ext4: Clear dirty bit from pages without data to write

ext4: Clear dirty bit from pages without data to write

With journalled data it can happen that checkpointing code will write
out page contents without clearing the page dirty bit. The logic in
ext4_page_nomap_can_writeout() then results in us never calling
mpage_submit_page() and thus clearing the dirty bit. Drop the
optimization with ext4_page_nomap_can_writeout() and just always call to
mpage_submit_page(). ext4_bio_write_page() knows when to redirty the
page and the additional clearing & setting of page dirty bit for ordered
mode writeout is not that expensive to jump through the hoops for it.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230329154950.19720-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>