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/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
  52 struct 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
  66 struct autofs_dirhash {
  67         struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
  68         struct list_head expiry_head;
  69 };
  70
  71 struct 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
  84 struct 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
 101 struct 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
 115 static 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
 124 static 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
 130 void autofs_initialize_hash(struct autofs_dirhash *);
 131 struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
 132 void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
 133 void autofs_hash_delete(struct autofs_dir_ent *);
 134 struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
 135 void autofs_hash_dputall(struct autofs_dirhash *);
 136 void autofs_hash_nuke(struct autofs_sb_info *);
 137
 138 /* Expiration-handling functions */
 139
 140 void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
 141 struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *, struct vfsmount *mnt);
 142
 143 /* Operations structures */
 144
 145 extern const struct inode_operations autofs_root_inode_operations;
 146 extern const struct inode_operations autofs_symlink_inode_operations;
 147 extern const struct file_operations autofs_root_operations;
 148
 149 /* Initializing function */
 150
 151 int autofs_fill_super(struct super_block *, void *, int);
 152 void autofs_kill_sb(struct super_block *sb);
 153
 154 /* Queue management functions */
 155
 156 int autofs_wait(struct autofs_sb_info *,struct qstr *);
 157 int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 158 void autofs_catatonic_mode(struct autofs_sb_info *);
 159
 160 #ifdef DEBUG
 161 void autofs_say(const char *name, int len);
 162 #else
 163 #define autofs_say(n,l) ((void)0)
 164 #endif