From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e7.ny.us.ibm.com ([32.97.182.137]:47819 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799Ab2LSCaO (ORCPT ); Tue, 18 Dec 2012 21:30:14 -0500 Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 18 Dec 2012 21:30:12 -0500 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id D60C638C801C for ; Tue, 18 Dec 2012 21:29:59 -0500 (EST) Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qBJ2TxxL282734 for ; Tue, 18 Dec 2012 21:29:59 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qBJ2TwXI021763 for ; Wed, 19 Dec 2012 00:29:59 -0200 Message-ID: <50D126A5.2060101@linux.vnet.ibm.com> Date: Tue, 18 Dec 2012 18:29:57 -0800 From: Wade Cline MIME-Version: 1.0 To: bo.li.liu@oracle.com CC: miaox@cn.fujitsu.com, linux-btrfs@vger.kernel.org, cmm@linux.vnet.ibm.com Subject: Re: [PATCH] [RFC v2] Btrfs: Subpagesize blocksize (WIP). References: <1355814805-13935-1-git-send-email-clinew@linux.vnet.ibm.com> <20121218073050.GA19332@liubo.cn.oracle.com> <50D02E0A.8080505@cn.fujitsu.com> <50D0EDAA.3090202@linux.vnet.ibm.com> <20121219020242.GB14426@liubo> In-Reply-To: <20121219020242.GB14426@liubo> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 12/18/2012 06:02 PM, Liu Bo wrote: > On Tue, Dec 18, 2012 at 02:26:50PM -0800, Wade Cline wrote: >> On 12/18/2012 12:49 AM, Miao Xie wrote: >> >>> On tue, 18 Dec 2012 15:30:51 +0800, Liu Bo wrote: >>>> On Mon, Dec 17, 2012 at 11:13:25PM -0800, clinew@linux.vnet.ibm.com wrote: >>>>> From: Wade Cline >>>>> >>>>> v1 -> v2: >>>>> - Added Signed-off-by tag (it's kind of important). >>>>> >>>>> This patch is only an RFC. My internship is ending and I was hoping >>>>> to get some feedback and incorporate any suggestions people may >>>>> have before my internship ends along with life as we know it (this >>>>> Friday). >>>>> >>>>> The filesystem should mount/umount properly but tends towards the >>>>> explosive side when writes start happening. My current focus is on >>>>> checksumming issues and also an error when releasing extent buffers >>>>> when creating a large file with 'dd'... and probably any other >>>>> method. There's still a significant amount of work that needs to be >>>>> done before this should be incorporated into mainline. >>>>> >>>>> A couple of notes: >>>>> - Based off of Josef's btrfs-next branch, commit >>>>> 8d089a86e45b34d7bc534d955e9d8543609f7e42 >>>>> - C99-style comments are "meta-comments" where I'd like more >>>>> feedback; they aren't permanent but make 'checkpatch' moan. >>>>> - extent_buffer allocation and freeing need their code paths >>>>> merged; they're currently in separate functions and are both >>>>> very ugly. >>>>> - The patch itself will eventually need to be broken down >>>>> into smaller pieces if at all possible... >>>> >>>> Could you please first elaborate why we need this subpagesize stuff and >>>> any user case in this patch's commit log? >>>> Or Am I missing something? >>> >>> It is used on the machines on which the page size is larger than 4KB (Such as powerpc) >>> >>> Thanks >>> Miao >> >> Yeah. Basically, if we create a btrfs filesystem with a 4k blocksize >> then that filesystem is incompatible with architectures such as PowerPC >> and MIPS which have a page size larger than 4k. >> >> -Wade >> > > I'm just saying there _should_ be some kind of such description about > the patch in your commit log... > > That's for those who don't ever know the background of the idea. > > thanks, > liubo > Okay, I'll make sure to add that description next time I send the patch out. Thanks, Wade