From: Chao Yu <yuchao0@huawei.com>
To: Jaegeuk Kim <jaegeuk@kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-f2fs-devel@lists.sourceforge.net>,
<kernel-team@android.com>
Cc: Light Hsieh <Light.Hsieh@mediatek.com>
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: avoid race condition for shinker count
Date: Thu, 12 Nov 2020 14:57:22 +0800 [thread overview]
Message-ID: <4aae85c2-1829-06c0-8fd1-4148100dc0b9@huawei.com> (raw)
In-Reply-To: <20201112054051.GA4092972@google.com>
On 2020/11/12 13:40, Jaegeuk Kim wrote:
> Light reported sometimes shinker gets nat_cnt < dirty_nat_cnt resulting in
> wrong do_shinker work. Let's avoid to get stale data by using nat_tree_lock.
>
> Reported-by: Light Hsieh <Light.Hsieh@mediatek.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
> v3:
> - fix to use NM_I(sbi)
>
> fs/f2fs/shrinker.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
> index d66de5999a26..555712ba06d8 100644
> --- a/fs/f2fs/shrinker.c
> +++ b/fs/f2fs/shrinker.c
> @@ -18,7 +18,11 @@ static unsigned int shrinker_run_no;
>
> static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
> {
> - long count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
> + long count;
> +
> + down_read(&NM_I(sbi)->nat_tree_lock);
> + count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
> + up_read(&NM_I(sbi)->nat_tree_lock);
>
> return count > 0 ? count : 0;
Minor thing,
Just return count is enough? since count should never be smaller than 0.
Anyway,
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Thanks,
Thanks,
> }
>
next prev parent reply other threads:[~2020-11-12 6:57 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 17:00 [PATCH] f2fs: avoid race condition for shinker count Jaegeuk Kim
2020-11-10 2:15 ` [f2fs-dev] " Chao Yu
2020-11-10 4:19 ` Jaegeuk Kim
2020-11-10 6:04 ` Chao Yu
2020-11-12 5:31 ` Jaegeuk Kim
2020-11-12 5:34 ` [PATCH v2] " Jaegeuk Kim
2020-11-12 5:40 ` [f2fs-dev] [PATCH v3] " Jaegeuk Kim
2020-11-12 6:57 ` Chao Yu [this message]
2020-11-17 16:40 ` Jaegeuk Kim
2020-12-03 6:07 ` Jaegeuk Kim
2020-12-03 6:55 ` Chao Yu
2020-12-03 7:55 ` Jaegeuk Kim
2020-12-03 8:16 ` Chao Yu
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