From: Chris Mason Subject: Re: hunt for 2.6.37 dm-crypt+ext4 corruption? (was: Re: dm-crypt barrier support is effective) Date: Tue, 07 Dec 2010 13:52:33 -0500 Message-ID: <1291747731-sup-3099@think> References: <4CF692D1.1010906@redhat.com> <4CF6B3E8.2000406@redhat.com> <20101201212310.GA15648@redhat.com> <20101204193828.GB13871@redhat.com> <20101207142145.GA27861@think> <20101207182243.GB21112@redhat.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Mike Snitzer , Matt , Milan Broz , Andi Kleen , linux-btrfs , dm-devel , Linux Kernel , htd , htejun , linux-ext4 To: Jon Nelson Return-path: Received: from rcsinet10.oracle.com ([148.87.113.121]:21044 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752665Ab0LGTBu (ORCPT ); Tue, 7 Dec 2010 14:01:50 -0500 In-reply-to: Sender: linux-ext4-owner@vger.kernel.org List-ID: Excerpts from Jon Nelson's message of 2010-12-07 13:45:14 -0500: > On Tue, Dec 7, 2010 at 12:22 PM, Mike Snitzer wr= ote: > > On Tue, Dec 07 2010 at =C2=A01:10pm -0500, > > Jon Nelson wrote: > > > >> I finally found some time to test this out. With 2.6.37-rc4 (openS= USE > >> KOTD kernel) I easily encounter the issue. > >> > >> Using a virtual machine, I created a stock, minimal openSUSE 11.3 = x86_64 > >> install, installed all updates, installed postgresql and the 'KOTD= ' > >> (Kernel of the Day) > >> kernel, and ran the following tests (as postgres user because I'm > >> lazy). > >> > >> 1. create a database (from bash): > >> > >> createdb test > >> > >> 2. place the following contents in a file (I used 't.sql'): > >> > >> begin; > >> create temporary table foo as select x as a, ARRAY[x] as b FROM > >> generate_series(1, 10000000 ) AS x; > >> create index foo_a_idx on foo (a); > >> create index foo_b_idx on foo USING GIN (b); > >> rollback; > >> > >> 3. execute that sql: > >> > >> psql -f t.sql --echo-all test > >> > >> > >> With 2.6.34.7 I can re-run [3] all day long, as many times as I wa= nt, > >> without issue. > >> > >> With 2.6.37-rc4-13 (the currently-installed KOTD kernel) if tails > >> pretty frequently. > > > > How does it fail? =C2=A0postgres errors? =C2=A0kernel errors? >=20 > postgresql errors. Typically, header corruption but from the limited > visibility I've had into this via strace, what I see is zeroed pages > where there shouldn't be. This sounds a lot like a bug higher up than dm-crypt. Zeros tend to come from some piece of code explicitly filling a page with zeros, and that often happens in the corner cases for O_DIRECT and a few other places in the filesystem. Have you tried triggering this with a regular block device? -chris -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html