linux/fs/nfs/internal.h
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   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
  11struct 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
  21static 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
  27static 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
  38struct 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
  67struct 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 */
  81struct 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 */
 121struct 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
 135struct 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
 143extern int nfs_mount(struct nfs_mount_request *info);
 144extern void nfs_umount(const struct nfs_mount_request *info);
 145
 146/* client.c */
 147extern const struct rpc_program nfs_program;
 148extern void nfs_clients_init(struct net *net);
 149extern struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *);
 150int nfs_create_rpc_client(struct nfs_client *, const struct rpc_timeout *, rpc_authflavor_t);
 151struct nfs_client *nfs_get_client(const struct nfs_client_initdata *,
 152                                  const struct rpc_timeout *, const char *,
 153                                  rpc_authflavor_t);
 154int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *, struct nfs_fattr *);
 155void nfs_server_insert_lists(struct nfs_server *);
 156void nfs_init_timeout_values(struct rpc_timeout *, int, unsigned int, unsigned int);
 157int nfs_init_server_rpcclient(struct nfs_server *, const struct rpc_timeout *t,
 158                rpc_authflavor_t);
 159struct nfs_server *nfs_alloc_server(void);
 160void nfs_server_copy_userdata(struct nfs_server *, struct nfs_server *);
 161
 162extern void nfs_cleanup_cb_ident_idr(struct net *);
 163extern void nfs_put_client(struct nfs_client *);
 164extern void nfs_free_client(struct nfs_client *);
 165extern struct nfs_client *nfs4_find_client_ident(struct net *, int);
 166extern struct nfs_client *
 167nfs4_find_client_sessionid(struct net *, const struct sockaddr *,
 168                                struct nfs4_sessionid *);
 169extern struct nfs_server *nfs_create_server(struct nfs_mount_info *,
 170                                        struct nfs_subversion *);
 171extern struct nfs_server *nfs4_create_server(
 172                                        struct nfs_mount_info *,
 173                                        struct nfs_subversion *);
 174extern struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *,
 175                                                      struct nfs_fh *);
 176extern void nfs_free_server(struct nfs_server *server);
 177extern struct nfs_server *nfs_clone_server(struct nfs_server *,
 178                                           struct nfs_fh *,
 179                                           struct nfs_fattr *,
 180                                           rpc_authflavor_t);
 181extern int nfs_wait_client_init_complete(const struct nfs_client *clp);
 182extern void nfs_mark_client_ready(struct nfs_client *clp, int state);
 183extern 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
 189extern int __init nfs_fs_proc_init(void);
 190extern void nfs_fs_proc_exit(void);
 191#else
 192static inline int nfs_fs_proc_init(void)
 193{
 194        return 0;
 195}
 196static inline void nfs_fs_proc_exit(void)
 197{
 198}
 199#endif
 200
 201#ifdef CONFIG_NFS_V4_1
 202int nfs_sockaddr_match_ipaddr(const struct sockaddr *, const struct sockaddr *);
 203#endif
 204
 205/* nfs3client.c */
 206#if IS_ENABLED(CONFIG_NFS_V3)
 207struct nfs_server *nfs3_create_server(struct nfs_mount_info *, struct nfs_subversion *);
 208struct 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 */
 213extern struct svc_version nfs4_callback_version1;
 214extern struct svc_version nfs4_callback_version4;
 215
 216struct nfs_pageio_descriptor;
 217/* pagelist.c */
 218extern int __init nfs_init_nfspagecache(void);
 219extern void nfs_destroy_nfspagecache(void);
 220extern int __init nfs_init_readpagecache(void);
 221extern void nfs_destroy_readpagecache(void);
 222extern int __init nfs_init_writepagecache(void);
 223extern void nfs_destroy_writepagecache(void);
 224
 225extern int __init nfs_init_directcache(void);
 226extern void nfs_destroy_directcache(void);
 227extern bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount);
 228extern void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
 229                              struct nfs_pgio_header *hdr,
 230                              void (*release)(struct nfs_pgio_header *hdr));
 231void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos);
 232
 233/* nfs2xdr.c */
 234extern struct rpc_procinfo nfs_procedures[];
 235extern int nfs2_decode_dirent(struct xdr_stream *,
 236                                struct nfs_entry *, int);
 237
 238/* nfs3xdr.c */
 239extern struct rpc_procinfo nfs3_procedures[];
 240extern int nfs3_decode_dirent(struct xdr_stream *,
 241                                struct nfs_entry *, int);
 242
 243/* nfs4xdr.c */
 244#if IS_ENABLED(CONFIG_NFS_V4)
 245extern int nfs4_decode_dirent(struct xdr_stream *,
 246                                struct nfs_entry *, int);
 247#endif
 248#ifdef CONFIG_NFS_V4_1
 249extern const u32 nfs41_maxread_overhead;
 250extern const u32 nfs41_maxwrite_overhead;
 251#endif
 252
 253/* nfs4proc.c */
 254#if IS_ENABLED(CONFIG_NFS_V4)
 255extern struct rpc_procinfo nfs4_procedures[];
 256#endif
 257
 258/* proc.c */
 259void nfs_close_context(struct nfs_open_context *ctx, int is_sync);
 260extern 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 */
 265extern int nfs_access_cache_shrinker(struct shrinker *shrink,
 266                                        struct shrink_control *sc);
 267struct dentry *nfs_lookup(struct inode *, struct dentry *, unsigned int);
 268int nfs_create(struct inode *, struct dentry *, umode_t, bool);
 269int nfs_mkdir(struct inode *, struct dentry *, umode_t);
 270int nfs_rmdir(struct inode *, struct dentry *);
 271int nfs_unlink(struct inode *, struct dentry *);
 272int nfs_symlink(struct inode *, struct dentry *, const char *);
 273int nfs_link(struct dentry *, struct inode *, struct dentry *);
 274int nfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
 275int nfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 276
 277/* file.c */
 278int nfs_file_fsync_commit(struct file *, loff_t, loff_t, int);
 279loff_t nfs_file_llseek(struct file *, loff_t, int);
 280int nfs_file_flush(struct file *, fl_owner_t);
 281ssize_t nfs_file_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 282ssize_t nfs_file_splice_read(struct file *, loff_t *, struct pipe_inode_info *,
 283                             size_t, unsigned int);
 284int nfs_file_mmap(struct file *, struct vm_area_struct *);
 285ssize_t nfs_file_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 286int nfs_file_release(struct inode *, struct file *);
 287int nfs_lock(struct file *, int, struct file_lock *);
 288int nfs_flock(struct file *, int, struct file_lock *);
 289ssize_t nfs_file_splice_write(struct pipe_inode_info *, struct file *, loff_t *,
 290                              size_t, unsigned int);
 291int nfs_check_flags(int);
 292int nfs_setlease(struct file *, long, struct file_lock **);
 293
 294/* inode.c */
 295extern struct workqueue_struct *nfsiod_workqueue;
 296extern struct inode *nfs_alloc_inode(struct super_block *sb);
 297extern void nfs_destroy_inode(struct inode *);
 298extern int nfs_write_inode(struct inode *, struct writeback_control *);
 299extern int nfs_drop_inode(struct inode *);
 300extern void nfs_clear_inode(struct inode *);
 301extern void nfs_evict_inode(struct inode *);
 302void nfs_zap_acl_cache(struct inode *inode);
 303extern int nfs_wait_bit_killable(void *word);
 304
 305/* super.c */
 306extern const struct super_operations nfs_sops;
 307extern struct file_system_type nfs_fs_type;
 308extern struct file_system_type nfs_xdev_fs_type;
 309#if IS_ENABLED(CONFIG_NFS_V4)
 310extern struct file_system_type nfs4_xdev_fs_type;
 311extern struct file_system_type nfs4_referral_fs_type;
 312#endif
 313struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
 314                        struct nfs_subversion *);
 315void nfs_initialise_sb(struct super_block *);
 316int nfs_set_sb_security(struct super_block *, struct dentry *, struct nfs_mount_info *);
 317int nfs_clone_sb_security(struct super_block *, struct dentry *, struct nfs_mount_info *);
 318struct dentry *nfs_fs_mount_common(struct nfs_server *, int, const char *,
 319                                   struct nfs_mount_info *, struct nfs_subversion *);
 320struct dentry *nfs_fs_mount(struct file_system_type *, int, const char *, void *);
 321struct dentry * nfs_xdev_mount_common(struct file_system_type *, int,
 322                const char *, struct nfs_mount_info *);
 323void nfs_kill_super(struct super_block *);
 324void nfs_fill_super(struct super_block *, struct nfs_mount_info *);
 325
 326extern struct rpc_stat nfs_rpcstat;
 327
 328extern int __init register_nfs_fs(void);
 329extern void __exit unregister_nfs_fs(void);
 330extern void nfs_sb_active(struct super_block *sb);
 331extern void nfs_sb_deactive(struct super_block *sb);
 332extern void nfs_sb_deactive_async(struct super_block *sb);
 333
 334/* namespace.c */
 335#define NFS_PATH_CANONICAL 1
 336extern char *nfs_path(char **p, struct dentry *dentry,
 337                      char *buffer, ssize_t buflen, unsigned flags);
 338extern struct vfsmount *nfs_d_automount(struct path *path);
 339struct vfsmount *nfs_submount(struct nfs_server *, struct dentry *,
 340                              struct nfs_fh *, struct nfs_fattr *);
 341struct vfsmount *nfs_do_submount(struct dentry *, struct nfs_fh *,
 342                                 struct nfs_fattr *, rpc_authflavor_t);
 343
 344/* getroot.c */
 345extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *,
 346                                   const char *);
 347#if IS_ENABLED(CONFIG_NFS_V4)
 348extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *,
 349                                    const char *);
 350
 351extern int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh);
 352#endif
 353
 354struct nfs_pgio_completion_ops;
 355/* read.c */
 356extern struct nfs_read_header *nfs_readhdr_alloc(void);
 357extern void nfs_readhdr_free(struct nfs_pgio_header *hdr);
 358extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
 359                        struct inode *inode,
 360                        const struct nfs_pgio_completion_ops *compl_ops);
 361extern int nfs_initiate_read(struct rpc_clnt *clnt,
 362                             struct nfs_read_data *data,
 363                             const struct rpc_call_ops *call_ops, int flags);
 364extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
 365extern int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
 366                              struct nfs_pgio_header *hdr);
 367extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);
 368extern void nfs_readdata_release(struct nfs_read_data *rdata);
 369
 370/* super.c */
 371void nfs_clone_super(struct super_block *, struct nfs_mount_info *);
 372void nfs_umount_begin(struct super_block *);
 373int  nfs_statfs(struct dentry *, struct kstatfs *);
 374int  nfs_show_options(struct seq_file *, struct dentry *);
 375int  nfs_show_devname(struct seq_file *, struct dentry *);
 376int  nfs_show_path(struct seq_file *, struct dentry *);
 377int  nfs_show_stats(struct seq_file *, struct dentry *);
 378void nfs_put_super(struct super_block *);
 379int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 380
 381/* write.c */
 382extern void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 383                        struct inode *inode, int ioflags,
 384                        const struct nfs_pgio_completion_ops *compl_ops);
 385extern struct nfs_write_header *nfs_writehdr_alloc(void);
 386extern void nfs_writehdr_free(struct nfs_pgio_header *hdr);
 387extern int nfs_generic_flush(struct nfs_pageio_descriptor *desc,
 388                             struct nfs_pgio_header *hdr);
 389extern void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio);
 390extern void nfs_writedata_release(struct nfs_write_data *wdata);
 391extern void nfs_commit_free(struct nfs_commit_data *p);
 392extern int nfs_initiate_write(struct rpc_clnt *clnt,
 393                              struct nfs_write_data *data,
 394                              const struct rpc_call_ops *call_ops,
 395                              int how, int flags);
 396extern void nfs_write_prepare(struct rpc_task *task, void *calldata);
 397extern void nfs_commit_prepare(struct rpc_task *task, void *calldata);
 398extern int nfs_initiate_commit(struct rpc_clnt *clnt,
 399                               struct nfs_commit_data *data,
 400                               const struct rpc_call_ops *call_ops,
 401                               int how, int flags);
 402extern void nfs_init_commit(struct nfs_commit_data *data,
 403                            struct list_head *head,
 404                            struct pnfs_layout_segment *lseg,
 405                            struct nfs_commit_info *cinfo);
 406int nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
 407                         struct nfs_commit_info *cinfo, int max);
 408int nfs_scan_commit(struct inode *inode, struct list_head *dst,
 409                    struct nfs_commit_info *cinfo);
 410void nfs_mark_request_commit(struct nfs_page *req,
 411                             struct pnfs_layout_segment *lseg,
 412                             struct nfs_commit_info *cinfo);
 413int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
 414                            int how, struct nfs_commit_info *cinfo);
 415void nfs_retry_commit(struct list_head *page_list,
 416                      struct pnfs_layout_segment *lseg,
 417                      struct nfs_commit_info *cinfo);
 418void nfs_commitdata_release(struct nfs_commit_data *data);
 419void nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
 420                                 struct nfs_commit_info *cinfo);
 421void nfs_request_remove_commit_list(struct nfs_page *req,
 422                                    struct nfs_commit_info *cinfo);
 423void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 424                    struct inode *inode,
 425                    struct nfs_direct_req *dreq);
 426
 427#ifdef CONFIG_MIGRATION
 428extern int nfs_migrate_page(struct address_space *,
 429                struct page *, struct page *, enum migrate_mode);
 430#else
 431#define nfs_migrate_page NULL
 432#endif
 433
 434/* direct.c */
 435void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
 436                              struct nfs_direct_req *dreq);
 437static inline void nfs_inode_dio_wait(struct inode *inode)
 438{
 439        inode_dio_wait(inode);
 440}
 441extern ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq);
 442
 443/* nfs4proc.c */
 444extern void __nfs4_read_done_cb(struct nfs_read_data *);
 445extern struct nfs_client *nfs4_init_client(struct nfs_client *clp,
 446                            const struct rpc_timeout *timeparms,
 447                            const char *ip_addr,
 448                            rpc_authflavor_t authflavour);
 449extern int nfs40_walk_client_list(struct nfs_client *clp,
 450                                struct nfs_client **result,
 451                                struct rpc_cred *cred);
 452extern int nfs41_walk_client_list(struct nfs_client *clp,
 453                                struct nfs_client **result,
 454                                struct rpc_cred *cred);
 455
 456/*
 457 * Determine the device name as a string
 458 */
 459static inline char *nfs_devname(struct dentry *dentry,
 460                                char *buffer, ssize_t buflen)
 461{
 462        char *dummy;
 463        return nfs_path(&dummy, dentry, buffer, buflen, NFS_PATH_CANONICAL);
 464}
 465
 466/*
 467 * Determine the actual block size (and log2 thereof)
 468 */
 469static inline
 470unsigned long nfs_block_bits(unsigned long bsize, unsigned char *nrbitsp)
 471{
 472        /* make sure blocksize is a power of two */
 473        if ((bsize & (bsize - 1)) || nrbitsp) {
 474                unsigned char   nrbits;
 475
 476                for (nrbits = 31; nrbits && !(bsize & (1 << nrbits)); nrbits--)
 477                        ;
 478                bsize = 1 << nrbits;
 479                if (nrbitsp)
 480                        *nrbitsp = nrbits;
 481        }
 482
 483        return bsize;
 484}
 485
 486/*
 487 * Calculate the number of 512byte blocks used.
 488 */
 489static inline blkcnt_t nfs_calc_block_size(u64 tsize)
 490{
 491        blkcnt_t used = (tsize + 511) >> 9;
 492        return (used > ULONG_MAX) ? ULONG_MAX : used;
 493}
 494
 495/*
 496 * Compute and set NFS server blocksize
 497 */
 498static inline
 499unsigned long nfs_block_size(unsigned long bsize, unsigned char *nrbitsp)
 500{
 501        if (bsize < NFS_MIN_FILE_IO_SIZE)
 502                bsize = NFS_DEF_FILE_IO_SIZE;
 503        else if (bsize >= NFS_MAX_FILE_IO_SIZE)
 504                bsize = NFS_MAX_FILE_IO_SIZE;
 505
 506        return nfs_block_bits(bsize, nrbitsp);
 507}
 508
 509/*
 510 * Determine the maximum file size for a superblock
 511 */
 512static inline
 513void nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize)
 514{
 515        sb->s_maxbytes = (loff_t)maxfilesize;
 516        if (sb->s_maxbytes > MAX_LFS_FILESIZE || sb->s_maxbytes <= 0)
 517                sb->s_maxbytes = MAX_LFS_FILESIZE;
 518}
 519
 520/*
 521 * Determine the number of bytes of data the page contains
 522 */
 523static inline
 524unsigned int nfs_page_length(struct page *page)
 525{
 526        loff_t i_size = i_size_read(page_file_mapping(page)->host);
 527
 528        if (i_size > 0) {
 529                pgoff_t page_index = page_file_index(page);
 530                pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 531                if (page_index < end_index)
 532                        return PAGE_CACHE_SIZE;
 533                if (page_index == end_index)
 534                        return ((i_size - 1) & ~PAGE_CACHE_MASK) + 1;
 535        }
 536        return 0;
 537}
 538
 539/*
 540 * Convert a umode to a dirent->d_type
 541 */
 542static inline
 543unsigned char nfs_umode_to_dtype(umode_t mode)
 544{
 545        return (mode >> 12) & 15;
 546}
 547
 548/*
 549 * Determine the number of pages in an array of length 'len' and
 550 * with a base offset of 'base'
 551 */
 552static inline
 553unsigned int nfs_page_array_len(unsigned int base, size_t len)
 554{
 555        return ((unsigned long)len + (unsigned long)base +
 556                PAGE_SIZE - 1) >> PAGE_SHIFT;
 557}
 558
 559/*
 560 * Convert a struct timespec into a 64-bit change attribute
 561 *
 562 * This does approximately the same thing as timespec_to_ns(),
 563 * but for calculation efficiency, we multiply the seconds by
 564 * 1024*1024*1024.
 565 */
 566static inline
 567u64 nfs_timespec_to_change_attr(const struct timespec *ts)
 568{
 569        return ((u64)ts->tv_sec << 30) + ts->tv_nsec;
 570}
 571