linux/fs/configfs/mount.c
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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
  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);
 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                goto out;
 158        }
 159
 160        err = configfs_inode_init();
 161        if (err) {
 162                unregister_filesystem(&configfs_fs_type);
 163                subsystem_unregister(&config_subsys);
 164                kmem_cache_destroy(configfs_dir_cachep);
 165                configfs_dir_cachep = NULL;
 166        }
 167out:
 168        return err;
 169}
 170
 171static void __exit configfs_exit(void)
 172{
 173        unregister_filesystem(&configfs_fs_type);
 174        subsystem_unregister(&config_subsys);
 175        kmem_cache_destroy(configfs_dir_cachep);
 176        configfs_dir_cachep = NULL;
 177        configfs_inode_exit();
 178}
 179
 180MODULE_AUTHOR("Oracle");
 181MODULE_LICENSE("GPL");
 182MODULE_VERSION("0.0.2");
 183MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
 184
 185module_init(configfs_init);
 186module_exit(configfs_exit);
 187