Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755884AbbHGHdd (ORCPT ); Fri, 7 Aug 2015 03:33:33 -0400 Received: from verein.lst.de ([213.95.11.211]:53526 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755472AbbHGHdc (ORCPT ); Fri, 7 Aug 2015 03:33:32 -0400 Date: Fri, 7 Aug 2015 09:33:30 +0200 From: Christoph Hellwig To: Ming Lei Cc: Hannes Reinecke , Jens Axboe , Alexander Graf , Christoph Hellwig , Linux Kernel Mailing List Subject: Re: [PATCH 0/4] loop: enable different physical blocksizes Message-ID: <20150807073330.GB17618@lst.de> References: <1437118027-94602-1-git-send-email-hare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1059 Lines: 20 On Mon, Jul 27, 2015 at 06:40:57AM -0400, Ming Lei wrote: > On Fri, Jul 17, 2015 at 3:27 AM, Hannes Reinecke wrote: > > Currently the loop driver just simulates 512-byte blocks. When > > creating images for virtual machines it might be required to use > > a different physical blocksize (eg 4k for S/390 DASD). > > Looks 'qemu-img create' doesn't have parameter of block size, > so could you share your use case? And I am just curious why > 512-byte can't work for this case. The use case is to suppot 4k sectors sizes such as DASDs usually provide, or just to create a 4k block device to check your filesystem of choice handles 4k sectors just fine. Replace 4k with other sector sizes of your choice for added benefit. In addition to the DASD use case it's really a very useful debugging tool. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/