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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Martin K. Petersen](/assets/img/avatar_default.png)
blkdev_issue_discard() will zero a given block range. This is done by way of explicit writing, thus provisioning or allocating the blocks on disk. There are use cases where the desired behavior is to zero the blocks but unprovision them if possible. The blocks must deterministically contain zeroes when they are subsequently read back. This patch adds a flag to blkdev_issue_zeroout() that provides this variant. If the discard flag is set and a block device guarantees discard_zeroes_data we will use REQ_DISCARD to clear the block range. If the device does not support discard_zeroes_data or if the discard request fails we will fall back to first REQ_WRITE_SAME and then a regular REQ_WRITE. Also update the callers of blkdev_issue_zero() to reflect the new flag and make sb_issue_zeroout() prefer the discard approach. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
430 lines
11 KiB
C
430 lines
11 KiB
C
#include <linux/capability.h>
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#include <linux/blkdev.h>
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#include <linux/export.h>
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#include <linux/gfp.h>
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#include <linux/blkpg.h>
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#include <linux/hdreg.h>
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#include <linux/backing-dev.h>
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#include <linux/fs.h>
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#include <linux/blktrace_api.h>
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#include <asm/uaccess.h>
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static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
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{
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struct block_device *bdevp;
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struct gendisk *disk;
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struct hd_struct *part, *lpart;
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struct blkpg_ioctl_arg a;
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struct blkpg_partition p;
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struct disk_part_iter piter;
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long long start, length;
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int partno;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
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return -EFAULT;
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if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
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return -EFAULT;
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disk = bdev->bd_disk;
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if (bdev != bdev->bd_contains)
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return -EINVAL;
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partno = p.pno;
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if (partno <= 0)
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return -EINVAL;
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switch (a.op) {
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case BLKPG_ADD_PARTITION:
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start = p.start >> 9;
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length = p.length >> 9;
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/* check for fit in a hd_struct */
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if (sizeof(sector_t) == sizeof(long) &&
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sizeof(long long) > sizeof(long)) {
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long pstart = start, plength = length;
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if (pstart != start || plength != length
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|| pstart < 0 || plength < 0 || partno > 65535)
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return -EINVAL;
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}
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mutex_lock(&bdev->bd_mutex);
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/* overlap? */
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disk_part_iter_init(&piter, disk,
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DISK_PITER_INCL_EMPTY);
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while ((part = disk_part_iter_next(&piter))) {
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if (!(start + length <= part->start_sect ||
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start >= part->start_sect + part->nr_sects)) {
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disk_part_iter_exit(&piter);
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mutex_unlock(&bdev->bd_mutex);
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return -EBUSY;
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}
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}
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disk_part_iter_exit(&piter);
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/* all seems OK */
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part = add_partition(disk, partno, start, length,
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ADDPART_FLAG_NONE, NULL);
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mutex_unlock(&bdev->bd_mutex);
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return PTR_ERR_OR_ZERO(part);
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case BLKPG_DEL_PARTITION:
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part = disk_get_part(disk, partno);
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if (!part)
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return -ENXIO;
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bdevp = bdget(part_devt(part));
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disk_put_part(part);
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if (!bdevp)
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return -ENOMEM;
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mutex_lock(&bdevp->bd_mutex);
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if (bdevp->bd_openers) {
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mutex_unlock(&bdevp->bd_mutex);
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bdput(bdevp);
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return -EBUSY;
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}
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/* all seems OK */
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fsync_bdev(bdevp);
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invalidate_bdev(bdevp);
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mutex_lock_nested(&bdev->bd_mutex, 1);
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delete_partition(disk, partno);
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mutex_unlock(&bdev->bd_mutex);
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mutex_unlock(&bdevp->bd_mutex);
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bdput(bdevp);
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return 0;
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case BLKPG_RESIZE_PARTITION:
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start = p.start >> 9;
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/* new length of partition in bytes */
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length = p.length >> 9;
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/* check for fit in a hd_struct */
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if (sizeof(sector_t) == sizeof(long) &&
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sizeof(long long) > sizeof(long)) {
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long pstart = start, plength = length;
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if (pstart != start || plength != length
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|| pstart < 0 || plength < 0)
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return -EINVAL;
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}
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part = disk_get_part(disk, partno);
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if (!part)
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return -ENXIO;
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bdevp = bdget(part_devt(part));
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if (!bdevp) {
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disk_put_part(part);
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return -ENOMEM;
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}
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mutex_lock(&bdevp->bd_mutex);
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mutex_lock_nested(&bdev->bd_mutex, 1);
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if (start != part->start_sect) {
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mutex_unlock(&bdevp->bd_mutex);
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mutex_unlock(&bdev->bd_mutex);
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bdput(bdevp);
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disk_put_part(part);
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return -EINVAL;
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}
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/* overlap? */
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disk_part_iter_init(&piter, disk,
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DISK_PITER_INCL_EMPTY);
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while ((lpart = disk_part_iter_next(&piter))) {
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if (lpart->partno != partno &&
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!(start + length <= lpart->start_sect ||
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start >= lpart->start_sect + lpart->nr_sects)
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) {
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disk_part_iter_exit(&piter);
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mutex_unlock(&bdevp->bd_mutex);
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mutex_unlock(&bdev->bd_mutex);
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bdput(bdevp);
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disk_put_part(part);
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return -EBUSY;
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}
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}
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disk_part_iter_exit(&piter);
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part_nr_sects_write(part, (sector_t)length);
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i_size_write(bdevp->bd_inode, p.length);
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mutex_unlock(&bdevp->bd_mutex);
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mutex_unlock(&bdev->bd_mutex);
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bdput(bdevp);
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disk_put_part(part);
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return 0;
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default:
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return -EINVAL;
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}
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}
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static int blkdev_reread_part(struct block_device *bdev)
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{
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struct gendisk *disk = bdev->bd_disk;
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int res;
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if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
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return -EINVAL;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (!mutex_trylock(&bdev->bd_mutex))
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return -EBUSY;
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res = rescan_partitions(disk, bdev);
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mutex_unlock(&bdev->bd_mutex);
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return res;
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}
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static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
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uint64_t len, int secure)
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{
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unsigned long flags = 0;
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if (start & 511)
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return -EINVAL;
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if (len & 511)
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return -EINVAL;
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start >>= 9;
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len >>= 9;
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if (start + len > (i_size_read(bdev->bd_inode) >> 9))
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return -EINVAL;
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if (secure)
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flags |= BLKDEV_DISCARD_SECURE;
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return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
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}
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static int blk_ioctl_zeroout(struct block_device *bdev, uint64_t start,
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uint64_t len)
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{
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if (start & 511)
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return -EINVAL;
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if (len & 511)
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return -EINVAL;
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start >>= 9;
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len >>= 9;
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if (start + len > (i_size_read(bdev->bd_inode) >> 9))
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return -EINVAL;
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return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
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}
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static int put_ushort(unsigned long arg, unsigned short val)
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{
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return put_user(val, (unsigned short __user *)arg);
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}
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static int put_int(unsigned long arg, int val)
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{
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return put_user(val, (int __user *)arg);
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}
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static int put_uint(unsigned long arg, unsigned int val)
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{
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return put_user(val, (unsigned int __user *)arg);
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}
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static int put_long(unsigned long arg, long val)
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{
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return put_user(val, (long __user *)arg);
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}
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static int put_ulong(unsigned long arg, unsigned long val)
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{
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return put_user(val, (unsigned long __user *)arg);
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}
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static int put_u64(unsigned long arg, u64 val)
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{
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return put_user(val, (u64 __user *)arg);
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}
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int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
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unsigned cmd, unsigned long arg)
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{
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struct gendisk *disk = bdev->bd_disk;
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if (disk->fops->ioctl)
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return disk->fops->ioctl(bdev, mode, cmd, arg);
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return -ENOTTY;
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}
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/*
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* For the record: _GPL here is only because somebody decided to slap it
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* on the previous export. Sheer idiocy, since it wasn't copyrightable
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* at all and could be open-coded without any exports by anybody who cares.
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*/
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EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
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/*
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* Is it an unrecognized ioctl? The correct returns are either
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* ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
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* fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
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* code before returning.
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*
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* Confused drivers sometimes return EINVAL, which is wrong. It
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* means "I understood the ioctl command, but the parameters to
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* it were wrong".
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*
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* We should aim to just fix the broken drivers, the EINVAL case
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* should go away.
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*/
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static inline int is_unrecognized_ioctl(int ret)
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{
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return ret == -EINVAL ||
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ret == -ENOTTY ||
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ret == -ENOIOCTLCMD;
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}
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/*
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* always keep this in sync with compat_blkdev_ioctl()
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*/
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int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
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unsigned long arg)
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{
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struct gendisk *disk = bdev->bd_disk;
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struct backing_dev_info *bdi;
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loff_t size;
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int ret, n;
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unsigned int max_sectors;
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switch(cmd) {
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case BLKFLSBUF:
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
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if (!is_unrecognized_ioctl(ret))
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return ret;
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fsync_bdev(bdev);
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invalidate_bdev(bdev);
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return 0;
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case BLKROSET:
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ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
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if (!is_unrecognized_ioctl(ret))
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return ret;
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (get_user(n, (int __user *)(arg)))
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return -EFAULT;
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set_device_ro(bdev, n);
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return 0;
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case BLKDISCARD:
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case BLKSECDISCARD: {
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uint64_t range[2];
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if (!(mode & FMODE_WRITE))
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return -EBADF;
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if (copy_from_user(range, (void __user *)arg, sizeof(range)))
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return -EFAULT;
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return blk_ioctl_discard(bdev, range[0], range[1],
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cmd == BLKSECDISCARD);
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}
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case BLKZEROOUT: {
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uint64_t range[2];
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if (!(mode & FMODE_WRITE))
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return -EBADF;
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if (copy_from_user(range, (void __user *)arg, sizeof(range)))
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return -EFAULT;
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return blk_ioctl_zeroout(bdev, range[0], range[1]);
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}
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case HDIO_GETGEO: {
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struct hd_geometry geo;
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if (!arg)
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return -EINVAL;
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if (!disk->fops->getgeo)
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return -ENOTTY;
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/*
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* We need to set the startsect first, the driver may
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* want to override it.
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*/
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memset(&geo, 0, sizeof(geo));
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geo.start = get_start_sect(bdev);
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ret = disk->fops->getgeo(bdev, &geo);
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if (ret)
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return ret;
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if (copy_to_user((struct hd_geometry __user *)arg, &geo,
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sizeof(geo)))
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return -EFAULT;
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return 0;
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}
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case BLKRAGET:
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case BLKFRAGET:
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if (!arg)
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return -EINVAL;
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bdi = blk_get_backing_dev_info(bdev);
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return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
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case BLKROGET:
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return put_int(arg, bdev_read_only(bdev) != 0);
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case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
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return put_int(arg, block_size(bdev));
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case BLKSSZGET: /* get block device logical block size */
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return put_int(arg, bdev_logical_block_size(bdev));
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case BLKPBSZGET: /* get block device physical block size */
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return put_uint(arg, bdev_physical_block_size(bdev));
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case BLKIOMIN:
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return put_uint(arg, bdev_io_min(bdev));
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case BLKIOOPT:
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return put_uint(arg, bdev_io_opt(bdev));
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case BLKALIGNOFF:
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return put_int(arg, bdev_alignment_offset(bdev));
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case BLKDISCARDZEROES:
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return put_uint(arg, bdev_discard_zeroes_data(bdev));
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case BLKSECTGET:
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max_sectors = min_t(unsigned int, USHRT_MAX,
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queue_max_sectors(bdev_get_queue(bdev)));
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return put_ushort(arg, max_sectors);
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case BLKROTATIONAL:
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return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
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case BLKRASET:
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case BLKFRASET:
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if(!capable(CAP_SYS_ADMIN))
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return -EACCES;
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bdi = blk_get_backing_dev_info(bdev);
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bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
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return 0;
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case BLKBSZSET:
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/* set the logical block size */
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if (!capable(CAP_SYS_ADMIN))
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return -EACCES;
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if (!arg)
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return -EINVAL;
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if (get_user(n, (int __user *) arg))
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return -EFAULT;
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if (!(mode & FMODE_EXCL)) {
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bdgrab(bdev);
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if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
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return -EBUSY;
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}
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ret = set_blocksize(bdev, n);
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if (!(mode & FMODE_EXCL))
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blkdev_put(bdev, mode | FMODE_EXCL);
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return ret;
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case BLKPG:
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ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
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break;
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case BLKRRPART:
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ret = blkdev_reread_part(bdev);
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break;
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case BLKGETSIZE:
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size = i_size_read(bdev->bd_inode);
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if ((size >> 9) > ~0UL)
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return -EFBIG;
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return put_ulong(arg, size >> 9);
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case BLKGETSIZE64:
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return put_u64(arg, i_size_read(bdev->bd_inode));
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case BLKTRACESTART:
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case BLKTRACESTOP:
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case BLKTRACESETUP:
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case BLKTRACETEARDOWN:
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ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
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break;
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default:
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ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(blkdev_ioctl);
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