ext4: support large block size in mpage_prepare_extent_to_map()

ext4: support large block size in mpage_prepare_extent_to_map()

Use the EXT4_PG_TO_LBLK/EXT4_LBLK_TO_PG macros to complete the conversion
between folio indexes and blocks to avoid negative left/right shifts after
supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-20-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>