xref: /openbmc/linux/fs/autofs/autofs_i.h (revision 87c2ce3b)
1 /* -*- linux-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_fs.h>
16 
17 /* This is the range of ioctl() numbers we claim as ours */
18 #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
19 #define AUTOFS_IOC_COUNT     32
20 
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/time.h>
24 #include <linux/string.h>
25 #include <linux/wait.h>
26 #include <linux/dcache.h>
27 #include <linux/namei.h>
28 #include <linux/mount.h>
29 #include <linux/sched.h>
30 
31 #include <asm/current.h>
32 #include <asm/uaccess.h>
33 
34 #ifdef DEBUG
35 #define DPRINTK(D) (printk D)
36 #else
37 #define DPRINTK(D) ((void)0)
38 #endif
39 
40 #define AUTOFS_SUPER_MAGIC 0x0187
41 
42 /*
43  * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
44  * kernel will keep the negative response cached for up to the time given
45  * here, although the time can be shorter if the kernel throws the dcache
46  * entry away.  This probably should be settable from user space.
47  */
48 #define AUTOFS_NEGATIVE_TIMEOUT (60*HZ)	/* 1 minute */
49 
50 /* Structures associated with the root directory hash table */
51 
52 #define AUTOFS_HASH_SIZE 67
53 
54 struct autofs_dir_ent {
55 	int hash;
56 	char *name;
57 	int len;
58 	ino_t ino;
59 	struct dentry *dentry;
60 	/* Linked list of entries */
61 	struct autofs_dir_ent *next;
62 	struct autofs_dir_ent **back;
63 	/* The following entries are for the expiry system */
64 	unsigned long last_usage;
65 	struct list_head exp;
66 };
67 
68 struct autofs_dirhash {
69 	struct autofs_dir_ent *h[AUTOFS_HASH_SIZE];
70 	struct list_head expiry_head;
71 };
72 
73 struct autofs_wait_queue {
74 	wait_queue_head_t queue;
75 	struct autofs_wait_queue *next;
76 	autofs_wqt_t wait_queue_token;
77 	/* We use the following to see what we are waiting for */
78 	int hash;
79 	int len;
80 	char *name;
81 	/* This is for status reporting upon return */
82 	int status;
83 	int wait_ctr;
84 };
85 
86 struct autofs_symlink {
87 	char *data;
88 	int len;
89 	time_t mtime;
90 };
91 
92 #define AUTOFS_MAX_SYMLINKS 256
93 
94 #define AUTOFS_ROOT_INO      1
95 #define AUTOFS_FIRST_SYMLINK 2
96 #define AUTOFS_FIRST_DIR_INO (AUTOFS_FIRST_SYMLINK+AUTOFS_MAX_SYMLINKS)
97 
98 #define AUTOFS_SYMLINK_BITMAP_LEN \
99 	((AUTOFS_MAX_SYMLINKS+((sizeof(long)*1)-1))/(sizeof(long)*8))
100 
101 #define AUTOFS_SBI_MAGIC 0x6d4a556d
102 
103 struct autofs_sb_info {
104 	u32 magic;
105 	struct file *pipe;
106 	pid_t oz_pgrp;
107 	int catatonic;
108 	struct super_block *sb;
109 	unsigned long exp_timeout;
110 	ino_t next_dir_ino;
111 	struct autofs_wait_queue *queues; /* Wait queue pointer */
112 	struct autofs_dirhash dirhash; /* Root directory hash */
113 	struct autofs_symlink symlink[AUTOFS_MAX_SYMLINKS];
114 	unsigned long symlink_bitmap[AUTOFS_SYMLINK_BITMAP_LEN];
115 };
116 
117 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
118 {
119 	return (struct autofs_sb_info *)(sb->s_fs_info);
120 }
121 
122 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
123    processes which do manipulations for us in user space sees the raw
124    filesystem without "magic".) */
125 
126 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
127 	return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
128 }
129 
130 /* Hash operations */
131 
132 void autofs_initialize_hash(struct autofs_dirhash *);
133 struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *,struct qstr *);
134 void autofs_hash_insert(struct autofs_dirhash *,struct autofs_dir_ent *);
135 void autofs_hash_delete(struct autofs_dir_ent *);
136 struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *,off_t *,struct autofs_dir_ent *);
137 void autofs_hash_dputall(struct autofs_dirhash *);
138 void autofs_hash_nuke(struct autofs_sb_info *);
139 
140 /* Expiration-handling functions */
141 
142 void autofs_update_usage(struct autofs_dirhash *,struct autofs_dir_ent *);
143 struct autofs_dir_ent *autofs_expire(struct super_block *,struct autofs_sb_info *, struct vfsmount *mnt);
144 
145 /* Operations structures */
146 
147 extern struct inode_operations autofs_root_inode_operations;
148 extern struct inode_operations autofs_symlink_inode_operations;
149 extern struct file_operations autofs_root_operations;
150 
151 /* Initializing function */
152 
153 int autofs_fill_super(struct super_block *, void *, int);
154 
155 /* Queue management functions */
156 
157 int autofs_wait(struct autofs_sb_info *,struct qstr *);
158 int autofs_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
159 void autofs_catatonic_mode(struct autofs_sb_info *);
160 
161 #ifdef DEBUG
162 void autofs_say(const char *name, int len);
163 #else
164 #define autofs_say(n,l) ((void)0)
165 #endif
166