Re: [PATCH 7/7] ovl: Fix ovl_getattr() to get size from lower

[Vivek Goyal <vgoyal@redhat.com>]

On Mon, Oct 02, 2017 at 10:40:07PM +0300, Amir Goldstein wrote:
> On Mon, Oct 2, 2017 at 4:40 PM, Vivek Goyal <vgoyal@redhat.com> wrote:
> > If an inode has been copied up metadata only, then we need to query the
> > size from lower and fill up the stat->size.
> 
> So you won't need this patch if you copy st_size on metadata_copy,
> which seems like the logical thing to do.
> Thinking very far into the future when METACOPY and ORIGIN will
> be able to share page mappings, they will have to start with the same size.

Hi Amir,

What about "st_blocks"? After metadata copy up, doing stat on overlay file
shows "st_blocks" as 0. I think I still will need to intervene and get
st_blocks from lower file instead?

Vivek

> 
> >
> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> > ---
> >  fs/overlayfs/inode.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> > index e5825b8948e0..1b676deacc2d 100644
> > --- a/fs/overlayfs/inode.c
> > +++ b/fs/overlayfs/inode.c
> > @@ -140,6 +140,16 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
> >         if (!is_dir && ovl_test_flag(OVL_INDEX, d_inode(dentry)))
> >                 stat->nlink = dentry->d_inode->i_nlink;
> >
> > +       if (ovl_test_flag(OVL_METACOPY, d_inode(dentry))) {
> > +               struct kstat lowerstat;
> > +               u32 lowermask = STATX_SIZE;
> > +
> > +               ovl_path_lower(dentry, &realpath);
> > +               err = vfs_getattr(&realpath, &lowerstat, lowermask, flags);
> > +               if (err)
> > +                       goto out;
> > +               stat->size = lowerstat.size;
> > +       }
> >  out:
> >         revert_creds(old_cred);
> >
> > --
> > 2.13.5
> >