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