Someone on IRC suggested that I clear the free cache: > sudo mount -o remount,clear_cache /path/to/dev /path/to/mount > sudo mount -o remount,space_cache /path/to/dev /path/to/mount
The former command printed `btrfs: disk space caching is enabled` and the latter repeated it, making me think that maybe the latter was unnecessary. On 29 July 2014 09:04, Peter Waller <pe...@scraperwiki.com> wrote: > Hi All, > > I've reported a bug with Ubuntu here: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1349711 > > The machine in question 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. > > We have other machines in a similar configuration which have not > displayed this behaviour. > > The one thing which makes this machine different is that it has > directories which contain many thousands of files. We don't make heavy > use of subvolumes or snapshots. > > More details follow: > > # cat /proc/version_signature > Ubuntu 3.13.0-32.57-generic 3.13.11.4 > > The machine had a soft-lockup with messages like this appearing on the > console: > > [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] > > > After the first lockup and reboot, the following messages were in > dmesg, which I ignored because after some research I saw that they > were changed to warnings and considered non-harmful. A btrfs-scrub > performed after this failed without error: > > > [ 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 > > > After the second time I've observed the lockup and rebooted, these > messages have appeared: > > > [ 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 > > > I would like to know if these second messages are harmful and if > remedial action is needed in response to the latter messages. > Searching for messages similar to my lockup I found this report which > suggested the problem may be fixed in 3.14. > > Any advice appreciated, > > Thanks, > > - Peter -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
