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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 04752C433E2 for ; Tue, 8 Sep 2020 19:10:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C240120708 for ; Tue, 8 Sep 2020 19:10:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599592243; bh=OHJAv06qZoq3OhRqsI02z1f04r0K+39Op1CU4gZCoO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Di/rlmUblTsCq7aLuAceaSHJaIoWCIDRdm6A9pkX0HnZnnYz9tWhv7cyieL3U4y32 aSHhB1tcUEQhYflvcZK+EBvC5kjArYb8Ihq3+2c9zcY6iFDZouvEQt20zzRbIGWbbk zPAjOUFOZrcUdAQcEl/Godw+j7jJuSH/DEp3PjmA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731275AbgIHTKU (ORCPT ); Tue, 8 Sep 2020 15:10:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:53446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731239AbgIHQFh (ORCPT ); Tue, 8 Sep 2020 12:05:37 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5665522A83; Tue, 8 Sep 2020 15:46:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599579973; bh=OHJAv06qZoq3OhRqsI02z1f04r0K+39Op1CU4gZCoO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=du720iQzOk4zYlbLMRRbmxbxc+IZdu0XI5LmB4asZhgoodOirqqw3Bf0nSSrsTxtO uGaKMFUbb5nQnAt4zk80dZQ6oRACG0K5oBapAlgZIg/Ev5QBxqZ6RJl3EOUI8N3J2e bTpEbJ7I9gKpRJirq3Atfy0hRUT6ZFWe9kVqMqMM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Linus Torvalds Subject: [PATCH 5.4 079/129] xfs: dont update mtime on COW faults Date: Tue, 8 Sep 2020 17:25:20 +0200 Message-Id: <20200908152233.646658986@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152229.689878733@linuxfoundation.org> References: <20200908152229.689878733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mikulas Patocka commit b17164e258e3888d376a7434415013175d637377 upstream. When running in a dax mode, if the user maps a page with MAP_PRIVATE and PROT_WRITE, the xfs filesystem would incorrectly update ctime and mtime when the user hits a COW fault. This breaks building of the Linux kernel. How to reproduce: 1. extract the Linux kernel tree on dax-mounted xfs filesystem 2. run make clean 3. run make -j12 4. run make -j12 at step 4, make would incorrectly rebuild the whole kernel (although it was already built in step 3). The reason for the breakage is that almost all object files depend on objtool. When we run objtool, it takes COW page fault on its .data section, and these faults will incorrectly update the timestamp of the objtool binary. The updated timestamp causes make to rebuild the whole tree. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_file.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1172,6 +1172,14 @@ __xfs_filemap_fault( return ret; } +static inline bool +xfs_is_write_fault( + struct vm_fault *vmf) +{ + return (vmf->flags & FAULT_FLAG_WRITE) && + (vmf->vma->vm_flags & VM_SHARED); +} + static vm_fault_t xfs_filemap_fault( struct vm_fault *vmf) @@ -1179,7 +1187,7 @@ xfs_filemap_fault( /* DAX can shortcut the normal fault path on write faults! */ return __xfs_filemap_fault(vmf, PE_SIZE_PTE, IS_DAX(file_inode(vmf->vma->vm_file)) && - (vmf->flags & FAULT_FLAG_WRITE)); + xfs_is_write_fault(vmf)); } static vm_fault_t @@ -1192,7 +1200,7 @@ xfs_filemap_huge_fault( /* DAX can shortcut the normal fault path on write faults! */ return __xfs_filemap_fault(vmf, pe_size, - (vmf->flags & FAULT_FLAG_WRITE)); + xfs_is_write_fault(vmf)); } static vm_fault_t