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: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/ioctl.c b/block/ioctl.c
index 0de02ee..c0fc32b 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -202,10 +202,16 @@
{
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 @@
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,