fs/autofs/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_fs.h>
  13 #include <linux/auto_dev-ioctl.h>
  14
  15 #include <linux/kernel.h>
  16 #include <linux/slab.h>
  17 #include <linux/time.h>
  18 #include <linux/string.h>
  19 #include <linux/wait.h>
  20 #include <linux/sched.h>
  21 #include <linux/sched/signal.h>
  22 #include <linux/mount.h>
  23 #include <linux/namei.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/mutex.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/list.h>
  28 #include <linux/completion.h>
  29 #include <linux/file.h>
  30 #include <linux/magic.h>
  31
  32 /* This is the range of ioctl() numbers we claim as ours */
  33 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  34 #define AUTOFS_IOC_COUNT     32
  35
  36 #define AUTOFS_DEV_IOCTL_IOC_FIRST      (AUTOFS_DEV_IOCTL_VERSION)
  37 #define AUTOFS_DEV_IOCTL_IOC_COUNT \
  38         (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
  39
  40 #ifdef pr_fmt
  41 #undef pr_fmt
  42 #endif
  43 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
  44
  45 /*
  46  * Unified info structure.  This is pointed to by both the dentry and
  47  * inode structures.  Each file in the filesystem has an instance of this
  48  * structure.  It holds a reference to the dentry, so dentries are never
  49  * flushed while the file exists.  All name lookups are dealt with at the
  50  * dentry level, although the filesystem can interfere in the validation
  51  * process.  Readdir is implemented by traversing the dentry lists.
  52  */
  53 struct autofs_info {
  54         struct dentry   *dentry;
  55         struct inode    *inode;
  56
  57         int             flags;
  58
  59         struct completion expire_complete;
  60
  61         struct list_head active;
  62         int active_count;
  63
  64         struct list_head expiring;
  65
  66         struct autofs_sb_info *sbi;
  67         unsigned long last_used;
  68         atomic_t count;
  69
  70         kuid_t uid;
  71         kgid_t gid;
  72 };
  73
  74 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry in the process of expiring */
  75 #define AUTOFS_INF_WANT_EXPIRE  (1<<1) /* the dentry is being considered
  76                                         * for expiry, so RCU_walk is
  77                                         * not permitted.  If it progresses to
  78                                         * actual expiry attempt, the flag is
  79                                         * not cleared when EXPIRING is set -
  80                                         * in that case it gets cleared only
  81                                         * when it comes to clearing EXPIRING.
  82                                         */
  83 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  84
  85 struct autofs_wait_queue {
  86         wait_queue_head_t queue;
  87         struct autofs_wait_queue *next;
  88         autofs_wqt_t wait_queue_token;
  89         /* We use the following to see what we are waiting for */
  90         struct qstr name;
  91         u32 dev;
  92         u64 ino;
  93         kuid_t uid;
  94         kgid_t gid;
  95         pid_t pid;
  96         pid_t tgid;
  97         /* This is for status reporting upon return */
  98         int status;
  99         unsigned int wait_ctr;
 100 };
 101
 102 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 103
 104 struct autofs_sb_info {
 105         u32 magic;
 106         int pipefd;
 107         struct file *pipe;
 108         struct pid *oz_pgrp;
 109         int catatonic;
 110         int version;
 111         int sub_version;
 112         int min_proto;
 113         int max_proto;
 114         unsigned long exp_timeout;
 115         unsigned int type;
 116         struct super_block *sb;
 117         struct mutex wq_mutex;
 118         struct mutex pipe_mutex;
 119         spinlock_t fs_lock;
 120         struct autofs_wait_queue *queues; /* Wait queue pointer */
 121         spinlock_t lookup_lock;
 122         struct list_head active_list;
 123         struct list_head expiring_list;
 124         struct rcu_head rcu;
 125 };
 126
 127 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 128 {
 129         return sb->s_magic != AUTOFS_SUPER_MAGIC ?
 130                 NULL : (struct autofs_sb_info *)(sb->s_fs_info);
 131 }
 132
 133 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
 134 {
 135         return (struct autofs_info *)(dentry->d_fsdata);
 136 }
 137
 138 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
 139  * processes which do manipulations for us in user space sees the raw
 140  * filesystem without "magic".)
 141  */
 142 static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
 143 {
 144         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 145 }
 146
 147 struct inode *autofs_get_inode(struct super_block *, umode_t);
 148 void autofs_free_ino(struct autofs_info *);
 149
 150 /* Expiration */
 151 int is_autofs_dentry(struct dentry *);
 152 int autofs_expire_wait(const struct path *path, int rcu_walk);
 153 int autofs_expire_run(struct super_block *, struct vfsmount *,
 154                       struct autofs_sb_info *,
 155                       struct autofs_packet_expire __user *);
 156 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 157                            struct autofs_sb_info *sbi, unsigned int how);
 158 int autofs_expire_multi(struct super_block *, struct vfsmount *,
 159                         struct autofs_sb_info *, int __user *);
 160
 161 /* Device node initialization */
 162
 163 int autofs_dev_ioctl_init(void);
 164 void autofs_dev_ioctl_exit(void);
 165
 166 /* Operations structures */
 167
 168 extern const struct inode_operations autofs_symlink_inode_operations;
 169 extern const struct inode_operations autofs_dir_inode_operations;
 170 extern const struct file_operations autofs_dir_operations;
 171 extern const struct file_operations autofs_root_operations;
 172 extern const struct dentry_operations autofs_dentry_operations;
 173
 174 /* VFS automount flags management functions */
 175 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 176 {
 177         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 178 }
 179
 180 static inline void managed_dentry_set_managed(struct dentry *dentry)
 181 {
 182         spin_lock(&dentry->d_lock);
 183         __managed_dentry_set_managed(dentry);
 184         spin_unlock(&dentry->d_lock);
 185 }
 186
 187 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 188 {
 189         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 190 }
 191
 192 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 193 {
 194         spin_lock(&dentry->d_lock);
 195         __managed_dentry_clear_managed(dentry);
 196         spin_unlock(&dentry->d_lock);
 197 }
 198
 199 /* Initializing function */
 200
 201 int autofs_fill_super(struct super_block *, void *, int);
 202 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
 203 void autofs_clean_ino(struct autofs_info *);
 204
 205 static inline int autofs_prepare_pipe(struct file *pipe)
 206 {
 207         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 208                 return -EINVAL;
 209         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 210                 return -EINVAL;
 211         /* We want a packet pipe */
 212         pipe->f_flags |= O_DIRECT;
 213         return 0;
 214 }
 215
 216 /* Queue management functions */
 217
 218 int autofs_wait(struct autofs_sb_info *,
 219                  const struct path *, enum autofs_notify);
 220 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 221 void autofs_catatonic_mode(struct autofs_sb_info *);
 222
 223 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
 224 {
 225         return new_encode_dev(sbi->sb->s_dev);
 226 }
 227
 228 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
 229 {
 230         return d_inode(sbi->sb->s_root)->i_ino;
 231 }
 232
 233 static inline void __autofs_add_expiring(struct dentry *dentry)
 234 {
 235         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 236         struct autofs_info *ino = autofs_dentry_ino(dentry);
 237
 238         if (ino) {
 239                 if (list_empty(&ino->expiring))
 240                         list_add(&ino->expiring, &sbi->expiring_list);
 241         }
 242 }
 243
 244 static inline void autofs_add_expiring(struct dentry *dentry)
 245 {
 246         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 247         struct autofs_info *ino = autofs_dentry_ino(dentry);
 248
 249         if (ino) {
 250                 spin_lock(&sbi->lookup_lock);
 251                 if (list_empty(&ino->expiring))
 252                         list_add(&ino->expiring, &sbi->expiring_list);
 253                 spin_unlock(&sbi->lookup_lock);
 254         }
 255 }
 256
 257 static inline void autofs_del_expiring(struct dentry *dentry)
 258 {
 259         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 260         struct autofs_info *ino = autofs_dentry_ino(dentry);
 261
 262         if (ino) {
 263                 spin_lock(&sbi->lookup_lock);
 264                 if (!list_empty(&ino->expiring))
 265                         list_del_init(&ino->expiring);
 266                 spin_unlock(&sbi->lookup_lock);
 267         }
 268 }
 269
 270 void autofs_kill_sb(struct super_block *);