path: root/fs/nilfs2/ioctl.c

/*
 * ioctl.c - NILFS ioctl operations.
 *
 * Copyright (C) 2007, 2008 Nippon Telegraph and Telephone Corporation.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Written by Koji Sato <koji@osrg.net>.
 */

#include <linux/fs.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/capability.h>	/* capable() */
#include <linux/uaccess.h>	/* copy_from_user(), copy_to_user() */
#include <linux/vmalloc.h>
#include <linux/compat.h>	/* compat_ptr() */
#include <linux/mount.h>	/* mnt_want_write_file(), mnt_drop_write_file() */
#include <linux/buffer_head.h>
#include <linux/nilfs2_fs.h>
#include "nilfs.h"
#include "segment.h"
#include "bmap.h"
#include "cpfile.h"
#include "sufile.h"
#include "dat.h"


static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
				 struct nilfs_argv *argv, int dir,
				 ssize_t (*dofunc)(struct the_nilfs *,
						   __u64 *, int,
						   void *, size_t, size_t))
{
	void *buf;
	void __user *base = (void __user *)(unsigned long)argv->v_base;
	size_t maxmembs, total, n;
	ssize_t nr;
	int ret, i;
	__u64 pos, ppos;

	if (argv->v_nmembs == 0)
		return 0;

	if (argv->v_size > PAGE_SIZE)
		return -EINVAL;

	buf = (void *)__get_free_pages(GFP_NOFS, 0);
	if (unlikely(!buf))
		return -ENOMEM;
	maxmembs = PAGE_SIZE / argv->v_size;

	ret = 0;
	total = 0;
	pos = argv->v_index;
	for (i = 0; i < argv->v_nmembs; i += n) {
		n = (argv->v_nmembs - i < maxmembs) ?
			argv->v_nmembs - i : maxmembs;
		if ((dir & _IOC_WRITE) &&
		    copy_from_user(buf, base + argv->v_size * i,
				   argv->v_size * n)) {
			ret = -EFAULT;
			break;
		}
		ppos = pos;
		nr = dofunc(nilfs, &pos, argv->v_flags, buf, argv->v_size,
			       n);
		if (nr < 0) {
			ret = nr;
			break;
		}
		if ((dir & _IOC_READ) &&
		    copy_to_user(base + argv->v_size * i, buf,
				 argv->v_size * nr)) {
			ret = -EFAULT;
			break;
		}
		total += nr;
		if ((size_t)nr < n)
			break;
		if (pos == ppos)
			pos += n;
	}
	argv->v_nmembs = total;

	free_pages((unsigned long)buf, 0);
	return ret;
}

static int nilfs_ioctl_getflags(struct inode *inode, void __user *argp)
{
	unsigned int flags = NILFS_I(inode)->i_flags & FS_FL_USER_VISIBLE;

	return put_user(flags, (int __user *)argp);
}

static int nilfs_ioctl_setflags(struct inode *inode, struct file *filp,
				void __user *argp)
{
	struct nilfs_transaction_info ti;
	unsigned int flags, oldflags;
	int ret;

	if (!inode_owner_or_capable(inode))
		return -EACCES;

	if (get_user(flags, (int __user *)argp))
		return -EFAULT;

	ret = mnt_want_write_file(filp);
	if (ret)
		return ret;

	flags = nilfs_mask_flags(inode->i_mode, flags);

	mutex_lock(&inode->i_mutex);

	oldflags = NILFS_I(inode)->i_flags;

	/*
	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by the
	 * relevant capability.
	 */
	ret = -EPERM;
	if (((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
	    !capable(CAP_LINUX_IMMUTABLE))
		goto out;

	ret = nilfs_transaction_begin(inode->i_sb, &ti, 0);
	if (ret)
		goto out;

	NILFS_I(inode)->i_flags = (oldflags & ~FS_FL_USER_MODIFIABLE) |
		(flags & FS_FL_USER_MODIFIABLE);

	nilfs_set_inode_flags(inode);
	inode->i_ctime = CURRENT_TIME;
	if (IS_SYNC(inode))
		nilfs_set_transaction_flag(NILFS_TI_SYNC);

	nilfs_mark_inode_dirty(inode);
	ret = nilfs_transaction_commit(inode->i_sb);
out:
	mutex_unlock(&inode->i_mutex);
	mnt_drop_write_file(filp);
	return ret;
}

static int nilfs_ioctl_getversion(struct inode *inode, void __user *argp)
{
	return put_user(inode->i_generation, (int __user *)argp);
}

static