Re: [PATCH 1/2] btrfs: forbid creating subvol qgroups

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2024/1/20 11:25, Boris Burkov wrote:
> This leads to various races and it isn't helpful, because you can't
> specify a subvol id when creating a subvol, so you can't be sure it
> will be the right one. Any requirements on the automatic subvol can
> be gratified by using a higher level qgroup and the inheritance
> parameters of subvol creation.
>
> Signed-off-by: Boris Burkov <boris@bur.io>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/ioctl.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 58e0c59bc4cd..3d476decde52 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3815,6 +3815,11 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
>   		goto out;
>   	}
>
> +	if (sa->create && is_fstree(sa->qgroupid)) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>   	trans = btrfs_join_transaction(root);
>   	if (IS_ERR(trans)) {
>   		ret = PTR_ERR(trans);