--- zzzz-none-000/linux-3.10.107/include/linux/fscache.h 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/include/linux/fscache.h 2021-02-04 17:41:59.000000000 +0000 @@ -167,6 +167,42 @@ }; /* + * 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 +217,9 @@ 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 *); extern void __fscache_invalidate(struct fscache_cookie *); @@ -208,6 +245,11 @@ 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 *, bool); +extern void __fscache_enable_cookie(struct fscache_cookie *, + bool (*)(void *), void *); /** * fscache_register_netfs - Register a filesystem as desiring caching services @@ -286,6 +328,7 @@ * @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 @@ -298,10 +341,12 @@ 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; } @@ -319,13 +364,32 @@ * 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); } /** + * fscache_check_consistency - Request that if the cache is updated + * @cookie: The cookie representing the cache object + * + * Request an consistency check from fscache, which passes the request + * to the backing cache. + * + * Returns 0 if consistent and -ESTALE if inconsistent. May also + * return -ENOMEM and -ERESTARTSYS. + */ +static inline +int fscache_check_consistency(struct fscache_cookie *cookie) +{ + if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie)) + return __fscache_check_consistency(cookie); + else + return 0; +} + +/** * fscache_update_cookie - Request that a cache object be updated * @cookie: The cookie representing the cache object * @@ -338,7 +402,7 @@ 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); } @@ -385,7 +449,7 @@ 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; @@ -407,7 +471,7 @@ 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); } @@ -481,7 +545,7 @@ 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 @@ -532,7 +596,7 @@ 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); @@ -563,13 +627,33 @@ 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; } /** + * 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 @@ -592,7 +676,7 @@ 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; @@ -702,4 +786,47 @@ __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 */