On Sun, Jan 26, 2014 at 5:07 PM, Philip Guenther <guent...@gmail.com> wrote: > On Sun, Jan 26, 2014 at 11:40 AM, emigrant <emig...@gmail.com> wrote: >> My Master machine is dead, exactly HDD(thank you God for CARP+pfsync) :). >> >> root@master[/etc]wd0(pciide0:0:0): timeout >> type: ata >> c_bcount: 16384 >> c_skip: 0 > ... >> /: got error 5 while accessing filesystem >> panic: softdep_deallocate_dependencies: unrecovered I/O error >> Stopped at Debugger+0x4: popl %ebp >> RUN AT LEAST 'trace' AND 'ps' AND INCLUDE OUTPUT WHEN REPORTING THIS PANIC! >> DO NOT EVEN BOTHER REPORTING THIS WITHOUT INCLUDING THAT INFORMATION! >> ddb> > > This is a fundamental problem of softdeps:it can delay an operation to > a point where other operations depend on it in a such a way that if > the I/O for that first operation fails, the dependent operations > cannot be undone and the failure propagated up safely. Rather than > live a lie, it'll panic the system and die.
the way the decision to panic() was stated implies that the course of action is justified, when detaching the disk/hub, or forcefully mounting it read only, are alternatives that could be explored the other day I unplugged the power connector from a malfunctioning DVD-RW drive that was being too darn noisy. the kernel proceeded to detach the ahci device hosting the aformentioned drive and an sd with mounted ffs partitions i could've unplugged the power connector in the middle of a string of metadata writes to the sd. does that entail that the system should panic? hopefully the current outcome will remain, because it's way more useful than my pc throwing a hissy's fits. > > I don't know exactly which operations can lead to that; if you need to > know that you should go read the softdeps papers on Kirk McKusick's > site. > > > Philip Guenther
