Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_CLEANCACHE_H
       3             : #define _LINUX_CLEANCACHE_H
       4             : 
       5             : #include <linux/fs.h>
       6             : #include <linux/exportfs.h>
       7             : #include <linux/mm.h>
       8             : 
       9             : #define CLEANCACHE_NO_POOL              -1
      10             : #define CLEANCACHE_NO_BACKEND           -2
      11             : #define CLEANCACHE_NO_BACKEND_SHARED    -3
      12             : 
      13             : #define CLEANCACHE_KEY_MAX 6
      14             : 
      15             : /*
      16             :  * cleancache requires every file with a page in cleancache to have a
      17             :  * unique key unless/until the file is removed/truncated.  For some
      18             :  * filesystems, the inode number is unique, but for "modern" filesystems
      19             :  * an exportable filehandle is required (see exportfs.h)
      20             :  */
      21             : struct cleancache_filekey {
      22             :         union {
      23             :                 ino_t ino;
      24             :                 __u32 fh[CLEANCACHE_KEY_MAX];
      25             :                 u32 key[CLEANCACHE_KEY_MAX];
      26             :         } u;
      27             : };
      28             : 
      29             : struct cleancache_ops {
      30             :         int (*init_fs)(size_t);
      31             :         int (*init_shared_fs)(uuid_t *uuid, size_t);
      32             :         int (*get_page)(int, struct cleancache_filekey,
      33             :                         pgoff_t, struct page *);
      34             :         void (*put_page)(int, struct cleancache_filekey,
      35             :                         pgoff_t, struct page *);
      36             :         void (*invalidate_page)(int, struct cleancache_filekey, pgoff_t);
      37             :         void (*invalidate_inode)(int, struct cleancache_filekey);
      38             :         void (*invalidate_fs)(int);
      39             : };
      40             : 
      41             : extern int cleancache_register_ops(const struct cleancache_ops *ops);
      42             : extern void __cleancache_init_fs(struct super_block *);
      43             : extern void __cleancache_init_shared_fs(struct super_block *);
      44             : extern int  __cleancache_get_page(struct page *);
      45             : extern void __cleancache_put_page(struct page *);
      46             : extern void __cleancache_invalidate_page(struct address_space *, struct page *);
      47             : extern void __cleancache_invalidate_inode(struct address_space *);
      48             : extern void __cleancache_invalidate_fs(struct super_block *);
      49             : 
      50             : #ifdef CONFIG_CLEANCACHE
      51             : #define cleancache_enabled (1)
      52       25494 : static inline bool cleancache_fs_enabled_mapping(struct address_space *mapping)
      53             : {
      54       25494 :         return mapping->host->i_sb->cleancache_poolid >= 0;
      55             : }
      56       21536 : static inline bool cleancache_fs_enabled(struct page *page)
      57             : {
      58       21536 :         return cleancache_fs_enabled_mapping(page->mapping);
      59             : }
      60             : #else
      61             : #define cleancache_enabled (0)
      62             : #define cleancache_fs_enabled(_page) (0)
      63             : #define cleancache_fs_enabled_mapping(_page) (0)
      64             : #endif
      65             : 
      66             : /*
      67             :  * The shim layer provided by these inline functions allows the compiler
      68             :  * to reduce all cleancache hooks to nothingness if CONFIG_CLEANCACHE
      69             :  * is disabled, to a single global variable check if CONFIG_CLEANCACHE
      70             :  * is enabled but no cleancache "backend" has dynamically enabled it,
      71             :  * and, for the most frequent cleancache ops, to a single global variable
      72             :  * check plus a superblock element comparison if CONFIG_CLEANCACHE is enabled
      73             :  * and a cleancache backend has dynamically enabled cleancache, but the
      74             :  * filesystem referenced by that cleancache op has not enabled cleancache.
      75             :  * As a result, CONFIG_CLEANCACHE can be enabled by default with essentially
      76             :  * no measurable performance impact.
      77             :  */
      78             : 
      79           2 : static inline void cleancache_init_fs(struct super_block *sb)
      80             : {
      81           2 :         if (cleancache_enabled)
      82           2 :                 __cleancache_init_fs(sb);
      83             : }
      84             : 
      85             : static inline void cleancache_init_shared_fs(struct super_block *sb)
      86             : {
      87             :         if (cleancache_enabled)
      88             :                 __cleancache_init_shared_fs(sb);
      89             : }
      90             : 
      91       21536 : static inline int cleancache_get_page(struct page *page)
      92             : {
      93       21536 :         if (cleancache_enabled && cleancache_fs_enabled(page))
      94           0 :                 return __cleancache_get_page(page);
      95             :         return -1;
      96             : }
      97             : 
      98           0 : static inline void cleancache_put_page(struct page *page)
      99             : {
     100           0 :         if (cleancache_enabled && cleancache_fs_enabled(page))
     101           0 :                 __cleancache_put_page(page);
     102           0 : }
     103             : 
     104           2 : static inline void cleancache_invalidate_page(struct address_space *mapping,
     105             :                                         struct page *page)
     106             : {
     107             :         /* careful... page->mapping is NULL sometimes when this is called */
     108           2 :         if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
     109           0 :                 __cleancache_invalidate_page(mapping, page);
     110           2 : }
     111             : 
     112        3956 : static inline void cleancache_invalidate_inode(struct address_space *mapping)
     113             : {
     114        3956 :         if (cleancache_enabled && cleancache_fs_enabled_mapping(mapping))
     115           0 :                 __cleancache_invalidate_inode(mapping);
     116        3956 : }
     117             : 
     118          99 : static inline void cleancache_invalidate_fs(struct super_block *sb)
     119             : {
     120          99 :         if (cleancache_enabled)
     121          99 :                 __cleancache_invalidate_fs(sb);
     122             : }
     123             : 
     124             : #endif /* _LINUX_CLEANCACHE_H */