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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 8AEEEC2D0A3 for ; Mon, 9 Nov 2020 13:29:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 323D22076E for ; Mon, 9 Nov 2020 13:29:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="eUYnzm+r" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732476AbgKIN3q (ORCPT ); Mon, 9 Nov 2020 08:29:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730134AbgKIN3p (ORCPT ); Mon, 9 Nov 2020 08:29:45 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AFEE4C0613CF for ; Mon, 9 Nov 2020 05:29:44 -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=NS2a1pD9Wqpg1Yiz1D4KYgVHI/WjaHvVakpdehgr1oE=; b=eUYnzm+rzLOYf+Fj8s9E1XdsHU 2pArMGi8q6wCvN81EU0SK1kL/B5qnbL9yXX5xqrCX2P9lUuyslAQLnWrpMJc0139iXTMdaWQbebte T/GErrfnX9guPpaMBKWHfYVt5pnxGDqhHhqnkTUdWqNWN4E5hKZbliOV8v4i0Kt7fo9NSj7BisFLq tBO0FqDioJ0MAVuVP7EZqsj2WqiIt18EnLnhn/xwSMyglynUIgRrwGOo/MmuNC5RG+5zSCCkMsYNB Qj5O6ZHdcw/mdOsEe6vkNbJo0Ilwu6ADUQme98d/RLBYiad5EQRzC3u3nhWWtyavyX5cjbzb9Ob+c Tun+kldA==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kc7Es-0005ty-15; Mon, 09 Nov 2020 13:29:42 +0000 Date: Mon, 9 Nov 2020 13:29:41 +0000 From: Matthew Wilcox To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, kent.overstreet@gmail.com Subject: Re: [PATCH v2 11/18] mm/filemap: Convert filemap_update_page to return an errno Message-ID: <20201109132941.GA17076@casper.infradead.org> References: <20201104204219.23810-1-willy@infradead.org> <20201104204219.23810-12-willy@infradead.org> <20201106081420.GF31585@lst.de> <20201106083746.GA720@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106083746.GA720@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Nov 06, 2020 at 09:37:46AM +0100, Christoph Hellwig wrote: > > - error = AOP_TRUNCATED_PAGE; > - if (!page->mapping) > - goto unlock; > - if (filemap_range_uptodate(iocb, mapping, iter, page)) { > + if (!page->mapping) { > unlock_page(page); > - return 0; > + put_page(page); > + return AOP_TRUNCATED_PAGE; > } > > - error = -EAGAIN; > - if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) > - goto unlock; > + if (!filemap_range_uptodate(iocb, mapping, iter, page)) { > + error = -EAGAIN; > + if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) > + goto unlock; > + return filemap_read_page(iocb->ki_filp, mapping, page); > + } > > - error = filemap_read_page(iocb->ki_filp, mapping, page); > - if (error) > - goto error; > - return 0; > unlock: > unlock_page(page); > -error: > - put_page(page); > return error; > } It works out to be a little more complicated than that because filemap_read_page() can also return AOP_TRUNCATED_PAGE. Here's what I currently have: if (!page->mapping) goto truncated; error = 0; if (filemap_range_uptodate(iocb, mapping, iter, page)) goto unlock; error = -EAGAIN; if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) goto unlock; error = filemap_read_page(iocb->ki_filp, mapping, page); if (error == AOP_TRUNCATED_PAGE) put_page(page); return error; truncated: error = AOP_TRUNCATED_PAGE; put_page(page); unlock: unlock_page(page); return error; }