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 #include <linux/magic.h>
  22
  23 /* This is the range of ioctl() numbers we claim as ours */
  24 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  25 #define AUTOFS_IOC_COUNT     32
  26
  27 #define AUTOFS_DEV_IOCTL_IOC_FIRST      (AUTOFS_DEV_IOCTL_VERSION)
  28 #define AUTOFS_DEV_IOCTL_IOC_COUNT      (AUTOFS_IOC_COUNT - 11)
  29
  30 #include <linux/kernel.h>
  31 #include <linux/slab.h>
  32 #include <linux/time.h>
  33 #include <linux/string.h>
  34 #include <linux/wait.h>
  35 #include <linux/sched.h>
  36 #include <linux/mount.h>
  37 #include <linux/namei.h>
  38 #include <asm/current.h>
  39 #include <asm/uaccess.h>
  40
  41 /* #define DEBUG */
  42
  43 #define DPRINTK(fmt, ...)                               \
  44         pr_debug("pid %d: %s: " fmt "\n",               \
  45                 current->pid, __func__, ##__VA_ARGS__)
  46
  47 #define AUTOFS_WARN(fmt, ...)                           \
  48         printk(KERN_WARNING "pid %d: %s: " fmt "\n",    \
  49                 current->pid, __func__, ##__VA_ARGS__)
  50
  51 #define AUTOFS_ERROR(fmt, ...)                          \
  52         printk(KERN_ERR "pid %d: %s: " fmt "\n",        \
  53                 current->pid, __func__, ##__VA_ARGS__)
  54
  55 /* Unified info structure.  This is pointed to by both the dentry and
  56    inode structures.  Each file in the filesystem has an instance of this
  57    structure.  It holds a reference to the dentry, so dentries are never
  58    flushed while the file exists.  All name lookups are dealt with at the
  59    dentry level, although the filesystem can interfere in the validation
  60    process.  Readdir is implemented by traversing the dentry lists. */
  61 struct autofs_info {
  62         struct dentry   *dentry;
  63         struct inode    *inode;
  64
  65         int             flags;
  66
  67         struct completion expire_complete;
  68
  69         struct list_head active;
  70         int active_count;
  71
  72         struct list_head expiring;
  73
  74         struct autofs_sb_info *sbi;
  75         unsigned long last_used;
  76         atomic_t count;
  77
  78         kuid_t uid;
  79         kgid_t gid;
  80 };
  81
  82 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  83 #define AUTOFS_INF_WANT_EXPIRE  (1<<1) /* the dentry is being considered
  84                                         * for expiry, so RCU_walk is
  85                                         * not permitted.  If it progresses to
  86                                         * actual expiry attempt, the flag is
  87                                         * not cleared when EXPIRING is set -
  88                                         * in that case it gets cleared only
  89                                         * when it comes to clearing EXPIRING.
  90                                         */
  91 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  92
  93 struct autofs_wait_queue {
  94         wait_queue_head_t queue;
  95         struct autofs_wait_queue *next;
  96         autofs_wqt_t wait_queue_token;
  97         /* We use the following to see what we are waiting for */
  98         struct qstr name;
  99         u32 dev;
 100         u64 ino;
 101         kuid_t uid;
 102         kgid_t gid;
 103         pid_t pid;
 104         pid_t tgid;
 105         /* This is for status reporting upon return */
 106         int status;
 107         unsigned int wait_ctr;
 108 };
 109
 110 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 111
 112 struct autofs_sb_info {
 113         u32 magic;
 114         int pipefd;
 115         struct file *pipe;
 116         struct pid *oz_pgrp;
 117         int catatonic;
 118         int version;
 119         int sub_version;
 120         int min_proto;
 121         int max_proto;
 122         unsigned long exp_timeout;
 123         unsigned int type;
 124         int reghost_enabled;
 125         int needs_reghost;
 126         struct super_block *sb;
 127         struct mutex wq_mutex;
 128         struct mutex pipe_mutex;
 129         spinlock_t fs_lock;
 130         struct autofs_wait_queue *queues; /* Wait queue pointer */
 131         spinlock_t lookup_lock;
 132         struct list_head active_list;
 133         struct list_head expiring_list;
 134         struct rcu_head rcu;
 135 };
 136
 137 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 138 {
 139         return sb->s_magic != AUTOFS_SUPER_MAGIC ?
 140                 NULL : (struct autofs_sb_info *)(sb->s_fs_info);
 141 }
 142
 143 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 144 {
 145         return (struct autofs_info *)(dentry->d_fsdata);
 146 }
 147
 148 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 149    processes which do manipulations for us in user space sees the raw
 150    filesystem without "magic".) */
 151
 152 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 153         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 154 }
 155
 156 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 157 void autofs4_free_ino(struct autofs_info *);
 158
 159 /* Expiration */
 160 int is_autofs4_dentry(struct dentry *);
 161 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 162 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 163                         struct autofs_sb_info *,
 164                         struct autofs_packet_expire __user *);
 165 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 166                             struct autofs_sb_info *sbi, int when);
 167 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 168                         struct autofs_sb_info *, int __user *);
 169 struct dentry *autofs4_expire_direct(struct super_block *sb,
 170                                      struct vfsmount *mnt,
 171                                      struct autofs_sb_info *sbi, int how);
 172 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 173                                        struct vfsmount *mnt,
 174                                        struct autofs_sb_info *sbi, int how);
 175
 176 /* Device node initialization */
 177
 178 int autofs_dev_ioctl_init(void);
 179 void autofs_dev_ioctl_exit(void);
 180
 181 /* Operations structures */
 182
 183 extern const struct inode_operations autofs4_symlink_inode_operations;
 184 extern const struct inode_operations autofs4_dir_inode_operations;
 185 extern const struct file_operations autofs4_dir_operations;
 186 extern const struct file_operations autofs4_root_operations;
 187 extern const struct dentry_operations autofs4_dentry_operations;
 188
 189 /* VFS automount flags management functions */
 190 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 191 {
 192         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 193 }
 194
 195 static inline void managed_dentry_set_managed(struct dentry *dentry)
 196 {
 197         spin_lock(&dentry->d_lock);
 198         __managed_dentry_set_managed(dentry);
 199         spin_unlock(&dentry->d_lock);
 200 }
 201
 202 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 203 {
 204         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 205 }
 206
 207 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 208 {
 209         spin_lock(&dentry->d_lock);
 210         __managed_dentry_clear_managed(dentry);
 211         spin_unlock(&dentry->d_lock);
 212 }
 213
 214 /* Initializing function */
 215
 216 int autofs4_fill_super(struct super_block *, void *, int);
 217 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 218 void autofs4_clean_ino(struct autofs_info *);
 219
 220 static inline int autofs_prepare_pipe(struct file *pipe)
 221 {
 222         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 223                 return -EINVAL;
 224         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 225                 return -EINVAL;
 226         /* We want a packet pipe */
 227         pipe->f_flags |= O_DIRECT;
 228         return 0;
 229 }
 230
 231 /* Queue management functions */
 232
 233 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 234 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 235 void autofs4_catatonic_mode(struct autofs_sb_info *);
 236
 237 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 238 {
 239         return new_encode_dev(sbi->sb->s_dev);
 240 }
 241
 242 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 243 {
 244         return d_inode(sbi->sb->s_root)->i_ino;
 245 }
 246
 247 static inline void __autofs4_add_expiring(struct dentry *dentry)
 248 {
 249         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 250         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 251         if (ino) {
 252                 if (list_empty(&ino->expiring))
 253                         list_add(&ino->expiring, &sbi->expiring_list);
 254         }
 255         return;
 256 }
 257
 258 static inline void autofs4_add_expiring(struct dentry *dentry)
 259 {
 260         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 261         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 262         if (ino) {
 263                 spin_lock(&sbi->lookup_lock);
 264                 if (list_empty(&ino->expiring))
 265                         list_add(&ino->expiring, &sbi->expiring_list);
 266                 spin_unlock(&sbi->lookup_lock);
 267         }
 268         return;
 269 }
 270
 271 static inline void autofs4_del_expiring(struct dentry *dentry)
 272 {
 273         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 274         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 275         if (ino) {
 276                 spin_lock(&sbi->lookup_lock);
 277                 if (!list_empty(&ino->expiring))
 278                         list_del_init(&ino->expiring);
 279                 spin_unlock(&sbi->lookup_lock);
 280         }
 281         return;
 282 }
 283
 284 extern void autofs4_kill_sb(struct super_block *);