Messages in this thread Patch in this message | | | Date | Wed, 11 Nov 2020 21:34:14 -0800 | From | Jaegeuk Kim <> | Subject | Re: [PATCH v2] f2fs: avoid race condition for shinker count |
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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> --- 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..d42245ab07f4 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->nat_tree_lock); + count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt; + up_read(&nm_i->nat_tree_lock); return count > 0 ? count : 0; } -- 2.29.2.299.gdc1121823c-goog
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