876 строки
30 KiB
C
876 строки
30 KiB
C
/* 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>
|
|
#include <linux/netfs.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
|
|
|
|
|
|
/* 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;
|
|
struct netfs_read_request;
|
|
|
|
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 {
|
|
refcount_t ref; /* 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 */
|
|
unsigned int debug_id;
|
|
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 */
|
|
struct list_head proc_link; /* Link in proc list */
|
|
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 fscache_cookie_valid(cookie) && 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 *);
|
|
|
|
#ifdef FSCACHE_USE_NEW_IO_API
|
|
extern int __fscache_begin_read_operation(struct netfs_read_request *, struct fscache_cookie *);
|
|
#else
|
|
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);
|
|
#endif /* FSCACHE_USE_NEW_IO_API */
|
|
|
|
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;
|
|
}
|
|
|
|
#ifdef FSCACHE_USE_NEW_IO_API
|
|
|
|
/**
|
|
* fscache_begin_read_operation - Begin a read operation for the netfs lib
|
|
* @rreq: The read request being undertaken
|
|
* @cookie: The cookie representing the cache object
|
|
*
|
|
* Begin a read operation on behalf of the netfs helper library. @rreq
|
|
* indicates the read request 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.
|
|
*
|
|
* 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_read_request *rreq,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
if (fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie))
|
|
return __fscache_begin_read_operation(rreq, cookie);
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
#else /* FSCACHE_USE_NEW_IO_API */
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
|
|
#endif /* FSCACHE_USE_NEW_IO_API */
|
|
|
|
/**
|
|
* 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 */
|