Re: [PATCH vfs.all 04/26] block: prevent direct access of bd_inode

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi,

在 2024/04/07 10:22, Al Viro 写道:
> On Sat, Apr 06, 2024 at 05:09:08PM +0800, Yu Kuai wrote:
> > @@ -669,7 +669,7 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >   {
> >   	struct file *file = iocb->ki_filp;
> >   	struct block_device *bdev = I_BDEV(file->f_mapping->host);
> > -	struct inode *bd_inode = bdev->bd_inode;
> > +	struct inode *bd_inode = bdev_inode(bdev);
>
> What you want here is this:
>
> 	struct inode *bd_inode = file->f_mapping->host;
> 	struct block_device *bdev = I_BDEV(bd_inode);

Yes, this way is better, logically.
> > --- a/block/ioctl.c
> > +++ b/block/ioctl.c
> > @@ -97,7 +97,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
> >   {
> >   	uint64_t range[2];
> >   	uint64_t start, len;
> > -	struct inode *inode = bdev->bd_inode;
> > +	struct inode *inode = bdev_inode(bdev);
> >   	int err;
>
> The uses of 'inode' in this function are
>          filemap_invalidate_lock(inode->i_mapping);
> and
>          filemap_invalidate_unlock(inode->i_mapping);
>
> IOW, you want bdev_mapping(bdev), not bdev_inode(bdev).
>
> > @@ -166,7 +166,7 @@ static int blk_ioctl_zeroout(struct block_device *bdev, blk_mode_t mode,
> >   {
> >   	uint64_t range[2];
> >   	uint64_t start, end, len;
> > -	struct inode *inode = bdev->bd_inode;
> > +	struct inode *inode = bdev_inode(bdev);
>
> Same story.

Yes.

Thanks for the suggestions!
Kuai

> .