Christian Robert posted on Fri, 24 Feb 2012 21:47:20 -0500 as excerpted: > wrong, I tryed to wait until "Load average" got near to zero (couple of > minutes) > before unmounting and it changed nothing. None of thoses subvolumes have > any data inside so deleting should be trivial and quick. > > Got the kernel backtrace "while" doing the deletes. Not after. Please don't top post. It makes replying in context nearly impossible. Here, I quote your reply, but the context in which it was made gets lost because you top-posted instead of replying inline, at the appropriate place based on context, or bottom-posting if it's not /too/ long (it isn't, bottom posting would have been fine, in this case) and you can't be bothered to trim to context appropriately. cwillu is correct. The subvolume deletes do happen in the background and it can delay unmounting, in cases like this 10K subvolumes scenario, significantly. There was some discussion of that recently on another thread, along with a patch so the unmounting is allowed (for shutdown, etc) and the cleanup picked up again after remounting, But it was recent enough the patch will have only just made it into 3.3-prerelease kernel mainline (probably with Chris's pull request to Linus from less than 12 hours ago, as CCed to this list, I'm not sure Linus has actually pulled it yet), or may be delayed until the 3.4 commit window. Never-the-less, you have a point about the backtraces happening while doing the deletes. That's a problem that the allow unmount and finish cleanup later patch wouldn't have addressed by itself, but it's possible other recent patches address it (especially since the pull includes a lot of fixes based on Oracle's current intensive btrfs internal QA testing), so I'd suggest doing a git pull in a few hours, checking that Linus has applied Chris's pull request (this assumes you're running mainline kernel, of course), and after that's applied and you're running the new kernel with it, rerunning your test. If it still backtraces at that point then yeah, it's worth further investigation. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- 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
