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 rehash;
  56
  57         struct autofs_sb_info *sbi;
  58         unsigned long last_used;
  59         atomic_t count;
  60
  61         mode_t  mode;
  62         size_t  size;
  63
  64         void (*free)(struct autofs_info *);
  65         union {
  66                 const char *symlink;
  67         } u;
  68 };
  69
  70 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  71
  72 struct autofs_wait_queue {
  73         wait_queue_head_t queue;
  74         struct autofs_wait_queue *next;
  75         autofs_wqt_t wait_queue_token;
  76         /* We use the following to see what we are waiting for */
  77         unsigned int hash;
  78         unsigned int len;
  79         char *name;
  80         u32 dev;
  81         u64 ino;
  82         uid_t uid;
  83         gid_t gid;
  84         pid_t pid;
  85         pid_t tgid;
  86         /* This is for status reporting upon return */
  87         int status;
  88         atomic_t wait_ctr;
  89 };
  90
  91 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  92
  93 #define AUTOFS_TYPE_INDIRECT     0x0001
  94 #define AUTOFS_TYPE_DIRECT       0x0002
  95 #define AUTOFS_TYPE_OFFSET       0x0004
  96
  97 struct autofs_sb_info {
  98         u32 magic;
  99         int pipefd;
 100         struct file *pipe;
 101         pid_t oz_pgrp;
 102         int catatonic;
 103         int version;
 104         int sub_version;
 105         int min_proto;
 106         int max_proto;
 107         unsigned long exp_timeout;
 108         unsigned int type;
 109         int reghost_enabled;
 110         int needs_reghost;
 111         struct super_block *sb;
 112         struct mutex wq_mutex;
 113         spinlock_t fs_lock;
 114         struct autofs_wait_queue *queues; /* Wait queue pointer */
 115         spinlock_t rehash_lock;
 116         struct list_head rehash_list;
 117 };
 118
 119 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 120 {
 121         return (struct autofs_sb_info *)(sb->s_fs_info);
 122 }
 123
 124 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 125 {
 126         return (struct autofs_info *)(dentry->d_fsdata);
 127 }
 128
 129 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 130    processes which do manipulations for us in user space sees the raw
 131    filesystem without "magic".) */
 132
 133 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 134         return sbi->catatonic || task_pgrp_nr(current) == sbi->oz_pgrp;
 135 }
 136
 137 /* Does a dentry have some pending activity? */
 138 static inline int autofs4_ispending(struct dentry *dentry)
 139 {
 140         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 141         int pending = 0;
 142
 143         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 144                 return 1;
 145
 146         if (inf) {
 147                 spin_lock(&inf->sbi->fs_lock);
 148                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 149                 spin_unlock(&inf->sbi->fs_lock);
 150         }
 151
 152         return pending;
 153 }
 154
 155 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 156 {
 157         dst->f_path.dentry->d_inode->i_atime =
 158                 src->f_path.dentry->d_inode->i_atime;
 159         return;
 160 }
 161
 162 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 163 void autofs4_free_ino(struct autofs_info *);
 164
 165 /* Expiration */
 166 int is_autofs4_dentry(struct dentry *);
 167 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 168                         struct autofs_sb_info *,
 169                         struct autofs_packet_expire __user *);
 170 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 171                         struct autofs_sb_info *, int __user *);
 172
 173 /* Operations structures */
 174
 175 extern const struct inode_operations autofs4_symlink_inode_operations;
 176 extern const struct inode_operations autofs4_dir_inode_operations;
 177 extern const struct inode_operations autofs4_root_inode_operations;
 178 extern const struct inode_operations autofs4_indirect_root_inode_operations;
 179 extern const struct inode_operations autofs4_direct_root_inode_operations;
 180 extern const struct file_operations autofs4_dir_operations;
 181 extern const struct file_operations autofs4_root_operations;
 182
 183 /* Initializing function */
 184
 185 int autofs4_fill_super(struct super_block *, void *, int);
 186 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 187
 188 /* Queue management functions */
 189
 190 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 191 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 192 void autofs4_catatonic_mode(struct autofs_sb_info *);
 193
 194 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 195 {
 196         int res = 0;
 197
 198         while (d_mountpoint(*dentry)) {
 199                 int followed = follow_down(mnt, dentry);
 200                 if (!followed)
 201                         break;
 202                 res = 1;
 203         }
 204         return res;
 205 }
 206
 207 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 208 {
 209         return new_encode_dev(sbi->sb->s_dev);
 210 }
 211
 212 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 213 {
 214         return sbi->sb->s_root->d_inode->i_ino;
 215 }
 216
 217 static inline int simple_positive(struct dentry *dentry)
 218 {
 219         return dentry->d_inode && !d_unhashed(dentry);
 220 }
 221
 222 static inline int __simple_empty(struct dentry *dentry)
 223 {
 224         struct dentry *child;
 225         int ret = 0;
 226
 227         list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 228                 if (simple_positive(child))
 229                         goto out;
 230         ret = 1;
 231 out:
 232         return ret;
 233 }
 234
 235 void autofs4_dentry_release(struct dentry *);
 236 extern void autofs4_kill_sb(struct super_block *);