Short version: sysroot is Btrfs. I made a rw snapshot of an ro snapshot in order to do a rollback, and then rebooted. The umount was clean, but during startup I noticed many services had failed, but couldn't tell why and I had no shell or remote service to get into the system. I don't know if a rw mount happened, journald is set to volatile journal so there's no log of this failed boot. I waited about 5 minutes in this state then forced a poweroff, rebooted from USB stick and btrfs check finds errors and collect information. There are many btrfs check errors in lowmem mode. It does mount ro without complaint using kernel 5.0.7.
This system has used Btrfs for years with zero corruptions until now. This system was clean installed with Fedora Rawhide ~ 2 weeks ago, with a newly created file system. Hardware: Apple Macbook Pro (2011) Samsung SSD 840 EVO 250GB, Firmware Version: EXT0DB6Q Detail version: only btrfs-progs 5.1 used mix of kernel 5.2rc2, rc3, and rc5, at the time of the snapshot and reboot with scary failures, it was using rc5+, specifically git bed3c0d84e7e mkfs.btrfs -d single -m single -n 32K /dev/sda6 mount options: noatime,ssd,space_cache=v2,compress=zstd btrfs check (normal) https://drive.google.com/open?id=1ZkIPq01lz1BxjOjxA22SUh0kSQaEeRex btrfs check lowmem https://drive.google.com/open?id=11INxc1OQbdpmqrVRlk0mNuLwmgSnnB1K btrfs super https://drive.google.com/open?id=13cNGSvjPTiYgG0smEFWecP3fk9P2Tn5G btrfs debug tree, 97MB zstd compressed https://drive.google.com/open?id=1TaxKikn9gKDjnkQpOrqWzdGYw17maCpt btrfs image, 31MB https://drive.google.com/open?id=1is_prjUhu8IBjq9oadugOi_YBYbGYGRA -- Chris Murphy
