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 *,
  77                                         const char *,
  78                                         struct nfs_clone_mount *);
  79extern void nfs_fscache_release_super_cookie(struct super_block *);
  80
  81extern void nfs_fscache_init_inode_cookie(struct inode *);
  82extern void nfs_fscache_release_inode_cookie(struct inode *);
  83extern void nfs_fscache_zap_inode_cookie(struct inode *);
  84extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);
  85extern void nfs_fscache_reset_inode_cookie(struct inode *);
  86
  87extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  88extern int nfs_fscache_release_page(struct page *, gfp_t);
  89
  90extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  91                                       struct inode *, struct page *);
  92extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
  93                                        struct inode *, struct address_space *,
  94                                        struct list_head *, unsigned *);
  95extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
  96
  97/*
  98 * wait for a page to complete writing to the cache
  99 */
 100static 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 */
 111static 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 */
 121static 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 */
 133static 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 */
 149static 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 */
 160static 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 */
 169static inline int nfs_fscache_register(void) { return 0; }
 170static inline void nfs_fscache_unregister(void) {}
 171
 172static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 173static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 174
 175static inline void nfs_fscache_get_super_cookie(
 176        struct super_block *sb,
 177        const char *uniq,
 178        struct nfs_clone_mount *mntdata)
 179{
 180}
 181static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 182
 183static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
 184static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
 185static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
 186static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
 187                                                struct file *filp) {}
 188static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
 189
 190static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 191{
 192        return 1; /* True: may release page */
 193}
 194static inline void nfs_fscache_invalidate_page(struct page *page,
 195                                               struct inode *inode) {}
 196static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 197                                                  struct page *page) {}
 198
 199static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 200                                            struct inode *inode,
 201                                            struct page *page)
 202{
 203        return -ENOBUFS;
 204}
 205static 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}
 213static inline void nfs_readpage_to_fscache(struct inode *inode,
 214                                           struct page *page, int sync) {}
 215
 216static 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 */
 223