syzbot is reporting hung task at do_user_addr_fault() [1], for there is
a silent deadlock between PG_locked bit and ni_lock lock.
Since filemap_update_page() calls filemap_read_folio() after calling
folio_trylock() which will set PG_locked bit, ntfs_truncate() must not
call truncate_setsize() which will wait for PG_locked bit to be cleared
when holding ni_lock lock.