LXR linux/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 */
  25struct 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 */
  62extern struct fscache_netfs nfs_fscache_netfs;
  63extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  64extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  65extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  66
  67extern int nfs_fscache_register(void);
  68extern void nfs_fscache_unregister(void);
  69
  70/*
  71 * fscache.c
  72 */
  73extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  74extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  75
  76extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  77extern void nfs_fscache_release_super_cookie(struct super_block *);
  78
  79extern void nfs_fscache_init_inode(struct inode *);
  80extern void nfs_fscache_clear_inode(struct inode *);
  81extern void nfs_fscache_open_file(struct inode *, struct file *);
  82
  83extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  84extern int nfs_fscache_release_page(struct page *, gfp_t);
  85
  86extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  87                                       struct inode *, struct page *);
  88extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
  89                                        struct inode *, struct address_space *,
  90                                        struct list_head *, unsigned *);
  91extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
  92
  93/*
  94 * wait for a page to complete writing to the cache
  95 */
  96static 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 */
 107static 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 */
 117static 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 */
 129static 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 */
 145static 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 */
 156static 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 */
 164static 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 */
 172static 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 */
 180static inline int nfs_fscache_register(void) { return 0; }
 181static inline void nfs_fscache_unregister(void) {}
 182
 183static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 184static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 185
 186static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 187
 188static inline void nfs_fscache_init_inode(struct inode *inode) {}
 189static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 190static inline void nfs_fscache_open_file(struct inode *inode,
 191                                         struct file *filp) {}
 192
 193static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 194{
 195        return 1; /* True: may release page */
 196}
 197static inline void nfs_fscache_invalidate_page(struct page *page,
 198                                               struct inode *inode) {}
 199static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 200                                                  struct page *page) {}
 201
 202static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 203                                            struct inode *inode,
 204                                            struct page *page)
 205{
 206        return -ENOBUFS;
 207}
 208static 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}
 216static inline void nfs_readpage_to_fscache(struct inode *inode,
 217                                           struct page *page, int sync) {}
 218
 219
 220static inline void nfs_fscache_invalidate(struct inode *inode) {}
 221static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 222
 223static 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 */
 230