[PATCH v2] f2fs: skip further SIT updates for already invalidated blocks

[Seongjae Jeong]

When update_sit_entry_for_release() encounters a block whose bit is
already cleared in cur_valid_map, it reports the inconsistency and
corrects se->valid_blocks and del. However, it still proceeds with
the discard bitmap and checkpoint accounting updates.

This can clear the discard bit unnecessarily and incorrectly decrement
the segment and section ckpt_valid_blocks counters when the block is
not marked in ckpt_valid_map.

Continue to the next block after correcting se->valid_blocks and del,
so that an already invalidated block does not trigger further discard
bitmap or checkpoint counter updates.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 81ffbd224e5f ("f2fs: update_sit_entry_for_release() supports consecutive blocks.")
Fixes: a66cdd985532 ("f2fs: introduce discard_map for f2fs_trim_fs")
Signed-off-by: Seongjae Jeong <jsjlee1020@xxxxxxxxx>
---
V1 -> V2:
- Add Cc: stable@xxxxxxxxxxxxxxx.
- Add a Fixes tag for the discard bitmap handling.

Fixes tags:
- 81ffbd224e5f introduced the segment checkpoint accounting regression
  by replacing the del-based adjustment with a fixed decrement.
- a66cdd985532 introduced the discard bitmap update that still runs
  when the block is already invalid.

 fs/f2fs/segment.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 51858f64e43e..fc2f0fd8e318 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2560,7 +2560,10 @@ static int update_sit_entry_for_release(struct f2fs_sb_info *sbi, struct seg_ent
 			f2fs_bug_on(sbi, 1);
 			se->valid_blocks++;
 			del += 1;
-		} else if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
+			continue;
+		}
+
+		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
 			/*
 			 * If checkpoints are off, we must not reuse data that
 			 * was used in the previous checkpoint. If it was used
-- 
2.53.0