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  * Definition of the auxiliary data attached to NFS inode storage objects
  61  * within the cache.
  62  *
  63  * The contents of this struct are recorded in the on-disk local cache in the
  64  * auxiliary data attached to the data storage object backing an inode.  This
  65  * permits coherency to be managed when a new inode binds to an already extant
  66  * cache object.
  67  */
  68 struct nfs_fscache_inode_auxdata {
  69         struct timespec mtime;
  70         struct timespec ctime;
  71         u64             change_attr;
  72 };
  73
  74 /*
  75  * fscache-index.c
  76  */
  77 extern struct fscache_netfs nfs_fscache_netfs;
  78 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  79 extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  80 extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  81
  82 extern int nfs_fscache_register(void);
  83 extern void nfs_fscache_unregister(void);
  84
  85 /*
  86  * fscache.c
  87  */
  88 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  89 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  90
  91 extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  92 extern void nfs_fscache_release_super_cookie(struct super_block *);
  93
  94 extern void nfs_fscache_init_inode(struct inode *);
  95 extern void nfs_fscache_clear_inode(struct inode *);
  96 extern void nfs_fscache_open_file(struct inode *, struct file *);
  97
  98 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  99 extern int nfs_fscache_release_page(struct page *, gfp_t);
 100
 101 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
 102                                        struct inode *, struct page *);
 103 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
 104                                         struct inode *, struct address_space *,
 105                                         struct list_head *, unsigned *);
 106 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
 107
 108 /*
 109  * wait for a page to complete writing to the cache
 110  */
 111 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 112                                                   struct page *page)
 113 {
 114         if (PageFsCache(page))
 115                 fscache_wait_on_page_write(nfsi->fscache, page);
 116 }
 117
 118 /*
 119  * release the caching state associated with a page if undergoing complete page
 120  * invalidation
 121  */
 122 static inline void nfs_fscache_invalidate_page(struct page *page,
 123                                                struct inode *inode)
 124 {
 125         if (PageFsCache(page))
 126                 __nfs_fscache_invalidate_page(page, inode);
 127 }
 128
 129 /*
 130  * Retrieve a page from an inode data storage object.
 131  */
 132 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 133                                             struct inode *inode,
 134                                             struct page *page)
 135 {
 136         if (NFS_I(inode)->fscache)
 137                 return __nfs_readpage_from_fscache(ctx, inode, page);
 138         return -ENOBUFS;
 139 }
 140
 141 /*
 142  * Retrieve a set of pages from an inode data storage object.
 143  */
 144 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 145                                              struct inode *inode,
 146                                              struct address_space *mapping,
 147                                              struct list_head *pages,
 148                                              unsigned *nr_pages)
 149 {
 150         if (NFS_I(inode)->fscache)
 151                 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 152                                                     nr_pages);
 153         return -ENOBUFS;
 154 }
 155
 156 /*
 157  * Store a page newly fetched from the server in an inode data storage object
 158  * in the cache.
 159  */
 160 static inline void nfs_readpage_to_fscache(struct inode *inode,
 161                                            struct page *page,
 162                                            int sync)
 163 {
 164         if (PageFsCache(page))
 165                 __nfs_readpage_to_fscache(inode, page, sync);
 166 }
 167
 168 /*
 169  * Invalidate the contents of fscache for this inode.  This will not sleep.
 170  */
 171 static inline void nfs_fscache_invalidate(struct inode *inode)
 172 {
 173         fscache_invalidate(NFS_I(inode)->fscache);
 174 }
 175
 176 /*
 177  * Wait for an object to finish being invalidated.
 178  */
 179 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
 180 {
 181         fscache_wait_on_invalidate(NFS_I(inode)->fscache);
 182 }
 183
 184 /*
 185  * indicate the client caching state as readable text
 186  */
 187 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 188 {
 189         if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
 190                 return "yes";
 191         return "no ";
 192 }
 193
 194 #else /* CONFIG_NFS_FSCACHE */
 195 static inline int nfs_fscache_register(void) { return 0; }
 196 static inline void nfs_fscache_unregister(void) {}
 197
 198 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 199 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 200
 201 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 202
 203 static inline void nfs_fscache_init_inode(struct inode *inode) {}
 204 static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 205 static inline void nfs_fscache_open_file(struct inode *inode,
 206                                          struct file *filp) {}
 207
 208 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 209 {
 210         return 1; /* True: may release page */
 211 }
 212 static inline void nfs_fscache_invalidate_page(struct page *page,
 213                                                struct inode *inode) {}
 214 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 215                                                   struct page *page) {}
 216
 217 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 218                                             struct inode *inode,
 219                                             struct page *page)
 220 {
 221         return -ENOBUFS;
 222 }
 223 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 224                                              struct inode *inode,
 225                                              struct address_space *mapping,
 226                                              struct list_head *pages,
 227                                              unsigned *nr_pages)
 228 {
 229         return -ENOBUFS;
 230 }
 231 static inline void nfs_readpage_to_fscache(struct inode *inode,
 232                                            struct page *page, int sync) {}
 233
 234
 235 static inline void nfs_fscache_invalidate(struct inode *inode) {}
 236 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 237
 238 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 239 {
 240         return "no ";
 241 }
 242
 243 #endif /* CONFIG_NFS_FSCACHE */
 244 #endif /* _NFS_FSCACHE_H */