root/fs/configfs/mount.c

DEFINITIONS

1. configfs_is_root
2. configfs_fill_super
3. configfs_get_sb
4. configfs_pin_fs
5. configfs_release_fs
6. configfs_init
7. configfs_exit

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * mount.c - operations for initializing and mounting configfs.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 * Based on sysfs:
 *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>

#include <linux/configfs.h>
#include "configfs_internal.h"

/* Random magic number */
#define CONFIGFS_MAGIC 0x62656570

struct vfsmount * configfs_mount = NULL;
struct super_block * configfs_sb = NULL;
struct kmem_cache *configfs_dir_cachep;
static int configfs_mnt_count = 0;

static const struct super_operations configfs_ops = {
        .statfs         = simple_statfs,
        .drop_inode     = generic_delete_inode,
};

static struct config_group configfs_root_group = {
        .cg_item = {
                .ci_namebuf     = "root",
                .ci_name        = configfs_root_group.cg_item.ci_namebuf,
        },
};

int configfs_is_root(struct config_item *item)
{
        return item == &configfs_root_group.cg_item;
}

static struct configfs_dirent configfs_root = {
        .s_sibling      = LIST_HEAD_INIT(configfs_root.s_sibling),
        .s_children     = LIST_HEAD_INIT(configfs_root.s_children),
        .s_element      = &configfs_root_group.cg_item,
        .s_type         = CONFIGFS_ROOT,
        .s_iattr        = NULL,
};

static int configfs_fill_super(struct super_block *sb, void *data, int silent)
{
        struct inode *inode;
        struct dentry *root;

        sb->s_blocksize = PAGE_CACHE_SIZE;
        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
        sb->s_magic = CONFIGFS_MAGIC;
        sb->s_op = &configfs_ops;
        sb->s_time_gran = 1;
        configfs_sb = sb;

        inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
                                   &configfs_root);
        if (inode) {
                inode->i_op = &configfs_dir_inode_operations;
                inode->i_fop = &configfs_dir_operations;
                /* directory inodes start off with i_nlink == 2 (for "." entry) */
                inc_nlink(inode);
        } else {
                pr_debug("configfs: could not get root inode\n");
                return -ENOMEM;
        }

        root = d_alloc_root(inode);
        if (!root) {
                pr_debug("%s: could not get root dentry!\n",__func__);
                iput(inode);
                return -ENOMEM;
        }
        config_group_init(&configfs_root_group);
        configfs_root_group.cg_item.ci_dentry = root;
        root->d_fsdata = &configfs_root;
        sb->s_root = root;
        return 0;
}

static int configfs_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
        return get_sb_single(fs_type, flags, data, configfs_fill_super, mnt);
}

static struct file_system_type configfs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "configfs",
        .get_sb         = configfs_get_sb,
        .kill_sb        = kill_litter_super,
};

int configfs_pin_fs(void)
{
        return simple_pin_fs(&configfs_fs_type, &configfs_mount,
                             &configfs_mnt_count);
}

void configfs_release_fs(void)
{
        simple_release_fs(&configfs_mount, &configfs_mnt_count);
}


static struct kobject *config_kobj;

static int __init configfs_init(void)
{
        int err = -ENOMEM;

        configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
                                                sizeof(struct configfs_dirent),
                                                0, 0, NULL);
        if (!configfs_dir_cachep)
                goto out;

        config_kobj = kobject_create_and_add("config", kernel_kobj);
        if (!config_kobj) {
                kmem_cache_destroy(configfs_dir_cachep);
                configfs_dir_cachep = NULL;
                goto out;
        }

        err = register_filesystem(&configfs_fs_type);
        if (err) {
                printk(KERN_ERR "configfs: Unable to register filesystem!\n");
                kobject_put(config_kobj);
                kmem_cache_destroy(configfs_dir_cachep);
                configfs_dir_cachep = NULL;
                goto out;
        }

        err = configfs_inode_init();
        if (err) {
                unregister_filesystem(&configfs_fs_type);
                kobject_put(config_kobj);
                kmem_cache_destroy(configfs_dir_cachep);
                configfs_dir_cachep = NULL;
        }
out:
        return err;
}

static void __exit configfs_exit(void)
{
        unregister_filesystem(&configfs_fs_type);
        kobject_put(config_kobj);
        kmem_cache_destroy(configfs_dir_cachep);
        configfs_dir_cachep = NULL;
        configfs_inode_exit();
}

MODULE_AUTHOR("Oracle");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.0.2");
MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");

module_init(configfs_init);
module_exit(configfs_exit);