The original fix was accidentally pushed to mysql-5.1 after the 5.1.59
clone-off in bzr revision id
marko.makela@oracle.com-20110829081642-z0w992a0mrc62s6w with thne fix
of Bug#12704861 Corruption after a crash during BLOB update.
It was pushed separately to mysql-5.5 in bzr revision id
marko.makela@oracle.com-20110901184804-2901f6qmuro3jas8.

trx_undo_report_row_operation(): If the page for which the undo log
was too big was empty, commit and start the mini-transaction before
acquiring the rollback segment mutex and freeing the undo page. This
is necessary, because the mini-transaction may be holding lower-order
latches in the levels SYNC_FSP and SYNC_FSP_PAGE.

trx_undo_erase_page_end(): Erase also empty pages, because
trx_undo_report_row_operation() needs to commit the mini-transaction
before freeing the empty page.

rb:756 approved by Sunny Bains