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