On 2019/8/1 下午4:07, Swâmi Petaramesh wrote: > On 8/1/19 8:36 AM, Qu Wenruo wrote: >> Could you give more detailed history, including each reboot? >> Like: >> >> CASE 1 >> # Upgrade kernel (running 5.1) >> # Reboot >> # Kernel mount failure (running 5.2) > > No, it never was a “kernel mount failure”, it was more of : > > - Running 5.1 OK > > - Upgrade to 5.2 > > - Reboot without noticing problem on kernel 5.2.1-arch1-1 > > - Performed usual remote rsync backup using kernel 5.2.1-arch1-1 WITHOUT > any error at 23:20 on july, 16 > > - Quite unfortunately I do not backup /var/log in frequent rsync backups... > > - Machine does its usual cronned snapper snapshots auto-delete > > - Turned off machine for the night So it looks like damage is done at this point. It looks like some data doesn't reach disk properly. > > - Next days, boot machine as usual (without paying attention to > scrolling messages) > > - Machine boots. Cinnamon GUI fails loading. Wonders. Reboot. > > - Notice BTRFS error messages on console at boot. Still no GUI. > > - Reboot in systemd rescue mode. Run "btrfs check -f" in read-only mode. > > - Get LOADS of error messages. > > - Tells myself « Jeez the damn thing screwed up ! » > > - Reboot in multi-user.target console mode > > - Notice BTRFS errors again. > > - Connect external USB HD for performing an emergency full backup of > what can be. > > - Lack enough space on external USB HD. Delete a load of old snapshots > to make enough space. Indeed looks like some btrfs bug in 5.2 now. So far, the common workload involves snapshot deletion and proper shutdown. I need to double check the snapshot deletion with dm-logwrites. Thanks for the detailed history, this helps more than the btrfs check/log message. Thanks, Qu
