Current File : //usr/src/linux-headers-5.15.0-125-generic/include/linux/fscache.h
/* 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 */
Mini Shell