Hi, This has been on my TODO list for a while, and now that ext4 supports parallel dio writes as well, time to dust it off and send it out... This adds an FMODE flag to inform users that a given file supports parallel dio writes. io_uring can use this to avoid serializing dio writes upfront, in case it isn't needed. A few details in patch #2, patch 1 does nothing by itself. -- Jens Axboe