ext4: add large folios support for moving extents

ext4: add large folios support for moving extents

Pass the moving extent length into mext_folio_double_lock() so that it
can acquire a higher-order folio if the length exceeds PAGE_SIZE. This
can speed up extent moving when the extent is larger than one page.
Additionally, remove the unnecessary comments from
mext_folio_double_lock().

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-ID: <20251013015128.499308-12-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>