| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* General filesystem caching interface |
| * |
| * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * NOTE!!! See: |
| * |
| * Documentation/filesystems/caching/netfs-api.rst |
| * |
| * 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> |
| #include <linux/list_bl.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); |
| |
| /* 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 and the object size |
| */ |
| enum fscache_checkaux (*check_aux)(void *cookie_netfs_data, |
| const void *data, |
| uint16_t datalen, |
| loff_t object_size); |
| |
| /* 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 page that now have cache metadata retained |
| * - this function should mark the specified page as now being cached |
| * - the page will have been marked with PG_fscache before this is |
| * called, so this is optional |
| */ |
| void (*mark_page_cached)(void *cookie_netfs_data, |
| struct address_space *mapping, |
| struct page *page); |
| }; |
| |
| /* |
| * 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; |
| }; |
| |
| /* |
| * data file or index object cookie |
| * - a file will only appear in one cache |
| * - a request to cache a file may or may not be honoured, subject to |
| * constraints such as disk space |
| * - indices are created on disk just-in-time |
| */ |
| struct fscache_cookie { |
| atomic_t usage; /* number of users of this cookie */ |
| atomic_t n_children; /* number of children of this cookie */ |
| atomic_t n_active; /* number of active users of netfs ptrs */ |
| spinlock_t lock; |
| spinlock_t stores_lock; /* lock on page store tree */ |
| struct hlist_head backing_objects; /* object(s) backing this file/index */ |
| const struct fscache_cookie_def *def; /* definition */ |
| struct fscache_cookie *parent; /* parent of this entry */ |
| struct hlist_bl_node hash_link; /* Link in hash table */ |
| void *netfs_data; /* back pointer to netfs */ |
| struct radix_tree_root stores; /* pages to be stored on this cookie */ |
| #define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */ |
| #define FSCACHE_COOKIE_STORING_TAG 1 /* pages tag: writing to cache */ |
| |
| unsigned long flags; |
| #define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */ |
| #define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */ |
| #define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */ |
| #define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */ |
| #define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */ |
| #define FSCACHE_COOKIE_ENABLED 5 /* T if cookie is enabled */ |
| #define FSCACHE_COOKIE_ENABLEMENT_LOCK 6 /* T if cookie is being en/disabled */ |
| #define FSCACHE_COOKIE_AUX_UPDATED 8 /* T if the auxiliary data was updated */ |
| #define FSCACHE_COOKIE_ACQUIRED 9 /* T if cookie is in use */ |
| #define FSCACHE_COOKIE_RELINQUISHING 10 /* T if cookie is being relinquished */ |
| |
| u8 type; /* Type of object */ |
| u8 key_len; /* Length of index key */ |
| u8 aux_len; /* Length of auxiliary data */ |
| u32 key_hash; /* Hash of parent, type, key, len */ |
| union { |
| void *key; /* Index key */ |
| u8 inline_key[16]; /* - If the key is short enough */ |
| }; |
| union { |
| void *aux; /* Auxiliary data */ |
| u8 inline_aux[8]; /* - If the aux data is short enough */ |
| }; |
| }; |
| |
| static inline bool fscache_cookie_enabled(struct fscache_cookie *cookie) |
| { |
| return test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); |
| } |
| |
| /* |
| * 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 *, |
| const void *, size_t, |
| const void *, size_t, |
| void *, loff_t, bool); |
| extern void __fscache_relinquish_cookie(struct fscache_cookie *, const void *, bool); |
| extern int __fscache_check_consistency(struct fscache_cookie *, const void *); |
| extern void __fscache_update_cookie(struct fscache_cookie *, const void *); |
| extern int __fscache_attr_changed(struct fscache_cookie *); |
| extern void __fscache_invalidate(struct fscache_cookie *); |
| extern void __fscache_wait_on_invalidate(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 *, loff_t, 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 *); |
| extern void __fscache_readpages_cancel(struct fscache_cookie *cookie, |
| struct list_head *pages); |
| extern void __fscache_disable_cookie(struct fscache_cookie *, const void *, bool); |
| extern void __fscache_enable_cookie(struct fscache_cookie *, const void *, loff_t, |
| bool (*)(void *), void *); |
| |
| /** |
| * 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.rst 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.rst 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.rst 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.rst 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 |
| * @index_key: The index key for this cookie |
| * @index_key_len: Size of the index key |
| * @aux_data: The auxiliary data for the cookie (may be NULL) |
| * @aux_data_len: Size of the auxiliary data buffer |
| * @netfs_data: An arbitrary piece of data to be kept in the cookie to |
| * represent the cache object to the netfs |
| * @object_size: The initial size of object |
| * @enable: Whether or not to enable a data cookie immediately |
| * |
| * 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.rst for a complete |
| * description. |
| */ |
| static inline |
| struct fscache_cookie *fscache_acquire_cookie( |
| struct fscache_cookie *parent, |
| const struct fscache_cookie_def *def, |
| const void *index_key, |
| size_t index_key_len, |
| const void *aux_data, |
| size_t aux_data_len, |
| void *netfs_data, |
| loff_t object_size, |
| bool enable) |
| { |
| if (fscache_cookie_valid(parent) && fscache_cookie_enabled(parent)) |
| return __fscache_acquire_cookie(parent, def, |
| index_key, index_key_len, |
| aux_data, aux_data_len, |
| netfs_data, object_size, enable); |
| else |
| return NULL; |
| } |
| |
| /** |
| * fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding |
| * it |
| * @cookie: The cookie being returned |
| * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
| * @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. The opportunity is |
| * provided to update the auxiliary data in the cache before the object is |
| * disconnected. |
| * |
| * See Documentation/filesystems/caching/netfs-api.rst for a complete |
| * description. |
| */ |
| static inline |
| void fscache_relinquish_cookie(struct fscache_cookie *cookie, |
| const void *aux_data, |
| bool retire) |
| { |
| if (fscache_cookie_valid(cookie)) |
| __fscache_relinquish_cookie(cookie, aux_data, retire); |
| } |
| |
| /** |
| * fscache_check_consistency - Request validation of a cache's auxiliary data |
| * @cookie: The cookie representing the cache object |
| * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
| * |
| * Request an consistency check from fscache, which passes the request to the |
| * backing cache. The auxiliary data on the cookie will be updated first if |
| * @aux_data is set. |
| * |
| * Returns 0 if consistent and -ESTALE if inconsistent. May also |
| * return -ENOMEM and -ERESTARTSYS. |
| */ |
| static inline |
| int fscache_check_consistency(struct fscache_cookie *cookie, |
| const void *aux_data) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| return __fscache_check_consistency(cookie, aux_data); |
| else |
| return 0; |
| } |
| |
| /** |
| * fscache_update_cookie - Request that a cache object be updated |
| * @cookie: The cookie representing the cache object |
| * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
| * |
| * Request an update of the index data for the cache object associated with the |
| * cookie. The auxiliary data on the cookie will be updated first if @aux_data |
| * is set. |
| * |
| * See Documentation/filesystems/caching/netfs-api.rst for a complete |
| * description. |
| */ |
| static inline |
| void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| __fscache_update_cookie(cookie, aux_data); |
| } |
| |
| /** |
| * 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.rst 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.rst 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.rst for a complete |
| * description. |
| */ |
| static inline |
| int fscache_attr_changed(struct fscache_cookie *cookie) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| return __fscache_attr_changed(cookie); |
| else |
| return -ENOBUFS; |
| } |
| |
| /** |
| * fscache_invalidate - Notify cache that an object needs invalidation |
| * @cookie: The cookie representing the cache object |
| * |
| * Notify the cache that an object is needs to be invalidated and that it |
| * should abort any retrievals or stores it is doing on the cache. The object |
| * is then marked non-caching until such time as the invalidation is complete. |
| * |
| * This can be called with spinlocks held. |
| * |
| * See Documentation/filesystems/caching/netfs-api.rst for a complete |
| * description. |
| */ |
| static inline |
| void fscache_invalidate(struct fscache_cookie *cookie) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| __fscache_invalidate(cookie); |
| } |
| |
| /** |
| * fscache_wait_on_invalidate - Wait for invalidation to complete |
| * @cookie: The cookie representing the cache object |
| * |
| * Wait for the invalidation of an object to complete. |
| * |
| * See Documentation/filesystems/caching/netfs-api.rst for a complete |
| * description. |
| */ |
| static inline |
| void fscache_wait_on_invalidate(struct fscache_cookie *cookie) |
| { |
| if (fscache_cookie_valid(cookie)) |
| __fscache_wait_on_invalidate(cookie); |
| } |
| |
| /** |
| * 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.rst 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.rst 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) && fscache_cookie_enabled(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.rst 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) && fscache_cookie_enabled(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.rst 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) && fscache_cookie_enabled(cookie)) |
| return __fscache_alloc_page(cookie, page, gfp); |
| else |
| return -ENOBUFS; |
| } |
| |
| /** |
| * fscache_readpages_cancel - Cancel read/alloc on pages |
| * @cookie: The cookie representing the inode's cache object. |
| * @pages: The netfs pages that we canceled write on in readpages() |
| * |
| * Uncache/unreserve the pages reserved earlier in readpages() via |
| * fscache_readpages_or_alloc() and similar. In most successful caches in |
| * readpages() this doesn't do anything. In cases when the underlying netfs's |
| * readahead failed we need to clean up the pagelist (unmark and uncache). |
| * |
| * This function may sleep as it may have to clean up disk state. |
| */ |
| static inline |
| void fscache_readpages_cancel(struct fscache_cookie *cookie, |
| struct list_head *pages) |
| { |
| if (fscache_cookie_valid(cookie)) |
| __fscache_readpages_cancel(cookie, pages); |
| } |
| |
| /** |
| * fscache_write_page - Request storage of a page in the cache |
| * @cookie: The cookie representing the cache object |
| * @page: The netfs page to store |
| * @object_size: Updated size of object |
| * @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.rst for a complete |
| * description. |
| */ |
| static inline |
| int fscache_write_page(struct fscache_cookie *cookie, |
| struct page *page, |
| loff_t object_size, |
| gfp_t gfp) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| return __fscache_write_page(cookie, page, object_size, 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.rst 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.rst 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.rst 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 true; |
| } |
| |
| /** |
| * 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); |
| } |
| |
| /** |
| * fscache_disable_cookie - Disable a cookie |
| * @cookie: The cookie representing the cache object |
| * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
| * @invalidate: Invalidate the backing object |
| * |
| * Disable a cookie from accepting further alloc, read, write, invalidate, |
| * update or acquire operations. Outstanding operations can still be waited |
| * upon and pages can still be uncached and the cookie relinquished. |
| * |
| * This will not return until all outstanding operations have completed. |
| * |
| * If @invalidate is set, then the backing object will be invalidated and |
| * detached, otherwise it will just be detached. |
| * |
| * If @aux_data is set, then auxiliary data will be updated from that. |
| */ |
| static inline |
| void fscache_disable_cookie(struct fscache_cookie *cookie, |
| const void *aux_data, |
| bool invalidate) |
| { |
| if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) |
| __fscache_disable_cookie(cookie, aux_data, invalidate); |
| } |
| |
| /** |
| * fscache_enable_cookie - Reenable a cookie |
| * @cookie: The cookie representing the cache object |
| * @aux_data: The updated auxiliary data for the cookie (may be NULL) |
| * @object_size: Current size of object |
| * @can_enable: A function to permit enablement once lock is held |
| * @data: Data for can_enable() |
| * |
| * Reenable a previously disabled cookie, allowing it to accept further alloc, |
| * read, write, invalidate, update or acquire operations. An attempt will be |
| * made to immediately reattach the cookie to a backing object. If @aux_data |
| * is set, the auxiliary data attached to the cookie will be updated. |
| * |
| * The can_enable() function is called (if not NULL) once the enablement lock |
| * is held to rule on whether enablement is still permitted to go ahead. |
| */ |
| static inline |
| void fscache_enable_cookie(struct fscache_cookie *cookie, |
| const void *aux_data, |
| loff_t object_size, |
| bool (*can_enable)(void *data), |
| void *data) |
| { |
| if (fscache_cookie_valid(cookie) && !fscache_cookie_enabled(cookie)) |
| __fscache_enable_cookie(cookie, aux_data, object_size, |
| can_enable, data); |
| } |
| |
| #endif /* _LINUX_FSCACHE_H */ |