fs/nfs/fscache.h

   1 /* NFS filesystem cache interface definitions
   2  *
   3  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11
  12 #ifndef _NFS_FSCACHE_H
  13 #define _NFS_FSCACHE_H
  14
  15 #include <linux/nfs_fs.h>
  16 #include <linux/nfs_mount.h>
  17 #include <linux/nfs4_mount.h>
  18 #include <linux/fscache.h>
  19
  20 #ifdef CONFIG_NFS_FSCACHE
  21
  22 /*
  23  * set of NFS FS-Cache objects that form a superblock key
  24  */
  25 struct nfs_fscache_key {
  26         struct rb_node          node;
  27         struct nfs_client       *nfs_client;    /* the server */
  28
  29         /* the elements of the unique key - as used by nfs_compare_super() and
  30          * nfs_compare_mount_options() to distinguish superblocks */
  31         struct {
  32                 struct {
  33                         unsigned long   s_flags;        /* various flags
  34                                                          * (& NFS_MS_MASK) */
  35                 } super;
  36
  37                 struct {
  38                         struct nfs_fsid fsid;
  39                         int             flags;
  40                         unsigned int    rsize;          /* read size */
  41                         unsigned int    wsize;          /* write size */
  42                         unsigned int    acregmin;       /* attr cache timeouts */
  43                         unsigned int    acregmax;
  44                         unsigned int    acdirmin;
  45                         unsigned int    acdirmax;
  46                 } nfs_server;
  47
  48                 struct {
  49                         rpc_authflavor_t au_flavor;
  50                 } rpc_auth;
  51
  52                 /* uniquifier - can be used if nfs_server.flags includes
  53                  * NFS_MOUNT_UNSHARED  */
  54                 u8 uniq_len;
  55                 char uniquifier[0];
  56         } key;
  57 };
  58
  59 /*
  60  * fscache-index.c
  61  */
  62 extern struct fscache_netfs nfs_fscache_netfs;
  63 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  64 extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  65 extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  66
  67 extern int nfs_fscache_register(void);
  68 extern void nfs_fscache_unregister(void);
  69
  70 /*
  71  * fscache.c
  72  */
  73 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  74 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  75
  76 extern void nfs_fscache_get_super_cookie(struct super_block *,
  77                                          struct nfs_parsed_mount_data *);
  78 extern void nfs_fscache_release_super_cookie(struct super_block *);
  79
  80 extern void nfs_fscache_init_inode_cookie(struct inode *);
  81 extern void nfs_fscache_release_inode_cookie(struct inode *);
  82 extern void nfs_fscache_zap_inode_cookie(struct inode *);
  83 extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);
  84 extern void nfs_fscache_reset_inode_cookie(struct inode *);
  85
  86 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  87 extern int nfs_fscache_release_page(struct page *, gfp_t);
  88
  89 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  90                                        struct inode *, struct page *);
  91 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
  92                                         struct inode *, struct address_space *,
  93                                         struct list_head *, unsigned *);
  94
  95 /*
  96  * wait for a page to complete writing to the cache
  97  */
  98 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
  99                                                   struct page *page)
 100 {
 101         if (PageFsCache(page))
 102                 fscache_wait_on_page_write(nfsi->fscache, page);
 103 }
 104
 105 /*
 106  * release the caching state associated with a page if undergoing complete page
 107  * invalidation
 108  */
 109 static inline void nfs_fscache_invalidate_page(struct page *page,
 110                                                struct inode *inode)
 111 {
 112         if (PageFsCache(page))
 113                 __nfs_fscache_invalidate_page(page, inode);
 114 }
 115
 116 /*
 117  * Retrieve a page from an inode data storage object.
 118  */
 119 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 120                                             struct inode *inode,
 121                                             struct page *page)
 122 {
 123         if (NFS_I(inode)->fscache)
 124                 return __nfs_readpage_from_fscache(ctx, inode, page);
 125         return -ENOBUFS;
 126 }
 127
 128 /*
 129  * Retrieve a set of pages from an inode data storage object.
 130  */
 131 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 132                                              struct inode *inode,
 133                                              struct address_space *mapping,
 134                                              struct list_head *pages,
 135                                              unsigned *nr_pages)
 136 {
 137         if (NFS_I(inode)->fscache)
 138                 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 139                                                     nr_pages);
 140         return -ENOBUFS;
 141 }
 142
 143 #else /* CONFIG_NFS_FSCACHE */
 144 static inline int nfs_fscache_register(void) { return 0; }
 145 static inline void nfs_fscache_unregister(void) {}
 146
 147 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 148 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 149
 150 static inline void nfs_fscache_get_super_cookie(
 151         struct super_block *sb,
 152         struct nfs_parsed_mount_data *data)
 153 {
 154 }
 155 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 156
 157 static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
 158 static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
 159 static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
 160 static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
 161                                                 struct file *filp) {}
 162 static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
 163
 164 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 165 {
 166         return 1; /* True: may release page */
 167 }
 168 static inline void nfs_fscache_invalidate_page(struct page *page,
 169                                                struct inode *inode) {}
 170 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 171                                                   struct page *page) {}
 172
 173 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 174                                             struct inode *inode,
 175                                             struct page *page)
 176 {
 177         return -ENOBUFS;
 178 }
 179 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 180                                              struct inode *inode,
 181                                              struct address_space *mapping,
 182                                              struct list_head *pages,
 183                                              unsigned *nr_pages)
 184 {
 185         return -ENOBUFS;
 186 }
 187
 188 #endif /* CONFIG_NFS_FSCACHE */
 189 #endif /* _NFS_FSCACHE_H */