[PATCH 1/2] btrfs-progs: check: Detect overlap csum items

[Qu Wenruo <wqu@suse.com>]

There is a report about csum item overlap, which makes newer btrfs
kernel to reject it due to tree-checker.

Now let btrfs-progs have the same ability to detect such problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 check/main.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/check/main.c b/check/main.c
index d02dd1636852..c526c72d158e 100644
--- a/check/main.c
+++ b/check/main.c
@@ -5893,6 +5893,7 @@ static int check_csums(struct btrfs_root *root)
 	struct btrfs_path path;
 	struct extent_buffer *leaf;
 	struct btrfs_key key;
+	u64 last_data_end = 0;
 	u64 offset = 0, num_bytes = 0;
 	u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
 	int errors = 0;
@@ -5952,6 +5953,13 @@ static int check_csums(struct btrfs_root *root)
 			continue;
 		}
 
+		if (key.offset < last_data_end) {
+			error(
+	"csum overlap, current bytenr=%llu prev_end=%llu, eb=%llu slot=%u",
+				key.offset, last_data_end, leaf->start,
+				path.slots[0]);
+			errors++;
+		}
 		data_len = (btrfs_item_size_nr(leaf, path.slots[0]) /
 			      csum_size) * root->fs_info->sectorsize;
 		if (!verify_csum)
@@ -5982,6 +5990,7 @@ skip_csum_check:
 			num_bytes = 0;
 		}
 		num_bytes += data_len;
+		last_data_end = key.offset + data_len;
 		path.slots[0]++;
 	}
 
-- 
2.25.1