#include <linux/capability.h>

  #include <linux/blkdev.h>

  #include <linux/export.h>

  #include <linux/gfp.h>

  #include <linux/blkpg.h>

  #include <linux/hdreg.h>

  #include <linux/backing-dev.h>

  #include <linux/fs.h>

  #include <linux/blktrace_api.h>

  #include <asm/uaccess.h>
  
  static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  {
  	struct block_device *bdevp;
  	struct gendisk *disk;

  	struct hd_struct *part;

  	struct blkpg_ioctl_arg a;
  	struct blkpg_partition p;

  	struct disk_part_iter piter;

  	long long start, length;

  	int partno;

  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  		return -EFAULT;
  	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  		return -EFAULT;
  	disk = bdev->bd_disk;
  	if (bdev != bdev->bd_contains)
  		return -EINVAL;

  	partno = p.pno;

  	if (partno <= 0)

  		return -EINVAL;
  	switch (a.op) {
  		case BLKPG_ADD_PARTITION:
  			start = p.start >> 9;
  			length = p.length >> 9;
  			/* check for fit in a hd_struct */ 
  			if (sizeof(sector_t) == sizeof(long) && 
  			    sizeof(long long) > sizeof(long)) {
  				long pstart = start, plength = length;
  				if (pstart != start || plength != length
  				    || pstart < 0 || plength < 0)
  					return -EINVAL;
  			}

  			mutex_lock(&bdev->bd_mutex);

  			/* overlap? */

  			disk_part_iter_init(&piter, disk,
  					    DISK_PITER_INCL_EMPTY);
  			while ((part = disk_part_iter_next(&piter))) {
  				if (!(start + length <= part->start_sect ||
  				      start >= part->start_sect + part->nr_sects)) {
  					disk_part_iter_exit(&piter);

  					mutex_unlock(&bdev->bd_mutex);

  					return -EBUSY;
  				}
  			}

  			disk_part_iter_exit(&piter);

  			/* all seems OK */

  			part = add_partition(disk, partno, start, length,

  					     ADDPART_FLAG_NONE, NULL);

  			mutex_unlock(&bdev->bd_mutex);

  			return IS_ERR(part) ? PTR_ERR(part) : 0;

  		case BLKPG_DEL_PARTITION:

  			part = disk_get_part(disk, partno);
  			if (!part)

  				return -ENXIO;

  
  			bdevp = bdget(part_devt(part));
  			disk_put_part(part);

  			if (!bdevp)
  				return -ENOMEM;

  			mutex_lock(&bdevp->bd_mutex);

  			if (bdevp->bd_openers) {

  				mutex_unlock(&bdevp->bd_mutex);

  				bdput(bdevp);
  				return -EBUSY;
  			}
  			/* all seems OK */
  			fsync_bdev(bdevp);

  			invalidate_bdev(bdevp);

  			mutex_lock_nested(&bdev->bd_mutex, 1);

  			delete_partition(disk, partno);

  			mutex_unlock(&bdev->bd_mutex);
  			mutex_unlock(&bdevp->bd_mutex);

  			bdput(bdevp);
  
  			return 0;
  		default:
  			return -EINVAL;
  	}
  }
  
  static int blkdev_reread_part(struct block_device *bdev)
  {
  	struct gendisk *disk = bdev->bd_disk;
  	int res;

  	if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)

  		return -EINVAL;
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;

  	if (!mutex_trylock(&bdev->bd_mutex))

  		return -EBUSY;
  	res = rescan_partitions(disk, bdev);

  	mutex_unlock(&bdev->bd_mutex);

  	return res;
  }

  static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,

  			     uint64_t len, int secure)

  {

  	unsigned long flags = 0;

  	if (start & 511)
  		return -EINVAL;
  	if (len & 511)
  		return -EINVAL;
  	start >>= 9;
  	len >>= 9;

  	if (start + len > (i_size_read(bdev->bd_inode) >> 9))

  		return -EINVAL;

  	if (secure)

  		flags |= BLKDEV_DISCARD_SECURE;

  	return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);

  }

  static int put_ushort(unsigned long arg, unsigned short val)
  {
  	return put_user(val, (unsigned short __user *)arg);
  }
  
  static int put_int(unsigned long arg, int val)
  {
  	return put_user(val, (int __user *)arg);
  }

  static int put_uint(unsigned long arg, unsigned int val)
  {
  	return put_user(val, (unsigned int __user *)arg);
  }

  static int put_long(unsigned long arg, long val)
  {
  	return put_user(val, (long __user *)arg);
  }
  
  static int put_ulong(unsigned long arg, unsigned long val)
  {
  	return put_user(val, (unsigned long __user *)arg);
  }
  
  static int put_u64(unsigned long arg, u64 val)
  {
  	return put_user(val, (u64 __user *)arg);
  }

  int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
  			unsigned cmd, unsigned long arg)
  {
  	struct gendisk *disk = bdev->bd_disk;

  
  	if (disk->fops->ioctl)
  		return disk->fops->ioctl(bdev, mode, cmd, arg);

  	return -ENOTTY;
  }
  /*
   * For the record: _GPL here is only because somebody decided to slap it
   * on the previous export.  Sheer idiocy, since it wasn't copyrightable
   * at all and could be open-coded without any exports by anybody who cares.
   */
  EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);

  /*

   * Is it an unrecognized ioctl? The correct returns are either
   * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
   * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
   * code before returning.
   *
   * Confused drivers sometimes return EINVAL, which is wrong. It
   * means "I understood the ioctl command, but the parameters to
   * it were wrong".
   *
   * We should aim to just fix the broken drivers, the EINVAL case
   * should go away.
   */
  static inline int is_unrecognized_ioctl(int ret)
  {
  	return	ret == -EINVAL ||
  		ret == -ENOTTY ||
  		ret == -ENOIOCTLCMD;
  }
  
  /*

   * always keep this in sync with compat_blkdev_ioctl()

   */

  int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,

  			unsigned long arg)
  {

  	struct gendisk *disk = bdev->bd_disk;

  	struct backing_dev_info *bdi;
  	loff_t size;

  	int ret, n;
  
  	switch(cmd) {

  	case BLKFLSBUF:
  		if (!capable(CAP_SYS_ADMIN))
  			return -EACCES;

  		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);

  		if (!is_unrecognized_ioctl(ret))

  			return ret;

  		fsync_bdev(bdev);

  		invalidate_bdev(bdev);

  		return 0;

  	case BLKROSET:

  		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);

  		if (!is_unrecognized_ioctl(ret))

  			return ret;

  		if (!capable(CAP_SYS_ADMIN))
  			return -EACCES;
  		if (get_user(n, (int __user *)(arg)))
  			return -EFAULT;
  		set_device_ro(bdev, n);
  		return 0;

  	case BLKDISCARD:
  	case BLKSECDISCARD: {

  		uint64_t range[2];

  		if (!(mode & FMODE_WRITE))

  			return -EBADF;
  
  		if (copy_from_user(range, (void __user *)arg, sizeof(range)))
  			return -EFAULT;

  		return blk_ioctl_discard(bdev, range[0], range[1],
  					 cmd == BLKSECDISCARD);

  	}

  	case HDIO_GETGEO: {
  		struct hd_geometry geo;
  
  		if (!arg)
  			return -EINVAL;
  		if (!disk->fops->getgeo)
  			return -ENOTTY;
  
  		/*
  		 * We need to set the startsect first, the driver may
  		 * want to override it.
  		 */

  		memset(&geo, 0, sizeof(geo));

  		geo.start = get_start_sect(bdev);
  		ret = disk->fops->getgeo(bdev, &geo);
  		if (ret)
  			return ret;
  		if (copy_to_user((struct hd_geometry __user *)arg, &geo,
  					sizeof(geo)))
  			return -EFAULT;
  		return 0;
  	}

  	case BLKRAGET:
  	case BLKFRAGET:
  		if (!arg)
  			return -EINVAL;
  		bdi = blk_get_backing_dev_info(bdev);
  		if (bdi == NULL)
  			return -ENOTTY;
  		return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
  	case BLKROGET:
  		return put_int(arg, bdev_read_only(bdev) != 0);

  	case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */

  		return put_int(arg, block_size(bdev));

  	case BLKSSZGET: /* get block device logical block size */

  		return put_int(arg, bdev_logical_block_size(bdev));

  	case BLKPBSZGET: /* get block device physical block size */
  		return put_uint(arg, bdev_physical_block_size(bdev));
  	case BLKIOMIN:
  		return put_uint(arg, bdev_io_min(bdev));
  	case BLKIOOPT:
  		return put_uint(arg, bdev_io_opt(bdev));
  	case BLKALIGNOFF:
  		return put_int(arg, bdev_alignment_offset(bdev));

  	case BLKDISCARDZEROES:
  		return put_uint(arg, bdev_discard_zeroes_data(bdev));

  	case BLKSECTGET:

  		return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));

  	case BLKROTATIONAL:
  		return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));

  	case BLKRASET:
  	case BLKFRASET:
  		if(!capable(CAP_SYS_ADMIN))
  			return -EACCES;
  		bdi = blk_get_backing_dev_info(bdev);
  		if (bdi == NULL)
  			return -ENOTTY;

  		bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;

  		return 0;
  	case BLKBSZSET:
  		/* set the logical block size */
  		if (!capable(CAP_SYS_ADMIN))
  			return -EACCES;
  		if (!arg)
  			return -EINVAL;
  		if (get_user(n, (int __user *) arg))
  			return -EFAULT;

  		if (!(mode & FMODE_EXCL)) {
  			bdgrab(bdev);
  			if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
  				return -EBUSY;
  		}

  		ret = set_blocksize(bdev, n);

  		if (!(mode & FMODE_EXCL))

  			blkdev_put(bdev, mode | FMODE_EXCL);

  		return ret;

  	case BLKPG:

  		ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);

  		break;
  	case BLKRRPART:

  		ret = blkdev_reread_part(bdev);

  		break;
  	case BLKGETSIZE:

  		size = i_size_read(bdev->bd_inode);

  		if ((size >> 9) > ~0UL)
  			return -EFBIG;
  		return put_ulong(arg, size >> 9);
  	case BLKGETSIZE64:

  		return put_u64(arg, i_size_read(bdev->bd_inode));

  	case BLKTRACESTART:
  	case BLKTRACESTOP:
  	case BLKTRACESETUP:
  	case BLKTRACETEARDOWN:

  		ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);

  		break;
  	default:
  		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
  	}
  	return ret;

  }

  EXPORT_SYMBOL_GPL(blkdev_ioctl);