fs/nfs/internal.h

   1 /*
   2  * NFS internal definitions
   3  */
   4
   5 #include "nfs4_fs.h"
   6 #include <linux/mount.h>
   7 #include <linux/security.h>
   8
   9 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
  10
  11 struct nfs_string;
  12
  13 /* Maximum number of readahead requests
  14  * FIXME: this should really be a sysctl so that users may tune it to suit
  15  *        their needs. People that do NFS over a slow network, might for
  16  *        instance want to reduce it to something closer to 1 for improved
  17  *        interactive response.
  18  */
  19 #define NFS_MAX_READAHEAD       (RPC_DEF_SLOT_TABLE - 1)
  20
  21 static inline void nfs_attr_check_mountpoint(struct super_block *parent, struct nfs_fattr *fattr)
  22 {
  23         if (!nfs_fsid_equal(&NFS_SB(parent)->fsid, &fattr->fsid))
  24                 fattr->valid |= NFS_ATTR_FATTR_MOUNTPOINT;
  25 }
  26
  27 static inline int nfs_attr_use_mounted_on_fileid(struct nfs_fattr *fattr)
  28 {
  29         if (((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) == 0) ||
  30             (((fattr->valid & NFS_ATTR_FATTR_MOUNTPOINT) == 0) &&
  31              ((fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) == 0)))
  32                 return 0;
  33
  34         fattr->fileid = fattr->mounted_on_fileid;
  35         return 1;
  36 }
  37
  38 struct nfs_clone_mount {
  39         const struct super_block *sb;
  40         const struct dentry *dentry;
  41         struct nfs_fh *fh;
  42         struct nfs_fattr *fattr;
  43         char *hostname;
  44         char *mnt_path;
  45         struct sockaddr *addr;
  46         size_t addrlen;
  47         rpc_authflavor_t authflavor;
  48 };
  49
  50 /*
  51  * Note: RFC 1813 doesn't limit the number of auth flavors that
  52  * a server can return, so make something up.
  53  */
  54 #define NFS_MAX_SECFLAVORS      (12)
  55
  56 /*
  57  * Value used if the user did not specify a port value.
  58  */
  59 #define NFS_UNSPEC_PORT         (-1)
  60
  61 /*
  62  * Maximum number of pages that readdir can use for creating
  63  * a vmapped array of pages.
  64  */
  65 #define NFS_MAX_READDIR_PAGES 8
  66
  67 struct nfs_client_initdata {
  68         unsigned long init_flags;
  69         const char *hostname;
  70         const struct sockaddr *addr;
  71         size_t addrlen;
  72         struct nfs_subversion *nfs_mod;
  73         int proto;
  74         u32 minorversion;
  75         struct net *net;
  76 };
  77
  78 /*
  79  * In-kernel mount arguments
  80  */
  81 struct nfs_parsed_mount_data {
  82         int                     flags;
  83         unsigned int            rsize, wsize;
  84         unsigned int            timeo, retrans;
  85         unsigned int            acregmin, acregmax,
  86                                 acdirmin, acdirmax;
  87         unsigned int            namlen;
  88         unsigned int            options;
  89         unsigned int            bsize;
  90         unsigned int            auth_flavor_len;
  91         rpc_authflavor_t        auth_flavors[1];
  92         char                    *client_address;
  93         unsigned int            version;
  94         unsigned int            minorversion;
  95         char                    *fscache_uniq;
  96         bool                    need_mount;
  97
  98         struct {
  99                 struct sockaddr_storage address;
 100                 size_t                  addrlen;
 101                 char                    *hostname;
 102                 u32                     version;
 103                 int                     port;
 104                 unsigned short          protocol;
 105         } mount_server;
 106
 107         struct {
 108                 struct sockaddr_storage address;
 109                 size_t                  addrlen;
 110                 char                    *hostname;
 111                 char                    *export_path;
 112                 int                     port;
 113                 unsigned short          protocol;
 114         } nfs_server;
 115
 116         struct security_mnt_opts lsm_opts;
 117         struct net              *net;
 118 };
 119
 120 /* mount_clnt.c */
 121 struct nfs_mount_request {
 122         struct sockaddr         *sap;
 123         size_t                  salen;
 124         char                    *hostname;
 125         char                    *dirpath;
 126         u32                     version;
 127         unsigned short          protocol;
 128         struct nfs_fh           *fh;
 129         int                     noresvport;
 130         unsigned int            *auth_flav_len;
 131         rpc_authflavor_t        *auth_flavs;
 132         struct net              *net;
 133 };
 134
 135 struct nfs_mount_info {
 136         void (*fill_super)(struct super_block *, struct nfs_mount_info *);
 137         int (*set_security)(struct super_block *, struct dentry *, struct nfs_mount_info *);
 138         struct nfs_parsed_mount_data *parsed;
 139         struct nfs_clone_mount *cloned;
 140         struct nfs_fh *mntfh;
 141 };
 142
 143 extern int nfs_mount(struct nfs_mount_request *info);
 144 extern void nfs_umount(const struct nfs_mount_request *info);
 145
 146 /* client.c */
 147 extern const struct rpc_program nfs_program;
 148 extern void nfs_clients_init(struct net *net);
 149 extern struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *);
 150 int nfs_create_rpc_client(struct nfs_client *, const struct rpc_timeout *, rpc_authflavor_t);
 151 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *,
 152                                   const struct rpc_timeout *, const char *,
 153                                   rpc_authflavor_t);
 154 int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *, struct nfs_fattr *);
 155 void nfs_server_insert_lists(struct nfs_server *);
 156 void nfs_init_timeout_values(struct rpc_timeout *, int, unsigned int, unsigned int);
 157 int nfs_init_server_rpcclient(struct nfs_server *, const struct rpc_timeout *t,
 158                 rpc_authflavor_t);
 159 struct nfs_server *nfs_alloc_server(void);
 160 void nfs_server_copy_userdata(struct nfs_server *, struct nfs_server *);
 161
 162 extern void nfs_cleanup_cb_ident_idr(struct net *);
 163 extern void nfs_put_client(struct nfs_client *);
 164 extern void nfs_free_client(struct nfs_client *);
 165 extern struct nfs_client *nfs4_find_client_ident(struct net *, int);
 166 extern struct nfs_client *
 167 nfs4_find_client_sessionid(struct net *, const struct sockaddr *,
 168                                 struct nfs4_sessionid *);
 169 extern struct nfs_server *nfs_create_server(struct nfs_mount_info *,
 170                                         struct nfs_subversion *);
 171 extern struct nfs_server *nfs4_create_server(
 172                                         struct nfs_mount_info *,
 173                                         struct nfs_subversion *);
 174 extern struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *,
 175                                                       struct nfs_fh *);
 176 extern void nfs_free_server(struct nfs_server *server);
 177 extern struct nfs_server *nfs_clone_server(struct nfs_server *,
 178                                            struct nfs_fh *,
 179                                            struct nfs_fattr *,
 180                                            rpc_authflavor_t);
 181 extern int nfs_wait_client_init_complete(const struct nfs_client *clp);
 182 extern void nfs_mark_client_ready(struct nfs_client *clp, int state);
 183 extern struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,
 184                                              const struct sockaddr *ds_addr,
 185                                              int ds_addrlen, int ds_proto,
 186                                              unsigned int ds_timeo,
 187                                              unsigned int ds_retrans);
 188 #ifdef CONFIG_PROC_FS
 189 extern int __init nfs_fs_proc_init(void);
 190 extern void nfs_fs_proc_exit(void);
 191 #else
 192 static inline int nfs_fs_proc_init(void)
 193 {
 194         return 0;
 195 }
 196 static inline void nfs_fs_proc_exit(void)
 197 {
 198 }
 199 #endif
 200
 201 #ifdef CONFIG_NFS_V4_1
 202 int nfs_sockaddr_match_ipaddr(const struct sockaddr *, const struct sockaddr *);
 203 #endif
 204
 205 /* nfs3client.c */
 206 #if IS_ENABLED(CONFIG_NFS_V3)
 207 struct nfs_server *nfs3_create_server(struct nfs_mount_info *, struct nfs_subversion *);
 208 struct nfs_server *nfs3_clone_server(struct nfs_server *, struct nfs_fh *,
 209                                      struct nfs_fattr *, rpc_authflavor_t);
 210 #endif
 211
 212 /* callback_xdr.c */
 213 extern struct svc_version nfs4_callback_version1;
 214 extern struct svc_version nfs4_callback_version4;
 215
 216 struct nfs_pageio_descriptor;
 217 /* pagelist.c */
 218 extern int __init nfs_init_nfspagecache(void);
 219 extern void nfs_destroy_nfspagecache(void);
 220 extern int __init nfs_init_readpagecache(void);
 221 extern void nfs_destroy_readpagecache(void);
 222 extern int __init nfs_init_writepagecache(void);
 223 extern void nfs_destroy_writepagecache(void);
 224
 225 extern int __init nfs_init_directcache(void);
 226 extern void nfs_destroy_directcache(void);
 227 extern bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount);
 228 extern void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
 229                               struct nfs_pgio_header *hdr,
 230                               void (*release)(struct nfs_pgio_header *hdr));
 231 void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos);
 232
 233 /* nfs2xdr.c */
 234 extern struct rpc_procinfo nfs_procedures[];
 235 extern int nfs2_decode_dirent(struct xdr_stream *,
 236                                 struct nfs_entry *, int);
 237
 238 /* nfs3xdr.c */
 239 extern struct rpc_procinfo nfs3_procedures[];
 240 extern int nfs3_decode_dirent(struct xdr_stream *,
 241                                 struct nfs_entry *, int);
 242
 243 /* nfs4xdr.c */
 244 #if IS_ENABLED(CONFIG_NFS_V4)
 245 extern int nfs4_decode_dirent(struct xdr_stream *,
 246                                 struct nfs_entry *, int);
 247 #endif
 248 #ifdef CONFIG_NFS_V4_1
 249 extern const u32 nfs41_maxread_overhead;
 250 extern const u32 nfs41_maxwrite_overhead;
 251 #endif
 252
 253 /* nfs4proc.c */
 254 #if IS_ENABLED(CONFIG_NFS_V4)
 255 extern struct rpc_procinfo nfs4_procedures[];
 256 #endif
 257
 258 /* proc.c */
 259 void nfs_close_context(struct nfs_open_context *ctx, int is_sync);
 260 extern struct nfs_client *nfs_init_client(struct nfs_client *clp,
 261                            const struct rpc_timeout *timeparms,
 262                            const char *ip_addr, rpc_authflavor_t authflavour);
 263
 264 /* dir.c */
 265 extern int nfs_access_cache_shrinker(struct shrinker *shrink,
 266                                         struct shrink_control *sc);
 267 struct dentry *nfs_lookup(struct inode *, struct dentry *, unsigned int);
 268 int nfs_create(struct inode *, struct dentry *, umode_t, bool);
 269 int nfs_mkdir(struct inode *, struct dentry *, umode_t);
 270 int nfs_rmdir(struct inode *, struct dentry *);
 271 int nfs_unlink(struct inode *, struct dentry *);
 272 int nfs_symlink(struct inode *, struct dentry *, const char *);
 273 int nfs_link(struct dentry *, struct inode *, struct dentry *);
 274 int nfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
 275 int nfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 276
 277 /* file.c */
 278 int nfs_file_fsync_commit(struct file *, loff_t, loff_t, int);
 279 loff_t nfs_file_llseek(struct file *, loff_t, int);
 280 int nfs_file_flush(struct file *, fl_owner_t);
 281 ssize_t nfs_file_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 282 ssize_t nfs_file_splice_read(struct file *, loff_t *, struct pipe_inode_info *,
 283                              size_t, unsigned int);
 284 int nfs_file_mmap(struct file *, struct vm_area_struct *);
 285 ssize_t nfs_file_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 286 int nfs_file_release(struct inode *, struct file *);
 287 int nfs_lock(struct file *, int, struct file_lock *);
 288 int nfs_flock(struct file *, int, struct file_lock *);
 289 ssize_t nfs_file_splice_write(struct pipe_inode_info *, struct file *, loff_t *,
 290                               size_t, unsigned int);
 291 int nfs_check_flags(int);
 292 int nfs_setlease(struct file *, long, struct file_lock **);
 293
 294 /* inode.c */
 295 extern struct workqueue_struct *nfsiod_workqueue;
 296 extern struct inode *nfs_alloc_inode(struct super_block *sb);
 297 extern void nfs_destroy_inode(struct inode *);
 298 extern int nfs_write_inode(struct inode *, struct writeback_control *);
 299 extern int nfs_drop_inode(struct inode *);
 300 extern void nfs_clear_inode(struct inode *);
 301 extern void nfs_evict_inode(struct inode *);
 302 void nfs_zap_acl_cache(struct inode *inode);
 303 extern int nfs_wait_bit_killable(void *word);
 304
 305 /* super.c */
 306 extern const struct super_operations nfs_sops;
 307 extern struct file_system_type nfs_fs_type;
 308 extern struct file_system_type nfs_xdev_fs_type;
 309 #if IS_ENABLED(CONFIG_NFS_V4)
 310 extern struct file_system_type nfs4_xdev_fs_type;
 311 extern struct file_system_type nfs4_referral_fs_type;
 312 #endif
 313 struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
 314                         struct nfs_subversion *);
 315 void nfs_initialise_sb(struct super_block *);
 316 int nfs_set_sb_security(struct super_block *, struct dentry *, struct nfs_mount_info *);
 317 int nfs_clone_sb_security(struct super_block *, struct dentry *, struct nfs_mount_info *);
 318 struct dentry *nfs_fs_mount_common(struct nfs_server *, int, const char *,
 319                                    struct nfs_mount_info *, struct nfs_subversion *);
 320 struct dentry *nfs_fs_mount(struct file_system_type *, int, const char *, void *);
 321 struct dentry * nfs_xdev_mount_common(struct file_system_type *, int,
 322                 const char *, struct nfs_mount_info *);
 323 void nfs_kill_super(struct super_block *);
 324 void nfs_fill_super(struct super_block *, struct nfs_mount_info *);
 325
 326 extern struct rpc_stat nfs_rpcstat;
 327
 328 extern int __init register_nfs_fs(void);
 329 extern void __exit unregister_nfs_fs(void);
 330 extern void nfs_sb_active(struct super_block *sb);
 331 extern void nfs_sb_deactive(struct super_block *sb);
 332
 333 /* namespace.c */
 334 #define NFS_PATH_CANONICAL 1
 335 extern char *nfs_path(char **p, struct dentry *dentry,
 336                       char *buffer, ssize_t buflen, unsigned flags);
 337 extern struct vfsmount *nfs_d_automount(struct path *path);
 338 struct vfsmount *nfs_submount(struct nfs_server *, struct dentry *,
 339                               struct nfs_fh *, struct nfs_fattr *);
 340 struct vfsmount *nfs_do_submount(struct dentry *, struct nfs_fh *,
 341                                  struct nfs_fattr *, rpc_authflavor_t);
 342
 343 /* getroot.c */
 344 extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *,
 345                                    const char *);
 346 #if IS_ENABLED(CONFIG_NFS_V4)
 347 extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *,
 348                                     const char *);
 349
 350 extern int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh);
 351 #endif
 352
 353 struct nfs_pgio_completion_ops;
 354 /* read.c */
 355 extern struct nfs_read_header *nfs_readhdr_alloc(void);
 356 extern void nfs_readhdr_free(struct nfs_pgio_header *hdr);
 357 extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
 358                         struct inode *inode,
 359                         const struct nfs_pgio_completion_ops *compl_ops);
 360 extern int nfs_initiate_read(struct rpc_clnt *clnt,
 361                              struct nfs_read_data *data,
 362                              const struct rpc_call_ops *call_ops, int flags);
 363 extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
 364 extern int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
 365                               struct nfs_pgio_header *hdr);
 366 extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);
 367 extern void nfs_readdata_release(struct nfs_read_data *rdata);
 368
 369 /* super.c */
 370 void nfs_clone_super(struct super_block *, struct nfs_mount_info *);
 371 void nfs_umount_begin(struct super_block *);
 372 int  nfs_statfs(struct dentry *, struct kstatfs *);
 373 int  nfs_show_options(struct seq_file *, struct dentry *);
 374 int  nfs_show_devname(struct seq_file *, struct dentry *);
 375 int  nfs_show_path(struct seq_file *, struct dentry *);
 376 int  nfs_show_stats(struct seq_file *, struct dentry *);
 377 void nfs_put_super(struct super_block *);
 378 int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 379
 380 /* write.c */
 381 extern void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 382                         struct inode *inode, int ioflags,
 383                         const struct nfs_pgio_completion_ops *compl_ops);
 384 extern struct nfs_write_header *nfs_writehdr_alloc(void);
 385 extern void nfs_writehdr_free(struct nfs_pgio_header *hdr);
 386 extern int nfs_generic_flush(struct nfs_pageio_descriptor *desc,
 387                              struct nfs_pgio_header *hdr);
 388 extern void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio);
 389 extern void nfs_writedata_release(struct nfs_write_data *wdata);
 390 extern void nfs_commit_free(struct nfs_commit_data *p);
 391 extern int nfs_initiate_write(struct rpc_clnt *clnt,
 392                               struct nfs_write_data *data,
 393                               const struct rpc_call_ops *call_ops,
 394                               int how, int flags);
 395 extern void nfs_write_prepare(struct rpc_task *task, void *calldata);
 396 extern void nfs_commit_prepare(struct rpc_task *task, void *calldata);
 397 extern int nfs_initiate_commit(struct rpc_clnt *clnt,
 398                                struct nfs_commit_data *data,
 399                                const struct rpc_call_ops *call_ops,
 400                                int how, int flags);
 401 extern void nfs_init_commit(struct nfs_commit_data *data,
 402                             struct list_head *head,
 403                             struct pnfs_layout_segment *lseg,
 404                             struct nfs_commit_info *cinfo);
 405 int nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
 406                          struct nfs_commit_info *cinfo, int max);
 407 int nfs_scan_commit(struct inode *inode, struct list_head *dst,
 408                     struct nfs_commit_info *cinfo);
 409 void nfs_mark_request_commit(struct nfs_page *req,
 410                              struct pnfs_layout_segment *lseg,
 411                              struct nfs_commit_info *cinfo);
 412 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
 413                             int how, struct nfs_commit_info *cinfo);
 414 void nfs_retry_commit(struct list_head *page_list,
 415                       struct pnfs_layout_segment *lseg,
 416                       struct nfs_commit_info *cinfo);
 417 void nfs_commitdata_release(struct nfs_commit_data *data);
 418 void nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
 419                                  struct nfs_commit_info *cinfo);
 420 void nfs_request_remove_commit_list(struct nfs_page *req,
 421                                     struct nfs_commit_info *cinfo);
 422 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 423                     struct inode *inode,
 424                     struct nfs_direct_req *dreq);
 425
 426 #ifdef CONFIG_MIGRATION
 427 extern int nfs_migrate_page(struct address_space *,
 428                 struct page *, struct page *, enum migrate_mode);
 429 #else
 430 #define nfs_migrate_page NULL
 431 #endif
 432
 433 /* direct.c */
 434 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
 435                               struct nfs_direct_req *dreq);
 436 static inline void nfs_inode_dio_wait(struct inode *inode)
 437 {
 438         inode_dio_wait(inode);
 439 }
 440 extern ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq);
 441
 442 /* nfs4proc.c */
 443 extern void __nfs4_read_done_cb(struct nfs_read_data *);
 444 extern struct nfs_client *nfs4_init_client(struct nfs_client *clp,
 445                             const struct rpc_timeout *timeparms,
 446                             const char *ip_addr,
 447                             rpc_authflavor_t authflavour);
 448 extern int nfs40_walk_client_list(struct nfs_client *clp,
 449                                 struct nfs_client **result,
 450                                 struct rpc_cred *cred);
 451 extern int nfs41_walk_client_list(struct nfs_client *clp,
 452                                 struct nfs_client **result,
 453                                 struct rpc_cred *cred);
 454
 455 /*
 456  * Determine the device name as a string
 457  */
 458 static inline char *nfs_devname(struct dentry *dentry,
 459                                 char *buffer, ssize_t buflen)
 460 {
 461         char *dummy;
 462         return nfs_path(&dummy, dentry, buffer, buflen, NFS_PATH_CANONICAL);
 463 }
 464
 465 /*
 466  * Determine the actual block size (and log2 thereof)
 467  */
 468 static inline
 469 unsigned long nfs_block_bits(unsigned long bsize, unsigned char *nrbitsp)
 470 {
 471         /* make sure blocksize is a power of two */
 472         if ((bsize & (bsize - 1)) || nrbitsp) {
 473                 unsigned char   nrbits;
 474
 475                 for (nrbits = 31; nrbits && !(bsize & (1 << nrbits)); nrbits--)
 476                         ;
 477                 bsize = 1 << nrbits;
 478                 if (nrbitsp)
 479                         *nrbitsp = nrbits;
 480         }
 481
 482         return bsize;
 483 }
 484
 485 /*
 486  * Calculate the number of 512byte blocks used.
 487  */
 488 static inline blkcnt_t nfs_calc_block_size(u64 tsize)
 489 {
 490         blkcnt_t used = (tsize + 511) >> 9;
 491         return (used > ULONG_MAX) ? ULONG_MAX : used;
 492 }
 493
 494 /*
 495  * Compute and set NFS server blocksize
 496  */
 497 static inline
 498 unsigned long nfs_block_size(unsigned long bsize, unsigned char *nrbitsp)
 499 {
 500         if (bsize < NFS_MIN_FILE_IO_SIZE)
 501                 bsize = NFS_DEF_FILE_IO_SIZE;
 502         else if (bsize >= NFS_MAX_FILE_IO_SIZE)
 503                 bsize = NFS_MAX_FILE_IO_SIZE;
 504
 505         return nfs_block_bits(bsize, nrbitsp);
 506 }
 507
 508 /*
 509  * Determine the maximum file size for a superblock
 510  */
 511 static inline
 512 void nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize)
 513 {
 514         sb->s_maxbytes = (loff_t)maxfilesize;
 515         if (sb->s_maxbytes > MAX_LFS_FILESIZE || sb->s_maxbytes <= 0)
 516                 sb->s_maxbytes = MAX_LFS_FILESIZE;
 517 }
 518
 519 /*
 520  * Determine the number of bytes of data the page contains
 521  */
 522 static inline
 523 unsigned int nfs_page_length(struct page *page)
 524 {
 525         loff_t i_size = i_size_read(page_file_mapping(page)->host);
 526
 527         if (i_size > 0) {
 528                 pgoff_t page_index = page_file_index(page);
 529                 pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 530                 if (page_index < end_index)
 531                         return PAGE_CACHE_SIZE;
 532                 if (page_index == end_index)
 533                         return ((i_size - 1) & ~PAGE_CACHE_MASK) + 1;
 534         }
 535         return 0;
 536 }
 537
 538 /*
 539  * Convert a umode to a dirent->d_type
 540  */
 541 static inline
 542 unsigned char nfs_umode_to_dtype(umode_t mode)
 543 {
 544         return (mode >> 12) & 15;
 545 }
 546
 547 /*
 548  * Determine the number of pages in an array of length 'len' and
 549  * with a base offset of 'base'
 550  */
 551 static inline
 552 unsigned int nfs_page_array_len(unsigned int base, size_t len)
 553 {
 554         return ((unsigned long)len + (unsigned long)base +
 555                 PAGE_SIZE - 1) >> PAGE_SHIFT;
 556 }
 557
 558 /*
 559  * Convert a struct timespec into a 64-bit change attribute
 560  *
 561  * This does approximately the same thing as timespec_to_ns(),
 562  * but for calculation efficiency, we multiply the seconds by
 563  * 1024*1024*1024.
 564  */
 565 static inline
 566 u64 nfs_timespec_to_change_attr(const struct timespec *ts)
 567 {
 568         return ((u64)ts->tv_sec << 30) + ts->tv_nsec;
 569 }