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spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-84-NIpDY3SIO2O6wr30VL1vUw-1; Fri, 20 Nov 2020 10:33:24 -0500 X-MC-Unique: NIpDY3SIO2O6wr30VL1vUw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 71779EC1AB; Fri, 20 Nov 2020 15:33:08 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7CCD25D6CF; Fri, 20 Nov 2020 15:33:07 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 2EDBF5002D; Fri, 20 Nov 2020 15:33:05 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0AKFX28k018280 for ; Fri, 20 Nov 2020 10:33:02 -0500 Received: by smtp.corp.redhat.com (Postfix) id 223AD2166B2B; Fri, 20 Nov 2020 15:33:02 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast01.extmail.prod.ext.rdu2.redhat.com [10.11.55.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1D3C32166B2D for ; Fri, 20 Nov 2020 15:33:00 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id F2549857022 for ; Fri, 20 Nov 2020 15:32:59 +0000 (UTC) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-113-uCkzhl4AOJuHa4B85zMjTw-1; Fri, 20 Nov 2020 10:32:57 -0500 X-MC-Unique: uCkzhl4AOJuHa4B85zMjTw-1 Received: by verein.lst.de (Postfix, from userid 2407) id ED47B67373; Fri, 20 Nov 2020 16:32:53 +0100 (CET) Date: Fri, 20 Nov 2020 16:32:53 +0100 From: Christoph Hellwig To: Jan Kara Message-ID: <20201120153253.GA18990@lst.de> References: <20201118084800.2339180-1-hch@lst.de> <20201118084800.2339180-15-hch@lst.de> <20201119120525.GW1981@quack2.suse.cz> <20201120090820.GD21715@lst.de> <20201120112121.GB15537@quack2.suse.cz> MIME-Version: 1.0 In-Reply-To: <20201120112121.GB15537@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: dm-devel@redhat.com Cc: Jens Axboe , Mike Snitzer , Konrad Rzeszutek Wilk , Richard Weinberger , Josef Bacik , Coly Li , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, linux-mtd@lists.infradead.org, linux-mm@kvack.org, Jan Kara , Tejun Heo , xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, Christoph Hellwig Subject: Re: [dm-devel] [PATCH 14/20] block: remove the nr_sects field in struct hd_struct X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Nov 20, 2020 at 12:21:21PM +0100, Jan Kara wrote: > > > AFAICT bd_size_lock is pointless after these changes so we can just remove > > > it? > > > > I don't think it is, as reuqiring bd_mutex for size updates leads to > > rather awkward lock ordering problems. > > OK, let me ask differently: What is bd_size_lock protecting now? Ah, I see, > on 32-bit it is needed to prevent torn writes to i_size, right? Exactly. In theory we could skip it for 64-bit, but as updating the size isn't a fast path, and struct block_device isn't super size critical I'd rather keep the same code for 32 vs 64-bit builds. -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel 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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 6006FC6379F for ; Fri, 20 Nov 2020 15:33:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1821322D0A for ; Fri, 20 Nov 2020 15:33:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727983AbgKTPc7 (ORCPT ); Fri, 20 Nov 2020 10:32:59 -0500 Received: from verein.lst.de ([213.95.11.211]:43415 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728264AbgKTPc6 (ORCPT ); Fri, 20 Nov 2020 10:32:58 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id ED47B67373; Fri, 20 Nov 2020 16:32:53 +0100 (CET) Date: Fri, 20 Nov 2020 16:32:53 +0100 From: Christoph Hellwig To: Jan Kara Cc: Christoph Hellwig , Jens Axboe , Tejun Heo , Josef Bacik , Konrad Rzeszutek Wilk , Coly Li , Mike Snitzer , dm-devel@redhat.com, Richard Weinberger , Jan Kara , linux-block@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 14/20] block: remove the nr_sects field in struct hd_struct Message-ID: <20201120153253.GA18990@lst.de> References: <20201118084800.2339180-1-hch@lst.de> <20201118084800.2339180-15-hch@lst.de> <20201119120525.GW1981@quack2.suse.cz> <20201120090820.GD21715@lst.de> <20201120112121.GB15537@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120112121.GB15537@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On Fri, Nov 20, 2020 at 12:21:21PM +0100, Jan Kara wrote: > > > AFAICT bd_size_lock is pointless after these changes so we can just remove > > > it? > > > > I don't think it is, as reuqiring bd_mutex for size updates leads to > > rather awkward lock ordering problems. > > OK, let me ask differently: What is bd_size_lock protecting now? Ah, I see, > on 32-bit it is needed to prevent torn writes to i_size, right? Exactly. In theory we could skip it for 64-bit, but as updating the size isn't a fast path, and struct block_device isn't super size critical I'd rather keep the same code for 32 vs 64-bit builds. 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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 CBA67C2D0E4 for ; Fri, 20 Nov 2020 15:34:16 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 4FDA922D0A for ; Fri, 20 Nov 2020 15:34:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="w/vFJb89" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FDA922D0A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kxEDPGiR7SCdiPS5ep0Oe2C/TfS6WYV/pDgWiUslnyg=; b=w/vFJb896rfCcfMm9oHb88a0v 8MsHtgQobmmR7OCeCLq8bhgLfqt5BXx67ZN0JY2W76gwK/SdQnOkC0N4Wrxroiq5QhiW2CB5zCM+u saRnnaE4YuXYfBs9IuJGj/zmUqHq17vKmZzc8lZrB43ifpq5i4NrWVbExs/gEU1VJohjWqPhb/XgZ eXejnRWSLWOoBeR8HtVBMpP3nLH5PLVUTAjazLJZVbmTWp4vTh1xqckgh/htwBYNJuoy7sZUubi29 agCm3ulrAtqTdLKo4F1vauRZOCj+Cw9mRQHXlbxAuCyav9XM696Sm1QNZGtPfj8Jf647XxlnmmrYU FUvhX2Aow==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg8Pb-0007ui-Ok; Fri, 20 Nov 2020 15:33:23 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg8PC-0007lz-VM for linux-mtd@lists.infradead.org; Fri, 20 Nov 2020 15:33:00 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id ED47B67373; Fri, 20 Nov 2020 16:32:53 +0100 (CET) Date: Fri, 20 Nov 2020 16:32:53 +0100 From: Christoph Hellwig To: Jan Kara Subject: Re: [PATCH 14/20] block: remove the nr_sects field in struct hd_struct Message-ID: <20201120153253.GA18990@lst.de> References: <20201118084800.2339180-1-hch@lst.de> <20201118084800.2339180-15-hch@lst.de> <20201119120525.GW1981@quack2.suse.cz> <20201120090820.GD21715@lst.de> <20201120112121.GB15537@quack2.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201120112121.GB15537@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201120_103259_204540_649882FA X-CRM114-Status: GOOD ( 12.47 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Mike Snitzer , Konrad Rzeszutek Wilk , Richard Weinberger , Josef Bacik , Coly Li , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, linux-mtd@lists.infradead.org, linux-mm@kvack.org, Jan Kara , Tejun Heo , xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Fri, Nov 20, 2020 at 12:21:21PM +0100, Jan Kara wrote: > > > AFAICT bd_size_lock is pointless after these changes so we can just remove > > > it? > > > > I don't think it is, as reuqiring bd_mutex for size updates leads to > > rather awkward lock ordering problems. > > OK, let me ask differently: What is bd_size_lock protecting now? Ah, I see, > on 32-bit it is needed to prevent torn writes to i_size, right? Exactly. In theory we could skip it for 64-bit, but as updating the size isn't a fast path, and struct block_device isn't super size critical I'd rather keep the same code for 32 vs 64-bit builds. ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/