-8 kernel sometimes makes grub-probe unable to detect btrfs

[Martin Erik Werner]

Running the 2.6.38-8.41 kernel, update-grub no longer adds the rootflags=subvol=@ option for btrfs.
Booting back into -7 and running update-grub correctly adds the option to all kernels.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image-2.6.38-8-generic 2.6.38-8.41
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: I82801AAICH [Intel 82801AA-ICH], device 0: Intel ICH [Intel 82801AA-ICH]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: arand 1305 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'I82801AAICH'/'Intel 82801AA-ICH with STAC9700,83,84 at irq 11'
   Mixer name : 'SigmaTel STAC9700,83,84'
   Components : 'AC97a:83847600'
   Controls : 34
   Simple ctrls : 24
CurrentDmesg:
 [ 20.404989] ISO 9660 Extensions: RRIP_1991A
 [ 22.190168] eth0: no IPv6 routers present
Date: Wed Apr 6 13:44:17 2011
IwConfig:
 lo no wireless extensions.

 eth0 no wireless extensions.
Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: Bochs Bochs
ProcEnviron:
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-2.6.38-8-generic root=UUID=54e7f946-69a5-4cf7-891c-c7fad695ea4e ro rootflags=subvol=@ console=tty0 console=ttyS0,115200n8
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic N/A
 linux-backports-modules-2.6.38-8-generic N/A
 linux-firmware 1.49
RfKill:

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/01/2007
dmi.bios.vendor: Bochs
dmi.bios.version: Bochs
dmi.chassis.type: 1
dmi.chassis.vendor: Bochs
dmi.modalias: dmi:bvnBochs:bvrBochs:bd01/01/2007:svnBochs:pnBochs:pvr:cvnBochs:ct1:cvr:
dmi.product.name: Bochs
dmi.sys.vendor: Bochs

[Martin Erik Werner (arand)]

It currently seems like this issue has magically disappeared, there was an upgrade, however I see no packages which would be related to this.

[Martin Erik Werner (arand)]

...And back again.
Seems to have popped up again when I reinstalled linux-image-###, and disappeared again when I reinstalled linux-headers-###.

However I can't actually reproduce this... *sigh*

[Martin Erik Werner (arand)]

It seems like somehow the trigger for this is the act of snapshotting... In combination with reinstalling kernel packages?

I've bee using apt-btrfs-snapshot, hence why it was (though still is) really tricky to pin down..

[Martin Erik Werner (arand)]

Aha!
It seems like sometimes, for some reason, reinstalling the kernel packages renders grub-probe unable to detect the type of the filesystem for /, hence why it doesn't writ the btrfs-related bootflag...

[Martin Erik Werner (arand)]

...And for some reason, making a snapshot of the / subvolume is somethimes a way to "unstuck" this behaviour.

It is fae from consistent though, which is rather bothersome.