Re: [PATCH] btrfs: qgroups: Fix BUG_ON condition

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

在 2017年07月12日 14:42, Nikolay Borisov 写道:
> The current code was erroneously checking for root_level > BTRFS_MAX_LEVEL. If
> we had a root_level of 8 then the check won't trigger and we could
> potentially hit a buffer overflow. The correct check should be
> root_level >= BTRFS_MAX_LEVEL

Thanks for catching this.

Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com>

> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>   fs/btrfs/qgroup.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 4ce351efe281..3b787915ef31 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1603,7 +1603,7 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
>   	struct extent_buffer *eb = root_eb;
>   	struct btrfs_path *path = NULL;
>   
> -	BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
> +	BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
>   	BUG_ON(root_eb == NULL);
>   
>   	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
> @@ -2959,7 +2959,7 @@ static int __btrfs_qgroup_release_data(struct inode *inode,
>   	if (free && reserved)
>   		return qgroup_free_reserved_data(inode, reserved, start, len);
>   	extent_changeset_init(&changeset);
> -	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
> +	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
>   			start + len -1, EXTENT_QGROUP_RESERVED, &changeset);

I didn't recongize it's a tailing white space at first.
Nice catch.

Thanks,
Qu

>   	if (ret < 0)
>   		goto out;
>