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         spinlock_t fs_lock;
 106         struct autofs_wait_queue *queues; /* Wait queue pointer */
 107 };
 108
 109 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 110 {
 111         return (struct autofs_sb_info *)(sb->s_fs_info);
 112 }
 113
 114 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 115 {
 116         return (struct autofs_info *)(dentry->d_fsdata);
 117 }
 118
 119 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 120    processes which do manipulations for us in user space sees the raw
 121    filesystem without "magic".) */
 122
 123 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 124         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 125 }
 126
 127 /* Does a dentry have some pending activity? */
 128 static inline int autofs4_ispending(struct dentry *dentry)
 129 {
 130         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 131         int pending = 0;
 132
 133         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 134                 return 1;
 135
 136         if (inf) {
 137                 spin_lock(&inf->sbi->fs_lock);
 138                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 139                 spin_unlock(&inf->sbi->fs_lock);
 140         }
 141
 142         return pending;
 143 }
 144
 145 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 146 {
 147         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 148         return;
 149 }
 150
 151 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 152 void autofs4_free_ino(struct autofs_info *);
 153
 154 /* Expiration */
 155 int is_autofs4_dentry(struct dentry *);
 156 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 157                         struct autofs_sb_info *,
 158                         struct autofs_packet_expire __user *);
 159 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 160                         struct autofs_sb_info *, int __user *);
 161
 162 /* Operations structures */
 163
 164 extern struct inode_operations autofs4_symlink_inode_operations;
 165 extern struct inode_operations autofs4_dir_inode_operations;
 166 extern struct inode_operations autofs4_root_inode_operations;
 167 extern struct file_operations autofs4_dir_operations;
 168 extern struct file_operations autofs4_root_operations;
 169
 170 /* Initializing function */
 171
 172 int autofs4_fill_super(struct super_block *, void *, int);
 173 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 174
 175 /* Queue management functions */
 176
 177 enum autofs_notify
 178 {
 179         NFY_NONE,
 180         NFY_MOUNT,
 181         NFY_EXPIRE
 182 };
 183
 184 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 185 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 186 void autofs4_catatonic_mode(struct autofs_sb_info *);
 187
 188 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 189 {
 190         int res = 0;
 191
 192         while (d_mountpoint(*dentry)) {
 193                 int followed = follow_down(mnt, dentry);
 194                 if (!followed)
 195                         break;
 196                 res = 1;
 197         }
 198         return res;
 199 }
 200
 201 static inline int simple_positive(struct dentry *dentry)
 202 {
 203         return dentry->d_inode && !d_unhashed(dentry);
 204 }
 205
 206 static inline int simple_empty_nolock(struct dentry *dentry)
 207 {
 208         struct dentry *child;
 209         int ret = 0;
 210
 211         list_for_each_entry(child, &dentry->d_subdirs, d_child)
 212                 if (simple_positive(child))
 213                         goto out;
 214         ret = 1;
 215 out:
 216         return ret;
 217 }