From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: [RFC/PATCH 0/7] enable honoring write cache setting of IDE drive Date: Fri, 28 Jan 2005 22:35:17 +0100 Message-ID: <58cb370e05012813357d42da46@mail.gmail.com> References: <58cb370e05012811112c3c0b@mail.gmail.com> <200501282106.j0SL6M0Z026655@falcon30.maxeymade.com> Reply-To: Bartlomiej Zolnierkiewicz Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from wproxy.gmail.com ([64.233.184.204]:527 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S262761AbVA1VfR (ORCPT ); Fri, 28 Jan 2005 16:35:17 -0500 Received: by wproxy.gmail.com with SMTP id 67so317873wri for ; Fri, 28 Jan 2005 13:35:17 -0800 (PST) In-Reply-To: <200501282106.j0SL6M0Z026655@falcon30.maxeymade.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Doug Maxey Cc: Doug Maxey , Jens Axboe , Jeff Garzik , Linux IDE Mailing List On Fri, 28 Jan 2005 15:06:22 -0600, Doug Maxey wrote: > > On Fri, 28 Jan 2005 20:11:37 +0100, Bartlomiej Zolnierkiewicz wrote: > >On Fri, 28 Jan 2005 12:16:01 -0600, Doug Maxey wrote: > > > >We have too many config options already. > > > >Behavior should be simple: > >* no cache flushes - wcache off by default > >* cache flushes - wcache on by default > >* inform user about the wcache status > >* allow changing of wcache by user > > My interpretation of what you are saying here is the selection of > "cache flush" drives the setting of wcache. Are you saying that > "barrier=off" on the boot line the currently (only and will remain) > supported method controlling flushes? No, I am saying that cache flush is a property of disk not fs. On the contrary barrier is a property of filesystem. > AFAICS, "barrier=off" just tells the FS (only ext2 and reiser) to not > flush writes. I may be misunderstanding how that controls the > behavior of the drive at the ll_blk layer. Is that what you want to > see a patch to, pick this out of the FS? No, why? > >> > >> 1) move the cache_write code to ide-io, where it will be callable from > >> kernels built without ide-disk. > > > >I've already pointed this out - this is not needed, you should add > >check similar to this for 'xfer_set'. Another reason not to do this > >is that write_cache() uses REQ_DRIVE_TASKFILE internally. > > Is taskfile going away? Quite the opposite but if you want to use taskfile, map whole ide_cmd_ioctl() to it not CACHE_FLUSH_{EXT} command only and don't intermix bugfixes with potentially risky changes.