[linux-2.6-block.git] / fs / configfs / mount.c

/* -*- 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/slab.h>

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

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

static struct vfsmount *configfs_mount = 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_SIZE;
	sb->s_blocksize_bits = PAGE_SHIFT;
	sb->s_magic = CONFIGFS_MAGIC;
	sb->s_op = &configfs_ops;
	sb->s_time_gran = 1;

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

	root = d_make_root(inode);
	if (!root) {
		pr_debug("%s: could not get root dentry!\n",__func__);
		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;
	sb->s_d_op = &configfs_dentry_ops; /* the rest get that */
	return 0;
}

static struct dentry *configfs_do_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_single(fs_type, flags, data, configfs_fill_super);
}

static struct file_system_type configfs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "configfs",
	.mount		= configfs_do_mount,
	.kill_sb	= kill_litter_super,
};
MODULE_ALIAS_FS("configfs");

struct dentry *configfs_pin_fs(void)
{
	int err = simple_pin_fs(&configfs_fs_type, &configfs_mount,
			     &configfs_mnt_count);
	return err ? ERR_PTR(err) : configfs_mount->mnt_root;
}

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


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;

	err = sysfs_create_mount_point(kernel_kobj, "config");
	if (err)
		goto out2;

	err = register_filesystem(&configfs_fs_type);
	if (err)
		goto out3;

	return 0;
out3:
	pr_err("Unable to register filesystem!\n");
	sysfs_remove_mount_point(kernel_kobj, "config");
out2:
	kmem_cache_destroy(configfs_dir_cachep);
	configfs_dir_cachep = NULL;
out:
	return err;
}

static void __exit configfs_exit(void)
{
	unregister_filesystem(&configfs_fs_type);
	sysfs_remove_mount_point(kernel_kobj, "config");
	kmem_cache_destroy(configfs_dir_cachep);
	configfs_dir_cachep = NULL;
}

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

core_initcall(configfs_init);
module_exit(configfs_exit);
Commit	Line	Data
	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	static struct vfsmount *configfs_mount = NULL;
	41	struct kmem_cache *configfs_dir_cachep;
	42	static int configfs_mnt_count = 0;
	43
	44	static const struct super_operations configfs_ops = {
	45	.statfs = simple_statfs,
	46	.drop_inode = generic_delete_inode,
	47	};
	48
	49	static 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
	56	int configfs_is_root(struct config_item *item)
	57	{
	58	return item == &configfs_root_group.cg_item;
	59	}
	60
	61	static 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
	69	static 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_SIZE;
	75	sb->s_blocksize_bits = PAGE_SHIFT;
	76	sb->s_magic = CONFIGFS_MAGIC;
	77	sb->s_op = &configfs_ops;
	78	sb->s_time_gran = 1;
	79
	80	inode = configfs_new_inode(S_IFDIR \| S_IRWXU \| S_IRUGO \| S_IXUGO,
	81	&configfs_root, sb);
	82	if (inode) {
	83	inode->i_op = &configfs_root_inode_operations;
	84	inode->i_fop = &configfs_dir_operations;
	85	/* directory inodes start off with i_nlink == 2 (for "." entry) */
	86	inc_nlink(inode);
	87	} else {
	88	pr_debug("could not get root inode\n");
	89	return -ENOMEM;
	90	}
	91
	92	root = d_make_root(inode);
	93	if (!root) {
	94	pr_debug("%s: could not get root dentry!\n",__func__);
	95	return -ENOMEM;
	96	}
	97	config_group_init(&configfs_root_group);
	98	configfs_root_group.cg_item.ci_dentry = root;
	99	root->d_fsdata = &configfs_root;
	100	sb->s_root = root;
	101	sb->s_d_op = &configfs_dentry_ops; /* the rest get that */
	102	return 0;
	103	}
	104
	105	static struct dentry configfs_do_mount(struct file_system_type fs_type,
	106	int flags, const char dev_name, void data)
	107	{
	108	return mount_single(fs_type, flags, data, configfs_fill_super);
	109	}
	110
	111	static struct file_system_type configfs_fs_type = {
	112	.owner = THIS_MODULE,
	113	.name = "configfs",
	114	.mount = configfs_do_mount,
	115	.kill_sb = kill_litter_super,
	116	};
	117	MODULE_ALIAS_FS("configfs");
	118
	119	struct dentry *configfs_pin_fs(void)
	120	{
	121	int err = simple_pin_fs(&configfs_fs_type, &configfs_mount,
	122	&configfs_mnt_count);
	123	return err ? ERR_PTR(err) : configfs_mount->mnt_root;
	124	}
	125
	126	void configfs_release_fs(void)
	127	{
	128	simple_release_fs(&configfs_mount, &configfs_mnt_count);
	129	}
	130
	131
	132	static int __init configfs_init(void)
	133	{
	134	int err = -ENOMEM;
	135
	136	configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
	137	sizeof(struct configfs_dirent),
	138	0, 0, NULL);
	139	if (!configfs_dir_cachep)
	140	goto out;
	141
	142	err = sysfs_create_mount_point(kernel_kobj, "config");
	143	if (err)
	144	goto out2;
	145
	146	err = register_filesystem(&configfs_fs_type);
	147	if (err)
	148	goto out3;
	149
	150	return 0;
	151	out3:
	152	pr_err("Unable to register filesystem!\n");
	153	sysfs_remove_mount_point(kernel_kobj, "config");
	154	out2:
	155	kmem_cache_destroy(configfs_dir_cachep);
	156	configfs_dir_cachep = NULL;
	157	out:
	158	return err;
	159	}
	160
	161	static void __exit configfs_exit(void)
	162	{
	163	unregister_filesystem(&configfs_fs_type);
	164	sysfs_remove_mount_point(kernel_kobj, "config");
	165	kmem_cache_destroy(configfs_dir_cachep);
	166	configfs_dir_cachep = NULL;
	167	}
	168
	169	MODULE_AUTHOR("Oracle");
	170	MODULE_LICENSE("GPL");
	171	MODULE_VERSION("0.0.2");
	172	MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
	173
	174	core_initcall(configfs_init);
	175	module_exit(configfs_exit);