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block: Invalidate cache on discard v2

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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: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Dmitry Monakhov 2017-10-24 18:44:57 -06:00 committed by Jens Axboe
parent 75bc5f0661
commit 351499a172
1 changed files with 10 additions and 4 deletions
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14
block/ioctl.c
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@ -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,