On Wed, May 8, 2019 at 11:55 PM Trent Lloyd <trent.ll...@canonical.com> wrote:
> I have been running into this (curtin 18.1-17-gae48e86f- > 0ubuntu1~16.04.1) > > I think this commit basically agrees with my thoughts but I just wanted > to share them explicitly in case they are interesting > > (1) If you *unregister* the cache device from the backing device, it > first has to purge all the dirty data back to the backing device. This > may obviously take a while. > > (2) When doing that, I managed to deadlock bcache at least once on > xenial-hwe 4.15 where it was trying to reclaim memory from XFS, which I > assume was trying to write to the bcache.. traceback: > https://pastebin.canonical.com/117528/ - you can't get out of that > without a reboot > Thanks for capturing those; Ive quite a few of my own as an unregister path which _should_ work; but doesn't for various bugs in bcache. I need to attach those OOPS to this bug as well. > > (3) However generally I had good luck simplying "stop"ing the cache > devices (it seems perhaps that is what this bug is designed to do, > switch to stop, instead of unregister?). Specifically though I was > stopping the backing devices, and then later the cache device. It seems > like the current commit is the other way around? > Unregister is just not stable, so stopping is what is being done now. I did attempt stopping bcache devices first and only once all bcache devices were stopped to then stop and remove a cacheset; this proved unreliable under our integration testing of various bcache scenarios. > > ** Tags added: sts > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/1796292 > > Title: > Tight timeout for bcache removal causes spurious failures > > To manage notifications about this bug go to: > https://bugs.launchpad.net/curtin/+bug/1796292/+subscriptions > -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1796292 Title: Tight timeout for bcache removal causes spurious failures To manage notifications about this bug go to: https://bugs.launchpad.net/curtin/+bug/1796292/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
