On Sun, Mar 28, 2021 at 9:41 AM B A <chris....@web.de> wrote: > > Dear btrfs experts, > > > On my desktop PC, I have 1 btrfs partition on a single SSD device with 3 > subvolumes (/, /home, /var). Whenever I boot my PC, after logging in to > GNOME, the btrfs partition is being remounted as ro due to errors. This is > the dmesg output at that time: > > > [ 616.155392] BTRFS error (device dm-0): parent transid verify failed on > > 1144783093760 wanted 2734307 found 2734305 > > [ 616.155650] BTRFS error (device dm-0): parent transid verify failed on > > 1144783093760 wanted 2734307 found 2734305 > > [ 616.155657] BTRFS: error (device dm-0) in __btrfs_free_extent:3054: > > errno=-5 IO failure > > [ 616.155662] BTRFS info (device dm-0): forced readonly > > [ 616.155665] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2124: > > errno=-5 IO failure
transid error usually means something below Btrfs got the write ordering wrong and one or more writes dropped, but the problem isn't detected until later which means it's an older problem. What's the oldest kernel this file system has been written with? That is, is it a new Fedora 33 file system? Or older? Fedora 33 came with 5.8.15. ERROR: child eb corrupted: parent bytenr=1144783093760 item=14 parent level=1 child level=2 ERROR: child eb corrupted: parent bytenr=1144881201152 item=14 parent level=1 child level=2 Can you post the output from both: btrfs insp dump-t -b 1144783093760 /dev/dm-0 btrfs insp dump-t -b 1144881201152 /dev/dm-0 > What shall I do now? Do I need any of the invasive methods (`btrfs rescue` or > `btrfs check --repair`) and if yes, which method do I choose? No repairs yet until we know what's wrong and if it's safe to try to repair it. In the meantime I highly recommend refreshing backups of /home in case this can't be repaired. It might be easier to do this with a Live USB boot of Fedora 33, and use 'mount -o ro,subvol=home /dev/dm-0 /mnt/home' to mount your home read-only to get a backup. Live environment will be more cooperative. -- Chris Murphy
