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#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 */
  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_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
  79struct 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
  98struct 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
 123static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 124{
 125        return (struct autofs_sb_info *)(sb->s_fs_info);
 126}
 127
 128static 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 */
 137static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
 138{
 139        return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 140}
 141
 142struct inode *autofs4_get_inode(struct super_block *, umode_t);
 143void autofs4_free_ino(struct autofs_info *);
 144
 145/* Expiration */
 146int is_autofs4_dentry(struct dentry *);
 147int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
 148int autofs4_expire_run(struct super_block *, struct vfsmount *,
 149                       struct autofs_sb_info *,
 150                       struct autofs_packet_expire __user *);
 151int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 152                            struct autofs_sb_info *sbi, int when);
 153int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 154                         struct autofs_sb_info *, int __user *);
 155struct dentry *autofs4_expire_direct(struct super_block *sb,
 156                                     struct vfsmount *mnt,
 157                                     struct autofs_sb_info *sbi, int how);
 158struct 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
 164int autofs_dev_ioctl_init(void);
 165void autofs_dev_ioctl_exit(void);
 166
 167/* Operations structures */
 168
 169extern const struct inode_operations autofs4_symlink_inode_operations;
 170extern const struct inode_operations autofs4_dir_inode_operations;
 171extern const struct file_operations autofs4_dir_operations;
 172extern const struct file_operations autofs4_root_operations;
 173extern const struct dentry_operations autofs4_dentry_operations;
 174
 175/* VFS automount flags management functions */
 176static inline void __managed_dentry_set_managed(struct dentry *dentry)
 177{
 178        dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 179}
 180
 181static 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
 188static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 189{
 190        dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 191}
 192
 193static 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
 202int autofs4_fill_super(struct super_block *, void *, int);
 203struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
 204void autofs4_clean_ino(struct autofs_info *);
 205
 206static 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
 219int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
 220int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 221void autofs4_catatonic_mode(struct autofs_sb_info *);
 222
 223static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 224{
 225        return new_encode_dev(sbi->sb->s_dev);
 226}
 227
 228static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 229{
 230        return d_inode(sbi->sb->s_root)->i_ino;
 231}
 232
 233static 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
 244static 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
 257static 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
 270extern void autofs4_kill_sb(struct super_block *);
 271