Re: [PATCH v2] Btrfs: add label to snapshot and subvol

[Anand Jain <Anand.Jain@oracle.com>]

Hi Maio,

  Thanks for the review.
  Was away for sometime sorry for delay, have sent out the
  patch with review comments accepted.

-Anand

On 11/16/2012 02:33 PM, Miao Xie wrote:
> Hi, Anand
>
> On fri, 16 Nov 2012 12:52:25 +0800, Anand jain wrote:
>> +static int btrfs_ioctl_subvol_getlabel(struct btrfs_root *root,
>> +						void __user *arg)
>> +{
>> +	char *label;
>> +
>> +	label = btrfs_root_label(&root->root_item);
>> +	if (copy_to_user(arg, label, BTRFS_SUBVOL_LABEL_SIZE))
>> +		return -EFAULT;
>> +	return 0;
>> +}
>> +
>> +static int btrfs_ioctl_subvol_setlabel(struct btrfs_root *root,
>> +						void __user *arg)
>> +{
>> +	char label[BTRFS_SUBVOL_LABEL_SIZE+1];
>> +	struct btrfs_trans_handle *trans;
>> +
>> +	if (copy_from_user(label, arg, BTRFS_SUBVOL_LABEL_SIZE))
>> +		return -EFAULT;
>> +	trans = btrfs_join_transaction(root);
>> +	if (IS_ERR(trans))
>> +		return PTR_ERR(trans);
>> +	btrfs_root_set_label(&root->root_item, label);
>> +	btrfs_end_transaction(trans, root);
>
> We need a lock to protect the label, and besides that, we need to get the write
> access before we set the label for the subvolume.
>
> Thanks
> Miao
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>