btrfs_sb_log_location
ret = btrfs_sb_log_location(device, i, WRITE, &bytenr);
ret = btrfs_sb_log_location(device, i, READ, &bytenr);
ret = btrfs_sb_log_location(scrub_dev, i, 0, &bytenr);
int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,