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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
40static struct vfsmount *configfs_mount = 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_SIZE;
75 sb->s_blocksize_bits = PAGE_SHIFT;
76 sb->s_magic = CONFIGFS_MAGIC;
77 sb->s_op = &configfs_ops;
78 sb->s_time_gran = 1;
79
80 inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
81 &configfs_root, sb);
82 if (inode) {
83 inode->i_op = &configfs_root_inode_operations;
84 inode->i_fop = &configfs_dir_operations;
85 /* directory inodes start off with i_nlink == 2 (for "." entry) */
86 inc_nlink(inode);
87 } else {
88 pr_debug("could not get root inode\n");
89 return -ENOMEM;
90 }
91
92 root = d_make_root(inode);
93 if (!root) {
94 pr_debug("%s: could not get root dentry!\n",__func__);
95 return -ENOMEM;
96 }
97 config_group_init(&configfs_root_group);
98 configfs_root_group.cg_item.ci_dentry = root;
99 root->d_fsdata = &configfs_root;
100 sb->s_root = root;
101 sb->s_d_op = &configfs_dentry_ops; /* the rest get that */
102 return 0;
103}
104
105static struct dentry *configfs_do_mount(struct file_system_type *fs_type,
106 int flags, const char *dev_name, void *data)
107{
108 return mount_single(fs_type, flags, data, configfs_fill_super);
109}
110
111static struct file_system_type configfs_fs_type = {
112 .owner = THIS_MODULE,
113 .name = "configfs",
114 .mount = configfs_do_mount,
115 .kill_sb = kill_litter_super,
116};
117MODULE_ALIAS_FS("configfs");
118
119struct dentry *configfs_pin_fs(void)
120{
121 int err = simple_pin_fs(&configfs_fs_type, &configfs_mount,
122 &configfs_mnt_count);
123 return err ? ERR_PTR(err) : configfs_mount->mnt_root;
124}
125
126void configfs_release_fs(void)
127{
128 simple_release_fs(&configfs_mount, &configfs_mnt_count);
129}
130
131
132static int __init configfs_init(void)
133{
134 int err = -ENOMEM;
135
136 configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
137 sizeof(struct configfs_dirent),
138 0, 0, NULL);
139 if (!configfs_dir_cachep)
140 goto out;
141
142 err = sysfs_create_mount_point(kernel_kobj, "config");
143 if (err)
144 goto out2;
145
146 err = register_filesystem(&configfs_fs_type);
147 if (err)
148 goto out3;
149
150 return 0;
151out3:
152 pr_err("Unable to register filesystem!\n");
153 sysfs_remove_mount_point(kernel_kobj, "config");
154out2:
155 kmem_cache_destroy(configfs_dir_cachep);
156 configfs_dir_cachep = NULL;
157out:
158 return err;
159}
160
161static void __exit configfs_exit(void)
162{
163 unregister_filesystem(&configfs_fs_type);
164 sysfs_remove_mount_point(kernel_kobj, "config");
165 kmem_cache_destroy(configfs_dir_cachep);
166 configfs_dir_cachep = NULL;
167}
168
169MODULE_AUTHOR("Oracle");
170MODULE_LICENSE("GPL");
171MODULE_VERSION("0.0.2");
172MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
173
174core_initcall(configfs_init);
175module_exit(configfs_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* -*- mode: c; c-basic-offset: 8; -*-
3 * vim: noexpandtab sw=8 ts=8 sts=0:
4 *
5 * mount.c - operations for initializing and mounting configfs.
6 *
7 * Based on sysfs:
8 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
9 *
10 * configfs Copyright (C) 2005 Oracle. All rights reserved.
11 */
12
13#include <linux/fs.h>
14#include <linux/module.h>
15#include <linux/mount.h>
16#include <linux/fs_context.h>
17#include <linux/pagemap.h>
18#include <linux/init.h>
19#include <linux/slab.h>
20
21#include <linux/configfs.h>
22#include "configfs_internal.h"
23
24/* Random magic number */
25#define CONFIGFS_MAGIC 0x62656570
26
27static struct vfsmount *configfs_mount = NULL;
28struct kmem_cache *configfs_dir_cachep;
29static int configfs_mnt_count = 0;
30
31
32static void configfs_free_inode(struct inode *inode)
33{
34 if (S_ISLNK(inode->i_mode))
35 kfree(inode->i_link);
36 free_inode_nonrcu(inode);
37}
38
39static const struct super_operations configfs_ops = {
40 .statfs = simple_statfs,
41 .drop_inode = generic_delete_inode,
42 .free_inode = configfs_free_inode,
43};
44
45static struct config_group configfs_root_group = {
46 .cg_item = {
47 .ci_namebuf = "root",
48 .ci_name = configfs_root_group.cg_item.ci_namebuf,
49 },
50};
51
52int configfs_is_root(struct config_item *item)
53{
54 return item == &configfs_root_group.cg_item;
55}
56
57static struct configfs_dirent configfs_root = {
58 .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling),
59 .s_children = LIST_HEAD_INIT(configfs_root.s_children),
60 .s_element = &configfs_root_group.cg_item,
61 .s_type = CONFIGFS_ROOT,
62 .s_iattr = NULL,
63};
64
65static int configfs_fill_super(struct super_block *sb, struct fs_context *fc)
66{
67 struct inode *inode;
68 struct dentry *root;
69
70 sb->s_blocksize = PAGE_SIZE;
71 sb->s_blocksize_bits = PAGE_SHIFT;
72 sb->s_magic = CONFIGFS_MAGIC;
73 sb->s_op = &configfs_ops;
74 sb->s_time_gran = 1;
75
76 inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
77 &configfs_root, sb);
78 if (inode) {
79 inode->i_op = &configfs_root_inode_operations;
80 inode->i_fop = &configfs_dir_operations;
81 /* directory inodes start off with i_nlink == 2 (for "." entry) */
82 inc_nlink(inode);
83 } else {
84 pr_debug("could not get root inode\n");
85 return -ENOMEM;
86 }
87
88 root = d_make_root(inode);
89 if (!root) {
90 pr_debug("%s: could not get root dentry!\n",__func__);
91 return -ENOMEM;
92 }
93 config_group_init(&configfs_root_group);
94 configfs_root_group.cg_item.ci_dentry = root;
95 root->d_fsdata = &configfs_root;
96 sb->s_root = root;
97 sb->s_d_op = &configfs_dentry_ops; /* the rest get that */
98 return 0;
99}
100
101static int configfs_get_tree(struct fs_context *fc)
102{
103 return get_tree_single(fc, configfs_fill_super);
104}
105
106static const struct fs_context_operations configfs_context_ops = {
107 .get_tree = configfs_get_tree,
108};
109
110static int configfs_init_fs_context(struct fs_context *fc)
111{
112 fc->ops = &configfs_context_ops;
113 return 0;
114}
115
116static struct file_system_type configfs_fs_type = {
117 .owner = THIS_MODULE,
118 .name = "configfs",
119 .init_fs_context = configfs_init_fs_context,
120 .kill_sb = kill_litter_super,
121};
122MODULE_ALIAS_FS("configfs");
123
124struct dentry *configfs_pin_fs(void)
125{
126 int err = simple_pin_fs(&configfs_fs_type, &configfs_mount,
127 &configfs_mnt_count);
128 return err ? ERR_PTR(err) : configfs_mount->mnt_root;
129}
130
131void configfs_release_fs(void)
132{
133 simple_release_fs(&configfs_mount, &configfs_mnt_count);
134}
135
136
137static int __init configfs_init(void)
138{
139 int err = -ENOMEM;
140
141 configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
142 sizeof(struct configfs_dirent),
143 0, 0, NULL);
144 if (!configfs_dir_cachep)
145 goto out;
146
147 err = sysfs_create_mount_point(kernel_kobj, "config");
148 if (err)
149 goto out2;
150
151 err = register_filesystem(&configfs_fs_type);
152 if (err)
153 goto out3;
154
155 return 0;
156out3:
157 pr_err("Unable to register filesystem!\n");
158 sysfs_remove_mount_point(kernel_kobj, "config");
159out2:
160 kmem_cache_destroy(configfs_dir_cachep);
161 configfs_dir_cachep = NULL;
162out:
163 return err;
164}
165
166static void __exit configfs_exit(void)
167{
168 unregister_filesystem(&configfs_fs_type);
169 sysfs_remove_mount_point(kernel_kobj, "config");
170 kmem_cache_destroy(configfs_dir_cachep);
171 configfs_dir_cachep = NULL;
172}
173
174MODULE_AUTHOR("Oracle");
175MODULE_LICENSE("GPL");
176MODULE_VERSION("0.0.2");
177MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
178
179core_initcall(configfs_init);
180module_exit(configfs_exit);