Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v3] f2fs: avoid race condition for shinker count | From | Chao Yu <> | Date | Thu, 12 Nov 2020 14:57:22 +0800 |
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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,
> } >
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