currupted btrfs breaks both recovery and boot

[god]

If btrfs volume is corrupted (separate /home partition, not even / !!!) than not only booting ubuntu in normal AND recovery mode is impossible but even liveusb fails as well. The recovery drops to shell but it's impossible to fix btrfs - there's unkillable mount -t btrfs... process hanging and kernel regularly pukes with "btrfs-transacti blocked for 120 seconds" message.

This is beyond horrible - the whole purpose of recovery mode is to fix errors like that, errors on partition which is not used to boot from (e. g. /home) should never ever break it. Alternatively you could add new mode to grub menu - smth like "recovery which actually works" or something like that.

The workaround is to add 'break=premount' to grub command line and fix btrfs with 'btrfs check --repair /dev/dm-....' from initramfs.

Found on xubuntu 15.04 x86_64.

[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 1452165

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.

[god (humper)]

What kind of logfiles do you require?
Just install separate /home on btrfs, start watching some porn in browser or some other activity activity writing to files in there and force shutdown your desktop by long-press of power button. Do this several times until the fs is corrupted (you'll notice it due to stuck boot) and try to use recovery mode and liveusb.

[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/

[god (humper)]

I appreciate your help but I'm rather reluctant to corrupt my fs for the sake of testing another kernel version.

[god (humper)]

If you know a way to reliably get btrfs corupted than you can test it yourself on dedicated VM.

[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 1452165

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.