f2fs: fix to avoid potential race on sbi->unusable_block_count access/update

Use sbi.stat_lock to protect sbi->unusable_block_count accesss/udpate, in
order to avoid potential race on it.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 805a33088e82..ed70b68b2b38 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1536,7 +1536,11 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
         clear_sbi_flag(sbi, SBI_IS_DIRTY);
         clear_sbi_flag(sbi, SBI_NEED_CP);
         clear_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);
+
+        spin_lock(&sbi->stat_lock);
         sbi->unusable_block_count = 0;
+        spin_unlock(&sbi->stat_lock);
+
         __set_cp_next_pack(sbi);
 
         /*