0100334 * on-disk cache file or index handle
335 */
336struct fscache_object {
David Howellscaaef692013-05-10 19:50:26 +0100337 const struct fscache_state *state; /* Object state machine state */
338 const struct fscache_transition *oob_table; /* OOB state transition table */
David Howells0dfc41d2009-04-03 16:42:36 +0100339 int debug_id; /* debugging ID */
340 int n_children; /* number of child objects */
David Howells9f105232012-12-20 21:52:35 +0000341 int n_ops; /* number of extant ops on object */
David Howells0dfc41d2009-04-03 16:42:36 +0100342 int n_obj_ops; /* number of object ops outstanding on object */
343 int n_in_progress; /* number of ops in progress */
David Howells9f105232012-12-20 21:52:35 +0000344 int n_exclusive; /* number of exclusive ops queued or in progress */
David Howells4fbf4292009-11-19 18:11:04 +0000345 atomic_t n_reads; /* number of read ops in progress */
David Howells0dfc41d2009-04-03 16:42:36 +0100346 spinlock_t lock; /* state and operations lock */
347
348 unsigned long lookup_jif; /* time at which lookup started */
David Howellscaaef692013-05-10 19:50:26 +0100349 unsigned long oob_event_mask; /* OOB events this object is interested in */
David Howells0dfc41d2009-04-03 16:42:36 +0100350 unsigned long event_mask; /* events this object is interested in */
351 unsigned long events; /* events to be processed by this object
352 * (order is important - using fls) */
David Howells0dfc41d2009-04-03 16:42:36 +0100353
354 unsigned long flags;
355#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
356#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
357#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
David Howells13627292013-05-10 19:50:26 +0100358#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */
359#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */
360#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */
David Howells94d30ae2013-09-21 00:09:31 +0100361#define FSCACHE_OBJECT_RETIRED 6 /* T if object was retired on relinquishment */
David Howells182d9192015-02-19 23:47:31 +0000362#define FSCACHE_OBJECT_KILLED_BY_CACHE 7 /* T if object was killed by the cache */
David Howells0dfc41d2009-04-03 16:42:36 +0100363
364 struct list_head cache_link; /* link in cache->object_list */
365 struct hlist_node cookie_link; /* link in cookie->backing_objects */
366 struct fscache_cache *cache; /* cache that supplied this object */
367 struct fscache_cookie *cookie; /* netfs's file/index object */
368 struct fscache_object *parent; /* parent object */
Tejun Heo8b8edef2010-07-20 22:09:01 +0200369 struct work_struct work; /* attention scheduling record */
David Howells0dfc41d2009-04-03 16:42:36 +0100370 struct list_head dependents; /* FIFO of dependent objects */
371 struct list_head dep_link; /* link in parent's dependents list */
372 struct list_head pending_ops; /* unstarted operations on this object */
David Howells4fbf4292009-11-19 18:11:04 +0000373#ifdef CONFIG_FSCACHE_OBJECT_LIST
374 struct rb_node objlist_link; /* link in global object list */
375#endif
David Howells0dfc41d2009-04-03 16:42:36 +0100376 pgoff_t store_limit; /* current storage limit */
David Howellsa17754f2009-11-19 18:11:52 +0000377 loff_t store_limit_l; /* current storage limit */
David Howells0dfc41d2009-04-03 16:42:36 +0100378};
379
David Howells610be242013-05-10 19:50:25 +0100380extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
381 struct fscache_cache *);
David Howells13627292013-05-10 19:50:26 +0100382extern void fscache_object_destroy(struct fscache_object *);
David Howells0dfc41d2009-04-03 16:42:36 +0100383
384extern void fscache_object_lookup_negative(struct fscache_object *object);
385extern void fscache_obtained_object(struct fscache_object *object);
386
David Howells493f7bc2013-05-10 19:50:26 +0100387static inline bool fscache_object_is_live(struct fscache_object *object)
388{
David Howellscaaef692013-05-10 19:50:26 +0100389 return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
David Howells493f7bc2013-05-10 19:50:26 +0100390}
391
392static inline bool fscache_object_is_dying(struct fscache_object *object)
393{
394 return !fscache_object_is_live(object);
395}
396
397static inline bool fscache_object_is_available(struct fscache_object *object)
398{
David Howellscaaef692013-05-10 19:50:26 +0100399 return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
David Howells493f7bc2013-05-10 19:50:26 +0100400}
401
David Howells30ceec62015-02-24 10:05:27 +0000402static inline bool fscache_cache_is_broken(struct fscache_object *object)
403{
404 return test_bit(FSCACHE_IOERROR, &object->cache->flags);
405}
406
David Howells493f7bc2013-05-10 19:50:26 +0100407static inline bool fscache_object_is_active(struct fscache_object *object)
408{
409 return fscache_object_is_available(object) &&
410 fscache_object_is_live(object) &&
David Howells30ceec62015-02-24 10:05:27 +0000411 !fscache_cache_is_broken(object);
David Howells493f7bc2013-05-10 19:50:26 +0100412}
413
David Howells0dfc41d2009-04-03 16:42:36 +0100414/**
415 * fscache_object_destroyed - Note destruction of an object in a cache
416 * @cache: The cache from which the object came
417 *
418 * Note the destruction and deallocation of an object record in a cache.
419 */
420static inline void fscache_object_destroyed(struct fscache_cache *cache)
421{
422 if (atomic_dec_and_test(&cache->object_count))
423 wake_up_all(&fscache_cache_cleared_wq);
424}
425
426/**
427 * fscache_object_lookup_error - Note an object encountered an error
428 * @object: The object on which the error was encountered
429 *
430 * Note that an object encountered a fatal error (usually an I/O error) and
431 * that it should be withdrawn as soon as possible.
432 */
433static inline void fscache_object_lookup_error(struct fscache_object *object)
434{
435 set_bit(FSCACHE_OBJECT_EV_ERROR, &object->events);
436}
437
438/**
439 * fscache_set_store_limit - Set the maximum size to be stored in an object
440 * @object: The object to set the maximum on
441 * @i_size: The limit to set in bytes
442 *
443 * Set the maximum size an object is permitted to reach, implying the highest
444 * byte that may be written. Intended to be called by the attr_changed() op.
445 *
446 * See Documentation/filesystems/caching/backend-api.txt for a complete
447 * description.
448 */
449static inline
450void fscache_set_store_limit(struct fscache_object *object, loff_t i_size)
451{
David Howellsa17754f2009-11-19 18:11:52 +0000452 object->store_limit_l = i_size;
David Howells0dfc41d2009-04-03 16:42:36 +0100453 object->store_limit = i_size >> PAGE_SHIFT;
454 if (i_size & ~PAGE_MASK)
455 object->store_limit++;
456}
457
458/**
459 * fscache_end_io - End a retrieval operation on a page
460 * @op: The FS-Cache operation covering the retrieval
461 * @page: The page that was to be fetched
462 * @error: The error code (0 if successful)
463 *
464 * Note the end of an operation to retrieve a page, as covered by a particular
465 * operation record.
466 */
467static inline void fscache_end_io(struct fscache_retrieval *op,
468 struct page *page, int error)
469{
470 op->end_io_func(page, op->context, error);
471}
472
David Howells8fb883f2013-09-21 00:09:31 +0100473static inline void __fscache_use_cookie(struct fscache_cookie *cookie)
474{
475 atomic_inc(&cookie->n_active);
476}
477
David Howells13627292013-05-10 19:50:26 +0100478/**
479 * fscache_use_cookie - Request usage of cookie attached to an object
480 * @object: Object description
481 *
482 * Request usage of the cookie attached to an object. NULL is returned if the
483 * relinquishment had reduced the cookie usage count to 0.
484 */
485static inline bool fscache_use_cookie(struct fscache_object *object)
486{
487 struct fscache_cookie *cookie = object->cookie;
488 return atomic_inc_not_zero(&cookie->n_active) != 0;
489}
490
David Howells8fb883f2013-09-21 00:09:31 +0100491static inline bool __fscache_unuse_cookie(struct fscache_cookie *cookie)
492{
493 return atomic_dec_and_test(&cookie->n_active);
494}
495
496static inline void __fscache_wake_unused_cookie(struct fscache_cookie *cookie)
497{
498 wake_up_atomic_t(&cookie->n_active);
499}
500
David Howells13627292013-05-10 19:50:26 +0100501/**
502 * fscache_unuse_cookie - Cease usage of cookie attached to an object
503 * @object: Object description
504 *
505 * Cease usage of the cookie attached to an object. When the users count
506 * reaches zero then the cookie relinquishment will be permitted to proceed.
507 */
508static inline void fscache_unuse_cookie(struct fscache_object *object)
509{
510 struct fscache_cookie *cookie = object->cookie;
David Howells8fb883f2013-09-21 00:09:31 +0100511 if (__fscache_unuse_cookie(cookie))
512 __fscache_wake_unused_cookie(cookie);
David Howells13627292013-05-10 19:50:26 +0100513}
514
David Howells0dfc41d2009-04-03 16:42:36 +0100515/*
516 * out-of-line cache backend functions
517 */
Joe Perchesb9075fa2011-10-31 17:11:33 -0700518extern __printf(3, 4)
519void fscache_init_cache(struct fscache_cache *cache,
520 const struct fscache_cache_ops *ops,
521 const char *idfmt, ...);
David Howells0dfc41d2009-04-03 16:42:36 +0100522
523extern int fscache_add_cache(struct fscache_cache *cache,
524 struct fscache_object *fsdef,
525 const char *tagname);
526extern void fscache_withdraw_cache(struct fscache_cache *cache);
527
528extern void fscache_io_error(struct fscache_cache *cache);
529
David Howellsc4d6d8d2012-12-20 21:52:32 +0000530extern void fscache_mark_page_cached(struct fscache_retrieval *op,
531 struct page *page);
532
David Howells0dfc41d2009-04-03 16:42:36 +0100533extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
534 struct pagevec *pagevec);
535
Tejun Heo8b8edef2010-07-20 22:09:01 +0200536extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
537
David Howells0dfc41d2009-04-03 16:42:36 +0100538extern enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
539 const void *data,
540 uint16_t datalen);
541
David Howells182d9192015-02-19 23:47:31 +0000542extern void fscache_object_retrying_stale(struct fscache_object *object);
543
544enum fscache_why_object_killed {
545 FSCACHE_OBJECT_IS_STALE,
546 FSCACHE_OBJECT_NO_SPACE,
547 FSCACHE_OBJECT_WAS_RETIRED,
548 FSCACHE_OBJECT_WAS_CULLED,
549};
550extern void fscache_object_mark_killed(struct fscache_object *object,
551 enum fscache_why_object_killed why);
552
David Howells0dfc41d2009-04-03 16:42:36 +0100553#endif /* _LINUX_FSCACHE_CACHE_H */