From patchwork Thu May 12 16:29:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9084151 Return-Path: X-Original-To: patchwork-linux-nvdimm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7391B9F372 for ; Thu, 12 May 2016 16:29:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EF009201F2 for ; Thu, 12 May 2016 16:29:36 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0F22B2024C for ; Thu, 12 May 2016 16:29:36 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 4F9881A1F88; Thu, 12 May 2016 09:29:35 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 1F1111A1F66 for ; Thu, 12 May 2016 09:29:34 -0700 (PDT) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 856F2AC95; Thu, 12 May 2016 16:29:30 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 7148A1E0A11; Thu, 12 May 2016 18:29:28 +0200 (CEST) From: Jan Kara To: linux-nvdimm@lists.01.org Subject: [PATCH 4/7] dax: Allow DAX code to replace exceptional entries Date: Thu, 12 May 2016 18:29:17 +0200 Message-Id: <1463070560-1979-5-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1463070560-1979-1-git-send-email-jack@suse.cz> References: <1463070560-1979-1-git-send-email-jack@suse.cz> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ted Tso , linux-fsdevel@vger.kernel.org, Jan Kara , linux-ext4@vger.kernel.org MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently we forbid page_cache_tree_insert() to replace exceptional radix tree entries for DAX inodes. However to make DAX faults race free we will lock radix tree entries and when hole is created, we need to replace such locked radix tree entry with a hole page. So modify page_cache_tree_insert() to allow that. Reviewed-by: Ross Zwisler Signed-off-by: Jan Kara --- include/linux/dax.h | 1 + mm/filemap.c | 21 ++++++++++++++------- 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/include/linux/dax.h b/include/linux/dax.h index d0883daa66d9..8558d3770a30 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -3,6 +3,7 @@ #include #include +#include #include /* We use lowest available exceptional entry bit for locking */ diff --git a/mm/filemap.c b/mm/filemap.c index f2479af09da9..dfe55c2cfb34 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -597,14 +597,21 @@ static int page_cache_tree_insert(struct address_space *mapping, if (!radix_tree_exceptional_entry(p)) return -EEXIST; - if (WARN_ON(dax_mapping(mapping))) - return -EINVAL; - - if (shadowp) - *shadowp = p; mapping->nrexceptional--; - if (node) - workingset_node_shadows_dec(node); + if (!dax_mapping(mapping)) { + if (shadowp) + *shadowp = p; + if (node) + workingset_node_shadows_dec(node); + } else { + /* DAX can replace empty locked entry with a hole */ + WARN_ON_ONCE(p != + (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | + RADIX_DAX_ENTRY_LOCK)); + /* DAX accounts exceptional entries as normal pages */ + if (node) + workingset_node_pages_dec(node); + } } radix_tree_replace_slot(slot, page); mapping->nrpages++;