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, 1 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8388d2abacb5..8dee063c833f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2169,8 +2169,11 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
                          * before, we must track that to know how much space we
                          * really have.
                          */
-                        if (f2fs_test_bit(offset, se->ckpt_valid_map))
+                        if (f2fs_test_bit(offset, se->ckpt_valid_map)) {
+                                spin_lock(&sbi->stat_lock);
                                 sbi->unusable_block_count++;
+                                spin_unlock(&sbi->stat_lock);
+                        }
                 }
 
                 if (f2fs_test_and_clear_bit(offset, se->discard_map))