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  */
  21 struct 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  */
  64 struct nfs_fscache_inode_auxdata {
  65         struct timespec mtime;
  66         struct timespec ctime;
  67         u64             change_attr;
  68 };
  69
  70 /*
  71  * fscache-index.c
  72  */
  73 extern struct fscache_netfs nfs_fscache_netfs;
  74 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  75 extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  76 extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  77
  78 extern int nfs_fscache_register(void);
  79 extern void nfs_fscache_unregister(void);
  80
  81 /*
  82  * fscache.c
  83  */
  84 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  85 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  86
  87 extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  88 extern void nfs_fscache_release_super_cookie(struct super_block *);
  89
  90 extern void nfs_fscache_init_inode(struct inode *);
  91 extern void nfs_fscache_clear_inode(struct inode *);
  92 extern void nfs_fscache_open_file(struct inode *, struct file *);
  93
  94 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  95 extern int nfs_fscache_release_page(struct page *, gfp_t);
  96
  97 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
  98                                        struct inode *, struct page *);
  99 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
 100                                         struct inode *, struct address_space *,
 101                                         struct list_head *, unsigned *);
 102 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
 103
 104 /*
 105  * wait for a page to complete writing to the cache
 106  */
 107 static 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  */
 118 static 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  */
 128 static 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  */
 140 static 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  */
 156 static 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  */
 167 static 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  */
 175 static 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  */
 183 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 184 {
 185         if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
 186                 return "yes";
 187         return "no ";
 188 }
 189
 190 #else /* CONFIG_NFS_FSCACHE */
 191 static inline int nfs_fscache_register(void) { return 0; }
 192 static inline void nfs_fscache_unregister(void) {}
 193
 194 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 195 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 196
 197 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 198
 199 static inline void nfs_fscache_init_inode(struct inode *inode) {}
 200 static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 201 static inline void nfs_fscache_open_file(struct inode *inode,
 202                                          struct file *filp) {}
 203
 204 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 205 {
 206         return 1; /* True: may release page */
 207 }
 208 static inline void nfs_fscache_invalidate_page(struct page *page,
 209                                                struct inode *inode) {}
 210 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 211                                                   struct page *page) {}
 212
 213 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 214                                             struct inode *inode,
 215                                             struct page *page)
 216 {
 217         return -ENOBUFS;
 218 }
 219 static 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 }
 227 static inline void nfs_readpage_to_fscache(struct inode *inode,
 228                                            struct page *page, int sync) {}
 229
 230
 231 static inline void nfs_fscache_invalidate(struct inode *inode) {}
 232 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 233
 234 static 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 */