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 <asm/uaccess.h>
  30
  31 #ifdef DEBUG
  32 #define DPRINTK(D) (printk D)
  33 #else
  34 #define DPRINTK(D) ((void)0)
  35 #endif
  36
  37 #define AUTOFS_SUPER_MAGIC 0x0187
  38
  39 /*
  40  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  41  * kernel will keep the negative response cached for up to the time given
  42  * here, although the time can be shorter if the kernel throws the dcache
  43  * entry away.  This probably should be settable from user space.
  44  */
  45 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  46
  47 /* Structures associated with the root directory hash table */
  48
  49 #define AUTOFS_HASH_SIZE 67
  50
  51 struct autofs_dir_ent {
  52         int hash;
  53         char *name;
  54         int len;
  55         ino_t ino;
  56         struct dentry *dentry;
  57         /* Linked list of entries */
  58         struct autofs_dir_ent *next;
  59         struct autofs_dir_ent **back;
  60         /* The following entries are for the expiry system */
  61         unsigned long last_usage;
  62         struct list_head exp;
  63 };
  64
  65 struct autofs_dirhash {
  66         struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
  67         struct list_head expiry_head;
  68 };
  69
  70 struct autofs_wait_queue {
  71         wait_queue_head_t queue;
  72         struct autofs_wait_queue *next;
  73         autofs_wqt_t wait_queue_token;
  74         /* We use the following to see what we are waiting for */
  75         int hash;
  76         int len;
  77         char *name;
  78         /* This is for status reporting upon return */
  79         int status;
  80         int wait_ctr;
  81 };
  82
  83 struct autofs_symlink {
  84         char *data;
  85         int len;
  86         time_t mtime;
  87 };
  88
  89 #define AUTOFS_MAX_SYMLINKS 256
  90
  91 #define AUTOFS_ROOT_INO      1
  92 #define AUTOFS_FIRST_SYMLINK 2
  93 #define AUTOFS_FIRST_DIR_INO (AUTOFS_FIRST_SYMLINK+AUTOFS_MAX_SYMLINKS)
  94
  95 #define AUTOFS_SYMLINK_BITMAP_LEN \
  96         ((AUTOFS_MAX_SYMLINKS+((sizeof(long)*1)-1))/(sizeof(long)*8))
  97
  98 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  99
 100 struct autofs_sb_info {
 101         u32 magic;
 102         struct file *pipe;
 103         pid_t oz_pgrp;
 104         int catatonic;
 105         unsigned long exp_timeout;
 106         ino_t next_dir_ino;
 107         struct autofs_wait_queue *queues; /* Wait queue pointer */
 108         struct autofs_dirhash dirhash; /* Root directory hash */
 109         struct autofs_symlink symlink[AUTOFS_MAX_SYMLINKS];
 110         unsigned long symlink_bitmap[AUTOFS_SYMLINK_BITMAP_LEN];
 111 };
 112
 113 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 114 {
 115         return (struct autofs_sb_info *)(sb->s_fs_info);
 116 }
 117
 118 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
 119    processes which do manipulations for us in user space sees the raw
 120    filesystem without "magic".) */
 121
 122 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
 123         return sbi->catatonic || current->pgrp == sbi->oz_pgrp;
 124 }
 125
 126 /* Hash operations */
 127
 128 void autofs_initialize_hash(struct autofs_dirhash *);
 129 struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
 130 void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
 131 void autofs_hash_delete(struct autofs_dir_ent *);
 132 struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
 133 void autofs_hash_dputall(struct autofs_dirhash *);
 134 void autofs_hash_nuke(struct autofs_dirhash *);
 135
 136 /* Expiration-handling functions */
 137
 138 void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
 139 struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *, struct vfsmount *mnt);
 140
 141 /* Operations structures */
 142
 143 extern struct inode_operations autofs_root_inode_operations;
 144 extern struct inode_operations autofs_symlink_inode_operations;
 145 extern struct file_operations autofs_root_operations;
 146
 147 /* Initializing function */
 148
 149 int autofs_fill_super(struct super_block *, void *, int);
 150
 151 /* Queue management functions */
 152
 153 int autofs_wait(struct autofs_sb_info *,struct qstr *);
 154 int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 155 void autofs_catatonic_mode(struct autofs_sb_info *);
 156
 157 #ifdef DEBUG
 158 void autofs_say(const char *name, int len);
 159 #else
 160 #define autofs_say(n,l) ((void)0)
 161 #endif