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 #define AUTOFS_SUPER_MAGIC 0x0187
  41
  42 /*
  43  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  44  * kernel will keep the negative response cached for up to the time given
  45  * here, although the time can be shorter if the kernel throws the dcache
  46  * entry away.  This probably should be settable from user space.
  47  */
  48 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  49
  50 /* Structures associated with the root directory hash table */
  51
  52 #define AUTOFS_HASH_SIZE 67
  53
  54 struct autofs_dir_ent {
  55         int hash;
  56         char *name;
  57         int len;
  58         ino_t ino;
  59         struct dentry *dentry;
  60         /* Linked list of entries */
  61         struct autofs_dir_ent *next;
  62         struct autofs_dir_ent **back;
  63         /* The following entries are for the expiry system */
  64         unsigned long last_usage;
  65         struct list_head exp;
  66 };
  67
  68 struct autofs_dirhash {
  69         struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
  70         struct list_head expiry_head;
  71 };
  72
  73 struct autofs_wait_queue {
  74         wait_queue_head_t queue;
  75         struct autofs_wait_queue *next;
  76         autofs_wqt_t wait_queue_token;
  77         /* We use the following to see what we are waiting for */
  78         int hash;
  79         int len;
  80         char *name;
  81         /* This is for status reporting upon return */
  82         int status;
  83         int wait_ctr;
  84 };
  85
  86 struct autofs_symlink {
  87         char *data;
  88         int len;
  89         time_t mtime;
  90 };
  91
  92 #define AUTOFS_MAX_SYMLINKS 256
  93
  94 #define AUTOFS_ROOT_INO      1
  95 #define AUTOFS_FIRST_SYMLINK 2
  96 #define AUTOFS_FIRST_DIR_INO (AUTOFS_FIRST_SYMLINK+AUTOFS_MAX_SYMLINKS)
  97
  98 #define AUTOFS_SYMLINK_BITMAP_LEN \
  99         ((AUTOFS_MAX_SYMLINKS+((sizeof(long)*1)-1))/(sizeof(long)*8))
 100
 101 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 102
 103 struct autofs_sb_info {
 104         u32 magic;
 105         struct file *pipe;
 106         pid_t oz_pgrp;
 107         int catatonic;
 108         struct super_block *sb;
 109         unsigned long exp_timeout;
 110         ino_t next_dir_ino;
 111         struct autofs_wait_queue *queues; /* Wait queue pointer */
 112         struct autofs_dirhash dirhash; /* Root directory hash */
 113         struct autofs_symlink symlink[AUTOFS_MAX_SYMLINKS];
 114         unsigned long symlink_bitmap[AUTOFS_SYMLINK_BITMAP_LEN];
 115 };
 116
 117 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 118 {
 119         return (struct autofs_sb_info *)(sb->s_fs_info);
 120 }
 121
 122 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
 123    processes which do manipulations for us in user space sees the raw
 124    filesystem without "magic".) */
 125
 126 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
 127         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 128 }
 129
 130 /* Hash operations */
 131
 132 void autofs_initialize_hash(struct autofs_dirhash *);
 133 struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
 134 void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
 135 void autofs_hash_delete(struct autofs_dir_ent *);
 136 struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
 137 void autofs_hash_dputall(struct autofs_dirhash *);
 138 void autofs_hash_nuke(struct autofs_sb_info *);
 139
 140 /* Expiration-handling functions */
 141
 142 void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
 143 struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *, struct vfsmount *mnt);
 144
 145 /* Operations structures */
 146
 147 extern struct inode_operations autofs_root_inode_operations;
 148 extern struct inode_operations autofs_symlink_inode_operations;
 149 extern const struct file_operations autofs_root_operations;
 150
 151 /* Initializing function */
 152
 153 int autofs_fill_super(struct super_block *, void *, int);
 154
 155 /* Queue management functions */
 156
 157 int autofs_wait(struct autofs_sb_info *,struct qstr *);
 158 int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 159 void autofs_catatonic_mode(struct autofs_sb_info *);
 160
 161 #ifdef DEBUG
 162 void autofs_say(const char *name, int len);
 163 #else
 164 #define autofs_say(n,l) ((void)0)
 165 #endif