[PATCH 1/2] btrfs: add error message for metadata level mismatch

[Qu Wenruo <wqu@suse.com>]

From a recent regression report, we found that after commit 947a629988f1
("btrfs: move tree block parentness check into
validate_extent_buffer()") if we have a level mismatch (false alert
though), there is no error message at all.

This makes later debug much harder.

This patch will add the proper error message for such case.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f8b5955f003f..ec48adba2ae9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -530,6 +530,10 @@ static int validate_extent_buffer(struct extent_buffer *eb,
 	}
 
 	if (found_level != check->level) {
+		btrfs_err(fs_info,
+	"level verify failed on logical %llu mirror %u wanted %u found %u",
+			  eb->start, eb->read_mirror, check->level,
+			  found_level);
 		ret = -EIO;
 		goto out;
 	}
-- 
2.39.0