On Sep 25 2018, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > On Tue, Sep 25, 2018 at 10:30 AM, Nikolaus Rath <Nikolaus@xxxxxxxx> wrote: >> On Sep 24 2018, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >>> 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). >> >> >> You mean sync(2)/syncfs(2), not fsync(), right? Unless my manpages are >> out of date, fsync() only works on a specific inode. > > I would've thought you only need writeback of a specific inode for reflink, no? Aeh, yeah, I did not mention that. Since I couldn't implement real reflink support but have to go through xattrs, my "reflink" also supports reflinking entire directory trees. I guess I could still issue a bunch of fsyncs(), but I think syncfs() is nicer (I can even move it into the client program that sets the magic xattr so that the filesystem does not call into itself). Best, -Nikolaus -- GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F »Time flies like an arrow, fruit flies like a Banana.«