From patchwork Thu Apr 8 12:51:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12190977 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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C1E61C433B4 for ; Thu, 8 Apr 2021 12:51:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ACF261131 for ; Thu, 8 Apr 2021 12:51:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231308AbhDHMv1 (ORCPT ); Thu, 8 Apr 2021 08:51:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41902 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230467AbhDHMv1 (ORCPT ); Thu, 8 Apr 2021 08:51:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617886276; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zKMmQQAIPSzXF3Uyz4vJn25BHWiB2y9JZrHeB/ymjfo=; b=ennNN1TDQuEzLEKadyqxc+5JoKXTW1u6ypd0zwXbxeknaEswzikpybEcKlDuXjlhrnoz0Z v+CZrW+SDJ8GYJ3FSgA9zd+cXV1zSp+ijPT5toj9yA6g6mmUW3XVa6xwtO5UPKmPDoi+S2 /4ppxbCrhV0/mjtC+SeYDtn/VpbYrXs= 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-229-8M_oQuwtNpu6ut2GboIXvA-1; Thu, 08 Apr 2021 08:51:14 -0400 X-MC-Unique: 8M_oQuwtNpu6ut2GboIXvA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5BC24107ACE8; Thu, 8 Apr 2021 12:51:13 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-115-201.rdu2.redhat.com [10.10.115.201]) by smtp.corp.redhat.com (Postfix) with ESMTP id 96A9960864; Thu, 8 Apr 2021 12:51:12 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20210407201857.3582797-4-willy@infradead.org> References: <20210407201857.3582797-4-willy@infradead.org> <20210407201857.3582797-1-willy@infradead.org> To: "Matthew Wilcox (Oracle)" , jlayton@kernel.org Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org Subject: [PATCH] mm, netfs: Fix readahead bits MIME-Version: 1.0 Content-ID: <1234932.1617886271.1@warthog.procyon.org.uk> Date: Thu, 08 Apr 2021 13:51:11 +0100 Message-ID: <1234933.1617886271@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Willy, Jeff, I think we need the attached change to readahead_expand() to fix the oops seen when it tries to dereference ractl->ra when called indirectly from netfs_write_begin(). netfs_write_begin() should also be using DEFINE_READAHEAD() rather than manually initialising the ractl variable so that Willy can find it;-). David --- commit 9c0931285131c3b65ab4b58b614c30c7feb1dbd4 Author: David Howells Date: Thu Apr 8 13:39:54 2021 +0100 netfs: readahead fixes diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 762a15350242..1d3b50c5db6d 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -1065,12 +1065,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, loff_t size; int ret; - struct readahead_control ractl = { - .file = file, - .mapping = mapping, - ._index = index, - ._nr_pages = 0, - }; + DEFINE_READAHEAD(ractl, file, NULL, mapping, index); retry: page = grab_cache_page_write_begin(mapping, index, 0); diff --git a/mm/readahead.c b/mm/readahead.c index 65215c48f25c..f02dbebf1cef 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -706,8 +706,10 @@ void readahead_expand(struct readahead_control *ractl, return; } ractl->_nr_pages++; - ra->size++; - ra->async_size++; + if (ra) { + ra->size++; + ra->async_size++; + } } } EXPORT_SYMBOL(readahead_expand);