LXR linux/fs/autofs/autofs

   1/* -*- linux-c -*- ------------------------------------------------------- *
   2 *   
   3 * linux/fs/autofs/autofs_i.h
   4 *
   5 *   Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
   6 *
   7 * This file is part of the Linux kernel and is made available under
   8 * the terms of the GNU General Public License, version 2, or at your
   9 * option, any later version, incorporated herein by reference.
  10 *
  11 * ----------------------------------------------------------------------- */
  12
  13/* Internal header file for autofs */
  14
  15#include <linux/auto_fs.h>
  16
  17/* This is the range of ioctl() numbers we claim as ours */
  18#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  19#define AUTOFS_IOC_COUNT     32
  20
  21#include <linux/kernel.h>
  22#include <linux/slab.h>
  23#include <linux/time.h>
  24#include <linux/string.h>
  25#include <linux/wait.h>
  26#include <linux/dcache.h>
  27#include <linux/namei.h>
  28#include <linux/mount.h>
  29#include <linux/sched.h>
  30
  31#include <asm/current.h>
  32#include <asm/uaccess.h>
  33
  34#ifdef DEBUG
  35#define DPRINTK(D) (printk D)
  36#else
  37#define DPRINTK(D) ((void)0)
  38#endif
  39
  40/*
  41 * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  42 * kernel will keep the negative response cached for up to the time given
  43 * here, although the time can be shorter if the kernel throws the dcache
  44 * entry away.  This probably should be settable from user space.
  45 */
  46#define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  47
  48/* Structures associated with the root directory hash table */
  49
  50#define AUTOFS_HASH_SIZE 67
  51
  52struct autofs_dir_ent {
  53        int hash;
  54        char *name;
  55        int len;
  56        ino_t ino;
  57        struct dentry *dentry;
  58        /* Linked list of entries */
  59        struct autofs_dir_ent *next;
  60        struct autofs_dir_ent **back;
  61        /* The following entries are for the expiry system */
  62        unsigned long last_usage;
  63        struct list_head exp;
  64};
  65
  66struct autofs_dirhash {
  67        struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
  68        struct list_head expiry_head;
  69};
  70
  71struct autofs_wait_queue {
  72        wait_queue_head_t queue;
  73        struct autofs_wait_queue *next;
  74        autofs_wqt_t wait_queue_token;
  75        /* We use the following to see what we are waiting for */
  76        int hash;
  77        int len;
  78        char *name;
  79        /* This is for status reporting upon return */
  80        int status;
  81        int wait_ctr;
  82};
  83
  84struct autofs_symlink {
  85        char *data;
  86        int len;
  87        time_t mtime;
  88};
  89
  90#define AUTOFS_MAX_SYMLINKS 256
  91
  92#define AUTOFS_ROOT_INO      1
  93#define AUTOFS_FIRST_SYMLINK 2
  94#define AUTOFS_FIRST_DIR_INO (AUTOFS_FIRST_SYMLINK+AUTOFS_MAX_SYMLINKS)
  95
  96#define AUTOFS_SYMLINK_BITMAP_LEN \
  97        ((AUTOFS_MAX_SYMLINKS+((sizeof(long)*1)-1))/(sizeof(long)*8))
  98
  99#define AUTOFS_SBI_MAGIC 0x6d4a556d
 100
 101struct autofs_sb_info {
 102        u32 magic;
 103        struct file *pipe;
 104        struct pid *oz_pgrp;
 105        int catatonic;
 106        struct super_block *sb;
 107        unsigned long exp_timeout;
 108        ino_t next_dir_ino;
 109        struct autofs_wait_queue *queues; /* Wait queue pointer */
 110        struct autofs_dirhash dirhash; /* Root directory hash */
 111        struct autofs_symlink symlink[AUTOFS_MAX_SYMLINKS];
 112        unsigned long symlink_bitmap[AUTOFS_SYMLINK_BITMAP_LEN];
 113};
 114
 115static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 116{
 117        return (struct autofs_sb_info *)(sb->s_fs_info);
 118}
 119
 120/* autofs_oz_mode(): do we see the man behind the curtain?  (The
 121   processes which do manipulations for us in user space sees the raw
 122   filesystem without "magic".) */
 123
 124static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
 125        return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 126}
 127
 128/* Hash operations */
 129
 130void autofs_initialize_hash(struct autofs_dirhash *);
 131struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
 132void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
 133void autofs_hash_delete(struct autofs_dir_ent *);
 134struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
 135void autofs_hash_dputall(struct autofs_dirhash *);
 136void autofs_hash_nuke(struct autofs_sb_info *);
 137
 138/* Expiration-handling functions */
 139
 140void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
 141struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *, struct vfsmount *mnt);
 142
 143/* Operations structures */
 144
 145extern const struct inode_operations autofs_root_inode_operations;
 146extern const struct inode_operations autofs_symlink_inode_operations;
 147extern const struct file_operations autofs_root_operations;
 148
 149/* Initializing function */
 150
 151int autofs_fill_super(struct super_block *, void *, int);
 152void autofs_kill_sb(struct super_block *sb);
 153struct inode *autofs_iget(struct super_block *, unsigned long);
 154
 155/* Queue management functions */
 156
 157int autofs_wait(struct autofs_sb_info *,struct qstr *);
 158int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 159void autofs_catatonic_mode(struct autofs_sb_info *);
 160
 161#ifdef DEBUG
 162void autofs_say(const char *name, int len);
 163#else
 164#define autofs_say(n,l) ((void)0)
 165#endif
 166