From patchwork Thu Feb 2 20:44:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13126719 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26C80C61DA4 for ; Thu, 2 Feb 2023 20:44:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232955AbjBBUoj (ORCPT ); Thu, 2 Feb 2023 15:44:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232067AbjBBUof (ORCPT ); Thu, 2 Feb 2023 15:44:35 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C74C48A58; Thu, 2 Feb 2023 12:44:33 -0800 (PST) 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=CHTViCFku/KBgg0p6DZbUUb80eMrbMHO+BwTMmLL/c8=; b=Cnpe1akXRcTjrbOFxM+9HrW+ur d1lfcvyzmUOAlYVR9x6xYmCbrq53KnUEe+yqtSAHOPbH7OHm0rewQg2RMYzAmtBFcYZE4oSeqLxMi eCHHJ8dFrq4kz9d/JcMQzW5XpXnfBUje4e46WGl4WZgLZJBy7/sDkudm3R/iXLIpz5Vh7F5wllJ7I OUkIXT5U0OkITUYHT6Dd+ODvKs5q3qcDfvn3fcX5d53emCWIimY8ED0Y5esijwiT7AN7seZkhU+G+ eFufWstFTegm87OA4SkZuEQOD6F1ZgjDbt9nNJNndVfqGOf533nK3ibsN/iH0hY3EkdfhgfQTwKHm GPQu7rFA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pNgRa-00Di7O-Ue; Thu, 02 Feb 2023 20:44:31 +0000 From: "Matthew Wilcox (Oracle)" To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-afs@lists.infradead.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-mm@kvack.org, Hugh Dickins , linux-kernel@vger.kernel.org, fstests@vger.kernel.org Subject: [PATCH 2/5] ext4: Zero bytes after 'oldsize' if we're expanding the file Date: Thu, 2 Feb 2023 20:44:24 +0000 Message-Id: <20230202204428.3267832-3-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230202204428.3267832-1-willy@infradead.org> References: <20230202204428.3267832-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org POSIX requires that "If the file size is increased, the extended area shall appear as if it were zero-filled". It is possible to use mmap to write past EOF and that data will become visible instead of zeroes. Signed-off-by: Matthew Wilcox (Oracle) --- fs/ext4/inode.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9d9f414f99fe..14e3fa99f733 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5604,6 +5604,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, if (!shrink) { pagecache_isize_extended(inode, oldsize, inode->i_size); + truncate_pagecache(inode, oldsize); } else if (ext4_should_journal_data(inode)) { ext4_wait_for_tail_page_commit(inode); }