btrfs blocks root filesystem mount on 15.04

[Ante Karamatić]

Powered on my laptop (XPS 13) and it newer booted up. Attaching screenshots showing btrfs blocking mounting.

Kernel 3.19.0-15-generic

[Ante Karamatić (ivoks)]

Tried older 3.16.0, same result. 3.13 booted fine. Next reboot, after 3.13, 3.19 also booted fine.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1454796

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Ante Karamatić (ivoks)]

Well, filesystem was not mounted, I could not collect logs, which haven't been written.

[Joseph Salisbury (jsalisbury)]

Can you not reproduce the bug after you once booted into 3.13?

[Ante Karamatić (ivoks)]

This is actually a second time it happened. First time it was with 3.16.0 a month ago. Multiple reboots, power off/on, nothing helped. At that time I didn't collect any additional data. Now, second time it happened, symptoms were exactly the same - and way to fix it was exactly the same. I usually do not power off my laptop, rather suspend it. But I'll power it off more often now in order to reproduce it again.

[Ante Karamatić (ivoks)]

I can easily reproduce the problem if I do unclean shutdown. After that, it doesn't boot. 3.13.0 boots without issues.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.1 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.1-rc3-vivid/

[Ante Karamatić (ivoks)]

I've tested it with '4.1.0-040100rc3-generic #201505102036'. I've forced shutdown 4 times and each time it booted up fine with this kernel. Then, 5th time I tried booting 3.19.0 and it failed. I rebooted with '4.1.0-040100rc3-generic #201505102036' and it booted just fine. So, it looks like this kernel does fixes this problem.

[Ante Karamatić (ivoks)]

Did few more reboots, and I can confirm that it does solve the problem. Reproduced the problem multiple times with 3.19, while I couldn't with 4.1.

[Joseph Salisbury (jsalisbury)]

That's good news, so this is fixed upstream. We can perform a "Reverse" bisect to identify the exact commit that fixes this.

First, can you test the latest upstream 3.19 kernel to see if the fix in mainline was already sent to stable? It can be downloaded from:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19.8-vivid/

[Ante Karamatić (ivoks)]

I can't reproduce it with 3.19.8.

[Joseph Salisbury (jsalisbury)]

That is great news. The Ubuntu 3.19.0-18 kernel has the upstream 3.19.8 upstream stable updates, so Vivid will have this fix when 3.19.0-18 is released.

I build a 3.19.0-18 Vivid kernel with what is currently in the master-next branch. Can you see if this kernel also fixes the bug? It can be downloaded from:

http://kernel.ubuntu.com/~jsalisbury/lp1454796/

Note, you need to install both the linux-image and linux-image-extra .deb packages.

[Ante Karamatić (ivoks)]

3.19.0-18 also works. It boots when 3.19.0-16 doesn't.

[Andy Whitcroft (apw)]

This bug was nominated against a series that is no longer supported, ie vivid. The bug task representing the vivid nomination is being closed as Won't Fix.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.