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.
> 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.
--
Jeff Layton <jlayton@xxxxxxxxxx>
