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Dan Magenheimer077b1f82011-05-26 10:01:36 -06001#ifndef _LINUX_CLEANCACHE_H
2#define _LINUX_CLEANCACHE_H
3
4#include <linux/fs.h>
5#include <linux/exportfs.h>
6#include <linux/mm.h>
7
8#define CLEANCACHE_KEY_MAX 6
9
10/*
11 * cleancache requires every file with a page in cleancache to have a
12 * unique key unless/until the file is removed/truncated. For some
13 * filesystems, the inode number is unique, but for "modern" filesystems
14 * an exportable filehandle is required (see exportfs.h)
15 */
16struct cleancache_filekey {
17 union {
18 ino_t ino;
19 __u32 fh[CLEANCACHE_KEY_MAX];
20 u32 key[CLEANCACHE_KEY_MAX];
21 } u;
22};
23
24struct cleancache_ops {
25 int (*init_fs)(size_t);
26 int (*init_shared_fs)(char *uuid, size_t);
27 int (*get_page)(int, struct cleancache_filekey,
28 pgoff_t, struct page *);
29 void (*put_page)(int, struct cleancache_filekey,
30 pgoff_t, struct page *);
Dan Magenheimer91c6cc92012-01-12 14:03:25 -050031 void (*invalidate_page)(int, struct cleancache_filekey, pgoff_t);
32 void (*invalidate_inode)(int, struct cleancache_filekey);
33 void (*invalidate_fs)(int);
Dan Magenheimer077b1f82011-05-26 10:01:36 -060034};
35
36extern struct cleancache_ops
37 cleancache_register_ops(struct cleancache_ops *ops);
38extern void __cleancache_init_fs(struct super_block *);
39extern void __cleancache_init_shared_fs(char *, struct super_block *);
40extern int __cleancache_get_page(struct page *);
41extern void __cleancache_put_page(struct page *);
Dan Magenheimer31677602011-09-21 11:56:28 -040042extern void __cleancache_invalidate_page(struct address_space *, struct page *);
43extern void __cleancache_invalidate_inode(struct address_space *);
44extern void __cleancache_invalidate_fs(struct super_block *);
Dan Magenheimer077b1f82011-05-26 10:01:36 -060045extern int cleancache_enabled;
46
47#ifdef CONFIG_CLEANCACHE
48static inline bool cleancache_fs_enabled(struct page *page)
49{
50 return page->mapping->host->i_sb->cleancache_poolid >= 0;
51}
52static inline bool cleancache_fs_enabled_mapping(struct address_space *mapping)
53{
54 return mapping->host->i_sb->cleancache_poolid >= 0;
55}
56#else
57#define cleancache_enabled (0)
58#define cleancache_fs_enabled(_page) (0)
59#define cleancache_fs_enabled_mapping(_page) (0)
60#endif
61
62/*
63 * The shim layer provided by these inline functions allows the compiler
64 * to reduce all cleancache hooks to nothingness if CONFIG_CLEANCACHE
65 * is disabled, to a single global variable check if CONFIG_CLEANCACHE
66 * is enabled but no cleancache "backend" has dynamically enabled it,
67 * and, for the most frequent cleancache ops, to a single global variable
68 * check plus a superblock element comparison if CONFIG_CLEANCACHE is enabled
69 * and a cleancache backend has dynamically enabled cleancache, but the
70 * filesystem referenced by that cleancache op has not enabled cleancache.
71 * As a result, CONFIG_CLEANCACHE can be enabled by default with essentially
72 * no measurable performance impact.
73 */
74
75static inline void cleancache_init_fs(struct super_block *sb)
76{
77 if (cleancache_enabled)
78 __cleancache_init_fs(sb);
79}
80
81static inline void cleancache_init_shared_fs(char *uuid, struct super_block *sb)
82{
83 if (cleancache_enabled)
84 __cleancache_init_shared_fs(uuid, sb);
85}
86
87static inline int cleancache_get_page(struct page *page)
88{
89 int ret = -1;
90
91 if (cleancache_enabled && cleancache_fs_enabled(page))
92 ret = __cleancache_get_page(page);
93 return ret;
94}
95
96static inline void cleancache_put_page(struct page *page)
97{
98 if (cleancache_enabled && cleancache_fs_enabled(page))
99 __cleancache_put_page(page);
100}
101
Dan Magenheimer31677602011-09-21 11:56:28 -0400102static inline void cleancache_invalidate_page(struct address_space *mapping,
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600103 struct page *page)
104{
105 /* careful... page->mapping is NULL sometimes when this is called */
106 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
Dan Magenheimer31677602011-09-21 11:56:28 -0400107 __cleancache_invalidate_page(mapping, page);
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600108}
109
Dan Magenheimer31677602011-09-21 11:56:28 -0400110static inline void cleancache_invalidate_inode(struct address_space *mapping)
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600111{
112 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
Dan Magenheimer31677602011-09-21 11:56:28 -0400113 __cleancache_invalidate_inode(mapping);
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600114}
115
Dan Magenheimer31677602011-09-21 11:56:28 -0400116static inline void cleancache_invalidate_fs(struct super_block *sb)
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600117{
118 if (cleancache_enabled)
Dan Magenheimer31677602011-09-21 11:56:28 -0400119 __cleancache_invalidate_fs(sb);
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600120}
121
122#endif /* _LINUX_CLEANCACHE_H */