From patchwork Tue Sep 8 15:25:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 310082 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=ham 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 B23D2C43461 for ; Tue, 8 Sep 2020 16:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74567206B5 for ; Tue, 8 Sep 2020 16:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599581440; bh=MEmvLFwTluSLMx2cM/SWoItoFmupNuwGFBxSHz1bvcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Blu0K1iZN5KToo5Zem6sh1PpraziJW/IxArjUY8Z0ytnQShzt2EbctHuaJQgv2MoC ktcNVRGnrcUN6b0skpemwyG9V+ZP71Nd9gV2W/r8fEy0zjAzQQqm3C/ZwhVp734/vJ JLGR/XjXwsYcH+oIB+3PEaJK4q8tfja6Quk5+EG0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731439AbgIHQKd (ORCPT ); Tue, 8 Sep 2020 12:10:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:56660 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731401AbgIHQKZ (ORCPT ); Tue, 8 Sep 2020 12:10:25 -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 5CB4924695; Tue, 8 Sep 2020 15:50:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580228; bh=MEmvLFwTluSLMx2cM/SWoItoFmupNuwGFBxSHz1bvcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Buop4rt4A59inIQhHF9mALkzk+TYZ+I7Wsssq9oQywnPiK3htT5WptPVHE3Zsnb8Y DaE1jYNgbFGtSggqH7kgymFwBbHId8OVfaECZ/WPcZbl11NnmIiMSw5OwskHdlcZ1O IthfGTyjTrRcmGqKWPjQ0xJB1fUwh4lwPNs1tcGE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Linus Torvalds Subject: [PATCH 4.19 52/88] ext2: dont update mtime on COW faults Date: Tue, 8 Sep 2020 17:25:53 +0200 Message-Id: <20200908152223.727402691@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152221.082184905@linuxfoundation.org> References: <20200908152221.082184905@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mikulas Patocka commit 1ef6ea0efe8e68d0299dad44c39dc6ad9e5d1f39 upstream. When running in a dax mode, if the user maps a page with MAP_PRIVATE and PROT_WRITE, the ext2 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 ext2 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/ext2/file.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -93,8 +93,10 @@ static vm_fault_t ext2_dax_fault(struct struct inode *inode = file_inode(vmf->vma->vm_file); struct ext2_inode_info *ei = EXT2_I(inode); vm_fault_t ret; + bool write = (vmf->flags & FAULT_FLAG_WRITE) && + (vmf->vma->vm_flags & VM_SHARED); - if (vmf->flags & FAULT_FLAG_WRITE) { + if (write) { sb_start_pagefault(inode->i_sb); file_update_time(vmf->vma->vm_file); } @@ -103,7 +105,7 @@ static vm_fault_t ext2_dax_fault(struct ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops); up_read(&ei->dax_sem); - if (vmf->flags & FAULT_FLAG_WRITE) + if (write) sb_end_pagefault(inode->i_sb); return ret; }