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References: <20240201092559.910982-1-yukuai1@huaweicloud.com> <20240201092559.910982-7-yukuai1@huaweicloud.com>
In-Reply-To: <20240201092559.910982-7-yukuai1@huaweicloud.com>
From: Song Liu <song@kernel.org>
Date: Wed, 7 Feb 2024 23:47:52 -0800
Message-ID: <CAPhsuW51gFwRdCNmoLuwmCuofAKetV2-gj-5Hb3fNGgu+5yUyA@mail.gmail.com>
Subject: Re: [PATCH v5 06/14] md: fix missing release of 'active_io' for flush
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: mpatocka@redhat.com, heinzm@redhat.com, xni@redhat.com, 
	blazej.kucman@linux.intel.com, agk@redhat.com, snitzer@kernel.org, 
	dm-devel@lists.linux.dev, yukuai3@huawei.com, jbrassow@f14.redhat.com, 
	neilb@suse.de, shli@fb.com, akpm@osdl.org, linux-kernel@vger.kernel.org, 
	linux-raid@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com
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On Thu, Feb 1, 2024 at 1:30=E2=80=AFAM Yu Kuai <yukuai1@huaweicloud.com> wr=
ote:
>
> From: Yu Kuai <yukuai3@huawei.com>
>
> submit_flushes
>  atomic_set(&mddev->flush_pending, 1);
>  rdev_for_each_rcu(rdev, mddev)
>   atomic_inc(&mddev->flush_pending);
>   bi->bi_end_io =3D md_end_flush
>   submit_bio(bi);
>                         /* flush io is done first */
>                         md_end_flush
>                          if (atomic_dec_and_test(&mddev->flush_pending))
>                           percpu_ref_put(&mddev->active_io)
>                           -> active_io is not released
>
>  if (atomic_dec_and_test(&mddev->flush_pending))
>   -> missing release of active_io
>
> For consequence, mddev_suspend() will wait for 'active_io' to be zero
> forever.
>
> Fix this problem by releasing 'active_io' in submit_flushes() if
> 'flush_pending' is decreased to zero.
>
> Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration=
")
> Reported-by: Blazej Kucman <blazej.kucman@linux.intel.com>
> Closes: https://lore.kernel.org/lkml/20240130172524.0000417b@linux.intel.=
com/
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Applied this patch to md-6.8.

Thanks,
Song