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1 | /* -*- mode: c; c-basic-offset: 8; -*- | |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * mount.c - operations for initializing and mounting configfs. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public | |
17 | * License along with this program; if not, write to the | |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | * Boston, MA 021110-1307, USA. | |
20 | * | |
21 | * Based on sysfs: | |
22 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
23 | * | |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | */ | |
26 | ||
27 | #include <linux/fs.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/mount.h> | |
30 | #include <linux/pagemap.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/slab.h> | |
33 | ||
34 | #include <linux/configfs.h> | |
35 | #include "configfs_internal.h" | |
36 | ||
37 | /* Random magic number */ | |
38 | #define CONFIGFS_MAGIC 0x62656570 | |
39 | ||
40 | struct vfsmount * configfs_mount = NULL; | |
41 | struct super_block * configfs_sb = NULL; | |
42 | struct kmem_cache *configfs_dir_cachep; | |
43 | static int configfs_mnt_count = 0; | |
44 | ||
45 | static const struct super_operations configfs_ops = { | |
46 | .statfs = simple_statfs, | |
47 | .drop_inode = generic_delete_inode, | |
48 | }; | |
49 | ||
50 | static struct config_group configfs_root_group = { | |
51 | .cg_item = { | |
52 | .ci_namebuf = "root", | |
53 | .ci_name = configfs_root_group.cg_item.ci_namebuf, | |
54 | }, | |
55 | }; | |
56 | ||
57 | int configfs_is_root(struct config_item *item) | |
58 | { | |
59 | return item == &configfs_root_group.cg_item; | |
60 | } | |
61 | ||
62 | static struct configfs_dirent configfs_root = { | |
63 | .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling), | |
64 | .s_children = LIST_HEAD_INIT(configfs_root.s_children), | |
65 | .s_element = &configfs_root_group.cg_item, | |
66 | .s_type = CONFIGFS_ROOT, | |
67 | .s_iattr = NULL, | |
68 | }; | |
69 | ||
70 | static int configfs_fill_super(struct super_block *sb, void *data, int silent) | |
71 | { | |
72 | struct inode *inode; | |
73 | struct dentry *root; | |
74 | ||
75 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
76 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
77 | sb->s_magic = CONFIGFS_MAGIC; | |
78 | sb->s_op = &configfs_ops; | |
79 | sb->s_time_gran = 1; | |
80 | configfs_sb = sb; | |
81 | ||
82 | inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, | |
83 | &configfs_root); | |
84 | if (inode) { | |
85 | inode->i_op = &configfs_dir_inode_operations; | |
86 | inode->i_fop = &configfs_dir_operations; | |
87 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
88 | inc_nlink(inode); | |
89 | } else { | |
90 | pr_debug("configfs: could not get root inode\n"); | |
91 | return -ENOMEM; | |
92 | } | |
93 | ||
94 | root = d_alloc_root(inode); | |
95 | if (!root) { | |
96 | pr_debug("%s: could not get root dentry!\n",__func__); | |
97 | iput(inode); | |
98 | return -ENOMEM; | |
99 | } | |
100 | config_group_init(&configfs_root_group); | |
101 | configfs_root_group.cg_item.ci_dentry = root; | |
102 | root->d_fsdata = &configfs_root; | |
103 | sb->s_root = root; | |
104 | sb->s_d_op = &configfs_dentry_ops; /* the rest get that */ | |
105 | return 0; | |
106 | } | |
107 | ||
108 | static struct dentry *configfs_do_mount(struct file_system_type *fs_type, | |
109 | int flags, const char *dev_name, void *data) | |
110 | { | |
111 | return mount_single(fs_type, flags, data, configfs_fill_super); | |
112 | } | |
113 | ||
114 | static struct file_system_type configfs_fs_type = { | |
115 | .owner = THIS_MODULE, | |
116 | .name = "configfs", | |
117 | .mount = configfs_do_mount, | |
118 | .kill_sb = kill_litter_super, | |
119 | }; | |
120 | ||
121 | int configfs_pin_fs(void) | |
122 | { | |
123 | return simple_pin_fs(&configfs_fs_type, &configfs_mount, | |
124 | &configfs_mnt_count); | |
125 | } | |
126 | ||
127 | void configfs_release_fs(void) | |
128 | { | |
129 | simple_release_fs(&configfs_mount, &configfs_mnt_count); | |
130 | } | |
131 | ||
132 | ||
133 | static struct kobject *config_kobj; | |
134 | ||
135 | static int __init configfs_init(void) | |
136 | { | |
137 | int err = -ENOMEM; | |
138 | ||
139 | configfs_dir_cachep = kmem_cache_create("configfs_dir_cache", | |
140 | sizeof(struct configfs_dirent), | |
141 | 0, 0, NULL); | |
142 | if (!configfs_dir_cachep) | |
143 | goto out; | |
144 | ||
145 | config_kobj = kobject_create_and_add("config", kernel_kobj); | |
146 | if (!config_kobj) { | |
147 | kmem_cache_destroy(configfs_dir_cachep); | |
148 | configfs_dir_cachep = NULL; | |
149 | goto out; | |
150 | } | |
151 | ||
152 | err = register_filesystem(&configfs_fs_type); | |
153 | if (err) { | |
154 | printk(KERN_ERR "configfs: Unable to register filesystem!\n"); | |
155 | kobject_put(config_kobj); | |
156 | kmem_cache_destroy(configfs_dir_cachep); | |
157 | configfs_dir_cachep = NULL; | |
158 | goto out; | |
159 | } | |
160 | ||
161 | err = configfs_inode_init(); | |
162 | if (err) { | |
163 | unregister_filesystem(&configfs_fs_type); | |
164 | kobject_put(config_kobj); | |
165 | kmem_cache_destroy(configfs_dir_cachep); | |
166 | configfs_dir_cachep = NULL; | |
167 | } | |
168 | out: | |
169 | return err; | |
170 | } | |
171 | ||
172 | static void __exit configfs_exit(void) | |
173 | { | |
174 | unregister_filesystem(&configfs_fs_type); | |
175 | kobject_put(config_kobj); | |
176 | kmem_cache_destroy(configfs_dir_cachep); | |
177 | configfs_dir_cachep = NULL; | |
178 | configfs_inode_exit(); | |
179 | } | |
180 | ||
181 | MODULE_AUTHOR("Oracle"); | |
182 | MODULE_LICENSE("GPL"); | |
183 | MODULE_VERSION("0.0.2"); | |
184 | MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration."); | |
185 | ||
186 | module_init(configfs_init); | |
187 | module_exit(configfs_exit); |