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  *   Copyright 2005-2006 Ian Kent <raven@themaw.net>
   7  *
   8  * This file is part of the Linux kernel and is made available under
   9  * the terms of the GNU General Public License, version 2, or at your
  10  * option, any later version, incorporated herein by reference.
  11  *
  12  * ----------------------------------------------------------------------- */
  13
  14 /* Internal header file for autofs */
  15
  16 #include <linux/auto_fs4.h>
  17 #include <linux/mutex.h>
  18 #include <linux/list.h>
  19
  20 /* This is the range of ioctl() numbers we claim as ours */
  21 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  22 #define AUTOFS_IOC_COUNT     32
  23
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/time.h>
  27 #include <linux/string.h>
  28 #include <linux/wait.h>
  29 #include <linux/sched.h>
  30 #include <linux/mount.h>
  31 #include <linux/namei.h>
  32 #include <asm/current.h>
  33 #include <asm/uaccess.h>
  34
  35 /* #define DEBUG */
  36
  37 #ifdef DEBUG
  38 #define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __func__ , ##args); } while(0)
  39 #else
  40 #define DPRINTK(fmt,args...) do {} while(0)
  41 #endif
  42
  43 /* Unified info structure.  This is pointed to by both the dentry and
  44    inode structures.  Each file in the filesystem has an instance of this
  45    structure.  It holds a reference to the dentry, so dentries are never
  46    flushed while the file exists.  All name lookups are dealt with at the
  47    dentry level, although the filesystem can interfere in the validation
  48    process.  Readdir is implemented by traversing the dentry lists. */
  49 struct autofs_info {
  50         struct dentry   *dentry;
  51         struct inode    *inode;
  52
  53         int             flags;
  54
  55         struct list_head active;
  56         struct list_head expiring;
  57
  58         struct autofs_sb_info *sbi;
  59         unsigned long last_used;
  60         atomic_t count;
  61
  62         mode_t  mode;
  63         size_t  size;
  64
  65         void (*free)(struct autofs_info *);
  66         union {
  67                 const char *symlink;
  68         } u;
  69 };
  70
  71 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  72
  73 struct autofs_wait_queue {
  74         wait_queue_head_t queue;
  75         struct autofs_wait_queue *next;
  76         autofs_wqt_t wait_queue_token;
  77         /* We use the following to see what we are waiting for */
  78         unsigned int hash;
  79         unsigned int len;
  80         char *name;
  81         u32 dev;
  82         u64 ino;
  83         uid_t uid;
  84         gid_t gid;
  85         pid_t pid;
  86         pid_t tgid;
  87         /* This is for status reporting upon return */
  88         int status;
  89         atomic_t wait_ctr;
  90 };
  91
  92 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  93
  94 #define AUTOFS_TYPE_INDIRECT     0x0001
  95 #define AUTOFS_TYPE_DIRECT       0x0002
  96 #define AUTOFS_TYPE_OFFSET       0x0004
  97
  98 struct autofs_sb_info {
  99         u32 magic;
 100         int pipefd;
 101         struct file *pipe;
 102         pid_t oz_pgrp;
 103         int catatonic;
 104         int version;
 105         int sub_version;
 106         int min_proto;
 107         int max_proto;
 108         unsigned long exp_timeout;
 109         unsigned int type;
 110         int reghost_enabled;
 111         int needs_reghost;
 112         struct super_block *sb;
 113         struct mutex wq_mutex;
 114         spinlock_t fs_lock;
 115         struct autofs_wait_queue *queues; /* Wait queue pointer */
 116         spinlock_t lookup_lock;
 117         struct list_head active_list;
 118         struct list_head expiring_list;
 119 };
 120
 121 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 122 {
 123         return (struct autofs_sb_info *)(sb->s_fs_info);
 124 }
 125
 126 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 127 {
 128         return (struct autofs_info *)(dentry->d_fsdata);
 129 }
 130
 131 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 132    processes which do manipulations for us in user space sees the raw
 133    filesystem without "magic".) */
 134
 135 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 136         return sbi->catatonic || task_pgrp_nr(current) == sbi->oz_pgrp;
 137 }
 138
 139 /* Does a dentry have some pending activity? */
 140 static inline int autofs4_ispending(struct dentry *dentry)
 141 {
 142         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 143         int pending = 0;
 144
 145         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 146                 return 1;
 147
 148         if (inf) {
 149                 spin_lock(&inf->sbi->fs_lock);
 150                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 151                 spin_unlock(&inf->sbi->fs_lock);
 152         }
 153
 154         return pending;
 155 }
 156
 157 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 158 {
 159         dst->f_path.dentry->d_inode->i_atime =
 160                 src->f_path.dentry->d_inode->i_atime;
 161         return;
 162 }
 163
 164 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 165 void autofs4_free_ino(struct autofs_info *);
 166
 167 /* Expiration */
 168 int is_autofs4_dentry(struct dentry *);
 169 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 170                         struct autofs_sb_info *,
 171                         struct autofs_packet_expire __user *);
 172 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 173                         struct autofs_sb_info *, int __user *);
 174
 175 /* Operations structures */
 176
 177 extern const struct inode_operations autofs4_symlink_inode_operations;
 178 extern const struct inode_operations autofs4_dir_inode_operations;
 179 extern const struct inode_operations autofs4_root_inode_operations;
 180 extern const struct inode_operations autofs4_indirect_root_inode_operations;
 181 extern const struct inode_operations autofs4_direct_root_inode_operations;
 182 extern const struct file_operations autofs4_dir_operations;
 183 extern const struct file_operations autofs4_root_operations;
 184
 185 /* Initializing function */
 186
 187 int autofs4_fill_super(struct super_block *, void *, int);
 188 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 189
 190 /* Queue management functions */
 191
 192 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 193 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 194 void autofs4_catatonic_mode(struct autofs_sb_info *);
 195
 196 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 197 {
 198         int res = 0;
 199
 200         while (d_mountpoint(*dentry)) {
 201                 int followed = follow_down(mnt, dentry);
 202                 if (!followed)
 203                         break;
 204                 res = 1;
 205         }
 206         return res;
 207 }
 208
 209 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 210 {
 211         return new_encode_dev(sbi->sb->s_dev);
 212 }
 213
 214 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 215 {
 216         return sbi->sb->s_root->d_inode->i_ino;
 217 }
 218
 219 static inline int simple_positive(struct dentry *dentry)
 220 {
 221         return dentry->d_inode && !d_unhashed(dentry);
 222 }
 223
 224 static inline int __simple_empty(struct dentry *dentry)
 225 {
 226         struct dentry *child;
 227         int ret = 0;
 228
 229         list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 230                 if (simple_positive(child))
 231                         goto out;
 232         ret = 1;
 233 out:
 234         return ret;
 235 }
 236
 237 void autofs4_dentry_release(struct dentry *);
 238 extern void autofs4_kill_sb(struct super_block *);