> Date: Tue, 6 Sep 2022 01:16:47 +0000
> From: Klemens Nanni <[email protected]>
>
> The installer considers a disk a root disk if 'a' is FFS and contains
> expected files.
>
> Furthermore, unattended upgrades will always install to the first root
> disk that is found.
>
> This works fine on machines with only one root disk, but it quickly
> behaves unexpectedly when having multiple disks/installations in one
> machine.
>
> I run such machines, esp. since fiddling with softraid and installboot.
>
>
> The installer/sysupgrade experience can definitely be improved here, but
> that takes some consideration.
>
> One requirement, imho, is knowing
> 1. which disk we booted from, i.e.
> from which disk the kernel (/bsd.rd or /bsd.upgrade) was loaded
> 2. which disk the root filesystem is on, i.e.
> likely the same disk holding /home where sysupgrade put the sets
>
>
> The boot disk could be helpful inside installer, e.g. to check if
> /bsd.ugpraded was booted from a valid root disk -- a good indicator for
> rebooting from the same disk the user just ran sysupgrade on.
>
> The root disk is of no help inside the installer as that will always be
> the ramdisk. But it could be used by sysupgrade to perhaps prefill
> /auto_upgrade.conf to decide up-front which disk to upgrade.
> This answer to the 'Which disk is the root disk' question is currently
> answered inside the installer during unattended upgrades... and it will
> always be the first valid root disk, which is not always correct.
>
> So to make progress, here's a diff that exports readily available
> disklabel DUIDs:
>
> # disklabel sd0 | grep duid
> duid: 98c0c47c3ffddeb4
> # sysctl hw | grep duid
> hw.bootduid=98c0c47c3ffddeb4
> hw.rootduid=98c0c47c3ffddeb4
>
> Having that, working out the installer/sysupgrade bits should be easier.
>
> I'm testing this on arm64 with two disks/installations.
>
> Feedback? Objection? OK?
Wouldn't it make more sense to export these as CTLTYPE_QUAD? Or does
that bring endian-ness issues that we'd rather avoid?
> Index: kern/kern_sysctl.c
> ===================================================================
> RCS file: /mount/openbsd/cvs/src/sys/kern/kern_sysctl.c,v
> retrieving revision 1.406
> diff -u -p -r1.406 kern_sysctl.c
> --- kern/kern_sysctl.c 16 Aug 2022 13:29:52 -0000 1.406
> +++ kern/kern_sysctl.c 5 Sep 2022 09:51:38 -0000
> @@ -762,6 +762,12 @@ hw_sysctl(int *name, u_int namelen, void
> case HW_SMT:
> return (sysctl_hwsmt(oldp, oldlenp, newp, newlen));
> #endif
> + case HW_BOOTDUID:
> + return (sysctl_rdstring(oldp, oldlenp, newp,
> + duid_format(bootduid)));
> + case HW_ROOTDUID:
> + return (sysctl_rdstring(oldp, oldlenp, newp,
> + duid_format(rootduid)));
> default:
> return sysctl_bounded_arr(hw_vars, nitems(hw_vars), name,
> namelen, oldp, oldlenp, newp, newlen);
> Index: sys/sysctl.h
> ===================================================================
> RCS file: /mount/openbsd/cvs/src/sys/sys/sysctl.h,v
> retrieving revision 1.229
> diff -u -p -r1.229 sysctl.h
> --- sys/sysctl.h 16 Aug 2022 13:29:53 -0000 1.229
> +++ sys/sysctl.h 5 Sep 2022 09:53:13 -0000
> @@ -931,7 +931,9 @@ struct kinfo_file {
> #define HW_SMT 24 /* int: enable SMT/HT/CMT */
> #define HW_NCPUONLINE 25 /* int: number of cpus being
> used */
> #define HW_POWER 26 /* int: machine has wall-power
> */
> -#define HW_MAXID 27 /* number of valid hw ids */
> +#define HW_BOOTDUID 27 /* string: DUID of boot disk */
> +#define HW_ROOTDUID 28 /* string: DUID of root disk */
> +#define HW_MAXID 29 /* number of valid hw ids */
>
> #define CTL_HW_NAMES { \
> { 0, 0 }, \
> @@ -961,6 +963,8 @@ struct kinfo_file {
> { "smt", CTLTYPE_INT }, \
> { "ncpuonline", CTLTYPE_INT }, \
> { "power", CTLTYPE_INT }, \
> + { "bootduid", CTLTYPE_STRING }, \
> + { "rootduid", CTLTYPE_STRING }, \
> }
>
> /*
>
>
