Unfortunately that doesn't appear to be it, a forced restart and attempted to mount with skip_balance leads to the same thing. 20 minutes in btrfs-transactio had a large burst of reads then started spinning the CPU with the disk idle. Is this recoverable? I could leave it for a day or so if it may make progress, but if not I'd like to start on other options. On Fri, Aug 10, 2018 at 3:59 AM, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: > > > On 8/10/18 3:40 PM, Dan Merillat wrote: >> Kernel 4.17.9, 11tb BTRFS device (md-backed, not btrfs raid) >> >> I was testing something out and enabled quota groups and started getting >> 2-5 minute long pauses where a btrfs-transaction thread spun at 100%. > > Looks pretty like a running balance and quota. > > Would you please try with balance disabled (temporarily) with > skip_balance mount option to see if it works. > > If it works, then either try resume balance, or just cancel the balance. > > Nowadays balance is not needed routinely, especially when you still have > unallocated space and enabled quota. > > Thanks, > Qu > >> >> Post-reboot the mount process spinds at 100% CPU, occasinally yielding >> to a btrfs-transaction thread at 100% CPU. The switchover is marked >> by a burst of disk activity in btrace. >> >> Btrace shows all disk activity is returning promptly - no hanging submits. >> >> Currently the mount is at 6+ hours. >> >> Suggestions on how to go about debugging this? >> >
