Bug 15846

Summary:	Grub2 doesn't install the bootloader on btrfs if we have a dualboot with windows starting at sector 63
Product:	Mageia	Reporter:	Thomas Spuhler <thomas>
Component:	Installer	Assignee:	Barry Jackson <zen25000>
Status:	RESOLVED FIXED	QA Contact:
Severity:	critical
Priority:	Normal	CC:	eeeemail, thierry.vignaud, zen25000
Version:	Cauldron
Target Milestone:	---
Hardware:	All
OS:	Linux
Whiteboard:	FOR_ERRATA
Source RPM:	grub2	CVE:
Status comment:
Bug Depends on:	15374
Bug Blocks:	416
Attachments:	Image of error in installer message during boot that works Bootloader fail screen without patch

Description Thomas Spuhler 2015-05-04 20:30:38 CEST

Description of problem:
If you install mga5 on btrfs partitions  on a dualboot box with an installed windows OS, the installer cannot install the Grub2 bootloader.
If you move the start of the windows partition using a Gparted-Live and leave a 2MB (maybe 1MB suffices) empty space ahead of the windows partition then it works.
There are some postings on the WEB from OpenSuse about this problem:


https://forums.opensuse.org/showthread.php/502134-GRUB2-amp-BTRFS/page2
=> https://bugzilla.opensuse.org/show_bug.cgi?id=841247#c18
=> https://bugzilla.opensuse.org/attachment.cgi?id=611757&action=diff
I am not rating this as a release blocker, should I?

Reproducible: 

Steps to Reproduce:

Comment 1 Thierry Vignaud 2015-05-05 09:32:55 CEST

Just creating a small ext4 /boot would workaround this

CC: (none) => thierry.vignaud, zen25000
Blocks: (none) => 416

Thierry Vignaud 2015-05-10 08:49:46 CEST

Summary: Grub2 doesn't install the bootloader if we have a dualboot with windows starting at sector 63 => Grub2 doesn't install the bootloader on btrfs if we have a dualboot with windows starting at sector 63
Source RPM: (none) => grub2

Comment 2 Thierry Vignaud 2015-05-11 11:06:51 CEST

Thomas: I think we should revert your fix for bug #15374....

Keywords: (none) => PATCH
Depends on: (none) => 15374
Assignee: bugsquad => tmb

claire robinson 2015-05-11 13:05:31 CEST

CC: (none) => eeeemail

Comment 3 Samuel Verschelde 2015-05-13 15:55:55 CEST

Thierry, Thomas, is that something that must be done for mga5? (in other words, is it a release blocker)

Comment 4 Thomas Spuhler 2015-05-13 16:45:01 CEST

Samuel, Thierry:
If we don't do anything, we will have a lot of folks with a problem and we could be trashed by a reviewer. On the other hand, if we introduce a fix this late w/o a lot of testing by cauldron users, we could have a problem too. I would favor a prominent paragraph in the Release Notes and Errata.
I moved the start of the windows using GParted-live. It's very easy. Unfortunately, we don't provide it on our Live-DVD (there is probably no room on the Live-CD)

Samuel Verschelde 2015-05-31 21:38:34 CEST

Whiteboard: (none) => FOR_ERRATA

Comment 5 Thierry Vignaud 2016-06-06 11:48:51 CEST

Barry can you fix grub2 regarding booting from btrfs?

Keywords: PATCH => (none)
Assignee: tmb => zen25000

Comment 6 Barry Jackson 2016-06-06 12:53:10 CEST

If anyone can test this, a test grub2 build with the OpenSuSE patch from #0 is here in my repo now: grub2-2.02-0.git10457.6.2

Install by adding and enabling http://mtf.no-ip.co.uk/pub/linux/barjac/distrib/cauldron/x86_64/media/extra/release/

s/x86_64/i586/ for the i586 build.

Remove that media afterwards as there is all-sorts of test stuff in there you REALLY do not want!

Comment 7 Barry Jackson 2016-06-06 18:06:32 CEST

I happened to have a VM with Windows-8.1 (UEFI) and tried a net-install of Mga6 cauldron onto btrfs next to it.

I now know that the Windows recovery partition is sda1 and
first sector: 2048 (at 1024.0 KiB)

However, grub2 install failed.
(fail message in attachment to follow)

I closed the VM and ran the installer again with the patched grub2 in #6 available and the install completed.
Other than a cryptic message in the grub2 console at boot there were no problems and it booted into LXDE.

So it seems that the patch does something useful for btrfs even when the first sector start is not at sector 63.

Comment 8 Barry Jackson 2016-06-06 18:10:26 CEST

Created attachment 7935 [details]
Image of error in installer

Comment 9 Barry Jackson 2016-06-06 18:15:38 CEST

Created attachment 7936 [details]
message during boot that works

This message displays for a few seconds before booting completes normally.

Comment 10 Barry Jackson 2016-06-07 12:44:55 CEST

OK - success!

I installed XP in a VM which did place itself at sector 63.

I then net-installed Cauldron alongside it on btrfs root using free space above XP.

Using current Cauldron grub2 it failed installing bootloader with the error which I will attach below.

I shut down the VM and re-ran the net install to upgrade my previous install, but added my local repo with the patched grub2.

The bootloader install went without error and on re-boot the boot was successful. (Not to graphical, but that is another issue probably with VBox) 

@Thierry
Are you OK for me to push this now, or would you prefer it went to updates_testing first?

Comment 11 Barry Jackson 2016-06-07 12:47:02 CEST

Created attachment 7937 [details]
Bootloader fail screen without patch

Bootloader failure before updating to patched grub2 in installer.

Comment 12 Barry Jackson 2016-06-07 13:10:43 CEST

I saw no regression in my current ext4 system with this patched version.

It is now in svn.

Comment 13 Barry Jackson 2016-06-07 18:44:08 CEST

OK pushed to Cauldron.

Closing as fixed.

Status: NEW => RESOLVED
Resolution: (none) => FIXED