On Thu, Nov 30, 2023 at 10:25:48PM -0500, Kent Overstreet wrote: > On Thu, Nov 30, 2023 at 08:47:33PM -0500, Daniel J Blueman wrote: > > Hi Kent et al, > > > > On upstream bcachefs (master @ evilpiepirate.org/git/bcachefs.git) SHA > > f8a1ba26, I was able to develop a minimal reproducer [1] for a page > > not present oops I can provoke [2]. It appears we need further > > synchronisation during unmount. > > > > Let me know when there is a patch I can test, or for debug. > > > > Thanks, > > Dan > > > > -- [1] > > > > modprobe brd rd_size=536870912 rd_nr=2 > > bcachefs format -f /dev/ram0 /dev/ram1 > > mount -t bcachefs /dev/ram0:/dev/ram1 /mnt > > fio --group_reporting --ioengine=io_uring --directory=/mnt --size=16m > > --time_based --runtime=60s --iodepth=256 --verify_async=8 --bs=4k-64k > > --norandommap --random_distribution=zipf:0.5 --numjobs=16 --rw=randrw > > --name=A --direct=1 --name=B --direct=0 >/dev/null & > > bcachefs device evacuate /dev/ram0 > > bcachefs device remove --force --force-metadata /dev/ram1 > > bcachefs device remove --force --force-metadata /dev/ram1 > > kill %1 > > wait > > umount /mnt > > The remove fails for me with DEVICE_SET_STATE_NOT_ALLOWED - evacuate set > ram0 to ro, we can't remove our last rw dev.
Got it to repro, just had to ignore those errors - there's now a ktest test for it, and the fix is in master :)
