release/src-rt-6.x.4708/linux/linux-2.6.36/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                                          const char *,
  78                                          struct nfs_clone_mount *);
  79 extern void nfs_fscache_release_super_cookie(struct super_block *);
  80
  81 extern void nfs_fscache_init_inode_cookie(struct inode *);
  82 extern void nfs_fscache_release_inode_cookie(struct inode *);
  83 extern void nfs_fscache_zap_inode_cookie(struct inode *);
  84 extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);
  85 extern void nfs_fscache_reset_inode_cookie(struct inode *);
  86
  87 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  88 extern int nfs_fscache_release_page(struct page *, gfp_t);
  89
  90 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  91                                        struct inode *, struct page *);
  92 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
  93                                         struct inode *, struct address_space *,
  94                                         struct list_head *, unsigned *);
  95 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
  96
  97 /*
  98  * wait for a page to complete writing to the cache
  99  */
 100 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 101                                                   struct page *page)
 102 {
 103         if (PageFsCache(page))
 104                 fscache_wait_on_page_write(nfsi->fscache, page);
 105 }
 106
 107 /*
 108  * release the caching state associated with a page if undergoing complete page
 109  * invalidation
 110  */
 111 static inline void nfs_fscache_invalidate_page(struct page *page,
 112                                                struct inode *inode)
 113 {
 114         if (PageFsCache(page))
 115                 __nfs_fscache_invalidate_page(page, inode);
 116 }
 117
 118 /*
 119  * Retrieve a page from an inode data storage object.
 120  */
 121 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 122                                             struct inode *inode,
 123                                             struct page *page)
 124 {
 125         if (NFS_I(inode)->fscache)
 126                 return __nfs_readpage_from_fscache(ctx, inode, page);
 127         return -ENOBUFS;
 128 }
 129
 130 /*
 131  * Retrieve a set of pages from an inode data storage object.
 132  */
 133 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 134                                              struct inode *inode,
 135                                              struct address_space *mapping,
 136                                              struct list_head *pages,
 137                                              unsigned *nr_pages)
 138 {
 139         if (NFS_I(inode)->fscache)
 140                 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 141                                                     nr_pages);
 142         return -ENOBUFS;
 143 }
 144
 145 /*
 146  * Store a page newly fetched from the server in an inode data storage object
 147  * in the cache.
 148  */
 149 static inline void nfs_readpage_to_fscache(struct inode *inode,
 150                                            struct page *page,
 151                                            int sync)
 152 {
 153         if (PageFsCache(page))
 154                 __nfs_readpage_to_fscache(inode, page, sync);
 155 }
 156
 157 /*
 158  * indicate the client caching state as readable text
 159  */
 160 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 161 {
 162         if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
 163                 return "yes";
 164         return "no ";
 165 }
 166
 167
 168 #else /* CONFIG_NFS_FSCACHE */
 169 static inline int nfs_fscache_register(void) { return 0; }
 170 static inline void nfs_fscache_unregister(void) {}
 171
 172 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 173 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 174
 175 static inline void nfs_fscache_get_super_cookie(
 176         struct super_block *sb,
 177         const char *uniq,
 178         struct nfs_clone_mount *mntdata)
 179 {
 180 }
 181 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 182
 183 static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
 184 static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
 185 static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
 186 static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
 187                                                 struct file *filp) {}
 188 static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
 189
 190 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 191 {
 192         return 1; /* True: may release page */
 193 }
 194 static inline void nfs_fscache_invalidate_page(struct page *page,
 195                                                struct inode *inode) {}
 196 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 197                                                   struct page *page) {}
 198
 199 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 200                                             struct inode *inode,
 201                                             struct page *page)
 202 {
 203         return -ENOBUFS;
 204 }
 205 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 206                                              struct inode *inode,
 207                                              struct address_space *mapping,
 208                                              struct list_head *pages,
 209                                              unsigned *nr_pages)
 210 {
 211         return -ENOBUFS;
 212 }
 213 static inline void nfs_readpage_to_fscache(struct inode *inode,
 214                                            struct page *page, int sync) {}
 215
 216 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 217 {
 218         return "no ";
 219 }
 220
 221 #endif /* CONFIG_NFS_FSCACHE */
 222 #endif /* _NFS_FSCACHE_H */