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/auto_dev-ioctl.h>
  18 #include <linux/mutex.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/list.h>
  21
  22 /* This is the range of ioctl() numbers we claim as ours */
  23 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  24 #define AUTOFS_IOC_COUNT     32
  25
  26 #define AUTOFS_DEV_IOCTL_IOC_FIRST      (AUTOFS_DEV_IOCTL_VERSION)
  27 #define AUTOFS_DEV_IOCTL_IOC_COUNT      (AUTOFS_IOC_COUNT - 11)
  28
  29 #include <linux/kernel.h>
  30 #include <linux/slab.h>
  31 #include <linux/time.h>
  32 #include <linux/string.h>
  33 #include <linux/wait.h>
  34 #include <linux/sched.h>
  35 #include <linux/mount.h>
  36 #include <linux/namei.h>
  37 #include <asm/current.h>
  38 #include <asm/uaccess.h>
  39
  40 /* #define DEBUG */
  41
  42 #define DPRINTK(fmt, ...)                               \
  43         pr_debug("pid %d: %s: " fmt "\n",               \
  44                 current->pid, __func__, ##__VA_ARGS__)
  45
  46 #define AUTOFS_WARN(fmt, ...)                           \
  47         printk(KERN_WARNING "pid %d: %s: " fmt "\n",    \
  48                 current->pid, __func__, ##__VA_ARGS__)
  49
  50 #define AUTOFS_ERROR(fmt, ...)                          \
  51         printk(KERN_ERR "pid %d: %s: " fmt "\n",        \
  52                 current->pid, __func__, ##__VA_ARGS__)
  53
  54 /* Unified info structure.  This is pointed to by both the dentry and
  55    inode structures.  Each file in the filesystem has an instance of this
  56    structure.  It holds a reference to the dentry, so dentries are never
  57    flushed while the file exists.  All name lookups are dealt with at the
  58    dentry level, although the filesystem can interfere in the validation
  59    process.  Readdir is implemented by traversing the dentry lists. */
  60 struct autofs_info {
  61         struct dentry   *dentry;
  62         struct inode    *inode;
  63
  64         int             flags;
  65
  66         struct completion expire_complete;
  67
  68         struct list_head active;
  69         int active_count;
  70
  71         struct list_head expiring;
  72
  73         struct autofs_sb_info *sbi;
  74         unsigned long last_used;
  75         atomic_t count;
  76
  77         kuid_t uid;
  78         kgid_t gid;
  79 };
  80
  81 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  82 #define AUTOFS_INF_NO_RCU       (1<<1) /* the dentry is being considered
  83                                         * for expiry, so RCU_walk is
  84                                         * not permitted
  85                                         */
  86 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  87
  88 struct autofs_wait_queue {
  89         wait_queue_head_t queue;
  90         struct autofs_wait_queue *next;
  91         autofs_wqt_t wait_queue_token;
  92         /* We use the following to see what we are waiting for */
  93         struct qstr name;
  94         u32 dev;
  95         u64 ino;
  96         kuid_t uid;
  97         kgid_t gid;
  98         pid_t pid;
  99         pid_t tgid;
 100         /* This is for status reporting upon return */
 101         int status;
 102         unsigned int wait_ctr;
 103 };
 104
 105 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 106
 107 struct autofs_sb_info {
 108         u32 magic;
 109         int pipefd;
 110         struct file *pipe;
 111         struct pid *oz_pgrp;
 112         int catatonic;
 113         int version;
 114         int sub_version;
 115         int min_proto;
 116         int max_proto;
 117         unsigned long exp_timeout;
 118         unsigned int type;
 119         int reghost_enabled;
 120         int needs_reghost;
 121         struct super_block *sb;
 122         struct mutex wq_mutex;
 123         struct mutex pipe_mutex;
 124         spinlock_t fs_lock;
 125         struct autofs_wait_queue *queues; /* Wait queue pointer */
 126         spinlock_t lookup_lock;
 127         struct list_head active_list;
 128         struct list_head expiring_list;
 129         struct rcu_head rcu;
 130 };
 131
 132 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 133 {
 134         return (struct autofs_sb_info *)(sb->s_fs_info);
 135 }
 136
 137 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 138 {
 139         return (struct autofs_info *)(dentry->d_fsdata);
 140 }
 141
 142 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 143    processes which do manipulations for us in user space sees the raw
 144    filesystem without "magic".) */
 145
 146 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 147         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 148 }
 149
 150 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 151 void autofs4_free_ino(struct autofs_info *);
 152
 153 /* Expiration */
 154 int is_autofs4_dentry(struct dentry *);
 155 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 156 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 157                         struct autofs_sb_info *,
 158                         struct autofs_packet_expire __user *);
 159 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 160                             struct autofs_sb_info *sbi, int when);
 161 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 162                         struct autofs_sb_info *, int __user *);
 163 struct dentry *autofs4_expire_direct(struct super_block *sb,
 164                                      struct vfsmount *mnt,
 165                                      struct autofs_sb_info *sbi, int how);
 166 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 167                                        struct vfsmount *mnt,
 168                                        struct autofs_sb_info *sbi, int how);
 169
 170 /* Device node initialization */
 171
 172 int autofs_dev_ioctl_init(void);
 173 void autofs_dev_ioctl_exit(void);
 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 file_operations autofs4_dir_operations;
 180 extern const struct file_operations autofs4_root_operations;
 181 extern const struct dentry_operations autofs4_dentry_operations;
 182
 183 /* VFS automount flags management functions */
 184 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 185 {
 186         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 187 }
 188
 189 static inline void managed_dentry_set_managed(struct dentry *dentry)
 190 {
 191         spin_lock(&dentry->d_lock);
 192         __managed_dentry_set_managed(dentry);
 193         spin_unlock(&dentry->d_lock);
 194 }
 195
 196 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 197 {
 198         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 199 }
 200
 201 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 202 {
 203         spin_lock(&dentry->d_lock);
 204         __managed_dentry_clear_managed(dentry);
 205         spin_unlock(&dentry->d_lock);
 206 }
 207
 208 /* Initializing function */
 209
 210 int autofs4_fill_super(struct super_block *, void *, int);
 211 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 212 void autofs4_clean_ino(struct autofs_info *);
 213
 214 static inline int autofs_prepare_pipe(struct file *pipe)
 215 {
 216         if (!pipe->f_op->write)
 217                 return -EINVAL;
 218         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 219                 return -EINVAL;
 220         /* We want a packet pipe */
 221         pipe->f_flags |= O_DIRECT;
 222         return 0;
 223 }
 224
 225 /* Queue management functions */
 226
 227 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 228 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 229 void autofs4_catatonic_mode(struct autofs_sb_info *);
 230
 231 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 232 {
 233         return new_encode_dev(sbi->sb->s_dev);
 234 }
 235
 236 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 237 {
 238         return sbi->sb->s_root->d_inode->i_ino;
 239 }
 240
 241 static inline int simple_positive(struct dentry *dentry)
 242 {
 243         return dentry->d_inode && !d_unhashed(dentry);
 244 }
 245
 246 static inline void __autofs4_add_expiring(struct dentry *dentry)
 247 {
 248         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 249         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 250         if (ino) {
 251                 if (list_empty(&ino->expiring))
 252                         list_add(&ino->expiring, &sbi->expiring_list);
 253         }
 254         return;
 255 }
 256
 257 static inline void autofs4_add_expiring(struct dentry *dentry)
 258 {
 259         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 260         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 261         if (ino) {
 262                 spin_lock(&sbi->lookup_lock);
 263                 if (list_empty(&ino->expiring))
 264                         list_add(&ino->expiring, &sbi->expiring_list);
 265                 spin_unlock(&sbi->lookup_lock);
 266         }
 267         return;
 268 }
 269
 270 static inline void autofs4_del_expiring(struct dentry *dentry)
 271 {
 272         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 273         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 274         if (ino) {
 275                 spin_lock(&sbi->lookup_lock);
 276                 if (!list_empty(&ino->expiring))
 277                         list_del_init(&ino->expiring);
 278                 spin_unlock(&sbi->lookup_lock);
 279         }
 280         return;
 281 }
 282
 283 extern void autofs4_kill_sb(struct super_block *);