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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 9C71EC43617 for ; Fri, 23 Apr 2021 17:30:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AAB261404 for ; Fri, 23 Apr 2021 17:30:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243465AbhDWRbC (ORCPT ); Fri, 23 Apr 2021 13:31:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:43728 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243429AbhDWRa7 (ORCPT ); Fri, 23 Apr 2021 13:30:59 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5EAE9B1D6; Fri, 23 Apr 2021 17:30:19 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id C3FC11F2C54; Fri, 23 Apr 2021 19:30:18 +0200 (CEST) From: Jan Kara To: Cc: Christoph Hellwig , Amir Goldstein , Dave Chinner , Ted Tso , Jan Kara , Steve French , linux-cifs@vger.kernel.org Subject: [PATCH 12/12] cifs: Fix race between hole punch and page fault Date: Fri, 23 Apr 2021 19:29:41 +0200 Message-Id: <20210423173018.23133-12-jack@suse.cz> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210423171010.12-1-jack@suse.cz> References: <20210423171010.12-1-jack@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Cifs has a following race between hole punching and page fault: CPU1 CPU2 smb3_fallocate() smb3_punch_hole() truncate_pagecache_range() filemap_fault() - loads old data into the page cache SMB2_ioctl(..., FSCTL_SET_ZERO_DATA, ...) And now we have stale data in the page cache. Fix the problem by locking out faults (as well as reads) using mapping->invalidate_lock while hole punch is running. CC: Steve French CC: linux-cifs@vger.kernel.org Signed-off-by: Jan Kara --- fs/cifs/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index f703204fb185..18231f9bc336 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3543,6 +3543,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon, return rc; } + down_write(&inode->i_mapping->invalidate_lock); /* * We implement the punch hole through ioctl, so we need remove the page * caches first, otherwise the data may be inconsistent with the server. @@ -3560,6 +3561,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon, sizeof(struct file_zero_data_information), CIFSMaxBufSize, NULL, NULL); free_xid(xid); + up_write(&inode->i_mapping->invalidate_lock); return rc; } -- 2.26.2