btrfs: fix a potential path leak in print_data_reloc_error()

Inside print_data_reloc_error(), if extent_from_logical() failed we
return immediately.

However there are the following cases where extent_from_logical() can
return error but still holds a path:

- btrfs_search_slot() returned 0

- No backref item found in extent tree

- No flags_ret provided
  This is not possible in this call site though.

So for the above two cases, we can return without releasing the path,
causing extent buffer leaks.

Fixes: b9a9a85059 ("btrfs: output affected files when relocation fails")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -255,6 +255,7 @@ static void print_data_reloc_error(const struct btrfs_inode *inode, u64 file_off
 	if (ret < 0) {
 		btrfs_err_rl(fs_info, "failed to lookup extent item for logical %llu: %d",
 			     logical, ret);
+		btrfs_release_path(&path);
 		return;
 	}
 	eb = path.nodes[0];