On 05/02/2016 09:48 PM, Dan Williams wrote: <> >> And then it keeps broken the aligned buffered writes, which are still >> broken after this set. > > ...identical to the current situation with a traditional disk. > Not true!! please see what I wrote "aligned buffered writes" If there are no reads involved then there are no errors returned to application. >> I have by now read the v2 patches. And I think you guys did not yet try >> the proper fix for dax_do_io. I think you need to go deeper into the loops >> and selectively call bdev_* when error on a specific page copy. No need to >> go through direct_IO path at all. > > We still reach a point where the minimum granularity of > bdev_direct_access() is larger than a sector, so you end up still > needing to have the application understand how to send a properly > aligned I/O. The semantics of how to send a properly aligned > direct-I/O are already well understood, so we simply reuse that path. > You are making a mountain out of a mouse. The simple copy of a file from start (offset ZERO) to end-of-file which is the most common usage on earth is perfectly aligned and needs not any O_DIRECT and is what is used everywhere. >> Do you need that I send you a patch to demonstrate what I mean? > > I remain skeptical of what you are proposing, but yes, a patch has a > better chance to move the discussion forward. > Sigh! OK Boaz -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>