Can't find correct configuration

Wed Sep 6 00:27:24 PDT 2023

I work on embedded device. The rest of the NAND is used for SPL,
U-Boot, U-Boot environment and kernel.
What is left is 248MiB.
I am not sure I can use the whole space for UBI - how will the SPL/U-Boot work?

On Wed, 6 Sept 2023 at 10:21, Zhihao Cheng <chengzhihao1 at huawei.com> wrote:
>
> 在 2023/9/6 14:57, Leon Pollak 写道:
> > Thousands of thanks, Zhihao Cheng!!!
> > It worked exactly as you wrote.
> > The only question remained is:
> > My partition size is 248MiB.
> > I thought that leaving 8MiB "spare' will be used just for these
> > reserved PEBs, but now I understand this was incorrect.
> > So, may I utilize these 8MiB back or will they still be used by UBI
> > for something?
> >
>
> I believe you have two mtd devices, 248M(mtd0 for ubi) and 8M(reserved,
> won't be accessed by UBI) now. Please don't split the 256M into two mtd
> devices if you only need 1 UBI device, just format the whole flash(256M)
> into UBI, and UBI itself will handle its reservation without user
> intervening.
>
> > On Wed, 6 Sept 2023 at 05:50, Zhihao Cheng <chengzhihao1 at huawei.com> wrote:
> >>
> >> 在 2023/9/6 10:42, Zhihao Cheng 写道:
> >>> 在 2023/9/5 22:45, Leon Pollak 写道:
> >>> Hi
> >>>> Hello, all.
> >>>> I will be very very thankful for the help to find the correct
> >>>> configuration for my NAND.
> >>>> I passed through a lot of mails in the lists and google and ChatGPT -
> >>>> no success.
> >>>> I have 256MB NAND and 248MB partition for UBIFS. I run:
> >>>> mkfs.ubifs -v -r rootfs -F -m 2048 -e 126976 -c 1981 -o ./ubifs.img
> >>>> ubinize -v -o rootfs.img -m 2048 -p 128KiB -s 512 -O 2048 ubinize.cfg
> >>>> -----
> >>>> and ubinize.cfg looks like:
> >>>> [ubifs]
> >>>> mode=ubi
> >>>> image=./ubifs.img
> >>>> vol_id=0
> >>>> vol_size=240MiB
> >>>> vol_type=dynamic
> >>>> vol_name=ubi_rootfs
> >>>> vol_alignment=1
> >>>> vol_flags=autoresize
> >>>> ------
> >>>> Kernel configuration  was with CONFIG_MTD_UBI_BEB_LIMIT=20.
> >>>> and here is the kernel log:
> >>>> [    2.695659] ubi0: attaching mtd4
> >>>> [    3.372343] ubi0: scanning is finished
> >>>> [    3.383066] ubi0 warning: ubi_eba_init: cannot reserve enough PEBs
> >>>> for bad PEB handling, reserved 4, need 40
> >>>> [    3.404320] ubi0: volume 0 ("ubi_rootfs") re-sized from 1982 to
> >>>> 1982 LEBs
> >>>> [    3.411667] ubi0: attached mtd4 (name "FS", size 248 MiB)
> >>>> [    3.417095] ubi0: PEB size: 131072 bytes (128 KiB), LEB size:
> >>>> 126976 bytes
> >>>> [    3.424006] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page
> >>>> size 512
> >>>> [    3.430740] ubi0: VID header offset: 2048 (aligned 2048), data
> >>>> offset: 4096
> >>>> [    3.437734] ubi0: good PEBs: 1990, bad PEBs: 0, corrupted PEBs: 0
> >>>> [    3.443860] ubi0: user volume: 1, internal volumes: 1, max. volumes
> >>>> count: 128
> >>>> [    3.451117] ubi0: max/mean erase counter: 1/0, WL threshold: 4096,
> >>>> image sequence number: 1590570073
> >>>> [    3.460295] ubi0: available PEBs: 0, total reserved PEBs: 1990,
> >>>> PEBs reserved for bad PEB handling: 4
> >>>> [    3.469575] ubi0: background thread "ubi_bgt0d" started, PID 131
> >>>> [    4.648718] UBIFS (ubi0:0): background thread "ubifs_bgt0_0"
> >>>> started, PID 136
> >>>> [    4.676640] UBIFS (ubi0:0): start fixing up free space
> >>>> [   10.250099] UBIFS (ubi0:0): free space fixup complete
> >>>> [   10.269046] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0,
> >>>> name "ubi_rootfs"
> >>>> [   10.276830] UBIFS (ubi0:0): LEB size: 126976 bytes (124 KiB),
> >>>> min./max. I/O unit sizes: 2048 bytes/2048 bytes
> >>>> [   10.286794] UBIFS (ubi0:0): FS size: 250142720 bytes (238 MiB, 1970
> >>>> LEBs), journal size 9023488 bytes (8 MiB, 72 LEBs)
> >>>> [   10.297540] UBIFS (ubi0:0): reserved for root: 0 bytes (0 KiB)
> >>>> [   10.303406] UBIFS (ubi0:0): media format: w4/r0 (latest is w5/r0),
> >>>> UUID A14D586A-32E2-45D7-A07E-BDC472FDF31D, small LPT model
> >>>>
> >>>> My question is: why does this warning about reserved 4, needed 40
> >>>> appear? How can I solve this?
> >>>>
> >>>
> >>> Solution: Modify ubinize.cfg,  vol_size=240MiB -> vol_size=235MiB
> >>>
> >>> Why does this warning about reserved 4, needed 40 appear?
> >>> The count of bad PEBs reserved by UBI is: total_pebs(nand chip) *
> >>> CONFIG_MTD_UBI_BEB_LIMIT/1024 = 2048 *  20 / 1024 = 40
> >>> When fastmap is not enabled, the count of internal PEBs reserved by UBI
> >>> is: UBI_LAYOUT_VOLUME_EBS[2] + WL_RESERVED_PEBS[1] +
> >>> EBA_RESERVED_PEBS[1] = 4
> >>>
> >>> Total PEBs for UBI is 1990(good PEBs: 1990), the max count of user
> >>> volume PEBs is 1990 - 40 - 4 = 1946
> >>>
> >>> In ubinize.cfg, vol_size=240MiB, the count of user volume PEBs is(see
> >>> ubinize.c in mtduitls): vi_size + (leb_size - 1) / leb_size
> >>> vi_size = 240M = 240 * 1024 * 1024
> >>> leb_size = 128K - 2K(ec) - 2K(vid) = 124 * 1024
> >>> result = 1982
> >>>
> >>> So there are 1990 - 1982 - 4 = 4 PEBs reserved for bad PEB handling,
> >>> which is less than 40.
> >>>
> >>> When we set  vol_size=235MiB, the count of user volume PEBs is: (235 *
> >>> 1024 * 1024 + 124 * 1024 - 1) / (124 * 1024) = 1941
> >>> 1990 - 4 - 40 = 1946, finally maybe there is message from kernel like
> >>> "("ubi_rootfs") re-sized from 1941 to 1946 LEBs".
> >>
> >> Acutally, the 'vol_size' in ubinize.cfg means the size of data on
> >> volume(exclude vid/ec), not the size of volume(include vid/ec).
> >>
> >
> > .
> >
>