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/mutex.h>
  17 #include <linux/list.h>
  18
  19 /* This is the range of ioctl() numbers we claim as ours */
  20 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  21 #define AUTOFS_IOC_COUNT     32
  22
  23 #include <linux/kernel.h>
  24 #include <linux/slab.h>
  25 #include <linux/time.h>
  26 #include <linux/string.h>
  27 #include <linux/wait.h>
  28 #include <linux/sched.h>
  29 #include <linux/mount.h>
  30 #include <linux/namei.h>
  31 #include <asm/current.h>
  32 #include <asm/uaccess.h>
  33
  34 /* #define DEBUG */
  35
  36 #ifdef DEBUG
  37 #define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
  38 #else
  39 #define DPRINTK(fmt,args...) do {} while(0)
  40 #endif
  41
  42 #define AUTOFS_SUPER_MAGIC 0x0187
  43
  44 /* Unified info structure.  This is pointed to by both the dentry and
  45    inode structures.  Each file in the filesystem has an instance of this
  46    structure.  It holds a reference to the dentry, so dentries are never
  47    flushed while the file exists.  All name lookups are dealt with at the
  48    dentry level, although the filesystem can interfere in the validation
  49    process.  Readdir is implemented by traversing the dentry lists. */
  50 struct autofs_info {
  51         struct dentry   *dentry;
  52         struct inode    *inode;
  53
  54         int             flags;
  55
  56         struct autofs_sb_info *sbi;
  57         unsigned long last_used;
  58         atomic_t count;
  59
  60         mode_t  mode;
  61         size_t  size;
  62
  63         void (*free)(struct autofs_info *);
  64         union {
  65                 const char *symlink;
  66         } u;
  67 };
  68
  69 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  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         atomic_t notified;
  82         atomic_t wait_ctr;
  83 };
  84
  85 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  86
  87 struct autofs_sb_info {
  88         u32 magic;
  89         struct dentry *root;
  90         int pipefd;
  91         struct file *pipe;
  92         pid_t oz_pgrp;
  93         int catatonic;
  94         int version;
  95         int sub_version;
  96         int min_proto;
  97         int max_proto;
  98         unsigned long exp_timeout;
  99         int reghost_enabled;
 100         int needs_reghost;
 101         struct super_block *sb;
 102         struct mutex wq_mutex;
 103         spinlock_t fs_lock;
 104         struct autofs_wait_queue *queues; /* Wait queue pointer */
 105 };
 106
 107 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 108 {
 109         return (struct autofs_sb_info *)(sb->s_fs_info);
 110 }
 111
 112 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 113 {
 114         return (struct autofs_info *)(dentry->d_fsdata);
 115 }
 116
 117 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 118    processes which do manipulations for us in user space sees the raw
 119    filesystem without "magic".) */
 120
 121 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 122         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 123 }
 124
 125 /* Does a dentry have some pending activity? */
 126 static inline int autofs4_ispending(struct dentry *dentry)
 127 {
 128         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 129         int pending = 0;
 130
 131         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 132                 return 1;
 133
 134         if (inf) {
 135                 spin_lock(&inf->sbi->fs_lock);
 136                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 137                 spin_unlock(&inf->sbi->fs_lock);
 138         }
 139
 140         return pending;
 141 }
 142
 143 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 144 {
 145         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 146         return;
 147 }
 148
 149 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 150 void autofs4_free_ino(struct autofs_info *);
 151
 152 /* Expiration */
 153 int is_autofs4_dentry(struct dentry *);
 154 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 155                         struct autofs_sb_info *,
 156                         struct autofs_packet_expire __user *);
 157 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 158                         struct autofs_sb_info *, int __user *);
 159
 160 /* Operations structures */
 161
 162 extern struct inode_operations autofs4_symlink_inode_operations;
 163 extern struct inode_operations autofs4_dir_inode_operations;
 164 extern struct inode_operations autofs4_root_inode_operations;
 165 extern struct file_operations autofs4_dir_operations;
 166 extern struct file_operations autofs4_root_operations;
 167
 168 /* Initializing function */
 169
 170 int autofs4_fill_super(struct super_block *, void *, int);
 171 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 172
 173 /* Queue management functions */
 174
 175 enum autofs_notify
 176 {
 177         NFY_NONE,
 178         NFY_MOUNT,
 179         NFY_EXPIRE
 180 };
 181
 182 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 183 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 184 void autofs4_catatonic_mode(struct autofs_sb_info *);
 185
 186 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 187 {
 188         int res = 0;
 189
 190         while (d_mountpoint(*dentry)) {
 191                 int followed = follow_down(mnt, dentry);
 192                 if (!followed)
 193                         break;
 194                 res = 1;
 195         }
 196         return res;
 197 }
 198
 199 static inline int simple_positive(struct dentry *dentry)
 200 {
 201         return dentry->d_inode && !d_unhashed(dentry);
 202 }
 203
 204 static inline int __simple_empty(struct dentry *dentry)
 205 {
 206         struct dentry *child;
 207         int ret = 0;
 208
 209         list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 210                 if (simple_positive(child))
 211                         goto out;
 212         ret = 1;
 213 out:
 214         return ret;
 215 }