fs/autofs4/autofs_i.h

   1 /*
   2  *  Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
   3  *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
   4  *
   5  * This file is part of the Linux kernel and is made available under
   6  * the terms of the GNU General Public License, version 2, or at your
   7  * option, any later version, incorporated herein by reference.
   8  */
   9
  10 /* Internal header file for autofs */
  11
  12 #include <linux/auto_fs4.h>
  13 #include <linux/auto_dev-ioctl.h>
  14 #include <linux/mutex.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/list.h>
  17
  18 /* This is the range of ioctl() numbers we claim as ours */
  19 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  20 #define AUTOFS_IOC_COUNT     32
  21
  22 #define AUTOFS_DEV_IOCTL_IOC_FIRST      (AUTOFS_DEV_IOCTL_VERSION)
  23 #define AUTOFS_DEV_IOCTL_IOC_COUNT      (AUTOFS_IOC_COUNT - 11)
  24
  25 #include <linux/kernel.h>
  26 #include <linux/slab.h>
  27 #include <linux/time.h>
  28 #include <linux/string.h>
  29 #include <linux/wait.h>
  30 #include <linux/sched.h>
  31 #include <linux/mount.h>
  32 #include <linux/namei.h>
  33 #include <asm/current.h>
  34 #include <linux/uaccess.h>
  35
  36 /* #define DEBUG */
  37
  38 #define DPRINTK(fmt, ...)                               \
  39         pr_debug(KBUILD_MODNAME ":pid:%d:%s: " fmt "\n",\
  40                 current->pid, __func__, ##__VA_ARGS__)
  41
  42 #define AUTOFS_WARN(fmt, ...)                           \
  43         pr_warn(KBUILD_MODNAME ":pid:%d:%s: " fmt "\n", \
  44                 current->pid, __func__, ##__VA_ARGS__)
  45
  46 #define AUTOFS_ERROR(fmt, ...)                          \
  47         pr_err(KBUILD_MODNAME ":pid:%d:%s: " fmt "\n",  \
  48                 current->pid, __func__, ##__VA_ARGS__)
  49
  50 /*
  51  * Unified info structure.  This is pointed to by both the dentry and
  52  * inode structures.  Each file in the filesystem has an instance of this
  53  * structure.  It holds a reference to the dentry, so dentries are never
  54  * flushed while the file exists.  All name lookups are dealt with at the
  55  * dentry level, although the filesystem can interfere in the validation
  56  * process.  Readdir is implemented by traversing the dentry lists.
  57  */
  58 struct autofs_info {
  59         struct dentry   *dentry;
  60         struct inode    *inode;
  61
  62         int             flags;
  63
  64         struct completion expire_complete;
  65
  66         struct list_head active;
  67         int active_count;
  68
  69         struct list_head expiring;
  70
  71         struct autofs_sb_info *sbi;
  72         unsigned long last_used;
  73         atomic_t count;
  74
  75         kuid_t uid;
  76         kgid_t gid;
  77 };
  78
  79 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry in the process of expiring */
  80 #define AUTOFS_INF_NO_RCU       (1<<1) /* the dentry is being considered
  81                                         * for expiry, so RCU_walk is
  82                                         * not permitted
  83                                         */
  84 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  85
  86 struct autofs_wait_queue {
  87         wait_queue_head_t queue;
  88         struct autofs_wait_queue *next;
  89         autofs_wqt_t wait_queue_token;
  90         /* We use the following to see what we are waiting for */
  91         struct qstr name;
  92         u32 dev;
  93         u64 ino;
  94         kuid_t uid;
  95         kgid_t gid;
  96         pid_t pid;
  97         pid_t tgid;
  98         /* This is for status reporting upon return */
  99         int status;
 100         unsigned int wait_ctr;
 101 };
 102
 103 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 104
 105 struct autofs_sb_info {
 106         u32 magic;
 107         int pipefd;
 108         struct file *pipe;
 109         struct pid *oz_pgrp;
 110         int catatonic;
 111         int version;
 112         int sub_version;
 113         int min_proto;
 114         int max_proto;
 115         unsigned long exp_timeout;
 116         unsigned int type;
 117         int reghost_enabled;
 118         int needs_reghost;
 119         struct super_block *sb;
 120         struct mutex wq_mutex;
 121         struct mutex pipe_mutex;
 122         spinlock_t fs_lock;
 123         struct autofs_wait_queue *queues; /* Wait queue pointer */
 124         spinlock_t lookup_lock;
 125         struct list_head active_list;
 126         struct list_head expiring_list;
 127         struct rcu_head rcu;
 128 };
 129
 130 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 131 {
 132         return (struct autofs_sb_info *)(sb->s_fs_info);
 133 }
 134
 135 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 136 {
 137         return (struct autofs_info *)(dentry->d_fsdata);
 138 }
 139
 140 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 141  * processes which do manipulations for us in user space sees the raw
 142  * filesystem without "magic".)
 143  */
 144 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
 145 {
 146         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 147 }
 148
 149 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 150 void autofs4_free_ino(struct autofs_info *);
 151
 152 /* Expiration */
 153 int is_autofs4_dentry(struct dentry *);
 154 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 155 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 156                        struct autofs_sb_info *,
 157                        struct autofs_packet_expire __user *);
 158 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 159                             struct autofs_sb_info *sbi, int when);
 160 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 161                          struct autofs_sb_info *, int __user *);
 162 struct dentry *autofs4_expire_direct(struct super_block *sb,
 163                                      struct vfsmount *mnt,
 164                                      struct autofs_sb_info *sbi, int how);
 165 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 166                                        struct vfsmount *mnt,
 167                                        struct autofs_sb_info *sbi, int how);
 168
 169 /* Device node initialization */
 170
 171 int autofs_dev_ioctl_init(void);
 172 void autofs_dev_ioctl_exit(void);
 173
 174 /* Operations structures */
 175
 176 extern const struct inode_operations autofs4_symlink_inode_operations;
 177 extern const struct inode_operations autofs4_dir_inode_operations;
 178 extern const struct file_operations autofs4_dir_operations;
 179 extern const struct file_operations autofs4_root_operations;
 180 extern const struct dentry_operations autofs4_dentry_operations;
 181
 182 /* VFS automount flags management functions */
 183 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 184 {
 185         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 186 }
 187
 188 static inline void managed_dentry_set_managed(struct dentry *dentry)
 189 {
 190         spin_lock(&dentry->d_lock);
 191         __managed_dentry_set_managed(dentry);
 192         spin_unlock(&dentry->d_lock);
 193 }
 194
 195 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 196 {
 197         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 198 }
 199
 200 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 201 {
 202         spin_lock(&dentry->d_lock);
 203         __managed_dentry_clear_managed(dentry);
 204         spin_unlock(&dentry->d_lock);
 205 }
 206
 207 /* Initializing function */
 208
 209 int autofs4_fill_super(struct super_block *, void *, int);
 210 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 211 void autofs4_clean_ino(struct autofs_info *);
 212
 213 static inline int autofs_prepare_pipe(struct file *pipe)
 214 {
 215         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 216                 return -EINVAL;
 217         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 218                 return -EINVAL;
 219         /* We want a packet pipe */
 220         pipe->f_flags |= O_DIRECT;
 221         return 0;
 222 }
 223
 224 /* Queue management functions */
 225
 226 int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
 227 int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 228 void autofs4_catatonic_mode(struct autofs_sb_info *);
 229
 230 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 231 {
 232         return new_encode_dev(sbi->sb->s_dev);
 233 }
 234
 235 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 236 {
 237         return d_inode(sbi->sb->s_root)->i_ino;
 238 }
 239
 240 static inline void __autofs4_add_expiring(struct dentry *dentry)
 241 {
 242         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 243         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 244
 245         if (ino) {
 246                 if (list_empty(&ino->expiring))
 247                         list_add(&ino->expiring, &sbi->expiring_list);
 248         }
 249 }
 250
 251 static inline void autofs4_add_expiring(struct dentry *dentry)
 252 {
 253         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 254         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 255
 256         if (ino) {
 257                 spin_lock(&sbi->lookup_lock);
 258                 if (list_empty(&ino->expiring))
 259                         list_add(&ino->expiring, &sbi->expiring_list);
 260                 spin_unlock(&sbi->lookup_lock);
 261         }
 262 }
 263
 264 static inline void autofs4_del_expiring(struct dentry *dentry)
 265 {
 266         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 267         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 268
 269         if (ino) {
 270                 spin_lock(&sbi->lookup_lock);
 271                 if (!list_empty(&ino->expiring))
 272                         list_del_init(&ino->expiring);
 273                 spin_unlock(&sbi->lookup_lock);
 274         }
 275 }
 276
 277 extern void autofs4_kill_sb(struct super_block *);