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
configfs_is_root(struct config_item * item)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
configfs_fill_super(struct super_block * sb,void * data,int silent)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
configfs_do_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)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
configfs_pin_fs(void)121 int configfs_pin_fs(void)
122 {
123 return simple_pin_fs(&configfs_fs_type, &configfs_mount,
124 &configfs_mnt_count);
125 }
126
configfs_release_fs(void)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
configfs_init(void)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
configfs_exit(void)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);
188