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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_MUTT 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 AA588C10F03 for ; Thu, 28 Mar 2019 15:42:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AE0521773 for ; Thu, 28 Mar 2019 15:42:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="kVhyHmdo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727685AbfC1PmK (ORCPT ); Thu, 28 Mar 2019 11:42:10 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:46046 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727505AbfC1PmK (ORCPT ); Thu, 28 Mar 2019 11:42:10 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x2SFY1NN120240; Thu, 28 Mar 2019 15:41:32 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=cD6ZuC2MiZIjCszkqFz1Ts2OWaa9iNF7lGJozFeeQQI=; b=kVhyHmdoH99Ietqxs+wIw0WSiYAZnJAzsPEbkHCLP7gIR2vlUXj5iTTtDaZpx7n+IUxT CUB4S9pFqyREeJ09rDbotv6kTGfnAOud2QEeAa0357dvq9oC5Tr++MXmya4sECqkd5oL 6g6f4gcjRQeEQtZlUQI1zocV+OezfAI+uyj+7pydscjaT5+W1I55zEFdruAdRERybYRM ExrxmUrNylaIVj2MrYrRybz6PFlViaOEf+USrNbyvWDayDtlvphelKmJ8wgtFFmgVqZe dyYt3Bmsh4zHEybE1A9PfaTIUqajCfJLjazswxl1/QWE+QV0c/O3m9HjP6swxlHej+eF 5w== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by aserp2130.oracle.com with ESMTP id 2re6g17f3s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 28 Mar 2019 15:41:32 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x2SFfQQo008664 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 28 Mar 2019 15:41:27 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x2SFfQuh027485; Thu, 28 Mar 2019 15:41:26 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 28 Mar 2019 08:41:26 -0700 Date: Thu, 28 Mar 2019 08:41:25 -0700 From: "Darrick J. Wong" To: Goldwyn Rodrigues Cc: linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Goldwyn Rodrigues Subject: Re: [PATCH 08/15] dax: add dax_iomap_cow to copy a mmap page before writing Message-ID: <20190328154125.GE1172@magnolia> References: <20190326190301.32365-1-rgoldwyn@suse.de> <20190326190301.32365-9-rgoldwyn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190326190301.32365-9-rgoldwyn@suse.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9209 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903280105 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Mar 26, 2019 at 02:02:54PM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues > > dax_iomap_cow copies a page before presenting for mmap. > > Signed-off-by: Goldwyn Rodrigues > --- > fs/dax.c | 33 ++++++++++++++++++++++++++++++++- > 1 file changed, 32 insertions(+), 1 deletion(-) > > diff --git a/fs/dax.c b/fs/dax.c > index e254535dd830..21ee3df6f02c 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1269,6 +1269,33 @@ static bool dax_fault_is_synchronous(unsigned long flags, > && (iomap->flags & IOMAP_F_DIRTY); > } > > +static int dax_iomap_cow(struct iomap *iomap, loff_t pos, pfn_t *pfn) > +{ > + void *daddr; > + pgoff_t pgoff; > + long rc; > + int id; > + sector_t sector; > + > + pos = round_down(pos, PAGE_SIZE); > + > + sector = round_down(iomap->addr + iomap->offset - pos, PAGE_SIZE) >> 9; > + rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff); > + if (rc) > + return rc; > + > + id = dax_read_lock(); > + rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &daddr, pfn); > + if (rc < 0) > + goto out; > + > + dax_to_dax_copy(iomap, pos, daddr, PAGE_SIZE); > + > +out: > + dax_read_unlock(id); > + return rc; > +} > + > static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > int *iomap_errp, const struct iomap_ops *ops) > { > @@ -1372,7 +1399,11 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); > major = VM_FAULT_MAJOR; > } > - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); > + > + if (iomap.flags & IOMAP_F_COW) > + error = dax_iomap_cow(&iomap, pos, &pfn); Why wouldn't dax_iomap_cow also apply to dax_iomap_pmd_fault? --D > + else > + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); > if (error < 0) > goto error_finish_iomap; > > -- > 2.16.4 >