Repost of what I sent to the mailing list just now: My current interpretation of this problem is that it is some pathological condition caused by not rebalancing and being nearly out of space for allocating more metadata and hence it is rarely being seen by anyone else (because most users are regularly doing rebalances).
See this thread for details about rebalancing and out of space: "ENOSPC with mkdir and rename" on 2014-08-02: http://thread.gmane.org/gmane.comp.file-systems.btrfs/37415 I haven't had the lockups in production since July and I'm now trialling a nightly rebalance: $ btrfs filesystem balance start -dusage=50 -musage=10 "$mount" I'll report back if I encounter further problems. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1349711 Title: Machine lockup in btrfs-transaction Status in “linux” package in Ubuntu: Confirmed Bug description: This has happened twice now. I'm on an AWS EC2 m3.large instance with the official Ubuntu AMI ami- 776d9700. # cat /proc/version_signature Ubuntu 3.13.0-32.57-generic 3.13.11.4 After running for many days, the machine locked up with the below messages appearing on the console. The machine would respond to ping but not SSH or HTTP requests. The machine has one BTRFS volume which is 87% full and lives on an Logical Volume Manager (LVM) block device on top of one Amazon Elastic Block Store (EBS) device. Error messages after first reboot: [ 77.609490] BTRFS error (device dm-0): block group 10766778368 has wrong amount of free space [ 77.613678] BTRFS error (device dm-0): failed to load free space cache for block group 10766778368 [ 77.643801] BTRFS error (device dm-0): block group 19356712960 has wrong amount of free space [ 77.648952] BTRFS error (device dm-0): failed to load free space cache for block group 19356712960 [ 77.926325] BTRFS error (device dm-0): block group 20430454784 has wrong amount of free space [ 77.931078] BTRFS error (device dm-0): failed to load free space cache for block group 20430454784 [ 78.111437] BTRFS error (device dm-0): block group 21504196608 has wrong amount of free space [ 78.116165] BTRFS error (device dm-0): failed to load free space cache for block group 21504196608 Error messages after second reboot: [ 45.390221] BTRFS error (device dm-0): free space inode generation (0) did not match free space cache generation (70012) [ 45.413472] BTRFS error (device dm-0): free space inode generation (0) did not match free space cache generation (70012) [ 467.423961] BTRFS error (device dm-0): block group 518646661120 has wrong amount of free space [ 467.429251] BTRFS error (device dm-0): failed to load free space cache for block group 518646661120 Error messages on the console after second lock-up follow: [246736.752053] INFO: rcu_sched self-detected stall on CPU { 0} (t=2220246 jiffies g=35399662 c=35399661 q=0) [246736.756059] INFO: rcu_sched detected stalls on CPUs/tasks: { 0} (detected by 1, t=2220247 jiffies, g=35399662, c=35399661, q=0) [246764.192014] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u30:2:1828] [246764.212058] BUG: soft lockup - CPU#1 stuck for 23s! [btrfs-transacti:492] [246792.192022] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u30:2:1828] [246792.212057] BUG: soft lockup - CPU#1 stuck for 23s! [btrfs-transacti:492] [246820.192052] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u30:2:1828] [246820.212018] BUG: soft lockup - CPU#1 stuck for 23s! [btrfs-transacti:492] [246848.192052] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u30:2:1828] [246848.212058] BUG: soft lockup - CPU#1 stuck for 23s! [btrfs-transacti:492] [246876.192053] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [246876.212057] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [246904.192053] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [246904.212058] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [246916.772052] INFO: rcu_sched self-detected stall on CPU[246916.776058] INFO: rcu_sched detected stalls on CPUs/tasks: [246944.192053] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [246944.212058] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [246972.192053] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [246972.212018] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [247000.192053] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [247000.212058] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [247028.192054] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u30:2:1828] [247028.212058] BUG: soft lockup - CPU#1 stuck for 22s! [btrfs-transacti:492] [247056.192053] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u30:2:1828] [247056.212061] BUG: soft lockup - CPU#1 stuck for 23s! [btrfs-transacti:492] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1349711/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
