LXR linux/fs/nfs/fscache.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/* NFS filesystem cache interface definitions
   3 *
   4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#ifndef _NFS_FSCACHE_H
   9#define _NFS_FSCACHE_H
  10
  11#include <linux/nfs_fs.h>
  12#include <linux/nfs_mount.h>
  13#include <linux/nfs4_mount.h>
  14#include <linux/fscache.h>
  15
  16#ifdef CONFIG_NFS_FSCACHE
  17
  18/*
  19 * set of NFS FS-Cache objects that form a superblock key
  20 */
  21struct nfs_fscache_key {
  22        struct rb_node          node;
  23        struct nfs_client       *nfs_client;    /* the server */
  24
  25        /* the elements of the unique key - as used by nfs_compare_super() and
  26         * nfs_compare_mount_options() to distinguish superblocks */
  27        struct {
  28                struct {
  29                        unsigned long   s_flags;        /* various flags
  30                                                         * (& NFS_MS_MASK) */
  31                } super;
  32
  33                struct {
  34                        struct nfs_fsid fsid;
  35                        int             flags;
  36                        unsigned int    rsize;          /* read size */
  37                        unsigned int    wsize;          /* write size */
  38                        unsigned int    acregmin;       /* attr cache timeouts */
  39                        unsigned int    acregmax;
  40                        unsigned int    acdirmin;
  41                        unsigned int    acdirmax;
  42                } nfs_server;
  43
  44                struct {
  45                        rpc_authflavor_t au_flavor;
  46                } rpc_auth;
  47
  48                /* uniquifier - can be used if nfs_server.flags includes
  49                 * NFS_MOUNT_UNSHARED  */
  50                u8 uniq_len;
  51                char uniquifier[0];
  52        } key;
  53};
  54
  55/*
  56 * Definition of the auxiliary data attached to NFS inode storage objects
  57 * within the cache.
  58 *
  59 * The contents of this struct are recorded in the on-disk local cache in the
  60 * auxiliary data attached to the data storage object backing an inode.  This
  61 * permits coherency to be managed when a new inode binds to an already extant
  62 * cache object.
  63 */
  64struct nfs_fscache_inode_auxdata {
  65        struct timespec mtime;
  66        struct timespec ctime;
  67        u64             change_attr;
  68};
  69
  70/*
  71 * fscache-index.c
  72 */
  73extern struct fscache_netfs nfs_fscache_netfs;
  74extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  75extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  76extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  77
  78extern int nfs_fscache_register(void);
  79extern void nfs_fscache_unregister(void);
  80
  81/*
  82 * fscache.c
  83 */
  84extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  85extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  86
  87extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  88extern void nfs_fscache_release_super_cookie(struct super_block *);
  89
  90extern void nfs_fscache_init_inode(struct inode *);
  91extern void nfs_fscache_clear_inode(struct inode *);
  92extern void nfs_fscache_open_file(struct inode *, struct file *);
  93
  94extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  95extern int nfs_fscache_release_page(struct page *, gfp_t);
  96
  97extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  98                                       struct inode *, struct page *);
  99extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
 100                                        struct inode *, struct address_space *,
 101                                        struct list_head *, unsigned *);
 102extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
 103
 104/*
 105 * wait for a page to complete writing to the cache
 106 */
 107static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 108                                                  struct page *page)
 109{
 110        if (PageFsCache(page))
 111                fscache_wait_on_page_write(nfsi->fscache, page);
 112}
 113
 114/*
 115 * release the caching state associated with a page if undergoing complete page
 116 * invalidation
 117 */
 118static inline void nfs_fscache_invalidate_page(struct page *page,
 119                                               struct inode *inode)
 120{
 121        if (PageFsCache(page))
 122                __nfs_fscache_invalidate_page(page, inode);
 123}
 124
 125/*
 126 * Retrieve a page from an inode data storage object.
 127 */
 128static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 129                                            struct inode *inode,
 130                                            struct page *page)
 131{
 132        if (NFS_I(inode)->fscache)
 133                return __nfs_readpage_from_fscache(ctx, inode, page);
 134        return -ENOBUFS;
 135}
 136
 137/*
 138 * Retrieve a set of pages from an inode data storage object.
 139 */
 140static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 141                                             struct inode *inode,
 142                                             struct address_space *mapping,
 143                                             struct list_head *pages,
 144                                             unsigned *nr_pages)
 145{
 146        if (NFS_I(inode)->fscache)
 147                return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 148                                                    nr_pages);
 149        return -ENOBUFS;
 150}
 151
 152/*
 153 * Store a page newly fetched from the server in an inode data storage object
 154 * in the cache.
 155 */
 156static inline void nfs_readpage_to_fscache(struct inode *inode,
 157                                           struct page *page,
 158                                           int sync)
 159{
 160        if (PageFsCache(page))
 161                __nfs_readpage_to_fscache(inode, page, sync);
 162}
 163
 164/*
 165 * Invalidate the contents of fscache for this inode.  This will not sleep.
 166 */
 167static inline void nfs_fscache_invalidate(struct inode *inode)
 168{
 169        fscache_invalidate(NFS_I(inode)->fscache);
 170}
 171
 172/*
 173 * Wait for an object to finish being invalidated.
 174 */
 175static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
 176{
 177        fscache_wait_on_invalidate(NFS_I(inode)->fscache);
 178}
 179
 180/*
 181 * indicate the client caching state as readable text
 182 */
 183static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 184{
 185        if (server->fscache)
 186                return "yes";
 187        return "no ";
 188}
 189
 190#else /* CONFIG_NFS_FSCACHE */
 191static inline int nfs_fscache_register(void) { return 0; }
 192static inline void nfs_fscache_unregister(void) {}
 193
 194static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 195static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 196
 197static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 198
 199static inline void nfs_fscache_init_inode(struct inode *inode) {}
 200static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 201static inline void nfs_fscache_open_file(struct inode *inode,
 202                                         struct file *filp) {}
 203
 204static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 205{
 206        return 1; /* True: may release page */
 207}
 208static inline void nfs_fscache_invalidate_page(struct page *page,
 209                                               struct inode *inode) {}
 210static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 211                                                  struct page *page) {}
 212
 213static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 214                                            struct inode *inode,
 215                                            struct page *page)
 216{
 217        return -ENOBUFS;
 218}
 219static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 220                                             struct inode *inode,
 221                                             struct address_space *mapping,
 222                                             struct list_head *pages,
 223                                             unsigned *nr_pages)
 224{
 225        return -ENOBUFS;
 226}
 227static inline void nfs_readpage_to_fscache(struct inode *inode,
 228                                           struct page *page, int sync) {}
 229
 230
 231static inline void nfs_fscache_invalidate(struct inode *inode) {}
 232static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 233
 234static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 235{
 236        return "no ";
 237}
 238
 239#endif /* CONFIG_NFS_FSCACHE */
 240#endif /* _NFS_FSCACHE_H */
 241