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Commit 351499a1 authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Jens Axboe
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block: Invalidate cache on discard v2 



It is reasonable drop page cache on discard, otherwise that pages may
be written by writeback second later, so thin provision devices will
not be happy. This seems to be a  security leak in case of secure discard case.

Also add check for queue_discard flag on early stage.

Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 75bc5f06

block/ioctl.c

+10 −4
Original line number Diff line number Diff line
@@ -202,10 +202,16 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode, 
{

	uint64_t range[2];

	uint64_t start, len;

	struct request_queue *q = bdev_get_queue(bdev);

	struct address_space *mapping = bdev->bd_inode->i_mapping;





	if (!(mode & FMODE_WRITE))

		return -EBADF;



	if (!blk_queue_discard(q))

		return -EOPNOTSUPP;



	if (copy_from_user(range, (void __user *)arg, sizeof(range)))

		return -EFAULT;
@@ -216,12 +222,12 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode, 
		return -EINVAL;

	if (len & 511)

		return -EINVAL;

	start >>= 9;

	len >>= 9;



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

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

		return -EINVAL;

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

	truncate_inode_pages_range(mapping, start, start + len);

	return blkdev_issue_discard(bdev, start >> 9, len >> 9,

				    GFP_KERNEL, flags);

}



static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,