Re: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions

[Tejun Heo]

On Wed, May 11, 2016 at 11:28:04AM +0200, Paolo Valente wrote:
> When a bio is cloned, the newly created bio must be associated with
> the same blkcg as the original bio (if BLK_CGROUP is enabled). If
> this operation is not performed, then the new bio is not associated
> with any group, and the group of the current task is returned when
> the group of the bio is requested.
> 
> Depending on the cloning frequency, this may cause a large
> percentage of the bios belonging to a given group to be treated
> as if belonging to other groups (in most cases as if belonging to
> the root group). The expected group isolation may thereby be broken.
> 
> This commit adds the missing association in bio-cloning functions.
> 
> Signed-off-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
> Reviewed-by: Nikolay Borisov <kernel@xxxxxxxx>

 Acked-by: Tejun Heo <tj@xxxxxxxxxx>

It prolly should also have the following tags

Fixes: da2f0f74cf7d ("Btrfs: add support for blkio controllers")
Cc: stable@xxxxxxxxxxxxxxx # v4.3+

Thanks.

-- 
tejun