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_WANT_EXPIRE  (1<<1) /* the dentry is being considered
  83                                         * for expiry, so RCU_walk is
  84                                         * not permitted.  If it progresses to
  85                                         * actual expiry attempt, the flag is
  86                                         * not cleared when EXPIRING is set -
  87                                         * in that case it gets cleared only
  88                                         * when it comes to clearing EXPIRING.
  89                                         */
  90 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  91
  92 struct autofs_wait_queue {
  93         wait_queue_head_t queue;
  94         struct autofs_wait_queue *next;
  95         autofs_wqt_t wait_queue_token;
  96         /* We use the following to see what we are waiting for */
  97         struct qstr name;
  98         u32 dev;
  99         u64 ino;
 100         kuid_t uid;
 101         kgid_t gid;
 102         pid_t pid;
 103         pid_t tgid;
 104         /* This is for status reporting upon return */
 105         int status;
 106         unsigned int wait_ctr;
 107 };
 108
 109 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 110
 111 struct autofs_sb_info {
 112         u32 magic;
 113         int pipefd;
 114         struct file *pipe;
 115         struct pid *oz_pgrp;
 116         int catatonic;
 117         int version;
 118         int sub_version;
 119         int min_proto;
 120         int max_proto;
 121         unsigned long exp_timeout;
 122         unsigned int type;
 123         int reghost_enabled;
 124         int needs_reghost;
 125         struct super_block *sb;
 126         struct mutex wq_mutex;
 127         struct mutex pipe_mutex;
 128         spinlock_t fs_lock;
 129         struct autofs_wait_queue *queues; /* Wait queue pointer */
 130         spinlock_t lookup_lock;
 131         struct list_head active_list;
 132         struct list_head expiring_list;
 133         struct rcu_head rcu;
 134 };
 135
 136 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 137 {
 138         return (struct autofs_sb_info *)(sb->s_fs_info);
 139 }
 140
 141 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 142 {
 143         return (struct autofs_info *)(dentry->d_fsdata);
 144 }
 145
 146 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 147    processes which do manipulations for us in user space sees the raw
 148    filesystem without "magic".) */
 149
 150 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 151         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 152 }
 153
 154 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 155 void autofs4_free_ino(struct autofs_info *);
 156
 157 /* Expiration */
 158 int is_autofs4_dentry(struct dentry *);
 159 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 160 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 161                         struct autofs_sb_info *,
 162                         struct autofs_packet_expire __user *);
 163 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 164                             struct autofs_sb_info *sbi, int when);
 165 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 166                         struct autofs_sb_info *, int __user *);
 167 struct dentry *autofs4_expire_direct(struct super_block *sb,
 168                                      struct vfsmount *mnt,
 169                                      struct autofs_sb_info *sbi, int how);
 170 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 171                                        struct vfsmount *mnt,
 172                                        struct autofs_sb_info *sbi, int how);
 173
 174 /* Device node initialization */
 175
 176 int autofs_dev_ioctl_init(void);
 177 void autofs_dev_ioctl_exit(void);
 178
 179 /* Operations structures */
 180
 181 extern const struct inode_operations autofs4_symlink_inode_operations;
 182 extern const struct inode_operations autofs4_dir_inode_operations;
 183 extern const struct file_operations autofs4_dir_operations;
 184 extern const struct file_operations autofs4_root_operations;
 185 extern const struct dentry_operations autofs4_dentry_operations;
 186
 187 /* VFS automount flags management functions */
 188 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 189 {
 190         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 191 }
 192
 193 static inline void managed_dentry_set_managed(struct dentry *dentry)
 194 {
 195         spin_lock(&dentry->d_lock);
 196         __managed_dentry_set_managed(dentry);
 197         spin_unlock(&dentry->d_lock);
 198 }
 199
 200 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 201 {
 202         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 203 }
 204
 205 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 206 {
 207         spin_lock(&dentry->d_lock);
 208         __managed_dentry_clear_managed(dentry);
 209         spin_unlock(&dentry->d_lock);
 210 }
 211
 212 /* Initializing function */
 213
 214 int autofs4_fill_super(struct super_block *, void *, int);
 215 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 216 void autofs4_clean_ino(struct autofs_info *);
 217
 218 static inline int autofs_prepare_pipe(struct file *pipe)
 219 {
 220         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 221                 return -EINVAL;
 222         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 223                 return -EINVAL;
 224         /* We want a packet pipe */
 225         pipe->f_flags |= O_DIRECT;
 226         return 0;
 227 }
 228
 229 /* Queue management functions */
 230
 231 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 232 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 233 void autofs4_catatonic_mode(struct autofs_sb_info *);
 234
 235 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 236 {
 237         return new_encode_dev(sbi->sb->s_dev);
 238 }
 239
 240 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 241 {
 242         return d_inode(sbi->sb->s_root)->i_ino;
 243 }
 244
 245 static inline int simple_positive(struct dentry *dentry)
 246 {
 247         return d_really_is_positive(dentry) && !d_unhashed(dentry);
 248 }
 249
 250 static inline void __autofs4_add_expiring(struct dentry *dentry)
 251 {
 252         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 253         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 254         if (ino) {
 255                 if (list_empty(&ino->expiring))
 256                         list_add(&ino->expiring, &sbi->expiring_list);
 257         }
 258         return;
 259 }
 260
 261 static inline void autofs4_add_expiring(struct dentry *dentry)
 262 {
 263         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 264         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 265         if (ino) {
 266                 spin_lock(&sbi->lookup_lock);
 267                 if (list_empty(&ino->expiring))
 268                         list_add(&ino->expiring, &sbi->expiring_list);
 269                 spin_unlock(&sbi->lookup_lock);
 270         }
 271         return;
 272 }
 273
 274 static inline void autofs4_del_expiring(struct dentry *dentry)
 275 {
 276         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 277         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 278         if (ino) {
 279                 spin_lock(&sbi->lookup_lock);
 280                 if (!list_empty(&ino->expiring))
 281                         list_del_init(&ino->expiring);
 282                 spin_unlock(&sbi->lookup_lock);
 283         }
 284         return;
 285 }
 286
 287 extern void autofs4_kill_sb(struct super_block *);