[PATCH 1/3] btrfs check: Fix wrong level access

[Hugo Mills <hugo@carfax.org.uk>]

There's no reason to assume that the bad key order is in a leaf block,
so accessing level 0 of the path is going to be an error if it's actually
a node block that's bad.

Reported-by: Chris Mason <clm@fb.com>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
---
 cmds-check.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/cmds-check.c b/cmds-check.c
index d195e7a..fc84ad8 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -2418,6 +2418,7 @@ static int try_to_fix_bad_block(struct btrfs_trans_handle *trans,
 	struct btrfs_path *path;
 	struct btrfs_key k1, k2;
 	int i;
+	int level;
 	int ret;
 
 	if (status != BTRFS_TREE_BLOCK_BAD_KEY_ORDER)
@@ -2435,9 +2436,10 @@ static int try_to_fix_bad_block(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -EIO;
 
-	path->lowest_level = btrfs_header_level(buf);
+	level = btrfs_header_level(buf);
+	path->lowest_level = level;
 	path->skip_check_block = 1;
-	if (btrfs_header_level(buf))
+	if (level)
 		btrfs_node_key_to_cpu(buf, &k1, 0);
 	else
 		btrfs_item_key_to_cpu(buf, &k1, 0);
@@ -2448,9 +2450,9 @@ static int try_to_fix_bad_block(struct btrfs_trans_handle *trans,
 		return -EIO;
 	}
 
-	buf = path->nodes[0];
+	buf = path->nodes[level];
 	for (i = 0; i < btrfs_header_nritems(buf) - 1; i++) {
-		if (btrfs_header_level(buf)) {
+		if (level) {
 			btrfs_node_key_to_cpu(buf, &k1, i);
 			btrfs_node_key_to_cpu(buf, &k2, i + 1);
 		} else {
-- 
1.9.2