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SubjectRe: [PATCH v2] f2fs: avoid race condition for shinker count
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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