include/linux/fs.h

   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/linkage.h>
  11 #include <linux/limits.h>
  12 #include <linux/wait.h>
  13 #include <linux/types.h>
  14 #include <linux/vfs.h>
  15 #include <linux/net.h>
  16 #include <linux/kdev_t.h>
  17 #include <linux/ioctl.h>
  18 #include <linux/list.h>
  19 #include <linux/dcache.h>
  20 #include <linux/stat.h>
  21 #include <linux/cache.h>
  22 #include <linux/stddef.h>
  23 #include <linux/string.h>
  24
  25 #include <asm/atomic.h>
  26 #include <asm/bitops.h>
  27
  28 struct poll_table_struct;
  29
  30
  31 /*
  32  * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
  33  * the file limit at runtime and only root can increase the per-process
  34  * nr_file rlimit, so it's safe to set up a ridiculously high absolute
  35  * upper limit on files-per-process.
  36  *
  37  * Some programs (notably those using select()) may have to be
  38  * recompiled to take full advantage of the new limits..
  39  */
  40
  41 /* Fixed constants first: */
  42 #undef NR_OPEN
  43 #define NR_OPEN (1024*1024)     /* Absolute upper limit on fd num */
  44 #define INR_OPEN 1024           /* Initial setting for nfile rlimits */
  45
  46 #define BLOCK_SIZE_BITS 10
  47 #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
  48
  49 /* And dynamically-tunable limits and defaults: */
  50 extern int max_files, nr_files, nr_free_files;
  51 extern int max_super_blocks, nr_super_blocks;
  52
  53 #define NR_FILE  8192   /* this can well be larger on a larger system */
  54 #define NR_RESERVED_FILES 10 /* reserved for root */
  55 #define NR_SUPER 256
  56
  57 #define MAY_EXEC 1
  58 #define MAY_WRITE 2
  59 #define MAY_READ 4
  60
  61 #define FMODE_READ 1
  62 #define FMODE_WRITE 2
  63
  64 #define READ 0
  65 #define WRITE 1
  66 #define READA 2         /* read-ahead  - don't block if no resources */
  67 #define SPECIAL 4       /* For non-blockdevice requests in request queue */
  68
  69 #define WRITERAW 5      /* raw write - don't play with buffer lists */
  70
  71 #define NIL_FILP        ((struct file *)0)
  72 #define SEL_IN          1
  73 #define SEL_OUT         2
  74 #define SEL_EX          4
  75
  76 /* public flags for file_system_type */
  77 #define FS_REQUIRES_DEV 1
  78 #define FS_NO_DCACHE    2 /* Only dcache the necessary things. */
  79 #define FS_NO_PRELIM    4 /* prevent preloading of dentries, even if
  80                            * FS_NO_DCACHE is not set.
  81                            */
  82
  83 /*
  84  * These are the fs-independent mount-flags: up to 16 flags are supported
  85  */
  86 #define MS_RDONLY        1      /* Mount read-only */
  87 #define MS_NOSUID        2      /* Ignore suid and sgid bits */
  88 #define MS_NODEV         4      /* Disallow access to device special files */
  89 #define MS_NOEXEC        8      /* Disallow program execution */
  90 #define MS_SYNCHRONOUS  16      /* Writes are synced at once */
  91 #define MS_REMOUNT      32      /* Alter flags of a mounted FS */
  92 #define MS_MANDLOCK     64      /* Allow mandatory locks on an FS */
  93 #define S_QUOTA         128     /* Quota initialized for file/directory/symlink */
  94 #define S_APPEND        256     /* Append-only file */
  95 #define S_IMMUTABLE     512     /* Immutable file */
  96 #define MS_NOATIME      1024    /* Do not update access times. */
  97 #define MS_NODIRATIME   2048    /* Do not update directory access times */
  98
  99 #define MS_ODD_RENAME   32768   /* Temporary stuff; will go away as soon
 100                                   * as nfs_rename() will be cleaned up
 101                                   */
 102
 103 /*
 104  * Flags that can be altered by MS_REMOUNT
 105  */
 106 #define MS_RMT_MASK     (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|\
 107                         MS_SYNCHRONOUS|MS_MANDLOCK|MS_NOATIME|MS_NODIRATIME)
 108
 109 /*
 110  * Magic mount flag number. Has to be or-ed to the flag values.
 111  */
 112 #define MS_MGC_VAL 0xC0ED0000   /* magic flag number to indicate "new" flags */
 113 #define MS_MGC_MSK 0xffff0000   /* magic flag number mask */
 114
 115 /*
 116  * Note that nosuid etc flags are inode-specific: setting some file-system
 117  * flags just means all the inodes inherit those flags by default. It might be
 118  * possible to override it selectively if you really wanted to with some
 119  * ioctl() that is not currently implemented.
 120  *
 121  * Exception: MS_RDONLY is always applied to the entire file system.
 122  *
 123  * Unfortunately, it is possible to change a filesystems flags with it mounted
 124  * with files in use.  This means that all of the inodes will not have their
 125  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
 126  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
 127  */
 128 #define __IS_FLG(inode,flg) (((inode)->i_sb && (inode)->i_sb->s_flags & (flg)) \
 129                                 || (inode)->i_flags & (flg))
 130
 131 #define IS_RDONLY(inode) (((inode)->i_sb) && ((inode)->i_sb->s_flags & MS_RDONLY))
 132 #define IS_NOSUID(inode)        __IS_FLG(inode, MS_NOSUID)
 133 #define IS_NODEV(inode)         __IS_FLG(inode, MS_NODEV)
 134 #define IS_NOEXEC(inode)        __IS_FLG(inode, MS_NOEXEC)
 135 #define IS_SYNC(inode)          __IS_FLG(inode, MS_SYNCHRONOUS)
 136 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
 137
 138 #define IS_QUOTAINIT(inode)     ((inode)->i_flags & S_QUOTA)
 139 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
 140 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
 141 #define IS_NOATIME(inode)       __IS_FLG(inode, MS_NOATIME)
 142 #define IS_NODIRATIME(inode)    __IS_FLG(inode, MS_NODIRATIME)
 143
 144
 145 /* the read-only stuff doesn't really belong here, but any other place is
 146    probably as bad and I don't want to create yet another include file. */
 147
 148 #define BLKROSET   _IO(0x12,93) /* set device read-only (0 = read-write) */
 149 #define BLKROGET   _IO(0x12,94) /* get read-only status (0 = read_write) */
 150 #define BLKRRPART  _IO(0x12,95) /* re-read partition table */
 151 #define BLKGETSIZE _IO(0x12,96) /* return device size */
 152 #define BLKFLSBUF  _IO(0x12,97) /* flush buffer cache */
 153 #define BLKRASET   _IO(0x12,98) /* Set read ahead for block device */
 154 #define BLKRAGET   _IO(0x12,99) /* get current read ahead setting */
 155 #define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
 156 #define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
 157 #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
 158 #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
 159 #define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
 160 #if 0
 161 #define BLKPG      _IO(0x12,105)/* See blkpg.h */
 162 #define BLKELVGET   _IO(0x12,106)/* elevator get */
 163 #define BLKELVSET   _IO(0x12,107)/* elevator set */
 164 /* This was here just to show that the number is taken -
 165    probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
 166 #endif
 167
 168
 169 #define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
 170 #define FIBMAP     _IO(0x00,1)  /* bmap access */
 171 #define FIGETBSZ   _IO(0x00,2)  /* get the block size used for bmap */
 172
 173 #ifdef __KERNEL__
 174
 175 #include <asm/semaphore.h>
 176 #include <asm/byteorder.h>
 177
 178 extern void update_atime (struct inode *);
 179 #define UPDATE_ATIME(inode) update_atime (inode)
 180
 181 extern void buffer_init(unsigned long);
 182 extern void inode_init(void);
 183 extern void file_table_init(void);
 184 extern void dcache_init(void);
 185
 186 /* bh state bits */
 187 #define BH_Uptodate     0       /* 1 if the buffer contains valid data */
 188 #define BH_Dirty        1       /* 1 if the buffer is dirty */
 189 #define BH_Lock         2       /* 1 if the buffer is locked */
 190 #define BH_Req          3       /* 0 if the buffer has been invalidated */
 191 #define BH_Mapped       4       /* 1 if the buffer has a disk mapping */
 192 #define BH_New          5       /* 1 if the buffer is new and not yet written out */
 193 #define BH_Protected    6       /* 1 if the buffer is protected */
 194
 195 /*
 196  * Try to keep the most commonly used fields in single cache lines (16
 197  * bytes) to improve performance.  This ordering should be
 198  * particularly beneficial on 32-bit processors.
 199  *
 200  * We use the first 16 bytes for the data which is used in searches
 201  * over the block hash lists (ie. getblk() and friends).
 202  *
 203  * The second 16 bytes we use for lru buffer scans, as used by
 204  * sync_buffers() and refill_freelist().  -- sct
 205  */
 206 struct buffer_head {
 207         /* First cache line: */
 208         struct buffer_head *b_next;     /* Hash queue list */
 209         unsigned long b_blocknr;        /* block number */
 210         unsigned short b_size;          /* block size */
 211         unsigned short b_list;          /* List that this buffer appears */
 212         kdev_t b_dev;                   /* device (B_FREE = free) */
 213
 214         atomic_t b_count;               /* users using this block */
 215         kdev_t b_rdev;                  /* Real device */
 216         unsigned long b_state;          /* buffer state bitmap (see above) */
 217         unsigned long b_flushtime;      /* Time when (dirty) buffer should be written */
 218
 219         struct buffer_head *b_next_free;/* lru/free list linkage */
 220         struct buffer_head *b_prev_free;/* doubly linked list of buffers */
 221         struct buffer_head *b_this_page;/* circular list of buffers in one page */
 222         struct buffer_head *b_reqnext;  /* request queue */
 223
 224         struct buffer_head **b_pprev;   /* doubly linked list of hash-queue */
 225         char * b_data;                  /* pointer to data block (512 byte) */
 226         struct page *b_page;            /* the page this bh is mapped to */
 227         void (*b_end_io)(struct buffer_head *bh, int uptodate); /* I/O completion */
 228         void *b_dev_id;
 229
 230         unsigned long b_rsector;        /* Real buffer location on disk */
 231         wait_queue_head_t b_wait;
 232         struct kiobuf * b_kiobuf;       /* kiobuf which owns this IO */
 233 };
 234
 235 typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
 236 void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
 237
 238 #define __buffer_state(bh, state)       (((bh)->b_state & (1UL << BH_##state)) != 0)
 239
 240 #define buffer_uptodate(bh)     __buffer_state(bh,Uptodate)
 241 #define buffer_dirty(bh)        __buffer_state(bh,Dirty)
 242 #define buffer_locked(bh)       __buffer_state(bh,Lock)
 243 #define buffer_req(bh)          __buffer_state(bh,Req)
 244 #define buffer_mapped(bh)       __buffer_state(bh,Mapped)
 245 #define buffer_new(bh)          __buffer_state(bh,New)
 246 #define buffer_protected(bh)    __buffer_state(bh,Protected)
 247
 248 #define bh_offset(bh)           ((unsigned long)(bh)->b_data & ~PAGE_MASK)
 249
 250 extern void set_bh_page(struct buffer_head *bh, struct page *page, unsigned long offset);
 251
 252 #define touch_buffer(bh)        set_bit(PG_referenced, &bh->b_page->flags)
 253
 254
 255 #include <linux/pipe_fs_i.h>
 256 #include <linux/minix_fs_i.h>
 257 #include <linux/ext2_fs_i.h>
 258 #include <linux/hpfs_fs_i.h>
 259 #include <linux/ntfs_fs_i.h>
 260 #include <linux/msdos_fs_i.h>
 261 #include <linux/umsdos_fs_i.h>
 262 #include <linux/iso_fs_i.h>
 263 #include <linux/nfs_fs_i.h>
 264 #include <linux/sysv_fs_i.h>
 265 #include <linux/affs_fs_i.h>
 266 #include <linux/ufs_fs_i.h>
 267 #include <linux/efs_fs_i.h>
 268 #include <linux/coda_fs_i.h>
 269 #include <linux/romfs_fs_i.h>
 270 #include <linux/smb_fs_i.h>
 271 #include <linux/hfs_fs_i.h>
 272 #include <linux/adfs_fs_i.h>
 273 #include <linux/qnx4_fs_i.h>
 274 #include <linux/bfs_fs_i.h>
 275 #include <linux/udf_fs_i.h>
 276 #include <linux/ncp_fs_i.h>
 277 #include <linux/proc_fs_i.h>
 278 #include <linux/usbdev_fs_i.h>
 279
 280 /*
 281  * Attribute flags.  These should be or-ed together to figure out what
 282  * has been changed!
 283  */
 284 #define ATTR_MODE       1
 285 #define ATTR_UID        2
 286 #define ATTR_GID        4
 287 #define ATTR_SIZE       8
 288 #define ATTR_ATIME      16
 289 #define ATTR_MTIME      32
 290 #define ATTR_CTIME      64
 291 #define ATTR_ATIME_SET  128
 292 #define ATTR_MTIME_SET  256
 293 #define ATTR_FORCE      512     /* Not a change, but a change it */
 294 #define ATTR_ATTR_FLAG  1024
 295
 296 /*
 297  * This is the Inode Attributes structure, used for notify_change().  It
 298  * uses the above definitions as flags, to know which values have changed.
 299  * Also, in this manner, a Filesystem can look at only the values it cares
 300  * about.  Basically, these are the attributes that the VFS layer can
 301  * request to change from the FS layer.
 302  *
 303  * Derek Atkins <warlord@MIT.EDU> 94-10-20
 304  */
 305 struct iattr {
 306         unsigned int    ia_valid;
 307         umode_t         ia_mode;
 308         uid_t           ia_uid;
 309         gid_t           ia_gid;
 310         loff_t          ia_size;
 311         time_t          ia_atime;
 312         time_t          ia_mtime;
 313         time_t          ia_ctime;
 314         unsigned int    ia_attr_flags;
 315 };
 316
 317 /*
 318  * This is the inode attributes flag definitions
 319  */
 320 #define ATTR_FLAG_SYNCRONOUS    1       /* Syncronous write */
 321 #define ATTR_FLAG_NOATIME       2       /* Don't update atime */
 322 #define ATTR_FLAG_APPEND        4       /* Append-only file */
 323 #define ATTR_FLAG_IMMUTABLE     8       /* Immutable file */
 324 #define ATTR_FLAG_NODIRATIME    16      /* Don't update atime for directory */
 325
 326 /*
 327  * Includes for diskquotas and mount structures.
 328  */
 329 #include <linux/quota.h>
 330 #include <linux/mount.h>
 331
 332 /*
 333  * oh the beauties of C type declarations.
 334  */
 335 struct page;
 336 struct address_space;
 337
 338 struct address_space_operations {
 339         int (*writepage) (struct dentry *, struct page *);
 340         int (*readpage)(struct dentry *, struct page *);
 341         int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
 342         int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
 343         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
 344         int (*bmap)(struct address_space *, long);
 345 };
 346
 347 struct address_space {
 348         struct list_head        pages;          /* list of pages */
 349         unsigned long           nrpages;        /* number of pages */
 350         struct address_space_operations *a_ops; /* methods */
 351         void                    *host;          /* owner: inode, block_device */
 352         struct vm_area_struct   *i_mmap;        /* list of mappings */
 353         spinlock_t              i_shared_lock;  /* and spinlock protecting it */
 354 };
 355
 356 struct block_device {
 357         struct list_head        bd_hash;
 358         atomic_t                bd_count;
 359 /*      struct address_space    bd_data; */
 360         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
 361         atomic_t                bd_openers;
 362         const struct block_device_operations *bd_op;
 363         struct semaphore        bd_sem; /* open/close mutex */
 364 };
 365
 366 struct inode {
 367         struct list_head        i_hash;
 368         struct list_head        i_list;
 369         struct list_head        i_dentry;
 370
 371         unsigned long           i_ino;
 372         unsigned int            i_count;
 373         kdev_t                  i_dev;
 374         umode_t                 i_mode;
 375         nlink_t                 i_nlink;
 376         uid_t                   i_uid;
 377         gid_t                   i_gid;
 378         kdev_t                  i_rdev;
 379         loff_t                  i_size;
 380         time_t                  i_atime;
 381         time_t                  i_mtime;
 382         time_t                  i_ctime;
 383         unsigned long           i_blksize;
 384         unsigned long           i_blocks;
 385         unsigned long           i_version;
 386         struct semaphore        i_sem;
 387         struct semaphore        i_zombie;
 388         struct inode_operations *i_op;
 389         struct file_operations  *i_fop; /* former ->i_op->default_file_ops */
 390         struct super_block      *i_sb;
 391         wait_queue_head_t       i_wait;
 392         struct file_lock        *i_flock;
 393         struct address_space    *i_mapping;
 394         struct address_space    i_data;
 395         struct dquot            *i_dquot[MAXQUOTAS];
 396         struct pipe_inode_info  *i_pipe;
 397         struct block_device     *i_bdev;
 398
 399         unsigned long           i_state;
 400
 401         unsigned int            i_flags;
 402         unsigned char           i_sock;
 403
 404         atomic_t                i_writecount;
 405         unsigned int            i_attr_flags;
 406         __u32                   i_generation;
 407         union {
 408                 struct minix_inode_info         minix_i;
 409                 struct ext2_inode_info          ext2_i;
 410                 struct hpfs_inode_info          hpfs_i;
 411                 struct ntfs_inode_info          ntfs_i;
 412                 struct msdos_inode_info         msdos_i;
 413                 struct umsdos_inode_info        umsdos_i;
 414                 struct iso_inode_info           isofs_i;
 415                 struct nfs_inode_info           nfs_i;
 416                 struct sysv_inode_info          sysv_i;
 417                 struct affs_inode_info          affs_i;
 418                 struct ufs_inode_info           ufs_i;
 419                 struct efs_inode_info           efs_i;
 420                 struct romfs_inode_info         romfs_i;
 421                 struct coda_inode_info          coda_i;
 422                 struct smb_inode_info           smbfs_i;
 423                 struct hfs_inode_info           hfs_i;
 424                 struct adfs_inode_info          adfs_i;
 425                 struct qnx4_inode_info          qnx4_i;
 426                 struct bfs_inode_info           bfs_i;
 427                 struct udf_inode_info           udf_i;
 428                 struct ncp_inode_info           ncpfs_i;
 429                 struct proc_inode_info          proc_i;
 430                 struct socket                   socket_i;
 431                 struct usbdev_inode_info        usbdev_i;
 432                 void                            *generic_ip;
 433         } u;
 434 };
 435
 436 /* Inode state bits.. */
 437 #define I_DIRTY         1
 438 #define I_LOCK          2
 439 #define I_FREEING       4
 440 #define I_CLEAR         8
 441
 442 extern void __mark_inode_dirty(struct inode *);
 443 static inline void mark_inode_dirty(struct inode *inode)
 444 {
 445         if (!(inode->i_state & I_DIRTY))
 446                 __mark_inode_dirty(inode);
 447 }
 448
 449 struct fown_struct {
 450         int pid;                /* pid or -pgrp where SIGIO should be sent */
 451         uid_t uid, euid;        /* uid/euid of process setting the owner */
 452         int signum;             /* posix.1b rt signal to be delivered on IO */
 453 };
 454
 455 struct file {
 456         struct list_head        f_list;
 457         struct dentry           *f_dentry;
 458         struct vfsmount         *f_vfsmnt;
 459         struct file_operations  *f_op;
 460         atomic_t                f_count;
 461         unsigned int            f_flags;
 462         mode_t                  f_mode;
 463         loff_t                  f_pos;
 464         unsigned long           f_reada, f_ramax, f_raend, f_ralen, f_rawin;
 465         struct fown_struct      f_owner;
 466         unsigned int            f_uid, f_gid;
 467         int                     f_error;
 468
 469         unsigned long           f_version;
 470
 471         /* needed for tty driver, and maybe others */
 472         void                    *private_data;
 473 };
 474 extern spinlock_t files_lock;
 475 #define file_list_lock() spin_lock(&files_lock);
 476 #define file_list_unlock() spin_unlock(&files_lock);
 477
 478 #define get_file(x)     atomic_inc(&(x)->f_count)
 479 #define file_count(x)   atomic_read(&(x)->f_count)
 480
 481 extern int init_private_file(struct file *, struct dentry *, int);
 482
 483 #define FL_POSIX        1
 484 #define FL_FLOCK        2
 485 #define FL_BROKEN       4       /* broken flock() emulation */
 486 #define FL_ACCESS       8       /* for processes suspended by mandatory locking */
 487 #define FL_LOCKD        16      /* lock held by rpc.lockd */
 488
 489 /*
 490  * The POSIX file lock owner is determined by
 491  * the "struct files_struct" in the thread group
 492  * (or NULL for no owner - BSD locks).
 493  *
 494  * Lockd stuffs a "host" pointer into this.
 495  */
 496 typedef struct files_struct *fl_owner_t;
 497
 498 struct file_lock {
 499         struct file_lock *fl_next;      /* singly linked list for this inode  */
 500         struct file_lock *fl_nextlink;  /* doubly linked list of all locks */
 501         struct file_lock *fl_prevlink;  /* used to simplify lock removal */
 502         struct file_lock *fl_nextblock; /* circular list of blocked processes */
 503         struct file_lock *fl_prevblock;
 504         fl_owner_t fl_owner;
 505         unsigned int fl_pid;
 506         wait_queue_head_t fl_wait;
 507         struct file *fl_file;
 508         unsigned char fl_flags;
 509         unsigned char fl_type;
 510         loff_t fl_start;
 511         loff_t fl_end;
 512
 513         void (*fl_notify)(struct file_lock *);  /* unblock callback */
 514         void (*fl_insert)(struct file_lock *);  /* lock insertion callback */
 515         void (*fl_remove)(struct file_lock *);  /* lock removal callback */
 516
 517         union {
 518                 struct nfs_lock_info    nfs_fl;
 519         } fl_u;
 520 };
 521
 522 /* The following constant reflects the upper bound of the file/locking space */
 523 #ifndef OFFSET_MAX
 524 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
 525 #define OFFSET_MAX      INT_LIMIT(loff_t)
 526 #endif
 527
 528 extern struct file_lock                 *file_lock_table;
 529
 530 #include <linux/fcntl.h>
 531
 532 extern int fcntl_getlk(unsigned int, struct flock *);
 533 extern int fcntl_setlk(unsigned int, unsigned int, struct flock *);
 534
 535 /* fs/locks.c */
 536 extern void locks_remove_posix(struct file *, fl_owner_t);
 537 extern void locks_remove_flock(struct file *);
 538 extern struct file_lock *posix_test_lock(struct file *, struct file_lock *);
 539 extern int posix_lock_file(struct file *, struct file_lock *, unsigned int);
 540 extern void posix_block_lock(struct file_lock *, struct file_lock *);
 541 extern void posix_unblock_lock(struct file_lock *);
 542
 543 struct fasync_struct {
 544         int     magic;
 545         int     fa_fd;
 546         struct  fasync_struct   *fa_next; /* singly linked list */
 547         struct  file            *fa_file;
 548 };
 549
 550 struct nameidata {
 551         struct dentry *dentry;
 552         struct vfsmount *mnt;
 553         struct qstr last;
 554 };
 555
 556 #define FASYNC_MAGIC 0x4601
 557
 558 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
 559
 560 #define DQUOT_USR_ENABLED       0x01            /* User diskquotas enabled */
 561 #define DQUOT_GRP_ENABLED       0x02            /* Group diskquotas enabled */
 562
 563 struct quota_mount_options
 564 {
 565         unsigned int flags;                     /* Flags for diskquotas on this device */
 566         struct semaphore dqio_sem;              /* lock device while I/O in progress */
 567         struct semaphore dqoff_sem;             /* serialize quota_off() and quota_on() on device */
 568         struct file *files[MAXQUOTAS];          /* fp's to quotafiles */
 569         time_t inode_expire[MAXQUOTAS];         /* expiretime for inode-quota */
 570         time_t block_expire[MAXQUOTAS];         /* expiretime for block-quota */
 571         char rsquash[MAXQUOTAS];                /* for quotas threat root as any other user */
 572 };
 573
 574 /*
 575  *      Umount options
 576  */
 577
 578 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
 579
 580 #include <linux/minix_fs_sb.h>
 581 #include <linux/ext2_fs_sb.h>
 582 #include <linux/hpfs_fs_sb.h>
 583 #include <linux/ntfs_fs_sb.h>
 584 #include <linux/msdos_fs_sb.h>
 585 #include <linux/iso_fs_sb.h>
 586 #include <linux/nfs_fs_sb.h>
 587 #include <linux/sysv_fs_sb.h>
 588 #include <linux/affs_fs_sb.h>
 589 #include <linux/ufs_fs_sb.h>
 590 #include <linux/efs_fs_sb.h>
 591 #include <linux/romfs_fs_sb.h>
 592 #include <linux/smb_fs_sb.h>
 593 #include <linux/hfs_fs_sb.h>
 594 #include <linux/adfs_fs_sb.h>
 595 #include <linux/qnx4_fs_sb.h>
 596 #include <linux/bfs_fs_sb.h>
 597 #include <linux/udf_fs_sb.h>
 598 #include <linux/ncp_fs_sb.h>
 599 #include <linux/usbdev_fs_sb.h>
 600
 601 extern struct list_head super_blocks;
 602
 603 #define sb_entry(list)  list_entry((list), struct super_block, s_list)
 604 struct super_block {
 605         struct list_head        s_list;         /* Keep this first */
 606         kdev_t                  s_dev;
 607         unsigned long           s_blocksize;
 608         unsigned char           s_blocksize_bits;
 609         unsigned char           s_lock;
 610         unsigned char           s_dirt;
 611         struct file_system_type *s_type;
 612         struct super_operations *s_op;
 613         struct dquot_operations *dq_op;
 614         unsigned long           s_flags;
 615         unsigned long           s_magic;
 616         struct dentry           *s_root;
 617         wait_queue_head_t       s_wait;
 618
 619         struct list_head        s_dirty;        /* dirty inodes */
 620         struct list_head        s_files;
 621
 622         struct block_device     *s_bdev;
 623         struct quota_mount_options s_dquot;     /* Diskquota specific options */
 624
 625         union {
 626                 struct minix_sb_info    minix_sb;
 627                 struct ext2_sb_info     ext2_sb;
 628                 struct hpfs_sb_info     hpfs_sb;
 629                 struct ntfs_sb_info     ntfs_sb;
 630                 struct msdos_sb_info    msdos_sb;
 631                 struct isofs_sb_info    isofs_sb;
 632                 struct nfs_sb_info      nfs_sb;
 633                 struct sysv_sb_info     sysv_sb;
 634                 struct affs_sb_info     affs_sb;
 635                 struct ufs_sb_info      ufs_sb;
 636                 struct efs_sb_info      efs_sb;
 637                 struct romfs_sb_info    romfs_sb;
 638                 struct smb_sb_info      smbfs_sb;
 639                 struct hfs_sb_info      hfs_sb;
 640                 struct adfs_sb_info     adfs_sb;
 641                 struct qnx4_sb_info     qnx4_sb;
 642                 struct bfs_sb_info      bfs_sb;
 643                 struct udf_sb_info      udf_sb;
 644                 struct ncp_sb_info      ncpfs_sb;
 645                 struct usbdev_sb_info   usbdevfs_sb;
 646                 void                    *generic_sbp;
 647         } u;
 648         /*
 649          * The next field is for VFS *only*. No filesystems have any business
 650          * even looking at it. You had been warned.
 651          */
 652         struct semaphore s_vfs_rename_sem;      /* Kludge */
 653
 654         /* The next field is used by knfsd when converting a (inode number based)
 655          * file handle into a dentry. As it builds a path in the dcache tree from
 656          * the bottom up, there may for a time be a subpath of dentrys which is not
 657          * connected to the main tree.  This semaphore ensure that there is only ever
 658          * one such free path per filesystem.  Note that unconnected files (or other
 659          * non-directories) are allowed, but not unconnected diretories.
 660          */
 661         struct semaphore s_nfsd_free_path_sem;
 662 };
 663
 664 /*
 665  * VFS helper functions..
 666  */
 667 extern int vfs_create(struct inode *, struct dentry *, int);
 668 extern int vfs_mkdir(struct inode *, struct dentry *, int);
 669 extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
 670 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
 671 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 672 extern int vfs_rmdir(struct inode *, struct dentry *);
 673 extern int vfs_unlink(struct inode *, struct dentry *);
 674 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 675
 676 /*
 677  * This is the "filldir" function type, used by readdir() to let
 678  * the kernel specify what kind of dirent layout it wants to have.
 679  * This allows the kernel to read directories into kernel space or
 680  * to have different dirent layouts depending on the binary type.
 681  */
 682 typedef int (*filldir_t)(void *, const char *, int, off_t, ino_t);
 683
 684 struct block_device_operations {
 685         int (*open) (struct inode *, struct file *);
 686         int (*release) (struct inode *, struct file *);
 687         int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
 688         int (*check_media_change) (kdev_t);
 689         int (*revalidate) (kdev_t);
 690 };
 691
 692 struct file_operations {
 693         loff_t (*llseek) (struct file *, loff_t, int);
 694         ssize_t (*read) (struct file *, char *, size_t, loff_t *);
 695         ssize_t (*write) (struct file *, const char *, size_t, loff_t *);
 696         int (*readdir) (struct file *, void *, filldir_t);
 697         unsigned int (*poll) (struct file *, struct poll_table_struct *);
 698         int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
 699         int (*mmap) (struct file *, struct vm_area_struct *);
 700         int (*open) (struct inode *, struct file *);
 701         int (*flush) (struct file *);
 702         int (*release) (struct inode *, struct file *);
 703         int (*fsync) (struct file *, struct dentry *);
 704         int (*fasync) (int, struct file *, int);
 705         int (*lock) (struct file *, int, struct file_lock *);
 706         ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *);
 707         ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *);
 708 };
 709
 710 struct inode_operations {
 711         int (*create) (struct inode *,struct dentry *,int);
 712         struct dentry * (*lookup) (struct inode *,struct dentry *);
 713         int (*link) (struct dentry *,struct inode *,struct dentry *);
 714         int (*unlink) (struct inode *,struct dentry *);
 715         int (*symlink) (struct inode *,struct dentry *,const char *);
 716         int (*mkdir) (struct inode *,struct dentry *,int);
 717         int (*rmdir) (struct inode *,struct dentry *);
 718         int (*mknod) (struct inode *,struct dentry *,int,int);
 719         int (*rename) (struct inode *, struct dentry *,
 720                         struct inode *, struct dentry *);
 721         int (*readlink) (struct dentry *, char *,int);
 722         int (*follow_link) (struct dentry *, struct nameidata *);
 723         void (*truncate) (struct inode *);
 724         int (*permission) (struct inode *, int);
 725         int (*revalidate) (struct dentry *);
 726         int (*setattr) (struct dentry *, struct iattr *);
 727         int (*getattr) (struct dentry *, struct iattr *);
 728 };
 729
 730 /*
 731  * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
 732  * without the big kernel lock held in all filesystems.
 733  */
 734 struct super_operations {
 735         void (*read_inode) (struct inode *);
 736         void (*write_inode) (struct inode *);
 737         void (*put_inode) (struct inode *);
 738         void (*delete_inode) (struct inode *);
 739         void (*put_super) (struct super_block *);
 740         void (*write_super) (struct super_block *);
 741         int (*statfs) (struct super_block *, struct statfs *);
 742         int (*remount_fs) (struct super_block *, int *, char *);
 743         void (*clear_inode) (struct inode *);
 744         void (*umount_begin) (struct super_block *);
 745 };
 746
 747 struct dquot_operations {
 748         void (*initialize) (struct inode *, short);
 749         void (*drop) (struct inode *);
 750         int (*alloc_block) (const struct inode *, unsigned long, char);
 751         int (*alloc_inode) (const struct inode *, unsigned long);
 752         void (*free_block) (const struct inode *, unsigned long);
 753         void (*free_inode) (const struct inode *, unsigned long);
 754         int (*transfer) (struct dentry *, struct iattr *);
 755 };
 756
 757 struct file_system_type {
 758         const char *name;
 759         int fs_flags;
 760         struct super_block *(*read_super) (struct super_block *, void *, int);
 761         struct module *owner;
 762         struct file_system_type * next;
 763 };
 764
 765 #define DECLARE_FSTYPE(var,type,read,flags) \
 766 struct file_system_type var = { \
 767         name:           type, \
 768         read_super:     read, \
 769         fs_flags:       flags, \
 770         owner:          THIS_MODULE, \
 771 }
 772
 773 #define DECLARE_FSTYPE_DEV(var,type,read) \
 774         DECLARE_FSTYPE(var,type,read,FS_REQUIRES_DEV)
 775
 776 extern int register_filesystem(struct file_system_type *);
 777 extern int unregister_filesystem(struct file_system_type *);
 778
 779 static inline int vfs_statfs(struct super_block *sb, struct statfs *buf)
 780 {
 781         if (!sb)
 782                 return -ENODEV;
 783         if (!sb->s_op || !sb->s_op->statfs)
 784                 return -ENOSYS;
 785         memset(buf, 0, sizeof(struct statfs));
 786         return sb->s_op->statfs(sb, buf);
 787 }
 788
 789 /* Return value for VFS lock functions - tells locks.c to lock conventionally
 790  * REALLY kosha for root NFS and nfs_lock
 791  */
 792 #define LOCK_USE_CLNT 1
 793
 794 #define FLOCK_VERIFY_READ  1
 795 #define FLOCK_VERIFY_WRITE 2
 796
 797 extern int locks_mandatory_locked(struct inode *);
 798 extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
 799
 800 /*
 801  * Candidates for mandatory locking have the setgid bit set
 802  * but no group execute bit -  an otherwise meaningless combination.
 803  */
 804 #define MANDATORY_LOCK(inode) \
 805         (IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 806
 807 static inline int locks_verify_locked(struct inode *inode)
 808 {
 809         if (MANDATORY_LOCK(inode))
 810                 return locks_mandatory_locked(inode);
 811         return 0;
 812 }
 813
 814 extern inline int locks_verify_area(int read_write, struct inode *inode,
 815                                     struct file *filp, loff_t offset,
 816                                     size_t count)
 817 {
 818         if (inode->i_flock && MANDATORY_LOCK(inode))
 819                 return locks_mandatory_area(read_write, inode, filp, offset, count);
 820         return 0;
 821 }
 822
 823 extern inline int locks_verify_truncate(struct inode *inode,
 824                                     struct file *filp,
 825                                     loff_t size)
 826 {
 827         if (inode->i_flock && MANDATORY_LOCK(inode))
 828                 return locks_mandatory_area(
 829                         FLOCK_VERIFY_WRITE, inode, filp,
 830                         size < inode->i_size ? size : inode->i_size,
 831                         abs(inode->i_size - size)
 832                 );
 833         return 0;
 834 }
 835
 836
 837 /* fs/open.c */
 838
 839 asmlinkage long sys_open(const char *, int, int);
 840 asmlinkage long sys_close(unsigned int);        /* yes, it's really unsigned */
 841 extern int do_close(unsigned int, int);         /* yes, it's really unsigned */
 842 extern int do_truncate(struct dentry *, loff_t start);
 843 extern int get_unused_fd(void);
 844 extern void put_unused_fd(unsigned int);
 845
 846 extern struct file *filp_open(const char *, int, int);
 847 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
 848 extern int filp_close(struct file *, fl_owner_t id);
 849 extern char * getname(const char *);
 850 #define __getname()     ((char *) __get_free_page(GFP_KERNEL))
 851 #define putname(name)   free_page((unsigned long)(name))
 852
 853 enum {BDEV_FILE, BDEV_SWAP, BDEV_FS, BDEV_RAW};
 854 extern void kill_fasync(struct fasync_struct *, int, int);
 855 extern int register_blkdev(unsigned int, const char *, struct block_device_operations *);
 856 extern int unregister_blkdev(unsigned int, const char *);
 857 extern struct block_device *bdget(dev_t);
 858 extern void bdput(struct block_device *);
 859 extern int blkdev_open(struct inode *, struct file *);
 860 extern struct file_operations def_blk_fops;
 861 extern struct file_operations def_fifo_fops;
 862 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
 863 extern int blkdev_get(struct block_device *, mode_t, unsigned, int);
 864 extern int blkdev_put(struct block_device *, int);
 865
 866 /* fs/devices.c */
 867 extern const struct block_device_operations *get_blkfops(unsigned int);
 868 extern struct file_operations *get_chrfops(unsigned int, unsigned int);
 869 extern int register_chrdev(unsigned int, const char *, struct file_operations *);
 870 extern int unregister_chrdev(unsigned int, const char *);
 871 extern int chrdev_open(struct inode *, struct file *);
 872 extern const char * bdevname(kdev_t);
 873 extern const char * cdevname(kdev_t);
 874 extern const char * kdevname(kdev_t);
 875 extern void init_special_inode(struct inode *, umode_t, int);
 876
 877 /* Invalid inode operations -- fs/bad_inode.c */
 878 extern void make_bad_inode(struct inode *);
 879 extern int is_bad_inode(struct inode *);
 880
 881 extern struct file_operations connecting_fifo_fops;
 882 extern struct file_operations read_fifo_fops;
 883 extern struct file_operations write_fifo_fops;
 884 extern struct file_operations rdwr_fifo_fops;
 885 extern struct file_operations read_pipe_fops;
 886 extern struct file_operations write_pipe_fops;
 887 extern struct file_operations rdwr_pipe_fops;
 888
 889 extern int fs_may_remount_ro(struct super_block *);
 890 extern int fs_may_mount(kdev_t);
 891
 892 extern int try_to_free_buffers(struct page *);
 893 extern void refile_buffer(struct buffer_head * buf);
 894
 895 #define BUF_CLEAN       0
 896 #define BUF_LOCKED      1       /* Buffers scheduled for write */
 897 #define BUF_DIRTY       2       /* Dirty buffers, not yet scheduled for write */
 898 #define BUF_PROTECTED   3       /* Ramdisk persistent storage */
 899 #define NR_LIST         4
 900
 901 /*
 902  * This is called by bh->b_end_io() handlers when I/O has completed.
 903  */
 904 extern inline void mark_buffer_uptodate(struct buffer_head * bh, int on)
 905 {
 906         if (on)
 907                 set_bit(BH_Uptodate, &bh->b_state);
 908         else
 909                 clear_bit(BH_Uptodate, &bh->b_state);
 910 }
 911
 912 #define atomic_set_buffer_clean(bh) test_and_clear_bit(BH_Dirty, &(bh)->b_state)
 913
 914 extern inline void __mark_buffer_clean(struct buffer_head *bh)
 915 {
 916         refile_buffer(bh);
 917 }
 918
 919 extern inline void mark_buffer_clean(struct buffer_head * bh)
 920 {
 921         if (atomic_set_buffer_clean(bh))
 922                 __mark_buffer_clean(bh);
 923 }
 924
 925 #define atomic_set_buffer_protected(bh) test_and_set_bit(BH_Protected, &(bh)->b_state)
 926
 927 extern inline void __mark_buffer_protected(struct buffer_head *bh)
 928 {
 929         refile_buffer(bh);
 930 }
 931
 932 extern inline void mark_buffer_protected(struct buffer_head * bh)
 933 {
 934         if (!atomic_set_buffer_protected(bh))
 935                 __mark_buffer_protected(bh);
 936 }
 937
 938 extern void FASTCALL(__mark_buffer_dirty(struct buffer_head *bh, int flag));
 939 extern void FASTCALL(mark_buffer_dirty(struct buffer_head *bh, int flag));
 940
 941 #define atomic_set_buffer_dirty(bh) test_and_set_bit(BH_Dirty, &(bh)->b_state)
 942
 943 extern void balance_dirty(kdev_t);
 944 extern int check_disk_change(kdev_t);
 945 extern int invalidate_inodes(struct super_block *);
 946 extern void invalidate_inode_pages(struct inode *);
 947 #define invalidate_buffers(dev) __invalidate_buffers((dev), 0)
 948 #define destroy_buffers(dev)    __invalidate_buffers((dev), 1)
 949 extern void __invalidate_buffers(kdev_t dev, int);
 950 extern int floppy_is_wp(int);
 951 extern void sync_inodes(kdev_t);
 952 extern void write_inode_now(struct inode *);
 953 extern void sync_dev(kdev_t);
 954 extern int fsync_dev(kdev_t);
 955 extern void sync_supers(kdev_t);
 956 extern int bmap(struct inode *, int);
 957 extern int notify_change(struct dentry *, struct iattr *);
 958 extern int permission(struct inode *, int);
 959 extern int get_write_access(struct inode *);
 960 extern void put_write_access(struct inode *);
 961 extern struct dentry * do_mknod(const char *, int, dev_t);
 962 extern int do_pipe(int *);
 963
 964 extern int open_namei(const char *, int, int, struct nameidata *);
 965
 966 extern int kernel_read(struct file *, unsigned long, char *, unsigned long);
 967 extern struct file * open_exec(const char *);
 968
 969 /* fs/dcache.c -- generic fs support functions */
 970 extern int is_subdir(struct dentry *, struct dentry *);
 971 extern ino_t find_inode_number(struct dentry *, struct qstr *);
 972
 973 /*
 974  * Kernel pointers have redundant information, so we can use a
 975  * scheme where we can return either an error code or a dentry
 976  * pointer with the same return value.
 977  *
 978  * This should be a per-architecture thing, to allow different
 979  * error and pointer decisions.
 980  */
 981 #define ERR_PTR(err)    ((void *)((long)(err)))
 982 #define PTR_ERR(ptr)    ((long)(ptr))
 983 #define IS_ERR(ptr)     ((unsigned long)(ptr) > (unsigned long)(-1000))
 984
 985 /*
 986  * The bitmask for a lookup event:
 987  *  - follow links at the end
 988  *  - require a directory
 989  *  - ending slashes ok even for nonexistent files
 990  *  - internal "there are more path compnents" flag
 991  */
 992 #define LOOKUP_FOLLOW           (1)
 993 #define LOOKUP_DIRECTORY        (2)
 994 #define LOOKUP_SLASHOK          (4)
 995 #define LOOKUP_CONTINUE         (8)
 996 #define LOOKUP_POSITIVE         (16)
 997 #define LOOKUP_PARENT           (32)
 998
 999 /*
1000  * "descriptor" for what we're up to with a read for sendfile().
1001  * This allows us to use the same read code yet
1002  * have multiple different users of the data that
1003  * we read from a file.
1004  *
1005  * The simplest case just copies the data to user
1006  * mode.
1007  */
1008 typedef struct {
1009         size_t written;
1010         size_t count;
1011         char * buf;
1012         int error;
1013 } read_descriptor_t;
1014
1015 typedef int (*read_actor_t)(read_descriptor_t *, struct page *, unsigned long, unsigned long);
1016
1017 extern struct dentry * lookup_dentry(const char *, unsigned int);
1018 extern int walk_init(const char *, unsigned, struct nameidata *);
1019 extern int walk_name(const char *, unsigned, struct nameidata *);
1020 extern struct dentry * lookup_one(const char *, struct dentry *);
1021 extern struct dentry * __namei(const char *, unsigned int);
1022
1023 #define namei(pathname)         __namei(pathname, LOOKUP_FOLLOW)
1024 #define lnamei(pathname)        __namei(pathname, 0)
1025
1026 extern void iput(struct inode *);
1027 extern struct inode * igrab(struct inode *);
1028 extern ino_t iunique(struct super_block *, ino_t);
1029
1030 typedef int (*find_inode_t)(struct inode *, unsigned long, void *);
1031 extern struct inode * iget4(struct super_block *, unsigned long, find_inode_t, void *);
1032 static inline struct inode *iget(struct super_block *sb, unsigned long ino)
1033 {
1034         return iget4(sb, ino, NULL, NULL);
1035 }
1036
1037 extern void clear_inode(struct inode *);
1038 extern struct inode * get_empty_inode(void);
1039
1040 extern void insert_inode_hash(struct inode *);
1041 extern void remove_inode_hash(struct inode *);
1042 extern struct file * get_empty_filp(void);
1043 extern void file_move(struct file *f, struct list_head *list);
1044 extern void file_moveto(struct file *new, struct file *old);
1045 extern struct buffer_head * get_hash_table(kdev_t, int, int);
1046 extern struct buffer_head * getblk(kdev_t, int, int);
1047 extern void ll_rw_block(int, int, struct buffer_head * bh[]);
1048 extern int is_read_only(kdev_t);
1049 extern void __brelse(struct buffer_head *);
1050 extern inline void brelse(struct buffer_head *buf)
1051 {
1052         if (buf)
1053                 __brelse(buf);
1054 }
1055 extern void __bforget(struct buffer_head *);
1056 extern inline void bforget(struct buffer_head *buf)
1057 {
1058         if (buf)
1059                 __bforget(buf);
1060 }
1061 extern void set_blocksize(kdev_t, int);
1062 extern unsigned int get_hardblocksize(kdev_t);
1063 extern struct buffer_head * bread(kdev_t, int, int);
1064 extern struct buffer_head * breada(kdev_t, int, int, unsigned int, unsigned int);
1065 extern void wakeup_bdflush(int wait);
1066
1067 extern int brw_page(int, struct page *, kdev_t, int [], int);
1068
1069 typedef int (*writepage_t)(struct file *, struct page *, unsigned long, unsigned long, const char *);
1070 typedef int (get_block_t)(struct inode*,long,struct buffer_head*,int);
1071
1072 /* Generic buffer handling for block filesystems.. */
1073 extern int block_flushpage(struct page *, unsigned long);
1074 extern int block_symlink(struct inode *, const char *, int);
1075 extern int block_write_full_page(struct page*, get_block_t*);
1076 extern int block_read_full_page(struct page*, get_block_t*);
1077 extern int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
1078 extern int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*,
1079                                 unsigned long *);
1080 int generic_block_bmap(struct address_space *, long, get_block_t *);
1081 int generic_commit_write(struct file *, struct page *, unsigned, unsigned);
1082
1083 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
1084 extern ssize_t generic_file_read(struct file *, char *, size_t, loff_t *);
1085 extern ssize_t generic_file_write(struct file *, const char *, size_t, loff_t *);
1086 extern void do_generic_file_read(struct file *, loff_t *, read_descriptor_t *, read_actor_t);
1087
1088 extern ssize_t generic_read_dir(struct file *, char *, size_t, loff_t *);
1089
1090 extern struct file_operations generic_ro_fops;
1091
1092 extern int vfs_readlink(struct dentry *, char *, int, const char *);
1093 extern int vfs_follow_link(struct nameidata *, const char *);
1094 extern int page_readlink(struct dentry *, char *, int);
1095 extern int page_follow_link(struct dentry *, struct nameidata *);
1096 extern struct inode_operations page_symlink_inode_operations;
1097
1098 extern int vfs_readdir(struct file *, filldir_t, void *);
1099
1100 extern struct super_block *get_super(kdev_t);
1101 struct super_block *get_empty_super(void);
1102 void remove_vfsmnt(kdev_t dev);
1103 extern void put_super(kdev_t);
1104 unsigned long generate_cluster(kdev_t, int b[], int);
1105 unsigned long generate_cluster_swab32(kdev_t, int b[], int);
1106 extern kdev_t ROOT_DEV;
1107 extern char root_device_name[];
1108
1109
1110 extern void show_buffers(void);
1111 extern void mount_root(void);
1112
1113 #ifdef CONFIG_BLK_DEV_INITRD
1114 extern kdev_t real_root_dev;
1115 extern int change_root(kdev_t, const char *);
1116 #endif
1117
1118 extern ssize_t char_read(struct file *, char *, size_t, loff_t *);
1119 extern ssize_t block_read(struct file *, char *, size_t, loff_t *);
1120 extern int read_ahead[];
1121
1122 extern ssize_t char_write(struct file *, const char *, size_t, loff_t *);
1123 extern ssize_t block_write(struct file *, const char *, size_t, loff_t *);
1124
1125 extern int file_fsync(struct file *, struct dentry *);
1126 extern int generic_buffer_fdatasync(struct inode *inode, unsigned long start_idx, unsigned long end_idx);
1127
1128 extern int inode_change_ok(struct inode *, struct iattr *);
1129 extern void inode_setattr(struct inode *, struct iattr *);
1130
1131 /*
1132  * Common dentry functions for inclusion in the VFS
1133  * or in other stackable file systems.  Some of these
1134  * functions were in linux/fs/ C (VFS) files.
1135  *
1136  */
1137
1138 /*
1139  * We need to do a check-parent every time
1140  * after we have locked the parent - to verify
1141  * that the parent is still our parent and
1142  * that we are still hashed onto it..
1143  *
1144  * This is required in case two processes race
1145  * on removing (or moving) the same entry: the
1146  * parent lock will serialize them, but the
1147  * other process will be too late..
1148  */
1149 #define check_parent(dir, dentry) \
1150         ((dir) == (dentry)->d_parent && !d_unhashed(dentry))
1151
1152 /*
1153  * Locking the parent is needed to:
1154  *  - serialize directory operations
1155  *  - make sure the parent doesn't change from
1156  *    under us in the middle of an operation.
1157  *
1158  * NOTE! Right now we'd rather use a "struct inode"
1159  * for this, but as I expect things to move toward
1160  * using dentries instead for most things it is
1161  * probably better to start with the conceptually
1162  * better interface of relying on a path of dentries.
1163  */
1164 static inline struct dentry *lock_parent(struct dentry *dentry)
1165 {
1166         struct dentry *dir = dget(dentry->d_parent);
1167
1168         down(&dir->d_inode->i_sem);
1169         return dir;
1170 }
1171
1172 static inline struct dentry *get_parent(struct dentry *dentry)
1173 {
1174         return dget(dentry->d_parent);
1175 }
1176
1177 static inline void unlock_dir(struct dentry *dir)
1178 {
1179         up(&dir->d_inode->i_sem);
1180         dput(dir);
1181 }
1182
1183 /*
1184  * Whee.. Deadlock country. Happily there are only two VFS
1185  * operations that does this..
1186  */
1187 static inline void double_down(struct semaphore *s1, struct semaphore *s2)
1188 {
1189         if (s1 != s2) {
1190                 if ((unsigned long) s1 < (unsigned long) s2) {
1191                         struct semaphore *tmp = s2;
1192                         s2 = s1; s1 = tmp;
1193                 }
1194                 down(s1);
1195         }
1196         down(s2);
1197 }
1198
1199 /*
1200  * Ewwwwwwww... _triple_ lock. We are guaranteed that the 3rd argument is
1201  * not equal to 1st and not equal to 2nd - the first case (target is parent of
1202  * source) would be already caught, the second is plain impossible (target is
1203  * its own parent and that case would be caught even earlier). Very messy.
1204  * I _think_ that it works, but no warranties - please, look it through.
1205  * Pox on bloody lusers who mandated overwriting rename() for directories...
1206  */
1207
1208 static inline void triple_down(struct semaphore *s1,
1209                                struct semaphore *s2,
1210                                struct semaphore *s3)
1211 {
1212         if (s1 != s2) {
1213                 if ((unsigned long) s1 < (unsigned long) s2) {
1214                         if ((unsigned long) s1 < (unsigned long) s3) {
1215                                 struct semaphore *tmp = s3;
1216                                 s3 = s1; s1 = tmp;
1217                         }
1218                         if ((unsigned long) s1 < (unsigned long) s2) {
1219                                 struct semaphore *tmp = s2;
1220                                 s2 = s1; s1 = tmp;
1221                         }
1222                 } else {
1223                         if ((unsigned long) s1 < (unsigned long) s3) {
1224                                 struct semaphore *tmp = s3;
1225                                 s3 = s1; s1 = tmp;
1226                         }
1227                         if ((unsigned long) s2 < (unsigned long) s3) {
1228                                 struct semaphore *tmp = s3;
1229                                 s3 = s2; s2 = tmp;
1230                         }
1231                 }
1232                 down(s1);
1233         } else if ((unsigned long) s2 < (unsigned long) s3) {
1234                 struct semaphore *tmp = s3;
1235                 s3 = s2; s2 = tmp;
1236         }
1237         down(s2);
1238         down(s3);
1239 }
1240
1241 static inline void double_up(struct semaphore *s1, struct semaphore *s2)
1242 {
1243         up(s1);
1244         if (s1 != s2)
1245                 up(s2);
1246 }
1247
1248 static inline void triple_up(struct semaphore *s1,
1249                              struct semaphore *s2,
1250                              struct semaphore *s3)
1251 {
1252         up(s1);
1253         if (s1 != s2)
1254                 up(s2);
1255         up(s3);
1256 }
1257
1258 static inline void double_lock(struct dentry *d1, struct dentry *d2)
1259 {
1260         double_down(&d1->d_inode->i_sem, &d2->d_inode->i_sem);
1261 }
1262
1263 static inline void double_unlock(struct dentry *d1, struct dentry *d2)
1264 {
1265         double_up(&d1->d_inode->i_sem,&d2->d_inode->i_sem);
1266         dput(d1);
1267         dput(d2);
1268 }
1269
1270 #endif /* __KERNEL__ */
1271
1272 #endif /* _LINUX_FS_H */