On Thu, Sep 27, 2018 at 7:23 AM, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Wed, Sep 26 2018 at 3:16am -0400, > Richard Weinberger <richard.weinberger@xxxxxxxxx> wrote: > >> Helen, >> >> On Wed, Sep 26, 2018 at 7:01 AM Helen Koike <helen.koike@xxxxxxxxxxxxx> wrote: >> > >> > This series is reviving an old patchwork. >> > Booting from a mapped device requires an initramfs. This series is >> > allows for device-mapper targets to be configured at boot time for >> > use early in the boot process (as the root device or otherwise). >> >> What is the reason for this patch series? >> Setting up non-trivial root filesystems/storage always requires an >> initramfs, there is nothing >> wrong about this. > > Exactly. If phones or whatever would benefit from this patchset then > say as much. I think some of the context for the series was lost in commit logs, but yes, both Android and Chrome OS do not use initramfs. The only thing that was needed to do this was being able to configure dm devices on the kernel command line, so the overhead of a full initramfs was seen as a boot time liability, a boot image size liability (e.g. Chrome OS has a limited amount of storage available for the boot image that is covered by the static root of trust signature), and a complexity risk: everything that is needed for boot could be specified on the kernel command line, so better to avoid the whole initramfs dance. So, instead, this plumbs the dm commands directly instead of bringing up a full userspace and performing ioctls. > I will not accept this patchset at this time. > >> > Example, the following could be added in the boot parameters. >> > dm="lroot,,,rw, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" root=/dev/dm-0 >> >> Hmmm, the new dm= parameter is anything but easy to get right. > > No, it isn't.. exposes way too much potential for users hanging > themselves. IIRC, the changes in syntax were suggested back when I was trying to drive this series: https://www.redhat.com/archives/dm-devel/2016-February/msg00199.html And it matches the "concise" format in dmsetup: https://sourceware.org/git/?p=lvm2.git;a=commit;h=827be01758ec5adb7b9d5ea75b658092adc65534 What do you feel are next steps? Thanks! -Kees -- Kees Cook Pixel Security -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
