From: Robert Yang <liezhi.yang@windriver.com>
To: Bruce Ashfield <bruce.ashfield@gmail.com>
Cc: Patches and discussions about the oe-core layer
<openembedded-core@lists.openembedded.org>
Subject: Re: [PATCH 1/1] linux-yocto 4.4: enable overlayfs by default
Date: Tue, 5 Apr 2016 17:06:24 +0800 [thread overview]
Message-ID: <57038010.8040501@windriver.com> (raw)
In-Reply-To: <CADkTA4Ojrn5DddPnAK2Ss6k0F2E+i5r0f68jN7F49WTAFa6pEg@mail.gmail.com>
On 04/05/2016 04:33 PM, Bruce Ashfield wrote:
>
>
> On Tue, Apr 5, 2016 at 2:42 AM, Robert Yang <liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>> wrote:
>
>
>
> On 04/05/2016 02:33 PM, Bruce Ashfield wrote:
>
>
>
> On Mon, Apr 4, 2016 at 10:48 PM, Robert Yang <liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>
> <mailto:liezhi.yang@windriver.com <mailto:liezhi.yang@windriver.com>>>
> wrote:
>
>
>
> On 04/05/2016 10:31 AM, Bruce Ashfield wrote:
>
>
>
> On Mon, Apr 4, 2016 at 9:53 PM, Robert Yang
> <liezhi.yang@windriver.com <mailto:liezhi.yang@windriver.com>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>>>>
> wrote:
>
>
> 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.
>
>
> That sort of mechanism can work, but not if it is enabled by
> default.
> out of box
> experience
> is one thing, but there are plenty of boot and image types that
> don't need a
> unionfs, and
> we can't force these as =y for those image types.
>
> If we make a modular config, and a built-in config, we could
> pick the
> modular
> config by
> default, and then have the package list for the images that
> need them,
> rdepend
> on the
> appropriate modules.
>
>
> Sounds good, so how about:
>
> 1) Update kernel to make overlayfs as module rather than builtin
>
>
> Having two fragments make sense. one for built in, and one that is modules.
> Since these are
> distinct use case both sets of configuration are reasonable.
>
>
> How about this:
>
> diff --git a/ktypes/preempt-rt/preempt-rt.cfg b/ktypes/preempt-rt/preempt-rt.cfg
> index 4c62804..28ad8cf 100644
> --- a/ktypes/preempt-rt/preempt-rt.cfg
> +++ b/ktypes/preempt-rt/preempt-rt.cfg
> @@ -1116,3 +1116,5 @@ CONFIG_CRYPTO_TEST=m
> #
> CONFIG_LIBCRC32C=m
> CONFIG_ZLIB_DEFLATE=m
> +
> +CONFIG_OVERLAY_FS=m
> diff --git a/ktypes/standard/standard.cfg b/ktypes/standard/standard.cfg
> index b3dbde5..3dabf49 100644
> --- a/ktypes/standard/standard.cfg
> +++ b/ktypes/standard/standard.cfg
> @@ -1108,3 +1108,5 @@ CONFIG_LIBCRC32C=m
> CONFIG_ZLIB_DEFLATE=m
>
> CONFIG_SHMEM=y
> +
> +CONFIG_OVERLAY_FS=m
>
>
> Nope. See my follow up to the linux-yocto patch .. I was more detailed in my
> follow up
> there.
I read that just now, if we don't enable the module in oe-core layer or
builtin it, I'm fine to leave the live image (iso, hddimg) broken by
default and document that if you need a read write live image and fix
the errors, you can enable it from KERNEL_FEATURES ?
>
>
>
> 2) let core-image-minimal-initramfs RDEPENEDS on the module.
>
>
> I'd still prefer that this be set in a distro or optional layer. Since why
>
>
> The live/iso/hddimg is supported by oe-core, all of them are in oe-core layer,
> I'm afraid that we can't add it in an extra layer or bbappend.
>
>
> Why not ? There are just as many image types that don't need this support. Why
> should
> it be universally build and enabled for a feature that is only used by some boot
> types.
>
> You are missing the point, and there's no justification to globally enable it.
>
> What about flash boot, what about boot from specific MTD devices, etc, etc, should
> they all be enabled by default in the base configs .. just in case someone boots
> that
> way ? We'll end up with a giant kernel with everything enabled or as modules if we
> cover all the cases. These need to be specifically requested and triggered.
>
> Just because you are concerned with live iso boot, doesn't mean that others are,
> and that we should have the overhead everywhere.
>
>
> should core image
> minimal be the target for this ? There are any number of targets that
> might be
> used for
> live boot.
>
>
> All of them are in oe-core layer, core-image-minimal-initramfs.bb
> <http://core-image-minimal-initramfs.bb> is the
> default live image in oe-core, I think that add kerne-module-overlay to
> its INSTALL is reasonable.
>
>
> But that shouldn't need overlayfs for all configs. I boot initramfs kernels all
> the time, I have no need
> for overlay filesystems on those boards.
>
> But yes, if you enable a module based overlayfs fragment, and then install the
> module via an install, it should be ok, since it can be overridden.
Did you mean it in oe-core or out of oe-core such as an external layer or
bbappend, please ?
>
> I hope you are seeing the point of not enabling kernel options "just in case",
> and why
> this sort of thing needs to be only built and installed when it is truly needed.
I'm sorry, but I don't think that this is a "just in case" issue, live image
is officially supported by oe-core, I think that we should release a workable
image to the user rather than a half-finished one, currently, for example,
the obvious errors when boot:
Populating dev cache
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/rcS.d/S36udev-cache: line 73: can't create /etc/udev-cache.tar.gz:
Read-only file system
udev-cache: update failed!
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
rm: can't remove '/etc/udev/cache.data': Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
rm: can't remove '/tmp': Read-only file system
ln: /tmp/tmp: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
ln: /etc/resolv.conf: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
/etc/init.d/rc: /etc/rcS.d/S37populate-volatile.sh: line 1: can't create
/etc/volatile.cache.build: Read-only file system
And it's readonly, the user can change nothing on the system when debug.
// Robert
>
> Bruce
>
>
> If there are other layers which have their own live image, then they can add
> it to their INSTALL.
>
>
> // Robert
>
>
> Bruce
>
> // Robert
>
>
> Bruce
>
>
> // 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>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>>>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>>
> <mailto:richard.purdie@linuxfoundation.org
> <mailto:richard.purdie@linuxfoundation.org>
> <mailto: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>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>>>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>
> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>> <mailto:liezhi.yang@windriver.com
> <mailto:liezhi.yang@windriver.com>
> <mailto: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"
>
>
>
>
> --
> "Thou shalt not follow the NULL pointer, for chaos and madness
> await
> thee at its
> end"
>
>
>
>
> --
> "Thou shalt not follow the NULL pointer, for chaos and madness await
> thee at its
> end"
>
>
>
>
> --
> "Thou shalt not follow the NULL pointer, for chaos and madness await thee at its
> end"
next prev parent reply other threads:[~2016-04-05 9:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-03 9:58 [PATCH 0/1 V2] linux-yocto 4.4: enable overlayfs by default Robert Yang
2016-04-03 9:58 ` [PATCH 1/1] " Robert Yang
2016-04-03 10:11 ` Bruce Ashfield
2016-04-03 21:46 ` Richard Purdie
2016-04-03 23:56 ` Bruce Ashfield
2016-04-05 1:53 ` Robert Yang
2016-04-05 2:31 ` Bruce Ashfield
2016-04-05 2:48 ` Robert Yang
2016-04-05 6:33 ` Bruce Ashfield
2016-04-05 6:42 ` Robert Yang
2016-04-05 8:33 ` Bruce Ashfield
2016-04-05 9:06 ` Robert Yang [this message]
2016-04-05 14:59 ` Bruce Ashfield
2016-04-03 10:00 ` [PATCH 0/1 V2] " Robert Yang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=57038010.8040501@windriver.com \
--to=liezhi.yang@windriver.com \
--cc=bruce.ashfield@gmail.com \
--cc=openembedded-core@lists.openembedded.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.