On Mon, Oct 13, 2014 at 11:12 AM, Rich Freeman <r-btrfs@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Oct 9, 2014 at 10:19 AM, Petr Janecek <janecek@xxxxxx> wrote: >> >> I have trouble finishing btrfs balance on five disk raid10 fs. >> I added a disk to 4x3TB raid10 fs and run "btrfs balance start >> /mnt/b3", which segfaulted after few hours, probably because of the BUG >> below. "btrfs check" does not find any errors, both before the balance >> and after reboot (the fs becomes un-umountable). >> >> [22744.238559] WARNING: CPU: 0 PID: 4211 at fs/btrfs/extent-tree.c:876 btrfs_lookup_extent_info+0x292/0x30a [btrfs]() >> >> [22744.532378] kernel BUG at fs/btrfs/extent-tree.c:7727! > > I am running into something similar. I just added a 3TB drive to my > raid1 btrfs and started a balance. The balance segfaulted, and I find > this in dmesg: I got another one of these crashes during a balance today, and this is on 3.17.1 with the "Btrfs: race free update of commit root for ro snapshots" patch. So, there is something else in 3.17.1 that causes this problem. I did see mention of an extent error of some kind on the lists and I don't have that patch - I believe it is planned for 3.17.2. After the crash the filesystem became read-only. I didn't have any way to easily capture the logs, but I got repeated crashes when trying to re-mount the filesystem after rebooting. The dmesg log showed read errors from one of the devices (bdev /dev/sdb2 errs: wr 0, rd 1361, flush 0, corrupt 0, gen 0). When I tried to btrfs check the filesystem with btrfs-progs 3.17 it abruptly terminated and output an error mentioning could not find extent items followed by root and a really large number. I finally managed to recover by mounting the device with skip_balance - I suspect that it was crashing due to attempts to restart the failing balance. Then after letting the filesystem settle down I unmounted it cleanly and rebooted and everything was back to normal. However, i'm still getting "bdev /dev/sdb2 errs: wr 0, rd 1361, flush 0, corrupt 0, gen 0" in my dmesg logs. I have tried scrubbing the device with no errors found. -- Rich -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
