Re: [PATCH] distroboot: Fix ubifs

Alexander Dahl
2022-06-30T06:47:09Z

Hello,

Am Mittwoch, 29. Juni 2022, 15:55:27 CEST schrieb Pali Rohár:
> Hello!
>
> On Wednesday 29 June 2022 15:36:57 Alexander Dahl wrote:
> > Hello Pali,
> >
> > had a look at this patch, and have some questions. See below.
> >
> > Am Dienstag, 31. Mai 2022, 10:32:36 CEST schrieb Pali Rohár:
> > > Fix multiple issues in ubifs distroboot code:
> > >
> > > U-Boot supports attaching only one MTD device as UBI at the time. So
> > > always call 'ubifsmount ubi0:${bootubivol}' for mounting UBI volume
> > > ${bootubivol}. Usage of 'ubi${devnum}' is incorrect as 'ubi part'
> > > command attach MTD device always as UBI device ubi0.
> >
> > Agreed.
> >
> > > Set distroboot ${bootfstype} variable to ubifs in ubifs_boot command.
> > > Distroboot scripts require ${bootfstype} variable to be properly set and
> > > it
> > > is already set for all other boot types.
> >
> > From grepping through u-boot source, I can not quite follow. Where is
> > that
> > variable set and where is it used?
>
> For non-ubifs boot targets, env variable ${bootfstype} is set by
> scan_dev_for_boot_part shell fragment. Then it calls user boot script
> which can use ${bootfstype} variable. In most cases it is used for
> constructing cmdline for kernel, mainly as "roofstype=${bootfstype}".

So this is no variable stored in env, but used in scripts only, right?
Especially in scripts not part of U-Boot itself? Maybe this should be
documented somewhere then?

> > > Set distroboot ${distro_bootpart} variable to ${bootubivol} value. UBI
> > > device does not have partitions, but has volumes. Distroboot scripts
> > > require something to be set in ${distro_bootpart} variable, so set it to
> > > the UBI volume which is currently mounted by ubifs.
> > >
> > > Set distroboot ${devnum} variable to fixed string "ubi0". ubifs code
> > > differs from the other partition code that it requires "ubi" prefix
> > > before
> > > number.
> >
> > Okay.
> >
> > > Explicitly unmount ubifs volume after loading all data from it. This
> > > allows
> > > to detach UBI device from MTD device.
> >
> > Okay.
> >
> > > Move definition of MTD device with UBI and UBI volume with ubifs
> > > filesystem
> > > from global env variables ${bootubipart} and ${bootubivol} into the
> > > distroboot "func" macro, defined in board include config files. UBIFS
> > > distroboot macros then set ${bootubipart} and ${bootubivol} local
> > > variables
> > > for compatibility with existing distroboot scripts.
> >
> > This might be problematic. For a downstream board we use the 'bootubivol'
> > env variable to switch between different volumes for update purposes.
> > Means on firmware update we modify U-Boot environment from Linux
> > (fw_setenv) after successfully updating the inactive volume.
>
> Interesting... I even did not thought about such use case as it is not
> possible to do it with other boot filesystems.

Well yes, it's somewhat of a hack, but it uses existing distroboot
infrastructure. We did comparable switching of volumes for active rootfs
without distroboot before. On newer targets we use distroboot together with
RAUC and have one fix separate boot volume containing the boot script (the
boot script is not part of those rootfs[01] anymore), which handles loading
one or the other rootfs, no need to alter bootubivol anymore, it's constant.

> > > This last change allows to define more UBIFS target devices and make it
> > > clear what is boot MTD/UBI device.
> >
> > How would one switch the default UBI volume to be booted from then?
>
> With this my change, it is probably not easily possible. One option is
> to define more boot targets, e.g.:
>
> func(UBIFS, ubifs, 0, UBI, volume0)
> func(UBIFS, ubifs, 1, UBI, volume1)
>
> And then change env ${boottargets} from ubifs0 to ubifs1, which can be
> done via fs_setenv.

This should work, yes. Maybe it's a little more complicated than this, e.g.
switching
from 'mmc0 ubifs0' to 'mmc0 ubifs1'
or
from 'ubifs0 ubifs1' to 'ubifs1 ubifs0'
but that's board dependent and no big deal in general I guess.

> As with this change is finally possible to specify more ubifs targets
> in BOOT_TARGET_DEVICES() u-boot macro.
>
> This would be same as switching between other u-boot distroboot targets.

Makes sense.

>
> ...
>
> But I can understand that you want to have this (probably undocumented)
> behavior of switching UBI volume via env variable ${bootubivol}.
>
> So what about allowing both configuration in U-Boot, with stored boot
> volume in ENV and with hardcoded boot volume in config file?

Just had another look at how 'bootcmd_ubifs0' is set with your patch, and I
think with switching 'boot_targets' instead of 'bootubivol' it should work
(not tested). Only problem would be a migration strategy for old boards or a
more sophisticated logic in Linux to determine what env variable has to be
updated, but don't let that be your concern.

> And which / how many boards use this functionality?

Seriously, I have no idea. You never know what all those downstream users do,
especially in this case where functionality is in a boot script not part of U-
Boot itself. Maybe I'm the only one using it like this, maybe not. As of
today I would recommend to use some update framework like RAUC anyways.

Greets
Alex

>
> > Greets
> > Alex
> >
> > > All board include config files are adjusted to use this new scheme of
> > > specifying boot MTD/UBI device.
> > >
> > > Signed-off-by: Pali Rohár <pali@kernel.org>
> > > ---
> > > CI test passed on https://github.com/u-boot/u-boot/pull/179
> > > ---
> > >
> > > include/config_distro_bootcmd.h | 27 ++++++++++++++++-----------
> > > include/configs/am335x_guardian.h | 3 +--
> > > include/configs/colibri-imx6ull.h | 1 -
> > > include/configs/colibri_imx7.h | 1 -
> > > include/configs/kontron-sl-mx6ul.h | 2 +-
> > > include/configs/mys_6ulx.h | 2 +-
> > > include/configs/npi_imx6ull.h | 2 +-
> > > include/configs/omap3_beagle.h | 4 +---
> > > include/configs/omap3_evm.h | 4 +---
> > > include/configs/pcl063.h | 2 +-
> > > include/configs/stm32mp15_common.h | 2 +-
> > > include/configs/uniphier.h | 2 +-
> > > 12 files changed, 25 insertions(+), 27 deletions(-)
> > >
> > > diff --git a/include/config_distro_bootcmd.h
> > > b/include/config_distro_bootcmd.h index c55023889cab..c6e9c497413d
> > > 100644
> > > --- a/include/config_distro_bootcmd.h
> > > +++ b/include/config_distro_bootcmd.h
> > > @@ -70,18 +70,23 @@
> > >
> > > #ifdef CONFIG_CMD_UBIFS
> > > #define BOOTENV_SHARED_UBIFS \
> > >
> > > "ubifs_boot=" \
> > >
> > > - "env exists bootubipart || " \
> > > - "env set bootubipart UBI; " \
> > > - "env exists bootubivol || " \
> > > - "env set bootubivol boot; " \
> > >
> > > "if ubi part ${bootubipart} && " \
> > >
> > > - "ubifsmount ubi${devnum}:${bootubivol}; " \
> > > + "ubifsmount ubi0:${bootubivol}; " \
> > >
> > > "then " \
> > >
> > > "devtype=ubi; " \
> > >
> > > + "devnum=ubi0; " \
> > > + "bootfstype=ubifs; " \
> > > + "distro_bootpart=${bootubivol}; " \
> > >
> > > "run scan_dev_for_boot; " \
> > >
> > > + "ubifsumount; " \
> > >
> > > "fi\0"
> > >
> > > -#define BOOTENV_DEV_UBIFS BOOTENV_DEV_BLKDEV
> > > -#define BOOTENV_DEV_NAME_UBIFS BOOTENV_DEV_NAME_BLKDEV
> > > +#define BOOTENV_DEV_UBIFS(devtypeu, devtypel, instance, bootubipart,
> > > bootubivol) \ + "bootcmd_ubifs" #instance "=" \
> > > + "bootubipart=" #bootubipart "; " \
> > > + "bootubivol=" #bootubivol "; " \
> > > + "run ubifs_boot\0"
> > > +#define BOOTENV_DEV_NAME_UBIFS(devtypeu, devtypel, instance,
> > > bootubipart,
> > > bootubivol) \ + #devtypel #instance " "
> > >
> > > #else
> > > #define BOOTENV_SHARED_UBIFS
> > > #define BOOTENV_DEV_UBIFS \
> > >
> > > @@ -411,13 +416,13 @@
> > >
> > > BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE
> > >
> > > #endif
> > >
> > > -#define BOOTENV_DEV_NAME(devtypeu, devtypel, instance) \
> > > - BOOTENV_DEV_NAME_##devtypeu(devtypeu, devtypel, instance)
> > > +#define BOOTENV_DEV_NAME(devtypeu, devtypel, instance, ...) \
> > > + BOOTENV_DEV_NAME_##devtypeu(devtypeu, devtypel, instance, ##
> > > __VA_ARGS__)
> > >
> > > #define BOOTENV_BOOT_TARGETS \
> > >
> > > "boot_targets=" BOOT_TARGET_DEVICES(BOOTENV_DEV_NAME) "\0"
> > >
> > > -#define BOOTENV_DEV(devtypeu, devtypel, instance) \
> > > - BOOTENV_DEV_##devtypeu(devtypeu, devtypel, instance)
> > > +#define BOOTENV_DEV(devtypeu, devtypel, instance, ...) \
> > > + BOOTENV_DEV_##devtypeu(devtypeu, devtypel, instance, ## __VA_ARGS__)
> > >
> > > #define BOOTENV \
> > >
> > > BOOTENV_SHARED_HOST \
> > > BOOTENV_SHARED_MMC \
> > >
> > > diff --git a/include/configs/am335x_guardian.h
> > > b/include/configs/am335x_guardian.h index b92703205cde..340715dad5c6
> > > 100644
> > > --- a/include/configs/am335x_guardian.h
> > > +++ b/include/configs/am335x_guardian.h
> > > @@ -29,7 +29,7 @@
> > >
> > > "ramdisk_addr_r=0x88080000\0" \
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > - func(UBIFS, ubifs, 0)
> > > + func(UBIFS, ubifs, 0, UBI, rootfs)
> > >
> > > #define AM335XX_BOARD_FDTFILE "fdtfile=" CONFIG_DEFAULT_DEVICE_TREE
> > >
> > > ".dtb\0"
> > >
> > > @@ -54,7 +54,6 @@
> > >
> > > GUARDIAN_DEFAULT_PROD_ENV \
> > > "autoload=no\0" \
> > > "backlight_brightness=50\0" \
> > >
> > > - "bootubivol=rootfs\0" \
> > >
> > > "distro_bootcmd=" \
> > >
> > > "setenv rootflags \"bulk_read,chk_data_crc\"; " \
> > > "setenv ethact usb_ether; " \
> > >
> > > diff --git a/include/configs/colibri-imx6ull.h
> > > b/include/configs/colibri-imx6ull.h index 9e5212acb2ee..a0a0e1767fe0
> > > 100644
> > > --- a/include/configs/colibri-imx6ull.h
> > > +++ b/include/configs/colibri-imx6ull.h
> > > @@ -91,7 +91,6 @@
> > >
> > > UBI_BOOTCMD \
> > > UBOOT_UPDATE \
> > > "boot_script_dhcp=boot.scr\0" \
> > >
> > > - "bootubipart=ubi\0" \
> > >
> > > "console=ttymxc0\0" \
> > > "defargs=user_debug=30\0" \
> > > "fdt_board=eval-v3\0" \
> > >
> > > diff --git a/include/configs/colibri_imx7.h
> > > b/include/configs/colibri_imx7.h index 3dba7bcef258..3cad17777975
> > > 100644
> > > --- a/include/configs/colibri_imx7.h
> > > +++ b/include/configs/colibri_imx7.h
> > > @@ -131,7 +131,6 @@
> > >
> > > UBOOT_UPDATE \
> > > "boot_file=zImage\0" \
> > > "boot_script_dhcp=boot.scr\0" \
> > >
> > > - "bootubipart=ubi\0" \
> > >
> > > "console=ttymxc0\0" \
> > > "defargs=\0" \
> > > "fdt_board=eval-v3\0" \
> > >
> > > diff --git a/include/configs/kontron-sl-mx6ul.h
> > > b/include/configs/kontron-sl-mx6ul.h index 7bc402d578e8..b4808d2bbf75
> > > 100644
> > > --- a/include/configs/kontron-sl-mx6ul.h
> > > +++ b/include/configs/kontron-sl-mx6ul.h
> > > @@ -45,7 +45,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 1) \
> > > func(MMC, mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, UBI, boot) \
> > >
> > > func(USB, usb, 0) \
> > > func(PXE, pxe, na) \
> > > func(DHCP, dhcp, na)
> > >
> > > diff --git a/include/configs/mys_6ulx.h b/include/configs/mys_6ulx.h
> > > index 6801fc109eae..663820177a3e 100644
> > > --- a/include/configs/mys_6ulx.h
> > > +++ b/include/configs/mys_6ulx.h
> > > @@ -59,7 +59,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, UBI, boot) \
> > >
> > > func(PXE, pxe, na) \
> > > func(DHCP, dhcp, na)
> > >
> > > diff --git a/include/configs/npi_imx6ull.h
> > > b/include/configs/npi_imx6ull.h
> > > index c250fa650603..ebb887544e08 100644
> > > --- a/include/configs/npi_imx6ull.h
> > > +++ b/include/configs/npi_imx6ull.h
> > > @@ -67,7 +67,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, UBI, boot) \
> > >
> > > func(PXE, pxe, na) \
> > > func(DHCP, dhcp, na)
> > >
> > > diff --git a/include/configs/omap3_beagle.h
> > > b/include/configs/omap3_beagle.h index 158773acedb9..f5da08cf3359
> > > 100644
> > > --- a/include/configs/omap3_beagle.h
> > > +++ b/include/configs/omap3_beagle.h
> > > @@ -65,7 +65,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 0) \
> > > func(LEGACY_MMC, legacy_mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, rootfs, rootfs) \
> > >
> > > func(NAND, nand, 0)
> > >
> > > #else /* !CONFIG_MTD_RAW_NAND */
> > >
> > > @@ -87,8 +87,6 @@
> > >
> > > "bootenv=uEnv.txt\0" \
> > > "bootfile=zImage\0" \
> > > "bootpart=0:2\0" \
> > >
> > > - "bootubivol=rootfs\0" \
> > > - "bootubipart=rootfs\0" \
> > >
> > > "usbtty=cdc_acm\0" \
> > > "mpurate=auto\0" \
> > > "buddy=none\0" \
> > >
> > > diff --git a/include/configs/omap3_evm.h b/include/configs/omap3_evm.h
> > > index eeb9ef8c741a..cc98e03096ab 100644
> > > --- a/include/configs/omap3_evm.h
> > > +++ b/include/configs/omap3_evm.h
> > > @@ -60,7 +60,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 0) \
> > > func(LEGACY_MMC, legacy_mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, rootfs, rootfs) \
> > >
> > > func(NAND, nand, 0)
> > >
> > > #else /* !CONFIG_MTD_RAW_NAND */
> > >
> > > @@ -88,8 +88,6 @@
> > >
> > > "bootenv=uEnv.txt\0" \
> > > "bootfile=zImage\0" \
> > > "bootpart=0:2\0" \
> > >
> > > - "bootubivol=rootfs\0" \
> > > - "bootubipart=rootfs\0" \
> > >
> > > "optargs=\0" \
> > > "nandroot=ubi0:rootfs ubi.mtd=rootfs rw noinitrd\0" \
> > > "nandrootfstype=ubifs rootwait\0" \
> > >
> > > diff --git a/include/configs/pcl063.h b/include/configs/pcl063.h
> > > index 31b7d07a24cd..c3f7e7eb2c4b 100644
> > > --- a/include/configs/pcl063.h
> > > +++ b/include/configs/pcl063.h
> > > @@ -71,7 +71,7 @@
> > >
> > > #define BOOT_TARGET_DEVICES(func) \
> > >
> > > func(MMC, mmc, 0) \
> > >
> > > - func(UBIFS, ubifs, 0) \
> > > + func(UBIFS, ubifs, 0, UBI, boot) \
> > >
> > > func(PXE, pxe, na) \
> > > func(DHCP, dhcp, na)
> > >
> > > diff --git a/include/configs/stm32mp15_common.h
> > > b/include/configs/stm32mp15_common.h index 6b40cdb01779..68ea56e69c98
> > > 100644
> > > --- a/include/configs/stm32mp15_common.h
> > > +++ b/include/configs/stm32mp15_common.h
> > > @@ -77,7 +77,7 @@
> > >
> > > #endif
> > >
> > > #ifdef CONFIG_CMD_UBIFS
> > >
> > > -#define BOOT_TARGET_UBIFS(func) func(UBIFS, ubifs, 0)
> > > +#define BOOT_TARGET_UBIFS(func) func(UBIFS, ubifs, 0, UBI, boot)
> > >
> > > #else
> > > #define BOOT_TARGET_UBIFS(func)
> > > #endif
> > >
> > > diff --git a/include/configs/uniphier.h b/include/configs/uniphier.h
> > > index f813f88cdd7a..640a29067d85 100644
> > > --- a/include/configs/uniphier.h
> > > +++ b/include/configs/uniphier.h
> > > @@ -20,7 +20,7 @@
> > >
> > > #endif
> > >
> > > #ifdef CONFIG_CMD_UBIFS
> > >
> > > -#define BOOT_TARGET_DEVICE_UBIFS(func) func(UBIFS, ubifs, 0)
> > > +#define BOOT_TARGET_DEVICE_UBIFS(func) func(UBIFS, ubifs, 0, UBI,
boot)
> > >
> > > #else
> > > #define BOOT_TARGET_DEVICE_UBIFS(func)
> > > #endif