[SOLVED]Syslinux install failed with BTRFS subvolume /boot

yhylord · 2014-07-20 04:18:51

I have a MBR 1GB device with Windows and brand new Arch on it.

After installing base and base-devel, partitioning devices, I've tried to install Syslinux.

But

# syslinux-install_update -iam
Syslinux BIOS install successful
FAILED to Set the boot flag on /dev/sda6[/bootfs]
# fdisk -l
...
/dev/sda6 *    211816845  311773454  49978305  83 Linux
...

And I couldn't see Syslinux also.
Any idea?

Last edited by yhylord (2014-07-21 06:44:39)

anatolik · 2014-07-20 04:36:21

It is weird, the boot flag is set fine.

The error message comes from https://projects.archlinux.org/svntogit … s/syslinux and it is a result of failure of 'sfdisk /dev/sda -A 6'. Could you run the command manually and post its output?

anatolik · 2014-07-20 04:37:51

You can also skip '-a' flag when run syslinux-install_update as the boot flag is already set.

FYI: I found syslinux works unstable with btrfs, that is why I moved /boot to a ext4 partition at the beginning of the disk. The rest of my machine root successfully uses btrfs.

Last edited by anatolik (2014-07-20 04:40:08)

WonderWoofy · 2014-07-20 06:06:09

The last time I tried a few months back, syslinux didn't handle /boot on a subvolume so well. This is assuming things haven't changed, but I think it uses the boot flag to find the partition to search on, then looks for /boot/syslinux and /syslinux. So if from subvolid=0, you have /bootfs/syslinux which it cannot find.

Apart from the boot flag error (which it doesn't appear as though you really need to worry about), does the machine boot okay? I ask out of curiosity more than anything else.

yhylord · 2014-07-20 06:33:20

anatolik wrote:

It is weird, the boot flag is set fine.
The error message comes from https://projects.archlinux.org/svntogit … s/syslinux and it is a result of failure of 'sfdisk /dev/sda -A 6'. Could you run the command manually and post its output?

# sfdisk /dev/sda -A 6
sfdisk: Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
sfdisk: Done
sfdisk: You have 0 active primary partitions. This does not matter for LILO,
but the DOS MBR will only boot a disk with 1 active partition.

yhylord · 2014-07-20 06:34:58

anatolik wrote:

You can also skip '-a' flag when run syslinux-install_update as the boot flag is already set.
FYI: I found syslinux works unstable with btrfs, that is why I moved /boot to a ext4 partition at the beginning of the disk. The rest of my machine root successfully uses btrfs.

# syslinux-install_update -im
Syslinux BIOS install successful
Installed MBR (/usr/lib/syslinux/bios/mbr.bin) to /dev/sda

And then when I tried to boot the computer:

Failed to load ldlinux.c32
Boot failed: please change disks and press a key to continue.

Finally I used a Windows disk to fix boot...

yhylord · 2014-07-20 06:37:43

WonderWoofy wrote:

The last time I tried a few months back, syslinux didn't handle /boot on a subvolume so well. This is assuming things haven't changed, but I think it uses the boot flag to find the partition to search on, then looks for /boot/syslinux and /syslinux. So if from subvolid=0, you have /bootfs/syslinux which it cannot find.
Apart from the boot flag error (which it doesn't appear as though you really need to worry about), does the machine boot okay? I ask out of curiosity more than anything else.

I think your opinion makes sense. I've never installed Syslinux successfully on BTRFS.
But last time it says it can support btrfs now. And I think grub sucks. It's configuration file sucks.
So I want to use Syslinux if it's possible.

WonderWoofy · 2014-07-20 13:09:35

What if you just make the subvolume /boot instead of /bootfs? This could still be mounted to /boot on the running system later (what I assume would ultimately be /rootfs/boot).

Otherwise, I am curious as to whether it would be able to recognize /syslinux if you made /bootfs the default subvolume. This would make it so that if you mounted the filesystem without any subvol= or subvolid= , it would automatically mount at /bootfs. This could of course be overridden by the use of the kernel command line and fstab as necessary.

WonderWoofy · 2014-07-20 14:13:06

It has been mentioned to me on IRC that setting the boot flag on an extended partition might not actually be enough for thing to work properly.

Ady2 on IRC wrote:

This is about how the MBR partition table selects the partition to boot to (in normal mbr.bin, "active" flag needs to be in sdx{1-4}, an "active" sdx6 is not enough). Alternative1: use primary partition. Alternative2: use altmbr.bin.

yhylord · 2014-07-21 03:51:24

WonderWoofy wrote:

What if you just make the subvolume /boot instead of /bootfs? This could still be mounted to /boot on the running system later (what I assume would ultimately be /rootfs/boot).
Otherwise, I am curious as to whether it would be able to recognize /syslinux if you made /bootfs the default subvolume. This would make it so that if you mounted the filesystem without any subvol= or subvolid= , it would automatically mount at /bootfs. This could of course be overridden by the use of the kernel command line and fstab as necessary.

The same.

yhylord · 2014-07-21 03:52:26

WonderWoofy wrote:

It has been mentioned to me on IRC that setting the boot flag on an extended partition might not actually be enough for thing to work properly.
Ady2 on IRC wrote:
This is about how the MBR partition table selects the partition to boot to (in normal mbr.bin, "active" flag needs to be in sdx{1-4}, an "active" sdx6 is not enough). Alternative1: use primary partition. Alternative2: use altmbr.bin.

Last time when I used Syslinux, I can boot on /dev/sda6.
How to use altmbr.bin?

anatolik · 2014-07-21 04:04:18

yhylord wrote:

How to use altmbr.bin?

http://www.syslinux.org/wiki/index.php/Mbr

yhylord · 2014-07-21 06:44:03

I just switch to ext4, and everything is fine now. Thank you guys.

Last edited by yhylord (2014-07-21 06:44:16)

Arch Linux

#1 2014-07-20 04:18:51

[SOLVED]Syslinux install failed with BTRFS subvolume /boot

#2 2014-07-20 04:36:21

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#3 2014-07-20 04:37:51

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#4 2014-07-20 06:06:09

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#5 2014-07-20 06:33:20

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#6 2014-07-20 06:34:58

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#7 2014-07-20 06:37:43

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#8 2014-07-20 13:09:35

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#9 2014-07-20 14:13:06

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#10 2014-07-21 03:51:24

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#11 2014-07-21 03:52:26

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#12 2014-07-21 04:04:18

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

#13 2014-07-21 06:44:03

Re: [SOLVED]Syslinux install failed with BTRFS subvolume /boot

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