Line data    Source code

       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             : 
      46             : #ifdef CONFIG_CLEANCACHE
      47             : #define cleancache_enabled (1)
      48             : static inline bool cleancache_fs_enabled(struct page *page)
      49             : {
      50      486456 :         return page->mapping->host->i_sb->cleancache_poolid >= 0;
      51             : }
      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             : 
      75             : static inline void cleancache_init_fs(struct super_block *sb)
      76             : {
      77             :         if (cleancache_enabled)
      78             :                 __cleancache_init_fs(sb);
      79             : }
      80             : 
      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             : 
      87      486456 : static inline int cleancache_get_page(struct page *page)
      88             : {
      89             :         int ret = -1;
      90             : 
      91      486456 :         if (cleancache_enabled && cleancache_fs_enabled(page))
      92      472988 :                 ret = __cleancache_get_page(page);
      93      486456 :         return ret;
      94             : }
      95             : 
      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             : 
     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             : 
     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             : 
     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 */