On Thu, Sep 22, 2016 at 02:31:43PM +0200, Jan Kara wrote: > > So I think what Christoph meant in this case is something like attached > patch. That achieves more than your dirty hack in a much cleaner way. > Beware, the patch is only compile-tested. Your patch also disables dioread_nolock (which is what I think Christoph was asking about because it's the rest of the dioread nolock support code which causes the eye-bleeding complexity on the write path). > Then there is the case of unlocked direct IO overwrites which we allow to > run without inode_lock in dioread_nolock mode as well and that is more > difficult to resolve (there lay the problems with blocksize < pagesize you > speak about). Right, by disabling dioread_nolock, it means we lose the feature that dioread_nolock doesn't require blocking versus _any_ direct I/O writes (because of the post-write uninit->init conversion) --- not just DIO overwrites. But we should be able to support dioread_nolock as well as by only taking inode_lock_shared() in the non-dioread_nolock case, I think. Thanks for the prototype patch; I agree it's a cleaner way to go. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
