Hi, After a few weeks of testing and preparation I commissioned a new NFS server with btrfs for the main storage. I ran into two situations where the btrfs locked up and I had to hard reboot the machine (sysrq-b). I end up with btrfs-transac in state D, waiting for the pending transaction to be completed if I interpret the code right. On top of that all eight nfsds are in state D waiting to start several different transactions. I have attached the sysrq-t output after I killed all processes I could before rebooting.
It only seems to happen with somewhat heavier IO load, in this case one process md5summing large files (a few TB in total) while another process tries to write to the NFS share. I never saw it e.g. while copying single files onto the file system or reading multiple files. I'll be glad for any hints and recommendations. Christian
dmesg.bz2
Description: BZip2 compressed data
