On Mon, Oct 31, 2022 at 02:18:40AM +0100, Thomas Weißschuh wrote: > Hi all, > > I just tried to run the unittests of bcachefs-tools and they are failing for > me. > The culprit is that mkfs.bcachefs tries to open the disk image with O_DIRECT > which is not allowed on tmpfs. > > Is O_DIRECT really necessary for mkfs? It does not seem necessary for other > filesystems. Hey - the proper mailing list for bcachefs is linux-bcachefs@xxxxxxxxxxxxxxx now :) It's not strictly necessary, we use O_DIRECT because we're emulating the kernel bio interface. There are other situations where this has been a problem though, we need to add either a flag to use buffered IO or preferably a way to automatically fall back to buffered IO. Could you open a bug for this? I'll try to get to it in the near future https://github.com/koverstreet/bcachefs/issues/ Cheers, Kent
