On Mon, Nov 18, 2019 at 08:12:39AM -0500, Jeff Layton wrote:
> On Mon, 2019-11-18 at 12:09 +0000, Luis Henriques wrote:
> > Hi,
> >
> > Before going ahead with a pull-request for ceph I would like to make sure
> > we're all on the same page regarding the final fix for this problem.
> > Thus, following this email, I'm sending 2 patches: one for ceph OSDs and
> > the another for the kernel client.
> >
> > * osd: add new 'copy-from-notrunc' operation
> > This patch shall be applied to ceph master after reverting commit
> > ba152435fd85 ("osd: add flag to prevent truncate_seq copy in copy-from
> > operation"). It adds a new operation that will be exactly the same as
> > the original 'copy-from' operation, but with the extra 2 parameters
> > (truncate_{seq,size})
> >
> > * ceph: switch copy_file_range to 'copy-from-notrunc' operation
> > This will make the kernel client use the new OSD op in
> > copy_file_range. One extra thing that could probably be added is
> > changing the mount options to NOCOPYFROM if the first call to
> > ceph_osdc_copy_from() fails.
> >
>
> I probably wouldn't change the mount options to be different from what
> was initially specified. How about just disable copy_file_range
> internally for that superblock, and then pr_notice a message that says
> that copy_file_range is being autodisabled. If they mount with '-o
> nocopyfrom' that will make the warning go away.
Ok, that makes sense. I'll include this in the next rev, which will
probably be sent only after the pull-request for ceph goes in (assuming
the OSD patch won't need any major rework).
> > Does this look good, or did I missed something from the previous
> > discussion?
> >
> > (One advantage of this approach: the OSD patch can be easily backported!)
> >
>
> Yep, I think this looks like a _much_ simpler approach to the problem.
Agreed!
Cheers,
--
Luís
