On Fri, Oct 07, 2016 at 05:26:27PM +0800, Qu Wenruo wrote: > > > At 10/07/2016 05:18 PM, Dave Chinner wrote: > >On Thu, Oct 06, 2016 at 04:12:56PM +0800, Qu Wenruo wrote: > >>Hi, > >> > >>Just as the title says, for some case(OK, btrfs again) we need to > >>catch a file system in special timing. > >> > >>In this specific case, we need to grab a btrfs image undergoing > >>balancing, just before the balance finished. > >> > >>Although we can use flakey to drop all write, we still don't have > >>method to catch the timing of the that transaction. > >> > >> > >>On the other hand, we can tweak our local kernel, adding > >>msleep()/message and dump the disk during the sleep. > >>And the image I dumped can easily trigger btrfs kernel and user-space bug. > >> > >>So I'm wondering if I can just upload a zipped raw image as part of > >>the test case? > > > >Preferably not. We've managed to avoid pre-built images in xfstests > >for 15 years, so there'd have to be a really good reason to start > >doing this, especially as once we open that floodgate we'll end up > >with everyone wanting to do this and it will blow out the size of > >the repository in now time. > > Makes sense. > For btrfs-progs, which includes test images, it already takes about > 77M, even we have tried our best to reduce image size. > > > > >If the issue is just timing or being unable to trigger an error > >at the right time, this is what error injection frameworks or > >debug-only sysfs hooks are for. The XFS kernel code has both, > >xfstests use both, and they pretty much do away with the need for > >custom binary filesystem images for such testing... > > So again, btrfs is lacking infrastructure for debug. > It seems that we can only rely on images out of xfstest tree, That's the /wrong answer/. Go and implement debug infrastructure that btrfs needs - if you wait for someone else to do it, it will never get done and btrfs will never stabilise.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
