btrfs: use level argument in log tree walk callback replay_one_buffer()

We already have the extent buffer's level in an argument, there's no need
to first ensure the extent buffer's data is loaded (by calling
btrfs_read_extent_buffer()) and then call btrfs_header_level() to check
the level. So use the level argument and do the check before calling
btrfs_read_extent_buffer().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/tree-log.c

@@ -2591,17 +2591,15 @@ static int replay_one_buffer(struct extent_buffer *eb,
 	int i;
 	int ret;
 
+	if (level != 0)
+		return 0;
+
 	ret = btrfs_read_extent_buffer(eb, &check);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		return ret;
 	}
 
-	level = btrfs_header_level(eb);
-
-	if (level != 0)
-		return 0;
-
 	path = btrfs_alloc_path();
 	if (!path) {
 		btrfs_abort_transaction(trans, -ENOMEM);