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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 3A566C43381 for ; Sat, 23 Feb 2019 21:32:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06FC220661 for ; Sat, 23 Feb 2019 21:32:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550957567; bh=6eov4kD3vEgAtUcH2nAG6ju6g09mVa6nepjFrOjBlrM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2h02+Bm+RaAvIdAuN87eWRJk1+zMm4hr4O3asoA7K2uRqJP+c8Z6ieTPzCEqxIooF iLbVWSnZlWBLejytAcrBv++yIbK8wPj9vyaiciLJzoJo6PSjrNX570gtKVbQeTph/i DCURPKIpd63xLUBgjO7VyRX9aoU8Ee7V/PRKQcl4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728244AbfBWVFQ (ORCPT ); Sat, 23 Feb 2019 16:05:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:40386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728248AbfBWVFP (ORCPT ); Sat, 23 Feb 2019 16:05:15 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D88B920675; Sat, 23 Feb 2019 21:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550955914; bh=6eov4kD3vEgAtUcH2nAG6ju6g09mVa6nepjFrOjBlrM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=och63sHwolKqKb2Yfb2MaatsP3LzbM3cFXoNTwJRc7VkA3xfNVyqg3PKL6SP2DylO dm63oqborrmqdwiKfrdGVVs91Uz4sEVb0Io0ty7KEjgyYOvzcSbXAvOQixcJnYgfq0 YJBiIlY64IB8n5frWnT+nxyZRaDhnD0StifLhvXc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Piotr Jaroszynski , Christoph Hellwig , "Darrick J . Wong" , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.20 29/72] iomap: get/put the page in iomap_page_create/release() Date: Sat, 23 Feb 2019 16:03:39 -0500 Message-Id: <20190223210422.199966-29-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190223210422.199966-1-sashal@kernel.org> References: <20190223210422.199966-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Piotr Jaroszynski [ Upstream commit 8e47a457321ca1a74ad194ab5dcbca764bc70731 ] migrate_page_move_mapping() expects pages with private data set to have a page_count elevated by 1. This is what used to happen for xfs through the buffer_heads code before the switch to iomap in commit 82cb14175e7d ("xfs: add support for sub-pagesize writeback without buffer_heads"). Not having the count elevated causes move_pages() to fail on memory mapped files coming from xfs. Make iomap compatible with the migrate_page_move_mapping() assumption by elevating the page count as part of iomap_page_create() and lowering it in iomap_page_release(). It causes the move_pages() syscall to misbehave on memory mapped files from xfs. It does not not move any pages, which I suppose is "just" a perf issue, but it also ends up returning a positive number which is out of spec for the syscall. Talking to Michal Hocko, it sounds like returning positive numbers might be a necessary update to move_pages() anyway though. Fixes: 82cb14175e7d ("xfs: add support for sub-pagesize writeback without buffer_heads") Signed-off-by: Piotr Jaroszynski [hch: actually get/put the page iomap_migrate_page() to make it work properly] Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Sasha Levin --- fs/iomap.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/iomap.c b/fs/iomap.c index ce837d962d473..7793e9e42ad57 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -116,6 +116,12 @@ iomap_page_create(struct inode *inode, struct page *page) atomic_set(&iop->read_count, 0); atomic_set(&iop->write_count, 0); bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE); + + /* + * migrate_page_move_mapping() assumes that pages with private data have + * their count elevated by 1. + */ + get_page(page); set_page_private(page, (unsigned long)iop); SetPagePrivate(page); return iop; @@ -132,6 +138,7 @@ iomap_page_release(struct page *page) WARN_ON_ONCE(atomic_read(&iop->write_count)); ClearPagePrivate(page); set_page_private(page, 0); + put_page(page); kfree(iop); } @@ -569,8 +576,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage, if (page_has_private(page)) { ClearPagePrivate(page); + get_page(newpage); set_page_private(newpage, page_private(page)); set_page_private(page, 0); + put_page(page); SetPagePrivate(newpage); } -- 2.19.1