lvm2/driver/device-mapper/dmfs-suspend.c

/*
 * dmfs-suspend.c
 *
 * Copyright (C) 2001 Sistina Software
 *
 * This software 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, or (at
 * your option) any later version.
 *
 * This software 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 GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <linux/config.h>
#include <linux/fs.h>

static ssize_t dmfs_suspend_read(struct file *file, char *buf, size_t size, loff_t *pos)
{
	struct inode *inode = file->f_dentry->d_parent->d_inode;
	struct mapped_device *md = (struct mapped_device *)inode->u.generic_ip;

	char content[2] = { '0', '\n' };

	if (size > 2)
		size = 2;

	if (test_bit(DM_ACTIVE, &md->state))
		content[0] = '1';

	if (copy_to_user(buf, content, size))
		return -EFAULT;

	return size;
}

static ssize_t dmfs_suspend_write(struct file *file, const char *buf, size_t size, loff_t *pos)
{
	struct inode *inode = file->f_dentry->d_inode;
	char cmd;

	if (size == 0)
		return 0;

	size = 1;
	if (copy_from_user(&cmd, buf, size))
		return -EFAULT;

	if (cmd != '0' && cmd != '1')
		return -EINVAL;

	/* do suspend or unsuspend */

	return size;
}

static int dmfs_suspend_sync(struct file *file, struct dentry *dentry, int datasync)
{
	return 0;
}

static struct dm_table_file_operations = {
	read:		dmfs_suspend_read,
	write:		dmfs_suspend_write,
	fsync:		dmfs_suspend_sync,
};

static struct dmfs_suspend_inode_operations = {
};

int dmfs_create_suspend(struct inode *dir, int mode)
{
	struct inode *inode = new_inode(dir->i_sb);

	if (inode) {
		inode->i_mode = mode | S_IFREG;
		inode->i_uid = current->fsuid;
		inode->i_gid = current->fsgid;
		inode->i_blksize = PAGE_CACHE_SIZE;
		inode->i_blocks = 0;
		inode->i_rdev = NODEV;
		inode->i_atime = inode->i_ctime = inode->i_mtime = CURRENT_TIME;
		inode->i_fop = &dmfs_suspend_file_operations;
		inode->i_op = &dmfs_suspend_inode_operations;
	}

	return inode;
}