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 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 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 return 0; 105 } 106 107 static int configfs_get_sb(struct file_system_type *fs_type, 108 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 109 { 110 return get_sb_single(fs_type, flags, data, configfs_fill_super, mnt); 111 } 112 113 static struct file_system_type configfs_fs_type = { 114 .owner = THIS_MODULE, 115 .name = "configfs", 116 .get_sb = configfs_get_sb, 117 .kill_sb = kill_litter_super, 118 }; 119 120 int configfs_pin_fs(void) 121 { 122 return simple_pin_fs(&configfs_fs_type, &configfs_mount, 123 &configfs_mnt_count); 124 } 125 126 void configfs_release_fs(void) 127 { 128 simple_release_fs(&configfs_mount, &configfs_mnt_count); 129 } 130 131 132 static struct kobject *config_kobj; 133 134 static int __init configfs_init(void) 135 { 136 int err = -ENOMEM; 137 138 configfs_dir_cachep = kmem_cache_create("configfs_dir_cache", 139 sizeof(struct configfs_dirent), 140 0, 0, NULL); 141 if (!configfs_dir_cachep) 142 goto out; 143 144 config_kobj = kobject_create_and_add("config", kernel_kobj); 145 if (!config_kobj) { 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 kobject_put(config_kobj); 155 kmem_cache_destroy(configfs_dir_cachep); 156 configfs_dir_cachep = NULL; 157 goto out; 158 } 159 160 err = configfs_inode_init(); 161 if (err) { 162 unregister_filesystem(&configfs_fs_type); 163 kobject_put(config_kobj); 164 kmem_cache_destroy(configfs_dir_cachep); 165 configfs_dir_cachep = NULL; 166 } 167 out: 168 return err; 169 } 170 171 static void __exit configfs_exit(void) 172 { 173 unregister_filesystem(&configfs_fs_type); 174 kobject_put(config_kobj); 175 kmem_cache_destroy(configfs_dir_cachep); 176 configfs_dir_cachep = NULL; 177 configfs_inode_exit(); 178 } 179 180 MODULE_AUTHOR("Oracle"); 181 MODULE_LICENSE("GPL"); 182 MODULE_VERSION("0.0.2"); 183 MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration."); 184 185 module_init(configfs_init); 186 module_exit(configfs_exit); 187