On Fri, Apr 15, 2016 at 6:07 PM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote: > On Fri, Apr 15, 2016 at 09:28:49AM -0600, Chris Murphy wrote: >> Note this is a testing VM, no user data is at risk >> >> https://bugzilla.kernel.org/show_bug.cgi?id=116331 > > From the call stack we can tell that btrfs_root_bytenr() returns 0 > somehow. And this comes from btrfs_recover_relocation() reading > the root on which reloc_root is snapshoted, and it's not the FS tree, > might be a snapshot root or subvolume root. > > Looks like our COW fails for that root. QEMU disk cache is set to unsafe, which might be a contributing factor. I've updated the bug to reflect some data loss is expected, but seems like the file system should still rollback to a known good state? And if not should be repairable. But maybe that's not a valid expectation for unsafe caching. -- Chris Murphy -- 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
