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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 | ||
33 | #include <linux/configfs.h> | |
34 | #include "configfs_internal.h" | |
35 | ||
36 | /* Random magic number */ | |
37 | #define CONFIGFS_MAGIC 0x62656570 | |
38 | ||
39 | struct vfsmount * configfs_mount = NULL; | |
40 | struct super_block * configfs_sb = NULL; | |
41 | static int configfs_mnt_count = 0; | |
42 | ||
43 | static struct super_operations configfs_ops = { | |
44 | .statfs = simple_statfs, | |
45 | .drop_inode = generic_delete_inode, | |
46 | }; | |
47 | ||
48 | static struct config_group configfs_root_group = { | |
49 | .cg_item = { | |
50 | .ci_namebuf = "root", | |
51 | .ci_name = configfs_root_group.cg_item.ci_namebuf, | |
52 | }, | |
53 | }; | |
54 | ||
55 | int configfs_is_root(struct config_item *item) | |
56 | { | |
57 | return item == &configfs_root_group.cg_item; | |
58 | } | |
59 | ||
60 | static struct configfs_dirent configfs_root = { | |
61 | .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling), | |
62 | .s_children = LIST_HEAD_INIT(configfs_root.s_children), | |
63 | .s_element = &configfs_root_group.cg_item, | |
64 | .s_type = CONFIGFS_ROOT, | |
65 | }; | |
66 | ||
67 | static int configfs_fill_super(struct super_block *sb, void *data, int silent) | |
68 | { | |
69 | struct inode *inode; | |
70 | struct dentry *root; | |
71 | ||
72 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
73 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
74 | sb->s_magic = CONFIGFS_MAGIC; | |
75 | sb->s_op = &configfs_ops; | |
76 | configfs_sb = sb; | |
77 | ||
78 | inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); | |
79 | if (inode) { | |
80 | inode->i_op = &configfs_dir_inode_operations; | |
81 | inode->i_fop = &configfs_dir_operations; | |
82 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
83 | inode->i_nlink++; | |
84 | } else { | |
85 | pr_debug("configfs: could not get root inode\n"); | |
86 | return -ENOMEM; | |
87 | } | |
88 | ||
89 | root = d_alloc_root(inode); | |
90 | if (!root) { | |
91 | pr_debug("%s: could not get root dentry!\n",__FUNCTION__); | |
92 | iput(inode); | |
93 | return -ENOMEM; | |
94 | } | |
95 | config_group_init(&configfs_root_group); | |
96 | configfs_root_group.cg_item.ci_dentry = root; | |
97 | root->d_fsdata = &configfs_root; | |
98 | sb->s_root = root; | |
99 | return 0; | |
100 | } | |
101 | ||
102 | static struct super_block *configfs_get_sb(struct file_system_type *fs_type, | |
103 | int flags, const char *dev_name, void *data) | |
104 | { | |
105 | return get_sb_single(fs_type, flags, data, configfs_fill_super); | |
106 | } | |
107 | ||
108 | static struct file_system_type configfs_fs_type = { | |
109 | .owner = THIS_MODULE, | |
110 | .name = "configfs", | |
111 | .get_sb = configfs_get_sb, | |
112 | .kill_sb = kill_litter_super, | |
113 | }; | |
114 | ||
115 | int configfs_pin_fs(void) | |
116 | { | |
117 | return simple_pin_fs("configfs", &configfs_mount, | |
118 | &configfs_mnt_count); | |
119 | } | |
120 | ||
121 | void configfs_release_fs(void) | |
122 | { | |
123 | simple_release_fs(&configfs_mount, &configfs_mnt_count); | |
124 | } | |
125 | ||
126 | ||
127 | static decl_subsys(config, NULL, NULL); | |
128 | ||
129 | static int __init configfs_init(void) | |
130 | { | |
131 | int err; | |
132 | ||
133 | kset_set_kset_s(&config_subsys, kernel_subsys); | |
134 | err = subsystem_register(&config_subsys); | |
135 | if (err) | |
136 | return err; | |
137 | ||
138 | err = register_filesystem(&configfs_fs_type); | |
139 | if (err) { | |
140 | printk(KERN_ERR "configfs: Unable to register filesystem!\n"); | |
141 | subsystem_unregister(&config_subsys); | |
142 | } | |
143 | ||
144 | return err; | |
145 | } | |
146 | ||
147 | static void __exit configfs_exit(void) | |
148 | { | |
149 | unregister_filesystem(&configfs_fs_type); | |
150 | subsystem_unregister(&config_subsys); | |
151 | } | |
152 | ||
153 | MODULE_AUTHOR("Oracle"); | |
154 | MODULE_LICENSE("GPL"); | |
155 | MODULE_VERSION("0.0.1"); | |
156 | MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration."); | |
157 | ||
158 | module_init(configfs_init); | |
159 | module_exit(configfs_exit); |