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
39struct vfsmount * configfs_mount = NULL;
40struct super_block * configfs_sb = NULL;
41struct kmem_cache *configfs_dir_cachep;
42static int configfs_mnt_count = 0;
43
44static const struct super_operations configfs_ops = {
45	.statfs		= simple_statfs,
46	.drop_inode	= generic_delete_inode,
47};
48
49static 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
56int configfs_is_root(struct config_item *item)
57{
58	return item == &configfs_root_group.cg_item;
59}
60
61static 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
69static int configfs_fill_super(struct super_block *sb, void *data, int silent)
70{
71	struct inode *inode;
72	struct dentry *root;
73
74	sb->s_blocksize = PAGE_CACHE_SIZE;
75	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
76	sb->s_magic = CONFIGFS_MAGIC;
77	sb->s_op = &configfs_ops;
78	sb->s_time_gran = 1;
79	configfs_sb = sb;
80
81	inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
82				   &configfs_root);
83	if (inode) {
84		inode->i_op = &configfs_dir_inode_operations;
85		inode->i_fop = &configfs_dir_operations;
86		/* directory inodes start off with i_nlink == 2 (for "." entry) */
87		inc_nlink(inode);
88	} else {
89		pr_debug("configfs: could not get root inode\n");
90		return -ENOMEM;
91	}
92
93	root = d_alloc_root(inode);
94	if (!root) {
95		pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
96		iput(inode);
97		return -ENOMEM;
98	}
99	config_group_init(&configfs_root_group);
100	configfs_root_group.cg_item.ci_dentry = root;
101	root->d_fsdata = &configfs_root;
102	sb->s_root = root;
103	return 0;
104}
105
106static int configfs_get_sb(struct file_system_type *fs_type,
107	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
108{
109	return get_sb_single(fs_type, flags, data, configfs_fill_super, mnt);
110}
111
112static 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
119int configfs_pin_fs(void)
120{
121	return simple_pin_fs(&configfs_fs_type, &configfs_mount,
122			     &configfs_mnt_count);
123}
124
125void configfs_release_fs(void)
126{
127	simple_release_fs(&configfs_mount, &configfs_mnt_count);
128}
129
130
131static decl_subsys(config, NULL, NULL);
132
133static int __init configfs_init(void)
134{
135	int err = -ENOMEM;
136
137	configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
138						sizeof(struct configfs_dirent),
139						0, 0, NULL, NULL);
140	if (!configfs_dir_cachep)
141		goto out;
142
143	kobj_set_kset_s(&config_subsys, kernel_subsys);
144	err = subsystem_register(&config_subsys);
145	if (err) {
146		kmem_cache_destroy(configfs_dir_cachep);
147		configfs_dir_cachep = NULL;
148		goto out;
149	}
150
151	err = register_filesystem(&configfs_fs_type);
152	if (err) {
153		printk(KERN_ERR "configfs: Unable to register filesystem!\n");
154		subsystem_unregister(&config_subsys);
155		kmem_cache_destroy(configfs_dir_cachep);
156		configfs_dir_cachep = NULL;
157	}
158
159out:
160	return err;
161}
162
163static void __exit configfs_exit(void)
164{
165	unregister_filesystem(&configfs_fs_type);
166	subsystem_unregister(&config_subsys);
167	kmem_cache_destroy(configfs_dir_cachep);
168	configfs_dir_cachep = NULL;
169}
170
171MODULE_AUTHOR("Oracle");
172MODULE_LICENSE("GPL");
173MODULE_VERSION("0.0.2");
174MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
175
176module_init(configfs_init);
177module_exit(configfs_exit);
178