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 *, const char *, int);
  77 extern void nfs_fscache_release_super_cookie(struct super_block *);
  78
  79 extern void nfs_fscache_init_inode(struct inode *);
  80 extern void nfs_fscache_clear_inode(struct inode *);
  81 extern void nfs_fscache_open_file(struct inode *, struct file *);
  82
  83 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  84 extern int nfs_fscache_release_page(struct page *, gfp_t);
  85
  86 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  87                                        struct inode *, struct page *);
  88 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
  89                                         struct inode *, struct address_space *,
  90                                         struct list_head *, unsigned *);
  91 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
  92
  93 /*
  94  * wait for a page to complete writing to the cache
  95  */
  96 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
  97                                                   struct page *page)
  98 {
  99         if (PageFsCache(page))
 100                 fscache_wait_on_page_write(nfsi->fscache, page);
 101 }
 102
 103 /*
 104  * release the caching state associated with a page if undergoing complete page
 105  * invalidation
 106  */
 107 static inline void nfs_fscache_invalidate_page(struct page *page,
 108                                                struct inode *inode)
 109 {
 110         if (PageFsCache(page))
 111                 __nfs_fscache_invalidate_page(page, inode);
 112 }
 113
 114 /*
 115  * Retrieve a page from an inode data storage object.
 116  */
 117 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 118                                             struct inode *inode,
 119                                             struct page *page)
 120 {
 121         if (NFS_I(inode)->fscache)
 122                 return __nfs_readpage_from_fscache(ctx, inode, page);
 123         return -ENOBUFS;
 124 }
 125
 126 /*
 127  * Retrieve a set of pages from an inode data storage object.
 128  */
 129 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 130                                              struct inode *inode,
 131                                              struct address_space *mapping,
 132                                              struct list_head *pages,
 133                                              unsigned *nr_pages)
 134 {
 135         if (NFS_I(inode)->fscache)
 136                 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 137                                                     nr_pages);
 138         return -ENOBUFS;
 139 }
 140
 141 /*
 142  * Store a page newly fetched from the server in an inode data storage object
 143  * in the cache.
 144  */
 145 static inline void nfs_readpage_to_fscache(struct inode *inode,
 146                                            struct page *page,
 147                                            int sync)
 148 {
 149         if (PageFsCache(page))
 150                 __nfs_readpage_to_fscache(inode, page, sync);
 151 }
 152
 153 /*
 154  * Invalidate the contents of fscache for this inode.  This will not sleep.
 155  */
 156 static inline void nfs_fscache_invalidate(struct inode *inode)
 157 {
 158         fscache_invalidate(NFS_I(inode)->fscache);
 159 }
 160
 161 /*
 162  * Wait for an object to finish being invalidated.
 163  */
 164 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
 165 {
 166         fscache_wait_on_invalidate(NFS_I(inode)->fscache);
 167 }
 168
 169 /*
 170  * indicate the client caching state as readable text
 171  */
 172 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 173 {
 174         if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
 175                 return "yes";
 176         return "no ";
 177 }
 178
 179 #else /* CONFIG_NFS_FSCACHE */
 180 static inline int nfs_fscache_register(void) { return 0; }
 181 static inline void nfs_fscache_unregister(void) {}
 182
 183 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 184 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 185
 186 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 187
 188 static inline void nfs_fscache_init_inode(struct inode *inode) {}
 189 static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 190 static inline void nfs_fscache_open_file(struct inode *inode,
 191                                          struct file *filp) {}
 192
 193 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 194 {
 195         return 1; /* True: may release page */
 196 }
 197 static inline void nfs_fscache_invalidate_page(struct page *page,
 198                                                struct inode *inode) {}
 199 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 200                                                   struct page *page) {}
 201
 202 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 203                                             struct inode *inode,
 204                                             struct page *page)
 205 {
 206         return -ENOBUFS;
 207 }
 208 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 209                                              struct inode *inode,
 210                                              struct address_space *mapping,
 211                                              struct list_head *pages,
 212                                              unsigned *nr_pages)
 213 {
 214         return -ENOBUFS;
 215 }
 216 static inline void nfs_readpage_to_fscache(struct inode *inode,
 217                                            struct page *page, int sync) {}
 218
 219
 220 static inline void nfs_fscache_invalidate(struct inode *inode) {}
 221 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 222
 223 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 224 {
 225         return "no ";
 226 }
 227
 228 #endif /* CONFIG_NFS_FSCACHE */
 229 #endif /* _NFS_FSCACHE_H */