From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:53505) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RTtiS-0005QH-Po for qemu-devel@nongnu.org; Fri, 25 Nov 2011 06:13:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RTtiR-0003Gw-Ug for qemu-devel@nongnu.org; Fri, 25 Nov 2011 06:13:12 -0500 Received: from verein.lst.de ([213.95.11.211]:45083 helo=newverein.lst.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RTtiR-0003Gk-QB for qemu-devel@nongnu.org; Fri, 25 Nov 2011 06:13:11 -0500 Date: Fri, 25 Nov 2011 12:13:10 +0100 From: Christoph Hellwig Message-ID: <20111125111310.GA24566@lst.de> References: <1322067087-16884-1-git-send-email-pbonzini@redhat.com> <4ECF517F.5050000@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ECF517F.5050000@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH 0/3] block: add support for 4k logical blocks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Mark Wu , qemu-devel@nongnu.org On Fri, Nov 25, 2011 at 09:27:43AM +0100, Paolo Bonzini wrote: > No, it adds support for 512b logical block sizes running on a host with 4k > logical block size and cache=none. This is suboptimal as it requires > bounce buffers, but it can happen with migration and until libvirt provides > a knob for the guest's logical block size. It's also highly dangerous becausw the fs may assume a sector is written atomically, but now it isn't. If at all I would recommend to only support this case read only.