From patchwork Mon Mar 21 13:22:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 8632781 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 A70459FD4C for ; Mon, 21 Mar 2016 13:22:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C05AD202F8 for ; Mon, 21 Mar 2016 13:22:37 +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 5D3B82034B for ; Mon, 21 Mar 2016 13:22:35 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 1FE771A1FD0; Mon, 21 Mar 2016 06:22:58 -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 347CD1A1FCD for ; Mon, 21 Mar 2016 06:22:56 -0700 (PDT) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 126AFAD30; Mon, 21 Mar 2016 13:22:31 +0000 (UTC) Received: by quack.suse.cz (Postfix, from userid 1000) id BA6DC82523; Mon, 21 Mar 2016 14:22:58 +0100 (CET) From: Jan Kara To: linux-fsdevel@vger.kernel.org Subject: [PATCH 05/10] dax: Allow DAX code to replace exceptional entries Date: Mon, 21 Mar 2016 14:22:50 +0100 Message-Id: <1458566575-28063-6-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1458566575-28063-1-git-send-email-jack@suse.cz> References: <1458566575-28063-1-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: Jan Kara , linux-nvdimm@lists.01.org, NeilBrown , "Wilcox, Matthew R" MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Spam-Status: No, score=-1.9 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. Signed-off-by: Jan Kara --- include/linux/dax.h | 6 ++++++ mm/filemap.c | 18 +++++++++++------- 2 files changed, 17 insertions(+), 7 deletions(-) diff --git a/include/linux/dax.h b/include/linux/dax.h index 7c45ac7ea1d1..4b63923e1f8d 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -3,8 +3,14 @@ #include #include +#include #include +/* + * Since exceptional entries do not use indirect bit, we reuse it as a lock bit + */ +#define DAX_ENTRY_LOCK RADIX_TREE_INDIRECT_PTR + ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t, get_block_t, dio_iodone_t, int flags); int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size); diff --git a/mm/filemap.c b/mm/filemap.c index 7c00f105845e..fbebedaf719e 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -597,14 +597,18 @@ 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 | + DAX_ENTRY_LOCK)); + } } radix_tree_replace_slot(slot, page); mapping->nrpages++;