Line data Source code
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 :
33 : #include <linux/configfs.h>
34 : #include "configfs_internal.h"
35 :
36 : /* Random magic number */
37 : #define CONFIGFS_MAGIC 0x62656570
38 :
39 1 : struct vfsmount * configfs_mount = NULL;
40 1 : struct super_block * configfs_sb = NULL;
41 : struct kmem_cache *configfs_dir_cachep;
42 1 : static int configfs_mnt_count = 0;
43 :
44 1 : static const struct super_operations configfs_ops = {
45 : .statfs = simple_statfs,
46 : .drop_inode = generic_delete_inode,
47 : };
48 :
49 1 : static struct config_group configfs_root_group = {
50 : .cg_item = {
51 : .ci_namebuf = "root",
52 : .ci_name = configfs_root_group.cg_item.ci_namebuf,
53 : },
54 : };
55 :
56 : int configfs_is_root(struct config_item *item)
57 : {
58 4 : return item == &configfs_root_group.cg_item;
59 : }
60 :
61 1 : static struct configfs_dirent configfs_root = {
62 : .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling),
63 : .s_children = LIST_HEAD_INIT(configfs_root.s_children),
64 : .s_element = &configfs_root_group.cg_item,
65 : .s_type = CONFIGFS_ROOT,
66 : .s_iattr = NULL,
67 : };
68 :
69 : static int configfs_fill_super(struct super_block *sb, void *data, int silent)
70 : {
71 0 : struct inode *inode;
72 0 : struct dentry *root;
73 :
74 0 : sb->s_blocksize = PAGE_CACHE_SIZE;
75 0 : sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
76 0 : sb->s_magic = CONFIGFS_MAGIC;
77 0 : sb->s_op = &configfs_ops;
78 0 : sb->s_time_gran = 1;
79 0 : configfs_sb = sb;
80 :
81 0 : inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
82 : &configfs_root);
83 0 : if (inode) {
84 0 : inode->i_op = &configfs_dir_inode_operations;
85 0 : inode->i_fop = &configfs_dir_operations;
86 : /* directory inodes start off with i_nlink == 2 (for "." entry) */
87 0 : inc_nlink(inode);
88 : } else {
89 : pr_debug("configfs: could not get root inode\n");
90 0 : return -ENOMEM;
91 : }
92 :
93 0 : root = d_alloc_root(inode);
94 0 : if (!root) {
95 : pr_debug("%s: could not get root dentry!\n",__func__);
96 0 : iput(inode);
97 0 : return -ENOMEM;
98 : }
99 0 : config_group_init(&configfs_root_group);
100 0 : configfs_root_group.cg_item.ci_dentry = root;
101 0 : root->d_fsdata = &configfs_root;
102 0 : sb->s_root = root;
103 0 : return 0;
104 : }
105 :
106 : static int configfs_get_sb(struct file_system_type *fs_type,
107 : int flags, const char *dev_name, void *data, struct vfsmount *mnt)
108 : {
109 3 : return get_sb_single(fs_type, flags, data, configfs_fill_super, mnt);
110 : }
111 :
112 1 : static struct file_system_type configfs_fs_type = {
113 : .owner = THIS_MODULE,
114 : .name = "configfs",
115 : .get_sb = configfs_get_sb,
116 : .kill_sb = kill_litter_super,
117 : };
118 :
119 : int configfs_pin_fs(void)
120 : {
121 0 : return simple_pin_fs(&configfs_fs_type, &configfs_mount,
122 : &configfs_mnt_count);
123 : }
124 :
125 : void configfs_release_fs(void)
126 : {
127 0 : simple_release_fs(&configfs_mount, &configfs_mnt_count);
128 0 : }
129 :
130 :
131 1 : static struct kobject *config_kobj;
132 :
133 : static int __init configfs_init(void)
134 : {
135 2 : int err = -ENOMEM;
136 :
137 1 : configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
138 : sizeof(struct configfs_dirent),
139 : 0, 0, NULL);
140 2 : if (!configfs_dir_cachep)
141 1 : goto out;
142 :
143 1 : config_kobj = kobject_create_and_add("config", kernel_kobj);
144 2 : if (!config_kobj) {
145 1 : kmem_cache_destroy(configfs_dir_cachep);
146 1 : configfs_dir_cachep = NULL;
147 1 : goto out;
148 : }
149 :
150 2 : err = register_filesystem(&configfs_fs_type);
151 2 : if (err) {
152 1 : printk(KERN_ERR "configfs: Unable to register filesystem!\n");
153 1 : kobject_put(config_kobj);
154 1 : kmem_cache_destroy(configfs_dir_cachep);
155 1 : configfs_dir_cachep = NULL;
156 1 : goto out;
157 : }
158 :
159 2 : err = configfs_inode_init();
160 2 : if (err) {
161 2 : unregister_filesystem(&configfs_fs_type);
162 1 : kobject_put(config_kobj);
163 1 : kmem_cache_destroy(configfs_dir_cachep);
164 1 : configfs_dir_cachep = NULL;
165 : }
166 : out:
167 4 : return err;
168 : }
169 2 :
170 : static void __exit configfs_exit(void)
171 : {
172 4 : unregister_filesystem(&configfs_fs_type);
173 2 : kobject_put(config_kobj);
174 2 : kmem_cache_destroy(configfs_dir_cachep);
175 2 : configfs_dir_cachep = NULL;
176 4 : configfs_inode_exit();
177 2 : }
178 :
179 : MODULE_AUTHOR("Oracle");
180 : MODULE_LICENSE("GPL");
181 : MODULE_VERSION("0.0.2");
182 : MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
183 :
184 : module_init(configfs_init);
185 : module_exit(configfs_exit);
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