Re: [PATCH 5/7] ovl: Set OVL_METACOPY flag during ovl_lookup()

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Oct 04, 2017 at 10:48:36AM +0300, Amir Goldstein wrote:

[..]
> > Ok. Before I dive into details of that patch, I have a concern about
> > creating index of all regular files and verifying them on mount time. Will
> > this lead to excessive mount time overhead for a large index. I mean
> > in container land, people do mount/unmount of container roots very
> > frequently. And paying this verification cost on every mount, can soon
> > start showing up and become a concern.
> 
> Vivek,
> 
> That is a valid concern.
> Counter proposal:
> 
> Have metacopy depend on index=on but not index every regular file.
> 
> This way you still get the assurance that you cannot set inconsistent
> origins to 2 broken hardlinks of the same origin, which would break
> future mount with index=on.
> 
> So counter to what I wrote earlier, has_upper_alias AND !index will
> be a valid state.
> If you find in lookup an upper with METACOPY and no/stale origin
> you return ESTALE.

Ok, I will post V2 patches and return -ESTALE if metacopy xattr is present
but origin could not be found/resolved during lookup.

Vivek