MDEV-28457 Crash in page_dir_find_owner_slot()

A prominent remaining source of crashes on corrupted index pages
is page directory corruption.

A frequent caller of page_dir_find_owner_slot() is page_rec_get_prev().
Some of those calls can be replaced with simpler logic that is less
prone to fail.

page_dir_find_owner_slot(),
page_rec_get_prev(), page_rec_get_prev_const(),
btr_pcur_move_to_prev(), btr_pcur_move_to_prev_on_page(),
btr_cur_upd_rec_sys(),
page_delete_rec_list_end(),
rtr_page_copy_rec_list_end_no_locks(),
rtr_page_copy_rec_list_start_no_locks(): Return an error code on failure.

fil_space_t::io(), buf_page_get_low(): Use DB_CORRUPTION for
out-of-bounds page reads.

PageBulk::getSplitRec(), PageBulk::copyOut(): Simplify the code.

btr_validate_level(): Prevent some more CHECK TABLE crashes on
corrupted pages.

btr_block_get(), btr_pcur_move_to_next_page(): Implement some checks that
were previously only part of IndexPurge::next().

IndexPurge::next(): Use btr_pcur_move_to_next_page().

0 files changed, 0 insertions, 0 deletions