From patchwork Mon Aug 24 15:16:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 11733507 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AA5EB138A for ; Mon, 24 Aug 2020 15:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 921F420866 for ; Mon, 24 Aug 2020 15:26:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="udgs60rQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727903AbgHXPZg (ORCPT ); Mon, 24 Aug 2020 11:25:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727068AbgHXPRN (ORCPT ); Mon, 24 Aug 2020 11:17:13 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7526EC061575; Mon, 24 Aug 2020 08:17:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=EnhOr651fYG//wVSSI2lABo+UhZFOxuqGW2PFxxTzF8=; b=udgs60rQFoUDneH6c+cOnxYloe oP2a2dWBv33jQrN/PrdqpCym621ma9scUuR8om7YiIO8QqKMEr8jXHJDDXf4A+j9dOcecTa7CAJRY qTzNmzkVcIq/ORNZaKLOQk9wNnfLBllsEJX59nQ/7/4FR1f/LzW5IkcJ3qpJ/k+nKWwUKg7eFH+ko EFxsIJFDg5er5xfChA9HgBSodRIVTTwUS7u9GLfQVIry20YBBhVxKNurwfEYpumD60GgPcdmOt/08 rllwFwgX+ekgdSz1i3SPpC/nEbn+G09/J3Ew4w+qnOE0kUEvCLwyV6hBgXD5Dsfc3DMg8gyUJIPJN HcO2EHtg==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAEDW-0004Ca-QM; Mon, 24 Aug 2020 15:17:02 +0000 From: "Matthew Wilcox (Oracle)" To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , "Darrick J . Wong" , linux-block@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 03/11] mm: Zero the head page, not the tail page Date: Mon, 24 Aug 2020 16:16:52 +0100 Message-Id: <20200824151700.16097-4-willy@infradead.org> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200824151700.16097-1-willy@infradead.org> References: <20200824151700.16097-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Pass the head page to zero_user_segment(), not the tail page, and adjust the byte offsets appropriately. Signed-off-by: Matthew Wilcox (Oracle) --- mm/shmem.c | 7 +++++++ mm/truncate.c | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index 271548ca20f3..77982149b437 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -958,11 +958,18 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, struct page *page = NULL; shmem_getpage(inode, start - 1, &page, SGP_READ); if (page) { + struct page *head = thp_head(page); unsigned int top = PAGE_SIZE; if (start > end) { top = partial_end; partial_end = 0; } + if (head != page) { + unsigned int diff = start - 1 - head->index; + partial_start += diff << PAGE_SHIFT; + top += diff << PAGE_SHIFT; + page = head; + } zero_user_segment(page, partial_start, top); set_page_dirty(page); unlock_page(page); diff --git a/mm/truncate.c b/mm/truncate.c index dd9ebc1da356..152974888124 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -374,12 +374,19 @@ void truncate_inode_pages_range(struct address_space *mapping, if (partial_start) { struct page *page = find_lock_page(mapping, start - 1); if (page) { + struct page *head = thp_head(page); unsigned int top = PAGE_SIZE; if (start > end) { /* Truncation within a single page */ top = partial_end; partial_end = 0; } + if (head != page) { + unsigned int diff = start - 1 - head->index; + partial_start += diff << PAGE_SHIFT; + top += diff << PAGE_SHIFT; + page = head; + } wait_on_page_writeback(page); zero_user_segment(page, partial_start, top); cleancache_invalidate_page(mapping, page);