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  *
   7  * This file is part of the Linux kernel and is made available under
   8  * the terms of the GNU General Public License, version 2, or at your
   9  * option, any later version, incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /* Internal header file for autofs */
  14
  15 #include <linux/auto_fs4.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 #include <linux/kernel.h>
  23 #include <linux/slab.h>
  24 #include <linux/time.h>
  25 #include <linux/string.h>
  26 #include <linux/wait.h>
  27 #include <linux/sched.h>
  28 #include <linux/mount.h>
  29 #include <linux/namei.h>
  30 #include <asm/current.h>
  31 #include <asm/uaccess.h>
  32
  33 /* #define DEBUG */
  34
  35 #ifdef DEBUG
  36 #define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
  37 #else
  38 #define DPRINTK(fmt,args...) do {} while(0)
  39 #endif
  40
  41 #define AUTOFS_SUPER_MAGIC 0x0187
  42
  43 /*
  44  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
  45  * kernel will keep the negative response cached for up to the time given
  46  * here, although the time can be shorter if the kernel throws the dcache
  47  * entry away.  This probably should be settable from user space.
  48  */
  49 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ) /* 1 minute */
  50
  51 /* Unified info structure.  This is pointed to by both the dentry and
  52    inode structures.  Each file in the filesystem has an instance of this
  53    structure.  It holds a reference to the dentry, so dentries are never
  54    flushed while the file exists.  All name lookups are dealt with at the
  55    dentry level, although the filesystem can interfere in the validation
  56    process.  Readdir is implemented by traversing the dentry lists. */
  57 struct autofs_info {
  58         struct dentry   *dentry;
  59         struct inode    *inode;
  60
  61         int             flags;
  62
  63         struct autofs_sb_info *sbi;
  64         unsigned long last_used;
  65
  66         mode_t  mode;
  67         size_t  size;
  68
  69         void (*free)(struct autofs_info *);
  70         union {
  71                 const char *symlink;
  72         } u;
  73 };
  74
  75 #define AUTOFS_INF_EXPIRING     (1<<0) /* dentry is in the process of expiring */
  76
  77 struct autofs_wait_queue {
  78         wait_queue_head_t queue;
  79         struct autofs_wait_queue *next;
  80         autofs_wqt_t wait_queue_token;
  81         /* We use the following to see what we are waiting for */
  82         int hash;
  83         int len;
  84         char *name;
  85         /* This is for status reporting upon return */
  86         int status;
  87         atomic_t wait_ctr;
  88 };
  89
  90 #define AUTOFS_SBI_MAGIC 0x6d4a556d
  91
  92 struct autofs_sb_info {
  93         u32 magic;
  94         struct file *pipe;
  95         pid_t oz_pgrp;
  96         int catatonic;
  97         int version;
  98         int sub_version;
  99         unsigned long exp_timeout;
 100         int reghost_enabled;
 101         int needs_reghost;
 102         struct super_block *sb;
 103         struct semaphore wq_sem;
 104         struct autofs_wait_queue *queues; /* Wait queue pointer */
 105 };
 106
 107 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
 108 {
 109         return (struct autofs_sb_info *)(sb->s_fs_info);
 110 }
 111
 112 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
 113 {
 114         return (struct autofs_info *)(dentry->d_fsdata);
 115 }
 116
 117 /* autofs4_oz_mode(): do we see the man behind the curtain?  (The
 118    processes which do manipulations for us in user space sees the raw
 119    filesystem without "magic".) */
 120
 121 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
 122         return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
 123 }
 124
 125 /* Does a dentry have some pending activity? */
 126 static inline int autofs4_ispending(struct dentry *dentry)
 127 {
 128         struct autofs_info *inf = autofs4_dentry_ino(dentry);
 129
 130         return (dentry->d_flags & DCACHE_AUTOFS_PENDING) ||
 131                 (inf != NULL && inf->flags & AUTOFS_INF_EXPIRING);
 132 }
 133
 134 static inline void autofs4_copy_atime(struct file *src, struct file *dst)
 135 {
 136         dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
 137         return;
 138 }
 139
 140 struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
 141 void autofs4_free_ino(struct autofs_info *);
 142
 143 /* Expiration */
 144 int is_autofs4_dentry(struct dentry *);
 145 int autofs4_expire_run(struct super_block *, struct vfsmount *,
 146                         struct autofs_sb_info *,
 147                         struct autofs_packet_expire __user *);
 148 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 149                         struct autofs_sb_info *, int __user *);
 150
 151 /* Operations structures */
 152
 153 extern struct inode_operations autofs4_symlink_inode_operations;
 154 extern struct inode_operations autofs4_dir_inode_operations;
 155 extern struct inode_operations autofs4_root_inode_operations;
 156 extern struct file_operations autofs4_dir_operations;
 157 extern struct file_operations autofs4_root_operations;
 158
 159 /* Initializing function */
 160
 161 int autofs4_fill_super(struct super_block *, void *, int);
 162 struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
 163
 164 /* Queue management functions */
 165
 166 enum autofs_notify
 167 {
 168         NFY_NONE,
 169         NFY_MOUNT,
 170         NFY_EXPIRE
 171 };
 172
 173 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 174 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 175 void autofs4_catatonic_mode(struct autofs_sb_info *);
 176
 177 static inline int simple_positive(struct dentry *dentry)
 178 {
 179         return dentry->d_inode && !d_unhashed(dentry);
 180 }
 181
 182 static inline int simple_empty_nolock(struct dentry *dentry)
 183 {
 184         struct dentry *child;
 185         int ret = 0;
 186
 187         list_for_each_entry(child, &dentry->d_subdirs, d_child)
 188                 if (simple_positive(child))
 189                         goto out;
 190         ret = 1;
 191 out:
 192         return ret;
 193 }