path: root/fs/configfs/dir.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dir.c - Operations for configfs directories.
 *
 * 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.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/slab.h>

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

DECLARE_RWSEM(configfs_rename_sem);

static void configfs_d_iput(struct dentry * dentry,
			    struct inode * inode)
{
	struct configfs_dirent * sd = dentry->d_fsdata;

	if (sd) {
		BUG_ON(sd->s_dentry != dentry);
		sd->s_dentry = NULL;
		configfs_put(sd);
	}
	iput(inode);
}

/*
 * We _must_ delete our dentries on last dput, as the chain-to-parent
 * behavior is required to clear the parents of default_groups.
 */
static int configfs_d_delete(struct dentry *dentry)
{
	return 1;
}

static struct dentry_operations configfs_dentry_ops = {
	.d_iput		= configfs_d_iput,
	/* simple_delete_dentry() isn't exported */
	.d_delete	= configfs_d_delete,
};

/*
 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
 */
static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd,
						void * element)
{
	struct configfs_dirent * sd;

	sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL);
	if (!sd)
		return NULL;

	memset(sd, 0, sizeof(*sd));
	atomic_set(&sd->s_count, 1);
	INIT_LIST_HEAD(&sd->s_links);
	INIT_LIST_HEAD(&sd->s_children);
	list_add(&sd->s_sibling, &parent_sd->s_children);
	sd->s_element = element;

	return sd;
}

/*
 *
 * Return -EEXIST if there is already a configfs element with the same
 * name for the same parent.
 *
 * called with parent inode's i_mutex held
 */
int configfs_dirent_exists(struct configfs_dirent *parent_sd,
			   const unsigned char *new)
{
	struct configfs_dirent * sd;

	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
		if (sd->s_element) {
			const unsigned char *existing = configfs_get_name(sd);
			if (strcmp(existing, new))
				continue;
			else
				return -EEXIST;
		}
	}

	return 0;
}


int configfs_make_dirent(struct configfs_dirent * parent_sd,
			 struct dentry * dentry, void * element,
			 umode_t mode, int type)
{
	struct configfs_dirent * sd;

	sd = configfs_new_dirent(parent_sd, element);
	if (!sd)
		return -ENOMEM;

	sd->s_mode = mode;
	sd->s_type = type;
	sd->s_dentry = dentry;
	if (dentry) {
		dentry->d_fsdata = configfs_get(sd