LXR linux/fs/autofs4/autofs

   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 */
  51struct 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
  83struct 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
 102struct 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
 125static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 126{
 127        return (struct autofs_sb_info *)(sb->s_fs_info);
 128}
 129
 130static 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 */
 139static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
 140{
 141        return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 142}
 143
 144struct inode *autofs4_get_inode(struct super_block *, umode_t);
 145void autofs4_free_ino(struct autofs_info *);
 146
 147/* Expiration */
 148int is_autofs4_dentry(struct dentry *);
 149int autofs4_expire_wait(const struct path *path, int rcu_walk);
 150int autofs4_expire_run(struct super_block *, struct vfsmount *,
 151                       struct autofs_sb_info *,
 152                       struct autofs_packet_expire __user *);
 153int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 154                            struct autofs_sb_info *sbi, int when);
 155int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 156                         struct autofs_sb_info *, int __user *);
 157struct dentry *autofs4_expire_direct(struct super_block *sb,
 158                                     struct vfsmount *mnt,
 159                                     struct autofs_sb_info *sbi, int how);
 160struct 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
 166int autofs_dev_ioctl_init(void);
 167void autofs_dev_ioctl_exit(void);
 168
 169/* Operations structures */
 170
 171extern const struct inode_operations autofs4_symlink_inode_operations;
 172extern const struct inode_operations autofs4_dir_inode_operations;
 173extern const struct file_operations autofs4_dir_operations;
 174extern const struct file_operations autofs4_root_operations;
 175extern const struct dentry_operations autofs4_dentry_operations;
 176
 177/* VFS automount flags management functions */
 178static inline void __managed_dentry_set_managed(struct dentry *dentry)
 179{
 180        dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 181}
 182
 183static 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
 190static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 191{
 192        dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 193}
 194
 195static 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
 204int autofs4_fill_super(struct super_block *, void *, int);
 205struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 206void autofs4_clean_ino(struct autofs_info *);
 207
 208static 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
 221int autofs4_wait(struct autofs_sb_info *,
 222                 const struct path *, enum autofs_notify);
 223int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 224void autofs4_catatonic_mode(struct autofs_sb_info *);
 225
 226static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 227{
 228        return new_encode_dev(sbi->sb->s_dev);
 229}
 230
 231static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 232{
 233        return d_inode(sbi->sb->s_root)->i_ino;
 234}
 235
 236static 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
 247static 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
 260static 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
 273void autofs4_kill_sb(struct super_block *);
 274