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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 <asm/current.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 *); |