linux-bk/include/linux/fs.h
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   1#ifndef _LINUX_FS_H
   2#define _LINUX_FS_H
   3
   4/*
   5 * This file has definitions for some important file table
   6 * structures etc.
   7 */
   8
   9#include <linux/config.h>
  10#include <linux/limits.h>
  11#include <linux/ioctl.h>
  12
  13/*
  14 * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
  15 * the file limit at runtime and only root can increase the per-process
  16 * nr_file rlimit, so it's safe to set up a ridiculously high absolute
  17 * upper limit on files-per-process.
  18 *
  19 * Some programs (notably those using select()) may have to be 
  20 * recompiled to take full advantage of the new limits..  
  21 */
  22
  23/* Fixed constants first: */
  24#undef NR_OPEN
  25#define NR_OPEN (1024*1024)     /* Absolute upper limit on fd num */
  26#define INR_OPEN 1024           /* Initial setting for nfile rlimits */
  27
  28#define BLOCK_SIZE_BITS 10
  29#define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
  30
  31/* And dynamically-tunable limits and defaults: */
  32struct files_stat_struct {
  33        int nr_files;           /* read only */
  34        int nr_free_files;      /* read only */
  35        int max_files;          /* tunable */
  36};
  37extern struct files_stat_struct files_stat;
  38
  39struct inodes_stat_t {
  40        int nr_inodes;
  41        int nr_unused;
  42        int dummy[5];
  43};
  44extern struct inodes_stat_t inodes_stat;
  45
  46extern int leases_enable, lease_break_time;
  47
  48#ifdef CONFIG_DNOTIFY
  49extern int dir_notify_enable;
  50#endif
  51
  52#define NR_FILE  8192   /* this can well be larger on a larger system */
  53
  54#define MAY_EXEC 1
  55#define MAY_WRITE 2
  56#define MAY_READ 4
  57#define MAY_APPEND 8
  58
  59#define FMODE_READ 1
  60#define FMODE_WRITE 2
  61
  62/* Internal kernel extensions */
  63#define FMODE_LSEEK     4
  64#define FMODE_PREAD     8
  65#define FMODE_PWRITE    FMODE_PREAD     /* These go hand in hand */
  66
  67#define RW_MASK         1
  68#define RWA_MASK        2
  69#define READ 0
  70#define WRITE 1
  71#define READA 2         /* read-ahead  - don't block if no resources */
  72#define SPECIAL 4       /* For non-blockdevice requests in request queue */
  73#define READ_SYNC       (READ | (1 << BIO_RW_SYNC))
  74#define WRITE_SYNC      (WRITE | (1 << BIO_RW_SYNC))
  75#define WRITE_BARRIER   ((1 << BIO_RW) | (1 << BIO_RW_BARRIER))
  76
  77#define SEL_IN          1
  78#define SEL_OUT         2
  79#define SEL_EX          4
  80
  81/* public flags for file_system_type */
  82#define FS_REQUIRES_DEV 1 
  83#define FS_BINARY_MOUNTDATA 2
  84#define FS_REVAL_DOT    16384   /* Check the paths ".", ".." for staleness */
  85#define FS_ODD_RENAME   32768   /* Temporary stuff; will go away as soon
  86                                  * as nfs_rename() will be cleaned up
  87                                  */
  88/*
  89 * These are the fs-independent mount-flags: up to 32 flags are supported
  90 */
  91#define MS_RDONLY        1      /* Mount read-only */
  92#define MS_NOSUID        2      /* Ignore suid and sgid bits */
  93#define MS_NODEV         4      /* Disallow access to device special files */
  94#define MS_NOEXEC        8      /* Disallow program execution */
  95#define MS_SYNCHRONOUS  16      /* Writes are synced at once */
  96#define MS_REMOUNT      32      /* Alter flags of a mounted FS */
  97#define MS_MANDLOCK     64      /* Allow mandatory locks on an FS */
  98#define MS_DIRSYNC      128     /* Directory modifications are synchronous */
  99#define MS_NOATIME      1024    /* Do not update access times. */
 100#define MS_NODIRATIME   2048    /* Do not update directory access times */
 101#define MS_BIND         4096
 102#define MS_MOVE         8192
 103#define MS_REC          16384
 104#define MS_VERBOSE      32768
 105#define MS_POSIXACL     (1<<16) /* VFS does not apply the umask */
 106#define MS_ACTIVE       (1<<30)
 107#define MS_NOUSER       (1<<31)
 108
 109/*
 110 * Superblock flags that can be altered by MS_REMOUNT
 111 */
 112#define MS_RMT_MASK     (MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_NOATIME|\
 113                         MS_NODIRATIME)
 114
 115/*
 116 * Old magic mount flag and mask
 117 */
 118#define MS_MGC_VAL 0xC0ED0000
 119#define MS_MGC_MSK 0xffff0000
 120
 121/* Inode flags - they have nothing to superblock flags now */
 122
 123#define S_SYNC          1       /* Writes are synced at once */
 124#define S_NOATIME       2       /* Do not update access times */
 125#define S_APPEND        4       /* Append-only file */
 126#define S_IMMUTABLE     8       /* Immutable file */
 127#define S_DEAD          16      /* removed, but still open directory */
 128#define S_NOQUOTA       32      /* Inode is not counted to quota */
 129#define S_DIRSYNC       64      /* Directory modifications are synchronous */
 130#define S_NOCMTIME      128     /* Do not update file c/mtime */
 131#define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
 132
 133/*
 134 * Note that nosuid etc flags are inode-specific: setting some file-system
 135 * flags just means all the inodes inherit those flags by default. It might be
 136 * possible to override it selectively if you really wanted to with some
 137 * ioctl() that is not currently implemented.
 138 *
 139 * Exception: MS_RDONLY is always applied to the entire file system.
 140 *
 141 * Unfortunately, it is possible to change a filesystems flags with it mounted
 142 * with files in use.  This means that all of the inodes will not have their
 143 * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
 144 * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
 145 */
 146#define __IS_FLG(inode,flg) ((inode)->i_sb->s_flags & (flg))
 147
 148#define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY)
 149#define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
 150                                        ((inode)->i_flags & S_SYNC))
 151#define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
 152                                        ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
 153#define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
 154
 155#define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
 156#define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
 157#define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
 158#define IS_NOATIME(inode)       (__IS_FLG(inode, MS_NOATIME) || ((inode)->i_flags & S_NOATIME))
 159#define IS_NODIRATIME(inode)    __IS_FLG(inode, MS_NODIRATIME)
 160#define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
 161
 162#define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
 163#define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
 164#define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
 165
 166/* the read-only stuff doesn't really belong here, but any other place is
 167   probably as bad and I don't want to create yet another include file. */
 168
 169#define BLKROSET   _IO(0x12,93) /* set device read-only (0 = read-write) */
 170#define BLKROGET   _IO(0x12,94) /* get read-only status (0 = read_write) */
 171#define BLKRRPART  _IO(0x12,95) /* re-read partition table */
 172#define BLKGETSIZE _IO(0x12,96) /* return device size /512 (long *arg) */
 173#define BLKFLSBUF  _IO(0x12,97) /* flush buffer cache */
 174#define BLKRASET   _IO(0x12,98) /* set read ahead for block device */
 175#define BLKRAGET   _IO(0x12,99) /* get current read ahead setting */
 176#define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
 177#define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
 178#define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
 179#define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
 180#define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
 181#if 0
 182#define BLKPG      _IO(0x12,105)/* See blkpg.h */
 183
 184/* Some people are morons.  Do not use sizeof! */
 185
 186#define BLKELVGET  _IOR(0x12,106,size_t)/* elevator get */
 187#define BLKELVSET  _IOW(0x12,107,size_t)/* elevator set */
 188/* This was here just to show that the number is taken -
 189   probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
 190#endif
 191/* A jump here: 108-111 have been used for various private purposes. */
 192#define BLKBSZGET  _IOR(0x12,112,size_t)
 193#define BLKBSZSET  _IOW(0x12,113,size_t)
 194#define BLKGETSIZE64 _IOR(0x12,114,size_t)      /* return device size in bytes (u64 *arg) */
 195
 196#define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
 197#define FIBMAP     _IO(0x00,1)  /* bmap access */
 198#define FIGETBSZ   _IO(0x00,2)  /* get the block size used for bmap */
 199
 200#ifdef __KERNEL__
 201
 202#include <linux/linkage.h>
 203#include <linux/wait.h>
 204#include <linux/types.h>
 205#include <linux/kdev_t.h>
 206#include <linux/dcache.h>
 207#include <linux/stat.h>
 208#include <linux/cache.h>
 209#include <linux/kobject.h>
 210#include <linux/list.h>
 211#include <linux/radix-tree.h>
 212#include <linux/prio_tree.h>
 213#include <linux/audit.h>
 214#include <linux/init.h>
 215
 216#include <asm/atomic.h>
 217#include <asm/semaphore.h>
 218#include <asm/byteorder.h>
 219
 220struct iovec;
 221struct nameidata;
 222struct pipe_inode_info;
 223struct poll_table_struct;
 224struct kstatfs;
 225struct vm_area_struct;
 226struct vfsmount;
 227
 228/* Used to be a macro which just called the function, now just a function */
 229extern void update_atime (struct inode *);
 230
 231extern void __init inode_init(unsigned long);
 232extern void __init inode_init_early(void);
 233extern void __init mnt_init(unsigned long);
 234extern void __init files_init(unsigned long);
 235
 236struct buffer_head;
 237typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 238                        struct buffer_head *bh_result, int create);
 239typedef int (get_blocks_t)(struct inode *inode, sector_t iblock,
 240                        unsigned long max_blocks,
 241                        struct buffer_head *bh_result, int create);
 242typedef void (dio_iodone_t)(struct inode *inode, loff_t offset,
 243                        ssize_t bytes, void *private);
 244
 245/*
 246 * Attribute flags.  These should be or-ed together to figure out what
 247 * has been changed!
 248 */
 249#define ATTR_MODE       1
 250#define ATTR_UID        2
 251#define ATTR_GID        4
 252#define ATTR_SIZE       8
 253#define ATTR_ATIME      16
 254#define ATTR_MTIME      32
 255#define ATTR_CTIME      64
 256#define ATTR_ATIME_SET  128
 257#define ATTR_MTIME_SET  256
 258#define ATTR_FORCE      512     /* Not a change, but a change it */
 259#define ATTR_ATTR_FLAG  1024
 260#define ATTR_KILL_SUID  2048
 261#define ATTR_KILL_SGID  4096
 262
 263/*
 264 * This is the Inode Attributes structure, used for notify_change().  It
 265 * uses the above definitions as flags, to know which values have changed.
 266 * Also, in this manner, a Filesystem can look at only the values it cares
 267 * about.  Basically, these are the attributes that the VFS layer can
 268 * request to change from the FS layer.
 269 *
 270 * Derek Atkins <warlord@MIT.EDU> 94-10-20
 271 */
 272struct iattr {
 273        unsigned int    ia_valid;
 274        umode_t         ia_mode;
 275        uid_t           ia_uid;
 276        gid_t           ia_gid;
 277        loff_t          ia_size;
 278        struct timespec ia_atime;
 279        struct timespec ia_mtime;
 280        struct timespec ia_ctime;
 281        unsigned int    ia_attr_flags;
 282};
 283
 284/*
 285 * This is the inode attributes flag definitions
 286 */
 287#define ATTR_FLAG_SYNCRONOUS    1       /* Syncronous write */
 288#define ATTR_FLAG_NOATIME       2       /* Don't update atime */
 289#define ATTR_FLAG_APPEND        4       /* Append-only file */
 290#define ATTR_FLAG_IMMUTABLE     8       /* Immutable file */
 291#define ATTR_FLAG_NODIRATIME    16      /* Don't update atime for directory */
 292
 293/*
 294 * Includes for diskquotas.
 295 */
 296#include <linux/quota.h>
 297
 298/*
 299 * oh the beauties of C type declarations.
 300 */
 301struct page;
 302struct address_space;
 303struct writeback_control;
 304struct kiocb;
 305
 306struct address_space_operations {
 307        int (*writepage)(struct page *page, struct writeback_control *wbc);
 308        int (*readpage)(struct file *, struct page *);
 309        int (*sync_page)(struct page *);
 310
 311        /* Write back some dirty pages from this mapping. */
 312        int (*writepages)(struct address_space *, struct writeback_control *);
 313
 314        /* Set a page dirty */
 315        int (*set_page_dirty)(struct page *page);
 316
 317        int (*readpages)(struct file *filp, struct address_space *mapping,
 318                        struct list_head *pages, unsigned nr_pages);
 319
 320        /*
 321         * ext3 requires that a successful prepare_write() call be followed
 322         * by a commit_write() call - they must be balanced
 323         */
 324        int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
 325        int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
 326        /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
 327        sector_t (*bmap)(struct address_space *, sector_t);
 328        int (*invalidatepage) (struct page *, unsigned long);
 329        int (*releasepage) (struct page *, int);
 330        ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
 331                        loff_t offset, unsigned long nr_segs);
 332};
 333
 334struct backing_dev_info;
 335struct address_space {
 336        struct inode            *host;          /* owner: inode, block_device */
 337        struct radix_tree_root  page_tree;      /* radix tree of all pages */
 338        spinlock_t              tree_lock;      /* and spinlock protecting it */
 339        unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
 340        struct prio_tree_root   i_mmap;         /* tree of private and shared mappings */
 341        struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
 342        spinlock_t              i_mmap_lock;    /* protect tree, count, list */
 343        unsigned int            truncate_count; /* Cover race condition with truncate */
 344        unsigned long           nrpages;        /* number of total pages */
 345        pgoff_t                 writeback_index;/* writeback starts here */
 346        struct address_space_operations *a_ops; /* methods */
 347        unsigned long           flags;          /* error bits/gfp mask */
 348        struct backing_dev_info *backing_dev_info; /* device readahead, etc */
 349        spinlock_t              private_lock;   /* for use by the address_space */
 350        struct list_head        private_list;   /* ditto */
 351        struct address_space    *assoc_mapping; /* ditto */
 352} __attribute__((aligned(sizeof(long))));
 353        /*
 354         * On most architectures that alignment is already the case; but
 355         * must be enforced here for CRIS, to let the least signficant bit
 356         * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
 357         */
 358
 359struct block_device {
 360        dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
 361        struct inode *          bd_inode;       /* will die */
 362        int                     bd_openers;
 363        struct semaphore        bd_sem; /* open/close mutex */
 364        struct semaphore        bd_mount_sem;   /* mount mutex */
 365        struct list_head        bd_inodes;
 366        void *                  bd_holder;
 367        int                     bd_holders;
 368        struct block_device *   bd_contains;
 369        unsigned                bd_block_size;
 370        struct hd_struct *      bd_part;
 371        /* number of times partitions within this device have been opened. */
 372        unsigned                bd_part_count;
 373        int                     bd_invalidated;
 374        struct gendisk *        bd_disk;
 375        struct list_head        bd_list;
 376        struct backing_dev_info *bd_inode_backing_dev_info;
 377        /*
 378         * Private data.  You must have bd_claim'ed the block_device
 379         * to use this.  NOTE:  bd_claim allows an owner to claim
 380         * the same device multiple times, the owner must take special
 381         * care to not mess up bd_private for that case.
 382         */
 383        unsigned long           bd_private;
 384};
 385
 386/*
 387 * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
 388 * radix trees
 389 */
 390#define PAGECACHE_TAG_DIRTY     0
 391#define PAGECACHE_TAG_WRITEBACK 1
 392
 393int mapping_tagged(struct address_space *mapping, int tag);
 394
 395/*
 396 * Might pages of this file be mapped into userspace?
 397 */
 398static inline int mapping_mapped(struct address_space *mapping)
 399{
 400        return  !prio_tree_empty(&mapping->i_mmap) ||
 401                !list_empty(&mapping->i_mmap_nonlinear);
 402}
 403
 404/*
 405 * Might pages of this file have been modified in userspace?
 406 * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
 407 * marks vma as VM_SHARED if it is shared, and the file was opened for
 408 * writing i.e. vma may be mprotected writable even if now readonly.
 409 */
 410static inline int mapping_writably_mapped(struct address_space *mapping)
 411{
 412        return mapping->i_mmap_writable != 0;
 413}
 414
 415/*
 416 * Use sequence counter to get consistent i_size on 32-bit processors.
 417 */
 418#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
 419#include <linux/seqlock.h>
 420#define __NEED_I_SIZE_ORDERED
 421#define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
 422#else
 423#define i_size_ordered_init(inode) do { } while (0)
 424#endif
 425
 426struct inode {
 427        struct hlist_node       i_hash;
 428        struct list_head        i_list;
 429        struct list_head        i_sb_list;
 430        struct list_head        i_dentry;
 431        unsigned long           i_ino;
 432        atomic_t                i_count;
 433        umode_t                 i_mode;
 434        unsigned int            i_nlink;
 435        uid_t                   i_uid;
 436        gid_t                   i_gid;
 437        dev_t                   i_rdev;
 438        loff_t                  i_size;
 439        struct timespec         i_atime;
 440        struct timespec         i_mtime;
 441        struct timespec         i_ctime;
 442        unsigned int            i_blkbits;
 443        unsigned long           i_blksize;
 444        unsigned long           i_version;
 445        unsigned long           i_blocks;
 446        unsigned short          i_bytes;
 447        unsigned char           i_sock;
 448        spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
 449        struct semaphore        i_sem;
 450        struct rw_semaphore     i_alloc_sem;
 451        struct inode_operations *i_op;
 452        struct file_operations  *i_fop; /* former ->i_op->default_file_ops */
 453        struct super_block      *i_sb;
 454        struct file_lock        *i_flock;
 455        struct address_space    *i_mapping;
 456        struct address_space    i_data;
 457#ifdef CONFIG_QUOTA
 458        struct dquot            *i_dquot[MAXQUOTAS];
 459#endif
 460        /* These three should probably be a union */
 461        struct list_head        i_devices;
 462        struct pipe_inode_info  *i_pipe;
 463        struct block_device     *i_bdev;
 464        struct cdev             *i_cdev;
 465        int                     i_cindex;
 466
 467        __u32                   i_generation;
 468
 469#ifdef CONFIG_DNOTIFY
 470        unsigned long           i_dnotify_mask; /* Directory notify events */
 471        struct dnotify_struct   *i_dnotify; /* for directory notifications */
 472#endif
 473
 474        unsigned long           i_state;
 475        unsigned long           dirtied_when;   /* jiffies of first dirtying */
 476
 477        unsigned int            i_flags;
 478
 479        atomic_t                i_writecount;
 480        void                    *i_security;
 481        union {
 482                void            *generic_ip;
 483        } u;
 484#ifdef __NEED_I_SIZE_ORDERED
 485        seqcount_t              i_size_seqcount;
 486#endif
 487};
 488
 489/*
 490 * NOTE: in a 32bit arch with a preemptable kernel and
 491 * an UP compile the i_size_read/write must be atomic
 492 * with respect to the local cpu (unlike with preempt disabled),
 493 * but they don't need to be atomic with respect to other cpus like in
 494 * true SMP (so they need either to either locally disable irq around
 495 * the read or for example on x86 they can be still implemented as a
 496 * cmpxchg8b without the need of the lock prefix). For SMP compiles
 497 * and 64bit archs it makes no difference if preempt is enabled or not.
 498 */
 499static inline loff_t i_size_read(struct inode *inode)
 500{
 501#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
 502        loff_t i_size;
 503        unsigned int seq;
 504
 505        do {
 506                seq = read_seqcount_begin(&inode->i_size_seqcount);
 507                i_size = inode->i_size;
 508        } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
 509        return i_size;
 510#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
 511        loff_t i_size;
 512
 513        preempt_disable();
 514        i_size = inode->i_size;
 515        preempt_enable();
 516        return i_size;
 517#else
 518        return inode->i_size;
 519#endif
 520}
 521
 522
 523static inline void i_size_write(struct inode *inode, loff_t i_size)
 524{
 525#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
 526        write_seqcount_begin(&inode->i_size_seqcount);
 527        inode->i_size = i_size;
 528        write_seqcount_end(&inode->i_size_seqcount);
 529#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
 530        preempt_disable();
 531        inode->i_size = i_size;
 532        preempt_enable();
 533#else
 534        inode->i_size = i_size;
 535#endif
 536}
 537
 538static inline unsigned iminor(struct inode *inode)
 539{
 540        return MINOR(inode->i_rdev);
 541}
 542
 543static inline unsigned imajor(struct inode *inode)
 544{
 545        return MAJOR(inode->i_rdev);
 546}
 547
 548extern struct block_device *I_BDEV(struct inode *inode);
 549
 550struct fown_struct {
 551        rwlock_t lock;          /* protects pid, uid, euid fields */
 552        int pid;                /* pid or -pgrp where SIGIO should be sent */
 553        uid_t uid, euid;        /* uid/euid of process setting the owner */
 554        void *security;
 555        int signum;             /* posix.1b rt signal to be delivered on IO */
 556};
 557
 558/*
 559 * Track a single file's readahead state
 560 */
 561struct file_ra_state {
 562        unsigned long start;            /* Current window */
 563        unsigned long size;
 564        unsigned long flags;            /* ra flags RA_FLAG_xxx*/
 565        unsigned long cache_hit;        /* cache hit count*/
 566        unsigned long prev_page;        /* Cache last read() position */
 567        unsigned long ahead_start;      /* Ahead window */
 568        unsigned long ahead_size;
 569        unsigned long ra_pages;         /* Maximum readahead window */
 570        unsigned long mmap_hit;         /* Cache hit stat for mmap accesses */
 571        unsigned long mmap_miss;        /* Cache miss stat for mmap accesses */
 572};
 573#define RA_FLAG_MISS 0x01       /* a cache miss occured against this file */
 574#define RA_FLAG_INCACHE 0x02    /* file is already in cache */
 575
 576struct file {
 577        struct list_head        f_list;
 578        struct dentry           *f_dentry;
 579        struct vfsmount         *f_vfsmnt;
 580        struct file_operations  *f_op;
 581        atomic_t                f_count;
 582        unsigned int            f_flags;
 583        mode_t                  f_mode;
 584        int                     f_error;
 585        loff_t                  f_pos;
 586        struct fown_struct      f_owner;
 587        unsigned int            f_uid, f_gid;
 588        struct file_ra_state    f_ra;
 589
 590        size_t                  f_maxcount;
 591        unsigned long           f_version;
 592        void                    *f_security;
 593
 594        /* needed for tty driver, and maybe others */
 595        void                    *private_data;
 596
 597#ifdef CONFIG_EPOLL
 598        /* Used by fs/eventpoll.c to link all the hooks to this file */
 599        struct list_head        f_ep_links;
 600        spinlock_t              f_ep_lock;
 601#endif /* #ifdef CONFIG_EPOLL */
 602        struct address_space    *f_mapping;
 603};
 604extern spinlock_t files_lock;
 605#define file_list_lock() spin_lock(&files_lock);
 606#define file_list_unlock() spin_unlock(&files_lock);
 607
 608#define get_file(x)     atomic_inc(&(x)->f_count)
 609#define file_count(x)   atomic_read(&(x)->f_count)
 610
 611#define MAX_NON_LFS     ((1UL<<31) - 1)
 612
 613/* Page cache limit. The filesystems should put that into their s_maxbytes 
 614   limits, otherwise bad things can happen in VM. */ 
 615#if BITS_PER_LONG==32
 616#define MAX_LFS_FILESIZE        (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) 
 617#elif BITS_PER_LONG==64
 618#define MAX_LFS_FILESIZE        0x7fffffffffffffffUL
 619#endif
 620
 621#define FL_POSIX        1
 622#define FL_FLOCK        2
 623#define FL_ACCESS       8       /* not trying to lock, just looking */
 624#define FL_LOCKD        16      /* lock held by rpc.lockd */
 625#define FL_LEASE        32      /* lease held on this file */
 626#define FL_SLEEP        128     /* A blocking lock */
 627
 628/*
 629 * The POSIX file lock owner is determined by
 630 * the "struct files_struct" in the thread group
 631 * (or NULL for no owner - BSD locks).
 632 *
 633 * Lockd stuffs a "host" pointer into this.
 634 */
 635typedef struct files_struct *fl_owner_t;
 636
 637struct file_lock_operations {
 638        void (*fl_insert)(struct file_lock *);  /* lock insertion callback */
 639        void (*fl_remove)(struct file_lock *);  /* lock removal callback */
 640        void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
 641        void (*fl_release_private)(struct file_lock *);
 642};
 643
 644struct lock_manager_operations {
 645        int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
 646        void (*fl_notify)(struct file_lock *);  /* unblock callback */
 647        void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
 648        void (*fl_release_private)(struct file_lock *);
 649        void (*fl_break)(struct file_lock *);
 650};
 651
 652/* that will die - we need it for nfs_lock_info */
 653#include <linux/nfs_fs_i.h>
 654
 655struct file_lock {
 656        struct file_lock *fl_next;      /* singly linked list for this inode  */
 657        struct list_head fl_link;       /* doubly linked list of all locks */
 658        struct list_head fl_block;      /* circular list of blocked processes */
 659        fl_owner_t fl_owner;
 660        unsigned int fl_pid;
 661        wait_queue_head_t fl_wait;
 662        struct file *fl_file;
 663        unsigned char fl_flags;
 664        unsigned char fl_type;
 665        loff_t fl_start;
 666        loff_t fl_end;
 667
 668        struct fasync_struct *  fl_fasync; /* for lease break notifications */
 669        unsigned long fl_break_time;    /* for nonblocking lease breaks */
 670
 671        struct file_lock_operations *fl_ops;    /* Callbacks for filesystems */
 672        struct lock_manager_operations *fl_lmops;       /* Callbacks for lockmanagers */
 673        union {
 674                struct nfs_lock_info    nfs_fl;
 675        } fl_u;
 676};
 677
 678/* The following constant reflects the upper bound of the file/locking space */
 679#ifndef OFFSET_MAX
 680#define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
 681#define OFFSET_MAX      INT_LIMIT(loff_t)
 682#define OFFT_OFFSET_MAX INT_LIMIT(off_t)
 683#endif
 684
 685extern struct list_head file_lock_list;
 686
 687#include <linux/fcntl.h>
 688
 689extern int fcntl_getlk(struct file *, struct flock __user *);
 690extern int fcntl_setlk(struct file *, unsigned int, struct flock __user *);
 691
 692#if BITS_PER_LONG == 32
 693extern int fcntl_getlk64(struct file *, struct flock64 __user *);
 694extern int fcntl_setlk64(struct file *, unsigned int, struct flock64 __user *);
 695#endif
 696
 697extern void send_sigio(struct fown_struct *fown, int fd, int band);
 698extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
 699extern int fcntl_getlease(struct file *filp);
 700
 701/* fs/locks.c */
 702extern void locks_init_lock(struct file_lock *);
 703extern void locks_copy_lock(struct file_lock *, struct file_lock *);
 704extern void locks_remove_posix(struct file *, fl_owner_t);
 705extern void locks_remove_flock(struct file *);
 706extern struct file_lock *posix_test_lock(struct file *, struct file_lock *);
 707extern int posix_lock_file(struct file *, struct file_lock *);
 708extern int posix_lock_file_wait(struct file *, struct file_lock *);
 709extern void posix_block_lock(struct file_lock *, struct file_lock *);
 710extern void posix_unblock_lock(struct file *, struct file_lock *);
 711extern int posix_locks_deadlock(struct file_lock *, struct file_lock *);
 712extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
 713extern int __break_lease(struct inode *inode, unsigned int flags);
 714extern void lease_get_mtime(struct inode *, struct timespec *time);
 715extern int setlease(struct file *, long, struct file_lock **);
 716extern void remove_lease(struct file_lock *);
 717extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
 718extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
 719extern void steal_locks(fl_owner_t from);
 720
 721struct fasync_struct {
 722        int     magic;
 723        int     fa_fd;
 724        struct  fasync_struct   *fa_next; /* singly linked list */
 725        struct  file            *fa_file;
 726};
 727
 728#define FASYNC_MAGIC 0x4601
 729
 730/* SMP safe fasync helpers: */
 731extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
 732/* can be called from interrupts */
 733extern void kill_fasync(struct fasync_struct **, int, int);
 734/* only for net: no internal synchronization */
 735extern void __kill_fasync(struct fasync_struct *, int, int);
 736
 737extern int f_setown(struct file *filp, unsigned long arg, int force);
 738extern void f_delown(struct file *filp);
 739extern int send_sigurg(struct fown_struct *fown);
 740
 741/*
 742 *      Umount options
 743 */
 744
 745#define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
 746#define MNT_DETACH      0x00000002      /* Just detach from the tree */
 747#define MNT_EXPIRE      0x00000004      /* Mark for expiry */
 748
 749extern struct list_head super_blocks;
 750extern spinlock_t sb_lock;
 751
 752#define sb_entry(list)  list_entry((list), struct super_block, s_list)
 753#define S_BIAS (1<<30)
 754struct super_block {
 755        struct list_head        s_list;         /* Keep this first */
 756        dev_t                   s_dev;          /* search index; _not_ kdev_t */
 757        unsigned long           s_blocksize;
 758        unsigned long           s_old_blocksize;
 759        unsigned char           s_blocksize_bits;
 760        unsigned char           s_dirt;
 761        unsigned long long      s_maxbytes;     /* Max file size */
 762        struct file_system_type *s_type;
 763        struct super_operations *s_op;
 764        struct dquot_operations *dq_op;
 765        struct quotactl_ops     *s_qcop;
 766        struct export_operations *s_export_op;
 767        unsigned long           s_flags;
 768        unsigned long           s_magic;
 769        struct dentry           *s_root;
 770        struct rw_semaphore     s_umount;
 771        struct semaphore        s_lock;
 772        int                     s_count;
 773        int                     s_syncing;
 774        int                     s_need_sync_fs;
 775        atomic_t                s_active;
 776        void                    *s_security;
 777        struct xattr_handler    **s_xattr;
 778
 779        struct list_head        s_inodes;       /* all inodes */
 780        struct list_head        s_dirty;        /* dirty inodes */
 781        struct list_head        s_io;           /* parked for writeback */
 782        struct hlist_head       s_anon;         /* anonymous dentries for (nfs) exporting */
 783        struct list_head        s_files;
 784
 785        struct block_device     *s_bdev;
 786        struct list_head        s_instances;
 787        struct quota_info       s_dquot;        /* Diskquota specific options */
 788
 789        int                     s_frozen;
 790        wait_queue_head_t       s_wait_unfrozen;
 791
 792        char s_id[32];                          /* Informational name */
 793
 794        void                    *s_fs_info;     /* Filesystem private info */
 795
 796        /*
 797         * The next field is for VFS *only*. No filesystems have any business
 798         * even looking at it. You had been warned.
 799         */
 800        struct semaphore s_vfs_rename_sem;      /* Kludge */
 801
 802        /* Granuality of c/m/atime in ns.
 803           Cannot be worse than a second */
 804        u32                s_time_gran;
 805};
 806
 807extern struct timespec current_fs_time(struct super_block *sb);
 808
 809/*
 810 * Snapshotting support.
 811 */
 812enum {
 813        SB_UNFROZEN = 0,
 814        SB_FREEZE_WRITE = 1,
 815        SB_FREEZE_TRANS = 2,
 816};
 817
 818#define vfs_check_frozen(sb, level) \
 819        wait_event((sb)->s_wait_unfrozen, ((sb)->s_frozen < (level)))
 820
 821/*
 822 * Superblock locking.
 823 */
 824static inline void lock_super(struct super_block * sb)
 825{
 826        down(&sb->s_lock);
 827}
 828
 829static inline void unlock_super(struct super_block * sb)
 830{
 831        up(&sb->s_lock);
 832}
 833
 834/*
 835 * VFS helper functions..
 836 */
 837extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *);
 838extern int vfs_mkdir(struct inode *, struct dentry *, int);
 839extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
 840extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
 841extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 842extern int vfs_rmdir(struct inode *, struct dentry *);
 843extern int vfs_unlink(struct inode *, struct dentry *);
 844extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 845
 846/*
 847 * VFS dentry helper functions.
 848 */
 849extern void dentry_unhash(struct dentry *dentry);
 850
 851/*
 852 * File types
 853 *
 854 * NOTE! These match bits 12..15 of stat.st_mode
 855 * (ie "(i_mode >> 12) & 15").
 856 */
 857#define DT_UNKNOWN      0
 858#define DT_FIFO         1
 859#define DT_CHR          2
 860#define DT_DIR          4
 861#define DT_BLK          6
 862#define DT_REG          8
 863#define DT_LNK          10
 864#define DT_SOCK         12
 865#define DT_WHT          14
 866
 867#define OSYNC_METADATA  (1<<0)
 868#define OSYNC_DATA      (1<<1)
 869#define OSYNC_INODE     (1<<2)
 870int generic_osync_inode(struct inode *, struct address_space *, int);
 871
 872/*
 873 * This is the "filldir" function type, used by readdir() to let
 874 * the kernel specify what kind of dirent layout it wants to have.
 875 * This allows the kernel to read directories into kernel space or
 876 * to have different dirent layouts depending on the binary type.
 877 */
 878typedef int (*filldir_t)(void *, const char *, int, loff_t, ino_t, unsigned);
 879
 880struct block_device_operations {
 881        int (*open) (struct inode *, struct file *);
 882        int (*release) (struct inode *, struct file *);
 883        int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
 884        long (*compat_ioctl) (struct file *, unsigned, unsigned long);
 885        int (*media_changed) (struct gendisk *);
 886        int (*revalidate_disk) (struct gendisk *);
 887        struct module *owner;
 888};
 889
 890/*
 891 * "descriptor" for what we're up to with a read for sendfile().
 892 * This allows us to use the same read code yet
 893 * have multiple different users of the data that
 894 * we read from a file.
 895 *
 896 * The simplest case just copies the data to user
 897 * mode.
 898 */
 899typedef struct {
 900        size_t written;
 901        size_t count;
 902        union {
 903                char __user * buf;
 904                void *data;
 905        } arg;
 906        int error;
 907} read_descriptor_t;
 908
 909typedef int (*read_actor_t)(read_descriptor_t *, struct page *, unsigned long, unsigned long);
 910
 911/* These macros are for out of kernel modules to test that
 912 * the kernel supports the unlocked_ioctl and compat_ioctl
 913 * fields in struct file_operations. */
 914#define HAVE_COMPAT_IOCTL 1
 915#define HAVE_UNLOCKED_IOCTL 1
 916
 917/*
 918 * NOTE:
 919 * read, write, poll, fsync, readv, writev, unlocked_ioctl and compat_ioctl
 920 * can be called without the big kernel lock held in all filesystems.
 921 */
 922struct file_operations {
 923        struct module *owner;
 924        loff_t (*llseek) (struct file *, loff_t, int);
 925        ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
 926        ssize_t (*aio_read) (struct kiocb *, char __user *, size_t, loff_t);
 927        ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
 928        ssize_t (*aio_write) (struct kiocb *, const char __user *, size_t, loff_t);
 929        int (*readdir) (struct file *, void *, filldir_t);
 930        unsigned int (*poll) (struct file *, struct poll_table_struct *);
 931        int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
 932        long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
 933        long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
 934        int (*mmap) (struct file *, struct vm_area_struct *);
 935        int (*open) (struct inode *, struct file *);
 936        int (*flush) (struct file *);
 937        int (*release) (struct inode *, struct file *);
 938        int (*fsync) (struct file *, struct dentry *, int datasync);
 939        int (*aio_fsync) (struct kiocb *, int datasync);
 940        int (*fasync) (int, struct file *, int);
 941        int (*lock) (struct file *, int, struct file_lock *);
 942        ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *);
 943        ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *);
 944        ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, void *);
 945        ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
 946        unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 947        int (*check_flags)(int);
 948        int (*dir_notify)(struct file *filp, unsigned long arg);
 949        int (*flock) (struct file *, int, struct file_lock *);
 950};
 951
 952struct inode_operations {
 953        int (*create) (struct inode *,struct dentry *,int, struct nameidata *);
 954        struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *);
 955        int (*link) (struct dentry *,struct inode *,struct dentry *);
 956        int (*unlink) (struct inode *,struct dentry *);
 957        int (*symlink) (struct inode *,struct dentry *,const char *);
 958        int (*mkdir) (struct inode *,struct dentry *,int);
 959        int (*rmdir) (struct inode *,struct dentry *);
 960        int (*mknod) (struct inode *,struct dentry *,int,dev_t);
 961        int (*rename) (struct inode *, struct dentry *,
 962                        struct inode *, struct dentry *);
 963        int (*readlink) (struct dentry *, char __user *,int);
 964        int (*follow_link) (struct dentry *, struct nameidata *);
 965        void (*put_link) (struct dentry *, struct nameidata *);
 966        void (*truncate) (struct inode *);
 967        int (*permission) (struct inode *, int, struct nameidata *);
 968        int (*setattr) (struct dentry *, struct iattr *);
 969        int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
 970        int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
 971        ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
 972        ssize_t (*listxattr) (struct dentry *, char *, size_t);
 973        int (*removexattr) (struct dentry *, const char *);
 974};
 975
 976struct seq_file;
 977
 978extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
 979extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
 980extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
 981                unsigned long, loff_t *);
 982extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
 983                unsigned long, loff_t *);
 984
 985/*
 986 * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
 987 * without the big kernel lock held in all filesystems.
 988 */
 989struct super_operations {
 990        struct inode *(*alloc_inode)(struct super_block *sb);
 991        void (*destroy_inode)(struct inode *);
 992
 993        void (*read_inode) (struct inode *);
 994  
 995        void (*dirty_inode) (struct inode *);
 996        int (*write_inode) (struct inode *, int);
 997        void (*put_inode) (struct inode *);
 998        void (*drop_inode) (struct inode *);
 999        void (*delete_inode) (struct inode *);
1000        void (*put_super) (struct super_block *);
1001        void (*write_super) (struct super_block *);
1002        int (*sync_fs)(struct super_block *sb, int wait);
1003        void (*write_super_lockfs) (struct super_block *);
1004        void (*unlockfs) (struct super_block *);
1005        int (*statfs) (struct super_block *, struct kstatfs *);
1006        int (*remount_fs) (struct super_block *, int *, char *);
1007        void (*clear_inode) (struct inode *);
1008        void (*umount_begin) (struct super_block *);
1009
1010        int (*show_options)(struct seq_file *, struct vfsmount *);
1011
1012        ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1013        ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1014};
1015
1016/* Inode state bits.  Protected by inode_lock. */
1017#define I_DIRTY_SYNC            1 /* Not dirty enough for O_DATASYNC */
1018#define I_DIRTY_DATASYNC        2 /* Data-related inode changes pending */
1019#define I_DIRTY_PAGES           4 /* Data-related inode changes pending */
1020#define __I_LOCK                3
1021#define I_LOCK                  (1 << __I_LOCK)
1022#define I_FREEING               16
1023#define I_CLEAR                 32
1024#define I_NEW                   64
1025
1026#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1027
1028extern void __mark_inode_dirty(struct inode *, int);
1029static inline void mark_inode_dirty(struct inode *inode)
1030{
1031        __mark_inode_dirty(inode, I_DIRTY);
1032}
1033
1034static inline void mark_inode_dirty_sync(struct inode *inode)
1035{
1036        __mark_inode_dirty(inode, I_DIRTY_SYNC);
1037}
1038
1039static inline void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1040{
1041        /* per-mountpoint checks will go here */
1042        update_atime(dentry->d_inode);
1043}
1044
1045static inline void file_accessed(struct file *file)
1046{
1047        if (!(file->f_flags & O_NOATIME))
1048                touch_atime(file->f_vfsmnt, file->f_dentry);
1049}
1050
1051int sync_inode(struct inode *inode, struct writeback_control *wbc);
1052
1053/**
1054 * &export_operations - for nfsd to communicate with file systems
1055 * decode_fh:      decode a file handle fragment and return a &struct dentry
1056 * encode_fh:      encode a file handle fragment from a dentry
1057 * get_name:       find the name for a given inode in a given directory
1058 * get_parent:     find the parent of a given directory
1059 * get_dentry:     find a dentry for the inode given a file handle sub-fragment
1060 *
1061 * Description:
1062 *    The export_operations structure provides a means for nfsd to communicate
1063 *    with a particular exported file system  - particularly enabling nfsd and
1064 *    the filesystem to co-operate when dealing with file handles.
1065 *
1066 *    export_operations contains two basic operation for dealing with file handles,
1067 *    decode_fh() and encode_fh(), and allows for some other operations to be defined
1068 *    which standard helper routines use to get specific information from the
1069 *    filesystem.
1070 *
1071 *    nfsd encodes information use to determine which filesystem a filehandle
1072 *    applies to in the initial part of the file handle.  The remainder, termed a
1073 *    file handle fragment, is controlled completely by the filesystem.
1074 *    The standard helper routines assume that this fragment will contain one or two
1075 *    sub-fragments, one which identifies the file, and one which may be used to
1076 *    identify the (a) directory containing the file.
1077 *
1078 *    In some situations, nfsd needs to get a dentry which is connected into a
1079 *    specific part of the file tree.  To allow for this, it passes the function
1080 *    acceptable() together with a @context which can be used to see if the dentry
1081 *    is acceptable.  As there can be multiple dentrys for a given file, the filesystem
1082 *    should check each one for acceptability before looking for the next.  As soon
1083 *    as an acceptable one is found, it should be returned.
1084 *
1085 * decode_fh:
1086 *    @decode_fh is given a &struct super_block (@sb), a file handle fragment (@fh, @fh_len)
1087 *    and an acceptability testing function (@acceptable, @context).  It should return
1088 *    a &struct dentry which refers to the same file that the file handle fragment refers
1089 *    to,  and which passes the acceptability test.  If it cannot, it should return
1090 *    a %NULL pointer if the file was found but no acceptable &dentries were available, or
1091 *    a %ERR_PTR error code indicating why it couldn't be found (e.g. %ENOENT or %ENOMEM).
1092 *
1093 * encode_fh:
1094 *    @encode_fh should store in the file handle fragment @fh (using at most @max_len bytes)
1095 *    information that can be used by @decode_fh to recover the file refered to by the
1096 *    &struct dentry @de.  If the @connectable flag is set, the encode_fh() should store
1097 *    sufficient information so that a good attempt can be made to find not only
1098 *    the file but also it's place in the filesystem.   This typically means storing
1099 *    a reference to de->d_parent in the filehandle fragment.
1100 *    encode_fh() should return the number of bytes stored or a negative error code
1101 *    such as %-ENOSPC
1102 *
1103 * get_name:
1104 *    @get_name should find a name for the given @child in the given @parent directory.
1105 *    The name should be stored in the @name (with the understanding that it is already
1106 *    pointing to a a %NAME_MAX+1 sized buffer.   get_name() should return %0 on success,
1107 *    a negative error code or error.
1108 *    @get_name will be called without @parent->i_sem held.
1109 *
1110 * get_parent:
1111 *    @get_parent should find the parent directory for the given @child which is also
1112 *    a directory.  In the event that it cannot be found, or storage space cannot be
1113 *    allocated, a %ERR_PTR should be returned.
1114 *
1115 * get_dentry:
1116 *    Given a &super_block (@sb) and a pointer to a file-system specific inode identifier,
1117 *    possibly an inode number, (@inump) get_dentry() should find the identified inode and
1118 *    return a dentry for that inode.
1119 *    Any suitable dentry can be returned including, if necessary, a new dentry created
1120 *    with d_alloc_root.  The caller can then find any other extant dentrys by following the
1121 *    d_alias links.  If a new dentry was created using d_alloc_root, DCACHE_NFSD_DISCONNECTED
1122 *    should be set, and the dentry should be d_rehash()ed.
1123 *
1124 *    If the inode cannot be found, either a %NULL pointer or an %ERR_PTR code can be returned.
1125 *    The @inump will be whatever was passed to nfsd_find_fh_dentry() in either the
1126 *    @obj or @parent parameters.
1127 *
1128 * Locking rules:
1129 *  get_parent is called with child->d_inode->i_sem down
1130 *  get_name is not (which is possibly inconsistent)
1131 */
1132
1133struct export_operations {
1134        struct dentry *(*decode_fh)(struct super_block *sb, __u32 *fh, int fh_len, int fh_type,
1135                         int (*acceptable)(void *context, struct dentry *de),
1136                         void *context);
1137        int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
1138                         int connectable);
1139
1140        /* the following are only called from the filesystem itself */
1141        int (*get_name)(struct dentry *parent, char *name,
1142                        struct dentry *child);
1143        struct dentry * (*get_parent)(struct dentry *child);
1144        struct dentry * (*get_dentry)(struct super_block *sb, void *inump);
1145
1146        /* This is set by the exporting module to a standard helper */
1147        struct dentry * (*find_exported_dentry)(
1148                struct super_block *sb, void *obj, void *parent,
1149                int (*acceptable)(void *context, struct dentry *de),
1150                void *context);
1151
1152
1153};
1154
1155extern struct dentry *
1156find_exported_dentry(struct super_block *sb, void *obj, void *parent,
1157                     int (*acceptable)(void *context, struct dentry *de),
1158                     void *context);
1159
1160struct file_system_type {
1161        const char *name;
1162        int fs_flags;
1163        struct super_block *(*get_sb) (struct file_system_type *, int,
1164                                       const char *, void *);
1165        void (*kill_sb) (struct super_block *);
1166        struct module *owner;
1167        struct file_system_type * next;
1168        struct list_head fs_supers;
1169};
1170
1171struct super_block *get_sb_bdev(struct file_system_type *fs_type,
1172        int flags, const char *dev_name, void *data,
1173        int (*fill_super)(struct super_block *, void *, int));
1174struct super_block *get_sb_single(struct file_system_type *fs_type,
1175        int flags, void *data,
1176        int (*fill_super)(struct super_block *, void *, int));
1177struct super_block *get_sb_nodev(struct file_system_type *fs_type,
1178        int flags, void *data,
1179        int (*fill_super)(struct super_block *, void *, int));
1180void generic_shutdown_super(struct super_block *sb);
1181void kill_block_super(struct super_block *sb);
1182void kill_anon_super(struct super_block *sb);
1183void kill_litter_super(struct super_block *sb);
1184void deactivate_super(struct super_block *sb);
1185int set_anon_super(struct super_block *s, void *data);
1186struct super_block *sget(struct file_system_type *type,
1187                        int (*test)(struct super_block *,void *),
1188                        int (*set)(struct super_block *,void *),
1189                        void *data);
1190struct super_block *get_sb_pseudo(struct file_system_type *, char *,
1191                        struct super_operations *ops, unsigned long);
1192int __put_super(struct super_block *sb);
1193int __put_super_and_need_restart(struct super_block *sb);
1194void unnamed_dev_init(void);
1195
1196/* Alas, no aliases. Too much hassle with bringing module.h everywhere */
1197#define fops_get(fops) \
1198        (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
1199#define fops_put(fops) \
1200        do { if (fops) module_put((fops)->owner); } while(0)
1201
1202extern int register_filesystem(struct file_system_type *);
1203extern int unregister_filesystem(struct file_system_type *);
1204extern struct vfsmount *kern_mount(struct file_system_type *);
1205extern int may_umount_tree(struct vfsmount *);
1206extern int may_umount(struct vfsmount *);
1207extern long do_mount(char *, char *, char *, unsigned long, void *);
1208
1209extern int vfs_statfs(struct super_block *, struct kstatfs *);
1210
1211#define FLOCK_VERIFY_READ  1
1212#define FLOCK_VERIFY_WRITE 2
1213
1214extern int locks_mandatory_locked(struct inode *);
1215extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
1216
1217/*
1218 * Candidates for mandatory locking have the setgid bit set
1219 * but no group execute bit -  an otherwise meaningless combination.
1220 */
1221#define MANDATORY_LOCK(inode) \
1222        (IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
1223
1224static inline int locks_verify_locked(struct inode *inode)
1225{
1226        if (MANDATORY_LOCK(inode))
1227                return locks_mandatory_locked(inode);
1228        return 0;
1229}
1230
1231extern int rw_verify_area(int, struct file *, loff_t *, size_t);
1232
1233static inline int locks_verify_truncate(struct inode *inode,
1234                                    struct file *filp,
1235                                    loff_t size)
1236{
1237        if (inode->i_flock && MANDATORY_LOCK(inode))
1238                return locks_mandatory_area(
1239                        FLOCK_VERIFY_WRITE, inode, filp,
1240                        size < inode->i_size ? size : inode->i_size,
1241                        (size < inode->i_size ? inode->i_size - size
1242                         : size - inode->i_size)
1243                );
1244        return 0;
1245}
1246
1247static inline int break_lease(struct inode *inode, unsigned int mode)
1248{
1249        if (inode->i_flock)
1250                return __break_lease(inode, mode);
1251        return 0;
1252}
1253
1254/* fs/open.c */
1255
1256extern int do_truncate(struct dentry *, loff_t start);
1257extern struct file *filp_open(const char *, int, int);
1258extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
1259extern int filp_close(struct file *, fl_owner_t id);
1260extern char * getname(const char __user *);
1261
1262/* fs/dcache.c */
1263extern void __init vfs_caches_init_early(void);
1264extern void __init vfs_caches_init(unsigned long);
1265
1266#define __getname()     kmem_cache_alloc(names_cachep, SLAB_KERNEL)
1267#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
1268#ifndef CONFIG_AUDITSYSCALL
1269#define putname(name)   __putname(name)
1270#else
1271#define putname(name)                                                   \
1272        do {                                                            \
1273                if (unlikely(current->audit_context))                   \
1274                        audit_putname(name);                            \
1275                else                                                    \
1276                        __putname(name);                                \
1277        } while (0)
1278#endif
1279
1280extern int register_blkdev(unsigned int, const char *);
1281extern int unregister_blkdev(unsigned int, const char *);
1282extern struct block_device *bdget(dev_t);
1283extern void bd_set_size(struct block_device *, loff_t size);
1284extern void bd_forget(struct inode *inode);
1285extern void bdput(struct block_device *);
1286extern struct block_device *open_by_devnum(dev_t, unsigned);
1287extern struct file_operations def_blk_fops;
1288extern struct address_space_operations def_blk_aops;
1289extern struct file_operations def_chr_fops;
1290extern struct file_operations bad_sock_fops;
1291extern struct file_operations def_fifo_fops;
1292extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
1293extern int blkdev_ioctl(struct inode *, struct file *, unsigned, unsigned long);
1294extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
1295extern int blkdev_get(struct block_device *, mode_t, unsigned);
1296extern int blkdev_put(struct block_device *);
1297extern int bd_claim(struct block_device *, void *);
1298extern void bd_release(struct block_device *);
1299
1300/* fs/char_dev.c */
1301extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
1302extern int register_chrdev_region(dev_t, unsigned, const char *);
1303extern int register_chrdev(unsigned int, const char *,
1304                           struct file_operations *);
1305extern int unregister_chrdev(unsigned int, const char *);
1306extern void unregister_chrdev_region(dev_t, unsigned);
1307extern int chrdev_open(struct inode *, struct file *);
1308
1309/* fs/block_dev.c */
1310#define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
1311extern const char *__bdevname(dev_t, char *buffer);
1312extern const char *bdevname(struct block_device *bdev, char *buffer);
1313extern struct block_device *lookup_bdev(const char *);
1314extern struct block_device *open_bdev_excl(const char *, int, void *);
1315extern void close_bdev_excl(struct block_device *);
1316
1317extern void init_special_inode(struct inode *, umode_t, dev_t);
1318
1319/* Invalid inode operations -- fs/bad_inode.c */
1320extern void make_bad_inode(struct inode *);
1321extern int is_bad_inode(struct inode *);
1322
1323extern struct file_operations read_fifo_fops;
1324extern struct file_operations write_fifo_fops;
1325extern struct file_operations rdwr_fifo_fops;
1326extern struct file_operations read_pipe_fops;
1327extern struct file_operations write_pipe_fops;
1328extern struct file_operations rdwr_pipe_fops;
1329
1330extern int fs_may_remount_ro(struct super_block *);
1331
1332/*
1333 * return READ, READA, or WRITE
1334 */
1335#define bio_rw(bio)             ((bio)->bi_rw & (RW_MASK | RWA_MASK))
1336
1337/*
1338 * return data direction, READ or WRITE
1339 */
1340#define bio_data_dir(bio)       ((bio)->bi_rw & 1)
1341
1342extern int check_disk_change(struct block_device *);
1343extern int invalidate_inodes(struct super_block *);
1344extern int __invalidate_device(struct block_device *, int);
1345extern int invalidate_partition(struct gendisk *, int);
1346unsigned long invalidate_mapping_pages(struct address_space *mapping,
1347                                        pgoff_t start, pgoff_t end);
1348unsigned long invalidate_inode_pages(struct address_space *mapping);
1349static inline void invalidate_remote_inode(struct inode *inode)
1350{
1351        if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1352            S_ISLNK(inode->i_mode))
1353                invalidate_inode_pages(inode->i_mapping);
1354}
1355extern int invalidate_inode_pages2(struct address_space *mapping);
1356extern int write_inode_now(struct inode *, int);
1357extern int filemap_fdatawrite(struct address_space *);
1358extern int filemap_flush(struct address_space *);
1359extern int filemap_fdatawait(struct address_space *);
1360extern int filemap_write_and_wait(struct address_space *mapping);
1361extern void sync_supers(void);
1362extern void sync_filesystems(int wait);
1363extern void emergency_sync(void);
1364extern void emergency_remount(void);
1365extern int do_remount_sb(struct super_block *sb, int flags,
1366                         void *data, int force);
1367extern sector_t bmap(struct inode *, sector_t);
1368extern int setattr_mask(unsigned int);
1369extern int notify_change(struct dentry *, struct iattr *);
1370extern int permission(struct inode *, int, struct nameidata *);
1371extern int generic_permission(struct inode *, int,
1372                int (*check_acl)(struct inode *, int));
1373
1374extern int get_write_access(struct inode *);
1375extern int deny_write_access(struct file *);
1376static inline void put_write_access(struct inode * inode)
1377{
1378        atomic_dec(&inode->i_writecount);
1379}
1380static inline void allow_write_access(struct file *file)
1381{
1382        if (file)
1383                atomic_inc(&file->f_dentry->d_inode->i_writecount);
1384}
1385extern int do_pipe(int *);
1386
1387extern int open_namei(const char *, int, int, struct nameidata *);
1388extern int may_open(struct nameidata *, int, int);
1389
1390extern int kernel_read(struct file *, unsigned long, char *, unsigned long);
1391extern struct file * open_exec(const char *);
1392 
1393/* fs/dcache.c -- generic fs support functions */
1394extern int is_subdir(struct dentry *, struct dentry *);
1395extern ino_t find_inode_number(struct dentry *, struct qstr *);
1396
1397#include <linux/err.h>
1398
1399/* needed for stackable file system support */
1400extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
1401
1402extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin);
1403
1404extern void inode_init_once(struct inode *);
1405extern void iput(struct inode *);
1406extern struct inode * igrab(struct inode *);
1407extern ino_t iunique(struct super_block *, ino_t);
1408extern int inode_needs_sync(struct inode *inode);
1409extern void generic_delete_inode(struct inode *inode);
1410
1411extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1412                int (*test)(struct inode *, void *), void *data);
1413extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
1414
1415extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
1416extern struct inode * iget_locked(struct super_block *, unsigned long);
1417extern void unlock_new_inode(struct inode *);
1418
1419static inline struct inode *iget(struct super_block *sb, unsigned long ino)
1420{
1421        struct inode *inode = iget_locked(sb, ino);
1422        
1423        if (inode && (inode->i_state & I_NEW)) {
1424                sb->s_op->read_inode(inode);
1425                unlock_new_inode(inode);
1426        }
1427
1428        return inode;
1429}
1430
1431extern void __iget(struct inode * inode);
1432extern void clear_inode(struct inode *);
1433extern void destroy_inode(struct inode *);
1434extern struct inode *new_inode(struct super_block *);
1435extern int remove_suid(struct dentry *);
1436extern void remove_dquot_ref(struct super_block *, int, struct list_head *);
1437extern struct semaphore iprune_sem;
1438
1439extern void __insert_inode_hash(struct inode *, unsigned long hashval);
1440extern void remove_inode_hash(struct inode *);
1441static inline void insert_inode_hash(struct inode *inode) {
1442        __insert_inode_hash(inode, inode->i_ino);
1443}
1444
1445extern struct file * get_empty_filp(void);
1446extern void file_move(struct file *f, struct list_head *list);
1447extern void file_kill(struct file *f);
1448struct bio;
1449extern void submit_bio(int, struct bio *);
1450extern int bdev_read_only(struct block_device *);
1451extern int set_blocksize(struct block_device *, int);
1452extern int sb_set_blocksize(struct super_block *, int);
1453extern int sb_min_blocksize(struct super_block *, int);
1454
1455extern int generic_file_mmap(struct file *, struct vm_area_struct *);
1456extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
1457extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
1458extern int file_send_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
1459extern ssize_t generic_file_read(struct file *, char __user *, size_t, loff_t *);
1460int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
1461extern ssize_t generic_file_write(struct file *, const char __user *, size_t, loff_t *);
1462extern ssize_t generic_file_aio_read(struct kiocb *, char __user *, size_t, loff_t);
1463extern ssize_t __generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t *);
1464extern ssize_t generic_file_aio_write(struct kiocb *, const char __user *, size_t, loff_t);
1465extern ssize_t generic_file_aio_write_nolock(struct kiocb *, const struct iovec *,
1466                unsigned long, loff_t *);
1467extern ssize_t generic_file_direct_write(struct kiocb *, const struct iovec *,
1468                unsigned long *, loff_t, loff_t *, size_t, size_t);
1469extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *,
1470                unsigned long, loff_t, loff_t *, size_t, ssize_t);
1471extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
1472extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
1473ssize_t generic_file_write_nolock(struct file *file, const struct iovec *iov,
1474                                unsigned long nr_segs, loff_t *ppos);
1475extern ssize_t generic_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
1476extern void do_generic_mapping_read(struct address_space *mapping,
1477                                    struct file_ra_state *, struct file *,
1478                                    loff_t *, read_descriptor_t *, read_actor_t);
1479extern void
1480file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
1481extern ssize_t generic_file_direct_IO(int rw, struct kiocb *iocb,
1482        const struct iovec *iov, loff_t offset, unsigned long nr_segs);
1483extern ssize_t generic_file_readv(struct file *filp, const struct iovec *iov, 
1484        unsigned long nr_segs, loff_t *ppos);
1485ssize_t generic_file_writev(struct file *filp, const struct iovec *iov, 
1486                        unsigned long nr_segs, loff_t *ppos);
1487extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
1488extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
1489extern loff_t remote_llseek(struct file *file, loff_t offset, int origin);
1490extern int generic_file_open(struct inode * inode, struct file * filp);
1491extern int nonseekable_open(struct inode * inode, struct file * filp);
1492
1493static inline void do_generic_file_read(struct file * filp, loff_t *ppos,
1494                                        read_descriptor_t * desc,
1495                                        read_actor_t actor)
1496{
1497        do_generic_mapping_read(filp->f_mapping,
1498                                &filp->f_ra,
1499                                filp,
1500                                ppos,
1501                                desc,
1502                                actor);
1503}
1504
1505ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
1506        struct block_device *bdev, const struct iovec *iov, loff_t offset,
1507        unsigned long nr_segs, get_blocks_t get_blocks, dio_iodone_t end_io,
1508        int lock_type);
1509
1510enum {
1511        DIO_LOCKING = 1, /* need locking between buffered and direct access */
1512        DIO_NO_LOCKING,  /* bdev; no locking at all between buffered/direct */
1513        DIO_OWN_LOCKING, /* filesystem locks buffered and direct internally */
1514};
1515
1516static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
1517        struct inode *inode, struct block_device *bdev, const struct iovec *iov,
1518        loff_t offset, unsigned long nr_segs, get_blocks_t get_blocks,
1519        dio_iodone_t end_io)
1520{
1521        return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
1522                                nr_segs, get_blocks, end_io, DIO_LOCKING);
1523}
1524
1525static inline ssize_t blockdev_direct_IO_no_locking(int rw, struct kiocb *iocb,
1526        struct inode *inode, struct block_device *bdev, const struct iovec *iov,
1527        loff_t offset, unsigned long nr_segs, get_blocks_t get_blocks,
1528        dio_iodone_t end_io)
1529{
1530        return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
1531                                nr_segs, get_blocks, end_io, DIO_NO_LOCKING);
1532}
1533
1534static inline ssize_t blockdev_direct_IO_own_locking(int rw, struct kiocb *iocb,
1535        struct inode *inode, struct block_device *bdev, const struct iovec *iov,
1536        loff_t offset, unsigned long nr_segs, get_blocks_t get_blocks,
1537        dio_iodone_t end_io)
1538{
1539        return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
1540                                nr_segs, get_blocks, end_io, DIO_OWN_LOCKING);
1541}
1542
1543extern struct file_operations generic_ro_fops;
1544
1545#define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
1546
1547extern int vfs_readlink(struct dentry *, char __user *, int, const char *);
1548extern int vfs_follow_link(struct nameidata *, const char *);
1549extern int page_readlink(struct dentry *, char __user *, int);
1550extern int page_follow_link_light(struct dentry *, struct nameidata *);
1551extern void page_put_link(struct dentry *, struct nameidata *);
1552extern int page_symlink(struct inode *inode, const char *symname, int len);
1553extern struct inode_operations page_symlink_inode_operations;
1554extern int generic_readlink(struct dentry *, char __user *, int);
1555extern void generic_fillattr(struct inode *, struct kstat *);
1556extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
1557void inode_add_bytes(struct inode *inode, loff_t bytes);
1558void inode_sub_bytes(struct inode *inode, loff_t bytes);
1559loff_t inode_get_bytes(struct inode *inode);
1560void inode_set_bytes(struct inode *inode, loff_t bytes);
1561
1562extern int vfs_readdir(struct file *, filldir_t, void *);
1563
1564extern int vfs_stat(char __user *, struct kstat *);
1565extern int vfs_lstat(char __user *, struct kstat *);
1566extern int vfs_fstat(unsigned int, struct kstat *);
1567
1568extern int vfs_ioctl(struct file *, unsigned int, unsigned int, unsigned long);
1569
1570extern struct file_system_type *get_fs_type(const char *name);
1571extern struct super_block *get_super(struct block_device *);
1572extern struct super_block *user_get_super(dev_t);
1573extern void drop_super(struct super_block *sb);
1574
1575extern int dcache_dir_open(struct inode *, struct file *);
1576extern int dcache_dir_close(struct inode *, struct file *);
1577extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
1578extern int dcache_readdir(struct file *, void *, filldir_t);
1579extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
1580extern int simple_statfs(struct super_block *, struct kstatfs *);
1581extern int simple_link(struct dentry *, struct inode *, struct dentry *);
1582extern int simple_unlink(struct inode *, struct dentry *);
1583extern int simple_rmdir(struct inode *, struct dentry *);
1584extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
1585extern int simple_sync_file(struct file *, struct dentry *, int);
1586extern int simple_empty(struct dentry *);
1587extern int simple_readpage(struct file *file, struct page *page);
1588extern int simple_prepare_write(struct file *file, struct page *page,
1589                        unsigned offset, unsigned to);
1590extern int simple_commit_write(struct file *file, struct page *page,
1591                                unsigned offset, unsigned to);
1592
1593extern struct dentry *simple_lookup(struct inode *, struct dentry *, struct nameidata *);
1594extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
1595extern struct file_operations simple_dir_operations;
1596extern struct inode_operations simple_dir_inode_operations;
1597struct tree_descr { char *name; struct file_operations *ops; int mode; };
1598struct dentry *d_alloc_name(struct dentry *, const char *);
1599extern int simple_fill_super(struct super_block *, int, struct tree_descr *);
1600extern int simple_pin_fs(char *name, struct vfsmount **mount, int *count);
1601extern void simple_release_fs(struct vfsmount **mount, int *count);
1602
1603extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t *, const void *, size_t);
1604
1605extern int inode_change_ok(struct inode *, struct iattr *);
1606extern int __must_check inode_setattr(struct inode *, struct iattr *);
1607
1608extern void inode_update_time(struct inode *inode, int ctime_too);
1609
1610static inline ino_t parent_ino(struct dentry *dentry)
1611{
1612        ino_t res;
1613
1614        spin_lock(&dentry->d_lock);
1615        res = dentry->d_parent->d_inode->i_ino;
1616        spin_unlock(&dentry->d_lock);
1617        return res;
1618}
1619
1620/* kernel/fork.c */
1621extern int unshare_files(void);
1622
1623/* Transaction based IO helpers */
1624
1625/*
1626 * An argresp is stored in an allocated page and holds the
1627 * size of the argument or response, along with its content
1628 */
1629struct simple_transaction_argresp {
1630        ssize_t size;
1631        char data[0];
1632};
1633
1634#define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
1635
1636char *simple_transaction_get(struct file *file, const char __user *buf,
1637                                size_t size);
1638ssize_t simple_transaction_read(struct file *file, char __user *buf,
1639                                size_t size, loff_t *pos);
1640int simple_transaction_release(struct inode *inode, struct file *file);
1641
1642static inline void simple_transaction_set(struct file *file, size_t n)
1643{
1644        struct simple_transaction_argresp *ar = file->private_data;
1645
1646        BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
1647
1648        /*
1649         * The barrier ensures that ar->size will really remain zero until
1650         * ar->data is ready for reading.
1651         */
1652        smp_mb();
1653        ar->size = n;
1654}
1655
1656#ifdef CONFIG_SECURITY
1657static inline char *alloc_secdata(void)
1658{
1659        return (char *)get_zeroed_page(GFP_KERNEL);
1660}
1661
1662static inline void free_secdata(void *secdata)
1663{
1664        free_page((unsigned long)secdata);
1665}
1666#else
1667static inline char *alloc_secdata(void)
1668{
1669        return (char *)1;
1670}
1671
1672static inline void free_secdata(void *secdata)
1673{ }
1674#endif  /* CONFIG_SECURITY */
1675
1676#endif /* __KERNEL__ */
1677#endif /* _LINUX_FS_H */
1678
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