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077b1f83 DM |
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 *); | |
3167760f DM |
31 | /* |
32 | * NOTE: per akpm, flush_page, flush_inode and flush_fs will be | |
33 | * renamed to invalidate_* in a later commit in which all | |
34 | * dependencies (i.e Xen, zcache) will be renamed simultaneously | |
35 | */ | |
077b1f83 DM |
36 | void (*flush_page)(int, struct cleancache_filekey, pgoff_t); |
37 | void (*flush_inode)(int, struct cleancache_filekey); | |
38 | void (*flush_fs)(int); | |
39 | }; | |
40 | ||
41 | extern struct cleancache_ops | |
42 | cleancache_register_ops(struct cleancache_ops *ops); | |
43 | extern void __cleancache_init_fs(struct super_block *); | |
44 | extern void __cleancache_init_shared_fs(char *, struct super_block *); | |
45 | extern int __cleancache_get_page(struct page *); | |
46 | extern void __cleancache_put_page(struct page *); | |
3167760f DM |
47 | extern void __cleancache_invalidate_page(struct address_space *, struct page *); |
48 | extern void __cleancache_invalidate_inode(struct address_space *); | |
49 | extern void __cleancache_invalidate_fs(struct super_block *); | |
077b1f83 DM |
50 | extern int cleancache_enabled; |
51 | ||
52 | #ifdef CONFIG_CLEANCACHE | |
53 | static inline bool cleancache_fs_enabled(struct page *page) | |
54 | { | |
55 | return page->mapping->host->i_sb->cleancache_poolid >= 0; | |
56 | } | |
57 | static inline bool cleancache_fs_enabled_mapping(struct address_space *mapping) | |
58 | { | |
59 | return mapping->host->i_sb->cleancache_poolid >= 0; | |
60 | } | |
61 | #else | |
62 | #define cleancache_enabled (0) | |
63 | #define cleancache_fs_enabled(_page) (0) | |
64 | #define cleancache_fs_enabled_mapping(_page) (0) | |
65 | #endif | |
66 | ||
67 | /* | |
68 | * The shim layer provided by these inline functions allows the compiler | |
69 | * to reduce all cleancache hooks to nothingness if CONFIG_CLEANCACHE | |
70 | * is disabled, to a single global variable check if CONFIG_CLEANCACHE | |
71 | * is enabled but no cleancache "backend" has dynamically enabled it, | |
72 | * and, for the most frequent cleancache ops, to a single global variable | |
73 | * check plus a superblock element comparison if CONFIG_CLEANCACHE is enabled | |
74 | * and a cleancache backend has dynamically enabled cleancache, but the | |
75 | * filesystem referenced by that cleancache op has not enabled cleancache. | |
76 | * As a result, CONFIG_CLEANCACHE can be enabled by default with essentially | |
77 | * no measurable performance impact. | |
78 | */ | |
79 | ||
80 | static inline void cleancache_init_fs(struct super_block *sb) | |
81 | { | |
82 | if (cleancache_enabled) | |
83 | __cleancache_init_fs(sb); | |
84 | } | |
85 | ||
86 | static inline void cleancache_init_shared_fs(char *uuid, struct super_block *sb) | |
87 | { | |
88 | if (cleancache_enabled) | |
89 | __cleancache_init_shared_fs(uuid, sb); | |
90 | } | |
91 | ||
92 | static inline int cleancache_get_page(struct page *page) | |
93 | { | |
94 | int ret = -1; | |
95 | ||
96 | if (cleancache_enabled && cleancache_fs_enabled(page)) | |
97 | ret = __cleancache_get_page(page); | |
98 | return ret; | |
99 | } | |
100 | ||
101 | static inline void cleancache_put_page(struct page *page) | |
102 | { | |
103 | if (cleancache_enabled && cleancache_fs_enabled(page)) | |
104 | __cleancache_put_page(page); | |
105 | } | |
106 | ||
3167760f | 107 | static inline void cleancache_invalidate_page(struct address_space *mapping, |
077b1f83 DM |
108 | struct page *page) |
109 | { | |
110 | /* careful... page->mapping is NULL sometimes when this is called */ | |
111 | if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping)) | |
3167760f | 112 | __cleancache_invalidate_page(mapping, page); |
077b1f83 DM |
113 | } |
114 | ||
3167760f | 115 | static inline void cleancache_invalidate_inode(struct address_space *mapping) |
077b1f83 DM |
116 | { |
117 | if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping)) | |
3167760f | 118 | __cleancache_invalidate_inode(mapping); |
077b1f83 DM |
119 | } |
120 | ||
3167760f | 121 | static inline void cleancache_invalidate_fs(struct super_block *sb) |
077b1f83 DM |
122 | { |
123 | if (cleancache_enabled) | |
3167760f | 124 | __cleancache_invalidate_fs(sb); |
077b1f83 DM |
125 | } |
126 | ||
127 | #endif /* _LINUX_CLEANCACHE_H */ |