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 /* 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. */
  49 struct autofs_info {
  50         struct dentry   *dentry;
  51         struct inode    *inode;
  52
  53         int             flags;
  54
  55         struct autofs_sb_info *sbi;
  56         unsigned long last_used;
  57         atomic_t count;
  58
  59         mode_t  mode;
  60         size_t  size;
  61
  62         void (*free)(struct autofs_info *);
  63         union {
  64                 const char *symlink;
  65         } u;
  66 };
  67
  68 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  69
  70 struct autofs_wait_queue {
  71         wait_queue_head_t queue;
  72         struct autofs_wait_queue *next;
  73         autofs_wqt_t wait_queue_token;
  74         /* We use the following to see what we are waiting for */
  75         unsigned int hash;
  76         unsigned int len;
  77         char *name;
  78         u32 dev;
  79         u64 ino;
  80         uid_t uid;
  81         gid_t gid;
  82         pid_t pid;
  83         pid_t tgid;
  84         /* This is for status reporting upon return */
  85         int status;
  86         atomic_t wait_ctr;
  87 };
  88
  89 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  90
  91 #define AUTOFS_TYPE_INDIRECT     0x0001
  92 #define AUTOFS_TYPE_DIRECT       0x0002
  93 #define AUTOFS_TYPE_OFFSET       0x0004
  94
  95 struct autofs_sb_info {
  96         u32 magic;
  97         int pipefd;
  98         struct file *pipe;
  99         pid_t oz_pgrp;
 100         int catatonic;
 101         int version;
 102         int sub_version;
 103         int min_proto;
 104         int max_proto;
 105         unsigned long exp_timeout;
 106         unsigned int type;
 107         int reghost_enabled;
 108         int needs_reghost;
 109         struct super_block *sb;
 110         struct mutex wq_mutex;
 111         spinlock_t fs_lock;
 112         struct autofs_wait_queue *queues; /* Wait queue pointer */
 113 };
 114
 115 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 116 {
 117         return (struct autofs_sb_info *)(sb->s_fs_info);
 118 }
 119
 120 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 121 {
 122         return (struct autofs_info *)(dentry->d_fsdata);
 123 }
 124
 125 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 126    processes which do manipulations for us in user space sees the raw
 127    filesystem without "magic".) */
 128
 129 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 130         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 131 }
 132
 133 /* Does a dentry have some pending activity? */
 134 static inline int autofs4_ispending(struct dentry *dentry)
 135 {
 136         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 137         int pending = 0;
 138
 139         if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
 140                 return 1;
 141
 142         if (inf) {
 143                 spin_lock(&inf->sbi->fs_lock);
 144                 pending = inf->flags & AUTOFS_INF_EXPIRING;
 145                 spin_unlock(&inf->sbi->fs_lock);
 146         }
 147
 148         return pending;
 149 }
 150
 151 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 152 {
 153         dst->f_path.dentry->d_inode->i_atime =
 154                 src->f_path.dentry->d_inode->i_atime;
 155         return;
 156 }
 157
 158 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 159 void autofs4_free_ino(struct autofs_info *);
 160
 161 /* Expiration */
 162 int is_autofs4_dentry(struct dentry *);
 163 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 164                         struct autofs_sb_info *,
 165                         struct autofs_packet_expire __user *);
 166 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 167                         struct autofs_sb_info *, int __user *);
 168
 169 /* Operations structures */
 170
 171 extern struct inode_operations autofs4_symlink_inode_operations;
 172 extern struct inode_operations autofs4_dir_inode_operations;
 173 extern struct inode_operations autofs4_root_inode_operations;
 174 extern struct inode_operations autofs4_indirect_root_inode_operations;
 175 extern struct inode_operations autofs4_direct_root_inode_operations;
 176 extern const struct file_operations autofs4_dir_operations;
 177 extern const struct file_operations autofs4_root_operations;
 178
 179 /* Initializing function */
 180
 181 int autofs4_fill_super(struct super_block *, void *, int);
 182 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 183
 184 /* Queue management functions */
 185
 186 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 187 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 188 void autofs4_catatonic_mode(struct autofs_sb_info *);
 189
 190 static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)
 191 {
 192         int res = 0;
 193
 194         while (d_mountpoint(*dentry)) {
 195                 int followed = follow_down(mnt, dentry);
 196                 if (!followed)
 197                         break;
 198                 res = 1;
 199         }
 200         return res;
 201 }
 202
 203 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
 204 {
 205         return new_encode_dev(sbi->sb->s_dev);
 206 }
 207
 208 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
 209 {
 210         return sbi->sb->s_root->d_inode->i_ino;
 211 }
 212
 213 static inline int simple_positive(struct dentry *dentry)
 214 {
 215         return dentry->d_inode && !d_unhashed(dentry);
 216 }
 217
 218 static inline int __simple_empty(struct dentry *dentry)
 219 {
 220         struct dentry *child;
 221         int ret = 0;
 222
 223         list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
 224                 if (simple_positive(child))
 225                         goto out;
 226         ret = 1;
 227 out:
 228         return ret;
 229 }
 230
 231 void autofs4_dentry_release(struct dentry *);
 232 extern void autofs4_kill_sb(struct super_block *);