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 7C39EC43464 for ; Thu, 17 Sep 2020 22:03:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7592208DB for ; Thu, 17 Sep 2020 22:03:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ICDUnkL7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726255AbgIQWDK (ORCPT ); Thu, 17 Sep 2020 18:03:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725900AbgIQWDK (ORCPT ); Thu, 17 Sep 2020 18:03:10 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 331EEC06174A; Thu, 17 Sep 2020 15:03:10 -0700 (PDT) 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=ubJtVk08jzU3J8YPE2lJLRaYSsnYYHZKYdrpjiW6yU4=; b=ICDUnkL72CW96WATA+3jxM5vWb 6oYT1enLOn3O4Ag28G+e5sc4FqNNUy2Ikgxnpx/LhvjaiBKvrZWAbYzkaYIkc/NjzWtAUaMsW8kTk Yue6qkZhlQb9iYXfoXv9v9sKs+He0hXzIgOzvhGW01abuVdlCsLu5ep5X71lnTxbrbq9ljbXhS2jN fZS2WZ9OlwwNROzSqPlT2fhEu7ifLnDLSIWkeEha9ouk+MkogWQ6Zy5o5FAh5nDVbZ7+o9C1tZcrW sIbCrABL5nerc0GAMK3sNquTExIDELUO/f3nddMDsbHnosACnqilx6WvwEtmQbtPzdCn8oS1kPCcM eCOrz5Qw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJ1zf-0003eq-8d; Thu, 17 Sep 2020 22:03:07 +0000 Date: Thu, 17 Sep 2020 23:03:07 +0100 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org, v9fs-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, ecryptfs@vger.kernel.org, linux-um@lists.infradead.org, linux-mtd@lists.infradead.org, Richard Weinberger Subject: Re: [PATCH 01/13] mm: Add AOP_UPDATED_PAGE return value Message-ID: <20200917220307.GX5449@casper.infradead.org> References: <20200917151050.5363-1-willy@infradead.org> <20200917151050.5363-2-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200917151050.5363-2-willy@infradead.org> Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Thu, Sep 17, 2020 at 04:10:38PM +0100, Matthew Wilcox (Oracle) wrote: > +++ b/mm/filemap.c > @@ -2254,8 +2254,10 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, > * PG_error will be set again if readpage fails. > */ > ClearPageError(page); > - /* Start the actual read. The read will unlock the page. */ > + /* Start the actual read. The read may unlock the page. */ > error = mapping->a_ops->readpage(filp, page); > + if (error == AOP_UPDATED_PAGE) > + goto page_ok; > > if (unlikely(error)) { > if (error == AOP_TRUNCATED_PAGE) { If anybody wants to actually test this, this hunk is wrong. +++ b/mm/filemap.c @@ -2256,8 +2256,11 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, ClearPageError(page); /* Start the actual read. The read may unlock the page. */ error = mapping->a_ops->readpage(filp, page); - if (error == AOP_UPDATED_PAGE) + if (error == AOP_UPDATED_PAGE) { + unlock_page(page); + error = 0; goto page_ok; + } if (unlikely(error)) { if (error == AOP_TRUNCATED_PAGE) { > @@ -2619,7 +2621,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > */ > if (unlikely(!PageUptodate(page))) > goto page_not_uptodate; > - > +page_ok: > /* > * We've made it this far and we had to drop our mmap_lock, now is the > * time to return to the upper layer and have it re-find the vma and > @@ -2654,6 +2656,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > ClearPageError(page); > fpin = maybe_unlock_mmap_for_io(vmf, fpin); > error = mapping->a_ops->readpage(file, page); > + if (error == AOP_UPDATED_PAGE) > + goto page_ok; > if (!error) { > wait_on_page_locked(page); > if (!PageUptodate(page)) > @@ -2867,6 +2871,10 @@ static struct page *do_read_cache_page(struct address_space *mapping, > err = filler(data, page); > else > err = mapping->a_ops->readpage(data, page); > + if (err == AOP_UPDATED_PAGE) { > + unlock_page(page); > + goto out; > + } > > if (err < 0) { > put_page(page); > -- > 2.28.0 >