1 #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 */
16 struct cleancache_filekey {
17 union {
18 ino_t ino;
19 __u32 fh[CLEANCACHE_KEY_MAX];
20 u32 key[CLEANCACHE_KEY_MAX];
21 } u;
22 };
23
24 struct 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 *);
31 void (*invalidate_page)(int, struct cleancache_filekey, pgoff_t);
32 void (*invalidate_inode)(int, struct cleancache_filekey);
33 void (*invalidate_fs)(int);
34 };
35
36 extern struct cleancache_ops
37 cleancache_register_ops(struct cleancache_ops *ops);
38 extern void __cleancache_init_fs(struct super_block *);
39 extern void __cleancache_init_shared_fs(char *, struct super_block *);
40 extern int __cleancache_get_page(struct page *);
41 extern void __cleancache_put_page(struct page *);
42 extern void __cleancache_invalidate_page(struct address_space *, struct page *);
43 extern void __cleancache_invalidate_inode(struct address_space *);
44 extern void __cleancache_invalidate_fs(struct super_block *);
45 extern int cleancache_enabled;
46
47 #ifdef CONFIG_CLEANCACHE
cleancache_fs_enabled(struct page * page)48 static inline bool cleancache_fs_enabled(struct page *page)
49 {
50 return page->mapping->host->i_sb->cleancache_poolid >= 0;
51 }
cleancache_fs_enabled_mapping(struct address_space * mapping)52 static 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
cleancache_init_fs(struct super_block * sb)75 static inline void cleancache_init_fs(struct super_block *sb)
76 {
77 if (cleancache_enabled)
78 __cleancache_init_fs(sb);
79 }
80
cleancache_init_shared_fs(char * uuid,struct super_block * sb)81 static 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
cleancache_get_page(struct page * page)87 static 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
cleancache_put_page(struct page * page)96 static inline void cleancache_put_page(struct page *page)
97 {
98 if (cleancache_enabled && cleancache_fs_enabled(page))
99 __cleancache_put_page(page);
100 }
101
cleancache_invalidate_page(struct address_space * mapping,struct page * page)102 static inline void cleancache_invalidate_page(struct address_space *mapping,
103 struct page *page)
104 {
105 /* careful... page->mapping is NULL sometimes when this is called */
106 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
107 __cleancache_invalidate_page(mapping, page);
108 }
109
cleancache_invalidate_inode(struct address_space * mapping)110 static inline void cleancache_invalidate_inode(struct address_space *mapping)
111 {
112 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
113 __cleancache_invalidate_inode(mapping);
114 }
115
cleancache_invalidate_fs(struct super_block * sb)116 static inline void cleancache_invalidate_fs(struct super_block *sb)
117 {
118 if (cleancache_enabled)
119 __cleancache_invalidate_fs(sb);
120 }
121
122 #endif /* _LINUX_CLEANCACHE_H */
123