fs/autofs4/autofs_i.h

   1 /* -*- 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_fs4.h>
  16 #include <linux/list.h>
  17
  18 /* This is the range of ioctl() numbers we claim as ours */
  19 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  20 #define AUTOFS_IOC_COUNT     32
  21
  22 #include <linux/kernel.h>
  23 #include <linux/slab.h>
  24 #include <linux/time.h>
  25 #include <linux/string.h>
  26 #include <linux/wait.h>
  27 #include <linux/sched.h>
  28 #include <linux/mount.h>
  29 #include <linux/namei.h>
  30 #include <asm/current.h>
  31 #include <asm/uaccess.h>
  32
  33 /* #define DEBUG */
  34
  35 #ifdef DEBUG
  36 #define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
  37 #else
  38 #define DPRINTK(fmt,args...) do {} while(0)
  39 #endif
  40
  41 #define AUTOFS_SUPER_MAGIC 0x0187
  42
  43 /*
  44  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  45  * kernel will keep the negative response cached for up to the time given
  46  * here, although the time can be shorter if the kernel throws the dcache
  47  * entry away.  This probably should be settable from user space.
  48  */
  49 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  50
  51 /* Unified info structure.  This is pointed to by both the dentry and
  52    inode structures.  Each file in the filesystem has an instance of this
  53    structure.  It holds a reference to the dentry, so dentries are never
  54    flushed while the file exists.  All name lookups are dealt with at the
  55    dentry level, although the filesystem can interfere in the validation
  56    process.  Readdir is implemented by traversing the dentry lists. */
  57 struct autofs_info {
  58         struct dentry   *dentry;
  59         struct inode    *inode;
  60
  61         int             flags;
  62
  63         struct autofs_sb_info *sbi;
  64         unsigned long last_used;
  65
  66         mode_t  mode;
  67         size_t  size;
  68
  69         void (*free)(struct autofs_info *);
  70         union {
  71                 const char *symlink;
  72         } u;
  73 };
  74
  75 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  76
  77 struct autofs_wait_queue {
  78         wait_queue_head_t queue;
  79         struct autofs_wait_queue *next;
  80         autofs_wqt_t wait_queue_token;
  81         /* We use the following to see what we are waiting for */
  82         int hash;
  83         int len;
  84         char *name;
  85         /* This is for status reporting upon return */
  86         int status;
  87         atomic_t notified;
  88         atomic_t wait_ctr;
  89 };
  90
  91 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  92
  93 struct autofs_sb_info {
  94         u32 magic;
  95         struct file *pipe;
  96         pid_t oz_pgrp;
  97         int catatonic;
  98         int version;
  99         int sub_version;
 100         unsigned long exp_timeout;
 101         int reghost_enabled;
 102         int needs_reghost;
 103         struct super_block *sb;
 104         struct semaphore wq_sem;
 105         struct autofs_wait_queue *queues; /* Wait queue pointer */
 106 };
 107
 108 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 109 {
 110         return (struct autofs_sb_info *)(sb->s_fs_info);
 111 }
 112
 113 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 114 {
 115         return (struct autofs_info *)(dentry->d_fsdata);
 116 }
 117
 118 /* autofs4_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 autofs4_oz_mode(struct autofs_sb_info *sbi) {
 123         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 124 }
 125
 126 /* Does a dentry have some pending activity? */
 127 static inline int autofs4_ispending(struct dentry *dentry)
 128 {
 129         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 130
 131         return (dentry->d_flags & DCACHE_AUTOFS_PENDING) ||
 132                 (inf != NULL && inf->flags & AUTOFS_INF_EXPIRING);
 133 }
 134
 135 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 136 {
 137         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 138         return;
 139 }
 140
 141 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 142 void autofs4_free_ino(struct autofs_info *);
 143
 144 /* Expiration */
 145 int is_autofs4_dentry(struct dentry *);
 146 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 147                         struct autofs_sb_info *,
 148                         struct autofs_packet_expire __user *);
 149 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 150                         struct autofs_sb_info *, int __user *);
 151
 152 /* Operations structures */
 153
 154 extern struct inode_operations autofs4_symlink_inode_operations;
 155 extern struct inode_operations autofs4_dir_inode_operations;
 156 extern struct inode_operations autofs4_root_inode_operations;
 157 extern struct file_operations autofs4_dir_operations;
 158 extern struct file_operations autofs4_root_operations;
 159
 160 /* Initializing function */
 161
 162 int autofs4_fill_super(struct super_block *, void *, int);
 163 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 164
 165 /* Queue management functions */
 166
 167 enum autofs_notify
 168 {
 169         NFY_NONE,
 170         NFY_MOUNT,
 171         NFY_EXPIRE
 172 };
 173
 174 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 175 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 176 void autofs4_catatonic_mode(struct autofs_sb_info *);
 177
 178 static inline int simple_positive(struct dentry *dentry)
 179 {
 180         return dentry->d_inode && !d_unhashed(dentry);
 181 }
 182
 183 static inline int simple_empty_nolock(struct dentry *dentry)
 184 {
 185         struct dentry *child;
 186         int ret = 0;
 187
 188         list_for_each_entry(child, &dentry->d_subdirs, d_child)
 189                 if (simple_positive(child))
 190                         goto out;
 191         ret = 1;
 192 out:
 193         return ret;
 194 }