BTRS Raid boot failure

[Peter Würtz]

After upgrading from Ubuntu 18.10 to 19.04 my BTRFS Raid0 based system doesn't boot anymore.

It drops to busybox because of an error mounting the root file system.

Manually trying to mount root reveals an error message saying that the second raid volume could not be found by UUID. But the output from `blkid` shows that the volume with the UUID in question exists.

Booting the system using the previous kernel 4.18 from advanced boot options works flawlessly.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: linux-image-generic 5.0.0.15.16
ProcVersionSignature: Ubuntu 4.18.0-20.21-generic 4.18.20
Uname: Linux 4.18.0-20-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: pwuertz 1702 F.... pulseaudio
Date: Thu May 30 09:03:47 2019
HibernationDevice: RESUME=UUID=d477a5f5-0176-4b8a-937a-b97db8fef8d4
InstallationDate: Installed on 2016-04-28 (1126 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Sony Corporation VPCZ21C5E
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.18.0-20-generic root=UUID=aa8fbe5e-c722-43e9-b8fc-9d7f60818a46 ro rootflags=subvol=@ quiet splash
PulseList:
 Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
 No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-4.18.0-20-generic N/A
 linux-backports-modules-4.18.0-20-generic N/A
 linux-firmware 1.178.1
SourcePackage: linux
UpgradeStatus: Upgraded to disco on 2019-05-30 (0 days ago)
dmi.bios.date: 06/16/2011
dmi.bios.vendor: INSYDE
dmi.bios.version: R0170H5
dmi.board.asset.tag: N/A
dmi.board.name: VAIO
dmi.board.vendor: Sony Corporation
dmi.board.version: N/A
dmi.chassis.asset.tag: N/A
dmi.chassis.type: 10
dmi.chassis.vendor: Sony Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnINSYDE:bvrR0170H5:bd06/16/2011:svnSonyCorporation:pnVPCZ21C5E:pvrJ004QCLG:rvnSonyCorporation:rnVAIO:rvrN/A:cvnSonyCorporation:ct10:cvrN/A:
dmi.product.family: VAIO
dmi.product.name: VPCZ21C5E
dmi.product.sku: N/A
dmi.product.version: J004QCLG
dmi.sys.vendor: Sony Corporation

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Kai-Heng Feng (kaihengfeng)]

Please test latest mainline kernel:
[1] https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.2-rc2/

[Peter Würtz (pwuertz)]

I managed to mount the root volume from the kernel 5 boot fail busybox by explicitly adding the correct device=/dev/sdXY names to the btrfs mount options. After this one time manual mount, kernel 5 seems to boot fine now. Seems like the kernel 5 btrfs driver "fixed" whatever it had trouble with.

Can't verify if kernel 5.2 would have fixed the problem automatically though..