http://bugzilla.opensuse.org/show_bug.cgi?id=1136436

Bug ID: 1136436 Summary: btrfs mainainance crashed and left system unbootable Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: P.Suetterlin@royac.iac.es QA Contact: qa-bugs@suse.de Found By: --- Blocker: ---

Last night my Tumbleweed system (20190520) performed the regular btrfs maintainance. I was working at that time, and noticed that the application I used did not respond anymore. Other stuff seemed to continue working (e.g., bringing an editor window in front). So I thought its the application and tried to terminate it, but nothing happened. Short after that everything on the screen became unresponsive, keyboard LEDS didn't react on state change etc.

I finally pressed the power button to restart the system (laptop, no reset).

However, the boot did not succeed. It hang, systemd reporting its waiting for four processes. Two of those were 'flush journal to persistent memory' and 'save rfkill switch state'. For some time the console display showed those jobs in a loop, then it would also stop and become unresponsive. This was consistent, I tried some three times or so.

So I finally booted from an USB rescue stick. I could mount the FS without problems. Not knowing better, I ran a 'btrfs scrub' on it, which finished after some 1-2 minutes without errors. Not sure what to do next, I rebooted from the hard disk - and the system came up clean.

By now I assume the crashes/hangs were only temporary(?) and the system might have returned after longer waits, but I'm not absolutely sure.

However, looking at the logfile from the first hang I found some issue where balancing failed with a 'no space left on device (although it has/had 5.6G free when starting). More alarming was this one:

May 27 00:02:10 woodstock.pitnet btrfs-balance.sh[17806]: Done, had to relocate 1 out of 84 chunks May 27 00:02:10 woodstock.pitnet kernel: BTRFS info (device sda2): balance: start -musage=10 -susage=10 May 27 00:02:10 woodstock.pitnet kernel: BTRFS info (device sda2): relocating block group 398848950272 flags system May 27 00:02:10 woodstock.pitnet kernel: BTRFS info (device sda2): relocating block group 398815395840 flags metadata May 27 00:02:10 woodstock.pitnet kernel: assertion failed: root, file: fs/btrfs/relocation.c, line: 804 May 27 00:02:10 woodstock.pitnet kernel: ------------[ cut here ]------------ May 27 00:02:10 woodstock.pitnet kernel: kernel BUG at fs/btrfs/ctree.h:3518!

Unfortunately the log ends with this line, so no more info.

The full system log starting with the btrfs maintainance call is available at http://paste.opensuse.org/24906643 (1 month lifetime - should I rather attach it?)