On Mon, Aug 20, 2018 at 6:47 PM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>
> On Mon, Aug 20, 2018 at 6:21 PM Luis Henriques <lhenriques@xxxxxxxx> wrote:
> >
> > Hi!
> >
> > This series is my initial attempt at getting a copy_file_range syscall
> > implementation in the kernel cephfs client using the 'copy-from' RADOS
> > operation.
> >
> > The idea of getting this implemented was from Greg -- or, at least, he
> > created a feature in the tracker [1]. I just decided to give it a try
> > as the feature wasn't assigned to anyone ;-)
> >
> > I have this patchset sitting on my laptop for a while already, waiting
> > for me to revisit it, review some of its TODOs... but I finally decided
> > to send it out as-is instead, to get some early feedback.
> >
> > The first patch implements the copy-from operation in the libceph
> > module. Unfortunately, the documentation for this operation is
> > nonexistent and I had to do a lot of digging to figure out the details
> > (and I probably I missed something!). For example, initially I was
> > hoping that this operation could be used to copy more than one object at
> > the time. Doing an OSD request per object copy is not ideal, but
> > unfortunately it seems to be the only way. Anyway, my expectations are
> > that this new operation will be useful for other features in the future.
>
> A single OSD request can contain multiple OSD ops. In the kernel
> client, this number is currently limited to 16 (CEPH_OSD_MAX_OPS).
... that operate on the same object, so this isn't very relevant.
Thanks,
Ilya
