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_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         int reghost_enabled;
 115         int needs_reghost;
 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 *autofs4_sbi(struct super_block *sb)
 128 {
 129         return (struct autofs_sb_info *)(sb->s_fs_info);
 130 }
 131
 132 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 133 {
 134         return (struct autofs_info *)(dentry->d_fsdata);
 135 }
 136
 137 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 138  * processes which do manipulations for us in user space sees the raw
 139  * filesystem without "magic".)
 140  */
 141 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
 142 {
 143         return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 144 }
 145
 146 struct inode *autofs4_get_inode(struct super_block *, umode_t);
 147 void autofs4_free_ino(struct autofs_info *);
 148
 149 /* Expiration */
 150 int is_autofs4_dentry(struct dentry *);
 151 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 152 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 153                        struct autofs_sb_info *,
 154                        struct autofs_packet_expire __user *);
 155 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 156                             struct autofs_sb_info *sbi, int when);
 157 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 158                          struct autofs_sb_info *, int __user *);
 159 struct dentry *autofs4_expire_direct(struct super_block *sb,
 160                                      struct vfsmount *mnt,
 161                                      struct autofs_sb_info *sbi, int how);
 162 struct dentry *autofs4_expire_indirect(struct super_block *sb,
 163                                        struct vfsmount *mnt,
 164                                        struct autofs_sb_info *sbi, int how);
 165
 166 /* Device node initialization */
 167
 168 int autofs_dev_ioctl_init(void);
 169 void autofs_dev_ioctl_exit(void);
 170
 171 /* Operations structures */
 172
 173 extern const struct inode_operations autofs4_symlink_inode_operations;
 174 extern const struct inode_operations autofs4_dir_inode_operations;
 175 extern const struct file_operations autofs4_dir_operations;
 176 extern const struct file_operations autofs4_root_operations;
 177 extern const struct dentry_operations autofs4_dentry_operations;
 178
 179 /* VFS automount flags management functions */
 180 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 181 {
 182         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 183 }
 184
 185 static inline void managed_dentry_set_managed(struct dentry *dentry)
 186 {
 187         spin_lock(&dentry->d_lock);
 188         __managed_dentry_set_managed(dentry);
 189         spin_unlock(&dentry->d_lock);
 190 }
 191
 192 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 193 {
 194         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 195 }
 196
 197 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 198 {
 199         spin_lock(&dentry->d_lock);
 200         __managed_dentry_clear_managed(dentry);
 201         spin_unlock(&dentry->d_lock);
 202 }
 203
 204 /* Initializing function */
 205
 206 int autofs4_fill_super(struct super_block *, void *, int);
 207 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 208 void autofs4_clean_ino(struct autofs_info *);
 209
 210 static inline int autofs_prepare_pipe(struct file *pipe)
 211 {
 212         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 213                 return -EINVAL;
 214         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 215                 return -EINVAL;
 216         /* We want a packet pipe */
 217         pipe->f_flags |= O_DIRECT;
 218         return 0;
 219 }
 220
 221 /* Queue management functions */
 222
 223 int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
 224 int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 225 void autofs4_catatonic_mode(struct autofs_sb_info *);
 226
 227 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 228 {
 229         return new_encode_dev(sbi->sb->s_dev);
 230 }
 231
 232 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 233 {
 234         return d_inode(sbi->sb->s_root)->i_ino;
 235 }
 236
 237 static inline void __autofs4_add_expiring(struct dentry *dentry)
 238 {
 239         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 240         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 241
 242         if (ino) {
 243                 if (list_empty(&ino->expiring))
 244                         list_add(&ino->expiring, &sbi->expiring_list);
 245         }
 246 }
 247
 248 static inline void autofs4_add_expiring(struct dentry *dentry)
 249 {
 250         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 251         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 252
 253         if (ino) {
 254                 spin_lock(&sbi->lookup_lock);
 255                 if (list_empty(&ino->expiring))
 256                         list_add(&ino->expiring, &sbi->expiring_list);
 257                 spin_unlock(&sbi->lookup_lock);
 258         }
 259 }
 260
 261 static inline void autofs4_del_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
 266         if (ino) {
 267                 spin_lock(&sbi->lookup_lock);
 268                 if (!list_empty(&ino->expiring))
 269                         list_del_init(&ino->expiring);
 270                 spin_unlock(&sbi->lookup_lock);
 271         }
 272 }
 273
 274 extern void autofs4_kill_sb(struct super_block *);