Re: system stuck with flush-btrfs-4 at 100% after filesystem resize

[John Navitsky <john@navitsky.org>]

As a follow-up, at some point over the weekend things did finish on 
their own:

romulus:/vms/johnn-sles11sp3 # df -h /vms
Filesystem      Size  Used Avail Use% Mounted on
/dev/dm-4       2.6T  1.6T  1.1T  60% /vms
romulus:/vms/johnn-sles11sp3 #

I'd still be interested in any comments about what was going on or 
suggestions.

Thanks,

-john

On 2/8/2014 10:36 AM, John Navitsky wrote:
> Hello,
>
> I have a large file system that has been growing.  We've resized it a
> couple of times with the following approach:
>
>    lvextend -L +800G /dev/raid/virtual_machines
>    btrfs filesystem resize +800G /vms
>
> I think the FS started out at 200G, we increased it by 200GB a time or
> two, then by 800GB and everything worked fine.
>
> The filesystem hosts a number of virtual machines so the file system is
> in use, although the VMs individually tend not to be overly active.
>
> VMs tend to be in subvolumes, and some of those subvolumes have snapshots.
>
> This time, I increased it by another 800GB, and it it has hung for many
> hours (over night) with flush-btrfs-4 near 100% cpu all that time.
>
> I'm not clear at this point that it will finish or where to go from here.
>
> Any pointers would be much appreciated.
>
> Thanks,
>
> -john (newbie to BTRFS)