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 dentry *root;
  96         struct file *pipe;
  97         pid_t oz_pgrp;
  98         int catatonic;
  99         int version;
 100         int sub_version;
 101         unsigned long exp_timeout;
 102         int reghost_enabled;
 103         int needs_reghost;
 104         struct super_block *sb;
 105         struct semaphore wq_sem;
 106         spinlock_t fs_lock;
 107         struct autofs_wait_queue *queues; /* Wait queue pointer */
 108 };
 109
 110 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 111 {
 112         return (struct autofs_sb_info *)(sb->s_fs_info);
 113 }
 114
 115 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 116 {
 117         return (struct autofs_info *)(dentry->d_fsdata);
 118 }
 119
 120 /* autofs4_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 autofs4_oz_mode(struct autofs_sb_info *sbi) {
 125         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 126 }
 127
 128 /* Does a dentry have some pending activity? */
 129 static inline int autofs4_ispending(struct dentry *dentry)
 130 {
 131         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 132         int pending = 0;
 133
 134         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 135                 return 1;
 136
 137         if (inf) {
 138                 spin_lock(&inf->sbi->fs_lock);
 139                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 140                 spin_unlock(&inf->sbi->fs_lock);
 141         }
 142
 143         return pending;
 144 }
 145
 146 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 147 {
 148         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 149         return;
 150 }
 151
 152 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 153 void autofs4_free_ino(struct autofs_info *);
 154
 155 /* Expiration */
 156 int is_autofs4_dentry(struct dentry *);
 157 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 158                         struct autofs_sb_info *,
 159                         struct autofs_packet_expire __user *);
 160 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 161                         struct autofs_sb_info *, int __user *);
 162
 163 /* Operations structures */
 164
 165 extern struct inode_operations autofs4_symlink_inode_operations;
 166 extern struct inode_operations autofs4_dir_inode_operations;
 167 extern struct inode_operations autofs4_root_inode_operations;
 168 extern struct file_operations autofs4_dir_operations;
 169 extern struct file_operations autofs4_root_operations;
 170
 171 /* Initializing function */
 172
 173 int autofs4_fill_super(struct super_block *, void *, int);
 174 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 175
 176 /* Queue management functions */
 177
 178 enum autofs_notify
 179 {
 180         NFY_NONE,
 181         NFY_MOUNT,
 182         NFY_EXPIRE
 183 };
 184
 185 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 186 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 187 void autofs4_catatonic_mode(struct autofs_sb_info *);
 188
 189 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 190 {
 191         int res = 0;
 192
 193         while (d_mountpoint(*dentry)) {
 194                 int followed = follow_down(mnt, dentry);
 195                 if (!followed)
 196                         break;
 197                 res = 1;
 198         }
 199         return res;
 200 }
 201
 202 static inline int simple_positive(struct dentry *dentry)
 203 {
 204         return dentry->d_inode && !d_unhashed(dentry);
 205 }
 206
 207 static inline int simple_empty_nolock(struct dentry *dentry)
 208 {
 209         struct dentry *child;
 210         int ret = 0;
 211
 212         list_for_each_entry(child, &dentry->d_subdirs, d_child)
 213                 if (simple_positive(child))
 214                         goto out;
 215         ret = 1;
 216 out:
 217         return ret;
 218 }