On Thu, Jul 06, 2017 at 04:31:52PM -0700, Marc MERLIN wrote: > On Thu, Jul 06, 2017 at 04:01:41PM -0700, Omar Sandoval wrote: > > What doesn't add up about your bug report is that your CURRENT points to > > a MANIFEST-010814 way behind all of the other files in that directory, > > which are numbered 022745+. If there were a bug here, I'd expect the > > stale MANIFEST file would be one older than the new one. The filenames > > seem to be allocated sequentially, so that old MANIFEST file CURRENT > > refers to must be really old, which doesn't make sense. I don't see how > > Btrfs would screw that up :) I'd be interested to see if you can make > > the same condition trigger again. > > > > First, thanks for looking at it. > > Second, you are right on the numbers being so far apart that something was > wrong. I checked my snapshots, and I've been carrying that MANIFEST-010814 > for a long time. > In other words, it's a old stale manifest that never got deleted. > > The new real old one apparently got deleted, the new one was created but > didn't make it to disk, but the pointer in CURRENT did get repointed to the > new one that never made it to actual disk. > > So I think what happened is something like this: > MANIFEST-new got created > echo MANIFEST-new > CURRENT > MANIFEST-old got deleted > system crashed > > MANIFEST-old was indeed deleted, and MANIFEST-new never made it to disk. > > Does that sound more plausible?
In the bug report, you commented that CURRENT contained MANIFEST-010814, is that indeed the case or was it actually something newer? If it was the newer one, then it's still tricky how we'd end up that way but not as outlandish. > As for redoing this at will, apparently I may have been hit by the skylake > hyperthreading CPU bug that I just installed a microcode update for, which > was causing random crashes, which hopefully are now solved. > I can't say if those in turn messed with btrfs writing data, but I'd rather > not recreate this since it's my real filesystem I care about and don't want > to corrupt on purpose :) Understandable :) > That said, the google-chrome on my previous haswell CPU also had routine > problems when restarting chrome, although at this point I don't know if they > were due to leveldb or sqlite or something else. > I'm just mentioning this to say that I'm pretty sure that the haswell HT bug > isn't the sole culprit of this problem, likely just the trigger of some of > my crashes. > > Hope this helps > Marc > -- > "A mouse is a device used to point at the xterm you want to type in" - A.S.R. > Microsoft is to operating systems .... > .... what McDonalds is to gourmet > cooking > Home page: http://marc.merlins.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
