On Thu, Oct 25, 2018 at 1:54 AM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia
> <olga.kornievskaia@xxxxxxxxx> wrote:
> >
> > From: Olga Kornievskaia <kolga@xxxxxxxxxx>
> >
> > VFS copy_file_range was relaxed to allow for cross-device copy.
> > Add a check for now, to disallow cross-device copy offload until
> > appropriate support is added.
> >
> > Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> > `
> > ---
> > fs/overlayfs/file.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
> > index aeaefd2..5282853 100644
> > --- a/fs/overlayfs/file.c
> > +++ b/fs/overlayfs/file.c
> > @@ -483,6 +483,9 @@ static ssize_t ovl_copy_file_range(struct file *file_in, loff_t pos_in,
> > struct file *file_out, loff_t pos_out,
> > size_t len, unsigned int flags)
> > {
> > + if (file_in->f_inode->i_sb != file_out->f_inode->i_sb)
> > + return -EXDEV;
> >
>
> Note that this could be relaxed later on to same fs type
> allowing for cross container copy_file_range() to be performced
> as clone_file_range() when upper is a shared fs with clone support.
>
> Don't worry about it though, I can make this change later after testing
> the use case.
>
> As long as this patch comes in the series *before* relaxing the VFS check,
> You may add:
> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Thank you. I will reorder the patches and yes I thought the individual
FS maintainers/folks would relax the check according to their
functionality. This patch just provides same semantics with respect to
the cross device checking but at the driver level.
>
> Thanks,
> Amir.
