- InnoDB tries to write FILE_CHECKPOINT marker during
early recovery when log file size is insufficient.
While updating the log checkpoint at the end of the recovery,
InnoDB must already have written out all pending changes
to the persistent files. To complete the checkpoint, InnoDB
has to write some log records for the checkpoint and to
update the checkpoint header. If the server gets killed
before updating the checkpoint header then it would lead
the logfile to be unrecoverable.

- This patch avoids FILE_CHECKPOINT marker during early
recovery and narrows down the window of opportunity to
make the log file unrecoverable.