From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933057AbbLHF3S (ORCPT ); Tue, 8 Dec 2015 00:29:18 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:35567 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932332AbbLHF3L (ORCPT ); Tue, 8 Dec 2015 00:29:11 -0500 Date: Mon, 7 Dec 2015 21:28:30 -0800 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Jens Axboe , "Seymour, Shane M" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-api@vger.kernel.org" , Jeff Layton , "J. Bruce Fields" , "martin.petersen@oracle.com" Subject: Re: [PATCH v4] block: create ioctl to discard-or-zeroout a range of blocks Message-ID: <20151208052830.GC10584@birch.djwong.org> References: <20151113220143.GE2217@birch.djwong.org> <20151208024015.GA18458@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151208024015.GA18458@infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 07, 2015 at 06:40:15PM -0800, Christoph Hellwig wrote: > On Fri, Nov 13, 2015 at 02:01:43PM -0800, Darrick J. Wong wrote: > > Create a new ioctl to expose the block layer's newfound ability to > > issue either a zeroing discard, a WRITE SAME with a zero page, or a > > regular write with the zero page. This BLKZEROOUT2 ioctl takes > > {start, length, flags} as parameters. So far, the only flag available > > is to enable the zeroing discard part -- without it, the call invokes > > the old BLKZEROOUT behavior. start and length have the same meaning > > as in BLKZEROOUT. > > > > Furthermore, because BLKZEROOUT2 issues commands directly to the > > storage device, we must invalidate the page cache (as a regular > > O_DIRECT write would do) to avoid returning stale cache contents at a > > later time. > > So does BLKZEROOUT. Seems like adding the cache invalidation should > be one patch and the ioctl another one. Otherwise this looks fine > except that I kinda hate BLKZEROOUT2 name, but can't come up with > anything better. I should've sent the 4.4 version -- since the ioctl code was refactored into separate functions and the new function modifies its arguments, I ended up rewriting most of the function body just to set up the page cache invalidation. (Ah, I see -- 4.4-rc1 came out and I forgot to resend.) Blergh, v5 on its way... --D > -- > To unsubscribe from this list: send the line "unsubscribe linux-api" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html