On Thu, Mar 24, 2016 at 05:52:44PM +0100, Carlos Maiolino wrote: > I can now reproduce it, or at least part of the problem. > > Regarding your question Dave, yes, it can be unmounted after I issue xfs_io shutdown > command. But, if a umount is issued before that, then we can't find the > mountpoint anymore. > > I'm not sure if I'm correct, but, what it looks like to me, as you already > mentioned, is that we keep getting IO errors but we never actually shutdown > the filesystem while doing async metadata writes. *nod* > I believe I've found the problem. So, I will try to explain it, so you guys > can review and let me know if I'm right or not > > I was looking the code, and for me, looks like async retries are designed to > keep retrying forever, and rely on some other part of the filesystem to actually > shutdown it. *nod* [snip description of metadata IO error behaviour] Yes, that is exactly how the code is expected to behave - in fact, that's how it was originally designed to behave. > Looks like, somebody already noticed it: > > /* > ¦* If the write was asynchronous then no one will be looking for the > ¦* error. Clear the error state and write the buffer out again. > ¦* > ¦* XXX: This helps against transient write errors, but we need to find > ¦* a way to shut the filesystem down if the writes keep failing. > ¦* > ¦* In practice we'll shut the filesystem down soon as non-transient > ¦* errors tend to affect the whole device and a failing log write > ¦* will make us give up. But we really ought to do better here. > ¦*/ > > > So, if I'm write in how we hit this problem, and IIRC, Dave's patchset for > setting limits to IO errors can be slightly modified to fix this issue too, but, The patchset I have doesn't need modification to fix this issue - it has a patch specifically to address this, and it changes the default behaviour to "fail async writes at unmount": http://oss.sgi.com/archives/xfs/2015-08/msg00092.html > the problem is that the user must set it BEFORE he tries to unmount the > filesystem, otherwise it will get stuck here. Yes, but that doesn't answer the big question: why don't the periodic log forces that are failing with EIO cause a filesystem shutdown? We issue a log force every 30s even during unmount, and a failed log IO must cause the filesystem to shut down. So why aren't these causing the filesystem to shutdown as we'd expect when the device has been pulled? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
