LXR linux/fs/configfs/mount.c

   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
  40struct vfsmount * configfs_mount = NULL;
  41struct super_block * configfs_sb = NULL;
  42struct kmem_cache *configfs_dir_cachep;
  43static int configfs_mnt_count = 0;
  44
  45static const struct super_operations configfs_ops = {
  46        .statfs         = simple_statfs,
  47        .drop_inode     = generic_delete_inode,
  48};
  49
  50static 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
  57int configfs_is_root(struct config_item *item)
  58{
  59        return item == &configfs_root_group.cg_item;
  60}
  61
  62static 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
  70static 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        sb->s_d_op = &configfs_dentry_ops; /* the rest get that */
 105        return 0;
 106}
 107
 108static struct dentry *configfs_do_mount(struct file_system_type *fs_type,
 109        int flags, const char *dev_name, void *data)
 110{
 111        return mount_single(fs_type, flags, data, configfs_fill_super);
 112}
 113
 114static struct file_system_type configfs_fs_type = {
 115        .owner          = THIS_MODULE,
 116        .name           = "configfs",
 117        .mount          = configfs_do_mount,
 118        .kill_sb        = kill_litter_super,
 119};
 120
 121int configfs_pin_fs(void)
 122{
 123        return simple_pin_fs(&configfs_fs_type, &configfs_mount,
 124                             &configfs_mnt_count);
 125}
 126
 127void configfs_release_fs(void)
 128{
 129        simple_release_fs(&configfs_mount, &configfs_mnt_count);
 130}
 131
 132
 133static struct kobject *config_kobj;
 134
 135static int __init configfs_init(void)
 136{
 137        int err = -ENOMEM;
 138
 139        configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
 140                                                sizeof(struct configfs_dirent),
 141                                                0, 0, NULL);
 142        if (!configfs_dir_cachep)
 143                goto out;
 144
 145        config_kobj = kobject_create_and_add("config", kernel_kobj);
 146        if (!config_kobj)
 147                goto out2;
 148
 149        err = configfs_inode_init();
 150        if (err)
 151                goto out3;
 152
 153        err = register_filesystem(&configfs_fs_type);
 154        if (err)
 155                goto out4;
 156
 157        return 0;
 158out4:
 159        printk(KERN_ERR "configfs: Unable to register filesystem!\n");
 160        configfs_inode_exit();
 161out3:
 162        kobject_put(config_kobj);
 163out2:
 164        kmem_cache_destroy(configfs_dir_cachep);
 165        configfs_dir_cachep = NULL;
 166out:
 167        return err;
 168}
 169
 170static void __exit configfs_exit(void)
 171{
 172        unregister_filesystem(&configfs_fs_type);
 173        kobject_put(config_kobj);
 174        kmem_cache_destroy(configfs_dir_cachep);
 175        configfs_dir_cachep = NULL;
 176        configfs_inode_exit();
 177}
 178
 179MODULE_AUTHOR("Oracle");
 180MODULE_LICENSE("GPL");
 181MODULE_VERSION("0.0.2");
 182MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
 183
 184module_init(configfs_init);
 185module_exit(configfs_exit);
 186