On 05/11/2016 09:38 AM, Nikolay Borisov wrote: > > > On 05/11/2016 01:01 AM, 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> >> --- >> block/bio.c | 15 +++++++++++++++ >> fs/btrfs/extent_io.c | 6 ------ >> include/linux/bio.h | 3 +++ >> 3 files changed, 18 insertions(+), 6 deletions(-) >> > > Just for reference something like that was already proposed (and tested) > before, though it never got merged : > > https://www.redhat.com/archives/dm-devel/2016-March/msg00007.html > > So you might also want to patch __bio_clone_fast to also apply this for > dm backed devices. Right, to correct myself: You might want to move the association to __blk_clone_fast that way you are also covering dm devices as well as users of bio_clone_fast. > > Otherwise: > > Reviewed-by: Nikolay Borisov <kernel@xxxxxxxx> > -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
