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        s64     mtime_sec;
  66        s64     mtime_nsec;
  67        s64     ctime_sec;
  68        s64     ctime_nsec;
  69        u64     change_attr;
  70};
  71
  72/*
  73 * fscache-index.c
  74 */
  75extern struct fscache_netfs nfs_fscache_netfs;
  76extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  77extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  78extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  79
  80extern int nfs_fscache_register(void);
  81extern void nfs_fscache_unregister(void);
  82
  83/*
  84 * fscache.c
  85 */
  86extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  87extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  88
  89extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  90extern void nfs_fscache_release_super_cookie(struct super_block *);
  91
  92extern void nfs_fscache_init_inode(struct inode *);
  93extern void nfs_fscache_clear_inode(struct inode *);
  94extern void nfs_fscache_open_file(struct inode *, struct file *);
  95
  96extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  97extern int nfs_fscache_release_page(struct page *, gfp_t);
  98
  99extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
 100                                       struct inode *, struct page *);
 101extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
 102                                        struct inode *, struct address_space *,
 103                                        struct list_head *, unsigned *);
 104extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
 105
 106/*
 107 * wait for a page to complete writing to the cache
 108 */
 109static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 110                                                  struct page *page)
 111{
 112        if (PageFsCache(page))
 113                fscache_wait_on_page_write(nfsi->fscache, page);
 114}
 115
 116/*
 117 * release the caching state associated with a page if undergoing complete page
 118 * invalidation
 119 */
 120static inline void nfs_fscache_invalidate_page(struct page *page,
 121                                               struct inode *inode)
 122{
 123        if (PageFsCache(page))
 124                __nfs_fscache_invalidate_page(page, inode);
 125}
 126
 127/*
 128 * Retrieve a page from an inode data storage object.
 129 */
 130static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 131                                            struct inode *inode,
 132                                            struct page *page)
 133{
 134        if (NFS_I(inode)->fscache)
 135                return __nfs_readpage_from_fscache(ctx, inode, page);
 136        return -ENOBUFS;
 137}
 138
 139/*
 140 * Retrieve a set of pages from an inode data storage object.
 141 */
 142static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 143                                             struct inode *inode,
 144                                             struct address_space *mapping,
 145                                             struct list_head *pages,
 146                                             unsigned *nr_pages)
 147{
 148        if (NFS_I(inode)->fscache)
 149                return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 150                                                    nr_pages);
 151        return -ENOBUFS;
 152}
 153
 154/*
 155 * Store a page newly fetched from the server in an inode data storage object
 156 * in the cache.
 157 */
 158static inline void nfs_readpage_to_fscache(struct inode *inode,
 159                                           struct page *page,
 160                                           int sync)
 161{
 162        if (PageFsCache(page))
 163                __nfs_readpage_to_fscache(inode, page, sync);
 164}
 165
 166/*
 167 * Invalidate the contents of fscache for this inode.  This will not sleep.
 168 */
 169static inline void nfs_fscache_invalidate(struct inode *inode)
 170{
 171        fscache_invalidate(NFS_I(inode)->fscache);
 172}
 173
 174/*
 175 * Wait for an object to finish being invalidated.
 176 */
 177static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
 178{
 179        fscache_wait_on_invalidate(NFS_I(inode)->fscache);
 180}
 181
 182/*
 183 * indicate the client caching state as readable text
 184 */
 185static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 186{
 187        if (server->fscache)
 188                return "yes";
 189        return "no ";
 190}
 191
 192#else /* CONFIG_NFS_FSCACHE */
 193static inline int nfs_fscache_register(void) { return 0; }
 194static inline void nfs_fscache_unregister(void) {}
 195
 196static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 197static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 198
 199static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 200
 201static inline void nfs_fscache_init_inode(struct inode *inode) {}
 202static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 203static inline void nfs_fscache_open_file(struct inode *inode,
 204                                         struct file *filp) {}
 205
 206static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 207{
 208        return 1; /* True: may release page */
 209}
 210static inline void nfs_fscache_invalidate_page(struct page *page,
 211                                               struct inode *inode) {}
 212static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 213                                                  struct page *page) {}
 214
 215static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 216                                            struct inode *inode,
 217                                            struct page *page)
 218{
 219        return -ENOBUFS;
 220}
 221static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 222                                             struct inode *inode,
 223                                             struct address_space *mapping,
 224                                             struct list_head *pages,
 225                                             unsigned *nr_pages)
 226{
 227        return -ENOBUFS;
 228}
 229static inline void nfs_readpage_to_fscache(struct inode *inode,
 230                                           struct page *page, int sync) {}
 231
 232
 233static inline void nfs_fscache_invalidate(struct inode *inode) {}
 234static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 235
 236static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 237{
 238        return "no ";
 239}
 240
 241#endif /* CONFIG_NFS_FSCACHE */
 242#endif /* _NFS_FSCACHE_H */
 243