fs/autofs/autofs_i.h

   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/malloc.h>
  23 #include <linux/sched.h>
  24 #include <linux/string.h>
  25 #include <linux/wait.h>
  26 #include <asm/uaccess.h>
  27
  28 #ifdef DEBUG
  29 #define DPRINTK(D) (printk D)
  30 #else
  31 #define DPRINTK(D) ((void)0)
  32 #endif
  33
  34 #define AUTOFS_SUPER_MAGIC 0x0187
  35
  36 /*
  37  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  38  * kernel will keep the negative response cached for up to the time given
  39  * here, although the time can be shorter if the kernel throws the dcache
  40  * entry away.  This probably should be settable from user space.
  41  */
  42 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  43
  44 /* Structures associated with the root directory hash table */
  45
  46 #define AUTOFS_HASH_SIZE 67
  47
  48 struct autofs_dir_ent {
  49         int hash;
  50         char *name;
  51         int len;
  52         ino_t ino;
  53         struct dentry *dentry;
  54         /* Linked list of entries */
  55         struct autofs_dir_ent *next;
  56         struct autofs_dir_ent **back;
  57         /* The following entries are for the expiry system */
  58         unsigned long last_usage;
  59         struct autofs_dir_ent *exp_next;
  60         struct autofs_dir_ent *exp_prev;
  61 };
  62
  63 struct autofs_dirhash {
  64         struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
  65         struct autofs_dir_ent expiry_head;
  66 };
  67
  68 struct autofs_wait_queue {
  69         struct wait_queue *queue;
  70         struct autofs_wait_queue *next;
  71         autofs_wqt_t wait_queue_token;
  72         /* We use the following to see what we are waiting for */
  73         int hash;
  74         int len;
  75         char *name;
  76         /* This is for status reporting upon return */
  77         int status;
  78         int wait_ctr;
  79 };
  80
  81 struct autofs_symlink {
  82         char *data;
  83         int len;
  84         time_t mtime;
  85 };
  86
  87 #define AUTOFS_MAX_SYMLINKS 256
  88
  89 #define AUTOFS_ROOT_INO      1
  90 #define AUTOFS_FIRST_SYMLINK 2
  91 #define AUTOFS_FIRST_DIR_INO (AUTOFS_FIRST_SYMLINK+AUTOFS_MAX_SYMLINKS)
  92
  93 #define AUTOFS_SYMLINK_BITMAP_LEN ((AUTOFS_MAX_SYMLINKS+31)/32)
  94
  95 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  96
  97 struct autofs_sb_info {
  98         u32 magic;
  99         struct file *pipe;
 100         pid_t oz_pgrp;
 101         int catatonic;
 102         unsigned long exp_timeout;
 103         ino_t next_dir_ino;
 104         struct autofs_wait_queue *queues; /* Wait queue pointer */
 105         struct autofs_dirhash dirhash; /* Root directory hash */
 106         struct autofs_symlink symlink[AUTOFS_MAX_SYMLINKS];
 107         u32 symlink_bitmap[AUTOFS_SYMLINK_BITMAP_LEN];
 108 };
 109
 110 extern inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 111 {
 112         return (struct autofs_sb_info *)(sb->u.generic_sbp);
 113 }
 114
 115 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
 116    processes which do manipulations for us in user space sees the raw
 117    filesystem without "magic".) */
 118
 119 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
 120         return sbi->catatonic || current->pgrp == sbi->oz_pgrp;
 121 }
 122
 123 /* Hash operations */
 124
 125 void autofs_initialize_hash(struct autofs_dirhash *);
 126 struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
 127 void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
 128 void autofs_hash_delete(struct autofs_dir_ent *);
 129 struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
 130 void autofs_hash_dputall(struct autofs_dirhash *);
 131 void autofs_hash_nuke(struct autofs_dirhash *);
 132
 133 /* Expiration-handling functions */
 134
 135 void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
 136 struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *);
 137
 138 /* Operations structures */
 139
 140 extern struct inode_operations autofs_root_inode_operations;
 141 extern struct inode_operations autofs_symlink_inode_operations;
 142 extern struct inode_operations autofs_dir_inode_operations;
 143
 144 /* Initializing function */
 145
 146 struct super_block *autofs_read_super(struct super_block *, void *,int);
 147
 148 /* Queue management functions */
 149
 150 int autofs_wait(struct autofs_sb_info *,struct qstr *);
 151 int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 152 void autofs_catatonic_mode(struct autofs_sb_info *);
 153
 154 #ifdef DEBUG
 155 void autofs_say(const char *name, int len);
 156 #else
 157 #define autofs_say(n,l) ((void)0)
 158 #endif