124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
#ifndef _LINUX_CLEANCACHE_H
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#define _LINUX_CLEANCACHE_H
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#include <linux/fs.h>
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#include <linux/exportfs.h>
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#include <linux/mm.h>
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#define CLEANCACHE_NO_POOL -1
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#define CLEANCACHE_NO_BACKEND -2
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#define CLEANCACHE_NO_BACKEND_SHARED -3
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#define CLEANCACHE_KEY_MAX 6
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/*
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* cleancache requires every file with a page in cleancache to have a
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* unique key unless/until the file is removed/truncated. For some
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* filesystems, the inode number is unique, but for "modern" filesystems
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* an exportable filehandle is required (see exportfs.h)
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*/
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struct cleancache_filekey {
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union {
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ino_t ino;
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__u32 fh[CLEANCACHE_KEY_MAX];
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u32 key[CLEANCACHE_KEY_MAX];
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} u;
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};
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struct cleancache_ops {
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int (*init_fs)(size_t);
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int (*init_shared_fs)(uuid_t *uuid, size_t);
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int (*get_page)(int, struct cleancache_filekey,
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pgoff_t, struct page *);
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void (*put_page)(int, struct cleancache_filekey,
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pgoff_t, struct page *);
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void (*invalidate_page)(int, struct cleancache_filekey, pgoff_t);
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void (*invalidate_inode)(int, struct cleancache_filekey);
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void (*invalidate_fs)(int);
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};
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extern int cleancache_register_ops(const struct cleancache_ops *ops);
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extern void __cleancache_init_fs(struct super_block *);
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extern void __cleancache_init_shared_fs(struct super_block *);
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extern int __cleancache_get_page(struct page *);
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extern void __cleancache_put_page(struct page *);
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extern void __cleancache_invalidate_page(struct address_space *, struct page *);
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extern void __cleancache_invalidate_inode(struct address_space *);
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extern void __cleancache_invalidate_fs(struct super_block *);
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#ifdef CONFIG_CLEANCACHE
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#define cleancache_enabled (1)
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static inline bool cleancache_fs_enabled_mapping(struct address_space *mapping)
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{
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return mapping->host->i_sb->cleancache_poolid >= 0;
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}
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static inline bool cleancache_fs_enabled(struct page *page)
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{
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return cleancache_fs_enabled_mapping(page->mapping);
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}
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#else
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#define cleancache_enabled (0)
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#define cleancache_fs_enabled(_page) (0)
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#define cleancache_fs_enabled_mapping(_page) (0)
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#endif
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/*
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* The shim layer provided by these inline functions allows the compiler
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* to reduce all cleancache hooks to nothingness if CONFIG_CLEANCACHE
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* is disabled, to a single global variable check if CONFIG_CLEANCACHE
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* is enabled but no cleancache "backend" has dynamically enabled it,
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* and, for the most frequent cleancache ops, to a single global variable
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* check plus a superblock element comparison if CONFIG_CLEANCACHE is enabled
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* and a cleancache backend has dynamically enabled cleancache, but the
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* filesystem referenced by that cleancache op has not enabled cleancache.
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* As a result, CONFIG_CLEANCACHE can be enabled by default with essentially
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* no measurable performance impact.
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*/
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static inline void cleancache_init_fs(struct super_block *sb)
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{
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if (cleancache_enabled)
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__cleancache_init_fs(sb);
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}
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static inline void cleancache_init_shared_fs(struct super_block *sb)
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{
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if (cleancache_enabled)
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__cleancache_init_shared_fs(sb);
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}
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static inline int cleancache_get_page(struct page *page)
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{
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if (cleancache_enabled && cleancache_fs_enabled(page))
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return __cleancache_get_page(page);
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return -1;
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}
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static inline void cleancache_put_page(struct page *page)
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{
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if (cleancache_enabled && cleancache_fs_enabled(page))
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__cleancache_put_page(page);
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}
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static inline void cleancache_invalidate_page(struct address_space *mapping,
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struct page *page)
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{
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/* careful... page->mapping is NULL sometimes when this is called */
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if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
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__cleancache_invalidate_page(mapping, page);
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}
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static inline void cleancache_invalidate_inode(struct address_space *mapping)
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{
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if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
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__cleancache_invalidate_inode(mapping);
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}
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static inline void cleancache_invalidate_fs(struct super_block *sb)
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{
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if (cleancache_enabled)
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__cleancache_invalidate_fs(sb);
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}
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#endif /* _LINUX_CLEANCACHE_H */
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