Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752318AbaKFR0T (ORCPT ); Thu, 6 Nov 2014 12:26:19 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:39286 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbaKFR0Q (ORCPT ); Thu, 6 Nov 2014 12:26:16 -0500 To: Boaz Harrosh Cc: "Martin K. Petersen" , Jens Axboe , Matthew Wilcox , Dmitry Monakhov , linux-kernel , linux-fsdevel , Karel Zak Subject: Re: [PATCH 4/5] brd: Request from fdisk 4k alignment From: "Martin K. Petersen" Organization: Oracle Corporation References: <545A2D69.8090003@plexistor.com> <545A2F52.3040303@plexistor.com> <545A379D.30608@plexistor.com> Date: Thu, 06 Nov 2014 12:25:56 -0500 In-Reply-To: <545A379D.30608@plexistor.com> (Boaz Harrosh's message of "Wed, 05 Nov 2014 16:43:41 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Boaz" == Boaz Harrosh writes: Boaz, Boaz> Note that blk_queue_physical_block_size() also trashes io_min, but Boaz> we can leave this one to be 512. io_min as opposed to Boaz> physical_block_size will actually change Kernel behavior >> Care to elaborate? I wanted you to elaborate on how io_min changes kernel behavior. >> Also, fdisk and parted should be aligning on 1MB by default >> regardless of block size. So I'm also not sure why you need to trick >> fdisk to align by setting the pbs. Boaz> fdisk will not align partition-start on 1M, only the very Boaz> first-sector, libgparted and cfdisk are as you say, but with fdisk Boaz> if you put any odd numbered partition-size, the next start-sector Boaz> will just be the sum, but with this patch it will offer a small Boaz> hole and will align the partition-start on 4K. (And even with Boaz> this patch user can enter bad values) It really sounds like either your fdisk is way too old or you are running it in DOS compat mode. I don't have a fundamental issue reporting pbs of 4K. But if you are only doing it to force a certain partition alignment then it sounds like a kernel fix for a userland problem. I've CC:ed Karel who can comment on fdisk partition alignment issues. -- Martin K. Petersen Oracle Linux Engineering -- 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/