LXR linux/fs/autofs4/autofs

   1/* -*- c -*- ------------------------------------------------------------- *
   2 *   
   3 * linux/fs/autofs/autofs_i.h
   4 *
   5 *   Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
   6 *   Copyright 2005-2006 Ian Kent <raven@themaw.net>
   7 *
   8 * This file is part of the Linux kernel and is made available under
   9 * the terms of the GNU General Public License, version 2, or at your
  10 * option, any later version, incorporated herein by reference.
  11 *
  12 * ----------------------------------------------------------------------- */
  13
  14/* Internal header file for autofs */
  15
  16#include <linux/auto_fs4.h>
  17#include <linux/mutex.h>
  18#include <linux/list.h>
  19
  20/* This is the range of ioctl() numbers we claim as ours */
  21#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  22#define AUTOFS_IOC_COUNT     32
  23
  24#include <linux/kernel.h>
  25#include <linux/slab.h>
  26#include <linux/time.h>
  27#include <linux/string.h>
  28#include <linux/wait.h>
  29#include <linux/sched.h>
  30#include <linux/mount.h>
  31#include <linux/namei.h>
  32#include <asm/current.h>
  33#include <asm/uaccess.h>
  34
  35/* #define DEBUG */
  36
  37#ifdef DEBUG
  38#define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
  39#else
  40#define DPRINTK(fmt,args...) do {} while(0)
  41#endif
  42
  43/* Unified info structure.  This is pointed to by both the dentry and
  44   inode structures.  Each file in the filesystem has an instance of this
  45   structure.  It holds a reference to the dentry, so dentries are never
  46   flushed while the file exists.  All name lookups are dealt with at the
  47   dentry level, although the filesystem can interfere in the validation
  48   process.  Readdir is implemented by traversing the dentry lists. */
  49struct autofs_info {
  50        struct dentry   *dentry;
  51        struct inode    *inode;
  52
  53        int             flags;
  54
  55        struct list_head rehash;
  56
  57        struct autofs_sb_info *sbi;
  58        unsigned long last_used;
  59        atomic_t count;
  60
  61        mode_t  mode;
  62        size_t  size;
  63
  64        void (*free)(struct autofs_info *);
  65        union {
  66                const char *symlink;
  67        } u;
  68};
  69
  70#define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  71
  72struct autofs_wait_queue {
  73        wait_queue_head_t queue;
  74        struct autofs_wait_queue *next;
  75        autofs_wqt_t wait_queue_token;
  76        /* We use the following to see what we are waiting for */
  77        unsigned int hash;
  78        unsigned int len;
  79        char *name;
  80        u32 dev;
  81        u64 ino;
  82        uid_t uid;
  83        gid_t gid;
  84        pid_t pid;
  85        pid_t tgid;
  86        /* This is for status reporting upon return */
  87        int status;
  88        atomic_t wait_ctr;
  89};
  90
  91#define AUTOFS_SBI_MAGIC 0x6d4a556d
  92
  93#define AUTOFS_TYPE_INDIRECT     0x0001
  94#define AUTOFS_TYPE_DIRECT       0x0002
  95#define AUTOFS_TYPE_OFFSET       0x0004
  96
  97struct autofs_sb_info {
  98        u32 magic;
  99        int pipefd;
 100        struct file *pipe;
 101        pid_t oz_pgrp;
 102        int catatonic;
 103        int version;
 104        int sub_version;
 105        int min_proto;
 106        int max_proto;
 107        unsigned long exp_timeout;
 108        unsigned int type;
 109        int reghost_enabled;
 110        int needs_reghost;
 111        struct super_block *sb;
 112        struct mutex wq_mutex;
 113        spinlock_t fs_lock;
 114        struct autofs_wait_queue *queues; /* Wait queue pointer */
 115        spinlock_t rehash_lock;
 116        struct list_head rehash_list;
 117};
 118
 119static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 120{
 121        return (struct autofs_sb_info *)(sb->s_fs_info);
 122}
 123
 124static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 125{
 126        return (struct autofs_info *)(dentry->d_fsdata);
 127}
 128
 129/* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 130   processes which do manipulations for us in user space sees the raw
 131   filesystem without "magic".) */
 132
 133static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 134        return sbi->catatonic || task_pgrp_nr(current) == sbi->oz_pgrp;
 135}
 136
 137/* Does a dentry have some pending activity? */
 138static inline int autofs4_ispending(struct dentry *dentry)
 139{
 140        struct autofs_info *inf = autofs4_dentry_ino(dentry);
 141        int pending = 0;
 142
 143        if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 144                return 1;
 145
 146        if (inf) {
 147                spin_lock(&inf->sbi->fs_lock);
 148                pending = inf->flags & AUTOFS_INF_EXPIRING;
 149                spin_unlock(&inf->sbi->fs_lock);
 150        }
 151
 152        return pending;
 153}
 154
 155static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 156{
 157        dst->f_path.dentry->d_inode->i_atime =
 158                src->f_path.dentry->d_inode->i_atime;
 159        return;
 160}
 161
 162struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 163void autofs4_free_ino(struct autofs_info *);
 164
 165/* Expiration */
 166int is_autofs4_dentry(struct dentry *);
 167int autofs4_expire_run(struct super_block *, struct vfsmount *,
 168                        struct autofs_sb_info *,
 169                        struct autofs_packet_expire __user *);
 170int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 171                        struct autofs_sb_info *, int __user *);
 172
 173/* Operations structures */
 174
 175extern const struct inode_operations autofs4_symlink_inode_operations;
 176extern const struct inode_operations autofs4_dir_inode_operations;
 177extern const struct inode_operations autofs4_root_inode_operations;
 178extern const struct inode_operations autofs4_indirect_root_inode_operations;
 179extern const struct inode_operations autofs4_direct_root_inode_operations;
 180extern const struct file_operations autofs4_dir_operations;
 181extern const struct file_operations autofs4_root_operations;
 182
 183/* Initializing function */
 184
 185int autofs4_fill_super(struct super_block *, void *, int);
 186struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 187
 188/* Queue management functions */
 189
 190int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 191int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 192void autofs4_catatonic_mode(struct autofs_sb_info *);
 193
 194static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 195{
 196        int res = 0;
 197
 198        while (d_mountpoint(*dentry)) {
 199                int followed = follow_down(mnt, dentry);
 200                if (!followed)
 201                        break;
 202                res = 1;
 203        }
 204        return res;
 205}
 206
 207static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 208{
 209        return new_encode_dev(sbi->sb->s_dev);
 210}
 211
 212static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 213{
 214        return sbi->sb->s_root->d_inode->i_ino;
 215}
 216
 217static inline int simple_positive(struct dentry *dentry)
 218{
 219        return dentry->d_inode && !d_unhashed(dentry);
 220}
 221
 222static inline int __simple_empty(struct dentry *dentry)
 223{
 224        struct dentry *child;
 225        int ret = 0;
 226
 227        list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 228                if (simple_positive(child))
 229                        goto out;
 230        ret = 1;
 231out:
 232        return ret;
 233}
 234
 235void autofs4_dentry_release(struct dentry *);
 236extern void autofs4_kill_sb(struct super_block *);
 237