Re: [PATCH v7 15/43] btrfs: implement fscrypt ioctls

On Wed, May 13, 2026 at 10:52:49AM +0200, Daniel Vacek wrote:
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 6a37dd3cc5ee..2e0b79f41197 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -5159,6 +5159,35 @@ long btrfs_ioctl(struct file *file, unsigned int
>  		return btrfs_ioctl_get_fslabel(fs_info, argp);
>  	case FS_IOC_SETFSLABEL:
>  		return btrfs_ioctl_set_fslabel(file, argp);
> +#ifdef CONFIG_BTRFS_EXPERIMENTAL
> +	case FS_IOC_SET_ENCRYPTION_POLICY: {
> +		if (!IS_ENABLED(CONFIG_FS_ENCRYPTION))
> +			return -EOPNOTSUPP;
> +		if (sb_rdonly(fs_info->sb))
> +			return -EROFS;
> +		/*
> +		 *  If we crash before we commit, nothing encrypted could have
> +		 * been written so it doesn't matter whether the encrypted
> +		 * state persists.
> +		 */
> +		btrfs_set_fs_incompat(fs_info, ENCRYPT);
> +		return fscrypt_ioctl_set_policy(file, (const void __user *)arg);
> +	}
> +	case FS_IOC_GET_ENCRYPTION_POLICY:
> +		return fscrypt_ioctl_get_policy(file, (void __user *)arg);
> +	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
> +		return fscrypt_ioctl_get_policy_ex(file, (void __user *)arg);
> +	case FS_IOC_ADD_ENCRYPTION_KEY:
> +		return fscrypt_ioctl_add_key(file, (void __user *)arg);
> +	case FS_IOC_REMOVE_ENCRYPTION_KEY:
> +		return fscrypt_ioctl_remove_key(file, (void __user *)arg);
> +	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
> +		return fscrypt_ioctl_remove_key_all_users(file, (void __user *)arg);
> +	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
> +		return fscrypt_ioctl_get_key_status(file, (void __user *)arg);
> +	case FS_IOC_GET_ENCRYPTION_NONCE:
> +		return fscrypt_ioctl_get_nonce(file, (void __user *)arg);
> +#endif /* CONFIG_BTRFS_EXPERIMENTAL */

Are you sure you want to auto-enable the "encrypt" feature flag like
this?  It doesn't even require a privilege.

It's also only in FS_IOC_SET_ENCRYPTION_POLICY, so this doesn't work in
cases where users add a key first.

- Eric