651 lines
24 KiB
C
651 lines
24 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* General filesystem caching interface
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*
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* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* NOTE!!! See:
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*
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* Documentation/filesystems/caching/netfs-api.rst
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*
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* for a description of the network filesystem interface declared here.
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*/
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#ifndef _LINUX_FSCACHE_H
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#define _LINUX_FSCACHE_H
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#include <linux/fs.h>
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#include <linux/netfs.h>
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#include <linux/writeback.h>
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#if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
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#define __fscache_available (1)
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#define fscache_available() (1)
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#define fscache_volume_valid(volume) (volume)
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#define fscache_cookie_valid(cookie) (cookie)
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#define fscache_resources_valid(cres) ((cres)->cache_priv)
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#define fscache_cookie_enabled(cookie) (cookie && !test_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
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#else
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#define __fscache_available (0)
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#define fscache_available() (0)
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#define fscache_volume_valid(volume) (0)
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#define fscache_cookie_valid(cookie) (0)
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#define fscache_resources_valid(cres) (false)
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#define fscache_cookie_enabled(cookie) (0)
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#endif
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struct fscache_cookie;
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#define FSCACHE_ADV_SINGLE_CHUNK 0x01 /* The object is a single chunk of data */
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#define FSCACHE_ADV_WRITE_CACHE 0x00 /* Do cache if written to locally */
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#define FSCACHE_ADV_WRITE_NOCACHE 0x02 /* Don't cache if written to locally */
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#define FSCACHE_ADV_WANT_CACHE_SIZE 0x04 /* Retrieve cache size at runtime */
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#define FSCACHE_INVAL_DIO_WRITE 0x01 /* Invalidate due to DIO write */
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enum fscache_want_state {
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FSCACHE_WANT_PARAMS,
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FSCACHE_WANT_WRITE,
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FSCACHE_WANT_READ,
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};
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/*
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* Data object state.
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*/
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enum fscache_cookie_state {
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FSCACHE_COOKIE_STATE_QUIESCENT, /* The cookie is uncached */
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FSCACHE_COOKIE_STATE_LOOKING_UP, /* The cache object is being looked up */
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FSCACHE_COOKIE_STATE_CREATING, /* The cache object is being created */
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FSCACHE_COOKIE_STATE_ACTIVE, /* The cache is active, readable and writable */
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FSCACHE_COOKIE_STATE_INVALIDATING, /* The cache is being invalidated */
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FSCACHE_COOKIE_STATE_FAILED, /* The cache failed, withdraw to clear */
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FSCACHE_COOKIE_STATE_LRU_DISCARDING, /* The cookie is being discarded by the LRU */
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FSCACHE_COOKIE_STATE_WITHDRAWING, /* The cookie is being withdrawn */
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FSCACHE_COOKIE_STATE_RELINQUISHING, /* The cookie is being relinquished */
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FSCACHE_COOKIE_STATE_DROPPED, /* The cookie has been dropped */
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#define FSCACHE_COOKIE_STATE__NR (FSCACHE_COOKIE_STATE_DROPPED + 1)
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} __attribute__((mode(byte)));
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/*
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* Volume representation cookie.
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*/
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struct fscache_volume {
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refcount_t ref;
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atomic_t n_cookies; /* Number of data cookies in volume */
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atomic_t n_accesses; /* Number of cache accesses in progress */
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unsigned int debug_id;
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unsigned int key_hash; /* Hash of key string */
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u8 *key; /* Volume ID, eg. "afs@example.com@1234" */
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struct list_head proc_link; /* Link in /proc/fs/fscache/volumes */
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struct hlist_bl_node hash_link; /* Link in hash table */
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struct work_struct work;
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struct fscache_cache *cache; /* The cache in which this resides */
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void *cache_priv; /* Cache private data */
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spinlock_t lock;
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unsigned long flags;
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#define FSCACHE_VOLUME_RELINQUISHED 0 /* Volume is being cleaned up */
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#define FSCACHE_VOLUME_INVALIDATE 1 /* Volume was invalidated */
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#define FSCACHE_VOLUME_COLLIDED_WITH 2 /* Volume was collided with */
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#define FSCACHE_VOLUME_ACQUIRE_PENDING 3 /* Volume is waiting to complete acquisition */
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#define FSCACHE_VOLUME_CREATING 4 /* Volume is being created on disk */
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u8 coherency_len; /* Length of the coherency data */
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u8 coherency[]; /* Coherency data */
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};
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/*
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* Data file representation cookie.
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* - a file will only appear in one cache
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* - a request to cache a file may or may not be honoured, subject to
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* constraints such as disk space
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* - indices are created on disk just-in-time
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*/
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struct fscache_cookie {
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refcount_t ref;
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atomic_t n_active; /* number of active users of cookie */
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atomic_t n_accesses; /* Number of cache accesses in progress */
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unsigned int debug_id;
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unsigned int inval_counter; /* Number of invalidations made */
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spinlock_t lock;
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struct fscache_volume *volume; /* Parent volume of this file. */
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void *cache_priv; /* Cache-side representation */
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struct hlist_bl_node hash_link; /* Link in hash table */
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struct list_head proc_link; /* Link in proc list */
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struct list_head commit_link; /* Link in commit queue */
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struct work_struct work; /* Commit/relinq/withdraw work */
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loff_t object_size; /* Size of the netfs object */
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unsigned long unused_at; /* Time at which unused (jiffies) */
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unsigned long flags;
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#define FSCACHE_COOKIE_RELINQUISHED 0 /* T if cookie has been relinquished */
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#define FSCACHE_COOKIE_RETIRED 1 /* T if this cookie has retired on relinq */
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#define FSCACHE_COOKIE_IS_CACHING 2 /* T if this cookie is cached */
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#define FSCACHE_COOKIE_NO_DATA_TO_READ 3 /* T if this cookie has nothing to read */
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#define FSCACHE_COOKIE_NEEDS_UPDATE 4 /* T if attrs have been updated */
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#define FSCACHE_COOKIE_HAS_BEEN_CACHED 5 /* T if cookie needs withdraw-on-relinq */
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#define FSCACHE_COOKIE_DISABLED 6 /* T if cookie has been disabled */
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#define FSCACHE_COOKIE_LOCAL_WRITE 7 /* T if cookie has been modified locally */
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#define FSCACHE_COOKIE_NO_ACCESS_WAKE 8 /* T if no wake when n_accesses goes 0 */
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#define FSCACHE_COOKIE_DO_RELINQUISH 9 /* T if this cookie needs relinquishment */
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#define FSCACHE_COOKIE_DO_WITHDRAW 10 /* T if this cookie needs withdrawing */
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#define FSCACHE_COOKIE_DO_LRU_DISCARD 11 /* T if this cookie needs LRU discard */
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#define FSCACHE_COOKIE_DO_PREP_TO_WRITE 12 /* T if cookie needs write preparation */
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#define FSCACHE_COOKIE_HAVE_DATA 13 /* T if this cookie has data stored */
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#define FSCACHE_COOKIE_IS_HASHED 14 /* T if this cookie is hashed */
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#define FSCACHE_COOKIE_DO_INVALIDATE 15 /* T if cookie needs invalidation */
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enum fscache_cookie_state state;
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u8 advice; /* FSCACHE_ADV_* */
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u8 key_len; /* Length of index key */
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u8 aux_len; /* Length of auxiliary data */
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u32 key_hash; /* Hash of volume, key, len */
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union {
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void *key; /* Index key */
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u8 inline_key[16]; /* - If the key is short enough */
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};
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union {
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void *aux; /* Auxiliary data */
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u8 inline_aux[8]; /* - If the aux data is short enough */
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};
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};
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/*
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* slow-path functions for when there is actually caching available, and the
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* netfs does actually have a valid token
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* - these are not to be called directly
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* - these are undefined symbols when FS-Cache is not configured and the
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* optimiser takes care of not using them
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*/
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extern struct fscache_volume *__fscache_acquire_volume(const char *, const char *,
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const void *, size_t);
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extern void __fscache_relinquish_volume(struct fscache_volume *, const void *, bool);
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extern struct fscache_cookie *__fscache_acquire_cookie(
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struct fscache_volume *,
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u8,
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const void *, size_t,
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const void *, size_t,
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loff_t);
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extern void __fscache_use_cookie(struct fscache_cookie *, bool);
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extern void __fscache_unuse_cookie(struct fscache_cookie *, const void *, const loff_t *);
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extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool);
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extern void __fscache_resize_cookie(struct fscache_cookie *, loff_t);
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extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t, unsigned int);
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extern int __fscache_begin_read_operation(struct netfs_cache_resources *, struct fscache_cookie *);
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extern int __fscache_begin_write_operation(struct netfs_cache_resources *, struct fscache_cookie *);
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extern void __fscache_write_to_cache(struct fscache_cookie *, struct address_space *,
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loff_t, size_t, loff_t, netfs_io_terminated_t, void *,
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bool);
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extern void __fscache_clear_page_bits(struct address_space *, loff_t, size_t);
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/**
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* fscache_acquire_volume - Register a volume as desiring caching services
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* @volume_key: An identification string for the volume
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* @cache_name: The name of the cache to use (or NULL for the default)
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* @coherency_data: Piece of arbitrary coherency data to check (or NULL)
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* @coherency_len: The size of the coherency data
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*
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* Register a volume as desiring caching services if they're available. The
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* caller must provide an identifier for the volume and may also indicate which
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* cache it should be in. If a preexisting volume entry is found in the cache,
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* the coherency data must match otherwise the entry will be invalidated.
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*
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* Returns a cookie pointer on success, -ENOMEM if out of memory or -EBUSY if a
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* cache volume of that name is already acquired. Note that "NULL" is a valid
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* cookie pointer and can be returned if caching is refused.
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*/
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static inline
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struct fscache_volume *fscache_acquire_volume(const char *volume_key,
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const char *cache_name,
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const void *coherency_data,
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size_t coherency_len)
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{
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if (!fscache_available())
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return NULL;
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return __fscache_acquire_volume(volume_key, cache_name,
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coherency_data, coherency_len);
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}
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/**
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* fscache_relinquish_volume - Cease caching a volume
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* @volume: The volume cookie
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* @coherency_data: Piece of arbitrary coherency data to set (or NULL)
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* @invalidate: True if the volume should be invalidated
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*
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* Indicate that a filesystem no longer desires caching services for a volume.
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* The caller must have relinquished all file cookies prior to calling this.
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* The stored coherency data is updated.
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*/
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static inline
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void fscache_relinquish_volume(struct fscache_volume *volume,
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const void *coherency_data,
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bool invalidate)
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{
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if (fscache_volume_valid(volume))
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__fscache_relinquish_volume(volume, coherency_data, invalidate);
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}
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/**
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* fscache_acquire_cookie - Acquire a cookie to represent a cache object
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* @volume: The volume in which to locate/create this cookie
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* @advice: Advice flags (FSCACHE_COOKIE_ADV_*)
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* @index_key: The index key for this cookie
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* @index_key_len: Size of the index key
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* @aux_data: The auxiliary data for the cookie (may be NULL)
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* @aux_data_len: Size of the auxiliary data buffer
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* @object_size: The initial size of object
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*
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* Acquire a cookie to represent a data file within the given cache volume.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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struct fscache_cookie *fscache_acquire_cookie(struct fscache_volume *volume,
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u8 advice,
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const void *index_key,
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size_t index_key_len,
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const void *aux_data,
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size_t aux_data_len,
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loff_t object_size)
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{
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if (!fscache_volume_valid(volume))
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return NULL;
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return __fscache_acquire_cookie(volume, advice,
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index_key, index_key_len,
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aux_data, aux_data_len,
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object_size);
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}
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/**
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* fscache_use_cookie - Request usage of cookie attached to an object
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* @cookie: The cookie representing the cache object
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* @will_modify: If cache is expected to be modified locally
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*
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* Request usage of the cookie attached to an object. The caller should tell
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* the cache if the object's contents are about to be modified locally and then
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* the cache can apply the policy that has been set to handle this case.
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*/
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static inline void fscache_use_cookie(struct fscache_cookie *cookie,
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bool will_modify)
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{
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if (fscache_cookie_valid(cookie))
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__fscache_use_cookie(cookie, will_modify);
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}
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/**
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* fscache_unuse_cookie - Cease usage of cookie attached to an object
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* @cookie: The cookie representing the cache object
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* @aux_data: Updated auxiliary data (or NULL)
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* @object_size: Revised size of the object (or NULL)
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*
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* Cease usage of the cookie attached to an object. When the users count
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* reaches zero then the cookie relinquishment will be permitted to proceed.
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*/
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static inline void fscache_unuse_cookie(struct fscache_cookie *cookie,
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const void *aux_data,
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const loff_t *object_size)
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{
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if (fscache_cookie_valid(cookie))
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__fscache_unuse_cookie(cookie, aux_data, object_size);
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}
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/**
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* fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding
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* it
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* @cookie: The cookie being returned
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* @retire: True if the cache object the cookie represents is to be discarded
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*
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* This function returns a cookie to the cache, forcibly discarding the
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* associated cache object if retire is set to true.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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void fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
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{
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if (fscache_cookie_valid(cookie))
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__fscache_relinquish_cookie(cookie, retire);
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}
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/*
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* Find the auxiliary data on a cookie.
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*/
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static inline void *fscache_get_aux(struct fscache_cookie *cookie)
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{
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if (cookie->aux_len <= sizeof(cookie->inline_aux))
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return cookie->inline_aux;
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else
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return cookie->aux;
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}
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/*
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* Update the auxiliary data on a cookie.
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*/
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static inline
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void fscache_update_aux(struct fscache_cookie *cookie,
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const void *aux_data, const loff_t *object_size)
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{
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void *p = fscache_get_aux(cookie);
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if (aux_data && p)
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memcpy(p, aux_data, cookie->aux_len);
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if (object_size)
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cookie->object_size = *object_size;
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}
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#ifdef CONFIG_FSCACHE_STATS
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extern atomic_t fscache_n_updates;
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#endif
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static inline
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void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
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const loff_t *object_size)
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{
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#ifdef CONFIG_FSCACHE_STATS
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atomic_inc(&fscache_n_updates);
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#endif
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fscache_update_aux(cookie, aux_data, object_size);
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smp_wmb();
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set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
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}
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/**
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* fscache_update_cookie - Request that a cache object be updated
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* @cookie: The cookie representing the cache object
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* @aux_data: The updated auxiliary data for the cookie (may be NULL)
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* @object_size: The current size of the object (may be NULL)
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*
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* Request an update of the index data for the cache object associated with the
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* cookie. The auxiliary data on the cookie will be updated first if @aux_data
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* is set and the object size will be updated and the object possibly trimmed
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* if @object_size is set.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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void fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data,
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const loff_t *object_size)
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{
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if (fscache_cookie_enabled(cookie))
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__fscache_update_cookie(cookie, aux_data, object_size);
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}
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/**
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* fscache_resize_cookie - Request that a cache object be resized
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* @cookie: The cookie representing the cache object
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* @new_size: The new size of the object (may be NULL)
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*
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* Request that the size of an object be changed.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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void fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size)
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{
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if (fscache_cookie_enabled(cookie))
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__fscache_resize_cookie(cookie, new_size);
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}
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/**
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* fscache_invalidate - Notify cache that an object needs invalidation
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* @cookie: The cookie representing the cache object
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* @aux_data: The updated auxiliary data for the cookie (may be NULL)
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* @size: The revised size of the object.
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* @flags: Invalidation flags (FSCACHE_INVAL_*)
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*
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* Notify the cache that an object is needs to be invalidated and that it
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* should abort any retrievals or stores it is doing on the cache. This
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* increments inval_counter on the cookie which can be used by the caller to
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* reconsider I/O requests as they complete.
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*
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* If @flags has FSCACHE_INVAL_DIO_WRITE set, this indicates that this is due
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* to a direct I/O write and will cause caching to be disabled on this cookie
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* until it is completely unused.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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void fscache_invalidate(struct fscache_cookie *cookie,
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const void *aux_data, loff_t size, unsigned int flags)
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{
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if (fscache_cookie_enabled(cookie))
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__fscache_invalidate(cookie, aux_data, size, flags);
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}
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/**
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* fscache_operation_valid - Return true if operations resources are usable
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* @cres: The resources to check.
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*
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* Returns a pointer to the operations table if usable or NULL if not.
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*/
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static inline
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const struct netfs_cache_ops *fscache_operation_valid(const struct netfs_cache_resources *cres)
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{
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return fscache_resources_valid(cres) ? cres->ops : NULL;
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}
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/**
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* fscache_begin_read_operation - Begin a read operation for the netfs lib
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* @cres: The cache resources for the read being performed
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* @cookie: The cookie representing the cache object
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*
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* Begin a read operation on behalf of the netfs helper library. @cres
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* indicates the cache resources to which the operation state should be
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* 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_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);
|
|
|
|
}
|
|
|
|
/**
|
|
* 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 */
|