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Groups > linux.kernel > #1396115 > unrolled thread

[PATCH BUGFIX] block: add missing group association in bio_split

Started byPaolo Valente <paolo.valente@linaro.org>
First post2016-05-06 23:30 +0200
Last post2016-05-09 17:30 +0200
Articles 4 on this page of 24 — 7 participants

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  [PATCH BUGFIX] block: add missing group association in bio_split Paolo Valente <paolo.valente@linaro.org> - 2016-05-06 23:30 +0200
    Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-09 16:20 +0200
      Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-09 16:40 +0200
        Re: [PATCH BUGFIX] block: add missing group association in bio_split Paolo <paolo.valente@linaro.org> - 2016-05-09 16:40 +0200
          Re: [PATCH BUGFIX] block: add missing group association in bio_split Mark Brown <broonie@kernel.org> - 2016-05-09 17:00 +0200
            Re: [PATCH BUGFIX] block: add missing group association in bio_split Jens Axboe <axboe@kernel.dk> - 2016-05-09 20:00 +0200
              [PATCH BUGFIX] block: add missing group association in bio_split Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 11:10 +0200
                Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-10 18:20 +0200
                  Re: [PATCH BUGFIX] block: add missing group association in bio_split Paolo <paolo.valente@linaro.org> - 2016-05-10 19:10 +0200
                  [PATCH BUGFIX] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 22:30 +0200
                    Re: [PATCH BUGFIX] block: add missing group association in  bio-cloning functions Tejun Heo <tj@kernel.org> - 2016-05-10 22:50 +0200
                      Re: [PATCH BUGFIX V2] block: add missing group association in  bio-cloning functions Tejun Heo <tj@kernel.org> - 2016-05-10 23:10 +0200
                      [PATCH BUGFIX V2] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 23:10 +0200
                        Re: [PATCH BUGFIX V2] block: add missing group association in bio-cloning functions Jeff Moyer <jmoyer@redhat.com> - 2016-05-10 23:40 +0200
                          Re: [PATCH BUGFIX V2] block: add missing group association in  bio-cloning functions Paolo <paolo.valente@linaro.org> - 2016-05-10 23:50 +0200
                          [PATCH BUGFIX V3] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-11 00:10 +0200
                            Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Nikolay Borisov <kernel@kyup.com> - 2016-05-11 08:40 +0200
                              Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Nikolay Borisov <kernel@kyup.com> - 2016-05-11 08:50 +0200
                                Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Paolo <paolo.valente@linaro.org> - 2016-05-11 11:10 +0200
                                [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-11 11:30 +0200
                                  Re: [PATCH BUGFIX V4] block: add missing group association in  bio-cloning functions Tejun Heo <tj@kernel.org> - 2016-05-12 17:30 +0200
                                  Re: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions Jeff Moyer <jmoyer@redhat.com> - 2016-05-13 22:50 +0200
          Re: [PATCH BUGFIX] block: add missing group association in bio_split Jens Axboe <axboe@kernel.dk> - 2016-05-09 17:00 +0200
    Re: [PATCH BUGFIX] block: add missing group association in bio_split Tejun Heo <tj@kernel.org> - 2016-05-09 17:30 +0200

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#1400148 — Re: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions

FromTejun Heo <tj@kernel.org>
Date2016-05-12 17:30 +0200
SubjectRe: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions
Message-ID<ry0IN-eN-3@gated-at.bofh.it>
In reply to#1398841
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@linaro.org>
> Reviewed-by: Nikolay Borisov <kernel@kyup.com>

 Acked-by: Tejun Heo <tj@kernel.org>

It prolly should also have the following tags

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

Thanks.

-- 
tejun

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#1400968 — Re: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions

FromJeff Moyer <jmoyer@redhat.com>
Date2016-05-13 22:50 +0200
SubjectRe: [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions
Message-ID<rysc3-2oB-15@gated-at.bofh.it>
In reply to#1398841
Paolo Valente <paolo.valente@linaro.org> writes:

> 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@linaro.org>
> Reviewed-by: Nikolay Borisov <kernel@kyup.com>

I think this one's golden!  Thanks, Paolo!

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>


> ---
> Tejun: I didn't add also your Ack, just because this version is slightly
> different from the one you acked.
> ---
>  block/bio.c          | 15 +++++++++++++++
>  fs/btrfs/extent_io.c |  6 ------
>  include/linux/bio.h  |  3 +++
>  3 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index 807d25e..89f517c 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -590,6 +590,8 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
>  	bio->bi_rw = bio_src->bi_rw;
>  	bio->bi_iter = bio_src->bi_iter;
>  	bio->bi_io_vec = bio_src->bi_io_vec;
> +
> +	bio_clone_blkcg_association(bio, bio_src);
>  }
>  EXPORT_SYMBOL(__bio_clone_fast);
>  
> @@ -695,6 +697,8 @@ integrity_clone:
>  		}
>  	}
>  
> +	bio_clone_blkcg_association(bio, bio_src);
> +
>  	return bio;
>  }
>  EXPORT_SYMBOL(bio_clone_bioset);
> @@ -2016,6 +2020,17 @@ void bio_disassociate_task(struct bio *bio)
>  	}
>  }
>  
> +/**
> + * bio_clone_blkcg_association - clone blkcg association from src to dst bio
> + * @dst: destination bio
> + * @src: source bio
> + */
> +void bio_clone_blkcg_association(struct bio *dst, struct bio *src)
> +{
> +	if (src->bi_css)
> +		WARN_ON(bio_associate_blkcg(dst, src->bi_css));
> +}
> +
>  #endif /* CONFIG_BLK_CGROUP */
>  
>  static void __init biovec_init_slabs(void)
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index d247fc0..19f6739 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -2686,12 +2686,6 @@ struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
>  		btrfs_bio->csum = NULL;
>  		btrfs_bio->csum_allocated = NULL;
>  		btrfs_bio->end_io = NULL;
> -
> -#ifdef CONFIG_BLK_CGROUP
> -		/* FIXME, put this into bio_clone_bioset */
> -		if (bio->bi_css)
> -			bio_associate_blkcg(new, bio->bi_css);
> -#endif
>  	}
>  	return new;
>  }
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index 6b7481f..16cbe59 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -527,11 +527,14 @@ extern unsigned int bvec_nr_vecs(unsigned short idx);
>  int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
>  int bio_associate_current(struct bio *bio);
>  void bio_disassociate_task(struct bio *bio);
> +void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
>  #else	/* CONFIG_BLK_CGROUP */
>  static inline int bio_associate_blkcg(struct bio *bio,
>  			struct cgroup_subsys_state *blkcg_css) { return 0; }
>  static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
>  static inline void bio_disassociate_task(struct bio *bio) { }
> +static inline void bio_clone_blkcg_association(struct bio *dst,
> +			struct bio *src) { return 0; }
>  #endif	/* CONFIG_BLK_CGROUP */
>  
>  #ifdef CONFIG_HIGHMEM

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#1397120

FromJens Axboe <axboe@kernel.dk>
Date2016-05-09 17:00 +0200
Message-ID<rwUP9-7Fi-17@gated-at.bofh.it>
In reply to#1397101
On 05/09/2016 08:39 AM, Paolo wrote:
> Il 09/05/2016 16:35, Jeff Moyer ha scritto:
>> Jeff Moyer <jmoyer@redhat.com> writes:
>>
>>> Paolo Valente <paolo.valente@linaro.org> writes:
>>>
>>>> @@ -1811,6 +1811,11 @@ struct bio *bio_split(struct bio *bio, int
>>>> sectors,
>>>>
>>>>       bio_advance(bio, split->bi_iter.bi_size);
>>>>
>>>> +#ifdef CONFIG_BLK_CGROUP
>>>> +    if (bio->bi_css)
>>>> +        bio_associate_blkcg(split, bio->bi_css);
>>>> +#endif
>>>> +
>>>>       return split;
>>>>   }
>>>>   EXPORT_SYMBOL(bio_split);
>>>
>>> Get rid of the #ifdefery.  This should be just:
>>>
>>> bio_associate_blkcg(split, bio->bi_css);
>>
>> Gah, I see that the bi_css member is only present for CONFIG_BLK_CGROUP.
>> I guess we'll have to live with the ifdef.
>>
>
> We have already tried to remove it, but it seems it would require other
> major changes.

It'd be cleaner to have a

bio_clone_associate_blkcg(split, bio);

or similar, and then hide it in there.

-- 
Jens Axboe

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#1397141

FromTejun Heo <tj@kernel.org>
Date2016-05-09 17:30 +0200
Message-ID<rwVi9-8if-1@gated-at.bofh.it>
In reply to#1396115
On Fri, May 06, 2016 at 10:45:12PM +0200, Paolo Valente wrote:
> When a bio is split, 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 frequency of splits, 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 then broken.
> 
> This commit adds the missing association in bio_split.
> 
> Signed-off-by: Paolo Valente <paolo.valente@linaro.org>

Acked-by: Tejun Heo <tj@kernel.org>

> ---
>  block/bio.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/block/bio.c b/block/bio.c
> index 807d25e..c4a3834 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -1811,6 +1811,11 @@ struct bio *bio_split(struct bio *bio, int sectors,
>  
>  	bio_advance(bio, split->bi_iter.bi_size);
>  
> +#ifdef CONFIG_BLK_CGROUP
> +	if (bio->bi_css)
> +		bio_associate_blkcg(split, bio->bi_css);
> +#endif

And yeah, we need to encapsulate this better to avoid scattering
CONFIG_BLK_CGROUP but that's for another patch.

Thanks.

-- 
tejun

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