Re: [PATCH 1/1] linux-yocto 4.4: enable overlayfs by default

[Robert Yang <liezhi.yang@windriver.com>]

Hi Bruce,

How many union fs on Linux, please? AFAIK:
* unionfs: not supported by kernel any more.
* aufs
* overlayfs

If aufs and overlayfs are conflicted, how about:

KERNEL_UNION_FS ?= "features/overlayfs/overlayfs.scc"

KERNEL_EXTRA_FEATURES ?= "[snip] ${KERNEL_UNION_FS}"

I think that we really need a way to make iso/hddimg work by default
to enhance the OOBE.

// Robert

On 04/04/2016 07:56 AM, Bruce Ashfield wrote:
>
>
> On Sun, Apr 3, 2016 at 5:46 PM, Richard Purdie
> <richard.purdie@linuxfoundation.org <mailto:richard.purdie@linuxfoundation.org>>
> wrote:
>
>     On Sun, 2016-04-03 at 06:11 -0400, Bruce Ashfield wrote:
>     >
>     >
>     > On Sun, Apr 3, 2016 at 5:58 AM, Robert Yang <
>     >liezhi.yang@windriver.com <mailto:liezhi.yang@windriver.com>> wrote:
>     > > So that iso can work well, otherwise the iso is readonly and there
>     > > would
>     > > be errors. The other way is aufs, but overlayfs is more pupolar and
>     > > had
>     > > been merged by kernel mainline, we need make iso work well by
>     > > default.
>     > Nope. As I mentioned before, this can't be a always on default. It
>     > will conflict
>     > with other unionFS use cases.
>     >
>     > If you want overlayfs enabled, it needs to be triggered from a
>     > specific image
>     > or distro feature.
>
>     We can't change the kernel config from an image so it would have to be
>     a distro setting. Is there a problem with enabling both as modules btw?
>     I assume they can coexist?
>
>
> I've always found it limiting that we can't trigger kernel features based on
> what an image'
> type actually needs, but I understand why/how it works like this.
>
> If it can't be triggered by an image setting, then just keeping a layer that is
> added
> to the build, that has a bbappend with the appropriate KERNEL_FEATURES would
> also work, and is the approach that I've also taken.
>
> Not that the existing configs are great in this respect (they need a lot of
> streamlining),
> but building modules 'just in case' eventually leads to allmodconfig :)
>
> I'd imagine they could co-exist, but it isn't something I've tried.
>
> Bruce
>
>
>     Cheers,
>
>     Richard
>
>
>
>
> --
> "Thou shalt not follow the NULL pointer, for chaos and madness await thee at its
> end"