From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 372F3C3A59E for ; Mon, 2 Sep 2019 15:25:52 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 136B721881 for ; Mon, 2 Sep 2019 15:25:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 136B721881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=driverdev-devel-bounces@linuxdriverproject.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id E193B87D28; Mon, 2 Sep 2019 15:25:51 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Nn4jdllP-d0w; Mon, 2 Sep 2019 15:25:49 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by hemlock.osuosl.org (Postfix) with ESMTP id CF14D87CEE; Mon, 2 Sep 2019 15:25:49 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by ash.osuosl.org (Postfix) with ESMTP id DA1421BF32D for ; Mon, 2 Sep 2019 15:25:48 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id D5E8C85FB4 for ; Mon, 2 Sep 2019 15:25:48 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6L2oPvoUZCV6 for ; Mon, 2 Sep 2019 15:25:47 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from huawei.com (szxga08-in.huawei.com [45.249.212.255]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 9901985F89 for ; Mon, 2 Sep 2019 15:25:47 +0000 (UTC) Received: from DGGEMM404-HUB.china.huawei.com (unknown [172.30.72.57]) by Forcepoint Email with ESMTP id 63347F3EFAF56709ABD5; Mon, 2 Sep 2019 23:25:44 +0800 (CST) Received: from dggeme762-chm.china.huawei.com (10.3.19.108) by DGGEMM404-HUB.china.huawei.com (10.3.20.212) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 2 Sep 2019 23:25:44 +0800 Received: from architecture4 (10.140.130.215) by dggeme762-chm.china.huawei.com (10.3.19.108) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Mon, 2 Sep 2019 23:25:43 +0800 Date: Mon, 2 Sep 2019 23:24:52 +0800 From: Gao Xiang To: Christoph Hellwig Subject: Re: [PATCH v6 03/24] erofs: add super block operations Message-ID: <20190902152451.GC179615@architecture4> References: <20190802125347.166018-1-gaoxiang25@huawei.com> <20190802125347.166018-4-gaoxiang25@huawei.com> <20190829101545.GC20598@infradead.org> <20190901085452.GA4663@hsiangkao-HP-ZHAN-66-Pro-G1> <20190902125109.GA9826@infradead.org> <20190902144303.GF2664@architecture4> <20190902151910.GA14009@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190902151910.GA14009@infradead.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.140.130.215] X-ClientProxiedBy: dggeme710-chm.china.huawei.com (10.1.199.106) To dggeme762-chm.china.huawei.com (10.3.19.108) X-CFilter-Loop: Reflected X-BeenThere: driverdev-devel@linuxdriverproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Driver Project Developer List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jan Kara , Amir Goldstein , Dave Chinner , David Sterba , Miao Xie , devel@driverdev.osuosl.org, Stephen Rothwell , "Darrick J . Wong" , Chao Yu , Alexander Viro , Jaegeuk Kim , Theodore Ts'o , Pavel Machek , Linus Torvalds , LKML , Li Guifu , Fang Wei , Greg Kroah-Hartman , linux-fsdevel@vger.kernel.org, Andrew Morton , linux-erofs@lists.ozlabs.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" Hi Christoph, On Mon, Sep 02, 2019 at 08:19:10AM -0700, Christoph Hellwig wrote: > On Mon, Sep 02, 2019 at 10:43:04PM +0800, Gao Xiang wrote: > > Hi Christoph, > > > > ... > > > > 24 __le32 features; /* (aka. feature_compat) */ > > > > ... > > > > 38 __le32 requirements; /* (aka. feature_incompat) */ > > > > ... > > > > 41 }; > > > > > > This is only cosmetic, why not stick to feature_compat and > > > feature_incompat? > > > > Okay, will fix. (however, in my mind, I'm some confused why > > "features" could be incompatible...) > > The feature is incompatible if it requires changes to the driver. > An easy to understand historic example is that ext3 originally did not > have the file types in the directory entry. Adding them means old > file system drivers can not read a file system with this new feature, > so an incompat flag has to be added. Got it. > > > > > > > + memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid)); > > > > > > + memcpy(sbi->volume_name, layout->volume_name, > > > > > > + sizeof(layout->volume_name)); > > > > > > > > > > s_uuid should preferably be a uuid_t (assuming it is a real BE uuid, > > > > > if it is le it should be a guid_t). > > > > > > > > For this case, I have no idea how to deal with... > > > > I have little knowledge about this uuid stuff, so I just copied > > > > from f2fs... (Could be no urgent of this field...) > > > > > > Who fills out this field in the on-disk format and how? > > > > mkfs.erofs, but this field leaves 0 for now. Is that reasonable? > > (using libuuid can generate it easily...) > > If the filed is always zero for now please don't fill it out. If you > decide it is worth adding the uuid eventually please add a compat > feature flag that you have a valid uuid and only fill out the field > if the file system actualy has a valid uuid. Okay. Will do that then (as a note here). Thanks, Gao Xiang _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel