From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tore Anderson Subject: Re: Disabling dev_loss_tmo? Date: Wed, 14 Nov 2007 16:38:58 +0100 Message-ID: <473B1692.8050606@linpro.no> References: <47396A5B.5040001@linpro.no> <4739CE69.3040602@emulex.com> <473AAD88.307@linpro.no> <473B0644.3090403@emulex.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mailhub.linpro.no ([213.236.139.167]:48999 "EHLO mailhub.linpro.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758464AbXKNPjB (ORCPT ); Wed, 14 Nov 2007 10:39:01 -0500 In-Reply-To: <473B0644.3090403@emulex.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James.Smart@Emulex.Com Cc: Linux SCSI Mailing List , Michael Reed , Christoph Hellwig , MLOEHR@de.ibm.com * James Smart > Please don't shoot the messenger. I was trying to summarize the > evolution of FC into the kernel, highlight that the DM team knew of > the issue, had higher-priority issues, and that it applies to more > than FC. Having experienced first-hand this method of getting work > done, I certainly don't promote it as a productive way of doing > things. Sorry, didn't mean to shoot you! ;-) I mean "you" in the plural sense= ; =C2=AByou SCSI people=C2=BB - got the impression there is some kind of = disdain towards the DM team (which would indeed be a counter-productive way of getting things done). Not my intention to offend anyone, and if I did anyway I apologise. It's just frusterating when things don't work... > I'm highlighting that - ok today, we get FC working, but then the > user puts DM on something else, like iSCSI or SAS/whatever, then it > too breaks - and that's ok ? Of course the best would be if it worked perfectly with all transports, and leaving things broken is of course not OK. In my strictly pragmati= c opinion, though, having a functional DM+FC combo and and half-functiona= l DM+ combos is better than having _only_ half-functional combos. > Using this analogy, to resolve the reuse-after-free issues, we simply > would have used the dont-tear-down patches to avoid teardown bugs,=20 > like what the distros did. This too is a bad approach. Things need > to get fixed where things need to get fixed. We can add the FC > patch, but DM still needs to get fixed. Best would to have DM-multipath handle the disconnects gracefully, of course. But since it doesn't appear to be happening anytime soon: A workaround provided by the transport layer would be very welcome! I don't use iSCSI or SAS with DM so I don't know if such a workaround is wanted there too, but with FC it is necessary. Even if it is a bad approach it is much better than nothing, the way I see it. Regards --=20 Tore Anderson - To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html