mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 04:34:11 +08:00
25985edced
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
647 lines
21 KiB
C
647 lines
21 KiB
C
/* General filesystem caching interface
|
|
*
|
|
* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* NOTE!!! See:
|
|
*
|
|
* Documentation/filesystems/caching/netfs-api.txt
|
|
*
|
|
* 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>
|
|
|
|
#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
|
|
|
|
|
|
/*
|
|
* overload PG_private_2 to give us PG_fscache - this is used to indicate that
|
|
* a page is currently backed by a local disk cache
|
|
*/
|
|
#define PageFsCache(page) PagePrivate2((page))
|
|
#define SetPageFsCache(page) SetPagePrivate2((page))
|
|
#define ClearPageFsCache(page) ClearPagePrivate2((page))
|
|
#define TestSetPageFsCache(page) TestSetPagePrivate2((page))
|
|
#define TestClearPageFsCache(page) TestClearPagePrivate2((page))
|
|
|
|
/* 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;
|
|
|
|
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);
|
|
|
|
/* get an index key
|
|
* - should store the key data in the buffer
|
|
* - should return the amount of data stored
|
|
* - not permitted to return an error
|
|
* - the netfs data from the cookie being used as the source is
|
|
* presented
|
|
*/
|
|
uint16_t (*get_key)(const void *cookie_netfs_data,
|
|
void *buffer,
|
|
uint16_t bufmax);
|
|
|
|
/* get certain file attributes from the netfs data
|
|
* - this function can be absent for an index
|
|
* - not permitted to return an error
|
|
* - the netfs data from the cookie being used as the source is
|
|
* presented
|
|
*/
|
|
void (*get_attr)(const void *cookie_netfs_data, uint64_t *size);
|
|
|
|
/* get the auxiliary data from netfs data
|
|
* - this function can be absent if the index carries no state data
|
|
* - should store the auxiliary data in the buffer
|
|
* - should return the amount of amount stored
|
|
* - not permitted to return an error
|
|
* - the netfs data from the cookie being used as the source is
|
|
* presented
|
|
*/
|
|
uint16_t (*get_aux)(const void *cookie_netfs_data,
|
|
void *buffer,
|
|
uint16_t bufmax);
|
|
|
|
/* 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
|
|
*/
|
|
enum fscache_checkaux (*check_aux)(void *cookie_netfs_data,
|
|
const void *data,
|
|
uint16_t datalen);
|
|
|
|
/* 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 pages that now have cache metadata retained
|
|
* - this function should mark the specified pages as now being cached
|
|
* - the pages will have been marked with PG_fscache before this is
|
|
* called, so this is optional
|
|
*/
|
|
void (*mark_pages_cached)(void *cookie_netfs_data,
|
|
struct address_space *mapping,
|
|
struct pagevec *cached_pvec);
|
|
|
|
/* indicate the cookie is no longer cached
|
|
* - this function is called when the backing store currently caching
|
|
* a cookie is removed
|
|
* - the netfs should use this to clean up any markers indicating
|
|
* cached pages
|
|
* - this is mandatory for any object that may have data
|
|
*/
|
|
void (*now_uncached)(void *cookie_netfs_data);
|
|
};
|
|
|
|
/*
|
|
* 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;
|
|
struct list_head link; /* internal link */
|
|
};
|
|
|
|
/*
|
|
* 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 *,
|
|
void *);
|
|
extern void __fscache_relinquish_cookie(struct fscache_cookie *, int);
|
|
extern void __fscache_update_cookie(struct fscache_cookie *);
|
|
extern int __fscache_attr_changed(struct fscache_cookie *);
|
|
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 *, 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);
|
|
|
|
/**
|
|
* 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.txt 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.txt 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.txt 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.txt 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
|
|
* @netfs_data: An arbitrary piece of data to be kept in the cookie to
|
|
* represent the cache object to the netfs
|
|
*
|
|
* 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.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
struct fscache_cookie *fscache_acquire_cookie(
|
|
struct fscache_cookie *parent,
|
|
const struct fscache_cookie_def *def,
|
|
void *netfs_data)
|
|
{
|
|
if (fscache_cookie_valid(parent))
|
|
return __fscache_acquire_cookie(parent, def, netfs_data);
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* fscache_relinquish_cookie - Return the cookie to the cache, maybe discarding
|
|
* it
|
|
* @cookie: The cookie being returned
|
|
* @retire: True if the cache object the cookie represents is to be discarded
|
|
*
|
|
* This function returns a cookie to the cache, forcibly discarding the
|
|
* associated cache object if retire is set to true.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
__fscache_relinquish_cookie(cookie, retire);
|
|
}
|
|
|
|
/**
|
|
* fscache_update_cookie - Request that a cache object be updated
|
|
* @cookie: The cookie representing the cache object
|
|
*
|
|
* Request an update of the index data for the cache object associated with the
|
|
* cookie.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
void fscache_update_cookie(struct fscache_cookie *cookie)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
__fscache_update_cookie(cookie);
|
|
}
|
|
|
|
/**
|
|
* 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.txt 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.txt 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.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
int fscache_attr_changed(struct fscache_cookie *cookie)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
return __fscache_attr_changed(cookie);
|
|
else
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/**
|
|
* 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.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size)
|
|
{
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/**
|
|
* 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.txt 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))
|
|
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.txt 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))
|
|
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.txt 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))
|
|
return __fscache_alloc_page(cookie, page, gfp);
|
|
else
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/**
|
|
* fscache_write_page - Request storage of a page in the cache
|
|
* @cookie: The cookie representing the cache object
|
|
* @page: The netfs page to store
|
|
* @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.txt for a complete
|
|
* description.
|
|
*/
|
|
static inline
|
|
int fscache_write_page(struct fscache_cookie *cookie,
|
|
struct page *page,
|
|
gfp_t gfp)
|
|
{
|
|
if (fscache_cookie_valid(cookie))
|
|
return __fscache_write_page(cookie, page, 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.txt 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.txt 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.txt 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 false;
|
|
}
|
|
|
|
#endif /* _LINUX_FSCACHE_H */
|