[PATCH] f2fs: report cp block corrupted

[Weichao Guo <guoweichao@huawei.com>]

There is a potential inconsistent metadata case due to a cp block
crc invalid in the latest checkpoint caused by hardware issues:
1) write nodes into segment x;
2) write checkpoint A;
3) remove nodes in segment x;
4) write checkpoint B;
5) issue discard or write datas into segment x;
6) sudden power-cut;
7) use checkpoint A after reboot as checkpoint B is invalid

This inconsistency may be found after several reboots long time later
and the kernel log about cp block crc invalid has disappeared. This
makes the root cause of the inconsistency is hard to locate. Let us
separate such other part issues from f2fs logical bugs in debug version.

Signed-off-by: Weichao Guo <guoweichao@huawei.com>
---
 fs/f2fs/checkpoint.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 512dca8..15baba75 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -730,6 +730,7 @@ static int get_checkpoint_version(struct f2fs_sb_info *sbi, block_t cp_addr,
 	unsigned long blk_size = sbi->blocksize;
 	size_t crc_offset = 0;
 	__u32 crc = 0;
+	int err = 0;

 	*cp_page = get_meta_page(sbi, cp_addr);
 	*cp_block = (struct f2fs_checkpoint *)page_address(*cp_page);
@@ -737,18 +738,22 @@ static int get_checkpoint_version(struct f2fs_sb_info *sbi, block_t cp_addr,
 	crc_offset = le32_to_cpu((*cp_block)->checksum_offset);
 	if (crc_offset > (blk_size - sizeof(__le32))) {
 		f2fs_msg(sbi->sb, KERN_WARNING,
-			"invalid crc_offset: %zu", crc_offset);
-		return -EINVAL;
+			"invalid crc_offset: %zu at blk_addr: 0x%x",
+				crc_offset, cp_addr);
+		err = -EINVAL;
+		f2fs_bug_on(sbi, 1);
 	}

 	crc = cur_cp_crc(*cp_block);
 	if (!f2fs_crc_valid(sbi, crc, *cp_block, crc_offset)) {
-		f2fs_msg(sbi->sb, KERN_WARNING, "invalid crc value");
-		return -EINVAL;
+		f2fs_msg(sbi->sb, KERN_WARNING,
+			"invalid crc value at blk_addr: 0x%x", cp_addr);
+		err = -EINVAL;
+		f2fs_bug_on(sbi, 1);
 	}

 	*version = cur_cp_version(*cp_block);
-	return 0;
+	return err;
 }

 static struct page *validate_checkpoint(struct f2fs_sb_info *sbi,
--
2.10.1


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