include/linux/fscache.h

   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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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 */