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Diffstat (limited to 'ANDROID_3.4.5/include/linux/fscache.h')
| -rw-r--r-- | ANDROID_3.4.5/include/linux/fscache.h | 667 |
1 files changed, 0 insertions, 667 deletions
diff --git a/ANDROID_3.4.5/include/linux/fscache.h b/ANDROID_3.4.5/include/linux/fscache.h deleted file mode 100644 index 9ec20dec..00000000 --- a/ANDROID_3.4.5/include/linux/fscache.h +++ /dev/null @@ -1,667 +0,0 @@ -/* General filesystem caching interface - * - * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. - * Written by David Howells (dhowells@redhat.com) - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - * NOTE!!! See: - * - * Documentation/filesystems/caching/netfs-api.txt - * - * for a description of the network filesystem interface declared here. - */ - -#ifndef _LINUX_FSCACHE_H -#define _LINUX_FSCACHE_H - -#include <linux/fs.h> -#include <linux/list.h> -#include <linux/pagemap.h> -#include <linux/pagevec.h> - -#if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE) -#define fscache_available() (1) -#define fscache_cookie_valid(cookie) (cookie) -#else -#define fscache_available() (0) -#define fscache_cookie_valid(cookie) (0) -#endif - - -/* - * overload PG_private_2 to give us PG_fscache - this is used to indicate that - * a page is currently backed by a local disk cache - */ -#define PageFsCache(page) PagePrivate2((page)) -#define SetPageFsCache(page) SetPagePrivate2((page)) -#define ClearPageFsCache(page) ClearPagePrivate2((page)) -#define TestSetPageFsCache(page) TestSetPagePrivate2((page)) -#define TestClearPageFsCache(page) TestClearPagePrivate2((page)) - -/* pattern used to fill dead space in an index entry */ -#define FSCACHE_INDEX_DEADFILL_PATTERN 0x79 - -struct pagevec; -struct fscache_cache_tag; -struct fscache_cookie; -struct fscache_netfs; - -typedef void (*fscache_rw_complete_t)(struct page *page, - void *context, - int error); - -/* result of index entry consultation */ -enum fscache_checkaux { - FSCACHE_CHECKAUX_OKAY, /* entry okay as is */ - FSCACHE_CHECKAUX_NEEDS_UPDATE, /* entry requires update */ - FSCACHE_CHECKAUX_OBSOLETE, /* entry requires deletion */ -}; - -/* - * fscache cookie definition - */ -struct fscache_cookie_def { - /* name of cookie type */ - char name[16]; - - /* cookie type */ - uint8_t type; -#define FSCACHE_COOKIE_TYPE_INDEX 0 -#define FSCACHE_COOKIE_TYPE_DATAFILE 1 - - /* select the cache into which to insert an entry in this index - * - optional - * - should return a cache identifier or NULL to cause the cache to be - * inherited from the parent if possible or the first cache picked - * for a non-index file if not - */ - struct fscache_cache_tag *(*select_cache)( - const void *parent_netfs_data, - const void *cookie_netfs_data); - - /* get an index key - * - should store the key data in the buffer - * - should return the amount of data stored - * - not permitted to return an error - * - the netfs data from the cookie being used as the source is - * presented - */ - uint16_t (*get_key)(const void *cookie_netfs_data, - void *buffer, - uint16_t bufmax); - - /* get certain file attributes from the netfs data - * - this function can be absent for an index - * - not permitted to return an error - * - the netfs data from the cookie being used as the source is - * presented - */ - void (*get_attr)(const void *cookie_netfs_data, uint64_t *size); - - /* get the auxiliary data from netfs data - * - this function can be absent if the index carries no state data - * - should store the auxiliary data in the buffer - * - should return the amount of amount stored - * - not permitted to return an error - * - the netfs data from the cookie being used as the source is - * presented - */ - uint16_t (*get_aux)(const void *cookie_netfs_data, - void *buffer, - uint16_t bufmax); - - /* consult the netfs about the state of an object - * - this function can be absent if the index carries no state data - * - the netfs data from the cookie being used as the target is - * presented, as is the auxiliary data - */ - enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, - const void *data, - uint16_t datalen); - - /* get an extra reference on a read context - * - this function can be absent if the completion function doesn't - * require a context - */ - void (*get_context)(void *cookie_netfs_data, void *context); - - /* release an extra reference on a read context - * - this function can be absent if the completion function doesn't - * require a context - */ - void (*put_context)(void *cookie_netfs_data, void *context); - - /* indicate pages that now have cache metadata retained - * - this function should mark the specified pages as now being cached - * - the pages will have been marked with PG_fscache before this is - * called, so this is optional - */ - void (*mark_pages_cached)(void *cookie_netfs_data, - struct address_space *mapping, - struct pagevec *cached_pvec); - - /* indicate the cookie is no longer cached - * - this function is called when the backing store currently caching - * a cookie is removed - * - the netfs should use this to clean up any markers indicating - * cached pages - * - this is mandatory for any object that may have data - */ - void (*now_uncached)(void *cookie_netfs_data); -}; - -/* - * fscache cached network filesystem type - * - name, version and ops must be filled in before registration - * - all other fields will be set during registration - */ -struct fscache_netfs { - uint32_t version; /* indexing version */ - const char *name; /* filesystem name */ - struct fscache_cookie *primary_index; - struct list_head link; /* internal link */ -}; - -/* - * slow-path functions for when there is actually caching available, and the - * netfs does actually have a valid token - * - these are not to be called directly - * - these are undefined symbols when FS-Cache is not configured and the - * optimiser takes care of not using them - */ -extern int __fscache_register_netfs(struct fscache_netfs *); -extern void __fscache_unregister_netfs(struct fscache_netfs *); -extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); -extern void __fscache_release_cache_tag(struct fscache_cache_tag *); - -extern struct fscache_cookie *__fscache_acquire_cookie( - struct fscache_cookie *, - const struct fscache_cookie_def *, - void *); -extern void __fscache_relinquish_cookie(struct fscache_cookie *, int); -extern void __fscache_update_cookie(struct fscache_cookie *); -extern int __fscache_attr_changed(struct fscache_cookie *); -extern int __fscache_read_or_alloc_page(struct fscache_cookie *, - struct page *, - fscache_rw_complete_t, - void *, - gfp_t); -extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, - struct address_space *, - struct list_head *, - unsigned *, - fscache_rw_complete_t, - void *, - gfp_t); -extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); -extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t); -extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); -extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); -extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); -extern bool __fscache_maybe_release_page(struct fscache_cookie *, struct page *, - gfp_t); -extern void __fscache_uncache_all_inode_pages(struct fscache_cookie *, - struct inode *); - -/** - * fscache_register_netfs - Register a filesystem as desiring caching services - * @netfs: The description of the filesystem - * - * Register a filesystem as desiring caching services if they're available. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_register_netfs(struct fscache_netfs *netfs) -{ - if (fscache_available()) - return __fscache_register_netfs(netfs); - else - return 0; -} - -/** - * fscache_unregister_netfs - Indicate that a filesystem no longer desires - * caching services - * @netfs: The description of the filesystem - * - * Indicate that a filesystem no longer desires caching services for the - * moment. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_unregister_netfs(struct fscache_netfs *netfs) -{ - if (fscache_available()) - __fscache_unregister_netfs(netfs); -} - -/** - * fscache_lookup_cache_tag - Look up a cache tag - * @name: The name of the tag to search for - * - * Acquire a specific cache referral tag that can be used to select a specific - * cache in which to cache an index. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) -{ - if (fscache_available()) - return __fscache_lookup_cache_tag(name); - else - return NULL; -} - -/** - * fscache_release_cache_tag - Release a cache tag - * @tag: The tag to release - * - * Release a reference to a cache referral tag previously looked up. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_release_cache_tag(struct fscache_cache_tag *tag) -{ - if (fscache_available()) - __fscache_release_cache_tag(tag); -} - -/** - * fscache_acquire_cookie - Acquire a cookie to represent a cache object - * @parent: The cookie that's to be the parent of this one - * @def: A description of the cache object, including callback operations - * @netfs_data: An arbitrary piece of data to be kept in the cookie to - * represent the cache object to the netfs - * - * This function is used to inform FS-Cache about part of an index hierarchy - * that can be used to locate files. This is done by requesting a cookie for - * each index in the path to the file. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -struct fscache_cookie *fscache_acquire_cookie( - struct fscache_cookie *parent, - const struct fscache_cookie_def *def, - void *netfs_data) -{ - if (fscache_cookie_valid(parent)) - return __fscache_acquire_cookie(parent, def, netfs_data); - else - return NULL; -} - -/** - * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding - * it - * @cookie: The cookie being returned - * @retire: True if the cache object the cookie represents is to be discarded - * - * This function returns a cookie to the cache, forcibly discarding the - * associated cache object if retire is set to true. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) -{ - if (fscache_cookie_valid(cookie)) - __fscache_relinquish_cookie(cookie, retire); -} - -/** - * fscache_update_cookie - Request that a cache object be updated - * @cookie: The cookie representing the cache object - * - * Request an update of the index data for the cache object associated with the - * cookie. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_update_cookie(struct fscache_cookie *cookie) -{ - if (fscache_cookie_valid(cookie)) - __fscache_update_cookie(cookie); -} - -/** - * fscache_pin_cookie - Pin a data-storage cache object in its cache - * @cookie: The cookie representing the cache object - * - * Permit data-storage cache objects to be pinned in the cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_pin_cookie(struct fscache_cookie *cookie) -{ - return -ENOBUFS; -} - -/** - * fscache_pin_cookie - Unpin a data-storage cache object in its cache - * @cookie: The cookie representing the cache object - * - * Permit data-storage cache objects to be unpinned from the cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_unpin_cookie(struct fscache_cookie *cookie) -{ -} - -/** - * fscache_attr_changed - Notify cache that an object's attributes changed - * @cookie: The cookie representing the cache object - * - * Send a notification to the cache indicating that an object's attributes have - * changed. This includes the data size. These attributes will be obtained - * through the get_attr() cookie definition op. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_attr_changed(struct fscache_cookie *cookie) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_attr_changed(cookie); - else - return -ENOBUFS; -} - -/** - * fscache_reserve_space - Reserve data space for a cached object - * @cookie: The cookie representing the cache object - * @i_size: The amount of space to be reserved - * - * Reserve an amount of space in the cache for the cache object attached to a - * cookie so that a write to that object within the space can always be - * honoured. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size) -{ - return -ENOBUFS; -} - -/** - * fscache_read_or_alloc_page - Read a page from the cache or allocate a block - * in which to store it - * @cookie: The cookie representing the cache object - * @page: The netfs page to fill if possible - * @end_io_func: The callback to invoke when and if the page is filled - * @context: An arbitrary piece of data to pass on to end_io_func() - * @gfp: The conditions under which memory allocation should be made - * - * Read a page from the cache, or if that's not possible make a potential - * one-block reservation in the cache into which the page may be stored once - * fetched from the server. - * - * If the page is not backed by the cache object, or if it there's some reason - * it can't be, -ENOBUFS will be returned and nothing more will be done for - * that page. - * - * Else, if that page is backed by the cache, a read will be initiated directly - * to the netfs's page and 0 will be returned by this function. The - * end_io_func() callback will be invoked when the operation terminates on a - * completion or failure. Note that the callback may be invoked before the - * return. - * - * Else, if the page is unbacked, -ENODATA is returned and a block may have - * been allocated in the cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_read_or_alloc_page(struct fscache_cookie *cookie, - struct page *page, - fscache_rw_complete_t end_io_func, - void *context, - gfp_t gfp) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_read_or_alloc_page(cookie, page, end_io_func, - context, gfp); - else - return -ENOBUFS; -} - -/** - * fscache_read_or_alloc_pages - Read pages from the cache and/or allocate - * blocks in which to store them - * @cookie: The cookie representing the cache object - * @mapping: The netfs inode mapping to which the pages will be attached - * @pages: A list of potential netfs pages to be filled - * @nr_pages: Number of pages to be read and/or allocated - * @end_io_func: The callback to invoke when and if each page is filled - * @context: An arbitrary piece of data to pass on to end_io_func() - * @gfp: The conditions under which memory allocation should be made - * - * Read a set of pages from the cache, or if that's not possible, attempt to - * make a potential one-block reservation for each page in the cache into which - * that page may be stored once fetched from the server. - * - * If some pages are not backed by the cache object, or if it there's some - * reason they can't be, -ENOBUFS will be returned and nothing more will be - * done for that pages. - * - * Else, if some of the pages are backed by the cache, a read will be initiated - * directly to the netfs's page and 0 will be returned by this function. The - * end_io_func() callback will be invoked when the operation terminates on a - * completion or failure. Note that the callback may be invoked before the - * return. - * - * Else, if a page is unbacked, -ENODATA is returned and a block may have - * been allocated in the cache. - * - * Because the function may want to return all of -ENOBUFS, -ENODATA and 0 in - * regard to different pages, the return values are prioritised in that order. - * Any pages submitted for reading are removed from the pages list. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages, - fscache_rw_complete_t end_io_func, - void *context, - gfp_t gfp) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_read_or_alloc_pages(cookie, mapping, pages, - nr_pages, end_io_func, - context, gfp); - else - return -ENOBUFS; -} - -/** - * fscache_alloc_page - Allocate a block in which to store a page - * @cookie: The cookie representing the cache object - * @page: The netfs page to allocate a page for - * @gfp: The conditions under which memory allocation should be made - * - * Request Allocation a block in the cache in which to store a netfs page - * without retrieving any contents from the cache. - * - * If the page is not backed by a file then -ENOBUFS will be returned and - * nothing more will be done, and no reservation will be made. - * - * Else, a block will be allocated if one wasn't already, and 0 will be - * returned - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_alloc_page(struct fscache_cookie *cookie, - struct page *page, - gfp_t gfp) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_alloc_page(cookie, page, gfp); - else - return -ENOBUFS; -} - -/** - * fscache_write_page - Request storage of a page in the cache - * @cookie: The cookie representing the cache object - * @page: The netfs page to store - * @gfp: The conditions under which memory allocation should be made - * - * Request the contents of the netfs page be written into the cache. This - * request may be ignored if no cache block is currently allocated, in which - * case it will return -ENOBUFS. - * - * If a cache block was already allocated, a write will be initiated and 0 will - * be returned. The PG_fscache_write page bit is set immediately and will then - * be cleared at the completion of the write to indicate the success or failure - * of the operation. Note that the completion may happen before the return. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -int fscache_write_page(struct fscache_cookie *cookie, - struct page *page, - gfp_t gfp) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_write_page(cookie, page, gfp); - else - return -ENOBUFS; -} - -/** - * fscache_uncache_page - Indicate that caching is no longer required on a page - * @cookie: The cookie representing the cache object - * @page: The netfs page that was being cached. - * - * Tell the cache that we no longer want a page to be cached and that it should - * remove any knowledge of the netfs page it may have. - * - * Note that this cannot cancel any outstanding I/O operations between this - * page and the cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_uncache_page(struct fscache_cookie *cookie, - struct page *page) -{ - if (fscache_cookie_valid(cookie)) - __fscache_uncache_page(cookie, page); -} - -/** - * fscache_check_page_write - Ask if a page is being writing to the cache - * @cookie: The cookie representing the cache object - * @page: The netfs page that is being cached. - * - * Ask the cache if a page is being written to the cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -bool fscache_check_page_write(struct fscache_cookie *cookie, - struct page *page) -{ - if (fscache_cookie_valid(cookie)) - return __fscache_check_page_write(cookie, page); - return false; -} - -/** - * fscache_wait_on_page_write - Wait for a page to complete writing to the cache - * @cookie: The cookie representing the cache object - * @page: The netfs page that is being cached. - * - * Ask the cache to wake us up when a page is no longer being written to the - * cache. - * - * See Documentation/filesystems/caching/netfs-api.txt for a complete - * description. - */ -static inline -void fscache_wait_on_page_write(struct fscache_cookie *cookie, - struct page *page) -{ - if (fscache_cookie_valid(cookie)) - __fscache_wait_on_page_write(cookie, page); -} - -/** - * fscache_maybe_release_page - Consider releasing a page, cancelling a store - * @cookie: The cookie representing the cache object - * @page: The netfs page that is being cached. - * @gfp: The gfp flags passed to releasepage() - * - * Consider releasing a page for the vmscan algorithm, on behalf of the netfs's - * releasepage() call. A storage request on the page may cancelled if it is - * not currently being processed. - * - * The function returns true if the page no longer has a storage request on it, - * and false if a storage request is left in place. If true is returned, the - * page will have been passed to fscache_uncache_page(). If false is returned - * the page cannot be freed yet. - */ -static inline -bool fscache_maybe_release_page(struct fscache_cookie *cookie, - struct page *page, - gfp_t gfp) -{ - if (fscache_cookie_valid(cookie) && PageFsCache(page)) - return __fscache_maybe_release_page(cookie, page, gfp); - return false; -} - -/** - * fscache_uncache_all_inode_pages - Uncache all an inode's pages - * @cookie: The cookie representing the inode's cache object. - * @inode: The inode to uncache pages from. - * - * Uncache all the pages in an inode that are marked PG_fscache, assuming them - * to be associated with the given cookie. - * - * This function may sleep. It will wait for pages that are being written out - * and will wait whilst the PG_fscache mark is removed by the cache. - */ -static inline -void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, - struct inode *inode) -{ - if (fscache_cookie_valid(cookie)) - __fscache_uncache_all_inode_pages(cookie, inode); -} - -#endif /* _LINUX_FSCACHE_H */ |