On Mon, Sep 24, 2018 at 10:02 AM, Nikolaus Rath <Nikolaus@xxxxxxxx> wrote: > Hi, > > How do I trigger writeback from a (writeback-cache enabled) FUSE > filesystem? No way, currently (well, triggering fsync(2)/fdatasync(2) on the filesystem would work, but such recursion is considered highly hackish). I'm working on new interfaces that will allow, among other things, triggering sync from the server. > Background: I am emulating the reflink ioctl with a magic xattr, but for > that to work the filesystem needs to have all the data that is supposed > to be in the copied file. Have a look at the copyfile patch on the for-next branch of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git Adding reflink support based on that should be pretty simple (and it takes care of flushing dirty pages). Thanks, Miklos
