btrfs-progs: check: Fix wrong level access

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>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/cmds-check.c b/cmds-check.c
index da94079..df4af9a 100644 (file)
--- 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 {