/*
   * Copyright (c) International Business Machines Corp., 2006
   *
   * 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 02111-1307 USA
   *
   * Author: Artem Bityutskiy (Битюцкий Артём)
   */
  
  /*
   * This file includes implementation of UBI character device operations.
   *
   * There are two kinds of character devices in UBI: UBI character devices and
   * UBI volume character devices. UBI character devices allow users to
   * manipulate whole volumes: create, remove, and re-size them. Volume character
   * devices provide volume I/O capabilities.
   *
   * Major and minor numbers are assigned dynamically to both UBI and volume
   * character devices.

   *
   * Well, there is the third kind of character devices - the UBI control
   * character device, which allows to manipulate by UBI devices - create and
   * delete them. In other words, it is used for attaching and detaching MTD
   * devices.

   */
  
  #include <linux/module.h>
  #include <linux/stat.h>

  #include <linux/slab.h>

  #include <linux/ioctl.h>
  #include <linux/capability.h>

  #include <linux/uaccess.h>

  #include <linux/compat.h>

  #include <linux/math64.h>

  #include <mtd/ubi-user.h>

  #include "ubi.h"

  /**

   * get_exclusive - get exclusive access to an UBI volume.
   * @desc: volume descriptor
   *
   * This function changes UBI volume open mode to "exclusive". Returns previous
   * mode value (positive integer) in case of success and a negative error code
   * in case of failure.
   */
  static int get_exclusive(struct ubi_volume_desc *desc)
  {
  	int users, err;
  	struct ubi_volume *vol = desc->vol;
  
  	spin_lock(&vol->ubi->volumes_lock);
  	users = vol->readers + vol->writers + vol->exclusive;
  	ubi_assert(users > 0);
  	if (users > 1) {

  		ubi_err("%d users for volume %d", users, vol->vol_id);

  		err = -EBUSY;
  	} else {
  		vol->readers = vol->writers = 0;
  		vol->exclusive = 1;
  		err = desc->mode;
  		desc->mode = UBI_EXCLUSIVE;
  	}
  	spin_unlock(&vol->ubi->volumes_lock);
  
  	return err;
  }
  
  /**
   * revoke_exclusive - revoke exclusive mode.
   * @desc: volume descriptor
   * @mode: new mode to switch to
   */
  static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
  {
  	struct ubi_volume *vol = desc->vol;
  
  	spin_lock(&vol->ubi->volumes_lock);
  	ubi_assert(vol->readers == 0 && vol->writers == 0);
  	ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
  	vol->exclusive = 0;
  	if (mode == UBI_READONLY)
  		vol->readers = 1;
  	else if (mode == UBI_READWRITE)
  		vol->writers = 1;
  	else
  		vol->exclusive = 1;
  	spin_unlock(&vol->ubi->volumes_lock);
  
  	desc->mode = mode;
  }
  
  static int vol_cdev_open(struct inode *inode, struct file *file)
  {
  	struct ubi_volume_desc *desc;

  	int vol_id = iminor(inode) - 1, mode, ubi_num;
  
  	ubi_num = ubi_major2num(imajor(inode));

  	if (ubi_num < 0)

  		return ubi_num;

  
  	if (file->f_mode & FMODE_WRITE)
  		mode = UBI_READWRITE;
  	else
  		mode = UBI_READONLY;

  	dbg_gen("open device %d, volume %d, mode %d",

  		ubi_num, vol_id, mode);

  	desc = ubi_open_volume(ubi_num, vol_id, mode);

  	if (IS_ERR(desc))
  		return PTR_ERR(desc);
  
  	file->private_data = desc;
  	return 0;
  }
  
  static int vol_cdev_release(struct inode *inode, struct file *file)
  {
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;

  	dbg_gen("release device %d, volume %d, mode %d",
  		vol->ubi->ubi_num, vol->vol_id, desc->mode);

  
  	if (vol->updating) {
  		ubi_warn("update of volume %d not finished, volume is damaged",
  			 vol->vol_id);

  		ubi_assert(!vol->changing_leb);

  		vol->updating = 0;

  		vfree(vol->upd_buf);

  	} else if (vol->changing_leb) {

  		dbg_gen("only %lld of %lld bytes received for atomic LEB change for volume %d:%d, cancel",
  			vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
  			vol->vol_id);

  		vol->changing_leb = 0;
  		vfree(vol->upd_buf);

  	}
  
  	ubi_close_volume(desc);
  	return 0;
  }
  
  static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
  {
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;

  
  	if (vol->updating) {

  		/* Update is in progress, seeking is prohibited */

  		ubi_err("updating");

  		return -EBUSY;
  	}

  	return fixed_size_llseek(file, offset, origin, vol->used_bytes);

  }

  static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
  			  int datasync)

  {
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_device *ubi = desc->vol->ubi;

  	struct inode *inode = file_inode(file);

  	int err;
  	mutex_lock(&inode->i_mutex);
  	err = ubi_sync(ubi->ubi_num);
  	mutex_unlock(&inode->i_mutex);
  	return err;

  }

  static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
  			     loff_t *offp)
  {
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;
  	struct ubi_device *ubi = vol->ubi;

  	int err, lnum, off, len,  tbuf_size;

  	size_t count_save = count;
  	void *tbuf;

  	dbg_gen("read %zd bytes from offset %lld of volume %d",

  		count, *offp, vol->vol_id);

  
  	if (vol->updating) {

  		ubi_err("updating");

  		return -EBUSY;
  	}
  	if (vol->upd_marker) {

  		ubi_err("damaged volume, update marker is set");

  		return -EBADF;
  	}
  	if (*offp == vol->used_bytes || count == 0)
  		return 0;
  
  	if (vol->corrupted)

  		dbg_gen("read from corrupted volume %d", vol->vol_id);

  
  	if (*offp + count > vol->used_bytes)
  		count_save = count = vol->used_bytes - *offp;
  
  	tbuf_size = vol->usable_leb_size;
  	if (count < tbuf_size)
  		tbuf_size = ALIGN(count, ubi->min_io_size);

  	tbuf = vmalloc(tbuf_size);

  	if (!tbuf)
  		return -ENOMEM;
  
  	len = count > tbuf_size ? tbuf_size : count;

  	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);

  
  	do {
  		cond_resched();
  
  		if (off + len >= vol->usable_leb_size)
  			len = vol->usable_leb_size - off;

  		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);

  		if (err)
  			break;
  
  		off += len;
  		if (off == vol->usable_leb_size) {
  			lnum += 1;
  			off -= vol->usable_leb_size;
  		}
  
  		count -= len;
  		*offp += len;
  
  		err = copy_to_user(buf, tbuf, len);
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		buf += len;
  		len = count > tbuf_size ? tbuf_size : count;
  	} while (count);

  	vfree(tbuf);

  	return err ? err : count_save - count;
  }

  /*
   * This function allows to directly write to dynamic UBI volumes, without

   * issuing the volume update operation.

   */
  static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
  				     size_t count, loff_t *offp)
  {
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;
  	struct ubi_device *ubi = vol->ubi;

  	int lnum, off, len, tbuf_size, err = 0;

  	size_t count_save = count;
  	char *tbuf;

  	if (!vol->direct_writes)
  		return -EPERM;

  	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",

  		count, *offp, vol->vol_id);

  
  	if (vol->vol_type == UBI_STATIC_VOLUME)
  		return -EROFS;

  	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);

  	if (off & (ubi->min_io_size - 1)) {

  		ubi_err("unaligned position");

  		return -EINVAL;
  	}
  
  	if (*offp + count > vol->used_bytes)
  		count_save = count = vol->used_bytes - *offp;
  
  	/* We can write only in fractions of the minimum I/O unit */

  	if (count & (ubi->min_io_size - 1)) {

  		ubi_err("unaligned write length");

  		return -EINVAL;
  	}
  
  	tbuf_size = vol->usable_leb_size;
  	if (count < tbuf_size)
  		tbuf_size = ALIGN(count, ubi->min_io_size);

  	tbuf = vmalloc(tbuf_size);

  	if (!tbuf)
  		return -ENOMEM;
  
  	len = count > tbuf_size ? tbuf_size : count;
  
  	while (count) {
  		cond_resched();
  
  		if (off + len >= vol->usable_leb_size)
  			len = vol->usable_leb_size - off;
  
  		err = copy_from_user(tbuf, buf, len);
  		if (err) {
  			err = -EFAULT;
  			break;
  		}

  		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);

  		if (err)
  			break;
  
  		off += len;
  		if (off == vol->usable_leb_size) {
  			lnum += 1;
  			off -= vol->usable_leb_size;
  		}
  
  		count -= len;
  		*offp += len;
  		buf += len;
  		len = count > tbuf_size ? tbuf_size : count;
  	}

  	vfree(tbuf);

  	return err ? err : count_save - count;
  }

  static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
  			      size_t count, loff_t *offp)
  {
  	int err = 0;
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;
  	struct ubi_device *ubi = vol->ubi;

  	if (!vol->updating && !vol->changing_leb)

  		return vol_cdev_direct_write(file, buf, count, offp);

  	if (vol->updating)
  		err = ubi_more_update_data(ubi, vol, buf, count);
  	else
  		err = ubi_more_leb_change_data(ubi, vol, buf, count);

  	if (err < 0) {

  		ubi_err("cannot accept more %zd bytes of data, error %d",

  			count, err);

  		return err;
  	}
  
  	if (err) {
  		/*

  		 * The operation is finished, @err contains number of actually
  		 * written bytes.

  		 */
  		count = err;

  		if (vol->changing_leb) {
  			revoke_exclusive(desc, UBI_READWRITE);
  			return count;
  		}

  		err = ubi_check_volume(ubi, vol->vol_id);
  		if (err < 0)
  			return err;
  
  		if (err) {
  			ubi_warn("volume %d on UBI device %d is corrupted",
  				 vol->vol_id, ubi->ubi_num);
  			vol->corrupted = 1;
  		}
  		vol->checked = 1;

  		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);

  		revoke_exclusive(desc, UBI_READWRITE);
  	}

  	return count;
  }

  static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
  			   unsigned long arg)

  {
  	int err = 0;
  	struct ubi_volume_desc *desc = file->private_data;
  	struct ubi_volume *vol = desc->vol;
  	struct ubi_device *ubi = vol->ubi;
  	void __user *argp = (void __user *)arg;

  	switch (cmd) {

  	/* Volume update command */
  	case UBI_IOCVOLUP:
  	{
  		int64_t bytes, rsvd_bytes;
  
  		if (!capable(CAP_SYS_RESOURCE)) {
  			err = -EPERM;
  			break;
  		}
  
  		err = copy_from_user(&bytes, argp, sizeof(int64_t));
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		if (desc->mode == UBI_READONLY) {
  			err = -EROFS;
  			break;
  		}

  		rsvd_bytes = (long long)vol->reserved_pebs *
  					ubi->leb_size-vol->data_pad;

  		if (bytes < 0 || bytes > rsvd_bytes) {
  			err = -EINVAL;
  			break;
  		}
  
  		err = get_exclusive(desc);
  		if (err < 0)
  			break;

  		err = ubi_start_update(ubi, vol, bytes);

  		if (bytes == 0) {
  			ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);

  			revoke_exclusive(desc, UBI_READWRITE);

  		}

  		break;
  	}

  	/* Atomic logical eraseblock change command */
  	case UBI_IOCEBCH:
  	{
  		struct ubi_leb_change_req req;
  
  		err = copy_from_user(&req, argp,
  				     sizeof(struct ubi_leb_change_req));
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		if (desc->mode == UBI_READONLY ||
  		    vol->vol_type == UBI_STATIC_VOLUME) {
  			err = -EROFS;
  			break;
  		}
  
  		/* Validate the request */
  		err = -EINVAL;
  		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
  		    req.bytes < 0 || req.lnum >= vol->usable_leb_size)
  			break;

  
  		err = get_exclusive(desc);
  		if (err < 0)
  			break;
  
  		err = ubi_start_leb_change(ubi, vol, &req);
  		if (req.bytes == 0)
  			revoke_exclusive(desc, UBI_READWRITE);
  		break;
  	}

  	/* Logical eraseblock erasure command */
  	case UBI_IOCEBER:
  	{
  		int32_t lnum;

  		err = get_user(lnum, (__user int32_t *)argp);

  		if (err) {
  			err = -EFAULT;
  			break;
  		}

  		if (desc->mode == UBI_READONLY ||
  		    vol->vol_type == UBI_STATIC_VOLUME) {

  			err = -EROFS;
  			break;
  		}
  
  		if (lnum < 0 || lnum >= vol->reserved_pebs) {
  			err = -EINVAL;
  			break;
  		}

  		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);

  		err = ubi_eba_unmap_leb(ubi, vol, lnum);

  		if (err)
  			break;

  		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);

  		break;
  	}

  
  	/* Logical eraseblock map command */
  	case UBI_IOCEBMAP:
  	{
  		struct ubi_map_req req;
  
  		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
  		if (err) {
  			err = -EFAULT;
  			break;
  		}

  		err = ubi_leb_map(desc, req.lnum);

  		break;
  	}

  
  	/* Logical eraseblock un-map command */
  	case UBI_IOCEBUNMAP:
  	{
  		int32_t lnum;
  
  		err = get_user(lnum, (__user int32_t *)argp);
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  		err = ubi_leb_unmap(desc, lnum);
  		break;
  	}

  
  	/* Check if logical eraseblock is mapped command */
  	case UBI_IOCEBISMAP:
  	{
  		int32_t lnum;
  
  		err = get_user(lnum, (__user int32_t *)argp);
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  		err = ubi_is_mapped(desc, lnum);
  		break;
  	}

  	/* Set volume property command */

  	case UBI_IOCSETVOLPROP:

  	{

  		struct ubi_set_vol_prop_req req;

  
  		err = copy_from_user(&req, argp,

  				     sizeof(struct ubi_set_vol_prop_req));

  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  		switch (req.property) {

  		case UBI_VOL_PROP_DIRECT_WRITE:

  			mutex_lock(&ubi->device_mutex);

  			desc->vol->direct_writes = !!req.value;

  			mutex_unlock(&ubi->device_mutex);

  			break;
  		default:
  			err = -EINVAL;
  			break;
  		}
  		break;
  	}

  	/* Create a R/O block device on top of the UBI volume */
  	case UBI_IOCVOLCRBLK:

  	{
  		struct ubi_volume_info vi;
  
  		ubi_get_volume_info(desc, &vi);

  		err = ubiblock_create(&vi);

  		break;
  	}

  	/* Remove the R/O block device */
  	case UBI_IOCVOLRMBLK:

  	{
  		struct ubi_volume_info vi;
  
  		ubi_get_volume_info(desc, &vi);

  		err = ubiblock_remove(&vi);

  		break;
  	}

  	default:
  		err = -ENOTTY;
  		break;
  	}

  	return err;
  }
  
  /**
   * verify_mkvol_req - verify volume creation request.
   * @ubi: UBI device description object
   * @req: the request to check
   *
   * This function zero if the request is correct, and %-EINVAL if not.
   */
  static int verify_mkvol_req(const struct ubi_device *ubi,
  			    const struct ubi_mkvol_req *req)
  {
  	int n, err = -EINVAL;
  
  	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
  	    req->name_len < 0)
  		goto bad;
  
  	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
  	    req->vol_id != UBI_VOL_NUM_AUTO)
  		goto bad;
  
  	if (req->alignment == 0)
  		goto bad;
  
  	if (req->bytes == 0)
  		goto bad;
  
  	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
  	    req->vol_type != UBI_STATIC_VOLUME)
  		goto bad;
  
  	if (req->alignment > ubi->leb_size)
  		goto bad;

  	n = req->alignment & (ubi->min_io_size - 1);

  	if (req->alignment != 1 && n)
  		goto bad;

  	if (!req->name[0] || !req->name_len)
  		goto bad;

  	if (req->name_len > UBI_VOL_NAME_MAX) {
  		err = -ENAMETOOLONG;
  		goto bad;
  	}

  	n = strnlen(req->name, req->name_len + 1);
  	if (n != req->name_len)
  		goto bad;

  	return 0;
  
  bad:

  	ubi_err("bad volume creation request");

  	ubi_dump_mkvol_req(req);

  	return err;
  }
  
  /**
   * verify_rsvol_req - verify volume re-size request.
   * @ubi: UBI device description object
   * @req: the request to check
   *
   * This function returns zero if the request is correct, and %-EINVAL if not.
   */
  static int verify_rsvol_req(const struct ubi_device *ubi,
  			    const struct ubi_rsvol_req *req)
  {
  	if (req->bytes <= 0)
  		return -EINVAL;
  
  	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
  		return -EINVAL;
  
  	return 0;
  }

  /**
   * rename_volumes - rename UBI volumes.
   * @ubi: UBI device description object
   * @req: volumes re-name request
   *
   * This is a helper function for the volume re-name IOCTL which validates the
   * the request, opens the volume and calls corresponding volumes management
   * function. Returns zero in case of success and a negative error code in case
   * of failure.
   */
  static int rename_volumes(struct ubi_device *ubi,
  			  struct ubi_rnvol_req *req)
  {
  	int i, n, err;
  	struct list_head rename_list;
  	struct ubi_rename_entry *re, *re1;
  
  	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
  		return -EINVAL;
  
  	if (req->count == 0)
  		return 0;
  
  	/* Validate volume IDs and names in the request */
  	for (i = 0; i < req->count; i++) {
  		if (req->ents[i].vol_id < 0 ||
  		    req->ents[i].vol_id >= ubi->vtbl_slots)
  			return -EINVAL;
  		if (req->ents[i].name_len < 0)
  			return -EINVAL;
  		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
  			return -ENAMETOOLONG;
  		req->ents[i].name[req->ents[i].name_len] = '\0';
  		n = strlen(req->ents[i].name);
  		if (n != req->ents[i].name_len)

  			return -EINVAL;

  	}
  
  	/* Make sure volume IDs and names are unique */
  	for (i = 0; i < req->count - 1; i++) {
  		for (n = i + 1; n < req->count; n++) {
  			if (req->ents[i].vol_id == req->ents[n].vol_id) {

  				ubi_err("duplicated volume id %d",

  					req->ents[i].vol_id);
  				return -EINVAL;
  			}
  			if (!strcmp(req->ents[i].name, req->ents[n].name)) {

  				ubi_err("duplicated volume name \"%s\"",

  					req->ents[i].name);
  				return -EINVAL;
  			}
  		}
  	}
  
  	/* Create the re-name list */
  	INIT_LIST_HEAD(&rename_list);
  	for (i = 0; i < req->count; i++) {
  		int vol_id = req->ents[i].vol_id;
  		int name_len = req->ents[i].name_len;
  		const char *name = req->ents[i].name;
  
  		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
  		if (!re) {
  			err = -ENOMEM;
  			goto out_free;
  		}

  		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_READWRITE);

  		if (IS_ERR(re->desc)) {
  			err = PTR_ERR(re->desc);

  			ubi_err("cannot open volume %d, error %d", vol_id, err);

  			kfree(re);
  			goto out_free;
  		}
  
  		/* Skip this re-naming if the name does not really change */
  		if (re->desc->vol->name_len == name_len &&
  		    !memcmp(re->desc->vol->name, name, name_len)) {
  			ubi_close_volume(re->desc);
  			kfree(re);
  			continue;
  		}
  
  		re->new_name_len = name_len;
  		memcpy(re->new_name, name, name_len);
  		list_add_tail(&re->list, &rename_list);

  		dbg_gen("will rename volume %d from \"%s\" to \"%s\"",

  			vol_id, re->desc->vol->name, name);
  	}
  
  	if (list_empty(&rename_list))
  		return 0;
  
  	/* Find out the volumes which have to be removed */
  	list_for_each_entry(re, &rename_list, list) {
  		struct ubi_volume_desc *desc;
  		int no_remove_needed = 0;
  
  		/*
  		 * Volume @re->vol_id is going to be re-named to
  		 * @re->new_name, while its current name is @name. If a volume
  		 * with name @re->new_name currently exists, it has to be
  		 * removed, unless it is also re-named in the request (@req).
  		 */
  		list_for_each_entry(re1, &rename_list, list) {
  			if (re->new_name_len == re1->desc->vol->name_len &&
  			    !memcmp(re->new_name, re1->desc->vol->name,
  				    re1->desc->vol->name_len)) {
  				no_remove_needed = 1;
  				break;
  			}
  		}
  
  		if (no_remove_needed)
  			continue;
  
  		/*
  		 * It seems we need to remove volume with name @re->new_name,
  		 * if it exists.
  		 */

  		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
  					  UBI_EXCLUSIVE);

  		if (IS_ERR(desc)) {
  			err = PTR_ERR(desc);
  			if (err == -ENODEV)
  				/* Re-naming into a non-existing volume name */
  				continue;
  
  			/* The volume exists but busy, or an error occurred */

  			ubi_err("cannot open volume \"%s\", error %d",

  				re->new_name, err);
  			goto out_free;
  		}

  		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
  		if (!re1) {

  			err = -ENOMEM;
  			ubi_close_volume(desc);
  			goto out_free;
  		}

  		re1->remove = 1;
  		re1->desc = desc;
  		list_add(&re1->list, &rename_list);

  		dbg_gen("will remove volume %d, name \"%s\"",

  			re1->desc->vol->vol_id, re1->desc->vol->name);

  	}

  	mutex_lock(&ubi->device_mutex);

  	err = ubi_rename_volumes(ubi, &rename_list);

  	mutex_unlock(&ubi->device_mutex);

  
  out_free:
  	list_for_each_entry_safe(re, re1, &rename_list, list) {
  		ubi_close_volume(re->desc);
  		list_del(&re->list);
  		kfree(re);
  	}
  	return err;
  }

  static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
  			   unsigned long arg)

  {
  	int err = 0;
  	struct ubi_device *ubi;
  	struct ubi_volume_desc *desc;
  	void __user *argp = (void __user *)arg;

  	if (!capable(CAP_SYS_RESOURCE))
  		return -EPERM;

  	ubi = ubi_get_by_major(imajor(file->f_mapping->host));

  	if (!ubi)
  		return -ENODEV;

  
  	switch (cmd) {
  	/* Create volume command */
  	case UBI_IOCMKVOL:
  	{
  		struct ubi_mkvol_req req;

  		dbg_gen("create volume");

  		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));

  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		err = verify_mkvol_req(ubi, &req);
  		if (err)
  			break;

  		mutex_lock(&ubi->device_mutex);

  		err = ubi_create_volume(ubi, &req);

  		mutex_unlock(&ubi->device_mutex);

  		if (err)
  			break;

  		err = put_user(req.vol_id, (__user int32_t *)argp);

  		if (err)
  			err = -EFAULT;
  
  		break;
  	}
  
  	/* Remove volume command */
  	case UBI_IOCRMVOL:
  	{
  		int vol_id;

  		dbg_gen("remove volume");

  		err = get_user(vol_id, (__user int32_t *)argp);

  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
  		if (IS_ERR(desc)) {
  			err = PTR_ERR(desc);
  			break;
  		}

  		mutex_lock(&ubi->device_mutex);

  		err = ubi_remove_volume(desc, 0);

  		mutex_unlock(&ubi->device_mutex);

  		/*

  		 * The volume is deleted (unless an error occurred), and the
  		 * 'struct ubi_volume' object will be freed when
  		 * 'ubi_close_volume()' will call 'put_device()'.

  		 */
  		ubi_close_volume(desc);

  		break;
  	}
  
  	/* Re-size volume command */
  	case UBI_IOCRSVOL:
  	{
  		int pebs;

  		struct ubi_rsvol_req req;

  		dbg_gen("re-size volume");

  		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));

  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		err = verify_rsvol_req(ubi, &req);
  		if (err)
  			break;
  
  		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
  		if (IS_ERR(desc)) {
  			err = PTR_ERR(desc);
  			break;
  		}

  		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
  			       desc->vol->usable_leb_size);

  		mutex_lock(&ubi->device_mutex);

  		err = ubi_resize_volume(desc, pebs);

  		mutex_unlock(&ubi->device_mutex);

  		ubi_close_volume(desc);
  		break;
  	}

  	/* Re-name volumes command */
  	case UBI_IOCRNVOL:
  	{
  		struct ubi_rnvol_req *req;

  		dbg_gen("re-name volumes");

  		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
  		if (!req) {
  			err = -ENOMEM;
  			break;
  		};
  
  		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
  		if (err) {
  			err = -EFAULT;
  			kfree(req);
  			break;
  		}

  		err = rename_volumes(ubi, req);

  		kfree(req);
  		break;
  	}

  	default:
  		err = -ENOTTY;
  		break;
  	}

  	ubi_put_device(ubi);

  	return err;
  }

  static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
  			    unsigned long arg)

  {
  	int err = 0;
  	void __user *argp = (void __user *)arg;
  
  	if (!capable(CAP_SYS_RESOURCE))
  		return -EPERM;
  
  	switch (cmd) {
  	/* Attach an MTD device command */
  	case UBI_IOCATT:
  	{
  		struct ubi_attach_req req;
  		struct mtd_info *mtd;

  		dbg_gen("attach MTD device");

  		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		if (req.mtd_num < 0 ||
  		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
  			err = -EINVAL;
  			break;
  		}
  
  		mtd = get_mtd_device(NULL, req.mtd_num);
  		if (IS_ERR(mtd)) {
  			err = PTR_ERR(mtd);
  			break;
  		}
  
  		/*
  		 * Note, further request verification is done by
  		 * 'ubi_attach_mtd_dev()'.
  		 */
  		mutex_lock(&ubi_devices_mutex);

  		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,

  					 req.max_beb_per1024);

  		mutex_unlock(&ubi_devices_mutex);
  		if (err < 0)
  			put_mtd_device(mtd);
  		else
  			/* @err contains UBI device number */
  			err = put_user(err, (__user int32_t *)argp);
  
  		break;
  	}
  
  	/* Detach an MTD device command */
  	case UBI_IOCDET:
  	{
  		int ubi_num;

  		dbg_gen("detach MTD device");

  		err = get_user(ubi_num, (__user int32_t *)argp);
  		if (err) {
  			err = -EFAULT;
  			break;
  		}
  
  		mutex_lock(&ubi_devices_mutex);
  		err = ubi_detach_mtd_dev(ubi_num, 0);
  		mutex_unlock(&ubi_devices_mutex);
  		break;
  	}
  
  	default:
  		err = -ENOTTY;
  		break;
  	}
  
  	return err;
  }

  #ifdef CONFIG_COMPAT
  static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
  				  unsigned long arg)
  {
  	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
  
  	return vol_cdev_ioctl(file, cmd, translated_arg);
  }
  
  static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
  				  unsigned long arg)
  {
  	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
  
  	return ubi_cdev_ioctl(file, cmd, translated_arg);
  }
  
  static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
  				   unsigned long arg)
  {
  	unsigned long translated_arg = (unsigned long)compat_ptr(arg);
  
  	return ctrl_cdev_ioctl(file, cmd, translated_arg);
  }
  #else
  #define vol_cdev_compat_ioctl  NULL
  #define ubi_cdev_compat_ioctl  NULL
  #define ctrl_cdev_compat_ioctl NULL
  #endif
  
  /* UBI volume character device operations */
  const struct file_operations ubi_vol_cdev_operations = {
  	.owner          = THIS_MODULE,
  	.open           = vol_cdev_open,
  	.release        = vol_cdev_release,
  	.llseek         = vol_cdev_llseek,
  	.read           = vol_cdev_read,
  	.write          = vol_cdev_write,

  	.fsync		= vol_cdev_fsync,

  	.unlocked_ioctl = vol_cdev_ioctl,
  	.compat_ioctl   = vol_cdev_compat_ioctl,

  };

  /* UBI character device operations */

  const struct file_operations ubi_cdev_operations = {

  	.owner          = THIS_MODULE,
  	.llseek         = no_llseek,
  	.unlocked_ioctl = ubi_cdev_ioctl,
  	.compat_ioctl   = ubi_cdev_compat_ioctl,

  };

  /* UBI control character device operations */
  const struct file_operations ubi_ctrl_cdev_operations = {
  	.owner          = THIS_MODULE,
  	.unlocked_ioctl = ctrl_cdev_ioctl,
  	.compat_ioctl   = ctrl_cdev_compat_ioctl,

  	.llseek		= no_llseek,

  };