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- /* SPDX-License-Identifier: GPL-2.0-or-later */
- /* General filesystem caching interface
- *
- * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells ([email protected])
- *
- * 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/netfs.h>
- #include <linux/writeback.h>
- #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
- #define __fscache_available (1)
- #define fscache_available() (1)
- #define fscache_volume_valid(volume) (volume)
- #define fscache_cookie_valid(cookie) (cookie)
- #define fscache_resources_valid(cres) ((cres)->cache_priv)
- #define fscache_cookie_enabled(cookie) (cookie && !test_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
- #else
- #define __fscache_available (0)
- #define fscache_available() (0)
- #define fscache_volume_valid(volume) (0)
- #define fscache_cookie_valid(cookie) (0)
- #define fscache_resources_valid(cres) (false)
- #define fscache_cookie_enabled(cookie) (0)
- #endif
- struct fscache_cookie;
- #define FSCACHE_ADV_SINGLE_CHUNK 0x01 /* The object is a single chunk of data */
- #define FSCACHE_ADV_WRITE_CACHE 0x00 /* Do cache if written to locally */
- #define FSCACHE_ADV_WRITE_NOCACHE 0x02 /* Don't cache if written to locally */
- #define FSCACHE_ADV_WANT_CACHE_SIZE 0x04 /* Retrieve cache size at runtime */
- #define FSCACHE_INVAL_DIO_WRITE 0x01 /* Invalidate due to DIO write */
- enum fscache_want_state {
- FSCACHE_WANT_PARAMS,
- FSCACHE_WANT_WRITE,
- FSCACHE_WANT_READ,
- };
- /*
- * Data object state.
- */
- enum fscache_cookie_state {
- FSCACHE_COOKIE_STATE_QUIESCENT, /* The cookie is uncached */
- FSCACHE_COOKIE_STATE_LOOKING_UP, /* The cache object is being looked up */
- FSCACHE_COOKIE_STATE_CREATING, /* The cache object is being created */
- FSCACHE_COOKIE_STATE_ACTIVE, /* The cache is active, readable and writable */
- FSCACHE_COOKIE_STATE_INVALIDATING, /* The cache is being invalidated */
- FSCACHE_COOKIE_STATE_FAILED, /* The cache failed, withdraw to clear */
- FSCACHE_COOKIE_STATE_LRU_DISCARDING, /* The cookie is being discarded by the LRU */
- FSCACHE_COOKIE_STATE_WITHDRAWING, /* The cookie is being withdrawn */
- FSCACHE_COOKIE_STATE_RELINQUISHING, /* The cookie is being relinquished */
- FSCACHE_COOKIE_STATE_DROPPED, /* The cookie has been dropped */
- #define FSCACHE_COOKIE_STATE__NR (FSCACHE_COOKIE_STATE_DROPPED + 1)
- } __attribute__((mode(byte)));
- /*
- * Volume representation cookie.
- */
- struct fscache_volume {
- refcount_t ref;
- atomic_t n_cookies; /* Number of data cookies in volume */
- atomic_t n_accesses; /* Number of cache accesses in progress */
- unsigned int debug_id;
- unsigned int key_hash; /* Hash of key string */
- u8 *key; /* Volume ID, eg. "[email protected]@1234" */
- struct list_head proc_link; /* Link in /proc/fs/fscache/volumes */
- struct hlist_bl_node hash_link; /* Link in hash table */
- struct work_struct work;
- struct fscache_cache *cache; /* The cache in which this resides */
- void *cache_priv; /* Cache private data */
- spinlock_t lock;
- unsigned long flags;
- #define FSCACHE_VOLUME_RELINQUISHED 0 /* Volume is being cleaned up */
- #define FSCACHE_VOLUME_INVALIDATE 1 /* Volume was invalidated */
- #define FSCACHE_VOLUME_COLLIDED_WITH 2 /* Volume was collided with */
- #define FSCACHE_VOLUME_ACQUIRE_PENDING 3 /* Volume is waiting to complete acquisition */
- #define FSCACHE_VOLUME_CREATING 4 /* Volume is being created on disk */
- u8 coherency_len; /* Length of the coherency data */
- u8 coherency[]; /* Coherency data */
- };
- /*
- * Data file representation 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 {
- refcount_t ref;
- atomic_t n_active; /* number of active users of cookie */
- atomic_t n_accesses; /* Number of cache accesses in progress */
- unsigned int debug_id;
- unsigned int inval_counter; /* Number of invalidations made */
- spinlock_t lock;
- struct fscache_volume *volume; /* Parent volume of this file. */
- void *cache_priv; /* Cache-side representation */
- struct hlist_bl_node hash_link; /* Link in hash table */
- struct list_head proc_link; /* Link in proc list */
- struct list_head commit_link; /* Link in commit queue */
- struct work_struct work; /* Commit/relinq/withdraw work */
- loff_t object_size; /* Size of the netfs object */
- unsigned long unused_at; /* Time at which unused (jiffies) */
- unsigned long flags;
- #define FSCACHE_COOKIE_RELINQUISHED 0 /* T if cookie has been relinquished */
- #define FSCACHE_COOKIE_RETIRED 1 /* T if this cookie has retired on relinq */
- #define FSCACHE_COOKIE_IS_CACHING 2 /* T if this cookie is cached */
- #define FSCACHE_COOKIE_NO_DATA_TO_READ 3 /* T if this cookie has nothing to read */
- #define FSCACHE_COOKIE_NEEDS_UPDATE 4 /* T if attrs have been updated */
- #define FSCACHE_COOKIE_HAS_BEEN_CACHED 5 /* T if cookie needs withdraw-on-relinq */
- #define FSCACHE_COOKIE_DISABLED 6 /* T if cookie has been disabled */
- #define FSCACHE_COOKIE_LOCAL_WRITE 7 /* T if cookie has been modified locally */
- #define FSCACHE_COOKIE_NO_ACCESS_WAKE 8 /* T if no wake when n_accesses goes 0 */
- #define FSCACHE_COOKIE_DO_RELINQUISH 9 /* T if this cookie needs relinquishment */
- #define FSCACHE_COOKIE_DO_WITHDRAW 10 /* T if this cookie needs withdrawing */
- #define FSCACHE_COOKIE_DO_LRU_DISCARD 11 /* T if this cookie needs LRU discard */
- #define FSCACHE_COOKIE_DO_PREP_TO_WRITE 12 /* T if cookie needs write preparation */
- #define FSCACHE_COOKIE_HAVE_DATA 13 /* T if this cookie has data stored */
- #define FSCACHE_COOKIE_IS_HASHED 14 /* T if this cookie is hashed */
- #define FSCACHE_COOKIE_DO_INVALIDATE 15 /* T if cookie needs invalidation */
- enum fscache_cookie_state state;
- u8 advice; /* FSCACHE_ADV_* */
- u8 key_len; /* Length of index key */
- u8 aux_len; /* Length of auxiliary data */
- u32 key_hash; /* Hash of volume, 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 */
- };
- };
- /*
- * 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 struct fscache_volume *__fscache_acquire_volume(const char *, const char *,
- const void *, size_t);
- extern void __fscache_relinquish_volume(struct fscache_volume *, const void *, bool);
- extern struct fscache_cookie *__fscache_acquire_cookie(
- struct fscache_volume *,
- u8,
- const void *, size_t,
- const void *, size_t,
- loff_t);
- extern void __fscache_use_cookie(struct fscache_cookie *, bool);
- extern void __fscache_unuse_cookie(struct fscache_cookie *, const void *, const loff_t *);
- extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool);
- extern void __fscache_resize_cookie(struct fscache_cookie *, loff_t);
- extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t, unsigned int);
- extern int __fscache_begin_read_operation(struct netfs_cache_resources *, struct fscache_cookie *);
- extern int __fscache_begin_write_operation(struct netfs_cache_resources *, struct fscache_cookie *);
- extern void __fscache_write_to_cache(struct fscache_cookie *, struct address_space *,
- loff_t, size_t, loff_t, netfs_io_terminated_t, void *,
- bool);
- extern void __fscache_clear_page_bits(struct address_space *, loff_t, size_t);
- /**
- * fscache_acquire_volume - Register a volume as desiring caching services
- * @volume_key: An identification string for the volume
- * @cache_name: The name of the cache to use (or NULL for the default)
- * @coherency_data: Piece of arbitrary coherency data to check (or NULL)
- * @coherency_len: The size of the coherency data
- *
- * Register a volume as desiring caching services if they're available. The
- * caller must provide an identifier for the volume and may also indicate which
- * cache it should be in. If a preexisting volume entry is found in the cache,
- * the coherency data must match otherwise the entry will be invalidated.
- *
- * Returns a cookie pointer on success, -ENOMEM if out of memory or -EBUSY if a
- * cache volume of that name is already acquired. Note that "NULL" is a valid
- * cookie pointer and can be returned if caching is refused.
- */
- static inline
- struct fscache_volume *fscache_acquire_volume(const char *volume_key,
- const char *cache_name,
- const void *coherency_data,
- size_t coherency_len)
- {
- if (!fscache_available())
- return NULL;
- return __fscache_acquire_volume(volume_key, cache_name,
- coherency_data, coherency_len);
- }
- /**
- * fscache_relinquish_volume - Cease caching a volume
- * @volume: The volume cookie
- * @coherency_data: Piece of arbitrary coherency data to set (or NULL)
- * @invalidate: True if the volume should be invalidated
- *
- * Indicate that a filesystem no longer desires caching services for a volume.
- * The caller must have relinquished all file cookies prior to calling this.
- * The stored coherency data is updated.
- */
- static inline
- void fscache_relinquish_volume(struct fscache_volume *volume,
- const void *coherency_data,
- bool invalidate)
- {
- if (fscache_volume_valid(volume))
- __fscache_relinquish_volume(volume, coherency_data, invalidate);
- }
- /**
- * fscache_acquire_cookie - Acquire a cookie to represent a cache object
- * @volume: The volume in which to locate/create this cookie
- * @advice: Advice flags (FSCACHE_COOKIE_ADV_*)
- * @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
- * @object_size: The initial size of object
- *
- * Acquire a cookie to represent a data file within the given cache volume.
- *
- * See Documentation/filesystems/caching/netfs-api.rst for a complete
- * description.
- */
- static inline
- struct fscache_cookie *fscache_acquire_cookie(struct fscache_volume *volume,
- u8 advice,
- const void *index_key,
- size_t index_key_len,
- const void *aux_data,
- size_t aux_data_len,
- loff_t object_size)
- {
- if (!fscache_volume_valid(volume))
- return NULL;
- return __fscache_acquire_cookie(volume, advice,
- index_key, index_key_len,
- aux_data, aux_data_len,
- object_size);
- }
- /**
- * fscache_use_cookie - Request usage of cookie attached to an object
- * @cookie: The cookie representing the cache object
- * @will_modify: If cache is expected to be modified locally
- *
- * Request usage of the cookie attached to an object. The caller should tell
- * the cache if the object's contents are about to be modified locally and then
- * the cache can apply the policy that has been set to handle this case.
- */
- static inline void fscache_use_cookie(struct fscache_cookie *cookie,
- bool will_modify)
- {
- if (fscache_cookie_valid(cookie))
- __fscache_use_cookie(cookie, will_modify);
- }
- /**
- * fscache_unuse_cookie - Cease usage of cookie attached to an object
- * @cookie: The cookie representing the cache object
- * @aux_data: Updated auxiliary data (or NULL)
- * @object_size: Revised size of the object (or NULL)
- *
- * Cease usage of the cookie attached to an object. When the users count
- * reaches zero then the cookie relinquishment will be permitted to proceed.
- */
- static inline void fscache_unuse_cookie(struct fscache_cookie *cookie,
- const void *aux_data,
- const loff_t *object_size)
- {
- if (fscache_cookie_valid(cookie))
- __fscache_unuse_cookie(cookie, aux_data, object_size);
- }
- /**
- * 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.rst for a complete
- * description.
- */
- static inline
- void fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
- {
- if (fscache_cookie_valid(cookie))
- __fscache_relinquish_cookie(cookie, retire);
- }
- /*
- * Find the auxiliary data on a cookie.
- */
- static inline void *fscache_get_aux(struct fscache_cookie *cookie)
- {
- if (cookie->aux_len <= sizeof(cookie->inline_aux))
- return cookie->inline_aux;
- else
- return cookie->aux;
- }
- /*
- * Update the auxiliary data on a cookie.
- */
- static inline
- void fscache_update_aux(struct fscache_cookie *cookie,
- const void *aux_data, const loff_t *object_size)
- {
- void *p = fscache_get_aux(cookie);
- if (aux_data && p)
- memcpy(p, aux_data, cookie->aux_len);
- if (object_size)
- cookie->object_size = *object_size;
- }
- #ifdef CONFIG_FSCACHE_STATS
- extern atomic_t fscache_n_updates;
- #endif
- static inline
- void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
- const loff_t *object_size)
- {
- #ifdef CONFIG_FSCACHE_STATS
- atomic_inc(&fscache_n_updates);
- #endif
- fscache_update_aux(cookie, aux_data, object_size);
- smp_wmb();
- set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
- }
- /**
- * 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)
- * @object_size: The current size of the object (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 and the object size will be updated and the object possibly trimmed
- * if @object_size 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,
- const loff_t *object_size)
- {
- if (fscache_cookie_enabled(cookie))
- __fscache_update_cookie(cookie, aux_data, object_size);
- }
- /**
- * fscache_resize_cookie - Request that a cache object be resized
- * @cookie: The cookie representing the cache object
- * @new_size: The new size of the object (may be NULL)
- *
- * Request that the size of an object be changed.
- *
- * See Documentation/filesystems/caching/netfs-api.rst for a complete
- * description.
- */
- static inline
- void fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size)
- {
- if (fscache_cookie_enabled(cookie))
- __fscache_resize_cookie(cookie, new_size);
- }
- /**
- * fscache_invalidate - Notify cache that an object needs invalidation
- * @cookie: The cookie representing the cache object
- * @aux_data: The updated auxiliary data for the cookie (may be NULL)
- * @size: The revised size of the object.
- * @flags: Invalidation flags (FSCACHE_INVAL_*)
- *
- * 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. This
- * increments inval_counter on the cookie which can be used by the caller to
- * reconsider I/O requests as they complete.
- *
- * If @flags has FSCACHE_INVAL_DIO_WRITE set, this indicates that this is due
- * to a direct I/O write and will cause caching to be disabled on this cookie
- * until it is completely unused.
- *
- * See Documentation/filesystems/caching/netfs-api.rst for a complete
- * description.
- */
- static inline
- void fscache_invalidate(struct fscache_cookie *cookie,
- const void *aux_data, loff_t size, unsigned int flags)
- {
- if (fscache_cookie_enabled(cookie))
- __fscache_invalidate(cookie, aux_data, size, flags);
- }
- /**
- * fscache_operation_valid - Return true if operations resources are usable
- * @cres: The resources to check.
- *
- * Returns a pointer to the operations table if usable or NULL if not.
- */
- static inline
- const struct netfs_cache_ops *fscache_operation_valid(const struct netfs_cache_resources *cres)
- {
- return fscache_resources_valid(cres) ? cres->ops : NULL;
- }
- /**
- * fscache_begin_read_operation - Begin a read operation for the netfs lib
- * @cres: The cache resources for the read being performed
- * @cookie: The cookie representing the cache object
- *
- * Begin a read operation on behalf of the netfs helper library. @cres
- * indicates the cache resources to which the operation state should be
- * attached; @cookie indicates the cache object that will be accessed.
- *
- * This is intended to be called from the ->begin_cache_operation() netfs lib
- * operation as implemented by the network filesystem.
- *
- * @cres->inval_counter is set from @cookie->inval_counter for comparison at
- * the end of the operation. This allows invalidation during the operation to
- * be detected by the caller.
- *
- * Returns:
- * * 0 - Success
- * * -ENOBUFS - No caching available
- * * Other error code from the cache, such as -ENOMEM.
- */
- static inline
- int fscache_begin_read_operation(struct netfs_cache_resources *cres,
- struct fscache_cookie *cookie)
- {
- if (fscache_cookie_enabled(cookie))
- return __fscache_begin_read_operation(cres, cookie);
- return -ENOBUFS;
- }
- /**
- * fscache_end_operation - End the read operation for the netfs lib
- * @cres: The cache resources for the read operation
- *
- * Clean up the resources at the end of the read request.
- */
- static inline void fscache_end_operation(struct netfs_cache_resources *cres)
- {
- const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
- if (ops)
- ops->end_operation(cres);
- }
- /**
- * fscache_read - Start a read from the cache.
- * @cres: The cache resources to use
- * @start_pos: The beginning file offset in the cache file
- * @iter: The buffer to fill - and also the length
- * @read_hole: How to handle a hole in the data.
- * @term_func: The function to call upon completion
- * @term_func_priv: The private data for @term_func
- *
- * Start a read from the cache. @cres indicates the cache object to read from
- * and must be obtained by a call to fscache_begin_operation() beforehand.
- *
- * The data is read into the iterator, @iter, and that also indicates the size
- * of the operation. @start_pos is the start position in the file, though if
- * @seek_data is set appropriately, the cache can use SEEK_DATA to find the
- * next piece of data, writing zeros for the hole into the iterator.
- *
- * Upon termination of the operation, @term_func will be called and supplied
- * with @term_func_priv plus the amount of data written, if successful, or the
- * error code otherwise.
- *
- * @read_hole indicates how a partially populated region in the cache should be
- * handled. It can be one of a number of settings:
- *
- * NETFS_READ_HOLE_IGNORE - Just try to read (may return a short read).
- *
- * NETFS_READ_HOLE_CLEAR - Seek for data, clearing the part of the buffer
- * skipped over, then do as for IGNORE.
- *
- * NETFS_READ_HOLE_FAIL - Give ENODATA if we encounter a hole.
- */
- static inline
- int fscache_read(struct netfs_cache_resources *cres,
- loff_t start_pos,
- struct iov_iter *iter,
- enum netfs_read_from_hole read_hole,
- netfs_io_terminated_t term_func,
- void *term_func_priv)
- {
- const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
- return ops->read(cres, start_pos, iter, read_hole,
- term_func, term_func_priv);
- }
- /**
- * fscache_begin_write_operation - Begin a write operation for the netfs lib
- * @cres: The cache resources for the write being performed
- * @cookie: The cookie representing the cache object
- *
- * Begin a write operation on behalf of the netfs helper library. @cres
- * indicates the cache resources to which the operation state should be
- * attached; @cookie indicates the cache object that will be accessed.
- *
- * @cres->inval_counter is set from @cookie->inval_counter for comparison at
- * the end of the operation. This allows invalidation during the operation to
- * be detected by the caller.
- *
- * Returns:
- * * 0 - Success
- * * -ENOBUFS - No caching available
- * * Other error code from the cache, such as -ENOMEM.
- */
- static inline
- int fscache_begin_write_operation(struct netfs_cache_resources *cres,
- struct fscache_cookie *cookie)
- {
- if (fscache_cookie_enabled(cookie))
- return __fscache_begin_write_operation(cres, cookie);
- return -ENOBUFS;
- }
- /**
- * fscache_write - Start a write to the cache.
- * @cres: The cache resources to use
- * @start_pos: The beginning file offset in the cache file
- * @iter: The data to write - and also the length
- * @term_func: The function to call upon completion
- * @term_func_priv: The private data for @term_func
- *
- * Start a write to the cache. @cres indicates the cache object to write to and
- * must be obtained by a call to fscache_begin_operation() beforehand.
- *
- * The data to be written is obtained from the iterator, @iter, and that also
- * indicates the size of the operation. @start_pos is the start position in
- * the file.
- *
- * Upon termination of the operation, @term_func will be called and supplied
- * with @term_func_priv plus the amount of data written, if successful, or the
- * error code otherwise.
- */
- static inline
- int fscache_write(struct netfs_cache_resources *cres,
- loff_t start_pos,
- struct iov_iter *iter,
- netfs_io_terminated_t term_func,
- void *term_func_priv)
- {
- const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
- return ops->write(cres, start_pos, iter, term_func, term_func_priv);
- }
- /**
- * fscache_clear_page_bits - Clear the PG_fscache bits from a set of pages
- * @mapping: The netfs inode to use as the source
- * @start: The start position in @mapping
- * @len: The amount of data to unlock
- * @caching: If PG_fscache has been set
- *
- * Clear the PG_fscache flag from a sequence of pages and wake up anyone who's
- * waiting.
- */
- static inline void fscache_clear_page_bits(struct address_space *mapping,
- loff_t start, size_t len,
- bool caching)
- {
- if (caching)
- __fscache_clear_page_bits(mapping, start, len);
- }
- /**
- * fscache_write_to_cache - Save a write to the cache and clear PG_fscache
- * @cookie: The cookie representing the cache object
- * @mapping: The netfs inode to use as the source
- * @start: The start position in @mapping
- * @len: The amount of data to write back
- * @i_size: The new size of the inode
- * @term_func: The function to call upon completion
- * @term_func_priv: The private data for @term_func
- * @caching: If PG_fscache has been set
- *
- * Helper function for a netfs to write dirty data from an inode into the cache
- * object that's backing it.
- *
- * @start and @len describe the range of the data. This does not need to be
- * page-aligned, but to satisfy DIO requirements, the cache may expand it up to
- * the page boundaries on either end. All the pages covering the range must be
- * marked with PG_fscache.
- *
- * If given, @term_func will be called upon completion and supplied with
- * @term_func_priv. Note that the PG_fscache flags will have been cleared by
- * this point, so the netfs must retain its own pin on the mapping.
- */
- static inline void fscache_write_to_cache(struct fscache_cookie *cookie,
- struct address_space *mapping,
- loff_t start, size_t len, loff_t i_size,
- netfs_io_terminated_t term_func,
- void *term_func_priv,
- bool caching)
- {
- if (caching)
- __fscache_write_to_cache(cookie, mapping, start, len, i_size,
- term_func, term_func_priv, caching);
- else if (term_func)
- term_func(term_func_priv, -ENOBUFS, false);
- }
- #if __fscache_available
- bool fscache_dirty_folio(struct address_space *mapping, struct folio *folio,
- struct fscache_cookie *cookie);
- #else
- #define fscache_dirty_folio(MAPPING, FOLIO, COOKIE) \
- filemap_dirty_folio(MAPPING, FOLIO)
- #endif
- /**
- * fscache_unpin_writeback - Unpin writeback resources
- * @wbc: The writeback control
- * @cookie: The cookie referring to the cache object
- *
- * Unpin the writeback resources pinned by fscache_dirty_folio(). This is
- * intended to be called by the netfs's ->write_inode() method.
- */
- static inline void fscache_unpin_writeback(struct writeback_control *wbc,
- struct fscache_cookie *cookie)
- {
- if (wbc->unpinned_fscache_wb)
- fscache_unuse_cookie(cookie, NULL, NULL);
- }
- /**
- * fscache_clear_inode_writeback - Clear writeback resources pinned by an inode
- * @cookie: The cookie referring to the cache object
- * @inode: The inode to clean up
- * @aux: Auxiliary data to apply to the inode
- *
- * Clear any writeback resources held by an inode when the inode is evicted.
- * This must be called before clear_inode() is called.
- */
- static inline void fscache_clear_inode_writeback(struct fscache_cookie *cookie,
- struct inode *inode,
- const void *aux)
- {
- if (inode->i_state & I_PINNING_FSCACHE_WB) {
- loff_t i_size = i_size_read(inode);
- fscache_unuse_cookie(cookie, aux, &i_size);
- }
- }
- /**
- * fscache_note_page_release - Note that a netfs page got released
- * @cookie: The cookie corresponding to the file
- *
- * Note that a page that has been copied to the cache has been released. This
- * means that future reads will need to look in the cache to see if it's there.
- */
- static inline
- void fscache_note_page_release(struct fscache_cookie *cookie)
- {
- /* If we've written data to the cache (HAVE_DATA) and there wasn't any
- * data in the cache when we started (NO_DATA_TO_READ), it may no
- * longer be true that we can skip reading from the cache - so clear
- * the flag that causes reads to be skipped.
- */
- if (cookie &&
- test_bit(FSCACHE_COOKIE_HAVE_DATA, &cookie->flags) &&
- test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags))
- clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
- }
- #endif /* _LINUX_FSCACHE_H */
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