diff options
Diffstat (limited to 'include/linux/fscache.h')
| -rw-r--r-- | include/linux/fscache.h | 113 |
1 files changed, 99 insertions, 14 deletions
diff --git a/include/linux/fscache.h b/include/linux/fscache.h index 19b46458e4e..115bb81912c 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -167,6 +167,42 @@ struct fscache_netfs { }; /* + * 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 */ + 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 */ +}; + +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 @@ -181,8 +217,8 @@ 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); + void *, bool); +extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool); extern int __fscache_check_consistency(struct fscache_cookie *); extern void __fscache_update_cookie(struct fscache_cookie *); extern int __fscache_attr_changed(struct fscache_cookie *); @@ -211,6 +247,9 @@ 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 *, bool); +extern void __fscache_enable_cookie(struct fscache_cookie *, + bool (*)(void *), void *); /** * fscache_register_netfs - Register a filesystem as desiring caching services @@ -289,6 +328,7 @@ void fscache_release_cache_tag(struct fscache_cache_tag *tag) * @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 + * @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 @@ -301,10 +341,12 @@ static inline struct fscache_cookie *fscache_acquire_cookie( struct fscache_cookie *parent, const struct fscache_cookie_def *def, - void *netfs_data) + void *netfs_data, + bool enable) { - if (fscache_cookie_valid(parent)) - return __fscache_acquire_cookie(parent, def, netfs_data); + if (fscache_cookie_valid(parent) && fscache_cookie_enabled(parent)) + return __fscache_acquire_cookie(parent, def, netfs_data, + enable); else return NULL; } @@ -322,7 +364,7 @@ struct fscache_cookie *fscache_acquire_cookie( * description. */ static inline -void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) +void fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire) { if (fscache_cookie_valid(cookie)) __fscache_relinquish_cookie(cookie, retire); @@ -341,7 +383,7 @@ void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) static inline int fscache_check_consistency(struct fscache_cookie *cookie) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) return __fscache_check_consistency(cookie); else return 0; @@ -360,7 +402,7 @@ int fscache_check_consistency(struct fscache_cookie *cookie) static inline void fscache_update_cookie(struct fscache_cookie *cookie) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) __fscache_update_cookie(cookie); } @@ -407,7 +449,7 @@ void fscache_unpin_cookie(struct fscache_cookie *cookie) static inline int fscache_attr_changed(struct fscache_cookie *cookie) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) return __fscache_attr_changed(cookie); else return -ENOBUFS; @@ -429,7 +471,7 @@ int fscache_attr_changed(struct fscache_cookie *cookie) static inline void fscache_invalidate(struct fscache_cookie *cookie) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) __fscache_invalidate(cookie); } @@ -503,7 +545,7 @@ int fscache_read_or_alloc_page(struct fscache_cookie *cookie, void *context, gfp_t gfp) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) return __fscache_read_or_alloc_page(cookie, page, end_io_func, context, gfp); else @@ -554,7 +596,7 @@ int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, void *context, gfp_t gfp) { - if (fscache_cookie_valid(cookie)) + 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); @@ -585,7 +627,7 @@ int fscache_alloc_page(struct fscache_cookie *cookie, struct page *page, gfp_t gfp) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) return __fscache_alloc_page(cookie, page, gfp); else return -ENOBUFS; @@ -634,7 +676,7 @@ int fscache_write_page(struct fscache_cookie *cookie, struct page *page, gfp_t gfp) { - if (fscache_cookie_valid(cookie)) + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) return __fscache_write_page(cookie, page, gfp); else return -ENOBUFS; @@ -744,4 +786,47 @@ void fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, __fscache_uncache_all_inode_pages(cookie, inode); } +/** + * fscache_disable_cookie - Disable a cookie + * @cookie: The cookie representing the cache object + * @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. + */ +static inline +void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate) +{ + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) + __fscache_disable_cookie(cookie, invalidate); +} + +/** + * fscache_enable_cookie - Reenable a cookie + * @cookie: The cookie representing the cache 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. + * + * 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, + bool (*can_enable)(void *data), + void *data) +{ + if (fscache_cookie_valid(cookie) && !fscache_cookie_enabled(cookie)) + __fscache_enable_cookie(cookie, can_enable, data); +} + #endif /* _LINUX_FSCACHE_H */ |