[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: workaround install boot on btrfs with windows partition scheme
From: |
Chris Murphy |
Subject: |
Re: workaround install boot on btrfs with windows partition scheme |
Date: |
Sat, 1 Nov 2014 14:35:57 -0600 |
On Oct 30, 2014, at 2:32 AM, Michael Chang <address@hidden> wrote:
> Many shipped Windows created it's first partition aligned in 63
> (cylinder) and therefore can't offer enough room for core.img. Even
> worse the partitions has been created as logical.
>
>> sudo /sbin/fdisk -l
> Disk /dev/sda: 64.4 GB, 64424509440 bytes, 125829120 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk label type: dos
> Disk identifier: 0x0001c622
>
> Device Boot Start End Blocks Id System
> /dev/sda1 63 2056319 1028128+ b W95 FAT32
> /dev/sda2 * 2058240 125829119 61885440 f W95 Ext'd
> (LBA)
> /dev/sda5 2060288 5302271 1620992 82 Linux swap /
> Solaris
> /dev/sda6 5304320 47247359 20971520 83 Linux
> /dev/sda7 47249408 125804543 39277568 83 Linux
>
> This leaves us currently no option to succeed in installation if boot is
> on btrfs, or any other filesystems that block lists can't be used and
> core.img must be embedded in order to be reliably addressed.
>
> The attached patch try to workaround this scenario by placing the core.img
> in filesystem's (btrfs) bootloader embedding area if available to overcome
> the too small MBR gap which gets loaded by boot.img placed in MBR.
>
> Please kindly review the patch or suggests for how to fix this scenario
> sanely.
Why not have a dedicated partition with MBR type code for core.img, equivalent
to BIOSBoot currently used on GPT? freedesktop.org has a proposal to use type
code 0xEA for this purpose (in part). The boot.img code in the MBR can
arbitrarily jump to any LBA, so 0xEA doesn't need to be a primary partition
does it?
Chris Murphy
- Re: workaround install boot on btrfs with windows partition scheme,
Chris Murphy <=