1 #ifndef _LINUX_CLEANCACHE_H
2 #define _LINUX_CLEANCACHE_H
5 #include <linux/exportfs.h>
8 #define CLEANCACHE_KEY_MAX 6
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)
16 struct cleancache_filekey {
19 __u32 fh[CLEANCACHE_KEY_MAX];
20 u32 key[CLEANCACHE_KEY_MAX];
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);
36 extern int cleancache_register_ops(struct cleancache_ops *ops);
37 extern void __cleancache_init_fs(struct super_block *);
38 extern void __cleancache_init_shared_fs(struct super_block *);
39 extern int __cleancache_get_page(struct page *);
40 extern void __cleancache_put_page(struct page *);
41 extern void __cleancache_invalidate_page(struct address_space *, struct page *);
42 extern void __cleancache_invalidate_inode(struct address_space *);
43 extern void __cleancache_invalidate_fs(struct super_block *);
45 #ifdef CONFIG_CLEANCACHE
46 #define cleancache_enabled (1)
47 static inline bool cleancache_fs_enabled(struct page *page)
49 return page->mapping->host->i_sb->cleancache_poolid >= 0;
51 static inline bool cleancache_fs_enabled_mapping(struct address_space *mapping)
53 return mapping->host->i_sb->cleancache_poolid >= 0;
56 #define cleancache_enabled (0)
57 #define cleancache_fs_enabled(_page) (0)
58 #define cleancache_fs_enabled_mapping(_page) (0)
62 * The shim layer provided by these inline functions allows the compiler
63 * to reduce all cleancache hooks to nothingness if CONFIG_CLEANCACHE
64 * is disabled, to a single global variable check if CONFIG_CLEANCACHE
65 * is enabled but no cleancache "backend" has dynamically enabled it,
66 * and, for the most frequent cleancache ops, to a single global variable
67 * check plus a superblock element comparison if CONFIG_CLEANCACHE is enabled
68 * and a cleancache backend has dynamically enabled cleancache, but the
69 * filesystem referenced by that cleancache op has not enabled cleancache.
70 * As a result, CONFIG_CLEANCACHE can be enabled by default with essentially
71 * no measurable performance impact.
74 static inline void cleancache_init_fs(struct super_block *sb)
76 if (cleancache_enabled)
77 __cleancache_init_fs(sb);
80 static inline void cleancache_init_shared_fs(struct super_block *sb)
82 if (cleancache_enabled)
83 __cleancache_init_shared_fs(sb);
86 static inline int cleancache_get_page(struct page *page)
90 if (cleancache_enabled && cleancache_fs_enabled(page))
91 ret = __cleancache_get_page(page);
95 static inline void cleancache_put_page(struct page *page)
97 if (cleancache_enabled && cleancache_fs_enabled(page))
98 __cleancache_put_page(page);
101 static inline void cleancache_invalidate_page(struct address_space *mapping,
104 /* careful... page->mapping is NULL sometimes when this is called */
105 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
106 __cleancache_invalidate_page(mapping, page);
109 static inline void cleancache_invalidate_inode(struct address_space *mapping)
111 if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
112 __cleancache_invalidate_inode(mapping);
115 static inline void cleancache_invalidate_fs(struct super_block *sb)
117 if (cleancache_enabled)
118 __cleancache_invalidate_fs(sb);
121 #endif /* _LINUX_CLEANCACHE_H */