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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65#define FSCACHE_CACHE_WITHDRAWN 1 /* cache has been withdrawn */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 */
100#define FSCACHE_OP_KEEP_FLAGS 0x0070 /* flags to keep when repurposing an op */
David Howells0dfc41d2009-04-03 16:42:36 +0100101
David Howells9f105232012-12-20 21:52:35 +0000102 enum fscache_operation_state state;
David Howells0dfc41d2009-04-03 16:42:36 +0100103 atomic_t usage;
104 unsigned debug_id; /* debugging ID */
105
106 /* operation processor callback
107 * - can be NULL if FSCACHE_OP_WAITING is going to be used to perform
108 * the op in a non-pool thread */
109 fscache_operation_processor_t processor;
110
111 /* operation releaser */
112 fscache_operation_release_t release;
113};
114
115extern atomic_t fscache_op_debug_id;
Tejun Heo8af7c122010-07-20 22:09:01 +0200116extern void fscache_op_work_func(struct work_struct *work);
David Howells0dfc41d2009-04-03 16:42:36 +0100117
118extern void fscache_enqueue_operation(struct fscache_operation *);
David Howells1f372df2012-12-13 20:03:13 +0000119extern void fscache_op_complete(struct fscache_operation *, bool);
David Howells0dfc41d2009-04-03 16:42:36 +0100120extern void fscache_put_operation(struct fscache_operation *);
121
122/**
123 * fscache_operation_init - Do basic initialisation of an operation
124 * @op: The operation to initialise
125 * @release: The release function to assign
126 *
127 * Do basic initialisation of an operation. The caller must still set flags,
Tejun Heo8af7c122010-07-20 22:09:01 +0200128 * object and processor if needed.
David Howells0dfc41d2009-04-03 16:42:36 +0100129 */
130static inline void fscache_operation_init(struct fscache_operation *op,
Tejun Heo8af7c122010-07-20 22:09:01 +0200131 fscache_operation_processor_t processor,
132 fscache_operation_release_t release)
David Howells0dfc41d2009-04-03 16:42:36 +0100133{
Tejun Heo8af7c122010-07-20 22:09:01 +0200134 INIT_WORK(&op->work, fscache_op_work_func);
David Howells0dfc41d2009-04-03 16:42:36 +0100135 atomic_set(&op->usage, 1);
David Howells9f105232012-12-20 21:52:35 +0000136 op->state = FSCACHE_OP_ST_INITIALISED;
David Howells0dfc41d2009-04-03 16:42:36 +0100137 op->debug_id = atomic_inc_return(&fscache_op_debug_id);
Tejun Heo8af7c122010-07-20 22:09:01 +0200138 op->processor = processor;
David Howells0dfc41d2009-04-03 16:42:36 +0100139 op->release = release;
140 INIT_LIST_HEAD(&op->pend_link);
141}
142
David Howells0dfc41d2009-04-03 16:42:36 +0100143/*
144 * data read operation
145 */
146struct fscache_retrieval {
147 struct fscache_operation op;
148 struct address_space *mapping; /* netfs pages */
149 fscache_rw_complete_t end_io_func; /* function to call on I/O completion */
150 void *context; /* netfs read context (pinned) */
151 struct list_head to_do; /* list of things to be done by the backend */
152 unsigned long start_time; /* time at which retrieval started */
David Howells9f105232012-12-20 21:52:35 +0000153 unsigned n_pages; /* number of pages to be retrieved */
David Howells0dfc41d2009-04-03 16:42:36 +0100154};
155
156typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
157 struct page *page,
158 gfp_t gfp);
159
160typedef int (*fscache_pages_retrieval_func_t)(struct fscache_retrieval *op,
161 struct list_head *pages,
162 unsigned *nr_pages,
163 gfp_t gfp);
164
165/**
166 * fscache_get_retrieval - Get an extra reference on a retrieval operation
167 * @op: The retrieval operation to get a reference on
168 *
169 * Get an extra reference on a retrieval operation.
170 */
171static inline
172struct fscache_retrieval *fscache_get_retrieval(struct fscache_retrieval *op)
173{
174 atomic_inc(&op->op.usage);
175 return op;
176}
177
178/**
179 * fscache_enqueue_retrieval - Enqueue a retrieval operation for processing
180 * @op: The retrieval operation affected
181 *
182 * Enqueue a retrieval operation for processing by the FS-Cache thread pool.
183 */
184static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
185{
186 fscache_enqueue_operation(&op->op);
187}
188
189/**
David Howells9f105232012-12-20 21:52:35 +0000190 * fscache_retrieval_complete - Record (partial) completion of a retrieval
191 * @op: The retrieval operation affected
192 * @n_pages: The number of pages to account for
193 */
194static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
195 int n_pages)
196{
197 op->n_pages -= n_pages;
198 if (op->n_pages <= 0)
David Howells1f372df2012-12-13 20:03:13 +0000199 fscache_op_complete(&op->op, true);
David Howells9f105232012-12-20 21:52:35 +0000200}
201
202/**
David Howells0dfc41d2009-04-03 16:42:36 +0100203 * fscache_put_retrieval - Drop a reference to a retrieval operation
204 * @op: The retrieval operation affected
David Howells9f105232012-12-20 21:52:35 +0000205 * @n_pages: The number of pages to account for
David Howells0dfc41d2009-04-03 16:42:36 +0100206 *
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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300254 /* store the updated auxiliary data on an object */
David Howells0dfc41d2009-04-03 16:42:36 +0100255 void (*update_object)(struct fscache_object *object);
256
David Howellsef778e72012-12-20 21:52:36 +0000257 /* Invalidate an object */
258 void (*invalidate_object)(struct fscache_operation *op);
259
David Howells0dfc41d2009-04-03 16:42:36 +0100260 /* discard the resources pinned by an object and effect retirement if
261 * necessary */
262 void (*drop_object)(struct fscache_object *object);
263
264 /* dispose of a reference to an object */
265 void (*put_object)(struct fscache_object *object);
266
267 /* sync a cache */
268 void (*sync_cache)(struct fscache_cache *cache);
269
270 /* notification that the attributes of a non-index object (such as
271 * i_size) have changed */
272 int (*attr_changed)(struct fscache_object *object);
273
274 /* reserve space for an object's data and associated metadata */
275 int (*reserve_space)(struct fscache_object *object, loff_t i_size);
276
277 /* request a backing block for a page be read or allocated in the
278 * cache */
279 fscache_page_retrieval_func_t read_or_alloc_page;
280
281 /* request backing blocks for a list of pages be read or allocated in
282 * the cache */
283 fscache_pages_retrieval_func_t read_or_alloc_pages;
284
285 /* request a backing block for a page be allocated in the cache so that
286 * it can be written directly */
287 fscache_page_retrieval_func_t allocate_page;
288
289 /* request backing blocks for pages be allocated in the cache so that
290 * they can be written directly */
291 fscache_pages_retrieval_func_t allocate_pages;
292
293 /* write a page to its backing block in the cache */
294 int (*write_page)(struct fscache_storage *op, struct page *page);
295
296 /* detach backing block from a page (optional)
297 * - must release the cookie lock before returning
298 * - may sleep
299 */
300 void (*uncache_page)(struct fscache_object *object,
301 struct page *page);
302
303 /* dissociate a cache from all the pages it was backing */
304 void (*dissociate_pages)(struct fscache_cache *cache);
305};
306
307/*
308 * data file or index object cookie
309 * - a file will only appear in one cache
310 * - a request to cache a file may or may not be honoured, subject to
311 * constraints such as disk space
312 * - indices are created on disk just-in-time
313 */
314struct fscache_cookie {
315 atomic_t usage; /* number of users of this cookie */
316 atomic_t n_children; /* number of children of this cookie */
317 spinlock_t lock;
David Howells1bccf512009-11-19 18:11:25 +0000318 spinlock_t stores_lock; /* lock on page store tree */
David Howells0dfc41d2009-04-03 16:42:36 +0100319 struct hlist_head backing_objects; /* object(s) backing this file/index */
320 const struct fscache_cookie_def *def; /* definition */
321 struct fscache_cookie *parent; /* parent of this entry */
322 void *netfs_data; /* back pointer to netfs */
323 struct radix_tree_root stores; /* pages to be stored on this cookie */
324#define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */
David Howells201a1542009-11-19 18:11:35 +0000325#define FSCACHE_COOKIE_STORING_TAG 1 /* pages tag: writing to cache */
David Howells0dfc41d2009-04-03 16:42:36 +0100326
327 unsigned long flags;
328#define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */
329#define FSCACHE_COOKIE_CREATING 1 /* T if non-index object being created still */
330#define FSCACHE_COOKIE_NO_DATA_YET 2 /* T if new object with no cached data yet */
331#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */
332#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */
333#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */
David Howellsef46ed82012-12-20 21:52:35 +0000334#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */
David Howellsef778e72012-12-20 21:52:36 +0000335#define FSCACHE_COOKIE_INVALIDATING 7 /* T if cookie is being invalidated */
David Howells0dfc41d2009-04-03 16:42:36 +0100336};
337
338extern struct fscache_cookie fscache_fsdef_index;
339
340/*
David Howells36a02de2012-12-05 13:34:46 +0000341 * Event list for fscache_object::{event_mask,events}
342 */
343enum {
344 FSCACHE_OBJECT_EV_REQUEUE, /* T if object should be requeued */
345 FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
346 FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
347 FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
348 FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
349 FSCACHE_OBJECT_EV_RELEASE, /* T if netfs requested object release */
350 FSCACHE_OBJECT_EV_RETIRE, /* T if netfs requested object retirement */
351 FSCACHE_OBJECT_EV_WITHDRAW, /* T if cache requested object withdrawal */
352 NR_FSCACHE_OBJECT_EVENTS
353};
354
355#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
356
357/*
David Howells0dfc41d2009-04-03 16:42:36 +0100358 * on-disk cache file or index handle
359 */
360struct fscache_object {
361 enum fscache_object_state {
362 FSCACHE_OBJECT_INIT, /* object in initial unbound state */
363 FSCACHE_OBJECT_LOOKING_UP, /* looking up object */
364 FSCACHE_OBJECT_CREATING, /* creating object */
365
366 /* active states */
367 FSCACHE_OBJECT_AVAILABLE, /* cleaning up object after creation */
368 FSCACHE_OBJECT_ACTIVE, /* object is usable */
David Howellsef778e72012-12-20 21:52:36 +0000369 FSCACHE_OBJECT_INVALIDATING, /* object is invalidating */
David Howells0dfc41d2009-04-03 16:42:36 +0100370 FSCACHE_OBJECT_UPDATING, /* object is updating */
371
372 /* terminal states */
373 FSCACHE_OBJECT_DYING, /* object waiting for accessors to finish */
374 FSCACHE_OBJECT_LC_DYING, /* object cleaning up after lookup/create */
375 FSCACHE_OBJECT_ABORT_INIT, /* abort the init state */
376 FSCACHE_OBJECT_RELEASING, /* releasing object */
377 FSCACHE_OBJECT_RECYCLING, /* retiring object */
378 FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */
379 FSCACHE_OBJECT_DEAD, /* object is now dead */
David Howells440f0af2009-11-19 18:11:01 +0000380 FSCACHE_OBJECT__NSTATES
David Howells0dfc41d2009-04-03 16:42:36 +0100381 } state;
382
383 int debug_id; /* debugging ID */
384 int n_children; /* number of child objects */
David Howells9f105232012-12-20 21:52:35 +0000385 int n_ops; /* number of extant ops on object */
David Howells0dfc41d2009-04-03 16:42:36 +0100386 int n_obj_ops; /* number of object ops outstanding on object */
387 int n_in_progress; /* number of ops in progress */
David Howells9f105232012-12-20 21:52:35 +0000388 int n_exclusive; /* number of exclusive ops queued or in progress */
David Howells4fbf4292009-11-19 18:11:04 +0000389 atomic_t n_reads; /* number of read ops in progress */
David Howells0dfc41d2009-04-03 16:42:36 +0100390 spinlock_t lock; /* state and operations lock */
391
392 unsigned long lookup_jif; /* time at which lookup started */
393 unsigned long event_mask; /* events this object is interested in */
394 unsigned long events; /* events to be processed by this object
395 * (order is important - using fls) */
David Howells0dfc41d2009-04-03 16:42:36 +0100396
397 unsigned long flags;
398#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
399#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
400#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
401
402 struct list_head cache_link; /* link in cache->object_list */
403 struct hlist_node cookie_link; /* link in cookie->backing_objects */
404 struct fscache_cache *cache; /* cache that supplied this object */
405 struct fscache_cookie *cookie; /* netfs's file/index object */
406 struct fscache_object *parent; /* parent object */
Tejun Heo8b8edef2010-07-20 22:09:01 +0200407 struct work_struct work; /* attention scheduling record */
David Howells0dfc41d2009-04-03 16:42:36 +0100408 struct list_head dependents; /* FIFO of dependent objects */
409 struct list_head dep_link; /* link in parent's dependents list */
410 struct list_head pending_ops; /* unstarted operations on this object */
David Howells4fbf4292009-11-19 18:11:04 +0000411#ifdef CONFIG_FSCACHE_OBJECT_LIST
412 struct rb_node objlist_link; /* link in global object list */
413#endif
David Howells0dfc41d2009-04-03 16:42:36 +0100414 pgoff_t store_limit; /* current storage limit */
David Howellsa17754f2009-11-19 18:11:52 +0000415 loff_t store_limit_l; /* current storage limit */
David Howells0dfc41d2009-04-03 16:42:36 +0100416};
417
418extern const char *fscache_object_states[];
419
420#define fscache_object_is_active(obj) \
421 (!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
422 (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \
423 (obj)->state < FSCACHE_OBJECT_DYING)
424
David Howells60d543c2009-11-19 18:11:45 +0000425#define fscache_object_is_dead(obj) \
426 (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
427 (obj)->state >= FSCACHE_OBJECT_DYING)
428
Tejun Heo8b8edef2010-07-20 22:09:01 +0200429extern void fscache_object_work_func(struct work_struct *work);
David Howells0dfc41d2009-04-03 16:42:36 +0100430
431/**
432 * fscache_object_init - Initialise a cache object description
433 * @object: Object description
434 *
435 * Initialise a cache object description to its basic values.
436 *
437 * See Documentation/filesystems/caching/backend-api.txt for a complete
438 * description.
439 */
440static inline
441void fscache_object_init(struct fscache_object *object,
442 struct fscache_cookie *cookie,
443 struct fscache_cache *cache)
444{
445 atomic_inc(&cache->object_count);
446
447 object->state = FSCACHE_OBJECT_INIT;
448 spin_lock_init(&object->lock);
449 INIT_LIST_HEAD(&object->cache_link);
450 INIT_HLIST_NODE(&object->cookie_link);
Tejun Heo8b8edef2010-07-20 22:09:01 +0200451 INIT_WORK(&object->work, fscache_object_work_func);
David Howells0dfc41d2009-04-03 16:42:36 +0100452 INIT_LIST_HEAD(&object->dependents);
453 INIT_LIST_HEAD(&object->dep_link);
454 INIT_LIST_HEAD(&object->pending_ops);
455 object->n_children = 0;
456 object->n_ops = object->n_in_progress = object->n_exclusive = 0;
457 object->events = object->event_mask = 0;
458 object->flags = 0;
459 object->store_limit = 0;
David Howellsa17754f2009-11-19 18:11:52 +0000460 object->store_limit_l = 0;
David Howells0dfc41d2009-04-03 16:42:36 +0100461 object->cache = cache;
462 object->cookie = cookie;
463 object->parent = NULL;
464}
465
466extern void fscache_object_lookup_negative(struct fscache_object *object);
467extern void fscache_obtained_object(struct fscache_object *object);
468
David Howells4fbf4292009-11-19 18:11:04 +0000469#ifdef CONFIG_FSCACHE_OBJECT_LIST
470extern void fscache_object_destroy(struct fscache_object *object);
471#else
472#define fscache_object_destroy(object) do {} while(0)
473#endif
474
David Howells0dfc41d2009-04-03 16:42:36 +0100475/**
476 * fscache_object_destroyed - Note destruction of an object in a cache
477 * @cache: The cache from which the object came
478 *
479 * Note the destruction and deallocation of an object record in a cache.
480 */
481static inline void fscache_object_destroyed(struct fscache_cache *cache)
482{
483 if (atomic_dec_and_test(&cache->object_count))
484 wake_up_all(&fscache_cache_cleared_wq);
485}
486
487/**
488 * fscache_object_lookup_error - Note an object encountered an error
489 * @object: The object on which the error was encountered
490 *
491 * Note that an object encountered a fatal error (usually an I/O error) and
492 * that it should be withdrawn as soon as possible.
493 */
494static inline void fscache_object_lookup_error(struct fscache_object *object)
495{
496 set_bit(FSCACHE_OBJECT_EV_ERROR, &object->events);
497}
498
499/**
500 * fscache_set_store_limit - Set the maximum size to be stored in an object
501 * @object: The object to set the maximum on
502 * @i_size: The limit to set in bytes
503 *
504 * Set the maximum size an object is permitted to reach, implying the highest
505 * byte that may be written. Intended to be called by the attr_changed() op.
506 *
507 * See Documentation/filesystems/caching/backend-api.txt for a complete
508 * description.
509 */
510static inline
511void fscache_set_store_limit(struct fscache_object *object, loff_t i_size)
512{
David Howellsa17754f2009-11-19 18:11:52 +0000513 object->store_limit_l = i_size;
David Howells0dfc41d2009-04-03 16:42:36 +0100514 object->store_limit = i_size >> PAGE_SHIFT;
515 if (i_size & ~PAGE_MASK)
516 object->store_limit++;
517}
518
519/**
520 * fscache_end_io - End a retrieval operation on a page
521 * @op: The FS-Cache operation covering the retrieval
522 * @page: The page that was to be fetched
523 * @error: The error code (0 if successful)
524 *
525 * Note the end of an operation to retrieve a page, as covered by a particular
526 * operation record.
527 */
528static inline void fscache_end_io(struct fscache_retrieval *op,
529 struct page *page, int error)
530{
531 op->end_io_func(page, op->context, error);
532}
533
534/*
535 * out-of-line cache backend functions
536 */
Joe Perchesb9075fa2011-10-31 17:11:33 -0700537extern __printf(3, 4)
538void fscache_init_cache(struct fscache_cache *cache,
539 const struct fscache_cache_ops *ops,
540 const char *idfmt, ...);
David Howells0dfc41d2009-04-03 16:42:36 +0100541
542extern int fscache_add_cache(struct fscache_cache *cache,
543 struct fscache_object *fsdef,
544 const char *tagname);
545extern void fscache_withdraw_cache(struct fscache_cache *cache);
546
547extern void fscache_io_error(struct fscache_cache *cache);
548
David Howellsc4d6d8d2012-12-20 21:52:32 +0000549extern void fscache_mark_page_cached(struct fscache_retrieval *op,
550 struct page *page);
551
David Howells0dfc41d2009-04-03 16:42:36 +0100552extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
553 struct pagevec *pagevec);
554
Tejun Heo8b8edef2010-07-20 22:09:01 +0200555extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
556
David Howells0dfc41d2009-04-03 16:42:36 +0100557extern enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
558 const void *data,
559 uint16_t datalen);
560
561#endif /* _LINUX_FSCACHE_CACHE_H */