root/include/linux/fs.h

/* */

INCLUDED FROM

DEFINITIONS

1. buffer_uptodate
2. buffer_dirty
3. buffer_locked
4. buffer_req
5. buffer_touched
6. buffer_has_aged
7. buffer_protected
8. mark_buffer_uptodate
9. mark_buffer_clean
10. mark_buffer_dirty
11. brelse
12. bforget
13. iget

   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/linkage.h>
  10 #include <linux/limits.h>
  11 #include <linux/wait.h>
  12 #include <linux/types.h>
  13 #include <linux/vfs.h>
  14 #include <linux/net.h>
  15 #include <linux/kdev_t.h>
  16 #include <linux/ioctl.h>
  17 
  18 /*
  19  * It's silly to have NR_OPEN bigger than NR_FILE, but I'll fix
  20  * that later. Anyway, now the file code is no longer dependent
  21  * on bitmaps in unsigned longs, but uses the new fd_set structure..
  22  *
  23  * Some programs (notably those using select()) may have to be 
  24  * recompiled to take full advantage of the new limits..
  25  */
  26 #undef NR_OPEN
  27 #define NR_OPEN 256
  28 
  29 #define NR_INODE 2048   /* this should be bigger than NR_FILE */
  30 #define NR_FILE 1024    /* this can well be larger on a larger system */
  31 #define NR_SUPER 32
  32 #define NR_IHASH 131
  33 #define BLOCK_SIZE 1024
  34 #define BLOCK_SIZE_BITS 10
  35 
  36 #define MAY_EXEC 1
  37 #define MAY_WRITE 2
  38 #define MAY_READ 4
  39 
  40 #define FMODE_READ 1
  41 #define FMODE_WRITE 2
  42 
  43 #define READ 0
  44 #define WRITE 1
  45 #define READA 2         /* read-ahead - don't pause */
  46 #define WRITEA 3        /* "write-ahead" - silly, but somewhat useful */
  47 
  48 #ifndef NULL
  49 #define NULL ((void *) 0)
  50 #endif
  51 
  52 #define NIL_FILP        ((struct file *)0)
  53 #define SEL_IN          1
  54 #define SEL_OUT         2
  55 #define SEL_EX          4
  56 
  57 /*
  58  * These are the fs-independent mount-flags: up to 16 flags are supported
  59  */
  60 #define MS_RDONLY        1      /* Mount read-only */
  61 #define MS_NOSUID        2      /* Ignore suid and sgid bits */
  62 #define MS_NODEV         4      /* Disallow access to device special files */
  63 #define MS_NOEXEC        8      /* Disallow program execution */
  64 #define MS_SYNCHRONOUS  16      /* Writes are synced at once */
  65 #define MS_REMOUNT      32      /* Alter flags of a mounted FS */
  66 #define S_WRITE         128     /* Write on file/directory/symlink */
  67 #define S_APPEND        256     /* Append-only file */
  68 #define S_IMMUTABLE     512     /* Immutable file */
  69 
  70 /*
  71  * Flags that can be altered by MS_REMOUNT
  72  */
  73 #define MS_RMT_MASK (MS_RDONLY)
  74 
  75 /*
  76  * Magic mount flag number. Has to be or-ed to the flag values.
  77  */
  78 #define MS_MGC_VAL 0xC0ED0000   /* magic flag number to indicate "new" flags */
  79 #define MS_MGC_MSK 0xffff0000   /* magic flag number mask */
  80 
  81 /*
  82  * Note that read-only etc flags are inode-specific: setting some file-system
  83  * flags just means all the inodes inherit those flags by default. It might be
  84  * possible to override it selectively if you really wanted to with some
  85  * ioctl() that is not currently implemented.
  86  *
  87  * Exception: MS_RDONLY is always applied to the entire file system.
  88  */
  89 #define IS_RDONLY(inode) (((inode)->i_sb) && ((inode)->i_sb->s_flags & MS_RDONLY))
  90 #define IS_NOSUID(inode) ((inode)->i_flags & MS_NOSUID)
  91 #define IS_NODEV(inode) ((inode)->i_flags & MS_NODEV)
  92 #define IS_NOEXEC(inode) ((inode)->i_flags & MS_NOEXEC)
  93 #define IS_SYNC(inode) ((inode)->i_flags & MS_SYNCHRONOUS)
  94 
  95 #define IS_WRITABLE(inode) ((inode)->i_flags & S_WRITE)
  96 #define IS_APPEND(inode) ((inode)->i_flags & S_APPEND)
  97 #define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE)
  98 
  99 /* the read-only stuff doesn't really belong here, but any other place is
 100    probably as bad and I don't want to create yet another include file. */
 101 
 102 #define BLKROSET   _IO(0x12,93) /* set device read-only (0 = read-write) */
 103 #define BLKROGET   _IO(0x12,94) /* get read-only status (0 = read_write) */
 104 #define BLKRRPART  _IO(0x12,95) /* re-read partition table */
 105 #define BLKGETSIZE _IO(0x12,96) /* return device size */
 106 #define BLKFLSBUF  _IO(0x12,97) /* flush buffer cache */
 107 #define BLKRASET   _IO(0x12,98) /* Set read ahead for block device */
 108 #define BLKRAGET   _IO(0x12,99) /* get current read ahead setting */
 109 
 110 #define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
 111 #define FIBMAP     _IO(0x00,1)  /* bmap access */
 112 #define FIGETBSZ   _IO(0x00,2)  /* get the block size used for bmap */
 113 
 114 #ifdef __KERNEL__
 115 
 116 #include <asm/bitops.h>
 117 
 118 extern void buffer_init(void);
 119 extern unsigned long inode_init(unsigned long start, unsigned long end);
 120 extern unsigned long file_table_init(unsigned long start, unsigned long end);
 121 extern unsigned long name_cache_init(unsigned long start, unsigned long end);
 122 
 123 typedef char buffer_block[BLOCK_SIZE];
 124 
 125 /* bh state bits */
 126 #define BH_Uptodate     0       /* 1 if the buffer contains valid data */
 127 #define BH_Dirty        1       /* 1 if the buffer is dirty */
 128 #define BH_Lock         2       /* 1 if the buffer is locked */
 129 #define BH_Req          3       /* 0 if the buffer has been invalidated */
 130 #define BH_Touched      4       /* 1 if the buffer has been touched (aging) */
 131 #define BH_Has_aged     5       /* 1 if the buffer has been aged (aging) */
 132 #define BH_Protected    6       /* 1 if the buffer is protected */
 133 
 134 struct buffer_head {
 135         char * b_data;                  /* pointer to data block (1024 bytes) */
 136         unsigned long b_size;           /* block size */
 137         unsigned long b_blocknr;        /* block number */
 138         kdev_t b_dev;                   /* device (B_FREE = free) */
 139         unsigned long b_state;          /* buffer state bitmap (see above) */
 140         unsigned int b_count;           /* users using this block */
 141         unsigned int b_list;            /* List that this buffer appears */
 142         unsigned long b_flushtime;      /* Time when this (dirty) buffer
 143                                          * should be written */
 144         unsigned long b_lru_time;       /* Time when this buffer was 
 145                                          * last used. */
 146         struct wait_queue * b_wait;
 147         struct buffer_head * b_prev;            /* doubly linked list of hash-queue */
 148         struct buffer_head * b_next;
 149         struct buffer_head * b_prev_free;       /* doubly linked list of buffers */
 150         struct buffer_head * b_next_free;
 151         struct buffer_head * b_this_page;       /* circular list of buffers in one page */
 152         struct buffer_head * b_reqnext;         /* request queue */
 153 };
 154 
 155 static inline int buffer_uptodate(struct buffer_head * bh)
     /*  */
 156 {
 157         return test_bit(BH_Uptodate, &bh->b_state);
 158 }       
 159 
 160 static inline int buffer_dirty(struct buffer_head * bh)
     /*  */
 161 {
 162         return test_bit(BH_Dirty, &bh->b_state);
 163 }
 164 
 165 static inline int buffer_locked(struct buffer_head * bh)
     /*  */
 166 {
 167         return test_bit(BH_Lock, &bh->b_state);
 168 }
 169 
 170 static inline int buffer_req(struct buffer_head * bh)
     /*  */
 171 {
 172         return test_bit(BH_Req, &bh->b_state);
 173 }
 174 
 175 static inline int buffer_touched(struct buffer_head * bh)
     /*  */
 176 {
 177         return test_bit(BH_Touched, &bh->b_state);
 178 }
 179 
 180 static inline int buffer_has_aged(struct buffer_head * bh)
     /*  */
 181 {
 182         return test_bit(BH_Has_aged, &bh->b_state);
 183 }
 184 
 185 static inline int buffer_protected(struct buffer_head * bh)
     /*  */
 186 {
 187         return test_bit(BH_Protected, &bh->b_state);
 188 }
 189 
 190 #include <linux/pipe_fs_i.h>
 191 #include <linux/minix_fs_i.h>
 192 #include <linux/ext_fs_i.h>
 193 #include <linux/ext2_fs_i.h>
 194 #include <linux/hpfs_fs_i.h>
 195 #include <linux/msdos_fs_i.h>
 196 #include <linux/umsdos_fs_i.h>
 197 #include <linux/iso_fs_i.h>
 198 #include <linux/nfs_fs_i.h>
 199 #include <linux/xia_fs_i.h>
 200 #include <linux/sysv_fs_i.h>
 201 
 202 /*
 203  * Attribute flags.  These should be or-ed together to figure out what
 204  * has been changed!
 205  */
 206 #define ATTR_MODE       1
 207 #define ATTR_UID        2
 208 #define ATTR_GID        4
 209 #define ATTR_SIZE       8
 210 #define ATTR_ATIME      16
 211 #define ATTR_MTIME      32
 212 #define ATTR_CTIME      64
 213 #define ATTR_ATIME_SET  128
 214 #define ATTR_MTIME_SET  256
 215 
 216 /*
 217  * This is the Inode Attributes structure, used for notify_change().  It
 218  * uses the above definitions as flags, to know which values have changed.
 219  * Also, in this manner, a Filesystem can look at only the values it cares
 220  * about.  Basically, these are the attributes that the VFS layer can
 221  * request to change from the FS layer.
 222  *
 223  * Derek Atkins <warlord@MIT.EDU> 94-10-20
 224  */
 225 struct iattr {
 226         unsigned int    ia_valid;
 227         umode_t         ia_mode;
 228         uid_t           ia_uid;
 229         gid_t           ia_gid;
 230         off_t           ia_size;
 231         time_t          ia_atime;
 232         time_t          ia_mtime;
 233         time_t          ia_ctime;
 234 };
 235 
 236 #include <linux/quota.h>
 237 
 238 struct inode {
 239         kdev_t          i_dev;
 240         unsigned long   i_ino;
 241         umode_t         i_mode;
 242         nlink_t         i_nlink;
 243         uid_t           i_uid;
 244         gid_t           i_gid;
 245         kdev_t          i_rdev;
 246         off_t           i_size;
 247         time_t          i_atime;
 248         time_t          i_mtime;
 249         time_t          i_ctime;
 250         unsigned long   i_blksize;
 251         unsigned long   i_blocks;
 252         unsigned long   i_version;
 253         struct semaphore i_sem;
 254         struct inode_operations *i_op;
 255         struct super_block *i_sb;
 256         struct wait_queue *i_wait;
 257         struct file_lock *i_flock;
 258         struct vm_area_struct *i_mmap;
 259         struct dquot *i_dquot[MAXQUOTAS];
 260         struct inode *i_next, *i_prev;
 261         struct inode *i_hash_next, *i_hash_prev;
 262         struct inode *i_bound_to, *i_bound_by;
 263         struct inode *i_mount;
 264         unsigned short i_count;
 265         unsigned short i_flags;
 266         unsigned char i_lock;
 267         unsigned char i_dirt;
 268         unsigned char i_pipe;
 269         unsigned char i_sock;
 270         unsigned char i_seek;
 271         unsigned char i_update;
 272         unsigned short i_writecount;
 273         union {
 274                 struct pipe_inode_info pipe_i;
 275                 struct minix_inode_info minix_i;
 276                 struct ext_inode_info ext_i;
 277                 struct ext2_inode_info ext2_i;
 278                 struct hpfs_inode_info hpfs_i;
 279                 struct msdos_inode_info msdos_i;
 280                 struct umsdos_inode_info umsdos_i;
 281                 struct iso_inode_info isofs_i;
 282                 struct nfs_inode_info nfs_i;
 283                 struct xiafs_inode_info xiafs_i;
 284                 struct sysv_inode_info sysv_i;
 285                 struct socket socket_i;
 286                 void * generic_ip;
 287         } u;
 288 };
 289 
 290 struct file {
 291         mode_t f_mode;
 292         loff_t f_pos;
 293         unsigned short f_flags;
 294         unsigned short f_count;
 295         off_t f_reada;
 296         struct file *f_next, *f_prev;
 297         int f_owner;            /* pid or -pgrp where SIGIO should be sent */
 298         struct inode * f_inode;
 299         struct file_operations * f_op;
 300         unsigned long f_version;
 301         void *private_data;     /* needed for tty driver, and maybe others */
 302 };
 303 
 304 struct file_lock {
 305         struct file_lock *fl_next;      /* singly linked list for this inode  */
 306         struct file_lock *fl_nextlink;  /* doubly linked list of all locks */
 307         struct file_lock *fl_prevlink;  /* used to simplify lock removal */
 308         struct file_lock *fl_block;
 309         struct task_struct *fl_owner;
 310         struct wait_queue *fl_wait;
 311         struct file *fl_file;
 312         char fl_flags;
 313         char fl_type;
 314         off_t fl_start;
 315         off_t fl_end;
 316 };
 317 
 318 struct fasync_struct {
 319         int    magic;
 320         struct fasync_struct    *fa_next; /* singly linked list */
 321         struct file             *fa_file;
 322 };
 323 
 324 #define FASYNC_MAGIC 0x4601
 325 
 326 extern int fasync_helper(struct inode *, struct file *, int, struct fasync_struct **);
 327 
 328 #include <linux/minix_fs_sb.h>
 329 #include <linux/ext_fs_sb.h>
 330 #include <linux/ext2_fs_sb.h>
 331 #include <linux/hpfs_fs_sb.h>
 332 #include <linux/msdos_fs_sb.h>
 333 #include <linux/iso_fs_sb.h>
 334 #include <linux/nfs_fs_sb.h>
 335 #include <linux/xia_fs_sb.h>
 336 #include <linux/sysv_fs_sb.h>
 337 
 338 struct super_block {
 339         kdev_t s_dev;
 340         unsigned long s_blocksize;
 341         unsigned char s_blocksize_bits;
 342         unsigned char s_lock;
 343         unsigned char s_rd_only;
 344         unsigned char s_dirt;
 345         struct file_system_type *s_type;
 346         struct super_operations *s_op;
 347         struct dquot_operations *dq_op;
 348         unsigned long s_flags;
 349         unsigned long s_magic;
 350         unsigned long s_time;
 351         struct inode * s_covered;
 352         struct inode * s_mounted;
 353         struct wait_queue * s_wait;
 354         union {
 355                 struct minix_sb_info minix_sb;
 356                 struct ext_sb_info ext_sb;
 357                 struct ext2_sb_info ext2_sb;
 358                 struct hpfs_sb_info hpfs_sb;
 359                 struct msdos_sb_info msdos_sb;
 360                 struct isofs_sb_info isofs_sb;
 361                 struct nfs_sb_info nfs_sb;
 362                 struct xiafs_sb_info xiafs_sb;
 363                 struct sysv_sb_info sysv_sb;
 364                 void *generic_sbp;
 365         } u;
 366 };
 367 
 368 /*
 369  * This is the "filldir" function type, used by readdir() to let
 370  * the kernel specify what kind of dirent layout it wants to have.
 371  * This allows the kernel to read directories into kernel space or
 372  * to have different dirent layouts depending on the binary type.
 373  */
 374 typedef int (*filldir_t)(void *, const char *, int, off_t, ino_t);
 375         
 376 struct file_operations {
 377         int (*lseek) (struct inode *, struct file *, off_t, int);
 378         int (*read) (struct inode *, struct file *, char *, int);
 379         int (*write) (struct inode *, struct file *, const char *, int);
 380         int (*readdir) (struct inode *, struct file *, void *, filldir_t);
 381         int (*select) (struct inode *, struct file *, int, select_table *);
 382         int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
 383         int (*mmap) (struct inode *, struct file *, struct vm_area_struct *);
 384         int (*open) (struct inode *, struct file *);
 385         void (*release) (struct inode *, struct file *);
 386         int (*fsync) (struct inode *, struct file *);
 387         int (*fasync) (struct inode *, struct file *, int);
 388         int (*check_media_change) (kdev_t dev);
 389         int (*revalidate) (kdev_t dev);
 390 };
 391 
 392 struct inode_operations {
 393         struct file_operations * default_file_ops;
 394         int (*create) (struct inode *,const char *,int,int,struct inode **);
 395         int (*lookup) (struct inode *,const char *,int,struct inode **);
 396         int (*link) (struct inode *,struct inode *,const char *,int);
 397         int (*unlink) (struct inode *,const char *,int);
 398         int (*symlink) (struct inode *,const char *,int,const char *);
 399         int (*mkdir) (struct inode *,const char *,int,int);
 400         int (*rmdir) (struct inode *,const char *,int);
 401         int (*mknod) (struct inode *,const char *,int,int,int);
 402         int (*rename) (struct inode *,const char *,int,struct inode *,const char *,int);
 403         int (*readlink) (struct inode *,char *,int);
 404         int (*follow_link) (struct inode *,struct inode *,int,int,struct inode **);
 405         int (*bmap) (struct inode *,int);
 406         void (*truncate) (struct inode *);
 407         int (*permission) (struct inode *, int);
 408         int (*smap) (struct inode *,int);
 409 };
 410 
 411 struct super_operations {
 412         void (*read_inode) (struct inode *);
 413         int (*notify_change) (struct inode *, struct iattr *);
 414         void (*write_inode) (struct inode *);
 415         void (*put_inode) (struct inode *);
 416         void (*put_super) (struct super_block *);
 417         void (*write_super) (struct super_block *);
 418         void (*statfs) (struct super_block *, struct statfs *, int);
 419         int (*remount_fs) (struct super_block *, int *, char *);
 420 };
 421 
 422 struct dquot_operations {
 423         void (*initialize) (struct inode *, short);
 424         void (*drop) (struct inode *);
 425         int (*alloc_block) (const struct inode *, unsigned long);
 426         int (*alloc_inode) (const struct inode *, unsigned long);
 427         void (*free_block) (const struct inode *, unsigned long);
 428         void (*free_inode) (const struct inode *, unsigned long);
 429         int (*transfer) (struct inode *, struct iattr *, char);
 430 };
 431 
 432 struct file_system_type {
 433         struct super_block *(*read_super) (struct super_block *, void *, int);
 434         const char *name;
 435         int requires_dev;
 436         struct file_system_type * next;
 437 };
 438 
 439 extern int register_filesystem(struct file_system_type *);
 440 extern int unregister_filesystem(struct file_system_type *);
 441 
 442 asmlinkage int sys_open(const char *, int, int);
 443 asmlinkage int sys_close(unsigned int);         /* yes, it's really unsigned */
 444 
 445 extern void kill_fasync(struct fasync_struct *fa, int sig);
 446 
 447 extern int getname(const char * filename, char **result);
 448 extern void putname(char * name);
 449 
 450 extern int register_blkdev(unsigned int, const char *, struct file_operations *);
 451 extern int unregister_blkdev(unsigned int major, const char * name);
 452 extern int blkdev_open(struct inode * inode, struct file * filp);
 453 extern struct file_operations def_blk_fops;
 454 extern struct inode_operations blkdev_inode_operations;
 455 
 456 extern int register_chrdev(unsigned int, const char *, struct file_operations *);
 457 extern int unregister_chrdev(unsigned int major, const char * name);
 458 extern int chrdev_open(struct inode * inode, struct file * filp);
 459 extern struct file_operations def_chr_fops;
 460 extern struct inode_operations chrdev_inode_operations;
 461 
 462 extern void init_fifo(struct inode * inode);
 463 
 464 extern struct file_operations connecting_fifo_fops;
 465 extern struct file_operations read_fifo_fops;
 466 extern struct file_operations write_fifo_fops;
 467 extern struct file_operations rdwr_fifo_fops;
 468 extern struct file_operations read_pipe_fops;
 469 extern struct file_operations write_pipe_fops;
 470 extern struct file_operations rdwr_pipe_fops;
 471 
 472 extern struct file_system_type *get_fs_type(const char *name);
 473 
 474 extern int fs_may_mount(kdev_t dev);
 475 extern int fs_may_umount(kdev_t dev, struct inode * mount_root);
 476 extern int fs_may_remount_ro(kdev_t dev);
 477 
 478 extern struct file *first_file;
 479 extern int nr_files;
 480 extern struct super_block super_blocks[NR_SUPER];
 481 
 482 extern int shrink_buffers(unsigned int priority, unsigned long limit);
 483 extern void refile_buffer(struct buffer_head * buf);
 484 extern void set_writetime(struct buffer_head * buf, int flag);
 485 extern void refill_freelist(int size);
 486 
 487 extern struct buffer_head ** buffer_pages;
 488 extern int nr_buffers;
 489 extern int buffermem;
 490 extern int nr_buffer_heads;
 491 
 492 #define BUF_CLEAN 0
 493 #define BUF_UNSHARED 1 /* Buffers that were shared but are not any more */
 494 #define BUF_LOCKED 2   /* Buffers scheduled for write */
 495 #define BUF_LOCKED1 3  /* Supers, inodes */
 496 #define BUF_DIRTY 4    /* Dirty buffers, not yet scheduled for write */
 497 #define BUF_SHARED 5   /* Buffers shared */
 498 #define NR_LIST 6
 499 
 500 extern inline void mark_buffer_uptodate(struct buffer_head * bh, int on)
     /*  */
 501 {
 502         if (on)
 503                 set_bit(BH_Uptodate, &bh->b_state);
 504         else
 505                 clear_bit(BH_Uptodate, &bh->b_state);
 506 }
 507 
 508 extern inline void mark_buffer_clean(struct buffer_head * bh)
     /*  */
 509 {
 510         if (clear_bit(BH_Dirty, &bh->b_state)) {
 511                 if (bh->b_list == BUF_DIRTY)
 512                         refile_buffer(bh);
 513         }
 514 }
 515 
 516 extern inline void mark_buffer_dirty(struct buffer_head * bh, int flag)
     /*  */
 517 {
 518         if (!set_bit(BH_Dirty, &bh->b_state)) {
 519                 set_writetime(bh, flag);
 520                 if (bh->b_list != BUF_DIRTY)
 521                         refile_buffer(bh);
 522         }
 523 }
 524 
 525 extern int check_disk_change(kdev_t dev);
 526 extern void invalidate_inodes(kdev_t dev);
 527 extern void invalidate_buffers(kdev_t dev);
 528 extern int floppy_is_wp(int minor);
 529 extern void sync_inodes(kdev_t dev);
 530 extern void sync_dev(kdev_t dev);
 531 extern int fsync_dev(kdev_t dev);
 532 extern void sync_supers(kdev_t dev);
 533 extern int bmap(struct inode * inode,int block);
 534 extern int notify_change(struct inode *, struct iattr *);
 535 extern int namei(const char * pathname, struct inode ** res_inode);
 536 extern int lnamei(const char * pathname, struct inode ** res_inode);
 537 extern int permission(struct inode * inode,int mask);
 538 extern int get_write_access(struct inode *inode);
 539 extern void put_write_access(struct inode *inode);
 540 extern int open_namei(const char * pathname, int flag, int mode,
 541         struct inode ** res_inode, struct inode * base);
 542 extern int do_mknod(const char * filename, int mode, dev_t dev);
 543 extern int do_pipe(int *);
 544 extern void iput(struct inode * inode);
 545 extern struct inode * __iget(struct super_block * sb,int nr,int crsmnt);
 546 extern struct inode * get_empty_inode(void);
 547 extern void insert_inode_hash(struct inode *);
 548 extern void clear_inode(struct inode *);
 549 extern struct inode * get_pipe_inode(void);
 550 extern struct file * get_empty_filp(void);
 551 extern int close_fp(struct file *filp);
 552 extern struct buffer_head * get_hash_table(kdev_t dev, int block, int size);
 553 extern struct buffer_head * getblk(kdev_t dev, int block, int size);
 554 extern void ll_rw_block(int rw, int nr, struct buffer_head * bh[]);
 555 extern void ll_rw_page(int rw, kdev_t dev, unsigned long nr, char * buffer);
 556 extern void ll_rw_swap_file(int rw, kdev_t dev, unsigned int *b, int nb, char *buffer);
 557 extern int is_read_only(kdev_t dev);
 558 extern void __brelse(struct buffer_head *buf);
 559 extern inline void brelse(struct buffer_head *buf)
     /*  */
 560 {
 561         if (buf)
 562                 __brelse(buf);
 563 }
 564 extern void __bforget(struct buffer_head *buf);
 565 extern inline void bforget(struct buffer_head *buf)
     /*  */
 566 {
 567         if (buf)
 568                 __bforget(buf);
 569 }
 570 extern void set_blocksize(kdev_t dev, int size);
 571 extern struct buffer_head * bread(kdev_t dev, int block, int size);
 572 extern unsigned long bread_page(unsigned long addr,kdev_t dev,int b[],int size,int no_share);
 573 extern void bwrite_page(unsigned long addr,kdev_t dev,int b[],int size);
 574 extern struct buffer_head * breada(kdev_t dev,int block, int size, 
 575                                    unsigned int pos, unsigned int filesize);
 576 extern void put_super(kdev_t dev);
 577 unsigned long generate_cluster(kdev_t dev, int b[], int size);
 578 extern kdev_t ROOT_DEV;
 579 
 580 extern void show_buffers(void);
 581 extern void mount_root(void);
 582 
 583 extern int char_read(struct inode *, struct file *, char *, int);
 584 extern int block_read(struct inode *, struct file *, char *, int);
 585 extern int read_ahead[];
 586 
 587 extern int char_write(struct inode *, struct file *, const char *, int);
 588 extern int block_write(struct inode *, struct file *, const char *, int);
 589 
 590 extern int generic_mmap(struct inode *, struct file *, struct vm_area_struct *);
 591 
 592 extern int block_fsync(struct inode *, struct file *);
 593 extern int file_fsync(struct inode *, struct file *);
 594 
 595 extern void dcache_add(struct inode *, const char *, int, unsigned long);
 596 extern int dcache_lookup(struct inode *, const char *, int, unsigned long *);
 597 
 598 extern int inode_change_ok(struct inode *, struct iattr *);
 599 extern void inode_setattr(struct inode *, struct iattr *);
 600 
 601 extern inline struct inode * iget(struct super_block * sb,int nr)
     /*  */
 602 {
 603         return __iget(sb, nr, 1);
 604 }
 605 
 606 #endif /* __KERNEL__ */
 607 
 608 #endif

/* */