Disk drive with efficient handling of off-track events during sequential write

A disk drive comprising:

• a magnetic disk with a recording surface;
• a head configured to access the recording surface;
• and
• a controller configured to:
• move the head to a first track to start a disk access operation;
• control the head to perform the disk access operation on one or more sectors of the first track beginning at a first sector of the first track;
• if there are any sectors in a second track to be written as part of the disk access operation after the head has performed the disk access operation on all sectors of the first track to be written as part of the disk access operation, determine whether or not an off-track event occurred while the head was performing the disk access operation on any of the sectors of the first track;
• and
• upon determining that the off-track event occurred while the head was performing the disk access operation on any of the sectors of the first track to be written as part of the disk access operation, moving the head to the second track and control the head to write sequentially to one or more sectors of the second track beginning at a first sector of the second track.