Created attachment 182251 [details] virsh console output Happens with 4.2rc1 as well. btrfs-progs 4.1 1. New ext4 file system populated with Fedora 22 installation, and a ~1.5GB ISO file. 2. btrfs-convert /dev/vdb1 succeeds no errors, btrfs check has no complaints either 3. mount /dev/vdb1 /mnt 4. btrfs scrub /mnt scrub started on /mnt, fsid 7830af7c-601b-406e-8362-85e907c27c5d (pid=1164) ...complete kernel implosion, it's a really bad panic, ssh dies, the console dies, so fortunately virsh console can help capture it!
Starting over again at step 1. above: [root@localhost ~]# mount /dev/vdb1 /mnt [root@localhost ~]# ll total 1397764 -rw-r--r--. 1 root root 1431306240 Jul 7 22:27 Fedora-Live-Workstation-x86_64-22-3.iso [root@localhost ~]# rm *iso rm: remove regular file ‘Fedora-Live-Workstation-x86_64-22-3.iso’? y [root@localhost ~]# umount /mnt [root@localhost ~]# btrfs-convert /dev/vdb1 create btrfs filesystem: blocksize: 4096 nodesize: 16384 features: extref, skinny-metadata (default) creating btrfs metadata. copy inodes [o] [ 155343/ 155714] creating ext2fs image file. cleaning up system chunk. conversion complete. [root@localhost ~]# mount /dev/vdb1 /mnt [root@localhost ~]# btrfs sub list /mnt ID 256 gen 16 top level 5 path ext2_saved [root@localhost ~]# btrfs sub del /mnt/ext2_saved/ Delete subvolume (no-commit): '/mnt/ext2_saved' [root@localhost ~]# btrfs fi defrag -r /mnt [root@localhost ~]# umount /mnt [root@localhost ~]# btrfs check /dev/vdb1 Checking filesystem on /dev/vdb1 UUID: 2c64337a-7ac9-45cf-a396-8af0c770066d checking extents checking free space cache checking fs roots checking csums checking root refs found 5914157064 bytes used err is 0 total csum bytes: 5117496 total tree bytes: 673841152 total fs tree bytes: 660176896 total extent tree bytes: 6504448 btree space waste bytes: 184429909 file data blocks allocated: 5245952000 referenced 5245952000 btrfs-progs v4.1 [root@localhost ~]# mount /dev/vdb1 /mnt [root@localhost ~]# btrfs scrub start /mnt scrub started on /mnt, fsid 2c64337a-7ac9-45cf-a396-8af0c770066d (pid=1322) [root@localhost ~]# ..hang.. NOTHING in vmm console or journalctl -f and ssh is dead, and the vmm console is dead reboot with console=tty0, etc and virsh console attached... [root@localhost ~]# mount /dev/vdb1 /mnt [root@localhost ~]# btrfs scrub status /mnt scrub status for 2c64337a-7ac9-45cf-a396-8af0c770066d no stats available total bytes scrubbed: 0.00B with 0 errors [root@localhost ~]# btrfs scrub start /mnt again total instant hang, vmm console shows nothing, but the virsh console captures probably the same thing as the earlier attachment. But the point is that it's not the huge ISO that's causing this. There are no other 1+GB files on this otherwise fresh ext4 file system with Fedora 22 installed (it doesn't install anything even close to that size).
Created attachment 182261 [details] virsh console output c1 This is the output from virsh console captured for the scrub at the end of comment 1, where the big ISO file had been delete prior to the conversion.