fs/autofs4/autofs_i.h

   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 #define AUTOFS_SUPER_MAGIC 0x0187
  44
  45 /* Unified info structure.  This is pointed to by both the dentry and
  46    inode structures.  Each file in the filesystem has an instance of this
  47    structure.  It holds a reference to the dentry, so dentries are never
  48    flushed while the file exists.  All name lookups are dealt with at the
  49    dentry level, although the filesystem can interfere in the validation
  50    process.  Readdir is implemented by traversing the dentry lists. */
  51 struct autofs_info {
  52         struct dentry   *dentry;
  53         struct inode    *inode;
  54
  55         int             flags;
  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
  72 struct 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
  97 struct autofs_sb_info {
  98         u32 magic;
  99         struct dentry *root;
 100         int pipefd;
 101         struct file *pipe;
 102         pid_t 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         spinlock_t fs_lock;
 115         struct autofs_wait_queue *queues; /* Wait queue pointer */
 116 };
 117
 118 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 119 {
 120         return (struct autofs_sb_info *)(sb->s_fs_info);
 121 }
 122
 123 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 124 {
 125         return (struct autofs_info *)(dentry->d_fsdata);
 126 }
 127
 128 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 129    processes which do manipulations for us in user space sees the raw
 130    filesystem without "magic".) */
 131
 132 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 133         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 134 }
 135
 136 /* Does a dentry have some pending activity? */
 137 static inline int autofs4_ispending(struct dentry *dentry)
 138 {
 139         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 140         int pending = 0;
 141
 142         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 143                 return 1;
 144
 145         if (inf) {
 146                 spin_lock(&inf->sbi->fs_lock);
 147                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 148                 spin_unlock(&inf->sbi->fs_lock);
 149         }
 150
 151         return pending;
 152 }
 153
 154 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 155 {
 156         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 157         return;
 158 }
 159
 160 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 161 void autofs4_free_ino(struct autofs_info *);
 162
 163 /* Expiration */
 164 int is_autofs4_dentry(struct dentry *);
 165 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 166                         struct autofs_sb_info *,
 167                         struct autofs_packet_expire __user *);
 168 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 169                         struct autofs_sb_info *, int __user *);
 170
 171 /* Operations structures */
 172
 173 extern struct inode_operations autofs4_symlink_inode_operations;
 174 extern struct inode_operations autofs4_dir_inode_operations;
 175 extern struct inode_operations autofs4_root_inode_operations;
 176 extern struct inode_operations autofs4_indirect_root_inode_operations;
 177 extern struct inode_operations autofs4_direct_root_inode_operations;
 178 extern const struct file_operations autofs4_dir_operations;
 179 extern const struct file_operations autofs4_root_operations;
 180
 181 /* Initializing function */
 182
 183 int autofs4_fill_super(struct super_block *, void *, int);
 184 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 185
 186 /* Queue management functions */
 187
 188 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 189 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 190 void autofs4_catatonic_mode(struct autofs_sb_info *);
 191
 192 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 193 {
 194         int res = 0;
 195
 196         while (d_mountpoint(*dentry)) {
 197                 int followed = follow_down(mnt, dentry);
 198                 if (!followed)
 199                         break;
 200                 res = 1;
 201         }
 202         return res;
 203 }
 204
 205 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 206 {
 207         return new_encode_dev(sbi->sb->s_dev);
 208 }
 209
 210 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 211 {
 212         return sbi->sb->s_root->d_inode->i_ino;
 213 }
 214
 215 static inline int simple_positive(struct dentry *dentry)
 216 {
 217         return dentry->d_inode && !d_unhashed(dentry);
 218 }
 219
 220 static inline int __simple_empty(struct dentry *dentry)
 221 {
 222         struct dentry *child;
 223         int ret = 0;
 224
 225         list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 226                 if (simple_positive(child))
 227                         goto out;
 228         ret = 1;
 229 out:
 230         return ret;
 231 }
 232
 233 void autofs4_dentry_release(struct dentry *);
 234