> If filetypes speed up Linux then I don't see why I should leave > them out, even if they slow down fsck. Or do they need extra > space on the disk?
What is it you think is sped up by having the field? Its only use (as far as I know, not having Linux source handy this moment to check) is to report in the d_type field of struct dirent. Few if any programs make use of this, maybe find does. It's not so much that it slows down e2fsck, it's that you get all those messages saying "foo is wrong, fixing it" and people tend to freak out when they see such things from fsck (especially zillions of them flying by), and then they report the "bug" here (again). The filetype field occupies one byte in each directory entry, and that byte is always zero in the absence of the filetype feature (it's the high-order byte of the name length, and the name is otherwise constrained to be short enough to have its length fit in just the low-order byte).