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,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED 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 2CC11C2D0A3 for ; Thu, 29 Oct 2020 21:45:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B40D420838 for ; Thu, 29 Oct 2020 21:45:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WIJnfQv+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725562AbgJ2Vpc (ORCPT ); Thu, 29 Oct 2020 17:45:32 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:32956 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725372AbgJ2Vpc (ORCPT ); Thu, 29 Oct 2020 17:45:32 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09TLTLE9143644; Thu, 29 Oct 2020 21:45:29 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-2020-01-29; bh=lVkSpCpdWLHgD8gFp7iFH+kz2DvbOKUCIkxdli4g6CA=; b=WIJnfQv+BoKwJwtXOc1CgmWes2PvstnRM1CprIGoEuXRGvGVc8YjUlwfqUDzb9fCOOPz u890OFHvZ5EYFfmfVABXtIv1ulgwaIYCBHrKY50qi4gcxeWEddjQVyCuGQhulJpfVWZ9 OZ9kMou1QpINVYL/WLTe4FRQUHrP9yq1NSSprBUGf7sDSQMQmiAC2mHRFpVuf/nKMxb5 iN3l0N1ro1ttDpsJ7waHCdejhC83F2uIEIlxnJGDs9F4Api1v2CdqK7+dWnzuT4CNQe1 WVCvjLMAUwPLq8PWDzH/8O+rpAGFH2/b8YpR0qrZlLarE9BcNfZJPYGDrF2P+o1zOEyd 2Q== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2130.oracle.com with ESMTP id 34c9sb7ccq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 29 Oct 2020 21:45:29 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09TLjR80049271; Thu, 29 Oct 2020 21:45:28 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 34cx6yyc2k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Oct 2020 21:45:28 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09TLjMXQ025568; Thu, 29 Oct 2020 21:45:23 GMT Received: from localhost (/10.159.244.77) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 29 Oct 2020 14:45:22 -0700 Date: Thu, 29 Oct 2020 14:45:21 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH v2.1 2/3] iomap: support partial page discard on writeback block mapping failure Message-ID: <20201029214521.GJ1061252@magnolia> References: <20201029132325.1663790-3-bfoster@redhat.com> <20201029163313.1766967-1-bfoster@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201029163313.1766967-1-bfoster@redhat.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9789 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 spamscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 suspectscore=1 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010290150 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9789 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 impostorscore=0 mlxlogscore=999 malwarescore=0 lowpriorityscore=0 bulkscore=0 priorityscore=1501 spamscore=0 phishscore=0 clxscore=1015 suspectscore=1 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010290149 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Oct 29, 2020 at 12:33:13PM -0400, Brian Foster wrote: > iomap writeback mapping failure only calls into ->discard_page() if > the current page has not been added to the ioend. Accordingly, the > XFS callback assumes a full page discard and invalidation. This is > problematic for sub-page block size filesystems where some portion > of a page might have been mapped successfully before a failure to > map a delalloc block occurs. ->discard_page() is not called in that > error scenario and the bio is explicitly failed by iomap via the > error return from ->prepare_ioend(). As a result, the filesystem > leaks delalloc blocks and corrupts the filesystem block counters. > > Since XFS is the only user of ->discard_page(), tweak the semantics > to invoke the callback unconditionally on mapping errors and provide > the file offset that failed to map. Update xfs_discard_page() to > discard the corresponding portion of the file and pass the range > along to iomap_invalidatepage(). The latter already properly handles > both full and sub-page scenarios by not changing any iomap or page > state on sub-page invalidations. > > Signed-off-by: Brian Foster > Reviewed-by: Christoph Hellwig Thanks for the rebase, Reviewed-by: Darrick J. Wong --D > --- > > v2.1: > - Rebased to v5.10-rc1. > > fs/iomap/buffered-io.c | 15 ++++++++------- > fs/xfs/xfs_aops.c | 14 ++++++++------ > include/linux/iomap.h | 2 +- > 3 files changed, 17 insertions(+), 14 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 8180061b9e16..e4ea1f9f94d0 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1382,14 +1382,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, > * appropriately. > */ > if (unlikely(error)) { > + /* > + * Let the filesystem know what portion of the current page > + * failed to map. If the page wasn't been added to ioend, it > + * won't be affected by I/O completion and we must unlock it > + * now. > + */ > + if (wpc->ops->discard_page) > + wpc->ops->discard_page(page, file_offset); > if (!count) { > - /* > - * If the current page hasn't been added to ioend, it > - * won't be affected by I/O completions and we must > - * discard and unlock it right here. > - */ > - if (wpc->ops->discard_page) > - wpc->ops->discard_page(page); > ClearPageUptodate(page); > unlock_page(page); > goto done; > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 55d126d4e096..5bf37afae5e9 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -527,13 +527,15 @@ xfs_prepare_ioend( > */ > static void > xfs_discard_page( > - struct page *page) > + struct page *page, > + loff_t fileoff) > { > struct inode *inode = page->mapping->host; > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > - loff_t offset = page_offset(page); > - xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset); > + unsigned int pageoff = offset_in_page(fileoff); > + xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff); > + xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); > int error; > > if (XFS_FORCED_SHUTDOWN(mp)) > @@ -541,14 +543,14 @@ xfs_discard_page( > > xfs_alert_ratelimited(mp, > "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.", > - page, ip->i_ino, offset); > + page, ip->i_ino, fileoff); > > error = xfs_bmap_punch_delalloc_range(ip, start_fsb, > - i_blocks_per_page(inode, page)); > + i_blocks_per_page(inode, page) - pageoff_fsb); > if (error && !XFS_FORCED_SHUTDOWN(mp)) > xfs_alert(mp, "page discard unable to remove delalloc mapping."); > out_invalidate: > - iomap_invalidatepage(page, 0, PAGE_SIZE); > + iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff); > } > > static const struct iomap_writeback_ops xfs_writeback_ops = { > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 172b3397a1a3..5bd3cac4df9c 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -221,7 +221,7 @@ struct iomap_writeback_ops { > * Optional, allows the file system to discard state on a page where > * we failed to submit any I/O. > */ > - void (*discard_page)(struct page *page); > + void (*discard_page)(struct page *page, loff_t fileoff); > }; > > struct iomap_writepage_ctx { > -- > 2.25.4 >