From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [Lsf10-pc] [LFS/VM TOPIC] Stable pages while IO (was Wrong DIF guard tag on ext2 write) Date: Fri, 4 Jun 2010 12:30:09 -0400 Message-ID: <20100604163009.GF10153@fieldses.org> References: <20100531112817.GA16260@schmichrtp.mainz.de.ibm.com> <4C07D3D0.8010500@panasas.com> <20100604162332.GF3414@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100604162332.GF3414@quack.suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org To: Jan Kara Cc: Boaz Harrosh , Vladislav Bolkhovitin , "Martin K. Petersen" , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, James Bottomley , Christof Schmitt , lsf10-pc@lists.linuxfoundation.org, Al Viro , linux-fsdevel@vger.kernel.org, Matthew Wilcox , Ric Wheeler , Christoph Hellwig List-Id: linux-scsi@vger.kernel.org On Fri, Jun 04, 2010 at 06:23:32PM +0200, Jan Kara wrote: > On Thu 03-06-10 19:09:52, Boaz Harrosh wrote: > > [Topic] > > How to not let pages change while in IO > > > > [Abstract] > > As seen in a long thread on the fsdvel scsi mailing lists. Lots of > > people have headaches and sleep less nights because individual pages > > can change while in IO and/or DMA. Though each one as slightly different > > needs, the mechanics look to be the same. > Hmm, I don't think it's really about "how to not let pages change" - that > is doable by using wait_on_page_writeback() in ->page_mkwrite and > ->write_begin. Will the same work for the NFS server checksumming page data in read replies? --b. > I think the discussion is more about whether we should do it > or whether we should rechecksum and resubmit IO in case of checksum failure > as Nick proposed... > > Honza > > People that care: > > - Mirror and RAID people that need on disk consistency. > > - Network storage that wants data checksum. > > - DIF/DIX people > > - ... > > > > I for one know nothing of the subject but am a RAID person and would > > like a solution that does not force me to copy the complete data load. > > > > Please lets get all the VM VFS and drivers people in one room and see > > if we can have a Linux solution to this problem > -- > Jan Kara > SUSE Labs, CR > _______________________________________________ > Lsf10-pc mailing list > Lsf10-pc@lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/lsf10-pc