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 #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_NO_RCU       (1<<1) /* the dentry is being considered
  74                                         * for expiry, so RCU_walk is
  75                                         * not permitted
  76                                         */
  77 #define AUTOFS_INF_PENDING      (1<<2) /* dentry pending mount */
  78
  79 struct autofs_wait_queue {
  80         wait_queue_head_t queue;
  81         struct autofs_wait_queue *next;
  82         autofs_wqt_t wait_queue_token;
  83         /* We use the following to see what we are waiting for */
  84         struct qstr name;
  85         u32 dev;
  86         u64 ino;
  87         kuid_t uid;
  88         kgid_t gid;
  89         pid_t pid;
  90         pid_t tgid;
  91         /* This is for status reporting upon return */
  92         int status;
  93         unsigned int wait_ctr;
  94 };
  95
  96 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  97
  98 struct autofs_sb_info {
  99         u32 magic;
 100         int pipefd;
 101         struct file *pipe;
 102         struct pid *oz_pgrp;
 103         int catatonic;
 104         int version;
 105         int sub_version;
 106         int min_proto;
 107         int max_proto;
 108         unsigned long exp_timeout;
 109         unsigned int type;
 110         int reghost_enabled;
 111         int needs_reghost;
 112         struct super_block *sb;
 113         struct mutex wq_mutex;
 114         struct mutex pipe_mutex;
 115         spinlock_t fs_lock;
 116         struct autofs_wait_queue *queues; /* Wait queue pointer */
 117         spinlock_t lookup_lock;
 118         struct list_head active_list;
 119         struct list_head expiring_list;
 120         struct rcu_head rcu;
 121 };
 122
 123 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 124 {
 125         return (struct autofs_sb_info *)(sb->s_fs_info);
 126 }
 127
 128 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 129 {
 130         return (struct autofs_info *)(dentry->d_fsdata);
 131 }
 132
 133 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 134  * processes which do manipulations for us in user space sees the raw
 135  * filesystem without "magic".)
 136  */
 137 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
 138 {
 139         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 140 }
 141
 142 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 143 void autofs4_free_ino(struct autofs_info *);
 144
 145 /* Expiration */
 146 int is_autofs4_dentry(struct dentry *);
 147 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 148 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 149                        struct autofs_sb_info *,
 150                        struct autofs_packet_expire __user *);
 151 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 152                             struct autofs_sb_info *sbi, int when);
 153 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 154                          struct autofs_sb_info *, int __user *);
 155 struct dentry *autofs4_expire_direct(struct super_block *sb,
 156                                      struct vfsmount *mnt,
 157                                      struct autofs_sb_info *sbi, int how);
 158 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 159                                        struct vfsmount *mnt,
 160                                        struct autofs_sb_info *sbi, int how);
 161
 162 /* Device node initialization */
 163
 164 int autofs_dev_ioctl_init(void);
 165 void autofs_dev_ioctl_exit(void);
 166
 167 /* Operations structures */
 168
 169 extern const struct inode_operations autofs4_symlink_inode_operations;
 170 extern const struct inode_operations autofs4_dir_inode_operations;
 171 extern const struct file_operations autofs4_dir_operations;
 172 extern const struct file_operations autofs4_root_operations;
 173 extern const struct dentry_operations autofs4_dentry_operations;
 174
 175 /* VFS automount flags management functions */
 176 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 177 {
 178         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 179 }
 180
 181 static inline void managed_dentry_set_managed(struct dentry *dentry)
 182 {
 183         spin_lock(&dentry->d_lock);
 184         __managed_dentry_set_managed(dentry);
 185         spin_unlock(&dentry->d_lock);
 186 }
 187
 188 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 189 {
 190         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 191 }
 192
 193 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 194 {
 195         spin_lock(&dentry->d_lock);
 196         __managed_dentry_clear_managed(dentry);
 197         spin_unlock(&dentry->d_lock);
 198 }
 199
 200 /* Initializing function */
 201
 202 int autofs4_fill_super(struct super_block *, void *, int);
 203 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 204 void autofs4_clean_ino(struct autofs_info *);
 205
 206 static inline int autofs_prepare_pipe(struct file *pipe)
 207 {
 208         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 209                 return -EINVAL;
 210         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 211                 return -EINVAL;
 212         /* We want a packet pipe */
 213         pipe->f_flags |= O_DIRECT;
 214         return 0;
 215 }
 216
 217 /* Queue management functions */
 218
 219 int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
 220 int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 221 void autofs4_catatonic_mode(struct autofs_sb_info *);
 222
 223 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 224 {
 225         return new_encode_dev(sbi->sb->s_dev);
 226 }
 227
 228 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 229 {
 230         return d_inode(sbi->sb->s_root)->i_ino;
 231 }
 232
 233 static inline void __autofs4_add_expiring(struct dentry *dentry)
 234 {
 235         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 236         struct autofs_info *ino = autofs4_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 autofs4_add_expiring(struct dentry *dentry)
 245 {
 246         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 247         struct autofs_info *ino = autofs4_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 autofs4_del_expiring(struct dentry *dentry)
 258 {
 259         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 260         struct autofs_info *ino = autofs4_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 extern void autofs4_kill_sb(struct super_block *);