From: Badari Pulavarty Subject: Re: [RFC][PATCH] set_page_buffer_dirty should skip unmapped buffers Date: Fri, 08 Sep 2006 07:35:22 -0700 Message-ID: <45017FAA.1070203@us.ibm.com> References: <20060906124719.GA11868@atrey.karlin.mff.cuni.cz> <1157555559.23501.25.camel@dyn9047017100.beaverton.ibm.com> <20060906153449.GC18281@atrey.karlin.mff.cuni.cz> <1157559545.23501.30.camel@dyn9047017100.beaverton.ibm.com> <20060906162723.GA14345@atrey.karlin.mff.cuni.cz> <1157563016.23501.39.camel@dyn9047017100.beaverton.ibm.com> <20060906172733.GC14345@atrey.karlin.mff.cuni.cz> <1157641877.7725.13.camel@dyn9047017100.beaverton.ibm.com> <20060907223048.GD22549@atrey.karlin.mff.cuni.cz> <4500F2B2.4010204@us.ibm.com> <20060908082531.GA28397@atrey.karlin.mff.cuni.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Anton Altaparmakov , sct@redhat.com, linux-fsdevel , lkml , ext4 Return-path: Received: from e32.co.us.ibm.com ([32.97.110.150]:46293 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750758AbWIHOfc (ORCPT ); Fri, 8 Sep 2006 10:35:32 -0400 To: Jan Kara In-Reply-To: <20060908082531.GA28397@atrey.karlin.mff.cuni.cz> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Jan Kara wrote: > Hi, > > >> Jan Kara wrote: >> >>> I've been looking more at the code and I have revived my patch fixing >>> this part of the code. I've mildly tested the patch. Could you also give >>> it a try? Thanks. >>> >>> Honza >>> >>> ------------------------------------------------------------------------ >>> >>> Original commit code assumes, that when a buffer on BJ_SyncData list is >>> locked, >>> it is being written to disk. But this is not true and hence it can lead to >>> a >>> potential data loss on crash. Also the code didn't count with the fact that >>> journal_dirty_data() can steal buffers from committing transaction and >>> hence >>> could write buffers that no longer belong to the committing transaction. >>> Finally it could possibly happen that we tried writing out one buffer >>> several >>> times. >>> >>> The patch below tries to solve these problems by a complete rewrite of the >>> data >>> commit code. We go through buffers on t_sync_datalist, lock buffers needing >>> write out and store them in an array. Buffers are also immediately refiled >>> to >>> BJ_Locked list or unfiled (if the write out is completed). When the array >>> is >>> full or we have to block on buffer lock, we submit all accumulated buffers >>> for >>> IO. >>> >>> Signed-off-by: Jan Kara >>> >>> >>> >> I have been running 4+ hours with this patch and seems to work fine. I >> haven't hit any >> assert yet :) >> >> I will let it run till tomorrow. I will let you know, how it goes. >> > Great, thanks. BTW: Do you have any performance tests handy? The > changes are big enough to cause some unexpected performance regressions, > livelocks... If you don't have anything ready, I can setup and run > something myself. Just that I don't like this testing too much ;). > Tests are still running fine. I don't have any performance tests handy. We have some automated tests I can schedule to run to verify the stability aspects. Thanks, Badari