On Mon, 18 May 2015, Abelardo Ricart III wrote: > On Fri, 2015-05-15 at 08:04 -0700, Brandon Smith wrote: > > On 2015-05-01 (Fri) at 19:42:15 -0400, Abelardo Ricart III wrote: > > > > > The patchset in question was tested quite heavily so this is a > > > > > surprising report. I'm noticing you are opting in to dm-crypt discard > > > > > support. Have you tested without discards enabled? > > > > > > > > I've disabled discards universally and rebuilt a vanilla kernel. After > > > > running > > > > my heavy read-write-sync scripts, everything seems to be working fine now. > > > > I > > > > suppose this could be something that used to fail silently before, but now > > > > produces bad behavior? I seem to remember having something in my message > > > > log > > > > about "discards not supported on this device" when running with it enabled > > > > before. > > > > > > Forgive me, but I spoke too soon. The corruption and libata errors are still > > > there, as was evidenced when I went to reboot and got treated to an eye full > > > of > > > "read-only filesystem" and ata errors. > > > > > > So no, disabling discards unfortunately did nothing to help. > > > > I've been experiencing the same problem. Vanilla 4.0 series kernels, > > dm-crypt, with/or without discards, on a ThinkPad X1 Carbon with a > > LiteOn LGT-256M6G SSD. > > > > After some of googling around, I found some chatter relating to changes > > in NCQ on SSDs in 4.0. Been running w/o NCQ for a full kernel build so > > far without issue. Perhaps there's been some change in the interaction > > between dm-crypt and NCQ? > > > > Abelardo, can you try w/o NCQ and see if that helps your situation? > > > > Best, > > > > --Brandon > > I've been running with NCQ disabled and been stress testing for awhile and the > issue is indeed gone. Thanks for the workaround! > > So it seems the issue is somehow related to the combination of NCQ, dm-crypt, > and possibly (some?) SSDs. Hi I suspect that this is a bug in kernel NCQ processing or in SSD firmware and recent dm-crypt changes made the bug show up. I suggest this: If you have some test that reliably reproduces the bug, please do this: take kernel 3.19 or 3.18 and apply dm-crypt parallelization patches (commits f3396c58fd8442850e759843457d78b6ec3a9589, cf2f1abfbd0dba701f7f16ef619e4d2485de3366, 7145c241a1bf2841952c3e297c4080b357b3e52d, 94f5e0243c48aa01441c987743dc468e2d6eaca2, dc2676210c425ee8e5cb1bec5bc84d004ddf4179, 0f5d8e6ee758f7023e4353cca75d785b2d4f6abe, b3c5fd3052492f1b8d060799d4f18be5a5438add) on it. If the bug doesn't show up with the older kernel and dm-crypt parallelization patches, use git bisect to find out which patch broken NCQ. When you test a kernel with bisect, apply the above mentioned patches to it. Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
