Received: by 2002:a05:6a10:8c0a:0:0:0:0 with SMTP id go10csp370656pxb; Wed, 20 Jan 2021 08:57:31 -0800 (PST) X-Google-Smtp-Source: ABdhPJxG4fbqNDpOPdm81dOlWoJpUkjDiksYsHMiQaAG1re0vp1Fzt7xlVPKmDyRkORAKDAlwzWP X-Received: by 2002:a05:6402:3192:: with SMTP id di18mr7732456edb.332.1611161851490; Wed, 20 Jan 2021 08:57:31 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1611161851; cv=none; d=google.com; s=arc-20160816; b=etWlCjEeYplcJrDTuPVgNd0qXEZh9WL8XKyKRLfXtSEPPfMPGk7ET331K8mgJ6pezP wz4AKVPhudPvCXMMyekjGLPrIkxkZ0mt9mIV602z1NTNfDJymI5TTFejM62tE/jwfnqR UqtiQrhExjzbbIdGI/vmF1pIhmQXh/N8lBx8z+MRHbI3I5mtPwZhU/26DLGiKBnmJn2a 3IBGuGNV62vltGOBMHHllQGk9flIqrzeEMu7efHEtcItwTOEhfAFTwocdjHifEfkzfJt TlURZOr2dIYWDkLuAfV96N9YcTV/D8mPrR8Ga/OKCZAb4EHluPC7n1lWliT+G/ae5hRE jhyg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:content-disposition:mime-version :references:message-id:subject:cc:to:from:date:dkim-signature; bh=+TyaprsFFpe4D2IdPtCe/vGt+ZyBDLNGMTqOEUV0Y0Y=; b=GysIMCE+VOMgPI1DaLZTZJF6Or0UgCG9qQxxHqaVleAZWkuojyGJpjywEXN765zWa6 O+fMK8t72Z4Nj2l3YsHLvYHS2oKx8rMU6OQf6I8eK04/JwIfaUmuh+trPDtd9Zatff3m CJ0J5XN6Q6rMsL3N4n3R7h9RW3mT8slb6xmOs5pr7hoygOkcz+j2rJyVK4B7kZc+TKkg VyqKIEEk5p4we6+FFqCPK9cth9h1qZXPosadMppXB5siTde1aXxOOOswjWDBmOgV0uB3 Dg9Ls9Xebtn0N+7Uf4U/wbtvdeqhUmbAppMKR+ptzDyh0kKUbvvtt0opQFw6zGw+HyAA 1m2Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=ktIh2yT5; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id q21si846769ejz.227.2021.01.20.08.57.05; Wed, 20 Jan 2021 08:57:31 -0800 (PST) Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=ktIh2yT5; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731468AbhATQ4c (ORCPT + 99 others); Wed, 20 Jan 2021 11:56:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403975AbhATQVd (ORCPT ); Wed, 20 Jan 2021 11:21:33 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D1D2C061575; Wed, 20 Jan 2021 08:21:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+TyaprsFFpe4D2IdPtCe/vGt+ZyBDLNGMTqOEUV0Y0Y=; b=ktIh2yT5awX/xT5bRccUykitbs zgufB8WSm9bC+xgIIJPaJjx3/ouKSRW3nr/780xlRnnsuVhmezcnEKPSCnUf6NgrDm1i8C9IyVjoe 7oN5VPb5AgfWo7DAV0yXTMSXo83+Chdgpq5voEK9+OvpiytpbBq4cDbpWzYwyPIIfrh8NPIRtcasX IdwcjrCl/q/UWPa2RP/B/Z5UOv0F/Uz7DvSTBayM8ImJyTMLoL/46+7yxjhhEIamoJqbq6PL3l4EE DSyKwogLbgvVPII5ePApUKii8KrZcUepI/RCyxl9cvXpGs0Dvc/qunL0M5/Yo9X99iONsZNQCHSdh QMoIJrwA==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l2GDB-00FuBN-2r; Wed, 20 Jan 2021 16:20:12 +0000 Date: Wed, 20 Jan 2021 16:20:01 +0000 From: Christoph Hellwig To: Jan Kara Cc: linux-fsdevel@vger.kernel.org, Matthew Wilcox , linux-ext4@vger.kernel.org Subject: Re: [PATCH 2/3] mm: Provide address_space operation for filling pages for read Message-ID: <20210120162001.GB3790454@infradead.org> References: <20210120160611.26853-1-jack@suse.cz> <20210120160611.26853-3-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210120160611.26853-3-jack@suse.cz> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed, Jan 20, 2021 at 05:06:10PM +0100, Jan Kara wrote: > Provide an address_space operation for filling pages needed for read > into page cache. Filesystems can use this operation to seriealize > page cache filling with e.g. hole punching properly. Besides the impending rewrite of the area - having another indirection here is just horrible for performance. If we want locking in this area it should be in core code and common for multiple file systems.