Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:44748 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755027Ab2FKOVu convert rfc822-to-8bit (ORCPT ); Mon, 11 Jun 2012 10:21:50 -0400 From: "Adamson, Andy" To: Benny Halevy CC: Boaz Harrosh , "Welch, Brent" , "Bhamare, Sachin" , "Adamson, Andy" , Andy Adamson , "Myklebust, Trond" , "" , "Huang, James" Subject: Re: [PATCH 2/3] NFSv4.1 mark layout when already returned Date: Mon, 11 Jun 2012 14:21:33 +0000 Message-ID: <47AB2031-76C2-4E10-9C55-D328E2994780@netapp.com> References: <1338571178-2096-1-git-send-email-andros@netapp.com> <1338571178-2096-2-git-send-email-andros@netapp.com> <4FCA98E7.2030006@panasas.com> <1C92D18B-1977-4A12-A4DA-84DAC4B3E81E@netapp.com> <4FCE1DC1.6050100@panasas.com> <4FD5C0EA.806@tonian.com> <4FD5CBF6.6030800@panasas.com> <4FD5FAEF.5040004@tonian.com> In-Reply-To: <4FD5FAEF.5040004@tonian.com> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Jun 11, 2012, at 10:04 AM, Benny Halevy wrote: > On 2012-06-11 13:44, Boaz Harrosh wrote: >> On 06/11/2012 12:56 PM, Benny Halevy wrote: >> >>> >>> It will for recovering files striped with RAID as the LAYOUTRETURN >>> provides the server with a reliable "commit point" where it knows >>> exactly what was written successfully to each stripe and can make >>> the most efficient decision about recovering it (if needed). >>> >>> Allowing I/O to the stripe post LAYOUTRETURN may result in data >>> corruption due to parity inconsistency. >>> >> >> >> The fact of the matter is that we - object guys - Which care about >> LAYOUTRETURN the most, have neglected to notice and fix the current >> situation which is even worse than After Andy's patch. Which will >> send multiple LAYOUTRETURNs on the same layout, and might still >> continue IO on returned layouts. >> >> Thanks Andy for testing and highlighting the current problem, >> I will prioritized this development internally at Panasas and >> will work on a solution ASAP. I hope one that will satisfy >> all. >> >> Basically my plan is to postpone the LAYOUTRETURN send to >> when the segment is last referenced, if a flag was set to >> do so, and make sure reference counting is done proper, so >> after flag set the last IO_done will send the LAYOUTRETURN. >> >> If that is OK with all I hope? > > Sounds OK to me. Thanks! Sounds fine to me as well, for LAYOUTRETURN during normal behavior. -->Andy > > Benny > >> >>> Benny >>> >> >> >> Thanks >> Boaz >>