Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755711AbbGEIoI (ORCPT ); Sun, 5 Jul 2015 04:44:08 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:36108 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752078AbbGEIny (ORCPT ); Sun, 5 Jul 2015 04:43:54 -0400 Message-ID: <5598EE47.1030204@gmail.com> Date: Sun, 05 Jul 2015 11:43:51 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Christoph Hellwig , Matthew Wilcox CC: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Matthew Wilcox Subject: Re: [PATCH v2 1/6] dax: Add block size note to documentation References: <1435934443-17090-1-git-send-email-matthew.r.wilcox@intel.com> <1435934443-17090-2-git-send-email-matthew.r.wilcox@intel.com> <20150704050329.GA22452@infradead.org> In-Reply-To: <20150704050329.GA22452@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1223 Lines: 32 On 07/04/2015 08:03 AM, Christoph Hellwig wrote: > On Fri, Jul 03, 2015 at 10:40:38AM -0400, Matthew Wilcox wrote: >> From: Matthew Wilcox >> >> For block devices which are small enough, mkfs will default to creating >> a filesystem with block sizes smaller than page size. > > This seems like an odd note. At least for XFS and btrfs filesystem size > don't change block sizes. ff this is an extN oddity you're probably > better off documenting it there. > Is why I added to brd: /* This is so fdisk will align partitions on 4k, because of * direct_access API needing 4k alignment, returning a PFN * (This is only a problem on very small devices <= 4M, * otherwise fdisk will align on 1M. Regardless this call * is harmless) */ blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE); Perhaps add the same to pmem, and/or perhaps make mkfs.extX also inspect this and not create blocks smaller then physical_block_size? Thanks Boaz -- 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/