From patchwork Sat Sep 5 12:13:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 11759043 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 1B0A5618 for ; Sat, 5 Sep 2020 12:13:16 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DDF452078D for ; Sat, 5 Sep 2020 12:13:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="g4nUQhhl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDF452078D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id B40BB13DB5424; Sat, 5 Sep 2020 05:13:15 -0700 (PDT) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=207.211.31.120; helo=us-smtp-1.mimecast.com; envelope-from=mpatocka@redhat.com; receiver= Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 5C48F13DAD433 for ; Sat, 5 Sep 2020 05:13:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599307992; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=WHiq5fa/IzvIT3iZbseq6dJ4UmL8j1xtV2j4zAaXmDU=; b=g4nUQhhlipkd6GTBXMrFYsJuFmhqLyYFSrmtsDsfcRVNT16bEESV73OJx8cvwkdC5JP0uD JIyekixPtYbKkvwEZS3B8kfdse61i9Y3KGudTGky5oH74PMhFmQg3yc4/esKI2k4RbKHTf Chfnmu+qd8oGOOQXrqwZTddJrquivsQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-147-10FS3LDTPYaWtHPHRukgAg-1; Sat, 05 Sep 2020 08:13:08 -0400 X-MC-Unique: 10FS3LDTPYaWtHPHRukgAg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B2DC31005E74; Sat, 5 Sep 2020 12:13:05 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C8F6F7ED7D; Sat, 5 Sep 2020 12:13:02 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 085CD2bl012814; Sat, 5 Sep 2020 08:13:02 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 085CD2uR012810; Sat, 5 Sep 2020 08:13:02 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Sat, 5 Sep 2020 08:13:02 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Linus Torvalds , Jan Kara , "Darrick J. Wong" , Dave Chinner Subject: [PATCH 2/2] xfs: don't update mtime on COW faults In-Reply-To: Message-ID: References: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Message-ID-Hash: 4W27WZ3HOREMERBXZ6N2XE3BNFKV7ITO X-Message-ID-Hash: 4W27WZ3HOREMERBXZ6N2XE3BNFKV7ITO X-MailFrom: mpatocka@redhat.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: Jann Horn , Christoph Hellwig , Oleg Nesterov , Kirill Shutemov , Theodore Ts'o , Andrea Arcangeli , Matthew Wilcox , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: 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: Mikulas Patocka --- fs/xfs/xfs_file.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) Index: linux-2.6/fs/xfs/xfs_file.c =================================================================== --- linux-2.6.orig/fs/xfs/xfs_file.c 2020-09-05 10:01:42.000000000 +0200 +++ linux-2.6/fs/xfs/xfs_file.c 2020-09-05 13:59:12.000000000 +0200 @@ -1223,6 +1223,13 @@ __xfs_filemap_fault( return ret; } +static 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) @@ -1230,7 +1237,7 @@ 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 @@ -1243,7 +1250,7 @@ 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