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); 160