On 28 Nov 2018, at 11:05, Andrea Gelmini wrote: > On Tue, Nov 27, 2018 at 10:16:52PM +0800, Qu Wenruo wrote: >> >> But it's less a concerning problem since it doesn't reach latest RC, >> so >> if you could reproduce it stably, I'd recommend to do a bisect. > > No problem to bisect, usually. > But right now it's not possible for me, I explain further. > Anyway, here the rest of the story. > > So, in the end I: > a) booted with 4.20.0-rc4 > b) updated backup > c) did the btrfs check --read-only > d) seven steps, everything is perfect > e) no complains on screen or in logs (never had) > f) so, started to compile linux-next 20181128 (on another partition) > e) without using (reading or writing) on /home, I started > f) btrfs filesystem defrag -v -r -t 128M /home > g) it worked without complain (in screen or logs) > h) then, reboot with kernel tag 20181128 > i) and no way to mount:
I think (hope) this is: https://bugzilla.kernel.org/show_bug.cgi?id=201685 Which was just nailed down to a blkmq bug. It triggers when you have scsi devices using elevator=none over blkmq. -chris
