From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56861) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T64ui-0004KJ-J3 for qemu-devel@nongnu.org; Mon, 27 Aug 2012 15:23:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T64ug-0006dk-B0 for qemu-devel@nongnu.org; Mon, 27 Aug 2012 15:23:56 -0400 Received: from paradis.irqsave.net ([109.190.18.76]:54477) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T64ug-0006dW-0X for qemu-devel@nongnu.org; Mon, 27 Aug 2012 15:23:54 -0400 Date: Mon, 27 Aug 2012 21:23:49 +0200 From: =?iso-8859-1?Q?Beno=EEt?= Canet Message-ID: <20120827192348.GC4498@irqsave.net> References: <1346052629-15686-1-git-send-email-benoit@irqsave.net> <1346052629-15686-10-git-send-email-benoit@irqsave.net> <503BB684.5000007@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <503BB684.5000007@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC V5 09/11] quorum: Add quorum_getlength(). List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: kwolf@redhat.com, =?iso-8859-1?Q?Beno=EEt?= Canet , stefanha@linux.vnet.ibm.com, qemu-devel@nongnu.org, blauwirbel@gmail.com, pbonzini@redhat.com Le Monday 27 Aug 2012 =E0 12:03:48 (-0600), Eric Blake a =E9crit : > On 08/27/2012 01:30 AM, Beno=EEt Canet wrote: > > Signed-off-by: Benoit Canet > > --- > > block/quorum.c | 24 ++++++++++++++++++++++++ > > 1 file changed, 24 insertions(+) >=20 > Say I'm using a 2/3 quorum. What happens if: >=20 > image A and B agree on initial content, but not length > image B and C agree on length, but not content >=20 > Does disagreeing with quorum consensus invalidate that member of the > quorum from influencing further decisions? If there is a length > discrepancy, should we declare the quorum failed rather than relying on > a mere majority vote? Or, if there is a length discrepancy, does > reading the contents beyond the end of the shorter files consider the > contents to be okay if the longer files have only NUL bytes in the extr= a > length? I'm worried that you haven't fully thought through all the > scenarios here. True, Maybe I shoud just check that every quorum file have the same length and return 0 on error. This way the quorum in disabled in case of length discrepancy. >=20 > --=20 > Eric Blake eblake@redhat.com +1-919-301-3266 > Libvirt virtualization library http://libvirt.org >=20