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From:   Olga Kornievskaia <olga.kornievskaia@gmail.com>
Date:   Sat, 1 Dec 2018 08:44:24 -0500
Message-ID: <CAN-5tyFwE=5K4vCfjVLsyjgOfmLwQU9c-gwJHKedAwOoVWmQ=A@mail.gmail.com>
Subject: Re: [PATCH v2 01/10] VFS generic copy_file_range() support
To:     Amir Goldstein <amir73il@gmail.com>
Cc:     "J. Bruce Fields" <bfields@redhat.com>,
        linux-nfs <linux-nfs@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, david@fromorbit.com,
        willy@infradead.org, jlayton@kernel.org, stfrench@microsoft.com
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Sender: linux-nfs-owner@vger.kernel.org
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On Sat, Dec 1, 2018 at 8:23 AM Olga Kornievskaia
<olga.kornievskaia@gmail.com> wrote:
>
> On Sat, Dec 1, 2018 at 3:11 AM Amir Goldstein <amir73il@gmail.com> wrote:
> >
> > On Fri, Nov 30, 2018 at 10:04 PM Olga Kornievskaia
> > <olga.kornievskaia@gmail.com> wrote:
> > >
> > > Relax the condition that input files must be from the same
> > > file systems.
> > >
> > > Add checks that input parameters adhere semantics.
> > >
> > > If no copy_file_range() support is found, then do generic
> > > checks for the unsupported page cache ranges, LFS, limits,
> > > and clear setuid/setgid if not running as root before calling
> > > do_splice_direct(). Update atime,ctime,mtime afterwards.
> > >
> > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> > > ---
> >
> > This patch is either going to bring you down or make you stronger ;-)
> >
> > This is not how its done. Behavior change and refactoring mixed into
> > one patch is wrong for several reasons. And when you relax same sb
> > check you need to restrict it inside filesystems, like your previous patch
> > did.
> >
> > You already had v7 patch reviewed-by 4 developers.
> > What made you go and change it (and posted as v2)?
> >
> > Your intentions were good trying to fix the broken syscall, but
> > I hope you understood that Dave didn't mean that you *have* to
> > add the missing generic checks as part of your work. He just
> > pointed out how broken the current interface is in the context of
> > reviewing your patch.
> >
> > In any case, I hear that Dave is neck deep in fixing copy_file_range()
> > so changes to this function should be collaborated with him. Or better
> > yet, wait until he posts his fixes and carry on from there.
> >
> > If I were you, I would just go back to the reviewed v7 vfs patch.
>
> This is NOT a replacement to the v7 vfs patch??? This is a new patch
> on top of that one.
>
> I assume that v7 patch has been OK-ed by everybody and is ready to go in???
>
> As you recall, what was left is to provide the functionality to relax
> the check for the superblocks to be the same before calling the
> do_splice_direct(). This patch attempt do this. I was under the
> impression that to do so extra checks were needed to be added which I
> added.
>

To clarify, previously I had a VFS patch with the client-side series
to support "server to server" copy offload. It needed the
functionality to be able to call copy_file_range with different super
blocks.

This patch series is for the server side support for the "server to
server" copy offload. It requires ability to call copy_file_range()
and do a copy between NFS and a local file system. Thus it needs
generic_copy_file_range.

>
> >
> > Thanks,
> > Amir.