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_fs.h> 13 #include <linux/auto_dev-ioctl.h> 14 15 #include <linux/kernel.h> 16 #include <linux/slab.h> 17 #include <linux/time.h> 18 #include <linux/string.h> 19 #include <linux/wait.h> 20 #include <linux/sched.h> 21 #include <linux/mount.h> 22 #include <linux/namei.h> 23 #include <linux/uaccess.h> 24 #include <linux/mutex.h> 25 #include <linux/spinlock.h> 26 #include <linux/list.h> 27 #include <linux/completion.h> 28 #include <linux/file.h> 29 30 /* This is the range of ioctl() numbers we claim as ours */ 31 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY 32 #define AUTOFS_IOC_COUNT 32 33 34 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION) 35 #define AUTOFS_DEV_IOCTL_IOC_COUNT \ 36 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD) 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 */ 51 struct 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_WANT_EXPIRE (1<<1) /* the dentry is being considered 74 * for expiry, so RCU_walk is 75 * not permitted. If it progresses to 76 * actual expiry attempt, the flag is 77 * not cleared when EXPIRING is set - 78 * in that case it gets cleared only 79 * when it comes to clearing EXPIRING. 80 */ 81 #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */ 82 83 struct autofs_wait_queue { 84 wait_queue_head_t queue; 85 struct autofs_wait_queue *next; 86 autofs_wqt_t wait_queue_token; 87 /* We use the following to see what we are waiting for */ 88 struct qstr name; 89 u32 dev; 90 u64 ino; 91 kuid_t uid; 92 kgid_t gid; 93 pid_t pid; 94 pid_t tgid; 95 /* This is for status reporting upon return */ 96 int status; 97 unsigned int wait_ctr; 98 }; 99 100 #define AUTOFS_SBI_MAGIC 0x6d4a556d 101 102 struct autofs_sb_info { 103 u32 magic; 104 int pipefd; 105 struct file *pipe; 106 struct pid *oz_pgrp; 107 int catatonic; 108 int version; 109 int sub_version; 110 int min_proto; 111 int max_proto; 112 unsigned long exp_timeout; 113 unsigned int type; 114 struct super_block *sb; 115 struct mutex wq_mutex; 116 struct mutex pipe_mutex; 117 spinlock_t fs_lock; 118 struct autofs_wait_queue *queues; /* Wait queue pointer */ 119 spinlock_t lookup_lock; 120 struct list_head active_list; 121 struct list_head expiring_list; 122 struct rcu_head rcu; 123 }; 124 125 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 126 { 127 return (struct autofs_sb_info *)(sb->s_fs_info); 128 } 129 130 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 131 { 132 return (struct autofs_info *)(dentry->d_fsdata); 133 } 134 135 /* autofs_oz_mode(): do we see the man behind the curtain? (The 136 * processes which do manipulations for us in user space sees the raw 137 * filesystem without "magic".) 138 */ 139 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 140 { 141 return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp; 142 } 143 144 struct inode *autofs_get_inode(struct super_block *, umode_t); 145 void autofs_free_ino(struct autofs_info *); 146 147 /* Expiration */ 148 int is_autofs_dentry(struct dentry *); 149 int autofs_expire_wait(const struct path *path, int rcu_walk); 150 int autofs_expire_run(struct super_block *, struct vfsmount *, 151 struct autofs_sb_info *, 152 struct autofs_packet_expire __user *); 153 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 154 struct autofs_sb_info *sbi, int when); 155 int autofs_expire_multi(struct super_block *, struct vfsmount *, 156 struct autofs_sb_info *, int __user *); 157 struct dentry *autofs_expire_direct(struct super_block *sb, 158 struct vfsmount *mnt, 159 struct autofs_sb_info *sbi, int how); 160 struct dentry *autofs_expire_indirect(struct super_block *sb, 161 struct vfsmount *mnt, 162 struct autofs_sb_info *sbi, int how); 163 164 /* Device node initialization */ 165 166 int autofs_dev_ioctl_init(void); 167 void autofs_dev_ioctl_exit(void); 168 169 /* Operations structures */ 170 171 extern const struct inode_operations autofs_symlink_inode_operations; 172 extern const struct inode_operations autofs_dir_inode_operations; 173 extern const struct file_operations autofs_dir_operations; 174 extern const struct file_operations autofs_root_operations; 175 extern const struct dentry_operations autofs_dentry_operations; 176 177 /* VFS automount flags management functions */ 178 static inline void __managed_dentry_set_managed(struct dentry *dentry) 179 { 180 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 181 } 182 183 static inline void managed_dentry_set_managed(struct dentry *dentry) 184 { 185 spin_lock(&dentry->d_lock); 186 __managed_dentry_set_managed(dentry); 187 spin_unlock(&dentry->d_lock); 188 } 189 190 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 191 { 192 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 193 } 194 195 static inline void managed_dentry_clear_managed(struct dentry *dentry) 196 { 197 spin_lock(&dentry->d_lock); 198 __managed_dentry_clear_managed(dentry); 199 spin_unlock(&dentry->d_lock); 200 } 201 202 /* Initializing function */ 203 204 int autofs_fill_super(struct super_block *, void *, int); 205 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 206 void autofs_clean_ino(struct autofs_info *); 207 208 static inline int autofs_prepare_pipe(struct file *pipe) 209 { 210 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 211 return -EINVAL; 212 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 213 return -EINVAL; 214 /* We want a packet pipe */ 215 pipe->f_flags |= O_DIRECT; 216 return 0; 217 } 218 219 /* Queue management functions */ 220 221 int autofs_wait(struct autofs_sb_info *, 222 const struct path *, enum autofs_notify); 223 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 224 void autofs_catatonic_mode(struct autofs_sb_info *); 225 226 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 227 { 228 return new_encode_dev(sbi->sb->s_dev); 229 } 230 231 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 232 { 233 return d_inode(sbi->sb->s_root)->i_ino; 234 } 235 236 static inline void __autofs_add_expiring(struct dentry *dentry) 237 { 238 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 239 struct autofs_info *ino = autofs_dentry_ino(dentry); 240 241 if (ino) { 242 if (list_empty(&ino->expiring)) 243 list_add(&ino->expiring, &sbi->expiring_list); 244 } 245 } 246 247 static inline void autofs_add_expiring(struct dentry *dentry) 248 { 249 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 250 struct autofs_info *ino = autofs_dentry_ino(dentry); 251 252 if (ino) { 253 spin_lock(&sbi->lookup_lock); 254 if (list_empty(&ino->expiring)) 255 list_add(&ino->expiring, &sbi->expiring_list); 256 spin_unlock(&sbi->lookup_lock); 257 } 258 } 259 260 static inline void autofs_del_expiring(struct dentry *dentry) 261 { 262 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 263 struct autofs_info *ino = autofs_dentry_ino(dentry); 264 265 if (ino) { 266 spin_lock(&sbi->lookup_lock); 267 if (!list_empty(&ino->expiring)) 268 list_del_init(&ino->expiring); 269 spin_unlock(&sbi->lookup_lock); 270 } 271 } 272 273 void autofs_kill_sb(struct super_block *); 274